Improved lignocellulose conversion to biofuels with thermophilic bacteria and thermostable enzymes.

PubMed

Bhalla, Aditya; Bansal, Namita; Kumar, Sudhir; Bischoff, Kenneth M; Sani, Rajesh K

2013-01-01

Second-generation feedstock, especially nonfood lignocellulosic biomass is a potential source for biofuel production. Cost-intensive physical, chemical, biological pretreatment operations and slow enzymatic hydrolysis make the overall process of lignocellulosic conversion into biofuels less economical than available fossil fuels. Lignocellulose conversions carried out at ≤ 50 °C have several limitations. Therefore, this review focuses on the importance of thermophilic bacteria and thermostable enzymes to overcome the limitations of existing lignocellulosic biomass conversion processes. The influence of high temperatures on various existing lignocellulose conversion processes and those that are under development, including separate hydrolysis and fermentation, simultaneous saccharification and fermentation, and extremophilic consolidated bioprocess are also discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

Biological conversion of pyrolytic products to ethanol and lipids

NASA Astrophysics Data System (ADS)

Lian, Jieni

Pyrolysis is a promising technology that can convert up to 75 % of lignocellulosic biomass into crude bio-oil. However, due to the complex chemical compositions of bio-oil, its further refining into fuels and high value chemicals faces great challenges. This dissertation research proposed new technologies for biological conversion of pyrolytic products derived from cellulose and hemicellulose, such as anhydrosugars and carbolic acids to fuels and chemicals. First, the pyrolytic anhydrosugars (chiefly levoglucosan (LG)) were hydrolysed into glucose followed by neutralization, detoxification and fermentation to produce ethanol by ethanogenetic yeast and lipids by oleaginous yeasts. Second, a novel process for the conversion of C1-C4 pyrolytic products to lipid with oleaginous yeasts was investigated. Third, oleaginous yeasts that can directly convert LG to lipids were studied and a recombined yeast with LG kinase was constructed for the direct convertion of LG into lipids. This allowed a reduction of existing process for LG fermentation from four steps into two steps and eliminated the need for acids and bases as well as the disposal of chemicals. The development of genetic modified organisms with LG kinase opens a promising avenue for the direct LG fermentation to produce a wide range of fuels and chemicals. The simplification of LG utilization process would enhance the economic viability of this technology.

Integrated Electrochemical Processes for CO 2 Capture and Conversion to Commodity Chemicals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hatton, T. Alan; Jamison, Timothy

2013-09-30

The Massachusetts Institute of Technology (MIT) and Siemens Corporations (SCR) are developing new chemical synthesis processes for commodity chemicals from CO 2. The process is assessed as a novel chemical sequestration technology that utilizes CO 2 from dilute gas streams generated at industrial carbon emitters as a raw material to produce useful commodity chemicals. Work at Massachusetts Institute of Technology (MIT) commenced on October 1st, 2010, and finished on September 30th, 2013. During this period, we have investigated and accomplished five objectives that mainly focused on converting CO 2 into high-value chemicals: 1) Electrochemical assessment of catalytic transformation of COmore » 2 and epoxides to cyclic carbonates; 2) Investigation of organocatalytic routes to convert CO 2 and epoxide to cyclic carbonates; 3) Investigation of CO 2 Capture and conversion using simple olefins under continuous flow; 4) Microwave assisted synthesis of cyclic carbonates from olefins using sodium bicarbonates in a green pathway; 5) Life cycle analyses of integrated chemical sequestration process. In this final report, we will describe the detailed study performed during the three year period and findings and conclusions drawn from our research.« less

Method for conversion of carbohydrate polymers to value-added chemical products

DOEpatents

Zhang, Zongchao C [Norwood, NJ; Brown, Heather M [Kennewick, WA; Su, Yu [Richland, WA

2012-02-07

Methods are described for conversion of carbohydrate polymers in ionic liquids, including cellulose, that yield value-added chemicals including, e.g., glucose and 5-hydroxylmethylfurfural (HMF) at temperatures below 120.degree. C. Catalyst compositions that include various mixed metal halides are described that are selective for specified products with yields, e.g., of up to about 56% in a single step process.

Biocatalytic conversion of methane to methanol as a key step for development of methane-based biorefineries.

PubMed

Hwang, In Yeub; Lee, Seung Hwan; Choi, Yoo Seong; Park, Si Jae; Na, Jeong Geol; Chang, In Seop; Kim, Choongik; Kim, Hyun Cheol; Kim, Yong Hwan; Lee, Jin Won; Lee, Eun Yeol

2014-12-28

Methane is considered as a next-generation carbon feedstock owing to the vast reserves of natural and shale gas. Methane can be converted to methanol by various methods, which in turn can be used as a starting chemical for the production of value-added chemicals using existing chemical conversion processes. Methane monooxygenase is the key enzyme that catalyzes the addition of oxygen to methane. Methanotrophic bacteria can transform methane to methanol by inhibiting methanol dehydrogenase. In this paper, we review the recent progress made on the biocatalytic conversion of methane to methanol as a key step for methane-based refinery systems and discuss future prospects for this technology.

Effective Charge Carrier Utilization in Photocatalytic Conversions.

PubMed

Zhang, Peng; Wang, Tuo; Chang, Xiaoxia; Gong, Jinlong

2016-05-17

Continuous efforts have been devoted to searching for sustainable energy resources to alleviate the upcoming energy crises. Among various types of new energy resources, solar energy has been considered as one of the most promising choices, since it is clean, sustainable, and safe. Moreover, solar energy is the most abundant renewable energy, with a total power of 173 000 terawatts striking Earth continuously. Conversion of solar energy into chemical energy, which could potentially provide continuous and flexible energy supplies, has been investigated extensively. However, the conversion efficiency is still relatively low since complicated physical, electrical, and chemical processes are involved. Therefore, carefully designed photocatalysts with a wide absorption range of solar illumination, a high conductivity for charge carriers, a small number of recombination centers, and fast surface reaction kinetics are required to achieve a high activity. This Account describes our recent efforts to enhance the utilization of charge carriers for semiconductor photocatalysts toward efficient solar-to-chemical energy conversion. During photocatalytic reactions, photogenerated electrons and holes are involved in complex processes to convert solar energy into chemical energy. The initial step is the generation of charge carriers in semiconductor photocatalysts, which could be enhanced by extending the light absorption range. Integration of plasmonic materials and introduction of self-dopants have been proved to be effective methods to improve the light absorption ability of photocatalysts to produce larger amounts of photogenerated charge carriers. Subsequently, the photogenerated electrons and holes migrate to the surface. Therefore, acceleration of the transport process can result in enhanced solar energy conversion efficiency. Different strategies such as morphology control and conductivity improvement have been demonstrated to achieve this goal. Fine-tuning of the morphology of nanostructured photocatalysts can reduce the migration distance of charge carriers. Improving the conductivity of photocatalysts by using graphitic materials can also improve the transport of charge carriers. Upon charge carrier migration, electrons and holes also tend to recombine. The suppression of recombination can be achieved by constructing heterojunctions that enhance charge separation in the photocatalysts. Surface states acting as recombination centers should also be removed to improve the photocatalytic efficiency. Moreover, surface reactions, which are the core chemical processes during the solar energy conversion, can be enhanced by applying cocatalysts as well as suppressing side reactions. All of these strategies have been proved to be essential for enhancing the activities of semiconductor photocatalysts. It is hoped that delicate manipulation of photogenerated charge carriers in semiconductor photocatalysts will hold the key to effective solar-to-chemical energy conversion.

CFD studies on biomass thermochemical conversion.

PubMed

Wang, Yiqun; Yan, Lifeng

2008-06-01

Thermochemical conversion of biomass offers an efficient and economically process to provide gaseous, liquid and solid fuels and prepare chemicals derived from biomass. Computational fluid dynamic (CFD) modeling applications on biomass thermochemical processes help to optimize the design and operation of thermochemical reactors. Recent progression in numerical techniques and computing efficacy has advanced CFD as a widely used approach to provide efficient design solutions in industry. This paper introduces the fundamentals involved in developing a CFD solution. Mathematical equations governing the fluid flow, heat and mass transfer and chemical reactions in thermochemical systems are described and sub-models for individual processes are presented. It provides a review of various applications of CFD in the biomass thermochemical process field.

CFD Studies on Biomass Thermochemical Conversion

PubMed Central

Wang, Yiqun; Yan, Lifeng

2008-01-01

Thermochemical conversion of biomass offers an efficient and economically process to provide gaseous, liquid and solid fuels and prepare chemicals derived from biomass. Computational fluid dynamic (CFD) modeling applications on biomass thermochemical processes help to optimize the design and operation of thermochemical reactors. Recent progression in numerical techniques and computing efficacy has advanced CFD as a widely used approach to provide efficient design solutions in industry. This paper introduces the fundamentals involved in developing a CFD solution. Mathematical equations governing the fluid flow, heat and mass transfer and chemical reactions in thermochemical systems are described and sub-models for individual processes are presented. It provides a review of various applications of CFD in the biomass thermochemical process field. PMID:19325848

A mild thermomechanical process for the enzymatic conversion of radiata pine into fermentable sugars and lignin.

PubMed

Suckling, Ian D; Jack, Michael W; Lloyd, John A; Murton, Karl D; Newman, Roger H; Stuthridge, Trevor R; Torr, Kirk M; Vaidya, Alankar A

2017-01-01

Conversion of softwoods into sustainable fuels and chemicals is important for parts of the world where softwoods are the dominant forest species. While they have high theoretical sugar yields, softwoods are amongst the most recalcitrant feedstocks for enzymatic processes, typically requiring both more severe pretreatment conditions and higher enzyme doses than needed for other lignocellulosic feedstocks. Although a number of processes have been proposed for converting softwoods into sugars suitable for fuel and chemical production, there is still a need for a high-yielding, industrially scalable and cost-effective conversion route. We summarise work leading to the development of an efficient process for the enzymatic conversion of radiata pine ( Pinus radiata ) into wood sugars. The process involves initial pressurised steaming of wood chips under relatively mild conditions (173 °C for 3-72 min) without added acid catalyst. The steamed chips then pass through a compression screw to squeeze out a pressate rich in solubilised hemicelluloses. The pressed chips are disc-refined and wet ball-milled to produce a substrate which is rapidly saccharified using commercially available enzyme cocktails. Adding 0.1% polyethylene glycol during saccharification was found to be particularly effective with these substrates, reducing enzyme usage to acceptable levels, e.g. 5 FPU/g OD substrate. The pressate is separately hydrolysed using acid, providing additional hemicellulose-derived sugars, for an overall sugar yield of 535 kg/ODT chips (76% of theoretical). The total pretreatment energy input is comparable to other processes, with the additional energy for attrition being balanced by a lower thermal energy requirement. This pretreatment strategy produces substrates with low levels of fermentation inhibitors, so the glucose-rich mainline and pressate syrups can be fermented to ethanol without detoxification. The lignin from the process remains comparatively unmodified, as evident from the level of retained β-ether interunit linkages, providing an opportunity for conversion into saleable co-products. This process is an efficient route for the enzymatic conversion of radiata pine, and potentially other softwoods, into a sugar syrup suitable for conversion into fuels and chemicals. Furthermore, the process uses standard equipment that is largely proven at commercial scale, de-risking process scale-up.

Techno-economic analysis of biocatalytic processes for production of alkene expoxides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borole, Abhijeet P

2007-01-01

A techno-economic analysis of two different bioprocesses was conducted, one for the conversion of propylene to propylene oxide (PO) and other for conversion of styrene to styrene expoxide (SO). The first process was a lipase-mediated chemo-enzymatic reaction, whereas the second one was a one-step enzymatic process using chloroperoxidase. The PO produced through the chemo-enzymatic process is a racemic product, whereas the latter process (based on chloroperoxidase) produces an enantio-pure product. The former process thus falls under the category of high-volume commodity chemical (PO); whereas the latter is a low-volume, high-value product (SO).A simulation of the process was conducted using themore » bioprocess engineering software SuperPro Designer v6.0 (Intelligen, Inc., Scotch Plains, NJ) to determine the economic feasibility of the process. The purpose of the exercise was to compare biocatalytic processes with existing chemical processes for production of alkene expoxides. The results show that further improvements are needed in improving biocatalyst stability to make these bioprocesses competitive with chemical processes.« less

Defense Waste Processing Facility Nitric- Glycolic Flowsheet Chemical Process Cell Chemistry: Part 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zamecnik, J.; Edwards, T.

The conversions of nitrite to nitrate, the destruction of glycolate, and the conversion of glycolate to formate and oxalate were modeled for the Nitric-Glycolic flowsheet using data from Chemical Process Cell (CPC) simulant runs conducted by Savannah River National Laboratory (SRNL) from 2011 to 2016. The goal of this work was to develop empirical correlation models to predict these values from measureable variables from the chemical process so that these quantities could be predicted a-priori from the sludge or simulant composition and measurable processing variables. The need for these predictions arises from the need to predict the REDuction/OXidation (REDOX) statemore » of the glass from the Defense Waste Processing Facility (DWPF) melter. This report summarizes the work on these correlations based on the aforementioned data. Previous work on these correlations was documented in a technical report covering data from 2011-2015. This current report supersedes this previous report. Further refinement of the models as additional data are collected is recommended.« less

Chemical Consequences of Radioactive Decay and their Biological Implications.

PubMed

DeJesus, Onofre T

2017-11-10

The chemical effects of radioactive decay arise from (1) transmutation, (2) formation of charged daughter nuclei, (3) recoil of the daughter nuclei, (4) electron "shakeoff" phenomenon and (5) vacancy cascade in decays via electron capture and internal conversion. This review aims to reiterate what has been known for a long time regarding the chemical consequences of radioactive decay and gives a historical perspective to the observations that led to their elucidation. The energetics of the recoil process in each decay mode is discussed in relation to the chemical bond between the decaying nucleus and the parent molecule. Special attention is given to the biological effects of the Auger process following decay by electron capture and internal conversion because of their possible utility in internal radiotherapy. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Mechanochemical Energy Conversion

ERIC Educational Resources Information Center

Pines, E.; And Others

1973-01-01

Summarizes the thermodynamics of macromolecular systems, including theories and experiments of cyclic energy conversion with rubber and collagen as working substances. Indicates that an early introduction into the concept of chemical potential and solution thermodynamics is made possible through the study of the cyclic processes. (CC)

Electric terminal performance and characterization of solid oxide fuel cells and systems

NASA Astrophysics Data System (ADS)

Lindahl, Peter Allan

Solid Oxide Fuel Cells (SOFCs) are electrochemical devices which can effect efficient, clean, and quiet conversion of chemical to electrical energy. In contrast to conventional electricity generation systems which feature multiple discrete energy conversion processes, SOFCs are direct energy conversion devices. That is, they feature a fully integrated chemical to electrical energy conversion process where the electric load demanded of the cell intrinsically drives the electrochemical reactions and associated processes internal to the cell. As a result, the cell's electric terminals provide a path for interaction between load side electric demand and the conversion side processes. The implication of this is twofold. First, the magnitude and dynamic characteristics of the electric load demanded of the cell can directly impact the long-term efficacy of the cell's chemical to electrical energy conversion. Second, the electric terminal response to dynamic loads can be exploited for monitoring the cell's conversion side processes and used in diagnostic analysis and degradation-mitigating control schemes. This dissertation presents a multi-tier investigation into this electric terminal based performance characterization of SOFCs through the development of novel test systems, analysis techniques and control schemes. First, a reference-based simulation system is introduced. This system scales up the electric terminal performance of a prototype SOFC system, e.g. a single fuel cell, to that of a full power-level stack. This allows realistic stack/load interaction studies while maintaining explicit ability for post-test analysis of the prototype system. Next, a time-domain least squares fitting method for electrochemical impedance spectroscopy (EIS) is developed for reduced-time monitoring of the electrochemical and physicochemical mechanics of the fuel cell through its electric terminals. The utility of the reference-based simulator and the EIS technique are demonstrated through their combined use in the performance testing of a hybrid-source power management (HSPM) system designed to allow in-situ EIS monitoring of a stack under dynamic loading conditions. The results from the latter study suggest that an HSPM controller allows an opportunity for in-situ electric terminal monitoring and control-based mitigation of SOFC degradation. As such, an exploration of control-based SOFC degradation mitigation is presented and ideas for further work are suggested.

Potential and challenges of zeolite chemistry in the catalytic conversion of biomass.

PubMed

Ennaert, Thijs; Van Aelst, Joost; Dijkmans, Jan; De Clercq, Rik; Schutyser, Wouter; Dusselier, Michiel; Verboekend, Danny; Sels, Bert F

2016-02-07

Increasing demand for sustainable chemicals and fuels has pushed academia and industry to search for alternative feedstocks replacing crude oil in traditional refineries. As a result, an immense academic attention has focused on the valorisation of biomass (components) and derived intermediates to generate valuable platform chemicals and fuels. Zeolite catalysis plays a distinct role in many of these biomass conversion routes. This contribution emphasizes the progress and potential in zeolite catalysed biomass conversions and relates these to concepts established in existing petrochemical processes. The application of zeolites, equipped with a variety of active sites, in Brønsted acid, Lewis acid, or multifunctional catalysed reactions is discussed and generalised to provide a comprehensive overview. In addition, the feedstock shift from crude oil to biomass involves new challenges in developing fields, like mesoporosity and pore interconnectivity of zeolites and stability of zeolites in liquid phase. Finally, the future challenges and perspectives of zeolites in the processing of biomass conversion are discussed.

A cure-rate model for the Shuttle filament-wound case

NASA Technical Reports Server (NTRS)

Cagliostro, D. E.; Islas, A.; Hsu, Ming-Ta

1987-01-01

An epoxy and carbon fiber composite has been used to produce a light-weight rocket case for the Space Shuttle. A kinetic model is developed which can predict the extent of epoxy conversion during the winding and curing of the case. The model accounts for both chemical and physical kinetics. In the model, chemical kinetics occur exclusively up to the time the transition temperature equals the reaction temperature. At this point the resin begins to solidify and the rate of this process limits the rate of epoxy conversion. A comparison of predicted and actual epoxy conversion is presented for isothermal and temperature programmed cure schedules.

Biological valorization of low molecular weight lignin.

PubMed

Abdelaziz, Omar Y; Brink, Daniel P; Prothmann, Jens; Ravi, Krithika; Sun, Mingzhe; García-Hidalgo, Javier; Sandahl, Margareta; Hulteberg, Christian P; Turner, Charlotta; Lidén, Gunnar; Gorwa-Grauslund, Marie F

2016-12-01

Lignin is a major component of lignocellulosic biomass and as such, it is processed in enormous amounts in the pulp and paper industry worldwide. In such industry it mainly serves the purpose of a fuel to provide process steam and electricity, and to a minor extent to provide low grade heat for external purposes. Also from other biorefinery concepts, including 2nd generation ethanol, increasing amounts of lignin will be generated. Other uses for lignin - apart from fuel production - are of increasing interest not least in these new biorefinery concepts. These new uses can broadly be divided into application of the polymer as such, native or modified, or the use of lignin as a feedstock for the production of chemicals. The present review focuses on the latter and in particular the advances in the biological routes for chemicals production from lignin. Such a biological route will likely involve an initial depolymerization, which is followed by biological conversion of the obtained smaller lignin fragments. The conversion can be either a short catalytic conversion into desired chemicals, or a longer metabolic conversion. In this review, we give a brief summary of sources of lignin, methods of depolymerization, biological pathways for conversion of the lignin monomers and the analytical tools necessary for characterizing and evaluating key lignin attributes. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Humus-reducing microorganisms and their valuable contribution in environmental processes.

PubMed

Martinez, Claudia M; Alvarez, Luis H; Celis, Lourdes B; Cervantes, Francisco J

2013-12-01

Humus constitutes a very abundant class of organic compounds that are chemically heterogeneous and widely distributed in terrestrial and aquatic environments. Evidence accumulated during the last decades indicating that humic substances play relevant roles on the transport, fate, and redox conversion of organic and inorganic compounds both in chemically and microbially driven reactions. The present review underlines the contribution of humus-reducing microorganisms in relevant environmental processes such as biodegradation of recalcitrant pollutants and mitigation of greenhouse gases emission in anoxic ecosystems, redox conversion of industrial contaminants in anaerobic wastewater treatment systems, and on the microbial production of nanocatalysts and alternative energy sources.

Bioelectrochemical Integration of Waste Heat Recovery, Waste-to- Energy Conversion, and Waste-to-Chemical Conversion with Industrial Gas and Chemical Manufacturing Processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mac Dougall, James

2016-02-05

Many U.S. manufacturing facilities generate unrecovered, low-grade waste heat, and also generate or are located near organic-content waste effluents. Bioelectrochemical systems, such as microbial fuel cells and microbial electrolysis cells, provide a means to convert organic-content effluents into electric power and useful chemical products. A novel biochemical electrical system for industrial manufacturing processes uniquely integrates both waste heat recovery and waste effluent conversion, thereby significantly reducing manufacturing energy requirements. This project will enable the further development of this technology so that it can be applied across a wide variety of US manufacturing segments, including the chemical, food, pharmaceutical, refinery, andmore » pulp and paper industries. It is conservatively estimated that adoption of this technology could provide nearly 40 TBtu/yr of energy, or more than 1% of the U.S. total industrial electricity use, while reducing CO 2 emissions by more than 6 million tons per year. Commercialization of this technology will make a significant contribution to DOE’s Industrial Technology Program goals for doubling energy efficiency and providing a more robust and competitive domestic manufacturing base.« less

Biomass in the manufacture of industrial products—the use of proteins and amino acids

PubMed Central

Peter, Francisc; Sanders, Johan

2007-01-01

The depletion in fossil feedstocks, increasing oil prices, and the ecological problems associated with CO2 emissions are forcing the development of alternative resources for energy, transport fuels, and chemicals: the replacement of fossil resources with CO2 neutral biomass. Allied with this, the conversion of crude oil products utilizes primary products (ethylene, etc.) and their conversion to either materials or (functional) chemicals with the aid of co-reagents such as ammonia and various process steps to introduce functionalities such as -NH2 into the simple structures of the primary products. Conversely, many products found in biomass often contain functionalities. Therefore, it is attractive to exploit this to bypass the use, and preparation of, co-reagents as well as eliminating various process steps by utilizing suitable biomass-based precursors for the production of chemicals. It is the aim of this mini-review to describe the scope of the possibilities to generate current functionalized chemical materials using amino acids from biomass instead of fossil resources, thereby taking advantage of the biomass structure in a more efficient way than solely utilizing biomass for the production of fuels or electricity. PMID:17387469

The role of chemistry in the energy challenge.

PubMed

Schlögl, Robert

2010-02-22

Chemistry with its key targets of providing materials and processes for conversion of matter is at the center stage of the energy challenge. Most energy conversion systems work on (bio)chemical energy carriers and require for their use suitable process and material solutions. The enormous scale of their application demands optimization beyond the incremental improvement of empirical discoveries. Knowledge-based systematic approaches are mandatory to arrive at scalable and sustainable solutions. Chemistry for energy, "ENERCHEM" contributes in many ways already today to the use of fossil energy carriers. Optimization of these processes exemplified by catalysis for fuels and chemicals production or by solid-state lightning can contribute in the near future substantially to the dual challenge of energy use and climate protection being in fact two sides of the same challenge. The paper focuses on the even greater role that ENERCHEM will have to play in the era of renewable energy systems where the storage of solar energy in chemical carries and batteries is a key requirement. A multidisciplinary and diversified approach is suggested to arrive at a stable and sustainable system of energy conversion processes. The timescales for transformation of the present energy scenario will be decades and the resources will be of global economic dimensions. ENERCHEM will have to provide the reliable basis for such technologies based on deep functional understanding.

Separation of Corn Fiber and Conversion to Fuels and Chemicals Phase II: Pilot-scale Operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abbas, Charles; Beery, Kyle; Orth, Rick

2007-09-28

The purpose of the Department of Energy (DOE)-supported corn fiber conversion project, “Separation of Corn Fiber and Conversion to Fuels and Chemicals Phase II: Pilot-scale Operation” is to develop and demonstrate an integrated, economical process for the separation of corn fiber into its principal components to produce higher value-added fuel (ethanol and biodiesel), nutraceuticals (phytosterols), chemicals (polyols), and animal feed (corn fiber molasses). This project has successfully demonstrated the corn fiber conversion process on the pilot scale, and ensured that the process will integrate well into existing ADM corn wet-mills. This process involves hydrolyzing the corn fiber to solubilize 50%more » of the corn fiber as oligosaccharides and soluble protein. The solubilized fiber is removed and the remaining fiber residue is solvent extracted to remove the corn fiber oil, which contains valuable phytosterols. The extracted oil is refined to separate the phytosterols and the remaining oil is converted to biodiesel. The de-oiled fiber is enzymatically hydrolyzed and remixed with the soluble oligosaccharides in a fermentation vessel where it is fermented by a recombinant yeast, which is capable of fermenting the glucose and xylose to produce ethanol. The fermentation broth is distilled to remove the ethanol. The stillage is centrifuged to separate the yeast cell mass from the soluble components. The yeast cell mass is sold as a high-protein yeast cream and the remaining sugars in the stillage can be purified to produce a feedstock for catalytic conversion of the sugars to polyols (mainly ethylene glycol and propylene glycol) if desirable. The remaining materials from the purification step and any materials remaining after catalytic conversion are concentrated and sold as a corn fiber molasses. Additional high-value products are being investigated for the use of the corn fiber as a dietary fiber sources.« less

Rational Design of Mixed-Metal Oxides for Chemical Looping Combustion of Coal via Coupled Computational-Experimental Studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mishra, Amit; Li, Fanxing; Santiso, Erik

Energy and global climate change are two grand challenges to the modern society. An urgent need exists for development of clean and efficient energy conversion processes. The chemical looping strategy, which utilizes regenerable oxygen carriers (OCs) to indirectly convert carbonaceous fuels via redox reactions, is considered to be one of the more promising approaches for CO2 capture by the U.S. Department of Energy (USDOE). To date, most long-term chemical looping operations were conducted using gaseous fuels, even though direct conversion of coal is more desirable from both economics and CO2 capture viewpoints. The main challenges for direct coal conversion residemore » in the stringent requirements on oxygen carrier performances. In addition, coal char and volatile compounds are more challenging to convert than gaseous fuels. A promising approach for direct conversion of coal is the so called chemical looping with oxygen uncoupling (CLOU) technique. In the CLOU process, a metal oxide that decomposes at the looping temperature, and releases oxygen to the gas phase is used as the OC. The overarching objective of this project was to discover the fundamental principles for rational design and optimization of oxygen carriers (OC) in coal chemical looping combustion (CLC) processes. It directly addresses Topic Area B of the funding opportunity announcement (FOA) in terms of “predictive description of the phase behavior and mechanical properties” of “mixed metal oxide” based OCs and rational development of new OC materials with superior functionality. This was achieved through studies exploring i) iron-containing mixed-oxide composites as oxygen carriers for CLOU, ii) Ca1-xAxMnO3-δ (A = Sr and Ba) as oxygen carriers for CLOU, iii) CaMn1-xBxO3-δ (B=Al, V, Fe, Co, and Ni) as oxygen carrier for CLOU and iv) vacancy creation energy in Mn-containing perovskites as an indicator chemical looping with oxygen uncoupling.« less

Catalytic Conversion of Carbohydrates to Initial Platform Chemicals: Chemistry and Sustainability.

PubMed

Mika, László T; Cséfalvay, Edit; Németh, Áron

2018-01-24

The replacement of fossil resources that currently provide more than 90% of our energy needs and feedstocks of the chemical industry in combination with reduced emission of carbon dioxide is one of the most pressing challenges of mankind. Biomass as a globally available resource has been proposed as an alternative feedstock for production of basic building blocks, which could partially or even fully replace the currently utilized fossil-based ones in well-established chemical processes. The destruction of lignocellulosic feed followed by oxygen removal from its cellulose and hemicellulose content by catalytic processes results in the formation of initial platform chemicals (IPCs). However, their sustainable production strongly depends on the availability of resources, their efficient or even industrially viable conversion processes, and replenishment time of feedstocks. Herein, we overview recent advances and developments in catalytic transformations of the carbohydrate content of lignocellulosic biomass to IPCs (i.e., ethanol, 3-hydroxypropionic acid, isoprene, succinic and levulinic acids, furfural, and 5-hydroxymethylfurfural). The mechanistic aspects, development of new catalysts, different efficiency indicators (yield and selectivity), and conversion conditions of their production are presented and compared. The potential biochemical production routes utilizing recently engineered microorganisms are reviewed, as well. The sustainability metrics that could be applied to the chemical industry (individual set of sustainability indicators, composite indices methods, material and energy flow analysis-based metrics, and ethanol equivalents) are also overviewed as well as an outlook is provided to highlight challenges and opportunities associated with this huge research area.

Highly efficient chemical process to convert mucic acid into adipic acid and DFT studies of the mechanism of the rhenium-catalyzed deoxydehydration.

PubMed

Li, Xiukai; Wu, Di; Lu, Ting; Yi, Guangshun; Su, Haibin; Zhang, Yugen

2014-04-14

The production of bulk chemicals and fuels from renewable bio-based feedstocks is of significant importance for the sustainability of human society. Adipic acid, as one of the most-demanded drop-in chemicals from a bioresource, is used primarily for the large-volume production of nylon-6,6 polyamide. It is highly desirable to develop sustainable and environmentally friendly processes for the production of adipic acid from renewable feedstocks. However, currently there is no suitable bio-adipic acid synthesis process. Demonstrated herein is the highly efficient synthetic protocol for the conversion of mucic acid into adipic acid through the oxorhenium-complex-catalyzed deoxydehydration (DODH) reaction and subsequent Pt/C-catalyzed transfer hydrogenation. Quantitative yields (99 %) were achieved for the conversion of mucic acid into muconic acid and adipic acid either in separate sequences or in a one-step process. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Detection of Cell Wall Chemical Variation in Zea Mays Mutants Using Near-Infrared Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buyck, N.; Thomas, S.

Corn stover is regarded as the prime candidate feedstock material for commercial biomass conversion in the United States. Variations in chemical composition of Zea mays cell walls can affect biomass conversion process yields and economics. Mutant lines were constructed by activating a Mu transposon system. The cell wall chemical composition of 48 mutant families was characterized using near-infrared (NIR) spectroscopy. NIR data were analyzed using a multivariate statistical analysis technique called Principal Component Analysis (PCA). PCA of the NIR data from 349 maize leaf samples reveals 57 individuals as outliers on one or more of six Principal Components (PCs) atmore » the 95% confidence interval. Of these, 19 individuals from 16 families are outliers on either PC3 (9% of the variation) or PC6 (1% of the variation), the two PCs that contain information about cell wall polymers. Those individuals for which altered cell wall chemistry is confirmed with wet chemical analysis will then be subjected to fermentation analysis to determine whether or not biomass conversion process kinetics, yields and/or economics are significantly affected. Those mutants that provide indications for a decrease in process cost will be pursued further to identify the gene(s) responsible for the observed changes in cell wall composition and associated changes in process economics. These genes will eventually be incorporated into maize breeding programs directed at the development of a truly dual use crop.« less

Comparative life cycle assessment of lignocellulosic ethanol production: biochemical versus thermochemical conversion.

PubMed

Mu, Dongyan; Seager, Thomas; Rao, P Suresh; Zhao, Fu

2010-10-01

Lignocellulosic biomass can be converted into ethanol through either biochemical or thermochemical conversion processes. Biochemical conversion involves hydrolysis and fermentation while thermochemical conversion involves gasification and catalytic synthesis. Even though these routes produce comparable amounts of ethanol and have similar energy efficiency at the plant level, little is known about their relative environmental performance from a life cycle perspective. Especially, the indirect impacts, i.e. emissions and resource consumption associated with the production of various process inputs, are largely neglected in previous studies. This article compiles material and energy flow data from process simulation models to develop life cycle inventory and compares the fossil fuel consumption, greenhouse gas emissions, and water consumption of both biomass-to-ethanol production processes. The results are presented in terms of contributions from feedstock, direct, indirect, and co-product credits for four representative biomass feedstocks i.e., wood chips, corn stover, waste paper, and wheat straw. To explore the potentials of the two conversion pathways, different technological scenarios are modeled, including current, 2012 and 2020 technology targets, as well as different production/co-production configurations. The modeling results suggest that biochemical conversion has slightly better performance on greenhouse gas emission and fossil fuel consumption, but that thermochemical conversion has significantly less direct, indirect, and life cycle water consumption. Also, if the thermochemical plant operates as a biorefinery with mixed alcohol co-products separated for chemicals, it has the potential to achieve better performance than biochemical pathway across all environmental impact categories considered due to higher co-product credits associated with chemicals being displaced. The results from this work serve as a starting point for developing full life cycle assessment model that facilitates effective decision-making regarding lignocellulosic ethanol production.

Comparative Life Cycle Assessment of Lignocellulosic Ethanol Production: Biochemical Versus Thermochemical Conversion

NASA Astrophysics Data System (ADS)

Mu, Dongyan; Seager, Thomas; Rao, P. Suresh; Zhao, Fu

2010-10-01

Lignocellulosic biomass can be converted into ethanol through either biochemical or thermochemical conversion processes. Biochemical conversion involves hydrolysis and fermentation while thermochemical conversion involves gasification and catalytic synthesis. Even though these routes produce comparable amounts of ethanol and have similar energy efficiency at the plant level, little is known about their relative environmental performance from a life cycle perspective. Especially, the indirect impacts, i.e. emissions and resource consumption associated with the production of various process inputs, are largely neglected in previous studies. This article compiles material and energy flow data from process simulation models to develop life cycle inventory and compares the fossil fuel consumption, greenhouse gas emissions, and water consumption of both biomass-to-ethanol production processes. The results are presented in terms of contributions from feedstock, direct, indirect, and co-product credits for four representative biomass feedstocks i.e., wood chips, corn stover, waste paper, and wheat straw. To explore the potentials of the two conversion pathways, different technological scenarios are modeled, including current, 2012 and 2020 technology targets, as well as different production/co-production configurations. The modeling results suggest that biochemical conversion has slightly better performance on greenhouse gas emission and fossil fuel consumption, but that thermochemical conversion has significantly less direct, indirect, and life cycle water consumption. Also, if the thermochemical plant operates as a biorefinery with mixed alcohol co-products separated for chemicals, it has the potential to achieve better performance than biochemical pathway across all environmental impact categories considered due to higher co-product credits associated with chemicals being displaced. The results from this work serve as a starting point for developing full life cycle assessment model that facilitates effective decision-making regarding lignocellulosic ethanol production.

Highly efficient conversion of plant oil to bio-aviation fuel and valuable chemicals by combination of enzymatic transesterification, olefin cross-metathesis, and hydrotreating.

PubMed

Wang, Meng; Chen, Mojin; Fang, Yunming; Tan, Tianwei

2018-01-01

The production of fuels and chemicals from renewable resources is increasingly important due to the environmental concern and depletion of fossil fuel. Despite the fast technical development in the production of aviation fuels, there are still several shortcomings such as a high cost of raw materials, a low yield of aviation fuels, and poor process techno-economic consideration. In recent years, olefin metathesis has become a powerful and versatile tool for generating new carbon-carbon bonds. The cross-metathesis reaction, one kind of metathesis reaction, has a high potential to efficiently convert plant oil into valuable chemicals, such as α-olefin and bio-aviation fuel by combining with a hydrotreatment process. In this research, an efficient, four-step conversion of plant oil into bio-aviation fuel and valuable chemicals was developed by the combination of enzymatic transesterification, olefin cross-metathesis, and hydrotreating. Firstly, plant oil including oil with poor properties was esterified to fatty acid methyl esters by an enzyme-catalyzed process. Secondly, the fatty acid methyl esters were partially hydrotreated catalytically to transform poly-unsaturated fatty acid such as linoleic acid into oleic acid. The olefin cross-metathesis then transformed the oleic acid methyl ester (OAME) into 1-decene and 1-decenoic acid methyl ester (DAME). The catalysts used in this process were prepared/selected in function of the catalytic reaction and the reaction conditions were optimized. The carbon efficiency analysis of the new process illustrated that it was more economically feasible than the traditional hydrotreatment process. A highly efficient conversion process of plant oil into bio-aviation fuel and valuable chemicals by the combination of enzymatic transesterification, olefin cross-metathesis, and hydrotreatment with prepared and selected catalysts was designed. The reaction conditions were optimized. Plant oil was transformed into bio-aviation fuel and a high value α-olefin product with high carbon utilization.

Production of chemicals and fuels from biomass

DOEpatents

Woods, Elizabeth; Qiao, Ming; Myren, Paul; Cortright, Randy D.; Kania, John

2015-12-15

Described are methods, reactor systems, and catalysts for converting biomass to fuels and chemicals in a batch and/or continuous process. The process generally involves the conversion of water insoluble components of biomass, such as hemicellulose, cellulose and lignin, to volatile C.sub.2+O.sub.1-2 oxygenates, such as alcohols, ketones, cyclic ethers, esters, carboxylic acids, aldehydes, and mixtures thereof. In certain applications, the volatile C.sub.2+O.sub.1-2 oxygenates can be collected and used as a final chemical product, or used in downstream processes to produce liquid fuels, chemicals and other products.

Formation Mechanism of Discoloration on Die-Cast AZ91D Components Surface After Chemical Conversion

NASA Astrophysics Data System (ADS)

Liu, Bao-sheng; Wei, Ying-hui; Hou, Li-feng

2013-01-01

A notebook (NB) computer component was manufactured from AZ91D Mg alloy by a die-casting process. After chemical conversion treatment, a discoloration was noted on the component surface. The source of this discoloration has been studied in detail by scanning electron microscopy, energy dispersive spectroscopy, and spark atomic absorption spectroscopy. The corrosion resistance was also measured by potentiodynamic polarization, hydrogen evolution and salt spray testing. The formation mechanism for the discoloration which was caused by the residue left behind by excess mold release agent sprayed during the die-casting was discussed in detail. After chemical conversion treatment, the residual-baked mold release agent was apparent on the component surface as "white ash." Consequently, it degraded seriously both the appearance and the corrosion resistance of the manufactured component.

Ultrafast Electron Dynamics in Solar Energy Conversion.

PubMed

Ponseca, Carlito S; Chábera, Pavel; Uhlig, Jens; Persson, Petter; Sundström, Villy

2017-08-23

Electrons are the workhorses of solar energy conversion. Conversion of the energy of light to electricity in photovoltaics, or to energy-rich molecules (solar fuel) through photocatalytic processes, invariably starts with photoinduced generation of energy-rich electrons. The harvesting of these electrons in practical devices rests on a series of electron transfer processes whose dynamics and efficiencies determine the function of materials and devices. To capture the energy of a photogenerated electron-hole pair in a solar cell material, charges of opposite sign have to be separated against electrostatic attractions, prevented from recombining and being transported through the active material to electrodes where they can be extracted. In photocatalytic solar fuel production, these electron processes are coupled to chemical reactions leading to storage of the energy of light in chemical bonds. With the focus on the ultrafast time scale, we here discuss the light-induced electron processes underlying the function of several molecular and hybrid materials currently under development for solar energy applications in dye or quantum dot-sensitized solar cells, polymer-fullerene polymer solar cells, organometal halide perovskite solar cells, and finally some photocatalytic systems.

Effect of electronegative additives on physical properties and chemical activity of gas discharge plasma

NASA Astrophysics Data System (ADS)

Kuznetsov, D. L.; Filatov, I. E.; Uvarin, V. V.

2018-01-01

Effect of electronegative additives (oxygen O2, sulfur dioxide SO2, carbon disulfide CS2, and carbon tetrachloride CCl4) on physical properties and chemical activity of plasma formed by pulsed corona discharge and by non-self-sustained discharge supported by pulsed electron beam in atmospheric pressure gas mixtures was investigated. It is shown that a decrease in discharge current depends on a sort of the additive and on its concentration. The reason is the difference in rate constants of electron attachment processes for the above molecules. In experiments on volatile organic compounds (VOCs) conversion in air by streamer corona it is obtained that an addition of CCl4 both decreases the discharge current amplitude and increases the VOCs conversion degree. An installation for investigation of electron attachment processes and for study of toxic impurities conversion in plasma formed by non-self-sustained discharge initiated by pulsed nanosecond electron beam is created.

Materials ``alchemy'': Shape-preserving chemical transformation of micro-to-macroscopic 3-D structures

NASA Astrophysics Data System (ADS)

Sandhage, Kenneth H.

2010-06-01

The scalable fabrication of nano-structured materials with complex morphologies and tailorable chemistries remains a significant challenge. One strategy for such synthesis consists of the generation of a solid structure with a desired morphology (a “preform”), followed by reactive conversion of the preform into a new chemistry. Several gas/solid and liquid/solid reaction processes that are capable of such chemical conversion into new micro-to-nano-structured materials, while preserving the macroscopic-to-microscopic preform morphologies, are described in this overview. Such shape-preserving chemical transformation of one material into another could be considered a modern type of materials “alchemy.”

Thermal conversion of biomass to valuable fuels, chemical feedstocks and chemicals

DOEpatents

Peters, William A [Lexington, MA; Howard, Jack B [Winchester, MA; Modestino, Anthony J [Hanson, MA; Vogel, Fredreric [Villigen PSI, CH; Steffin, Carsten R [Herne, DE

2009-02-24

A continuous process for the conversion of biomass to form a chemical feedstock is described. The biomass and an exogenous metal oxide, preferably calcium oxide, or metal oxide precursor are continuously fed into a reaction chamber that is operated at a temperature of at least 1400.degree. C. to form reaction products including metal carbide. The metal oxide or metal oxide precursor is capable of forming a hydrolizable metal carbide. The reaction products are quenched to a temperature of 800.degree. C. or less. The resulting metal carbide is separated from the reaction products or, alternatively, when quenched with water, hydolyzed to provide a recoverable hydrocarbon gas feedstock.

Clean Transformation of Ethanol to Useful Chemicals. The Behavior of a Gold-Modified Silicalite Catalyst.

PubMed

Falletta, Ermelinda; Rossi, Michele; Teles, Joaquim Henrique; Della Pina, Cristina

2016-03-19

Upon addition of gold to silicalite-1 pellets (a MFI-type zeolite), the vapor phase oxidation of ethanol could be addressed to acetaldehyde or acetic acid formation. By optimizing the catalyst composition and reaction conditions, the conversion of ethanol could be tuned to acetaldehyde with 97% selectivity at 71% conversion or to acetic acid with 78% selectivity at total conversion. Considering that unloaded silicalite-1 was found to catalyze the dehydration of ethanol to diethylether or ethene, a green approach for the integrated production of four important chemicals is herein presented. This is based on renewable ethanol as a reagent and a modular catalytic process.

Parametric Study of Reactive Melt Infiltration

NASA Technical Reports Server (NTRS)

Nelson, Emily S.; Colella, Phillip

2000-01-01

Reactive melt infiltration is viewed as a promising means of achieving near-net shape manufacturing with quick processing time and at low cost. Since the reactants and products are, in general, of varying density, overall conservation of mass dictates that there is a force related to chemical conversion which can directly influence infiltration behavior. In effect, the driving pressure forces may compete with the forces from chemical conversion, affecting the advancement of the front. We have developed a two-dimensional numerical code to examine these effects, using reaction-formed silicon carbide as a model system for this process. We have examined a range of initial porosities, pore radii, and reaction rates in order to investigate their effects on infiltration dynamics.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zamecnik, J. R.; Edwards, T. B.

The conversions of nitrite to nitrate, the destruction of glycolate, and the conversion of glycolate to formate and oxalate were modeled for the Nitric-Glycolic flowsheet using data from Chemical Process Cell (CPC) simulant runs conducted by SRNL from 2011 to 2015. The goal of this work was to develop empirical correlations for these variables versus measureable variables from the chemical process so that these quantities could be predicted a-priori from the sludge composition and measurable processing variables. The need for these predictions arises from the need to predict the REDuction/OXidation (REDOX) state of the glass from the Defense Waste Processingmore » Facility (DWPF) melter. This report summarizes the initial work on these correlations based on the aforementioned data. Further refinement of the models as additional data is collected is recommended.« less

Catalytic Conversion of Renewable Resources into Bulk and Fine Chemicals.

PubMed

de Vries, Johannes G

2016-12-01

Several strategies can be chosen to convert renewable resources into chemicals. In this account, I exemplify the route that starts with so-called platform chemicals; these are relatively simple chemicals that can be produced in high yield, directly from renewable resources, either via fermentation or via chemical routes. They can be converted into the existing bulk chemicals in a very efficient manner using multistep catalytic conversions. Two examples are given of the conversion of sugars into nylon intermediates. 5-Hydroxymethylfurfural (HMF) can be prepared in good yield from fructose. Two hydrogenation steps convert HMF into 1,6-hexanediol. Oppenauer oxidation converts this product into caprolactone, which in the past, has been converted into caprolactam in a large-scale industrial process by reaction with ammonia. An even more interesting platform chemical is levulinic acid (LA), which can be obtained directly from lignocellulose in good yield by treatment with dilute sulfuric acid at 200°C. Hydrogenation converts LA into gamma-valerolactone, which is ring-opened and esterified in a gas-phase process to a mixture of isomeric methyl pentenoates in excellent selectivity. In a remarkable selective palladium-catalysed isomerising methoxycarbonylation, this mixture is converted in to dimethyl adipate, which is finally hydrolysed to adipic acid. Overall selectivities of both processes are extremely high. The conversion of lignin into chemicals is a much more complicated task in view of the complex nature of lignin. It was discovered that breakage of the most prevalent β-O-4 bond in lignin occurs not only via the well-documented C3 pathway, but also via a C2 pathway, leading to the formation of highly reactive phenylacetaldehydes. These compounds went largely unnoticed as they immediately recondense on lignin. We have now found that it is possible to prevent this by converting these aldehydes in a tandem reaction, as they are formed. For this purpose, we have used three different methods: acetalisation, hydrogenation, and decarbonylation. These reactions were first established in the tandem reactions of model compounds, but subsequently, we were able to show that this works equally well on organosolv lignin and even on lignocellulose. © 2016 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

In situ magnetic resonance measurement of conversion, hydrodynamics and mass transfer during single- and two-phase flow in fixed-bed reactors.

PubMed

Gladden, L F; Alexander, P; Britton, M M; Mantle, M D; Sederman, A J; Yuen, E H L

2003-01-01

In recent years there has been increasing interest in applying magnetic resonance (MR) techniques in areas of engineering and chemical technology. The science that underpins many of these applications is the physics and chemistry of transport and reaction processes in porous materials. Key to the exploitation of MR methods will be our ability to demonstrate that MR yields information that cannot be obtained using conventional measurement techniques in engineering research. This article describes two case studies that highlight the power of MR to give new insights to chemical engineers. First, we demonstrate the application of MR techniques to explore both mass transfer and chemical conversion in situ within a fixed bed of catalyst, and we then use these data to identify the rate-controlling step of the chemical conversion. Second, we implement a rapid imaging technique to study the stability of the gas-liquid distribution in the low- and high-interaction two-phase flow regimes in a trickle-bed reactor.

The Quest for Value-Added Products from Carbon Dioxide and Water in a Dielectric Barrier Discharge: A Chemical Kinetics Study.

PubMed

Snoeckx, Ramses; Ozkan, Alp; Reniers, Francois; Bogaerts, Annemie

2017-01-20

Recycling of carbon dioxide by its conversion into value-added products has gained significant interest owing to the role it can play for use in an anthropogenic carbon cycle. The combined conversion with H 2 O could even mimic the natural photosynthesis process. An interesting gas conversion technique currently being considered in the field of CO 2 conversion is plasma technology. To investigate whether it is also promising for this combined conversion, we performed a series of experiments and developed a chemical kinetics plasma chemistry model for a deeper understanding of the process. The main products formed were the syngas components CO and H 2 , as well as O 2 and H 2 O 2 , whereas methanol formation was only observed in the parts-per-billion to parts-per-million range. The syngas ratio, on the other hand, could easily be controlled by varying both the water content and/or energy input. On the basis of the model, which was validated with experimental results, a chemical kinetics analysis was performed, which allowed the construction and investigation of the different pathways leading to the observed experimental results and which helped to clarify these results. This approach allowed us to evaluate this technology on the basis of its underlying chemistry and to propose solutions on how to further improve the formation of value-added products by using plasma technology. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enzymatic production of ethanol from cellulose using soluble cellulose acetate as an intermediate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Downing, K.M.; Ho, C.S.; Zabriskie, D.W.

1987-01-01

A two-stage process for the enzymatic conversion of cellulose to ethanol is proposed as an alternative to currently incomplete and relatively slow enzymatic conversion processes employing natural insoluble cellulose. This alternative approach is designed to promote faster and more complete conversion of cellulose to fermentable sugars through the use of a homogeneous enzymatic hydrolysis reaction. Cellulose is chemically dissolved in the first stage to form water-soluble cellulose acetate (WSCA). The WSCA is then converted to ethanol in a simultaneous saccharification-fermentation with Pestalotiopsis westerdijkii enzymes (containing cellulolytic and acetyl esterase components) and yeast.

Thermal behavior in the cracking reaction zone of scramjet cooling channels at different channel aspect ratios

NASA Astrophysics Data System (ADS)

Zhang, Silong; Feng, Yu; Jiang, Yuguang; Qin, Jiang; Bao, Wen; Han, Jiecai; Haidn, Oskar J.

2016-10-01

To study the thermal behavior in the cracking reaction zone of regeneratively cooled scramjet cooling channels at different aspect ratios, 3-D model of fuel flow in terms of the fuel's real properties and cracking reaction is built and validated through experiments. The whole cooling channel is divided into non-cracking and cracking reaction zones. Only the cracking reaction zone is studied in this article. The simulation results indicate that the fuel conversion presents a similar distribution with temperature because the fuel conversion in scramjet cooling channels is co-decided by the temperature and velocity but the temperature plays the dominate role. For the cases given in this paper, increasing the channel aspect ratio will increase the pressure drop and it is not beneficial for reducing the wall temperature because of the much severer thermal stratification, larger conversion non-uniformity, the corresponding M-shape velocity profile which will cause local heat transfer deterioration and the decreased chemical heat absorption. And the decreased chemical heat absorption caused by stronger temperature and conversion non-uniformities is bad for the utilization of chemical heat sink, chemical recuperation process and the ignition performance.

Direct Conversion of Methane to Value-Added Chemicals over Heterogeneous Catalysts: Challenges and Prospects.

PubMed

Schwach, Pierre; Pan, Xiulian; Bao, Xinhe

2017-07-12

The quest for an efficient process to convert methane efficiently to fuels and high value-added chemicals such as olefins and aromatics is motivated by their increasing demands and recently discovered large reserves and resources of methane. Direct conversion to these chemicals can be realized either oxidatively via oxidative coupling of methane (OCM) or nonoxidatively via methane dehydroaromatization (MDA), which have been under intensive investigation for decades. While industrial applications are still limited by their low yield (selectivity) and stability issues, innovations in new catalysts and concepts are needed. The newly emerging strategy using iron single sites to catalyze methane conversion to olefins, aromatics, and hydrogen (MTOAH) attracted much attention when it was reported. Because the challenge lies in controlled dehydrogenation of the highly stable CH 4 and selective C-C coupling, we focus mainly on the fundamentals of C-H activation and analyze the reaction pathways toward selective routes of OCM, MDA, and MTOAH. With this, we intend to provide some insights into their reaction mechanisms and implications for future development of highly selective catalysts for direct conversion of methane to high value-added chemicals.

SIMULATION OF ECOLOGICALLY CONSCIOUS CHEMICAL PROCESSES: FUGITIVE EMISSIONS VERSUS OPERATING CONDITIONS

EPA Science Inventory

Catalytic reforming is an important refinery process for the conversion of low-octane naphtha (mostly paraffins) into high-octane motor fuels (isoparaffins, naphthenes and aromatics), light gases and hydrogen. In this study the catalytic reforming process is analyzed under differ...

Recent advances on conversion and co-production of acetone-butanol-ethanol into high value-added bioproducts.

PubMed

Xin, Fengxue; Dong, Weiliang; Jiang, Yujia; Ma, Jiangfeng; Zhang, Wenming; Wu, Hao; Zhang, Min; Jiang, Min

2018-06-01

Butanol is an important bulk chemical and has been regarded as an advanced biofuel. Large-scale production of butanol has been applied for more than 100 years, but its production through acetone-butanol-ethanol (ABE) fermentation process by solventogenic Clostridium species is still not economically viable due to the low butanol titer and yield caused by the toxicity of butanol and a by-product, such as acetone. Renewed interest in biobutanol as a biofuel has spurred technological advances to strain modification and fermentation process design. Especially, with the development of interdisciplinary processes, the sole product or even the mixture of ABE produced through ABE fermentation process can be further used as platform chemicals for high value added product production through enzymatic or chemical catalysis. This review aims to comprehensively summarize the most recent advances on the conversion of acetone, butanol and ABE mixture into various products, such as isopropanol, butyl-butyrate and higher-molecular mass alkanes. Additionally, co-production of other value added products with ABE was also discussed.

Bioconversion of lignocellulosic biomass to xylitol: An overview.

PubMed

Venkateswar Rao, Linga; Goli, Jyosthna Khanna; Gentela, Jahnavi; Koti, Sravanthi

2016-08-01

Lignocellulosic wastes include agricultural and forest residues which are most promising alternative energy sources and serve as potential low cost raw materials that can be exploited to produce xylitol. The strong physical and chemical construction of lignocelluloses is a major constraint for the recovery of xylose. The large scale production of xylitol is attained by nickel catalyzed chemical process that is based on xylose hydrogenation, that requires purified xylose as raw substrate and the process requires high temperature and pressure that remains to be cost intensive and energy consuming. Therefore, there is a necessity to develop an integrated process for biotechnological conversion of lignocelluloses to xylitol and make the process economical. The present review confers about the pretreatment strategies that facilitate cellulose and hemicellulose acquiescent for hydrolysis. There is also an emphasis on various detoxification and fermentation methodologies including genetic engineering strategies for the efficient conversion of xylose to xylitol. Copyright © 2016 Elsevier Ltd. All rights reserved.

A thermochemical-biochemical hybrid processing of lignocellulosic biomass for producing fuels and chemicals.

PubMed

Shen, Yanwen; Jarboe, Laura; Brown, Robert; Wen, Zhiyou

2015-12-01

Thermochemical-biological hybrid processing uses thermochemical decomposition of lignocellulosic biomass to produce a variety of intermediate compounds that can be converted into fuels and chemicals through microbial fermentation. It represents a unique opportunity for biomass conversion as it mitigates some of the deficiencies of conventional biochemical (pretreatment-hydrolysis-fermentation) and thermochemical (pyrolysis or gasification) processing. Thermochemical-biological hybrid processing includes two pathways: (i) pyrolysis/pyrolytic substrate fermentation, and (ii) gasification/syngas fermentation. This paper provides a comprehensive review of these two hybrid processing pathways, including the characteristics of fermentative substrates produced in the thermochemical stage and microbial utilization of these compounds in the fermentation stage. The current challenges of these two biomass conversion pathways include toxicity of the crude pyrolytic substrates, the inhibition of raw syngas contaminants, and the mass-transfer limitations in syngas fermentation. Possible approaches for mitigating substrate toxicities are discussed. The review also provides a summary of the current efforts to commercialize hybrid processing. Copyright © 2015 Elsevier Inc. All rights reserved.

Attrition-enhanced sulfur capture by limestone particles in fluidized beds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saastamoinen, J.J.; Shimizu, T.

2007-02-14

Sulfur capture by limestone particles in fluidized beds is a well-established technology. The underlying chemical and physical phenomena of the process have been extensively studied and modeled. However, most of the studies have been focused on the relatively brief initial stage of the process, which extends from a few minutes to hours, yet the residence time of the particles in the boiler is much longer. Following the initial stage, a dense product layer will be formed on the particle surface, which decreases the rate of sulfur capture and the degree of utilization of the sorbent. Attrition can enhance sulfur capturemore » by removing this layer. A particle model for sulfur capture has been incorporated with an attrition model. After the initial stage, the rate of sulfur capture stabilizes, so that attrition removes the surface at the same rate as diffusion and chemical reaction produces new product in a thin surface layer of a particle. An analytical solution for the conversion of particles for this regime is presented. The solution includes the effects of the attrition rate, diffusion, chemical kinetics, pressure, and SO{sub 2} concentration, relative to conversion-dependent diffusivity and the rate of chemical reaction. The particle model results in models that describe the conversion of limestone in both fly ash and bottom ash. These are incorporated with the residence time (or reactor) models to calculate the average conversion of the limestone in fly ash and bottom ash, as well as the efficiency of sulfur capture. Data from a large-scale pressurized fluidized bed are compared with the model results.« less

Thermo-Chemical Conversion of Microwave Activated Biomass Mixtures

NASA Astrophysics Data System (ADS)

Barmina, I.; Kolmickovs, A.; Valdmanis, R.; Vostrikovs, S.; Zake, M.

2018-05-01

Thermo-chemical conversion of microwave activated wheat straw mixtures with wood or peat pellets is studied experimentally with the aim to provide more effective application of wheat straw for heat energy production. Microwave pre-processing of straw pellets is used to provide a partial decomposition of the main constituents of straw and to activate the thermo-chemical conversion of wheat straw mixtures with wood or peat pellets. The experimental study includes complex measurements of the elemental composition of biomass pellets (wheat straw, wood, peat), DTG analysis of their thermal degradation, FTIR analysis of the composition of combustible volatiles entering the combustor, the flame temperature, the heat output of the device and composition of the products by comparing these characteristics for mixtures with unprocessed and mw pre-treated straw pellets. The results of experimental study confirm that mw pre-processing of straw activates the thermal decomposition of mixtures providing enhanced formation of combustible volatiles. This leads to improvement of the combustion conditions in the flame reaction zone, completing thus the combustion of volatiles, increasing the flame temperature, the heat output from the device, the produced heat energy per mass of burned mixture and decreasing at the same time the mass fraction of unburned volatiles in the products.

Ge/Si Ratios Record the Impact of Forest Conversion to Cropland on Soil Chemical Weathering Processes and Solutes Export to Rivers

NASA Astrophysics Data System (ADS)

Ameijeiras-Marino, Y.; Opfergelt, S.; Derry, L. A.; Robinet, J.; Delmelle, P.

2016-12-01

Soil weathering processes influence solute fluxes to rivers, playing a major role in global biogeochemical cycles. Land use change such as forest conversion to cropland enhances soil erosion, which mobilizes solutes and exposes new mineral surfaces to weathering processes, changing soil weathering degree. However, the impact of forest conversion to cropland on soil weathering degree and solute fluxes exported from soils to rivers remain poorly quantified. This study assesses the soil weathering degree and uses a geochemical tracer of weathering, Ge/Si ratio, to provide new insights on the impact of soil weathering processes under anthropogenic forcing on the transfer of solutes to rivers. A subtropical site was studied in Rio Grande do Sul (Brazil). This area is characterized by mean annual rainfall of 1800 mm, with strong rain events mobilizing high sediment load. A forested catchment is considered as the reference and compared to a catchment cultivated for the past 100 years (similar lithology and climate). Bedrock, soil, soil pore water and stream water (during base flow and rain events) samples were analysed for their chemical and mineralogical compositions and Ge/Si ratios (combined isotope dilution, HR-ICP-MS and hydride generation). Chemical and mineralogical analyses highlight that forest conversion to cropland decreases the soil weathering degree on steep slopes. Ge/Si ratios (μmol/mol) are comparable in bulk soils between the forested (2.33 ± 0.50) and the cultivated catchment (2.61 ± 0.62), but differ in soil pore waters between forest (0.47 ± 0.16) and culture (0.73 ± 0.15) indicating differences on soil weathering processes. The response of Ge/Si ratios in stream waters to a rain event differs between forest and culture, highlighting a larger contribution from soil pore waters to stream waters under culture. Altogether, our data support that land use history has an impact on the present day soil weathering processes and on the solute export to rivers.

Chemical recycling of scrap composites

NASA Technical Reports Server (NTRS)

Allred, Ronald E.; Salas, Richard M.

1994-01-01

There are no well-developed technologies for recycling composite materials other than grinding to produce fillers. New approaches are needed to reclaim these valuable resources. Chemical or tertiary recycling, conversion of polymers into low molecular weight hydrocarbons for reuse as chemicals or fuels, is emerging as the most practical means for obtaining value from waste plastics and composites. Adherent Technologies is exploring a low-temperature catalytic process for recycling plastics and composites. Laboratory results show that all types of plastics, thermosets as well as thermoplastics, can be converted in high yields to valuable hydrocarbon products. This novel catalytic process runs at 200 C, conversion times are rapid, the process is closed and, thus, nonpolluting, and no highly toxic gas or liquid products have been observed so no negative environmental impact will result from its implementation. Tests on reclamation of composite materials show that epoxy, imide, and engineering thermoplastic matrices can be converted to low molecular weight hydrocarbons leaving behind the reinforcing fibers for reuse as composite reinforcements in secondary, lower-performance applications. Chemical recycling is also a means to dispose of sensitive or classified organic materials without incineration and provides a means to eliminate or reduce mixed hazardous wastes containing organic materials.

Anaerobic Digestion.

PubMed

Liebetrau, Jan; Sträuber, Heike; Kretzschmar, Jörg; Denysenko, Velina; Nelles, Michael

2017-04-09

The term anaerobic digestion usually refers to the microbial conversion of organic material to biogas, which mainly consists of methane and carbon dioxide. The technical application of the naturally-occurring process is used to provide a renewable energy carrier and - as the substrate is often waste material - to reduce the organic matter content of the substrate prior to disposal.Applications can be found in sewage sludge treatment, the treatment of industrial and municipal solid wastes and wastewaters (including landfill gas utilization), and the conversion of agricultural residues and energy crops.For biorefinery concepts, the anaerobic digestion (AD) process is, on the one hand, an option to treat organic residues from other production processes. Concomitant effects are the reduction of organic carbon within the treated substance, the conversion of nitrogen and sulfur components, and the production of an energy-rich gas - the biogas. On the other hand, the multistep conversion of complex organic material offers the possibility of interrupting the conversion chain and locking out intermediates for utilization as basic material within the chemical industry.

Surface pre-treatment of aluminium by cleaning, chemical ething and conversion coating

NASA Astrophysics Data System (ADS)

Zaki, Mohammad Hafizudden Mohd; Mohd, Yusairie; Isa, Nik Norziehana Che

2017-12-01

Surface pre-treatment is one of the critical treatments for surface modification of aluminium (Al). In this study, pre-treatment of Al surface involved three stages; (1) cleaning (polishing and degreasing), (2) chemical etching (alkaline and acid) and (3) conversion coating (ie: zincate treatment). Cleaning process of Al was conducted by polishing and degreasing with acetone while etching process was done by immersion in 1.25 M NaOH solution (i.e: alkaline etching) followed with acid etching using 8 M HNO3 solution. The zincate treatment was conducted via electroless coating method by immersion of Al into a bath solution containing 0.5 M Zn(NO3)2, 0.1 M HNO3 and 0.2 M NaBH4 (reducing agent) for one hour. Different temperatures (ie: 25 °C, 50 °C, 75 °C, 90 °C) of bath solutions at pH 4 were used to investigate the effect of temperature on zincate treatment. Surface morphology and chemical composition of the pre-treated Al were characterized using Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersion X-ray analysis (EDX), respectively. The results showed that oxide layer on Al surface decreased after chemical etching process. Temperature of zincate solution has significantly affected the conversion coating process of aluminium. It was found that zinc oxide (ZnO) and zinc borate (ZnO.B2O3) were dominantly formed after zincate treatment at high temperature (ie:90 °C) with curved blade-like structure and composition of Zn, B and O with 13.70 wt.%, 3.52 wt.% and 54.39 wt.%, respectively. However, zincate treatment at low temperature (ie:<50 °C) has produced low metallic Zn.

Hydrothermal Gasification for Waste to Energy

NASA Astrophysics Data System (ADS)

Epps, Brenden; Laser, Mark; Choo, Yeunun

2014-11-01

Hydrothermal gasification is a promising technology for harvesting energy from waste streams. Applications range from straightforward waste-to-energy conversion (e.g. municipal waste processing, industrial waste processing), to water purification (e.g. oil spill cleanup, wastewater treatment), to biofuel energy systems (e.g. using algae as feedstock). Products of the gasification process are electricity, bottled syngas (H2 + CO), sequestered CO2, clean water, and inorganic solids; further chemical reactions can be used to create biofuels such as ethanol and biodiesel. We present a comparison of gasification system architectures, focusing on efficiency and economic performance metrics. Various system architectures are modeled computationally, using a model developed by the coauthors. The physical model tracks the mass of each chemical species, as well as energy conversions and transfers throughout the gasification process. The generic system model includes the feedstock, gasification reactor, heat recovery system, pressure reducing mechanical expanders, and electricity generation system. Sensitivity analysis of system performance to various process parameters is presented. A discussion of the key technological barriers and necessary innovations is also presented.

Catalytic Deoxydehydration of Carbohydrates and Polyols to Chemicals and Fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nicholas, Kenneth M.

As the world's fossil fuel resources are being depleted and their costs increase, there is an urgent need to discover and develop new processes for the conversion of renewable, biomass resources into fuels and chemical feedstocks. Research and development in this area have been given high priority by both governmental agencies and industry. To increase the energy content and decrease the boiling points of biomass-derived carbohydrates and polyols to the useful liquid range it is necessary to chemically remove water (dehydrate) and, preferably, oxygen (deoxygenate/reduce). The poly-hydroxylic nature of carbohydrates is attractive for their use as functionalized chemical building blocks,more » but it presents a daunting challenge for their selective conversion to single product chemicals or fuels. The long term, practical objective of this project is to develop catalytic processes for the deoxydehydration (DODH) of biomass-derived carbohydrates and polyols to produce unsaturated alcohols and hydrocarbons of value as chemical feedstocks and fuels; DODH: polyol + reductant --(LMOx catalyst)--> unsaturate + oxidized reductant + H2O. Limited prior studies have established the viability of the DODH process with expensive phosphine reductants and rhenium-catalysts. Initial studies in the PI's laboratory have now demonstrated: 1) the moderately efficient conversion of glycols to olefins by the economical sulfite salts is catalyzed by MeReO3 and Z+ReO4-; 2) effective phosphine-based catalytic DODH of representative glycols to olefins by cheap LMoO2 complexes; and 3) computational studies (with K. Houk, UCLA) have identified several Mo-, W-, and V-oxo complexes that are likely to catalyze glycol DODH. Seeking practically useful DODH reactions of complex polyols and new understanding of the reactivity of polyoxo-metal species with biomass-oxygenates we will employ a two-pronged approach: 1) investigate experimentally the reactivity, both stoichiometric and catalytic, of polyoxo-complexes and practical reductants with representative polyols to establish structure/reactivity relationships and reaction mechanisms; and b) carry out parallel computational studies of these reactions and their mechanisms- both analytical and predictive. Our prioritized action plan is: (1) to optimize the catalytic efficiency, assess the substrate scope/selectivity, and address key mechanistic aspects of Re-catalyzed, sulfite-driven DODH reactions; (2) use the findings from (1), together with computational predictions, to discover new, effective non-precious metal catalysts for sulfite-driven DODH reactions; and 3) to initiate exploratory studies of CO- and H2-driven DODH. Successful execution of this research project will: 1) provide practical chemical processes for the conversion of biomass into useful chemicals and fuels: 2) bring fundamental new understanding of chemical reactions involving metal-oxo catalysts; and 3) provide educational and technical training of future energy scientists.« less

Small Scale Gasification Application and Perspectives in Circular Economy

NASA Astrophysics Data System (ADS)

Klavins, Maris; Bisters, Valdis; Burlakovs, Juris

2018-06-01

Gasification is the process converting solid fuels as coal and organic plant matter, or biomass into combustible gas, called syngas. Gasification is a thermal conversion process using carbonaceous fuel, and it differs substantially from other thermal processes such as incineration or pyrolysis. The process can be used with virtually any carbonaceous fuel. It is an endothermic thermal conversion process, with partial oxidation being the dominant feature. Gasification converts various feedstock including waste to a syngas. Instead of producing only heat and electricity, synthesis gas produced by gasification may be transformed into commercial products with higher value as transport fuels, fertilizers, chemicals and even to substitute natural gas. Thermo-chemical conversion of biomass and solid municipal waste is developing as a tool to promote the idea of energy system without fossil fuels to a reality. In municipal solid waste management, gasification does not compete with recycling, moreover it enhances recycling programs. Pre-processing and after-processing must increase the amount of recyclables in the circular economy. Additionally, end of life plastics can serve as an energy feedstock for gasification as otherwise it cannot be sorted out and recycled. There is great potential for application of gasification technology within the biomass waste and solid waste management sector. Industrial self-consumption in the mode of combined heat and power can contribute to sustainable economic development within a circular economy.

