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.

Noncatalytic oxypyrolysis of C{sub 2+}-hydrocarbons from natural gas to ethylene and propylene in a most energy-efficient and safe manner

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

Choudhary, V.R.; Mulla, S.A.R.; Rajput, A.M.

1997-06-01

Noncatalytic oxypyrolysis of C{sub 2+}-hydrocarbons from natural gas at 700--850 C in the presence of steam and limited oxygen yields ethylene and propylene with appreciable conversion and high selectivity but with almost no coke or tarlike product formation. In this process, the exothermic oxidative hydrocarbon conversion reactions are coupled directly with the endothermic cracking of C{sub 2+}-hydrocarbons by their simultaneous occurrence. Hence, the process operates in a most energy-efficient and safe (or nonhazardous) manner and also can be made almost thermoneutral or mildly endothermic/exothermic, thus requiring little or no external energy for the hydrocarbon conversion reactions.

Heterogeneously Catalyzed Endothermic Fuel Cracking

DTIC Science & Technology

2016-08-28

Much of this literature is in the context of gas -to- liquids technology and industrial dehydrogenation processes. Based on the published measurements...certain zeolites. Comparisons of conversion, major product distributions and molecular weight growth processes in the gas -phase pyrolysis of model...thereby maximizing the extent of cooling, (b) increase catalyst activity for fuel decomposition, but inhibit gas -phase molecular weight growth

Influence of the Stefan Flow on Heat Transfer in the System "Gas-Solid Particle" in Thermochemical Conversion of a Solid Fuel

NASA Astrophysics Data System (ADS)

Pechenegov, Yu. Ya.; Mrakin, A. N.

2017-09-01

Recommendations are presented on calculating interphase heat transfer in gas-disperse systems of plants for thermochemical conversion of ground solid fuel. An analysis is made of the influence of the gas release of fuel particles on the heat transfer during their heating. It is shown that in the processes of thermal treatment of oil shales, the presence of gas release reduces substantially the intensity of interphase heat transfer compared to the heat transfer in the absence of thermochemical decomposition of the solid phase.

LanzaTech- Capturing Carbon. Fueling Growth.

ScienceCinema

NONE

2018-01-16

LanzaTech will design a gas fermentation system that will significantly improve the rate at which methane gas is delivered to a biocatalyst. Current gas fermentation processes are not cost effective compared to other gas-to-liquid technologies because they are too slow for large-scale production. If successful, LanzaTech's system will process large amounts of methane at a high rate, reducing the energy inputs and costs associated with methane conversion.

Hydraulic and Mechanical Effects from Gas Hydrate Conversion and Secondary Gas Hydrate Formation during Injection of CO2 into CH4-Hydrate-Bearing Sediments

NASA Astrophysics Data System (ADS)

Bigalke, N.; Deusner, C.; Kossel, E.; Schicks, J. M.; Spangenberg, E.; Priegnitz, M.; Heeschen, K. U.; Abendroth, S.; Thaler, J.; Haeckel, M.

2014-12-01

The injection of CO2 into CH4-hydrate-bearing sediments has the potential to drive natural gas production and simultaneously sequester CO2 by hydrate conversion. The process aims at maintaining the in situ hydrate saturation and structure and causing limited impact on soil hydraulic properties and geomechanical stability. However, to increase hydrate conversion yields and rates it must potentially be assisted by thermal stimulation or depressurization. Further, secondary formation of CO2-rich hydrates from pore water and injected CO2 enhances hydrate conversion and CH4 production yields [1]. Technical stimulation and secondary hydrate formation add significant complexity to the bulk conversion process resulting in spatial and temporal effects on hydraulic and geomechanical properties that cannot be predicted by current reservoir simulation codes. In a combined experimental and numerical approach, it is our objective to elucidate both hydraulic and mechanical effects of CO2 injection and CH4-CO2-hydrate conversion in CH4-hydrate bearing soils. For the experimental approach we used various high-pressure flow-through systems equipped with different online and in situ monitoring tools (e.g. Raman microscopy, MRI and ERT). One particular focus was the design of triaxial cell experimental systems, which enable us to study sample behavior even during large deformations and particle flow. We present results from various flow-through high-pressure experimental studies on different scales, which indicate that hydraulic and geomechanical properties of hydrate-bearing sediments are drastically altered during and after injection of CO2. We discuss the results in light of the competing processes of hydrate dissociation, hydrate conversion and secondary hydrate formation. Our results will also contribute to the understanding of effects of temperature and pressure changes leading to dissociation of gas hydrates in ocean and permafrost systems. [1] Deusner C, Bigalke N, Kossel E, Haeckel M. Methane Production from Gas Hydrate Deposits through Injection of Supercritical CO2. Energies 2012:5(7): 2112-2140.

Development of a Hydrogasification Process for Co-Production of Substitute Natural Gas (SNG) and Electric Power from Western Coals-Phase I

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

Raymond Hobbs

2007-05-31

The Advanced Hydrogasification Process (AHP)--conversion of coal to methane--is being developed through NETL with a DOE Grant and has successfully completed its first phase of development. The results so far are encouraging and have led to commitment by DOE/NETL to begin a second phase--bench scale reactor vessel testing, expanded engineering analysis and economic perspective review. During the next decade new means of generating electricity, and other forms of energy, will be introduced. The members of the AHP Team envision a need for expanded sources of natural gas or substitutes for natural gas, to fuel power generating plants. The initial workmore » the team has completed on a process to use hydrogen to convert coal to methane (pipeline ready gas) shows promising potential. The Team has intentionally slanted its efforts toward the needs of US electric utilities, particularly on fuels that can be used near urban centers where the greatest need for new electric generation is found. The process, as it has evolved, would produce methane from coal by adding hydrogen. The process appears to be efficient using western coals for conversion to a highly sought after fuel with significantly reduced CO{sub 2} emissions. Utilities have a natural interest in the preservation of their industry, which will require a dramatic reduction in stack emissions and an increase in sustainable technologies. Utilities tend to rank long-term stable supplies of fuel higher than most industries and are willing to trade some ratio of cost for stability. The need for sustainability, stability and environmentally compatible production are key drivers in the formation and progression of the AHP development. In Phase II, the team will add a focus on water conservation to determine how the basic gasification process can be best integrated with all the plant components to minimize water consumption during SNG production. The process allows for several CO{sub 2} reduction options including consumption of the CO{sub 2} in the original process as converted to methane. The process could under another option avoid emissions following the conversion to SNG through an adjunct algae conversion process. The algae would then be converted to fuels or other products. An additional application of the algae process at the end use natural gas fired plant could further reduce emissions. The APS team fully recognizes the competition facing the process from natural gas and imported liquid natural gas. While we expect those resources to set the price for methane in the near-term, the team's work to date indicates that the AHP process can be commercially competitive, with the added benefit of assuring long-term energy supplies from North American resources. Conversion of coal to a more readily transportable fuel that can be employed near load centers with an overall reduction of greenhouses gases is edging closer to reality.« less

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.

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

NONE

The original concept envisioned for the use of Fischer-Tropsch processing (FTP) of United States associated natural gas in this study was to provide a way of utilizing gas which could not be brought to market because a pipeline was not available or for which there was no local use. Conversion of gas by FTP could provide a means of utilizing offshore associated gas which would not require installation of a pipeline or re-injection. The premium quality F-T hydrocarbons produced by conversion of the gas can be transported in the same way as the crude oil or in combination (blended) withmore » it, eliminating the need for a separate gas transport system. FTP will produce a synthetic crude oil, thus increasing the effective size of the resource. The two conventional approaches currently used in US territory for handling of natural gas associated with crude petroleum production are re-injection and pipelining. Conversion of natural gas to a liquid product which can be transported to shore by tanker can be accomplished by FTP to produce hydrocarbons, or by conversion to chemical products such as methanol or ammonia, or by cryogenic liquefaction (LNG). This study considers FTP and briefly compares it to methanol and LNG. The Energy International Corporation cobalt catalyst, ratio adjusted, slurry bubble column F-T process was used as the basis for the study and the comparisons. An offshore F-T plant can best be accommodated by an FPSO (Floating Production, Storage, Offloading vessel) based on a converted surplus tanker, such as have been frequently used around the world recently. Other structure types used in deep water (platforms) are more expensive and cannot handle the required load.« less

Synthesis gas production by mixed conducting membranes with integrated conversion into liquid products

DOEpatents

Nataraj, Shankar; Russek, Steven Lee; Dyer, Paul Nigel

2000-01-01

Natural gas or other methane-containing feed gas is converted to a C.sub.5 -C.sub.19 hydrocarbon liquid in an integrated system comprising an oxygenative synthesis gas generator, a non-oxygenative synthesis gas generator, and a hydrocarbon synthesis process such as the Fischer-Tropsch process. The oxygenative synthesis gas generator is a mixed conducting membrane reactor system and the non-oxygenative synthesis gas generator is preferably a heat exchange reformer wherein heat is provided by hot synthesis gas product from the mixed conducting membrane reactor system. Offgas and water from the Fischer-Tropsch process can be recycled to the synthesis gas generation system individually or in combination.

Tunable molten oxide pool assisted plasma-melter vitrification systems

DOEpatents

Titus, Charles H.; Cohn, Daniel R.; Surma, Jeffrey E.

1998-01-01

The present invention provides tunable waste conversion systems and apparatus which have the advantage of highly robust operation and which provide complete or substantially complete conversion of a wide range of waste streams into useful gas and a stable, nonleachable solid product at a single location with greatly reduced air pollution to meet air quality standards. The systems provide the capability for highly efficient conversion of waste into high quality combustible gas and for high efficiency conversion of the gas into electricity by utilizing a high efficiency gas turbine or an internal combustion engine. The solid product can be suitable for various commercial applications. Alternatively, the solid product stream, which is a safe, stable material, may be disposed of without special considerations as hazardous material. In the preferred embodiment, the arc plasma furnace and joule heated melter are formed as a fully integrated unit with a common melt pool having circuit arrangements for the simultaneous independently controllable operation of both the arc plasma and the joule heated portions of the unit without interference with one another. The preferred configuration of this embodiment of the invention utilizes two arc plasma electrodes with an elongated chamber for the molten pool such that the molten pool is capable of providing conducting paths between electrodes. The apparatus may additionally be employed with reduced use or without further use of the gases generated by the conversion process. The apparatus may be employed as a net energy or net electricity producing unit where use of an auxiliary fuel provides the required level of electricity production. Methods and apparatus for converting metals, non-glass forming waste streams and low-ash producing inorganics into a useful gas are also provided. The methods and apparatus for such conversion include the use of a molten oxide pool having predetermined electrical, thermal and physical characteristics capable of maintaining optimal joule heating and glass forming properties during the conversion process.

Catalyst and process development for synthesis gas conversion to isobutylene. Final report, September 1, 1990--January 31, 1994

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

Anthony, R.G.; Akgerman, A.

1994-05-06

Previous work on isosynthesis (conversion of synthesis gas to isobutane and isobutylene) was performed at very low conversions or extreme process conditions. The objectives of this research were (1) determine the optimum process conditions for isosynthesis; (2) determine the optimum catalyst preparation method and catalyst composition/properties for isosynthesis; (3) determine the kinetics for the best catalyst; (4) develop reactor models for trickle bed, slurry, and fixed bed reactors; and (5) simulate the performance of fixed bed trickle flow reactors, slurry flow reactors, and fixed bed gas phase reactors for isosynthesis. More improvement in catalyst activity and selectivity is needed beforemore » isosynthesis can become a commercially feasible (stand-alone) process. Catalysts prepared by the precipitation method show the most promise for future development as compared with those prepared hydrothermally, by calcining zirconyl nitrate, or by a modified sol-gel method. For current catalysts the high temperatures (>673 K) required for activity also cause the production of methane (because of thermodynamics). A catalyst with higher activity at lower temperatures would magnify the unique selectivity of zirconia for isobutylene. Perhaps with a more active catalyst and acidification, oxygenate production could be limited at lower temperatures. Pressures above 50 atm cause an undesirable shift in product distribution toward heavier hydrocarbons. A model was developed that can predict carbon monoxide conversion an product distribution. The rate equation for carbon monoxide conversion contains only a rate constant and an adsorption equilibrium constant. The product distribution was predicted using a simple ratio of the rate of CO conversion. This report is divided into Introduction, Experimental, and Results and Discussion sections.« less

Scientific bases of biomass processing into basic component of aviation fuel

NASA Astrophysics Data System (ADS)

Kachalov, V. V.; Lavrenov, V. A.; Lishchiner, I. I.; Malova, O. V.; Tarasov, A. L.; Zaichenko, V. M.

2016-11-01

A combination of feedstock pyrolysis and the cracking of the volatile pyrolysis products on the charcoal at 1000 °C allows to obtain a tarless synthesis gas which contains 90 vol% or more of carbon monoxide and hydrogen in approximately equal proportions. Basic component of aviation fuel was synthesized in a two-stage process from gas obtained by pyrolytic processing of biomass. Methanol and dimethyl ether can be efficiently produced in a two-layer loading of methanolic catalyst and γ-Al2O3. The total conversion of CO per pass was 38.2% using for the synthesis of oxygenates a synthesis gas with adverse ratio of H2/CO = 0.96. Conversion of CO to CH3OH was 15.3% and the conversion of CO to dimethyl ether was 20.9%. A high yield of basic component per oxygenates mass (44.6%) was obtained during conversion. The high selectivity of the synthesis process for liquid hydrocarbons was observed. An optimal recipe of aviation fuel B-92 based on a synthesized basic component was developed. The prototype of aviation fuel meets the requirements for B-92 when straight fractions of 50-100 °C (up to 35 wt%), isooctane (up to 10 wt%) and ethyl fluid (2.0 g/kg calculated as tetraethyl lead) is added to the basic component.

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

Lebarbier Dagel, Vanessa M.; Li, J.; Taylor, Charles E.

This collaborative joint research project is in the area of advanced gasification and conversion, within the Chinese Academy of Sciences (CAS)-National Energy Technology Laboratory (NETL)-Pacific Northwest National Laboratory (PNNL) Memorandum of Understanding. The goal for this subtask is the development of advanced syngas conversion technologies. Two areas of investigation were evaluated: Sorption-Enhanced Synthetic Natural Gas Production from Syngas The conversion of synthetic gas (syngas) to synthetic natural gas (SNG) is typically catalyzed by nickel catalysts performed at moderate temperatures (275 to 325°C). The reaction is highly exothermic and substantial heat is liberated, which can lead to process thermal imbalance andmore » destruction of the catalyst. As a result, conversion per pass is typically limited, and substantial syngas recycle is employed. Commercial methanation catalysts and processes have been developed by Haldor Topsoe, and in some reports, they have indicated that there is a need and opportunity for thermally more robust methanation catalysts to allow for higher per-pass conversion in methanation units. SNG process requires the syngas feed with a higher H2/CO ratio than typically produced from gasification processes. Therefore, the water-gas shift reaction (WGS) will be required to tailor the H2/CO ratio. Integration with CO2 separation could potentially eliminate the need for a separate WGS unit, thereby integrating WGS, methanation, and CO2 capture into one single unit operation and, consequently, leading to improved process efficiency. The SNG process also has the benefit of producing a product stream with high CO2 concentrations, which makes CO2 separation more readily achievable. The use of either adsorbents or membranes that selectively separate the CO2 from the H2 and CO would shift the methanation reaction (by driving WGS for hydrogen production) and greatly improve the overall efficiency and economics of the process. The scope of this activity was to develop methods and enabling materials for syngas conversion to SNG with readily CO2 separation. Suitable methanation catalyst and CO2 sorbent materials were developed. Successful proof-of-concept for the combined reaction-sorption process was demonstrated, which culminated in a research publication. With successful demonstration, a decision was made to switch focus to an area of fuels research of more interest to all three research institutions (CAS-NETL-PNNL). Syngas-to-Hydrocarbon Fuels through Higher Alcohol Intermediates There are two types of processes in syngas conversion to fuels that are attracting R&D interest: 1) syngas conversion to mixed alcohols; and 2) syngas conversion to gasoline via the methanol-to-gasoline process developed by Exxon-Mobil in the 1970s. The focus of this task was to develop a one-step conversion technology by effectively incorporating both processes, which is expected to reduce the capital and operational cost associated with the conversion of coal-derived syngas to liquid fuels. It should be noted that this work did not further study the classic Fischer-Tropsch reaction pathway. Rather, we focused on the studies for unique catalyst pathways that involve the direct liquid fuel synthesis enabled by oxygenated intermediates. Recent advances made in the area of higher alcohol synthesis including the novel catalytic composite materials recently developed by CAS using base metal catalysts were used.« less

Numerical modelling of biomass combustion: Solid conversion processes in a fixed bed furnace

NASA Astrophysics Data System (ADS)

Karim, Md. Rezwanul; Naser, Jamal

2017-06-01

Increasing demand for energy and rising concerns over global warming has urged the use of renewable energy sources to carry a sustainable development of the world. Bio mass is a renewable energy which has become an important fuel to produce thermal energy or electricity. It is an eco-friendly source of energy as it reduces carbon dioxide emissions. Combustion of solid biomass is a complex phenomenon due to its large varieties and physical structures. Among various systems, fixed bed combustion is the most commonly used technique for thermal conversion of solid biomass. But inadequate knowledge on complex solid conversion processes has limited the development of such combustion system. Numerical modelling of this combustion system has some advantages over experimental analysis. Many important system parameters (e.g. temperature, density, solid fraction) can be estimated inside the entire domain under different working conditions. In this work, a complete numerical model is used for solid conversion processes of biomass combustion in a fixed bed furnace. The combustion system is divided in to solid and gas phase. This model includes several sub models to characterize the solid phase of the combustion with several variables. User defined subroutines are used to introduce solid phase variables in commercial CFD code. Gas phase of combustion is resolved using built-in module of CFD code. Heat transfer model is modified to predict the temperature of solid and gas phases with special radiation heat transfer solution for considering the high absorptivity of the medium. Considering all solid conversion processes the solid phase variables are evaluated. Results obtained are discussed with reference from an experimental burner.

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.

Process for the conversion of carbonaceous feedstocks to particulate carbon and methanol

DOEpatents

Steinberg, Meyer; Grohse, Edward W.

1995-01-01

A process for the production of a pollutant-free particulate carbon (i.e., a substantially ash-, sulfur- and nitrogen-free carbon) from carbonaceous feedstocks. The basic process involves de-oxygenating one of the gas streams formed in a cyclic hydropyrolysis-methane pyrolysis process in order to improve conversion of the initial carbonaceous feedstock. De-oxygenation is effected by catalytically converting carbon monoxide, carbon dioxide, and hydrogen contained in one of the pyrolysis gas streams, preferably the latter, to a methanol co-product. There are thus produced two products whose use is known per se, viz., a substantially pollutant-free particulate carbon black and methanol. These products may be admixed in the form of a liquid slurry of carbon black in methanol.

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

Tan, Eric C.D.

This paper presents a comparative techno-economic analysis of four emerging conversion pathways from biomass to gasoline-, jet-, and diesel-range hydrocarbons via indirect liquefaction with specific focus on pathways utilizing oxygenated intermediates. The processing steps include: biomass-to-syngas via indirect gasification, gas cleanup, conversion of syngas to alcohols/oxygenates followed by conversion of alcohols/oxygenates to hydrocarbon blendstocks via dehydration, oligomerization, and hydrogenation.

Processes of conversion of a hot metal particle into aerogel through clusters

NASA Astrophysics Data System (ADS)

Smirnov, B. M.

2015-10-01

Processes are considered for conversion into a fractal structure of a hot metal micron-size particle that is located in a buffer gas or a gas flow and is heated by an external electric or electromagnetic source or by a plasma. The parameter of this heating is the particle temperature, which is the same in the entire particle volume because of its small size and high conductivity. Three processes determine the particle heat balance: particle radiation, evaporation of metal atoms from the particle surface, and heat transport to the surrounding gas due to its thermal conductivity. The particle heat balance is analyzed based on these processes, which are analogous to those for bulk metals with the small particle size, and its high temperature taken into account. Outside the particle, where the gas temperature is lower than on its surface, the formed metal vapor in a buffer gas flow is converted into clusters. Clusters grow as a result of coagulation until they become liquid, and then clusters form fractal aggregates if they are removed form the gas flow. Subsequently, associations of fractal aggregates join into a fractal structure. The rate of this process increases in medium electric fields, and the formed fractal structure has features of aerogels and fractal fibers. As a result of a chain of the above processes, a porous metal film may be manufactured for use as a filter or catalyst for gas flows.

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.

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

Tan, Eric C. D.; Talmadge, Michael; Dutta, Abhijit

This report was developed as part of the U.S. Department of Energy’s Bioenergy Technologies Office’s (BETO’s) efforts to enable the development of technologies for the production of infrastructure-compatible, cost-competitive liquid hydrocarbon fuels from lignocellulosic biomass feedstocks. The research funded by BETO is designed to advance the state of technology of biomass feedstock supply and logistics, conversion, and overall system sustainability. It is expected that these research improvements will be made within the 2022 timeframe. As part of their involvement in this research and development effort, the National Renewable Energy Laboratory and the Pacific Northwest National Laboratory investigate the economics ofmore » conversion pathways through the development of conceptual biorefinery process models and techno-economic analysis models. This report describes in detail one potential conversion process for the production of high-octane gasoline blendstock via indirect liquefaction of biomass. The processing steps of this pathway include the conversion of biomass to synthesis gas or syngas via indirect gasification, gas cleanup, catalytic conversion of syngas to methanol intermediate, methanol dehydration to dimethyl ether (DME), and catalytic conversion of DME to high-octane, gasoline-range hydrocarbon blendstock product. The conversion process configuration leverages technologies previously advanced by research funded by BETO and demonstrated in 2012 with the production of mixed alcohols from biomass. Biomass-derived syngas cleanup via reforming of tars and other hydrocarbons is one of the key technology advancements realized as part of this prior research and 2012 demonstrations. The process described in this report evaluates a new technology area for the downstream utilization of clean biomass-derived syngas for the production of high-octane hydrocarbon products through methanol and DME intermediates. In this process, methanol undergoes dehydration to DME, which is subsequently converted via homologation reactions to high-octane, gasoline-range hydrocarbon products.« less

Heavy Gas Conversion of the NASA Langley Transonic Dynamics Tunnel

NASA Technical Reports Server (NTRS)

Corliss, James M.; Cole, Stanley, R.

1998-01-01

The heavy gas test medium has recently been changed in the Transonic Dynamics Tunnel (TDT) at the NASA Langley Research Center. A NASA Construction of Facilities project has converted the TDT heavy gas from dichlorodifluoromethane (R12) to 1,1,1,2 tetrafluoroethane (R134a). The facility s heavy gas processing system was extensively modified to implement the conversion to R134a. Additional system modifications have improved operator interfaces, hardware reliability, and quality of the research data. The facility modifications included improvements to the heavy gas compressor and piping, the cryogenic heavy gas reclamation system, and the heavy gas control room. A series of wind tunnel characterization and calibration tests are underway. Results of the flow characterization tests show the TDT operating envelope in R134a to be very similar to the previous operating envelope in R12.

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

Analysis of biomass and waste gasification lean syngases combustion for power generation using spark ignition engines.

PubMed

Marculescu, Cosmin; Cenuşă, Victor; Alexe, Florin

2016-01-01

The paper presents a study for food processing industry waste to energy conversion using gasification and internal combustion engine for power generation. The biomass we used consisted in bones and meat residues sampled directly from the industrial line, characterised by high water content, about 42% in mass, and potential health risks. Using the feedstock properties, experimentally determined, two air-gasification process configurations were assessed and numerically modelled to quantify the effects on produced syngas properties. The study also focused on drying stage integration within the conversion chain: either external or integrated into the gasifier. To comply with environmental regulations on feedstock to syngas conversion both solutions were developed in a closed system using a modified down-draft gasifier that integrates the pyrolysis, gasification and partial oxidation stages. Good quality syngas with up to 19.1% - CO; 17% - H2; and 1.6% - CH4 can be produced. The syngas lower heating value may vary from 4.0 MJ/Nm(3) to 6.7 MJ/Nm(3) depending on process configuration. The influence of syngas fuel properties on spark ignition engines performances was studied in comparison to the natural gas (methane) and digestion biogas. In order to keep H2 molar quota below the detonation value of ⩽4% for the engines using syngas, characterised by higher hydrogen fraction, the air excess ratio in the combustion process must be increased to [2.2-2.8]. The results in this paper represent valuable data required by the design of waste to energy conversion chains with intermediate gas fuel production. The data is suitable for Otto engines characterised by power output below 1 MW, designed for natural gas consumption and fuelled with low calorific value gas fuels. Copyright © 2015 Elsevier Ltd. All rights reserved.

Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 3: Energy conversion subsystems and components. Part 3: Gasification, process fuels, and balance of plant

NASA Technical Reports Server (NTRS)

Boothe, W. A.; Corman, J. C.; Johnson, G. G.; Cassel, T. A. V.

1976-01-01

Results are presented of an investigation of gasification and clean fuels from coal. Factors discussed include: coal and coal transportation costs; clean liquid and gas fuel process efficiencies and costs; and cost, performance, and environmental intrusion elements of the integrated low-Btu coal gasification system. Cost estimates for the balance-of-plant requirements associated with advanced energy conversion systems utilizing coal or coal-derived fuels are included.

CO2 conversion in non-thermal plasma and plasma/g-C3N4 catalyst hybrid processes

NASA Astrophysics Data System (ADS)

Lu, Na; Sun, Danfeng; Zhang, Chuke; Jiang, Nan; Shang, Kefeng; Bao, Xiaoding; Li, Jie; Wu, Yan

2018-03-01

Carbon dioxide conversion at atmosphere pressure and low temperature has been studied in a cylindrical dielectric barrier discharge (DBD) reactor. Pure CO2 feed flows to the discharge zone and typical filamentary discharges were obtained in each half-cycle of the applied voltage. The gas temperature increased with discharge time and discharge power, which was found to affect the CO2 decomposition deeply. As the DBD reactor was cooled to ambient temperature, both the conversion of CO2 and the CO yield were enhanced. Especially the energy efficiencies changed slightly with the increase of discharge power and were much higher in cooling condition comparing to those without cooling. At a discharge power of 40 W, the energy efficiency under cooling condition was approximately six times more than that without cooling. Gas flow rate was observed to affect CO2 conversion and 0.1 L min-1 was obtained as optimum gas flow rate under cooling condition. In addition, the CO2 conversion rate in plasma/g-C3N4 catalyst hybrid system was twice times as that in plasma-alone system. In case of cooling, the existence of g-C3N4 catalyst contributed to a 47% increase of CO2 conversion compared to the sole plasma process. The maximum energy-efficiency with g-C3N4 was 0.26 mmol kJ-1 at 20 W, which increased by 157% compared to that without g-C3N4. The synergistic effect of DBD plasma with g-C3N4 on pure CO2 conversion was verified.

Renewable Natural Gas Clean-up Challenges and Applications

DTIC Science & Technology

2011-01-13

produced from digesters ─ Animal manure (dairy cows, swine) ─ Waste water treatment facilities > Methane from Landfills > RNG produced from...AGR used in process • Two stage + trim methanation reactor • Dehydration to achieve gas pipeline specifications ~ 70% conversion efficiency 21... digestion of agricultural waste for on-site electricity generation ─Altamont Landfill—Landfill gas (LFG) cleanup for production of liquefied natural gas

Alternative Fuels Data Center: Natural Gas Vehicle Conversions

Science.gov Websites

Conversions to someone by E-mail Share Alternative Fuels Data Center: Natural Gas Vehicle Conversions on Facebook Tweet about Alternative Fuels Data Center: Natural Gas Vehicle Conversions on Twitter Bookmark Alternative Fuels Data Center: Natural Gas Vehicle Conversions on Google Bookmark Alternative

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

Conversion of direct process high-boiling residue to monosilanes

DOEpatents

Brinson, Jonathan Ashley; Crum, Bruce Robert; Jarvis, Jr., Robert Frank

2000-01-01

A process for the production of monosilanes from the high-boiling residue resulting from the reaction of hydrogen chloride with silicon metalloid in a process typically referred to as the "direct process." The process comprises contacting a high-boiling residue resulting from the reaction of hydrogen chloride and silicon metalloid, with hydrogen gas in the presence of a catalytic amount of aluminum trichloride effective in promoting conversion of the high-boiling residue to monosilanes. The present process results in conversion of the high-boiling residue to monosilanes. At least a portion of the aluminum trichloride catalyst required for conduct of the process may be formed in situ during conduct of the direct process and isolation of the high-boiling residue.

Process for the conversion of carbonaceous feedstocks to particulate carbon and methanol

DOEpatents

Steinberg, M.; Grohse, E.W.

1995-06-27

A process is described for the production of a pollutant-free particulate carbon (i.e., a substantially ash-, sulfur- and nitrogen-free carbon) from carbonaceous feedstocks. The basic process involves de-oxygenating one of the gas streams formed in a cyclic hydropyrolysis-methane pyrolysis process in order to improve conversion of the initial carbonaceous feedstock. De-oxygenation is effected by catalytically converting carbon monoxide, carbon dioxide, and hydrogen contained in one of the pyrolysis gas streams, preferably the latter, to a methanol co-product. There are thus produced two products whose use is known per se, viz., a substantially pollutant-free particulate carbon black and methanol. These products may be admixed in the form of a liquid slurry of carbon black in methanol. 3 figs.

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.

Analysis of Efficiency of the Ship Propulsion System with Thermochemical Recuperation of Waste Heat

NASA Astrophysics Data System (ADS)

Cherednichenko, Oleksandr; Serbin, Serhiy

2018-03-01

One of the basic ways to reduce polluting emissions of ship power plants is application of innovative devices for on-board energy generation by means of secondary energy resources. The combined gas turbine and diesel engine plant with thermochemical recuperation of the heat of secondary energy resources has been considered. It is suggested to conduct the study with the help of mathematical modeling methods. The model takes into account basic physical correlations, material and thermal balances, phase equilibrium, and heat and mass transfer processes. The paper provides the results of mathematical modeling of the processes in a gas turbine and diesel engine power plant with thermochemical recuperation of the gas turbine exhaust gas heat by converting a hydrocarbon fuel. In such a plant, it is possible to reduce the specific fuel consumption of the diesel engine by 20%. The waste heat potential in a gas turbine can provide efficient hydrocarbon fuel conversion at the ratio of powers of the diesel and gas turbine engines being up to 6. When the diesel engine and gas turbine operate simultaneously with the use of the LNG vapor conversion products, the efficiency coefficient of the plant increases by 4-5%.

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.

Assessment of costs and benefits of flexible and alternative fuel use in the US transportation sector

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

None

1993-01-01

The primary objective of this report is to provide estimates of volumes and development costs of known nonassociated gas reserves in selected, potentially important supplier nations, using a standard set of costing algorithms and conventions. Estimates of undeveloped nonassociated gas reserves and the cost of drilling development wells, production equipment, gas processing facilities, and pipeline construction are made at the individual field level. A discounted cash-flow model of production, investment, and expenses is used to estimate the present value cost of developing each field on a per-thousand-cubic-foot (Mcf) basis. These gas resource cost estimates for individual accumulations (that is, fieldsmore » or groups of fields) then were aggregated into country-specific price-quantity curves. These curves represent the cost of developing and transporting natural gas to an export point suitable for tanker shipments or to a junction with a transmission line. The additional costs of LNG or methanol conversion are not included. A brief summary of the cost of conversion to methanol and transportation to the United States is contained in Appendix D: Implications of Gas Development Costs for Methanol Conversion.« less

Method for the photocatalytic conversion of gas hydrates

DOEpatents

Taylor, Charles E.; Noceti, Richard P.; Bockrath, Bradley C.

2001-01-01

A method for converting methane hydrates to methanol, as well as hydrogen, through exposure to light. The process includes conversion of methane hydrates by light where a radical initiator has been added, and may be modified to include the conversion of methane hydrates with light where a photocatalyst doped by a suitable metal and an electron transfer agent to produce methanol and hydrogen. The present invention operates at temperatures below 0.degree. C., and allows for the direct conversion of methane contained within the hydrate in situ.

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.

A Feasibility Study of Burning Waste Paper in Coal-Fired Boilers on Air Force Installations

DTIC Science & Technology

1993-09-01

from coal emissions is known as wet flue - gas desulfurization . This process involves the spraying of pulverized limestone (CaCO3 ) mixed with water...conversion to natural gas fuel or additional air : 13-tion controls . However, both of these options can be very costly, and a 6 less expensive alternative may...into the flue gas . The SO, is absorbed by the spray, creating calcium sulfite (Masters, 1991:349). The process is represented in equation form as CaCO3

Power generation based on biomass by combined fermentation and gasification--a new concept derived from experiments and modelling.

PubMed

Methling, Torsten; Armbrust, Nina; Haitz, Thilo; Speidel, Michael; Poboss, Norman; Braun-Unkhoff, Marina; Dieter, Heiko; Kempter-Regel, Brigitte; Kraaij, Gerard; Schliessmann, Ursula; Sterr, Yasemin; Wörner, Antje; Hirth, Thomas; Riedel, Uwe; Scheffknecht, Günter

2014-10-01

A new concept is proposed for combined fermentation (two-stage high-load fermenter) and gasification (two-stage fluidised bed gasifier with CO2 separation) of sewage sludge and wood, and the subsequent utilisation of the biogenic gases in a hybrid power plant, consisting of a solid oxide fuel cell and a gas turbine. The development and optimisation of the important processes of the new concept (fermentation, gasification, utilisation) are reported in detail. For the gas production, process parameters were experimentally and numerically investigated to achieve high conversion rates of biomass. For the product gas utilisation, important combustion properties (laminar flame speed, ignition delay time) were analysed numerically to evaluate machinery operation (reliability, emissions). Furthermore, the coupling of the processes was numerically analysed and optimised by means of integration of heat and mass flows. The high, simulated electrical efficiency of 42% including the conversion of raw biomass is promising for future power generation by biomass. Copyright © 2014 Elsevier Ltd. All rights reserved.

Conversion of H2 and CO2 to CH4 and acetate in fed-batch biogas reactors by mixed biogas community: a novel route for the power-to-gas concept.

PubMed

Szuhaj, Márk; Ács, Norbert; Tengölics, Roland; Bodor, Attila; Rákhely, Gábor; Kovács, Kornél L; Bagi, Zoltán

2016-01-01

Applications of the power-to-gas principle for the handling of surplus renewable electricity have been proposed. The feasibility of using hydrogenotrophic methanogens as CH4 generating catalysts has been demonstrated. Laboratory and scale-up experiments have corroborated the benefits of the CO2 mitigation via biotechnological conversion of H2 and CO2 to CH4. A major bottleneck in the process is the gas-liquid mass transfer of H2. Fed-batch reactor configuration was tested at mesophilic temperature in laboratory experiments in order to improve the contact time and H2 mass transfer between the gas and liquid phases. Effluent from an industrial biogas facility served as biocatalyst. The bicarbonate content of the effluent was depleted after some time, but the addition of stoichiometric CO2 sustained H2 conversion for an extended period of time and prevented a pH shift. The microbial community generated biogas from the added α-cellulose substrate with concomitant H2 conversion, but the organic substrate did not facilitate H2 consumption. Fed-batch operational mode allowed a fourfold increase in volumetric H2 load and a 6.5-fold augmentation of the CH4 formation rate relative to the CSTR reactor configuration. Acetate was the major by-product of the reaction. Fed-batch reactors significantly improve the efficiency of the biological power-to-gas process. Besides their storage function, biogas fermentation effluent reservoirs can serve as large-scale bio CH4 reactors. On the basis of this recognition, a novel concept is proposed, which merges biogas technology with other means of renewable electricity production for improved efficiency and sustainability.

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.

Postextraction Separation, On-Board Storage, and Catalytic Conversion of Methane in Natural Gas: A Review.

PubMed

Saha, Dipendu; Grappe, Hippolyte A; Chakraborty, Amlan; Orkoulas, Gerassimos

2016-10-12

In today's perspective, natural gas has gained considerable attention, due to its low emission, indigenous availability, and improvement in the extraction technology. Upon extraction, it undergoes several purification protocols including dehydration, sweetening, and inert rejection. Although purification is a commercially established technology, several drawbacks of the current process provide an essential impetus for developing newer separation protocols, most importantly, adsorption and membrane separation. This Review summarizes the needs of natural gas separation, gives an overview of the current technology, and provides a detailed discussion of the progress in research on separation and purification of natural gas including the benefits and drawbacks of each of the processes. The transportation sector is another growing sector of natural gas utilization, and it requires an efficient and safe on-board storage system. Compressed natural gas (CNG) and liquefied natural gas (LNG) are the most common forms in which natural gas can be stored. Adsorbed natural gas (ANG) is an alternate storage system of natural gas, which is advantageous as compared to CNG and LNG in terms of safety and also in terms of temperature and pressure requirements. This Review provides a detailed discussion on ANG along with computation predictions. The catalytic conversion of methane to different useful chemicals including syngas, methanol, formaldehyde, dimethyl ether, heavier hydrocarbons, aromatics, and hydrogen is also reviewed. Finally, direct utilization of methane onto fuel cells is also discussed.

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

McCarty, Jon; Berry, Brian; Lundberg, Kare

This final report describes a 2000-2003 program for the development of components and processes to enhance the commercialization of ultra-low emissions catalytic combustion in industrial gas turbines. The range of project tasks includes: development of more durable, lower-cost catalysts and catalytic combustor components; development and design of a catalytic pre-burner and a catalytic pilot burner for gas turbines, and on-site fuel conversion processing for utilization of liquid fuel.

Conversion of Carbon Dioxide into Ethanol by Electrochemical Synthesis Method Using Cu-Zn Electrode

NASA Astrophysics Data System (ADS)

Riyanto; Ramadan, S.; Fariduddin, S.; Aminudin, A. R.; Hayatri, A. K.

2018-01-01

Research on conversion of carbon dioxide into ethanol has been done. The conversion process is carried out in a sodium bicarbonate electrolyte solution in an electrochemical synthesis reactor. As cathode was used Cu-Zn, while as anode carbon was utilized. Variations of voltage, concentration of sodium bicarbonate electrolyte solution and time of electrolysis were performed to determine the optimum conditions to convert carbon dioxide into ethanol. Sample of the electrochemical synthesis process was analyzed by gas chromatography. From the result, it is found that the optimum conditions of the electrochemical synthesis process of carbon dioxide conversion into ethanol are voltage, concentration of sodium bicarbonate electrolyte solution and time of electrolysis are 3 volts, 0.4 M and 90 minutes with the ethanol concentration of 10.44%.

Electrochemical enhancement of nitric oxide removal from simulated lean-burn engine exhaust via solid oxide fuel cells.

PubMed

Huang, Ta-Jen; Wu, Chung-Ying; Lin, Yu-Hsien

2011-07-01

A solid oxide fuel cell (SOFC) unit is constructed with Ni-YSZ as the anode, YSZ as the electrolyte, and La(0.6)Sr(0.4)CoO(3)-Ce(0.9)Gd(0.1)O(1.95) as the cathode. The SOFC operation is performed at 600 °C with a cathode gas simulating the lean-burn engine exhaust and at various fixed voltage, at open-circuit voltage, and with an inert gas flowing over the anode side, respectively. Electrochemical enhancement of NO decomposition occurs when an operating voltage is generated; higher O(2) concentration leads to higher enhancement. Smaller NO concentration results in larger NO conversion. Higher operating voltage and higher O(2) concentration can lead to both higher NO conversion and lower fuel consumption. The molar rate of the consumption of the anode fuel can be very much smaller than that of NO to N(2) conversion. This makes the anode fuel consumed in the SOFC-DeNO(x) process to be much less than the equivalent amount of ammonia consumed in the urea-based selective catalytic reduction process. Additionally, the NO conversion increases with the addition of propylene and SO(2) into the cathode gas. These are beneficial for the application of the SOFC-DeNO(x) technology on treating diesel and other lean-burn engine exhausts.

The greenhouse gas emissions performance of cellulosic ethanol supply chains in Europe

PubMed Central

Slade, Raphael; Bauen, Ausilio; Shah, Nilay

2009-01-01

Background Calculating the greenhouse gas savings that may be attributed to biofuels is problematic because production systems are inherently complex and methods used to quantify savings are subjective. Differing approaches and interpretations have fuelled a debate about the environmental merit of biofuels, and consequently about the level of policy support that can be justified. This paper estimates and compares emissions from plausible supply chains for lignocellulosic ethanol production, exemplified using data specific to the UK and Sweden. The common elements that give rise to the greatest greenhouse gas emissions are identified and the sensitivity of total emissions to variations in these elements is estimated. The implications of including consequential impacts including indirect land-use change, and the effects of selecting alternative allocation methods on the interpretation of results are discussed. Results We find that the most important factors affecting supply chain emissions are the emissions embodied in biomass production, the use of electricity in the conversion process and potentially consequential impacts: indirect land-use change and fertiliser replacement. The large quantity of electricity consumed during enzyme manufacture suggests that enzymatic conversion processes may give rise to greater greenhouse gas emissions than the dilute acid conversion process, even though the dilute acid process has a somewhat lower ethanol yield. Conclusion The lignocellulosic ethanol supply chains considered here all lead to greenhouse gas savings relative to gasoline An important caveat to this is that if lignocellulosic ethanol production uses feedstocks that lead to indirect land-use change, or other significant consequential impacts, the benefit may be greatly reduced. Co-locating ethanol, electricity generation and enzyme production in a single facility may improve performance, particularly if this allows the number of energy intensive steps in enzyme production to be reduced, or if other process synergies are available. If biofuels policy in the EU remains contingent on favourable environmental performance then the multi-scale nature of bioenergy supply chains presents a genuine challenge. Lignocellulosic ethanol holds promise for emission reductions, but maximising greenhouse gas savings will not only require efficient supply chain design but also a better understanding of the spatial and temporal factors which affect overall performance. PMID:19682352

Energy conservation in coal conversion. Final report, September 15, 1977--September 1, 1978. Selected case studies and conservation methodologies

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

Purcupile, J.C.

The purpose of this study is to apply the methodologies developed in the Energy Conservation in Coal Conversion August, 1977 Progress Report - Contract No. EY77S024196 - to an energy efficient, near-term coal conversion process design, and to develop additional, general techniques for studying energy conservation and utilization in coal conversion processes. The process selected for study was the Ralph M. Parsons Company of Pasadena, California ''Oil/Gas Complex, Conceptual Design/Economic Analysis'' as described in R and D Report No. 114 - Interim Report No. 4, published March, 1977, ERDA Contract No. E(49-18)-1975. Thirteen papers representing possible alternative methods of energymore » conservation or waste heat utilization have been entered individually into EDB and ERA. (LTN)« less

Conversion of microalgae to jet fuel: process design and simulation.

PubMed

Wang, Hui-Yuan; Bluck, David; Van Wie, Bernard J

2014-09-01

Microalgae's aquatic, non-edible, highly genetically modifiable nature and fast growth rate are considered ideal for biomass conversion to liquid fuels providing promise for future shortages in fossil fuels and for reducing greenhouse gas and pollutant emissions from combustion. We demonstrate adaptability of PRO/II software by simulating a microalgae photo-bio-reactor and thermolysis with fixed conversion isothermal reactors adding a heat exchanger for thermolysis. We model a cooling tower and gas floatation with zero-duty flash drums adding solids removal for floatation. Properties data are from PRO/II's thermodynamic data manager. Hydrotreating is analyzed within PRO/II's case study option, made subject to Jet B fuel constraints, and we determine an optimal 6.8% bioleum bypass ratio, 230°C hydrotreater temperature, and 20:1 bottoms to overhead distillation ratio. Process economic feasibility occurs if cheap CO2, H2O and nutrient resources are available, along with solar energy and energy from byproduct combustion, and hydrotreater H2 from product reforming. Copyright © 2014 Elsevier Ltd. All rights reserved.

Production of hydrogen from biomass by catalytic steam reforming of fast pyrolysis oil

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

Czernik, S.; Wang, D.; Chornet, E.

1998-08-01

Hydrogen is the prototype of the environmentally cleanest fuel of interest for power generation using fuel cells and for transportation. The thermochemical conversion of biomass to hydrogen can be carried out through two distinct strategies: (a) gasification followed by water-gas shift conversion, and (b) catalytic steam reforming of specific fractions derived from fast pyrolysis and aqueous/steam processes of biomass. This paper presents the latter route that begins with fast pyrolysis of biomass to produce bio-oil. This oil (as a whole or its selected fractions) can be converted to hydrogen via catalytic steam reforming followed by a water-gas shift conversion step.more » Such a process has been demonstrated at the bench scale using model compounds, poplar oil aqueous fraction, and the whole pyrolysis oil with commercial Ni-based steam reforming catalysts. Hydrogen yields as high as 85% have been obtained. Catalyst initial activity can be recovered through regeneration cycles by steam or CO{sub 2} gasification of carbonaceous deposits.« less

Sulfur tolerant molten carbonate fuel cell anode and process

DOEpatents

Remick, Robert J.

1990-01-01

Molten carbonate fuel cell anodes incorporating a sulfur tolerant carbon monoxide to hydrogen water-gas-shift catalyst provide in situ conversion of carbon monoxide to hydrogen for improved fuel cell operation using fuel gas mixtures of over about 10 volume percent carbon monoxide and up to about 10 ppm hydrogen sulfide.

Conversion of Army Heating Plants to Coal: Three Case Studies

DTIC Science & Technology

1982-03-01

compared to the 50% wet sludge flue gas desulfurized product. All fly ash produced is collected without further processing. The product can be used to...Existing Turbine Generators 26 11 Picatinny Arsenal -- Summary of Capital Costs for Stoker Boilers, Flue Gas Desulfurization . New Turbine Generators...27 12 Picatinny Arsenal -- Summary of Operating Costs for Stoker Boilers, Flue Gas Desulfurization . New Turbine Generators 28 13 Picatinny Arsenal

A novel solid state fermentation coupled with gas stripping enhancing the sweet sorghum stalk conversion performance for bioethanol

PubMed Central

2014-01-01

Background Bioethanol production from biomass is becoming a hot topic internationally. Traditional static solid state fermentation (TS-SSF) for bioethanol production is similar to the traditional method of intermittent operation. The main problems of its large-scale intensive production are the low efficiency of mass and heat transfer and the high ethanol inhibition effect. In order to achieve continuous production and high conversion efficiency, gas stripping solid state fermentation (GS-SSF) for bioethanol production from sweet sorghum stalk (SSS) was systematically investigated in the present study. Results TS-SSF and GS-SSF were conducted and evaluated based on different SSS particle thicknesses under identical conditions. The ethanol yield reached 22.7 g/100 g dry SSS during GS-SSF, which was obviously higher than that during TS-SSF. The optimal initial gas stripping time, gas stripping temperature, fermentation time, and particle thickness of GS-SSF were 10 h, 35°C, 28 h, and 0.15 cm, respectively, and the corresponding ethanol stripping efficiency was 77.5%. The ethanol yield apparently increased by 30% with the particle thickness decreasing from 0.4 cm to 0.05 cm during GS-SSF. Meanwhile, the ethanol yield increased by 6% to 10% during GS-SSF compared with that during TS-SSF under the same particle thickness. The results revealed that gas stripping removed the ethanol inhibition effect and improved the mass and heat transfer efficiency, and hence strongly enhanced the solid state fermentation (SSF) performance of SSS. GS-SSF also eliminated the need for separate reactors and further simplified the bioethanol production process from SSS. As a result, a continuous conversion process of SSS and online separation of bioethanol were achieved by GS-SSF. Conclusions SSF coupled with gas stripping meet the requirements of high yield and efficient industrial bioethanol production. It should be a novel bioconversion process for bioethanol production from SSS biomass. PMID:24713041

Process Development for Hydrothermal Liquefaction of Algae Feedstocks in a Continuous-Flow Reactor

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

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

Wet algae slurries can be converted into an upgradeable biocrude by hydrothermal liquefaction (HTL). High levels of carbon conversion to gravity-separable biocrude product were accomplished at relatively low temperature (350 °C) in a continuous-flow, pressurized (sub-critical liquid water) environment (20 MPa). As opposed to earlier work in batch reactors reported by others, direct oil recovery was achieved without the use of a solvent and biomass trace components were removed by processing steps so that they did not cause process difficulties. High conversions were obtained even with high slurry concentrations of up to 35 wt% of dry solids. Catalytic hydrotreating wasmore » effectively applied for hydrodeoxygenation, hydrodenitrogenation, and hydrodesulfurization of the biocrude to form liquid hydrocarbon fuel. Catalytic hydrothermal gasification was effectively applied for HTL byproduct water cleanup and fuel gas production from water soluble organics, allowing the water to be considered for recycle of nutrients to the algae growth ponds. As a result, high conversion of algae to liquid hydrocarbon and gas products was found with low levels of organic contamination in the byproduct water. All three process steps were accomplished in bench-scale, continuous-flow reactor systems such that design data for process scale-up was generated.« less

Coal pump development phase 3

NASA Technical Reports Server (NTRS)

Kushida, R. O.; Sankur, V. D.; Gerbracht, F. G.; Mahajan, V.

1980-01-01

Techniques for achieving continuous coal sprays were studied. Coazial injection with gas and pressure atomization were studied. Coal particles, upon cooling, were found to be porous and fragile. Reactivity tests on the extruded coal showed overall conversion to gases and liquids unchanged from that of the raw coal. The potentials for applications of the coal pump to eight coal conversion processes were examined.

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

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

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.

Advanced Coal-Based Power Generations

NASA Technical Reports Server (NTRS)

Robson, F. L.

1982-01-01

Advanced power-generation systems using coal-derived fuels are evaluated in two-volume report. Report considers fuel cells, combined gas- and steam-turbine cycles, and magnetohydrodynamic (MHD) energy conversion. Presents technological status of each type of system and analyzes performance of each operating on medium-Btu fuel gas, either delivered via pipeline to powerplant or generated by coal-gasification process at plantsite.

Underground thermal generation of hydrocarbons from dry, southwestern coals

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

Vanderborgh, N.E.; Elliott, G.R.B.

1978-01-01

The LASL underground coal conversion concept produces intermediate-BTU fuel gas for nearby industries such as ''minemouth'' electric power plants, plus major byproducts in the form of liquid and gaseous hydrocarbons for feedstocks to chemical plants e.g., substitute natural gas (SNG) producers. The concept involves controlling the water influx and drying the coal, generating hydrocarbons, by pyrolysis and finally gasifying the residual char with O/sub 2//CO/sub 2/ or air/CO/sub 2/ mixtures to produce industrial fuel gases. Underground conversion can be frustrated by uncontrolled water in the coal bed. Moisture can (a) prevent combustion, (b) preclude fuel gas formation by lowering reactionmore » zone temperatures and creating kinetic problems, (c) ruin product gas quality by dropping temperatures into a thermodynamically unsatisfactory regime, (d) degrade an initially satisfactory fuel gas by consuming carbon monoxide, (e) waste large amounts of heat, and (f) isolate reaction zones so that the processing will bypass blocks of coal.« less

Feasibilities of a Coal-Biomass to Liquids Plant in Southern West Virginia

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

Bhattacharyya, Debangsu; DVallance, David; Henthorn, Greg

This project has generated comprehensive and realistic results of feasibilities for a coal-biomass to liquids (CBTL) plant in southern West Virginia; and evaluated the sensitivity of the analyses to various anticipated scenarios and parametric uncertainties. Specifically the project has addressed economic feasibility, technical feasibility, market feasibility, and financial feasibility. In the economic feasibility study, a multi-objective siting model was developed and was then used to identify and rank the suitable facility sites. Spatial models were also developed to assess the biomass and coal feedstock availabilities and economics. Environmental impact analysis was conducted mainly to assess life cycle analysis and greenhousemore » gas emission. Uncertainty and sensitivity analysis were also investigated in this study. Sensitivity analyses on required selling price (RSP) and greenhouse gas (GHG) emissions of CBTL fuels were conducted according to feedstock availability and price, biomass to coal mix ratio, conversion rate, internal rate of return (IRR), capital cost, operational and maintenance cost. The study of siting and capacity showed that feedstock mixed ratio limited the CBTL production. The price of coal had a more dominant effect on RSP than that of biomass. Different mix ratios in the feedstock and conversion rates led to RSP ranging from $104.3 - $157.9/bbl. LCA results indicated that GHG emissions ranged from 80.62 kg CO 2 eq to 101.46 kg CO2 eq/1,000 MJ of liquid fuel at various biomass to coal mix ratios and conversion rates if carbon capture and storage (CCS) was applied. Most of water and fossil energy were consumed in conversion process. Compared to petroleum-derived-liquid fuels, the reduction in GHG emissions could be between -2.7% and 16.2% with CBTL substitution. As for the technical study, three approaches of coal and biomass to liquids, direct, indirect and hybrid, were considered in the analysis. The process models including conceptual design, process modeling and process validation were developed and validated for different cases. Equipment design and capital costs were investigated on capital coast estimation and economical model validation. Material and energy balances and techno-economic analysis on base case were conducted for evaluation of projects. Also, sensitives studies of direct and indirect approaches were both used to evaluate the CBTL plant economic performance. In this study, techno-economic analysis were conducted in Aspen Process Economic Analyzer (APEA) environment for indirect, direct, and hybrid CBTL plants with CCS based on high fidelity process models developed in Aspen Plus and Excel. The process thermal efficiency ranges from 45% to 67%. The break-even oil price ranges from $86.1 to $100.6 per barrel for small scale (10000 bbl/day) CBTL plants and from $65.3 to $80.5 per barrel for large scale (50000 bbl/day) CBTL plants. Increasing biomass/coal ratio from 8/92 to 20/80 would increase the break-even oil price of indirect CBTL plant by $3/bbl and decrease the break-even oil price of direct CBTL plant by about $1/bbl. The order of carbon capture penalty is direct > indirect > hybrid. The order of capital investment is hybrid (with or without shale gas utilization) > direct (without shale gas utilization) > indirect > direct (with shale gas utilization). The order of thermal efficiency is direct > hybrid > indirect. The order of break-even oil price is hybrid (without shale gas utilization) > direct (without shale gas utilization) > hybrid (with shale gas utilization) > indirect > direct (with shale gas utilization).« less

Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 2: Advanced energy conversion systems. Part 1: Open-cycle gas turbines

NASA Technical Reports Server (NTRS)

Brown, D. H.; Corman, J. C.

1976-01-01

Ten energy conversion systems are defined and analyzed in terms of efficiency. These include: open-cycle gas turbine recuperative; open-cycle gas turbine; closed-cycle gas turbine; supercritical CO2 cycle; advanced steam cycle; liquid metal topping cycle; open-cycle MHD; closed-cycle inert gas MHD; closed-cycle liquid metal MHD; and fuel cells. Results are presented.

Converting oil shale to liquid fuels: energy inputs and greenhouse gas emissions of the Shell in situ conversion process.

PubMed

Brandt, Adam R

2008-10-01

Oil shale is a sedimentary rock that contains kerogen, a fossil organic material. Kerogen can be heated to produce oil and gas (retorted). This has traditionally been a CO2-intensive process. In this paper, the Shell in situ conversion process (ICP), which is a novel method of retorting oil shale in place, is analyzed. The ICP utilizes electricity to heat the underground shale over a period of 2 years. Hydrocarbons are produced using conventional oil production techniques, leaving shale oil coke within the formation. The energy inputs and outputs from the ICP, as applied to oil shales of the Green River formation, are modeled. Using these energy inputs, the greenhouse gas (GHG) emissions from the ICP are calculated and are compared to emissions from conventional petroleum. Energy outputs (as refined liquid fuel) are 1.2-1.6 times greater than the total primary energy inputs to the process. In the absence of capturing CO2 generated from electricity produced to fuel the process, well-to-pump GHG emissions are in the range of 30.6-37.1 grams of carbon equivalent per megajoule of liquid fuel produced. These full-fuel-cycle emissions are 21%-47% larger than those from conventionally produced petroleum-based fuels.

Ethanol internal steam reforming in intermediate temperature solid oxide fuel cell

NASA Astrophysics Data System (ADS)

Diethelm, Stefan; Van herle, Jan

This study investigates the performance of a standard Ni-YSZ anode supported cell under ethanol steam reforming operating conditions. Therefore, the fuel cell was directly operated with a steam/ethanol mixture (3 to 1 molar). Other gas mixtures were also used for comparison to check the conversion of ethanol and of reformate gases (H 2, CO) in the fuel cell. The electrochemical properties of the fuel cell fed with four different fuel compositions were characterized between 710 and 860 °C by I- V and EIS measurements at OCV and under polarization. In order to elucidate the limiting processes, impedance spectra obtained with different gas compositions were compared using the derivative of the real part of the impedance with respect of the natural logarithm of the frequency. Results show that internal steam reforming of ethanol takes place significantly on Ni-YSZ anode only above 760 °C. Comparisons of results obtained with reformate gas showed that the electrochemical cell performance is dominated by the conversion of hydrogen. The conversion of CO also occurs either directly or indirectly through the water-gas shift reaction but has a significant impact on the electrochemical performance only above 760 °C.

Biological removal of NOx from flue gas.

PubMed

Kumaraswamy, R; Muyzer, G; Kuenen, J G; Loosdrecht, M C M

2004-01-01

BioDeNOx is a novel integrated physico-chemical and biological process for the removal of nitrogen oxides (NOx) from flue gas. Due to the high temperature of flue gas the process is performed at a temperature between 50-55 degrees C. Flue gas containing CO2, O2, SO2 and NOx, is purged through Fe(II)EDTA2- containing liquid. The Fe(II)EDTA2- complex effectively binds the NOx; the bound NOx is converted into N2 in a complex reaction sequence. In this paper an overview of the potential microbial reactions in the BioDeNOx process is discussed. It is evident that though the process looks simple, due to the large number of parallel potential reactions and serial microbial conversions, it is much more complex. There is a need for a detailed investigation in order to properly understand and optimise the process.

Carbon capture by sorption-enhanced water-gas shift reaction process using hydrotalcite-based material

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

van Selow, E.R.; Cobden, P.D.; Verbraeken, P.A.

