Science.gov

Sample records for synthesis gas

  1. Gas Phase Nanoparticle Synthesis

    NASA Astrophysics Data System (ADS)

    Granqvist, Claes; Kish, Laszlo; Marlow, William

    This book deals with gas-phase nanoparticle synthesis and is intended for researchers and research students in nanomaterials science and engineering, condensed matter physics and chemistry, and aerosol science. Gas-phase nanoparticle synthesis is instrumental to nanotechnology - a field in current focus that raises hopes for environmentally benign, resource-lean manufacturing. Nanoparticles can be produced by many physical, chemical, and even biological routes. Gas-phase synthesis is particularly interesting since one can achieve accurate manufacturing control and hence industrial viability.

  2. Preparation of ammonia synthesis gas

    SciTech Connect

    Shires, P.J.; van Dijk, C.P.; Cassata, J.R.; Mandelik, B.G.

    1984-10-30

    Ammonia synthesis gas having excess nitrogen is produced in a reactor-exchanger primary reformer followed by an autothermal secondary reformer wherein process air for the latter is preheated by heat exchange with gas turbine exhaust and the primary reformer is heated by synthesis gas from the secondary reformer.

  3. Synthesis Gas Biorefinery.

    PubMed

    Dahmen, N; Henrich, E; Henrich, T

    2017-03-23

    Synthesis gas or syngas is an intermediate, which can be produced by gasification from a variety of carbonaceous feedstocks including biomass. Carbon monoxide and hydrogen, the main constituents of syngas, can be subjected to a broad range of chemical and microbial synthesis processes, leading to gaseous and liquid hydrocarbon fuels as well as to platform and fine chemicals. Gasification of solid biomass differs from coal gasification by chemical composition, heating value, ash behavior, and other technical and biomass related issues. By thermochemical pre-treatment of lignocellulose as the most abundant form of biomass, for example, by torrefaction or fast pyrolysis, energy dense fuels for gasification can be obtained, which can be used in the different types of gasifiers available today. A number of pilot and demonstration plants exist, giving evidence of the broad technology portfolio developed so far. Therefore, a syngas biorefinery is highly flexible in regard to feedstock and product options. However, the technology is complex and does not result in competitive production costs today. Added value can be generated by suitable integration of thermochemical, biochemical, and chemical processes.

  4. Oxygenates vs. synthesis gas

    SciTech Connect

    Kamil Klier; Richard G. Herman; Alessandra Beretta; Maria A. Burcham; Qun Sun; Yeping Cai; Biswanath Roy

    1999-04-01

    Methanol synthesis from H{sub 2}/CO has been carried out at 7.6 MPa over zirconia-supported copper catalysts. Catalysts with nominal compositions of 10/90 mol% and 30/70 mol% Cu/ZrO{sub 2} were used in this study. Additionally, a 3 mol% cesium-doped 10/90 catalyst was prepared to study the effect of doping with heavy alkali, and this promoter greatly increased the methanol productivity. The effects of CO{sub 2} addition, water injection, reaction temperature, and H{sub 2}/C0 ratio have been investigated. Both CO{sub 2} addition to the synthesis gas and cesium doping of the catalyst promoted methanol synthesis, while inhibiting the synthesis of dimethyl ether. Injection of water, however, was found to slightly suppress methanol and dimethyl ether formation while being converted to CO{sub 2} via the water gas shift reaction over these catalysts. There was no clear correlation between copper surface area and catalyst activity. Surface analysis of the tested samples revealed that copper tended to migrate and enrich the catalyst surface. The concept of employing a double-bed reactor with a pronounced temperature gradient to enhance higher alcohol synthesis was explored, and it was found that utilization of a Cs-promoted Cu/ZnO/Cr{sub 2}O{sub 3} catalyst as a first lower temperature bed and a Cs-promoted ZnO/Cr{sub 2}O{sub 3} catalyst as a second high-temperature bed significantly promoted the productivity of 2-methyl-1-propanol (isobutanol) from H{sub 2}/CO synthesis gas mixtures. While the conversion of CO to C{sub 2+} oxygenates over the double-bed configuration was comparable to that observed over the single Cu-based catalyst, major changes in the product distribution occurred by the coupling to the zinc chromite catalyst; that is, the productivity of the C{sub 1}-C{sub 3} alcohols decreased dramatically, and 2-methyl branched alcohols were selectively formed. The desirable methanol/2-methyl oxygenate molar ratios close to 1 were obtained in the present double

  5. Synthesis gas method and apparatus

    DOEpatents

    Kelly, Sean M.; Kromer, Brian R.; Litwin, Michael M.; Rosen, Lee J.; Christie, Gervase Maxwell; Wilson, Jamie; Kosowski, Lawrence W; Robinson, Charles

    2015-11-06

    A method and apparatus for producing a synthesis gas product having one or more oxygen transport membrane elements thermally coupled to one or more catalytic reactors such that heat generated from the oxygen transport membrane element supplies endothermic heating requirements for steam methane reforming reactions occurring within the catalytic reactor through radiation and convention heat transfer. A hydrogen containing stream containing no more than 20 percent methane is combusted within the oxygen transport membrane element to produce the heat and a heated combustion product stream. The heated combustion product stream is combined with a reactant stream to form a combined stream that is subjected to the reforming within the catalytic reactor. The apparatus may include modules in which tubular membrane elements surround a central reactor tube.

  6. Synthesis gas method and apparatus

    DOEpatents

    Kelly, Sean M.; Kromer, Brian R.; Litwin, Michael M.; Rosen, Lee J.; Christie, Gervase Maxwell; Wilson, Jamie R.; Kosowski, Lawrence W.; Robinson, Charles

    2013-01-08

    A method and apparatus for producing a synthesis gas product having one or more oxygen transport membrane elements thermally coupled to one or more catalytic reactors such that heat generated from the oxygen transport membrane element supplies endothermic heating requirements for steam methane reforming reactions occurring within the catalytic reactor through radiation and convention heat transfer. A hydrogen containing stream containing no more than 20 percent methane is combusted within the oxygen transport membrane element to produce the heat and a heated combustion product stream. The heated combustion product stream is combined with a reactant stream to form a combined stream that is subjected to the reforming within the catalytic reactor. The apparatus may include modules in which tubular membrane elements surround a central reactor tube.

  7. High pressure synthesis gas fermentation

    SciTech Connect

    Not Available

    1991-01-01

    The purpose of this research project is to build and test a pressure fermentation system for the production of ethanol from synthesis gas. The fermenters, pumps, controls, and analytical system will be procured or fabricated and assembled in our laboratory. This system will then be used to determine the effects of high pressure on growth and ethanol production by clostridium ljungdahlii. The limits of cell concentration and mass transport relationships will be found in continuous stirred tank reactor and immobilized cell reactors. The minimum retention times and reactor volumes will be found for ethanol production in these reactors. Retention times of a few seconds are expected to result from these experiments. 2 figs., 2 tabs.

  8. Biological conversion of synthesis gas culture development

    SciTech Connect

    Klasson, K.T.; Basu, R.; Johnson, E.R.; Clausen, E.C.; Gaddy, J.L.

    1992-03-01

    Research continues on the conversion of synthesis by shift reactions involving bacteria. Topics discussed here include: biological water gas shift, sulfur gas utilization, experimental screening procedures, water gas shift studies, H{sub 2}S removal studies, COS degradation by selected CO-utilizing bacteria, and indirect COS utilization by Chlorobia. (VC)

  9. ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS

    SciTech Connect

    Unknown

    1999-04-01

    The overall objectives of this program are to investigate potential technologies for the conversion of synthesis gas to oxygenated and hydrocarbon fuels and industrial chemicals, and to demonstrate the most promising technologies at DOE's LaPorte, Texas, Slurry Phase Alternative Fuels Development Unit (AFDU). The program will involve a continuation of the work performed under the Alternative Fuels from Coal-Derived Synthesis Gas Program and will draw upon information and technologies generated in parallel current and future DOE-funded contracts.

  10. Alternative fuels and chemicals from synthesis gas

    SciTech Connect

    Unknown

    1998-08-01

    The overall objectives of this program are to investigate potential technologies for the conversion of synthesis gas to oxygenated and hydrocarbon fuels and industrial chemicals, and to demonstrate the most promising technologies at DOE's LaPorte, Texas, Slurry Phase Alternative Fuels Development Unit (AFDU). The program will involve a continuation of the work performed under the Alternative Fuels from Coal-Derived Synthesis Gas Program and will draw upon information and technologies generated in parallel current and future DOE-funded contracts.

  11. Process for producing synthesis gas from wood

    SciTech Connect

    Curran, G.P.; Lancet, M.S.

    1982-06-15

    In a process for producing synthesis gas by reacting a solid carbonaceous fuel with water in the presence of a carbon dioxide acceptor to produce a synthesis gas rich in hydrogen with at least a portion of the carbon dioxide so produced being reacted with the carbon dioxide acceptor to produce calcium carbonate and to provide sufficient heat to maintain a desired reaction temperature, an improvement comprising; the use of finely-divided wood as the solid carbonaceous fuel.

  12. Alternative Fuels and Chemicals from Synthesis Gas

    SciTech Connect

    Peter Tijrn

    2003-01-02

    The overall objectives of this program are to investigate potential technologies for the conversion of synthesis gas to oxygenated and hydrocarbon fuels and industrial chemicals, and to demonstrate the most promising technologies at DOE's LaPorte, Texas, Slurry Phase Alternative Fuels Development Unit (AFDU). The program will involve a continuation of the work performed under the Alternative Fuels from Coal-Derived Synthesis Gas Program and will draw upon information and technologies generated in parallel current and future DOE-funded contracts.

  13. ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS

    SciTech Connect

    Unknown

    1999-01-01

    The overall objectives of this program are to investigate potential technologies for the conversion of synthesis gas to oxygenated and hydrocarbon fuels and industrial chemicals, and to demonstrate the most promising technologies at DOE's LaPorte, Texas, Slurry Phase Alternative Fuels Development Unit (AFDU). The program will involve a continuation of the work performed under the Alternative Fuels from Coal-Derived Synthesis Gas Program and will draw upon information and technologies generated in parallel current and future DOE-funded contracts.

  14. ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS

    SciTech Connect

    Unknown

    1998-01-01

    The overall objectives of this program are to investigate potential technologies for the conversion of synthesis gas to oxygenated and hydrocarbon fuels and industrial chemicals, and to demonstrate the most promising technologies at DOE's LaPorte, Texas, Slurry Phase Alternative Fuels Development Unit (AFDU). The program will involve a continuation of the work performed under the Alternative Fuels from Coal-Derived Synthesis Gas Program and will draw upon information and technologies generated in parallel current and future DOE-funded contracts.

  15. OPTIMIZING SYNTHESIS GAS YIELD FROM THE CROSS ...

    EPA Pesticide Factsheets

    Symposium Paper Biomass can be gasified to yield synthesis gas, tars, and ash. The process is governed by a number of parameters such as the temperature of the gasifying medium (in this case), and the moisture content of the feedstock. Synthesis gas from gasifying wood pellets was collected and analyzed as a function of inlet air temperature and feedstock moisture content. The air was introduced at temperatures ranging from 630 to 730 °C and the moisture content of the feedstock ranged from 8 to 20%. The data collected was used to establish the relationship between the outcome of gasification and these two parameters, and then to determine optimal operating parameters for maximizing the fuel value (maximizing the concentrations of flammable gases in the synthesis gas) while minimizing the production of gasification tars.

  16. High pressure synthesis gas fermentation

    SciTech Connect

    Not Available

    1991-01-01

    Construction of the high pressure gas phase fermentation system is nearing completion. All non-explosion proof components will be housed separately in a gas-monitored plexiglas cabinet. A gas-monitoring system has been designed to ensure the safety of the operations in case of small or large accidental gas releases. Preliminary experiments investigating the effects of high pressure on Clostridium 1jungdahlii have shown that growth and CO uptake are not negatively affected and CO uptake by an increased total pressure of 100 psig at a syngas partial pressure of 10 psig.

  17. High pressure synthesis gas fermentation

    SciTech Connect

    Not Available

    1992-01-01

    The construction of the high pressure gas phase fermentation system has been completed. Photographs of the various components of the system are presented, along with an operating procedure for the equipment.

  18. Process for production desulfurized of synthesis gas

    DOEpatents

    Wolfenbarger, James K.; Najjar, Mitri S.

    1993-01-01

    A process for the partial oxidation of a sulfur- and silicate-containing carbonaceous fuel to produce a synthesis gas with reduced sulfur content which comprises partially oxidizing said fuel at a temperature in the range of 1900.degree.-2600.degree. F. in the presence of a temperature moderator, an oxygen-containing gas and a sulfur capture additive which comprises a calcium-containing compound portion, a sodium-containing compound portion, and a fluoride-containing compound portion to produce a synthesis gas comprising H.sub.2 and CO with a reduced sulfur content and a molten slag which comprises (1) a sulfur-containing sodium-calcium-fluoride silicate phase; and (2) a sodium-calcium sulfide phase.

  19. Numerical simulation of synthesis gas incineration

    NASA Astrophysics Data System (ADS)

    Kazakov, A. V.; Khaustov, S. A.; Tabakaev, R. B.; Belousova, Y. A.

    2016-04-01

    The authors have analysed the expediency of the suggested low-grade fuels application method. Thermal processing of solid raw materials in the gaseous fuel, called synthesis gas, is investigated. The technical challenges concerning the applicability of the existing gas equipment developed and extensively tested exclusively for natural gas were considered. For this purpose computer simulation of three-dimensional syngas-incinerating flame dynamics was performed by means of the ANSYS Multiphysics engineering software. The subjects of studying were: a three-dimensional aerodynamic flame structure, heat-release and temperature fields, a set of combustion properties: a flare range and the concentration distribution of burnout reagents. The obtained results were presented in the form of a time-averaged pathlines with color indexing. The obtained results can be used for qualitative and quantitative evaluation of complex multicomponent gas incineration singularities.

  20. Biological conversion of synthesis gas

    SciTech Connect

    Ackerson, M.D.; Clausen, E.C.; Gaddy, J.L.

    1993-01-05

    Syngas is known to contain approximately 1 percent H[sub 2]S, along with CO[sub 2], C0[sub 2], H[sub 2] and CH[sub 4]. Similarly, the syngas may become contaminated with oxygen, particularly during reactor start-up and during maintenance. Previous studies with the water-gas shift bacterium Rhodospirillum rubrum have shown that the bacterium is tolerant of small quantities of oxygen, but the effects of oxygen on CO-consumption are unknown. Similarly, R. rubrum is known to be tolerant of H[sub 2]S, with high concentrations of H[sub 2]S negatively affecting CO-uptake. Batch experiments were thus carried out to determine the effects of H[sub 2]S and O[sub 2] on CO-uptake by R. rubrum. The results of these experiments were quantified by using Monod equations modified by adding terms for CO, H[sub 2]S and O[sub 2] inhibition. The techniques used in determining kinetic expressions previously shown for other gas-phase substrate bacterial systems including R. rubrum were utilized.

  1. Method and apparatus for producing synthesis gas

    DOEpatents

    Hemmings, John William; Bonnell, Leo; Robinson, Earl T.

    2010-03-03

    A method and apparatus for reacting a hydrocarbon containing feed stream by steam methane reforming reactions to form a synthesis gas. The hydrocarbon containing feed is reacted within a reactor having stages in which the final stage from which a synthesis gas is discharged incorporates expensive high temperature materials such as oxide dispersed strengthened metals while upstream stages operate at a lower temperature allowing the use of more conventional high temperature alloys. Each of the reactor stages incorporate reactor elements having one or more separation zones to separate oxygen from an oxygen containing feed to support combustion of a fuel within adjacent combustion zones, thereby to generate heat to support the endothermic steam methane reforming reactions.

  2. Biological conversion of synthesis gas

    SciTech Connect

    Klasson, K.T.; Basu, R.; Johnson, E.R.; Clausen, E.C.; Gaddy, J.L.

    1992-03-01

    Mass transfer and kinetic studies were carried out for the Rhodospirillum rubrum and Chlorobium thiosulfatophilum bacterial systems. R. rubrum is a photosynthetic anaerobic bacterium which catalyzes the biological water gas shift reaction: CO + H[sub 2]0 [yields] CO[sub 2] + H[sub 2]. C. thiosulfatophilum is also a H[sub 2]S and COS to elemental sulfur. The growth of R. rubrum may be satisfactorily carried out at 25[degree] and 30[degree]C, while CO uptake and thus the conversion of CO best occurs at temperatures of either 30[degree], 32[degree] or 34[degree]C. The rate of conversion of COs and H[sub 2]O to CO[sub 2] and H[sub 2]S may be modeled by a first order rate expression. The rate constant at 30[degree]C was found to be 0.243 h[sup [minus]1]. The growth of C. thiosulfatophilum may be modeled in terms of incoming light intensity using a Monod equation: [mu] = [sub 351] + I[sub o]/[sup 0.152]I[sub o]. Comparisons of the growth of R. rubrum and C. thiosulfatophilum shows that the specific growth rate of C. thiosulfatophilum is much higher at a given light intensity.

  3. High octane ethers from synthesis gas-derived alcohols

    SciTech Connect

    Klier, K.; Herman, R.G.; Johansson, M.; Feeley, O.C.

    1992-01-01

    The objective of the proposed research is to synthesize high octane ethers, primarily methyl isobutyl ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from H{sub 2}/CO/CO{sub 2} coal-derived synthesis gas via alcohol mixtures that are rich in methanol and 2-methyl-1-propanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers.

  4. Process for producing dimethyl ether form synthesis gas

    DOEpatents

    Pierantozzi, Ronald

    1985-01-01

    This invention pertains to a Fischer Tropsch process for converting synthesis gas to an oxygenated hydrocarbon with particular emphasis on dimethyl ether. Synthesis gas comprising carbon monoxide and hydrogen are converted to dimethyl ether by carrying out the reaction in the presence of an alkali metal-manganese-iron carbonyl cluster incorporated onto a zirconia-alumina support.

  5. Process for producing dimethyl ether from synthesis gas

    DOEpatents

    Pierantozzi, R.

    1985-06-04

    This invention pertains to a Fischer Tropsch process for converting synthesis gas to an oxygenated hydrocarbon with particular emphasis on dimethyl ether. Synthesis gas comprising carbon monoxide and hydrogen are converted to dimethyl ether by carrying out the reaction in the presence of an alkali metal-manganese-iron carbonyl cluster incorporated onto a zirconia-alumina support.

  6. High pressure synthesis gas conversion. Final report

    SciTech Connect

    Not Available

    1993-05-01

    The purpose of this research project is to build and test a high pressure fermentation system for the production of ethanol from synthesis gas. The fermenters, pumps, controls, and analytical system were procured or fabricated and assembled in our laboratory. This system was then used to determine the effects of high pressure on growth and ethanol production by Clostridium ljungdahlii. The limits of cell concentration and mass transport relationships were found in CSTR and immobilized cell reactors (ICR). The minimum retention times and reactor volumes were found for ethanol production in these reactors. A maximum operating pressure of 150 psig has been shown to be possible for C. ljungdahlli with the medium of Phillips et al. This medium was developed for atmospheric pressure operation in the CSTR to yield maximum ethanol concentrations and thus is not best for operation at elevated pressures. It is recommended that a medium development study be performed for C. ljungdahlii at increased pressure. Cell concentration, gas conversion and product concentration profiles were presented for C. ljungdahlii as a function of gas flow rate, the variable which affects bacterium performance the most. This pressure was chosen as a representative pressure over the 0--150 psig operating pressure range for the bacterium. Increased pressure negatively affected ethanol productivity probably due to the fact that medium composition was designed for atmospheric pressure operation. Medium development at increased pressure is necessary for high pressure development of the system.

  7. Alternative fuels and chemicals from synthesis gas

    SciTech Connect

    Unknown

    1998-12-01

    A DOE/PETC funded study was conducted to examine the use of a liquid phase mixed alcohol synthesis (LPMAS) plant to produce gasoline blending ethers. The LPMAS plant was integrated into three utilization scenarios: a coal fed IGCC power plant, a petroleum refinery using coke as a gasification feedstock, and a standalone natural gas fed partial oxidation plant. The objective of the study was to establish targets for the development of catalysts for the LPMAS reaction. In the IGCC scenario, syngas conversions need only be moderate because unconverted syngas is utilized by the combined cycle system. A once through LPMAS plant achieving syngas conversions in the range of 38--49% was found to be suitable. At a gas hourly space velocity of 5,000 sL/Kg-hr and a methanol:isobutanol selectivity ratio of 1.03, the target catalyst productivity ranges from 370 to 460 g iBuOH/Kg-hr. In the petroleum refinery scenario, high conversions ({approximately}95%) are required to avoid overloading the refinery fuel system with low Btu content unconverted syngas. To achieve these high conversions with the low H{sub 2}/CO ratio syngas, a recycle system was required (because of the limit imposed by methanol equilibrium), steam was injected into the LPMAS reactor, and CO{sub 2} was removed from the recycle loop. At the most economical recycle ratio, the target catalyst productivity is 265 g iBuOH/Kg-hr. In the standalone LPMAS scenario, essentially complete conversions are required to achieve a fuel balanced plant. At the most economical recycle ratio, the target catalyst productivity is 285 g iBuOH/Kg-hr. The economics of this scenario are highly dependent on the cost of the natural gas feedstock and the location of the plant. For all three case scenarios, the economics of a LPMAS plant is marginal at current ether market prices. Large improvements over demonstrated catalyst productivity and alcohol selectivity are required.

  8. Autothermal Reforming of Natural Gas to Synthesis Gas

    SciTech Connect

    Steven F. Rice; David P. Mann

    2007-04-13

    This Project Final Report serves to document the project structure and technical results achieved during the 3-year project titled Advanced Autothermal Reformer for US Dept of Energy Office of Industrial Technology. The project was initiated in December 2001 and was completed March 2005. It was a joint effort between Sandia National Laboratories (Livermore, CA), Kellogg Brown & Root LLC (KBR) (Houston, TX) and Süd-Chemie (Louisville, KY). The purpose of the project was to develop an experimental capability that could be used to examine the propensity for soot production in an Autothermal Reformer (ATR) during the production of hydrogen-carbon monoxide synthesis gas intended for Gas-to-Liquids (GTL) applications including ammonia, methanol, and higher hydrocarbons. The project consisted of an initial phase that was focused on developing a laboratory-scale ATR capable of reproducing conditions very similar to a plant scale unit. Due to budget constraints this effort was stopped at the advanced design stages, yielding a careful and detailed design for such a system including ATR vessel design, design of ancillary feed and let down units as well as a PI&D for laboratory installation. The experimental effort was then focused on a series of measurements to evaluate rich, high-pressure burner behavior at pressures as high as 500 psi. The soot formation measurements were based on laser attenuation at a view port downstream of the burner. The results of these experiments and accompanying calculations show that soot formation is primarily dependent on oxidation stoichiometry. However, steam to carbon ratio was found to impact soot production as well as burner stability. The data also showed that raising the operating pressure while holding mass flow rates constant results in considerable soot formation at desirable feed ratios. Elementary reaction modeling designed to illuminate the role of CO2 in the burner feed showed that the conditions in the burner allow for the direct

  9. Evaluation of Reformer Produced Synthesis Gas for Emissions Reductions in Natural Gas Reciprocating Engines

    SciTech Connect

    Mark V. Scotto; Mark A. Perna

    2010-05-30

    Rolls-Royce Fuel Cell Systems (US) Inc. (RRFCS) has developed a system that produces synthesis gas from air and natural gas. A near-term application being considered for this technology is synthesis gas injection into reciprocating engines for reducing NOx emissions. A proof of concept study using bottled synthesis gas and a two-stroke reciprocating engine showed that injecting small amounts of highflammables content synthesis gas significantly improved combustion stability and enabled leaner engine operation resulting in over 44% reduction in NOx emissions. The actual NOx reduction that could be achieved in the field is expected to be engine specific, and in many cases may be even greater. RRFCS demonstrated that its synthesis gas generator could produce synthesis gas with the flammables content that was successfully used in the engine testing. An economic analysis of the synthesis gas approach estimates that its initial capital cost and yearly operating cost are less than half that of a competing NOx reduction technology, Selective Catalytic Reduction. The next step in developing the technology is an integrated test of the synthesis gas generator with an engine to obtain reliability data for system components and to confirm operating cost. RRFCS is actively pursuing opportunities to perform the integrated test. A successful integrated test would demonstrate the technology as a low-cost option to reduce NOx emissions from approximately 6,000 existing two-stroke, natural gas-fired reciprocating engines used on natural gas pipelines in North America. NOx emissions reduction made possible at a reasonable price by this synthesis gas technology, if implemented on 25% of these engines, would be on the order of 25,000 tons/year.

  10. Evaluation of Reformer Produced Synthesis Gas for Emissions Reductions in Natural Gas Reciprocating Engines

    SciTech Connect

    Mark Scotto

    2010-05-30

    Rolls-Royce Fuel Cell Systems (US) Inc. (RRFCS) has developed a system that produces synthesis gas from air and natural gas. A near-term application being considered for this technology is synthesis gas injection into reciprocating engines for reducing NO{sub x} emissions. A proof of concept study using bottled synthesis gas and a two-stroke reciprocating engine showed that injecting small amounts of high-flammable content synthesis gas significantly improved combustion stability and enabled leaner engine operation resulting in over 44% reduction in NO{sub x} emissions. The actual NO{sub x} reduction that could be achieved in the field is expected to be engine specific, and in many cases may be even greater. RRFCS demonstrated that its synthesis gas generator could produce synthesis gas with the flammable content that was successfully used in the engine testing. An economic analysis of the synthesis gas approach estimates that its initial capital cost and yearly operating cost are less than half that of a competing NO{sub x} reduction technology, Selective Catalytic Reduction. The next step in developing the technology is an integrated test of the synthesis gas generator with an engine to obtain reliability data for system components and to confirm operating cost. RRFCS is actively pursuing opportunities to perform the integrated test. A successful integrated test would demonstrate the technology as a low-cost option to reduce NO{sub x} emissions from approximately 6,000 existing two-stroke, natural gas-fired reciprocating engines used on natural gas pipelines in North America. NO{sub x} emissions reduction made possible at a reasonable price by this synthesis gas technology, if implemented on 25% of these engines, would be on the order of 25,000 tons/year.

  11. Alternative fuel and chemicals from synthesis gas

    SciTech Connect

    1996-05-01

    Development of a reliable and cost-effective method of wax/catalyst separation is a key step toward a commercially viable slurry reactor process with iron oxide-based catalyst for Fischer-Tropsch (F-T) synthesis of hydrocarbon transportation fuels. Although a variety of suitable catalysts (including, for example, cobalt-based catalysts) are available, iron oxide-based catalysts are preferred for coal-derived, CO-rich syngas because, in addition to catalyzing the F-T reaction, they simultaneously catalyze the reaction stifling CO to H{sub 2}, obviating a separate shift process block and associated costs. Because of the importance of development of this wax/catalyst separation, a study was initiated in February 1991. P. Z. Zhou of Burns and Roe reviewed the status of F-T wax/catalyst separation techniques. This led to the selection of a filtration system for the separation. Pilot tests were conducted by Mott Porous Metal Products in 1992 to develop this system. Initial results were good, but problems were encountered in follow-up testing. As a result of the testing, a filter was selected for use on the pilot plant. In LaPorte, Texas, APCI has been operating a pilot plant for the development of various synthesis gas technologies with DOE and industry support. The APCI F-T program builds on the DOE-sponsored laboratory-scale work by Mobil, reported in the mid-1980s, which used an iron oxide catalyst to produce high-quality F-T liquids in relatively compact reactors. Separation of the catalyst solids from the wax still represents a challenge. In the summer of 1992, testing of the selected filter was begun as part of the pilot plant testing. The filter performed poorly. Separation of the catalyst was primarily by sedimentation. It was recommended that the wax/catalyst separation be developed further.

  12. Integrated production of fuel gas and oxygenated organic compounds from synthesis gas

    DOEpatents

    Moore, Robert B.; Hegarty, William P.; Studer, David W.; Tirados, Edward J.

    1995-01-01

    An oxygenated organic liquid product and a fuel gas are produced from a portion of synthesis gas comprising hydrogen, carbon monoxide, carbon dioxide, and sulfur-containing compounds in a integrated feed treatment and catalytic reaction system. To prevent catalyst poisoning, the sulfur-containing compounds in the reactor feed are absorbed in a liquid comprising the reactor product, and the resulting sulfur-containing liquid is regenerated by stripping with untreated synthesis gas from the reactor. Stripping offgas is combined with the remaining synthesis gas to provide a fuel gas product. A portion of the regenerated liquid is used as makeup to the absorber and the remainder is withdrawn as a liquid product. The method is particularly useful for integration with a combined cycle coal gasification system utilizing a gas turbine for electric power generation.

  13. Solid fuel volatilization to produce synthesis gas

    DOEpatents

    Schmidt, Lanny D.; Dauenhauer, Paul J.; Degenstein, Nick J.; Dreyer, Brandon J.; Colby, Joshua L.

    2014-07-29

    A method comprising contacting a carbon and hydrogen-containing solid fuel and a metal-based catalyst in the presence of oxygen to produce hydrogen gas and carbon monoxide gas, wherein the contacting occurs at a temperature sufficiently high to prevent char formation in an amount capable of stopping production of the hydrogen gas and the carbon monoxide gas is provided. In one embodiment, the metal-based catalyst comprises a rhodium-cerium catalyst. Embodiments further include a system for producing syngas. The systems and methods described herein provide shorter residence time and high selectivity for hydrogen and carbon monoxide.

  14. Activation of catalysts for synthesizing methanol from synthesis gas

    DOEpatents

    Blum, David B.; Gelbein, Abraham P.

    1985-01-01

    A method for activating a methanol synthesis catalyst is disclosed. In this method, the catalyst is slurried in an inert liquid and is activated by a reducing gas stream. The activation step occurs in-situ. That is, it is conducted in the same reactor as is the subsequent step of synthesizing methanol from a methanol gas stream catalyzed by the activated catalyst still dispersed in a slurry.

  15. Synthesis and deposition of metal nanoparticles by gas condensation process

    SciTech Connect

    Maicu, Marina Glöß, Daniel; Frach, Peter; Schmittgens, Ralph; Gerlach, Gerald; Hecker, Dominic

    2014-03-15

    In this work, the synthesis of Pt and Ag nanoparticles by means of the inert gas phase condensation of sputtered atomic vapor is presented. The process parameters (power, sputtering time, and gas flow) were varied in order to study the relationship between deposition conditions and properties of the nanoparticles such as their quantity, size, and size distribution. Moreover, the gas phase condensation process can be combined with a plasma enhanced chemical vapor deposition procedure in order to deposit nanocomposite coatings consisting of metallic nanoparticles embedded in a thin film matrix material. Selected examples of application of the generated nanoparticles and nanocomposites are discussed.

  16. Scale study of direct synthesis of dimethyl ether from biomass synthesis gas.

    PubMed

    Lv, Yongxing; Wang, Tiejun; Wu, Chuangzhi; Ma, Longlong; Zhou, Yi

    2009-01-01

    We investigated the synthesis of dimethyl ether (DME) from biomass synthesis gas using a kind of hybrid catalyst consisting of methanol and HZSM-5 zeolite in a fixed-bed reactor in a 100 ton/year pilot plant. The biomass synthesis gas was produced by oxygen-rich gasification of corn core in a two-stage fixed bed. The results showed that CO conversions reached 82.00% and 73.55%, the selectivities for DME were 73.95% and 69.73%, and the space-time yields were 124.28 kg m(-3) h(-1) and 203.80 kg m(-3) h(-1) when gas hourly space velocities were 650 h(-1) and 1200 h(-1), respectively. Deoxidation and tar removal from biomass synthesis gas was critical to the stable operation of the DME synthesis system. Using single-pass synthesis, the H(2)/CO ratio improved from 0.98-1.17 to 2.12-2.22. The yield of DME would be increased greatly if the exhaust was reused after removal of the CO(2).

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

    DOEpatents

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

    2000-01-01

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

  18. Process for production of synthesis gas with reduced sulfur content

    DOEpatents

    Najjar, Mitri S.; Corbeels, Roger J.; Kokturk, Uygur

    1989-01-01

    A process for the partial oxidation of a sulfur- and silicate-containing carbonaceous fuel to produce a synthesis gas with reduced sulfur content which comprises partially oxidizing said fuel at a temperature in the range of 1800.degree.-2200.degree. F. in the presence of a temperature moderator, an oxygen-containing gas and a sulfur capture additive which comprises an iron-containing compound portion and a sodium-containing compound portion to produce a synthesis gas comprising H.sub.2 and CO with a reduced sulfur content and a molten slag which comprises (i) a sulfur-containing sodium-iron silicate phase and (ii) a sodium-iron sulfide phase. The sulfur capture additive may optionally comprise a copper-containing compound portion.

  19. Gas extrusion in natural products total synthesis.

    PubMed

    Jiang, Xuefeng; Shi, Lei; Liu, Hui; Khan, Akbar H; Chen, Jason S

    2012-11-14

    The thermodynamic driving force from the release of a gaseous molecule drives a broad range of synthetic transformations. This review focuses on gas expulsion in key reactions within natural products total syntheses, selected from the past two decades. The highlighted examples survey transformations that generate sulfur dioxide, carbon dioxide, carbonyl sulfide, or nitrogen through polar, radical, pericyclic, photochemical, or organometallic mechanisms. Of particular interest are applications wherein the gas extrusion enables formation of a synthetically challenging motif, such as an unusually hindered or strained bond.

  20. NOVEL REACTOR FOR THE PRODUCTION OF SYNTHESIS GAS

    SciTech Connect

    Vasilis Papavassiliou; Leo Bonnell; Dion Vlachos

    2004-12-01

    Praxair investigated an advanced technology for producing synthesis gas from natural gas and oxygen This production process combined the use of a short-reaction time catalyst with Praxair's gas mixing technology to provide a novel reactor system. The program achieved all of the milestones contained in the development plan for Phase I. We were able to develop a reactor configuration that was able to operate at high pressures (up to 19atm). This new reactor technology was used as the basis for a new process for the conversion of natural gas to liquid products (Gas to Liquids or GTL). Economic analysis indicated that the new process could provide a 8-10% cost advantage over conventional technology. The economic prediction although favorable was not encouraging enough for a high risk program like this. Praxair decided to terminate development.

  1. Production of biofuels from synthesis gas using microbial catalysts.

    PubMed

    Tirado-Acevedo, Oscar; Chinn, Mari S; Grunden, Amy M

    2010-01-01

    World energy consumption is expected to increase 44% in the next 20 years. Today, the main sources of energy are oil, coal, and natural gas, all fossil fuels. These fuels are unsustainable and contribute to environmental pollution. Biofuels are a promising source of sustainable energy. Feedstocks for biofuels used today such as grain starch are expensive and compete with food markets. Lignocellulosic biomass is abundant and readily available from a variety of sources, for example, energy crops and agricultural/industrial waste. Conversion of these materials to biofuels by microorganisms through direct hydrolysis and fermentation can be challenging. Alternatively, biomass can be converted to synthesis gas through gasification and transformed to fuels using chemical catalysts. Chemical conversion of synthesis gas components can be expensive and highly susceptible to catalyst poisoning, limiting biofuel yields. However, there are microorganisms that can convert the CO, H(2), and CO(2) in synthesis gas to fuels such as ethanol, butanol, and hydrogen. Biomass gasification-biosynthesis processing systems have shown promise as some companies have already been exploiting capable organisms for commercial purposes. The discovery of novel organisms capable of higher product yield, as well as metabolic engineering of existing microbial catalysts, makes this technology a viable option for reducing our dependency on fossil fuels.

  2. Biological conversion of synthesis gas. Limiting conditions/scale-up

    SciTech Connect

    Basu, R.; Klasson, K.T.; Takriff, M.; Clausen, E.C.; Gaddy, J.L.

    1993-09-01

    The purpose of this research is to develop a technically and economically feasible process for biologically producing H(sub 2) from synthesis gas while, at the same time, removing harmful sulfur gas compounds. Six major tasks are being studied: 1. Culture development, where the best cultures are selected and conditions optimized for simultaneous hydrogen production and sulfur gas removal; 2. Mass transfer and kinetic studies in which equations necessary for process design are developed; 3. Bioreactor design studies, where the cultures chosen in Task 1 are utilized in continuous reaction vessels to demonstrate process feasibility and define operating conditions; 4. Evaluation of biological synthetic gas conversion under limiting conditions in preparation for industrial demonstration studies; 5. Process scale-up where laboratory data are scaled to larger-size units in preparation for process demonstration in a pilot-scale unit; and 6. Economic evaluation, where process simulations are used to project process economics and identify high cost areas during sensitivity analyses.

  3. HIGH EFFICIENCY DESULFURIZATION OF SYNTHESIS GAS

    SciTech Connect

    Kwang-Bok Yi; Anirban Mukherjee; Elizabeth J. Podlaha; Douglas P. Harrison

    2004-03-01

    Mixed metal oxides containing ceria and zirconia have been studied as high temperature desulfurization sorbents with the objective of achieving the DOE Vision 21 target of 1 ppmv or less H{sub 2}S in the product gas. The research was justified by recent results in this laboratory that showed that reduced CeO{sub 2}, designated CeOn (1.5 < n < 2.0), is capable of achieving the 1 ppmv target in highly reducing gas atmospheres. The addition of ZrO{sub 2} has improved the performance of oxidation catalysts and three-way automotive catalysts containing CeO{sub 2}, and was postulated to have similar beneficial effects on CeO{sub 2} desulfurization sorbents. An electrochemical method for synthesizing CeO{sub 2}-ZrO{sub 2} mixtures was developed and the products were characterized by XRD and TEM during year 01. Nanocrystalline particles having a diameter of about 5 nm and containing from approximately 10 mol% to 80 mol% ZrO{sub 2} were prepared. XRD analysis showed the product to be a solid solution at low ZrO{sub 2} contents with a separate ZrO{sub 2} phase emerging at higher ZrO{sub 2} levels. Unfortunately, the quantity of CeO{sub 2}-ZrO{sub 2} that could be prepared electrochemically was too small to permit desulfurization testing. Also during year 01 a laboratory-scale fixed-bed reactor was constructed for desulfurization testing. All components of the reactor and analytical systems that were exposed to low concentrations of H{sub 2}S were constructed of quartz, Teflon, or silcosteel. Reactor product gas composition as a function of time was determined using a Varian 3800 gas chromatograph equipped with a pulsed flame photometric detector (PFPD) for measuring low H{sub 2}S concentrations from approximately 0.1 to 10 ppmv, and a thermal conductivity detector (TCD) for higher concentrations of H{sub 2}S. Larger quantities of CeO{sub 2}-ZrO{sub 2} mixtures from other sources, including mixtures prepared in this laboratory using a coprecipitation procedure, were obtained

  4. Biological conversion of synthesis gas. Topical report: Bioreactor studies

    SciTech Connect

    Basu, R.; Klasson, K.T.; Clausen, E.C.; Gaddy, J.L.

    1993-09-01

    The purpose of the proposed research is to develop a technically and economically feasible process for biologically producing H{sub 2} from synthesis gas while, at the same time, removing harmful sulfur gas compounds. Six major tasks are being studied: culture development, where the best cultures are selected and conditions optimized for simultaneous hydrogen production and sulfur gas removal; mass transfer and kinetic studies in which equations necessary for process design are developed; bioreactor design studies, where the cultures chosen in Task 1 are utilized in continuous reaction vessels to demonstrate process feasibility and define operating conditions; evaluation of biological synthesis gas conversion under limiting conditions in preparation for industrial demonstration studies; process scale-up where laboratory data are scaled to larger-size units in preparation for process demonstration in a pilot-scale unit; and economic evaluation, where process simulations are used to project process economics and identify high cost areas during sensitivity analyses. The purpose of this report is to present results from bioreactor studies involving H{sub 2} production by water gas shift and H{sub 2}S removal to produce elemental sulfur. Many of the results for H{sub 2} production by Rhodospirillum rubrum have been presented during earlier contracts. Thus, this report concentrates mainly on H{sub 2}S conversion to elemental sulfur by R. rubrum.

  5. A Converter for Producing a Hydrogen-Containing Synthesis Gas

    NASA Astrophysics Data System (ADS)

    Malkov, Yu. P.; Molchanov, O. N.; Britov, B. K.; Fedorov, I. A.

    2016-11-01

    A computational thermodynamic and experimental investigation of the characteristics of a model of a converter for producing a hydrogen-containing synthesis gas from a hydrocarbon fuel (kerosene) with its separate delivery to thermal-oxidative and steam conversions has been carried out. It is shown that the optimum conditions of converter operation correspond to the oxidant excess coefficient in the converter's combustion chamber α > 0.5 at a temperature of the heat-transmitting wall (made from a heat-resistant KhN78T alloy (ÉI 435)) of 1200 K in the case of using a nickel corrugated tape catalyst. The content of hydrogen in the synthesis gas attains in this case 60 vol.%, and there is no release of carbon (soot) in the conversion products as well as no need for water cooling of the converter walls.

  6. Combined Gas-Liquid Plasma Source for Nanoparticle Synthesis

    NASA Astrophysics Data System (ADS)

    Burakov, V. S.; Kiris, V. V.; Nevar, A. A.; Nedelko, M. I.; Tarasenko, N. V.

    2016-09-01

    A gas-liquid plasma source for the synthesis of colloidal nanoparticles by spark erosion of the electrode material was developed and allowed the particle synthesis regime to be varied over a wide range. The source parameters were analyzed in detail for the electrical discharge conditions in water. The temperature, particle concentration, and pressure in the discharge plasma were estimated based on spectroscopic analysis of the plasma. It was found that the plasma parameters did not change signifi cantly if the condenser capacitance was increased from 5 to 20 nF. Purging the electrode gap with argon reduced substantially the pressure and particle concentration. Signifi cant amounts of water decomposition products in addition to electrode elements were found in the plasma in all discharge regimes. This favored the synthesis of oxide nanoparticles.

  7. ISOBUTANOL-METHANOL MIXTURES FROM SYNTHESIS GAS

    SciTech Connect

    Enrique Iglesia

    1998-09-01

    Isobutanol is potential as a fuel additive or precursor to methyl tert-butyl ether (MTBE). Alkali-promoted Cu/ZnO/Al{sub 2}O{sub 3} and Cu/MgO/CeO{sub 2} materials have been found to catalyze the formation of isobutanol from CO and H{sub 2} at temperatures (573-623 K) that allow their use in slurry reactors. Our studies focus on the mechanism and structural requirements for selective isobutanol synthesis on these types of catalysts. Alkali promoted Cu/MgO/CeO{sub 2}, Cu/MgO/ZnO, and CuZnAlO{sub x} materials and their individual components Cu/MgO, MgO/CeO{sub 2}, MgO and CeO{sub 2} have been prepared for the use in kinetic studies of alcohol coupling reactions, in identification of reaction intermediates, and in isobutanol synthesis at high pressures. These samples were prepared by coprecipitation of mixed nitrate solutions with an aqueous solution of KOH (2M) and K{sub 2}CO{sub 3} (1M) at 338 K at a constant pH of 9, except for Cs-Cu/ZnO/Al{sub 2}O{sub 3} at a pH of 7, in a well-stirred thermostated container. The precipitate was filtered, washed thoroughly with dioinized water at 303 K in order to remove residual K ions, and dried at 353 K overnight. Dried samples were calcined at 723 K, except for Cs-Cu/ZnO/Al{sub 2}O{sub 3} at 623 K, for 4 h in order to form the corresponding mixed oxides. Alkali addition (K or Cs) was performed by incipient wetness using K{sub 2}CO{sub 3} (0.25 M) and CH{sub 3}COOCs (0.25 M) aqueous solutions. The crystallinity and phase structures of resulting materials were analyzed by powered X-ray diffraction.

  8. Catalyst for converting synthesis gas to liquid motor fuels

    DOEpatents

    Coughlin, Peter K.

    1986-01-01

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

  9. HIGH EFFICIENCY DESULFURIZATION OF SYNTHESIS GAS

    SciTech Connect

    Anirban Mukherjee; Kwang-Bok Yi; Elizabeth J. Podlaha; Douglas P. Harrison

    2001-11-01

    Mixed metal oxides containing CeO{sub 2} and ZrO{sub 2} are being studied as high temperature desulfurization sorbents capable of achieving the DOE Vision 21 target of 1 ppmv of less H{sub 2}S. The research is justified by recent results in this laboratory that showed that reduced CeO{sub 2}, designated CeO{sub n} (1.5 < n < 2.0), is capable of achieving the 1 ppmv target in highly reducing gas atmospheres. The addition of ZrO{sub 2} has improved the performance of oxidation catalysts and three-way automotive catalysts containing CeO{sub 2}, and should have similar beneficial effects on CeO{sub 2} desulfurization sorbents. An electrochemical method for synthesizing CeO{sub 2}-ZrO{sub 2} has been developed and the products have been characterized by XRD and TEM during year 01. Nanocrystalline particles having a diameter of about 5 nm and containing from approximately 10 mol% to 80 mol% ZrO{sub 2} have been prepared. XRD showed the product to be a solid solution at low ZrO{sub 2} contents with a separate ZrO{sub 2} phase emerging at higher ZrO{sub 2} levels. Phase separation did not occur when the solid solutions were heat treated at 700 C. A flow reactor system constructed of quartz and teflon has been constructed, and a gas chromatograph equipped with a pulsed flame photometric detector (PFPD) suitable for measuring sub-ppmv levels of H{sub 2}S has been purchased with LSU matching funds. Preliminary desulfurization tests using commercial CeO{sub 2} and CeO{sub 2}-ZrO{sub 2} in highly reducing gas compositions has confirmed that CeO{sub 2}-ZrO{sub 2} is more effective than CeO{sub 2} in removing H{sub 2}S. At 700 C the product H{sub 2}S concentration using CeO{sub 2}-ZrO{sub 2} sorbent was near the 0.1 ppmv PFPD detection limit during the prebreakthrough period.

  10. Catalytic Production of Ethanol from Biomass-Derived Synthesis Gas

    SciTech Connect

    Trewyn, Brian G.; Smith, Ryan G.

    2016-06-01

    Heterogeneous catalysts have been developed for the conversion of biomass-derived synthetic gas (syngas) to ethanol. The objectives of this project were to develop a clean synthesis gas from biomass and develop robust catalysts with high selectivity and lifetime for C2 oxygenate production from biomass-derived syngas and surrogate syngas. During the timeframe for this project, we have made research progress on the four tasks: (1) Produce clean bio-oil generated from biomass, such as corn stover or switchgrass, by using fast pyrolysis system, (2) Produce clean, high pressure synthetic gas (syngas: carbon monoxide, CO, and hydrogen, H2) from bio-oil generated from biomass by gasification, (3) Develop and characterize mesoporous mixed oxide-supported metal catalysts for the selective production of ethanol and other alcohols, such as butanol, from synthesis gas, and (4) Design and build a laboratory scale synthesis gas to ethanol reactor system evaluation of the process. In this final report, detailed explanations of the research challenges associated with this project are given. Progress of the syngas production from various biomass feedstocks and catalyst synthesis for upgrading the syngas to C2-oxygenates is included. Reaction properties of the catalyst systems under different reaction conditions and different reactor set-ups are also presented and discussed. Specifically, the development and application of mesoporous silica and mesoporous carbon supports with rhodium nanoparticle catalysts and rhodium nanoparticle with manganese catalysts are described along with the significant material characterizations we completed. In addition to the synthesis and characterization, we described the activity and selectivity of catalysts in our micro-tubular reactor (small scale) and fixed bed reactor (larger scale). After years of hard work, we are proud of the work done on this project, and do believe that this work will provide a solid

  11. HIGH EFFICIENCY DESULFURIZATION OF SYNTHESIS GAS

    SciTech Connect

    Kwang-Bok Yi; Elizabeth J. Podlaha; Douglas P. Harrison

    2003-11-01

    Mixed metal oxides containing CeO{sub 2} and ZrO{sub 2} are being studied as high temperature desulfurization sorbents capable of achieving the DOE Vision 21 target of 1 ppmv or less H{sub 2}S. The research is justified by recent results in this laboratory that showed that reduced CeO{sub 2}, designated CeOn (1.5 < n < 2.0), is capable of achieving the 1 ppmv target in highly reducing gas atmospheres. The addition of ZrO{sub 2} has improved the performance of oxidation catalysts and three-way automotive catalysts containing CeO{sub 2}, and should have similar beneficial effects on CeO{sub 2} desulfurization sorbents. An electrochemical method for synthesizing CeO{sub 2}-ZrO{sub 2} was developed and the products were characterized by XRD and TEM during year 01. Nanocrystalline particles having a diameter of about 5 nm and containing from approximately 10 mol% to 80 mol% ZrO{sub 2} were prepared. XRD analysis showed the product to be a solid solution at low ZrO{sub 2} contents with a separate ZrO{sub 2} phase emerging at higher ZrO{sub 2} levels. Unfortunately, the quantity of CeO{sub 2}-ZrO{sub 2} that could be prepared electrochemically was too small to permit full desulfurization testing. Also during year 01 a laboratory-scale fixed-bed reactor was constructed for desulfurization testing. All components of the reactor and analytical systems that may be exposed to low concentrations of H{sub 2}S are constructed of quartz, Teflon, or silcosteel. Reactor product gas composition as a function of time is determined using a Varian 3800 gas chromatograph equipped with a pulsed flame photometric detector (PFPD) for measuring low H{sub 2}S concentrations (<{approx}10 ppmv) and a thermal conductivity detector (TCD) for higher concentrations of H{sub 2}S. Larger quantities of CeO{sub 2}-ZrO{sub 2} mixtures from other sources, including mixtures prepared in this laboratory using a coprecipitation procedure, have been obtained. Much of the work during year 02 consisted of

  12. HIGH EFFICIENCY DESULFURIZATION OF SYNTHESIS GAS

    SciTech Connect

    Kwang-Bok Yi; Elizabeth J. Podlaha; Douglas P. Harrison

    2002-11-01

    Mixed metal oxides containing CeO{sub 2} and ZrO{sub 2} are being studied as high temperature desulfurization sorbents capable of achieving the DOE Vision 21 target of 1 ppmv or less H{sub 2}S. The research is justified by recent results in this laboratory that showed that reduced CeO{sub 2}, designated CeO{sub n} (1.5 < n < 2.0), is capable of achieving the 1 ppmv target in highly reducing gas atmospheres. The addition of ZrO{sub 2} has improved the performance of oxidation catalysts and three-way automotive catalysts containing CeO{sub 2}, and should have similar beneficial effects on CeO{sub 2} desulfurization sorbents. An electrochemical method for synthesizing CeO{sub 2}-ZrO{sub 2} was developed and the products were characterized by XRD and TEM during year 01. Nanocrystalline particles having a diameter of about 5 nm and containing from approximately 10 mol% to 80 mol% ZrO{sub 2} were prepared. XRD showed the product to be a solid solution at low ZrO{sub 2} contents with a separate ZrO{sub 2} phase emerging at higher ZrO{sub 2} levels. Unfortunately, the quantity of CeO{sub 2}-ZrO{sub 2} that could be prepared electrochemically was too small to permit full testing in our desulfurization reactor. Also during year 01 a laboratory-scale fixed-bed reactor was constructed for desulfurization testing. All components of the reactor and analytical systems that may be exposed to low concentrations of H{sub 2}S are constructed of quartz, Teflon, or silcosteel. Reactor product gas composition as a function of time is determined using a Varian 3800 gas chromatograph equipped with a pulsed flame photometric detector (PFPD) for measuring low H{sub 2}S concentrations ({approx}< 10 ppmv) and a thermal conductivity detector (TCD) for higher concentrations of H{sub 2}S. Larger quantities of CeO{sub 2}-ZrO{sub 2} mixtures from other sources, including mixtures prepared in this laboratory using a coprecipitation procedure, have been obtained. Characterization and desulfurization

  13. Vanadium oxide based materials: Synthesis, characterization and gas sensing properties

    NASA Astrophysics Data System (ADS)

    Ayesh, Samar I.

    In recent years, the demand for gas sensors based on safety and process control requirements has been expanding. The reason for such demand sterns from environmental and safety concerns since the toxic gases released from automobile exhausts and chemical plants can directly or indirectly pollute our environment and affect our health. Among the chemicals studied, nitrogen oxide (NOx) gases are among the most dangerous air pollutants. Transition metal oxide clusters (or polyoxometalates) provide an exciting opportunity for the design and synthesis of a new generation of materials for efficient NOx sensing. Polyoxometalates are an important and fast emerging class of compounds that exhibit many remarkable properties. Chapter 1 provides introduction and background of chemical sensors. It describes the need for gas sensors and the current status of research in the area of NOx gas sensors in particular. A description of polyoxmetalates and their relevance as potential novel gas sensor materials is also given. Chapter 2 describes the synthesis and characterization by FTIR spectroscopy, elemental analysis, thermogravimetric analysis, manganometric titration, bond valence sum calculation, temperature dependent magnetic properties studies, electron paramagnetic resonance, and complete single crystal X-ray diffraction analysis of newly prepared vanadium oxide based-systems that have been discovered during the course of this work. First, the system containing arrays of decavanadates networked by extensive hydrogen bonding with cyclic nitrogen bases are described. This is followed by the mixed-valence vanadium oxide cluster, [VV 13VIV3O42(Cl)]-7, containing a hitherto unknown vanadium oxide framework structure. Finally the synthesis of 3D-framework materials is described. These compounds have highly symmetrical closely related three-dimensional framework structures consisting vanadium oxide shells {V18O42(XO4)} linked via heterometallic atoms {M' = Cd, Zn} into three

  14. High octane ethers from synthesis gas-derived alcohols. Technical progress report, October--December 1991

    SciTech Connect

    Klier, K.; Herman, R.G.; Johansson, M.; Feeley, O.C.

    1992-01-01

    The objective of the proposed research is to synthesize high octane ethers, primarily methyl isobutyl ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from H{sub 2}/CO/CO{sub 2} coal-derived synthesis gas via alcohol mixtures that are rich in methanol and 2-methyl-1-propanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers.

  15. Synthesis of organic geochemical data from the Eastern Gas Shales

    SciTech Connect

    Zielinski, R. E.; McIver, R. D.

    1982-01-01

    Over 2400 core and cuttings samples of Upper Devonian shales from wells in the Appalachian, Illinois, and Michigan Basins have been characterized by organic geochemical methods to provide a basis for accelerating the exploitation of this unconventional, gas-rich resource. This work was part of a program initiated to provide industry with criteria for locating the best areas for future drilling and for the development of stimulation methods that will make recovery of the resource economically attractive. The geochemical assessment shows that the shale, in much of the Appalachian, Illinois, and Michigan Basins is source rock that is capable of generating enormous quantities of gas. In some areas the shales are also capable of generating large quantities of oil as well. The limiting factors preventing these sources from realizing most of their potential are their very low permeabilities and the paucity of potential reservoir rocks. This geochemical data synthesis gives direction to future selection of sites for stimulation research projects in the Appalachian Basin by pinpointing those areas where the greatest volumes of gas are contained in the shale matrix. Another accomplishment of the geochemical data synthesis is a new estimate of the total resource of the Appalachian Basin. The new estimate of 2500 TCF is 25 percent greater than the highest previous estimates. This gives greater incentive to government and industry to continue the search for improved stimulation methods, as well as for improved methods for locating the sites where those improved stimulation methods can be most effectively applied.

  16. Direct catalytic conversion of synthesis gas to lower olefins

    SciTech Connect

    Janardanarao, M. )

    1990-09-01

    Direct conversion of synthesis gas to lower olefins has been considered as a possible solution to meet the growing demand for chemical feedstocks such as ethylene, propylene, and butylenes. This review covers the various catalyst systems and operating conditions that have been used in meeting this objective. Though the product distribution in Fischer--Tropsch synthesis is governed by the existence of an Anderson--Schultz--Flory polymerization model, certain modifications in the catalyst formulations have produced a shift toward lower molecular weight olefins. At the present time, the yields and selectivities of lower olefins are far from optimal, but continued research efforts in this area may lead to the development of stable catalyst systems capable of producing highly desirable distributions of lower olefins.

  17. THE SYNTHESIS AND EVALUATION OF NEW BASE STOCK FLUIDS FOR GAS TURBINE APPLICATION

    DTIC Science & Technology

    GAS TURBINES, *LUBRICANTS, *OXYGEN HETEROCYCLIC COMPOUNDS, ALKOXY RADICALS, ALKYL RADICALS, AMIDES, ANILINES , CHEMICAL REACTIONS , DISPLACEMENT... REACTIONS , INFRARED SPECTROSCOPY, LUBRICATION, OXIDATION, PHENYL RADICALS, STABILITY, SUBSTITUTION REACTIONS , SYNTHESIS, TEMPERATURE, VISCOSITY.

  18. Electron-beam synthesis of fuel in the gas phase

    NASA Astrophysics Data System (ADS)

    Ponomarev, A. V.; Holodkova, E. M.; Ershov, B. G.

    2012-09-01

    Electron-beam synthesis of liquid fuel from gaseous alkanes was upgraded for formation of conventional and alternative fuel from biomass or pyrolysis oil. Bio-feedstock conversion algorithm includes two consecutive stages: (1) initial macromolecules' transformation to low-molecular-weight intermediates; (2) transformation of these intermediates to stable fuel in gaseous alkanes' atmosphere. Radicals originated from alkanes participate in alkylation/hydrogenation of biomass intermediates. Chemical fixation of gaseous alkanes is amplified in the presence of biomass derivatives due to suppression of gas regeneration reactions, higher molar mass of reagents and lower volatility of radiolytic intermediates.

  19. Synthesis of Isobutene and Isobutane from Synthesis Gas. A Literature Review Since 1992

    SciTech Connect

    Petkovic, Lucia M.; Ginosar, Daniel M.

    2012-04-01

    The isosynthesis reaction is commonly referred as the reaction that converts selectively synthesis gas to isobutene and isobutane. The main feature of this reaction is the production of branched hydrocarbons in higher proportion with respect to linear hydrocarbons than expected from thermodynamic equilibrium and with a molecular weight distribution favoring iso-C4 hydrocarbons. This article reviews and summarizes isosynthesis research results reported in the open scientific literature with emphasis on the articles published in the last two decades.

  20. OPTIMIZING SYNTHESIS GAS YIELD FROM THE CROSS DRAFT GASIFICATION OF WOODY BIOMASS

    EPA Science Inventory

    Biomass can be gasified to yield synthesis gas, tars, and ash. The process is governed by a number of parameters such as the temperature of the gasifying medium (in this case air), and the moisture content of the feedstock. Synthesis gas from gasifying wood pellets was collected ...

  1. Catalyst for converting synthesis gas to light olefins

    DOEpatents

    Rao, V. Udaya S.; Gormley, Robert J.

    1982-01-01

    A catalyst and process for making same useful in the catalytic hydrogenation of carbon monoxide in which a silicalite support substantially free of aluminum is soaked in an aqueous solution of iron and potassium salts wherein the iron and potassium are present in concentrations such that the dried silicalite has iron present in the range of from about 5 to about 25 percent by weight and has potassium present in an amount not less than about 0.2 percent by weight, and thereafter the silicalite is dried and combined with amorphous silica as a binder for pellets, the catalytic pellets are used to convert synthesis gas to C.sub.2 -C.sub.4 olefins.

  2. Gas-phase synthesis of magnetic metal/polymer nanocomposites.

    PubMed

    Starsich, Fabian H L; Hirt, Ann M; Stark, Wendelin J; Grass, Robert N

    2014-12-19

    Highly magnetic metal Co nanoparticles were produced via reducing flame spray pyrolysis, and directly coated with an epoxy polymer in flight. The polymer content in the samples varied between 14 and 56 wt% of nominal content. A homogenous dispersion of Co nanoparticles in the resulting nanocomposites was visualized by electron microscopy. The size and crystallinity of the metallic fillers was not affected by the polymer, as shown by XRD and magnetic hysteresis measurements. The good control of the polymer content in the product nanocomposite was shown by elemental analysis. Further, the successful polymerization in the gas phase was demonstrated by electron microscopy and size measurements. The presented effective, dry and scalable one-step synthesis method for highly magnetic metal nanoparticle/polymer composites presented here may drastically decrease production costs and increase industrial yields.

  3. Gas-phase synthesis of magnetic metal/polymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Starsich, Fabian H. L.; Hirt, Ann M.; Stark, Wendelin J.; Grass, Robert N.

    2014-12-01

    Highly magnetic metal Co nanoparticles were produced via reducing flame spray pyrolysis, and directly coated with an epoxy polymer in flight. The polymer content in the samples varied between 14 and 56 wt% of nominal content. A homogenous dispersion of Co nanoparticles in the resulting nanocomposites was visualized by electron microscopy. The size and crystallinity of the metallic fillers was not affected by the polymer, as shown by XRD and magnetic hysteresis measurements. The good control of the polymer content in the product nanocomposite was shown by elemental analysis. Further, the successful polymerization in the gas phase was demonstrated by electron microscopy and size measurements. The presented effective, dry and scalable one-step synthesis method for highly magnetic metal nanoparticle/polymer composites presented here may drastically decrease production costs and increase industrial yields.

  4. Biological upgrading of coal-derived synthesis gas: Final report

    SciTech Connect

    Barik, S.; Johnson, E.R.; Ko, C.W.; Clausen, E.C.; Gaddy, J.L.

    1986-10-01

    The technical feasibility of the biological conversion of coal synthesis gas to methane has been demonstrated in the University of Arkansas laboratories. Cultures of microorganisms have been developed which achieve total conversion in the water gas shift and methanation reactions in either mixed or pure cultures. These cultures carry out these conversions at ordinary temperatures and pressures, without sulfur toxicity. Several microorganisms have been identified as having commercial potential for producing methane. These include a mixed culture of unidentified bacteria; P. productus which produces acetate, a methane precursor; and Methanothrix sp., which produces methane from acetate. These cultures have been used in mixed reactors and immobilized cell reactors to achieve total CO and H/sub 2/ conversion in a retention time of less than two hours, quite good for a biological reactor. Preliminary economic projections indicate that a biological methanation plant with a size of 5 x 10/sup 10/ Btu/day can be economically attractive. 42 refs., 26 figs., 86 tabs.

  5. Bioconversion of coal derived synthesis gas to liquid fuels

    NASA Astrophysics Data System (ADS)

    Jain, M. K.; Worden, R. M.; Grethlein, A.

    1994-07-01

    The overall objective of the project is to develop an integrated two-stage fermentation process for conversion of coal-derived synthesis gas to a mixture of alcohols. This is achieved in two steps. In the first step, Butyribacterium methylotrophicum converts carbon monoxide (CO) to butyric and acetic acids. Subsequent fermentation of the acids by Clostridium acetobutylicum leads to the production of butanol and ethanol. The tasks for this quarter were: development/isolation of superior strains for fermentation of syngas; evaluation of bioreactor configuration for improved mass transfer of syngas; recovery of carbon and electrons from H2-CO2; initiation of pervaporation for recovery of solvents; and selection of solid support material for trickle-bed fermentation. Technical progress included the following: butyrate production was enhanced during H2/CO2 (50/50) batch fermentation; isolation of CO-utilizing anaerobic strains is in progress; pressure (15 psig) fermentation was evaluated as a means of increasing CO availability; polyurethane foam packing material was selected for trickle bed solid support; cell recycle fermentation on syngas operated for 3 months. Acetate was the primary product at pH 6.8; trickle bed and gas lift fermentor designs were modified after initial water testing; and pervaporation system was constructed (No alcohol selectivity was shown with the existing membranes during initial start-up).

  6. Gas-phase synthesis of semiconductor nanocrystals and its applications

    NASA Astrophysics Data System (ADS)

    Mandal, Rajib

    Luminescent nanomaterials is a newly emerging field that provides challenges not only to fundamental research but also to innovative technology in several areas such as electronics, photonics, nanotechnology, display, lighting, biomedical engineering and environmental control. These nanomaterials come in various forms, shapes and comprises of semiconductors, metals, oxides, and inorganic and organic polymers. Most importantly, these luminescent nanomaterials can have different properties owing to their size as compared to their bulk counterparts. Here we describe the use of plasmas in synthesis, modification, and deposition of semiconductor nanomaterials for luminescence applications. Nanocrystalline silicon is widely known as an efficient and tunable optical emitter and is attracting great interest for applications in several areas. To date, however, luminescent silicon nanocrystals (NCs) have been used exclusively in traditional rigid devices. For the field to advance towards new and versatile applications for nanocrystal-based devices, there is a need to investigate whether these NCs can be used in flexible and stretchable devices. We show how the optical and structural/morphological properties of plasma-synthesized silicon nanocrystals (Si NCs) change when they are deposited on stretchable substrates made of polydimethylsiloxane (PDMS). Synthesis of these NCs was performed in a nonthermal, low-pressure gas phase plasma reactor. To our knowledge, this is the first demonstration of direct deposition of NCs onto stretchable substrates. Additionally, in order to prevent oxidation and enhance the luminescence properties, a silicon nitride shell was grown around Si NCs. We have demonstrated surface nitridation of Si NCs in a single step process using non?thermal plasma in several schemes including a novel dual-plasma synthesis/shell growth process. These coated NCs exhibit SiNx shells with composition depending on process parameters. While measurements including

  7. Selective removal of ethylene, a deposit precursor, from a "dirty" synthesis gas stream via gas-phase partial oxidation.

    PubMed

    Villano, Stephanie M; Hoffmann, Jessica; Carstensen, Hans-Heinrich; Dean, Anthony M

    2010-06-17

    A fundamental issue in the gasification of biomass is that in addition to the desired synthesis gas product (a mixture of H(2) and CO), the gasifier effluent contains other undesirable products that need to be removed before any further downstream processing can occur. This work assesses the potential to selectively remove hydrocarbons from a synthesis gas stream via gas-phase partial oxidation. Specifically, the partial oxidation of methane-doped, ethylene-doped, and methane/ethylene-doped model synthesis gas mixtures has been investigated at ambient pressures over a temperature range of 760-910 degrees C and at residence times ranging from 0.4 to 2.4 s using a tubular flow reactor. For the synthesis gas mixtures that contain either methane or ethylene, the addition of oxygen substantially reduces the hydrocarbon concentration while only a small reduction in the hydrogen concentration is observed. For the synthesis gas mixtures doped with both methane and ethylene, the addition of oxygen preferentially removes ethylene while the concentrations of methane and hydrogen remain relatively unaffected. These results are compared to the predictions of a plug flow model using a reaction mechanism that is designed to describe the pyrolysis and partial oxidation of small hydrocarbon species. The agreement between the experimental observations and the model predictions is quite good, allowing us to explore the underlying chemistry that leads to the hydrocarbon selective oxidation. The implications of these results are briefly discussed in terms of using synthesis gas to produce liquid fuels and electrical power via a solid oxide fuel cell.

  8. Gas-Phase Combustion Synthesis of Nonoxide Nanoparticles in Microgravity

    NASA Technical Reports Server (NTRS)

    Axelbaum, R. L.; Kumfer, B. M.; Sun, Z.; Chao, B. H.

    2001-01-01

    Gas-phase combustion synthesis is a promising process for creating nanoparticles for the growing nanostructure materials industry. The challenges that must be addressed are controlling particle size, preventing hard agglomerates, maintaining purity, and, if nonoxides are synthesized, protecting the particles from oxidation and/or hydrolysis during post-processing. Sodium-halide Flame Encapsulation (SFE) is a unique methodology for producing nonoxide nanoparticles that addresses these challenges. This flame synthesis process incorporates sodium and metal-halide chemistry, resulting in nanoparticles that are encapsulated in salt during the early stages of their growth in the flame. Salt encapsulation has been shown to allow control of particle size and morphology, while serving as an effective protective coating for preserving the purity of the core particles. Metals and compounds that have been produced using this technology include Al, W, Ti, TiB2, AlN, and composites of W-Ti and Al-AlN. Oxygen content in SFE synthesized nano- AlN has been measured by neutron activation analysis to be as low as 0.54wt.%, as compared to over 5wt.% for unprotected AlN of comparable size. The overall objective of this work is to study the SFE process and nano-encapsulation so that they can be used to produce novel and superior materials. SFE experiments in microgravity allow the study of flame and particle dynamics without the influence of buoyancy forces. Spherical sodium-halide flames are produced in microgravity by ejecting the halide from a spherical porous burner into a quiescent atmosphere of sodium vapor and argon. Experiments are performed in the 2.2 sec Drop Tower at the NASA-Glenn Research Center. Numerical models of the flame and particle dynamics were developed and are compared with the experimental results.

  9. Plasma reforming and partial oxidation of hydrocarbon fuel vapor to produce synthesis gas and/or hydrogen gas

    DOEpatents

    Kong, Peter C.; Detering, Brent A.

    2003-08-19

    Methods and systems for treating vapors from fuels such as gasoline or diesel fuel in an internal combustion engine, to form hydrogen gas or synthesis gas, which can then be burned in the engine to produce more power. Fuel vapor, or a mixture of fuel vapor and exhaust gas and/or air, is contacted with a plasma, to promote reforming reactions between the fuel vapor and exhaust gas to produce carbon monoxide and hydrogen gas, partial oxidation reactions between the fuel vapor and air to produce carbon monoxide and hydrogen gas, or direct hydrogen and carbon particle production from the fuel vapor. The plasma can be a thermal plasma or a non-thermal plasma. The plasma can be produced in a plasma generating device which can be preheated by contact with at least a portion of the hot exhaust gas stream, thereby decreasing the power requirements of the plasma generating device.

  10. Plasma Reforming And Partial Oxidation Of Hydrocarbon Fuel Vapor To Produce Synthesis Gas And/Or Hydrogen Gas

    DOEpatents

    Kong, Peter C.; Detering, Brent A.