Sources of biomass feedstock variability and the potential impact on biofuels production

DOE PAGES

Williams, C. Luke; Westover, Tyler L.; Emerson, Rachel M.; ...

2015-11-23

In this study, terrestrial lignocellulosic biomass has the potential to be a carbon neutral and domestic source of fuels and chemicals. However, the innate variability of biomass resources, such as herbaceous and woody materials, and the inconsistency within a single resource due to disparate growth and harvesting conditions, presents challenges for downstream processes which often require materials that are physically and chemically consistent. Intrinsic biomass characteristics, including moisture content, carbohydrate and ash compositions, bulk density, and particle size/shape distributions are highly variable and can impact the economics of transforming biomass into value-added products. For instance, ash content increases by anmore » order of magnitude between woody and herbaceous feedstocks (from ~0.5 to 5 %, respectively) while lignin content drops by a factor of two (from ~30 to 15 %, respectively). This increase in ash and reduction in lignin leads to biofuel conversion consequences, such as reduced pyrolysis oil yields for herbaceous products as compared to woody material. In this review, the sources of variability for key biomass characteristics are presented for multiple types of biomass. Additionally, this review investigates the major impacts of the variability in biomass composition on four conversion processes: fermentation, hydrothermal liquefaction, pyrolysis, and direct combustion. Finally, future research processes aimed at reducing the detrimental impacts of biomass variability on conversion to fuels and chemicals are proposed.« less

Ionic Liquids in Biomass Processing

NASA Astrophysics Data System (ADS)

Tan, Suzie Su Yin; Macfarlane, Douglas R.

Ionic liquids have been studied for their special solvent properties in a wide range of processes, including reactions involving carbohydrates such as cellulose and glucose. Biomass is a widely available and renewable resource that is likely to become an economically viable source of starting materials for chemical and fuel production, especially with the price of petroleum set to increase as supplies are diminished. Biopolymers such as cellulose, hemicellulose and lignin may be converted to useful products, either by direct functionalisation of the polymers or depolymerisation to monomers, followed by microbial or chemical conversion to useful chemicals. Major barriers to the effective conversion of biomass currently include the high crystallinity of cellulose, high reactivity of carbohydrates and lignin, insolubility of cellulose in conventional solvents, as well as heterogeneity in the native lignocellulosic materials and in lignin itself. This combination of factors often results in highly heterogeneous depolymerisation products, which make efficient separation difficult. Thus the extraction, depolymerisation and conversion of biopolymers will require novel reaction systems in order to be both economically attractive and environmentally benign. The solubility of biopolymers in ionic liquids is a major advantage of their use, allowing homogeneous reaction conditions, and this has stimulated a growing research effort in this field. This review examines current research involving the use of ionic liquids in biomass reactions, with perspectives on how it relates to green chemistry, economic viability, and conventional biomass processes.

The Preparation, Characterization and Formation Mechanism of a Calcium Phosphate Conversion Coating on Magnesium Alloy AZ91D.

PubMed

Liu, Dong; Li, Yanyan; Zhou, Yong; Ding, Yigang

2018-05-28

The poor corrosion resistance of magnesium alloys is one of the main obstacles preventing their widespread usage. Due to the advantages of lower cost and simplicity in operation, chemical conversion coating has drawn considerable attention for its improvement of the corrosion resistance of magnesium alloys. In this study, a calcium phosphate coating was prepared on magnesium alloy AZ91D by chemical conversion. For the calcium phosphate coating, the effect of processing parameters on the microstructure and corrosion resistance was studied by scanning electron microscope (SEM) and electrochemical methods, and the coating composition was characterized by X-ray diffraction (XRD). The calcium phosphate coating was mainly composed of CaHPO₄·2H₂O (DCPD), with fewer cracks and pores. The coating with the leaf-like microstructure provided great corrosion resistance to the AZ91D substrate, and was obtained under the following conditions: 20 min, ambient temperature, and no stirring. At the same time, the role of NH₄H₂PO₄ as the coating-forming agent and the acidifying agent in the conversion process was realized, and the formation mechanism of DCPD was discussed in detail in this work.

B827 Chemical Synthhesis Project - Industrial Control System Integration - Statement of Work & Specification with Attachments 1-14

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wade, F. E.

The Chemical Synthesis Pilot Process at the Lawrence Livermore National Laboratory (LLNL) Site 300 827 Complex will be used to synthesize small quantities of material to support research and development. The project will modernize and increase current capabilities for chemical synthesis at LLNL. The primary objective of this project is the conversion of a non-automated hands-on process to a remoteoperation process, while providing enhanced batch process step control, stored recipe-specific parameter sets, process variable visibility, monitoring, alarm and warning handling, and comprehensive batch record data logging. This Statement of Work and Specification provides the industrial-grade process control requirements for themore » chemical synthesis batching control system, hereafter referred to as the “Control System” to be delivered by the System Integrator.« less

Process for the conversion of and aqueous biomass hydrolyzate into fuels or chemicals by the selective removal of fermentation inhibitors

DOEpatents

Hames, Bonnie R.; Sluiter, Amie D.; Hayward, Tammy K.; Nagle, Nicholas J.

2004-05-18

A process of making a fuel or chemical from a biomass hydrolyzate is provided which comprises the steps of providing a biomass hydrolyzate, adjusting the pH of the hydrolyzate, contacting a metal oxide having an affinity for guaiacyl or syringyl functional groups, or both and the hydrolyzate for a time sufficient to form an adsorption complex; removing the complex wherein a sugar fraction is provided, and converting the sugar fraction to fuels or chemicals using a microorganism.

Electrobiorefineries: Unlocking the Synergy of Electrochemical and Microbial Conversions.

PubMed

Harnisch, Falk; Urban, Carolin

2017-12-13

An integrated biobased economy urges an alliance of the two realms of "chemical production" and "electric power". The concept of electrobiorefineries provides a blueprint for such an alliance. Joining the forces of microbial and electrochemical conversions in electrobiorefineries allows interfacing the production, storage, and exploitation of electricity as well as biobased chemicals. Electrobiorefineries are a technological evolution of biorefineries by the addition of (bio)electrochemical transformations. This interfacing of microbial and electrochemical conversions will result in synergies affecting the entire process line, like enlarging the product portfolio, increasing the productivity, or exploiting new feedstock. A special emphasis is given to the utilization of oxidative and reductive electroorganic reactions of microbially produced intermediates that may serve as privileged building blocks. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reduced product yield in chemical processes by second law effects

NASA Technical Reports Server (NTRS)

England, C.; Funk, J. E.

1980-01-01

An analysis of second law effects in chemical processes, where product yield is explicitly related to the individual irreversibilities within the process to indicate a maximum theoretical yield, is presented. Examples are given that indicate differences between first and second law approaches toward process efficiency and process yield. This analysis also expresses production capacity in terms of the heating value of a product. As a result, it is particularly convenient in analyzing fuel conversion plants and their potential for improvement. Relationships are also given for the effects of irreversibilities on requirements for process heat and for feedstocks.

Thermochemical conversion of microalgal biomass into biofuels: a review.

PubMed

Chen, Wei-Hsin; Lin, Bo-Jhih; Huang, Ming-Yueh; Chang, Jo-Shu

2015-05-01

Following first-generation and second-generation biofuels produced from food and non-food crops, respectively, algal biomass has become an important feedstock for the production of third-generation biofuels. Microalgal biomass is characterized by rapid growth and high carbon fixing efficiency when they grow. On account of potential of mass production and greenhouse gas uptake, microalgae are promising feedstocks for biofuels development. Thermochemical conversion is an effective process for biofuel production from biomass. The technology mainly includes torrefaction, liquefaction, pyrolysis, and gasification. Through these conversion technologies, solid, liquid, and gaseous biofuels are produced from microalgae for heat and power generation. The liquid bio-oils can further be upgraded for chemicals, while the synthesis gas can be synthesized into liquid fuels. This paper aims to provide a state-of-the-art review of the thermochemical conversion technologies of microalgal biomass into fuels. Detailed conversion processes and their outcome are also addressed. Copyright © 2014 Elsevier Ltd. All rights reserved.

CHEMICAL ENGINEERING DIVISION SUMMARY REPORT, OCTOBER, NOVEMBER, DECEMBER 1960

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1961-03-01

Chemical-metallurgical processing studies were made of pyrometallurgical development snd research, and fuel processing facilities for EBR-II. Fuel-cycle applications of fluidization and volatility techniques included laboratory investigations of fluoride volatility processes, engineeringscale development, and conversion of UF/sub 6/ to UO/sub 2/. Reactor safety studies consisted of metal oxidation and ignition kinetics, and metal-water reactions. Reactor chemistry investigations were conducted to determine nuclear constants and suitable reactor decontamination methods. Routine operations are summarized for the high-level gammairradiation facillty and waste processing. (B.O.G.)

New Laboratory Course for Senior-Level Chemical Engineering Students

ERIC Educational Resources Information Center

Aronson, Mark T.; Deitcher, Robert W.; Xi, Yuanzhou; Davis, Robert J.

2009-01-01

A new laboratory course has been developed at the University of Virginia for senior- level chemical engineering students. The new course is based on three 4-week long experiments in bioprocess engineering, energy conversion and catalysis, and polymer synthesis and characterization. The emphasis is on the integration of process steps and the…

Twelve testable hypotheses on the geobiology of weathering

Treesearch

S.L. Brantley; J.P. Megonigal; F.N. Scatena; Z. Balogh-Brunstad; R.T. Barnes; M.A. Bruns; P. van Cappelen; K. Dontsova; H.E. Hartnett; A.S. Hartshorn; A. Heimsath; E. Herndon; L. Jin; C.K. Keller; J.R. Leake; W.H. McDowell; F.C. Meinzer; T.J. Mozdzer; S. Petsch; J. Pett-Ridge; K.S. Pretziger; P.A. Raymond; C.S. Riebe; K. Shumaker; A. Sutton-Grier; R. Walter; K. Yoo

2011-01-01

Critical Zone (CZ) research investigates the chemical, physical, and biological processes that modulate the Earth's surface. Here, we advance 12 hypotheses that must be tested to improve our understanding of the CZ: (1) Solar-to-chemical conversion of energy by plants regulates flows of carbon, water, and nutrients through plant-microbe soil networks, thereby...

Selective production of chemicals from biomass pyrolysis over metal chlorides supported on zeolite.

PubMed

Leng, Shuai; Wang, Xinde; Cai, Qiuxia; Ma, Fengyun; Liu, Yue'e; Wang, Jianguo

2013-12-01

Direct biomass conversion into chemicals remains a great challenge because of the complexity of the compounds; hence, this process has attracted less attention than conversion into fuel. In this study, we propose a simple one-step method for converting bagasse into furfural (FF) and acetic acid (AC). In this method, bagasse pyrolysis over ZnCl2/HZSM-5 achieved a high FF and AC yield (58.10%) and a 1.01 FF/AC ratio, but a very low yield of medium-boiling point components. However, bagasse pyrolysis using HZSM-5 alone or ZnCl2 alone still remained large amounts of medium-boiling point components or high-boiling point components. The synergistic effect of HZSM-5 and ZnCl2, which combines pyrolysis, zeolite cracking, and Lewis acid-selective catalysis results in highly efficient bagasse conversion into FF and AC. Therefore, our study provides a novel, simple method for directly converting biomass into high-yield useful chemical. Copyright © 2013 Elsevier Ltd. All rights reserved.

75 FR 4402 - Notice of National Conversation on Public Health and Chemical Exposures Leadership Council...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-27

... National Conversation on Public Health and Chemical Exposures Leadership Council Conference Call Time and... the second meeting of the National Conversation on Public Health and Chemical Exposures Leadership... Leadership Council provides overall guidance to the National Conversation project and will be responsible for...

Plasma for environment

NASA Astrophysics Data System (ADS)

Van Oost, G.

2017-12-01

Human activity is associated with the permanent emergence of a very wide range of waste streams. The most widely used treatment of waste is thermal processing such as incineration. An alternative environmentally friendly process is based on thermal plasma technology which is a very flexible tool because it allows to operate in a wide temperature range with almost any chemical composition of waste and chemicals needed for processing this waste. It allows the conversion of organic waste into energy or chemical substances as well as the destruction of toxic organic compounds in a scenario that for each specific type of waste can be considered optimal, both in terms of energy efficiency and environmental safety.

Deposition and Characterization of Thin Films on Metallic Substrates

NASA Technical Reports Server (NTRS)

Gatica, Jorge E.

2005-01-01

A CVD method was successfully developed to produce conversion coatings on aluminum alloys surfaces with reproducible results with a variety of precursors. A well defined protocol to prepare the precursor solutions formulated in a previous research was extended to other additives. It was demonstrated that solutions prepared following such a protocol could be used to systematically generate protective coatings onto aluminum surfaces. Experiments with a variety of formulations revealed that a refined deposition protocol yields reproducible conversion coatings of controlled composition. A preliminary correlation between solution formulations and successful precursors was derived. Coatings were tested for adhesion properties enhancement for commercial paints. A standard testing method was followed and clear trends were identified. Only one precursors was tested systematically. Anticipated work on other precursors should allow a better characterization of the effect of intermetallics on the production of conversion/protective coatings on metals and ceramics. The significance of this work was the practical demonstration that chemical vapor deposition (CVD) techniques can be used to systematically generate protective/conversion coating on non-ferrous surfaces. In order to become an effective approach to replace chromate-based pre- treatment processes, namely in the aerospace or automobile industry, the process parameters must be defined more precisely. Moreover, the feasibility of scale-up designs necessitates a more comprehensive characterization of the fluid flow, transport phenomena, and chemical kinetics interacting in the process. Kinetic characterization showed a significantly different effect of magnesium-based precursors when compared to iron-based precursors. Future work will concentrate on refining the process through computer simulations and further experimental studies on the effect of other transition metals to induce deposition of conversion/protective films on aluminum and other metallic substrates.

Magnesium carbide synthesis from methane and magnesium oxide - a potential methodology for natural gas conversion to premium fuels and chemicals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diaz, A.F.; Modestino, A.J.; Howard, J.B.

1995-12-31

Diversification of the raw materials base for manufacturing premium fuels and chemicals offers U.S. and international consumers economic and strategic benefits. Extensive reserves of natural gas in the world provide a valuable source of clean gaseous fuel and chemical feedstock. Assuming the availability of suitable conversion processes, natural gas offers the prospect of improving flexibility in liquid fuels and chemicals manufacture, and thus, the opportunity to complement, supplement, or displace petroleum-based production as economic and strategic considerations require. The composition of natural gas varies from reservoir to reservoir but the principal hydrocarbon constituent is always methane (CH{sub 4}). With itsmore » high hydrogen-to-carbon ratio, methane has the potential to produce hydrogen or hydrogen-rich products. However, methane is a very chemically stable molecule and, thus, is not readily transformed to other molecules or easily reformed to its elements (H{sub 2} and carbon). In many cases, further research is needed to augment selectivity to desired product(s), increase single-pass conversions, or improve economics (e.g. there have been estimates of $50/bbl or more for liquid products) before the full potential of these methodologies can be realized on a commercial scale. With the trade-off between gas conversion and product selectivity, a major challenge common to many of these technologies is to simultaneously achieve high methane single-pass conversions and high selectivity to desired products. Based on the results of the scoping runs, there appears to be strong indications that a breakthrough has finally been achieved in that synthesis of magnesium carbides from MgO and methane in the arc discharge reactor has been demonstrated.« less

Comparison of oil refining and biodiesel production process between screw press and n-hexane techniques from beauty leaf feedstock

NASA Astrophysics Data System (ADS)

Bhuiya, M. M. K.; Rasul, M. G.; Khan, M. M. K.; Ashwath, N.

2016-07-01

The Beauty Leaf Tree (Callophylum inophyllum) is regarded as an alternative source of energy to produce 2nd generation biodiesel due to its potentiality as well as high oil yield content in the seed kernels. The treating process is indispensable during the biodiesel production process because it can augment the yield as well as quality of the product. Oil extracted from both mechanical screw press and solvent extraction using n-hexane was refined. Five replications each of 25 gm of crude oil for screw press and five replications each of 25 gm of crude oil for n-hexane were selected for refining as well as biodiesel conversion processes. The oil refining processes consists of degumming, neutralization as well as dewaxing. The degumming, neutralization and dewaxing processes were performed to remove all the gums (phosphorous-based compounds), free fatty acids, and waxes from the fresh crude oil before the biodiesel conversion process carried out, respectively. The results indicated that up to 73% and 81% of mass conversion efficiency of the refined oil in the screw press and n-hexane refining processes were obtained, respectively. It was also found that up to 88% and 90% of biodiesel were yielded in terms of mass conversion efficiency in the transesterification process for the screw press and n-hexane techniques, respectively. While the entire processes (refining and transesterification) were considered, the conversion of beauty leaf tree (BLT) refined oil into biodiesel was yielded up to 65% and 73% of mass conversion efficiency for the screw press and n-hexane techniques, respectively. Physico-chemical properties of crude and refined oil, and biodiesel were characterized according to the ASTM standards. Overall, BLT has the potential to contribute as an alternative energy source because of high mass conversion efficiency.

75 FR 52355 - Draft National Conversation on Public Health and Chemical Exposures Work Group Reports...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-25

... Conversation on Public Health and Chemical Exposures Work Group Reports; Opportunity for Public Comment AGENCY... Conversation on Public Health and Chemical Exposures is a collaborative initiative through which many... protecting the public's health from harmful chemical exposures. This notice announces the availability of...

Physico-Chemical Conversion of Lignocellulose: Inhibitor Effects and Detoxification Strategies: A Mini Review.

PubMed

Kim, Daehwan

2018-02-01

A pretreatment of lignocellulosic biomass to produce biofuels, polymers, and other chemicals plays a vital role in the biochemical conversion process toward disrupting the closely associated structures of the cellulose-hemicellulose-lignin molecules. Various pretreatment steps alter the chemical/physical structure of lignocellulosic materials by solubilizing hemicellulose and/or lignin, decreasing the particle sizes of substrate and the crystalline portions of cellulose, and increasing the surface area of biomass. These modifications enhance the hydrolysis of cellulose by increasing accessibilities of acids or enzymes onto the surface of cellulose. However, lignocellulose-derived byproducts, which can inhibit and/or deactivate enzyme and microbial biocatalysts, are formed, including furan derivatives, lignin-derived phenolics, and carboxylic acids. These generation of compounds during pretreatment with inhibitory effects can lead to negative effects on subsequent steps in sugar flat-form processes. A number of physico-chemical pretreatment methods such as steam explosion, ammonia fiber explosion (AFEX), and liquid hot water (LHW) have been suggested and developed for minimizing formation of inhibitory compounds and alleviating their effects on ethanol production processes. This work reviews the physico-chemical pretreatment methods used for various biomass sources, formation of lignocellulose-derived inhibitors, and their contributions to enzymatic hydrolysis and microbial activities. Furthermore, we provide an overview of the current strategies to alleviate inhibitory compounds present in the hydrolysates or slurries.

THE ENERGY CONVERSION APPARATUS IN PHOTOSYNTHESIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sauer, K.

1962-12-01

An analysis of outstanding problems still presenting difficulty with respect to understanding the quantumconversion process in photosynthesis is presented. Considerations of how some of these difficulties may be overcome are included. The dynamic process of energy conversion is considered in terms of photon absorption, electronic energy transfer, trapping in long-lived excited states, primary oxidants and reductants, and the electron transport chain leading to products representing stored chemical potential. The physical structure of the apparatus accomplishing this energy conversion is sought in the framework of the concept of the photosynthetic unit. The nature of this unit--its size, composition, arrangement and orientationmore » of components, internal electrical and polarizability properties, and assembly and aggregation in the chloroplast--and the problems related to its determination are essential considerations in the overall approach to the understanding of the mechanism of energy conversion. (auth)« less

Increasing the revenue from lignocellulosic biomass: Maximizing feedstock utilization

PubMed Central

Alonso, David Martin; Hakim, Sikander H.; Zhou, Shengfei; Won, Wangyun; Hosseinaei, Omid; Tao, Jingming; Garcia-Negron, Valerie; Motagamwala, Ali Hussain; Mellmer, Max A.; Huang, Kefeng; Houtman, Carl J.; Labbé, Nicole; Harper, David P.; Maravelias, Christos T.; Runge, Troy; Dumesic, James A.

2017-01-01

The production of renewable chemicals and biofuels must be cost- and performance- competitive with petroleum-derived equivalents to be widely accepted by markets and society. We propose a biomass conversion strategy that maximizes the conversion of lignocellulosic biomass (up to 80% of the biomass to useful products) into high-value products that can be commercialized, providing the opportunity for successful translation to an economically viable commercial process. Our fractionation method preserves the value of all three primary components: (i) cellulose, which is converted into dissolving pulp for fibers and chemicals production; (ii) hemicellulose, which is converted into furfural (a building block chemical); and (iii) lignin, which is converted into carbon products (carbon foam, fibers, or battery anodes), together producing revenues of more than $500 per dry metric ton of biomass. Once de-risked, our technology can be extended to produce other renewable chemicals and biofuels. PMID:28560350

Increasing the revenue from lignocellulosic biomass: Maximizing feedstock utilization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alonso, David Martin; Hakim, Sikander H.; Zhou, Shengfei

The production of renewable chemicals and biofuels must be cost- and performance- competitive with petroleum-derived equivalents to be widely accepted by markets and society. We propose a biomass conversion strategy that maximizes the conversion of lignocellulosic biomass (up to 80% of the biomass to useful products) into high-value products that can be commercialized, providing the opportunity for successful translation to an economically viable commercial process. Our fractionation method preserves the value of all three primary components: (i) cellulose, which is converted into dissolving pulp for fibers and chemicals production; (ii) hemicellulose, which is converted into furfural (a building block chemical);more » and (iii) lignin, which is converted into carbon products (carbon foam, fibers, or battery anodes), together producing revenues of more than $500 per dry metric ton of biomass. Once de-risked, our technology can be extended to produce other renewable chemicals and biofuels.« less

Increasing the revenue from lignocellulosic biomass: Maximizing feedstock utilization

DOE PAGES

Alonso, David Martin; Hakim, Sikander H.; Zhou, Shengfei; ...

2017-05-19

The production of renewable chemicals and biofuels must be cost- and performance- competitive with petroleum-derived equivalents to be widely accepted by markets and society. We propose a biomass conversion strategy that maximizes the conversion of lignocellulosic biomass (up to 80% of the biomass to useful products) into high-value products that can be commercialized, providing the opportunity for successful translation to an economically viable commercial process. Our fractionation method preserves the value of all three primary components: (i) cellulose, which is converted into dissolving pulp for fibers and chemicals production; (ii) hemicellulose, which is converted into furfural (a building block chemical);more » and (iii) lignin, which is converted into carbon products (carbon foam, fibers, or battery anodes), together producing revenues of more than $500 per dry metric ton of biomass. Once de-risked, our technology can be extended to produce other renewable chemicals and biofuels.« less

Biomass energy production. Citations from the International Aerospace Abstracts data base

NASA Technical Reports Server (NTRS)

Moore, P. W.

1980-01-01

These 210 citations from the international literature describe the production and/or utilization of most forms of biomass as a source of energy, fuel, food, and chemical intermediates or feedstocks. Biomass conversion by incineration, gasification, pyrolysis, hydrolysis, anaerobic digestion, or fermentation, as well as by catalytic, photosynthetic, chemosynthetic, and bio-electrochemical means are among the conversion processes considered. Discussions include biomass plantation and material productivity, transportation and equipment requirements, effects, comparisons of means and efficiencies of utilization and conversion, assessments of limitations, and evaluations of economic potential.

Sonochemistry: what potential for conversion of lignocellulosic biomass into platform chemicals?

PubMed

Chatel, Gregory; De Oliveira Vigier, Karine; Jérôme, François

2014-10-01

This Review focuses on the use of ultrasound to produce chemicals from lignocellulosic biomass. However, the question about the potential of sonochemistry for valorization/conversion of lignocellulosic biomass into added-value chemicals is rather conceptual. Until now, this technology has been mainly used for the production of low-value chemicals such as biodiesel or as simple method for pretreatment or extraction. According to preliminary studies reported in literature, access to added-value chemicals can be easily and sometimes solely obtained by the use of ultrasound. The design of sonochemical parameters offers many opportunities to develop new eco-friendly and efficient processes. The goal of this Review is to understand why the use of ultrasound is focused rather on pretreatment or extraction of lignocellulosic biomass rather than on the production of chemicals and to understand, through the reported examples, which directions need to be followed to favor strategies based on ultrasound-assisted production of chemicals from lignocellulosic biomass. We believe that ultrasound-assisted processes represent an innovative approach and will create a growing interest in academia but also in the industry in the near future. Based on the examples reported in the literature, we critically discuss how sonochemistry could offer new strategies and give rise to new results in lignocellulosic biomass valorization. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

One-Pot Conversion of Carbohydrates into Furan Derivatives via Furfural and 5-Hydroxylmethylfurfural as Intermediates.

PubMed

Liu, Bing; Zhang, Zehui

2016-08-23

Recently, there has been growing interest in the transformation of renewable biomass into value-added fuels and chemicals. The catalytic conversion of naturally abundant carbohydrates can generate two-important furan chemicals: 5-hydroxymethylfurfural (HMF) from C6 carbohydrates and furfural from C5 carbohydrates. Both HMF and furfural have received great interest as precursors in the synthesis of commodity chemicals and liquid fuels. In recent years, a trend has emerged to integrate sequential catalytic processes involving multistep reactions for the direct one-pot transformation of carbohydrates into the aimed fuels and chemicals. One-pot reactions have remarkably unique and environmentally friendly benefits, including the fact that isolation and purification of intermediate compounds can be avoided. Herein, the present article aims to review recent advances in the one-pot conversion of carbohydrates into furan derivatives via furfural and HMF as intermediates. Special attention will be paid to the catalytic systems, mechanistic insight, reaction pathways, and catalyst stability. It is expected that this review will guide researchers to develop effective catalytic systems for the one-pot transformation of carbohydrates into furan derivatives. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chemicals as the Sole Transformers of Cell Fate.

PubMed

Ebrahimi, Behnam

2016-05-30

Forced expression of lineage-specific transcription factors in somatic cells can result in the generation of different cell types in a process named direct reprogramming, bypassing the pluripotent state. However, the introduction of transgenes limits the therapeutic applications of the produced cells. Numerous small-molecules have been introduced in the field of stem cell biology capable of governing self-renewal, reprogramming, transdifferentiation and regeneration. These chemical compounds are versatile tools for cell fate conversion toward desired outcomes. Cell fate conversion using small-molecules alone (chemical reprogramming) has superiority over arduous traditional genetic techniques in several aspects. For instance, rapid, transient, and reversible effects in activation and inhibition of functions of specific proteins are of the profits of small-molecules. They are cost-effective, have a long half-life, diversity on structure and function, and allow for temporal and flexible regulation of signaling pathways. Additionally, their effects could be adjusted by fine-tuning concentrations and combinations of different small-molecules. Therefore, chemicals are powerful tools in cell fate conversion and study of stem cell and chemical biology in vitro and in vivo. Moreover, transgene-free and chemical-only transdifferentiation approaches provide alternative strategies for the generation of various cell types, disease modeling, drug screening, and regenerative medicine. The current review gives an overview of the recent findings concerning transdifferentiation by only small-molecules without the use of transgenes.

Use of mechanical refining to improve the production of low-cost sugars from lignocellulosic biomass.

PubMed

Park, Junyeong; Jones, Brandon; Koo, Bonwook; Chen, Xiaowen; Tucker, Melvin; Yu, Ju-Hyun; Pschorn, Thomas; Venditti, Richard; Park, Sunkyu

2016-01-01

Mechanical refining is widely used in the pulp and paper industry to enhance the end-use properties of products by creating external fibrillation and internal delamination. This technology can be directly applied to biochemical conversion processes. By implementing mechanical refining technology, biomass recalcitrance to enzyme hydrolysis can be overcome and carbohydrate conversion can be enhanced with commercially attractive levels of enzymes. In addition, chemical and thermal pretreatment severity can be reduced to achieve the same level of carbohydrate conversion, which reduces pretreatment cost and results in lower concentrations of inhibitors. Refining is versatile and a commercially proven technology that can be operated at process flows of ∼ 1500 dry tons per day of biomass. This paper reviews the utilization of mechanical refining in the pulp and paper industry and summarizes the recent development in applications for biochemical conversion, which potentially make an overall biorefinery process more economically viable. Copyright © 2015 Elsevier Ltd. All rights reserved.

PILOT PLANT STUDY OF CONVERSION OF COAL TO LOW SULFUR FUEL

EPA Science Inventory

The report gives results of a program to develop, on bench and pilot scales, operating conditions for the key step in the IGT process to desulfurize coal by thermal and chemical treatment. This process, to date, uses the 'sulfur-getter' concept. (A sulfur-getter is a material tha...

Advanced technology applications for second and third generation coal gasification systems. Appendix

NASA Technical Reports Server (NTRS)

Bradford, R.; Hyde, J. D.; Mead, C. W.

1980-01-01

Sixteen coal conversion processes are described and their projected goals listed. Tables show the reactants used, products derived, typical operating data, and properties of the feed coal. A history of the development of each process is included along with a drawing of the chemical reactor used.

Biochemical Conversion Processes of Lignocellulosic Biomass to Fuels and Chemicals - A Review.

PubMed

Brethauer, Simone; Studer, Michael H

2015-01-01

Lignocellulosic biomass - such as wood, agricultural residues or dedicated energy crops - is a promising renewable feedstock for production of fuels and chemicals that is available at large scale at low cost without direct competition for food usage. Its biochemical conversion in a sugar platform biorefinery includes three main unit operations that are illustrated in this review: the physico-chemical pretreatment of the biomass, the enzymatic hydrolysis of the carbohydrates to a fermentable sugar stream by cellulases and finally the fermentation of the sugars by suitable microorganisms to the target molecules. Special emphasis in this review is put on the technology, commercial status and future prospects of the production of second-generation fuel ethanol, as this process has received most research and development efforts so far. Despite significant advances, high enzyme costs are still a hurdle for large scale competitive lignocellulosic ethanol production. This could be overcome by a strategy termed 'consolidated bioprocessing' (CBP), where enzyme production, enzymatic hydrolysis and fermentation is integrated in one step - either by utilizing one genetically engineered superior microorganism or by creating an artificial co-culture. Insight is provided on both CBP strategies for the production of ethanol as well as of advanced fuels and commodity chemicals.

Mechanism of nuclear spin initiated para-H2 to ortho-H2 conversion.

PubMed

Buntkowsky, G; Walaszek, B; Adamczyk, A; Xu, Y; Limbach, H-H; Chaudret, B

2006-04-28

In this paper a quantitative explanation for a diamagnetic ortho/para H2 conversion is given. The description is based on the quantum-mechanical density matrix formalism originally developed by Alexander and Binsch for studies of exchange processes in NMR spectra. Only the nuclear spin system is treated quantum-mechanically. Employing the model of a three spin system, the reactions of the hydrogen gas with the catalysts are treated as a phenomenological rate process, described by a rate constant. Numerical calculations reveal that for nearly all possible geometrical arrangements of the three spin system an efficient spin conversion is obtained. Only in the chemically improbable case of a linear group H-X-H no spin conversion is obtained. The efficiency of the spin conversion depends strongly on the lifetime of the H-X-H complex and on the presence of exchange interactions between the two hydrogens. Even moderate exchange couplings cause a quench of the spin conversion. Thus a sufficiently strong binding of the dihydrogen to the S spin is necessary to render the quenching by the exchange interaction ineffective.

Physico-chemical and thermochemical studies of the hydrolytic conversion of amorphous tricalcium phosphate into apatite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Somrani, Saida; Banu, Mihai; Jemal, Mohamed

2005-05-15

The conversion of amorphous tricalcium phosphate with different hydration ratio into apatite in water at 25 deg. C has been studied by microcalorimetry and several physical-chemical methods. The hydrolytic transformation was dominated by two strong exothermic events. A fast, relatively weak, wetting process and a very slow but strong heat release assigned to a slow internal rehydration and the crystallization of the amorphous phase into an apatite. The exothermic phenomenon related to the rehydration exceeded the crystalline transformation enthalpy. Rehydration occurred before the conversion of the amorphous phase into apatite and determined the advancement of the hydrolytic reaction. The apatiticmore » phases formed evolved slightly with time after their formation. The crystallinity increased whereas the amount of HPO{sub 4}{sup 2-} ion decreased. These data allow a better understanding of the behavior of biomaterials involving amorphous phases such as hydroxyapatite plasma-sprayed coatings.« less

History-dependent ion transport through conical nanopipettes and the implications in energy conversion dynamics at nanoscale interfaces.

PubMed

Li, Yan; Wang, Dengchao; Kvetny, Maksim M; Brown, Warren; Liu, Juan; Wang, Gangli

2015-01-01

The dynamics of ion transport at nanostructured substrate-solution interfaces play vital roles in high-density energy conversion, stochastic chemical sensing and biosensing, membrane separation, nanofluidics and fundamental nanoelectrochemistry. Further advancements in these applications require a fundamental understanding of ion transport at nanoscale interfaces. The understanding of the dynamic or transient transport, and the key physical process involved, is limited, which contrasts sharply with widely studied steady-state ion transport features at atomic and nanometer scale interfaces. Here we report striking time-dependent ion transport characteristics at nanoscale interfaces in current-potential ( I - V ) measurements and theoretical analyses. First, a unique non-zero I - V cross-point and pinched I - V curves are established as signatures to characterize the dynamics of ion transport through individual conical nanopipettes. Second, ion transport against a concentration gradient is regulated by applied and surface electrical fields. The concept of ion pumping or separation is demonstrated via the selective ion transport against concentration gradients through individual nanopipettes. Third, this dynamic ion transport process under a predefined salinity gradient is discussed in the context of nanoscale energy conversion in supercapacitor type charging-discharging, as well as chemical and electrical energy conversion. The analysis of the emerging current-potential features establishes the urgently needed physical foundation for energy conversion employing ordered nanostructures. The elucidated mechanism and established methodology can be generalized into broadly-defined nanoporous materials and devices for improved energy, separation and sensing applications.

History-dependent ion transport through conical nanopipettes and the implications in energy conversion dynamics at nanoscale interfaces

DOE PAGES

Li, Yan; Wang, Dengchao; Kvetny, Maksim M.; ...

2014-08-20

The dynamics of ion transport at nanostructured substrate–solution interfaces play vital roles in high-density energy conversion, stochastic chemical sensing and biosensing, membrane separation, nanofluidics and fundamental nanoelectrochemistry. Advancements in these applications require a fundamental understanding of ion transport at nanoscale interfaces. The understanding of the dynamic or transient transport, and the key physical process involved, is limited, which contrasts sharply with widely studied steady-state ion transport features at atomic and nanometer scale interfaces. Here we report striking time-dependent ion transport characteristics at nanoscale interfaces in current–potential (I–V) measurements and theoretical analyses. First, a unique non-zero I–V cross-point and pinched I–Vmore » curves are established as signatures to characterize the dynamics of ion transport through individual conical nanopipettes. Moreoever, ion transport against a concentration gradient is regulated by applied and surface electrical fields. The concept of ion pumping or separation is demonstrated via the selective ion transport against concentration gradients through individual nanopipettes. Third, this dynamic ion transport process under a predefined salinity gradient is discussed in the context of nanoscale energy conversion in supercapacitor type charging–discharging, as well as chemical and electrical energy conversion. Our analysis of the emerging current–potential features establishes the urgently needed physical foundation for energy conversion employing ordered nanostructures. The elucidated mechanism and established methodology can be generalized into broadly-defined nanoporous materials and devices for improved energy, separation and sensing applications.« less

Modularized Production of Value-Added Products and Fuels from Distributed Waste Carbon-Rich Feedstocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weber, Robert S.; Holladay, Johnathan E.

Here, we have adapted and characterized electrolysis reactors to complement the conversion of regional- and community-scale quantities of waste into fuel or chemicals. The overall process must be able to contend with a wide range of feedstocks, must be inherently safe, and should not rely on external facilities for co-reactants or heat rejection and supply. Our current approach is based on the upgrading of bio-oil produced by the hydrothermal liquefaction (HTL) of carbon-containing waste feedstocks. HTL can convert a variety of feedstocks into a bio-oil that requires much less upgrading than the products of other ways of deconstructing biomass. Wemore » are now investigating the use of electrochemical processes for the further conversions needed to transform the bio-oil from HTL into fuel or higher value chemicals. We, and others, have shown that electrochemical reduction can offer adequate reaction rates and at least some of the necessary generality. In addition, an electrochemical reactor necessarily both oxidizes (removes electrons) on one side of the reactor and reduces (adds electrons) on the other side. Therefore, the two types of reactions could, in principle, be coupled to upgrade the bio-oil and simultaneously polish the water that is employed as a reactant and a carrier in the upstream HTL. Here, we overview a notional process, the possible conversion chemistry, and the economics of an HTL-electrochemical process.« less

Modularized Production of Value-Added Products and Fuels from Distributed Waste Carbon-Rich Feedstocks

DOE PAGES

Weber, Robert S.; Holladay, Johnathan E.

2018-05-22

Here, we have adapted and characterized electrolysis reactors to complement the conversion of regional- and community-scale quantities of waste into fuel or chemicals. The overall process must be able to contend with a wide range of feedstocks, must be inherently safe, and should not rely on external facilities for co-reactants or heat rejection and supply. Our current approach is based on the upgrading of bio-oil produced by the hydrothermal liquefaction (HTL) of carbon-containing waste feedstocks. HTL can convert a variety of feedstocks into a bio-oil that requires much less upgrading than the products of other ways of deconstructing biomass. Wemore » are now investigating the use of electrochemical processes for the further conversions needed to transform the bio-oil from HTL into fuel or higher value chemicals. We, and others, have shown that electrochemical reduction can offer adequate reaction rates and at least some of the necessary generality. In addition, an electrochemical reactor necessarily both oxidizes (removes electrons) on one side of the reactor and reduces (adds electrons) on the other side. Therefore, the two types of reactions could, in principle, be coupled to upgrade the bio-oil and simultaneously polish the water that is employed as a reactant and a carrier in the upstream HTL. Here, we overview a notional process, the possible conversion chemistry, and the economics of an HTL-electrochemical process.« less

Improved conversion of herbaceous biomass to biofuels: Potential for modification of key plant characteristics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sladden, S.E.; Bransby, D.I.

1989-10-01

Biomass crops are converted to fuels via biochemical and thermochemical processes. The process preferred depends on properties and cost of available feedstocks, and on the specific products desired. Since most mature biomass crops are composed of up to 80% cell wall fibers, the properties of these fibers determine, to a large degree, the conversion potential of the crop. However, biomass crops also contain small amounts of proteins, soluble carbohydrates and interfering materials (e.g., tannins and silica) which also influence the desirability of the feedstock in specific conversion processes. Fortunately, wide variation exists in the chemical composition of potential biomass crops.more » Although the chemical composition of feedstocks can be influenced significantly with judicious management has species selection, some traits are sufficiently heritable to permit breeding for improved feedstock composition. In addition to breeding for specific compositional traits directly, selection for in vitro digestibility or for easily-measured canopy or physiological traits may lead to more rapid and efficient progress in feedstock improvement, provided those measurements are highly-correlated with desirable feedstock composition. At the same time breeders must improve, or at least avoid damaging, stand longevity, tendency of plants to lodge, and establishment traits (e.g., disease resistance and seedling vigor). 46 refs., 8 tabs.« less

76 FR 9578 - National Center for Environmental Health/Agency for Toxic Substances and Disease Registry (NCEH...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-18

... National Conversation on Public Health and Chemical Exposures Leadership Council Meeting Time and Date: 8... Conversation on Public Health and Chemical Exposures Leadership Council. The National Conversation on Public... public's health from harmful chemical exposures. The Leadership Council provides overall guidance to the...

Applications of de-oiled microalgal biomass towards development of sustainable biorefinery.

PubMed

Maurya, Rahulkumar; Paliwal, Chetan; Ghosh, Tonmoy; Pancha, Imran; Chokshi, Kaumeel; Mitra, Madhusree; Ghosh, Arup; Mishra, Sandhya

2016-08-01

In view of commercialization of microalgal biofuel, the de-oiled microalgal biomass (DMB) is a surplus by-product in the biorefinery process that needs to be exploited to make the process economically attractive and feasible. This DMB, rich in carbohydrates, proteins, and minerals, can be used as feed, fertilizer, and substrate for the production of bioethanol/bio-methane. Further, thermo-chemical conversion of DMB results into fuels and industrially important chemicals. Future prospects of DMB also lie with its conversion into novel biomaterials like nanoparticles and carbon-dot which have biomedical importance. The lowest valued application of DMB is to use it for adsorption of dyes and heavy metals from industrial effluents. This study reviews how DMB can be utilized for different applications and in the generation of valuable co-products. The value addition of DMB would thereby improve the overall cost economics of the microalgal bio-refinery. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cogeneration Technology Alternatives Study (CTAS). Volume 3: Industrial processes

NASA Technical Reports Server (NTRS)

Palmer, W. B.; Gerlaugh, H. E.; Priestley, R. R.

1980-01-01

Cogenerating electric power and process heat in single energy conversion systems rather than separately in utility plants and in process boilers is examined in terms of cost savings. The use of various advanced energy conversion systems are examined and compared with each other and with current technology systems for their savings in fuel energy, costs, and emissions in individual plants and on a national level. About fifty industrial processes from the target energy consuming sectors were used as a basis for matching a similar number of energy conversion systems that are considered as candidate which can be made available by the 1985 to 2000 time period. The sectors considered included food, textiles, lumber, paper, chemicals, petroleum, glass, and primary metals. The energy conversion systems included steam and gas turbines, diesels, thermionics, stirling, closed cycle and steam injected gas turbines, and fuel cells. Fuels considered were coal, both coal and petroleum based residual and distillate liquid fuels, and low Btu gas obtained through the on site gasification of coal. An attempt was made to use consistent assumptions and a consistent set of ground rules specified by NASA for determining performance and cost. Data and narrative descriptions of the industrial processes are given.

On Study of Application of Micro-reactor in Chemistry and Chemical Field

NASA Astrophysics Data System (ADS)

Zhang, Yunshen

2018-02-01

Serving as a micro-scale chemical reaction system, micro-reactor is characterized by high heat transfer efficiency and mass transfer, strictly controlled reaction time and good safety performance; compared with the traditional mixing reactor, it can effectively shorten reaction time by virtue of these advantages and greatly enhance the chemical reaction conversion rate. However, problems still exist in the process where micro-reactor is used for production in chemistry and chemical field, and relevant researchers are required to optimize and perfect the performance of micro-reactor. This paper analyzes specific application of micro-reactor in chemistry and chemical field.

Conversion of bioprocess ethanol to industrial chemical products - Applications of process models for energy-economic assessments

NASA Technical Reports Server (NTRS)

Rohatgi, Naresh K.; Ingham, John D.

1992-01-01

An assessment approach for accurate evaluation of bioprocesses for large-scale production of industrial chemicals is presented. Detailed energy-economic assessments of a potential esterification process were performed, where ethanol vapor in the presence of water from a bioreactor is catalytically converted to ethyl acetate. Results show that such processes are likely to become more competitive as the cost of substrates decreases relative to petrolium costs. A commercial ASPEN process simulation provided a reasonably consistent comparison with energy economics calculated using JPL developed software. Detailed evaluations of the sensitivity of production cost to material costs and annual production rates are discussed.

Preparation of Trivalent Chromium and Rare Earth Composite Conversion Coating on Aluminum Alloy Surface

NASA Astrophysics Data System (ADS)

Huang, Jianzhen

2018-01-01

In this paper, the surface conversion film on 6063 aluminum alloy was prepared by chemical plating process with chromium sulfate, lanthanum sulfate and sodium phosphate as film forming agent. The corrosion resistance and surface morphology of the conversion film were analyzed by pitting corrosion test of copper sulfate and SEM. The results show that when Cr2(SO4)3 is 10 g/L, La2(SO4)3 is 2 g/L, Na3PO4 is 8 g/L, pH value is 3, temperature is 40 °C, reaction time is 10 min, the corrosion resistance of the surface conversion film is the best. The conversion coating is light green, composed of Cr, La, P, Al, O and other elements.

Fates of Chemical Elements in Biomass during Its Pyrolysis.

PubMed

Liu, Wu-Jun; Li, Wen-Wei; Jiang, Hong; Yu, Han-Qing

2017-05-10

Biomass is increasingly perceived as a renewable resource rather than as an organic solid waste today, as it can be converted to various chemicals, biofuels, and solid biochar using modern processes. In the past few years, pyrolysis has attracted growing interest as a promising versatile platform to convert biomass into valuable resources. However, an efficient and selective conversion process is still difficult to be realized due to the complex nature of biomass, which usually makes the products complicated. Furthermore, various contaminants and inorganic elements (e.g., heavy metals, nitrogen, phosphorus, sulfur, and chlorine) embodied in biomass may be transferred into pyrolysis products or released into the environment, arousing environmental pollution concerns. Understanding their behaviors in biomass pyrolysis is essential to optimizing the pyrolysis process for efficient resource recovery and less environmental pollution. However, there is no comprehensive review so far about the fates of chemical elements in biomass during its pyrolysis. Here, we provide a critical review about the fates of main chemical elements (C, H, O, N, P, Cl, S, and metals) in biomass during its pyrolysis. We overview the research advances about the emission, transformation, and distribution of elements in biomass pyrolysis, discuss the present challenges for resource-oriented conversion and pollution abatement, highlight the importance and significance of understanding the fate of elements during pyrolysis, and outlook the future development directions for process control. The review provides useful information for developing sustainable biomass pyrolysis processes with an improved efficiency and selectivity as well as minimized environmental impacts, and encourages more research efforts from the scientific communities of chemistry, the environment, and energy.

Enzymatic conversion of waste cooking oils into alternative fuel--biodiesel.

PubMed

Chen, Guanyi; Ying, Ming; Li, Weizhun

2006-01-01

Production of biodiesel from pure oils through chemical conversion may not be applicable to waste oils/fats. Therefore, enzymatic conversion using immobilized lipase based on Rhizopus orzyae is considered in this article. This article studies this technological process, focusing on optimization of several process parameters, including the molar ratio of methanol to waste oils, biocatalyst load, and adding method, reaction temperature, and water content. The results indicate that methanol/oils ratio of 4, immobilized lipase/oils of 30 wt% and 40 degrees C are suitable for waste oils under 1 atm. The irreversible inactivation of the lipase is presumed and a stepwise addition of methanol to reduce inactivation of immobilized lipases is proposed. Under the optimum conditions the yield of methyl esters is around 88-90%.

Electrocatalysts for carbon dioxide conversion

DOEpatents

Masel, Richard I; Salehi-Khojin, Amin

2015-04-21

Electrocatalysts for carbon dioxide conversion include at least one catalytically active element with a particle size above 0.6 nm. The electrocatalysts can also include a Helper Catalyst. The catalysts can be used to increase the rate, modify the selectivity or lower the overpotential of electrochemical conversion of CO.sub.2. Chemical processes and devices using the catalysts also include processes to produce CO, HCO.sup.-, H.sub.2CO, (HCO.sub.2).sup.-, H.sub.2CO.sub.2, CH.sub.3OH, CH.sub.4, C.sub.2H.sub.4, CH.sub.3CH.sub.2OH, CH.sub.3COO.sup.-, CH.sub.3COOH, C.sub.2H.sub.6, (COOH).sub.2, or (COO.sup.-).sub.2, and a specific device, namely, a CO.sub.2 sensor.

O-Succinyl-L-homoserine-based C4-chemical production: succinic acid, homoserine lactone, γ-butyrolactone, γ-butyrolactone derivatives, and 1,4-butanediol.

PubMed

Hong, Kuk-Ki; Kim, Jeong Hyun; Yoon, Jong Hyun; Park, Hye-Min; Choi, Su Jin; Song, Gyu Hyeon; Lee, Jea Chun; Yang, Young-Lyeol; Shin, Hyun Kwan; Kim, Ju Nam; Cho, Kyung Ho; Lee, Jung Ho

2014-10-01

There has been a significant global interest to produce bulk chemicals from renewable resources using engineered microorganisms. Large research programs have been launched by academia and industry towards this goal. Particularly, C4 chemicals such as succinic acid (SA) and 1,4-butanediol have been leading the path towards the commercialization of biobased technology with the effort of replacing chemical production. Here we present O-Succinyl-L-homoserine (SH) as a new, potentially important platform biochemical and demonstrate its central role as an intermediate in the production of SA, homoserine lactone (HSL), γ-butyrolactone (GBL) and its derivatives, and 1,4-butanediol (BDO). This technology encompasses (1) the genetic manipulation of Escherichia coli to produce SH with high productivity, (2) hydrolysis into SA and homoserine (HS) or homoserine lactone hydrochloride, and (3) chemical conversion of either HS or homoserine lactone HCL (HSL·HCl) into drop-in chemicals in polymer industry. This production strategy with environmental benefits is discussed in the perspective of targeting of fermented product and a process direction compared to petroleum-based chemical conversion, which may reduce the overall manufacturing cost.

Catalytic upgrading of butyric acid towards fine chemicals and biofuels

PubMed Central

Matsakas, Leonidas; Christakopoulos, Paul; Rova, Ulrika

2016-01-01

Fermentation-based production of butyric acid is robust and efficient. Modern catalytic technologies make it possible to convert butyric acid to important fine chemicals and biofuels. Here, current chemocatalytic and biocatalytic conversion methods are reviewed with a focus on upgrading butyric acid to 1-butanol or butyl-butyrate. Supported Ruthenium- and Platinum-based catalyst and lipase exhibit important activities which can pave the way for more sustainable process concepts for the production of green fuels and chemicals. PMID:26994015

Catalytic upgrading of butyric acid towards fine chemicals and biofuels.

PubMed

Sjöblom, Magnus; Matsakas, Leonidas; Christakopoulos, Paul; Rova, Ulrika

2016-04-01

Fermentation-based production of butyric acid is robust and efficient. Modern catalytic technologies make it possible to convert butyric acid to important fine chemicals and biofuels. Here, current chemocatalytic and biocatalytic conversion methods are reviewed with a focus on upgrading butyric acid to 1-butanol or butyl-butyrate. Supported Ruthenium- and Platinum-based catalyst and lipase exhibit important activities which can pave the way for more sustainable process concepts for the production of green fuels and chemicals. © FEMS 2016.

Electro-biocatalytic production of formate from carbon dioxide using an oxygen-stable whole cell biocatalyst.

PubMed

Hwang, Hyojin; Yeon, Young Joo; Lee, Sumi; Choe, Hyunjun; Jang, Min Gee; Cho, Dae Haeng; Park, Sehkyu; Kim, Yong Hwan

2015-06-01

The use of biocatalysts to convert CO2 into useful chemicals is a promising alternative to chemical conversion. In this study, the electro-biocatalytic conversion of CO2 to formate was attempted with a whole cell biocatalyst. Eight species of Methylobacteria were tested for CO2 reduction, and one of them, Methylobacterium extorquens AM1, exhibited an exceptionally higher capability to synthesize formate from CO2 by supplying electrons with electrodes, which produced formate concentrations of up to 60mM. The oxygen stability of the biocatalyst was investigated, and the results indicated that the whole cell catalyst still exhibited CO2 reduction activity even after being exposed to oxygen gas. From the results, we could demonstrate the electro-biocatalytic conversion of CO2 to formate using an obligate aerobe, M. extorquens AM1, as a whole cell biocatalyst without providing extra cofactors or hydrogen gas. This electro-biocatalytic process suggests a promising approach toward feasible way of CO2 conversion to formate. Copyright © 2015 Elsevier Ltd. All rights reserved.

Improved lignocellulose conversion to biofuels with thermophilic bacteria and thermostable enzymes

USDA-ARS?s Scientific Manuscript database

Second generation feedstock, especially nonfood lignocellulosic biomass, has been seen as a potential source for biofuel production. Cost intensive pretreatment operations, including physical, chemical, biological, and slow enzymatic hydrolysis, make the overall process of lignocellulosic conversio...

Energy characterisation of ultrasonic systems for industrial processes.

PubMed

Al-Juboori, Raed A; Yusaf, Talal; Bowtell, Leslie; Aravinthan, Vasantha

2015-03-01

Obtaining accurate power characteristics of ultrasonic treatment systems is an important step towards their industrial scalability. Calorimetric measurements are most commonly used for quantifying the dissipated ultrasonic power. However, accuracy of these measurements is affected by various heat losses, especially when working at high power densities. In this work, electrical power measurements were conducted at all locations in the piezoelectric ultrasonic system equipped with ½″ and ¾″ probes. A set of heat transfer calculations were developed to estimate the convection heat losses from the reaction solution. Chemical dosimeters represented by the oxidation of potassium iodide, Fricke solution and 4-nitrophenol were used to chemically correlate the effect of various electrical amplitudes and treatment regimes. This allowed estimation of sonochemical-efficiency (SE) and energy conversion (XUS) of the ultrasonic system. Results of this study showed overall conversion efficiencies of 60-70%. This correlated well with the chemical dosimeter yield curves of both organic and inorganic aqueous solutions. All dosimeters showed bubble shielding and coalescence effects at higher ultrasonic power levels, less pronounced for the ½″ probe case. SE and XUS values in the range of 10(-10) mol/J and 10(-3) J/J respectively confirmed that conversion of ultrasonic power to chemical yield declined with amplitude. Copyright © 2014 Elsevier B.V. All rights reserved.

Lignin Valorization: Emerging Approaches

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beckham, Gregg T

Lignin, an aromatic biopolymer found in plant cell walls, is a key component of lignocellulosic biomass and generally utilized for heat and power. However, lignin's chemical composition makes it an attractive source for biological and catalytic conversion to fuels and chemicals. Bringing together experts from biology, catalysis, engineering, analytical chemistry, and techno-economic/life-cycle analysis, Lignin Valorization presents a comprehensive, interdisciplinary picture of how lignocellulosic biorefineries could potentially employ lignin valorization technologies. Chapters will specifically focus on the production of fuels and chemicals from lignin and topics covered include (i) methods for isolating lignin in the context of the lignocellulosic biorefinery, (ii)more » thermal, chemo-catalytic, and biological methods for lignin depolymerization, (iii) chemo-catalytic and biological methods for upgrading lignin, (iv) characterization of lignin, and (v) techno-economic and life-cycle analysis of integrated processes to utilize lignin in an integrated biorefinery. The book provides the latest breakthroughs and challenges in upgrading lignin to fuels and chemicals for graduate students and researchers in academia, governmental laboratories, and industry interested in biomass conversion.« less

Conversion of a wet waste feedstock to biocrude by hydrothermal processing in a continuous-flow reactor: grape pomace

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliott, Douglas C.; Schmidt, Andrew J.; Hart, Todd R.

Wet waste feedstocks present an apt opportunity for biomass conversion to fuels by hydrothermal processing. In this study, grape pomace slurries from two varieties, Montepulciano and cabernet sauvignon, have been converted into a biocrude by hydrothermal liquefaction (HTL) in a bench-scale, continuous-flow reactor system. Carbon conversion to gravity-separable biocrude product up to 56 % was accomplished at relatively low temperature (350 C) in a pressurized (sub-critical liquid water) environment (20 MPa) when using grape pomace feedstock slurry with a 16.8 wt% concentration of dry solids processed at a liquid hourly space velocity of 2.1 h-1. Direct oil recovery was achievedmore » without the use of a solvent and biomass trace mineral components were removed by processing steps so that they did not cause processing difficulties. In addition, catalytic hydrothermal gasification (CHG) was effectively applied for HTL byproduct water cleanup using a Ru on C catalyst in a fixed bed producing a gas composed of methane and carbon dioxide from water soluble organics. Conversion of 99.8% of the chemical oxygen demand (COD) left in the aqueous phase was demonstrated. As a result, high conversion of grape pomace to liquid and gas fuel products was found with residual organic contamination in byproduct water reduced to <150 mg/kg COD.« less

Highly-efficient enzymatic conversion of crude algal oils into biodiesel.

PubMed

Wang, Yao; Liu, Jin; Gerken, Henri; Zhang, Chengwu; Hu, Qiang; Li, Yantao

2014-11-01

Energy-intensive chemical conversion of crude algal oils into biodiesel is a major barrier for cost-effective algal biofuel production. To overcome this problem, we developed an enzyme-based platform for conversion of crude algal oils into fatty acid methyl esters. Crude algal oils were extracted from the oleaginous microalga Nannochloropsis oceanica IMET1 and converted by an immobilized lipase from Candida antarctica. The effects of different acyl acceptors, t-butanol as a co-solvent, oil to t-butanol ratio, oil to methanol ratio, temperature and reaction time on biodiesel conversion efficiency were studied. The conversion efficiency reached 99.1% when the conversion conditions were optimized, i.e., an oil to t-butanol weight ratio of 1:1, an oil to methanol molar ratio of 1:12, and a reaction time of 4h at 25°C. The enzymatic conversion process developed in this study may hold a promise for low energy consumption, low wastewater-discharge biochemical conversion of algal feedstocks into biofuels. Published by Elsevier Ltd.

Cogeneration Technology Alternatives Study (CTAS). Volume 6: Computer data. Part 2: Residual-fired nocogeneration process boiler

NASA Technical Reports Server (NTRS)

Knightly, W. F.

1980-01-01

About fifty industrial processes from the largest energy consuming sectors were used as a basis for matching a similar number of energy conversion systems that are considered as candidate which can be made available by the 1985 to 2000 time period. The sectors considered included food, textiles, lumber, paper, chemicals, petroleum, glass, and primary metals. The energy conversion systems included steam and gas turbines, diesels, thermionics, stirling, closed cycle and steam injected gas turbines, and fuel cells. Fuels considered were coal, both coal and petroleum based residual and distillate liquid fuels, and low Btu gas obtained through the on site gasification of coal. Computer generated reports of the fuel consumption and savings, capital costs, economics and emissions of the cogeneration energy conversion systems (ECS's) heat and power matched to the individual industrial processes are presented. National fuel and emissions savings are also reported for each ECS assuming it alone is implemented. Two nocogeneration base cases are included: coal fired and residual fired process boilers.

The role of ion-exchange membrane in energy conversion

NASA Astrophysics Data System (ADS)

Khoiruddin, Aryanti, Putu T. P.; Hakim, Ahmad N.; Wenten, I. Gede

2017-05-01

Ion-exchange membrane (IEM) may play an important role in the future of electrical energy generation which is considered as renewable and clean energy. Fell cell (FC) is one of the promising technologies for solving energy issues in the future owing to the interesting features such as high electrical efficiency, low emissions, low noise level, and modularity. IEM-based processes, such as microbial fuel cell (MFC) and reverse electrodialysis (RED) may be combined with water or wastewater treatment into an integrated system. By using the integrated system, water and energy could be produced simultaneously. The IEM-based processes can be used for direct electricity generation or long term energy storage such as by harnessing surplus electricity from an existing renewable energy system to be converted into hydrogen gas via electrolysis or stored into chemical energy via redox flow battery (RFB). In this paper, recent development and applications of IEM-based processes in energy conversion are reviewed. In addition, perspective and challenges of IEM-based processes in energy conversion are pointed out.

Cogeneration Technology Alternatives Study (CTAS). Volume 6: Computer data. Part 1: Coal-fired nocogeneration process boiler, section A

NASA Technical Reports Server (NTRS)

Knightly, W. F.

1980-01-01

About fifty industrial processes from the largest energy consuming sectors were used as a basis for matching a similar number of energy conversion systems that are considered as candidate which can be made available by the 1985 to 2000 time period. The sectors considered included food, textiles, lumber, paper, chemicals, petroleum, glass, and primary metals. The energy conversion systems included steam and gas turbines, diesels, thermionics, stirling, closed cycle and steam injected gas turbines, and fuel cells. Fuels considered were coal, both coal and petroleum based residual and distillate liquid fuels, and low Btu gas obtained through the on site gasification of coal. Computer generated reports of the fuels consumption and savings, capital costs, economics and emissions of the cogeneration energy conversion systems (ECS's) heat and power matched to the individual industrial processes are presented. National fuel and emissions savings are also reported for each ECS assuming it alone is implemented. Two nocogeneration base cases are included: coal fired and residual fired process boilers.

Cogeneration Technology Alternatives Study (CTAS). Volume 6: Computer data. Part 1: Coal-fired nocogeneration process boiler, section B

NASA Technical Reports Server (NTRS)

Knightly, W. F.

1980-01-01

About fifty industrial processes from the largest energy consuming sectors were used as a basis for matching a similar number of energy conversion systems that are considered as candidate which can be made available by the 1985 to 2000 time period. The sectors considered included food, textiles, lumber, paper, chemicals, petroleum, glass, and primary metals. The energy conversion systems included steam and gas turbines, diesels, thermionics, stirling, closed cycle and steam injected gas turbines, and fuel cells. Fuels considered were coal, both coal and petroleum based residual and distillate liquid fuels, and low Btu gas obtained through the on site gasification of coal. Computer generated reports of the fuel consumption and savings, capital costs, economics and emissions of the cogeneration energy conversion systems (ECS's) heat and power matched to the individual industrial processes are presented. National fuel and emissions savings are also reported for each ECS assuming it alone is implemented. Two nocogeneration base cases are included: coal fired and residual fired process boilers.

Current technologies, economics, and perspectives for 2,5-dimethylfuran production from biomass-derived intermediates.

PubMed

Saha, Basudeb; Abu-Omar, Mahdi M

2015-04-13

Since the U.S. Department of Energy (DOE) published a perspective article that described the potential of the top ten biomass-derived platform chemicals as petroleum replacements for high-value commodity and specialty chemicals, researchers around the world have been motivated to develop technologies for the conversion of biomass and biomass-derived intermediates into chemicals and fuels. Among several biorefinery processes, the conversion of biomass carbohydrates into 2,5-dimethylfuran (DMF) has received significant attention because of its low oxygen content, high energy content, and high octane value. DMF can further serve as a petroleum-replacement, biorenewable feedstock for the production of p-xylene (pX). In this review, we aim specifically to present a concise and up-to-date analysis of DMF production technologies with a critical discussion on catalytic systems, mechanistic insight, and process economics, which includes sensitivity analysis, so that more effective catalysts can be designed. Special emphasis has been given to bifunctional catalysts that improve DMF yields and selectivity and the synergistic effect of the bifunctional sites. Process economics for the current processes and the scope for further improvement are discussed. It is anticipated that the chemistry detailed in this review will guide researchers to develop more practical catalytic processes to enable the economic production of bio-based DMF. Processes for the upgrade of DMF to pX are also described. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

ECUT: Energy Conversion and utilization Technologies program biocatalysis research activity. Generation of chemical intermediates by catalytic oxidative decarboxylation of dilute organic acids

NASA Technical Reports Server (NTRS)

Distefano, S.; Gupta, A.; Ingham, J. D.

1983-01-01

A rhodium-based catalyst was prepared and preliminary experiments were completed where the catalyst appeared to decarboxylate dilute acids at concentrations of 1 to 10 vol%. Electron spin resonance spectroscoy was used to characterize the catalyst as a first step leading toward modeling and optimization of rhodium catalysts. Also, a hybrid chemical/biological process for the production of hydrocarbons has been assessed. These types of catalysts could greatly increase energy efficiency of this process.

Converting lignocellulosic solid waste into ethanol for the State of Washington: an investigation of treatment technologies and environmental impacts.

PubMed

Schmitt, Elliott; Bura, Renata; Gustafson, Rick; Cooper, Joyce; Vajzovic, Azra

2012-01-01

There is little research literature on the conversion of lignocellulosic rich waste streams to ethanol, and even fewer have investigated both the technical aspects and environmental impacts together. This study assessed technical and environmental challenges of converting three lignocellulosic waste streams to ethanol: municipal solid waste (MSW), low grade mixed waste paper (MWP), and organic yard waste (YW). Experimental results showed high conversion yields for all three streams using suitable conversion methods. Environmental impacts are highly dependent on conversion technology, and process conditions used. Life cycle assessment results showed that both chemicals production and waste collection are important factors to be included within a waste-to-ethanol study. Copyright © 2011 Elsevier Ltd. All rights reserved.

Methods of controlling hydrogen fluoride pressure during chemical fabrication processes

DOEpatents

Solovyov, Vyacheslav [Rocky Point, NY; Wiesmann, Harold [Stony Brook, NY

2009-11-24

The present invention is a method for producing a crystalline end-product. The method comprising exposing a fluoride-containing precursor to a hydrogen fluoride absorber under conditions suitable for the conversion of the precursor into the crystalline end-product.

Cogeneration Technology Alternatives Study (CTAS). Volume 6: Computer data. Part 1: Coal-fired nocogeneration process boiler, section A

NASA Technical Reports Server (NTRS)

Knightly, W. F.

1980-01-01

Various advanced energy conversion systems (ECS) are compared with each other and with current technology systems for their savings in fuel energy, costs, and emissions in individual plants and on a national level. About fifty industrial processes from the largest energy consuming sectors were used as a basis for matching a similar number of energy conversion systems that are considered as candidates which can be made available by the 1985 to 2000 time period. The sectors considered included food, textiles, lumber, paper, chemicals, petroleum, glass, and primary metals. The energy conversion systems included steam and gas turbines, diesels, thermionics, stirling, closed cycle and steam injected gas turbines, and fuel cells. Fuels considered were coal, both coal and petroleum based residual and distillate liquid fuels, and low Btu gas obtained through the on-site gasification of coal. Computer generated reports of the fuel consumption and savings, capital costs, economics and emissions of the cogeneration energy conversion systems (ECS's) heat and power matched to the individual industrial processes are presented for coal fired process boilers. National fuel and emissions savings are also reported for each ECS assuming it alone is implemented.

New technology in pulping and bleaching

Treesearch

R. H. Atalla; R. S. Reiner; C. J. Houtman; E. L. Springer

2004-01-01

Innovation in advancing technoogies for production of pulp and paper has been driven, by and large, by the needs to reduce the environmental impact of pulp mills or to enhance the yield in processes of conversion of wood to fibers. "Fiberization" of wood chips is carred out in two categores of processes. One, chemical pulping relies on removing the lignin...

A new dawn for industrial photosynthesis.

PubMed

Robertson, Dan E; Jacobson, Stuart A; Morgan, Frederick; Berry, David; Church, George M; Afeyan, Noubar B

2011-03-01

Several emerging technologies are aiming to meet renewable fuel standards, mitigate greenhouse gas emissions, and provide viable alternatives to fossil fuels. Direct conversion of solar energy into fungible liquid fuel is a particularly attractive option, though conversion of that energy on an industrial scale depends on the efficiency of its capture and conversion. Large-scale programs have been undertaken in the recent past that used solar energy to grow innately oil-producing algae for biomass processing to biodiesel fuel. These efforts were ultimately deemed to be uneconomical because the costs of culturing, harvesting, and processing of algal biomass were not balanced by the process efficiencies for solar photon capture and conversion. This analysis addresses solar capture and conversion efficiencies and introduces a unique systems approach, enabled by advances in strain engineering, photobioreactor design, and a process that contradicts prejudicial opinions about the viability of industrial photosynthesis. We calculate efficiencies for this direct, continuous solar process based on common boundary conditions, empirical measurements and validated assumptions wherein genetically engineered cyanobacteria convert industrially sourced, high-concentration CO(2) into secreted, fungible hydrocarbon products in a continuous process. These innovations are projected to operate at areal productivities far exceeding those based on accumulation and refining of plant or algal biomass or on prior assumptions of photosynthetic productivity. This concept, currently enabled for production of ethanol and alkane diesel fuel molecules, and operating at pilot scale, establishes a new paradigm for high productivity manufacturing of nonfossil-derived fuels and chemicals.

