Biocatalytic Refining of Soybean Oil into Cosmeceutical Ingredients

USDA-ARS?s Scientific Manuscript database

Our mission is to develop new, value-added uses for commodity crops and oils. We chose to fulfill this mission while adhering as closely as possible to the tenants of “green” chemistry. We have developed patented, all-natural oils called Feruloyl Soy Glycerols (FSG) from the biocatalytic transester...

Microscale technology and biocatalytic processes: opportunities and challenges for synthesis.

PubMed

Wohlgemuth, Roland; Plazl, Igor; Žnidaršič-Plazl, Polona; Gernaey, Krist V; Woodley, John M

2015-05-01

Despite the expanding presence of microscale technology in chemical synthesis and energy production as well as in biomedical devices and analytical and diagnostic tools, its potential in biocatalytic processes for pharmaceutical and fine chemicals, as well as related industries, has not yet been fully exploited. The aim of this review is to shed light on the strategic advantages of this promising technology for the development and realization of biocatalytic processes and subsequent product recovery steps, demonstrated with examples from the literature. Constraints, opportunities, and the future outlook for the implementation of these key green engineering methods and the role of supporting tools such as mathematical models to establish sustainable production processes are discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biocatalytic Conversion of Avermectin to 4"-Oxo-Avermectin: Characterization of Biocatalytically Active Bacterial Strains and of Cytochrome P450 Monooxygenase Enzymes and Their Genes

PubMed Central

Jungmann, Volker; Molnár, István; Hammer, Philip E.; Hill, D. Steven; Zirkle, Ross; Buckel, Thomas G.; Buckel, Dagmar; Ligon, James M.; Pachlatko, J. Paul

2005-01-01

4"-Oxo-avermectin is a key intermediate in the manufacture of the agriculturally important insecticide emamectin benzoate from the natural product avermectin. Seventeen biocatalytically active Streptomyces strains with the ability to oxidize avermectin to 4"-oxo-avermectin in a regioselective manner have been discovered in a screen of 3,334 microorganisms. The enzymes responsible for this oxidation reaction in these biocatalytically active strains were found to be cytochrome P450 monooxygenases (CYPs) and were termed Ema1 to Ema17. The genes for Ema1 to Ema17 have been cloned, sequenced, and compared to reveal a new subfamily of CYPs. Ema1 to Ema16 have been overexpressed in Escherichia coli and purified as His-tagged recombinant proteins, and their basic enzyme kinetic parameters have been determined. PMID:16269732

Flue gas desulfurization gypsum agricultural network alabama (cotton)

USDA-ARS?s Scientific Manuscript database

Flue gas desulfurization gypsum (FGDG) is an excellent source of gypsum (CaSO4•2H2O) that can be beneficially used in agriculture. Research was conducted as part of the Flue Gas Desulfurization Gypsum Agricultural Network program sponsored by the Electric Power Research Institute in collaboration wi...

Plane flame furnace combustion tests on JPL desulfurized coal

NASA Technical Reports Server (NTRS)

Reuther, J. J.; Kim, H. T.; Lima, J. G. H.

1982-01-01

The combustion characteristics of three raw bituminous (PSOC-282 and 276) and subbituminous (PSOC-230) coals, the raw coals partially desulfurized (ca -60%) by JPL chlorinolysis, and the chlorinated coals more completely desulfurized (ca -75%) by JPL hydrodesulfurization were determined. The extent to which the combustion characteristics of the untreated coals were altered upon JPL sulfur removal was examined. Combustion conditions typical of utility boilers were simulated in the plane flame furnace. Upon decreasing the parent coal voltaile matter generically by 80% and the sulfur by 75% via the JPL desulfurization process, ignition time was delayed 70 fold, burning velocity was retarded 1.5 fold, and burnout time was prolonged 1.4 fold. Total flame residence time increased 2.3 fold. The JPL desulfurization process appears to show significant promise for producing technologically combustible and clean burning (low SO3) fuels.

Biocatalytic site- and enantioselective oxidative dearomatization of phenols

NASA Astrophysics Data System (ADS)

Baker Dockrey, Summer A.; Lukowski, April L.; Becker, Marc R.; Narayan, Alison R. H.

2018-02-01

The biocatalytic transformations used by chemists are often restricted to simple functional-group interconversions. In contrast, nature has developed complexity-generating biocatalytic reactions within natural product pathways. These sophisticated catalysts are rarely employed by chemists, because the substrate scope, selectivity and robustness of these catalysts are unknown. Our strategy to bridge the gap between the biosynthesis and synthetic chemistry communities leverages the diversity of catalysts available within natural product pathways. Here we show that, starting from a suite of biosynthetic enzymes, catalysts with complementary substrate scope as well as selectivity can be identified. This strategy has been applied to the oxidative dearomatization of phenols, a chemical transformation that rapidly builds molecular complexity from simple starting materials and cannot be accomplished with high selectivity using existing catalytic methods. Using enzymes from biosynthetic pathways, we have successfully developed a method to produce ortho-quinol products with controlled site- and stereoselectivity. Furthermore, we have capitalized on the scalability and robustness of this method in gram-scale reactions as well as multi-enzyme and chemoenzymatic cascades.

Effect of Silicon on Desulfurization of Aluminum-killed Steels

NASA Astrophysics Data System (ADS)

Roy, Debdutta

Recent reports have suggested that silicon has a beneficial effect on the rate of desulfurization of Al-killed steel. This effect is difficult to understand looking at the overall desulfurization reaction which does not include silicon. However an explanation is proposed by taking into account the (SiO2)/[Si] equilibrium in which some Al reaching the slag-metal interface is used in reducing the SiO2 in the slag. This reaction can be suppressed to some extent if the silicon content of the metal is increased and in doing so, more Al will be available at the slag-metal interface for the desulfurization reaction and this would increase the rate of the desulfurization reaction. A model was developed, assuming the rates are controlled by mass transfer, taking into account the coupled reactions of the reduction of silica, and other unstable oxides, namely iron oxide and manganese oxide, in the slag and desulfurization reaction in the steel by aluminum. The model predicts that increasing silicon increases the rate and extent of desulfurization. Plant data was analyzed to obtain rough estimates of ladle desulfurization rates and also used to validate the model predictions. Experiments have been conducted on a kilogram scale of material in an induction furnace to test the hypothesis. The major conclusions of the study are as follows: The rate and extent of desulfurization improve with increasing initial silicon content in the steel; the effect diminishes at silicon contents higher than approximately 0.2% and with increasing slag basicity. This was confirmed with kilogram-scale laboratory experiments. The effects of the silicon content in the steel (and of initial FeO and MnO in the slag) largely arise from the dominant effects of these reactions on the equilibrium aluminum content of the steel: as far as aluminum consumption or pick-up is concerned, the Si/SiO2 reaction dominates, and desulfurization has only a minor effect on aluminum consumption. The rate is primarily

Desulfurization of Saudi Arabian crudes by oxidation-extraction method.

PubMed

Al Otaibi, Raja L; Liu, Dong; Hou, Xulian; Song, Linhua; Li, Qingyin; Li, Mengfei; Almigrin, Hamid O; Yan, Zifeng

The oxidation-extraction desulfurization of Saudi Arabian crudes was conducted with hydrogen peroxide-acetic acid oxidation system. The selection of extractant, the optimization of oxidation-extraction conditions, and the exploration of desulfurization mechanism were studied. As DMF was used as the extractant, the optimal desulfurization rate of 35.11 % and oil recovery of 95 % were obtained at 70 °C with the molar ratio of peracetic acid to sulfur of 8:1, the molar ratio of acetic acid to hydrogen peroxide of 2:1 and the volume ratio of extractant to oil of 1:1. The desulfurization effect of different fractions in the treated Saudi Arabian crudes was found to obey the following order: gasoline-diesel fraction >VGO fraction >VR fraction, due to different types and structures of sulfur compounds. The oil quality was less affected and most sulfides were mainly extracted via DMF.

Radiation methods for demercaptanization and desulfurization of oil products

NASA Astrophysics Data System (ADS)

Zaykina, R. F.; Zaykin, Yu. A.; Mamonova, T. B.; Nadirov, N. K.

2002-03-01

A two-stage method for the desulfurization of oil is presented. The first stage strongly oxidizes sulfuric material to do away with its chemical aggressiveness and promote its removal. Desulfurization of the overall product is reached at the second stage by means of conventional methods.

Biocatalytic separation of N-7/N-9 guanine nucleosides.

PubMed

Singh, Sunil K; Sharma, Vivek K; Olsen, Carl E; Wengel, Jesper; Parmar, Virinder S; Prasad, Ashok K

2010-11-19

Vorbrüggen coupling of trimethylsilylated 2-N-isobutanoylguanine with peracetylated pentofuranose derivatives generally gives inseparable N-7/N-9 glycosyl mixtures. We have shown that the two isomers can be separated biocatalytically by Novozyme-435-mediated selective deacetylation of the 5'-O-acetyl group of peracetylated N-9 guanine nucleosides.

Effect of calcium formate as an additive on desulfurization in power plants.

PubMed

Li, Zhenhua; Xie, Chunfang; Lv, Jing; Zhai, Ruiguo

2018-05-01

SO 2 in flue gas needs to be eliminated to alleviate air pollution. As the quality of coal decreases and environmental standard requirements become more stringent, the high-efficiency desulfurization of flue gas faces more and more challenges. As an economical and environmentally friendly solution, the effect of calcium formate as an additive on desulfurization efficiency in the wet flue gas desulfurization (WFGD) process was studied for the first time. Improvement of the desulfurization efficiency was achieved with limited change in pH after calcium formate was added into the reactor, and it was found to work better than other additives tested. The positive effects were further verified in a power plant, which showed that adding calcium formate could promote the dissolution of calcium carbonate, accelerate the growth of gypsum crystals and improve the efficiency of desulfurization. Thus, calcium formate was proved to be an effective additive and can potentially be used to reduce the amount of limestone slurry required, as well as the energy consumption and operating costs in industrial desulfurization. Copyright © 2017. Published by Elsevier B.V.

Irradiation pretreatment for coal desulfurization

NASA Technical Reports Server (NTRS)

Hsu, G. C.

1979-01-01

Process using highly-penetrating nuclear radiation (Beta and Gamma radiation) from nuclear power plant radioactive waste to irradiate coal prior to conventional desulfurization procedures increases total extraction of sulfur.

Enzyme-polymer composites with high biocatalytic activity and stability

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

Kim, Jungbae; Kosto, Timothy J.; Manimala, Joseph C.

2004-08-22

We have applied vacuum-spraying and electrospinning to incorporate an enzyme into a polymer matrix, creating a novel and highly active biocatalytic composite. As a unique technical approach, enzymes were co-dissolved in toluene with polymers, and the solvent was then rapidly removed by injecting the mixture into a vacuum chamber or by electrospinning. Subsequent crosslinking of the enzyme with glutaraldehyde resulted in stable entrapped enzyme within the polymeric matrices. For example, an amorphous composite of alpha-chymotrypsin and polyethylene showed no significant loss of enzymatic activity in aqueous buffer for one month. Nanofibers of alpha-chymotrypsin and polystyrene also showed no decrease inmore » activity for more than two weeks. The normalized activity of amorphous composite in organic solvents was 3-13 times higher than that of native alpha-chymotrypsin. The activity of nanofibers was 5-7 times higher than that of amorphous composite in aqueous buffer solution. The composites of alpha-chymotrypsin and polymers demonstrate the feasibility of obtaining a wide variety of active and stable biocatalytic materials with many combinations of enzymes and polymers.« less

Ultrasound-assisted oxidative desulfurization of bitumen

NASA Astrophysics Data System (ADS)

Kamal, Wan Mohamad Ikhwan bin Wan; Okawa, Hirokazu; Kato, Takahiro; Sugawara, Katsuyasu

2017-07-01

Bitumen contains a high percentage of sulfur (about 4.6 wt %). A hydrodesulfurization method is used to remove sulfur from bitumen. The drawback of this method is the requirement for a high temperature of >300 °C. Most of the sulfur in bitumen exists as thiophene. Oxidative desulfurization (ODS), involving oxidizing sulfur using H2O2, then removing it using NaOH, allows the removal of sulfur in thiophene at low temperatures. We removed sulfur from bitumen using ODS treatment under ultrasound irradiation, and 52% of sulfur was successfully removed. Additionally, the physical action of ultrasound assisted the desulfurization of bitumen, even at low H2O2 concentrations.

Synthesis and application of different phthalocyanine molecular sieve catalyst for oxidative desulfurization

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

Zhao, Na; Li, Siwen; Wang, Jinyi

2015-05-15

M{sub 2}(PcAN){sub 2} (M=Fe, Co, Ni, Cu, Zn and Mn) anchored onto W-HZSM-5 (M{sub 2}(PcAN){sub 2}–W-HZSM-5) or the M{sub 2}(PcTN){sub 2} doping W-HZSM-5 (M{sub 2}(PcTN){sub 2}/W-HZSM-5) were prepared and their catalytic performances were tested for oxidative desulfurization in the presence of oxygen. Thiophene (T), benzothiophene (BT), and dibenzothiophene (DBT) were considered as sulfur compounds. Among zeolite-based catalysts, the Cu{sub 2}(PcAN){sub 2}–W-HZSM-5 and Cu{sub 2}(PcTN){sub 2}/W-HZSM-5 showed superior desulfurization performance and the activity of selectivity followed the order: T>BT>DBT. The effects of phthalocyanine concentration were studied by UV–Vis and calcination temperature was obtained by TG-DSC for Cu{sub 2}(PcTN){sub 2}/W-HZSM-5. Catalysts weremore » characterized by EA, IR, XRD, SEM, TEM, ICP, and N{sub 2} adsorption. Reaction time, temperature and the amount of catalyst were investigated as the important parameters for optimization of the reaction. Furthermore, a possible process of oxidative desulfurization and the reaction products were proposed. - Graphical abstract: The ODS reaction schematic shows the reaction mechanism of ultra-deep desulfurization. The sulfur compounds are oxidized to their corresponding sulfoxides or sulfones through the use of oxygen and catalysts. The reaction process of ultra-deep desulfurization. - Highlights: • A kind of novel catalyst for deep desulfurization was synthesized. • Cu{sub 2}(PcAN){sub 2}–W-HZSM-5 exhibits excellent catalytic performance for desulfurization. • The reaction conditions that affect desulfurization efficiency are investigated. • The reaction process of model sulfur compounds is proposed.« less

Desulfurization: Critical step towards enhanced selenium removal from industrial effluents.

PubMed

Staicu, Lucian C; Morin-Crini, Nadia; Crini, Grégorio

2017-04-01

Selenium (Se) removal from synthetic solutions and from real Flue Gas Desulfurization (FGD) wastewater generated by a coal-fired power plant was studied for the first time using a commercial iron oxide impregnated strong base anion exchange resin, Purolite ® FerrIX A33E. In synthetic solutions, the resin showed high affinity for selenate and selenite, while sulfate exhibited a strong competition for both oxyanions. The FGD wastewater investigated is a complex system that contains Se (∼1200 μg L -1 ), SO 4 2- (∼1.1 g L -1 ), Cl - (∼9.5 g L -1 ), and Ca 2+ (∼5 g L -1 ), alongside a broad spectrum of toxic trace metals including Cd, Cr, Hg, Ni, and Zn. The resin performed poorly against Se in the raw FGD wastewater and showed moderate to good removal of several trace elements such as Cd, Cr, Hg, and Zn. In FGD effluent, sulfate was identified as a powerful competing anion for Se, having high affinity for the exchange active sites of the resin. The desulfurization of the FGD effluent using BaCl 2 led to the increase in Se removal from 3% (non-desulfurized effluent) to 80% (desulfurized effluent) by combined precipitation and ion exchange treatment. However, complete desulfurization using equimolar BaCl 2 could not be achieved due to the presence of bicarbonate that acts as a sulfate competitor for barium. In addition to selenium and sulfate removal, several toxic metals were efficiently removed (Cd: 91%; Cr: 100%; Zn: 99%) by the combined (desulfurization and ion exchange) treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Coal desulfurization by low temperature chlorinolysis, phase 3

NASA Technical Reports Server (NTRS)

Kalvinskas, J. J.; Rohatgi, N. K.; Ernest, J.

1981-01-01

Laboratory scale, bench scale batch reactor, and minipilot plant tests were conducted on 22 bituminous, subbituminous, and lignite coals. Chemical pretreatment and post treatment of coals relative to the chlorination were tried as a means of enhancing desulfurization by the chlorinolysis process. Elevated temperature (500-700 C) hydrogen treatment of chlorinolysis-processed coal at atmospheric pressure was found to substantially increase coal desulfurization up to 90 percent. Sulfur forms, proximate and ultimate analyses of the processed coal are included. Minipilot plant operation indicates that the continuous flow reactor provides coal desulfurization results comparable to those obtained in the batch reactor. Seven runs were conducted at coal feed rates of 1.5 to 8.8 kg per hour using water and methylchloroform solvents, gaseous chlorine feed of 3 to 31.4 SCFH at 21 to 70 C, and atmospheric pressure for retention times of 20 to 120 minutes.

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.

Biocatalytic Self-Assembly on Magnetic Nanoparticles.

PubMed

Conte, Maria P; Sahoo, Jugal Kishore; Abul-Haija, Yousef M; Lau, K H Aaron; Ulijn, Rein V

2018-01-24

Combining (bio)catalysis and molecular self-assembly provides an effective approach for the production and processing of self-assembled materials by exploiting catalysis to direct the assembly kinetics and hence controlling the formation of ordered nanostructures. Applications of (bio)catalytic self-assembly in biologically interfacing systems and in nanofabrication have recently been reported. Inspired by self-assembly in biological cells, efforts to confine catalysts on flat or patterned surfaces to exert spatial control over molecular gelator generation and nanostructure self-assembly have also emerged. Building on our previous work in the area, we demonstrate in this report the use of enzymes immobilized onto magnetic nanoparticles (NPs) to spatially localize the initiation of peptide self-assembly into nanofibers around NPs. The concept is generalized for both an equilibrium biocatalytic system that forms stable hydrogels and a nonequilibrium system that normally has a preset lifetime. Characterization of the hydrogels shows that self-assembly occurs at the site of enzyme immobilization on the NPs to give rise to gels with a "hub-and-spoke" morphology, where the nanofibers are linked through the enzyme-NP conjugates. This NP-controlled arrangement of self-assembled nanofibers enables both remarkable enhancements in the shear strength of hydrogel systems and a dramatic extension of the hydrogel stability in the nonequilibrium system. We are also able to show that the use of magnetic NPs enables the external control of both the formation of the hydrogel and its overall structure by application of an external magnetic field. We anticipate that the enhanced properties and stimuli-responsiveness of our NP-enzyme system will have applications ranging from nanomaterial fabrication to biomaterials and biosensing.

Flue Gas Desulfurization at Navy Bases, Navy Energy Guidance Study. Phase IV.

DTIC Science & Technology

1980-08-01

WA08O9 146 BECHTEL NATIONAL INC SAN FRANCISCO CA FLUE GAS DESULFURIZATION AT NAVY BASES, NAVY ENERGY GUIDANCE ST-ETC(U) AUG 80 A I MCCONE N68305-77C... Flue gas desulfurization 10. ABSTRACT (C lno d. It -.4..,.d id-1, by 61-hb n-.1..) A study o e availability, costs, and operating perfor- nce of...industral-sized flue gas desulfurization (FGD) systems or coal-fired boilers 4...- mrfmmed for-the Civil Englneering- , - boratory at the Naval Construction

Low-Cost Aqueous Coal Desulfurization

NASA Technical Reports Server (NTRS)

Kalvinskas, J. J.; Vasilakos, N.; Corcoran, W. H.; Grohmann, K.; Rohatgi, N. K.

1982-01-01

Water-based process for desulfurizing coal not only eliminates need for costly organic solvent but removes sulfur more effectively than an earlier solvent-based process. New process could provide low-cost commercial method for converting high-sulfur coal into environmentally acceptable fuel.

Desulfurization kinetics of molten copper by gas bubbling

NASA Astrophysics Data System (ADS)

Fukunaka, Y.; Nishikawa, K.; Sohn, H. S.; Asaki, Z.

1991-02-01

Molten copper with 0.74 wt pct sulfur content was desulfurized at 1523 K by bubbling Ar-O2 gas through a submerged nozzle. The reaction rate was significantly influenced not only by the oxygen partial pressure but also by the gas flow rate. Little evolution of SO2 gas was observed in the initial 10 seconds of the oxidation; however, this was followed by a period of high evolution rate of SO2 gas. The partial pressure of SO2 gas decreased with further progress of the desulfurization. The effect of the immersion depth of the submerged nozzle was negligible. The overall reaction is decomposed to two elementary reactions: the desulfurization and the dissolution rate of oxygen. The assumptions were made that these reactions are at equilibrium and that the reaction rates are controlled by mass transfer rates within and around the gas bubble. The time variations of sulfur and oxygen contents in the melt and the SO2 partial pressure in the off-gas under various bubbling conditions were well explained by the mathematical model combined with the reported thermodynamic data of these reactions. Based on the present model, it was anticipated that the oxidation rate around a single gas bubble was mainly determined by the rate of gas-phase mass transfer, but all oxygen gas blown into the melt was virtually consumed to the desulfurization and dissolution reactions before it escaped from the melt surface.

Study of variation grain size in desulfurization process of calcined petroleum coke

NASA Astrophysics Data System (ADS)

Pintowantoro, Sungging; Setiawan, Muhammad Arif; Abdul, Fakhreza

2018-04-01

Indonesia is a country with abundant natural resources, such as mineral mining and petroleum. In petroleum processing, crude oil can be processed into a source of fuel energy such as gasoline, diesel, oil, petroleum coke, and others. One of crude oil potentials in Indonesia is petroleum coke. Petroleum coke is a product from oil refining process. Sulfur reducing process in calcined petroleum cokes can be done by desulfurization process. The industries which have potential to become petroleum coke processing consumers are industries of aluminum smelting (anode, graphite block, carbon mortar), iron riser, calcined coke, foundry coke, etc. Sulfur reducing process in calcined petroleum coke can be done by thermal desulfurization process with alkaline substance NaOH. Desulfurization of petroleum coke process can be done in two ways, which are thermal desulfurization and hydrodesulphurization. This study aims to determine the effect of various grain size on sulfur, carbon, and chemical bond which contained by calcined petroleum coke. The raw material use calcined petroleum coke with 0.653% sulfur content. The grain size that used in this research is 50 mesh, then varied to 20 mesh and 100 mesh for each desulfurization process. Desulfurization are tested by ICP, UV-VIS, and FTIR to determine levels of sulfur, carbon, chemical bonding and sulfur dissolved water which contained in the residual washing of calcined petroleum coke. From various grain size that mentioned before, the optimal value is on 100 mesh grain size, where the sulfur content in petroleum coke is 0.24% and carbon content reaches the highest level of 97.8%. Meanwhile for grain size 100 mesh in the desulfurization process is enough to break the chemical bonds of organic sulfur in petroleum coke.

Novel biocatalytic systems for maintaining the nucleotide balance based on adenylate kinase immobilized on carbon nanostructures.

PubMed

Hetmann, Anna; Wujak, Magdalena; Bolibok, Paulina; Zięba, Wojciech; Wiśniewski, Marek; Roszek, Katarzyna

2018-07-01

In this study graphene oxide (GO), carbon quantum dots (CQD) and carbon nanoonions (CNO) have been characterized and applied for the first time as a matrix for recombinant adenylate kinase (AK, EC 2.7.4.3) immobilization. AK is an enzyme fulfilling a key role in metabolic processes. This phosphotransferase catalyzes the interconversion of adenine nucleotides (ATP, ADP and AMP) and thereby participates in nucleotide homeostasis, monitors a cellular energy charge as well as acts as a component of purinergic signaling system. The AK activity in all obtained biocatalytic systems was higher as compared to the free enzyme. We have found that the immobilization on carbon nanostructures increased both activity and stability of AK. Moreover, the biocatalytic systems consisting of AK immobilized on carbon nanostructures can be easily and efficiently lyophilized without risk of desorption or decrease in the catalytic activity of the investigated enzyme. The positive action of AK-GO biocatalytic system in maintaining the nucleotide balance in in vitro cell culture was proved. Copyright © 2018 Elsevier B.V. All rights reserved.

Multi-objective optimization of oxidative desulfurization in a sono-photochemical airlift reactor.

PubMed

Behin, Jamshid; Farhadian, Negin

2017-09-01

Response surface methodology (RSM) was employed to optimize ultrasound/ultraviolet-assisted oxidative desulfurization in an airlift reactor. Ultrasonic waves were incorporated in a novel-geometry reactor to investigate the synergistic effects of sono-chemistry and enhanced gas-liquid mass transfer. Non-hydrotreated kerosene containing sulfur and aromatic compounds was chosen as a case study. Experimental runs were conducted based on a face-centered central composite design and analyzed using RSM. The effects of two categorical factors, i.e., ultrasound and ultraviolet irradiation and two numerical factors, i.e., superficial gas velocity and oxidation time were investigated on two responses, i.e., desulfurization and de-aromatization yields. Two-factor interaction (2FI) polynomial model was developed for the responses and the desirability function associate with overlay graphs was applied to find optimum conditions. The results showed enhancement in desulfurization ability corresponds to more reduction in aromatic content of kerosene in each combination. Based on desirability approach and certain criteria considered for desulfurization/de-aromatization, the optimal desulfurization and de-aromatization yields of 91.7% and 48% were obtained in US/UV/O 3 /H 2 O 2 combination, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

Spray-dry desulfurization of flue gas from heavy oil combustion.

PubMed

Scala, Fabrizio; Lancia, Amedeo; Nigro, Roberto; Volpicelli, Gennaro

2005-01-01

An experimental investigation on sulfur dioxide removal in a pilot-scale spray dryer from the flue gas generated by combustion of low-sulfur (S) heavy oil is reported. A limewater slurry was sprayed through an ultrasonic two-fluid atomizer in the spray-dry chamber, and the spent sorbent was collected downstream in a pulse-jet baghouse together with fly ash. Flue gas was sampled at different points to measure the desulfurization efficiency after both the spray-dry chamber and the baghouse. Parametric tests were performed to study the effect of the following variables: gas inlet temperature, difference between gas outlet temperature and adiabatic saturation temperature, lime-to-S ratio, and average size of lime particles in the slurry. Results indicated that spray drying is an effective technology for the desulfurization of low-S fuel oil flue gas, provided operating conditions are chosen carefully. In particular, the lowest gas inlet and outlet temperatures compatible with baghouse operation should be selected, as should a sufficiently high lime-to-S ratio. The attainment of a small lime particle size in the slurry is critical for obtaining a high desulfurization efficiency. A previously presented spray-dry flue gas desulfurization model was used to simulate the pilot-scale desulfurization tests, to check the ability of the model to predict the S capture data and its usefulness as a design tool, minimizing the need for pilot-scale experimentation. Comparison between model and experimental results was fairly good for the whole range of calcium/S ratios considered.

Ralstonia eutropha as a biocatalyst for desulfurization of dibenzothiophene.

PubMed

Dejaloud, Azita; Vahabzadeh, Farzaneh; Habibi, Alireza

2017-07-01

The potential of Ralstonia eutropha as a biocatalyst for desulfurization of dibenzothiophene (DBT) was studied in growing and resting cell conditions. The results of both conditions showed that sulfur was removed from DBT which accompanied by the formation of 2-hydroxybiphenyl (2-HBP). In growing cell experiments, glucose was used as an energy supplying substrate in initial concentrations of 55 mM (energy-limited) and 111 mM (energy-sufficient). The growing cell behaviors were quantitatively described using the logistic equation and maintenance concept. The results indicated that 2-HBP production was higher for the energy-sufficient cultures, while the values of the specific growth rate and the maintenance coefficient for these media were lower than those of the energy-limited cultures. Additionally, the kinetic studies showed that the half-saturation constant for the energy-limited cultures was 2 times higher than the energy-sufficient ones where the inhibition constant (0.08 mM) and the maximum specific DBT desulfurization rate (0.002 mmol g cell -1  h -1 ) were almost constant. By defining desulfurizing capacity (D DBT ) including both the biomass concentration and time to reach a particular percentage of DBT conversion, the best condition for desulfurizing cell was determined at 23% g cell L -1  h -1 which corresponded with the resting cells that were harvested at the mid-exponential growth phase.

Two-stage coal gasification and desulfurization apparatus

DOEpatents

Bissett, Larry A.; Strickland, Larry D.

1991-01-01

The present invention is directed to a system which effectively integrates a two-stage, fixed-bed coal gasification arrangement with hot fuel gas desulfurization of a first stream of fuel gas from a lower stage of the two-stage gasifier and the removal of sulfur from the sulfur sorbent regeneration gas utilized in the fuel-gas desulfurization process by burning a second stream of fuel gas from the upper stage of the gasifier in a combustion device in the presence of calcium-containing material. The second stream of fuel gas is taken from above the fixed bed in the coal gasifier and is laden with ammonia, tar and sulfur values. This second stream of fuel gas is burned in the presence of excess air to provide heat energy sufficient to effect a calcium-sulfur compound forming reaction between the calcium-containing material and sulfur values carried by the regeneration gas and the second stream of fuel gas. Any ammonia values present in the fuel gas are decomposed during the combustion of the fuel gas in the combustion chamber. The substantially sulfur-free products of combustion may then be combined with the desulfurized fuel gas for providing a combustible fluid utilized for driving a prime mover.

Application of the desulfurization of phenothiazines for a sensitive detection method by high-performance liquid chromatography.

PubMed

Shimada, K; Mino, T; Nakajima, M; Wakabayashi, H; Yamato, S

1994-11-04

A simple and sensitive high-performance liquid chromatographic (HPLC) method for the determination of phenothiazine (PHE) is described. PHE is converted to diphenylamine (DIP) by desulfurization with Raney nickel catalyst. DIP is highly sensitive to electrochemical detection. The calibration graph for PHE quantification after desulfurization was linear between 0.1 and 2.0 ng per injection. The detection limit (signal-to-noise ratio = 3) of PHE after desulfurization was 10 pg, which is twenty times higher than that of the parent compound PHE. The proposed desulfurization technique was applied to other PHE-related compounds. The structural confirmation of the desulfurized product of PHE was carried out by LC-MS using atmospheric pressure chemical ionization.

Fluidized bed desulfurization

NASA Technical Reports Server (NTRS)

Ravindram, M.; Kallvinskas, J. J. (Inventor)

1985-01-01

High sulfur content carbonaceous material, such as coal is desulfurized by continuous fluidized suspension in a reactor with chlorine gas, inert dechlorinating gas and hydrogen gas. A source of chlorine gas, a source of inert gas and a source of hydrogen gas are connected to the bottom inlet through a manifold and a heater. A flow controler operates servos in a manner to continuously and sequentially suspend coal in the three gases. The sulfur content is reduced at least 50% by the treatment.

Simultaneous recovery and desulfurization of bitumen from oil sand using ultrasound irradiation

NASA Astrophysics Data System (ADS)

Okawa, Hirokazu; Kamal, Wan Mohamad Ikhwan bin Wan; Akazawa, Nobuyuki; Kato, Takahiro; Sugawara, Katsuyasu

2018-07-01

Oil sand contains bitumen, which includes a high percentage of sulfur. Before using bitumen as a fuel, it must be recovered from oil sand and desulfurized. Currently, bitumen is recovered from oil sand using hot water (<100 °C), and sulfur is removed via hydrodesulfurization (>300 °C). Both of these processes consume significant amounts of energy. In this study, we demonstrate the simultaneous recovery and desulfurization of bitumen from oil sand using oxidative desulfurization with ultrasonic irradiation and tetrahydrofuran at 20 °C. We successfully recovered 88% of the bitumen from oil sand and removed 42% of the sulfur from the bitumen.

Microbial desulfurization of coal

NASA Technical Reports Server (NTRS)

Dastoor, M. N.; Kalvinskas, J. J.

1978-01-01

Experiments indicate that several sulfur-oxidizing bacteria strains have been very efficient in desulfurizing coal. Process occurs at room temperature and does not require large capital investments of high energy inputs. Process may expand use of abundant reserves of high-sulfur bituminous coal, which is currently restricted due to environmental pollution. On practical scale, process may be integrated with modern coal-slurry transportation lines.

Evaluating the Development of Biocatalytic Technology for the Targeted Removal of Perchlorate from Drinking Water.

PubMed

Hutchison, Justin M; Guest, Jeremy S; Zilles, Julie L

2017-06-20

Removing micropollutants is challenging in part because of their toxicity at low concentrations. A biocatalytic approach could harness the high affinity of enzymes for their substrates to address this challenge. The potential of biocatalysis relative to mature (nonselective ion exchange, selective ion exchange, and whole-cell biological reduction) and emerging (catalysis) perchlorate-removal technologies was evaluated through a quantitative sustainable design framework, and research objectives were prioritized to advance economic and environmental sustainability. In its current undeveloped state, the biocatalytic technology was approximately 1 order of magnitude higher in cost and environmental impact than nonselective ion exchange. Biocatalyst production was highly correlated with cost and impact. Realistic improvement scenarios targeting biocatalyst yield, biocatalyst immobilization for reuse, and elimination of an electron shuttle could reduce total costs to $0.034 m -3 and global warming potential (GWP) to 0.051 kg CO 2 eq m -3 : roughly 6.5% of cost and 7.3% of GWP of the background from drinking water treatment and competitive with the best performing technology, selective ion exchange. With less stringent perchlorate regulatory limits, ion exchange technologies had increased cost and impact, in contrast to biocatalytic and catalytic technologies. Targeted advances in biocatalysis could provide affordable and sustainable treatment options to protect the public from micropollutants.

Differential desulfurization of dibenzothiophene by newly identified MTCC strains: Influence of Operon Array

PubMed Central

Bhanjadeo, Madhabi M.; Rath, Kalyani; Gupta, Dhirendra; Pradhan, Nilotpala; Biswal, Surendra K.; Mishra, Barada K.

2018-01-01

Since the sulfur specific cleavage is vital for the organic sulfur removal from fossil fuel, we explored potential bacterial strains of MTCC (Microbial Type Culture Collection) to desulfurize the Dibenzothiophene (DBT) through C-S bond cleavage (4-S pathway). MTCC strains Rhodococcus rhodochrous (3552), Arthrobacter sulfureus (3332), Gordonia rubropertincta (289), and Rhodococcus erythropolis (3951) capable of growing in 0.5 mM DBT were examined for their desulfurization ability. The presence of dsz genes as well as the metabolites was screened by polymerase chain reaction (PCR) and HPLC, respectively. All these strains showed > 99% DBT desulfurization with 10 days of incubation in minimal salt medium. From the HPLC analysis it was further revealed that these MTCC strains show differences in the end metabolites and desulfurize DBT differently following a variation in the regular 4-S pathway. These findings are also well corroborating with their respective organization of dszABC operons and their relative abundance. The above MTCC strains are capable of desulfurizing DBT efficiently and hence can be explored for biodesulfurization of petrochemicals and coal with an eco-friendly and energy economical process. PMID:29518089

Experimental Study on Semi-Dry Flue Gas Desulfurization Ash Used in Steel Slag Composite Material

NASA Astrophysics Data System (ADS)

Lu, Lijun; Fang, Honghui

This article carried out the experimental study on using desulfurization ash in steel slag composite material. This was done by investigating the desulfurization ash content in formula one and formula two samples on the influence of setting time and strength of mortar. Through this study the following conclusions were reached for formula one: (1) a setting time of more than 10 hours is required, (2) a dosage of desulfurization ash of 1 2% is optimal, where flexural strength is reduced by 10% 23% and compressive strength reduced by 5.7% 16.4%. The conclusions of formula two were: (1) when the dosage of desulfurization ash is within 5%, the setting time is within 10 hours; (2) when the dosage of desulfurization ash is 1 2%, the flexural strength is increased by 5 7% and the compressive strength is reduced by 1 2%. The results show that the formula two is better.

Characteristics and reactivity of rapidly hydrated sorbent for semidry flue gas desulfurization.

PubMed

Zhang, Jie; You, Changfu; Zhao, Suwei; Chen, Changhe; Qi, Haiying

2008-03-01

Semidry flue gas desulfurization with a rapidly hydrated sorbent was studied in a pilot-scale circulating fluidized bed (CFB) experimental facility. The desulfurization efficiency was measured for various operating parameters, including the sorbent recirculation rate and the water spray method. The experimental results show that the desulfurization efficiencies of the rapidly hydrated sorbent were 1.5-3.0 times higher than a commonly used industrial sorbent for calcium to sulfur molar ratios from 1.2 to 3.0, mainly due to the higher specific surface area and pore volume. The Ca(OH)2 content in the cyclone separator ash was about 2.9% for the rapidly hydrated sorbent and was about 0.1% for the commonly used industrial sorbent, due to the different adhesion between the fine Ca(OH)2 particles and the fly ash particles, and the low cyclone separation efficiency for the fine Ca(OH)2 particles that fell off the sorbent particles. Therefore the actual recirculation rates of the active sorbent with Ca(OH)2 particles were higher for the rapidly hydrated sorbent, which also contributed to the higher desulfurization efficiency. The high fly ash content in the rapidly hydrated sorbent resulted in good operating stability. The desulfurization efficiency with upstream water spray was 10-15% higher than that with downstream water spray.

Pressurized fluidized-bed hydroretorting of Eastern oil shales -- Sulfur control. Topical report for Subtask 3.1, In-bed sulfur capture tests; Subtask 3.2, Electrostatic desulfurization; Subtask 3.3, Microbial desulfurization and denitrification

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

Roberts, M.J.; Abbasian, J.; Akin, C.

1992-05-01

This topical report on ``Sulfur Control`` presents the results of work conducted by the Institute of Gas Technology (IGT), the Illinois Institute of Technology (IIT), and the Ohio State University (OSU) to develop three novel approaches for desulfurization that have shown good potential with coal and could be cost-effective for oil shales. These are (1) In-Bed Sulfur Capture using different sorbents (IGT), (2) Electrostatic Desulfurization (IIT), and (3) Microbial Desulfurization and Denitrification (OSU and IGT). The objective of the task on In-Bed Sulfur Capture was to determine the effectiveness of different sorbents (that is, limestone, calcined limestone, dolomite, and siderite)more » for capturing sulfur (as H{sub 2}S) in the reactor during hydroretorting. The objective of the task on Electrostatic Desulfurization was to determine the operating conditions necessary to achieve a high degree of sulfur removal and kerogen recovery in IIT`s electrostatic separator. The objectives of the task on Microbial Desulfurization and Denitrification were to (1) isolate microbial cultures and evaluate their ability to desulfurize and denitrify shale, (2) conduct laboratory-scale batch and continuous tests to improve and enhance microbial removal of these components, and (3) determine the effects of processing parameters, such as shale slurry concentration, solids settling characteristics, agitation rate, and pH on the process.« less

Analysis of Flue Gas Desulfurization (FGD) Processes for Potential Use on Army Coal-Fired Boilers

DTIC Science & Technology

1980-09-01

TECHNICAL REPORT N-93 September 1980 ANALYSIS OF FLUE GAS DESULFURIZATION (FGD) PROCESSES FOR POTENTIAL USE ON ARMY COAL-FIRED BOILERS TECHNICAL LIBRARY...REFERENCE: Technical Report N-93, Analysis of Flue Gas Desulfurization (FGD) Ppooesses for Potential Use on Army Coal-Fired Boilers Please take a few...REPORT DOCUMENTATION PAGE 1. REPORT NUMBER CERL-TR-N-93 2. GOVT ACCESSION NO «. TITLE (end Subtitle) ANALYSIS OF FLUE GAS DESULFURIZATION (FGD

Numerical Investigation of Desulfurization Kinetics in Gas-Stirred Ladles by a Quick Modeling Analysis Approach

NASA Astrophysics Data System (ADS)

Cao, Qing; Nastac, Laurentiu; Pitts-Baggett, April; Yu, Qiulin

2018-03-01

A quick modeling analysis approach for predicting the slag-steel reaction and desulfurization kinetics in argon gas-stirred ladles has been developed in this study. The model consists of two uncoupled components: (i) a computational fluid dynamics (CFD) model for predicting the fluid flow and the characteristics of slag-steel interface, and (ii) a multicomponent reaction kinetics model for calculating the desulfurization evolution. The steel-slag interfacial area and mass transfer coefficients predicted by the CFD simulation are used as the processing data for the reaction model. Since the desulfurization predictions are uncoupled from the CFD simulation, the computational time of this uncoupled predictive approach is decreased by at least 100 times for each case study when compared with the CFD-reaction kinetics fully coupled model. The uncoupled modeling approach was validated by comparing the evolution of steel and slag compositions with the experimentally measured data during ladle metallurgical furnace (LMF) processing at Nucor Steel Tuscaloosa, Inc. Then, the validated approach was applied to investigate the effects of the initial steel and slag compositions, as well as different types of additions during the refining process on the desulfurization efficiency. The results revealed that the sulfur distribution ratio and the desulfurization reaction can be promoted by making Al and CaO additions during the refining process. It was also shown that by increasing the initial Al content in liquid steel, both Al oxidation and desulfurization rates rapidly increase. In addition, it was found that the variation of the initial Si content in steel has no significant influence on the desulfurization rate. Lastly, if the initial CaO content in slag is increased or the initial Al2O3 content is decreased in the fluid-slag compositional range, the desulfurization rate can be improved significantly during the LMF process.

Numerical Investigation of Desulfurization Kinetics in Gas-Stirred Ladles by a Quick Modeling Analysis Approach

NASA Astrophysics Data System (ADS)

Cao, Qing; Nastac, Laurentiu; Pitts-Baggett, April; Yu, Qiulin

2018-06-01

A quick modeling analysis approach for predicting the slag-steel reaction and desulfurization kinetics in argon gas-stirred ladles has been developed in this study. The model consists of two uncoupled components: (i) a computational fluid dynamics (CFD) model for predicting the fluid flow and the characteristics of slag-steel interface, and (ii) a multicomponent reaction kinetics model for calculating the desulfurization evolution. The steel-slag interfacial area and mass transfer coefficients predicted by the CFD simulation are used as the processing data for the reaction model. Since the desulfurization predictions are uncoupled from the CFD simulation, the computational time of this uncoupled predictive approach is decreased by at least 100 times for each case study when compared with the CFD-reaction kinetics fully coupled model. The uncoupled modeling approach was validated by comparing the evolution of steel and slag compositions with the experimentally measured data during ladle metallurgical furnace (LMF) processing at Nucor Steel Tuscaloosa, Inc. Then, the validated approach was applied to investigate the effects of the initial steel and slag compositions, as well as different types of additions during the refining process on the desulfurization efficiency. The results revealed that the sulfur distribution ratio and the desulfurization reaction can be promoted by making Al and CaO additions during the refining process. It was also shown that by increasing the initial Al content in liquid steel, both Al oxidation and desulfurization rates rapidly increase. In addition, it was found that the variation of the initial Si content in steel has no significant influence on the desulfurization rate. Lastly, if the initial CaO content in slag is increased or the initial Al2O3 content is decreased in the fluid-slag compositional range, the desulfurization rate can be improved significantly during the LMF process.

Gas cleaning and hydrogen sulfide removal for COREX coal gas by sorption enhanced catalytic oxidation over recyclable activated carbon desulfurizer.

PubMed

Sun, Tonghua; Shen, Yafei; Jia, Jinping

2014-02-18

This paper proposes a novel self-developed JTS-01 desulfurizer and JZC-80 alkaline adsorbent for H2S removal and gas cleaning of the COREX coal gas in small-scale and commercial desulfurizing devices. JTS-01 desulfurizer was loaded with metal oxide (i.e., ferric oxides) catalysts on the surface of activated carbons (AC), and the catalyst capacity was improved dramatically by means of ultrasonically assisted impregnation. Consequently, the sulfur saturation capacity and sulfur capacity breakthrough increased by 30.3% and 27.9%, respectively. The whole desulfurizing process combined selective adsorption with catalytic oxidation. Moreover, JZC-80 adsorbent can effectively remove impurities such as HCl, HF, HCN, and ash in the COREX coal gas, stabilizing the system pressure drop. The JTS-01 desulfurizer and JZC-80 adsorbent have been successfully applied for the COREX coal gas cleaning in the commercial plant at Baosteel, Shanghai. The sulfur capacity of JTS-01 desulfurizer can reach more than 50% in industrial applications. Compared with the conventional dry desulfurization process, the modified AC desulfurizers have more merit, especially in terms of the JTS-01 desulfurizer with higher sulfur capacity and low pressure drop. Thus, this sorption enhanced catalytic desulfurization has promising prospects for H2S removal and other gas cleaning.

Peroxide-mediated desulfurization of phosphorothioate oligonucleotides and its prevention.

PubMed

Krotz, Achim H; Mehta, Rahul C; Hardee, Gregory E

2005-02-01

Desulfurization at the internucleotide phosphorothioate linkage of antisense oligonucleotides (ASOs) in dermatological formulations has been investigated using strong ion exchange chromatography and mass spectroscopy. The formation of phosphate diester linkages appeared to arise from a reaction between the phosphorothioate oligonucleotide and a potent oxidizing agent. Screening of excipients used in the formulation indicated that the cause of desulfurization was related to the presence of polyethylene glycol-derived nonionic surfactants MYRJ 52 or BRIJ 58. Autoxidation of the polyethylene glycol chain is suggested as the probable origin for the observed incompatibility. The ability of various antioxidants to prevent oxidative degradation of ASO-1 in simple test systems and in oil-in-water emulsions is described. It is found that in test systems both lipophilic and hydrophilic antioxidants are effective. However, in cream formulation (oil-in-water emulsions) of ASO-1 the addition of hydrophilic antioxidants L-cysteine or DL-alpha-lipoic acid has been shown to be superior in protecting the oligonucleotide from desulfurization upon storage. Copyright 2004 Wiley-Liss, Inc.

Coal desulfurization by chlorinolysis production and combustion test evaluation of product coals

NASA Technical Reports Server (NTRS)

Kalvinskas, J. J.; Daly, D.

1982-01-01

Laboratory-scale screening tests were carried out on coal from Harrison County, Ohio to establish chlorination and hydrodesulfurization conditions for the batch reactor production of chlorinolysis and chlorinolysis-hydrodesulfurized coals. In addition, three bituminous coals, were treated on the lab scale by the chlorinolysis process to provide 39 to 62% desulfurization. Two bituminous coals and one subbituminous coal were then produced in 11 to 15 pound lots as chlorinolysis and hydrodesulfurized coals. The chlorinolysis coals had a desulfurization of 29-69%, reductions in voltatiles and hydrogen. Hydrodesulfurization provided a much greater desulfurization (56-86%), reductions in volatiles and hydrogen. The three coals were combustion tested in the Penn State ""plane flame furnace'' to determine ignition and burning characteristics. All three coals burned well to completion as: raw coals, chlorinolysis processed coals, and hydrodesulfurized coals. The hydrodesulfurized coals experienced greater ignition delays and reduced burning rates than the other coals because of the reduced volatile content. It is thought that the increased open pore volume in the desulfurized-devolatilized coals compensates in part for the decreased volatiles effect on ignition and burning.

Coal Liquefaction desulfurization process

DOEpatents

Givens, Edwin N.

1983-01-01

In a solvent refined coal liquefaction process, more effective desulfurization of the high boiling point components is effected by first stripping the solvent-coal reacted slurry of lower boiling point components, particularly including hydrogen sulfide and low molecular weight sulfur compounds, and then reacting the slurry with a solid sulfur getter material, such as iron. The sulfur getter compound, with reacted sulfur included, is then removed with other solids in the slurry.

Biocatalytic Conversion of Avermectin to 4"-Oxo-Avermectin: Heterologous Expression of the ema1 Cytochrome P450 Monooxygenase

PubMed Central

Molnár, István; Hill, D. Steven; Zirkle, Ross; Hammer, Philip E.; Gross, Frank; Buckel, Thomas G.; Jungmann, Volker; Pachlatko, Johannes Paul; Ligon, James M.

2005-01-01

The cytochrome P450 monooxygenase Ema1 from Streptomyces tubercidicus R-922 and its homologs from closely related Streptomyces strains are able to catalyze the regioselective oxidation of avermectin into 4"-oxo-avermectin, a key intermediate in the manufacture of the agriculturally important insecticide emamectin benzoate (V. Jungmann, I. Molnár, P. E. Hammer, D. S. Hill, R. Zirkle, T. G. Buckel, D. Buckel, J. M. Ligon, and J. P. Pachlatko, Appl. Environ. Microbiol. 71:6968-6976, 2005). The gene for Ema1 has been expressed in Streptomyces lividans, Streptomyces avermitilis, and solvent-tolerant Pseudomonas putida strains using different promoters and vectors to provide biocatalytically competent cells. Replacing the extremely rare TTA codon with the more frequent CTG codon to encode Leu4 in Ema1 increased the biocatalytic activities of S. lividans strains producing this enzyme. Ferredoxins and ferredoxin reductases were also cloned from Streptomyces coelicolor and biocatalytic Streptomyces strains and tested in ema1 coexpression systems to optimize the electron transport towards Ema1. PMID:16269733

Use of a Ceramic Membrane to Improve the Performance of Two-Separate-Phase Biocatalytic Membrane Reactor.

PubMed

Ranieri, Giuseppe; Mazzei, Rosalinda; Wu, Zhentao; Li, Kang; Giorno, Lidietta

2016-03-14

Biocatalytic membrane reactors (BMR) combining reaction and separation within the same unit have many advantages over conventional reactor designs. Ceramic membranes are an attractive alternative to polymeric membranes in membrane biotechnology due to their high chemical, thermal and mechanical resistance. Another important use is their potential application in a biphasic membrane system, where support solvent resistance is highly needed. In this work, the preparation of asymmetric ceramic hollow fibre membranes and their use in a two-separate-phase biocatalytic membrane reactor will be described. The asymmetric ceramic hollow fibre membranes were prepared using a combined phase inversion and sintering technique. The prepared fibres were then used as support for lipase covalent immobilization in order to develop a two-separate-phase biocatalytic membrane reactor. A functionalization method was proposed in order to increase the density of the reactive hydroxyl groups on the surface of ceramic membranes, which were then amino-activated and treated with a crosslinker. The performance and the stability of the immobilized lipase were investigated as a function of the amount of the immobilized biocatalytst. Results showed that it is possible to immobilize lipase on a ceramic membrane without altering its catalytic performance (initial residual specific activity 93%), which remains constant after 6 reaction cycles.

Sequential lignin depolymerization by combination of biocatalytic and formic acid/formate treatment steps.

PubMed

Gasser, Christoph A; Čvančarová, Monika; Ammann, Erik M; Schäffer, Andreas; Shahgaldian, Patrick; Corvini, Philippe F-X

2017-03-01

Lignin, a complex three-dimensional amorphous polymer, is considered to be a potential natural renewable resource for the production of low-molecular-weight aromatic compounds. In the present study, a novel sequential lignin treatment method consisting of a biocatalytic oxidation step followed by a formic acid-induced lignin depolymerization step was developed and optimized using response surface methodology. The biocatalytic step employed a laccase mediator system using the redox mediator 1-hydroxybenzotriazole. Laccases were immobilized on superparamagnetic nanoparticles using a sorption-assisted surface conjugation method allowing easy separation and reuse of the biocatalysts after treatment. Under optimized conditions, as much as 45 wt% of lignin could be solubilized either in aqueous solution after the first treatment or in ethyl acetate after the second (chemical) treatment. The solubilized products were found to be mainly low-molecular-weight aromatic monomers and oligomers. The process might be used for the production of low-molecular-weight soluble aromatic products that can be purified and/or upgraded applying further downstream processes.

Desulfurization of dibenzothiophene (DBT) by a novel strain Lysinibacillus sphaericus DMT-7 isolated from diesel contaminated soil.

PubMed

Bahuguna, Ashutosh; Lily, Madhuri K; Munjal, Ashok; Singh, Ravindra N; Dangwal, Koushalya

2011-01-01

A new bacterial strain DMT-7 capable of selectively desulfurizing dibenzothiophene (DBT) was isolated from diesel contaminated soil. The DMT-7 was characterized and identified as Lysinibacillus sphaericus DMT-7 (NCBI GenBank Accession No. GQ496620) using 16S rDNA gene sequence analysis. The desulfurized product of DBT, 2-hydroxybiphenyl (2HBP), was identified and confirmed by high performance liquid chromatography analysis and gas chromatography-mass spectroscopy analysis respectively. The desulfurization kinetics revealed that DMT-7 started desulfurization of DBT into 2HBP after the lag phase of 24 hr, exponentially increasing the accumulation of 2HBP up to 15 days leading to approximately 60% desulfurization of the DBT. However, further growth resulted into DBT degradation. The induced culture of DMT-7 showed shorter lag phase of 6 hr and early onset of stationary phase within 10 days for desulfurization as compared to that of non-induced culture clearly indicating the inducibility of the desulfurization pathway of DMT-7. In addition, Lysinibacillus sphaericus DMT-7 also possess the ability to utilize broad range of substrates as sole source of sulfur such as benzothiophene, 3,4-benzo DBT, 4,6-dimethyl DBT, and 4,6-dibutyl DBT. Therefore, Lysinibacillus sphaericus DMT-7 could serve as model system for efficient biodesulfurization of diesel and petrol.

Recombinant DNA encoding a desulfurization biocatalyst

DOEpatents

Rambosek, John; Piddington, Chris S.; Kovacevich, Brian R.; Young, Kevin D.; Denome, Sylvia A.

1994-01-01

This invention relates to a recombinant DNA molecule containing a gene or genes which encode a biocatalyst capable of desulfurizing a fossil fuel which contains organic sulfur molecules. For example, the present invention encompasses a recombinant DNA molecule containing a gene or genes of a strain of Rhodococcus rhodochrous.

Superoxide radical and UV irradiation in ultrasound assisted oxidative desulfurization (UAOD): A potential alternative for greener fuels

NASA Astrophysics Data System (ADS)

Chan, Ngo Yeung

This study is aimed at improving the current ultrasound assisted oxidative desulfurization (UAOD) process by utilizing superoxide radical as oxidant. Research was also conducted to investigate the feasibility of ultraviolet (UV) irradiation-assisted desulfurization. These modifications can enhance the process with the following achievements: (1) Meet the upcoming sulfur standards on various fuels including diesel fuel oils and residual oils; (2) More efficient oxidant with significantly lower consumption in accordance with stoichiometry; (3) Energy saving by 90%; (4) Greater selectivity in petroleum composition. Currently, the UAOD process and subsequent modifications developed in University of Southern California by Professor Yen's research group have demonstrated high desulfurization efficiencies towards various fuels with the application of 30% wt. hydrogen peroxide as oxidant. The UAOD process has demonstrated more than 50% desulfurization of refractory organic sulfur compounds with the use of Venturella type catalysts. Application of quaternary ammonium fluoride as phase transfer catalyst has significantly improved the desulfurization efficiency to 95%. Recent modifications incorporating ionic liquids have shown that the modified UAOD process can produce ultra-low sulfur, or near-zero sulfur diesels under mild conditions with 70°C and atmospheric pressure. Nevertheless, the UAOD process is considered not to be particularly efficient with respect to oxidant and energy consumption. Batch studies have demonstrated that the UAOD process requires 100 fold more oxidant than the stoichiometic requirement to achieve high desulfurization yield. The expected high costs of purchasing, shipping and storage of the oxidant would reduce the practicability of the process. The excess use of oxidant is not economically desirable, and it also causes environmental and safety issues. Post treatments would be necessary to stabilize the unspent oxidant residual to prevent the waste

Effect of Silicon on the Desulfurization of Al-Killed Steels: Part II. Experimental Results and Plant Trials

NASA Astrophysics Data System (ADS)

Roy, Debdutta; Pistorius, Petrus Christiaan; Fruehan, Richard J.

2013-10-01

Recent observations suggest that increased silicon levels improve ladle desulfurization of aluminum-killed steel. A kinetic model was developed and presented in part I of this paper, demonstrating that increased silicon levels in steel suppress the consumption of aluminum by parasitic reactions like silica reduction and FeO/MnO reduction, thus making more aluminum available at the interface for desulfurization. The results are increases in the rate and the extent of desulfurization. Predictions were compared with laboratory induction furnace melts using 1 kg of steel and 0.1 kg slag. The experimental results demonstrate the beneficial effect of silicon on the desulfurization reaction and that alumina can be reduced out of the slag and aluminum picked up by the steel, if the silicon content in the steel is high enough. The experimental results are in close agreement with the model predictions. Plant trials also show that with increased silicon content, both the rate and extent of desulfurization increase; incorporating silicon early into the ladle desulfurization process leads to considerable savings in aluminum consumption.

Biocatalytic Conversion of Avermectin to 4″-Oxo-Avermectin: Improvement of Cytochrome P450 Monooxygenase Specificity by Directed Evolution▿ †

PubMed Central

Trefzer, Axel; Jungmann, Volker; Molnár, István; Botejue, Ajit; Buckel, Dagmar; Frey, Gerhard; Hill, D. Steven; Jörg, Mario; Ligon, James M.; Mason, Dylan; Moore, David; Pachlatko, J. Paul; Richardson, Toby H.; Spangenberg, Petra; Wall, Mark A.; Zirkle, Ross; Stege, Justin T.

2007-01-01

Discovery of the CYP107Z subfamily of cytochrome P450 oxidases (CYPs) led to an alternative biocatalytic synthesis of 4″-oxo-avermectin, a key intermediate for the commercial production of the semisynthetic insecticide emamectin. However, under industrial process conditions, these wild-type CYPs showed lower yields due to side product formation. Molecular evolution employing GeneReassembly was used to improve the regiospecificity of these enzymes by a combination of random mutagenesis, protein structure-guided site-directed mutagenesis, and recombination of multiple natural and synthetic CYP107Z gene fragments. To assess the specificity of CYP mutants, a miniaturized, whole-cell biocatalytic reaction system that allowed high-throughput screening of large numbers of variants was developed. In an iterative process consisting of four successive rounds of GeneReassembly evolution, enzyme variants with significantly improved specificity for the production of 4″-oxo-avermectin were identified; these variants could be employed for a more economical industrial biocatalytic process to manufacture emamectin. PMID:17483257

Recombinant DNA encoding a desulfurization biocatalyst

DOEpatents

Rambosek, J.; Piddington, C.S.; Kovacevich, B.R.; Young, K.D.; Denome, S.A.

1994-10-18

This invention relates to a recombinant DNA molecule containing a gene or genes which encode a biocatalyst capable of desulfurizing a fossil fuel which contains organic sulfur molecules. For example, the present invention encompasses a recombinant DNA molecule containing a gene or genes of a strain of Rhodococcus rhodochrous. 13 figs.

Synthesis and application of different phthalocyanine molecular sieve catalyst for oxidative desulfurization

NASA Astrophysics Data System (ADS)

Zhao, Na; Li, Siwen; Wang, Jinyi; Zhang, Ronglan; Gao, Ruimin; Zhao, Jianshe; Wang, Junlong

2015-05-01

M2(PcAN)2 (M=Fe, Co, Ni, Cu, Zn and Mn) anchored onto W-HZSM-5 (M2(PcAN)2-W-HZSM-5) or the M2(PcTN)2 doping W-HZSM-5 (M2(PcTN)2/W-HZSM-5) were prepared and their catalytic performances were tested for oxidative desulfurization in the presence of oxygen. Thiophene (T), benzothiophene (BT), and dibenzothiophene (DBT) were considered as sulfur compounds. Among zeolite-based catalysts, the Cu2(PcAN)2-W-HZSM-5 and Cu2(PcTN)2/W-HZSM-5 showed superior desulfurization performance and the activity of selectivity followed the order: T>BT>DBT. The effects of phthalocyanine concentration were studied by UV-Vis and calcination temperature was obtained by TG-DSC for Cu2(PcTN)2/W-HZSM-5. Catalysts were characterized by EA, IR, XRD, SEM, TEM, ICP, and N2 adsorption. Reaction time, temperature and the amount of catalyst were investigated as the important parameters for optimization of the reaction. Furthermore, a possible process of oxidative desulfurization and the reaction products were proposed. The reaction process of ultra-deep desulfurization.

Exploring the Mechanism of Biocatalyst Inhibition in Microbial Desulfurization

PubMed Central

Abin-Fuentes, Andres; Mohamed, Magdy El-Said; Wang, Daniel I. C.

2013-01-01

Microbial desulfurization, or biodesulfurization (BDS), of fuels is a promising technology because it can desulfurize compounds that are recalcitrant to the current standard technology in the oil industry. One of the obstacles to the commercialization of BDS is the reduction in biocatalyst activity concomitant with the accumulation of the end product, 2-hydroxybiphenyl (HBP), during the process. BDS experiments were performed by incubating Rhodococcus erythropolis IGTS8 resting-cell suspensions with hexadecane at 0.50 (vol/vol) containing 10 mM dibenzothiophene. The resin Dowex Optipore SD-2 was added to the BDS experiments at resin concentrations of 0, 10, or 50 g resin/liter total volume. The HBP concentration within the cytoplasm was estimated to decrease from 1,100 to 260 μM with increasing resin concentration. Despite this finding, productivity did not increase with the resin concentration. This led us to focus on the susceptibility of the desulfurization enzymes toward HBP. Dose-response experiments were performed to identify major inhibitory interactions in the most common BDS pathway, the 4S pathway. HBP was responsible for three of the four major inhibitory interactions identified. The concentrations of HBP that led to a 50% reduction in the enzymes' activities (IC50s) for DszA, DszB, and DszC were measured to be 60 ± 5 μM, 110 ± 10 μM, and 50 ± 5 μM, respectively. The fact that the IC50s for HBP are all significantly lower than the cytoplasmic HBP concentration suggests that the inhibition of the desulfurization enzymes by HBP is responsible for the observed reduction in biocatalyst activity concomitant with HBP generation. PMID:24096431

Ultrasound-assisted oxidative desulfurization of bunker-C oil using tert-butyl hydroperoxide.

PubMed

Tang, Qiong; Lin, Song; Cheng, Ying; Liu, Sujun; Xiong, Jun-Ru

2013-09-01

This work investigated the ultrasonic assisted oxidative desulfurization of bunker-C oil with TBHP/MoO3 system. The operational parameters for the desulfurization procedure such as ultrasonic irradiation time, ultrasonic wave amplitude, catalyst initial concentration and oxidation agent initial concentration were studied. The experimental results show that the present oxidation system was very efficient for the desulfurization of bunker-C oil and ~35% sulfur was removed which was dependent on operational parameters. The application of ultrasonic irradiation allowed sulfur removal in a shorter time. The stronger the solvent polarity is, the higher the sulfur removal rate, but the recovery rate of oil is lower. The sulfur compounds in bunker-C oil reacted with TBHP to produce corresponding sulfoxide, and further oxidation produced the corresponding sulfone. Copyright © 2013 Elsevier B.V. All rights reserved.

Optimizing the biocatalytic productivity of an engineered sialidase from Trypanosoma rangeli for 3'-sialyllactose production.

PubMed

Zeuner, Birgitte; Luo, Jianquan; Nyffenegger, Christian; Aumala, Ville; Mikkelsen, Jørn Dalgaard; Meyer, Anne S

2014-02-05

An engineered sialidase, Tr6, from Trypanosoma rangeli was used for biosynthetic production of 3'-sialyllactose, a human milk oligosaccharide case compound, from casein glycomacropeptide (CGMP) and lactose, components abundantly present in industrial dairy side streams. Four different enzyme re-use methods were compared to optimize the biocatalytic productivity, i.e. 3'-sialyllactose formation per amount of Tr6 employed: (i) His-tag immobilization on magnetic Cu²⁺-iminodiacetic acid-functionalized nanoparticles (MNPs), (ii) membrane immobilization, (iii) calcium alginate encapsulation of cross-linked Tr6, and (iv) Tr6 catalysis in a membrane reactor. Tr6 immobilized on MNPs gave a biocatalytic productivity of 84 mg 3'-sialyllactose/mg Tr6 after seven consecutive reaction runs. Calcium-alginate and membrane immobilization were inefficient. Using free Tr6 in a 10 kDa membrane reactor produced a 9-fold biocatalytic productivity increase compared to using free Tr6 in a batch reactor giving 306 mg 3'-sialyllactose/mg Tr6 after seven consecutive reaction runs. The 3'-sialyllactose yield on α-2,3-bound sialic acid in CGMP was 74%. Using circular dichroism, a temperature denaturation midpoint of Tr6, Tm, of 57.2 °C was determined. The thermal stability of free Tr6 was similarly high and the Tr6 was stable at the reaction temperature (25 °C) for at least 24 h. Copyright © 2013 Elsevier Inc. All rights reserved.

Unraveling heavy oil desulfurization chemistry: targeting clean fuels.

PubMed

Choudhary, Tushar V; Parrott, Stephen; Johnson, Byron

2008-03-15

The sulfur removal chemistry of heavy oils has been unraveled by systematically investigating several heavy oils with an extremely wide range of properties. The heavy oil feed and product properties have been characterized by advanced analytical methods, and these properties have been related to the sulfur conversion data observed in pilot hydrotreating units. These studies coupled with kinetic treatment of the data have revealed that the desulfurization chemistry of heavy oils is essentially controlled by the strongly inhibiting three and larger ring aromatic hydrocarbon content and surprisingly not by the content of the "hard-to-remove" sulfur compounds. Such enhanced understanding of the heavy oil sulfur removal is expected to open new avenues for catalyst/process optimization for heavy oil desulfurization and thereby assist the efficent production of clean transporation fuels.

Use of Flue Gas Desulfurization (FGD) Gypsum as a Heavy Metal Stabilizer in Contaminated Soils

EPA Science Inventory

Flue Gas Desulfurization (FGD) gypsum is a synthetic by-product generated from the flue gas desulfurization process in coal power plants. It has several beneficial applications such as an ingredient in cement production, wallboard production and in agricultural practice as a soil...

Method for enhancing the desulfurization of hot coal gas in a fluid-bed coal gasifier

DOEpatents

Grindley, Thomas

1989-01-01

A process and apparatus for providing additional desulfurization of the hot gas produced in a fluid-bed coal gasifier, within the gasifier. A fluid-bed of iron oxide is located inside the gasifier above the gasification bed in a fluid-bed coal gasifier in which in-bed desulfurization by lime/limestone takes place. The product gases leave the gasification bed typically at 1600.degree. to 1800.degree. F. and are partially quenched with water to 1000.degree. to 1200.degree. F. before entering the iron oxide bed. The iron oxide bed provides additional desulfurization beyond that provided by the lime/limestone.

Efficiency Analysis and Mechanism Insight of that Whole-Cell Biocatalytic Production of Melibiose from Raffinose with Saccharomyces cerevisiae.

PubMed

Zhou, Yingbiao; Zhu, Yueming; Dai, Longhai; Men, Yan; Wu, Jinhai; Zhang, Juankun; Sun, Yuanxia

2017-01-01

Melibiose is widely used as a functional carbohydrate. Whole-cell biocatalytic production of melibiose from raffinose could reduce its cost. However, characteristics of strains for whole-cell biocatalysis and mechanism of such process are unclear. We compared three different Saccharomyces cerevisiae strains (liquor, wine, and baker's yeasts) in terms of concentration variations of substrate (raffinose), target product (melibiose), and by-products (fructose and galactose) in whole-cell biocatalysis process. Distinct difference was observed in whole-cell catalytic efficiency among three strains. Furthermore, activities of key enzymes (invertase, α-galactosidase, and fructose transporter) involved in process and expression levels of their coding genes (suc2, mel1, and fsy1) were investigated. Conservation of key genes in S. cerevisiae strains was also evaluated. Results show that whole-cell catalytic efficiency of S. cerevisiae in the raffinose substrate was closely related to activity of key enzymes and expression of their coding genes. Finally, we summarized characteristics of producing strain that offered advantages, as well as contributions of key genes to excellent strains. Furthermore, we presented a dynamic mechanism model to achieve some mechanism insight for this whole-cell biocatalytic process. This pioneering study should contribute to improvement of whole-cell biocatalytic production of melibiose from raffinose.