    2004-10-19

    Methods and systems are disclosed for treating vapors from fuels such as gasoline or diesel fuel in an internal combustion engine, to form hydrogen gas or synthesis gas, which can then be burned in the engine to produce more power. Fuel vapor, or a mixture of fuel vapor and exhaust gas and/or air, is contacted with a plasma, to promote reforming reactions between the fuel vapor and exhaust gas to produce carbon monoxide and hydrogen gas, partial oxidation reactions between the fuel vapor and air to produce carbon monoxide and hydrogen gas, or direct hydrogen and carbon particle production from the fuel vapor. The plasma can be a thermal plasma or a non-thermal plasma. The plasma can be produced in a plasma generating device which can be preheated by contact with at least a portion of the hot exhaust gas stream, thereby decreasing the power requirements of the plasma generating device.

  11. Ion transport membrane reactor systems and methods for producing synthesis gas

    DOEpatents

    Repasky, John Michael

    2015-05-12

    Embodiments of the present invention provide cost-effective systems and methods for producing a synthesis gas product using a steam reformer system and an ion transport membrane (ITM) reactor having multiple stages, without requiring inter-stage reactant injections. Embodiments of the present invention also provide techniques for compensating for membrane performance degradation and other changes in system operating conditions that negatively affect synthesis gas production.

  12. ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS. FINAL QUARTERLY STATUS REPORT

    SciTech Connect

    1999-04-01

    The overall objectives of this program are to investigate potential technologies for the conversion of synthesis gas to oxygenated and hydrocarbon fuels and industrial chemicals, and to demonstrate the most promising technologies at DOE's LaPorte, Texas, Slurry Phase Alternative Fuels Development Unit (AFDU). The program will involve a continuation of the work performed under the Alternative Fuels from Coal-Derived Synthesis Gas Program and will draw upon information and technologies generated in parallel current and future DOE-funded contracts.

  13. ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS. FINAL QUARTERLY STATUS REPORT NO. 10

    SciTech Connect

    1998-11-01

    The overall objectives of this program are to investigate potential technologies for the conversion of synthesis gas to oxygenated and hydrocarbon fuels and industrial chemicals, and to demonstrate the most promising technologies at DOE's LaPorte, Texas, Slurry Phase Alternative Fuels Development Unit (AFDU). The program will involve a continuation of the work performed under the Alternative Fuels from Coal-Derived Synthesis Gas Program and will draw upon information and technologies generated in parallel current and future DOE-funded contracts.

  14. Synthesis of dimethyl ether and alternative fuels in the liquid phase from coal-derived synthesis gas. Final technical report

    SciTech Connect

    Not Available

    1993-02-01

    Through the mid-1980s, Air Products has brought the liquid phase approach to a number of other synthesis gas reactions where effective heat management is a key issue. In 1989, in response to DOE`s PRDA No. DE-RA22-88PC88805, Air Products proposed a research and development program entitled ``Synthesis of Dimethyl Ether and Alternative Fuels in the Liquid Phase from Coal Derived Syngas.`` The proposal aimed at extending the LPMEOH experience to convert coal-derived synthesis gas to other useful fuels and chemicals. The work proposed included development of a novel one-step synthesis of dimethyl ether (DME) from syngas, and exploration of other liquid phase synthesis of alternative fuel directly from syngas. The one-step DME process, conceived in 1986 at Air Products as a means of increasing syngas conversion to liquid products, envisioned the concept of converting product methanol in situ to DME in a single reactor. The slurry reactor based liquid phase technology is ideally suited for such an application, since the second reaction (methanol to DME) can be accomplished by adding a second catalyst with dehydration activity to the methanol producing reactor. An area of exploration for other alternative fuels directly from syngas was single-step slurry phase synthesis of hydrocarbons via methanol and DME as intermediates. Other possibilities included the direct synthesis of mixed alcohols and mixed ethers in a slurry reactor.

  15. Carbon dioxide capture and use: organic synthesis using carbon dioxide from exhaust gas.

    PubMed

    Kim, Seung Hyo; Kim, Kwang Hee; Hong, Soon Hyeok

    2014-01-13

    A carbon capture and use (CCU) strategy was applied to organic synthesis. Carbon dioxide (CO2) captured directly from exhaust gas was used for organic transformations as efficiently as hyper-pure CO2 gas from a commercial source, even for highly air- and moisture-sensitive reactions. The CO2 capturing aqueous ethanolamine solution could be recycled continuously without any diminished reaction efficiency.

  16. Gas-Phase Combustion Synthesis of Aluminum Nitride Powder

    NASA Technical Reports Server (NTRS)

    Axelbaum, R. L.; Lottes, C. R.; Huertas, J. I.; Rosen, L. J.

    1996-01-01

    Due to its combined properties of high electrical resistivity and high thermal conductivity aluminum nitride (AlN) is a highly desirable material for electronics applications. Methods are being sought for synthesis of unagglomerated, nanometer-sized powders of this material, prepared in such a way that they can be consolidated into solid compacts having minimal oxygen content. A procedure for synthesizing these powders through gas-phase combustion is described. This novel approach involves reacting AlCl3, NH3, and Na vapors. Equilibrium thermodynamic calculations show that 100% yields can be obtained for these reactants with the products being AlN, NaCl, and H2. The NaCl by-product is used to coat the AlN particles in situ. The coating allows for control of AlN agglomeration and protects the powders from hydrolysis during post-flame handling. On the basis of thermodynamic and kinetic considerations, two different approaches were employed to produce the powder, in co-flow diffusion flame configurations. In the first approach, the three reactants were supplied in separate streams. In the second, the AlCl3 and NH3 were premixed with HCl and then reacted with Na vapor. X-ray diffraction (XRD) spectra of as-produced powders show only NaCl for the first case and NaCl and AlN for the second. After annealing at 775 C tinder dynamic vacuum, the salt was removed and XRD spectra of powders from both approaches show only AlN. Aluminum metal was also produced in the co-flow flame by reacting AlCl3 with Na. XRD spectra of as-produced powders show the products to be only NaCl and elemental aluminum.

  17. Engineering development of ceramic membrane reactor system for converting natural gas to hydrogen and synthesis gas for liquid transportation fuels

    SciTech Connect

    1998-07-01

    The objective of this contract is to research, develop and demonstrate a novel ceramic membrane reactor system for the low-cost conversion of natural gas to synthesis gas and hydrogen for liquid transportation fuels: the ITM Syngas process. Through an eight-year, three-phase program, the technology will be developed and scaled up to obtain the technical, engineering, operating and economic data necessary for the final step to full commercialization of the Gas-to-Liquids (GTL) conversion technology. This report is a summary of activities through June 1998.

  18. High octane ethers from synthesis gas-derived alcohols. Technical progress report, July 1, 1991--September 30, 1991

    SciTech Connect

    Klier, K.; Herman, R.G.; Johannson, M.; Feeley, O.C.; Bogar, S.; Lawson, E.; Kieke, M.

    1991-11-01

    The objective of the proposed research is to synthesize high octane ethers, primarily methyl isobuty ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from H{sub 2}/CO/CO{sub 2} coal-derived synthesis gas via alcohol mixtures that are rich in methanol and 2-methyl-1-butanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers.

  19. Techno-economic analysis for the evaluation of three UCG synthesis gas end use approaches

    NASA Astrophysics Data System (ADS)

    Nakaten, Natalie; Kempka, Thomas; Burchart-Korol, Dorota; Krawczyk, Piotr; Kapusta, Krzysztof; Stańczyk, Krzysztof

    2016-04-01

    Underground coal gasification (UCG) enables the utilization of coal reserves that are economically not exploitable because of complex geological boundary conditions. In the present study we investigate UCG as a potential economic approach for conversion of deep-seated coals into a synthesis gas and its application within three different utilization options. Related to geological boundary conditions and the chosen gasification agent, UCG synthesis gas composes of varying methane, hydrogen, nitrogen, carbon monoxide and carbon dioxide amounts. In accordance to its calorific value, the processed UCG synthesis gas can be utilized in different manners, as for electricity generation in a combined cycle power plant or for feedstock production making use of its various chemical components. In the present study we analyze UCG synthesis gas utilization economics in the context of clean electricity generation with an integrated carbon capture and storage process (CCS) as well as synthetic fuel and fertilizer production (Kempka et al., 2010) based on a gas composition achieved during an in situ UCG trial in the Wieczorek Mine. Hereby, we also consider chemical feedstock production in order to mitigate CO2 emissions. Within a sensitivity analysis of UCG synthesis gas calorific value variations, we produce a range of capital and operational expenditure bandwidths that allow for an economic assessment of different synthesis gas end use approaches. To carry out the integrated techno-economic assessment of the coupled systems and the sensitivity analysis, we adapted the techno-economic UCG-CCS model developed by Nakaten et al. (2014). Our techno-economic modeling results demonstrate that the calorific value has a high impact on the economics of UCG synthesis gas utilization. In the underlying study, the synthesis gas is not suitable for an economic competitive electricity generation, due to the relatively low calorific value of 4.5 MJ/Nm³. To be a profitable option for electricity

  20. Low cost hydrogen/novel membrane technology for hydrogen separation from synthesis gas

    SciTech Connect

    Baker, R.W.; Bell, C.M.; Chow, P.; Louie, J.; Mohr, J.M.; Peinemann, K.V.; Pinnau, I.; Wijmans, J.G.; Gottschlich, D.E.; Roberts, D.L.

    1990-10-01

    The production of hydrogen from synthesis gas made by gasification of coal is expensive. The separation of hydrogen from synthesis gas is a major cost element in the total process. In this report we describe the results of a program aimed at the development of membranes and membrane modules for the separation and purification of hydrogen from synthesis gas. The performance properties of the developed membranes were used in an economic evaluation of membrane gas separation systems in the coal gasification process. Membranes tested were polyetherimide and a polyamide copolymer. The work began with an examination of the chemical separations required to produce hydrogen from synthesis gas, identification of three specific separations where membranes might be applicable. A range of membrane fabrication techniques and module configurations were investigated to optimize the separation properties of the membrane materials. Parametric data obtained were used to develop the economic comparison of processes incorporating membranes with a base-case system without membranes. The computer calculations for the economic analysis were designed and executed. Finally, we briefly investigated alternative methods of performing the three separations in the production of hydrogen from synthesis gas. The three potential opportunities for membranes in the production of hydrogen from synthesis gas are: (1) separation of hydrogen from nitrogen as the final separation in a air-blown or oxygen-enriched air-blown gasification process, (2) separation of hydrogen from carbon dioxide and hydrogen sulfide to reduce or eliminate the conventional ethanolamine acid gas removal unit, and (3) separation of hydrogen and/or carbon dioxide form carbon monoxide prior to the shift reactor to influence the shift reaction. 28 refs., 54 figs., 40 tabs.

  1. Autothermal reforming of natural gas to synthesis gas:reference: KBR paper #2031.

    SciTech Connect

    Mann, David; Rice, Steven, D.

    2007-04-01

    This Project Final Report serves to document the project structure and technical results achieved during the 3-year project titled Advanced Autothermal Reformer for US Dept of Energy Office of Industrial Technology. The project was initiated in December 2001 and was completed March 2005. It was a joint effort between Sandia National Laboratories (Livermore, CA), Kellogg Brown & Root LLC (KBR) (Houston, TX) and Sued-Chemie (Louisville, KY). The purpose of the project was to develop an experimental capability that could be used to examine the propensity for soot production in an Autothermal Reformer (ATR) during the production of hydrogen-carbon monoxide synthesis gas intended for Gas-to-Liquids (GTL) applications including ammonia, methanol, and higher hydrocarbons. The project consisted of an initial phase that was focused on developing a laboratory-scale ATR capable of reproducing conditions very similar to a plant scale unit. Due to budget constraints this effort was stopped at the advanced design stages, yielding a careful and detailed design for such a system including ATR vessel design, design of ancillary feed and let down units as well as a PI&D for laboratory installation. The experimental effort was then focused on a series of measurements to evaluate rich, high-pressure burner behavior at pressures as high as 500 psi. The soot formation measurements were based on laser attenuation at a view port downstream of the burner. The results of these experiments and accompanying calculations show that soot formation is primarily dependent on oxidation stoichiometry. However, steam to carbon ratio was found to impact soot production as well as burner stability. The data also showed that raising the operating pressure while holding mass flow rates constant results in considerable soot formation at desirable feed ratios. Elementary reaction modeling designed to illuminate the role of CO{sub 2} in the burner feed showed that the conditions in the burner allow for the

  2. Synthesis Gas (Syngas)-Derived Medium-Chain-Length Polyhydroxyalkanoate Synthesis in Engineered Rhodospirillum rubrum

    PubMed Central

    Heinrich, Daniel; Raberg, Matthias; Fricke, Philipp; Kenny, Shane T.; Morales-Gamez, Laura; Babu, Ramesh P.; O'Connor, Kevin E.

    2016-01-01

    ABSTRACT The purple nonsulfur alphaproteobacterium Rhodospirillum rubrum S1 was genetically engineered to synthesize a heteropolymer of mainly 3-hydroxydecanoic acid and 3-hydroxyoctanoic acid [P(3HD-co-3HO)] from CO- and CO2-containing artificial synthesis gas (syngas). For this, genes from Pseudomonas putida KT2440 coding for a 3-hydroxyacyl acyl carrier protein (ACP) thioesterase (phaG), a medium-chain-length (MCL) fatty acid coenzyme A (CoA) ligase (PP_0763), and an MCL polyhydroxyalkanoate (PHA) synthase (phaC1) were cloned and expressed under the control of the CO-inducible promoter PcooF from R. rubrum S1 in a PHA-negative mutant of R. rubrum. P(3HD-co-3HO) was accumulated to up to 7.1% (wt/wt) of the cell dry weight by a recombinant mutant strain utilizing exclusively the provided gaseous feedstock syngas. In addition to an increased synthesis of these medium-chain-length PHAs (PHAMCL), enhanced gene expression through the PcooF promoter also led to an increased molar fraction of 3HO in the synthesized copolymer compared with the Plac promoter, which regulated expression on the original vector. The recombinant strains were able to partially degrade the polymer, and the deletion of phaZ2, which codes for a PHA depolymerase most likely involved in intracellular PHA degradation, did not reduce mobilization of the accumulated polymer significantly. However, an amino acid exchange in the active site of PhaZ2 led to a slight increase in PHAMCL accumulation. The accumulated polymer was isolated; it exhibited a molecular mass of 124.3 kDa and a melting point of 49.6°C. With the metabolically engineered strains presented in this proof-of-principle study, we demonstrated the synthesis of elastomeric second-generation biopolymers from renewable feedstocks not competing with human nutrition. IMPORTANCE Polyhydroxyalkanoates (PHAs) are natural biodegradable polymers (biopolymers) showing properties similar to those of commonly produced petroleum-based nondegradable

  3. Noble gas trapping and fractionation during synthesis of carbonaceous matter. [in meteorites

    NASA Technical Reports Server (NTRS)

    Frick, U.; Mack, R.; Chang, S.

    1979-01-01

    An investigation of noble gas entrapment during synthesis of carbonaceous, macromolecular, and kerogen-like substances is presented. High molecular weight organic matter synthesized in aqueous condensation reactions contained little gas, and the composition was consistent with fractionation due to noble gas solubility in water; however, propane soot produced during a modified Miller-Urey experiment in an aritificial gas mixture contained high concentrations of trapped noble gases that displayed strong elemental fractionation from their reservoirs. It is concluded that theses experiemnts show that processes exist for synthesis of carbonaceous carriers that result in high noble gas concentrations and strong elemental fractionation at temperatures well above those required by absorption to achieve similar effects.

  4. Literature Review and Synthesis for the Natural Gas Infrastructure

    SciTech Connect

    Folga, Stephen; Talaber, Leah; McLamore, Michael; Kraucunas, Ian; McPherson, Timothy; Parrott, Lori; Manzanares, Trevor

    2015-06-01

    The efficient and effective movement of natural gas from producing regions to consuming regions requires an extensive and elaborate transportation system. In many instances, natural gas produced from a particular well has to travel a great distance to reach its point of use. The transportation system for natural gas consists of a complex network of pipelines designed to quickly and efficiently transport the gas from its origin to areas of high demand. The transportation of natural gas is closely linked to its storage: If the natural gas being transported is not immediately required, it can be put into storage facilities until it is needed. A description of the natural gas transmission, storage, and distribution (TS&D) sector is provided as follows.

  5. DEVELOPMENT OF ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS

    SciTech Connect

    Peter J. Tijrn

    2003-05-31

    This Final Report for Cooperative Agreement No. DE-FC22-95PC93052, the ''Development of Alternative Fuels and Chemicals from Synthesis Gas,'' was prepared by Air Products and Chemicals, Inc. (Air Products), and covers activities from 29 December 1994 through 31 July 2002. The overall objectives of this program were to investigate potential technologies for the conversion of synthesis gas (syngas), a mixture primarily of hydrogen (H{sub 2}) and carbon monoxide (CO), to oxygenated and hydrocarbon fuels and industrial chemicals, and to demonstrate the most promising technologies at the LaPorte, Texas Alternative Fuels Development Unit (AFDU). Laboratory work was performed by Air Products and a variety of subcontractors, and focused on the study of the kinetics of production of methanol and dimethyl ether (DME) from syngas, the production of DME using the Liquid Phase Dimethyl Ether (LPDME{trademark}) Process, the conversion of DME to fuels and chemicals, and the production of other higher value products from syngas. Four operating campaigns were performed at the AFDU during the performance period. Tests of the Liquid Phase Methanol (LPMEOH{trademark}) Process and the LPDME{trademark} Process were made to confirm results from the laboratory program and to allow for the study of the hydrodynamics of the slurry bubble column reactor (SBCR) at a significant engineering scale. Two campaigns demonstrated the conversion of syngas to hydrocarbon products via the slurry-phase Fischer-Tropsch (F-T) process. Other topics that were studied within this program include the economics of production of methyl tert-butyl ether (MTBE), the identification of trace components in coal-derived syngas and the means to economically remove these species, and the study of systems for separation of wax from catalyst in the F-T process. The work performed under this Cooperative Agreement has continued to promote the development of technologies that use clean syngas produced from any one of a

  6. Alternative fuels and chemicals from synthesis gas. Quarterly report, April 1--June 30, 1995

    SciTech Connect

    1995-12-31

    The overall objectives of this program are to investigate potential technologies for the conversion of synthesis gas to oxygenated and hydrocarbon fuels and industrial chemicals, and to demonstrate the most promising technologies at DOE`s LaPorte, Texas, Slurry Phase Alternative Fuels Development Unit (AFDU). The program will involve a continuation of the work performed under the Alternative Fuels from Coal-Derived Synthesis Gas Program and will draw upon information and technologies generated in parallel current and future DOE-funded contracts. The paper reports the progress on the following tasks: engineering and modifications: AFDU shakedown, operations, deactivation and disposal; and research and development on new processes for DME, chemistry and catalyst development, and oxygenates via synthesis gas.

  7. Alternative fuels and chemicals from synthesis gas. Fourth quarterly report, 1994

    SciTech Connect

    1997-10-01

    The overall objectives of this program are to investigate potential technologies for the conversion of synthesis gas to oxygenated and hydrocarbon fuels and industrial chemicals, and to demonstrate the most promising technologies at DOE`s LaPorte, Texas, Slurry Phase Alternative Fuels Development Unit (AFDU). The program will involve a continuation of the work performed under the Alternative Fuels from Coal-Derived Synthesis Gas Program and will draw upon information and technologies generated in parallel current and future DOE-funded contracts.

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

    DOEpatents

    Dyer, Paul N.; Pierantozzi, Ronald

    1986-01-01

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

  9. CO/sub 2/ removal from ammonia synthesis gas with SELEXOL Solvent Process

    SciTech Connect

    Shah, V.A.

    1987-01-01

    The high cost of energy which has prevailed since the 70's has forced ammonia producers to seek new methods to save energy and lower the ammonia production cost. The purpose of this paper is to discuss the use of SELEXOL Solvent Process for treatment of ammonia synthesis gas and discuss a patented SELEXOL process scheme which permits substantially 100% carbon dioxide recovery. This paper also describes: the SELEXOL Process Technology; treating of Ammonia Synthesis Gas; philosophy; high CO/sub 2/ Recovery Process; 100% CO2 Recovery Process; cost and Utility Requirement; plant Performance Data.

  10. High pressure synthesis gas fermentation, January 15, 1991--April 14,1991

    SciTech Connect

    Not Available

    1991-01-01

    The components of synthesis gas can be converted into ethanol by the bacterium Clostridium ljunfdahlii, Strain PETC. This microorganism achieves complete conversion of synthesis gas and gives stoichiometric yields of ethanol with high energy efficiency. The reaction rate and bioreactor size are the controlling factors in the commercialization of this process.Synthesis gas fermentations are mass transfer limited due to the very low gas solubilities. It has been demonstrated that reaction rate is proportional to pressure at least up to 10 atm, the limit of existing experimental equipment. The equivalent retention time at 10 atm can be reduced to three minutes. It is felt that retention times of a few seconds are possible and can be demonstrated at higher pressures. With such short equivalent reaction times, the reactor volume for large scale alcohol production becomes nominal and commercial application is assured. The objective of this project is to construct and test a high pressure fermentation system for the production of ethanol from synthesis gas. This system will be fabricated and assembled and the unit used to define the effects of elevated pressure on the growth and performance of C. ljungdahlii. The limits of cell concentration and mass transport relationships will be found in immobilized cell and stirred tank reactors. Minimum retention times and reactor volumes will be found for ethanol production in these reactors.

  11. High pressure synthesis gas fermentation, January 15, 1991--April 14,1991

    SciTech Connect

    Not Available

    1991-12-31

    The components of synthesis gas can be converted into ethanol by the bacterium Clostridium ljunfdahlii, Strain PETC. This microorganism achieves complete conversion of synthesis gas and gives stoichiometric yields of ethanol with high energy efficiency. The reaction rate and bioreactor size are the controlling factors in the commercialization of this process.Synthesis gas fermentations are mass transfer limited due to the very low gas solubilities. It has been demonstrated that reaction rate is proportional to pressure at least up to 10 atm, the limit of existing experimental equipment. The equivalent retention time at 10 atm can be reduced to three minutes. It is felt that retention times of a few seconds are possible and can be demonstrated at higher pressures. With such short equivalent reaction times, the reactor volume for large scale alcohol production becomes nominal and commercial application is assured. The objective of this project is to construct and test a high pressure fermentation system for the production of ethanol from synthesis gas. This system will be fabricated and assembled and the unit used to define the effects of elevated pressure on the growth and performance of C. ljungdahlii. The limits of cell concentration and mass transport relationships will be found in immobilized cell and stirred tank reactors. Minimum retention times and reactor volumes will be found for ethanol production in these reactors.

  12. Direct Routes from Synthesis Gas to Ethylene Glycol.

    ERIC Educational Resources Information Center

    Dombek, B. D.

    1986-01-01

    Discusses the synthesis of ethylene glycol from carbon monoxide and hydrogen using bimetallic catalysts. Although this technology has not been implemented, it illustrates two important future trends, namely, use of bimetallic catalysts and use of coal-derived carbon monoxide and hydrogen as a new feed stock. (JN)

  13. Microemulsion impregnated catalyst composite and use thereof in a synthesis gas conversion process

    DOEpatents

    Abrevaya, Hayim; Targos, William M.

    1987-01-01

    A catalyst composition for synthesis gas conversion comprising a ruthenium metal component deposited on a support carrier wherein the average metal particle size is less than about 100 A. The method of manufacture of the composition via a reverse micelle impregnation technique and the use of the composition in a Fischer-Tropsch conversion process is also disclosed.

  14. Microemulsion impregnated catalyst composite and use thereof in a synthesis gas conversion process

    DOEpatents

    Abrevaya, H.; Targos, W.M.

    1987-12-22

    A catalyst composition is described for synthesis gas conversion comprising a ruthenium metal component deposited on a support carrier wherein the average metal particle size is less than about 100 A. The method of manufacture of the composition via a reverse micelle impregnation technique and the use of the composition in a Fischer-Tropsch conversion process is also disclosed.

  15. Alternate fuels and chemicals from synthesis gas: Vinyl acetate monomer. Final report

    SciTech Connect

    Richard D. Colberg; Nick A. Collins; Edwin F. Holcombe; Gerald C. Tustin; Joseph R. Zoeller

    1999-01-01

    There has been a long-standing desire on the part of industry and the U.S. Department of Energy to replace the existing ethylene-based vinyl acetate monomer (VAM) process with an entirely synthesis gas-based process. Although there are a large number of process options for the conversion of synthesis gas to VAM, Eastman Chemical Company undertook an analytical approach, based on known chemical and economic principles, to reduce the potential candidate processes to a select group of eight processes. The critical technologies that would be required for these routes were: (1) the esterification of acetaldehyde (AcH) with ketene to generate VAM, (2) the hydrogenation of ketene to acetaldehyde, (3) the hydrogenation of acetic acid to acetaldehyde, and (4) the reductive carbonylation of methanol to acetaldehyde. This report describes the selection process for the candidate processes, the successful development of the key technologies, and the economic assessments for the preferred routes. In addition, improvements in the conversion of acetic anhydride and acetaldehyde to VAM are discussed. The conclusion from this study is that, with the technology developed in this study, VAM may be produced from synthesis gas, but the cost of production is about 15% higher than the conventional oxidative acetoxylation of ethylene, primarily due to higher capital associated with the synthesis gas-based processes.

  16. Design, Synthesis, and Mechanistic Evaluation of Iron-Based Catalysis for Synthesis Gas Conversion to Fuels and Chemicals

    SciTech Connect

    Enrique Iglesia

    2004-09-30

    This project explores the extension of previously discovered Fe-based catalysts with unprecedented Fischer-Tropsch synthesis rate, selectivity, and ability to convert hydrogen-poor synthesis gas streams typical of those produced from coal and biomass sources. Contract negotiations were completed on December 9, 2004. During the first reporting period, we certified a microreactor, installed required analytical equipment, and reproduced synthetic protocols and catalytic performance previously reported. During this second reporting period, we have prepared and tested several Fe-based compositions for Fischer-Tropsch synthesis and tested the effects of product recycle under both subcritical and supercritical conditions. These studies established modest improvements in rates and selectivities with light hydrocarbon recycle without any observed deleterious effects, opening up the opportunities for using of recycle strategies to control temperature profiles in fixed-bed Fe-based Fischer-Tropsch synthesis reactors without any detectable kinetic detriment. In a parallel study, we examined similar effects of recycle for cobalt-based catalysts; marked selectivity improvements were observed as a result of the removal of significant transport restrictions on these catalysts. Finally, we have re-examined some previously unanalyzed data dealing with the mechanism of the Fischer-Tropsch synthesis, specifically kinetic isotope effects on the rate and selectivity of chain growth reactions on Fe-based catalysts.

  17. Oxygen transport membrane based advanced power cycle with low pressure synthesis gas slip stream

    DOEpatents

    Kromer, Brian R.; Litwin, Michael M.; Kelly, Sean M.

    2016-09-27

    A method and system for generating electrical power in which a high pressure synthesis gas stream generated in a gasifier is partially oxidized in an oxygen transport membrane based reactor, expanded and thereafter, is combusted in an oxygen transport membrane based boiler. A low pressure synthesis gas slip stream is split off downstream of the expanders and used as the source of fuel in the oxygen transport membrane based partial oxidation reactors to allow the oxygen transport membrane to operate at low fuel pressures with high fuel utilization. The combustion within the boiler generates heat to raise steam to in turn generate electricity by a generator coupled to a steam turbine. The resultant flue gas can be purified to produce a carbon dioxide product.

  18. Natural synthesis of bioactive greigite by solid-gas reactions

    NASA Astrophysics Data System (ADS)

    Igarashi, Kensuke; Yamamura, Yasuhisa; Kuwabara, Tomohiko

    2016-10-01

    Greigite, a ferrimagnetic iron sulfide Fe(II)Fe(III)2S4, is thought to have played an essential role in chemical evolution leading to the origin of life. Greigite contains a [4Fe-4S] cluster-like structure and has been synthesized in the laboratory by liquid-state reactions. However, it is unclear how greigite can be synthesized in nature. Herein, we show that greigite is synthesized by the solid-gas reaction of Fe(III)-oxide-hydroxides and H2S. We discovered that the hyperthermophilic hydrogenotrophic methanogen Methanocaldococcus jannaschii reduced elemental sulfur, and the resulting sulfide generated greigite from hematite. The time course and pH dependence of the reaction respectively indicated the involvement of amorphous FeS and H2S as reaction intermediates. An abiotic solid-gas reaction of hematite and H2S (g) under strictly anaerobic conditions was developed. The solid-gas reaction fully converted hematite to greigite/pyrite at 40-120 °C within 12 h and was unaffected by the bulk gas phase. Similar abiotic reactions occurred, but relatively slowly, with aqueous H2S in acidulous liquids using hematite, magnetite, or amorphous FeO(OH) as starting materials, suggesting that greigite was extensively produced in the Hadean Eon as these Fe(III)-oxide-hydroxides were shown to be present or routinely produced during that era. Surprisingly, the obtained greigite induced methanogenesis and growth of hydrogenotrophic methanogens, suggesting that the external greigite crystals enhanced reactions that would otherwise require enzymes, such as [4Fe-4S] cluster-harboring membrane-bound hydrogenases. These data suggested that the greigite produced by the solid-gas and solid-dissolved gas reactions was bioactive.

  19. Sorbents for High Temperature Removal of Arsenic from Coal-Derived Synthesis Gas

    SciTech Connect

    Alptekin, G.O.; Copeland, R.; Dubovik, M.; Gershanovich, Y.

    2002-09-20

    Gasification technologies convert coal and other heavy feedstocks into synthesis gas feed streams that can be used in the production of a wide variety of chemicals, ranging from hydrogen through methanol, ammonia, acetic anhydride, dimethyl ether (DME), methyl tertiary butyl ether (MTBE), high molecular weight liquid hydrocarbons and waxes. Syngas can also be burned directly as a fuel in advanced power cycles to generate electricity with very high efficiency. However, the coal-derived synthesis gas contains a myriad of trace contaminants that may poison the catalysts that are used in the downstream manufacturing processes and may also be regulated in power plant emissions. Particularly, the catalysts used in the conversion of synthesis gas to methanol and other liquid fuels (Fischer-Tropsch liquids) have been found to be very sensitive to the low levels of poisons, especially arsenic, that are present in the synthesis gas from coal. TDA Research, Inc. (TDA) is developing an expendable high capacity, low-cost chemical absorbent to remove arsenic from coal-derived syngas. Unlike most of the commercially available sorbents that physically adsorb arsenic, TDA's sorbent operates at elevated temperatures and removes the arsenic through chemical reaction. The arsenic content in the coal gas stream is reduced to ppb levels with the sorbent by capturing and stabilizing the arsenic gas (As4) and arsenic hydrides (referred to as arsine, AsH3) in the solid state. To demonstrate the concept of high temperature arsenic removal from coal-derived syngas, we carried out bench-scale experiments to test the absorption capacity of a variety of sorbent formulations under representative conditions. Using on-line analysis techniques, we monitored the pre- and post-breakthrough arsine concentrations over different sorbent samples. Some of these samples exhibited pre-breakthrough arsine absorption capacity over 40% wt. (capacity is defined as lb of arsenic absorbed/lb of sorbent), while

  20. Design, Synthesis, and Mechanistic Evaluation of Iron-Based Catalysis for Synthesis Gas Conversion to Fuels and Chemicals

    SciTech Connect

    Akio Ishikawa; Manuel Ojeda; Nan Yao; Enrique Iglesia

    2006-03-31

    This project extends previously discovered Fe-based catalysts to hydrogen-poor synthesis gas streams derived from coal and biomass sources. These catalysts have shown unprecedented Fischer-Tropsch synthesis rate, selectivity for feedstocks consisting of synthesis gas derived from methane. During the first reporting period, we certified a microreactor, installed required analytical equipment, and reproduced synthetic protocols and catalytic results previously reported. During the second reporting period, we prepared several Fe-based compositions for Fischer-Tropsch synthesis and tested the effects of product recycle under both subcritical and supercritical conditions. During the third and fourth reporting periods, we improved the catalysts preparation method, which led to Fe-based FT catalysts with the highest FTS reaction rates and selectivities so far reported, a finding that allowed their operation at lower temperatures and pressures with high selectivity to desired products (C{sub 5+}, olefins). During this fifth reporting period, we have studied the effects of different promoters on catalytic performance, specifically how their sequence of addition dramatically influences the performance of these materials in the Fischer-Tropsch synthesis. The resulting procedures have been optimized to improve further upon the already unprecedented rates and C{sub 5+} selectivities of the Fe-based catalysts that we have developed as part of this project. During this fifth reporting period, we have also continued our studies of optimal activation procedures, involving reduction and carburization of oxide precursors during the early stages of contact with synthesis gas. We have completed the analysis of the evolution of oxide, carbide, and metal phases of the active iron components during initial contact with synthesis gas using advanced synchrotron techniques based on X-ray absorption spectroscopy. We have confirmed that the Cu or Ru compensates for inhibitory effects of Zn, a

  1. Nanocasting synthesis and gas-sensing behavior of hematite nanowires

    NASA Astrophysics Data System (ADS)

    Li, Danping; Zhang, Y.; Xu, Jingcai; Jin, Hongxiao; Jin, Dingfeng; Hong, Bo; Peng, Xiaoling; Wang, Panfeng; Ge, Hongliang; Wang, Xinqing

    2016-10-01

    The dispersed and uniform hematite nanowires (α-Fe2O3 NWs) with the different diameter were synthesized using SBA-15 as hard templates by the nanocasting method, and the diameter of α-Fe2O3 NWs was about 4, 6 and 8 nm, respectively. The BET surface area of α-Fe2O3 NWs changed a little, while the bandgap decreased from 2.07, 2.03 to 1.91 eV with the increasing diameter according to quantum size effect. Compared all samples, the sensitivity of α-Fe2O3 NWs based gas-sensors increased from 10.64 to 11.43 with the bandgap and BET surface area α-Fe2O3 NWs in 100 ppm ethanol at 300 °C, and the response-recovery time was also improved for the good crystallinity. It's concluded that the surface area greatly affected the gas-sensing performance of α-Fe2O3 NWs based sensors, while the bandgap and crystallinity also influenced the gas-sensing behavior to some extent. The α-Fe2O3 NWs based gas-sensors exhibited the high sensitivity, fast response-recovery and good selectivity to ethanol.

  2. Electrochemical polishing of hydrogen sulfide from coal synthesis gas

    SciTech Connect

    Gleason, E.F.; Winnick, J.

    1995-11-01

    An advanced process has been developed for the separation of H{sub 2}S from coal gasification product streams through an electrochemical membrane. This technology is developed for use in coal gasification facilities providing fuel for cogeneration coal fired electrical power facilities and Molten Carbonate Fuel Cell electrical power facilities. H{sub 2}S is removed from the syn-gas by reduction to the sulfide ion and H at the cathode. The sulfide ion migrates to the anode through a molten salt electrolyte suspended in an inert ceramic matrix. Once at the anode it is oxidized to elemental sulfur and swept away for condensation in an inert gas stream. The syn-gas is enriched with the H{sub 2}. Order-of-magnitude reductions in H{sub 2}S have been repeatably recorded (100 ppm to 10 ppm H{sub 2}S) on a single pass through the cell. This process allows removal of H{sub 2}S without cooling the gas stream and with negligible pressure loss through the separator. Since there are no absorbents used, there is no absorption/regeneration step as with conventional technology. Elemental sulfur is produced as a by-product directly, so there is no need for a Claus process for sulfur recovery. This makes the process economically attractive since it is much less equipment intensive than conventional technology.

  3. DESIGN, SYNTHESIS, AND MECHANISTIC EVALUATION OF IRON-BASED CATALYSIS FOR SYNTHESIS GAS CONVERSION TO FUELS AND CHEMICALS

    SciTech Connect

    Akio Ishikawa; Manuel Ojeda; Enrique Iglesia

    2005-03-31

    This project explores the extension of previously discovered Fe-based catalysts to hydrogen-poor synthesis gas streams derived from coal and biomass sources. These catalysts have previously shown unprecedented Fischer-Tropsch synthesis rate, selectivity with synthesis gas derived from methane. During the first reporting period, we certified a microreactor, installed required analytical equipment, and reproduced synthetic protocols and catalytic performance previously reported. During the second reporting period, we prepared several Fe-based compositions for Fischer-Tropsch synthesis and tested the effects of product recycle under both subcritical and supercritical conditions. During this third reporting period, we have prepared a large number of Fe-based catalyst compositions using precipitation and impregnations methods with both supercritical and subcritical drying and with the systematic use of surface active agents to prevent pore collapse during drying steps required in synthetic protocols. These samples were characterized during this period using X-ray diffraction, surface area, and temperature-programmed reduction measurements. These studies have shown that these synthesis methods lead to even higher surface areas than in our previous studies and confirm the crystalline structures of these materials and their reactivity in both oxide-carbide interconversions and in Fischer-Tropsch synthesis catalysis. Fischer-Tropsch synthesis reaction rates and selectivities with low H{sub 2}/CO ratio feeds (H{sub 2}/CO = 1) were the highest reported in the literature at the low-temperature and relatively low pressure in our measurements. Current studies are exploring the optimization of the sequence of impregnation of Cu, K, and Ru promoters, of the activation and reaction conditions, and of the co-addition of light hydrocarbons to increase diffusion rates of primary olefin products so as to increase the selectivity to unsaturated products. Finally, we are also addressing

  4. Synthesis, pervaporation and gas separation studies of polyaniline blends

    SciTech Connect

    Huang, S.C.; Conklin, J.A.; Su, T.M.

    1995-12-01

    Membranes have been successfully produced from blends of polyaniline/polyacrylic acid and polyaniline/polyimide. The uniqueness of these membranes is the incorporation of {open_quotes}polymer dopants{close_quotes} in polyaniline. Conductivity measurements show that polyacrylic acid dopes the polyaniline. Pervaporation of water and water/acetic acid mixtures were performed using polyaniline and its polyacrylic acid blend. An improved flux over the polyaniline base form is observed. Polyaniline/polyimide blends were synthesized for gas permeability studies. These blends combine improved thermal stability relative to polyaniline with greater gas selectivity relative to polyimide. The blend shows an increase in permeability for all gases studied over both, polyaniline base and polyimide, while maintaining comparable separation factors.

  5. Synthesis gas and olefins from the catalytic autothermal reforming of volatile and non-volatile liquids

    NASA Astrophysics Data System (ADS)

    Dreyer, Bradon Justin

    2007-12-01

    The research presented in this thesis develops an understanding of a clean energy process technology, catalytic partial oxidation (CPO). CPO is a process in which a carbon containing fuel, such as a hydrocarbon, is passed over a noble metal catalyst (e.g. rhodium and platinum) to efficiently generate synthesis gas (H2 and CO) and olefins (e.g. ethylene and propylene) in millisecond contact times. Chapter 1 introduces CPO and compares this technology with conventional methods for synthesis gas and olefin production. CPO has several advantages over the traditional synthesis gas and olefin production methods. One advantage includes autothermal operation, requiring no external heat input from furnaces or heat exchangers. Autothermal operation allows these reactors to be built compactly. The short contact-times associated with CPO further enable for high throughput in relatively small reactor systems, and more compact reactors typically translate to faster response times if transient operation is required. Nobel metal based CPO catalysts are also resistant to deactivation, resulting in less catalyst replacement, regeneration, and maintenance, and an increase in operating efficiency. An overview of the many applications of the chemicals produced from CPO is also presented in Chapter 1. The chemicals produced are crucial in generating valuable chemical intermediates that are eventually incorporated in consumer products, medical devices, building structures, and fertilizers. Additionally, H2 can be used as a source of energy in mobile fuel applications. Fuel cells convert H2 and O2 into electricity and water at higher efficiencies than thermal engine generators. Due to the difficulties in H2 storage, these more efficient energy generators are dependent on hydrogen obtained from synthesis gas production in compact, portable fuel reformers, such as CPO reactors. Furthermore, H2 and CO can be used in reducing environmentally harmful emissions. Particularly, the implementation

  6. New iron catalyst for preparation of polymethylene from synthesis gas

    DOEpatents

    Sapienza, R.S.; Slegeir, W.A.

    1988-03-31

    This invention relates to a process for synthesizing hydrocarbons; more particularly, the invention relates to a process for synthesizing long-chain hydrocarbons known as polymethylene from carbon monoxide and hydrogen or from carbon monoxide and water or mixtures thereof in the presence of a catalyst comprising iron and platinum or palladium or mixtures thereof which may be supported on a solid material, preferably an inorganic refractory oxide. This process may be used to convert a carbon monoxide containing gas to a product which could substitute for high density polyethylene.

  7. Iron catalyst for preparation of polymethylene from synthesis gas

    DOEpatents

    Sapienza, Richard S.; Slegeir, William A.

    1990-01-01

    This invention relates to a process for synthesizing hydrocarbons; more particularly, the invention relates to a process for synthesizing long-chain hydrocarbons known as polymethylene from carbon monoxide and hydrogen or from carbon monoxide and water or mixtures thereof in the presence of a catalyst comprising iron and platinum or palladium or mixtures thereof which may be supported on a solid material, preferably an inorganic refractory oxide. This process may be used to convert a cabon monoxide containing gas to a product which could substitute for high density polyethylene.

  8. Multiscale Aspects of Modeling Gas-Phase Nanoparticle Synthesis

    PubMed Central

    Buesser, B.; Gröhn, A.J.

    2013-01-01

    Aerosol reactors are utilized to manufacture nanoparticles in industrially relevant quantities. The development, understanding and scale-up of aerosol reactors can be facilitated with models and computer simulations. This review aims to provide an overview of recent developments of models and simulations and discuss their interconnection in a multiscale approach. A short introduction of the various aerosol reactor types and gas-phase particle dynamics is presented as a background for the later discussion of the models and simulations. Models are presented with decreasing time and length scales in sections on continuum, mesoscale, molecular dynamics and quantum mechanics models. PMID:23729992

  9. Process and catalyst for converting synthesis gas to liquid hydrocarbon mixture

    DOEpatents

    Rao, V. Udaya S.; Gormley, Robert J.

    1987-01-01

    Synthesis gas containing CO and H.sub.2 is converted to a high-octane hydrocarbon liquid in the gasoline boiling point range by bringing the gas into contact with a heterogeneous catalyst including, in physical mixture, a zeolite molecular sieve, cobalt at 6-20% by weight, and thoria at 0.5-3.9% by weight. The contacting occurs at a temperature of 250.degree.-300.degree. C., and a pressure of 10-30 atmospheres. The conditions can be selected to form a major portion of the hydrocarbon product in the gasoline boiling range with a research octane of more than 80 and less than 10% by weight aromatics.

  10. Fischer Indole Synthesis in the Gas Phase, the Solution Phase, and at the Electrospray Droplet Interface

    NASA Astrophysics Data System (ADS)

    Bain, Ryan M.; Ayrton, Stephen T.; Cooks, R. Graham

    2017-02-01

    Previous reports have shown that reactions occurring in the microdroplets formed during electrospray ionization can, under the right conditions, exhibit significantly greater rates than the corresponding bulk solution-phase reactions. The observed acceleration under electrospray ionization could result from a solution-phase, a gas-phase, or an interfacial reaction. This study shows that a gas-phase ion/molecule (or ion/ion) reaction is not responsible for the observed rate enhancement in the particular case of the Fischer indole synthesis. The results show that the accelerated reaction proceeds in the microdroplets, and evidence is provided that an interfacial process is involved.

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

    PubMed

    Kim, Daehee; Chang, In Seop

    2009-10-01

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

  12. Impact of Contaminants Present in Coal-Biomass Derived Synthesis Gas on Water-gas Shift and Fischer-Tropsch Synthesis Catalysts

    SciTech Connect

    Alptekin, Gokhan

    2013-02-15

    Co-gasification of biomass and coal in large-scale, Integrated Gasification Combined Cycle (IGCC) plants increases the efficiency and reduces the environmental impact of making synthesis gas ("syngas") that can be used in Coal-Biomass-to-Liquids (CBTL) processes for producing transportation fuels. However, the water-gas shift (WGS) and Fischer-Tropsch synthesis (FTS) catalysts used in these processes may be poisoned by multiple contaminants found in coal-biomass derived syngas; sulfur species, trace toxic metals, halides, nitrogen species, the vapors of alkali metals and their salts (e.g., KCl and NaCl), ammonia, and phosphorous. Thus, it is essential to develop a fundamental understanding of poisoning/inhibition mechanisms before investing in the development of any costly mitigation technologies. We therefore investigated the impact of potential contaminants (H2S, NH3, HCN, AsH3, PH3, HCl, NaCl, KCl, AS3, NH4NO3, NH4OH, KNO3, HBr, HF, and HNO3) on the performance and lifetime of commercially available and generic (prepared in-house) WGS and FT catalysts.

  13. Method for forming synthesis gas using a plasma-catalyzed fuel reformer

    DOEpatents

    Hartvigsen, Joseph J; Elangovan, S; Czernichowski, Piotr; Hollist, Michele

    2015-04-28

    A method of forming a synthesis gas utilizing a reformer is disclosed. The method utilizes a reformer that includes a plasma zone to receive a pre-heated mixture of reactants and ionize the reactants by applying an electrical potential thereto. A first thermally conductive surface surrounds the plasma zone and is configured to transfer heat from an external heat source into the plasma zone. The reformer further includes a reaction zone to chemically transform the ionized reactants into synthesis gas comprising hydrogen and carbon monoxide. A second thermally conductive surface surrounds the reaction zone and is configured to transfer heat from the external heat source into the reaction zone. The first thermally conductive surface and second thermally conductive surface are both directly exposed to the external heat source. A corresponding apparatus and system are also disclosed herein.

  14. Wet Chemical Synthesis and Screening of Thick Porous Oxide Films for Resistive Gas Sensing Applications

    PubMed Central

    Frenzer, Gerald; Frantzen, Andreas; Sanders, Daniel; Simon, Ulrich; Maier, Wilhelm F.

    2006-01-01

    A method of wet chemical synthesis suitable for high throughput and combinatorial applications has been developed for the synthesis of porous resistive thick-film gas sensors. This method is based on the robot-controlled application of unstable metal oxide suspensions on an array of 64 inter-digital electrodes positioned on an Al2O3 substrate. SnO2, WO3, ZrO2, TiO2, CeO2, In2O3 and Bi2O3 were chosen as base oxides, and were optimised by doping or mixed oxide formation. The parallel synthesis of mixed oxide sensors is illustrated by representative examples. The electrical characteristics and the sensor performance of the films were measured by high-throughput impedance spectroscopy while supplying various test gases (H2, CO, NO, NO2, propene). Data collection, data mining techniques applied and the best potential sensor materials discovered are presented.

  15. Harnessing the Power of the Water-Gas Shift Reaction for Organic Synthesis.

    PubMed

    Ambrosi, Andrea; Denmark, Scott E

    2016-09-26

    Since its original discovery over a century ago, the water-gas shift reaction (WGSR) has played a crucial role in industrial chemistry, providing a source of H2 to feed fundamental industrial transformations such as the Haber-Bosch synthesis of ammonia. Although the production of hydrogen remains nowadays the major application of the WGSR, the advent of homogeneous catalysis in the 1970s marked the beginning of a synergy between WGSR and organic chemistry. Thus, the reducing power provided by the CO/H2 O couple has been exploited in the synthesis of fine chemicals; not only hydrogenation-type reactions, but also catalytic processes that require a reductive step for the turnover of the catalytic cycle. Despite the potential and unique features of the WGSR, its applications in organic synthesis remain largely underdeveloped. The topic will be critically reviewed herein, with the expectation that an increased awareness may stimulate new, creative work in the area.

  16. Catalyst and process for converting synthesis gas to liquid motor fuels

    DOEpatents

    Coughlin, Peter K.

    1987-01-01

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

  17. Design, Synthesis and Mechanistic Evaluation of Iron-Based Catalysis for Synthesis Gas Conversion to Fuels and Chemicals

    SciTech Connect

    Akio Ishikawa; Manuel Ojeda; Nan Yao; Enrique Iglesia

    2007-03-31

    This project extends previously discovered Fe-based catalysts to hydrogen-poor synthesis gas streams derived from coal and biomass sources. These catalysts have shown unprecedented Fischer-Tropsch synthesis rates and selectivities for synthesis gas derived from methane. During the first reporting period, we certified a microreactor, installed required analytical equipment, and reproduced synthetic protocols and catalytic results previously reported. During the second reporting period, we prepared several Fe-based compositions for Fischer-Tropsch Synthesis and tested the effects of product recycle under both subcritical and supercritical conditions. During the third and fourth reporting periods, we improved the catalysts preparation method, which led to Fe-based materials with the highest FTS reaction rates and selectivities so far reported, a finding that allowed their operation at lower temperatures and pressures with high selectivity to desired products (C{sub 5+}, olefins). During the fifth and sixth reporting period, we studied the effects of different promoters on catalytic performance, specifically how their sequence of addition dramatically influenced the performance of these materials in the Fischer-Tropsch synthesis. We also continued our studies of the kinetic behavior of these materials during the sixth reporting period. Specifically, the effects of H{sub 2}, CO, and CO{sub 2} on the rates and selectivities of Fischer-Tropsch Synthesis reactions led us to propose a new sequence of elementary steps on Fe and Co Fischer-Tropsch catalysts. Finally, we also started a study of the use of colloidal precipitation methods for the synthesis small Co clusters using recently developed methods to explore possible further improvements in FTS rates and selectivities. We found that colloidal synthesis makes possible the preparation of small cobalt particles, although large amount of cobalt silicate species, which are difficult to reduce, were formed. During this

  18. Design, Synthesis, and Mechanistic Evaluation of Iron-Based Catalysis for Synthesis Gas Conversion to Fuels and Chemicals

    SciTech Connect

    Akio; Ishikawa; Manuel Ojeda; Nan Yao; Enrique Iglesia

    2006-09-30

    This project extends previously discovered Fe-based catalysts to hydrogen-poor synthesis gas streams derived from coal and biomass sources. These catalysts have shown unprecedented Fischer-Tropsch synthesis rates and selectivities for feedstocks consisting of synthesis gas derived from methane. During the first reporting period, we certified a microreactor, installed required analytical equipment, and reproduced synthetic protocols and catalytic results previously reported. During the second reporting period, we prepared several Fe-based compositions for Fischer-Tropsch Synthesis and tested the effects of product recycle under both subcritical and supercritical conditions. During the third and fourth reporting periods, we improved the catalysts preparation method, which led to Fe-based FT catalysts with the highest FTS reaction rates and selectivities so far reported, a finding that allowed their operation at lower temperatures and pressures with high selectivity to desired products (C{sub 5+}, olefins). During the fifth reporting period, we studied the effects of different promoters on catalytic performance, specifically how their sequence of addition dramatically influenced the performance of these materials in the Fischer-Tropsch synthesis. We also continued our studies of the kinetic behavior of these materials. Specifically, the effects of H{sub 2}, CO, and CO{sub 2} on the rates and selectivities of Fischer-Tropsch Synthesis reactions led us to propose a new sequence of elementary steps on Fe and Co Fischer-Tropsch catalysts. More specifically, we were focused on the roles of hydrogen-assisted and alkali-assisted dissociation of CO in determining rates and CO{sub 2} selectivities. During this sixth reporting period, we have studied the validity of the mechanism that we propose by analyzing the H{sub 2}/D{sub 2} kinetic isotope effect (r{sub H}/r{sub D}) over a conventional iron-based Fischer-Tropsch catalyst Fe-Zn-K-Cu. We have observed experimentally that

  19. Synthesis and Gas Phase Thermochemistry of Germanium-Containing Compounds

    SciTech Connect

    Classen, Nathan Robert

    2002-01-01

    The driving force behind much of the work in this dissertation was to gain further understanding of the unique olefin to carbene isomerization observed in the thermolysis of 1,1-dimethyl-2-methylenesilacyclobutane by finding new examples of it in other silicon and germanium compounds. This lead to the examination of a novel phenylmethylenesilacyclobut-2-ene, which did not undergo olefin to carbene rearrangement. A synthetic route to methylenegermacyclobutanes was developed, but the methylenegermacyclobutane system exhibited kinetic instability, making the study of the system difficult. In any case the germanium system decomposed through a complex mechanism which may not include olefin to carbene isomerization. However, this work lead to the study of the gas phase thermochemistry of a series of dialkylgermylene precursors in order to better understand the mechanism of the thermal decomposition of dialkylgermylenes. The resulting dialkylgermylenes were found to undergo a reversible intramolecular β C-H insertion mechanism.

  20. Removal of Mercury from Coal-Derived Synthesis Gas

    SciTech Connect

    2005-09-29

    A paper study was completed to survey literature, patents, and companies for mercury removal technologies applicable to gasification technologies. The objective was to determine if mercury emissions from gasification of coal are more or less difficult to manage than those from a combustion system. The purpose of the study was to define the extent of the mercury problem for gasification-based coal utilization and conversion systems. It is clear that in coal combustion systems, the speciation of mercury between elemental vapor and oxidized forms depends on a number of factors. The most important speciation factors are the concentration of chlorides in the coal, the temperatures in the ducting, and residence times. The collection of all the mercury was most dependent upon the extent of carbon in the fly ash, and the presence of a wet gas desulfurization system. In combustion, high chloride content plus long residence times at intermediate temperatures leads to oxidation of the mercury. The mercury is then captured in the wet gas desulfurization system and in the fly ash as HgCl{sub 2}. Without chloride, the mercury oxidizes much slower, but still may be trapped on thick bag house deposits. Addition of limestone to remove sulfur may trap additional mercury in the slag. In gasification where the mercury is expected to be elemental, activated carbon injection has been the most effective method of mercury removal. The carbon is best injected downstream where temperatures have moderated and an independent collector can be established. Concentrations of mercury sorbent need to be 10,000 to 20,000 the concentrations of the mercury. Pretreatment of the activated carbon may include acidification or promotion by sulfur.

  1. Design and synthesis of copper-cobalt catalysts for the selective conversion of synthesis gas to ethanol and higher alcohols.

    PubMed

    Prieto, Gonzalo; Beijer, Steven; Smith, Miranda L; He, Ming; Au, Yuen; Wang, Zi; Bruce, David A; de Jong, Krijn P; Spivey, James J; de Jongh, Petra E

    2014-06-16

    Combining quantum-mechanical simulations and synthesis tools allows the design of highly efficient CuCo/MoO(x) catalysts for the selective conversion of synthesis gas (CO+H2) into ethanol and higher alcohols, which are of eminent interest for the production of platform chemicals from non-petroleum feedstocks. Density functional theory calculations coupled to microkinetic models identify mixed Cu-Co alloy sites, at Co-enriched surfaces, as ideal for the selective production of long-chain alcohols. Accordingly, a versatile synthesis route is developed based on metal nanoparticle exsolution from a molybdate precursor compound whose crystalline structure isomorphically accommodates Cu(2+) and Co(2+) cations in a wide range of compositions. As revealed by energy-dispersive X-ray nanospectroscopy and temperature-resolved X-ray diffraction, superior mixing of Cu and Co species promotes formation of CuCo alloy nanocrystals after activation, leading to two orders of magnitude higher yield to high alcohols than a benchmark CuCoCr catalyst. Substantiating simulations, the yield to high alcohols is maximized in parallel to the CuCo alloy contribution, for Co-rich surface compositions, for which Cu phase segregation is prevented.

  2. Design, Synthesis, and Mechanistic Evaluation of Iron-Based Catalysis for Synthesis Gas Conversion to Fuels and Chemicals

    SciTech Connect

    Akio Ishikawa; Manuel Ojeda; Enrique Iglesia

    2005-09-30

    This project extends previously discovered Fe-based catalysts to hydrogen-poor synthesis gas streams derived from coal and biomass sources. These catalysts have shown unprecedented Fischer-Tropsch synthesis rate, selectivity for feedstocks consisting of synthesis gas derived from methane. During the first reporting period, we certified a microreactor, installed required analytical equipment, and reproduced synthetic protocols and catalytic results previously reported. During the second reporting period, we prepared several Fe-based compositions for Fischer-Tropsch synthesis and tested the effects of product recycle under both subcritical and supercritical conditions. During the third reporting period, we improved the catalysts preparation method, which led to Fe-based FT catalysts with the highest FTS reaction rates and selectivities so far reported, a finding that allowed their operation at lower temperatures and pressures with high selectivity to desired products (C{sub 5+}, olefins). During this fourth reporting period, we have determined the effects of different promoters on catalytic performance. More specifically, we have found that the sequence in which promoters are introduced has a marked positive impact on rates and selectivities. Cu or Ru chemical promoters should be impregnated before K to achieve higher Fischer-Tropsch synthesis rates. The catalyst prepared in this way was evaluated for 240 h, showing a high catalytic activity and stability after an initial period of time necessary for the formation of the active phases. Concurrently, we are studying optimal activation procedures, which involve the reduction and carburization of oxide precursors during the early stages of contact with synthesis gas. Activation at low temperatures (523 K), made possible by optimal introduction of Cu or Ru, leads to lower catalyst surface area than higher activation temperatures, but to higher reaction rates, because such low temperatures avoid concurrent deactivation

  3. Biological conversion of synthesis gas. Mass transfer/kinetic studies

    SciTech Connect

    Klasson, K.T.; Basu, R.; Johnson, E.R.; Clausen, E.C.; Gaddy, J.L.

    1992-03-01

    Mass transfer and kinetic studies were carried out for the Rhodospirillum rubrum and Chlorobium thiosulfatophilum bacterial systems. R. rubrum is a photosynthetic anaerobic bacterium which catalyzes the biological water gas shift reaction: CO + H{sub 2}0 {yields} CO{sub 2} + H{sub 2}. C. thiosulfatophilum is also a H{sub 2}S and COS to elemental sulfur. The growth of R. rubrum may be satisfactorily carried out at 25{degree} and 30{degree}C, while CO uptake and thus the conversion of CO best occurs at temperatures of either 30{degree}, 32{degree} or 34{degree}C. The rate of conversion of COs and H{sub 2}O to CO{sub 2} and H{sub 2}S may be modeled by a first order rate expression. The rate constant at 30{degree}C was found to be 0.243 h{sup {minus}1}. The growth of C. thiosulfatophilum may be modeled in terms of incoming light intensity using a Monod equation: {mu} = {sub 351} + I{sub o}/{sup 0.152}I{sub o}. Comparisons of the growth of R. rubrum and C. thiosulfatophilum shows that the specific growth rate of C. thiosulfatophilum is much higher at a given light intensity.

  4. Gas phase laser synthesis and processing of calcium phosphate nanoparticles for biomedical applications

    NASA Astrophysics Data System (ADS)

    Bapat, Parimal V.

    Biochemical processes make pervasive use of calcium and phosphate ions. Calcium phosphate salts that are naturally nontoxic and bioactive have been used for several medical applications in form of coatings and micropowders. Nanoparticle-based calcium phosphates have been shown to be internalized by living cells and be effective in DNA transfection, drug delivery, and transport of fluorophores for imaging of intracellular processes. They are also expected to interact strongly with cell adhesive proteins and are therefore promising elements in approaches to mimic the complex environment of the extra cellular matrix of bone. Harnessing this biomedical potential requires the ability to control the numerous characteristics of nanophase calcium phosphates that affect biological response, including nanoparticle chemical composition, crystal phase, crystallinity, crystallographic orientation of exposed faces, size, shape, surface area, number concentration, and degree of aggregation. This dissertation focuses on the use of laser-induced gas-phase synthesis for creation of calcium phosphate nanoparticles, and corresponding nanoparticle-based substrates that could offer new opportunities for guiding biological responses through well-controlled biochemical and topological cues. Gas-phase synthesis of nanoparticles has several characteristics that could enhance control over particle morphology, crystallinity, and surface area, compared to liquid-phase techniques. Synthesis from gas-phase precursors can be carried out at high temperatures and in high-purity inert or reactive gas backgrounds, enabling good control of chemistry, crystal structure, and purity. Moreover, the particle mean free path and number concentration can be controlled independently. This allows regulation of interparticle collision rates, which can be adjusted to limit aggregation. High-temperature synthesis of well-separated particles is therefore possible. In this work high power lasers are employed to

  5. Bioconversion of coal-derived synthesis gas to liquid fuels. [Butyribacterium methylotrophicum

    SciTech Connect

    Jain, M.K.

    1991-01-01

    The use of coal-derived synthesis gas as an industrial feedstock for production of fuels and chemicals has become an increasingly attractive alternative to present petroleum-based chemicals production. However, one of the major limitations in developing such a process is the required removal of catalyst poisons such as hydrogen sulfide (H{sub 2}S), carbonyl sulfide (COS), and other trace contaminants from the synthesis gas. Purification steps necessary to remove these are energy intensive and add significantly to the production cost, particularly for coals having a high sulfur content such as Illinois coal. A two-stage, anaerobic bioconversion process requiring little or no sulfur removal is proposed, where in the first stage the carbon monoxide (CO) gas is converted to butyric and acetic acids by the CO strain of Butyribacterium methylotrophicum. In the second stage, these acids along with the hydrogen (H{sub 2}) gas are converted to butanol, ethanol, and acetone by an acid utilizing mutant of Clostridium acetobutylicum. 18 figs., 18 tabs.

  6. Synthesis of nanograined ZnO nanowires and their enhanced gas sensing properties.

    PubMed

    Park, Sunghoon; An, Soyeon; Ko, Hyunsung; Jin, Changhyun; Lee, Chongmu

    2012-07-25

    Polycrystalline ZnO nanowires with grain sizes ranging from 20 to 100 nm were synthesized using a newly designed two-step process: (first step) synthesis of ZnSe nanowires by vapor transportation of a mixture of ZnSe powders; and (second step) thermal oxidation of the ZnSe nanowires at 650 °C. Compared to the single-crystal ZnO nanowire gas sensors and other nanomaterial gas sensors reported previously, the multiple networked nanowire gas sensors fabricated from the nanograined ZnO nanowires showed substantially enhanced electrical responses to NO2 gas at 300 °C. The NO2 gas sensing properties of the nanograined ZnO nanowires increased dramatically with increasing NO2 concentration. The multiple-networked nanograined ZnO nanowire sensor showed a response value of 237,263% at 10 ppm NO2 and 300 °C, whereas the single-crystal ZnO nanowire sensors showed a response of only 6.5% under the same conditions. The recovery time of the nanograined ZnO nanowire sensor was much shorter than that of the normal ZnO nanowire sensor over the NO2 concentration range of 1-10 ppm, even though the response time of the former was somewhat longer than that of the latter. The origin of the enhanced NO2 gas sensing properties of the nanograined ZnO nanowire sensor is discussed.

  7. Synthesis and characterization of mixed matrix membranes for gas separation

    NASA Astrophysics Data System (ADS)

    Zhang, Yanfeng

    2007-12-01

    Mixed-matrix membranes were prepared from Matrimid RTM and mesoporous ZSM-5 nanoparticles containing crystalline ZSM-5. The mesoporous ZSM-5 has both micropores (0.54 nm) and mesopores (2.7 nm), which were confirmed by XRD, nitrogen adsorption, and TEM. The Young's moduli and glass transition temperatures of mixed-matrix membranes are higher than those of pure MatrimidRTM membranes, suggesting that the polymer chains may penetrate into the mesopores. The ideal selectivity for H2/N2 separation increased from 79.6 for pure Matrimid RTM to 143 at 10% loading, while the selectivity of O2/N 2 increased from 6.6 for pure MatrimidRTM to 10.4 at 20% loading. The ideal H2/CH4 separation factor increased from 83.3 to 169 at 20% loading. The results suggest that the mesopores of the ZSM-5 material can provide good interfacial contact between the nanoparticles and the polymer, since the polymer chains can penetrate into the mesopores. The micropores of ZSM-5 crystals can provide size and shape selectivity. A carbon aerogel was prepared by carbonizing a resorcinol-formaldehyde polymer gel at 800°C. Nitrogen adsorption shows the obtained carbon aerogel has both micropores (0.54 nm) and mesopores (2.14 nm). Zeolite A and zeolite Y nanocrystals were grown in the mesopores of the carbon aerogel, resulting in carbon aerogel-zeolite composites. TEM confirmed the existence of nanosize zeolite crystals in the carbon aerogel matrix. Higher selectivity for the CO2/CH4, O2/N2 and H2/N 2 separation were obtained for carbon aerogel-zeolite, carbon aerogel-zeolite-Matrimid RTM membranes. The small pore diameter of zeolite A and the affinity between the CO2 and zeolite crystals make it perfect for CO 2/CH4 separation. Short single-walled carbon nanotubes (SWNT) functionalized with carboxylic acid groups were made and incorporated into MatrimidRTM to form mixed-matrix membranes. SEM images of mixed-matrix membranes cross-sections showed good dispersion and interfacial contact. Pure gas

  8. Synthesis of refractory organic matter in the ionized gas phase of the solar nebula.

    PubMed

    Kuga, Maïa; Marty, Bernard; Marrocchi, Yves; Tissandier, Laurent

    2015-06-09

    In the nascent solar system, primitive organic matter was a major contributor of volatile elements to planetary bodies, and could have played a key role in the development of the biosphere. However, the origin of primitive organics is poorly understood. Most scenarios advocate cold synthesis in the interstellar medium or in the outer solar system. Here, we report the synthesis of solid organics under ionizing conditions in a plasma setup from gas mixtures (H2(O)-CO-N2-noble gases) reminiscent of the protosolar nebula composition. Ionization of the gas phase was achieved at temperatures up to 1,000 K. Synthesized solid compounds share chemical and structural features with chondritic organics, and noble gases trapped during the experiments reproduce the elemental and isotopic fractionations observed in primitive organics. These results strongly suggest that both the formation of chondritic refractory organics and the trapping of noble gases took place simultaneously in the ionized areas of the protoplanetary disk, via photon- and/or electron-driven reactions and processing. Thus, synthesis of primitive organics might not have required a cold environment and could have occurred anywhere the disk is ionized, including in its warm regions. This scenario also supports N2 photodissociation as the cause of the large nitrogen isotopic range in the solar system.

  9. Synthesis of refractory organic matter in the ionized gas phase of the solar nebula

    PubMed Central

    Kuga, Maïa; Marty, Bernard; Marrocchi, Yves; Tissandier, Laurent

    2015-01-01

    In the nascent solar system, primitive organic matter was a major contributor of volatile elements to planetary bodies, and could have played a key role in the development of the biosphere. However, the origin of primitive organics is poorly understood. Most scenarios advocate cold synthesis in the interstellar medium or in the outer solar system. Here, we report the synthesis of solid organics under ionizing conditions in a plasma setup from gas mixtures (H2(O)−CO−N2−noble gases) reminiscent of the protosolar nebula composition. Ionization of the gas phase was achieved at temperatures up to 1,000 K. Synthesized solid compounds share chemical and structural features with chondritic organics, and noble gases trapped during the experiments reproduce the elemental and isotopic fractionations observed in primitive organics. These results strongly suggest that both the formation of chondritic refractory organics and the trapping of noble gases took place simultaneously in the ionized areas of the protoplanetary disk, via photon- and/or electron-driven reactions and processing. Thus, synthesis of primitive organics might not have required a cold environment and could have occurred anywhere the disk is ionized, including in its warm regions. This scenario also supports N2 photodissociation as the cause of the large nitrogen isotopic range in the solar system. PMID:26039983

  10. Highly active and stable iron Fischer-Tropsch catalyst for synthesis gas conversion to liquid fuels

    SciTech Connect

    Bukur, D.B.; Lang, X.

    1999-09-01

    A precipitated iron Fischer-Tropsch (F-T) catalyst (100 Fe/3 Cu/4 K/16 SiO{sub 2} on mass basis) was tested in a stirred tank slurry reactor under reaction conditions representative of industrial practice using CO-rich synthesis gas (260 C, 1.5--2.2 MPa, H{sub 2}/CO = 2/3). Repeatability of performance and reproducibility of catalyst preparation procedure were successfully demonstrated on a laboratory scale. Catalyst productivity was increased by operating at higher synthesis pressure while maintaining a constant contact time in the reactor and through the use of different catalyst pretreatment procedures. In one of the tests (run SA-2186), the catalyst productivity was 0.86 (g hydrocarbons/g Fe/h) at syngas conversion of 79%, methane selectivity of 3% (weight percent of total hydrocarbons produced), and C{sub 5}+ hydrocarbon selectivity of 83 wt %. This represents a substantial improvement in productivity in comparison to state-of-the-art iron F-T catalysts. This catalyst is ideally suited for production of high-quality diesel fuels and C{sub 2}-c{sub 4} olefins from a coal-derived synthesis gas.

  11. High octane ethers from synthesis gas-derived alcohols. [Catalyst names: Amberlyst-15, BioRad AG 50WX2, Nafion-H microsaddles, and Purolite 150

    SciTech Connect

    Klier, K.; Herman, R.G.; Johannson, M.; Feeley, O.C.; Bogar, S.; Lawson, E.; Kieke, M.

    1991-11-01

    The objective of the proposed research is to synthesize high octane ethers, primarily methyl isobuty ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from H{sub 2}/CO/CO{sub 2} coal-derived synthesis gas via alcohol mixtures that are rich in methanol and 2-methyl-1-butanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers.