2009-05-15

A novel route for precombustion decarbonization is the sorption-enhanced water-gas shift (SEWGS) process. In this process carbon dioxide is removed from a synthesis gas at elevated temperature by adsorption. Simultaneously, carbon monoxide is converted to carbon dioxide by the water-gas shift reaction. The periodic adsorption and desorption of carbon dioxide is induced by a pressure swing cycle, and the cyclic capacity can be amplified by purging with steam. From previous studies is it known that for SEWGS applications, hydrotalcite-based materials are particularly attractive as sorbent, and commercial high-temperature shift catalysts can be used for the conversion of carbon monoxide. Tabletsmore » of a potassium promoted hydrotalcite-based material are characterized in both breakthrough and cyclic experiments in a 2 m tall fixed-bed reactor. When exposed to a mixture of carbon dioxide, steam, and nitrogen at 400{sup o}C, the material shows a breakthrough capacity of 1.4 mmol/g. In subsequent experiments the material was mixed with tablets of promoted iron-chromium shift catalyst and exposed to a mixture of carbon dioxide, carbon monoxide, steam, hydrogen, and nitrogen. It is demonstrated that carbon monoxide conversion can be enhanced to 100% in the presence of a carbon dioxide sorbent. At breakthrough, carbon monoxide and carbon dioxide simultaneously appear at the end of the bed. During more than 300 cycles of adsorption/reaction and desorption, the capture rate, and carbon monoxide conversion are confirmed to be stable. Two different cycle types are investigated: one cycle with a CO{sub 2} rinse step and one cycle with a steam rinse step. The performance of both SEWGS cycles are discussed.« less

Tri-reforming and combined reforming of methane for producing syngas with desired hydrogen/carbon monoxide ratios

NASA Astrophysics Data System (ADS)

Pan, Wei

This dissertation is an exploratory study of a new process concept for direct production of synthesis gas (CO + H2) with desired H 2/CO ratios (1.5--2.0) for methanol synthesis and F-T synthesis, using CO2 together with steam and unconverted O2 in flue gas from fossil fuel-fired electric power plants to react with methane or natural gas. This new process is called tri-reforming, referring to simultaneous CO2-steam-O2 reforming of methane or natural gas. This study included (1) The investigation of carbon formation in the tri-reforming process. For comparison, carbon formation in the combined reforming and CO2 reforming reaction was studied as well. (2) The effect of reaction conditions and feed compositions on equilibrium composition (e.g. H2/CO ratio) and equilibrium conversions in the tri-reforming process. (3) The role of catalysts in the tri-reforming process, especially the effect of catalysts on CO2 conversion in the presence of H 2O and O2. It was clearly evidenced from this study that CO in the product stream is probably the major source of carbon over Ni/Al2O3 in the equimolar CO2-CH4 reforming at 650°C and 1 atm. Addition of either O2 or H2O into the CO 2 reforming reaction system can suppress carbon formation. It was demonstrated that carbon-free operation can be achieved in the tri-reforming process. A thermodynamic comparison of tri-reforming with feed compositions of (H2O+CO2+0.5O2)/CH4 (mol ratio) = 1 showed that O2 improves equilibrium CH4 conversion, yet greatly decreases equilibrium CO2 conversion. H2O in tri-reforming has a significant effect on the H2/CO ratio in the products, while O2 has a minor effect. A kinetic study and catalytic performance tests indicated that the support in a supported catalyst has a significant role in enhancing CO2 conversion to CO in the presence of H2O and O2 in tri-reforming. The Ni/MgO catalyst showed superior performance with close to equilibrium CH4 and CO2 conversions at 850°C, 1 atm, and 32,000 ml/(h.gcat.). The apparent Activation energy for CH4 conversion over Ni/MgO was estimated to be 219 kJ/mol, which is higher than over Ni/Al2O 3 (69.1 kJ/mol) and Ni/MgO/CeZrO (67.4 kJ/mol). This may be attributed to less CH4 activation over Ni/MgO or to an experimental artifact caused by catalyst deactivation as reaction temperature decreases from 850°C to 750°C. With the decrease of temperature, Ni may be re-oxidized and form NiO-MgO solid solution in the presence of H2O, CO2, or O2. (Abstract shortened by UMI.)

Comparative TEA for Indirect Liquefaction Pathways to Distillate-Range Fuels via Oxygenated Intermediates

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

Tan, Eric; Snowden-Swan, Lesley J.; Talmadge, Michael

This paper presents a comparative techno-economic analysis of five conversion pathways from biomass to gasoline-, jet-, and diesel-range hydrocarbons via indirect liquefaction with specific focus on pathways utilizing oxygenated intermediates (derived either via thermochemical or biochemical conversion steps). The four emerging pathways of interest are compared with one conventional pathway (Fischer-Tropsch) for the production of the hydrocarbon blendstocks. The processing steps of the four emerging pathways include: biomass-to-syngas via indirect gasification, gas cleanup, conversion of syngas to alcohols/oxygenates, followed by conversion of alcohols/oxygenates to hydrocarbon blendstocks via dehydration, oligomerization, and hydrogenation. We show that the emerging pathways via oxygenated intermediatesmore » have the potential to be cost competitive with the conventional Fischer-Tropsch process. The evaluated pathways and the benchmark process generally exhibit similar fuel yields and carbon conversion efficiencies. The resulting minimum fuel selling prices are comparable to the benchmark at approximately $3.60 per gallon-gasoline equivalent, with potential for two new pathways to be more economically competitive. Additionally, the coproduct values can play an important role in the economics of the processes with oxygenated intermediates derived via syngas fermentation. Major cost drivers for the integrated processes are tied to achievable fuel yields and conversion efficiency of the intermediate steps, i.e., the production of oxygenates/alcohols from syngas and the conversion of oxygenates/alcohols to hydrocarbon fuels.« less

Advanced direct coal liquefaction concepts. Quarterly report, April 1, 1993--June 30, 1993

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

Berger, D.J.; Parker, R.J.; Simpson, P.L.

Construction and commissioning of the bench unit for operation of the first stage of the process was completed. Solubilization of Black Thunder coal using carbon monoxide and steam was successfully demonstrated in the counterflow reactor system. The results were comparable with those obtained in the autoclave with the exception that coal solubilization at the same nominal residence times was slightly lower. The bench unit has now been modified for two stage operation. The Wilsonville process derived solvent for Black Thunder coal (V-1074) was found to be essentially as stable as the previous solvent used in the autoclave runs (V-178 +more » 320) at reactor conditions. This solvent (V-1074) is, therefore, being used in the bench unit tests. Carbon monoxide may be replaced by synthesis gas for the coal solubilization step in the process. However, in autoclave tests, coal conversion was found to be dependent on the amount of carbon monoxide present in the synthesis gas. Coal conversions ranged from 88% for pure carbon monoxide to 67% for a 25:75 carbon monoxide/hydrogen mixture at equivalent conditions. Two stage liquefaction tests were completed in the autoclave using a disposable catalyst (FeS) and hydrogen in the second stage. Increased coal conversion, higher gas and oil and lower asphaltene and preasphaltene yields were observed as expected. However, no hydrogen consumption was observed in the second stage. Other conditions, in particular, alternate catalyst systems will be explored.« less

Energy Conversion Loop: A Testbed for Nuclear Hybrid Energy Systems Use in Biomass Pyrolysis

NASA Astrophysics Data System (ADS)

Verner, Kelley M.

Nuclear hybrid energy systems are a possible solution for contemporary energy challenges. Nuclear energy produces electricity without greenhouse gas emissions. However, nuclear power production is not as flexible as electrical grids demand and renewables create highly variable electricity. Nuclear hybrid energy systems are able to address both of these problems. Wasted heat can be used in processes such as desalination, hydrogen production, or biofuel production. This research explores the possible uses of nuclear process heat in bio-oil production via biomass pyrolysis. The energy conversion loop is a testbed designed and built to mimic the heat from a nuclear reactor. Small scale biomass pyrolysis experiments were performed and compared to results from the energy conversion loop tests to determine future pyrolysis experimentation with the energy conversion loop. Further improvements must be made to the energy conversion loop before more complex experiments may be performed. The current conditions produced by the energy conversion loop are not conducive for current biomass pyrolysis experimentation.tion.

Process Evaluation - Steam Reforming of Diesel Fuel Oil

DTIC Science & Technology

1980-02-15

Table 9. HIDROGEN CONVERSION RELATIVE TO TEMPERATURE, SPACE, VELOCITY, AND H20/C RATIO Oil Feed, Gas Product ,Run No. Temperature, *F H2,O/C Ratio igram...steam reforming diesel fuel, but with the production of naphthalene after 30 hours. Hydrogen production remained stable through the 86 hours of the test...79-C-0048. Hydrogen-rich gas was produced over a wide range of reaction conditions. This product gas contained small amounts of ethylene and !nzene

Co-generated fast pyrolysis biochar mitigates green-house gas emissions and increases carbon sequestration in temperate soils

USDA-ARS?s Scientific Manuscript database

Biochar (BC) is a product of thermochemical conversion of biomass via pyrolysis, together with gas (syngas), liquid (bio-oil), and heat. Fast pyrolysis is a promising process for bio-oil generation, which leaves 10-30% of the original biomass as char. When applied to soils, BC may increase soil C s...

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

Tan, Eric C. D.; Talmadge, Michael; Dutta, Abhijit

This paper describes in detail one potential conversion process for the production of high-octane gasoline blendstock via indirect liquefaction of biomass. The processing steps of this pathway include the conversion of biomass to synthesis gas via indirect gasification, gas clean-up via reforming of tars and other hydrocarbons, catalytic conversion of syngas to methanol, methanol dehydration to dimethyl ether (DME), and the homologation of DME over a zeolite catalyst to high-octane gasoline-range hydrocarbon products. The current process configuration has similarities to conventional methanol-to-gasoline (MTG) technologies, but there are key distinctions, specifically regarding the product slate, catalysts, and reactor conditions. A techno-economicmore » analysis is performed to investigate the production of high-octane gasoline blendstock. The design features a processing daily capacity of 2000 tonnes (2205 short tons) of dry biomass. The process yields 271 liters of liquid fuel per dry tonne of biomass (65 gal/dry ton), for an annual fuel production rate of 178 million liters (47 MM gal) at 90% on-stream time. The estimated total capital investment for an nth-plant is $438 million. The resulting minimum fuel selling price (MFSP) is $0.86 per liter or $3.25 per gallon in 2011 US dollars. A rigorous sensitivity analysis captures uncertainties in costs and plant performance. Sustainability metrics for the conversion process are quantified and assessed. The potential premium value of the high-octane gasoline blendstock is examined and found to be at least as competitive as fossil-derived blendstocks. A simple blending strategy is proposed to demonstrate the potential for blending the biomass-derived blendstock with petroleum-derived intermediates. Published 2015. This article is a U.S. Government work and is in the public domain in the USA. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.« less

Comparative evaluation of solar, fission, fusion, and fossil energy resources. Part 4: Energy from fossil fuels

NASA Technical Reports Server (NTRS)

Williams, J. R.

1974-01-01

The conversion of fossil-fired power plants now burning oil or gas to burn coal is discussed along with the relaxation of air quality standards and the development of coal gasification processes to insure a continued supply of gas from coal. The location of oil fields, refining areas, natural gas fields, and pipelines in the U.S. is shown. The technologies of modern fossil-fired boilers and gas turbines are defined along with the new technologies of fluid-bed boilers and MHD generators.

Ceramic membranes with mixed conductivity and their application

NASA Astrophysics Data System (ADS)

Kozhevnikov, V. L.; Leonidov, I. A.; Patrakeev, M. V.

2013-08-01

Data on the catalytic reactors with ceramic membranes possessing mixed oxygen ion and electronic conductivity that make it possible to integrate the processes of oxygen separation and oxidation are analyzed and generalized. The development of this approach is of interest for the design of energy efficient and environmentally friendly processes for processing natural gas and other raw materials. The general issues concerning the primary processing of light alkanes in reactors with oxygen separating membranes are expounded and general demands to the membrane materials are discussed. Particular attention is paid to the process of oxidative conversion of methane to synthesis gas. The bibliography includes 110 references.

Periodic density modulation for quasi-phase-matching of optical frequency conversion is inefficient under shallow focusing and constant ambient pressure.

PubMed

Hadas, Itai; Bahabad, Alon

2016-09-01

The two main mechanisms of a periodic density modulation relevant to nonlinear optical conversion in a gas medium are spatial modulations of the index of refraction and of the number of emitters. For a one-dimensional model neglecting focusing and using a constant ambient pressure, it is shown theoretically and demonstrated numerically that the effects of these two mechanisms during frequency conversion cancel each other exactly. Under the considered conditions, this makes density modulation inefficient for quasi-phase-matching an optical frequency conversion process. This result is particularly relevant for high-order harmonic generation.

A comparison of producer gas, biochar, and activated carbon from two distributed scale thermochemical conversion systems used to process forest biomass

Treesearch

Nathaniel Anderson; J. Greg Jones; Deborah Page-Dumroese; Daniel McCollum; Stephen Baker; Daniel Loeffler; Woodam Chung

2013-01-01

Thermochemical biomass conversion systems have the potential to produce heat, power, fuels and other products from forest biomass at distributed scales that meet the needs of some forest industry facilities. However, many of these systems have not been deployed in this sector and the products they produce from forest biomass have not been adequately described or...

Conversion of laser energy to gas kinetic energy

NASA Technical Reports Server (NTRS)

Caledonia, G. E.

1976-01-01

Techniques for the gas phase absorption of laser radiation for ultimate conversion to gas kinetic energy are discussed. Particular emphasis is placed on absorption by the vibration rotation bands of diatomic molecules at high pressures. This high pressure absorption appears to offer efficient conversion of laser energy to gas translational energy. Bleaching and chemical effects are minimized and the variation of the total absorption coefficient with temperature is minimal.

Electricity generation from synthesis gas by microbial processes: CO fermentation and microbial fuel cell technology.

PubMed

Kim, Daehee; Chang, In Seop

2009-10-01

A microbiological process was established to harvest electricity from the carbon monoxide (CO). A CO fermenter was enriched with CO as the sole carbon source. The DGGE/DNA sequencing results showed that Acetobacterium spp. were enriched from the anaerobic digester fluid. After the fermenter was operated under continuous mode, the products were then continuously fed to the microbial fuel cell (MFC) to generate electricity. Even though the conversion yield was quite low, this study proved that synthesis gas (syn-gas) can be converted to electricity with the aid of microbes that do not possess the drawbacks of metal catalysts of conventional methods.

Determination of epichlorohydrin and 1,3-dichloro-2-propanol in synthesis of cationic etherifying reagent by headspace gas chromatography.

PubMed

Tao, Zheng-Yi; Chai, Xin-Sheng; Wu, Shu-Bin

2011-09-16

This study demonstrates a headspace gas chromatographic(HS-GC) technique for the determination of residual epichlorohydrin (ECH) and generated 1,3-dichloro-2-propanol (DCP) in synthesis process of 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHTAC). By a weight-based sampling method, coupled with significant dilution in 15.8% sodium sulfate and 0.1% silver nitrate mixed solution rapidly, the sample for HS-GC analysis is prepared. Based on the reaction stoichiometry, the conversion (R) of CHTAC during the synthesis process can be calculated from sampling weight and GC peak area. The results showed that the method has a good measurement precision (RSD<2.5%) and accuracy (recovery=101-104%) for the quantification of both ECH and DCP in the process samples. The present method is simple and accurate, which can be used for the efficient determination of the CHTAC conversion in the synthesis research. Copyright © 2011 Elsevier B.V. All rights reserved.

Updraft gasification of poultry litter at farm-scale--A case study.

PubMed

Taupe, N C; Lynch, D; Wnetrzak, R; Kwapinska, M; Kwapinski, W; Leahy, J J

2016-04-01

Farm and animal wastes are increasingly being investigated for thermochemical conversion, such as gasification, due to the urgent necessity of finding new waste treatment options. We report on an investigation of the use of a farm-scale, auto-thermal gasification system for the production of a heating gas using poultry litter (PL) as a feedstock. The gasification process was robust and reliable. The PL's ash melting temperature was 639°C, therefore the reactor temperature was kept around this value. As a result of the low reactor temperature the process performance parameters were low, with a cold gas efficiency (CGE) of 0.26 and a carbon conversion efficiency (CCE) of 0.44. The calorific value of the clean product gas was 3.39 MJ m(-3)N (LHV). The tar was collected as an emulsion containing 87 wt.% water and the extracted organic compounds were identified. The residual char exceeds thresholds for Zn and Cu to obtain European biochar certification; however, has potential to be classified as a pyrogenic carbonaceous material (PCM), which resembles a high nutrient biochar. Copyright © 2016 Elsevier Ltd. All rights reserved.

Analysis of the gas phase reactivity of chlorosilanes.

PubMed

Ravasio, Stefano; Masi, Maurizio; Cavallotti, Carlo

2013-06-27

Trichlorosilane is the most used precursor to deposit silicon for photovoltaic applications. Despite of this, its gas phase and surface kinetics have not yet been completely understood. In the present work, it is reported a systematic investigation aimed at determining what is the dominant gas phase chemistry active during the chemical vapor deposition of Si from trichlorosilane. The gas phase mechanism was developed calculating the rate constant of each reaction using conventional transition state theory in the rigid rotor-harmonic oscillator approximation. Torsional vibrations were described using a hindered rotor model. Structures and vibrational frequencies of reactants and transition states were determined at the B3LYP/6-31+G(d,p) level, while potential energy surfaces and activation energies were computed at the CCSD(T) level using aug-cc-pVDZ and aug-cc-pVTZ basis sets extrapolating to the complete basis set limit. As gas phase and surface reactivities are mutually interlinked, simulations were performed using a microkinetic surface mechanism. It was found that the gas phase reactivity follows two different routes. The disilane mechanism, in which the formation of disilanes as reaction intermediates favors the conversion between the most stable monosilane species, and the radical pathway, initiated by the decomposition of Si2HCl5 and followed by a series of fast propagation reactions. Though both mechanisms are active during deposition, the simulations revealed that above a certain temperature and conversion threshold the radical mechanism provides a faster route for the conversion of SiHCl3 into SiCl4, a reaction that favors the overall Si deposition process as it is associated with the consumption of HCl, a fast etchant of Si. Also, this study shows that the formation of disilanes as reactant intermediates promotes significantly the gas phase reactivity, as they contribute both to the initiation of radical chain mechanisms and provide a catalytic route for the conversion between the most stable monosilanes.

Carbon dioxide capture from a cement manufacturing process

DOEpatents

Blount, Gerald C [North Augusta, SC; Falta, Ronald W [Seneca, SC; Siddall, Alvin A [Aiken, SC

2011-07-12

A process of manufacturing cement clinker is provided in which a clean supply of CO.sub.2 gas may be captured. The process also involves using an open loop conversion of CaO/MgO from a calciner to capture CO.sub.2 from combustion flue gases thereby forming CaCO.sub.3/CaMg(CO.sub.3).sub.2. The CaCO.sub.3/CaMg(CO.sub.3).sub.2 is then returned to the calciner where CO.sub.2 gas is evolved. The evolved CO.sub.2 gas, along with other evolved CO.sub.2 gases from the calciner are removed from the calciner. The reactants (CaO/MgO) are feed to a high temperature calciner for control of the clinker production composition.

Tunable, self-powered integrated arc plasma-melter vitrification system for waste treatment and resource recovery

DOEpatents

Titus, Charles H.; Cohn, Daniel R.; Surma, Jeffrey E.

1998-01-01

The present invention provides a relatively compact self-powered, tunable waste conversion system and apparatus which has the advantage of highly robust operation which provides complete or substantially complete conversion of a wide range of waste streams into useful gas and a stable, nonleachable solid product at a single location with greatly reduced air pollution to meet air quality standards. The system provides the capability for highly efficient conversion of waste into high quality combustible gas and for high efficiency conversion of the gas into electricity by utilizing a high efficiency gas turbine or by an internal combustion engine. The solid product can be suitable for various commercial applications. Alternatively, the solid product stream, which is a safe, stable material, may be disposed of without special considerations as hazardous material. In the preferred embodiment of the invention, the arc plasma furnace and joule heated melter are formed as a fully integrated unit with a common melt pool having circuit arrangements for the simultaneous independently controllable operation of both the arc plasma and the joule heated portions of the unit without interference with one another. The preferred configuration of this embodiment of the invention utilizes two arc plasma electrodes with an elongated chamber for the molten pool such that the molten pool is capable of providing conducting paths between electrodes. The apparatus may additionally be employed with reduced or without further use of the gases generated by the conversion process. The apparatus may be employed as a self-powered or net electricity producing unit where use of an auxiliary fuel provides the required level of electricity production.

Compressed Natural Gas and Liquefied Petroleum Gas Conversions: The National Renewable Energy Laboratory's Experience

DOT National Transportation Integrated Search

1996-04-01

The National Renewable Energy Laboratory (NREL) contracted with conversion : companies in six states to convert approximately 900 light-duty Federal fleet : vehicles to operate on compressed natural gas (CNG) or liquefied petroleum gas : (LPG). After...

CO2 Injection Into CH4 Hydrate Reservoirs: Quantifying Controls of Micro-Scale Processes

NASA Astrophysics Data System (ADS)

Bigalke, N. K.; Deusner, C.; Kossel, E.; Haeckel, M.

2014-12-01

The exchangeability of methane for carbon dioxide in gas hydrates opens the possibility of producing emission-neutral hydrocarbon energy. Recent field tests have shown that the production of natural gas from gas hydrates is feasible via injection of carbon dioxide into sandy, methane-hydrate-bearing sediment strata. Industrial-scale application of this method requires identification of thermo- and fluid-dynamic as well as kinetic controls on methane yield from and carbon dioxide retention within the reservoir. Extraction of gas via injection of carbon dioxide into the hydrate reservoir triggers a number of macroscopic effects, which are revealed for example by changes of the hydraulic conductivity and geomechanical stability. Thus far, due to analytical limitations, localized reactions and fluid-flow phenomena held responsible for these effects remain unresolved on the microscale (1 µm - 1 mm) and at near-natural reservoir conditions. We address this deficit by showing results from high-resolution, two-dimensional Raman spectroscopy mappings of an artificial hydrate reservoir during carbon dioxide injection under realistic reservoir conditions. The experiments allow us to resolve hydrate conversion rate and efficiency as well as activation of fluid pathways in space and time and their effect on methane yield, carbon-dioxide retention and hydraulic conductivity of the reservoir. We hypothesize that the conversion of single hydrate grains is a diffusion-controlled process which starts at the grain surface before continuing into the grain interior and show that the conversion can be modeled simply by using published permeation coefficients for CO2 and CH4 in hydrate and grain size as only input parameters.

Production of Renewable Natural Gas from Waste Biomass

NASA Astrophysics Data System (ADS)

Kumar, Sachin; Suresh, S.; Arisutha, S.

2013-03-01

Biomass energy is expected to make a major contribution to the replacement of fossil fuels. Methane produced from biomass is referred to as bio-methane, green gas, bio-substitute natural gas or renewable natural gas (RNG) when it is used as a transport fuel. Research on upgrading of the cleaned producer gas to RNG is still ongoing. The present study deals with the conversion of woody biomass into fuels, RNG using gasifier. The various effects of parameters like temperature, pressure, and tar formation on conversion were also studied. The complete carbon conversion was observed at 480 °C and tar yield was significantly less. When biomass was gasified with and without catalyst at about 28 s residence time, ~75 % (w/w) and 88 % (w/w) carbon conversion for without and with catalyst was observed. The interest in RNG is growing; several initiatives to demonstrate the thermal-chemical conversion of biomass into methane and/or RNG are under development.

Linam Ranch cryogenic gas plant: A design and operating retrospective

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

Harwell, L.J.; Kuscinski, J.

1999-07-01

GPM Gas Corporation's Linam Ranch Gas Plant is the processing hub of their southeastern New Mexico gathering system, producing a y-grade NGL product which is pipelined primarily to the Phillips petrochemical complex at Sweeney, Texas, GPM acquired the facility near Hobbs, N.M. late in 1994 when it was still operating as a refrigerated lean oil plant, renamed it, and commenced an upgrade project culminating in its conversion to a high recovery cryogenic facility in early 1996 with a processing capacity of 150 MMscfd. Facilities that were upgraded included inlet liquids receiving and handling, the amine system, mol sieve dehydration, themore » sulfur recovery unit, inlet compression, and the propane refrigeration system. A Foxboro I/A DCS was also placed into operation. The lean oil system was replaced with a high recovery turboexpander unit supplied by KTI Fish based on their Flash Vapor Reflux (FVR) process. Resulting ethane recovery was greater than 95% for the new facilities. New residue compression units were installed including steam generators on the turbine exhausts, which complemented the existing plant steam system. During the three years since conversion to cryogenic operation, GPM has steadily improved plant operations. Expansion of the mol sieve dehydration system and retrofit of evaporation combustion air cooling on gas turbines have expanded nameplate capacity to 170 MMscfd while maintaining ethane recovery at 95%. Future expansion to 200 MMscfd with high recovery is achievable. In addition, creative use of the Foxboro DCS has been employed to implement advanced control schemes for handling inlet liquid slugs, gas and amine balancing for parallel amine contactors, improved sulfur recovery unit (SRU) trim air control, and constraint-based process optimization to maximize horsepower utilization and ethane recovery. Some challenges remain, leaving room for additional improvements. However, GPM's progress so far has resulted in a current ethane recovery level in excess of 97% when processing gas at the original design throughput of 150 MMscfd.« less

Bioconversion of waste biomass to useful products

DOEpatents

Grady, J.L.; Chen, G.J.

1998-10-13

A process is provided for converting waste biomass to useful products by gasifying the biomass to produce synthesis gas and converting the synthesis gas substrate to one or more useful products. The present invention is directed to the conversion of biomass wastes including municipal solid waste, sewage sludge, plastic, tires, agricultural residues and the like, as well as coal, to useful products such as hydrogen, ethanol and acetic acid. The overall process includes the steps of gasifying the waste biomass to produce raw synthesis gas, cooling the synthesis gas, converting the synthesis gas to the desired product or products using anaerobic bioconversion, and then recovering the product or products. In accordance with a particular embodiment of the present invention, waste biomass is converted to synthesis gas containing carbon monoxide and, then, the carbon monoxide is converted to hydrogen by an anaerobic microorganism ERIH2, Bacillus smithii ATCC No. 55404. 82 figs.

Bioconversion of waste biomass to useful products

DOEpatents

Grady, James L.; Chen, Guang Jiong

1998-01-01

A process is provided for converting waste biomass to useful products by gasifying the biomass to produce synthesis gas and converting the synthesis gas substrate to one or more useful products. The present invention is directed to the conversion of biomass wastes including municipal solid waste, sewage sludge, plastic, tires, agricultural residues and the like, as well as coal, to useful products such as hydrogen, ethanol and acetic acid. The overall process includes the steps of gasifying the waste biomass to produce raw synthesis gas, cooling the synthesis gas, converting the synthesis gas to the desired product or products using anaerobic bioconversion, and then recovering the product or products. In accordance with a particular embodiment of the present invention, waste biomass is converted to synthesis gas containing carbon monoxide and, then, the carbon monoxide is converted to hydrogen by an anaerobic microorganism ERIH2, bacillus smithii ATCC No. 55404.

The economic production of alcohol fuels from coal-derived synthesis gas

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

Kugler, E.L.; Dadyburjor, D.B.; Yang, R.Y.K.

1995-12-31

The objectives of this project are to discover, (1) study and evaluate novel heterogeneous catalytic systems for the production of oxygenated fuel enhancers from synthesis gas. Specifically, alternative methods of preparing catalysts are to be investigated, and novel catalysts, including sulfur-tolerant ones, are to be pursued. (Task 1); (2) explore, analytically and on the bench scale, novel reactor and process concepts for use in converting syngas to liquid fuel products. (Task 1); (3) simulate by computer the most energy efficient and economically efficient process for converting coal to energy, with primary focus on converting syngas to fuel alcohols. (Task 2);more » (4) develop on the bench scale the best holistic combination of chemistry, catalyst, reactor and total process configuration integrated with the overall coal conversion process to achieve economic optimization for the conversion of syngas to liquid products within the framework of achieving the maximum cost effective transformation of coal to energy equivalents. (Tasks 1 and 2); and (5) evaluate the combustion, emission and performance characteristics of fuel alcohols and blends of alcohols with petroleum-based fuels. (Task 2)« less

Fuel Gas Demonstration Plant Program. Volume I. Demonstration plant

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

Not Available

1979-01-01

The objective of this project is for Babcock Contractors Inc. (BCI) to provide process designs, and gasifier retort design for a fuel gas demonstration plant for Erie Mining Company at Hoyt Lake, Minnesota. The fuel gas produced will be used to supplement natural gas and fuel oil for iron ore pellet induration. The fuel gas demonstration plant will consist of five stirred, two-stage fixed-bed gasifier retorts capable of handling caking and non-caking coals, and provisions for the installation of a sixth retort. The process and unit design has been based on operation with caking coals; however, the retorts have beenmore » designed for easy conversion to handle non-caking coals. The demonstration unit has been designed to provide for expansion to a commercial plant (described in Commercial Plant Package) in an economical manner.« less

Catalyst and process development for synthesis gas conversion to isobutylene. Quarterly report, October 1, 1992--December 31, 1992

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

Anthony, R.G.; Akgerman, A.

1993-02-01

The objectives of this project are to develop a new catalyst, the kinetics for this catalyst, reactor models for trickle bed, slurry and fixed bed reactors, and simulate the performance of fixed bed trickle flow reactors, slurry flow reactors, and fixed bed gas phase reactors for conversion of a hydrogen lean synthesis gas to isobutylene. The goals for the quarter include: (1) Conduct experiments using a trickle bed reactor to determine the effect of reactor type on the product distribution. (2) Use spherical pellets of silica as a support for zirconia for the purpose of increasing surface, area and performancemore » of the catalysts. (3) Conduct exploratory experiments to determine the effect of super critical drying of the catalyst on the catalyst surface area and performance. (4) Prepare a ceria/zirconia catalyst by the precipitation method.« less

I(CO)/N(H2) conversions and molecular gas abundances in spiral and irregular galaxies

NASA Technical Reports Server (NTRS)

Maloney, Philip; Black, John H.

1988-01-01

Observations of emission in the J = 1-0 rotational transition of interstellar CO are used to obtain column densities and masses of hydrogen. By taking into account the effects of variations in molecular cloud parameters on conversion factors between integrated CO intensity and molecular hydrogen column density, it is shown that conversion factors are very sensitive to the kinetic temperature of the emitting gas. Results indicate that the gas temperatures in systems with high star formation rates can be quite high, and it is suggested that use of a standard conversion factor will lead to systematic overestimation of the amount of molecular gas.

Exploration of government policy structure which support and block energy transition process in indonesia using system dynamics model

NASA Astrophysics Data System (ADS)

Destyanto, A. R.; Silalahi, T. D.; Hidayatno, A.

2017-11-01

System dynamic modeling is widely used to predict and simulate the energy system in several countries. One of the applications of system dynamics is to evaluate national energy policy alternatives, and energy efficiency analysis. Using system dynamic modeling, this research aims to evaluate the energy transition policy that has been implemented in Indonesia on the past conversion program of kerosene to LPG for household cook fuel consumption, which considered as successful energy transition program implemented since 2007. This research is important since Indonesia considered not yet succeeded to execute another energy transition program on conversion program of oil fuel to gas fuel for transportation that has started since 1989. The aim of this research is to explore which policy intervention that has significant contribution to support or even block the conversion program. Findings in this simulation show that policy intervention to withdraw the kerosene supply and government push to increase production capacity of the support equipment industries (gas stove, regulator, and LPG Cylinder) is the main influence on the success of the program conversion program.

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.

Cogeneration Technology Alternatives Study (CTAS) Volume 5: Analytical approach and results

NASA Technical Reports Server (NTRS)

1980-01-01

Data and information in the area of advanced energy conversion systems for industrial cogeneration applications in the 1985 to 2000 time period are provided. Six current and thirty-six advanced energy conversion systems were defined and combined with appropriate balance of plant equipment. Twenty-six industrial processes were selected from among the high energy consuming industries to serve as a framework for the study. Each conversion system was analyzed as a cogenerator with each industrial plant. Fuel consumption, costs, and environmental intrusion were evaluated and compared to corresponding traditional values. Various cogeneration strategies were analyzed and both topping and bottoming (using industrial by-product heat) applications were included. The advanced energy conversion technologies indicated reduced fuel consumption, costs, and emissions. Typically fuel energy savings of 10 to 25 percent were predicted compared to traditional on site furnaces and utility electricity. Gas turbines and combined cycles indicated high overall annual cost savings. Steam turbines and gas turbines produced high estimated returns. In some applications, diesels were most efficient. The advanced technologies used coal derived fuels, or coal with advanced fluid bed combustion or on site gasification systems.

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.

Physicochemical Processes on Ice Dust Towards Deuterium Enrichment

NASA Astrophysics Data System (ADS)

Watanabe, Naoki

2017-06-01

Water and some organic molecules were found to be deuterium enriched toward various astronomical targets. Understanding the deuterium-fractionation process pertains directly to know how and when molecules are created. Although gas phase chemistry is certainly important for deuterium enrichment, the role of physicochemical processes on the dust surfaces should be also considered. In fact, the extreme deuterium enrichment of formaldehyde and methanol requires the dust grain-surface process. In this context, we have performed a series of experiments on the formation of deuterated species of water and simple organic molecules. From the results of these experiments and related works, I will discuss the key processes for the deuterium enrichment on dust. For deuterium chemistry, another important issue is the ortho-to-para ratio (OPR) of H_{2}, which is closely related to the formation of H_{2}D^{+} and thus the deuterium fractionation of molecules in the gas phase. Because the radiative nuclear spin conversion of H_{2} is forbidden, the ortho-para conversion is very slow in the gas phase. In contrast, it was not obvious how the nuclear spins behave on cosmic dust. Therefore, it is desirable to understand how the OPR of H_{2} is determined on the dust surfaces. We have tackled this issue experimentally. Using experimental techniques of molecular beam, photostimulated-desorption, and resonance-enhanced multiphoton ionization, we measured the OPRs of H_{2} photodesorbed from amorphous solid water at around 10 K, which is an ice dust analogue. It was first demonstrated that the rate of spin conversion from ortho to para drastically increases from 2.4 × 10^{-4} to 1.7 × 10^{-3} s^{-1} within the very narrow temperature window of 9.2 to16 K. The observed strong temperature cannot be explained by solely state-mixing models ever proposed but by the energy dissipation model via two phonon process. I will present our recent experiments regarding this.

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

Field-to-Fuel Performance Testing of Lignocellulosic Feedstocks for Fast Pyrolysis and Upgrading: Techno-economic Analysis and Greenhouse Gas Life Cycle Analysis

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

Meyer, Pimphan A.; Snowden-Swan, Lesley J.; Rappé, Kenneth G.

This work shows preliminary results from techno-economic analysis and life cycle greenhouse gas analysis of the conversion of seven (7) biomass feedstocks to produce liquid transportation fuels via fast pyrolysis and upgrading via hydrodeoxygenation. The biomass consists of five (5) pure feeds (pine, tulip poplar, hybrid poplar, switchgrass, corn stover) and two blends. Blend 1 consists of equal weights of pine, tulip poplar and switchgrass, and blend 2 is 67% pine and 33% hybrid poplar. Upgraded oil product yield is one of the most significant parameters affecting the process economics, and is a function of both fast pyrolysis oil yieldmore » and hydrotreating oil yield. Pure pine produced the highest overall yield, while switchgrass produced the lowest. Interestingly, herbaceous materials blended with woody biomass performed nearly as well as pure woody feedstock, suggesting a non-trivial relationship between feedstock attributes and production yield. Production costs are also highly dependent upon hydrotreating catalyst-related costs. The catalysts contribute an average of ~15% to the total fuel cost, which can be reduced through research and development focused on achieving performance at increased space velocity (e.g., reduced catalyst loading) and prolonging catalyst lifetime. Green-house-gas reduction does not necessarily align with favorable economics. From the greenhouse gas analysis, processing tulip poplar achieves the largest GHG emission reduction relative to petroleum (~70%) because of its lower hydrogen consumption in the upgrading stage that results in a lower natural gas requirement for hydrogen production. Conversely, processing blend 1 results in the smallest GHG emission reduction from petroleum (~58%) because of high natural gas demand for hydrogen production.« less

Fast Conversion of Ionic Liquids and Poly(Ionic Liquid)s into Porous Nitrogen-Doped Carbons in Air

PubMed Central

Men, Yongjun; Ambrogi, Martina; Han, Baohang; Yuan, Jiayin

2016-01-01

Ionic liquids and poly(ionic liquid)s have been successfully converted into nitrogen-doped porous carbons with tunable surface area up to 1200 m2/g at high temperatures in air. Compared to conventional carbonization process conducted under inert gas to produce nitrogen-doped carbons, the new production method was completed in a rather shorter time without noble gas protection. PMID:27070588

Fast Conversion of Ionic Liquids and Poly(Ionic Liquid)s into Porous Nitrogen-Doped Carbons in Air.

PubMed

Men, Yongjun; Ambrogi, Martina; Han, Baohang; Yuan, Jiayin

2016-04-08

Ionic liquids and poly(ionic liquid)s have been successfully converted into nitrogen-doped porous carbons with tunable surface area up to 1200 m²/g at high temperatures in air. Compared to conventional carbonization process conducted under inert gas to produce nitrogen-doped carbons, the new production method was completed in a rather shorter time without noble gas protection.

Research and evaluation of biomass resources/conversion/utilization systems (market/experimental analysis for development of a data base for a fuels from biomass model. Volume I. Biomass allocation model. Technical progress report for the period ending September 30, 1980

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

Ahn, Y.K.; Chen, H.T.; Helm, R.W.

1980-01-01

A biomass allocation model has been developed to show the most profitable combination of biomass feedstocks thermochemical conversion processes, and fuel products to serve the seasonal conditions in a regional market. This optimization model provides a tool for quickly calculating the most profitable biomass missions from a large number of potential biomass missions. Other components of the system serve as a convenient storage and retrieval mechanism for biomass marketing and thermochemical conversion processing data. The system can be accessed through the use of a computer terminal, or it could be adapted to a portable micro-processor. A User's Manual for themore » system has been included in Appendix A of the report. The validity of any biomass allocation solution provided by the allocation model is dependent on the accuracy of the data base. The initial data base was constructed from values obtained from the literature, and, consequently, as more current thermochemical conversion processing and manufacturing costs and efficiencies become available, the data base should be revised. Biomass derived fuels included in the data base are the following: medium Btu gas low Btu gas, substitute natural gas, ammonia, methanol, electricity, gasoline, and fuel oil. The market sectors served by the fuels include: residential, electric utility, chemical (industrial), and transportation. Regional/seasonal costs and availabilities and heating values for 61 woody and non-woody biomass species are included. The study has included four regions in the United States which were selected because there was both an availability of biomass and a commercial demand for the derived fuels: Region I: NY, WV, PA; Region II: GA, AL, MS; Region III: IN, IL, IA; and Region IV: OR, WA.« less

Hybrid solar cells based on dc magnetron sputtered films of n-ITO on APMOVPE grown p-InP

NASA Technical Reports Server (NTRS)

Coutts, T. J.; Li, X.; Wanlass, M. W.; Emery, K. A.; Gessert, T. A.

1988-01-01

Hybrid indium-tin-oxide (ITO)/InP solar cells are discussed. The cells are constructed by dc magnetron sputter deposition of ITO onto high-quality InP films grown by atmospheric pressure metal-organic vapor-phase epitaxy (APMOVPE). A record efficiency of 18.9 percent, measured under standard Solar Energy Research Institute reporting conditions, has been obtained. The p-InP surface is shown to be type converted, principally by the ITO, but with the extent of conversion being modified by the nature of the sputtering gas. The deposition process, in itself, is not responsible for the type conversion. Dark currents have been suppressed by more than three orders of magnitude by the addition of hydrogen to the sputtering gas during deposition of a thin (5 nm) interface layer. Without this layer, and using only the more usual argon/oxygen mixture, the devices had poorer efficiencies and were unstable. A discussion of associated quantum efficiencies and capacitance/voltage measurements is also presented from which it is concluded that further improvements in efficiency will result from better control over the type-conversion process.

Conceptual process design and economics for the production of high-octane gasoline blendstock via indirect liquefaction of biomass through methanol/dimethyl ether intermediates

DOE PAGES

Tan, Eric C. D.; Talmadge, Michael; Dutta, Abhijit; ...

2015-10-28

This paper describes in detail one potential conversion process for the production of high-octane gasoline blendstock via indirect liquefaction of biomass. The processing steps of this pathway include the conversion of biomass to synthesis gas via indirect gasification, gas clean-up via reforming of tars and other hydrocarbons, catalytic conversion of syngas to methanol, methanol dehydration to dimethyl ether (DME), and the homologation of DME over a zeolite catalyst to high-octane gasoline-range hydrocarbon products. The current process configuration has similarities to conventional methanol-to-gasoline (MTG) technologies, but there are key distinctions, specifically regarding the product slate, catalysts, and reactor conditions. A techno-economicmore » analysis is performed to investigate the production of high-octane gasoline blendstock. The design features a processing daily capacity of 2000 tonnes (2205 short tons) of dry biomass. The process yields 271 liters of liquid fuel per dry tonne of biomass (65 gal/dry ton), for an annual fuel production rate of 178 million liters (47 MM gal) at 90% on-stream time. The estimated total capital investment for an nth-plant is $438 million. The resulting minimum fuel selling price (MFSP) is $0.86 per liter or $3.25 per gallon in 2011 US dollars. A rigorous sensitivity analysis captures uncertainties in costs and plant performance. Sustainability metrics for the conversion process are quantified and assessed. The potential premium value of the high-octane gasoline blendstock is examined and found to be at least as competitive as fossil-derived blendstocks. A simple blending strategy is proposed to demonstrate the potential for blending the biomass-derived blendstock with petroleum-derived intermediates. Published 2015. This article is a U.S. Government work and is in the public domain in the USA. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.« less

Cascaded chirped photon acceleration for efficient frequency conversion

NASA Astrophysics Data System (ADS)

Edwards, Matthew R.; Qu, Kenan; Jia, Qing; Mikhailova, Julia M.; Fisch, Nathaniel J.

2018-05-01

A cascaded sequence of photon acceleration stages using the instantaneous creation of a plasma density gradient by flash ionization allows the generation of coherent and chirped ultraviolet and x-ray pulses with independently tunable frequency and bandwidth. The efficiency of the cascaded process scales with 1/ω in energy, and multiple stages produce significant frequency up-conversion with gas-density plasmas. Chirping permits subsequent pulse compression to few-cycle durations, and output frequencies are not limited to integer harmonics.

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

Study of Catalyst Variation Effect in Glycerol Conversion Process to Hydrogen Gas by Steam Reforming

NASA Astrophysics Data System (ADS)

Widayat; Hartono, R.; Elizabeth, E.; Annisa, A. N.

2018-04-01

Along with the economic development, needs of energy being increase too. Hydrogen as alternative energy has many usages. Besides that, hydrogen is one source of energy that is a clean fuel, but process production of hydrogen from natural gas as a raw material has been used for a long time. Therefore, there is need new invention to produce hydrogen from the others raw material. Glycerol, a byproduct of biodiesel production, is a compound which can be used as a raw material for hydrogen production. By using glycerol as a raw material of hydrogen production, we can get added value of glycerol as well as an energy source solution. The process production of hydrogen by steam reforming is a thermochemical process with efficiency 70%. This process needs contribution of catalyst to improve its efficiency and selectivity of the process. In this study will be examined the effect variation of catalyst for glycerol conversion process to hydrogen by steam reforming. The method for catalyst preparation was variation of catalyst impregnation composition, catalyst calcined with difference concentration of hydrochloric acid and calcined with difference hydrochloric acid ratio. After that, all of catalyst which have been prepared, used for steam reforming process for hydrogen production from glycerol as a raw material. From the study, the highest yield of hydrogen gas showed in the process production by natural zeolite catalyst with 1:15 Hydrochloric acid ratio was 42.28%. Hydrogen yield for 2M calcined natural zeolite catalyst was 38.37%, for ZSM-5 catalyst was 15.83%, for 0.5M calcined natural zeolite was 13.09% and for ultrasonic natural zeolite was 11.43%. The lowest yield of hydrogen gas showed in catalyst 2Zn/ZSM-5 with 11.22%. This result showed that hydrogen yield product was affected by catalyst variation because of the catalyst has difference characteristic and difference catalytic activity after the catalyst preparation process.

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

Tan, Eric; Talmadge, M.; Dutta, Abhijit

The U.S. Department of Energy (DOE) promotes research for enabling cost-competitive liquid fuels production from lignocellulosic biomass feedstocks. The research is geared to advance the state of technology (SOT) of biomass feedstock supply and logistics, conversion, and overall system sustainability. As part of their involvement in this program, the National Renewable Energy Laboratory (NREL) and the Pacific Northwest National Laboratory (PNNL) investigate the economics of conversion pathways through the development of conceptual biorefinery process models. This report describes in detail one potential conversion process for the production of high octane gasoline blendstock via indirect liquefaction (IDL). The steps involve themore » conversion of biomass to syngas via indirect gasification followed by gas cleanup and catalytic syngas conversion to a methanol intermediate; methanol is then further catalytically converted to high octane hydrocarbons. The conversion process model leverages technologies previously advanced by research funded by the Bioenergy Technologies Office (BETO) and demonstrated in 2012 with the production of mixed alcohols from biomass. Biomass-derived syngas cleanup via tar and hydrocarbons reforming was one of the key technology advancements as part of that research. The process described in this report evaluates a new technology area with downstream utilization of clean biomass-syngas for the production of high octane hydrocarbon products through a methanol intermediate, i.e., dehydration of methanol to dimethyl ether (DME) which subsequently undergoes homologation to high octane hydrocarbon products.« less

A finite element simulation of biological conversion processes in landfills.

PubMed

Robeck, M; Ricken, T; Widmann, R

2011-04-01

Landfills are the most common way of waste disposal worldwide. Biological processes convert the organic material into an environmentally harmful landfill gas, which has an impact on the greenhouse effect. After the depositing of waste has been stopped, current conversion processes continue and emissions last for several decades and even up to 100years and longer. A good prediction of these processes is of high importance for landfill operators as well as for authorities, but suitable models for a realistic description of landfill processes are rather poor. In order to take the strong coupled conversion processes into account, a constitutive three-dimensional model based on the multiphase Theory of Porous Media (TPM) has been developed at the University of Duisburg-Essen. The theoretical formulations are implemented in the finite element code FEAP. With the presented calculation concept we are able to simulate the coupled processes that occur in an actual landfill. The model's theoretical background and the results of the simulations as well as the meantime successfully performed simulation of a real landfill body will be shown in the following. Copyright © 2010 Elsevier Ltd. All rights reserved.

Natural Gas and Cellulosic Biomass: A Clean Fuel Combination? Determining the Natural Gas Blending Wall in Biofuel Production.

PubMed

M Wright, Mark; Seifkar, Navid; Green, William H; Román-Leshkov, Yuriy

2015-07-07

Natural gas has the potential to increase the biofuel production output by combining gas- and biomass-to-liquids (GBTL) processes followed by naphtha and diesel fuel synthesis via Fischer-Tropsch (FT). This study reflects on the use of commercial-ready configurations of GBTL technologies and the environmental impact of enhancing biofuels with natural gas. The autothermal and steam-methane reforming processes for natural gas conversion and the gasification of biomass for FT fuel synthesis are modeled to estimate system well-to-wheel emissions and compare them to limits established by U.S. renewable fuel mandates. We show that natural gas can enhance FT biofuel production by reducing the need for water-gas shift (WGS) of biomass-derived syngas to achieve appropriate H2/CO ratios. Specifically, fuel yields are increased from less than 60 gallons per ton to over 100 gallons per ton with increasing natural gas input. However, GBTL facilities would need to limit natural gas use to less than 19.1% on a LHV energy basis (7.83 wt %) to avoid exceeding the emissions limits established by the Renewable Fuels Standard (RFS2) for clean, advanced biofuels. This effectively constitutes a blending limit that constrains the use of natural gas for enhancing the biomass-to-liquids (BTL) process.

Adiabatic burst evaporation from bicontinuous nanoporous membranes

PubMed Central

Ichilmann, Sachar; Rücker, Kerstin; Haase, Markus; Enke, Dirk

2015-01-01

Evaporation of volatile liquids from nanoporous media with bicontinuous morphology and pore diameters of a few 10 nm is an ubiquitous process. For example, such drying processes occur during syntheses of nanoporous materials by sol–gel chemistry or by spinodal decomposition in the presence of solvents as well as during solution impregnation of nanoporous hosts with functional guests. It is commonly assumed that drying is endothermic and driven by non-equilibrium partial pressures of the evaporating species in the gas phase. We show that nearly half of the liquid evaporates in an adiabatic mode involving burst-like liquid-to-gas conversions. During single adiabatic burst evaporation events liquid volumes of up to 107 μm3 are converted to gas. The adiabatic liquid-to-gas conversions occur if air invasion fronts get unstable because of the built-up of high capillary pressures. Adiabatic evaporation bursts propagate avalanche-like through the nanopore systems until the air invasion fronts have reached new stable configurations. Adiabatic cavitation bursts thus compete with Haines jumps involving air invasion front relaxation by local liquid flow without enhanced mass transport out of the nanoporous medium and prevail if the mean pore diameter is in the range of a few 10 nm. The results reported here may help optimize membrane preparation via solvent-based approaches, solution-loading of nanopore systems with guest materials as well as routine use of nanoporous membranes with bicontinuous morphology and may contribute to better understanding of adsorption/desorption processes in nanoporous media. PMID:25926406

Final technical report for the Center for Catalytic Hydrocarbon Functionalization (an EFRC)

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

Gunnoe, Thomas Brent

Greater than 95% of all materials produced by the chemical industry are derived from a small slate of simple hydrocarbons that are derived primarily from natural gas and petroleum, predominantly through oxygenation, C–C bond formation, halogenation or amination. Yet, current technologies for hydrocarbon conversion are typically high temperature, multi-step processes that are energy and capital intensive and result in excessive emissions (including carbon dioxide). The Center for Catalytic Hydrocarbon Functionalization (CCHF) brought together research teams with the broad coalition of skills and knowledge needed to make the fundamental advances in catalysis required for next-generation technologies to convert hydrocarbons (particularly lightmore » alkanes and methane) at high efficiency and low cost. Our new catalyst technologies offer many opportunities including enhanced utilization of natural gas in the transportation sector (via conversion to liquid fuels), more efficient generation of electricity from natural gas using direct methane fuel cells, reduced energy consumption and waste production for large petrochemical processes, and the preparation of high value molecules for use in biological/medical applications or the agricultural sector. The five year collaborative project accelerated fundamental understanding of catalyst design for the conversion of C–H bonds to functionalized products, essential to achieve the goals listed above, as evidenced by the publication of 134 manuscripts. Many of these fundamental advancements provide a foundation for potential commercialization, as evidenced by the submission of 11 patents from research support by the CCHF.« less

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.

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.

Dry reforming of methane via plasma-catalysis: influence of the catalyst nature supported on alumina in a packed-bed DBD configuration

NASA Astrophysics Data System (ADS)

Brune, L.; Ozkan, A.; Genty, E.; Visart de Bocarmé, T.; Reniers, F.

2018-06-01

These days, the consideration of CO2 as a feedstock has become the subject of more interest. The reutilization of CO2 is already possible via cold plasma techniques operating at atmospheric pressure. A promising technology is the dielectric barrier discharge (DBD). In most cases DBDs exhibit a low energy efficiency for CO2 conversion. However, several routes can be used to increase this efficiency and hence, the product formation. One of these routes is the packed-bed DBD configuration with porous beads inside the gap of the DBD, which also allows the coupling of plasma with catalysis. Catalysts can be introduced in such a configuration to exploit the synergistic effect between plasma and catalytically active surfaces, leading to a more efficient process. In this article, the dry reforming of methane (DRM) is studied, which aims to convert both CO2 and CH4, another greenhouse gas, at the same time. The conversions and energy costs of the DRM process are investigated and compared in both the packed-bed DBD configurations containing catalysts (Co, Cu or Ni) and the classical DBD. The change in filamentary behavior is studied in detail and correlated with the obtained conversions using gas chromatography, mass spectrometry and using an oscilloscope. A characterization of the catalysts on the beads is also carried out. Both the CO2 and CH4 conversions are clearly increased with the plasma-catalysis. Moreover, CH4 conversions as high as 90% can be obtained in certain conditions with copper catalysts.

An Investigation of the Reverse Water Gas Shift Process and Operating Alternatives

NASA Technical Reports Server (NTRS)

Whitlow, Jonathan E.

2002-01-01

The Reverse Water Gas Shift (RWGS) process can produce water and ultimately oxygen through electrolysis. This technology is being investigated for possible use in the exploration of Mars as well as a potential process to aid in the regeneration of oxygen from carbon dioxide. The initial part of this report summarizes the results obtained from operation of the RWGS process at Kennedy Space Center during May and June of this year. It has been demonstrated that close to complete conversion can be achieved with the RWGS process under certain operating conditions. The report also presents results obtained through simulation for an alternative staged configuration for RWGS which eliminates the recycle compressor. This configuration looks promising and hence seems worthy of experimental investigation.

Development of compact fuel processor for 2 kW class residential PEMFCs

NASA Astrophysics Data System (ADS)

Seo, Yu Taek; Seo, Dong Joo; Jeong, Jin Hyeok; Yoon, Wang Lai

Korea Institute of Energy Research (KIER) has been developing a novel fuel processing system to provide hydrogen rich gas to residential polymer electrolyte membrane fuel cells (PEMFCs) cogeneration system. For the effective design of a compact hydrogen production system, the unit processes of steam reforming, high and low temperature water gas shift, steam generator and internal heat exchangers are thermally and physically integrated into a packaged hardware system. Several prototypes are under development and the prototype I fuel processor showed thermal efficiency of 73% as a HHV basis with methane conversion of 81%. Recently tested prototype II has been shown the improved performance of thermal efficiency of 76% with methane conversion of 83%. In both prototypes, two-stage PrOx reactors reduce CO concentration less than 10 ppm, which is the prerequisite CO limit condition of product gas for the PEMFCs stack. After confirming the initial performance of prototype I fuel processor, it is coupled with PEMFC single cell to test the durability and demonstrated that the fuel processor is operated for 3 days successfully without any failure of fuel cell voltage. Prototype II fuel processor also showed stable performance during the durability test.

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.

The ratio of molecular to atomic gas in spiral galaxies as a function of morphological type

NASA Technical Reports Server (NTRS)

Knezek, Patricia M.; Young, Judith S.

1990-01-01

In order to gain an understanding of the global processes which influence cloud and star formation in disk galaxies, it is necessary to determine the relative amounts of atomic, molecular, and ionized gas both as a function of position in galaxies and from galaxy to galaxy. With observations of the CO distributions in over 200 galaxies now completed as part of the Five College Radio Astronomy Observatory (FCRAO) Extragalactic CO Survey (Young et al. 1989), researchers are finally in a position to determine the type dependence of the molecular content of spiral galaxies, along with the ratio of molecular to atomic gas as a function of type. Do late type spirals really have more gas than early types when the molecular gas content is included. Researchers conclude that there is more than an order of magnitude decrease in the ratio of molecular to atomic gas mass as a function of morphological type from Sa-Sd; an average Sa galaxy has more molecular than atomic gas, and an average Sc has less. Therefore, the total interstellar gas mass to blue luminosity ratio, M sub gas/L sub B, increases by less than a factor of two as a function of type from Sa-Sd. The dominant effect found is that the phase of the gas in the cool interstellar medium (ISM) varies along the Hubble sequence. Researchers suggest that the more massive and centrally concentrated galaxies are able to achieve a molecular-dominated ISM through the collection of more gas in the potential. That gas may then form molecular clouds when a critical density is exceeded. The picture which these observations support is one in which the conversion of atomic gas to molecular gas is a global process which depends on large scale dynamics (cf Wyse 1986). Among interacting and merging systems, researchers find considerable scatter in the M(H2)/M(HI) ratio, with the mean ratio similar to that in the early type galaxies. The high global ratio of molecular to atomic gas could result from the removal of HI gas, the enhanced conversion of HI into H2, or both.

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.

Cogeneration Technology Alternatives Study (CTAS). Volume 3: Energy conversion system characteristics

NASA Technical Reports Server (NTRS)

1980-01-01

Six current and thirty-six advanced energy conversion systems were defined and combined with appropriate balance of plant equipment. Twenty-six industrial processes were selected from among the high energy consuming industries to serve as a frame work for the study. Each conversion system was analyzed as a cogenerator with each industrial plant. Fuel consumption, costs, and environmental intrusion were evaluated and compared to corresponding traditional values. The advanced energy conversion technologies indicated reduced fuel consumption, costs, and emissions. Fuel energy savings of 10 to 25 percent were predicted compared to traditional on site furnaces and utility electricity. With the variety of industrial requirements, each advanced technology had attractive applications. Fuel cells indicated the greatest fuel energy savings and emission reductions. Gas turbines and combined cycles indicated high overall annual savings. Steam turbines and gas turbines produced high estimated returns. In some applications, diesels were most efficient. The advanced technologies used coal derived fuels, or coal with advanced fluid bed combustion or on site gasifications. Data and information for both current and advanced energy conversion technology are presented. Schematic and physical descriptions, performance data, equipment cost estimates, and predicted emissions are included. Technical developments which are needed to achieve commercialization in the 1985-2000 period are identified.

Energy and cost savings results for advanced technology systems from the Cogeneration Technology Alternatives Study /CTAS/

NASA Technical Reports Server (NTRS)

Sagerman, G. D.; Barna, G. J.; Burns, R. K.

1979-01-01

The Cogeneration Technology Alternatives Study (CTAS), a program undertaken to identify the most attractive advanced energy conversion systems for industrial cogeneration applications in the 1985-2000 time period, is described, and preliminary results are presented. Two cogeneration options are included in the analysis: a topping application, in which fuel is input to the energy conversion system which generates electricity and waste heat from the conversion system is used to provide heat to the process, and a bottoming application, in which fuel is burned to provide high temperature process heat and waste heat from the process is used as thermal input to the energy conversion system which generates energy. Steam turbines, open and closed cycle gas turbines, combined cycles, diesel engines, Stirling engines, phosphoric acid and molten carbonate fuel cells and thermionics are examined. Expected plant level energy savings, annual energy cost savings, and other results of the economic analysis are given, and the sensitivity of these results to the assumptions concerning fuel prices, price of purchased electricity and the potential effects of regional energy use characteristics is discussed.

Energy Conversion in Natural and Artificial Photosynthesis

PubMed Central

McConnell, Iain; Li, Gonghu; Brudvig, Gary W.

2010-01-01

Summary Modern civilization is dependent upon fossil fuels, a nonrenewable energy source originally provided by the storage of solar energy. Fossil fuel dependence has severe consequences including energy security issues and greenhouse gas emissions. The consequences of fossil fuel dependence could be avoided by fuel-producing artificial systems that mimic natural photosynthesis, directly converting solar energy to fuel. This review describes the three key components of solar energy conversion in photosynthesis: light harvesting, charge separation, and catalysis. These processes are compared in natural and artificial systems. Such a comparison can assist in understanding the general principles of photosynthesis and in developing working devices including photoelectrochemical cells for solar energy conversion. PMID:20534342

Fossil fuel combined cycle power generation method

DOEpatents

Labinov, Solomon D [Knoxville, TN; Armstrong, Timothy R [Clinton, TN; Judkins, Roddie R [Knoxville, TN

2008-10-21

A method for converting fuel energy to electricity includes the steps of converting a higher molecular weight gas into at least one mixed gas stream of lower average molecular weight including at least a first lower molecular weight gas and a second gas, the first and second gases being different gases, wherein the first lower molecular weight gas comprises H.sub.2 and the second gas comprises CO. The mixed gas is supplied to at least one turbine to produce electricity. The mixed gas stream is divided after the turbine into a first gas stream mainly comprising H.sub.2 and a second gas stream mainly comprising CO. The first and second gas streams are then electrochemically oxidized in separate fuel cells to produce electricity. A nuclear reactor can be used to supply at least a portion of the heat the required for the chemical conversion process.