Simple biogas desulfurization by microaeration - Full scale experience.

PubMed

Jeníček, P; Horejš, J; Pokorná-Krayzelová, L; Bindzar, J; Bartáček, J

2017-08-01

Hydrogen sulfide in biogas is common problem during anaerobic treatment of wastewater with high sulfate concentration (breweries, distilleries, etc.) and needs to be removed before biogas utilization. Physico-chemical desulfurization methods are energetically demanding and expensive compare to biochemical methods. Microaeration, i.e. dosing of small amount of air, is suitable and cost effective biochemical method of sulfide oxidation to elemental sulfur. It has been widely used in biogas plants, but its application in anaerobic reactors for wastewater treatment has been rarely studied or tested. The lack of full-scale experience with microaeration in wastewater treatment plants has been overcome by evaluating the results of seven microaerobic digesters in central Europe. The desulfurization efficiency has been more than 90% in most of the cases. Moreover, microaeration improved the degradability of COD and volatile suspended solids. Copyright © 2017 Elsevier Ltd. All rights reserved.

Production of uridine 5'-monophosphate by Corynebacterium ammoniagenes ATCC 6872 using a statistically improved biocatalytic process.

PubMed

Wang, Xing; Wang, Xiuwen; Yin, Mengxin; Xiao, Zijun; Ma, Cuiqing; Lin, Zhixin; Wang, Peng George; Xu, Ping

2007-08-01

Attempts were made with success to develop a two-step biocatalytic process for uridine 5'-monophosphate (UMP) production from orotic acid by Corynebacterium ammoniagenes ATCC 6872: the strain was first cultivated in a high salt mineral medium, and then cells were harvested and used as the catalyst in the UMP production reaction. Effects of cultivation and reaction conditions on UMP production were investigated. The cells exhibited the highest biocatalytic ability when cultivated in a medium containing corn steep liquor at pH 7.0 for 15 h in the exponential phase of growth. To optimize the reaction, both "one-factor-at-a-time" method and statistical method were performed. By "one-factor-at-a-time" optimization, orotic acid, glucose, phosphate ion (equimolar KH(2)PO(4) and K(2)HPO(4)), MgCl(2), Triton X-100 were shown to be the optimum components for the biocatalytic reaction. Phosphate ion and C. ammoniagenes cell were furthermore demonstrated as the most important main effects on UMP production by Plackett-Burman design, indicating that 5-phosphoribosyl-1-pyrophosphate (PRPP) synthesis was the rate-limiting step for pyrimidine nucleotides production. Optimization by a central composition design (CCD) was then performed, and up to 32 mM (10.4 g l(-1)) UMP was accumulated in 24 h from 38.5 mM (6 g l(-1)) orotic acid. The yield was threefold higher than the original UMP yield before optimization.

Removal of Sulfur from CaF2 Containing Desulfurization Slag Exhausted from Secondary Steelmaking Process by Oxidation

NASA Astrophysics Data System (ADS)

Hiraki, Takehito; Kobayashi, Junichi; Urushibata, Satomi; Matsubae, Kazuyo; Nagasaka, Tetsuya

2012-08-01

The oxidation behavior of sulfur in desulfurization slag generated from the secondary steelmaking process with air has been investigated in the temperature range of 973 K to 1373 K (700 °C to 1100 °C). Although a high removal rate of sulfur is not achieved at temperatures lower than 1273 K (1000 °C) because of the formation of CaSO4, most of the sulfur is rapidly removed from slag as SO2 gas in the 1273 K to 1373 K (700 °C to 1100 °C) range. This finding indicates that the desulfurization slag generated from the secondary steelmaking process can be reused as a desulfurized flux through air oxidation, making it possible to reduce significantly the amount of desulfurization slag for disposal.

Coal desulfurization by aqueous chlorination

NASA Technical Reports Server (NTRS)

Kalvinskas, J. J.; Vasilakos, N.; Corcoran, W. H.; Grohmann, K.; Rohatgi, N. K. (Inventor)

1982-01-01

A method of desulfurizing coal is described in which chlorine gas is bubbled through an aqueous slurry of coal at low temperature below 130 degrees C., and at ambient pressure. Chlorinolysis converts both inorganic and organic sulfur components of coal into water soluble compounds which enter the aqueous suspending media. The media is separated after chlorinolysis and the coal dechlorinated at a temperature of from 300 C to 500 C to form a non-caking, low-sulfur coal product.

Deep catalytic oxidative desulfurization (ODS) of dibenzothiophene (DBT) with oxalate-based deep eutectic solvents (DESs).

PubMed

Lü, Hongying; Li, Pengcheng; Deng, Changliang; Ren, Wanzhong; Wang, Shunan; Liu, Pan; Zhang, Han

2015-07-07

An oxalate-based DES with a tetrabutyl ammonium chloride and oxalate acid molar ratio of 1/2 (TBO1 : 2) exhibited high activity in oxidative desulfurization (ODS) of dibenzothiophene (DBT) under mild reaction conditions. It is potentially a promising and highly environmentally friendly approach for desulfurization of fuels.

Experimental Study on Hot Metal Desulfurization Using Sintered Red Mud-Based Flux

NASA Astrophysics Data System (ADS)

Li, Fengshan; Zhang, Yanling; Guo, Zhancheng

2017-09-01

This research presents the results of laboratory and pilot-scale tests conducted on the use of sintered red mud (RM)-based flux in the hot metal desulfurization (HMD) process. Al2O3/Na2O in RM can decrease the melting point of lime-based slag and can work as a flux in the HMD process. Good slag fluidity was observed throughout the process, and high desulfurization rates ( 80%) with a low final S content (<0.02%) were experimentally obtained when the RM:CaO ratio was between 1.2:1 and 2.4:1. The pilot-scale test results indicated that a desulfurization rate as high as 91% and a S content <0.0099% could be acquired when RM:lime = 1:1, verifying the feasibility of using sintered RM-based flux in HMD. The data obtained provide important information for promoting the large-scale application of sintered RM in steelmaking.

FLUE GAS DESULFURIZATION: THE STATE OF THE ART

EPA Science Inventory

The paper gives results of a review of commercially available flue gas desulfurization (FGD) technologies that have an established record of full-scale performance. (NOTE: Sulfur dioxide (SO2) scrubbers may be used by coal-fired electrcity generating units to meet the requiremen...

Enhancement of Oxidative Desulfurization Performance over UiO-66(Zr) by Titanium Ion Exchange.

PubMed

Ye, Gan; Qi, Hui; Li, Xiaolin; Leng, Kunyue; Sun, Yinyong; Xu, Wei

2017-07-19

Oxidative desulfurization is considered to be one of the most promising methods for producing ultra-low-sulfur fuels because it can effectively remove refractory sulfur-containing aromatic compounds under mild conditions. In this work, the oxidative desulfurization performance over UiO-66(Zr) is greatly enhanced by Ti ion exchange. This strategy is not only efficient for UiO-66(Zr) with crystal defects but also for UiO-66(Zr) with high crystallinity. In particular, the performance of UiO-66(Zr) with high crystallinity in the oxidative desulfurization of dibenzothiophene can be improved more than 11-fold, which can be mainly attributed to the introduction of active Ti sites. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sulfur-selective desulfurization of dibenzothiophene and diesel oil by newly isolated Rhodococcus sp. strains.

PubMed

Castorena, Gladys; Suárez, Claudia; Valdez, Idania; Amador, Guadalupe; Fernández, Luis; Le Borgne, Sylvie

2002-09-24

New desulfurizing bacteria able to convert dibenzothiophene into 2-hydroxybiphenyl and sulfate were isolated from contaminated soils collected in Mexican refineries. Random amplified polymorphic DNA analysis showed they were different from previously reported Rhodococcus erythropolis desulfurizing strains. According to 16S rRNA gene sequencing and fatty acid analyses, these new isolates belonged to the genus Rhodococcus. These strains could desulfurize 4,6-dimethyldibenzothiophene which is one of the most difficult dibenzothiophene derivatives to remove by hydrodesulfurization. A deeply hydrodesulfurized diesel oil containing significant amounts of 4,6-dimethyldibenzothiophene was treated with Rhodococcus sp. IMP-S02 cells. Up to 60% of the total sulfur was removed and all the 4,6-dimethyldibenzothiophene disappeared as a result of this treatment.

Desulfurization by MOFs as Sorbents for Thiophene Sulfides

NASA Astrophysics Data System (ADS)

Xin, Chunling; Wang, Suqing

2018-01-01

Metal-organic frameworks UMCM-150 [Cu3(BHTC)2] and its heterobimetallic analogue Co1Cu2(BHTC)2 based on an asymmetrical ligand, biphenyl-3,4’,5-tricarboxylate (H3BHTC), were studied for desulfurization of model oils. The adsorption experiments were conducted under room temperature and atmospheric pressure. The total sulfur concentration of model oils was 250 ppmw determined by WK-2D coulomb integrated micro-analyzer through adding benzothiophene (BT) and dibenzothiophene (DBT) into liquid alkanes. Adsorptive desulfurization experiments were conducted in a consecutive fixed bed adsorption system. The results indicate that Cu3(BHTC)2 has a higher sulfur-capacity than Co1Cu2(BHTC)2. Taking DBT as an example, Cu3(BHTC)2 and Co1Cu2(BHTC)2 have breakthrough adsorption capacities of 10.6 and 5.8 g S/kg of sorbent for model oils.

Experimental research on bypass evaporation tower technology for zero liquid discharge of desulfurization wastewater.

PubMed

Ma, Shuangchen; Chai, Jin; Wu, Kai; Xiang, Yajun; Jia, Shaoguang; Li, Qingsong

2018-03-20

Zero liquid discharge (ZLD) of wastewater has become the trend of environmental governance after the implementation of 'The Action Plan for Prevention and Treatment of Water Pollution' in China, desulfurization wastewater has gained more attention due to its complex composition and heavy metals. However, current technologies for ZLD have some shortcomings such as high cost and insufficient processing capacity, ZLD cannot be achieved actually. This paper proposes a new evaporation drying technology. An independent bypass evaporation tower was built, part of the hot flue gas before the air preheater was introduced into the evaporation tower for desulfurization wastewater evaporation, and the generated dust after evaporation was discharged back to the flue duct before electrostatic precipitator. This paper reports on the performance of desulfurization wastewater evaporation and the characteristics of evaporation products in depth and makes a comprehensive discussion of the impact on the existing equipment based on the self-designed evaporation tower. Research suggests that this technology has high system reliability and little effect on subsequent equipment and provides theoretical and practical data. Due to environmental policies and huge market demand for ZLD of desulfurization wastewater, bypass evaporation tower technology has a great application prospect in the future.

MARKETING OF BYPRODUCT GYPSUM FROM FLUE GAS DESULFURIZATION

EPA Science Inventory

The report gives results of an evaluation of the 1985 marketing potential of byproduct gypsum from utility flue gas desulfurization (FGD), for the area east of the Rocky Mountains, using the calculated gypsum production rates of 14 selected power plants. The 114 cement plants and...

Deep desulfurization by amphiphilic lanthanide-containing polyoxometalates in ionic-liquid emulsion systems under mild conditions.

PubMed

Xu, Junhua; Zhao, Shen; Ji, Yuanchun; Song, Yu-Fei

2013-01-07

Amphiphilic lanthanide-containing polyoxometalates (POMs) were prepared by surfactant encapsulation. Investigation of these lanthanide-containing POMs in oxidative desulfurization (ODS) showed that highly efficient deep desulfurization could be achieved in only 14 min with 100% conversion of dibenzothiophene under mild conditions by using (DDA)(9)LaW(10)/[omim]PF(6) (DDA=dimethyldioctadecylammonium, omim=1-octyl-3-methyl-imidazolium) in the presence of H(2) O(2) . Furthermore, deep desulfurization proceeds smoothly in model oil with an S content as low as 50 ppm. A scaled-up experiment in which the volume of model oil was increased from 5 to 1000 mL with S content of 1000 ppm indicated that about 99% sulfur removal can be achieved in 40 mins in an ionic-liquid emulsion system. To the best of our knowledge, the (DDA)(9)LaW(10)/[omim]PF(6) catalyst system with H(2)O(2) as oxidant is one of the most efficient desulfurization systems reported so far. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

a Numerical Model for Flue Gas Desulfurization System.

NASA Astrophysics Data System (ADS)

Kim, Sung Joon

The purpose of this work is to develop a reliable numerical model for spray dryer desulfurization systems. The shape of the spray dryer requires that a body fitted orthogonal coordinate system be used for the numerical model. The governing equations are developed in the general orthogonal coordinates and discretized to yield a system of algebraic equations. A turbulence model is also included in the numerical program. A new second order numerical scheme is developed and included in the numerical model. The trajectory approach is used to simulate the flow of the dispersed phase. Two-way coupling phenomena is modeled by this scheme. The absorption of sulfur dioxide into lime slurry droplets is simulated by a model based on gas -phase mass transfer. The program is applied to a typical spray dryer desulfurization system. The results show the capability of the program to predict the sensitivity of system performance to changes in operational parameters.

Improving the desulfurization performance of CaCO3 with sodium humate

NASA Astrophysics Data System (ADS)

Feng, Run; Sun, Zhiguo; Zhang, Wenqing; Huang, Hao; Hu, Haihang; Zhang, Li; Xie, Hongyong

2018-02-01

The influence of these factors on desulphurization efficiency was studied by changing the amount of calcium carbonate, the concentration of sulfur dioxide, the liquid flow rate of absorbent and the air flow rate, the optimum working condition was determined by the research of limestone-gypsum desulphurization process commonly used in industry. By changing the amount of calcium carbonate, we conclude that the volume of water in the desulfurization efficiency does not increase with the adding amount of calcium carbonate. The optimum conditions were determined : at the condicion of the concentration of 500ppm of sulfur dioxide, 10g calcium carbonate, 150L/h liquid flow and the minimum air flow rate of 6.75m3/h, the highest desulfurization efficiency was close to 100% when sodium humate was not added, but the holding time was only about 5 minutes. After adding 3g of humic acid, the desulfurization efficiency was improved obviously, and the instantaneous efficiency of 100% lasting for about 40 minutes. It can be seen that, calcium carbonate in the addition of humic acid sodium can significantly improve the absorption of calcium carbonate performance of SO2.

Sequence and molecular characterization of a DNA region encoding the dibenzothiophene desulfurization operon of Rhodococcus sp. strain IGTS8.

PubMed Central

Piddington, C S; Kovacevich, B R; Rambosek, J

1995-01-01

Dibenzothiophene (DBT), a model compound for sulfur-containing organic molecules found in fossil fuels, can be desulfurized to 2-hydroxybiphenyl (2-HBP) by Rhodococcus sp. strain IGTS8. Complementation of a desulfurization (dsz) mutant provided the genes from Rhodococcus sp. strain IGTS8 responsible for desulfurization. A 6.7-kb TaqI fragment cloned in Escherichia coli-Rhodococcus shuttle vector pRR-6 was found to both complement this mutation and confer desulfurization to Rhodococcus fascians, which normally is not able to desulfurize DBT. Expression of this fragment in E. coli also conferred the ability to desulfurize DBT. A molecular analysis of the cloned fragment revealed a single operon containing three open reading frames involved in the conversion of DBT to 2-HBP. The three genes were designated dszA, dszB, and dszC. Neither the nucleotide sequences nor the deduced amino acid sequences of the enzymes exhibited significant similarity to sequences obtained from the GenBank, EMBL, and Swiss-Prot databases, indicating that these enzymes are novel enzymes. Subclone analyses revealed that the gene product of dszC converts DBT directly to DBT-sulfone and that the gene products of dszA and dszB act in concert to convert DBT-sulfone to 2-HBP. PMID:7574582

Radiation-induced desulfurization of Arabian crude oil and straight-run diesel

NASA Astrophysics Data System (ADS)

Basfar, A. A.; Mohamed, K. A.

2011-11-01

Radiation-induced desulfurization of four types of Arabian crude oils (heavy, medium, light and extra light) and straight-run diesel (SRD) was investigated over the range of 10-200 kGy. Results show that gamma radiation processing at absorbed doses up to 200 kGy without further treatment is not sufficient for desulfurization. However, the combination of gamma-irradiation with other physical/chemical processes (i.e. L/L extraction, adsorption and oxidation) may be capable of removing considerable levels of sulfur compounds in the investigated products. Currently, this approach of combined radiation/physical/chemical processes is under investigation. The findings of these attempts will be reported in the future.

3D CFD Modeling of the LMF System: Desulfurization Kinetics

NASA Astrophysics Data System (ADS)

Cao, Qing; Pitts, April; Zhang, Daojie; Nastac, Laurentiu; Williams, Robert

A fully transient 3D CFD modeling approach capable of predicting the three phase (gas, slag and steel) fluid flow characteristics and behavior of the slag/steel interface in the argon gas bottom stirred ladle with two off-centered porous plugs (Ladle Metallurgical Furnace or LMF) has been recently developed. The model predicts reasonably well the fluid flow characteristics in the LMF system and the observed size of the slag eyes for both the high-stirring and low-stirring conditions. A desulfurization reaction kinetics model considering metal/slag interface characteristics is developed in conjunction with the CFD modeling approach. The model is applied in this study to determine the effects of processing time, and gas flow rate on the efficiency of desulfurization in the studied LMF system.

Numerical Simulation of Desulfurization Behavior in Gas-Stirred Systems Based on Computation Fluid Dynamics-Simultaneous Reaction Model (CFD-SRM) Coupled Model

NASA Astrophysics Data System (ADS)

Lou, Wentao; Zhu, Miaoyong

2014-10-01

A computation fluid dynamics-simultaneous reaction model (CFD-SRM) coupled model has been proposed to describe the desulfurization behavior in a gas-stirred ladle. For the desulfurization thermodynamics, different models were investigated to determine sulfide capacity and oxygen activity. For the desulfurization kinetic, the effect of bubbly plume flow, as well as oxygen absorption and oxidation reactions in slag eyes are considered. The thermodynamic and kinetic modification coefficients are proposed to fit the measured data, respectively. Finally, the effects of slag basicity and gas flow rate on the desulfurization efficiency are investigated. The results show that as the interfacial reactions (Al2O3)-(FeO)-(SiO2)-(MnO)-[S]-[O] simultaneous kinetic equilibrium is adopted to determine the oxygen activity, and the Young's model with the modification coefficient R th of 1.5 is adopted to determine slag sulfide capacity, the predicted sulfur distribution ratio LS agrees well with the measured data. With an increase of the gas blowing time, the predicted desulfurization rate gradually decreased, and when the modification parameter R k is 0.8, the predicted sulfur content changing with time in ladle agrees well with the measured data. If the oxygen absorption and oxidation reactions in slag eyes are not considered in this model, then the sulfur removal rate in the ladle would be overestimated, and this trend would become more obvious with an increase of the gas flow rate and decrease of the slag layer height. With the slag basicity increasing, the total desulfurization ratio increases; however, the total desulfurization ratio changes weakly as the slag basicity exceeds 7. With the increase of the gas flow rate, the desulfurization ratio first increases and then decreases. When the gas flow rate is 200 NL/min, the desulfurization ratio reaches a maximum value in an 80-ton gas-stirred ladle.

Method and apparatus for enhancing the desulfurization of hot coal gas in a fluid-bed coal gasifier

DOEpatents

Grindley, T.

1988-04-05

A process and apparatus for providing additional desulfurization of the hot gas produced in a fluid-bed coal gasifier, within the gasifier is described. A fluid-bed of iron oxide is located inside the gasifier above the gasification bed in a fluid-bed coal gasifier in which in-bed desulfurization by lime/limestone takes place. The product gases leave the gasification bed typically at 1600 to 1800 F and are partially quenched with water to 1000 to 1200 F before entering the iron oxide bed. The iron oxide bed provides additional desulfurization beyond that provided by the lime /limestone. 1 fig.

L-proline-based deep eutectic solvents (DESs) for deep catalytic oxidative desulfurization (ODS) of diesel.

PubMed

Hao, Lingwan; Wang, Meiri; Shan, Wenjuan; Deng, Changliang; Ren, Wanzhong; Shi, Zhouzhou; Lü, Hongying

2017-10-05

A series of L-proline-based DESs was prepared through an atom economic reaction between L-proline (L-Pro) and four different kinds of organic acids. The DESs were characterized by Fourier transform infrared spectroscopy (FT-IR), H nuclear magnetic resonance ( 1 HNMR), cyclic voltammogram (CV) and the Hammett method. The synthesized DESs were used for the oxidative desulfurization and the L-Pro/p-toluenesultonic acid (L-Pro/p-TsOH) system shows the highest catalytic activity that the removal of dibenzothiophene (DBT) reached 99% at 60°C in 2h, which may involve the dual activation of the L-Pro/p-TsOH. The acidity of four different L-proline-based DESs was measured and the results show that it could not simply conclude that the correlation between the acidity of DESs and desulfurization capability was positive or negative. The electrochemical measurements evidences and recycling experiment indicate a good stability performance of L-Pro/p-TsOH in desulfurization. This work will provide a novel and potential method for the deep oxidation desulfurization. Copyright © 2017 Elsevier B.V. All rights reserved.

Experimental determination of thermodynamic equilibrium in biocatalytic transamination.

PubMed

Tufvesson, Pär; Jensen, Jacob S; Kroutil, Wolfgang; Woodley, John M

2012-08-01

The equilibrium constant is a critical parameter for making rational design choices in biocatalytic transamination for the synthesis of chiral amines. However, very few reports are available in the scientific literature determining the equilibrium constant (K) for the transamination of ketones. Various methods for determining (or estimating) equilibrium have previously been suggested, both experimental as well as computational (based on group contribution methods). However, none of these were found suitable for determining the equilibrium constant for the transamination of ketones. Therefore, in this communication we suggest a simple experimental methodology which we hope will stimulate more accurate determination of thermodynamic equilibria when reporting the results of transaminase-catalyzed reactions in order to increase understanding of the relationship between substrate and product molecular structure on reaction thermodynamics. Copyright © 2012 Wiley Periodicals, Inc.

Properties of Semi-dry Flue Gas Desulfurization Ash and Used for Phosphorus Removal

NASA Astrophysics Data System (ADS)

Yu, Y. P.; Fang, Y.; Chai, S. Y.; Zhuang, Z. Z.

2018-05-01

The composition of Semi-dry Flue Gas Desulfurization ash was as follows: CaSO3 · 0.5H2O and Ca(OH)2. Most of the particle size was about 8 µm particles were irregular and small, while the other part was rough and globular. CaSO3 strongly oxidized at about 466°C and Ca(OH)2 decomposed at ∼ 662°C. The maximum amount of phosphorus removal in Semi-dry Flue Gas Desulfurization ash was 79.898 mg/g.

[Effects of desulfurization waste on calcium distribution, Ca(2+)-ATPase activity, and antioxidant characteristics of rice leaf under alkali stress].

PubMed

Mao, Gui-Lian; Xu, Xing; Zeng, Jin; Yue, Zi-Hui; Yang, Shu-Juan

2012-02-01

To approach the action mechanisms of desulfurization waste on alleviating alkali stress-induced injury of rice, a pot experiment was conducted to study the variations of leaf total calcium content, calcium distribution, plasma membrane Ca(2+)-ATPase activity, and reactive oxygen content of rice seedlings under alkali stress after the application of desulfurization waste. In the control, a few calcium particulates scattered in the cell wall and chloroplasts, while applying desulfurization waste or CaSO4 increased the calcium particulates in the plasma membrane, intercellular space, cell wall, and vacuole significantly. With the increasing application rate of desulfurization waste or CaSO4, the leaf total calcium content increased, Ca(2+)-ATPase activity in plasma membrane and tonoplast presented an increasing trend, plasma membrane relative permeability, MDA content, and O2 production rate decreased, and SOD and POD activities increased. The desulfurization waste could relieve the alkali stress to rice in some extent, and the main reactive compound in the waste could be CaSO4.

STATUS OF COMMERCIAL UTILITY FGD (FLUE GAS DESULFURIZATION) TECHNOLOGY

EPA Science Inventory

The paper summarizes the status of FGD technology as of March 1983 and highlights recent trends in process selection, design, and performance of FGD systems. The information collected in the program is stored in the Flue Gas Desulfurization Information System (FGDIS), a collectio...

CURRENT STATUS OF ADVACATE PROCESS FOR FLUE GAS DESULFURIZATION

EPA Science Inventory

The following report discusses current bench- and pilot-plant advances in preparation of ADVAnced siliCATE (ADVACATE) calcium silicate sorbentsfor flue gas desulfurization. It also discusses current bench- and pilot-plant advances in sorbent preparation. Fly ash was ground in a l...

Desulfurizing Coal With an Alkali Treatment

NASA Technical Reports Server (NTRS)

Ravindram, M.; Kalvinskas, J. J.

1987-01-01

Experimental coal-desulfurization process uses alkalies and steam in fluidized-bed reactor. With highly volatile, high-sulfur bituminous coal, process removed 98 percent of pyritic sulfur and 47 percent of organic sulfur. Used in coal liquefaction and in production of clean solid fuels and synthetic liquid fuels. Nitrogen or steam flows through bed of coal in reactor. Alkalies react with sulfur, removing it from coal. Nitrogen flow fluidizes bed while heating or cooling; steam is fluidizing medium during reaction.

Natural desulfurization in coal-fired units using Greek lignite.

PubMed

Konidaris, Dimitrios N

2010-10-01

This paper analyzes the natural desulfurization process taking place in coal-fired units using Greek lignite. The dry scrubbing capability of Greek lignite appears to be extremely high under special conditions, which can make it possible for the units to operate within the legislative limits of sulfur dioxide (SO2) emissions. According to this study on several lignite-fired power stations in northern Greece, it was found that sulfur oxide emissions depend on coal rank, sulfur content, and calorific value. On the other hand, SO2 emission is inversely proportional to the parameter gammaCO2(max), which is equal to the maximum carbon dioxide (CO2) content by volume of dry flue gas under stoichiometric combustion. The desulfurization efficiency is positively correlated to the molar ratio of decomposed calcium carbonate to sulfur and negatively correlated to the free calcium oxide content of fly ash.

Oxidative desulfurization of dibenzothiophene from model oil using ionic liquids as extracting agent

NASA Astrophysics Data System (ADS)

Taha, Mohd F.; Atikah, N.; Chong, F. K.; Shaharun, Maizatul S.

2012-09-01

The oxidative desulfurization of dibenzothiophene (DBT) from model oil (in n-dodecane) was carried out using ionic liquid as the extractant and catalyst, and hydrogen peroxide (H2O2) in combination with acetic acid (CH3COOH) and sulphuric acid (H2SO4) as the oxidant. The ionic liquids used were 1-butyl-3-methylimidazolium octyl sulphate ([Bmim][OcSO4]) and 1-butyl-3-methylimidazolium acetate ([Bmim][Ac]). The effect of the amounts of H2O2 on oxidative desulphurization of model oil was first investigated without the usage of ionic liquids at room temperature. The results indicate that greater amount of H2O2 give higher desulfurization and the maximum desulfurization in this study, i.e. 34 %, was occurred when the molar ratio of H2O2 to sulfur was 5:1. With the usage of ionic liquid and the molar ratio of 5:1 (H2O2:sulfur), the efficiency of DBT removal from model oil was increased significantly in terms of percent removal and removal time. Ionic liquid of [Bmim][OcSO4] performed better than [Bmim][Ac] with 72 % DBT removal. When molar ratio of H2O2 to sulphur was 5:1, volume ratio of ionic liquid to model oil was 1:1 and mixing time was 60 min at room temperature. The results indicate the potential of ionic liquids as the extractant and catalyst for oxidative desulfurization of hydrocarbon fuels.

An integrated biodesulfurization process, including inoculum preparation, desulfurization and sulfate removal in a single step, for removing sulfur from oils.

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

Tangaromsuk, Jantana; Borole, Abhijeet P; Kruatrachue, Maleeya

2008-01-01

BACKGROUND: A single-stage reactor, in which the growth of bacterial culture, induction of desulfurizing enzymes, and desulfurization reaction are carried out in a single step, was adopted to investigate desulfurization of DBT at high cell densities. IGTS8 was used as the biocatalyst. Optimal condition for the bacterial growth and DBT desulfurization were also investigated. RESULTS: Optimization of fermentation conditions was necessary to obtain high cell densities including controlling accumulation of acetate. Under optimal operating conditions, the maximum OD600 was measured to be 26.6 at 118 h of cultivation. When biodesulfurization of DBT in model oil with a high cell densitymore » culture of IGTS8 was investigated, accumulation of sulfate was found to limit the extent of desulfurization. A sulfate removal step was added to obtain a single-stage integrated biodesulfurization process. Sulfate removal was achieved via an aqueous bleed stream and use of a separation unit to recycle the organic phase. CONCLUSION : A proof of principle of a complete system capable of biocatalyst growth, induction, desulfurization and by-product separation was demonstrated. This system enables simplification of the biodesulfurization process and has potential to lower the operating cost of the bioprocess.« less

Proteomics and Metabolomics Analyses to Elucidate the Desulfurization Pathway of Chelatococcus sp.

PubMed Central

Chaudhuri, Mihir K.

2016-01-01

Desulfurization of dibenzothiophene (DBT) and alkylated DBT derivatives present in transport fuel through specific cleavage of carbon-sulfur (C-S) bonds by a newly isolated bacterium Chelatococcus sp. is reported for the first time. Gas chromatography-mass spectrometry (GC-MS) analysis of the products of DBT degradation by Chelatococcus sp. showed the transient formation of 2-hydroxybiphenyl (2-HBP) which was subsequently converted to 2-methoxybiphenyl (2-MBP) by methylation at the hydroxyl group of 2-HBP. The relative ratio of 2-HBP and 2-MBP formed after 96 h of bacterial growth was determined at 4:1 suggesting partial conversion of 2-HBP or rapid degradation of 2-MBP. Nevertheless, the enzyme involved in this conversion process remains to be identified. This production of 2-MBP rather than 2-HBP from DBT desulfurization has a significant metabolic advantage for enhancing the growth and sulfur utilization from DBT by Chelatococcus sp. and it also reduces the environmental pollution by 2-HBP. Furthermore, desulfurization of DBT derivatives such as 4-M-DBT and 4, 6-DM-DBT by Chelatococcus sp. resulted in formation of 2-hydroxy-3-methyl-biphenyl and 2-hydroxy –3, 3/- dimethyl-biphenyl, respectively as end product. The GC and X-ray fluorescence studies revealed that Chelatococcus sp. after 24 h of treatment at 37°C reduced the total sulfur content of diesel fuel by 12% by per gram resting cells, without compromising the quality of fuel. The LC-MS/MS analysis of tryptic digested intracellular proteins of Chelatococcus sp. when grown in DBT demonstrated the biosynthesis of 4S pathway desulfurizing enzymes viz. monoxygenases (DszC, DszA), desulfinase (DszB), and an NADH-dependent flavin reductase (DszD). Besides, several other intracellular proteins of Chelatococcus sp. having diverse biological functions were also identified by LC-MS/MS analysis. Many of these enzymes are directly involved with desulfurization process whereas the other enzymes/proteins support

A bio-catalytic approach to aliphatic ketones.

PubMed

Xiong, Mingyong; Deng, Jin; Woodruff, Adam P; Zhu, Minshan; Zhou, Jun; Park, Sun Wook; Li, Hui; Fu, Yao; Zhang, Kechun

2012-01-01

Depleting oil reserves and growing environmental concerns have necessitated the development of sustainable processes to fuels and chemicals. Here we have developed a general metabolic platform in E. coli to biosynthesize carboxylic acids. By engineering selectivity of 2-ketoacid decarboxylases and screening for promiscuous aldehyde dehydrogenases, synthetic pathways were constructed to produce both C5 and C6 acids. In particular, the production of isovaleric acid reached 32 g/L (0.22 g/g glucose yield), which is 58% of the theoretical yield. Furthermore, we have developed solid base catalysts to efficiently ketonize the bio-derived carboxylic acids such as isovaleric acid and isocaproic acid into high volume industrial ketones: methyl isobutyl ketone (MIBK, yield 84%), diisobutyl ketone (DIBK, yield 66%) and methyl isoamyl ketone (MIAK, yield 81%). This hybrid "Bio-Catalytic conversion" approach provides a general strategy to manufacture aliphatic ketones, and represents an alternate route to expanding the repertoire of renewable chemicals.

Effect of Flue Gas Desulfurization Waste on Corn Plants

USDA-ARS?s Scientific Manuscript database

Flue gas desulfurization gypsum (FGDG) is a by-product of conversion of sulfur dioxide into solid waste from coal combustion power generation plant. This by-product is rich in calcium, magnesium, and contains various other essential plant nutrients. The beneficial use of application of this waste as...

Desulfurization of Dibenzothiophene and Diesel Oils by a Newly Isolated Gordona Strain, CYKS1

PubMed Central

Rhee, Sung-Keun; Chang, Je Hwan; Chang, Yong Keun; Chang, Ho Nam

1998-01-01

A dibenzothiophene (DBT)-desulfurizing bacterial strain was isolated and identified as Gordona strain CYKS1. Strain CYKS1 was found to transform DBT to 2-hydroxybiphenyl via the 4S pathway and to be able to also use organic sulfur compounds other than DBT as a sole sulfur source. Its desulfurization activity was susceptible to sulfate repression. Active resting cells for desulfurization could be prepared only in the early growth phase. When two types of diesel oils, middle distillate unit feed (MDUF) and light gas oil (LGO) containing various organic sulfur compounds including DBT, were treated with resting cells of strain CYKS1 for 12 h, the total sulfur content significantly decreased, from 0.15% (wt/wt) to 0.06% (wt/wt) for MDUF and from 0.3% (wt/wt) to 0.25% (wt/wt) for LGO. The newly isolated strain CYKS1 is considered to have good potential for application in the biodesulfurization of fossil fuels. PMID:9603863

Desulfurization of phosphorothioate oligonucleotides via the sulfur-by-oxygen replacement induced by the hydroxyl radical during negative electrospray ionization mass spectrometry.

PubMed

Wu, Lianming; White, David E; Ye, Connie; Vogt, Frederick G; Terfloth, Gerald J; Matsuhashi, Hayao

2012-07-01

While the occurrence of desulfurization of phosphorothioate oligonucleotides in solution is well established, this study represents the first attempt to investigate the basis of the unexpected desulfurization via the net sulfur-by-oxygen (S-O) replacement during negative electrospray ionization (ESI). The current work, facilitated by quantitative mass deconvolution, demonstrates that considerable desulfurization can take place even under common negative ESI operating conditions. The extent of desulfurization is dependent on the molar phosphorothioate oligonucleotide-to-hydroxyl radical ratio, which is consistent with the corona discharge-induced origin of the hydroxyl radical leading to the S-O replacement. This hypothesis is supported by the fact that an increase of the high-performance liquid chromatography (HPLC) flow rate and the on-column concentration of a phosphorothioate oligonucleotide, as well as a decrease of the electrospray voltage reduce the degree of desulfurization. Comparative LC-tandem mass spectrometry (MS/MS) sequencing of a phosphorothioate oligonucleotide and its corresponding desulfurization product revealed evidence that the S-O replacement occurs at multiple phosphorothioate internucleotide linkage sites. In practice, the most convenient and effective strategy for minimizing this P = O artifact is to increase the LC flow rate and the on-column concentration of phosphorothioate oligonucleotides. Another approach to mitigate possible detrimental effects of the undesired desulfurization is to operate the ESI source at a very low electrospray voltage to diminish the corona discharge; however this will significantly compromise sensitivity when analyzing the low-level P = O impurities in phosphorothioate oligonucleotides. Copyright © 2012 John Wiley & Sons, Ltd.

Chemical profiling in Moutan Cortex after sulfuring and desulfuring processes reveals further insights into the quality control of TCMs by nontargeted metabolomic analysis.

PubMed

Zhan, Zhi-Lai; Deng, Ai-Ping; Kang, Li-Ping; Tang, Jin-Fu; Nan, Tie-Gui; Chen, Tong; He, Ya-Li; Guo, Lan-Ping; Huang, Lu-Qi

2018-05-01

As a traditional processing method, sulfuring has been used in the processing of many traditional Chinese medicines (TCMs). Desulfuring, which has emerged in recent years, is a new method applied to sulfured herbs so they can comply with regulations regarding residual SO 2 . Due to the chemical transformations and the residual SO 2 in the herbs, both sulfuring and desulfuring have negative effects on the safety and therapeutic effects of TCMs, and Moutan Cortex is one of the TCMs most susceptible to these effects. Here, a new strategy was developed to differentiate normal, sulfured and desulfured Moutan Cortex, and the transformations of compounds in sulfuring and desulfuring processes were analyzed using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MSE) method based on metabolomic analysis. Our findings were as follows: (1) a total of 119 compounds were identified or tentatively identified, including 9 compounds that are being reported for the first time as natural products; (2) 15 sulfocompounds were generated during the sulfuring process; (3) these sulfocompounds could not be converted back into their corresponding glycosides by the desulfuring process, and the desulfuring decreased the residual SO 2 ,while also removing some soluble compounds in the sulfured Moutan Cortex; and (4) 28 compounds were screened and tentatively identified as markers for distinguishing normal, sulfured and desulfured Moutan Cortex. Our findings provide a new practical strategy for evaluating how sulfuring and desulfuring affect the quality of TCMs. Copyright © 2018 Elsevier B.V. All rights reserved.

Gas-exfoliated porous monolayer boron nitride for enhanced aerobic oxidative desulfurization performance.

PubMed

Wu, Yingcheng; Wu, Peiwen; Chao, Yanhong; He, Jing; Li, Hongping; Lu, Linjie; Jiang, Wei; Zhang, Beibei; Li, Huaming; Zhu, Wenshuai

2018-01-12

Hexagonal boron nitride has been regarded to be an efficient catalyst in aerobic oxidation fields, but limited by the less-exposed active sites. In this contribution, we proposed a simple green liquid nitrogen gas exfoliation strategy for preparation of porous monolayer nanosheets (BN-1). Owing to the reduced layer numbers, decreased lateral sizes and artificially-constructed pores, increased exposure of active sites was expected, further contributed to an enhanced aerobic oxidative desulfurization (ODS) performance up to ∼98% of sulfur removal, achieving ultra-deep desulfurization. This work not only introduced an excellent catalyst for aerobic ODS, but also provided a strategy for construction of some other highly-efficient monolayer two-dimensional materials for enhanced catalytic performance.

Gas-exfoliated porous monolayer boron nitride for enhanced aerobic oxidative desulfurization performance

NASA Astrophysics Data System (ADS)

Wu, Yingcheng; Wu, Peiwen; Chao, Yanhong; He, Jing; Li, Hongping; Lu, Linjie; Jiang, Wei; Zhang, Beibei; Li, Huaming; Zhu, Wenshuai

2018-01-01

Hexagonal boron nitride has been regarded to be an efficient catalyst in aerobic oxidation fields, but limited by the less-exposed active sites. In this contribution, we proposed a simple green liquid nitrogen gas exfoliation strategy for preparation of porous monolayer nanosheets (BN-1). Owing to the reduced layer numbers, decreased lateral sizes and artificially-constructed pores, increased exposure of active sites was expected, further contributed to an enhanced aerobic oxidative desulfurization (ODS) performance up to ˜98% of sulfur removal, achieving ultra-deep desulfurization. This work not only introduced an excellent catalyst for aerobic ODS, but also provided a strategy for construction of some other highly-efficient monolayer two-dimensional materials for enhanced catalytic performance.

A biocatalytic cascade with several output signals—towards biosensors with different levels of confidence

PubMed Central

Guz, Nataliia; Halámek, Jan; Rusling, James F.; Katz, Evgeny

2014-01-01

The biocatalytic cascade based on enzyme-catalyzed reactions activated by several biomolecular input signals and producing output signal after each reaction step was developed as an example of a logically reversible information processing system. The model system was designed to mimic the operation of concatenated AND logic gates with optically readable output signals generated at each step of the logic operation. Implications include concurrent bioanalyses and data interpretation for medical diagnostics. PMID:24748446

DISPOSAL OF BY-PRODUCTS FROM NONREGENERABLE FLUE GAS DESULFURIZATION SYSTEMS

EPA Science Inventory

The report gives results of a 4-year study to determine environmentally sound methods for disposing of wastes from nonregenerable flue gas desulfurization (FGD) systems. Data presented incorporates results obtained during the fourth year with material from report EPA-600/7-77-052...

A New Dry Flue Gas Desulfurization Process-Underfeed Circulating Spouted Bed

NASA Astrophysics Data System (ADS)

Tao, M.; Jin, B. S.; Yang, Y. P.

Applying an underfeed system, the underfeed circulating spouted bed was designed as a desulfurization reactor. The main objective of the technology is to improve the mixing effect and distribution uniformity of solid particles, and therefore to advance the desulfurization efficiency and calcium utility. In this article, a series of experimental studies were conducted to investigate the fluidization behavior of the solid-gas two-phase flow in the riser. The results show that the technology can distinctly improve the distribution of gas velocity and particle flux on sections compared with the facefeed style. Analysis of pressure fluctuation signals indicates that the operation parameters have significant influence on the flow field in the reaction bed. The existence of injecting flow near the underfeed nozzle has an evident effect on strengthening the particle mixing.

Bench-scale demonstration of hot-gas desulfurization technology. Quarterly report, April 1 - June 30, 1996

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

NONE

1996-12-31

The US Department of Energy (DOE) Morgantown Energy Technology Center (METC) is sponsoring research in advanced methods for controlling contaminants in hot coal gasifier gas (coal gas) streams of integrated gasification combined-cycle (IGCC) power systems. The programs focus on hot-gas particulate removal and desulfurization technologies that match or nearly match the temperatures and pressures of the gasifier, cleanup system, and power generator. The work seeks to eliminate the need for expensive heat recovery equipment, reduce efficiency losses due to quenching, and minimize wastewater treatment costs. The goal of this project is to continue further development of the zinc titanate desulfurizationmore » and direct sulfur recovery process (DSRP) technologies by (1) scaling up the zinc titanate reactor system; (2) developing an integrated skid-mounted zinc titanate desulfurization-DSRP reactor system; (3) testing the integrated system over an extended period with real coal-as from an operating gasifier to quantify the degradative effect, if any, of the trace contaminants present in cola gas; (4) developing an engineering database suitable for system scaleup; and (5) designing, fabricating and commissioning a larger DSRP reactor system capable of operating on a six-fold greater volume of gas than the DSRP reactor used in the bench-scale field test. The work performed during the April 1 through June 30, 1996 period is described.« less

Numerical Study on the Effect of Electrode Polarity on Desulfurization in Direct Current Electroslag Remelting Process

NASA Astrophysics Data System (ADS)

Wang, Qiang; Liu, Yu; Wang, Fang; Li, Guangqiang; Li, Baokuan; Qiao, Wenwei

2017-10-01

In order to clarify the influence of electrode polarity on desulfurization in direct current (DC) electroslag remelting process, a transient three-dimensional coupled mathematical model has been established. The finite volume method was invoked to simultaneously solve the mass, momentum, energy, and species conservation equations. The Joule heating and Lorentz force were fully coupled through calculating Maxwell's equations with the assistance of the magnetic potential vector. The motion of the metal-slag interface was described by using the volume of fluid approach. An auxiliary metallurgical kinetics module was introduced to determine the thermochemical and the electrochemical reaction rates. A reasonable agreement between the measured data and the simulated results are observed. A longer time and a larger area for the desulfurization can be provided by the metal pool-slag interface when compared with the metal droplet-slag interface. The electrochemical transfer rate at the metal pool-slag interface is positive in the DC reverse polarity (DCRP) remelting, while in the DC straight polarity (DCSP) remelting, the electrochemical transfer rate is negative at this interface. The desulfurization progress in the DCSP remelting thus is fall behind that in the DCRP remelting. The desulfurization rate of the DCRP remelting is around 70 pct and the rate of the DCSP remelting is about 40 pct.

Recovery of lead from lead paste in spent lead acid battery by hydrometallurgical desulfurization and vacuum thermal reduction.

PubMed

Ma, Yunjian; Qiu, Keqiang

2015-06-01

Lead sulfate, lead oxides and lead metal are the main component of lead paste in spent lead acid battery. When lead sulfate was desulfurized and transformed into lead carbonate by sodium carbonate, lead metal and lead oxides remained unchanged. Lead carbonate is easily decomposed to lead oxide and carbon dioxide under high temperature. Namely, vacuum thermal process is the reduction reaction of lead oxides. A compatible environmental process consisted of hydrometallurgical desulfurization and vacuum thermal reduction to recycle lead was investigated in this research. Lead paste was firstly desulfurized with sodium carbonate, by which, the content of sulfur declined from 7.87% to 0.26%. Then, the desulfurized lead paste was reduced by charcoal under vacuum. Under the optimized reaction conditions, i.e., vacuum thermal reduction at temperature 850°C under 20 Pa for 45 min, a 22.11×10(-2) g cm(-2) min(-1) reduction rate, and a 98.13% direct recovery ratio of fine lead (99.77%) had been achieved, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

FLUE GAS DESULFURIZATION: THE STATE OF THE ART: JOURNAL ARTICLE

EPA Science Inventory

Srivastava*, R.K., and Jozewicz, W. Flue Gas Desulfurization: The State of the Art. Journal of Air and Waste Management Association (Air & Waste Management Asiciation) 51 (12):1676-88 (2001). EPA/600/J-01/391, Available: Journal of Air and Waste Management Association (journal)...

Removal of polychlorinated naphthalenes by desulfurization and emissions of polychlorinated naphthalenes from sintering plant

PubMed Central

Wang, Mengjing; Liu, Wenbin; Hou, Meifang; Li, Qianqian; Han, Ying; Liu, Guorui; Li, Haifeng; Liao, Xiao; Chen, Xuebin; Zheng, Minghui

2016-01-01

The sintering flue gas samples were collected at the inlets and outlets of the desulfurization systems to evaluate the influence of the systems on PCNs emission concentrations, profiles, and emission factors. The PCNs concentrations at the inlets and outlets were 27888–153672 pg m−3 and 11988–42245 pg m−3,respectively. Desulfurization systems showed excellent removal for PCNs, and the removal efficiencies of PCNs increase with increasing chlorination level. Lower chlorinated homologs are more sensitive to the desulfurization process than higher ones. High levels of PCNs were also detected in the gypsum (11600–29720 pg g−1) and fly ash samples (4946–64172 pg g−1). The annual total emissions of PCNs released to flue gas and gypsum from the sintering plants were about 394 kg, 48.5% of which was in gypsum. The surface area of the fly ash samples increased significantly from the first to the fourth stage of the series-connected electrostatic precipitator, accompanying obvious rising of concentration of PCNs in the fly ash samples. PMID:27197591

Oxidative desulfurization of fuels catalyzed by Fenton-like ionic liquids at room temperature.

PubMed

Jiang, Yunqing; Zhu, Wenshuai; Li, Huaming; Yin, Sheng; Liu, Hua; Xie, Qingjie

2011-03-21

Oxidation of the sulfur-containing compounds benzothiophene (BT), dibenzothiophene (DBT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT) has been studied in a desulfurization system composed of model oil, hydrogen peroxide, and different types of ionic liquids [(C(8)H(17))(3)CH(3)N]Cl/FeCl(3), [(C(8)H(17))(3)CH(3)N]Cl/CuCl(2), [(C(8)H(17))(3)CH(3)N]Cl/ZnCl(2), [(C(8)H(17))(3)CH(3)N]Cl/SnCl(2), [(C(4)H(9))(3)CH(3)N]Cl/FeCl(3), [C(10)H(21)(CH(3))(3)N]Cl/FeCl(3), [(C(10)H(21))(2)(CH(3))(2)N]Cl/FeCl(3). Deep desulfurization is achieved in the Fenton-like ionic liquid [(C(8)H(17))(3)CH(3)N]Cl/FeCl(3) at 25 °C for 1 h. The desulfurization of DBT reaches 97.9%, in consuming very low amount of [(C(8)H(17))(3)CH(3)N]Cl/FeCl(3) (only 0.702 mmol). The reaction conditions, for example, the amount of [(C(8)H(17))(3)CH(3)N]Cl/FeCl(3) or H(2)O(2), the temperature, and the molar ratio of FeCl(3) to [(C(8)H(17))(3)CH(3)N]Cl, are investigated for this system. The oxidation reactivity of the different sulfur-containing compounds is found to decrease in the order of DBT>BT>4,6-DMDBT. The desulfurization system can be recycled six times without significant decrease in activity. The sulfur level of FCC gasoline could be reduced from 360 ppm to 110 ppm. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Diversity analysis of desulfuration bacterium from the oxidation ditch of city sewage treatment plant with SO2 gas].

PubMed

Huang, Bing; Zhang, Shi-Ling; Zhang, Jiang-Hong; Ao, Yong; Shi, Zhe

2011-07-01

A group of removing SO2 bacterium was obtained from the oxidation ditch of city sewage treatment plant by inductive domestication over 6 d with low concentration SO2 gas, and they have an ability with biodegradation rate of 888 mg x (L x h)(-1) and a degradation efficiency of 85% during 1.5 h for SO2 dissolved in water with their synergy. The clone library and two phylogenetic trees of the removing SO2 bacterium communities were obtained based on 16S rRNA DNA comparison by DNA extraction of the sample and in situ polymerase chain reaction (PCR). The phylogenetic analysis showed that 8 dominant desulfuration bacterium occupy about 69% of all removing SO2 bacterium, and some of them have a kindred with discovered desulfuration bacterium but not homogeneity, and there are four belong to alpha-Proteobacteria, another four belong to beta-Proteobacteria in them. The gene information about 16S rRNA sequence of the dominant desulfuration bacteria and domestication method provide a basic of looking for or domesticating removing SO2 bacterium for development microbial desulfurization technology of contained SO2 tail gas.

Core-in-shell sorbent for hot coal gas desulfurization

DOEpatents

Wheelock, Thomas D.; Akiti, Jr., Tetteh T.

2004-02-10

A core-in-shell sorbent is described herein. The core is reactive to the compounds of interest, and is preferably calcium-based, such as limestone for hot gas desulfurization. The shell is a porous protective layer, preferably inert, which allows the reactive core to remove the desired compounds while maintaining the desired physical characteristics to withstand the conditions of use.

Investigation Of A Mercury Speciation Technique For Flue Gas Desulfurization Materials

EPA Science Inventory

Most of the synthetic gypsum generated from wet flue gas desulfurization (FGD) scrubbers is currently being used for wallboard production. Because oxidized mercury is readily captured by the wet FGD scrubber, and coal-fired power plants equipped with wet scrubbers desire to bene...

Reusing pretreated desulfurization slag to improve clinkerization and clinker grindability for energy conservation in cement manufacture.

PubMed

Chen, Ying-Liang; Chang, Juu-En; Shih, Pai-Haung; Ko, Ming-Sheng; Chang, Yi-Kuo; Chiang, Li-Choung

2010-09-01

The purpose of this study was to combine the physical pretreatments of grinding, sieving, and magnetic-separation processes to reclaim iron-rich materials from the desulfurization slag, and to use the remainder for cement clinker production. The iron-rich materials can be separated out efficiently by grinding for 30 min and sieving with a 0.3 mm mesh. The non-magnetic fraction of the particles smaller than 0.3 mm was in the majority, and proved to be suitable for use as a cement raw material. The raw mixes prepared with a pretreated desulfurization slag had a relatively high reactivity, and the temperature at which alite forms was significantly reduced during the clinkerization process. The clinkers produced with 10% desulfurization slag had a high level of alite and good grindability. Generally, the improvements in clinkerization and clinker grindability are beneficial to energy conservation in cement manufacture. 2010 Elsevier Ltd. All rights reserved.

Ultrasensitive aptamer-based protein detection via a dual amplified biocatalytic strategy

PubMed Central

Xiang, Yun; Zhang, Yuyong; Qian, Xiaoqing; Chai, Yaqin; Wang, Joseph; Yuan, Ruo

2010-01-01

We present an ultrasensitive aptasensor for electronic monitoring of proteins through a dual amplified strategy in this paper. The target protein thrombin is sandwiched between an electrode surface confined aptamer and an aptamer-enzyme-carbon nanotube bioconjugate. The analytical signal amplification is achieved by coupling the signal amplification nature of multiple enzymes with the biocatalytic signal enhancement of redox-recycling. Our novel dramatic signal amplification strategy, with a detection limit of 8.3 fM, shows about 4 orders of magnitude improvement in sensitivity for thrombin detection compared to other universal single enzyme-based assay. This makes our approach an attractive alternative to other common PCR-based signal amplification in ultralow level of protein detection. PMID:20452761

Microbial Desulfurization of Gasoline in a Mycobacterium goodii X7B Immobilized-Cell System

PubMed Central

Li, Fuli; Xu, Ping; Feng, Jinhui; Meng, Ling; Zheng, Yuan; Luo, Lailong; Ma, Cuiqing

2005-01-01

Mycobacterium goodii X7B, which had been primarily isolated as a bacterial strain capable of desulfurizing dibenzothiophene to produce 2-hydroxybiphenyl via the 4S pathway, was also found to desulfurize benzothiophene. The desulfurization product was identified as o-hydroxystyrene by gas chromatography (GC)-mass spectrometry analysis. This strain appeared to have the ability to remove organic sulfur from a broad range of sulfur species in gasoline. When Dushanzi straight-run gasoline (DSRG227) containing various organic sulfur compounds was treated with immobilized cells of strain X7B for 24 h, the total sulfur content significantly decreased, from 227 to 71 ppm at 40°C. GC flame ionization detection and GC atomic emission detection analysis were used to qualitatively evaluate the effects of M. goodii X7B treatment on the contents of gasoline. In addition, when immobilized cells were incubated at 40°C with DSRG275, the sulfur content decreased from 275 to 54 ppm in two consecutive reactions. With this excellent efficiency, strain X7B is considered a good potential candidate for industrial applications for the biodesulfurization of gasoline. PMID:15640198

Photooxidative desulfurization for diesel using Fe / N - TiO2 photocatalyst

NASA Astrophysics Data System (ADS)

Khan, Muhammad Saqib; Kait, Chong Fai; Mutalib, Mohd Ibrahim Abdul

2014-10-01

A series of N - TiO2 with different mol% N was synthesized via sol-gel method and characterized using thermal gravimetric analyzer and raman spectroscopy. 0.2 wt% Fe was incorporated onto the calcined (200°C) N - TiO2 followed by calcination at 200°C, 250°C and 300°C. Photooxidative desulfurization was conducted in the presence of 0.2wt% Fe / N - TiO2 with different mol% N with and without oxidant (H2O2). Oxidative desulfurization was only achieved when H2O2 was used while without H2O2 no major effect on the sulfur removal. 0.2Fe -30N - H2O2 photocatalysts showed best performance at all calcination temperatures as compared to other mol% N - H2O2 photocatalysts. 16.45% sulfur removal was achieved using photocatalysts calcined at 300 °C.

A recyclable ionic liquid-oxomolybdenum(vi) catalytic system for the oxidative desulfurization of model and real diesel fuel.

PubMed

Julião, Diana; Gomes, Ana C; Pillinger, Martyn; Valença, Rita; Ribeiro, Jorge C; Gonçalves, Isabel S; Balula, Salete S

2016-10-14

The oxidative desulfurization of model and real diesel has been studied using the complex [MoO2Cl2(4,4'-di-tert-butyl-2,2'-bipyridine)] as (pre)catalyst, aq. H2O2 as oxidant, and an ionic liquid as extraction solvent. Under moderate conditions (50 °C) and short reaction times (<3 h), dibenzothiophene, 4-methyldibenzothiophene and 4,6-dimethyldibenzothiophene could be completely removed from the model diesel. The (pre)catalyst 1 was transformed in situ to the active catalyst [MoO(O2)2(di-tBu-bipy)]. By sequentially performing extractive desulfurization and ECODS steps, 76% sulfur removal was achieved for a real diesel (Sinitial = 2300 ppm). For both the model and real diesels, the catalyst/IL phase could be easily recycled and reused with no loss of desulfurization efficiency.

Mathematical Modeling Of Production Of Bio-surfactant Through Bio-desulfurization Of Hydrotreated Diesel In A Fermenter

NASA Astrophysics Data System (ADS)

Bandyopadhyay, Sujaya; Chowdhury, Ranjana; Bhattacharjee, Chiranjib

2010-10-01

The conventional deep desulfurization must be followed by a suitable desulfurization process to achieve ultra low sulfur diesel (ULSD) with 10-15 ppm sulfur level which satisfies the strict environmental regulations. Bio-desulfurization is one of the potential routes for the above mentioned purpose. In this present investigation our major concern is production of Ultra Low sulfur diesel (ULSD) and production of biosurfactant simultaneously using Rhodococcus sp. The substituted benzothiophenes (BTs) and dibenzothiophenes (DBTs) get converted to 2-hydroxy biphenyl, which is a potential bio-surfactant. Kinetics of biodesulfurisation of deep desulfurized diesel using Rhodococcus sp. has been studied with special reference to removal of organo-sulfur compounds in diesel and production of 2-hydroxy biphenyl. The sulfur concentration of feed diesel is in the range of 200-540 mg/L. Aqueous phase to diesel ratios have been varied in the range of 9:1 to 1:9. The optimum ratio has been found to be 1:4 and the maximum conversion of sulfur of 95% has been achieved. The values of Monod kinetic parameters, μmax, maximum specific growth rate and Ks, saturation constant of the microbial growth and Yield coefficient of surfactant have been measured to be 0.096 h-1, 71 mg/L, and 17 μmol/g dry cell weights respectively by conducting batch type experiments. A deterministic mathematical model has been developed using the kinetic parameters and the experimental data have been compared with simulated ones satisfactorily.

PROCEEDINGS: SYMPOSIUM ON FLUE GAS DESULFURIZATION - NEW ORLEANS, MARCH 1976, VOLUME I

EPA Science Inventory

The proceedings document the presentation made during the symposium, which dealt with the status of flue gas desulfurization technology in the United States and abroad. Subjects considered included: regenerable, nonregenerable, and advanced processes; process costs; and by-produc...

Synthesis, Characterization and Application of 1-Butyl-3 Methylimidazolium Chloride as Green Material for Extractive Desulfurization of Liquid Fuel

PubMed Central

Dharaskar, Swapnil A.; Varma, Mahesh N.; Shende, Diwakar Z.; Yoo, Chang Kyoo; Wasewar, Kailas L.

2013-01-01

The possible application of imidazolium ionic liquids as energy-efficient green material for extractive deep desulfurization of liquid fuel has been investigated. 1-Butyl-3-methylimidazolium chloride [BMIM]Cl was synthesized by nucleophilic substitution reaction of n-methylimidazolium and 1-chlorobutane. Molecular structures of the ILs were confirmed by FTIR, 1H-NMR, and 13C-NMR. The thermal properties, conductivity, solubility, water content and viscosity analysis of [BMIM]Cl were carried out. The effects of reaction time, reaction temperature, sulfur compounds, and recycling of IL without regeneration on dibenzothiophene removal of liquid fuel were presented. In the extractive desulfurization process, the removal of dibenzothiophene in n-dodecane using [BMIM]Cl was 81% with mass ratio of 1 : 1, in 30 min at 30°C under the mild reaction conditions. Also, desulfurization of real fuels with IL and multistage extraction were studied. The results of this work might offer significant insights in the perceptive use of imidazoled ILs as energy-efficient green material for extractive deep desulfurization of liquid fuels as it can be reused without regeneration with considerable extraction efficiency. PMID:24307868

PROCEEDINGS: SYMPOSIUM ON FLUE GAS DESULFURIZATION-NEW ORLEANS, MARCH 1976. VOLUME II

EPA Science Inventory

The proceedings document the presentations made during the symposium, which dealt with the status of flue gas desulfurization technology in the United States and abroad. Subjects considered included: regenerable, non-regenerable, and advanced processes; process costs; and by-prod...

Hydrologic transport of fecal bacteria attenuated by flue gas desulfurization gypsum

USDA-ARS?s Scientific Manuscript database

Flue gas desulfurization (FGD) gypsum is a byproduct of coal-fired power plants. As a soil amendment for crop and pasture production it may increase water infiltration, reduce soil erosion, and decrease nutrient losses from applications of animal manures. Broiler litter is used as a source of plan...

Desulfurization characteristics of rapidly hydrated sorbents with various adhesive carrier particles for a semidry CFB-FGD system.

PubMed

You, Changfu; Li, Yuan

2013-03-19

Semidry flue gas desulfurization (FGD) experiments were conducted using rapidly hydrated sorbents with four different adhesive carrier particles: circulation ash from a circulating fluidized bed boiler (CFBB circulation ash), fly ash from the first electrical field of the electrostatic precipitator of a circulating fluidized bed boiler (CFBB ESP ash), fly ash from a chain boiler (chain boiler ash), and river sand smaller than 1 mm. The influences of various adhesive carrier particles and operating conditions on the desulfurization characteristics of the sorbents were investigated, including sprayed water, reaction temperature, and the ratio of calcium to sulfur (Ca/S). The experimental results indicated that the rapidly hydrated sorbents had better desulfurization characteristics by using adhesive carrier particles which possessed better pore, adhesion, and fluidization characteristics. The desulfurization efficiency of the system increased as the reaction temperature decreased, it improved from 35% to 90% as the mass flow rate of the sprayed water increased from 0 to 10 kg/h, and it increased from 65.6% to 82.7% as Ca/S increased from 1.0 to 2.0. Based on these findings, a new semidry circulating fluidized bed (CFB)-FGD system using rapidly hydrated sorbent was developed. Using the rapidly hydrated sorbent, this system uses a cyclone separator instead of an ESP or a bag filter to recycle the sorbent particles, thereby decreasing the system flow resistance, saving investment and operating costs of the solids collection equipment.

Desulfurization Activated Phosphorothioate DNAzyme for the Detection of Thallium.

PubMed

Huang, Po-Jung Jimmy; Vazin, Mahsa; Liu, Juewen

2015-10-20

Thallium (Tl) is a highly toxic heavy metal situated between mercury and lead in the periodic table. While its neighbors have been thoroughly studied for DNA-based sensing, little is known about thallium detection. In this work, in vitro selection of RNA-cleaving DNAzymes is carried out using Tl(3+) as the target metal cofactor. Both normal DNA and phosphorothioate (PS)-modified DNA are tested for this purpose. While no Tl(3+)-dependent DNAzymes are obtained, a DNA oligonucleotide containing a single PS-modified RNA nucleotide is found to cleave by ∼7% by Tl(3+) at the RNA position. The remaining 93% are desulfurized. By hybridization of this PS-modified oligonucleotide with the Tm7 DNAzyme, the cleavage yield increases to ∼40% in the presence of Tl(3+) and Er(3+). Tm7 is an Er(3+)-dependent RNA-cleaving DNAzyme. It cleaves only the normal substrate but is completely inactive using the PS-modified substrate. Tl(3+) desulfurizes the PS substrate to the normal substrate to be cleaved by Tm7 and Er(3+). This system is engineered into a catalytic beacon for Tl(3+) with a detection limit of 1.5 nM, which is below its maximal contamination limit defined by the U.S. Environmental Protection Agency (10 nM).

Enzymatic desulfurization of coal: Third quarterly report

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

Marquis, Judith K.; Kitchell, Judith P.

Our current efforts to develop clean coal technology emphasize the advantages of enzymatic desulfurization techniques and have specifically addressed the potential of using partially-purified extracellular microbial enzymes or commercially available enzymes. Our work is focused on the treatment of ''model'' organic sulfur compounds such as dibenzothiophene (DBT) and ethylphenylsulfide (EPS). Furthermore, we are designing experiments to facilitate the enzymatic process by means of a hydrated organic solvent matrix. In this quarter we obtained important results both with the development of our understanding of the enzyme reaction systems and also with the microbial work at Woods Hole. 12 figs., 11 tabs.

Sorbent for use in hot gas desulfurization

DOEpatents

Gasper-Galvin, Lee D.; Atimtay, Aysel T.

1993-01-01

A multiple metal oxide sorbent supported on a zeolite of substantially silicon oxide is used for the desulfurization of process gas streams, such as from a coal gasifier, at temperatures in the range of about 1200.degree. to about 1600.degree. F. The sorbent is provided by a mixture of copper oxide and manganese oxide and preferably such a mixture with molybdenum oxide. The manganese oxide and the molybdenum are believed to function as promoters for the reaction of hydrogen sulfide with copper oxide. Also, the manganese oxide inhibits the volatilization of the molybdenum oxide at the higher temperatures.

MODELING OF SO2 REMOVAL IN SPRAY-DRYER FLUE-GAS DESULFURIZATION SYSTEM

EPA Science Inventory

The report presents a comprehensive mathematical model of the SO2 removal process in a spray-dryer flue-gas desulfurization system. Simultaneous evaporation of a sorbent droplet and absorption/reaction of SO2 in the droplet are described by the corresponding heat- and mass-transf...

Highly flexible sub-1 nm tungsten oxide nanobelts as efficient desulfurization catalysts.

PubMed

He, Jie; Liu, Huiling; Xu, Biao; Wang, Xun

2015-03-01

Ultrathin tungsten oxide nanobelts are successfully synthesized via a facile solvothermal method. Sub-1 nm thickness and hydrophobic surface property endow the nanobelts with flexibility, viscosity, gelation, and good catalytic performance in oxidative desulfurization. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

SURVEY OF FLUE GAS DESULFURIZATION SYSTEMS: ST. CLAIR STATION, DETROIT EDISON CO

EPA Science Inventory

The report gives results of a survey of the flue gas desulfurization (FGD) system retrofitted on Unit 6 of Detroit Edison Co.'s St. Clair Station. The experimental FGD system, which operated through a 2-month (October 1976-January 1977) demonstration program, utilized a limestone...

Hydrologic transport of fecal bacteria attenuated by flu gas desulfurized (FGD) gypsum

USDA-ARS?s Scientific Manuscript database

Background Flue gas desulfurized (FGD) gypsum is a byproduct of coal-fired power plants. As a soil amendment for crop production it has the potential of improving soil water infiltration, soil conservation, and decreasing nutrient losses from broiler litter applications. Because broiler litter is a ...

Decreasing phosphorus loss in tile-drained landscapes using flue gas desulfurization gypsum

USDA-ARS?s Scientific Manuscript database

Elevated phosphorus (P) loading from agricultural non-point source pollution continues to impair inland waterbodies throughout the world. The application of flue gas desulfurization (FGD) gypsum to agricultural fields has been suggested to decrease P loading because of its high calcium content and P...

Ultrasound-assisted oxidative desulfurization process of liquid fuel by phosphotungstic acid encapsulated in a interpenetrating amine-functionalized Zn(II)-based MOF as catalyst.