  12. Design, Synthesis, and Mechanistic Evaluation of Iron-Based Catalysis for Synthesis Gas Conversion to Fuels and Chemicals

    SciTech Connect

    Enrique Iglesia; Akio Ishikawa; Manual Ojeda; Nan Yao

    2007-09-30

    A detailed study of the catalyst composition, preparation and activation protocol of Fe-based catalysts for the Fischer-Tropsch Synthesis (FTS) have been carried out in this project. We have studied the effects of different promoters on the catalytic performance of Fe-based catalysts. Specifically, we have focused on how their sequence of addition dramatically influences the performance of these materials in the Fischer-Tropsch synthesis. The resulting procedures have been optimized to improve further upon the already unprecedented rates and C{sub 5+} selectivities of the Fe-based catalysts that we have developed as part of this project. Selectivity to C{sub 5+} hydrocarbon was close to 90 % (CO{sub 2}-free basis) and CO conversion rate was about 6.7 mol h{sup -1} g-at Fe{sup -1} at 2.14 MPa, 508 K and with substoichiometric synthesis gas; these rates were larger than any reported previously for Fe-based FTS catalysts at these conditions. We also tested the stability of Fe-based catalysts during FTS reaction (10 days); as a result, the high hydrocarbon formation rates were maintained during 10 days, though the gradual deactivation was observed. Our investigation has also focused on the evaluation of Fe-based catalysts with hydrogen-poor synthesis gas streams (H{sub 2}/CO=1). We have observed that the Fe-based catalysts prepared in this project display also a high hydrocarbon synthesis rate with substoichiometric synthesis gas (H{sub 2}/CO=1) stream, which is a less desirable reactant mixture than stoichiometric synthesis gas (H{sub 2}/CO=2). We have improved the catalyst preparation protocols and achieved the highest FTS reaction rates and selectivities so far reported at the low temperatures required for selectivity and stability. Also, we have characterized the catalyst structural change and active phases formed, and their catalytic behavior during the activation process to evaluate their influences on FTS reaction. The efforts of this project led to (i

  13. All-gas-phase synthesis of UiO-66 through modulated atomic layer deposition

    PubMed Central

    Lausund, Kristian Blindheim; Nilsen, Ola

    2016-01-01

    Thin films of stable metal-organic frameworks (MOFs) such as UiO-66 have enormous application potential, for instance in microelectronics. However, all-gas-phase deposition techniques are currently not available for such MOFs. We here report on thin-film deposition of the thermally and chemically stable UiO-66 in an all-gas-phase process by the aid of atomic layer deposition (ALD). Sequential reactions of ZrCl4 and 1,4-benzenedicarboxylic acid produce amorphous organic–inorganic hybrid films that are subsequently crystallized to the UiO-66 structure by treatment in acetic acid vapour. We also introduce a new approach to control the stoichiometry between metal clusters and organic linkers by modulation of the ALD growth with additional acetic acid pulses. An all-gas-phase synthesis technique for UiO-66 could enable implementations in microelectronics that are not compatible with solvothermal synthesis. Since this technique is ALD-based, it could also give enhanced thickness control and the possibility to coat irregular substrates with high aspect ratios. PMID:27876797

  14. All-gas-phase synthesis of UiO-66 through modulated atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Lausund, Kristian Blindheim; Nilsen, Ola

    2016-11-01

    Thin films of stable metal-organic frameworks (MOFs) such as UiO-66 have enormous application potential, for instance in microelectronics. However, all-gas-phase deposition techniques are currently not available for such MOFs. We here report on thin-film deposition of the thermally and chemically stable UiO-66 in an all-gas-phase process by the aid of atomic layer deposition (ALD). Sequential reactions of ZrCl4 and 1,4-benzenedicarboxylic acid produce amorphous organic-inorganic hybrid films that are subsequently crystallized to the UiO-66 structure by treatment in acetic acid vapour. We also introduce a new approach to control the stoichiometry between metal clusters and organic linkers by modulation of the ALD growth with additional acetic acid pulses. An all-gas-phase synthesis technique for UiO-66 could enable implementations in microelectronics that are not compatible with solvothermal synthesis. Since this technique is ALD-based, it could also give enhanced thickness control and the possibility to coat irregular substrates with high aspect ratios.

  15. All-gas-phase synthesis of UiO-66 through modulated atomic layer deposition.

    PubMed

    Lausund, Kristian Blindheim; Nilsen, Ola

    2016-11-23

    Thin films of stable metal-organic frameworks (MOFs) such as UiO-66 have enormous application potential, for instance in microelectronics. However, all-gas-phase deposition techniques are currently not available for such MOFs. We here report on thin-film deposition of the thermally and chemically stable UiO-66 in an all-gas-phase process by the aid of atomic layer deposition (ALD). Sequential reactions of ZrCl4 and 1,4-benzenedicarboxylic acid produce amorphous organic-inorganic hybrid films that are subsequently crystallized to the UiO-66 structure by treatment in acetic acid vapour. We also introduce a new approach to control the stoichiometry between metal clusters and organic linkers by modulation of the ALD growth with additional acetic acid pulses. An all-gas-phase synthesis technique for UiO-66 could enable implementations in microelectronics that are not compatible with solvothermal synthesis. Since this technique is ALD-based, it could also give enhanced thickness control and the possibility to coat irregular substrates with high aspect ratios.

  16. Hydrogen enrichment of synthesis gas for once-through methanol production: Final report

    SciTech Connect

    Cavaliere, G.F.; Riley, C.J.

    1987-04-01

    A previous report, EPRI AP-3749, included the economics of producing methanol fuel from coal gasifiers by a once-through methanol synthesis plant configuration, using the unconverted gas as a gas turbine fuel in a combined-cycle power plant. In that study, the CO-rich gas was adjusted by shift conversion to a composition suitable for methanol synthesis. In the present study, the shift conversion method of gas composition adjustment was compared against several CO-rejection methods, with the rejected CO-rich gas used as fuel for production of power. All cases assumed the same gasification plant size. As a result, the CO-rejection methods produced more electric power and less methanol than the base case of shift conversion. Two alternatives, one based on physical adsorption and one on chemical absorption, were quickly eliminated as uncompetitive on cost grounds and unproven commercially on this scale. The remaining alternatives are membrane separation and cryogenic fractionation. Flowsheets and cost estimates were prepared for these cases and for the shift conversion base case. Total required revenues were calculated for all cases. Then, making reasonable assumptions of the range of unit revenue values of produced methanol and power, competitiveness of the alternatives with the base case was estimated. Some unit revenue combinations gave small revenue advantages for the alternatives, while others gave small advantages for the base case. None of the revenue differentials can be regarded as significant when compared with the accuracy levels of the total cost and income figures being compared. Therefore, both the membrane and cryogenic based process routes are judged to be competitive with the shift-based process, but none of the processes is clearly superior to another using current economic criteria. 1 ref., 32 figs., 19 tabs.

  17. Conversion of Mixed Oxygenates Generated from Synthesis Gas to Fuel Range Hydrocarbon

    SciTech Connect

    Ramasamy, Karthikeyan K.; Gerber, Mark A.; Lilga, Michael A.; Flake, Matthew D.

    2012-08-19

    The growing dependence in the U.S. on foreign crude oil supplies and increased concerns regarding greenhouse gas emission has generated considerable interest in research to develop renewable and environmentally friendly liquid hydrocarbon transportation fuels. One of the strategies for achieving this is to produce intermediate compounds such as alcohols and other simple oxygenates from biomass generated synthesis gas (mixture of carbon monoxide and hydrogen) and further convert them into liquid hydrocarbons. The focus of this research is to investigate the effects of mixed oxygenates intermediate product compositions on the conversion step to produce hydrocarbon liquids. A typical mixed oxygenate stream is expected to contain water (around 50%), alcohols, such as methanol and ethanol (around 35%), and smaller quantities of oxygenates such as acetaldehyde, acetic acid and ethyl acetate. However the ratio and the composition of the mixed oxygenate stream generated from synthesis gas vary significantly depending on the catalyst used and the process conditions. Zeolite catalyzed deoxygenation of methanol accompanied by chain growth is well understood under Methanol-to-Gasoline (MTG) like reaction conditions using an H-ZSM-5 zeolite as the catalyst6-8. Research has also been conducted to a limited extent in the past with higher alcohols, but not with other oxygenates present9-11. Also there has been little experimental investigation into mixtures containing substantial amounts of water. The latter is of particular interest because water separation from the hydrocarbon product would be less energy intensive than first removing it from the oxygenate intermediate stream prior to hydrocarbon synthesis, potentially reducing overall processing costs.

  18. Liquid phase low temperature method for production of methanol from synthesis gas and catalyst formulations therefor

    DOEpatents

    Mahajan, Devinder

    2005-07-26

    The invention provides a homogenous catalyst for the production of methanol from purified synthesis gas at low temperature and low pressure which includes a transition metal capable of forming transition metal complexes with coordinating ligands and an alkoxide, the catalyst dissolved in a methanol solvent system, provided the transition metal complex is not transition metal carbonyl. The coordinating ligands can be selected from the group consisting of N-donor ligands, P-donor ligands, O-donor ligands, C-donor ligands, halogens and mixtures thereof.

  19. Microbial conversion of synthesis gas components to useful fuels and chemicals

    SciTech Connect

    Madhukar, G.R.; Elmore, B.B.; Huckabay, H.K.

    1996-12-31

    Enriched culture techniques have been used to isolate microbial cultures exhibiting growth on synthesis gas components. Three rod-shaped, gram-positive cultures have been isolated from petroleum-contaminated soil, a cow manure-soil mixture, and sheep rumen fluid. Each culture exhibits growth on carbon monoxide as its primary carbon source, producing alcohols and acids in the fermentation medium. Quantities of up to 7.5, 0.58, and 0.25 g/L of acetate, ethanol, and methanol, respectively, have been produced in batch culture with lesser amounts of acetone, butyric, and propionic acid detected. 15 refs., 5 figs., 3 tabs.

  20. Synthesis Methods, Microscopy Characterization and Device Integration of Nanoscale Metal Oxide Semiconductors for Gas Sensing

    PubMed Central

    Vander Wal, Randy L.; Berger, Gordon M.; Kulis, Michael J.; Hunter, Gary W.; Xu, Jennifer C.; Evans, Laura

    2009-01-01

    A comparison is made between SnO2, ZnO, and TiO2 single-crystal nanowires and SnO2 polycrystalline nanofibers for gas sensing. Both nanostructures possess a one-dimensional morphology. Different synthesis methods are used to produce these materials: thermal evaporation-condensation (TEC), controlled oxidation, and electrospinning. Advantages and limitations of each technique are listed. Practical issues associated with harvesting, purification, and integration of these materials into sensing devices are detailed. For comparison to the nascent form, these sensing materials are surface coated with Pd and Pt nanoparticles. Gas sensing tests, with respect to H2, are conducted at ambient and elevated temperatures. Comparative normalized responses and time constants for the catalyst and noncatalyst systems provide a basis for identification of the superior metal-oxide nanostructure and catalyst combination. With temperature-dependent data, Arrhenius analyses are made to determine activation energies for the catalyst-assisted systems. PMID:22408484

  1. Gas-Phase Synthesis of 1-Silacyclopenta-2,4-diene.

    PubMed

    Yang, Tao; Dangi, Beni B; Thomas, Aaron M; Sun, Bing-Jian; Chou, Tzu-Jung; Chang, Agnes H H; Kaiser, Ralf I

    2016-07-04

    Silole (1-silacyclopenta-2,4-diene) was synthesized for the first time by the bimolecular reaction of the simplest silicon-bearing radical, silylidyne (SiH), with 1,3-butadiene (C4 H6 ) in the gas phase under single-collision conditions. The absence of consecutive collisions of the primary reaction product prevents successive reactions of the silole by Diels-Alder dimerization, thus enabling the clean gas-phase synthesis of this hitherto elusive cyclic species from acyclic precursors in a single-collision event. Our method opens up a versatile and unconventional path to access a previously rather obscure class of organosilicon molecules (substituted siloles), which have been difficult to access through classical synthetic methods.

  2. Oxygen carrier development for chemical looping combustion of coal derived synthesis gas

    SciTech Connect

    Siriwardane, R.V.; Chaudhari, K.; Zinn, A.N.; Simonyi, T.; Robinson, Clark; Poston, J.A.

    2006-09-01

    In the present work, NETL researchers have studied chemical looping combustion (CLC) with an oxygen carrier NiO/bentonite (60 wt.% NiO) for the IGCC systems utilizing simulated synthesis gas. Multi cycle CLC was conducted with NiO/Bentonite in TGA at atmospheric pressure and in a high pressure reactor in a temperature range between 700-900°C. Global reaction rates of reduction and oxidation as a function of conversion were calculated for all oxidation-reduction cycles utilizing the TGA data. The effect of particle size of the oxygen carrier on CLC was studied for the size between 20-200 mesh. The multi cycle CLC tests conducted in a high pressure packed bed flow reactor indicated constant total production of CO2 from fuel gas at 800°C and 900°C and full consumption of hydrogen during the reaction.

  3. Synthesis and application of graphene-silver nanowires composite for ammonia gas sensing

    NASA Astrophysics Data System (ADS)

    Tran, Quang Trung; Hoa Huynh, Tran My; Tong, Duc Tai; Tam Tran, Van; Dinh Nguyen, Nang

    2013-12-01

    Graphene, consisting of a single carbon layer in a two-dimensional (2D) lattice, has been a promising material for application to nanoelectrical devices in recent years. In this study we report the development of a useful ammonia (NH3) gas sensor based on graphene-silver nanowires ‘composite’ with planar electrode structure. The basic strategy involves three steps: (i) preparation of graphene oxide (GO) by modified Hummers method; (ii) synthesis of silver nanowires by polyol method; and (iii) preparation of graphene and silver nanowires on two electrodes using spin and spray-coating of precursor solutions, respectively. Exposure of this sensor to NH3 induces a reversible resistance change at room temperature that is as large as ΔR/R0 ˜ 28% and this sensitivity is eight times larger than the sensitivity of the ‘intrinsic’ graphene based NH3 gas sensor (ΔR/R0 ˜ 3,5%). Their responses and the recovery times go down to ˜200 and ˜60 s, respectively. Because graphene synthesized by chemical methods has many defects and small sheets, it cannot be perfectly used for gas sensor or for nanoelectrical devices. The silver nanowires are applied to play the role of small bridges connecting many graphene islands together to improve electrical properties of graphene/silver nanowires composite and result in higher NH3 gas sensitivity.

  4. Synthesis of Highly Porous Coordination Polymers with Open Metal Sites for Enhanced Gas Uptake and Separation.

    PubMed

    Song, Kyung Seob; Kim, Daeok; Polychronopoulou, Kyriaki; Coskun, Ali

    2016-10-12

    Metal-containing amorphous microporous polymers are an emerging class of functional porous materials in which the surface properties and functions of polymers are dictated by the nature of the metal ions incorporated into the framework. In an effort to introduce coordinatively unsaturated metal sites into the porous polymers, we demonstrate herein an aqueous-phase synthesis of porous coordination polymers (PCPs) incorporating bis(o-diiminobenzosemiquinonato)-Cu(II) or -Ni(II) bridges by simply reacting hexaminotriptycene with CuSO4·5H2O [Cu(II)-PCP] or NiCl2·6H2O [Ni(II)-PCP] in H2O. The resulting polymers showed surface areas of up to 489 m(2) g(-1) along with a narrow pore size distribution. The presence of open metal sites significantly improved the gas affinity of these frameworks, leading to an exceptional isosteric heat of adsorption of 10.3 kJ·mol(-1) for H2 at zero coverage. The high affinities of Cu(II)- and Ni(II)-PCPs toward CO2 prompted us to investigate the removal of CO2 from natural and landfill gas conditions. We found that the higher affinity of Cu(II)-PCP compared to that of Ni(II)-PCP not only allowed for the tuning of the affinity of CO2 molecules toward the sorbent, but also led to an exceptional CO2/CH4 selectivity of 35.1 for landfill gas and 20.7 for natural gas at 298 K. These high selectivities were further verified by breakthrough measurements under the simulated natural and landfill gas conditions, in which both Cu(II)- and Ni(II)-PCPs showed complete removal of CO2. These results clearly demonstrate the promising attributes of metal-containing porous polymers for gas storage and separation applications.

  5. Single-step gas phase synthesis of stable iron aluminide nanoparticles with soft magnetic properties

    SciTech Connect

    Vernieres, Jerome Benelmekki, Maria; Kim, Jeong-Hwan; Grammatikopoulos, Panagiotis; Diaz, Rosa E.; Bobo, Jean-François; Sowwan, Mukhles

    2014-11-01

    Soft magnetic alloys at the nanoscale level have long generated a vivid interest as candidate materials for technological and biomedical purposes. Consequently, controlling the structure of bimetallic nanoparticles in order to optimize their magnetic properties, such as high magnetization and low coercivity, can significantly boost their potential for related applications. However, traditional synthesis methods stumble upon the long standing challenge of developing true nanoalloys with effective control over morphology and stability against oxidation. Herein, we report on a single-step approach to the gas phase synthesis of soft magnetic bimetallic iron aluminide nanoparticles, using a versatile co-sputter inert gas condensation technique. This method allowed for precise morphological control of the particles; they consisted of an alloy iron aluminide crystalline core (DO{sub 3} phase) and an alumina shell, which reduced inter-particle interactions and also prevented further oxidation and segregation of the bimetallic core. Remarkably, the as-deposited alloy nanoparticles show interesting soft magnetic properties, in that they combine a high saturation magnetization (170 emu/g) and low coercivity (less than 20 Oe) at room temperature. Additional functionality is tenable by modifying the surface of the particles with a polymer, to ensure their good colloidal dispersion in aqueous environments.

  6. Bench-scale demonstration of biological production of ethanol from coal synthesis gas

    SciTech Connect

    Not Available

    1992-01-01

    Culture isolation and selection studies are being performed in order to select the best biological system for bench-scale studies in producing ethanol from syngas components. Three isolates have been found which produce more than 2 g/L ethanol from CO and C0[sub 2]/H[sub 2] in batch culture. These low concentrations are actually quite promising since Clostridium ljungdahlii, strain PETC, performs well in continuous culture but produces only small concentrations of ethanol in batch culture after several weeks of incubation. Two of the isolates have been utilized in the CSTR, where 90 percent CO conversions have been noted, while producing up to 2 g/L ethanol, in preliminary studies. CSTR studies will continue until steady state is reached. An anaerobic bacterium has been isolated from natural sources that converts the components of synthesis gas (CO, H[sub 2],C0[sub 2]) into ethanol. This organism, the only one known at that time to produce ethanol from synthesis gas, has been identified as a new clostridial strain and has been named Clostridium ljungdahlii, strain PETC.

  7. Iron particle size effects for direct production of lower olefins from synthesis gas.

    PubMed

    Torres Galvis, Hirsa M; Bitter, Johannes H; Davidian, Thomas; Ruitenbeek, Matthijs; Dugulan, A Iulian; de Jong, Krijn P

    2012-10-03

    The Fischer-Tropsch synthesis of lower olefins (FTO) is an alternative process for the production of key chemical building blocks from non-petroleum-based sources such as natural gas, coal, or biomass. The influence of the iron carbide particle size of promoted and unpromoted carbon nanofiber supported catalysts on the conversion of synthesis gas has been investigated at 340-350 °C, H(2)/CO = 1, and pressures of 1 and 20 bar. The surface-specific activity (apparent TOF) based on the initial activity of unpromoted catalysts at 1 bar increased 6-8-fold when the average iron carbide size decreased from 7 to 2 nm, while methane and lower olefins selectivity were not affected. The same decrease in particle size for catalysts promoted by Na plus S resulted at 20 bar in a 2-fold increase of the apparent TOF based on initial activity which was mainly caused by a higher yield of methane for the smallest particles. Presumably, methane formation takes place at highly active low coordination sites residing at corners and edges, which are more abundant on small iron carbide particles. Lower olefins are produced at promoted (stepped) terrace sites that are available and active, quite independent of size. These results demonstrate that the iron carbide particle size plays a crucial role in the design of active and selective FTO catalysts.

  8. Gas phase microreaction: nanomaterials synthesis via plasma exposure of liquid droplets

    NASA Astrophysics Data System (ADS)

    Maguire, Paul; Mahony, Charles; Kelsey, Colin; Hamilton, Neil; Askari, Sadegh; Macias-Montero, Manuel; Diver, Declan; Mariotti, Davide

    2015-09-01

    Plasma-liquid interactions are complex but offer considerable scope for use in nanomaterials synthesis. The introduction of individual picolitre micro-droplets into a steady-state low temperature plasma at atmospheric pressure, offers opportunities for enhanced scope and control of plasma-liquid chemistry and material properties. The gas-phase micro-reactor is similar in concept to liquid bubble microfluidics currently under intense research but with enhanced opportunities for scale-up. For nanomaterials and quantum dot synthesis, the addition of a liquid phase within the plasma expands considerably the scope for core-shell and alloy formation. The synthesis and encapsulation within a liquid droplet allows continuous delivery of nanoparticles to remote sites for plasma medicine, device fabrication or surface coating. We have synthesized Au nanoparticles in flight using AuHCl4 droplets with plasma flight times <0.1 ms. Also, Ag nanoparticles have been synthesized downstream via the delivery of plasma exposed water droplets onto AgNO3 laden substrates. Funding from EPSRC acknowledged (Grants EP/K006088/1 and EP/K006142/1).

  9. Ammonia synthesis

    SciTech Connect

    Mandelik, B.G.; Cassata, J.R.; Katy, P.J.S.; Van Dijk, C.P.

    1986-02-04

    In a process for producing ammonia in a synthesis loop in which fresh synthesis gas containing hydrogen, nitrogen and, lesser amounts of argon and methane is combined with a hydrogen enriched recycle gas to provide combined synthesis gas, the combined synthesis is introduced to and reacted over ammonia synthesis catalyst under synthesis conditions to provide converted gas containing ammonia, hydrogen, and nitrogen. The ammonia is recovered from the converted gas to provide recycle gas, and a purge stream is removed from the synthesis loop. A hydrogen-rich gas is recovered from the purge stream, and the hydrogen-rich gas is combined with the recycle gas to provide the hydrogen enriched gas. The improvement described in this patent consists of (a) providing the fresh synthesis gas at a hydrogen to nitrogen molar ratio between 1.7 and 2.5 and providing the hydrogen enriched recycle gas at a hydrogen to nitrogen molar ratio between 0.5 and 1.7 to provide the combined synthesis gas at a hydrogen to nitrogen molar ratio between 0.8 and 1.8. The volumetric flow rate ratio of the hydrogen enriched recycle gas to the fresh synthesis gas is between 2.2 and 3.7; and (b) introducing the combined synthesis gas from step (a) to an ammonia synthesis catalyst at a temperature between 315/sup 0/C. and 400/sup 0/C. and a pressure between 50 kg/cm/sup 2/ and 150 kg/cm/sup 2/.

  10. Size-controlled synthesis and gas sensing application of tungsten oxide nanostructures produced by arc discharge.

    PubMed

    Fang, F; Kennedy, J; Futter, J; Hopf, T; Markwitz, A; Manikandan, E; Henshaw, G

    2011-08-19

    Several different synthetic methods have been developed to fabricate tungsten oxide (WO(3)) nanostructures, but most of them require exotic reagents or are unsuitable for mass production. In this paper, we present a systematic investigation demonstrating that arc discharge is a fast and inexpensive synthesis method which can be used to produce high quality tungsten oxide nanostructures for NO(2) gas sensing measurements. The as-synthesized WO(3) nanostructures are characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), finger-print Raman spectroscopy and proton induced x-ray emission (PIXE). The analysis shows that spheroidal-shaped monoclinic WO(3) crystal nanostructures were produced with an average diameter of 30 nm (range 10-100 nm) at an arc discharge current of 110 A and 300 Torr oxygen partial pressure. It is found that the morphology is controlled by the arc discharge parameters of current and oxygen partial pressure, e.g. a high arc discharge current combined with a low oxygen partial pressure results in small WO(3) nanostructures with improved conductivity. Sensors produced from the WO(3) nanostructures show a strong response to NO(2) gas at 325 °C. The ability to tune the morphology of the WO(3) nanostructures makes this method ideal for the fabrication of gas sensing materials.

  11. On-line gas chromatographic analysis of higher alcohol synthesis products from syngas.

    PubMed

    Andersson, Robert; Boutonnet, Magali; Järås, Sven

    2012-07-20

    An on-line gas chromatographic (GC) system has been developed for rapid and accurate product analysis in catalytic conversion of syngas (a mixture of H₂ and CO) to alcohols, so called "higher alcohol synthesis (HAS)". Conversion of syngas to higher alcohols is an interesting second step in the route of converting coal, natural gas and possibly biomass to liquid alcohol fuel and chemicals. The presented GC system and method are developed for analysis of the products formed from syngas using alkali promoted MoS₂ catalysts, however it is not limited to these types of catalysts. During higher alcohol synthesis not only the wanted short alcohols (∼C₂-C₅) are produced, but also a great number of other products in smaller or greater amounts, they are mainly short hydrocarbons (olefins, paraffins, branched, non-branched), aldehydes, esters and ketones as well as CO₂, H₂O. Trace amounts of sulfur-containing compounds can also be found in the product effluent when sulfur-containing catalysts are used and/or sulfur-containing syngas is feed. In the presented GC system, most of them can be separated and analyzed within 60 min without the use of cryogenic cooling. Previously, product analysis in "higher alcohol synthesis" has in most cases been carried out partly on-line and partly off-line, where the light gases (gases at room temp) are analyzed on-line and liquid products (liquid at room temp) are collected in a trap for later analysis off-line. This method suffers from many drawbacks compared to a complete on-line GC system. In this paper an on-line system using an Agilent 7890 gas chromatograph equipped with two flame ionization detectors (FID) and a thermal conductivity detector (TCD), together with an Agilent 6890 with sulfur chemiluminescence dual plasma detector (SCD) is presented. A two-dimensional GC system with Deans switch (heart-cut) and two capillary columns (HP-FFAP and HP-Al₂O₃) was used for analysis of the organic products on the FIDs. Light

  12. Synthesis of a further improved porous polymer for the separation of nitrogen, oxygen, argon, and carbon monoxide by gas chromatography

    NASA Technical Reports Server (NTRS)

    Pollock, G. E.

    1986-01-01

    A further improvement has been made in the synthesis of an N-type porous polymer for the separation of permanent gases. Changing the ratios of reactants and diluting the Hi-DVB with styrene led to a porous polymer gas chromatographic packing which is superior to commercial products and to the author's own previously reported custom-made polymer.

  13. Selective production of alpha olefins from synthesis gas over ZnO supported Pd-Fe bimetallics

    SciTech Connect

    Gustafson, B.L.; Wehner, P.S.

    1986-01-01

    Olefins are basic raw materials for a wide variety of commercial processes within the chemical industry. A synthesis-gas-based route to low molecular weight ..cap alpha..-olefins would provide the chemical industry with an alternative route to raw materials in the advent of future petroleum shortages or price increases. The catalytic production of ..cap alpha..-olefins from synthesis gas has been the subject of many investigations over the past 50 years. It has been established that, in some systems, olefin selectivity can be enhanced through the addition of various promoters such as K, Mn, Ti, or Zn. Olefin selectivity can also be dependent on process parameters such as temperature, pressure, conversion levels, or feed compositions. Recent reports in the literature indicate that supported Fe-containing bimetallics may also be selective for the production of olefins from synthesis gas. This study reports the use of Pd-FE bimetallics supported on ZnO for the selective production of olefins from synthesis gas.

  14. High octane ethers from synthesis gas-derived alcohols. Final technical report, September 25, 1990--December 24, 1993

    SciTech Connect

    Klier, K.; Herman, R.G.

    1994-05-01

    The objective of the research was to develop the methodology for the catalytic synthesis of ethers, primarily methyl isobutyl ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from alcohol mixtures that are rich in methanol and 2-methyl-1-propanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers. The last stage of the synthesis involves direct coupling of synthesis gas-derived methanol and isobutanol that has been previously demonstrated by us to occur over superacid catalysts to yield MIBE and smaller amounts of MTBE at moderate pressures and a mixture of methanol and isobutene at low pressures. A wide range of organic resin catalysts and inorganic oxide and zeolite catalysts have been investigated for activity and selectivity in directly coupling alcohols, principally methanol and isobutanol, to form ethers and in the dehydration of isobutanol to isobutene in the presence of methanol. All of these catalysts are strong acids, and it was found that the organic and inorganic catalysts operate in different, but overlapping, temperature ranges, i.e. mainly 60--120{degrees}C for the organic resins and 90--175{degrees}C for the inorganic catalysts. For both types of catalysts, the presence of strong acid centers is required for catalytic activity, as was demonstrated by lack of activity of fully K{sup +} ion exchanged Nafion resin and zirconia prior to being sulfated by treatment with sulfuric acid.

  15. Synthesis of highly selective zeolite topology molecular sieve for adsorption of benzene gas

    NASA Astrophysics Data System (ADS)

    Wei, Lin; Chen, Yunlin; Zhang, Baoping; Zu, Zhinan

    2013-02-01

    Shangdong fly ash (SFA), Fangshan fly ash (FFA) and Heilongjiang fly ash (HFA) were selected as the raw materials to be used for synthesis of highly selective zeolite topology molecular sieve. Twice foaming method was studied in terms of synthetic zeolite. The experimental products were characterized by means of X-ray fluorescence (XRF), scanning electron microscope (SEM), X-ray diffraction (XRD), and automated surface area & pore size analyser. The results indicated that 10 M NaOH was chosen as modification experiment condition to process SFA. Crystallization temperature and time were 140 °C and 8 h, respectively. Zeolite topology molecular sieve was prepared with Si/Al molar ratio of 7.9, and its adsorption ratio of benzene gas was up to 66.51%.

  16. Luminescence study of nanosized Al2O3:Tb3+ obtained by gas-dispersed synthesis

    NASA Astrophysics Data System (ADS)

    Berezovskaya, I. V.; Poletaev, N. I.; Khlebnikova, M. E.; Zatovsky, I. V.; Bychkov, K. L.; Efryushina, N. P.; Khomenko, O. V.; Dotsenko, V. P.

    2016-09-01

    Terbium-doped Al2O3 samples were obtained by gas-dispersed synthesis. It was shown that the resulting powders, with particle sizes of 10-70 nm, consist of a mixture of transition aluminas, among which the δ *-polymorph is dominant. The luminescence properties of Al2O3:Tb3+ have been studied upon excitation in the UV-visible range of the spectrum. It was found that Tb3+ ions cause several groups of inhomogeneously broadened emission bands in the range of 470-640 nm, which are characteristic for disordered materials. In addition, the emission spectra contain a broad band at about 450 nm and several narrower ones in the 680-720 nm region. These features are attributed to surface defects and impurity Cr3+ ions occupying Al3+ octahedral positions, respectively.

  17. Design and Operation of the Synthesis Gas Generator System for Reformed Propane and Glycerin Combustion

    NASA Astrophysics Data System (ADS)

    Pickett, Derek Kyle

    Due to an increased interest in sustainable energy, biodiesel has become much more widely used in the last several years. Glycerin, one major waste component in biodiesel production, can be converted into a hydrogen rich synthesis gas to be used in an engine generator to recover energy from the biodiesel production process. This thesis contains information detailing the production, testing, and analysis of a unique synthesis generator rig at the University of Kansas. Chapter 2 gives a complete background of all major components, as well as how they are operated. In addition to component descriptions, methods for operating the system on pure propane, reformed propane, reformed glycerin along with the methodology of data acquisition is described. This chapter will serve as a complete operating manual for future students to continue research on the project. Chapter 3 details the literature review that was completed to better understand fuel reforming of propane and glycerin. This chapter also describes the numerical model produced to estimate the species produced during reformation activities. The model was applied to propane reformation in a proof of concept and calibration test before moving to glycerin reformation and its subsequent combustion. Chapter 4 first describes the efforts to apply the numerical model to glycerin using the calibration tools from propane reformation. It then discusses catalytic material preparation and glycerin reformation tests. Gas chromatography analysis of the reformer effluent was completed to compare to theoretical values from the numerical model. Finally, combustion of reformed glycerin was completed for power generation. Tests were completed to compare emissions from syngas combustion and propane combustion.

  18. Highly size-controlled synthesis of Au/Pd nanoparticles by inert-gas condensation.

    PubMed

    Pérez-Tijerina, E; Pinilla, M Gracia; Mejía-Rosales, S; Ortiz-Méndez, U; Torres, A; José-Yacamán, M

    2008-01-01

    Gold/Palladium nanoparticles were fabricated by inert-gas condensation on a sputtering reactor. With this method, by controlling both the atmosphere on the condensation chamber and the magnetron power, it was possible to produce nanoparticles with a high degree of monodispersity in size. The structure and size of the Au/Pd nanoparticles were determined by mass spectroscopy, and confirmed by atomic force microscopy and electron transmission microscopy measurements. The chemical composition was analyzed by X-ray microanalysis. From these measurements we confirmed that with the sputtering technique we are able to produce particles of 1, 3, and 5 nm on size, depending on the choice of the synthesis conditions. From TEM measurements made both in the regular HREM, as well as in STEM-HAADF mode, we found that the particles are icosahedral in shape, and the micrographs show no evidence of a core-shell structure, in contrast to what is observed in the case of nanoparticles prepared by chemical synthesis.

  19. Gas-phase laser synthesis of aggregation-free, size-controlled hydroxyapatite nanoparticles

    NASA Astrophysics Data System (ADS)

    Bapat, Parimal V.; Kraft, Rebecca; Camata, Renato P.

    2012-10-01

    Nanophase hydroxyapatite (HA) is finding applications in many areas of biomedical research, including bone tissue engineering, drug delivery, and intracellular imaging. Details in chemical composition, crystal phase makeup, size, and shape of HA nanoparticles play important roles in achieving the favorable biological responses required in these applications. Most of the nanophase HA synthesis techniques involve solution-based methods that exhibit substantial aggregation of particles upon precipitation. Typically these methods also have limited control over the particle size and crystal phase composition. In this study, we describe the gas-phase synthesis of aggregation-free, size-controlled HA nanoparticles with mean size in the 20-70 nm range using laser ablation followed by aerosol electrical mobility classification. Nanoparticle deposits with adjustable number concentration were obtained on solid substrates. Particles were characterized by transmission electron microscopy, atomic force microscopy, and X-ray diffraction. Samples are well represented by log-normal size distributions with geometric standard deviation σ g ≈ 1.2. The most suitable conditions for HA nanoparticle formation at a laser fluence of 5 J/cm2 were found to be a temperature of 800 °C and a partial pressure of water of 160 mbar.

  20. Synthesis of ZnO:Ge Thin Films via Plasma Gas Condensation

    NASA Astrophysics Data System (ADS)

    Ceylan, Abdullah; Ali, Janan; Ozcan, Sadan

    2013-03-01

    we introduce a new method for the synthesis of Ge nanoparticle embedded ZnO thin films that are considered to be a potential candidate for photovoltaic applications. As opposed to current techniques, for the independent preparation of Ge nanoparticles, Cluster Deposition Source (CDS) utilising gas condensation of sputtered Ge atoms is used. For the synthesis of ZnO thin film host material conventional sputtering is employed. In the proposed technique independently synthesized Ge nanoparticles and ZnO thin films are combined into a composite structure on Si. XRD patterns of the samples have revealed that Ge nanoparticles preferentially settle on (113) planes on top of the (002) oriented ZnO layer. It is realized that Ge nanoparticles with sizes ranging from 16 nm to 20 nm could be embedded into a well-defined ZnO matrix. In fact, TEM studies performed on Ge nanoparticles captured on a Cu grids have manifested that Ge reach to ZnO matrix as clusters composed of particles with sizes of about 7-8 nm and then eventually grow larger due to substrate heating implemented during capping layer deposition. Optical absorption measurements have revealed that Ge nanoparticle inclusion lead to an additional absorption edge at about 2.75 eV along with 3.17 eV edge resulting from ZnO host.

  1. The Fuel Processing Research Facility - A Platform for the Conduct of Synthesis Gas Technology R&D

    SciTech Connect

    Monahan, Michael J.; Berry, David A.; Gardner, Todd H.; Lyons, K. David

    2001-11-06

    Vision 21 is the U. S. Department of Energy's initiative to deploy high efficiency, ultraclean co-production coal conversion power plants in the twenty-first century. These plants will consist of power and co-production modules, which are integrated to meet specific power and chemical markets. A variety of fuel gas processing technology issues involving gas separations, cleanup, gas-to-liquid fuels production and chemical synthesis, to mention a few, will be addressed by the program. The overall goal is to effectively eliminate, at competitive costs, environmental concerns associated with the use of fossil fuels for producing electricity and transportation fuels. The Fuel Processing Research Facility (FPRF) was developed as a fuel-flexible platform to address many of these technology needs. The facility utilizes a simplified syngas generator that is capable of producing 2,000 standard cubic feet per hour of 900 degree Celsius and 30 atmosphere synthesis gas that can be tailored to the gas composition of interest. It was built on a ''mid-scale'' level in an attempt to successfully branch the traditionally difficult scale-up from laboratory to pilot scale. When completed, the facility will provide a multi-faceted R&D area for the testing of fuel cells, gas separation technologies, and other gas processing unit operations.

  2. Method of producing synthesis gas by underground gasification of coal using specific well configuration

    SciTech Connect

    Gash, B.W.; Arri, L.E.; Hunt, E.B. Jr.; Parrish, D.R.

    1987-03-10

    A method is described of producing synthesis gas by the underground gasification of coal in individual noninteracting cavities formed by the gasification of the coal in a thick coal seam which is generally horizontal under an overburden and wherein loose coal and char formed from the combustion of the coal in the seam have a known angle of repose. The seam is provided with an injection well positioned at an angle with respect to the horizontal of less than the angle of repose and with a production well positioned at an angle with respect to the horizontal of greater than the angle of repose but less than 90/sup 0/. The distance between the wells decreases toward the bottom of the seam. The method comprises linking the wells, initiating combustion near the bottom of the seam and thereby producing a cavity in the seam, introducing an oxygen-containing gas mixture into the seam through the injection well, and removing combustion products through the production well.

  3. High Temperature Polybenzimidazole Hollow Fiber Membranes for Hydrogen Separation and Carbon Dioxide Capture from Synthesis Gas

    DOE PAGES

    Singh, Rajinder P.; Dahe, Ganpat J.; Dudeck, Kevin W.; ...

    2014-12-31

    Sustainable reliance on hydrocarbon feedstocks for energy generation requires CO₂ separation technology development for energy efficient carbon capture from industrial mixed gas streams. High temperature H₂ selective glassy polymer membranes are an attractive option for energy efficient H₂/CO₂ separations in advanced power production schemes with integrated carbon capture. They enable high overall process efficiencies by providing energy efficient CO₂ separations at process relevant operating conditions and correspondingly, minimized parasitic energy losses. Polybenzimidazole (PBI)-based materials have demonstrated commercially attractive H₂/CO₂ separation characteristics and exceptional tolerance to hydrocarbon fuel derived synthesis (syngas) gas operating conditions and chemical environments. To realize a commerciallymore » attractive carbon capture technology based on these PBI materials, development of high performance, robust PBI hollow fiber membranes (HFMs) is required. In this work, we discuss outcomes of our recent efforts to demonstrate and optimize the fabrication and performance of PBI HFMs for use in pre-combustion carbon capture schemes. These efforts have resulted in PBI HFMs with commercially attractive fabrication protocols, defect minimized structures, and commercially attractive permselectivity characteristics at IGCC syngas process relevant conditions. The H₂/CO₂ separation performance of these PBI HFMs presented in this document regarding realistic process conditions is greater than that of any other polymeric system reported to-date.« less

  4. High Temperature Polybenzimidazole Hollow Fiber Membranes for Hydrogen Separation and Carbon Dioxide Capture from Synthesis Gas

    SciTech Connect

    Singh, Rajinder P.; Dahe, Ganpat J.; Dudeck, Kevin W.; Welch, Cynthia F.; Berchtold, Kathryn A.

    2014-12-31

    Sustainable reliance on hydrocarbon feedstocks for energy generation requires CO₂ separation technology development for energy efficient carbon capture from industrial mixed gas streams. High temperature H₂ selective glassy polymer membranes are an attractive option for energy efficient H₂/CO₂ separations in advanced power production schemes with integrated carbon capture. They enable high overall process efficiencies by providing energy efficient CO₂ separations at process relevant operating conditions and correspondingly, minimized parasitic energy losses. Polybenzimidazole (PBI)-based materials have demonstrated commercially attractive H₂/CO₂ separation characteristics and exceptional tolerance to hydrocarbon fuel derived synthesis (syngas) gas operating conditions and chemical environments. To realize a commercially attractive carbon capture technology based on these PBI materials, development of high performance, robust PBI hollow fiber membranes (HFMs) is required. In this work, we discuss outcomes of our recent efforts to demonstrate and optimize the fabrication and performance of PBI HFMs for use in pre-combustion carbon capture schemes. These efforts have resulted in PBI HFMs with commercially attractive fabrication protocols, defect minimized structures, and commercially attractive permselectivity characteristics at IGCC syngas process relevant conditions. The H₂/CO₂ separation performance of these PBI HFMs presented in this document regarding realistic process conditions is greater than that of any other polymeric system reported to-date.

  5. Synthesis and gas adsorption study of porous metal-organic framework materials

    NASA Astrophysics Data System (ADS)

    Mu, Bin

    Metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) have become the focus of intense study over the past decade due to their potential for advancing a variety of applications including air purification, gas storage, adsorption separations, catalysis, gas sensing, drug delivery, and so on. These materials have some distinct advantages over traditional porous materials such as the well-defined structures, uniform pore sizes, chemically functionalized sorption sites, and potential for postsynthetic modification, etc. Thus, synthesis and adsorption studies of porous MOFs have increased substantially in recent years. Among various prospective applications, air purification is one of the most immediate concerns, which has urgent requirements to improve current nuclear, biological, and chemical (NBC) filters involving commercial and military purposes. Thus, the major goal of this funded project is to search, synthesize, and test these novel hybrid porous materials for adsorptive removal of toxic industrial chemicals (TICs) and chemical warfare agents (CWAs), and to install the benchmark for new-generation NBC filters. The objective of this study is three-fold: (i) Advance our understanding of coordination chemistry by synthesizing novel MOFs and characterizing these porous coordination polymers; (ii) Evaluate porous MOF materials for gasadsorption applications including CO2 capture, CH4 storage, other light gas adsorption and separations, and examine the chemical and physical properties of these solid adsorbents including thermal stability and heat capacity of MOFs; (iii) Evaluate porous MOF materials for next-generation NBC filter media by adsorption breakthrough measurements of TICs on MOFs, and advance our understanding about structureproperty relationships of these novel adsorbents.

  6. Designed synthesis of nanoporous organic polymers for selective gas uptake and catalytic applications

    NASA Astrophysics Data System (ADS)

    Arab, Pezhman

    Design and synthesis of porous organic polymers have attracted considerable attentions during the past decade due to their wide range of applications in gas storage, gas separation, energy conversion, and catalysis. Porous organic polymers can be pre-synthetically and post-synthetically functionalized with a wide variety of functionalities for desirable applications. Along these pursuits, we introduced new synthetic strategies for preparation of porous organic polymers for selective CO2 capture and catalytic applications. Porous azo-linked polymers (ALPs) were synthesized by an oxidative reaction of amine-based monomers using copper(I) as a catalyst which leads to azo-linkage formation. ALPs exhibit high surface areas of up to 1200 m2 g-1 and have high chemical and thermal stabilities. The nitrogen atoms of the azo group can act as Lewis bases and the carbon atom of CO2 can act as a Lewis acid. Therefore, ALPs show high CO2 uptake capacities due to this Lewis acid-based interaction. The potential applications of ALPs for selective CO2 capture from flue gas, natural gas, and landfill gas under pressure-swing and vacuum swing separation settings were studied. Due to their high CO2 uptake capacity, selectivity, and regenerability, ALPs are among the best porous organic frameworks for selective CO2 capture. In our second project, a new bis(imino)pyridine-linked porous polymer (BIPLP-1) was synthesized and post-synthetically functionalized with Cu(BF4)2 for highly selective CO2 capture. BIPLP-1 was synthesized via a condensation reaction between 2,6-pyridinedicarboxaldehyde and 1,3,5-tris(4-aminophenyl)benzene, wherein the bis(imino)pyridine linkages are formed in-situ during polymerization. The functionalization of the polymer with Cu(BF4)2 was achieved by treatment of the polymer with a solution of Cu(BF4)2 via complexation of copper cations with bis(imino)pyridine moieties of the polymer. BF4- ions can act Lewis base and CO2 can act as a Lewis acid; and therefore

  7. Surfactant assisted solid-state synthesis and gas sensor application of a SWCNT/SnO2 nanocomposite material.

    PubMed

    Lu, Jun; Ma, Anson; Yang, Shihe; Ng, Ka Ming

    2007-01-01

    Although tin oxide has been the most widely investigated metal oxide material for gas detection, it suffers from the large resistance and high operating temperature. This could be overcome by hybridization with nanostructured carbon. In this work, tin oxide nanoparticles with ultrasmall sizes of 1-3 nm have been uniformly coated onto bundles of single-walled carbon nanotubes by a surfactant assisted solid state synthesis approach for the first time. Gas sensor properties of the as-synthesized nanocomposite material toward NO2 (from 5 to 60 ppm) are measured at 150 degrees C. Compared to the pure carbon tubes gas sensors, the nanocomposite gas sensor responds to NO2 in low concentrations with good linearity, high sensitivity, and fast recovery, while working at a relatively low temperature.

  8. Practical experiences with the synthesis of [11C]CH3I through gas phase iodination reaction using a TRACERlabFXC synthesis module.

    PubMed

    Kniess, Torsten; Rode, Katrin; Wuest, Frank

    2008-04-01

    The results of [(11)C]CH(3)I synthesis through hydrogen gas reduction of [(11)C]CO(2) on different nickel catalysts (HARSHAW-nickel, SHIMALITE-nickel, nickel on silica/alumina, nickel nanosize 99.99%) followed by gas phase iodination using a TRACERlab FX(C) synthesis unit are reported. Further reaction parameters such as furnace temperatures, flow rate of hydrogen gas and reduction time were optimized. It was found that reduction of [(11)C]CO(2) proceeded in 28-83% yield depending on the nickel catalyst and temperature. The gas phase iodination (methane conversion) gave 31-62% of [(11)C]CH(3)I depending on temperature and amount of iodine in the iodine furnace. [(11)C]CH(3)I was used for heteroatom methylation reactions exemplified by a piperazine and a phenol (1 and 3). The specific activity of the (11)C-labelled products 2 and 4 was determined after HPLC purification and solid-phase extraction. Compounds 2 and 4 were obtained in 8-14% radiochemical yield (decay-corrected, based upon trapped [(11)C]CH(4)) within 30 min. The specific activity was determined to be in the range of 20-30 GBq/mumol at the end-of-synthesis. Nickel catalyst nanosize was found to be superior compared with other Ni catalysts tested. The relatively low specific activity may be mainly due to carbon contaminations originating from the long copper tubing (500 m) between the cyclotron and the radiochemistry facility.

  9. Bioconversion of coal derived synthesis gas to liquid fuels. Quarterly technical progress report, October 1, 1994--December 27, 1994

    SciTech Connect

    Jain, M.K.; Worden, R.M.; Grethlein, A.

    1995-01-16

    The overall objective of the project is to develop an integrated two-stage fermentation process for conversion of coal-derived synthesis gas to a mixture of alcohols. This is achieved in two steps. In the first step, Butyribacterium methylotrophicum converts carbon monoxide (CO) to butyric and acetic acids. Subsequent fermentation of the acids by Clostridium acetobutylicum leads to the production of butanol and ethanol. The tasks for this quarter were: (1) Development/isolation of superior strains for fermentation of syngas; (2) Evaluation of bioreactor configuration for improved mass transfer of syngas, specifically gas lift; (3) Pervaporation for recovery of solvents; (4) Write and submit final report.

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

    PubMed

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

    2011-09-16

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

  11. Chemical-looping combustion of coal-derived synthesis gas over copper oxide oxygen carriers

    SciTech Connect

    Tian, H.; Chaudhari, K.; Simonyi, T.; Poston, J.; Liu, T.; Sanders, T.; Veser, G.; Siriwardane, R.

    2008-01-01

    CuO/bentonite and CuO-BHA nanocomposites were studied as oxygen carriers in chemical-looping combustion (CLC) of simulated synthesis gas. Global reaction rates of reduction and oxidation, as the function of reaction conversion, were calculated from 10-cycle oxidation/reduction tests utilizing thermogravimetric analysis at atmospheric pressure between 700 and 900 °C. It was found that the reduction reactions are always faster than oxidation reactions; reaction temperature and particle size do not significantly affect the reaction performance of CuO/bentonite. Multicycle CLC tests conducted in a high-pressure flow reactor showed stable reactivity for production of CO2 from fuel gas at 800 and 900 °C and full consumption of hydrogen during the reaction. Results of the tapered element oscillating microbalance showed a negative effect of pressure on the global rates of reduction-oxidation reactions at higher fractional conversions. X-ray diffraction patterns confirmed the presence of CuO in the bulk phase of the oxidized sample. Electron microanalysis showed significant morphology changes of reacted CuO/bentonite samples after the 10 oxidation-reduction cycles above 700 °C in an atmospheric thermogravimetric analyzer. The nanostructured CuO-BHA carrier also showed excellent stability and, in comparison to the CuO/bentonite system, slightly accelerated redox kinetics albeit at the expense of significantly increased complexity of manufacturing. Overall, both types of CuO carriers exhibited excellent reaction performance and thermal stability for the CLC process at 700-900 °C.

  12. Chemical-looping combustion of coal-derived synthesis gas over copper oxide oxygen carriers

    SciTech Connect

    Hanjing Tian; Karuna Chaudhari; Thomas Simonyi; James Poston; Tengfei Liu; Tom Sanders; Goetz Veser; Ranjani Siriwardane

    2008-11-15

    CuO/bentonite and CuO-BHA nanocomposites were studied as oxygen carriers in chemical-looping combustion (CLC) of simulated synthesis gas. Global reaction rates of reduction and oxidation, as the function of reaction conversion, were calculated from 10-cycle oxidation/reduction tests utilizing thermogravimetric analysis at atmospheric pressure between 700 and 900{degree}C. It was found that the reduction reactions are always faster than oxidation reactions; reaction temperature and particle size do not significantly affect the reaction performance of CuO/bentonite. Multicycle CLC tests conducted in a high-pressure flow reactor showed stable reactivity for production of CO{sub 2} from fuel gas at 800 and 900{degree}C and full consumption of hydrogen during the reaction. Results of the tapered element oscillating microbalance showed a negative effect of pressure on the global rates of reduction-oxidation reactions at higher fractional conversions. X-ray diffraction patterns confirmed the presence of CuO in the bulk phase of the oxidized sample. Electron microanalysis showed significant morphology changes of reacted CuO/bentonite samples after the 10 oxidation-reduction cycles above 700{degree}C in an atmospheric thermogravimetric analyzer. The nanostructured CuO-BHA carrier also showed excellent stability and, in comparison to the CuO/bentonite system, slightly accelerated redox kinetics albeit at the expense of significantly increased complexity of manufacturing. Overall, both types of CuO carriers exhibited excellent reaction performance and thermal stability for the CLC process at 700-900{degree}C. 48 refs., 12 figs., 8 tabs.

  13. Chemical-looping Combustion of Coal-derived Synthesis Gas Over Copper Oxide Oxygen Carriers

    SciTech Connect

    Tian, Hanjing; Chaudhari, K P; Simonyi, Thomas; Poston, J A; Liu, Tengfei; Sanders, Tom; Veser, Goetz; Siriwardane, R V

    2008-11-01

    CuO/bentonite and CuO-BHA nanocomposites were studied as oxygen carriers in chemical-looping combustion (CLC) of simulated synthesis gas. Global reaction rates of reduction and oxidation, as the function of reaction conversion, were calculated from 10-cycle oxidation/reduction tests utilizing thermogravimetric analysis at atmospheric pressure between 700 and 900 °C. It was found that the reduction reactions are always faster than oxidation reactions; reaction temperature and particle size do not significantly affect the reaction performance of CuO/bentonite. Multicycle CLC tests conducted in a high-pressure flow reactor showed stable reactivity for production of CO2 from fuel gas at 800 and 900 °C and full consumption of hydrogen during the reaction. Results of the tapered element oscillating microbalance showed a negative effect of pressure on the global rates of reduction-oxidation reactions at higher fractional conversions. X-ray diffraction patterns confirmed the presence of CuO in the bulk phase of the oxidized sample. Electron microanalysis showed significant morphology changes of reacted CuO/bentonite samples after the 10 oxidation-reduction cycles above 700 °C in an atmospheric thermogravimetric analyzer. The nanostructured CuO-BHA carrier also showed excellent stability and, in comparison to the CuO/bentonite system, slightly accelerated redox kinetics albeit at the expense of significantly increased complexity of manufacturing. Overall, both types of CuO carriers exhibited excellent reaction performance and thermal stability for the CLC process at 700-900 °C.

  14. Solar Thermal Conversion of Biomass to Synthesis Gas: Cooperative Research and Development Final Report, CRADA Number CRD-09-00335

    SciTech Connect

    Netter, J.

    2013-08-01

    The CRADA is established to facilitate the development of solar thermal technology to efficiently and economically convert biomass into useful products (synthesis gas and derivatives) that can replace fossil fuels. NREL's High Flux Solar Furnace will be utilized to validate system modeling, evaluate candidate reactor materials, conduct on-sun testing of the process, and assist in the development of solar process control system. This work is part of a DOE-USDA 3-year, $1M grant.

  15. Bioconversion of coal-derived synthesis gas to liquid fuels. Final report, September 29, 1992--December 27, 1994

    SciTech Connect

    Jain, M.K.; Worden, R.M.; Grethlein, H.E.

    1995-01-15

    The proposed research project consists of an integrated, two-stage fermentation and a highly energy-efficient product separation scheme. In the first fermentation, Butyribacterium methylotrophicum converts carbon monoxide (CO) into butyric acid and acetic acids which are then converted into butanol, ethanol, and a small amount of acetone in the second stage fermentation by Clostridium acetobutylicum. An advanced separation system process, based on pervaporation, removes the alcohols from the fermentation broth as they are formed, along with some of the hydrogen sulfide (H{sub 2}S), to minimize possible inhibition of the fermentations. This bioconversion process offers a critical advantage over conventional, catalytic processes for synthesis gas conversion: the microorganisms are several orders of magnitude more sulfur tolerant than metallic catalysts. The catalysts require sulfur removal to the parts per million level, while the microorganisms are unaffected by H{sub 2}S and carbonyl sulfide (COS) at one part per hundred--roughly the composition of sulfur in raw synthesis gas. During the two-year course of this project, the following major objectives have been accomplished: demonstrated long-term cell recycle of continuous fermentation of synthesis gas; demonstrated cell immobilization of Butyribacterium methylotrophicum; identified trickle-bed reactor as a viable alternative fermentation method; modulated metabolic pathways to increase C4 formation during synthesis gas fermentation; recovered carbon and electrons from H{sub 2} and CO{sub 2} with pathway modulation for increased C4 production; developed bacterial strains with improved selectivity for butyrate fermentation; demonstrated two-stage CO to alcohol fermentation; and concentrated alcohol from solventogenic fermentation by pervaporation.

  16. Bioconversion of coal-derived synthesis gas to liquid fuels. Annual report, September 29, 1992--September 28, 1993

    SciTech Connect

    Jain, M.K.; Worden, R.M.; Grethlein, H.E.

    1993-10-21

    The overall objective of the project is to develop and optimize a two-stage fermentation process for the conversion of coal derived synthesis gas in an mixture of alcohols. The goals include the development of superior strains with high product tolerance and productivity, optimization of process conditions for high volumetric productivity and product concentrations, integration and optimization of two stage syngas fermentation, evaluation of bioreactor configurations for enhanced mass transfer, evaluation of syngas conversion by a culture of Butyribacterium methyltrophicum and Clostridium acetobutylicum, development of a membrane based pervaporation system for in situ removal of alcohols, and development of a process for reduction of carbon and electron loss. The specific goals for year one (September 1992 - September 1993) were (1) development of a project work plan, (2) development of superior CO-utilizing strains, (3) optimization of process conditions for conversion of synthesis gas to a mixture of acids in a continuously stirred reactor (CSTR), (4) evaluation of different bioreactor configurations for maximization of mass transfer of synthesis gas, (5) development of a membrane based pervaporation system, and (6) reduction of carbon and electron loss via H{sub 2}CO{sub 2} fermentation. Experimentation and progress toward these goals are described in this report.

  17. High-temperature slurry reactors for synthesis gas reactions. 1: Liquid thermal stability

    SciTech Connect

    Roberts, G.W.; Marquez, M.A.; McCutchen, M.S.; Haney, C.A.; Shin, I.D.

    1997-10-01

    The use of slurry reactors has been limited to reactions that take place at temperatures below about 573 K because many of the liquids that have been used to suspend the solid catalyst are not stable above this temperature. The thermal stability of a number of organic liquids was evaluated at temperatures between 648 and 698 K and at H{sub 2} partial pressures of about 7 MPa. Certain saturated and partially-saturated, fused-ring compounds with no alkyl groups or bridges are quite stable at these conditions. Of the compounds tested, tetrahydronaphthalene, tetrahydroquinoline, and decahydronaphthalene were the most stable. Analysis of the liquids at the end of the thermal stability evaluation supports some speculation concerning possible degradation reactions. The motivation for this research was the desire to synthesize higher (C{sub 2}{minus}C{sub 6}) alcohols in a slurry reactor from a mixture of carbon monoxide (CO) and hydrogen (H{sub 2}), so-called synthesis gas. Alcohols such as isobutanol and isoamyl alcohol could be a source of the branched olefins that are needed to produce octane enhancers such as methyl tert-butyl ether (MTBE) and tert-amyl methyl ether (TAME).

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

    SciTech Connect

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

    1995-12-31

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

  19. Kinetic Studies on Fermentative Production of Biofuel from Synthesis Gas Using Clostridium ljungdahlii

    PubMed Central

    Mohamed, Abdul Rahman; Najafpour, Ghasem D.; Younesi, Habibollah; Uzir, Mohamad Hekarl

    2014-01-01

    The intrinsic growth, substrate uptake, and product formation biokinetic parameters were obtained for the anaerobic bacterium, Clostridium ljungdahlii, grown on synthesis gas in various pressurized batch bioreactors. A dual-substrate growth kinetic model using Luong for CO and Monod for H2 was used to describe the growth kinetics of the bacterium on these substrates. The maximum specific growth rate (μmax = 0.195 h−1) and Monod constants for CO (Ks,CO = 0.855 atm) and H2 (Ks,H2 = 0.412 atm) were obtained. This model also accommodated the CO inhibitory effects on cell growth at high CO partial pressures, where no growth was apparent at high dissolved CO tensions (PCO∗ > 0.743 atm). The Volterra model, Andrews, and modified Gompertz were, respectively, adopted to describe the cell growth, substrate uptake rate, and product formation. The maximum specific CO uptake rate (qmax = 34.364 mmol/gcell/h), CO inhibition constant (KI = 0.601 atm), and maximum rate of ethanol (Rmax = 0.172 mmol/L/h at PCO = 0.598 atm) and acetate (Rmax = 0.096 mmol/L/h at PCO = 0.539 atm) production were determined from the applied models. PMID:24672390

  20. Ultraviolet-gas phase and -photocatalytic synthesis from CO and NH3.

    PubMed

    Hubbard, J S; Voecks, G E; Hobby, G L

    1975-08-05

    The major photoproduct obtained on irradiation of gaseous NH3 and CO mixtures is ammonium cyanate; lesser amounts of urea, biurea, biuret semi-carbazide, formamide and cyanide were observed. The formation of the major gas phase photolysis product may be rationalized by the following reaction sequence: (see article). Urea is probably formed from NH4NCO in a thermal reaction while formamide may result from the disproportionation of NH2CO. Photocatalytic syntheses of 14C-urea, -formamide, and -formadehyde are effected by irradiation of 14CO and NH3 in the presence of Vycor, silica gel, or volcanic ash shale surfaces. These syntheses are catalyzed by ultraviolet wavelengths longer than those absorbed by the gaseous reactants. The syntheses are also effected when the surface material is first irradiated in the presence of CO followed by a dark incubation with NH3. Apparently, the initiating step is a light dependent formation of a reactive form of CO on the surface. A discussion is given on the possible contribution of these reactions to the abiotic synthesis of organic nitrogen compounds on Mars, on the primitive Earth and in interstellar space.

  1. High pressure synthesis gas conversion. Task 2: Determination of maximum operating pressure

    SciTech Connect

    Not Available

    1993-05-01

    The purpose of this research project was to build and test a high pressure fermentation system for the production of ethanol from synthesis gas. The fermenters, pumps, controls, and analytical system were procured or fabricated and assembled in our laboratory. This system was then used to determine the effects of high pressure on growth and ethanol production by C. ljungdahlil. The limits of cell concentration and mass transport relationships were found in CSTR and immobilized cell reactors (ICR). The minimum retention times and reactor volumes were found for ethanol production in these reactors. The purpose of this report was to present the results of high pressure experiments aimed at determining the maximum operating pressure of C. ljungdahlil. Preliminary experiments carried out in approaching the pressure maximum are presented, as well as experimental results at the maximum pressure of 150 psig. This latter pressure was the maximum operating pressure when using the defined medium of Phillips et al., and is expected to change if alternative media are employed.

  2. Reforming of biogas to synthesis gas by a rotating arc plasma at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Chung, Woo-Jae; Park, Hyun-Woo; Liu, Jing-Lin; Park, Dong-Wha

    2015-09-01

    In order to produce synthesis gas, reforming of biogas composed with 60 percent for CH4 and 40 percent for CO2 was performed by a novel rotating arc plasma process. The effect of O2/CH4 ratio on the conversion, syngas composition and energy cost was investigated to evaluate the performance of proposed system compared with conventional gliding arc plasma process. When the O2/CH4 ratio was increased from 0.4 to 0.9, the conversions of CH4 and O2 increased up to 97.5 percent and 98.8 percent, respectively, while CO2 conversion was almost constant to be 38.6 percent. This is due to more enhance the partial oxidation of CH4 to CO and H2 than that of dry reforming by increasing the O2/CH4 ratio. In this work, energy cost of 32 kJ/mol was achieved with high syngas composition of 71 percent using pure O2 as oxidant reactant. These are lower than those of different arc plasma processes (energy cost of 122 - 1870 kJ/mol) such as spark, spark-shade and gliding arc plasma. Because, this rotating arc plasma can remain in a long arc length and a large volume of plasma with constant arc length mode.

  3. Equipment Design and Cost Estimation for Small Modular Biomass Systems, Synthesis Gas Cleanup, and Oxygen Separation Equipment; Task 2: Gas Cleanup Design and Cost Estimates -- Wood Feedstock

    SciTech Connect

    Nexant Inc.

    2006-05-01

    As part of Task 2, Gas Cleanup and Cost Estimates, Nexant investigated the appropriate process scheme for treatment of wood-derived syngas for use in the synthesis of liquid fuels. Two different 2,000 metric tonne per day gasification schemes, a low-pressure, indirect system using the gasifier, and a high-pressure, direct system using gasification technology were evaluated. Initial syngas conditions from each of the gasifiers was provided to the team by the National Renewable Energy Laboratory. Nexant was the prime contractor and principal investigator during this task; technical assistance was provided by both GTI and Emery Energy.

  4. Bioconversion of coal-derived synthesis gas to liquid fuels. Final technical report, September 1, 1990--August 31, 1991

    SciTech Connect

    Jain, M.K.

    1991-12-31

    The use of coal-derived synthesis gas as an industrial feedstock for production of fuels and chemicals has become an increasingly attractive alternative to present petroleum-based chemicals production. However, one of the major limitations in developing such a process is the required removal of catalyst poisons such as hydrogen sulfide (H{sub 2}S), carbonyl sulfide (COS), and other trace contaminants from the synthesis gas. Purification steps necessary to remove these are energy intensive and add significantly to the production cost, particularly for coals having a high sulfur content such as Illinois coal. A two-stage, anaerobic bioconversion process requiring little or no sulfur removal is proposed, where in the first stage the carbon monoxide (CO) gas is converted to butyric and acetic acids by the CO strain of Butyribacterium methylotrophicum. In the second stage, these acids along with the hydrogen (H{sub 2}) gas are converted to butanol, ethanol, and acetone by an acid utilizing mutant of Clostridium acetobutylicum. 18 figs., 18 tabs.

  5. Study on the synthesis of Indium Tinoxide (ITO) nanomaterial using sol gel process and its potential for CO gas detection

    NASA Astrophysics Data System (ADS)

    Wiranto, Goib; Idayanti, Novrita; Retnaningsih, Lilis

    2016-11-01

    This paper described the synthesis of doped and undoped nanomaterial Indium Tinoxide (ITO) using sol-gel process with the base materials from Indium Nitride (In(NO3)) and Tin Chloride (SnCl4). Doping was done using Palladium Chloride (PdCl), with the molar ratio of 90:10 and 70:30, respectively. Physical characteristics of the nanocrystallites were examined using SEM, EDS, XRD, and FTIR, whereas its resistivity was tested agaist CO gas. The result showed that the ITO powders have a crystal size smaller than 100 nm, with a cubic crystal structure (byxbite type), and having strong molecular bonds for In-O-In and Sn-O-Sn. The response to CO gases showed a decreasing resistivity with increasing CO gas concentration, showing its potential for gas sensor application.

  6. Gas-Phase Synthesis of Gold- and Silica-Coated Nanoparticles

    NASA Astrophysics Data System (ADS)

    Boies, Adam Meyer

    2011-12-01

    Composite nanoparticles consisting of separate core-shell materials are of interest for a variety of biomedical and industrial applications. By combining different materials at the nanoscale, particles can exhibit enhanced or multi-functional behavior such as plasmon resonance combined with superparamagnetism. Gas-phase nanoparticle synthesis processes are promising because they can continuously produce particles with high mass-yield rates. In this dissertation, new methods are investigated for producing gas-phase coatings of nanoparticles in an "assembly-line" fashion. Separate processes are developed to create coatings from silica and gold that can be used with a variety of core-particle chemistries. A photoinduced chemical vapor deposition (photo-CVD) method is used to produce silica coatings from tetraethyl orthosilicate (TEOS) on the surface of nanoparticles (diameter ˜5--70 nm). Tandem differential mobility analysis (TDMA) of the process demonstrates that particle coatings can be produced with controllable thicknesses (˜1--10 nm) by varying system parameters such as precursor flow rate. Electron microscopy and infrared spectroscopy confirm that the photo-CVD films uniformly coat the particles and that the coatings are silica. In order to describe the coating process a chemical mechanism is proposed that includes gas-phase, surface and photochemical reactions. A chemical kinetics model of the mechanism indicates that photo-CVD coating proceeds primarily through the photodecomposition of TEOS which removes ethyl groups, thus creating activated TEOS species. The activated TEOS then adsorbs onto the surface of the particle where a series of subsequent reactions remove the remaining ethyl groups to produce a silica film with an open site for further attachment. The model results show good agreement with the experimentally measured coating trends, where increased TEOS flow increases coating thickness and increased nitrogen flow decreases coating thickness. Gold

  7. Testosterone delays vascular smooth muscle cell senescence and inhibits collagen synthesis via the Gas6/Axl signaling pathway.

    PubMed

    Chen, Yan-qing; Zhao, Jing; Jin, Cheng-wei; Li, Yi-hui; Tang, Meng-xiong; Wang, Zhi-hao; Zhang, Wei; Zhang, Yun; Li, Li; Zhong, Ming

    2016-06-01

    Testosterone deficiency is associated with a higher incidence of cardiovascular diseases in men. However, its effect on cell senescence, which plays a causal role in vascular aging, remains unclear. Here, we tested the hypothesis that testosterone alleviated vascular smooth muscle cell (VSMC) senescence and collagen synthesis via growth arrest-specific protein 6 (Gas6)/Axl- and Akt/FoxO1a-dependent pathways. Testosterone significantly ameliorated angiotensin II-induced VSMC senescence and collagen overexpression. In addition, testosterone inhibited angiotensin II-induced matrix metalloproteinase-2 (MMP-2) activity, which played a pivotal role in facilitating age-related collagen deposition. Testosterone increased the expression of tissue inhibitor of metalloproteinase-2 but decreased the expression of MMP-2 and membrane type-1 metalloproteinase which contributed to increase MMP-2 activity. The effects on VSMCs senescence and collagen synthesis were mediated by restoration of angiotensin II-induced downregulation of Gas6 and Axl expression and a subsequent reduction of Akt and FoxO1a phosphorylation. The effects of testosterone were reversed by a Gas6 blocker, Axl-Fc, and a specific inhibitor of Axl, R428. Treatment of VSMCs with PI3K inhibitor LY294002 abrogated the downregulating effect of testosterone on MMP-2 activity. Furthermore, when FoxO1a expression was silenced by using a specific siRNA, the inhibitory effect of testosterone on MMP-2 activity was revered as well, that indicated this process was Akt/FoxO1a dependence. Taken together, Gas6/Axl and Akt/FoxO1a were involved in protective effects of testosterone on VSMCs senescence and collagen synthesis. Our results provide a novel mechanism underlying the protective effect of testosterone on vascular aging and may serve as a theoretical basis for testosterone replacement therapy.

  8. Chemical-looping combustion of simulated synthesis gas using nickel oxide oxygen carrier supported on bentonite

    SciTech Connect

    Siriwardane, R.V.; Chaudhari, K.; Poston, J.A.; Zinn, A.; Simonyi, T.; Robinson, C.