Rapid Response Research and Development (R&D) for the Aerospace Systems Directorate. Delivery Order 0021: Engineering Research and Technical Analyses of Advanced Airbreathing Propulsion Fuels, Subtask: Fit-for-Purpose (FFP) and Dynamic Seal Testing of Alternative Aviation Fuels

DTIC Science & Technology

2014-08-01

of alcohols with LanzaTech’s unique gas fermentation process for converting waste gas streams to ethanol. The alcohol conversion process begins with...grain/wood being converted to sugar followed by fermentation into a mixture of C2-C5 alcohols. These are then converted to a mixture of C4-C20...produce farnesene by fermentation of sugar feedstocks. Farnesene is then converted to farnesane through a combination of hydroprocessing and

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

78 FR 37215 - Tallgrass Interstate Gas Transmission, LLC; Notice of Availability of the Environmental...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-20

... Pony Express Pipeline Conversion Project The staff of the Federal Energy Regulatory Commission (FERC or Commission) has prepared an environmental assessment (EA) of the Pony Express Pipeline Conversion Project (PXP Conversion Project) proposed by Tallgrass Interstate Gas Transmission, LLC, (TIGT) formerly known...

75 FR 14590 - Petal Gas Storage, L.L.C.; Notice of Intent To Prepare an Environmental Assessment for the...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-26

... Conversion Gas Storage Project and Request for Comments on Environmental Issues March 19, 2010. The staff of... (EA) that will discuss the environmental impacts of the Cavern 12A Conversion Gas Storage Project...

Impact of feedstock quality and variation on biochemical and thermochemical conversion

DOE PAGES

Li, Chenlin; Aston, John E.; Lacey, Jeffrey A.; ...

2016-07-21

The production of biofuels from lignocellulosic feedstock is attracting considerable attention in the United States and globally as a strategy to diversify energy resources, spur regional economic development and reduce greenhouse gas emissions. Because of the wide variation in feedstock types, compositions and content of convertible organics, there is a growing need to better understand correlations among feedstock quality attributes and conversion performance. Knowledge of the feedstock impact on conversion is essential to supply quality controlled, uniform and on-spec feedstocks to biorefineries. This review paper informs the development of meaningful feedstock quality specifications for different conversion processes. Discussions are focusedmore » on how compositional properties of feedstocks affect various unit operations in biochemical conversion processes, fast pyrolysis and hydrothermal liquefaction. In addition, future perspectives are discussed that focus on the challenges and prospects of addressing compositionally intrinsic inhibitors through feedstock preprocessing at regionally distributed depots. As a result, such preprocessing depots may allow for the commoditization of lignocellulosic feedstock and realization of stable, cost-effective and quality controlled biomass supply systems.« less

Thermocatalytic Destruction of Gas-Phase Perchloroethylene Using Propane as a Hydrogen Source

PubMed Central

Willinger, Marty; Rupp, Erik; Barbaris, Brian; Gao, Song; Arnolda, Robert; Betterton, Eric; Sáez, A. Eduardo

2009-01-01

The use of propane in combination with oxygen to promote the destruction of perchloroethylene (PCE) over a platinum (Pt)/rhodium (Rh) catalyst on a cerium/zirconium oxide washcoat supported on an alumina monolith was explored. Conversions of PCE were measured in a continuous flow reactor with residence times less than 0.5 s and temperatures ranging from 200 to 600°C. The presence of propane was shown to increase significantly the conversion of PCE over oxygen-only conditions. Conversions close to 100% were observed at temperatures lower than 450°C with 20% oxygen and 2% propane in the feed, which makes this process attractive from a practical standpoint. In the absence of oxygen, PCE conversion is even higher, but the catalyst suffers significant deactivation in less than an hour. Even though results show that oxygen competes with reactants for active sites on the catalyst, the long-term stability that oxygen confers to the catalyst makes the process an efficient alternative to PCE oxidation. A Langmuir-Hinshelwood competitive adsorption model is proposed to quantify PCE conversion. PMID:19217713

Impact of feedstock quality and variation on biochemical and thermochemical conversion

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

Li, Chenlin; Aston, John E.; Lacey, Jeffrey A.

The production of biofuels from lignocellulosic feedstock is attracting considerable attention in the United States and globally as a strategy to diversify energy resources, spur regional economic development and reduce greenhouse gas emissions. Because of the wide variation in feedstock types, compositions and content of convertible organics, there is a growing need to better understand correlations among feedstock quality attributes and conversion performance. Knowledge of the feedstock impact on conversion is essential to supply quality controlled, uniform and on-spec feedstocks to biorefineries. This review paper informs the development of meaningful feedstock quality specifications for different conversion processes. Discussions are focusedmore » on how compositional properties of feedstocks affect various unit operations in biochemical conversion processes, fast pyrolysis and hydrothermal liquefaction. In addition, future perspectives are discussed that focus on the challenges and prospects of addressing compositionally intrinsic inhibitors through feedstock preprocessing at regionally distributed depots. As a result, such preprocessing depots may allow for the commoditization of lignocellulosic feedstock and realization of stable, cost-effective and quality controlled biomass supply systems.« less

Techno-economic feasibility and life cycle assessment of dairy effluent to renewable diesel via hydrothermal liquefaction.

PubMed

Summers, Hailey M; Ledbetter, Rhesa N; McCurdy, Alex T; Morgan, Michael R; Seefeldt, Lance C; Jena, Umakanta; Hoekman, S Kent; Quinn, Jason C

2015-11-01

The economic feasibility and environmental impact is investigated for the conversion of agricultural waste, delactosed whey permeate, through yeast fermentation to a renewable diesel via hydrothermal liquefaction. Process feasibility was demonstrated at laboratory-scale with data leveraged to validate systems models used to perform industrial-scale economic and environmental impact analyses. Results show a minimum fuel selling price of $4.78 per gallon of renewable diesel, a net energy ratio of 0.81, and greenhouse gas emissions of 30.0g-CO2-eqMJ(-1). High production costs and greenhouse gas emissions can be attributed to operational temperatures and durations of both fermentation and hydrothermal liquefaction. However, high lipid yields of the yeast counter these operational demands, resulting in a favorable net energy ratio. Results are presented on the optimization of the process based on economy of scale and a sensitivity analysis highlights improvements in conversion efficiency, yeast biomass productivity and hydrotreating efficiency can dramatically improve commercial feasibility. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

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.

Effects of alternate fuels. Report No. 2. Analysis of basic refractories degraded by residual oil combustion products

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

Wei, G. C.; Tennery, V. J.

1978-02-01

Industrial conversion in the U.S. to alternate fuels from natural gas is presently under way and will accelerate rapidly as a result of gas curtailments and National policy considerations. Currently the prime alternate fuels are distillate and residual oils and coal. Conversion to residual oils or coal for high-temperature process heat applications is anticipated to result in accelerated refractory and insulation corrosion and degradation due to reactions between fuel impurities and the ceramic linings of high-temperature equipment. Understanding the nature of such reactions and identification of means for preventing or retarding them will be of considerable assistance to both refractorymore » manufacturers and users as well as a significant contribution to energy conservation.« less

Stability of the dithiocarbamate pesticide maneb in tomato homogenates during cold storage and thermal processing.

PubMed

Kontou, S; Tsipi, D; Tzia, C

2004-11-01

The effect of storage at 5 degrees C and of thermal processing by cooking at 100 degrees C and sterilization at 121 degrees C for 15 min on maneb residues in tomato homogenates was investigated. Remaining maneb and its toxic metabolite ethylenethiourea (ETU) were measured after each treatment by headspace gas chromatography with flame-photometric detection and by high-performance liquid chromatography with photo-diode array detection, respectively. No significant loss of maneb was observed during cold storage for up to 6 weeks, taking into account analytical variability. Conversely, thermal treatment resulted in substantial degradation of maneb with extensive conversion to ETU. After cooking, only 26 +/- 1% (+/- SE, n = 8) of initial maneb residues remained in the samples, whilst the conversion to ETU was 28 +/- 1% (mol mol(-1)) (+/- SE, n = 4). Sterilization eliminated the residues of the parent compound giving rise to conversion to ETU up to 32 +/- 1% (mol mol(-1)) (+/- SE, n = 4).

Reversible thermodynamic cycle for AMTEC power conversion. [Alkali Metal Thermal-to-Electric Converter

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

Vining, C.B.; Williams, R.M.; Underwood, M.L.

1993-10-01

An AMTEC cell, may be described as performing two distinct energy conversion processes: (i) conversion of heat to mechanical energy via a sodium-based heat engine and (ii) conversion of mechanical energy to electrical energy by utilizing the special properties of the electrolyte material. The thermodynamic cycle appropriate to an alkali metal thermal-to-electric converter cell is discussed for both liquid- and vapor-fed modes of operation, under the assumption that all processes can be performed reversibly. In the liquid-fed mode, the reversible efficiency is greater than 89.6% of Carnot efficiency for heat input and rejection temperatures (900--1,300 and 400--800 K, respectively) typicalmore » of practical devices. Vapor-fed cells can approach the efficiency of liquid-fed cells. Quantitative estimates confirm that the efficiency is insensitive to either the work required to pressurize the sodium liquid or the details of the state changes associated with cooling the low pressure sodium gas to the heat rejection temperature.« less

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.

Catalyst and process for converting synthesis gas to liquid motor fuels

DOEpatents

Coughlin, Peter K.

1987-01-01

The addition of an inert metal component, such as gold, silver or copper, to a Fischer-Tropsch catalyst comprising cobalt enables said catalyst to convert synthesis gas to liquid motor fuels at about 240.degree.-370.degree. C. with advantageously reduced selectivity of said cobalt for methane in said conversion. The catalyst composition can advantageously include a support component, such as a molecular sieve, co-catalyst/support component or a combination of such support components.

Utilization of methanol for polymer electrolyte fuel cells in mobile systems

NASA Astrophysics Data System (ADS)

Schmidt, V. M.; Brockerhoff, P.; Hohlein, B.; Menzer, R.; Stimming, U.

1994-04-01

The constantly growing volume of road traffic requires the introduction of new vehicle propulsion systems with higher efficiency and drastically reduced emission rates. As part of the fuel cell programme of the Research Centre Julich a vehicle propulsion system with methanol as secondary energy carrier and a polymer electrolyte membrane fuel cell (PEMFC) as the main component for energy conversion is developed. The fuel gas is produced by a heterogeneously catalyzed steam reforming reaction in which methanol is converted to H2, CO and CO2. The required energy is provided by the catalytic conversion of methanol for both heating up the system and reforming methanol. The high CO content of the fuel gas requires further processing of the gas or the development of new electrocatalysts for the anode. Various Pt-Ru alloys show promising behaviour as CO-tolerant anodes. The entire fuel cell system is discussed in terms of energy and emission balances. The development of important components is described and experimental results are discussed.

On-board diesel autothermal reforming for PEM fuel cells: Simulation and optimization

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

Cozzolino, Raffaello, E-mail: raffaello.cozzolino@unicusano.it; Tribioli, Laura

2015-03-10

Alternative power sources are nowadays the only option to provide a quick response to the current regulations on automotive pollutant emissions. Hydrogen fuel cell is one promising solution, but the nature of the gas is such that the in-vehicle conversion of other fuels into hydrogen is necessary. In this paper, autothermal reforming, for Diesel on-board conversion into a hydrogen-rich gas suitable for PEM fuel cells, has investigated using the simulation tool Aspen Plus. A steady-state model has been developed to analyze the fuel processor and the overall system performance. The components of the fuel processor are: the fuel reforming reactor,more » two water gas shift reactors, a preferential oxidation reactor and H{sub 2} separation unit. The influence of various operating parameters such as oxygen to carbon ratio, steam to carbon ratio, and temperature on the process components has been analyzed in-depth and results are presented.« less

Melter feed viscosity during conversion to glass: Comparison between low-activity waste and high-level waste feeds

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

Jin, Tongan; Chun, Jaehun; Dixon, Derek R.

During nuclear waste vitrification, a melter feed (generally a slurry-like mixture of a nuclear waste and various glass forming and modifying additives) is charged into the melter where undissolved refractory constituents are suspended together with evolved gas bubbles from complex reactions. Knowledge of flow properties of various reacting melter feeds is necessary to understand their unique feed-to-glass conversion processes occurring within a floating layer of melter feed called a cold cap. The viscosity of two low-activity waste (LAW) melter feeds were studied during heating and correlated with volume fractions of undissolved solid phase and gas phase. In contrast to themore » high-level waste (HLW) melter feed, the effects of undissolved solid and gas phases play comparable roles and are required to represent the viscosity of LAW melter feeds. This study can help bring physical insights to feed viscosity of reacting melter feeds with different compositions and foaming behavior in nuclear waste vitrification.« less

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.

Reduction of Greenhouse Gas and Criteria Pollutant Emissions by Direct Conversion of Associated Flare Gas to Synthetic Fuels at Oil Wellheads

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

Tan, Eric C; Zhang, Yi Min; Schuetzle, Dennis

This study describes the results of a 'well-to-wheel' life cycle assessment (LCA) carried out to determine the potential greenhouse gas and criteria pollutant emission reductions that could be achieved by converting associated flare gas directly to synthetic fuels at oil wellheads in the US and globally. A Greyrock Flare Gas-to-Fuels(TM) conversion process at an Ohio oil well was used as the base case for this LCA. The liquid fuel produced directly from associated gas is comprised primarily of premium synthetic diesel with a small amount of synthetic gasoline. In this LCA scenario, the synthetic diesel and synthetic gasoline are blendedmore » at 20 and 10 vol% with petroleum diesel and gasoline, respectively. While the synthetic diesel fuel can be used as is (100%), the 20 vol% synthetic diesel blend (with petroleum diesel) was found to significantly improve engine performance, increase fuel economy, and reduce emissions. The direct conversion of associated gas to synthetic diesel fuels globally could reduce emissions of CO2 and CH4 by up to 356 and 5.96 million metric tons/year, respectively, resulting in the reduction of greenhouse gases (GHGs) by about 113.3 and 92.2% (20 year global warming potential) and 73.8 and 50.7% (100 year global warming potential) for synthetic diesel and gasoline fuels when compared to petroleum-derived gasoline fuels, respectively. Likewise, diesel criteria emissions could be reduced globally by up to 23.3, 0.374, 42.4, and 61.3 million metric tons/year globally for CO, particulates, NOx, and hydrocarbons, respectively. The potential economic benefit of this approach is that up to 5.30 and 71.1 billion liters of synthetic fuels could be produced each year in the US and globally from associated gas, respectively.« less

Fossil fuel combined cycle power system

DOEpatents

Labinov, Solomon Davidovich; Armstrong, Timothy Robert; Judkins, Roddie Reagan

2006-10-10

A system for converting fuel energy to electricity includes a reformer for converting a higher molecular weight gas into at least one lower molecular weight gas, at least one turbine to produce electricity from expansion of at least one of the lower molecular weight gases, and at least one fuel cell. The system can further include at least one separation device for substantially dividing the lower molecular weight gases into at least two gas streams prior to the electrochemical oxidization step. A nuclear reactor can be used to supply at least a portion of the heat the required for the chemical conversion process.

Energy transfer model and its applications of ultrasonic gas flow-meter under static and dynamic flow rates

NASA Astrophysics Data System (ADS)

Fang, Min; Xu, Ke-Jun; Zhu, Wen-Jiao; Shen, Zi-Wen

2016-01-01

Most of the ultrasonic gas flow-meters measure the gas flow rate by calculating the ultrasonic transmission time difference between the downstream and upstream. Ultrasonic energy attenuation occurs in the processes of the ultrasonic generation, conversion, transmission, and reception. Additionally, at the same time, the gas flow will also affect the ultrasonic propagation during the measurement, which results in the ultrasonic energy attenuation and the offset of ultrasonic propagation path. Thus, the ultrasonic energy received by the transducer is weaker. When the gas flow rate increases, this effect becomes more apparent. It leads to the measurement accuracy reduced, and the measurement range narrowed. An energy transfer model, where the ultrasonic gas flow-meter under without/with the gas flow, is established by adopting the statistical analysis and curve fitting based on a large amount of experimental data. The static sub model without the gas flow expresses the energy conversion efficiency of ultrasonic gas transducers, and the dynamic sub model with the gas flow reflects the energy attenuation pattern following the flow rate variations. The mathematical model can be used to determine the minimum energy of the excitation signal for meeting the requirement of specific measurement range, and predict the maximum measurable flow rate in the case of fixed energy of excitation signal. Based on the above studies, a method to enhance the excitation signal energy is proposed under the output power of the transmitting circuit being a finite value so as to extend the measurement rage of ultrasonic gas flow-meter.

77 FR 60981 - Kinder Morgan Interstate Gas Transmission L.L.C.; Notice of Intent To Prepare an Environmental...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-05

... Pony Express Pipeline Conversion Project and Request for Comments on Environmental Issues The staff of... (EA) that will discuss the environmental impacts of the Pony Express Pipeline Conversion Project involving conversion of facilities from natural gas to oil and construction and operation of new facilities...

Coke formation and carbon atom economy of methanol-to-olefins reaction.

PubMed

Wei, Yingxu; Yuan, Cuiyu; Li, Jinzhe; Xu, Shutao; Zhou, You; Chen, Jingrun; Wang, Quanyi; Xu, Lei; Qi, Yue; Zhang, Qing; Liu, Zhongmin

2012-05-01

The methanol-to-olefins (MTO) process is becoming the most important non-petrochemical route for the production of light olefins from coal or natural gas. Maximizing the generation of the target products, ethene and propene, and minimizing the production of byproducts and coke, are major considerations in the efficient utilization of the carbon resource of methanol. In the present work, the heterogeneous catalytic conversion of methanol was evaluated by performing simultaneous measurements of the volatile products generated in the gas phase and the confined coke deposition in the catalyst phase. Real-time and complete reaction profiles were plotted to allow the comparison of carbon atom economy of methanol conversion over the catalyst SAPO-34 at varied reaction temperatures. The difference in carbon atom economy was closely related with the coke formation in the SAPO-34 catalyst. The confined coke compounds were determined. A new type of confined organics was found, and these accounted for the quick deactivation and low carbon atom economy under low-reaction-temperature conditions. Based on the carbon atom economy evaluation and coke species determination, optimized operating conditions for the MTO process are suggested; these conditions guarantee high conversion efficiency of methanol. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

Laser beam heat method reported

NASA Astrophysics Data System (ADS)

Tsuchiya, Hachiro; Goto, Hidekazu

1988-07-01

An outline of research involving the processing method utilizing laser-induced thermochemistry was presented, with the CO2 laser processing of ceramics in CF4 gas used as a practical processing example. It has become clear that it will be possible to conduct laser proccessing of ceramics with high efficiency and high precision by utilizing the thermochemical processes, but it is not believed that the present method is the best one and it is not clear that it can be applied to commercial processing. It is thought that the processing characteristics of this method will be greatly changed by the combination of the atmospheric gas and the material, and it is important to conduct tests on various combinations. However, it is believed that the improvement and development will become possible by theoretically confirming the basic process of the processing, especially of the the thermochemical process between the solid surface and the atmospheric gas molecule. Actually, it is believed that the thermochemical process on the solid surface is quite complicated. For example, it was confirmed that when thermochemical processing the Si monocrystal in the CF4 gas, the processing speed would change by at least 10 times through changing the gas pressure and the mixing O2 gas density. However, conversely speaking, it is believed that the fact that this method is complicated, with many unexplained points and room for research, conceals the possibility of its being applied to various fields, and also, in this sense, the quantitative confirmation of its basic process in an important problem to be solved in the future.

10 CFR Appendix J to Part 110 - Illustrative List of Uranium Conversion Plant Equipment and Plutonium Conversion Plant Equipment...

Code of Federal Regulations, 2013 CFR

2013-01-01

... cracked ammonia gas or hydrogen. (4) Especially Designed or Prepared Systems for the conversion of UO2 to UF4. Conversion of UO2 to UF4 can be performed by reacting UO2 with hydrogen fluoride gas (HF) at 300... hydrolyzed to UO2 using hydrogen and steam. In the second, UF6 is hydrolyzed by solution in water, ammonia is...

10 CFR Appendix J to Part 110 - Illustrative List of Uranium Conversion Plant Equipment and Plutonium Conversion Plant Equipment...

Code of Federal Regulations, 2012 CFR

2012-01-01

... cracked ammonia gas or hydrogen. (4) Especially Designed or Prepared Systems for the conversion of UO2 to UF4. Conversion of UO2 to UF4 can be performed by reacting UO2 with hydrogen fluoride gas (HF) at 300... UO2 using hydrogen and steam. In the second, UF6 is hydrolyzed by solution in water, ammonia is added...

10 CFR Appendix J to Part 110 - Illustrative List of Uranium Conversion Plant Equipment and Plutonium Conversion Plant Equipment...

Code of Federal Regulations, 2014 CFR

2014-01-01

... cracked ammonia gas or hydrogen. (4) Especially Designed or Prepared Systems for the conversion of UO2 to UF4. Conversion of UO2 to UF4 can be performed by reacting UO2 with hydrogen fluoride gas (HF) at 300... hydrolyzed to UO2 using hydrogen and steam. In the second, UF6 is hydrolyzed by solution in water, ammonia is...

Advanced Hydrogen Liquefaction Process

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

Schwartz, Joseph; Kromer, Brian; Neu, Ben

2011-09-28

The project identified and quantified ways to reduce the cost of hydrogen liquefaction, and reduce the cost of hydrogen distribution. The goal was to reduce the power consumption by 20% and then to reduce the capital cost. Optimizing the process, improving process equipment, and improving ortho-para conversion significantly reduced the power consumption of liquefaction, but by less than 20%. Because the efficiency improvement was less than the target, the program was stopped before the capital cost was addressed. These efficiency improvements could provide a benefit to the public to improve the design of future hydrogen liquefiers. The project increased themore » understanding of hydrogen liquefaction by modeling different processes and thoroughly examining ortho-para separation and conversion. The process modeling provided a benefit to the public because the project incorporated para hydrogen into the process modeling software, so liquefaction processes can be modeled more accurately than using only normal hydrogen. Adding catalyst to the first heat exchanger, a simple method to reduce liquefaction power, was identified, analyzed, and quantified. The demonstrated performance of ortho-para separation is sufficient for at least one identified process concept to show reduced power cost when compared to hydrogen liquefaction processes using conventional ortho-para conversion. The impact of improved ortho-para conversion can be significant because ortho para conversion uses about 20-25% of the total liquefaction power, but performance improvement is necessary to realize a substantial benefit. Most of the energy used in liquefaction is for gas compression. Improvements in hydrogen compression will have a significant impact on overall liquefier efficiency. Improvements to turbines, heat exchangers, and other process equipment will have less impact.« less

Technical, economic, and environmental impact study of converting Uzbekistan transportation fleets to natural gas operation. Export trade information

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

NONE

1997-04-30

This study, conducted by Radian International, was funded by the U.S. Trade and Development Agency. The report assesses the feasibility (technical, economic and environmental) of converting the Uzbek transportation fleets to natural gas operation. The study focuses on the conversion of high fuel use vehicles and locomotives to liquefied natural gas (LNG) and the conversion of moderate fuel use veicles to compressed natural gas (CNG). The report is divided into the following sections: Executive Summary; (1.0) Introduction; (2.0) Country Background; (3.0) Characterization of Uzbek Transportation Fuels; (4.0) Uzbek Vehicle and Locomotive Fleet Characterization; (5.0) Uzbek Natural Gas Vehicle Conversion Shops;more » (6.0) Uzbek Natural Gas Infrastructure; (7.0) Liquefied Natural Gas (LNG) for Vehicular Fuel in Uzbekistan; (8.0) Economic Feasibility Study; (9.0) Environmental Impact Analysis; References; Appendices A - S.« less

Centrifugal Gas Compression Cycle

NASA Astrophysics Data System (ADS)

Fultun, Roy

2002-11-01

A centrifuged gas of kinetic, elastic hard spheres compresses isothermally and without flow of heat in a process that reverses free expansion. This theorem follows from stated assumptions via a collection of thought experiments, theorems and other supporting results, and it excludes application of the reversible mechanical adiabatic power law in this context. The existence of an isothermal adiabatic centrifugal compression process makes a three-process cycle possible using a fixed sample of the working gas. The three processes are: adiabatic mechanical expansion and cooling against a piston, isothermal adiabatic centrifugal compression back to the original volume, and isochoric temperature rise back to the original temperature due to an influx of heat. This cycle forms the basis for a Thomson perpetuum mobile that induces a loop of energy flow in an isolated system consisting of a heat bath connectable by a thermal path to the working gas, a mechanical extractor of the gas's internal energy, and a device that uses that mechanical energy and dissipates it as heat back into the heat bath. We present a simple experimental procedure to test the assertion that adiabatic centrifugal compression is isothermal. An energy budget for the cycle provides a criterion for breakeven in the conversion of heat to mechanical energy.

Steam conversion of liquefied petroleum gas and methane in microchannel reactor

NASA Astrophysics Data System (ADS)

Dimov, S. V.; Gasenko, O. A.; Fokin, M. I.; Kuznetsov, V. V.

2018-03-01

This study presents experimental results of steam conversion of liquefied petroleum gas and methane in annular catalytic reactor - heat exchanger. The steam reforming was done on the Rh/Al2O3 nanocatalyst with the heat applied through the microchannel gap from the outer wall. Concentrations of the products of chemical reactions in the outlet gas mixture are measured at different temperatures of reactor. The range of channel wall temperatures at which the ratio of hydrogen and carbon oxide in the outlet mixture grows substantially is determined. Data on the composition of liquefied petroleum gas conversion products for the ratio S/C = 5 was received for different GHVS.

An alternative synthetic approach for efficient catalytic conversion of syngas to ethanol.

PubMed

Yue, Hairong; Ma, Xinbin; Gong, Jinlong

2014-05-20

Ethanol is an attractive end product and a versatile feedstock because a widespread market exists for its commercial use as a fuel additive or a potential substitute for gasoline. Currently, ethanol is produced primarily by fermentation of biomass-derived sugars, particularly those containing six carbons, but coproducts 5-carbon sugars and lignin remain unusable. Another major process for commercial production of ethanol is hydration of ethylene over solid acidic catalysts, yet not sustainable considering the depletion of fossil fuels. Catalytic conversion of synthetic gas (CO + H2) could produce ethanol in large quantities. However, the direct catalytic conversion of synthetic gas to ethanol remains challenging, and no commercial process exists as of today although the research has been ongoing for the past 90 years, since such the process suffers from low yield and poor selectivity due to slow kinetics of the initial C-C bond formation and fast chain growth of the C2 intermediates. This Account describes recent developments in an alternative approach for the synthesis of ethanol via synthetic gas. This process is an integrated technology consisting of the coupling of CO with methanol to form dimethyl oxalate and the subsequent hydrogenation to yield ethanol. The byproduct of the second step (methanol) can be separated and used in circulation as the feedstock for the coupling step. The coupling reaction of carbon monoxide for producing dimethyl oxalate takes place under moderate reaction conditions with high selectivity (∼95%), which ideally leads to a self-closing, nonwaste, catalytic cycling process. This Account also summarizes the progress on the development of copper-based catalysts for the hydrogenation reaction with remarkable efficiencies and stability. The unique lamellar structure and the cooperative effect between surface Cu(0) and Cu(+) species are responsible for the activity of the catalyst with high yield of ethanol (∼91%). The understanding of nature of valence states of Cu could also guide the rational design of Cu-based catalysts for other similar reactions, particularly for hydrogenation catalytic systems. In addition, by regulating the reaction condition and the surface structure of the catalysts, the products in the hydrogenation steps, such as ethanol, methyl glycolate, and ethylene glycol, could be tuned efficiently. This synthetic approach enables a more sustainable ethanol, methyl glycolate, and ethylene glycol synthesis in industry and greatly reduces the dependence on petroleum resources and the emission of the greenhouse gas.

Energy conversion in natural and artificial photosynthesis.

PubMed

McConnell, Iain; Li, Gonghu; Brudvig, Gary W

2010-05-28

Modern civilization is dependent upon fossil fuels, a nonrenewable energy source originally provided by the storage of solar energy. Fossil-fuel dependence has severe consequences, including energy security issues and greenhouse gas emissions. The consequences of fossil-fuel dependence could be avoided by fuel-producing artificial systems that mimic natural photosynthesis, directly converting solar energy to fuel. This review describes the three key components of solar energy conversion in photosynthesis: light harvesting, charge separation, and catalysis. These processes are compared in natural and in artificial systems. Such a comparison can assist in understanding the general principles of photosynthesis and in developing working devices, including photoelectrochemical cells, for solar energy conversion. 2010 Elsevier Ltd. All rights reserved.

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.

SOURCE APPORTIONMENT OF PRIMARY CARBONACEOUS AEROSOL USING THE COMMUNITY MULTISCALE AIR QUALITY MODEL

EPA Science Inventory

A substantial fraction of fine particulate matter (PM) across the United States is composed of carbon, which may be either emitted in particulate form (i.e., primary) or formed in the atmosphere through gas-to-particle conversion processes (i.e., secondary). Primary carbonaceous...

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.

Enhanced catalyst and process for converting synthesis gas to liquid motor fuels

DOEpatents

Coughlin, Peter K.

1986-01-01

The conversion of synthesis gas to liquid molar fuels by means of a cobalt Fischer-Tropsch catalyst composition is enhanced by the addition of molybdenum, tungsten or a combination thereof as an additional component of said composition. The presence of the additive component increases the olefinic content of the hydrocarbon products produced. The catalyst composition can advantageously include a support component, such as a molecular sieve, co-catalyst/support component or a combination of such support components.

43 CFR 3140.2-3 - Application requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Conversion of Existing Oil and Gas Leases and Valid Claims Based on Mineral Locations § 3140.2-3 Application... existing oil and gas lease or valid claim or for an area of proposed unit operation. (d) The plan of operations shall identify by lease number all Federal oil and gas leases proposed for conversion and identify...

43 CFR 3140.2-3 - Application requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Conversion of Existing Oil and Gas Leases and Valid Claims Based on Mineral Locations § 3140.2-3 Application... existing oil and gas lease or valid claim or for an area of proposed unit operation. (d) The plan of operations shall identify by lease number all Federal oil and gas leases proposed for conversion and identify...

43 CFR 3140.2-3 - Application requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Conversion of Existing Oil and Gas Leases and Valid Claims Based on Mineral Locations § 3140.2-3 Application... existing oil and gas lease or valid claim or for an area of proposed unit operation. (d) The plan of operations shall identify by lease number all Federal oil and gas leases proposed for conversion and identify...

43 CFR 3140.2-3 - Application requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Conversion of Existing Oil and Gas Leases and Valid Claims Based on Mineral Locations § 3140.2-3 Application... existing oil and gas lease or valid claim or for an area of proposed unit operation. (d) The plan of operations shall identify by lease number all Federal oil and gas leases proposed for conversion and identify...

Sorghums for methane production. Final report, April 1983 to March 1986

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

Hiler, E.A.; Miller, F.R.; Dominy, R.E.

1986-06-01

The objective of the research is to develop an integrated system for methane production utilizing high-energy sorghum as the feedstock. The report provides specifics of research activities in the sorghums-for-methane production program sponsored by Gas Research Institute and co-funded by Texas Agricultural Experiment Station. Emphasis is placed on third-year results in the report since first- and second-year results are given in earlier reports. Researchers in the program include plant geneticists, sorghum physiologists, chemists, agronomists, ruminant physiologists, agricultural and systems engineers, and agricultural economists. Major research emphasis is on genetic manipulation, physiology and production systems, harvesting, storage, processing and conversion systems,more » inhibitors, and economic and systems analyses. During the third year, increasing emphasis continued on the storage, processing, and conversion aspects of the program because of the critical importance of high efficiency and conversion to the economic implementation of the system.« less

Differentiation of South American crack and domestic (US) crack cocaine via headspace-gas chromatography/mass spectrometry.

PubMed

Colley, Valerie L; Casale, John F

2015-03-01

South American 'crack' cocaine, produced directly from coca leaf, can be distinguished from US domestically produced crack on the basis of occluded solvent profiles. In addition, analysis of domestically produced crack indicates the solvents that were used for cocaine hydrochloride (HCl) processing in South America. Samples of cocaine base (N=3) from South America and cocaine from the USA (N=157 base, N=88 HCl) were analyzed by headspace-gas chromatography-mass spectrometry (HS-GC-MS) to determine their solvent profiles. Each cocaine HCl sample was then converted to crack cocaine using the traditional crack production method and re-examined by HS-GC-MS. The resulting occluded solvent profiles were then compared to their original HCl solvent profiles. Analysis of the corresponding crack samples confirmed the same primary processing solvents found in the original HCl samples, but at reduced levels. Domestically seized crack samples also contained reduced levels of base-to-HCl conversion solvents. In contrast, analysis of South American crack samples confirmed the presence of low to high boiling hydrocarbons and no base-to-HCl conversion solvents. The presented study showed analysis of crack cocaine samples provides data on which processing solvents were originally utilized in the production of cocaine HCl in South America, prior to conversion to crack cocaine. Determination of processing solvents provides valuable information to the counter-drug intelligence community and assists the law enforcement community in determining cocaine distribution and trafficking routes throughout the world. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Converting to DEA/MDEA mix ups sweetening capacity

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

Spears, M.L.; Hagan, K.M.; Bullin, J.A.

1996-08-12

Mixing amines can be the best method for increasing capacity or improving efficiency in an amine sweetening unit. In many cases, it may be possible simply to add a second amine to the existing solution on the fly, or as the unit is running. Union Pacific Resources` Bryan, Tex., gas plant provides one example. The plant was converted from diethanolamine (DEA) to a DEA/MDEA (methyl DEA) mixture after analysis by TSWEET, a process-simulation program. After conversion, CO{sub 2} levels in the sales gas fell to less than pipeline specifications. Data were taken for the absorber at a constant amine circulationmore » of 120 gpm. A comparison of the performance data to the values calculated by the program proved the accuracy of TSWEET. The conversion and performance of the plant are described.« less

Development of Metal-impregnated Single Walled Carbon Nanotubes for Toxic Gas Contaminant Control in Advanced Life Support Systems

NASA Technical Reports Server (NTRS)

Pisharody, Suresh A.; Fisher, John W.; Wignarajah, K.

2002-01-01

The success of physico-chemical waste processing and resource recovery technologies for life support application depends partly on the ability of gas clean-up systems to efficiently remove trace contaminants generated during the process with minimal use of expendables. Carbon nanotubes promise superior performance over conventional approaches to gas clean-up due to their ability to direct the selective uptake of gaseous species based on their controlled pore size, high surface area, ordered chemical structure that allows functionalization and their effectiveness also as catalyst support materials for toxic gas conversion. We present results and findings from a preliminary study on the effectiveness of metal impregnated single walled nanotubes as catalyst/catalyst support materials for toxic gas contaminate control. The study included the purification of single walled nanotubes, the catalyst impregnation of the purified nanotubes, the experimental characterization of the surface properties of purified single walled nanotubes and the characterization of physisorption and chemisorption of uptake molecules.

Alkali Potassium Induced HCl/CO2 Selectivity Enhancement and Chlorination Reaction Inhibition for Catalytic Oxidation of Chloroaromatics.

PubMed

Sun, Pengfei; Wang, Wanglong; Weng, Xiaole; Dai, Xiaoxia; Wu, Zhongbiao

2018-06-05

Industrial combustion of chloroaromatics is likely to generate unintentional biphenyls (PCBs), polychlorinated dibenzo- p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). This process involves a surface-mediated reaction and can be accelerated in the presence of a catalyst. In the past decade, the effect of surface nature of applied catalysts on the conversion of chloroaromatics to PCBs/PCDD/PCDF has been well explored. However, studies on how the flue gas interferent components affect such a conversion process remain insufficient. In this article, a critical flue gas interferent component, alkali potassium, was investigated to reveal its effect on the chloroaromatics oxidation at a typical solid acid-base catalyst, Mn x Ce 1- x O 2 /HZSM-5. The loading of alkali potassium was found to improve the Lewis acidity of the catalyst (by increasing the amounts of surface Mn 4+ after calcination), which thus promoted the CO 2 selectivity for catalytic chlorobenzene (CB) oxidation. The KOH with a high hydrophilicity has favored the adsorption/activation of H 2 O molecules that provided sufficient hydroxyl groups and possibly induced a hydrolysis process to promote the formation of HCl. The K ion also served as a potential sink for chorine ions immobilization (via forming KCl). Both of these inhibited the formation of phenyl polychloride byproducts, thereby blocking the conversion of CB to chlorophenol and then PCDDs/PCDFs, and potentially ensuring a durable operation and less secondary pollution for the catalytic chloroaromatics combustion in industry.

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

Process simulation and comparison of biological conversion of syngas and hydrogen in biogas plants

NASA Astrophysics Data System (ADS)

Awais Salman, Chaudhary; Schwede, Sebastian; Thorin, Eva; Yan, Jinyue

2017-11-01

Organic waste is a good source of clean energy. However, different fractions of waste have to be utilized efficiently. One way is to find pathways to convert waste into useful products via various available processes (gasification, pyrolysis anaerobic digestion, etc.) and integrate them to increase the combined efficiency of the process. The syngas and hydrogen produced from the thermal conversion of biomass can be upgraded to biomethane via biological methanation. The current study presents the simulation model to predict the amount of biomethane produced by injecting the hydrogen and syngas. Hydrogen injection is modelled both in-situ and ex-situ while for syngas solely the ex-situ case has been studied. The results showed that 85% of the hydrogen conversion was achieved for the ex-situ reactor while 81% conversion rate was achieved for the in-situ reactor. The syngas could be converted completely in the bio-reactor. However, the addition of syngas resulted in an increase of carbon dioxide. Simulation of biomethanation of gas addition showed a biomethane concentration of 87% while for hydrogen addition an increase of 74% and 80% for in-situ and ex-situ addition respectively.

Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 1: Introduction and summary and general assumptions. [energy conversion systems for electric power plants using coal - feasibility

NASA Technical Reports Server (NTRS)

Beecher, D. T.

1976-01-01

Nine advanced energy conversion concepts using coal or coal-derived fuels are summarized. They are; (1) open-cycle gas turbines, (2) combined gas-steam turbine cycles, (3) closed-cycle gas turbines, (4) metal vapor Rankine topping, (5) open-cycle MHD; (6) closed-cycle MHD; (7) liquid-metal MHD; (8) advanced steam; and (9) fuel cell systems. The economics, natural resource requirements, and performance criteria for the nine concepts are discussed.

Fleet Conversion in Local Government: Determinants of Driver Fuel Choice for Bi-Fuel Vehicles

ERIC Educational Resources Information Center

Johns, Kimberly D.; Khovanova, Kseniya M.; Welch, Eric W.

2009-01-01

This study evaluates the conversion of one local government's fleet from gasoline to bi-fuel E-85, compressed natural gas, and liquid propane gas powered vehicles at the midpoint of a 10-year conversion plan. This study employs a behavioral model based on the theory of reasoned action to explore factors that influence an individual's perceived and…

The O₂-enriched air gasification of coal, plastics and wood in a fluidized bed reactor.

PubMed

Mastellone, Maria Laura; Zaccariello, Lucio; Santoro, Donato; Arena, Umberto

2012-04-01

The effect of oxygen-enriched air during fluidized bed co-gasification of a mixture of coal, plastics and wood has been investigated. The main components of the obtained syngas were measured by means of on-line analyzers and a gas chromatograph while those of the condensate phase were off-line analysed by means of a gas chromatography-mass spectrometer (GC-MS). The characterization of condensate phase as well as that of the water used as scrubbing medium completed the performed diagnostics. The experimental results were further elaborated in order to provide material and substances flow analyses inside the plant boundaries. These analyses allowed to obtain the main substance distribution between solid, gaseous and condensate phases and to estimate the conversion efficiency of carbon and hydrogen but also to easily visualise the waste streams produced by the process. The process performance was then evaluated on the basis of parameters related to the conversion efficiency of fuels into valuable products (i.e. by considering tar and particulate as process losses) as well as those related to the energy recovery. Copyright © 2011 Elsevier Ltd. All rights reserved.

Serious simulation game development for energy transition education using integrated framework game design

NASA Astrophysics Data System (ADS)

Destyanto, A. R.; Putri, O. A.; Hidayatno, A.

2017-11-01

Due to the advantages that serious simulation game offered, many areas of studies, including energy, have used serious simulation games as their instruments. However, serious simulation games in the field of energy transition still have few attentions. In this study, serious simulation game is developed and tested as the activity of public education about energy transition which is a conversion from oil to natural gas program. The aim of the game development is to create understanding and awareness about the importance of energy transition for society in accelerating the process of energy transition in Indonesia since 1987 the energy transition program has not achieved the conversion target yet due to the lack of education about energy transition for society. Developed as a digital serious simulation game following the framework of integrated game design, the Transergy game has been tested to 15 users and then analysed. The result of verification and validation of the game shows that Transergy gives significance to the users for understanding and triggering the needs of oil to natural gas conversion.

Catalysts and process for liquid hydrocarbon fuel production

DOEpatents

White, Mark G.; Ranaweera, Samantha A.; Henry, William P.

2016-08-02

The present invention provides a novel process and system in which a mixture of carbon monoxide and hydrogen synthesis gas, or syngas, is converted into hydrocarbon mixtures composed of high quality distillates, gasoline components, and lower molecular weight gaseous olefins in one reactor or step. The invention utilizes a novel supported bimetallic ion complex catalyst for conversion, and provides methods of preparing such novel catalysts and use of the novel catalysts in the process and system of the invention.

Energy recovery from waste glycerol by utilizing thermal water vapor plasma.

PubMed

Tamošiūnas, Andrius; Valatkevičius, Pranas; Gimžauskaitė, Dovilė; Jeguirim, Mejdi; Mėčius, Vladas; Aikas, Mindaugas

2017-04-01

Glycerol, considered as a waste feedstock resulting from biodiesel production, has received much attention in recent years due to its properties, which offer to recover energy. The aim of this study was to investigate the use of a thermal water vapor plasma for waste (crude) glycerol conversion to synthesis gas, or syngas (H 2  + CO). In parallel of crude glycerol, a pure glycerol (99.5%) was used as a reference material in order to compare the concentrations of the formed product gas. A direct current (DC) arc plasma torch stabilized by a mixture of argon/water vapor was utilized for the effective glycerol conversion to hydrogen-rich synthesis gas. It was found that after waste glycerol treatment, the main reaction products were gases with corresponding concentrations of H 2 50.7%, CO 23.53%, CO 2 11.45%, and CH 4 3.82%, and traces of C 2 H 2 and C 2 H 6 , which concentrations were below 0.5%. The comparable concentrations of the formed gas products were obtained after pure glycerol conversion-H 2 46.4%, CO 26.25%, CO 2 11.3%, and CH 4 4.7%. The use of thermal water vapor plasma producing synthesis gas is an effective method to recover energy from both crude and pure glycerol. The performance of the glycerol conversion system was defined in terms of the produced gas yield, the carbon conversion efficiency, the cold gas efficiency, and the specific energy requirements.

Production of synthetic fuels using syngas from a steam hydrogasification and reforming process

NASA Astrophysics Data System (ADS)

Raju, Arun Satheesh Kumar

This thesis is aimed at the research, optimization and development of a thermo-chemical process aimed at the production of synthesis gas (mixture of H2 and CO) with a flexible H2 to CO ratio using coupled steam hydrogasification and steam reforming processes. The steam hydrogasification step generates a product gas containing significant amounts of methane by gasifying a carbonaceous feed material with steam and internally generated H2. This product gas is converted to synthesis gas with an excess H2 to CO using the steam reformer. Research involving experimental and simulation work has been conducted on steam hydrogasification, steam reforming and the Fischer-Tropsch reaction. The Aspen Plus simulation tool has been used to develop a process model that can perform heat and mass balance calculations of the whole process using built-in reactor modules and an empirical FT model available in the literature. This model has been used to estimate optimum feed ratios and process conditions for specific feedstocks and products. Steam hydrogasification of coal and wood mixtures of varying coal to wood ratios has been performed in a stirred batch reactor. The carbon conversion of the feedstocks to gaseous products is around 60% at 700°C and 80% at 800°C. The coal to wood ratio of the feedstock does not exert a significant influence on the carbon conversion. The rates of formation of CO, CO 2 and CH4 during gasification have been calculated based on the experimental results using a simple kinetic model. Experimental research on steam reforming has been performed. It has been shown that temperature and the feed CO2/CH4 ratio play a dominant role in determining the product gas H2/CO ratio. Reforming of typical steam hydrogasification product-gas stream has been investigated over a commercial steam reforming catalyst. The results demonstrate that the combined use of steam hydrogasification process with a reformer can generate a synthesis gas with a predetermined H2/CO ratio from carbonaceous feedstocks. Experimental work on the Fischer-Tropsch synthesis has also been performed. A life cycle analysis has been performed with the objective of comparing the life cycle energy consumption and emissions of synthetic diesel fuel produced through the CE-CERT process with other fuel/vehicle combinations. The experimental and simulation results presented here demonstrate that the CE-CERT process is versatile and can potentially handle a number of different feedstocks. CE-CERT process appears to be suitable for commercialization in very large scales with a coal feedstock and also in a distributed network of smaller scale reactors utilizing localized renewable feedstocks.

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

Cogeneration technology alternatives study. Volume 1: Summary report

NASA Technical Reports Server (NTRS)

1980-01-01

Data and information in the area of advanced energy conversion systems for industrial congeneration applications in the 1985-2000 time period was studied. Six current and thirty-one advanced energy conversion systems were defined and combined with appropriate balance-of-plant equipment. Twenty-six industrial processes were selected from among the high energy consuming industries to serve as a framework for the study. Each conversion system was analyzed as a cogenerator with each industrial plant. Fuel consumption, costs, and environmental intrusion were evaluated and compared to corresponding traditional values. Various cogeneration strategies were analyzed and both topping and bottoming (using industrial by-product heat) applications were included. The advanced energy conversion technologies indicated reduced fuel consumption, costs, and emissions. Typically fuel energy savings of 10 to 25 percent were predicted compared to traditional on-site furnaces and utility electricity. With the variety of industrial requirements, each advanced technology had attractive applications. Overall, fuel cells indicated the greatest fuel energy savings and emission reductions. Gas turbines and combined cycles indicated high overall annual cost savings. Steam turbines and gas turbines produced high estimated returns. In some applications, diesels were most efficient. The advanced technologies used coal-derived fuels, or coal with advanced fluid bed combustion or on-site gasification systems.

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.

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

Integrated bioprocess for conversion of gaseous substrates to liquids

PubMed Central

Hu, Peng; Chakraborty, Sagar; Kumar, Amit; Woolston, Benjamin; Liu, Hongjuan; Emerson, David; Stephanopoulos, Gregory

2016-01-01

In the quest for inexpensive feedstocks for the cost-effective production of liquid fuels, we have examined gaseous substrates that could be made available at low cost and sufficiently large scale for industrial fuel production. Here we introduce a new bioconversion scheme that effectively converts syngas, generated from gasification of coal, natural gas, or biomass, into lipids that can be used for biodiesel production. We present an integrated conversion method comprising a two-stage system. In the first stage, an anaerobic bioreactor converts mixtures of gases of CO2 and CO or H2 to acetic acid, using the anaerobic acetogen Moorella thermoacetica. The acetic acid product is fed as a substrate to a second bioreactor, where it is converted aerobically into lipids by an engineered oleaginous yeast, Yarrowia lipolytica. We first describe the process carried out in each reactor and then present an integrated system that produces microbial oil, using synthesis gas as input. The integrated continuous bench-scale reactor system produced 18 g/L of C16-C18 triacylglycerides directly from synthesis gas, with an overall productivity of 0.19 g⋅L−1⋅h−1 and a lipid content of 36%. Although suboptimal relative to the performance of the individual reactor components, the presented integrated system demonstrates the feasibility of substantial net fixation of carbon dioxide and conversion of gaseous feedstocks to lipids for biodiesel production. The system can be further optimized to approach the performance of its individual units so that it can be used for the economical conversion of waste gases from steel mills to valuable liquid fuels for transportation. PMID:26951649

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.

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.

A QUANTITATIVE STUDY OF THE EVOLUTION OF GASES FROM ELECTRON TUBES AND MATERIALS.

DTIC Science & Technology

spectrometer, ion pumps, ionization gauges and precision orifices to measure the flow rate of individual gases. It has been used to examine several...amounts comprise about 95% of the gas evolved during cathode conversion and activation. Additional experiments in the dynamic analysis of tube processes are suggested. (Author)

THE EFFECTS OF PARTIAL CONDENSATION AROUND IONS IN ELECTRIC FLUID DYNAMIC ENERGY CONVERSION PROCESSES.

DTIC Science & Technology

theoretically. Negative ions are produced by a corona discharge from a needle placed along the axis of a nozzle. A dense air-vapor mixture is...interaction with the gas molecules to an electrode of high potential. The effectiveness of the viscous coupling depends on the charge mobility being

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.

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.

A high temperature drop-tube and packed-bed solar reactor for continuous biomass gasification

NASA Astrophysics Data System (ADS)

Bellouard, Quentin; Abanades, Stéphane; Rodat, Sylvain; Dupassieux, Nathalie

2017-06-01

Biomass gasification is an attractive process to produce high-value syngas. Utilization of concentrated solar energy as the heat source for driving reactions increases the energy conversion efficiency, saves biomass resource, and eliminates the needs for gas cleaning and separation. A high-temperature tubular solar reactor combining drop tube and packed bed concepts was used for continuous solar-driven gasification of biomass. This 1 kW reactor was experimentally tested with biomass feeding under real solar irradiation conditions at the focus of a 2 m-diameter parabolic solar concentrator. Experiments were conducted at temperatures ranging from 1000°C to 1400°C using wood composed of a mix of pine and spruce (bark included) as biomass feedstock. The aim of this study was to demonstrate the feasibility of syngas production in this reactor concept and to prove the reliability of continuous biomass gasification processing using solar energy. The study first consisted of a parametric study of the gasification conditions to obtain an optimal gas yield. The influence of temperature and oxidizing agent (H2O or CO2) on the product gas composition was investigated. The study then focused on solar gasification during continuous biomass particle injection for demonstrating the feasibility of a continuous process. Regarding the energy conversion efficiency of the lab scale reactor, energy upgrade factor of 1.21 and solar-to-fuel thermochemical efficiency up to 28% were achieved using wood heated up to 1400°C.

On-line carbon balance of yeast fermentations using miniaturized optical sensors.

PubMed

Beuermann, Thomas; Egly, Dominik; Geoerg, Daniel; Klug, Kerris Isolde; Storhas, Winfried; Methner, Frank-Juergen

2012-03-01

Monitoring of microbiological processes using optical sensors and spectrometers has gained in importance over the past few years due to its advantage in enabling non-invasive on-line analysis. Near-infrared (NIR) and mid-infrared (MIR) spectrometer set-ups in combination with multivariate calibrations have already been successfully employed for the simultaneous determination of different metabolites in microbiological processes. Photometric sensors, in addition to their low price compared to spectrometer set-ups, have the advantage of being compact and are easy to calibrate and operate. In this work, the detection of ethanol and CO(2) in the exhaust gas during aerobic yeast fermentation was performed by two photometric gas analyzers, and dry yeast biomass was monitored using a fiber optic backscatter set-up. The optical sensors could be easily fitted to the bioreactor and exhibited high robustness during measuring. The ethanol content of the fermentation broth was monitored on-line by measuring the ethanol concentration in the fermentation exhaust and applying a conversion factor. The vapor/liquid equilibrium and the associated conversion factor strongly depend on the process parameter temperature but not on aeration and stirring rate. Dry yeast biomass was determined in-line by a backscattering signal applying a linear calibration. An on-line balance with a recovery rate of 95-97% for carbon was achieved with the use of three optical sensors (two infrared gas analyzers and one fiber optic backscatter set-up). Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

A novel integrated biorefinery process for diesel fuel blendstock production using lipids from the methanotroph, Methylomicrobium buryatense

DOE PAGES

Dong, Tao; Fei, Qiang; Genelot, Marie; ...

2017-03-08

In light of the availability of low-cost methane (CH 4) derived from natural gas and biogas along with increasing concerns of the greenhouse gas emissions, the production of alternative liquid biofuels directly from CH 4 is a promising approach to capturing wasted energy. A novel biorefinery concept integrating biological conversion of CH 4 to microbial lipids together with lipid extraction and generation of hydrocarbon fuels is demonstrated in this study for the first time. An aerobic methanotrophic bacterium, Methylomicrobium buryatense capable of using CH 4 as the sole carbon source was selected on the basis of genetic tractability, cultivation robustness,more » and ability to accumulate phospholipids in membranes. A maximum fatty acid content of 10% of dry cell weight was obtained in batch cultures grown in a continuous gas sparging fermentation system. Although phospholipids are not typically considered as a good feedstock for upgrading to hydrocarbon fuels, we set out to demonstrate that using a combination of novel lipid extraction methodology with advanced catalyst design, we could prove the feasibility of this approach. Up to 95% of the total fatty acids from membrane-bound phospholipids were recovered by a two-stage pretreatment method followed by hexane extraction of the aqueous hydrolysate. The upgrading of extracted lipids was then demonstrated in a hydrodeoxygeation process using palladium on silica as a catalyst. Lipid conversion in excess of 99% was achieved, with a full selectivity to hydrocarbons. Lastly, the final hydrocarbon mixture is dominated by 88% pentadecane (C 15H 32) based on decarbonylation/decarboxylation and hydrogenation of C16 fatty acids, indicating that a biological gas-to-liquid fuel (Bio-GTL) process is technically feasible.« less

Low cost solar array project 1: Silicon material

NASA Technical Reports Server (NTRS)

Jewett, D. N.; Bates, H. E.; Hill, D. M.

1980-01-01

The low cost production of silicon by deposition of silicon from a hydrogen/chlorosilane mixture is described. Reactor design, reaction vessel support systems (physical support, power control and heaters, and temperature monitoring systems) and operation of the system are reviewed. Testing of four silicon deposition reactors is described, and test data and consequently derived data are given. An 18% conversion of trichlorosilane to silicon was achieved, but average conversion rates were lower than predicted due to incomplete removal of byproduct gases for recycling and silicon oxide/silicon polymer plugging of the gas outlet. Increasing the number of baffles inside the reaction vessel improved the conversion rate. Plans for further design and process improvements to correct the problems encountered are outlined.

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

Detering, B.A.; Kong, P.C.; Thomas, C.P.

This paper describes the experimental demonstration of a process for direct conversion of methane to acetylene in a thermal plasma. The process utilizes a thermal plasma to dissociate methane and form an equilibrium mixture of acetylene followed by a supersonic expansion of the hot gas to preserve the produced acetylene in high yield. The high translational velocities and rapid cooling result in an overpopulation of atomic hydrogen which persists throughout the expansion process. The presence of atomic hydrogen shifts the equilibrium composition by inhibiting complete pyrolysis of methane and acetylene to solid carbon. This process has the potential to reducemore » the cost of producing acetylene from natural gas. Acetylene and hydrogen produced by this process could be used directly as industrial gases, building blocks for synthesis of industrial chemicals, or oligomerized to long chain liquid hydrocarbons for use as fuels. This process produces hydrogen and ultrafine carbon black in addition to acetylene.« less

Promoted Iron Nanocrystals Obtained via Ligand Exchange as Active and Selective Catalysts for Synthesis Gas Conversion

PubMed Central

2017-01-01

Colloidal synthesis routes have been recently used to fabricate heterogeneous catalysts with more controllable and homogeneous properties. Herein a method was developed to modify the surface composition of colloidal nanocrystal catalysts and to purposely introduce specific atoms via ligands and change the catalyst reactivity. Organic ligands adsorbed on the surface of iron oxide catalysts were exchanged with inorganic species such as Na2S, not only to provide an active surface but also to introduce controlled amounts of Na and S acting as promoters for the catalytic process. The catalyst composition was optimized for the Fischer–Tropsch direct conversion of synthesis gas into lower olefins. At industrially relevant conditions, these nanocrystal-based catalysts with controlled composition were more active, selective, and stable than catalysts with similar composition but synthesized using conventional methods, possibly due to their homogeneity of properties and synergic interaction of iron and promoters. PMID:28824820

Printable enzyme-embedded materials for methane to methanol conversion

DOE PAGES

Blanchette, Craig D.; Knipe, Jennifer M.; Stolaroff, Joshuah K.; ...

2016-06-15

An industrial process for the selective activation of methane under mild conditions would be highly valuable for controlling emissions to the environment and for utilizing vast new sources of natural gas. The only selective catalysts for methane activation and conversion to methanol under mild conditions are methane monooxygenases (MMOs) found in methanotrophic bacteria; however, these enzymes are not amenable to standard enzyme immobilization approaches. Using particulate methane monooxygenase (pMMO), we create a biocatalytic polymer material that converts methane to methanol. We demonstrate embedding the material within a silicone lattice to create mechanically robust, gas-permeable membranes, and direct printing of micron-scalemore » structures with controlled geometry. Remarkably, the enzymes retain up to 100% activity in the polymer construct. The printed enzyme-embedded polymer motif is highly flexible for future development and should be useful in a wide range of applications, especially those involving gas–liquid reactions.« less

Printable enzyme-embedded materials for methane to methanol conversion

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

Blanchette, Craig D.; Knipe, Jennifer M.; Stolaroff, Joshuah K.

An industrial process for the selective activation of methane under mild conditions would be highly valuable for controlling emissions to the environment and for utilizing vast new sources of natural gas. The only selective catalysts for methane activation and conversion to methanol under mild conditions are methane monooxygenases (MMOs) found in methanotrophic bacteria; however, these enzymes are not amenable to standard enzyme immobilization approaches. Using particulate methane monooxygenase (pMMO), we create a biocatalytic polymer material that converts methane to methanol. We demonstrate embedding the material within a silicone lattice to create mechanically robust, gas-permeable membranes, and direct printing of micron-scalemore » structures with controlled geometry. Remarkably, the enzymes retain up to 100% activity in the polymer construct. The printed enzyme-embedded polymer motif is highly flexible for future development and should be useful in a wide range of applications, especially those involving gas–liquid reactions.« less

Printable enzyme-embedded materials for methane to methanol conversion

PubMed Central

Blanchette, Craig D.; Knipe, Jennifer M.; Stolaroff, Joshuah K.; DeOtte, Joshua R.; Oakdale, James S.; Maiti, Amitesh; Lenhardt, Jeremy M.; Sirajuddin, Sarah; Rosenzweig, Amy C.; Baker, Sarah E.