Visualizing chemical functionality in plant cell walls

DOE PAGES

Zeng, Yining; Himmel, Michael E.; Ding, Shi-You

2017-11-30

Understanding plant cell wall cross-linking chemistry and polymeric architecture is key to the efficient utilization of biomass in all prospects from rational genetic modification to downstream chemical and biological conversion to produce fuels and value chemicals. In fact, the bulk properties of cell wall recalcitrance are collectively determined by its chemical features over a wide range of length scales from tissue, cellular to polymeric architectures. Microscopic visualization of cell walls from the nanometer to the micrometer scale offers an in situ approach to study their chemical functionality considering its spatial and chemical complexity, particularly the capabilities of characterizing biomass non-destructivelymore » and in real-time during conversion processes. Microscopic characterization has revealed heterogeneity in the distribution of chemical features, which would otherwise be hidden in bulk analysis. Key microscopic features include cell wall type, wall layering, and wall composition - especially cellulose and lignin distributions. Microscopic tools, such as atomic force microscopy, stimulated Raman scattering microscopy, and fluorescence microscopy, have been applied to investigations of cell wall structure and chemistry from the native wall to wall treated by thermal chemical pretreatment and enzymatic hydrolysis. While advancing our current understanding of plant cell wall recalcitrance and deconstruction, microscopic tools with improved spatial resolution will steadily enhance our fundamental understanding of cell wall function.« less

Visualizing chemical functionality in plant cell walls

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeng, Yining; Himmel, Michael E.; Ding, Shi-You

Understanding plant cell wall cross-linking chemistry and polymeric architecture is key to the efficient utilization of biomass in all prospects from rational genetic modification to downstream chemical and biological conversion to produce fuels and value chemicals. In fact, the bulk properties of cell wall recalcitrance are collectively determined by its chemical features over a wide range of length scales from tissue, cellular to polymeric architectures. Microscopic visualization of cell walls from the nanometer to the micrometer scale offers an in situ approach to study their chemical functionality considering its spatial and chemical complexity, particularly the capabilities of characterizing biomass non-destructivelymore » and in real-time during conversion processes. Microscopic characterization has revealed heterogeneity in the distribution of chemical features, which would otherwise be hidden in bulk analysis. Key microscopic features include cell wall type, wall layering, and wall composition - especially cellulose and lignin distributions. Microscopic tools, such as atomic force microscopy, stimulated Raman scattering microscopy, and fluorescence microscopy, have been applied to investigations of cell wall structure and chemistry from the native wall to wall treated by thermal chemical pretreatment and enzymatic hydrolysis. While advancing our current understanding of plant cell wall recalcitrance and deconstruction, microscopic tools with improved spatial resolution will steadily enhance our fundamental understanding of cell wall function.« less

Visualizing chemical functionality in plant cell walls.

PubMed

Zeng, Yining; Himmel, Michael E; Ding, Shi-You

2017-01-01

Understanding plant cell wall cross-linking chemistry and polymeric architecture is key to the efficient utilization of biomass in all prospects from rational genetic modification to downstream chemical and biological conversion to produce fuels and value chemicals. In fact, the bulk properties of cell wall recalcitrance are collectively determined by its chemical features over a wide range of length scales from tissue, cellular to polymeric architectures. Microscopic visualization of cell walls from the nanometer to the micrometer scale offers an in situ approach to study their chemical functionality considering its spatial and chemical complexity, particularly the capabilities of characterizing biomass non-destructively and in real-time during conversion processes. Microscopic characterization has revealed heterogeneity in the distribution of chemical features, which would otherwise be hidden in bulk analysis. Key microscopic features include cell wall type, wall layering, and wall composition-especially cellulose and lignin distributions. Microscopic tools, such as atomic force microscopy, stimulated Raman scattering microscopy, and fluorescence microscopy, have been applied to investigations of cell wall structure and chemistry from the native wall to wall treated by thermal chemical pretreatment and enzymatic hydrolysis. While advancing our current understanding of plant cell wall recalcitrance and deconstruction, microscopic tools with improved spatial resolution will steadily enhance our fundamental understanding of cell wall function.

Chemistry of sustainability-Part I: Carbon dioxide as an organic synthon and Part II: Study of thermodynamics of cation exchange reactions in semiconductor nanocrystals

NASA Astrophysics Data System (ADS)

Sathe, Ajay A.

Sustainability is an important part of the design and development of new chemical and energy conversion processes. Simply put sustainability is the ability to meet our needs without sacrificing the ability of the next generations to meet theirs. This thesis describes our efforts in developing two orthogonal strategies for the fixation of CO2 by utilizing high energy intermediates which are generated via oxidative or reductive processes on common organic substrates and of thermochemical measurements of cation exchange reactions which will aid the development of new materials relevant for energy conversion and storage. The first chapter lays a background for the challenges and opportunities for the use of CO2 in organic synthesis. The rapidly growing field of continuous flow processing in organic synthesis is introduced, and its importance in the development of sustainable chemical conversions is highlighted. The second chapter describes the development of a novel route to alpha-amino acids via reductive carboxylation of imines. A mechanistic proposal is presented and the reaction is shown to proceed through the intermediacy of alpha-amino alkyl metal species. Possible strategies for designing catalytic and enantioselective variants of the reaction are presented. The third chapter describes the development of a catalytic oxidative carboxylation of olefins to yield cyclic carbonates. The importance of flow chemistry and membrane separation is demonstrated by allowing the combination of mutually incompatible reagents in a single reaction sequence. While the use of carbon dioxide for synthesis of organic fine chemicals is not expected to help reduce the atmospheric carbon dioxide levels, or tackle climate change, it certainly has the potential to reduce our dependence on non-sustainable carbon feedstocks, and help achieve a carbon neutral chemical life cycle. Having described the use of carbon dioxide and flow chemistry for sustainable chemical conversion, the fourth chapter introduces the role of nanomaterials in sustainable solar energy conversion and storage. The use of cation exchange reactions in nanocrystals to access novel materials is highlighted. Despite having shown tremendous promise in the synthetic applications, the fundamental measurements of the thermodynamic and kinetic parameters of a cation exchange reaction are largely non-existent. This impedes the future growth of this powerful methodology. The technique of isothermal titration calorimetry is introduced, and its importance to studying the thermochemical changes occurring during cation exchange is outlined. The final chapter presents results obtained from the isothermal titration calorimetry on the prototypical cation exchange reaction between cadmium selenide and silver ions. The role of nanoparticle size, identity of the silver salt, solvent, surface ligands and temperature is studied. Recommendations for future investigations using ITC as well as other characterization techniques for discerning the kinetics of cation exchange are presented. I believe that a more unified mechanistic understanding of the cation exchange process in nanomaterials will aid the development of more efficient and robust materials for applications in a wide variety of fields.

A new approach of probe sonication assisted ionic liquid conversion of glucose, cellulose and biomass into 5-hydroxymethylfurfural.

PubMed

Sarwono, Ariyanti; Man, Zakaria; Muhammad, Nawshad; Khan, Amir Sada; Hamzah, Wan Suzaini Wan; Rahim, Asyraf Hanim Abdul; Ullah, Zahoor; Wilfred, Cecilia Devi

2017-07-01

5-Hydroxymethylfurfural (HMF) has been identified as a promising biomass-derived platform chemical. In this study, one pot production of HMF was studied in ionic liquid (IL) under probe sonication technique. Compared with the conventional heating technique, the use of probe ultrasonic irradiation reduced the reaction time from hours to minutes. Glucose, cellulose and local bamboo, treated with ultrasonic, produced HMF in the yields of 43%, 31% and 13% respectively, within less than 10min. The influence of various parameters such as acoustic power, reaction time, catalysts and glucose loading were studied. About 40% HMF yield at glucose conversion above 90% could be obtained with 2% of catalyst in 3min. Negligible amount of soluble by-product was detected, and humin formation could be controlled by adjusting the different process parameters. Upon extraction of HMF, the mixture of ionic liquid and catalyst could be reused and exhibited no significant reduction of HMF yield over five successive runs. The purity of regenerated [C 4 C 1 im]Cl and HMF was confirmed by NMR spectroscopy, indicating neither changes in the chemical structure nor presence of any major contaminants during the conversion under ultrasonic treatment. 13 C NMR suggests that [C 4 C 1 im]Cl/CrCl 3 catalyses mutarotation of α-glucopyranose to β-glucopyranose leading to isomerization and finally conversion to HMF. The experimental results demonstrate that the use of probe sonication technique for conversion to HMF provides a positive process benefit. Copyright © 2017 Elsevier B.V. All rights reserved.

History-dependent ion transport through conical nanopipettes and the implications in energy conversion dynamics at nanoscale interfaces† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c4sc02195a Click here for additional data file.

PubMed Central

Li, Yan; Wang, Dengchao; Kvetny, Maksim M.; Brown, Warren; Liu, Juan

2015-01-01

The dynamics of ion transport at nanostructured substrate–solution interfaces play vital roles in high-density energy conversion, stochastic chemical sensing and biosensing, membrane separation, nanofluidics and fundamental nanoelectrochemistry. Further advancements in these applications require a fundamental understanding of ion transport at nanoscale interfaces. The understanding of the dynamic or transient transport, and the key physical process involved, is limited, which contrasts sharply with widely studied steady-state ion transport features at atomic and nanometer scale interfaces. Here we report striking time-dependent ion transport characteristics at nanoscale interfaces in current–potential (I–V) measurements and theoretical analyses. First, a unique non-zero I–V cross-point and pinched I–V curves are established as signatures to characterize the dynamics of ion transport through individual conical nanopipettes. Second, ion transport against a concentration gradient is regulated by applied and surface electrical fields. The concept of ion pumping or separation is demonstrated via the selective ion transport against concentration gradients through individual nanopipettes. Third, this dynamic ion transport process under a predefined salinity gradient is discussed in the context of nanoscale energy conversion in supercapacitor type charging–discharging, as well as chemical and electrical energy conversion. The analysis of the emerging current–potential features establishes the urgently needed physical foundation for energy conversion employing ordered nanostructures. The elucidated mechanism and established methodology can be generalized into broadly-defined nanoporous materials and devices for improved energy, separation and sensing applications. PMID:28706626

Dry Reforming of Methane in a Gliding Arc Plasmatron: Towards a Better Understanding of the Plasma Chemistry.

PubMed

Cleiren, Emelie; Heijkers, Stijn; Ramakers, Marleen; Bogaerts, Annemie

2017-10-23

Dry reforming of methane (DRM) in a gliding arc plasmatron is studied for different CH 4 fractions in the mixture. The CO 2 and CH 4 conversions reach their highest values of approximately 18 and 10 %, respectively, at 25 % CH 4 in the gas mixture, corresponding to an overall energy cost of 10 kJ L -1 (or 2.5 eV per molecule) and an energy efficiency of 66 %. CO and H 2 are the major products, with the formation of smaller fractions of C 2 H x (x=2, 4, or 6) compounds and H 2 O. A chemical kinetics model is used to investigate the underlying chemical processes. The calculated CO 2 and CH 4 conversion and the energy efficiency are in good agreement with the experimental data. The model calculations reveal that the reaction of CO 2 (mainly at vibrationally excited levels) with H radicals is mainly responsible for the CO 2 conversion, especially at higher CH 4 fractions in the mixture, which explains why the CO 2 conversion increases with increasing CH 4 fraction. The main process responsible for CH 4 conversion is the reaction with OH radicals. The excellent energy efficiency can be explained by the non-equilibrium character of the plasma, in which the electrons mainly activate the gas molecules, and by the important role of the vibrational kinetics of CO 2 . The results demonstrate that a gliding arc plasmatron is very promising for DRM. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Conversion of Nuclear Waste to Molten Glass: Cold-Cap Reactions in Crucible Tests

DOE PAGES

Xu, Kai; Hrma, Pavel; Rice, Jarrett A.; ...

2016-05-23

The feed-to-glass conversion, which comprises complex chemical reactions and phase transitions, occurs in the cold cap during nuclear waste vitrification. Here, to investigate the conversion process, we analyzed heat-treated samples of a simulated high-level waste feed using X-ray diffraction, electron probe microanalysis, leaching tests, and residual anion analysis. Feed dehydration, gas evolution, and borate phase formation occurred at temperatures below 700°C before the emerging glass-forming melt was completely connected. Above 700°C, intermediate aluminosilicate phases and quartz particles gradually dissolved in the continuous borosilicate melt, which expanded with transient foam. Finally, knowledge of the chemistry and physics of feed-to-glass conversion willmore » help us control the conversion path by changing the melter feed makeup to maximize the glass production rate.« less

Refining of plant oils to chemicals by olefin metathesis.

PubMed

Chikkali, Samir; Mecking, Stefan

2012-06-11

Plant oils are attractive substrates for the chemical industry. Their scope for the production of chemicals can be expanded by sophisticated catalytic conversions. Olefin metathesis is an example, which also illustrates generic issues of "biorefining" to chemicals. Utilization on a large scale requires high catalyst activities, which influences the choice of the metathesis reaction. The mixture of different fatty acids composing a technical-grade plant oil substrate gives rise to a range of products. This decisively determines possible process schemes, and potentially provides novel chemicals and intermediates not employed to date. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ortho-para-H2 conversion by hydrogen exchange: comparison of theory and experiment.

PubMed

Lique, François; Honvault, Pascal; Faure, Alexandre

2012-10-21

We report fully-quantum time-independent calculations of cross sections and rate coefficients for the collisional (de)excitation of H(2) by H. Our calculations are based on the H(3) global potential energy surface of Mielke et al. [J. Chem. Phys. 116, 4142 (2002)]. The reactive hydrogen exchange channels are taken into account. We show that the ortho-para and para-ortho conversion of H(2) are significant processes at temperatures above ~300 K and for the last process we provide the first comparison with available experimental rate coefficients between 300 and 444 K. The good agreement between theory and experiment is a new illustration of our detailed understanding of the simplest chemical reaction. The importance of the ortho-para-H(2) conversion by hydrogen exchange in astrophysics is discussed.

Comparing solar energy alternatives

NASA Astrophysics Data System (ADS)

White, J. R.

1984-03-01

This paper outlines a computational procedure for comparing the merits of alternative processes to convert solar radiation to heat, electrical power, or chemical energy. The procedure uses the ratio of equipment investment to useful work as an index. Comparisons with conversion counterparts based on conventional fuels are also facilitated by examining this index. The procedure is illustrated by comparisons of (1) photovoltaic converters of differing efficiencies; (2) photovoltaic converters with and without focusing concentrators; (3) photovoltaic conversion plus electrolysis vs photocatalysis for the production of hydrogen; (4) photovoltaic conversion plus plasma arcs vs photocatalysis for nitrogen fixation. Estimates for conventionally-fuelled processes are included for comparison. The reasons why solar-based concepts fare poorly in such comparisons are traced to the low energy density of solar radiation and its low stream time factor resulting from the limited number of daylight hours available and clouds obscuring the sun.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eun, H.C.; Cho, Y.Z.; Choi, J.H.

A regeneration process of LiCl-KCl eutectic waste salt generated from the pyrochemical process of spent nuclear fuel has been studied. This regeneration process is composed of a chemical conversion process and a vacuum distillation process. Through the regeneration process, a high efficiency of renewable salt recovery can be obtained from the waste salt and rare earth nuclides in the waste salt can be separated as oxide or phosphate forms. Thus, the regeneration process can contribute greatly to a reduction of the waste volume and a creation of durable final waste forms. (authors)

Magnetic resonance imaging of chemistry.

PubMed

Britton, Melanie M

2010-11-01

Magnetic resonance imaging (MRI) has long been recognized as one of the most important tools in medical diagnosis and research. However, MRI is also well placed to image chemical reactions and processes, determine the concentration of chemical species, and look at how chemistry couples with environmental factors, such as flow and heterogeneous media. This tutorial review will explain how magnetic resonance imaging works, reviewing its application in chemistry and its ability to directly visualise chemical processes. It will give information on what resolution and contrast are possible, and what chemical and physical parameters can be measured. It will provide examples of the use of MRI to study chemical systems, its application in chemical engineering and the identification of contrast agents for non-clinical applications. A number of studies are presented including investigation of chemical conversion and selectivity in fixed-bed reactors, temperature probes for catalyst pellets, ion mobility during tablet dissolution, solvent dynamics and ion transport in Nafion polymers and the formation of chemical waves and patterns.

Development of Lignocellulosic Biorefinery Technologies: Recent Advances and Current Challenges

DOE PAGES

Amore, Antonella; Ciesielski, Peter N.; Lin, Chien-Yuan; ...

2016-06-06

We describe some recent developments of the biorefinery concept within this review, which focuses on the efforts required to make the lignocellulosic biorefinery a sustainable and economically viable reality. In spite of the major research and development endeavours directed towards this goal over the past several decades, the integrated production of biofuel and other bio-based products still needs to be optimized from both technical and economical perspectives. This review will highlight recent progress towards the optimization of the major biorefinery processes, including biomass pretreatment and fractionation, saccharification of sugars, and conversion of sugars and lignin into fuels and chemical precursors.more » Additionally, advances in genetic modification of biomass structure and composition for the purpose of enhancing the efficacy of conversion processes, which is emerging as a powerful tool for tailoring biomass fated for the biorefinery, will be overviewed. The continual improvement of these processes and their integration in the format of a modern biorefinery is paving the way for a sustainable bio-economy which will displace large portions of petroleum-derived fuels and chemicals with renewable substitutes.« less

Development of Lignocellulosic Biorefinery Technologies: Recent Advances and Current Challenges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amore, Antonella; Ciesielski, Peter N.; Lin, Chien-Yuan

We describe some recent developments of the biorefinery concept within this review, which focuses on the efforts required to make the lignocellulosic biorefinery a sustainable and economically viable reality. In spite of the major research and development endeavours directed towards this goal over the past several decades, the integrated production of biofuel and other bio-based products still needs to be optimized from both technical and economical perspectives. This review will highlight recent progress towards the optimization of the major biorefinery processes, including biomass pretreatment and fractionation, saccharification of sugars, and conversion of sugars and lignin into fuels and chemical precursors.more » Additionally, advances in genetic modification of biomass structure and composition for the purpose of enhancing the efficacy of conversion processes, which is emerging as a powerful tool for tailoring biomass fated for the biorefinery, will be overviewed. The continual improvement of these processes and their integration in the format of a modern biorefinery is paving the way for a sustainable bio-economy which will displace large portions of petroleum-derived fuels and chemicals with renewable substitutes.« less

Catalytic conversion of methane to methanol using Cu-zeolites.

PubMed

Alayon, Evalyn Mae C; Nachtegaal, Maarten; Ranocchiari, Marco; van Bokhoven, Jeroen A

2012-01-01

The conversion of methane to value-added liquid chemicals is a promising answer to the imminent demand for fuels and chemical synthesis materials in the advent of a dwindling petroleum supply. Current technology requires high energy input for the synthesis gas production, and is characterized by low overall selectivity, which calls for alternative reaction routes. The limitation to achieve high selectivity is the high C-H bond strength of methane. High-temperature reaction systems favor gas-phase radical reactions and total oxidation. This suggests that the catalysts for methane activation should be active at low temperatures. The enzymatic-inspired metal-exchanged zeolite systems apparently fulfill this need, however, methanol yield is low and a catalytic process cannot yet be established. Homogeneous and heterogeneous catalytic systems have been described which stabilize the intermediate formed after the first C-H activation. The understanding of the reaction mechanism and the determination of the active metal sites are important for formulating strategies for the upgrade of methane conversion catalytic technologies.

Plasmonic hot carrier dynamics in solid-state and chemical systems for energy conversion

DOE PAGES

Narang, Prineha; Sundararaman, Ravishankar; Atwater, Harry A.

2016-06-11

Surface plasmons provide a pathway to efficiently absorb and confine light in metallic nanostructures, thereby bridging photonics to the nano scale. The decay of surface plasmons generates energetic ‘hot’ carriers, which can drive chemical reactions or be injected into semiconductors for nano-scale photochemical or photovoltaic energy conversion. Novel plasmonic hot carrier devices and architectures continue to be demonstrated, but the complexity of the underlying processes make a complete microscopic understanding of all the mechanisms and design considerations for such devices extremely challenging.Here,we review the theoretical and computational efforts to understand and model plasmonic hot carrier devices.We split the problem intomore » three steps: hot carrier generation, transport and collection, and review theoretical approaches with the appropriate level of detail for each step along with their predictions. As a result, we identify the key advances necessary to complete the microscopic mechanistic picture and facilitate the design of the next generation of devices and materials for plasmonic energy conversion.« less

H2 Ortho-to-para Conversion on Grains: A Route to Fast Deuterium Fractionation in Dense Cloud Cores?

NASA Astrophysics Data System (ADS)

Bovino, S.; Grassi, T.; Schleicher, D. R. G.; Caselli, P.

2017-11-01

Deuterium fractionation, I.e., the enhancement of deuterated species with respect to non-deuterated ones, is considered to be a reliable chemical clock of star-forming regions. This process is strongly affected by the ortho-to-para H2 ratio. In this Letter we explore the effect of the ortho-para (o-p) H2 conversion on grains on the deuteration timescale in fully-depleted dense cores, including the most relevant uncertainties that affect this complex process. We show that (I) the o-p H2 conversion on grains is not strongly influenced by the uncertainties on the conversion time and the sticking coefficient, and (II) that the process is controlled by the temperature and the residence time of ortho-H2 on the surface, I.e., by the binding energy. We find that for binding energies between 330 and 550 K, depending on the temperature, the o-p H2 conversion on grains can shorten the deuterium fractionation timescale by orders of magnitude, opening a new route for explaining the large observed deuteration fraction D frac in dense molecular cloud cores. Our results suggest that the star formation timescale, when estimated through the timescale to reach the observed deuteration fractions, might be shorter than previously proposed. However, more accurate measurements of the binding energy are needed in order to better assess the overall role of this process.

Synergistic Carbon Dioxide Capture and Conversion in Porous Materials.

PubMed

Zhang, Yugen; Lim, Diane S W

2015-08-24

Global climate change and excessive CO2 emissions have caused widespread public concern in recent years. Tremendous efforts have been made towards CO2 capture and conversion. This has led to the development of numerous porous materials as CO2 capture sorbents. Concurrently, the conversion of CO2 into value-added products by chemical methods has also been well-documented recently. However, realizing the attractive prospect of direct, in situ chemical conversion of captured CO2 into other chemicals remains a challenge. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Removal of polycyclic aromatic hydrocarbons in aqueous environment by chemical treatments: a review.

PubMed

Rubio-Clemente, Ainhoa; Torres-Palma, Ricardo A; Peñuela, Gustavo A

2014-04-15

Due to their carcinogenic, mutagenic and teratogenic potential, the removal of polycyclic aromatic hydrocarbons (PAHs) from aqueous environment using physical, biological and chemical processes has been studied by several researchers. This paper reviews the current state of knowledge concerning PAHs including their physico-chemical properties, input sources, occurrence, adverse effects and conventional and alternative chemical processes applied for their removal from water. The mechanisms and reactions involved in each treatment method are reported, and the effects of various variables on the PAH degradation rate as well as the extent of degradation are also discussed. Extensive literature analysis has shown that an effective way to perform the conversion and mineralization of this type of substances is the application of advanced oxidation processes (AOPs). Furthermore, combined processes, particularly AOPs coupled with biological treatments, seem to be one of the best solutions for the treatment of effluents containing PAHs. Copyright © 2013 Elsevier B.V. All rights reserved.

Transition metal mediated transformations of small molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sen, Ayusman

Catalysis at metal centers is of great scientific, as well as practical, importance because of the high efficiency, high specificity, and low energy demands often associated with such systems. The two major themes of our research are (a) the design of metal-based systems for the synthesis of novel classes of polymers and (b) the identification of new metal-catalyzed systems for the conversion of biomass to fuels and chemicals, and related “green” chemical processes.

Alternative Fuels Data Center: Ethanol Vehicle Emissions

Science.gov Websites

Availability Conversions Emissions Laws & Incentives Ethanol Vehicle Emissions When blended with gasoline emissions of regulated pollutants, toxic chemicals, and greenhouse gases (GHGs). The use of high-level extraction, processing, manufacturing, distribution, use, and disposal or recycling. When comparing fuels, a

Nicholas J. Nagle | NREL

Science.gov Websites

presentation. Featured Publications "Impact of biomass processing, blending and densification, on J. Nagle Photo of Nicholas J. Nagle Nicholas Nagle Researcher IV-Chemical Engineering Nick.Nagle impact on lignin upgrading post conversion. As feedstocks rapidly evolve into new formats, such as

Environmental applications of HTC technology: Biochar production, carbon sequestration, and waste conversion

USDA-ARS?s Scientific Manuscript database

Motivations for the development and use of hydrothermal carbonization (or wet pyrolysis) have been primarily directed towards the sustainable creation of carbon nanomaterials/nanostructures for use in applications ranging from hydrogen storage to chemical adsorption. The utility of this process, how...

ECUT: Energy Conversion and Utilization Technologies program. Chemical Processes project report, FY 1982

NASA Technical Reports Server (NTRS)

Wilcox, R. E. (Compiler)

1983-01-01

Planned research efforts and reorganization of the Project as the Biocatalysis Research Activity are described, including the following topics: electrocatalysts, fluid extraction, ammonia synthesis, biocatalysis, membrane fouling, energy and economic analysis, decarboxylation, microscopic reaction models, plasmid monitoring, and reaction kinetics.

Hybrid bioinorganic approach to solar-to-chemical conversion.

PubMed

Nichols, Eva M; Gallagher, Joseph J; Liu, Chong; Su, Yude; Resasco, Joaquin; Yu, Yi; Sun, Yujie; Yang, Peidong; Chang, Michelle C Y; Chang, Christopher J

2015-09-15

Natural photosynthesis harnesses solar energy to convert CO2 and water to value-added chemical products for sustaining life. We present a hybrid bioinorganic approach to solar-to-chemical conversion in which sustainable electrical and/or solar input drives production of hydrogen from water splitting using biocompatible inorganic catalysts. The hydrogen is then used by living cells as a source of reducing equivalents for conversion of CO2 to the value-added chemical product methane. Using platinum or an earth-abundant substitute, α-NiS, as biocompatible hydrogen evolution reaction (HER) electrocatalysts and Methanosarcina barkeri as a biocatalyst for CO2 fixation, we demonstrate robust and efficient electrochemical CO2 to CH4 conversion at up to 86% overall Faradaic efficiency for ≥ 7 d. Introduction of indium phosphide photocathodes and titanium dioxide photoanodes affords a fully solar-driven system for methane generation from water and CO2, establishing that compatible inorganic and biological components can synergistically couple light-harvesting and catalytic functions for solar-to-chemical conversion.

Hybrid bioinorganic approach to solar-to-chemical conversion

PubMed Central

Nichols, Eva M.; Gallagher, Joseph J.; Liu, Chong; Su, Yude; Resasco, Joaquin; Yu, Yi; Sun, Yujie; Yang, Peidong; Chang, Michelle C. Y.; Chang, Christopher J.

2015-01-01

Natural photosynthesis harnesses solar energy to convert CO2 and water to value-added chemical products for sustaining life. We present a hybrid bioinorganic approach to solar-to-chemical conversion in which sustainable electrical and/or solar input drives production of hydrogen from water splitting using biocompatible inorganic catalysts. The hydrogen is then used by living cells as a source of reducing equivalents for conversion of CO2 to the value-added chemical product methane. Using platinum or an earth-abundant substitute, α-NiS, as biocompatible hydrogen evolution reaction (HER) electrocatalysts and Methanosarcina barkeri as a biocatalyst for CO2 fixation, we demonstrate robust and efficient electrochemical CO2 to CH4 conversion at up to 86% overall Faradaic efficiency for ≥7 d. Introduction of indium phosphide photocathodes and titanium dioxide photoanodes affords a fully solar-driven system for methane generation from water and CO2, establishing that compatible inorganic and biological components can synergistically couple light-harvesting and catalytic functions for solar-to-chemical conversion. PMID:26305947

Phase Restructuring in Transition Metal Dichalcogenides for Highly Stable Energy Storage.

PubMed

Leng, Kai; Chen, Zhongxin; Zhao, Xiaoxu; Tang, Wei; Tian, Bingbing; Nai, Chang Tai; Zhou, Wu; Loh, Kian Ping

2016-09-28

Achieving homogeneous phase transition and uniform charge distribution is essential for good cycle stability and high capacity when phase conversion materials are used as electrodes. Herein, we show that chemical lithiation of bulk 2H-MoS 2 distorts its crystalline domains in three primary directions to produce mosaic-like 1T' nanocrystalline domains, which improve phase and charge uniformity during subsequent electrochemical phase conversion. 1T'-Li x MoS 2 , a macroscopic dense material with interconnected nanoscale grains, shows excellent cycle stability and rate capability in a lithium rechargeable battery compared to bulk or exfoliated-restacked MoS 2 . Transmission electron microscopy studies reveal that the interconnected MoS 2 nanocrystals created during the phase change process are reformable even after multiple cycles of galvanostatic charging/discharging, which allows them to play important roles in the long term cycling performance of the chemically intercalated TMD materials. These studies shed light on how bulk TMDs can be processed into quasi-2D nanophase material for stable energy storage.

Reactivity study on thermal cracking of vacuum residues

NASA Astrophysics Data System (ADS)

León, A. Y.; Díaz, S. D.; Rodríguez, R. C.; Laverde, D.

2016-02-01

This study focused on the process reactivity of thermal cracking of vacuum residues from crude oils mixtures. The thermal cracking experiments were carried out under a nitrogen atmosphere at 120psi between 430 to 500°C for 20 minutes. Temperature conditions were established considering the maximum fractional conversion reported in tests of thermogravimetry performed in the temperature range of 25 to 600°C, with a constant heating rate of 5°C/min and a nitrogen flow rate of 50ml/min. The obtained products were separated in to gases, distillates and coke. The results indicate that the behaviour of thermal reactivity over the chemical composition is most prominent for the vacuum residues with higher content of asphaltenes, aromatics, and resins. Finally some correlations were obtained in order to predict the weight percentage of products from its physical and chemical properties such as CCR, SARA (saturates, aromatics, resins, asphaltenes) and density. The results provide new knowledge of the effect of temperature and the properties of vacuum residues in thermal conversion processes.

Semiconductor photoelectrochemistry

NASA Technical Reports Server (NTRS)

Buoncristiani, A. M.; Byvik, C. E.

1983-01-01

Semiconductor photoelectrochemical reactions are investigated. A model of the charge transport processes in the semiconductor, based on semiconductor device theory, is presented. It incorporates the nonlinear processes characterizing the diffusion and reaction of charge carriers in the semiconductor. The model is used to study conditions limiting useful energy conversion, specifically the saturation of current flow due to high light intensity. Numerical results describing charge distributions in the semiconductor and its effects on the electrolyte are obtained. Experimental results include: an estimate rate at which a semiconductor photoelectrode is capable of converting electromagnetic energy into chemical energy; the effect of cell temperature on the efficiency; a method for determining the point of zero zeta potential for macroscopic semiconductor samples; a technique using platinized titanium dioxide powders and ultraviolet radiation to produce chlorine, bromine, and iodine from solutions containing their respective ions; the photoelectrochemical properties of a class of layered compounds called transition metal thiophosphates; and a technique used to produce high conversion efficiency from laser radiation to chemical energy.

Coordination nano-space as stage of hydrogen ortho-para conversion.

PubMed

Kosone, Takashi; Hori, Akihiro; Nishibori, Eiji; Kubota, Yoshiki; Mishima, Akio; Ohba, Masaaki; Tanaka, Hiroshi; Kato, Kenichi; Kim, Jungeun; Real, José Antonio; Kitagawa, Susumu; Takata, Masaki

2015-07-01

The ability to design and control properties of nano-sized space in porous coordination polymers (PCPs) would provide us with an ideal stage for fascinating physical and chemical phenomena. We found an interconversion of nuclear-spin isomers for hydrogen molecule H2 adsorbed in a Hofmann-type PCP, {Fe(pz)[Pd(CN)4]} (pz=pyrazine), by the temperature dependence of Raman spectra. The ortho (o)-para (p) conversion process of H2 is forbidden for an isolated molecule. The charge density study using synchrotron radiation X-ray diffraction reveals the electric field generated in coordination nano-space. The present results corroborate similar findings observed on different systems and confirm that o-p conversion can occur on non-magnetic solids and that electric field can induce the catalytic hydrogen o-p conversion.

Advanced coal conversion process demonstration. Technical progress report for the period July 1, 1995--September 30, 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1997-05-01

This report describes the technical progress made on the Advanced Coal Conversion Process (ACCP) Demonstration Project from July 1, 1995 through September 30, 1995. The ACCP Demonstration Project is a US Department of Energy (DOE) Clean Coal Technology Project. This project demonstrates an advanced, thermal, coal upgrading process, coupled with physical cleaning techniques, that is designed to upgrade high-moisture, low-rank coals to a high-quality, low-sulfur fuel, registered as the SynCoal process. The coal is processed through three stages (two heating stages followed by an inert cooling stage) of vibrating fluidized bed reactors that remove chemically bound water, carboxyl groups, andmore » volatile sulfur compounds. After thermal upgrading, the cola is put through a deep-bed stratifier cleaning process to separate the pyrite-rich ash from the coal.« less

Irradiation enhancement of biomass conversion

NASA Astrophysics Data System (ADS)

Smith, G. S.; Kiesling, H. E.; Galyean, M. L.; Bader, J. R.

The vast supply of cellulosic agricultural residues and industrial by-products that is produced each year is a prospective resource of biomass suitable for conversion to useful products such as feedstock for the chemicals industry and feedstuffs for the livestock industry. Conversions of such biomass is poor at present, and utilization is inefficient, because of physio-chemical barriers to biological degradation and (or) anti-quality components such as toxicants that restrict biological usages. Improvements in biodegradability of ligno-cellulosic materials have been accomplished by gamma-ray and electron-beam irradiation at intermediate dosage (˜ 50 Mrad; .5 MGy); but applications of the technology have been hampered by questionable interpretations of results. Recent research with organic wastes such as sewage sludge and straw suggests opportunity for important applications of irradiation technology in enhancement of biomass conversion. Data from experiments using irradiated straw as feed for ruminants are presented and discussed in relation to research on prospective usage of sewage products as feed for ruminants. Findings are discussed in regard to prospective applications in industrial fermentation processes. Possible usage of irradiation technology for destruction of toxicants in exotic plants is considered in regard to prospective new feedstuffs.

(Bio)Chemical Tailoring of Biogenic 3-D Nanopatterned Templates with Energy-Relevant Functionalities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sandhage, Kenneth H; Kroger, Nils

2014-09-08

The overall aim of this research has been to obtain fundamental understanding of (bio)chemical methodologies that will enable utilization of the unique 3-D nanopatterned architectures naturally produced by diatoms for the syntheses of advanced functional materials attractive for applications in energy harvesting/conversion and storage. This research has been conducted in three thrusts: Thrust 1 (In vivo immobilization of proteins in diatom biosilica) is directed towards elucidating the fundamental mechanism(s) underlying the cellular processes of in vivo immobilization of proteins in diatom silica. Thrust 2 (Shape-preserving reactive conversion of diatom biosilica into porous, high-surface area inorganic replicas) is aimed at understandingmore » the fundamental mechanisms of shape preservation and nanostructural evolution associated with the reactive conversion and/or coating-based conversion of diatom biosilica templates into porous inorganic replicas. Thrust 3 (Immobilization of energy-relevant enzymes in diatom biosilica and onto diatom biosilica-derived inorganic replicas) involves use of the results from both Thrust 1 and 2 to develop strategies for in vivo and in vitro immobilization of enzymes in/on diatom biosilica and diatom biosilica-derived inorganic replicas, respectively. This Final Report describes progress achieved in all 3 of these thrusts.« less

Flux observations of isoprene oxidation products above a South East US forest point to chemical conversions on leaf canopy surface

NASA Astrophysics Data System (ADS)

Misztal, P. K.; Su, L.; Park, J.; Holzinger, R.; Nguyen, T.; Teng, A.; St Clair, J. M.; Wennberg, P. O.; Crounse, J.; Seco, R.; Karl, T.; Kaser, L.; Hansel, A.; Canaval, E.; Keutsch, F. N.; Mak, J. E.; Guenther, A. B.; Goldstein, A. H.; Mentler, B.; Lepesant, B.; Schnitzler, J. P.; Partoll, E.

2016-12-01

Isoprene is globally the dominant biogenic VOC (BVOC) emitted by the biosphere. Isoprene rapidly reacts with hydroxyl radicals in the atmosphere, forming oxidized carbonaceous gases some of which further react to form secondary organic aerosol. Isoprene oxidation proceeds simultaneously via NO and HO2 oxidation pathways with relative proportions depending mainly on the amount of available NOx (NO +NO2). Recent SOA modeling of HO2 oxidation of isoprene peroxides and epoxides reveal different SOA yields but few field studies are available to investigate these processes. Understanding of the fundamental chemical and physical processes controlling the fate of isoprene oxidation products is needed to improve SOA modeling under highly variable NOx concentrations and with the branching ratio between HO2 and NO pathways changing as a function of time of day. Plants are an important sink for many atmospheric chemicals formed in the atmosphere but the role of canopy surfaces is not typically accounted for when modeling atmospheric chemistry. Based on simultaneous flux measurements of isoprene carbonyls (MVK+MAC) by proton transfer reaction mass spectrometry and isoprene hydroxy hydroperoxides and epoxy diols (ISOPOOH+IEPOX) by tandem chemical ionization mass spectrometry, we show that the relative proportions of concentrations of these first-order isoprene products exhibit different diurnal patterns, dependent on NOx. Furthermore, a different diurnal flux pattern observed for first order products of NO and HO2 reactions reveals the occurrence of peroxide conversions to carbonyls at the canopy surface resulting in observed positive net emission flux of MVK+MAC in the afternoon. We hypothesize that the plant canopy provides an active surface which can catalyze chemical conversion. This hypothesis is supported by observation of consistent flux patterns at multiple different sites in the US and by a controlled ISOPOOH fumigation experiment of a plant in an enclosure chamber. In the chamber, we observe transformation of ISOPOOH to MVK+MAC on leaf surfaces even under dark conditions when the stomata are closed.

Transfer behavior of odorous pollutants in wastewater sludge system under typical chemical conditioning processes for dewaterability enhancement.

PubMed

Gao, Hongyu; Zhang, Weijun; Song, Zhenzhen; Yang, Xiaofang; Yang, Lian; Cao, Mengdi; Wang, Dongsheng; Liao, Guiying

2017-06-13

Chemical conditioning has been used for enhancing wastewater sludge dewaterability for many years, but the characteristics of odorous pollutants emission in sludge conditioning were still unclear. In this work, the transfer behavior of different odorous pollutants between air, liquid and solid phases under typical chemical conditioning processes for high-pressure dewatering was systematically investigated. The results indicated that that besides hydrogen sulfide (H 2 S) and ammonia (NH 3 ), 21 kinds of volatile organic contaminants (VOCs) were identified and quantified by gas chromatography-mass spectrometry (GC-MS), while the concentrations and composition of odorous pollutants varied greatly for different conditioning processes. VOCs were composed by three main constituents including benzenes, halogeno benzene and hydrocarbons. According to mass balance analysis, about 50% of VOCs adsorbed within sludge extracellular polymeric substances (EPS) fraction. Since EPS was damaged and/or flocculation in different chemical conditioning processes, VOCs distributed in solid phase transformed into liquid phase and then released into air. The discrepancies in mass of odorous pollutants before and after chemical conditioning were likely to be related to chemical conversion under acidification, oxidation and precipitation in the presence of ferric ions.

Analysis of medium-BTU gasification condensates, June 1985-June 1986

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliott, D.C.

1987-05-01

This report provides the final results of chemical and physical analysis of condensates from biomass gasification systems which are part of the US Department of Energy Biomass Thermochemical Conversion Program. The work described in detail in this report involves extensive analysis of condensates from four medium-BTU gasifiers. The analyses include elemental analysis, ash, moisture, heating value, density, specific chemical analysis, ash, moisture, heating value, density, specific chemical analysis (gas chromatography/mass spectrometry, infrared spectrophotometry, Carbon-13 nuclear magnetic resonance spectrometry) and Ames Assay. This work was an extension of a broader study earlier completed of the condensates of all the gasifers andmore » pyrolyzers in the Biomass Thermochemical Conversion Program. The analytical data demonstrates the wide range of chemical composition of the organics recoverd in the condensates and suggests a direct relationship between operating temperature and chemical composition of the condensates. A continuous pathway of thermal degradation of the tar components as a function of temperature is proposed. Variations in the chemical composition of the organic in the tars are reflected in the physical properties of tars and phase stability in relation to water in the condensate. The biological activity appears to be limited to the tars produced at high temperatures as a result of formation of polycyclic aromatic hydrocarbons in high concentrations. Future studies of the time/temperature relationship to tar composition and the effect of processing atmosphere should be undertaken. Further processing of the condensates either as wastewater treatment or upgrading of the organics to useful products is also recommended. 15 refs., 4 figs., 4 tabs.« less

EDITORIAL: Non-thermal plasma-assisted fuel conversion for green chemistry Non-thermal plasma-assisted fuel conversion for green chemistry

NASA Astrophysics Data System (ADS)

Nozaki, Tomohiro; Gutsol, Alexander

2011-07-01

This special issue is based on the symposium on Non-thermal Plasma Assisted Fuel Conversion for Green Chemistry, a part of the 240th ACS National Meeting & Exposition held in Boston, MA, USA, 22-26 August 2010. Historically, the Division of Fuel Chemistry of the American Chemical Society (ACS) has featured three plasma-related symposia since 2000, and has launched special issues in Catalysis Today on three occasions: 'Catalyst Preparation using Plasma Technologies', Fall Meeting, Washington DC, USA, 2000. Special issue in Catalysis Today 72 (3-4) with 12 peer-reviewed articles. 'Plasma Technology and Catalysis', Spring Meeting, New Orleans, LA, USA, 2003. Special issue in Catalysis Today 89 (1-2) with more than 30 peer-reviewed articles. 'Utilization of Greenhouse Gases II' (partly focused on plasma-related technologies), Spring Meeting, Anaheim, CA, USA, 2004. Special issue in Catalysis Today 98 (4) with 25 peer-reviewed articles. This time, selected presentations are published in this Journal of Physics D: Applied Physics special issue. An industrial material and energy conversion technology platform is established on thermochemical processes including various catalytic reactions. Existing industry-scale technology is already well established; nevertheless, further improvement in energy efficiency and material saving has been continuously demanded. Drastic reduction of CO2 emission is also drawing keen attention with increasing recognition of energy and environmental issues. Green chemistry is a rapidly growing research field, and frequently highlights renewable bioenergy, bioprocesses, solar photocatalysis of water splitting, and regeneration of CO2 into useful chemicals. We would also like to emphasize 'plasma catalysis' of hydrocarbon resources as an important part of the innovative next-generation green technologies. The peculiarity of non-thermal plasma is that it can generate reactive species almost independently of reaction temperature. Plasma-generated reactive species are used to initiate chemical reactions at unexpectedly lower temperatures than conventional thermochemical reactions, leading to non-equilibrium product distribution or creating unconventional reaction pathways. When non-thermal plasma is combined with catalysts, a synergistic effect is frequently observed. Such unique properties of non-thermal plasma are expected to contribute excellent control over process parameters that meet the need for energy saving, environment protection, and material preservation. This special issue consists of eleven peer-reviewed papers including two invited publications. Professors Alexander Fridman and Alexander Rabinovich from Drexel University, and Dr Gutsol from the Chevron Energy Technology Company present a critical review of various industry-oriented practical plasma fuel conversion processes. Professor Richard Mallinson from University of Oklahoma describes his recent project on E85 (85%-ethanol/15%-gasoline) upgrading using non-thermal plasma and catalyst hybrid reactor, and highlights the synergistic effect on fuel conversion processes. Other papers focus on plasma/catalyst hybrid reactions for methane dry (CO2) reforming, plasma synthesis of carbon suboxide polymer from CO, the gas-to-liquid (GTL) process using a non-thermal plasma-combined micro-chemical reactor, and molecular beam characterization of plasma-generated reactive species. Much research regarding plasma catalysis is ongoing worldwide, but there is plenty of room for further development of plasma fuel processing, which could eventually provide a viable and flexible solution in future energy and material use. Finally, we would like to thank all symposium participants for their active discussion. We appreciate the sponsorship of the Division of Fuel Chemistry of the American Chemical Society. We express special thanks to the program chair of the Fuel Chemistry Division, Professor Chang-jun Liu at Tianjin University, for his dedication to the success of the symposium. We particularly express our appreciation to the Editorial Board of Journal of Physics D: Applied Physics for publication of the special issue.

Burning--Gravitational, Chemical, and Nuclear.

ERIC Educational Resources Information Center

Jones, Goronwy Tudor

1991-01-01

Energy problems that incorporate power generation in hydroelectric, fossil-fuel burning, and nuclear power stations are presented. The burning process and the energy released are discussed. Practice problems and solutions, a summary of various energy units and conversion factors, and lists of thought-provoking energies and powers are included. (KR)

Molecular characterization of biochars and their influence on microbiological properties of soil

USDA-ARS?s Scientific Manuscript database

The composition and surface chemistry of carbon rich biochar materials is highly uncertain and believed to change with feedstock and biomass conversion process. The tentative connection between the biochar surface chemical properties and their influence on microbially mediated mineralization of C, N...

Surfactant-Assisted Coal Liquefaction

NASA Technical Reports Server (NTRS)

Hickey, Gregory S.; Sharma, Pramod K.

1993-01-01

Obtaining liquid fuels from coal which are economically competitive with those obtained from petroleum based sources is a significant challenge for the researcher as well as the chemical industry. Presently, the economics of coal liquefaction are not favorable because of relatively intense processing conditions (temperatures of 430 degrees C and pressures of 2200 psig), use of a costly catalyst, and a low quality product slate of relatively high boiling fractions. The economics could be made more favorable by achieving adequate coal conversions at less intense processing conditions and improving the product slate. A study has been carried out to examine the effect of a surfactant in reducing particle agglomeration and improving hydrodynamics in the coal liquefaction reactor to increase coal conversions...

Hybrid photosynthesis-powering biocatalysts with solar energy captured by inorganic devices.

PubMed

Zhang, Tian; Tremblay, Pier-Luc

2017-01-01

The biological reduction of CO 2 driven by sunlight via photosynthesis is a crucial process for life on earth. However, the conversion efficiency of solar energy to biomass by natural photosynthesis is low. This translates in bioproduction processes relying on natural photosynthesis that are inefficient energetically. Recently, hybrid photosynthetic technologies with the potential of significantly increasing the efficiency of solar energy conversion to products have been developed. In these systems, the reduction of CO 2 into biofuels or other chemicals of interest by biocatalysts is driven by solar energy captured with inorganic devices such as photovoltaic cells or photoelectrodes. Here, we explore hybrid photosynthesis and examine the strategies being deployed to improve this biotechnology.

Closed-Loop Multitarget Optimization for Discovery of New Emulsion Polymerization Recipes

PubMed Central

2015-01-01

Self-optimization of chemical reactions enables faster optimization of reaction conditions or discovery of molecules with required target properties. The technology of self-optimization has been expanded to discovery of new process recipes for manufacture of complex functional products. A new machine-learning algorithm, specifically designed for multiobjective target optimization with an explicit aim to minimize the number of “expensive” experiments, guides the discovery process. This “black-box” approach assumes no a priori knowledge of chemical system and hence particularly suited to rapid development of processes to manufacture specialist low-volume, high-value products. The approach was demonstrated in discovery of process recipes for a semibatch emulsion copolymerization, targeting a specific particle size and full conversion. PMID:26435638

75 FR 41505 - National Center for Environmental Health/Agency for Toxic Substances and Disease Registry (NCEH...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-16

...; Notice of National Conversation on Public Health and Chemical Exposures Leadership Council Meeting Time... is the fifth meeting of the National Conversation on Public Health and Chemical Exposures Leadership... Leadership Council provides overall guidance to the National Conversation project and is responsible for...

Polyelectrolyte/Graphene Oxide Barrier Film for Flexible OLED.

PubMed

Yang, Seung-Yeol; Park, Jongwhan; Kim, Yong-Seog

2015-10-01

Ultra-thin flexible nano-composite barrier layer consists of graphene oxide and polyelectrolyte was prepared using the layer-by-layer processing method. Microstructures of the barrier layer was optimized via modifying coating conditions and inducing chemical reactions. Although the barrier layer consists of hydrophilic polyelectrolyte was not effective in blocking the water vapor permeation, the chemical reduction of graphene oxide as well as conversion of polyelectrolyte to hydrophobic nature were very effective in reducing the permeation.

Effect of biogenic fermentation impurities on lactic acid hydrogenation to propylene glycol.

PubMed

Zhang, Zhigang; Jackson, James E; Miller, Dennis J

2008-09-01

The effect of residual impurities from glucose fermentation to lactic acid (LA) on subsequent ruthenium-catalyzed hydrogenation of LA to propylene glycol (PG) is examined. Whereas refined LA feed exhibits stable conversion to PG over carbon-supported ruthenium catalyst in a trickle bed reactor, partially refined LA from fermentation shows a steep decline in PG production over short (<40 h) reaction times followed by a further slow decay in performance. Addition of model impurities to refined LA has varying effects: organic acids, sugars, or inorganic salts have little effect on conversion; alanine, a model amino acid, results in a strong but reversible decline in conversion via competitive adsorption between alanine and LA on the Ru surface. The sulfur-containing amino acids cysteine and methionine irreversibly poison the catalyst for LA conversion. Addition of 0.1 wt% albumin as a model protein leads to slow decline in rate, consistent with pore plugging or combined pore plugging and poisoning of the Ru surface. This study points to the need for integrated design and operation of biological processes and chemical processes in the biorefinery in order to make efficient conversion schemes viable.

Recent progress in the development of solid catalysts for biomass conversion into high value-added chemicals

PubMed Central

Hara, Michikazu; Nakajima, Kiyotaka; Kamata, Keigo

2015-01-01

In recent decades, the substitution of non-renewable fossil resources by renewable biomass as a sustainable feedstock has been extensively investigated for the manufacture of high value-added products such as biofuels, commodity chemicals, and new bio-based materials such as bioplastics. Numerous solid catalyst systems for the effective conversion of biomass feedstocks into value-added chemicals and fuels have been developed. Solid catalysts are classified into four main groups with respect to their structures and substrate activation properties: (a) micro- and mesoporous materials, (b) metal oxides, (c) supported metal catalysts, and (d) sulfonated polymers. This review article focuses on the activation of substrates and/or reagents on the basis of groups (a)–(d), and the corresponding reaction mechanisms. In addition, recent progress in chemocatalytic processes for the production of five industrially important products (5-hydroxymethylfurfural, lactic acid, glyceraldehyde, 1,3-dihydroxyacetone, and furan-2,5-dicarboxylic acid) as bio-based plastic monomers and their intermediates is comprehensively summarized. PMID:27877800

Recent progress in the development of solid catalysts for biomass conversion into high value-added chemicals.

PubMed

Hara, Michikazu; Nakajima, Kiyotaka; Kamata, Keigo

2015-06-01

In recent decades, the substitution of non-renewable fossil resources by renewable biomass as a sustainable feedstock has been extensively investigated for the manufacture of high value-added products such as biofuels, commodity chemicals, and new bio-based materials such as bioplastics. Numerous solid catalyst systems for the effective conversion of biomass feedstocks into value-added chemicals and fuels have been developed. Solid catalysts are classified into four main groups with respect to their structures and substrate activation properties: (a) micro- and mesoporous materials, (b) metal oxides, (c) supported metal catalysts, and (d) sulfonated polymers. This review article focuses on the activation of substrates and/or reagents on the basis of groups (a)-(d), and the corresponding reaction mechanisms. In addition, recent progress in chemocatalytic processes for the production of five industrially important products (5-hydroxymethylfurfural, lactic acid, glyceraldehyde, 1,3-dihydroxyacetone, and furan-2,5-dicarboxylic acid) as bio-based plastic monomers and their intermediates is comprehensively summarized.

Recent progress in the development of solid catalysts for biomass conversion into high value-added chemicals

NASA Astrophysics Data System (ADS)

Hara, Michikazu; Nakajima, Kiyotaka; Kamata, Keigo

2015-06-01

In recent decades, the substitution of non-renewable fossil resources by renewable biomass as a sustainable feedstock has been extensively investigated for the manufacture of high value-added products such as biofuels, commodity chemicals, and new bio-based materials such as bioplastics. Numerous solid catalyst systems for the effective conversion of biomass feedstocks into value-added chemicals and fuels have been developed. Solid catalysts are classified into four main groups with respect to their structures and substrate activation properties: (a) micro- and mesoporous materials, (b) metal oxides, (c) supported metal catalysts, and (d) sulfonated polymers. This review article focuses on the activation of substrates and/or reagents on the basis of groups (a)-(d), and the corresponding reaction mechanisms. In addition, recent progress in chemocatalytic processes for the production of five industrially important products (5-hydroxymethylfurfural, lactic acid, glyceraldehyde, 1,3-dihydroxyacetone, and furan-2,5-dicarboxylic acid) as bio-based plastic monomers and their intermediates is comprehensively summarized.

Multiscale Mathematics for Biomass Conversion to Renewable Hydrogen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plechac, Petr

2016-03-01

The overall objective of this project was to develop multiscale models for understanding and eventually designing complex processes for renewables. To the best of our knowledge, our work is the first attempt at modeling complex reacting systems, whose performance relies on underlying multiscale mathematics and developing rigorous mathematical techniques and computational algorithms to study such models. Our specific application lies at the heart of biofuels initiatives of DOE and entails modeling of catalytic systems, to enable economic, environmentally benign, and efficient conversion of biomass into either hydrogen or valuable chemicals.

Particle size effect of redox reactions for Co species supported on silica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chotiwan, Siwaruk; Tomiga, Hiroki; Katagiri, Masaki

Conversions of chemical states during redox reactions of two silica-supported Co catalysts, which were prepared by the impregnation method, were evaluated by using an in situ XAFS technique. The addition of citric acid into the precursor solution led to the formation on silica of more homogeneous and smaller Co particles, with an average diameter of 4 nm. The supported Co{sub 3}O{sub 4} species were reduced to metallic Co via the divalent CoO species during a temperature-programmed reduction process. The reduced Co species were quantitatively oxidized with a temperature-programmed oxidation process. The higher observed reduction temperature of the smaller CoO particlesmore » and the lower observed oxidation temperature of the smaller metallic Co particles were induced by the higher dispersion of the Co oxide species, which apparently led to a stronger interaction with supporting silica. The redox temperature between CoO and Co{sub 3}O{sub 4} was found to be independent of the particle size. - Graphical abstract: Chemical state conversions of SiO{sub 2}-supported Co species and the particle size effect have been analyzed by means of in situ XAFS technique. The small CoO particles have endurance against the reduction and exist in a wide temperature range. Display Omitted - Highlights: • The conversions of the chemical state of supported Co species during redox reaction are evaluated. • In operando XAFS technique were applied to measure redox properties of small Co particles. • A small particle size affects to the redox temperatures of cobalt catalysts.« less

The conversion process of hydrocarbon hydrates into CO2 hydrates and vice versa: thermodynamic considerations.

PubMed

Schicks, J M; Luzi, M; Beeskow-Strauch, B

2011-11-24

Microscopy, confocal Raman spectroscopy and powder X-ray diffraction (PXRD) were used for in situ investigations of the CO(2)-hydrocarbon exchange process in gas hydrates and its driving forces. The study comprises the exposure of simple structure I CH(4) hydrate and mixed structure II CH(4)-C(2)H(6) and CH(4)-C(3)H(8) hydrates to gaseous CO(2) as well as the reverse reaction, i.e., the conversion of CO(2)-rich structure I hydrate into structure II mixed hydrate. In the case of CH(4)-C(3)H(8) hydrates, a conversion in the presence of gaseous CO(2) from a supposedly more stable structure II hydrate to a less stable structure I CO(2)-rich hydrate was observed. PXRD data show that the reverse process requires longer initiation times, and structural changes seem to be less complete. Generally, the exchange process can be described as a decomposition and reformation process, in terms of a rearrangement of molecules, and is primarily induced by the chemical potential gradient between hydrate phase and the provided gas phase. The results show furthermore the dependency of the conversion rate on the surface area of the hydrate phase, the thermodynamic stability of the original and resulting hydrate phase, as well as the mobility of guest molecules and formation kinetics of the resulting hydrate phase.

Low temperature aqueous desulfurization of coal

DOEpatents

Slegeir, W.A.; Healy, F.E.; Sapienza, R.S.

1985-04-18

This invention describes a chemical process for desulfurizing coal, especially adaptable to the treatment of coal-water slurries, at temperatures as low as ambient, comprising treating the coal with aqueous titanous chloride whereby hydrogen sulfide is liberated and the desulfurized coal is separated with the conversion of titanous chloride to titanium oxides.

Low temperature aqueous desulfurization of coal

DOEpatents

Slegeir, William A.; Healy, Francis E.; Sapienza, Richard S.

1985-01-01

This invention describes a chemical process for desulfurizing coal, especially adaptable to the treatment of coal-water slurries, at temperatures as low as ambient, comprising treating the coal with aqueous titanous chloride whereby hydrogen sulfide is liberated and the desulfurized coal is separated with the conversion of titanous chloride to titanium oxides.

Pelletizing properties of torrefied spruce

Treesearch

Wolfgang Stelte; Craig Clemons; Jens K. Holm; Anand R. Sanadi; Jesper Ahrenfeldt; Lei Shang; Ulrik B. Henriksen

2011-01-01

Torrefaction is a thermo-chemical conversion process improving the handling, storage and combustion properties of wood. To save storage space and transportation costs, it can be compressed into fuel pellets of high physical and energetic density. The resulting pellets are relatively resistant to moisture uptake, microbiological decay and easy to comminute into small...

IN SITU BIOREMEDIATION IN A LANDFILL: HOLDING TIME STUDY OF LEACHATE CHEMICAL AND MICROBIAL PARAMETERS

EPA Science Inventory

Processing and analyzing solid waste samples from large and costly sampling events in a timely manner is often difficult. As part of a Cooperative Research and Development Agreement (CRADA), the U.S. EPA and Waste Management Inc. (WMI) are investigating the conversion of landfill...

COPROCESSING OF FOSSIL FUELS AND BIOMASS FOR CO2 EMISSION REDUCTION IN THE TRANSPORTATION SECTOR

EPA Science Inventory

The paper discusses an evaluation of the Hydrocarb process for conversion of carbonaceous raw material to clean carbon and methanol products. hese products are valuable in the market either as fuel or as chemical commodities. s fuel, methanol and carbon can be used economically, ...

Catalytic oxidation of biorefinery lignin to value-added chemicals to support sustainable biofuel production.

PubMed

Ma, Ruoshui; Xu, Yan; Zhang, Xiao

2015-01-01

Transforming plant biomass to biofuel is one of the few solutions that can truly sustain mankind's long-term needs for liquid transportation fuel with minimized environmental impact. However, despite decades of effort, commercial development of biomass-to-biofuel conversion processes is still not an economically viable proposition. Identifying value-added co-products along with the production of biofuel provides a key solution to overcoming this economic barrier. Lignin is the second most abundant component next to cellulose in almost all plant biomass; the emerging biomass refinery industry will inevitably generate an enormous amount of lignin. Development of selective biorefinery lignin-to-bioproducts conversion processes will play a pivotal role in significantly improving the economic feasibility and sustainability of biofuel production from renewable biomass. The urgency and importance of this endeavor has been increasingly recognized in the last few years. This paper reviews state-of-the-art oxidative lignin depolymerization chemistries employed in the papermaking process and oxidative catalysts that can be applied to biorefinery lignin to produce platform chemicals including phenolic compounds, dicarboxylic acids, and quinones in high selectivity and yield. The potential synergies of integrating new catalysts with commercial delignification chemistries are discussed. We hope the information will build on the existing body of knowledge to provide new insights towards developing practical and commercially viable lignin conversion technologies, enabling sustainable biofuel production from lignocellulosic biomass to be competitive with fossil fuel. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

MSU-Northern Bio-Energy Center of Excellence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kegel, Greg; Alcorn-Windy Boy, Jessica; Abedin, Md. Joynal

2014-09-30

MSU-Northern established the Bio-Energy Center (the Center) into a Regional Research Center of Excellence to address the obstacles concerning biofuels, feedstock, quality, conversion process, economic viability and public awareness. The Center built its laboratories and expertise in order to research and support product development and commercialization for the bio-energy industry in our region. The Center wanted to support the regional agricultural based economy by researching biofuels based on feedstock’s that can be grown in our region in an environmentally responsible manner. We were also interested in any technology that will improve the emissions and fuel economy performance of heavy dutymore » diesel engines. The Center had a three step approach to accomplish these goals: 1. Enhance the Center’s research and testing capabilities 2. Develop advanced biofuels from locally grown agricultural crops. 3. Educate and outreach for public understanding and acceptance of new technology. The Center was very successful in completing the tasks as outlined in the project plan. Key successes include discovering and patenting a new chemical conversion process for converting camelina oil to jet fuel, as well as promise in developing a heterogeneous Grubs catalyst to support the new chemical conversion process. The Center also successfully fragmented and deoxygenated naturally occurring lignin with a Ni-NHC catalyst, showing promise for further exploration of using lignin for fuels and fuel additives. This would create another value-added product for lignin that can be sourced from beetle kill trees or waste products from cellulose ethanol fuel facilities.« less

Chemical interaction matrix between reagents in a Purex based process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brahman, R.K.; Hennessy, W.P.; Paviet-Hartmann, P.

2008-07-01

The United States Department of Energy (DOE) is the responsible entity for the disposal of the United States excess weapons grade plutonium. DOE selected a PUREX-based process to convert plutonium to low-enriched mixed oxide fuel for use in commercial nuclear power plants. To initiate this process in the United States, a Mixed Oxide (MOX) Fuel Fabrication Facility (MFFF) is under construction and will be operated by Shaw AREVA MOX Services at the Savannah River Site. This facility will be licensed and regulated by the U.S. Nuclear Regulatory Commission (NRC). A PUREX process, similar to the one used at La Hague,more » France, will purify plutonium feedstock through solvent extraction. MFFF employs two major process operations to manufacture MOX fuel assemblies: (1) the Aqueous Polishing (AP) process to remove gallium and other impurities from plutonium feedstock and (2) the MOX fuel fabrication process (MP), which processes the oxides into pellets and manufactures the MOX fuel assemblies. The AP process consists of three major steps, dissolution, purification, and conversion, and is the center of the primary chemical processing. A study of process hazards controls has been initiated that will provide knowledge and protection against the chemical risks associated from mixing of reagents over the life time of the process. This paper presents a comprehensive chemical interaction matrix evaluation for the reagents used in the PUREX-based process. Chemical interaction matrix supplements the process conditions by providing a checklist of any potential inadvertent chemical reactions that may take place. It also identifies the chemical compatibility/incompatibility of the reagents if mixed by failure of operations or equipment within the process itself or mixed inadvertently by a technician in the laboratories. (aut0010ho.« less

Coordination nano-space as stage of hydrogen ortho–para conversion

PubMed Central

Kosone, Takashi; Hori, Akihiro; Nishibori, Eiji; Kubota, Yoshiki; Mishima, Akio; Ohba, Masaaki; Tanaka, Hiroshi; Kato, Kenichi; Kim, Jungeun; Real, José Antonio; Kitagawa, Susumu; Takata, Masaki

2015-01-01

The ability to design and control properties of nano-sized space in porous coordination polymers (PCPs) would provide us with an ideal stage for fascinating physical and chemical phenomena. We found an interconversion of nuclear-spin isomers for hydrogen molecule H2 adsorbed in a Hofmann-type PCP, {Fe(pz)[Pd(CN)4]} (pz=pyrazine), by the temperature dependence of Raman spectra. The ortho (o)–para (p) conversion process of H2 is forbidden for an isolated molecule. The charge density study using synchrotron radiation X-ray diffraction reveals the electric field generated in coordination nano-space. The present results corroborate similar findings observed on different systems and confirm that o–p conversion can occur on non-magnetic solids and that electric field can induce the catalytic hydrogen o–p conversion. PMID:26587262

Conversion of Nuclear Waste to Molten Glass: Cold-Cap Reactions in Crucible Tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Kai; Hrma, Pavel; Rice, Jarrett A.

2016-05-23

The feed-to-glass conversion, which comprises complex chemical reactions and phase transitions, occurs in the cold-cap zone during nuclear waste vitrification. Knowledge of the chemistry and physics of feed-to-glass conversion will help us control the conversion path by changing the melter feed makeup to maximize the glass production rate. To investigate the conversion process, we analyzed heat-treated samples of a simulated high-level waste feed using X-ray diffraction, electron probe microanalysis – wavelength dispersive X-ray spectroscopy, leaching tests, and residual anion analysis. Feed dehydration, gas evolution, and borate phase formation occurred at temperatures below 700 °C before the emerging glass-forming melt wasmore » completely connected. Above 800 °C, intermediate aluminosilicate phases and quartz particles were gradually dissolving in the continuous borosilicate melt, which expanded into transient foam. Knowledge of the chemistry and physics of feed-to-glass conversion will help us control the conversion path by changing the melter feed makeup to maximize the glass production rate.« less

Chemoselective catalytic conversion of glycerol as a biorenewable source to valuable commodity chemicals.

PubMed

Zhou, Chun-Hui Clayton; Beltramini, Jorge N; Fan, Yong-Xian; Lu, G Q Max

2008-03-01

New opportunities for the conversion of glycerol into value-added chemicals have emerged in recent years as a result of glycerol's unique structure, properties, bioavailability, and renewability. Glycerol is currently produced in large amounts during the transesterification of fatty acids into biodiesel and as such represents a useful by-product. This paper provides a comprehensive review and critical analysis on the different reaction pathways for catalytic conversion of glycerol into commodity chemicals, including selective oxidation, selective hydrogenolysis, selective dehydration, pyrolysis and gasification, steam reforming, thermal reduction into syngas, selective transesterification, selective etherification, oligomerization and polymerization, and conversion of glycerol into glycerol carbonate.

Efficient co-conversion process of chicken manure into protein feed and organic fertilizer by Hermetia illucens L. (Diptera: Stratiomyidae) larvae and functional bacteria.

PubMed

Xiao, Xiaopeng; Mazza, Lorenzo; Yu, Yongqiang; Cai, Minmin; Zheng, Longyu; Tomberlin, Jeffery K; Yu, Jeffrey; van Huis, Arnold; Yu, Ziniu; Fasulo, Salvatore; Zhang, Jibin

2018-07-01

A chicken manure management process was carried out through co-conversion of Hermetia illucens L. larvae (BSFL) with functional bacteria for producing larvae as feed stuff and organic fertilizer. Thirteen days co-conversion of 1000 kg of chicken manure inoculated with one million 6-day-old BSFL and 10 9  CFU Bacillus subtilis BSF-CL produced aging larvae, followed by eleven days of aerobic fermentation inoculated with the decomposing agent to maturity. 93.2 kg of fresh larvae were harvested from the B. subtilis BSF-CL-inoculated group, while the control group only harvested 80.4 kg of fresh larvae. Chicken manure reduction rate of the B. subtilis BSF-CL-inoculated group was 40.5%, while chicken manure reduction rate of the control group was 35.8%. The weight of BSFL increased by 15.9%, BSFL conversion rate increased by 12.7%, and chicken manure reduction rate increased by 13.4% compared to the control (no B. subtilis BSF-CL). The residue inoculated with decomposing agent had higher maturity (germination index >92%), compared with the no decomposing agent group (germination index ∼86%). The activity patterns of different enzymes further indicated that its production was more mature and stable than that of the no decomposing agent group. Physical and chemical production parameters showed that the residue inoculated with the decomposing agent was more suitable for organic fertilizer than the no decomposing agent group. Both, the co-conversion of chicken manure by BSFL with its synergistic bacteria and the aerobic fermentation with the decomposing agent required only 24 days. The results demonstrate that co-conversion process could shorten the processing time of chicken manure compared to traditional compost process. Gut bacteria could enhance manure conversion and manure reduction. We established efficient manure co-conversion process by black soldier fly and bacteria and harvest high value-added larvae mass and biofertilizer. Copyright © 2018 Elsevier Ltd. All rights reserved.

Woody biomass: Niche position as a source of sustainable renewable chemicals and energy and kinetics of hot-water extraction/hydrolysis.

PubMed

Liu, Shijie

2010-01-01

The conversion of biomass to chemicals and energy is imperative to sustaining our way of life as known to us today. Fossil chemical and energy sources are traditionally regarded as wastes from a distant past. Petroleum, natural gas, and coal are not being regenerated in a sustainable manner. However, biomass sources such as algae, grasses, bushes and forests are continuously being replenished. Woody biomass represents the most abundant and available biomass source. Woody biomass is a reliably sustainable source of chemicals and energy that could be replenished at a rate consistent with our needs. The biorefinery is a concept describing the collection of processes used to convert biomass to chemicals and energy. Woody biomass presents more challenges than cereal grains for conversion to platform chemicals due to its stereochemical structures. Woody biomass can be thought of as comprised of at least four components: extractives, hemicellulose, lignin and cellulose. Each of these four components has a different degree of resistance to chemical, thermal and biological degradation. The biorefinery concept proposed at ESF (State University of New York - College of Environmental Science and Forestry) aims at incremental sequential deconstruction, fractionation/conversion of woody biomass to achieve efficient separation of major components. The emphasis of this work is on the kinetics of hot-water extraction, filling the gap in the fundamental understanding, linking engineering developments, and completing the first step in the biorefinery processes. This first step removes extractives and hemicellulose fractions from woody biomass. While extractives and hemicellulose are largely removed in the extraction liquor, cellulose and lignin largely remain in the residual woody structure. Xylo-oligomers and acetic acid in the extract are the major components having the greatest potential value for development. Extraction/hydrolysis involves at least 16 general reactions that could be divided into four categories: adsorption of proton onto woody biomass, hydrolysis reactions on the woody biomass surface, dissolution of soluble substances into the extraction liquor, and hydrolysis and dehydration decomposition in the extraction liquor. The extraction/hydrolysis rates are significantly simplified when the reactivity of all the intermonomer bonds are regarded as identical within each macromolecule, and the overall reactivity are identical for all the extractable macromolecules on the surface. A pseudo-first order extraction rate expression has been derived based on concentrations in monomer units. The reaction rate constant is however lower at the beginning of the extraction than that towards the end of the extraction. Furthermore, the H-factor and/or severity factor can be applied to lump the effects of temperature and residence time on the extraction process, at least for short times. This provides a means to control and optimize the performance of the extraction process effectively. Copyright 2010 Elsevier Inc. All rights reserved.