PubMed

Afzalinia, Ahmad; Mirzaie, Abbas; Nikseresht, Ahmad; Musabeygi, Tahereh

2017-01-01

In this work, ultrasound-assisted oxidative desulfurization (UAOD) of liquid fuels performed with a novel heterogeneous highly dispersed Keggin-type phosphotungstic acid (H 3 PW 12 O 40 , PTA) catalyst that encapsulated into an amino-functionalized MOF (TMU-17-NH 2 ). The prepared composite exhibits high catalytic activity and reusability in oxidative desulfurization of model fuel. Ultrasound-assisted oxidative desulfurization (UAOD) is a new way to performed oxidation reaction of sulfur-contain compounds rapidly, economically, environment-friendly and safely, under mild conditions. Ultrasound waves can be apply as an efficient tool to decrease the reaction time and improves oxidative desulfurization system performance. PTA@TMU-17-NH 2 could be completely performed desulfurization of the model oil by 20mg of catalyst, O/S molar ratio of 1:1 in presence of MeCN as extraction solvent. The obtained results indicated that the conversions of DBT to DBTO 2 achieve 98% after 15min in ambient temperature. In this work, we prepared TMU-17-NH 2 and PTA/TMU-17-NH 2 composite by ultrasound irradiation for first time and employed in UAOD process. Prepared catalyst exhibit an excellent reusability without PTA leaching and loss of activity. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

[Domestication study about desulfuration microorganism from oxidation ditch by low concentration SO2].

PubMed

Huang, Bing; Shi, Zhe; Wang, Yan-Yan; Zhang, Shi-Ling

2010-06-01

An excellent desulfuration microorganism with a quick growth and propagation, high activation, high efficiency of removing SO2 is obtained from oxidation ditch of a city sewage treatment plant by inductive acclimatization over 6 d with low concentration SO2 gas (100-2 000 mg/m3). The desulfurition microorganism get their energy sources for growth from transforming SO2 (SO3(2-)) to SO4(2-). The predominant bacterium of the desulfuration microorganism has the same characteristic with Thiobacillus ferrooxidans (T. ferrooxidans), which showed that it was Gram negative, short rod bacteria with a single polar flagellum under a microscopic examination, and obtained its nourishment through the oxidation of inorganic compounds. The technology process condition of domestication and desulfuration of microorganism are particular studied, and the results showed that aerating time, SO2 flux and time to provide nutriment contained N, P, K to microorganism were very important. They have an ability with degradation rate of 160g/ (m3 x h) and degradation efficiency over 50% to transform sulfite to sulfate in liquid phase. The bacteria have a 98% of removing efficiency and over 80% of biodegradation efficiency for the 5 500 mg/m3 SO2 gas and the outlet concentration of SO2 is lower than 100 mg/m3, and also have a 95% of removing efficiency for 15 000 mg/m3 SO2 gas in the packed tower reactor with Raschig ring at 3s contact time.

1,3-Diferuloyl-sn-glycerol from the biocatalytic transesterification of ethyl 4-hydroxy-3-methoxy cinnamic acid (ethyl ferulate) and soybean oil

USDA-ARS?s Scientific Manuscript database

1,3-Diferuloyl-sn-glycerol is a natural plant component found ubiquitously throughout the plant kingdom, possessing ultraviolet adsorbing and antioxidant properties. Diferuloyl glycerol was synthesized and isolated as a byproduct in up to 5% yield from the pilot plant scale packed-bed, biocatalytic...

Results using flue gas desulfurization gypsum in soilless substrates for greenhouse crops

USDA-ARS?s Scientific Manuscript database

Recent availability of Flue Gas Desulfurization gypsum (FGDG) has led to interested in its possible use in horticulture greenhouse production. Three studies were conducted to determine the effects of increasing rates of FGDG on six greenhouse crops. In the first study, substrates (6:1 pine bark:san...

Ultrasound-assisted oxidative desulfurization of liquid fuels and its industrial application.

PubMed

Wu, Zhilin; Ondruschka, Bernd

2010-08-01

Latest environmental regulations require a very deep desulfurization to meet the ultra-low sulfur diesel (ULSD, 15 ppm sulfur) specifications. Due to the disadvantages of hydrotreating technology on the slashing production conditions, costs and safety as well as environmental protection, the ultrasound-assisted oxidative desulfurization (UAOD) as an alternative technology has been developed. UAOD process selectively oxidizes sulfur in common thiophenes in diesel to sulfoxides and sulfones which can be removed via selective adsorption or extractant. SulphCo has successfully used a 5000 barrel/day mobile "Sonocracking" unit to duplicate on a commercial scale its proprietary process that applies ultrasonics at relatively low temperatures and pressures. The UAOD technology estimate capital costs less than half the cost of a new high-pressure hydrotreater. The physical and chemical mechanisms of UAOD process are illustrated, and the effective factors, such as ultrasonic frequency and power, oxidants, catalysts, phase-transfer agent, extractant and adsorbent, on reaction kinetics and product recovery are discussed in this review. Copyright 2009 Elsevier B.V. All rights reserved.

Biocatalytic synthesis of the Green Note trans-2-hexenal in a continuous-flow microreactor.

PubMed

van Schie, Morten M C H; Pedroso de Almeida, Tiago; Laudadio, Gabriele; Tieves, Florian; Fernández-Fueyo, Elena; Noël, Timothy; Arends, Isabel W C E; Hollmann, Frank

2018-01-01

The biocatalytic preparation of trans -hex-2-enal from trans -hex-2-enol using a novel aryl alcohol oxidase from Pleurotus eryngii ( Pe AAOx) is reported. As O 2 -dependent enzyme Pe AAOx-dependent reactions are generally plagued by the poor solubility of O 2 in aqueous media and mass transfer limitations resulting in poor reaction rates. These limitations were efficiently overcome by conducting the reaction in a flow-reactor setup reaching unpreceded catalytic activities for the enzyme in terms of turnover frequency (up to 38 s -1 ) and turnover numbers (more than 300000) pointing towards preparative usefulness of the proposed reaction scheme.

Effects of magnetic fields on improving mass transfer in flue gas desulfurization using a fluidized bed

NASA Astrophysics Data System (ADS)

Zhang, Qi; Gui, Keting; Wang, Xiaobo

2016-02-01

The effects of magnetic fields on improving the mass transfer in flue gas desulfurization using a fluidized bed are investigated in the paper. In this research, the magnetically fluidized bed (MFB) is used as the reactor in which ferromagnetic particles are fluidized with simulated flue gas under the influence of an external magnetic field. Lime slurry is continuously sprayed into the reactor. As a consequence, the desulfurization reaction and the slurry drying process take place simultaneously in the MFB. In this paper, the effects of ferromagnetic particles and external magnetic fields on the desulphurization efficiency are studied and compared with that of quartz particles as the fluidized particles. Experimental results show that the ferromagnetic particles not only act as a platform for lime slurry to precipitate on like quartz particles, but also take part in the desulfurization reaction. The results also show that the specific surface area of ferromagnetic particles after reaction is enlarged as the magnetic intensity increases, and the external magnetic field promotes the oxidation of S(IV), improving the mass transfer between sulphur and its sorbent. Hence, the efficiency of desulphurization under the effects of external magnetic fields is higher than that in general fluidized beds.

SURVEY OF FLUE GAS DESULFURIZATION SYSTEMS: WILL COUNTY STATION, COMMONWEALTH EDISON CO

EPA Science Inventory

The report gives results of a second survey of the flue gas desulfurization (FGD) system on Unit 1 of Commonwealth Edison Co.'s Will County Station. The FGD system, started up in February 1972, uses a limestone slurry in two parallel scrubbing trains. Each train includes a ventur...

Biocatalytic nerve agent detoxification in fire fighting foams.

PubMed

LeJeune, K E; Russell, A J

1999-03-20

Current events across the globe necessitate rapid technological advances to combat the epidemic of nerve agent chemical weapons. Biocatalysis has emerged as a viable tool in the detoxification of organophosphorus neurotoxins, such as the chemical weapons VX and sarin. Efficient detoxification of contaminated equipment, machinery, and soils are of principal concern. This study describes the incorporation of a biocatalyst (organophosphorus hydrolase, E.C. 3.1.8.1) into conventional formulations of fire fighting foam. The capacity of fire fighting foams to decrease volatilization of contained contaminants, increase surface wettability, and control the rate of enzyme delivery to large areas makes them useful vehicles for enzyme application at surfaces. The performance of enzyme containing foams has been shown to be not only reproducible but also predictable. An empirical model provides reasonable estimations for the amounts of achievable surface decontamination as a function of the important parameters of the system. Theoretical modeling illustrates that the enzyme-containing foam is capable of extracting agent from the surface and is catalytically active at the foam-surface interface and throughout the foam itself. Biocatalytic foam has proven to be an effective, "environmentally friendly" means of surface and soil decontamination.

Oxidative desulfurization of model diesel via dual activation by a protic ionic liquid.

PubMed

Lü, Hongying; Wang, Shunan; Deng, Changliang; Ren, Wanzhong; Guo, Baocun

2014-08-30

A novel and green carboxylate-anion-based protic ionic liquid (PIL), [Hnmp]HCOO, was prepared through a simple and atom economic neutralization reaction between N-methyl-2-pyrrolidonium (NMP) and formic acids. Both FT-IR spectra and (1)H NMR confirmed its simple salt structure. [Hnmp]HCOO exhibited so high catalytic activity that the dibenzothiophene (DBT) removal reached 99% at 50°C in 3h under conditions of VPIL/Vmodel oil=1:10 and H2O2/DBT (O/S, molar ratio)=5. The catalytic oxidation reactivity of S-compounds was found to be in the order of DBT>4,6-dimethyldibenzothiophene (4,6-DMDBT)>benzothiophene (BT). The investigation on mechanism showed that oxidative desulfurization was realized through dual activation of PIL. Moreover, [Hnmp]HCOO can be recycled for five times with an unnoticeable decrease in desulfurization activity. Copyright © 2014 Elsevier B.V. All rights reserved.

Flue gas desulfurization chemistry studies: limestone grindability. Volume 1. FGD reagent mapping. Final report

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

Richmann, D.L.; Rossi, J.P.; Rashin, E.B.

1984-07-01

The major objective of this project is to provide electric utilities with information concerning the availability of flue gas desulfurization (FGD) system reagents. Data presented in this report were obtained primarily from a comprehensive review of available literature. These were augmented by information gathered through interviews with knowledgeable individuals from industry, government, and academic institutions. Limestone data are presented on regional and state maps displaying, respectively, annual limestone production and number of active quarries by county; and areas most likely to contain potentially commercial deposits of high-Ca (greater than or equal to 90% CaCO/sub 3/) limestone. Lime data are presentedmore » on regional maps indicating ranges of annual production and number of active lime plants by county. Identification of commercial versus captive operations and estimates of lime availability on the open market are summarized in tables accompanying each map.« less

PROCEEDINGS: SYMPOSIUM ON FLUE GAS DESULFURIZATION HELD AT HOLLYWOOD, FLORIDA, NOVEMBER 1977. VOLUME II

EPA Science Inventory

The proceedings document presentations made during the symposium, which dealt with the status of flue gas desulfurization technology in the United States and abroad. Subjects considered included: regenerable, non-regenerable, and advanced processes; process costs; and by-product ...

PROCEEDINGS: SYMPOSIUM ON FLUE GAS DESULFURIZATION HELD AT HOLLYWOOD, FLORIDA, NOVEMBER 1977. VOLUME I

EPA Science Inventory

The proceedings document presentations made during the symposium, which dealt with the status of flue gas desulfurization technology in the United States and abroad. Subjects considered included: regenerable, non-regenerable, and advanced processes; process costs; and by-product ...

Biocatalytic synthesis of the Green Note trans-2-hexenal in a continuous-flow microreactor

PubMed Central

van Schie, Morten M C H; Pedroso de Almeida, Tiago; Laudadio, Gabriele; Tieves, Florian; Fernández-Fueyo, Elena; Arends, Isabel W C E

2018-01-01

The biocatalytic preparation of trans-hex-2-enal from trans-hex-2-enol using a novel aryl alcohol oxidase from Pleurotus eryngii (PeAAOx) is reported. As O2-dependent enzyme PeAAOx-dependent reactions are generally plagued by the poor solubility of O2 in aqueous media and mass transfer limitations resulting in poor reaction rates. These limitations were efficiently overcome by conducting the reaction in a flow-reactor setup reaching unpreceded catalytic activities for the enzyme in terms of turnover frequency (up to 38 s−1) and turnover numbers (more than 300000) pointing towards preparative usefulness of the proposed reaction scheme. PMID:29719567

Investigations in physical mechanism of the oxidative desulfurization process assisted simultaneously by phase transfer agent and ultrasound.

PubMed

Bhasarkar, Jaykumar B; Chakma, Sankar; Moholkar, Vijayanand S

2015-05-01

This paper attempts to discern the physical mechanism of the oxidative desulfurization process simultaneously assisted by ultrasound and phase transfer agent (PTA). With different experimental protocols, an attempt is made to deduce individual beneficial effects of PTA and ultrasound on the oxidative desulfurization system, and also the synergy between the effects of PTA and ultrasound. Effect of PTA is more marked for mechanically stirred system due to mass transfer limitations, while intense emulsification due to ultrasound helps overcome the mass transfer limitations and reduces the extent of enhancement of oxidation by PTA. Despite application of PTA and ultrasound, the intrinsic factors and properties of the reactants such as polarity (and hence partition coefficient) and diffusivity have a crucial effect on the extent of oxidation. The intrinsic reactivity of the oxidant also plays a vital role, as seen from the extent of oxidation achieved with performic acid and peracetic acid. The interfacial transport of oxidant in the form of oxidant-PTA complex reduces the undesired consumption of oxidant by the reducing species formed during transient cavitation in organic medium, which helps effective utilization of oxidant towards desulfurization. Copyright © 2014 Elsevier B.V. All rights reserved.

Enhancing mercury removal across air pollution control devices for coal-fired power plants by desulfurization wastewater evaporation.

PubMed

Bin, Hu; Yang, Yi; Cai, Liang; Yang, Linjun; Roszak, Szczepan

2017-10-09

Desulfurization wastewater evaporation technology is used to enhance the removal of gaseous mercury (Hg) in conventional air pollution control devices (APCDs) for coal-fired power plants. Studies have affirmed that gaseous Hg is oxidized and removed by selective catalytic reduction (SCR), an electrostatic precipitator (ESP) and wet flue gas desulfurization (WFGD) in a coal-fired thermal experiment platform with WFGD wastewater evaporation. Effects of desulfurization wastewater evaporation position, evaporation temperature and chlorine ion concentration on Hg oxidation were studied as well. The Hg 0 oxidation efficiency was increased ranging from 30% to 60%, and the gaseous Hg removal efficiency was 62.16% in APCDs when wastewater evaporated before SCR. However, the Hg 0 oxidation efficiency was 18.99% and the gaseous Hg removal efficiency was 40.19% in APCDs when wastewater evaporated before ESP. The results show that WFGD wastewater evaporation before SCR is beneficial to improve the efficiency of Hg oxidized and removed in APCDs. Because Hg 2+ can be easily removed in ACPDs and WFGD wastewater in power plants is enriched with chlorine ions, this method realizes WFGD wastewater zero discharge and simultaneously enhances Hg removal in APCDs.

Deep Desulfurization of Diesel Fuels with Plasma/Air as Oxidizing Medium, Diperiodatocuprate (III) as Catalyzer and Ionic Liquid as Extraction Solvent

NASA Astrophysics Data System (ADS)

Ban, Lili; Liu, Ping; Ma, Cunhua; Dai, Bin

2013-12-01

In this paper, the oxidative desulfurization (ODS) system is directly applied to deal with the catalytic oxidation of sulfur compounds of sulfur-containing model oil by dielectric barrier discharge (DBD) plasma in the presence of air plus an extraction step with the oxidation-treated fuel put over ionic liquid [BMIM]FeCl4 (1-butyl-3-methylimidazolium tetrachloroferrate). This new system exhibited an excellent desulfurization effect. The sulfur content of DBT in diesel oil decreased from 200 ppm to 4.92 ppm (S removal rate up to 97.5%) under the following optimal reaction conditions: air flow rate (ν) of 60 mL/min, amplitude of applied voltage (U) on DBD of 16 kV, input frequency (f) of 79 kHz, catalyst amount (ω) of 1.25 wt%, reaction time (t) of 10 min. Moreover, a high desulfurization rate was obtained during oxidation of benzothiophene (BT) or 4,6-DMDBT (4,6-dimethyl-dibenzothiophene) under the aforementioned conditions. The oxidation reactivity of different S compounds was decreased in the order of DBT, 4,6-DMDBT and BT. The remarkable advantage of the novel ODS system is that the desulfurization condition applies in the presence of air at ambient conditions without peroxides, aqueous solvent or biphasic oil-aqueous solution system.

Desulfurization of 4-methyl dibenzothiophene using titanium supported Keggin type polyoxometalate

NASA Astrophysics Data System (ADS)

Lesbani, Aldes; Anggraini, Ana; Mohadi, Risfidian; Rohendi, Dedi; Said, Muhammad

2017-03-01

Titanium supported Keggin type polyoxometalate H5PV2Mo10O40.nH2O has been prepared using tetra isopropyl orthotitanate by sol-gel method and microemulsion to form H5PV2Mo10O40/TiO2. Compound H5PV2Mo10O40.nH2O/TiO2 was characterized using FTTR spectroscopy, X-Ray analysis, and acidity measurement. FTTR spectrum showed that all vibration of titanium and polyoxometalate were appeared in H5PV2Mo10O40.nH2O/TiO2 with decreasing crystallinity. The acidity of H5PV2Mo10O40.nH2O/TiO2 was higher than H5PV2Mo10O40.nH2O. Desulfurization of 4-methyl dibenzothiophene (4-MDBT) using H5PV2Mo10O40.nH2O/TiO2 as catalyst resulted conversion of 4-MDBT was 99% and higher than desulfurization using H5PV2Mo10O40.nH2O under mild conditions.

[Application of activated carbon from waste tea in desulfurization and denitrification].

PubMed

Song, Lei; Zhang, Bin; Deng, Wen

2014-10-01

The effects of pore structure, graphite and surface structure of waste tea activated carbon on its desulfurization and denitrification performance were investigated. The adsorption kinetics and adsorption process were also studied. The results showed that less graphitization, lower micropore size and more nitrogenous basic group of adsorbent enhanced its desulfurization ability. When well- developed mesopores were present in adsorbent, the NO removal efficiency was decreased, while more nitrogenous basic groups promoted the removal rate of NO. When SO2 and NO were removed together, competing adsorption occurred. After oxygen and steam were introduced to the flue gas, the removal efficiencies of SO2 and NO were increased. The adsorption of SO2 and NO onto waste tea activated carbon was physical adsorption without O2 and H2O, while the vapor promoted chemical adsorption of SO2 in the presence of water and oxygen. The adsorption process of the material can be well described by Bangham's kinetic equation, and the value of R2 was no less than 0.989. O2 and water vapor slowed the adsorption rates of SO2 and NO.

[Simultaneous desulfurization and denitrification by TiO2/ACF under different irradiation].

PubMed

Han, Jing; Zhao, Yi

2009-04-15

The supported TiO2 photocatalysts were prepared in laboratory, and the experiments of simultaneous desulfurization and denitrification were carried out by self-designed photocatalysis reactor. The optimal experimental conditions were achieved, and the efficiencies of simultaneous desulfurization and denitrification under two different light sources were compared. The results show that the oxygen content of flue gas, reaction temperature, flue gas humidity and irradiation intensity are most essential factors to photocatalysis. For TiO2/ACF, the removal efficiencies of 99.7% for SO2 and 64.3% for NO are obtained respectively at optimal experimental conditions under UV irradiation. For TiO2/ACF, the removal efficiencies of 97.5% for SO2 and 49.6% for NO are achieved respectively at optimal experimental conditions under the visible light irradiation. The results of five times parallel experiments indicate standard deviation S of parallel data is little. The mechanism of removal for SO2 and NO is proposed under two light sources by ion chromatography analysis of the absorption liquid.

[Investigation of bacterial diversity in the biological desulfurization reactor for treating high salinity wastewater by the 16S rDNA cloning method].

PubMed

Liu, Wei-Guo; Liang, Cun-Zhen; Yang, Jin-Sheng; Wang, Gui-Ping; Liu, Miao-Miao

2013-02-01

The bacterial diversity in the biological desulfurization reactor operated continuously for 1 year was studied by the 16S rDNA cloning and sequencing method. Forty clones were randomly selected and their partial 16S rDNA genes (ca. 1,400 bp) were sequenced and blasted. The results indicated that there were dominant bacterias in the biological desulfurization reactor, where 33 clones belonged to 3 different published phyla, while 1 clone belonged to unknown phylum. The dominant bacterial community in the system was Proteobacteria, which accounted for 85.3%. The bacterial community succession was as follows: the gamma-Proteobacteria(55.9%), beta-Proteobacteria(17.6%), Actinobacteridae (8.8%), delta-Proteobacteria (5.9%) , alpha-Proteobacteria(5.9%), and Sphingobacteria (2.9%). Halothiobacillus sp. ST15 and Thiobacillus sp. UAM-I were the major desulfurization strains.

Desulfurization of Hydrocarbon Fuels at Ambient Conditions Using Supported Silver Oxide-Titania Sorbents

DTIC Science & Technology

2010-12-13

required as a dopant in a two- component active metal matrix to generate surface defects. The use of high surface area supports has been demonstrated...B. S., Burton, J. F., Cullo, A. L. Supported cobalt sulfate desulfurization catalyst. US Patent No 74-483982 [110] Sivaraj, C., Contescu, C

Synthesis and characterization of porous metal oxides and desulfurization studies of sulfur containing compounds

NASA Astrophysics Data System (ADS)

Garces Trujillo, Hector Fabian

This thesis contains two parts: 1) synthesis and characterization of porous metal oxides that include zinc oxide and a porous mixed-valent manganese oxide with an amorphous structure (AMO) 2) the desulfurization studies for the removal of sulfur compounds. Zinc oxide with different nano-scale morphologies may result in various porosities with different adsorption capabilities. A tunable shape microwave synthesis of ZnO nano-spheres in a co-solvent mixture is presented. The ZnO nano-sphere material is investigated as a desulfurizing sorbent in a fixed bed reactor in the temperature range 200 to 400 °C and compared with ZnO nanorods and platelet-like morphologies. Fresh and sulfided materials were characterized by X-ray diffraction (XRD), BET specific surface area, pore volume, scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (SEM/EDX), Raman spectroscopy, and thermogravimetric analysis (TGA). The tunable shape microwave synthesis of ZnO presents a high sulfur sorption capacity at temperatures as low as 200 °C which accounts for a three and four fold enhancement over the other preparations presented in this work, and reached 76 % of the theoretical sulfur capacity (TSC) at 300 °C. Another ZnO material with a bimodal micro- and mesopore size distribution investigated as a desulfurizing sorbent presents a sorption capacity that reaches 87% of the theoretical value for desulfurization at 400 °C at breakthrough time. A deactivation model that considers the activity of the solid reactant was used to fit the experimental data. Good agreement between the experimental breakthrough curves and the model predictions are obtained. Manganese oxides are a type of metal oxide materials commonly used in catalytic applications. Little is known about the adsorption capabilities for the removal of sulfur compounds. One of these manganese oxides; amorphous manganese oxide (AMO) is highly promising material for low temperature sorption processes. Amorphous

Bubble-Free Propulsion of Ultrasmall Tubular Nanojets Powered by Biocatalytic Reactions.

PubMed

Ma, Xing; Hortelao, Ana C; Miguel-López, Albert; Sánchez, Samuel

2016-10-26

The motion of self-propelled tubular micro- and nanojets has so far been achieved by bubble propulsion, e.g., O 2 bubbles formed by catalytic decomposition of H 2 O 2 , which renders future biomedical applications inviable. An alternative self-propulsion mechanism for tubular engines on the nanometer scale is still missing. Here, we report the fabrication and characterization of bubble-free propelled tubular nanojets (as small as 220 nm diameter), powered by an enzyme-triggered biocatalytic reaction using urea as fuel. We studied the translational and rotational dynamics of the nanojets as functions of the length and location of the enzymes. Introducing tracer nanoparticles into the system, we demonstrated the presence of an internal flow that extends into the external fluid via the cavity opening, leading to the self-propulsion. One-dimensional nanosize, longitudinal self-propulsion, and biocompatibility make the tubular nanojets promising for future biomedical applications.

Biocatalytic, one-pot diterminal oxidation and esterification of n-alkanes for production of α,ω-diol and α,ω-dicarboxylic acid esters.

PubMed

van Nuland, Youri M; de Vogel, Fons A; Scott, Elinor L; Eggink, Gerrit; Weusthuis, Ruud A

2017-11-01

Direct and selective terminal oxidation of medium-chain n-alkanes is a major challenge in chemistry. Efforts to achieve this have so far resulted in low specificity and overoxidized products. Biocatalytic oxidation of medium-chain n-alkanes - with for example the alkane monooxygenase AlkB from P. putida GPo1- on the other hand is highly selective. However, it also results in overoxidation. Moreover, diterminal oxidation of medium-chain n-alkanes is inefficient. Hence, α,ω-bifunctional monomers are mostly produced from olefins using energy intensive, multi-step processes. By combining biocatalytic oxidation with esterification we drastically increased diterminal oxidation upto 92mol% and reduced overoxidation to 3% for n-hexane. This methodology allowed us to convert medium-chain n-alkanes into α,ω-diacetoxyalkanes and esterified α,ω-dicarboxylic acids. We achieved this in a one-pot reaction with resting-cell suspensions of genetically engineered Escherichia coli. The combination of terminal oxidation and esterification constitutes a versatile toolbox to produce α,ω-bifunctional monomers from n-alkanes. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Numerical simulation of flow in the wet scrubber for desulfurization

NASA Astrophysics Data System (ADS)

Novosád, Jan; Vít, Tomáš

2015-05-01

This article deals with numerical simulation of flow and chemical reactions in absorber for desulfurization of flue-gas. The objective of the work is the investigation of effect of different nozzles types and their placement in spray layers. These nozzles distribute lime suspension into flue gas stream. The research includes two types of nozzles and four different arrangements of nozzles and spray layers. Conclusion describes the effect of nozzle types and their arrangements on the suspension concentration in absorber.

Preparation of AAO-CeO2 nanotubes and their application in electrochemical oxidation desulfurization of diesel

NASA Astrophysics Data System (ADS)

Du, Xiaoqing; Yang, Yumeng; Yi, Chenxi; Chen, Yu; Cai, Chao; Zhang, Zhao

2017-02-01

The coaxial arrays of AAO-CeO2 NTs have been successfully galvanostatically deposited on an anode, characterized and adopted as a catalyst for removing organic sulfurs from diesel. The influence of the main electrochemical oxidation factors on the efficiency of desulfurization have also been investigated. The results show that the fabrication process of AAO-CeO2 NTs is accompanied by the formation of a new phase, namely Al3Ce, and the main oxidation products of the diesel are soluble inorganic sulphides, especially Ce2(SO4)3. When compared with dibenzothiophene and 4, 6-dimethyldibenzothiophene, benzothiophene is much more easily removed, with a removal efficiency that reaches 87.2%. Finally, a possible electrochemical oxidation desulfurization pathway for diesel is proposed.

Flue gas desulfurization gypsum: Its effectiveness as an alternative bedding material for broiler production

USDA-ARS?s Scientific Manuscript database

Flue gas desulfurization gypsum (FGDG) may be a viable low-cost alternative bedding material for broiler production. In order to evaluate FGD gypsum’s viability, three consecutive trials were conducted to determine its influence on live performance (body weight, feed consumption, feed efficiency, an...

Desulfurization of benzonaphthothiophenes and dibenzothiophene with a Raney nickel catalyst and its relationship to the. pi. -electron density

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

Nagai, M.; Urimoto, H.; Uetake, K.

The hydrodesulfurization of heavy petroleum feedstocks and coal-derived liquids requires the conversion of high molecular weight compounds like dibenzothiophene and benzonaphthothiophenes. There are several studies in the literature which deal with the mechanism of the hydrodesulfurization of multi-ring thiophenic compounds on cobalt or nickel molybdenum catalysts at high pressure. However, there are only a few studies which relate the chemical reactivity of these compounds to their electronic structure. The reactivity of a multi-ring sulfur-containing compound is not determined solely by the size of the molecule. In addition, others studied the relationship between the first step in the hydrotreating reaction ofmore » benzonaphthothiophene and the Coulombic interaction term of the compounds using the CNDO/S method. Because there is competition between the different processes (hydrogenation and desulfurization) during reaction, it is difficult to understand the relationship between desulfurization and the electronic properties of the compounds under reaction conditions. The calculation of electronic structures necessarily involves many sigma bonds of hydrogenated aromatic rings as well as many electrons of high molecular weight compounds. For this reason, it is best to select a catalyst and reaction conditions under which desulfurization takes place without hydrogenation.« less

Highly stable and regenerable Mn-based/SBA-15 sorbents for desulfurization of hot coal gas.

PubMed

Zhang, F M; Liu, B S; Zhang, Y; Guo, Y H; Wan, Z Y; Subhan, Fazle

2012-09-30

A series of mesoporous xCuyMn/SBA-15 sorbents with different Cu/Mn atomic ratios were prepared by wet impregnation method and their desulfurization performance in hot coal gas was investigated in a fixed-bed quartz reactor in the range of 700-850°C. The successive nine desulfurization-regeneration cycles at 800°C revealed that 1Cu9Mn/SBA-15 presented high performance with durable regeneration ability due to the high dispersion of Mn(2)O(3) particles incorporated with a certain amount of copper oxides. The breakthrough sulfur capacity of 1Cu9Mn/SBA-15 observed 800°C is 13.8 g S/100g sorbents, which is remarkably higher than these of 40 wt%LaFeO(3)/SBA-15 (4.8 g S/100g sorbents) and 50 wt%LaFe(2)O(x)/MCM-41 (5.58 g S/100g sorbents) used only at 500-550°C. This suggested that the loading of Mn(2)O(3) active species with high thermal stability to SBA-15 support significantly increased sulfur capacity at relatively higher sulfidation temperature. The fresh and used xCuyMn/SBA-15 sorbents were characterized by means of BET, XRD, XPS, XAES, TG/DSC and HRTEM techniques, confirmed that the structure of the sorbents remained intact before and after hot coal gas desulfurization. Copyright © 2012 Elsevier B.V. All rights reserved.

Flue gas desulfurization method and apparatus

DOEpatents

Madden, Deborah A.; Farthing, George A.

1998-08-18

A combined furnace limestone injection and dry scrubber flue gas desulfurization (FGD) system collects solids from the flue gas stream in first particulate collection device located downstream of an outlet of a convection pass of the furnace and upstream of the dry scrubber. The collected solids are diverted to the dry scrubber feed slurry preparation system to increase sulfur oxide species removal efficiency and sorbent utilization. The level of lime in the feed slurry provided to the dry scrubber is thus increased, which enhances removal of sulfur oxide species in the dry scrubber. The decreased particulate loading to the dry scrubber helps maintain a desired degree of free moisture in the flue gas stream entering the dry scrubber, which enhances sulfur oxide species removal both in the dry scrubber and downstream particulate collector, normally a baghouse.

Flue gas desulfurization method and apparatus

DOEpatents

Madden, D.A.; Farthing, G.A.

1998-08-18

A combined furnace limestone injection and dry scrubber flue gas desulfurization (FGD) system collects solids from the flue gas stream in first particulate collection device located downstream of an outlet of a convection pass of the furnace and upstream of the dry scrubber. The collected solids are diverted to the dry scrubber feed slurry preparation system to increase sulfur oxide species removal efficiency and sorbent utilization. The level of lime in the feed slurry provided to the dry scrubber is thus increased, which enhances removal of sulfur oxide species in the dry scrubber. The decreased particulate loading to the dry scrubber helps maintain a desired degree of free moisture in the flue gas stream entering the dry scrubber, which enhances sulfur oxide species removal both in the dry scrubber and downstream particulate collector, normally a baghouse. 5 figs.

Flue gas desulfurization method and apparatus

DOEpatents

Madden, Deborah A.; Farthing, George A.

1998-09-29

A combined furnace limestone injection and dry scrubber flue gas desulfurization (FGD) system collects solids from the flue gas stream in first particulate collection device located downstream of an outlet of a convection pass of the furnace and upstream of the dry scrubber. The collected solids are diverted to the dry scrubber feed slurry preparation system to increase sulfur oxide species removal efficiency and sorbent utilization. The level of lime in the feed slurry provided to the dry scrubber is thus increased, which enhances removal of sulfur oxide species in the dry scrubber. The decreased particulate loading to the dry scrubber helps maintain a desired degree of free moisture in the flue gas stream entering the dry scrubber, which enhances sulfur oxide species removal both in the dry scrubber and downstream particulate collector, normally a baghouse.

Flue gas desulfurization method and apparatus

DOEpatents

Madden, D.A.; Farthing, G.A.

1998-09-29

A combined furnace limestone injection and dry scrubber flue gas desulfurization (FGD) system collects solids from the flue gas stream in first particulate collection device located downstream of an outlet of a convection pass of the furnace and upstream of the dry scrubber. The collected solids are diverted to the dry scrubber feed slurry preparation system to increase sulfur oxide species removal efficiency and sorbent utilization. The level of lime in the feed slurry provided to the dry scrubber is thus increased, which enhances removal of sulfur oxide species in the dry scrubber. The decreased particulate loading to the dry scrubber helps maintain a desired degree of free moisture in the flue gas stream entering the dry scrubber, which enhances sulfur oxide species removal both in the dry scrubber and downstream particulate collector, normally a baghouse. 5 figs.

Enhancing the biocatalytic manufacture of the key intermediate of atorvastatin by focused directed evolution of halohydrin dehalogenase.

PubMed

Luo, Yu; Chen, Yangzi; Ma, Hongmin; Tian, ZhenHua; Zhang, Yeqi; Zhang, Jian

2017-02-06

Halohydrin dehalogenases (HHDHs) are biocatalytically interesting enzymes due to their ability to form C-C, C-N, C-O, and C-S bonds. One of most important application of HHDH was the protein engineering of HheC (halohydrin dehalogenase from Agrobacterium radiobacter AD1) for the industrial manufacturing of ethyl (R)-4-cyano-3-hydroxybutanoate (HN), a key chiral synthon of a cholesterol-lowering drug of atorvastatin. During our development of an alternative, more efficient and economic route for chemo-enzymatic preparation of the intermediate of atorvastatin, we found that the HheC2360 previously reported for HN manufacture, had insufficient activity for the cyanolysis production of tert-butyl (3 R,5 S)-6-cyano-3,5-dihydroxyhexanoate (A7). Herein, we present the focused directed evolution of HheC2360 with higher activity and enhanced biocatalytic performance using active site mutagenesis. Through docking of the product, A7, into the crystal structure of HheC2360, 6 residues was selected for combined active sites testing (CASTing). After library screening, the variant V84G/W86F was identified to have a 15- fold increase in activity. Time course analysis of the cyanolysis reaction catalyzed by this variant, showed 2- fold increase in space time productivity compared with HheC2360. These results demonstrate the applicability of the variant V84G/W86F as a biocatalyst for the efficient and practical production of atorvastatin intermediate.

Desulfurization apparatus and method

DOEpatents

Rong, Charles; Jiang, Rongzhong; Chu, Deryn

2013-06-18

A method and system for desulfurization comprising first and second metal oxides; a walled enclosure having an inlet and an exhaust for the passage of gas to be treated; the first and second metal oxide being combinable with hydrogen sulfide to produce a reaction comprising a sulfide and water; the first metal oxide forming a first layer and the second metal oxide forming a second layer within the walled surroundings; the first and second layers being positioned so the first layer removes the bulk amount of the hydrogen sulfide from the treated gas prior to passage through the second layer, and the second layer removes substantially all of the remaining hydrogen sulfide from the treated gas; the first metal oxide producing a stoichiometrical capacity in excess of 500 mg sulfur/gram; the second metal oxide reacts with the hydrogen sulfide more favorably but has a stoichometrical capacity which is less than the first reactant; whereby the optimal amount by weight of the first and second metal oxides is achieved by utilizing two to three units by weight of the first metal oxide for every unit of the second metal oxide.

Building carbon–carbon bonds using a biocatalytic methanol condensation cycle

PubMed Central

Bogorad, Igor W.; Chen, Chang-Ting; Theisen, Matthew K.; Wu, Tung-Yun; Schlenz, Alicia R.; Lam, Albert T.; Liao, James C.

2014-01-01

Methanol is an important intermediate in the utilization of natural gas for synthesizing other feedstock chemicals. Typically, chemical approaches for building C–C bonds from methanol require high temperature and pressure. Biological conversion of methanol to longer carbon chain compounds is feasible; however, the natural biological pathways for methanol utilization involve carbon dioxide loss or ATP expenditure. Here we demonstrated a biocatalytic pathway, termed the methanol condensation cycle (MCC), by combining the nonoxidative glycolysis with the ribulose monophosphate pathway to convert methanol to higher-chain alcohols or other acetyl-CoA derivatives using enzymatic reactions in a carbon-conserved and ATP-independent system. We investigated the robustness of MCC and identified operational regions. We confirmed that the pathway forms a catalytic cycle through 13C-carbon labeling. With a cell-free system, we demonstrated the conversion of methanol to ethanol or n-butanol. The high carbon efficiency and low operating temperature are attractive for transforming natural gas-derived methanol to longer-chain liquid fuels and other chemical derivatives. PMID:25355907

Ultrasound-assisted oxidative desulfurization and denitrogenation of liquid hydrocarbon fuels: A critical review.

PubMed

Ja'fari, Mahsa; Ebrahimi, Seyedeh Leila; Khosravi-Nikou, Mohammad Reza

2018-01-01

Nowadays, a continuously worldwide concern for development of process to produce ultra-low sulfur and nitrogen fuels have been emerged. Typical hydrodesulfurization and hydrodenitrogenation technology deals with important difficulties such as high pressure and temperature operating condition, failure to treat some recalcitrant compounds and limitations to meet the stringent environmental regulations. In contrary an advanced oxidation process that is ultrasound assisted oxidative desulfurization and denitrogenation satisfies latest environmental regulations in much milder conditions with more efficiency. The present work deals with a comprehensive review on findings and development in the ultrasound assisted oxidative desulfurization and denitrogenation (UAOD) during the last decades. The role of individual parameters namely temperature, residence time, ultrasound power and frequency, pH, initial concentration and types of sulfur and nitrogen compounds on the efficiency are described. What's more another treatment properties that is role of phase transfer agent (PTA) and solvents of extraction step, reaction kinetics, mechanism of the ultrasound, fuel properties and recovery in UAOD are reviewed. Finally, the required future works to mature this technology are suggested. Copyright © 2017 Elsevier B.V. All rights reserved.

THE EFFECT OF FLUE GAS DESULFURIZATION AVAILABILITY ON ELECTRIC UTILITIES. VOLUME II. TECHNICAL REPORT

EPA Science Inventory

The report gives results of an analysis of the effect of the availability of a flue gas desulfurization system on the ability of an individual power plant to generate electricity at its rated capacity. (The availability of anything is the fraction of time it is capable of service...

THE EFFECT OF FLUE GAS DESULFURIZATION AVAILABILITY ON ELECTRIC UTILITIES. VOLUME I. EXECUTIVE SUMMARY

EPA Science Inventory

The report gives results of an analysis of the effect of the availability of a flue gas desulfurization system on the ability of an individual power plant to generate electricity at its rated capacity. (The availability of anything is the fraction of time it is capable of service...

Influence of Fe loadings on desulfurization performance of activated carbon treated by nitric acid.

PubMed

Guo, Jia-Xiu; Shu, Song; Liu, Xiao-Li; Wang, Xue-Jiao; Yin, Hua-Qiang; Chu, Ying-Hao

2017-02-01

A series of Fe supported on activated carbon treated by nitric acid are prepared by incipient wetness impregnation with ultrasonic assistance and characterized by N 2 adsorption-desorption, X-ray diffraction, Fourier transform infrared spectrum and X-ray photoelectron spectroscopy. It has shown that Fe loadings significantly influence the desulfurization activity. Fe/NAC5 exhibits an excellent removal ability of SO 2 , corresponding to breakthrough sulfur capacity of 323 mg/g. With the increasing Fe loadings, the generated Fe 3 O 4 and Fe 2 SiO 4 increase, but Fe 2 (SO 4 ) 3 is observed after desulfurization. Fe/NAC1 has a Brunauer-Emmett-Teller (BET) surface area of 925 m 2 /g with micropore surface area of 843 m 2 /g and total pore volume of 0.562 cm 3 /g including a micropore volume of 0.300 cm 3 /g. With the increasing Fe loadings, BET surface area and micropore volume decrease, and those of Fe/NAC10 decrease to 706 m 2 /g and 0.249 cm 3 /g. The Fe loadings influence the pore-size distribution, and SO 2 adsorption mainly reacts in micropores at about 0.70 nm. C=O and C-O are observed for all samples before SO 2 removal. After desulfurization, the C-O stretching is still detected, but the C=O stretching vibration of carbonyl groups disappears. The stretching of S-O or S=O in sulfate is observed at 592 cm -1 for the used sample, proving that the existence of [Formula: see text].

Development of corrosion resistant heat exchangers for flue gas desulfurization

NASA Astrophysics Data System (ADS)

Ernst, E.; Lorentz, R.

1984-12-01

A glass lining as protection against corrosion in flue gas desulfurization plants was developed. Glasses were evaluated under corrosive attack of fluoride-containing acids. The corrosion properties of one-layer and two-layer glass enamels are optimized. Two-layer systems always show better resistance and longer life. The optimized glass linings were tested in a power plant. Manufacturing principles for glass-lined heat exchanger elements are derived. The optimized glasses may be used as protective lining design for heat exchangers or parts of them.

Silver nanocrystal-decorated polyoxometalate single-walled nanotubes as nanoreactors for desulfurization catalysis at room temperature.

PubMed

Zhang, Hao; Xu, Xiaobin; Lin, Haifeng; Ud Din, Muhammad Aizaz; Wang, Haiqing; Wang, Xun

2017-09-14

Ultrathin nanocrystals generally provide a remarkable catalytic performance due to their high specific surface area and exposure of certain active sites. However, deactivation caused by growth and gathering limits the catalytic application of ultrathin nanocrystals. Here we report Ag nanocrystal-decorated polyoxometalate (Ag-POM) single-walled nanotubes assembled via a concise, surfactant-free soaking method as a new kind of well-defined core-sheath nanoreactor. The diameter of Ag nanocrystals inside polyoxometalate nanotubes can be controlled via simply adjusting the reactant concentration. Ag-POM provided outstanding oxidative desulfurization (ODS) catalytic performance for aromatic sulfocompounds at room temperature. It was suggested that Ag nanocrystals decorated on the inner surface played a key role in adjusting the electronic distribution and enhancing the catalytic activity. The as-prepared Ag-POM nanotubes are promising candidate catalysts with enhanced performance for practical catalytic applications in the gasoline desulfurization industry.

Applying ACF to Desulfurization Process from Flue Gas

NASA Astrophysics Data System (ADS)

Liu, Yi; Zhang, Zhigang; Tang, Qiang; Cao, Zidong

2004-08-01

Inasmuch as the status of environmental pollution caused by SO2 is more and more serious and the policy of environmental protection is executed more and more strictly, desulfurization from flue gas (FGD) is introduced to a wide-spread field of national economy. By a comparison with lime-limestone method, the application of adsorption method in FGD is more effective in desulfurization and more adapted to the situation of our country in respect of its more valuable byproduct. However, the technique of adsorption method is limited by the large amount of adsorbent used. In this paper, activated carbon fiber (ACF) is proposed as a new type of adsorbent to apply in FGD. A series of experiments have been made in order to compare the performances between ACF and granular activated carbon (GAC) which has been mostly used. Experiments show that under the same working conditions ACF's adsorption capacity is 16.6 times as high as that of GAC, mass loss rate is 1/12 of GAC's, desorption efficiency of ACF can reach 99.9%. The theory of micropore adsorption dynamics is adopted to analyze the characteristics of both adsorbents. It is indicated that adsorbability and perfectibility of desorption are tightly related to the distribution of pores and the surface micromechanism of adsorbent surface. The accessibility of pores for specified adsorptive and the effects of capillary condensation are crucial factors to influence the process of FGD. According to the research of different adsorbents, conclusion can be drawn that ACF is a kind of good material with a strong selectivity for SO2. Compared with the traditional methods of FGD, the use of ACF can greatly economize the consumption of adsorbent and obviously reduce the introduction of new adsorbent, and at the same time keep down the equipment investment and operating cost.

Developing clean fuels: Novel techniques for desulfurization

NASA Astrophysics Data System (ADS)

Nehlsen, James P.

The removal of sulfur compounds from petroleum is crucial to producing clean burning fuels. Sulfur compounds poison emission control catalysts and are the source of acid rain. New federal regulations require the removal of sulfur in both gasoline and diesel to very low levels, forcing existing technologies to be pushed into inefficient operating regimes. New technology is required to efficiently produce low sulfur fuels. Two processes for the removal of sulfur compounds from petroleum have been developed: the removal of alkanethiols by heterogeneous reaction with metal oxides; and oxidative desulfurization of sulfides and thiophene by reaction with sulfuric acid. Alkanethiols, common in hydrotreated gasoline, can be selectively removed and recovered from a hydrocarbon stream by heterogeneous reaction with oxides of Pb, Hg(II), and Ba. The choice of reactive metal oxides may be predicted from simple thermodynamic considerations. The reaction is found to be autocatalytic, first order in water, and zero order in thiol in the presence of excess oxide. The thiols are recovered by reactive extraction with dilute oxidizing acid. The potential for using polymer membrane hydrogenation reactors (PEMHRs) to perform hydrogenation reactions such as hydrodesulfurization is explored by hydrogenating ketones and olefins over Pt and Au group metals. The dependence of reaction rate on current density suggests that the first hydrogen addition to the olefin is the rate limiting step, rather than the adsorption of hydrogen, for all of the metals tested. PEMHRs proved unsuccessful in hydrogenating sulfur compounds to perform HDS. For the removal of sulfides, a two-phase reactor is used in which concentrated sulfuric acid oxidizes aromatic and aliphatic sulfides present in a hydrocarbon solvent, generating sulfoxides and other sulfonated species. The polar oxidized species are extracted into the acid phase, effectively desulfurizing the hydrocarbon. A reaction scheme is proposed for this

Method for desulfurization of coal

DOEpatents

Kelland, D.R.

1987-07-07

A process and apparatus are disclosed for desulfurizing coal which removes sulfur in the inorganic and organic form by preferentially heating the inorganic iron sulfides in coal in a flowing gas to convert some of the inorganic iron sulfides from a pyrite form FeS[sub 2] to a troilite FeS form or a pyrrhotite form Fe[sub 1[minus]x]S and release some of the sulfur as a gaseous compound. The troilite and pyrrhotite forms are convenient catalyst for removing the organic sulfur in the next step, which is to react the coal with chemical agents such as alcohol, thus removing the organic sulfur as a liquid or a gas such as H[sub 2]S. The remaining inorganic sulfur is left in the predominantly higher magnetic form of pyrrhotite and is then removed by magnetic separation techniques. Optionally, an organic flocculant may be added after the organic sulfur has been removed and before magnetic separation. The flocculant attaches non-pyrite minerals with the pyrrhotite for removal by magnetic separation to reduce the ash-forming contents. 2 figs.

Method for desulfurization of coal

DOEpatents

Kelland, David R.

1987-01-01

A process and apparatus for desulfurizing coal which removes sulfur in the inorganic and organic form by preferentially heating the inorganic iron sulfides in coal in a flowing gas to convert some of the inorganic iron sulfides from a pyrite form FeS.sub.2 to a troilite FeS form or a pyrrhotite form Fe.sub.1-x S and release some of the sulfur as a gaseous compound. The troilite and pyrrhotite forms are convenient catalyst for removing the organic sulfur in the next step, which is to react the coal with chemical agents such as alcohol, thus removing the organic sulfur as a liquid or a gas such as H.sub.2 S. The remaining inorganic sulfur is left in the predominantly higher magnetic form of pyrrhotite and is then removed by magnetic separation techniques. Optionally, an organic flocculant may be added after the organic sulfur has been removed and before magnetic separation. The flocculant attaches non-pyrite minerals with the pyrrhotite for removal by magnetic separation to reduce the ash-forming contents.

DEVELOPMENT OF INFRARED METHODS FOR CHARACTERIZATION OF INORGANIC SULFUR SPECIES RELATED TO INJECTION DESULFURIZATION PROCESSES

EPA Science Inventory

Current methods designed to control and reduce the amount of sulfur dioxide emitted into the atmosphere from coal-fired power plants and factories rely upon the reaction between SO2 and alkaline earth compounds and are called flue gas desulfurization (FGD) processes. Of these met...

Sugar analog synthesis by in vitro biocatalytic cascade: A comparison of alternative enzyme complements for dihydroxyacetone phosphate production as a precursor to rare chiral sugar synthesis.

PubMed

Hartley, Carol J; French, Nigel G; Scoble, Judith A; Williams, Charlotte C; Churches, Quentin I; Frazer, Andrew R; Taylor, Matthew C; Coia, Greg; Simpson, Gregory; Turner, Nicholas J; Scott, Colin

2017-01-01

Carbon-carbon bond formation is one of the most challenging reactions in synthetic organic chemistry, and aldol reactions catalysed by dihydroxyacetone phosphate-dependent aldolases provide a powerful biocatalytic tool for combining C-C bond formation with the generation of two new stereo-centres, with access to all four possible stereoisomers of a compound. Dihydroxyacetone phosphate (DHAP) is unstable so the provision of DHAP for DHAP-dependent aldolases in biocatalytic processes remains complicated. Our research has investigated the efficiency of several different enzymatic cascades for the conversion of glycerol to DHAP, including characterising new candidate enzymes for some of the reaction steps. The most efficient cascade for DHAP production, comprising a one-pot four-enzyme reaction with glycerol kinase, acetate kinase, glycerophosphate oxidase and catalase, was coupled with a DHAP-dependent fructose-1,6-biphosphate aldolase enzyme to demonstrate the production of several rare chiral sugars. The limitation of batch biocatalysis for these reactions and the potential for improvement using kinetic modelling and flow biocatalysis systems is discussed.

Methods, systems, and devices for deep desulfurization of fuel gases

DOEpatents

Li, Liyu [Richland, WA; King, David L [Richland, WA; Liu, Jun [Richland, WA; Huo, Qisheng [Richland, WA

2012-04-17

A highly effective and regenerable method, system and device that enables the desulfurization of warm fuel gases by passing these warm gasses over metal-based sorbents arranged in a mesoporous substrate. This technology will protect Fischer-Tropsch synthesis catalysts and other sulfur sensitive catalysts, without drastic cooling of the fuel gases. This invention can be utilized in a process either alone or alongside other separation processes, and allows the total sulfur in such a gas to be reduced to less than 500 ppb and in some instances as low as 50 ppb.

PROCEEDINGS: SYMPOSIUM ON FLUE GAS DESULFURIZATION HELD AT LAS VEGAS, NEVADA, MARCH 1979; VOLUME II

EPA Science Inventory

The publication, in two volumes, contains the text of all papers presented at EPA's fifth flue gas desulfurization (FGD) symposium, March 5-8, 1979, at Las Vegas, Nevada. A partial listing of papers in Volume 2 includes the following: Basin Electric's involvement with dry flue ga...

COMPARISON OF WEST GERMAN AND U.S. FLUE GAS DESULFURIZATION AND SELECTIVE CATALYTIC REDUCTION COSTS

EPA Science Inventory

The report documents a comparison of the actual cost retrofitting flue gas desulfurization (FGD) and selective catalytic reduction (SCR) on Federal Republic of German (FRG) boilers to cost estimating procedures used in the U.S. to estimate the retrofit of these controls on U.S. b...

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.

The Natural History of Biocatalytic Mechanisms

PubMed Central

Nath, Neetika; Mitchell, John B. O.; Caetano-Anollés, Gustavo

2014-01-01

Phylogenomic analysis of the occurrence and abundance of protein domains in proteomes has recently showed that the α/β architecture is probably the oldest fold design. This holds important implications for the origins of biochemistry. Here we explore structure-function relationships addressing the use of chemical mechanisms by ancestral enzymes. We test the hypothesis that the oldest folds used the most mechanisms. We start by tracing biocatalytic mechanisms operating in metabolic enzymes along a phylogenetic timeline of the first appearance of homologous superfamilies of protein domain structures from CATH. A total of 335 enzyme reactions were retrieved from MACiE and were mapped over fold age. We define a mechanistic step type as one of the 51 mechanistic annotations given in MACiE, and each step of each of the 335 mechanisms was described using one or more of these annotations. We find that the first two folds, the P-loop containing nucleotide triphosphate hydrolase and the NAD(P)-binding Rossmann-like homologous superfamilies, were α/β architectures responsible for introducing 35% (18/51) of the known mechanistic step types. We find that these two oldest structures in the phylogenomic analysis of protein domains introduced many mechanistic step types that were later combinatorially spread in catalytic history. The most common mechanistic step types included fundamental building blocks of enzyme chemistry: “Proton transfer,” “Bimolecular nucleophilic addition,” “Bimolecular nucleophilic substitution,” and “Unimolecular elimination by the conjugate base.” They were associated with the most ancestral fold structure typical of P-loop containing nucleotide triphosphate hydrolases. Over half of the mechanistic step types were introduced in the evolutionary timeline before the appearance of structures specific to diversified organisms, during a period of architectural diversification. The other half unfolded gradually after organismal

The natural history of biocatalytic mechanisms.

PubMed

Nath, Neetika; Mitchell, John B O; Caetano-Anollés, Gustavo

2014-05-01

Phylogenomic analysis of the occurrence and abundance of protein domains in proteomes has recently showed that the α/β architecture is probably the oldest fold design. This holds important implications for the origins of biochemistry. Here we explore structure-function relationships addressing the use of chemical mechanisms by ancestral enzymes. We test the hypothesis that the oldest folds used the most mechanisms. We start by tracing biocatalytic mechanisms operating in metabolic enzymes along a phylogenetic timeline of the first appearance of homologous superfamilies of protein domain structures from CATH. A total of 335 enzyme reactions were retrieved from MACiE and were mapped over fold age. We define a mechanistic step type as one of the 51 mechanistic annotations given in MACiE, and each step of each of the 335 mechanisms was described using one or more of these annotations. We find that the first two folds, the P-loop containing nucleotide triphosphate hydrolase and the NAD(P)-binding Rossmann-like homologous superfamilies, were α/β architectures responsible for introducing 35% (18/51) of the known mechanistic step types. We find that these two oldest structures in the phylogenomic analysis of protein domains introduced many mechanistic step types that were later combinatorially spread in catalytic history. The most common mechanistic step types included fundamental building blocks of enzyme chemistry: "Proton transfer," "Bimolecular nucleophilic addition," "Bimolecular nucleophilic substitution," and "Unimolecular elimination by the conjugate base." They were associated with the most ancestral fold structure typical of P-loop containing nucleotide triphosphate hydrolases. Over half of the mechanistic step types were introduced in the evolutionary timeline before the appearance of structures specific to diversified organisms, during a period of architectural diversification. The other half unfolded gradually after organismal diversification and during a

Use Of limestone resources in flue-gas desulfurization power plants in the Ohio River Valley

USGS Publications Warehouse

Foose, M.P.; Barsotti, A.F.

1999-01-01

In 1994, more than 41 of the approximately 160 coal-fired, electrical- power plants within the six-state Ohio River Valley region used flue-gas desulfurization (FGD) units to desulfurize their emissions, an approximately 100% increase over the number of plants using FGD units in 1989. This increase represents a trend that may continue with greater efforts to meet Federal Clean Air Act standards. Abundant limestone resources exist in the Ohio River Valley and are accessed by approximately 975 quarries. However, only 35 of these are believed to have supplied limestone for FGD electrical generating facilities. The locations of these limestone suppliers do not show a simple spatial correlation with FGD facilities, and the closest quarries are not being used in most cases. Thus, reduction in transportation costs may be possible in some cases. Most waste generated by FGD electrical-generating plants is not recycled. However, many FGD sites are relatively close to gypsum wallboard producers that may be able to process some of their waste.

Deep Desulfurization of Extensively Hydrodesulfurized Middle Distillate Oil by Rhodococcus sp. Strain ECRD-1

PubMed Central

Grossman, M. J.; Lee, M. K.; Prince, R. C.; Minak-Bernero, V.; George, G. N.; Pickering, I. J.

2001-01-01

Dibenzothiophene (DBT), and in particular substituted DBTs, are resistant to hydrodesulfurization (HDS) and can persist in fuels even after aggressive HDS treatment. Treatment by Rhodococcus sp. strain ECRD-1 of a middle distillate oil whose sulfur content was virtually all substituted DBTs produced extensive desulfurization and a sulfur level of 56 ppm. PMID:11282654

Desulfurization of Cysteine-Containing Peptides Resulting from Sample Preparation for Protein Characterization by MS

PubMed Central

Wang, Zhouxi; Rejtar, Tomas; Zhou, Zhaohui Sunny; Karger, Barry L.

2010-01-01

In this paper, we have examined two cysteine modifications resulting from sample preparation for protein characterization by MS: (1) a previously observed conversion of cysteine to dehydroalanine, now found in the case of disulfide mapping and (2) a novel modification corresponding to conversion of cysteine to alanine. Using model peptides, the conversion of cysteine to dehydroalanine via β-elimination of a disulfide bond was seen to result from the conditions of typical tryptic digestion (37 °C, pH 7.0– 9.0) without disulfide reduction and alkylation.. Furthermore, the surprising conversion of cysteine to alanine was shown to occur by heating cysteine containing peptides in the presence of a phosphine (TCEP). The formation of alanine from cysteine, investigated by performing experiments in H2O or D2O, suggested a radical-based desulfurization mechanism unrelated to β-elimination. Importantly, an understanding of the mechanism and conditions favorable for cysteine desulfurization provides insight for the establishment of improved sample preparation procedures of protein analysis. PMID:20049891

Potential Agricultural Uses of Flue Gas Desulfurization Gypsum in the Northern Great Plains

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

DeSutter, T.M.; Cihacek, L.J.

2009-07-15

Flue gas desulfurization gypsum (FGDG) is a byproduct from the combustion of coal for electrical energy production. Currently, FGDG is being produced by 15 electrical generating stations in Alabama, Florida, Indiana, Iowa, Kentucky, Ohio, North Carolina, South Carolina, Tennessee, Texas, and Wisconsin. Much of this byproduct is used in the manufacturing of wallboard. The National Network for Use of FGDG in Agriculture was initiated to explore alternative uses of this byproduct. In the northern Great Plains (North Dakota, South Dakota, and Montana), FGDG has the potential to be used as a Ca or S fertilizer, as an acid soil ameliorant,more » and for reclaiming or mitigating sodium-affected soils. Greater than 1.4 million Mg of FGDG could initially be used in these states for these purposes. Flue gas desulfurization gypsum can be an agriculturally important resource for helping to increase the usefulness of problem soils and to increase crop and rangeland production. Conducting beneficial use audits would increase the public awareness of this product and help identify to coal combustion electrical generating stations the agriculturally beneficial outlets for this byproduct.« less

In-Situ Biocatalytic Production of Trehalose with Autoinduction Expression of Trehalose Synthase.

PubMed

Yan, Xincheng; Zhu, Liying; Yu, Yadong; Xu, Qing; Huang, He; Jiang, Ling

2018-02-14

We developed an in-situ biocatalytic process that couples autoinduction expression of trehalose synthase (TreS) and whole-cell catalysis for trehalose production. With lactose as the autoinducer, the activity of recombinant TreS in recombinant Escherichia coli was optimized through a visualization method, which resulted in a maximum value of 12 033 ± 730 U/mL in pH-stat fed-batch fermentation mode. Meanwhile, the permeability of the autoinduced E. coli increased significantly, which makes it possible to be directly used as a whole-cell biocatalyst for trehalose production, whereby the byproduct glucose can also act as an extra carbon source. In this case, the final yield of trehalose was improved to 90.5 ± 5.7% and remained as high as 83.2 ± 5.0% at the 10th batch, which is the highest value achieved using recombinant TreS. Finally, an integrated strategy for trehalose production was established, and its advantages compared to the traditional mode have been summarized.

Immobilized biocatalytic process development and potential application in membrane separation: a review.

PubMed

Chakraborty, Sudip; Rusli, Handajaya; Nath, Arijit; Sikder, Jaya; Bhattacharjee, Chiranjib; Curcio, Stefano; Drioli, Enrico

2016-01-01

Biocatalytic membrane reactors have been widely used in different industries including food, fine chemicals, biological, biomedical, pharmaceuticals, environmental treatment and so on. This article gives an overview of the different immobilized enzymatic processes and their advantages over the conventional chemical catalysts. The application of a membrane bioreactor (MBR) reduces the energy consumption, and system size, in line with process intensification. The performances of MBR are considerably influenced by substrate concentration, immobilized matrix material, types of immobilization and the type of reactor. Advantages of a membrane associated bioreactor over a free-enzyme biochemical reaction, and a packed bed reactor are, large surface area of immobilization matrix, reuse of enzymes, better product recovery along with heterogeneous reactions, and continuous operation of the reactor. The present research work highlights immobilization techniques, reactor setup, enzyme stability under immobilized conditions, the hydrodynamics of MBR, and its application, particularly, in the field of sugar, starch, drinks, milk, pharmaceutical industries and energy generation.

Library of Norcoclaurine Synthases and Their Immobilization for Biocatalytic Transformations.

PubMed

Lechner, Horst; Soriano, Pablo; Poschner, Roman; Hailes, Helen C; Ward, John M; Kroutil, Wolfgang

2018-03-01

Norcoclaurine synthases (NCS), catalyzing a Pictet-Spengler reaction in plants as one of the first enzymes in the biosynthetic benzylisoquinoline pathway, are investigated for biocatalytic transformations. The library of NCS available is extended by two novel NCSs from Argemone mexicana (AmNCS1, AmNCS2) and one new NCS from Corydalis saxicola (CsNCS); furthermore, it is shown that the NCS from Papaver bracteatum (PbNCS) is a highly productive catalyst leading to the isoquinoline product with up to >99% e.e. Under certain conditions lyophilized whole Escherichia coli cells containing the various overexpressed NCS turned out to be suitable catalysts. The reaction using dopamine as substrate bears several challenges such as the spontaneous non-stereoselective background reaction and side reactions. The PbNCS enzyme is successfully immobilized on various carriers whereby EziG3 proved to be the best suited for biotransformations. Dopamine showed limited stability in solution resulting in the coating of the catalyst over time, which could be solved by the addition of ascorbic acid (e.g., 1 mg ml -1 ) as antioxidant. © 2017 The Authors. Biotechnology Journal Published by Wiley-VCH Verlag GmbH &Co. KGaA.

o-Iodoxybenzoic acid mediated oxidative desulfurization initiated domino reactions for synthesis of azoles.

PubMed

Chaudhari, Pramod S; Pathare, Sagar P; Akamanchi, Krishnacharaya G

2012-04-20

A systematic exploration of thiophilic ability of o-iodoxybenzoic acid (IBX) for oxidative desulfurization to trigger domino reactions leading to new methodologies for synthesis of different azoles is described. A variety of highly substituted oxadiazoles, thiadiazoles, triazoles, and tetrazoles have been successfully synthesized in good to excellent yields, starting from readily accessible thiosemicarbazides, bis-diarylthiourea, 1,3-disubtituted thiourea, and thioamides. © 2012 American Chemical Society

Low temperature oxidative desulfurization with hierarchically mesoporous titaniumsilicate Ti-SBA-2 single crystals.

PubMed

Shi, Chengxiang; Wang, Wenxuan; Liu, Ni; Xu, Xueyan; Wang, Danhong; Zhang, Minghui; Sun, Pingchuan; Chen, Tiehong

2015-07-21

Hierarchically porous Ti-SBA-2 with high framework Ti content (up to 5 wt%) was firstly synthesized by employing organic mesomorphous complexes of a cationic surfactant (CTAB) and an anionic polyelectrolyte (PAA) as templates. The material exhibited excellent performance in oxidative desulfurization of diesel fuel at low temperature (40 °C or 25 °C) due to the unique hierarchically porous structure and high framework Ti content.

A continuous system for biocatalytic hydrogenation of CO2 to formate.

PubMed

Mourato, Cláudia; Martins, Mónica; da Silva, Sofia M; Pereira, Inês A C

2017-07-01

In this work a novel bioprocess for hydrogenation of CO 2 to formate was developed, using whole cell catalysis by a sulfate-reducing bacterium. Three Desulfovibrio species were tested (D. vulgaris Hildenborough, D. alaskensis G20, and D. desulfuricans ATCC 27774), of which D. desulfuricans showed the highest activity, producing 12mM of formate in batch, with a production rate of 0.09mMh -1 . Gene expression analysis indicated that among the three formate dehydrogenases and five hydrogenases, the cytoplasmic FdhAB and the periplasmic [FeFe] HydAB are the main enzymes expressed in D. desulfuricans in these conditions. The new bioprocess for continuous formate production by D. desulfuricans had a maximum specific formate production rate of 14mMg dcw -1 h -1 , and more than 45mM of formate were obtained with a production rate of 0.40mMh -1 . This is the first report of a continuous process for biocatalytic formate production. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

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

Borole, Abhijeet P

2007-01-01

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

Multiphase Modeling of Bottom-Stirred Ladle for Prediction of Slag-Steel Interface and Estimation of Desulfurization Behavior

NASA Astrophysics Data System (ADS)

Singh, Umesh; Anapagaddi, Ravikiran; Mangal, Saurabh; Padmanabhan, Kuppuswamy Anantha; Singh, Amarendra Kumar

2016-06-01

Ladle furnace is a key unit in which various phenomena such as deoxidation, desulfurization, inclusion removal, and homogenization of alloy composition and temperature take place. Therefore, the processes present in the ladle play an important role in determining the quality of steel. Prediction of flow behavior of the phases present in the ladle furnace is needed to understand the phenomena that take place there and accordingly control the process parameters. In this study, first a mathematical model is developed to analyze the transient three-phase flow present. Argon gas bottom-stirred ladle with off-centered plugs has been used in this study. Volume of fluid method is used in a computational fluid dynamics (CFD) model to capture the behavior of slag, steel, and argon interfaces. The results are validated with data from literature. Eye opening and slag-steel interfacial area are calculated for different operating conditions and are compared with experimental and simulated results cited in literature. Desulfurization rate is then predicted using chemical kinetic equations, interfacial area, calculated from CFD model, and thermodynamic data, obtained from the Thermo-Calc software. Using the model, it is demonstrated that the double plug purging is more suitable than the single plug purging for the same level of total flow. The advantage is more distinct at higher flow rates as it leads higher interfacial area, needed for desulfurization and smaller eye openings (lower oxygen/nitrogen pickup).

Comparison on surface properties and desulfurization of MnO2 and pyrolusite blended activated carbon by steam activation.