    2007-05-01

    Chemical-looping combustion (CLC) is a combustion technology for clean and efficient utilization of fossil fuels for energy production. This process which produces sequestration ready CO2 systems is a promising technology to be utilized with coal gasification systems. In the present work, chemical-looping combustion has been studied with an oxygen carrier, NiO/bentonite (60 wt % NiO) for the gasification systems utilizing simulated synthesis gas. Global reaction rates of reduction and oxidation as a function of conversion were calculated for oxidation-reduction cycles utilizing the thermogravimetric analysis (TGA) data on multicycle tests conducted with NiO/bentonite at atmospheric pressure between 700 and 900 °C. The rate of reduction increased slightly with an increase in temperature, while the rate of oxidation decreased at 900 °C. The effect of particle size of the oxygen carrier on CLC was studied for the particle size between 20 and 200 mesh. The rates of reactions depended on the particle size of the oxygen carrier. The smaller the particle size, the higher the reaction rates. The multicycle CLC tests conducted in a high-pressure flow reactor showed stable reactivity for the production of CO2 from fuel gas at 800 and 900 °C and full consumption of hydrogen during the reaction. The data from a one cycle test on the effect of the pressure on the performance with NiO/bentonite utilizing the tapered element oscillating microbalance (TEOM) showed a positive effect of the pressure on the global rates of reduction-oxidation reactions at higher fractional conversions. The X-ray diffraction (XRD) analysis confirmed the presence of the NiO phase in NiO/bentonite with the oxidized sample in the highpressure reactor and Ni phase with the reduced sample. The presence of a small amount of NiO in the reduced sample detected by X-ray photoelectron spectroscopy (XPS) may be due to its exposure to air during sample transfer from the reactor to XPS. Scanning electron

  9. Status and future opportunities for conversion of synthesis gas to liquid energy fuels: Final report

    SciTech Connect

    Mills, G

    1993-05-01

    The manufacture of liquid energy fuels from syngas (a mixture of H{sub 2} and CO, usually containing CO{sub 2}) is of growing importance and enormous potential because: (1) Abundant US supplies of coal, gas, and biomass can be used to provide the needed syngas. (2) The liquid fuels produced, oxygenates or hydrocarbons, can help lessen environmental pollution. Indeed, oxygenates are required to a significant extent by the Clean Air Act Amendments (CAAA) of 1990. (3) Such liquid synfuels make possible high engine efficiencies because they have high octane or cetane ratings. (4) There is new, significantly improved technology for converting syngas to liquid fuels and promising opportunities for further improvements. This is the subject of this report. The purpose of this report is to provide an account and evaluative assessment of advances in the technology for producing liquid energy fuels from syngas and to suggest opportunities for future research deemed promising for practical processes. Much of the improved technology for selective synthesis of desired fuels from syngas has resulted from advances in catalytic chemistry. However, novel process engineering has been particularly important recently, utilizing known catalysts in new configurations to create new catalytic processes. This report is an update of the 1988 study Catalysts for Fuels from Syngas: New Directions for Research (Mills 1988), which is included as Appendix A. Technology for manufacture of syngas is not part of this study. The manufacture of liquid synfuels is capital intensive. Thus, in evaluating advances in fuels technology, focus is on the potential for improved economics, particularly on lowering plant investment costs. A second important criteria is the potential for environmental benefits. The discussion is concerned with two types of hydrocarbon fuels and three types of oxygenate fuels that can be synthesized from syngas. Seven alternative reaction pathways are involved.

  10. Status and future opportunities for conversion of synthesis gas to liquid energy fuels: Final report

    SciTech Connect

    Mills, G. . Center for Catalytic Science and Technology)

    1993-05-01

    The manufacture of liquid energy fuels from syngas (a mixture of H[sub 2] and CO, usually containing CO[sub 2]) is of growing importance and enormous potential because: (1) Abundant US supplies of coal, gas, and biomass can be used to provide the needed syngas. (2) The liquid fuels produced, oxygenates or hydrocarbons, can help lessen environmental pollution. Indeed, oxygenates are required to a significant extent by the Clean Air Act Amendments (CAAA) of 1990. (3) Such liquid synfuels make possible high engine efficiencies because they have high octane or cetane ratings. (4) There is new, significantly improved technology for converting syngas to liquid fuels and promising opportunities for further improvements. This is the subject of this report. The purpose of this report is to provide an account and evaluative assessment of advances in the technology for producing liquid energy fuels from syngas and to suggest opportunities for future research deemed promising for practical processes. Much of the improved technology for selective synthesis of desired fuels from syngas has resulted from advances in catalytic chemistry. However, novel process engineering has been particularly important recently, utilizing known catalysts in new configurations to create new catalytic processes. This report is an update of the 1988 study Catalysts for Fuels from Syngas: New Directions for Research (Mills 1988), which is included as Appendix A. Technology for manufacture of syngas is not part of this study. The manufacture of liquid synfuels is capital intensive. Thus, in evaluating advances in fuels technology, focus is on the potential for improved economics, particularly on lowering plant investment costs. A second important criteria is the potential for environmental benefits. The discussion is concerned with two types of hydrocarbon fuels and three types of oxygenate fuels that can be synthesized from syngas. Seven alternative reaction pathways are involved.

  11. Ethanol synthesis and water gas shift over bifunctional sulfide catalysts. Final technical progress report, September 12, 1991--December 11, 1994

    SciTech Connect

    Klier, K.; Herman, R.G.; Deemer, M.; Richards-Babb, M.; Carr, T.

    1995-07-01

    The objective of this research was to investigate sulfur-resistant catalysts for the conversion of synthesis gas having H{sub 2}/CO {le} 1 into C{sub 1}--C{sub 4} alcohols, especially ethanol, by a highly selective and efficient pathway, while also promoting the water gas shift reaction (WGSR). The catalysts chosen are bifunctional, base-hydrogenation, sulfur-tolerant transition metal sulfides with heavy alkali, e.g. Cs{sup +}, promoter dispersed on their surfaces. The modes of activation of H{sub 2} and CO on MoS{sub 2} and alkali-doped MoS{sub 2} were considered, and computational analyses of the thermodynamic stability of transition metal sulfides and of the electronic structure of these sulfide catalysts were carried out. In the preparation of the cesium-promoted MoS{sub 2} catalysts, a variety of preparation methods using CsOOCH were examined. In all cases, doping with CsOOCH led to a lost of surface area. The undoped molybdenum disulfide catalyst only produced hydrocarbons. Cs-doped MoS{sub 2} catalysts all produced linear alcohols, along with smaller amounts of hydrocarbons. With a 20 wt% CsOOCH/MoS{sub 2} catalyst, temperature, pressure, and flow rate dependences of the synthesis reactions were investigated in the presence and absence of H{sub 2}S in the H{sub 2}/CO = 1/1 synthesis gas during short term testing experiments. It was shown that with a carefully prepared 10 wt% CsOOCH/MoS{sub 2} catalyst, reproducible and high alcohol synthesis activity could be obtained. For example, at 295 C with H{sub 2}/CO = 1 synthesis gas at 8.3 MPa and with GHSV = 7,760 l/kg cat/hr, the total alcohol space time yield was ca 300 g/kg cat/hr (accompanied with a hydrocarbon space time yield of ca 60 g/kg cat/hr). Over a testing period of ca 130 hr, no net deactivation of the catalyst was observed. 90 refs., 82 figs., 14 tabs.

  12. Synthesis gas production with an adjustable H{sub 2}/CO ratio through the coal gasification process: effects of coal ranks and methane addition

    SciTech Connect

    Yan Cao; Zhengyang Gao; Jing Jin; Hongchang Zhou; Marten Cohron; Houying Zhao; Hongying Liu; Weiping Pan

    2008-05-15

    Direct production of synthesis gas using coal as a cheap feedstock is attractive but challenging due to its low H{sub 2}/CO ratio of generated synthesis gas. Three typical U.S. coals of different ranks were tested in a 2.5 in. coal gasifier to investigate their gasification reactivity and adjustability on H{sub 2}/CO ratio of generated synthesis gas with or without the addition of methane. Tests indicated that lower-rank coals (lignite and sub-bituminous) have higher gasification reactivity than bituminous coals. The coal gasification reactivity is correlated to its synthesis-gas yield and the total percentage of H{sub 2} and CO in the synthesis gas, but not to the H{sub 2}/CO ratio. The H{sub 2}/CO ratio of coal gasification was found to be correlated to the rank of coals, especially the H/C ratio of coals. Methane addition into the dense phase of the pyrolysis and gasification zone of the cogasification reactor could make the best use of methane in adjusting the H{sub 2}/CO ratio of the generated synthesis gas. The maximum methane conversion efficiency, which was likely correlated to its gasification reactivity, could be achieved by 70% on average for all tested coals. The actual catalytic effect of generated coal chars on methane conversion seemed coal-dependent. The coal-gasification process benefits from methane addition and subsequent conversion on the adjustment of the H{sub 2}/CO ratio of synthesis gas. The methane conversion process benefits from the use of coal chars due to their catalytic effects. This implies that there were likely synergistic effects on both. 25 refs., 3 figs., 3

  13. The economical production of alcohol fuels from coal-derived synthesis gas. Quarterly technical progress report No. 5, October 1, 1992--December 31, 1992

    SciTech Connect

    Not Available

    1993-01-01

    Two base case flow sheets have now been prepared. In the first, which was originally presented in TPR4, a Texaco gasifier is used. Natural gas is also burned in sufficient quantity to increase the hydrogen to carbon monoxide ratio of the synthesis gas to the required value of 1. 1 for alcohol synthesis. Acid gas clean up and sulfur removal are accomplished using the Rectisol process followed by the Claus and Beavon processes. About 10% of the synthesis gas is sent to a power generation unit in order to produce electric power, with the remaining 90% used for alcohol synthesis. For this process, the estimated installed cost is $474.2 mm. The estimated annual operating costs are $64.5 MM. At a price of alcohol fuels in the vicinity of $1. 00/gal, the pay back period for construction of this plant is about four years. The details of this case, called Base Case 1, are presented in Appendix 1. The second base case, called Base Case 2, also has a detailed description and explanation in Appendix 1. In Base Case 2, a Lurgi Gasifier is used. The motivation for using a Lurgi Gasifier is that it runs at a lower temperature and pressure and, therefore, produces by-products such as coal liquids which can be sold. Based upon the economics of joint production, discussed in Technical Progress Report 4, this is a necessity. Since synthesis gas from natural gas is always less expensive to produce than from coal, then alcohol fuels will always be less expensive to produce from natural gas than from coal. Therefore, the only way to make coal- derived alcohol fuels economically competitive is to decrease the cost of production of coal-derived synthesis gas. one method for accomplishing this is to sell the by-products from the gasification step. The details of this strategy are discussed in Appendix 3.

  14. Interaction of iron-copper mixed metal oxide oxygen carriers with simulated synthesis gas derived from steam gasification of coal

    SciTech Connect

    Siriwardane, Ranjani V.; Ksepko, Ewelina; Tian, Hanging

    2013-01-01

    The objective of this work was to prepare supported bimetallic Fe–Cu oxygen carriers and to evaluate their performance for the chemical-looping combustion (CLC) process with simulated synthesis gas derived from steam gasification of coal/air. Ten-cycle CLC tests were conducted with Fe–Cu oxygen carriers in an atmospheric thermogravimetric analyzer utilizing simulated synthesis gas derived from the steam gasification of Polish Janina coal and Illinois #6 coal as fuel. The effect of temperature on reaction rates, chemical stability, and oxygen transport capacity were determined. Fractional reduction, fractional oxidation, and global rates of reactions were calculated from the thermogravimetric analysis (TGA) data. The supports greatly affected reaction performance. Data showed that reaction rates and oxygen capacities were stable during the 10-cycle TGA tests for most Fe–Cu/support oxygen carriers. Bimetallic Fe–Cu/support oxygen carriers showed higher reduction rates than Fe-support oxygen carriers. The carriers containing higher Cu content showed better stabilities and better reduction rates. An increase in temperature from 800 °C to 900 °C did not have a significant effect on either the oxygen capacity or the reduction rates with synthesis gas derived from Janina coal. Oxidation reaction was significantly faster than reduction reaction for all supported Fe–Cu oxygen carriers. Carriers with higher Cu content had lower oxidation rates. Ten-cycle TGA data indicated that these oxygen carriers had stable performances at 800–900 °C and might be successfully used up to 900 °C for coal CLC reaction in the presence of steam.

  15. Alternative fuels and chemicals from synthesis gas. Quarterly status report number 2, 1 January--31 March 1995

    SciTech Connect

    1995-12-31

    The overall objectives of this program are to investigate potential technologies for the conversion of synthesis gas to oxygenated and hydrocarbon fuels and industrial chemicals, and to demonstrate the most promising technologies at DOE`s LaPorte, Texas, Slurry Phase Alternative Fuels Development Unit. Results are discussed for the following tasks: liquid phase hydrodynamic run; catalyst activation with CO; new processes for DME (dehydration catalyst screening runs, and experiments using Robinson-Mahoney basket internal and pelletized catalysts); new fuels from DME; and new processes for alcohols and oxygenated fuel additives.

  16. Gas atomization synthesis of refractory or intermetallic compounds and supersaturated solid solutions

    DOEpatents

    Anderson, Iver E.; Lograsso, Barbara K.; Ellis, Timothy W.

    1994-01-01

    A metallic melt is atomized using a high pressure atomizing gas wherein the temperature of the melt and the composition of the atomizing gas are selected such that the gas and melt react in the atomization spray zone to form a refractory or intermetallic compound in the as-atomized powder particles. A metallic melt is also atomized using a high pressure atomizing gas mixture gas wherein the temperature of the melt and the ratio of a reactive gas to a carrier gas are selected to form powder particles comprising a supersaturated solid solution of the atomic species of the reactive gas in the particles. The powder particles are then heat treated to precipitate dispersoids in-situ therein to form a dispersion strengthened material.

  17. Gas atomization synthesis of refractory or intermetallic compounds and supersaturated solid solutions

    DOEpatents

    Anderson, I.E.; Lograsso, B.K.; Ellis, T.W.

    1994-11-29

    A metallic melt is atomized using a high pressure atomizing gas wherein the temperature of the melt and the composition of the atomizing gas are selected such that the gas and melt react in the atomization spray zone to form a refractory or intermetallic compound in the as-atomized powder particles. A metallic melt is also atomized using a high pressure atomizing gas mixture gas wherein the temperature of the melt and the ratio of a reactive gas to a carrier gas are selected to form powder particles comprising a supersaturated solid solution of the atomic species of the reactive gas in the particles. The powder particles are then heat treated to precipitate dispersoids in-situ therein to form a dispersion strengthened material. 9 figures.

  18. Continuous gas/liquid–liquid/liquid flow synthesis of 4-fluoropyrazole derivatives by selective direct fluorination

    PubMed Central

    Breen, Jessica R; Yufit, Dmitrii S; Howard, Judith A K; Fray, Jonathan; Patel, Bhairavi

    2011-01-01

    Summary 4-Fluoropyrazole systems may be prepared by a single, sequential telescoped two-step continuous gas/liquid–liquid/liquid flow process from diketone, fluorine gas and hydrazine starting materials. PMID:21915207

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

    SciTech Connect

    Anthony, R.G.; Akgerman, A.

    1993-02-01

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

  20. Gas-phase synthesis of hydrodiphenylcyclopropenylium via nonclassical Favorskii rearrangement from alkali-cationized alpha,alpha'-dibromodibenzyl ketone.

    PubMed

    Zhao, Zhi-Xiong; Wang, Hao-Yang; Xu, Chu; Guo, Yin-Long

    2010-09-15

    The gas-phase synthesis of hydrodiphenylcyclopropenylium from alkali-cationized alpha,alpha'-dibromodibenzyl ketone (1) via nonclassical Lewis-acid-induced Favorskii rearrangement has been studied by electrospray ionization/tandem mass spectrometry (ESI-MS/MS) and theoretical methods, showing that cations [1-Br](+) by debromination from 1 and 1.M(+)(M = Li or Na) by alkali-metal cationization of 1 could convert into the protonated diphenylcyclopropenone 2.H(+) by collision-induced dissociation in the gas phase. A concerted mechanism for the Lewis-acid-induced Favorskii rearrangement from alkali-metal-cationized alpha,alpha'-dibromodibenzyl ketone was proposed and studied, based on mass spectrometric results and theoretical methods.

  1. Synthesis Methods, Microscopy Characterization and Device Integration of Nanoscale Metal Oxide Semiconductors for Gas Sensing in Aerospace Applications

    NASA Technical Reports Server (NTRS)

    VanderWal, Randy L.; Berger, Gordon M.; Kulis, Michael J.; Hunter, Gary W.; Xu, Jennifer C.; Evans, Laura J.

    2009-01-01

    A comparison is made between SnO2, ZnO, and TiO2 single-crystal nanowires and SnO2 polycrystalline nanofibers for gas sensing. Both nanostructures possess a one-dimensional morphology. Different synthesis methods are used to produce these materials: thermal evaporation-condensation (TEC), controlled oxidation, and electrospinning. Advantages and limitations of each technique are listed. Practical issues associated with harvesting, purification, and integration of these materials into sensing devices are detailed. For comparison to the nascent form, these sensing materials are surface coated with Pd and Pt nanoparticles. Gas sensing tests, with respect to H2, are conducted at ambient and elevated temperatures. Comparative normalized responses and time constants for the catalyst and noncatalyst systems provide a basis for identification of the superior metal-oxide nanostructure and catalyst combination. With temperature-dependent data, Arrhenius analyses are made to determine an activation energy for the catalyst-assisted systems.

  2. Engineering Development of Ceramic Membrane Reactor System for Converting Natural Gas to Hydrogen and Synthesis Gas for Liquid Transportation Fuels

    SciTech Connect

    Air Products and Chemicals

    2008-09-30

    An Air Products-led team successfully developed ITM Syngas technology from the concept stage to a stage where a small-scale engineering prototype was about to be built. This technology produces syngas, a gas containing carbon monoxide and hydrogen, by reacting feed gas, primarily methane and steam, with oxygen that is supplied through an ion transport membrane. An ion transport membrane operates at high temperature and oxygen ions are transported through the dense membrane's crystal lattice when an oxygen partial pressure driving force is applied. This development effort solved many significant technical challenges and successfully scaled-up key aspects of the technology to prototype scale. Throughout the project life, the technology showed significant economic benefits over conventional technologies. While there are still on-going technical challenges to overcome, the progress made under the DOE-funded development project proved that the technology was viable and continued development post the DOE agreement would be warranted.

  3. Equipment Design and Cost Estimation for Small Modular Biomass Systems, Synthesis Gas Cleanup, and Oxygen Separation Equipment; Task 2: Gas Cleanup Design and Cost Estimates -- Black Liquor Gasification

    SciTech Connect

    Nexant Inc.

    2006-05-01

    As part of Task 2, Gas Cleanup and Cost Estimates, Nexant investigated the appropriate process scheme for removal of acid gases from black liquor-derived syngas for use in both power and liquid fuels synthesis. Two 3,200 metric tonne per day gasification schemes, both low-temperature/low-pressure (1100 deg F, 40 psi) and high-temperature/high-pressure (1800 deg F, 500 psi) were used for syngas production. Initial syngas conditions from each of the gasifiers was provided to the team by the National Renewable Energy Laboratory and Princeton University. Nexant was the prime contractor and principal investigator during this task; technical assistance was provided by both GTI and Emery Energy.

  4. Ruthenium carbonyl catalyst supported on ceric oxide for preparation of olefins from synthesis gas

    DOEpatents

    Pierantozzi, Ronald

    1985-01-01

    A catalyst comprising a ruthenium carbonyl compound deposited on a cerium oxide-containing support material provides for the selective synthesis of low molecular weight olefinic hydrocarbons from mixtures of hydrogen and carbon monoxide.

  5. Preparation of olefins from synthesis gas using ruthenium supported on ceric oxide

    DOEpatents

    Pierantozzi, Ronald

    1985-01-01

    A catalyst comprising a ruthenium carbonyl compound deposited on a cerium oxide-containing support material provides for the selective synthesis of low molecular weight olefinic hydrocarbons from mixtures of hydrogen and carbon monoxide.

  6. Preparation of olefins from synthesis gas using ruthenium supported on ceric oxide

    DOEpatents

    Pierantozzi, R.

    1985-04-09

    A catalyst comprising a ruthenium carbonyl compound deposited on a cerium oxide-containing support material provides for the selective synthesis of low molecular weight olefinic hydrocarbons from mixtures of hydrogen and carbon monoxide.

  7. Ruthenium carbonyl catalyst supported on ceric oxide for preparation of olefins from synthesis gas

    DOEpatents

    Pierantozzi, R.

    1985-04-02

    A catalyst comprising a ruthenium carbonyl compound deposited on a cerium oxide-containing support material provides for the selective synthesis of low molecular weight olefinic hydrocarbons from mixtures of hydrogen and carbon monoxide.

  8. Bioconversion of coal derived synthesis gas to liquid fuels. Final quarterly technical progress report, July 1, 1993--September 30, 1993

    SciTech Connect

    Jain, M.K.; Worden, R.M.; Grethlein, H.

    1993-10-25

    The overall objective of the project is to develop an integrated two stage fermentation process for conversion of coal-derived synthesis gas to a mixture of alcohols. This is achieved in two steps. In the first step, Butyribacterium methylotrophicum converts carbon monoxide (CO) to butyric and acetic acids. Subsequent fermentation of the acids by Clostridium acetobutylicum leads to the production of butanol and ethanol. The tasks for this quarter were: (1) development/isolation of superior strains for fermentation of syngas, (2) optimization of process conditions for fermentation of syngas, (3) evaluation of bioreactor configuration for improved mass transfer of syngas, (4) development of a membrane-based pervaporation system, (5) optimization of process conditions for reducing carbon and electron loss by H{sub 2}-CO{sub 2} fermentation, and (6) synthesis gas fermentation in single-stage by co-culture. Progress is reported in isolation of CO utilizing anaerobic strains; investigating the product profile for the fermentation of syngas by B. methylotrophicum; and determining the effect of carbon monoxide on growth of C. acetobutylicum.

  9. Catalysts and process development for synthesis gas conversion to isobutylene. Quarterly report, July 1, 1991--September 30, 1991

    SciTech Connect

    Anthony, R.G.; Akgerman, A.

    1991-11-06

    The objectives of this project are to develop a new catalyst, the kinetics for this catalyst, simulate the performance of fixed bed trickle flow reactors, slurry flow reactors, and fixed bed gas phase reactors for conversion of a hydrogen-lean synthesis gas to isobutylene. The goals for this year were to recruit and organize the project team, complete the literature and patent searches, complete the management plan and other reporting requirements, complete the revision and upgrading of existing bench scale units for the project, and synthesize, characterize and evaluate the catalytic activity of zirconia prepared (1) by co-precipitation of zirconyl nitrate with ammonium hydroxide and (2) by preparing a hydrous zirconium oxide using the modified sol gel method developed at the Sandia National Laboratories followed by calcination. The same preparation procedure would be used to prepare supports for impregnation with thorium nitrate, a potassium salt and a sodium salt. The synthesis of new crystalline zirconates were to be attempted with the objective of producing new compositions of matter which might have higher activities and selectivities than zirconia. Substantial progress on reactor and kinetic models for slurry and trickle bed reactors was to be achieved. Accomplishments for the year are described.

  10. Partial oxidation of methane to synthesis gas using LnCoO{sub 3} perovskites as catalyst precursors

    SciTech Connect

    Lago, R.; Pena, M.A.; Fierro, J.L.G.

    1997-04-01

    In this work, a series of cobalt-containing perovskites LnCoO{sub 3} (Ln = La, Pr, Nd, Sm, and Gd) has been studied as catalyst precursors for the partial oxidation of methane to synthesis gas. All the perovskite precursors were prereduced in situ, producing cobalt metal finely dispersed over the rare earth sesquioxide support described here as Ln-Co-O. Of the catalyst tested, the system Gd-Co-O showed exceptionally better performance for CO and H{sub 2} production (with methane conversion of 73% and selectivities of 79 and 81% for CO and H{sub 2}, respectively, at 1009 K). The production of synthesis gas over the other catalysts decreased in the following order: Sm-Co-O {much_gt} Nd-Co-O > Pr-Co-O. The catalyst La-Co-O was active for methane combustion and only traces of CO and H{sub 2} were observed under the reaction conditions. Based on results obtained here, it is proposed that the deactivation of the catalysts Ln-Co-O by reoxidation of cobalt metal is related to the thermodynamic stability of the parent perovskite structure. The authors also present evidence that hydroxyl groups on the rare earth oxide, specially in the La-Co-O system, might make some contribution to the reoxidation of cobalt metal during the reaction via a reverse spillover process. 48 refs., 12 figs., 2 tabs.

  11. Thermodynamic-Controlled Gas Phase Process for the Synthesis of Nickel Nanoparticles of Adjustable Size and Morphology

    NASA Astrophysics Data System (ADS)

    Kauffeldt, Elena; Kauffeldt, Thomas

    2006-08-01

    Gas phase processes are a successful route for the synthesis of nano materials. Nickel particles are used in applications ranging from catalysis to nano electronics and energy storage. The application field defines the required particle size, morphology, crystallinity and purity. Nickel tetracarbonyl is the most promising precursor for the synthesis of high purity nickel particles. Due to the toxicity of this precursor and to obtain an optimal process control we developed a two-step flow type process. Nickel carbonyl and nickel particles are synthesized in a sequence of reactions. The particles are formed in a hot wall reactor at temperatures below 400°C in different gas compositions. Varying the process conditions enables the adjustment of the particle size in a range from 3 to 140 nm. The controllable crystalline habits are polycrystalline, single crystals or multiple twinned particles (MTP). Spectroscopic investigations show an excellent purity. We report about the process and first investigations of the properties of the synthesized nickel nanomaterial.

  12. Applied reaction dynamics: Efficient synthesis gas production via single collision partial oxidation of methane to CO on Rh(111)

    NASA Astrophysics Data System (ADS)

    Gibson, K. D.; Viste, M.; Sibener, S. J.

    2006-10-01

    Supersonic molecular beams have been used to determine the yield of CO from the partial oxidation of CH4 on a Rh(111) catalytic substrate, CH4+(1/2)O2→CO +2H2, as a function of beam kinetic energy. These experiments were done under ultrahigh vacuum conditions with concurrent molecular beams of O2 and CH4, ensuring that there was only a single collision for the CH4 to react with the surface. The fraction of CH4 converted is strongly dependent on the normal component of the incident beam's translational energy, and approaches unity for energies greater than ˜1.3eV. Comparison with a simplified model of the methane-Rh(111) reactive potential gives insight into the barrier for methane dissociation. These results demonstrate the efficient conversion of methane to synthesis gas, CO +2H2, are of interest in hydrogen generation, and have the optimal stoichiometry for subsequent utilization in synthetic fuel production (Fischer-Tropsch or methanol synthesis). Moreover, under the reaction conditions explored, no CO2 was detected, i.e., the reaction proceeded with the production of very little, if any, unwanted greenhouse gas by-products. These findings demonstrate the efficacy of overcoming the limitations of purely thermal reaction mechanisms by coupling nonthermal mechanistic steps, leading to efficient C-H bond activation with subsequent thermal heterogeneous reactions.

  13. Synthesis and Characterization of Cobalt Containing Nanoparticles on Alumina A Potential Catalyst for Gas to Liquid Fuels Production

    NASA Technical Reports Server (NTRS)

    Cowen, Jonathan; Hepp, Aloysius F.

    2016-01-01

    Fisher-Tröpsch synthesis (FTS) is a century-old gas-to-liquid (GTL) technology that commonly employs cobalt (Co, on an oxide support) or iron (supported or not) species catalysts. It has been well established that the activity of the Co catalyst depends directly upon the number of surface Co atoms. The addition of promoter (mainly noble) metals has been widely utilized to increase the fraction of Co that is available for surface catalysis. Direct synthesis of Co nanoparticles is a possible alternative approach; our preliminary synthesis and characterization efforts are described. Materials were characterized by various transmission microscopies and energy dispersive spectroscopy. Tri-n-octylphosphine oxide (TOPO) and dicobalt octacarbonyl were heated under argon to a temperature of 180 deg with constant stirring for 1 hr. Quenching the reaction in toluene produced Co-containing nanoparticles with a diameter of 5 to 10 nm. Alternatively, an alumina support (SBA-200 Al2O3) was added; the reaction was further stirred and the temperature was decreased to 140 deg to reduce the rate of further growth/ripening of the nucleated Co nanoparticles. A typical size of Co-containing NPs was also found to be in the range of 5 to 10 nm. This can be contrasted with a range of 50 to 200 nm for conventionally-produced Co-Al2O3 Fischer-Tröpsch catalysts. This method shows great potential for production of highly dispersed catalysts that are either supported or unsupported.

  14. Engineering high-performance Pd core-MgO porous shell nanocatalysts via heterogeneous gas-phase synthesis

    NASA Astrophysics Data System (ADS)

    Singh, Vidyadhar; Cassidy, Cathal; Abild-Pedersen, Frank; Kim, Jeong-Hwan; Aranishi, Kengo; Kumar, Sushant; Lal, Chhagan; Gspan, Christian; Grogger, Werner; Sowwan, Mukhles

    2015-08-01

    We report on the design and synthesis of high performance catalytic nanoparticles with a robust geometry via magnetron-sputter inert-gas condensation. Sputtering of Pd and Mg from two independent neighbouring targets enabled heterogeneous condensation and growth of nanoparticles with controlled Pd core-MgO porous shell structure. The thickness of the shell and the number of cores within each nanoparticle could be tailored by adjusting the respective sputtering powers. The nanoparticles were directly deposited on glassy carbon electrodes, and their catalytic activity towards methanol oxidation was examined by cyclic voltammetry. The measurements indicated that the catalytic activity was superior to conventional bare Pd nanoparticles. As confirmed by electron microscopy imaging and supported by density-functional theory (DFT) calculations, we attribute the improved catalytic performance primarily to inhibition of Pd core sintering during the catalytic process by the metal-oxide shell.We report on the design and synthesis of high performance catalytic nanoparticles with a robust geometry via magnetron-sputter inert-gas condensation. Sputtering of Pd and Mg from two independent neighbouring targets enabled heterogeneous condensation and growth of nanoparticles with controlled Pd core-MgO porous shell structure. The thickness of the shell and the number of cores within each nanoparticle could be tailored by adjusting the respective sputtering powers. The nanoparticles were directly deposited on glassy carbon electrodes, and their catalytic activity towards methanol oxidation was examined by cyclic voltammetry. The measurements indicated that the catalytic activity was superior to conventional bare Pd nanoparticles. As confirmed by electron microscopy imaging and supported by density-functional theory (DFT) calculations, we attribute the improved catalytic performance primarily to inhibition of Pd core sintering during the catalytic process by the metal-oxide shell

  15. Equipment Design and Cost Estimation for Small Modular Biomass Systems, Synthesis Gas Cleanup, and Oxygen Separation Equipment; Task 9: Mixed Alcohols From Syngas -- State of Technology

    SciTech Connect

    Nexant Inc.

    2006-05-01

    This deliverable is for Task 9, Mixed Alcohols from Syngas: State of Technology, as part of National Renewable Energy Laboratory (NREL) Award ACO-5-44027, ''Equipment Design and Cost Estimation for Small Modular Biomass Systems, Synthesis Gas Cleanup and Oxygen Separation Equipment''. Task 9 supplements the work previously done by NREL in the mixed alcohols section of the 2003 technical report Preliminary Screening--Technical and Economic Assessment of Synthesis Gas to Fuels and Chemicals with Emphasis on the Potential for Biomass-Derived Syngas.

  16. Tailor Made Synthesis of T-Shaped and π-STACKED Dimers in the Gas Phase: Concept for Efficient Drug Design and Material Synthesis

    NASA Astrophysics Data System (ADS)

    Kumar, Sumit; Das, Aloke

    2013-06-01

    Non-covalent interactions play a key role in governing the specific functional structures of biomolecules as well as materials. Thus molecular level understanding of these intermolecular interactions can help in efficient drug design and material synthesis. It has been found from X-ray crystallography that pure hydrocarbon solids (i.e. benzene, hexaflurobenzene) have mostly slanted T-shaped (herringbone) packing arrangement whereas mixed solid hydrocarbon crystals (i.e. solid formed from mixtures of benzene and hexafluorobenzene) exhibit preferentially parallel displaced (PD) π-stacked arrangement. Gas phase spectroscopy of the dimeric complexes of the building blocks of solid pure benzene and mixed benzene-hexafluorobenzene adducts exhibit similar structural motifs observed in the corresponding crystal strcutures. In this talk, I will discuss about the jet-cooled dimeric complexes of indole with hexafluorobenzene and p-xylene in the gas phase using Resonant two photon ionzation and IR-UV double resonance spectroscopy combined with quantum chemistry calculations. In stead of studying benzene...p-xylene and benzene...hexafluorobenzene dimers, we have studied corresponding indole complexes because N-H group is much more sensitive IR probe compared to C-H group. We have observed that indole...hexafluorobenzene dimer has parallel displaced (PD) π-stacked structure whereas indole...p-xylene has slanted T-shaped structure. We have shown here selective switching of dimeric structure from T-shaped to π-stacked by changing the substituent from electron donating (-CH3) to electron withdrawing group (fluorine) in one of the complexing partners. Thus, our results demonstrate that efficient engineering of the non-covalent interactions can lead to efficient drug design and material synthesis.

  17. Effects of aluminum additions to gas atomized reaction synthesis produced oxide dispersion strengthened alloys

    NASA Astrophysics Data System (ADS)

    Spicher, Alexander Lee

    The production of an aluminum containing ferritic oxide dispersion strengthened (ODS) alloy was investigated. The production method used in this study was gas atomization reaction synthesis (GARS). GARS was chosen over the previously commercial method of mechanical alloying (MA) process due to complications from this process. The alloy compositions was determined from three main components; corrosion resistance, dispersoid formation, and additional elements. A combination of Cr and Al were necessary in order to create a protective oxide in the steam atmosphere that the boiler tubing in the next generation of coal-fired power plants would be exposed to. Hf and Y were chosen as dispersoid forming elements due to their increased thermal stability and potential to avoid decreased strength caused by additions of Al to traditional ODS materials. W was used as an additive due to benefits as a strengthener as well as its benefits for creep rupture time. The final composition chosen for the alloy was Fe-16Cr-12Al-0.9W-0.25Hf-0.2Y at%. The aforementioned alloy, GA-1-198, was created through gas atomization with atomization gas of Ar-300ppm O2. The actual composition created was found to be Fe-15Cr-12.3Al-0.9W-0.24Hf-0.19Y at%. An additional alloy that was nominally the same without the inclusion of aluminum was created as a comparison for the effects on mechanical and corrosion properties. The actual composition of the comparison alloy, GA-1-204, was Fe-16Cr-0Al-0.9W-0.25Hf-0.24Y at%. An investigation on the processing parameters for these alloys was conducted on the GA-1-198 alloy. In order to predict the necessary amount of time for heat treatment, a diffusion study was used to find the diffusion rate of oxygen in cast alloys with similar composition. The diffusion rate was found to be similar to that of other GARS compositions that have been created without the inclusion of aluminum. The effect of heat treatment time was investigated with temperatures of 950°C, 1000

  18. Non-equilibrium processes by a gas phase synthesis of diamond

    NASA Astrophysics Data System (ADS)

    Rebrov, A. K.; Yudin, I. B.

    2016-11-01

    The analysis of influence of heterogeneous reactions in rarefied gas flows with dissociation and recombination is carried on for the first time, at least for hydrogen and methane flows. The flow in channels with heterogeneous reaction can be equilibrium and non-equilibrium, depending on a flow rate. Non-equilibrium effects are pronounced as a rule in the space between channel exit and substrate, where the activated gas flow to the surface of diamond deposition is formed. The gas dynamic analysis of gas jet deposition of diamond facilitates the optimization of experiments and their analysis.

  19. High pressure synthesis gas fermentation. [Quarterly status] report, July 15, 1991--October 14, 1991

    SciTech Connect

    Not Available

    1991-12-31

    Construction of the high pressure gas phase fermentation system is nearing completion. All non-explosion proof components will be housed separately in a gas-monitored plexiglas cabinet. A gas-monitoring system has been designed to ensure the safety of the operations in case of small or large accidental gas releases. Preliminary experiments investigating the effects of high pressure on Clostridium 1jungdahlii have shown that growth and CO uptake are not negatively affected and CO uptake by an increased total pressure of 100 psig at a syngas partial pressure of 10 psig.

  20. Synthesis of dimethyl ether and alternative fuels in the liquid phase from coal-derived synthesis gas

    SciTech Connect

    Bhatt, B.L.

    1992-09-01

    As part of the DOE-sponsored contract for the Synthesis of Dimethyl Ether (DME) and Alternative Fuels in the Liquid Phase from Coal- Derived Syngas, the single-step, slurry phase DME synthesis process was developed. The development involved screening of catalyst systems, process variable studies, and catalyst life studies in two 300 ml stirred autoclaves. As a spin-off of the Liquid Phase Methanol (LPMEOH*) process, the new process significantly improves the syngas conversion efficiency of the LPMEOH process. This improvement can be achieved by replacing a portion of methanol catalyst with a dehydration catalyst in the reactor, resulting in the product methanol being converted to DME, thus avoiding the thermodynamic equilibrium constraint of the methanol reaction. Overall, this increases syngas conversion per-pass. The selectivity and productivity of DME and methanol are affected by the catalyst system employed as well as operating conditions. A preferred catalyst system, consisting of a physical mixture of a methanol catalyst and a gamma alumina, was identified. An improvement of about 50% in methanol equivalent productivity was achieved compared to the LPMEOH process. Results from the process variable study indicate that higher pressure and CO[sub 2] removal benefit the process significantly. Limited life studies performed on the preferred catalyst system suggest somewhat higher than expected deactivation rate for the methanol catalyst. Several DME/methanol mixtures were measured for their key properties as transportation fuels. With small amounts of DME added, significant improvements in both flash points and Reid Vapor Pressure (RVP) were observed over the corresponding values of methanol alone.

  1. The economical production of alcohol fuels from coal-derived synthesis gas: Case studies, design, and economics

    SciTech Connect

    1995-10-01

    This project is a combination of process simulation and catalyst development aimed at identifying the most economical method for converting coal to syngas to linear higher alcohols to be used as oxygenated fuel additives. There are two tasks. The goal of Task 1 is to discover, study, and evaluate novel heterogeneous catalytic systems for the production of oxygenated fuel enhancers from synthesis gas, and to explore, analytically and on the bench scale, novel reactor and process concepts for use in converting syngas to liquid fuel products. The goal of Task 2 is to simulate, by computer, energy efficient and economically efficient processes for converting coal to energy (fuel alcohols and/or power). The primary focus is to convert syngas to fuel alcohols. This report contains results from Task 2. The first step for Task 2 was to develop computer simulations of alternative coal to syngas to linear higher alcohol processes, to evaluate and compare the economics and energy efficiency of these alternative processes, and to make a preliminary determination as to the most attractive process configuration. A benefit of this approach is that simulations will be debugged and available for use when Task 1 results are available. Seven cases were developed using different gasifier technologies, different methods for altering the H{sub 2}/CO ratio of the syngas to the desired 1.1/1, and with the higher alcohol fuel additives as primary products and as by-products of a power generation facility. Texaco, Shell, and Lurgi gasifier designs were used to test gasifying coal. Steam reforming of natural gas, sour gas shift conversion, or pressure swing adsorption were used to alter the H{sub 2}/CO ratio of the syngas. In addition, a case using only natural gas was prepared to compare coal and natural gas as a source of syngas.

  2. Synthesis of Fe Doped ZnO Nanowire Arrays that Detect Formaldehyde Gas.

    PubMed

    Jeon, Yoo Sang; Seo, Hyo Won; Kim, Su Hyo; Kim, Young Keun

    2016-05-01

    Owing to their chemical and thermal stability and doping effects on providing electrons to the conduction band, doped ZnO nanowires have generated interest for use in electronic devices. Here we report hydrothermally grown Fe-doped ZnO nanowires and their gas-sensing properties. The synthesized nanowires have a high crystallinity and are 60 nm in diameter and 1.7 μm in length. Field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) are employed to understand the doping effects on the microstructures and gas sensing properties. When the Fe-doped ZnO nanowire arrays were evaluated for gas sensing, responses were recorded through changes in temperature and gas concentration. Gas sensors consisting of ZnO nanowires doped with 3-5 at.% Fe showed optimum formaldehyde (HCHO) sensing performance at each working temperature.

  3. The synthesis of methanol and the reverse water-gas shift reaction over Zn-deposited Cu(100) and Cu(110) surfaces: comparison with Zn/Cu(111)

    NASA Astrophysics Data System (ADS)

    Nakamura, I.; Fujitani, T.; Uchijima, T.; Nakamura, J.

    1998-03-01

    The catalytic activity of Zn vapor-deposited Cu(100) and Cu(110) surfaces for methanol synthesis by the hydrogenation of CO 2 and the reverse water-gas shift reaction were studied using an XPS apparatus combined with a high-pressure flow reactor (18 atm). At a reaction temperature of 523 K, no promotional effect of Zn was observed for the methanol synthesis on both Zn/Cu(100) and Zn/Cu(110). The results were quite different from those for Zn/Cu(111), on which a significant promotion of methanol synthesis activity appeared to be due to the deposition of Zn, indicating that the promotional effect of Zn was sensitive to the surface structure of Cu. However, hysteresis was observed in the catalytic activity for methanol synthesis over the Zn/Cu(110) surface upon heating above 543 K in the reaction mixture. The activity became twice that measured before heating, which was close to the methanol synthesis activity of Zn/Cu(111) at the same Zn coverage. On the other hand, no such hysteresis was observed for the reverse water-gas shift reaction on Zn/Cu(110), indicating that the active site for methanol synthesis was not identical to that for the reverse water-gas shift reaction. In the post-reaction surface analysis, formate species was detected on both Zn/Cu(100) and Zn/Cu(110), whose coverage increased with increasing Zn coverage at 0< ΘZn<0.2. No correlation between the formate coverage and the methanol synthesis activity was obtained, which was in contrast to the results for Zn/Cu(111). Thus, the structure sensitivity observed in the catalytic activity of methanol synthesis over Zn-deposited Cu surfaces is ascribed to the significant difference in the reactivity of the formate intermediate.

  4. Effect of Varying Inert Gas and Acetylene Concentration on the Synthesis of Carbon Nanotubes.

    PubMed

    Afrin, Rahat; Abbas, Syed Mustansar; Shah, Nazar Abbas; Mustafa, Muhammad Farooq; Ali, Zulfiqar; Ahmad, Nisar

    2016-03-01

    The multiwalled carbon nanotubes (MWCNTs) with small diameter and high purity were achieved by chemical vapor deposition technique using silicon substrate. The introduction of specific concentration of inert gas with hydrocarbon played a key role in controlling morphology and diameter of MWCNTs. Nickel mixed ferrite nanoparticles were used as a catalyst for the growth of MWCNTs. Growth parameters like concentration of hydrocarbon source and inert gas flow, composition of catalyst particles and growth temperature were studied. In this work smaller diameter and twisted MWCNTs were formed by dilution of acetylene with argon gas. Electrical properties suggest a semimetallic behavior of synthesized MWCNTs.

  5. High pressure synthesis gas fermentation. [Quarterly status] report, October 15, 1991--January 14, 1992

    SciTech Connect

    Not Available

    1992-09-01

    The construction of the high pressure gas phase fermentation system has been completed. Photographs of the various components of the system are presented, along with an operating procedure for the equipment.

  6. Bench-scale demonstration of biological production of ethanol from coal synthesis gas. Quarterly report, January 1, 1993--March 31, 1993

    SciTech Connect

    Not Available

    1993-11-01

    Several batch experiments have been performed in developing the ethanol-producing isolates ER12 and ER18 for ethanol production from synthesis gas. In addition, Clostridium ljungdahlii, strain PETC, has been used in a two-stage continuous stirred tank reactor system. Ethanol concentrations from the CSTR system have reached 12 g/L.

  7. TiO2 Nanotubes: Recent Advances in Synthesis and Gas Sensing Properties

    PubMed Central

    Galstyan, Vardan; Comini, Elisabetta; Faglia, Guido; Sberveglieri, Giorgio

    2013-01-01

    Synthesis—particularly by electrochemical anodization-, growth mechanism and chemical sensing properties of pure, doped and mixed titania tubular arrays are reviewed. The first part deals on how anodization parameters affect the size, shape and morphology of titania nanotubes. In the second part fabrication of sensing devices based on titania nanotubes is presented, together with their most notable gas sensing performances. Doping largely improves conductivity and enhances gas sensing performances of TiO2 nanotubes. PMID:24184919

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

    SciTech Connect

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

    1995-12-31

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

  9. Direct carbide synthesis by multipulse excimer laser treatment of Ti samples in ambient CH4 gas at superatmospheric pressure

    NASA Astrophysics Data System (ADS)

    Mihailescu, I. N.; Chitica, N.; Teodorescu, V. S.; Popescu, M.; De Giorgi, M. L.; Luches, A.; Perrone, A.; Boulmer-Leborgne, Ch.; Hermann, J.; Dubreuil, B.; Udrea, S.; Barborica, A.; Iova, I.

    1994-05-01

    Successful carbidation of Ti in a layer forming on the surface of a Ti sample submitted to multipulse excimer (λ=308 nm) laser treatment in CH4 at a slightly superatmospheric pressure is reported. The layer is only surface contaminated with oxygen while its main part consists of fcc TiC. The layer apparently ends with a tail of carbides with low C content, extending deeper into the sample's bulk. The characteristics of the synthesized layer are suggested to be related to the peculiarities of the chemical synthesis which are enhanced by gas propulsion into a melted layer under the recoil action of a plasma evolving in front of the sample. A cavitation mechanism inside the melted surface layer in order to account for plasma initiation is proposed. This mechanism also facilitates the strong substance propulsion into the sample's bulk.

  10. Catalytic partial oxidation of methane to synthesis gas over a ruthenium catalyst: the role of the oxidation state.

    PubMed

    Rabe, Stefan; Nachtegaal, Maarten; Vogel, Frédéric

    2007-03-28

    The catalytic partial oxidation of methane to synthesis gas over ruthenium catalysts was investigated by thermogravimetry coupled with infrared spectroscopy (TGA-FTIR) and in situ X-ray absorption spectroscopy (XAS). It was found that the oxidation state of the catalyst influences the product formation. On oxidized ruthenium sites, carbon dioxide was formed. The reduced catalyst yielded carbon monoxide as a product. The influence of the temperature was also investigated. At temperatures below the ignition point of the reaction, the catalyst was in an oxidized state. At temperatures above the ignition point, the catalyst was reduced. This was also confirmed by the in situ XAS spectroscopy. The results indicate that both a direct reaction mechanism as well as a combustion-reforming mechanism can occur. The importance of knowing the oxidation state of the surface is discussed and a method to determine it under reaction conditions is presented.

  11. Low cost hydrogen/novel membrane technology for hydrogen separation from synthesis gas, Phase 1. [Polyetherimide, cellulose acetate and ethylcellulose

    SciTech Connect

    Not Available

    1986-01-01

    The goal of this program is to develop polymer membranes useful in the preparation of hydrogen from coal-derived synthesis gas. During this quarter the first experiment were aimed at developing high performance composite membranes for the separation of hydrogen from nitrogen and carbon monoxide. Three polymers have been selected as materials for these membranes: polyetherimide cellulose acetate and ethylcellulose. This quarter the investigators worked on polyetherimide and cellulose acetate membranes. The overall structure of these membranes is shown schematically in Figure 1. As shown, a microporous support membrane is first coated with a high flux intermediate layer then with an ultrathin permselective layer and finally, if necessary, a thin protective high flux layer. 1 fig., 4 tabs.

  12. Equipment Design and Cost Estimation for Small Modular Biomass Systems, Synthesis Gas Cleanup, and Oxygen Separation Equipment; Task 2.3: Sulfur Primer

    SciTech Connect

    Nexant Inc.

    2006-05-01

    This deliverable is Subtask 2.3 of Task 2, Gas Cleanup Design and Cost Estimates, of NREL Award ACO-5-44027, ''Equipment Design and Cost Estimation for Small Modular Biomass Systems, Synthesis Gas Cleanup and Oxygen Separation Equipment''. Subtask 2.3 builds upon the sulfur removal information first presented in Subtask 2.1, Gas Cleanup Technologies for Biomass Gasification by adding additional information on the commercial applications, manufacturers, environmental footprint, and technical specifications for sulfur removal technologies. The data was obtained from Nexant's experience, input from GTI and other vendors, past and current facility data, and existing literature.

  13. Optimization of a corn steep medium for production of ethanol from synthesis gas fermentation by Clostridium ragsdalei.

    PubMed

    Saxena, Jyotisna; Tanner, Ralph S

    2012-04-01

    Fermentation of biomass derived synthesis gas to ethanol is a sustainable approach that can provide more usable energy and environmental benefits than food-based biofuels. The effects of various medium components on ethanol production by Clostridium ragsdalei utilizing syngas components (CO:CO(2)) were investigated, and corn steep liquor (CSL) was used as an inexpensive nutrient source for ethanol production by C. ragsdalei. Elimination of Mg(2+), NH(4) (+) and PO(4) (3-) decreased ethanol production from 38 to 3.7, 23 and 5.93 mM, respectively. Eliminating Na(+), Ca(2+), and K(+) or increasing Ca(2+), Mg(2+), K(+), NH(4) (+) and PO(4) (3-) concentrations had no effect on ethanol production. However, increased Na(+) concentration (171 mM) inhibited growth and ethanol production. Yeast extract (0.5 g l(-1)) and trace metals were necessary for growth of C. ragsdalei. CSL alone did not support growth and ethanol production. Nutrients limiting in CSL were trace metals, NH(4) (+) and reducing agent (Cys: cysteine sulfide). Supplementation of trace metals, NH(4) (+) and CyS to CSL (20 g l(-1), wet weight basis) yielded better growth and similar ethanol production as compared to control medium. Using 10 g l(-1), the nutritional limitation led to reduced ethanol production. Higher concentrations of CSL (50 and 100 g l(-1)) were inhibitory for cell growth and ethanol production. The CSL could replace yeast extract, vitamins and minerals (excluding NH(4) (+)). The optimized CSL medium produced 120 and 50 mM of ethanol and acetate, respectively. The CSL could provide as an inexpensive source of most of the nutrients required for the syngas fermentation, and thus could improve the economics of ethanol production from biomass derived synthesis gas by C. ragsdalei.

  14. Controllable Synthesis of Formaldehyde Modified Manganese Oxide Based on Gas-Liquid Interfacial Reaction and Its Application of Electrochemical Sensing.

    PubMed

    Bai, Wushuang; Sheng, Qinglin; Nie, Fei; Zheng, Jianbin

    2015-12-30

    Controllable synthesis of manganese oxides was performed via a simple one-step synthetic method. Then obtained manganese oxides which exhibit flower-like, cloud-like, hexagon-like, and rod-like morphologies were modified by formaldehyde based on a simple self-made gas-liquid reaction device respectively and the modified manganese oxides with coral-like, scallop-like and rod-like morphology were synthesized accordingly. The obtained materials were characterized and the formation mechanism was also researched. Then the modified manganese oxides were used to fabricate electrochemical sensors to detect H2O2. Comparison of electrochemical properties between three kinds of modified manganese oxides was investigated and the best one has been successfully employed as H2O2 sensor which shows a low detection limit of 0.01 μM, high sensitivity of 162.69 μA mM(-1) cm(-2), and wide linear range of 0.05 μM-12.78 mM. The study provides a new method for controllable synthesis of metal oxides, and electrochemical application of formaldehyde modified manganese oxides will provides a new strategy for electrochemical sensing with high performance, low cost, and simple fabrication.

  15. Synthesis and characterization of nano crystalline nickel zinc ferrite for chlorine gas sensor at room temperature

    SciTech Connect

    Pawar, C. S.; Gujar, M. P.; Mathe, V. L.

    2015-06-24

    Nano crystalline Nickel Zinc ferrite (Ni{sub 0.25}Zn{sub 0.75}Fe{sub 2}O{sub 4}) thin films were synthesized by Sol Gel method for gas response. The phase and microstructure of the obtained Ni{sub 0.25}Zn{sub 0.75}Fe{sub 2}O{sub 4} thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). The nanostructured Ni{sub 0.25}Zn{sub 0.75}Fe{sub 2}O{sub 4} thin film shows single spinel phase. Magnetic study was obtained with the help of VSM. The effects of working temperature on the gas response were studied. The results reveal that the Ni{sub 0.25}Zn{sub 0.75}Fe{sub 2}O{sub 4} thin film gas sensor shows good selectivity to chlorine gas at room temperature. The sensor shows highest sensitivity (∼50%) at room temperature, indicating its application in detecting chlorine gas at room temperature in the future.

  16. Economics of Undiscovered Oil and Gas in the North Slope of Alaska: Economic Update and Synthesis

    USGS Publications Warehouse

    Attanasi, E.D.; Freeman, P.A.

    2009-01-01

    The U.S. Geological Survey (USGS) has published assessments by geologists of undiscovered conventional oil and gas accumulations in the North Slope of Alaska; these assessments contain a set of scientifically based estimates of undiscovered, technically recoverable quantities of oil and gas in discrete oil and gas accumulations that can be produced with conventional recovery technology. The assessments do not incorporate economic factors such as recovery costs and product prices. The assessors considered undiscovered conventional oil and gas resources in four areas of the North Slope: (1) the central North Slope, (2) the National Petroleum Reserve in Alaska (NPRA), (3) the 1002 Area of the Arctic National Wildlife Refuge (ANWR), and (4) the area west of the NPRA, called in this report the 'western North Slope'. These analyses were prepared at different times with various minimum assessed oil and gas accumulation sizes and with slightly different assumptions. Results of these past studies were recently supplemented with information by the assessment geologists that allowed adjustments for uniform minimum assessed accumulation sizes and a consistent set of assumptions. The effort permitted the statistical aggregation of the assessments of the four areas composing the study area. This economic analysis is based on undiscovered assessed accumulation distributions represented by the four-area aggregation and incorporates updates of costs and technological and fiscal assumptions used in the initial economic analysis that accompanied the geologic assessment of each study area.

  17. Nanoparticle films made by gas phase synthesis: comparison of various techniques and sensor applications

    NASA Astrophysics Data System (ADS)

    Heszler, Peter; Reyes, L. F.; Hoel, Anders; Landstrom, Lars; Lantto, V.; Granqvist, Claes-Goran

    2003-07-01

    Nanoparticles can be generated by several different gas phase methods, such as gas deposition, laser-assisted chemical vapor deposition, and laser ablation. Some of the most important aspects - such as size-distribution, structure, and chemical composition of the generated nanoparticles (specifically W and WO3) - are presented and compared. WO3 nanoparticle films were deposited by an advanced gas deposition technique and were tested for sensor applications. Two different sensor devices were fabricated: Firstly, a thin Au-WO3 nanoparticle sandwich film was constructed, and conductance fluctuations of the Au film were measured as the sensor was exposed to alcohol vapor. Secondly, conductivity changes of a thick WO3 nanoparticle film were detected as it was exposed to test gases (H2S, NO2, and CO).

  18. Toward industrial scale synthesis of ultrapure singlet nanoparticles with controllable sizes in a continuous gas-phase process

    NASA Astrophysics Data System (ADS)

    Feng, Jicheng; Biskos, George; Schmidt-Ott, Andreas

    2015-10-01

    Continuous gas-phase synthesis of nanoparticles is associated with rapid agglomeration, which can be a limiting factor for numerous applications. In this report, we challenge this paradigm by providing experimental evidence to support that gas-phase methods can be used to produce ultrapure non-agglomerated “singlet” nanoparticles having tunable sizes at room temperature. By controlling the temperature in the particle growth zone to guarantee complete coalescence of colliding entities, the size of singlets in principle can be regulated from that of single atoms to any desired value. We assess our results in the context of a simple analytical model to explore the dependence of singlet size on the operating conditions. Agreement of the model with experimental measurements shows that these methods can be effectively used for producing singlets that can be processed further by many alternative approaches. Combined with the capabilities of up-scaling and unlimited mixing that spark ablation enables, this study provides an easy-to-use concept for producing the key building blocks for low-cost industrial-scale nanofabrication of advanced materials.

  19. Toward industrial scale synthesis of ultrapure singlet nanoparticles with controllable sizes in a continuous gas-phase process

    PubMed Central

    Feng, Jicheng; Biskos, George; Schmidt-Ott, Andreas

    2015-01-01

    Continuous gas-phase synthesis of nanoparticles is associated with rapid agglomeration, which can be a limiting factor for numerous applications. In this report, we challenge this paradigm by providing experimental evidence to support that gas-phase methods can be used to produce ultrapure non-agglomerated “singlet” nanoparticles having tunable sizes at room temperature. By controlling the temperature in the particle growth zone to guarantee complete coalescence of colliding entities, the size of singlets in principle can be regulated from that of single atoms to any desired value. We assess our results in the context of a simple analytical model to explore the dependence of singlet size on the operating conditions. Agreement of the model with experimental measurements shows that these methods can be effectively used for producing singlets that can be processed further by many alternative approaches. Combined with the capabilities of up-scaling and unlimited mixing that spark ablation enables, this study provides an easy-to-use concept for producing the key building blocks for low-cost industrial-scale nanofabrication of advanced materials. PMID:26511290

  20. Novel nano coordination polymer based synthesis of porous ZnO hexagonal nanodisk for higher gas sorption and photocatalytic activities

    NASA Astrophysics Data System (ADS)

    Rakibuddin, M.; Ananthakrishnan, Rajakumar

    2016-01-01

    Zinc(II)-based nano co-ordination polymers (NCPs) are first prepared at room temperature from three different isomers of dihydroxysalophen (DHS) ligand with Zn(OAc)2·2H2O and 1,4-benzenedicarboxylic acid (BDC) in DMF solvent. Facile calcinations of [Zn (DHS) (BDC)]·nH2O (shortly denoted as Zn(II)-based NCP) at ambient conditions produces porous ZnO hexagonal nanodisks. Moreover, a novel approach has been introduced to observe the effect of ligand of the NCP on the physico-chemical properties of the as-synthesized ZnO. The porous ZnO nanodisks are characterized by FT-IR, PXRD, TEM, FESEM, EDX and BET analysis, and the results exhibit that they possess different sizes, surface areas and porosities. Nitrogen gas sorption capacity and photocatalytic activities of the as-prepared ZnO nanodisks are also checked, and it is noticed that they differ in these physico-chemical properties due to having different porosities and surface areas. A comparative study is also done with commercially available ZnO; interestingly, the commercial ZnO exhibited lower surface area, gas sorption and photocatalytic activity compared to the ZnO nanodisks. Hence, preparation of the ZnO through the NCP route and tuning their physico-chemical properties would offer new directions in synthesis of various nano metal oxides of unique properties.

  1. Catalyst-Free Synthesis of ZnO Nanowires on Oxidized Silicon Substrate for Gas Sensing Applications.

    PubMed

    Behera, B; Chandra, S

    2015-06-01

    In the present work, we report the synthesis of nanostructured ZnO by oxidation of zinc film without using a seed or catalyst layer. The zinc films were deposited on oxidized Si substrates by RF magnetron sputtering process. These were oxidized in dry and wet air/oxygen ambient. The optimized process yielded long nanowires of ZnO having diameter of around 60-70 nm and spread uniformly over the surface. The effect of oxidation temperature, time, Zn film thickness and the ambient has strong influence on the morphology of resulting nanostruxctured ZnO film. The films were characterized by scanning electron microscopy for morphological studies and X-ray diffraction (XRD) analysis to study the phase of the nanostructured ZnO. Room temperature photoluminescence (PL) measurements of the nanowires show UV and green emission. A sensor was designed and fabricated using nanostructured ZnO film, incorporating inter-digital-electrode (IDE) for the measurement of resistance of the sensing layer. The gas sensing properties were investigated from the measurement of change in resistance when exposed to vapours of different volatile organic compound (VOC) such as acetone, ethanol, methanol and 2-propanol. The results suggest that ZnO nanowires fabricated by this method have potential application in gas sensors.

  2. On-line gas chromatographic analysis of Fischer-Tropsch synthesis products formed in a supercritical reaction medium

    SciTech Connect

    Snavely, K.; Subramaniam, B.

    1997-10-01

    C{sub 1}-C{sub 30} products from Fischer-Tropsch synthesis, conducted in a supercritical n-hexane medium over an Fe catalyst in a fixed-bed reactor, are analyzed using on-line gas chromatography. A Hewlett-Packard 5890 Series II gas chromatograph (GC) is modified to minimize the effects of condensation of the on-line sample in the transfer lines. The GC is configured with a Supelco Petrocol DH capillary column connected to a flame ionization detector (FID) and two 1.83 m {times} 3.18 mm stainless steel columns placed in series, packed with 80/100 mesh HayeSep D, connected to a thermal conductivity detector (TCD). It is shown that pressure and temperature affect the elution order of oxygenates relative to hydrocarbons in the nonpolar capillary column. This phenomenon is exploited for obtaining improved resolution; several distinct methods produce similar elution orders. Ar, added to the syngas feed, is used to calculate syngas conversion. All compounds eluting before hexane (C{sub 1}-C{sub 5}, other than 2-methylpropene/1-butene and propanal/propanone) and nearly all the major peaks eluting after hexane are resolved in the capillary column. H{sub 2}, Ar, CO, CH{sub 4}, CO{sub 2}, and H{sub 2}O are resolved in the packed columns. The method provides excellent quantitative measurement of component mole fractions that are within the range of calibration.

  3. Bioconversion of coal derived synthesis gas to liquid fuels. Quarterly technical progress report, 1 April--30 June 1994

    SciTech Connect

    Jain, M.K.; Worden, R.M.; Grethlein, A.

    1994-07-18

    The overall objective of the project is to develop an integrated two-stage fermentation process for conversion of coal-derived synthesis gas to a mixture of alcohols. This is achieved in two steps. In the first step, Butyribacterium methylotrophicum converts carbon monoxide (CO) to butyric and acetic acids. Subsequent fermentation of the acids by Clostridium acetobutylicum leads to the production of butanol and ethanol. The tasks for this quarter were: development/isolation of superior strains for fermentation of syngas; evaluation of bioreactor configuration for improved mass transfer of syngas; recovery of carbon and electrons from H{sub 2}-CO{sub 2}; initiation of pervaporation for recovery of solvents; and selection of solid support material for trickle-bed fermentation. Technical progress included the following. Butyrate production was enhanced during H{sub 2}/CO{sub 2} (50/50) batch fermentation. Isolation of CO-utilizing anaerobic strains is in progress. Pressure (15 psig) fermentation was evaluated as a means of increasing CO availability. Polyurethane foam packing material was selected for trickle bed solid support. Cell recycle fermentation on syngas operated for 3 months. Acetate was the primary product at pH 6.8. Trickle bed and gas lift fermentor designs were modified after initial water testing. Pervaporation system was constructed. No alcohol selectivity was shown with the existing membranes during initial start-up.

  4. Synthesis, Characterization and Gas Sensing Properties of Ag@α-Fe2O3 Core–Shell Nanocomposites

    PubMed Central

    Mirzaei, Ali; Janghorban, Kamal; Hashemi, Babak; Bonavita, Anna; Bonyani, Maryam; Leonardi, Salvatore Gianluca; Neri, Giovanni

    2015-01-01

    Ag@α-Fe2O3 nanocomposite having a core–shell structure was synthesized by a two-step reduction-sol gel approach, including Ag nanoparticles synthesis by sodium borohydride as the reducing agent in a first step and the subsequent mixing with a Fe+3 sol for α-Fe2O3 coating. The synthesized Ag@α-Fe2O3 nanocomposite has been characterized by various techniques, such as SEM, TEM and UV-Vis spectroscopy. The electrical and gas sensing properties of the synthesized composite towards low concentrations of ethanol have been evaluated. The Ag@α-Fe2O3 nanocomposite showed better sensing characteristics than the pure α-Fe2O3. The peculiar hierarchical nano-architecture and the chemical and electronic sensitization effect of Ag nanoparticles in Ag@α-Fe2O3 sensors were postulated to play a key role in modulating gas-sensing properties in comparison to pristine α-Fe2O3 sensors. PMID:28347032

  5. Synthesis and characterization of WC-Co nanosized composite powders with in situ carbon and gas carbon sources

    NASA Astrophysics Data System (ADS)

    Yang, Qiumin; Yang, Jiangao; Yang, Hailin; Su, Wei; Ruan, Jianming

    2016-07-01

    This study presented nanosized WC-Co composite powders synthesized using a one-step reduction-carbonization process with a combination of CH4/H2 as a gas carbon source and soluble starch as an in situ carbon source. The results of carbon analysis and X-ray diffraction revealed that WC-Co nanocomposite powders with a pure WC and Co phase could be obtained at 1100 °C after 0.5 h. A higher gas flow ratio of CH4/H2 during the reduction-carbonization process led to a higher total carbon content of the sample. A field emission scanning electron microscope confirmed that the particles in the WC-6 wt% Co composite powders had the lowest average size of 43 nm with equiaxed shapes. A sintering neck was observed in the WC-3 wt% Co composite powders whereas faceted particles were found in the WC-12 wt% Co composite powders. Moreover, this method has advantages of simple processing, rapid synthesis and good applicability in potential industry application.

  6. Catalyst and process development for synthesis gas conversion to isobutylene. Quarterly report, January 1, 1993--March 31, 1993

    SciTech Connect

    Anthony, R.G.; Akgerman, A.

    1993-04-17

    The objectives of this project are to develop a new catalyst, the kinetics for this catalyst, reactor models for trickle bed, slurry and fixed bed reactors, and simulate the performance of fixed bed trickle flow reactors, slurry flow reactors, and fixed bed gas phase reactors for conversion of a hydrogen lean synthesis gas to isobutylene. The six main accomplishments for the quarter are the following: (1) activity testing with the 7% (wt) Ce-ZrO{sub 2}, (2) activity testing the same catalyst with CO from an aluminum cylinder, (3) preparation of ZrO{sub 2} by heating zirconyl nitrate, (4) preparation of an active zirconia prepared by a modified sol gel procedure and evaluation of the catalytic activity of a commercial zirconia and the catalysts prepared by the sol gel procedure, (5) determining the effect of separator temperatures and oil flow rate on the performance of a trickle bed reactor, and (6) calculation of the equilibrium composition of the C{sub 2} to C{sub 5} olefins, and initiation of the development of a macrokinetic model. The details of each of these accomplishments are discussed.

  7. Synthesis and Transport Properties of Novel MOF/PIM-1/MOF Sandwich Membranes for Gas Separation.

    PubMed

    Fuoco, Alessio; Khdhayyer, Muhanned R; Attfield, Martin P; Esposito, Elisa; Jansen, Johannes C; Budd, Peter M

    2017-02-11

    Metal-organic frameworks (MOFs) were supported on polymer membrane substrates for the fabrication of composite polymer membranes based on unmodified and modified polymer of intrinsic microporosity (PIM-1). Layers of two different MOFs, zeolitic imidazolate framework-8 (ZIF-8) and Copper benzene tricarboxylate ((HKUST-1), were grown onto neat PIM-1, amide surface-modified PIM-1 and hexamethylenediamine (HMDA) -modified PIM-1. The surface-grown crystalline MOFs were characterized by a combination of several techniques, including powder X-ray diffraction, infrared spectroscopy and scanning electron microscopy to investigate the film morphology on the neat and modified PIM-1 membranes. The pure gas permeabilities of He, H₂, O₂, N₂, CH₄, CO₂ were studied to understand the effect of the surface modification on the basic transport properties and evaluate the potential use of these membranes for industrially relevant gas separations. The pure gas transport was discussed in terms of permeability and selectivity, highlighting the effect of the MOF growth on the diffusion coefficients of the gas in the new composite polymer membranes. The results confirm that the growth of MOFs on polymer membranes can enhance the selectivity of the appropriately functionalized PIM-1, without a dramatic decrease of the permeability.

  8. Synthesis and Transport Properties of Novel MOF/PIM-1/MOF Sandwich Membranes for Gas Separation

    PubMed Central

    Fuoco, Alessio; Khdhayyer, Muhanned R.; Attfield, Martin P.; Esposito, Elisa; Jansen, Johannes C.; Budd, Peter M.

    2017-01-01

    Metal-organic frameworks (MOFs) were supported on polymer membrane substrates for the fabrication of composite polymer membranes based on unmodified and modified polymer of intrinsic microporosity (PIM-1). Layers of two different MOFs, zeolitic imidazolate framework-8 (ZIF-8) and Copper benzene tricarboxylate ((HKUST-1), were grown onto neat PIM-1, amide surface-modified PIM-1 and hexamethylenediamine (HMDA) -modified PIM-1. The surface-grown crystalline MOFs were characterized by a combination of several techniques, including powder X-ray diffraction, infrared spectroscopy and scanning electron microscopy to investigate the film morphology on the neat and modified PIM-1 membranes. The pure gas permeabilities of He, H2, O2, N2, CH4, CO2 were studied to understand the effect of the surface modification on the basic transport properties and evaluate the potential use of these membranes for industrially relevant gas separations. The pure gas transport was discussed in terms of permeability and selectivity, highlighting the effect of the MOF growth on the diffusion coefficients of the gas in the new composite polymer membranes. The results confirm that the growth of MOFs on polymer membranes can enhance the selectivity of the appropriately functionalized PIM-1, without a dramatic decrease of the permeability. PMID:28208658

  9. Microwave-assisted synthesis of SnO₂ nanorods for oxygen gas sensing at room temperature.

    PubMed

    Azam, Ameer; Habib, Sami S; Salah, Numan A; Ahmed, Faheem

    2013-01-01

    High-quality single-crystalline SnO₂ nanorods were synthesized using a microwave-assisted solution method. The nanorods were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), ultraviolet-visible and Raman spectroscopy, Brunauer-Emmett-Teller (BET), and electrical resistance measurements. The XRD pattern indicated the formation of single-phase SnO₂ nanorods with rutile structure. FE-SEM and TEM images revealed tetragonal nanorods of about 450-500 nm in length and 60-80 nm in diameter. The nanorods showed a higher BET surface area of 288 m²/g, much higher than that of previously reported work. The Raman scattering spectra indicated a typical rutile phase of the SnO₂. The absorption spectrum showed an absorption peak centered at 340 nm, and the band-gap value was found to be 3.64 eV. The gas-sensing properties of the SnO₂ nanorods for oxygen gas with different concentrations were measured at room temperature. It was found that the value of resistance increased with the increase in oxygen gas concentration in the test chamber. The SnO₂ nanorods exhibited high sensitivity and rapid response-recovery characteristics to oxygen gas, and could detect oxygen concentration as low as 1, 3, 5, and 10 ppm.