Shaking Alone Induces De Novo Conversion of Recombinant Prion Proteins to β-Sheet Rich Oligomers and Fibrils

PubMed Central

Ladner-Keay, Carol L.; Griffith, Bethany J.; Wishart, David S.

2014-01-01

The formation of β-sheet rich prion oligomers and fibrils from native prion protein (PrP) is thought to be a key step in the development of prion diseases. Many methods are available to convert recombinant prion protein into β-sheet rich fibrils using various chemical denaturants (urea, SDS, GdnHCl), high temperature, phospholipids, or mildly acidic conditions (pH 4). Many of these methods also require shaking or another form of agitation to complete the conversion process. We have identified that shaking alone causes the conversion of recombinant PrP to β-sheet rich oligomers and fibrils at near physiological pH (pH 5.5 to pH 6.2) and temperature. This conversion does not require any denaturant, detergent, or any other chemical cofactor. Interestingly, this conversion does not occur when the water-air interface is eliminated in the shaken sample. We have analyzed shaking-induced conversion using circular dichroism, resolution enhanced native acidic gel electrophoresis (RENAGE), electron microscopy, Fourier transform infrared spectroscopy, thioflavin T fluorescence and proteinase K resistance. Our results show that shaking causes the formation of β-sheet rich oligomers with a population distribution ranging from octamers to dodecamers and that further shaking causes a transition to β-sheet fibrils. In addition, we show that shaking-induced conversion occurs for a wide range of full-length and truncated constructs of mouse, hamster and cervid prion proteins. We propose that this method of conversion provides a robust, reproducible and easily accessible model for scrapie-like amyloid formation, allowing the generation of milligram quantities of physiologically stable β-sheet rich oligomers and fibrils. These results may also have interesting implications regarding our understanding of prion conversion and propagation both within the brain and via techniques such as protein misfolding cyclic amplification (PMCA) and quaking induced conversion (QuIC). PMID:24892647

Enhanced energy conversion efficiency from high strength synthetic organic wastewater by sequential dark fermentative hydrogen production and algal lipid accumulation.

PubMed

Ren, Hong-Yu; Liu, Bing-Feng; Kong, Fanying; Zhao, Lei; Xing, Defeng; Ren, Nan-Qi

2014-04-01

A two-stage process of sequential dark fermentative hydrogen production and microalgal cultivation was applied to enhance the energy conversion efficiency from high strength synthetic organic wastewater. Ethanol fermentation bacterium Ethanoligenens harbinense B49 was used as hydrogen producer, and the energy conversion efficiency and chemical oxygen demand (COD) removal efficiency reached 18.6% and 28.3% in dark fermentation. Acetate was the main soluble product in dark fermentative effluent, which was further utilized by microalga Scenedesmus sp. R-16. The final algal biomass concentration reached 1.98gL(-1), and the algal biomass was rich in lipid (40.9%) and low in protein (23.3%) and carbohydrate (11.9%). Compared with single dark fermentation stage, the energy conversion efficiency and COD removal efficiency of two-stage system remarkably increased 101% and 131%, respectively. This research provides a new approach for efficient energy production and wastewater treatment using a two-stage process combining dark fermentation and algal cultivation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cogeneration Technology Alternatives Study (CTAS). Volume 5: Cogeneration systems results

NASA Technical Reports Server (NTRS)

Gerlaugh, H. E.; Hall, E. W.; Brown, D. H.; Priestley, R. R.; Knightly, W. F.

1980-01-01

The use of various advanced energy conversion systems is examined and compared with each other and with current technology systems for savings in fuel energy, costs, and emissions in individual plants and on a national level. About fifty industrial processes from the largest energy consuming sectors were used as a basis for matching a similar number of energy conversion systems that are considered as candidate which can be made available by the 1985 to 2000 time period. The sectors considered included food, textiles, lumber, paper, chemicals, petroleum, glass, and primary metals. The energy conversion systems included steam and gas turbines, diesels, thermionics, stirling, closed cycle and steam injected gas turbines, and fuel cells. Fuels considered were coal, both coal and petroleum based residual and distillate liquid fuels, and low Btu gas obtained through the on site gasification of coal. The methodology and results of matching the cogeneration energy conversion systems to approximately 50 industrial processes are described. Results include fuel energy saved, levelized annual energy cost saved, return on investment, and operational factors relative to the noncogeneration base cases.

Combined hydrothermal liquefaction and catalytic hydrothermal gasification system and process for conversion of biomass feedstocks

DOEpatents

Elliott, Douglas C.; Neuenschwander, Gary G.; Hart, Todd R.

2017-09-12

A combined hydrothermal liquefaction (HTL) and catalytic hydrothermal gasification (CHG) system and process are described that convert various biomass-containing sources into separable bio-oils and aqueous effluents that contain residual organics. Bio-oils may be converted to useful bio-based fuels and other chemical feedstocks. Residual organics in HTL aqueous effluents may be gasified and converted into medium-BTU product gases and directly used for process heating or to provide energy.

Sulfide‐ and nitrite‐dependent nitric oxide production in the intestinal tract

PubMed Central

Vermeiren, Joan; Van de Wiele, Tom; Van Nieuwenhuyse, Glynn; Boeckx, Pascal; Verstraete, Willy; Boon, Nico

2012-01-01

Summary In the gut ecosystem, nitric oxide (NO) has been described to have damaging effects on the energy metabolism of colonocytes. Described mechanisms of NO production are microbial reduction of nitrate via nitrite to NO and conversion of l‐arginine by NO synthase. The aim of this study was to investigate whether dietary compounds can stimulate the production of NO by representative cultures of the human intestinal microbiota and whether this correlates to other processes in the intestinal tract. We have found that the addition of a reduced sulfur compound, i.e. cysteine, contributed to NO formation. This increase was ascribed to higher sulfide concentrations generated from cysteine that in turn promoted the chemical conversion of nitrite to NO. The NO release from nitrite was of the order of 4‰ at most. Overall, it was shown that two independent biological processes contribute to the chemical formation of NO in the intestinal tract: (i) the production of sulfide by fermentation of sulfur containing amino acids or reduction of sulfate by sulfate reducing bacteria, and (ii) the reduction of nitrate to nitrite. Our results indicate that dietary thiol compounds in combination with nitrate may contribute to colonocytes damaging processes by promoting NO formation. PMID:22129449

Membranes for Food and Bioproduct Processing

NASA Astrophysics Data System (ADS)

Avram, Alexandru M.

Modified membranes for process intensification in biomass hydrolysis: Production of biofuels and chemicals from lignocellulosic biomass is one of the leading candidates for replacement of petroleum based fuels and chemicals. However, conversion of lignocellulosic biomass into fuels and chemicals is not cost effective compared to the production of fuels and chemicals from crude oil reserves. Some novel and economically feasible approaches involve the use of ionic liquids as solvents or co-solvents, since these show improved solvation capability of cellulose over simple aqueous systems. Membranes offer unique opportunities for process intensification which involves fractionation of the resulting biomass hydrolysate leading to a more efficient and cheaper operation. This research attempts to develop membranes that would usher the economics of the biochemical conversion of lignocellulosic biomass into fuels and chemicals by recycling the expensive ionic liquid. The overall aim of this work is the development of novel membranes with unique surface properties that enable the selective separation of non-reacted cellulose and hydrolysis sugars from ionic liquids. Nanofiltration separation for application in food product engineering: With the advent of the modern, well-informed consumer who has high expectations from the nutritional value of consumed food products, novel approaches are being developed to produce nutrient-enhanced foods and drinks. As a response to the consumer needs, different techniques to recover, concentrate and retain as much as possible of bioactive compounds are being investigated. Membrane technology has the advantage of selective fractionation of food products (e.g. salt removal, removal of bitter-tasting compounds or removal of sugar for sweet taste adjustment), volume reduction, and product recovery at mild conditions. In this work, we use nanofiltration in dead-end and crossflow mode to concentrate polyphenols from blueberry pomace. Blueberry pomace is an overlooked waste product form the juice pressing of blueberries that contains high amounts of health-beneficial antioxidants. We aim at developing a simple, yet efficient membrane process that reduces the amount of water and thus concentrates the amount of polyphenols in the retentate.

Sugarcane-Biorefinery.

PubMed

Vaz, Sílvio

2017-03-17

Concepts such as biorefinery and green chemistry focus on the usage of biomass, as with the oil value chain. However, it can cause less negative impact on the environment. A biorefinery based on sugarcane (Saccharum spp.) as feedstock is an example, because it can integrate into the same physical space, of processes for obtaining biofuels (ethanol), chemicals (from sugars or ethanol), electricity, and heat.The use of sugarcane as feedstock for biorefineries is dictated by its potential to supply sugars, ethanol, natural polymers or macromolecules, organic matter, and other compounds and materials. By means of conversion processes (chemical, biochemical, and thermochemical), sugarcane biomass can be transformed into high-value bioproducts to replace petrochemicals, as a bioeconomy model.

Biorefineries--multi product processes.

PubMed

Kamm, B; Kamm, M

2007-01-01

The development of biorefineries represents the key for access to an integrated production of food, feed, chemicals, materials, goods, and fuels of the future [1]. Biorefineries combine the necessary technologies of the biogenic raw materials with those of intermediates and final products. The main focus is directed at the precursors carbohydrates, lignin, oils, and proteins and the combination between biotechnological and chemical conversion of substances. Currently the lignocellulosic feedstock biorefinery, green biorefinery, whole corn biorefinery, and the so-called two-platform concept are favored in research, development, and industrial implementation.

Chemical Processing in High-Pressure Aqueous Environments. 9. Process Development for Catalytic Gasification of Algae Feedstocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliott, Douglas C.; Hart, Todd R.; Neuenschwander, Gary G.

Through the use of a metal catalyst, gasification of wet algae slurries can be accomplished with high levels of carbon conversion to gas at relatively low temperature (350 C). In a pressurized-water environment (20 MPa), near-total conversion of the organic structure of the algae to gases has been achieved in the presence of a supported ruthenium metal catalyst. The process is essentially steam reforming, as there is no added oxidizer or reagent other than water. In addition, the gas produced is a medium-heating value gas due to the synthesis of high levels of methane, as dictated by thermodynamic equilibrium. Asmore » opposed to earlier work, biomass trace components were removed by processing steps so that they did not cause processing difficulties in the fixed catalyst bed tubular reactor system. As a result, the algae feedstocks, even those with high ash contents, were much more reliably processed. High conversions were obtained even with high slurry concentrations. Consistent catalyst operation in these short-term tests suggested good stability and minimal poisoning effects. High methane content in the product gas was noted with significant carbon dioxide captured in the aqueous byproduct in combination with alkali constituents and the ammonia byproduct derived from proteins in the algae. High conversion of algae to gas products was found with low levels of byproduct water contamination and low to moderate loss of carbon in the mineral separation step.« less

A versatile chemical conversion synthesis of Cu2S nanotubes and the photovoltaic activities for dye-sensitized solar cell

PubMed Central

2014-01-01

A versatile, low-temperature, and low-cost chemical conversion synthesis has been developed to prepare copper sulfide (Cu2S) nanotubes. The successful chemical conversion from ZnS nanotubes to Cu2S ones profits by the large difference in solubility between ZnS and Cu2S. The morphology, structure, and composition of the yielded products have been examined by field-emission scanning electron microscopy, transmission electron microscopy, and X-ray diffraction measurements. We have further successfully employed the obtained Cu2S nanotubes as counter electrodes in dye-sensitized solar cells. The light-to-electricity conversion results show that the Cu2S nanostructures exhibit high photovoltaic conversion efficiency due to the increased surface area and the good electrocatalytical activity of Cu2S. The present chemical route provides a simple way to synthesize Cu2S nanotubes with a high surface area for nanodevice applications. PMID:25246878

Flash Cracking Reactor for Waste Plastic Processing

NASA Technical Reports Server (NTRS)

Timko, Michael T.; Wong, Hsi-Wu; Gonzalez, Lino A.; Broadbelt, Linda; Raviknishan, Vinu

2013-01-01

Conversion of waste plastic to energy is a growing problem that is especially acute in space exploration applications. Moreover, utilization of heavy hydrocarbon resources (wastes, waxes, etc.) as fuels and chemicals will be a growing need in the future. Existing technologies require a trade-off between product selectivity and feedstock conversion. The objective of this work was to maintain high plastic-to-fuel conversion without sacrificing the liquid yield. The developed technology accomplishes this goal with a combined understanding of thermodynamics, reaction rates, and mass transport to achieve high feed conversion without sacrificing product selectivity. The innovation requires a reaction vessel, hydrocarbon feed, gas feed, and pressure and temperature control equipment. Depending on the feedstock and desired product distribution, catalyst can be added. The reactor is heated to the desired tempera ture, pressurized to the desired pressure, and subject to a sweep flow at the optimized superficial velocity. Software developed under this project can be used to determine optimal values for these parameters. Product is vaporized, transferred to a receiver, and cooled to a liquid - a form suitable for long-term storage as a fuel or chemical. An important NASA application is the use of solar energy to convert waste plastic into a form that can be utilized during periods of low solar energy flux. Unlike previous work in this field, this innovation uses thermodynamic, mass transport, and reaction parameters to tune product distribution of pyrolysis cracking. Previous work in this field has used some of these variables, but never all in conjunction for process optimization. This method is useful for municipal waste incinerator operators and gas-to-liquids companies.

Organic microchemical performance of solvent resistant polycarbosilane based microreactor.

PubMed

Yoon, Tae-Ho; Jung, Sang-Hee; Kim, Dong-Pyo

2011-05-01

We report the successful fabrication of preceramic polymer allylhydridopolycarbosilane (AHPCS) derived microchannels with excellent organic solvent resistance and optical transparency via economic imprinting process, followed by UV and post thermal curing process at 160 degrees C for 3 h. The microchemical performance of the fabricated microreactors was evaluated by choosing two model micro chemical reactions under organic solvent conditions; syntheses of 2-aminothiazole in DMF and dimethylpyrazole in THF, and compared with glass-based microreactor having identical dimensions and batch system with analogy. It is clear that AHPCS derived microreactor showed excellent solvent resistance and chemical stability compare with glass derived microreactor made by high cost of photolithography and thermal bonding process. The novel preceramic polymer derived microreactors showed reliable mechanical and chemical stability and conversion yields compare with that of glass derived microreactors, which is very promising for developing an integrated microfluidics by adopting available microstructuring techniques of the polymers.

Black-and-white photographic chemistry: A reference

NASA Technical Reports Server (NTRS)

Walker, E. D. (Compiler)

1986-01-01

This work is intended as a reference of black-and-white photographic chemistry. Included is a basic history of the photographic processes and a complete description of all chemicals used, formulas for the development and fixation process, and associated formulas such as cleaners, hardeners, and toners. The work contains a complete glossary of photographic terms, a trouble-shooting section listing causes and effects regarding photographic film and papers, and various conversion charts.

Process modelling of biomass conversion to biofuels with combined heat and power.

PubMed

Sharma, Abhishek; Shinde, Yogesh; Pareek, Vishnu; Zhang, Dongke

2015-12-01

A process model has been developed to study the pyrolysis of biomass to produce biofuel with heat and power generation. The gaseous and solid products were used to generate heat and electrical power, whereas the bio-oil was stored and supplied for other applications. The overall efficiency of the base case model was estimated for conversion of biomass into useable forms of bio-energy. It was found that the proposed design is not only significantly efficient but also potentially suitable for distributed operation of pyrolysis plants having centralised post processing facilities for production of other biofuels and chemicals. It was further determined that the bio-oil quality improved using a multi-stage condensation system. However, the recycling of flue gases coming from combustor instead of non-condensable gases in the pyrolyzer led to increase in the overall efficiency of the process with degradation of bio-oil quality. Copyright © 2015 Elsevier Ltd. All rights reserved.

Genetically Engineered Materials for Biofuels Production

NASA Astrophysics Data System (ADS)

Raab, Michael

2012-02-01

Agrivida, Inc., is an agricultural biotechnology company developing industrial crop feedstocks for the fuel and chemical industries. Agrivida's crops have improved processing traits that enable efficient, low cost conversion of the crops' cellulosic components into fermentable sugars. Currently, pretreatment and enzymatic conversion of the major cell wall components, cellulose and hemicellulose, into fermentable sugars is the most expensive processing step that prevents widespread adoption of biomass in biofuels processes. To lower production costs we are consolidating pretreatment and enzyme production within the crop. In this strategy, transgenic plants express engineered cell wall degrading enzymes in an inactive form, which can be reactivated after harvest. We have engineered protein elements that disrupt enzyme activity during normal plant growth. Upon exposure to specific processing conditions, the engineered enzymes are converted into their active forms. This mechanism significantly lowers pretreatment costs and enzyme loadings (>75% reduction) below those currently available to the industry.

One‐Step Reforming of CO2 and CH4 into High‐Value Liquid Chemicals and Fuels at Room Temperature by Plasma‐Driven Catalysis

PubMed Central

Wang, Li; Yi, Yanhui; Wu, Chunfei; Guo, Hongchen

2017-01-01

Abstract The conversion of CO2 with CH4 into liquid fuels and chemicals in a single‐step catalytic process that bypasses the production of syngas remains a challenge. In this study, liquid fuels and chemicals (e.g., acetic acid, methanol, ethanol, and formaldehyde) were synthesized in a one‐step process from CO2 and CH4 at room temperature (30 °C) and atmospheric pressure for the first time by using a novel plasma reactor with a water electrode. The total selectivity to oxygenates was approximately 50–60 %, with acetic acid being the major component at 40.2 % selectivity, the highest value reported for acetic acid thus far. Interestingly, the direct plasma synthesis of acetic acid from CH4 and CO2 is an ideal reaction with 100 % atom economy, but it is almost impossible by thermal catalysis owing to the significant thermodynamic barrier. The combination of plasma and catalyst in this process shows great potential for manipulating the distribution of liquid chemical products in a given process. PMID:28842938

Conversion of CO2 to CO using radio-frequency atmospheric pressure plasmas

NASA Astrophysics Data System (ADS)

Foote, Alexander; Dedrick, James; O'Connell, Deborah; North, Michael; Gans, Timo

2016-09-01

Low temperature plasmas can be used for the in situ generation of CO, from relatively non-toxic CO2 . CO is very useful in many industrial chemical processes and so, via low temperature plasmas, CO2, a waste product, can be converted into a valuable chemical. The key challenges in using this method, for CO production, are optimising the energy efficiency, maximising the conversion of CO2 into CO and then separating the CO from the other species produced in the plasma. Very high yields of CO, greater than 90%, have been achieved at atmospheric pressure using argon as a carrier gas with admixtures up to 1.5% with energy efficiencies of up to 4%. The plasma generated in continuous and spatially homogeneous and is driven at a frequency of 40.68 MHz. A zero dimensional global model has also been used to simulate the chemical kinetics of the plasma to determine the dominant dissociation processes and is in good agreement with the experimentally determined yields. The model is used to determine how important a role the vibrational states of CO2 are, in a highly collisional plasma, to the production of CO and there can provide insight into how to improve the energy efficiency and suppress unwanted reactions.

Nanostructured transition metal dichalcogenide electrocatalysts for CO2 reduction in ionic liquid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asadi, M.; Kim, K.; Liu, C.

2016-07-28

Conversion of carbon dioxide (CO2) into fuels is an attractive solution to many energy and environmental challenges. However, the chemical inertness of CO2 renders many electrochemical and photochemical conversion processes inefficient. We report a transition metal dichalcogenide nanoarchitecture for catalytic electrochemical CO2 conversion to carbon monoxide (CO) in an ionic liquid. We found that tungsten diselenide nanoflakes show a current density of 18.95 milliamperes per square centimeter, CO faradaic efficiency of 24%, and CO formation turnover frequency of 0.28 per second at a low overpotential of 54 millivolts. We also applied this catalyst in a light-harvesting artificial leaf platform thatmore » concurrently oxidized water in the absence of any external potential.« less

Continuous Succinic Acid Production by Actinobacillus succinogenes on Xylose-Enriched Hydrolysate

DOE PAGES

Bradfield, Michael F. A.; Mohagheghi, Ali; Salvachua, Davinia; ...

2015-11-14

Bio-manufacturing of high-value chemicals in parallel to renewable biofuels has the potential to dramatically improve the overall economic landscape of integrated lignocellulosic biorefineries. However, this will require the generation of carbohydrate streams from lignocellulose in a form suitable for efficient microbial conversion and downstream processing appropriate to the desired end use, making overall process development, along with selection of appropriate target molecules, crucial to the integrated biorefinery. Succinic acid (SA), a high-value target molecule, can be biologically produced from sugars and has the potential to serve as a platform chemical for various chemical and polymer applications. However, the feasibility ofmore » microbial SA production at industrially relevant productivities and yields from lignocellulosic biorefinery streams has not yet been reported.« less

Design of Stratified Functional Nanoporous Materials for CO 2 Capture and Conversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, J. Karl; Ye, Jingyun

The objective of this project is to develop novel nanoporous materials for CO 2 capture and conversion. The motivation of this work is that capture of CO 2 from flue gas or the atmosphere coupled with catalytic hydrogenation of CO 2 into valuable chemicals and fuels can reduce the net amount of CO 2 in the atmosphere while providing liquid transportation fuels and other commodity chemicals. One approach to increasing the economic viability of carbon capture and conversion is to design a single material that can be used for both the capture and catalytic conversion of CO 2, because suchmore » a material could increase efficiency through process intensification. We have used density functional theory (DFT) methods to design catalytic moieties that can be incorporated into various metal organic framework (MOF) materials. We chose to work with MOFs because they are highly tailorable, can be functionalized, and have been shown to selectively adsorb CO 2 over N 2, which is a requirement for CO 2 capture from flue gas. Moreover, the incorporation of molecular catalytic moieties into MOF, through covalent bonding, produces a heterogeneous catalytic material having activities and selectivities close to those of homogeneous catalysts, but without the draw-backs associated with homogeneous catalysis.« less

Investigation of Redox Metal Oxides for Carbonaceous Fuel Conversion and CO2 Capture

NASA Astrophysics Data System (ADS)

Galinsky, Nathan Lee

The chemical looping combustion (CLC) process uses metal oxides, also referred to as oxygen carriers, in a redox scheme for conversion of carbonaceous fuels into a concentrated stream of CO2 and steam while also producing heat and electricity. The unique redox scheme of CLC allows CO2 capture with minimal energy penalty. The CLC process performance greatly depends on the oxygen carrier that is chosen. To date, more than 1000 oxygen carriers have been developed for chemical-looping processes using metal oxides containing first-row transition metals. Oxygen carriers are typically mixed with an inert ceramic support to improve their overall mechanical stability and recyclability. This study focuses on design of (i) iron oxide oxygen carriers for conversion of gaseous carbonaceous fuels and (ii) development of perovskite CaMnO 3-d with improved stability and redox properties for conversion of solid fuels. Iron oxide is cheap and environmentally benign. However, it suffers from low activity with carbonaceous fuels due partially to the low ionic conductivity of iron oxides. In order to address the low activity of iron-oxide-based oxygen carriers, support addition has been shown to lower the energy barrier of oxygen anion transport within the oxygen carrier. This work adds a mixed-ionic-and-electronic-conductor (MIEC) support to iron oxide to help facilitate O2- transport inside the lattice of iron oxide. The MIEC-supported iron oxide is compared to commonly used supports including TiO2 and Al2O 3 and the pure ionic conductor support yttria-stabilized zirconia (YSZ) for conversion of different carbonaceous fuels and hydrogen. Results show that the MIEC-supported iron oxide exhibits up to 70 times higher activity than non-MIEC-supported iron oxides for methane conversion. The MIEC supported iron oxide also shows good recyclability with only minor agglomeration and carbon formation observed. The effect of support-iron oxide synergies is further investigated to understand other physical and chemical properties that lead to highly active and recyclable oxygen carriers. Perovskite and fluorite-structured MIEC supports are tested for conversion of methane. The perovskite supported iron oxides exhibit higher activity and stability resulting from the high mixed conductivity of the support. Fluorite-structured CeO2 oxygen carriers deactivated by 75% after 10 redox cycles. This deactivation was attributed to agglomeration of iron oxide. The agglomeration was determined to occur due to Fe x+ transport during the oxidation step leading to high content of Fe on the surface of the oxygen carrier. Besides the MIEC supports, inert MgAl2O4 supported iron oxide is observed to activate in methane. The activation is attributed to carbon formation causing physical degradation of the oxygen carrier and leading to higher surface area and porosity. To achieve high activity with solid fuels, chemical looping with oxygen uncoupling (CLOU) is commonly used. This process uses oxygen carriers with high PO2 that allows the oxygen carrier to release a portion of their lattice oxygen as gaseous oxygen. In turn, the gaseous oxygen can react with solid fuel particles at a higher rate than the lattice oxygen. CaMnO 3 perovskite oxygen carriers offer high potential for CLOU. However, pure CaMnO3 suffers from long-term recyclability and sulfur poisoning. Addition of A-site (Ba and Sr) and B-site (Fe, Ni, Co, Al, and V) dopants are used to improve the performance of the base CaMnO3 oxygen carrier. Sr (A-site) and Fe (B-site) exhibit high compatibility with the base perovskite structure. Both dopants observe oxygen uncoupling properties up to 200°C below that of pure CaMnO3. Additionally, the doped structures also exhibit higher stability at high temperatures (>1000°C) and during redox cycles. The doped oxygen carriers also demonstrate significantly improved activity for coal char conversion.

Modulating conversion of isoflavone glycosides to aglycones using crude beta-glycosidase extracts from almonds and processed soy.

PubMed

Ahn-Jarvis, J H; Teegarden, M D; Schwartz, S J; Lee, K; Vodovotz, Y

2017-12-15

Food processing alters the physicochemical state of soy which can enhance chemical and enzymatic conversion of isoflavones to their aglycone forms. This study investigated the role of β-glycosidase from processed soy-ingredient mixture (SIM) or almonds, and examined the impact of isoflavone composition in mediating conversion to aglycones. β-Glycosidase activity was quantified using p-nitrophenol-β-d-glucopyranoside and SIM isoflavone extracts. Almond β-glycosidase activity was significantly (p<0.001) reduced after roasting (99% reduction) or steaming (97% reduction) compared to raw almonds. SIM β-glycosidase activity, however, increased, with steaming by 66% (p<0.001) and with roasting by 52% (p=0.022), compared to raw SIM. After incubation with β-glycosidase, percentage of aglycone (total aglycone/total isoflavones) in SIM isoflavone extracts increased significantly in raw (35%), fermented (48%), roasted (88%) and steamed (91%) SIM, compared to their initial (∼5%) compositions. Manipulation of β-glycosidase activity and isoflavone composition can be used to modulate aglycone content in soy food products. Copyright © 2017 Elsevier Ltd. All rights reserved.

Stratospheric aerosols and precursor gases

NASA Technical Reports Server (NTRS)

1982-01-01

Measurements were made of the aerosol size, height and geographical distribution, their composition and optical properties, and their temporal variation with season and following large volcanic eruptions. Sulfur-bearing gases were measured in situ in the stratosphere, and studied of the chemical and physical processes which control gas-to-particle conversion were carried out in the laboratory.

Mutation of Photosystem II D1 protein that empower efficient phenotypes of Chlamydomonas Reinhardtii under extreme environment in space

USDA-ARS?s Scientific Manuscript database

Oxygenic photosynthesis involves capture and conversion of light energy into chemical energy, a process fundamental to life including plant productivity on Earth. Photosynthetic electron transport is catalyzed by two photochemical reaction centres in series, photosystem II (PS II) and photosytem I (...

The Status of and key barriers in lignocellulosic ethanol production : a technological perspective

Treesearch

J.Y. Zhu; G.S. Wang; X.J. Pan; R. Gleisner

2008-01-01

The development of biorefineries to produce fuel ethanol and commodity chemicals from lignocellulosic biomass is a potential alternative to current reliance on non-renewable resources. However, many technological barriers remain despite research progress in the past several decades. This article examines the major process barriers in biochemical conversion of biomass...

Substrate-Related Factors Affecting Enzymatic Saccharification of Lignocelluloses: Our Recent Understanding

Treesearch

Shao-Yuan Leu; J.Y. Zhu

2013-01-01

Enzymatic saccharification of cellulose is a key step in conversion of plant biomass to advanced biofuel and chemicals. Many substrate-related factors affect saccharification. Rather than examining the role of each individual factor on overall saccharification efficiency, this study examined how each factor affects the three basic processes of a heterogeneous...

Process for conversion of levulinic acid to ketones

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dagle, Vanessa M.; Dagle, Robert A.

A method for generating desired platform chemicals from feedstocks such as cellulosic biomass feedstocks containing levulinic acid by decarboxylating a feed stock comprising levulinic acid to generate ketones. This is done by passing a feed stock comprising levulinic acid in a gas phase over a non-precious metal catalyst on a neutral support.

Effect of band-aligned double absorber layers on photovoltaic characteristics of chemical bath deposited PbS/CdS thin film solar cells.

PubMed

Ho Yeon, Deuk; Chandra Mohanty, Bhaskar; Lee, Seung Min; Soo Cho, Yong

2015-09-23

Here we report the highest energy conversion efficiency and good stability of PbS thin film-based depleted heterojunction solar cells, not involving PbS quantum dots. The PbS thin films were grown by the low cost chemical bath deposition (CBD) process at relatively low temperatures. Compared to the quantum dot solar cells which require critical and multistep complex procedures for surface passivation, the present approach, leveraging the facile modulation of the optoelectronic properties of the PbS films by the CBD process, offers a simpler route for optimization of PbS-based solar cells. Through an architectural modification, wherein two band-aligned junctions are stacked without any intervening layers, an enhancement of conversion efficiency by as much as 30% from 3.10 to 4.03% facilitated by absorption of a wider range of solar spectrum has been obtained. As an added advantage of the low band gap PbS stacked over a wide gap PbS, the devices show stability over a period of 10 days.

Phase restructuring in transition metal dichalcogenides for highly stable energy storage

DOE PAGES

Leng, Kai; Chen, Zhongxin; Zhao, Xiaoxu; ...

2016-09-16

Achieving homogeneous phase transition and uniform charge distribution is essential for good cycle stability and high capacity when phase conversion materials are used as electrodes. Herein, we show that chemical lithiation of bulk 2H-MoS 2 distorts its crystalline domains in three primary directions to produce mosaic-like 1T' nanocrystalline domains, which improve phase and charge uniformity during subsequent electrochemical phase conversion. 1T'-Li xMoS 2, a macroscopic dense material with interconnected nanoscale grains, shows excellent cycle stability and rate capability in a lithium rechargeable battery compared to bulk or exfoliated-restacked MoS 2. Transmission electron microscopy studies reveal that the interconnected MoS 2more » nanocrystals created during the phase change process are reformable even after multiple cycles of galvanostatic charging/discharging, which allows them to play important roles in the long term cycling performance of the chemically intercalated TMD materials. Finally, these studies shed light on how bulk TMDs can be processed into quasi-2D nanophase material for stable energy storage.« less

Ab initio calculations and kinetic modeling of thermal conversion of methyl chloride: implications for gasification of biomass.

PubMed

Singla, Mallika; Rasmussen, Morten Lund; Hashemi, Hamid; Wu, Hao; Glarborg, Peter; Pelucchi, Matteo; Faravelli, Tiziano; Marshall, Paul

2018-04-25

Limitations in current hot gas cleaning methods for chlorine species from biomass gasification may be a challenge for end use such as gas turbines, engines, and fuel cells, all requiring very low levels of chlorine. During devolatilization of biomass, chlorine is released partly as methyl chloride. In the present work, the thermal conversion of CH3Cl under gasification conditions was investigated. A detailed chemical kinetic model for pyrolysis and oxidation of methyl chloride was developed and validated against selected experimental data from the literature. Key reactions of CH2Cl with O2 and C2H4 for which data are scarce were studied by ab initio methods. The model was used to analyze the fate of methyl chloride in gasification processes. The results indicate that CH3Cl emissions will be negligible for most gasification technologies, but could be a concern for fluidized bed gasifiers, in particular in low-temperature gasification. The present work illustrates how ab initio theory and chemical kinetic modeling can help to resolve emission issues for thermal processes in industrial scale.

Solar to fuels conversion technologies: a perspective.

PubMed

Tuller, Harry L

2017-01-01

To meet increasing energy needs, while limiting greenhouse gas emissions over the coming decades, power capacity on a large scale will need to be provided from renewable sources, with solar expected to play a central role. While the focus to date has been on electricity generation via photovoltaic (PV) cells, electricity production currently accounts for only about one-third of total primary energy consumption. As a consequence, solar-to-fuel conversion will need to play an increasingly important role and, thereby, satisfy the need to replace high energy density fossil fuels with cleaner alternatives that remain easy to transport and store. The solar refinery concept (Herron et al. in Energy Environ Sci 8:126-157, 2015), in which captured solar radiation provides energy in the form of heat, electricity or photons, used to convert the basic chemical feedstocks CO 2 and H 2 O into fuels, is reviewed as are the key conversion processes based on (1) combined PV and electrolysis, (2) photoelectrochemically driven electrolysis and (3) thermochemical processes, all focused on initially converting H 2 O and CO 2 to H 2 and CO. Recent advances, as well as remaining challenges, associated with solar-to-fuel conversion are discussed, as is the need for an intensive research and development effort to bring such processes to scale.

Methanol from CO2 by organo-cocatalysis: CO2 capture and hydrogenation in one process step.

PubMed

Reller, Christian; Pöge, Matthias; Lißner, Andreas; Mertens, Florian O R L

2014-12-16

Carbon dioxide chemically bound to alcohol-amines was hydrogenated to methanol under retrieval of these industrially used CO2 capturing reagents. The energetics of the process can be seen as a partial cancellation of the exothermic heat of reaction of the hydrogenation with the endothermic one of the CO2 release from the capturing reagent. The process provides a means to significantly improve the energy efficiency of CO2 to methanol conversions.

Flow-through pretreatment of lignocellulosic biomass with inorganic nanoporous membranes

DOEpatents

Bhave, Ramesh R.; Lynd, Lee; Shao, Xiongjun

2018-04-03

A process for the pretreatment of lignocellulosic biomass is provided. The process generally includes flowing water through a pretreatment reactor containing a bed of particulate ligno-cellulosic biomass to produce a pressurized, high-temperature hydrolyzate exit stream, separating solubilized compounds from the hydrolyzate exit stream using an inorganic nanoporous membrane element, fractionating the retentate enriched in solubilized organic components and recycling the permeate to the pretreatment reactor. The pretreatment process provides solubilized organics in concentrated form for the subsequent conversion into biofuels and other chemicals.

Porous carbon-free SnSb anodes for high-performance Na-ion batteries

NASA Astrophysics Data System (ADS)

Choi, Jeong-Hee; Ha, Choong-Wan; Choi, Hae-Young; Seong, Jae-Wook; Park, Cheol-Min; Lee, Sang-Min

2018-05-01

A simple melt-spinning/chemical-etching process is developed to create porous carbon-free SnSb anodes. Sodium ion batteries (SIBs) incorporating these anodes exhibit excellent electrochemical performances by accomodating large volume changes during repeated cycling. The porous carbon-free SnSb anode produced by the melt-spinning/chemical-etching process shows a high reversible capacity of 481 mAh g-1, high ICE of 80%, stable cyclability with a high capacity retention of 99% after 100 cycles, and a fast rate capability of 327 mAh g-1 at 4C-rate. Ex-situ X-ray diffraction and high resolution-transmission electron microscopy analyses demonstrate that the synthesized porous carbon-free SnSb anodes involve the highly reversible reaction with sodium through the conversion and recombination reactions during sodiation/desodiation process. The novel and simple melt-spinning/chemical-etching synthetic process represents a technological breakthrough in the commercialization of Na alloy-able anodes for SIBs.

Chemical analysis of raw and processed Fructus arctii by high-performance liquid chromatography/diode array detection-electrospray ionization-mass spectrometry

PubMed Central

Qin, Kunming; Liu, Qidi; Cai, Hao; Cao, Gang; Lu, Tulin; Shen, Baojia; Shu, Yachun; Cai, Baochang

2014-01-01

Background: In traditional Chinese medicine (TCM), raw and processed herbs are used to treat the different diseases. Fructus Arctii, the dried fruits of Arctium lappa l. (Compositae), is widely used in the TCM. Stir-frying is the most common processing method, which might modify the chemical compositions in Fructus Arctii. Materials and Methods: To test this hypothesis, we focused on analysis and identification of the main chemical constituents in raw and processed Fructus Arctii (PFA) by high-performance liquid chromatography/diode array detection-electrospray ionization-mass spectrometry. Results: The results indicated that there was less arctiin in stir-fried materials than in raw materials. however, there were higher levels of arctigenin in stir-fried materials than in raw materials. Conclusion: We suggest that arctiin reduced significantly following the thermal conversion of arctiin to arctigenin. In conclusion, this finding may shed some light on understanding the differences in the therapeutic values of raw versus PFA in TCM. PMID:25422559

The Chemical Route to a Carbon Dioxide Neutral World.

PubMed

Martens, Johan A; Bogaerts, Annemie; De Kimpe, Norbert; Jacobs, Pierre A; Marin, Guy B; Rabaey, Korneel; Saeys, Mark; Verhelst, Sebastian

2017-03-22

Excessive CO 2 emissions in the atmosphere from anthropogenic activity can be divided into point sources and diffuse sources. The capture of CO 2 from flue gases of large industrial installations and its conversion into fuels and chemicals with fast catalytic processes seems technically possible. Some emerging technologies are already being demonstrated on an industrial scale. Others are still being tested on a laboratory or pilot scale. These emerging chemical technologies can be implemented in a time window ranging from 5 to 20 years. The massive amounts of energy needed for capturing processes and the conversion of CO 2 should come from low-carbon energy sources, such as tidal, geothermal, and nuclear energy, but also, mainly, from the sun. Synthetic methane gas that can be formed from CO 2 and hydrogen gas is an attractive renewable energy carrier with an existing distribution system. Methanol offers advantages as a liquid fuel and is also a building block for the chemical industry. CO 2 emissions from diffuse sources is a difficult problem to solve, particularly for CO 2 emissions from road, water, and air transport, but steady progress in the development of technology for capturing CO 2 from air is being made. It is impossible to ban carbon from the entire energy supply of mankind with the current technological knowledge, but a transition to a mixed carbon-hydrogen economy can reduce net CO 2 emissions and ultimately lead to a CO 2 -neutral world. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polychlorinated Biphenyls in a Temperate Alpine Glacier: 2. Model Results of Chemical Fate Processes.

PubMed

Steinlin, Christine; Bogdal, Christian; Pavlova, Pavlina A; Schwikowski, Margit; Lüthi, Martin P; Scheringer, Martin; Schmid, Peter; Hungerbühler, Konrad

2015-12-15

We present results from a chemical fate model quantifying incorporation of polychlorinated biphenyls (PCBs) into the Silvretta glacier, a temperate Alpine glacier located in Switzerland. Temperate glaciers, in contrast to cold glaciers, are glaciers where melt processes are prevalent. Incorporation of PCBs into cold glaciers has been quantified in previous studies. However, the fate of PCBs in temperate glaciers has never been investigated. In the model, we include melt processes, inducing elution of water-soluble substances and, conversely, enrichment of particles and particle-bound chemicals. The model is validated by comparing modeled and measured PCB concentrations in an ice core collected in the Silvretta accumulation area. We quantify PCB incorporation between 1900 and 2010, and discuss the fate of six PCB congeners. PCB concentrations in the ice core peak in the period of high PCB emissions, as well as in years with strong melt. While for lower-chlorinated PCB congeners revolatilization is important, for higher-chlorinated congeners, the main processes are storage in glacier ice and removal by particle runoff. This study gives insight into PCB fate and dynamics and reveals the effect of snow accumulation and melt processes on the fate of semivolatile organic chemicals in a temperate Alpine glacier.

Towards uncertainty estimates in global operational forecasts of trace gases in the Copernicus Atmosphere Monitoring System

NASA Astrophysics Data System (ADS)

Huijnen, V.; Bouarar, I.; Chabrillat, S. H.; Christophe, Y.; Thierno, D.; Karydis, V.; Marecal, V.; Pozzer, A.; Flemming, J.

2017-12-01

Operational atmospheric composition analyses and forecasts such as developed in the Copernicus Atmosphere Monitoring Service (CAMS) rely on modules describing emissions, chemical conversion, transport and removal processing, as well as data assimilation methods. The CAMS forecasts can be used to drive regional air quality models across the world. Critical analyses of uncertainties in any of these processes are continuously needed to advance the quality of such systems on a global scale, ranging from the surface up to the stratosphere. With regard to the atmospheric chemistry to describe the fate of trace gases, the operational system currently relies on a modified version of the CB05 chemistry scheme for the troposphere combined with the Cariolle scheme to describe stratospheric ozone, as integrated in ECMWF's Integrated Forecasting System (IFS). It is further constrained by assimilation of satellite observations of CO, O3 and NO2. As part of CAMS we have recently developed three fully independent schemes to describe the chemical conversion throughout the atmosphere. These parameterizations originate from parent model codes in MOZART, MOCAGE and a combination of TM5/BASCOE. In this contribution we evaluate the correspondence and elemental differences in the performance of the three schemes in an otherwise identical model configuration (excluding data-assimilation) against a large range of in-situ and satellite-based observations of ozone, CO, VOC's and chlorine-containing trace gases for both troposphere and stratosphere. This analysis aims to provide a measure of model uncertainty in the operational system for tracers that are not, or poorly, constrained by data assimilation. It aims also to provide guidance on the directions for further model improvement with regard to the chemical conversion module.

A safety analysis of food waste-derived animal feeds from three typical conversion techniques in China.

PubMed

Chen, Ting; Jin, Yiying; Shen, Dongsheng

2015-11-01

This study was based on the food waste to animal feed demonstration projects in China. A safety analysis of animal feeds from three typical treatment processes (i.e., fermentation, heat treatment, and coupled hydrothermal treatment and fermentation) was presented. The following factors are considered in this study: nutritive values characterized by organoleptic properties and general nutritional indices; the presence of bovine- and sheep-derived materials; microbiological indices for Salmonella, total coliform (TC), total aerobic plate counts (TAC), molds and yeast (MY), Staphylococcus Aureus (SA), and Listeria; chemical contaminant indices for hazardous trace elements such as Cr, Cd, and As; and nitrite and organic contaminants such as aflatoxin B1 (AFB1) and hexachlorocyclohexane (HCH). The present study reveals that the feeds from all three conversion processes showed balanced nutritional content and retained a certain feed value. The microbiological indices and the chemical contaminant indices for HCH, dichlorodiphenyltrichloroethane (DDT), nitrite, and mercury all met pertinent feed standards; however, the presence of bovine- and sheep-derived materials and a few chemical contaminants such as Pb were close to or might exceed the legislation permitted values in animal feeding. From the view of treatment techniques, all feed retained part of the nutritional values of the food waste after the conversion processes. Controlled heat treatment can guarantee the inactivation of bacterial pathogens, but none of the three techniques can guarantee the absence of cattle- and sheep-derived materials and acceptable levels of certain contaminants. The results obtained in this research and the feedstuffs legislation related to animal feed indicated that food waste-derived feed could be considered an adequate alternative to be used in animal diets, while the feeding action should be changed with the different qualities of the products, such as restrictions on the application of ruminants, and recycling as formula feeds. Copyright © 2015 Elsevier Ltd. All rights reserved.

Consolidated conversion of protein waste into biofuels and ammonia using Bacillus subtilis.

PubMed

Choi, Kwon-Young; Wernick, David G; Tat, Christine A; Liao, James C

2014-05-01

The non-recyclable use of nitrogen fertilizers in microbial production of fuels and chemicals remains environmentally detrimental. Conversion of protein wastes into biofuels and ammonia by engineering nitrogen flux in Escherichia coli has been demonstrated as a method to reclaim reduced-nitrogen and curb its environmental deposition. However, protein biomass requires a proteolysis process before it can be taken up and converted by any microbe. Here, we metabolically engineered Bacillus subtilis to hydrolyze polypeptides through its secreted proteases and to convert amino acids into advanced biofuels and ammonia fertilizer. Redirection of B. subtilis metabolism for amino-acid conversion required inactivation of the branched-chain amino-acid (BCAA) global regulator CodY. Additionally, the lipoamide acyltransferase (bkdB) was deleted to prevent conversion of branched-chain 2-keto acids into their acyl-CoA derivatives. With these deletions and heterologous expression of a keto-acid decarboxylase and an alcohol dehydrogenase, the final strain produced biofuels and ammonia from an amino-acid media with 18.9% and 46.6% of the maximum theoretical yield. The process was also demonstrated on several waste proteins. The results demonstrate the feasibility of direct microbial conversion of polypeptides into sustainable products. Copyright © 2014 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Efficient approach for bioethanol production from red seaweed Gelidium amansii.

PubMed

Kim, Ho Myeong; Wi, Seung Gon; Jung, Sera; Song, Younho; Bae, Hyeun-Jong

2015-01-01

Gelidium amansii (GA), a red seaweed species, is a popular source of food and chemicals due to its high galactose and glucose content. In this study, we investigated the potential of bioethanol production from autoclave-treated GA (ATGA). The proposed method involved autoclaving GA for 60min for hydrolysis to glucose. Separate hydrolysis and fermentation processing (SHF) achieved a maximum ethanol concentration of 3.33mg/mL, with a conversion yield of 74.7% after 6h (2% substrate loading, w/v). In contrast, simultaneous saccharification and fermentation (SSF) produced an ethanol concentration of 3.78mg/mL, with an ethanol conversion yield of 84.9% after 12h. We also recorded an ethanol concentration of 25.7mg/mL from SSF processing of 15% (w/v) dry matter from ATGA after 24h. These results indicate that autoclaving can improve the glucose and ethanol conversion yield of GA, and that SSF is superior to SHF for ethanol production. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comprehensive characterisation of sewage sludge for thermochemical conversion processes - Based on Singapore survey.

PubMed

Chan, Wei Ping; Wang, Jing-Yuan

2016-08-01

Recently, sludge attracted great interest as a potential feedstock in thermochemical conversion processes. However, compositions and thermal degradation behaviours of sludge were highly complex and distinctive compared to other traditional feedstock led to a need of fundamental research on sludge. Comprehensive characterisation of sludge specifically for thermochemical conversion was carried out for all existing Water Reclamation Plants in Singapore. In total, 14 sludge samples collected based on the type, plant, and batch categorisation. Existing characterisation methods for physical and chemical properties were analysed and reviewed using the collected samples. Qualitative similarities and quantitative variations of different sludge samples were identified and discussed. Oxidation of inorganic in sludge during ash forming analysis found to be causing significant deviations on proximate and ultimate analysis. Therefore, alternative parameters and comparison basis including Fixed Residues (FR), Inorganic Matters (IM) and Total Inorganics (TI) were proposed for better understanding on the thermochemical characteristics of sludge. Copyright © 2016 Elsevier Ltd. All rights reserved.

The conversion of lignocellulosics to fermentable sugars: A survey of current research and application to CELSS

NASA Technical Reports Server (NTRS)

Petersen, Gene R.; Baresi, Larry

1990-01-01

An overview of the options for converting lignocellulosics into fermentable sugars as applied to the Closed Ecological Life Support System (CELSS) is given. A requirement for pretreatment is shown as well as the many available options. At present, physical/chemical methods are the simplest and best characterized options, but enzymatic processes will likely be the method of choice in the future. The use of pentose sugars by microorganisms to produce edibles at levels comparable to conventional plants is shown. The possible use of mycelial food production on pretreated but not hydrolyzed lignocelluloscis is also presented. Simple tradeoff analysis among some of the many possible biological pathways to regeneration of waste lignocellulosics was undertaken. Comparisons with complete oxidation processes were made. It is suggested that the NASA Life Sciences CELSS program maintain relationships with other government agencies involved in lignocellulosic conversions and use their expertise when the actual need for such conversion technology arises rather than develop this expertise within NASA.

Integrated Biorefinery Project: Cooperative Research and Development Final Report, CRADA Number CRD-10-390

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chapeaux, A.; Schell, D.

2013-06-01

The Amyris-NREL CRADA is a sub-project of Amyris?s DOE-funded pilot-scale Integrated Biorefinery (IBR). The primary product of the Amyris IBR is Amyris Renewable Diesel. Secondary products will include lubricants, polymers and other petro-chemical substitutes. Amyris and its project partners will execute on a rapid project to integrate and leverage their collective expertise to enable the conversion of high-impact biomass feedstocks to these advanced, infrastructure-compatible products. The scope of the Amyris-NREL CRADA includes the laboratory development and pilot scale-up of bagasse pretreatment and enzymatic saccharification conditions by NREL for subsequent conversion of lignocellulosic sugar streams to Amyris Diesel and chemical productsmore » by Amyris. The CRADA scope also includes a techno-economic analysis of the overall production process of Amyris products from high-impact biomass feedstocks.« less

Structure and diffusion of furans and other cellulose-derived compounds in solvents via MD simulation

NASA Astrophysics Data System (ADS)

Rabideau, Brooks; Ismail, Ahmed

2011-03-01

There is now a large push towards the development of energy sources that are both environmentally friendly and sustainable; with the conversion of cellulose derived from biomass into biofuels being one promising route. In this conversion, a variety of intermediary compounds have been identified, which appear critical to successful expansion of the process to an industrial scale. Here we examine the structure and diffusion of these furans and acids derived from cellulose within ionic liquids via molecular dynamic simulation. Ionic liquids have shown the ability to dissolve cellulose with certain `green' benefits over existing, conventional solvents. Specifically, we study the solvation properties of these chemicals by examining the pair correlation functions of solute with solvent, and by exploring the agglomeration and separation of these chemicals from the solvent as well as the hydrogen bonding between species. Additionally, we determine the diffusion constant of these compounds in ionic liquid and aqueous solvents.

Optimization of air plasma reconversion of UF6 to UO2 based on thermodynamic calculations

NASA Astrophysics Data System (ADS)

Tundeshev, Nikolay; Karengin, Alexander; Shamanin, Igor

2018-03-01

The possibility of plasma-chemical conversion of depleted uranium-235 hexafluoride (DUHF) in air plasma in the form of gas-air mixtures with hydrogen is considered in the paper. Calculation of burning parameters of gas-air mixtures is carried out and the compositions of mixtures obtained via energy-efficient conversion of DUHF in air plasma are determined. With the help of plasma-chemical conversion, thermodynamic modeling optimal composition of UF6-H2-Air mixtures and its burning parameters, the modes for production of uranium dioxide in the condensed phase are determined. The results of the conducted researches can be used for creation of technology for plasma-chemical conversion of DUHF in the form of air-gas mixtures with hydrogen.

H{sub 2} Ortho-to-para Conversion on Grains: A Route to Fast Deuterium Fractionation in Dense Cloud Cores?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bovino, S.; Grassi, T.; Schleicher, D. R. G.

Deuterium fractionation, i.e., the enhancement of deuterated species with respect to non-deuterated ones, is considered to be a reliable chemical clock of star-forming regions. This process is strongly affected by the ortho-to-para H{sub 2} ratio. In this Letter we explore the effect of the ortho–para (o–p) H{sub 2} conversion on grains on the deuteration timescale in fully-depleted dense cores, including the most relevant uncertainties that affect this complex process. We show that (i) the o–p H{sub 2} conversion on grains is not strongly influenced by the uncertainties on the conversion time and the sticking coefficient, and (ii) that the processmore » is controlled by the temperature and the residence time of ortho-H{sub 2} on the surface, i.e., by the binding energy. We find that for binding energies between 330 and 550 K, depending on the temperature, the o–p H{sub 2} conversion on grains can shorten the deuterium fractionation timescale by orders of magnitude, opening a new route for explaining the large observed deuteration fraction D {sub frac} in dense molecular cloud cores. Our results suggest that the star formation timescale, when estimated through the timescale to reach the observed deuteration fractions, might be shorter than previously proposed. However, more accurate measurements of the binding energy are needed in order to better assess the overall role of this process.« less

The conversion of lignocellulosics to fermentable sugars - A survey of current research and applications to CELSS

NASA Technical Reports Server (NTRS)

Petersen, Gene R.; Baresi, Larry

1990-01-01

This report provides an overview options for converting lignocellulosics into fermentable sugars in CELSS. A requirement for pretreatment is shown. Physical-chemical and enzymatic hydrolysis processes for producing fermentable sugars are discussed. At present physical-chemical methods are the simplest and best characterized options, but enzymatic processes will be the likely method of choice in the future. The use of pentose sugars by microorganisms to produce edibles is possible. The use of mycelial food production on pretreated but not hydrolyzed lignocellulosics is also possible. Simple trade-off analyses to regenerate waste lignocellulosics for two pathways are made, one of which is compared to complete oxidation.

Nanostructured transition metal dichalcogenide electrocatalysts for CO2 reduction in ionic liquid.

PubMed

Asadi, Mohammad; Kim, Kibum; Liu, Cong; Addepalli, Aditya Venkata; Abbasi, Pedram; Yasaei, Poya; Phillips, Patrick; Behranginia, Amirhossein; Cerrato, José M; Haasch, Richard; Zapol, Peter; Kumar, Bijandra; Klie, Robert F; Abiade, Jeremiah; Curtiss, Larry A; Salehi-Khojin, Amin

2016-07-29

Conversion of carbon dioxide (CO2) into fuels is an attractive solution to many energy and environmental challenges. However, the chemical inertness of CO2 renders many electrochemical and photochemical conversion processes inefficient. We report a transition metal dichalcogenide nanoarchitecture for catalytic electrochemical CO2 conversion to carbon monoxide (CO) in an ionic liquid. We found that tungsten diselenide nanoflakes show a current density of 18.95 milliamperes per square centimeter, CO faradaic efficiency of 24%, and CO formation turnover frequency of 0.28 per second at a low overpotential of 54 millivolts. We also applied this catalyst in a light-harvesting artificial leaf platform that concurrently oxidized water in the absence of any external potential. Copyright © 2016, American Association for the Advancement of Science.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Mi; Pu, Yunqiao; Yoo, Chang Geun

The native recalcitrance of plants hinders the biomass conversion process using current biorefinery techniques. Down-regulation of the caffeic acid O-methyltransferase (COMT) gene in the lignin biosynthesis pathway of switchgrass reduced the thermochemical and biochemical conversion recalcitrance of biomass. Due to potential environmental influences on lignin biosynthesis and deposition, studying the consequences of physicochemical changes in field-grown plants without pretreatment is essential to evaluate the performance of lignin-altered plants. In this study, we determined the chemical composition, cellulose crystallinity and the degree of its polymerization, molecular weight of hemicellulose, and cellulose accessibility of cell walls in order to better understand themore » fundamental features of why biomass is recalcitrant to conversion without pretreatment. The most important is to investigate whether traits and features are stable in the dynamics of field environmental effects over multiple years.« less

Strategies for the Conversion of Lignin to High-Value Polymeric Materials: Review and Perspective.

PubMed

Upton, Brianna M; Kasko, Andrea M

2016-02-24

The majority of commodity plastics and materials are derived from petroleum-based chemicals, illustrating the strong dependence on products derived from non-renewable energy sources. As the most accessible, renewable form of carbon (in comparison to CO2), lignocellulosic biomass (defined as organic matter available on a renewable basis) has been acknowledged as the most logical carbon-based feedstock for a variety of materials such as biofuels and chemicals. This Review focuses on methods developed to synthesize polymers derived from lignin, monolignols, and lignin-derived chemicals. Major topics include the structure and processing of lignocellulosic biomass to lignin, polymers utilizing lignin as a macromonomer, synthesis of monomers and polymers from monolignols, and polymers from lignin-derived chemicals, such as vanillin.

Microwave-assisted liquefaction of rape straw for the production of bio-oils

Treesearch

Xing-Yan Huang; Feng Li; Jiu-Long Xie; Cornelis F. De Hoop; Chung-Yun Hse; Jin-Qiu Qi; Hui Xiao

2017-01-01

The acid-catalyzed liquefaction of rape straw in methanol using microwave energy was examined. Conversion yield and energy consumption were evaluated to profile the microwave-assisted liquefaction process. Chemical components of the bio-oils from various liquefaction conditions were identified. A higher reaction temperature was found to be beneficial to obtain higher...

Gasification: A Cornerstone Technology

ScienceCinema

Gary Stiegel

2017-12-09

NETL is a leader in the science and technology of gasification - a process for the conversion of carbon-based materials such as coal into synthesis gas (syngas) that can be used to produce clean electrical energy, transportation fuels, and chemicals efficiently and cost-effectively using domestic fuel resources. Gasification is a cornerstone technology of 21st century zero emissions powerplants

Hydroxy acetone and lactic acid synthesis from aqueous propylene glycol/hydrogen peroxide catalysis on Pd-black

DOE Office of Scientific and Technical Information (OSTI.GOV)

Disselkamp, Robert S.; Harris, Benjamin D.; Hart, Todd R.

2008-07-20

The production of polyol chemicals is of increasing interest as they are obtained from the catalytic processing of biological feedstock materials, which also is becoming more prevalent. A case in point is glycerol production, formed as a byproduct in biodiesel catalytic processing. Here we report the reaction of a simple 1,2-diol, propylene glycol, with hydrogen peroxide and a Pd-black catalyst under reflux conditions at 368 K. The experiments were performed by either co-addition of hydrogen peroxide with air sparging, or addition of hydrogen peroxide alone, each yielding hydroxy acetone (HA) and acetic acid (AA) products, with a lesser amount ofmore » lactic acid (LA) formed. Product conversion data at near neutral pH versus hydrogen peroxide equivalents added relative to substrate is presented. Hydrogen peroxide addition without air sparging at 5 equivalents resulted in 65% conversion with an HA:AA molar ratio of 2:1. Conversely, hydrogen peroxide addition with air sparging at only 0.75 equivalents resulted in 40% conversion with an HA:AA ratio of 3:1. From this it is concluded that although the product distribution in these chemistries is somewhat unchanged by air sparging, it is surprising that the amount of reactive oxygen is greatly enhanced with co-addition of O2/H2O2. Additional studies have revealed the amount of LA formed can be enhanced under acidic conditions (pH=1.5 compared to pH=8.5), such that 26% of total product formation is LA. Since hydrogen peroxide is an environmentally clean reagent and becoming more cost effective to use, this work may guide future applied investigations into polyol chemical syntheses.« less

NREL's Cyanobacteria Engineering Shortens Biofuel Production Process, Captures CO2

DOE Office of Scientific and Technical Information (OSTI.GOV)

2015-09-01

This highlight describes NREL's work to systematically analyze the flow of energy in a photosynthetic microbe and show how the organism adjusts its metabolism to meet the increased energy demand for making ethylene. This work successfully demonstrates that the organism could cooperate by stimulating photosynthesis. The results encourage further genetic engineering for the conversion of CO2 to biofuels and chemicals. This highlight is being developed for the September 2015 Alliance S&T Board meeting. biofuels and chemicals. This highlight is being developed for the September 2015 Alliance S&T Board meeting.

Tropospheric Chemistry

NASA Technical Reports Server (NTRS)

Mohnen, V.

1984-01-01

The fundamental processes that control the chemical composition and cycles of the global troposphere and how these processes and properties affect the physical behavior of the atmosphere are examined. The long-term information needs for tropospheric chemistry are: to be able to predict tropospheric responses to perturbations, both natural and anthropogenic, of these cycles, and to provide the information required for the maintenance and effective future management of the atmospheric component of our global life support system. The processes controlling global tropospheric biogeochemical cycles include: the input of trace species into the troposphere, their long-range transport and distribution as affected by the mean wind and vertical venting, their chemical transformations, including gas to particle conversion, leading to the appearance of aerosols or aqueous phase reactions inside cloud droplets, and their removal from the troposphere via wet (precipitation) and dry deposition.

Catalytic Upgrading of Thermochemical Intermediates to Hydrocarbons: Conversion of Lignocellulosic Feedstocks to Aromatic Fuels and High Value Chemicals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cortright, Randy; Rozmiarek, Bob; Van Straten, Matt

The principal objective of this project was to develop a fully integrated catalytic process that efficiently converts lignocellulosic feedstocks (e.g. bagasse, corn stover, and loblolly pine) into aromatic-rich fuels and chemicals. Virent led this effort with key feedstock support from Iowa State University. Within this project, Virent leveraged knowledge of catalytic processing of sugars and biomass to investigate two liquefaction technologies (Reductive Catalytic Liquefaction (USA Patent No. 9,212,320, 2015) and Solvolysis (USA Patent No. 9,157,030, 2015) (USA Patent No. 9,157,031, 2015)) that take advantage of proprietary catalysts at temperatures less than 300°C in the presence of unique solvent molecules generatedmore » in-situ within the liquefaction processes.« less

A Study of Energy Conversion Devices Using Photoactive Organometallic Electrocatalysts.

DTIC Science & Technology

1986-05-23

arylisocyanide complexes confined to polymeric thin films in solar energy conversion systems . The chemical systems of interest were chromium...The goals of the project then became threefold: 1) examine the thermo- dynamics an- ’ kinetics of charge transfer in the systems in which we had shown...complexes confined to polymeric thin films in solar energy conversion systems . The chemical systems of interest were chromium, molybdenum and

Intermediate Temperature Hybrid Fuel Cell System for the Conversion of Natural to Electricity and Liquid Fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krause, Theodore

This goal of this project was to develop a new hybrid fuel cell technology that operates directly on natural gas or biogas to generate electrical energy and to produce ethane or ethylene from methane, the main component of natural gas or biogas, which can be converted to a liquid fuel or high-value chemical using existing process technologies. By taking advantage of the modularity and scalability of fuel cell technology, this combined fuel cell/chemical process technology targets the recovery of stranded natural gas available at the well pad or biogas produced at waste water treatment plants and municipal landfills by convertingmore » it to a liquid fuel or chemical. By converting the stranded gas to a liquid fuel or chemical, it can be cost-effectively transported to market thus allowing the stranded natural gas or biogas to be monetized instead of flared, producing CO2, a greenhouse gas, because the volumes produced at these locations are too small to be economically recovered using current gas-to-liquids process technologies.« less

One-Step Reforming of CO2 and CH4 into High-Value Liquid Chemicals and Fuels at Room Temperature by Plasma-Driven Catalysis.

PubMed

Wang, Li; Yi, Yanhui; Wu, Chunfei; Guo, Hongchen; Tu, Xin

2017-10-23

The conversion of CO 2 with CH 4 into liquid fuels and chemicals in a single-step catalytic process that bypasses the production of syngas remains a challenge. In this study, liquid fuels and chemicals (e.g., acetic acid, methanol, ethanol, and formaldehyde) were synthesized in a one-step process from CO 2 and CH 4 at room temperature (30 °C) and atmospheric pressure for the first time by using a novel plasma reactor with a water electrode. The total selectivity to oxygenates was approximately 50-60 %, with acetic acid being the major component at 40.2 % selectivity, the highest value reported for acetic acid thus far. Interestingly, the direct plasma synthesis of acetic acid from CH 4 and CO 2 is an ideal reaction with 100 % atom economy, but it is almost impossible by thermal catalysis owing to the significant thermodynamic barrier. The combination of plasma and catalyst in this process shows great potential for manipulating the distribution of liquid chemical products in a given process. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Efficient electrochemical CO2 conversion powered by renewable energy.

PubMed

Kauffman, Douglas R; Thakkar, Jay; Siva, Rajan; Matranga, Christopher; Ohodnicki, Paul R; Zeng, Chenjie; Jin, Rongchao

2015-07-22

The catalytic conversion of CO2 into industrially relevant chemicals is one strategy for mitigating greenhouse gas emissions. Along these lines, electrochemical CO2 conversion technologies are attractive because they can operate with high reaction rates at ambient conditions. However, electrochemical systems require electricity, and CO2 conversion processes must integrate with carbon-free, renewable-energy sources to be viable on larger scales. We utilize Au25 nanoclusters as renewably powered CO2 conversion electrocatalysts with CO2 → CO reaction rates between 400 and 800 L of CO2 per gram of catalytic metal per hour and product selectivities between 80 and 95%. These performance metrics correspond to conversion rates approaching 0.8-1.6 kg of CO2 per gram of catalytic metal per hour. We also present data showing CO2 conversion rates and product selectivity strongly depend on catalyst loading. Optimized systems demonstrate stable operation and reaction turnover numbers (TONs) approaching 6 × 10(6) molCO2 molcatalyst(-1) during a multiday (36 h total hours) CO2 electrolysis experiment containing multiple start/stop cycles. TONs between 1 × 10(6) and 4 × 10(6) molCO2 molcatalyst(-1) were obtained when our system was powered by consumer-grade renewable-energy sources. Daytime photovoltaic-powered CO2 conversion was demonstrated for 12 h and we mimicked low-light or nighttime operation for 24 h with a solar-rechargeable battery. This proof-of-principle study provides some of the initial performance data necessary for assessing the scalability and technical viability of electrochemical CO2 conversion technologies. Specifically, we show the following: (1) all electrochemical CO2 conversion systems will produce a net increase in CO2 emissions if they do not integrate with renewable-energy sources, (2) catalyst loading vs activity trends can be used to tune process rates and product distributions, and (3) state-of-the-art renewable-energy technologies are sufficient to power larger-scale, tonne per day CO2 conversion systems.

An environmentally compliant cerium-based conversion coating for aluminum protection

NASA Astrophysics Data System (ADS)

Lin, Xuan

Chromate conversion coatings have been extensively used in the aircraft industry for the corrosion protection of aluminum alloys. Unfortunately, hexavalent chromium, which is a primary component in the chromating process, is a confirmed carcinogen. Because of rising remediation and disposal costs caused by increasingly strict regulations, the replacement of the traditional chromate conversion process is becoming a top priority in the metal finishing industry. This research focused on the electrodeposition of cerium-based coatings on 7075-T6 aluminum alloy in an electrolyte containing a cerium salt, an oxidizing agent and an organic solvent. The cerium-rich deposits were characterized by phase composition, oxidation state, coating thickness, surface morphology, deposition mechanism and polarization behavior. Chemical and electrochemical tests were utilized to compare the corrosion resistance between cerium-based coatings and chromate conversion coatings. To characterize and simulate the deposition process, a variety of approaches were utilized to study the oxidation states of cerium in various soluble and precipitated forms as a function of hydrogen peroxide and electrolyte pH. The pH ranges where the oxidation and reduction reactions dominate were determined. Further studies were performed to optimize the corrosion performance of cerium-based coatings and to understand the effects of electrolyte constituents and deposition parameters. The optimum levels for these variables were identified. A patent disclosure on the cerium-based coating process was made to the University of Missouri-Rolla and has now been officially filed with the U.S. Patent Office.

Conversion and assimilation of furfural and 5-(hydroxymethyl)furfural by Pseudomonas putida KT2440

DOE PAGES

Guarnieri, Michael T.; Franden, Mary Ann; Johnson, Christopher W.; ...

2017-02-08

The sugar dehydration products, furfural and 5-(hydroxymethyl)furfural (HMF), are commonly formed during high-temperature processing of lignocellulose, most often in thermochemical pretreatment, liquefaction, or pyrolysis. Typically, these two aldehydes are considered major inhibitors in microbial conversion processes. Many microbes can convert these compounds to their less toxic, dead-end alcohol counterparts, furfuryl alcohol and 5-(hydroxymethyl)furfuryl alcohol. Recently, the genes responsible for aerobic catabolism of furfural and HMF were discovered in Cupriavidus basilensis HMF14 to enable complete conversion of these compounds to the TCA cycle intermediate, 2-oxo-glutarate. In this work, we engineer the robust soil microbe, Pseudomonas putida KT2440, to utilize furfural andmore » HMF as sole carbon and energy sources via complete genomic integration of the 12 kB hmf gene cluster previously reported from Burkholderia phytofirmans. The common intermediate, 2-furoic acid, is shown to be a bottleneck for both furfural and HMF metabolism. When cultured on biomass hydrolysate containing representative amounts of furfural and HMF from dilute-acid pretreatment, the engineered strain outperforms the wild type microbe in terms of reduced lag time and enhanced growth rates due to catabolism of furfural and HMF. Overall, this study demonstrates that an approach for biological conversion of furfural and HMF, relative to the typical production of dead-end alcohols, enables both enhanced carbon conversion and substantially improves tolerance to hydrolysate inhibitors. Furthermore, this approach should find general utility both in emerging aerobic processes for the production of fuels and chemicals from biomass-derived sugars and in the biological conversion of high-temperature biomass streams from liquefaction or pyrolysis where furfural and HMF are much more abundant than in biomass hydrolysates from pretreatment.« less

Conversion and assimilation of furfural and 5-(hydroxymethyl)furfural by Pseudomonas putida KT2440

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guarnieri, Michael T.; Franden, Mary Ann; Johnson, Christopher W.