PubMed

Zhang, Guochen; Zhao, Xin; Ning, Ping; Yang, Danni; Jiang, Xia; Jiang, Wenju

2018-04-18

In this study, MnO 2 and pyrolusite were used as the catalysts to prepare modified activated carbon, i.e., AC-Mn and AC-P, respectively, from coals by blending method and steam activation. The BET results indicated that the AC-P had higher surface areas and micropore volumes than the AC-Mn with the same blending ratio. The relative contents of basic functional groups (i.e. C = O, π-π*) on AC-P were slightly lower than those on AC-Mn, while both contained the same main metal species, i.e. MnO. The desulfurization results showed that with 3 wt% of blending ratio, AC-Mn3 and AC-P3 had higher sulfur capacities at 220 and 205 mg/g, respectively, which were much higher than blank one (149.6 mg/g). Moreover, the AC-P had relatively higher sulfur capacity than the AC-Mn with the same contents of Mn, which might be attributed to the existence of other metals in pyrolusite. After desulfurization process, MnO were gradually transferred into MnSO 4 , and the relative contents of basic functional groups decreased evidently for both AC-Mn3 and AC-P3. The results demonstrated that pyrolusite could be one good alternative of MnO 2 to prepare modified activated carbon for desulfurization. Implication statement MnO 2 and pyrolusite were used as the additives to prepare the modified activated carbon from coals by blending method and steam activation, i.e., AC-Mn and AC-P, respectively. The AC-P had higher surface areas and micropore volumes than the AC-Mn with the same blending ratio. The AC-Mn and AC-P had higher sulfur capacities than blank one. Moreover, the AC-P had relatively higher sulfur capacity than the AC-Mn with the same contents of Mn. The results demonstrated that pyrolusite could be one good alternative of MnO 2 to prepare modified activated carbon for desulfurization.

Substrate Preferences in Biodesulfurization of Diesel Range Fuels by Rhodococcus sp. Strain ECRD-1

PubMed Central

Prince, Roger C.; Grossman, Matthew J.

2003-01-01

The range of sulfur compounds in fuel oil and the substrate range and preference of the biocatalytic system determine the maximum extent to which sulfur can be removed by biodesulfurization. We show that the biodesulfurization apparatus in Rhodococcus sp. strain ECRD-1 is able to attack all isomers of dibenzothiophene including those with at least four pendant carbons, with a slight preference for those substituted in the α-position. With somewhat less avidity, this apparatus is also able to attack substituted benzothiophenes with between two and seven pendant carbons. Some compounds containing sulfidic sulfur are also susceptible to desulfurization, although we have not yet been able to determine their molecular identities. PMID:14532032

Sulfur-Specific Microbial Desulfurization of Sterically Hindered Analogs of Dibenzothiophene

PubMed Central

Lee, M. K.; Senius, J. D.; Grossman, M. J.

1995-01-01

Dibenzothiophenes (DBTs) bearing alkyl substitutions adjacent to the sulfur atom, such as 4,6-diethyldibenzothiophene (4,6-DEDBT), are referred to as sterically hindered with regard to access to the sulfur moiety. By using enrichment cultures with 4,6-DEDBT as the sole sulfur source, bacterial isolates which selectively remove sulfur from sterically hindered DBTs were obtained. The isolates were tentatively identified as Arthrobacter species. 4,6-DEDBT sulfone was shown to be an intermediate in the 4,6-DEDBT desulfurization pathway, and 2-hydroxy-3,3(prm1)-diethylbiphenyl (HDEBP) was identified as the sulfur-free end product. PMID:16535189

Impact of Leaching Conditions on Constituents Release from Flue Gas Desulfurization Gypsum (FGDG) and FGDG-Soil Mixture

EPA Science Inventory

The interest in using Flue Gas Desulfurization Gypsum(FGDG) has increased recently. This study evaluates the leaching characteristics of trace elements in "modern" FGDG (produced after fly ash removal) and FGDG-mixed soil (SF) under different environmental conditions using rece...

Desulfurization of 2-thiouracil nucleosides: conformational studies of 4-pyrimidinone nucleosides.

PubMed

Kraszewska, Karina; Kaczyńska, Iwona; Jankowski, Stefan; Karolak-Wojciechowska, Janina; Sochacka, Elzbieta

2011-04-01

4-Pyrimidinone ribofuranoside (H(2)o(4)U) and 4-pyrimidinone 2'-deoxyribofuranoside (dH(2)o(4)U) were synthesized by the oxidative desulfurization of parent 2-thiouracil nucleosides with m-chloroperbenzoic acid. The crystal structures of H(2)o(4)U and dH(2)o(4)U and their conformations in solution were determined and compared with corresponding 2-thiouracil and uracil nucleosides. The absence of a large 2-thiocarbonyl/2-carbonyl group in the nucleobase moiety results in C2'-endo puckering of the ribofuranose ring (S conformer) in the crystal structure of H(2)o(4)U, which is not typical of RNA nucleosides. Interestingly, the hydrogen bonding network in the crystals of dH(2)o(4)U stabilizes the sugar moiety conformation in the C3'-endo form (N conformer), rarely found in DNA nucleosides. In aqueous solution, dH(2)o(4)U reveals a similar population of the C2'-endo conformation (65%) to that of 2'-deoxy-2-thiouridine (62%), while the 62% population of the S conformer for H(2)o(4)U is significantly different from that of the parent 2-thiouridine, for which the N conformer is dominant (71%). Such a difference may be of biological importance, as the desulfurization process of natural tRNA 2-thiouridines may occur under conditions of oxidative stress in the cell and may influence the decoding process. Copyright © 2011 Elsevier Ltd. All rights reserved.

Sugar analog synthesis by in vitro biocatalytic cascade: A comparison of alternative enzyme complements for dihydroxyacetone phosphate production as a precursor to rare chiral sugar synthesis

PubMed Central

French, Nigel G.; Scoble, Judith A.; Williams, Charlotte C.; Churches, Quentin I.; Frazer, Andrew R.; Taylor, Matthew C.; Coia, Greg; Simpson, Gregory; Turner, Nicholas J.; Scott, Colin

2017-01-01

Carbon-carbon bond formation is one of the most challenging reactions in synthetic organic chemistry, and aldol reactions catalysed by dihydroxyacetone phosphate-dependent aldolases provide a powerful biocatalytic tool for combining C-C bond formation with the generation of two new stereo-centres, with access to all four possible stereoisomers of a compound. Dihydroxyacetone phosphate (DHAP) is unstable so the provision of DHAP for DHAP-dependent aldolases in biocatalytic processes remains complicated. Our research has investigated the efficiency of several different enzymatic cascades for the conversion of glycerol to DHAP, including characterising new candidate enzymes for some of the reaction steps. The most efficient cascade for DHAP production, comprising a one-pot four-enzyme reaction with glycerol kinase, acetate kinase, glycerophosphate oxidase and catalase, was coupled with a DHAP-dependent fructose-1,6-biphosphate aldolase enzyme to demonstrate the production of several rare chiral sugars. The limitation of batch biocatalysis for these reactions and the potential for improvement using kinetic modelling and flow biocatalysis systems is discussed. PMID:29112947

Chitosan-based biocatalytic nanoparticles for pollutant removal from wastewater.

PubMed

Alarcón-Payán, Dulce A; Koyani, Rina D; Vazquez-Duhalt, Rafael

2017-05-01

Chitosan, a renewable biopolymer has the prospective applications in different fields due to its gelation capacity. Nanoconfiguration of chitosan through ionotropic gelation to encapsulate enzymatic activity offers numerous potential applications. In the present study, the preparation and characterization of chitosan nanoparticles loaded with versatile peroxidase are reported. Their performance in bioremediation process and the resistance enhancement against natural microbial biodegradation were studied. The average diameter of enzymatic nanoparticles was 120nm and showed a high enzyme loading capacity. The kinetic parameters of nanoparticles exhibited a slightly lower catalytic activity (k cat ), similar affinity constant (Km) for hydrogen peroxide and higher Km value for the phenolic compound when compared with the free enzyme. The enzymatic nanoparticles showed higher thermostability and the same pH activity profile than those from free enzyme. Ten phenolic compounds, including pesticides, halogenated compounds, endocrine disruptors and antibacterials were transformed by the enzymatic nanoparticles. The transformation rate was lower than those obtained with free enzyme suggesting mass transfer limitations. But very importantly, the enzymatic nanoparticles showed a significant increase of the operational stability in real conditions of wastewater treatment process. Moreover, chemical modification of nanoparticles with different aldehydes still enhanced the operational stability of nanoparticulated enzymes. This enhancement of stability in real conditions and the potential use of biocatalytic nanoparticles in bioremediation processes are discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

A fiber optics system for monitoring utilization of ZnO adsorbent beds during desulfurization for logistic fuel cell applications

NASA Astrophysics Data System (ADS)

Sujan, Achintya; Yang, Hongyun; Dimick, Paul; Tatarchuk, Bruce J.

2016-05-01

An in-situ fiber optic based technique for direct measurement of capacity utilization of ZnO adsorbent beds by monitoring bed color changes during desulfurization for fuel cell systems is presented. Adsorbents composed of bulk metal oxides (ZnO) and supported metal oxides (ZnO/SiO2 and Cusbnd ZnO/SiO2) for H2S removal at 22 °C are examined. Adsorbent bed utilization at breakthrough is determined by the optical sensor as the maximum derivative of area under UV-vis spectrum from 250 to 800 nm observed as a function of service time. Since the response time of the sensor due to bed color change is close to bed breakthrough time, a series of probes along the bed predicts utilization of the portion of bed prior to H2S breakthrough. The efficacy of the optical sensor is evaluated as a function of inlet H2S concentration, H2S flow rate and desulfurization in presence of CO, CO2 and moisture in feed. A 6 mm optical probe is employed to measure utilization of a 3/16 inch ZnO extrudate bed for H2S removal. It is envisioned that with the application of the optical sensor, desulfurization can be carried out at high adsorbent utilization and low operational costs during on-board miniaturized fuel processing for logistic fuel cell power systems.

Deep extractive and oxidative desulfurization of dibenzothiophene with C5H9NO·SnCl2 coordinated ionic liquid.

PubMed

Li, Fa-tang; Kou, Cheng-guang; Sun, Zhi-min; Hao, Ying-juan; Liu, Rui-hong; Zhao, Di-shun

2012-02-29

A new C5H9NO·SnCl2 coordinated ionic liquid (IL) was prepared by reacting N-methyl-pyrrolidone with anhydrous SnCl2. Desulfurization of dibenzothiophene (DBT) via extraction and oxidation with C5H9NO·SnCl2 IL as extractant, H2O2 and equal mol of CH3COOH as oxidants was investigated. The Nernst partition coefficients k(N) of C5H9NO·SnCl2 IL for the DBT in n-octane was above 5.0, showing its excellent extraction ability. During the oxidative desulfurization process, the optimal molar ratio of H2O2/DBT was six. Sulfur removal of DBT in n-octane was 94.8% in 30 min at 30 °C under the conditions of H2O2/DBT molar ratio of six and V (IL):V (oil)=1:3. Moreover, the sulfur removal increased with increasing temperature because of the high reaction rate constant, low viscosity, and high solubility of dibenzothiophene-sulfone in the IL. The kinetics of oxidative desulfurization of DBT was also investigated, and the apparent activation energy was found to be 32.5 kJ/mol. The IL could be recycled six times without a significant decrease in activity. Copyright © 2011 Elsevier B.V. All rights reserved.

The Gonzaga desulfurization flue gas process

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

Kelleher, R.L.; O'Leary, T.J.; Shirk, I.A.

1984-01-01

The Gonzaga desulfurization flue gas process removes sulfur dioxide from a flue by cold water scrubbing. Sulfur dioxide is significantly more soluable in cold water (35/sup 0/F to 60/sup 0/F) than in warm water (100/sup 0/F). Sulfur dioxide reacts in water similarly as carbon dioxide reacts in water, in that both gasses are released from the water as the temperature of the water increases. The researchers at the Gonzaga University developed this process from the observations and techniques used in studying the acid and aldehyde concentrations in flue gasses with varying of fuel to air ratios. The apparatus was fixedmore » to a stationary engine and a gas/oil fired boiler. The flue gas was cooled to the dew point temperature of the air entering the combustion chamber on the pre-air heater. The system is described in two parts: the energies required for cooling in the scrubbing section and the energies required in the treatment section. The cold flue gas is utilized in cooling the scrubber section.« less

Theoretical investigation of the interaction between aromatic sulfur compounds and [BMIM](+)[FeCl4](-) ionic liquid in desulfurization: A novel charge transfer mechanism.

PubMed

Li, Hongping; Zhu, Wenshuai; Chang, Yonghui; Jiang, Wei; Zhang, Ming; Yin, Sheng; Xia, Jiexiang; Li, Huaming

2015-06-01

In this work, interaction nature between a group of aromatic sulfur compounds and [BMIM](+)[FeCl4](-) have been investigated by density functional theory (DFT). A coordination structure is found to be critical to the mechanism of extractive desulfurization. Interaction energy and extractive selectivity follow the order: thiophene (TH)desulfurization is attributed to the charge transfer effect. During extractive desulfurization, electrons on aromatic sulfur compounds transfer into the Lewis part of ionic liquid, namely, [FeCl4](-). Furthermore, it is better to consider the Lewis acidity of Fe-containing ionic liquid by the whole unit (such as [FeCl4](-) and aromatic sulfur compounds (X)) rather than only Fe or S atom. Copyright © 2015 Elsevier Inc. All rights reserved.

Advances on simultaneous desulfurization and denitrification using activated carbon irradiated by microwaves.

PubMed

Ma, Shuang-Chen; Gao, Li; Ma, Jing-Xiang; Jin, Xin; Yao, Juan-Juan; Zhao, Yi

2012-06-01

This paper describes the research background and chemistry of desulfurization and denitrification technology using microwave irradiation. Microwave-induced catalysis combined with activated carbon adsorption and reduction can reduce nitric oxide to nitrogen and sulfur dioxide to sulfur from flue gas effectively. This paper also highlights the main drawbacks of this technology and discusses future development trends. It is reported that the removal of sulfur dioxide and nitric oxide using microwave irradiation has broad prospects for development in the field of air pollution control.

Fabrication of a multiplexed microfluidic system for scaled up production of cross-linked biocatalytic microspheres

NASA Astrophysics Data System (ADS)

Mbanjwa, Mesuli B.; Chen, Hao; Fourie, Louis; Ngwenya, Sibusiso; Land, Kevin

2014-06-01

Multiplexed or parallelised droplet microfluidic systems allow for increased throughput in the production of emulsions and microparticles, while maintaining a small footprint and utilising minimal ancillary equipment. The current paper demonstrates the design and fabrication of a multiplexed microfluidic system for producing biocatalytic microspheres. The microfluidic system consists of an array of 10 parallel microfluidic circuits, for simultaneous operation to demonstrate increased production throughput. The flow distribution was achieved using a principle of reservoirs supplying individual microfluidic circuits. The microfluidic devices were fabricated in poly (dimethylsiloxane) (PDMS) using soft lithography techniques. The consistency of the flow distribution was determined by measuring the size variations of the microspheres produced. The coefficient of variation of the particles was determined to be 9%, an indication of consistent particle formation and good flow distribution between the 10 microfluidic circuits.

Evaluation of flue-gas desulfurization gypsum in poultry litter as a substrate component for greenhouse horticultural crops

USDA-ARS?s Scientific Manuscript database

A study was conducted to evaluate the growth response and consumer preference of three plant species to substrate blends containing flue gas desulfurization gypsum (FGDG). Substrate blends used in this study were derived from a previous experiment that evaluated the use of FGD Gas a bedding material...

Microbiome and Biocatalytic Bacteria in Monkey Cup (Nepenthes Pitcher) Digestive Fluid.

PubMed

Chan, Xin-Yue; Hong, Kar-Wai; Yin, Wai-Fong; Chan, Kok-Gan

2016-01-28

Tropical carnivorous plant, Nepenthes, locally known as "monkey cup", utilises its pitcher as a passive trap to capture insects. It then secretes enzymes into the pitcher fluid to digest the insects for nutrients acquisition. However, little is known about the microbiota and their activity in its pitcher fluid. Eighteen bacteria phyla were detected from the metagenome study in the Nepenthes pitcher fluid. Proteobacteria, Bacteroidetes and Actinobacteria are the dominant phyla in the Nepenthes pitcher fluid. We also performed culturomics approach by isolating 18 bacteria from the Nepenthes pitcher fluid. Most of the bacterial isolates possess chitinolytic, proteolytic, amylolytic, and cellulolytic and xylanolytic activities. Fifteen putative chitinase genes were identified from the whole genome analysis on the genomes of the 18 bacteria isolated from Nepenthes pitcher fluid and expressed for chitinase assay. Of these, six clones possessed chitinase activity. In conclusion, our metagenome result shows that the Nepenthes pitcher fluid contains vast bacterial diversity and the culturomic studies confirmed the presence of biocatalytic bacteria within the Nepenthes pitcher juice which may act in symbiosis for the turn over of insects trapped in the Nepenthes pitcher fluid.

Alloying effect of copper on the corrosion properties of low-alloy steel for flue gas desulfurization system

NASA Astrophysics Data System (ADS)

Kim, Seon-Hong; Park, Sun-Ah; Kim, Jung-Gu; Shin, Kee-Sam; He, Yinsheng

2015-03-01

The alloying effect of Cu for a flue gas desulfurization materials was investigated using the electrochemical methods in the modified green death solution and the surface analyses. The test results demonstrated that the densely formed rust layer with high metallic Cu content improves the corrosion resistance of Cu-containing steel in the flue gas desulfurization (FGD) environment. The rust layer on the surface of the 0.02 wt% Cu steel, which has an insufficient Cu content, was less protective than others. The 0.05 wt% Cu steel represented the highest corrosion resistance due to the formation of the densely formed rust layer with optimum Cu content. Because the free standing Cu2S precipitates had the insoluble characteristic in highly acidic solution, it produced the relatively porous Cu-enriched layer on the 0.08 wt% Cu steel surface. From these phenomena, the corrosion resistance of specimen decreased as the Cu content of specimen increased from 0.05 wt% to 0.08 wt%.

Polymeric carbon nitride nanomesh as an efficient and durable metal-free catalyst for oxidative desulfurization.

PubMed

Shen, Lijuan; Lei, Ganchang; Fang, Yuanxing; Cao, Yanning; Wang, Xinchen; Jiang, Lilong

2018-03-06

We report the first use of polymeric carbon nitride (CN) for the catalytic selective oxidation of H 2 S. The as-prepared CN with unique ultrathin "nanomeshes" structure exhibits excellent H 2 S conversion and high S selectivity. In particular, the CN nanomesh also displays better durability in the desulfurization reaction than traditional catalysts, such as carbon- and iron-based materials.

Development of a portable, modular unit for the optimization of ultrasound-assisted oxidative desulfurization of diesel

NASA Astrophysics Data System (ADS)

Wan, Meng-Wei

Due to the stringent rules requiring ultra-low sulfur content in diesel fuels, it is necessary to develop alternative methods of desulfurization of fossil fuel derived oil, such as diesel. Current technology is not sufficient to solve this problem. Ultrasound applied to oxidative desulfurization which combined three complementary techniques: ultrasonication, phase transfer catalysis (PTC) and transition metal catalyzed oxidation, has accomplished high sulfur removal in a short contact time at ambient temperature and atmospheric pressure. This research has successfully demonstrated that the higher oxidation efficiency of BT to BTO and free of any by-products by using tetraoctylammonium fluoride as phase transfer agent. The oxidation rate of BT to BTO increased with increasing the carbon chain length of QAS cations. Under the same length of carbon chain, the oxidation rate of BT to BTO increased with decreasing the molecular size of QAS anions. Moreover, for diesel fuels containing various levels of sulfur content, UAOD process followed by solvent extraction has demonstrated that the sulfur reduction can reach above 95 % removal efficiency or final sulfur content below 15 ppm in mild condition. For large-scale commercial production, this research has successfully developed and operated a continuous desulfurization unit, which consists of a sonoractor, an RF amplifier, a function generator, a pretreatment tank, and a pipeline system. A single unit only needed 2' x 4' x 1' space for installation. The results indicated that the remarkable 92% removal efficiency for the sulfur in marine logistic diesel, even at a treatment rate as high as 25 lb/hour which is approximately 2 barrels per day. Therefore, this sonoreactor demonstrated the feasibility of large-scale operation even in a relatively small installation with low capital investment and maintenance cost. It also ensures the safety considerations by operating with diluted hydrogen peroxide under ambient temperature

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

PubMed

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

2018-06-25

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

Adsorptive on-board desulfurization over multiple cycles for fuel-cell-based auxiliary power units operated by different types of fuels

NASA Astrophysics Data System (ADS)

Neubauer, Raphael; Weinlaender, Christof; Kienzl, Norbert; Bitschnau, Brigitte; Schroettner, Hartmuth; Hochenauer, Christoph

2018-05-01

On-board desulfurization is essential to operate fuel-cell-based auxiliary power units (APU) with commercial fuels. In this work, both (i) on-board desulfurization and (ii) on-board regeneration performance of Ag-Al2O3 adsorbent is investigated in a comprehensive manner. The herein investigated regeneration strategy uses hot APU off-gas as the regeneration medium and requires no additional reagents, tanks, nor heat exchangers and thus has remarkable advantages in comparison to state-of-the-art regeneration strategies. The results for (i) show high desulfurization performance of Ag-Al2O3 under all relevant operating conditions and specify the influence of individual operation parameters and the combination of them, which have not yet been quantified. The system integrated regeneration strategy (ii) shows excellent regeneration performance recovering 100% of the initial adsorption capacity for all investigated types of fuels and sulfur heterocycles. Even the adsorption capacity of the most challenging dibenzothiophene in terms of regeneration is restored to 100% over 14 cycles of operation. Subsequent material analyses proved the thermal and chemical stability of all relevant adsorption sites under APU off-gas conditions. To the best of our knowledge, this is the first time 100% regeneration after adsorption of dibenzothiophene is reported over 14 cycles of operation for thermal regeneration in oxidizing atmospheres.

A green surfactant-assisted synthesis of hierarchical TS-1 zeolites with excellent catalytic properties for oxidative desulfurization.

PubMed

Du, Shuting; Li, Fen; Sun, Qiming; Wang, Ning; Jia, Mingjun; Yu, Jihong

2016-02-25

Hierarchical TS-1 zeolites with uniform intracrystalline mesopores have been successfully synthesized through the hydrothermal method by using the green and cheap surfactant Triton X-100 as the mesoporous template. The resultant materials exhibit remarkably enhanced catalytic activity in oxidative desulfurization reactions compared to the conventional TS-1 zeolite.

Novel polyoxometalate silica nano-sized spheres: efficient catalysts for olefin oxidation and the deep desulfurization process.

PubMed

Nogueira, Lucie S; Ribeiro, Susana; Granadeiro, Carlos M; Pereira, Eulália; Feio, Gabriel; Cunha-Silva, Luís; Balula, Salete S

2014-07-07

A novel method to prepare silica nano-sized particles incorporating polyoxometalates was developed leading to a new efficient heterogeneous oxidative catalyst. Zinc-substituted polyoxotungstate [PW11Zn(H2O)O39](5-) (PW11Zn) was encapsulated into silica nanoparticles using a cross-linked organic-inorganic core, performed through successive spontaneous reactions in water. The potassium salt of PW11Zn and the composite formed, PW11Zn-APTES@SiO2, were characterized by a myriad of solid-state methods such as FT-IR, FT-Raman, (31)P and (13)C CP/MAS solid-state NMR, elemental analysis and SEM-EDS, confirming the integrity of the PW11Zn structure immobilized in the silica nanoparticles. The new composite has shown to be a versatile catalyst for the oxidation of olefins and also to catalyze the desulfurization of a model oil using H2O2 as the oxidant and acetonitrile as the solvent. The novel composite material was capable of being recycled without significant loss of activity and maintaining its structural stability for consecutive desulfurization and olefin oxidative cycles.

Ultra-Deep Adsorptive Desulfurization of Light-Irradiated Diesel Fuel over Supported TiO 2-CeO 2 Adsorbents

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

Xiao, Jing; Wang, Xiaoxing; Chen, Yongsheng

2014-02-13

This study investigates ultra-deep adsorptive desulfurization (ADS) from light-irradiated diesel fuel over supported TiO 2–CeO 2 adsorbents. A 30-fold higher desulfurization capacity of 95 mL of fuel per gram of adsorbent (mL-F/g-sorb) or 1.143 mg of sulfur per gram of adsorbent (mg-S/g-sorb) was achieved from light-irradiated fuel over the original low-sulfur fuel containing about 15 ppm by weight (ppmw) of sulfur. The sulfur species on spent TiO 2–CeO 2/MCM-48 adsorbent was identified by sulfur K-edge XANES as sulfones and the adsorption selectivity to different compounds tested in a model fuel decreases in the order of indole > dibenzothiophenesulfone → dibenzothiophenemore » > 4-methyldibenzothiophene > benzothiophene > 4,6-dimethyldibenzothiophene > phenanthrene > 2-methylnaphthalene ~ fluorene > naphthalene. The results suggest that during ADS of light-irradiated fuel, the original sulfur species were chemically transformed to sulfones, resulting in the significant increase in desulfurization capacity. For different supports for TiO2–CeO2 oxides, the ADS capacity increases with a decrease in the point of zero charge (PZC) value; for silica-supported TiO 2–CeO 2 oxides (the lowest PZC value of 2–4) with different surface areas, the ADS capacity increases monotonically with increasing surface area. The supported TiO 2–CeO 2/MCM-48 adsorbent can be regenerated using oxidative air treatment. The present study provides an attractive new path to achieve ultraclean fuel more effectively.« less

Simultaneous destraction and desulfurization of Illinois coals with supercritical ethanol

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

Wu, B.C.

1983-01-01

Various Illinois coals (with Illinois number6 being the main one) are liquefied with various supercritical solvents (ethanol being the main solvent) at 543-598 K, system pressures of 6.99-24.23 MPa, flow rates of 3.0-7.5 ml/min, reaction time of 0-180 minutes, and coal particle sizes of 0.36-0.85 mm to 1.00-2.36 mm to systematically investigate the effects of flow rates, reaction time, coal particle size, temperature, pressure, coal characteristics (by using different Illinois coals), supercritical medium (by using different solvents), and the addition of potassium hydroxide. The % weight loss of coal and the % sulfur removal during destraction and desulfurization of coalmore » are functions of the flow rate, the reaction time, the coal particle size, temperature, pressure and the supercritical solvent. Temperature, pressure and the supercritical medium are the most important parameters in controlling the % weight loss of coal and the % sulfur removal. The % weight loss of coal can be related to a power law and fits quite nicely into a second order kinetic model. The % sulfur removal also follows a second order kinetic model. A secondary reaction is observed during the destraction process, which implies that destraction, and possibly desulfurization, of coal is a multistep reaction including a physical extraction step where the major portion of the coal and sulfur was removed and then followed by a chemical reaction. Supercritical ethanol definitely enhances the removal of sulfur compounds from coal. The enhanced selectivity by supercritical ethanol is greatest at a pressure just above the critical pressure of ethanol. Finally, addition of a base such as potassium hydroxide enhances both % weight loss of coal and the % sulfur removal.« less

A template-free solvent-mediated synthesis of high surface area boron nitride nanosheets for aerobic oxidative desulfurization.

PubMed

Wu, Peiwen; Zhu, Wenshuai; Chao, Yanhong; Zhang, Jinshui; Zhang, Pengfei; Zhu, Huiyuan; Li, Changfeng; Chen, Zhigang; Li, Huaming; Dai, Sheng

2016-01-04

Hexagonal boron nitride nanosheets (h-BNNs) with rather high specific surface area (SSA) are important two-dimensional layer-structured materials. Here, a solvent-mediated synthesis of h-BNNs revealed a template-free lattice plane control strategy that induced high SSA nanoporous structured h-BNNs with outstanding aerobic oxidative desulfurization performance.

Biocatalytic anti-Prelog reduction of prochiral ketones with whole cells of Acetobacter pasteurianus GIM1.158

PubMed Central

2014-01-01

Background Enantiomerically pure alcohols are important building blocks for production of chiral pharmaceuticals, flavors, agrochemicals and functional materials and appropriate whole-cell biocatalysts offer a highly enantioselective, minimally polluting route to these valuable compounds. At present, most of these biocatalysts follow Prelog’s rule, and thus the (S)-alcohols are usually obtained when the smaller substituent of the ketone has the lower CIP priority. Only a few anti-Prelog (R)-specific whole cell biocatalysts have been reported. In this paper, the biocatalytic anti-Prelog reduction of 2-octanone to (R)-2-octanol was successfully conducted with high enantioselectivity using whole cells of Acetobacter pasteurianus GIM1.158. Results Compared with other microorganisms investigated, Acetobacter pasteurianus GIM1.158 was shown to be more effective for the reduction reaction, affording much higher yield, product enantiomeric excess (e.e.) and initial reaction rate. The optimal temperature, buffer pH, co-substrate and its concentration, substrate concentration, cell concentration and shaking rate were 35°C, 5.0, 500 mmol/L isopropanol, 40 mmol/L, 25 mg/mL and 120 r/min, respectively. Under the optimized conditions, the maximum yield and the product e.e. were 89.5% and >99.9%, respectively, in 70 minutes. Compared with the best available data in aqueous system (yield of 55%), the yield of (R)-2-octanol was greatly increased. Additionally, the efficient whole-cell biocatalytic process was feasible on a 200-mL preparative scale and the chemical yield increased to 95.0% with the product e.e. being >99.9%. Moreover, Acetobacter pasteurianus GIM1.158 cells were proved to be capable of catalyzing the anti-Prelog bioreduction of other prochiral carbonyl compounds with high efficiency. Conclusions Via an effective increase in the maximum yield and the product e.e. with Acetobacter pasteurianus GIM1.158 cells, these results open the way to use of whole cells of

Biocatalytic anti-Prelog reduction of prochiral ketones with whole cells of Acetobacter pasteurianus GIM1.158.

PubMed

Du, Peng-Xuan; Wei, Ping; Lou, Wen-Yong; Zong, Min-Hua

2014-06-10

Enantiomerically pure alcohols are important building blocks for production of chiral pharmaceuticals, flavors, agrochemicals and functional materials and appropriate whole-cell biocatalysts offer a highly enantioselective, minimally polluting route to these valuable compounds. At present, most of these biocatalysts follow Prelog's rule, and thus the (S)-alcohols are usually obtained when the smaller substituent of the ketone has the lower CIP priority. Only a few anti-Prelog (R)-specific whole cell biocatalysts have been reported. In this paper, the biocatalytic anti-Prelog reduction of 2-octanone to (R)-2-octanol was successfully conducted with high enantioselectivity using whole cells of Acetobacter pasteurianus GIM1.158. Compared with other microorganisms investigated, Acetobacter pasteurianus GIM1.158 was shown to be more effective for the reduction reaction, affording much higher yield, product enantiomeric excess (e.e.) and initial reaction rate. The optimal temperature, buffer pH, co-substrate and its concentration, substrate concentration, cell concentration and shaking rate were 35°C, 5.0, 500 mmol/L isopropanol, 40 mmol/L, 25 mg/mL and 120 r/min, respectively. Under the optimized conditions, the maximum yield and the product e.e. were 89.5% and >99.9%, respectively, in 70 minutes. Compared with the best available data in aqueous system (yield of 55%), the yield of (R)-2-octanol was greatly increased. Additionally, the efficient whole-cell biocatalytic process was feasible on a 200-mL preparative scale and the chemical yield increased to 95.0% with the product e.e. being >99.9%. Moreover, Acetobacter pasteurianus GIM1.158 cells were proved to be capable of catalyzing the anti-Prelog bioreduction of other prochiral carbonyl compounds with high efficiency. Via an effective increase in the maximum yield and the product e.e. with Acetobacter pasteurianus GIM1.158 cells, these results open the way to use of whole cells of this microorganism for

Study on optimum technological conditions of ore sintering flue gas desulfurization by using poor manganese

NASA Astrophysics Data System (ADS)

Li, H. Y.; Li, S. E.; Long, Z. G.; Wu, F. Z.; Cui, T. M.; Zhou, X. Z.

2017-11-01

Orthogonal experiments were conducted to study the effect of each single factor on the desulfurization rate and leaching rate of Mn2+ to obtain improved process parameters. The results showed that the use of pyrolusite flue gas and the process method of by-product MnSO4 can not only effectively remove the sulfur in the gas, thereby controlling environmental pollution, but can also recover sulfur.

Investigation on the Influence of Bio-catalytic Enzyme Produced from Fruit and Vegetable Waste on Palm Oil Mill Effluent

NASA Astrophysics Data System (ADS)

Rasit, Nazaitulshila; Chee Kuan, Ooi

2018-04-01

Pre-consumer waste from supermarkets, such as vegetables and fruits dreg are always discarded as solid waste and disposed to landfill. Implementing waste recovery method as a form of waste management strategy will reduce the amount of waste disposed. One of the ways to achieve this goal is through fermentation of the pre-consumer supermarket waste to produce a solution known as garbage enzyme. This study has been conducted to produce and characterize biocatalytic garbage enzyme and to evaluate its influence on palm oil mill effluent as a pre-treatment process before further biological process takes place. Garbage enzyme was produced by three-month long fermentation of a mixture of molasses, pre-consumer supermarket residues, and water in the ratio of 1:3:10. Subsequently, the characterization of enzyme was conducted based on pH, total solids (TS), total suspended solids (TSS), total dissolved solids (TDS), chemical oxygen demand (COD), and enzyme activities. The influence of produced enzyme was evaluated on oil & grease (O&G), TSS and COD of palm oil mill effluent (POME). Different levels of dilution of garbage enzyme to POME samples (5%, 10%, 15%) were explored as pre-treatment (duration of six days) and the results showed that the garbage enzyme contained bio-catalytic enzyme such as amylase, protease, and lipase. The pre-treatment showed removal of 90% of O&G in 15% dilution of garbage enzyme. Meanwhile, reduction of TSS and COD in dilution of 10% garbage enzyme were measured at 50% and 25% respectively. The findings of this study are important to analyse the effectiveness of pre-treatment for further improvement of anaerobic treatment process of POME, especially during hydrolysis stage.

(18)O(2) label mechanism of sulfur generation and characterization in properties over mesoporous Sm-based sorbents for hot coal gas desulfurization.

PubMed

Liu, B S; Wan, Z Y; Wang, F; Zhan, Y P; Tian, M; Cheung, A S C

2014-02-28

Using a sol-gel method, SmMeOx/MCM-41 or SBA-15 (Me=Fe, Co and Zn) and corresponding unsupported sorbents were prepared. The desulfurization performance of these sorbents was evaluated over a fixed-bed reactor and the effects of reaction temperature, feed and sorbent composition on desulfurization performance were studied. Samarium-based sorbents used to remove H2S from hot coal gas were reported for the first time. The results of successive sulfidation/regeneration cycles revealed that SmFeO3/SBA-15 sorbent was suitable for desulfurization of hot coal gas in the chemical industry. The formation of elemental sulfur during both sulfidation and regeneration processes depended strongly on the catalytic action of Sm2O2S species, which was confirmed for the first time via high sensitive time of flight mass spectrometer (TOF-MS) using 6%vol(18)O2/Ar regeneration gas and can reduce markedly procedural complexity. The sorbents were characterized using N2-adsorption, high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), temperature-programmed reduction of H2 (H2-TPR), thermogravimetry (TG) and time-of-flight mass spectrometry (TOF-MS) techniques. Copyright © 2014 Elsevier B.V. All rights reserved.

Desulfurization of dibenzothiophene by Corynebacterium sp. strain SY1.

PubMed Central

Omori, T; Monna, L; Saiki, Y; Kodama, T

1992-01-01

Strain SY1, identified as a Corynebacterium sp., was isolated on the basis of the ability to utilize dibenzothiophene (DBT) as a sole source of sulfur. Strain SY1 could utilize a wide range of organic and inorganic sulfur compounds, such as DBT sulfone, dimethyl sulfide, dimethyl sulfoxide, dimethyl sulfone, CS2, FeS2, and even elemental sulfur. Strain SY1 metabolized DBT to dibenzothiophene-5-oxide, DBT sulfone, and 2-hydroxybiphenyl, which was subsequently nitrated to produce at least two different hydroxynitrobiphenyls during cultivation. These metabolites were separated by silica gel column chromatography and identified by nuclear magnetic resonance, UV, and mass spectral techniques. Resting cells of SY1 desulfurized toluenesulfonic acid and released sulfite anion. On the basis of these results, a new DBT degradation pathway is proposed. PMID:1575493

A template-free solvent-mediated synthesis of high surface area boron nitride nanosheets for aerobic oxidative desulfurization

DOE PAGES

Wu, Peiwen; Zhu, Wenshuai; Chao, Yanhong; ...

2015-10-16

Hexagonal boron nitride nanosheets (h-BNNs) with rather high specific surface area (SSA) are important two-dimensional layer-structured materials. Here in this study, a solvent-mediated synthesis of h-BNNs revealed a template-free lattice plane control strategy that induced high SSA nanoporous structured h-BNNs with outstanding aerobic oxidative desulfurization performance.

Research on Identification and Screen of Microbial Desulfurization Strains for Petroleum

NASA Astrophysics Data System (ADS)

Xiaojuan, Tian; Lingtian, Tang; Li'e, Peng; Xinghong, Li

The oil-contaminated soil sample was acquired from Shengli Oilfield and Jidong Oilfield and cultured with enrichment technology. Then 21 desulfurization strains were separated from the sample, from which a high efficiency desulfurization strain TV9704 was selected. The strain could neither grow with n-dodecane, n-hexadecane, liquid paraffin, naphthalene or diesel as a carbon source and energy source, nor obviously reduce oil combustion value. It could use thiophene or dibenzothiophene (DBT) as the sole sulfur source. In the experiment, the concentrations of thiophene and DBT were measured by UV spectrophotometer. After being cultured in the culture medium with an initial concentration of 63.2 mmol/L respectively for 48 h and 144 h, the degradation rates of the strain TV9704 on thiophene were 39.0% and 63.8%; the DBT with an initial concentration of 2.7 mmol/L was degraded by 1.46 mmol/L after cultured for 72 h. When sodium acetate and glycerol were chosen as carbon source, the ethanol could enhance the degradation rate of TV9704 on DBT significantly. Strain TV9704 was identified by China Industrial Culture Collection Center (CICC) as a Bacillus sp., Gram-positive, obligate aerobic, which forms a circular orange colony on the nutrition gravy plate. The 16SrDNA gene sequencing test and analysis was carried out on strain TV9704, finding that its homologies with the most similar species Bacillus aquimaris and Bacillus marisflavi were 99.2% and 98.2% respectively, but a larger difference existed between their cell morphological characteristics and physiological and biochemical characteristics, therefore strain TV9704 may be a new species because it was impossible to be categorized to any population.

Selective oxidation of aliphatic C-H bonds in alkylphenols by a chemomimetic biocatalytic system.

PubMed

Du, Lei; Dong, Sheng; Zhang, Xingwang; Jiang, Chengying; Chen, Jingfei; Yao, Lishan; Wang, Xiao; Wan, Xiaobo; Liu, Xi; Wang, Xinquan; Huang, Shaohua; Cui, Qiu; Feng, Yingang; Liu, Shuang-Jiang; Li, Shengying

2017-06-27

Selective oxidation of aliphatic C-H bonds in alkylphenols serves significant roles not only in generation of functionalized intermediates that can be used to synthesize diverse downstream chemical products, but also in biological degradation of these environmentally hazardous compounds. Chemo-, regio-, and stereoselectivity; controllability; and environmental impact represent the major challenges for chemical oxidation of alkylphenols. Here, we report the development of a unique chemomimetic biocatalytic system originated from the Gram-positive bacterium Corynebacterium glutamicum The system consisting of CreHI (for installation of a phosphate directing/anchoring group), CreJEF/CreG/CreC (for oxidation of alkylphenols), and CreD (for directing/anchoring group offloading) is able to selectively oxidize the aliphatic C-H bonds of p - and m -alkylated phenols in a controllable manner. Moreover, the crystal structures of the central P450 biocatalyst CreJ in complex with two representative substrates provide significant structural insights into its substrate flexibility and reaction selectivity.

Selective oxidation of aliphatic C–H bonds in alkylphenols by a chemomimetic biocatalytic system

PubMed Central

Du, Lei; Dong, Sheng; Zhang, Xingwang; Jiang, Chengying; Chen, Jingfei; Yao, Lishan; Wang, Xiao; Wan, Xiaobo; Liu, Xi; Wang, Xinquan; Huang, Shaohua; Cui, Qiu; Liu, Shuang-Jiang; Li, Shengying

2017-01-01

Selective oxidation of aliphatic C–H bonds in alkylphenols serves significant roles not only in generation of functionalized intermediates that can be used to synthesize diverse downstream chemical products, but also in biological degradation of these environmentally hazardous compounds. Chemo-, regio-, and stereoselectivity; controllability; and environmental impact represent the major challenges for chemical oxidation of alkylphenols. Here, we report the development of a unique chemomimetic biocatalytic system originated from the Gram-positive bacterium Corynebacterium glutamicum. The system consisting of CreHI (for installation of a phosphate directing/anchoring group), CreJEF/CreG/CreC (for oxidation of alkylphenols), and CreD (for directing/anchoring group offloading) is able to selectively oxidize the aliphatic C–H bonds of p- and m-alkylated phenols in a controllable manner. Moreover, the crystal structures of the central P450 biocatalyst CreJ in complex with two representative substrates provide significant structural insights into its substrate flexibility and reaction selectivity. PMID:28607077

Utilization of a by-product produced from oxidative desulfurization process over Cs-mesoporous silica catalysts.

PubMed

Kim, Hyeonjoo; Jeong, Kwang-Eun; Jeong, Soon-Yong; Park, Young-Kwon; Kim, Do Heui; Jeon, Jong-Ki

2011-02-01

We investigated the use of Cs-mesoporous silica catalysts to upgrade a by-product of oxidative desulfurization (ODS). Cs-mesoporous silica catalysts were characterized through N2 adsorption, XRD, CO2-temperature-programmed desorption, and XRF. Cs-mesoporous silica prepared by the direct incorporation method showed higher catalytic performance than a Cs/MCM-41 catalyst by impregnation method for the catalytic decomposition of sulfone compounds produced from ODS process.

Biocatalytic methanation of hydrogen and carbon dioxide in an anaerobic three-phase system.

PubMed

Burkhardt, M; Koschack, T; Busch, G

2015-02-01

A new type of anaerobic trickle-bed reactor was used for biocatalytic methanation of hydrogen and carbon dioxide under mesophilic temperatures and ambient pressure in a continuous process. The conversion of gaseous substrates through immobilized hydrogenotrophic methanogenic archaea in a biofilm is a unique feature of this type of reactor. Due to the formation of a three-phase system on the carrier surface and operation as a plug flow reactor without gas recirculation, a complete reaction could be observed. With a methane concentration higher than c(CH4) = 98%, the product gas exhibits a very high quality. A specific methane production of P(CH4) = 1.49 Nm(3)/(m(3)(SV) d) was achieved at a hydraulic loading rate of LR(H2) = 6.0 Nm(3)/(m(3)(SV) d). The relation between trickle flow through the reactor and productivity could be shown. An application for methane enrichment in combination with biogas facilities as a source of carbon dioxide has also been positively proven. Copyright © 2014 Elsevier Ltd. All rights reserved.

Multifunctionalized biocatalytic P22 nanoreactor for combinatory treatment of ER+ breast cancer.

PubMed

Chauhan, Kanchan; Hernandez-Meza, Juan M; Rodríguez-Hernández, Ana G; Juarez-Moreno, Karla; Sengar, Prakhar; Vazquez-Duhalt, Rafael

2018-02-20

Tamoxifen is the standard endocrine therapy for breast cancers, which require metabolic activation by cytochrome P450 enzymes (CYP). However, the lower and variable concentrations of CYP activity at the tumor remain major bottlenecks for the efficient treatment, causing severe side-effects. Combination nanotherapy has gained much recent attention for cancer treatment as it reduces the drug-associated toxicity without affecting the therapeutic response. Here we show the modular design of P22 bacteriophage virus-like particles for nanoscale integration of virus-driven enzyme prodrug therapy and photodynamic therapy. These virus capsids carrying CYP activity at the core are decorated with photosensitizer and targeting moiety at the surface for effective combinatory treatment. The estradiol-functionalized nanoparticles are recognized and internalized into ER+ breast tumor cells increasing the intracellular CYP activity and showing the ability to produce reactive oxygen species (ROS) upon UV 365 nm irradiation. The generated ROS in synergy with enzymatic activity drastically enhanced the tamoxifen sensitivity in vitro, strongly inhibiting tumor cells. This work clearly demonstrated that the targeted combinatory treatment using multifunctional biocatalytic P22 represents the effective nanotherapeutics for ER+ breast cancer.

Feasibility Study of Coal Gasification/Fuel Cell/Cogeneration Project. Fort Hood, Texas Site. Project Description,

DTIC Science & Technology

1985-07-01

and Operation 132 6.7.5 Safety 135 6.7.6 System Control Description 136 6.7.6.1 Coal Gasification 136 6.7.6.2 Gas Cooling, Cleaning and Compression...the hydrogen content. The gas is then desulfurized and heated before final polishing and feeding to the fuel cell. Receiving compressed fuel gas and...4 CO Shift 1 Stretford Desulfurizer 3 Gas Compressors 3 Material Handling(3) 3 Subtotal 39 Scheduled Shutdown 14 Total Annual Shutdown 53

Desulfurization of dibenzothiophene by Corynebacterium sp. strain SY1

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

Omori, Toshio; Monna, L.; Saiki, Yuko

1992-03-01

Strain SY1, identified as a Corynebacterium sp., was isolated on the basis of the ability to utilize dibenzothiophene (DBT) as a sole source of sulfur. Strain SY1 could utilize a wide range of organic and inorganic sulfur compounds, such as DBT sulfone, dimethyl sulfide, dimethyl sulfoxide, dimethyl sulfone, CS{sub 2}, FeS{sub 2}, and even elemental sulfur. Strain SY1 metabolized DBT to dibenzothiophene-5-oxide, DBT sulfone, and 2-hydroxybiphenyl, which was subsequently nitrated to produce at least two different hydroxynitrobiphenyls during cultivation. These metabolites were separated by silica gel column chromatography and identified by nuclear magnetic resonance, UV, and mass spectral techniques. Restingmore » cells of SY1 desulfurized toluenesulfonic acid and released sulfite anion. On the basis of these results, a new DBT degradation pathway is proposed.« less

Mercury emission and plant uptake of trace elements during early stage of soil amendment using flue gas desulfurization materials.

USDA-ARS?s Scientific Manuscript database

A pilot-scale field study was carried out to investigate the distribution of Hg and other selected elements in the three potential mitigation pathways, i.e., emission to ambient air, uptake by surface vegetation (i.e., grass), and rainfall infiltration, after flue gas desulfurization (FGD) material ...

The control of H2S in biogas using iron ores as in situ desulfurizers during anaerobic digestion process.

PubMed

Zhou, Qiying; Jiang, Xia; Li, Xi; Jiang, Wenju

2016-09-01

In this study, five kinds of iron ores, limonite, hematite, manganese ore, magnetite and lava rock, were used as the in situ desulfurizers in the anaerobic digestion reactors to investigate their effects on controlling H2S in biogas. The results show that the addition of the five iron ores could significantly control the content of H2S in biogas, with the best performance for limonite. As limonite dosages increase (10-60 g/L), the contents of H2S in biogas were evidently decreased in the digesters with different initial sulfate concentrations (0-1000 mg/L). After the anaerobic digestion, the removed sulfur was mostly deposited on the surface of limonite. A possible mechanism of H2S control in biogas by limonite was proposed preliminarily, including adsorption, FeS precipitation, and Fe (III) oxidation. The results demonstrated that limonite was a promising in situ desulfurizer for controlling H2S in biogas with low cost and high efficiency.

Metals in soil and runoff from a piedmont hayfield amended with broiler litter and flue gas desulfurization gypsum

USDA-ARS?s Scientific Manuscript database

Flue gas desulfurization gypsum (FGDG) from coal-fired power plants is available for agricultural use in many US regions. Broiler litter (BL) provides plant available N, P, and K but may be a source of unwanted arsenic (As), copper (Cu), and zinc (Zn). FGDG provides Ca and S and can reduce runoff lo...

OH radicals generated by DC corona discharge for improving the pulsed discharge desulfuration efficiency.

PubMed

Li, Jie; Li, Guo-feng; Wu, Yan; Wang, Ning-hui; Huang, Qiu-nan

2004-01-01

Positive DC corona discharge is formed with needle-plate electrode configuration, in which the water vapor is ejected though the needle points. The purpose is to increase the numbers of the water-based radicals, ionize the water molecule and improve the desulfuration efficiency of pulsed corona reactor. The water ions were determined by four stages molecular beam mass spectrometer and diagnose the water-based radicals by emission spectrograph. A conclusion on formation of ions and radicals with DC corona discharges can be drawn.

Analysis on the Oversize Blast Furnace Desulfurization and a Sulfide Capacity Prediction Model Based on Congregated Electron Phase

NASA Astrophysics Data System (ADS)

Zhenyang, Wang; Jianliang, Zhang; Gang, An; Zhengjian, Liu; Zhengming, Cheng; Junjie, Huang; Jingwei, Zhang

2016-02-01

Through analyzed and regressed the actual productive desulfurization data from the oversize blast furnace (5500 m3) in north China, the relationship between the sulfur distribution parameters and the slag composition in actual production situation was investigated. As the slag and hot metal phases have their own balance sulfur content or sulfur partial pressure in gas phase, respectively, the non-equilibrium of sulfur among gas, slag, and metal phases leads to the transmission and distribution of sulfur. Combined with sulfur transmission reactions between gas, slag and metal phases, C/CO pairs equilibrium, and Wagner model, the measured sulfide capacity can be acquired using sulfur distribution ratio, sulfur activity coefficient, and oxygen activity in hot metal. Based on the theory of congregated electron phase, a new sulfide capacity prediction model (CEPM) has been developed, which has a good liner relationship with the measured sulfide capacity. Thus, using the burden structure for BF, the ironmaking slag composition can be obtained simply and can be used to reliably predict the ironmaking slag desulfurization ability a few hours later after charging under a certain temperature by CEPM.

Carbonate Minerals with Magnesium in Triassic Terebratula Limestone in the Term of Limestone with Magnesium Application as a Sorbent in Desulfurization of Flue Gases

NASA Astrophysics Data System (ADS)

Stanienda-Pilecki, Katarzyna

2017-09-01

This article presents the results of studies of Triassic (Muschelkalk) carbonate rock samples of the Terebratula Beds taken from the area of the Polish part of the Germanic Basin. It is the area of Opole Silesia. The rocks were studied in the term of possibility of limestone with magnesium application in desulfurization of flue gases executed in power plants. Characteristic features of especially carbonate phases including magnesium-low-Mg calcite, high-Mg calcite, dolomite and huntite were presented in the article. They were studied to show that the presence of carbonate phases with magnesium, especially high-Mg calcite makes the desulfurization process more effective. Selected rock samples were examined using a microscope with polarized, transmitted light, X-ray diffraction, microprobe measurements and FTIR spectroscopy. The results of studies show a domination of low magnesium calcite in the limestones of the Terebratula Beds. In some samples dolomite and lower amounts of high-Mg calcite occurred. Moreover, huntite was identified. The studies were very important, because carbonate phases like high-Mg calcite and huntite which occurred in rocks of the Triassic Terebratula Beds were not investigated in details by other scientists but they presence in limestone sorbent could influence the effectiveness of desulfurization process.

Transport—Reaction process in the reaction of flue gas desulfurization

NASA Astrophysics Data System (ADS)

Yan, Yan; Peng, Xiaofeng; Lee, Duu Jong

2000-12-01

A theoretical investigation was conducted to study the transport-reaction process in the spray-drying flue gas desulfurization. A transport-reaction model of single particle was proposed, which considered the water evaporation from the surface of droplet and the reaction at the same time. Based on this model, the reaction rate and the absorbent utilization can be calculated. The most appropriate particle radius and the initial absorbent concentration can be deduced through comparing the wet lifetime with the residence time, the result shows in the case that the partial pressure of vapor in the bulk flue gas is 2000Pa, the optimum initial radius and absorbent concentration are 210 310 µ m and 23% respectively. The model can supply the optimum parameters for semi-dry FGD system designed.

Biocatalytic Synthesis of Flavonoid Esters by Lipases and Their Biological Benefits.

PubMed

de Araújo, Maria Elisa M B; Franco, Yollanda E M; Messias, Marcia C F; Longato, Giovanna B; Pamphile, João A; Carvalho, Patricia de O

2017-01-01

Several studies have described important biological activities of flavonoids such as coronary heart disease prevention, hepatoprotective, anti-inflammatory and anticancer activities, enzyme inhibition activity, and antibacterial, antifungal, and antiviral activities. Flavonoids show promising activity as natural plant-based antioxidants due to their antioxidant and free radical scavenging properties. However, their primary applications as antioxidants in the pharmaceutical, cosmetic, and food industries are limited because of their moderately hydrophilic nature. Enzymatic acylation of natural polyphenols with fatty acids or other acyl donors has been suggested for improving the lipophilic nature of the glycosylated flavonoids. This approach increases flavonoid solubility and stability in lipophilic systems. Acylation of flavonoids with different acyl donors may also introduce beneficial properties to the molecule, such as penetration through the cell membrane and improved antioxidant, antimicrobial, anti-inflammatory, antiproliferative, cytogenetic, and enzyme inhibition activities. Chemical methods for the synthesis of flavonoid esters lead to the formation of side products and the simultaneous decomposition of the flavonoids due to harsh reaction conditions. In contrast, biocatalytic acylation of flavonoids by lipases offers advantages associated to the wide availability of these enzymes, their low cost, chemo-, regio-, and enantioselectivity, mild condition processing and non-requirement of cofactors. This article is focused on the recent development of lipase-catalyzed synthesis of flavonoid esters and the impact of the acylation reaction on their biological activities. Georg Thieme Verlag KG Stuttgart · New York.

The Stability of Lubricant Oil Acidity of Biogas Fuelled Engine due to Biogas Desulfurization

NASA Astrophysics Data System (ADS)

Gde Tirta Nindhia, Tjokorda; Wayan Surata, I.; Wardana, Ari

2017-05-01

This research is established for the purpose of the understanding the stability of the acidity of lubricant oil in biogas fuelled engine due to the absence of hydrogen sulfide (H2S). As was recognized that other than Methane (CH4), there are also other gas impurities in the biogas such as carbon dioxide (CO2), hydrogen sulfide (H2S), moisture (H2O) and ammonia (NH3). Due to H2S contents in the biogas fuel, the engine was found failure. This is caused by corrosion in the combustion chamber due to increase of lubricant acidity. To overcome this problem in practical, the lubricant is increased the pH to basic level with the hope will be decrease to normal value after several time use. Other method is by installing pH measurement sensor in the engine lubricant so that when lubricant is known turn to be acid, then lubricant replacement should be done. In this research, the effect of biogas desulfurization down to zero level to the acidity of lubricant oil in the four stroke engine was carried out with the hope that neutral lubrication oil to be available during running the engine. The result indicates that by eliminating H2S due desulfurization process, effect on stability and neutrality of pH lubricant. By this method the engine safety can be obtained without often replacement the lubricant oil.

Adsorption and Desulfurization Mechanism of Thiophene on Layered FeS(001), (011), and (111) Surfaces: A Dispersion-Corrected Density Functional Theory Study

PubMed Central

2017-01-01

Layered transition-metal chalcogenides have emerged as a fascinating new class of materials for catalysis. Here, we present periodic density functional theory (DFT) calculations of the adsorption of thiophene and the direct desulfurization reaction pathways on the (001), (011), and (111) surfaces of layered FeS. The fundamental aspects of the thiophene adsorption, including the initial adsorption geometries, adsorption energies, structural parameters, and electronic properties, are presented. From the calculated adsorption energies, we show that the flat adsorption geometries, wherein the thiophene molecule forms multiple π-bonds with the FeS surfaces, are energetically more favorable than the upright adsorption geometries, with the strength of adsorption decreasing in the order FeS(111) > FeS(011) > FeS(001). The adsorption of the thiophene onto the reactive (011) and (111) surfaces is shown to be characterized by charge transfer from the interacting Fe d-band to the π-system of the thiophene molecule, which causes changes of the intramolecular structure including loss of aromaticity and elongation of the C–S bonds. The thermodynamic and kinetic analysis of the elementary steps involved in the direct desulfurization of thiophene on the reactive FeS surfaces is also presented. Direct desulfurization of thiophene occurs preferentially on the (111) surface, as reflected by the overall exothermic reaction energy calculated for the process (ER = −0.15 eV), with an activation energy of 1.58 eV. PMID:29348782

Calculation and affection of pH value of different desulfurization and dehydration rates in the filling station based on Aspen Plus

NASA Astrophysics Data System (ADS)

Lv, J. X.; Wang, B. F.; Nie, L. H.; Xu, R. R.; Zhou, J. Y.; Hao, Y. J.

2018-01-01

The simulation process of the whole CNG filling station are established using Aspen Plus V7.2. The separator (Sep) was used to simulate the desulfurization and dehydration equipment in the gas station, and the flash module separator Flash 2 was used to simulate the gas storage well with proper temperature and environmental pressure. Furthermore, the sensitivity module was used to analyse the behaviour of the dehydration and desulfurization rate, and the residual pH value of the gas storage wells was between 2.2 and 3.3. The results indicated that the effect of water content on pH value is higher than that of hydrogen sulphide in the environment of gas storage wells, and the calculation process of the pH value is feasible. Additionally, the simulation process provides basic data for the subsequent anticorrosive mechanism and work of gas storage well and has great potential for practical applications.

Expedient synthesis of C-aryl carbohydrates by consecutive biocatalytic benzoin and aldol reactions.

PubMed

Hernández, Karel; Parella, Teodor; Joglar, Jesús; Bujons, Jordi; Pohl, Martina; Clapés, Pere

2015-02-16

The introduction of aromatic residues connected by a C-C bond into the non-reducing end of carbohydrates is highly significant for the development of innovative structures with improved binding affinity and selectivity (e.g., C-aril-sLex). In this work, an expedient asymmetric "de novo" synthetic route to new aryl carbohydrate derivatives based on two sequential stereoselectively biocatalytic carboligation reactions is presented. First, the benzoin reaction of aromatic aldehydes to dimethoxyacetaldehyde is conducted, catalyzed by benzaldehyde lyase from Pseudomonas fluorescens biovar I. Then, the α-hydroxyketones formed are reduced by using NaBH4 yielding the anti diol. After acetal hydrolysis, the aldol addition of dihydroxyacetone, hydroxyacetone, or glycolaldehyde catalyzed by the stereocomplementary D-fructose-6-phosphate aldolase and L-rhamnulose-1-phosphate aldolase is performed. Both aldolases accept unphosphorylated donor substrates, avoiding the need of handling the phosphate group that the dihydroxyacetone phosphate-dependent aldolases require. In this way, 6-C-aryl-L-sorbose, 6-C-aryl-L-fructose, 6-C-aryl-L-tagatose, and 5-C-aryl-L-xylose derivatives are prepared by using this methodology. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

TiO2-Containing Carbon Derived from a Metal-Organic Framework Composite: A Highly Active Catalyst for Oxidative Desulfurization.

PubMed

Bhadra, Biswa Nath; Song, Ji Yoon; Khan, Nazmul Abedin; Jhung, Sung Hwa

2017-09-13

A new metal-organic framework (MOF) composite consisting of Ti- and Zn-based MOFs (ZIF-8(x)@H 2 N-MIL-125; in brief, ZIF(x)@MOF) was designed and synthesized. The pristine MOF [H 2 N-MIL-125 (MOF)]- and an MOF-composite [ZIF(30)@MOF]-derived mesoporous carbons consisting of TiO 2 nanoparticles were prepared by pyrolysis (named MDC-P and MDC-C, respectively). MDC-C showed a higher surface area, larger pore sizes, and larger mesopore volumes than MDC-P. In addition, the TiO 2 nanoparticles on MDC-C have more uniform shapes and sizes and are smaller than those of MDC-P. The obtained MDC-C and MDC-P [together with MOF, ZIF(30)@MOF, pure/nanocrystalline TiO 2 , and activated carbon] were applied in the oxidative desulfurization reaction of dibenzothiophene in a model fuel. The MDC-C, even with a lower TiO 2 content than that of MDC-P, showed an outstanding catalytic performance, especially with a very low catalyst dose (i.e., a very high quantity of dibenzothiophene was converted per unit weight of the catalyst), fast kinetics (∼3 times faster than that for MDC-P), and a low activation energy (lower than that for any reported catalyst) for the oxidation of dibenzothiophene. The large mesopores of MDC-C and the well-dispersed/small TiO 2 might be the dominant factors for the superior catalytic conversions. The oxidative desulfurization of other sulfur-containing organic compounds with various electron densities was also studied with MDC-C to understand the mechanism of catalysis. Moreover, the MDC-C catalyst can be reused many times in the oxidative desulfurization reaction after a simple washing with acetone. Finally, composing MOFs and subsequent pyrolysis is suggested as an effective way to prepare a catalyst with well-dispersed active sites, large pores, and high mesoporosity.

Microbial Desulfurization of a Crude Oil Middle-Distillate Fraction: Analysis of the Extent of Sulfur Removal and the Effect of Removal on Remaining Sulfur

PubMed Central

Grossman, M. J.; Lee, M. K.; Prince, R. C.; Garrett, K. K.; George, G. N.; Pickering, I. J.

1999-01-01

Rhodococcus sp. strain ECRD-1 was evaluated for its ability to desulfurize a 232 to 343°C middle-distillate (diesel range) fraction of Oregon basin (OB) crude oil. OB oil was provided as the sole source of sulfur in batch cultures, and the extent of desulfurization and the chemical fate of the residual sulfur in the oil after treatment were determined. Gas chromatography (GC), flame ionization detection, and GC sulfur chemiluminesce detection analysis were used to qualitatively evaluate the effect of Rhodococcus sp. strain ECRD-1 treatment on the hydrocarbon and sulfur content of the oil, respectively. Total sulfur was determined by combustion of samples and measurement of released sulfur dioxide by infrared absorption. Up to 30% of the total sulfur in the middle distillate cut was removed, and compounds across the entire boiling range of the oil were affected. Sulfur K-edge X-ray absorption-edge spectroscopy was used to examine the chemical state of the sulfur remaining in the treated OB oil. Approximately equal amounts of thiophenic and sulfidic sulfur compounds were removed by ECRD-1 treatment, and over 50% of the sulfur remaining after treatment was in an oxidized form. The presence of partially oxidized sulfur compounds indicates that these compounds were en route to desulfurization. Overall, more than two-thirds of the sulfur had been removed or oxidized by the microbial treatment. PMID:9872778

Three annual flue gas desulfurization gypsum applications on macronutrient and micronutrient losses in runoff from bermudagrass fertilized with poultry litter

USDA-ARS?s Scientific Manuscript database

Considerable amounts of flue gas desulfurization (FGD) gypsum are being produced as a by-product of generating electricity. As a result, beneficial reuse of this by-product is being sought to reduce landfilling and its associated cost. The use of this byproduct as a low-cost soil amendment for suppl...

A non-chemically selective top-down approach towards the preparation of hierarchical TS-1 zeolites with improved oxidative desulfurization catalytic performance.

PubMed

Du, Shuting; Chen, Xiaoxin; Sun, Qiming; Wang, Ning; Jia, Mingjun; Valtchev, Valentin; Yu, Jihong

2016-02-28

Hierarchical TS-1 zeolites with secondary macropores have been successfully prepared by using two different fluoride-containing chemical etching post-treated routes. Hierarchical TS-1 zeolites exhibited a chemical composition similar to that of the parent material and showed remarkably enhanced catalytic activity in oxidative desulfurization reaction.

Overcoming the Gas-Liquid Mass Transfer of Oxygen by Coupling Photosynthetic Water Oxidation with Biocatalytic Oxyfunctionalization.

PubMed

Hoschek, Anna; Bühler, Bruno; Schmid, Andreas

2017-11-20

Gas-liquid mass transfer of gaseous reactants is a major limitation for high space-time yields, especially for O 2 -dependent (bio)catalytic reactions in aqueous solutions. Herein, oxygenic photosynthesis was used for homogeneous O 2 supply via in situ generation in the liquid phase to overcome this limitation. The phototrophic cyanobacterium Synechocystis sp. PCC6803 was engineered to synthesize the alkane monooxygenase AlkBGT from Pseudomonas putida GPo1. With light, but without external addition of O 2 , the chemo- and regioselective hydroxylation of nonanoic acid methyl ester to ω-hydroxynonanoic acid methyl ester was driven by O 2 generated through photosynthetic water oxidation. Photosynthesis also delivered the necessary reduction equivalents to regenerate the Fe 2+ center in AlkB for oxygen transfer to the terminal methyl group. The in situ coupling of oxygenic photosynthesis to O 2 -transferring enzymes now enables the design of fast hydrocarbon oxyfunctionalization reactions. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-Temperature Desulfurization of Heavy Fuel-Derived Reformate Gas Streams for SOFC Applications

NASA Technical Reports Server (NTRS)

Flytzani-Stephanopoulos, Maria; Surgenor, Angela D.

2007-01-01

Desulfurization of the hot reformate gas produced by catalytic partial oxidation or autothermal reforming of heavy fuels, such as JP-8 and jet fuels, is required prior to using the gas in a solid oxide fuel cell (SOFC). Development of suitable sorbent materials involves the identification of sorbents with favorable sulfidation equilibria, good kinetics, and high structural stability and regenerability at the SOFC operating temperatures (650 to 800 C). Over the last two decades, a major barrier to the development of regenerable desulfurization sorbents has been the gradual loss of sorbent performance in cyclic sulfidation and regeneration at such high temperatures. Mixed oxide compositions based on ceria were examined in this work as regenerable sorbents in simulated reformate gas mixtures and temperatures greater than 650 C. Regeneration was carried out with dilute oxygen streams. We have shown that under oxidative regeneration conditions, high regeneration space velocities (greater than 80,000 h(sup -1)) can be used to suppress sulfate formation and shorten the total time required for sorbent regeneration. A major finding of this work is that the surface of ceria and lanthanan sorbents can be sulfided and regenerated completely, independent of the underlying bulk sorbent. This is due to reversible adsorption of H2S on the surface of these sorbents even at temperatures as high as 800 C. La-rich cerium oxide formulations are excellent for application to regenerative H2S removal from reformate gas streams at 650 to 800 C. These results create new opportunities for compact sorber/regenerator reactor designs to meet the requirements of solid oxide fuel cell systems at any scale.

Process for the manufacture of an attrition resistant sorbent used for gas desulfurization

DOEpatents

Venkataramani, Venkat S.; Ayala, Raul E.

2003-09-16

This process produces a sorbent for use in desulfurization of coal gas. A zinc titanate compound and a metal oxide are mixed by milling the compounds in an aqueous medium, the resulting mixture is dried and then calcined, crushed, sleved and formed into pellets for use in a moving-bed reactor. Metal oxides suitable for use as an additive in this process include: magnesium oxide, magnesium oxide plus molybdenum oxide, calcium oxide, yttrium oxide, hafnium oxide, zirconium oxide, cupric oxide, and tin oxide. The resulting sorbent has a percentage of the original zinc or titanium ions substituted for the oxide metal of the chosen additive.

Effect of acyl chain length on selective biocatalytic deacylation on O-aryl glycosides and separation of anomers.