  10. Gas-Phase Synthesis of Singly and Multiply Charged Polyoxovanadate Anions Employing Electrospray Ionization and Collision Induced Dissociation

    NASA Astrophysics Data System (ADS)

    Al Hasan, Naila M.; Johnson, Grant E.; Laskin, Julia

    2013-09-01

    Electrospray ionization mass spectrometry (ESI-MS) combined with in-source fragmentation and tandem mass spectrometry (MS/MS) experiments were used to generate a wide range of singly and multiply charged vanadium oxide cluster anions including VxOy n- and VxOyCln- ions (x = 1-14, y = 2-36, n = 1-3), protonated clusters, and ligand-bound polyoxovanadate anions. The cluster anions were produced by electrospraying a solution of tetradecavanadate, V14O36Cl(L)5 (L = Et4N+, tetraethylammonium), in acetonitrile. Under mild source conditions, ESI-MS generates a distribution of doubly and triply charged VxOyCln- and VxOyCl(L)(n-1)- clusters predominantly containing 14 vanadium atoms as well as their protonated analogs. Accurate mass measurement using a high-resolution LTQ/Orbitrap mass spectrometer (m/Δm = 60,000 at m/z 410) enabled unambiguous assignment of the elemental composition of the majority of peaks in the ESI-MS spectrum. In addition, high-sensitivity mass spectrometry allowed the charge state of the cluster ions to be assigned based on the separation of the major from the much less abundant minor isotope of vanadium. In-source fragmentation resulted in facile formation of smaller VxOyCl(1-2)- and VxOy (1-2)- anions. Collision-induced dissociation (CID) experiments enabled systematic study of the gas-phase fragmentation pathways of the cluster anions originating from solution and from in-source CID. Surprisingly simple fragmentation patterns were obtained for all singly and doubly charged VxOyCl and VxOy species generated through multiple MS/MS experiments. In contrast, cluster anions originating directly from solution produced comparatively complex CID spectra. These results are consistent with the formation of more stable structures of VxOyCl and VxOy anions through low-energy CID. Furthermore, our results demonstrate that solution-phase synthesis of one precursor cluster anion combined with gas-phase CID is an efficient approach for the top-down synthesis of a

  11. Ultraviolet-gas phase and -photocatalytic synthesis from CO and NH3. [photolysis products

    NASA Technical Reports Server (NTRS)

    Hubbard, J. S.; Voecks, G. E.; Hobby, G. L.; Ferris, J. P.; Williams, E. A.; Nicodem, D. E.

    1975-01-01

    Ammonium cyanate is identified as the major product of the photolysis of gaseous NH3-CO mixtures at 206.2 or 184.9 nm. Lesser amounts of urea, biurea, biuret semicarbazide, formamide and cyanide are observed. A series of 18 reactions underlying the formation of photolysis products is presented and discussed. Photocatalytic syntheses of C-14-urea, -formamide, and -formaldehyde are carried out through irradiation of (C-14)O and NH3 in the presence of Vycor, silica gel, or volcanic ash shale surfaces. The possible contributions of the relevant reactions to the abiotic synthesis of organic nitrogen compounds on Mars, the primitive earth, and in interstellar space are examined.

  12. Synthesis, characterization, and gas-sensing properties of monodispersed SnO{sub 2} nanocubes

    SciTech Connect

    Runa, A; Bala, Hari E-mail: fuwy56@163.com; Wang, Yan; Chen, Jingkuo; Zhang, Bowen; Li, Huayang; Fu, Wuyou E-mail: fuwy56@163.com; Wang, Xiaodong; Sun, Guang; Cao, Jianliang; Zhang, Zhanying

    2014-08-04

    Monodispersed single-crystalline SnO{sub 2} nanocubes with exposed a large percentage of high-energy surfaces have been synthesized by a simple solvothermal process at low temperature without any templates and catalysts. The as-prepared samples have been characterized by X-ray diffraction and transmission electron microscopy. Many outstanding characters of the final products have been shown, such as uniform particle size, high purity, and monodispersity. In property, superior gas-sensing properties such as high response, rapid response-recovery time, and good selectivity have also been shown to ethanol at an optimal working temperature of as low as 280 °C. It indicates that the as-prepared SnO{sub 2} nanocubes are promising for gas sensors.

  13. Porous Polymer Networks: Synthesis, Porosity, and Applications in Gas Storage/Separation

    SciTech Connect

    Lu, Weigang; Yuan, Daqiang; Zhao, Dan; Schilling, Christine Inge; Plietzsch, Oliver; Muller, Thierry; Braese, Stefano; Guenther, Johannes; Blumel, Janet; Krishna, Rajamani; Li, Zhen; Zhou, Hong-Cai

    2010-11-09

    Three porous polymer networks (PPNs) have been synthesized by the homocoupling of tetrahedral monomers. Like other hyper-cross-linked polymer networks, these materials are insoluble in conventional solvents and exhibit high thermal and chemical stability. Their porosity was confirmed by N₂ sorption isotherms at 77 K. One of these materials, PPN-3, has a Langmuir surface area of 5323 m² g-1. Their clean energy applications, especially in H₂, CH₄, and CO₂ storage, as well as CO₂/CH₄ separation, have been carefully investigated. Although PPN-1 has the highest gas affinity because of its smaller pore size, the maximal gas uptake capacity is directly proportional to their surface area. PPN-3 has the highest H₂ uptake capacity among these three (4.28 wt %, 77 K). Although possessing the lowest surface area, PPN-1 shows the best CO₂/CH₄ selectivity among them.

  14. Hydrothermal synthesis of h-MoO3 microrods and their gas sensing properties to ethanol

    NASA Astrophysics Data System (ADS)

    Liu, Yueli; Yang, Shuang; Lu, Yu; Podval'naya, Natal'ya V.; Chen, Wen; Zakharova, Galina S.

    2015-12-01

    Hexagonal molybdenum trioxide (h-MoO3) microrods were successfully synthesized via a novel and facile hydrothermal route from peroxomolybdate solution with the presence of NH4Cl as the mineralizer. A variety of the techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry combined with the thermal gravimetric analysis (DSC-TG) were used to characterize the product. The gas sensing test indicates that h-MoO3 microrods have a good response to 5-500 ppm ethanol in the range of 273-380 °C, and the optimum operating temperature is 332 °C with a high sensitivity of 8.24 to 500 ppm ethanol. Moreover, it also has a good selectivity toward ethanol gas if compared with other gases, such as ammonia, methanol and toluene. The sensing mechanism of h-MoO3 microrods to ethanol was also discussed.

  15. Chemical synthesis of zinc oxide nanorods for enhanced hydrogen gas sensing

    NASA Astrophysics Data System (ADS)

    Musarrat, Jabeen; Muhammad Azhar, Iqbal; R Vasant, Kumar; Mansoor, Ahmed; Muhammad Tayyeb, Javed

    2014-01-01

    Zinc oxide (ZnO) nanorods are prepared using equimolar solution of zinc nitrate ((Zn(NO3)2) and hexamethylenetetramine (C6H12N4) by the hydrothermal technique at 80 °C for 12 h. Epitaxial growth is explored by X-ray diffraction (XRD) patterns, revealing that the ZnO nanorods have a hexagonal (wurtzite) structure. Absorption spectra of ZnO are measured by UV—visible spectrometer. The surface morphology is investigated by field emission scanning electron microscopy (FESEM). The synthesized ZnO nanorods are used for detecting the 150 °C hydrogen gas with a concentration over 1000 ppm. The obtained results show a reversible response. The influence of operating temperature on hydrogen gas detecting characteristic of ZnO nanorods is also investigated.

  16. Synthesis and Characterization of Thiazolium-Based Room Temperature Ionic Liquids for Gas Separations

    SciTech Connect

    Hillesheim, Patrick C; Mahurin, Shannon Mark; Fulvio, Pasquale F; Yeary, Joshua S; Oyola, Yatsandra; Jiang, Deen; Dai, Sheng

    2012-01-01

    A series of novel thiazolium-bis(triflamide) based ionic liquids has been synthesized and characterized. Physicochemical properties of the ionic liquids such as thermal stability, phase transitions, and infrared spectra were analysed and compared to the imidazolium-based congeners. Several unique classes of ancillary substitutions are examined with respect to impacts on overall structure, in addition to their carbon dioxide absorption properties in supported ionic-liquid membranes for gas separation.

  17. Synthesis of formamide and isocyanic acid after ion irradiation of frozen gas mixtures

    NASA Astrophysics Data System (ADS)

    Kaňuchová, Z.; Urso, R. G.; Baratta, G. A.; Brucato, J. R.; Palumbo, M. E.; Strazzulla, G.

    2016-01-01

    Context. Formamide (NH2HCO) and isocyanic acid (HNCO) have been observed as gaseous species in several astronomical environments such as cometary comae and pre- and proto-stellar objects. A debate is open on the formation route of those molecules, in particular if they are formed by chemical reactions in the gas phase and/or on grains. In this latter case it is relevant to understand if the formation occurs through surface reactions or is induced by energetic processing. Aims: We present arguments that support the formation of formamide in the solid phase by cosmic-ion-induced energetic processing of ices present as mantles of interstellar grains and on comets. Formamides, along with other molecules, are expelled in the gas phase when the physical parameters are appropriate to induce the desorption of ices. Methods: We have performed several laboratory experiments in which ice mixtures (H2O:CH4:N2, H2O:CH4:NH3, and CH3OH:N2) were bombarded with energetic (30-200 keV) ions (H+ or He+). FTIR spectroscopy was performed before, during, and after ion bombardment. In particular, the formation of HNCO and NH2HCO was measured quantiatively. Results: Energetic processing of ice can quantitatively reproduce the amount of NH2HCO observed in cometary comae and in many circumstellar regions. HNCO is also formed, but additional formation mechanisms are requested to quantitatively account for the astronomical observations. Conclusions: We suggest that energetic processing of ices in the pre- and proto-stellar regions and in comets is the main mechanism to produce formamide, which, once it is released in the gas phase because of desorption of ices, is observed in the gas phase in these astrophysical environments.

  18. Synthesis and Characterization of Thiazolium-Based Room Temperature Ionic Liquids for Gas Separations

    SciTech Connect

    Hillesheim, PC; Mahurin, SM; Fulvio, PF; Yeary, JS; Oyola, Y; Jiang, DE; Dai, S

    2012-09-05

    A series of novel thiazolium-bis(triflamide) based ionic liquids has been synthesized and characterized. Physicochemical properties of the ionic liquids such as thermal stability, phase transitions, and infrared spectra were analyzed and compared to the imidazolium-based congeners. Several unique classes of ancillary substitutions are examined with respect to impacts on overall structure, in addition to their carbon dioxide absorption properties in supported ionic-liquid membranes for gas separation.

  19. Gas-Phase Synthesis and Characterization of CH4-Loaded Hydroquinone Clathrates

    SciTech Connect

    Lee, J.; Lee, Y; Takeya, S; Kawamura, T; Yamamoto, Y; Lee, Y; Yoon, J

    2010-01-01

    A CH{sub 4}-loaded hydroquinone (HQ) clathrate was synthesized via a gas-phase reaction using the {alpha}-form of crystalline HQ and CH{sub 4} gas at 12 MPa and room temperature. Solid-state {sup 13}C cross-polarization/magic angle spinning (CP/MAS) NMR and Raman spectroscopic measurements confirm the incorporation of CH{sub 4} molecules into the cages of the HQ clathrate framework. The chemical analysis indicates that about 69% of the cages are filled by CH{sub 4} molecules, that is, 0.69 CH{sub 4} per three HQ molecules. Rietveld refinement using synchrotron X-ray powder diffraction (XRD) data shows that the CH{sub 4}-loaded HQ clathrate adopts the {beta}-form of HQ clathrate in a hexagonal space group R3 with lattice parameters of a = 16.6191 {angstrom} and c = 5.5038 {angstrom}. Time-resolved synchrotron XRD and quadrupole mass spectroscopic measurements show that the CH{sub 4}-loaded HQ clathrate is stable up to 368 K and gradually transforms to the {alpha}-form by releasing the confined CH{sub 4} gases between 368-378 K. Using solid-state {sup 13}C CP/MAS NMR, the reaction kinetics between the {alpha}-form HQ and CH{sub 4} gas is qualitatively described in terms of the particle size of the crystalline HQ.

  20. Gas-phase synthesis and characterization of CH4-loaded hydroquinone clathrates.

    PubMed

    Lee, Jong-Won; Lee, Yongjae; Takeya, Satoshi; Kawamura, Taro; Yamamoto, Yoshitaka; Lee, Yun-Je; Yoon, Ji-Ho

    2010-03-11

    A CH(4)-loaded hydroquinone (HQ) clathrate was synthesized via a gas-phase reaction using the alpha-form of crystalline HQ and CH(4) gas at 12 MPa and room temperature. Solid-state (13)C cross-polarization/magic angle spinning (CP/MAS) NMR and Raman spectroscopic measurements confirm the incorporation of CH(4) molecules into the cages of the HQ clathrate framework. The chemical analysis indicates that about 69% of the cages are filled by CH(4) molecules, that is, 0.69 CH(4) per three HQ molecules. Rietveld refinement using synchrotron X-ray powder diffraction (XRD) data shows that the CH(4)-loaded HQ clathrate adopts the beta-form of HQ clathrate in a hexagonal space group R3 with lattice parameters of a = 16.6191 A and c = 5.5038 A. Time-resolved synchrotron XRD and quadrupole mass spectroscopic measurements show that the CH(4)-loaded HQ clathrate is stable up to 368 K and gradually transforms to the alpha-form by releasing the confined CH(4) gases between 368-378 K. Using solid-state (13)C CP/MAS NMR, the reaction kinetics between the alpha-form HQ and CH(4) gas is qualitatively described in terms of the particle size of the crystalline HQ.

  1. A simple large-scale synthesis of mesoporous In2O3 for gas sensing applications

    NASA Astrophysics Data System (ADS)

    Zhang, Su; Song, Peng; Yan, Huihui; Yang, Zhongxi; Wang, Qi

    2016-08-01

    In this paper, large-scale mesoporous In2O3 nanostructures were synthesized by a facile Lewis acid catalytic the furfural alcohol resin (FAR) template route for the high-yield. Their morphology and structure were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential thermal and thermogravimetry analysis (DSC-TG) and the Brunauer-Emmett-Teller (BET) approach. The as-obtained mesoporous In2O3 nanostructures possess excellent mesoporous and network structure, which increases the contact area with the gases, it is conducive for adsorption-desorption of gas on the surface of In2O3. The In2O3 particles and pores were both about 15 nm and very uniform. In gas-sensing measurements with target gases, the gas sensor based on mesoporous In2O3 nanostructures showed a good response, short response-recovery time, good selectivity and stability to ethanol. These properties are due to the large specific surface area of mesoporous structure. This synthetic method could use as a new design concept for functional mesoporous nanomaterials and for mass production.

  2. Biological conversion of synthesis gas. [Chlorobium thiosulfatophilum, chlorobium phaeobacteroides, and Rhodospirillum rubrum

    SciTech Connect

    Not Available

    1992-01-06

    The anaerobic bacterium Rhodospirillum rubrum has been chosen for catalysis of the biological water gas shift reaction. Two bacteria, Chlorobium thiosulfatophilum and Chlorobium phaeobacteroides, are being evaluated as candidates for H{sub 2}S conversion to elemental sulfur. Since these latter two organisms both grow and convert H{sub 2}S in batch culture using standard basal medium, the choice of a suitable bacterium must be made in consideration of specific growth and uptake rates. Produced elemental sulfur stability against further oxidation to sulfate, and minimal use of H{sub 2} as a producing agent must also be considered. The effects of temperature on the performance of R. rubrum were evaluated. It was found that the cell concentration was highest at temperatures of 25 and 30{degree}C, and that the specific uptake rate was highest at temperatures of 30, 32 and 34{degree}C. No growth was observed at 37{degree}C. Also, temperature did not affect the yield of H{sub 2} from CO. Thus, R. rubrum may be used for biological rates gas shift at any temperature between 30 and 34{degree}C, although growth is maximized at lower temperatures. Preliminary studies with C. thiosulfatophilum showed rapid utilization of H{sub 2}S from the gas and liquid phases with subsequent production of elemental sulfur. Elemental sulfur production interfered with cell concentrations measurements, although a technique has been developed to rectify this problem.

  3. Synthesis gas production through biomass direct chemical looping conversion with natural hematite as an oxygen carrier.

    PubMed

    Huang, Zhen; He, Fang; Feng, Yipeng; Zhao, Kun; Zheng, Anqing; Chang, Sheng; Li, Haibin

    2013-07-01

    Biomass direct chemical looping (BDCL) conversion with natural hematite as an oxygen carrier was conducted in a fluidized bed reactor under argon atmosphere focusing on investigation the cyclic performance of oxygen carrier. The presence of oxygen carrier can evidently promote the biomass conversion. The gas yield and carbon conversion increased from 0.75 Nm(3)/kg and 62.23% of biomass pyrolysis to 1.06 Nm(3)/kg and 87.63% of BDCL, respectively. The components of the gas product in BDCL were close to those in biomass pyrolysis as the cyclic number increased. The gas yield and carbon conversion decreased from 1.06 Nm(3)/kg and 87.63% at 1st cycle to 0.93 Nm(3)/kg and 77.18% at 20th cycle, respectively, due to the attrition and structural changes of oxygen carrier. X-ray diffraction (XRD) analysis showed that the reduction extent of oxygen carrier increased with the cycles. Scanning electron microscope (SEM) and pore structural analysis displayed that agglomeration was observed with the cycles.

  4. Hydrothermal synthesis and NH3 gas sensing property of WO3 nanorods at low temperature

    NASA Astrophysics Data System (ADS)

    Dien Nguyen, Dac; Vuong Dang, Duc; Chien Nguyen, Duc

    2015-09-01

    One-dimensional self-assembled single-crystalline hexagonal tungsten trioxide (WO3) nanostructures were synthesized by wet chemical-assisted hydrothermal processing at 120 °C for 24 h using sodium tungstate and hydrochloric acid. Urchin-like hierarchical nanorods (petal size: ∼16 nm diameter and 110 nm length) were obtained. The samples were characterized by field emission scanning electron microscopy, transmission electron microscopy, energy dispersive x-ray spectroscopy and x-ray diffraction. Sensors based on WO3 nanorods were fabricated by coating them on SiO2/Si substrate attached with Pt interdigitated electrodes. NH3 gas-sensing properties of WO3 nanorods were measured at different temperatures ranging from 50 °C to 350 °C and the response was evaluated as a function of ammonia gas concentration. The gas-sensing results reveal that WO3 nanorods sensor exhibits high sensitivity and selectivity to NH3 at low operating temperature (50 °C). The maximum response reached at 50 °C was 192 for 250 ppm NH3, with response and recovery times of 10 min and 2 min, respectively.

  5. Synthesis of hierarchical SnO2 nanoflowers with enhanced acetic acid gas sensing properties

    NASA Astrophysics Data System (ADS)

    Jin, W. X.; Ma, S. Y.; Tie, Z. Z.; Li, W. Q.; Luo, J.; Cheng, L.; Xu, X. L.; Wang, T. T.; Jiang, X. H.; Mao, Y. Z.

    2015-10-01

    Different morphologies hierarchical flower-like tin dioxide (SnO2) nanostructures were fabricated by changing the volume ratio of glycol and de-ionized water (Vg:Vw = 0, 1:2, 1:1 and 2:1) under a template-free and low-cost hydrothermal method and subsequent calcinations. The architectures, morphologies and gas sensing performances of the products were characterized by X-ray diffraction patterns (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) and gas-sensing measurement device. It can be observed that all the nanoflowers were composed of two-dimensional (2D) nanosheets, and the thickness of nanosheets is only about 9 nm when Vg:Vw = 1:1. The sensor based on the product of Vg:Vw = 1:1 exhibited excellent gas sensing performance toward 500 ppm acetic acid at 260 °C, and the response value of this sensor was about 153.6, which was above 7.5 times higher than that of ammonia (about 20.3). In addition, the 3D flower-like SnO2 nanostructures exhibited not only high response and selectivity to ppm level acetone, but also fast response and recovery time within 10 s, demonstrating it can be used as a potential candidate for detecting acetic acid. Finally, the possible formation mechanism was proposed, too.

  6. Synthesis of alpha-chymotrypsin/polymer composites by a reverse micelle/gas antisolvent method.

    PubMed

    Li, Wei; Zhang, Jianling; Zhang, Chaoxing; Feng, Xiaoying; Han, Buxing; Yang, Guanying

    2007-09-01

    Alpha-chymotrypsin (CT)/polyvinylpyrrolidone (PVP) composites was synthesized by combination of reverse micelles and CO(2). In this method, the two reverse micellar solutions containing CT and PVP, respectively, were first mixed, then compressed CO(2) was used as an antisolvent to precipitate the CT and PVP simultaneously and CT/PVP composites were successfully prepared. The morphology of the obtained CT/PVP composites was characterized by transmission electron microscopy (TEM). The FTIR spectra of the composites showed that there was interaction between CT and PVP. The storage activity of the enzyme immobilized on the polymer by this method was higher than that of the pure enzyme. This method has some advantages and can be easily applied to the synthesis of some other enzyme/polymer composites.

  7. Gas phase synthesis of non-bundled, small diameter single-walled carbon nanotubes with near-armchair chiralities

    SciTech Connect

    Mustonen, K.; Laiho, P.; Kaskela, A.; Zhu, Z.; Reynaud, O.; Houbenov, N.; Tian, Y.; Jiang, H.; Kauppinen, E. I.; Susi, T.; Nasibulin, A. G.

    2015-07-06

    We present a floating catalyst synthesis route for individual, i.e., non-bundled, small diameter single-walled carbon nanotubes (SWCNTs) with a narrow chiral angle distribution peaking at high chiralities near the armchair species. An ex situ spark discharge generator was used to form iron particles with geometric number mean diameters of 3–4 nm and fed into a laminar flow chemical vapour deposition reactor for the continuous synthesis of long and high-quality SWCNTs from ambient pressure carbon monoxide. The intensity ratio of G/D peaks in Raman spectra up to 48 and mean tube lengths up to 4 μm were observed. The chiral distributions, as directly determined by electron diffraction in the transmission electron microscope, clustered around the (n,m) indices (7,6), (8,6), (8,7), and (9,6), with up to 70% of tubes having chiral angles over 20°. The mean diameter of SWCNTs was reduced from 1.10 to 1.04 nm by decreasing the growth temperature from 880 to 750 °C, which simultaneously increased the fraction of semiconducting tubes from 67% to 80%. Limiting the nanotube gas phase number concentration to ∼10{sup 5 }cm{sup −3} prevented nanotube bundle formation that is due to collisions induced by Brownian diffusion. Up to 80% of 500 as-deposited tubes observed by atomic force and transmission electron microscopy were individual. Transparent conducting films deposited from these SWCNTs exhibited record low sheet resistances of 63 Ω/□ at 90% transparency for 550 nm light.

  8. Large-scale synthesis of the controlled-geometry carbon coils by the manipulation of the SF6 gas flow injection time.

    PubMed

    Eum, Jun-Ho; Kim, Sung-Hoon; Yi, Soung Soo; Jang, Kiwan

    2012-05-01

    Carbon coils could be synthesized using C2H2/H2 as source gases and SF6 as an incorporated additive gas under thermal chemical vapor deposition system. Nickel catalyst layer deposition and then hydrogen plasma pretreatment were performed prior to the carbon coils deposition reaction. According to the different reaction processes, the injection time of SF6 gas flow was varied. The characteristics (formation density, morphology, and geometry) of the deposited carbon coils on the substrates were investigated according to the different reaction processes. Finally, the large-scale synthesis of carbon coils and their geometry control could be achieved merely by manipulating SF6 gas flow injection time. Three cases growth aspects were proposed according to SF6 gas flow injection time in association with the fluorine's characteristics for etching the materials or enhancing the nucleation sites.

  9. DDR-type zeolite membrane synthesis, modification and gas permeation studies

    SciTech Connect

    Yang, Shaowei; Cao, Zishu; Arvanitis, Antonios; Sun, Xinhui; Xu, Zhi; Dong, Junhang

    2016-01-22

    DDR-type zeolite membrane was synthesized on porous α-alumina substrate by hydrothermal treatment of a ball-milled Sigmal-1 crystal seed layer in an aluminum-free precursor solution containing 1-Adamantylamine as the structure directing agent (SDA). The as-synthesized DDR zeolite membranes were defect-free but the supported zeolite layers were susceptible to crack development during the subsequent high-temperature SDA removal process. The cracks were effectively eliminated by the liquid phase chemical deposition method using tetramethoxysilane as the precursor for silica deposits. The modified membrane was extensively studied for H2, He, O2, N2, CO2, CH4, and i-C4H10 pure gas permeation and CO2/CH4 mixture separation. At 297 K and 2-bar feed gas pressure, the membrane achieved a CO2/CH4 separation factor of ~92 for a feed containing 90% CO2, which decreased to 62 for a feed containing 10% CO2 with the CO2 permeance virtually unchanged at ~1.8×10–7 mol/m• sup>2 s • Pa regardless of the feed composition. It also exhibited an O2/N2 permselectivity of 1.8 at 297 K. Furthermore, the gas permeation behaviors of the current aluminum-containing DDR type zeolite membrane are generally in good agreement with the findings in both experimental and theoretical studies on the pure-silica DDR membranes in recent literature.

  10. DDR-type zeolite membrane synthesis, modification and gas permeation studies

    DOE PAGES

    Yang, Shaowei; Cao, Zishu; Arvanitis, Antonios; ...

    2016-01-22

    DDR-type zeolite membrane was synthesized on porous α-alumina substrate by hydrothermal treatment of a ball-milled Sigmal-1 crystal seed layer in an aluminum-free precursor solution containing 1-Adamantylamine as the structure directing agent (SDA). The as-synthesized DDR zeolite membranes were defect-free but the supported zeolite layers were susceptible to crack development during the subsequent high-temperature SDA removal process. The cracks were effectively eliminated by the liquid phase chemical deposition method using tetramethoxysilane as the precursor for silica deposits. The modified membrane was extensively studied for H2, He, O2, N2, CO2, CH4, and i-C4H10 pure gas permeation and CO2/CH4 mixture separation. At 297more » K and 2-bar feed gas pressure, the membrane achieved a CO2/CH4 separation factor of ~92 for a feed containing 90% CO2, which decreased to 62 for a feed containing 10% CO2 with the CO2 permeance virtually unchanged at ~1.8×10–7 mol/m• sup>2 s • Pa regardless of the feed composition. It also exhibited an O2/N2 permselectivity of 1.8 at 297 K. Furthermore, the gas permeation behaviors of the current aluminum-containing DDR type zeolite membrane are generally in good agreement with the findings in both experimental and theoretical studies on the pure-silica DDR membranes in recent literature.« less

  11. Iron catalyst for preparation of polymethylene from synthesis gas and method for producing the catalyst

    DOEpatents

    Sapienza, Richard S.; Slegeir, William A.

    1990-01-01

    This invention relates to a process for synthesizing hydrocarbons; more particularly, the invention relates to a process for synthesizing long-chain hydrocarbons known as polymethylene from carbon monoxide and hydrogen or from carbon monoxide and water or mixtures thereof in the presence of a catalyst comprising iron and platinum or palladium or mixtures thereof which may be supported on a solid material, preferably an inorganic refractory oxide. This process may be used to convert a carbon monoxide containing gas to a product which could substitute for high density polyethylene.

  12. Iron catalyst for preparation of polymethylene from synthesis gas and method for producing the catalyst

    DOEpatents

    Sapienza, R.S.; Slegeir, W.A.

    1990-05-15

    This invention relates to a process for synthesizing hydrocarbons; more particularly, the invention relates to a process for synthesizing long-chain hydrocarbons known as polymethylene from carbon monoxide and hydrogen or from carbon monoxide and water or mixtures thereof in the presence of a catalyst comprising iron and platinum or palladium or mixtures thereof which may be supported on a solid material, preferably an inorganic refractory oxide. This process may be used to convert a carbon monoxide containing gas to a product which could substitute for high density polyethylene.

  13. Improved sensitivity and selectivity of pristine zinc oxide nanostructures to H2S gas: Detailed study on the synthesis reaction time

    NASA Astrophysics Data System (ADS)

    Motaung, David E.; Mhlongo, Gugu H.; Bolokang, Amogelang S.; Dhonge, Baban P.; Swart, Hendrik C.; Sinha Ray, Suprakas

    2016-11-01

    The gas sensing properties of ZnO nanostructures synthesized at various reaction times are reported in this study. The response of ZnO nanostructures to H2, NH3, H2S and NO2 gases was investigated at different operating temperatures and gas concentrations. Surface morphology analyses showed that the geometry of the nanostructures transforms with the synthesis reaction time. Topography analyses demonstrated a surface roughness of approximately 68.25, 70.31, 74.75 nm for the samples synthesized for 24, 48 and 72 h, respectively. The dependence of the morphology on the H2, NH3, NO2 and H2S gas sensing performance was observed. The alteration of the nanostructures diameter/geometry demonstrated a change in both the magnitude and temperature of the maximum sensor response. The 72 h ZnO sensing material revealed improved response and higher sensitivity and selectivity to H2S gas, while the 24 h sensing material revealed enhanced response and selectivity to NO2 gas at 300 °C. Moreover, the 72 h sensing material exhibited a higher sensitivity of 144.22 ppm-1 at 300 °C. These findings disclosed that by varying the synthesis reaction time, the sensing properties, such as the response, sensitivity and selectivity of the ZnO nanostructures could be tuned.

  14. Nickel oxide nanowires: vapor liquid solid synthesis and integration into a gas sensing device

    NASA Astrophysics Data System (ADS)

    Kaur, N.; Comini, E.; Zappa, D.; Poli, N.; Sberveglieri, G.

    2016-05-01

    In the field of advanced sensor technology, metal oxide nanostructures are promising materials due to their high charge carrier mobility, easy fabrication and excellent stability. Among all the metal oxide semiconductors, nickel oxide (NiO) is a p-type semiconductor with a wide band gap and excellent optical, electrical and magnetic properties, which has not been much investigated. Herein, we report the growth of NiO nanowires by using the vapor liquid solid (VLS) technique for gas sensing applications. Platinum, palladium and gold have been used as a catalyst for the growth of NiO nanowires. The surface morphology of the nanowires was investigated through scanning electron microscopy to find out which catalyst and growth conditions are best for the growth of nanowires. GI-XRD and Raman spectroscopies were used to confirm the crystalline structure of the material. Different batches of sensors have been prepared, and their sensing performances towards different gas species such as carbon monoxide, ethanol, acetone and hydrogen have been explored. NiO nanowire sensors show interesting and promising performances towards hydrogen.

  15. Synthesis, characterization and gas sensing properties of novel homo and hetero dinuclear ball-type phthalocyanines.

    PubMed

    Kakı, Esra; Altındal, Ahmet; Salih, Bekir; Bekaroğlu, Özer

    2015-05-07

    New ball-type homodinuclear Co(ii)-Co(ii) phthalocyanine () and ball-type heterodinuclear Co(ii)-Fe(ii) phthalocyanine () were synthesized from the corresponding [2,10,16,24-tetrakis{4,4'-cyclohexylidenebis(2-cyclohexyphenoxyphthalonitrile)}phthalocyaninatocobalt(ii)] (). The novel compounds have been characterized by elemental analysis, IR, UV-Vis and MALDI-TOF mass spectroscopy. Gas sensing capability of the spin coated film of and were studied using amperometric technique at various temperatures. For a better understanding of the interaction of and films with organic compounds, two different groups of compounds (aromatics and alcohols) were selected as test analytes. It was observed that the operating temperature had a considerable effect on the gas sensing performance of the sensors investigated. The experimental results show that film offers a promising perspective as a sensing material for the detection of relatively low aromatic vapours even at room temperature. This suggests that aromatics might be distinguished from alcohols. The obtained data were analysed using two different adsorption kinetic models: the pseudo first order equation and Elovich equation to determine the best fit equation for the adsorption of toluene vapor onto and films. The first-order equation was the best of the various kinetic models studied to describe the adsorption kinetic of toluene on Pc films at higher concentrations, as evidenced by the highest correlation coefficients. In addition, it was observed that Elovich equation generates a straight line that best fit to the data of adsorption of lower concentrations of toluene.

  16. Biological conversion of synthesis gas. Project status report, October 1, 1992--December 31, 1992

    SciTech Connect

    Ackerson, M.D.; Clausen, E.C.; Gaddy, J.L.

    1993-01-05

    Syngas is known to contain approximately 1 percent H{sub 2}S, along with CO{sub 2}, C0{sub 2}, H{sub 2} and CH{sub 4}. Similarly, the syngas may become contaminated with oxygen, particularly during reactor start-up and during maintenance. Previous studies with the water-gas shift bacterium Rhodospirillum rubrum have shown that the bacterium is tolerant of small quantities of oxygen, but the effects of oxygen on CO-consumption are unknown. Similarly, R. rubrum is known to be tolerant of H{sub 2}S, with high concentrations of H{sub 2}S negatively affecting CO-uptake. Batch experiments were thus carried out to determine the effects of H{sub 2}S and O{sub 2} on CO-uptake by R. rubrum. The results of these experiments were quantified by using Monod equations modified by adding terms for CO, H{sub 2}S and O{sub 2} inhibition. The techniques used in determining kinetic expressions previously shown for other gas-phase substrate bacterial systems including R. rubrum were utilized.

  17. Synthesis and analysis of nanostructured composite particles from gas-saturated solutions

    NASA Astrophysics Data System (ADS)

    Gil'mutdinov, I. I.; Gil'mutdinov, I. M.; Kuznetsova, I. V.; Sabirzyanov, A. N.

    2015-05-01

    Ibuprofen/polyethylene glycol 4000 and methylparaben/polyethylene glycol 4000 nanostructured composite particles are synthesized from gas-saturated solutions (PGSS, particles from gas saturated solution). The dependences of the mean size of composite particles on pressure, temperature, and the expansion channel diameter are revealed. The studies are conducted in the pressure range of 10 to 30 MPa, at temperatures ranging from 40 to 80°C, and for expansion channel diameters in the range of 200 to 500 μm. The physicochemical properties of the composite particles are investigated using a differential scanning calorimeter and phase analysis is performed by means of X-ray diffraction. The composition of composite particles is determined via mass spectrometric analysis. Chromatography-tandem mass spectrometry with electronic ionization is used for the quantitative analysis of ibuprofen, while mass spectrometry of matrix-assisted laser desorption/ionization (MALDI) is used in the analysis of polyethylene glycol 4000. The dependence of the concentration of components in composite particles on pressure is obtained.

  18. Biological conversion of synthesis gas. Final report, August 31, 1990--September 3, 1993

    SciTech Connect

    Basu, R.; Klasson, K.T.; Johnson, E.R.; Takriff, M.; Clausen, E.C.; Gaddy, J.L.

    1993-09-01

    Based upon the results of this culture screening study, Rhodospirillum rubrum is recommended for biocatalysis of the water gas shift reaction and Chlorobium thiosulfatophilum is recommended for H{sub 2}S conversion to elemental sulfur. Both bacteria require tungsten light for growth and can be co-cultured together if H{sub 2}S conversion is not complete (required concentration of at least 1 ppM), thereby presenting H{sub 2} uptake by Chlorobium thiosulfatophilum. COS degradation may be accomplished by utilizing various CO-utilizing bacteria or by indirectly converting COS to elemental sulfur after the COS first undergoes reaction to H{sub 2} in water. The second alternative is probably preferred due to the low expected concentration of COS relative to H{sub 2}S. Mass transfer and kinetic studies were carried out for the Rhodospirillum rubrum and Chlorobium thiosulfatophilum bacterial systems. Rhodospirillum rubrum is a photosynthetic anaerobic bacterium which catalyzes the biological water gas shift reaction: CO + H{sub 2}O {yields} CO{sub 2} + H{sub 2}. Chlorobium thiosulfatophilum is also a photosynthetic anaerobic bacteria, and converts H{sub 2}S and COS to elemental sulfur.

  19. Efficient utilization of greenhouse gases in a gas-to-liquids process combined with CO2/steam-mixed reforming and Fe-based Fischer-Tropsch synthesis.

    PubMed

    Zhang, Chundong; Jun, Ki-Won; Ha, Kyoung-Su; Lee, Yun-Jo; Kang, Seok Chang

    2014-07-15

    Two process models for carbon dioxide utilized gas-to-liquids (GTL) process (CUGP) mainly producing light olefins and Fischer-Tropsch (F-T) synthetic oils were developed by Aspen Plus software. Both models are mainly composed of a reforming unit, an F-T synthesis unit and a recycle unit, while the main difference is the feeding point of fresh CO2. In the reforming unit, CO2 reforming and steam reforming of methane are combined together to produce syngas in flexible composition. Meanwhile, CO2 hydrogenation is conducted via reverse water gas shift on the Fe-based catalysts in the F-T synthesis unit to produce hydrocarbons. After F-T synthesis, the unreacted syngas is recycled to F-T synthesis and reforming units to enhance process efficiency. From the simulation results, it was found that the carbon efficiencies of both CUGP options were successfully improved, and total CO2 emissions were significantly reduced, compared with the conventional GTL processes. The process efficiency was sensitive to recycle ratio and more recycle seemed to be beneficial for improving process efficiency and reducing CO2 emission. However, the process efficiency was rather insensitive to split ratio (recycle to reforming unit/total recycle), and the optimum split ratio was determined to be zero.

  20. Guanidinophosphazenes: design, synthesis, and basicity in THF and in the gas phase.

    PubMed

    Kolomeitsev, Alexander A; Koppel, Ilmar A; Rodima, Toomas; Barten, Jan; Lork, Enno; Röschenthaler, Gerd-Volker; Kaljurand, Ivari; Kütt, Agnes; Koppel, Ivar; Mäemets, Vahur; Leito, Ivo

    2005-12-21

    A principle for creating a new generation of nonionic superbases is presented. It is based on attachment of tetraalkylguanidino, 1,3-dimethylimidazolidine-2-imino, or bis(tetraalkylguanidino)carbimino groups to the phosphorus atom of the iminophosphorane group using tetramethylguanidine or easily available 1,3-dimethylimidazolidine-2-imine. Seven new nonionic superbasic phosphazene bases, tetramethylguanidino-substituted at the P atom, have been synthesized. Their base strengths are established in tetrahydrofuran (THF) solution by means of spectrophotometric titration and compared with those of eight reference superbases designed specially for this study, P2- and P4-iminophosphoranes. The gas-phase basicities of several guanidino- and N',N',N'',N''-tetramethylguanidino (tmg)-substituted phosphazenes and their cyclic analogues are calculated, and the crystal structures of (tmg)3P=N-t-Bu and (tmg)3P=N-t-Bu x HBF4 are determined. The enormous basicity-increasing effect of this principle is experimentally verified for the tetramethylguanidino groups in the THF medium: the basicity increase when moving from (dma)3P=N-t-Bu (pKalpha = 18.9) to (tmg)3P=N-t-Bu (pKalpha = 29.1) is 10 orders of magnitude. A significantly larger basicity increase (up to 20 powers of 10) is expected (based on the high-level density functional theory calculations) to accompany the similar gas-phase transfer between the (dma)3P=NH and (tmg)3P=NH bases. Far stronger basicities still are expected when, in the latter two compounds, all three dimethylamino (or tetramethylguanidino) fragments are replaced by methylated triguanide fragments, (tmg)2C=N-. The gas-phase basicity (around 300-310 kcal/mol) of the resulting base, [(tmg)2C=N-]3P=NH, having only one phosphorus atom, is predicted to exceed the basicity of (dma)3P=NH by more than 40 powers of 10 and to surpass also the basicity of the widely used commercial [(dma)3P=N]3P=N-t-Bu (t-BuP4) superbase.

  1. Isobutanol-methanol mixtures from synthesis gas. Quarterly technical progress report, October 1--December 31, 1995

    SciTech Connect

    Iglesia, E.

    1996-01-10

    A series of Cu{sub 0.5}CeMe(II)O{sub x} catalysts (Me refers to Group II alkali earth elements) have been prepared by coprecipitating the corresponding metal nitrates with potassium carbonate. The bulk composition of the catalyst has been determined by atomic absorption (AA) analysis. High-pressure isobutanol synthesis studies have been carried out over a standard BASF Cs-promoted Cu/ZnO/Al{sub 2}O{sub 3} catalyst. At a CO conversion level of 32%, the isobutanol carbon selectivity is about 5%; whereas that of methanol is 40.2%. A 100% selectivity sum has now been obtained as a result of using response factors measured by the laboratory. The reactions of ethanol and acetic acid over a number of catalysts have been investigated using a temperature programmed surface reaction (TPSR) technique. Ethanol and acetone are the only desorption products observed over Cs-promoted Cu/ZnO/Al{sub 2}O{sub 3} catalysts. Surface acetate ion is believed to be the precursor for acetone formation. Over calcined hydrotalcites, i.e., MgO/Al{sub 2}O{sub 3}, ethylene is formed instead of acetone. The amount of ethylene formed decreases as Mg/Al ratio increases, suggesting a role of aluminum ions in ethanol dehydration reactions.

  2. Isobutanol-methanol mixtures from synthesis gas. Quarterly report, July 1 - September 30, 1996

    SciTech Connect

    Iglesia, E.

    1996-12-01

    A series of CuMgCeO{sub x} catalysts have been prepared by coprecipitating the corresponding metal nitrates with a mixed solution of potassium carbonate and potassium hydroxide. The bulk composition of the catalyst has been measured by atomic absorption (AA) analysis and the Cu dispersion has been determined by N{sub 2}O titration at 90 {degrees}C. CeO{sub x} does not contribute to the measured copper dispersion in K-CuO{sub 0.5}Mg{sub 5}CeO{sub x} samples and the high dispersion value indeed reflects the presence of Cu metal small crystallites. Kinetic studies of methanol and propionaldehyde coupling reactions on K-Cu/MgO/CeO{sub 2} and MgO/CeO{sub 2} catalysts indicate that Cu enhances the rates of alcohol dehydrogenation. High-pressure isobutanol synthesis from CO/H{sub 2} has been studied on CuO{sub 0.5}Mg{sub 5}O{sub x} catalysts at 593 K and 4.5 MPa. CuO{sub 0.5}Mg{sub 5}O{sub x} catalysts show high hydrocarbon and low isobutanol selectivities compared to K-CuO{sub 0.5}Mg{sub 5}CeO{sub x}, suggesting the presence of residual acidity in CuO{sub 0.5}Mg{sub 5}O{sub x}.

  3. Hydrothermal synthesis of assembled sphere-like WO3 architectures and their gas-sensing properties

    NASA Astrophysics Data System (ADS)

    Zhang, Hejing; Liu, Tianmo; Huang, Long; Guo, Weiwei; Liu, Dejun; Zeng, Wen

    2012-04-01

    Unique assembled sphere-like WO3 architectures were successfully synthesized through a facile hydrothermal method in the presence of malic acid followed by subsequent heat treatment. We found that malic acid played a significant role in governing morphologies of WO3·xH2O precursors during hydrothermal process. A possible formation mechanism was also proposed in detail. Experimental results showed that the optimized hydrothermal precursor could be dehydrated to mixed composition of hexagonal and monoclinic WO3 with the unique sphere-like porous architecture after being annealed at 400 °C for 2.5 h. Besides, gas-sensing measurement indicated that the well-defined 3D assembled sphere-like architectures exhibited the highest sensor response to ethanol at the optimal temperature of 250 °C among the samples.

  4. Synthesis of nanostructured copper oxide via oxalate precursors and their sensing properties for hydrogen cyanide gas.

    PubMed

    Yang, Mingqing; He, Junhui; Hu, Xiaochun; Yan, Chunxiao; Cheng, Zhenxing

    2013-03-21

    In this work, nanostructured copper oxide of varied morphologies and high surface area were prepared by calcination of copper oxalate precursors, and were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis and differential thermal analysis, and nitrogen adsorption-desorption measurements. The sphere-like CuO (specific surface area: 73 m(2) g(-1)) functionalized QCM resonators were fabricated and explored for HCN sensing. The sensitivity (10 s HCN exposure) of sphere-like CuO functionalized QCM resonators reached as high as 6.53 Hz μg(-1). The reproducibility and stability of sphere-like CuO functionalized QCM resonators was excellent, and the selectivity was very high with a converse response to examined common chemicals. The high surface area CuO functionalized QCM sensors may be applicable for HCN gas sensing.

  5. Synthesis of Cu nanoparticles with self-assembled monolayers via inert-gas condensation.

    PubMed

    Kang, Min-Kyu; Kim, Jong-Woong; Kwak, Min-Gi; Yoon, Ho-Gyu; Kim, Young-Seok

    2011-07-01

    Cu nanoparticles with vaporized self-assembled monolayers (SAMs) for the prevention of oxidation were synthesized via inert-gas condensation (IGC). When processing the nanoparticles, the convection in the vacuum chamber was controlled using carrier gases such as Ar and He. Cu shots (2-8 mm) were used as raw materials and were evaporated via resistance heating. Octanethiol (CH3(CH2)7SH) was used for the SAMs and was introduced with the carrier gases during the process. The prepared samples were examined via scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to determine the particle sizes, the coating thicknesses of the SAMs, and the particle distribution states. The ingredients were confirmed via X-ray photoelectron spectroscopy (XPS) and energy-dispersive spectroscopy (EDS). The particle size and morphology were controlled by introducing various combinations of carrier gases, such as He, Ar and H2. Finally, stabilized Cu nanoparticles stably coated with octanethiol were successfully fabricated.

  6. Microbial synthesis gas utilization and ways to resolve kinetic and mass-transfer limitations.

    PubMed

    Yasin, Muhammad; Jeong, Yeseul; Park, Shinyoung; Jeong, Jiyeong; Lee, Eun Yeol; Lovitt, Robert W; Kim, Byung Hong; Lee, Jinwon; Chang, In Seop

    2015-02-01

    Microbial conversion of syngas to energy-dense biofuels and valuable chemicals is a potential technology for the efficient utilization of fossils (e.g., coal) and renewable resources (e.g., lignocellulosic biomass) in an environmentally friendly manner. However, gas-liquid mass transfer and kinetic limitations are still major constraints that limit the widespread adoption and successful commercialization of the technology. This review paper provides rationales for syngas bioconversion and summarizes the reaction limited conditions along with the possible strategies to overcome these challenges. Mass transfer and economic performances of various reactor configurations are compared, and an ideal case for optimum bioreactor operation is presented. Overall, the challenges with the bioprocessing steps are highlighted, and potential solutions are suggested. Future research directions are provided and a conceptual design for a membrane-based syngas biorefinery is proposed.

  7. GAS-PHASE FLAME SYNTHESIS AND PROPERTIES OF MAGNETIC IRON OXIDE NANOPARTICLES WITH REDUCED OXIDATION STATE

    PubMed Central

    Kumfer, Benjamin M; Shinoda, Kozo; Jeyadevan, Balachandran; Kennedy, Ian M

    2010-01-01

    Iron oxide nanoparticles of reduced oxidation state, mainly in the form of magnetite, have been synthesized utilizing a new continuous, gas-phase, nonpremixed flame method using hydrocarbon fuels. This method takes advantage of the characteristics of the inverse flame, which is produced by injection of oxidizer into a surrounding flow of fuel. Unlike traditional flame methods, this configuration allows for the iron particle formation to be maintained in a more reducing environment. The effects of flame temperature, oxygen-enrichment and fuel dilution (i.e. the stoichiometric mixture fraction), and fuel composition on particle size, Fe oxidation state, and magnetic properties are evaluated and discussed. The crystallite size, Fe(II) fraction, and saturation magnetization were all found to increase with flame temperature. Flames of methane and ethylene were used, and the use of ethylene resulted in particles containing metallic Fe(0), in addition to magnetite, while no Fe(0) was present in samples synthesized using methane. PMID:20228941

  8. Gas phase synthesis of core-shell Fe@FeO x magnetic nanoparticles into fluids

    NASA Astrophysics Data System (ADS)

    Aktas, Sitki; Thornton, Stuart C.; Binns, Chris; Denby, Phil

    2016-12-01

    Sorbitol, short chain molecules, have been used to stabilise of Fe@FeO x nanoparticles produced in the gas phase under the ultra-high vacuum (UHV) conditions. The sorbitol coated Fe@FeO x nanoparticles produced by our method have a narrow size distribution with a hydrodynamic diameter of 35 nm after NaOH is added to the solution. Magnetisation measurement shows that the magnetic nanoparticles are superparamagnetic at 100 K and demonstrate hysteresis at 5 K with an anisotropy constant of 5.31 × 104 J/m3 (similar to bulk iron). Also, it is shown that sorbitol is only suitable for stabilising the Fe@FeO x suspensions, and it does not prevent further oxidation of the metallic Fe core. According to MRI measurement, the nanoparticles have a high transverse relaxation rate of 425 mM-1 s-1.

  9. Synthesis of nanowires via helium and neon focused ion beam induced deposition with the gas field ion microscope.

    PubMed

    Wu, H M; Stern, L A; Chen, J H; Huth, M; Schwalb, C H; Winhold, M; Porrati, F; Gonzalez, C M; Timilsina, R; Rack, P D

    2013-05-03

    The ion beam induced nanoscale synthesis of platinum nanowires using the trimethyl (methylcyclopentadienyl)platinum(IV) (MeCpPt(IV)Me3) precursor is investigated using helium and neon ion beams in the gas field ion microscope. The He(+) beam induced deposition resembles material deposited by electron beam induced deposition with very small platinum nanocrystallites suspended in a carbonaceous matrix. The He(+) deposited material composition was estimated to be 16% Pt in a matrix of amorphous carbon with a large room-temperature resistivity (∼3.5 × 10(4)-2.2 × 10(5) μΩ cm) and temperature-dependent transport behavior consistent with a granular material in the weak intergrain tunnel coupling regime. The Ne(+) deposited material has comparable composition (17%), however a much lower room-temperature resistivity (∼600-3.0 × 10(3) μΩ cm) and temperature-dependent electrical behavior representative of strong intergrain coupling. The Ne(+) deposited nanostructure has larger platinum nanoparticles and is rationalized via Monte Carlo ion-solid simulations which show that the neon energy density deposited during growth is much larger due to the smaller ion range and is dominated by nuclear stopping relative to helium which has a larger range and is dominated by electronic stopping.

  10. Nitrogen metabolism and gas exchange parameters associated with zinc stress in tobacco expressing an ipt gene for cytokinin synthesis.

    PubMed

    Pavlíková, Daniela; Pavlík, Milan; Procházková, Dagmar; Zemanová, Veronika; Hnilička, František; Wilhelmová, Naďa

    2014-04-15

    Increased endogenous plant cytokinin (CK) content through transformation with an isopentyl transferase (ipt) gene has been associated with improved plant stress tolerance. The impact of zinc (tested levels Zn1=250, Zn2=500, Zn3=750mgkg(-1)soil) on gas exchange parameters (net photosynthetic rate, transpiration rate, stomatal conductance, intercellular CO2 concentration) and nitrogen utilization by plants resulted in changes of free amino acid concentrations (glutamic acid, glutamine, asparagine, aspartate, glycine, serine, cystein) and differed for transformed and non-transformed tobacco plants. For pot experiments, tobacco plants (Nicotiana tabacum L., cv. Wisconsin 38) transformed with a construct consisting of SAG12 promoter fused with the ipt gene for cytokinin synthesis (SAG plants) and its wild type (WT plants as a control) were used. Physiological analyses confirmed that SAG plants had improved zinc tolerance compared with the WT plants. The enhanced Zn tolerance of SAG plants was associated with the maintenance of accumulation of amino acids and with lower declines of photosynthetic and transpiration rates. In comparison to WT plants, SAG plants exposed to the highest Zn concentration accumulated lower concentrations of asparagine, which is a major metabolic product during senescence.

  11. Ethanol synthesis and water gas shift over bifunctional sulfide catalysts. Technical progress report, June 1993--August 1993

    SciTech Connect

    Klier, K.; Herman, R.G.; Deemer, M.; Carr, T.

    1993-09-01

    Various preparation methods of synthesizing molybdenum disulfide and various alkali doping procedures were studied to determine if various preparation paramenters affected catalyst activity. Testing was performed on an undoped molybdenum disulfide sample with H{sub 2}/CO = 1 synthesis gas at 8.1 MPa and at temperatures of 245, 255, 265, 275, 280, 300, 320, and 295C, and only hydrocarbons were formed. A methanol injection experiment with undoped catalyst showed that homologation of methanol did not occur over the undoped MOS{sub 2}. Catalytic testing on a cesium formate doped molybdenum disulfide catalyst corresponding to 9 wt% Cs/MoS{sub 2} at 8.1 MPa and temperatures of 245, 255, 265, 275, 285, and 295C, mostly linear alcohols. The CS/MOS{sub 2} sample was protected from air exposure during preparation and testiag. As with the other recently tested alkali-promoted MOS{sub 2} catalysts, this cataylst was not as active as previous CS/MOS{sub 2} catalysts [1], and some deactivation during these systematic studies was observed. X-Ray powder diffraction and BET surface area measurements are being used to characterize the catalysts, and electron microscopy analyses are being carried out.

  12. Gas-phase synthesis of Mg-Ti nanoparticles for solid-state hydrogen storage.

    PubMed

    Calizzi, M; Venturi, F; Ponthieu, M; Cuevas, F; Morandi, V; Perkisas, T; Bals, S; Pasquini, L

    2016-01-07

    Mg-Ti nanostructured samples with different Ti contents were prepared via compaction of nanoparticles grown by inert gas condensation with independent Mg and Ti vapour sources. The growth set-up offered the option to perform in situ hydrogen absorption before compaction. Structural and morphological characterisation was carried out by X-ray diffraction, energy dispersive spectroscopy and electron microscopy. The formation of an extended metastable solid solution of Ti in hcp Mg was detected up to 15 at% Ti in the as-grown nanoparticles, while after in situ hydrogen absorption, phase separation between MgH2 and TiH2 was observed. At a Ti content of 22 at%, a metastable Mg-Ti-H fcc phase was observed after in situ hydrogen absorption. The co-evaporation of Mg and Ti inhibited nanoparticle coalescence and crystallite growth in comparison with the evaporation of Mg only. In situ hydrogen absorption was beneficial to subsequent hydrogen behaviour, studied by high pressure differential scanning calorimetry and isothermal kinetics. A transformed fraction of 90% was reached within 100 s at 300 °C during both hydrogen absorption and desorption. The enthalpy of hydride formation was not observed to differ from bulk MgH2.

  13. Molecular uranates - laser synthesis of uranium oxide anions in the gas phase

    SciTech Connect

    Marcalo, Joaquim; Santos, Marta; Pires de Matos, Antonio; Gibson, John K

    2009-12-14

    Laser ablation of solid UO{sub 3} or (NH{sub 4}){sub 2}U{sub 2}O{sub 7} yielded in the gas phase molecular uranium oxide anions with compositions ranging from [UO{sub n}]{sup -} (n = 2-4) to [U{sub 14}O{sub n}]{sup -} (n = 32-35), as detected by Fourier transform ion cyclotron resonance mass spectrometry. The cluster series [U{sub x}O{sub 3x}]{sup -} for x {le} 6 and various [U{sub x}O{sub 3x-y}]{sup -}, in which y increased with increasing x, could be identified. A few anions with H atoms were also present, and their abundance increased when hydrated UO{sub 3} was used in place of anhydrous UO{sub 3}. Collision-induced dissociation experiments with some of the lower m/z cluster anions supported extended structures in which neutral UO{sub 3} constitutes the building block. Cationic uranium oxide clusters [U{sub x}O{sub n}]{sup +} (x = 2-9; n = 3-24) could also be produced and are briefly discussed. Common trends in the O/U ratios for both negative and positive clusters could be unveiled.

  14. Gas assisted method synthesis nitrogen-doped carbon quantum dots and Hg (II) sensing.

    PubMed

    Li, Yamei; Wang, Nan; He, Zhanhang

    2016-11-29

    Nitrogen-doped fluorescent carbon quantum dots (CQDs) was prepared by gas-assisted method using cellulose as precursors under ammonia atmosphere, which not only exhibited excellent photoluminescent properties, but also showed highly selective and sensitive detection of mercury ion. The nitrogen-doped CQDs displayed excitation wavelength dependent fluorescent behavior with outstanding dispersibility. Moreover, they exhibited high tolerance to various external conditions, such as storage time, pH value, and ionic strength. The rapid detection of Hg (II) by one-step operation within 1 min and the good linear correlation between I0/I and Hg (II) concentration in the range of 10-100 nM made the nitrogen-doped CQDs a promising nanoprobe for Hg (II) detection. The detection limit of the nitrogen-doped CQDs is about 7.7 nM. Such a nanoprobe has been successfully applied for the analysis of Hg (II) in natural water samples, demonstrating excellent practical feasibility.

  15. Synthesis, structure and bonding of actinide disulphide dications in the gas phase.

    PubMed

    Lucena, Ana F; Bandeira, Nuno A G; Pereira, Cláudia C L; Gibson, John K; Marçalo, Joaquim

    2017-04-11

    Actinide disulphide dications, AnS2(2+), were produced in the gas phase for An = Th and Np by reaction of An(2+) cations with the sulfur-atom donor COS, in a sequential abstraction process of two sulfur atoms, as examined by FTICR mass spectrometry. For An = Pu and Am, An(2+) ions were unreactive with COS and did not yield any sulphide species. High level multiconfigurational (CASPT2) calculations were performed to assess the structures and bonding of the new AnS2(2+) species obtained for An = Th, Np, as well as for An = Pu to examine trends along the An series, and for An = U to compare with a previous experimental study and DFT computational scrutiny of US2(2+). The CASPT2 results showed that, like in the case of uranium, the new AnS2(2+) ions have ground states with triangular geometries, corresponding to the presence of a persulphide in the case of thorium that formally leads to a stable Th(IV)S2(2+) species, while a supersulphide appears to be present in the case of U, Np and Pu, formally leading to a An(III)S2(2+) species. The computations also revealed that linear thioactinyl structures are higher in energy, with a difference that increases fourfold upon moving from U to Pu, apparently indicating that it will be even more pronounced for Am.

  16. Green synthesis of highly reduced graphene oxide by compressed hydrogen gas towards energy storage devices

    NASA Astrophysics Data System (ADS)

    Li, Cheng Chao; Yu, Hong; Yan, Qingyu; Hng, Huey Hoon

    2015-01-01

    Herein, we present a new strategy for the mass production of high-quality reduced graphene oxide (RGO) with a surface area of 354 m2 g-1 using high pressure hydrogen as a reducing agent under hydrothermal conditions. The high pressure used is solely generated from the packing of the gas cylinder itself and a pressure meter could simply fulfil the role of monitoring pressure. The reduction process is green without chemical wastes produced. Comparing to other reported methods, the significant advancements of our strategy lie not only in the high-quality RGO with high C/O ratio, conductivity and surface area, but also in the most environment-friendliness and cost-effectiveness, which make the large scale fabrication feasible. Moreover, clean noble metal nanocrystals such as Pt could be easily in situ deposited onto the surface of RGO nanosheets when noble metal salts are introduced into the system. In particular, the prepared RGO and Pt/RGO show exceptional electrochemical performances in supercapacitors and lithium oxygen batteries because of their clean electrochemical surface, good conductivity and large surface area. Our results reveal that the obtained RGO have a specific capacitance of 884.4 F g-1 at a current density of 0.5 A g-1, and the Pt/RGO electrode can deliver discharge-charge capacities of 1000 mAh g-1 for 40 cycles with a high round-trip efficiencies of 74.9% at 50 mA g-1 when used as Li-O2 battery electrodes.

  17. Dual Layer Monolith ATR of Pyrolysis Oil for Distributed Synthesis Gas Production

    SciTech Connect

    Lawal, Adeniyi

    2012-09-29

    We have successfully demonstrated a novel reactor technology, based on BASF dual layer monolith catalyst, for miniaturizing the autothermal reforming of pyrolysis oil to syngas, the second and most critical of the three steps for thermochemically converting biomass waste to liquid transportation fuel. The technology was applied to aged as well as fresh samples of pyrolysis oil derived from five different biomass feedstocks, namely switch-grass, sawdust, hardwood/softwood, golden rod and maple. Optimization of process conditions in conjunction with innovative reactor system design enabled the minimization of carbon deposit and control of the H2/CO ratio of the product gas. A comprehensive techno-economic analysis of the integrated process using in part, experimental data from the project, indicates (1) net energy recovery of 49% accounting for all losses and external energy input, (2) weight of diesel oil produced as a percent of the biomass to be ~14%, and (3) for a demonstration size biomass to Fischer-Tropsch liquid plant of ~ 2000 daily barrels of diesel, the price of the diesel produced is ~$3.30 per gallon, ex. tax. However, the extension of catalyst life is critical to the realization of the projected economics. Catalyst deactivation was observed and the modes of deactivation, both reversible and irreversible were identified. An effective catalyst regeneration strategy was successfully demonstrated for reversible catalyst deactivation while a catalyst preservation strategy was proposed for preventing irreversible catalyst deactivation. Future work should therefore be focused on extending the catalyst life, and a successful demonstration of an extended (> 500 on-stream hours) catalyst life would affirm the commercial viability of the process.

  18. Advanced bioreactor systems for gaseous substrates: Conversion of synthesis gas to liquid fuels and removal of SO{sub x} and NO{sub x} from coal combustion gases

    SciTech Connect

    Selvaraj, P.T.; Kaufman, E.N.

    1995-06-01

    The purpose of the proposed research program is the development and demonstration of a new generation of gaseous substrate-based bioreactors for the production of liquid fuels from coal synthesis gas and the removal of NO{sub x} and SO{sub x} species from combustion flue gas. Coal is thermochemically converted to synthesis gas consisting of carbon monoxide, hydrogen, and carbon dioxide. Conventional catalytic upgrading of coal synthesis gas into alcohols or other oxychemicals is subject to several processing problems such as interference of the other constituents in the synthesis gases, strict CO/H{sub 2} ratios required to maintain a particular product distribution and yield, and high processing cost due to the operation at high temperatures and pressures. Recently isolated and identified bacterial strains capable of utilizing CO as a carbon source and coverting CO and H{sub 2} into mixed alcohols offer the potential of performing synthesis gas conversion using biocatalysts. Biocatalytic conversion, though slower than the conventional process, has several advantages such as decreased interference of the other constituents in the synthesis gases, no requirement for strict CO/H{sub 2} ratios, and decreased capital and oeprating costs as the biocatalytic reactions occur at ambient temperatures and pressures.

  19. Greenhouse gas fluxes from drained organic soils - a synthesis of a large dataset

    NASA Astrophysics Data System (ADS)

    Tiemeyer, Bärbel

    2016-04-01

    Drained peatlands are hotspots of greenhouse gas (GHG) emissions. Agriculture is the major land use type for peatlands in Germany and other European countries, but strongly varies in its intensity regarding groundwater level and agricultural management. Although the mean annual water table depth is sometimes proposed as an overall predictor for GHG emissions, there is a strong variability of its effects on different peatlands. We synthesized 164 annual GHG budgets for 65 different sites in 13 German peatlands. Land use comprised arable land with different crops (n = 17) and grassland with a management gradient from very intensive use with up to five cuts per year to partially rewetted conservation grassland (n = 48). Carbon dioxide (net ecosystem exchange and ecosystem respiration), nitrous oxide and methane fluxes were measured with transparent and opaque manual chambers. Besides the GHG fluxes, biomass yield, fertilisation, groundwater level, climatic data, vegetation composition and soil properties were measured. Overall, we found a large variability of the total GHG budget ranging from small uptakes to extremely high emissions (> 70 t CO2-equivalents/(ha yr)). At nearly all sites, carbon dioxide was the major component of the GHG budget. Site conditions, especially the nitrogen content of the unsaturated zone and the intra-annual water level distribution, dominated the GHG emissions from grassland. Although these factors are influenced by natural conditions (peat type, regional hydrology), they could be modified by an improved water management. In the case of grassland, agricultural management such as the number of cuts had only a minor influence on the GHG budgets. Given comparable site conditions, there was no significant difference between the emissions from grassland and arable land. Due to the large heterogeneity of site conditions and crop types, emissions from arable land are difficult to explain, but management decisions such as the duration of soil

  20. Facile synthesis of titania nanowires via a hot filament method and conductometric measurement of their response to hydrogen sulfide gas.

    PubMed

    Munz, Martin; Langridge, Mark T; Devarepally, Kishore K; Cox, David C; Patel, Pravin; Martin, Nicholas A; Vargha, Gergely; Stolojan, Vlad; White, Sam; Curry, Richard J

    2013-02-01

    Titania nanostructures are of increasing interest for a variety of applications, including photovoltaics, water splitting, and chemical sensing. Because of the photocatalytical properties of TiO₂, chemical processes that occur at its surface can be exploited for highly efficient nanodevices. A facile and fast synthesis route has been explored that is free of catalysts or templates. An environmental scanning electron microscopy (ESEM) system was employed to grow titania nanowires (NWs) in a water vapor atmosphere (∼1 mbar) and to monitor the growth in situ. In addition, the growth process was also demonstrated using a simple vacuum chamber. In both processes, a titanium filament was heated via the Joule effect and NWs were found to grow on its surface, as a result of thermal oxidation processes. A variety of nanostructures were observed across the filament, with morphologies changing with the wire temperature from the center to the end points. The longest NWs were obtained for temperatures between ∼730 °C and 810 °C. Typically, they have an approximate thickness of ∼300 nm and lengths of up to a few micrometers. Cross sections prepared by focused-ion-beam milling revealed the presence of a porous layer beneath the NW clusters. This indicates that the growth of NWs is driven by oxidation-induced stresses in the subsurface region of the Ti filament and by enhanced diffusion along grain boundaries. To demonstrate the potential of titania NWs grown via the hot filament method, single NW devices were fabricated and used for conductometric sensing of hydrogen sulfide (H₂S) gas. The NW electric resistance was found to decrease in the presence of H₂S. Its variation can be explained in terms of the surface depletion model.

  1. Characterization of the synthesis of N,N-dimethyltryptamine by reductive amination using gas chromatography ion trap mass spectrometry.

    PubMed

    Brandt, Simon D; Moore, Sharon A; Freeman, Sally; Kanu, Abu B

    2010-07-01

    The present study established an impurity profile of a synthetic route to the hallucinogenic N,N-dimethyltryptamine (DMT). The synthesis was carried out under reductive amination conditions between tryptamine and aqueous formaldehyde in the presence of acetic acid followed by reduction with sodium cyanoborohydride. Analytical characterization of this synthetic route was carried out by gas chromatography ion trap mass spectrometry using electron- and chemical-ionization modes. Methanol was employed as a liquid CI reagent and the impact of stoichiometric modifications on side-products formation was also investigated. Tryptamine 1, DMT 2, 2-methyltetrahydro-β-carboline (2-Me-THBC, 3), N-methyl-N-cyanomethyltryptamine (MCMT, 4), N-methyltryptamine (NMT, 5), 2-cyanomethyl-tetrahydro-β-carboline (2-CM-THBC, 6) and tetrahydro-β-carboline (THBC, 7) have been detected under a variety of conditions. Replacement of formaldehyde solution with paraformaldehyde resulted in incomplete conversion of the starting material whereas a similar replacement of sodium cyanoborohydride with sodium borohydride almost exclusively produced THBC instead of the expected DMT. Compounds 1 to 7 were quantified and the limits of detection were 28.4, 87.7, 21.5, 23.4, 41.1, 36.6, and 34.9 ng mL(-1), respectively. The limits of quantification for compounds 1 to 7 were 32.4, 88.3, 25.4, 24.6, 41.4, 39.9, and 37.0 µg mL(-1), respectively. Linearity was observed in the range of 20.8-980 µg mL(-1) with correlation coefficients > 0.99. The application holds great promise in the area of forensic chemistry where development of reliable analytical methods for the detection, identification, and quantification of DMT are crucial and also in pharmaceutical analysis where DMT might be prepared for use in human clinical studies.

  2. Agricultural peatlands: towards a greenhouse gas sink - a synthesis of a Dutch landscape study

    NASA Astrophysics Data System (ADS)

    Schrier-Uijl, A. P.; Kroon, P. S.; Hendriks, D. M. D.; Hensen, A.; Van Huissteden, J.; Berendse, F.; Veenendaal, E. M.

    2014-08-01

    It is generally known that managed, drained peatlands act as carbon (C) sources. In this study we examined how mitigation through the reduction of the intensity of land management and through rewetting may affect the greenhouse gas (GHG) emission and the C balance of intensively managed, drained, agricultural peatlands. Carbon and GHG balances were determined for three peatlands in the western part of the Netherlands from 2005 to 2008 by considering spatial and temporal variability of emissions (CO2, CH4 and N2O). One area (Oukoop) is an intensively managed grass-on-peatland area, including a dairy farm, with the ground water level at an average annual depth of 0.55 (±0.37) m below the soil surface. The second area (Stein) is an extensively managed grass-on-peatland area, formerly intensively managed, with a dynamic ground water level at an average annual depth of 0.45 (±0.35) m below the soil surface. The third area is a (since 1998) rewetted former agricultural peatland (Horstermeer), close to Oukoop and Stein, with the average annual ground water level at a depth of 0.2 (±0.20) m below the soil surface. During the measurement campaigns we found that both agriculturally managed sites acted as C and GHG sources and the rewetted former agricultural peatland acted as a C and GHG sink. The ecosystem (fields and ditches) total GHG balance, including CO2, CH4 and N2O, amounted to 3.9 (±0.4), 1.3 (±0.5) and -1.7 (±1.8) g CO2-eq m-2 d-1 for Oukoop, Stein and Horstermeer, respectively. Adding the farm-based emissions to Oukoop and Stein resulted in a total GHG emission of 8.3 (±1.0) and 6.6 (±1.3) g CO2-eq m-2 d-1, respectively. For Horstermeer the GHG balance remained the same since no farm-based emissions exist. Considering the C balance (uncertainty range 40-60%), the total C release in Oukoop and Stein is 5270 and 6258 kg C ha-1 yr-1, respectively (including ecosystem and management fluxes), and the total C uptake in Horstermeer is 3538 kg C ha-1 yr-1. Water

  3. Novel approaches to the production of higher alcohols from synthesis gas. Quarterly technical progress report No. 18, January 1, 1995-- March 31, 1995

    SciTech Connect

    1996-07-05

    A set of stirrer speed experiments using the Cu/ZnO methanol synthesis catalyst showed that introducing the gas feed into the reactor through an extended dip tube eliminated the dependency of catalyst performance on stirrer speed. The methanol productivity data from the reactor gas feed configuration tests conducted in December, 1994 and January, 1995, were correlated with stirrer speed. The influence on mass transfer on catalyst performance was clearly illustrated for each gas feed location. The ``high pressure, high temperature` zinc chromite methanol synthesis catalyst showed surprising activity at temperatures as low as 300{degree}C during the first successful stirred autoclave run with this catalyst. No C{sub 2{sup {plus}}} alcohols were detected, but significant levels of C{sub 2}-C{sub 4} olefins and dimethyl ether (DME) were produced. The presence of olefins suggests that higher alcohols might have formed and subsequently dehydrated. The slurry liquid, decahydronaphthalene, showed no evidence of decomposition during 15 days of continuous operation. 2 figs., 1 tab.