The sugar dehydration products, furfural and 5-(hydroxymethyl)furfural (HMF), are commonly formed during high-temperature processing of lignocellulose, most often in thermochemical pretreatment, liquefaction, or pyrolysis. Typically, these two aldehydes are considered major inhibitors in microbial conversion processes. Many microbes can convert these compounds to their less toxic, dead-end alcohol counterparts, furfuryl alcohol and 5-(hydroxymethyl)furfuryl alcohol. Recently, the genes responsible for aerobic catabolism of furfural and HMF were discovered in Cupriavidus basilensis HMF14 to enable complete conversion of these compounds to the TCA cycle intermediate, 2-oxo-glutarate. In this work, we engineer the robust soil microbe, Pseudomonas putida KT2440, to utilize furfural andmore » HMF as sole carbon and energy sources via complete genomic integration of the 12 kB hmf gene cluster previously reported from Burkholderia phytofirmans. The common intermediate, 2-furoic acid, is shown to be a bottleneck for both furfural and HMF metabolism. When cultured on biomass hydrolysate containing representative amounts of furfural and HMF from dilute-acid pretreatment, the engineered strain outperforms the wild type microbe in terms of reduced lag time and enhanced growth rates due to catabolism of furfural and HMF. Overall, this study demonstrates that an approach for biological conversion of furfural and HMF, relative to the typical production of dead-end alcohols, enables both enhanced carbon conversion and substantially improves tolerance to hydrolysate inhibitors. Furthermore, this approach should find general utility both in emerging aerobic processes for the production of fuels and chemicals from biomass-derived sugars and in the biological conversion of high-temperature biomass streams from liquefaction or pyrolysis where furfural and HMF are much more abundant than in biomass hydrolysates from pretreatment.« less

Conversion and assimilation of furfural and 5-(hydroxymethyl)furfural by Pseudomonas putida KT2440.

PubMed

Guarnieri, Michael T; Ann Franden, Mary; Johnson, Christopher W; Beckham, Gregg T

2017-06-01

The sugar dehydration products, furfural and 5-(hydroxymethyl)furfural (HMF), are commonly formed during high-temperature processing of lignocellulose, most often in thermochemical pretreatment, liquefaction, or pyrolysis. Typically, these two aldehydes are considered major inhibitors in microbial conversion processes. Many microbes can convert these compounds to their less toxic, dead-end alcohol counterparts, furfuryl alcohol and 5-(hydroxymethyl)furfuryl alcohol. Recently, the genes responsible for aerobic catabolism of furfural and HMF were discovered in Cupriavidus basilensis HMF14 to enable complete conversion of these compounds to the TCA cycle intermediate, 2-oxo-glutarate. In this work, we engineer the robust soil microbe, Pseudomonas putida KT2440, to utilize furfural and HMF as sole carbon and energy sources via complete genomic integration of the 12 kB hmf gene cluster previously reported from Burkholderia phytofirmans . The common intermediate, 2-furoic acid, is shown to be a bottleneck for both furfural and HMF metabolism. When cultured on biomass hydrolysate containing representative amounts of furfural and HMF from dilute-acid pretreatment, the engineered strain outperforms the wild type microbe in terms of reduced lag time and enhanced growth rates due to catabolism of furfural and HMF. Overall, this study demonstrates that an approach for biological conversion of furfural and HMF, relative to the typical production of dead-end alcohols, enables both enhanced carbon conversion and substantially improves tolerance to hydrolysate inhibitors. This approach should find general utility both in emerging aerobic processes for the production of fuels and chemicals from biomass-derived sugars and in the biological conversion of high-temperature biomass streams from liquefaction or pyrolysis where furfural and HMF are much more abundant than in biomass hydrolysates from pretreatment.

Mineralogical conversion of asbestos containing materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pulsford, S.K.; Foltz, A.D.; Ek, R.B.

The principal objective of the Technical Task Plan (TTP) is to demonstrate a thermal-chemical mineralogical asbestos conversion unit at the Hanford Site, which converts non-radiological asbestos containing materials (ACMs) into an asbestos-free material. The permanent thermal-chemical mineralogical conversion of ACMs to a non-toxic, non-hazardous, potentially marketable end product should not only significantly reduce the waste stream volumes but terminate the {open_quotes}cradle to grave{close_quotes} ownership liabilities.

Procedure for contact electrical resistance measurements as developed for use at Sandia National Laboratories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Finch, J.L.

1994-06-01

Military Specifications call out general procedures and guidelines for conducting contact resistance measurements on chemical conversion coated panels. This paper deals with a test procedure developed at Sandia National Laboratories used to conduct contact electrical resistance on non-chromated conversion coated test panels. MIL-C-81706 {open_quotes}Chemical Conversion Materials For Coating Aluminum and Aluminum Alloys{close_quotes} was the reference specification used for guidance.

Conversion of Lignocellulosic Biomass to Nanocellulose: Structure and Chemical Process

PubMed Central

Lee, H. V.; Hamid, S. B. A.; Zain, S. K.

2014-01-01

Lignocellulosic biomass is a complex biopolymer that is primary composed of cellulose, hemicellulose, and lignin. The presence of cellulose in biomass is able to depolymerise into nanodimension biomaterial, with exceptional mechanical properties for biocomposites, pharmaceutical carriers, and electronic substrate's application. However, the entangled biomass ultrastructure consists of inherent properties, such as strong lignin layers, low cellulose accessibility to chemicals, and high cellulose crystallinity, which inhibit the digestibility of the biomass for cellulose extraction. This situation offers both challenges and promises for the biomass biorefinery development to utilize the cellulose from lignocellulosic biomass. Thus, multistep biorefinery processes are necessary to ensure the deconstruction of noncellulosic content in lignocellulosic biomass, while maintaining cellulose product for further hydrolysis into nanocellulose material. In this review, we discuss the molecular structure basis for biomass recalcitrance, reengineering process of lignocellulosic biomass into nanocellulose via chemical, and novel catalytic approaches. Furthermore, review on catalyst design to overcome key barriers regarding the natural resistance of biomass will be presented herein. PMID:25247208

Conversion of stranded waste-stream carbon and nutrients into value-added products via metabolically coupled binary heterotroph-photoautotroph system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bohutskyi, Pavlo; Kucek, Leo A.; Hill, Eric

Metabolic flexibility and robustness of phototroph- heterotroph co-cultures provide a flexible binary engineering platform for a variety of biotechnological and environmental applications. Here, we metabolically coupled a heterotrophic bacterium Bacillus subtilis with astaxanthin producing alga Haematococcus pluvialis and successfully applied this binary co-culture for conversion of the starch-rich waste stream into valuable astaxanthin-rich biomass. Importantly, the implemented system required less mass transfer of CO2 and O2 due to in-situ exchange between heterotroph and phototroph, which can contribute to reduction in energy consumption for wastewater treatment. In addition, the maximum reduction in chemical oxygen demand, total nitrogen and phosphorus reached 65%,more » 55% and 30%, respectively. The preliminary economic analysis indicated that realization of produced biomass with 0.8% astaxanthin content may generate annual revenues of $3.2M (baseline scenario) from treatment of wastewater (1,090 m3/day) from a potato processing plant. Moreover, the revenues may be increased up to $18.2M for optimized scenario with astaxanthin content in algae of 2%. This work demonstrates a successful proof-of-principle for conversion of waste carbon and nutrients into targeted value-added products through metabolic connection of heterotrophic and phototrophic organisms. Utilization of heterotrophic-algal binary cultures opens new perspectives for designing highly-efficient production processes for feedstock biomass production as well as allows utilization of variety of organic agricultural, chemical, or municipal wastes.« less

In-Situ Generated Graphene as the Catalytic Site for Visible-Light Mediated Ethylene Epoxidation on AG Nanocatalysts

NASA Astrophysics Data System (ADS)

Zhang, Xueqiang Alex; Jain, Prashant

2017-06-01

Despite the harsh conditions for chemical conversion, ethylene oxide produced from ethylene epoxidation on Ag-based heterogeneous catalyst constitutes one of the largest volume chemicals in chemical industry. Recently, photocatalytic epoxidation of ethylene over plasmonic Ag nanoparticles enables the chemical conversion under significantly decreased temperature and ambient pressure conditions. Yet a detailed understanding of the photocatalytic process at the reactant/catalyst interface is under debate. Surface enhanced Raman spectroscopy (SERS) is a powerful vibrational spectroscopy technique that enables the localized detection of rare and/or transient chemical species with high sensitivity under in situ and ambient conditions. Using SERS, we are able to monitor at individual sites of an Ag nanocatalyst the visible-light-mediated adsorption and epoxidation of ethylene. From detected intermediates, we find that the primary step in the photoepoxidation is the transient formation of graphene catalyzed by the Ag surface. Density functional theory (DFT) simulations that model the observed SERS spectra suggest that the defective edge sites of the graphene formed on Ag constitute the active site for C2H4 adsorption and epoxidation. Further studies with pre-formed graphene/Ag catalyst composites confirm the indispensable role of graphene in visible-light-mediated ethylene epoxidation. Carbon is often thought to be either an innocent support or a poison for metallic catalysts; however our studies reveal a surprising role for crystalline carbon layers as potential co-catalysts.

Vitamin B1-catalyzed acetoin formation from acetaldehyde: a key step for upgrading bioethanol to bulk C₄ chemicals.

PubMed

Lu, Ting; Li, Xiukai; Gu, Liuqun; Zhang, Yugen

2014-09-01

The production of bulk chemicals and fuels from renewable biobased feedstocks is of significant importance for the sustainability of human society. The production of ethanol from biomass has dramatically increased and bioethanol also holds considerable potential as a versatile building block for the chemical industry. Herein, we report a highly selective process for the conversion of ethanol to C4 bulk chemicals, such as 2,3-butanediol and butene, via a vitamin B1 (thiamine)-derived N-heterocyclic carbene (NHC)-catalyzed acetoin condensation as the key step to assemble two C2 acetaldehydes into a C4 product. The environmentally benign and cheap natural catalyst vitamin B1 demonstrates high selectivity (99%), high efficiency (97% yield), and high tolerance toward ethanol and water impurities in the acetoin reaction. The results enable a novel and efficient process for ethanol upgrading. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nabeel, A.; Khan, M.A.; Husain, S.

Coal is the most abundant source of energy. However, there is a need to develop cleaner, and more efficient, economical, and convenient coal conversion technologies. It is important to understand the organic chemical structure of coal for achieving real breakthroughs in the development of such coal conversion technologies. A novel computer-assisted modeling technique based on the analysis of {sup 13}C NMR and gel permeation chromatography has been applied to predict the average molecular structure of the acetylated product of a depolymerized bituminous Indian coal. The proposed molecular structure may be of practical use in understanding the mechanism of coal conversionsmore » during the processes of liquefaction, gasification, combustion, and carbonization.« less

Nonlinear electromagnetic interactions in energetic materials

DOE PAGES

Wood, Mitchell Anthony; Dalvit, Diego Alejandro; Moore, David Steven

2016-01-12

We study the scattering of electromagnetic waves in anisotropic energetic materials. Nonlinear light-matter interactions in molecular crystals result in frequency-conversion and polarization changes. Applied electromagnetic fields of moderate intensity can induce these nonlinear effects without triggering chemical decomposition, offering a mechanism for the nonionizing identification of explosives. We use molecular-dynamics simulations to compute such two-dimensional THz spectra for planar slabs made of pentaerythritol tetranitrate and ammonium nitrate. Finally, we discuss third-harmonic generation and polarization-conversion processes in such materials. These observed far-field spectral features of the reflected or transmitted light may serve as an alternative tool for standoff explosive detection.

Bio-oil from fast pyrolysis of lignin: Effects of process and upgrading parameters.

PubMed

Fan, Liangliang; Zhang, Yaning; Liu, Shiyu; Zhou, Nan; Chen, Paul; Cheng, Yanling; Addy, Min; Lu, Qian; Omar, Muhammad Mubashar; Liu, Yuhuan; Wang, Yunpu; Dai, Leilei; Anderson, Erik; Peng, Peng; Lei, Hanwu; Ruan, Roger

2017-10-01

Effects of process parameters on the yield and chemical profile of bio-oil from fast pyrolysis of lignin and the processes for lignin-derived bio-oil upgrading were reviewed. Various process parameters including pyrolysis temperature, reactor types, lignin characteristics, residence time, and feeding rate were discussed and the optimal parameter conditions for improved bio-oil yield and quality were concluded. In terms of lignin-derived bio-oil upgrading, three routes including pretreatment of lignin, catalytic upgrading, and co-pyrolysis of hydrogen-rich materials have been investigated. Zeolite cracking and hydrodeoxygenation (HDO) treatment are two main methods for catalytic upgrading of lignin-derived bio-oil. Factors affecting zeolite activity and the main zeolite catalytic mechanisms for lignin conversion were analyzed. Noble metal-based catalysts and metal sulfide catalysts are normally used as the HDO catalysts and the conversion mechanisms associated with a series of reactions have been proposed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Romania program targets methanol and Fischer-Tropsch research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1987-03-01

Currently, the chemical organic industry, the petrochemical and engine fuels industry in Romania are entirely based on hydrocarbons from oil. To reduce the oil dependence of this sector and to ensure the stipulated growth rate of 8-9%, research and development programs have been set up with a view to the diversification of raw materials. In research on hydrocarbons from alcohol conversion, three process variants are known, i.e. olefins from methanol, gasolines from methanol and a combined gasolines and aromatic hydrocarbons from methanol. The Romanian process of methanol conversion to hydrocarbons is very flexible, with all the variants mentioned being carriedmore » out in the same plant by modifying the catalysts. In research on hydrocarbons from synthesis gas a modern process is being developed for gasification of brown coal in a fluidized bed, under pressure, in the presence of oxygen and water vapors. In the field of carbon oxide hydrogenation, studies have been carried out on selective Fischer-Tropsch processes in which the reaction products are high value hydrocarbon fractions.« less

Non-aqueous homogenous biocatalytic conversion of polysaccharides in ionic liquids using chemically modified glucosidase.

PubMed

Brogan, Alex P S; Bui-Le, Liem; Hallett, Jason P

2018-06-25

The increasing requirement to produce platform chemicals and fuels from renewable sources means advances in biocatalysis are rapidly becoming a necessity. Biomass is widely used in nature as a source of energy and as chemical building blocks. However, recalcitrance towards traditional chemical processes and solvents provides a significant barrier to widespread utility. Here, by optimizing enzyme solubility in ionic liquids, we have discovered solvent-induced substrate promiscuity of glucosidase, demonstrating an unprecedented example of homogeneous enzyme bioprocessing of cellulose. Specifically, chemical modification of glucosidase for solubilization in ionic liquids can increase thermal stability to up to 137 °C, allowing for enzymatic activity 30 times greater than is possible in aqueous media. These results establish that through a synergistic combination of chemical biology (enzyme modification) and reaction engineering (solvent choice), the biocatalytic capability of enzymes can be intensified: a key step towards the full-scale deployment of industrial biocatalysis.

Utilization of coal as a source of chemicals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demirbas, A.

Coal consists carbon-based substances can be used as a source of specialty aromatic chemicals and aliphatic chemicals. Four widespread processes allow for making chemicals from coals: gasification, liquefaction, direct conversion, and co-production of chemicals and fuels along with electricity. Coal is gasified to produce synthesis gas (syngas) with a gasifier which is then converted to paraffinic liquid fuels and chemicals by Fischer-Tropsch synthesis. Liquid product from coal gasification mainly contains benzene, toluene, xylene (BTX), phenols, alkylphenols, and cresol. Methanol is made using coal or syngas with hydrogen and carbon monoxide in a 2 to 1 ratio. Coal-derived methanol has manymore » preferable properties as it is free of sulfur and other impurities. Syngas from coal can be reformed to hydrogen. Ammonium sulfate from coal tar by pyrolysis can be converted to ammonia. The humus substances can be recovered from brown coal by alkali extraction.« less

Comparing Ultrasound and Mechanical Steering in a Biodiesel Production Process

NASA Astrophysics Data System (ADS)

Costa-Felix, Rodrigo P. B.; Ferreira, Jerusa R. L.

The analysis of the kinetics of the transesterification reaction is crucial to compare different routes or routes with different catalysts or reaction accelerators. The use of ultrasound is considereda method for accelerating the biodiesel production. However, little effort has been done and is reported in the literature about how and under what conditions the use of ultrasound really speeds up the process, or the conditions under which its use is unnecessary or even harmful, burdening the process. Two dissimilar energy injections into a typical route were tested: ultrasound (@ 1 MHz and no heating) and mechanical steering (with heating), both applied in an 8:1 ratio of soybean oil and methanol, adding 1% of KOH as catalyzer. As results, during the first 10 minutes of reaction ultrasound showed unbearable effect on the transesterification, whilst mechanical steering and heating achieved almost 70% of conversion ratio. However, during the following 10 minutes, the mechanical steering and heating got nothing more than 80% of conversion, a considerable less efficient process than ultrasound assisted one, which achieved more than 90%. The straightforward explanation is that ultrasound continually inserts energy in a slower rate, what can result in a more stable conversion scenario. On the other hand, mechanical steering and heating provides more energy at a glance, but cannot push the final conversion rate beyond a limit, as the transesterification is a double-way chemical process. The instability mechanical steering and heating settles in the reaction medium pulls the components back to their original states more than pushes than to the converted equilibrium state of the matter.

Light-energy conversion in engineered microorganisms.

PubMed

Johnson, Ethan T; Schmidt-Dannert, Claudia

2008-12-01

Increasing interest in renewable resources by the energy and chemical industries has spurred new technologies both to capture solar energy and to develop biologically derived chemical feedstocks and fuels. Advances in molecular biology and metabolic engineering have provided new insights and techniques for increasing biomass and biohydrogen production, and recent efforts in synthetic biology have demonstrated that complex regulatory and metabolic networks can be designed and engineered in microorganisms. Here, we explore how light-driven processes may be incorporated into nonphotosynthetic microbes to boost metabolic capacity for the production of industrial and fine chemicals. Progress towards the introduction of light-driven proton pumping or anoxygenic photosynthesis into Escherichia coli to increase the efficiency of metabolically-engineered biosynthetic pathways is highlighted.

[The concept of the development of the state of chemical-analytical environmental monitoring].

PubMed

Rakhmanin, Iu A; Malysheva, A G

2013-01-01

Chemical and analytical monitoring of the quality of environment is based on the accounting of the trace amount of substances. Considering the multicomponent composition of the environment and running processes of transformation of substances in it, in determination of the danger of the exposure to the chemical pollution of environment on population health there is necessary evaluation based on the simultaneous account of complex of substances really contained in the environment and supplying from different sources. Therefore, in the analytical monitoring of the quality and safety of the environment there is a necessary conversion from the orientation, based on the investigation of specific target substances, to estimation of real complex of compounds.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Dongwook; Vardon, Derek R.; Murali, Dheeptha

We demonstrate hydrothermal (300 degrees C, 10 MPa) catalytic conversion of real waste lipids (e.g., waste vegetable oil, sewer trap grease) to liquid hydrocarbon fuels without net need for external chemical inputs (e.g., H2 gas, methanol). A supported bimetallic catalyst (Pt-Re/C; 5 wt % of each metal) previously shown to catalyze both aqueous phase reforming of glycerol (a triacylglyceride lipid hydrolysis coproduct) to H2 gas and conversion of oleic and stearic acid, model unsaturated and saturated fatty acids, to linear alkanes was applied to process real waste lipid feedstocks in water. For reactions conducted with an initially inert headspace gasmore » (N2), waste vegetable oil (WVO) was fully converted into linear hydrocarbons (C15-C17) and other hydrolyzed byproducts within 4.5 h, and H2 gas production was observed. Addition of H2 to the initial reactor headspace accelerated conversion, but net H2 production was still observed, in agreement with results obtained for aqueous mixtures containing model fatty acids and glycerol. Conversion to liquid hydrocarbons with net H2 production was also observed for a range of other waste lipid feedstocks (animal fat residuals, sewer trap grease, dry distiller's grain oil, coffee oil residual). These findings demonstrate potential for valorization of waste lipids through conversion to hydrocarbons that are more compatible with current petroleum-based liquid fuels than the biodiesel and biogas products of conventional waste lipid processing technologies.« less

Renewable chemical feedstocks from integrated liquefaction processing of lingocellulosic materials using microwave energy

Treesearch

Junming Xu; Jianchun Jiang; Chung-Yun Hse; Todd F. Shupe

2012-01-01

The objective of this investigation was to find a simple method for the production of phenolic rich products and sugar derivatives (biopolyols) via separation of liquefied lingocellulosic materials. Liquefaction of lignocellulosic materials was conducted in methanol at 180 °C for 15 min with the conversion of raw materials at about 75%. After liquefaction, the...

Soil properties in 35 y old pine and hardwood plantations after conversion from mixed pine-hardwood forest

Treesearch

D. Andrew Scott; Michael G. Messina

2009-01-01

Past management practices have changed much of the native mixed pine-hardwood forests on upland alluvial terraces of the western Gulf Coastal Plain to either pine monocultures or hardwood (angiosperm) stands. Changes in dominant tree species can alter soil chemical, biological, and physical properties and processes, thereby changing soil attributes, and ultimately,...

Evaluation of a value prior to pulping-thermomechanical pulp business concept. Part 2.

Treesearch

Ted Bilek; Carl Houtman; Peter Ince

2011-01-01

Value Prior to Pulping (VPP) is a novel biorefining concept for pulp mills that includes hydrolysis extraction of hemicellulose wood sugars and acetic acid from pulpwood prior to pulping. The concept involves conversion of wood sugars via fermentation to fuel ethanol or other chemicals and the use of remaining solid wood material in the pulping process. This paper...

Development of a high temperature microbial fermentation process for butanol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeor, Jeffery D. St.; Reed, David W.; Daubaras, Dayna L.

2015-08-01

Transforming renewable biomass into cost-competitive high-performance biofuels and bioproducts is key to the U.S. future energy and chemical needs. Butanol production by microbial fermentation for chemical conversion to polyolefins, elastomers, drop-in jet or diesel fuel, and other chemicals is a promising solution. A high temperature fermentation process could decrease energy costs, capital cost, give higher butanol production, and allow for continuous fermentation. In this paper, we describe our approach to genetically transform Geobacillus caldoxylosiliticus, using a pUCG18 plasmid, for potential insertion of a butanol production pathway. Transformation methods tested were electroporation of electrocompetent cells, ternary conjugation with E. coli donormore » and helper strains, and protoplast fusion. These methods have not been successful using the current plasmid. Growth controls show cells survive the various methods tested, suggesting the possibility of transformation inhibition from a DNA restriction modification system in G. caldoxylosiliticus, as reported in the literature.« less

Foundations of atmospheric pressure non-equilibrium plasmas

NASA Astrophysics Data System (ADS)

Bruggeman, Peter J.; Iza, Felipe; Brandenburg, Ronny

2017-12-01

Non-equilibrium plasmas have been intensively studied over the past century in the context of material processing, environmental remediation, ozone generation, excimer lamps and plasma display panels. Research on atmospheric pressure non-equilibrium plasmas intensified over the last two decades leading to a large variety of plasma sources that have been developed for an extended application range including chemical conversion, medicine, chemical analysis and disinfection. The fundamental understanding of these discharges is emerging but there remain a lot of unexplained phenomena in these intrinsically complex plasmas. The properties of non-equilibrium plasmas at atmospheric pressure span over a huge range of electron densities as well as heavy particle and electron temperatures. This paper provides an overview of the key underlying processes that are important for the generation and stabilization of atmospheric pressure non-equilibrium plasmas. The unique physical and chemical properties of theses discharges are also summarized.

Time-resolved vibrational spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tokmakoff, Andrei; Champion, Paul; Heilweil, Edwin J.

2009-05-14

This document contains the Proceedings from the 14th International Conference on Time-Resolved Vibrational Spectroscopy, which was held in Meredith, NH from May 9-14, 2009. The study of molecular dynamics in chemical reaction and biological processes using time-resolved spectroscopy plays an important role in our understanding of energy conversion, storage, and utilization problems. Fundamental studies of chemical reactivity, molecular rearrangements, and charge transport are broadly supported by the DOE's Office of Science because of their role in the development of alternative energy sources, the understanding of biological energy conversion processes, the efficient utilization of existing energy resources, and the mitigation ofmore » reactive intermediates in radiation chemistry. In addition, time-resolved spectroscopy is central to all fiveof DOE's grand challenges for fundamental energy science. The Time-Resolved Vibrational Spectroscopy conference is organized biennially to bring the leaders in this field from around the globe together with young scientists to discuss the most recent scientific and technological advances. The latest technology in ultrafast infrared, Raman, and terahertz spectroscopy and the scientific advances that these methods enable were covered. Particular emphasis was placed on new experimental methods used to probe molecular dynamics in liquids, solids, interfaces, nanostructured materials, and biomolecules.« less

Kinetic conversion of CO to CH4 in the Solar System

NASA Technical Reports Server (NTRS)

Yung, Y. L.; Allen, M.; Pinto, J. P.

1991-01-01

Some of the most interesting chemistry in the Solar System involves changes in the oxidation state of the simple carbon species. The chemical pathways for the conversion of CH4 to CO and CO2 are for the most part known. The reverse process, the reduction of CO to CH4, is, however, poorly understood. This is surprising in view of the importance of the reduction process in the chemistry of the Solar System. Recently we investigated the chemical kinetics of a hitherto unsuspected reaction. It is argued that the formation of the methoxy radical (CH3O) from H+H2CO may play an essential role in the reduction of CO to CH4. The rate coefficient for this reaction has been estimated using the approximate theory of J. Troe and transition state theory. We will discuss the implications of this reaction for the chemistry of CO on Jupiter, in the solar nebula, for interpreting the laboratory experiments of A. Bar-Nun and A. Shaviv and A. Bar-Nun and S. Chang, and for organic synthesis in the prebiotic terrestrial atmosphere. The possible relation of CO reduction in the solar nebula and polyoxymethylene observed in comet Halley will be discussed.

UV irradiation study of a tripeptide isolated in an argon matrix: A tautomerism process evidenced by infrared and X-ray photoemission spectroscopies

NASA Astrophysics Data System (ADS)

Mateo-Marti, E.; Pradier, C. M.

2013-05-01

Matrix isolation is a powerful tool for studying photochemical processes occurring in isolated molecules. In this way, we characterized the chemical modifications occurring within a tri peptide molecule, IGF, when exposed to the influence of Ultraviolet (UV) irradiation. This paper first describes the successful formation of the tripeptide (IGF) argon matrix under vacuum conditions, followed by the in situ UV irradiation and characterization of the molecular matrix reactivity after UV-irradiation. These studies have been performed by combining two complementary spectroscopic techniques, Fourier-Transform Reflexion Absorption Spectroscopy (FT-IRRAS) and X-ray Photoelectron Spectroscopy (XPS). The IR spectra of the isolated peptide-matrix, before and after UV irradiation, revealed significant differences that could be associated either to a partial deprotonation of the molecule or to a tautomeric conversion of some amide bonds to imide ones on some peptide molecules. XPS analyses undoubtedly confirmed the second hypothesis; the combination of IRRAS and XPS results provide evidence that UV irradiation of peptides induces a chemical reaction, namely a shift of the double bond, meaning partial conversion from amide tautomer into an imidic acid tautomer.

Recommendation of ruthenium source for sludge batch flowsheet studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woodham, W.

Included herein is a preliminary analysis of previously-generated data from sludge batches 7a, 7b, 8, and 9 sludge simulant and real-waste testing, performed to recommend a form of ruthenium for future sludge batch simulant testing under the nitric-formic flowsheet. Focus is given to reactions present in the Sludge Receipt and Adjustment Tank cycle, given that this cycle historically produces the most changes in chemical composition during Chemical Process Cell processing. Data is presented and analyzed for several runs performed under the nitric-formic flowsheet, with consideration given to effects on the production of hydrogen gas, nitrous oxide gas, consumption of formate,more » conversion of nitrite to nitrate, and the removal and recovery of mercury during processing. Additionally, a brief discussion is given to the effect of ruthenium source selection under the nitric-glycolic flowsheet. An analysis of data generated from scaled demonstration testing, sludge batch 9 qualification testing, and antifoam degradation testing under the nitric-glycolic flowsheet is presented. Experimental parameters of interest under the nitric-glycolic flowsheet include N2O production, glycolate destruction, conversion of glycolate to formate and oxalate, and the conversion of nitrite to nitrate. To date, the number of real-waste experiments that have been performed under the nitric-glycolic flowsheet is insufficient to provide a complete understanding of the effects of ruthenium source selection in simulant experiments with regard to fidelity to real-waste testing. Therefore, a determination of comparability between the two ruthenium sources as employed under the nitric-glycolic flowsheet is made based on available data in order to inform ruthenium source selection for future testing under the nitric-glycolic flowsheet.« less

Comparative evaluation of acid and alkaline sulfite pretreatments for enzymatic saccharification of bagasses from three different sugarcane hybrids.

PubMed

Monte, Joseana R; Laurito-Friend, Debora F; Ferraz, André; Milagres, Adriane M F

2018-04-26

Sugarcane bagasses from three experimental sugarcane hybrids and a mill-reference sample were used to compare the efficiency and mode of action of acid and alkaline sulfite pretreatment processes. Varied chemical loads and reaction temperatures were used to prepare samples with distinguished characteristics regarding xylan and lignin removals, as well as sulfonation levels of residual lignins. The pretreatment with low sulfite loads (5%) under acidic conditions (pH 2) provided maximum glucose yield of 70% during enzymatic hydrolysis with cellulases (10 FPU/g) and β-glucosidases (20 UI/g bagasse). In this case, glucan enzymatic conversion from pretreated materials was mostly associated with extensive xylan removal (70-100%) and partial delignification occurred during the pretreatment. The use of low sulfite loads under acidic conditions required pretreatment temperatures of 160°C. In contrast, at a lower pretreatment temperature (120°C), alkaline sulfite process achieved similar glucan digestibility, but required a higher sulfite load (7.5%). Residual xylans from acid pretreated materials were almost completely hydrolysed by commercial enzymes, contrasting with relatively lower xylan to xylose conversions observed in alkaline pretreated samples. Efficient xylan removal during acid sulfite pretreatment and also during enzymatic digestion can be useful to enhance glucan accessibility and digestibility by cellulases. Alkaline sulfite process also provided substrates with high glucan digestibility, mainly associated with delignification and sulfonation of residual lignins. The results demonstrate that temperature, pH and sulfite can be combined for reducing lignocellulose recalcitrance and achieve similar glucan conversion rates in the alkaline and acid sulfite pretreated bagasses. This article is protected by copyright. All rights reserved. © 2018 American Institute of Chemical Engineers.

Time-Resolved Quantum Cascade Laser Absorption Spectroscopy of Pulsed Plasma Assisted Chemical Vapor Deposition Processes Containing BCl3

NASA Astrophysics Data System (ADS)

Lang, Norbert; Hempel, Frank; Strämke, Siegfried; Röpcke, Jürgen

2011-08-01

In situ measurements are reported giving insight into the plasma chemical conversion of the precursor BCl3 in industrial applications of boriding plasmas. For the online monitoring of its ground state concentration, quantum cascade laser absorption spectroscopy (QCLAS) in the mid-infrared spectral range was applied in a plasma assisted chemical vapor deposition (PACVD) reactor. A compact quantum cascade laser measurement and control system (Q-MACS) was developed to allow a flexible and completely dust-sealed optical coupling to the reactor chamber of an industrial plasma surface modification system. The process under the study was a pulsed DC plasma with periodically injected BCl3 at 200 Pa. A synchronization of the Q-MACS with the process control unit enabled an insight into individual process cycles with a sensitivity of 10-6 cm-1·Hz-1/2. Different fragmentation rates of the precursor were found during an individual process cycle. The detected BCl3 concentrations were in the order of 1014 molecules·cm-3. The reported results of in situ monitoring with QCLAS demonstrate the potential for effective optimization procedures in industrial PACVD processes.

Plasma for electrification of chemical industry: a case study on CO2 reduction

NASA Astrophysics Data System (ADS)

van Rooij, G. J.; Akse, H. N.; Bongers, W. A.; van de Sanden, M. C. M.

2018-01-01

Significant growth of the share of (intermittent) renewable power in the chemical industry is imperative to meet increasingly stricter limits on CO2 exhaust that are being implemented within Europe. This paper aims to evaluate the potential of a plasma process that converts input CO2 into a pure stream of CO to aid in renewable energy penetration in this sector. A realistic process design is constructed to serve as a basis for an economical analysis. The manufacturing cost price of CO is estimated at 1.2 kUS ton-1 CO. A sensitivity analysis shows that separation is the dominant cost factor, so that improving conversion is currently more effective to lower the price than e.g. energy efficiency.

Cogeneration Technology Alternatives Study (CTAS). Volume 4: Energy conversion systems

NASA Technical Reports Server (NTRS)

Brown, D. H.; Gerlaugh, H. E.; Priestley, R. R.

1980-01-01

Industrial processes from the largest energy consuming sectors were used as a basis for matching a similar number of energy conversion systems that are considered as candidate which can be made available by the 1985 to 2000 time period. The sectors considered included food, textiles, lumber, paper, chemicals, petroleum, glass, and primary metals. The energy conversion systems included steam and gas turbines, diesels, thermionics, stirling, closed-cycle and steam injected gas turbines, and fuel cells. Fuels considered were coal, both coal and petroleum-based residual and distillate liquid fuels, and low Btu gas obtained through the on-site gasification of coal. An attempt was made to use consistent assumptions and a consistent set of ground rules specified by NASA for determining performance and cost. The advanced and commercially available cogeneration energy conversion systems studied in CTAS are fined together with their performance, capital costs, and the research and developments required to bring them to this level of performance.

Evaluation of coal-related model compounds using a tandem mass spectrometry.

PubMed

Li, Guo-Sheng; Dong, Xueming; Fan, Xing; You, Chun-Yan; Wu, Ge; Zhao, Yun-Peng; Lu, Yao; Wei, Xian-Yong; Ma, Feng-Yun

2018-05-08

Gas chromotography/mass spectrometry (GC/MS) is a routine and basic instrumental method for the analysis of complex coal conversion products in chemical industry. To further enhance practical potentials of GC/MS in chemical industry, a tandem MS method for the selection of ion pair applied in monitoring coal conversions was established by using GC/quadrupole time-of-flight MS (GC/Q-TOF MS). The corresponding fragmentation pathways were explored and suitable ion pairs were screened. Fourteen coal-related model compounds (CRMCs) were analyzed using a GC/Q-TOF MS with different collision induced dissociation (CID) energies (5-20 eV). The fragmentation pathways can offer a better understanding of chemical bond breaking, hydrogen transfer, rearrangement reactions and elimination of neutral fragments for CRMCs during the CID process. The precursor ions of aromatic hydrocarbons without alkyl chain were hard to fragment with a CID energy of 20 eV. But aromatic hydrocarbons with branched chains were prone to fragment via the loss of alkyl chains and further fragmented through ring-open reactions. Compared to C alk -C ar bond, C ar -C ar bond was hard to fragment duo to its high bond dissociation energy. The existence of heteroatoms facilitated fragmentation that was conducive to screening ion pair. The CID technique of GC/Q-TOF MS will contribute to the studies on the organic composition of coals and building monitoring methods for coal conversions via fragmentation and ion pair selection. This article is protected by copyright. All rights reserved.

High performance catalytic distillation using CNTs-based holistic catalyst for production of high quality biodiesel

PubMed Central

Zhang, Dongdong; Wei, Dali; Li, Qi; Ge, Xin; Guo, Xuefeng; Xie, Zaiku; Ding, Weiping

2014-01-01

For production of biodiesel from bio oils by heterogeneous catalysis, high performance catalysts of transesterification and the further utilization of glycerol have been the two points of research. The process seemed easy, however, has never been well established. Here we report a novel design of catalytic distillation using hierachically integrated CNTs-based holistic catalyst to figure out the two points in one process, which shows high performance both for the conversion of bio oils to biodiesel and, unexpectedly, for the conversion of glycerol to more valuable chemicals at the same time. The method, with integration of nano, meso to macro reactor, has overwhelming advantages over common technologies using liquid acids or bases to catalyze the reactions, which suffer from the high cost of separation and unsolved utilization of glycerol. PMID:24503897

High performance catalytic distillation using CNTs-based holistic catalyst for production of high quality biodiesel

NASA Astrophysics Data System (ADS)

Zhang, Dongdong; Wei, Dali; Li, Qi; Ge, Xin; Guo, Xuefeng; Xie, Zaiku; Ding, Weiping

2014-02-01

For production of biodiesel from bio oils by heterogeneous catalysis, high performance catalysts of transesterification and the further utilization of glycerol have been the two points of research. The process seemed easy, however, has never been well established. Here we report a novel design of catalytic distillation using hierachically integrated CNTs-based holistic catalyst to figure out the two points in one process, which shows high performance both for the conversion of bio oils to biodiesel and, unexpectedly, for the conversion of glycerol to more valuable chemicals at the same time. The method, with integration of nano, meso to macro reactor, has overwhelming advantages over common technologies using liquid acids or bases to catalyze the reactions, which suffer from the high cost of separation and unsolved utilization of glycerol.

Plant hydrocarbon recovery process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dzadzic, P.M.; Price, M.C.; Shih, C.J.

1982-01-26

A process for production and recovery of hydrocarbons from hydrocarbon-containing whole plants in a form suitable for use as chemical feedstocks or as hydrocarbon energy sources which process comprises: (A) pulverizing by grinding or chopping hydrocarbon-containing whole plants selected from the group consisting of euphorbiaceae, apocynaceae, asclepiadaceae, compositae, cactaceae and pinaceae families to a suitable particle size, (B) drying and preheating said particles in a reducing atmosphere under positive pressure (C) passing said particles through a thermal conversion zone containing a reducing atmosphere and with a residence time of 1 second to about 30 minutes at a temperature within themore » range of from about 200* C. To about 1000* C., (D) separately recovering the condensable vapors as liquids and the noncondensable gases in a condition suitable for use as chemical feedstocks or as hydrocarbon fuels.« less

Efficient ethanol production from dried oil palm trunk treated by hydrothermolysis and subsequent enzymatic hydrolysis.

PubMed

Eom, In-Yong; Yu, Ju-Hyun; Jung, Chan-Duck; Hong, Kyung-Sik

2015-01-01

Oil palm trunk (OPT) is a valuable bioresource for the biorefinery industry producing biofuels and biochemicals. It has the distinct feature of containing a large amount of starch, which, unlike cellulose, can be easily solubilized by water when heated and hydrolyzed to glucose by amylolytic enzymes without pretreatment for breaking down the biomass recalcitrance. Therefore, it is suggested as beneficial to extract most of the starch from OPT through autoclaving and subsequent amylolytic hydrolysis prior to pretreatment. However, this treatment requires high capital and operational costs, and there could be a high probability of microbial contamination during starch processing. In terms of biochemical conversion of OPT, this study aimed to develop a simple and efficient ethanol conversion process without any chemical use such as acids and bases or detoxification. For comparison with the proposed efficient ethanol conversion process, OPT was subjected to hydrothermal treatment at 180 °C for 30 min. After enzymatic hydrolysis of PWS, 43.5 g of glucose per 100 g dry biomass was obtained, which corresponds to 81.3 % of the theoretical glucose yield. Through subsequent alcohol fermentation, 81.4 % ethanol yield of the theoretical ethanol yield was achieved. To conduct the proposed new process, starch in OPT was converted to ethanol through enzymatic hydrolysis and subsequent fermentation prior to hydrothermal treatment, and the resulting slurry was subjected to identical processes that were applied to control. Consequently, a high-glucose yield of 96.3 % was achieved, and the resulting ethanol yield was 93.5 %. The proposed new process was a simple method for minimizing the loss of starch during biochemical conversion and maximizing ethanol production as well as fermentable sugars from OPT. In addition, this methodology offers the advantage of reducing operational and capital costs due to minimizing the process for ethanol production by excluding expensive processes related to detoxification prior to enzymatic hydrolysis and fermentation such as washing/conditioning and solid-liquid separation of pretreated slurry. The potential future use of xylose-digestible microorganisms could further increase the ethanol yield from the proposed process, thereby increasing its effectiveness for the conversion of OPT into biofuels and biochemicals.

Engineering a more sustainable world through catalysis and green chemistry.

PubMed

Sheldon, Roger A

2016-03-01

The grand challenge facing the chemical and allied industries in the twenty-first century is the transition to greener, more sustainable manufacturing processes that efficiently use raw materials, eliminate waste and avoid the use of toxic and hazardous materials. It requires a paradigm shift from traditional concepts of process efficiency, focusing on chemical yield, to one that assigns economic value to replacing fossil resources with renewable raw materials, eliminating waste and avoiding the use of toxic and/or hazardous substances. The need for a greening of chemicals manufacture is readily apparent from a consideration of the amounts of waste generated per kilogram of product (the E factors) in various segments of the chemical industry. A primary source of this waste is the use of antiquated 'stoichiometric' technologies and a major challenge is to develop green, catalytic alternatives. Another grand challenge for the twenty-first century, driven by the pressing need for climate change mitigation, is the transition from an unsustainable economy based on fossil resources--oil, coal and natural gas--to a sustainable one based on renewable biomass. In this context, the valorization of waste biomass, which is currently incinerated or goes to landfill, is particularly attractive. The bio-based economy involves cross-disciplinary research at the interface of biotechnology and chemical engineering, focusing on the development of green, chemo- and biocatalytic technologies for waste biomass conversion to biofuels, chemicals and bio-based materials. Biocatalysis has many benefits to offer in this respect. The catalyst is derived from renewable biomass and is biodegradable. Processes are performed under mild conditions and generally produce less waste and are more energy efficient than conventional ones. Thanks to modern advances in biotechnology 'tailor-made' enzymes can be economically produced on a large scale. However, for economic viability it is generally necessary to recover and re-use the enzyme and this can be achieved by immobilization, e.g. as solid cross-linked enzyme aggregates (CLEAs), enabling separation by filtration or centrifugation. A recent advance is the use of 'smart', magnetic CLEAs, which can be separated magnetically from reaction mixtures containing suspensions of solids; truly an example of cross-disciplinary research at the interface of physical and life sciences, which is particularly relevant to biomass conversion processes. © 2016 The Author(s).

Engineering a more sustainable world through catalysis and green chemistry

PubMed Central

2016-01-01

The grand challenge facing the chemical and allied industries in the twenty-first century is the transition to greener, more sustainable manufacturing processes that efficiently use raw materials, eliminate waste and avoid the use of toxic and hazardous materials. It requires a paradigm shift from traditional concepts of process efficiency, focusing on chemical yield, to one that assigns economic value to replacing fossil resources with renewable raw materials, eliminating waste and avoiding the use of toxic and/or hazardous substances. The need for a greening of chemicals manufacture is readily apparent from a consideration of the amounts of waste generated per kilogram of product (the E factors) in various segments of the chemical industry. A primary source of this waste is the use of antiquated ‘stoichiometric’ technologies and a major challenge is to develop green, catalytic alternatives. Another grand challenge for the twenty-first century, driven by the pressing need for climate change mitigation, is the transition from an unsustainable economy based on fossil resources—oil, coal and natural gas—to a sustainable one based on renewable biomass. In this context, the valorization of waste biomass, which is currently incinerated or goes to landfill, is particularly attractive. The bio-based economy involves cross-disciplinary research at the interface of biotechnology and chemical engineering, focusing on the development of green, chemo- and biocatalytic technologies for waste biomass conversion to biofuels, chemicals and bio-based materials. Biocatalysis has many benefits to offer in this respect. The catalyst is derived from renewable biomass and is biodegradable. Processes are performed under mild conditions and generally produce less waste and are more energy efficient than conventional ones. Thanks to modern advances in biotechnology ‘tailor-made’ enzymes can be economically produced on a large scale. However, for economic viability it is generally necessary to recover and re-use the enzyme and this can be achieved by immobilization, e.g. as solid cross-linked enzyme aggregates (CLEAs), enabling separation by filtration or centrifugation. A recent advance is the use of ‘smart’, magnetic CLEAs, which can be separated magnetically from reaction mixtures containing suspensions of solids; truly an example of cross-disciplinary research at the interface of physical and life sciences, which is particularly relevant to biomass conversion processes. PMID:27009181

Particle morphology characterization and manipulation in biomass slurries and the effect on rheological properties and enzymatic conversion.

PubMed

Dibble, Clare J; Shatova, Tatyana A; Jorgenson, Jennie L; Stickel, Jonathan J

2011-01-01

An improved understanding of how particle size distribution relates to enzymatic hydrolysis performance and rheological properties could enable enhanced biochemical conversion of lignocellulosic feedstocks. Particle size distribution can change as a result of either physical or chemical manipulation of a biomass sample. In this study, we employed image processing techniques to measure slurry particle size distribution and validated the results by showing that they are comparable to those from laser diffraction and sieving. Particle size and chemical changes of biomass slurries were manipulated independently and the resulting yield stress and enzymatic digestibility of slurries with different size distributions were measured. Interestingly, reducing particle size by mechanical means from about 1 mm to 100 μm did not reduce the yield stress of the slurries over a broad range of concentrations or increase the digestibility of the biomass over the range of size reduction studied here. This is in stark contrast to the increase in digestibility and decrease in yield stress when particle size is reduced by dilute-acid pretreatment over similar size ranges. Copyright © 2011 American Institute of Chemical Engineers (AIChE).

A Conversation with James J. Morgan

NASA Astrophysics Data System (ADS)

Morgan, James J.; Newman, Dianne K.

2015-05-01

In conversation with professor Dianne Newman, Caltech geobiologist, James "Jim" J. Morgan recalls his early days in Ireland and New York City, education in parochial and public schools, and introduction to science in Cardinal Hayes High School, Bronx. In 1950, Jim entered Manhattan College, where he elected study of civil engineering, in particular water quality. Donald O'Connor motivated Jim's future study of O2 in rivers at Michigan, where in his MS work he learned to model O2 dynamics of rivers. As an engineering instructor at Illinois, Jim worked on rivers polluted by synthetic detergents. He chose to focus on chemical studies, seeing it as crucial for the environment. Jim enrolled for PhD studies with Werner Stumm at Harvard, who mentored his research in chemistry of particle coagulation and oxidation processes of Mn(II) and (IV). In succeeding decades, until retirement in 2000, Jim's teaching and research centered on aquatic chemistry; major themes comprised rates of abiotic manganese oxidation on particle surfaces and flocculation of natural water particles, and chemical speciation proved the key.

100 years of microbial electricity production: three concepts for the future

PubMed Central

Arends, Jan B. A.; Verstraete, Willy

2012-01-01

Summary Bioelectrochemical systems (BES) have been explored according to three main concepts: to produce energy from organic substrates, to generate products and to provide specific environmental services. In this work, by using an engineering approach, biological conversion rates are calculated for BES resp. anaerobic digestion. These rates are compared with currents produced by chemical batteries and chemical fuel cells in order to position BES in the ‘energy’‐market. To evaluate the potential of generating various products, the biochemistry behind the biological conversion rates is examined in relation to terminal electron transfer molecules. By comparing kinetics rather than thermodynamics, more insight is gained in the biological bottlenecks that hamper a BES. The short‐term future for BES research and its possible application is situated in smart niches in sustainable environmental development, i.e. in processes where no large currents or investment cost intensive reactors are needed to obtain the desired results. Some specific examples are identified. PMID:21958308

Biomass recalcitrance: a multi-scale, multi-factor, and conversion-specific property.

PubMed

McCann, Maureen C; Carpita, Nicholas C

2015-07-01

Recalcitrance of plant biomass to enzymatic hydrolysis for biofuel production is thought to be a property conferred by lignin or lignin-carbohydrate complexes. However, chemical catalytic and thermochemical conversion pathways, either alone or in combination with biochemical and fermentative pathways, now provide avenues to utilize lignin and to expand the product range beyond ethanol or butanol. To capture all of the carbon in renewable biomass, both lignin-derived aromatics and polysaccharide-derived sugars need to be transformed by catalysts to liquid hydrocarbons and high-value co-products. We offer a new definition of recalcitrance as those features of biomass which disproportionately increase energy requirements in conversion processes, increase the cost and complexity of operations in the biorefinery, and/or reduce the recovery of biomass carbon into desired products. The application of novel processing technologies applied to biomass reveal new determinants of recalcitrance that comprise a broad range of molecular, nanoscale, and macroscale factors. Sampling natural genetic diversity within a species, transgenic approaches, and synthetic biology approaches are all strategies that can be used to select biomass for reduced recalcitrance in various pretreatments and conversion pathways. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

75 FR 59727 - National Center for Environmental Health/Agency for Toxic Substances and Disease Registry (NCEH...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-28

... National Conversation on Public Health and Chemical Exposures Leadership Council Meeting Time and Date: 9 a... Chemical Exposures Leadership Council, which is convened by RESOLVE, a non-profit independent facilitator... exposures. The Leadership Council provides overall guidance to the National Conversation project and is...

Biotechnology for producing fuels and chemicals from biomass. Volume 2: Fermentation chemicals from biomass

NASA Astrophysics Data System (ADS)

Villet, R.

1981-02-01

The technological and economic feasibility of producing chemicals by fermentation is discussed: acetone; butanol; acetic acid; citric acid; 2,3-butanediol, and propionic acid. Improved cost of fermentative production will hinge on improving yields and using cellulosic feedstocks. The market for acetic acid is likely to grow 5 percent to 7 percent/yr. A potential process for production is the fermentation of hydrolyzed cellulosic material to ethanol followed by chemical conversion to acetic acid. The feedstock cost is 15 to 20 percent of the overall cost of production. The anticipated 5 percent growth in demand for citric acid could be enhanced by using it to displace phosphates in detergent manufacture. A number of useful chemicals can be derived from 2,3-butanediol, which has not been produced commercially on a large scale. The commercial fermentative production of propionic acid has not yet been developed.

Role of modern chemistry in sustainable arable crop protection.

PubMed

Smith, Keith; Evans, David A; El-Hiti, Gamal A

2008-02-12

Organic chemistry has been, and for the foreseeable future will remain, vitally important for crop protection. Control of fungal pathogens, insect pests and weeds is crucial to enhanced food provision. As world population continues to grow, it is timely to assess the current situation, anticipate future challenges and consider how new chemistry may help meet those challenges. In future, agriculture will increasingly be expected to provide not only food and feed, but also crops for conversion into renewable fuels and chemical feedstocks. This will further increase the demand for higher crop yields per unit area, requiring chemicals used in crop production to be even more sophisticated. In order to contribute to programmes of integrated crop management, there is a requirement for chemicals to display high specificity, demonstrate benign environmental and toxicological profiles, and be biodegradable. It will also be necessary to improve production of those chemicals, because waste generated by the production process mitigates the overall benefit. Three aspects are considered in this review: advances in the discovery process for new molecules for sustainable crop protection, including tests for environmental and toxicological properties as well as biological activity; advances in synthetic chemistry that may offer efficient and environmentally benign manufacturing processes for modern crop protection chemicals; and issues related to energy use and production through agriculture.

Hybrid Inorganic/Organic Photovoltaics: Translating Fundamental Nanostructure Research to Enhanced Solar Conversion Efficiency

DTIC Science & Technology

2010-03-18

quantum dots composed of a photopolymerizable outer corona constituting methacrylate and an inner siloxane layer, with a view making them photo...nanostructures. The inherent properties of photopolymerizable QDs such as their stability, PL, and ease of solution processability, make them suitable...Thiophenes are important compounds that are used as building blocks in many chemical synthesis. The thiophene oligomers and thiophene-based

Advancing the frontiers in nanocatalysis, biointerfaces, and renewable energy conversion by innovations of surface techniques.

PubMed

Somorjai, Gabor A; Frei, Heinz; Park, Jeong Y

2009-11-25

The challenge of chemistry in the 21st century is to achieve 100% selectivity of the desired product molecule in multipath reactions ("green chemistry") and develop renewable energy based processes. Surface chemistry and catalysis play key roles in this enterprise. Development of in situ surface techniques such as high-pressure scanning tunneling microscopy, sum frequency generation (SFG) vibrational spectroscopy, time-resolved Fourier transform infrared methods, and ambient pressure X-ray photoelectron spectroscopy enabled the rapid advancement of three fields: nanocatalysts, biointerfaces, and renewable energy conversion chemistry. In materials nanoscience, synthetic methods have been developed to produce monodisperse metal and oxide nanoparticles (NPs) in the 0.8-10 nm range with controlled shape, oxidation states, and composition; these NPs can be used as selective catalysts since chemical selectivity appears to be dependent on all of these experimental parameters. New spectroscopic and microscopic techniques have been developed that operate under reaction conditions and reveal the dynamic change of molecular structure of catalysts and adsorbed molecules as the reactions proceed with changes in reaction intermediates, catalyst composition, and oxidation states. SFG vibrational spectroscopy detects amino acids, peptides, and proteins adsorbed at hydrophobic and hydrophilic interfaces and monitors the change of surface structure and interactions with coadsorbed water. Exothermic reactions and photons generate hot electrons in metal NPs that may be utilized in chemical energy conversion. The photosplitting of water and carbon dioxide, an important research direction in renewable energy conversion, is discussed.

Gas-to-particle conversion in the particle precipitation-aided chemical vapor deposition process II. Synthesis of the perovskite oxide yttrium chromite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dieten, V.E.J. van; Dekker, J.P.; Hurkmans, E.J.

1993-11-01

In the particle precipitation-aided chemical vapor deposition process, an aerosol is formed in the gas phase at elevated temperatures. The particles are deposited on a cooled substrate. Coherent layers with a controlled porosity can be obtained by a simultaneous heterogeneous reaction, which interconnects the deposited particles. The synthesis of submicrometer powder of the perovskite oxide yttrium chromite (YCrO[sub 3]) by gas to particle conversion, which is the first step of the PP-CVD process, has been investigated, and preliminary results are shown. The powders have been synthesized using yttrium trichloride vapor (YCl[sub 3]), chromium trichloride vapor (CrCl[sub 3]), and steam andmore » oxygen as reactants. The influence of the input molar ratio of the elements on the composition and characteristics of the powders has been investigated. Phase composition has been determined by X-ray diffraction (XRD). The powders have been characterized by transmission electron microscopy (TEM) and sedimentation field flow fractionation (SF[sup 3]). At a reaction temperature of 1283 K the powders consist of the chromium sesquioxide (Cr[sub 2]O[sub 3]), or a mixture of Cr[sub 2]O[sub 3] and YCrO[sub 3]. At stoichiometeric input amounts of metal chlorides and steam the formation of YCrO[sub 3] seems to be favored. 19 refs., 6 figs., 3 tabs.« less

Relationship between femtosecond-picosecond dynamics to enzyme catalyzed H-transfer

PubMed Central

Cheatum, Christopher M.; Kohen, Amnon

2015-01-01

At physiological temperatures, enzymes exhibit a broad spectrum of conformations, which interchange via thermally activated dynamics. These conformations are sampled differently in different complexes of the protein and its ligands, and the dynamics of exchange between these conformers depends on the mass of the group that is moving and the length scale of the motion, as well as restrictions imposed by the globular fold of the enzymatic complex. Many of these motions have been examined and their role in the enzyme function illuminated, yet most experimental tools applied so far have identified dynamics at time scales of seconds to nanoseconds, which are much slower than the time scale for H-transfer between two heavy atoms. This chemical conversion and other processes involving cleavage of covalent bonds occur on picosecond to femtosecond time scales, where slower processes mask both the kinetics and dynamics. Here we present a combination of kinetic and spectroscopic methods that may enable closer examination of the relationship between enzymatic C-H→C transfer and the dynamics of the active site environment at the chemically relevant time scale. These methods include kinetic isotope effects and their temperature dependence, which are used to study the kinetic nature of the H-transfer, and 2D IR spectroscopy, which is used to study the dynamics of transition-state- and ground-state-analog complexes. The combination of these tools is likely to provide a new approach to examine the protein dynamics that directly influence the chemical conversion catalyzed by enzymes. PMID:23539379

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drs. Mark E. Zapp; Todd French; Lewis Brown

The Mississippi Consortium for the Utilization of Biomass was formed via funding from the US Department of Energy's EPSCoR Program, which is administered by the Office of Basic Science. Funding was approved in July of 1999 and received by participating Mississippi institutions by 2000. The project was funded via two 3-year phases of operation (the second phase was awarded based on the high merits observed from the first 3-year phase), with funding ending in 2007. The mission of the Consortium was to promote the utilization of biomass, both cultured and waste derived, for the production of commodity and specialty chemicals.more » These scientific efforts, although generally basic in nature, are key to the development of future industries within the Southeastern United States. In this proposal, the majority of the efforts performed under the DOE EPSCoR funding were focused primarily toward the production of ethanol from lignocellulosic feedstocks and biogas from waste products. However, some of the individual projects within this program investigated the production of other products from biomass feeds (i.e. acetic acid and biogas) along with materials to facilitate the more efficient production of chemicals from biomass. Mississippi is a leading state in terms of raw biomass production. Its top industries are timber, poultry production, and row crop agriculture. However, for all of its vast amounts of biomass produced on an annual basis, only a small percentage of the biomass is actually industrially produced into products, with the bulk of the biomass being wasted. This situation is actually quite representative of many Southeastern US states. The research and development efforts performed attempted to further develop promising chemical production techniques that use Mississippi biomass feedstocks. The three processes that were the primary areas of interest for ethanol production were syngas fermentation, acid hydrolysis followed by hydrolyzate fermentation, and enzymatic conversion. All three of these processes are of particular interest to states in the Southeastern US since the agricultural products produced in this region are highly variable in terms of actual crop, production quantity, and the ability of land areas to support a particular type of crop. This greatly differs from the Midwestern US where most of this region's agricultural land supports one to two primary crops, such as corn and soybean. Therefore, developing processes which are relatively flexible in terms of biomass feedstock is key to the southeastern region of the US if this area is going to be a 'player' in the developing biomass to chemicals arena. With regard to the fermentation of syngas, research was directed toward developing improved biocatalysts through organism discovery and optimization, improving ethanol/acetic acid separations, evaluating potential bacterial contaminants, and assessing the use of innovative fermentors that are better suited for supporting syngas fermentation. Acid hydrolysis research was directed toward improved conversion yields and rates, acid recovery using membranes, optimization of fermenting organisms, and hydrolyzate characterization with changing feedstocks. Additionally, a series of development efforts addressed novel separation techniques for the separation of key chemicals from fermentation activities. Biogas related research focused on key factors hindering the widespread use of digester technologies in non-traditional industries. The digestion of acetic acids and other fermentation wastewaters was studied and methods used to optimize the process were undertaken. Additionally, novel laboratory methods were designed along with improved methods of digester operation. A search for better performing digester consortia was initiated coupled with improved methods to initiate their activity within digester environments. The third activity of the consortium generally studied the production of 'other' chemicals from waste biomass materials found in Mississippi. The two primary examples of this activity are production of chemical feedstocks from lignin and the production of high valued lipids from wastewater treatment sludges. Lignin conversion research, done in collaboration with DOE's National Renewable Energy Laboratory (NREL), studied ligninases derived from bacteria found within the gut of wood degrading insects, such as termites and the Betsey beetle. This research attempted to use these enzymes to reduce lignin down to aromatic chemicals capable of chemical conversation for production of value-added chemicals. The biodiesel efforts attempted to development economically viable methods for the separation of lipids from wastewater bacteria (which make up the bulk of sewage sludge) which were then converted to biodisel.« less

State of Practice for Emerging Waste Conversion Technologies

EPA Science Inventory

New technologies to convert municipal and other waste streams into fuels and chemical commodities, termed conversion technologies, are rapidly developing. Conversion technologies are garnering increasing interest and demand due primarily to alternative energy initiatives. These t...

A photocatalyst-enzyme coupled artificial photosynthesis system for solar energy in production of formic acid from CO2.

PubMed

Yadav, Rajesh K; Baeg, Jin-Ook; Oh, Gyu Hwan; Park, No-Joong; Kong, Ki-jeong; Kim, Jinheung; Hwang, Dong Won; Biswas, Soumya K

2012-07-18

The photocatalyst-enzyme coupled system for artificial photosynthesis process is one of the most promising methods of solar energy conversion for the synthesis of organic chemicals or fuel. Here we report the synthesis of a novel graphene-based visible light active photocatalyst which covalently bonded the chromophore, such as multianthraquinone substituted porphyrin with the chemically converted graphene as a photocatalyst of the artificial photosynthesis system for an efficient photosynthetic production of formic acid from CO(2). The results not only show a benchmark example of the graphene-based material used as a photocatalyst in general artificial photosynthesis but also the benchmark example of the selective production system of solar chemicals/solar fuel directly from CO(2).

Succinic acid production on xylose-enriched biorefinery streams by Actinobacillus succinogenes in batch fermentation

DOE PAGES

Salvachua, Davinia; Mohagheghi, Ali; Smith, Holly; ...

2016-02-02

Co-production of chemicals from lignocellulosic biomass alongside fuels holds promise for improving the economic outlook of integrated biorefineries. In current biochemical conversion processes that use thermochemical pretreatment and enzymatic hydrolysis, fractionation of hemicellulose-derived and cellulose-derived sugar streams is possible using hydrothermal or dilute acid pretreatment (DAP), which then offers a route to parallel trains for fuel and chemical production from xylose- and glucose-enriched streams. Succinic acid (SA) is a co-product of particular interest in biorefineries because it could potentially displace petroleum-derived chemicals and polymer precursors for myriad applications. Furthermore, SA production from biomass-derived hydrolysates has not yet been fully exploredmore » or developed.« less

Technologies for Upgrading Light Water Reactor Outlet Temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daniel S. Wendt; Piyush Sabharwall; Vivek Utgikar

Nuclear energy could potentially be utilized in hybrid energy systems to produce synthetic fuels and feedstocks from indigenous carbon sources such as coal and biomass. First generation nuclear hybrid energy system (NHES) technology will most likely be based on conventional light water reactors (LWRs). However, these LWRs provide thermal energy at temperatures of approximately 300°C, while the desired temperatures for many chemical processes are much higher. In order to realize the benefits of nuclear hybrid energy systems with the current LWR reactor fleets, selection and development of a complimentary temperature upgrading technology is necessary. This paper provides an initial assessmentmore » of technologies that may be well suited toward LWR outlet temperature upgrading for powering elevated temperature industrial and chemical processes during periods of off-peak power demand. Chemical heat transformers (CHTs) are a technology with the potential to meet LWR temperature upgrading requirements for NHESs. CHTs utilize chemical heat of reaction to change the temperature at which selected heat sources supply or consume thermal energy. CHTs could directly utilize LWR heat output without intermediate mechanical or electrical power conversion operations and the associated thermodynamic losses. CHT thermal characteristics are determined by selection of the chemical working pair and operating conditions. This paper discusses the chemical working pairs applicable to LWR outlet temperature upgrading and the CHT operating conditions required for providing process heat in NHES applications.« less

Claisen thermally rearranged (CTR) polymers

PubMed Central

Tena, Alberto; Rangou, Sofia; Shishatskiy, Sergey; Filiz, Volkan; Abetz, Volker

2016-01-01

Thermally rearranged (TR) polymers, which are considered the next-generation of membrane materials because of their excellent transport properties and high thermal and chemical stability, are proven to have significant drawbacks because of the high temperature required for the rearrangement and low degree of conversion during this process. We demonstrate that using a [3,3]-sigmatropic rearrangement, the temperature required for the rearrangement of a solid glassy polymer was reduced by 200°C. Conversions of functionalized polyimide to polybenzoxazole of more than 97% were achieved. These highly mechanically stable polymers were almost five times more permeable and had more than two times higher degrees of conversion than the reference polymer treated under the same conditions. Properties of these second-generation TR polymers provide the possibility of preparing efficient polymer membranes in a form of, for example, thin-film composite membranes for various gas and liquid membrane separation applications. PMID:27482538

Claisen thermally rearranged (CTR) polymers.

PubMed

Tena, Alberto; Rangou, Sofia; Shishatskiy, Sergey; Filiz, Volkan; Abetz, Volker

2016-07-01

Thermally rearranged (TR) polymers, which are considered the next-generation of membrane materials because of their excellent transport properties and high thermal and chemical stability, are proven to have significant drawbacks because of the high temperature required for the rearrangement and low degree of conversion during this process. We demonstrate that using a [3,3]-sigmatropic rearrangement, the temperature required for the rearrangement of a solid glassy polymer was reduced by 200°C. Conversions of functionalized polyimide to polybenzoxazole of more than 97% were achieved. These highly mechanically stable polymers were almost five times more permeable and had more than two times higher degrees of conversion than the reference polymer treated under the same conditions. Properties of these second-generation TR polymers provide the possibility of preparing efficient polymer membranes in a form of, for example, thin-film composite membranes for various gas and liquid membrane separation applications.

Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry.

PubMed

van den Bekerom, Dirk; den Harder, Niek; Minea, Teofil; Gatti, Nicola; Linares, Jose Palomares; Bongers, Waldo; van de Sanden, Richard; van Rooij, Gerard

2017-08-01

A flowing microwave plasma based methodology for converting electric energy into internal and/or translational modes of stable molecules with the purpose of efficiently driving non-equilibrium chemistry is discussed. The advantage of a flowing plasma reactor is that continuous chemical processes can be driven with the flexibility of startup times in the seconds timescale. The plasma approach is generically suitable for conversion/activation of stable molecules such as CO2, N2 and CH4. Here the reduction of CO2 to CO is used as a model system: the complementary diagnostics illustrate how a baseline thermodynamic equilibrium conversion can be exceeded by the intrinsic non-equilibrium from high vibrational excitation. Laser (Rayleigh) scattering is used to measure the reactor temperature and Fourier Transform Infrared Spectroscopy (FTIR) to characterize in situ internal (vibrational) excitation as well as the effluent composition to monitor conversion and selectivity.

Study of traits and recalcitrance reduction of field-grown COMT down-regulated switchgrass

DOE PAGES

Li, Mi; Pu, Yunqiao; Yoo, Chang Geun; ...

2017-01-03

The native recalcitrance of plants hinders the biomass conversion process using current biorefinery techniques. Down-regulation of the caffeic acid O-methyltransferase (COMT) gene in the lignin biosynthesis pathway of switchgrass reduced the thermochemical and biochemical conversion recalcitrance of biomass. Due to potential environmental influences on lignin biosynthesis and deposition, studying the consequences of physicochemical changes in field-grown plants without pretreatment is essential to evaluate the performance of lignin-altered plants. In this study, we determined the chemical composition, cellulose crystallinity and the degree of its polymerization, molecular weight of hemicellulose, and cellulose accessibility of cell walls in order to better understand themore » fundamental features of why biomass is recalcitrant to conversion without pretreatment. The most important is to investigate whether traits and features are stable in the dynamics of field environmental effects over multiple years.« less

Cluster-based MOFs with accelerated chemical conversion of CO2 through C-C bond formation.

PubMed

Xiong, Gang; Yu, Bing; Dong, Jie; Shi, Ying; Zhao, Bin; He, Liang-Nian

2017-05-30

Investigations on metal-organic frameworks (MOFs) as direct catalysts have been well documented, but direct catalysis of the chemical conversion of terminal alkynes and CO 2 as chemical feedstock by MOFs into valuable chemical products has never been reported. We report here two cluster-based MOFs I and II assembled from a multinuclear Gd-cluster and Cu-cluster, displaying high thermal and solvent stabilities. I and II as heterogeneous catalysts possess active catalytic centers [Cu 12 I 12 ] and [Cu 3 I 2 ], respectively, exhibiting excellent catalytic performance in the carboxylation reactions of CO 2 with 14 kinds of terminal alkynes under 1 atm and mild conditions. For the first time catalysis of the carboxylation reaction of terminal alkynes with CO 2 by MOF materials without any cocatalyst/additive is reported. This work not only reduces greenhouse gas emission but also provides highly valuable materials, opening a wide space in seeking recoverable catalysts to accelerate the chemical conversion of CO 2 .

Development of life cycle water footprints for the production of fuels and chemicals from algae biomass.