PubMed

Aggarwal, Neha; Arya, Anu; Mathur, Divya; Singh, Sukhdev; Tyagi, Abhilash; Kumar, Rajesh; Rana, Neha; Singh, Rajendra; Prasad, Ashok K

2014-04-01

It has been demonstrated that Lipozyme® TL IM (Thermomyces lanuginosus lipase immobilised on silica) can selectively deacylate the ester function involving the C-5' hydroxyl group of α-anomers over the other acyl functions of anomeric mixture of peracylated O-aryl α,β-D-ribofuranoside. The analysis of results of biocatalytic deacylation reaction revealed that the reaction time decreases with the increase in the acyl chain length from C1 to C4. The unique selectivity of Lipozyme® TL IM has been harnessed for the separation of anomeric mixture of peracylated O-aryl α,β-D-ribofuranosides, The lipase mediated selective deacylation methodology has been used for the synthesis of O-aryl α-D-ribofuranosides and O-aryl β-D-ribofuranosides in pure forms, which can be used as chromogenic substrate for the detection of pathogenic microbial parasites containing glycosidases. Copyright © 2014. Published by Elsevier Inc.

Highly efficient extraction and oxidative desulfurization system using Na7H2LaW10O36⋅32 H2O in [bmim]BF4 at room temperature.

PubMed

Xu, Junhua; Zhao, Shen; Chen, Wei; Wang, Miao; Song, Yu-Fei

2012-04-10

Highly efficient, deep desulfurization of model oil containing dibenzothiophene (DBT), benzothiophene (BT), or 4,6-dimethyldibenzothiophene (4,6-DMDBT) has been achieved under mild conditions by using an extraction and catalytic oxidative desulfurization system (ECODS) in which a lanthanide-containing polyoxometalate Na(7)H(2)LnW(10)O(36)⋅32 H(2)O (LnW(10); Ln = Eu, La) acts as catalyst, [bmim]BF(4) (bmim = 1-butyl-3-methylimidazolium) as extractant, and H(2)O(2) as oxidant. Sulfur removal follows the order DBT>4,6-DMDBT>BT at 30 °C. DBT can be completely oxidized to the corresponding sulfone in 25 min under mild conditions, and the LaW(10)/[bmim]BF(4) system could be recycled for ten times with only slight decrease in activity. Thus, LaW(10) in [bmim]BF(4) is one of the most efficient systems for desulfurization using ionic liquids as extractant reported so far. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Integrated Mg/TiO2-ionic liquid system for deep desulfurization

NASA Astrophysics Data System (ADS)

Yin, Yee Cia; Kait, Chong Fai; Fatimah, Hayyiratul; Wilfred, Cecilia

2014-10-01

A series of Mg/TiO2 photocatalysts were prepared using wet impregnation method followed by calcination at 300, 400 and 500°C for 1 h. The photocatalysts were characterized using Thermal Gravimetric Analysis, Fourier-Transform Infrared Spectroscopy, X-Ray Diffraction, and Field Emission Scanning Electron Microscopy. The performance for deep desulfurization was investigated using model oil with 100 ppm sulfur (in the form of dibenzothiophene). The integrated system involves photocatalytic oxidation followed by ionic liquid-extraction processes. The best performing photocatalyst was 0.25wt% Mg loaded on titania calcined at 400°C (0.25Mg400), giving 98.5% conversion of dibenzothiophene to dibenzothiophene sulfone. The highest extraction efficiency of 97.8% was displayed by 1,2-diethylimidazolium diethylphosphate. The overall total sulfur removal was 96.3%.

Novel dry-desulfurization process using Ca(OH)2/fly ash sorbent in a circulating fluidized bed.

PubMed

Matsushima, Norihiko; Li, Yan; Nishioka, Masateru; Sadakata, Masayoshi; Qi, Haiying; Xu, Xuchang

2004-12-15

A dry-desulfurization process using Ca(OH)2/fly ash sorbent and a circulating fluidized bed (CFB) was developed. Its aim was to achieve high SO2 removal efficiency without humidification and production of CaSO4 as the main byproduct. The CaSO4 produced could be used to treat alkalized soil. An 83% SO2 removal rate was demonstrated, and a byproduct with a high CaSO4 content was produced through baghouse ash. These results indicated that this process could remove SO2 in flue gas with a high efficiency under dry conditions and simultaneously produce soil amendment. It was shown that NO and NO2 enhanced the SO2 removal rate markedly and that NO2 increased the amount of CaSO4 in the final product more than NO. These results confirmed that the significant effects of NO and NO2 on the SO2 removal rate were due to chain reactions that occurred under favorable conditions. The amount of baghouse ash produced increased as the reaction progressed, indicating that discharge of unreacted Ca(OH)2 from the reactor was suppressed. Hence, unreacted Ca(OH)2 had a long residence time in the CFB, resulting in a high SO2 removal rate. It was also found that 350 degrees C is the optimum reaction temperature for dry desulfurization in the range tested (320-380 degrees C).

Reactions of VX, HD, and their simulants with NaY and AgY zeolites. Desulfurization of VX on AgY

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

Wagner, G.W.; Bartram, P.W.

1999-11-09

The room-temperature reactions of the chemical warfare agents VX (O-ethyl S-2-(diisopropylamino)-ethyl methylphosphonothioate), HD (2,2{prime}-dichloroethyl sulfide, or mustard), and their common simulants, O,S-diethyl phenylphosphonothioate (DEPPT) and 2-chloroethyl phenyl sulfide (CEPS), with NaY and silver-exchanged (AgY) zeolites have been studied using solid-state magic angle spinning NMR. VX hydrolyzes via exclusive cleavage of the P{single{underscore}bond}S bond on both NaY and AgY to yield ethyl methylphosphonate (EMPA). The reaction is significantly faster on AgY than on NaY, suggesting catalysis by silver. On AgY, an intermediate silver salt of EMPA is apparently formed which is slowly converted to ethyl 2-(diisopropylamino)ethyl methylphosphonate (QB, the desulfurized analoguemore » of VX) in about a 78% yield. DEPPT similarly hydrolyzes via P{single{underscore}bond}S cleavage on AgY to yield an apparent silver salt of ethyl phenylphosphonate, which does not undergo further reaction to the desulfurized analogue. No reaction is observed for DEPPT on NaY. HD on AgY forms both vinyl sulfide and the cyclic ether 1,4-thioxane. HD reacts faster on NaY to exclusively form the CH-TG sulfonium ion (HOCH{sub 2}CH{sub 2}SCH{sub 2}CH{sub 2}S{sup +}[CH{sub 2}CH{sub 2}OH]{sub 2}). CEPS also reacts faster on NaY, forming 2-hydroxyethyl phenyl sulfide. On AgY, CEPS does not give the vinyl product, but does yield the ether product PhSCH{sub 2}CH{sub 2}OCH{sub 2}CH{sub 2}SPh. A mechanism is proposed for the silver-catalyzed hydrolysis of VX, the desulfurization of the cleaved thiol, and the formation of QB.« less

Biocatalytic Production of Trehalose from Maltose by Using Whole Cells of Permeabilized Recombinant Escherichia coli

PubMed Central

Sun, Ye; Mei, Wending; Ouyang, Jia

2015-01-01

Trehalose is a non-reducing disaccharide, which can protect proteins, lipid membranes, and cells from desiccation, refrigeration, dehydration, and other harsh environments. Trehalose can be produced by different pathways and trehalose synthase pathway is a convenient, practical, and low-cost pathway for the industrial production of trehalose. In this study, 3 candidate treS genes were screened from genomic databases of Pseudomonas and expressed in Escherichia coli. One of them from P. stutzeri A1501 exhibited the best transformation ability from maltose into trehalose and the least byproduct. Thus, whole cells of this recombinant E. coli were used as biocatalyst for trehalose production. In order to improve the conversion rate of maltose to trehalose, optimization of the permeabilization and biotransformation were carried out. Under optimal conditions, 92.2 g/l trehalose was produced with a high productivity of 23.1 g/(l h). No increase of glucose was detected during the whole course. The biocatalytic process developed in this study might serve as a candidate for the large scale production of trehalose. PMID:26462117

Application of iterative robust model-based optimal experimental design for the calibration of biocatalytic models.

PubMed

Van Daele, Timothy; Gernaey, Krist V; Ringborg, Rolf H; Börner, Tim; Heintz, Søren; Van Hauwermeiren, Daan; Grey, Carl; Krühne, Ulrich; Adlercreutz, Patrick; Nopens, Ingmar

2017-09-01

The aim of model calibration is to estimate unique parameter values from available experimental data, here applied to a biocatalytic process. The traditional approach of first gathering data followed by performing a model calibration is inefficient, since the information gathered during experimentation is not actively used to optimize the experimental design. By applying an iterative robust model-based optimal experimental design, the limited amount of data collected is used to design additional informative experiments. The algorithm is used here to calibrate the initial reaction rate of an ω-transaminase catalyzed reaction in a more accurate way. The parameter confidence region estimated from the Fisher Information Matrix is compared with the likelihood confidence region, which is not only more accurate but also a computationally more expensive method. As a result, an important deviation between both approaches is found, confirming that linearization methods should be applied with care for nonlinear models. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1278-1293, 2017. © 2017 American Institute of Chemical Engineers.

Antagonistic Enzymes in a Biocatalytic pH Feedback System Program Autonomous DNA Hydrogel Life Cycles.

PubMed

Heinen, Laura; Heuser, Thomas; Steinschulte, Alexander; Walther, Andreas

2017-08-09

Enzymes regulate complex functions and active behavior in natural systems and have shown increasing prospect for developing self-regulating soft matter systems. Striving for advanced autonomous hydrogel materials with fully programmable, self-regulated life cycles, we combine two enzymes with an antagonistic pH-modulating effect in a feedback-controlled biocatalytic reaction network (BRN) and couple it to pH-responsive DNA hydrogels to realize hydrogel systems with distinct preprogrammable lag times and lifetimes in closed systems. The BRN enables precise and orthogonal internal temporal control of the "ON" and "OFF" switching times of the temporary gel state by modulation of programmable, nonlinear pH changes. The time scales are tunable by variation of the enzyme concentrations and additional buffer substances. The resulting material system operates in full autonomy after injection of the chemical fuels driving the BRN. The concept may open new applications inherent to DNA hydrogels, for instance, autonomous shape memory behavior for soft robotics. We further foresee general applicability to achieve autonomous life cycles in other pH switchable systems.

Integrated lipase production and in situ biodiesel synthesis in a recombinant Pichia pastoris yeast: an efficient dual biocatalytic system composed of cell free enzymes and whole cell catalysts

PubMed Central

2014-01-01

Background Lipase-catalyzed biotransformation of acylglycerides or fatty acids into biodiesel via immobilized enzymes or whole cell catalysts has been considered as one of the most promising methods to produce renewable and environmentally friendly alternative liquid fuels, thus being extensively studied so far. In all previously pursued approaches, however, lipase enzymes are prepared in an independent process separated from enzymatic biodiesel production, which would unavoidably increase the cost and energy consumption during industrial manufacture of this cost-sensitive energy product. Therefore, there is an urgent need to develop novel cost-effective biocatalysts and biocatalytic processes with genuine industrial feasibility. Result Inspired by the consolidated bioprocessing of lignocellulose to generate bioethanol, an integrated process with coupled lipase production and in situ biodiesel synthesis in a recombinant P. pastoris yeast was developed in this study. The novel and efficient dual biocatalytic system based on Thermomyces lanuginosus lipase took advantage of both cell free enzymes and whole cell catalysts. The extracellular and intracellular lipases of growing yeast cells were simultaneously utilized to produce biodiesel from waste cooking oils in situ and in one pot. This integrated system effectively achieved 58% and 72% biodiesel yield via concurrent esterified-transesterified methanolysis and stepwise hydrolysis-esterification at 3:1 molar ratio between methanol and waste cooking oils, respectively. Further increasing the molar ratio of methanol to waste cooking oils to 6:1 led to an 87% biodiesel yield using the stepwise strategy. Both water tolerance and methanol tolerance of this novel system were found to be significantly improved compared to previous non-integrated biodiesel production processes using separately prepared immobilized enzymes or whole cell catalysts. Conclusion We have proposed a new concept of integrated biodiesel production

PET-modified red mud as catalysts for oxidative desulfurization reactions.

PubMed

do Prado, Nayara T; Heitmann, Ana P; Mansur, Herman S; Mansur, Alexandra A; Oliveira, Luiz C A; de Castro, Cinthia S

2017-07-01

This work describes the synthesis of catalysts based on red mud/polyethylene terephthalate (PET) composites and their subsequent heat treatment under N 2 atmosphere. The materials were characterized by scanning electron microscopy (SEM), temperature programmed reduction (TPR), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric (TG) analysis and N 2 adsorption/desorption. The catalysts were evaluated in the oxidative desulfurization reaction of dibenzothiophene (DBT) in a biphasic system. The results indicated that the PET impregnation on red mud increased the affinity of the catalyst with the nonpolar phase (fuel), in which the contaminant was dissolved, allowing a higher conversion (up to 80%) and selectivity to the corresponding dibenzothiophene sulfone. The sulfone compound is more polar than DBT and diffused into the polar solvent as indicated by the data obtained via gas chromatography-mass spectrometry (GC-MS). Copyright © 2017. Published by Elsevier B.V.

Tests on a pilot plant for reheating desulfurized flue gases with the help of heat pipes

NASA Astrophysics Data System (ADS)

Schug, W.

1982-02-01

Desulfurized flue gases were reheated with a heat pipe heat exchanger. Finned heat pipes, with a coating or made of high quality steel were subjected to different operating conditions for 1000 hr. The coating proved to be unsuitable for heat transfer because it swells and detaches itself from the background material. The high quality steels showed pitting and surface corrosion. The possibilities of cleaning were also studied to prevent deposits forming on the heat pipes, but no solution was found.

Derivatization of single-walled carbon nanotubes with redox mediator for biocatalytic oxygen electrodes.

PubMed

Sadowska, K; Stolarczyk, K; Biernat, J F; Roberts, K P; Rogalski, J; Bilewicz, R

2010-11-01

Single-walled carbon nanotubes (SWCNTs) were covalently modified with a redox mediator derived from 2,2'-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS), and implemented in the construction of electrodes for biocatalytic oxygen reduction. The procedure is based on: covalent bonding of mediator to nanotubes, placing the nanotubes directly on the carbon electrode surface and covering the nanostructured electrode with a Nafion film containing laccase as the biocatalyst. The modified electrode is stable and the problem of mediator (ABTS) leaking from the film is eliminated by binding it covalently to the nanotubes. Three different synthetic approaches were used to obtain ABTS-modified carbon nanotubes. Nanotubes were modified at ends/defect sites or on the nanotube sidewalls and characterized by Raman spectroscopy, TGA and electrochemistry. The accessibility of differently located ABTS units by the laccase active center and mediation of electron transfer were studied by cyclic voltammetry. The surface concentrations of ABTS groups electrically connected with the electrode were compared for each of the electrodes based on the charges of the voltammetric peaks recorded in the deaerated solution. The nanotube modification procedure giving the best parameters of the catalytic process was selected. Copyright © 2010 Elsevier B.V. All rights reserved.

Application of Two Cobalt-Based Metal-Organic Frameworks as Oxidative Desulfurization Catalysts.

PubMed

Masoomi, Mohammad Yaser; Bagheri, Minoo; Morsali, Ali

2015-12-07

Two new porous cobalt-based metal-organic frameworks, [Co6(oba)5(OH)2(H2O)2(DMF)4]n · 5DMF (TMU-10) and [Co3(oba)3(O) (Py)0.5] n · 4DMF · Py (TMU-12) have been synthesized by solvothermal method using a nonlinear dicarboxylate ligand. Under mild reaction conditions, these compounds exhibited good catalytic activity and reusability in oxidative desulfurization (ODS) reaction of model oil which was prepared by dissolving dibenzothiophene (DBT) in n-hexane. FT-IR and Mass analysis showed that the main product of DBT oxidation is its corresponding sulfone, which was adsorbed on the surfaces of catalysts. The activation energy was obtained as 13.4 kJ/mol.

Selective desulfurization of cysteine in the presence of Cys(Acm) in polypeptides obtained by native chemical ligation.

PubMed

Pentelute, Brad L; Kent, Stephen B H

2007-02-15

Increased versatility for the synthesis of proteins and peptides by native chemical ligation requires the ability to ligate at positions other than Cys. Here, we report that Raney nickel can be used under standard conditions for the selective desulfurization of Cys in the presence of Cys(Acm). This simple and practical tactic enables the more common Xaa-Ala junctions to be used as ligation sites for the chemical synthesis of Cys-containing peptides and proteins. [reaction: see text].

Characterization of a flavin reductase from a thermophilic dibenzothiophene-desulfurizing bacterium, Bacillus subtilis WU-S2B.

PubMed

Takahashi, Shusuke; Furuya, Toshiki; Ishii, Yoshitaka; Kino, Kuniki; Kirimura, Kohtaro

2009-01-01

Bacillus subtilis WU-S2B is a thermophilic dibenzothiophene (DBT)-desulfurizing bacterium and produces a flavin reductase (Frb) that couples with DBT and DBT sulfone monooxygenases. The recombinant Frb was purified from Escherichia coli cells expressing the frb gene and was characterized. The purified Frb exhibited high stability over wide temperature and pH ranges of 20-55 degrees C and 2-12, respectively. Frb contained FMN and exhibited both flavin reductase and nitroreductase activities.

Indium-Catalyzed Reductive Dithioacetalization of Carboxylic Acids with Dithiols: Scope, Limitations, and Application to Oxidative Desulfurization.

PubMed

Nishino, Kota; Minato, Kohei; Miyazaki, Takahiro; Ogiwara, Yohei; Sakai, Norio

2017-04-07

In this study an InI 3 -TMDS (1,1,3,3-tetramethyldisiloxane) reducing system effectively catalyzed the reductive dithioacetalization of a variety of aromatic and aliphatic carboxylic acids with 1,2-ethanedithiol or 1,3-propanedithiol leading to the one-pot preparation of either 1,3-dithiolane derivatives or a 1,3-dithiane derivative. Also, the intact indium catalyst continuously catalyzed the subsequent oxidative desulfurization of an in situ formed 1,3-dithiolane derivative, which led to the preparation of the corresponding aldehydes.

Synthesis of mesoporous TS-1 using a hybrid SiO{sub 2}–TiO{sub 2} xerogel for catalytic oxidative desulfurization

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

Yang, Seung-Tae; Jeong, Kwang-Eun; Jeong, Soon-Yong

2012-12-15

Graphical abstract: Display Omitted Highlights: ► Meso-TS-1 catalyst was synthesized using a SiO{sub 2}–TiO{sub 2} xerogel with an organosilane precursor. ► Hierarchical pore structure was confirmed by characterization of the materials. ► Catalytic activity was tested using oxidative desulfurization of the model sulfur compounds. ► Meso-TS-1 demonstrated significantly improved catalytic activity than TS-1. -- Abstract: Mesoporous TS-1 (M-TS-1) was synthesized using a hybrid SiO{sub 2}–TiO{sub 2} xerogel combined with an organosilane precursor. Prepared samples were characterized by XRD, UV–vis spectroscopy, SEM, and N{sub 2} adsorption–desorption measurement. M-TS-1, prepared in 2 days, showed high crystallinity and the best textural properties amongmore » the samples. The N{sub 2} adsorption–desorption isotherms of M-TS-1 exhibited a hysteresis loop at pressure higher than P/P{sub 0} = 0.4, clearly indicating the existence of mesopores. M-TS-1 has significantly larger mesopore volume (0.48 cm{sup 3}/g) than that of conventional TS-1 (0.07 cm{sup 3}/g), and showed a narrow peak centered at ca. 6.3 nm. In the oxidative desulfurization reaction, M-TS-1 was more active than conventional TS-1 at the same Ti-loading; M-TS-1 produced a dibenzothiophene (DBT) conversion of 96%, whereas conventional TS-1 produced a final DBT conversion of 5.6% after a reaction time of 180 min. Oxidative desulfurization over TS-1 was influenced both by electron density and steric hindrance in the sulfur compounds tested.« less

Efficient H2O2/CH3COOH oxidative desulfurization/denitrification of liquid fuels in sonochemical flow-reactors.

PubMed

Calcio Gaudino, Emanuela; Carnaroglio, Diego; Boffa, Luisa; Cravotto, Giancarlo; Moreira, Elizabeth M; Nunes, Matheus A G; Dressler, Valderi L; Flores, Erico M M

2014-01-01

The oxidative desulfurization/denitrification of liquid fuels has been widely investigated as an alternative or complement to common catalytic hydrorefining. In this process, all oxidation reactions occur in the heterogeneous phase (the oil and the polar phase containing the oxidant) and therefore the optimization of mass and heat transfer is of crucial importance to enhancing the oxidation rate. This goal can be achieved by performing the reaction in suitable ultrasound (US) reactors. In fact, flow and loop US reactors stand out above classic batch US reactors thanks to their greater efficiency and flexibility as well as lower energy consumption. This paper describes an efficient sonochemical oxidation with H2O2/CH3COOH at flow rates ranging from 60 to 800 ml/min of both a model compound, dibenzotiophene (DBT), and of a mild hydro-treated diesel feedstock. Four different commercially available US loop reactors (single and multi-probe) were tested, two of which were developed in the authors' laboratory. Full DBT oxidation and efficient diesel feedstock desulfurization/denitrification were observed after the separation of the polar oxidized S/N-containing compounds (S≤5 ppmw, N≤1 ppmw). Our studies confirm that high-throughput US applications benefit greatly from flow-reactors. Copyright © 2013 Elsevier B.V. All rights reserved.

Producing ammonium sulfate from flue gas desulfurization by-products

USGS Publications Warehouse

Chou, I.-Ming; Bruinius, J.A.; Benig, V.; Chou, S.-F.J.; Carty, R.H.

2005-01-01

Emission control technologies using flue gas desulfurization (FGD) have been widely adopted by utilities burning high-sulfur fuels. However, these technologies require additional equipment, greater operating expenses, and increased costs for landfill disposal of the solid by-products produced. The financial burdens would be reduced if successful high-volume commercial applications of the FGD solid by-products were developed. In this study, the technical feasibility of producing ammonium sulfate from FGD residues by allowing it to react with ammonium carbonate in an aqueous solution was preliminarily assessed. Reaction temperatures of 60, 70, and 80??C and residence times of 4 and 6 hours were tested to determine the optimal conversion condition and final product evaluations. High yields (up to 83%) of ammonium sulfate with up to 99% purity were achieved under relatively mild conditions. The optimal conversion condition was observed at 60??C and a 4-hour residence time. The results of this study indicate the technical feasibility of producing ammonium sulfate fertilizer from an FGD by-product. Copyright ?? Taylor & Francis Inc.

Removal of hazardous gaseous pollutants from industrial flue gases by a novel multi-stage fluidized bed desulfurizer.

PubMed

Mohanty, C R; Adapala, Sivaji; Meikap, B C

2009-06-15

Sulfur dioxide and other sulfur compounds are generated as primary pollutants from the major industries such as sulfuric acid plants, cupper smelters, catalytic cracking units, etc. and cause acid rain. To remove the SO(2) from waste flue gas a three-stage counter-current multi-stage fluidized bed adsorber was developed as desulfurization equipment and operated in continuous bubbling fluidization regime for the two-phase system. This paper represents the desulfurization of gas mixtures by chemical sorption of sulfur dioxide on porous granular calcium oxide particles in the reactor at ambient temperature. The advantages of the multi-stage fluidized bed reactor are of high mass transfer and high gas-solid residence time that can enhance the removal of acid gas at low temperature by dry method. Experiments were carried out in the bubbling fluidization regime supported by visual observation. The effects of the operating parameters such as sorbent (lime) flow rate, superficial gas velocity, and the weir height on SO(2) removal efficiency in the multistage fluidized bed are reported. The results have indicated that the removal efficiency of the sulfur dioxide was found to be 65% at high solid flow rate (2.0 kg/h) corresponding to lower gas velocity (0.265 m/s), wier height of 70 mm and SO(2) concentration of 500 ppm at room temperature.

Survey of flue gas desulfurization systems: Hawthorn Station, Kansas City Power and Light Co. Final report

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

Isaacs, G.A.; Zada, F.K.

1975-09-01

Results are given of a survey of the flue gas desulfurization (FGD) systems at Kansas City Power and Light Co.'s Hawthorn Power Station. The FGD systems on Hawthorn boilers 3 and 4 were designed to operate by injection of dry limestone in the boiler's furnace, followed by tail gas scrubbing. Because of tube plugging in boiler 4 the mode of operation of the FGD system on that boiler was modified: ground limestone is now introduced into the flue gas near the gas inlet to the scrubber tower. (GRA)

Method for reducing sulfate formation during regeneration of hot-gas desulfurization sorbents

DOEpatents

Bissett, Larry A.; Strickland, Larry D.; Rockey, John M.

1994-01-01

The regeneration of sulfur sorbents having sulfate forming tendencies and used for desulfurizing hot product gas streams such as provided by coal gasification is provided by employing a two-stage regeneration method. Air containing a sub-stoichiometric quantity of oxygen is used in the first stage for substantially fully regenerating the sorbent without sulfate formation and then regeneration of the resulting partially regenerated sorbent is completed in the second stage with air containing a quantity of oxygen slightly greater than the stoichiometric amount adequate to essentially fully regenerate the sorbent. Sulfate formation occurs in only the second stage with the extent of sulfate formation being limited only to the portion of the sulfur species contained by the sorbent after substantially all of the sulfur species have been removed therefrom in the first stage.

Copper-catalyzed oxidative desulfurization-oxygenation of thiocarbonyl compounds using molecular oxygen: an efficient method for the preparation of oxygen isotopically labeled carbonyl compounds.

PubMed

Shibahara, Fumitoshi; Suenami, Aiko; Yoshida, Atsunori; Murai, Toshiaki

2007-06-21

A novel copper-catalyzed oxidative desulfurization reaction of thiocarbonyl compounds, using molecular oxygen as an oxidant and leading to formation of carbonyl compounds, has been developed, and the utility of the process is demonstrated by its application to the preparation of a carbonyl-18O labeled sialic acid derivative.

Species Differences in the Oxidative Desulfurization of a Thiouracil-Based Irreversible Myeloperoxidase Inactivator by Flavin-Containing Monooxygenase Enzymes.

PubMed

Eng, Heather; Sharma, Raman; Wolford, Angela; Di, Li; Ruggeri, Roger B; Buckbinder, Leonard; Conn, Edward L; Dalvie, Deepak K; Kalgutkar, Amit S

2016-08-01

N1-Substituted-6-arylthiouracils, represented by compound 1 [6-(2,4-dimethoxyphenyl)-1-(2-hydroxyethyl)-2-thioxo-2,3-dihydropyrimidin-4(1H)-one], are a novel class of selective irreversible inhibitors of human myeloperoxidase. The present account is a summary of our in vitro studies on the facile oxidative desulfurization in compound 1 to a cyclic ether metabolite M1 [5-(2,4-dimethoxyphenyl)-2,3-dihydro-7H-oxazolo[3,2-a]pyrimidin-7-one] in NADPH-supplemented rats (t1/2 [half-life = mean ± S.D.] = 8.6 ± 0.4 minutes) and dog liver microsomes (t1/2 = 11.2 ± 0.4 minutes), but not in human liver microsomes (t1/2 > 120 minutes). The in vitro metabolic instability also manifested in moderate-to-high plasma clearances of the parent compound in rats and dogs with significant concentrations of M1 detected in circulation. Mild heat deactivation of liver microsomes or coincubation with the flavin-containing monooxygenase (FMO) inhibitor imipramine significantly diminished M1 formation. In contrast, oxidative metabolism of compound 1 to M1 was not inhibited by the pan cytochrome P450 inactivator 1-aminobenzotriazole. Incubations with recombinant FMO isoforms (FMO1, FMO3, and FMO5) revealed that FMO1 principally catalyzed the conversion of compound 1 to M1. FMO1 is not expressed in adult human liver, which rationalizes the species difference in oxidative desulfurization. Oxidation by FMO1 followed Michaelis-Menten kinetics with Michaelis-Menten constant, maximum rate of oxidative desulfurization, and intrinsic clearance values of 209 μM, 20.4 nmol/min/mg protein, and 82.7 μl/min/mg protein, respectively. Addition of excess glutathione essentially eliminated the conversion of compound 1 to M1 in NADPH-supplemented rat and dog liver microsomes, which suggests that the initial FMO1-mediated S-oxygenation of compound 1 yields a sulfenic acid intermediate capable of redox cycling to the parent compound in a glutathione-dependent fashion or undergoing further oxidation to a more

Synthesis of geminal difluorides by oxidative desulfurization-difluorination of alkyl aryl thioethers with halonium electrophiles in the presence of fluorinating reagents and its application for 18F-radiolabeling.

PubMed

Hugenberg, Verena; Wagner, Stefan; Kopka, Klaus; Schober, Otmar; Schäfers, Michael; Haufe, Günter

2010-09-17

Various ω-substituted 1,1-difluoroalkanes are synthesized in good yields from alkyl aryl thioethers by a new oxidative desulfurization-difluorination protocol with the reagents combination of 1,3-dibromo-5,5-dimethylhydantoin (DBH) as an oxidizer and pyridine·9HF (Py·9HF) as a fluoride source. The reaction proceeds via a fluoro-Pummerer-type rearrangement followed by an oxidative desulfurization-fluorination step. Starting from α-fluorinated thioethers, this reaction is promising for (18)F-labeling (τ(1/2) = 110 min) of ligands applicable for positron emission tomography (PET). Using the combination of DBH and carrier-added Py·9H[(18)F]F, an (18)F-labeled difluoride was synthesized from the corresponding α-fluoro thioether with a radiochemical yield of 9%.

Major study reveals EEC gas oil desulfurization costs

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

Waller, G.J.; Conrad, M.C.; Cremer, G.

1985-01-21

The interest of the European Economic Community (EEC) Commission in the issue of acid rain has prompted a Concawe working group to make an independent study of the cost of achieving a reduction of average sulfur levels for gas oils consumed in the EEC. The need for desulfurization of gas oils should be seen in the context of their overall contribution to SO/sub 2/ emissions. The removal of sulfur from gas oil is apparently one of the most costly ways to reduce SO/sub 2/ emissions. The overall effect is apparently the smallest. A reduction of 0.1% sulfur for all gasmore » oil produced in the EEC would result in a reduction of only about 140,000 tons/year of sulfur, corresponding to less than 2% of the present total SO/sub 2/ emissions. The cost of the incremental ton of sulfur removed from the gas oil pool increases significantly for lower sulfur specifications. The overall conclusion is that sulfur reduction between 0.43% and 0.2% is comparable in cost to other methods of reducing SO/sub 2/ emissions. For a reduction below 0.2%, excessive costs can be expected and it would be more economical in most cases to consider another means.« less

Preparation of MoO2/g-C3N4 composites with a high surface area and its application in deep desulfurization from model oil

NASA Astrophysics Data System (ADS)

Hou, Liang-pei; Zhao, Rong-xiang; Li, Xiu-ping; Gao, Xiao-han

2018-03-01

A series of catalysts of composition X-MoO2/g-C3N4 (X = 0, 0.5, 1, 3, 5 wt.%) were successfully synthesized by calcination of a mixture of (NH4)6Mo7O24·4H2O and g-C3N4. Oxidative desulfurization experiments were conducted using X-MoO2/g-C3N4 as a catalyst, H2O2 as an oxidant, and ionic liquids (ILs) as extraction agents. Catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FT-IR), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), and Brunauer-Emmett-Teller analysis (BET). Characterization results suggested that MoO2 was present in the catalyst and its crystallinity improved with increased Mo-loading. The catalysts had a larger specific surface area due to the presence of MoO2 dispersed on g-C3N4. Experimental results showed that 3%-MoO2/g-C3N4 had the highest catalytic activity among all the catalysts tested. A desulfurization rate of 96.0% was achieved under optimal conditions. Through gas chromatography-mass spectrometry (GC-MS) analysis, it was shown that dibenzothoiphene sulfone was the sole product of the oxidation desulfurization reaction. An apparent activation energy of 61.1 kJ/mol was estimated based on Arrhenius equation. The activity of 3%-MoO2/g-C3N4 slightly decreased after six runs. A possible mechanism for the reaction has been proposed.

Recovery of SO2 and MgO from By-Products of MgO Wet Flue Gas Desulfurization.

PubMed

Yan, Liyun; Lu, Xiaofeng; Wang, Quanhai; Guo, Qiang

2014-11-01

An industrial demonstration unit using natural gas as a heat source was built to calcine the by-products of MgO wet flue gas desulfurization from power plants; influencing factors on the SO 2 content in calciner gas were comprehensively analyzed; and an advantageous recycling condition of MgO and SO 2 from by-products was summarized. Results showed that the SO 2 content in the calciner gas was increased by more than 10 times under a lower excess air coefficient, a higher feed rate, a lower crystal water in by-products, and a higher feed port position. For the tests conducted under the excess air coefficient above and below one, the effect of the furnace temperature on the SO 2 content in the calciner gas was reversed. Results of activity analysis indicate that particles of MgO generated under the calcination temperature of 900-1,000°C had a high activity. In contrast, due to the slight sintering, MgO generated under the calcination temperature of 1,100°C had a low activity. To recycle SO 2 as well as MgO, a temperature range of 900-927°C for TE103 is proposed. These studies will prompt the desulfurization market diversification, reduce the sulfur's dependence on imports for making sulfuric acid, be meaningful to balance the usage of the natural resource in China, and be regarded as a reference for the development of this technology for other similar developing countries.

GeoChip-based analysis of the microbial community functional structures in simultaneous desulfurization and denitrification process.

PubMed

Yu, Hao; Chen, Chuan; Ma, Jincai; Liu, Wenzong; Zhou, Jizhong; Lee, Duu-Jong; Ren, Nanqi; Wang, Aijie

2014-07-01

The elemental sulfur (S°) recovery was evaluated in the presence of nitrate in two development models of simultaneous desulfurization and denitrification (SDD) process. At the loading rates of 0.9 kg S/(m³·day) for sulfide and 0.4 kg N/(m³·day) for nitrate, S° conversion rate was 91.1% in denitrifying sulfide removal (DSR) model which was higher than in integrated simultaneous desulfurization and denitrification (ISDD) model (25.6%). A comprehensive analysis of functional diversity, structure and metabolic potential of microbial communities was examined in two models by using functional gene array (GeoChip 2.0). GeoChip data indicated that diversity indices, community structure, and abundance of functional genes were distinct between two models. Diversity indices (Simpson's diversity index (1/D) and Shannon-Weaver index (H')) of all detected genes showed that with elevated influent loading rate, the functional diversity decreased in ISDD model but increased in DSR model. In contrast to ISDD model, the overall abundance of dsr genes was lower in DSR model, while some functional genes targeting from nitrate-reducing sulfide-oxidizing bacteria (NR-SOB), such as Thiobacillus denitrificans, Sulfurimonas denitrificans, and Paracoccus pantotrophus were more abundant in DSR model which were highly associated with the change of S(0) conversion rate obtained in two models. The results obtained in this study provide additional insights into the microbial metabolic mechanisms involved in ISDD and DSR models, which in turn will improve the overall performance of SDD process. Copyright © 2014. Published by Elsevier B.V.

Biocatalytic Desulfurization Capabilities of a Mixed Culture during Non-Destructive Utilization of Recalcitrant Organosulfur Compounds

PubMed Central

Ismail, Wael; El-Sayed, Wael S.; Abdul Raheem, Abdul Salam; Mohamed, Magdy E.; El Nayal, Ashraf M.

2016-01-01

We investigated the biodesulfurization potential of a mixed culture AK6 enriched from petroleum hydrocarbons-polluted soil with dibenzothiophene (DBT) as a sulfur source. In addition to DBT, AK6 utilized the following compounds as sulfur sources: 4-methyldibenzothiophene (4-MDBT), benzothiophene (BT), and 4,6- dimethyldibenzothiophene (4,6-DM-DBT). None of these compounds supported the growth of AK6 as the sole carbon and sulfur source. AK6 could not grow on dibenzylsulfide (DBS) as a sulfur source. The AK6 community structure changed according to the provided sulfur source. The major DGGE bands represented members of the genera Sphingobacterium, Klebsiella, Pseudomonas, Stenotrophomonas, Arthrobacter, Mycobacterium, and Rhodococcus. Sphingobacterium sp. and Pseudomonas sp. were abundant across all cultures utilizing any of the tested thiophenic S-compounds. Mycobacterium/Rhodococcus spp. were restricted to the 4-MDBT culture. The 4-MDBT culture had the highest species richness and diversity. Biodesulfurization of DBT by resting cells of AK6 produced 2-hydroxybiphenyl (2-HBP) in addition to trace amounts of phenylacetate. AK6 transformed DBT to 2-hydroxybiphenyl with a specific activity of 9 ± 0.6 μM 2-HBP g dry cell weight−1 h−1. PCR confirmed the presence in the AK6 community of the sulfur-specific (4S) pathway genes dszB and dszC. Mixed cultures hold a better potential than axenic ones for the development of a biodesulfurization technology. PMID:26973637

Guidelines for the use of fiberglass reinforced plastic in utility FGD systems. [Flue gas desulfurization (FGD); contains glossary

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

Rapoza, R.J.; Vollmer, H.R.; Haberly, K.L.

1992-11-01

Fiberglass reinforced plastic (FRP) materials offer excellent corrosion-resistant properties and long-term cost advantages compared to exotic alloys or organic lining systems. This guideline document provides potential buyers of FRP FGD (flue gas desulfurization) equipment with enough knowledge of FRP materials and methods to make informed decisions when procuring FRP equipment or services. It is divided into the following chapters: application criteria, procurement strategies, FRP basics, guidelines for designing FRP equipment, quality management. A glossary and manufacturers information/recommendations are included.

Simultaneous desulfurization and denitrification of flue gas by ·OH radicals produced from O2+ and water vapor in a duct.

PubMed

Bai, Mindi; Zhang, Zhitao; Bai, Mindong

2012-09-18

In the present study, simultaneous flue gas desulfurization and denitrification are achieved with ·OH radicals generated from O(2)(+) reacting with water vapor in a duct. The O(2)(+) ions are generated by a strong ionization dielectric barrier discharge and then injected into the duct. Compared with conventional gas discharge treatment, the present method does not need a plasma reaction reactor, additional catalysts, reductants, or oxidants. The main recovered products are the liquids H(2)SO(4) and HNO(3), which can be used in many processes. Removal rates of 97% for NO and 82% for SO(2) are obtained under the following optimal experimental conditions: molar ratio of reactive oxygen species (O(2)(+), O(3)) to SO(2) and NO, 5; inlet flue gas temperature, 65 °C; reaction time, 0.94 s; and H(2)O volume fraction, 8%. Production of O(2)(+) and the plasma reaction mechanisms are discussed, and the recovered acid is characterized. The experimental results show that the present method performs better for denitrification than for desulfurization. Compared with conventional air discharge flue gas treatments, the present method has lower initial investment and operating costs, and the equipment is more compact.

Using stable isotopes to monitor forms of sulfur during desulfurization processes: A quick screening method

USGS Publications Warehouse

Liu, Chao-Li; Hackley, Keith C.; Coleman, D.D.; Kruse, C.W.

1987-01-01

A method using stable isotope ratio analysis to monitor the reactivity of sulfur forms in coal during thermal and chemical desulfurization processes has been developed at the Illinois State Geological Survey. The method is based upon the fact that a significant difference exists in some coals between the 34S/32S ratios of the pyritic and organic sulfur. A screening method for determining the suitability of coal samples for use in isotope ratio analysis is described. Making these special coals available from coal sample programs would assist research groups in sorting out the complex sulfur chemistry which accompanies thermal and chemical processing of high sulfur coals. ?? 1987.

Reduction of spalling in mixed metal oxide desulfurization sorbents by addition of a large promoter metal oxide

DOEpatents

Poston, J.A.

1997-12-02

Mixed metal oxide pellets for removing hydrogen sulfide from fuel gas mixes derived from coal are stabilized for operation over repeated cycles of desulfurization and regeneration reactions by addition of a large promoter metal oxide such as lanthanum trioxide. The pellets, which may be principally made up of a mixed metal oxide such as zinc titanate, exhibit physical stability and lack of spalling or decrepitation over repeated cycles without loss of reactivity. The lanthanum oxide is mixed with pellet-forming components in an amount of 1 to 10 weight percent.

Reduction of spalling in mixed metal oxide desulfurization sorbents by addition of a large promoter metal oxide

DOEpatents

Poston, James A.

1997-01-01

Mixed metal oxide pellets for removing hydrogen sulfide from fuel gas mixes derived from coal are stabilized for operation over repeated cycles of desulfurization and regeneration reactions by addition of a large promoter metal oxide such as lanthanum trioxide. The pellets, which may be principally made up of a mixed metal oxide such as zinc titanate, exhibit physical stability and lack of spalling or decrepitation over repeated cycles without loss of reactivity. The lanthanum oxide is mixed with pellet-forming components in an amount of 1 to 10 weight percent.

Factors influencing gypsum crystal morphology within a flue gas desulfurization vessel

NASA Astrophysics Data System (ADS)

Lewis, Kinsey M.

Flue gas desulfurization (FGD) is utilized by the coal--powered generating industry to safely eliminate sulfur dioxide. A FGD vessel (scrubber) synthetically creates gypsum crystals by combining limestone (CaCO3), SO2 flue gas, water and oxygen resulting in crystalline gypsum (CaSO4 · 2H2O), which can be sold for an economic return. Flat disk--like crystals, opposed to rod--like crystals, are hard to dewater, lowering economic return. The objectives were to investigate the cause of varying morphologies, understand the environment of precipitation, as well as identify correlations between operating conditions and resulting unfavorable gypsum crystal growth. Results show evidence supporting airborne impurities due to the onsite coal pile, the abundance and size of CaCO 3 and high Ca:SO4 ratios within the scrubber as possible factors controlling gypsum crystal morphology. In conclusion, regularly purging the system and incorporating a filter on the air intake valve will provide an economic byproduct avoiding costly landfill deposits.

Method for the desulfurization of hot product gases from coal gasifier

DOEpatents

Grindley, Thomas

1988-01-01

The gasification of sulfur-bearing coal produces a synthesis gas which contains a considerable concentration of sulfur compounds especially hydrogen sulfide that renders the synthesis gas environmentally unacceptable unless the concentration of the sulfur compounds is significantly reduced. To provide for such a reduction in the sulfur compounds a calcium compound is added to the gasifier with the coal to provide some sulfur absorption. The synthesis gas from the gasifier contains sulfur compounds and is passed through an external bed of a regenerable solid absorbent, preferably zinc ferrite, for essentially completed desulfurizing the hot synthesis gas. This absorbent is, in turn, periodically or continuously regenerated by passing a mixture of steam and air or oxygen through the bed for converting absorbed hydrogen sulfide to sulfur dioxide. The resulting tail gas containing sulfur dioxide and steam is injected into the gasifier where the sulfur dioxide is converted by the calcium compound into a stable form of sulfur such as calcium sulfate.

Aptamer-aided target capturing with biocatalytic metal deposition: an electrochemical platform for sensitive detection of cancer cells.

PubMed

Yi, Zi; Li, Xiao-Yan; Gao, Qing; Tang, Li-Juan; Chu, Xia

2013-04-07

A novel aptamer biosensor for cancer cell assay has been reported on the basis of ultrasensitive electrochemical detection. Cancer cell capturing is first accomplished via aptamer-aided recognition, and the cell-aptamer binding events then mediate an alkaline phosphatase-catalyzed silver deposition reaction which can be probed by electrochemical detection. Following biocatalytic silver deposition, an efficient amplification approach for sensitive electrochemical measurements is demonstrated, for cell detection with high sensitivity. Ramos cell are used as a model case, a typical biomarker of the acute blood cell cancer, Burkitt's lymphoma. The results reveal that the developed technique displays desirable selectivity in Ramos cell discrimination, and linear response range from 10 to 10(6) cells with a detection limit as low as 10 cells. Due to the simple procedures, label-free and electrochemistry based detection format, this technique is simple and cost-effective, and exhibits excellent compatibility with miniaturization technologies. The electrochemical cell detection strategy may create an intrinsically specific and sensitive platform for cancer cell assay and associated studies.

Application study of Bio-FGD based on environmental safety during the coal combustion

NASA Astrophysics Data System (ADS)

Zhang, Pin

2018-05-01

Coal combustion produces a large amount of acidic gas, which is the main cause of acid rain and other natural disasters. Flue Gas Desulfurization (FGD) is a necessary requirement for clean coal combustion. Compared with the traditional chemical desulfurization technology, biological desulfurization has the advantages of low operating cost, without secondary pollution, low carbon emission and the additional economic benefits. The process and structure of BioDeSOx which as one of Bio-FGD technology is introduced. The major factors that influent BioDeSOx Bio- FGD system is the pH, oxidation reduction potential (-300 MV to -400MV), electrical conductivity, the adding amount of nutrient and temperature (30°C-40°C). Taking the Bio- FGD project of Yixing xielian thermal power plant as an example, the BioDeSOx technology was applied in this project. The environmental and economic benefits of the project were greater than the traditional desulfurization technology. With the continuous improvement of environmental safety standards, Bio- FGD technology will have broad application prospects.

Catalytic oxidative desulfurization of liquid hydrocarbon fuels using air

NASA Astrophysics Data System (ADS)

Sundararaman, Ramanathan

Conventional approaches to oxidative desulfurization of liquid hydrocarbons involve use of high-purity, expensive water soluble peroxide for oxidation of sulfur compounds followed by post-treatment for removal of oxidized sulfones by extraction. Both are associated with higher cost due to handling, storage of oxidants and yield loss with extraction and water separation, making the whole process more expensive. This thesis explores an oxidative desulfurization process using air as an oxidant followed by catalytic decomposition of sulfones thereby eliminating the aforementioned issues. Oxidation of sulfur compounds was realized by a two step process in which peroxides were first generated in-situ by catalytic air oxidation, followed by catalytic oxidation of S compounds using the peroxides generated in-situ completing the two step approach. By this technique it was feasible to oxidize over 90% of sulfur compounds present in real jet (520 ppmw S) and diesel (41 ppmw S) fuels. Screening of bulk and supported CuO based catalysts for peroxide generation using model aromatic compound representing diesel fuel showed that bulk CuO catalyst was more effective in producing peroxides with high yield and selectivity. Testing of three real diesel fuels obtained from different sources for air oxidation over bulk CuO catalyst showed different level of effectiveness for generating peroxides in-situ which was consistent with air oxidation of representative model aromatic compounds. Peroxides generated in-situ was then used as an oxidant to oxidize sulfur compounds present in the fuel over MoO3/SiO2 catalyst. 81% selectivity of peroxides for oxidation of sulfur compounds was observed on MoO3/SiO2 catalyst at 40 °C and under similar conditions MoO3/Al2O3 gave only 41% selectivity. This difference in selectivity might be related to the difference in the nature of active sites of MoO3 on SiO2 and Al2O 3 supports as suggested by H2-TPR and XRD analyses. Testing of supported and bulk Mg

Deep oxidative desulfurization of dibenzothiophene in simulated oil and real diesel using heteropolyanion-substituted hydrotalcite-like compounds as catalysts.

PubMed

Yu, Fengli; Wang, Rui

2013-11-05

Three heteropolyanion substituted hydrotalcite-like compounds (HPA-HTLcs) including Mg₉Al₃(OH)₂₄[PW₁₂O₄₀](MgAl-PW₁₂), Mg₉Al₃(OH)₂₄[PMo₁₂O₄₀] (MgAl-PMo₁₂) and Mg₁₂Al₄(OH)₃₂[SiW₁₂O₄₀] (MgAl-SiW₁₂), were synthesized, characterized and used as catalysts for the oxidative desulfurization of simulated oil (dibenzothiophene, DBT, in n-octane). MgAl-PMo₁₂ was identified as an effective catalyst for the oxidative removal of DBT under very mild conditions of atmospheric pressure and 60 °C in a biphasic system using hydrogen peroxide as oxidant and acetonitrile as extractant. The conversion of DBT was nearly 100%. As a result, because of the influence of the electron density and the space steric hindrance, the oxidation reactivity of the different sulfur compounds in simulated oil followed the order DBT > 4,6-dimethyldibenzothiophene (4,6-DMDBT) > benzothiophene (BT) > thiophene (TH). When the reaction is finished, the catalysts can be recovered from the acetonitrile phase by filtration. The recovered MgAl-PMo₁₂ retains nearly the same catalytic activity as the fresh material. Moreover, MgAl-PMo₁₂ was found to exhibit an ideal catalytic activity in the oxidative desulfurization of real diesel resulting in a total remaining sulfur content of 9.12 ppm(w).

Surface modification of calcium sulfate whisker prepared from flue gas desulfurization gypsum

NASA Astrophysics Data System (ADS)

Liu, Chengjun; Zhao, Qing; Wang, Yeguang; Shi, Peiyang; Jiang, Maofa

2016-01-01

In order to obtain hydrophobic whisker for preparing polymeric composite product, the calcium sulfate whisker (CSW) prepared from flue gas desulfurization (FGD) gypsum by hydrothermal synthesis was modified by various surfactants, and the effects of some modification conditions on the hydrophobic property of CSW were investigated in this study. Sodium stearate was considered to be a suitable surfactant and its reasonable dosage was 2% of ethanol solvent. Both physical and chemical absorptions were found in the surface modification process, and the later one was suggested to preferentially occur on the CSW surface. Moreover, modifying temperature, modifying duration, and agitation speed were experimentally found to have a remarkable influence on the modification behavior. Active ratio reached 0.845 when the modification process was conducted under reasonable conditions obtained in the current work. Finally, polypropylene sheet products were prepared from modified CSW showing an excellence mechanical property.

Actinobase: Database on molecular diversity, phylogeny and biocatalytic potential of salt tolerant alkaliphilic actinomycetes.

PubMed

Sharma, Amit K; Gohel, Sangeeta; Singh, Satya P

2012-01-01

Actinobase is a relational database of molecular diversity, phylogeny and biocatalytic potential of haloalkaliphilic actinomycetes. The main objective of this data base is to provide easy access to range of information, data storage, comparison and analysis apart from reduced data redundancy, data entry, storage, retrieval costs and improve data security. Information related to habitat, cell morphology, Gram reaction, biochemical characterization and molecular features would allow researchers in understanding identification and stress adaptation of the existing and new candidates belonging to salt tolerant alkaliphilic actinomycetes. The PHP front end helps to add nucleotides and protein sequence of reported entries which directly help researchers to obtain the required details. Analysis of the genus wise status of the salt tolerant alkaliphilic actinomycetes indicated 6 different genera among the 40 classified entries of the salt tolerant alkaliphilic actinomycetes. The results represented wide spread occurrence of salt tolerant alkaliphilic actinomycetes belonging to diverse taxonomic positions. Entries and information related to actinomycetes in the database are publicly accessible at http://www.actinobase.in. On clustalW/X multiple sequence alignment of the alkaline protease gene sequences, different clusters emerged among the groups. The narrow search and limit options of the constructed database provided comparable information. The user friendly access to PHP front end facilitates would facilitate addition of sequences of reported entries. The database is available for free at http://www.actinobase.in.

Preparation of WO3/g-C3N4 composites and their application in oxidative desulfurization

NASA Astrophysics Data System (ADS)

Zhao, Rongxiang; Li, Xiuping; Su, Jianxun; Gao, Xiaohan

2017-01-01

WO3/graphitic carbon nitride (g-C3N4) composites were successfully synthesized through direct calcining of a mixture of WO3 and g-C3N4 at 400 °C for 2 h. The WO3 was prepared by calcination of phosphotungstic acid at 550 °C for 4 h, and the g-C3N4 was obtained by calcination of melamine at 520 °C for 4 h. The WO3/g-C3N4 composites were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and Brunner-Emmett-Teller analysis (BET). The WO3/g-C3N4 composites exhibited stronger XRD peaks of WO3 and g-C3N4 than the WO3 and pure g-C3N4. In addition, two WO3 peaks at 25.7° and 26.6° emerged for the 36% -WO3/g-C3N4 composite. This finding indicated that WO3 was highly dispersed on the surface of the g-C3N4 nanosheets and interacted with the nanosheets, which resulted in the appearance of (012) and (022) planes of WO3. The WO3/g-C3N4 composite also exhibited a larger specific surface area and higher degree of crystallization than WO3 or pure g-C3N4, which resulted in high catalytic activity of the catalyst. Desulfurization experiments demonstrated that the desulfurization rate of dibenzothiophene (DBT) in model oil reached 91.2% under optimal conditions. Moreover, the activity of the catalyst was not significantly decreased after five recycles.

Solvent Stability Study with Thermodynamic Analysis and Superior Biocatalytic Activity of Burkholderia cepacia Lipase Immobilized on Biocompatible Hybrid Matrix of Poly(vinyl alcohol) and Hypromellose.

PubMed

Badgujar, Kirtikumar C; Bhanage, Bhalchandra M

2014-12-26

In the present study, we have synthesized a biocompatible hybrid carrier of hypromellose (HY) and poly(vinyl alcohol) (PVA) for immobilization of Burkholderia cepacia lipase (BCL). The immobilized biocatalyst HY:PVA:BCL was subjected to determination of half-life time (τ) and deactivation rate constant (K(D)) in various organic solvents. Biocatalyst showed higher τ-value in a nonpolar solvent like cyclohexane (822 h) as compared to that of a polar solvent such as acetone (347 h), which signifies better compatibility of biocatalyst in the nonpolar solvents. Furthermore, the K(D)-value was found to be less in cyclohexane (0.843 × 10(-3)) as compared to acetone (1.997 × 10(-3)), indicating better stability in the nonpolar solvents. Immobilized-BCL (35 mg) was sufficient to achieve 99% conversion of phenethyl butyrate (natural constituent of essential oils and has wide industrial applications) using phenethyl alcohol (2 mmol) and vinyl butyrate (6 mmol) at 44 °C in 3 h. The activation energy (E(a)) was found to be lower for immobilized-BCL than crude-BCL, indicating better catalytic efficiency of immobilized lipase BCL. The immobilized-BCL reported 6-fold superior biocatalytic activity and 8 times recyclability as compared to crude-BCL. Improved catalytic activity of immobilized enzyme in nonpolar media was also supported by thermodynamic activation parameters such as enthalpy (ΔH(⧧)), entropy (ΔS(⧧)) and Gibb's free energy (ΔG(⧧)) study, which showed that phenethyl butyrate synthesis catalyzed by immobilized-BCL was feasible as compared to crude-BCL. The present work explains a thermodynamic investigation and superior biocatalytic activity for phenethyl butyrate synthesis using biocompatible immobilized HY:PVA:BCL in nonaqueous media for the first time.

Recovery of SO2 and MgO from By-Products of MgO Wet Flue Gas Desulfurization

PubMed Central

Yan, Liyun; Lu, Xiaofeng; Wang, Quanhai; Guo, Qiang

2014-01-01

Abstract An industrial demonstration unit using natural gas as a heat source was built to calcine the by-products of MgO wet flue gas desulfurization from power plants; influencing factors on the SO2 content in calciner gas were comprehensively analyzed; and an advantageous recycling condition of MgO and SO2 from by-products was summarized. Results showed that the SO2 content in the calciner gas was increased by more than 10 times under a lower excess air coefficient, a higher feed rate, a lower crystal water in by-products, and a higher feed port position. For the tests conducted under the excess air coefficient above and below one, the effect of the furnace temperature on the SO2 content in the calciner gas was reversed. Results of activity analysis indicate that particles of MgO generated under the calcination temperature of 900–1,000°C had a high activity. In contrast, due to the slight sintering, MgO generated under the calcination temperature of 1,100°C had a low activity. To recycle SO2 as well as MgO, a temperature range of 900–927°C for TE103 is proposed. These studies will prompt the desulfurization market diversification, reduce the sulfur's dependence on imports for making sulfuric acid, be meaningful to balance the usage of the natural resource in China, and be regarded as a reference for the development of this technology for other similar developing countries. PMID:25371652

Capturing CO2 from Coal-Fired Power Plants: Challenges for a Comprehensive Strategy

DTIC Science & Technology

2008-08-15

efficient flue gas desulfurization (FGD) or selective catalytic reduction (SCR) devices (or none), requiring either upgrading of existing FGD and SCR...saturated flue Figure 6. CO2 Price Projections CRS-16 42 Donald Shattuck, et al., A History of Flue Gas Desulfurization (FGD) — The Early Years, UE Technical...available in both the eastern and western parts of the United States, or by the use of emerging flue gas desulfurization (FGD) devices.46 At the time

Phosphotungstic acid encapsulated in the mesocages of amine-functionalized metal-organic frameworks for catalytic oxidative desulfurization.

PubMed

Wang, Xu-Sheng; Huang, Yuan-Biao; Lin, Zu-Jin; Cao, Rong

2014-08-21

Highly dispersed Keggin-type phosphotungstic acid (H3PW12O40, PTA) encapsulated in the mesocages of amine-functionalized metal-organic frameworks MIL-101(Cr)-NH2 has been prepared by an anion-exchange method. PTA anions (PW12O40(3-)) are stabilized in the mesocages via the electrostatic interaction with amino groups of the MIL-101(Cr)-NH2. The obtained catalyst (denoted PTA@MIL-101(Cr)-NH2) exhibits high catalytic activity in the extractive and catalytic oxidative desulfurization (ECODS) system under mild conditions. Moreover, it can be easily recovered and recycled several times without leaching and loss of activity.

Advanced Flue Gas Desulfurization (AFGD) Demonstration Project, A DOE Assessment

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

National Energy Technology Laboratory

2001-08-31

The AFGD process as demonstrated by Pure Air at the Bailly Station offers a reliable and cost-effective means of achieving a high degree of SO{sub 2} emissions reduction when burning high-sulfur coals. Many innovative features have been successfully incorporated in this process, and it is ready for widespread commercial use. The system uses a single-loop cocurrent scrubbing process with in-situ oxidation to produce wallboard-grade gypsum instead of wet sludge. A novel wastewater evaporation system minimizes effluents. The advanced scrubbing process uses a common absorber to serve multiple boilers, thereby saving on capital through economies of scale. Major results of themore » project are: (1) SO{sub 2} removal of over 94 percent was achieved over the three-year demonstration period, with a system availability exceeding 99.5 percent; (2) a large, single absorber handled the combined flue gas of boilers generating 528 MWe of power, and no spares were required; (3) direct injection of pulverized limestone into the absorber was successful; (4) Wastewater evaporation eliminated the need for liquid waste disposal; and (5) the gypsum by-product was used directly for wallboard manufacture, eliminating the need to dispose of waste sludge.« less

Surface characterization of adsorbents in ultrasound-assisted oxidative desulfurization process of fossil fuels.

PubMed

Etemadi, Omid; Yen, Teh Fu

2007-09-01

Surface properties of two different phases of alumina were studied through SEM images. Characterization of amorphous acidic alumina and crystalline boehmite by XRD explains the differences in adsorption capacities of each sample. Data from small angle neutron scattering (SANS) provide further results regarding the ordering in amorphous and crystalline samples of alumina. Quantitative measurements from SANS are used for pore size calculations. Higher disorder provides more topological traps, irregularities, and hidden grooves for higher adsorption capacity. An isotherm model was derived for adsorption of dibenzothiophene sulfone (DBTO) by amorphous acidic alumina to predict and calculate the adsorption of sulfur compounds. The Langmuir-Freundlich model covers a wide range of sulfur concentrations. Experiments prove that amorphous acidic alumina is the adsorbent of choice for selective adsorption in the ultrasound-assisted oxidative desulfurization (UAOD) process to produce ultra-low-sulfur fuel (ULSF).

Controllability analysis and decentralized control of a wet limestone flue gas desulfurization plant

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

Perales, A.L.V.; Ortiz, F.J.G.; Ollero, P.

2008-12-15

Presently, decentralized feedback control is the only control strategy used in wet limestone flue gas desulfurization (WLFGD) plants. Proper tuning of this control strategy is becoming an important issue in WLFGD plants because more stringent SO{sub 2} regulations have come into force recently. Controllability analysis is a highly valuable tool for proper design of control systems, but it has not been applied to WLFGD plants so far. In this paper a decentralized control strategy is designed and applied to a WLFGD pilot plant taking into account the conclusions of a controllability analysis. The results reveal that good SO{sub 2} controlmore » in WLFGD plants can be achieved mainly because the main disturbance of the process is well-aligned with the plant and interactions between control loops are beneficial to SO{sub 2} control.« less

PrenDB, a Substrate Prediction Database to Enable Biocatalytic Use of Prenyltransferases.

PubMed

Gunera, Jakub; Kindinger, Florian; Li, Shu-Ming; Kolb, Peter

2017-03-10

Prenyltransferases of the dimethylallyltryptophan synthase (DMATS) superfamily catalyze the attachment of prenyl or prenyl-like moieties to diverse acceptor compounds. These acceptor molecules are generally aromatic in nature and mostly indole or indole-like. Their catalytic transformation represents a major skeletal diversification step in the biosynthesis of secondary metabolites, including the indole alkaloids. DMATS enzymes thus contribute significantly to the biological and pharmacological diversity of small molecule metabolites. Understanding the substrate specificity of these enzymes could create opportunities for their biocatalytic use in preparing complex synthetic scaffolds. However, there has been no framework to achieve this in a rational way. Here, we report a chemoinformatic pipeline to enable prenyltransferase substrate prediction. We systematically catalogued 32 unique prenyltransferases and 167 unique substrates to create possible reaction matrices and compiled these data into a browsable database named PrenDB. We then used a newly developed algorithm based on molecular fragmentation to automatically extract reactive chemical epitopes. The analysis of the collected data sheds light on the thus far explored substrate space of DMATS enzymes. To assess the predictive performance of our virtual reaction extraction tool, 38 potential substrates were tested as prenyl acceptors in assays with three prenyltransferases, and we were able to detect turnover in >55% of the cases. The database, PrenDB (www.kolblab.org/prendb.php), enables the prediction of potential substrates for chemoenzymatic synthesis through substructure similarity and virtual chemical transformation techniques. It aims at making prenyltransferases and their highly regio- and stereoselective reactions accessible to the research community for integration in synthetic work flows. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Adsorptive desulfurization with metal-organic frameworks: A density functional theory investigation

NASA Astrophysics Data System (ADS)

Chen, Zhiping; Ling, Lixia; Wang, Baojun; Fan, Huiling; Shangguan, Ju; Mi, Jie

2016-11-01

The contribution of each fragment of metal-organic frameworks (MOFs) to the adsorption of sulfur compounds were investigated using density functional theory (DFT). The involved sulfur compounds are dimethyl sulfide (CH3SCH3), ethyl mercaptan (CH3CH2SH) and hydrogen sulfide (H2S). MOFs with different organic ligands (NH2-BDC, BDC and NDC), metal centers structures (M, M-M and M3O) and metal ions (Zn, Cu and Fe) were used to study their effects on sulfur species adsorption. The results revealed that, MOFs with coordinatively unsaturated sites (CUS) have the strongest binding strength with sulfur compounds, MOFs with NH2-BDC substituent group ligand comes second, followed by that with saturated metal center, and the organic ligands without substituent group has the weakest adsorption strength. Moreover, it was also found that, among different metal ions (Fe, Zn and Cu), MOFs with unsaturated Fe has the strongest adsorption strength for sulfur compounds. These results are consistent with our previous experimental observations, and therefore provide insights on the better design of MOFs for desulfurization application.

Evidences for CYP3A4 autoactivation in the desulfuration of dimethoate by the human liver.

PubMed

Buratti, Franca M; Testai, Emanuela

2007-11-20

Dimethoate (DIM) is an organophosphorothionate (OPT) pesticide used worldwide as a systemic insecticide and acaricide. It is characterized by low-to-moderate acute mammalian toxicity; similarly to the other OPT pesticides, its mode of action is mediated by the inhibition of acetylcholinesterase (AChE), exerted by its toxic metabolite dimethoate-oxon or omethoate (OME), which is also used as a direct acting pesticide. Human hepatic DIM bioactivation to the toxic metabolite OME has been characterized by using c-DNA expressed human CYPs and human liver microsomes (HLM) also in the presence of CYP-specific chemical inhibitors, with a method based on AChE inhibition. The obtained kinetic parameters and AChE IC(50) have been compared with those previously obtained with other OPTs, indicating a lower efficiency in DIM desulfuration reaction and a lower potency in inhibiting AChE. Results showed that, similarly to the other OPTs tested so far, at low DIM concentration OME formation is mainly catalysed by CYP1A2, while the role of 3A4 is relevant at high DIM levels. Differently from the other OPTs, DIM desulfuration reaction showed an atypical kinetic profile, likely due to CYP3A4 autoactivation. The sigmoidicity degree of the activity curve increased with the level of CYP3A4 in HLM or disappeared in the presence of a CYP3A4 chemical inhibitor. This atypical kinetic behaviour can be considered one of the possible explanations for the recent findings that among patients hospitalized following OPT intoxication, DIM ingestion gave different symptoms and more severe poisoning (23.1% of fatal cases versus total) than chlorpyrifos (8% of deaths), which has a lower LD(50) value. Since DIM-poisoned patients poorly responded to pralidoxime, the possibility to use CYP3A4 inhibitors could be considered as a complementary treatment.

Desulfurization from thiophene by SO(4)(2-)/ZrO(2) catalytic oxidation at room temperature and atmospheric pressure.

PubMed

Wang, Bo; Zhu, Jianpeng; Ma, Hongzhu

2009-05-15

Thiophene, due to its poison, together with its combustion products which causes air pollution and highly toxic characteristic itself, attracted more and more attention to remove from gasoline and some high concentration systems. As the purpose of achieving the novel method of de-thiophene assisted by SO(4)(2-)/ZrO(2) (SZ), three reactions about thiophene in different atmosphere at room temperature and atmospheric pressure were investigated. SO(4)(2-)/ZrO(2) catalyst were synthesized and characterized by X-ray photoelectron spectroscopy (XPS), Fourier transformation infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The products were detected by gas chromatography-mass spectrometry (GC-MS). XP spectra show that ozone-catalyst system (SZO) have two forms of sulfur element (S(6+) and S(2-)) on the catalyst surface, which distinguished from that of air-catalyst system (SZA) and blank-catalyst system (SZB) (S(6+)). And the results of GC-MS exhibited that some new compounds has been produced under this extremely mild condition. Especially, many kinds of sulfur compounds containing oxygen, that is easier to be extracted by oxidative desulfurization (ODS), have been detected in the SZA-1.5h and SZB-3h system. In addition, some long chain hydrocarbons have also been detected. While in SZO-0.5h system, only long chain hydrocarbons were found. The results show that total efficiency of desulfurization from thiophene with ozone near to 100% can be obtained with the SO(4)(2-)/ZrO(2) catalytic oxidation reaction.

Coal desulfurization by a microwave process. Technical progress report, February 1981-May 1981

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

Zavitsanos, P.D.; Golden, J.A.; Bleiler, K.W.

1981-01-01

Desulfurization experiments were carried out using the 6KW, 2450 MHz Flow Reactor System. The program has been directed toward the combination of physical separation and microwave exposure with NaOH to increase sulfur removal. The following treatment sequence has been used with good results: (1) expose 1/4 to 1 in. raw coal to microwaves; (2) crush the treated coal and separate the sample into float/sink fractions; (3) add NaOH to the float fraction and re-expose the sample to microwaves; and (4) wash, add NaOH and expose to microwaves. This procedure has produced up to 89% sulfur removal and as low asmore » 0.31 numberS/10/sup 6/ Btu. Ash analyses on these samples showed as high as 40% reduction. The calorific value was increased in almost all samples. Data on sulfur, ash and calorific values are summarized.« less

Survey of flue gas desulfurization systems: Dickerson Station, Potomac Electric Power Co. Final report, Feb--Aug 1975

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

Isaacs, G.A.