2016-01-01

An industrial process for the selective activation of methane under mild conditions would be highly valuable for controlling emissions to the environment and for utilizing vast new sources of natural gas. The only selective catalysts for methane activation and conversion to methanol under mild conditions are methane monooxygenases (MMOs) found in methanotrophic bacteria; however, these enzymes are not amenable to standard enzyme immobilization approaches. Using particulate methane monooxygenase (pMMO), we create a biocatalytic polymer material that converts methane to methanol. We demonstrate embedding the material within a silicone lattice to create mechanically robust, gas-permeable membranes, and direct printing of micron-scale structures with controlled geometry. Remarkably, the enzymes retain up to 100% activity in the polymer construct. The printed enzyme-embedded polymer motif is highly flexible for future development and should be useful in a wide range of applications, especially those involving gas–liquid reactions. PMID:27301270

Metallurgical technologies, energy conversion, and magnetohydrodynamic flows

NASA Astrophysics Data System (ADS)

Branover, Herman; Unger, Yeshajahu

The present volume discusses metallurgical applications of MHD, R&D on MHD devices employing liquid working medium for process applications, electromagnetic (EM) modulation of molten metal flow, EM pump performance of superconducting MHD devices, induction EM alkali-metal pumps, a physical model for EM-driven flow in channel-induction furnaces, grain refinement in Al alloys via EM vibrational method, dendrite growth of solidifying metal in dc magnetic field, MHD for mass and heat transfer in single-crystal melt growth, inverse EM shaping, and liquid-metal MHD development in Israel. Also discussed are the embrittlement of steel by lead, an open cycle MHD disk generator, the acceleration of gas-liquid piston flows for molten-metal MHD generators, MHD flow around a cylinder, new MHD drag coefficients, liquid-metal MHD two-phase flow, and two-phase liquid gas mixers for MHD energy conversion. (No individual items are abstracted in this volume)

Alternative process schemes for coal conversion. Progress report No. 1, October 1, 1978--January 31, 1979

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

Sansone, M.J.

1979-02-01

On the basis of simple, first approximation calculations, it has been shown that catalytic gasification and hydrogasification are inherently superior to conventional gasification with respect to carbon utilization and thermal efficiency. However, most processes which are directed toward the production of substitute natural gas (SNG) by direct combination of coal with steam at low temperatures (catalytic processes) or with hydrogen (hydrogasification) will require a step for separation of product SNG from a recycle stream. The success or falure of the process could well depend upon the economics of this separation scheme. The energetics for the separation of mixtures of idealmore » gases has been considered in some detail. Minimum energies for complete separation of representative effluent mixtures have been calculated as well as energies for separation into product and recycle streams. The gas mixtures include binary systems of H/sub 2/ and CH/sub 4/ and ternary mixtures of H/sub 2/, CH/sub 4/, and CO. A brief summary of a number of different real separation schemes has also been included. We have arbitrarily divided these into five categories: liquefaction, absorption, adsorption, chemical, and diffusional methods. These separation methods will be screened and the more promising methods examined in more detail in later reports. Finally, a brief mention of alternative coal conversion processes concludes this report.« less

Surface acoustic wave sensors/gas chromatography; and Low quality natural gas sulfur removal and recovery CNG Claus sulfur recovery process

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

Klint, B.W.; Dale, P.R.; Stephenson, C.

This topical report consists of the two titled projects. Surface Acoustic Wave/Gas Chromatography (SAW/GC) provides a cost-effective system for collecting real-time field screening data for characterization of vapor streams contaminated with volatile organic compounds (VOCs). The Model 4100 can be used in a field screening mode to produce chromatograms in 10 seconds. This capability will allow a project manager to make immediate decisions and to avoid the long delays and high costs associated with analysis by off-site analytical laboratories. The Model 4100 is currently under evaluation by the California Environmental Protection Agency Technology Certification Program. Initial certification focuses upon themore » following organics: cis-dichloroethylene, chloroform, carbon tetrachloride, trichlorethylene, tetrachloroethylene, tetrachloroethane, benzene, ethylbenzene, toluene, and o-xylene. In the second study the CNG Claus process is being evaluated for conversion and recovery of elemental sulfur from hydrogen sulfide, especially found in low quality natural gas. This report describes the design, construction and operation of a pilot scale plant built to demonstrate the technical feasibility of the integrated CNG Claus process.« less

Conversion of ammonia into hydrogen and nitrogen by reaction with a sulfided catalyst

DOEpatents

Matthews, Charles W.

1977-01-01

A method is provided for removing ammonia from the sour water stream of a coal gasification process. The basic steps comprise stripping the ammonia from the sour water; heating the stripped ammonia to a temperature from between 400.degree. to 1,000.degree. F; passing the gaseous ammonia through a reactor containing a sulfided catalyst to produce elemental hydrogen and nitrogen; and scrubbing the reaction product to obtain an ammonia-free gas. The residual equilibrium ammonia produced by the reactor is recycled into the stripper. The ammonia-free gas may be advantageously treated in a Claus process to recover elemental sulfur. Iron sulfide or cobalt molybdenum sulfide catalysts are used.

Technique for measuring gas conversion factors

NASA Technical Reports Server (NTRS)

Singh, J. J.; Sprinkle, D. R. (Inventor)

1985-01-01

A method for determining hydrocarbon conversion factors for a flowmeter. A mixture of air, O2 and C sub x H sub y is burned and the partial paressure of O2 in the resulting gas is forced to equal the partial pressure of O2 in air. The flowrate of O2 flowing into the mixture is measured by flowmeter and the flowrate of C sub x H sub y flowing into the mixture is measured by the flowmeter conversion factor is to be determined. These measured values are used to calculate the conversion factor.

CO2 injection into submarine, CH4-hydrate bearing sediments: Parameter studies towards the development of a hydrate conversion technology

NASA Astrophysics Data System (ADS)

Deusner, Christian; Bigalke, Nikolaus; Kossel, Elke; Haeckel, Matthias

2013-04-01

In the recent past, international research efforts towards exploitation of submarine and permafrost hydrate reservoirs have increased substantially. Until now, findings indicate that a combination of different technical means such as depressurization, thermal stimulation and chemical activation is the most promising approach for producing gas from natural hydrates. Moreover, emission neutral exploitation of CH4-hydrates could potentially be achieved in a combined process with CO2 injection and storage as CO2-hydrate. In the German gas hydrate initiative SUGAR, a combination of experimental and numerical studies is used to elucidate the process mechanisms and technical parameters on different scales. Experiments were carried out in the novel high-pressure flow-through system NESSI (Natural Environment Simulator for sub-Seafloor Interactions). Recent findings suggest that the injection of heated, supercritical CO2 is beneficial for both CH4 production and CO2 retention. Among the parameters tested so far are the CO2 injection regime (alternating vs. continuous injection) and the reservoir pressure / temperature conditions. Currently, the influence of CO2 injection temperature is investigated. It was shown that CH4 production is optimal at intermediate reservoir temperatures (8 ° C) compared to lower (2 ° C) and higher temperatures (10 ° C). The reservoir pressure, however, was of minor importance for the production efficiency. At 8 ° C, where CH4- and CO2-hydrates are thermodynamically stable, CO2-hydrate formation appears to be slow. Eventual clogging of fluid conduits due to CO2-rich hydrate formation force open new conduits, thereby tapping different regions inside the CH4-hydrate sample volume for CH4gas. In contrast, at 2 ° C immediate formation of CO2-hydrate results in rapid and irreversible obstruction of the entire pore space. At 10 ° C pure CO2-hydrates can no longer be formed. Consequently the injected CO2 flows through quickly and interaction with the reservoir is minimized. Our results clearly indicate that the formation of mixed CH4-CO2-hydrates is an important aspect in the conversion process. The experimental studies have shown that the injection of heated CO2 into the hydrate reservoir induces a variety of spatial and temporal processes which result in substantial bulk heterogeneity. Current numerical simulators are not able to predict these process dynamics and it is important to improve available transport-reaction models (e.g. to include the effect of bulk sediment permeability on the conversion dynamics). Our results confirm that experimental studies are important to better understand the mechanisms of hydrate dissociation and conversion at CO2-injection conditions as a basis towards the development of a suitable hydrate conversion technology. The application of non-invasive analytical methods such as Magnetic Resonance Imaging (MRI) and Raman microscopy are important tools, which were applied to resolve process dynamics on the pore scale. Additionally, the NESSI system is being modified to allow high-pressure flow-through experiments under triaxial loading to better simulate hydrate-sediment mechanics. This aspect is important for overall process development and evaluation of process safety issues.

Vehicle conversion to hybrid gasoline/alternative fuel operation

NASA Technical Reports Server (NTRS)

Donakowski, T. D.

1982-01-01

The alternative fuels considered are compressed natural gas (CNG), liquefied natural gas (LNG), liquid petroleum gas (LPG), and methanol; vehicles were required to operate in a hybrid or dual-fuel gasoline/alternative fuel mode. Economic feasibility was determined by comparing the costs of continued use of gasoline fuel with the use of alternative fuel and retrofitted equipment. Differences in the amounts of future expenditures are adjusted by means of a total life-cycle costing. All fuels studied are technically feasible to allow a retrofit conversion to hybrid gasoline/alternative fuel operation except for methanol. Conversion to LPG is not recommended for vehicles with more than 100,000 km (60,000 miles) of prior use. Methanol conversion is not recommended for vehicles with more than 50,00 km (30,000 miles).

Conversion of NO to NO(2) in air by a micro electric NO(x) converter based on a corona discharge process.

PubMed

Yoon, Seung-Il; Heo, Sungmoo; Song, Soonho; Kim, Yong-Jun

2010-06-01

A micro-electric-NO(x)-converter based on volume treatment is proposed for the evaluation of NO(x) concentrations in air. It can electrically convert NO(x) mixture from variable mixing rates into a fixed-mixing rate of 25% NO(2) and 75% NO using the corona discharge process with stable conversion efficiency and high throughput (space velocity = 6.3 x 10(4) h(-1)). The micro-electric-NO(x)-converter is based on a volume process. Applying high voltage to the electrodes of the micro-electric-NO(x)-converter generates a corona discharge. This discharge creates high-energy electrons, which collide with gas molecules. After these collisions, NO and O(2) are broken into single atoms, and they are re-combined as a balanced form, NO(2) in this case. The fabricated micro-electric-NO(x)-converter converted NO into NO(2) at conversion efficiency of 25.63%, when 5.5 kV (the applied corona power = 0.196 W) was applied to the micro-electric-NO(x)-converter.

Feasibility of a peat biogasification process

NASA Astrophysics Data System (ADS)

Buivid, M. G.; Wise, D. L.; Rader, A. M.; McCarty, P. L.; Owen, W. F.

1980-07-01

The feasibility of a two-stage biogasification process for the conversion of peat reserves, the energy content of which in the United States is greater than that of uranium, shale oil or petroleum and natural gas combined, into pipeline-quality methane is investigated. Samples of wet-harvested reed-sedge peat were pretreated in alkaline and nonalkaline conditions in the presence and absence of oxidation in order to determine the most favorable conditions for the conversion of cellulosic and lignaceous fractions to water-soluble, fermentable compounds, and the resulting products were subjected to anaerobic fermentation to methane. Conversion efficiencies obtained reveal that up to 26% of the initial heat content of peat was converted to methane when alkaline heat pretreatment was employed. Analysis of the process parameters by a computer model to determine equipment sizes, mass and energy balances and costs indicates that for a 79,200 GJ/day plant the total capital requirement would be $323,000,000, annual operating costs would be $44,000,000 and average SNG cost would be $3.16/GJ, assuming a 90% stream factor with a delivered peat slurry costing $0.0033/kg.

Preliminary draft industrial siting administration permit application: Socioeconomic factors technical report. Final technical report, November 1980-May 1982. [Proposed WyCoalGas project in Converse County, Wyoming

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

Not Available

1982-01-01

Under the with-project scenario, WyCoalGas is projected to make a difference in the long-range future of Converse County. Because of the size of the proposed construction and operations work forces, the projected changes in employment, income, labor force, and population will alter Converse County's economic role in the region. Specifically, as growth occurs, Converse County will begin to satisfy a larger portion of its own higher-ordered demands, those that are currently being satisfied by the economy of Casper. Business-serving and household-serving activities, currently absent, will find the larger income and population base forecast to occur with the WyCoalGas project desirable.more » Converse County's economy will begin to mature, moving away from strict dependence on extractive industries to a more sophisticated structure that could eventually appeal to national, and certainly, regional markets. The technical demand of the WyCoalGas plant will mean a significant influx of varying occupations and skills. The creation of basic manufacturing, advanced trade and service sectors, and concomitant finance and transportation firms will make Converse County more economically autonomous. The county will also begin to serve market center functions for the smaller counties of eastern Wyoming that currently rely on Casper, Cheyenne or other distant market centers. The projected conditions expected to exist in the absence of the WyCoalGas project, the socioeconomic conditions that would accompany the project, and the differences between the two scenarios are considered. The analysis is keyed to the linkages between Converse County and Natrona County.« less

Wabash Valley Integrated Gasification Combined Cycle, Coal to Fischer Tropsch Jet Fuel Conversion Study

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

Shah, Jayesh; Hess, Fernando; Horzen, Wessel van

This reports examines the feasibility of converting the existing Wabash Integrated Gasification Combined Cycle (IGCC) plant into a liquid fuel facility, with the goal of maximizing jet fuel production. The fuels produced are required to be in compliance with Section 526 of the Energy Independence and Security Act of 2007 (EISA 2007 §526) lifecycle greenhouse gas (GHG) emissions requirements, so lifecycle GHG emissions from the fuel must be equal to or better than conventional fuels. Retrofitting an existing gasification facility reduces the technical risk and capital costs associated with a coal to liquids project, leading to a higher probability ofmore » implementation and more competitive liquid fuel prices. The existing combustion turbine will continue to operate on low cost natural gas and low carbon fuel gas from the gasification facility. The gasification technology utilized at Wabash is the E-Gas™ Technology and has been in commercial operation since 1995. In order to minimize capital costs, the study maximizes reuse of existing equipment with minimal modifications. Plant data and process models were used to develop process data for downstream units. Process modeling was utilized for the syngas conditioning, acid gas removal, CO 2 compression and utility units. Syngas conversion to Fischer Tropsch (FT) liquids and upgrading of the liquids was modeled and designed by Johnson Matthey Davy Technologies (JM Davy). In order to maintain the GHG emission profile below that of conventional fuels, the CO 2 from the process must be captured and exported for sequestration or enhanced oil recovery. In addition the power utilized for the plant’s auxiliary loads had to be supplied by a low carbon fuel source. Since the process produces a fuel gas with sufficient energy content to power the plant’s loads, this fuel gas was converted to hydrogen and exported to the existing gas turbine for low carbon power production. Utilizing low carbon fuel gas and process steam in the existing combined cycle power plant provides sufficient power for all plant loads. The lifecycle GHG profile of the produced jet fuel is 95% of conventional jet fuel. Without converting the fuel gas to a low carbon fuel gas, the emissions would be 108% of conventional jet fuel and without any GHG mitigation, the profile would be 206%. Oil prices greater than $120 per barrel are required to reach a targeted internal rate of return on equity (IRROE) of 12%. Although capital expenditure is much less than if a greenfield facility was built, the relatively small size of the plant, assumed coal price, and the CTL risk profile used in the economic assumptions lead to a high cost of production. Assuming more favorable factors, the economic oil price could be reduced to $78 per barrel with GHG mitigation and $55 per barrel with no GHG mitigation.« less

Exhaust gas purification system for lean burn engine

DOEpatents

Haines, Leland Milburn

2002-02-19

An exhaust gas purification system for a lean burn engine includes a thermal mass unit and a NO.sub.x conversion catalyst unit downstream of the thermal mass unit. The NO.sub.x conversion catalyst unit includes at least one catalyst section. Each catalyst section includes a catalytic layer for converting NO.sub.x coupled to a heat exchanger. The heat exchanger portion of the catalyst section acts to maintain the catalytic layer substantially at a desired temperature and cools the exhaust gas flowing from the catalytic layer into the next catalytic section in the series. In a further aspect of the invention, the exhaust gas purification system includes a dual length exhaust pipe upstream of the NO.sub.x conversion catalyst unit. The dual length exhaust pipe includes a second heat exchanger which functions to maintain the temperature of the exhaust gas flowing into the thermal mass downstream near a desired average temperature.

Gas Foil Bearings for Space Propulsion Nuclear Electric Power Generation

NASA Technical Reports Server (NTRS)

Howard, Samuel A.; DellaCorte, Christopher

2006-01-01

The choice of power conversion technology is critical in directing the design of a space vehicle for the future NASA mission to Mars. One candidate design consists of a foil bearing supported turbo alternator driven by a helium-xenon gas mixture heated by a nuclear reactor. The system is a closed-loop, meaning there is a constant volume of process fluid that is sealed from the environment. Therefore, foil bearings are proposed due to their ability to use the process gas as a lubricant. As such, the rotor dynamics of a foil bearing supported rotor is an important factor in the eventual design. The current work describes a rotor dynamic analysis to assess the viability of such a system. A brief technology background, assumptions, analyses, and conclusions are discussed in this report. The results indicate that a foil bearing supported turbo alternator is possible, although more work will be needed to gain knowledge about foil bearing behavior in helium-xenon gas.

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

Studies on biomass char gasification and dynamics

NASA Astrophysics Data System (ADS)

You, Zhanping; You, Shijun; Ma, Xiaoyan

2018-01-01

The gasification performances of two kinds of biomass char by experiment methods are studied, including conversion rate and gasification gas component with temperature and time. Experimental results show that gasification temperature has important effects on the conversion rate and gas component. In the range of experimental temperature, char conversion rates are no more than 30.0%. The apparent activation energies and apparent reaction frequency factors of two biomass chars are obtained through kinetic studies.

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.

Effect of process design and operating parameters on aerobic methane oxidation in municipal WWTPs.

PubMed

Daelman, Matthijs R J; Van Eynde, Tamara; van Loosdrecht, Mark C M; Volcke, Eveline I P

2014-12-01

Methane is a potent greenhouse gas and its emission from municipal wastewater treatment plants (WWTPs) should be prevented. One way to do this is to promote the biological conversion of dissolved methane over stripping in aeration tanks. In this study, the well-established Activated Sludge Model n°1 (ASM1) and Benchmark Simulation Model n°1 (BSM1) were extended to study the influence of process design and operating parameters on biological methane oxidation. The aeration function used in BSM 1 was upgraded to more accurately describe gas-liquid transfer of oxygen and methane in aeration tanks equipped with subsurface aeration. Dissolved methane could be effectively removed in an aeration tank at an aeration rate that is in agreement with optimal effluent quality. Subsurface bubble aeration proved to be better than surface aeration, while a CSTR configuration was superior to plug flow conditions in avoiding methane emissions. The conversion of methane in the activated sludge tank benefits from higher methane concentrations in the WWTP's influent. Finally, if an activated sludge tank is aerated with methane containing off-gas, a limited amount of methane is absorbed and converted in the mixed liquor. This knowledge helps to stimulate the methane oxidizing capacity of activated sludge in order to abate methane emissions from wastewater treatment to the atmosphere. Copyright © 2014 Elsevier Ltd. All rights reserved.

Catalyst for selective conversion of synthesis gas and method of making the catalyst

DOEpatents

Dyer, Paul N.; Pierantozzi, Ronald

1986-01-01

A Fischer-Tropsch (F-T) catalyst, a method of making the catalyst and an F-T process utilizing the catalyst by which synthesis gas, particularly carbon-monoxide rich synthesis gas is selectively converted to higher hydrocarbons of relatively narrow carbon number range. In general, the selective and notably stable catalyst, consists of an inert carrier first treated with a Group IV B metal compound (such as zirconium or titanium), preferably an alkoxide compound, and subsequently treated with an organic compound of an F-T metal catalyst, such as cobalt, iron or ruthenium carbonyl. Reactions with air and water and calcination are specifically avoided in the catalyst preparation procedure.

A space-based combined thermophotovoltaic electric generator and gas laser solar energy conversion system

NASA Technical Reports Server (NTRS)

Yesil, Oktay

1989-01-01

This paper describes a spaceborne energy conversion system consisting of a thermophotovoltaic electric generator and a gas laser. As a power source for the converson, the system utilizes an intermediate blackbody cavity heated to a temperature of 2000-2400 K by concentrated solar radiation. A double-layer solar cell of GaAs and Si forms a cylindrical surface concentric to this blackbody cavity, receiving the blackbody radiation and converting it into electricity with cell conversion efficiency of 50 percent or more. If the blackbody cavity encloses a laser medium, the blackbody radiation can also be used to simultaneously pump a lasing gas. The feasibility of blackbody optical pumping at 4.3 microns in a CO2-He gas mixture was experimentally demonstrated.

Nitrogen removal characteristics analyzed with gas and microbial community in thermophilic aerobic digestion for piggery waste treatment.

PubMed

Lee, J W; Lee, H W; Kim, S W; Lee, S Y; Park, Y K; Han, J H; Choi, S I; Yi, Y S; Yun, Z

2004-01-01

In order to characterize the nitrogen conversion characteristics in a thermophilic aerobic digestion (TAD) system, a laboratory study has been conducted with the analysis of effluent gas and microbial community in the sludge samples. The lab TAD system was operated with HRT of 3 days and 60 degrees C. Based on the nitrogen mass balance, it has been found that about 2/3 of the daily load of nitrogen was converted to the gaseous form of nitrogen whereas cellular transformation and unmetabolized nitrogen accounted for about 1/3. Among the gaseous nitrogen transformation, significant amount of influent nitrogen had been converted to N2 gas (29% of influent N) and N2O (9% of influent N). Ammonia conversion was only 28% of influent N. The detection of N2O gas is a clear indication of the biological nitrogen reduction process in the thermophilic aerobic digester. No conclusive evidence for the existence of aerobic deammonification has been found. The microbial community analysis showed that thermophilic bacteria such as Bacillus thermocloacae, Bacillus sp. and Clostridial groups dominated in this TAD reactor. The diverse microbial community in TAD sludge may play an important role in removing both strong organics and nitrogen from piggery waste.

Microbially-Enhanced Coal Bed Methane: Strategies for Increased Biogenic Production

NASA Astrophysics Data System (ADS)

Davis, K.; Barhart, E. P.; Schweitzer, H. D.; Cunningham, A. B.; Gerlach, R.; Hiebert, R.; Fields, M. W.

2014-12-01

Coal is the largest fossil fuel resource in the United States. Most of this coal is deep in the subsurface making it costly and potentially dangerous to extract. However, in many of these deep coal seams, methane, the main component of natural gas, has been discovered and successfully harvested. Coal bed methane (CBM) currently accounts for approximately 7.5% of the natural gas produced in the U.S. Combustion of natural gas produces substantially less CO2 and toxic emissions (e.g. heavy metals) than combustion of coal or oil thereby making it a cleaner energy source. In the large coal seams of the Powder River Basin (PRB) in southeast Montana and northeast Wyoming, CBM is produced almost entirely by biogenic processes. The in situ conversion of coal to CBM by the native microbial community is of particular interest for present and future natural gas sources as it provides the potential to harvest energy from coal seams with lesser environmental impacts than mining and burning coal. Research at Montana State University has shown the potential for enhancing the subsurface microbial processes that produce CBM. Long-term batch enrichments have investigated the methane enhancement potential of yeast extract as well as algal and cyanobacterial biomass additions with increased methane production observed with all three additions when compared to no addition. Future work includes quantification of CBM enhancement and normalization of additions. This presentation addresses the options thus far investigated for increasing CBM production and the next steps for developing the enhanced in situ conversion of coal to CBM.

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

Dong, Tao; Fei, Qiang; Genelot, Marie

In light of the availability of low-cost methane (CH 4) derived from natural gas and biogas along with increasing concerns of the greenhouse gas emissions, the production of alternative liquid biofuels directly from CH 4 is a promising approach to capturing wasted energy. A novel biorefinery concept integrating biological conversion of CH 4 to microbial lipids together with lipid extraction and generation of hydrocarbon fuels is demonstrated in this study for the first time. An aerobic methanotrophic bacterium, Methylomicrobium buryatense capable of using CH 4 as the sole carbon source was selected on the basis of genetic tractability, cultivation robustness,more » and ability to accumulate phospholipids in membranes. A maximum fatty acid content of 10% of dry cell weight was obtained in batch cultures grown in a continuous gas sparging fermentation system. Although phospholipids are not typically considered as a good feedstock for upgrading to hydrocarbon fuels, we set out to demonstrate that using a combination of novel lipid extraction methodology with advanced catalyst design, we could prove the feasibility of this approach. Up to 95% of the total fatty acids from membrane-bound phospholipids were recovered by a two-stage pretreatment method followed by hexane extraction of the aqueous hydrolysate. The upgrading of extracted lipids was then demonstrated in a hydrodeoxygeation process using palladium on silica as a catalyst. Lipid conversion in excess of 99% was achieved, with a full selectivity to hydrocarbons. Lastly, the final hydrocarbon mixture is dominated by 88% pentadecane (C 15H 32) based on decarbonylation/decarboxylation and hydrogenation of C16 fatty acids, indicating that a biological gas-to-liquid fuel (Bio-GTL) process is technically feasible.« less

Improving Secondary Organic Aerosol (SOA) Models using Global Sensitivity Analysis and by Comparison to Chamber Data.

NASA Astrophysics Data System (ADS)

Miller, D. O.; Brune, W. H.

2017-12-01

Accurate estimates of secondary organic aerosol (SOA) from atmospheric models is a major research challenge due to the complexity of the chemical and physical processes involved in the SOA formation and continuous aging. The primary uncertainties of SOA models include those associated with the formation of gas-phase products, the conversion between gas phase and particle phase, the aging mechanisms of SOA, and other processes related to the heterogeneous and particle-phase reactions. To address this challenge, we us a modular modeling framework that combines both simple and near-explicit gas-phase reactions and a two-dimensional volatility basis set (2D-VBS) to simulate the formation and evolution of SOA. Global sensitivity analysis is used to assess the relative importance of the model input parameters. In addition, the model is compared to the measurements from the Focused Isoprene eXperiment at the California Institute of Technology (FIXCIT).

Cost effectiveness of converting to alternative motor vehicle fuels. A technical assistance study for the City of Longview

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

McCoy, G.A.

1983-11-18

The City of Longview can obtain significant fuel savings benefits by converting a portion of their vehicle fleet to operate on either compressed natural gas (CNG) or liquid petroleum gas (LPG) fuels. The conversion of 41 vehicles including police units, sedans, pickups, and light duty trucks to CNG use would offset approximately 47% of the city's 1982 gasoline consumption. The CNG conversion capital outlay of $115,000 would be recovered through fuel cost reductions. The Cascade Natural Gas Corporation sells natural gas under an interruptible tariff for $0.505 per therm, equivalent to slightly less than one gallon of gasoline. The citymore » currently purchases unleaded gasoline at $1.115 per gallon. A payback analysis indicates that 39.6 months are required for the CNG fuel savings benefits to offset the initial or first costs of the conversion. The conversion of fleet vehicles to liquid petroleum gas (LPG) or propane produces comparable savings in vehicle operating costs. The conversion of 59 vehicles including police units, pickup and one ton trucks, street sweepers, and five cubic yard dump trucks would cost approximately $59,900. The annual purchase of 107,000 gallons of propane would offset the consumption of 96,300 gallons of gasoline, or approximately 67% of the city's 1982 usage. Propane is currently retailing for $0.68 to $0.74 per gallon. A payback analysis indicates that 27.7 months are required for the fuel savings benefits to offset the initial LPG conversion costs.« less

Simulation study on combustion of biomass

NASA Astrophysics Data System (ADS)

Zhao, M. L.; Liu, X.; Cheng, J. W.; Liu, Y.; Jin, Y. A.

2017-01-01

Biomass combustion is the most common energy conversion technology, offering the advantages of low cost, low risk and high efficiency. In this paper, the transformation and transfer of biomass in the process of combustion are discussed in detail. The process of furnace combustion and gas phase formation was analyzed by numerical simulation. The experimental results not only help to optimize boiler operation and realize the efficient combustion of biomass, but also provide theoretical basis for the improvement of burner technology.

Design and analysis of siloxanes removal by adsorption from landfill gas for waste-to-energy processes.

PubMed

Elwell, Anthony C; Elsayed, Nada H; Kuhn, John N; Joseph, Babu

2018-03-01

Separation of volatile methyl siloxanes from landfill gas using fixed adsorption beds was modeled with the objective of identifying appropriate technology and the economics associated with this purification step. A general adsorption model assuming plug flow and radial symmetry was developed and used to conduct a parametric sweep of 162 unique cases. The varied parameters were adsorbent type (activated carbon and silica gel), bed height (3.05-9.15 m/10-30 ft), inlet siloxane concentration (5-15 mg/m 3 ), moisture content (0-100% relative humidity at STP or RH), and siloxane tolerance limit (0.094-9.4 mg/m 3 ) that correlated to three distinct energy conversion technologies (electricity production using engines or fuels cells or catalytic conversion to liquid hydrocarbon fuels). Due to the detrimental effect of RH on siloxane absorption, the maximum allowable moisture content of LFG before purification is 50% RH and moisture removal processes are also required. The design calculations using a selected case study show that the adsorption bed height required needed for 6 months minimum breakthrough time for catalytic fuel production is twice that for engine applications. Fuel cell applications require 3 times the bed height compared to engine applications. However, the purification costs amounted to 94%, 16% and 52% of recovered product value for engine, liquefaction, and fuel cell applications, respectively indicating the need for a high value product to justify purification costs. The approaches and conclusions can be extended to specific process conditions for landfill gas purification and to other processes that use biogas produced from waste as a feedstock. Copyright © 2017 Elsevier Ltd. All rights reserved.

Risk analysis of a biomass combustion process using MOSAR and FMEA methods.

PubMed

Thivel, P-X; Bultel, Y; Delpech, F

2008-02-28

Thermal and chemical conversion processes that convert in energy the sewage sludge, pasty waste and other pre-processed waste are increasingly common, for economic and ecological reasons. Fluidized bed combustion is currently one of the most promising methods of energy conversion, since it burns biomass very efficiently, and produces only very small quantities of sulphur and nitrogen oxides. The hazards associated with biomass combustion processes are fire, explosion and poisoning from the combustion gases (CO, etc.). The risk analysis presented in this paper uses the MADS-MOSAR methodology, applied to a semi-industrial pilot scheme comprising a fluidization column, a conventional cyclone, two natural gas burners and a continuous supply of biomass. The methodology uses a generic approach, with an initial macroscopic stage where hazard sources are identified, scenarios for undesired events are recognized and ranked using a grid of SeverityxProbability and safety barriers suggested. A microscopic stage then analyzes in detail the major risks identified during the first stage. This analysis may use various different tools, such as HAZOP, FMEA, etc.: our analysis is based on FMEA. Using MOSAR, we were able to identify five subsystems: the reactor (fluidized bed and centrifuge), the fuel and biomass supply lines, the operator and the environment. When we drew up scenarios based on these subsystems, we found that malfunction of the gas supply burners was a common trigger in many scenarios. Our subsequent microscopic analysis, therefore, focused on the burners, looking at the ways they failed, and at the effects and criticality of those failures (FMEA). We were, thus, able to identify a number of critical factors such as the incoming gas lines and the ignition electrode.

Conversion of laser energy to gas kinetic energy

NASA Technical Reports Server (NTRS)

Caledonia, G. E.

1977-01-01

Techniques for the gas-phase absorption of laser energy with ultimate conversion to heat or directed kinetic energy are reviewed. It is shown that the efficiency of resonance absorption by the vibration/rotation bands of the working gas can be enhanced by operating at sufficiently high pressures so that the linewidths of the absorbing transition exceed the line spacing. Within this limit, the gas can absorb continuously over the full spectral region of the band, and bleaching can be minimized since the manifold of molecular vibrational levels can simultaneously absorb the laser radiation.

Simulation of Water Gas Shift Zeolite Membrane Reactor

NASA Astrophysics Data System (ADS)

Makertiharta, I. G. B. N.; Rizki, Z.; Zunita, Megawati; Dharmawijaya, P. T.

2017-07-01

The search of alternative energy sources keeps growing from time to time. Various alternatives have been introduced to reduce the use of fossil fuel, including hydrogen. Many pathways can be used to produce hydrogen. Among all of those, the Water Gas Shift (WGS) reaction is the most common pathway to produce high purity hydrogen. The WGS technique faces a downstream processing challenge due to the removal hydrogen from the product stream itself since it contains a mixture of hydrogen, carbon dioxide and also the excess reactants. An integrated process using zeolite membrane reactor has been introduced to improve the performance of the process by selectively separate the hydrogen whilst boosting the conversion. Furthermore, the zeolite membrane reactor can be further improved via optimizing the process condition. This paper discusses the simulation of Zeolite Membrane Water Gas Shift Reactor (ZMWGSR) with variation of process condition to achieve an optimum performance. The simulation can be simulated into two consecutive mechanisms, the reaction prior to the permeation of gases through the zeolite membrane. This paper is focused on the optimization of the process parameters (e.g. temperature, initial concentration) and also membrane properties (e.g. pore size) to achieve an optimum product specification (concentration, purity).

Particle behavior and char burnout mechanisms under pressurized combustion conditions

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

Bauer, C.M.; Spliethoff, H.; Hein, K.R.G.

Combined cycle systems with coal-fired gas turbines promise highest cycle efficiencies for this fuel. Pressurized pulverized coal combustion, in particular, yields high cycle efficiencies due to the high flue gas temperatures possible. The main problem, however, is to ensure a flue gas clean enough to meet the high gas turbine standards with a dirty fuel like coal. On the one hand, a profound knowledge of the basic chemical and physical processes during fuel conversion under elevated pressures is required whereas on the other hand suitable hot gas cleaning systems need to be developed. The objective of this work was tomore » provide experimental data to enable a detailed description of pressurized coal combustion processes. A series of experiments were performed with two German hvb coals, Ensdorf and Goettelborn, and one German brown coal, Garzweiler, using a semi-technical scale pressurized entrained flow reactor. The parameters varied in the experiments were pressure, gas temperature and bulk gas oxygen concentration. A two-color pyrometer was used for in-situ determination of particle surface temperatures and particle sizes. Flue gas composition was measured and solid residue samples taken and subsequently analyzed. The char burnout reaction rates were determinated varying the parameters pressure, gas temperature and initial oxygen concentration. Variation of residence time was achieved by taking the samples at different points along the reaction zone. The most influential parameters on char burnout reaction rates were found to be oxygen partial pressure and fuel volatile content. With increasing pressure the burn-out reactions are accelerated and are mostly controlled by product desorption and pore diffusion being the limiting processes. The char burnout process is enhanced by a higher fuel volatile content.« less

Examination and evaluation of the use of screen heaters for the measurement of the high temperature pyrolysis kinetics of polyethene and polypropene

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

Westerhout, R.W.J.; Balk, R.H.P.; Meijer, R.

1997-08-01

A screen heater with a gas sweep was developed and applied to study the pyrolysis kinetics of low density polyethene (LDPE) and polypropene (PP) at temperatures ranging from 450 to 530 C. The aim of this study was to examine the applicability of screen heaters to measure these kinetics. On-line measurement of the rate of volatiles formation using a hydrocarbon analyzer was applied to enable the determination of the conversion rate over the entire conversion range on the basis of a single experiment. Another important feature of the screen heater used in this study is the possibility to measure pyrolysismore » kinetics under nearly isothermal conditions. The kinetic constants for LDPE and PP pyrolysis were determined, using a first order model to describe the conversion rate in the 70--90% conversion range and the random chain dissociation model for the entire conversion range. In addition to the experimental work two single particle models have been developed which both incorporate a mass and a (coupled) enthalpy balance, which were used to assess the influence of internal and external heat transfer processes on the pyrolysis process. The first model assumes a variable density and constant volume during the pyrolysis process, whereas the second model assumes a constant density and a variable volume. An important feature of these models is that they can accommodate kinetic models for which no analytical representation of the pyrolysis kinetics is available.« less

Carbon Dioxide-Free Hydrogen Production with Integrated Hydrogen Separation and Storage.

PubMed

Dürr, Stefan; Müller, Michael; Jorschick, Holger; Helmin, Marta; Bösmann, Andreas; Palkovits, Regina; Wasserscheid, Peter

2017-01-10

An integration of CO 2 -free hydrogen generation through methane decomposition coupled with hydrogen/methane separation and chemical hydrogen storage through liquid organic hydrogen carrier (LOHC) systems is demonstrated. A potential, very interesting application is the upgrading of stranded gas, for example, gas from a remote gas field or associated gas from off-shore oil drilling. Stranded gas can be effectively converted in a catalytic process by methane decomposition into solid carbon and a hydrogen/methane mixture that can be directly fed to a hydrogenation unit to load a LOHC with hydrogen. This allows for a straight-forward separation of hydrogen from CH 4 and conversion of hydrogen to a hydrogen-rich LOHC material. Both, the hydrogen-rich LOHC material and the generated carbon on metal can easily be transported to destinations of further industrial use by established transport systems, like ships or trucks. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hanford Low-Activity Waste Processing: Demonstration of the Off-Gas Recycle Flowsheet - 13443

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

Ramsey, William G.; Esparza, Brian P.

2013-07-01

Vitrification of Hanford Low-Activity Waste (LAW) is nominally the thermal conversion and incorporation of sodium salts and radionuclides into borosilicate glass. One key radionuclide present in LAW is technetium-99. Technetium-99 is a low energy, long-lived beta emitting radionuclide present in the waste feed in concentrations on the order of 1-10 ppm. The long half-life combined with a high solubility in groundwater results in technetium-99 having considerable impact on performance modeling (as potential release to the environment) of both the waste glass and associated secondary waste products. The current Hanford Tank Waste Treatment and Immobilization Plant (WTP) process flowsheet calls formore » the recycle of vitrification process off-gas condensates to maximize the portion of technetium ultimately immobilized in the waste glass. This is required as technetium acts as a semi-volatile specie, i.e. considerable loss of the radionuclide to the process off-gas stream can occur during the vitrification process. To test the process flowsheet assumptions, a prototypic off-gas system with recycle capability was added to a laboratory melter (on the order of 1/200 scale) and testing performed. Key test goals included determination of the process mass balance for technetium, a non-radioactive surrogate (rhenium), and other soluble species (sulfate, halides, etc.) which are concentrated by recycling off-gas condensates. The studies performed are the initial demonstrations of process recycle for this type of liquid-fed melter system. This paper describes the process recycle system, the waste feeds processed, and experimental results. Comparisons between data gathered using process recycle and previous single pass melter testing as well as mathematical modeling simulations are also provided. (authors)« less

Report of National Institute for Resources and Environment. No. 5: Study on direct liquefaction of woody biomass

NASA Astrophysics Data System (ADS)

Ogi, Tomoko; Yokoyama, Shinya; Minowa, Tomoaki; Dote, Yutaka; Koguchi, Katsuya

1993-03-01

Various researches on the production of liquid fuels from biomass were undertaken. Carbon monoxide and/or hydrogen were used in most cases, while processes using a little or none of these reducing gas were investigated. The following results on thermochemical conversion of wood biomass are presented, in which wood is reacted in aqueous solution in the presence of an alkali catalyst without reducing gases, which yielded a liquid product: (1) the optimum reaction condition is determined from systematic studies carried out with reaction parameter and variety of catalyst; (2) the optimum organic solvents are determined from investigations concerning production of heavy oil which is easily separable from an aqueous layer; (3) the effectiveness of the repeated use of reaction solvent is indicated by experiments in which water or a 2-propanol/water mixture is used repeatedly as a reaction solvent; and (4) heavy oil obtained by the liquefaction process was analyzed by (1) H-NMR (Nuclear Magnetic Resonance), GC (Gas Chromatography) - MS (Mass Spectrometry), and acid-base extraction. The liquefaction technology may be evaluated as one of the highly promising biomass conversion technologies, although some technical problems, such as separation or upgrading of heavy oils need to be solved. For the promotion of a total system, in which biomass is planted and grown and then the biomass is used as fuel and/or chemicals, further development of technologies are needed not only for conversion itself but also for plantation, afforestation, and irrigation.

Hydrogen Production by Steam Reforming of Natural Gas Over Vanadium-Nickel-Alumina Catalysts.

PubMed

Yoo, Jaekyeong; Park, Seungwon; Song, Ji Hwan; Song, In Kyu

2018-09-01

A series of vanadium-nickel-alumina (xVNA) catalysts were prepared by a single-step sol-gel method with a variation of vanadium content (x, wt%) for use in the hydrogen production by steam reforming of natural gas. The effect of vanadium content on the physicochemical properties and catalytic activities of xVNA catalysts in the steam reforming of natural gas was investigated. It was found that natural gas conversion and hydrogen yield showed volcano-shaped trends with respect to vanadium content. It was also revealed that natural gas conversion and hydrogen yield increased with decreasing nickel crystallite size.

Catalysts and process for liquid hydrocarbon fuel production

DOEpatents

White, Mark G; Liu, Shetian

2014-12-09

The present invention provides a novel process and system in which a mixture of carbon monoxide and hydrogen synthesis gas, or syngas, is converted into hydrocarbon mixtures composed of high quality gasoline components, aromatic compounds, and lower molecular weight gaseous olefins in one reactor or step. The invention utilizes a novel molybdenum-zeolite catalyst in high pressure hydrogen for conversion, as well as a novel rhenium-zeolite catalyst in place of the molybdenum-zeolite catalyst, and provides for use of the novel catalysts in the process and system of the invention.

Biofuels in China.

PubMed

Tan, Tianwei; Yu, Jianliang; Lu, Jike; Zhang, Tao

2010-01-01

The Chinese government is stimulating the biofuels development to replace partially fossil fuels in the transport sector, which can enhance energy security, reduce greenhouse gas emissions, and stimulate rural development. Bioethanol, biodiesel, biobutanol, biogas, and biohydrogen are the main biofuels developed in China. In this chapter, we mainly present the current status of biofuel development in China, and illustrate the issues of feedstocks, food security and conversion processes.

PROCESS FOR PRODUCING URANIUM HEXAFLUORIDE

DOEpatents

Fowler, R.D.

1957-10-22

A process for the production of uranium hexafluoride from the oxides of uranium is reported. In accordance with the method the higher oxides of uranium may be reduced to uranium dioxide (UO/sub 2/), the latter converted into uranium tetrafluoride by reaction with hydrogen fluoride, and the UF/sub 4/ convented to UF/sub 6/ by reaction with a fluorinating agent. The UO/sub 3/ or U/sub 3/O/sub 8/ is placed in a reaction chamber in a copper boat or tray enclosed in a copper oven, and heated to 500 to 650 deg C while hydrogen gas is passed through the oven. The oven is then swept clean of hydrogen and the water vapor formed by means of nitrogen and then while continuing to maintain the temperature between 400 and 600 deg C, anhydrous hydrogen fluoride is passed through. After completion of the conversion to uranium tetrafluoride, the temperature of the reaction chamber is lowered to ahout 400 deg C, and elemental fluorine is used as the fluorinating agent for the conversion of UF/sub 4/ into UF/sub 6/. The fluorine gas is passed into the chamber, and the UF/sub 6/ formed passes out and is delivered to a condenser.

Fuel purpose hydrotreating of sunflower oil on CoMo/Al2O3 catalyst.

PubMed

Krár, Márton; Kovács, Sándor; Kalló, Dénes; Hancsók, Jeno

2010-12-01

The importance of the economical production and usage of new generation biofuels, the so-called bio gas oil (paraffins from triglycerides) and the results of the investigation for their productability on the CoMo/Al(2)O(3) catalyst, which was activated by reduction, are presented. The conversion of triglycerides, the yield of total organic fractions and the target product, furthermore the type and ratio of deoxygenation reactions were determined as a function of process parameters. The advantageous process parameters were found (380 degrees C, 40-60 bar, 500-600 Nm(3)/m(3) H(2)/sunflower oil ratio, 1.0 h(-1)), where the conversion of triglycerides was 100% and the yield of the target fraction [high paraffin containing (>99%) gas oil boiling range product] was relatively high (73.7-73.9%). The deoxygenation of triglycerides the reduction as well as the decarboxylation/decarbonylation reactions took place. The yield of the target fractions did not achieve the theoretical values (81.4-86.5%). That is why it is necessary to separate the target fraction and recirculate the heavy fraction. 2010 Elsevier Ltd. All rights reserved.

Definitional mission report: NAPCOR thermal-power-conversion project, Philippines. Export trade information

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

Not Available

1991-11-01

The National Power Corporation (NAPCOR) of Philippines has requested the Trade and Development Program (TDP) to fund a study to evaluate the technical and economic feasibility of converting its existing oil and coal fired power plants to natural gas. The decision to undertake the study resulted from preliminary information on a large gas find off the coast of Palawan island. However, a second exploration well has come up dry. Now, the conversion of the existing power plants to natural gas seems very questionable. Even if the proven gas reserves prove to be commercially viable, the gas will not be availablemore » until 1998 or later for utilization. At that time several of NAPCOR's plants would have aged further, the political and economic situation in Philippines could have altered significantly, possibly improved, private power companies might be able to use the gas more efficiently by building state-of-the-art combined cycle power plants which will make more economic sense than converting existing old boilers to natural gas. In addition, most of the existing power equipment was manufactured by Japanese and/or European firms. It makes sense for NAPCOR to solicit services from these firms if it decides to go ahead with the implementation of the power plant conversion project. The potential for any follow on work for U.S. businesses is minimal to zero in the thermal conversion project. Therefore, at this time, TDP funding for the feasibility would be premature and not recommended.« less

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.

Conventional and fast pyrolysis of automobile shredder residues (ASR).

PubMed

Zolezzi, Marcello; Nicolella, Cristiano; Ferrara, Sebastiano; Iacobucci, Cesare; Rovatti, Mauro

2004-01-01

This work aims at comparing performance and product yields in conventional pyrolysis and fast pyrolysis of automotive shredded residues. In both processes, carbon conversion to gaseous and liquid products was more than 80%. Gas production was maximised in conventional pyrolysis (about 35% by weight of the initial ASR weight), while fast pyrolysis led to an oil yield higher than 55%. Higher heating values (HHV) of both conventional pyrolysis gas and fast pyrolysis oil increased from 8.8 to 25.07 MJ/Nm3 and from 28.8 and 36.27 MJ/kg with increasing pyrolysis temperature. Copyright 2004 Elsevier Ltd.

The mechanism of explosive emission excitation in thermionic energy conversion processes

NASA Astrophysics Data System (ADS)

Bulyga, A. V.

A study has been made of the mechanism of explosive electron emission in vacuum thermionic converters induced by thermionic currents in the case of the anomalous Richardson effect. The latter is associated with a spotted emitting surface and temperature fluctuations. In order to account for one of the components of the electrode potential difference, it is proposed that allowance be made for the difference between the polarization signal velocity in a dense metal electron gas and that in the electron-ion gas of the electrode gap. Ways to achieve explosive emission in real thermionic converters are discussed.

Fracture Behaviour of Plasma Sprayed Thermal Barrier Coatings

NASA Astrophysics Data System (ADS)

Malzbender, Jürgen; Wakui, Takashi; Wessel, Egbert; Steinbrech, Rolf W.

Thermal barrier coatings (TBCs) of plasma sprayed yttria stabilised zirconia (YSZ) are increasingly utilised for heat exposed components of advanced gas turbines1,2. An important reason for the application of zirconia coatings is the low thermal conductivity of this ceramic material which is further diminished in a TBC by the high concentration of spraying induced microstructural defects, e.g. crack-shaped defects between and within the spraying splats. Thus with TBCs on gas cooled turbine components stiff temperature gradients can be realised as an important prerequisite for an increased thermal efficiency of the energy conversion process.

metAlignID: a high-throughput software tool set for automated detection of trace level contaminants in comprehensive LECO two-dimensional gas chromatography time-of-flight mass spectrometry data.

PubMed

Lommen, Arjen; van der Kamp, Henk J; Kools, Harrie J; van der Lee, Martijn K; van der Weg, Guido; Mol, Hans G J

2012-11-09

A new alternative data processing tool set, metAlignID, is developed for automated pre-processing and library-based identification and concentration estimation of target compounds after analysis by comprehensive two-dimensional gas chromatography with mass spectrometric detection. The tool set has been developed for and tested on LECO data. The software is developed to run multi-threaded (one thread per processor core) on a standard PC (personal computer) under different operating systems and is as such capable of processing multiple data sets simultaneously. Raw data files are converted into netCDF (network Common Data Form) format using a fast conversion tool. They are then preprocessed using previously developed algorithms originating from metAlign software. Next, the resulting reduced data files are searched against a user-composed library (derived from user or commercial NIST-compatible libraries) (NIST=National Institute of Standards and Technology) and the identified compounds, including an indicative concentration, are reported in Excel format. Data can be processed batch wise. The overall time needed for conversion together with processing and searching of 30 raw data sets for 560 compounds is routinely within an hour. The screening performance is evaluated for detection of pesticides and contaminants in raw data obtained after analysis of soil and plant samples. Results are compared to the existing data-handling routine based on proprietary software (LECO, ChromaTOF). The developed software tool set, which is freely downloadable at www.metalign.nl, greatly accelerates data-analysis and offers more options for fine-tuning automated identification toward specific application needs. The quality of the results obtained is slightly better than the standard processing and also adds a quantitative estimate. The software tool set in combination with two-dimensional gas chromatography coupled to time-of-flight mass spectrometry shows great potential as a highly-automated and fast multi-residue instrumental screening method. Copyright © 2012 Elsevier B.V. All rights reserved.

Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 5: Combined gas-steam turbine cycles. [energy conversion efficiency in electric power plants

NASA Technical Reports Server (NTRS)

Amos, D. J.; Foster-Pegg, R. W.; Lee, R. M.

1976-01-01

The energy conversion efficiency of gas-steam turbine cycles was investigated for selected combined cycle power plants. Results indicate that it is possible for combined cycle gas-steam turbine power plants to have efficiencies several point higher than conventional steam plants. Induction of low pressure steam into the steam turbine is shown to improve the plant efficiency. Post firing of the boiler of a high temperature combined cycle plant is found to increase net power but to worsen efficiency. A gas turbine pressure ratio of 12 to 1 was found to be close to optimum at all gas turbine inlet temperatures that were studied. The coal using combined cycle plant with an integrated low-Btu gasifier was calculated to have a plant efficiency of 43.6%, a capitalization of $497/kW, and a cost of electricity of 6.75 mills/MJ (24.3 mills/kwh). This combined cycle plant should be considered for base load power generation.

State-of-the-art survey of joinability of materials for OTEC heat exchangers

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

Beaver, R. J.

1978-12-01

Literature and industrial sources were surveyed to assess, on the basis of apparent economics and reliability, the joinability of both shell-and-tube and compact ocean thermal energy conversion (OTEC) heat exchangers. A no-leak requirement is mandatory to prevent mixing seawater and the ammonia working fluid. The operating temperature range considered is 7 to 28/sup 0/C (45 to 82/sup 0/F). Materials evaluated were aluminum, titanium, copper--nickel, AL-6X austenitic stainless steel, singly and in combination with steel and concrete. Many types of welding and brazing processes, roller expansion, magnaforming, O-ring sealing, and adhesive bonding were considered. The automatic gas tungsten-arc welding process andmore » explosion welding processes are the only two joining processes that now appear to offer the high reliability required of no-leak shell-and-tube heat exchangers. Of these two processes, the gas tungsten-arc welding process appears to be the more economically attractive.« less

Method of production of pure hydrogen near room temperature from aluminum-based hydride materials

DOEpatents

Pecharsky, Vitalij K.; Balema, Viktor P.

2004-08-10

The present invention provides a cost-effective method of producing pure hydrogen gas from hydride-based solid materials. The hydride-based solid material is mechanically processed in the presence of a catalyst to obtain pure gaseous hydrogen. Unlike previous methods, hydrogen may be obtained from the solid material without heating, and without the addition of a solvent during processing. The described method of hydrogen production is useful for energy conversion and production technologies that consume pure gaseous hydrogen as a fuel.

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

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

A GIS-based Model for Natural Gas Data Conversion

NASA Astrophysics Data System (ADS)

Bitik, E.; Seker, D. Z.; Denli, H. H.

2014-12-01

In Turkey gas utility sector has undergone major changes in terms of increased competition between gas providers, efforts in improving services, and applying new technological solutions. This paper discusses the challenges met by gas companies to switch from long workflows of gas distribution, sales and maintenance into IT driven efficient management of complex information both spatially and non-spatially. The aim of this study is migration of all gas data and information into a GIS environment in order to manage and operate all infrastructure investments with a Utility Management System. All data conversion model for migration was designed and tested during the study. A flowchart is formed to transfer the old data layers to the new structure based on geodatabase.

US North Slope gas and Asian LNG markets

USGS Publications Warehouse

Attanasi, E.D.

1994-01-01

Prospects for export of liquified natural gas (LNG) from Alaska's North Slope are assessed. Projected market conditions to 2010 show that new LNG capacity beyond announced expansions will be needed to meet regional demand and that supplies will probably come from outside the region. The estimated delivered costs of likely suppliers show that Alaska North Slope gas will not be competitive. The alternative North Slope gas development strategies of transport and sale to the lower 48 states and use on the North Slope for either enhanced oil recovery or conversion to liquids are examined. The alternative options require delaying development until US gas prices increase, exhaustion of certain North Slope oil fields, or advances occur in gas to liquid fuels conversion technology. ?? 1995.

The Reduction of Lunar Regolith by Carbothermal Processing Using Methane

NASA Technical Reports Server (NTRS)

Balasubramaniam, R.; Hegde, U.; Gokoglu, S.

2010-01-01

The processing of lunar regolith for the production of oxygen is a key component of the In-Situ Resource Utilization plans Currently being developed by NASA. In the carbothermal process, a portion of the surface of the regolith in a container is heated by exposure to a heat source so that a small zone of molten regolith is established. A continuous flow of methane is maintained over the molten regolith zone. In this paper, we discuss the development of a chemical conversion model of the carbothermal process to predict the rate of production of carbon monoxide. Our model is based on a mechanism where methane pyrolyzes when it comes in contact with the surface of the hot molten regolith to form solid carbon and hydrogen gas. Carbon is deposited on the surface of the melt, and hydrogen is released into the gas stream above the melt surface. We assume that the deposited carbon mixes in the molten regolith and reacts with metal oxides in a reduction reaction by which gaseous carbon monoxide is liberated. Carbon monoxide bubbles through the melt and is released into the gas stream. It is further processed downstream to ultimately produce oxygen.

The Reduction of Lunar Regolith by Carbothermal Processing Using Methane

NASA Technical Reports Server (NTRS)

Balasubramaniam, R.; Gokoglu, S. A.; Hegde, U.

2010-01-01

The processing of lunar regolith for the production of oxygen is a key component of the In-Situ Resource Utilization plans currently being developed by NASA. In the carbothermal process, a portion of the surface of the regolith in a container is heated by exposure to a heat source so that a small zone of molten regolith is established. A continuous flow of methane is maintained over the molten regolith zone. In this paper, we discuss the development of a chemical conversion model of the carbothermal process to predict the rate of production of carbon monoxide. Our model is based on a mechanism where methane pyrolyzes when it comes in contact with the surface of the hot molten regolith to form solid carbon and hydrogen gas. Carbon is deposited on the surface of the melt, and hydrogen is released into the gas stream above the melt surface. We assume that the deposited carbon mixes in the molten regolith and reacts with metal oxides in a reduction reaction by which gaseous carbon monoxide is liberated. Carbon monoxide bubbles through the melt and is released into the gas stream. It is further processed downstream to ultimately produce oxygen.

Process for the production of liquid hydrocarbons

DOEpatents

Bhatt, Bharat Lajjaram; Engel, Dirk Coenraad; Heydorn, Edward Clyde; Senden, Matthijis Maria Gerardus

2006-06-27

The present invention concerns a process for the preparation of liquid hydrocarbons which process comprises contacting synthesis gas with a slurry of solid catalyst particles and a liquid in a reactor vessel by introducing the synthesis gas at a low level into the slurry at conditions suitable for conversion of the synthesis gas into liquid hydrocarbons, the solid catalyst particles comprising a catalytic active metal selected from cobalt or iron on a porous refractory oxide carrier, preferably selected from silica, alumina, titania, zirconia or mixtures thereof, the catalyst being present in an amount between 10 and 40 vol. percent based on total slurry volume liquids and solids, and separating liquid material from the solid catalyst particles by using a filtration system comprising an asymmetric filtration medium (the selective side at the slurry side), in which filtration system the average pressure differential over the filtration medium is at least 0.1 bar, in which process the particle size distribution is such that at least a certain amount of the catalyst particles is smaller than the average pore size of the selective layer of the filtration medium. The invention also comprises an apparatus to carry out the process described above.

Impact of wastewater infrastructure upgrades on the urban water cycle: Reduction in halogenated reaction byproducts following conversion from chlorine gas to ultraviolet light disinfection

USGS Publications Warehouse

Barber, Larry B.; Hladik, Michelle; Vajda, Alan M.; Fitzgerald, Kevin C.; Douville, Chris

2015-01-01

The municipal wastewater treatment facility (WWTF) infrastructure of the United States is being upgraded to expand capacity and improve treatment, which provides opportunities to assess the impact of full-scale operational changes on water quality. Many WWTFs disinfect their effluent prior to discharge using chlorine gas, which reacts with natural and synthetic organic matter to form halogenated disinfection byproducts (HDBPs). Because HDBPs are ubiquitous in chlorine-disinfected drinking water and have adverse human health implications, their concentrations are regulated in potable water supplies. Less is known about the formation and occurrence of HDBPs in disinfected WWTF effluents that are discharged to surface waters and become part of the de facto wastewater reuse cycle. This study investigated HDBPs in the urban water cycle from the stream source of the chlorinated municipal tap water that comprises the WWTF inflow, to the final WWTF effluent disinfection process before discharge back to the stream. The impact of conversion from chlorine-gas to low-pressure ultraviolet light (UV) disinfection at a full-scale (68,000 m3 d−1 design flow) WWTF on HDBP concentrations in the final effluent was assessed, as was transport and attenuation in the receiving stream. Nutrients and trace elements (boron, copper, and uranium) were used to characterize the different urban source waters, and indicated that the pre-upgrade and post-upgrade water chemistry was similar and insensitive to the disinfection process. Chlorinated tap water during the pre-upgrade and post-upgrade samplings contained 11 (mean total concentration = 2.7 μg L−1; n=5) and 10 HDBPs (mean total concentration = 4.5 μg L−1), respectively. Under chlorine-gas disinfection conditions 13 HDBPs (mean total concentration = 1.4 μg L−1) were detected in the WWTF effluent, whereas under UV disinfection conditions, only one HDBP was detected. The chlorinated WWTF effluent had greater relative proportions of nitrogenous, brominated, and iodinated HDBPs than the chlorinated tap water. Conversion of the WWTF to UV disinfection reduced the loading of HDBPs to the receiving stream by >90%.

Impact of wastewater infrastructure upgrades on the urban water cycle: Reduction in halogenated reaction byproducts following conversion from chlorine gas to ultraviolet light disinfection.