PubMed

Nogueira Junior, Edson; Kumar, Mayank; Pankratz, Stan; Oyedun, Adetoyese Olajire; Kumar, Amit

2018-09-01

This study develops life cycle water footprints for the production of fuels and chemicals via thermochemical conversion of algae biomass. This study is based on two methods of feedstock production - ponds and photobioreactors (PBRs) - and four conversion pathways - fast pyrolysis, hydrothermal liquefaction (HTL), conventional gasification, and hydrothermal gasification (HTG). The results show the high fresh water requirement for algae production and the necessity to recycle harvested water or use alternative water sources. To produce 1 kg of algae through ponds, 1564 L of water are required. When PBRs are used, only 372 L water are required; however, the energy requirements for PBRs are about 30 times higher than for ponds. From a final product perspective, the pathway based on the gasification of algae biomass was the thermochemical conversion method that required the highest amount of water per MJ produced (mainly due to its low hydrogen yield), followed by fast pyrolysis and HTL. On the other hand, HTG has the lowest water footprint, mainly because the large amount of electricity generated as part of the process compensates for the electricity used by the system. Performance in all pathways can be improved through recycling channels. Copyright © 2018 Elsevier Ltd. All rights reserved.

CO2 fixation by anaerobic non-photosynthetic mixotrophy for improved carbon conversion.

PubMed

Jones, Shawn W; Fast, Alan G; Carlson, Ellinor D; Wiedel, Carrissa A; Au, Jennifer; Antoniewicz, Maciek R; Papoutsakis, Eleftherios T; Tracy, Bryan P

2016-09-30

Maximizing the conversion of biogenic carbon feedstocks into chemicals and fuels is essential for fermentation processes as feedstock costs and processing is commonly the greatest operating expense. Unfortunately, for most fermentations, over one-third of sugar carbon is lost to CO 2 due to the decarboxylation of pyruvate to acetyl-CoA and limitations in the reducing power of the bio-feedstock. Here we show that anaerobic, non-photosynthetic mixotrophy, defined as the concurrent utilization of organic (for example, sugars) and inorganic (for example, CO 2 ) substrates in a single organism, can overcome these constraints to increase product yields and reduce overall CO 2 emissions. As a proof-of-concept, Clostridium ljungdahlii was engineered to produce acetone and achieved a mass yield 138% of the previous theoretical maximum using a high cell density continuous fermentation process. In addition, when enough reductant (that is, H 2 ) is provided, the fermentation emits no CO 2 . Finally, we show that mixotrophy is a general trait among acetogens.

Direct enantio-convergent transformation of racemic substrates without racemization or symmetrization

NASA Astrophysics Data System (ADS)

Ito, Hajime; Kunii, Shun; Sawamura, Masaya

2010-11-01

Asymmetric reactions that transform racemic mixtures into enantio-enriched products are in high demand, but classical kinetic resolution produces enantiopure compounds in <50% yield even in an ideal case. Many deracemization processes have thus been developed including dynamic kinetic resolution and dynamic kinetic asymmetric transformation, which can provide enantio-enriched products even after complete conversion of the racemic starting materials. However, these dynamic processes require racemization or symmetrization of the substrates or intermediates. We demonstrate a direct chemical enantio-convergent transformation without a racemization or symmetrization process. Copper(I)-catalysed asymmetric allylic substitution of a racemic allylic ether afforded a single enantiomer of an α-chiral allylboronate with complete conversion and high enantioselectivity (up to 98% enantiomeric excess). One enantiomer of the substrate undergoes an anti-SN2'-type reaction whereas the other enantiomer reacts via a syn-SN2' pathway. The products, which cannot be prepared by dynamic procedures, have been used to construct all-carbon quaternary stereocentres.

Novel insights into the mechanism of the ortho/para spin conversion of hydrogen pairs: implications for catalysis and interstellar water.

PubMed

Limbach, Hans-Heinrich; Buntkowsky, Gerd; Matthes, Jochen; Gründemann, Stefan; Pery, Tal; Walaszek, Bernadeta; Chaudret, Bruno

2006-03-13

The phenomenon of exchange coupling is taken into account in the description of the magnetic nuclear spin conversion between bound ortho- and para-dihydrogen. This conversion occurs without bond breaking, in contrast to the chemical spin conversion. It is shown that the exchange coupling needs to be reduced so that the corresponding exchange barrier can increase and the given magnetic interaction can effectively induce a spin conversion. The implications for related molecules such as water are discussed. For ice, a dipolar magnetic conversion and for liquid water a chemical conversion are predicted to occur within the millisecond timescale. It follows that a separation of water into its spin isomers, as proposed by Tikhonov and Volkov (Science 2002, 296, 2363), is not feasible. Nuclear spin temperatures of water vapor in comets, which are smaller than the gas-phase equilibrium temperatures, are proposed to be diagnostic for the temperature of the ice or the dust surface from which the water was released.

Technician's Perspective on an Ever-Changing Research Environment: Catalytic Conversion of Biomass to Fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thibodeaux, J.; Hensley, J.

2013-01-01

The biomass thermochemical conversion platform at the National Renewable Energy Laboratory (NREL) develops and demonstrates processes for the conversion of biomass to fuels and chemicals including gasification, pyrolysis, syngas clean-up, and catalytic synthesis of alcohol and hydrocarbon fuels. In this talk, I will discuss the challenges of being a technician in this type of research environment, including handling and working with catalytic materials and hazardous chemicals, building systems without being given all of the necessary specifications, pushing the limits of the systems through ever-changing experiments, and achieving two-way communication with engineers and supervisors. I will do this by way ofmore » two examples from recent research. First, I will describe a unique operate-to-failure experiment in the gasification of chicken litter that resulted in the formation of a solid plug in the gasifier, requiring several technicians to chisel the material out. Second, I will compare and contrast bench scale and pilot scale catalyst research, including instances where both are conducted simultaneously from common upstream equipment. By way of example, I hope to illustrate the importance of researchers 1) understanding the technicians' perspective on tasks, 2) openly communicating among all team members, and 3) knowing when to voice opinions. I believe the examples in this talk will highlight the crucial role of a technical staff: skills attained by years of experience to build and operate research and production systems. The talk will also showcase the responsibilities of NREL technicians and highlight some interesting behind-the-scenes work that makes data generation from NREL's thermochemical process development unit possible.« less

Photoelectroreduction of Building-Block Chemicals.

PubMed

Chen, Fengjiao; Cui, Wei; Zhang, Jie; Wang, Yeyun; Zhou, Junhua; Hu, Yongpan; Li, Yanguang; Lee, Shuit-Tong

2017-06-12

Conventional photoelectrochemical cells utilize solar energy to drive the chemical conversion of water or CO 2 into useful chemical fuels. Such processes are confronted with general challenges, including the low intrinsic activities and inconvenient storage and transportation of their gaseous products. A photoelectrochemical approach is proposed to drive the reductive production of industrial building-block chemicals and demonstrate that succinic acid and glyoxylic acid can be readily synthesized on Si nanowire array photocathodes free of any cocatalyst and at room temperature. These photocathodes exhibit a positive onset potential, large saturation photocurrent density, high reaction selectivity, and excellent operation durability. They capitalize on the large photovoltage generated from the semiconductor/electrolyte junction to partially offset the required external bias, and thereby make this photoelectrosynthetic approach significantly more sustainable compared to traditional electrosynthesis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Unconventional processes for food regeneration in space - An overview

NASA Technical Reports Server (NTRS)

Stokes, B. O.; Petersen, G. R.; Schubert, W. W.; Mueller, W. A.

1981-01-01

Alternatives to conventional plant agriculture for the regeneration of food during space missions of extended duration are examined. The options considered, which may be used in combination with conventional agriculture, include the production of food from plant wastes, the chemical synthesis of food from carbon dioxide and other simple molecules or the substitution of edible chemicals, and the use of microrganisms for food and oxygen regeneration, with suitable processing. A comparison of solar energy conversion efficiencies is presented for nonphotosynthetic bacteria grown on hydrogen and algal systems photosynthetically, and it is shown that hydrogen bacteria are potentially more attractive than photosynthetic algae using artificial light. Weight-volume requirements for the conventional plant, algae and hydrogen bacteria systems are also compared to demonstrate the advantages of microbial systems.

ESM of ionic and electrochemical phenomena on the nanoscale

DOE PAGES

Kalinin, Sergei V.; Kumar, Amit; Balke, Nina; ...

2011-01-01

Operation of energy storage and conversion devices is ultimately controlled by series of intertwined ionic and electronic transport processes and electrochemical reactions at surfaces and interfaces, strongly mediated by strain and mechanical processes. In a typical fuel cell, these include chemical species transport in porous cathode and anode materials, gas-solid electrochemical reactions at grains and triple-phase boundaries (TPBs), ionic and electronic flows in multicomponent electrodes, and chemical and electronic potential drops at internal interfaces in electrodes and electrolytes. Furthermore, all these phenomena are sensitively affected by the microstructure of materials from device level to the atomic scales. Similar spectrum ofmore » length scales and phenomena underpin operation of other energy systems including primary and secondary batteries, as well as hybrid systems such flow and metal-air/water batteries.« less

Hydrothermal pretreatment of several lignocellulosic mixtures containing wheat straw and two hardwood residues available in Southern Europe.

PubMed

Silva-Fernandes, Talita; Duarte, Luís Chorão; Carvalheiro, Florbela; Loureiro-Dias, Maria Conceição; Fonseca, César; Gírio, Francisco

2015-05-01

This work studied the processing of biomass mixtures containing three lignocellulosic materials largely available in Southern Europe, eucalyptus residues (ER), wheat straw (WS) and olive tree pruning (OP). The mixtures were chemically characterized, and their pretreatment, by autohydrolysis, evaluated within a severity factor (logR0) ranging from 1.73 up to 4.24. A simple modeling strategy was used to optimize the autohydrolysis conditions based on the chemical characterization of the liquid fraction. The solid fraction was characterized to quantify the polysaccharide and lignin content. The pretreatment conditions for maximal saccharides recovery in the liquid fraction were at a severity range (logR0) of 3.65-3.72, independently of the mixture tested, which suggests that autohydrolysis can effectively process mixtures of lignocellulosic materials for further biochemical conversion processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Chemical and biotechnological processing of collagen-containing raw materials into functional components of feed suitable for production of high-quality meat from farm animals

NASA Astrophysics Data System (ADS)

Baburina, M. I.; Ivankin, A. N.; Stanovova, I. A.

2017-09-01

The process of chemical biotechnological processing of collagen-containing raw materials into functional components of feeds for effective pig rearing was studied. Protein components of feeds were obtained as a result of hydrolysis in the presence of lactic acid of the animal collagen from secondary raw materials, which comprised subcutaneous collagen (cuticle), skin and veined mass with tendons from cattle. For comparison, a method is described for preparing protein components of feeds by cultivating Lactobacillus plantarum. Analysis of the kinetic data of the conversion of a high-molecular collagen protein to an aminolyte polypeptide mixture showed the advantage of microbiological synthesis in obtaining a protein for feeds. Feed formulations have been developed to include the components obtained, and which result in high quality pork suitable for the production of quality meat products.

Energy-efficient biomass processing with pulsed electric fields for bioeconomy and sustainable development.

PubMed

Golberg, Alexander; Sack, Martin; Teissie, Justin; Pataro, Gianpiero; Pliquett, Uwe; Saulis, Gintautas; Stefan, Töpfl; Miklavcic, Damijan; Vorobiev, Eugene; Frey, Wolfgang

2016-01-01

Fossil resources-free sustainable development can be achieved through a transition to bioeconomy, an economy based on sustainable biomass-derived food, feed, chemicals, materials, and fuels. However, the transition to bioeconomy requires development of new energy-efficient technologies and processes to manipulate biomass feed stocks and their conversion into useful products, a collective term for which is biorefinery. One of the technological platforms that will enable various pathways of biomass conversion is based on pulsed electric fields applications (PEF). Energy efficiency of PEF treatment is achieved by specific increase of cell membrane permeability, a phenomenon known as membrane electroporation. Here, we review the opportunities that PEF and electroporation provide for the development of sustainable biorefineries. We describe the use of PEF treatment in biomass engineering, drying, deconstruction, extraction of phytochemicals, improvement of fermentations, and biogas production. These applications show the potential of PEF and consequent membrane electroporation to enable the bioeconomy and sustainable development.

Plasma chemical conversion of sulphur hexafluoride initiated by a pulsed electron beam

NASA Astrophysics Data System (ADS)

Kholodnaya, Galina; Sazonov, Roman; Ponomarev, Denis; Guzeeva, Tatiana

2017-01-01

This paper presents the results of the experimental investigation of plasma chemical conversion of sulphur hexafluoride initiated by a pulsed electron beam (TEA-500 pulsed electron accelerator) with the following characteristics: 400-450 keV electron energy, 60 ns pulse duration, up to 200 J pulse energy, and 5 cm beam diameter. Experiments were conducted on the effect of the pulsed electron beam on SF6 and on mixtures of SF6 with O2, Ar, or N2. For the mixture of SF6 and oxygen, the results indicated chemical reactions involving the formation of a number of products of which one is sulphur, confirming the Wray - Fluorescence Analysis. The plasma chemical conversion of SF6 initiated by the pulsed electron beam was not detected when SF6 was mixed with Ar or N2, suggesting a possible mechanism for the reaction of SF6 in the presence of O2.

Analysis of digester design concepts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ashare, E.; Wilson, E. H.

1979-01-29

Engineering economic analyses were performed on various digester design concepts to determine the relative performance for various biomass feedstocks. A comprehensive literature survey describing the state-of-the-art of the various digestion designs is included. The digester designs included in the analyses are CSTR, plug flow, batch, CSTR in series, multi-stage digestion and biomethanation. Other process options investigated included pretreatment processes such as shredding, degritting, and chemical pretreatment, and post-digestion processes, such as dewatering and gas purification. The biomass sources considered include feedlot manure, rice straw, and bagasse. The results of the analysis indicate that the most economical (on a unit gasmore » cost basis) digester design concept is the plug flow reactor. This conclusion results from this system providing a high gas production rate combined with a low capital hole-in-the-ground digester design concept. The costs determined in this analysis do not include any credits or penalties for feedstock or by-products, but present the costs only for conversion of biomass to methane. The batch land-fill type digester design was shown to have a unit gas cost comparable to that for a conventional stirred tank digester, with the potential of reducing the cost if a land-fill site were available for a lower cost per unit volume. The use of chemical pretreatment resulted in a higher unit gas cost, primarily due to the cost of pretreatment chemical. A sensitivity analysis indicated that the use of chemical pretreatment could improve the economics provided a process could be developed which utilized either less pretreatment chemical or a less costly chemical. The use of other process options resulted in higher unit gas costs. These options should only be used when necessary for proper process performance, or to result in production of a valuable by-product.« less

Titanium dioxide nanotube membranes for solar energy conversion: effect of deep and shallow dopants.

PubMed

Ding, Yuchen; Nagpal, Prashant

2017-04-12

Nanostructured titanium dioxide (TiO 2 ) has been intensively investigated as a material of choice for solar energy conversion in photocatalytic, photoelectrochemical, photovoltaic, and other photosensitized devices for converting light into chemical feedstocks or electricity. Towards management of light absorption in TiO 2 , while the nanotubular structure improves light absorption and simultaneous charge transfer to mitigate problems due to the indirect bandgap of the semiconductor, typically dopants are used to improve light absorption of incident solar irradiation in the wide bandgap of TiO 2 . While these dopants can be critical to the success of these solar energy conversion devices, their effect on photophysical and photoelectrochemical properties and detailed photokinetics are relatively under-studied. Here, we show the effect of deep and shallow metal dopants on the kinetics of photogenerated charged carriers in TiO 2 and the resulting effect on photocatalytic and photoelectrochemical processes using these nanotube membranes. We performed a detailed optical, electronic, voltammetry and electrochemical impedance study to understand the effect of shallow and deep metal dopants (using undoped and niobium- and copper-doped TiO 2 nanotubes) on light absorption, charge transport and charge transfer processes. Using wireless photocatalytic methylene blue degradation and carbon dioxide reduction, and wired photoelectrochemical device measurements, we elucidate the effect of different dopants on solar-to-fuel conversion efficiency and simultaneously describe the photokinetics using a model, to help design better energy conversion devices.

Evaluating Indicators and Life Cycle Inventories for Processes in Early Stages of Technical Readiness

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Eric C; Smith, Raymond; Ruiz-Mercado, Gerardo

This presentation examines different methods for analyzing manufacturing processes in the early stages of technical readiness. Before developers know much detail about their processes, it is valuable to apply various assessments to evaluate their performance. One type of assessment evaluates performance indicators to describe how closely processes approach desirable objectives. Another type of assessment determines the life cycle inventories (LCI) of inputs and outputs for processes, where for a functional unit of product, the user evaluates the resources used and the releases to the environment. These results can be compared to similar processes or combined with the LCI of othermore » processes to examine up-and down-stream chemicals. The inventory also provides a listing of the up-stream chemicals, which permits study of the whole life cycle. Performance indicators are evaluated in this presentation with the U.S. Environmental Protection Agency's GREENSCOPE (Gauging Reaction Effectiveness for ENvironmental Sustainability with a multi-Objective Process Evaluator) methodology, which evaluates processes in four areas: Environment, Energy, Economics, and Efficiency. The method develops relative scores for indicators that allow comparisons across various technologies. In this contribution, two conversion pathways for producing cellulosic ethanol from biomass, via thermochemical and biochemical routes, are studied. The information developed from the indicators and LCI can be used to inform the process design and the potential life cycle effects of up- and down-stream chemicals.« less

Efficient electrochemical CO 2 conversion powered by renewable energy

DOE PAGES

Kauffman, Douglas R.; Thakkar, Jay; Siva, Rajan; ...

2015-06-29

Here, the catalytic conversion of CO 2 into industrially relevant chemicals is one strategy for mitigating greenhouse gas emissions. Along these lines, electrochemical CO 2 conversion technologies are attractive because they can operate with high reaction rates at ambient conditions. However, electrochemical systems require electricity, and CO 2 conversion processes must integrate with carbon-free, renewable-energy sources to be viable on larger scales. We utilize Au 25 nanoclusters as renewably powered CO 2 conversion electrocatalysts with CO 2 → CO reaction rates between 400 and 800 L of CO 2 per gram of catalytic metal per hour and product selectivities betweenmore » 80 and 95%. These performance metrics correspond to conversion rates approaching 0.8–1.6 kg of CO 2 per gram of catalytic metal per hour. We also present data showing CO 2 conversion rates and product selectivity strongly depend on catalyst loading. Optimized systems demonstrate stable operation and reaction turnover numbers (TONs) approaching 6 × 10 6 mol CO 2 molcatalyst–1 during a multiday (36 hours total hours) CO 2electrolysis experiment containing multiple start/stop cycles. TONs between 1 × 10 6 and 4 × 10 6 molCO 2 molcatalyst–1 were obtained when our system was powered by consumer-grade renewable-energy sources. Daytime photovoltaic-powered CO 2 conversion was demonstrated for 12 h and we mimicked low-light or nighttime operation for 24 h with a solar-rechargeable battery. This proof-of-principle study provides some of the initial performance data necessary for assessing the scalability and technical viability of electrochemical CO 2 conversion technologies. Specifically, we show the following: (1) all electrochemical CO 2 conversion systems will produce a net increase in CO 2 emissions if they do not integrate with renewable-energy sources, (2) catalyst loading vs activity trends can be used to tune process rates and product distributions, and (3) state-of-the-art renewable-energy technologies are sufficient to power larger-scale, tonne per day CO 2 conversion systems.« less

Conversion of the trace elements Zn, Cd, and Pb in the combustion of near-Moscow coals

DOE Office of Scientific and Technical Information (OSTI.GOV)

E.V. Samuilov; L.N. Lebedeva; L.S. Pokrovskaya

A model for the conversion of trace elements in the combustion of near-Moscow coals based on a complex approach combining the capabilities of geochemistry, chemical thermodynamics, phase analysis, and chemical kinetics is proposed. The conversion of the trace elements Zn, Cd, and Pb as the constituents of near-Moscow coal in the flow of coal combustion products along the line of the P-59 boiler at the Ryazanskaya Thermal Power Plant was calculated. Experimental data were used in the development of the model and in calculations.

Low emittance chromated chemical conversion coatings for spacecraft thermal control in low earth orbit

NASA Astrophysics Data System (ADS)

LeVesque, R. J.; DeJesus, R. R.; Jones, C. A.; Babel, H. W.

1996-03-01

Low emittance coatings were required on the inner side of micro-meteoroid shielding and other structures to minimize heat transfer from the sun illuminated side to the underlying structure. A program was undertaken to evaluate conversion coatings for long term use in space. The conversion coatings evaluated were Alodine 1200 with three different bath chemistries, Iridite 14-2, and Alodine 600. Although the primary emphasis was on evaluating how processing conditions influenced the infrared emittance, corrosion resistance and electrical bonding characteristics were also evaluated. All of the conversion coatings were able to provide the target emittance value of less than 0.10, although baths with ferricyanide accelerators required shorter immersion times than typical of standard shop practices. The balance between emittance, corrosion resistance, and electrical bonding were defined. Space environmental stability tests were conducted on conversion coated 2219 and 7075 aluminum. The emittance and the electrical bonding characteristics were not affected by the space exposure even though the coating dehydrated and mud cracking is evident under a microscope. The dehydration resulted in a loss of corrosion resistance which is a consideration for hardware returned to Earth. It was concluded that conversion coatings are acceptable thermal control coatings for long life spacecraft although additional work is recommended for solar exposed surfaces.

Study of parameters affecting the conversion in a plug flow reactor for reactions of the type 2A→B

NASA Astrophysics Data System (ADS)

Beltran-Prieto, Juan Carlos; Long, Nguyen Huynh Bach Son

2018-04-01

Modeling of chemical reactors is an important tool to quantify reagent conversion, product yield and selectivity towards a specific compound and to describe the behavior of the system. Proposal of differential equations describing the mass and energy balance are among the most important steps required during the modeling process as they play a special role in the design and operation of the reactor. Parameters governing transfer of heat and mass have a strong relevance in the rate of the reaction. Understanding this information is important for the selection of reactor and operating regime. In this paper we studied the irreversible gas-phase reaction 2A→B. We model the conversion that can be achieved as function of the reactor volume and feeding temperature. Additionally, we discuss the effect of activation energy and the heat of reaction on the conversion achieved in the tubular reactor. Furthermore, we considered that dimerization occurs instantaneously in the catalytic surface to develop equations for the determination of rate of reaction per unit area of three different catalytic surface shapes. This data can be combined with information about the global rate of conversion in the reactor to improve regent conversion and yield of product.

Systems Biology of Industrial Microorganisms

NASA Astrophysics Data System (ADS)

Papini, Marta; Salazar, Margarita; Nielsen, Jens

The field of industrial biotechnology is expanding rapidly as the chemical industry is looking towards more sustainable production of chemicals that can be used as fuels or building blocks for production of solvents and materials. In connection with the development of sustainable bioprocesses, it is a major challenge to design and develop efficient cell factories that can ensure cost efficient conversion of the raw material into the chemical of interest. This is achieved through metabolic engineering, where the metabolism of the cell factory is engineered such that there is an efficient conversion of sugars, the typical raw materials in the fermentation industry, into the desired product. However, engineering of cellular metabolism is often challenging due to the complex regulation that has evolved in connection with adaptation of the different microorganisms to their ecological niches. In order to map these regulatory structures and further de-regulate them, as well as identify ingenious metabolic engineering strategies that full-fill mass balance constraints, tools from systems biology can be applied. This involves both high-throughput analysis tools like transcriptome, proteome and metabolome analysis, as well as the use of mathematical modeling to simulate the phenotypes resulting from the different metabolic engineering strategies. It is in fact expected that systems biology may substantially improve the process of cell factory development, and we therefore propose the term Industrial Systems Biology for how systems biology will enhance the development of industrial biotechnology for sustainable chemical production.

Systems biology of industrial microorganisms.

PubMed

Papini, Marta; Salazar, Margarita; Nielsen, Jens

2010-01-01

The field of industrial biotechnology is expanding rapidly as the chemical industry is looking towards more sustainable production of chemicals that can be used as fuels or building blocks for production of solvents and materials. In connection with the development of sustainable bioprocesses, it is a major challenge to design and develop efficient cell factories that can ensure cost efficient conversion of the raw material into the chemical of interest. This is achieved through metabolic engineering, where the metabolism of the cell factory is engineered such that there is an efficient conversion of sugars, the typical raw materials in the fermentation industry, into the desired product. However, engineering of cellular metabolism is often challenging due to the complex regulation that has evolved in connection with adaptation of the different microorganisms to their ecological niches. In order to map these regulatory structures and further de-regulate them, as well as identify ingenious metabolic engineering strategies that full-fill mass balance constraints, tools from systems biology can be applied. This involves both high-throughput analysis tools like transcriptome, proteome and metabolome analysis, as well as the use of mathematical modeling to simulate the phenotypes resulting from the different metabolic engineering strategies. It is in fact expected that systems biology may substantially improve the process of cell factory development, and we therefore propose the term Industrial Systems Biology for how systems biology will enhance the development of industrial biotechnology for sustainable chemical production.

Minimizing the formation of coke and methane on Co nanoparticles in steam reforming of biomass-derived oxygenates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Junming; Mei, Donghai; Karim, Ayman M.

2013-06-01

Fundamental understanding and control of chemical transformations are essential to the development of technically feasible and economically viable catalytic processes for efficient conversion of biomass to fuels and chemicals. Using an integrated experimental and theoretical approach, we report high hydrogen selectivity and catalyst durability of acetone steam reforming (ASR) on inert carbon supported Co nanoparticles. The observed catalytic performance is further elucidated on the basis of comprehensive first-principles calculations. Instead of being considered as an undesired intermediate prone for catalyst deactivation during bioethanol steam reforming (ESR), acetone is suggested as a key and desired intermediate in proposed two-stage ESR processmore » that leads to high hydrogen selectivity and low methane formation on Co-based catalysts. The significance of the present work also sheds a light on controlling the chemical transformations of key intermediates in biomass conversion such as ketones. We gratefully acknowledge the financial support from U. S. Department of Energy (DOE), Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences, and the Laboratory directed research and development (LDRD) project of Pacific Northwest National Laboratory (PNNL). Computing time was granted by the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL). The EMSL is a U.S. DOE national scientific user facility located at PNNL, and sponsored by the U.S. DOE’s Office of Biological and Environmental Research.« less

Cogeneration Technology Alternatives Study (CTAS). Volume 1: Summary report

NASA Technical Reports Server (NTRS)

Gerlaugh, H. E.; Hall, E. W.; Brown, D. H.; Priestley, R. R.; Knightly, W. F.

1980-01-01

Large savings can be made in industry by cogenerating electric power and process heat in single energy conversion systems rather than separately in utility plants and in process boilers. About fifty industrial processes from the largest energy consuming sectors were used as a basis for matching a similar number of energy conversion systems that are considered as candidates which can be made available by the 1985 to 2000 time period. The sectors considered included food, textiles, lumber, paper, chemicals, petroleum, glass, and primary metals. The energy conversion systems included steam and gas turbines, diesels, thermionics, stirling, closed-cycle and steam injected gas turbines, and fuel cells. Fuels considered were coal, both coal and petroleum-based residual and distillate liquid fuels, and low Btu gas obtained through the on-site gasification of coal. An attempt was made to use consistent assumptions and a consistent set of ground rules for determining performance and cost in individual plants and on a national level. It was found that: (1) atmospheric and pressurized fluidized bed steam turbine systems were the most attractive of the direct coal-fired systems; and (2) open-cycle gas turbines with heat recovery steam generators and combined-cycles with NO(x) emission reduction and moderately increased firing temperatures were the most attractive of the coal-derived liquid-fired systems.

15 CFR 710.1 - Definitions of terms used in the Chemical Weapons Convention Regulations (CWCR).

Code of Federal Regulations, 2010 CFR

2010-01-01

... chemical means its conversion into another chemical via a chemical reaction. Unreacted material must be... formed through chemical reaction that is subsequently reacted to form another chemical. ITAR. Means the... formation of a chemical through chemical reaction, including biochemical or biologically mediated reaction...

Control of laser-ablated aluminum surface wettability to superhydrophobic or superhydrophilic through simple heat treatment or water boiling post-processing

NASA Astrophysics Data System (ADS)

Ngo, Chi-Vinh; Chun, Doo-Man

2018-03-01

Recently, controlling the wettability of a metallic surface so that it is either superhydrophobic or superhydrophilic has become important for many applications. However, conventional techniques require long fabrication times or involve toxic chemicals. Herein, through a combination of pulse laser ablation and simple post-processing, the surface of aluminum was controlled to either superhydrophobic or superhydrophilic in a short time of only a few hours. In this study, grid patterns were first fabricated on aluminum using a nanosecond pulsed laser, and then additional post-processing without any chemicals was used. Under heat treatment, the surface became superhydrophobic with a contact angle (CA) greater than 150° and a sliding angle (SA) lower than 10°. Conversely, when immersed in boiling water, the surface became superhydrophilic with a low contact angle. The mechanism for wettability change was also explained. The surfaces, obtained in a short time with environmentally friendly fabrication and without the use of toxic chemicals, could potentially be applied in various industry and manufacturing applications such as self-cleaning, anti-icing, and biomedical devices.

Sulfur amino acids and alanine on pyrite (100) by X-ray photoemission spectroscopy: Surface or molecular role?

NASA Astrophysics Data System (ADS)

Sanchez-Arenillas, M.; Galvez-Martinez, S.; Mateo-Marti, E.

2017-08-01

This paper describes the first successful adsorption of the cysteine, cystine, methionine and alanine amino acids on the pyrite (100) surface under ultra-high vacuum conditions with crucial chemical adsorption parameters driving the process. We have demonstrated by X-ray photoemission spectroscopy (XPS) that the surface pretreatment annealing process on pyrite surfaces is a critical parameter driving surface reactivity. The presence of enriched monosulfide species on the pyrite (100) surface favours the amino acid NH2 chemical form, whereas a longer annealing surface pretreatment of over 3 h repairs the sulfur vacancies in the pyrite, enriching disulfide species on the pyrite surface, which promotes NH3+ adsorption due to the sulfur vacancies in the pyrite being replaced by sulfur atom dimers (S22-) on the surface. Furthermore, even if the surface chemistry (monosulfide or disulfide species enrichment) is the main factor promoting a partial conversion from NH2 to NH3+ species, the unique chemical structure of each amino acid provides a particular fingerprint in the process.

High-Performance Ultrathin Organic-Inorganic Hybrid Silicon Solar Cells via Solution-Processed Interface Modification.

PubMed

Zhang, Jie; Zhang, Yinan; Song, Tao; Shen, Xinlei; Yu, Xuegong; Lee, Shuit-Tong; Sun, Baoquan; Jia, Baohua

2017-07-05

Organic-inorganic hybrid solar cells based on n-type crystalline silicon and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) exhibited promising efficiency along with a low-cost fabrication process. In this work, ultrathin flexible silicon substrates, with a thickness as low as tens of micrometers, were employed to fabricate hybrid solar cells to reduce the use of silicon materials. To improve the light-trapping ability, nanostructures were built on the thin silicon substrates by a metal-assisted chemical etching method (MACE). However, nanostructured silicon resulted in a large amount of surface-defect states, causing detrimental charge recombination. Here, the surface was smoothed by solution-processed chemical treatment to reduce the surface/volume ratio of nanostructured silicon. Surface-charge recombination was dramatically suppressed after surface modification with a chemical, associated with improved minority charge-carrier lifetime. As a result, a power conversion efficiency of 9.1% was achieved in the flexible hybrid silicon solar cells, with a substrate thickness as low as ∼14 μm, indicating that interface engineering was essential to improve the hybrid junction quality and photovoltaic characteristics of the hybrid devices.

Chemical Conversions of Biomass-Derived Platform Chemicals over Copper-Silica Nanocomposite Catalysts.

PubMed

Upare, Pravin P; Hwang, Young Kyu; Lee, Jong-Min; Hwang, Dong Won; Chang, Jong-San

2015-07-20

Biomass and biomass-derived carbohydrates have a high extent of functionality, unlike petroleum, which has limited functionality. In biorefinery applications, the development of methods to control the extent of functionality in final products intended for use as fuels and chemicals is a challenge. In the chemical industry, heterogeneous catalysis is an important tool for the defunctionalization of functionalized feedstocks and biomass-derived platform chemicals to produce value-added chemicals. Herein, we review the recent progress in this field, mainly of vapor phase chemical conversion of biomass-derived C4 -C6 carboxylic acids and esters using copper-silica nanocomposite catalysts. We also demonstrate that these nanocomposite catalysts very efficiently convert biomass-derived platform chemicals into cyclic compounds, such as lactones and hydrofurans, with high selectivities and yields. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rainwater as a chemical agent of geologic processes; a review

USGS Publications Warehouse

Carroll, Dorothy

1962-01-01

Chemical analyses of the rainwater collected at several localities are given to show the variations of the principal constitutents. In rock weathering and soil-forming processes, the chemical composition of rainwater has an important effect which has been evaluated for only a few arid areas. In humid regions the important amounts of calcium, magnesium, sodium, and potassium added yearly by rain may be expected to influence the composition of the soil water and thereby the cations in the exchange positions of soil clay minerals. The acquisition of cations by clay minerals may slow down chemical weathering. The stability of soil clay minerals is influenced by the constant accession of cations from rainwater. Conversely, the clay minerals modify the amounts and kinds of cations that are leached out by drainage waters. The stability of micaceous minerals in soils may be partly due to accessions of K +1 ions from rainwater. The pH of rainwater in any area varies considerably and seems to form a seasonal and regional pattern. The recorded pH values range from 3.0 to 9.8.

Chemical coupling between acid gases and water-soluble inorganic ions in size-segregated aerosols during Arabian Dust in Beirut

NASA Astrophysics Data System (ADS)

Saliba, Najat; Dada, Lubna; Baalbaki, Rima

2015-04-01

In the proximity of the Eastern Mediterranean region, the combination of two large desert areas; Arabian and African, with heavy oil industry and high insolation during summer delineate a unique location of atmospheric processes in the region. Once emitted, dust particles can be transported over long distances and/or remain suspended in the atmosphere for several days. The so-called remnant dust episodes in Beirut originate from both African and Arabian deserts. In this study, the gas and particle transformations and gas-to-particle conversion during Arabian-dust (Ar-D) events are assessed. The increase in primary and secondary gas concentrations during Ar-D days is ascribed to three contributing factors; (i) the regional-long-range transport (LRT), (ii) the drop in the average solar radiation leading to a slow primary-to-secondary conversion and secondary gas photo-degradation, and (iii) the enhancement of the recirculation and accumulation of the main pollutants during dusty days. In parallel, a respective mass increase by 137, 149 and 13% in the coarse (CPM), accumulation (ACC) and ultrafine (UF) fractions was measured and an increase in particle volume distribution was mostly noticed for particles ranging in sizes between 2.25 and 5 μm. This lead to major changes in the inorganic chemical composition of all particle sizes. In particular, the enhanced presence of several types of nitrate and sulfate salts in the accumulation mode confirms that remnant dust episodes offer a favorable environment for gas-to-particle conversion and particle chemical transformations and growth.

Electrocatalytic processing of renewable biomass-derived compounds for production of chemicals, fuels and electricity

NASA Astrophysics Data System (ADS)

Xin, Le

The dual problems of sustaining the fast growth of human society and preserving the environment for future generations urge us to shift our focus from exploiting fossil oils to researching and developing more affordable, reliable and clean energy sources. Human beings had a long history that depended on meeting our energy demands with plant biomass, and the modern biorefinery technologies realize the effective conversion of biomass to production of transportation fuels, bulk and fine chemicals so to alleviate our reliance on fossil fuel resources of declining supply. With the aim of replacing as much non-renewable carbon from fossil oils with renewable carbon from biomass as possible, innovative R&D activities must strive to enhance the current biorefinery process and secure our energy future. Much of my Ph.D. research effort is centered on the study of electrocatalytic conversion of biomass-derived compounds to produce value-added chemicals, biofuels and electrical energy on model electrocatalysts in AEM/PEM-based continuous flow electrolysis cell and fuel cell reactors. High electricity generation performance was obtained when glycerol or crude glycerol was employed as fuels in AEMFCs. The study on selective electrocatalytic oxidation of glycerol shows an electrode potential-regulated product distribution where tartronate and mesoxalate can be selectively produced with electrode potential switch. This finding then led to the development of AEMFCs with selective production of valuable tartronate or mesoxalate with high selectivity and yield and cogeneration of electricity. Reaction mechanisms of electrocatalytic oxidation of ethylene glycol and 1,2-propanediol were further elucidated by means of an on-line sample collection technique and DFT modeling. Besides electro-oxidation of biorenewable alcohols to chemicals and electricity, electrocatalytic reduction of keto acids (e.g. levulinic acid) was also studied for upgrading biomass-based feedstock to biofuels while achieving renewable electricity storage. Meanwhile, ORR that is often coupled in AEMFCs on the cathode was investigated on non-PGM electrocatalyst with comparable activity to commercial Pt/C. The electro-biorefinery process could be coupled with traditional biorefinery operation and will play a significant role in our energy and chemical landscape.

Gasification Characteristics of Coal/Biomass Mixed Fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitchell, Reginald

2014-09-01

A research project was undertaken that had the overall objective of developing the models needed to accurately predict conversion rates of coal/biomass mixtures to synthesis gas under conditions relevant to a commercially-available coal gasification system configured to co-produce electric power as well as chemicals and liquid fuels. In our efforts to accomplish this goal, experiments were performed in an entrained flow reactor in order to produce coal and biomass chars at high heating rates and temperatures, typical of the heating rates and temperatures fuel particles experience in real systems. Mixed chars derived from coal/biomass mixtures containing up to 50% biomassmore » and the chars of the pure coal and biomass components were subjected to a matrix of reactivity tests in a pressurized thermogravimetric analyzer (TGA) in order to obtain data on mass loss rates as functions of gas temperature, pressure and composition as well as to obtain information on the variations in mass specific surface area during char conversion under kinetically-limited conditions. The experimental data were used as targets when determining the unknown parameters in the chemical reactivity and specific surface area models developed. These parameters included rate coefficients for the reactions in the reaction mechanism, enthalpies of formation and absolute entropies of adsorbed species formed on the carbonaceous surfaces, and pore structure coefficients in the model used to describe how the mass specific surface area of the char varies with conversion. So that the reactivity models can be used at high temperatures when mass transport processes impact char conversion rates, Thiele modulus – effectiveness factor relations were also derived for the reaction mechanisms developed. In addition, the reactivity model and a mode of conversion model were combined in a char-particle gasification model that includes the effects of chemical reaction and diffusion of reactive gases through particle pores and energy exchange between the particle and its environment. This char-particle gasification model is capable of predicting the average mass loss rates, sizes, apparent densities, specific surface areas, and temperatures of the char particles produced when co-firing coal and biomass to the type environments established in entrained flow gasifiers operating at high temperatures and elevated pressures.« less

Modeling and Design Optimization of Multifunctional Membrane Reactors for Direct Methane Aromatization

PubMed Central

Fouty, Nicholas J.; Carrasco, Juan C.; Lima, Fernando V.

2017-01-01

Due to the recent increase of natural gas production in the U.S., utilizing natural gas for higher-value chemicals has become imperative. Direct methane aromatization (DMA) is a promising process used to convert methane to benzene, but it is limited by low conversion of methane and rapid catalyst deactivation by coking. Past work has shown that membrane separation of the hydrogen produced in the DMA reactions can dramatically increase the methane conversion by shifting the equilibrium toward the products, but it also increases coke production. Oxygen introduction into the system has been shown to inhibit this coke production while not inhibiting the benzene production. This paper introduces a novel mathematical model and design to employ both methods in a multifunctional membrane reactor to push the DMA process into further viability. Multifunctional membrane reactors, in this case, are reactors where two different separations occur using two differently selective membranes, on which no systems studies have been found. The proposed multifunctional membrane design incorporates a hydrogen-selective membrane on the outer wall of the reaction zone, and an inner tube filled with airflow surrounded by an oxygen-selective membrane in the middle of the reactor. The design is shown to increase conversion via hydrogen removal by around 100%, and decrease coke production via oxygen addition by 10% when compared to a tubular reactor without any membranes. Optimization studies are performed to determine the best reactor design based on methane conversion, along with coke and benzene production. The obtained optimal design considers a small reactor (length = 25 cm, diameter of reaction tube = 0.7 cm) to subvert coke production and consumption of the product benzene as well as a high permeance (0.01 mol/s·m2·atm1/4) through the hydrogen-permeable membrane. This modeling and design approach sets the stage for guiding further development of multifunctional membrane reactor models and designs for natural gas utilization and other chemical reaction systems. PMID:28850068

Innovative Chemical Process for Recycling Thermosets Cured with Recyclamines® by Converting Bio-Epoxy Composites in Reusable Thermoplastic—An LCA Study

PubMed Central

Banatao, Diosdado R.; Pastine, Stefan J.

2018-01-01

An innovative recycling process for thermoset polymer composites developed by Connora Technologies (Hayward, CA, USA) was studied. The process efficacy has already been tested, and it is currently working at the plant level. The main aspect investigated in the present paper was the environmental impact by means of the Life Cycle Assessment (LCA) method. Because of the need to recycle and recover materials at their end of life, the Connora process creates a great innovation in the market of epoxy composites, as they are notoriously not recyclable. Connora Technologies developed a relatively gentle chemical recycling process that induces the conversion of thermosets into thermoplastics. The LCA demonstrated that low environmental burdens are associated with the process itself and, furthermore, impacts are avoided due to the recovery of the epoxy-composite constituents (fibres and matrix). A carbon fibre (CF) epoxy-composite panel was produced through Vacuum Resin Transfer Moulding (VRTM) and afterwards treated using the Connora recycling process. The LCA results of both the production and the recycling phases are reported. PMID:29495571

Conversion of radioactive ferrocyanide compounds to immobile glasses

DOEpatents

Schulz, Wallace W.; Dressen, A. Louise

1977-04-26

Complex radioactive ferrocyanide compounds result from the scavenging of cesium from waste products produced in the chemical reprocessing of nuclear fuel. These ferrocyanides, in accordance with this process, are converted to an immobile glass, resistant to leaching by water, by fusion together with sodium carbonate and a mixture of (a) basalt and boron trioxide (B.sub.2 O.sub.3) or (b) silica (SiO.sub.2) and lime (CaO).

Obtaining value prior to pulping with diethyl oxalate and oxalic acid

Treesearch

W.R. Kenealy; E. Horn; C.J. Houtman; J. Laplaza; T.W. Jeffries

2007-01-01

Pulp and paper are converted to paper products with yields of paper dependent on the wood and the process used. Even with high yield pulps there are conversion losses and with chemical pulps the yields approach 50%. The portions of the wood that do not provide product are either combusted to generate power and steam or incur a cost in waste water treatment. Value prior...

Process for solvent refining of coal using a denitrogenated and dephenolated solvent

DOEpatents

Garg, Diwakar; Givens, Edwin N.; Schweighardt, Frank K.

1984-01-01

A process is disclosed for the solvent refining of non-anthracitic coal at elevated temperatures and pressure in a hydrogen atmosphere using a hydrocarbon solvent which before being recycled in the solvent refining process is subjected to chemical treatment to extract substantially all nitrogenous and phenolic constituents from the solvent so as to improve the conversion of coal and the production of oil in the solvent refining process. The solvent refining process can be either thermal or catalytic. The extraction of nitrogenous compounds can be performed by acid contact such as hydrogen chloride or fluoride treatment, while phenolic extraction can be performed by caustic contact or contact with a mixture of silica and alumina.

Linear constraint relations in biochemical reaction systems: I. Classification of the calculability and the balanceability of conversion rates.

PubMed

van der Heijden, R T; Heijnen, J J; Hellinga, C; Romein, B; Luyben, K C

1994-01-05

Measurements provide the basis for process monitoring and control as well as for model development and validation. Systematic approaches to increase the accuracy and credibility of the empirical data set are therefore of great value. In (bio)chemical conversions, linear conservation relations such as the balance equations for charge, enthalpy, and/or chemical elements, can be employed to relate conversion rates. In a pactical situation, some of these rates will be measured (in effect, be calculated directly from primary measurements of, e.g., concentrations and flow rates), as others can or cannot be calculated from the measured ones. When certain measured rates can also be calculated from other measured rates, the set of equations, the accuracy and credibility of the measured rates can indeed be improved by, respectively, balancing and gross error diagnosis. The balanced conversion rates are more accurate, and form a consistent set of data, which is more suitable for further application (e.g., to calculate nonmeasured rates) than the raw measurements. Such an approach has drawn attention in previous studies. The current study deals mainly with the problem of mathematically classifying the conversion rates into balanceable and calculable rates, given the subset of measured rates. The significance of this problem is illustrated with some examples. It is shown that a simple matrix equation can be derived that contains the vector of measured conversion rates and the redundancy matrix R. Matrix R plays a predominant role in the classification problem. In supplementary articles, significance of the redundancy matrix R for an improved gross error diagnosis approach will be shown. In addition, efficient equations have been derived to calculate the balanceable and/or calculable rates. The method is completely based on matrix algebra (principally different from the graph-theoretical approach), and it is easily implemented into a computer program. (c) 1994 John Wiley & Sons, Inc.

Air Permitting Implications of a Biorefinery Producing Raw Bio-Oil in Comparison with Producing Gasoline and Diesel Blendstocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhatt, Arpit H; Zhang, Yi Min

A biorefinery, considered a chemical process plant under the Clean Air Act permitting program, could be classified as a major or minor source based on the size of the facility and magnitude of regulated pollutants emitted. Our previous analysis indicates that a biorefinery using fast pyrolysis conversion process to produce finished gasoline and diesel blendstocks with a capacity of processing 2,000 dry metric tons of biomass per day would likely be classified as a major source because several regulated pollutants (such as particulate matter, sulfur dioxide, nitrogen oxide) are estimated to exceed the 100 tons per year (tpy) major sourcemore » threshold, applicable to chemical process plants. Being subject to a major source classification could pose additional challenges associated with obtaining an air permit in a timely manner before the biorefinery can start its construction. Recent developments propose an alternative approach to utilize bio-oil produced via the fast pyrolysis conversion process by shipping it to an existing petroleum refinery, where the raw bio-oil can be blended with petroleum-based feedstocks (e.g., vacuum gas oil) to produce gasoline and diesel blendstocks with renewable content. Without having to hydro-treat raw bio-oil, a biorefinery is likely to reduce its potential-to-emit to below the 100 tpy major source threshold, and therefore expedite its permitting process. We compare the PTE estimates for the two biorefinery designs with and without hydrotreating of bio-oils and examine the air permitting implications on potential air permit classification and discuss the best available control technology requirements for the major source biorefinery utilizing hydrotreating operation. Our analysis is expected to provide useful information to new biofuel project developers to identify opportunities to overcome challenges associated with air permitting.« less

Improving the circular economy via hydrothermal processing of high-density waste plastics.

PubMed

Helmer Pedersen, Thomas; Conti, Federica

2017-10-01

Rising environmental concerns on climate changes are causing an increasing attention on circular economies. The plastic economy, in particular, is in focus due to the accelerating consumption of plastics, mainly derived from virgin feedstock, combined with the lack of plastic recycling strategies. This work presents a novel outlook on the potential of using supercritical hydrothermal processing of waste plastic fractions for tertiary recycling. The study investigates hydrothermal processing of nine different, high-density types of plastics into original resin monomers and other value-added chemical compounds. The outlook presents conversion yields, carbon balances, and chemical details on the products obtained. It is found that all the investigated resins are prone to hydrothermal treatment, and that high yields of monomers and high value compounds (up to nearly 100%), suitable for chemicals and fuels applications, can be obtained. For instance, for polycarbonate, styrene-butadiene, poly(lactic acid), poly(ethylene terephthalate), and poly(butylene terephthalate), original monomeric compounds can be reclaimed for manufacturing new resins. The promising results presented demonstrate that hydrothermal processing of high-density plastics is a prospective technology for increasing the circularity of the plastic economy. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Conversion of Carboxylic Acids to Ketones: A Repeated Discovery

ERIC Educational Resources Information Center

Nicholson, John W.; Wilson, Alan D.

2004-01-01

The conversion of carboxylic acids to ketones is a useful chemical transformation with a long history. Several chemists have claimed that they discovered the conversion of carboxylic acids to ketones yet in fact the reaction is actually known for centuries.

Catalyst mixtures

DOEpatents

Masel, Richard I.; Rosen, Brian A.

2017-02-14

Catalysts that include at least one catalytically active element and one helper catalyst can be used to increase the rate or lower the overpotential of chemical reactions. The helper catalyst can simultaneously act as a director molecule, suppressing undesired reactions and thus increasing selectivity toward the desired reaction. These catalysts can be useful for a variety of chemical reactions including, in particular, the electrochemical conversion of CO.sub.2 or formic acid. The catalysts can also suppress H.sub.2 evolution, permitting electrochemical cell operation at potentials below RHE. Chemical processes and devices using the catalysts are also disclosed, including processes to produce CO, OH.sup.-, HCO.sup.-, H.sub.2CO, (HCO.sub.2).sup.-, H.sub.2CO.sub.2, CH.sub.3OH, CH.sub.4, C.sub.2H.sub.4, CH.sub.3CH.sub.2OH, CH.sub.3COO.sup.-, CH.sub.3COOH, C.sub.2H.sub.6, O.sub.2, H.sub.2, (COOH).sub.2, or (COO.sup.-).sub.2, and a specific device, namely, a CO.sub.2 sensor.

Integrated chemical and multi-scale structural analyses for the processes of acid pretreatment and enzymatic hydrolysis of corn stover.

PubMed

Chen, Longjian; Li, Junbao; Lu, Minsheng; Guo, Xiaomiao; Zhang, Haiyan; Han, Lujia

2016-05-05

Corn stover was pretreated with acid under moderate conditions (1.5%, w/w, 121°C, 60min), and kinetic enzymolysis experiments were performed on the pretreated substrate using a mixture of Celluclast 1.5L (20FPU/g dry substrate) and Novozyme 188 (40CBU/g dry substrate). Integrated chemical and multi-scale structural methods were then used to characterize both processes. Chemical analysis showed that acid pretreatment removed considerable hemicellulose (from 19.7% in native substrate to 9.28% in acid-pretreated substrate) and achieved a reasonably high conversion efficiency (58.63% of glucose yield) in the subsequent enzymatic hydrolysis. Multi-scale structural analysis indicated that acid pretreatment caused structural changes via cleaving acetyl linkages, solubilizing hemicellulose, relocating cell wall surfaces and enlarging substrate porosity (pore volume increased from 0.0067cm(3)/g in native substrate to 0.019cm(3)/g in acid-pretreated substrate), thereby improving the polysaccharide digestibility. Copyright © 2016 Elsevier Ltd. All rights reserved.

Physical and chemical characterization of petroleum products by GC-MS.

PubMed

Mendez, A; Meneghini, R; Lubkowitz, J

2007-01-01

There is a need for reliable and fast means of monitoring refining, conversion, and upgrading processes aiming to increase the yield of light distillates, and thus, reducing the oil barrel bottoms. By simultaneously utilizing the FID and mass selective detectors while splitting the column effluent in a controlled way, it is possible to obtain identical gas chromatograms and total ion chromatograms from a single run. This means that besides the intensity vs. time graphs, the intensity vs. mass and boiling point can also be obtained. As a result, physical and chemical characterization can be performed in a simple and rapid manner. Experimental results on middle, heavy distillates, and crude oil fractions show clearly the effect of upgrading processes on the chemical composition and yields of diesel, jet fuels, and high vacuum gasoil fractions. The methodology is fully compliant with ASTM D-2887, D-7213, D-6352, and D7169 for simulated distillation and the previously mentioned mass spectrometry standards. The group type analysis correlated satisfactorily with high-performance liquid chromatography data.

From minerals to hillslopes: Towards an integrated framework for interpreting chemical and physical erosion

NASA Astrophysics Data System (ADS)

Hahm, W.; Riebe, C. S.; Ferrier, K.; Kirchner, J. W.

2011-12-01

Traditional frameworks for conceptualizing hillslope denudation distinguish between the movement of mass in solution (chemical erosion) and mass moved via mechanical processes (physical erosion). At the hillslope scale, physical and chemical erosion rates can be quantified by combining measurements of regolith chemistry with cosmogenic nuclide concentrations in bedrock and sediment, while basin-scale rates are often inferred from riverine solute and sediment loads. These techniques integrate the effects of numerous weathering and erosion mechanisms and do not provide prima facie information about the precise nature and scale of those mechanisms. For insight into erosional process, physical erosion has been considered in terms of two limiting regimes. When physical erosion outpaces weathering front advance, regolith is mobilized downslope as soon as it is sufficiently loosened by weathering, and physical erosion rates are limited by rates of mobile regolith production. This is commonly termed weathering-limited erosion. Conversely, when weathering front advance outpaces erosion, the mobile regolith layer grows thicker over time, and physical erosion rates are limited by the efficiency of downslope transport processes. This is termed transport-limited erosion. This terminology brings the description of hillslope evolution closer to the realm of essential realism, to the extent that measurable quantities from the field can be cast in a process-based framework. An analogous process-limitation framework describes chemical erosion. In supply-limited chemical erosion, chemical weathering depletes regolith of its reactive phases during residence on a hillslope, and chemical erosion rates are limited by the supply of fresh minerals to the weathering zone. Alternatively, hillslopes may exhibit kinetic-limited chemical erosion, where physical erosion transports regolith downslope before weatherable phases are completely removed by chemical erosion. We show how supply- and kinetic-limited chemical erosion can be distinguished from one another using data from a global compilation of physical and chemical erosion rates. As a step towards understanding these rates at the level of essential realism, we explore how the hillslope-scale regimes of supply- and kinetic-limited chemical erosion relate to existing conceptual frameworks that interpret weathering rates in terms of transport- and kinetic-limitation at the mineral scale.

Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Resasco, Daniel; Lobban, Lance; Crossley, Steven

The goal was to develop a biomass conversion process that optimizes fractionation and conversion to maximize Carbon efficiency and Hydrogen consumption to obtain drop-in fuels. Selective fractionation of raw biomass was obtained via multi-stage thermal fractionation to produce different streams that are enriched in a particular chemical family (acids, furanics or phenolics). These streams were later catalytically upgraded in both liquid and vapor phase to perform C-C bond formation and hydrodeoxygenation. Among various upgrading strategies investigated we have identified an effective path in which cyclopentanone is a crucial intermediate that can be derived from furfural and other furanics obtained inmore » high concentrations from this thermal staged process. Cyclopentanone is a very versatile molecule, which can couple with itself to product high quality jet-fuel, or couple with phenolic or furanics to create long chain molecules. These (mono-oxygenated) compounds in the correct molecular weight fuel range can be hydrotreated to direct drop-in fuels. Interestingly, we have found that the conversion of furfural to cyclopentanone is not affected by the presence of acetic acid, and, more interestingly, it is enhanced by the presence of water. These are very significant findings, since water and acetic acid are always present in all streams from the primary conversion stage. These results have allowed to complete detailed life-cycle assessment and techno-economic analysis that have been back-fed to the experimentalists to refine the catalyst selection and process operations with the objective of maximizing C efficiency at minimum H utilization. These combined investigations have opened the possibility of an economically and technologically effective process that could result in commercial fuels produced from renewable sources at a cost that might be competitive with fossil fuels.« less

Fundamental Aspects of Zeolite Waste Form Production by Hot Isostatic Pressing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jubin, Robert Thomas; Bruffey, Stephanie H.; Jordan, Jacob A.

The direct conversion of iodine-bearing sorbents into a stable waste form is a research topic of interest to the US Department of Energy. The removal of volatile radioactive 129I from the off-gas of a nuclear fuel reprocessing facility will be necessary in order to comply with the regulatory requirements that apply to facilities sited within the United States (Jubin et al., 2012a), and any iodine-containing media or solid sorbents generated by this process would contain 129I and would be destined for eventual geological disposal. While recovery of iodine from some sorbents is possible, a method to directly convert iodineloaded sorbentsmore » to a durable waste form with little or no additional waste materials being formed and a potentially reduced volume would be beneficial. To this end, recent studies have investigated the conversion of iodine-loaded silver mordenite (I-AgZ) directly to a waste form by hot isostatic pressing (HIPing) (Bruffey and Jubin, 2015). Silver mordenite (AgZ), of the zeolite class of minerals, is under consideration for use in adsorbing iodine from nuclear reprocessing off-gas streams. Direct conversion of I-AgZ by HIPing may provide the following benefits: (1) a waste form of high density that is tolerant to high temperatures, (2) a waste form that is not significantly chemically hazardous, and (3) a robust conversion process that requires no pretreatment.« less

Heterogeneous catalytic conversion of CO2: a comprehensive theoretical review.

PubMed

Li, Yawei; Chan, Siew Hwa; Sun, Qiang

2015-05-21

The conversion of CO2 into fuels and useful chemicals has been intensively pursued for renewable, sustainable and green energy. However, due to the negative adiabatic electron affinity (EA) and large ionization potential (IP), the CO2 molecule is chemically inert, thus making the conversion difficult under normal conditions. Novel catalysts, which have high stability, superior efficiency and low cost, are urgently needed to facilitate the conversion. As the first step to design such catalysts, understanding the mechanisms involved in CO2 conversion is absolutely indispensable. In this review, we have summarized the recent theoretical progress in mechanistic studies based on density functional theory, kinetic Monte Carlo simulation, and microkinetics modeling. We focus on reaction channels, intermediate products, the key factors determining the conversion of CO2 in solid-gas interface thermocatalytic reduction and solid-liquid interface electrocatalytic reduction. Furthermore, we have proposed some possible strategies for improving CO2 electrocatalysis and also discussed the challenges in theory, model construction, and future research directions.

CO2 Capture and Conversion on Rutile TiO2(110) in the Water Environment: Insight by First-Principles Calculations.

PubMed

Yin, Wen-Jin; Krack, Matthias; Wen, Bo; Ma, Shang-Yi; Liu, Li-Min

2015-07-02

The conversion of CO2 by the virtue of sunlight has the great potential to produce useful fuels or valuable chemicals while decreasing CO2 emission from the traditional fossil fuels. Here, we use the first-principles calculations combined with the periodic continuum solvation model (PCSM) to explore the adsorption and reactivity of CO2 on rutile TiO2(110) in the water environment. The results exhibit that both adsorption structures and reactivity of CO2 are greatly affected by water coadsorption on rutile TiO2(110). In particular, the solvation effect can change the most stable adsorption configuration of CO2 and H2O on rutile TiO2(110). In addition, the detailed conversion mechanism of CO2 reduction is further explored in the water environment. The results reveal that the solvation effect cannot only greatly decrease the energy barrier of CO2 reduction but also affect the selectivity of the reaction processes. These results presented here show the importance of the aqueous solution, which should be helpful to understand the detailed reaction processes of photocatalysts.

Process simulation and cost analysis for removing inorganics from wood chips using combined mechanical and chemical preprocessing

DOE PAGES

Hu, Hongqiang; Westover, Tyler L.; Cherry, Robert; ...

2016-10-03

Inorganic species (ash) in biomass feedstocks negatively impact thermochemical and biochemical energy conversion processes. In this work, a process simulation model is developed to model the reduction in ash content of loblolly logging residues using a combination of air classification and dilute-acid leaching. Various scenarios are considered, and it is found that costs associated with discarding high-ash material from air classification are substantial. The costs of material loss can be reduced by chemical leaching the high-ash fraction obtained from air classification. The optimal leaching condition is found to be approximately 0.1 wt% sulfuric acid at 24°C. In example scenarios, totalmore » process costs in the range of $10-12/dry tonnes of product are projected that result in a removal of 11, 66, 53 and 86% of organics, total ash (inorganics), alkaline earth metals and phosphorus (AAEMS+P), and silicon, respectively. Here, sensitivity analyses indicate that costs associated with loss of organic material during processing (yield losses), brine disposal, and labor have the greatest potential to impact the total processing cost.« less

Chapter 28: Nanomaterials for Energy Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hurst, Katherine E; Luther, Joseph M; Ban, Chunmei

2017-01-02

A wide variety of nanomaterials have been applied to energy related applications, including nanofibers, nanocrystalline materials, nanoparticles, and thin film nanocoatings. Solid-state lighting offers significant advantages in energy efficiency compared to traditional lighting technologies. The potential for nanostructured solid-state lighting devices is excellent as it enjoys significant economic drivers in energy efficiency. Fuel cells convert chemical energy to electrical energy through electrochemical reactions at an anode and cathode. The conversion of biomass to fuels and chemicals offers great potential to reduce energy dependence on petroleum and reduce green house gas emissions. Batteries involve the production and storage of electrical charge,more » the transfer of cations and electrical current, each based on electrochemical reactions and chemical reactants. Battery performance relies on the complex processes and factors that affect the transport of charge in the reactants, and across the interface between the chemical phases.« less

Bioisostere Identification by Determining the Amino Acid Binding Preferences of Common Chemical Fragments.

PubMed

Sato, Tomohiro; Hashimoto, Noriaki; Honma, Teruki

2017-12-26

To assist in the structural optimization of hit/lead compounds during drug discovery, various computational approaches to identify potentially useful bioisosteric conversions have been reported. Here, the preference of chemical fragments to hydrogen bonds with specific amino acid residues was used to identify potential bioisosteric conversions. We first compiled a data set of chemical fragments frequently occurring in complex structures contained in the Protein Data Bank. We then used a computational approach to determine the amino acids to which these chemical fragments most frequently hydrogen bonded. The results of the frequency analysis were used to hierarchically cluster chemical fragments according to their amino acid preferences. The Euclid distance between amino acid preferences of chemical fragments for hydrogen bonding was then compared to MMP information in the ChEMBL database. To demonstrate the applicability of the approach for compound optimization, the similarity of amino acid preferences was used to identify known bioisosteric conversions of the epidermal growth factor receptor inhibitor gefitinib. The amino acid preference distance successfully detected bioisosteric fragments corresponding to the morpholine ring in gefitinib with a higher ROC score compared to those based on topological similarity of substituents and frequency of MMP in the ChEMBL database.

Cellulose hydrogenolysis with the use of the catalysts supported on hypercrosslinked polystyrene

NASA Astrophysics Data System (ADS)

Sulman, E. M.; Matveeva, V. G.; Manaenkov, O. V.; Filatova, A. E.; Kislitza, O. V.; Doluda, V. Yu.; Rebrov, E. V.; Sidorov, A. I.; Shimanskaya, E. I.

2016-11-01

The study presents the results of cellulose hydrolytic hydrogenation process in subcritical water in the presence of Ru-containing catalysts based on hypercrosslinked polystyrene (HPS) MN-270 and its functionalized analogues: NH2-HPS (MN-100) and SO3H-HPS (MN-500). It was shown that the replacement of the traditional support (carbon) by HPS increases the yield of the main cellulose conversion products - polyols - important intermediates for the chemical industry. The catalysts were characterized using transmission electron microscopy (TEM), high resolution TEM, and porosity measurements. Catalytic studies demonstrated that the catalyst containing 1.0% Ru and based on MN-270 is the most active. The total yield of sorbitol and mannitol was 50% on the average at 85% cellulose conversion.

Light changes the atmospheric reactivity of soot

PubMed Central

Monge, Maria Eugenia; D’Anna, Barbara; Mazri, Linda; Giroir-Fendler, Anne; Ammann, Markus; Donaldson, D. J.; George, Christian

2010-01-01

Soot particles produced by incomplete combustion processes are one of the major components of urban air pollution. Chemistry at their surfaces lead to the heterogeneous conversion of several key trace gases; for example NO2 interacts with soot and is converted into HONO, which rapidly photodissociates to form OH in the troposphere. In the dark, soot surfaces are rapidly deactivated under atmospheric conditions, leading to the current understanding that soot chemistry affects tropospheric chemical composition only in a minor way. We demonstrate here that the conversion of NO2 to HONO on soot particles is drastically enhanced in the presence of artificial solar radiation, and leads to persistent reactivity over long periods. Soot photochemistry may therefore be a key player in urban air pollution. PMID:20080580

Microwave-assisted solid phase conversion study of Meldrum's acid to ethylenetetracarboxylic dianhydride (C 6O 6)

NASA Astrophysics Data System (ADS)

Taherpour, Avat (Arman)

2010-01-01

Utilization of microwave irradiation provides an effective method for fast synthesizing of some important compounds. Microwave-assisted solid phase is an especial class in chemical synthesis. By the use of MW-irradiation on chemicals, sometimes interesting results can be seen. The synthesis of the interesting molecule ethylenetetracarboxylic dianhydride (C 6O 6) was attempted with a few different methods. In this study, the microwave-assisted solid phase conversion of Meldrum's acid to ethylenetetracarboxylic dianhydride was reported. This conversion was characterized by FT-IR, GC/MS and NMR spectroscopy results.

Quantitative characterization of the aqueous fraction from hydrothermal liquefaction of algae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maddi, Balakrishna; Panisko, Ellen; Wietsma, Thomas

Aqueous streams generated from hydrothermal liquefaction contain approximately 30% of the total carbon present from the algal feed. Hence, this aqueous carbon must be utilized to produce liquid fuels and/or specialty chemicals for economic sustainability of hydrothermal liquefaction on industrial scale. In this study, aqueous fractions produced from the hydrothermal liquefaction of fresh water and saline water algal cultures were analyzed using a wide variety of analytical instruments to determine their compositional characteristics. This study will also inform researchers designing catalysts for down-stream processing such as high-pressure catalytic conversion of organics in aqueous phase, catalytic hydrothermal gasification, and biological conversions.more » Organic chemical compounds present in all eight aqueous fractions were identified using two-dimensional gas chromatography equipped with time-of-flight mass spectrometry. Identified compounds include organic acids, nitrogen compounds and aldehydes/ketones. Conventional gas chromatography and liquid chromatography methods were utilized to quantify the identified compounds. Inorganic species in the aqueous stream of hydrothermal liquefaction of algae were identified using ion chromatography and inductively coupled plasma optical emission spectrometer. The concentrations of organic chemical compounds and inorganic species are reported. The amount quantified carbon ranged from 45 to 72 % of total carbon in the aqueous fractions.« less

Effects of lignin structure on hydrodeoxygenation reactivity of pine wood lignin to valuable chemicals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Hongliang; Ben, Haoxi; Southeast Univ., Nanjing

Hydrodeoxygenation (HDO) of two dilute acid flow through pretreated softwood lignin samples, including residual lignin in pretreated solid residues (ReL) and recovered insoluble lignin in pretreated liquid (RISL), with apparent different physical and chemical structures, was comprehensively studied. A combination of catalysts (HY zeolite and Ru/Al 2O 3) was employed to investigate the effects of lignin structures, especially condensed structures, on the HDO upgrading process. Results indicated that the condensed structure and short side chains in lignin hindered its HDO conversion under different reaction conditions, including catalyst loading and composition, hydrogen pressure, and reaction time. In addition to lignin structure,more » HY zeolite was found crucial for lignin depolymerization, while Ru/Al 2O 3 and relatively high hydrogen pressure (4 MPa) were necessary for upgrading unstable oxy-compounds to cyclohexanes at high selectivity (>95 wt %). Since the lignin structure essentially affects its reactivity during HDO conversion, the yield and selectivity of HDO products can be predicted by detailed characterization of the lignin structure. Furthermore, the insights gained from this study in the fundamental reaction mechanisms based on the lignin structure will facilitate upgrading of lignin to high-value products for applications in the production of both fuels and chemicals.« less

Effects of lignin structure on hydrodeoxygenation reactivity of pine wood lignin to valuable chemicals

DOE PAGES

Wang, Hongliang; Ben, Haoxi; Southeast Univ., Nanjing; ...

2017-01-05

Hydrodeoxygenation (HDO) of two dilute acid flow through pretreated softwood lignin samples, including residual lignin in pretreated solid residues (ReL) and recovered insoluble lignin in pretreated liquid (RISL), with apparent different physical and chemical structures, was comprehensively studied. A combination of catalysts (HY zeolite and Ru/Al 2O 3) was employed to investigate the effects of lignin structures, especially condensed structures, on the HDO upgrading process. Results indicated that the condensed structure and short side chains in lignin hindered its HDO conversion under different reaction conditions, including catalyst loading and composition, hydrogen pressure, and reaction time. In addition to lignin structure,more » HY zeolite was found crucial for lignin depolymerization, while Ru/Al 2O 3 and relatively high hydrogen pressure (4 MPa) were necessary for upgrading unstable oxy-compounds to cyclohexanes at high selectivity (>95 wt %). Since the lignin structure essentially affects its reactivity during HDO conversion, the yield and selectivity of HDO products can be predicted by detailed characterization of the lignin structure. Furthermore, the insights gained from this study in the fundamental reaction mechanisms based on the lignin structure will facilitate upgrading of lignin to high-value products for applications in the production of both fuels and chemicals.« less

Amylolytic bacterial lactic acid fermentation - a review.