1975-09-01

Results are given of a survey of a flue gas desulfurization system, utilizing the Chemico/Basic MgO-SO2 removal/recovery process, that has been retrofitted to handle approximately half of the exhaust gas from the 190 MW unit 3 at Potomac Electric Power Company's Dickerson Station. The system was installed at a cost of SO.5 million. The boiler burns 2% sulfur coal and is equipped with a 94% efficient electrostatic precipitator. A single two-stage scrubber/absorber is used. The liquor streams for the two stages are separate, both operating in a closed-loop mode. Magnesium oxide (MgO) is regenerated off-site. (GRA)

Biocatalytic degradation of pharmaceuticals, personal care products, industrial chemicals, steroid hormones and pesticides in a membrane distillation-enzymatic bioreactor.

PubMed

Asif, Muhammad B; Hai, Faisal I; Kang, Jinguo; van de Merwe, Jason P; Leusch, Frederic D L; Price, William E; Nghiem, Long D

2018-01-01

Laccase-catalyzed degradation of a broad spectrum of trace organic contaminants (TrOCs) by a membrane distillation (MD)-enzymatic membrane bioreactor (EMBR) was investigated. The MD component effectively retained TrOCs (94-99%) in the EMBR, facilitating their continuous biocatalytic degradation. Notably, the extent of TrOC degradation was strongly influenced by their molecular properties. A significant degradation (above 90%) of TrOCs containing strong electron donating functional groups (e.g., hydroxyl and amine groups) was achieved, while a moderate removal was observed for TrOCs containing electron withdrawing functional groups (e.g., amide and halogen groups). Separate addition of two redox-mediators, namely syringaldehyde and violuric acid, further improved TrOC degradation by laccase. However, a mixture of both showed a reduced performance for a few pharmaceuticals such as primidone, carbamazepine and ibuprofen. Mediator addition increased the toxicity of the media in the enzymatic bioreactor, but the membrane permeate (i.e., final effluent) was non-toxic, suggesting an added advantage of coupling MD with EMBR. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis of 2-azaindolizines by using an iodine-mediated oxidative desulfurization promoted cyclization of N-2-pyridylmethyl thioamides and an investigation of their photophysical properties.

PubMed

Shibahara, Fumitoshi; Kitagawa, Asumi; Yamaguchi, Eiji; Murai, Toshiaki

2006-11-23

Iodine-mediated, oxidative desulfurization promoted cyclization of N-2-pyridylmethyl thioamides serves as an efficient and versatile method for the preparation of 2-azaindolizines (imidazo[1,5-a]pyridines) and rare 2-azaindolizine sulfur-bridged dimers. The 2-azaindolizines prepared in this manner are readily converted to a variety of fluorescent compounds by using transition-metal-catalyzed cross-coupling reactions. [reaction: see text].

Ultra-deep desulfurization via reactive adsorption on peroxophosphomolybdate/agarose hybrids.

PubMed

Xu, Jian; Li, Huacheng; Wang, Shengtian; Luo, Fang; Liu, Yunyu; Wang, Xiaohong; Jiang, Zijiang

2014-09-01

A catalyst system composed of peroxophosphomolybdates as catalytic center and agarose as matrix material had been designed. The [C16H33N(CH3)3]3[PO4{MoO(O2)2}4]/agarose (C16PMo(O2)2/agarose) hybrid was found to be active for oxidation desulfurization (ODS) of dibenzothiophene (DBT) or real fuel into corresponding sulfone by H2O2 as an oxidant, while the sulfur content could be reduced to 5ppm. The higher activity comes from its components including [PO4{MoO(O2)2}4] catalytic sites, the hydrophobic quaternary ammonium cation affinity to low polarity substrates, and agarose matrix affinity to H2O2 and sulfone. During the oxidative reaction, the mass transfer resistance between H2O2 and organic sulfurs could be decreased and the reaction rate could increase by the assistance of agarose and hydrophobic tails of [C16H33N(CH3)3]3[PO4{MoO(O2)2}4]. Meanwhile, the oxidative products could be adsorbed by agarose matrix to give clean fuel avoiding the post-treatment. In addition, the hybrid was easily regenerated to be reused. Copyright © 2014 Elsevier Ltd. All rights reserved.

Apparatus and method for the desulfurization of petroleum by bacteria

DOEpatents

Lizama, Hector M.; Scott, Timothy C.; Scott, Charles D.

1995-01-01

A method for treating petroleum with anaerobic microorganisms acting as biocatalysts that can remove sulfur atoms from hydrocarbon molecules, under anaerobic conditions, and then convert the sulfur atoms to hydrogen sulfide. The microorganisms utilized are from the family known as the "Sulfate Reducing Bacteria." These bacteria generate metabolic energy from the oxidation of organic compounds, but use oxidized forms of sulfur as an electron acceptor. Because the biocatalyst is present in the form of bacteria in an aqueous suspension, whereas the reacting substrate consists of hydrocarbon molecules in an organic phase, the actual desulfurization reaction takes place at the aqueous-organic interphase. To ensure adequate interfacial contacting and mass transfer, a biphasic electrostatic bioreactor system is utilized. The bioreactor is utilized to disperse and recoalesce a biocatalyst contained in the aqueous liquid phase into the organic liquid phase containing the sulfur. High-intensity electrical fields rupture the aqueous drops into a plurality of microdroplets and induce continuous coalescence and redispersion as the microdroplets travel through the organic phase, thus increasing surface area. As the aqueous microdroplets progress through the organic phase, the biocatalyst then reacts with the sulfur to produce hydrogen sulfide which is then removed from the bioreactor. The organic liquid, now free of the sulfur, is ready for immediate use or further processing.

A polyoxometalate-encapsulating cationic metal-organic framework as a heterogeneous catalyst for desulfurization.

PubMed

Hao, Xiu-Li; Ma, Yuan-Yuan; Zang, Hong-Ying; Wang, Yong-Hui; Li, Yang-Guang; Wang, En-Bo

2015-02-23

A new cationic triazole-based metal-organic framework encapsulating Keggin-type polyoxometalates, with the molecular formula [Co(BBPTZ)3][HPMo12O40]⋅24 H2O [compound 1; BBPTZ = 4,4'-bis(1,2,4-triazol-1-ylmethyl)biphenyl] is hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. The structure of compound 1 contains a non-interpenetrated 3D CdSO4 (cds)-type framework with two types of channels that are interconnected with each other; straight channels that are occupied by the Keggin-type POM anions, and wavelike channels that contain lattice water molecules. The catalytic activity of compound 1 in the oxidative desulfurization reaction indicates that it is not only an effective and size-selective heterogeneous catalyst, but it also exhibits distinct structural stability in the catalytic reaction system. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Effect of Oxygen Supply on the Dual Growth Kinetics of Acidithiobacillus thiooxidans under Acidic Conditions for Biogas Desulfurization

PubMed Central

Namgung, Hyeong-Kyu; Song, JiHyeon

2015-01-01

In this study, to simulate a biogas desulfurization process, a modified Monod-Gompertz kinetic model incorporating a dissolved oxygen (DO) effect was proposed for a sulfur-oxidizing bacterial (SOB) strain, Acidithiobacillus thiooxidans, under extremely acidic conditions of pH 2. The kinetic model was calibrated and validated using experimental data obtained from a bubble-column bioreactor. The SOB strain was effective for H2S degradation, but the H2S removal efficiency dropped rapidly at DO concentrations less than 2.0 mg/L. A low H2S loading was effectively treated with oxygen supplied in a range of 2%–6%, but a H2S guideline of 10 ppm could not be met, even with an oxygen supply greater than 6%, when the H2S loading was high at a short gas retention time of 1 min and a H2S inlet concentration of 5000 ppm. The oxygen supply should be increased in the aerobic desulfurization to meet the H2S guideline; however, the excess oxygen above the optimum was not effective because of the decline in oxygen efficiency. The model estimation indicated that the maximum H2S removal rate was approximately 400 ppm/%-O2 at the influent oxygen concentration of 4.9% under the given condition. The kinetic model with a low DO threshold for the interacting substrates was a useful tool to simulate the effect of the oxygen supply on the H2S removal and to determine the optimal oxygen concentration. PMID:25633028

Phosphotriesterase-magnetic nanoparticles bioconjugates with improved enzyme activity in a biocatalytic membrane reactor.

PubMed

Gebreyohannes, Abaynesh Yihdego; Mazzei, Rosalinda; Yahia Marei Abdelrahim, Mohamed; Vitola, Giuseppe; Porzio, Elena; Manco, Giuseppe; Barboiu, Mihail; Giorno, Lidietta

2018-05-24

The need to find alternative bioremediation solutions for organophosphate degradation pushed the research to develop technologies based on organophosphate degrading enzymes, such as phosphotriesterase. The use of free phosphotriesterase poses limits in terms of enzyme reuse, stability and process development. The heterogenization of enzyme on a support and their use in bioreactors implemented by membrane seems a suitable strategy, thanks to the ability of membranes to compartmentalize, to govern mass transfer and provide microenvironment with tuned physico-chemical and structural properties. Usually, hydrophilic membranes are used since they easily guarantee the presence of water molecules needed for the enzyme catalytic activity. However, hydrophobic materials exhibit a larger shelf life and are preferred for the construction of filters and masks. Therefore, in this work, hydrophobic polyvinylidene fluoride (PVDF) porous membranes were used to develop biocatalytic membrane reactors (BMR). The phosphotriesterase-like lactonase (PLL) enzyme (SsoPox triple mutant from S. solfataricus) endowed with thermostable phosphotriesterase activity was used as model biocatalyst. The enzyme was covalently bound directly to the PVDF hydrophobic membrane or it was bound to magnetic nanoparticles and then positioned on the hydrophobic membrane surface by means of an external magnetic field. Investigation of kinetic properties of the two BMRs and the influence of immobilized enzyme amount revealed that the performance of the BMR was mostly dependent on the amount of enzyme and its distribution on the immobilization support. Magnetic nanocomposite mediated immobilization showed a much better performance, with an observed specific activity higher than 90% compared to grafting of the enzyme on the membrane. Even though the present work focused on phosphotriesterase, it can be easily translated to other class of enzymes and related application.

Desulfurization of coal by microbial column flotation.

PubMed

Ohmura, N; Saiki, H

1994-06-05

Twenty-three strains capable of oxidizing iron were isolated from coal and ore storage sites as well as coal and ore mines, volcanic areas, and hot spring. Four strains were found to have high iron-oxidizing activity. One strain (T-4) was selected for this experiment since the strain showed the fastest leaching rate of iron and sulfate from pyrite among the four strains. The T-4 strain was assigned for Thiobacillus ferrooxidans from its cultural and morphological characteristics.Bacterial treatment was applied to column flotation. An increase of cell density in the microbial column flotation resulted in the increase of pyrite removal from a coal-pyrite mixture (high sulfur imitated coal) with corresponding decrease of coal recovery. The addition of kerosene into the microbial column flotation increased the recovery of the imitated coal from 55% (without kerosene) to 81% (with 50 microL/L kerosene) with the reduction of pyrite sulfur content from 11% (feed coal) to 3.9% (product coal). The kerosene addition could reduce the pyritic sulfur content by collecting the coal in the recovery. However, the addition could not enhance separation of pyrite from the coal-pyrite mixture, since pyrite rejection was not affected by the increase of the kerosene addition. An excellent separation was obtained by the microbial flotation using a long column which had a length-diameter (L/D) ratio of 12.7. The long column flotation reduced the pyritic sulfur content from 11% (feed coal) to 1.8% (product coal) when 80% of the feed coal was recovered without the kerosene addition. The long column flotation not only attained an excellent separation but also reduced the amount of cells for desulfurization to as little as one-tenth of the reported amount.

Bicarbonate-induced activation of H₂O₂ for metal-free oxidative desulfurization.

PubMed

Bokare, Alok D; Choi, Wonyong

2016-03-05

Efficient oxidative desulfurization (ODS) of model oil containing dibenzothiophene (DBT) and aromatic thiophenic derivatives has been achieved at room temperature using hydrogen peroxide activation by inorganic bicarbonate (HCO3(-)). Using in-situ formation of peroxymonocarbonate as oxidant, the transformation of main model substrate DBT to corresponding DBT-sulfone was easily accomplished in biphasic reaction conditions. In the presence of water-acetonitrile polar phase, increasing the water content upto 50% decreased the extraction capacity more than 3 times, but ∼ 90% DBT oxidation was still achieved. The oxidizing capacity of bicarbonate catalyst was maintained during repeated ODS cycles, but DBT removal efficiency was critically dependent on the extraction capacity of the polar phase. Under heterogeneous reaction conditions, bicarbonate-modified ion-exchange resin achieved similar ODS activity compared to the homogeneous catalytic system. Additionally, the efficient formation of peroxymonocarbonate using gaseous CO2 precursor in alkaline conditions was also utilized for DBT oxidation. The present study proposes the NaHCO3/H2O2 catalytic system as an efficient and cheap metal-free alternative for the oxidative removal of aromatic sulfur compounds from fuel oil. Copyright © 2015 Elsevier B.V. All rights reserved.

Biogas desulfurization and biogas upgrading using a hybrid membrane system--modeling study.

PubMed

Makaruk, A; Miltner, M; Harasek, M

2013-01-01

Membrane gas permeation using glassy membranes proved to be a suitable method for biogas upgrading and natural gas substitute production on account of low energy consumption and high compactness. Glassy membranes are very effective in the separation of bulk carbon dioxide and water from a methane-containing stream. However, the content of hydrogen sulfide can be lowered only partially. This work employs process modeling based upon the finite difference method to evaluate a hybrid membrane system built of a combination of rubbery and glassy membranes. The former are responsible for the separation of hydrogen sulfide and the latter separate carbon dioxide to produce standard-conform natural gas substitute. The evaluation focuses on the most critical upgrading parameters like achievable gas purity, methane recovery and specific energy consumption. The obtained results indicate that the evaluated hybrid membrane configuration is a potentially efficient system for the biogas processing tasks that do not require high methane recoveries, and allows effective desulfurization for medium and high hydrogen sulfide concentrations without additional process steps.

Mechanism of extractive/oxidative desulfurization using the ionic liquid inimidazole acetate: a computational study.

PubMed

Wang, Hanlu; Xu, Mingsheng; Zhou, Rujin

2017-02-01

The dual role of the ionic liquid 1-butyl-3-methyl-imidazolium trifluoroacetic acid ([C 4 mim]TFA) as an extractant for thiophene (TH) and a catalyst for the oxidation of TH was explored at the molecular level by performing density functional theory (DFT) calculations. The calculated interaction energies demonstrated why [C 4 mim]TFA is a better extractant for thiophene sulfone (THO 2 ) than for TH. Two pathways were proposed for the oxidation of TH to THO 2 with [C 4 mim]TFA acting as a catalyst. In the dominant pathway, a peracid is formed which then oxidizes TH to the sulfoxide and sulfones. The presence of [C 4 mim]TFA was found to greatly reduce the barrier to the oxidative desulfurization (ODS) of TH using H 2 O 2 as an oxidant. Graphical Abstract Possible reaction mechanisms of TH with the aid of [C4mim]TFAᅟ.

Combination of deep eutectic solvent and ionic liquid to improve biocatalytic reduction of 2-octanone with Acetobacter pasteurianus GIM1.158 cell

NASA Astrophysics Data System (ADS)

Xu, Pei; Du, Peng-Xuan; Zong, Min-Hua; Li, Ning; Lou, Wen-Yong

2016-05-01

The efficient anti-Prelog asymmetric reduction of 2-octanone with Acetobacter pasteurianus GIM1.158 cells was successfully performed in a biphasic system consisting of deep eutectic solvent (DES) and water-immiscible ionic liquid (IL). Various DESs exerted different effects on the synthesis of (R)-2-octanol. Choline chloride/ethylene glycol (ChCl/EG) exhibited good biocompatibility and could moderately increase the cell membrane permeability thus leading to the better results. Adding ChCl/EG increased the optimal substrate concentration from 40 mM to 60 mM and the product e.e. kept above 99.9%. To further improve the reaction efficiency, water-immiscible ILs were introduced to the reaction system and an enhanced substrate concentration (1.5 M) was observed with C4MIM·PF6. Additionally, the cells manifested good operational stability in the reaction system. Thus, the efficient biocatalytic process with ChCl/EG and C4MIM·PF6 was promising for efficient synthesis of (R)-2-octanol.

Combination of deep eutectic solvent and ionic liquid to improve biocatalytic reduction of 2-octanone with Acetobacter pasteurianus GIM1.158 cell.

PubMed

Xu, Pei; Du, Peng-Xuan; Zong, Min-Hua; Li, Ning; Lou, Wen-Yong

2016-05-17

The efficient anti-Prelog asymmetric reduction of 2-octanone with Acetobacter pasteurianus GIM1.158 cells was successfully performed in a biphasic system consisting of deep eutectic solvent (DES) and water-immiscible ionic liquid (IL). Various DESs exerted different effects on the synthesis of (R)-2-octanol. Choline chloride/ethylene glycol (ChCl/EG) exhibited good biocompatibility and could moderately increase the cell membrane permeability thus leading to the better results. Adding ChCl/EG increased the optimal substrate concentration from 40 mM to 60 mM and the product e.e. kept above 99.9%. To further improve the reaction efficiency, water-immiscible ILs were introduced to the reaction system and an enhanced substrate concentration (1.5 M) was observed with C4MIM·PF6. Additionally, the cells manifested good operational stability in the reaction system. Thus, the efficient biocatalytic process with ChCl/EG and C4MIM·PF6 was promising for efficient synthesis of (R)-2-octanol.

Microbial communities associated with wet flue gas desulfurization systems

PubMed Central

Brown, Bryan P.; Brown, Shannon R.; Senko, John M.

2012-01-01

Flue gas desulfurization (FGD) systems are employed to remove SOx gasses that are produced by the combustion of coal for electric power generation, and consequently limit acid rain associated with these activities. Wet FGDs represent a physicochemically extreme environment due to the high operating temperatures and total dissolved solids (TDS) of fluids in the interior of the FGD units. Despite the potential importance of microbial activities in the performance and operation of FGD systems, the microbial communities associated with them have not been evaluated. Microbial communities associated with distinct process points of FGD systems at several coal-fired electricity generation facilities were evaluated using culture-dependent and -independent approaches. Due to the high solute concentrations and temperatures in the FGD absorber units, culturable halothermophilic/tolerant bacteria were more abundant in samples collected from within the absorber units than in samples collected from the makeup waters that are used to replenish fluids inside the absorber units. Evaluation of bacterial 16S rRNA genes recovered from scale deposits on the walls of absorber units revealed that the microbial communities associated with these deposits are primarily composed of thermophilic bacterial lineages. These findings suggest that unique microbial communities develop in FGD systems in response to physicochemical characteristics of the different process points within the systems. The activities of the thermophilic microbial communities that develop within scale deposits could play a role in the corrosion of steel structures in FGD systems. PMID:23226147

Integrated photooxidative-extractive desulfurization system for fuel oil using Cu, Fe and Cu-Fe/TiO2 and eutectic based ionic liquids: Effect of calcination temperature and duration

NASA Astrophysics Data System (ADS)

Zaid, Hayyiratul Fatimah Mohd; Kait, Chong Fai; Mutalib, Mohamed Ibrahim Abdul

2014-10-01

Photocatalyts TiO2 doped with Cu, Fe and Cu-Fe metal at different calcination temperature and duration were successfully prepared and characterized. Photocatalytic oxidative desulfurization of model oil containing dibenzothiophene as the sulfur compound (100 ppm) using the prepared photocatalyst was investigated. The photocatalyst calcined at 500°C and duration of 1 h showed the best performance.

Apparatus and method for the desulfurization of petroleum by bacteria

DOEpatents

Lizama, H.M.; Scott, T.C.; Scott, C.D.

1995-10-17

A method is described for treating petroleum with anaerobic microorganisms acting as biocatalysts that can remove sulfur atoms from hydrocarbon molecules, under anaerobic conditions, and then convert the sulfur atoms to hydrogen sulfide. The microorganisms utilized are from the family known as the ``Sulfate Reducing Bacteria``. These bacteria generate metabolic energy from the oxidation of organic compounds, but use oxidized forms of sulfur as an electron acceptor. Because the biocatalyst is present in the form of bacteria in an aqueous suspension, whereas the reacting substrate consists of hydrocarbon molecules in an organic phase, the actual desulfurization reaction takes place at the aqueous-organic interphase. To ensure adequate interfacial contacting and mass transfer, a biphasic electrostatic bioreactor system is utilized. The bioreactor is utilized to disperse and recoalesce a biocatalyst contained in the aqueous liquid phase into the organic liquid phase containing the sulfur. High-intensity electrical fields rupture the aqueous drops into a plurality of microdroplets and induce continuous coalescence and redispersion as the microdroplets travel through the organic phase, thus increasing surface area. As the aqueous microdroplets progress through the organic phase, the biocatalyst then reacts with the sulfur to produce hydrogen sulfide which is then removed from the bioreactor. The organic liquid, now free of the sulfur, is ready for immediate use or further processing. 5 figs.

Synthesis of 1,2-cis-2-C-branched aryl-C-glucosides via desulfurization of carbohydrate based hemithioacetals

PubMed Central

Mebrahtu, Fanuel M; Manana, Mandlenkosi M; Madumo, Kagiso; Sokamisa, Mokela S

2015-01-01

Summary 1-C and 2-C-branched carbohydrates are present as substructures in a number of biologically important compounds. Although the synthesis of such carbohydrate derivatives is extensively studied, the synthesis of 1,2-cis-2-C-branched C-, S-, and N-glycosides is less explored. In this article a synthetic strategy for the synthesis of 1,2-cis-2-C-branched-aryl-C-glucosides is reported via a hydrogenolytic desulfurization of suitably orientated carbohydrate based hemithioacetals. 1,2-cis-2-Hydroxymethyl and 2-carbaldehyde of aryl-C-glucosides have been synthesized using the current strategy in very good yields. The 2-carbaldehyde-aryl-C-glucosides have been identified as suitable substrates for the stereospecific preparation of 2,3-unsaturated-aryl-C-glycosides (Ferrier products). PMID:26124859

Ca removal and Mg recovery from flue gas desulfurization (FGD) wastewater by selective precipitation.

PubMed

Xia, Min; Ye, Chunsong; Pi, Kewu; Liu, Defu; Gerson, Andrea R

2017-11-01

Selective removal of Ca and recovery of Mg by precipitation from flue gas desulfurization (FGD) wastewater has been investigated. Thermodynamic analysis of four possible additives, Na 2 CO 3 , Na 2 C 2 O 4 , NaF and Na 2 SO 4 , indicated that both carbonate and oxalate could potentially provide effective separation of Ca via precipitation from Mg in FGD wastewater. However, it was found experimentally that the carbonate system was not as effective as oxalate in this regard. The oxalate system performed considerably better, with Ca removal efficiency of 96% being obtained, with little Mg inclusion at pH 6.0 when the dosage was ×1.4 the stoichiometric requirement. On this basis, the subsequent recovery process for Mg was carried out using NaOH with two-step precipitation. The product was confirmed to be Mg(OH) 2 (using X-ray diffraction and thermo gravimetric analysis) with elemental analysis suggesting a purity of 99.3 wt.%.

Investigation of a mercury speciation technique for flue gas desulfurization materials.

PubMed

Lee, Joo-Youp; Cho, Kyungmin; Cheng, Lei; Keener, Tim C; Jegadeesan, Gautham; Al-Abed, Souhail R

2009-08-01

Most of the synthetic gypsum generated from wet flue gas desulfurization (FGD) scrubbers is currently being used for wallboard production. Because oxidized mercury is readily captured by the wet FGD scrubber, and coal-fired power plants equipped with wet scrubbers desire to benefit from the partial mercury control that these systems provide, some mercury is likely to be bound in with the FGD gypsum and wallboard. In this study, the feasibility of identifying mercury species in the FGD gypsum and wallboard samples was investigated using a large sample size thermal desorption method. Potential candidates of pure mercury standards including mercuric chloride (HgCl2), mercurous chloride (Hg2Cl2), mercury oxide (HgO), mercury sulfide (HgS), and mercuric sulfate (HgSO4) were analyzed to compare their results with those obtained from FGD gypsum and dry wallboard samples. Although any of the thermal evolutionary curves obtained from these pure mercury standards did not exactly match with those of the FGD gypsum and wallboard samples, it was identified that Hg2Cl2 and HgCl2 could be candidates. An additional chlorine analysis from the gypsum and wallboard samples indicated that the chlorine concentrations were approximately 2 orders of magnitude higher than the mercury concentrations, suggesting possible chlorine association with mercury.

Attapulgite-CeO2/MoS2 ternary nanocomposite for photocatalytic oxidative desulfurization

NASA Astrophysics Data System (ADS)

Li, Xiazhang; Zhang, Zuosong; Yao, Chao; Lu, Xiaowang; Zhao, Xiaobing; Ni, Chaoying

2016-02-01

Novel attapulgite(ATP)-CeO2/MoS2 ternary nanocomposites were synthesized by microwave assisted assembly method. The structures of the nanocomposites were characterized by XRD, FT-IR, UV-vis, XPS and in situ TEM. The photocatalytic activities of ATP-CeO2/MoS2 composites were investigated by degradating dibenzothiophene (DBT) in gasoline under visible light irradiation. The effect of the mass ratio of CeO2 to MoS2 on photocatalytic activity was investigated. The results indicate that the three-dimensional network structure is firmly constructed by ATP skeleton, CeO2 particles and MoS2 nanosheet which effectively increase the surface area of the composites and promote the separation of electrons and holes by resulting electronic transmission channels of multi-channel in space. The degradation rate of DBT can reach 95% under 3 h irradiation when the mass ratio of CeO2/MoS2 is 4/10. A plausible mechanism for the photocatalytic oxidative desulfurization of this nanocomposite is put forward.

Investigation on mercury reemission from limestone-gypsum wet flue gas desulfurization slurry.

PubMed

Chen, Chuanmin; Liu, Songtao; Gao, Yang; Liu, Yongchao

2014-01-01

Secondary atmospheric pollutions may result from wet flue gas desulfurization (WFGD) systems caused by the reduction of Hg(2+) to Hg(0) and lead to a damping of the cobenefit mercury removal efficiency by WFGD systems. The experiment on Hg(0) reemission from limestone-gypsum WFGD slurry was carried out by changing the operating conditions such as the pH, temperature, Cl(-) concentrations, and oxygen concentrations. The partitioning behavior of mercury in the solid and liquid byproducts was also discussed. The experimental results indicated that the Hg(0) reemission rate from WFGD slurry increased as the operational temperatures and pH values increased. The Hg(0) reemission rates decreased as the O2 concentration of flue gas and Cl(-) concentration of WFGD slurry increased. The concentrations of O2 in flue gas have an evident effect on the mercury retention in the solid byproducts. The temperature and Cl(-) concentration have a slight effect on the mercury partitioning in the byproducts. No evident relation was found between mercury retention in the solid byproducts and the pH. The present findings could be valuable for industrial application of characterizing and optimizing mercury control in wet FGD systems.

Investigation on Mercury Reemission from Limestone-Gypsum Wet Flue Gas Desulfurization Slurry

PubMed Central

Liu, Songtao; Liu, Yongchao

2014-01-01

Secondary atmospheric pollutions may result from wet flue gas desulfurization (WFGD) systems caused by the reduction of Hg2+ to Hg0 and lead to a damping of the cobenefit mercury removal efficiency by WFGD systems. The experiment on Hg0 reemission from limestone-gypsum WFGD slurry was carried out by changing the operating conditions such as the pH, temperature, Cl− concentrations, and oxygen concentrations. The partitioning behavior of mercury in the solid and liquid byproducts was also discussed. The experimental results indicated that the Hg0 reemission rate from WFGD slurry increased as the operational temperatures and pH values increased. The Hg0 reemission rates decreased as the O2 concentration of flue gas and Cl− concentration of WFGD slurry increased. The concentrations of O2 in flue gas have an evident effect on the mercury retention in the solid byproducts. The temperature and Cl− concentration have a slight effect on the mercury partitioning in the byproducts. No evident relation was found between mercury retention in the solid byproducts and the pH. The present findings could be valuable for industrial application of characterizing and optimizing mercury control in wet FGD systems. PMID:24737981

Ionic liquids screening for desulfurization of natural gasoline by liquid-liquid extraction.

PubMed

Likhanova, Natalya V; Guzmán-Lucero, Diego; Flores, Eugenio A; García, Paloma; Domínguez-Aguilar, Marco A; Palomeque, Jorge; Martínez-Palou, Rafael

2010-11-01

Seventy five ionic liquids (ILs) were tested as a sequestering agent of sulfured compounds in natural gasoline (NG). Desulphurization of NG was performed by means of liquid-liquid extraction method at room temperature and atmospheric pressure. Experimental ILs containing imidazolium, pyridinium, and ammonium cations along with organic and inorganic anions were synthesized conventionally and under microwave and sonochemical conditions. The effect of the molecular structure of ILs on the desulfurization efficiency of NG with high sulfur content was evaluated. Analysis indicated that the anion type played a more important role than the cation on the desulphurization process. ILs based on halogen-ferrates and halogen-aluminates exhibited the highest efficiency in sulfur removal, and their efficiency is further improved when there is an excess of metallic salt in a ratio of at least 1:1.3 during the synthesis of the corresponding IL. An explanation for the ability of metallic ILs to remove sulfur-containing compounds from natural gasoline based on the ratio of the ionic charge to the atomic radius is proposed. Furthermore, a method to recover and reuse water-sensitive to halogenated precursors is described.

Integrated process design for biocatalytic synthesis by a Leloir Glycosyltransferase: UDP-glucose production with sucrose synthase.

PubMed

Schmölzer, Katharina; Lemmerer, Martin; Gutmann, Alexander; Nidetzky, Bernd

2017-04-01

Nucleotide sugar-dependent ("Leloir") glycosyltransferases (GTs), represent a new paradigm for the application of biocatalytic glycosylations to the production of fine chemicals. However, it remains to be shown that GT processes meet the high efficiency targets of industrial biotransformations. We demonstrate in this study of uridine-5'-diphosphate glucose (UDP-glc) production by sucrose synthase (from Acidithiobacillus caldus) that a holistic process design, involving coordinated development of biocatalyst production, biotransformation, and downstream processing (DSP) was vital for target achievement at ∼100 g scale synthesis. Constitutive expression in Escherichia coli shifted the recombinant protein production mainly to the stationary phase and enhanced the specific enzyme activity to a level (∼480 U/g cell dry weight ) suitable for whole-cell biotransformation. The UDP-glc production had excellent performance metrics of ∼100 g product /L, 86% yield (based on UDP), and a total turnover number of 103 g UDP-glc /g cell dry weight at a space-time yield of 10 g/L/h. Using efficient chromatography-free DSP, the UDP-glc was isolated in a single batch with ≥90% purity and in 73% isolated yield. Overall, the process would allow production of ∼0.7 kg of isolated product/L E. coli bioreactor culture, thus demonstrating how integrated process design promotes the practical use of a GT conversion. Biotechnol. Bioeng. 2017;114: 924-928. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Integrated photooxidative extractive deep desulfurization using metal doped TiO2 and eutectic based ionic liquid

NASA Astrophysics Data System (ADS)

Zaid, Hayyiratul Fatimah Mohd; Kait, Chong Fai; Mutalib, Mohamed Ibrahim Abdul

2016-11-01

A series of metal doped TiO2 namely Fe/TiO2, Cu/TiO2 and Cu-Fe/TiO2 were synthesized and characterized, to be used as a photocatalyst in the integrated photooxidative extractive deep desulfurization for model oil (dodecane) and diesel fuel. The order of the photocatalytic activity was Cu-Fe/TiO2 followed by Cu/TiO2 and then Fe/TiO2. Cu-Fe/TiO2 was an effective photocatalyst for sulfur conversion at ambient atmospheric pressure. Hydrogen peroxide was used as the source of oxidant and eutectic-based ionic liquid as the extractant. Sulfur conversion in model oil reached 100%. Removal of sulfur from model oil was done by two times extraction with a removal of 97.06% in the first run and 2.94% in the second run.

Scalable continuous flow synthesis of ZnO nanorod arrays in 3-D ceramic honeycomb substrates for low-temperature desulfurization

DOE PAGES

Wang, Sibo; Wu, Yunchao; Miao, Ran; ...

2017-07-26

Scalable and cost-effective synthesis and assembly of technologically important nanostructures in three-dimensional (3D) substrates hold keys to bridge the demonstrated nanotechnologies in academia with industrially relevant scalable manufacturing. In this paper, using ZnO nanorod arrays as an example, a hydrothermal-based continuous flow synthesis (CFS) method is successfully used to integrate the nano-arrays in multi-channeled monolithic cordierite. Compared to the batch process, CFS enhances the average growth rate of nano-arrays by 125%, with the average length increasing from 2 μm to 4.5 μm within the same growth time of 4 hours. The precursor utilization efficiency of CFS is enhanced by 9more » times compared to that of batch process by preserving the majority of precursors in recyclable solution. Computational fluid dynamic simulation suggests a steady-state solution flow and mass transport inside the channels of honeycomb substrates, giving rise to steady and consecutive growth of ZnO nano-arrays with an average length of 10 μm in 12 h. The monolithic ZnO nano-array-integrated cordierite obtained through CFS shows enhanced low-temperature (200 °C) desulfurization capacity and recyclability in comparison to ZnO powder wash-coated cordierite. This can be attributed to exposed ZnO {101¯0} planes, better dispersion and stronger interactions between sorbent and reactant in the ZnO nanorod arrays, as well as the sintering-resistance of nano-array configurations during sulfidation–regeneration cycles. Finally, with the demonstrated scalable synthesis and desulfurization performance of ZnO nano-arrays, a promising, industrially relevant integration strategy is provided to fabricate metal oxide nano-array-based monolithic devices for various environmental and energy applications.« less

Scalable continuous flow synthesis of ZnO nanorod arrays in 3-D ceramic honeycomb substrates for low-temperature desulfurization

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

Wang, Sibo; Wu, Yunchao; Miao, Ran

Scalable and cost-effective synthesis and assembly of technologically important nanostructures in three-dimensional (3D) substrates hold keys to bridge the demonstrated nanotechnologies in academia with industrially relevant scalable manufacturing. In this paper, using ZnO nanorod arrays as an example, a hydrothermal-based continuous flow synthesis (CFS) method is successfully used to integrate the nano-arrays in multi-channeled monolithic cordierite. Compared to the batch process, CFS enhances the average growth rate of nano-arrays by 125%, with the average length increasing from 2 μm to 4.5 μm within the same growth time of 4 hours. The precursor utilization efficiency of CFS is enhanced by 9more » times compared to that of batch process by preserving the majority of precursors in recyclable solution. Computational fluid dynamic simulation suggests a steady-state solution flow and mass transport inside the channels of honeycomb substrates, giving rise to steady and consecutive growth of ZnO nano-arrays with an average length of 10 μm in 12 h. The monolithic ZnO nano-array-integrated cordierite obtained through CFS shows enhanced low-temperature (200 °C) desulfurization capacity and recyclability in comparison to ZnO powder wash-coated cordierite. This can be attributed to exposed ZnO {101¯0} planes, better dispersion and stronger interactions between sorbent and reactant in the ZnO nanorod arrays, as well as the sintering-resistance of nano-array configurations during sulfidation–regeneration cycles. Finally, with the demonstrated scalable synthesis and desulfurization performance of ZnO nano-arrays, a promising, industrially relevant integration strategy is provided to fabricate metal oxide nano-array-based monolithic devices for various environmental and energy applications.« less

Surface coal mine land reclamation using a dry flue gas desulfurization product: Short-term and long-term water responses.

PubMed

Chen, Liming; Stehouwer, Richard; Tong, Xiaogang; Kost, Dave; Bigham, Jerry M; Dick, Warren A

2015-09-01

Abandoned coal-mined lands are a worldwide concern due to their potential negative environmental impacts, including erosion and development of acid mine drainage. A field study investigated the use of a dry flue gas desulfurization product for reclamation of abandoned coal mined land in USA. Treatments included flue gas desulfurization product at a rate of 280 Mg ha(-1) (FGD), FGD at the same rate plus 112 Mg ha(-1) yard waste compost (FGD/C), and conventional reclamation that included 20 cm of re-soil material plus 157 Mg ha(-1) of agricultural limestone (SOIL). A grass-legume sward was planted after treatment applications. Chemical properties of surface runoff and tile water (collected from a depth of 1.2m below the ground surface) were measured over both short-term (1-4 yr) and long-term (14-20 yr) periods following reclamation. The pH of surface runoff water was increased from approximately 3, and then sustained at 7 or higher by all treatments for up to 20 yr, and the pH of tile flow water was also increased and sustained above 5 for 20 yr. Compared with SOIL, concentrations of Ca, S and B in surface runoff and tile flow water were generally increased by the treatments with FGD product in both short- and long-term measurements and concentrations of the trace elements were generally not statistically increased in surface runoff and tile flow water over the 20-yr period. However, concentrations of As, Ba, Cr and Hg were occasionally elevated. These results suggest the use of FGD product for remediating acidic surface coal mined sites can provide effective, long-term reclamation. Copyright © 2015. Published by Elsevier Ltd.

Effect of tungsten on the corrosion behavior of sulfuric acid-resistant steels for flue gas desulfurization system

NASA Astrophysics Data System (ADS)

Ji, Woo-Soo; Jang, Young-Wook; Kim, Jung-Gu

2011-06-01

Flue gas desulfurization systems (FGDs) are operated in severely corrosive environments that cause sulfuric acid dew-point corrosion. The corrosion behavior of low-alloy steels was tested using electrochemical techniques (electrochemical impedance spectroscopy, potentiodynamic tests, potentiostatic tests), and the corrosion products were analyzed by scanning electron microscopy and X-ray photoelectron spectroscopy. The electrochemical results showed that alloying W with small amounts of Sb, Cu, and Co improves the corrosion resistance of steels. The results of surface analyses showed that the surface of the steels alloyed with W consisted of W oxides and higher amounts of Sb and Cu oxides. This suggests that the addition of W promotes the formation of a protective WO3 film, in addition to Sb2O5 and CuO films on the surface.

Combination of deep eutectic solvent and ionic liquid to improve biocatalytic reduction of 2-octanone with Acetobacter pasteurianus GIM1.158 cell

PubMed Central

Xu, Pei; Du, Peng-Xuan; Zong, Min-Hua; Li, Ning; Lou, Wen-Yong

2016-01-01

The efficient anti-Prelog asymmetric reduction of 2-octanone with Acetobacter pasteurianus GIM1.158 cells was successfully performed in a biphasic system consisting of deep eutectic solvent (DES) and water-immiscible ionic liquid (IL). Various DESs exerted different effects on the synthesis of (R)-2-octanol. Choline chloride/ethylene glycol (ChCl/EG) exhibited good biocompatibility and could moderately increase the cell membrane permeability thus leading to the better results. Adding ChCl/EG increased the optimal substrate concentration from 40 mM to 60 mM and the product e.e. kept above 99.9%. To further improve the reaction efficiency, water-immiscible ILs were introduced to the reaction system and an enhanced substrate concentration (1.5 M) was observed with C4MIM·PF6. Additionally, the cells manifested good operational stability in the reaction system. Thus, the efficient biocatalytic process with ChCl/EG and C4MIM·PF6 was promising for efficient synthesis of (R)-2-octanol. PMID:27185089

Fundamental studies of desulfurization processes: reaction of methanethiol on ZnO and Cs/ZnO

NASA Astrophysics Data System (ADS)

Dvorak, Joseph; Jirsak, Tomas; Rodriguez, José A.

2001-05-01

The reaction of methanethiol on ZnO and Cs promoted ZnO surfaces has been studied with synchrotron based photoemission and thermal desorption spectroscopy. On ZnO, methanethiol undergoes selective reaction to produce carbon monoxide (37-58%), methane (23-38%), formaldehyde (12-15%), ethane (1-11%), and a mixture of ethylene and acetylene (3-13%). At low temperatures (<100 K), methanethiol reacts to yield thiolate intermediate bound to Zn 2+ cations. The thiolate is stable to 500 K. Above this temperature, C-S bond cleavage occurs to yield methyl intermediate and atomic S. Carbon is removed from the surface as gaseous products above 500 K, and atomic sulfur remains bound to the zinc sites of the surface. Submonolayer amounts of cesium do not have a significant promotional effect on C-S bond cleavage, whereas Cs multilayers are found to significantly lower the activation barrier for C-S bond cleavage. This study illustrates the chemistry associated with the desulfurization of thiols on a catalytically relevant oxide surface.

The dissolution kinetics of industrial brine sludge wastes from a chlor-alkali industry as a sorbent for wet flue gas desulfurization (FGD).

PubMed

Masilela, E; Lerotholi, L; Seodigeng, T; Rutto, H

2018-02-01

The disposal of industrial brine sludge waste (IBSW) in chlor-alkali plants can be avoided by utilization of IBSW as a sorbent in wet flue gas desulfurization (FGD). The shrinking core model was used to determine the dissolution kinetics of IBSW, which is a vital step in wet FGD. The effects of solid-to-liquid ratio (m/v), temperature, pH, particle size, and stirring speed on the conversion and dissolution rate constant are determined. The conversion and dissolution rate constant decreases as the pH, particle size, and solid-to-liquid ratio are increased and increases as the temperature, concentration of acid, and stirring speed are increased. The sorbents before and after dissolution were characterized using x-ray fluorescence (XRF), x-ray diffraction (XRD), and scanning electron microscopy (SEM). An activation energy of 7.195 kJ/mol was obtained and the product layer diffusion model was found to be the rate-controlling step. The use of industrial brine sludge waste as an alternative sorbent in wet flue gas desulfurization can reduce the amounts of industrial wastes disposed of in landfills. This study has proved that the sorbent can contain up to 91% calcium carbonate and trace amounts of sulfate, magnesium, and so on. This can be used as new sorbent to reduce the amount of sulfur dioxide in the atmosphere and the by-product gypsum can be used in construction, as a plaster ingredient, as a fertilizer, and for soil conditioning. Therefore, the sorbent has both economic and environmental benefits.

Investigation of a mercury speciation technique for flue gas desulfurization materials

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

Lee, J.Y.; Cho K.; Cheng L.

2009-08-15

Most of the synthetic gypsum generated from wet flue gas desulfurization (FGD) scrubbers is currently being used for wallboard production. Because oxidized mercury is readily captured by the wet FGD scrubber, and coal-fired power plants equipped with wet scrubbers desire to benefit from the partial mercury control that these systems provide, some mercury is likely to be bound in with the FGD gypsum and wallboard. In this study, the feasibility of identifying mercury species in the FGD gypsum and wallboard samples was investigated using a large sample size thermal desorption method and samples from power plants in Pennsylvania. Potential candidatesmore » of pure mercury standards including mercuric chloride, mercurous chloride, mercury oxide, mercury sulfide, and mercuric sulfate were analyzed to compare their results with those obtained from FGD gypsum and dry wallboard samples. Although any of the thermal evolutionary curves obtained from these pure mercury standards did not exactly match with those of the FGD gypsum and wallboard samples, it was identified that Hg{sub 2}Cl{sub 2} and HgCl{sub 2} could be candidates. An additional chlorine analysis from the gypsum and wallboard samples indicated that the chlorine concentrations were approximately 2 orders of magnitude higher than the mercury concentrations, suggesting possible chlorine association with mercury. 21 refs., 5 figs., 3 tabs.« less

Use of flue gas desulfurization gypsum for leaching Cd and Pb in reclaimed tidal flat soil.

PubMed

Yang, Ping; Li, Xian; Tong, Ze-Jun; Li, Qu-Sheng; He, Bao-Yan; Wang, Li-Li; Guo, Shi-Hong; Xu, Zhi-Min

2016-04-01

A soil column leaching experiment was conducted to eliminate heavy metals from reclaimed tidal flat soil. Flue gas desulfurization (FGD) gypsum was used for leaching. The highest removal rates of Cd and Pb in the upper soil layers (0-30 cm) were 52.7 and 30.5 %, respectively. Most of the exchangeable and carbonate-bound Cd and Pb were removed. The optimum FGD gypsum application rate was 7.05 kg·m(-2), and the optimum leaching water amount for the application was 217.74 L·m(-2). The application of FGD gypsum (two times) and the extension of the leaching interval time to 20 days increased the heavy metal removal rate in the upper soil layers. The heavy metals desorbed from the upper soil layers were re-adsorbed and fixed in the 30-70 cm soil layers.

Enhanced biocatalytic production of L-cysteine by Pseudomonas sp. B-3 with in situ product removal using ion-exchange resin.

PubMed

Wang, Pu; He, Jun-Yao; Yin, Jiang-Feng

2015-03-01

Bioconversion of DL-2-amino-Δ(2)-thiazoline-4-carboxylic acid (DL-ATC) catalyzed by whole cells of Pseudomonas sp. was successfully applied for the production of L-cysteine. It was found, however, like most whole-cell biocatalytic processes, the accumulated L-cysteine produced obvious inhibition to the activity of biocatalyst and reduced the yield. To improve L-cysteine productivity, an anion exchange-based in situ product removal (ISPR) approach was developed. Several anion-exchange resins were tested to select a suitable adsorbent used in the bioconversion of DL-ATC for the in situ removal of L-cysteine. The strong basic anion-exchange resin 201 × 7 exhibited the highest adsorption capacity for L-cysteine and low adsorption for DL-ATC, which is a favorable option. With in situ addition of 60 g L(-1) resin 201 × 7, the product inhibition can be reduced significantly and 200 mmol L(-1) of DL-ATC was converted to L-cysteine with 90.4 % of yield and 28.6 mmol L(-1 )h(-1) of volumetric productivity. Compared to the bioconversion without the addition of resin, the volumetric productivity of L-cysteine was improved by 2.27-fold using ISPR method.

A novel approach to realize SANI process in freshwater sewage treatment--Use of wet flue gas desulfurization waste streams as sulfur source.

PubMed

Jiang, Feng; Zhang, Liang; Peng, Guo-Liang; Liang, Si-Yun; Qian, Jin; Wei, Li; Chen, Guang-Hao

2013-10-01

SANI (Sulfate reduction, Autotrophic denitrification and Nitrification Integrated) process has been approved to be a sludge-minimized sewage treatment process in warm and coastal cities with seawater supply. In order to apply this sulfur-based process in inland cold areas, wet flue gas desulfurization (FGD) can be simplified and integrated with SANI process, to provide sulfite as electron carrier for sulfur cycle in sewage treatment. In this study, a lab-scale system of the proposed novel process was developed and run for over 200 days while temperature varied between 30 and 5 °C, fed with synthetic FGD wastewaters and sewage. The sulfite-reducing upflow anaerobic sludge bed (SrUASB) reactor, as the major bioreactor of the system, removed 86.9% of organics while the whole system removed 94% of organics even when water temperature decreased to around 10 °C. The bactericidal effect of sulfite was not observed in the SrUASB reactor, while thiosulfate was found accumulated under psychrophilic conditions. The sludge yield of the SrUASB reactor was determined to be 0.095 kg VSS/kg COD, higher than of sulfate reduction process but still much lower than of conventional activated sludge processes. The dominant microbes in the SrUASB reactor were determined as Lactococcus spp. rather than sulfate-reducing bacteria, but sulfite reduction still contributed 85.5% to the organic carbon mineralization in this reactor. Ammonia and nitrate were effectively removed in the aerobic and anoxic filters, respectively. This study confirms the proposed process was promising to achieve sludge-minimized sewage treatment integrating with flue gas desulfurization in inland and cold areas. Copyright © 2013 Elsevier Ltd. All rights reserved.

Characterization of copper oxides, iron oxides, and zinc copper ferrite desulfurization sorbents by X-ray photoelectron spectroscopy and scanning electron microscopy

NASA Astrophysics Data System (ADS)

Siriwardane, Ranjani V.; Poston, James A.

1993-05-01

Characterization of copper oxides, iron oxides, and zinc copper ferrite desulfurization sorbents was performed by X-ray photoelectron spectroscopy and scanning electron microscopy/energy-dispersive spectroscopy at temperatures of 298 to 823 K. Analysis of copper oxides indicated that the satellite structure of the Cu22p region was absent in the Cu(I) state but was present in the Cu(II) state. Reduction of CuO at room temperature was observed when the ion gauge was placed close to the sample. The satellite structure was absent in all the copper oxides at 823 K in vacuum. Differentiation of the oxidation state of copper utilizing both Cu(L 3M 4,5M 4,5) X-ray-induced Auger lines and Cu2p satellite structure, indicated that the copper in zinc copper ferrite was in the + 1 oxidation state at 823 K. This + 1 state of copper was not significantly changed after exposure to H 2, CO, and H 2O. There was an increase in Cu/Zn ratio and a decrease in Fe/Zn ratio on the surface of zinc copper ferrite at 823 K compared to that at room temperature. These conditions of copper offered the best sulfidation equilibrium for the zinc copper ferrite desulfurization sorbent. Analysis of iron oxides indicated that there was some reduction of both Fe 2O 3 and FeO at 823K. The iron in zinc copper ferrite was similar to that of Fe 2O 3 at room temperature but there was some reduction of this Fe(III) state to Fe(II) at 823 K. This reduction was more enhanced in the presence of H 2 and CO. Reduction to Fe(II) may not be desirable for the lifetime of the sorbent.

Can microbes economically remove sulfur

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

Fox, J.L.

Researchers have reported that refiners who now rely on costly physic-chemical procedures to desulfurize petroleum will soon have an alternative microbial-enzyme-based approach to this process. This new approach is still under development and considerable number chemical engineering problems need to be solved before this process is ready for large-scale use. This paper reviews the several research projects dedicated solving the problems that keep a biotechnology-based alternative from competing with chemical desulfurization.

Oxidative desulfurization-fluorination of thioethers. Application for the synthesis of fluorinated nitrogen containing building blocks.

PubMed

Hugenberg, Verena; Fröhlich, Roland; Haufe, Günter

2010-12-21

An oxidative desulfurization-fluorination protocol has been used to synthesize (2S)-2-(difluoromethyl)-N-tosylpyrrolidine (6a) and (2S)-2-(trifluoromethyl)-N-tosylpyrrolidine (7a) from the (2S)-prolinol-derived (2S)-2-(4-chlorophenylthiomethyl)-N-tosylpyrrolidine (9) or (2S)-2-(dithian-2-yl)-N-tosylpyrrolidine (5). Efforts to prepare 3,3-difluoroalanine similarly from an N-protected S-aryl-cysteine ester 17 gave only traces of the target compound 18. Instead, an unique N-(α,α-difluorobenzyl)-N-α',α'-dibromoglycine ester 19 was formed by an unprecedented sequence of reaction steps. A plausible mechanism is suggested involving a sulfur-assisted deoxygenation-difluorination of an imino oxygen and a haloform reaction like carbon-carbon bond fission as key-steps. Efforts to prepare (2S)-2-(fluoromethyl)-N-tosylpyrrolidine (12) from (2S)-N-tosylprolinol (3) by treatment with Fluolead™ (1-tert-butyl-4-trifluorosulfanyl-3,5-dimethylbenzene) gave only 5% of the target compound, but 95% of (3R)-3-fluoro-N-tosylpiperidine (11a) by ring enlargement.

Rate-limiting step analysis of the microbial desulfurization of dibenzothiophene in a model oil system

PubMed Central

Abin-Fuentes, Andres; Leung, James C.; Mohamed, Magdy El-Said; Wang, Daniel IC; Prather, Kristala LJ

2014-01-01

A mechanistic analysis of the various mass transport and kinetic steps in the microbial desulfurization of dibenzothiophene (DBT) by Rhodococcus erythropolis IGTS8 in a model biphasic (oil-water), small-scale system was performed. The biocatalyst was distributed into three populations, free cells in the aqueous phase, cell aggregates and oil-adhered cells, and the fraction of cells in each population was measured. The power input per volume (P/V) and the impeller tip speed (vtip) were identified as key operating parameters in determining whether the system is mass transport controlled or kinetically controlled. Oil-water DBT mass transport was found to not be limiting under the conditions tested. Experimental results at both the 100 mL and 4L (bioreactor) scales suggest that agitation leading to P/V greater than 10,000 W/ m3 and/or vtip greater than 0.67 m/s is sufficient to overcome the major mass transport limitation in the system, which was the diffusion of DBT within the biocatalyst aggregates. PMID:24284557

Influence of surface phenomena in oxidative desulfurization with WOx/ZrO2 catalysts

NASA Astrophysics Data System (ADS)

Torres-García, E.; Canizal, G.; Velumani, S.; Ramírez-Verduzco, L. F.; Murrieta-Guevara, F.; Ascencio, J. A.

2004-12-01

Oil refinery related catalysis, particularly hydro desulfurization is viewed as a mature technology, but still we view that more efforts have to be made to boost the efficiency of the existing catalysts. So in this article we report the use of WOx/ZrO2 catalysts for the oxidation of dibenzothiophene (DBT) as a more effective material in nanometer scales. The WOx/ZrO2 samples were prepared by solid impregnation of ZrO2-x(OH)2x with ammonium metatungstate solution maintaining the pH at 10. Detailed structural and surface morphological analyses were carried out using Raman spectroscopy and Atomic force microscopy. In order to understand the catalytic activity which is largely influenced by the surface morphology, an interpretation based on the experimental results is given. The results showed an important correlation between the catalytic efficiency with the morphology of the surface which is identified as arrays of planes with steps of around 10 nm with the structures showing faceting with a preferential angle of 90°. It was established that when the number of W atoms in the surface increase the catalytic efficiency also increases. Thus we conclude that the material efficiency as a catalyst is directly related with the surface structure.

Heterogeneous oxidative desulfurization of diesel fuel catalyzed by mesoporous polyoxometallate-based polymeric hybrid.

PubMed

Yang, Huawei; Jiang, Bin; Sun, Yongli; Zhang, Luhong; Huang, Zhaohe; Sun, Zhaoning; Yang, Na

2017-07-05

In this work, the simple preparation of novel polymer supported polyoxometallates (POMs) catalysts has been reported. Soluble task-specific cross-linked poly (ionic liquid) (PIL) was prepared with N,​N-​dimethyl-​dodecyl-​(4-​vinylbenzyl) ammonium chloride and divinylbenzene as co-monomers. The as-prepared cationic PILs were assembled with different commercial POMs to form the interlinked mesoporous catalysts, and the formation mechanism was provided. The catalytic oxidation activities of the catalysts were closely related to the formation pathway of their corresponding peroxide active species. The catalyst with H 2 W 12 O 42 10- as counterion, which exhibited the best activity in the oxidation of benzothiophene (BT) and dibenzothiophene (DBT) to sulfones in model oil with hydrogen peroxide (H 2 O 2 , 30wt%) as oxidant, was characterized by different techniques and systematically studied for its sulfur removal performance. As for the oxidative desulfurization of a real diesel, it was observed that almost all of the original sulfur compounds could be completely converted, and the catalyst could be reused for at least eight cycles without noticeable changes in both catalytic activity and chemical structure. In the end, a catalytic mechanism was put forward with the assistant of Raman analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Technical Support to SBIR Phase II Project: Improved Conversion of Cellulose Waste to Ethanol Using a Dual Bioreactor System: Cooperative Research and Development Final Report, CRADA Number CRD-08-310

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

Zhang, M.

2013-04-01

Over-dependence on fossil fuel has spurred research on alternative energy. Inedible plant materials such as grass and corn stover represent abundant renewable natural resources that can be transformed into biofuel. Problems in enzymatic conversion of biomass to sugars include the use of incomplete synergistic enzymes, end-product inhibition, and adsorption and loss of enzymes necessitating their use in large quantities. Technova Corporation will develop a defined consortium of natural microorganisms that will efficiently break down biomass to energy-rich soluble sugars, and convert them to cleaner-burning ethanol fuel. The project will also develop a novel biocatalytic hybrid reactor system dedicated to thismore » bioprocess, which embodies recent advances in nanotechnology. NREL will participate to develop a continuous fermentation process.« less

Projections of Demand for Waterborne Transportation, Ohio River Basin, 1980, 1990, 2000, 2020, 2040. Volume 14. Group XII. Rubber, Plastic, Nonmetallic Mineral Products, Nec.

DTIC Science & Technology

1980-12-01

thousand tons by the year 2040. Much of this increased consumption will be lime used in flue gas desulfurization . A. Market Areas In addition to local...increased consumption will result from lime consumed in lime and limestone flue gas desulfur - ization (FGD) installation processes. During the period 2000...is the use of lime and limestone in flue gas desulfu- rization processes. Lime scrubbers for power plants and other industrial plants have also

Chemical and physical properties of dry flue gas desulfurization products.

PubMed

Kost, David A; Bigham, Jerry M; Stehouwer, Richard C; Beeghly, Joel H; Fowler, Randy; Traina, Samuel J; Wolfe, William E; Dick, Warren A

2005-01-01

Beneficial and environmentally safe recycling of flue gas desulfurization (FGD) products requires detailed knowledge of their chemical and physical properties. We analyzed 59 dry FGD samples collected from 13 locations representing four major FGD scrubbing technologies. The chemistry of all samples was dominated by Ca, S, Al, Fe, and Si and strong preferential partitioning into the acid insoluble residue (i.e., coal ash residue) was observed for Al, Ba, Be, Cr, Fe, Li, K, Pb, Si, and V. Sulfur, Ca, and Mg occurred primarily in water- or acid-soluble forms associated with the sorbents or scrubber reaction products. Deionized water leachates (American Society for Testing and Materials [ASTM] method) and dilute acetic acid leachates (toxicity characteristic leaching procedure [TCLP] method) had mean pH values of >11.2 and high mean concentrations of S primarily as SO(2-)4 and Ca. Concentrations of Ag, As, Ba, Cd, Cr, Hg, Pb, and Se (except for ASTM Se in two samples) were below drinking water standards in both ASTM and TCLP leachates. Total toxicity equivalents (TEQ) of dioxins, for two FGD products used for mine reclamation, were 0.48 and 0.53 ng kg(-1). This was similar to the background level of the mine spoil (0.57 ng kg(-1)). The FGD materials were mostly uniform in particle size. Specific surface area (m2 g(-1)) was related to particle size and varied from 1.3 for bed ash to 9.5 for spray dryer material. Many of the chemical and physical properties of these FGD samples were associated with the quality of the coal rather than the combustion and SO2 scrubbing processes used.

Manufacture of ammonium sulfate fertilizer from gypsum-rich byproduct of flue gas desulfurization - A prefeasibility cost estimate

USGS Publications Warehouse

Chou, I.-Ming; Rostam-Abadi, M.; Lytle, J.M.; Achorn, F.P.

1996-01-01

Costs for constructing and operating a conceptual plant based on a proposed process that converts flue gas desulfurization (FGD)-gypsum to ammonium sulfate fertilizer has been calculated and used to estimate a market price for the product. The average market price of granular ammonium sulfate ($138/ton) exceeds the rough estimated cost of ammonium sulfate from the proposed process ($111/ ton), by 25 percent, if granular size ammonium sulfate crystals of 1.2 to 3.3 millimeters in diameters can be produced by the proposed process. However, there was at least ??30% margin in the cost estimate calculations. The additional costs for compaction, if needed to create granules of the required size, would make the process uneconomical unless considerable efficiency gains are achieved to balance the additional costs. This study suggests the need both to refine the crystallization process and to find potential markets for the calcium carbonate produced by the process.

Biotechnological production of fucosylated human milk oligosaccharides: Prokaryotic fucosyltransferases and their use in biocatalytic cascades or whole cell conversion systems.

PubMed

Petschacher, Barbara; Nidetzky, Bernd

2016-10-10

Human milk oligosaccharides (HMOs) constitute a class of complex carbohydrates unique to mother's milk and are strongly correlated to the health benefits of breastfeeding in infants. HMOs are important as functional ingredients of advanced infant formula and have attracted broad interest for use in health-related human nutrition. About 50% of the HMOs structures contain l-fucosyl residues, which are introduced into nascent oligosaccharides by enzymatic transfer from GDP-l-fucose. To overcome limitation in the current availability of fucosylated HMOs, biotechnological approaches for their production have been developed. Functional expression of the fucosyltransferase(s) and effective supply of GDP-l-fucose, respectively, are both bottlenecks of the biocatalytic routes of synthesis. Strategies of in vitro and in vivo production of fucosylated HMOs are reviewed here. Besides metabolic engineering for enhanced HMO production in whole cells, the focus is on the characteristics and the heterologous overexpression of prokaryotic α1,2- and α1,3/4-fucosyltransferases. Up to 20g/L of fucosylated HMOs were obtained in optimized production systems. Optimized expression enabled recovery of purified fucosyltransferases in a yield of up to 45mg/L culture for α1,2-fucosyltransferases and of up to 200mg protein/L culture for α1,3/4-fucosyltransferases. Copyright © 2016 Elsevier B.V. All rights reserved.

Improving the Desulfurization Degree of High-Grade Nickel Matte via a Two-Step Oxidation Roasting Process

NASA Astrophysics Data System (ADS)

Xi, Zhao; Wang, Zhixing; Li, Xinhai; Guo, Huajun; Yan, Guochun; Wang, Jiexi

2018-05-01

Generally, sulfur elimination from nickel matte was incomplete in the one-step oxidation roasting process. In this work, X-ray diffraction, scanning electron microscopy/energy-dispersive X-ray spectroscopy, and chemical analysis of the roasted products were carried out to explain this phenomenon. The results indicated that the melting of heazlewoodite was the main limiting factor. Thereafter, the oxidation mechanism of high-grade nickel matte from room temperature to 1000 °C was studied. It was found that the transformation from heazlewoodite (Ni3S2) to nickel sulfide (NiS) took place from 400 °C to 520 °C. Considering that the melting temperature of NiS was much higher than that of Ni3S2, a low-temperature roasting step was suggested to suppress the melting of heazlewoodite. Under the optimum conditions (520 °C for 120 minutes followed by 800 °C for 80 minutes), the degree of desulfurization reached 99.52 pct. These results indicated that the two-step oxidation roasting method could be a promising process for producing low-sulfur calcine from high-grade nickel matte.

Analysis of Bacterial Community Structure in Sulfurous-Oil-Containing Soils and Detection of Species Carrying Dibenzothiophene Desulfurization (dsz) Genes

PubMed Central

Duarte, Gabriela Frois; Rosado, Alexandre Soares; Seldin, Lucy; de Araujo, Welington; van Elsas, Jan Dirk

2001-01-01

The selective effects of sulfur-containing hydrocarbons, with respect to changes in bacterial community structure and selection of desulfurizing organisms and genes, were studied in soil. Samples taken from a polluted field soil (A) along a concentration gradient of sulfurous oil and from soil microcosms treated with dibenzothiophene (DBT)-containing petroleum (FSL soil) were analyzed. Analyses included plate counts of total bacteria and of DBT utilizers, molecular community profiling via soil DNA-based PCR-denaturing gradient gel electrophoresis (PCR-DGGE), and detection of genes that encode enzymes involved in the desulfurization of hydrocarbons, i.e., dszA, dszB, and dszC.Data obtained from the A soil showed no discriminating effects of oil levels on the culturable bacterial numbers on either medium used. Generally, counts of DBT degraders were 10- to 100-fold lower than the total culturable counts. However, PCR-DGGE showed that the numbers of bands detected in the molecular community profiles decreased with increasing oil content of the soil. Analysis of the sequences of three prominent bands of the profiles generated with the highly polluted soil samples suggested that the underlying organisms were related to Actinomyces sp., Arthrobacter sp., and a bacterium of uncertain affiliation. dszA, dszB, and dszC genes were present in all A soil samples, whereas a range of unpolluted soils gave negative results in this analysis. Results from the study of FSL soil revealed minor effects of the petroleum-DBT treatment on culturable bacterial numbers and clear effects on the DBT-utilizing communities. The molecular community profiles were largely stable over time in the untreated soil, whereas they showed a progressive change over time following treatment with DBT-containing petroleum. Direct PCR assessment revealed the presence of dszB-related signals in the untreated FSL soil and the apparent selection of dszA- and dszC-related sequences by the petroleum-DBT treatment

Sodic soil properties and sunflower growth as affected by byproducts of flue gas desulfurization.

PubMed

Wang, Jinman; Bai, Zhongke; Yang, Peiling

2012-01-01

The main component of the byproducts of flue gas desulfurization (BFGD) is CaSO(4), which can be used to improve sodic soils. The effects of BFGD on sodic soil properties and sunflower growth were studied in a pot experiment. The experiment consisted of eight treatments, at four BFGD rates (0, 7.5, 15 and 22.5 t ha(-1)) and two leaching levels (750 and 1200 m(3) ha(-1)). The germination rate and yield of the sunflower increased, and the exchangeable sodium percentage (ESP), pH and total dissolved salts (TDS) in the soils decreased after the byproducts were applied. Excessive BFGD also affected sunflower germination and growth, and leaching improved reclamation efficiency. The physical and chemical properties of the reclaimed soils were best when the byproducts were applied at 7.5 t ha(-1) and water was supplied at 1200 m(3)·ha(-1). Under these conditions, the soil pH, ESP, and TDS decreased from 9.2, 63.5 and 0.65% to 7.8, 2.8 and 0.06%, and the germination rate and yield per sunflower reached 90% and 36.4 g, respectively. Salinity should be controlled by leaching when sodic soils are reclaimed with BFGD as sunflower growth is very sensitive to salinity during its seedling stage.

Adsorptive Desulfurization of Model Gasoline by Using Different Zn Sources Exchanged NaY Zeolites.

PubMed

Rui, Jingwei; Liu, Fei; Wang, Rijie; Lu, Yanfei; Yang, Xiaoxia

2017-02-17

A series of Zn-modified NaY zeolites were prepared by the liquid-phase ion-exchange method with different Zn sources, including Zn(NO₃)₂, Zn(Ac)₂ and ZnSO₄. The samples were tested as adsorbents for removing an organic sulfur compound from a model gasoline fuel containing 1000 ppmw sulfur. Zn(Ac)₂-Y exhibited the best performance for the desulfurization of gasoline at ambient conditions. Combined with the adsorbents' characterization results, the higher adsorption capacity of Zn(Ac)₂-Y is associated with a higher ion-exchange degree. Further, the results demonstrated that the addition of 5 wt % toluene or 1-hexene to the diluted thiophene (TP) solution in cyclohexane caused a large decrease in the removal of TP from the model gasoline fuel. This provides evidence about the competition through the π-complexation between TP and toluene for adsorption on the active sites. The acid-catalyzed alkylation by 1-hexene of TP and the generated complex mixture of bulky alkylthiophenes would adsorb on the surface active sites of the adsorbent and block the pores. The regenerated Zn(Ac)₂-Y adsorbent afforded 84.42% and 66.10% of the initial adsorption capacity after the first two regeneration cycles.

Oxidative desulfurization of benzothiophene and thiophene with WOx/ZrO2 catalysts: effect of calcination temperature of catalysts.

PubMed

Hasan, Zubair; Jeon, Jaewoo; Jhung, Sung Hwa

2012-02-29

Oxidative desulfurization (ODS) of model fuel containing benzothiophene (BT) or thiophene (Th) has been carried out with WO(x)/ZrO2 catalyst, which was calcined at various temperatures. Based on the conversion of BT in the model fuel, it can be shown that the optimum calcination temperature of WOx/ZrO2 catalyst is around 700 °C. The most active catalyst is composed of tetragonal zirconia (ZrO2) with well dispersed polyoxotungstate species and it is necessary to minimize the contents of the crystalline WO3 and monoclinic ZrO2 for a high BT conversion. The oxidation rate was interpreted with the first-order kinetics, and it demonstrated the importance of electron density since the kinetic constant for BT was higher than that for Th even though the BT is larger than Th in size. A WOx/ZrO2 catalyst, treated suitably, can be used as a reusable active catalyst in the ODS. Copyright © 2012 Elsevier B.V. All rights reserved.