PubMed

Barber, Larry B; Hladik, Michelle L; Vajda, Alan M; Fitzgerald, Kevin C; Douville, Chris

2015-10-01

The municipal wastewater treatment facility (WWTF) infrastructure of the United States is being upgraded to expand capacity and improve treatment, which provides opportunities to assess the impact of full-scale operational changes on water quality. Many WWTFs disinfect their effluent prior to discharge using chlorine gas, which reacts with natural and synthetic organic matter to form halogenated disinfection byproducts (HDBPs). Because HDBPs are ubiquitous in chlorine-disinfected drinking water and have adverse human health implications, their concentrations are regulated in potable water supplies. Less is known about the formation and occurrence of HDBPs in disinfected WWTF effluents that are discharged to surface waters and become part of the de facto wastewater reuse cycle. This study investigated HDBPs in the urban water cycle from the stream source of the chlorinated municipal tap water that comprises the WWTF inflow, to the final WWTF effluent disinfection process before discharge back to the stream. The impact of conversion from chlorine-gas to low-pressure ultraviolet light (UV) disinfection at a full-scale (68,000 m(3) d(-1) design flow) WWTF on HDBP concentrations in the final effluent was assessed, as was transport and attenuation in the receiving stream. Nutrients and trace elements (boron, copper, and uranium) were used to characterize the different urban source waters, and indicated that the pre-upgrade and post-upgrade water chemistry was similar and insensitive to the disinfection process. Chlorinated tap water during the pre-upgrade and post-upgrade samplings contained 11 (mean total concentration=2.7 μg L(-1); n=5) and 10 HDBPs (mean total concentration=4.5 μg L(-1)), respectively. Under chlorine-gas disinfection conditions 13 HDBPs (mean total concentration=1.4 μg L(-1)) were detected in the WWTF effluent, whereas under UV disinfection conditions, only one HDBP was detected. The chlorinated WWTF effluent had greater relative proportions of nitrogenous, brominated, and iodinated HDBPs than the chlorinated tap water. Conversion of the WWTF to UV disinfection reduced the loading of HDBPs to the receiving stream by >90%. Copyright © 2015. Published by Elsevier B.V.

Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 6: Closed-cycle gas turbine systems. [energy conversion efficiency in electric power plants

NASA Technical Reports Server (NTRS)

Amos, D. J.; Fentress, W. K.; Stahl, W. F.

1976-01-01

Both recuperated and bottomed closed cycle gas turbine systems in electric power plants were studied. All systems used a pressurizing gas turbine coupled with a pressurized furnace to heat the helium for the closed cycle gas turbine. Steam and organic vapors are used as Rankine bottoming fluids. Although plant efficiencies of over 40% are calculated for some plants, the resultant cost of electricity was found to be 8.75 mills/MJ (31.5 mills/kWh). These plants do not appear practical for coal or oil fired plants.

43 CFR 3140.4 - Conversion.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Conversion. 3140.4 Section 3140.4 Public... OF THE INTERIOR MINERALS MANAGEMENT (3000) LEASING IN SPECIAL TAR SAND AREAS Conversion of Existing Oil and Gas Leases and Valid Claims Based on Mineral Locations § 3140.4 Conversion. ...

Entanglement of light-shift compensated atomic spin waves with telecom light.

PubMed

Dudin, Y O; Radnaev, A G; Zhao, R; Blumoff, J Z; Kennedy, T A B; Kuzmich, A

2010-12-31

Entanglement of a 795 nm light polarization qubit and an atomic Rb spin-wave qubit for a storage time of 0.1 s is observed by measuring the violation of Bell's inequality (S=2.65±0.12). Long qubit storage times are achieved by pinning the spin wave in a 1064 nm wavelength optical lattice, with a magic-valued magnetic field superposed to eliminate lattice-induced dephasing. Four-wave mixing in a cold Rb gas is employed to perform light qubit conversion between near infrared (795 nm) and telecom (1367 nm) wavelengths, and after propagation in a telecom fiber, to invert the conversion process. Observed Bell inequality violation (S=2.66±0.09), at 10 ms storage, confirms preservation of memory-light entanglement through the two stages of light qubit frequency conversion.

Achieving Simultaneous CO2 and H2 S Conversion via a Coupled Solar-Driven Electrochemical Approach on Non-Precious-Metal Catalysts.

PubMed

Ma, Weiguang; Wang, Hong; Yu, Wei; Wang, Xiaomei; Xu, Zhiqiang; Zong, Xu; Li, Can

2018-03-19

Carbon dioxide (CO 2 ) and hydrogen sulfide (H 2 S) are generally concomitant with methane (CH 4 ) in natural gas and traditionally deemed useless or even harmful. Developing strategies that can simultaneously convert both CO 2 and H 2 S into value-added products is attractive; however it has not received enough attention. A solar-driven electrochemical process is demonstrated using graphene-encapsulated zinc oxide catalyst for CO 2 reduction and graphene catalyst for H 2 S oxidation mediated by EDTA-Fe 2+ /EDTA-Fe 3+ redox couples. The as-prepared solar-driven electrochemical system can realize the simultaneous conversion of CO 2 and H 2 S into carbon monoxide and elemental sulfur at near neutral conditions with high stability and selectivity. This conceptually provides an alternative avenue for the purification of natural gas with added economic and environmental benefits. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Carbon dioxide splitting in a dielectric barrier discharge plasma: a combined experimental and computational study.

PubMed

Aerts, Robby; Somers, Wesley; Bogaerts, Annemie

2015-02-01

Plasma technology is gaining increasing interest for the splitting of CO2 into CO and O2 . We have performed experiments to study this process in a dielectric barrier discharge (DBD) plasma with a wide range of parameters. The frequency and dielectric material did not affect the CO2 conversion and energy efficiency, but the discharge gap can have a considerable effect. The specific energy input has the most important effect on the CO2 conversion and energy efficiency. We have also presented a plasma chemistry model for CO2 splitting, which shows reasonable agreement with the experimental conversion and energy efficiency. This model is used to elucidate the critical reactions that are mostly responsible for the CO2 conversion. Finally, we have compared our results with other CO2 splitting techniques and we identified the limitations as well as the benefits and future possibilities in terms of modifications of DBD plasmas for greenhouse gas conversion in general. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Apparatus and method for improving electrostatic precipitator performance by plasma reactor conversion of SO.sub.2 to SO.sub.3

DOEpatents

Huang, Hann-Sheng; Gorski, Anthony J.

1999-01-01

An apparatus and process that utilize a low temperature nonequilibrium plasma reactor, for improving the particulate removal efficiency of an electrostatic precipitator (ESP) are disclosed. A portion of the flue gas, that contains a low level of SO.sub.2 O.sub.2 H.sub.2 O, and particulate matter, is passed through a low temperature plasma reactor, which defines a plasma volume, thereby oxidizing a portion of the SO.sub.2 present in the flue gas into SO.sub.3. An SO.sub.2 rich flue gas is thereby generated. The SO.sub.3 rich flue gas is then returned to the primary flow of the flue gas in the exhaust treatment system prior to the ESP. This allows the SO.sub.3 to react with water to form H.sub.2 SO.sub.4 that is in turn is absorbed by fly ash in the gas stream in order to improve the removal efficiency of the EPS.

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.

Coal conversion products Industrial applications

NASA Technical Reports Server (NTRS)

Warren, D.; Dunkin, J.

1980-01-01

The synfuels economic evaluation model was utilized to analyze cost and product economics of the TVA coal conversion facilities. It is concluded that; (1) moderate yearly future escalations ( 6%) in current natural gas prices will result in medium-Btu gas becoming competitive with natural gas at the plant boundary; (2) utilizing DRI price projections, the alternate synfuel products, except for electricity, will be competitive with their counterparts; (3) central site fuel cell generation of electricity, utilizing MBG, is economically less attractive than the other synthetic fuels, given projected price rises in electricity produced by other means; and (4) because of estimated northern Alabama synfuels market demands, existing conventional fuels, infrastructure and industrial synfuels retrofit problems, a diversity of transportable synfuels products should be produced by the conversion facility.

43 CFR 3140.3-1 - Conversion applications.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Conversion applications. 3140.3-1 Section 3140.3-1 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND... Conversion of Existing Oil and Gas Leases and Valid Claims Based on Mineral Locations § 3140.3-1 Conversion...

Low Quality Natural Gas Sulfur Removal and Recovery CNG Claus Sulfur Recovery Process

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

Klint, V.W.; Dale, P.R.; Stephenson, C.

1997-10-01

Increased use of natural gas (methane) in the domestic energy market will force the development of large non-producing gas reserves now considered to be low quality. Large reserves of low quality natural gas (LQNG) contaminated with hydrogen sulfide (H{sub 2}S), carbon dioxide (CO{sub 2}) and nitrogen (N) are available but not suitable for treatment using current conventional gas treating methods due to economic and environmental constraints. A group of three technologies have been integrated to allow for processing of these LQNG reserves; the Controlled Freeze Zone (CFZ) process for hydrocarbon / acid gas separation; the Triple Point Crystallizer (TPC) processmore » for H{sub 2}S / C0{sub 2} separation and the CNG Claus process for recovery of elemental sulfur from H{sub 2}S. The combined CFZ/TPC/CNG Claus group of processes is one program aimed at developing an alternative gas treating technology which is both economically and environmentally suitable for developing these low quality natural gas reserves. The CFZ/TPC/CNG Claus process is capable of treating low quality natural gas containing >10% C0{sub 2} and measurable levels of H{sub 2}S and N{sub 2} to pipeline specifications. The integrated CFZ / CNG Claus Process or the stand-alone CNG Claus Process has a number of attractive features for treating LQNG. The processes are capable of treating raw gas with a variety of trace contaminant components. The processes can also accommodate large changes in raw gas composition and flow rates. The combined processes are capable of achieving virtually undetectable levels of H{sub 2}S and significantly less than 2% CO in the product methane. The separation processes operate at pressure and deliver a high pressure (ca. 100 psia) acid gas (H{sub 2}S) stream for processing in the CNG Claus unit. This allows for substantial reductions in plant vessel size as compared to conventional Claus / Tail gas treating technologies. A close integration of the components of the CNG Claus process also allow for use of the methane/H{sub 2}S separation unit as a Claus tail gas treating unit by recycling the CNG Claus tail gas stream. This allows for virtually 100 percent sulfur recovery efficiency (virtually zero SO{sub 2} emissions) by recycling the sulfur laden tail gas to extinction. The use of the tail gas recycle scheme also deemphasizes the conventional requirement in Claus units to have high unit conversion efficiency and thereby make the operation much less affected by process upsets and feed gas composition changes. The development of these technologies has been ongoing for many years and both the CFZ and the TPC processes have been demonstrated at large pilot plant scales. On the other hand, prior to this project, the CNG Claus process had not been proven at any scale. Therefore, the primary objective of this portion of the program was to design, build and operate a pilot scale CNG Claus unit and demonstrate the required fundamental reaction chemistry and also demonstrate the viability of a reasonably sized working unit.« less

Environmental Impact of Natural Gas Hydrate Production

NASA Astrophysics Data System (ADS)

Max, M. D.; Johnson, A. H.

2017-12-01

Unmet conventional energy demand is encouraging a number of deep energy importing nations closer to production of their potentially very large Natural Gas Hydrate (NGH) resources. As methane and other natural gases are potent greenhouse gases, concerns exist about the possible environmental risks associated NGH development. Accidental of natural gas would have environmental consequences. However, the special characteristics of NGH and production models indicate a very low environmental risk from the reservoir to the deepwater wellhead that is much lower than for conventional deepwater gas. NGH is naturally stable in its solid form in the reservoir and shutting in the gas can be achieved by stopping NGH conversion and gas production in the reservoir. Rapid shut down results in re-crystallization of gas and stabilization of the reservoir through NGH reformation. In addition, new options for innovative technologies have the potential to allow safe development of NGH at a fraction of the current estimated cost. Gas produced from NGH is about the same as processed conventional gas, although almost certainly more pure. Leakage of gas during transport is not a production issue. Gas transport leakage is a matter for best practices regulation that is rigorously enforced.

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

Lobo, R.; Revah, S.; Viveros-Garcia, T.

An analysis of the local processes occurring in a trickle-bed bioreactor (TBB) with a first-order bioreaction shows that the identification of the TBB operating regime requires knowledge of the substrate concentration in the liquid phase. If the substrate liquid concentration is close to 0, the rate-controlling step is mass transfer at the gas-liquid interface; when it is close to the value in equilibrium with the gas phase, the controlling step is the phenomena occurring in the biofilm, CS{sub 2} removal rate data obtained in a TBB with a Thiobacilii consortia biofilm are analyzed to obtain the mass transfer and kineticmore » parameters, and to show that the bioreactor operates in a regime mainly controlled by mass transfer. A TBB model with two experimentally determined parameters is developed and used to show how the bioreactor size depends on the rate-limiting step, the absorption factor, the substrate fractional conversion, and on the gas and liquid contact pattern. Under certain conditions, the TBB size is independent of the flowing phases` contact pattern. The model effectively describes substrate gas and liquid concentration data for mass transfer and biodegradation rate controlled processes.« less

Full Waveform Modelling for Subsurface Characterization with Converted-Wave Seismic Reflection

NASA Astrophysics Data System (ADS)

Triyoso, Wahyu; Oktariena, Madaniya; Sinaga, Edycakra; Syaifuddin, Firman

2017-04-01

While a large number of reservoirs have been explored using P-waves seismic data, P-wave seismic survey ceases to provide adequate result in seismically and geologically challenging areas, like gas cloud, shallow drilling hazards, strong multiples, highly fractured, anisotropy. Most of these reservoir problems can be addressed using P and PS seismic data combination. Multicomponent seismic survey records both P-wave and S-wave unlike conventional survey that only records compressional P-wave. Under certain conditions, conventional energy source can be used to record P and PS data using the fact that compressional wave energy partly converts into shear waves at the reflector. Shear component can be recorded using down going P-wave and upcoming S-wave by placing a horizontal component geophone on the ocean floor. A synthetic model is created based on real data to analyze the effect of gas cloud existence to PP and PS wave reflections which has a similar characteristic to Sub-Volcanic imaging. The challenge within the multicomponent seismic is the different travel time between P-wave and S-wave, therefore the converted-wave seismic data should be processed with different approach. This research will provide a method to determine an optimum converted point known as Common Conversion Point (CCP) that can solve the Asymmetrical Conversion Point of PS data. The value of γ (Vp/Vs) is essential to estimate the right CCP that will be used in converted-wave seismic processing. This research will also continue to the advanced processing method of converted-wave seismic by applying Joint Inversion to PP&PS seismic. Joint Inversion is a simultaneous model-based inversion that estimates the P&S-wave impedance which are consistent with the PP&PS amplitude data. The result reveals a more complex structure mirrored in PS data below the gas cloud area. Through estimated γ section resulted from Joint Inversion, we receive a better imaging improvement below gas cloud area tribute to the converted-wave seismic as additional constrain.

Energy from gasification of solid wastes.

PubMed

Belgiorno, V; De Feo, G; Della Rocca, C; Napoli, R M A

2003-01-01

Gasification technology is by no means new: in the 1850s, most of the city of London was illuminated by "town gas" produced from the gasification of coal. Nowadays, gasification is the main technology for biomass conversion to energy and an attractive alternative for the thermal treatment of solid waste. The number of different uses of gas shows the flexibility of gasification and therefore allows it to be integrated with several industrial processes, as well as power generation systems. The use of a waste-biomass energy production system in a rural community is very interesting too. This paper describes the current state of gasification technology, energy recovery systems, pre-treatments and prospective in syngas use with particular attention to the different process cycles and environmental impacts of solid wastes gasification.

Effect of Ce2O3, La2O3 and ZnO additives on the oxygenates conversion into liquid hydrocarbons

NASA Astrophysics Data System (ADS)

Kachalov, V. V.; Lavrenov, V. A.; Lishchiner, I. I.; Malova, O. V.; Tarasov, A. L.; Zaichenko, V. M.

2018-01-01

A selective modifying effect of cerium, magnesium and zinc oxide additives on the activity and the selectivity of a pentasil group zeolite catalyst in the reaction of conversion of oxygenates (methanol and dimethyl ether) to liquid hydrocarbons was found. It was found that zinc oxide contributes to the stable operation of the zeolite catalyst in the conversion of oxygenates in the synthesis gas stream and leads to the production of gasolines with low durene content (not more than 6.1 wt%). The obtained results demonstrate the rationale for producing hydrocarbons from synthesis gas without the stage of oxygenate separation with their subsequent conversion to synthetic gasoline.

Pyrolysis characteristics and kinetics of oil-based drilling cuttings in shale gas developing

NASA Astrophysics Data System (ADS)

Huang, Chuan; Li, Tong; Xu, Tengtun; Zeng, Yunmin; Song, Xue

2018-03-01

In this paper, the thermal behavior of waste oil-based drilling cuttings (from shale gas fields in Chongqing) was examined at different heating rates ranging from 5 to 15 °C min-1 in inert atmosphere using a sync analyzer of thermogravimetry (TG) and differential scanning calorimetry (DSC). Four methods were used to analyze the distributions and variations of kinetics parameter (active energy (E) and frequency gene (A)): Coats-Redfern and other three iso-conversion rate methods (Flynn-Wall-Ozawa, Vyazovkin and Friedman). The experimental results indicated that the process consists of three steps, i.e., water evaporation, volatilization of light oil component and heavy oil cracking. TG curves moved toward higher temperature zone caused by thermal hysteresis with the increase of temperature rising rate. For volatilization of lightweight components, the E calculated by three iso-conversion rate methods changed a little with conversion, and had almost the same results as the CR method (14.39˜20.08 kJ.mol-1). For reactions of heavy oil cracking with mixed mechanism, corresponding E rose gradually with the increase of reaction time. The CR method shows nonlinear trends and the reaction models and kinetic parameters cannot be extracted from CR curves. The results by three iso-conversion methods showed that apparent activation energy was given as 155.74˜561.10 kJ.mol-1, 141.06˜524.96 kJ.mol-1 and 74.37˜605.10 kJ.mol-1, respectively.

Method of producing a colloidal fuel from coal and a heavy petroleum fraction

DOEpatents

Longanbach, James R.

1983-08-09

A method is provided for combining coal as a colloidal suspension within a heavy petroleum fraction. The coal is broken to a medium particle size and is formed into a slurry with a heavy petroleum fraction such as a decanted oil having a boiling point of about 300.degree.-550.degree. C. The slurry is heated to a temperature of 400.degree.-500.degree. C. for a limited time of only about 1-5 minutes before cooling to a temperature of less than 300.degree. C. During this limited contact time at elevated temperature the slurry can be contacted with hydrogen gas to promote conversion. The liquid phase containing dispersed coal solids is filtered from the residual solids and recovered for use as a fuel or feed stock for other processes. The residual solids containing some carbonaceous material are further processed to provide hydrogen gas and heat for use as required in this process.

Industrial conversion costs from oil and gas to alternative fuels

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

Askari, H.; Reichert, A.T.

1977-01-01

From a national standpoint, many questions can be raised on conversion -- whether mandatory or through taxation. 1) Why is it necessary to intervene in the market since price increases will act to allocate available fuels. The desire to reduce dependence on imported oil and gas may be an overriding constraint -- an unproven proposition; some believe that price increases would not have a significant positive impact on output -- a position without a great deal of economic or geological foundation; and the President, for obvious reasons, did not want to force households into conversion nor did he want tomore » propose deregulation which, in the short run, may increase prices directly to consumers but it would be politically more palatable to pass on energy price increase through industry; though astute politically, the economic merit of such a decision is very questionable. 2) Is the cutback of oil and gas consumption being targeted into the least critical area of national need, namely industry. 3) From the national perspective, is conversion desirable as compared to continued dependence on foreign oil for existing plants, with non-petroleum fuel sources for new plants and new residential dwellings. If conversion costs are prohibitive, then it may be ruled out. If conversion costs are low but the real cost of using coal or electricity far exceeds the economic risk of OPEC price increases or embargoes, then again conversion may be ruled out. In short, even if conversion costs are low, it is far from obvious that conversion is desirable. In this paper, the question of conversion cost and its regional implications is examined in detail.« less

Relevance of deep-subsurface microbiology for underground gas storage and geothermal energy production.

PubMed

Gniese, Claudia; Bombach, Petra; Rakoczy, Jana; Hoth, Nils; Schlömann, Michael; Richnow, Hans-Hermann; Krüger, Martin

2014-01-01

This chapter gives the reader an introduction into the microbiology of deep geological systems with a special focus on potential geobiotechnological applications and respective risk assessments. It has been known for decades that microbial activity is responsible for the degradation or conversion of hydrocarbons in oil, gas, and coal reservoirs. These processes occur in the absence of oxygen, a typical characteristic of such deep ecosystems. The understanding of the responsible microbial processes and their environmental regulation is not only of great scientific interest. It also has substantial economic and social relevance, inasmuch as these processes directly or indirectly affect the quantity and quality of the stored oil or gas. As outlined in the following chapter, in addition to the conventional hydrocarbons, new interest in such deep subsurface systems is rising for different technological developments. These are introduced together with related geomicrobiological topics. The capture and long-termed storage of large amounts of carbon dioxide, carbon capture and storage (CCS), for example, in depleted oil and gas reservoirs, is considered to be an important options to mitigate greenhouse gas emissions and global warming. On the other hand, the increasing contribution of energy from natural and renewable sources, such as wind, solar, geothermal energy, or biogas production leads to an increasing interest in underground storage of renewable energies. Energy carriers, that is, biogas, methane, or hydrogen, are often produced in a nonconstant manner and renewable energy may be produced at some distance from the place where it is needed. Therefore, storing the energy after its conversion to methane or hydrogen in porous reservoirs or salt caverns is extensively discussed. All these developments create new research fields and challenges for microbiologists and geobiotechnologists. As a basis for respective future work, we introduce the three major topics, that is, CCS, underground storage of gases from renewable energy production, and the production of geothermal energy, and summarize the current stat of knowledge about related geomicrobiological and geobiotechnological aspects in this chapter. Finally, recommendations are made for future research.

Water demands for expanding energy development

USGS Publications Warehouse

Davis, G.H.; Wood, Leonard A.

1974-01-01

Water is used in producing energy for mining and reclamation of mined lands, onsite processing, transportation, refining, and conversion of fuels to other forms of energy. In the East, South, Midwest, and along the seacoasts, most water problems are related to pollution rather than to water supply. West of about the 100th meridian, however, runoff is generally less than potential diversions, and energy industries must compete with other water users. Water demands for extraction of coal, oil shale, uranium, and oil and gas are modest, although large quantities of water are used in secondary recovery operations for oil. The only significant use of water for energy transportation, aside from in-stream navigation use, is for slurry lines. Substantial quantities of water are required in the retorting and the disposal of spent oil shale. The conversion of coal to synthetic gas or oil or to electric power and the generation of electric power with nuclear energy require large quantities of water, mostly for cooling. Withdrawals for cooling of thermal-electric plants is by far the largest category of water use in energy industry, totaling about 170 billion gallons (644 million m3) per day in 1970. Water availability will dictate the location and design of energy-conversion facilities, especially in water deficient areas of the West.

Climate Impact and Economic Feasibility of Solar Thermochemical Jet Fuel Production.

PubMed

Falter, Christoph; Batteiger, Valentin; Sizmann, Andreas

2016-01-05

Solar thermochemistry presents a promising option for the efficient conversion of H2O and CO2 into liquid hydrocarbon fuels using concentrated solar energy. To explore the potential of this fuel production pathway, the climate impact and economic performance are analyzed. Key drivers for the economic and ecological performance are thermochemical energy conversion efficiency, the level of solar irradiation, operation and maintenance, and the initial investment in the fuel production plant. For the baseline case of a solar tower concentrator with CO2 capture from air, jet fuel production costs of 2.23 €/L and life cycle greenhouse gas (LC GHG) emissions of 0.49 kgCO2-equiv/L are estimated. Capturing CO2 from a natural gas combined cycle power plant instead of the air reduces the production costs by 15% but leads to LC GHG emissions higher than that of conventional jet fuel. Favorable assumptions for all involved process steps (30% thermochemical energy conversion efficiency, 3000 kWh/(m(2) a) solar irradiation, low CO2 and heliostat costs) result in jet fuel production costs of 1.28 €/L at LC GHG emissions close to zero. Even lower production costs may be achieved if the commercial value of oxygen as a byproduct is considered.

Algal Energy Conversion and Capture

NASA Astrophysics Data System (ADS)

Hazendonk, P.

2015-12-01

We address the potential for energy conversions and capture for: energy generation; reduction in energy use; reduction in greenhouse gas emissions; remediation of water and air pollution; protection and enhancement of soil fertility. These processes have the potential to sequester carbon at scales that may have global impact. Energy conversion and capture strategies evaluate energy use and production from agriculture, urban areas and industries, and apply existing and emerging technologies to reduce and recapture energy embedded in waste products. The basis of biocrude production from Micro-algal feedstocks: 1) The nutrients from the liquid fraction of waste streams are concentrated and fed into photo bioreactors (essentially large vessels in which microalgae are grown) along with CO2 from flue gasses from down stream processes. 2) The algae are processed to remove high value products such as proteins and beta-carotenes. The advantage of algae feedstocks is the high biomass productivity is 30-50 times that of land based crops and the remaining biomass contains minimal components that are difficult to convert to biocrude. 3) The remaining biomass undergoes hydrothermal liquefaction to produces biocrude and biochar. The flue gasses of this process can be used to produce electricity (fuel cell) and subsequently fed back into the photobioreactor. The thermal energy required for this process is small, hence readily obtained from solar-thermal sources, and furthermore no drying or preprocessing is required keeping the energy overhead extremely small. 4) The biocrude can be upgraded and refined as conventional crude oil, creating a range of liquid fuels. In principle this process can be applied on the farm scale to the municipal scale. Overall, our primary food production is too dependent on fossil fuels. Energy conversion and capture can make food production sustainable.

Gasification of refinery sludge in an updraft reactor for syngas production

NASA Astrophysics Data System (ADS)

Ahmed, Reem; Sinnathambi, Chandra M.; Eldmerdash, Usama

2014-10-01

The study probes into the investigation on gasification of dry refinery sludge. The details of the study includes; influence of operation time, oxidation temperature and equivalence ratios on carbon gas conversion rate, gasification efficiency, heating value and fuel gas yield are presented. The results show that, the oxidation temperature increased sharply up to 858°C as the operating time increased up to 36 min then bridging occurred at 39 min which cause drop in reaction temperature up to 819 °C. This bridging was found to affect also the syngas compositions, meanwhile as the temperature decreased the CO, H2, CH4 compositions are also found to be decreases. Higher temperature catalyzed the reduction reaction (CO2+ C = 450 2CO ), and accelerated the carbon conversion and gasification efficiencies, resulted in more solid fuel is converted to a high heating value gas fuel. The equivalence ratio of 0.195 was found to be the optimum value for carbon conversion and cold gas efficiencies, high heating value of gas, and fuel gas yield to reach their maximum values of 96.1 % and 53.7 %, 5.42 MJ Nm-3 of, and 2.5 Nm3 kg-1 respectively.

Thermal conversion of municipal solid waste via hydrothermal carbonization: comparison of carbonization products to products from current waste management techniques.

PubMed

Lu, Xiaowei; Jordan, Beth; Berge, Nicole D

2012-07-01

Hydrothermal carbonization (HTC) is a novel thermal conversion process that may be a viable means for managing solid waste streams while minimizing greenhouse gas production and producing residual material with intrinsic value. HTC is a wet, relatively low temperature (180-350 °C) thermal conversion process that has been shown to convert biomass to a carbonaceous residue referred to as hydrochar. Results from batch experiments indicate HTC of representative waste materials is feasible, and results in the majority of carbon (45-75% of the initially present carbon) remaining within the hydrochar. Gas production during the batch experiments suggests that longer reaction periods may be desirable to maximize the production of energy-favorable products. If using the hydrochar for applications in which the carbon will remain stored, results suggest that the gaseous products from HTC result in fewer g CO(2)-equivalent emissions than the gases associated with landfilling, composting, and incineration. When considering the use of hydrochar as a solid fuel, more energy can be derived from the hydrochar than from the gases resulting from waste degradation during landfilling and anaerobic digestion, and from incineration of food waste. Carbon emissions resulting from the use of the hydrochar as a fuel source are smaller than those associated with incineration, suggesting HTC may serve as an environmentally beneficial alternative to incineration. The type and extent of environmental benefits derived from HTC will be dependent on hydrochar use/the purpose for HTC (e.g., energy generation or carbon storage). Copyright © 2012 Elsevier Ltd. All rights reserved.

Review of Biojet Fuel Conversion Technologies

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

Wang, Wei-Cheng; Tao, Ling; Markham, Jennifer

Biomass-derived jet (biojet) fuel has become a key element in the aviation industry’s strategy to reduce operating costs and environmental impacts. Researchers from the oil-refining industry, the aviation industry, government, biofuel companies, agricultural organizations, and academia are working toward developing commercially viable and sustainable processes that produce long-lasting renewable jet fuels with low production costs and low greenhouse gas emissions. Additionally, jet fuels must meet ASTM International specifications and potentially be a 100% drop-in replacement for the current petroleum jet fuel. The combustion characteristics and engine tests demonstrate the benefits of running the aviation gas turbine with biojet fuels. Inmore » this study, the current technologies for producing renewable jet fuels, categorized by alcohols-to-jet, oil-to-jet, syngas-to-jet, and sugar-to-jet pathways, are reviewed. The main challenges for each technology pathway, including feedstock availability, conceptual process design, process economics, life-cycle assessment of greenhouse gas emissions, and commercial readiness, are discussed. Although the feedstock price and availability and energy intensity of the process are significant barriers, biomass-derived jet fuel has the potential to replace a significant portion of conventional jet fuel required to meet commercial and military demand.« less

Fast molecular shocks. I - Reformation of molecules behind a dissociative shock

NASA Technical Reports Server (NTRS)

Neufeld, David A.; Dalgarno, A.

1989-01-01

The physical and chemical processes that operate in the cooling gas behind a fast, dissociative, single-fluid shock propagating in a dense interstellar cloud are discussed. The treatment extends previous theoretical work on fast molecular shocks by including the effects of the conversion of Ly-alpha photons into radiation of the two-photon continuum and into H2 Lyman band emission lines, the effects of CO photodissociation following line absorption, and the formation and destruction of molecules containing the elements nitrogen, silicon, and sulphur, and of the complex hydrocarbons. Abundance profiles for the molecular species of interest are presented. After molecular hydrogen begins to reform, by means of gas phase and grain surface processes, the neutral species OH, H2O, O2, CO, CN, HCN, N2, NO, SO, and SiO reach substantial abundances. The molecular ions HeH(+), OH(+), SO(+), CH(+), H2(+), and H3(+), are produced while the gas is still hot and partially ionized. Emissions from them provide a possible diagnostic probe of fast molecular shocks.

Sustainable Transportation Fuels from Natural Gas (H{sub 2}), Coal and Biomass

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

Huffman, Gerald

2012-12-31

This research program is focused primarily on the conversion of coal, natural gas (i.e., methane), and biomass to liquid fuels by Fischer-Tropsch synthesis (FTS), with minimum production of carbon dioxide. A complementary topic also under investigation is the development of novel processes for the production of hydrogen with very low to zero production of CO{sub 2}. This is in response to the nation's urgent need for a secure and environmentally friendly domestic source of liquid fuels. The carbon neutrality of biomass is beneficial in meeting this goal. Several additional novel approaches to limiting carbon dioxide emissions are also being explored.

Efficient and Selective Electrochemical and Photoelectrochemical Reduction of 5-Hydroxymethylfurfural to 2,5-Bis(hydroxymethyl)furan using Water as the Hydrogen Source

DOE PAGES

Roylance, John J.; Kim, Tae Woo; Choi, Kyoung-Shin

2016-02-17

Reductive biomass conversion has been conventionally conducted using H 2 gas under high-temperature and-pressure conditions. Here, efficient electrochemical reduction of 5-hydroxymethylfurfural (HMF), a key intermediate for biomass conversion, to 2,5-bis(hydroxymethyl)furan (BHMF), an important monomer for industrial processes, was demonstrated using Ag catalytic electrodes. This process uses water as the hydrogen source under ambient conditions and eliminates the need to generate and consume H 2 for hydrogenation, providing a practical and efficient route for BHMF production. By systematic investigation of HMF reduction on the Ag electrode surface, BHMF production was achieved with the Faradaic efficiency and selectivity nearing 100%, and plausiblemore » reduction mechanisms were also elucidated. Furthermore, construction of a photoelectrochemical cell (PEC) composed of an n-type BiVO 4 semiconductor anode, which uses photogenerated holes for water oxidation, and a catalytic Ag cathode, which uses photoexcited electrons from BiVO 4 for the reduction of HMF to BHMF, was demonstrated to utilize solar energy to significantly decrease the external voltage necessary for HMF reduction. This shows the possibility of coupling electrochemical HMF reduction and solar energy conversion, which can provide more efficient and environmentally benign routes for reductive biomass conversion.« 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.

The effects of salt, particle and pore size on the process of carbon dioxide hydrate formation: A critical review

NASA Astrophysics Data System (ADS)

Ghaedi, Hosein; Ayoub, Muhammad; Bhat, A. H.; Mahmood, Syed Mohammad; Akbari, Saeed; Murshid, Ghulam

2016-11-01

Hydration is an alternative method for CO2 capture. In doing so, some researchers use porous media on an experimental scale. This paper tries to gather the researches on the formation of CO2 hydrate in different types of porous media such as silica sand, quartz sand, Toyoura, pumice, and fire hardened red clay. This review has attempted to examine the effects of salt and particle sizes as two major factors on the induction time, water to hydrate conversion, gas uptake (or gas consumption), and the rate of CO2 hydrate formation. By performing a critical assessment of previous research works, it was observed that the figure for the gas uptake (or gas consumption) and water to hydrate conversion in porous media was decreased by increasing the particle size provided that the pore size was constant. Although, salt can play a role in hydrate formation as the thermodynamic inhibitor, the results show that salt can be regarded as the kinetic growth inhibitor and kinetic promoter. Because of the fact that the gas uptake in seawater is lower than pure water at the end of experiment, the salt can act as a kinetic growth inhibitor. However, since gas uptake (after the nucleation period and for a short period) and the initial rate of hydrate formation in saline water were more than that of pure water, salt can play a promoter role in the kinetic reaction, too. Besides these, in the case of pure water and within a certain particle size, the amount of the hydrate formation rate has been seen to be greater in smaller particles (provided that the pore size is constant), however this has not been observed for seawater.

Copper indium gallium selenide (CIGS) photovoltaic devices made using multistep selenization of nanocrystal films.

PubMed

Harvey, Taylor B; Mori, Isao; Stolle, C Jackson; Bogart, Timothy D; Ostrowski, David P; Glaz, Micah S; Du, Jiang; Pernik, Douglas R; Akhavan, Vahid A; Kesrouani, Hady; Vanden Bout, David A; Korgel, Brian A

2013-09-25

The power conversion efficiency of photovoltaic devices made with ink-deposited Cu(InxGa1-x)Se2 (CIGS) nanocrystal layers can be enhanced by sintering the nanocrystals with a high temperature selenization process. This process, however, can be challenging to control. Here, we report that ink deposition followed by annealing under inert gas and then selenization can provide better control over CIGS nanocrystal sintering and yield generally improved device efficiency. Annealing under argon at 525 °C removes organic ligands and diffuses sodium from the underlying soda lime glass into the Mo back contact to improve the rate and quality of nanocrystal sintering during selenization at 500 °C. Shorter selenization time alleviates excessive MoSe2 formation at the Mo back contact that leads to film delamination, which in turn enables multiple cycles of nanocrystal deposition and selenization to create thicker, more uniform absorber films. Devices with power conversion efficiency greater than 7% are fabricated using the multiple step nanocrystal deposition and sintering process.

Catalytic conversion of light alkanes, Phase 3. Topical report, January 1990--December 1992

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

NONE

The mission of this work is to devise a new catalyst which can be used in the first simple, economic process to convert the light alkanes in natural gas to an alcohol-rich oxygenated product which can either be used as an environmentally friendly, high-performance liquid fuel, or a precursor to a liquid hydrocarbon transportation fuel. The authors have entered the proof-of-concept stage for converting isobutane to tert butyl alcohol in a practical process and are preparing to enter proof-of-concept of a propane to isopropyl alcohol process in the near future. Methane and ethane are more refractory and thus more difficultmore » to oxidize than the C{sub 3} and C{sub 4} hydrocarbons. Nonetheless, advances made in this area indicate that further research progress could achieve the goal of their direct conversion to alcohols. Progress in Phase 3 catalytic vapor phase methane and ethane oxidation over metals in regular oxidic lattices are the subject of this topical report.« less

Environmental Restoration - Expedient Methods and Technologies: A User Guide with Case Studies

DTIC Science & Technology

1998-03-01

benzene, high fructose corn syrup , raw molasses, butane gas, sodium benzoate, or acetate. Enhanced anaerobic biodegradation of jet fuels in ground water...appendix discusses technology applications that are deemed impractical because of high cost, difficulty of use, or other factors. Also included is a...conversations with knowledgeable 1 Technologically sophisticated processes are not addressed in this study because of high cost, which includes the engineering

Relative Sustainability of Natural Gas Assisted High-Octane Gasoline Blendstock Production from Biomass

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

Tan, Eric C; Zhang, Yi Min; Cai, Hao

Biomass-derived hydrocarbon fuel technologies are being developed and pursued for better economy, environment, and society benefits underpinning the sustainability of transportation energy. Increasing availability and affordability of natural gas (NG) in the US can play an important role in assisting renewable fuel technology development, primarily in terms of economic feasibility. When a biorefinery is co-processing NG with biomass, the current low cost of NG coupled with the higher NG carbon conversion efficiency potentially allow for cost competitiveness of the fuel while achieving a minimum GHG emission reduction of 50 percent or higher compared to petroleum fuel. This study evaluates themore » relative sustainability of the production of high-octane gasoline blendstock via indirect liquefaction (IDL) of biomass (and with NG co-feed) through methanol/dimethyl ether intermediates. The sustainability metrics considered in this study include minimum fuel selling price (MFSP), carbon conversion efficiency, life cycle GHG emissions, life cycle water consumption, fossil energy return on investment (EROI), GHG emission avoidance cost, and job creation. Co-processing NG can evidently improve the MFSP. Evaluation of the relative sustainability can shed light on the biomass-NG synergistic impacts and sustainability trade-offs associated with the IDL as high-octane gasoline blendstock production.« less

Canopy volume removal from oil and gas development activity in the upper Susquehanna River basin in Pennsylvania and New York (USA): An assessment using lidar data

USGS Publications Warehouse

Young, John A.; Maloney, Kelly O.; Slonecker, Terry; Milheim, Lesley E.; Siripoonsup, David

2018-01-01

Oil and gas development is changing the landscape in many regions of the United States and globally. However, the nature, extent, and magnitude of landscape change and development, and precisely how this development compares to other ongoing land conversion (e.g. urban/sub-urban development, timber harvest) is not well understood. In this study, we examine land conversion from oil and gas infrastructure development in the upper Susquehanna River basin in Pennsylvania and New York, an area that has experienced much oil and gas development over the past 10 years. We quantified land conversion in terms of forest canopy geometric volume loss in contrast to previous studies that considered only areal impacts. For the first time in a study of this type, we use fine-scale lidar forest canopy geometric models to assess the volumetric change due to forest clearing from oil and gas development and contrast this land change to clear cut forest harvesting, and urban and suburban development. Results show that oil and gas infrastructure development removed a large volume of forest canopy from 2006 to 2013, and this removal spread over a large portion of the study area. Timber operations (clear cutting) on Pennsylvania State Forest lands removed a larger total volume of forest canopy during the same time period, but this canopy removal was concentrated in a smaller area. Results of our study point to the need to consider volumetric impacts of oil and gas development on ecosystems, and to place potential impacts in context with other ongoing land conversions.

Economic considerations in coverting from oil/gas firing to coal

NASA Technical Reports Server (NTRS)

Rau, J. G.

1978-01-01

Economic considerations involved in fuel conversion such as from oil and/or gas firing to coal are discussed including investments costs for new facilities and equipment (including air pollution control equipment), operation and maintenance costs, and purchased fuel costs. An analytical approach to assessing the cost effectiveness of fuel conversion in terms of the annual net cost of conversion, the equivalent annual number of barrels of oil saved, and the integral rate of return of the conversion investment is presented. Illustrative numerical examples are presented for typical utility boilers and industrial boiler facilities. A further consideration addressed deals with the impacts of these costs on the overall financial structure of the firm and the ability of the firm to raise the necessary investment captial.

Gas depletion through single gas bubble diffusive growth and its effect on subsequent bubbles

NASA Astrophysics Data System (ADS)

Moreno Soto, Alvaro; Prosperetti, Andrea; Lohse, Detlef; van der Meer, Devaraj; Physics of Fluid Group Collaboration; MCEC Netherlands CenterMultiscale Catalytic Energy Conversion Collaboration

2016-11-01

In weakly supersaturated mixtures, bubbles are known to grow quasi-statically as diffusion-driven mass transfer governs the process. In the final stage of the evolution, before detachment, there is an enhancement of mass transfer, which changes from diffusion to natural convection. Once the bubble detaches, it leaves behind a gas-depleted area. The diffusive mass transfer towards that region cannot compensate for the amount of gas which is taken away by the bubble. Consequently, the consecutive bubble will grow in an environment which contains less gas than for the previous one. This reduces the local supersaturation of the mixture around the nucleation site, leading to a reduced bubble growth rate. We present quantitative experimental data on this effect and the theoretical model for depletion during the bubble growth rate. This work was supported by the Netherlands Center for Multiscale Catalytic Energy Conversion (MCEC), an NWO Gravitation programme funded by the Ministry of Education, Culture and Science of the government of the Netherlands.

Energetic approach of biomass hydrolysis in supercritical water.

PubMed

Cantero, Danilo A; Vaquerizo, Luis; Mato, Fidel; Bermejo, M Dolores; Cocero, M José

2015-03-01

Cellulose hydrolysis can be performed in supercritical water with a high selectivity of soluble sugars. The process produces high-pressure steam that can be integrated, from an energy point of view, with the whole biomass treating process. This work investigates the integration of biomass hydrolysis reactors with commercial combined heat and power (CHP) schemes, with special attention to reactor outlet streams. The innovation developed in this work allows adequate energy integration possibilities for heating and compression by using high temperature of the flue gases and direct shaft work from the turbine. The integration of biomass hydrolysis with a CHP process allows the selective conversion of biomass into sugars with low heat requirements. Integrating these two processes, the CHP scheme yield is enhanced around 10% by injecting water in the gas turbine. Furthermore, the hydrolysis reactor can be held at 400°C and 23 MPa using only the gas turbine outlet streams. Copyright © 2014 Elsevier Ltd. All rights reserved.

Generalized formulation of free energy and application to photosynthesis

NASA Astrophysics Data System (ADS)

Zhang, Hwe Ik; Choi, M. Y.

2018-03-01

The origin of free energy on the earth is solar radiation. However, the amount of free energy it contains has seldom been investigated, because the free energy concept was believed to be inappropriate for a system of photons. Instead, the origin of free energy has been sought in the process of photosynthesis, imposing a limit of conversion given by the Carnot efficiency. Here we present a general formulation, capable of not only assessing accurately the available amount of free energy in the photon gas but also explaining the primary photosynthetic process more succinctly. In this formulation, the problem of "photosynthetic conversion of the internal energy of photons into the free energy of chlorophyll" is replaced by simple "free energy transduction" between the photons and chlorophyll. An analytic expression for the photosynthetic efficiency is derived and shown to deviate from the Carnot efficiency. Some predictions verifiable possibly by observation are also suggested.

Dye ingredients and energy conversion efficiency at natural dye sensitized solar cells

NASA Astrophysics Data System (ADS)

Özbay Karakuş, Mücella; Koca, İrfan; Er, Orhan; Çetin, Hidayet

2017-04-01

In this work, natural dyes extracted from the same genus but different species flowers were used as sensitizer in Dye Sensitized Solar Cell (DSSC). To clearly show dye ingredients effect on electrical characteristics, the same genus flowers were selected. The dye ingredients were analyzed by Gas Chromatography Mass Spectrometer (GC-MS). The dyes were modified by a procedure that includes refluxing in acetone. All results indicate a relationship between gallic acid quantity in dyes and solar cell efficiency. To gain further insight, the solar cell parameters were obtained by using the single-diode and double-diode models and they were compared to each other. It was observed that the applied process causes a decrease in series resistance. How the modification process and gallic acid affect energy conversion efficiency were argued in detail in the frame of results that were obtained from solar cell models.

Integration of Power to Methane in a waste water treatment plant - A feasibility study.

PubMed

Patterson, Tim; Savvas, Savvas; Chong, Alex; Law, Ian; Dinsdale, Richard; Esteves, Sandra

2017-12-01

The integration of a biomethanation system within a wastewater treatment plant for conversion of CO 2 and H 2 to CH 4 has been studied. Results indicate that the CO 2 could be utilised to produce an additional 13,420m 3 /day of CH 4 , equivalent to approximately 133,826kWh of energy. The whole conversion process including electrolysis was found to have an energetic efficiency of 66.2%. The currently un-optimised biomethanation element of the process had a parasitic load of 19.9% of produced energy and strategies to reduce this to <5% are identified. The system could provide strategic benefits such as integrated management of electricity and gas networks, energy storage and maximising the deployment and efficiency of renewable energy assets. However, no policy or financial frameworks exist to attribute value to these increasingly important functions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Air purification from a mixture VOCs in the pilot-scale trickle-bed bioreactor (TBB)

NASA Astrophysics Data System (ADS)

Sarzyński, Rafał; Gąszczak, Agnieszka; Janecki, Daniel; Bartelmus, Grażyna

2017-10-01

The efficiency of the air bio-purification from the mixture of two volatile organic compounds (styrene and p-xylene) was studied. The process was carried out in a pilot-scale trickle-bed bioreactor installation designed to purify ˜200 m3h-1 of the polluted air. The bioreactor operated at concurrent flow of gas and liquid (mineral salt solution) through packing (polypropylene Ralu rings) covered with a thin layer of microorganisms (bacterial consortium of Pseudomonas sp. E-022150 and Pseudomonas putida mt-2). The experiments, carried out for various values of a reactor load with pollutant, confirmed the great efficiency of the investigated process. At the tested bed load with pollution (inlet specific pollutant load was changed within the range of 41 - 84 gm-3 h -1), styrene conversion degree changed within the range of 80-87% and p-xylene conversion degree within the range of 42-48%.

Degradation of volatile organic compounds in the gas phase by heterogeneous photocatalysis with titanium dioxide/ultraviolet light.

PubMed

Rochetto, Ursula Luana; Tomaz, Edson

2015-07-01

This work presents an overview over heterogeneous photocatalysis performed in gas phase towards the degradation of o-xylene, n-hexane, n-octane, n-decane, methylcyclohexane and 2,2,4-trimethylpentane. The experimental set-up composed by a titanium plug flow reactor vessel contained a quartz tube with a 100 W UV lamp placed at center position from 1.7 cm to the quartz wall. A titanium dioxide film was immobilized on the internal walls of the reactor and used as catalyst. All measurements were taken after reaching steady state condition and evaluated at the inlet and outlet of the system. Conversion rates were studied in a wide range of residence times yielding to a 90% or above conversion as from 20 seconds of residence time. During experiments the temperature of reactor's wall was monitored and remained between 52 and 62 °C. Temperature influence over degradation rates was negligible once a control experiment performed at 15 °C did not modify outgoing results. Humidity effect was also evaluated showing an ideal working range of 10-80% with abrupt conversion decay outside the range. By varying inlet concentration between 60 and 110 ppmv the VOC degradation curves remained unchanged. Loss over catalytic activity was only observed for o-xylene after 30 minutes of reaction, the catalyst was reactivated with a solution of hydrogen peroxide and UV light followed by additional deposition of the catalytic layer. The kinetic study suggests a first order reaction rate. The study of effective and economically viable techniques on the treatment of volatile organic compounds (VOCs) has being highlighted as an important parameter on the environmental research. The heterogeneous photocatalysis in gas phase was proved to be an effective process for the degradation of the nonaromatic VOCs tested, yielding high conversion values for the optimized systems.

Well-to-wake analysis of ethanol-to-jet and sugar-to-jet pathways

DOE PAGES

Han, Jeongwoo; Tao, Ling; Wang, Michael

2017-01-24

To reduce the environmental impacts of the aviation sector as air traffic grows steadily, the aviation industry has paid increasing attention to bio-based alternative jet fuels (AJFs), which may provide lower life-cycle petroleum consumption and greenhouse gas (GHG) emissions than petroleum jet fuel. Here, this study presents well-to-wake (WTWa) results for four emerging AJFs: ethanol-to-jet (ETJ) from corn and corn stover, and sugar-to-jet (STJ) from corn stover via both biological and catalytic conversion. For the ETJ pathways, two plant designs were examined: integrated (processing corn or corn stover as feedstock) and distributed (processing ethanol as feedstock). Also, three H 2more » options for STJ via catalytic conversion are investigated: external H 2 from natural gas (NG) steam methane reforming (SMR), in situ H 2, and H 2 from biomass gasification. Results demonstrate that the feedstock is a key factor in the WTWa GHG emissions of ETJ: corn- and corn stover-based ETJ are estimated to produce WTWa GHG emissions that are 16 and 73%, respectively, less than those of petroleum jet. As for the STJ pathways, this study shows that STJ via biological conversion could generate WTWa GHG emissions 59% below those of petroleum jet. STJ via catalytic conversion could reduce the WTWa GHG emissions by 28% with H 2 from NG SMR or 71% with H 2 from biomass gasification than those of petroleum jet. This study also examines the impacts of co-product handling methods, and shows that the WTWa GHG emissions of corn stover-based ETJ, when estimated with a displacement method, are lower by 11 g CO 2e/MJ than those estimated with an energy allocation method. Corn- and corn stover-based ETJ as well as corn stover-based STJ show potentials to reduce WTWa GHG emissions compared to petroleum jet. Particularly, WTWa GHG emissions of STJ via catalytic conversion depend highly on the hydrogen source. On the other hand, ETJ offers unique opportunities to exploit extensive existing corn ethanol plants and infrastructure, and to provide a boost to staggering ethanol demand, which is largely being used as gasoline blendstock.« less

Well-to-wake analysis of ethanol-to-jet and sugar-to-jet pathways

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

Han, Jeongwoo; Tao, Ling; Wang, Michael

To reduce the environmental impacts of the aviation sector as air traffic grows steadily, the aviation industry has paid increasing attention to bio-based alternative jet fuels (AJFs), which may provide lower life-cycle petroleum consumption and greenhouse gas (GHG) emissions than petroleum jet fuel. Here, this study presents well-to-wake (WTWa) results for four emerging AJFs: ethanol-to-jet (ETJ) from corn and corn stover, and sugar-to-jet (STJ) from corn stover via both biological and catalytic conversion. For the ETJ pathways, two plant designs were examined: integrated (processing corn or corn stover as feedstock) and distributed (processing ethanol as feedstock). Also, three H 2more » options for STJ via catalytic conversion are investigated: external H 2 from natural gas (NG) steam methane reforming (SMR), in situ H 2, and H 2 from biomass gasification. Results demonstrate that the feedstock is a key factor in the WTWa GHG emissions of ETJ: corn- and corn stover-based ETJ are estimated to produce WTWa GHG emissions that are 16 and 73%, respectively, less than those of petroleum jet. As for the STJ pathways, this study shows that STJ via biological conversion could generate WTWa GHG emissions 59% below those of petroleum jet. STJ via catalytic conversion could reduce the WTWa GHG emissions by 28% with H 2 from NG SMR or 71% with H 2 from biomass gasification than those of petroleum jet. This study also examines the impacts of co-product handling methods, and shows that the WTWa GHG emissions of corn stover-based ETJ, when estimated with a displacement method, are lower by 11 g CO 2e/MJ than those estimated with an energy allocation method. Corn- and corn stover-based ETJ as well as corn stover-based STJ show potentials to reduce WTWa GHG emissions compared to petroleum jet. Particularly, WTWa GHG emissions of STJ via catalytic conversion depend highly on the hydrogen source. On the other hand, ETJ offers unique opportunities to exploit extensive existing corn ethanol plants and infrastructure, and to provide a boost to staggering ethanol demand, which is largely being used as gasoline blendstock.« less

Well-to-wake analysis of ethanol-to-jet and sugar-to-jet pathways.

PubMed

Han, Jeongwoo; Tao, Ling; Wang, Michael

2017-01-01

To reduce the environmental impacts of the aviation sector as air traffic grows steadily, the aviation industry has paid increasing attention to bio-based alternative jet fuels (AJFs), which may provide lower life-cycle petroleum consumption and greenhouse gas (GHG) emissions than petroleum jet fuel. This study presents well-to-wake (WTWa) results for four emerging AJFs: ethanol-to-jet (ETJ) from corn and corn stover, and sugar-to-jet (STJ) from corn stover via both biological and catalytic conversion. For the ETJ pathways, two plant designs were examined: integrated (processing corn or corn stover as feedstock) and distributed (processing ethanol as feedstock). Also, three H 2 options for STJ via catalytic conversion are investigated: external H 2 from natural gas (NG) steam methane reforming (SMR), in situ H 2 , and H 2 from biomass gasification. Results demonstrate that the feedstock is a key factor in the WTWa GHG emissions of ETJ: corn- and corn stover-based ETJ are estimated to produce WTWa GHG emissions that are 16 and 73%, respectively, less than those of petroleum jet. As for the STJ pathways, this study shows that STJ via biological conversion could generate WTWa GHG emissions 59% below those of petroleum jet. STJ via catalytic conversion could reduce the WTWa GHG emissions by 28% with H 2 from NG SMR or 71% with H 2 from biomass gasification than those of petroleum jet. This study also examines the impacts of co-product handling methods, and shows that the WTWa GHG emissions of corn stover-based ETJ, when estimated with a displacement method, are lower by 11 g CO 2 e/MJ than those estimated with an energy allocation method. Corn- and corn stover-based ETJ as well as corn stover-based STJ show potentials to reduce WTWa GHG emissions compared to petroleum jet. Particularly, WTWa GHG emissions of STJ via catalytic conversion depend highly on the hydrogen source. On the other hand, ETJ offers unique opportunities to exploit extensive existing corn ethanol plants and infrastructure, and to provide a boost to staggering ethanol demand, which is largely being used as gasoline blendstock.

Mild oxidation of methane to methanol or acetic acid on supported isolated rhodium catalysts

NASA Astrophysics Data System (ADS)

Shan, Junjun; Li, Mengwei; Allard, Lawrence F.; Lee, Sungsik; Flytzani-Stephanopoulos, Maria

2017-11-01

An efficient and direct method of catalytic conversion of methane to liquid methanol and other oxygenates would be of considerable practical value. However, it remains an unsolved problem in catalysis, as typically it involves expensive or corrosive oxidants or reaction media that are not amenable to commercialization. Although methane can be directly converted to methanol using molecular oxygen under mild conditions in the gas phase, the process is either stoichiometric (and therefore requires a water extraction step) or is too slow and low-yielding to be practical. Methane could, in principle, also be transformed through direct oxidative carbonylation to acetic acid, which is commercially obtained through methane steam reforming, methanol synthesis, and subsequent methanol carbonylation on homogeneous catalysts. However, an effective catalyst for the direct carbonylation of methane to acetic acid, which might enable the economical small-scale utilization of natural gas that is currently flared or stranded, has not yet been reported. Here we show that mononuclear rhodium species, anchored on a zeolite or titanium dioxide support suspended in aqueous solution, catalyse the direct conversion of methane to methanol and acetic acid, using oxygen and carbon monoxide under mild conditions. We find that the two products form through independent pathways, which allows us to tune the conversion: three-hour-long batch-reactor tests conducted at 150 degrees Celsius, using either the zeolite-supported or the titanium-dioxide-supported catalyst, yield around 22,000 micromoles of acetic acid per gram of catalyst, or around 230 micromoles of methanol per gram of catalyst, respectively, with selectivities of 60-100 per cent. We anticipate that these unusually high activities, despite still being too low for commercial application, may guide the development of optimized catalysts and practical processes for the direct conversion of methane to methanol, acetic acid and other useful chemicals.

Mild oxidation of methane to methanol or acetic acid on supported isolated rhodium catalysts

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

Shan, Junjun; Li, Mengwei; Allard, Lawrence F.

An efficient and direct method of catalytic conversion of methane to liquid methanol and other oxygenates would be of considerable practical value. However, it remains an unsolved problem in catalysis, as typically it involves expensive or corrosive oxidants or reaction media(5-8) that are not amenable to commercialization. Although methane can be directly converted to methanol using molecular oxygen under mild conditions in the gas phase, the process is either stoichiometric (and therefore requires a water extraction step) or is too slow and low-yielding to be practical. Methane could, in principle, also be transformed through direct oxidative carbonylation to acetic acid,more » which is commercially obtained through methane steam reforming, methanol synthesis, and subsequent methanol carbonylation on homogeneous catalysts. However, an effective catalyst for the direct carbonylation of methane to acetic acid, which might enable the economical small-scale utilization of natural gas that is currently flared or stranded, has not yet been reported. Here we show that mononuclear rhodium species, anchored on a zeolite or titanium dioxide support suspended in aqueous solution, catalyse the direct conversion of methane to methanol and acetic acid, using oxygen and carbon monoxide under mild conditions. Here, we find that the two products form through independent pathways, which allows us to tune the conversion: three-hour-long batch-reactor tests conducted at 150 degrees Celsius, using either the zeolitesupported or the titanium-dioxide-supported catalyst, yield around 22,000 micromoles of acetic acid per gram of catalyst, or around 230 micromoles of methanol per gram of catalyst, respectively, with selectivities of 60-100 per cent. Finally, we anticipate that these unusually high activities, despite still being too low for commercial application, may guide the development of optimized catalysts and practical processes for the direct conversion of methane to methanol, acetic acid and other useful chemicals.« less

Mild oxidation of methane to methanol or acetic acid on supported isolated rhodium catalysts

DOE PAGES

Shan, Junjun; Li, Mengwei; Allard, Lawrence F.; ...

2017-11-30

An efficient and direct method of catalytic conversion of methane to liquid methanol and other oxygenates would be of considerable practical value. However, it remains an unsolved problem in catalysis, as typically it involves expensive or corrosive oxidants or reaction media(5-8) that are not amenable to commercialization. Although methane can be directly converted to methanol using molecular oxygen under mild conditions in the gas phase, the process is either stoichiometric (and therefore requires a water extraction step) or is too slow and low-yielding to be practical. Methane could, in principle, also be transformed through direct oxidative carbonylation to acetic acid,more » which is commercially obtained through methane steam reforming, methanol synthesis, and subsequent methanol carbonylation on homogeneous catalysts. However, an effective catalyst for the direct carbonylation of methane to acetic acid, which might enable the economical small-scale utilization of natural gas that is currently flared or stranded, has not yet been reported. Here we show that mononuclear rhodium species, anchored on a zeolite or titanium dioxide support suspended in aqueous solution, catalyse the direct conversion of methane to methanol and acetic acid, using oxygen and carbon monoxide under mild conditions. Here, we find that the two products form through independent pathways, which allows us to tune the conversion: three-hour-long batch-reactor tests conducted at 150 degrees Celsius, using either the zeolitesupported or the titanium-dioxide-supported catalyst, yield around 22,000 micromoles of acetic acid per gram of catalyst, or around 230 micromoles of methanol per gram of catalyst, respectively, with selectivities of 60-100 per cent. Finally, we anticipate that these unusually high activities, despite still being too low for commercial application, may guide the development of optimized catalysts and practical processes for the direct conversion of methane to methanol, acetic acid and other useful chemicals.« less

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

Secondary Heat Exchanger Design and Comparison for Advanced High Temperature Reactor

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

Piyush Sabharwall; Ali Siahpush; Michael McKellar

2012-06-01

The goals of next generation nuclear reactors, such as the high temperature gas-cooled reactor and advance high temperature reactor (AHTR), are to increase energy efficiency in the production of electricity and provide high temperature heat for industrial processes. The efficient transfer of energy for industrial applications depends on the ability to incorporate effective heat exchangers between the nuclear heat transport system and the industrial process heat transport system. The need for efficiency, compactness, and safety challenge the boundaries of existing heat exchanger technology, giving rise to the following study. Various studies have been performed in attempts to update the secondarymore » heat exchanger that is downstream of the primary heat exchanger, mostly because its performance is strongly tied to the ability to employ more efficient conversion cycles, such as the Rankine super critical and subcritical cycles. This study considers two different types of heat exchangers—helical coiled heat exchanger and printed circuit heat exchanger—as possible options for the AHTR secondary heat exchangers with the following three different options: (1) A single heat exchanger transfers all the heat (3,400 MW(t)) from the intermediate heat transfer loop to the power conversion system or process plants; (2) Two heat exchangers share heat to transfer total heat of 3,400 MW(t) from the intermediate heat transfer loop to the power conversion system or process plants, each exchanger transfers 1,700 MW(t) with a parallel configuration; and (3) Three heat exchangers share heat to transfer total heat of 3,400 MW(t) from the intermediate heat transfer loop to the power conversion system or process plants. Each heat exchanger transfers 1,130 MW(t) with a parallel configuration. A preliminary cost comparison will be provided for all different cases along with challenges and recommendations.« less

Potential method for gas production: high temperature co-pyrolysis of lignite and sewage sludge with vacuum reactor and long contact time.