PubMed

Reddy, Gopal; Altaf, Md; Naveena, B J; Venkateshwar, M; Kumar, E Vijay

2008-01-01

Lactic acid, an enigmatic chemical has wide applications in food, pharmaceutical, leather, textile industries and as chemical feed stock. Novel applications in synthesis of biodegradable plastics have increased the demand for lactic acid. Microbial fermentations are preferred over chemical synthesis of lactic acid due to various factors. Refined sugars, though costly, are the choice substrates for lactic acid production using Lactobacillus sps. Complex natural starchy raw materials used for production of lactic acid involve pretreatment by gelatinization and liquefaction followed by enzymatic saccharification to glucose and subsequent conversion of glucose to lactic acid by Lactobacillus fermentation. Direct conversion of starchy biomass to lactic acid by bacteria possessing both amylolytic and lactic acid producing character will eliminate the two step process to make it economical. Very few amylolytic lactic acid bacteria with high potential to produce lactic acid at high substrate concentrations are reported till date. In this view, a search has been made for various amylolytic LAB involved in production of lactic acid and utilization of cheaply available renewable agricultural starchy biomass. Lactobacillus amylophilus GV6 is an efficient and widely studied amylolytic lactic acid producing bacteria capable of utilizing inexpensive carbon and nitrogen substrates with high lactic acid production efficiency. This is the first review on amylolytic bacterial lactic acid fermentations till date.

MSU-Northern Bio-Energy Center of Excellence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kegel, Greg; Windy Boy, Jessica; Maglinao, Randy Latayan

The goal of this project was to establish the Bio-Energy Center (the Center) of Montana State University Northern (MSUN) as a Regional Research Center of Excellence in research, product development, and commercialization of non-food biomass for the bio-energy industry. A three-step approach, namely, (1) enhance the Center’s research and testing capabilities, (2) develop advanced biofuels from locally grown agricultural crops, and (3) educate the community through outreach programs for public understanding and acceptance of new technologies was identified to achieve this goal. The research activities aimed to address the obstacles concerning the production of biofuels and other bio-based fuel additivesmore » considering feedstock quality, conversion process, economic viability, and public awareness. First and foremost in enhancing the capabilities of the Center is the improvement of its laboratories and other physical facilities for investigating new biomass conversion technologies and the development of its manpower complement with expertise in chemistry, engineering, biology, and energy. MSUN renovated its Auto Diagnostics building and updated its mechanical and electrical systems necessary to house the state-of-the-art 525kW (704 hp) A/C Dynamometer. The newly renovated building was designated as the Advanced Fuels Building. Two laboratories, namely Biomass Conversion lab and Wet Chemistry lab were also added to the Center’s facilities. The Biomass Conversion lab was for research on the production of advanced biofuels including bio-jet fuel and bio-based fuel additives while the Wet Chemistry lab was used to conduct catalyst research. Necessary equipment and machines, such as gas chromatograph-mass spectrometry, were purchased and installed to help in research and testing. With the enhanced capabilities of the Center, research and testing activities were very much facilitated and more precise. New biofuels derived from Camelina sativa (camelina), a locally-grown oilseed crop was developed through a chemical process for converting the oil extracted into jet fuel. Promising methods of synthesizing heterogeneous metal complex catalyst that support the chemical conversion process were likewise developed. Breaking-down lignin to valuable chemicals using a metal complex catalyst was also investigated. Lignin is an organic polymer that binds around cellulose and hemicellulose fibers which strengthen cell walls in woody biomass. Test results showed promise and could lead to further exploration of using lignin for fuels and fuel additives. These findings could create another value-added product from lignin that can be sourced from beetle kill trees and product residues from cellulose ethanol plants. Coupled with these research discoveries was the provision of technical support to businesses in terms of product development and commercialization of bio-based products. This in turn opened new avenues for advancing the bio-energy industry in the region and helped support the regional agricultural-based economy through developing biofuels derived from feedstock that are grown locally. It assisted in developing biofuels that reduce exhaust emissions and improve engine performance.« less

Preparation and corrosion resistance of magnesium phytic acid/hydroxyapatite composite coatings on biodegradable AZ31 magnesium alloy.

PubMed

Zhang, Min; Cai, Shu; Zhang, Feiyang; Xu, Guohua; Wang, Fengwu; Yu, Nian; Wu, Xiaodong

2017-06-01

In this work, a magnesium phytic acid/hydroxyapatite composite coating was successfully prepared on AZ31 magnesium alloy substrate by chemical conversion deposition technology with the aim of improving its corrosion resistance and bioactivity. The influence of hydroxyapatite (HA) content on the microstructure and corrosion resistance of the coatings was investigated. The results showed that with the increase of HA content in phytic acid solution, the cracks on the surface of the coatings gradually reduced, which subsequently improved the corrosion resistance of these coated magnesium alloy. Electrochemical measurements in simulated body fluid (SBF) revealed that the composite coating with 45 wt.% HA addition exhibited superior surface integrity and significantly improved corrosion resistance compared with the single phytic acid conversion coating. The results of the immersion test in SBF showed that the composite coating could provide more effective protection for magnesium alloy substrate than that of the single phytic acid coating and showed good bioactivity. Magnesium phytic acid/hydroxyapatite composite, with the desired bioactivity, can be synthesized through chemical conversion deposition technology as protective coatings for surface modification of the biodegradable magnesium alloy implants. The design idea of the new type of biomaterial is belong to the concept of "third generation biomaterial". Corrosion behavior and bioactivity of coated magnesium alloy are the key issues during implantation. In this study, preparation and corrosion behavior of magnesium phytic acid/hydroxyapatite composite coatings on magnesium alloy were studied. The basic findings and significance of this paper are as follows: 1. A novel environmentally friendly, homogenous and crack-free magnesium phytic acid/hydroxyapatite composite coating was fabricated on AZ31 magnesium alloy via chemical conversion deposition technology with the aim of enhancing its corrosion resistance and bioactivity. The chemical conversion coatings, which are formed through the reaction between the substrate and the environment, have attracted increasing attention owing to the relative low treatment temperature, favorable bonding to substrate and simple implementation process. 2. With the increasing of hydroxyapatite (HA) content, the crack width in the composite coatings and the thickness of the coatings exhibit obviously decreased. The reason is probably that when adding HA into the phytic acid solution, the amount of active hydroxyl groups in the phytic acid are reduced via forming the coordination bond between P-OH groups from phytic acid and P-OH groups from the surface of HA, thus decreasing the coating thickness and hydrogen formation, as well as avoiding coating cracking. 3. By adjusting the HA content to 45 wt.%, a dense and relatively smooth composite coating with ~1.4 μm thickness is obtained on magnesium alloy, and exhibits high corrosion resistance and good bioactivity when compared with the single phytic acid conversion coating.

Strategies for Stabilizing Nitrogenous Compounds in ECLSS Wastewater: Top-Down System Design and Unit Operation Selection with Focus on Bio-Regenerative Processes for Short and Long Term Scenarios

NASA Technical Reports Server (NTRS)

Lunn, Griffin M.

2011-01-01

Water recycling and eventual nutrient recovery is crucial for surviving in or past low earth orbit. New approaches and syste.m architecture considerations need to be addressed to meet current and future system requirements. This paper proposes a flexible system architecture that breaks down pretreatment , steps into discrete areas where multiple unit operations can be considered. An overview focusing on the urea and ammonia conversion steps allows an analysis on each process's strengths and weaknesses and synergy with upstream and downstream processing. Process technologies to be covered include chemical pretreatment, biological urea hydrolysis, chemical urea hydrolysis, combined nitrification-denitrification, nitrate nitrification, anammox denitrification, and regenerative ammonia absorption through struvite formation. Biological processes are considered mainly for their ability to both maximize water recovery and to produce nutrients for future plant systems. Unit operations can be considered for traditional equivalent system mass requirements in the near term or what they can provide downstream in the form of usable chemicals or nutrients for the long term closed-loop ecological control and life support system. Optimally this would allow a system to meet the former but to support the latter without major modification.

CARBON DIOXIDE FIXATION.

DOE Office of Scientific and Technical Information (OSTI.GOV)

FUJITA,E.

2000-01-12

Solar carbon dioxide fixation offers the possibility of a renewable source of chemicals and fuels in the future. Its realization rests on future advances in the efficiency of solar energy collection and development of suitable catalysts for CO{sub 2} conversion. Recent achievements in the efficiency of solar energy conversion and in catalysis suggest that this approach holds a great deal of promise for contributing to future needs for fuels and chemicals.

Industrial biomanufacturing: The future of chemical production.

PubMed

Clomburg, James M; Crumbley, Anna M; Gonzalez, Ramon

2017-01-06

The current model for industrial chemical manufacturing employs large-scale megafacilities that benefit from economies of unit scale. However, this strategy faces environmental, geographical, political, and economic challenges associated with energy and manufacturing demands. We review how exploiting biological processes for manufacturing (i.e., industrial biomanufacturing) addresses these concerns while also supporting and benefiting from economies of unit number. Key to this approach is the inherent small scale and capital efficiency of bioprocesses and the ability of engineered biocatalysts to produce designer products at high carbon and energy efficiency with adjustable output, at high selectivity, and under mild process conditions. The biological conversion of single-carbon compounds represents a test bed to establish this paradigm, enabling rapid, mobile, and widespread deployment, access to remote and distributed resources, and adaptation to new and changing markets. Copyright © 2017, American Association for the Advancement of Science.

Proceedings of "Optical Probes of Dynamics in Complex Environments"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sension, R; Tokmakoff, A

2008-04-01

This document contains the proceedings from the symposium on Optical Probes of Dynamics in Complex Environments, which organized as part of the 235th National Meeting of the American Chemical Society in New Orleans, LA from April 6 to 10, 2008. The study of molecular dynamics in chemical reaction and biological processes using time ƒresolved spectroscopy plays an important role in our understanding of energy conversion, storage, and utilization problems. Fundamental studies of chemical reactivity, molecular rearrangements, and charge transport are broadly supported by the DOE Office of Science because of their role in the development of alternative energy sources, themore » understanding of biological energy conversion processes, the efficient utilization of existing energy resources, and the mitigation of reactive intermediates in radiation chemistry. In addition, time resolved spectroscopy is central to all of DOEs grand challenges for fundamental energy science. This symposium brought together leaders in the field of ultrafast spectroscopy, including experimentalists, theoretical chemists, and simulators, to discuss the most recent scientific and technological advances. DOE support for this conference was used to help young US and international scientists travel to the meeting. The latest technology in ultrafast infrared, optical, and xray spectroscopy and the scientific advances that these methods enable were covered. Particular emphasis was placed on new experimental methods used to probe molecular dynamics in liquids, solids, interfaces, nanostructured materials, and biomolecules.« less

Lignin solubilization and aqueous phase reforming for the production of aromatic chemicals and hydrogen.

PubMed

Zakzeski, Joseph; Weckhuysen, Bert M

2011-03-21

The solubilization and aqueous phase reforming of lignin, including kraft, soda, and alcell lignin along with sugarcane bagasse, at low temperatures (T≤498 K) and pressures (P≤29 bar) is reported for the first time for the production of aromatic chemicals and hydrogen. Analysis of lignin model compounds and the distribution of products obtained during the lignin aqueous phase reforming revealed that lignin was depolymerized through disruption of the abundant β-O-4 linkages and, to a lesser extent, the 5-5' carbon-carbon linkages to form monomeric aromatic compounds. The alkyl chains contained on these monomeric compounds were readily reformed to produce hydrogen and simple aromatic platform chemicals, particularly guaiacol and syringol, with the distribution of each depending on the lignin source. The methoxy groups present on the aromatic rings were subject to hydrolysis to form methanol, which was also readily reformed to produce hydrogen and carbon dioxide. The composition of the isolated yields of monomeric aromatic compounds and overall lignin conversion based on these isolated yields varied from 10-15% depending on the lignin sample, with the balance consisting of gaseous products and residual solid material. Furthermore, we introduce the use of a high-pressure autoclave with optical windows and an autoclave with ATR-IR sentinel for on-line in situ spectroscopic monitoring of biomass conversion processes, which provides direct insight into, for example, the solubilization process and aqueous phase reforming reaction of lignin. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-yielding continuous-flow synthesis of antimalarial drug hydroxychloroquine

PubMed Central

Telang, Nakul S; Kong, Caleb J; Verghese, Jenson; Gilliland III, Stanley E; Ahmad, Saeed; Dominey, Raymond N

2018-01-01

Numerous synthetic methods for the continuous preparation of fine chemicals and active pharmaceutical ingredients (API’s) have been reported in recent years resulting in a dramatic improvement in process efficiencies. Herein we report a highly efficient continuous synthesis of the antimalarial drug hydroxychloroquine (HCQ). Key improvements in the new process include the elimination of protecting groups with an overall yield improvement of 52% over the current commercial process. The continuous process employs a combination of packed bed reactors with continuous stirred tank reactors for the direct conversion of the starting materials to the product. This high-yielding, multigram-scale continuous synthesis provides an opportunity to achieve increase global access to hydroxychloroquine for treatment of malaria. PMID:29623120

Fossil energy program

NASA Astrophysics Data System (ADS)

McNeese, L. E.

1981-12-01

The progress made during the period from July 1 through September 30 for the Oak Ridge National Laboratory research and development projects in support of the increased utilization of coal and other fossil fuels as sources of clean energy is reported. The following topics are discussed: coal conversion development, chemical research and development, materials technology, fossil energy materials program, liquefaction projects, component development, process analysis, environmental control technology, atmospheric fluidized bed combustion, underground coal gasification, coal preparation and waste utilization.

The importance of inclusion of kinetic information in the extrapolation of high-to-low concentrations for human limit setting.

PubMed

Geraets, Liesbeth; Zeilmaker, Marco J; Bos, Peter M J

2018-01-05

Human health risk assessment of inhalation exposures generally includes a high-to-low concentration extrapolation. Although this is a common step in human risk assessment, it introduces various uncertainties. One of these uncertainties is related to the toxicokinetics. Many kinetic processes such as absorption, metabolism or excretion can be subject to saturation at high concentration levels. In the presence of saturable kinetic processes of the parent compound or metabolites, disproportionate increases in internal blood or tissue concentration relative to the external concentration administered may occur resulting in nonlinear kinetics. The present paper critically reviews human health risk assessment of inhalation exposure. More specific, it emphasizes the importance of kinetic information for the determination of a safe exposure in human risk assessment of inhalation exposures assessed by conversion from a high animal exposure to a low exposure in humans. For two selected chemicals, i.e. methyl tert-butyl ether and 1,2-dichloroethane, PBTK-modelling was used, for illustrative purposes, to follow the extrapolation and conversion steps as performed in existing risk assessments for these chemicals. Human health-based limit values based on an external dose metric without sufficient knowledge on kinetics might be too high to be sufficiently protective. Insight in the actual internal exposure, the toxic agent, the appropriate dose metric, and whether an effect is related to internal concentration or dose is important. Without this, application of assessment factors on an external dose metric and the conversion to continuous exposure results in an uncertain human health risk assessment of inhalation exposures. Copyright © 2017 Elsevier B.V. All rights reserved.

Nanometals for Solar-to-Chemical Energy Conversion: From Semiconductor-Based Photocatalysis to Plasmon-Mediated Photocatalysis and Photo-Thermocatalysis.

PubMed

Meng, Xianguang; Liu, Lequan; Ouyang, Shuxin; Xu, Hua; Wang, Defa; Zhao, Naiqin; Ye, Jinhua

2016-08-01

Nanometal materials play very important roles in solar-to-chemical energy conversion due to their unique catalytic and optical characteristics. They have found wide applications from semiconductor photocatalysis to rapidly growing surface plasmon-mediated heterogeneous catalysis. The recent research achievements of nanometals are reviewed here, with regard to applications in semiconductor photocatalysis, plasmonic photocatalysis, and plasmonic photo-thermocatalysis. As the first important topic discussed here, the latest progress in the design of nanometal cocatalysts and their applications in semiconductor photocatalysis are introduced. Then, plasmonic photocatalysis and plasmonic photo-thermocatalysis are discussed. A better understanding of electron-driven and temperature-driven catalytic behaviors over plasmonic nanometals is helpful to bridge the present gap between the communities of photocatalysis and conventional catalysis controlled by temperature. The objective here is to provide instructive information on how to take the advantages of the unique functions of nanometals in different types of catalytic processes to improve the efficiency of solar-energy utilization for more practical artificial photosynthesis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Towards cell-free isobutanol production: Development of a novel immobilized enzyme system.

PubMed

Grimaldi, Joseph; Collins, Cynthia H; Belfort, Georges

2016-01-01

Producing fuels and chemical intermediates with cell cultures is severely limited by low product concentrations (≤0.2%(v/v)) due to feedback inhibition, cell instability, and lack of economical product recovery processes. We have developed an alternate simplified production scheme based on a cell-free immobilized enzyme system. Two immobilized enzymes (keto-acid decarboxylase (KdcA) and alcohol dehydrogenase (ADH)) and one enzyme in solution (formate dehydrogenase (FDH) for NADH recycle) produced isobutanol titers 8 to 20 times higher than the highest reported titers with S. cerevisiae on a mol/mol basis. These high conversion rates and low protein leaching were achieved by covalent immobilization of enzymes (ADH) and enzyme fusions (fKdcA) on methacrylate resin. The new enzyme system without in situ removal of isobutanol achieved a 55% conversion of ketoisovaleric acid to isobutanol at a concentration of 0.135 (mole isobutanol produced for each mole ketoisovaleric acid consumed). Further increasing titer will require continuous removal of the isobutanol using an in situ recovery system. © 2015 American Institute of Chemical Engineers.

Monoamines stimulate sex reversal in the saddleback wrasse.

PubMed

Larson, Earl T; Norris, David O; Gordon Grau, E; Summers, Cliff H

2003-02-15

Monoamine neurotransmitters (norepinephrine, dopamine, and serotonin) play an important role in reproduction and sexual behavior throughout the vertebrates. They are the first endogenous chemical signals in the regulation of the hypothalamo-pituitary-gonadal (HPG) axis. In teleosts with behavioral sex determination, much is known about behavioral cues that induce sex reversal. The cues are social, processed via the visual system and depend on the ratio of females to males in the population. The mechanisms by which these external behavioral cues are converted to an internal chemical regulatory process are largely unknown. The protogynous Hawaiian saddleback wrasse, Thalassoma duperrey, was used to investigate the biological pathway mediating the conversion of a social cue into neuroendocrine events regulating sex reversal. Because monoamines play an important role in the regulation of the HPG axis, they were selected as likely candidates for such a conversion. To determine if monoamines could affect sex reversal, drugs affecting monoamines were used in an attempt to either induce sex reversal under non-permissive conditions, or prevent sex reversal under permissive conditions. Increasing norepinephrine or blocking dopamine or serotonin lead to sex reversal in experimental animals under non-permissive conditions. Increasing serotonin blocked sex reversal under permissive conditions, while blocking dopamine or norepinephrine retarded the process. The results presented here demonstrate that monoamines contribute significantly to the control sex reversal. Norepinephrine stimulates initiation and completion of gonadal sex of reversal as well as color change perhaps directly via its effects on the HPG axis. Dopamine exercises inhibitory action on the initiation of sex reversal while 5-HT inhibits both initiation and completion of sex reversal. The serotonergic system appears to be an integral part of the pathway mediating the conversion of a social cue into a neuroendocrine event. The complex organization of neurochemical events controlling the psychosocial, physiological, and anatomical events that constitute reversal of sexual identity includes monoamine neurotransmitters. Copyright 2003 Elsevier Science (USA)

A Review of Microwave-Assisted Reactions for Biodiesel Production

PubMed Central

Nomanbhay, Saifuddin; Ong, Mei Yin

2017-01-01

The conversion of biomass into chemicals and biofuels is an active research area as trends move to replace fossil fuels with renewable resources due to society’s increased concern towards sustainability. In this context, microwave processing has emerged as a tool in organic synthesis and plays an important role in developing a more sustainable world. Integration of processing methods with microwave irradiation has resulted in a great reduction in the time required for many processes, while the reaction efficiencies have been increased markedly. Microwave processing produces a higher yield with a cleaner profile in comparison to other methods. The microwave processing is reported to be a better heating method than the conventional methods due to its unique thermal and non-thermal effects. This paper provides an insight into the theoretical aspects of microwave irradiation practices and highlights the importance of microwave processing. The potential of the microwave technology to accomplish superior outcomes over the conventional methods in biodiesel production is presented. A green process for biodiesel production using a non-catalytic method is still new and very costly because of the supercritical condition requirement. Hence, non-catalytic biodiesel conversion under ambient pressure using microwave technology must be developed, as the energy utilization for microwave-based biodiesel synthesis is reported to be lower and cost-effective. PMID:28952536

A Review of Microwave-Assisted Reactions for Biodiesel Production.

PubMed

Nomanbhay, Saifuddin; Ong, Mei Yin

2017-06-15

The conversion of biomass into chemicals and biofuels is an active research area as trends move to replace fossil fuels with renewable resources due to society's increased concern towards sustainability. In this context, microwave processing has emerged as a tool in organic synthesis and plays an important role in developing a more sustainable world. Integration of processing methods with microwave irradiation has resulted in a great reduction in the time required for many processes, while the reaction efficiencies have been increased markedly. Microwave processing produces a higher yield with a cleaner profile in comparison to other methods. The microwave processing is reported to be a better heating method than the conventional methods due to its unique thermal and non-thermal effects. This paper provides an insight into the theoretical aspects of microwave irradiation practices and highlights the importance of microwave processing. The potential of the microwave technology to accomplish superior outcomes over the conventional methods in biodiesel production is presented. A green process for biodiesel production using a non-catalytic method is still new and very costly because of the supercritical condition requirement. Hence, non-catalytic biodiesel conversion under ambient pressure using microwave technology must be developed, as the energy utilization for microwave-based biodiesel synthesis is reported to be lower and cost-effective.

Tiny Tool Converts Light to Electricity

ERIC Educational Resources Information Center

Kamata, Masahiro; Tamamura, Yuna

2010-01-01

In Japan, junior high school students learn about energy conversion between kinetic and potential energy. In addition, they learn about energy conversion among different kinds of energy, such as mechanical, electrical, thermal, light and chemical. As for the conversion between electrical and light energy, teachers usually use lamps or LEDs to…

SUBSTITUTION REACTIONS FOR THE DETOXIFICATION OF HAZARDOUS CHEMICALS

EPA Science Inventory

Chemical Treatment is one of several treatment techniques used for the remediation of toxic and hazardous chemicals. Chemical treatment in this report is defined as substitution of halogens by hydrogens for the conversion of halogenated organic toxicant into its native hydrocarb...

Influence of feedstock particle size on lignocellulose conversion--a review.

PubMed

Vidal, Bernardo C; Dien, Bruce S; Ting, K C; Singh, Vijay

2011-08-01

Feedstock particle sizing can impact the economics of cellulosic ethanol commercialization through its effects on conversion yield and energy cost. Past studies demonstrated that particle size influences biomass enzyme digestibility to a limited extent. Physical size reduction was able to increase conversion rates to maximum of ≈ 50%, whereas chemical modification achieved conversions of >70% regardless of biomass particle size. This suggests that (1) mechanical pretreatment by itself is insufficient to attain economically feasible biomass conversion, and, therefore, (2) necessary particle sizing needs to be determined in the context of thermochemical pretreatment employed for lignocellulose conversion. Studies of thermochemical pretreatments that have taken into account particle size as a factor have exhibited a wide range of maximal sizes (i.e., particle sizes below which no increase in pretreatment effectiveness, measured in terms of the enzymatic conversion resulting from the pretreatment, were observed) from <0.15 to 50 mm. Maximal sizes as defined above were dependent on the pretreatment employed, with maximal size range decreasing as follows: steam explosion > liquid hot water > dilute acid and base pretreatments. Maximal sizes also appeared dependent on feedstock, with herbaceous or grassy biomass exhibiting lower maximal size range (<3 mm) than woody biomass (>3 mm). Such trends, considered alongside the intensive energy requirement of size reduction processes, warrant a more systematic study of particle size effects across different pretreatment technologies and feedstock, as a requisite for optimizing the feedstock supply system.

Enzymes from Extreme Environments and Their Industrial Applications

PubMed Central

Littlechild, Jennifer A.

2015-01-01

This article will discuss the importance of specific extremophilic enzymes for applications in industrial biotechnology. It will specifically address those enzymes that have applications in the area of biocatalysis. Such enzymes now play an important role in catalyzing a variety of chemical conversions that were previously carried out by traditional chemistry. The biocatalytic process is carried out under mild conditions and with greater specificity. The enzyme process does not result in the toxic waste that is usually produced in a chemical process that would require careful disposal. In this sense, the biocatalytic process is referred to as carrying out “green chemistry” which is considered to be environmentally friendly. Some of the extremophilic enzymes to be discussed have already been developed for industrial processes such as an l-aminoacylase and a γ-lactamase. The industrial applications of other extremophilic enzymes, including transaminases, carbonic anhydrases, dehalogenases, specific esterases, and epoxide hydrolases, are currently being assessed. Specific examples of these industrially important enzymes that have been studied in the authors group will be presented in this review. PMID:26528475

Catalyst activity maintenance study for the liquid phase dimethyl ether process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peng, X.D.; Toseland, B.A.; Underwood, R.P.

1995-12-31

The co-production of dimethyl ether (DME) and methanol from syngas is a process of considerable commercial attractiveness. DME coproduction can double the productivity of a LPMEOH process when using coal-derived syngas. This in itself may offer chemical producers and power companies increased flexibility and more profitable operation. DME is also known as a clean burning liquid fuel; Amoco and Haldor-Topsoe have recently announced the use of DME as an alternative diesel fuel. Moreover, DME can be an interesting intermediate in the production of chemicals such as olefins and vinyl acetate. The current APCl liquid phase dimethyl ether (LPDME) process utilizesmore » a physical mixture of a commercial methanol synthesis catalyst and a dehydration catalyst (e.g., {gamma}-alumina). While this arrangement provides a synergy that results in much higher syngas conversion per pass compared to the methanol-only process, the stability of the catalyst system suffers. The present project is aimed at reducing catalyst deactivation both by understanding the cause(s) of catalyst deactivation and by developing modified catalyst systems. This paper describes the current understanding of the deactivation mechanism.« less

Formic-acid-induced depolymerization of oxidized lignin to aromatics

NASA Astrophysics Data System (ADS)

Rahimi, Alireza; Ulbrich, Arne; Coon, Joshua J.; Stahl, Shannon S.

2014-11-01

Lignin is a heterogeneous aromatic biopolymer that accounts for nearly 30% of the organic carbon on Earth and is one of the few renewable sources of aromatic chemicals. As the most recalcitrant of the three components of lignocellulosic biomass (cellulose, hemicellulose and lignin), lignin has been treated as a waste product in the pulp and paper industry, where it is burned to supply energy and recover pulping chemicals in the operation of paper mills. Extraction of higher value from lignin is increasingly recognized as being crucial to the economic viability of integrated biorefineries. Depolymerization is an important starting point for many lignin valorization strategies, because it could generate valuable aromatic chemicals and/or provide a source of low-molecular-mass feedstocks suitable for downstream processing. Commercial precedents show that certain types of lignin (lignosulphonates) may be converted into vanillin and other marketable products, but new technologies are needed to enhance the lignin value chain. The complex, irregular structure of lignin complicates chemical conversion efforts, and known depolymerization methods typically afford ill-defined products in low yields (that is, less than 10-20wt%). Here we describe a method for the depolymerization of oxidized lignin under mild conditions in aqueous formic acid that results in more than 60wt% yield of low-molecular-mass aromatics. We present the discovery of this facile C-O cleavage method, its application to aspen lignin depolymerization, and mechanistic insights into the reaction. The broader implications of these results for lignin conversion and biomass refining are also considered.

Formic-acid-induced depolymerization of oxidized lignin to aromatics.

PubMed

Rahimi, Alireza; Ulbrich, Arne; Coon, Joshua J; Stahl, Shannon S

2014-11-13

Lignin is a heterogeneous aromatic biopolymer that accounts for nearly 30% of the organic carbon on Earth and is one of the few renewable sources of aromatic chemicals. As the most recalcitrant of the three components of lignocellulosic biomass (cellulose, hemicellulose and lignin), lignin has been treated as a waste product in the pulp and paper industry, where it is burned to supply energy and recover pulping chemicals in the operation of paper mills. Extraction of higher value from lignin is increasingly recognized as being crucial to the economic viability of integrated biorefineries. Depolymerization is an important starting point for many lignin valorization strategies, because it could generate valuable aromatic chemicals and/or provide a source of low-molecular-mass feedstocks suitable for downstream processing. Commercial precedents show that certain types of lignin (lignosulphonates) may be converted into vanillin and other marketable products, but new technologies are needed to enhance the lignin value chain. The complex, irregular structure of lignin complicates chemical conversion efforts, and known depolymerization methods typically afford ill-defined products in low yields (that is, less than 10-20wt%). Here we describe a method for the depolymerization of oxidized lignin under mild conditions in aqueous formic acid that results in more than 60wt% yield of low-molecular-mass aromatics. We present the discovery of this facile C-O cleavage method, its application to aspen lignin depolymerization, and mechanistic insights into the reaction. The broader implications of these results for lignin conversion and biomass refining are also considered.

Large eddy simulation of reactive pollutants in a deep urban street canyon: Coupling dynamics with O3-NOx-VOC chemistry.

PubMed

Zhong, Jian; Cai, Xiao-Ming; Bloss, William James

2017-05-01

A large eddy simulation (LES) model coupled with O 3 -NO x -VOC chemistry is implemented to simulate the coupled effects of emissions, mixing and chemical pre-processing within an idealised deep (aspect ratio = 2) urban street canyon under a weak wind condition. Reactive pollutants exhibit significant spatial variations in the presence of two vertically aligned unsteady vortices formed in the canyon. Comparison of the LES results from two chemical schemes (simple NO x -O 3 chemistry and a more comprehensive Reduced Chemical Scheme (RCS) chemical mechanism) shows that the concentrations of NO 2 and O x inside the street canyon are enhanced by approximately 30-40% via OH/HO 2 chemistry. NO, NO x , O 3 , OH and HO 2 are chemically consumed, while NO 2 and O x (total oxidant) are chemically produced within the canyon environment. Within-canyon pre-processing increases oxidant fluxes from the canyon to the overlying boundary layer, and this effect is greater for deeper street canyons (as found in many traditional European urban centres) than shallower (lower aspect ratio) streets. There is clear evidence of distinct behaviours for emitted chemical species and entrained chemical species, and positive (or negative) values of intensities of segregations are found between pairs of species with similar (or opposite) behaviour. The simplified two-box model underestimated NO and O 3 levels, but overestimated NO 2 levels for both the lower and upper canyon compared with the more realistic LES-chemistry model. This suggests that the segregation effect due to incomplete mixing reduces the chemical conversion rate of NO to NO 2 . This study reveals the impacts of nonlinear O 3 -NO x -VOC photochemical processes in the incomplete mixing environment and provides a better understanding of the pre-processing of emissions within canyons, prior to their release to the urban boundary layer, through the coupling of street canyon dynamics and chemistry. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nanoscale Advances in Catalysis and Energy Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yimin; Somorjai, Gabor A.

2010-05-12

In this perspective, we present an overview of nanoscience applications in catalysis, energy conversion, and energy conservation technologies. We discuss how novel physical and chemical properties of nanomaterials can be applied and engineered to meet the advanced material requirements in the new generation of chemical and energy conversion devices. We highlight some of the latest advances in these nanotechnologies and provide an outlook at the major challenges for further developments.

Ultrasound-assisted acid hydrolysis of cellulose to chemical building blocks: Application to furfural synthesis.

PubMed

Santos, Daniel; Silva, Ubiratan F; Duarte, Fabio A; Bizzi, Cezar A; Flores, Erico M M; Mello, Paola A

2018-01-01

In this work, the use of ultrasound energy for the production of furanic platforms from cellulose was investigated and the synthesis of furfural was demonstrated. Several systems were evaluated, as ultrasound bath, cup horn and probe, in order to investigate microcrystalline cellulose conversion using simply a diluted acid solution and ultrasound. Several acid mixtures were evaluated for hydrolysis, as diluted solutions of HNO 3 , H 2 SO 4 , HCl and H 2 C 2 O 4 . The influence of the following parameters in the ultrasound-assisted acid hydrolysis (UAAH) were studied: sonication temperature (30 to 70°C) and ultrasound amplitude (30 to 70% for a cup horn system) for 4 to 8molL -1 HNO 3 solutions. For each evaluated condition, the products were identified by ultra-performance liquid chromatography with high-resolution time-of-flight mass spectrometry (UPLC-ToF-MS), which provide accurate information regarding the products obtained from biomass conversion. The furfural structure was confirmed by nuclear magnetic resonance ( 1 H and 13 C NMR) spectroscopy. In addition, cellulosic residues from hydrolysis reaction were characterized using scanning electron microscopy (SEM), which contributed for a better understanding of physical-chemical effects caused by ultrasound. After process optimization, a 4molL -1 HNO 3 solution, sonicated for 60min at 30°C in a cup horn system at 50% of amplitude, lead to 78% of conversion to furfural. This mild temperature condition combined to the use of a diluted acid solution represents an important contribution for the selective production of chemical building blocks using ultrasound energy. Copyright © 2017 Elsevier B.V. All rights reserved.

Easy reuse of magnetic cross-linked enzyme aggregates of lipase B from Candida antarctica to obtain biodiesel from Chlorella vulgaris lipids.

PubMed

Picó, Enrique Angulo; López, Carmen; Cruz-Izquierdo, Álvaro; Munarriz, Mercedes; Iruretagoyena, Francisco Javier; Serra, Juan Luis; Llama, María Jesús

2018-05-12

In this work, magnetic cross-linked enzyme aggregates (mCLEAs) of CALB (lipase B from Candida antarctica) were prepared and characterized. Moreover, a method for an easy, sustainable and economic extraction of lipids from nitrogen-starved cells of Chlorella vulgaris var L3 was developed. Then, the extracted lipids (oils and free fatty acids, FFAs) were converted to biodiesel using mCLEAs and chemical acid catalysis. Among several lipid extraction methods, saponification was selected given the amount of wet microalgal biomass it can process per unit of time, its low market value, and because it allows for the use of less toxic solvents. A biodiesel conversion of 80.2 ± 4.4% was obtained by chemical catalysis (1 h at 100°C) using FFAs and methanol as the alkyl donor. However, a biodiesel conversion of more than 90% (3 h at 30°C) was obtained using mCLEAs and methanol. Both chemical and enzymatic catalysts gave biodiesel with similar fatty acid alkyl ester (FAAE) composition. Methanol, at 15% (v/v) or higher concentration, caused a decrease of lipase activity and a concomitant increase in the size of mCLEA aggregates (up to 2 μm), as measured by dynamic light scattering (DLS). The magnetic character of the novel biocatalyst permits its easy recovery and reuse, for at least ten consecutive catalytic cycles (retaining 90% of the initial biodiesel conversion), using mild reaction conditions and environmentally-friendly solvents. Copyright © 2018 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Reaction engineering for materials processing in space: Reduction of ilmenite by hydrogen and carbon monoxide

NASA Technical Reports Server (NTRS)

Zhao, Y.; Shadman, F.

1991-01-01

Oxygen is a consumable material which needs to be produced continuously in most space missions. Its use for propulsion as well as life support makes oxygen one of the largest volume chemicals to be produced in space. Production of oxygen from lunar materials is of particular interest and is very attractive possibility. The kinetics and mechanism of reduction of ilmenite by carbon monoxide and hydrogen at 800 to 1100 C were investigated. The temporal profiles of conversion for carbon monoxide have a sigmoidal shape and indicate the presence of three different stages (induction, acceleration, and deceleration) during the reduction reaction. The apparent activation energy decreases from 18 kcal/mole at 10 percent conversion to 10 kcal/mole at 50 percent conversion. The reaction is first order with respect to carbon monoxide under the experimental conditions studied. Both SEM and EDX analysis show that the diffusion of Fe product away from the reaction front and through the TiO2 phase, followed by the nucleation and growth of a separate Fe phase are important steps affecting the process kinetics. The results from hydrogen reduction show that the mechanism of ilmenite reduction by hydrogen is similar to that by carbon monoxide. However, the titanium dioxide can be further reduced by hydrogen at 800 to 1000 C. The detailed comparison and theoretical modeling of both reduction processes is presented.

Revealing the arc dynamics in a gliding arc plasmatron: a better insight to improve CO2 conversion

NASA Astrophysics Data System (ADS)

Ramakers, Marleen; Medrano, Jose A.; Trenchev, Georgi; Gallucci, Fausto; Bogaerts, Annemie

2017-12-01

A gliding arc plasmatron (GAP) is very promising for CO2 conversion into value-added chemicals, but to further improve this important application, a better understanding of the arc behavior is indispensable. Therefore, we study here for the first time the dynamic arc behavior of the GAP by means of a high-speed camera, for different reactor configurations and in a wide range of operating conditions. This allows us to provide a complete image of the behavior of the gliding arc. More specifically, the arc body shape, diameter, movement and rotation speed are analyzed and discussed. Clearly, the arc movement and shape relies on a number of factors, such as gas turbulence, outlet diameter, electrode surface, gas contraction and buoyance force. Furthermore, we also compare the experimentally measured arc movement to a state-of-the-art 3D-plasma model, which predicts the plasma movement and rotation speed with very good accuracy, to gain further insight in the underlying mechanisms. Finally, we correlate the arc dynamics with the CO2 conversion and energy efficiency, at exactly the same conditions, to explain the effect of these parameters on the CO2 conversion process. This work is important for understanding and optimizing the GAP for CO2 conversion.

Synthesis of Geraniol Esters in a Continuous-Flow Packed-Bed Reactor of Immobilized Lipase: Optimization of Process Parameters and Kinetic Modeling.

PubMed

Salvi, Harshada M; Kamble, Manoj P; Yadav, Ganapati D

2018-02-01

With increasing demand for perfumes, flavors, beverages, and pharmaceuticals, the various associated industries are resorting to different approaches to enhance yields of desired compounds. The use of fixed-bed biocatalytic reactors in some of the processes for making fine chemicals will be of great value because the reaction times could be reduced substantially as well as high conversion and yields obtained. In the current study, a continuous-flow packed-bed reactor of immobilized Candida antarctica lipase B (Novozym 435) was employed for synthesis of various geraniol esters. Optimization of process parameters such as biocatalyst screening, effect of solvent, mole ratio, temperature and acyl donors was studied in a continuous-flow packed-bed reactor. Maximum conversion of ~ 87% of geranyl propionate was achieved in 15 min residence time at 70 °C using geraniol and propionic acid with a 1:1 mol ratio. Novozym 435 was found to be the most active and stable biocatalyst among all tested. Ternary complex mechanism with propionic acid inhibition was found to fit the data.

Hydrothermal conversion of xylose, glucose, and cellulose under the catalysis of transition metal sulfates.

PubMed

Cao, Xuefei; Peng, Xinwen; Sun, Shaoni; Zhong, Linxin; Chen, Wei; Wang, Sha; Sun, Run-Cang

2015-03-15

Hydrothermal conversion (HTC) is an important thermochemical process to upgrade low-cost biomass into valuable chemicals or fuels. As compared with non-catalytic HTC, catalytic HTC shows high energy efficiency on biomass upgradation. In this work, the catalytic performances of various transition metal sulfates (Mn(2+), Fe(2+), Fe(3+), Co(2+), Ni(2+), Cu(2+), and Zn(2+)) in the HTCs of xylose, glucose, and cellulose under different conditions were explored. Among these catalysts, Zn(2+) and Ni(2+) showed obvious effects on the conversions of xylose, glucose, and cellulose into lactic acid, while Cu(2+) and Fe(3+), which could significantly accelerate the hydrolysis of cellulose into glucose at 200°C, displayed high efficiency on converting glucose and cellulose into levulinic acid and formic acid at high temperature. Additionally, significant positive correlative relationships among xylose, glucose, and cellulose degradations were observed. This study is helpful for screening appropriate catalysts for biomass upgradation through catalytic HTC of monosaccharide. Copyright © 2014 Elsevier Ltd. All rights reserved.

Optimization of levulinic acid from lignocellulosic biomass using a new hybrid catalyst.

PubMed

Ya'aini, Nazlina; Amin, Nor Aishah Saidina; Asmadi, Mohd

2012-07-01

Conversion of glucose, empty fruit bunch (efb) and kenaf to levulinic acid over a new hybrid catalyst has been investigated in this study. The characterization and catalytic performance results revealed that the physico-chemical properties of the new hybrid catalyst comprised of chromium chloride and HY zeolite increased the levulinic acid production from glucose compared to the parent catalysts. Optimization of the glucose conversion process using two level full factorial designs (2(3)) with two center points reported 55.2% of levulinic acid yield at 145.2 °C, 146.7 min and 12.0% of reaction temperature, reaction time and catalyst loading, respectively. Subsequently, the potential of efb and kenaf for producing levulinic acid at the optimum conditions was established after 53.2% and 66.1% of efficiencies were reported. The observation suggests that the hybrid catalyst has a potential to be used in biomass conversion to levulinic acid. Copyright © 2012 Elsevier Ltd. All rights reserved.

A coupled CFD and two-phase substrate kinetic model for enzymatic hydrolysis of lignocellulose

NASA Astrophysics Data System (ADS)

Danes, Nicholas; Sitaraman, Hariswaran; Stickel, Jonathan; Sprague, Michael

2017-11-01

Cost-effective production of fuels from lignocellulosic biomass is an important subject of research in order to meet the world's current and future energy demands. Enzymatic hydrolysis is one of the several steps in the biochemical conversion of biomass into fuels. This process involves the interplay of non-Newtonian fluid dynamics that happen over tens of seconds coupled with chemical reactions that happen over several hours. In this work, we present a coupled CFD-reaction model for conversion of cellulose to sugars in a benchtop mixer reactor. A subcycling approach is used to circumvent the large time scale disparity between fluid dynamics and reactions. We will present a validation study of our simulations with experiments for well-mixed and stratified reactor scenarios along with predictions for conversion rates and product concentrations at varying impeller speeds and in scaled-up reactors. This work is funded by the Bioenergy Technology Office of DOE and the NSF's Enriched Doctoral Training program (DMS-1551229).

Aqueous Lithium-Iodine Solar Flow Battery for the Simultaneous Conversion and Storage of Solar Energy.

PubMed

Yu, Mingzhe; McCulloch, William D; Beauchamp, Damian R; Huang, Zhongjie; Ren, Xiaodi; Wu, Yiying

2015-07-08

Integrating both photoelectric-conversion and energy-storage functions into one device allows for the more efficient solar energy usage. Here we demonstrate the concept of an aqueous lithium-iodine (Li-I) solar flow battery (SFB) by incorporation of a built-in dye-sensitized TiO2 photoelectrode in a Li-I redox flow battery via linkage of an I3(-)/I(-) based catholyte, for the simultaneous conversion and storage of solar energy. During the photoassisted charging process, I(-) ions are photoelectrochemically oxidized to I3(-), harvesting solar energy and storing it as chemical energy. The Li-I SFB can be charged at a voltage of 2.90 V under 1 sun AM 1.5 illumination, which is lower than its discharging voltage of 3.30 V. The charging voltage reduction translates to energy savings of close to 20% compared to conventional Li-I batteries. This concept also serves as a guiding design that can be extended to other metal-redox flow battery systems.

Fossil Energy Program

NASA Astrophysics Data System (ADS)

McNeese, L. E.

1981-01-01

Increased utilization of coal and other fossil fuel alternatives as sources of clean energy is reported. The following topics are discussed: coal conversion development, chemical research and development, materials technology, component development and process evaluation studies, technical support to major liquefaction projects, process analysis and engineering evaluations, fossil energy environmental analysis, flue gas desulfurization, solid waste disposal, coal preparation waste utilization, plant control development, atmospheric fluidized bed coal combustor for cogeneration, TVA FBC demonstration plant program technical support, PFBC systems analysis, fossil fuel applications assessments, performance assurance system support for fossil energy projects, international energy technology assessment, and general equilibrium models of liquid and gaseous fuel supplies.

Producing Hydrogen With Sunlight

NASA Technical Reports Server (NTRS)

Biddle, J. R.; Peterson, D. B.; Fujita, T.

1987-01-01

Costs high but reduced by further research. Producing hydrogen fuel on large scale from water by solar energy practical if plant costs reduced, according to study. Sunlight attractive energy source because it is free and because photon energy converts directly to chemical energy when it breaks water molecules into diatomic hydrogen and oxygen. Conversion process low in efficiency and photochemical reactor must be spread over large area, requiring large investment in plant. Economic analysis pertains to generic photochemical processes. Does not delve into details of photochemical reactor design because detailed reactor designs do not exist at this early stage of development.

Structure-processing-property correlations in thin films of conjugated polymer nanocomposites and blends

NASA Astrophysics Data System (ADS)

Sreeram, Arvind

Conjugated polymers have found several applications in recent years, in energy conversion and storage devices such as organic light emitting diodes, solar cells, batteries, and super capacitors. Thin films of polymers used for these applications need to be mechanically and thermally stable to withstand the harsh operating conditions. Although there is significant information on the optoelectronic properties of many of these polymers, there are only few studies on their mechanical properties. There is little information in the literature on how processing of these films influence mechanical properties. In the first part of this study, poly(p-phenylene vinylene) (PPV) films were prepared by thermolytic conversion of poly[p -phenylene (tetrahydrothiophenium)ethylene chloride] precursor films, at different temperatures and the kinetics of reaction was investigated using thermogravimetry and Fourier transform infrared (FTIR) spectroscopy. The mechanical properties of the films, studied using nanoindentation, showed a dependence on the extent of conversion and chemical composition of the films. The presence of chemical defects (e.g., carbonyl groups, detected using FTIR spectroscopy), was also found to have a noticeable effect on the modulus and hardness of the films. The storage modulus, E', and plasticity decreased with an increase in conversion, whereas the loss modulus, E", showed the opposite trend. Both the precursor and the fully-converted PPV films were found to have significantly lower E" than E', consistent with the glassy nature of the polymers at room temperature. In the second part of the study, polyacetylene films were synthesized by acid-catalyzed dehydration reaction of poly(vinyl alcohol) (PVA) precursor films. The kinetics of this reaction was monitored by thermogravimetry. The chemical structure of the conjugated polymer films was characterized by Raman and IR spectroscopy. Polyacetylene films incorporated with 1-propyl-3-methylimidazolium ionic liquid (IL) could be obtained in a single step reaction. The incorporation of IL in the film, not only greatly improved its mechanical properties, by acting as a plasticizer, but also imparted a dual mechanism of charge transport. The segments of conjugated double bonds imparted electronic conductivity to the films, and the IL resulted in ionic conductivity. The presence of both electronic and ionic conduction pathways in the films was confirmed by electrochemical impedance spectroscopy (EIS). These IL-imbibed conjugated polymer films are promising as materials for electrochemical energy conversion and storage. In the third part of this work, conjugated polymer films containing multiwalled carbon nanotubes (MWNT) and graphene nanoplatelets (GNP) were synthesized and characterized. PPV--MWNT nanocomposite films and PA--GNP nanocomposite films were characterized using a variety of analytical techniques including transmission electron microscopy, quasistatic and dynamic nanoindentaiton, electrochemical impedance spectroscopy, and cyclic voltammetry. Potential application of these films is in electrochemical supercapacitors.

Bioconversion study conducted by JPL

NASA Technical Reports Server (NTRS)

Kalvinskas, J.

1978-01-01

The Jet Propulsion Laboratory (JPL) of Caltech conducted a study of bioconversion as a means of identifying the role of biomass for meeting the national energy fuel and chemical requirements and the role and means for JPL-Caltech involvement in bioconversion. The bioconversion study included the following categories; biomass sources, chemicals from biomass, thermochemical conversion of biomass to fuels, biological conversion of biomass to fuels and chemicals, and basic bioconversion sciences. A detailed review is included of the bioconversion fields cited with specific conclusions and recommendations given for future research and development and overall biomass system engineering and economic studies.

A review of the technological solutions for the treatment of oily sludges from petroleum refineries.

PubMed

da Silva, Leonardo Jordão; Alves, Flávia Chaves; de França, Francisca Pessôa

2012-10-01

The activities of the oil industry have several impacts on the environment due to the large amounts of oily wastes that are generated. The oily sludges are a semi-solid material composed by a mixture of clay, silica and iron oxides contaminated with oil, produced water and the chemicals used in the production of oil. Nowadays both the treatment and management of these waste materials is essential to promote sustainable management of exploration and exploitation of natural resources. Biological, physical and chemical processes can be used to reduce environmental contamination by petroleum hydrocarbons to acceptable levels. The choice of treatment method depends on the physical and chemical properties of the waste as well as the availability of facilities to process these wastes. Literature provides some operations for treatment of oily sludges, such as landfilling, incineration, co-processing in clinkerization furnaces, microwave liquefaction, centrifugation, destructive distillation, thermal plasma, low-temperature conversion, incorporation in ceramic materials, development of impermeable materials, encapsulation and biodegradation in land farming, biopiles and bioreactors. The management of the technology to be applied for the treatment of oily wastes is essential to promote proper environmental management, and provide alternative methods to reduce, reuse and recycle the wastes.

Chemical looping combustion: A new low-dioxin energy conversion technology.

PubMed

Hua, Xiuning; Wang, Wei

2015-06-01

Dioxin production is a worldwide concern because of its persistence and carcinogenic, teratogenic, and mutagenic effects. The pyrolysis-chemical looping combustion process of disposing solid waste is an alternative to traditional solid waste incineration developed to reduce the dioxin production. Based on the equilibrium composition of the Deacon reaction, pyrolysis gas oxidized by seven common oxygen carriers, namely, CuO, NiO, CaSO4, CoO, Fe2O3, Mn3O4, and FeTiO3, is studied and compared with the pyrolysis gas directly combusted by air. The result shows that the activity of the Deacon reaction for oxygen carriers is lower than that for air. For four typical oxygen carriers (CuO, NiO, Fe2O3, and FeTiO3), the influences of temperature, pressure, gas composition, and tar on the Deacon reaction are discussed in detail. According to these simulation results, the dioxin production in China, Europe, the United States, and Japan is predicted for solid waste disposal by the pyrolysis-chemical looping combustion process. Thermodynamic analysis results in this paper show that chemical looping combustion can reduce dioxin production in the disposal of solid waste. Copyright © 2015. Published by Elsevier B.V.

An Overview of Recent Development in Composite Catalysts from Porous Materials for Various Reactions and Processes

PubMed Central

Xie, Zaiku; Liu, Zhicheng; Wang, Yangdong; Yang, Qihua; Xu, Longya; Ding, Weiping

2010-01-01

Catalysts are important to the chemical industry and environmental remediation due to their effective conversion of one chemical into another. Among them, composite catalysts have attracted continuous attention during the past decades. Nowadays, composite catalysts are being used more and more to meet the practical catalytic performance requirements in the chemical industry of high activity, high selectivity and good stability. In this paper, we reviewed our recent work on development of composite catalysts, mainly focusing on the composite catalysts obtained from porous materials such as zeolites, mesoporous materials, carbon nanotubes (CNT), etc. Six types of porous composite catalysts are discussed, including amorphous oxide modified zeolite composite catalysts, zeolite composites prepared by co-crystallization or overgrowth, hierarchical porous catalysts, host-guest porous composites, inorganic and organic mesoporous composite catalysts, and polymer/CNT composite catalysts. PMID:20559508

Using a low melting solvent mixture to extract value from wood biomass

NASA Astrophysics Data System (ADS)

Hiltunen, Jaakko; Kuutti, Lauri; Rovio, Stella; Puhakka, Eini; Virtanen, Tommi; Ohra-Aho, Taina; Vuoti, Sauli

2016-09-01

Green chemistry, sustainability and eco-efficiency are guiding the development of the next generation of industrial chemical processes. The use of non-edible lignocellulosic biomass as a source of chemicals and fuels has recently raised interest due to the need for an alternative to fossil resources. Valorisation mainly focuses on cellulose, which has been used for various industrial scale applications for decades. However, creating an economically more viable value chain would require the exploitation of the other main components, hemicellulose and lignin. Here, we present a new low melting mixture composition based in boric acid and choline chloride, and demonstrate its efficiency in the fractionation of wood-based biomass for the production of non-condensed lignin, suitable for further use in the search for sustainable industrial applications, and for the selective conversion of hemicelluloses into valuable platform chemicals.

Current advance in biological production of malic acid using wild type and metabolic engineered strains.

PubMed

Dai, Zhongxue; Zhou, Huiyuan; Zhang, Shangjie; Gu, Honglian; Yang, Qiao; Zhang, Wenming; Dong, Weiliang; Ma, Jiangfeng; Fang, Yan; Jiang, Min; Xin, Fengxue

2018-06-01

Malic acid (2-hydroxybutanedioic acid) is a four-carbon dicarboxylic acid, which has attracted great interest due to its wide usage as a precursor of many industrially important chemicals in the food, chemicals, and pharmaceutical industries. Several mature routes for malic acid production have been developed, such as chemical synthesis, enzymatic conversion and biological fermentation. With depletion of fossil fuels and concerns regarding environmental issues, biological production of malic acid has attracted more attention, which mainly consists of three pathways, namely non-oxidative pathway, oxidative pathway and glyoxylate cycle. In recent decades, metabolic engineering of model strains, and process optimization for malic acid production have been rapidly developed. Hence, this review comprehensively introduces an overview of malic acid producers and highlight some of the successful metabolic engineering approaches. Copyright © 2018 Elsevier Ltd. All rights reserved.

Tritium-field betacells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walko, R.J.; Lincoln, R.C.; Baca, W.E.

1991-01-01

Betavoltaic power sources operate by converting the nuclear decay energy of beta-emitting radioisotopes into electricity. Since they are not chemically driven, they could operate at temperatures which would either be to hot or too cold for typical chemical batteries. Further, for long lived isotopes, they offer the possibility of multi-decade active lifetimes. Two approaches are being investigated: direct and indirect conversion. Direct conversion cells consist of semiconductor diodes similar to photovoltaic cells. Beta particle directly bombard these cells, generating electron-hole pairs in the semiconductor which are converted to useful power. Many using low power flux beta emitters, wide bandgap semiconductorsmore » are required to achieve useful conversion efficiencies. The combination of tritium, as the beta emitter, and gallium phosphide (GaP), as the semiconductor converter, was evaluated. Indirect conversion betacells first convert the beta energy to light with a phosphor, and then to electricity with photovoltaic cells. An indirect conversion power source using a tritium radioluminescent (RL) light is being investigated. Our analysis indicates that this approach has the potential for significant volume and cost savings over the direct conversion method. 7 refs., 11 figs.« less

Tritium-field betacells

NASA Astrophysics Data System (ADS)

Walko, R. J.; Lincoln, R. C.; Baca, W. E.; Goods, S. H.; Negley, G. H.

Betavoltaic power sources operate by converting the nuclear decay energy of beta-emitting radioisotopes into electricity. Since they are not chemically driven, they could operate at temperatures which would either be too hot or too cold for typical chemical batteries. Further, for long lived isotopes, they offer the possibility of multi-decade active lifetimes. Two approaches are being investigated: direct and indirect conversion. Direct conversion cells consist of semiconductor diodes similar to photovoltaic cells. Beta particle directly bombard these cells, generating electron-hole pairs in the semiconductor which are converted to useful power. When using low power flux beta emitters, wide bandgap semiconductors are required to achieve useful conversion efficiencies. The combination of tritium, as the beta emitter, and gallium phosphide (GaP), as the semiconductor converter, was evaluated. Indirect conversion betacells first convert the beta energy to light with a phosphor, and then to electricity with photovoltaic cells. An indirect conversion power source using a tritium radioluminescent (RL) light is being investigated. Our analysis indicates that this approach has the potential for significant volume and cost savings over the direct conversion method.

Noncatalytic transformation of the crude lipid of ChlorellaI vulgaris into fatty acid methyl ester (FAME) with charcoal via a thermo-chemical process.

PubMed

Kwon, Eilhann E; Jeon, Young Jae; Yi, Haakrho

2013-02-01

The noncatalytic transformation of the crude lipid of Chlorella vulgaris (C. vulgaris) into fatty acid methyl ester (FAME) via a thermo-chemical process was mainly investigated in this work. The crude lipid of C. vulgaris was recovered by means of solvent extraction from C. vulgaris cultivated in a raceway pond. The conventional catalyzed transesterification of crude lipid of C. vulgaris is notably inhibited by the impurities contained in the crude lipid of C. vulgaris. These impurities are inevitably derived from the solvent extraction process for C. vulgaris. However, this work presents the noncatalytic transesterification of microalgal lipid into FAME, which could be an alternative option. For example, the noncatalytic transformation of microalgal lipid into FAME provides evidence that the esterification of free fatty acids (FFAs) and the transesterification of triglycerides can be combined into a single step less susceptible to the impurities and with a high conversion efficiency (∼97%). Copyright © 2012 Elsevier Ltd. All rights reserved.

Photocatalysis versus photosynthesis: A sensitivity analysis of devices for solar energy conversion and chemical transformations

DOE PAGES

Osterloh, Frank E.

2017-01-18

Here, the chemical literature often does not differentiate between photocatalytic (PC) and photosynthetic (PS) processes (including artificial photosynthesis) even though these reactions differ in their thermodynamics. Photocatalytic processes are thermodynamically downhill (ΔG < 0) and are merely accelerated by the catalyst, whereas photosynthetic processes are thermodynamically unfavorable (ΔG > 0) and require photochemical energy input to occur. Here we apply this differentiation to analyze the basic functions of PC and PS devices and to formulate design criteria for improved performance. As will be shown, the corresponding devices exhibit distinctly different sensitivities to their functional parameters. For example, under conditions ofmore » optimal light absorption, carrier lifetimes, and electrochemical rates, the performance of PCs is limited only by their surface area, while type 1 PS devices are limited by their carrier mobility and mass transport, and type 2 PS devices are limited by electrochemical charge-transfer selectivity. Strategies for the optimization of type 1 and 2 photosynthetic devices and photocatalysts are also discussed.« less

Effect of torrefaction on yield and quality of pyrolytic products of arecanut husk: An agro-processing wastes.

PubMed

Gogoi, Debajeet; Bordoloi, Neonjyoti; Goswami, Ritusmita; Narzari, Rumi; Saikia, Ruprekha; Sut, Debashis; Gogoi, Lina; Kataki, Rupam

2017-10-01

In the present study, arecanut husk, an agro-processing waste of areca plam industry highly prevalent in the north-eastern region of India, was investigated for its suitability as a prospective bioenergy feedstock for thermo-chemical conversion. Pretreatment of areca husk using torrefaction was performed in a fixed bed reactor with varying reaction temperature (200, 225, 250 and 275°C). The torrefied areca husk was subsequently pyrolyzed from temperature range of 300-600°C with heating rate of 40°C/min to obtain biooil and biochar. The torrefied areca husk, pyrolysis products were characterized by using different techniques. The energy and mass yield of torrefied biomass were found to be decreased with an increase in the torrefaction temperature. Further, biochar were found to be effective in removal of As (V) from aqueous solutions but efficiency of removal was better in case of torrefied biochar. Chemical composition of bio-oil is also influenced by torrefaction process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Chemical, electrochemical and photochemical molecular water oxidation catalysts.

PubMed

Bofill, Roger; García-Antón, Jordi; Escriche, Lluís; Sala, Xavier

2015-11-01

Hydrogen release from the splitting of water by simply using sunlight as the only energy source is an old human dream that could finally become a reality. This process involves both the reduction and oxidation of water into hydrogen and oxygen, respectively. While the first process has been fairly overcome, the conversion of water into oxygen has been traditionally the bottleneck process hampering the development of a sustainable hydrogen production based on water splitting. Fortunately, a revolution in this field has occurred during the past decade, since many research groups have been conducting an intense research in this area. Thus, while molecular, well-characterized catalysts able to oxidize water were scarce just five years ago, now a wide range of transition metal based compounds has been reported as active catalysts for this transformation. This review reports the most prominent key advances in the field, covering either examples where the catalysis is triggered chemically, electrochemically or photochemically. Copyright © 2014 Elsevier B.V. All rights reserved.

Hybridizing energy conversion and storage in a mechanical-to-electrochemical process for self-charging power cell.

PubMed

Xue, Xinyu; Wang, Sihong; Guo, Wenxi; Zhang, Yan; Wang, Zhong Lin

2012-09-12

Energy generation and energy storage are two distinct processes that are usually accomplished using two separated units designed on the basis of different physical principles, such as piezoelectric nanogenerator and Li-ion battery; the former converts mechanical energy into electricity, and the latter stores electric energy as chemical energy. Here, we introduce a fundamental mechanism that directly hybridizes the two processes into one, in which the mechanical energy is directly converted and simultaneously stored as chemical energy without going through the intermediate step of first converting into electricity. By replacing the polyethylene (PE) separator as for conventional Li battery with a piezoelectric poly(vinylidene fluoride) (PVDF) film, the piezoelectric potential from the PVDF film as created by mechanical straining acts as a charge pump to drive Li ions to migrate from the cathode to the anode accompanying charging reactions at electrodes. This new approach can be applied to fabricating a self-charging power cell (SCPC) for sustainable driving micro/nanosystems and personal electronics.

Photocatalysis versus photosynthesis: A sensitivity analysis of devices for solar energy conversion and chemical transformations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osterloh, Frank E.

Here, the chemical literature often does not differentiate between photocatalytic (PC) and photosynthetic (PS) processes (including artificial photosynthesis) even though these reactions differ in their thermodynamics. Photocatalytic processes are thermodynamically downhill (ΔG < 0) and are merely accelerated by the catalyst, whereas photosynthetic processes are thermodynamically unfavorable (ΔG > 0) and require photochemical energy input to occur. Here we apply this differentiation to analyze the basic functions of PC and PS devices and to formulate design criteria for improved performance. As will be shown, the corresponding devices exhibit distinctly different sensitivities to their functional parameters. For example, under conditions ofmore » optimal light absorption, carrier lifetimes, and electrochemical rates, the performance of PCs is limited only by their surface area, while type 1 PS devices are limited by their carrier mobility and mass transport, and type 2 PS devices are limited by electrochemical charge-transfer selectivity. Strategies for the optimization of type 1 and 2 photosynthetic devices and photocatalysts are also discussed.« less

Combined Chemical Activation and Fenton Degradation to Convert Waste Polyethylene into High-Value Fine Chemicals.

PubMed

Chow, Cheuk-Fai; Wong, Wing-Leung; Ho, Keith Yat-Fung; Chan, Chung-Sum; Gong, Cheng-Bin

2016-07-04

Plastic waste is a valuable organic resource. However, proper technologies to recover usable materials from plastic are still very rare. Although the conversion/cracking/degradation of certain plastics into chemicals has drawn much attention, effective and selective cracking of the major waste plastic polyethylene is extremely difficult, with degradation of C-C/C-H bonds identified as the bottleneck. Pyrolysis, for example, is a nonselective degradation method used to crack plastics, but it requires a very high energy input. To solve the current plastic pollution crisis, more effective technologies are needed for converting plastic waste into useful substances that can be fed into the energy cycle or used to produce fine chemicals for industry. In this study, we demonstrate a new and effective chemical approach by using the Fenton reaction to convert polyethylene plastic waste into carboxylic acids under ambient conditions. Understanding the fundamentals of this new chemical process provides a possible protocol to solve global plastic-waste problems. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Waste paper for recycling: Overview and identification of potentially critical substances.

PubMed

Pivnenko, Kostyantyn; Eriksson, Eva; Astrup, Thomas F

2015-11-01

Paper product manufacturing involves a variety of chemicals used either directly in paper and pulp production or in the conversion processes (i.e. printing, gluing) that follow. Due to economic and environmental initiatives, paper recycling rates continue to rise. In Europe, recycling has increased by nearly 20% within the last decade or so, reaching a level of almost 72% in 2012. With increasing recycling rates, lower quality paper fractions may be included. This may potentially lead to accumulation or un-intended spreading of chemical substances contained in paper, e.g. by introducing chemicals contained in waste paper into the recycling loop. This study provides an overview of chemicals potentially present in paper and applies a sequential hazard screening procedure based on the intrinsic hazard, physical-chemical and biodegradability characteristics of the substances. Based on the results, 51 substances were identified as potentially critical (selected mineral oils, phthalates, phenols, parabens, as well as other groups of chemicals) in relation to paper recycling. It is recommended that these substances receive more attention in waste paper. Copyright © 2015 Elsevier Ltd. All rights reserved.

Extracellular lignase: a key to enhanced cellulose utilization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hira, A.; Barnett, S.M.; Shieh, C.H.

1978-01-01

An alternate approach to the conventional chemical processing of lignin, a potential renewable resource, is enzymic conversion. Biodegradation of wood, a lignin-cellulose complex, is accomplished naturally by various enzymes of microbial origin. Extracellular lignases have been isolated from pure cultures of Polyporus versicolor, Phanerochaete chrysosporium, and Pleurotus ostreatus. The isolated enzyme systems from these organisms have shown substrate specificity for guaiacol and hydroquinone and yielded a positive syringaldazine test. A commercial lignin was degraded by the enzyme system.

Tracking the Chemical and Structural Evolution of the TiS2 Electrode in the Lithium-Ion Cell Using Operando X-ray Absorption Spectroscopy.

PubMed

Zhang, Liang; Sun, Dan; Kang, Jun; Wang, Hsiao-Tsu; Hsieh, Shang-Hsien; Pong, Way-Faung; Bechtel, Hans A; Feng, Jun; Wang, Lin-Wang; Cairns, Elton J; Guo, Jinghua

2018-06-06

As the lightest and cheapest transition metal dichalcogenide, TiS 2 possesses great potential as an electrode material for lithium batteries due to the advantages of high energy density storage capability, fast ion diffusion rate, and low volume expansion. Despite the extensive investigation of its electrochemical properties, the fundamental discharge-charge reaction mechanism of the TiS 2 electrode is still elusive. Here, by a combination of ex situ and operando X-ray absorption spectroscopy with density functional theory calculations, we have clearly elucidated the evolution of the structural and chemical properties of TiS 2 during the discharge-charge processes. The lithium intercalation reaction is highly reversible and both Ti and sulfur are involved in the redox reaction during the discharge and charge processes. In contrast, the conversion reaction of TiS 2 is partially reversible in the first cycle. However, Ti-O related compounds are developed during electrochemical cycling over extended cycles, which results in the decrease of the conversion reaction reversibility and the rapid capacity fading. In addition, the solid electrolyte interphase formed on the electrode surface is found to be highly dynamic in the initial cycles and then gradually becomes more stable upon further cycling. Such understanding is important for the future design and optimization of TiS 2 based electrodes for lithium batteries.

In Vitro Corrosion and Cytocompatibility of ZK60 Magnesium Alloy Coated with Hydroxyapatite by a Simple Chemical Conversion Process for Orthopedic Applications

PubMed Central

Wang, Bing; Huang, Ping; Ou, Caiwen; Li, Kaikai; Yan, Biao; Lu, Wei

2013-01-01

Magnesium and its alloys—a new class of degradable metallic biomaterials—are being increasingly investigated as a promising alternative for medical implant and device applications due to their advantageous mechanical and biological properties. However, the high corrosion rate in physiological environments prevents the clinical application of Mg-based materials. Therefore, the objective of this study was to develop a hydroxyapatite (HA) coating on ZK60 magnesium alloy substrates to mediate the rapid degradation of Mg while improving its cytocompatibility for orthopedic applications. A simple chemical conversion process was applied to prepare HA coating on ZK60 magnesium alloy. Surface morphology, elemental compositions, and crystal structures were characterized using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction, respectively. The corrosion properties of samples were investigated by immersion test and electrochemical test. Murine fibroblast L-929 cells were harvested and cultured with coated and non-coated ZK60 samples to determine cytocompatibility. The degradation results suggested that the HA coatings decreased the degradation of ZK60 alloy. No significant deterioration in compression strength was observed for all the uncoated and coated samples after 2 and 4 weeks’ immersion in simulated body fluid (SBF). Cytotoxicity test indicated that the coatings, especially HA coating, improved cytocompatibility of ZK60 alloy for L929 cells. PMID:24300096

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lutwack, R.

The goal of the Silicon Material Task, a part of the FSA Project, was to develop and demonstrate the technology for the low-cost production of silicon of suitable purity to be used as the basic material for the manufacture of terrestrial photovoltaic solar cells. To be compatible with the price goals of the FSA Project, the price of the produced silicon was to be less than $10/kg (in 1975 dollars). Summarized in this document are 11 different processes for the production of silicon that were investigated and developed to varying extent by industrial, university, and government researchers. The silane-production sectionmore » of the Union Carbide Corp. (UCC) silane process was developed completely in this program. Coupled with Siemens-type chemical vapor deposition reactors, the process was carried through the pilot plant stage. The overall UCC process involves the conversion of metallurgical-grade silicon to silane followed by decomposition of the silane to purified silicon. Production of very high-purity silane and silicon was demonstrated. Although it has as yet not achieved commercial application, the development of fluidized-bed technology for the low-cost, high-throughput conversion of silane-to-silicon has been demonstrated in the research laboratory and now is in engineering development.« less

Co-cracking of real MSW into bio-oil over natural kaolin

NASA Astrophysics Data System (ADS)

Gandidi, I. M.; Susila, M. D.; Pambudi, N. A.