Survey of flue gas desulfurization systems: Duck Creek Station, Central Illinois Light Co. Final report, Jul-Dec 1978

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

Laseke, B.A. Jr.

The report presents the results of a survey of operational flue gas desulfurization (FGD) systems on coal-fired utility boilers in the United States. The FGD system installed on Unit 1 at the Duck Creek Station of Central Illinois Light Company is described in terms of design and performance. The system consists of four parallel, wet-limestone, rod-deck scrubber modules designed for 25% capacity each, providing a total sulfur dioxide removal efficiency of 85%. The bottom ash, fly ash, and scrubbing wastes are disposed of in a sludge pond lined with a natural impermeable material. The first module of this four modulemore » FGD system was placed in service on July 1, 1976, and operated intermittently throughout the remainder of the year and for approximately one month in early 1977. On July 23, 1978, the three remaining modules were completed and all four modules were placed in the gas path for treatment of high sulfur flue gas.« less

Biocatalytic ammonolysis of (5S)-4,5-dihydro-1H-pyrrole-1,5-dicarboxylic acid, 1-(1,1-dimethylethyl)-5-ethyl ester: preparation of an intermediate to the dipeptidyl peptidase IV inhibitor Saxagliptin.

PubMed

Gill, Iqbal; Patel, Ramesh

2006-02-01

An efficient biocatalytic method has been developed for the conversion of (5S)-4,5-dihydro-1H-pyrrole-1,5-dicarboxylic acid, 1-(1,1-dimethylethyl)-5-ethyl ester (1) into the corresponding amide (5S)-5-aminocarbonyl-4,5-dihydro-1H-pyrrole-1-carboxylic acid, 1-(1,1-dimethylethyl)ester (2), which is a critical intermediate in the synthesis of the dipeptidyl peptidase IV (DPP4) inhibitor Saxagliptin (3). Candida antartica lipase B mediates ammonolysis of the ester with ammonium carbamate as ammonia donor to yield up to 71% of the amide. The inclusion of Ascarite and calcium chloride as adsorbents for carbon dioxide and ethanol byproducts, respectively, increases the yield to 98%, thereby offering an efficient and practical alternative to chemical routes which yield 57-64%.

Efficient assessment of modified nucleoside stability under conditions of automated oligonucleotide synthesis: characterization of the oxidation and oxidative desulfurization of 2-thiouridine.

PubMed

Sochacka, E

2001-01-01

In order to efficiently assess the chemical stability of modified nucleosides to the reagents and conditions of automated oligonucleotide synthesis, we designed, developed and tested a scheme in which the modified nucleoside, directly attached to a solid support, is exposed to the cyclic chemistry of the instrument. Stability of 2-thiouridine against different oxidizers was investigated. Tertbutyl hydroperoxide (1 M) in anhydrous acetonitrile was a more effective oxidizer for the incorporation of 2-thiouridine into oligonucleotide chains than the same oxidizer in methylene chloride. Carbon tetrachloride/water in the presence of a basic catalyst was superior in maintaining the thiocarbonyl function, but its utility for RNA synthesis has yet to be fully tested, whereas 2-phenylsulfonyloxaziridine was a very efficient reagent for oxidative desulfurization of 2-thiouridine.

Leloir Glycosyltransferases and Natural Product Glycosylation: Biocatalytic Synthesis of the C-Glucoside Nothofagin, a Major Antioxidant of Redbush Herbal Tea

PubMed Central

Bungaruang, Linda; Gutmann, Alexander; Nidetzky, Bernd

2013-01-01

Nothofagin is a major antioxidant of redbush herbal tea and represents a class of bioactive flavonoid-like C-glycosidic natural products. We developed an efficient enzymatic synthesis of nothofagin based on a one-pot coupled glycosyltransferase-catalyzed transformation that involves perfectly selective 3′-C-β-d-glucosylation of naturally abundant phloretin and applies sucrose as expedient glucosyl donor. C-Glucosyltransferase from Oryza sativa (rice) was used for phloretin C-glucosylation from uridine 5′-diphosphate (UDP)-glucose, which was supplied continuously in situ through conversion of sucrose and UDP catalyzed by sucrose synthase from Glycine max (soybean). In an evaluation of thermodynamic, kinetic, and stability parameters of the coupled enzymatic reactions, poor water solubility of the phloretin acceptor substrate was revealed as a major bottleneck of conversion efficiency. Using periodic feed of phloretin controlled by reaction progress, nothofagin concentrations (45 mM; 20 g l−1) were obtained that vastly exceed the phloretin solubility limit (5–10 mM). The intermediate UDP-glucose was produced from catalytic amounts of UDP (1.0 mM) and was thus recycled 45 times in the process. Benchmarked against comparable glycosyltransferase-catalyzed transformations (e.g., on quercetin), the synthesis of nothofagin has achieved intensification in glycosidic product formation by up to three orders of magnitude (μM→mM range). It thus makes a strong case for the application of Leloir glycosyltransferases in biocatalytic syntheses of glycosylated natural products as fine chemicals. PMID:24415961

Comparative study on the corrosion behavior of the cold rolled and hot rolled low-alloy steels containing copper and antimony in flue gas desulfurization environment

NASA Astrophysics Data System (ADS)

Park, S. A.; Kim, J. G.; He, Y. S.; Shin, K. S.; Yoon, J. B.

2014-12-01

The correlation between the corrosion and microstructual characteristics of cold rolled and hot rolled low-alloy steels containing copper and antimony was established. The corrosion behavior of the specimens used in flue gas desulfurization systems was examined by electrochemical and weight loss measurements in an aggressive solution of 16.9 vol % H2SO4 + 0.35 vol % HCl at 60°C, pH 0.3. It has been shown that the corrosion rate of hot rolled steel is lower than that of cold rolled steel. The corrosion rate of cold rolled steel was increased by grain refinement, inclusion formation, and preferred grain orientation.

Process for preparing multilayer enzyme coating on a fiber

DOEpatents

Kim, Jungbae [Richland, WA; Kwak, Ja Hun [Richland, WA; Grate, Jay W [West Richland, WA

2009-11-03

A process for preparing high stability, high activity biocatalytic materials is disclosed and processes for using the same. The process involves coating of a material or fiber with enzymes and enzyme aggregate providing a material or fiber with high biocatalytic activity and stability useful in heterogeneous environments. In one illustrative approach, enzyme "seeds" are covalently attached to polymer nanofibers followed by treatment with a reagent that crosslinks additional enzyme molecules to the seed enzymes forming enzyme aggregates thereby improving biocatalytic activity due to increased enzyme loading and enzyme stability. This approach creates a useful new biocatalytic immobilized enzyme system with potential applications in bioconversion, bioremediation, biosensors, and biofuel cells.

Structural optimization of SadA, an Fe(II)- and α-ketoglutarate-dependent dioxygenase targeting biocatalytic synthesis of N-succinyl-L-threo-3,4-dimethoxyphenylserine.

PubMed

Qin, Hui-Min; Miyakawa, Takuya; Nakamura, Akira; Hibi, Makoto; Ogawa, Jun; Tanokura, Masaru

2014-08-08

L-threo-3,4-Dihydroxyphenylserine (l-DOPS, Droxidopa) is a psychoactive drug and synthetic amino acid precursor that acts as a prodrug to the neurotransmitters. SadA, a dioxygenase from Burkholderia ambifaria AMMD, is an Fe(II)- and α-ketoglutarate (KG)-dependent enzyme that catalyzes N-substituted branched-chain or aromatic l-amino acids. SadA is able to produce N-succinyl-l-threo-3,4-dimethoxyphenylserine (NSDOPS), which is a precursor of l-DOPS, by catalyzing the hydroxylation of N-succinyl-3,4-dimethoxyphenylalanine (NSDOPA). However, the catalytic activity of SadA toward NSDOPS is much lower than that toward N-succinyl branched-chain l-amino acids. Here, we report an improved biocatalytic synthesis of NSDOPS with SadA. Structure-based protein engineering was applied to improve the α-KG turnover activity for the synthesis of NSDOPS. The G79A, G79A/F261W or G79A/F261R mutant showed a more than 6-fold increase in activity compared to that of the wild-type enzyme. The results provide a new insight into the substrate specificity toward NSDOPA and will be useful for the rational design of SadA mutants as a target of industrial biocatalysts. Copyright © 2014 Elsevier Inc. All rights reserved.

Decreasing Phosphorus Loss in Tile-Drained Landscapes Using Flue Gas Desulfurization Gypsum.

PubMed

King, K W; Williams, M R; Dick, W A; LaBarge, G A

2016-09-01

Elevated phosphorus (P) loading from agricultural nonpoint-source pollution continues to impair inland waterbodies throughout the world. The application of flue gas desulfurization (FGD) gypsum to agricultural fields has been suggested to decrease P loading because of its high calcium content and P sorbing potential. A before-after control-impact paired field experiment was used to examine the water quality effects of successive FGD gypsum applications (2.24 Mg ha; 1 ton acre each) to an Ohio field with high soil test P levels (>480 ppm Mehlich-3 P). Analysis of covariance was used to compare event discharge, dissolved reactive P (DRP), and total P (TP) concentrations and loadings in surface runoff and tile discharge between the baseline period (86 precipitation events) and Treatment Period 1 (42 precipitation events) and Treatment Period 2 (84 precipitation events). Results showed that, after the first application of FGD gypsum, event mean DRP and TP concentrations in treatment field tile water were significantly reduced by 21 and 10%, respectively, and DRP concentrations in surface runoff were significantly reduced by 14%; however, no significant reductions were noted in DRP or TP loading. After the second application, DRP and TP loads were significantly reduced in surface runoff (DRP, 41%; TP 40%), tile discharge (DRP, 35%; TP, 15%), and combined (surface + tile) discharge (DRP, 36%; TP, 38%). These findings indicate that surface application of FGD gypsum can be used as a tool to address elevated P concentrations and loadings in drainage waters. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

A novel biocatalytic approach to acetylation of 1-β-D-arabinofuranosylcytosine by Aspergillus oryzae whole cell in organic solvents.

PubMed

Li, Xiao-Feng; Zhu, Zhen; Zhao, Guang-Lei; Yu, Yi-Gang; Lai, Fu-Rao; Wu, Hui

2012-01-01

Biocatalytic acylation of 1-β-D-arabinofuranosylcytosine (ara-C) was developed using whole cell of Aspergillus oryzae as a novel catalyst. (13)C nuclear magnetic resonance (NMR) analysis indicated that the whole-cell biocatalyst had more specific activity toward the 3'-hydroxyl group than 5'-hydroxyl group among the available hydroxyl groups in sugar moiety of ara-C. Except for glucose and maltose, 11 carbon sources supplemented to basal media, including Spans, Tweens, olive oil and oleic acid, exhibited notable enhancement effects on both the cell growth and the acylation reactions. It was suggested that the carbon sources containing controlled-release oleic acid were the important substrates for the production of fungal cell-bound lipase with specific activity, partially due to a gradual induction effect of their released oleic acid on the cell-bound lipase production. Despite the low initial reaction rate and substrate conversion, the addition of 2.0 g/l Span 80 resulted in a higher 3'-regioselectivity of the cells than 81%. By using Tween 85 at its optimum concentration of 5.0 g/l, however, the highest initial rates (3.2 mmol/l h) and substrate conversion (76%) of the whole-cell catalyzed acylation of ara-C can be achieved. It was also found that the 3'-regioselectivity of the cells showed observable increase by extending the culture time. And the activity of cell-bound lipase drastically increased in the early stage of cell growth and then declined in the late culture stage, whatever the culture media used. Our results thus indicated that A. oryzae whole cell was a promising green tool for biosynthesis of nucleoside esters with potential bioactivities.

Impact of leaching conditions on constituents release from Flue Gas Desulfurization Gypsum (FGDG) and FGDG-soil mixture.

PubMed

Koralegedara, N H; Al-Abed, S R; Arambewela, M K J; Dionysiou, D D

2017-02-15

The interest in using Flue Gas Desulfurization Gypsum (FGDG) for land applications has increased recently. This study evaluates the leaching characteristics of trace elements in "modern" FGDG (produced after fly ash removal) and FGDG-mixed soil (SF) under different environmental conditions using recently approved EPA leaching methods (1313-1316). These methods employ various pH and liquid-solid (LS) ratios under batch leaching, column percolation and diffusion controlled release scenarios. Toxicity Characteristic Leaching Protocol (TCLP) and Synthetic Precipitation Leaching Protocol (SPLP) were used for comparison. The data obtained from new EPA methods provide broad insight into constituent release from FGDG and SF when compared to TCLP and SPLP. The release of toxic elements such as Hg, As, Pb, Co, Cd and Cr from SF was negligible. High release of B from FGDG was observed under all tested conditions; however, its release from SF was low. Both FGDG and SF released Se under all pH conditions (2-13) and LS ratios (1-10) in low concentrations (0.02-0.2mg/L). The data from this study could be used to investigate potential use of "modern" FGDG for new beneficial land applications. Published by Elsevier B.V.

Reusing effluent of flue gas desulfurization wastewater treatment process as an economical calcium source for phosphorus removal.

PubMed

Dou, Weixiao; Zhou, Zhen; Ye, Jiongjiong; Huang, Rongwei; Jiang, Lu-Man; Chen, Guofeng; Fei, Xiaoyun

2017-09-01

Flue gas desulfurization (FGD) wastewater treatment by conventional neutralization, chemical precipitation and coagulation process removes most suspended solids and heavy metals, and provides an effluent rich in calcium, alkalinity and chloride, which obstructs its reclamation and reuse but is in favor of phosphorus (P) precipitation. The goals of this study were to investigate feasibility of reusing FGD effluent as a calcium source for P removal from P-rich wastewater. Results revealed that increasing the volumetric ratio between FGD effluent and P-rich wastewater achieved higher pH value and Ca/P ratio, and thus enhanced P removal efficiency to 94.3% at the ratio of 40%. X-ray diffraction and scanning electron microscope analysis of harvested precipitates showed that increasing pH from 8 to 10 induced the conversion of hydroxyapatite to tri-calcium phosphate, and then to whitlockite. This study demonstrated that for reusing FGD effluent for P removal was highly feasible, both technically and economically. This process not only saves the cost of precipitants for P removal, but also provides an economical alternative for current zero liquid discharge technology for FGD wastewater, which requires high energy consumption and capital costs.

Photo and biocatalytic activities along with UV protection properties on polyester fabric through green in-situ synthesis of cauliflower-like CuO nanoparticles.

PubMed

Rezaie, Ali Bashiri; Montazer, Majid; Rad, Mahnaz Mahmoudi

2017-11-01

In this paper, a facile environmentally friendly method is introduced for in-situ synthesis and fabrication of cauliflower-like CuO nanoparticles on the polyester fabric to produce photo and biocatalytic activities with UV protection properties on polyester fabric. The ash of burnt leaves and stems of Seidlitzia rosmarinus plant called Keliab was used as a natural and nontoxic alkaline source for simultaneous synthesis of CuO nanoparticles and surface modification of polyester without using any other compounds. The images of field-emission scanning electron microscopy, patterns of energy-dispersive spectroscopy, UV-visible spectrum and X-ray diffraction confirmed successful synthesis and loading of CuO nanoparticles on the polyester fabric. The treated fabrics showed very good antibacterial activities toward two pathogen bacteria including Staphylococcus aureus as a Gram-positive and Escherichia coli as a Gram-negative bacteria with no adverse effects on human dermal fibroblasts based on MTT test. The treated fabrics confirmed significant photocatalytic activity for degradation of methylene blue under sunlight, self-cleaning properties under UV light and also UV protection properties. Further a colorant effect along with an improvement in the wettability and mechanical properties of the treated fabrics were indicated. Overall, this method can be applied as a clean route for producing photo and bio active textiles protecting against UV irradiation. Copyright © 2017 Elsevier B.V. All rights reserved.

The chemical and oxidation characteristics of semi-dry flue gas desulfurization ash from a steel factory.

PubMed

Liu, Ren-ping; Guo, Bin; Ren, Ailing; Bian, Jing-feng

2010-10-01

Some samples of semi-dry flue gas desulfurization (FGD) ash were taken from sinter gas of a steel factory. Scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses were employed to identify the samples in order to investigate their physical and chemical characteristics. The results show that semi-dry FGD ash from a steel factory is stable under atmospheric conditions. It has irregular shape, a smooth surface and loose construction. The size of FGD ash particles is around 0.5-25 µm, the average size is about 5 µm and the median diameter is 4.18 µm. Semi-dry FGD ash from a steel factory consists of CaSO₃, CaSO₄, CaCO₃, some amorphous vitreous material and unburned carbon. An experimental method was found to study the oxidation characteristics of ash. A prediction model of the oxidation efficiency was obtained based on response surface methodology. The results show that not only the temperature, but also gas:solid ratio, play an important role in influencing the oxidation efficiency. The interactions of the gas:solid ratio with temperature play an essential role. An improved response surface model was obtained which can be helpful to describe the degree of oxidation efficiency of semi-dry FGD ash.

Influence Of Coal Combustion Flue Gas Desulfurization Waste On Element Uptake By Maize (Zea Mays L.)

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

ANNA, KNOX

2005-01-10

A greenhouse study was conducted to determine the effect of coal combustion flue gas desulfurization (FGD) waste from a coal combustion electric power facility on element uptake by maize (Zea mays L.). Unweathered FGD was applied to an Orangeburg Series (Typic Paleudult) soil with an initial soil pH salt of 4.90. The FGD was added at 0, 1, 2, 4, 6, 8, and 10 per cent by weight. The test plant, maize, was harvested after 6 weeks of growth. Within 56 days of the FGD application, all rates of FGD significantly increased pH in the soil and the soil leachatemore » above 6.0. The elemental concentration of the maize tissues indicated a characteristic elevation of B, Se, Mo, and As. However, no visual symptoms of toxicity of B or other elements in plants were observed. Increasing level of FGD caused a steady decline in dry weight, with the highest treatment producing plants which had approximately half the biomass of the control plants. Due to elevated concentrations of B and other elements and due to adverse yield effects measured on plants, unweathered FGD would not be a suitable amendment for 6-week old maize on this soil.« less

Desulfurization of Thiophene on Au/TiC(001): Au−C Interactions and Charge Polarization

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

Rodriguez, J.; Liu, P; Takahashi, Y

2009-01-01

Photoemission and first-principles DF calculations were used to study the interaction of thiophene with TiC(001) and Au/TiC(001) surfaces. The adsorption strength of thiophene on TiC(001) is weak, and the molecule desorbs at temperatures below 200 K. The molecule binds to Ti centers of TiC(001) through its sulfur atom with negligible structural perturbations. In spite of the very poor desulfurization performance of TiC(001) or Au(111), a Au/TiC(001) system displays a hydrodesulfurization activity higher than that of conventional Ni/MoS{sub x} catalysts. The Au?TiC(001) interactions induce a polarization of electron density around Au which substantially increases the chemical reactivity of this metal. Aumore » nanoparticles drastically increase the hydrodesulfurization activity of TiC(001) by enhancing the bonding energy of thiophene and by helping in the dissociation of H{sub 2} to produce the hydrogen necessary for the hydrogenolysis of C-S bonds and the removal of sulfur. H{sub 2} spontaneously dissociates on small two-dimensional clusters of gold in contact with TiC(001). On these systems, the adsorption energy of thiophene is 0.45-0.65 eV larger than that on TiC(001) or Au(111). Thiophene binds in a ?5 configuration with a large elongation ({approx}0.2 {angstrom}) of the C-S bonds.« less

Direct synthesis of Ti-containing SBA-16-type mesoporous material by the evaporation-induced self-assembly method and its catalytic performance for oxidative desulfurization.

PubMed

Shah, Asma Tufail; Li, Baoshan; Abdalla, Zaki Eldin Ali

2009-08-15

A novel Ti-containing SBA-16-type mesoporous material (with various Ti loadings of 5, 10, and 15 wt%) was synthesized by an evaporation-induced self-assembly method using F127 copolymer as template. The materials were characterized by XRD, FTIR, TG-DTA, N(2) adsorption, SEM, HRTEM, and XPS. The characterization results show that the material possesses high thermal stability, thick pore walls (10.43-10.68 nm), and high surface area (642.26-691.5 m(2)/g) with a mesoporous worm-like structure, and titanium was successfully incorporated into the silica matrix with a tetrahedral environment. The material showed high activity in the oxidative desulfurization of DBT and its activity was not reduced even after three times recycling; further reuse resulted in a gradual decrease in its activity.

Immobilisation and characterisation of biocatalytic co-factor recycling enzymes, glucose dehydrogenase and NADH oxidase, on aldehyde functional ReSyn™ polymer microspheres.

PubMed

Twala, Busisiwe V; Sewell, B Trevor; Jordaan, Justin

2012-05-10

The use of enzymes in industrial applications is limited by their instability, cost and difficulty in their recovery and re-use. Immobilisation is a technique which has been shown to alleviate these limitations in biocatalysis. Here we describe the immobilisation of two biocatalytically relevant co-factor recycling enzymes, glucose dehydrogenase (GDH) and NADH oxidase (NOD) on aldehyde functional ReSyn™ polymer microspheres with varying functional group densities. The successful immobilisation of the enzymes on this new high capacity microsphere technology resulted in the maintenance of activity of ∼40% for GDH and a maximum of 15.4% for NOD. The microsphere variant with highest functional group density of ∼3500 μmol g⁻¹ displayed the highest specific activity for the immobilisation of both enzymes at 33.22 U mg⁻¹ and 6.75 U mg⁻¹ for GDH and NOD with respective loading capacities of 51% (0.51 mg mg⁻¹) and 129% (1.29 mg mg⁻¹). The immobilised GDH further displayed improved activity in the acidic pH range. Both enzymes displayed improved pH and thermal stability with the most pronounced thermal stability for GDH displayed on ReSyn™ A during temperature incubation at 65 °C with a 13.59 fold increase, and NOD with a 2.25-fold improvement at 45 °C on the same microsphere variant. An important finding is the suitability of the microspheres for stabilisation of the multimeric protein GDH. Copyright © 2012 Elsevier Inc. All rights reserved.

Alcohol Selectivity in a Synthetic Thermophilic n-Butanol Pathway Is Driven by Biocatalytic and Thermostability Characteristics of Constituent Enzymes

PubMed Central

Loder, Andrew J.; Zeldes, Benjamin M.; Garrison, G. Dale; Lipscomb, Gina L.; Adams, Michael W. W.

2015-01-01

n-Butanol is generated as a natural product of metabolism by several microorganisms, but almost all grow at mesophilic temperatures. A synthetic pathway for n-butanol production from acetyl coenzyme A (acetyl-CoA) that functioned at 70°C was assembled in vitro from enzymes recruited from thermophilic bacteria to inform efforts for engineering butanol production into thermophilic hosts. Recombinant versions of eight thermophilic enzymes (β-ketothiolase [Thl], 3-hydroxybutyryl-CoA dehydrogenase [Hbd], and 3-hydroxybutyryl-CoA dehydratase [Crt] from Caldanaerobacter subterraneus subsp. tengcongensis; trans-2-enoyl-CoA reductase [Ter] from Spirochaeta thermophila; bifunctional acetaldehyde dehydrogenase/alcohol dehydrogenase [AdhE] from Clostridium thermocellum; and AdhE, aldehyde dehydrogenase [Bad], and butanol dehydrogenase [Bdh] from Thermoanaerobacter sp. strain X514) were utilized to examine three possible pathways for n-butanol. These pathways differed in the two steps required to convert butyryl-CoA to n-butanol: Thl-Hbd-Crt-Ter-AdhE (C. thermocellum), Thl-Hbd-Crt-Ter-AdhE (Thermoanaerobacter X514), and Thl-Hbd-Crt-Ter-Bad-Bdh. n-Butanol was produced at 70°C, but with different amounts of ethanol as a coproduct, because of the broad substrate specificities of AdhE, Bad, and Bdh. A reaction kinetics model, validated via comparison to in vitro experiments, was used to determine relative enzyme ratios needed to maximize n-butanol production. By using large relative amounts of Thl and Hbd and small amounts of Bad and Bdh, >70% conversion to n-butanol was observed in vitro, but with a 60% decrease in the predicted pathway flux. With more-selective hypothetical versions of Bad and Bdh, >70% conversion to n-butanol is predicted, with a 19% increase in pathway flux. Thus, more-selective thermophilic versions of Bad, Bdh, and AdhE are needed to fully exploit biocatalytic n-butanol production at elevated temperatures. PMID:26253677

Methane production from a field-scale biofilter designed for desulfurization of biogas stream.

PubMed

Pirolli, Mateus; da Silva, Márcio Luís Busi; Mezzari, Melissa Paola; Michelon, William; Prandini, Jean Michel; Moreira Soares, Hugo

2016-07-15

The development of a simple and low maintenance field-scale biotrickling filter (BTF) for desulfurization of swine wastewater-derived biogas stream that was also capable of increasing biomethane concentrations was investigated. BTF was continuously fed with wastewater effluent from an air sparged nitrification-denitrification bioreactor installed downgradient from an UASB-type digester. BTF maximum removal efficiency (RE) of 99.8% was achieved with a maximum elimination capacity (EC) of 1,509 g H2S m(-3) h(-1). Average EC obtained with inlet biogas flow rates of 0.024, 0.036 and 0.048 m(3) h(-1) was 718, 1,013 and 438 g H2S m(-3) h(-1), respectively. SO4(-2) and S(0) were the major metabolites produced from biological conversion of H2S. Additionally to the satisfactory biodesulfurization capacity, an average increase in methane concentration of ≅ 3.8 ± 1.68 g m(-3) was measured in the filtered gas stream throughout 200 days of BTF operation. RT-PCR analyses of archaea communities in the biofilm confirmed dominance of hydrogenotrophic methanogens thus corroborating with the observed strong correlation between CO2 removal and CH4 production. Among the three major archaea orders investigated (i.e., Methanosarcinales, Methanobacteriales, and Methanomicrobiales), Methanobacteriales were encountered at highest concentrations (1.9 × 10(11) gene copies mL(-1)). The proposed BTF was robust efficiently removing H2S from biogas stream while concomitantly enhancing the concentration of valuable methane as source of renewable fuel. Copyright © 2016 Elsevier Ltd. All rights reserved.

Oxidative degradation of organic acids conjugated with sulfite oxidation in flue gas desulfurization

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

Lee, Y.I.

Organic acid degradation conjugated with sulfite oxidation has been studied under flue gas desulfurization (EGD) conditions. The oxidative degradation constant, k/sub 12/, is defined as the ratio of organic acid degradation rate and sulfite oxidation rate after being normalized by the concentrations of organic acid and dissolved S(IV). K/sub 12/, not significantly affected by pH or dissolved oxygen, is around 10/sup -3/ in the absence of manganese or iron. However, k/sub 12/ is increased by certain transition metals such as Co, Ni, and Fe and is decreased by Mn and halides. Lower dissolved S(IV) magnified these effects. No k/sub 12/more » greater than 4 x 10/sup -3/ or smaller than 0.1 x 10/sup -3/ has been observed. A free radical mechanism was proposed to describe the kinetics: (1) sulfate free radical is the major radical responsible to the degradation of organic acid; (2) ferrous generates sulfate radical by reacting with monoxypersulfate to enhance k/sub 12/; (3) manganous consumes sulfate radical to decrease k/sub 12/; (4) dissolved S(IV) competes with ferrous for monoxypersulfate and with manganous for sulfate radical to demonstrate the effects of dissolved S(IV) on k/sub 12/. Hydroxy and sulfonated carboxylic acids degrade approximately three times slower than saturated dicarboxylic acids; while maleic acid, an unsaturated dicarboxylic acid, degraded an order of magnitude faster. A wide spectrum of degradation products of adipic acid were found, including carbon dioxide - the major product, glutaric semialdehyde - the major retained product with low manganese, glutaric acid and valeric acids - the major retained product with high manganese, lower molecular weight mono- and dicarboxylic acids, other carbonyl compounds, and hydrocarbons.« less

Experimental study of the combined calcination and hydrodesulfurization of high-sulfur green petroleum coke

NASA Astrophysics Data System (ADS)

Kilic, Saliha Meltem

The primary production of aluminum is done by means of the Hall-Heroult process where large amounts of carbon anodes are required and consumed. The quality of carbon anodes used in electrolysis is one of the most important parameters affecting the production of primary aluminum. The anode quality widely depends on the raw materials, one of which is the petroleum coke. Green petroleum coke is produced from the heavy residual fractions of petroleum. Petroleum cokes produced from sour crude oil sources contain high quantity of sulfur. A certain level of sulfur is needed to reduce the anode reactivities; however, the demand for anode-grade coke with acceptable sulfur content is increasing faster than the available supply. High sulfur levels in carbon anodes would have an adverse effect on environment; hence, the desulfurization of high sulfur green petroleum cokes is necessary. There are different ways of desulfurizing green petroleum cokes: solvent extraction, thermal desulfurization, and hydrodesulfurization. Coke produced by solvent extraction is prone to contamination. The thermal approach requires greater energy consumption and causes an increase in coke porosity. The global objective of this master project is to find an alternative solution for desulfurization that will produce quality calcined coke with minimum impact on environment. Hydrodesulfurization seems to be a viable option and was investigated in this study. Water was used for the hydrodesulfurization of commercially available high sulfur green petroleum coke. Different experimental systems were tried during the hydrodesulfurization experiments. A systematic approach was used to investigate the influence of hydrodesulfurization parameters including water injection temperature, duration, and water flow rate as well as coke particle size on the hydrodesulfurization of green petroleum coke. In addition to hydrodesulfurization, a number of thermal desulfurization experiments were carried out with the same

Remediation of saline-sodic soil with flue gas desulfurization gypsum in a reclaimed tidal flat of southeast China.

PubMed

Mao, Yumei; Li, Xiaping; Dick, Warren A; Chen, Liming

2016-07-01

Salinization and sodicity are obstacles for vegetation reconstruction of coastal tidal flat soils. A study was conducted with flue gas desulfurization (FGD)-gypsum applied at rates of 0, 15, 30, 45 and 60Mg/ha to remediate tidal flat soils of the Yangtze River estuary. Exchangeable sodium percentage (ESP), exchangeable sodium (ExNa), pH, soluble salt concentration, and composition of soluble salts were measured in 10cm increments from the surface to 30cm depth after 6 and 18months. The results indicated that the effect of FGD-gypsum is greatest in the 0-10cm mixing soil layer and 60Mg/ha was the optimal rate that can reduce the ESP to below 6% and decrease soil pH to neutral (7.0). The improvement effect was reached after 6months, and remained after 18months. The composition of soluble salts was transformed from sodic salt ions mainly containing Na(+), HCO3(-)+CO3(2-) and Cl(-) to neutral salt ions mainly containing Ca(2+) and SO4(2-). Non-halophyte plants were survived at 90%. The study demonstrates that the use of FGD-gypsum for remediating tidal flat soils is promising. Copyright © 2016. Published by Elsevier B.V.

The effects of flue gas desulfurization (FGD) system additives on solid by-products. Final report

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

Huyck, K.A.; Tatum, G.S.; DeKraker, D.P.

This study was designed to examine characteristics of by-products from flue gas desulfurization (FGD) systems that use performance-enhancing additives. The by-products were evaluated for handling, disposal, properties, and utilization potential. This study was designed to identify potential operation-limiting consequences (fatal flaws) caused by using FGD system additives. It was not intended to be an all-encompassing study of the possible process, environmental, and utilization circumstances at each plant. Seven utilities conducting additive testing agreed to provide samples for this study both before and during their testing. Solid samples were collected from FGD systems using the following additives: di-basic acid (DBA), whichmore » is a mixture of succinic, glutaric, and adipic acids; formate; sulfur; ethylene diamine tetraacetic acid (EDTA); and chloride. Changes in handling properties that may alter process operations were observed at sites where DBS was used. Changes in leaching behavior, permeability and unconfined compressive strength (properties that affect by-product disposal properties) showed no clear trend for additive or system type. The intent of this study is to provide an overall assessment of potential system-limiting effects of FGD additive use. There were no overriding problems relating to disposal with the use of additives. However, properties of solids produced with and without additives should be tested at each site prior to use of an FGD system additive. This is necessary because of the variability in state disposal and permitting requirements and the influence of specific operating conditions on by-product properties.« less

Influence of Flue Gas Desulfurization Gypsum Amendments on Heavy Metal Distribution in Reclaimed Sodic Soils.

PubMed

Chen, Qun; Wang, Shujuan; Li, Yan; Zhang, Ning; Zhao, Bo; Zhuo, Yuqun; Chen, Changhe

2015-06-01

Although flue gas desulfurization (FGD) gypsum has become an effective soil amendment for sodic soil reclamation, it carries extra heavy metal contamination into the soil environment. The fate of heavy metals introduced by FGD gypsum in sodic or saline-alkali soils is still unclear. This work aims to investigate the effects of FGD gypsum addition on the heavy metal distributions in a sodic soil. Original soil samples were collected from typical sodic land in north China. Soil column leaching tests were conducted to investigate the influence of FGD gypsum addition on the soil properties, especially on distribution profiles of the heavy metals (Pb, Cd, Cr, As, and Hg) in the soil layers. Results showed that pH, electrical conductivity, and exchangeable sodium percentage in amended soils were significantly reduced from 10.2 to 8.46, 1.8 to 0.2 dS/m, and 18.14% to 1.28%, respectively. As and Hg concentrations in the soils were found to be positively correlated with FGD gypsum added. The amount of Hg in the leachate was positively correlated with FGD gypsum application ratio, whereas a negative correlation was observed between the Pb concentration in the leachate and the FGD gypsum ratio. Results revealed that heavy metal concentrations in soils complied well with Environmental Quality Standard for Soils in China (GB15618-1995). This work helps to understand the fate of FGD gypsum-introduced heavy metals in sodic soils and provides a baseline for further environmental risk assessment associated with applying FGD gypsum for sodic soil remediation.

Influence of Flue Gas Desulfurization Gypsum Amendments on Heavy Metal Distribution in Reclaimed Sodic Soils

PubMed Central

Chen, Qun; Wang, Shujuan; Li, Yan; Zhang, Ning; Zhao, Bo; Zhuo, Yuqun; Chen, Changhe

2015-01-01

Abstract Although flue gas desulfurization (FGD) gypsum has become an effective soil amendment for sodic soil reclamation, it carries extra heavy metal contamination into the soil environment. The fate of heavy metals introduced by FGD gypsum in sodic or saline–alkali soils is still unclear. This work aims to investigate the effects of FGD gypsum addition on the heavy metal distributions in a sodic soil. Original soil samples were collected from typical sodic land in north China. Soil column leaching tests were conducted to investigate the influence of FGD gypsum addition on the soil properties, especially on distribution profiles of the heavy metals (Pb, Cd, Cr, As, and Hg) in the soil layers. Results showed that pH, electrical conductivity, and exchangeable sodium percentage in amended soils were significantly reduced from 10.2 to 8.46, 1.8 to 0.2 dS/m, and 18.14% to 1.28%, respectively. As and Hg concentrations in the soils were found to be positively correlated with FGD gypsum added. The amount of Hg in the leachate was positively correlated with FGD gypsum application ratio, whereas a negative correlation was observed between the Pb concentration in the leachate and the FGD gypsum ratio. Results revealed that heavy metal concentrations in soils complied well with Environmental Quality Standard for Soils in China (GB15618-1995). This work helps to understand the fate of FGD gypsum-introduced heavy metals in sodic soils and provides a baseline for further environmental risk assessment associated with applying FGD gypsum for sodic soil remediation. PMID:26064038

Alcohol Selectivity in a Synthetic Thermophilic n-Butanol Pathway Is Driven by Biocatalytic and Thermostability Characteristics of Constituent Enzymes.

PubMed

Loder, Andrew J; Zeldes, Benjamin M; Garrison, G Dale; Lipscomb, Gina L; Adams, Michael W W; Kelly, Robert M

2015-10-01

n-Butanol is generated as a natural product of metabolism by several microorganisms, but almost all grow at mesophilic temperatures. A synthetic pathway for n-butanol production from acetyl coenzyme A (acetyl-CoA) that functioned at 70°C was assembled in vitro from enzymes recruited from thermophilic bacteria to inform efforts for engineering butanol production into thermophilic hosts. Recombinant versions of eight thermophilic enzymes (β-ketothiolase [Thl], 3-hydroxybutyryl-CoA dehydrogenase [Hbd], and 3-hydroxybutyryl-CoA dehydratase [Crt] from Caldanaerobacter subterraneus subsp. tengcongensis; trans-2-enoyl-CoA reductase [Ter] from Spirochaeta thermophila; bifunctional acetaldehyde dehydrogenase/alcohol dehydrogenase [AdhE] from Clostridium thermocellum; and AdhE, aldehyde dehydrogenase [Bad], and butanol dehydrogenase [Bdh] from Thermoanaerobacter sp. strain X514) were utilized to examine three possible pathways for n-butanol. These pathways differed in the two steps required to convert butyryl-CoA to n-butanol: Thl-Hbd-Crt-Ter-AdhE (C. thermocellum), Thl-Hbd-Crt-Ter-AdhE (Thermoanaerobacter X514), and Thl-Hbd-Crt-Ter-Bad-Bdh. n-Butanol was produced at 70°C, but with different amounts of ethanol as a coproduct, because of the broad substrate specificities of AdhE, Bad, and Bdh. A reaction kinetics model, validated via comparison to in vitro experiments, was used to determine relative enzyme ratios needed to maximize n-butanol production. By using large relative amounts of Thl and Hbd and small amounts of Bad and Bdh, >70% conversion to n-butanol was observed in vitro, but with a 60% decrease in the predicted pathway flux. With more-selective hypothetical versions of Bad and Bdh, >70% conversion to n-butanol is predicted, with a 19% increase in pathway flux. Thus, more-selective thermophilic versions of Bad, Bdh, and AdhE are needed to fully exploit biocatalytic n-butanol production at elevated temperatures. Copyright © 2015, American Society for

Chiyoda Thoroughbred CT-121 clean coal project at Georgia Power`s Plant Yates

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

Burford, D.P.

1997-12-31

The Chiyoda Thoroughbred CT-121 flue gas desulfurization (FGD) process at Georgia Power`s Plant Yates completed a two year demonstration of its capabilities in late 1994 under both high- and low-particulate loading conditions. This $43 million demonstration was co-funded by Southern Company, the Electric Power Research Institute and the DOE under the auspices of the US Department of Energy`s Round II Innovative Clean Coal Technology (ICCT) program. The focus of the Yates Project was to demonstrate several cost-saving modifications to Chiyoda`s already efficient CT-121 process. These modifications included: the extensive use of fiberglass reinforced plastics (FRP) in the construction of themore » scrubber vessel and other associated vessels, the elimination of flue gas reheat through the use of an FRP wet chimney, and reliable operation without a spare absorber module. This paper focuses on the testing results from the last trimester of the second phase of testing (high-ash loading). Specifically, operation under elevated ash loading conditions, the effects of low- and high-sulfur coal, air toxics verification testing results and unexpected improvements in byproduct gypsum quality are discussed.« less

Clean-Coal Technology By-Products Used in a Highway Embankment Stabilization Demonstration Project

DTIC Science & Technology

1994-01-01

the conventional coal combustion process (Tismach, 1993). -- 0.. 3 The flue gas desulfurization (FGD) material used in this study was produced at...suitable material for stabilizing this slide. 000 Figure 1.3: SR 83 Cross-Section. i0l 11 1.4 Scope and Limitations The disposal of flue gas ...Sciences, Washington, DC. 19. Taha, R., "Environmental and Engineering Properties of Flue Gas Desulfuimzation Gypsum," Preprint. 72nd Annual Meetin

On understanding proton transfer to the biocatalytic [Fe-Fe](H) sub-cluster in [Fe-Fe]H(2)ases: QM/MM MD simulations.

PubMed

Hong, G; Cornish, A J; Hegg, E L; Pachter, R

2011-05-01

Proton transfer to the [Fe-Fe](H) sub-cluster in the Desulfovibrio desulfuricans (DdH) and Clostridium pasteurianum (CpI) [Fe-Fe] hydrogenases was investigated by a combination of first principles and empirical molecular dynamics simulations. Pathways that can be inferred from the X-ray crystal structures of DdH and CpI, i.e., (Glu159→Ser198→Glu156→water460→Cys178→DTMA([Fe-Fe](H)) and (Glu282→Ser319→Glu279→water612→Cys299), respectively, were considered. Proton transfer from Cys178 to DTMA in the [Fe-Fe](H) sub-cluster in DdH was readily observed in our results, specifically when [Fe-Fe](H) was in the reduced state ([Fe(I)-Fe(I)]) or in the mixed valence state for the protonated distal iron Fe(d) ([Fe(I)-Fe(II)-H(-)](H)). A concerted mechanism is proposed, where proton transfer in DdH from Glu159 to Glu156 via Ser198 and Glu156 to Cys178 via water460 readily occurred, as well as from Glu282 to Glu279 via Ser319 and Glu279 to Cys299 via water612 in CpI. The theoretical prediction of the proton transfer characteristics is consistent with the assumed biocatalytic mechanism of the [Fe-Fe] hydrogenases in which the proton binds at Fe(d), providing confirmation that has not been explored so far. The computational results were qualitatively validated by the agreement with experimental hydrogen production activity data for mutated CpI enzymes, relative to the wild-type protein. Finally, the insight provided by the simulations, combined, in part, with experimental validation, are important for establishing an approach in future exploration of proton transfer to the active site in this class of enzymes, and possibly also for biomimetic analogs. Published by Elsevier B.V.

40 CFR 52.1677 - Compliance schedules.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 1, 1973, of his intent to utilize either low-sulfur fuel or stack gas desulfurization to meet the...) of this section who elects low-sulfur fuel shall be subject to the following compliance schedule: (i) November 1, 1973—Submit to the Administrator a projection of the amount of fuel, by types, that will be...

Effect of gas-liquid flow pattern and microbial diversity analysis of a pilot-scale biotrickling filter for anoxic biogas desulfurization.

PubMed

Almenglo, Fernando; Bezerra, Tercia; Lafuente, Javier; Gabriel, David; Ramírez, Martín; Cantero, Domingo

2016-08-01

Hydrogen sulfide removal from biogas was studied under anoxic conditions in a pilot-scale biotrickling filter operated under counter- and co-current gas-liquid flow patterns. The best performance was found under counter-current conditions (maximum elimination capacity of 140 gS m(-3) h(-1)). Nevertheless, switching conditions between co- and counter-current flow lead to a favorable redistribution of biomass and elemental sulfur along the bed height. Moreover, elemental sulfur was oxidized to sulfate when the feeding biogas was disconnected and the supply of nitrate (electron acceptor) was maintained. Removal of elemental sulfur was important to prevent clogging in the packed bed and, thereby, to increase the lifespan of the packed bed between maintenance episodes. The larger elemental sulfur removal rate during shutdowns was 59.1 gS m(-3) h(-1). Tag-encoded FLX amplicon pyrosequencing was used to study the diversity of bacteria under co-current flow pattern with liquid recirculation and counter-current mode with a single-pass flow of the liquid phase. The main desulfurizing bacteria were Sedimenticola while significant role of heterotrophic, opportunistic species was envisaged. Remarkable differences between communities were found when a single-pass flow of industrial water was fed to the biotrickling filter. Copyright © 2016 Elsevier Ltd. All rights reserved.

Testing CO2 Sequestration in an Alkaline Soil Treated with Flue Gas Desulfurization Gypsum (FGDG)

NASA Astrophysics Data System (ADS)

Han, Y.; Tokunaga, T. K.

2012-12-01

Identifying effective and economical methods for increasing carbon storage in soils is of interest for reducing soil CO2 fluxes to the atmosphere in order to partially offset anthropogenic CO2 contributions to climate change This study investigates an alternative strategy for increasing carbon retention in soils by accelerating calcite (CaCO3) precipitation and promoting soil organic carbon (SOC) complexation on mineral surfaces. The addition of calcium ion to soils with pH > 8, often found in arid and semi-arid regions, may accelerate the slow process of calcite precipitation. Increased ionic strength from addition of a soluble Ca source also suppresses microbial activity which oxidizes SOC to gaseous CO2. Through obtaining C mass balances in soil profiles, this study is quantifying the efficiency of gypsum amendments for mitigating C losses to the atmosphere. The objective of this study is to identify conditions in which inorganic and organic C sequestration is practical in semi-arid and arid soils by gypsum treatment. As an inexpensive calcium source, we proposed to use flue gas desulfurization gypsum (FGDG), a byproduct of fossil fuel burning electric power plants. To test the hypothesis, laboratory column experiments have been conducted in calcite-buffered soil with addition of gypsum and FGDG. The results of several months of column monitoring are demonstrating that gypsum-treated soil have lowered amounts of soil organic carbon loss and increased inorganic carbon (calcite) production. The excess generation of FGDG relative to industrial and agricultural needs, FGDG, is currently regarded as waste. Thus application of FGDG application in some soils may be an effective and economical means for fixing CO2 in soil organic and inorganic carbon forms.Soil carbon cycle, with proposed increased C retention by calcite precipitation and by SOC binding onto soil mineral surfaces, with both processes driven by calcium released from gypsum dissolution.

Formation of (FexMn(2-x))O3 solid solution and high sulfur capacity properties of Mn-based/M41 sorbents for hot coal gas desulfurization.

PubMed

Zhang, Y; Liu, B S; Zhang, F M; Zhang, Z F

2013-03-15

Several MCM-41 materials were synthesized at different conditions by hydrothermal procedure using cheap and easily available industrial water glass as silica source. Fe doped manganese-based oxide/MCM-41 sorbents were prepared by a sol-gel method. The effects of loadings of metal oxide, Fe/Mn molar ratios over MCM-41 and reaction temperature on the performance of sorbent for hot coal gas desulfurization were investigated. Various techniques such as BET, XRD, XPS, LRS and HRTEM were used to characterize the sorbents. The result indicated Fe(3+) ions could occupy a position of Mn(3+) in cubic lattice of Mn2O3 and the (FexMn2-x)O3 solid solution is mainly active phase of sorbent. Moreover, the result of nine successive sulfurization-regeneration cycles of sorbent showed high sulfur adsorption capacity and endurable stability of FeMn4Ox/MCM-41 for H2S removal. Copyright © 2013 Elsevier B.V. All rights reserved.

Continuous-flow ultrasound assisted oxidative desulfurization (UAOD) process: An efficient diesel treatment by injection of the aqueous phase.

PubMed

Rahimi, Masoud; Shahhosseini, Shahrokh; Movahedirad, Salman

2017-11-01

A new continuous-flow ultrasound assisted oxidative desulfurization (UAOD) process was developed in order to decrease energy and aqueous phase consumption. In this process the aqueous phase is injected below the horn tip leading to enhanced mixing of the phases. Diesel fuel as the oil phase with sulfur content of 1550ppmw and an appropriate mixture of hydrogen peroxide and formic acid as the aqueous phase were used. At the first step, the optimized condition for the sulfur removal has been obtained in the batch mode operation. Hence, the effect of more important oxidation parameters; oxidant-to-sulfur molar ratio, acid-to-sulfur molar ratio and sonication time were investigated. Then the optimized conditions were obtained using Response Surface Methodology (RSM) technique. Afterwards, some experiments corresponding to the best batch condition and also with objective of minimizing the residence time and aqueous phase to fuel volume ratio have been conducted in a newly designed double-compartment reactor with injection of the aqueous phase to evaluate the process in a continuous flow operation. In addition, the effect of nozzle diameter has been examined. Significant improvement on the sulfur removal was observed specially in lower sonication time in the case of dispersion method in comparison with the conventional contact between two phases. Ultimately, the flow pattern induced by ultrasonic device, and also injection of the aqueous phase were analyzed quantitatively and qualitatively by capturing the sequential images. Copyright © 2017 Elsevier B.V. All rights reserved.

Land application uses of dry FGD by-products. [Quarterly report, January 1, 1994--March 31, 1994

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

Dick, W.A.; Beeghly, J.H.

1994-08-01

This report contains three separate monthly reports on the progress to use flue gas desulfurization by-products for the land reclamation of an abandoned mine site in Ohio. Data are included on the chemical composition of the residues, the cost of the project, as well as scheduling difficulties and efforts to allay the fears of public officials as to the safety of the project. The use of by-products to repair a landslide on State Route 541 is briefly discussed.

Harvesting microalgae cultures with superabsorbent polymers: desulfurization of Chlamydomonas reinhardtii for hydrogen production.

PubMed

Martín del Campo, Julia S; Patiño, Rodrigo

2013-12-01

It is presented in this work a new methodology to harvest fresh water microalgae cultures by extracting the culture medium with superabsorbent polymers (SAPs). The microalgae Chlamydomonas reinhardtii were grown in the Sueoka culture medium, harvested with polyacrylic SAPs and re-suspended in the culture medium tris-acetate-potassium without sulfur (TAP-S) to generate hydrogen (H2 ) under anoxic conditions. The H2 production as an alternative fuel is relevant since this gas has high-energy recovery without involving carbon. Before microalgae harvesting, a number of range diameters (1-7 mm) for SAPs spherical particles were tested, and the initial rate (V0 ) and the maximal capacity (Qmax ) were determined for the Sueoka medium absorption. The SAP particles with the diameter range 2.0-2.5 mm performed the best and these were employed for the rest of the experiments. The Sueoka medium has a high salt content and the effect of the ionic strength was also studied for different medium concentrations (0-400%). The SAPs were reused in consecutive absorption/desorption cycles, maintaining their absorption capacity. Although the Sueoka medium reduces the SAPs absorption capacity to 40% compared with deionized water, the use of SAPs was very significant for the desulfurization process of C. reihardtii. The presence of C. reinhardtii at different concentrations does not affect the absorption capacity of the Sueoka culture medium by the SAPs. In order to reduce the time of the process, an increase of the SAPs concentration was tested, being 20 g of SAP per liter of medium, a condition to harvest the microalgae culture in 4 h. There were no evident cell ruptures during the harvesting process and the cells remained alive. Finally, the harvested biomass was re-suspended in TAP-S medium and kept under anaerobic conditions and illumination to produce H2 that was monitored by a PEM fuel cell. The use of SAPs for microalgae harvesting is a feasible non-invasive procedure to obtain

The S02 Concern in Developed Nations

ERIC Educational Resources Information Center

Environmental Science and Technology, 1976

1976-01-01

Delegates of a working group on air pollution problems of the Economic Commission for Europe discussed the status of advanced technologies for controlling man-made emissions of sulfur dioxide. Technologies discussed included: coal washing, oil desulfurization, flue gas desulfurization, scrubbing, residual oil desulfurization, fluidized bed…

Effects of Lead and Mercury on Sulfate-Reducing Bacterial Activity in a Biological Process for Flue Gas Desulfurization Wastewater Treatment

NASA Astrophysics Data System (ADS)

Zhang, Liang; Lin, Xiaojuan; Wang, Jinting; Jiang, Feng; Wei, Li; Chen, Guanghao; Hao, Xiaodi

2016-07-01

Biological sulfate-reducing bacteria (SRB) may be effective in removing toxic lead and mercury ions (Pb(II) and Hg(II)) from wet flue gas desulfurization (FGD) wastewater through anaerobic sulfite reduction. To confirm this hypothesis, a sulfite-reducing up-flow anaerobic sludge blanket reactor was set up to treat FGD wastewater at metal loading rates of 9.2 g/m3-d Pb(II) and 2.6 g/m3-d Hg(II) for 50 days. The reactor removed 72.5 ± 7% of sulfite and greater than 99.5% of both Hg(II) and Pb(II). Most of the removed lead and mercury were deposited in the sludge as HgS and PbS. The contribution of cell adsorption and organic binding to Pb(II) and Hg(II) removal was 20.0 ± 0.1% and 1.8 ± 1.0%, respectively. The different bioavailable concentration levels of lead and mercury resulted in different levels of lethal toxicity. Cell viability analysis revealed that Hg(II) was less toxic than Pb(II) to the sludge microorganisms. In the batch tests, increasing the Hg(II) feeding concentration increased sulfite reduction rates. In conclusion, a sulfite-reducing reactor can efficiently remove sulfite, Pb(II) and Hg(II) from FGD wastewater.

Fabrication of magnetically responsive HKUST-1/Fe3O4 composites by dry gel conversion for deep desulfurization and denitrogenation.

PubMed

Tan, Peng; Xie, Xiao-Yan; Liu, Xiao-Qin; Pan, Ting; Gu, Chen; Chen, Peng-Fei; Zhou, Jia-Yu; Pan, Yichang; Sun, Lin-Bing

2017-01-05

Selective adsorption by use of metal-organic frameworks (MOFs) is an effective method for purification of hydrocarbon fuels. In consideration that the adsorption processes proceed in liquid phases, separation and recycling of adsorbents should be greatly facilitated if MOFs were endowed with magnetism. In the present study, we reported for the first time a dry gel conversion (DGC) strategy to fabricate magnetically responsive MOFs as adsorbents for deep desulfurization and denitrogenation. The solvent is separated from the solid materials in the DGC strategy, and vapor is generated at elevated temperatures to induce the growth of MOFs around magnetic Fe 3 O 4 nanoparticles. This strategy can greatly simplify the complicated procedures of the well-known layer-by-layer method and avoid the blockage of pores confronted by introducing magnetic Fe 3 O 4 nanoparticles to the pores of MOFs. Our results show that the adsorbents are capable of efficiently removing aromatic sulfur and nitrogen compounds from model fuels, for example removing 0.62mmolg -1 S and 0.89mmolg -1 N of thiophene and indole, respectively. In addition, the adsorbents are facile to separate from liquid phases by use of an external field. After 6 cycles, the adsorbents still show a good adsorption capacity that is comparable to the fresh one. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of Lead and Mercury on Sulfate-Reducing Bacterial Activity in a Biological Process for Flue Gas Desulfurization Wastewater Treatment

PubMed Central

Zhang, Liang; Lin, Xiaojuan; Wang, Jinting; Jiang, Feng; Wei, Li; Chen, Guanghao; Hao, Xiaodi

2016-01-01

Biological sulfate-reducing bacteria (SRB) may be effective in removing toxic lead and mercury ions (Pb(II) and Hg(II)) from wet flue gas desulfurization (FGD) wastewater through anaerobic sulfite reduction. To confirm this hypothesis, a sulfite-reducing up-flow anaerobic sludge blanket reactor was set up to treat FGD wastewater at metal loading rates of 9.2 g/m3-d Pb(II) and 2.6 g/m3-d Hg(II) for 50 days. The reactor removed 72.5 ± 7% of sulfite and greater than 99.5% of both Hg(II) and Pb(II). Most of the removed lead and mercury were deposited in the sludge as HgS and PbS. The contribution of cell adsorption and organic binding to Pb(II) and Hg(II) removal was 20.0 ± 0.1% and 1.8 ± 1.0%, respectively. The different bioavailable concentration levels of lead and mercury resulted in different levels of lethal toxicity. Cell viability analysis revealed that Hg(II) was less toxic than Pb(II) to the sludge microorganisms. In the batch tests, increasing the Hg(II) feeding concentration increased sulfite reduction rates. In conclusion, a sulfite-reducing reactor can efficiently remove sulfite, Pb(II) and Hg(II) from FGD wastewater. PMID:27455890

A green desulfurization technique: utilization of flue gas SO2 to produce H2 via a photoelectrochemical process based on Mo-doped BiVO4

NASA Astrophysics Data System (ADS)

Han, Jin; Li, Kejian; Cheng, Hanyun; Zhang, Liwu

2017-12-01

A green photoelectrochemical (PEC) process with simultaneous SO2 removal and H2 production has attracted an increasing attention. The proposed process uses flue gas SO2 to improve H2 production. The improvement of the efficiency of this process is necessary before it can become industrial viable. Herein, we reported a Mo modified BiVO4 photocatalysts for a simultaneous SO2 removal and H2 production. And the PEC performance could be significantly improved with doping and flue gas removal. The evolution rate of H2 and removal of SO2 could be enhanced by almost 3 times after Mo doping as compared with pristine BiVO4. The enhanced H2 production and SO2 removal is attributed to the improved bulk charge carrier transportation after Mo doping, and greatly enhanced oxidation reaction kinetics on the photoanode due to the formation of SO32- after SO2 absorption by the electrolyte. Due to the utilization of SO2 to improve the production of H2, the proposed PEC process may become a profitable desulfurization technique.

A Green Desulfurization Technique: Utilization of Flue Gas SO2 to Produce H2 via a Photoelectrochemical Process Based on Mo-Doped BiVO4

PubMed Central

Han, Jin; Li, Kejian; Cheng, Hanyun; Zhang, Liwu

2017-01-01

A green photoelectrochemical (PEC) process with simultaneous SO2 removal and H2 production has attracted an increasing attention. The proposed process uses flue gas SO2 to improve H2 production. The improvement of the efficiency of this process is necessary before it can become industrial viable. Herein, we reported a Mo modified BiVO4 photocatalysts for a simultaneous SO2 removal and H2 production. And the PEC performance could be significantly improved with doping and flue gas removal. The evolution rate of H2 and removal of SO2 could be enhanced by almost three times after Mo doping as compared with pristine BiVO4. The enhanced H2 production and SO2 removal is attributed to the improved bulk charge carrier transportation after Mo doping, and greatly enhanced oxidation reaction kinetics on the photoanode due to the formation of SO32− after SO2 absorption by the electrolyte. Due to the utilization of SO2 to improve the production of H2, the proposed PEC process may become a profitable desulfurization technique. PMID:29312924

A Green Desulfurization Technique: Utilization of Flue Gas SO2 to Produce H2 via a Photoelectrochemical Process Based on Mo-Doped BiVO4.

PubMed

Han, Jin; Li, Kejian; Cheng, Hanyun; Zhang, Liwu

2017-01-01

A green photoelectrochemical (PEC) process with simultaneous SO 2 removal and H 2 production has attracted an increasing attention. The proposed process uses flue gas SO 2 to improve H 2 production. The improvement of the efficiency of this process is necessary before it can become industrial viable. Herein, we reported a Mo modified BiVO 4 photocatalysts for a simultaneous SO 2 removal and H 2 production. And the PEC performance could be significantly improved with doping and flue gas removal. The evolution rate of H 2 and removal of SO 2 could be enhanced by almost three times after Mo doping as compared with pristine BiVO 4 . The enhanced H 2 production and SO 2 removal is attributed to the improved bulk charge carrier transportation after Mo doping, and greatly enhanced oxidation reaction kinetics on the photoanode due to the formation of [Formula: see text] after SO 2 absorption by the electrolyte. Due to the utilization of SO 2 to improve the production of H 2 , the proposed PEC process may become a profitable desulfurization technique.

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

Gangwal, S.K.; Gupta, R.P.; Khare, G.P.

The objectives of this project are to determine the long-term chemical reactivity and mechanical durability of a fluidized version of Phillips Petroleum Company`s proprietary Z-SORB sorbent for the desulfurization of coal-derived gases in a high-pressure (20 atm) fluidized-bed reactor under simulated U-Gas conditions and at a moderate operating temperature of 538 degrees C.

Seventh BES (Basic Energy Sciences) catalysis and surface chemistry research conference

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

Not Available

1990-03-01

Research programs on catalysis and surface chemistry are presented. A total of fifty-seven topics are included. Areas of research include heterogeneous catalysis; catalysis in hydrogenation, desulfurization, gasification, and redox reactions; studies of surface properties and surface active sites; catalyst supports; chemical activation, deactivation; selectivity, chemical preparation; molecular structure studies; sorption and dissociation. Individual projects are processed separately for the data bases. (CBS)

Purification, Characterization, and Overexpression of Flavin Reductase Involved in Dibenzothiophene Desulfurization by Rhodococcus erythropolis D-1

PubMed Central

Matsubara, Toshiyuki; Ohshiro, Takashi; Nishina, Yoshihiro; Izumi, Yoshikazu

2001-01-01

The dibenzothiophene (DBT)-desulfurizing bacterium, Rhodococcus erythropolis D-1, removes sulfur from DBT to form 2-hydroxybiphenyl using four enzymes, DszC, DszA, DszB, and flavin reductase. In this study, we purified and characterized the flavin reductase from R. erythropolis D-1 grown in a medium containing DBT as the sole source of sulfur. It is conceivable that the enzyme is essential for two monooxygenase (DszC and DszA) reactions in vivo. The purified flavin reductase contains no chromogenic cofactors and was found to have a molecular mass of 86 kDa and four identical 22-kDa subunits. The enzyme catalyzed NADH-dependent reduction of flavin mononucleotide (FMN), and the Km values for NADH and FMN were 208 and 10.8 μM, respectively. Flavin adenine dinucleotide was a poor substrate, and NADPH was inert. The enzyme did not catalyze reduction of any nitroaromatic compound. The optimal temperature and optimal pH for enzyme activity were 35°C and 6.0, respectively, and the enzyme retained 30% of its activity after heat treatment at 80°C for 30 min. The N-terminal amino acid sequence of the purified flavin reductase was identical to that of DszD of R. erythropolis IGTS8 (K. A. Gray, O. S. Pogrebinsky, G. T. Mrachko, L. Xi, D. J. Monticello, and C. H. Squires, Nat. Biotechnol. 14:1705–1709, 1996). The flavin reductase gene was amplified with primers designed by using dszD of R. erythropolis IGTS8, and the enzyme was overexpressed in Escherichia coli. The specific activity in crude extracts of the overexpressed strain was about 275-fold that of the wild-type strain. PMID:11229908

The impact of wet flue gas desulfurization scrubbing on mercury emissions from coal-fired power stations.

PubMed

Niksa, Stephen; Fujiwara, Naoki

2005-07-01

This article introduces a predictive capability for Hg retention in any Ca-based wet flue gas desulfurization (FGD) scrubber, given mercury (Hg) speciation at the FGD inlet, the flue gas composition, and the sulphur dioxide (SO2) capture efficiency. A preliminary statistical analysis of data from 17 full-scale wet FGDs connects flue gas compositions, the extents of Hg oxidation at FGD inlets, and Hg retention efficiencies. These connections clearly signal that solution chemistry within the FGD determines Hg retention. A more thorough analysis based on thermochemical equilibrium yields highly accurate predictions for total Hg retention with no parameter adjustments. For the most reliable data, the predictions were within measurement uncertainties for both limestone and Mg/lime systems operating in both forced and natural oxidation mode. With the U.S. Environmental Protection Agency's (EPA) Information Collection Request (ICR) database, the quantitative performance was almost as good for the most modern FGDs, which probably conform to the very high SO2 absorption efficiencies assumed in the calculations. The large discrepancies for older FGDs are tentatively attributed to the unspecified SO2 capture efficiencies and operating temperatures and to the possible elimination of HCl in prescrubbers. The equilibrium calculations suggest that Hg retention is most sensitive to inlet HCl and O2 levels and the FGD temperature; weakly dependent on SO2 capture efficiency; and insensitive to HgCl2, NO, CA:S ratio, slurry dilution level in limestone FGDs, and MgSO3 levels in Mg/lime systems. Consequently, systems with prescrubbers to eliminate HCl probably retain less Hg than fully integrated FGDs. The analysis also predicts re-emission of Hg(O) but only for inlet O2 levels that are much lower than those in full-scale FGDs.

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

Elmore, B.B.

As an alternative to post-combustion desulfurization of coal and pre-combustion desulfurization using physicochemical techniques, the microbial desulfurization of coal may be accomplished through the use of microbial cultures that, in an application of various microbial species, may remove both the pyritic and organic fractions of sulfur found in coal. Organisms have been isolated that readily depyritize coal but often at prohibitively low rates of desulfurization. Microbes have also been isolated that may potentially remove the organic-sulfur fraction present in coal (showing promise when acting on organic sulfur model compounds such as dibenzothiophene). The isolation and study of microorganisms demonstrating amore » potential for removing organic sulfur from coal has been undertaken in this project. Additionally, the organisms and mechanisms by which coal is microbially depyritized has been investigated. Three cultures were isolated that grew on dibenzothiophene (DBT), a model organic-sulfur compound, as the sole sulfur source. These cultures (UMX3, UMX9, and IGTS8) also grew on coal samples as the sole sulfur source. Numerous techniques for pretreating and ``cotreating`` coal for depyritization were also evaluated for the ability to improve the rate or extent of microbial depyritization. These include prewashing the coal with various solvents and adding surfactants to the culture broth. Using a bituminous coal containing 0.61% (w/w) pyrite washed with organic solvents at low slurry concentrations (2% w/v), the extent of depyritization was increased approximately 25% in two weeks as compared to controls. At slurry concentrations of 20% w/v, a tetrachloroethylene treatment of the coal followed by depyritization with Thiobacillus ferrooxidans increased both the rate and extent of depyritization by approximately 10%.« less

Transport and Transformation of Selenium and Other Constituents of Flue-Gas Desulfurization Wastewater in Water-Saturated Soil Materials.

PubMed

Galkaduwa, Madhubhashini B; Hettiarachchi, Ganga M; Kluitenberg, Gerard J; Hutchinson, Stacy L; Davis, Lawrence; Erickson, Larry E

2017-03-01

Constructed wetland treatment systems are used to remove selenium (Se) from flue-gas desulfurization (FGD) wastewater (WW). However, direct confirmation of the mechanism responsible for FGD WW Se retention in soil is lacking. A laboratory-based soil column study was performed to develop an evidence-based mechanism of Se retention and to study the behavior and the retention capacity of FGD WW constituents in water-saturated soil. A deoxygenated 1:1 mixture of FGD WW and raw water was delivered to the columns bottom-up at a flux of 1.68 cm d for 100 d. Some of the columns were flushed with the raw water at the same rate for an additional 100 d. Column effluent was analyzed for constituents of concern. Results showed a complete retention of FGD WW Se in the soil materials. Boron and fluorine were partially retained; however, sulfur, sodium, and chlorine retention was poor, agreeing with field observations. The FGD WW Se was retained in soil near the inlet end of the columns, indicating its limited mobility under reduced conditions. Sequential extraction procedure revealed that retained Se was mainly sequestered as stable/residual forms. Bulk- and micro-X-ray absorption near-edge structure spectroscopy confirmed that Se was mainly retained as reduced/stable species [Se(IV), organic Se, and Se(0)]. This study provides direct evidence for FGD WW Se retention in water-saturated soil via the transformation of oxidized Se into reduced/stable forms. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Selective catalytic oxidation: a new catalytic approach to the desulfurization of natural gas and liquid petroleum gas for fuel cell reformer applications

NASA Astrophysics Data System (ADS)

Lampert, J.

In both natural gas and liquid petroleum gas (LPG), sulfur degrades the performance of the catalysts used in fuel reformers and fuel cells. In order to improve system performance, the sulfur must be removed to concentrations of less than 200 ppbv (in many applications to less than 20 ppbv) before the fuel reforming operation. Engelhard Corporation presents a unique approach to the desulfurization of natural gas and LPG. This new method catalytically converts the organic and inorganic sulfur species to sulfur oxides. The sulfur oxides are then adsorbed on a high capacity adsorbent. The sulfur compounds in the fuel are converted to sulfur oxides by combining the fuel with a small amount of air. The mixture is then heated from 250 to 270 °C, and contacted with a monolith supported sulfur tolerant catalyst at atmospheric pressure. When Engelhard Corporation demonstrated this catalytic approach in the laboratory, the result showed sulfur breakthrough to be less than 10 ppbv in the case of natural gas, and less than 150 ppbv for LPG. We used a simulated natural gas and LPG mixture, doped with a 50-170 ppmv sulfur compound containing equal concentrations of COS, ethylmercaptan, dimethylsulfide, methylethylsulfide and tetrahydrothiophene. There is no need for recycled H 2 as in the case for hydrodesulfurization.