PubMed

Yang, Xiao; Yuan, Chengyong; Xu, Jiao; Zhang, Weijiang

2015-03-01

Lignite and sewage sludge were co-pyrolyzed in a vacuum reactor with high temperature (900°C) and long contact time (more than 2h). Beneficial synergetic effect on gas yield was clearly observed. Gas yield of blend fuel was evidently higher than that of both parent fuels. The gas volume yield, gas lower heating value (LHV), fixed carbon conversion and H2/CO ratio were 1.42 Nm(3)/kg(blend fuel), 10.57 MJ/Nm(3), 96.64% and 0.88% respectively, which indicated this new method a feasible one for gas production. It was possible that sewage sludge acted as gasification agents (CO2 and H2O) and catalyst (alkali and alkaline earth metals) provider during co-pyrolysis, promoting CO2-char and H2O-char gasification which, as a result, invited the improvement of gas volume yield, gas lower heating value and fixed carbon conversion. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

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.

Microwave Heating-Assisted Catalytic Dry Reforming of Methane to Syngas.

PubMed

Hamzehlouia, Sepehr; Jaffer, Shaffiq A; Chaouki, Jamal

2018-06-12

Natural gas is a robust and environmentally friendlier alternative to oil resources for energy and chemicals production. However, gas is distributed globally within shales and hydrates, which are generally remote and difficult reserves to produce. The accessibility, transportation, and distribution, therefore, bring major capital costs. With today's low and foreseen low price of natural gas, conversion of natural gas to higher value-added chemicals is highly sought by industry. Dry reforming of methane (DRM) is a technology pathway to convert two critical greenhouse gas components, CH 4 and CO 2 , to syngas, a commodity chemical feedstock. To date, the challenges of carbon deposition on the catalyst and evolution of secondary gas-phase products have prevented the commercial application of the DRM process. The recent exponential growth of renewable electricity resources, wind and solar power, provides a major opportunity to activate reactions by harnessing low-cost carbon-free energy via microwave-heating. This study takes advantage of differences in dielectric properties of materials to enable selective heating by microwave to create a large thermal gradient between a catalyst surface and the gas phase. Consequently, the reaction kinetics at the higher temperature catalyst surface are promoted while the reactions of lower temperature secondary gas-phase are reduced.

Gasification of refinery sludge in an updraft reactor for syngas production

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

Ahmed, Reem; Eldmerdash, Usama; Sinnathambi, Chandra M., E-mail: chandro@petronas.com.my

2014-10-24

The study probes into the investigation on gasification of dry refinery sludge. The details of the study includes; influence of operation time, oxidation temperature and equivalence ratios on carbon gas conversion rate, gasification efficiency, heating value and fuel gas yield are presented. The results show that, the oxidation temperature increased sharply up to 858°C as the operating time increased up to 36 min then bridging occurred at 39 min which cause drop in reaction temperature up to 819 °C. This bridging was found to affect also the syngas compositions, meanwhile as the temperature decreased the CO, H{sub 2}, CH{sub 4}more » compositions are also found to be decreases. Higher temperature catalyzed the reduction reaction (CO{sub 2}+C = 450 2CO), and accelerated the carbon conversion and gasification efficiencies, resulted in more solid fuel is converted to a high heating value gas fuel. The equivalence ratio of 0.195 was found to be the optimum value for carbon conversion and cold gas efficiencies, high heating value of gas, and fuel gas yield to reach their maximum values of 96.1 % and 53.7 %, 5.42 MJ Nm{sup −3} of, and 2.5 Nm{sup 3} kg{sup −1} respectively.« less

Gymnemic Acids Inhibit Hyphal Growth and Virulence in Candida albicans

PubMed Central

Vediyappan, Govindsamy; Dumontet, Vincent; Pelissier, Franck; d’Enfert, Christophe

2013-01-01

Candida albicans is an opportunistic and polymorphic fungal pathogen that causes mucosal, disseminated and invasive infections in humans. Transition from the yeast form to the hyphal form is one of the key virulence factors in C. albicans contributing to macrophage evasion, tissue invasion and biofilm formation. Nontoxic small molecules that inhibit C. albicans yeast-to-hypha conversion and hyphal growth could represent a valuable source for understanding pathogenic fungal morphogenesis, identifying drug targets and serving as templates for the development of novel antifungal agents. Here, we have identified the triterpenoid saponin family of gymnemic acids (GAs) as inhibitor of C. albicans morphogenesis. GAs were isolated and purified from Gymnema sylvestre leaves, the Ayurvedic traditional medicinal plant used to treat diabetes. Purified GAs had no effect on the growth and viability of C. albicans yeast cells but inhibited its yeast-to-hypha conversion under several hypha-inducing conditions, including the presence of serum. Moreover, GAs promoted the conversion of C. albicans hyphae into yeast cells under hypha inducing conditions. They also inhibited conidial germination and hyphal growth of Aspergillus sp. Finally, GAs inhibited the formation of invasive hyphae from C. albicans-infected Caenorhabditis elegans worms and rescued them from killing by C. albicans. Hence, GAs could be useful for various antifungal applications due to their traditional use in herbal medicine. PMID:24040201

Carbon dioxide from geothermal gas converted to biomass by cultivating coccoid cyanobacteria.

PubMed

Svavarsson, Halldor G; Valberg, Johannes E; Arnardottir, Hronn; Brynjolfsdottir, Asa

2017-07-11

The Blue Lagoon is a geothermal aquifer with a diverse ecosystem located within the Reykjanes UNESCO Global Geopark on Iceland's Reykjanes Peninsula. Blue Lagoon Ltd., which exploits the aquifer, isolated a strain of coccoid cyanobacteria Cyanobacterium aponinum (C. aponinum) from the geothermal fluid of the Blue Lagoon more than two decades ago. Since then Blue Lagoon Ltd. has cultivated it in a photobioreactor, for use as an active ingredient in its skin care products. Until recently, the cultivation of C. aponinum was achieved by feeding it on 99.99% (4N) bottled carbon dioxide (CO 2 ). In this investigation, C. aponinum was cultivated using unmodified, non-condensable geothermal gas (geogas) emitted from a nearby geothermal powerplant as the feed-gas instead of the 4N-gas. The geogas contains roughly 90% vol CO 2 and 2% vol hydrogen sulfide (H 2 S). A comparison of both CO 2 sources was made. It was observed that the use of geogas did enhance the conversion efficiency. A 13 weeks' average CO 2 conversion efficiency of C. aponinum was 43% and 31% when fed on geogas and 4N-gas, respectively. Despite the high H 2 S concentration in the geogas, sulfur accumulation in the cultivated biomass was similar for both gas sources. Our results provide a model of a CO 2 sequestration by photosynthetic conversion of otherwise unused geothermal emission gas into biomass.

In Situ Environmental TEM in Imaging Gas and Liquid Phase Chemical Reactions for Materials Research.

PubMed

Wu, Jianbo; Shan, Hao; Chen, Wenlong; Gu, Xin; Tao, Peng; Song, Chengyi; Shang, Wen; Deng, Tao

2016-11-01

Gas and liquid phase chemical reactions cover a broad range of research areas in materials science and engineering, including the synthesis of nanomaterials and application of nanomaterials, for example, in the areas of sensing, energy storage and conversion, catalysis, and bio-related applications. Environmental transmission electron microscopy (ETEM) provides a unique opportunity for monitoring gas and liquid phase reactions because it enables the observation of those reactions at the ultra-high spatial resolution, which is not achievable through other techniques. Here, the fundamental science and technology developments of gas and liquid phase TEM that facilitate the mechanistic study of the gas and liquid phase chemical reactions are discussed. Combined with other characterization tools integrated in TEM, unprecedented material behaviors and reaction mechanisms are observed through the use of the in situ gas and liquid phase TEM. These observations and also the recent applications in this emerging area are described. The current challenges in the imaging process are also discussed, including the imaging speed, imaging resolution, and data management. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Aqueous nitrite ion determination by selective reduction and gas phase nitric oxide chemiluminescence

NASA Technical Reports Server (NTRS)

Dunham, A. J.; Barkley, R. M.; Sievers, R. E.; Clarkson, T. W. (Principal Investigator)

1995-01-01

An improved method of flow injection analysis for aqueous nitrite ion exploits the sensitivity and selectivity of the nitric oxide (NO) chemilluminescence detector. Trace analysis of nitrite ion in a small sample (5-160 microL) is accomplished by conversion of nitrite ion to NO by aqueous iodide in acid. The resulting NO is transported to the gas phase through a semipermeable membrane and subsequently detected by monitoring the photoemission of the reaction between NO and ozone (O3). Chemiluminescence detection is selective for measurement of NO, and, since the detection occurs in the gas-phase, neither sample coloration nor turbidity interfere. The detection limit for a 100-microL sample is 0.04 ppb of nitrite ion. The precision at the 10 ppb level is 2% relative standard deviation, and 60-180 samples can be analyzed per hour. Samples of human saliva and food extracts were analyzed; the results from a standard colorimetric measurement are compared with those from the new chemiluminescence method in order to further validate the latter method. A high degree of selectivity is obtained due to the three discriminating steps in the process: (1) the nitrite ion to NO conversion conditions are virtually specific for nitrite ion, (2) only volatile products of the conversion will be swept to the gas phase (avoiding turbidity or color in spectrophotometric methods), and (3) the NO chemiluminescence detector selectively detects the emission from the NO + O3 reaction. The method is free of interferences, offers detection limits of low parts per billion of nitrite ion, and allows the analysis of up to 180 microL-sized samples per hour, with little sample preparation and no chromatographic separation. Much smaller samples can be analyzed by this method than in previously reported batch analysis methods, which typically require 5 mL or more of sample and often need chromatographic separations as well.

Life cycle assessment of two emerging sewage sludge-to-energy systems: evaluating energy and greenhouse gas emissions implications.

PubMed

Cao, Yucheng; Pawłowski, Artur

2013-01-01

A "cradle-to-grave" life cycle assessment was conducted to examine the energy and greenhouse gas (GHG) emission footprints of two emerging sludge-to-energy systems. One system employs a combination of anaerobic digestion (AD) and fast pyrolysis for bioenergy conversion, while the other excludes AD. Each system was divided into five process phases: plant construction, sludge pretreatment, sludge-to-bioenergy conversion, bioenergy utilizations and biochar management. Both systems achieved energy and GHG emission benefits, and the AD-involving system performed better than the AD-excluding system (5.30 vs. 0.63 GJ/t sludge in net energy gain and 0.63 vs. 0.47 t CO(2)eq/t sludge in emission credit for base case). Detailed contribution and sensitivity analyses were conducted to identify how and to what degree the different life-cycle phases are responsible for the energy and emission impacts. The energy and emission performances were significantly affected by variations in bioenergy production, energy requirement for sludge drying and end use of bioenergy. Copyright © 2012 Elsevier Ltd. All rights reserved.

Development and validation of an universal interface for compound-specific stable isotope analysis of chlorine (37Cl/35Cl) by GC-high-temperature conversion (HTC)-MS/IRMS.

PubMed

Renpenning, Julian; Hitzfeld, Kristina L; Gilevska, Tetyana; Nijenhuis, Ivonne; Gehre, Matthias; Richnow, Hans-Hermann

2015-03-03

A universal application of compound-specific isotope analysis of chlorine was thus far limited by the availability of suitable analysis techniques. In this study, gas chromatography in combination with a high-temperature conversion interface (GC-HTC), converting organic chlorine in the presence of H2 to gaseous HCl, was coupled to a dual-detection system, combining an ion trap mass spectrometer (MS) and isotope-ratio mass spectrometer (IRMS). The combination of the MS/IRMS detection enabled a detailed characterization, optimization, and online monitoring of the high-temperature conversion process via ion trap MS as well as a simultaneous chlorine isotope analysis by the IRMS. Using GC-HTC-MS/IRMS, chlorine isotope analysis at optimized conversion conditions resulted in very accurate isotope values (δ(37)Cl(SMOC)) for measured reference material with known isotope composition, including chlorinated ethylene, chloromethane, hexachlorocyclohexane, and trichloroacetic acids methyl ester. Respective detection limits were determined to be <15 nmol Cl on column with achieved precision of <0.3‰.

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

Molecule formation and infrared emission in fast interstellar shocks. I Physical processes

NASA Technical Reports Server (NTRS)

Hollenbach, D.; Mckee, C. F.

1979-01-01

The paper analyzes the structure of fast shocks incident upon interstellar gas of ambient density from 10 to the 7th per cu cm, while focusing on the problems of formation and destruction of molecules and infrared emission in the cooling, neutral post shock gas. It is noted that such fast shocks initially dissociate almost all preexisting molecules. Discussion covers the physical processes which determine the post shock structure between 10 to the 4 and 10 to the 2 K. It is shown that the chemistry of important molecular coolants H2, CO, OH, and H2O, as well as HD and CH, is reduced to a relatively small set of gas phase and grain surface reactions. Also, the chemistry follows the slow conversion of atomic hydrogen into H2, which primarily occurs on grain surfaces. The dependence of this H2 formation rate on grain and gas temperatures is examined and the survival of grains behind fast shocks is discussed. Post shock heating and cooling rates are calculated and an appropriate, analytic, universal cooling function is developed for molecules other than hydrogen which includes opacities from both the dust and the lines.

Factors affecting activated carbon-based catalysts for selective hydrogen sulfide oxidation

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

Li, Huixing; Monnell, J.D.; Alvin, M.A.

2008-09-01

The primary product of coal gasification processes is synthesis gas (syngas), a mixture of CO, H2, CO2, H2O and a number of minor components. Among the most significant minor components in syngas is hydrogen sulfide (H2S). In addition to its adverse environmental impact, H2S poisons the catalysts and hydrogen purification membranes, and causes severe corrosion in gas turbines. Technologies that can remove H2S from syngas and related process streams are, therefore, of considerable practical interest. To meet this need, we work towards understanding the mechanism by which prospective H2S catalysts perform in simulated fuel gas conditions. Specifically, we show thatmore » for low-temperature gas clean-up (~1408C) using activated carbon fibers and water plays a significant role in H2S binding and helps to prolong the lifetime of the material. Basic surface functional groups were found to be imperative for significant conversion of H2S to daughter compounds, whereas metal oxides (La and Ce) did little to enhance this catalysis. We show that although thermal regeneration of the material is possible, the regenerated material has a substantially lower catalytic and sorption capacity.« less

University Capstone Project: Enhanced Initiation Techniques for Thermochemical Energy Conversion

DTIC Science & Technology

2013-03-01

technologies such as scramjets, gas turbine engines (relight and afterburner ignition), and pulsed detonation engines ( PDEs ) because of the limited...events in a flow tube were recorded, and the PDE engine was fired while monitoring ignition time and wave speed throughout the detonation process...long steel tube fitted with a 36” long, 2” x 2” square polycarbonate test section is used in place of the instrumented detonation tube. The PDE

Optimization and economic evaluation of industrial gas production and combined heat and power generation from gasification of corn stover and distillers grains.

PubMed

Kumar, Ajay; Demirel, Yasar; Jones, David D; Hanna, Milford A

2010-05-01

Thermochemical gasification is one of the most promising technologies for converting biomass into power, fuels and chemicals. The objectives of this study were to maximize the net energy efficiency for biomass gasification, and to estimate the cost of producing industrial gas and combined heat and power (CHP) at a feedrate of 2000kg/h. Aspen Plus-based model for gasification was combined with a CHP generation model, and optimized using corn stover and dried distillers grains with solubles (DDGS) as the biomass feedstocks. The cold gas efficiencies for gas production were 57% and 52%, respectively, for corn stover and DDGS. The selling price of gas was estimated to be $11.49 and $13.08/GJ, respectively, for corn stover and DDGS. For CHP generation, the electrical and net efficiencies were as high as 37% and 88%, respectively, for corn stover and 34% and 78%, respectively, for DDGS. The selling price of electricity was estimated to be $0.1351 and $0.1287/kWh for corn stover and DDGS, respectively. Overall, high net energy efficiencies for gas and CHP production from biomass gasification can be achieved with optimized processing conditions. However, the economical feasibility of these conversion processes will depend on the relative local prices of fossil fuels. Copyright 2009 Elsevier Ltd. All rights reserved.

Comparison of coal reactivityduring conversion into different oxidizing medium

NASA Astrophysics Data System (ADS)

Korotkikh, A. G.; Slyusarskiy, K. V.; Larionov, K. B.; Osipov, V. I.

2016-10-01

Acoal conversion process of different coal samples into three different types of oxidizing medium (argon, air and steam) were studied by means of thermogravimetry. Two coal types with different metamorphism degree (lignite and bituminous coal) were used. The experimental procedure was carried out in non-isothermal conditions in temperature range from 373 K to 1273 K with 20 K/min heating rate. Purge gas consisted of argon and oxidizer with volumetric ratio 1:24 and had 250 ml/min flow rate.The ignition and burnout indexes were calculated to evaluate sample reactivity at different oxidizing mediums. The highest reactivity coefficient values in same atmosphere were obtained for lignite. It was caused by higher particle special surface area and volatile matter content.

Biomass [updated

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

Turhollow Jr, Anthony F

2016-01-01

Biomass resources and conversion technologies are diverse. Substantial biomass resources exist including woody crops, herbaceous perennials and annuals, forest resources, agricultural residues, and algae. Conversion processes available include fermentation, gasification, pyrolysis, anaerobic digestion, combustion, and transesterification. Bioderived products include liquid fuels (e.g. ethanol, biodiesel, and gasoline and diesel substitutes), gases, electricity, biochemical, and wood pellets. At present the major sources of biomass-derived liquid fuels are from first generation biofuels; ethanol from maize and sugar cane (89 billion L in 2013) and biodiesel from vegetable oils and fats (24 billion liters in 2011). For other than traditional uses, policy in themore » forms of mandates, targets, subsidies, and greenhouse gas emission targets has largely been driving biomass utilization. Second generation biofuels have been slow to take off.« less

The hydrology of northern peatlands as affected by biogenic gas: Current developments and research needs

USGS Publications Warehouse

Rosenberry, D.O.; Glaser, P.H.; Siegel, D.I.

2006-01-01

Recent research indicates that accumulation and release of biogenic gas from northern peatlands may substantially affect future climate. Sudden release of free-phase gas bubbles into the atmosphere may preclude the conversion of methane to carbon dioxide in the uppermost oxic layer of the peat, resulting in greater contribution of methane to the atmosphere than is currently estimated. The hydrology of these peatlands also affects and is affected by this process, especially when gas is released suddenly and episodically. Indirect hydrological evidence indicates that ebullitive gas releases are relatively frequent in some peatlands and time-averaged rates may be significantly greater than diffusive releases. Estimates of free-phase gas contained in peat have ranged from 0 to nearly 20% of the peat volume. Abrupt changes in the volume of gas may alter hydraulic gradients and movement of water and solutes in peat, which in turn could alter composition and fluxes of the gas. Peat surfaces also move vertically and horizontally in response to accumulation and release of free-phase gas. Future research should address the distribution, temporal variability, and relative significance of ebullition in peatlands and the consequent hydrological responses to these gas-emission events. Copyright ?? 2006 John Wiley & Sons, Ltd.

49 CFR 192.14 - Conversion to service subject to this part.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Conversion to service subject to this part. 192.14 Section 192.14 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS General § 192.14 Conversion...

Solid-State Gas Sensors: Sensor System Challenges in the Civil Security Domain.

PubMed

Müller, Gerhard; Hackner, Angelika; Beer, Sebastian; Göbel, Johann

2016-01-20

The detection of military high explosives and illicit drugs presents problems of paramount importance in the fields of counter terrorism and criminal investigation. Effectively dealing with such threats requires hand-portable, mobile and affordable instruments. The paper shows that solid-state gas sensors can contribute to the development of such instruments provided the sensors are incorporated into integrated sensor systems, which acquire the target substances in the form of particle residue from suspect objects and which process the collected residue through a sequence of particle sampling, solid-vapor conversion, vapor detection and signal treatment steps. Considering sensor systems with metal oxide gas sensors at the backend, it is demonstrated that significant gains in sensitivity, selectivity and speed of response can be attained when the threat substances are sampled in particle as opposed to vapor form.

Solid-State Gas Sensors: Sensor System Challenges in the Civil Security Domain

PubMed Central

Müller, Gerhard; Hackner, Angelika; Beer, Sebastian; Göbel, Johann

2016-01-01

The detection of military high explosives and illicit drugs presents problems of paramount importance in the fields of counter terrorism and criminal investigation. Effectively dealing with such threats requires hand-portable, mobile and affordable instruments. The paper shows that solid-state gas sensors can contribute to the development of such instruments provided the sensors are incorporated into integrated sensor systems, which acquire the target substances in the form of particle residue from suspect objects and which process the collected residue through a sequence of particle sampling, solid-vapor conversion, vapor detection and signal treatment steps. Considering sensor systems with metal oxide gas sensors at the backend, it is demonstrated that significant gains in sensitivity, selectivity and speed of response can be attained when the threat substances are sampled in particle as opposed to vapor form. PMID:28787865

Space electric power design study. [laser energy conversion

NASA Technical Reports Server (NTRS)

Martini, W. R.

1976-01-01

The conversion of laser energy to electrical energy is discussed. Heat engines in which the laser heats the gas inside the engine through a window as well as heat engines in which the gas is heated by a thermal energy storage reservoir which has been heated by laser radiation are both evaluated, as well as the necessary energy storage, transmission and conversion components needed for a full system. Preliminary system concepts are presented and a recommended development program is outlined. It appears possible that a free displacer Stirling engine operating directly a linear electric generator can convert 65% of the incident laser energy into electricity.

Changes in Trace Gas Nitrogen Emissions as a Response to Ecosystem Type Conversion in a Semi-Arid Climate.

NASA Astrophysics Data System (ADS)

Andrews, H.; Eberwein, J. R.; Jenerette, D.

2016-12-01

As humans continue to introduce exotic plants and to alter climate and fire regimes in semi-arid ecosystems, many plant communities have begun to shift from perennial forbs and shrubs to annual grasses with different functional traits. Shifts in plant types are also associated with shifts in microclimate, microbial activity, and litter inputs, all of which contribute to the efficiency of nitrogen processing and the magnitude of trace gas emissions (NOx and N2O), which are increasingly important fluxes in water-limited systems. Here, we explored how changes in plant litter impact trace gas emissions, asking the question: How does conversion from a native shrubland to exotic grassland ecosystem alter NOx and N2O fluxes in a semi-arid climate? We posed two hypotheses to explain the impacts of different types of litter on soils disturbed by exotic grasses and those that were still considered shrublands: 1.) Soils that have undergone conversion by exotic grasses release higher amounts of NOx and N2O than do those of unconverted shrublands, due to disruptions of native plant and soil processes by exotic grasses, and 2.) Because litter of exotic grasses has lower C:N than that of shrubs, litter inputs from exotic grasses will increase NOx and N2O emissions from soils more than will litter inputs from shrubs. As a preliminary study, we experimentally wetted mesocosms in a laboratory incubation containing converted and unconverted soils that had been mixed with no litter or either exotic grass or coastal sage scrub (CSS) litter. We measured N2O fluxes from mesocosms over a 48-hour period. 24 hours after wetting, samples with grass litter produced higher amounts of N2O than those with CSS litter; similarly, converted soils produced higher amounts of N2O than unconverted soils. These two effects combined resulted in exotic grassland conditions (converted soils with exotic grass litter) producing 10 times the amount of N2O as those containing native shrubland conditions (unconverted soils with CSS litter). Additionally, soils with no litter peaked in N2O emissions earlier than those with litter (12 hours after wetting compared to 24 hours after wetting). Following preliminary results, we suggest that differences in plant traits, such as litter, play a significant role in the magnitude and timing of trace gas nitrogen emissions.

Giant seafloor craters formed by hydrate-controlled large-scale methane expulsion from the Arctic seafloor after ice sheet retreat

NASA Astrophysics Data System (ADS)

Andreassen, K.; Hubbard, A.; Patton, H.; Vadakkepuliyambatta, S.; Winsborrow, M.; Plaza-Faverola, A. A.; Serov, P.

2017-12-01

Large-scale methane releases from thawing Arctic gas hydrates is a major concern, yet the processes and fluxes involved remain elusive. We present geophysical data indicating two contrasting processes of natural methane emissions from the seafloor of the northern Barents Sea, Polar North Atlantic. Abundant gas flares, acoustically imaged in the water column reveal slow, gradual release of methane bubbles, a process that is commonly documented from nearby areas, elsewhere in the Arctic and along continental margins worldwide. Conversely, giant craters across the study area indicate a very different process. We propose that these are blow-out craters, formed through large-scale, abrupt methane expulsion induced when gas hydrates destabilized after the Barents Sea Ice Sheet retreated from the area. The data reveal over 100 giant seafloor craters within an area of 440 km2. These are up to 1000 m in diameter, 30 m deep and with a semi-circular to elliptical shape. We also identified numerous large seafloor mounds, which we infer to have formed by the expansion of gas hydrate accumulations within the shallow subsurface, so-called gas hydrate pingos. These are up to 1100 m wide and 20 m high. Smaller craters and mounds < 200 m wide and with varying relief are abundant across the study site. The empirical observations and analyses are combined with numerical modelling of ice sheet, isostatic and gas hydrate evolution and indicate that during glaciation, natural gas migrating from underlying hydrocarbon reservoirs was stored as subglacial gas hydrates. On ice sheet retreat, methane from these hydrate reservoirs and underlying free gas built up and abruptly released, forming the giant mounds and craters observed in the study area today. Petroleum basins are abundant beneath formerly and presently glaciated regions. We infer that episodes of subglacial sequestration of gas hydrates and underlying free gas and subsequent abrupt expulsions were common and widespread throughout Quaternary glacial cycles. The presented conceptual model for the evolution of giant craters can also serve as an analogue for future destabilization of glacially influenced hydrate reservoirs.

Life cycle water footprint of hydrogenation-derived renewable diesel production from lignocellulosic biomass.

PubMed

Wong, Alain; Zhang, Hao; Kumar, Amit

2016-10-01

The conversion of lignocellulosic biomass to biofuel requires water. This study is focused on the production of hydrogenation-derived renewable diesel (HDRD) from lignocellulosic biomass. Although there has been considerable focus on the assessment of greenhouse gas (GHG) emissions, there is limited work on the assessment of the life cycle water footprint of HDRD production. This paper presents a life cycle water consumption study on lignocellulosic biomass to HDRD via pyrolysis and hydrothermal liquefaction (HTL) processes. The results of this study show that whole tree (i.e., tree chips) biomass has water requirements of 497.79 L/MJ HDRD and 376.16 L/MJ HDRD for production through fast pyrolysis and the HTL process, respectively. Forest residues (i.e., chips from branches and tops generated during logging operations) have water requirements of 338.58 L/MJ HDRD and 255.85 L/MJ HDRD for production through fast pyrolysis and the HTL process, respectively. Agricultural residues (i.e., straw from wheat, oats, and barley), which are more water efficient, have water requirements of 83.7 L/MJ HDRD and 59.1 L/MJ HDRD through fast pyrolysis and the HTL process, respectively. Differences in water use between feedstocks and conversion processes indicate that the choices of biomass feedstock and conversion pathway water efficiency are crucial factors affecting water use efficiency of HDRD production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mathematical Modeling and Optimization of Gaseous Fuel Processing as a Basic Technology for Long-distance Energy Transportation: The Use of Methanol and Dimethyl Ether as Energy Carriers.

NASA Astrophysics Data System (ADS)

Tyurina, E. A.; Mednikov, A. S.

2017-11-01

The paper presents the results of studies on the perspective technologies of natural gas conversion to synthetic liquid fuel (SLF) at energy-technology installations for combined production of SLF and electricity based on their detailed mathematical models. The technologies of the long-distance transport of energy of natural gas from large fields to final consumers are compared in terms of their efficiency. This work was carried out at Melentiev Energy Systems Institute of Siberian Branch of the Russian Academy of Sciences and supported by Russian Science Foundation via grant No 16-19-10174

Method of producing gaseous products using a downflow reactor

DOEpatents

Cortright, Randy D; Rozmiarek, Robert T; Hornemann, Charles C

2014-09-16

Reactor systems and methods are provided for the catalytic conversion of liquid feedstocks to synthesis gases and other noncondensable gaseous products. The reactor systems include a heat exchange reactor configured to allow the liquid feedstock and gas product to flow concurrently in a downflow direction. The reactor systems and methods are particularly useful for producing hydrogen and light hydrocarbons from biomass-derived oxygenated hydrocarbons using aqueous phase reforming. The generated gases may find used as a fuel source for energy generation via PEM fuel cells, solid-oxide fuel cells, internal combustion engines, or gas turbine gensets, or used in other chemical processes to produce additional products. The gaseous products may also be collected for later use or distribution.

Hydro-geomechanical behaviour of gas-hydrate bearing soils during gas production through depressurization and CO2 injection

NASA Astrophysics Data System (ADS)

Deusner, C.; Gupta, S.; Kossel, E.; Bigalke, N.; Haeckel, M.

2015-12-01

Results from recent field trials suggest that natural gas could be produced from marine gas hydrate reservoirs at compatible yields and rates. It appears, from a current perspective, that gas production would essentially be based on depressurization and, when facing suitable conditions, be assisted by local thermal stimulation or gas hydrate conversion after injection of CO2-rich fluids. Both field trials, onshore in the Alaska permafrost and in the Nankai Trough offshore Japan, were accompanied by different technical issues, the most striking problems resulting from un-predicted geomechanical behaviour, sediment destabilization and catastrophic sand production. So far, there is a lack of experimental data which could help to understand relevant mechanisms and triggers for potential soil failure in gas hydrate production, to guide model development for simulation of soil behaviour in large-scale production, and to identify processes which drive or, further, mitigate sand production. We use high-pressure flow-through systems in combination with different online and in situ monitoring tools (e.g. Raman microscopy, MRI) to simulate relevant gas hydrate production scenarios. Key components for soil mechanical studies are triaxial systems with ERT (Electric resistivity tomography) and high-resolution local strain analysis. Sand production control and management is studied in a novel hollow-cylinder-type triaxial setup with a miniaturized borehole which allows fluid and particle transport at different fluid injection and flow conditions. Further, the development of a large-scale high-pressure flow-through triaxial test system equipped with μ-CT is ongoing. We will present results from high-pressure flow-through experiments on gas production through depressurization and injection of CO2-rich fluids. Experimental data are used to develop and parametrize numerical models which can simulate coupled process dynamics during gas-hydrate formation and gas production.

The Effect of Surfactant and Compatibilizer on Inorganic Loading and Properties of PPO-based EPMM Membranes

NASA Astrophysics Data System (ADS)

Bissadi, Golnaz

Hybrid membranes represent a promising alternative to the limitations of organic and inorganic materials for high productivity and selectivity gas separation membranes. In this study, the previously developed concept of emulsion-polymerized mixed matrix (EPMM) membranes was further advanced by investigating the effects of surfactant and compatibilizer on inorganic loading in poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)-based EPMM membranes, in which inorganic part of the membranes originated from tetraethylorthosilicate (TEOS). The polymerization of TEOS, which consists of hydrolysis of TEOS and condensation of the hydrolyzed TEOS, was carried out as (i) one- and (ii) two-step processes. In the one-step process, the hydrolysis and condensation take place in the same environment of a weak acid provided by the aqueous solution of aluminum hydroxonitrate and sodium carbonate. In the two-step process, the hydrolysis takes place in the environment of a strong acid (solution of hydrochloric acid), whereas the condensation takes place in weak base environment obtained by adding excess of the ammonium hydroxide solution to the acidic solution of the hydrolyzed TEOS. For both one- and two-step processes, the emulsion polymerization of TEOS was carried out in two types of emulsions made of (i) pure trichloroethylene (TCE) solvent, and (ii) 10 w/v% solution of PPO in TCE, using different combinations of the compatibilizer (ethanol) and the surfactant (n-octanol). The experiments with pure TCE, which are referred to as a gravimetric powder method (GPM) allowed assessing the effect of different experimental parameters on the conversion of TEOS. The GPM tests also provided a guide for the synthesis of casting emulsions containing PPO, from which the EPMM membranes were prepared using a spin coating technique. The synthesized EPMM membranes were characterized using 29Si nuclear magnetic resonance (29Si NMR), differential scanning calorimetry (DSC), inductively coupled plasma mass spectrometry (ICP-MS), and gas permeation measurements carried out in a constant pressure (CP) system. The 29Si NMR analysis verified polymerization of TEOS in the emulsions made of pure TCE, and the PPO solution in TCE. The conversions of TEOS in the two-step process in the two types of emulsions were very close to each other. In the case of the one-step process, the conversions in the TCE emulsion were significantly greater than those in the emulsion of the PPO solution in TCE. Consequently, the conversions of TEOS in the EPMM membranes made in the two-step process were greater than those in the EPMM membranes made in the one-step process. The latter ranged between 10 - 20%, while the highest conversion in the two-step process was 74% in the presence of pure compatibilizer with no surfactant. Despite greater conversions and hence the greater inorganic loadings, the EPMM membranes prepared in the two-step process had glass transition temperatures (Tg) only slightly greater than the reference PPO membranes. In contrast, despite relatively low inorganic loadings, the EPMM membranes prepared in the one-step process had Tgs markedly greater than PPO, and showed the expected trend of an increase in Tg with the inorganic loading. These results indicate that in the case of the one-step process the polymerized TEOS was well integrated with the PPO chains and the interactions between the two phases lead to high Tgs. On the other hand, this was not the case for the EPMM membranes prepared in the two-step process, suggesting possible phase separation between the polymerized TEOS and the organic phase. The latter was confirmed by detecting no selectivity in the EPMM membranes prepared by the two-step process. In contrast, the EPMM membranes prepared in the one-step process in the presence of the compatibilizer and no surfactant showed 50% greater O2 permeability coefficient and a slightly greater O2/N2 permeability ratio compared to the reference PPO membranes.

Methylal and methylal-diesel blended fuels for use in compression-ignition engines

DOT National Transportation Integrated Search

2000-06-21

Gas-to-liquids catalytic conversion technologies show promise for liberating stranded natural gas reserves and for achieving energy diversity worldwide. Some gas-toliquids : products are used as transportation fuels and as blendstocks for upgra...

Process for removing copper in a recoverable form from solid scrap metal

DOEpatents

Hartman, Alan D.; Oden, Laurance L.; White, Jack C.

1995-01-01

A process for removing copper in a recoverable form from a copper/solid ferrous scrap metal mix is disclosed. The process begins by placing a copper/solid ferrous scrap metal mix into a reactor vessel. The atmosphere within the reactor vessel is purged with an inert gas or oxidizing while the reactor vessel is heated in the area of the copper/solid ferrous scrap metal mix to raise the temperature within the reactor vessel to a selected elevated temperature. Air is introduced into the reactor vessel and thereafter hydrogen chloride is introduced into the reactor vessel to obtain a desired air-hydrogen chloride mix. The air-hydrogen chloride mix is operable to form an oxidizing and chloridizing atmosphere which provides a protective oxide coating on the surface of the solid ferrous scrap metal in the mix and simultaneously oxidizes/chloridizes the copper in the mix to convert the copper to a copper monochloride gas for transport away from the solid ferrous scrap metal. After the copper is completely removed from the copper/solid ferrous scrap metal mix, the flows of air and hydrogen chloride are stopped and the copper monochloride gas is collected for conversion to a recoverable copper species.

Tdp studies and tests for C. A. Energia Electrica de Venezuela (enelven) at planta ramon laguna, units RL-17 and RL-10. Volume 1. Executive summary, RL-17 test report, and gas conversion proposals. Export trade information

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

Not Available

1991-03-28

The study, conducted by Babcock and Wilcox, was funded by the U.S. Trade and Development agency on behalf of Enelven. In order to maximize generated power output and minimize operating costs at Planta Ramon Laguna, tests were done to evaluate the condition of equipment at the plant. In order to identify any damage and determine the operating output of each unit, assessments were done of the furnaces, boilers, generators and boiler feed pumps being used in the plant. The report presents the results of these tests. This is the first of three volumes and it is divided into the followingmore » sections: (1) Executive Summary; (2) Hydrogen Damage Assessment; (3) RL-17 Gas Conversion Proposal; (4) RL-10 and RL-11 Gas Conversion Proposals.« less

Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 4: Open recuperated and bottomed gas turbine cycles. [performance prediction and energy conversion efficiency of gas turbines in electric power plants (thermodynamic cycles)

NASA Technical Reports Server (NTRS)

Amos, D. J.; Grube, J. E.

1976-01-01

Open-cycle recuperated gas turbine plant with inlet temperatures of 1255 to 1644 K (1800 to 2500 F) and recuperators with effectiveness values of 0, 70, 80 and 90% are considered. A 1644 K (2500 F) gas turbine would have a 33.5% plant efficiency in a simple cycle, 37.6% in a recuperated cycle and 47.6% when combined with a sulfur dioxide bottomer. The distillate burning recuperated plant was calculated to produce electricity at a cost of 8.19 mills/MJ (29.5 mills/kWh). Due to their low capital cost $170 to 200 $/kW, the open cycle gas turbine plant should see duty for peaking and intermediate load duty.

Catalytic processing of lactic acid over Pt/Nb(2)O(5).

PubMed

Serrano-Ruiz, Juan Carlos; Dumesic, James A

2009-01-01

Dilute aqueous solutions of lactic acid (30 %wt.) can be catalytically processed at 573 K and 57 bar over a low-metal-content Pt(0.1 %)/Nb(2)O(5) catalyst in a spontaneously separating organic phase rich in valuable products such as C(4)-C(7) ketones. An increase in the lactic acid concentration to 60 wt % allows conversion of approximately 50 % of the carbon feed in this organic layer, while maintaining good stability of the catalyst. Experiments at low conversion showed that lactic acid reacts first over Pt(0.1 %)/Nb(2)O(5) to produce acetaldehyde and propanoic acid (along with CO and CO(2) in the gas phase). These compounds (less oxygenated than lactic acid but still reactive) are the key intermediates in the overall process, and they react differently depending on the nature of the catalyst support. In particular, reaction kinetics studies with propanoic acid as feed showed that Pt(0.1 %)/Nb(2)O(5) favored the formation of pentanones by ketonization reactions, whereas a monofunctional Pt(0.1 %)/carbon catalyst produced ethane and CO(x) by decomposition reactions. In the same manner, acetaldehyde was preferentially hydrogenated to ethanol over Pt(0.1 %)/carbon, whereas the presence of niobia allowed this intermediate to react (by successive aldol condensations) to form C(4)-C(7) condensation products stored in the organic phase. Finally, reaction pathways are proposed to explain the catalytic processing of lactic acid over bifunctional Pt(0.1 %)/Nb(2)O(5). In this scheme, metal sites catalyze hydrogenation reactions and niobia promotes C--C coupling processes (ketonization and aldol condensation), in contrast to C--C cleavage reactions which take place preferentially over Pt(0.1 %)/carbon and lead to loss of carbon in the gas effluent as CO, CO(2), and methane.

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

Towards the interaction between calcium carbide and water during gas-chromatographic determination of trace moisture in ultra-high purity ammonia.

PubMed

Trubyanov, Maxim M; Mochalov, Georgy M; Suvorov, Sergey S; Puzanov, Egor S; Petukhov, Anton N; Vorotyntsev, Ilya V; Vorotyntsev, Vladimir M

2018-07-27

The current study focuses on the processes involved during the flow conversion of water into acetylene in a calcium carbide reaction cell for the trace moisture analysis of ammonia by reaction gas chromatography. The factors negatively affecting the reproducibility and the accuracy of the measurements are suggested and discussed. The intramolecular reaction of the HOCaCCH intermediate was found to be a side reaction producing background acetylene during the contact of wet ammonia gas with calcium carbide. The presence of the HOCaCCH intermediate among the reaction products is confirmed by an FTIR spectral study of calcium carbide powder exposed to wet gas. The side reaction kinetics is evaluated experimentally and its influence on the results of the gas chromatographic measurements is discussed in relation to the determination of the optimal operating parameters for ammonia analysis. The reaction gas chromatography method for the trace moisture measurements in an ammonia matrix was experimentally compared to an FTIR long-path length gas cell technique to evaluate the accuracy limitations and the resource intensity. Copyright © 2018 Elsevier B.V. All rights reserved.

Method of producing a colloidal fuel from coal and a heavy petroleum fraction. [partial liquefaction of coal in slurry, filtration and gasification of residue

DOEpatents

Longanbach, J.R.

1981-11-13

A method is provided for combining coal as a colloidal suspension within a heavy petroleum fraction. The coal is broken to a medium particle size and is formed into a slurry with a heavy petroleum fraction such as a decanted oil having a boiling point of about 300 to 550/sup 0/C. The slurry is heated to a temperature of 400 to 500/sup 0/C for a limited time of only about 1 to 5 minutes before cooling to a temperature of less than 300/sup 0/C. During this limited contact time at elevated temperature the slurry can be contacted with hydrogen gas to promote conversion. The liquid phase containing dispersed coal solids is filtered from the residual solids and recovered for use as a fuel or feed stock for other processes. The residual solids containing some carbonaceous material are further processed to provide hydrogen gas and heat for use as required in this process.

Detecting gas hydrate behavior in crude oil using NMR.

PubMed

Gao, Shuqiang; House, Waylon; Chapman, Walter G

2006-04-06

Because of the associated experimental difficulties, natural gas hydrate behavior in black oil is poorly understood despite its grave importance in deep-water flow assurance. Since the hydrate cannot be visually observed in black oil, traditional methods often rely on gas pressure changes to monitor hydrate formation and dissociation. Because gases have to diffuse through the liquid phase for hydrate behavior to create pressure responses, the complication of gas mass transfer is involved and hydrate behavior is only indirectly observed. This pressure monitoring technique encounters difficulties when the oil phase is too viscous, the amount of water is too small, or the gas phase is absent. In this work we employ proton nuclear magnetic resonance (NMR) spectroscopy to observe directly the liquid-to-solid conversion of the water component in black oil emulsions. The technique relies on two facts. The first, well-known, is that water becomes essentially invisible to liquid state NMR as it becomes immobile, as in hydrate or ice formation. The second, our recent finding, is that in high magnetic fields of sufficient homogeneity, it is possible to distinguish water from black oil spectrally by their chemical shifts. By following changes in the area of the water peak, the process of hydrate conversion can be measured, and, at lower temperatures, the formation of ice. Taking only seconds to accomplish, this measurement is nearly direct in contrast to conventional techniques that measure the pressure changes of the whole system and assume these changes represent formation or dissociation of hydrates - rather than simply changes in solubility. This new technique clearly can provide accurate hydrate thermodynamic data in black oils. Because the technique measures the total mobile water with rapidity, extensions should prove valuable in studying the dynamics of phase transitions in emulsions.

Energy Conversion and Storage Requirements for Hybrid Electric Aircraft

NASA Technical Reports Server (NTRS)

Misra, Ajay

2016-01-01

Among various options for reducing greenhouse gases in future large commercial aircraft, hybrid electric option holds significant promise. In the hybrid electric aircraft concept, gas turbine engine is used in combination with an energy storage system to drive the fan that propels the aircraft, with gas turbine engine being used for certain segments of the flight cycle and energy storage system being used for other segments. The paper will provide an overview of various energy conversion and storage options for hybrid electric aircraft. Such options may include fuel cells, batteries, super capacitors, multifunctional structures with energy storage capability, thermoelectric, thermionic or a combination of any of these options. The energy conversion and storage requirements for hybrid electric aircraft will be presented. The role of materials in energy conversion and storage systems for hybrid electric aircraft will be discussed.

Nonequilibrium dynamics of the phonon gas in ultrafast-excited antimony

NASA Astrophysics Data System (ADS)

Krylow, Sergej; Zijlstra, Eeuwe S.; Kabeer, Fairoja Cheenicode; Zier, Tobias; Bauerhenne, Bernd; Garcia, Martin E.

2017-12-01

The ultrafast relaxation dynamics of a nonequilibrium phonon gas towards thermal equilibrium involves many-body collisions that cannot be properly described by perturbative approaches. Here, we develop a nonperturbative method to elucidate the microscopic mechanisms underlying the decay of laser-excited coherent phonons in the presence of electron-hole pairs, which so far are not fully understood. Our theory relies on ab initio molecular dynamics simulations on laser-excited potential-energy surfaces. Those simulations are compared with runs in which the laser-excited coherent phonon is artificially deoccupied. We apply this method to antimony and show that the decay of the A1 g phonon mode at low laser fluences can be accounted mainly to three-body down-conversion processes of an A1 g phonon into acoustic phonons. For higher excitation strengths, however, we see a crossover to a four-phonon process, in which two A1 g phonons decay into two optical phonons.

Analysis of irradiated U-7wt%Mo dispersion fuel microstructures using automated image processing

DOE PAGES

Collette, R.; King, J.; Buesch, C.; ...

2016-04-01

The High Performance Research Reactor Fuel Development (HPPRFD) program is responsible for developing low enriched uranium (LEU) fuel substitutes for high performance reactors fueled with highly enriched uranium (HEU) that have not yet been converted to LEU. The uranium-molybdenum (U-Mo) fuel system was selected for this effort. In this study, fission gas pore segmentation was performed on U-7wt%Mo dispersion fuel samples at three separate fission densities using an automated image processing interface developed in MATLAB. Pore size distributions were attained that showed both expected and unexpected fission gas behavior. In general, it proved challenging to identify any dominant trends whenmore » comparing fission bubble data across samples from different fuel plates due to varying compositions and fabrication techniques. Here, the results exhibited fair agreement with the fission density vs. porosity correlation developed by the Russian reactor conversion program.« less

Analysis of irradiated U-7wt%Mo dispersion fuel microstructures using automated image processing

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

Collette, R.; King, J.; Buesch, C.

The High Performance Research Reactor Fuel Development (HPPRFD) program is responsible for developing low enriched uranium (LEU) fuel substitutes for high performance reactors fueled with highly enriched uranium (HEU) that have not yet been converted to LEU. The uranium-molybdenum (U-Mo) fuel system was selected for this effort. In this study, fission gas pore segmentation was performed on U-7wt%Mo dispersion fuel samples at three separate fission densities using an automated image processing interface developed in MATLAB. Pore size distributions were attained that showed both expected and unexpected fission gas behavior. In general, it proved challenging to identify any dominant trends whenmore » comparing fission bubble data across samples from different fuel plates due to varying compositions and fabrication techniques. Here, the results exhibited fair agreement with the fission density vs. porosity correlation developed by the Russian reactor conversion program.« less

Analysis of Fuel Injection and Atomization of a Hybrid Air-Blast Atomizer.

NASA Astrophysics Data System (ADS)

Ma, Peter; Esclape, Lucas; Buschhagen, Timo; Naik, Sameer; Gore, Jay; Lucht, Robert; Ihme, Matthias

2015-11-01

Fuel injection and atomization are of direct importance to the design of injector systems in aviation gas turbine engines. Primary and secondary breakup processes have significant influence on the drop-size distribution, fuel deposition, and flame stabilization, thereby directly affecting fuel conversion, combustion stability, and emission formation. The lack of predictive modeling capabilities for the reliable characterization of primary and secondary breakup mechanisms is still one of the main issues in improving injector systems. In this study, an unstructured Volume-of-Fluid method was used in conjunction with a Lagrangian-spray framework to conduct high-fidelity simulations of the breakup and atomization processes in a realistic gas turbine hybrid air blast atomizer. Results for injection with JP-8 aviation fuel are presented and compared to available experimental data. Financial support through the FAA National Jet Fuel Combustion Program is gratefully acknowledged.

Simultaneous removal of NOx and SO2 from flue gas using combined Na2SO3 assisted electrochemical reduction and direct electrochemical reduction.

PubMed

Guo, Qingbin; He, Yi; Sun, Tonghua; Wang, Yalin; Jia, Jinping

2014-07-15

A method combining Na2SO3 assisted electrochemical reduction and direct electrochemical reduction using Fe(II)(EDTA) solution was proposed to simultaneously remove NOx and SO2 from flue gas. Activated carbon was used as catalyst to accelerate the process. This new system features (a) direct conversion of NOx and SO2 to harmless N2 and SO4(2-); (b) fast regeneration of Fe(II)(EDTA); (c) minimum use of chemical reagents; and (d) recovery of the reduction by-product (Na2SO4). Fe(II)(EDTA) solution was continuously recycled and reused during entire process, and no harmful waste was generated. Approximately 99% NOx and 98% SO2 were removed under the optimal condition. The stability test showed that the system operation was reliable. Copyright © 2014 Elsevier B.V. All rights reserved.

Application of gas diffusion electrodes in bioelectrochemical syntheses and energy conversion.

PubMed

Horst, Angelika E W; Mangold, Klaus-Michael; Holtmann, Dirk

2016-02-01

Combining the advantages of biological components (e.g., reaction specificity, self-replication) and electrochemical techniques in bioelectrochemical systems offers the opportunity to develop novel efficient and sustainable processes for the production of a number of valuable products. The choice of electrode material has a great impact on the performance of bioelectrochemical systems. In addition to the redox process at the electrodes, interactions of biocatalysts with electrodes (e.g., enzyme denaturation or biofouling) need to be considered. In recent years, gas diffusion electrodes (GDEs) have proved to be very attractive electrodes for bioelectrochemical purposes. GDEs are porous electrodes, that posses a large three-phase boundary surface. At this interface, a solid catalyst supports the electrochemical reaction between gaseous and liquid phase. This mini-review discusses the application of GDEs in microbial and enzymatic fuel cells, for microbial electrolysis, in biosensors and for electroenzymatic synthesis reactions. © 2015 Wiley Periodicals, Inc.

Land-Use Change, Soil Process and Trace Gas Fluxes in the Brazilian Amazon Basin

NASA Technical Reports Server (NTRS)

Melillo, Jerry M.; Steudler, Paul A.

1997-01-01

We measured changes in key soil processes and the fluxes of CO2, CH4 and N2O associated with the conversion of tropical rainforest to pasture in Rondonia, a state in the southwest Amazon that has experienced rapid deforestation, primarily for cattle ranching, since the late 1970s. These measurements provide a comprehensive quantitative picture of the nature of surface soil element stocks, C and nutrient dynamics, and trace gas fluxes between soils and the atmosphere during the entire sequence of land-use change from the initial cutting and burning of native forest, through planting and establishment of pasture grass and ending with very old continuously-pastured land. All of our work is done in cooperation with Brazilian scientists at the Centro de Energia Nuclear na Agricultura (CENA) through an extant official bi-lateral agreement between the Marine Biological Laboratory and the University of Sao Paulo, CENA's parent institution.

A Three-Step Resolution-Reconfigurable Hazardous Multi-Gas Sensor Interface for Wireless Air-Quality Monitoring Applications.

PubMed

Choi, Subin; Park, Kyeonghwan; Lee, Seungwook; Lim, Yeongjin; Oh, Byungjoo; Chae, Hee Young; Park, Chan Sam; Shin, Heugjoo; Kim, Jae Joon

2018-03-02

This paper presents a resolution-reconfigurable wide-range resistive sensor readout interface for wireless multi-gas monitoring applications that displays results on a smartphone. Three types of sensing resolutions were selected to minimize processing power consumption, and a dual-mode front-end structure was proposed to support the detection of a variety of hazardous gases with wide range of characteristic resistance. The readout integrated circuit (ROIC) was fabricated in a 0.18 μm CMOS process to provide three reconfigurable data conversions that correspond to a low-power resistance-to-digital converter (RDC), a 12-bit successive approximation register (SAR) analog-to-digital converter (ADC), and a 16-bit delta-sigma modulator. For functional feasibility, a wireless sensor system prototype that included in-house microelectromechanical (MEMS) sensing devices and commercial device products was manufactured and experimentally verified to detect a variety of hazardous gases.

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.

Method and system for controlling a gasification or partial oxidation process

DOEpatents

Rozelle, Peter L; Der, Victor K

2015-02-10

A method and system for controlling a fuel gasification system includes optimizing a conversion of solid components in the fuel to gaseous fuel components, controlling the flux of solids entrained in the product gas through equipment downstream of the gasifier, and maximizing the overall efficiencies of processes utilizing gasification. A combination of models, when utilized together, can be integrated with existing plant control systems and operating procedures and employed to develop new control systems and operating procedures. Such an approach is further applicable to gasification systems that utilize both dry feed and slurry feed.

Potassium-chemical synthesis of 3D graphene from CO 2 and its excellent performance in HTM-free perovskite solar cells

DOE PAGES

Wei, Wei; Hu, Baoyun; Jin, Fangming; ...

2017-03-29

The conversion of greenhouse gas CO 2 into novel materials is the most promising approach to solve greenhouse gas issues. In this paper, we report for the first time the reaction of potassium with CO 2 to synthesize three-dimensional honeycomb-like structured graphene (3DHG). Furthermore, 3DHG exhibited excellent performance as a counter electrode for hole transport material (HTM)-free perovskite solar cells, leading to a power conversion efficiency of 10.06%. Finally, this work constitutes a new aspect of potassium chemistry for material synthesis from a greenhouse gas and the generation of electrical energy from sunlight.

Method of inducing surface ensembles on a metal catalyst

DOEpatents

Miller, Steven S.

1989-01-01

A method of inducing surface ensembles on a transition metal catalyst used in the conversion of a reactant gas or gas mixture, such as carbon monoxide and hydrogen into hydrocarbons (the Fischer-Tropsch reaction) is disclosed which comprises adding a Lewis base to the syngas (CO+H.sub.2) mixture before reaction takes place. The formation of surface ensembles in this manner restricts the number and types of reaction pathways which will be utilized, thus greatly narrowing the product distribution and maximizing the efficiency of the Fischer-Tropsch reaction. Similarly, amines may also be produced by the conversion of reactant gas or gases, such as nitrogen, hydrogen, or hydrocarbon constituents.

Method of inducing surface ensembles on a metal catalyst

DOEpatents

Miller, S.S.

1987-10-02

A method of inducing surface ensembles on a transition metal catalyst used in the conversion of a reactant gas or gas mixture, such as carbon monoxide and hydrogen into hydrocarbons (the Fischer-Tropsch reaction) is disclosed which comprises adding a Lewis base to the syngas (CO + H/sub 2/) mixture before reaction takes place. The formation of surface ensembles in this manner restricts the number and types of reaction pathways which will be utilized, thus greatly narrowing the product distribution and maximizing the efficiency of the Fischer-Tropsch reaction. Similarly, amines may also be produced by the conversion of reactant gas or gases, such as nitrogen, hydrogen, or hydrocarbon constituents.

The conversion of biomass to light olefins on Fe-modified ZSM-5 catalyst: Effect of pyrolysis parameters.

PubMed

Zhang, Shihong; Yang, Mingfa; Shao, Jingai; Yang, Haiping; Zeng, Kuo; Chen, Yingquan; Luo, Jun; Agblevor, Foster A; Chen, Hanping

2018-07-01

Light olefins are the key building blocks for the petrochemical industry. In this study, the effects of in-situ and ex-situ process, temperature, Fe loading, catalyst to feed ratio and gas flow rate on the olefins carbon yield and selectivity were explored. The results showed that Fe-modified ZSM-5 catalyst increased the olefins yield significantly, and the ex-situ process was much better than in-situ. With the increasing of temperature, Fe-loading amount, catalyst to feed ratio, and gas flow rate, the carbon yields of light olefins were firstly increased and further decreased. The maximum carbon yield of light olefins (6.98% C-mol) was obtained at the pyrolysis temperature of 600°C, catalyst to feed ratio of 2, gas flow rate of 100ml/min, and 3wt% Fe/ZSM-5 for cellulose. The selectivity of C 2 H 4 was more than 60% for all feedstock, and the total light olefins followed the decreasing order of cellulose, corn stalk, hemicelluloses and lignin. Copyright © 2018 Elsevier B.V. All rights reserved.

Design of an integrated fuel processor for residential PEMFCs applications

NASA Astrophysics Data System (ADS)

Seo, Yu Taek; Seo, Dong Joo; Jeong, Jin Hyeok; Yoon, Wang Lai

KIER has been developing a novel fuel processing system to provide hydrogen rich gas to residential PEMFCs system. For the effective design of a compact hydrogen production system, each unit process for steam reforming and water gas shift, has a steam generator and internal heat exchangers which are thermally and physically integrated into a single packaged hardware system. The newly designed fuel processor (prototype II) showed a thermal efficiency of 78% as a HHV basis with methane conversion of 89%. The preferential oxidation unit with two staged cascade reactors, reduces, the CO concentration to below 10 ppm without complicated temperature control hardware, which is the prerequisite CO limit for the PEMFC stack. After we achieve the initial performance of the fuel processor, partial load operation was carried out to test the performance and reliability of the fuel processor at various loads. The stability of the fuel processor was also demonstrated for three successive days with a stable composition of product gas and thermal efficiency. The CO concentration remained below 10 ppm during the test period and confirmed the stable performance of the two-stage PrOx reactors.

Process for the production of fuel gas from coal

DOEpatents

Patel, Jitendra G.; Sandstrom, William A.; Tarman, Paul B.

1982-01-01

An improved apparatus and process for the conversion of hydrocarbonaceous materials, such as coal, to more valuable gaseous products in a fluidized bed gasification reaction and efficient withdrawal of agglomerated ash from the fluidized bed is disclosed. The improvements are obtained by introducing an oxygen containing gas into the bottom of the fluidized bed through a separate conduit positioned within the center of a nozzle adapted to agglomerate and withdraw the ash from the bottom of the fluidized bed. The conduit extends above the constricted center portion of the nozzle and preferably terminates within and does not extend from the nozzle. In addition to improving ash agglomeration and withdrawal, the present invention prevents sintering and clinkering of the ash in the fluidized bed and permits the efficient recycle of fine material recovered from the product gases by contacting the fines in the fluidized bed with the oxygen as it emanates from the conduit positioned within the withdrawal nozzle. Finally, the present method of oxygen introduction permits the efficient recycle of a portion of the product gases to the reaction zone to increase the reducing properties of the hot product gas.