2017-03-01

Municipal solid waste (MSW) is a potential material that can be converted into bio-oil through thermal degradation process or pyrolysis. The efficiency and productivity of pyrolysis can be increased with the use of natural catalyst like kaolin. The addition of catalyst also reduces the overall cost of conversion process. In this study conversion of MSW into Bio Fuel using Pyrolysis in the presence of of natural kaolin as catalyst has been investigated for 60 min at 400°C temperature. During the process 0.5 w/w catalyst to MSW ratio was maintained. Gas chromatography-mass spectrometry (GC-MS) was used to analyse the chemical composition of bio fuel. It is found that bio-oil production increases substantially with the use of catalyst. It is observed that the production of bio-oil is 23.6 % with the use of catalyst in process, which was only 15.2 % without the use of catalyst. The hydrocarbon range distribution of oil produced through pyrolysis reveals that gasoline and diesel fuel (C5-C20) are its main constituents. The functional group detected in bio-oil by GC-MS analysis is similar to that of diesel-48 in which paraffin and olefin are major mass species.

Thermodynamic analysis of tar reforming through auto-thermal reforming process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nurhadi, N., E-mail: nurhadi@tekmira.esdm.go.id; Diniyati, Dahlia; Efendi, M. Ade Andriansyah

2015-12-29

Fixed bed gasification is a simple and suitable technology for small scale power generation. One of the disadvantages of this technology is producing tar. So far, tar is not utilized yet and being waste that should be treated into a more useful product. This paper presents a thermodynamic analysis of tar conversion into gas producer through non-catalytic auto-thermal reforming technology. Tar was converted into components, C, H, O, N and S, and then reacted with oxidant such as mixture of air or pure oxygen. Thus, this reaction occurred auto-thermally and reached chemical equilibrium. The sensitivity analysis resulted that the mostmore » promising process performance occurred at flow rate of air was reached 43% of stoichiometry while temperature of process is 1100°C, the addition of pure oxygen is 40% and preheating of oxidant flow is 250°C. The yield of the most promising process performance between 11.15-11.17 kmol/h and cold gas efficiency was between 73.8-73.9%.The results of this study indicated that thermodynamically the conversion of tar into producer gas through non-catalytic auto-thermal reformingis more promising.« less

Energy recovery from thermal treatment of dewatered sludge in wastewater treatment plants.

PubMed

Yang, Qingfeng; Dussan, Karla; Monaghan, Rory F D; Zhan, Xinmin

Sewage sludge is a by-product generated from municipal wastewater treatment (WWT) processes. This study examines the conversion of sludge via energy recovery from gasification/combustion for thermal treatment of dewatered sludge. The present analysis is based on a chemical equilibrium model of thermal conversion of previously dewatered sludge with moisture content of 60-80%. Prior to combustion/gasification, sludge is dried to a moisture content of 25-55% by two processes: (1) heat recovered from syngas/flue gas cooling and (2) heat recovered from syngas combustion. The electricity recovered from the combined heat and power process can be reused in syngas cleaning and in the WWT plant. Gas temperature, total heat and electricity recoverable are evaluated using the model. Results show that generation of electricity from dewatered sludge with low moisture content (≤ 70%) is feasible within a self-sufficient sludge treatment process. Optimal conditions for gasification correspond to an equivalence ratio of 2.3 and dried sludge moisture content of 25%. Net electricity generated from syngas combustion can account for 0.071 kWh/m(3) of wastewater treated, which is up to 25.4-28.4% of the WWT plant's total energy consumption.

Augmented digestion of lignocellulose by steam explosion, acid and alkaline pretreatment methods: a review.

PubMed

Singh, Joginder; Suhag, Meenakshi; Dhaka, Anil

2015-03-06

Lignocellulosic materials can be explored as one of the sustainable substrates for bioethanol production through microbial intervention as they are abundant, cheap and renewable. But at the same time, their recalcitrant structure makes the conversion process more cumbersome owing to their chemical composition which adversely affects the efficiency of bioethanol production. Therefore, the technical approaches to overcome recalcitrance of biomass feedstock has been developed to remove the barriers with the help of pretreatment methods which make cellulose more accessible to the hydrolytic enzymes, secreted by the microorganisms, for its conversion to glucose. Pretreatment of lignocellulosic biomass in cost effective manner is a major challenge to bioethanol technology research and development. Hence, in this review, we have discussed various aspects of three commonly used pretreatment methods, viz., steam explosion, acid and alkaline, applied on various lignocellulosic biomasses to augment their digestibility alongwith the challenges associated with their processing. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluation of selected chemical processes for production of low-cost silicon, phases 1 and 2

NASA Technical Reports Server (NTRS)

Blocher, J. M.; Browning, M. F.

1978-01-01

A miniplant, consisting of a 5 cm-diameter fluidized-bed reactor and associated equipment was used to study the deposition parameters, temperature, reactant composition, seed particle size, bed depth, reactant throughput, and methods of reactant introduction. It was confirmed that the permissible range of fluidized-bed temperature was limited at the lower end by zinc condensation (918 C) and at higher temperatures by rapidly decreasing conversion efficiency. Use of a graded bed temperature was shown to increase the conversion efficiency over that obtained in an isothermal bed. Other aspects of the process such as the condensation and fused-salt electrolysis of the ZnCl2 by-product for recycle of zinc and chlorine were studied to provide information required for design of a 50 MT/year experimental facility. In view of the favorable technical and economic indications obtained, it was recommended that construction and operation of the 50 MT/year experimental facility be implemented.

Strategies for Efficient Charge Separation and Transfer in Artificial Photosynthesis of Solar Fuels.

PubMed

Xu, Yuxing; Li, Ailong; Yao, Tingting; Ma, Changtong; Zhang, Xianwen; Shah, Jafar Hussain; Han, Hongxian

2017-11-23

Converting sunlight to solar fuels by artificial photosynthesis is an innovative science and technology for renewable energy. Light harvesting, photogenerated charge separation and transfer (CST), and catalytic reactions are the three primary steps in the processes involved in the conversion of solar energy to chemical energy (SE-CE). Among the processes, CST is the key "energy pump and delivery" step in determining the overall solar-energy conversion efficiency. Efficient CST is always high priority in designing and assembling artificial photosynthesis systems for solar-fuel production. This Review not only introduces the fundamental strategies for CST but also the combinatory application of these strategies to five types of the most-investigated semiconductor-based artificial photosynthesis systems: particulate, Z-scheme, hybrid, photoelectrochemical, and photovoltaics-assisted systems. We show that artificial photosynthesis systems with high SE-CE efficiency can be rationally designed and constructed through combinatory application of these strategies, setting a promising blueprint for the future of solar fuels. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Halogen-Mediated Conversion of Hydrocarbons to Commodities.

PubMed

Lin, Ronghe; Amrute, Amol P; Pérez-Ramírez, Javier

2017-03-08

Halogen chemistry plays a central role in the industrial manufacture of various important chemicals, pharmaceuticals, and polymers. It involves the reaction of halogens or halides with hydrocarbons, leading to intermediate compounds which are readily converted to valuable commodities. These transformations, predominantly mediated by heterogeneous catalysts, have long been successfully applied in the production of polymers. Recent discoveries of abundant conventional and unconventional natural gas reserves have revitalized strong interest in these processes as the most cost-effective gas-to-liquid technologies. This review provides an in-depth analysis of the fundamental understanding and applied relevance of halogen chemistry in polymer industries (polyvinyl chloride, polyurethanes, and polycarbonates) and in the activation of light hydrocarbons. The reactions of particular interest include halogenation and oxyhalogenation of alkanes and alkenes, dehydrogenation of alkanes, conversion of alkyl halides, and oxidation of hydrogen halides, with emphasis on the catalyst, reactor, and process design. Perspectives on the challenges and directions for future development in this exciting field are provided.

Genetic manipulation of lignin reduces recalcitrance and improves ethanol production from switchgrass

PubMed Central

Fu, Chunxiang; Mielenz, Jonathan R.; Xiao, Xirong; Ge, Yaxin; Hamilton, Choo Y.; Rodriguez, Miguel; Chen, Fang; Foston, Marcus; Ragauskas, Arthur; Bouton, Joseph; Dixon, Richard A.; Wang, Zeng-Yu

2011-01-01

Switchgrass is a leading dedicated bioenergy feedstock in the United States because it is a native, high-yielding, perennial prairie grass with a broad cultivation range and low agronomic input requirements. Biomass conversion research has developed processes for production of ethanol and other biofuels, but they remain costly primarily because of the intrinsic recalcitrance of biomass. We show here that genetic modification of switchgrass can produce phenotypically normal plants that have reduced thermal-chemical (≤180 °C), enzymatic, and microbial recalcitrance. Down-regulation of the switchgrass caffeic acid O-methyltransferase gene decreases lignin content modestly, reduces the syringyl:guaiacyl lignin monomer ratio, improves forage quality, and, most importantly, increases the ethanol yield by up to 38% using conventional biomass fermentation processes. The down-regulated lines require less severe pretreatment and 300–400% lower cellulase dosages for equivalent product yields using simultaneous saccharification and fermentation with yeast. Furthermore, fermentation of diluted acid-pretreated transgenic switchgrass using Clostridium thermocellum with no added enzymes showed better product yields than obtained with unmodified switchgrass. Therefore, this apparent reduction in the recalcitrance of transgenic switchgrass has the potential to lower processing costs for biomass fermentation-derived fuels and chemicals significantly. Alternatively, such modified transgenic switchgrass lines should yield significantly more fermentation chemicals per hectare under identical process conditions. PMID:21321194

Effects of thermal processing and various chemical substances on formaldehyde and dimethylamine formation in squid Dosidicus gigas.

PubMed

Zhu, Junli; Li, Jianrong; Jia, Jia

2012-09-01

Trimethylamine oxide (TMAO) in squid is demethylated to dimethylamine (DMA) and formaldehyde (FA) during storage and processing. This study examined the effects of thermal processing and various chemical substances on FA and DMA formation in squid. The thermal conversion of TMAO was assessed by analysing four squid and four gadoid fish species, which revealed that FA, DMA and trimethylamine (TMA) were gradually produced in squid, whereas TMA increased and FA decreased in gadoid fish. A significant increase in both FA and DMA levels was observed in the supernatant of jumbo squid with increased heating temperature and extended heating time at pH 6-7. Ferrous chloride combined with cysteine and/or ascorbate had a significantly positive effect on FA formation in the heated supernatant of jumbo squid. No significant difference was observed in the levels of Cu and Fe in squid and gadoid fish. The capability of Fe(2+) to promote the formation of FA and DMA was not completely attributable to its reducing power in squid. Non-enzymatic decomposition of TMAO was a key pathway during the thermal processing of jumbo squid, and Fe(2+) was a crucial activator in the formation of FA and DMA. Copyright © 2012 Society of Chemical Industry.

Efficiency enhancement of silicon nanowire solar cells by using UV/Ozone treatments and micro-grid electrodes

NASA Astrophysics Data System (ADS)

Chen, Junyi; Subramani, Thiyagu; Sun, Yonglie; Jevasuwan, Wipakorn; Fukata, Naoki

2018-05-01

Silicon nanowire solar cells were fabricated by metal catalyzed electroless etching (MCEE) followed by thermal chemical vapor deposition (CVD). In this study, we investigated two effects, a UV/ozone treatment and the use of a micro-grid electrodes, to enhance light absorption and reduce the optic losses in the solar cell device. The UV/ozone treatment successfully improved the conversion efficiency. The micro-grid electrodes were then applied in solar cell devices subjected to a back surface field (BSF) treatment and rapid thermal annealing (RTA). These effects improved the conversion efficiency from 9.4% to 10.9%. Moreover, to reduce surface recombination and improve the continuity of front electrodes, we optimized the etching time of the MCEE process, giving a high efficiency of 12.3%.

Homogeneously catalysed conversion of aqueous formaldehyde to H2 and carbonate.

PubMed

Trincado, M; Sinha, Vivek; Rodriguez-Lugo, Rafael E; Pribanic, Bruno; de Bruin, Bas; Grützmacher, Hansjörg

2017-04-28

Small organic molecules provide a promising solution for the requirement to store large amounts of hydrogen in a future hydrogen-based energy system. Herein, we report that diolefin-ruthenium complexes containing the chemically and redox non-innocent ligand trop 2 dad catalyse the production of H 2 from formaldehyde and water in the presence of a base. The process involves the catalytic conversion to carbonate salt using aqueous solutions and is the fastest reported for acceptorless formalin dehydrogenation to date. A mechanism supported by density functional theory calculations postulates protonation of a ruthenium hydride to form a low-valent active species, the reversible uptake of dihydrogen by the ligand and active participation of both the ligand and the metal in substrate activation and dihydrogen bond formation.

A promptly approach from monosaccharides of biomass to oligosaccharides via sharp-quenching thermo conversion (SQTC).

PubMed

Liu, Xiao; Wei, Weiqi; Wu, Shubin; Lei, Ming; Liu, Ying

2018-06-01

In this study, a novel and facile approach of conversion monosaccharides (glucose and xylose) to oligosaccharides (Cello-oligosaccharides and Xylo-oligosaccharides) was demonstrated. The approach did not introduce any chemical reagent and the preparation process could be environmentally friendly. Identification and quantification by ion chromatography (IC) and high performance liquid chromatography (HPLC) showed that the yields of COS and XOS reached to 44.62% (38 s) and 47.09% (30 s) respectively at 500 °C reaction temperature coupled with sharp-quenching method. Structural characterization indicated that such oligosaccharides showed a degree of polymerization (DP) with 2-6, and the units mainly linked by β-(1 → 4)-glycosidic bond. Copyright © 2018 Elsevier Ltd. All rights reserved.

Converting Panax ginseng DNA and chemical fingerprints into two-dimensional barcode.

PubMed

Cai, Yong; Li, Peng; Li, Xi-Wen; Zhao, Jing; Chen, Hai; Yang, Qing; Hu, Hao

2017-07-01

In this study, we investigated how to convert the Panax ginseng DNA sequence code and chemical fingerprints into a two-dimensional code. In order to improve the compression efficiency, GATC2Bytes and digital merger compression algorithms are proposed. HPLC chemical fingerprint data of 10 groups of P. ginseng from Northeast China and the internal transcribed spacer 2 (ITS2) sequence code as the DNA sequence code were ready for conversion. In order to convert such data into a two-dimensional code, the following six steps were performed: First, the chemical fingerprint characteristic data sets were obtained through the inflection filtering algorithm. Second, precompression processing of such data sets is undertaken. Third, precompression processing was undertaken with the P. ginseng DNA (ITS2) sequence codes. Fourth, the precompressed chemical fingerprint data and the DNA (ITS2) sequence code were combined in accordance with the set data format. Such combined data can be compressed by Zlib, an open source data compression algorithm. Finally, the compressed data generated a two-dimensional code called a quick response code (QR code). Through the abovementioned converting process, it can be found that the number of bytes needed for storing P. ginseng chemical fingerprints and its DNA (ITS2) sequence code can be greatly reduced. After GTCA2Bytes algorithm processing, the ITS2 compression rate reaches 75% and the chemical fingerprint compression rate exceeds 99.65% via filtration and digital merger compression algorithm processing. Therefore, the overall compression ratio even exceeds 99.36%. The capacity of the formed QR code is around 0.5k, which can easily and successfully be read and identified by any smartphone. P. ginseng chemical fingerprints and its DNA (ITS2) sequence code can form a QR code after data processing, and therefore the QR code can be a perfect carrier of the authenticity and quality of P. ginseng information. This study provides a theoretical basis for the development of a quality traceability system of traditional Chinese medicine based on a two-dimensional code.

Chemical elimination of the harmful properties of asbestos from military facilities.

PubMed

Pawełczyk, Adam; Božek, František; Grabas, Kazimierz; Chęcmanowski, Jacek

2017-03-01

This work presents research on the neutralization of asbestos banned from military use and its conversion to usable products. The studies showed that asbestos can be decomposed by the use of phosphoric acid. The process proved very effective when the phosphoric acid concentration was 30%, the temperature was 90°C and the reaction time 60min. Contrary to the common asbestos treatment method that consists of landfilling, the proposed process ensures elimination of the harmful properties of this waste material and its transformation into inert substances. The obtained products include calcium phosphate, magnesium phosphate and silica. Chemical, microscopic and X-ray analyses proved that the products are free of harmful fibers and can be, in particular, utilized for fertilizers production. The obtained results may contribute to development of an asbestos utilization technique that fits well into the European waste policy, regulated by the EU waste management law. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Piancatelli reaction and its variants: recent applications to high added-value chemicals and biomass valorization.

PubMed

Verrier, Charlie; Moebs-Sanchez, Sylvie; Queneau, Yves; Popowycz, Florence

2018-01-31

The Piancatelli reaction, also called the Piancatelli rearrangement, consists in the direct conversion of furfuryl alcohols to cyclopentenone derivatives through a furan ring opening-electrocyclization process. Discovered in the late 70's, this reaction has been scarcely used for more than 40 years but recently has been the focus of particular interest from the scientific community and an increasing number of publications on the topic have emerged in the last few years. The first part of this review provides an overview of the recent achievements in classical Piancatelli reactions, discussing reaction conditions and catalytic systems, whereas the second part focuses on the variants recently developed, including the use of new nucleophiles in the process. Finally, the third part of this review deals with the recent application of this transformation to the production of commodity chemicals from renewable carbon feedstocks based on sugar-derived furanic platforms.

Effects of bioleaching on the mechanical and chemical properties of waste rocks

NASA Astrophysics Data System (ADS)

Yin, Sheng-Hua; Wu, Ai-Xiang; Wang, Shao-Yong; Ai, Chun-Ming

2012-01-01

Bioleaching processes cause dramatic changes in the mechanical and chemical properties of waste rocks, and play an important role in metal recovery and dump stability. This study focused on the characteristics of waste rocks subjected to bioleaching. A series of experiments were conducted to investigate the evolution of rock properties during the bioleaching process. Mechanical behaviors of the leached waste rocks, such as failure patterns, normal stress, shear strength, and cohesion were determined through mechanical tests. The results of SEM imaging show considerable differences in the surface morphology of leached rocks located at different parts of the dump. The mineralogical content of the leached rocks reflects the extent of dissolution and precipitation during bioleaching. The dump porosity and rock size change under the effect of dissolution, precipitation, and clay transportation. The particle size of the leached rocks decreased due to the loss of rock integrity and the conversion of dry precipitation into fine particles.

Chemical Stabilization of Perovskite Solar Cells with Functional Fulleropyrrolidines

PubMed Central

2017-01-01

While perovskite solar cells have invigorated the photovoltaic research community due to their excellent power conversion efficiencies (PCEs), these devices notably suffer from poor stability. To address this crucial issue, a solution-processable organic chemical inhibition layer (OCIL) was integrated into perovskite solar cells, resulting in improved device stability and a maximum PCE of 16.3%. Photoenhanced self-doping of the fulleropyrrolidine mixture in the interlayers afforded devices that were advantageously insensitive to OCIL thickness, ranging from 4 to 190 nm. X-ray photoelectron spectroscopy (XPS) indicated that the fulleropyrrolidine mixture improved device stability by stabilizing the metal electrode and trapping ionic defects (i.e., I–) that originate from the perovskite active layer. Moreover, degraded devices were rejuvenated by repeatedly peeling away and replacing the OCIL/Ag electrode, and this repeel and replace process resulted in further improvement to device stability with minimal variation of device efficiency. PMID:29532021

Chemical Stabilization of Perovskite Solar Cells with Functional Fulleropyrrolidines.

PubMed

Liu, Yao; Page, Zachariah A; Zhou, Dongming; Duzhko, Volodimyr V; Kittilstved, Kevin R; Emrick, Todd; Russell, Thomas P

2018-02-28

While perovskite solar cells have invigorated the photovoltaic research community due to their excellent power conversion efficiencies (PCEs), these devices notably suffer from poor stability. To address this crucial issue, a solution-processable organic chemical inhibition layer (OCIL) was integrated into perovskite solar cells, resulting in improved device stability and a maximum PCE of 16.3%. Photoenhanced self-doping of the fulleropyrrolidine mixture in the interlayers afforded devices that were advantageously insensitive to OCIL thickness, ranging from 4 to 190 nm. X-ray photoelectron spectroscopy (XPS) indicated that the fulleropyrrolidine mixture improved device stability by stabilizing the metal electrode and trapping ionic defects (i.e., I - ) that originate from the perovskite active layer. Moreover, degraded devices were rejuvenated by repeatedly peeling away and replacing the OCIL/Ag electrode, and this repeel and replace process resulted in further improvement to device stability with minimal variation of device efficiency.

Random-walk enzymes.

PubMed

Mak, Chi H; Pham, Phuong; Afif, Samir A; Goodman, Myron F

2015-09-01

Enzymes that rely on random walk to search for substrate targets in a heterogeneously dispersed medium can leave behind complex spatial profiles of their catalyzed conversions. The catalytic signatures of these random-walk enzymes are the result of two coupled stochastic processes: scanning and catalysis. Here we develop analytical models to understand the conversion profiles produced by these enzymes, comparing an intrusive model, in which scanning and catalysis are tightly coupled, against a loosely coupled passive model. Diagrammatic theory and path-integral solutions of these models revealed clearly distinct predictions. Comparison to experimental data from catalyzed deaminations deposited on single-stranded DNA by the enzyme activation-induced deoxycytidine deaminase (AID) demonstrates that catalysis and diffusion are strongly intertwined, where the chemical conversions give rise to new stochastic trajectories that were absent if the substrate DNA was homogeneous. The C→U deamination profiles in both analytical predictions and experiments exhibit a strong contextual dependence, where the conversion rate of each target site is strongly contingent on the identities of other surrounding targets, with the intrusive model showing an excellent fit to the data. These methods can be applied to deduce sequence-dependent catalytic signatures of other DNA modification enzymes, with potential applications to cancer, gene regulation, and epigenetics.

Random-walk enzymes

PubMed Central

Mak, Chi H.; Pham, Phuong; Afif, Samir A.; Goodman, Myron F.

2015-01-01

Enzymes that rely on random walk to search for substrate targets in a heterogeneously dispersed medium can leave behind complex spatial profiles of their catalyzed conversions. The catalytic signatures of these random-walk enzymes are the result of two coupled stochastic processes: scanning and catalysis. Here we develop analytical models to understand the conversion profiles produced by these enzymes, comparing an intrusive model, in which scanning and catalysis are tightly coupled, against a loosely coupled passive model. Diagrammatic theory and path-integral solutions of these models revealed clearly distinct predictions. Comparison to experimental data from catalyzed deaminations deposited on single-stranded DNA by the enzyme activation-induced deoxycytidine deaminase (AID) demonstrates that catalysis and diffusion are strongly intertwined, where the chemical conversions give rise to new stochastic trajectories that were absent if the substrate DNA was homogeneous. The C → U deamination profiles in both analytical predictions and experiments exhibit a strong contextual dependence, where the conversion rate of each target site is strongly contingent on the identities of other surrounding targets, with the intrusive model showing an excellent fit to the data. These methods can be applied to deduce sequence-dependent catalytic signatures of other DNA modification enzymes, with potential applications to cancer, gene regulation, and epigenetics. PMID:26465508

Random-walk enzymes

NASA Astrophysics Data System (ADS)

Mak, Chi H.; Pham, Phuong; Afif, Samir A.; Goodman, Myron F.

2015-09-01

Enzymes that rely on random walk to search for substrate targets in a heterogeneously dispersed medium can leave behind complex spatial profiles of their catalyzed conversions. The catalytic signatures of these random-walk enzymes are the result of two coupled stochastic processes: scanning and catalysis. Here we develop analytical models to understand the conversion profiles produced by these enzymes, comparing an intrusive model, in which scanning and catalysis are tightly coupled, against a loosely coupled passive model. Diagrammatic theory and path-integral solutions of these models revealed clearly distinct predictions. Comparison to experimental data from catalyzed deaminations deposited on single-stranded DNA by the enzyme activation-induced deoxycytidine deaminase (AID) demonstrates that catalysis and diffusion are strongly intertwined, where the chemical conversions give rise to new stochastic trajectories that were absent if the substrate DNA was homogeneous. The C →U deamination profiles in both analytical predictions and experiments exhibit a strong contextual dependence, where the conversion rate of each target site is strongly contingent on the identities of other surrounding targets, with the intrusive model showing an excellent fit to the data. These methods can be applied to deduce sequence-dependent catalytic signatures of other DNA modification enzymes, with potential applications to cancer, gene regulation, and epigenetics.

Electrochemically enhanced microbial CO conversion to volatile fatty acids using neutral red as an electron mediator.

PubMed

Im, Chae Ho; Kim, Changman; Song, Young Eun; Oh, Sang-Eun; Jeon, Byong-Hun; Kim, Jung Rae

2018-01-01

Conversion of C1 gas feedstock, including carbon monoxide (CO), into useful platform chemicals has attracted considerable interest in industrial biotechnology. Nevertheless, the low conversion yield and/or growth rate of CO-utilizing microbes make it difficult to develop a C1 gas biorefinery process. The Wood-Ljungdahl pathway which utilize CO is a pathway suffered from insufficient electron supply, in which the conversion can be increased further when an additional electron source like carbohydrate or hydrogen is provided. In this study, electrode-based electron transference using a bioelectrochemical system (BES) was examined to compensate for the insufficient reducing equivalent and increase the production of volatile fatty acids. The BES including neutral red (BES-NR), which facilitated electron transfer between bacteria and electrode, was compared with BES without neutral red and open circuit control. The coulombic efficiency based on the current input to the system and the electrons recovered into VFAs, was significantly higher in BES-NR than the control. These results suggest that the carbon electrode provides a platform to regulate the redox balance for improving the bioconversion of CO, and amending the conventional C1 gas fermentation. Copyright © 2017 Elsevier Ltd. All rights reserved.

An integrated biorefinery concept for conversion of sugar beet pulp into value-added chemicals and pharmaceutical intermediates.

PubMed

Cárdenas-Fernández, Max; Bawn, Maria; Hamley-Bennett, Charlotte; Bharat, Penumathsa K V; Subrizi, Fabiana; Suhaili, Nurashikin; Ward, David P; Bourdin, Sarah; Dalby, Paul A; Hailes, Helen C; Hewitson, Peter; Ignatova, Svetlana; Kontoravdi, Cleo; Leak, David J; Shah, Nilay; Sheppard, Tom D; Ward, John M; Lye, Gary J

2017-09-21

Over 8 million tonnes of sugar beet are grown annually in the UK. Sugar beet pulp (SBP) is the main by-product of sugar beet processing which is currently dried and sold as a low value animal feed. SBP is a rich source of carbohydrates, mainly in the form of cellulose and pectin, including d-glucose (Glu), l-arabinose (Ara) and d-galacturonic acid (GalAc). This work describes the technical feasibility of an integrated biorefinery concept for the fractionation of SBP and conversion of these monosaccharides into value-added products. SBP fractionation is initially carried out by steam explosion under mild conditions to yield soluble pectin and insoluble cellulose fractions. The cellulose is readily hydrolysed by cellulases to release Glu that can then be fermented by a commercial yeast strain to produce bioethanol at a high yield. The pectin fraction can be either fully hydrolysed, using physico-chemical methods, or selectively hydrolysed, using cloned arabinases and galacturonases, to yield Ara-rich and GalAc-rich streams. These monomers can be separated using either Centrifugal Partition Chromatography (CPC) or ultrafiltration into streams suitable for subsequent enzymatic upgrading. Building on our previous experience with transketolase (TK) and transaminase (TAm) enzymes, the conversion of Ara and GalAc into higher value products was explored. In particular the conversion of Ara into l-gluco-heptulose (GluHep), that has potential therapeutic applications in hypoglycaemia and cancer, using a mutant TK is described. Preliminary studies with TAm also suggest GluHep can be selectively aminated to the corresponding chiral aminopolyol. The current work is addressing the upgrading of the remaining SBP monomer, GalAc, and the modelling of the biorefinery concept to enable economic and Life Cycle Analysis (LCA).

Status of photoelectrochemical production of hydrogen and electrical energy

NASA Technical Reports Server (NTRS)

Byvik, C. E.; Walker, G. H.

1976-01-01

The efficiency for conversion of electromagnetic energy to chemical and electrical energy utilizing semiconductor single crystals as photoanodes in electrochemical cells was investigated. Efficiencies as high as 20 percent were achieved for the conversion of 330 nm radiation to chemical energy in the form of hydrogen by the photoelectrolysis of water in a SrTiO3 based cell. The SrTiO3 photoanodes were shown to be stable in 9.5 M NaOH solutions for periods up to 48 hours. Efficiencies of 9 percent were measured for the conversion of broadband visible radiation to hydrogen using n-type GaAs crystals as photoanodes. Crystals of GaAs coated with 500 nm of gold, silver, or tin for surface passivation show no significant change in efficiency. By suppressing the production of hydrogen in a CdSe-based photogalvanic cell, an efficiency of 9 percent was obtained in conversion of 633 nm light to electrical energy. A CdS-based photogalvanic cell produced a conversion efficiency of 5 percent for 500 nm radiation.

Heterogeneous chemical reactions: Preparation of monodisperse latexes

NASA Technical Reports Server (NTRS)

Vanderhoff, J. W.; Micale, F. J.; El-Aasser, M. S.; Sterk, A. A.; Bethke, G. W.

1977-01-01

It is demonstrated that a photoinitiated emulsion polymerization can be carried out to a significant conversion in a SPAR rocket prototype polymerization vessel within the six minutes allowed for the experiment. The percentage of conversion was determined by both dilatometry and gravimetric methods with good agreement. The experimental results lead to the following conclusions: (1) emulsion polymerizations can be carried out to conversions as high as 75%, using a stable micellized styrene-SLS system plus photoinitiator; (2) dilatometry can be used to accurately determine both the rate and conversion of polymerization; (3) thermal expansion due to the light source and heat of reaction is small and can be corrected for if necessary; (4) although seeded emulsion polymerizations are unfavorable in photoinitiation, as opposed to chemical initiation, polymerizations can be carried out to at least 15% conversion using 7940A seed particles, with 0.05% solids; and (5) photoinitiation should be used to initiate polymerization in the SPAR rocket experiments because of the mechanical simplicity of the experiment.

Impact of two different types of grassland-to-cropland-conversion on dynamics of soil organic matter mineralization and N2O emission

NASA Astrophysics Data System (ADS)

Roth, G.; Flessa, H.; Helfrich, M.; Well, R.

2012-04-01

Conversion of grassland to arable land often causes a decrease of soil organic matter stocks and it increases nitrate leaching and the emission of the greenhouse gases CO2 and N2O. Conversion methods which minimize the mechanical impact on the surface soil may reduce mineralization rates and greenhouse gas emissions. We determined the effect of two different types of grassland to maize conversion (a) plowing of the sward followed by seeding of maize and (b) chemical killing of the sward by glyphosate followed by direct seed of maize) on the mineralization of grassland derived organic matter, the release of nitrate and the emission of N2O. The field experiment was carried out at the research station Kleve which is located in North Rhine-Westphalia, Germany. A four times replicated plot experiment with the following treatments was set up in April 2010: (i) mechanical conversion of grassland to maize (ii) chemical conversion grassland to maize and (iii) continuous grassland as reference. Nitrogen fertilization was 137 kg N ha-1 for maize and 250 kg N ha-1 for grassland. Soil respiration and emission of N2O were measured weekly for one year using manual closed chambers and gas chromatography. Emission of CO2 from mineralization of grassland-derived organic matter was determined from the δ13C signature of soil respiration. Soil respiration was mainly fueled by mineralization of grassland-derived organic carbon. There was no effect of the type of grassland conversion on total mineralization of organic matter originating from grassland. Both grassland to maize conversion treatments exhibited very high soil nitrate concentrations one year after grassland conversion (about 250 kg NO3-N in 0 - 90 cm). Total N2O emission decreased in the order chemical conversion of grassland (25.5) > mechanical conversion of grassland (20.1) > permanent grassland (10.8). Emissions were highest after harvest of maize when soil moisture increased. The results show that both types of grassland-to-maize conversion resulted in a large surplus of soil nitrate which promotes nitrate leaching to the groundwater and indirect N2O emissions. In addition, it caused high direct N2O emissions. We found no evidence that grassland conversion without mechanical plowing is an option to reduce groundwater contamination and greenhouse gas emission to the atmosphere.

Anaerobic bioconversion of organic waste into biogas by hot water treatment at near-critical conditions: application in bioregenerative life support.

PubMed

Lissens, Geert; Verstraete, Willy; Albrecht, Tobias; Brunner, Gerd; Lasseur, Christophe

2003-01-01

The feasibility of nearly-complete conversion of lignocellulosic waste (70% food crops, 20% faecal matter and 10% green algae) into biogas was investigated in the context of a Life Support Project. The treatment comprised a series of processes, i.e. a mesophilic laboratory scale CSTR (continuously stirred tank reactor), an upflow biofilm reactor and a hydrothermolysis system in near-critical water. By the one-stage CSTR, a biogas yield of 75% with a specific biogas production of 0.37 l biogas g(-1) VSS (volatile suspended solids) added at a HRT (hydraulic retention time) of 20 d was obtained. Biogas yields further increased with 10-15% at HRT > 20 d, indicating the hydrolysis of lignocellulose to be the rate-limiting conversion step. The solids present in the CSTR-effluent were subsequently treated by hot water treatment (T approximately 310-350 degrees C, p approximately 240 bar), resulting in effective carbon liquefaction (50-60% without and 83% with carbon dioxide saturation) and complete hygienisation of the residue. Subsequent anaerobic digestion of the hydrolysate allowed further conversion of 48-60% on COD (chemical oxygen demand) basis. Thus, the total process yielded biogas corresponding with a COD conversion up to 90% of the original organic matter. It appears that mesophilic digestion in conjunction with hydrothermolysis at near-critical conditions offers interesting features for (nearly) complete, non-toxic and hygienic carbon and energy recovery from human waste in a bioregenerative life support context.

Hydrothermal reactions of agricultural and food processing wastes in sub- and supercritical water: a review of fundamentals, mechanisms, and state of research.

PubMed

Pavlovič, Irena; Knez, Željko; Škerget, Mojca

2013-08-28

Hydrothermal (HT) reactions of agricultural and food-processing waste have been proposed as an alternative to conventional waste treatment technologies due to allowing several improvements in terms of process performance and energy and economical advantages, especially due to their great ability to process high moisture content biomass waste without prior dewatering. Complex structures of wastes and unique properties of water at higher temperatures and pressures enable a variety of physical-chemical reactions and a wide spectra of products. This paper's aim is to give extensive information about the fundamentals and mechanisms of HT reactions and provide state of the research of agri-food waste HT conversion.

Perovskites in catalysis and electrocatalysis

NASA Astrophysics Data System (ADS)

Hwang, Jonathan; Rao, Reshma R.; Giordano, Livia; Katayama, Yu; Yu, Yang; Shao-Horn, Yang

2017-11-01

Catalysts for chemical and electrochemical reactions underpin many aspects of modern technology and industry, from energy storage and conversion to toxic emissions abatement to chemical and materials synthesis. This role necessitates the design of highly active, stable, yet earth-abundant heterogeneous catalysts. In this Review, we present the perovskite oxide family as a basis for developing such catalysts for (electro)chemical conversions spanning carbon, nitrogen, and oxygen chemistries. A framework for rationalizing activity trends and guiding perovskite oxide catalyst design is described, followed by illustrations of how a robust understanding of perovskite electronic structure provides fundamental insights into activity, stability, and mechanism in oxygen electrocatalysis. We conclude by outlining how these insights open experimental and computational opportunities to expand the compositional and chemical reaction space for next-generation perovskite catalysts.

Fabrication and processing of next-generation oxygen carrier materials for chemical looping combustion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nadarajah, Arunan

Among numerous methods of controlling the global warming effect, Chemical Looping Combustion is known to be the most viable option currently. A key factor to a successful chemical looping process is the presence of highly effective oxygen carriers that enable fuel combustion by going through oxidation and reduction in the presence of air and fuel respectively. In this study, CaMnO 3-δ was used as the base material and doped on the A-site (Sr or La) and B-site (Fe, Ti, Zn and Al) by 10 mol % of dopants. Solid state reaction followed by mechanical extrusion (optimized paste formula) was usedmore » as the preparation method A series of novel doped perovskite-type oxygen carrier particles (Ca xLa (Or Sa) 1-x Mn 1-yByO 3-δ (B-site = Fe, Ti, Al, or Zr)) were synthesized by the proposed extrusion formula. The produced samples were characterized with XRD, SEM, BET and TGA techniques. According to the results obtained from TGA analysis, the oxygen capacity of the samples ranged between 1.2 for CLMZ and 1.75 for CSMF. Reactivity and oxygen uncoupling behaviors of the prepared samples were also evaluated using a fluidized bed chemical looping reactor using methane as the fuel at four different temperatures (800, 850, 900, 950 °C). All of the oxygen carriers showed oxygen uncoupling behavior and they were able to capture and release oxygen. Mass-based conversion of the perovskites was calculated and temperature increase proved to increase the mass-based conversion rate in all of the samples under study. Gas yield was calculated at 950 °C as well, and results showed that CLMZ, CM and CSMF showed 100% gas yields and CLMF and CSMZ showed approximately 85% yield in fluidized bed reactor, which is a high and acceptable quantity. Based on extended reactor tests the modified calcium manganese perovskite structures (CSMF) can be a good candidate for future pilot tests.« less

Basic Energy Sciences Program Update

DOE Office of Scientific and Technical Information (OSTI.GOV)

None, None

2016-01-04

The U.S. Department of Energy’s (DOE) Office of Basic Energy Sciences (BES) supports fundamental research to understand, predict, and ultimately control matter and energy at the electronic, atomic, and molecular levels to provide the foundations for new energy technologies and to support DOE missions in energy, environment, and national security. The research disciplines covered by BES—condensed matter and materials physics, chemistry, geosciences, and aspects of physical biosciences— are those that discover new materials and design new chemical processes. These disciplines touch virtually every aspect of energy resources, production, conversion, transmission, storage, efficiency, and waste mitigation. BES also plans, constructs, andmore » operates world-class scientific user facilities that provide outstanding capabilities for imaging and spectroscopy, characterizing materials of all kinds ranging from hard metals to fragile biological samples, and studying the chemical transformation of matter. These facilities are used to correlate the microscopic structure of materials with their macroscopic properties and to study chemical processes. Such experiments provide critical insights to electronic, atomic, and molecular configurations, often at ultrasmall length and ultrafast time scales.« less

Unravelling the mysteries of sub-second biochemical processes using time-resolved mass spectrometry.

PubMed

Lento, Cristina; Wilson, Derek J

2017-05-21

Many important chemical and biochemical phenomena proceed on sub-second time scales before entering equilibrium. In this mini-review, we explore the history and recent advancements of time-resolved mass spectrometry (TRMS) for the characterization of millisecond time-scale chemical reactions and biochemical processes. TRMS allows for the simultaneous tracking of multiple reactants, intermediates and products with no chromophoric species required, high sensitivity and temporal resolution. The method has most recently been used for the characterization of several short-lived reaction intermediates in rapid chemical reactions. Most of the reactions that occur in living organisms are accelerated by enzymes, with pre-steady state kinetics only attainable using time-resolved methods. TRMS has been increasingly used to monitor the conversion of substrates to products and the resulting changes to the enzyme during catalytic turnover. Early events in protein folding systems have also been elucidated, along with the characterization of dynamics and transient secondary structures in intrinsically disordered proteins. In this review, we will highlight representative examples where TRMS has been applied to study these phenomena.

The electrochemical reduction processes of solid compounds in high temperature molten salts.

PubMed

Xiao, Wei; Wang, Dihua

2014-05-21

Solid electrode processes fall in the central focus of electrochemistry due to their broad-based applications in electrochemical energy storage/conversion devices, sensors and electrochemical preparation. The electrolytic production of metals, alloys, semiconductors and oxides via the electrochemical reduction of solid compounds (especially solid oxides) in high temperature molten salts has been well demonstrated to be an effective and environmentally friendly process for refractory metal extraction, functional materials preparation as well as spent fuel reprocessing. The (electro)chemical reduction of solid compounds under cathodic polarizations generally accompanies a variety of changes at the cathode/melt electrochemical interface which result in diverse electrolytic products with different compositions, morphologies and microstructures. This report summarizes various (electro)chemical reactions taking place at the compound cathode/melt interface during the electrochemical reduction of solid compounds in molten salts, which mainly include: (1) the direct electro-deoxidation of solid oxides; (2) the deposition of the active metal together with the electrochemical reduction of solid oxides; (3) the electro-inclusion of cations from molten salts; (4) the dissolution-electrodeposition process, and (5) the electron hopping process and carbon deposition with the utilization of carbon-based anodes. The implications of the forenamed cathodic reactions on the energy efficiency, chemical compositions and microstructures of the electrolytic products are also discussed. We hope that a comprehensive understanding of the cathodic processes during the electrochemical reduction of solid compounds in molten salts could form a basis for developing a clean, energy efficient and affordable production process for advanced/engineering materials.

Catalysis for biomass and CO2 use through solar energy: opening new scenarios for a sustainable and low-carbon chemical production.

PubMed

Lanzafame, Paola; Centi, Gabriele; Perathoner, Siglinda

2014-11-21

The use of biomass, bio-waste and CO2 derived raw materials, the latter synthesized using H2 produced using renewable energy sources, opens new scenarios to develop a sustainable and low carbon chemical production, particularly in regions such as Europe lacking in other resources. This tutorial review discusses first this new scenario with the aim to point out, between the different possible options, those more relevant to enable this new future scenario for the chemical production, commenting in particular the different drivers (economic, technological and strategic, environmental and sustainability and socio-political) which guide the selection. The case of the use of non-fossil fuel based raw materials for the sustainable production of light olefins is discussed in more detail, but the production of other olefins and polyolefins, of drop-in intermediates and other platform molecules are also analysed. The final part discusses the role of catalysis in establishing this new scenario, summarizing the development of catalysts with respect to industrial targets, for (i) the production of light olefins by catalytic dehydration of ethanol and by CO2 conversion via FTO process, (ii) the catalytic synthesis of butadiene from ethanol, butanol and butanediols, and (iii) the catalytic synthesis of HMF and its conversion to 2,5-FDCA, adipic acid, caprolactam and 1,6-hexanediol.

Oxidation and Hydration of U 3O 8 Materials Following Controlled Exposure to Temperature and Humidity

DOE PAGES

Tamasi, Alison L.; Boland, Kevin S.; Czerwinski, Kenneth; ...

2015-03-18

Chemical signatures correlated with uranium oxide processing are of interest to forensic science for inferring sample provenance. Identification of temporal changes in chemical structures of process uranium materials as a function of controlled temperatures and relative humidities may provide additional information regarding sample history. In our study, a high-purity α-U 3O 8 sample and three other uranium oxide samples synthesized from reaction routes used in nuclear conversion processes were stored under controlled conditions over 2–3.5 years, and powder X-ray diffraction analysis and X-ray absorption spectroscopy were employed to characterize chemical speciation. We measured signatures from the α-U 3O 8 samplemore » indicated that the material oxidized and hydrated after storage under high humidity conditions over time. Impurities, such as uranyl fluoride or schoepites, were initially detectable in the other uranium oxide samples. After storage under controlled conditions, the analyses of the samples revealed oxidation over time, although the signature of the uranyl fluoride impurity diminished. The presence of schoepite phases in older uranium oxide material is likely indicative of storage under high humidity and should be taken into account for assessing sample history. Finally, the absence of a signature from a chemical impurity, such as uranyl fluoride hydrate, in an older material may not preclude its presence at the initial time of production.« less

Oxidation and Hydration of U 3 O 8 Materials Following Controlled Exposure to Temperature and Humidity

DOE PAGES

Tamasi, Alison L.; Boland, Kevin S.; Czerwinski, Kenneth; ...

2015-03-18

Chemical signatures correlated with uranium oxide processing are of interest to forensic science for inferring sample provenance. Identification of temporal changes in chemical structures of process uranium materials as a function of controlled temperatures and relative humidities may provide additional information regarding sample history. In our study, a high-purity α-U 3O 8 sample and three other uranium oxide samples synthesized from reaction routes used in nuclear conversion processes were stored under controlled conditions over 2–3.5 years, and powder X-ray diffraction analysis and X-ray absorption spectroscopy were employed to characterize chemical speciation. We measured signatures from the α-U 3O 8 samplemore » indicated that the material oxidized and hydrated after storage under high humidity conditions over time. Impurities, such as uranyl fluoride or schoepites, were initially detectable in the other uranium oxide samples. After storage under controlled conditions, the analyses of the samples revealed oxidation over time, although the signature of the uranyl fluoride impurity diminished. The presence of schoepite phases in older uranium oxide material is likely indicative of storage under high humidity and should be taken into account for assessing sample history. Finally, the absence of a signature from a chemical impurity, such as uranyl fluoride hydrate, in an older material may not preclude its presence at the initial time of production. LA-UR-15-21495.« less

Symposium on the Physical Chemistry of Solar Energy Conversion, Indianapolis American Chemical Society Meetings, Fall 2013

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lian, Tianquan

2013-09-20

The Symposium on the Physical Chemistry of Solar Energy Conversion at the Fall ACS Meeting in Indianapolis, IN (Sept. 8-12) featured the following sessions (approx. 6 speakers per session): (1) Quantum Dots and Nanorods for Solar Energy Conversion (2 half-day sessions); (2) Artificial Photosynthesis: Water Oxidation; (3) Artificial Photosynthesis: Solar Fuels (2 half-day sessions); (4) Organic Solar Cells; (5) Novel Concepts for Solar Energy Conversion (2 half-day sessions); (6) Emerging Techniques for Solar Energy Conversion; (7) Interfacial Electron Transfer

Titanium composite conversion coating formation on CRS In the presence of Mo and Ni ions: Electrochemical and microstructure characterizations

NASA Astrophysics Data System (ADS)

Eivaz Mohammadloo, H.; Sarabi, A. A.

2016-11-01

There have been an increasing interest in finding a replacement for the chromating process due to environmental and health concerns. Hence, in this study Chrome-free chemical conversion coatings were deposited on the surface of cold-rolled steel (CRS) on the basis of Titanium (TiCC), Titanium-Nickel (TiNiCC) and titanium-molybdate (TiMoCC) based conversion coating solutions. The surface characterization was performed by field emission scanning electron microscope (FESEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and contact angle measuring device. Also, the corrosion behavior was assessed by the means of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. FESEM and AFM study show that the TiNiCC is denser and more uniform than that TiCC and TiMoCC since, TiMoCC conversion coating presents network feature, and there were abundant micro-cracks on the surface of the coating. XPS results confirmed the precipitation of Ti and Ni oxide/hydroxide, Mn dioxide/trioxide on the surface of different Ti-based conversion coatings. Electrochemical results revealed that all Ti-based conversion coatings have better anti-corrosion properties than bare CRS. Moreover, TiNiCC treatment inhibited the corrosion of CRS to a significant degree (polarization resistance (Rp) = 5510 Ω cm2) in comparison with TiCC (Rp = 2705 Ω cm2) and TiMoCC (Rp = 805 Ω cm2).

1983 AFOSR/AFRPL Chemical Rocket Research Meeting, Abstracts and Agenda. Includes: Abstracts on Advanced Diagnostics of Reacting Flow, 28 February - 3 March 1983, Lancaster, California.

DTIC Science & Technology

1983-02-01

blow-off stability and fractional conversion was evaluated for design of an experimental study of these phenomena. The apparatus designed will be...the development of an array of experimental methods and test strategies designed to unravel a complex process that is very difficult to observe directly...this effort of lead field theoretic analysis as a design basis has made that possible. The experimental phase of the effort has three major

Formation of dehydroalanine from mimosine and cysteine: artifacts in gas chromatography/mass spectrometry based metabolomics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Young-Mo; Metz, Thomas O.; Hu, Zeping

2011-08-15

Trimethylsilyation is a chemical derivatization procedure routinely applied in gas chromatography-mass spectrometry (GC-MS)-based metabolomics. In this report, through de novo structural elucidation and comparison with authentic standards, we demonstrate that mimosine can be completely converted into dehydroalanine and 3,4-dihydroxypyridine during the trimethylsilyating process. Similarly, dehydroalanine can be formed from derivatization of cysteine. This conversion is a potential interference in GC-MS-based global metabolomics, as well as in analysis of amino acids.

Comparison of light harmonic generation in Al and Ge consisted silicate materials

NASA Astrophysics Data System (ADS)

Smirnov, Vitaly A.; Vostrikova, Liubov I.

2018-04-01

The silicate materials are perspective for different areas of laser physics and photonics. In this paper the comparison of the nonlinear conversion with the generation of the light harmonic in Al- and Ge-containing silicate materials is presented. The peculiarities of the processes of the light harmonic generation in dependence on the concentrations of the chemical components are discussed and the influences of the additional small inclusion of the elements of fifth group and the rare-earth elements are estimated.

Production of hydrogen by electron transfer catalysis using conventional and photochemical means

NASA Technical Reports Server (NTRS)

Rillema, D. P.

1981-01-01

Alternate methods of generating hydrogen from the sulfuric acid thermal or electrochemical cycles are presented. A number of processes requiring chemical, electrochemical or photochemical methods are also presented. These include the design of potential photoelectrodes and photocatalytic membranes using Ru impregnated nafion tubing, and the design of experiments to study the catalyzed electrolytic formation of hydrogen and sulfuric acid from sulfur dioxide and water using quinones as catalysts. Experiments are carried out to determine the value of these approaches to energy conversion.

Tuning Chemical Potential Difference across Alternately Doped Graphene p-n Junctions for High-Efficiency Photodetection.

PubMed

Lin, Li; Xu, Xiang; Yin, Jianbo; Sun, Jingyu; Tan, Zhenjun; Koh, Ai Leen; Wang, Huan; Peng, Hailin; Chen, Yulin; Liu, Zhongfan

2016-07-13

Being atomically thin, graphene-based p-n junctions hold great promise for applications in ultrasmall high-efficiency photodetectors. It is well-known that the efficiency of such photodetectors can be improved by optimizing the chemical potential difference of the graphene p-n junction. However, to date, such tuning has been limited to a few hundred millielectronvolts. To improve this critical parameter, here we report that using a temperature-controlled chemical vapor deposition process, we successfully achieved modulation-doped growth of an alternately nitrogen- and boron-doped graphene p-n junction with a tunable chemical potential difference up to 1 eV. Furthermore, such p-n junction structure can be prepared on a large scale with stable, uniform, and substitutional doping and exhibits a single-crystalline nature. This work provides a feasible method for synthesizing low-cost, large-scale, high efficiency graphene p-n junctions, thus facilitating their applications in optoelectronic and energy conversion devices.

Dry fractionation process as an important step in current and future lignocellulose biorefineries: a review.

PubMed

Barakat, Abdellatif; de Vries, Hugo; Rouau, Xavier

2013-04-01

The use of lignocellulosic biomass is promising for biofuels and materials and new technologies for the conversion need to be developed. However, the inherent properties of native lignocellulosic materials make them resistant to enzymatic and chemical degradation. Lignocellulosic biomass requires being pretreated to change the physical and chemical properties of lignocellulosic matrix in order to increase cell wall polymers accessibility and bioavailability. Mechanical size reduction may be chemical free intensive operation thanks to decreasing particles size and cellulose crystallinity, and increasing accessible surface area. Changes in these parameters improve the digestibility and the bioconversion of lignocellulosic biomass. However, mechanical size reduction requires cost-effective approaches from an energy input point of view. Therefore, the energy consumption in relation to physicochemical properties of lignocellulosic biomass was discussed. Even more, chemical treatments combined with physicochemical size reduction approaches are proposed to reduce energy consumption in this review. Copyright © 2013 Elsevier Ltd. All rights reserved.

Biomass pyrolysis liquid to citric acid via 2-step bioconversion.

PubMed

Yang, Zhiguang; Bai, Zhihui; Sun, Hongyan; Yu, Zhisheng; Li, Xingxing; Guo, Yifei; Zhang, Hongxun

2014-12-31

The use of fossil carbon sources for fuels and petrochemicals has serious impacts on our environment and is unable to meet the demand in the future. A promising and sustainable alternative is to substitute fossil carbon sources with microbial cell factories converting lignocellulosic biomass into desirable value added products. However, such bioprocesses require tolerance to inhibitory compounds generated during pretreatment of biomass. In this study, the process of sequential two-step bio-conversion of biomass pyrolysis liquid containing levoglucosan (LG) to citric acid without chemical detoxification has been explored, which can greatly improve the utilization efficiency of lignocellulosic biomass. The sequential two-step bio-conversion of corn stover pyrolysis liquid to citric acid has been established. The first step conversion by Phanerochaete chrysosporium (P. chrysosporium) is desirable to decrease the content of other compounds except levoglucosan as a pretreatment for the second conversion. The remaining levoglucosan in solution was further converted into citric acid by Aspergillus niger (A. niger) CBX-209. Thus the conversion of cellulose to citric acid is completed by both pyrolysis and bio-conversion technology. Under experimental conditions, levoglucosan yield is 12% based on the feedstock and the citric acid yield can reach 82.1% based on the levoglucosan content in the pyrolysis liquid (namely 82.1 g of citric acid per 100 g of levoglucosan). The study shows that P. chrysosporium and A. niger have the potential to be used as production platforms for value-added products from pyrolyzed lignocellulosic biomass. Selected P. chrysosporium is able to decrease the content of other compounds except levoglucosan and levoglucosan can be further converted into citric acid in the residual liquids by A. niger. Thus the conversion of cellulose to citric acid is completed by both pyrolysis and bio-conversion technology.

Engineering a cyanobacterium as the catalyst for the photosynthetic conversion of CO2 to 1,2-propanediol.

PubMed

Li, Han; Liao, James C

2013-01-22

The modern society primarily relies on petroleum and natural gas for the production of fuels and chemicals. One of the major commodity chemicals 1,2-propanediol (1,2-PDO), which has an annual production of more than 0.5 million tons in the United States, is currently produced by chemical processes from petroleum derived propylene oxide, which is energy intensive and not sustainable. In this study, we sought to achieve photosynthetic production of 1,2-PDO from CO2 using a genetically engineered cyanobacterium Synechococcus elongatus PCC 7942. Compared to the previously reported biological 1,2-PDO production processes which used sugar or glycerol as the substrates, direct chemical production from CO2 in photosynthetic organisms recycles the atmospheric CO2 and will not compete with food crops for arable land. In this study, we reported photosynthetic production of 1,2-PDO from CO2 using a genetically engineered cyanobacterium Synechococcus elongatus PCC 7942. Introduction of the genes encoding methylglyoxal synthase (mgsA), glycerol dehydrogenase (gldA), and aldehyde reductase (yqhD) resulted in the production of ~22 mg/L 1,2-PDO from CO2. However, a comparable amount of the pathway intermediate acetol was also produced, especially during the stationary phase. The production of 1,2-PDO requires a robust input of reducing equivalents from cellular metabolism. To take advantage of cyanobacteria's NADPH pool, the synthetic pathway of 1,2-PDO was engineered to be NADPH-dependent by exploiting the NADPH-specific secondary alcohol dehydrogenases which have not been reported for 1,2-PDO production previously. This optimization strategy resulted in the production of ~150 mg/L 1,2-PDO and minimized the accumulation of the incomplete reduction product, acetol. This work demonstrated that cyanobacteria can be engineered as a catalyst for the photosynthetic conversion of CO2 to 1,2-PDO. This work also characterized two NADPH-dependent sADHs for their catalytic capacity in 1,2-PDO formation, and suggested that they may be useful tools for renewable production of reduced chemicals in photosynthetic organisms.

Thermochemical conversion of waste tyres-a review.

PubMed

Labaki, Madona; Jeguirim, Mejdi

2017-04-01

A review of the energy recovery from waste tyres is presented and focuses on the three thermochemical processes used to valorise waste tyres: pyrolysis, gasification, and combustion/incineration. After recalling the chemical composition of tyres, the thermogravimetric behaviours of tyres or their components under different atmospheres are described. Different kinetic studies on the thermochemical processes are treated. Then, the three processes were investigated, with a particular attention given to the gasification, due to the information unavailability on this process. Pyrolysis is a thermochemical conversion to produce a hydrocarbon rich gas mixture, condensable liquids or tars, and a carbon-rich solid residue. Gasification is a form of pyrolysis, carried out at higher temperatures and under given atmosphere (air, steam, oxygen, carbon dioxide, etc.) in order to yield mainly low molecular weight gaseous products. Combustion is a process that needs a fuel and an oxidizer with an ignition system to produce heat and/or steam. The effects of various process parameters such as temperature, heating rate, residence time, catalyst addition, etc. on the energy efficiency and the products yields and characteristics are mainly reviewed. These thermochemical processes are considered to be the more attractive and practicable methods for recovering energy and material from waste tyres. For the future, they are the main promising issue to treat and valorise used tyres. However, efforts should be done in developing more efficient technical systems.

SSTAC/ARTS review of the draft Integrated Technology Plan (ITP). Volume 3: Space power and thermal management

NASA Technical Reports Server (NTRS)

1991-01-01

Viewgraphs of briefings from the SSTAC/ARTS review of the draft integrated technology plan on thermal power and thermal management are presented. Topics covered include: space energy conversion research and technology; space photovoltaic energy conversion; chemical energy conversion and storage; thermal energy conversion; power management; thermal management; space nuclear power; high capacity power; surface power and thermal management; space platforms power and thermal management; and project SELENE.

SSTAC/ARTS review of the draft Integrated Technology Plan (ITP). Volume 3: Space power and thermal management

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

Viewgraphs of briefings from the SSTAC/ARTS review of the draft integrated technology plan on thermal power and thermal management are presented. Topics covered include: space energy conversion research and technology; space photovoltaic energy conversion; chemical energy conversion and storage; thermal energy conversion; power management; thermal management; space nuclear power; high capacity power; surface power and thermal management; space platforms power and thermal management; and project SELENE.

Study on Evaluation of Project Management Data for Decommissioning of Uranium Refining and Conversion Plant - 12234

DOE Office of Scientific and Technical Information (OSTI.GOV)

Usui, Hideo; Izumo, Sari; Tachibana, Mitsuo

Some of nuclear facilities that would no longer be required have been decommissioned in JAEA (Japan Atomic Energy Agency). A lot of nuclear facilities have to be decommissioned in JAEA in near future. To implement decommissioning of nuclear facilities, it was important to make a rational decommissioning plan. Therefore, project management data evaluation system for dismantling activities (PRODIA code) has been developed, and will be useful for making a detailed decommissioning plan for an object facility. Dismantling of dry conversion facility in the uranium refining and conversion plant (URCP) at Ningyo-toge began in 2008. During dismantling activities, project management datamore » such as manpower and amount of waste generation have been collected. Such collected project management data has been evaluated and used to establish a calculation formula to calculate manpower for dismantling equipment of chemical process and calculate manpower for using a green house (GH) which was a temporary structure for preventing the spread of contaminants during dismantling. In the calculation formula to calculate project management data related to dismantling of equipment, the relation of dismantling manpower to each piece of equipment was evaluated. Furthermore, the relation of dismantling manpower to each chemical process was evaluated. The results showed promise for evaluating dismantling manpower with respect to each chemical process. In the calculation formula to calculate project management data related to use of the GH, relations of GH installation manpower and removal manpower to GH footprint were evaluated. Furthermore, the calculation formula for secondary waste generation was established. In this study, project management data related to dismantling of equipment and use of the GH were evaluated and analyzed. The project management data, manpower for dismantling of equipment, manpower for installation and removal of GH, and secondary waste generation from GH were considered. Establishment of the calculation formula for dismantling of each kind of equipment makes it possible to evaluate manpower for dismantling the whole facility. However, it is not easy to prepare calculation formula for all kinds of equipment that exist in the facility. Therefore, a simpler evaluation method was considered to calculate manpower based on facility characteristics. The results showed promise for evaluating dismantling manpower with respect to each chemical process. For dismantling of contaminated equipment, a GH has been used for protection of the spread of contamination. The use of a GH increases manpower for installation and removal of GH etc. Moreover, structural materials of the GH such as plastic sheets, adhesive tape become a burnable secondary waste. To create an effective dismantling plan, it is necessary to carefully consider use of a GH preliminarily. Thus, an evaluation method of project management data such as manpower and secondary waste generation was considered. The results showed promise for evaluating project management data of GH by using established calculation formula. (authors)« less

Process Parameters for Successful Synthesis of Carbon Nanotubes by Chemical Vapor Deposition: Implications for Chemical Mechanisms and Life-cycle Assessment

NASA Astrophysics Data System (ADS)

Xue, Ke

Manufacturing of carbon nanotubes (CNTs) via chemical vapor deposition (CVD) calls for thermal treatment associated with gas-phase rearrangement and catalyst deposition to achieve high cost efficiency and limited influence on environmental impact. Taking advantage of higher degree of structure control and economical efficiency, catalytic chemical vapor deposition (CCVD) has currently become the most prevailing synthesis approach for the synthesis of large-scale pure CNTs in past years. Because the synthesis process of CNTs dominates the potential ecotoxic impacts, materials consumption, energy consumption and greenhouse gas emissions should be further limited to efficiently reduce life cycle ecotoxicity of carbon naotubes. However, efforts to reduce energy and material requirements in synthesis of CNTs by CCVD are hindered by a lack of mechanistic understanding. In this thesis, the effect of operating parameters, especially the temperature, carbon source concentration, and residence time on the synthesis were studied to improve the production efficiency in a different angle. Thus, implications on the choice of operating parameters could be provided to help the synthesis of carbon nanotubes. Here, we investigated the typical operating parameters in conditions that have yielded successful CNT production in the published academic literature of over seventy articles. The data were filtered by quality of the resultant product and deemed either "successful" or "unsuccessful" according to the authors. Furthermore, growth rate data were tabulated and used as performance metric for the process whenever possible. The data provided us an opportunity to prompt possible and common methods for practioners in the synthesis of CNTs and motivate routes to achieve energy and material minimization. The statistical analysis revealed that methane and ethylene often rely on thermal conversion process to form direct carbon precursor; further, methane and ethylene could not be the direct CNT precursors by themselves. Acetylene does not show an additional energy demand or thermal conversion in the synthesis, and it could be the direct CNT precursors by itself; or at least, it would be most easily to get access to carbon nanotube growth while minimizing synthesis temperature. In detail, methane employs more energy demand (Tavg=883°C) than ethylene (Tavg=766°C), which in turn demands more energy than acetylene (Tavg=710°C) to successfully synthesize carbon nanotubes. The distinction in energy demand could be the result of kinetic energy requirements by the thermal conversion process of methane and ethylene to form direct CNT precursors, and methane employs the highest activation demand among three hydrocarbons. Thus, these results support the hypothesis that methane and ethylene could be thermally converted to form acetylene before CNT incorporation. In addition, methane and ethylene show the demand for hydrogen in thermal conversion process before CNT incorporation; whereas, hydrogen does not contribute to the synthesis via acetylene before CNT incorporation, except the reduction of catalyst. At relatively low hydrogen concentration, this work suggests that hydrogen prompts growth of carbon nanotubes via methane and ethylene, probably by reducing the catalysts or participating thermal reactions. In addition, "polymerization-like formation mechanism" could be supported by the higher growth rate of CNTs via ethylene than acetylene. There could be an optimum residence time to maintain a relatively higher growth rate. At too low residence time, carbon source could not be accumulated, causing a waste of material; while too high residence time may cause the limitation of carbon source supplement and accumulation of byproducts. At last, high concentration of carbon source and hydrogen could cause more energy consumption, while it helps to achieve a high growth rate, due to the more presence of direct carbon precursor.

Double stratification effects in chemically reactive squeezed Sutterby fluid flow with thermal radiation and mixed convection

NASA Astrophysics Data System (ADS)

Ahmad, S.; Farooq, M.; Javed, M.; Anjum, Aisha

2018-03-01

A current analysis is carried out to study theoretically the mixed convection characteristics in squeezing flow of Sutterby fluid in squeezed channel. The constitutive equation of Sutterby model is utilized to characterize the rheology of squeezing phenomenon. Flow characteristics are explored with dual stratification. In flowing fluid which contains heat and mass transport, the first order chemical reaction and radiative heat flux affect the transport phenomenon. The systems of non-linear governing equations have been modulating which then solved by mean of convergent approach (Homotopy Analysis Method). The graphs are reported and illustrated for emerging parameters. Through graphical explanations, drag force, rate of heat and mass transport are conversed for different pertinent parameters. It is found that heat and mass transport rate decays with dominant double stratified parameters and chemical reaction parameter. The present two-dimensional examination is applicable in some of the engineering processes and industrial fluid mechanics.

Mechanistic Insights and Computational Design of Transition-Metal Catalysts for Hydrogenation and Dehydrogenation Reactions.

PubMed

Chen, Xiangyang; Yang, Xinzheng

2016-10-01

Catalytic hydrogenation and dehydrogenation reactions are fundamentally important in chemical synthesis and industrial processes, as well as potential applications in the storage and conversion of renewable energy. Modern computational quantum chemistry has already become a powerful tool in understanding the structures and properties of compounds and elucidating mechanistic insights of chemical reactions, and therefore, holds great promise in the design of new catalysts. Herein, we review our computational studies on the catalytic hydrogenation of carbon dioxide and small organic carbonyl compounds, and on the dehydrogenation of amine-borane and alcohols with an emphasis on elucidating reaction mechanisms and predicting new catalytic reactions, and in return provide some general ideas for the design of high-efficiency, low-cost transition-metal complexes for hydrogenation and dehydrogenation reactions. © 2016 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kinetic calorimetry in the study of the mechanism of low-temperature chemical reactions

NASA Astrophysics Data System (ADS)

Barkalov, I. M.; Kiryukhin, D. P.

Chemical reactions are always followed by a change in the reacting system enthalpy, hence, calorimetry as a method of enthalpy and heat capacity measuring is a universal and, sometimes, even the only possible way of studying chemical reaction kinetics. Throughout its long history, the calorimeter, having preserved the positions of the main method of thermodynamic studies, has conquered a new field of application: that of kinetic study of chemical reactions. The advantages and disadvantages of the kinetic calorimeter are now obvious. First, the advantages are: (1) the possibility of measuring the rate of a chemical reaction without any special requirements being imposed on the reaction medium (solid, viscous, multicomponent systems); (2) the high efficiency: a large volume of kinetic information in one experiment and a non-destructive character of changes; (3) the possibility of measuring directly in the field of ionizing radiation (γ-radiation, accelerated electrons) and light; and (4) recording of the chemical conversion directly at the time of its occurrence. The disadvantages of this method are: (1) the high inertia of standard calorimeter systems (τC⋍102-103S), which restricts the possibilities of studying fast processes; and (2) the complexity of the correct organization of the calorimeter experiment when the parameters of the process are changed (overheating in the sample, conversion of the process to explosive and auto wave regimens). One of the oldest and most universal methods of studying the mechanism of chemical reactions, calorimetry, is now passing through a period of turbulent development due to the advances in electronics and computerization. The wide variety of types of calorimeter set-ups and the large assortment of measurement schemes in the currently described methods complicate the experimental selection of the necessary instrument rather than facilitate it. The basic principles of the method, the types of calorimeters, and the measuring schemes are described [1-5]. However, despite the high working characteristics of modern calorimeters (Perkin-Elmer, Du Pont, LKB, etc.), all of them have one principal disadvantage: a cell with a sample is placed in them at room temperature. In cryochemical investigation, when the sample has metastable formations, the loading is made `from nitrogen to nitrogen', i.e. the sample prepared at 77 K should be loaded into a calorimeter at 77 K. Besides, the existing installations do not allow measurements at the temperatures <110K. For this reason, the Laboratory of Cryochemistry and Radiation Chemistry at the Institute of Chemical Physics in Chernogolovka has created original calorimetric techniques which allow: (1) the carrying out phase analysis and the determination of the main thermodynamic characteristic of individual substances and complicated systems in the temperature range 5 300 K. Sample loading can be conducted at 77 K that allows us to study the systems containing: tetrafiuoroethylene, hexafluoropropylene, ethylene, carbon monoxide, nitrogen, methane, hydrogen, oxygen, ozone, formaldehyde and many other gaseous substances; (2) the study of the dynamics of chemical reactions and to measure the main kinetic parameters of the processes-the elementary rate constants and the activation energies. The experiment can be conducted both under direct action of radiation and UV light and in the post-effect mode [5,6].