  4. Purge gas recovery of ammonia synthesis plant by integrated configuration of catalytic hydrogen-permselective membrane reactor and solid oxide fuel cell as a novel technology

    NASA Astrophysics Data System (ADS)

    Siavashi, Fakhteh; Saidi, Majid; Rahimpour, Mohammad Reza

    2014-12-01

    The purge gas emission of ammonia synthesis plant which contains hazardous components is one of the major sources of environmental pollution. Using integrated configuration of catalytic hydrogen-permselective membrane reactor and solid oxide fuel cell (SOFC) system is a new approach which has a great impact to reduce the pollutant emission. By application of this method, not only emission of ammonia and methane in the atmosphere is prevented, hydrogen is produced through the methane steam reforming and ammonia decomposition reactions that take place simultaneously in a catalytic membrane reactor. The pure generated hydrogen by recovery of the purge gas in the Pd-Ag membrane reactor is used as a feed of SOFC. Since water is the only byproduct of the electrochemical reaction in the SOFC, it is recycled to the reactor for providing the required water of the reforming reaction. Performance investigation of the reactor represents that the rate of hydrogen permeation increases with enhancing the reactor temperature and pressure. Also modeling results indicate that the SOFC performance improves with increasing the temperature and fuel utilization ratio. The generated power by recovery of the purging gas stream of ammonia synthesis plant in the Razi petrochemical complex is about 8 MW.

  5. Bench-scale demonstration of biological production of ethanol from coal synthesis gas. Quarterly report, January 1, 1994--March 31, 1994

    SciTech Connect

    Not Available

    1994-06-01

    This report presents results from the solvent selection, fermentation, and product recovery studies performed thus far in the development of a bench scale unit for the production of ethanol from coal-derived synthesis gas. Several additional solvents have been compared for their ability to extract ethanol from aqueous solutions of ethanol in water and fermentation permeate. The solvent 2,6-dimethyl-4-heptanol still appears to be the solvent of choice. Liquid-liquid equilibrium data have been collected for ethanol and 2,6-dimethyl-4-heptanol.

  6. Synthesis and evaluation of novel biochar-based and metal oxide-based catalysts for removal of model tar (toluene), ammonia, and hydrogen sulfide from simulated producer gas

    NASA Astrophysics Data System (ADS)

    Bhandari, Pushpak

    Gasification is a thermochemical conversion process in which carbonaceous feedstock is gasified in a controlled atmosphere to generate producer gas. The producer gas is used for production of heat, power, fuels and chemicals. Various contaminants such as tars, NH3, and H2S in producer gas possess many problems due to their corrosive nature and their ability to clog and deactivate catalysts. In this study, several catalysts were synthesized, characterized, and tested for removal of three contaminants (toluene (model tar), NH3, and H2S) from the biomass-generated producer gas. Biochar, a catalyst, was generated from gasification of switchgrass. Activated carbon and acidic surface activated carbon were synthesized using ultrasonication method from biochar. Acidic surface was synthesized by coating activated carbon with dilute acid. Mixed metal oxide catalysts were synthesized from hydrotalcite precursors using novel synthesis technique using microwave and ultrasonication. Surface area of activated carbon (˜900 m2/g) was significantly higher than that of its precursor biochar (˜60 m2/g). Surface area of metal oxide catalyst was approximately 180 m2/g after calcination. Biochar, activated carbon, and acidic surface activated carbon showed toluene removal efficiencies of approximately 78, 88, and 88 %, respectively, when the catalysts were tested individually with toluene in the presence of producer gas at 800 °C. The toluene removal efficiencies increased to 86, 91, and 97 % using biochar, activated carbon and acidic surface activated carbon, respectively in the presence of NH3 and H2S in the producer gas. Increase in toluene removal efficiencies in presence of NH3 and H2S indicates that NH3 and H 2S play a role in toluene reforming reactions during simultaneous removal of contaminants. Toluene removal efficiency for mixed metal oxide was approximately 83%. Ammonia adsorption capacities were 0.008 g NH3/g catalyst for biochar and 0.03g NH3/g catalyst for activated

  7. Equipment Design and Cost Estimation for Small Modular Biomass Systems, Synthesis Gas Cleanup, and Oxygen Separation Equipment; Task 1: Cost Estimates of Small Modular Systems

    SciTech Connect

    Nexant Inc.

    2006-05-01

    This deliverable is the Final Report for Task 1, Cost Estimates of Small Modular Systems, as part of NREL Award ACO-5-44027, ''Equipment Design and Cost Estimation for Small Modular Biomass Systems, Synthesis Gas Cleanup and Oxygen Separation Equipment''. Subtask 1.1 looked into processes and technologies that have been commercially built at both large and small scales, with three technologies, Fluidized Catalytic Cracking (FCC) of refinery gas oil, Steam Methane Reforming (SMR) of Natural Gas, and Natural Gas Liquids (NGL) Expanders, chosen for further investigation. These technologies were chosen due to their applicability relative to other technologies being considered by NREL for future commercial applications, such as indirect gasification and fluidized bed tar cracking. Research in this subject is driven by an interest in the impact that scaling has on the cost and major process unit designs for commercial technologies. Conclusions from the evaluations performed could be applied to other technologies being considered for modular or skid-mounted applications.

  8. Bench-scale demonstration of biological production of ethanol from coal synthesis gas. Quarterly report, September 24, 1992--December 31, 1992

    SciTech Connect

    Not Available

    1992-12-31

    Culture isolation and selection studies are being performed in order to select the best biological system for bench-scale studies in producing ethanol from syngas components. Three isolates have been found which produce more than 2 g/L ethanol from CO and C0{sub 2}/H{sub 2} in batch culture. These low concentrations are actually quite promising since Clostridium ljungdahlii, strain PETC, performs well in continuous culture but produces only small concentrations of ethanol in batch culture after several weeks of incubation. Two of the isolates have been utilized in the CSTR, where 90 percent CO conversions have been noted, while producing up to 2 g/L ethanol, in preliminary studies. CSTR studies will continue until steady state is reached. An anaerobic bacterium has been isolated from natural sources that converts the components of synthesis gas (CO, H{sub 2},C0{sub 2}) into ethanol. This organism, the only one known at that time to produce ethanol from synthesis gas, has been identified as a new clostridial strain and has been named Clostridium ljungdahlii, strain PETC.

  9. Comparative investigation on chemical looping combustion of coal-derived synthesis gas containing H2S over supported NiO oxygen carriers

    SciTech Connect

    Ksepko, E.; Siriwardane, R.; Tian, H.; Simonyi, T.; Sciazko, M.

    2010-01-01

    Chemical looping combustion (CLC) of simulated coal-derived synthesis gas was conducted with NiO oxygen carriers supported on SiO2, ZrO2, TiO2, and sepiolite. The effect of H2S on the performance of these samples for the CLC process was also evaluated. Five-cycle thermogravimetric analysis (TGA) tests at 800 C indicated that all oxygen carriers had a stable performance at 800 C, except NiO/SiO2. Full reduction/oxidation reactions of the oxygen carrier were obtained during the five-cycle test. It was found that support had a significant effect on reaction performance of NiO both in reduction and oxidation rates. The reduction reaction was significantly faster than the oxidation reaction for all oxygen carriers, while the oxidation reaction is fairly slow due to oxygen diffusion on NiO layers. The reaction profile was greatly affected by the presence of H2S, but there was no effect on the capacity due to the presence of H2S in synthesis gas. The presence of H2S decreased reduction reaction rates significantly, but oxidation rates of reduced samples increased. X-ray diffraction (XRD) data of the oxidized samples after a five-cycle test showed stable crystalline phases without any formation of sulfides or sulfites/sulfates. Increase in reaction temperature to 900 C had a positive effect on the performance.

  10. Effect of hydrogen sulfide on chemical looping combustion of coal-derived synthesis gas over bentonite-supported metal-oxide oxygen carriers

    SciTech Connect

    Tian, H.J.; Simonyi, T.; Poston, J.; Siriwardane, R.

    2009-09-15

    The effect of hydrogen sulfide (H{sub 2}S) on the chemical looping combustion of coal-derived synthesis gas with bentonite-supported metal oxides - such as iron oxide, nickel oxide, manganese oxide, and copper oxide - was investigated by thermogravimetric analysis, mass spectrometry, and X-ray photoelectron spectroscopy (XPS). During the reaction with synthesis gas containing H{sub 2}S, metal-oxide oxygen carriers were first reduced by carbon monoxide and hydrogen, and then interacted with H{sub 2}S to form metal sulfide, which resulted in a weight gain during the reduction/sulfidation step. The reduced/sulfurized compounds could be regenerated to form sulfur dioxide and oxides during the oxidation reaction with air. The reduction/oxidation capacities of iron oxide and nickel oxide were not affected by the presence of H{sub 2}S, but both manganese oxide and copper oxide showed decreased reduction/oxidation capacities. However, the rates of reduction and oxidation decreased in the presence of H{sub 2}S for all four metal oxides.

  11. Effect of hydrogen sulfide on chemical looping of coal-derived synthesis gas over bentonite-supported metal---oxide oxygen carriers

    SciTech Connect

    Tian, H.; Simonyi, T.; Poston, J.; Siriwardane, R.

    2009-01-01

    The effect of hydrogen sulfide (H2S) on the chemical looping combustion of coal-derived synthesis gas with bentonite-supported metal oxidesssuch as iron oxide, nickel oxide, manganese oxide, and copper oxideswas investigated by thermogravimetric analysis, mass spectrometry, and X-ray photoelectron spectroscopy (XPS). During the reaction with synthesis gas containing H2S, metal-oxide oxygen carriers were first reduced by carbon monoxide and hydrogen, and then interacted with H2S to form metal sulfide, which resulted in a weight gain during the reduction/sulfidation step. The reduced/sulfurized compounds could be regenerated to form sulfur dioxide and oxides during the oxidation reaction with air. The reduction/oxidation capacities of iron oxide and nickel oxide were not affected by the presence of H2S, but both manganese oxide and copper oxide showed decreased reduction/oxidation capacities. However, the rates of reduction and oxidation decreased in the presence of H2S for all four metal oxides.

  12. Sonochemical-driven ultrafast facile synthesis of SnO2 nanoparticles: Growth mechanism structural electrical and hydrogen gas sensing properties.

    PubMed

    Ullah, Hafeez; Khan, Ibrahim; Yamani, Zain H; Qurashi, Ahsanulhaq

    2017-01-01

    Synthesis of SnO2 nanoparticles have been successfully accomplished moderately at lower temperature by facile, rapid, efficient and mild ultrasonic irradiation method. The as-grown SnO2 nanoparticles are investigated by various characterization techniques in terms of structural, optical, electrical and gas sensing properties. XRD investigation has shown that the SnO2 nanoparticles materials exhibit single rutile crystal phase with high crystallinity. FESEM studies showed uniform and monodisperse morphology of SnO2 nanoparticles. The chemical composition of SnO2 was systematically studied by EDX measurements. Additional confirmation of three Raman shifts (432, 630, 772cm(-1)) indicated the characteristic properties of the rutile phase of the as-grown SnO2 nanoparticles. The optical properties of SnO2 nanoparticles were examined by DRS, and the electronic band gap of SnO2 nanoparticles were around 3.6eV. Electrical properties of the SnO2 nanoparticles measured at various temperatures have shown the semiconducting properties. Surface area and pore size of synthesized nanoparticles were analyzed from BET. It has been revealed that SnO2 nanoparticles have surface area is 47.8574m(2)/g and the pore size is 10.5nm. Moreover, hydrogen gas sensor made of SnO2 nanoparticles showed good sensitivity and faster response for the hydrogen gas. This method is template-less and surfactant-free which circumvents rigorous reaction work-up for the former removal, reaction temperature and reaction time compared to hydrothermal synthesis and pertinent to many other oxide materials.

  13. Advanced bioreactor concepts for gaseous substrates: Conversion of synthesis gas to liquid fuels and removal of SO{sub x} and NO{sub x} from coal combustion gases. CRADA final report

    SciTech Connect

    Kaufman, E.N.; Selvaraj, P.T.

    1997-10-01

    The purpose of the proposed research program was the development and demonstration of a new generation of gaseous substrate-based bioreactors for the production of liquid fuels from coal synthesis gas and the removal of NO{sub x} and SO{sub x} species from coal combustion flue gas. This study addressed the further investigation of optimal bacterial strains, growth media and kinetics for the biocatalytic conversion of coal synthesis gas to liquid fuel such as ethanol and the reduction of gaseous flue gas constituents. The primary emphasis was on the development of advanced bioreactor systems coupled with innovative biocatalytic systems that will provide increased productivity under controlled conditions. It was hoped that this would result in bioprocessing options that have both technical and economic feasibility, thus, ensuring early industrial use. Predictive mathematical models were formulated to accommodate hydrodynamics, mass transport, and conversion kinetics, and provide the data base for design and scale-up. The program was separated into four tasks: (1) Optimization of Biocatalytic Kinetics; (2) Development of Well-mixed and Columnar Reactors; (3) Development of Predictive Mathematical Models; and (4) Industrial Demonstration. Research activities addressing both synthesis gas conversion and flue gas removal were conducted in parallel by BRI and ORNL respectively.

  14. Ni(NiO)/single-walled carbon nanotubes composite: Synthesis of electro-deposition, gas sensing property for NO gas and density functional theory calculation

    SciTech Connect

    Li, Li; Zhang, Guo; Chen, Lei; Bi, Hong-Mei; Shi, Ke-Ying

    2013-02-15

    Graphical abstract: The Ni(NiO)/semiconducting single-walled carbon nanotubes composite collected from the cathode after electro-deposition shows a high sensitivity to low-concentration NO gas at room temperature (18 °C). Display Omitted Highlights: ► Ni(NiO) nanoparticles were deposited on semiconducting SWCNTs by electro-deposition. ► Ni(NiO)/semiconducting SWCNTs film shows a high sensitivity to NO gas at 18 °C. ►Theoretical calculation reveals electron transfer from SWCNTs to NO via Ni. -- Abstract: Single-walled carbon nanotubes which contains metallic SWCNTs (m-SWCNTs) and semiconducting SWCNTs (s-SWCNTs) have been obtained under electric arc discharge. Their separation can be effectively achieved by the electro-deposition method. The Ni(NiO)/s-SWCNTs composite was found on cathode where Ni was partially oxidized to NiO at ambient condition with Ni(NiO) nanoparticles deposited uniformly on the bundles of SWCNTs. These results were confirmed by Raman spectra, transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV–vis–NIR and TG characterizations. Furthermore, investigation of the gas sensing property of Ni(NiO)/s-SWCNTs composite film to NO gas at 18 °C demonstrated the sensitivity was approximately 5% at the concentration of 97 ppb. Moreover, density functional theory (DFT) calculations were performed to explore the sensing mechanism which suggested the adsorption of NO molecules onto the composite through N–Ni interaction as well as the proposition of electron transfer mechanisms from SWCNTs to NO via the Ni medium.

  15. SDS-assisted hydrothermal synthesis of NiO flake-flower architectures with enhanced gas-sensing properties

    NASA Astrophysics Data System (ADS)

    Miao, Ruiyang; Zeng, Wen; Gao, Qi

    2016-10-01

    A facile hydrothermal route was developed for the preparation of well-aligned hierarchical flower-like NiO nanostructure with the assistance of SDS that served as a structure-directing agent as well as a capping agent in the process of aggregation and assembly. Notably, the NiO sensors exhibit enhanced gas-sensing performance towards ethanol, which could be explained in association with the ultrathin nanosheets that are close to Debye length (LD) scale and thus get the majority carriers fully depleted due to the ionization of adsorbed oxygen, abundant effective gas diffusion paths as well as high surface-to-volume ratio to promote sufficient contact and reaction between the NiO sample and ethanol molecules, and numerous miniature reaction rooms assembled with nanosheets to make the test gas molecules stay long enough for completed gas-sensing reactions. Besides, a novel growth mechanism with the passage of reaction time was also proposed in detail.

  16. Novel approaches to the production of higher alcohols from synthesis gas. Quarterly technical progress report No. 9, October 1, 1992--December 31, 1992

    SciTech Connect

    Not Available

    1993-04-28

    Several possible high-temperature reactor oils have been identified and are being evaluated. One candidate, Drakeol{reg_sign} 34 mineral oil, appeared to decompose rapidly during testing at 425{degree}C in the stirred autoclave. However, a thermal stability test in laboratory glassware showed that Drakeol{reg_sign} 34 was stable at about 360{degree}C, suggesting that the decomposition observed in the autoclave was not caused simply by high temperature. Another oil, Ethylflo{reg_sign} 180, also showed no signs of decomposition during thermal stability testing in the laboratory, also at a temperature of about 360{degree}C. The first of three methanol synthesis verification runs was conducted in the stirred autoclave, using the commercial BASF Cu/ZnO catalyst. Gas chromatograph failures and apparent catalyst deactivation prevented collection of any meaningful data during the run.

  17. Improving the purity of GaN grown by the ammonothermal method with in-autoclave gas-phase acidic mineralizer synthesis

    NASA Astrophysics Data System (ADS)

    Tomida, D.; Chichibu, S. F.; Kagamitani, Y.; Bao, Q.; Hazu, K.; Simura, R.; Sugiyama, K.; Yokoyama, C.; Ishiguro, T.; Fukuda, T.

    2012-06-01

    In-autoclave synthesis of a gas-phase acidic mineralizer was investigated for high-purity GaN growth by the ammonothermal (AT) method. To reduce oxygen contamination of GaN from highly hygroscopic NH4Cl powder, purified NH3 and HCl gases were introduced sequentially fed into a Pt-lined autoclave to synthesize NH4Cl within the autoclave. The autoclave was pre-charged with GaN seed wafers and polycrystalline precursors, and carefully dehydrated under dynamic vacuum. Because of the decrease in oxygen concentration, the lattice parameter approached the intrinsic value. The Ga-polar layers exhibit a near-band-edge emission peak at room temperature.

  18. Low cost hydrogen/novel membrane technology for hydrogen separation from synthesis gas, Phase 1. Quarterly technical progress report for the period ending March 31, 1986

    SciTech Connect

    Not Available

    1986-12-31

    The goal of this program is to develop polymer membranes useful in the preparation of hydrogen from coal-derived synthesis gas. During this quarter the first experiment were aimed at developing high performance composite membranes for the separation of hydrogen from nitrogen and carbon monoxide. Three polymers have been selected as materials for these membranes: polyetherimide cellulose acetate and ethylcellulose. This quarter the investigators worked on polyetherimide and cellulose acetate membranes. The overall structure of these membranes is shown schematically in Figure 1. As shown, a microporous support membrane is first coated with a high flux intermediate layer then with an ultrathin permselective layer and finally, if necessary, a thin protective high flux layer. 1 fig., 4 tabs.

  19. One-step synthesis of MoO3 and MoO3-x nanostructures by condensation in gas: effect of the carrier gas.

    PubMed

    Diaz-Droguett, D E; Fuenzalida, V M

    2010-10-01

    MoO3 and MoO3-x nanostructures were grown in a simple one-step process by direct evaporation of MoO3 pellets from a tungsten resistive source in presence of helium or hydrogen at pressures from 100 to 1200 Pa. This method uses no templates, catalysts or oxidizing agents. It leads to one dimensional (1-D) crystalline nanostructures mixed with amorphous material in variable ratios. Amorphous structures grew preferentially when hydrogen was used as carrier gas while crystalline material predominated when helium was used. In fact, only crystalline structures were found when the evaporation was carried out under a helium pressure of 600 Pa with source temperatures between 763 and 910 degrees C. Hydrated MoO3 phases with different water concentrations were preferentially formed using hydrogen. X-ray photoelectron spectroscopy detected only molybdenum in its +6 oxidation state in the samples grown under helium, exhibiting the same chemical composition of the source material. Molybdenum in its +6 as well as its +5 oxidation states was detected in the samples obtained under hydrogen at 600 Pa. Hydroxyl groups were identified in samples grown using both gases. The effect of the helium pressure on the growth kinetics and crystallinity of the samples is discussed according to the kinetics conditions (supersaturation, evaporation, cooling and convection rates) driving to the formation of nanostructures in the inert-gas condensation. Finally, the effect of hydrogen on the growth of MoO3 is discussed.

  20. Novel approaches to the production of higher alcohols from synthesis gas. Quarterly technical progress report No. 17, October 1, 1994-- December 31, 1994

    SciTech Connect

    1996-07-05

    A series of experiments in which the stirrer speed was varied during a methanol synthesis run with BASF S3-86 catalyst showed that mass transfer limitations were present at 750 psig reactor pressure and at space velocities of 5000 and 10000 sl/kg(cat.)-hr.. There was no effect of stirrer speed on reaction rate at 2500 psig reactor pressure and 16500 sl/kg(cat.)-hr. space velocity. However, this was probably due to a close approach to equilibrium rather than to the lack of a mass transfer effect. The most plausible explanation for the presence of a mass transfer influence is the position of the gas feed dip tube relative to the agitator impeller. A second set of stirrer speed experiments using the same catalyst showed that feeding into the reactor headspace produced much lower reaction rates, compared with gas feed through a dip tube. The headspace feed also showed a strong dependence on stirrer speed, consistent with the dip tube feed results. In a ``blank` run at 375{degree}C with decahydronaphthalene, about 110 mL of the initial charge of 150 mL remained in the reactor after 73 hours of operation at 375{degree}C and 850 psig of hydrogen. The rate of hydrocarbon evolution was low throughout the run. Decalin is the most stable liquid identified to date. Three stirred autoclave runs with a commercial, high-pressure methanol synthesis catalyst (zinc chromite) slurried in decahydronaphthalene ended son after the initial catalyst reduction due to failures of the liquid return pump in the overhead system. However, the catalyst appeared to be reduced and the liquid appeared to be stable. 4 figs., 1 tab.

  1. Sol-gel synthesis of mesoporous CaCu{sub 3}Ti{sub 4}O{sub 12} thin films and their gas sensing response

    SciTech Connect

    Parra, R.; Savu, R.; Varela, J.A.; Bueno, P.R.

    2010-06-15

    A new sol-gel synthesis procedure of stable calcium copper titanate (CaCu{sub 3}Ti{sub 4}O{sub 12}-CCTO) precursor sols for the fabrication of porous films was developed. The composition of the sol was selected in order to avoid the precipitation of undesired phases; ethanol was used as solvent, acetic acid as modifier and poly(ethyleneglycol) as a linker agent. Films deposited by spin-coating onto oxidized silicon substrates were annealed at 700 {sup o}C. The main phase present in the samples, as detected by X-ray diffraction and Raman spectroscopy, was CaCu{sub 3}Ti{sub 4}O{sub 12}. Scanning electron microscopy analysis showed that mesoporous structures, with thicknesses between 200 and 400 nm, were developed as a result of the processing conditions. The films were tested regarding their sensibility towards oxygen and nitrogen at atmospheric pressure using working temperatures from 200 to 290 {sup o}C. The samples exhibited n-type conductivity, high sensitivity and short response times. These characteristics indicate that CCTO mesoporous structures obtained by sol-gel are suitable for application in gas sensing. - Graphical abstract: A sol-gel synthesis procedure toward stable CaCu{sub 3}Ti{sub 4}O{sub 12}-precursor sols avoiding the precipitation of undesired compounds is proposed. Films deposited by spin-coating onto oxidized silicon substrates were annealed at 700 {sup o}C. The thickness varied between 200 and 400 nm depending on sol composition. The films, tested as gas sensors for O{sub 2}, showed n-type conductivity, good sensitivity and short response times.

  2. Gas-Phase Synthesis of Boronylallene (H2CCCH(BO)) under Single Collision Conditions: A Crossed Molecular Beams and Computational Study.

    PubMed

    Maity, Surajit; Parker, Dorian S N; Kaiser, Ralf I; Ganoe, Brad; Fau, Stefan; Perera, Ajith; Bartlett, Rodney J

    2014-05-15

    The gas phase reaction between the boron monoxide radical ((11)BO; X(2)Σ(+)) and allene (H2CCCH2; X(1)A1) was investigated experimentally under single collision conditions using the crossed molecular beam technique and theoretically exploiting ab initio electronic structure and statistical (RRKM) calculations. The reaction was found to follow indirect (complex forming) scattering dynamics and proceeded via the formation of a van der Waals complex ((11)BOC3H4). This complex isomerized via addition of the boron monoxide radical ((11)BO; X(2)Σ(+)) with the radical center located at the boron atom to the terminal carbon atom of the allene molecule forming a H2CCCH2(11)BO intermediate on the doublet surface. The chemically activated H2CCCH2(11)BO intermediate underwent unimolecular decomposition via atomic hydrogen elimination from the terminal carbon atom holding the boronyl group through a tight exit transition state to synthesize the boronylallene product (H2CCCH(11)BO) in a slightly exoergic reaction (55 ± 11 kJ mol(-1)). Statistical (RRKM) calculations suggest that minor reaction channels lead to the products 3-propynyloxoborane (CH2((11)BO)CCH) and 1-propynyloxoborane (CH3CC(11)BO) with fractions of 1.5% and 0.2%, respectively. The title reaction was also compared with the cyano (CN; X(2)Σ(+))-allene and boronyl-methylacetylene reactions to probe similarities, but also differences of these isoelectronic systems. Our investigation presents a novel gas phase synthesis and characterization of a hitherto elusive organyloxoborane (RBO) monomer-boronylallene-which is inherently tricky to isolate in the condensed phase except in matrix studies; our work further demonstrates that the crossed molecular beams approach presents a useful tool in investigating the chemistry and synthesis of highly reactive organyloxoboranes.

  3. Production of carbon nanotubes: Chemical vapor deposition synthesis from liquefied petroleum gas over Fe-Co-Mo tri-metallic catalyst supported on MgO

    NASA Astrophysics Data System (ADS)

    Setyopratomo, P.; Wulan, Praswasti P. D. K.; Sudibandriyo, M.

    2016-06-01

    Carbon nanotubes were produced by chemical vapor deposition method to meet the specifications for hydrogen storage. So far, the various catalyst had been studied outlining their activities, performances, and efficiencies. In this work, tri-metallic catalyst consist of Fe-Co-Mo supported on MgO was used. The catalyst was prepared by wet-impregnation method. Liquefied Petroleum Gas (LPG) was used as carbon source. The synthesis was conducted in atmospheric fixed bed reactor at reaction temperature range 750 - 850 °C for 30 minutes. The impregnation method applied in this study successfully deposed metal component on the MgO support surface. It found that the deposited metal components might partially replace Mg(OH)2 or MgO molecules in their crystal lattice. Compare to the original MgO powder; it was significant increases in pore volume and surface area has occurred during catalyst preparation stages. The size of obtained carbon nanotubes is ranging from about 10.83 nm OD/4.09 nm ID up to 21.84 nm OD/6.51 nm ID, which means that multiwall carbon nanotubes were formed during the synthesis. Yield as much as 2.35 g.CNT/g.catalyst was obtained during 30 minutes synthesis and correspond to carbon nanotubes growth rate of 0.2 μm/min. The BET surface area of the obtained carbon nanotubes is 181.13 m2/g and around 50 % of which is contributed by mesopores. Micropore with half pore width less than 1 nm contribute about 10% volume of total micro and mesopores volume of the carbon nanotubes. The existence of these micropores is very important to increase the hydrogen storage capacity of the carbon nanotubes.

  4. Novel approaches to the production of higher alcohols from synthesis gas. Quarterly technical progress report No. 11, April 1, 1993--June 30, 1993

    SciTech Connect

    Not Available

    1993-11-22

    This document reports work during this quarter on the project to produce higher alcohols from synthesis gas. A set of four methanol synthesis runs was conducted. Significant catalyst deactivation was experienced, and essentially all of the oil was lost from the reactor over the course of two weeks of operation. Three screening runs of potential high temperature oil were also conducted. However, essentially no oil remained in the reactor after completion of each run. A 1%Rh/1.3%Re/Al{sub 2}O{sub 3} catalyst was prepared from Re and Rh carbonyls with the objective of obtaining intimate contact between Rh and Re atoms. The catalytic activity of this catalyst was explored. Mo was deposited on the catalyst from both molybdenum hexacarbonyl [Mo(CO){sub 6}] and (NH{sub 4}){sub 6}Mo{sub 7}O{sub 24}{center_dot}4H{sub 2}O. The catalytic activity of the molybdenum promoted catalysts was found to be the highest achieved to date under this contract.

  5. Novel approaches to the production of higher alcohols from synthesis gas. Quarterly progress report, April 1, 1994--June 30, 1994

    SciTech Connect

    Roberts, G.W.

    1996-05-01

    Under Task 2, four sets of methanol synthesis run were conducted with BASF S3-86 ``low pressure``, Cu/ZnO methanol synthesis catalyst. The objectives were: (1) to reproduce the data obtained with this catalyst by researchers at Air Products and Chemicals, Inc., and: (2) to determine whether the previously-observed problem of catalyst poisoning by metal carbonyls had been eliminated. The catalyst poisoning problem appears to be resolved, although there is a need for additional data on the capacity of activated carbon for iron and nickel carbonyl absorption. However, under apparently comparable conditions, the activity of the BASF S3-86 catalyst in the present experiments was lower than the activity measured at Air Products. The difference tentatively has been attributed to differences in the catalyst activation procedure. Problems with reliability of the experimental equipment were experienced: these problems limited the quality and quantity of the experimental data.

  6. Simultaneous amination of TiO2 nanoparticles in the gas phase synthesis for bio-medical applications

    NASA Astrophysics Data System (ADS)

    Lee, Kyoung-No; Kim, Yangeon; Lee, Chang-Woo; Lee, Jai-Sung

    2011-10-01

    A simultaneous synthesis and surface amination method to effectively modify the surface of inorganic nanoparticles is discussed in this study. As a target material system and surface functional group, TiO2 nanoparticles and amine were selected. APTES (3-aminopropyltriethoxysilane), the source of amine group, was mixed with TTIP (titanium tetraisopropoxide) and used for the synthesis of aminated TiO2 nanoparticles. XRD (X-ray diffractometry) results showed TiO2 nanoparticles of pure anatase phase, 15 nm in crystallite size, were successfully synthesized at 700°C and 50 mbar. Fourier transformation infrared (FT-IR) spectroscopy measurement and confocal microscopy study using fluoresceine isothiocyanate (FITC) confirmed that amine groups were successfully deposited and activated on the surface of TiO2 nanoparticles.

  7. Analysis of Mammalian Cell Proliferation and Macromolecule Synthesis Using Deuterated Water and Gas Chromatography-Mass Spectrometry

    PubMed Central

    Foletta, Victoria C.; Palmieri, Michelle; Kloehn, Joachim; Mason, Shaun; Previs, Stephen F.; McConville, Malcolm J.; Sieber, Oliver M.; Bruce, Clinton R.; Kowalski, Greg M.

    2016-01-01

    Deuterated water (2H2O), a stable isotopic tracer, provides a convenient and reliable way to label multiple cellular biomass components (macromolecules), thus permitting the calculation of their synthesis rates. Here, we have combined 2H2O labelling, GC-MS analysis and a novel cell fractionation method to extract multiple biomass components (DNA, protein and lipids) from the one biological sample, thus permitting the simultaneous measurement of DNA (cell proliferation), protein and lipid synthesis rates. We have used this approach to characterize the turnover rates and metabolism of a panel of mammalian cells in vitro (muscle C2C12 and colon cancer cell lines). Our data show that in actively-proliferating cells, biomass synthesis rates are strongly linked to the rate of cell division. Furthermore, in both proliferating and non-proliferating cells, it is the lipid pool that undergoes the most rapid turnover when compared to DNA and protein. Finally, our data in human colon cancer cell lines reveal a marked heterogeneity in the reliance on the de novo lipogenic pathway, with the cells being dependent on both ‘self-made’ and exogenously-derived fatty acid. PMID:27754354

  8. Synthesis and room-temperature NO2 gas sensing properties of a WO3 nanowires/porous silicon hybrid structure

    NASA Astrophysics Data System (ADS)

    Zeng, Peng; Zhang, Ping; Hu, Ming; Ma, Shuang-Yun; Yan, Wen-Jun

    2014-05-01

    We report on the fabrication and performance of a room-temperature NO2 gas sensor based on a WO3 nanowires/porous silicon hybrid structure. The W18O49 nanowires are synthesized directly from a sputtered tungsten film on a porous silicon (PS) layer under heating in an argon atmosphere. After a carefully controlled annealing treatment, WO3 nanowires are obtained on the PS layer without losing the morphology. The morphology, phase structure, and crystallinity of the nanowires are investigated by using field emission scanning electron microscopy (FESEM), X-ray diffractometer (XRD), and high-resolution transmission electron microscopy (HRTEM). Comparative gas sensing results indicate that the sensor based on the WO3 nanowires exhibits a much higher sensitivity than that based on the PS and pure WO3 nanowires in detecting NO2 gas at room temperature. The mechanism of the WO3 nanowires/PS hybrid structure in the NO2 sensing is explained in detail.

  9. Hierarchically solvothermal synthesis of WO3-based nanocomposite: Nature-inspired structure and enhanced gas-sensing property

    NASA Astrophysics Data System (ADS)

    Long, Huiwu; Zeng, Wen; Li, Tianming

    2017-04-01

    Composed of the heart, cardiac valves and blood vessels, the blood circulation system can manage the aggregation and the movement of the blood regularly and efficiently. Due to the analogical fluidity of the charge carrier and the blood, such system may act as the inspiration to design the advanced gas-sensing material. As a proof-of-concept, firstly, the porous WO3 monomer was synthesized and recombined with the one-dimensional NiO monomer through the P-N junction to construct a similar structure. Subsequently, a series of gas-sensing tests towards the ethanol were measured. The obtained result indicates this nature-inspired nanocomposite indeed shows an enhanced gas-sensing property towards the ethanol, testifying the rationality of our design.

  10. DEVELOPMENT OF NOVEL CERAMIC NANOFILM-FIBER INTEGRATED OPTICAL SENSORS FOR RAPID DETECTION OF COAL DERIVED SYNTHESIS GAS

    SciTech Connect

    Junhang Dong; Hai Xiao; Xiling Tang; Hongmin Jiang; Kurtis Remmel; Amardeep Kaur

    2012-09-30

    The overall goal of this project is to conduct fundamental studies on advanced ceramic materials and fiber optic devices for developing new types of high temperature (>500{degree}C) fiber optic chemical sensors (FOCS) for monitoring fossil (mainly coal) and biomass derived gases in power plants. The primary technical objective is to investigate and demonstrate the nanocrystalline doped-ceramic thin film enabled FOCS that possess desired stability, sensitivity and selectivity for in-situ, rapid gas detection in the syngas streams from gasification and combustion flue gases. This report summarizes research works of two integrated parts: (1) development of metal oxide solid thin films as sensing materials for detection and measurement of important gas components relevant to the coal- and biomass-derived syngas and combustion gas streams at high temperatures; and (2) development of fiber optic devices that are potentially useful for constructing FOCS in combination with the solid oxide thin films identified in this program.

  11. Bench-scale demonstration of biological production of ethanol from coal synthesis gas. Quarterly report, October 1, 1993--December 31, 1993

    SciTech Connect

    Not Available

    1993-12-31

    This project describes a new approach to coal liquefaction, the biological conversion of coal synthesis gas into a liquid fuel, ethanol. A new bacterium, Clostridium Ijungdahlii, strain PETC, has been discovered and developed for this conversion, which also produces acetate as a by-product. Based upon the results of an exhaustive literature search and experimental data collected in the ERI laboratories, secondary and/or branched alcohols have been selected for ethanol extraction from the fermentation broth. 2,6 Methyl 4-heptanol has a measured distribution coefficient of 0.44 and a separation factor of 47. Methods to improve the results from extraction by removing water prior to distillation are under consideration. Several runs were performed in the two-stage CSTR system with Clostridium Ijungdahlii, strain PETC, with and without cell recycle between stages. Reduced gas flow rate, trypticase limitation and ammonia limitation as methods of maximizing ethanol production were the focus of the studies. With ammonia limitation, the ethanol:acetate product ratio reached 4.0.

  12. Gas cleaning system and method

    DOEpatents

    Newby, Richard Allen

    2006-06-06

    A gas cleaning system for removing at least a portion of contaminants, such as halides, sulfur, particulates, mercury, and others, from a synthesis gas (syngas). The gas cleaning system may include one or more filter vessels coupled in series for removing halides, particulates, and sulfur from the syngas. The gas cleaning system may be operated by receiving gas at a first temperature and pressure and dropping the temperature of the syngas as the gas flows through the system. The gas cleaning system may be used for an application requiring clean syngas, such as, but not limited to, fuel cell power generation, IGCC power generation, and chemical synthesis.

  13. Surface-area-controlled synthesis of porous TiO2 thin films for gas-sensing applications.

    PubMed

    Park, Jae Young; Kim, Ho-Hyoung; Rana, Dolly; Jamwal, Deepika; Katoch, Akash

    2017-03-03

    Surface-area-controlled porous TiO2 thin films were prepared via a simple sol-gel chemical route, and their gas-sensing properties were thoroughly investigated in the presence of typical oxidizing NO2 gas. The surface area of TiO2 thin films was controlled by developing porous TiO2 networked by means of controlling the TiO2-to-TTIP (titanium isopropoxide, C12H28O4Ti) molar ratio, where TiO2 nanoparticles of size ∼20 nm were used. The sensor's response was found to depend on the surface area of the TiO2 thin films. The porous TiO2 thin-film sensor with greater surface area was more sensitive than those of TiO2 thin films with lesser surface area. The improved sensing ability was ascribed to the porous network formed within the thin films by TiO2 sol. Our results show that surface area is a key parameter for obtaining superior gas-sensing performance; this provides important guidelines for preparing and using porous thin films for gas-sensing applications.

  14. Synthesis of porous SnO2 nanocubes via selective leaching and enhanced gas-sensing properties

    NASA Astrophysics Data System (ADS)

    Li, Yining; Wei, Qi; Song, Peng; Wang, Qi

    2016-01-01

    Porous micro-/nanostructures are of great interest in many current and emerging areas of technology. In this paper, porous SnO2 nanocubes have been successfully fabricated via a selective leaching strategy using CoSn(OH)6 as precursor. The structure and morphology of as-prepared samples were investigated by several techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric and differential scanning calorimeter analysis (TG⿿DSC), transmission electron microscopy (TEM) and N2 adsorption⿿desorption analyses. On the basis of those characterizations, the mechanism for the formation of porous SnO2 nanocubes has been proposed. Owing to the well-defined and uniform porous structures, porous SnO2 nanocubes possessing more adsorbent amount of analytic gas and accelerate the transmission speed so as to enhance the gas-sensing properties. Gas sensing investigation showed that the sensor based on porous SnO2 nanocubes exhibited high response, short response⿿recovery times and good selectivity to ethanol gas.

  15. Surface-area-controlled synthesis of porous TiO2 thin films for gas-sensing applications

    NASA Astrophysics Data System (ADS)

    Park, Jae Young; Kim, Ho-hyoung; Rana, Dolly; Jamwal, Deepika; Katoch, Akash

    2017-03-01

    Surface-area-controlled porous TiO2 thin films were prepared via a simple sol–gel chemical route, and their gas-sensing properties were thoroughly investigated in the presence of typical oxidizing NO2 gas. The surface area of TiO2 thin films was controlled by developing porous TiO2 networked by means of controlling the TiO2-to-TTIP (titanium isopropoxide, C12H28O4Ti) molar ratio, where TiO2 nanoparticles of size ∼20 nm were used. The sensor’s response was found to depend on the surface area of the TiO2 thin films. The porous TiO2 thin-film sensor with greater surface area was more sensitive than those of TiO2 thin films with lesser surface area. The improved sensing ability was ascribed to the porous network formed within the thin films by TiO2 sol. Our results show that surface area is a key parameter for obtaining superior gas-sensing performance; this provides important guidelines for preparing and using porous thin films for gas-sensing applications.

  16. Synthesis, Structure, and Ethanol Gas Sensing Properties of In2O3 Nanorods Decorated with Bi2O3 Nanoparticles.

    PubMed

    Park, Sunghoon; Kim, Soohyun; Sun, Gun-Joo; Lee, Chongmu

    2015-04-22

    Bi2O3-decorated In2O3 nanorods were synthesized using a one-step process, and their structure, as well as the effects of decoration of In2O3 nanorods with Bi2O3 on the ethanol gas-sensing properties were examined. The multiple networked Bi2O3-decorated In2O3 nanorod sensor showed responses of 171-1774% at ethanol concentrations of 10-200 ppm at 200 °C. The responses of the Bi2O3-decorated In2O3 nanorod sensor were stronger than those of the pristine-In2O3 nanorod sensors by 1.5-4.9 times at the corresponding concentrations. The two sensors exhibited short response times and long recovery times. The optimal Bi concentration in the Bi2O3-decorated In2O3 nanorod sensor and the optimal operation temperature of the sensor were 20% and 200 °C, respectively. The Bi2O3-decorated In2O3 nanorod sensor showed selectivity for ethanol gas over other gases. The origin of the enhanced response, sensing speed, and selectivity for ethanol gas of the Bi2O3-decorated In2O3 nanorod sensor to ethanol gas is discussed.

  17. Shell's Middle Distillate Synthesis process

    SciTech Connect

    Voetter, H.; VanDerBurgt, M.J. B.V., The Hague )

    1988-01-01

    The basis of the Shell Middle Distillate Synthesis (SMDS) process is the classic Fischer-Tropsch synthesis. For the case of middle distillate production from natural gas the procedure has been developed to commercial maturity, making use of tailored line-up for synthesis gas production and of proprietary modern catalysts in synthesis. Development work over the last years has in particular lead to improvement of the economy of the process altogether via catalyst performance, reactor sizing and syngas manufacturing line-up.

  18. Synthesis of SnO2 nanoparticles using a solution plasma and their gas-sensing properties

    NASA Astrophysics Data System (ADS)

    Zhang, Jianbo; Hu, Xiulan; Shi, Junjun; Lu, Ping; Shen, Xiaodong; Xu, Peifeng; Saito, Nagahiro

    2016-01-01

    A simple solution plasma method was applied to the synthesis of SnO2 nanoparticles directly from tin(II) chloride solution, without adding any precipitant, stabilizer, or other agents at atmospheric pressure, because solution plasma provides a reaction field with a highly excited energy state. The results of X-ray power diffraction (XRD) analysis and transmission electron microscopy (TEM) verified that well-crystallized SnO2 nanoparticles in the size range of 2-5 nm were synthesized. SnO2 nanoparticles show satisfactory sensitivities to acetaldehyde and ethanol.

  19. The economical production of alcohol fuels from coal-derived synthesis gas. Quarterly technical progress report No. 4, July 1, 1992--September 30, 1992

    SciTech Connect

    Not Available

    1993-10-01

    A base case flow sheet for the production of higher alcohols from coal derived synthesis gas has been completed, including an economic analysis. The details of the flow sheet and economics are in Appendix 1. The pay back period for the capital investment for the plant has been calculated as a function of the market price of the product, and this figure is also shown as Figure I in Appendix 1. The estimated installed cost is almost $500 MM, and the estimated annual operating cost is $64 MM. At a price in the vicinity of $1.00/gal for the alcohol product, the pay back period for construction of the plant is four years. These values should be considered preliminary, since many of the capital costs were obtained from other paper studies sponsored by DOE and TVA and very few values could be found from actual plants which were built. This issue is currently being addressed. The most expensive capital costs were found to be the gasifier, the cryogenic air separation plant, the steam/power generation plant and the acid gas/sulfur removal processes taken as a whole. It is planned to focus attention on alternatives to the base case. The problem is that it is less expensive to make syngas from natural gas. Therefore, it is essential to reduce the cost of syngas from coal. This is where the energy park concept becomes important. In order for this process to be economical (at current market and political conditions) a method must be found to reduce the cost of syngas manufacture either by producing energy or by-products. Energy is produced in the base case, but the amount and method has not been optimized. The economic arguments for this concept are detailed in Appendix 2.

  20. The Application of Gas Dwell Time Control for Rapid Single Wall Carbon Nanotube Forest Synthesis to Acetylene Feedstock

    PubMed Central

    Matsumoto, Naoyuki; Oshima, Azusa; Sakurai, Shunsuke; Yamada, Takeo; Yumura, Motoo; Hata, Kenji; Futaba, Don N.

    2015-01-01

    One aspect of carbon nanotube (CNT) synthesis that remains an obstacle to realize industrial mass production is the growth efficiency. Many approaches have been reported to improve the efficiency, either by lengthening the catalyst lifetime or by increasing the growth rate. We investigated the applicability of dwell time and carbon flux control to optimize yield, growth rate, and catalyst lifetime of water-assisted chemical vapor deposition of single-walled carbon nanotube (SWCNT) forests using acetylene as a carbon feedstock. Our results show that although acetylene is a precursor to CNT synthesis and possesses a high reactivity, the SWCNT forest growth efficiency is highly sensitive to dwell time and carbon flux similar to ethylene. Through a systematic study spanning a wide range of dwell time and carbon flux levels, the relationship of the height, growth rate, and catalyst lifetime is found. Further, for the optimum conditions for 10 min growth, SWCNT forests with ~2500 μm height, ~350 μm/min initial growth rates and extended lifetimes could be achieved by increasing the dwell time to ~5 s, demonstrating the generality of dwell time control to highly reactive gases.

  1. Synthesis of TiN and (Ti, Al)N powders by mechanical alloying in nitrogen gas

    SciTech Connect

    Ogino, Y.; Yamasaki, T.; Miki, M.; Atsumi, N.; Yoshioka, K. )

    1993-04-15

    Mechanical alloying (MA) is a nonequilibrium alloying process with which various unstable or metastable materials, such as highly supersaturated solid solutions, amorphous alloys and intermetallic compounds, can be prepared. Although MA has been applied most extensively to alloying between solid elements, it is also an effective means for allying gaseous elements by solid-gas reactions. In particular, nitrogen can be alloyed up to very high concentrations with nitride-forming transition metals and their alloys by ball milling their powders in nitrogen gas. In the present study, the authors applied this new nitriding technique to the preparation of TiN and a solid solution nitride (Ti, Al)N, and examined the nitriding kinetics and thermal stabilities of the nitrides.

  2. Synthesis of fluorinated nano-silica and its application in wettability alteration near-wellbore region in gas condensate reservoirs

    NASA Astrophysics Data System (ADS)

    Mousavi, M. A.; Hassanajili, Sh.; Rahimpour, M. R.

    2013-05-01

    Fluorinated silica nanoparticles were prepared to alter rock wettability near-wellbore region in gas condensate reservoirs. Hence fluorinated silica nanoparticles with average diameter of about 80 nm were prepared and used to alter limestone core wettability from highly liquid-wet to intermediate gas-wet state. Water and n-decane contact angles for rock were measured before and after treatment. The contact angle measured 147° for water and 61° for n-decane on the core surface. The rock surface could not support the formation of any water or n-decane droplets before treatment. The functionalized fluorinated silica nanoparticles have been confirmed by the Csbnd F bond along with Sisbnd Osbnd Si bond as analyzed by FT-IR. The elemental composition of treated limestone core surface was determined using energy dispersive X-ray spectroscopy analyses. The final evaluation of the fluorinated nanosilica treatment in terms of its effectiveness was measured by core flood experimental tests.

  3. Synthesis of Aluminum-Aluminum Nitride Nanocomposites by Gas-Liquid Reactions I. Thermodynamic and Kinetic Considerations

    NASA Astrophysics Data System (ADS)

    Borgonovo, Cecilia; Makhlouf, Makhlouf M.

    2016-10-01

    In-situ fabrication of the reinforcing particles directly in the metal matrix is an answer to many of the challenges encountered in manufacturing metal matrix nanocomposite materials. In this method, the nanosized particles are formed directly within the melt by means of a chemical reaction between a specially designed metallic alloy and a reactive gas. The thermodynamic and kinetic characteristics of this chemical reaction dictate the particle size and distribution in the matrix alloy, as well as the nature of the particle/matrix interface, and consequently, they govern many of the material's mechanical and physical properties. This article focuses on aluminum-aluminum-nitride nanocomposite materials that are synthesized by injecting a nitrogen-bearing gas into a molten aluminum alloy. The thermodynamic and kinetic aspects of the process are modeled, and the detrimental role of oxygen is elucidated.

  4. Selective interfacial synthesis of metal-organic frameworks on a polybenzimidazole hollow fiber membrane for gas separation

    NASA Astrophysics Data System (ADS)

    Biswal, Bishnu P.; Bhaskar, Anand; Banerjee, Rahul; Kharul, Ulhas K.

    2015-04-01

    Metal-organic frameworks (MOFs) have gained immense attention as new age materials due to their tuneable properties and diverse applicability. However, efforts on developing promising materials for membrane based gas separation, and control over the crystal growth positions on polymeric hollow fiber membranes still remain key challenges. In this investigation, a new, convenient and scalable room temperature interfacial method for growing MOFs (ZIF-8 and CuBTC) on either the outer or inner side of a polybenzimidazole based hollow fiber (PBI-BuI-HF) membrane surface has been achieved in a controlled manner. This was made possible by the appropriate selection of an immiscible solvent pair and the synthetic conditions. The growth of MOFs on the PBI-BuI-HF membrane by the interfacial method was continuous and showed an appreciable gas separation performance, conveying promise for their applicability.Metal-organic frameworks (MOFs) have gained immense attention as new age materials due to their tuneable properties and diverse applicability. However, efforts on developing promising materials for membrane based gas separation, and control over the crystal growth positions on polymeric hollow fiber membranes still remain key challenges. In this investigation, a new, convenient and scalable room temperature interfacial method for growing MOFs (ZIF-8 and CuBTC) on either the outer or inner side of a polybenzimidazole based hollow fiber (PBI-BuI-HF) membrane surface has been achieved in a controlled manner. This was made possible by the appropriate selection of an immiscible solvent pair and the synthetic conditions. The growth of MOFs on the PBI-BuI-HF membrane by the interfacial method was continuous and showed an appreciable gas separation performance, conveying promise for their applicability. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr00299k

  5. Synthesis and enhanced NO2 gas sensing properties of ZnO nanorods/TiO2 nanoparticles heterojunction composites.

    PubMed

    Zou, C W; Wang, J; Xie, W

    2016-09-15

    ZnO nanorods/TiO2 nanoparticles composites were synthesized and the effects of TiO2 concentrations on the NO2 sensing properties were studied in detail. The as-prepared composites were characterized by XRD, SEM, TEM, PL, I-V and gas sensing measurements. The gas sensing results demonstrated that all the sensors based on ZnO/TiO2 nanocomposites exhibited much higher response than that of sensors based on pure ZnO nanorods. At the optimum operating temperature of 180°C, the response values of the sensors based on ZnO/TiO2 nanocomposites decorated with TiO2 concentrations of 0, 3, 5, 8 and 10wt% were 50, 140, 310, 350 and 258, respectively. The PL and I-V results indicated that the increased charge transfer between the ZnO nanorods mediated by TiO2 nanoparticles enhanced the conductivity of the ZnO/TiO2 nanocomposites. The gas sensing mechanism was also carefully analyzed. The attachment of TiO2 nanoparticles onto ZnO nanorods induced more active sites for the adsorption of oxygen molecules (O(2)) and O(2) which can be more easily adsorbed on the surface of ZnO nanorods. Furthermore, the conduction channel of ZnO/TiO2 was much narrower as a result of the formation of heterojunction which may further contribute to the enhanced NO2 sensing properties.

  6. Biological conversion of synthesis gas. [Quarterly] technical report No. 2-1, September 5, 1991--December 4, 1991

    SciTech Connect

    Not Available

    1992-01-06

    The anaerobic bacterium Rhodospirillum rubrum has been chosen for catalysis of the biological water gas shift reaction. Two bacteria, Chlorobium thiosulfatophilum and Chlorobium phaeobacteroides, are being evaluated as candidates for H{sub 2}S conversion to elemental sulfur. Since these latter two organisms both grow and convert H{sub 2}S in batch culture using standard basal medium, the choice of a suitable bacterium must be made in consideration of specific growth and uptake rates. Produced elemental sulfur stability against further oxidation to sulfate, and minimal use of H{sub 2} as a producing agent must also be considered. The effects of temperature on the performance of R. rubrum were evaluated. It was found that the cell concentration was highest at temperatures of 25 and 30{degree}C, and that the specific uptake rate was highest at temperatures of 30, 32 and 34{degree}C. No growth was observed at 37{degree}C. Also, temperature did not affect the yield of H{sub 2} from CO. Thus, R. rubrum may be used for biological rates gas shift at any temperature between 30 and 34{degree}C, although growth is maximized at lower temperatures. Preliminary studies with C. thiosulfatophilum showed rapid utilization of H{sub 2}S from the gas and liquid phases with subsequent production of elemental sulfur. Elemental sulfur production interfered with cell concentrations measurements, although a technique has been developed to rectify this problem.

  7. Controllable Low-Temperature Hydrothermal Synthesis and Gas-Sensing Investigation of Crystalline SnO2 Nanoparticles

    NASA Astrophysics Data System (ADS)

    Lu, Ping; Hu, Xiulan; Huang, Huihong; Hu, Ning; Zhang, Jianbo; Shen, Xiaodong

    2016-04-01

    SnO2 nanoparticles have been successfully synthesized by a facile hydrothermal method from SnCl2·2H2O, hexamethylenetetramine, and trisodium citrate in water at 120 °C for 12 h. The effects of surfactant and precipitant on SnO2 synthesis were investigated. SnO2 nanoparticles can be synthesized in the temperature range of 120-180 °C with long reaction time in the presence of trisodium citrate. When NaOH was used as precipitant instead of hexamethylenetetramine, it is difficult to obtain SnO2 nanoparticles at 120 °C in the presence of trisodium citrate. SnO2 nanoparticles with an average size of about 5 nm show good crystallinity and excellent sensitivity to ethanol and acetaldehyde in about 55% relative humidity.

  8. COMPARISON OF SODIUM AND POTASSIUM CARBONATES AS LITHIUM ZIRCONATE MODIFIERS FOR HIGH-TEMPERATURE CARBON DIOXIDE CAPTURE FROM BIOMASS-DERIVED SYNTHESIS GAS

    SciTech Connect

    Olstad, J.L.; Phillips, S.D.

    2009-01-01

    The process of gasifi cation converts biomass into synthesis gas (syngas), which can be used to produce biofuels. Solid-phase sorbents were investigated for the removal of CO2 from a N2/CO2 gas stream using a CO2 concentration similar to that found in a biomass gasifi cation process. During the gasifying process, large amounts of carbon dioxide (CO2) are created along with the syngas. The produced CO2 must be removed before the syngas can be used for fuel synthesis and to avoid the possible formation of unwanted byproducts. A thermogravimetric analyzer was used to test the CO2 absorption rates of sorbents composed of lithium zirconate (Li2ZrO3), as well as mixtures of Li2ZrO3 with potassium carbonate (K2CO3) and sodium carbonate (Na2CO3). The experimental results show that Li2ZrO3 has a low absorption rate, but sorbents containing combinations of Li2ZrO3 and the K2CO3 and Na2CO3 additives have high uptake rates. Using different proportions of K2CO3 and Na2CO3 produces varying uptake rates, so an optimization experiment was performed to obtain an improved sorbent. The CO2 absorption and regeneration stability of the solid-phase sorbents were also examined. A sorbent composed of Li2ZrO3 and 12.1 weight % Na2CO3 was shown to be stable, based on the consistent CO2 uptake rates. Sorbents prepared with Li2ZrO3, 17.6 weight % K2CO3 and 18.1 weight % Na2CO3 showed instability during regeneration cycles in air at 800 °C. Sorbent stability improved during regeneration cycles at 700 °C. Further testing of the Li2ZrO3 sorbent under actual syngas conditions, including higher pressure and composition, should be done. Once the optimum sorbent has been found, a suitable support will be needed to use the sorbent in an actual reactor.

  9. Novel synthesis of bismuth-based adsorbents for the removal of 129I in off-gas

    NASA Astrophysics Data System (ADS)

    Yang, Jae Hwan; Shin, Jin Myeong; Park, Jang Jin; Park, Geun Il; Yim, Man Sung

    2015-02-01

    New adsorbents based on bismuth were investigated for the capture of iodine-129 (129I) in off-gas produced from spent fuel reprocessing. Porous bulky materials were synthesized with polyvinyl alcohol (PVA) as a sacrificial template. Our findings showed that the iodine trapping capacity of as-synthesized samples could reach 1.9-fold that of commercial silver-exchanged zeolite (AgX). The thermodynamic stability of the reaction products explains the high removal efficiency of iodine. We also found that the pore volume of each sample was closely related to the ratio of the reaction products.

  10. Facile synthesis of α-Fe{sub 2}O{sub 3} nanoparticles for high-performance CO gas sensor

    SciTech Connect

    Cuong, Nguyen Duc; Khieu, Dinh Quang; Hoa, Tran Thai; Quang, Duong Tuan; Viet, Pham Hung; Lam, Tran Dai; Hoa, Nguyen Duc; Hieu, Nguyen Van

    2015-08-15

    Highlights: • We have demonstrated a facile method to prepare Fe{sub 2}O{sub 3} nanoparticles. • The gas sensing properties of α-Fe{sub 2}O{sub 3} have been invested. • The results show potential application of α-Fe{sub 2}O{sub 3} NPs for CO sensors in environmental monitoring. - Abstract: Iron oxide nanoparticles (NPs) were prepared via a simple hydrothermal method for high performance CO gas sensor. The synthesized α-Fe{sub 2}O{sub 3} NPs were characterized by X-ray diffraction, nitrogen adsorption/desorption isotherm, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED). The SEM, TEM results revealed that obtained α-Fe{sub 2}O{sub 3} particles had a peanut-like geometry with hemispherical ends. The response of the α-Fe{sub 2}O{sub 3} NPs based sensor to carbon monoxide (CO) and various concentrations of other gases were measured at different temperatures. It found that the sensor based on the peanut-like α-Fe{sub 2}O{sub 3} NPs exhibited high response, fast response–recovery, and good selectivity to CO at 300 °C. The experimental results clearly demonstrated the potential application of α-Fe{sub 2}O{sub 3} NPs as a good sensing material in the fabrication of CO sensor.

  11. Synthesis and morphology of iron-iron oxide core-shell nanoparticles produced by high pressure gas condensation

    NASA Astrophysics Data System (ADS)

    Xing, Lijuan; ten Brink, Gert H.; Chen, Bin; Schmidt, Franz P.; Haberfehlner, Georg; Hofer, Ferdinand; Kooi, Bart J.; Palasantzas, George

    2016-05-01

    Core-shell structured Fe nanoparticles (NPs) produced by high pressure magnetron sputtering gas condensation were studied using transmission electron microscopy (TEM) techniques, electron diffraction, electron energy-loss spectroscopy (EELS), tomographic reconstruction, and Wulff shape construction analysis. The core-shell structure, which is composed of an Fe core surrounded by a maghemite (γ-Fe2O3) and/or magnetite (Fe3O4) shell, was confirmed by fast Fourier transform (FFT) analysis combined with EELS. It was found that the particle size and shape strongly depend on the gas environment. Moreover, extensive analysis showed that NPs with a size between 10-20 nm possess a truncated cubic morphology, which is confined by the 6 {100} planes that are truncated by the 12 {110} planes at different degrees. For NPs larger than 20 nm, the rhombic dodecahedron defined by the 12 {110} planes is the predominant crystal shape, while truncated rhombic dodecahedrons, as well as non-truncated and truncated cubic NPs, were also observed. The NPs without truncation showed a characteristic inward relaxation indicating that besides thermodynamics kinetics also plays a crucial role during particle growth.

  12. Synthesis and morphology of iron-iron oxide core-shell nanoparticles produced by high pressure gas condensation.

    PubMed

    Xing, Lijuan; Ten Brink, Gert H; Chen, Bin; Schmidt, Franz P; Haberfehlner, Georg; Hofer, Ferdinand; Kooi, Bart J; Palasantzas, George

    2016-05-27

    Core-shell structured Fe nanoparticles (NPs) produced by high pressure magnetron sputtering gas condensation were studied using transmission electron microscopy (TEM) techniques, electron diffraction, electron energy-loss spectroscopy (EELS), tomographic reconstruction, and Wulff shape construction analysis. The core-shell structure, which is composed of an Fe core surrounded by a maghemite (γ-Fe2O3) and/or magnetite (Fe3O4) shell, was confirmed by fast Fourier transform (FFT) analysis combined with EELS. It was found that the particle size and shape strongly depend on the gas environment. Moreover, extensive analysis showed that NPs with a size between 10-20 nm possess a truncated cubic morphology, which is confined by the 6 {100} planes that are truncated by the 12 {110} planes at different degrees. For NPs larger than 20 nm, the rhombic dodecahedron defined by the 12 {110} planes is the predominant crystal shape, while truncated rhombic dodecahedrons, as well as non-truncated and truncated cubic NPs, were also observed. The NPs without truncation showed a characteristic inward relaxation indicating that besides thermodynamics kinetics also plays a crucial role during particle growth.

  13. Synthesis of nickel-incorporated larch-based carbon membranes with controllable porous structure for gas separation

    NASA Astrophysics Data System (ADS)

    Zhao, Xin; Li, Wei; Huang, Zhanhua; Liu, Shouxin

    2015-11-01

    Ni-incorporated larch-based carbon membranes have been synthesized by introducing the Ni(NO3)2 into the liquefied larch using liquefied larch sawdust as precursors and F127 as the soft template. The porous structure can be tailored by the amount of Ni(NO3)2, and the Ni and NiO nanoparticles with a size of 10 nm incorporated in the carbon frameworks. The increase in Ni(NO3)2 content can lead to the formation of disordered porous structure and shrinkage of carbon frameworks. The Ni-incorporated carbon membranes with largest pores possess highest gas permeation for N2, CO2, and O2 of 37.5, 19.8, and 55.5 m3 cm/m2 h kPa, which is larger than that of the pure carbon membranes, respectively. However, the poor ordered porous structure caused by adding large amount of Ni(NO3)2 can reduce the gas separation performance, which is attributed to the weaken of the molecular sieve function. The results indicate that the incorporation of few nanoparticles into larch-based carbon membranes can improve molecular sieve function.

  14. De novo synthesis of a metal-organic framework material featuring ultrahigh surface area and gas storage capacities.

    PubMed

    Farha, Omar K; Yazaydın, A Özgür; Eryazici, Ibrahim; Malliakas, Christos D; Hauser, Brad G; Kanatzidis, Mercouri G; Nguyen, SonBinh T; Snurr, Randall Q; Hupp, Joseph T

    2010-11-01

    Metal-organic frameworks--a class of porous hybrid materials built from metal ions and organic bridges--have recently shown great promise for a wide variety of applications. The large choice of building blocks means that the structures and pore characteristics of the metal-organic frameworks can be tuned relatively easily. However, despite much research, it remains challenging to prepare frameworks specifically tailored for particular applications. Here, we have used computational modelling to design and predictively characterize a metal-organic framework (NU-100) with a particularly high surface area. Subsequent experimental synthesis yielded a material, matching the calculated structure, with a high BET surface area (6,143 m(2) g(-1)). Furthermore, sorption measurements revealed that the material had high storage capacities for hydrogen (164 mg g(-1)) and carbon dioxide (2,315 mg g(-1))--gases of high importance in the contexts of clean energy and climate alteration, respectively--in excellent agreement with predictions from modelling.

  15. GAS PHASE SYNTHESIS OF (ISO)QUINOLINE AND ITS ROLE IN THE FORMATION OF NUCLEOBASES IN THE INTERSTELLAR MEDIUM

    SciTech Connect

    Parker, Dorian S. N.; Kaiser, Ralf I.; Kostko, Oleg; Troy, Tyler P.; Ahmed, Musahid; Mebel, Alexander M.; Tielens, Alexander G. G. M.

    2015-04-20

    Nitrogen-substituted polycyclic aromatic hydrocarbons (NPAHs) have been proposed to play a key role in the astrochemical evolution of the interstellar medium, yet the formation mechanisms of even their simplest prototypes—quinoline and isoquinoline—remain elusive. Here, we reveal a novel concept that under high temperature conditions representing circumstellar envelopes of carbon stars, (iso)quinoline can be synthesized via the reaction of pyridyl radicals with two acetylene molecules. The facile gas phase formation of (iso)quinoline in circumstellar envelopes defines a hitherto elusive reaction class synthesizing aromatic structures with embedded nitrogen atoms that are essential building blocks in contemporary biological-structural motifs. Once ejected from circumstellar shells and incorporated into icy interstellar grains in cold molecular clouds, these NPAHs can be functionalized by photo processing forming nucleobase-type structures as sampled in the Murchison meteorite.

  16. Gas phase studies of the Pesci decarboxylation reaction: synthesis, structure, and unimolecular and bimolecular reactivity of organometallic ions.

    PubMed

    O'Hair, Richard A J; Rijs, Nicole J

    2015-02-17

    CONSPECTUS: Decarboxylation chemistry has a rich history, and in more recent times, it has been recruited in the quest to develop cheaper, cleaner, and more efficient bond-coupling reactions. Thus, over the past two decades, there has been intense investigation into new metal-catalyzed reactions of carboxylic substrates. Understanding the elementary steps of metal-mediated transformations is at the heart of inventing new reactions and improving the performance of existing ones. Fortunately, during the same time period, there has been a convergence in mass spectrometry (MS) techniques, which allows these catalytic processes to be examined efficiently in the gas phase. Thus, electrospray ionization (ESI) sources have been combined with ion-trap mass spectrometers, which in turn have been modified to either accept radiation from tunable OPO lasers for spectroscopy based structural assignment of ions or to allow the study of ion-molecule reactions (IMR). The resultant "complete" gas-phase chemical laboratories provide a platform to study the elementary steps of metal-catalyzed decarboxylation reactions in exquisite detail. In this Account, we illustrate how the powerful combination of ion trap mass spectrometry experiments and DFT calculations can be systematically used to examine the formation of organometallic ions and their chemical transformations. Specifically, ESI-MS allows the transfer of inorganic carboxylate complexes, [RCO2M(L)n](x), (x = charge) from the condensed to the gas phase. These mass selected ions serve as precursors to organometallic ions [RM(L)n](x) via neutral extrusion of CO2, accessible by slow heating in the ion trap using collision induced dissociation (CID). This approach provides access to an array of organometallic ions with well-defined stoichiometry. In terms of understanding the decarboxylation process, we highlight the role of the metal center (M), the organic group (R), and the auxiliary ligand (L), along with cluster nuclearity, in

  17. Novel Approaches to the Production of Higher Alcohols From Synthesis Gas. Quarterly report, January 1 - March 31, 1997

    SciTech Connect

    Roberts, George W

    1998-12-11

    A modified analytical system was assembled and calibrated, in preparation for a second run with cesium (Cs)-promoted "zinc chromite" catalyst. A new column for the on-line gas chromatography (GC) was purchased for the analysis of various light olefin and paraffin isomers. A run was carried out in the continuous stirred autoclave using the Cs-promoted catalyst. Decahydronaphfialene was used as the slurry liquid. Reaction conditions were 375°C, 2000 psig total pressure, 0.5 H₂/CO ratio, and 5000 sL/Kg (cat.)-hr. Analysis of the data from this run is in progress. A manuscript on the thermal stability of potential slurry liquids was submitted to 'Industrial and Engineering Chemistry Research,' and a paper was presented at the 1997 Spring National Meeting of the American Institute of Chemical Engineers, Houston, Texas.

  18. Synthesis, structural and conformational properties, and gas phase reactivity of 1,4-dihydropyridine ester and ketone derivatives.

    PubMed

    Giorgi, Gianluca; Adamo, Mauro F A; Ponticelli, Fabio; Ventura, Antonio

    2010-12-07

    A new series of 4-aryl-2,6-dimethyl-1,4-dihydropyridines, characterized by ester or ketone functions at positions 3 and 5, has been synthesized. Structural and conformational properties, concerning the dihydropyridine ring and the orientation (synplanar/antiperiplanar) of the substituents have been investigated in their crystal structure and in solution by nuclear magnetic resonance. Evaluation of intermolecular and hydrogen bonding interactions as well as packing features, have been also carried out, evidencing interesting packing motifs. Their gas phase reactivity, as protonated and deprotonated molecules, has been investigated by electrospray ionization, high resolution and collision-induced dissociation multiple stage mass spectrometry. Deydrogenation reactions have been observed as a function of the capillary voltage.

  19. Bench-scale demonstration of biological production of ethanol from coal synthesis gas. Quarterly report, April 1, 1993--June 30, 1993

    SciTech Connect

    Not Available

    1993-09-01

    Three bacteria, Clostridium ljungdahlii and isolates ERI-8 and 0-52, have been utilized in CSTR studies in order to directly compare the performance of the bacteria in continuous culture in converting synthesis gas components to ethanol. C. ljungdahlii is able to produce higher concentrations of ethanol than the other bacteria, largely because medium development with this bacterium has been ongoing for 2--3 years. However, both of the ERI isolates are quite promising for ethanol production and, therefore, will be studied further in the CSTR. A comparison of the energy costs for various ethanol recovery techniques has been made for use in the bench scale system. The techniques considered include direct distillation, extraction with various solvents followed by distillation, air stripping followed by distillation, pervaporation followed by distillation, reverse osmosis and temperature swing extraction. Extraction with a solvent possessing a relatively high distribution coefficient for ethanol and a high separation factor (relative ability to extract ethanol in favor of water), followed by distillation, is the most desirable technology.

  20. Elimination of acetate production to improve ethanol yield during continuous synthesis gas fermentation by engineered biocatalyst Clostridium sp. MTEtOH550.