Green plants as solar energy converters

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

Not Available

1976-06-01

A survey covers the potential of energy production from biomass and solid wastes; various processes for the combustion of wastes, such as the co-combustion of solid waste and sewage sludge at the St. Paul/Seneca Treatment Plant Sludge Incinerator; various biological processes for the conversion of solid wastes to fuel such as the Institute of Gas Technology 400 l. digestor for the biogasification of municipal solid waste and sewage solids to a methane-rich product gas; the use of industrial wastes for fuel, such as slash and mill residues used as fuel in lumber mills; the biogasification of animal wastes by usingmore » small-scale on-site digesters to produce methane gas for cooking and lighting; energy farming methods, such as growing giant California kelp, sargassum, and plankton as suitable feedstock for the production of methane, fertilizers, and food; problems, such as the possible alteration of the reflectivity of large areas of the earth's surface by rapidly growing plants raised for biomass; and benefits such as the reduction in air, water, and land pollution associated with the use of wastes and biomass grown especially for energy.« less

Evaluation of Methods for the Determination of Black Carbon Emissions from an Aircraft Gas Turbine Engine

EPA Science Inventory

The emissions from aircraft gas turbine engines consist of nanometer size black carbon (BC) particles plus gas-phase sulfur and organic compounds which undergo gas-to-particle conversion downstream of the engine as the plume cools and dilutes. In this study, four BC measurement ...

Methane - fuel for the future

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

McGeer, P.; Durbin, E.

1982-01-01

The 20 invited papers presented at the world conference on alternative fuel entitled 'Methane - fuel for the future' form the basis of this book. Papers discuss: the availability of alternative fuels (natural gas, biomass conversion to methane, methane from coal conversion); technological adaptions for alternative fuels (e.g. natural gas fueled engines, methane and diesel engines); commercial experience with alternative fuel programs. (e.g. retailing of methane); and some national programs for alternative fuels. One paper has been abstracted separately.

Hydrogen Gas-Mediated Deoxydehydration/Hydrogenation of Sugar Acids: Catalytic Conversion of Glucarates to Adipates.

PubMed

Larson, Reed T; Samant, Andrew; Chen, Jianbin; Lee, Woojin; Bohn, Martin A; Ohlmann, Dominik M; Zuend, Stephan J; Toste, F Dean

2017-10-11

The development of a system for the operationally simple, scalable conversion of polyhydroxylated biomass into industrially relevant feedstock chemicals is described. This system includes a bimetallic Pd/Re catalyst in combination with hydrogen gas as a terminal reductant and enables the high-yielding reduction of sugar acids. This procedure has been applied to the synthesis of adipate esters, precursors for the production of Nylon-6,6, in excellent yield from biomass-derived sources.

Pyrolysis and gasification of landfilled plastic wastes with Ni-Mg-La/Al2O3 catalyst.

PubMed

Kaewpengkrow, Prangtip; Atong, Duangduen; Sricharoenchaikul, Viboon

2012-12-01

Pyrolysis and gasification processes were utilized to study the feasibility of producing fuels from landfilled plastic wastes. These wastes were converted in a gasifier at 700-900 degrees C. The equivalence ratio (ER) was varied from 0.4-0.6 with or without addition ofa Ni-Mg-La/Al2O3 catalyst. The pyrolysis and gasification of plastic wastes without catalyst resulted in relatively low H2, CO and other fuel gas products with methane as the major gaseous species. The highest lower heating value (LHV) was obtained at 800 degrees C and for an ER of 0.4, while the maximum cold gas efficiency occurred at 700 degrees C and for an ER of 0.4. The presence of the Ni-Mg-La/Al2O3 catalyst significantly enhanced H2 and CO production as well as increasing the gas energy content to 15.76-19.26 MJ/m3, which is suitable for further usage as quality fuel gas. A higher temperature resulted in more H2 and CO and other product gas yields, while char and liquid (tars) decreased. The maximum gas yield, gas calorific value and cold gas efficiency were achieved when the Ni-Mg-La/Al2O3 catalyst was used at 900 degrees C. In general, addition of prepared catalyst resulted in greater H2, CO and other light hydrocarbon yields from superior conversion of wastes to these gases. Thus, thermochemical treatment of these problematic wastes using pyrolysis and gasification processes is a very attractive alternative for sustainable waste management.

Fluidic hydrogen detector production prototype development

NASA Technical Reports Server (NTRS)

Roe, G. W.; Wright, R. E.

1976-01-01

A hydrogen gas sensor that can replace catalytic combustion sensors used to detect leaks in the liquid hydrogen transfer systems at Kennedy Space Center was developed. A fluidic sensor concept, based on the principle that the frequency of a fluidic oscillator is proportional to the square root of the molecular weight of its operating fluid, was utilized. To minimize sensitivity to pressure and temperature fluctuations, and to make the sensor specific for hydrogen, two oscillators are used. One oscillator operates on sample gas containing hydrogen, while the other operates on sample gas with the hydrogen converted to steam. The conversion is accomplished with a small catalytic converter. The frequency difference is taken, and the hydrogen concentration computed with a simple digital processing circuit. The output from the sensor is an analog signal proportional to hydrogen content. The sensor is shown to be accurate and insensitive to severe environmental disturbances. It is also specific for hydrogen, even with large helium concentrations in the sample gas.

Internal reforming of methane in solid oxide fuel cell systems

NASA Astrophysics Data System (ADS)

Peters, R.; Dahl, R.; Klüttgen, U.; Palm, C.; Stolten, D.

Internal reforming is an attractive option offering a significant cost reduction, higher efficiencies and faster load response of a solid oxide fuel cell (SOFC) power plant. However, complete internal reforming may lead to several problems which can be avoided with partial pre-reforming of natural gas. In order to achieve high total plant efficiency associated with low energy consumption and low investment costs, a process concept has been developed based on all the components of the SOFC system. In the case of anode gas recycling an internal steam circuit exists. This has the advantage that there is no need for an external steam generator and the steam concentration in the anode gas is reduced. However, anode gas recycling has to be proven by experiments in a pre-reformer and for internal reforming. The addition of carbon dioxide clearly shows a decrease in catalyst activity, while for temperatures higher than 1000 K hydrogen leads to an increase of the measured methane conversion rates.

Swarm intelligence for multi-objective optimization of synthesis gas production

NASA Astrophysics Data System (ADS)

Ganesan, T.; Vasant, P.; Elamvazuthi, I.; Ku Shaari, Ku Zilati

2012-11-01

In the chemical industry, the production of methanol, ammonia, hydrogen and higher hydrocarbons require synthesis gas (or syn gas). The main three syn gas production methods are carbon dioxide reforming (CRM), steam reforming (SRM) and partial-oxidation of methane (POM). In this work, multi-objective (MO) optimization of the combined CRM and POM was carried out. The empirical model and the MO problem formulation for this combined process were obtained from previous works. The central objectives considered in this problem are methane conversion, carbon monoxide selectivity and the hydrogen to carbon monoxide ratio. The MO nature of the problem was tackled using the Normal Boundary Intersection (NBI) method. Two techniques (Gravitational Search Algorithm (GSA) and Particle Swarm Optimization (PSO)) were then applied in conjunction with the NBI method. The performance of the two algorithms and the quality of the solutions were gauged by using two performance metrics. Comparative studies and results analysis were then carried out on the optimization results.

AMTEC powered residential furnace and auxiliary power

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

Ivanenok, J.F. III; Sievers, R.K.

1996-12-31

Residential gas furnaces normally rely on utility grid electric power to operate the fans and/or the pumps used to circulate conditioned air or water and they are thus vulnerable to interruptions of utility grid service. Experience has shown that such interruptions can occur during the heating season, and can lead to serious consequences. A gas furnace coupled to an AMTEC conversion system retains the potential to produce heat and electricity (gas lines are seldom interrupted during power outages), and can save approximately $47/heating season compared to a conventional gas furnace. The key to designing a power system is understanding, andmore » predicting, the cell performance characteristics. The three main processes that must be understood and modeled to fully characterize an AMTEC cell are the electro-chemical, sodium vapor flow, and heat transfer. This paper will show the results of the most recent attempt to model the heat transfer in a multi-tube AMTEC cell and then discusses the conceptual design of a self-powered residential furnace.« less

Hybrid gas-to-particle conversion and chemical vapor deposition for production of high-surface area films

NASA Astrophysics Data System (ADS)

Nguyen, Quynh Tan

A hybrid process, based upon gas-to-particle conversion and chemical vapor deposition, is presented as an alternative technique for producing porous films with the main advantages of solvent-free, low-substrate temperature operation. Starting from solid precursors, nanoparticles were produced in the vapor phase. Downstream of this reaction zone, these nanoparticles were collected via thermophoresis onto a cooled substrate forming a porous film. Initially, alumina (Al2O3) films were produced. Later, multi-component processing was explored by incorporating platinum (Pt) nanoparticles into the Al2O3 matrix leading to the production of Pt/Al 2O3 films by two routes: simultaneous precursor injection processing or by a layer-by-layer approach. In single component processing, the formation of nanoparticle aggregates was evident within the amorphous Al2O3 films. Aggregates, composed of these particles, are likely held together by relatively weak van der Waals forces leading to the observed poor physical cohesion. In multi-component processing, reasonable control of composition and distribution of species is possible with Pt nanoparticles appearing to be co-agglomerated with alumina. Deposited crystalline Pt nanoparticles may encourage the crystallization of the amorphous Al2O3. Finally, from chemisorption results, the produced sample appears to have potentially greater catalytic activity than a commercially available standard. A model is in development to study nanoparticle interactions with a gas and deposition occurring in stagnation flow onto the cooled horizontal substrate within the tubular reactor. Using velocity and temperature fields generated from numerical solutions to the Navier-Stokes and energy equations, particle trajectories were calculated from the summation of drag, gravitational, thermophoretic, and Brownian forces. In rectangular coordinates, cooling stage width to reactor diameter ratio, deposition stage temperature, and initial velocity were the primary parameters varied in this study. An optimum balance between thermophoretic and drag forces appears to be the key factor in obtaining high yield and surface uniformity in the films. The results also suggest that Brownian motion is not a significant contributor to deposition under conditions in this study.

Two-Organism Concept for the Conversion of Cellulosic Feedstocks to Fuel

DTIC Science & Technology

2010-08-01

economic importance as fully 1 % of the world’s energy supplies are consumed in the industrial fixation of nitrogen ( Haber - Bosch process), mostly to...mmol of non-cellular organic ammonia (most of the ammonia was presumably incorporated into cells for growth). The production of ethanol, expected to...Oxygen Gas Output from C. vulgaris Monitoring 10 2.1.6 Quantification of Organic Ammonia Produced by Cpnit-1 1 2.1.7 Quantification of Ethanol

Economic and life cycle assessments of biomass utilization for bioenergy products

DOE PAGES

Liu, Weiguo; Wang, Jingxin; Richard, Tom L.; ...

2017-05-04

A modeling process was developed to examine the economic and environmental benefits of utilizing energy crops for biofuels and bioproducts. Three energy crops (hybrid willow, switchgrass and miscanthus) that can potentially grow on marginal agricultural land or abandoned mine land in the northeastern United States were considered in the analytical process for the production of biofuels, biopower and pellet fuel. The supply chain components for both the economic analysis and life cycle modeling processes included feedstock establishment, harvest, transportation, storage, preprocessing, conversion, distribution and final usage. Sensitivity analysis was also conducted to assess the effects of energy crop yield, transportationmore » distance, conversion rate, facility capacity and internal rate of return (IRR) on the production of bioenergy products. The required selling price (RSP) ranged from $ 7.7/GJ to $ 47.9/GJ for different bioproducts. The production of biopower had the highest RSP and pellet fuel had the lowest. The results also indicated that bioenergy production using hybrid willow demonstrated lower RSP than the two perennial grass feedstocks. Pellet production presented the lowest greenhouse gas (GHG) emissions (less than 10 kg CO 2 eq per 1,000 MJ) and fossil energy consumption (less than 150 MJ per 1,000 MJ). The production of biofuel resulted in the highest GHG emissions. Sensitivity analysis indicated that IRR was the most sensitive factor to RSP and followed by conversion rate for biofuel and biopower production. As a result, conversion rate and transportation distance of feedstock presented a significant effect on environmental impacts during the production of the bioproducts.« less

Economic and life cycle assessments of biomass utilization for bioenergy products

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

Liu, Weiguo; Wang, Jingxin; Richard, Tom L.

A modeling process was developed to examine the economic and environmental benefits of utilizing energy crops for biofuels and bioproducts. Three energy crops (hybrid willow, switchgrass and miscanthus) that can potentially grow on marginal agricultural land or abandoned mine land in the northeastern United States were considered in the analytical process for the production of biofuels, biopower and pellet fuel. The supply chain components for both the economic analysis and life cycle modeling processes included feedstock establishment, harvest, transportation, storage, preprocessing, conversion, distribution and final usage. Sensitivity analysis was also conducted to assess the effects of energy crop yield, transportationmore » distance, conversion rate, facility capacity and internal rate of return (IRR) on the production of bioenergy products. The required selling price (RSP) ranged from $ 7.7/GJ to $ 47.9/GJ for different bioproducts. The production of biopower had the highest RSP and pellet fuel had the lowest. The results also indicated that bioenergy production using hybrid willow demonstrated lower RSP than the two perennial grass feedstocks. Pellet production presented the lowest greenhouse gas (GHG) emissions (less than 10 kg CO 2 eq per 1,000 MJ) and fossil energy consumption (less than 150 MJ per 1,000 MJ). The production of biofuel resulted in the highest GHG emissions. Sensitivity analysis indicated that IRR was the most sensitive factor to RSP and followed by conversion rate for biofuel and biopower production. As a result, conversion rate and transportation distance of feedstock presented a significant effect on environmental impacts during the production of the bioproducts.« less

Methane Pyrolysis and Disposing Off Resulting Carbon

NASA Technical Reports Server (NTRS)

Sharma, P. K.; Rapp, D.; Rahotgi, N. K.

1999-01-01

Sabatier/Electrolysis (S/E) is a leading process for producing methane and oxygen for application to Mars ISPP. One significant problem with this process is that it produces an excess of methane for combustion with the amount of oxygen that is produced. Therefore, one must discard roughly half of the methane to obtain the proper stoichiometric methane/oxygen mixture for ascent from Mars. This is wasteful of hydrogen, which must be brought from Earth and is difficult to transport to Mars and store on Mars. To reduced the problem of transporting hydrogen to Mars, the S/E process can be augmented by another process which reduces overall hydrogen requirement. Three conceptual approaches for doing this are (1) recover hydrogen from the excess methane produced by the S/E process, (2) convert the methane to a higher hydrocarbon or other organic with a lower H/C ratio than methane, and (3) use a separate process (such as zirconia or reverse water gas shift reaction) to produce additional oxygen, thus utilizing all the methane produced by the Sabatier process. We report our results here on recovering hydrogen from the excess methane using pyrolysis of methane. Pyrolysis has the advantage that it produces almost pure hydrogen, and any unreacted methane can pass through the S/E process reactor. It has the disadvantage that disposing of the carbon produced by pyrolysis presents difficulties. Hydrogen may be obtained from methane by pyrolysis in the temperature range 10000-12000C. The main reaction products are hydrogen and carbon, though very small amounts of higher hydrocarbons, including aromatic hydrocarbons are formed. The conversion efficiency is about 95% at 12000C. One needs to distinguish between thermodynamic equilibrium conversion and conversion limited by kinetics in a finite reactor.

Conversion of wood residues to diesel fuel

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

Kuester, J.L.

1981-01-01

The basic approach is indirect liquefaction, i.e., thermal gasification followed by catalytic liquefaction. The indirect approach results in separation of the oxygen in the biomass feedstock, i.e., oxygenated compounds do not appear in the liquid hydrocarbon fuel product. The general conversion scheme is shown. The process is capable of accepting a wide variety of feedstocks. Potential products include medium quality gas, normal propanol, paraffinic fuel and/or high octane gasoline. A flow diagram of the continuous laboratory unit is shown. A fluidized bed pyrolysis system is used for gasification. Capacity is about 10 lbs/h of feedstock. The pyrolyzer can be fluidizedmore » with recycle pyrolysis gas, steam or recycle liquefaction system off gas or some combination thereof. Tars are removed in a wet scrubber. Unseparated pyrolysis gases are utilized as feed to a modified Fischer-Tropsch reactor. The liquid condensate from the reactor consists of a normal propanol-water phase and a paraffinic hydrocarbon phase. The reactor can be operated to optimize for either product. If a high octane gasoline is desired, the paraffinic fuel is passed through a conventional catalytic reformer. The normal propanol could be used as a fuel extender if blended with the hydrocarbon fuel products. Off gases from the downstream reactors are of high quality due to the accumulation of low molecular weight paraffins.« less

High-Voltage, High-Power Gaseous Electronics Switch For Electric Grid Power Conversion

NASA Astrophysics Data System (ADS)

Sommerer, Timothy J.

2014-05-01

We are developing a high-voltage, high-power gas switch for use in low-cost power conversion terminals on the electric power grid. Direct-current (dc) power transmission has many advantages over alternating current (ac) transmission, but at present the high cost of ac-dc power interconversion limits the use of dc. The gas switch we are developing conducts current through a magnetized cold cathode plasma in hydrogen or helium to reach practical current densities > 1 A/cm2. Thermal and sputter damage of the cathode by the incident ion flux is a major technical risk, and is being addressed through use of a ``self-healing'' liquid metal cathode (eg, gallium). Plasma conditions and cathode sputtering loss are estimated by analyzing plasma spectral emission. A particle-in-cell plasma model is used to understand various aspects of switch operation, including the conduction phase (where plasma densities can exceed 1013 cm-3), the switch-open phase (where the high-voltage must be held against gas breakdown on the left side of Paschen's curve), and the switching transitions (especially the opening process, which is initiated by forming an ion-matrix sheath adjacent to a control grid). The information, data, or work presented herein was funded in part by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000298.

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.

Alternative Fuels Data Center

Science.gov Websites

vehicles altered to operate on propane, natural gas, methane gas, ethanol, or electricity are classified as information about vehicle conversion certification requirements, see the Alternative Fuels Data Center's

Carbothermal Processing of Lunar Regolith Using Methane

NASA Technical Reports Server (NTRS)

Balasubramaniam, R.; Hegde, U.; Gokoglu, S.

2009-01-01

The processing of lunar regolith for the production of oxygen is a key component of the In-Situ Resource Utilization plans currently being developed by NASA. Among various candidate processes, the modeling of oxygen production by hydrogen reduction, molten salt electrolysis, and carbothermal processing are presently being pursued. In the carbothermal process, a portion of the surface of the regolith in a container is heated by exposure to a heat source such as a laser beam or a concentrated solar heat flux, so that a small zone of molten regolith is established. The molten zone is surrounded by solid regolith particles that are poor conductors of heat. A continuous flow of methane is maintained over the molten regolith zone. Our model is based on a mechanism where methane pyrolyzes when it comes in contact with the surface of the hot molten regolith to form solid carbon and hydrogen gas. Carbon is deposited on the surface of the melt, and hydrogen is released into the gas stream above the melt surface. We assume that the deposited carbon mixes in the molten regolith and reacts with metal oxides in a reduction reaction by which gaseous carbon monoxide is liberated. Carbon monoxide bubbles through the melt and is released into the gas stream. Oxygen is produced subsequently by (catalytically) processing the carbon monoxide downstream. In this paper, we discuss the development of a chemical conversion model of the carbothermal process to predict the rate of production of carbon monoxide.

Carbothermal Processing of Lunar Regolith Using Methane

NASA Technical Reports Server (NTRS)

Balasubramaniam, R.; Hegde, U.; Gokoglu, S.

2008-01-01

The processing of lunar regolith for the production of oxygen is a key component of the In-Situ Resource Utilization plans currently being developed by NASA. Among various candidate processes, the modeling of oxygen production by hydrogen reduction, molten salt electrolysis, and carbothermal processing are presently being pursued. In the carbothermal process, a portion of the surface of the regolith in a container is heated by exposure to a heat source such as a laser beam or a concentrated solar heat flux, so that a small zone of molten regolith is established. The molten zone is surrounded by solid regolith particles that are poor conductors of heat. A continuous flow of methane is maintained over the molten regolith zone. Our model is based on a mechanism where methane pyrolyzes when it comes in contact with the surface of the hot molten regolith to form solid carbon and hydrogen gas. Carbon is deposited on the surface of the melt, and hydrogen is released into the gas stream above the melt surface. We assume that the deposited carbon mixes in the molten regolith and reacts with metal oxides in a reduction reaction by which gaseous carbon monoxide is liberated. Carbon monoxide bubbles through the melt and is released into the gas stream. Oxygen is produced subsequently by (catalytically) processing the carbon monoxide downstream. In this paper, we discuss the development of a chemical conversion model of the carbothermal process to predict the rate of production of carbon monoxide.

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.

Analysis of Hydrogen Generation through Thermochemical Gasification of Coconut Shell Using Thermodynamic Equilibrium Model Considering Char and Tar

PubMed Central

Rupesh, Shanmughom; Muraleedharan, Chandrasekharan; Arun, Palatel

2014-01-01

This work investigates the potential of coconut shell for air-steam gasification using thermodynamic equilibrium model. A thermodynamic equilibrium model considering tar and realistic char conversion was developed using MATLAB software to predict the product gas composition. After comparing it with experimental results the prediction capability of the model is enhanced by multiplying equilibrium constants with suitable coefficients. The modified model is used to study the effect of key process parameters like temperature, steam to biomass ratio, and equivalence ratio on product gas yield, composition, and heating value of syngas along with gasification efficiency. For a steam to biomass ratio of unity, the maximum mole fraction of hydrogen in the product gas is found to be 36.14% with a lower heating value of 7.49 MJ/Nm3 at a gasification temperature of 1500 K and equivalence ratio of 0.15. PMID:27433487

Analysis of Hydrogen Generation through Thermochemical Gasification of Coconut Shell Using Thermodynamic Equilibrium Model Considering Char and Tar.

PubMed

Rupesh, Shanmughom; Muraleedharan, Chandrasekharan; Arun, Palatel

2014-01-01

This work investigates the potential of coconut shell for air-steam gasification using thermodynamic equilibrium model. A thermodynamic equilibrium model considering tar and realistic char conversion was developed using MATLAB software to predict the product gas composition. After comparing it with experimental results the prediction capability of the model is enhanced by multiplying equilibrium constants with suitable coefficients. The modified model is used to study the effect of key process parameters like temperature, steam to biomass ratio, and equivalence ratio on product gas yield, composition, and heating value of syngas along with gasification efficiency. For a steam to biomass ratio of unity, the maximum mole fraction of hydrogen in the product gas is found to be 36.14% with a lower heating value of 7.49 MJ/Nm(3) at a gasification temperature of 1500 K and equivalence ratio of 0.15.

A review on the performance and modelling of proton exchange membrane fuel cells

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

Boucetta, A., E-mail: abirboucetta@yahoo.fr; Ghodbane, H., E-mail: h.ghodbane@mselab.org; Bahri, M., E-mail: m.bahri@mselab.org

2016-07-25

Proton Exchange Membrane Fuel Cells (PEMFC), are energy efficient and environmentally friendly alternative to conventional energy conversion for various applications in stationary power plants, portable power device and transportation. PEM fuel cells provide low operating temperature and high-energy efficiency with near zero emission. A PEM fuel cell is a multiple distinct parts device and a series of mass, energy, transport through gas channels, electric current transport through membrane electrode assembly and electrochemical reactions at the triple-phase boundaries. These processes play a decisive role in determining the performance of the Fuel cell, so that studies on the phenomena of gas flowsmore » and the performance modelling are made deeply. This paper gives a comprehensive overview of the state of the art on the Study of the phenomena of gas flow and performance modelling of PEMFC.« less

Microwave plasma generation of hydrogen atoms for rocket propulsion

NASA Technical Reports Server (NTRS)

Chapman, R.; Filpus, J.; Morin, T.; Snellenberger, R.; Asmussen, J.; Hawley, M.; Kerber, R.

1981-01-01

A flow microwave plasma reaction system is used to study the conversion of hydrogen to hydrogen atoms as a function of pressure, power density, cavity tuning, cavity mode, and time in the plasma zone. Hydrogen atom concentration is measured down-stream from the plasma by NOCl titration. Extensive modeling of the plasma and recombination zones is performed with the plasma zone treated as a backmix reaction system and the recombination zone treated as a plug flow. The thermodynamics and kinetics of the recombination process are examined in detail to provide an understanding of the conversion of recombination energy to gas kinetic energy. It is found that cavity tuning, discharge stability, and optimum power coupling are critically dependent on the system pressure, but nearly independent of the flow rate.

Denitrifying sulfide removal process on high-salinity wastewaters in the presence of Halomonas sp.

PubMed

Liu, Chunshuang; Zhao, Dongfeng; Ma, Wenjuan; Guo, Yadong; Wang, Aijie; Wang, Qilin; Lee, Duu-Jong

2016-02-01

Biological conversion of sulfide, acetate, and nitrate to, respectively, elemental sulfur (S(0)), carbon dioxide, and nitrogen-containing gas (such as N2) at NaCl concentration of 35-70 g/L was achieved in an expanded granular sludge bed (EGSB) reactor. A C/N ratio of 1:1 was noted to achieve high sulfide removal and S(0) conversion rate at high salinity. The extracellular polymeric substance (EPS) quantities were increased with NaCl concentration, being 11.4-mg/g volatile-suspended solids at 70 mg/L NaCl. The denitrifying sulfide removal (DSR) consortium incorporated Thauera sp. and Halomonas sp. as the heterotrophs and Azoarcus sp. being the autotrophs at high salinity condition. Halomonas sp. correlates with the enhanced DSR performance at high salinity.

Methods and apparatus for carbon dioxide removal from a fluid stream

DOEpatents

Wei, Wei; Ruud, James Anthony; Ku, Anthony Yu-Chung; Ramaswamy, Vidya; Liu, Ke

2010-01-19

An apparatus for producing hydrogen gas wherein the apparatus includes a reactor. In one embodiment, the reactor includes at least two conversion-removal portions. Each conversion-removal portion comprises a catalyst section configured to convert CO in the stream to CO.sub.2 and a membrane section located downstream of and in flow communication with the catalyst section. The membrane section is configured to selectively remove the CO.sub.2 from the stream and to be in flow communication with a sweep gas.

Thermal decomposition of selected chlorinated hydrocarbons during gas combustion in fluidized bed

PubMed Central

2013-01-01

Background The process of thermal decomposition of dichloromethane (DCM) and chlorobenzene (MCB) during the combustion in an inert, bubbling fluidized bed, supported by LPG as auxiliary fuel, have been studied. The concentration profiles of C6H5CI, CH2Cl2, CO2, CO, NOx, COCl2, CHCl3, CH3Cl, C2H2, C6H6, CH4 in the flue gases were specified versus mean bed temperature. Results The role of preheating of gaseous mixture in fluidized bed prior to its ignition inside bubbles was identified as important factor for increase the degree of conversion of DCM and MCB in low bed temperature, in comparison to similar process in the tubular reactor. Conclusions Taking into account possible combustion mechanisms, it was identified that autoignition in bubbles rather than flame propagation between bubbles is needed to achieve complete destruction of DCM and MCB. These condition occurs above 900°C causing the degree of conversion of chlorine compounds of 92-100%. PMID:23289764

Thermal decomposition of selected chlorinated hydrocarbons during gas combustion in fluidized bed.

PubMed

Olek, Malgorzata; Baron, Jerzy; Zukowski, Witold

2013-01-06

The process of thermal decomposition of dichloromethane (DCM) and chlorobenzene (MCB) during the combustion in an inert, bubbling fluidized bed, supported by LPG as auxiliary fuel, have been studied. The concentration profiles of C6H5CI, CH2Cl2, CO2, CO, NOx, COCl2, CHCl3, CH3Cl, C2H2, C6H6, CH4 in the flue gases were specified versus mean bed temperature. The role of preheating of gaseous mixture in fluidized bed prior to its ignition inside bubbles was identified as important factor for increase the degree of conversion of DCM and MCB in low bed temperature, in comparison to similar process in the tubular reactor. Taking into account possible combustion mechanisms, it was identified that autoignition in bubbles rather than flame propagation between bubbles is needed to achieve complete destruction of DCM and MCB. These condition occurs above 900°C causing the degree of conversion of chlorine compounds of 92-100%.

Denitrifying sulfide removal process on high-salinity wastewaters.

PubMed

Liu, Chunshuang; Zhao, Chaocheng; Wang, Aijie; Guo, Yadong; Lee, Duu-Jong

2015-08-01

Denitrifying sulfide removal (DSR) process comprising both heterotrophic and autotrophic denitrifiers can simultaneously convert nitrate, sulfide, and acetate into nitrogen gas, elemental sulfur (S(0)), and carbon dioxide, respectively. Sulfide- and nitrate-laden wastewaters at 2-35 g/L NaCl were treated by DSR process. A C/N ratio of 3:1 was proposed to maintain high S(0) conversion rate. The granular sludge with a compact structure and smooth outer surface was formed. The microbial communities of DSR consortium via high-throughput sequencing method suggested that salinity shifts the predominating heterotrophic denitrifiers at <10 g/L NaCl to autotrophic denitrifiers at >10 g/L NaCl.

Assessment of institutional barriers to the use of natural gas fuel in automotive vehicle fleets

NASA Technical Reports Server (NTRS)

Jablonski, J.; Lent, L.; Lawrence, M.; White, L.

1983-01-01

Institutional barriers to the use of natural gas as a fuel for motor vehicle fleets were identified. Recommendations for barrier removal were developed. Eight types of institutional barriers were assessed: (1) lack of a national standard for the safe design and certification of natural gas vehicles and refueling stations; (2) excessively conservative or misapplied state and local regulations, including bridge and tunnel restrictions, restrictions on types of vehicles that may be fueled by natural gas, zoning regulations that prohibit operation of refueling stations, parking restrictions, application of LPG standards to LNG vehicles, and unintentionally unsafe vehicle or refueling station requirements; (3) need for clarification of EPA's tampering enforcement policy; (4) the U.S. hydrocarbon standard; (5) uncertainty concerning state utility commission jurisdiction; (6) sale for resale prohibitions imposed by natural gas utility companies or state utility commissions; (7) uncertainty of the effects of conversions to natural gas on vehicle manufactures warranties; and (8) need for a natural gas to gasoline equivalent units conversion factor for use in calculation of state road use taxes.

Research on solvent-refined coal. Quarterly technical progress report, April 1, 1981-June 30, 1981

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

Not Available

1981-10-01

This report describes progress on the Research on Solvent Refined Coal project by The Pittsburg and Midway Coal Mining Co.'s Merriam Laboratory during the second quarter of 1981. Alexander Mine coal was evaluated as a feedstock for major liquefaction facilities and had a yield structure similar to other reactive Pittsburgh seam coals at standard SRC II conditions. Two lots of coal from the Ireland Mine (Pittsburgh seam) were found to be of nearly the same composition and produced essentially the same yields. Two experiments in which coal-derived nonvolatile organic matter was processed without fresh coal feed indicate constant rates ofmore » conversion of SRC to oil and gas. Insoluble organic matter (IOM) remained unconverted. The naphtha and middle distillate products from the deep conversion contained less sulfur but more nitrogen than those from conventional SRC II processing. Encouraging results were obtained when a very small amount of iron oxide dispersed on alumina was added to Kaiparowits coal which cannot be processed at normal SRC II conditions without added catalyst. Subbituminous coals from the McKinley and Edna Mines were processed successfully with added pyrite but would not run when the added catalyst was removed.« less

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

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.

Conversion of Nuclear Waste into Nuclear Waste Glass: Experimental Investigation and Mathematical Modeling

DOE PAGES

Hrma, Pavel

2014-12-18

The melter feed, slurry, or calcine charged on the top of a pool of molten glass forms a floating layer of reacting material called the cold cap. Between the cold-cap top, which is covered with boiling slurry, and its bottom, where bubbles separate it from molten glass, the temperature changes by up to 1000 K. The processes that occur over this temperature interval within the cold cap include liberation of gases, conduction and consumption of heat, dissolution of quartz particles, formation and dissolution of intermediate crystalline phases, and generation of foam and gas cavities. These processes have been investigated usingmore » thermal analyses, optical and electronic microscopies, x-ray diffraction, as well as other techniques. Properties of the reacting feed, such as heat conductivity and density, were measured as functions of temperature. Investigating the structure of quenched cold caps produced in a laboratory-scale melter complemented the crucible studies. The cold cap consists of two main layers. The top layer contains solid particles dissolving in the glass-forming melt and open pores through which gases are escaping. The bottom layer contains bubbly melt or foam where bubbles coalesce into larger cavities that move sideways and release the gas to the atmosphere. The feed-to-glass conversion became sufficiently understood for representing the cold-cap processes via mathematical models. These models, which comprise heat transfer, mass transfer, and reaction kinetics models, have been developed with the final goal to relate feed parameters to the rate of glass melting.« less

Laboratory Production of Biofuels and Biochemicals from a Rapeseed Oil through Catalytic Cracking Conversion.

PubMed

Ng, Siauw H; Shi, Yu; Heshka, Nicole E; Zhang, Yi; Little, Edward

2016-09-02

The work is based on a reported study which investigates the processability of canola oil (bio-feed) in the presence of bitumen-derived heavy gas oil (HGO) for production of transportation fuels through a fluid catalytic cracking (FCC) route. Cracking experiments are performed with a fully automated reaction unit at a fixed weight hourly space velocity (WHSV) of 8 hr(-1), 490-530 °C, and catalyst/oil ratios of 4-12 g/g. When a feed is in contact with catalyst in the fluid-bed reactor, cracking takes place generating gaseous, liquid, and solid products. The vapor produced is condensed and collected in a liquid receiver at -15 °C. The non-condensable effluent is first directed to a vessel and is sent, after homogenization, to an on-line gas chromatograph (GC) for refinery gas analysis. The coke deposited on the catalyst is determined in situ by burning the spent catalyst in air at high temperatures. Levels of CO2 are measured quantitatively via an infrared (IR) cell, and are converted to coke yield. Liquid samples in the receivers are analyzed by GC for simulated distillation to determine the amounts in different boiling ranges, i.e., IBP-221 °C (gasoline), 221-343 °C (light cycle oil), and 343 °C+ (heavy cycle oil). Cracking of a feed containing canola oil generates water, which appears at the bottom of a liquid receiver and on its inner wall. Recovery of water on the wall is achieved through washing with methanol followed by Karl Fischer titration for water content. Basic results reported include conversion (the portion of the feed converted to gas and liquid product with a boiling point below 221 °C, coke, and water, if present) and yields of dry gas (H2-C2's, CO, and CO2), liquefied petroleum gas (C3-C4), gasoline, light cycle oil, heavy cycle oil, coke, and water, if present.

Gas Foil Bearing Misalignment and Unbalance Effects

NASA Technical Reports Server (NTRS)

Howard, Samuel A.

2008-01-01

The effects of misalignment and unbalance on gas foil bearings are presented. The future of U.S. space exploration includes plans to conduct science missions aboard space vehicles, return humans to the Moon, and place humans on Mars. All of these endeavors are of long duration, and require high amounts of electrical power for propulsion, life support, mission operations, etc. One potential source of electrical power of sufficient magnitude and duration is a nuclear-fission-based system. The system architecture would consist of a nuclear reactor heat source with the resulting thermal energy converted to electrical energy through a dynamic power conversion and heat rejection system. Various types of power conversion systems can be utilized, but the Closed Brayton Cycle (CBC) turboalternator is one of the leading candidates. In the CBC, an inert gas heated by the reactor drives a turboalternator, rejects excess heat to space through a heat exchanger, and returns to the reactor in a closed loop configuration. The use of the CBC for space power and propulsion is described in more detail in the literature (Mason, 2003). In the CBC system just described, the process fluid is a high pressure inert gas such as argon, krypton, or a helium-xenon mixture. Due to the closed loop nature of the system and the associated potential for damage to components in the system, contamination of the working fluid is intolerable. Since a potential source of contamination is the lubricant used in conventional turbomachinery bearings, Gas Foil Bearings (GFB) have high potential for the rotor support system. GFBs are compliant, hydrodynamic journal and thrust bearings that use a gas, such as the CBC working fluid, as their lubricant. Thus, GFBs eliminate the possibility of contamination due to lubricant leaks into the closed loop system. Gas foil bearings are currently used in many commercial applications, both terrestrial and aerospace. Aircraft Air Cycle Machines (ACMs) and ground-based microturbines have demonstrated histories of successful long-term operation using GFBs (Heshmat et al., 2000). Small aircraft propulsion engines, helicopter gas turbines, and high-speed electric motors are potential future applications.

Methods and apparatus for using gas and liquid phase cathodic depolarizers

NASA Technical Reports Server (NTRS)

Murphy, Oliver J. (Inventor); Hitchens, G. Duncan (Inventor)

1998-01-01

The invention provides methods for using gas and liquid phase cathodic depolarizers in an electrochemical cell having a cation exchange membrane in intimate contact with the anode and cathode. The electrochemical conversion of cathodic depolarizers at the cathode lowers the cell potential necessary to achieve a desired electrochemical conversion, such as ozone evolution, at the anode. When gaseous cathodic depolarizers, such as oxygen, are used, a gas diffusion cathode having the cation exchange membrane bonded thereto is preferred. When liquid phase cathodic depolarizers are used, the cathode may be a flow-by electrode, flow-through electrode, packed-bed electrode or a fluidized-bed electrode in intimate contact with the cation exchange membrane.

THE MOLECULAR GAS DENSITY IN GALAXY CENTERS AND HOW IT CONNECTS TO BULGES

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

Fisher, David B.; Bolatto, Alberto; Drory, Niv

2013-02-20

In this paper we present gas density, star formation rate (SFR), stellar masses, and bulge-disk decompositions for a sample of 60 galaxies. Our sample is the combined sample of the BIMA SONG, CARMA STING, and PdBI NUGA surveys. We study the effect of using CO-to-H{sub 2} conversion factors that depend on the CO surface brightness, and also that of correcting SFRs for diffuse emission from old stellar populations. We estimate that SFRs in bulges are typically lower by 20% when correcting for diffuse emission. Using the surface brightness dependent conversion factor, we find that over half of the galaxies inmore » our sample have {Sigma}{sub mol} > 100 M {sub Sun} pc{sup -2}. Though our sample is not complete in any sense, our results are enough to rule out the assumption that bulges are uniformly gas-poor systems. We find a trend between gas density of bulges and bulge Sersic index; bulges with lower Sersic index have higher gas density. Those bulges with low Sersic index (pseudobulges) have gas fractions that are similar to that of disks. Conversely, the typical molecular gas fraction in classical bulges is more similar to that of an elliptical galaxy. We also find that there is a strong correlation between bulges with the highest gas surface density and the galaxy being barred. However, we also find that classical bulges with low gas surface density can be barred as well. Our results suggest that understanding the connection between the central surface density of gas in disk galaxies and the presence of bars should also take into account the total gas content of the galaxy. Finally, we show that when using the corrected SFRs and gas densities, the correlation between SFR surface density and gas surface density of bulges is similar to that of disks. This implies that at the scale of the bulges the timescale for converting gas into stars is comparable to those results found in disks.« less

Catalytic Gas-Phase Glycerol Processing over SiO2-, Cu-, Ni- and Fe- Supported Au Nanoparticles

PubMed Central

Kapkowski, Maciej; Siudyga, Tomasz; Sitko, Rafal; Lelątko, Józef; Szade, Jacek; Balin, Katarzyna; Klimontko, Joanna; Bartczak, Piotr; Polanski, Jaroslaw

2015-01-01

In this study, we investigated different metal pairings of Au nanoparticles (NPs) as potential catalysts for glycerol dehydration for the first time. All of the systems preferred the formation of hydroxyacetone (HYNE). Although the bimetallics that were tested, i.e., Au NPs supported on Ni, Fe and Cu appeared to be more active than the Au/SiO2 system, only Cu supported Au NPs gave high conversion (ca. 63%) and selectivity (ca. 70%) to HYNE. PMID:26580400

Offshore Installations and Their Relevance to the Coast Guard through the Next Twenty-Five Years. Volume II. Detailed Forecasts.

DTIC Science & Technology

1980-11-01

Deposits Red Clay/ooze Argonite deposits Manganese Nodules Minerals susceptible to gas/liquid conversion Salt Potash Minerals from Icebergs 1-7 Figure 1-2...in general, and from the arctic and antartic regions in particular; o Increased safety and security on offshore structures exposed to hazardous...Minerals present as or which may be converted Salt to liquids or gases Potash Minerals from icebergs BACKGROUND In many respects, particularly in processing

Catalytic Properties of Surfaces Sites on Metal Oxides and Their Characterization by X-Ray Photoelectron Spectroscopy

DTIC Science & Technology

1974-01-01

gas now supplies one third of our 9 national energy needs and its use is the fastest growing of all fossil fuels , conversion of coal to...the possibilities of profiling oxidation states and to gain further insight into the mechanism of the bombarding process . (2) Application of ESCA to...the surface sites—which will be measured using x-ray photoelectron spectroscopy. This technique has general applicability to a large atttibM of

A feasibility study on the bioconversion of CO2 and H2 to biomethane by gas sparging through polymeric membranes.

PubMed

Díaz, I; Pérez, C; Alfaro, N; Fdz-Polanco, F

2015-06-01

In this study, the potential of a pilot hollow-fiber membrane bioreactor for the conversion of H2 and CO2 to CH4 was evaluated. The system transformed 95% of H2 and CO2 fed at a maximum loading rate of 40.2 [Formula: see text] and produced 0.22m(3) of CH4 per m(3) of H2 fed at thermophilic conditions. H2 mass transfer to the liquid phase was identified as the limiting step for the conversion, and kLa values of 430h(-1) were reached in the bioreactor by sparging gas through the membrane module. A simulation showed that the bioreactor could upgrade biogas at a rate of 25m(3)/mR(3)d, increasing the CH4 concentration from 60 to 95%v. This proof-of-concept study verified that gas sparging through a membrane module can efficiently transfer H2 from gas to liquid phase and that the conversion of H2 and CO2 to biomethane is feasible on a pilot scale at noteworthy load rates. Copyright © 2015 Elsevier Ltd. All rights reserved.

Energy-Efficient Routes for the Production of Gasoline from Biogas and Pyrolysis Oil-Process Design and Life-Cycle Assessment.

PubMed

Sundaram, Smitha; Kolb, Gunther; Hessel, Volker; Wang, Qi

2017-03-29

Two novel routes for the production of gasoline from pyrolysis oil (from timber pine) and biogas (from ley grass) are simulated, followed by a cradle-to-gate life-cycle assessment of the two production routes. The main aim of this work is to conduct a holistic evaluation of the proposed routes and benchmark them against the conventional route of producing gasoline from natural gas. A previously commercialized method of synthesizing gasoline involves conversion of natural gas to syngas, which is further converted to methanol, and then as a last step, the methanol is converted to gasoline. In the new proposed routes, the syngas production step is different; syngas is produced from a mixture of pyrolysis oil and biogas in the following two ways: (i) autothermal reforming of pyrolysis oil and biogas, in which there are two reactions in one reactor (ATR) and (ii) steam reforming of pyrolysis oil and catalytic partial oxidation of biogas, in which there are separated but thermally coupled reactions and reactors (CR). The other two steps to produce methanol from syngas, and gasoline from methanol, remain the same. The purpose of this simulation is to have an ex-ante comparison of the performance of the new routes against a reference, in terms of energy and sustainability. Thus, at this stage of simulations, nonrigorous, equilibrium-based models have been used for reactors, which will give the best case conversions for each step. For the conventional production route, conversion and yield data available in the literature have been used, wherever available.The results of the process design showed that the second method (separate, but thermally coupled reforming) has a carbon efficiency of 0.53, compared to the conventional route (0.48), as well as the first route (0.40). The life-cycle assessment results revealed that the newly proposed processes have a clear advantage over the conventional process in some categories, particularly the global warming potential and primary energy demand; but there are also some in which the conventional route fares better, such as the human toxicity potential and the categories related to land-use change such as biotic production potential and the groundwater resistance indicator. The results confirmed that even though using biomass such as timber pine as raw material does result in reduced greenhouse gas emissions, the activities associated with biomass, such as cultivation and harvesting, contribute to the environmental footprint, particularly the land use change categories. This gives an impetus to investigate the potential of agricultural, forest, or even food waste, which would be likely to have a substantially lower impact on the environment. Moreover, it could be seen that the source of electricity used in the process has a major impact on the environmental performance.

SYSTEM FOR CONVERSION OF UF$sub 4$ TO UF$sub 6$

DOEpatents

Brater, D.G.; Pike, J.W.

1958-12-01

Method and apparatus are presented for rapid and complete conversion of solid, powdered uranium tetrafiuorlde to uranlum hexafluorlde by treating the UF/ sub 4/ with fluorine gas at a temperature of about 800 icient laborato C.

A solar simulator-pumped gas laser for the direct conversion of solar energy

NASA Technical Reports Server (NTRS)

Weaver, W. R.; Lee, J. H.

1981-01-01

Most proposed space power systems are comprised of three general stages, including the collection of the solar radiation, the conversion to a useful form, and the transmission to a receiver. The solar-pumped laser, however, effectively eliminates the middle stage and offers direct photon-to-photon conversion. The laser is especially suited for space-to-space power transmission and communication because of minimal beam spread, low power loss over large distances, and extreme energy densities. A description is presented of the first gas laser pumped by a solar simulator that is scalable to high power levels. The lasant is an iodide C3F7I that as a laser-fusion driver has produced terawatt peak power levels.

Carbon Debt of CRP Lands Converted to Annual and Perennial Bioenergy Crops

NASA Astrophysics Data System (ADS)

Abraha, M.; Gelfand, I.; Hamilton, S. K.; Chen, J.; Robertson, G. P.

2017-12-01

The net greenhouse gas fluxes of an ecosystem are directly influenced by land use conversions. In the USA, 5 Mha of grassland in the Conservation Reserve Program (CRP) have been converted to agricultural production in response to higher demand for corn grain biofuel. The global warming impact (GWI) of these biofuel crops can remain positive for many years following the conversions until the "carbon debt" incurred upon conversion is repaid. Model estimates suggest that 340-351 ×106 Mt of carbon dioxide equivalents (CO2eq) would be released to the atmosphere after the conversions. These estimates, while highly uncertain, appear to have payback times of decades or even centuries. In a field experiment conducted from 2009-16, we converted CRP grassland and conventionally-tilled agricultural (AGR) land to grain (corn) and cellulosic (switchgrass and restored prairie) biofuel feedstocks. We conducted life cycle analysis (LCA) on all converted lands by accounting for greenhouse gas fluxes related to farming operations, agronomic inputs, and soil-atmosphere greenhouse gas exchanges. We found that cumulative carbon debt for the conversion on former CRP grasslands over the 8 years is -295, 652 and 7661 gCO2eq m-2 for switchgrass, restored prairie and corn, respectively, where a positive debt indicates net emissions to the atmosphere. These indicate that the switchgrass field repaid its carbon debt in the 8th year following conversion; and the restored prairie field will likely repay its carbon debt in the next year. The corn field, however, is projected to pay its carbon debt in another 250 years. The same biofuel crops established on former AGR lands became net CO2eq sinks within two years following the conversion. Our findings indicate that the GWI estimates and the time needed to repay CO2eq debt due to conversion of grasslands to bioenergy crops is underestimated by current models.

Catalytic conversion of biomass-derived ethanol to liquid hydrocarbon blend-stock: Effect of light gas recirculation

DOE PAGES

Li, Zhenglong; Lepore, Andrew W.; Davison, Brian H.; ...

2016-01-01

Here, we describe a light gas recirculation (LGR) method to increase the liquid hydrocarbon yield with reduced aromatic content from catalytic conversion of ethanol to hydrocarbons. The previous liquid hydrocarbon yield is ~40% from one-pass ethanol conversion over V-ZSM-5 at 350 C and atmospheric pressure where the remaining ~60% yield is light gas hydrocarbons. In comparison, the liquid hydrocarbon yield increases to 80% when a simulated light gas hydrocarbon stream is co-fed at a rate of 0.053 mol g-1 h-1 with ethanol due to the conversion of most of the light olefins. The LGR also significantly improves the quality ofmore » the liquid hydrocarbon blend-stock by reducing aromatic content and overall benzene concentration. For 0.027 mol g-1 h-1 light gas mixture co-feeding, the average aromatic content in liquid hydrocarbons is 51.5% compared with 62.5% aromatic content in ethanol only experiment. Average benzene concentration decreases from 3.75% to 1.5% which is highly desirable since EPA limits benzene concentration in gasoline to 0.62%. As a result of low benzene concentration, the blend-wall for ethanol derived liquid hydrocarbons changes from ~18% to 43%. The remaining light paraffins and olefins can be further converted to valuable BTX products (94% BTX in the liquid) over Ga-ZSM-5 at 500 C. Thus, the LGR is an effective approach to convert ethanol to liquid hydrocarbons with higher liquid yield and low aromatic content, especially low benzene concentration, which could be blended with gasoline in a much higher ratio than ethanol or ethanol derived hydrocarbon blend-stock.« less

Catalytic conversion of biomass-derived ethanol to liquid hydrocarbon blend-stock: Effect of light gas recirculation

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

Li, Zhenglong; Lepore, Andrew W.; Davison, Brian H.

Here, we describe a light gas recirculation (LGR) method to increase the liquid hydrocarbon yield with reduced aromatic content from catalytic conversion of ethanol to hydrocarbons. The previous liquid hydrocarbon yield is ~40% from one-pass ethanol conversion over V-ZSM-5 at 350 C and atmospheric pressure where the remaining ~60% yield is light gas hydrocarbons. In comparison, the liquid hydrocarbon yield increases to 80% when a simulated light gas hydrocarbon stream is co-fed at a rate of 0.053 mol g-1 h-1 with ethanol due to the conversion of most of the light olefins. The LGR also significantly improves the quality ofmore » the liquid hydrocarbon blend-stock by reducing aromatic content and overall benzene concentration. For 0.027 mol g-1 h-1 light gas mixture co-feeding, the average aromatic content in liquid hydrocarbons is 51.5% compared with 62.5% aromatic content in ethanol only experiment. Average benzene concentration decreases from 3.75% to 1.5% which is highly desirable since EPA limits benzene concentration in gasoline to 0.62%. As a result of low benzene concentration, the blend-wall for ethanol derived liquid hydrocarbons changes from ~18% to 43%. The remaining light paraffins and olefins can be further converted to valuable BTX products (94% BTX in the liquid) over Ga-ZSM-5 at 500 C. Thus, the LGR is an effective approach to convert ethanol to liquid hydrocarbons with higher liquid yield and low aromatic content, especially low benzene concentration, which could be blended with gasoline in a much higher ratio than ethanol or ethanol derived hydrocarbon blend-stock.« less

Exhaustive Conversion of Inorganic Nitrogen to Nitrogen Gas Based on a Photoelectro-Chlorine Cycle Reaction and a Highly Selective Nitrogen Gas Generation Cathode.

PubMed

Zhang, Yan; Li, Jinhua; Bai, Jing; Shen, Zhaoxi; Li, Linsen; Xia, Ligang; Chen, Shuai; Zhou, Baoxue

2018-02-06

A novel method for the exhaustive conversion of inorganic nitrogen to nitrogen gas is proposed in this paper. The key properties of the system design included an exhaustive photoelectrochemical cycle reaction in the presence of Cl - , in which Cl· generated from oxidation of Cl - by photoholes selectively converted NH 4 + to nitrogen gas and some NO 3 - or NO 2 - . The NO 3 - or NO 2 - was finally reduced to nitrogen gas on a highly selective Pd-Cu-modified Ni foam (Pd-Cu/NF) cathode to achieve exhaustive conversion of inorganic nitrogen to nitrogen gas. The results indicated total nitrogen removal efficiencies of 30 mg L -1 inorganic nitrogen (NO 3 - , NH 4 + , NO 3 - /NH 4 + = 1:1 and NO 2 - /NO 3 - /NH 4 + = 1:1:1) in 90 min were 98.2%, 97.4%, 93.1%, and 98.4%, respectively, and the remaining nitrogen was completely removed by prolonging the reaction time. The rapid reduction of nitrate was ascribed to the capacitor characteristics of Pd-Cu/NF that promoted nitrate adsorption in the presence of an electric double layer, eliminating repulsion between the cathode and the anion. Nitrate was effectively removed with a rate constant of 0.050 min -1 , which was 33 times larger than that of Pt cathode. This system shows great potential for inorganic nitrogen treatment due to the high rate, low cost, and clean energy source.

Methane-Oxidizing Enzymes: An Upstream Problem in Biological Gas-to-Liquids Conversion

PubMed Central

Lawton, Thomas J.; Rosenzweig, Amy C.

2017-01-01

Biological conversion of natural gas to liquids (Bio-GTL) represents an immense economic opportunity. In nature, aerobic methanotrophic bacteria and anaerobic archaea are able to selectively oxidize methane using methane monooxygenase (MMO) and methyl coenzyme M reductase (MCR) enzymes. Although significant progress has been made toward genetically manipulating these organisms for biotechnological applications, the enzymes themselves are slow, complex, and not recombinantly tractable in traditional industrial hosts. With turnover numbers of 0.16–13 s−1, these enzymes pose a considerable upstream problem in the biological production of fuels or chemicals from methane. Methane oxidation enzymes will need to be engineered to be faster to enable high volumetric productivities; however, efforts to do so and to engineer simpler enzymes have been minimally successful. Moreover, known methane-oxidizing enzymes have different expression levels, carbon and energy efficiencies, require auxiliary systems for biosynthesis and function, and vary considerably in terms of complexity and reductant requirements. The pros and cons of using each methane-oxidizing enzyme for Bio-GTL are considered in detail. The future for these enzymes is bright, but a renewed focus on studying them will be critical to the successful development of biological processes that utilize methane as a feedstock. PMID:27366961

An alternative to hydrogenation processes. Electrocatalytic hydrogenation of benzophenone.

PubMed

Mozo Mulero, Cristina; Sáez, Alfonso; Iniesta, Jesús; Montiel, Vicente

2018-01-01

The electrocatalytic hydrogenation of benzophenone was performed at room temperature and atmospheric pressure using a polymer electrolyte membrane electrochemical reactor (PEMER). Palladium (Pd) nanoparticles were synthesised and supported on a carbonaceous matrix (Pd/C) with a 28 wt % of Pd with respect to carbon material. Pd/C was characterised by transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). Cathodes were prepared using Pd electrocatalytic loadings (L Pd ) of 0.2 and 0.02 mg cm -2 . The anode consisted of hydrogen gas diffusion for the electrooxidation of hydrogen gas, and a 117 Nafion exchange membrane acted as a cationic polymer electrolyte membrane. Benzophenone solution was electrochemically hydrogenated in EtOH/water (90/10 v/v) plus 0.1 M H 2 SO 4 . Current densities of 10, 15 and 20 mA cm -2 were analysed for the preparative electrochemical hydrogenation of benzophenone and such results led to the highest fractional conversion (X R ) of around 30% and a selectivity over 90% for the synthesis of diphenylmethanol upon the lowest current density. With regards to an increase by ten times the Pd electrocatalytic loading the electrocatalytic hydrogenation led neither to an increase in fractional conversion nor to a change in selectivity.

An alternative to hydrogenation processes. Electrocatalytic hydrogenation of benzophenone

PubMed Central

Mozo Mulero, Cristina; Iniesta, Jesús; Montiel, Vicente

2018-01-01

The electrocatalytic hydrogenation of benzophenone was performed at room temperature and atmospheric pressure using a polymer electrolyte membrane electrochemical reactor (PEMER). Palladium (Pd) nanoparticles were synthesised and supported on a carbonaceous matrix (Pd/C) with a 28 wt % of Pd with respect to carbon material. Pd/C was characterised by transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). Cathodes were prepared using Pd electrocatalytic loadings (LPd) of 0.2 and 0.02 mg cm−2. The anode consisted of hydrogen gas diffusion for the electrooxidation of hydrogen gas, and a 117 Nafion exchange membrane acted as a cationic polymer electrolyte membrane. Benzophenone solution was electrochemically hydrogenated in EtOH/water (90/10 v/v) plus 0.1 M H2SO4. Current densities of 10, 15 and 20 mA cm−2 were analysed for the preparative electrochemical hydrogenation of benzophenone and such results led to the highest fractional conversion (XR) of around 30% and a selectivity over 90% for the synthesis of diphenylmethanol upon the lowest current density. With regards to an increase by ten times the Pd electrocatalytic loading the electrocatalytic hydrogenation led neither to an increase in fractional conversion nor to a change in selectivity. PMID:29623115

Methane-Oxidizing Enzymes: An Upstream Problem in Biological Gas-to-Liquids Conversion.

PubMed

Lawton, Thomas J; Rosenzweig, Amy C

2016-08-03

Biological conversion of natural gas to liquids (Bio-GTL) represents an immense economic opportunity. In nature, aerobic methanotrophic bacteria and anaerobic archaea are able to selectively oxidize methane using methane monooxygenase (MMO) and methyl coenzyme M reductase (MCR) enzymes. Although significant progress has been made toward genetically manipulating these organisms for biotechnological applications, the enzymes themselves are slow, complex, and not recombinantly tractable in traditional industrial hosts. With turnover numbers of 0.16-13 s(-1), these enzymes pose a considerable upstream problem in the biological production of fuels or chemicals from methane. Methane oxidation enzymes will need to be engineered to be faster to enable high volumetric productivities; however, efforts to do so and to engineer simpler enzymes have been minimally successful. Moreover, known methane-oxidizing enzymes have different expression levels, carbon and energy efficiencies, require auxiliary systems for biosynthesis and function, and vary considerably in terms of complexity and reductant requirements. The pros and cons of using each methane-oxidizing enzyme for Bio-GTL are considered in detail. The future for these enzymes is bright, but a renewed focus on studying them will be critical to the successful development of biological processes that utilize methane as a feedstock.

Initial development and performance evaluation of a process for formation of dense carbon by pyrolysis of methane

NASA Technical Reports Server (NTRS)

Noyes, G. P.; Cusick, R. J.

1985-01-01

The three steps in pyrolytic carbon formation are: (1) gaseous hydrocarbon polymerization and aromatic formation; (2) gas-phase condensation and surface adsorption/impingement of polyaromatic hydrocarbon; and (3) final dehydration to carbon. The structure of the carbon in the various stages of formation is examined. The apparatuses and experimental procedures for the pyrolysis of methane in a 60 cm long quartz reactor tube at temperatures ranging from 1400-1600 K are described. The percentage of carbon converted and its density are calculated and tabularly presented. The results reveal that dense carbon formation is maximized and soot eliminated by this procedure. It is observed that conversion efficiency depends on the composition of the inlet gas and conversion increases with increasing temperature. Based on the experimental data a three-man carbon reactor subsystem (CRS) is developed; the functions of the Sabatier Methanation Reactor, two carbon formation reactors and fluid handling components of the CRS are analyzed. The CRS forms 16 kg of carbon at a rate of 0.8 kg/day for 20 days in a two percent volume density quartz wool packing at temperature of 1500-1600 K.