Novel Aldo-Keto Reductases for the Biocatalytic Conversion of 3-Hydroxybutanal to 1,3-Butanediol: Structural and Biochemical Studies

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

Kim, Taeho; Flick, Robert; Brunzelle, Joseph

structural determinants necessary for high activity in the biosynthesis of 1,3-BDO. This work expands our understanding of the molecular mechanisms of the substrate selectivity of aldo-keto reductases and demonstrates the potential for protein engineering of these enzymes for applications in the biocatalytic production of 1,3-BDO and other valuable chemicals.« less

[Tampa Electric Company IGCC project]. 1996 DOE annual technical report, January--December 1996

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

NONE

1997-12-31

Tampa Electric Company`s Polk Power Station Unit 1 (PPS-1) Integrated Gasification Combined Cycle (IGCC) demonstration project uses a Texaco pressurized, oxygen-blown, entrained-flow coal gasifier to convert approximately 2,000 tons per day of coal to syngas. The gasification plant is coupled with a combined cycle power block to produce a net 250 MW electrical power output. Coal is slurried in water, combined with 95% pure oxygen from an air separation unit, and sent to the gasifier to produce a high temperature, high pressure, medium-Btu syngas with a heat content of about 250 BTUs/cf (HHV). The syngas then flows through a highmore » temperature heat recovery unit which cools the syngas prior to its entering the cleanup systems. Molten coal ash flows from the bottom of the high temperature heat recovery unit into a water-filled quench chamber where it solidifies into a marketable slag by-product. Approximately 10% of the raw, hot syngas at 900 F is designed to pass through an intermittently moving bed of metal-oxide sorbent which removes sulfur-bearing compounds from the syngas. PPS-1 will be the first unit in the world to demonstrate this advanced metal oxide hot gas desulfurization technology on a commercial unit. The emphasis during 1996 centered around start-up activities.« less

Research Policy in the Federal Republic of Germany.

DTIC Science & Technology

1980-12-16

particularly for coal use, flue gas decontamination (particularly for desulfurization ), sewage treatment, biological pest control , and artificial fertilizers...NAME AND AODRESS 10. PROGRAM ELEMENT. PROJECT. TASK AREA 8 WORK UNIT NUMBERS 11. CONTROLLING OFFICE NAME AND ADDRESS 12. REPORT DATE 16 December 198 0...34 1" NUMSER-OF PAGES 14. MONITORING AGENCY NAME & ADDRESS(If different fromt Controlling Office) 15. SECURITY CLASS. (o this repol) Unclassified

Metals in Soil and Runoff from a Piedmont Hay Field Amended with Broiler Litter and Flue Gas Desulfurization Gypsum.

PubMed

Schomberg, Harry H; Endale, Dinku M; Jenkins, Michael B; Chaney, Rufus L; Franklin, Dorcas H

2018-03-01

Flue gas desulfurization gypsum (FGDG) from coal-fired power plants is readily available for agricultural use in many US regions. Broiler litter (BL) provides plant available N, P, and K but can be a source of unwanted As, Cu, and Zn. As a source of Ca and S, FGDG can reduce losses of P and other elements in runoff from BL-amended areas. Rainfall simulation plots (2.0 m) were established on a Piedmont Cecil soil growing 'Coastal' bermudagrass ( L.) for hay. Accumulation and transport of As, Cu, Cd, Cr, Hg, Pb, and Zn were evaluated after annual BL applications (13.5 Mg ha) with four FGDG rates (0, 2.2, 4.5, 9.0 Mg ha) and two FGDG treatments (0 and 9 Mg ha) without BL. Runoff As concentrations were sixfold greater with BL than without ( ≤ 0.01) and were similar to BL with FGDG at 2.2, 4.5 or 9.0 Mg ha ( ≤ 0.10). Runoff concentrations of target elements did not increase where FGDG was applied alone. After three annual applications of FGDG and BL, soil concentrations of As, Cr, Pb, Hg, and Cu were well below levels of environmental concern. Our findings indicate that runoff losses of As from BL application are not reduced with FGDG but support other research indicating no identifiable environmental risks from FGDG beneficial use in agricultural systems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Dry flue gas desulfurization by-product application effects on plant uptake and soil storage changes in a managed grassland.

PubMed

Burgess-Conforti, Jason R; Brye, Kristofor R; Miller, David M; Pollock, Erik D; Wood, Lisa S

2018-02-01

Environmental regulations mandate that sulfur dioxide (SO 2 ) be removed from the flue gases of coal-fired power plants, which results in the generation of flue gas desulfurization (FGD) by-products. These FGD by-products may be a viable soil amendment, but the large amounts of trace elements contained in FGD by-products are potentially concerning. The objective of this study was to evaluate the effects of land application of a high-Ca dry FGD (DFGD) by-product on trace elements in aboveground biomass and soil. A high-Ca DFGD by-product was applied once at a rate of 9 Mg ha -1 on May 18, 2015 to small plots with mixed-grass vegetation. Soil and biomass were sampled prior to application and several times thereafter. Aboveground dry matter and tissue As, Co, Cr, Hg, Se, U, and V concentrations increased (P < 0.05) following application, but did not differ (P > 0.05) from pre-application levels or the unamended control within 3 to 6 months of application. Soil pH in the amended treatment 6 months after application was greater (P < 0.05) than in the unamended control. Soil Ca, S, and Na contents also increased (P < 0.05), following by-product application compared to the unamended control. High-Ca DFGD by-products appear to be useful as a soil amendment, but cause at least a temporary increase in tissue concentrations of trace elements, which may be problematic for animal grazing situations.

Survey of Microcleaning Methods for Application to Army Coal-Fired Plants

DTIC Science & Technology

1989-02-01

Authority (TVA) has successfully reduced its cost of controlling SOX by combining postcombustion flue gas desulfurization equipment with precombustion coal...effective way of meeting the new standards for SOl Several options are available, in- cluding flue gas desulfurization , fluidized bed combustors, and...are available, including flue gas desulfurization , fluidized bed combustors, and precombustion cleaning. This report (Cont’d.) 20 DISTRIBUTION

Production of Jet Fuels from Coal Derived Liquids. Volume 10. Jet Fuels Production By-Products, Utility and Sulfur Emissions Control Integration Study

DTIC Science & Technology

1989-06-01

FLUE GAS DESULFURIZATION EVALUATION A-1/A-2 3-1. 3 BOILER STACK EMISSION CONTROL WITH...Appendices A - BACT Flue Gas Desulfurization Evaluation B - BACT Off- Gas Refrigeration Evaluation v LIST OF FIGURES Figure Page 1. Material Balance for...2. Desulfurize the flue gases from the Riley boilers when firing with high sulfur oils or lignite. Options in this category include commercial wet

Oxidative degradation stability and hydrogen sulfide removal performance of dual-ligand iron chelate of Fe-EDTA/CA.

PubMed

Miao, Xinmei; Ma, Yiwen; Chen, Zezhi; Gong, Huijuan

2017-09-05

Catalytic oxidation desulfurization using chelated iron catalyst is an effective method to remove H 2 S from various gas streams including biogas. However, the ligand of ethylenediaminetetraacetic acid (EDTA), which is usually adopted to prepare chelated iron catalyst, is liable to be oxidative degraded, and leads to the loss of desulfurization performance. In order to improve the degradation stability of the iron chelate, a series of iron chelates composed of two ligands including citric acid (CA) and EDTA were prepared and the oxidative degradation stability as well as desulfurization performance of these chelated iron catalysts were studied. Results show that the iron chelate of Fe-CA is more stable than Fe-EDTA, while for the desulfurization performance, the situation is converse. For the dual-ligand iron chelates of Fe-EDTA/CA, with the increase of mol ratio of CA to EDTA in the iron chelate solution, the oxidative degradation stability increased while the desulfurization performance decreased. The results of this work showed that Fe-EDTA/CA with a mol ratio of CA:EDTA = 1:1 presents a relative high oxidative degradation stability and an acceptable desulfurization performance with over 90% of H 2 S removal efficiency.

Biodesulfurization of refractory organic sulfur compounds in fossil fuels.

PubMed

Soleimani, Mehran; Bassi, Amarjeet; Margaritis, Argyrios

2007-01-01

The stringent new regulations to lower sulfur content in fossil fuels require new economic and efficient methods for desulfurization of recalcitrant organic sulfur. Hydrodesulfurization of such compounds is very costly and requires high operating temperature and pressure. Biodesulfurization is a non-invasive approach that can specifically remove sulfur from refractory hydrocarbons under mild conditions and it can be potentially used in industrial desulfurization. Intensive research has been conducted in microbiology and molecular biology of the competent strains to increase their desulfurization activity; however, even the highest activity obtained is still insufficient to fulfill the industrial requirements. To improve the biodesulfurization efficiency, more work is needed in areas such as increasing specific desulfurization activity, hydrocarbon phase tolerance, sulfur removal at higher temperature, and isolating new strains for desulfurizing a broader range of sulfur compounds. This article comprehensively reviews and discusses key issues, advances and challenges for a competitive biodesulfurization process.

Hydrodesulfurization of chlorinized coal

NASA Technical Reports Server (NTRS)

Kalvinskas, J. J.; Rohatgi, N. K. (Inventor)

1983-01-01

A method of desulfurization is described in which high sulfur coals are desulfurized by low temperature chlorinolysis of coal in liquid media, preferably water, followed by hydrodesulfurization at a temperature above 500 C. The coals are desulfurized to an extent of up to 90% by weight and simultaneously dechlorinated to a chlorine content below 0.1% by weight. The product coals have lower volatiles loss, lower oxygen and nitrogen content and higher fixed carbon than raw coals treated with hydrogen under the same conditions. Heating the chlorinated coal to a temperature above 500 C. in inert gas such as nitrogen results in significantly less desulfurization.

Carrier Battle Group (CVBG) Homeporting in the Puget Sound Area, Washington State. Volume 1. Chapters 1-12.

DTIC Science & Technology

1986-11-01

Various setting agents have been used to treat industrial wastes and flue gas desulfurization sludges. These include cement, lime, kiln dust, blast furnace...will determine the type of leachate control strategy that can be successfully implemented. Potential leachate control strategies include site selection...AND ADDRESS 10. PROGRAM ELEMENT, PROJECT, TASK same AREA & WORK UNIT NUMBERS 1I. CONTROLLING OFFICE NAME AND ADDRESS 12. REPORT DATE U.S. Army Corps

Software Development for Decision Analysis

DTIC Science & Technology

1975-03-01

to p Pollution Cost/lb Sulfur Emitted ( Flue Gas Desulfurization ) 178 3.11 Sensitivity of Total Societal Cost/KWH to...34 and "FGD ( flue gas desulfurization ) technology" have all been represented. The branching structure shown in Figure 3.7 (and for that matter each... Gas Desulfurization ) technol- ogy" are decision variables representing possible means of sulfur oxide emission control avallabie for the electric

The U.S. Energy Dilemma: The Gap between Today’s Requirements and Tomorrow’s Potential.

DTIC Science & Technology

1973-07-01

Possible Solutions . ........ .. 142 Use of Low-Sulfur Coal ................ 43 Flue - Gas Desulfurization ................ 43 Coal Cleaning...1) use of low-sulfur coal, (2) flue - gas desulfurization , (3) coal cleaning, (4) coal refining, and (5) coal conversion. Use of Low-Sulfur Coal The...to the same point (Skillings Mining Rev., 1973). Flue - Gas Desulfurization With standards based on sulfur dioxide emissions per million Btu, rather than

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

Study of Cleanliness of High Nitrogen Steel in ESR

NASA Astrophysics Data System (ADS)

Xuwei, Tang; Rong, Zhu

This paper compares inclusions in high nitrogen steel before and after ESR process, analyzes the influence of slag systems and total oxygen content in consumable ingots. The total oxygen content is reduced apparently during ESR process, which indicates good effects on removal of inclusions. In the experiment, it shows that different slag systems will affect the result of inclusions removal significantly; proper w(CaO/Al2O3) will reduce the level of inclusions and total oxygen content in ESR ingots. In ESR process, the type and chemical composition of inclusions have no difference when oxygen content in consumable ingots is different, which means O content in consumable ingots have no direct relationship with cleanliness of ESR ingots. In typical inclusions, w(MnO)/w(MnO+Al2O3)≈0.23 0.32. The total oxygen content of ESR ingots keeps between 20 30ppm when the oxygen contents in consumable ingots are diverse from 40 to 100ppm. Meanwhile, this paper studies desulfurization process of high nitrogen steel in ESR, analyzes the influence of slag systems a nd remelting rates on desulfurization efficiency. The results indicate that the average size and quant ity of sulfide inclusion decrease after ESR process. The typical inclusion after ESR process is MnS+Al2O3. Slag system with proper CaO content has higher sulfur partition ratio, which leads to better desulfurization effect. The desulfurization rate changes greatly with different remelting rates, which indicates the kinetic parameter has more influence in desulfurization. The reason of this phenomenon is that the process of desulfurization can be considered as a non-equilibrium reaction, which differs with thermodynamic equilibrium. In kinetic study, it is founded that the desulfurization efficiency increases with higher remelting area, sulfur partition and lower remelting rate, which is different from experiment. The desulfurization efficiency decreases firstly and then recovers when remelting rate drops. The

Highly Attrition Resistant Zinc Oxide-Based Sorbents for H2S Removal by Spray Drying Technique

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

Ryu, C.K.; Lee, J.B.; Ahn, D.H.

2002-09-19

Primary issues for the fluidized-bed/transport reactor process are high attrition resistant sorbent, its high sorption capacity and regenerability, durability, and cost. The overall objective of this project is the development of a superior attrition resistant zinc oxide-based sorbent for hot gas cleanup in integrated coal gasification combined cycle (IGCC). Sorbents applicable to a fluidized-bed hot gas desulfurization process must have a high attrition resistance to withstand the fast solid circulation between a desulfurizer and a regenerator, fast kinetic reactions, and high sulfur sorption capacity. The oxidative regeneration of zinc-based sorbent usually initiated at greater than 600 C with highly exothermicmore » nature causing deactivation of sorbent as well as complication of sulfidation process by side reaction. Focusing on solving the sorbent attrition and regenerability of zinc oxide-based sorbent, we have adapted multi-binder matrices and direct incorporation of regeneration promoter. The sorbent forming was done with a spray drying technique that is easily scalable to commercial quantity.« less

Confocal Raman Microscopy for the Determination of Protein and Quaternary Ammonium Ion Loadings in Biocatalytic Membranes for Electrochemical Energy Conversion and Storage

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

Cai, Rong; Abdellaoui, Sofiene; Kitt, Jay P.

Here, the need to immobilize active enzyme, while ensuring high rates of substrate turnover and electronic charge transfer with an electrode, is a centrally important challenge in the field of bioelectrocatalysis. In this work, we demonstrate the use of confocal Raman microscopy as a tool for quantitation and molecular-scale structural characterization of ionomers and proteins within biocatalytic membranes to aid in the development of energy efficient biofuel cells. A set of recently available short side chain Aquivion ionomers spanning a range of equivalent weight (EW) suitable for enzyme immobilization was investigated. Aquivion ionomers (790 EW, 830 EW and 980 EW)more » received in the proton-exchanged (SO 3H) form were treated with tetra-n-butylammonium bromide (TBAB) to neutralize the ionomer and expand the size of ionic domains for enzyme incorporation. Through the use of confocal Raman microscopy, membrane TBA+ ion content was predicted in calibration studies to within a few percent of the conventional titrimetric method across the full range of TBA + : SO 3 - ratios of practical interest (0.1 to 1.7). Protein incorporation into membranes was quantified at the levels expected in biofuel cell electrodes. Furthermore, features associated with the catalytically active, enzyme-coordinated copper center were evident between 400 cm -1 - 500 cm -1 in spectra of laccase catalytic membranes, demonstrating the potential to interrogate mechanistic chemistry at the enzyme active site of biocathodes under fuel cell reaction conditions. When benchmarked against the 1100 EW Nafion ionomer in glucose/air enzymatic fuel cells (EFCs), EFCs with laccase air-breathing cathodes prepared from TBA + modified Aquivion ionomers were able to reach maximum power densities (P max) up to 1.5 times higher than EFCs constructed with cathodes prepared from TBA + modified Nafion. The improved performance of EFCs containing the short side chain Aquivion ionomers relative to Nafion is

Confocal Raman Microscopy for the Determination of Protein and Quaternary Ammonium Ion Loadings in Biocatalytic Membranes for Electrochemical Energy Conversion and Storage

DOE PAGES

Cai, Rong; Abdellaoui, Sofiene; Kitt, Jay P.; ...

2017-11-14

Here, the need to immobilize active enzyme, while ensuring high rates of substrate turnover and electronic charge transfer with an electrode, is a centrally important challenge in the field of bioelectrocatalysis. In this work, we demonstrate the use of confocal Raman microscopy as a tool for quantitation and molecular-scale structural characterization of ionomers and proteins within biocatalytic membranes to aid in the development of energy efficient biofuel cells. A set of recently available short side chain Aquivion ionomers spanning a range of equivalent weight (EW) suitable for enzyme immobilization was investigated. Aquivion ionomers (790 EW, 830 EW and 980 EW)more » received in the proton-exchanged (SO 3H) form were treated with tetra-n-butylammonium bromide (TBAB) to neutralize the ionomer and expand the size of ionic domains for enzyme incorporation. Through the use of confocal Raman microscopy, membrane TBA+ ion content was predicted in calibration studies to within a few percent of the conventional titrimetric method across the full range of TBA + : SO 3 - ratios of practical interest (0.1 to 1.7). Protein incorporation into membranes was quantified at the levels expected in biofuel cell electrodes. Furthermore, features associated with the catalytically active, enzyme-coordinated copper center were evident between 400 cm -1 - 500 cm -1 in spectra of laccase catalytic membranes, demonstrating the potential to interrogate mechanistic chemistry at the enzyme active site of biocathodes under fuel cell reaction conditions. When benchmarked against the 1100 EW Nafion ionomer in glucose/air enzymatic fuel cells (EFCs), EFCs with laccase air-breathing cathodes prepared from TBA + modified Aquivion ionomers were able to reach maximum power densities (P max) up to 1.5 times higher than EFCs constructed with cathodes prepared from TBA + modified Nafion. The improved performance of EFCs containing the short side chain Aquivion ionomers relative to Nafion is

Electrochemical generation of sulfur vacancies in the basal plane of MoS2 for hydrogen evolution

PubMed Central

Tsai, Charlie; Li, Hong; Park, Sangwook; Park, Joonsuk; Han, Hyun Soo; Nørskov, Jens K.; Zheng, Xiaolin; Abild-Pedersen, Frank

2017-01-01

Recently, sulfur (S)-vacancies created on the basal plane of 2H-molybdenum disulfide (MoS2) using argon plasma exposure exhibited higher intrinsic activity for the electrochemical hydrogen evolution reaction than the edge sites and metallic 1T-phase of MoS2 catalysts. However, a more industrially viable alternative to the argon plasma desulfurization process is needed. In this work, we introduce a scalable route towards generating S-vacancies on the MoS2 basal plane using electrochemical desulfurization. Even though sulfur atoms on the basal plane are known to be stable and inert, we find that they can be electrochemically reduced under accessible applied potentials. This can be done on various 2H-MoS2 nanostructures. By changing the applied desulfurization potential, the extent of desulfurization and the resulting activity can be varied. The resulting active sites are stable under extended desulfurization durations and show consistent HER activity. PMID:28429782

Electrochemical generation of sulfur vacancies in the basal plane of MoS2 for hydrogen evolution

DOE PAGES

Tsai, Charlie; Li, Hong; Park, Sangwook; ...

2017-04-21

Recently, sulfur (S)-vacancies created on the basal plane of 2H-molybdenum disulfide (MoS 2) using argon plasma exposure exhibited higher intrinsic activity for the electrochemical hydrogen evolution reaction than the edge sites and metallic 1T-phase of MoS 2 catalysts. But, a more industrially viable alternative to the argon plasma desulfurization process is needed. In this work, we introduce a scalable route towards generating S-vacancies on the MoS 2 basal plane using electrochemical desulfurization. We found that they can be electrochemically reduced under accessible applied potentials, even though sulfur atoms on the basal plane are known to be stable and inert. Thismore » can be done on various 2H-MoS 2 nanostructures. Furthermore, by changing the applied desulfurization potential, the extent of desulfurization and the resulting activity can be varied. The resulting active sites are stable under extended desulfurization durations and show consistent HER activity.« less

Central Heating Plant Coal Use Handbook. Volume 1: Technical Reference.

DTIC Science & Technology

1996-11-01

variation of a dry desulfurization system simply uses dry calcium hydroxide that is injected into the flue gas stream before entry to a fabric filter...97/14, Voll 173 competitive capital and operating costs compared with conventional technology using flue gas desulfurization reduced NOx emissions...ferric iron in slag, expressed as a percentage of the total iron calculated as ferric iron FGD: Flue gas desulfurization filter: A device for

Coal Liquids: Manufacture and Properties. A Review.

DTIC Science & Technology

1982-09-01

a conventional furnace with flue gas desulfurization ; however, its use as a boiler fuel is not economical at present. Research continues on...J.B., "The Shell Flue Gas Desulfurization Process," Universal Oil Products Process Division, Universal Oil Products, Inc., Des Plaines, IL, presented...in 1980, H-Coal and EDS process, gasification obstacles. 187. Salmeczi, J.G., " Flue Gas Desulfurization by the ThiosorbicC Process," Dravo Time Company

East Europe Report, Economic and Industrial Affairs

DTIC Science & Technology

1984-08-20

plant with wet desulfurization of flue gas . This method was pre- viously only successful with hard coal. Before the end of this year a large- scale...REPUBLIC DM 40 Million Euro Credit to Foreign Trade Organization (HANDELSBLATT, 2 Jul 84) 21 Minister Interested in Flue Gas Desulfurization Equipment...Zurich and the Rhein-Saar-Lux AG. 12644 CSO: 2300/565 21 GERMAN DEMOCRATIC REPUBLIC MINISTER INTERESTED IN FLUE GAS DESULFURIZATION EQUIPMENT

Air Emissions Inventory Guidance Document for Stationary Sources at Air Force Installations.

DTIC Science & Technology

1999-05-01

small stoker-fired boilers). sox Change to lower sulfur coal, Coal Cleaning, Flue Gas Desulfurization (e.g., wet scrubbing, spray drying, furnace...Multiclone Collector. SOx Flue Gas Desulfurization (e.g., wet , semi-dry, or dry scrubbers) NOx Low Excess Air, Burners out of Service, Biased Burner...both flue gas desulfurization spray dryer adsorber (FGD-SDA) and a fabric filter (FF). d Factors apply to boilers equipped with an electrostatic

Fuel-Burning Technology Alternatives for the Army.

DTIC Science & Technology

1985-01-01

control 0.85 2,287,000 Flue gas desulfurization 0.68 3,410,000 Total 12,478,000 *Capital cost estimate...34......... . . Particulate and sulfur dioxide control are needed. A baghouse and flue gas desulfurization (FD) scrubber system must be installed. Each item’s cost in...direct cost) Contingency (20% of 1,253,000 direct and indirect costs) Subtotal 7,518,000 Particulate control 1,342,000 Flue gas desulfurization

Continuous desulfurization and bacterial community structure of an integrated bioreactor developed to treat SO2 from a gas stream.

PubMed

Lin, Jian; Li, Lin; Ding, Wenjie; Zhang, Jingying; Liu, Junxin

2015-11-01

Sulfide dioxide (SO2) is often released during the combustion processes of fossil fuels. An integrated bioreactor with two sections, namely, a suspended zone (SZ) and immobilized zone (IZ), was applied to treat SO2 for 6months. Sampling ports were set in both sections to investigate the performance and microbial characteristics of the integrated bioreactor. SO2 was effectively removed by the synergistic effect of the SZ and IZ, and more than 85% removal efficiency was achieved at steady state. The average elimination capacity of SO2 in the bioreactor was 2.80g/(m(3)·hr) for the SZ and 1.50g/(m(3)·hr) for the IZ. Most SO2 was eliminated in the SZ. The liquid level of the SZ and the water content ratio of the packing material in the IZ affected SO2 removal efficiency. The SZ served a key function not only in SO2 elimination, but also in moisture maintenance for the IZ. The desired water content in IZ could be feasibly maintained without any additional pre-humidification facilities. Clone libraries of 16S rDNA directly amplified from the DNA of each sample were constructed and sequenced to analyze the community composition and diversity in the individual zones. The desulfurization bacteria dominated both zones. Paenibacillus sp. was present in both zones, whereas Ralstonia sp. existed only in the SZ. The transfer of SO2 to the SZ involved dissolution in the nutrient solution and biodegradation by the sulfur-oxidizing bacteria. This work presents a potential biological treatment method for waste gases containing hydrophilic compounds. Copyright © 2015. Published by Elsevier B.V.

Biocatalysis in the Pharmaceutical Industry: The Need for Speed.

PubMed

Truppo, Matthew D

2017-05-11

The use of biocatalysis in the pharmaceutical industry continues to expand as a result of increased access to enzymes and the ability to engineer those enzymes to meet the demands of industrial processes. However, we are still just scratching the surface of potential biocatalytic applications. The time pressures present in pharmaceutical process development are incompatible with the long lead times required for engineering a suitable biocatalyst. Dramatic increases in the speed of protein engineering are needed to deliver on the ever increasing opportunities for industrial biocatalytic processes.

JPRS Report, Science & Technology. China: Energy.

DTIC Science & Technology

1992-12-24

desulfurization tech- nology at the present time. The wet method technology accounts for 86 percent of all of the world’s flue gas desulfurization facilities...Limestone-gypsum wet method desulfurization tech- nology Huaneng’s Luohuang Power Plant has already imported two sets of 360MW generator boiler flue gas ...Circulating Fluidized-Bed Technology Development [LinZhaokui, Wang Dun’en, et al; DONGLIGONGCHENG, 15 Oct 92] 27 Selection of Flue

Economic Analysis of Coal-Fired Cogeneration Plants for Air Force Bases

DTIC Science & Technology

1990-10-01

control . However, the existing stoker boilers at Griffiss AFB use lime scrubbers for flue gas desulfurization . The following input parameters were used to...boiler plant was newly installed in 1985 and is in excellent condition. Spray dryer scrubbers are used for flue gas desulfurization . 32 5.3.2 Heating Fuel...for stoker boilers in the previous heating plant studies, 1 ,3 and for sites that require flue gas desulfurization , an efficiency of 80% was used

Biocatalysis in the Pharmaceutical Industry: The Need for Speed

PubMed Central

2017-01-01

The use of biocatalysis in the pharmaceutical industry continues to expand as a result of increased access to enzymes and the ability to engineer those enzymes to meet the demands of industrial processes. However, we are still just scratching the surface of potential biocatalytic applications. The time pressures present in pharmaceutical process development are incompatible with the long lead times required for engineering a suitable biocatalyst. Dramatic increases in the speed of protein engineering are needed to deliver on the ever increasing opportunities for industrial biocatalytic processes. PMID:28523096

Monitoring of sulfur dioxide emission resulting from biogas utilization on commercial pig farms in Taiwan.

PubMed

Su, Jung-Jeng; Chen, Yen-Jung

2015-01-01

The objective of this work tends to promote methane content in biogas and evaluate sulfur dioxide emission from direct biogas combustion without desulfurization. Analytical results of biogas combustion showed that combustion of un-desulfurized biogas exhausted more than 92% of SO₂ (P < 0.01). In the meantime, more than 90% of hydrogen sulfide was removed during the combustion process using un-desulfurized biogas (P < 0.01). Those disappeared hydrogen sulfide may deposit on the surfaces of power generator's engines or burner heads of boilers. Some of them (4.6-9.1% of H₂S) were converted to SO₂ in exhaust gas. Considering the impacts to human health and living environment, it is better to desulfurize biogas before any applications.

Characterization of a newly synthesized carbonyl reductase and construction of a biocatalytic process for the synthesis of ethyl (S)-4-chloro-3-hydroxybutanoate with high space-time yield.

PubMed

You, Zhong-Yu; Liu, Zhi-Qiang; Zheng, Yu-Guo

2014-02-01

A carbonyl reductase (SCR2) gene was synthesized and expressed in Escherichia coli after codon optimization to investigate its biochemical properties and application in biosynthesis of ethyl (S)-4-chloro-3-hydroxybutanoate ((S)-CHBE), which is an important chiral synthon for the side chain of cholesterol-lowering drug. The recombinant SCR2 was purified and characterized using ethyl 4-chloro-3-oxobutanoate (COBE) as substrate. The specific activity of purified enzyme was 11.9 U mg(-1). The optimum temperature and pH for enzyme activity were 45 °C and pH 6.0, respectively. The half-lives of recombinant SCR2 were 16.5, 7.7, 2.2, 0.41, and 0.05 h at 30 °C, 35 °C, 40 °C, 45 °C, and 50 °C, respectively, and it was highly stable in acidic environment. This SCR2 displayed a relatively narrow substrate specificity. The apparent K m and V max values of purified enzyme for COBE are 6.4 mM and 63.3 μmol min(-1) mg(-1), respectively. The biocatalytic process for the synthesis of (S)-CHBE was constructed by this SCR2 in an aqueous-organic solvent system with a substrate fed-batch strategy. At the final COBE concentration of 1 M, (S)-CHBE with yield of 95.3% and e.e. of 99% was obtained after 6-h reaction. In this process, the space-time yield per gram of biomass (dry cell weight, DCW) and turnover number of NADP(+) to (S)-CHBE were 26.5 mmol L(-1) h(-1) g(-1) DCW and 40,000 mol/mol, respectively, which were the highest values as compared with other works.

Design and experimental study on desulphurization process of ship exhaust

NASA Astrophysics Data System (ADS)

Han, Mingyang; Hao, Shan; Zhou, Junbo; Gao, Liping

2018-02-01

This desulfurization process involves removing sulfur oxides with seawater or alkaline aqueous solutions and then treating the effluent by aeration and pH adjustment before discharging it into the ocean. In the desulfurization system, the spray tower is the key equipment and the venturi tubes are the pretreatment device. The two stages of plates are designed to fully absorb sulfur oxides in exhaust gases. The spiral nozzles atomize and evenly spray the desulfurizers into the tower. This study experimentally investigated the effectiveness of this desulfurization process and the factors influencing it under laboratory conditions, with a diesel engine exhaust used to represent ship exhaust. The experimental results show that this process can effectively absorb the SO2 in the exhaust. When the exhaust flow rate was 25 m3/h and the desulfurizer flow rate was 4 L/min, the sulfur removal efficiency (SRE) reached 99.7%. The flow rate, alkalinity, and temperature of seawater were found to have significant effects on the SRE. Adjusting seawater flow rate (SWR) and alkalinity within certain ranges can substantially improve the SRE.

H2S adsorption and decomposition on the gradually reduced α-Fe2O3(001) surface: A DFT study

NASA Astrophysics Data System (ADS)

Lin, Changfeng; Qin, Wu; Dong, Changqing

2016-11-01

Reduction of iron based desulfurizer occurs during hot gas desulfurization process, which will affect the interaction between H2S and the desulfurizer surface. In this work, a detailed adsorption behavior and dissociation mechanism of H2S on the perfect and reduced α-Fe2O3(001) surfaces, as well as the correlation between the interaction characteristic and reduction degree of iron oxide, have been studied by using periodic density functional theory (DFT) calculations. Results demonstrate that H2S firstly chemisorbs on surface at relatively higher oxidation state (reduction degree χ < 33%), then dissociative adsorption occurs and becomes the main adsorption type after χ > 33%. Reduction of iron oxide benefits the H2S adsorption. Further, dissociation processes of H2S via molecular and dissociative adsorption were investigated. Results show that after reduction of Fe2O3 into the oxidation state around FeO and Fe, the reduced surface exhibits very strong catalytic capacity for H2S decomposition into S species. Meanwhile, the overall dissociation process on all surfaces is exothermic. These results provide a fundamental understanding of reduction effect of iron oxide on the interaction mechanism between H2S and desulfurizer surface, and indicate that rational control of reduction degree of desulfurizer is essential for optimizing the hot gas desulfurization process.

Pressurized fluidized-bed hydroretorting of Eastern oil shales -- Sulfur control

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

Roberts, M.J.; Abbasian, J.; Akin, C.

1992-05-01

This topical report on Sulfur Control'' presents the results of work conducted by the Institute of Gas Technology (IGT), the Illinois Institute of Technology (IIT), and the Ohio State University (OSU) to develop three novel approaches for desulfurization that have shown good potential with coal and could be cost-effective for oil shales. These are (1) In-Bed Sulfur Capture using different sorbents (IGT), (2) Electrostatic Desulfurization (IIT), and (3) Microbial Desulfurization and Denitrification (OSU and IGT). The objective of the task on In-Bed Sulfur Capture was to determine the effectiveness of different sorbents (that is, limestone, calcined limestone, dolomite, and siderite)more » for capturing sulfur (as H{sub 2}S) in the reactor during hydroretorting. The objective of the task on Electrostatic Desulfurization was to determine the operating conditions necessary to achieve a high degree of sulfur removal and kerogen recovery in IIT's electrostatic separator. The objectives of the task on Microbial Desulfurization and Denitrification were to (1) isolate microbial cultures and evaluate their ability to desulfurize and denitrify shale, (2) conduct laboratory-scale batch and continuous tests to improve and enhance microbial removal of these components, and (3) determine the effects of processing parameters, such as shale slurry concentration, solids settling characteristics, agitation rate, and pH on the process.« less

Controlling enzymatic activity by immobilization on graphene oxide

NASA Astrophysics Data System (ADS)

Bolibok, Paulina; Wiśniewski, Marek; Roszek, Katarzyna; Terzyk, Artur P.

2017-04-01

In this study, graphene oxide (GO) has been applied as a matrix for enzyme immobilization. The protein adsorption capacity of GO is much higher than of other large surface area carbonaceous materials. Its structure and physicochemical properties are reported beneficial also for enzymatic activity modifications. The experimental proof was done here that GO-based biocatalytic systems with immobilized catalase are modifiable in terms of catalyzed reaction kinetic constants. It was found that activity and stability of catalase, considered here as model enzyme, closely depend on enzyme/GO ratio. The changes in kinetic parameters can be related to secondary structure alterations. The correlation between enzyme/GO ratio and kinetic and structure parameters is reported for the first time and enables the conscious control of biocatalytic processes and their extended applications. The biological activity of obtained biocatalytic systems was confirmed in vitro by the use of functional test. The addition of immobilized catalase improved the cells' viability after they were exposed to hydrogen peroxide and tert-butyl-hydroperoxide used as source of reactive oxygen species.

Enzymatic hybridization of α-lipoic acid with bioactive compounds in ionic solvents.

PubMed

Papadopoulou, Athena A; Katsoura, Maria H; Chatzikonstantinou, Alexandra; Kyriakou, Eleni; Polydera, Angeliki C; Tzakos, Andreas G; Stamatis, Haralambos

2013-05-01

The lipase-catalyzed molecular hybridization of α-lipoic acid (LA) with bioactive compounds pyridoxine, tyrosol and tyramine was performed in ionic solvents and deep eutectic solvents. The biocatalytic reactions were catalyzed by Candida antarctica lipase B immobilized onto various functionalized multi-walled carbon nanotubes (f-CNTs-CaLB), as well as by commercial Novozym 435. The use of f-CNTs-CaLB leads, in most cases, to higher conversion yields as compared to Novozym 435. The nature and ion composition of ionic solvents affect the performance of the biocatalytic process. The highest conversion yield was observed in (mtoa)NTf2. The high enzyme stability and the relatively low solubility of substrates in specific media account for the improved biocatalytic synthesis of molecular hybrids of LA. Principal component analysis was used to screen for potential lipoxygenase inhibitors. In vitro studies showed that the synthesized compounds exhibit up to 10-fold increased inhibitory activity on lipoxygenase mediated lipid peroxidation as compared to parent molecules. Copyright © 2013 Elsevier Ltd. All rights reserved.

New Bedford Harbor Superfund Project, Acushnet River Estuary Engineering Feasibility Study of Dredging and Dredged Material Disposal Alternatives. Report 9. Laboratory-Scale Application of Solidification/Stabilization Technology

DTIC Science & Technology

1989-01-01

force) per square inch to kilopascals, multiply by 6.894757. ** Flue - gas desulfurization . 27 1.0 sediment process, UCS measurements for solidified...Dredging Control Technoloqies 11 Evaluation of Conceptual Dredging and Disposal Alternatives 12 Executive Summary Destroy this report when no longer needed...solubility of metals by controlling the pH and alkalinity. Additional metal immobilization can be obtained by modify- ing the process to include

Technoeconomic Optimization of Waste Heat Driven Forward Osmosis for Flue Gas Desulfurization Wastewater Treatment

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

Gingerich, Daniel B; Bartholomew, Timothy V; Mauter, Meagan S

With the Environmental Protection Agency’s recent Effluent Limitation Guidelines for Steam Electric Generators, power plants are having to install and operate new wastewater technologies. Many plants are evaluating desalination technologies as possible compliance options. However, the desalination technologies under review that can reduce wastewater volume or treat to a zero-liquid discharges standard have a significant energy penalty to the plant. Waste heat, available from the exhaust gas or cooling water from coal-fired power plants, offers an opportunity to drive wastewater treatment using thermal desalination technologies. One such technology is forward osmosis (FO). Forward osmosis utilizes an osmotic pressure gradient tomore » passively pull water from a saline or wastewater stream across a semi-permeable membrane and into a more concentrated draw solution. This diluted draw solution is then fed into a distillation column, where the addition of low temperature waste heat can drive the separation to produce a reconcentrated draw solution and treated water for internal plant reuse. The use of low-temperature waste heat decouples water treatment from electricity production and eliminates the link between reducing water pollution and increasing air emissions from auxiliary electricity generation. In order to evaluate the feasibility of waste heat driven FO, we first build a model of an FO system for flue gas desulfurization (FGD) wastewater treatment at coal-fired power plants. This model includes the FO membrane module, the distillation column for draw solution recovery, and waste heat recovery from the exhaust gas. We then add a costing model to account for capital and operating costs of the forward osmosis system. We use this techno-economic model to optimize waste heat driven FO for the treatment of FGD wastewater. We apply this model to three case studies: the National Energy Technology Laboratory (NETL) 550 MW model coal fired power plant without

Effect of the Z- and Macro-R-Group on the Thermal Desulfurization of Polymers Synthesized with Acid/Base "Switchable" Dithiocarbamate RAFT Agents.

PubMed

Stace, Sarah J; Fellows, Christopher M; Moad, Graeme; Keddie, Daniel J

2018-05-11

Thermolysis is examined as a method for complete desulfurization of reversible addition-fragmentation chain transfer (RAFT)-synthesized polymers prepared with acid/base "switchable" N-methyl-N-pyridyldithiocarbamates [RS 2 CZ or RS 2 CZH + ]. Macro-RAFT agents from more activated monomers (MAMs) (i.e., styrene (St), N-isopropylacrylamide (NIPAm), and methyl methacrylate (MMA)) with RS 2 CZH + and less activated monomers (LAMs) (i.e., vinyl acetate (VAc) and N-vinylpyrolidone (NVP)) with RS 2 CZ are prepared by RAFT polymerization and analyzed by thermogravimetric analysis. In all cases, a mass loss consistent with loss of the end group (ZCS 2 H) is observed at temperatures lower than, and largely discrete from, that required for further degradation of the polymer. The temperatures for end group loss and the new end groups formed are strongly dependent on the identity of the R(P) n and the state of the pyridyl Z group; increasing in the series poly(MMA) < poly(St) ∼ poly(NIPAm) < poly(VAc) ∼ poly(NVP) for S 2 CZ and poly(MMA) < poly(St) ∼ poly(NIPAm) for S 2 CZH + . Clean end group removal is possible for poly(St) and poly(NVP). For poly(NIPAm), the thiocarbonyl chain end is removed, but the end group identity is less certain. For poly(MMA) and poly(VAc), some degradation of the polymer accompanies end group loss under the conditions used and further refinement of the process is required. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Simultaneous removal of SO2 and NOx from flue gas by wet scrubbing using a urea solution.

PubMed

Li, Ge; Wang, Baodong; Xu, Wayne Qiang; Li, Yonglong; Han, Yifan; Sun, Qi

2018-03-27

Nitrogen oxides (NO x ) and sulfur dioxide (SO 2 ) are major air pollutants, so simultaneously removing them from gases emitted during fossil fuel combustion in stationary systems is important. Wet denitrification using urea is used for a wide range of systems. Additives have strong effects on wet denitrification using urea, and different mechanisms are involved and different effects found using different additives. In this study, the effects of different additives, initial urea concentrations, reaction temperatures, initial pH values, gas flow rates, and reaction times on the simultaneous desulfurization and denitrification efficiencies achieved using wet denitrification using urea were studied in single factor experiment. The optimum reaction conditions for desulfurization and denitrification were found. Desulfurization and denitrification efficiencies of 97.5% and 96.3%, respectively, were achieved at a KMnO 4 concentration 5 mmol/L, a reaction temperature of 70°C, initial urea solution pH 8, a urea concentration of 9%, and a gas flow rate of 40 L/h. The concentrations of the desulfurization and denitrification reaction products in the solution were determined. NO x was mainly transformed into N 2 , and the [Formula: see text] and [Formula: see text] concentrations in the solution became very low. The reactions involved in SO 2 and NO x removal using urea were analyzed from the thermodynamic viewpoint. Increasing the temperature was not conducive to the reactions but increased the rate constant, so an optimum temperature was determined. The simultaneous desulfurization and denitrification kinetics were calculated. The urea consumption and [Formula: see text], [Formula: see text], and [Formula: see text] generation reactions were all zero order. The [Formula: see text] generation rate was greater than the [Formula: see text] generation rate. The simultaneous desulfurization and denitrification process and mechanism were studied. The results provide reference

Nonaqueous System of Iron-Based Ionic Liquid and DMF for the Oxidation of Hydrogen Sulfide and Regeneration by Electrolysis.

PubMed

Guo, Zhihui; Zhang, Tingting; Liu, Tiantian; Du, Jun; Jia, Bing; Gao, Shujing; Yu, Jiang

2015-05-05

To improve the hydrogen sulfide removal efficiency with the application of an iron-based imidazolium chloride ionic liquid (Fe(III)-IL) as desulfurizer, Fe(II) and N,N-dimethylformamide (DMF) are introduced to Fe(III)-IL to construct a new nonaqueous desulfurization system (Fe(III/II)-IL/DMF). Following desulfurization, the system can be regenerated using the controlled-potential electrolysis method. The addition of Fe(II) in Fe(III)-IL is beneficial for the hydrogen sulfide removal and the electrochemical regeneration of the desulfurizer. The addition of DMF in Fe(III/II)-IL does not change the structure of Fe(III/II)-IL but clearly decreases the acidity, increases the electrolytic current, and decreases the stability of the Fe-Cl bond in Fe(III/II)-IL. Fe(III/II)-IL/DMF can remove hydrogen sulfide and can be regenerated through an electrochemical method more efficiently than can Fe(III/II)-IL. After six cycles, the desulfurization efficiency remains higher than 98%, and the average conversion rate of Fe(II) is essentially unchanged. No sulfur peroxidation occurs, and the system remains stable. Therefore, this new nonaqueous system has considerable potential for removing H2S in pollution control applications.

The distribution and sea-air transfer of volatile mercury in waste post-desulfurization seawater discharged from a coal-fired power plant.

PubMed

Sun, Lumin; Lin, Shanshan; Feng, Lifeng; Huang, Shuyuan; Yuan, Dongxing

2013-09-01

The waste seawater discharged in coastal areas from coal-fired power plants equipped with a seawater desulfurization system might carry pollutants such as mercury from the flue gas into the adjacent seas. However, only very limited impact studies have been carried out. Taking a typical plant in Xiamen as an example, the present study targeted the distribution and sea-air transfer flux of volatile mercury in seawater, in order to trace the fate of the discharged mercury other than into the sediments. Samples from 28 sampling sites were collected in the sea area around two discharge outlets of the plant, daily and seasonally. Total mercury, dissolved gaseous mercury and dissolved total mercury in the seawater, as well as gaseous elemental mercury above the sea surface, were investigated. Mean concentrations of dissolved gaseous mercury and gaseous elemental mercury in the area were 183 and 4.48 ng m(-3) in summer and 116 and 3.92 ng m(-3) in winter, which were significantly higher than those at a reference site. Based on the flux calculation, the transfer of volatile mercury was from the sea surface into the atmosphere, and more than 4.4 kg mercury, accounting for at least 2.2 % of the total discharge amount of the coal-fired power plant in the sampling area (1 km(2)), was emitted to the air annually. This study strongly suggested that besides being deposited into the sediment and diluted with seawater, emission into the atmosphere was an important fate for the mercury from the waste seawater from coal-fired power plants.

Adsorption and desorption of sulfur dioxide on novel adsorbents for flue gas desulfurization. Final report, September 1, 1993--August 31, 1994

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

Lin, Y.S.

Dry regenerative sorption processes have recently attracted increasing attention in flue gas desulfurization (FGD) because of their several advantages over the conventional wet-scrubbing processes. Dry sorbents are usually made by coating a transition or alkaline earth metal precursor on the surface of a porous support. Major disadvantages of these sorbents prepared by the conventional methods include relatively poor attrition resistance and low SO{sub 2} sorption capacity. The physical and especially chemical attrition (associated with the sulphation-oxidation-reduction cycles in the process) deteriorates the performance of the sorbents. The low SO{sub 2} sorption capacity is primarily due to the small surface areamore » of the support. Materials with a high surface area are not used as the supports for FGD sorbents because these materials usually are not thermally stable at high temperatures. In the past year, the research supported by Ohio Coal Development Office was focused on synthesis and properties of sol-gel derived alumina and zeolite sorbents with improved properties for FGD. The sol-gel derived alumina has large surface area, mesopore size and excellent mechanical strength. Some alumina-free zeolites not only posses the basic properties required as a sorbent for FGD (hydrophobicity, thermal and chemical stability, mechanical strength) but also have extremely large surface area and selective surface chemistry. The major objectives of this research program were to synthesize the sol-gel derived sorbents and to explore the use of the zeolites either directly as adsorbents or as sorbent support for FGD. The research was aimed at developing novel FGD sorbents possessing better sorption equilibrium and kinetic properties and improved physical and chemical attrition resistance.« less

LIFAC Demonstration at Richmond Power and Light Whitewater Valley Unit No. 2 Volume II: Project Performance and Economics

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

None, None

The C1ean Coal Technology (CCT) Program has been recognized in the National Energy Strategy as a major initiative whereby coal will be able to reach its full potential as a source of energy for the nation and the international marketplace. Attainment of this goal depends upon the development of highly efficient, environmentally sound, competitive coal utilization technologies responsive to diverse energy markets and varied consumer needs. The CCT Program is an effort jointly funded by government and industry whereby the most promising of the advanced coal-based technologies are being moved into the marketplace through demonstration. The CCT Program is beingmore » implemented through a total of five competitive solicitations. LIFAC North America, a joint venture partnership of ICF Kaiser Engineers, Inc., and Tampella Power Corporation, is currently demonstrating the LIFAC flue gas desulfurization technology developed by Tampella Power. This technology provides sulfur dioxide emission control for power plants, especially existing facilities with tight space limitations. Sulfur dioxide emissions are expected to be reduced by up to 85% by using limestone as a sorbent. The LIFAC technology is being demonstrated at Whitewater Valley Unit No. 2, a 60-MW coal-fired power plant owned and operated by Richmond Power and Light (RP&L) and located in Richmond, Indiana. The Whitewater plant consumes high-sulfur coals, with sulfur contents ranging from 2.0-2.9 $ZO. The project, co-funded by LIFAC North America and DOE, is being conducted with the participation of Richmond Power and Light, the State of Indiana, the Electric Power Research Institute (EPRI), and the Black Beauty Coal Company. The project has a total cost of $21.4 million and a duration of 48 months from the preliminary design phase through the testing program.« less

Activation of Noble Metals on Metal-Carbide Surfaces: Novel Catalysts for CO Oxidation, Desulfurization and Hydrogenation Reactions

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

Rodriguez J. A.; Illas, F.

2012-01-01

This perspective article focuses on the physical and chemical properties of highly active catalysts for CO oxidation, desulfurization and hydrogenation reactions generated by depositing noble metals on metal-carbide surfaces. To rationalize structure-reactivity relationships for these novel catalysts, well-defined systems are required. High-resolution photoemission, scanning tunneling microscopy (STM) and first-principles periodic density-functional (DF) calculations have been used to study the interaction of metals of Groups 9, 10 and 11 with MC(001) (M = Ti, Zr, V, Mo) surfaces. DF calculations give adsorption energies that range from 2 eV (Cu, Ag, Au) to 6 eV (Co, Rh, Ir). STM images show thatmore » Au, Cu, Ni and Pt grow on the carbide substrates forming two-dimensional islands at very low coverage, and three-dimensional islands at medium and large coverages. In many systems, the results of DF calculations point to the preferential formation of admetal-C bonds with significant electronic perturbations in the admetal. TiC(001) and ZrC(001) transfer some electron density to the admetals facilitating bonding of the adatom with electron-acceptor molecules (CO, O{sub 2}, C{sub 2}H{sub 4}, SO{sub 2}, thiophene, etc.). For example, the Cu/TiC(001) and Au/TiC(001) systems are able to cleave both S-O bonds of SO{sub 2} at a temperature as low as 150 K, displaying a reactivity much larger than that of TiC(001) or extended surfaces of bulk copper and gold. At temperatures below 200 K, Au/TiC is able to dissociate O{sub 2} and perform the 2CO + O{sub 2} {yields} 2CO{sub 2} reaction. Furthermore, in spite of the very poor hydrodesulfurization performance of TiC(001) or Au(111), a Au/TiC(001) surface displays an activity for the hydrodesulfurization of thiophene higher than that of conventional Ni/MoS{sub x} catalysts. In general, the Au/TiC system is more chemically active than systems generated by depositing Au nanoparticles on oxide surfaces. Thus, metal carbides are

Biomolecular hybrid material and process for preparing same and uses for same

DOEpatents

Kim, Jungbae [Richland, WA

2010-11-23

Disclosed is a composition and method for fabricating novel hybrid materials comprised of, e.g., carbon nanotubes (CNTs) and crosslinked enzyme clusters (CECs). In one method, enzyme-CNT hybrids are prepared by precipitation of enzymes which are subsequently crosslinked, yielding crosslinked enzyme clusters (CECs) on the surface of the CNTs. The CEC-enzyme-CNT hybrids exhibit high activity per unit area or mass as well as improved enzyme stability and longevity over hybrid materials known in the art. The CECs in the disclosed materials permit multilayer biocatalytic coatings to be applied to surfaces providing hybrid materials suitable for use in, e.g., biocatalytic applications and devices as described herein.

Flue gas desulfurization gypsum and fly ash

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

Not Available

1992-05-01

The Cumberland Fossil Plant (CUF) is located in Stewart County, Tennessee, and began commercial operation in 1972. This is the Tennessee Valley Authority`s newest fossil (coal-burning) steam electric generating plant. Under current operating conditions, the plant burns approximately seven million tons of coal annually. By-products from the combustion of coal are fly ash, approximately 428,000 tons annually, and bottom ash, approximately 115,000 tons annually. Based on historical load and projected ash production rates, a study was initially undertaken to identify feasible alternatives for marketing, utilization and disposal of ash by-products. The preferred alternative to ensure that facilities are planned formore » all by-products which will potentially be generated at CUF is to plan facilities to handle wet FGD gypsum and dry fly ash. A number of different sites were evaluated for their suitability for development as FGD gypsum and ash storage facilities. LAW Engineering was contracted to conduct onsite explorations of sites to develop information on the general mature of subsurface soil, rock and groundwater conditions in the site areas. Surveys were also conducted on each site to assess the presence of endangered and threatened species, wetlands and floodplains, archaeological and cultural resources, prime farmland and other site characteristics which must be considered from an environmental perspective.« less

40 CFR 63.9991 - What emission limitations, work practice standards, and operating limits must I meet?

Code of Federal Regulations, 2012 CFR

2012-07-01

... Pollutants: Coal- and Oil-Fired Electric Utility Steam Generating Units Emission Limitations and Work... this subpart only if your EGU: (1) Has a system using wet or dry flue gas desulfurization technology... operate the wet or dry flue gas desulfurization technology installed on the unit consistent with § 63...

40 CFR 63.9991 - What emission limitations, work practice standards, and operating limits must I meet?

Code of Federal Regulations, 2013 CFR

2013-07-01

... Pollutants: Coal- and Oil-Fired Electric Utility Steam Generating Units Emission Limitations and Work... this subpart only if your EGU: (1) Has a system using wet or dry flue gas desulfurization technology... operate the wet or dry flue gas desulfurization technology installed on the unit consistent with § 63...

40 CFR 63.9991 - What emission limitations, work practice standards, and operating limits must I meet?

Code of Federal Regulations, 2014 CFR

2014-07-01

... Pollutants: Coal- and Oil-Fired Electric Utility Steam Generating Units Emission Limitations and Work... this subpart only if your EGU: (1) Has a system using wet or dry flue gas desulfurization technology... operate the wet or dry flue gas desulfurization technology installed on the unit consistent with § 63...

Dealing with methionine/homocysteine sulfur: cysteine metabolism to taurine and inorganic sulfur

PubMed Central

Ueki, Iori

2010-01-01

Synthesis of cysteine as a product of the transsulfuration pathway can be viewed as part of methionine or homocysteine degradation, with cysteine being the vehicle for sulfur conversion to end products (sulfate, taurine) that can be excreted in the urine. Transsulfuration is regulated by stimulation of cystathionine β-synthase and inhibition of methylene tetrahydrofolate reductase in response to changes in the level of S-adenosylmethionine, and this promotes homocysteine degradation when methionine availability is high. Cysteine is catabolized by several desulfuration reactions that release sulfur in a reduced oxidation state, generating sulfane sulfur or hydrogen sulfide (H2S), which can be further oxidized to sulfate. Cysteine desulfuration is accomplished by alternate reactions catalyzed by cystathionine β-synthase and cystathionine γ-lyase. Cysteine is also catabolized by pathways that require the initial oxidation of the cysteine thiol by cysteine dioxygenase to form cysteinesulfinate. The oxidative pathway leads to production of taurine and sulfate in a ratio of approximately 2:1. Relative metabolism of cysteine by desulfuration versus oxidative pathways is influenced by cysteine dioxygenase activity, which is low in animals fed low-protein diets and high in animals fed excess sulfur amino acids. Thus, desulfuration reactions dominate when cysteine is deficient, whereas oxidative catabolism dominates when cysteine is in excess. In rats consuming a diet with an adequate level of sulfur amino acids, about two thirds of cysteine catabolism occurs by oxidative pathways and one third by desulfuration pathways. Cysteine dioxygenase is robustly regulated in response to cysteine availability and may function to provide a pathway to siphon cysteine to less toxic metabolites than those produced by cysteine desulfuration reactions. PMID:20162368

Greenidge Multi-Pollutant Control Project

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

Connell, Daniel

2008-10-18

The Greenidge Multi-Pollutant Control Project was conducted as part of the U.S. Department of Energy's Power Plant Improvement Initiative to demonstrate an innovative combination of air pollution control technologies that can cost-effectively reduce emissions of SO{sub 2}, NO{sub x}, Hg, acid gases (SO{sub 3}, HCl, and HF), and particulate matter from smaller coal-fired electric generating units (EGUs). There are about 400 units in the United States with capacities of 50-300 MW that currently are not equipped with selective catalytic reduction (SCR), flue gas desulfurization (FGD), or mercury control systems. Many of these units, which collectively represent more than 55 GWmore » of installed capacity, are difficult to retrofit for deep emission reductions because of space constraints and unfavorable economies of scale, making them increasingly vulnerable to retirement or fuel switching in the face of progressively more stringent environmental regulations. The Greenidge Project sought to confirm the commercial readiness of an emissions control system that is specifically designed to meet the environmental compliance requirements of these smaller coal-fired EGUs by offering a combination of deep emission reductions, low capital costs, small space requirements, applicability to high-sulfur coals, mechanical simplicity, and operational flexibility. The multi-pollutant control system includes a NO{sub x}OUT CASCADE{reg_sign} hybrid selective non-catalytic reduction (SNCR)/in-duct SCR system for NO{sub x} control and a Turbosorp{reg_sign} circulating fluidized bed dry scrubbing system (with a new baghouse) for SO{sub 2}, SO{sub 3}, HCl, HF, and particulate matter control. Mercury removal is provided as a co-benefit of the in-duct SCR, dry scrubber, and baghouse, and by injection of activated carbon upstream of the scrubber, if required. The multi-pollutant control system was installed and tested on the 107-MW{sub e}, 1953-vintage AES Greenidge Unit 4 by a team

Biocatalytic production of D-tagatose: A potential rare sugar with versatile applications.

PubMed

Jayamuthunagai, J; Gautam, P; Srisowmeya, G; Chakravarthy, M

2017-11-02

D-tagatose is a naturally existing rare monosaccharide having prebiotic properties. Minimal absorption, low metabolizing energy, and unique clinical properties are the characteristics of D-tagatose. D-tagatose gained international attention by matching the purpose of alternate sweeteners that is much needed for the control of diabetes among world population. Recent efforts in understanding tagatose bioconversion have generated essential information regarding its production and application. This article reviews the evolution of D-tagatose as an important rare sugar by appreciable improvements in production results and its significant applications resulted of its unique physical, chemical, biological, and clinical properties thus considering it an appropriate product for requisite improvements in technical viability. Based on current knowledge and technology projections, the commercialization of D-tagatose rare sugar as food additive is close to reality.

40 CFR 420.12 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2013 CFR

2013-07-01

... for by-product coke plants which have wet desulfurization systems but only to the extent such systems... limitations, are allowed for by-product coke plants which include indirect ammonia recovery systems but only..., are allowed for by-product coke plants which have wet desulfurization systems but only to the extent...

40 CFR 420.12 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2014 CFR

2014-07-01

... for by-product coke plants which have wet desulfurization systems but only to the extent such systems... limitations, are allowed for by-product coke plants which include indirect ammonia recovery systems but only..., are allowed for by-product coke plants which have wet desulfurization systems but only to the extent...

40 CFR 420.12 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2011 CFR

2011-07-01

... for by-product coke plants which have wet desulfurization systems but only to the extent such systems... limitations, are allowed for by-product coke plants which include indirect ammonia recovery systems but only..., are allowed for by-product coke plants which have wet desulfurization systems but only to the extent...

40 CFR 420.12 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2012 CFR

2012-07-01

... for by-product coke plants which have wet desulfurization systems but only to the extent such systems... limitations, are allowed for by-product coke plants which include indirect ammonia recovery systems but only..., are allowed for by-product coke plants which have wet desulfurization systems but only to the extent...

Functionalization of a membrane sublayer using reverse filtration of enzymes and dopamine coating.

PubMed

Luo, Jianquan; Meyer, Anne S; Mateiu, R V; Kalyani, Dayanand; Pinelo, Manuel

2014-12-24

High permeability, high enzyme loading, and strong antifouling ability are the desired features for a biocatalytic membrane to be used in an enzymatic membrane reactor (EMR). To achieve these goals, the membrane sublayer was enriched with laccase by reverse filtration in this case, and the resulting enzyme-loaded sublayer was covered with a dopamine coating. After membrane reversal, the virgin membrane skin layer was facing the feed and the enzymes were entrapped by a polydopamine network in the membrane sublayer. Thus, the membrane sublayer was functionalized as a catalytically active layer. The effects of the original membrane properties (i.e., materials, pore size, and structure), enzyme type (i.e., laccase and alcohol dehydrogenase), and coating conditions (i.e., time and pH) on the resulting biocatalytic membrane permeability, enzyme loading, and activity were investigated. Using a RC10 kDa membrane with sponge-like sublayer to immobilize laccase with dopamine coating, the trade-off between permeability and enzyme loading was broken, and enzyme loading reached 44.5% without any permeability loss. After 85 days of storage and reuse 14 times, more than 80% of the immobilized laccase activity was retained for the membrane with a dopamine coating, while the relative activity was less than 40% without the coating. The resistance to high temperature and acidic/alkaline pH was also improved by the dopamine coating for the immobilized laccase. Moreover, this biocatalytic membrane could resist mild hydrodynamic cleaning (e.g., back-flushing), but the catalytic ability was reduced by chemical cleaning at extreme pH (e.g., 1.5 and 11.5). Since the immobilized enzyme is not directly facing the bulk of EMRs and the substrate can be specifically selected by the separation skin layer, this biocatalytic membrane is promising for cascade catalytic reactions.

Selective hydrodesulfurization of 4,6-dimethyl-dibenzothiophene in the dominant presence of naphthalene over hybrid CoMo/Al{sub 2}O{sub 3} and Ru/Al{sub 2}O{sub 3} catalysts

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

Isoda, Takaaki; Nagao, Shinichi; Ma, Xiaoliang

1995-12-31

It has been revealed that significant desulfurization of refractory 4-methyldibenzothiophene and 4,6-dimethyldibenzothiophene (4,6-DMDBT) is very essential to achive the low sulfur level of gas oil requested by the current regulation. Their direct desulfurization through the interaction of their sulfur atom with the catalyst surface is sterically hindered by its neighbouring methyl groups. The substrate is found kinetically to be hydrogenated at one of its phenyl rings prior to the desulfurization in order to reduce the steric hindrance through non-planaring configuration (2-4). NiMo / Al{sub 2}O{sub 3} was reported to be superior to CoMo / Al{sub 2}O{sub 3} in the deepmore » desulufurization, because of its higher hydrogenation activity. However, such a hydrogenation route suffers severe inhibition by aromatic species in their dominant presence, because 4,6-DMDBT must compete with the aromatic species to the hydrogenation sites on the catalysts. The aromatic species up to 30 wt % in the gas oil was that completely stop the desulfurization of the particular substrate. The catalyst for the selective hydrogenation of 4,6-DMDBT in the dominant aromatic partners is most wanted to achive its extensive desulfurization in the gas oil, although there have been reported activities of various transition metal sulfides for HDS of dibenzothiophene, and hydrogenation of aromatic hydrocarbons.« less

A MS, SEM-EDX and XRD study of Ti or Cu-doped zinc ferrites as regenerable sorbents for hot coal gas desulfurization

NASA Astrophysics Data System (ADS)

Ahmed, M. A.; García, E.; Alonso, L.; Palacios, J. M.

2000-02-01

Kinetic studies in thermobalance carried out by several authors previously have shown that small concentrations of TiO 2 or CuO can increase substantially the overall sulfidation rate of zinc ferrites, as regenerable sorbents for hot coal gas desulfurization. These oxides modify the textural properties of both the fresh or regenerated and the sulfided sorbent, modifying consequently the sulfidation rate because it is a partially diffusion-controlled process. However, by using grain models it is shown that most of the observed changes are due to changes in the intrinsic reactivity of the sorbent. Detailed studies of characterization in previous papers using different techniques have failed in revealing differential chemical changes that could be associated with a different behavior. In fact, the only significant changes observed in these studies were an apparent disappearance in fresh sorbents calcined at very high temperatures of the Raman effect, and a slight shift of the XPS binding energy of Fe levels, indicating a probable site migration and/or a change of the oxidation state. These characterization results, however, were not completely conclusive and additional efforts should be undertaken. In this paper more sensitive techniques such as Mössbauer spectroscopy (MS), powder X-ray diffraction (XRD) and scanning electron microscopy (SEM-EDX), have been used for the characterization of fresh, regenerated and sulfided sorbents. The study shows that the addition of TiO 2 or CuO induce substantial structural changes in zinc ferrites that can explain their apparent enhancing effect on the overall sulfidation reactivity. Additionally, this effect is decreased as the number of sulfidation-regeneration cycles increases, probably explaining the performance decay exhibited by these sorbents in multicycle tests in a fixed bed reactor.

Coal desulfurization

NASA Technical Reports Server (NTRS)

Corcoran, William H. (Inventor); Vasilakos, Nicholas P. (Inventor); Lawson, Daniel D. (Inventor)

1982-01-01

A method for enhancing solubilizing mass transport of reactive agents into and out of carbonaceous materials, such as coal. Solubility parameters of mass transfer and solvent media are matched to individual peaks in the solubility parameter spectrum of coals to enhance swelling and/or dissolution. Methanol containing reactive agent carriers are found particularly effective for removing organic sulfur from coals by chlorinolysis.

Properties of Controlled Low Strength Material with Circulating Fluidized Bed Combustion Ash and Recycled Aggregates

PubMed Central

Weng, Tsai-Lung; Cheng, An; Chao, Sao-Jeng; Hsu, Hui-Mi

2018-01-01

This study aims to investigate the effect of adding circulating fluidized bed combustion (CFBC) ash, desulfurization slag, air-cooled blast-furnace slag and coal bottom ash to the controlled low-strength material (CLSM). Test methods include slump flow test, ball drop test, water soluble chloride ion content measurement, compressive strength and length change measurement. The results show that (1) the use of CFBC hydration ash with desulfurization slag of slump flow is the best, and the use of CFBC hydration ash with coal bottom ash and slump flow is the worst; (2) CFBC hydration ash with desulfurization slag and chloride ion content is the highest; (3) 24 h ball drop test (diameter ≤ 76 mm), and test results are 70 mm to 76 mm; (4) CFBC hydration ash with desulfurization slag and compression strength is the highest, with the coal bottom ash being the lowest; increase of CFBC hydration ash can reduce compressive strength; and (5) the water-quenched blast furnace slag and CFBC hydration ash would expand, which results in length changes of CLSM specimens. PMID:29724055

Investigation of process variables and intensification effects of ultrasound applied in oxidative desulfurization of model diesel over MoO3/Al2O3 catalyst.

PubMed

Akbari, Azam; Omidkhah, Mohammadreza; Darian, Jafar Towfighi

2014-03-01

A new heterogeneous sonocatalytic system consisting of a MoO3/Al2O3 catalyst and H2O2 combined with ultrasonication was studied to improve and accelerate the oxidation of model sulfur compounds of diesel, resulting in a significant enhancement in the process efficiency. The influence of ultrasound on properties, activity and stability of the catalyst was studied in detail by means of GC-FID, PSD, SEM and BET techniques. Above 98% conversion of DBT in model diesel containing 1000 μg/g sulfur was obtained by new ultrasound-assisted desulfurization at H2O2/sulfur molar ratio of 3, temperature of 318 K and catalyst dosage of 30 g/L after 30 min reaction, contrary to the 55% conversion obtained during the silent process. This improvement was considerably affected by operation parameters and catalyst properties. The effects of main process variables were investigated using response surface methodology in silent process compared to ultrasonication. Ultrasound provided a good dispersion of catalyst and oxidant by breakage of hydrogen bonding and deagglomeration of them in the oil phase. Deposition of impurities on the catalyst surface caused a quick deactivation in silent experiments resulting only 5% of DBT oxidation after 6 cycles of silent reaction by recycled catalyst. Above 95% of DBT was oxidized after 6 ultrasound-assisted cycles showing a great improvement in stability by cleaning the surface during ultrasonication. A considerable particle size reduction was also observed after 3 h sonication that could provide more dispersion of catalyst in model fuel.