    PubMed

    Berzin, Vel; Kiriukhin, Michael; Tyurin, Michael

    2012-05-01

    Acetogen strain Clostridum sp. MT653 produced acetate 273 mM (p < 0.005) and ethanol 250 mM (p < 0.005) from synthesis gas blend mixture of 64% CO and 36% H(2). Clostridum sp. MT653 was metabolically engineered to the biocatalyst strain Clostridium sp. MTEtOH550. The biocatalyst increased ethanol yield to 590 mM with no acetate production during single-stage continuous syngas fermentation due to expression of synthetic adh cloned in a multi-copy number expression vector. The acetate production was eliminated by inactivation of the pta gene in Clostridium sp. MTEtOH550. Gene introduction and gene elimination were achieved only using Syngas Biofuels Energy, Inc. electroporation generator. The electrotransformation efficiencies were 8.0 ± 0.2 × 10(6) per microgram of transforming DNA of the expression vector at cell viability ~15%. The frequency of suicidal vector integration to inactivate pta was ~10(-5) per the number of recipient cells. This is the first report on elimination of acetate production and overexpression of synthetic adh gene to engineer acetogen biocatalyst for selective biofuel ethanol production during continuous syngas fermentation.

  1. In situ Raman and pulse reaction study on the partial oxidation of methane to synthesis gas over a Pt/Al2O3 catalyst.

    PubMed

    Wang, Mei-Liu; Zheng, Hao-Zhuan; Li, Jian-Mei; Weng, Wei-Zheng; Xia, Wen-Sheng; Huang, Chuan-Jing; Wan, Hui-Lin

    2011-02-01

    Catalytic partial oxidation of methane (POM) to synthesis gas (syngas) over Pt/Al(2)O(3) was investigated by in situ microprobe Raman and pulse reaction methods with attention focused on the mechanism of syngas formation in the oxidation zone (i.e., the catalyst zone in which O(2) was still available in the reaction feed). It was found that the amount of platinum oxide in the catalyst under POM conditions was below the detection level of Raman spectroscopy. Raman bands of carbon species that originated from methane dissociation were detected at the entrance of the catalyst bed under working conditions. The results of the pulse reaction study on POM as well as steam and CO(2) reforming of methane at 700 °C with a contact time of less than 1 ms over the catalyst suggest that pyrolysis of methane on reduced platinum sites followed by coupling of two surface hydrogen atoms to H(2) and partial oxidation of surface carbon species to CO are the major reactions responsible for syngas formation in the oxidation zone. Under the experimental conditions, steam and CO(2) reforming of methane play only a minor role in syngas formation in the same reaction zone. The contribution of the last two reactions increases with increasing contact time.

  2. Development of a solid-phase extraction/gas chromatographic-mass spectrometric method for quantification of succinic acid in nucleoside derivatives for oligonucleotide synthesis.

    PubMed

    Stenholm, Ake; Drevin, Ingrid; Lundgren, Michael

    2005-04-08

    A solid-phase extraction (SPE)/gas chromatographic-mass spectrometric (GC-MS) method was developed for analysing residual succinic acid in nucleoside derivatives to be used in oligonucleotide synthesis. Use of a SPE protocol, enabled most of the derivatives to be trapped, thereby creating eluates enriched in succinic acid. GC-MS was used to quantify the amount of residual succinic acid in four different nucleoside preparations, with succinate concentrations varying from 0.18 to 0.24% (w/w). The within-day repeatability of the method was found to be 1.25% RSD. A linear relationship was observed between the amount of succinic acid in the sample and the GC-MS peak area, with a correlation coefficient of 0.9997 in the concentration interval 0.05-2.5% (w/w). Recoveries were measured by the addition of internal standards to working solutions and varied between 99.8 and 102.6%.

  3. Nanoengineering Ni(x)Fe(1-x) catalysts for gas-phase, selective synthesis of semiconducting single-walled carbon nanotubes.

    PubMed

    Chiang, Wei-Hung; Sakr, Mohammed; Gao, Xuan P A; Sankaran, R Mohan

    2009-12-22

    The inhomogeneity of as-grown single-walled carbon nanotubes (SWCNTs), in terms of chiral structure, is a major obstacle to integration of these novel materials in advanced electronics. While separation methods have circumvented this problem, current synthesis approaches must be refined for large-scale production of SWCNTs with uniform properties. In addition, it is highly desirable to alter the initial chirality distribution which constrains fundamental study and applications. Here, we demonstrate that semiconducting SWCNTs are selectively produced in the gas phase by engineering catalysts at the nanoscale with precise size and composition. The semiconducting content in as-grown mixtures of SWCNTs is assessed by UV-visible-NIR absorbance and micro-Raman spectroscopy and reaches a maximum purity of 90% for samples catalyzed by Ni(0.27)Fe(0.73) nanoparticles (2.0 nm mean diameter). Electrical studies are performed on thin film transistors (TFTs) fabricated from as-grown SWCNTs and reveal high on/off current ratios of 10(3).

  4. The Role of Rhenium in the Conversion of Glycerol to Synthesis Gas Over Carbon Supported Platinum-Rhenium Catalysts

    SciTech Connect

    Kunkes, E.; Simonetti, D; Dumesic, J; Pyrz, W; Chen, J

    2008-01-01

    Reaction kinetics measurements were carried out to study the conversion of aqueous solutions of glycerol (30 and 80 wt%) over carbon-supported Pt and Pt-Re catalysts at temperatures from 483 to 523 K. The results of these studies show that the turnover frequencies for production of H2, CO, CO2, and light alkanes (primarily methane) all increase upon the addition of Re to Pt/C catalysts. The molar ratio of H2/CO increases, while the CO/CO2 ratio decreases with Re addition, indicating increased rate of water-gas shift. For glycerol conversion over a Pt-Re/C catalyst with an atomic Pt:Re ratio of 1:1, increasing pressure or decreasing temperature leads to an increase in the production of alkanes and light oxygenated hydrocarbons (ethanol, methanol, propanediols, and acetone) at the expense of CO and CO2. Temperature-programmed desorption studies and microcalorimetric measurements indicate that addition of Re to Pt modifies the interaction of CO with surface sites. X-ray absorption spectroscopy and transmission electron microscopy studies provide evidence indicating that Pt-Re/C catalysts consist primarily of bimetallic nanoparticles with sizes below 2 nm, and Re inhibits the sintering of these nanoparticles during reaction conditions for glycerol conversion. The results of these reaction kinetic studies and characterization studies indicate that the performance of Pt-Re/C catalysts for glycerol conversion is related to the formation of Pt-Re nanoparticles, for which Re promotes the overall rate of glycerol reforming by reducing the binding energy of CO to Pt, thereby leading to less extensive blocking of surface sites by reaction intermediates and/or products. In addition, the presence of Re facilitates water-gas shift and Csingle bondO bond cleavage reactions.

  5. Synthesis of activated carbon from oil fly ash for removal of H2S from gas stream

    NASA Astrophysics Data System (ADS)

    Aslam, Zaheer; Shawabkeh, Reyad A.; Hussein, Ibnelwaleed A.; Al-Baghli, Nadhir; Eic, Mladen

    2015-02-01

    Activated carbon (AC) is made from waste oil fly ash (OFA) which is produced in large quantities from power generation plants through combustion of heavy fuel oil. OFA contains ∼80% carbon that makes it suitable for producing AC by physicochemical treatments using a mixture of HNO3, H2SO4, and H3PO4 acids to remove non-carbonaceous impurities. The acid treated OFA is then activated by CO2 at 990 °C. The physico-chemical treatments of OFA have increased the surface area from 4 to 375 m2/g. Surface morphology and pore volume of AC are characterized by combined SEM and EDX techniques. Elemental analysis shows that sulfur content is reduced from 7.1 wt% in untreated OFA to 0.51 wt% for the treated OFA. The AC is further treated with HNO3 and NH4OH solutions in order to attach the carboxylic and amine groups on the surface, respectively. FTIR characterization is used to confirm the presence of the functional groups on the surface of AC at different stages of its development. The performance of functionalized AC samples is tested for the removal of H2S from a synthetic natural gas by carrying out breakthrough experiments. The results from these tests have shown maximum adsorption capacity of 0.3001 mg/g for NH4OH functionalized activated carbon with 86.43% regeneration efficiency. The ammonium hydroxide treated AC is found to be more effective for H2S removal than acid treated AC as confirmed by breakthrough experiments. The results indicate that the presence of more acidic functionalities on the surface reduces the H2S adsorption efficiency from the gas mixture.

  6. Synthesis and characterization of nickel and zinc ferrite nanocatalysts for decomposition of CO2 greenhouse effect gas.

    PubMed

    Lin, Kuen-Song; Adhikari, Abhijit Krishna; Wang, Chi-Yu; Hsu, Pei-Ju; Chan, Ho-Yang

    2013-04-01

    The decomposition of CO2 over oxygen deficient nickel ferrite nanoparticles (NFNs) and zinc ferrite nanoparticles (ZFNs) at 573 K was studied. The oxidation states with fine structure of Fe/Ni or Fe/Zn species were also measured in NFNs and ZFNs catalysts, respectively. Oxygen deficiency of catalysts was obtained by reduction in hydrogen. Decomposition of CO2 into carbon and oxygen has been carried out within few minutes when it comes into contact with oxygen deficient catalysts through incorporation of oxygen into ferrite nanoparticles. Oxygen and carbon rather than CO were produced in the decomposition process. The complete decomposition of CO2 was possible because of higher degree of oxygen deficiency andsurface-to-volume ratio of the catalysts. The pre-edge XANES spectra of Fe species in both catalysts exhibit an absorbance feature at 7114 eV for the 1s to 3d transition which is forbidden by the selection rule in case of perfect octahedral symmetry. The EXAFS data showed that the NFNs had two central Fe atoms coordinated by primarily Fe-O and Fe-Fe with bond distances of 1.871 and 3.051 angstroms, respectively. In case of ZFNs these values are 1.889 and 3.062 A, respectively. Methane gas was produced during the reactivation of NFNs by flowing hydrogen gas. Decomposition of CO2, moreover, recovery of valuable methane using heat energy of offgas produced from power generation plant or steel industry is an appealing alternative for energy recovery.

  7. Development of alternative fuels from coal-derived synthesis gas: Final topical report, demonstration of one-step slurry-phase process for the co-production of methanol and isobutanol

    SciTech Connect

    1996-06-01

    Liquid phase co-production of methanol and isobutanol (LPIBOH) was de, demonstrated at DOE`s Alternative Fuels Development Unit (AFDU) in LaPorte, Texas. Methanol and isobutanol are key intermediates in a synthesis gas-based route to methyl t-butyl ether (MTBE). The technology was demonstrated in a new 18 in. slurry bubble-column reactor that was designed to demonstrate higher pressures and temperatures,higher gas superficial velocities, and lower gas hourly space velocities--all of which are conducive to obtaining optimal isobutanol yield. The integration of the new reactor into the AFDU included the addition of a high-pressure synthesis gas compressor, a high-pressure hydrogen feed source, and a closed-loop methanol- solvent absorption system to remove CO{sub 2} from the unconverted synthesis gas. These modifications were completed in January 1994. The LPIBOH run followed after a short turnaround. It employed a cesium- promoted Cu/ZnO/Al{sub 2}O{sub 3} catalyst developed in Air Products` laboratories and subsequently scaled up to a production- sized batch. Over a thirteen day campaign on simulated Shell gasifier gas, the catalyst and reactor system were tested at a matrix of pressures (750, 1300, 1735 psig) and space velocities (3000, 5000, 8200 sL/kg-hr), representing numerous first-of-a-kind run conditions for the AFDU. Inlet gas superficial velocities spanned an impressive 0.16 to 1.0 ft/sec. Stable reactor performance for a full twelve-hour data period at 1.0 ft/sec was another significant milestone for the liquid phase technology program. Apart from the catalyst deactivation, the run successfully demonstrated mixed alcohol synthesis in a slurry bubble-column reactor, as well as all of the new equipment installed for the trial. Although the full capabilities of the new oxygenates system will not be tested until future runs, the design objectives for the modifications were met with respect to the LPIBOH run.

  8. Synthesis of single-walled carbon nanotubes from Pd catalysts by gas source method using ethanol in high vacuum

    NASA Astrophysics Data System (ADS)

    Kozawa, Akinari; Saida, Takahiro; Naritsuka, Shigeya; Maruyama, Takahiro

    2016-01-01

    We carried out single-walled carbon nanotube (SWCNT) growth at 600 °C using Pd catalysts by the alcohol gas source method. When Pd catalysts deposited on SiO2/Si substrates were used, the G band in the Raman spectra was broad and weak RBM peaks were observed at ethanol pressures between 1 × 10-3 and 1 × 10-1 Pa. On the other hand, using Al2Ox buffer layers, a sharp G band with a shoulder peak (G- peak) and several radial breathing mode (RBM) peaks were observed, which indicates the growth of SWCNTs. Scanning electron microscopy (SEM) observation showed that dense web like SWCNTs were formed, and the diameters of SWCNTs estimated from the wavenumbers of RBM peaks were 1.3-2.9 nm, which were larger than those from Pt catalysts. Transmission electron microscopy (TEM) observation showed that the larger migration distance of Pd caused an enlargement of catalyst particle sizes, resulting in the larger diameters of SWCNTs from Pd catalysts.

  9. Gas-phase synthesis and structure of monomeric ZnOH: a model species for metalloenzymes and catalytic surfaces.

    PubMed

    Zack, Lindsay N; Sun, Ming; Bucchino, Matthew P; Clouthier, Dennis J; Ziurys, Lucy M

    2012-02-16

    Monomeric ZnOH has been studied for the first time using millimeter and microwave gas-phase spectroscopy. ZnOH is important in surface processes and at the active site of the enzyme carbonic anhydrase. In the millimeter-wave direct-absorption experiments, ZnOH was synthesized by reacting zinc vapor, produced in a Broida-type oven, with water. In the Fourier-transform microwave measurements, ZnOH was produced in a supersonic jet expansion of CH(3)OH and zinc vapor, created by laser ablation. Multiple rotational transitions of six ZnOH isotopologues in their X(2)A' ground states were measured over the frequency range of 22-482 GHz, and splittings due to fine and hyperfine structure were resolved. An asymmetric top pattern was observed in the spectra, showing that ZnOH is bent, indicative of covalent bonding. From these data, spectroscopic constants and an accurate structure were determined. The Zn-O bond length was found to be similar to that in carbonic anhydrase and other model enzyme systems.

  10. Isobutanol-methanol mixtures from synthesis gas. Quarterly technical progress report, 1 April--30 June 30 1996

    SciTech Connect

    1996-07-25

    A series of CuMgCeO{sub x} catalysts have been prepared by coprecipitating the corresponding metal nitrates with a mixed solution of potassium carbonate and potassium hydroxide. Kinetic studies of methanol and ethanol coupling reactions on K-Cu/MgO/CeO{sub 2} and MgO/CeO{sub 2} catalysts indicate that Cu enhances the rates of alcohol dehydrogenation. The cross-coupling reactions of acetaldehyde and {sup 13}C-labeled methanol produce singly-labeled propionaldehyde, suggesting that it forms by the condensation of acetaldehyde and a reactive intermediate derived from methanol. Isobutyraldehyde, a precursor to isobutanol, forms via the condensation of propionaldehyde and a reactive C{sub 1} intermediate resulting from methanol. CO{sub 2}, one of the reaction products, poisons both basic and metal sites on Ce-containing CuMgO{sub x} catalysts, resulting in decreases in the rates of both alcohol dehydrogenation (Cu sites) and chain-growth condensation reactions (basic sites). CO{sub 2} inhibits ethanol dehydrogenation on both low-Cu and high-Cu CuMgCeO{sub x} catalysts; however, CO{sub 2} has no effect on the activity of low-Cu Ce-free Cu-MgO{sub x} catalysts, suggesting that the Cu on CuMgCeO{sub x} catalysts is more likely to be oxidized by CO{sub 2} to Cu{sup +} species that can be subsequently stabilized by CeO{sub 2}. CO{sub 2} effects on high-pressure isobutanol synthesis from CO/H{sub 2} have been studied on low- and high-Cu CuMgCeO{sub x} catalysts at 320{degrees}C and 4.5 MPa. CO{sub 2} addition and removal on low- and high-Cu catalysts show similar directional effects on CO conversion. CO conversion is lower at all space velocities in the presence of CO{sub 2}, and removal Of CO{sub 2} from the feed partially recovers CO conversion. CO{sub 2} decreases methanol and isobutanol productivities on both catalysts. Addition of 1-propanol to CO/H{sub 2} feed increases isobutanol production, suggesting that 1-propanol is a precursor to isobutanol.

  11. Synthesis of one-dimensional SnO2 lines by using electrohydrodynamic jet printing for a NO gas sensor

    NASA Astrophysics Data System (ADS)

    Kim, Chang-Yeoul; Jung, Hyunsung; Choi, Hannah; Choi, Duck-kyun

    2016-01-01

    One-dimensional (1-D) SnO2 lines as a representative semiconducting oxide were formed by using electrohydrodynamic (EHD) jet-printing of a tin chloride pentahydrate and polyvinylpyrrolidone (PVP, 1,200k, Aldrich) solution ink. The 1-D polymer lines, including Sn precursors, were created by controlling the viscosity, that is, the polymer/tin precursor ratio, and by adjusting printing conditions such as the tip-to-substrate distance, the applied voltage, the flow rate of ink and its velocity. The printed lines were dried at 200 °C to get rid of solvent and were finally heat-treated at 600 °C to burn out PVP and form a tin oxide line. We found that the linearity and the shape of the aligned 1-D SnO2 could be controlled by adjusting various parameters such as the viscosity of the precursor solution, the ratio of Sn to the PVP polymer in the solution, the shape of the cone, the size of a droplet, the applied voltage, the working distance, and the flow rate on glass slides and Si wafers with a SiO2 layer. We found that the heat treatment for removal of the polymers should be tailored to produce continuous 1-D SnO2 lines due to the drastic volume reduction (> 90%) of the aligned fibers during the annealing process. The electrical and the NO-gas-sensing properties of the 1-D SnO2 aligned on Si wafers with Au electrode patterns were evaluated.

  12. Synthesis, characterization, and gas-phase fragmentation of rhenium-carbonyl complexes bearing imidazol(in)ium-2-dithiocarboxylate ligands.

    PubMed

    Beltrán, Tomás F; Zaragoza, Guillermo; Delaude, Lionel

    2016-11-15

    Five complexes with the generic formula [ReBr(CO)3(κ(2)-S,S'-S2C·NHC)] were obtained by reacting [ReBr(CO)5] with a set of representative imidazol(in)ium-2-dithiocarboxylate zwitterions. These ligands are the adducts of N-heterocyclic carbenes (NHCs) and carbon disulfide. The monometallic Re(i) compounds were further coupled with Na[Re(CO)5] to afford bimetallic Re(0) species. Depending on the experimental conditions, either octacarbonyl dimers [Re2(CO)8(μ2-κ(1)-S,κ(1)-S'-S2C·NHC)] or hexacarbonyl clusters [Re2(CO)6(κ(2)-S,S'-κ(3)-S,C,S'-S2C·NHC)] were isolated. All the products were fully characterized using various analytical techniques. Single crystal XRD analysis helped establish with certainty the various binding modes exhibited by the NHC·CS2 ligands. With bite angles ranging from ca. 104 to 130°, these zwitterions displayed a remarkable flexibility, which also permitted significant twists of the thiometallated rings to preserve a staggered arrangement of the carbonyl groups in the bimetallic systems. Monitoring the chemical shift of the CS2(-) moiety by (13)C NMR spectroscopy was most useful to detect its change of hapticity upon decarbonylation of the octacarbonyl compounds into hexacarbonyl derivatives. IR spectroscopy was another very convenient tool to identify the type of complex formed in a reaction, based on the pattern of its carbonyl vibration bands. Advanced mass spectrometry techniques showed that all the compounds underwent partial or total decarbonylation in the gas phase with no concomitant fragmentation of the bimetallic assemblies into monometallic ions.

  13. Exploring the Gas Phase Synthesis of the Elusive Class of Boronyls and the Mechanism of Boronyl Radical Reactions under Single Collision Conditions.

    PubMed

    Kaiser, Ralf I; Balucani, Nadia

    2016-12-19

    Until recently, the chemistry of boronyl (BO), a diatomic radical isolectronic with the cyano (CN) species, has remained unknown. The boronyl group is characterized by a boron-oxygen multiple bond, and because of the inherent electron deficiency of the boron atom, boronyls (RBO) are highly reactive and typically only exist in their cyclotrimeric form (RBO)3. Due to their invaluable role as reactants, the isolation of the monomers in gas phase experiments has been extensively sought after by the organic synthesis and physical organic chemistry communities but never achieved. Besides the interests from a physical organic and synthetic point of view, boronyls also play a role as reaction intermediates in boron-assisted rocket propulsion systems. In this Account, we review recent experimental work in which gas phase organo boronyl monomers (RBO) are formed via bimolecular reactions of the boronyl radical (BO) with C2-C6 unsaturated hydrocarbons. The investigated hydrocarbons are widely exploited as fuels, and their reactions with boronyl radicals under single collision conditions lead to the formation of organo boronyls. Our studies also elucidate the mechanisms of their formation reactions thus furnishing a comprehension at the molecular level of this reaction class. The variety of the employed hydrocarbon substrates has allowed us to systematically classify the chemical behavior of the boronyl radicals. With the exception of the case of the dimethylacetylene reaction, the boron monoxide radical versus atomic hydrogen exchange mechanisms were always open leading to the formation of highly unsaturated organo boronyl monomers (RBO), which could be easily identified because they cannot trimerize under single collision conditions. Besides the hydrogen displacement pathway, methylacetylene, dimethylacetylene, and propylene, carrying one or two methyl groups, were also found to eliminate a methyl group. In all systems, the reactions were barrierless, indirect, and initiated

  14. Synthesis of Pure and N-substituted Cyclic Hydrocarbons (e.g. Pyrimidine) via Gas-Phase Ion-Molecule Reactions

    NASA Astrophysics Data System (ADS)

    Bera, Partha P.; Peverati, Roberto; Head-Gordon, Martin; Lee, Timothy J.

    2015-08-01

    Large polyatomic carbonaceous molecules, known as polycyclic aromatic hydrocarbons, are known to exist in the outflows of carbon stars. How these large polyatomic molecules are synthesized in such exotic conditions is, thus far, unknown. Molecular ions, including positive and negative ions, are in relative abundance in the high radiation fields present under such conditions. Hence, barrierless ion-molecule interactions may play a major role in guiding molecules towards each other and initiating reactions. We study these condensation pathways to determine whether they are a viable means of forming large pure hydrocarbon molecules, and nitrogen-containing carbonaceous chains, stacks, and even cyclic compounds. By employing accurate quantum chemical methods we have investigated the processes of growth, structures, nature of bonding, mechanisms, and spectroscopic properties of the ensuing ionic products after pairing small carbon, hydrogen, and nitrogen-containing molecules. We have also studied the ion-neutral association pathways involving pure-carbon molecules e.g. acetylene, ethylene and other hydrocarbons, and their dissociation fragments in a plasma discharge as well as how nitrogen atoms are incorporated into the carbon ring during growth. Specifically, we explored the mechanisms by which the synthesis of pyrimidine will be feasible in the gas phase in conjunction with ion-mobility experiments. We have used accurate ab initio coupled cluster theory, Møller-Plesset and Z-averaged perturbation theories, density functional theory, and coupled cluster theory quantum chemical methods together with large correlation consistent basis sets in these investigations. We found that a series of hydrocarbons with a specific stoichiometric composition prefers cyclic molecule formation rather than chains. Some of the association products we investigated have large oscillator strengths for charge-transfer type electronic excitations in the near infrared and visible regions of

  15. Modification of Inert Gas Condensation Technique to Achieve Wide Area Distribution of Nanoparticles and Synthesis and Characterization of Nanoparticles for Semiconductor Applications

    NASA Astrophysics Data System (ADS)

    Pandya, Sneha G.

    The aim of this dissertation is to develop a versatile experimental technique for synthesis of nanoparticles (NPs), which can be used to deposit NPs in various patterns for semiconductor device applications. In addition, the dissertation also aims at the synthesis and characterization of semiconductor NPs capable of nano-scale temperature measurement and infrared sensing. (Abstract shortened by ProQuest.).

  16. Electrochemical synthesis of ultrafast and gram-scale surfactant-free tellurium nanowires by gas-solid transformation and their applications as supercapacitor electrodes for p-doping of graphene transistors.

    PubMed

    Tsai, Hung-Wei; Yaghoubi, Alireza; Chan, Tsung-Cheng; Wang, Chun-Chieh; Liu, Wei-Ting; Liao, Chien-Neng; Lu, Shih-Yuan; Chen, Lih-Juann; Chueh, Yu-Lun

    2015-05-07

    We herein report a gas-solid transformation mechanism for the surfactant-free synthesis of Te NWs at room temperature by electrolysis of bulk Bi2Te3 using H2Te gas. Te NWs, with an average diameter below 20 nm, grow along the [001] direction due to the unique spiral chains in the crystal structure and show an enhanced Raman scattering effect, a broad absorption band over the range of 350-750 nm and an emission band over the range of 400-700 nm in the photoluminescence spectrum. In terms of device applications, we demonstrate how Te NWs can be directly applied as a p-type dopant source in order to shift the Dirac point in ambipolar field effect graphene transistors. Finally, the favorable capacitive properties of Te NWs are established as supercapacitor electrodes with negligible internal resistance and excellent electrochemical reversibility and a specific capacitance of 24 F g(-1).

  17. Biochemistry of methyl-coenzyme M reductase: the nickel metalloenzyme that catalyzes the final step in synthesis and the first step in anaerobic oxidation of the greenhouse gas methane.

    PubMed

    Ragsdale, Stephen W

    2014-01-01

    Methane, the major component of natural gas, has been in use in human civilization since ancient times as a source of fuel and light. Methanogens are responsible for synthesis of most of the methane found on Earth. The enzyme responsible for catalyzing the chemical step of methanogenesis is methyl-coenzyme M reductase (MCR), a nickel enzyme that contains a tetrapyrrole cofactor called coenzyme F430, which can traverse the Ni(I), (II), and (III) oxidation states. MCR and methanogens are also involved in anaerobic methane oxidation. This review describes structural, kinetic, and computational studies aimed at elucidating the mechanism of MCR. Such studies are expected to impact the many ramifications of methane in our society and environment, including energy production and greenhouse gas warming.

  18. Synthesis gas to alcohols process

    SciTech Connect

    Prada-Silva, G.; Patel, J.A.; Bhattacharya, A.K.

    1988-10-04

    This patent describes a method of preparing a mixture of lower aliphatic alcohols which comprises reacting carbon monoxide and hydrogen in the presence of a sulfide-containing heavy metal catalyst under carbon monoxide-hydrogenation conditions. The catalyst consists of: (1) at least one sulfided heavy metal element selected from the group consisting of molybdenum; tungsten, and rhenium, (2) a sulfided heavy metal element form the group consisting of cobalt, iron, and nickel, (3) a promoter comprising an alkali or alkaline earth element in free or combined form, and optionally, (4) a support, the improvement which comprises improving the selectivity to the alcohols by treating the sulfided heavy metal elements with a nitrogen-containing base prior to treatment with the promoter, the nitrogen-containing base being selected from the group consisting of urea, dimethylolurea, cyanuric acid, melamine, melam, melem, and melon.

  19. Biological conversion of synthesis gas

    SciTech Connect

    Ackerson, M.D.; Clausen, E.C.; Gaddy, J.L.

    1992-06-30

    Overall mass transfer coefficients for CO have been determined in a continuous stirred-tank reactor at agitation rates of 300--700 rpm using a biological system with the photosynthetic bacterium Rhodospirillum rubrum. A non-steady state approach was employed in order to separate mass transfer and kinetic limited regions of the fermentation. As a result, a kinetic model could be developed for specific CO uptake by the culture including the apparent CO inhibition. The maximum specific CO uptake rate found matched the earlier results obtained in batch culture and by other investigators. CO inhibition was more predominant in CSTR culture than in batch culture, perhaps due to CO acclimation. The growth of the photosynthetic bacterium Chlorobium thiosulfatophilum on CO[sub 2] has been studied at light intensities ranging from 27-1723 lux in batch culture. Modeling results indicate that growth is dependent upon light intensity according to a Monod type relationship.

  20. CERTAIN CHARACTERISTICS OF A HIGH-FREQUENCY INDUCTION GAS DISCHARGE AND PECULIARITIES OF ITS APPLICATION FOR SYNTHESIS OF REFRACTORY DIELECTRIC CRYSTALS,

    DTIC Science & Technology

    walls are investigated and the plasma jet produced by a gun with sectional metal walls is examined. Synthesis of crystals in a plasma jet by the Verneuil method and the zone recrystallization procedure is discussed.

  1. Morphology controlled synthesis of platinum nanoparticles performed on the surface of graphene oxide using a gas-liquid interfacial reaction and its application for high-performance electrochemical sensing.

    PubMed

    Bai, Wushuang; Sheng, Qinglin; Zheng, Jianbin

    2016-07-21

    In this paper, we report a novel morphology-controlled synthetic method. Platinum (Pt) nanoparticles with three kinds of morphology (aggregation-like, cube-like and globular) were grown on the surface of graphene oxide (GO) using a simple gas-liquid interfacial reaction and Pt/GO nanocomposites were obtained successfully. According to the experimental results, the morphology of the Pt nanoparticles can be controlled by adjusting the reaction temperature with the protection of chitosan. The obtained Pt/GO nanocomposites were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD) and fourier transform infrared spectroscopy (FTIR). Then the Pt/GO nanocomposites with the three kinds of morphology were all used to fabricate electrochemical sensors. The electrochemical experimental results indicated that compared with various reported electrochemical sensors, the Pt/GO modified sensors in this work exhibit a low detection limit, high sensitivity and an extra wide linear range for the detection of nitrite. In addition, the synthesis of Pt particles based on a gas-liquid interfacial reaction provides a new platform for the controllable synthesis of nanomaterials.

  2. Preliminary screening: Technical and economic assessment of synthesis gas to fuels and chemicals with emphasis on the potential for biomass-derived syngas

    SciTech Connect

    Spath, P. L.; Dayton, D. C.

    2003-12-01

    This report reviews the many syngas to products processes and summarizes the technology status and description, chemistry, catalysts, reactors, gas cleanliness requirements, process and environmental performances, and economics.

  3. Synthesis of acrylates. Quarterly progress report, April 1, 1995--June 30, 1995

    SciTech Connect

    1995-09-05

    The objective of this research is to develop a condensation/oxidation route for the synthesis of acrylates/methacrylates from coal-derived synthesis gas. This quarter work continued on the development of catalysts for propionate synthesis.

  4. Sensitivity of Fischer-Tropsch Synthesis and Water-Gas Shift Catalysts to Poisons from High-Temperature High-Pressure Entrained-Flow (EF) Oxygen-Blown Gasifier Gasification of Coal/Biomass Mixtures

    SciTech Connect

    Burton Davis; Gary Jacobs; Wenping Ma; Dennis Sparks; Khalid Azzam; Janet Chakkamadathil Mohandas; Wilson Shafer; Venkat Ramana Rao Pendyala

    2011-09-30

    There has been a recent shift in interest in converting not only natural gas and coal derived syngas to Fischer-Tropsch synthesis products, but also converting biomass-derived syngas, as well as syngas derived from coal and biomass mixtures. As such, conventional catalysts based on iron and cobalt may not be suitable without proper development. This is because, while ash, sulfur compounds, traces of metals, halide compounds, and nitrogen-containing chemicals will likely be lower in concentration in syngas derived from mixtures of coal and biomass (i.e., using entrained-flow oxygen-blown gasifier gasification gasification) than solely from coal, other compounds may actually be increased. Of particular concern are compounds containing alkali chemicals like the chlorides of sodium and potassium. In the first year, University of Kentucky Center for Applied Energy Research (UK-CAER) researchers completed a number of tasks aimed at evaluating the sensitivity of cobalt and iron-based Fischer-Tropsch synthesis (FT) catalysts and a commercial iron-chromia high temperature water-gas shift catalyst (WGS) to alkali halides. This included the preparation of large batches of 0.5%Pt-25%Co/Al{sub 2}O{sub 3} and 100Fe: 5.1Si: 3.0K: 2.0Cu (high alpha) catalysts that were split up among the four different entities participating in the overall project; the testing of the catalysts under clean FT and WGS conditions; the testing of the Fe-Cr WGS catalyst under conditions of co-feeding NaCl and KCl; and the construction and start-up of the continuously stirred tank reactors (CSTRs) for poisoning investigations. In the second and third years, researchers from the University of Kentucky Center for Applied Energy Research (UK-CAER) continued the project by evaluating the sensitivity of a commercial iron-chromia high temperature water-gas shift catalyst (WGS) to a number of different compounds, including KHCO{sub 3}, NaHCO{sub 3}, HCl, HBr, HF, H{sub 2}S, NH{sub 3}, and a combination of H

  5. Novel approaches to the production of higher alcohols from synthesis gas. Quarterly technical progress report number 13, 1 October--31 December 1993

    SciTech Connect

    Not Available

    1994-07-06

    The mass balances from the September, 1993 methanol synthesis run closed to within {+-}5%, indicating that the analytical techniques and measurement procedures that have been developed to date are accurate and reliable. However, methanol production was severely depressed due to catalyst poisoning, probably by metal carbonyls. Thermodynamic calculations show that the current carbonyl traps are not suitable for methanol synthesis service. X-ray photoelectron spectroscopy analysis showed essentially no carbon on the poisoned catalyst from the September, 1993 methanol synthesis run, as compared with the high carbon levels on the spent catalyst from the April, 1993 methanol synthesis run. Experiments showed that oil foaming can occur at ambient temperatures. New procedures for initial reactor pressurization/depressurization have been developed. Infrared spectroscopy of boiled mineral oils showed the presence of unsaturated carbon chains. The extent of unsaturation is not yet known. A test of a new overhead system on the stirred autoclave reactor showed a marked improvement in oil retention within the reactor.

  6. Sensitivity of Fischer-Tropsch Synthesis and Water-Gas Shift Catalystes to Poisons form High-Temperature High-Pressure Entrained-Flow (EF) Oxygen-Blown Gasifier Gasification of Coal/Biomass Mixtures

    SciTech Connect

    Burton Davis; Gary Jacobs; Wenping Ma; Khalid Azzam; Janet ChakkamadathilMohandas; Wilson Shafer

    2009-09-30

    There has been a recent shift in interest in converting not only natural gas and coal derived syngas to Fischer-Tropsch synthesis products, but also converting biomass-derived syngas, as well as syngas derived from coal and biomass mixtures. As such, conventional catalysts based on iron and cobalt may not be suitable without proper development. This is because, while ash, sulfur compounds, traces of metals, halide compounds, and nitrogen-containing chemicals will likely be lower in concentration in syngas derived from mixtures of coal and biomass (i.e., using entrained-flow oxygen-blown gasifier gasification gasification) than solely from coal, other compounds may actually be increased. Of particular concern are compounds containing alkali chemicals like the chlorides of sodium and potassium. In the first year, University of Kentucky Center for Applied Energy Research (UK-CAER) researchers completed a number of tasks aimed at evaluating the sensitivity of cobalt and iron-based Fischer-Tropsch synthesis (FT) catalysts and a commercial iron-chromia high temperature water-gas shift catalyst (WGS) to alkali halides. This included the preparation of large batches of 0.5%Pt-25%Co/Al{sub 2}O{sub 3} and 100Fe: 5.1Si: 3.0K: 2.0Cu (high alpha) catalysts that were split up among the four different entities participating in the overall project; the testing of the catalysts under clean FT and WGS conditions; the testing of the Fe-Cr WGS catalyst under conditions of co-feeding NaCl and KCl; and the construction and start-up of the continuously stirred tank reactors (CSTRs) for poisoning investigations.

  7. Sensitivity of Fischer-Tropsch Synthesis and Water-Gas Shift Catalysts to Poisons from High-Temperature High-Pressure Entrained-Flow (EF) Oxygen-Blown Gasifier Gasification of Coal/Biomass Mixtures

    SciTech Connect

    Burtron Davis; Gary Jacobs; Wenping Ma; Khalid Azzam; Dennis Sparks; Wilson Shafer

    2010-09-30

    The successful adaptation of conventional cobalt and iron-based Fischer-Tropsch synthesis catalysts for use in converting biomass-derived syngas hinges in part on understanding their susceptibility to byproducts produced during the biomass gasification process. With the possibility that oil production will peak in the near future, and due to concerns in maintaining energy security, the conversion of biomass-derived syngas and syngas derived from coal/biomass blends to Fischer-Tropsch synthesis products to liquid fuels may provide a sustainable path forward, especially considering if carbon sequestration can be successfully demonstrated. However, one current drawback is that it is unknown whether conventional catalysts based on iron and cobalt will be suitable without proper development because, while ash, sulfur compounds, traces of metals, halide compounds, and nitrogen-containing chemicals will likely be lower in concentration in syngas derived from mixtures of coal and biomass (i.e., using an entrained-flow oxygen-blown gasifier) than solely from coal, other byproducts may be present in higher concentrations. The current project examines the impact of a number of potential byproducts of concern from the gasification of biomass process, including compounds containing alkali chemicals like the chlorides of sodium and potassium. In the second year, researchers from the University of Kentucky Center for Applied Energy Research (UK-CAER) continued the project by evaluating the sensitivity of a commercial iron-chromia high temperature water-gas shift catalyst (WGS) to a number of different compounds, including KHCO{sub 3}, NaHCO{sub 3}, HCl, HBr, HF, H{sub 2}S, NH{sub 3}, and a combination of H{sub 2}S and NH{sub 3}. Cobalt and iron-based Fischer-Tropsch synthesis (FT) catalysts were also subjected to a number of the same compounds in order to evaluate their sensitivities.

  8. Facile synthesis of Cu/Cu{sub x}O nanoarchitectures with adjustable phase composition for effective NO{sub x} gas sensor at room temperature

    SciTech Connect

    Yang, Lixue; Li, Li; Yang, Ying; Zhang, Guo; Gong, Lihong; Jing, Liqiang; Fu, Honggang; Shi, Keying

    2013-10-15

    Graphical abstract: The Cu/Cu{sub x}O nanoarchitectures with 30–70 nm hollow nanospheres reduced by 3 mmol NaBH{sub 4} exhibits excellent gas-sensing property to low-concentration NO{sub x} gas at room temperature. - Highlights: • The Cu/Cu{sub x}O nanoarchitectures with hollow nanospheres are successfully synthesized. • The method is used for preparing the with Cu/Cu{sub x}O adjustable phase composition. • The C3 sample exhibites excellent gas-sensing propertie to NO{sub x} at room temperation. • The Cu/Cu{sub x}O nanoarchitectures have significant for application of gas sensor. - Abstract: The Cu/Cu{sub x}O nanoarchitectures with 30–70 nm hollow nanospheres are successfully synthesized by a facile wet chemical method. The synthesized products have been studied by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermo gravimetric-differential scanning calorimetry (TG-DSC) analysis. The Cu/Cu{sub x}O sensors based on the nanoarchitectures are used to detect the NO{sub x} at room temperature. The results demonstrate that the obtained Cu/Cu{sub x}O nanoarchitectures reduced by 3 mmol NaBH{sub 4} exhibits excellent gas-sensing properties: low detection limit of 0.97 ppm, relatively high sensitivity, short response time, broad linear range and high selectivity. The reasons for gas-sensing activity enhancement on Cu/Cu{sub x}O nanoarchitectures are discussed. The Cu/Cu{sub x}O nanocrystalline with the hierarchical pores structure and tunable compositions have significant for application of gas sensor.

  9. Novel approaches to the production of higher alcohols from synthesis gas. Quarterly technical progress report No. 15, April 1, 1994--June 30, 1994

    SciTech Connect

    1996-05-01

    Under Task 2 four sets of methanol synthesis runs were conducted with BASF S3-86 ``low pressure``, Cu/ZnO methanol synthesis catalyst. The objectives were: (1) to reproduce the data obtained with this catalyst by researchers at Air Products and Chemicals, Inc., and; (2) to determine whether the previously-observed problem of catalyst poisoning by metal carbonyls had been eliminated. The catalyst poisoning problem appears to be resolved, although there is a need for additional data on the capacity of activated carbon for iron and nickel carbonyl adsorption. However, under apparently comparable conditions, the activity of the BASF S3-86 catalyst in the present experiments was lower than the activity measured at Air Products. The difference tentatively has been attributed to differences in the catalyst activation procedure.

  10. Synthesis of α-MoO3 nano-flakes by dry oxidation of RF sputtered Mo thin films and their application in gas sensing

    NASA Astrophysics Data System (ADS)

    Dwivedi, Priyanka; Dhanekar, Saakshi; Das, Samaresh

    2016-11-01

    Synthesis of orthorhombic (α) MoO3 nano-flakes by dry oxidation of RF sputtered Mo thin film is presented. The influence of Mo thickness variation, oxidation temperature and time on the crystallographic structure, surface morphology and roughness of MoO3 thin films was studied using SEM, AFM, XRD and Raman spectroscopy. A structural study shows that MoO3 is polycrystalline in nature with an α phase. It was noticed that oxidation temperature plays an important role in the formation of nano-flakes. The synthesis technique proposed is simple and suitable for large scale productions. The synthesis parameters were optimized for the fabrication of sensors. Chrome gold-based IDE (interdigitated electrodes) structures were patterned for the electrical detection of organic vapors. Sensors were exposed to wide range 5-100 ppm of organic vapors like ethanol, acetone, IPA (isopropanol alcohol) and water vapors. α-MoO3 nano-flakes have demonstrated selective sensing to acetone in the range of 10-100 ppm at 150 °C. The morphology of such nanostructures has potential in applications such as sensor devices due to their high surface area and thermal stability.

  11. Synthesis of flower-like Al doped ZnO microstructures by hydrothermal process and analysis of their gas sensing properties

    NASA Astrophysics Data System (ADS)

    Li, Zan; Qin, Wei; Zhao, Wenjie; Wu, Xiaohong

    2014-04-01

    Al-doped ZnO (AZO) powders with flower-like microstructures were successfully synthesized through a simple and efficient hydrothermal approach, and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy diffraction spectrum (EDS). All the samples presented high crystallinity with a hexagonal wurtzite structure. The heater gas sensors based on AZO were fabricated and investigation of gas sensing properties was conducted. The sensors showed high response values and reproducible response-recovery for 50-1800 ppm ethanol at 332°C, comparing with NH3, SO2, CO, and HCHO. The underlying mechanism was discussed.

  12. Effects of sol-gel synthesis on 5Fe-15Mn-40Zn-40Ti-O mixed oxide structure and its H2S removal efficiency from industrial gas streams.

    PubMed

    Polychronopoulou, Kyriaki; Efstathiou, Angelos M

    2009-06-15

    A novel Fe-Mn-Zn-Ti-O mixed metal oxide has been developed for efficient low-temperature (25-50 degrees C) removal of H2S from a gas mixture containing 600 ppm H2S, 25 vol% H2, 7.5 vol % CO2, and 1-3 vol% H2O that simulates typical conditions experienced at the outlet of a bioreactor loaded with sulfate metal reducing bacteria (SMRB) that converts toxic Cr6+ and As5+ present in ground and surface waters and soils into nontoxic elements. During the latter conversion H2S gas is produced and has to be treated. In the present work it is demonstrated for the first time that by using the sol-gel synthesis route at given experimental conditions (e.g., metal precursor salts, solvent system, and solution pH), optimum structural properties for the Fe-Mn-Zn-Ti-O solid can be obtained for maximization of H2S uptake. In particular, at 25 degrees C an H2S uptake (0.085 g H2S/g solid) larger by at least a factor of 3 compared to a commercial Ni-based H2S absorbent material was obtained.

  13. Advanced bioreactor systems for gaseous substrates: Conversion of synthesis gas to liquid fuels and removal of SO{sub X} and NO{sub X} from coal combustion gases

    SciTech Connect

    Selvaraj, P.T.; Kaufman, E.N.

    1996-06-01

    The purpose of this research program is the development and demonstration of a new generation of gaseous substrate based bioreactors for the production of liquid fuels from coal synthesis gas and the removal of NO{sub x} and SO{sub x} species from combustion flue gas. This R&D program is a joint effort between the staff of the Bioprocessing Research and Development Center (BRDC) of ORNL and the staff of Bioengineering Resources, Inc. (BRI) under a Cooperative Research and Development Agreement (CRADA). The Federal Coordinating Council for Science, Engineering, and Technology report entitled {open_quotes}Biotechnology for the 21st Century{close_quotes} and the recent Energy Policy Act of 1992 emphasizes research, development, and demonstration of the conversion of coal to gaseous and liquid fuels and the control of sulfur and nitrogen oxides in effluent streams. This R&D program presents an innovative approach to the use of bioprocessing concepts that will have utility in both of these identified areas.

  14. Mustard Gas: Its Pre-World War I History

    ERIC Educational Resources Information Center

    Duchovic, Ronald J.; Vilensky, Joel A.

    2007-01-01

    The Meyer-Clarke synthetic method was used in the German process for large scale production of mustard gas during World War I, which clearly shows the historical connection of synthesis of mustard gas.

  15. Structure and mechanism of the formation of core–shell nanoparticles obtained through a one-step gas-phase synthesis by electron beam evaporation

    PubMed Central

    Bardakhanov, Sergey P; Schreiber, Makoto; Bazarova, Dashima G; Romanov, Nikolai A; Baldanov, Boris B; Radnaev, Bair R; Syzrantsev, Viacheslav V

    2015-01-01

    Summary The structure of core–shell Cu@silica and Ag@Si nanoparticles obtained in one-step through evaporation of elemental precursors by a high-powered electron beam are investigated. The structure of the core and shell of the particles are investigated in order to elucidate their mechanisms of formation and factors affecting the synthesis. It is proposed that the formation of Cu@silica particles is mainly driven by surface tension differences between Cu and Si while the formation of Ag@Si particles is mainly driven by differences in the vapour concentration of the two components. PMID:25977857

  16. Structure and mechanism of the formation of core-shell nanoparticles obtained through a one-step gas-phase synthesis by electron beam evaporation.

    PubMed

    Nomoev, Andrey V; Bardakhanov, Sergey P; Schreiber, Makoto; Bazarova, Dashima G; Romanov, Nikolai A; Baldanov, Boris B; Radnaev, Bair R; Syzrantsev, Viacheslav V

    2015-01-01

    The structure of core-shell Cu@silica and Ag@Si nanoparticles obtained in one-step through evaporation of elemental precursors by a high-powered electron beam are investigated. The structure of the core and shell of the particles are investigated in order to elucidate their mechanisms of formation and factors affecting the synthesis. It is proposed that the formation of Cu@silica particles is mainly driven by surface tension differences between Cu and Si while the formation of Ag@Si particles is mainly driven by differences in the vapour concentration of the two components.

  17. Gas processing handbook

    SciTech Connect

    Not Available

    1982-04-01

    Brief details are given of processes including: BGC-Lurgi slagging gasification, COGAS, Exxon catalytic coal gasification, FW-Stoic 2-stage, GI two stage, HYGAS, Koppers-Totzek, Lurgi pressure gasification, Saarberg-Otto, Shell, Texaco, U-Gas, W-D.IGI, Wellman-Galusha, Westinghouse, and Winkler coal gasification processes; the Rectisol process; the Catacarb and the Benfield processes for removing CO/SUB/2, H/SUB/2s and COS from gases produced by the partial oxidation of coal; the selectamine DD, Selexol solvent, and Sulfinol gas cleaning processes; the sulphur-tolerant shift (SSK) process; and the Super-meth process for the production of high-Btu gas from synthesis gas.

  18. Gas and Gas Pains

    MedlinePlus

    ... your gas and bloating occur mainly after eating dairy products, it may be because your body isn' ... able to break down the sugar (lactose) in dairy foods. Other food intolerances, especially to gluten — a ...

  19. Effect of gas flow rates on the anatase-rutile transformation temperature of nanocrystalline TiO2 synthesised by chemical vapour synthesis.

    PubMed

    Ahmad, Md Imteyaz; Bhattacharya, S S; Fasel, Claudia; Hahn, Horst

    2009-09-01

    Of the three crystallographic allotropes of nanocrystalline titania (rutile, anatase and brookite), anatase exhibits the greatest potential for a variety of applications, especially in the area of catalysis and sensors. However, with rutile being thermodynamically the most stable phase, anatase tends to transform into rutile on heating to temperatures in the range of 500 degrees C to 700 degrees C. Efforts made to stabilize the anatase phase at higher temperatures by doping with metal oxides suffer from the problems of having a large amorphous content on synthesis as well as the formation of secondary impurity phases on doping. Recent studies have suggested that the as-synthesised phase composition, crystallite size, initial surface area and processing conditions greatly influence the anatase to rutile transformation temperature. In this study nanocrystalline titania was synthesised in the anatase form bya chemical vapour synthesis (CVS) method using titanium tetra iso-propoxide (TTIP) as a precursor under varying flow rates of oxygen and helium. The anatase to rutile transformation was studied using high temperature X-ray diffraction (HTXRD) and simultaneous thermogravimetric analysis (STA), followed by transmission electron microscopy (TEM). It was demonstrated that the anatase-rutile transformation temperatures were dependent on the oxygen to helium flow rate ratio during CVS and the results are presented and discussed.

  20. Facile synthesis of novel 3D nanoflower-like CuxO/multilayer graphene composites for room temperature NOx gas sensor application

    NASA Astrophysics Data System (ADS)

    Yang, Ying; Tian, Chungui; Wang, Jingchao; Sun, Li; Shi, Keying; Zhou, Wei; Fu, Honggang

    2014-06-01

    3D nanoflower-like CuxO/multilayer graphene composites (CuMGCs) have been successfully synthesized as a new type of room temperature NOx gas sensor. Firstly, the expanded graphite (EG) was activated by KOH and many moderate functional groups were generated; secondly, Cu(CH3COO)2 and CTAB underwent full infusion into the interlayers of activated EG (aEG) by means of a vacuum-assisted technique and then reacted with the functional groups of aEG accompanied by the exfoliation of aEG via reflux. Eventually, the 3D nanoflower consisting of 5-9 nm CuxO nanoparticles homogeneously grow in situ on aEG. The KOH activation of EG plays a key role in the uniform formation of CuMGCs. When being used as gas sensors for detection of NOx, the CuMGCs achieved a higher response at room temperature than that of the corresponding CuxO. In detail, the CuMGCs show a higher NOx gas sensing performance with low detection limit of 97 ppb, high gas response of 95.1% and short response time of 9.6 s to 97.0 ppm NOx at room temperature. Meanwhile, the CuMGC sensor presents a favorable linearity, good selectivity and stability. The enhancement of the sensing response is mainly attributed to the improved conductivity of the CuMGCs. A series of Mott-Schottky and EIS measurements demonstrated that the CuMGCs have much higher donor densities than CuxO and can easily capture and migrate electrons from the conduction band, resulting in the enhancement of electrical conductivity.3D nanoflower-like CuxO/multilayer graphene composites (CuMGCs) have been successfully synthesized as a new type of room temperature NOx gas sensor. Firstly, the expanded graphite (EG) was activated by KOH and many moderate functional groups were generated; secondly, Cu(CH3COO)2 and CTAB underwent full infusion into the interlayers of activated EG (aEG) by means of a vacuum-assisted technique and then reacted with the functional groups of aEG accompanied by the exfoliation of aEG via reflux. Eventually, the 3D nanoflower

  1. Gas-phase synthesis of nitrogen-doped TiO{sub 2} nanorods by microwave plasma torch at atmospheric pressure

    SciTech Connect

    Hong, Yong Cheol; Kim, Jong Hun; Bang, Chan Uk; Uhm, Han Sup

    2005-11-15

    Nitrogen (N)-doped titanium dioxide (TiO{sub 2}) nanorods were directly synthesized via decomposition of gas-phase titanium tetrachloride (TiCl{sub 4}) by an atmospheric microwave plasma torch. X-ray diffraction, field-emission scanning electron microscope, field-emission transmission electron microscope, and electron-energy-loss spectroscopy (EELS) have been employed to investigate fraction of the anatase and rutile phases, diameter and length, and chemical composition of the nanorods, respectively. The diameters of the nanorods are approximately 30-80 nm and the length is several micrometers. EELS data show that incorporation of N into the O site of TiO{sub 2} nanorods was enhanced in N{sub 2} gas by the microwave plasma torch. Also, a growth model of the rods was proposed on the basis of vapor-liquid-solid mechanism.

  2. Bench-scale demonstration of biological production of ethanol from coal synthesis gas. Quarterly report, April 1, 1994--June 30, 1994

    SciTech Connect

    Not Available

    1994-11-01

    CSTR studies are being performed to measure the effects of important design parameters such as dissolved CO concentration, pH, nutrients composition and concentration, gas retention time and liquid dilution rate on reactor performance. The results of these studies will yield valuable design information on the variables affecting the ethanol to acetate product ratio and culture stability. Ethanol concentrations of 13 g/L with ethanol to acetate product ratios of 13 mol/mol have been attained at an 18 min gas retention time without cell recycle. A comparison of product recovery techniques shows that direct distillation or solvent extraction, followed by pervaporation or azeotropic distillation, is most appropriate for ethanol recovery.

  3. Single-crystalline α-Fe2O3 oblique nanoparallelepipeds: high-yield synthesis, growth mechanism and structure enhanced gas-sensing properties.

    PubMed

    Li, Xuelian; Wei, Wenjing; Wang, Shaozhen; Kuai, Long; Geng, Baoyou

    2011-02-01

    In this paper, single-crystalline α-Fe2O3 oblique nanoparallelepipeds are fabricated in high yield via a facile surfactant-free hydrothermal method, which involves oriented aggregation and Ostwald ripening. The obtained nanocrystals have exposed facets of {012}, {01-4} and {-210} with a rhombohedral α-Fe2O3 structure. The gas sensors based on the as-synthesized α-Fe2O3 nanostructures exhibit high sensitivity, short recovery time, and good reproducibility in ethanol and acetone. The superiority of the gas-sensing properties of the obtained nanostructures should be attributed to the surface structure of the nanocrystals. The as-prepared α-Fe2O3 nanocrystals are significant for exploiting their other applications in the future.

  4. Flame Synthesis of Nanosized Cu-Ce-O, Ni-Ce-O, and Fe-Ce-O Catalysts for the Water-Gas Shift (WGS) Reaction

    DTIC Science & Technology

    2009-11-04

    transition-metal-doped ceria materials, which include coprecipitation (19-21), hydro- thermal (22), microemulsion (23-25), sol - gel (26, 27), and solution...examined toward water-gas shift (WGS) activity for fuel processing applications. The WGS activity of metal ceria catalysts decreases in the order Cu-Ce...Nonsto- ichiometric CeO2-x-based nanocrystalline catalysts have been shown to provide excellent activity for SO2 reduction by CO, CO oxidation

  5. Solid state synthesis of tin-doped ZnO at room temperature: characterization and its enhanced gas sensing and photocatalytic properties.

    PubMed

    Jia, Xiaohua; Fan, Huiqing; Afzaal, Mohammad; Wu, Xiangyang; O'Brien, Paul

    2011-10-15

    A room temperature solid-state reaction has been used to prepare crystalline tin-doped ZnO. Zinc nitrate hexahydrate, cetyltrimethyl ammonium bromide, stannic chloride pentahydrate and sodium hydroxide with proper ratios were ground together. As-synthesized samples were characterized by inductively coupled plasma analysis (ICP), scanning electron microscopy (SEM) and X-ray powder diffraction (XRD); The products were of different morphologies, well dispersed and exhibited good crystallinity, it is also found that the growth direction and morphology of ZnO depend on the amount of Sn doped, which is mainly caused by the difference in sizes between Zn and Sn atoms as well as the change of pH value. Moreover, gas sensing and photocatalytic properties of the obtained products were studied. The materials showed a high gas response to ethanol vapor, and the gas response can reach a maximum of R(a)/R(g) = 124. In addition, tin-doped ZnO materials exhibited improved photocatalytic performance toward methyl orange (MO) solution under a current density of 0.03 mg L(-1) comparison with undoped ZnO.

  6. MOF-templated synthesis of porous Co(3)O(4) concave nanocubes with high specific surface area and their gas sensing properties.

    PubMed

    Lü, Yinyun; Zhan, Wenwen; He, Yue; Wang, Yiting; Kong, Xiangjian; Kuang, Qin; Xie, Zhaoxiong; Zheng, Lansun

    2014-03-26

    Porous metal oxides nanomaterials with controlled morphology have received great attention because of their promising applications in catalysis, energy storage and conversion, gas sensing, etc. In this paper, porous Co3O4 concave nanocubes with extremely high specific surface area (120.9 m(2)·g(-1)) were synthesized simply by calcining Co-based metal-organic framework (Co-MOF, ZIF-67) templates at the optimized temperature (300 °C), and the formation mechanism of such highly porous structures as well as the influence of the calcination temperature are well explained by taking into account thermal behavior and intrinsic structural features of the Co-MOF precursors. The gas-sensing properties of the as-synthesized porous Co3O4 concave nanocubes were systematically tested towards volatile organic compounds including ethanol, acetone, toluene, and benzene. Experimental results reveal that the porous Co3O4 concave nanocubes present the highest sensitivity to ethanol with fast response/recovery time (< 10 s) and a low detection limit (at least 10 ppm). Such outstanding gas sensing performance of the porous Co3O4 concave nanocubes benefits from their high porosity, large specific surface area, and remarkable capabilities of surface-adsorbed oxygen.

  7. An activity, stability and selectivity comparison of propioin synthesis by thiamine diphosphate-dependent enzymes in a solid/gas bioreactor.

    PubMed

    Mikolajek, Renaud; Spiess, Antje C; Pohl, Martina; Lamare, Sylvain; Büchs, Jochen

    2007-06-18

    Enzymatic carboligation in a solid/gas bioreactor represents a new challenge in biotechnology. In this paper, the continuous gas-phase production of propioin from two propanal molecules by using thiamine diphosphate-dependent enzymes was studied. Two enzymes were used, namely benzaldehyde lyase (BAL) from Pseudomonas fluorescens and benzoylformate decarboxylase (BFD) from Pseudomonas putida. The enzymes are homologous and catalyze carboligase and carbolyase reactions in which no external cofactor regeneration is needed. The influence of water and substrate activity on the initial reaction rate and biocatalyst stability was investigated. An increase in water activity raised the initial reaction rates to the maximal values of 250 and 80 U g(-1) for BAL and BFD, respectively. The half-life showed the same trend with maximal values of 50 and 78 min for BAL and BFD, respectively. The increase in the half-life by increasing water activity was unexpected. It was also observed that BFD is more stable than BAL in the presence of the substrate propanal. Both enzymes showed substrate inhibition in the kinetic studies, and BAL was also deactivated during the reaction. Unexpectedly, the stereoselectivity of both enzymes (ee of 19 % for BAL and racemic mixture for BFD) was significantly impaired in the gas phase compared to the liquid phase.

  8. Metal-Organic Framework Templated Synthesis of Ultrasmall Catalyst Loaded ZnO/ZnCo2O4 Hollow Spheres for Enhanced Gas Sensing Properties

    PubMed Central

    Koo, Won-Tae; Choi, Seon-Jin; Jang, Ji-Soo; Kim, Il-Doo

    2017-01-01

    To achieve the rational design of nanostructures for superior gas sensors, the ultrasmall nanoparticles (NPs) loaded on ternary metal oxide (TMO) hollow spheres (HS) were synthesized by using the polystyrene (PS) sphere template and bimetallic metal-organic framework (BM-MOFs) mold. The zinc and cobalt based zeolite imidazole frameworks (BM-ZIFs) encapsulating ultrasmall Pd NPs (2–3 nm) were assembled on PS spheres at room temperature. After calcination at 450 °C, these nanoscale Pd particles were effectively infiltrated on the surface of ZnO/ZnCo2O4 HSs. In addition, the heterojunctions of Pd-ZnO, Pd-ZnCo2O4, and ZnO-ZnCo2O4 were formed on each phase. The synthesized Pd-ZnO/ZnCo2O4 HSs exhibited extremely high selectivity toward acetone gas with notable sensitivity (S = 69% to 5 ppm at 250 °C). The results demonstrate that MOF driven ultrasmall catalyst loaded TMO HSs were highly effective platform for high performance chemical gas sensors. PMID:28327599

  9. Controlled synthesis of hollow Cu₂-x Te nanocrystals based on the Kirkendall effect and their enhanced CO gas-sensing properties.

    PubMed

    Xiao, Guanjun; Zeng, Yi; Jiang, Yueyue; Ning, Jiajia; Zheng, Weitao; Liu, Bingbing; Chen, Xiaodong; Zou, Guangtian; Zou, Bo

    2013-03-11

    This paper develops a facile solution-based method to synthesize hollow Cu2-x Te nanocrystals (NCs) with tunable interior volume based on the Kirkendall effect. Transmission electron microscopy images and time-dependent absorption spectra reveal the temporal growth process from solid copper nanoparticles to hollow Cu2-x Te NCs. Furthermore, the as-prepared hollow Cu2-x Te NCs show enhanced sensitivity for the detection of carbon monoxide (CO), which is often referred to as the "silent killer". The response and recovery time of the as-prepared sensor for the detection of 100 ppm CO gas are estimated to be about 21 and 100 s, respectively, which are sufficient to render it a promising candidate for effective CO gas-sensing applications. Such enhanced performance is achieved owing to the small grain size and large specific area of the hollow nanostructures. Therefore, the obtained hollow NCs based on the Kirkendall effect may have the potential as new functional blocks for high-performance gas sensors.

  10. Metal-Organic Framework Templated Synthesis of Ultrasmall Catalyst Loaded ZnO/ZnCo2O4 Hollow Spheres for Enhanced Gas Sensing Properties

    NASA Astrophysics Data System (ADS)

    Koo, Won-Tae; Choi, Seon-Jin; Jang, Ji-Soo; Kim, Il-Doo

    2017-03-01

    To achieve the rational design of nanostructures for superior gas sensors, the ultrasmall nanoparticles (NPs) loaded on ternary metal oxide (TMO) hollow spheres (HS) were synthesized by using the polystyrene (PS) sphere template and bimetallic metal-organic framework (BM-MOFs) mold. The zinc and cobalt based zeolite imidazole frameworks (BM-ZIFs) encapsulating ultrasmall Pd NPs (2–3 nm) were assembled on PS spheres at room temperature. After calcination at 450 °C, these nanoscale Pd particles were effectively infiltrated on the surface of ZnO/ZnCo2O4 HSs. In addition, the heterojunctions of Pd-ZnO, Pd-ZnCo2O4, and ZnO-ZnCo2O4 were formed on each phase. The synthesized Pd-ZnO/ZnCo2O4 HSs exhibited extremely high selectivity toward acetone gas with notable sensitivity (S = 69% to 5 ppm at 250 °C). The results demonstrate that MOF driven ultrasmall catalyst loaded TMO HSs were highly effective platform for high performance chemical gas sensors.

  11. Model Catalysis of Ammonia Synthesis ad Iron-Water Interfaces - ASum Frequency Generation Vibrational Spectroscopic Study of Solid-GasInterfaces and Anion Photoelectron Spectroscopic Study of Selected Anionclusters

    SciTech Connect

    Ferguson, Michael James

    2005-01-01

    The ammonia synthesis reaction has been studied using single crystal model catalysis combined with sum frequency generation (SFG) vibrational spectroscopy. The adsorption of gases N2, H2, O2 and NH3 that play a role in ammonia synthesis have been studied on the Fe(111) crystal surface by sum frequency generation vibrational spectroscopy using an integrated Ultra-High Vacuum (UHV)/high-pressure system. SFG spectra are presented for the dissociation intermediates, NH2 (~3325 cm-1) and NH (~3235 cm-1) under high pressure of ammonia or equilibrium concentrations of reactants and products on Fe(111) surfaces. Special attention was paid to understand how potassium promotion of the iron catalyst affects the intermediates of ammonia synthesis. An Fe(111) surface promoted with 0.2 monolayers of potassium red shifts the vibrational frequencies of the reactive surface intermediates, NH and NH2, providing evidence for weakened the nitrogen-hydrogen bonds relative to clean Fe(111). Spectral features of these surface intermediates persisted to higher temperatures for promoted iron surfaces than for clean Fe(111) surfaces implying that nitrogen-iron bonds are stronger for the promoted surface. The ratio of the NH to NH2 signal changed for promoted surfaces in the presence of equilibrium concentrations of reactants and products. The order of adding oxygen and potassium to promoted surfaces does not alter the spectra indicating that ammonia induces surface reconstruction of the catalyst to produce the same surface morphology. When oxygen is co-adsorbed with nitrogen, hydrogen, ammonia or potassium on Fe(111), a relative phase shift of the spectra occurs as compared to the presence of adsorbates on clean iron surfaces. Water adsorption on iron was also probed using SFG vibrational spectroscopy. For both H2O and D2O, the only spectral feature was in the range of

  12. Palladium(II)‐Catalysed Aminocarbonylation of Terminal Alkynes for the Synthesis of 2‐Ynamides: Addressing the Challenges of Solvents and Gas Mixtures

    PubMed Central

    Hughes, N. Louise; Brown, Clare L.; Irwin, Andrew A.; Cao, Qun

    2017-01-01

    Abstract 2‐Ynamides can be synthesised through PdII catalysed oxidative carbonylation, utilising low catalyst loadings. A variety of alkynes and amines can be used to afford 2‐ynamides in high yields, whilst overcoming the drawbacks associated with previous oxidative methods, which rely on dangerous solvents and gas mixtures. The use of [NBu4]I allows the utilisation of the industrially recommended solvent ethyl acetate. O2 can be used as the terminal oxidant, and the catalyst can operate under safer conditions with low O2 concentrations. PMID:27906507

  13. Silver(I)-Catalyzed Synthesis of β-Oxopropylcarbamates from Propargylic Alcohols and CO2 Surrogate: A Gas-Free Process.

    PubMed

    Song, Qing-Wen; Zhou, Zhi-Hua; Yin, Hong; He, Liang-Nian

    2015-12-07

    The utilization of carbon dioxide poses major challenges owing to its high thermodynamic stability and kinetic inertness. To circumvent these problems, a simple reaction system is reported comprising ammonium carbamates as carbon dioxide surrogates, propargylic alcohols, and a silver(I) catalyst, for the effective conversion of a wide range of alcohols and secondary amines into the corresponding β-oxopropylcarbamates. A key feature of this strategy includes quantitative use of a carbon resource with high product yields under gas-free and mild reaction conditions. Notably, this catalytic protocol also works well for the carboxylative cyclization of propargylic amines and carbon dioxide surrogates to afford 2-oxazolidinones.

  14. Palladium(II)-Catalysed Aminocarbonylation of Terminal Alkynes for the Synthesis of 2-Ynamides: Addressing the Challenges of Solvents and Gas Mixtures.

    PubMed

    Hughes, N Louise; Brown, Clare L; Irwin, Andrew A; Cao, Qun; Muldoon, Mark J

    2017-02-22

    2-Ynamides can be synthesised through Pd(II) catalysed oxidative carbonylation, utilising low catalyst loadings. A variety of alkynes and amines can be used to afford 2-ynamides in high yields, whilst overcoming the drawbacks associated with previous oxidative methods, which rely on dangerous solvents and gas mixtures. The use of [NBu4 ]I allows the utilisation of the industrially recommended solvent ethyl acetate. O2 can be used as the terminal oxidant, and the catalyst can operate under safer conditions with low O2 concentrations.

  15. Phosphorus-containing polymers from THPS. IV: Synthesis and properties of phosphorus-containing polybenzoxazines as a green route for recycling toxic phosphine (PH3) tail gas.

    PubMed

    Tan, Zhi-Wei; Sun, Jian; Wu, Cheng-Yan; Qiu, Jin-Jun; Liu, Cheng-Mei

    2017-01-15

    A convenient route to convert the highly toxic phosphine (PH3) tail gas into high-performance polybenzoxazines was first described in this paper. Two aliphatic polyamines, namely tris(aminomethyl)phosphine oxide and bis(aminomethyl)phenylphosphine oxide, were synthesized from tetrakis(hydroxymethyl)phosphonium sulfate (THPS), a green derivative of PH3 tail gas. And then two novel phosphorus-containing benzoxazine monomers, tris(3,4-dihydro-2H-1,3-benzoxazin-3-yl-methyl)phosphine oxide (TBOz) and benzylbis(3,4-dihydro-2H-1,3-benzoxazin-3-yl-methyl) phosphine oxide (BBOz) were prepared by three-steps procedure. FT-IR and DSC technologies were adopted to study the thermal-initiated polymerization behaviors of two benzoxazine monomers. Thermal properties of these crosslinked polymers were studied by TGA and DMA. The results display that the polybenzoxazines (PTBOz and PBBOz) exhibite good thermal stabilities and high glass transition temperatures. The char yield of polybanzoxazine is high as 47% and indiactes that phosphorus-containing polybenzoxazines show high fire-retardancy. The surface free energies of the PTBOz and PBBOz are 37.1 and 40.4mJm(-2) by Owens two-liquid method. The dielectric properties of the PTBOz and PBBOz remaine near constant in the experimental frequency range.

  16. The synthesis of porous Co{sub 3}O{sub 4} micro cuboid structures by solvothermal approach and investigation of its gas sensing properties and catalytic activity

    SciTech Connect

    Jamil, Saba; Jing, Xiaoyan; Wang, Jun; Li, Songnan; Liu, Jingyuan; Zhang, Milin

    2013-11-15

    Graphical abstract: - Highlights: • Micro cuboid Co{sub 3}O{sub 4} particle prepared by solvothermal method. • Study of morphology of synthesized cuboids before and after calcinations. • Investigation of formation mechanism of porous Co{sub 3}O{sub 4} from cuboid CoCO{sub 3}. • Investigation of gas sensing properties of porous Co{sub 3}O{sub 4}. • Study of catalytic activity of product. - Abstract: The cobalt carbonate cuboids are prepared by adopting a simple solvothermal approach by using diethylene glycol and water in specific ratio as solvent. The prepared cobalt carbonate is subjected to different instrumentation to investigate its morphology and other properties. It is clear from the scanning electron microscopy (SEM) and transmission electron microscopy (TEM) that the product is distinct cuboid in shape with a size of approximately 3 μm from each face of the cube. Each particle of cuboid cobalt carbonate seems to comprise of layer by layer assembly of unit cells that consequently leads to a cuboid geometry. The cuboid cobalt carbonate was calcined at 700 °C in a furnace under argon atmosphere that decompose cobalt carbonate into porous Co{sub 3}O{sub 4} with the loosely packed arrangement of nano architectures. The gas sensing properties and catalytic activity of porous cuboids Co{sub 3}O{sub 4} are also investigated.