The keto-enol equilibrium and thermal conversion kinetics of 2- and 4-hydroxyacetophenone in the gas phase: a DFT study

NASA Astrophysics Data System (ADS)

Monascal, Yeljair; Gallardo, Eliana; Cartaya, Loriett; Maldonado, Alexis; Bentarcurt, Yenner; Chuchani, Gabriel

2018-01-01

Keto-enol tautomeric equilibrium and the mechanism of thermal conversion of 2- and 4-hydroxyacetophenone in gas phase have been studied by means of electronic structure calculations using density functional theory (DFT). A topological analysis of electron density evidence that the structure of keto and enol forms of 2-hydroxyacetophenone are stabilised by a relatively strong intramolecular hydrogen bond. 2- and 4-hydroxyacetophenone undergo deacetylation reactions yielding phenol and ketene. Two possible mechanisms are considered for these eliminations: the process takes place from the keto form (mechanism A), or occurs from the enolic form of the substrate (mechanism B). Quantum chemical calculations support the mechanism B, being found a good agreement with the experimental activation parameters. These results suggest that the rate-limiting step is the reaction of the enol through a concerted, non-synchronous, semi-polar, four-membered cyclic transition state (TS). The most advanced reaction coordinate in the TS is the rupture of O1...H1 bond, with an evolution in the order of 79.7%-80.9%. Theoretical results also suggest a three-step mechanism for the phenyl acetate formation from 2-hydroxyacetophenone.

11. Photograph of a line drawing. 'CROSS SECTION OF GAS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. Photograph of a line drawing. 'CROSS SECTION OF GAS PRODUCER.' From George R. Cooper (Wilputte Corporation). 'Operating Overview of a Producer Gas Plant (12 Machines) at Kingsport, Tennessee.' Presented at the Fifth Annual International Conference on Coal Gasification, Liquefaction and Conversion to Electricity. University of Pittsburgh, August 2, 1978. - Holston Army Ammunition Plant, Producer Gas Plant, Kingsport, Sullivan County, TN

The potential to build current natural gas infrastructure to accommodate the future conversion to near-zero transportation technology : a research report from the National Center for Sustainable Transportation.

DOT National Transportation Integrated Search

2017-03-01

The emergence of natural gas as an abundant, inexpensive fuel in the United States has highlighted the possibility that natural gas could play a significant role in the transition to low carbon fuels. Natural gas is often cited as a bridge to l...

Multifunctional two-stage riser fluid catalytic cracking process.

PubMed

Zhang, Jinhong; Shan, Honghong; Chen, Xiaobo; Li, Chunyi; Yang, Chaohe

This paper described the discovering process of some shortcomings of the conventional fluid catalytic cracking (FCC) process and the proposed two-stage riser (TSR) FCC process for decreasing dry gas and coke yields and increasing light oil yield, which has been successfully applied in 12 industrial units. Furthermore, the multifunctional two-stage riser (MFT) FCC process proposed on the basis of the TSR FCC process was described, which were carried out by the optimization of reaction conditions for fresh feedstock and cycle oil catalytic cracking, respectively, by the coupling of cycle oil cracking and light FCC naphtha upgrading processes in the second-stage riser, and the specially designed reactor for further reducing the olefin content of gasoline. The pilot test showed that it can further improve the product quality, increase the diesel yield, and enhance the conversion of heavy oil.

Simplified conditions holding at the gas-liquid interface during evaporation

NASA Astrophysics Data System (ADS)

Morris, S. J. S.

2017-11-01

We show that on the gas side of the interface between a pure liquid and a binary mixture of its vapour with an insoluble gas, the normal derivative of vapour partial pressure pv satisfies ∂pv/∂n +αc/2 πpD (P -pv) (p -pv) = 0 . Constants α, c, D denote the dimensionless accommodation coefficient, a molecular speed and the diffusivity. Provided the continuum approximation holds within the gas, and α = O(1) , this boundary condition implies that evaporation can take one of two forms. (a) If the coexistence pressure P evaluated at the interface is less than the constant total gas pressure p, liquid at the interface is in local thermodynamic equilibrium with its vapour, and the evaporation rate is determined by diffusion through the gas. (b) Conversely, if P > p , gas at the interface consists of pure vapour, and the evaporation rate is determined by processes within the liquid. In the Wayner theory of the heated evaporating meniscus, such as that in a heat pipe, case (b) is assumed. As an application of our result, we show that some of the published experiments intended to test the Wayner theory instead operate under conditions in which case (a) holds. As a result, they do not perform the test intended.

Fuel development for gas-cooled fast reactors

NASA Astrophysics Data System (ADS)

Meyer, M. K.; Fielding, R.; Gan, J.

2007-09-01

The Generation IV Gas-cooled Fast Reactor (GFR) concept is proposed to combine the advantages of high-temperature gas-cooled reactors (such as efficient direct conversion with a gas turbine and the potential for application of high-temperature process heat), with the sustainability advantages that are possible with a fast-spectrum reactor. The latter include the ability to fission all transuranics and the potential for breeding. The GFR is part of a consistent set of gas-cooled reactors that includes a medium-term Pebble Bed Modular Reactor (PBMR)-like concept, or concepts based on the Gas Turbine Modular Helium Reactor (GT-MHR), and specialized concepts such as the Very High-Temperature Reactor (VHTR), as well as actinide burning concepts [A Technology Roadmap for Generation IV Nuclear Energy Systems, US DOE Nuclear Energy Research Advisory Committee and the Generation IV International Forum, December 2002]. To achieve the necessary high power density and the ability to retain fission gas at high temperature, the primary fuel concept proposed for testing in the United States is dispersion coated fuel particles in a ceramic matrix. Alternative fuel concepts considered in the US and internationally include coated particle beds, ceramic clad fuel pins, and novel ceramic 'honeycomb' structures. Both mixed carbide and mixed nitride-based solid solutions are considered as fuel phases.

Steam gasification of a thermally pretreated high lignin corn stover simultaneous saccharification and fermentation digester residue

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

Howe, Daniel T.; Taasevigen, Danny; Garcia-Perez, Manuel

Efficient conversion of all components in lignocellulosic biomass is essential to realizing economic feasibility of biorefineries. However, when utilizing biochemical pathways, lignin cannot be fermented. Furthermore, the high lignin and high ash residue resulting from simultaneous saccharification and fermentation (SSF) reactors is difficult to thermochemically process due to feed line plugging and bed agglomeration. In this study a corn stover SSF digester residue was thermally pretreated at 300°C for 22.5 minutes (min) and then gasified in a bubbling fluidized bed gasifier to study the effect of thermal pretreatment on its processing behavior. Untreated, pelletized SSF residue was gasified at themore » same conditions to establish the baseline processing behavior. Results indicate that the thermal pretreatment process removes a substantial portion of the polar and non-polar extractives, with a resultant increase in the concentration of lignin, cellulose, and ash. Feed line plugging was not observed, although bed agglomeration was occurring at similar rates for both feedstocks, suggesting that overall ash content is the most important factor affecting bed agglomeration. Benzene, phenol, and polyaromatic hydrocarbons in the tar were present at higher concentrations in the treated material, with higher tar loading in the product gas. Total product gas generation is lower for the treated material, although the overall gas composition does not change.« less

Hydraulic fracturing for natural gas: impact on health and environment.

PubMed

Carpenter, David O

2016-03-01

Shale deposits exist in many parts of the world and contain relatively large amounts of natural gas and oil. Recent technological developments in the process of horizontal hydraulic fracturing (hydrofracturing or fracking) have suddenly made it economically feasible to extract natural gas from shale. While natural gas is a much cleaner burning fuel than coal, there are a number of significant threats to human health from the extraction process as currently practiced. There are immediate threats to health resulting from air pollution from volatile organic compounds, which contain carcinogens such as benzene and ethyl-benzene, and which have adverse neurologic and respiratory effects. Hydrogen sulfide, a component of natural gas, is a potent neuro- and respiratory toxin. In addition, levels of formaldehyde are elevated around fracking sites due to truck traffic and conversion of methane to formaldehyde by sunlight. There are major concerns about water contamination because the chemicals used can get into both ground and surface water. Much of the produced water (up to 40% of what is injected) comes back out of the gas well with significant radioactivity because radium in subsurface rock is relatively water soluble. There are significant long-term threats beyond cancer, including exacerbation of climate change due to the release of methane into the atmosphere, and increased earthquake activity due to disruption of subsurface tectonic plates. While fracking for natural gas has significant economic benefits, and while natural gas is theoretically a better fossil fuel as compared to coal and oil, current fracking practices pose significant adverse health effects to workers and near-by residents. The health of the public should not be compromized simply for the economic benefits to the industry.

Effect of Process Parameters on Catalytic Incineration of Solvent Emissions

PubMed Central

Ojala, Satu; Lassi, Ulla; Perämäki, Paavo; Keiski, Riitta L.

2008-01-01

Catalytic oxidation is a feasible and affordable technology for solvent emission abatement. However, finding optimal operation conditions is important, since they are strongly dependent on the application area of VOC incineration. This paper presents the results of the laboratory experiments concerning four most central parameters, that is, effects of concentration, gas hourly space velocity (GHSV), temperature, and moisture on the oxidation of n-butyl acetate. Both fresh and industrially aged commercial Pt/Al2O3 catalysts were tested to determine optimal process conditions and the significance order and level of selected parameters. The effects of these parameters were evaluated by computer-aided statistical experimental design. According to the results, GHSV was the most dominant parameter in the oxidation of n-butyl acetate. Decreasing GHSV and increasing temperature increased the conversion of n-butyl acetate. The interaction effect of GHSV and temperature was more significant than the effect of concentration. Both of these affected the reaction by increasing the conversion of n-butyl acetate. Moisture had only a minor decreasing effect on the conversion, but it also decreased slightly the formation of by products. Ageing did not change the significance order of the above-mentioned parameters, however, the effects of individual parameters increased slightly as a function of ageing. PMID:18584032

Controlling initial biodegradation of magnesium by a biocompatible strontium phosphate conversion coating.

PubMed

Chen, X B; Nisbet, D R; Li, R W; Smith, P N; Abbott, T B; Easton, M A; Zhang, D-H; Birbilis, N

2014-03-01

A simple strontium phosphate (SrP) conversion coating process was developed to protect magnesium (Mg) from the initial degradation post-implantation. The coating morphology, deposition rate and resultant phases are all dependent on the processing temperature, which determines the protective ability for Mg in minimum essential medium (MEM). Coatings produced at 80 °C are primarily made up of strontium apatite (SrAp) with a granular surface, a high degree of crystallinity and the highest protective ability, which arises from retarding anodic dissolution of Mg in MEM. Following 14 days' immersion in MEM, the SrAp coating maintained its integrity with only a small fraction of the surface corroded. The post-degradation effect of uncoated Mg and Mg coated at 40 and 80 °C on the proliferation and differentiation of human mesenchymal stem cells was also studied, revealing that the SrP coatings are biocompatible and permit proliferation to a level similar to that of pure Mg. The present study suggests that the SrP conversion coating is a promising option for controlling the early rapid degradation rate, and hence hydrogen gas evolution, of Mg implants without adverse effects on surrounding cells and tissues. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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

Snowden-Swan, Lesley J.; Spies, Kurt A.; Lee, Guo-Shuh J.

Bio-oil from fast pyrolysis of biomass requires multi-stage catalytic hydroprocessing to produce hydrocarbon drop-in fuels. The current proposed process design involves fixed beds of ruthenium-based catalyst and conventional petroleum hydrotreating catalyst. Similar to petroleum processing, the catalyst is spent as a result of coking and other deactivation mechanisms, and must be changed out periodically. Biofuel life cycle greenhouse gas (GHG) assessments typically ignore the impact of catalyst consumed during fuel conversion as a result of limited lifetime, representing a data gap in the analyses. To help fill this data gap, life cycle GHGs were estimated for two representative examples ofmore » fast pyrolysis bio-oil hydrotreating catalyst, NiMo/Al2O3 and Ru/C, and integrated into the conversion-stage GHG analysis. Life cycle GHGs for the NiMo/Al2O3 and Ru/C catalysts are estimated at 5.5 and 81 kg CO2-e/kg catalyst, respectively. Contribution of catalyst consumption to total conversion-stage GHGs is 0.5% for NiMo/Al2O3 and 5% for Ru/C. This analysis does not consider secondary sourcing of metals for catalyst manufacture and therefore these are likely to be conservative estimates compared to applications where a spent catalyst recycler can be used.« less

Mission analysis for the federal fuels from biomass program. Volume IV. Termochemical conversion of biomass to fuels and chemicals

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

Kohan, S.M.; Barkhordar, P.M.

1979-01-01

The thermochemical conversion of biomass feedstocks generally denotes technologies that use elevated temperatures to convert the fixed carbon content of biomass materials to produce other, more useful energy forms. Examples are combustion to produce heat, steam, electricity, or combinations of these; pyrolysis to produce gas (low- or intermediate-Btu), pyrolytic liquids and chemicals, and char; gasification to produce low or intermediate Btu gas (and, from IBG, additional products such as SNG, ammonia, methanol, or Fischer-Tropsch liquids); and liquefaction to produce heavy fuel oil or, with upgrading, lighter-boiling liquid products such as distillates, light fuel oils, or gasoline. This section discusses themore » selection of the feedstock used in the analysis of thermochemical conversion technologies. The following sections present detailed technical and economic evaluations of biomass conversion to electricity and steam by combustion, SNG by gasification and methanation, methanol by gasification and synthesis, oil by catalytic liquefaction, oil and char by pyrolysis, and ammonia by gasification and synthesis. The conversion options were reviewed with DOE for approval at the start of the project.« less

Preliminary conceptual design for geothermal space heating conversion of school district 50 joint facilities at Pagosa Springs, Colorado. GTA report no. 6

NASA Astrophysics Data System (ADS)

Engen, I. A.

1981-11-01

This feasibility study and preliminary conceptual design effect assesses the conversion of a high school and gym, and a middle school building to geothermal space heating is assessed. A preliminary cost benefit assessment made on the basis of estimated costs for conversion, system maintenance, debt service, resource development, electricity to power pumps, and savings from from reduced natural gas consumption concluded that an economic conversion depended on development of an adequate geothermal resource (approximately 1500F, 400 gpm). Material selection assumed that the geothermal water to the main supply system was isolated to minimize effects of corrosion and deposition, and that system compatible components are used for the building modifications. Asbestos cement distribution pipe, a stainless steel heat exchanger, and stainless steel lined valves were recommended for the supply, heat transfer, and disposal mechanisms, respectively. A comparison of the calculated average gas consumption cost, escalated at 10% per year, with conversion project cost, both in 1977 dollars, showed that the project could be amortized over less than 20 years at current interest rates.

Megawatt Class Nuclear Space Power Systems (MCNSPS) conceptual design and evaluation report. Volume 1: Objectives, summary results and introduction

NASA Technical Reports Server (NTRS)

Wetch, J. R.

1988-01-01

The objective was to determine which reactor, conversion, and radiator technologies would best fulfill future Megawatt Class Nuclear Space Power System Requirements. Specifically, the requirement was 10 megawatts for 5 years of full power operation and 10 years systems life on orbit. A variety of liquid metal and gas cooled reactors, static and dynamic conversion systems, and passive and dynamic radiators were considered. Four concepts were selected for more detailed study. The concepts are: a gas cooled reactor with closed cycle Brayton turbine-alternator conversion with heat pipe and pumped tube-fin heat rejection; a lithium cooled reactor with a free piston Stirling engine-linear alternator and a pumped tube-fin radiator; a lithium cooled reactor with potassium Rankine turbine-alternator and heat pipe radiator; and a lithium cooled incore thermionic static conversion reactor with a heat pipe radiator. The systems recommended for further development to meet a 10 megawatt long life requirement are the lithium cooled reactor with the K-Rankine conversion and heat pipe radiator, and the lithium cooled incore thermionic reactor with heat pipe radiator.

Numerical and experimental studies on effects of moisture content on combustion characteristics of simulated municipal solid wastes in a fixed bed

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

Sun, Rui, E-mail: Sunsr@hit.edu.cn; Ismail, Tamer M., E-mail: temoil@aucegypt.edu; Ren, Xiaohan

Highlights: • The effects of moisture content on the burning process of MSW are investigated. • A two-dimensional mathematical model was built to simulate the combustion process. • Temperature distributions, process rates, gas species were measured and simulated. • The The conversion ratio of C/CO and N/NO in MSW are inverse to moisture content. - Abstract: In order to reveal the features of the combustion process in the porous bed of a waste incinerator, a two-dimensional unsteady state model and experimental study were employed to investigate the combustion process in a fixed bed of municipal solid waste (MSW) on themore » combustion process in a fixed bed reactor. Conservation equations of the waste bed were implemented to describe the incineration process. The gas phase turbulence was modeled using the k–ε turbulent model and the particle phase was modeled using the kinetic theory of granular flow. The rate of moisture evaporation, devolatilization rate, and char burnout was calculated according to the waste property characters. The simulation results were then compared with experimental data for different moisture content of MSW, which shows that the incineration process of waste in the fixed bed is reasonably simulated. The simulation results of solid temperature, gas species and process rate in the bed are accordant with experimental data. Due to the high moisture content of fuel, moisture evaporation consumes a vast amount of heat, and the evaporation takes up most of the combustion time (about 2/3 of the whole combustion process). The whole bed combustion process reduces greatly as MSW moisture content increases. The experimental and simulation results provide direction for design and optimization of the fixed bed of MSW.« less

Comparative techno-economic analysis and process design for indirect liquefaction pathways to distillate-range fuels via biomass-derived oxygenated intermediates upgrading: Liquid Transportation Fuel Production via Biomass-derived Oxygenated Intermediates Upgrading

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

Tan, Eric C. D.; Snowden-Swan, Lesley J.; Talmadge, Michael

This paper presents a comparative techno-economic analysis (TEA) of five conversion pathways from biomass to gasoline-, jet-, and diesel-range hydrocarbons via indirect liquefaction with specific focus on pathways utilizing oxygenated intermediates. The four emerging pathways of interest are compared with one conventional pathway (Fischer-Tropsch) for the production of the hydrocarbon blendstocks. The processing steps of the four emerging pathways include: biomass to syngas via indirect gasification, gas cleanup, conversion of syngas to alcohols/oxygenates followed by conversion of alcohols/oxygenates to hydrocarbon blendstocks via dehydration, oligomerization, and hydrogenation. Conversion of biomass-derived syngas to oxygenated intermediates occurs via three different pathways, producing: 1)more » mixed alcohols over a MoS2 catalyst, 2) mixed oxygenates (a mixture of C2+ oxygenated compounds, predominantly ethanol, acetic acid, acetaldehyde, ethyl acetate) using an Rh-based catalyst, and 3) ethanol from syngas fermentation. This is followed by the conversion of oxygenates/alcohols to fuel-range olefins in two approaches: 1) mixed alcohols/ethanol to 1-butanol rich mixture via Guerbet reaction, followed by alcohol dehydration, oligomerization, and hydrogenation, and 2) mixed oxygenates/ethanol to isobutene rich mixture and followed by oligomerization and hydrogenation. The design features a processing capacity of 2,000 tonnes/day (2,205 short tons) of dry biomass. The minimum fuel selling prices (MFSPs) for the four developing pathways range from $3.40 to $5.04 per gasoline-gallon equivalent (GGE), in 2011 US dollars. Sensitivity studies show that MFSPs can be improved with co-product credits and are comparable to the commercial Fischer-Tropsch benchmark ($3.58/GGE). Overall, this comparative TEA study documents potential economics for the developmental biofuel pathways via mixed oxygenates.« less

Megawatt Class Nuclear Space Power Systems (MCNSPS) conceptual design and evaluation report. Volume 3, technologies 2: Power conversion

NASA Technical Reports Server (NTRS)

Wetch, J. R.

1988-01-01

The major power conversion concepts considered for the Megawatt Class Nuclear Space Power System (MCNSPS) are discussed. These concepts include: (1) Rankine alkali-metal-vapor turbine alternators; (2) in-core thermionic conversion; (3) Brayton gas turbine alternators; and (4) free piston Stirling engine linear alternators. Considerations important to the coupling of these four conversion alternatives to an appropriate nuclear reactor heat source are examined along with the comparative performance characteristics of the combined systems meeting MCNSPS requirements.

Zachary-Fort Lauderdale pipeline construction and conversion project: final supplement to final environmental impact statement. Docket No. CP74-192

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

None

This Final Supplement to the Final Environmental Impact Statement (Final Supplement) evaluates the economic, engineering, and environmental aspects of newly developed alternatives to an abandonment/conversion project proposed by Florida Gas Transmission Company (Florida Gas). It also updates the staff's previous FEIS and studies revisions to the original proposal. Wherever possible, the staff has adopted portions of its previous FEIS in lieu of reprinting portions of that analysis which require no change. 60 references, 8 figures, 35 tables.

Surveys of research in the Chemistry Division, Argonne National Laboratory

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

Grazis, B.M.

1992-01-01

Research reports are presented on reactive intermediates in condensed phase (radiation chemistry, photochemistry), electron transfer and energy conversion, photosynthesis and solar energy conversion, metal cluster chemistry, chemical dynamics in gas phase, photoionization-photoelectrons, characterization and reactivity of coal and coal macerals, premium coal sample program, chemical separations, heavy elements coordination chemistry, heavy elements photophysics/photochemistry, f-electron interactions, radiation chemistry of high-level wastes (gas generation in waste tanks), ultrafast molecular electronic devices, and nuclear medicine. Separate abstracts have been prepared. Accelerator activites and computer system/network services are also reported.

Surveys of research in the Chemistry Division, Argonne National Laboratory

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

Grazis, B.M.

1992-11-01

Research reports are presented on reactive intermediates in condensed phase (radiation chemistry, photochemistry), electron transfer and energy conversion, photosynthesis and solar energy conversion, metal cluster chemistry, chemical dynamics in gas phase, photoionization-photoelectrons, characterization and reactivity of coal and coal macerals, premium coal sample program, chemical separations, heavy elements coordination chemistry, heavy elements photophysics/photochemistry, f-electron interactions, radiation chemistry of high-level wastes (gas generation in waste tanks), ultrafast molecular electronic devices, and nuclear medicine. Separate abstracts have been prepared. Accelerator activites and computer system/network services are also reported.

Benefits of advanced technology in industrial cogeneration

NASA Technical Reports Server (NTRS)

Barna, G. J.; Burns, R. K.

1979-01-01

This broad study is aimed at identifying the most attractive advanced energy conversion systems for industrial cogeneration for the 1985 to 2000 time period and assessing the advantages of advanced technology systems compared to using today's commercially available technology. Energy conversion systems being studied include those using steam turbines, open cycle gas turbines, combined cycles, diesel engines, Stirling engines, closed cycle gas turbines, phosphoric acid and molten carbonate fuel cells and thermionics. Specific cases using today's commercially available technology are being included to serve as a baseline for assessing the advantages of advanced technology.

A Commercialization Roadmap for Carbon-Negative Energy Systems

NASA Astrophysics Data System (ADS)

Sanchez, D.

2016-12-01

The Intergovernmental Panel on Climate Change (IPCC) envisages the need for large-scale deployment of net-negative CO2 emissions technologies by mid-century to meet stringent climate mitigation goals and yield a net drawdown of atmospheric carbon. Yet there are few commercial deployments of BECCS outside of niche markets, creating uncertainty about commercialization pathways and sustainability impacts at scale. This uncertainty is exacerbated by the absence of a strong policy framework, such as high carbon prices and research coordination. Here, we propose a strategy for the potential commercial deployment of BECCS. This roadmap proceeds via three steps: 1) via capture and utilization of biogenic CO2 from existing bioenergy facilities, notably ethanol fermentation, 2) via thermochemical co-conversion of biomass and fossil fuels, particularly coal, and 3) via dedicated, large-scale BECCS. Although biochemical conversion is a proven first market for BECCS, this trajectory alone is unlikely to drive commercialization of BECCS at the gigatonne scale. In contrast to biochemical conversion, thermochemical conversion of coal and biomass enables large-scale production of fuels and electricity with a wide range of carbon intensities, process efficiencies and process scales. Aside from systems integration, primarily technical barriers are involved in large-scale biomass logistics, gasification and gas cleaning. Key uncertainties around large-scale BECCS deployment are not limited to commercialization pathways; rather, they include physical constraints on biomass cultivation or CO2 storage, as well as social barriers, including public acceptance of new technologies and conceptions of renewable and fossil energy, which co-conversion systems confound. Despite sustainability risks, this commercialization strategy presents a pathway where energy suppliers, manufacturers and governments could transition from laggards to leaders in climate change mitigation efforts.

The Changing Landscape of Hydrocarbon Feedstocks for Chemical Production: Implications for Catalysis: Proceedings of a Workshop

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

Bell, Alexis T.; Alger, Monty M.; Flytzani-Stephanopoulos, Maria

A decade ago, the U.S. chemical industry was in decline. Of the more than 40 chemical manufacturing plants being built worldwide in the mid-2000s with more than $1 billion in capitalization, none were under construction in the United States. Today, as a result of abundant domestic supplies of affordable natural gas and natural gas liquids resulting from the dramatic rise in shale gas production, the U.S. chemical industry has gone from the world’s highest-cost producer in 2005 to among the lowest-cost producers today. The low cost and increased supply of natural gas and natural gas liquids provides an opportunity tomore » discover and develop new catalysts and processes to enable the direct conversion of natural gas and natural gas liquids into value-added chemicals with a lower carbon footprint. The economic implications of developing advanced technologies to utilize and process natural gas and natural gas liquids for chemical production could be significant, as commodity, intermediate, and fine chemicals represent a higher-economic-value use of shale gas compared with its use as a fuel. To better understand the opportunities for catalysis research in an era of shifting feedstocks for chemical production and to identify the gaps in the current research portfolio, the National Academies of Sciences, Engineering, and Medicine conducted an interactive, multidisciplinary workshop in March 2016. The goal of this workshop was to identify advances in catalysis that can enable the United States to fully realize the potential of the shale gas revolution for the U.S. chemical industry and, as a result, to help target the efforts of U.S. researchers and funding agencies on those areas of science and technology development that are most critical to achieving these advances. This publication summarizes the presentations and discussions from the workshop.« less

40 CFR 98.33 - Calculating GHG emissions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... except when natural gas billing records are used to quantify fuel usage and gas consumption is expressed... consumption is obtained from billing records and fuelusage is expressed in therms, use Equation C-1a. ER17DE10... × 10−3 = Conversion factor from kilograms to metric tons. (iii) If natural gas consumption is obtained...

40 CFR 60.266 - Test methods and procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... effluent gas from exhaust stream “i”, dscm/hr (dscf/hr). P=average furnace power input, MW. K=conversion....8, the owner or operator shall not allow gaseous diluents to be added to the effluent gas stream after the fabric in an open pressurized fabric filter collector unless the total gas volume flow from...

40 CFR 60.73 - Emission monitoring.

Code of Federal Regulations, 2011 CFR

2011-07-01

... the applicable standard (kg/metric ton, lb/ton). The conversion factor shall be established by...., kg/metric ton per ppm (lb/ton per ppm). The conversion factor shall be reestablished during any... continuous monitoring system for measuring nitrogen oxides (NOX). The pollutant gas mixtures under...

40 CFR 60.73 - Emission monitoring.

Code of Federal Regulations, 2013 CFR

2013-07-01

... the applicable standard (kg/metric ton, lb/ton). The conversion factor shall be established by...., kg/metric ton per ppm (lb/ton per ppm). The conversion factor shall be reestablished during any... continuous monitoring system for measuring nitrogen oxides (NOX). The pollutant gas mixtures under...

40 CFR 60.73 - Emission monitoring.

Code of Federal Regulations, 2012 CFR

2012-07-01

... the applicable standard (kg/metric ton, lb/ton). The conversion factor shall be established by...., kg/metric ton per ppm (lb/ton per ppm). The conversion factor shall be reestablished during any... continuous monitoring system for measuring nitrogen oxides (NOX). The pollutant gas mixtures under...

40 CFR 60.73 - Emission monitoring.

Code of Federal Regulations, 2014 CFR

2014-07-01

... the applicable standard (kg/metric ton, lb/ton). The conversion factor shall be established by...., kg/metric ton per ppm (lb/ton per ppm). The conversion factor shall be reestablished during any... continuous monitoring system for measuring nitrogen oxides (NOX). The pollutant gas mixtures under...

Resonant third harmonic generation of KrF laser in Ar gas.

PubMed

Rakowski, R; Barna, A; Suta, T; Bohus, J; Földes, I B; Szatmári, S; Mikołajczyk, J; Bartnik, A; Fiedorowicz, H; Verona, C; Verona Rinati, G; Margarone, D; Nowak, T; Rosiński, M; Ryć, L

2014-12-01

Investigations of emission of harmonics from argon gas jet irradiated by 700 fs, 5 mJ pulses from a KrF laser are presented. Harmonics conversion was optimized by varying the experimental geometry and the nozzle size. For the collection of the harmonic radiation silicon and solar-blind diamond semiconductor detectors equipped with charge preamplifiers were applied. The possibility of using a single-crystal CVD diamond detector for separate measurement of the 3rd harmonic in the presence of a strong pumping radiation was explored. Our experiments show that the earlier suggested 0.7% conversion efficiency can really be obtained, but only in the case when phase matching is optimized with an elongated gas target length corresponding to the length of coherence.

Conversion of deuterium gas to heavy water by catalytic isotopic exchange using wetproof catalyst

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

Quaiattini, R.J.; McGauley, M.P.; Burns, D.L.

The invention at Chalk River Nuclear Laboratories of a simple method of wetproofing platinum catalysts allows them to retain their activity in liquid water. High performance catalysts for the hydrogen-water isotope exchange reaction that remain active for years can now be routinely produced. The first commercial application using the ordered-bed-type wetproofed isotope exchange catalyst developed and patented by Atomic Energy of Canada Ltd. has been successfully completed. Approximately 9100 m/sup 3/ of deuterium gas stored at Brookhaven National Laboratory was converted to high grade heavy water. Conversion efficiency exceeded 99.8%. The product D/sub 2/O concentration was 6.7 percentage points highermore » than the feed D/sub 2/ gas.« less

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.

Direct analysis of ultra-trace semiconductor gas by inductively coupled plasma mass spectrometry coupled with gas to particle conversion-gas exchange technique.

PubMed

Ohata, Masaki; Sakurai, Hiromu; Nishiguchi, Kohei; Utani, Keisuke; Günther, Detlef

2015-09-03

An inductively coupled plasma mass spectrometry (ICPMS) coupled with gas to particle conversion-gas exchange technique was applied to the direct analysis of ultra-trace semiconductor gas in ambient air. The ultra-trace semiconductor gases such as arsine (AsH3) and phosphine (PH3) were converted to particles by reaction with ozone (O3) and ammonia (NH3) gases within a gas to particle conversion device (GPD). The converted particles were directly introduced and measured by ICPMS through a gas exchange device (GED), which could penetrate the particles as well as exchange to Ar from either non-reacted gases such as an air or remaining gases of O3 and NH3. The particle size distribution of converted particles was measured by scanning mobility particle sizer (SMPS) and the results supported the elucidation of particle agglomeration between the particle converted from semiconductor gas and the particle of ammonium nitrate (NH4NO3) which was produced as major particle in GPD. Stable time-resolved signals from AsH3 and PH3 in air were obtained by GPD-GED-ICPMS with continuous gas introduction; however, the slightly larger fluctuation, which could be due to the ionization fluctuation of particles in ICP, was observed compared to that of metal carbonyl gas in Ar introduced directly into ICPMS. The linear regression lines were obtained and the limits of detection (LODs) of 1.5 pL L(-1) and 2.4 nL L(-1) for AsH3 and PH3, respectively, were estimated. Since these LODs revealed sufficiently lower values than the measurement concentrations required from semiconductor industry such as 0.5 nL L(-1) and 30 nL L(-1) for AsH3 and PH3, respectively, the GPD-GED-ICPMS could be useful for direct and high sensitive analysis of ultra-trace semiconductor gas in air. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

NREL Advancements in Methane Conversion Lead to Cleaner Air, Useful Products

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

2016-06-01

Researchers at NREL leveraged the recent on-site development of gas fermentation capabilities and novel genetic tools to directly convert methane to lactic acid using an engineered methanotrophic bacterium. The results provide proof-of-concept data for a gas-to-liquids bioprocess that concurrently produces fuels and chemicals from methane. NREL researchers developed genetic tools to express heterologous genes in methanotrophic organisms, which have historically been difficult to genetically engineer. Using these tools, researchers demonstrated microbial conversion of methane to lactate, a high-volume biochemical precursor predominantly utilized for the production of bioplastics. Methane biocatalysis offers a means to concurrently liquefy and upgrade natural gas andmore » renewable biogas, enabling their utilization in conventional transportation and industrial manufacturing infrastructure. Producing chemicals and fuels from methane expands the suite of products currently generated from biorefineries, municipalities, and agricultural operations, with the potential to increase revenue and significantly reduce greenhouse gas emissions.« less

Commercial-scale demonstration of the Liquid Phase Methanol (LPMEOH{trademark}) process. Technical progress report number 9, July 1--September 30, 1996

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

NONE

The Liquid Phase Methanol (LPMEOH{trademark}) Demonstration Project at Kingsport, Tennessee, is a $213.7 million cooperative agreement between the US Department of Energy (DOE) and Air Products Liquid Phase Conversion Company, L.P. (the Partnership). The LPMEOH{trademark} Process Demonstration Unit is being built at a site located at the Eastman Chemical Company (Eastman) complex in Kingsport. The project involves the construction of an 80,000 gallons per day (260 tons per day (TPD)) methanol unit utilizing coal-derived synthesis gas from Eastman`s integrated coal gasification facility. The new equipment consists of synthesis gas feed preparation and compression facilities, the liquid phase reactor and auxiliaries,more » product distillation facilities, and utilities. This liquid phase process suspends fine catalyst particles in an inert liquid, forming a slurry. The slurry dissipates the heat of the chemical reaction away from the catalyst surface, protecting the catalyst and allowing the methanol synthesis reaction to proceed at higher rates. At the Eastman complex, the technology is being integrated with existing coal-gasifiers.« less

Highly efficient SO₂ absorption and its subsequent utilization by weak base/polyethylene glycol binary system.

PubMed

Yang, Zhen-Zhen; He, Liang-Nian; Zhao, Ya-Nan; Yu, Bing

2013-02-05

A binary system consisting of polyethylene glycol (PEG, proton donor)/PEG-functionalized base with suitable basicity was developed for efficient gas desulfurization (GDS) and can be regarded as an alternative approach to circumvent the energy penalty problem in the GDS process. High capacity for SO(2) capture up to 4.88 mol of SO(2)/mol of base was achieved even under low partial pressure of SO(2). Furthermore, SO(2) desorption runs smoothly under mild conditions (N(2), 25 °C) and no significant drop in SO(2) absorption was observed after five-successive absorption-desorption cycles. On the other hand, the absorbed SO(2) by PEG(150)MeIm/PEG(150), being considered as the activated form of SO(2), can be directly transformed into value-added chemicals under mild conditions, thus eliminating the energy penalty for SO(2) desorption and simultaneously realizing recycle of the absorbents. Thus, this SO(2) capture and utilization (SCU) process offers an alternative way for GDS and potentially enables the SO(2) conversion from flue gas to useful chemicals as a value-added process.

Computational model of collisional-radiative nonequilibrium plasma in an air-driven type laser propulsion

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

Ogino, Yousuke; Ohnishi, Naofumi

A thrust power of a gas-driven laser-propulsion system is obtained through interaction with a propellant gas heated by a laser energy. Therefore, understanding the nonequilibrium nature of laser-produced plasma is essential for increasing available thrust force and for improving energy conversion efficiency from a laser to a propellant gas. In this work, a time-dependent collisional-radiative model for air plasma has been developed to study the effects of nonequilibrium atomic and molecular processes on population densities for an air-driven type laser propulsion. Many elementary processes are considered in the number density range of 10{sup 12}/cm{sup 3}<=N<=10{sup 19}/cm{sup 3} and the temperaturemore » range of 300 K<=T<=40,000 K. We then compute the unsteady nature of pulsively heated air plasma. When the ionization relaxation time is the same order as the time scale of a heating pulse, the effects of unsteady ionization are important for estimating air plasma states. From parametric computations, we determine the appropriate conditions for the collisional-radiative steady state, local thermodynamic equilibrium, and corona equilibrium models in that density and temperature range.« less

Preparation of ortho-para ratio controlled D2 gas for muon-catalyzed fusion.

PubMed

Imao, H; Ishida, K; Kawamura, N; Matsuzaki, T; Matsuda, Y; Toyoda, A; Strasser, P; Iwasaki, M; Nagamine, K

2008-05-01

A negative muon in hydrogen targets, e.g., D2 or D-T mixture, can catalyze nuclear fusions following a series of atomic processes involving muonic hydrogen molecular formation (muon-catalyzed fusion, muCF). The ortho-para state of D2 is a crucial parameter not only for enhancing the fusion rate but also to precisely investigate various muonic atom processes. We have developed a system for controlling and measuring the ortho-para ratio of D2 gas for muCF experiments. We successfully collected para-enriched D2 without using liquid-hydrogen coolant. Ortho-enriched D2 was also obtained by using a catalytic conversion method with a mixture of chromium oxide and alumina. The ortho-para ratio of D2 gas was measured with a compact Raman spectroscopy system. We produced large volume (5-30 l at STP), high-purity (less than ppm high-Z contaminant) D2 targets with a wide range of ortho-para ratios (ortho 20%-99%). By using the ortho-para controlled D2 in muCF experiments, we observed the dependence of muCF phenomena on the ortho-para ratio.

Preparation of ortho-para ratio controlled D{sub 2} gas for muon-catalyzed fusion

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

Imao, H.; Ishida, K.; Matsuzaki, T.

2008-05-15

A negative muon in hydrogen targets, e.g., D{sub 2} or D-T mixture, can catalyze nuclear fusions following a series of atomic processes involving muonic hydrogen molecular formation (muon-catalyzed fusion, {mu}CF). The ortho-para state of D{sub 2} is a crucial parameter not only for enhancing the fusion rate but also to precisely investigate various muonic atom processes. We have developed a system for controlling and measuring the ortho-para ratio of D{sub 2} gas for {mu}CF experiments. We successfully collected para-enriched D{sub 2} without using liquid-hydrogen coolant. Ortho-enriched D{sub 2} was also obtained by using a catalytic conversion method with a mixturemore » of chromium oxide and alumina. The ortho-para ratio of D{sub 2} gas was measured with a compact Raman spectroscopy system. We produced large volume (5-30 l at STP), high-purity (less than ppm high-Z contaminant) D{sub 2} targets with a wide range of ortho-para ratios (ortho 20%-99%). By using the ortho-para controlled D{sub 2} in {mu}CF experiments, we observed the dependence of {mu}CF phenomena on the ortho-para ratio.« less

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.

Pyrolysis of wastewater sludge and composted organic fines from municipal solid waste: laboratory reactor characterisation and product distribution.

PubMed

Agar, David A; Kwapinska, Marzena; Leahy, James J

2018-02-26

Sludge from municipal wastewater treatment plants and organic fines from mechanical sorting of municipal solid waste (MSW) are two common widespread waste streams that are becoming increasingly difficult to utilise. Changing perceptions of risk in food production has limited the appeal of sludge use on agricultural land, and outlets via landfilling are diminishing rapidly. These factors have led to interest in thermal conversion technologies whose aim is to recover energy and nutrients from waste while reducing health and environmental risks associated with material re-use. Pyrolysis yields three output products: solid char, liquid oils and gas. Their relative distribution depends on process parameters which can be somewhat optimised depending on the end use of product. The potential of pyrolysis for the conversion of wastewater sludge (SS) and organic fines of MSW (OF) to a combustion gas and a carbon-rich char has been investigated. Pyrolysis of SS and OF was done using a laboratory fixed-bed reactor. Herein, the physical characterisation of the reactor is described, and results on pyrolysis yields are presented. Feedstock and chars have been characterised using standard laboratory methods, and the composition of pyrolysis gases was analysed using micro gas chromatography. Product distribution (char/liquid/gas) from the pyrolysis of sewage sludge and composted MSW fines at 700°C for 10 min were 45/26/29 and 53/14/33%, respectively. The combustible fractions of pyrolysis gases range from 36 to 54% for SS feedstock and 62 to 72% from OF. The corresponding lower heating value range of sampled gases were 11.8-19.1 and 18.2-21.0 MJ m -3 , respectively.

Solar photocatalytic gas-phase degradation of n-decane--a comparative study using cellulose acetate monoliths coated with P25 or sol-gel TiO₂ films.

PubMed

Miranda, Sandra M; Lopes, Filipe V S; Rodrigues-Silva, Caio; Martins, Susana D S; Silva, Adrián M T; Faria, Joaquim L; Boaventura, Rui A R; Vilar, Vítor J P

2015-01-01

Cellulose acetate monoliths (CAM) were used as the substrate for the deposition of TiO2 films to produce honeycombed photoactive structures to fill a tubular photoreactor equipped with a compound parabolic collector. By using such a setup, an efficient single-pass gas-phase conversion was achieved in the degradation of n-decane, a model volatile organic compound. The CAM three-dimensional, gas-permeable transparent structure with a rugged surface enables a good adhesion of the catalytic coating. It also provides a rigid structure for packing the tubular photoreactor, and maximizing the illuminated catalyst surface. The efficiency of the photocatalytic oxidation (PCO) process on n-decane degradation was evaluated under different operating conditions, such as feeding concentration (73 and 146 ppm), gas stream flow rate (73, 150, and 300 mL min(-1)), relative humidity (3 and 25 %), and UV irradiance (18.9, 29.1, and 38.4 WUV m(-2)). The results show that n-decane degradation by neat photolysis is negligible, but mineralization efficiencies of 86 and 82 % were achieved with P25-CAM and SG-CAM, respectively, for parent pollutant conversions above 95 %, under steady-state conditions. A mass transfer model, considering the mass balance to the plug-flow packed photoreactor, and PCO reaction given by a Langmuir-Hinshelwood bimolecular non-competitive two types of sites equation, was able to predict well the PCO kinetics under steady-state conditions, considering all the operational parameters tested. Overall, the performance of P25-CAM was superior taking into account mineralization efficiency, cost of preparation, surface roughness, and robustness of the deposited film.

Direct gas-solid carbonation kinetics of steel slag and the contribution to in situ sequestration of flue gas CO(2) in steel-making plants.

PubMed

Tian, Sicong; Jiang, Jianguo; Chen, Xuejing; Yan, Feng; Li, Kaimin

2013-12-01

Direct gas-solid carbonation of steel slag under various operational conditions was investigated to determine the sequestration of the flue gas CO2 . X-ray diffraction analysis of steel slag revealed the existence of portlandite, which provided a maximum theoretical CO2 sequestration potential of 159.4 kg CO 2 tslag (-1) as calculated by the reference intensity ratio method. The carbonation reaction occurred through a fast kinetically controlled stage with an activation energy of 21.29 kJ mol(-1) , followed by 10(3) orders of magnitude slower diffusion-controlled stage with an activation energy of 49.54 kJ mol(-1) , which could be represented by a first-order reaction kinetic equation and the Ginstling equation, respectively. Temperature, CO2 concentration, and the presence of SO2 impacted on the carbonation conversion of steel slag through their direct and definite influence on the rate constants. Temperature was the most important factor influencing the direct gas-solid carbonation of steel slag in terms of both the carbonation conversion and reaction rate. CO2 concentration had a definite influence on the carbonation rate during the kinetically controlled stage, and the presence of SO2 at typical flue gas concentrations enhanced the direct gas-solid carbonation of steel slag. Carbonation conversions between 49.5 % and 55.5 % were achieved in a typical flue gas at 600 °C, with the maximum CO2 sequestration amount generating 88.5 kg CO 2 tslag (-1) . Direct gas-solid carbonation of steel slag showed a rapid CO2 sequestration rate, high CO2 sequestration amounts, low raw-material costs, and a large potential for waste heat utilization, which is promising for in situ carbon capture and sequestration in the steel industry. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Laser induced fluorescence in nanosecond repetitively pulsed discharges for CO2 conversion

NASA Astrophysics Data System (ADS)

Martini, L. M.; Gatti, N.; Dilecce, G.; Scotoni, M.; Tosi, P.

2018-01-01

A CO2 nanosecond repetitively pulsed discharge (NRP) is a harsh environment for laser induced fluorescence (LIF) diagnostics. The difficulties arise from it being a strongly collisional system in which the gas composition, pressure and temperature, have quick and strong variations. The relevant diagnostic problems are described and illustrated through the application of LIF to the measurement of the OH radical in three different discharge configurations, with gas mixtures containing CO2 + H2O. These range from a dielectric barrier NRP with He buffer gas, a less hostile case in which absolute OH density measurement is possible, to an NRP in CO2+H2O, where the full set of drawbacks is at work. In the last case, the OH density measurement is not possible with laser pulses and detector time resolution in the ns time scale. Nevertheless, it is shown that with a proper knowledge of the collisional rate constants involved in the LIF process, a collisional energy transfer-LIF methodology is still applicable to deduce the gas composition from the analysis of LIF spectra.

Study on systems based on coal and natural gas for producing dimethyl ether

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

Zhou, L.; Hu, S.Y.; Chen, D.J.

2009-04-15

China is a coal-dependent country and will remain so for a long time. Dimethyl ether (DME), a potential substitute for liquid fuel, is a kind of clean diesel motor fuel. The production of DME from coal is meaningful and is studied in this article. Considering the C/H ratios of coal and natural gas (NG), the cofeed (coal and NG) system (CFS), which does not contain the water gas shift process, is studied. It can reduce CO{sub 2} emission and increase the conversion rate of carbon, producing more DME. The CFS is simulated and compared with the coal-based and NG-based systemsmore » with different recycling ratios. The part of the exhaust gas that is not recycled is burned, producing electricity. On the basis of the simulation results, the thermal efficiency, economic index, and CO{sub 2} emission ratio are calculated separately. The CFS with a 100% recycling ratio has the best comprehensive evaluation index, while the energy, economy, and environment were considered at the same time.« less

Quantification of OH and HO2 radicals during the low-temperature oxidation of hydrocarbons by Fluorescence Assay by Gas Expansion technique

PubMed Central

Blocquet, Marion; Schoemaecker, Coralie; Amedro, Damien; Herbinet, Olivier; Battin-Leclerc, Frédérique; Fittschen, Christa

2013-01-01

•OH and •HO2 radicals are known to be the key species in the development of ignition. A direct measurement of these radicals under low-temperature oxidation conditions (T = 550–1,000 K) has been achieved by coupling a technique named fluorescence assay by gas expansion, an experimental technique designed for the quantification of these radicals in the free atmosphere, to a jet-stirred reactor, an experimental device designed for the study of low-temperature combustion chemistry. Calibration allows conversion of relative fluorescence signals to absolute mole fractions. Such radical mole fraction profiles will serve as a benchmark for testing chemical models developed to improve the understanding of combustion processes. PMID:24277836

The viking biological investigation: preliminary results.

PubMed

Klein, H P; Horowitz, N H; Levin, G V; Oyama, V I; Lederberg, J; Rich, A; Hubbard, J S; Hobby, G L; Straat, P A; Berdahl, B J; Carle, G C; Brown, F S; Johnson, R D

1976-10-01

Three different types of biological experiments on samples of martian surface material ("soil") were conducted inside the Viking lander. In the carbon assimilation or pyrolytic release experiment, (14)CO(2) and (14)CO were exposed to soil in the presence of light. A small amount of gas was found to be converted into organic material. Heat treatment of a duplicate sample prevented such conversion. In the gas exchange experiment, soil was first humidified (exposed to water vapor) for 6 sols and then wet with a complex aqueous solution of metabolites. The gas above the soil was monitored by gas chromatography. A substantial amount of O(2) was detected in the first chromatogram taken 2.8 hours after humidification. Subsequent analyses revealed that significant increases in CO(2) and only small changes in N(2) had also occurred. In the labeled release experiment, soil was moistened with a solution containing several (14)C-labeled organic compounds. A substantial evolution of radioactive gas was registered but did not occur with a duplicate heat-treated sample. Alternative chemical and biological interpretations are possible for these preliminary data. The experiments are still in process, and these results so far do not allow a decision regarding the existence of life on the plonet Mars.

A Quantitative Real-Time PCR-Based Strategy for Molecular Evaluation of Nicotine Conversion in Burley Tobacco.

PubMed

Sun, Bo; Xue, Sheng-Ling; Zhang, Fen; Luo, Zhao-Peng; Wu, Ming-Zhu; Chen, Qing; Tang, Hao-Ru; Lin, Fu-Cheng; Yang, Jun

2015-11-17

Nornicotine production in Nicotiana tabacum is undesirable because it is the precursor of the carcinogen N'-nitrosonornicotine. In some individual burley tobacco plants, a large proportion of the nicotine can be converted to nornicotine, and this process of nicotine conversion is mediated primarily by enzymatic N-demethylation of nicotine which is controlled mainly by CYP82E4. Here we report a novel strategy based on quantitative real-time polymerase chain reaction (qPCR) method, which analyzed the ratio of nicotine conversion through examining the transcript level of CYP82E4 in burley leaves and do not need ethylene induction before detected. The assay was linear in a range from 1 × 10¹ to 1 × 10⁵ copies/mL of serially diluted standards, and also showed high specificity and reproducibility (93%-99%). To assess its applicability, 55 plants of burley cultivar Ky8959 at leaf maturing stage were analyzed, and the results were in accordance with those from gas chromatograph-mass spectrometry (GC-MS) method. Moreover, a linear correlation existed between conversion level and CYP82E4 transcript abundance. Taken together, the quantitative real-time PCR assay is standardized, rapid and reproducible for estimation of nicotine conversion level in vivo, which is expected to shed new light on monitoring of burley tobacco converter.

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

Warren, B.K.; Campbell, K.D.

Methane oxidative coupling studies were carried out in an atmospheric quartz reactor at temperatures between 700 and 800/degree/C. New catalysts prepared and studied included doped alkaline earth catalysts, lanthanide oxides, and proprietary catalysts. Neodymium oxide, Nd/sub 2/O/sub 3/, was found to be as active and selective as samarium oxide, Sm/sub 2/O/sub 3/, in contrast to literature reports. Proprietary Union Carbide catalysts (UCC-S:1) showed initial methane conversions and C/sub 2/ selectivities comparable to literature catalysts. Atypically low carbon dioxide to carbon monoxide ratios (typically ten times lower than those seen in the literature or other catalysts tested) and high ethylene tomore » ethane ratios (3 to 6 compared to typical literature ratios below 1) were obtained. These results are interesting because ethylene is more valuable than ethane and carbon monoxide is more valuable than carbon dioxide. With these UCC-S:1 catalysts, rapid deactivation was coupled with an observed shift in product ratios toward those more typical in the literature. Initial cases for process conceptualization studies were selected. The Comparison Case will consist of the conversion sequence from methane to synthesis gas to methanol to olefins to liquid hydrocarbon fuels. Case 1 will consist of the conversion of methane to ethylene and ethane. Case 2 will be the direct conversion of methane to C/sub 2/'s followed by conversion to liquid hydrocarbon fuels. 7 figs., 18 tabs.« less

The Effects of Voltage and Concentration of Sodium Bicarbonate on Electrochemical Synthesis of Ethanol from Carbon Dioxide Using Brass as Cathode

NASA Astrophysics Data System (ADS)

Ramadan, Septian; Fariduddin, Sholah; Rizki Aminudin, Afianti; Kurnia Hayatri, Antisa; Riyanto

2017-11-01

The effects of voltage and concentration of sodium bicarbonate were investigated to determine the optimum conditions of the electrochemical synthesis process to convert carbon dioxide into ethanol. The conversion process is carried out using a sodium bicarbonate electrolyte solution in an electrochemical synthesis reactor equipped with a cathode and anode. As the cathode was used brass, while as the anode carbon was utilized. Sample of the electrochemical synthesis process was analyzed by gas chromatography to determine the content of the compounds produced. The optimum electrochemical synthesis conditions to convert carbon dioxide into ethanol are voltage and concentration of sodium bicarbonate are 3 volts and 0.4 M with ethanol concentration of 1.33%.

Investigation of hydrogenation of toluene to methylcyclohexane in a trickle bed reactor by low-field nuclear magnetic resonance spectroscopy.

PubMed

Guthausen, Gisela; von Garnier, Agnes; Reimert, Rainer

2009-10-01

Low-field nuclear magnetic resonance (NMR) spectroscopy is applied to study the hydrogenation of toluene in a lab-scale reactor. A conventional benchtop NMR system was modified to achieve chemical shift resolution. After an off-line validity check of the approach, the reaction product is analyzed on-line during the process, applying chemometric data processing. The conversion of toluene to methylcyclohexane is compared with off-line gas chromatographic analysis. Both classic analytical and chemometric data processing was applied. As the results, which are obtained within a few tens of seconds, are equivalent within the experimental accuracy of both methods, low-field NMR spectroscopy was shown to provide an analytical tool for reaction characterization and immediate feedback.

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

Abboud, Alexander; Guillen, Donna Post; Pokorny, Richard

At the Hanford site in the state of Washington, more than 56 million gallons of radioactive waste is stored in underground tanks. The cleanup plan for this waste is vitrification at the Waste Treatment Plant (WTP), currently under construction. At the WTP, the waste will be blended with glass-forming materials and heated to 1423K, then poured into stainless steel canisters to cool and solidify. A fundamental understanding of the glass batch melting process is needed to optimize the process to reduce cost and decrease the life cycle of the cleanup effort. The cold cap layer that floats on the surfacemore » of the glass melt is the primary reaction zone for the feed-to-glass conversion. The conversion reactions include water release, melting of salts, evolution of batch gases, dissolution of quartz and the formation of molten glass. Obtaining efficient heat transfer to this region is crucial to achieving high rates of glass conversion. Computational fluid dynamics (CFD) modeling is being used to understand the heat transfer dynamics of the system and provide insight to optimize the process. A CFD model was developed to simulate the DM1200, a pilot-scale melter that has been extensively tested by the Vitreous State Laboratory (VSL). Electrodes are built into the melter to provide Joule heating to the molten glass. To promote heat transfer from the molten glass into the reactive cold cap layer, bubbling of the molten glass is used to stimulate forced convection within the melt pool. A three-phase volume of fluid approach is utilized to model the system, wherein the molten glass and cold cap regions are modeled as separate liquid phases, and the bubbling gas and plenum regions are modeled as one lumped gas phase. The modeling of the entire system with a volume of fluid model allows for the prescription of physical properties on a per-phase basis. The molten glass phase and the gas phase physical properties are obtained from previous experimental work. Finding representative properties for the cold cap region is more difficult, as this region is not a true liquid, but rather a multilayer region consisting of a porous and a foamy layer. Physical properties affecting heat transfer, namely the thermal conductivity and heat capacity, have been fit to closely match data and observations from laboratory experiments. Data from xray tomography and quenching of laboratory-scale cold caps provide insight into the topology of bubble distribution within the cold cap at various temperatures. Heat transfer within the melter was validated by comparison with VSL data for the pilot-scale melter.« less

Plasma-assisted CO2 conversion: optimizing performance via microwave power modulation

NASA Astrophysics Data System (ADS)

Britun, Nikolay; Silva, Tiago; Chen, Guoxing; Godfroid, Thomas; van der Mullen, Joost; Snyders, Rony

2018-04-01

Significant improvement in the energy efficiency of plasma-assisted CO2 conversion is achieved with applied power modulation in a surfaguide microwave discharge. The obtained values of CO2 conversion and energy efficiency are, respectively, 0.23 and 0.33 for a 0.95 CO2  +  0.05 N2 gas mixture. Analysis of the energy relaxation mechanisms shows that power modulation can potentially affect the vibrational-translational energy exchange in plasma. In our case, however, this mechanism does not play a major role, likely due to the low degree of plasma non-equilibrium in the considered pressure range. Instead, the gas residence time in the discharge active zone together with plasma pulse duration are found to be the main factors affecting the CO2 conversion efficiency at low plasma pulse repetition rates. This effect is confirmed experimentally by the in situ time-resolved two-photon absorption laser-induced fluorescence measurements of CO molecular density produced in the discharge as a result of CO2 decomposition.

Plasma catalytic reforming of methane

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

Bromberg, L.; Cohn, D.R.; Rabinovich, A.

1998-08-01

Thermal plasma technology can be efficiently used in the production of hydrogen and hydrogen-rich gases from methane and a variety of fuels. This paper describes progress in plasma reforming experiments and calculations of high temperature conversion of methane using heterogeneous processes. The thermal plasma is a highly energetic state of matter that is characterized by extremely high temperatures (several thousand degrees Celsius) and high degree of dissociation and substantial degree of ionization. The high temperatures accelerate the reactions involved in the reforming process. Hydrogen-rich gas (50% H{sub 2}, 17% CO and 33% N{sub 2}, for partial oxidation/water shifting) can bemore » efficiently made in compact plasma reformers. Experiments have been carried out in a small device (2--3 kW) and without the use of efficient heat regeneration. For partial oxidation/water shifting, it was determined that the specific energy consumption in the plasma reforming processes is 16 MJ/kg H{sub 2} with high conversion efficiencies. Larger plasmatrons, better reactor thermal insulation, efficient heat regeneration and improved plasma catalysis could also play a major role in specific energy consumption reduction and increasing the methane conversion. A system has been demonstrated for hydrogen production with low CO content ({approximately} 1.5%) with power densities of {approximately} 30 kW (H{sub 2} HHV)/liter of reactor, or {approximately} 10 m{sup 3}/hr H{sub 2} per liter of reactor. Power density should further increase with increased power and improved design.« less

Application of Laser Plasma Sources of Soft X-rays and Extreme Ultraviolet (EUV) in Imaging, Processing Materials and Photoionization Studies

NASA Astrophysics Data System (ADS)

Fiedorowicz, H.; Bartnik, A.; Wachulak, P. W.; Jarocki, R.; Kostecki, J.; Szczurek, M.; Ahad, I. U.; Fok, T.; Szczurek, A.; Wȩgrzyński, Ł.

In the paper we present new applications of laser plasma sources of soft X-rays and extreme ultraviolet (EUV) in various areas of plasma physics, nanotechnology and biomedical engineering. The sources are based on a gas puff target irradiated with nanosecond laser pulses from commercial Nd: YAG lasers, generating pulses with time duration from 1 to 10 ns and energies from 0.5 to 10 J at a 10 Hz repetition rate. The targets are produced with the use of a double valve system equipped with a special nozzle to form a double-stream gas puff target which allows for high conversion efficiency of laser energy into soft X-rays and EUV without degradation of the nozzle. The sources are equipped with various optical systems to collect soft X-ray and EUV radiation and form the radiation beam. New applications of these sources in imaging, including EUV tomography and soft X-ray microscopy, processing of materials and photoionization studies are presented.