  17. Synthesis of ultrasmooth nanostructured diamond films by microwave plasma chemical vapor deposition using a He/H2/CH4/N2 gas mixture

    PubMed Central

    Chowdhury, S.; Hillman, Damon A.; Catledge, Shane A.; Konovalov, Valery V.; Vohra, Yogesh K.

    2008-01-01

    Ultrasmooth nanostructured diamond (USND) films were synthesized on Ti–6Al–4V medical grade substrates by adding helium in H2/CH4/N2 plasma and changing the N2/CH4 gas flow from 0 to 0.6. We were able to deposit diamond films as smooth as 6 nm (root-mean-square), as measured by an atomic force microscopy (AFM) scan area of 2 μm2. Grain size was 4–5 nm at 71% He in (H2 + He) and N2/CH4 gas flow ratio of 0.4 without deteriorating the hardness (~50–60 GPa). The characterization of the films was performed with AFM, scanning electron microscopy, x-ray diffraction (XRD), Raman spectroscopy, and nanoindentation techniques. XRD and Raman results showed the nanocrystalline nature of the diamond films. The plasma species during deposition were monitored by optical emission spectroscopy. With increasing N2/CH4 feedgas ratio (CH4 was fixed) in He/H2/CH4/N2 plasma, a substantial increase of CN radical (normalized by Balmer Hα line) was observed along with a drop in surface roughness up to a critical N2/CH4 ratio of 0.4. The CN radical concentration in the plasma was thus correlated to the formation of ultrasmooth nanostructured diamond films. PMID:18946515

  18. Biomolecule-assisted synthesis and gas-sensing properties of porous nanosheet-based corundum In{sub 2}O{sub 3} microflowers

    SciTech Connect

    Zhang Wenhui; Zhang Weide

    2012-02-15

    Porous nanosheet-based corundum In{sub 2}O{sub 3} microflowers were fabricated by one-pot hydrothermal treatment of D-fructose and In(NO{sub 3}){sub 3} mixture using urea as a precipitating agent followed by calcination. The products were characterized by X-ray diffraction, scanning and transmission electron microscopy. The effects of D-fructose and urea on the fabrication of nanosheet-based corundum In{sub 2}O{sub 3} microflowers were investigated and a possible mechanism is proposed to explain the formation of the hierarchical nanostructures. The gas sensor based on the In{sub 2}O{sub 3} microflowers exhibits excellent sensing properties for the detection of formaldehyde. - Graphical abstract: Nanosheets-based corundum In{sub 2}O{sub 3} microflowers were fabricated by one-pot hydrothermal treatment of D-fructose/In(NO{sub 3}){sub 3} mixture followed by calcination, which show high performance for formaldehyde sensing. Highlights: Black-Right-Pointing-Pointer Preparation of porous nanosheet-based corundum In{sub 2}O{sub 3} microflowers. Black-Right-Pointing-Pointer Morphology and phase control of In{sub 2}O{sub 3}. Black-Right-Pointing-Pointer Gas sensor based on the In{sub 2}O{sub 3} microflowers exhibits excellent sensing properties for the detection of formaldehyde.

  19. Modeling mass transfer in solid oxide fuel cell anode: II. H2/CO co-oxidation and surface diffusion in synthesis-gas operation

    NASA Astrophysics Data System (ADS)

    Bao, Cheng; Jiang, Zeyi; Zhang, Xinxin

    2016-08-01

    Following the previous work on comparing performance of Fickian, Stefan-Maxwell and dusty-gas model for mass transfer in single fuel system, this article is focused on the electrochemistry and transport in the anode of solid oxide fuel cell using H2sbnd H2Osbnd COsbnd CO2sbnd N2 hybrid fuel. Under the standard framework of the dusty-gas model combined with the Butler-Volmer equation, it carries out a macroscopic area-specific modeling work. More specifically, two variables of hydrogen current fraction and enhancement factor are well defined and solved for the electrochemical co-oxidation of H2 and CO, and the diffusion equivalent circuit model is introduced to describe more comprehensively the resistance of mass transfer including molecular/Knudsen diffusion and surface diffusion. The model has been validated well in full region of Vsbnd I performance of an experimental anode-supported button cell. An approximate analytical solution of the hydrogen current fraction is also presented for explicit computation. Comparison between the results by different approaches for the effective diffusivity shows the importance of right mass-transfer modeling.

  20. Low cost hydrogen/novel membrane technology for hydrogen separation from synthesis gas, Phase 1. [Poly(etherimide) and poly(ether-ester-amide) membranes

    SciTech Connect

    Not Available

    1986-01-01

    During the last quarter several high performance membranes for the separation of hydrogen from nitrogen, carbon monoxide, hydrogen sulfide and carbon dioxide. The heat-resistant resin poly(etherimide) has been selected as the polymer with the most outstanding properties for the separation of hydrogen from nitrogen and carbon monoxide. Flat sheet and hollow fiber poly(etherimide) membranes have been prepared and evaluated with pure gases and gas mixtures at elevated pressures and temperatures. Multilayer composite poly(ether-ester-amide) membranes were also developed. These membranes are useful for the separation of carbon dioxide and hydrogen sulfide hydrogen. They have very high selectivities and extremely high normalized carbon dioxide and hydrogen sulfide fluxes. Separation of carbon dioxide/hydrogen streams is a key problem in hydrogen production from coal. The development of the two membranes now gives us two approaches to separate these gas streams, depending on the stream's composition. If the stream contains small quantities of hydrogen, the hydrogen- permeable poly(etherimide) membrane would be used to produce a hydrogen-enriched permeate. If the stream contains small quantities of carbon dioxide or hydrogen sulfide, the poly(ether-ester-amide) membrane would be used to produce a carbon dioxide/hydrogen sulfide-free, hydrogen-enriched residue stream. 6 fig., 4 tabs.

  1. Low cost hydrogen/novel membrane technology for hydrogen separation from synthesis gas, Phase 1. Quarterly technical progress report for the period ending December 31, 1986

    SciTech Connect

    Not Available

    1986-12-31

    During the last quarter several high performance membranes for the separation of hydrogen from nitrogen, carbon monoxide, hydrogen sulfide and carbon dioxide. The heat-resistant resin poly(etherimide) has been selected as the polymer with the most outstanding properties for the separation of hydrogen from nitrogen and carbon monoxide. Flat sheet and hollow fiber poly(etherimide) membranes have been prepared and evaluated with pure gases and gas mixtures at elevated pressures and temperatures. Multilayer composite poly(ether-ester-amide) membranes were also developed. These membranes are useful for the separation of carbon dioxide and hydrogen sulfide hydrogen. They have very high selectivities and extremely high normalized carbon dioxide and hydrogen sulfide fluxes. Separation of carbon dioxide/hydrogen streams is a key problem in hydrogen production from coal. The development of the two membranes now gives us two approaches to separate these gas streams, depending on the stream`s composition. If the stream contains small quantities of hydrogen, the hydrogen- permeable poly(etherimide) membrane would be used to produce a hydrogen-enriched permeate. If the stream contains small quantities of carbon dioxide or hydrogen sulfide, the poly(ether-ester-amide) membrane would be used to produce a carbon dioxide/hydrogen sulfide-free, hydrogen-enriched residue stream. 6 fig., 4 tabs.

  2. Ultrasound assisted synthesis of PANI/ZnMoO4 nanocomposite for simultaneous improvement in anticorrosion, physico-chemical properties and its application in gas sensing.

    PubMed

    Bhanvase, B A; Darda, N S; Veerkar, N C; Shende, A S; Satpute, S R; Sonawane, S H

    2015-05-01

    Ultrasound assisted in-situ semi-batch emulsion polymerization has been used for the preparation of polyaniline (PANI) and PANI/ZnMoO4 nanocomposite with different loading of ZnMoO4 (ZM) nanoparticles. ZM nanoparticles were functionalized using Myristic acid (MA) for better compatibility with PANI. The cavitational effects induced due to ultrasonic irradiations have been shown significant enhancement in the dispersion of functionalized ZM nanoparticles into the PANI during ultrasound assisted in-situ emulsion polymerization process. TEM images of PANI/ZM nanocomposite particles give the direct evidence of fine dispersion and encapsulation of MA treated ZM nanoparticles in PANI matrix. The presence of ZM nanoparticles in PANI/ZM nanocomposite shows significant improvement in the mechanical (cross-cut adhesion), thermal, anticorrosion and sensing properties of PANI/ZM nanocomposite/alkyd coatings over PANI/alkyd and neat alkyd resin coating. Fine and uniform dispersion of ZM nanoparticles in PANI matrix using this novel synthesis method (PANI (p-type)/ZM (n-type) hetero-junction) improves LPG sensing ability and minimizes response time to sense LPG significantly compared with neat PANI.

  3. A New Process for Maleic Anhydride Synthesis from a Renewable Building Block: The Gas-Phase Oxidehydration of Bio-1-butanol.

    PubMed

    Pavarelli, Giulia; Velasquez Ochoa, Juliana; Caldarelli, Aurora; Puzzo, Francesco; Cavani, Fabrizio; Dubois, Jean-Luc

    2015-07-08

    We investigated the synthesis of maleic anhydride by oxidehydration of a bio-alcohol, 1-butanol, as a possible alternative to the classical process of n-butane oxidation. A vanadyl pyrophosphate catalyst was used to explore the one-pot reaction, which involved two sequential steps: 1) 1-butanol dehydration to 1-butene, catalysed by acid sites, and 2) the oxidation of butenes to maleic anhydride, catalysed by redox sites. A non-negligible amount of phthalic anhydride was also formed. The effect of different experimental parameters was investigated with chemically sourced 1-butanol, and the results were then confirmed by using genuinely bio-sourced 1-butanol. In the case of bio-1-butanol, however, the purity of the product remarkably affected the yield of maleic anhydride. It was found that the reaction mechanism includes the oxidation of butenes to crotonaldehyde and the oxidation of the latter to either furan or maleic acid, both of which are transformed to produce maleic anhydride.

  4. Conversion of glycerol to hydrogen rich gas.

    PubMed

    Tran, Nguyen H; Kannangara, G S Kamali

    2013-12-21

    Presently there is a glut of glycerol as the by-product of biofuel production and it will grow as production increases. The conundrum is how we can consume this material and convert it into a more useful product. One potential route is to reform glycerol to hydrogen rich gas including synthesis gas (CO + H2) and hydrogen. However, there is recent literature on various reforming techniques which may have a bearing on the efficiency of such a process. Hence in this review reforming of glycerol at room temperature (normally photo-catalytic), catalysis at moderate and high temperature and a non-catalytic pyrolysis process are presented. The high temperature processes allow the generation of synthesis gas with the hydrogen to carbon monoxide ratios being suitable for synthesis of dimethyl ether, methanol and for the Fischer-Tropsch process using established catalysts. Efficient conversion of synthesis gas to hydrogen involves additional catalysts that assist the water gas shift reaction, or involves in situ capture of carbon dioxide and hydrogen. Reforming at reduced temperatures including photo-reforming offers the opportunity of producing synthesis gas or hydrogen using single catalysts. Together, these processes will assist in overcoming the worldwide glut of glycerol, increasing the competitiveness of the biofuel production and reducing our dependency on the fossil based, hydrogen rich gas.

  5. Two-stage process for conversion of synthesis gas to high quality transportation fuels. Quarterly report, April 1-June 30, 1984

    SciTech Connect

    Kuo, J.C.W.

    1984-08-01

    This quarter, the sixth run of the two stage bench-scale unit (BSU) was completed and the seventh started. Many of the new features of the pilot plant were successfully tested, and low methane + ethane yields were achieved in both runs. Run CT-256-7 is the first to use an orifice-type feed-gas distributor. The 10.2 cm ID tall hot-flow column was shaken down, while further scoping hydrodynamic studies were performed in our short hot-flow bubble-columns. An improved chromatographic technique was developed for analyzing reactor-wax and some results are reported here. Proprietary wax-upgrading studies are reported in the Mobil Proprietary Appendix. 3 refs., 10 figs., 4 tabs.

  6. The synthesis of multifunctional porous honey comb-like La2O3 thin film for supercapacitor and gas sensor applications.

    PubMed

    Yadav, A A; Lokhande, A C; Pujari, R B; Kim, J H; Lokhande, C D

    2016-12-15

    The porous honey comb-like La2O3 thin films have been synthesized using one step spray pyrolysis method. The influence of sprayed solution quantity on properties of La2O3 thin films is studied using X-ray diffraction, Fourier transform spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, optical absorption and Brunauer-Emmett-Teller techniques. Morphology of La2O3 electrode is controlled with sprayed solution quantity. The supercapacitive properties of La2O3 thin film electrode are investigated using cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance techniques. The La2O3 film electrode exhibited the specific capacitance of the 166Fg(-1) with 85% stability for the 3000 cycles. The La2O3 film electrode exhibited sensitivity of 68 at 523K for 500ppm CO2 gas concentration. The possible CO2 sensing mechanism is discussed.

  7. Rotational spectroscopy of ClZnCH3 (X1A1): Gas-phase synthesis and characterization of a monomeric Grignard-type reagent

    NASA Astrophysics Data System (ADS)

    Min, J.; Bucchino, M. P.; Kilchenstein, K. M.; Ziurys, L. M.

    2016-02-01

    The pure rotational spectrum of the organozinc halide, ClZnCH3 (X1A1), has been measured using Fourier-transform microwave (FTMW) and millimeter-wave direct-absorption methods in the frequency range 10-296 GHz. This work is the first study of ClZnCH3 by gas-phase spectroscopy. The molecule was created in a DC discharge from the reaction of zinc vapor, produced either by a Broida-type oven or by laser ablation, with chloromethane in what appears to be a metal insertion process. Rotational and chlorine quadrupole constants were determined for three zinc isotopologues. The Znsbnd Cl bond was found to be partly ionic and significantly shorter than in EtZnCl.

  8. Single Step Bi-reforming and Oxidative Bi-reforming of Methane (Natural Gas) with Steam and Carbon Dioxide to Metgas (CO-2H2) for Methanol Synthesis: Self-Sufficient Effective and Exclusive Oxygenation of Methane to Methanol with Oxygen.

    PubMed

    Olah, George A; Goeppert, Alain; Czaun, Miklos; Mathew, Thomas; May, Robert B; Prakash, G K Surya

    2015-07-15

    Catalysts based on suitable metal oxide supports, such as NiO/MgO and CoO/MgO, were shown to be active for single step bi-reforming, the combined steam and dry reforming of methane or natural gas with H2O and CO2 exclusively to metgas (CO-2H2) for efficient methanol synthesis. Reactions were carried out in a tubular flow reactor under pressures up to 42 bar at 830-910 °C. Using a CH4 to steam to CO2 ratio of ∼3:2:1 in the gas feed, the H2/CO ratio of 2:1 was achieved, which is desired for subsequent methanol synthesis. The needed 2/1 steam/CO2 feed ratio together with the reaction heat for the endothermic bi-reforming can be conveniently obtained by the complete combustion of a quarter part of the overall used methane (natural gas) with oxygen of the air (oxidative bi-reforming). Complete combustion of a part of methane followed by bi-reforming leads to the production of metgas (H2/CO in 2:1 mol ratio) for self-sufficient exclusive methanol synthesis. The long sought after but elusive efficient and selective oxygenation of methane to methanol is thus achieved in an effective and economic way without any oxidation byproduct formation according to CH4 + 1/2O2 → CH3OH.

  9. A new 3D Co(II)–organic framework with acylamide-containing tetracarboxylate ligand: Solvothermal synthesis, crystal structure, gas adsorption and magnetic property

    SciTech Connect

    Zhang, Qingfu Zhang, Haina; Geng, Aijing; Wang, Suna; Zhang, Chong

    2014-04-01

    A new cobalt(II)–organic framework, [Co{sub 2}(L)(py){sub 2}(DMSO)]{sub n}• 0.5nDMF• 2nDMSO (1) [H{sub 4}L=5,5'-((naphthalene-2,6-dicarbonyl)bis(azanediyl))diisophthalic acid, py=pyridine, DMSO=dimethyl sulfoxide, DMF=N,N-dimethylformamide], has been solvothermally synthesized and characterized by elemental analysis, IR, TGA, PXRD and single-crystal X-ray crystallography. The structural analysis reveals that complex 1 is a 3D framework built from nanosized acylamide-containing tetracarboxylate ligands (L{sup 4−}) and dinuclear [Co{sub 2}(CO{sub 2}){sub 4}] secondary building units (SBUs), exhibiting a uninodal (4,4)-connected crb topology with the Schläfli symbol of (4• 6{sup 5}). The desolvated complex (1a) displays higher adsorption capability for CO{sub 2} than N{sub 2}, which may be due to the relatively strong binding affinity between the CO{sub 2} molecules and acylamide groups in the framework. The magnetic investigation shows that the dominant antiferromagnetic interaction is observed in complex 1. - Graphical abstract: A new 3D Co(II)–organic framework with nanosized acylamide-containing tetracarboxylate ligand was solvothermally synthesized and structurally characterized, its thermal stability, gas adsorption and magnetic property were studied. - Highlights: • A new 3D Co(II)–organic framework with nanosized acylamide-containing tetracarboxylate ligand has been solvothermally synthesized and characterized. • Complex 1 exhibits a uninodal (4,4)-connected crb topology. • The thermal stability, gas adsorption and magnetic property were studied.

  10. Controllable synthesis of recyclable core-shell γ-Fe2O3@SnO2 hollow nanoparticles with enhanced photocatalytic and gas sensing properties.

    PubMed

    Zhang, Shaofeng; Ren, Feng; Wu, Wei; Zhou, Juan; Xiao, Xiangheng; Sun, Lingling; Liu, Ying; Jiang, Changzhong

    2013-06-07

    Composite materials containing different components with well-defined structures may cooperatively enhance their performance and extend their applications. In this work, core-shell γ-Fe2O3@SnO2 hollow nanoparticles (NPs) were synthesized by a low-cost and environmentally friendly seed-mediated hydrothermal method. Firstly, the γ-Fe2O3 hollow NPs were synthesized by a template-free method. Then they were used as the cores for the growth of SnO2 shells. The thickness of the shell can be simply tailored by controlling the reaction time. Various techniques, including SEM, XRD, TEM and HRTEM, were employed to investigate the morphology, structure and formation process of the special core-shell hollow structures. The combination of magnetic semiconductor (γ-Fe2O3) and wide band-gap semiconductor (SnO2) endowed them with great potential to be used as recyclable photocatalysts. Experiments on photo-degradation of Rhodamin B (RhB) dye in the presence of the samples showed that the hybrid structures possessed higher photocatalytic activities than the monomer structures of SnO2 and γ-Fe2O3 materials indicating a strong coupling enhancement effect between the wide and narrow band-gap semiconductors. Moreover, the gas sensing tests of the γ-Fe2O3@SnO2 hollow NPs revealed that the samples exhibited fast response and recovery rates, which enable them to be promising materials for gas sensors.

  11. Synthetic gas production for methanol--current and future trends

    SciTech Connect

    Camps, J.A.; Turnbull, D.McG.

    1980-01-01

    Methanol is one of the most easily made organic compounds and is synthesized from a gaseous mixture of carbon monoxide and hydrogen, called ''synthesis gas''. Thus the first step in the manufacture of methanol constitutes the production of synthesis gas. This paper describes various methods of producing this gas from natural gas and naphtha through reforming, coal gasification and wood gasification. Chemical plants for synthesis of methanol on industrial scales are described. Markets for methanol are reviewed, with particular attention to its use as an additive to gasoline. (Refs. 4).

  12. Environmental controls of energy and trace gas exchanges at the water-air interface: Global synthesis of eddy fluxes over inland waters

    NASA Astrophysics Data System (ADS)

    Golub, M.; Desai, A. R.; Bohrer, G.; Blanken, P.; Deshmukh, C. S.; Franz, D.; Guérin, F.; Heiskanen, J. J.; Jammet, M.; Jonsson, A.; Karlsson, J.; Koebsch, F.; Liu, H.; Lohila, A.; Lundin, E.; Mammarella, I.; Rutgersson, A.; Sachs, T.; Serça, D.; Spence, C.; Strachan, I. B.; Vesala, T.; Weyhenmeyer, G. A.; Xiao, W.; Glatzel, S.

    2015-12-01

    Current estimates of energy and trace gases from inland waters often rely on limited point in time measurements, therefore, short time variation of fluxes and mechanism controlling the fluxes are particularly understudied. Here we present the results of a global synthesis of eddy fluxes from 29 globally distributed aquatic sites. The objective of this study was to quantify the magnitudes and variation of energy and CO2 fluxes and investigate their responses to environmental controls across half-hourly to monthly time scales. The coupled observations of in-lake physical and biogeochemical parameters with meteorology and eddy covariance fluxes were analyzed using decomposed correlation and wavelength coherence analysis to quantify the critical time scales that are associated with variation of energy and CO2 fluxes, and related drivers. The rates of fluxes were synthesized according to time scale, climate, and water body type. The diurnal cycles of both energy and CO2 fluxes variation were attributed to wind speed, solar radiation cycle, vapor pressure deficit, temperature gradients at water-air interface, and metabolism. Weekly time scales of variations were correlated with synoptic weather patterns. The monthly sums of energy fluxes showed a latitudinal gradient with the maxima observed in mid-latitude waterbodies. We found an inconsistent latitudinal pattern of monthly CO2 fluxes. Instead, we found correlation with proxies of lake productivity suggesting lake-specific characteristics play an important role in controlling flux magnitudes and variation. The results presented here highlight the importance of quantifying short-term variation of energy and trace gases fluxes towards improving the understanding of the water and carbon cycles and linked ecological processes.

  13. SnO2 quantum dots and quantum wires: controllable synthesis, self-assembled 2D architectures, and gas-sensing properties.

    PubMed

    Xu, Xiangxing; Zhuang, Jing; Wang, Xun

    2008-09-17

    SnO2 quantum dots (QDs) and ultrathin nanowires (NWs) with diameters of approximately 0.5-2.5 and approximately 1.5-4.5 nm, respectively, were controllably synthesized in a simple solution system. They are supposed to be ideal models for studying the continuous evolution of the quantum-confinement effect in SnO2 1D --> 0D systems. The observed transition from strong to weak quantum confinement in SnO2 QDs and ultrathin NWs is interpreted through the use of the Brus effective-mass approximation and the Nosaka finite-depth well model. Photoluminescence properties that were coinfluenced by size effects, defects (oxygen vacancies), and surface capping are discussed in detail. With the SnO2 QDs as building blocks, various 2D porous structures with ordered hexagonal, distorted hexagonal, and square patterns were prepared on silicon-wafer surfaces and exhibited optical features of 2D photonic crystals and enhanced gas sensitivity.

  14. Optical properties of palladium nanoparticles under exposure of hydrogen and inert gas prepared by dewetting synthesis of thin-sputtered layers

    NASA Astrophysics Data System (ADS)

    Kracker, Michael; Worsch, Christian; Rüssel, Christian

    2013-04-01

    Thin layers of palladium with a thickness of 5 nm were sputtered on fused silica substrates. Subsequently, the coated glasses were annealed at a temperature of 900 °C for 1 h. This resulted in the formation of small and well-separated palladium nanoparticles with diameters in the range from 20 to 200 nm on the glass surface. The existence of a palladium oxide layer can be detected using optical absorption spectroscopy. Purging with hydrogen leads to an irreversible change in the optical spectra due to the reduction of PdO to metallic palladium. Changing the gas atmosphere from hydrogen to argon leads to significant reversible changes in the optical properties of the particle layer. Based on Mie theory and the respective dielectric functions, the spectra were calculated using the real particle size distribution, weighted dispersions relation to adapt the geometrical conditions and complex dielectric functions of palladium and palladium hydride. A good agreement with measured spectra was found and the dependency of the surrounding media can be explained.

  15. Synthesis of polychlorinated terphenyl mixtures and gas chromatography with mass spectrometry data of tetra- to octachlorinated ortho-, meta-, and para-terphenyls.

    PubMed

    Vetter, Walter; Kirres, Jochen; Bendig, Paul

    2012-11-09

    Polychlorinated terphenyls (PCTs) are a class of polyhalogenated compounds previously used in similar applications as polychlorinated biphenyls (PCBs). According to present knowledge all industrial production was closed in the 1970s. The total PCT manufacture reached about 5% of the production of PCBs. Unlike the PCBs, PCTs have been scarcely analyzed in environmental samples mostly due to analytical difficulties. PCTs were synthesized by the chlorination of technical terphenyl which consists of ortho-, meta- and para-terphenyls. This procedure led to very complex mixtures of polychlorinated compounds whose composition, especially with regard to the terphenyl backbones, remained unknown. Here we report the individual chlorination of the three terphenyl backbones to mixtures of Tetra- to OctaCTs, respectively. The average degree of chlorination of the ortho-, meta- and para-PCTs ranged from 6.8 to 7.4. These products were analyzed by gas chromatography with mass spectrometry in electron ionization (GC/EI-MS) and electron capture negative ion (GC/ECNI-MS) modes. The elution order of isomers was ortho-PCTs≪meta-PCTs

  16. Gas-phase reactions of molecular oxygen with uranyl(V) anionic complexes-synthesis and characterization of new superoxides of uranyl(VI).

    PubMed

    Lucena, Ana F; Carretas, José M; Marçalo, Joaquim; Michelini, Maria C; Gong, Yu; Gibson, John K

    2015-04-16

    Gas-phase complexes of uranyl(V) ligated to anions X(-) (X = F, Cl, Br, I, OH, NO3, ClO4, HCO2, CH3CO2, CF3CO2, CH3COS, NCS, N3), [UO2X2](-), were produced by electrospray ionization and reacted with O2 in a quadrupole ion trap mass spectrometer to form uranyl(VI) anionic complexes, [UO2X2(O2)](-), comprising a superoxo ligand. The comparative rates for the oxidation reactions were measured, ranging from relatively fast [UO2(OH)2](-) to slow [UO2I2](-). The reaction rates of [UO2X2](-) ions containing polyatomic ligands were significantly faster than those containing the monatomic halogens, which can be attributed to the greater number of vibrational degrees of freedom in the polyatomic ligands to dissipate the energy of the initial O2-association complexes. The effect of the basicity of the X(-) ligands was also apparent in the relative rates for O2 addition, with a general correlation between increasing ligand basicity and O2-addition efficiency for polyatomic ligands. Collision-induced dissociation of the superoxo complexes showed in all cases loss of O2 to form the [UO2X2](-) anions, indicating weaker binding of the O2(-) ligand compared to the X(-) ligands. Density functional theory computations of the structures and energetics of selected species are in accord with the experimental observations.

  17. Gas storage using fullerene based adsorbents

    NASA Technical Reports Server (NTRS)

    Loutfy, Raouf O. (Inventor); Lu, Xiao-Chun (Inventor); Li, Weijiong (Inventor); Mikhael, Michael G. (Inventor)

    2000-01-01

    This invention is directed to the synthesis of high bulk density high gas absorption capacity adsorbents for gas storage applications. Specifically, this invention is concerned with novel gas absorbents with high gravimetric and volumetric gas adsorption capacities which are made from fullerene-based materials. By pressing fullerene powder into pellet form using a conventional press, then polymerizing it by subjecting the fullerene to high temperature and high inert gas pressure, the resulting fullerene-based materials have high bulk densities and high gas adsorption capacities. By pre-chemical modification or post-polymerization activation processes, the gas adsorption capacities of the fullerene-based adsorbents can be further enhanced. These materials are suitable for low pressure gas storage applications, such as oxygen storage for home oxygen therapy uses or on-board vehicle natural gas storage. They are also suitable for storing gases and vapors such as hydrogen, nitrogen, carbon dioxide, and water vapor.

  18. Reviews and syntheses: Greenhouse gas emissions in natural and agricultural lands in sub-Saharan Africa: synthesis of available data and suggestions for further studies

    NASA Astrophysics Data System (ADS)

    Kim, D.-G.; Thomas, A. D.; Pelster, D.; Rosenstock, T. S.; Sanz-Cobena, A.

    2015-10-01

    This paper summarizes currently available data on greenhouse gas (GHG) emissions from African natural and agricultural lands, outlines the knowledge gaps and suggests future directions and strategies for GHG emission studies. GHG emission data were collected from 73 studies conducted in 22 countries in sub-Saharan Africa (SSA). Soil GHG emissions from African natural terrestrial systems ranged from 3.3 to 57.0 Mg carbon dioxide (CO2) ha-1 yr-1, -4.8 to 3.5 kg methane (CH4) ha-1 yr-1 and -0.1 to 13.7 kg nitrous oxide (N2O) ha-1 yr-1. Soil physical and chemical properties, rewetting, vegetation type, forest management and land-use changes were all found to be important factors affecting soil GHG emissions. Greenhouse gas emissions from African aquatic systems ranged from 5.7 to 232.0 Mg CO2 ha-1 yr-1, -26.3 to 2741.9 kg CH4 ha-1 yr-1 and 0.2 to 3.5 kg N2O ha-1 yr-1 and were strongly affected by discharge. Soil GHG emissions from African croplands ranged from 1.7 to 141.2 Mg CO2 ha-1 yr-1, -1.3 to 66.7 kg CH4 ha-1 yr-1and 0.05 to 112.0 kg N2O ha-1 yr-1 and the N2O emission factor (EF) ranged from 0.01 to 4.1 %. Incorporation of crop residues or manure with inorganic fertilizers resulted in significant changes in GHG emissions but these were different for CO2 and N2O. Soil GHG emissions in vegetable gardens ranged from 73.3 to 132.0 Mg CO2 ha-1 yr-1 and 53.4 to 177.6 kg N2O ha-1 yr-1 and N2O EFs ranged from 3 to 4 %. Soil CO2 and N2O emissions from agroforestry were 38.6 Mg CO2 ha-1 yr-1 and 0.2 to 26.7 kg N2O ha-1 yr-1, respectively. Improving fallow with nitrogen (N)-fixing trees increased CO2 and N2O emissions compared to conventional croplands and type and quality of plant residue is likely to be an important control factor affecting N2O emissions. Throughout agricultural lands, N2O emissions slowly increased with N inputs below 150 kg N ha-1 yr-1 and increased exponentially with N application rates up to 300 kg N ha-1 yr-1. The lowest yield-scaled N2O emissions

  19. Gas phase synthesis, structure and unimolecular reactivity of silver iodide cluster cations, Ag(n)I(m)(+) (n = 2-5, 0 < m < n).

    PubMed

    Khairallah, George N; O'Hair, Richard A J

    2008-06-14

    Multistage mass spectrometry (MS(n)) experiments reveal that gas phase silver iodide cluster cations, Ag(n)I(m)(+), are readily built up in a stepwise fashion via ion-molecule reactions between mass selected silver (Ag(3)(+) and Ag(5)(+)) or silver hydride (Ag(2)H(+) and Ag(4)H(+)) cluster cations and allyl iodide, in contrast to their reactions with methyl iodide, which solely result in ligation of the clusters. The stoichiometries of these clusters range from 1 < or = n < or = 5 and 1 < or = m < or = 4, indicating the formation of several new subvalent silver iodide clusters. Collision induced dissociation (CID) experiments were carried out on each of these clusters to shed some light on their possible structures. The products arising from CID of the Ag(n)I(m)(+) clusters are highly dependent on the stoichiometry of the cluster. Thus the odd-electron clusters Ag(4)I(2)(+) and Ag(5)I(+) fragment via loss of a silver atom. In contrast, the even-electron cluster ions all fragment via loss of AgI. In addition, Ag(2)I(2) loss is observed for the Ag(4)I(3)(+) and Ag(5)I(2)(+) clusters, while loss of Ag(3)I(3) occurs for the stoichiometric Ag(5)I(4)(+) cluster. DFT calculations were carried out on these Ag(n)I(m)(+) clusters as well as the neutrals associated with the ion-molecule and CID reactions. A range of different isomeric structures were calculated and their structures are described. A noteworthy aspect is that ligation of these silver clusters by I can have a profound effect on the geometry of the silver cluster. For example, D(3h) Ag(3)(+) becomes C(2v) Ag(3)I(+), which in turn becomes C(2h) Ag(3)I(2)(+). Finally, the DFT predicted thermochemistry supports the different types of reaction channels observed in the ion-molecule reactions and CID experiments.

  20. Novel ball-type four dithioerythritol bridged metallophthalocyanines and their water-soluble derivatives: Synthesis and characterization, and electrochemical, electrocatalytic, electrical and gas sensing properties.

    PubMed

    Ceyhan, Tanju; Altındal, Ahmet; Ozkaya, Ali Rıza; Salih, Bekir; Bekaroğlu, Ozer

    2010-11-07

    region the correlated barrier hopping model is the dominant mechanism. The sensing properties of the films for CO(2) gas were also investigated.

  1. Greenhouse gas emissions from natural ecosystems and agricultural lands in sub-Saharan Africa: synthesis of available data and suggestions for further research

    NASA Astrophysics Data System (ADS)

    Kim, Dong-Gill; Thomas, Andrew D.; Pelster, David; Rosenstock, Todd S.; Sanz-Cobena, Alberto

    2016-08-01

    This paper summarizes currently available data on greenhouse gas (GHG) emissions from African natural ecosystems and agricultural lands. The available data are used to synthesize current understanding of the drivers of change in GHG emissions, outline the knowledge gaps, and suggest future directions and strategies for GHG emission research. GHG emission data were collected from 75 studies conducted in 22 countries (n = 244) in sub-Saharan Africa (SSA). Carbon dioxide (CO2) emissions were by far the largest contributor to GHG emissions and global warming potential (GWP) in SSA natural terrestrial systems. CO2 emissions ranged from 3.3 to 57.0 Mg CO2 ha-1 yr-1, methane (CH4) emissions ranged from -4.8 to 3.5 kg ha-1 yr-1 (-0.16 to 0.12 Mg CO2 equivalent (eq.) ha-1 yr-1), and nitrous oxide (N2O) emissions ranged from -0.1 to 13.7 kg ha-1 yr-1 (-0.03 to 4.1 Mg CO2 eq. ha-1 yr-1). Soil physical and chemical properties, rewetting, vegetation type, forest management, and land-use changes were all found to be important factors affecting soil GHG emissions from natural terrestrial systems. In aquatic systems, CO2 was the largest contributor to total GHG emissions, ranging from 5.7 to 232.0 Mg CO2 ha-1 yr-1, followed by -26.3 to 2741.9 kg CH4 ha-1 yr-1 (-0.89 to 93.2 Mg CO2 eq. ha-1 yr-1) and 0.2 to 3.5 kg N2O ha-1 yr-1 (0.06 to 1.0 Mg CO2 eq. ha-1 yr-1). Rates of all GHG emissions from aquatic systems were affected by type, location, hydrological characteristics, and water quality. In croplands, soil GHG emissions were also dominated by CO2, ranging from 1.7 to 141.2 Mg CO2 ha-1 yr-1, with -1.3 to 66.7 kg CH4 ha-1 yr-1 (-0.04 to 2.3 Mg CO2 eq. ha-1 yr-1) and 0.05 to 112.0 kg N2O ha-1 yr-1 (0.015 to 33.4 Mg CO2 eq. ha-1 yr-1). N2O emission factors (EFs) ranged from 0.01 to 4.1 %. Incorporation of crop residues or manure with inorganic fertilizers invariably resulted in significant changes in GHG emissions, but results were inconsistent as the magnitude and direction of

  2. Gas separating

    DOEpatents

    Gollan, Arye Z.

    1990-12-25

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing.

  3. Gas separating

    DOEpatents

    Gollan, Arye

    1988-01-01

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing.

  4. GAS BEARING

    DOEpatents

    Skarstrom, C.W.

    1960-09-01

    A gas lubricated bearing for a rotating shaft is described. The assembly comprises a stationary collar having an annular member resiliently supported thereon. The collar and annular member are provided with cooperating gas passages arranged for admission of pressurized gas which supports and lubricates a bearing block fixed to the rotatable shaft. The resilient means for the annular member support the latter against movement away from the bearing block when the assembly is in operation.

  5. Gas vesicles.

    PubMed Central

    Walsby, A E

    1994-01-01

    The gas vesicle is a hollow structure made of protein. It usually has the form of a cylindrical tube closed by conical end caps. Gas vesicles occur in five phyla of the Bacteria and two groups of the Archaea, but they are mostly restricted to planktonic microorganisms, in which they provide buoyancy. By regulating their relative gas vesicle content aquatic microbes are able to perform vertical migrations. In slowly growing organisms such movements are made more efficiently than by swimming with flagella. The gas vesicle is impermeable to liquid water, but it is highly permeable to gases and is normally filled with air. It is a rigid structure of low compressibility, but it collapses flat under a certain critical pressure and buoyancy is then lost. Gas vesicles in different organisms vary in width, from 45 to > 200 nm; in accordance with engineering principles the narrower ones are stronger (have higher critical pressures) than wide ones, but they contain less gas space per wall volume and are therefore less efficient at providing buoyancy. A survey of gas-vacuolate cyanobacteria reveals that there has been natural selection for gas vesicles of the maximum width permitted by the pressure encountered in the natural environment, which is mainly determined by cell turgor pressure and water depth. Gas vesicle width is genetically determined, perhaps through the amino acid sequence of one of the constituent proteins. Up to 14 genes have been implicated in gas vesicle production, but so far the products of only two have been shown to be present in the gas vesicle: GvpA makes the ribs that form the structure, and GvpC binds to the outside of the ribs and stiffens the structure against collapse. The evolution of the gas vesicle is discussed in relation to the homologies of these proteins. Images PMID:8177173

  6. Gas separating

    DOEpatents

    Gollan, A.

    1988-03-29

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.

  7. Gas Chromatograph.

    DTIC Science & Technology

    Patents, * Gas chromotography , *Hydrocarbons, *Carbon monoxide, *Carbon dioxide, *Water, Field equipment, Portable equipment, Sensitivity, Halogenated hydrocarbons, Test methods, Gases, Liquids, Purity

  8. Gas magnetometer

    SciTech Connect

    Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert

    2016-05-03

    Measurement of a precessional rate of a gas, such as an alkali gas, in a magnetic field is made by promoting a non-uniform precession of the gas in which substantially no net magnetic field affects the gas during a majority of the precession cycle. This allows sensitive gases that would be subject to spin-exchange collision de-phasing to be effectively used for extremely sensitive measurements in the presence of an environmental magnetic field such as the Earth's magnetic field.

  9. Gas separating

    DOEpatents

    Gollan, A.Z.

    1990-12-25

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.

  10. Biogas as a fuel for solid oxide fuel cells and synthesis gas production: effects of ceria-doping and hydrogen sulfide on the performance of nickel-based anode materials.

    PubMed

    Laycock, Christian J; Staniforth, John Z; Ormerod, R Mark

    2011-05-28

    Numerous investigations have been carried out into the conversion of biogas into synthesis gas (a mixture of H(2) + CO) over Ni/YSZ anode cermet catalysts. Biogas is a variable mixture of gases consisting predominantly of methane and carbon dioxide (usually in a 2 : 1 ratio, but variable with source), with other constituents including sulfur-containing gases such as hydrogen sulfide, which can cause sulfur poisoning of nickel catalysts. The effect of temperature on carbon deposition and sulfur poisoning of 90 : 10 mol% Ni/YSZ under biogas conversion conditions has been investigated by carrying out a series of catalytic reactions of methane-rich (2 : 1) CH(4)/CO(2) mixtures in the absence and presence of H(2)S over the temperature range 750-1000 °C. The effect of ceria-doping on carbon dioxide reforming, carbon deposition and sulfur tolerance has also been investigated by carrying out a similar series of reactions over ceria-doped Ni/YSZ. Ceria was doped at 5 mol% of the nickel content to give an anode catalyst composition of 85.5 : 4.5 : 10 mol% Ni/CeO(2)/YSZ. Reactions were followed using quadrupolar mass spectrometry (QMS) and the amount of carbon deposition was analysed by subjecting the reacted catalyst samples to a post-reaction temperature programmed oxidation (TPO). On undoped Ni/YSZ, carbon deposition occurred predominantly through thermal decomposition of methane. Ceria-doping significantly suppressed methane decomposition and at high temperatures simultaneously promoted the reverse Boudouard reaction, significantly lowering carbon deposition. Sulfur poisoning of Ni/YSZ occurred in two phases, the first of which caused the most activity loss and was accelerated on increasing the reaction temperature, while the second phase had greater stability and became more favourable with increasing reaction temperature. Adding H(2)S significantly inhibited methane decomposition, resulting in much less carbon deposition. Ceria-doping significantly increased the sulfur

  11. Gas Chromatography.

    ERIC Educational Resources Information Center

    Karasek, Francis W.; And Others

    1984-01-01

    This review covers fundamental developments in gas chromatography during 1982 and 1983. Literature is considered under these headings: columns; liguid phases; solid supports; sorption processes and solvents; open tubular column gas chromatography; instrumentation; high-resolution columns and applications; other techniques; qualitative and…

  12. Highly Adsorptive, MOF-Functionalized Nonwoven Fiber Mats for Hazardous Gas Capture Enabled by Atomic Layer Deposition

    DTIC Science & Technology

    2014-03-20

    and toxic gas sensing. Here, we demonstrate a new synthesis route for growing MOFs on fibrous materials that achieves high MOF loadings, large surface...new applications in gas adsorption, membrane separation, catalysis, and toxic gas sensing. Here, we demonstrate a new synthesis route for growing...sizes and adjustable internal functionality. [ 4 ] MOF synthesis usually follows wet solvo- thermal batch methods, producing pow- ders that require

  13. A sustainable catalytic pyrrole synthesis

    NASA Astrophysics Data System (ADS)

    Michlik, Stefan; Kempe, Rhett

    2013-02-01

    The pyrrole heterocycle is a prominent chemical motif and is found widely in natural products, drugs, catalysts and advanced materials. Here we introduce a sustainable iridium-catalysed pyrrole synthesis in which secondary alcohols and amino alcohols are deoxygenated and linked selectively via the formation of C-N and C-C bonds. Two equivalents of hydrogen gas are eliminated in the course of the reaction, and alcohols based entirely on renewable resources can be used as starting materials. The catalytic synthesis protocol tolerates a large variety of functional groups, which includes olefins, chlorides, bromides, organometallic moieties, amines and hydroxyl groups. We have developed a catalyst that operates efficiently under mild conditions.

  14. Gas Chromatography.

    ERIC Educational Resources Information Center

    Cram, Stuart P.; And Others

    1980-01-01

    Selects fundamental developments in theory, methodology, and instrumentation in gas chromatography (GC). A special section reviews GC in the People's Republic of China. Over 1,000 references are cited. (CS)

  15. Volcanic Gas

    MedlinePlus

    ... Hazards Tephra/Ash Lava Flows Lahars Volcanic Gas Climate Change Pyroclastic Flows Volcanic Landslides Preparedness Volcano Hazard Zones ... Please see our discussion of volcanic gases and climate change for additional information. Hydrogen sulfide (H 2 S) is ...

  16. Gas exchange

    MedlinePlus Videos and Cool Tools

    ... during exhalation. Gas exchange is the delivery of oxygen from the lungs to the bloodstream, and the ... share a membrane with the capillaries in which oxygen and carbon dioxide move freely between the respiratory ...

  17. Gas Jets

    NASA Technical Reports Server (NTRS)

    Chaplygin, S.

    1944-01-01

    A brief summary of the contents of this paper is presented here. In part I the differential equations of the problem of a gas flow in two dimensions is derived and the particular integrals by which the problem on jets is solved are given. Use is made of the same independent variables as Molenbroek used, but it is found to be more suitable to consider other functions. The stream function and velocity potential corresponding to the problem are given in the form of series. The investigation on the convergence of these series in connection with certain properties of the functions entering them forms the subject of part II. In part III the problem of the outflow of a gas from an infinite vessel with plane walls is solved. In part IV the impact of a gas jet on a plate is considered and the limiting case where the jet expands to infinity changing into a gas flow is taken up in more detail. This also solved the equivalent problem of the resistance of a gaseous medium to the motion of a plate. Finally, in part V, an approximate method is presented that permits a simpler solution of the problem of jet flows in the case where the velocities of the gas (velocities of the particles in the gas) are not very large.

  18. Combustion synthesis continuous flow reactor

    DOEpatents

    Maupin, Gary D.; Chick, Lawrence A.; Kurosky, Randal P.

    1998-01-01

    The present invention is a reactor for combustion synthesis of inorganic powders. The reactor includes a reaction vessel having a length and a first end and a second end. The reaction vessel further has a solution inlet and a carrier gas inlet. The reactor further has a heater for heating both the solution and the carrier gas. In a preferred embodiment, the reaction vessel is heated and the solution is in contact with the heated reaction vessel. It is further preferred that the reaction vessel be cylindrical and that the carrier gas is introduced tangentially into the reaction vessel so that the solution flows helically along the interior wall of the reaction vessel. As the solution evaporates and combustion produces inorganic material powder, the carrier gas entrains the powder and carries it out of the reactor.

  19. Combustion synthesis continuous flow reactor

    DOEpatents

    Maupin, G.D.; Chick, L.A.; Kurosky, R.P.

    1998-01-06

    The present invention is a reactor for combustion synthesis of inorganic powders. The reactor includes a reaction vessel having a length and a first end and a second end. The reaction vessel further has a solution inlet and a carrier gas inlet. The reactor further has a heater for heating both the solution and the carrier gas. In a preferred embodiment, the reaction vessel is heated and the solution is in contact with the heated reaction vessel. It is further preferred that the reaction vessel be cylindrical and that the carrier gas is introduced tangentially into the reaction vessel so that the solution flows helically along the interior wall of the reaction vessel. As the solution evaporates and combustion produces inorganic material powder, the carrier gas entrains the powder and carries it out of the reactor. 10 figs.

  20. Combustion synthesis of advanced composite materials

    NASA Technical Reports Server (NTRS)

    Moore, John J.

    1993-01-01

    Self-propagating high temperature (combustion) synthesis (SHS), has been investigated as a means of producing both dense and expanded (foamed) ceramic and ceramic-metal composites, ceramic powders and whiskers. Several model exothermic combustion synthesis reactions were used to establish the importance of certain reaction parameters, e.g., stoichiometry, green density, combustion mode, particle size, etc. on the control of the synthesis reaction, product morphology and properties. The use of an in situ liquid infiltration technique and the effect of varying the reactants and their stoichiometry to provide a range of reactant and product species i.e., solids, liquids and gases, with varying physical properties e.g., volatility and thermal conductivity, on the microstructure and morphology of synthesized composite materials is discussed. Conducting the combustion synthesis reaction in a reactive gas environment to take advantage of the synergistic effects of combustion synthesis and vapor phase transport is also examined.

  1. Gas Analyzer

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A miniature gas chromatograph, a system which separates a gaseous mixture into its components and measures the concentration of the individual gases, was designed for the Viking Lander. The technology was further developed under National Institute for Occupational Safety and Health (NIOSH) and funded by Ames Research Center/Stanford as a toxic gas leak detection device. Three researchers on the project later formed Microsensor Technology, Inc. to commercialize the product. It is a battery-powered system consisting of a sensing wand connected to a computerized analyzer. Marketed as the Michromonitor 500, it has a wide range of applications.

  2. IGNITION IMPROVEMENT OF LEAN NATURAL GAS MIXTURES

    SciTech Connect

    Jason M. Keith

    2005-02-01

    This report describes work performed during a thirty month project which involves the production of dimethyl ether (DME) on-site for use as an ignition-improving additive in a compression-ignition natural gas engine. A single cylinder spark ignition engine was converted to compression ignition operation. The engine was then fully instrumented with a cylinder pressure transducer, crank shaft position sensor, airflow meter, natural gas mass flow sensor, and an exhaust temperature sensor. Finally, the engine was interfaced with a control system for pilot injection of DME. The engine testing is currently in progress. In addition, a one-pass process to form DME from natural gas was simulated with chemical processing software. Natural gas is reformed to synthesis gas (a mixture of hydrogen and carbon monoxide), converted into methanol, and finally to DME in three steps. Of additional benefit to the internal combustion engine, the offgas from the pilot process can be mixed with the main natural gas charge and is expected to improve engine performance. Furthermore, a one-pass pilot facility was constructed to produce 3.7 liters/hour (0.98 gallons/hour) DME from methanol in order to characterize the effluent DME solution and determine suitability for engine use. Successful production of DME led to an economic estimate of completing a full natural gas-to-DME pilot process. Additional experimental work in constructing a synthesis gas to methanol reactor is in progress. The overall recommendation from this work is that natural gas to DME is not a suitable pathway to improved natural gas engine performance. The major reasons are difficulties in handling DME for pilot injection and the large capital costs associated with DME production from natural gas.

  3. Development of iron-aluminide hot-gas filters

    SciTech Connect

    Tortorelli, P.F.; Wright, I.G.; Judkins, R.R.

    1996-06-01

    Removal of particles from hot synthesis gas produced by coal gasification is vital to the success of these systems. In Integrated [Coal] Gasification Combined Cycle systems, the synthesis gas is the fuel for gas turbines. To avoid damage to turbine components, it is necessary that particles be removed from the fuel gas prior to combustion and introduction into the turbine. Reliability and durability of the hot-gas filtering devices used to remove the particles is, of course, of special importance. Hot-gas filter materials include both ceramics and metals. Numerous considerations must be made in selecting materials for these filters. Constituents in the hot gases may potentially degrade the properties and performance of the filters to the point that they are ineffective in removing the particles. Very significant efforts have been made by DOE and others to develop effective hot-particle filters and, although improvements have been made, alternative materials and structures are still needed.

  4. Gas sensor

    SciTech Connect

    Schmid, Andreas K.; Mascaraque, Arantzazu; Santos, Benito; de la Figuera, Juan

    2014-09-09

    A gas sensor is described which incorporates a sensor stack comprising a first film layer of a ferromagnetic material, a spacer layer, and a second film layer of the ferromagnetic material. The first film layer is fabricated so that it exhibits a dependence of its magnetic anisotropy direction on the presence of a gas, That is, the orientation of the easy axis of magnetization will flip from out-of-plane to in-plane when the gas to be detected is present in sufficient concentration. By monitoring the change in resistance of the sensor stack when the orientation of the first layer's magnetization changes, and correlating that change with temperature one can determine both the identity and relative concentration of the detected gas. In one embodiment the stack sensor comprises a top ferromagnetic layer two mono layers thick of cobalt deposited upon a spacer layer of ruthenium, which in turn has a second layer of cobalt disposed on its other side, this second cobalt layer in contact with a programmable heater chip.

  5. Sol-Gel Thin Films for Plasmonic Gas Sensors.

    PubMed

    Della Gaspera, Enrico; Martucci, Alessandro

    2015-07-13

    Plasmonic gas sensors are optical sensors that use localized surface plasmons or extended surface plasmons as transducing platform. Surface plasmons are very sensitive to dielectric variations of the environment or to electron exchange, and these effects have been exploited for the realization of sensitive gas sensors. In this paper, we review our research work of the last few years on the synthesis and the gas sensing properties of sol-gel based nanomaterials for plasmonic sensors.

  6. Sol-Gel Thin Films for Plasmonic Gas Sensors

    PubMed Central

    Della Gaspera, Enrico; Martucci, Alessandro

    2015-01-01

    Plasmonic gas sensors are optical sensors that use localized surface plasmons or extended surface plasmons as transducing platform. Surface plasmons are very sensitive to dielectric variations of the environment or to electron exchange, and these effects have been exploited for the realization of sensitive gas sensors. In this paper, we review our research work of the last few years on the synthesis and the gas sensing properties of sol-gel based nanomaterials for plasmonic sensors. PMID:26184216

  7. CATALYST ACTIVITY MAINTENANCE FOR THE LIQUID PHASE SYNTHESIS GAS-TO-DIMETHYL ETHER PROCESS PART II: DEVELOPMENT OF ALUMINUM PHOSPHATE AS THE DEHYDRATION CATALYST FOR THE SINGLE-STEP LIQUID PHASE SYNGAS-TO-DME PROCESS

    SciTech Connect

    Xiang-Dong Peng

    2002-05-01

    At the heart of the single-step liquid phase syngas-to-DME process (LPDME{trademark}) is a catalyst system that can be active as well as stable. In the Alternative Fuels I program, a dual-catalyst system containing a Cu-based commercial methanol synthesis catalyst (BASF S3-86) and a commercial dehydration material ({gamma}-alumina) was demonstrated. It provided the productivity and selectivity expected from the LPDME process. However, the catalyst system deactivated too rapidly to warrant a viable commercial process [1]. The mechanistic investigation in the early part of the DOE's Alternative Fuels II program revealed that the accelerated catalyst deactivation under LPDME conditions is due to detrimental interaction between the methanol synthesis catalyst and methanol dehydration catalyst [2,3]. The interaction was attributed to migration of Cu- and/or Zn-containing species from the synthesis catalyst to the dehydration catalyst. Identification of a dehydration catalyst that did not lead to this detrimental interaction while retaining adequate dehydration activity was elusive. Twenty-nine different dehydration materials were tested, but none showed the desired performance [2]. The search came to a turning point when aluminum phosphate was tested. This amorphous material is prepared by precipitating a solution containing Al(NO{sub 3}){sub 3} and H{sub 3}PO{sub 4} with NH{sub 4}OH, followed by washing, drying and calcination. The aluminum phosphate catalyst has adequate dehydration activity and good stability. It can co-exist with the Cu-based methanol synthesis catalyst without negatively affecting the latter catalyst's stability. This report documents the details of the development of this catalyst. These include initial leads, efforts in improving activity and stability, investigation and development of the best preparation parameters and procedures, mechanistic understanding and resulting preparation guidelines, and the accomplishments of this work.

  8. GAS SEAL

    DOEpatents

    Monson, H.; Hutter, E.

    1961-07-11

    A seal is described for a cover closing an opening in the top of a pressure vessel that may house a nuclear reactor. The seal comprises a U-shaped trough formed on the pressure vessel around the opening therein, a mass of metal in the trough, and an edge flange on the cover extending loosely into the trough and dipping into the metal mass. The lower portion of the metal mass is kept melted, and the upper portion, solid. The solid pontion of the metal mass prevents pressure surges in the vessel from expelling the liquid portion of the metal mass from the trough; the liquld portion, thus held in place by the solid portion, does not allow gas to go through, and so gas cannot escape through shrinkage holes in the solid portion.

  9. Volcanic gas

    USGS Publications Warehouse

    McGee, Kenneth A.; Gerlach, Terrance M.

    1995-01-01

    In Roman mythology, Vulcan, the god of fire, was said to have made tools and weapons for the other gods in his workshop at Olympus. Throughout history, volcanoes have frequently been identified with Vulcan and other mythological figures. Scientists now know that the “smoke" from volcanoes, once attributed by poets to be from Vulcan’s forge, is actually volcanic gas naturally released from both active and many inactive volcanoes. The molten rock, or magma, that lies beneath volcanoes and fuels eruptions, contains abundant gases that are released to the surface before, during, and after eruptions. These gases range from relatively benign low-temperature steam to thick hot clouds of choking sulfurous fume jetting from the earth. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide. Other volcanic gases are hydrogen sulfide, hydrochloric acid, hydrogen, carbon monoxide, hydrofluoric acid, and other trace gases and volatile metals. The concentrations of these gas species can vary considerably from one volcano to the next.

  10. Gas chromatography.

    PubMed

    Eiceman, G A; Hill, H H; Gardea-Torresdey, J

    1998-06-15

    This review of the fundamental developments in gas chromatography (GC) includes articles published from 1996 and 1997 and an occasional citation prior to 1996. The literature was reviewed principally using CA Selects for Gas Chromatography from Chemical Abstracts Service, and some significant articles from late 1997 may be missing from the review. In addition, the online SciSearch Database (Institute for Scientific Information) capability was used to abstract review articles or books. As with the prior recent reviews, emphasis has been given to the identification and discussion of selected developments, rather than a presentation of a comprehensive literature search, now available widely through computer-based resources. During the last two years, several themes emerged from a review of the literature. Multidimensional gas chromatography has undergone transformation encompassing a broad range of activity, including attempts to establish methods using chromatographic principles rather than a totally empirical approach. Another trend noted was a comparatively large effort in chromatographic theory through modeling efforts; these presumably became resurgent with inexpensive and powerful computing tools. Finally, an impressive level of activity was noted through the themes highlighted in this review, and this was particularly true with detectors and field instruments.

  11. Method for hot gas conditioning

    DOEpatents

    Paisley, Mark A.

    1996-02-27

    A method for cracking and shifting a synthesis gas by the steps of providing a catalyst consisting essentially of alumina in a reaction zone; contacting the catalyst with a substantially oxygen free mixture of gases comprising water vapor and hydrocarbons having one or more carbon atoms, at a temperature between about 530.degree. C. (1000.degree. F.) to about 980.degree. C. (1800.degree. F.); and whereby the hydrocarbons are cracked to form hydrogen, carbon monoxide and/or carbon dioxide and the hydrogen content of the mixture increases with a corresponding decrease in carbon monoxide, and carbon formation is substantially eliminated.

  12. Gaseous detonation synthesis and characterization of nano-oxide

    NASA Astrophysics Data System (ADS)

    Yan, Honghao; Wu, Linsong; Li, Xiaojie; Wang, Xiaohong

    2015-07-01

    Gaseous detonation is a new method of heating the precursor of nanomaterials into gas, and integrating it with combustible gas as mixture to be detonated for the synthesis of nanomaterials. In this paper, the mixed gas of oxygen and hydrogen is used as the source for detonation, to synthesize nano TiO2, nano SiO2 and nano SnO2 through gaseous detonation method, characterization and analysis of the products, it was found that the products from gaseous detonation method were of high purity, good dispersion, smaller particle size and even distribution. It also shows that for the synthesis of nano-oxides, gaseous detonation is universal.

  13. THE ECONOMICAL PRODUCTION OF ALCOHOL FUELS FROM COAL-DERIVED SYNTHESIS GAS. Includes quarterly technical progress report No.25 from 10/01/1997-12/31/1997, and quarterly technical progress report No.26 from 01/01/1998-03/31/1998

    SciTech Connect

    1999-03-01

    This project was divided into two parts. One part evaluated possible catalysts for producing higher-alcohols (C{sub 2} to C{sub 5+}) as fuel additives. The other part provided guidance by looking both at the economics of mixed-alcohol production from coal-derived syngas and the effect of higher alcohol addition on gasoline octane and engine performance. The catalysts studied for higher-alcohol synthesis were molybdenum sulfides promoted with potassium. The best catalysts produced alcohols at a rate of 200 g/kg of catalyst/h. Higher-alcohol selectivity was over 40%. The hydrocarbon by-product was less than 20%. These catalysts met established success criteria. The economics for mixed alcohols produced from coal were poor compared to mixed alcohols produced from natural gas. Syngas from natural gas was always less expensive than syngas from coal. Engine tests showed that mixed alcohols added to gasoline significantly improved fuel quality. Mixed-alcohols as produced by our catalysts enhanced gasoline octane and decreased engine emissions. Mixed-alcohol addition gave better results than adding individual alcohols as had been done in the 1980's when some refiners added methanol or ethanol to gasoline.

  14. Gas separations using inorganic membranes

    SciTech Connect

    Egan, B.Z.; Singh, S.P.N.; Fain, D.E.; Roettger, G.E.; White, D.E.

    1992-04-01

    This report summarizes the results from a research and development program to develop, fabricate, and evaluate inorganic membranes for separating gases at high temperatures and pressures in hostile process environments encountered in fossil energy conversion processes such as coal gasification. The primary emphasis of the research was on the separation and recovery of hydrogen from synthesis gas. Major aspects of the program included assessment of the worldwide research and development activity related to gas separations using inorganic membranes, identification and selection of candidate membrane materials, fabrication and characterization of membranes using porous membrane technology developed at the Oak Ridge K-25 Site, and evaluation of the separations capability of the fabricated membranes in terms of permeabilities and fluxes of gases.

  15. Microporous metal organic framework [M{sub 2}(hfipbb){sub 2}(ted)] (M=Zn, Co; H{sub 2}hfipbb=4,4-(hexafluoroisopropylidene)-bis(benzoic acid); ted=triethylenediamine): Synthesis, structure analysis, pore characterization, small gas adsorption and CO{sub 2}/N{sub 2} separation properties

    SciTech Connect

    Xu, William W.; Pramanik, Sanhita; Zhang, Zhijuan; Emge, Thomas J.; Li, Jing

    2013-04-15

    Carbon dioxide is a greenhouse gas that is a major contributor to global warming. Developing methods that can effectively capture CO{sub 2} is the key to reduce its emission to the atmosphere. Recent research shows that microporous metal organic frameworks (MOFs) are emerging as a promising family of adsorbents that may be promising for use in adsorption based capture and separation of CO{sub 2} from power plant waste gases. In this work we report the synthesis, crystal structure analysis and pore characterization of two microporous MOF structures, [M{sub 2}(hfipbb){sub 2}(ted)] (M=Zn (1), Co (2); H{sub 2}hfipbb=4,4-(hexafluoroisopropylidene)-bis(benzoic acid); ted=triethylenediamine). The CO{sub 2} and N{sub 2} adsorption experiments and IAST calculations are carried out on [Zn{sub 2}(hfipbb){sub 2}(ted)] under conditions that mimic post-combustion flue gas mixtures emitted from power plants. The results show that the framework interacts with CO{sub 2} strongly, giving rise to relatively high isosteric heats of adsorption (up to 28 kJ/mol), and high adsorption selectivity for CO{sub 2} over N{sub 2}, making it promising for capturing and separating CO{sub 2} from CO{sub 2}/N{sub 2} mixtures. - Graphical abstract: Microporous [Zn{sub 2}(hfipbb){sub 2}(ted)] demonstrates high adsorption selectivity for CO{sub 2} over N{sub 2} under conditions that mimic flue gas mixtures. Highlights: ► Two new porous MOFs were synthesized and characterized by rational design. ► The small pore size leads to greatly enhanced CO{sub 2}–MOF interaction. ► High adsorption selectivity of the Zn–MOF for CO{sub 2} over N{sub 2} is achieved.

  16. Sweet gas

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    When poisonous hydrogen sulfide contaminates a natural gas deposit, the drilling company usually caps the well and moves on to other areas that may contain larger reserves and offer stronger economic incentives. Chemical and biological methods exist to purify these wells, but most are complex and costly. However, a group of scientists now is developing what could be a cheaper, easier method to clean up and utilize this polluted natural gas.The technique—which involves growing “enrichment” cultures of bacteria that metabolize the hydrogen sulfide into harmless compounds—could be particularly useful to poor and energy-starved developing nations, says Norman Wainwright, a senior scientist at the Woods Hole Marine Biological Laboratory. “We're hoping the technique can be robust enough and inexpensive enough to be used in a developing country,” Wainwright says. Other scientists involved with the project are Porter Anderson, a University of Rochester professor emeritus associated with the lab and Ben Ebenhack, also of Rochester.

  17. LOW NOx EMISSIONS IN A FUEL FLEXIBLE GAS TURBINE

    SciTech Connect

    Raymond Drnevich; James Meagher; Vasilis Papavassiliou; Troy Raybold; Peter Stuttaford; Leonard Switzer; Lee Rosen

    2004-08-01

    In alignment with Vision 21 goals, a study is presented here on the technical and economic potential for developing a gas turbine combustor that is capable of generating less that 2 ppm NOx emissions, firing on either coal synthesis gas or natural gas, and being implemented on new and existing systems. The proposed solution involves controlling the quantity of H2 contained in the fuel. The presence of H2 leads to increased flame stability such that the combustor can be operated at lower temperatures and produce less thermal NOx. Coal gas composition would be modified using a water gas shift converter, and natural gas units would implement a catalytic partial oxidation (CPOX) reactor to convert part of the natural gas feed to a syngas before fed back into the combustor. While both systems demonstrated technical merit, the economics involved in implementing such a system are marginal at best. Therefore, Praxair has decided not to pursue the technology any further at this time.

  18. Novel synthesis of substituted benzylidenecyclohexanone by microwave assisted organic synthesis

    NASA Astrophysics Data System (ADS)

    Handayani, Sri; Budimarwanti, Cornelia; Haryadi, Winarto

    2017-03-01

    Benzylidenecyclohexanone derivatives are compounds with wide bioactivity. Usually, it was synthesized from cyclohexanones and benzaldehyde derivatives under base condition. This research presents a rapid and simple method to synthesis substituted benzylidenecyclohexanone. Cyclohexanone was mixed with 4-hydroxybenzaldehyde in acid condition under MAOS for 2 minutes, then it was left to cooled. Brownish purple powder in 81.47% yield was obtained. The product was identified by gas chromatography, then followed by structure elucidation by using NMR spectrophotometer. The novel compound is confirmed as 4-((E)-((1E,3'E)-3'-(4-hydroxybenzylidene)-2'-oxo-[1,1'-bi(cyclohexylidene)]-2,5-dienylidene-4-ylidene) me-thoxy)benzaldehyde.

  19. Fuel gas conditioning process

    DOEpatents

    Lokhandwala, Kaaeid A.

    2000-01-01

    A process for conditioning natural gas containing C.sub.3+ hydrocarbons and/or acid gas, so that it can be used as combustion fuel to run gas-powered equipment, including compressors, in the gas field or the gas processing plant. Compared with prior art processes, the invention creates lesser quantities of low-pressure gas per unit volume of fuel gas produced. Optionally, the process can also produce an NGL product.

  20. Economic and Technical Assessment of Wood Biomass Fuel Gasification for Industrial Gas Production

    SciTech Connect

    Anastasia M. Gribik; Ronald E. Mizia; Harry Gatley; Benjamin Phillips

    2007-09-01

    This project addresses both the technical and economic feasibility of replacing industrial gas in lime kilns with synthesis gas from the gasification of hog fuel. The technical assessment includes a materials evaluation, processing equipment needs, and suitability of the heat content of the synthesis gas as a replacement for industrial gas. The economic assessment includes estimations for capital, construction, operating, maintenance, and management costs for the reference plant. To perform these assessments, detailed models of the gasification and lime kiln processes were developed using Aspen Plus. The material and energy balance outputs from the Aspen Plus model were used as inputs to both the material and economic evaluations.

  1. Tunable composite membranes for gas separations. Quarterly technical progress report, May--July 1996

    SciTech Connect

    Ferraris, J.P.; Balkus, K.J. Jr.; Musselman, I.H.

    1996-08-05

    Significant progress has been made in the synthesis and characterization of conducting polymer composite membranes for gas separations. Zeolite/polyalkylthiophene composite membranes have been prepared and characterized for zeolite NaY.

  2. Microporous organic polymers for gas storage and separation applications.

    PubMed

    Chang, Ze; Zhang, Da-Shuai; Chen, Qiang; Bu, Xian-He

    2013-04-21

    Microporous organic polymers (MOPs), an emerging class of functional porous materials featured with the pure organic component have been widely studied in recent years. These materials have potential uses in areas such as storage, separation, and catalysis. In this Perspective, we focused on the gas storage and separation of MOPs. The targeted design and synthesis of MOPs toward the enhancement of gas capacity and selectivity are discussed. Furthermore, special emphasis is given to the post-synthesis modification of MOPs which have been proved to be effective methods to accurately tune the desired properties.

  3. Method of Generating Hydrocarbon Reagents from Diesel, Natural Gas and Other Logistical Fuels

    DOEpatents

    Herling, Darrell R [Richland, WA; Aardahl, Chris L [Richland, WA; Rozmiarek, Robert T [Middleton, WI; Rappe, Kenneth G [Richland, WA; Wang, Yong [Richland, WA; Holladay, Jamelyn D [Kennewick, WA

    2008-10-14

    The present invention provides a process for producing reagents for a chemical reaction by introducing a fuel containing hydrocarbons into a flash distillation process wherein the fuel is separated into a first component having a lower average molecular weight and a second component having a higher average molecular weight. The first component is then reformed to produce synthesis gas wherein the synthesis gas is reacted catalytically to produce the desire reagent.

  4. Method of generating hydrocarbon reagents from diesel, natural gas and other logistical fuels

    DOEpatents

    Herling, Darrell R.; Aardahl, Chris L.; Rozmiarek, Robert T.; Rappe, Kenneth G.; Wang, Yong; Holladay, Jamelyn D.

    2010-06-29

    The present invention provides a process for producing reagents for a chemical reaction by introducing a fuel containing hydrocarbons into a flash distillation process wherein the fuel is separated into a first component having a lower average molecular weight and a second component having a higher average molecular weight. The first component is then reformed to produce synthesis gas wherein the synthesis gas is reacted catalytically to produce the desire reagent.

  5. Gas Chromatography

    NASA Astrophysics Data System (ADS)

    Qian, Michael C.

    Gas chromatography (GC) has many applications in the analysis of food products. GC has been used for the determination of fatty acids, triglycerides, cholesterol, gases, water, alcohols, pesticides, flavor compounds, and many more. While GC has been used for other food components such as sugars, oligosaccharides, amino acids, peptides, and vitamins, these substances are more suited to analysis by high performance liquid chromatography. GC is ideally suited to the analysis of volatile substances that are thermally stable. Substances such as pesticides and flavor compounds that meet these criteria can be isolated from a food and directly injected into the GC. For compounds that are thermally unstable, too low in volatility, or yield poor chromatographic separation due to polarity, a derivatization step must be done before GC analysis. The two parts of the experiment described here include the analysis of alcohols that requires no derivatization step, and the analysis of fatty acids which requires derivatization. The experiments specify the use of capillary columns, but the first experiment includes conditions for a packed column.

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

    PubMed

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

    2015-07-07

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

  7. Noble gas fractionation during subsurface gas migration

    NASA Astrophysics Data System (ADS)

    Sathaye, Kiran J.; Larson, Toti E.; Hesse, Marc A.

    2016-09-01

    Environmental monitoring of shale gas production and geological carbon dioxide (CO2) storage requires identification of subsurface gas sources. Noble gases provide a powerful tool to distinguish different sources if the modifications of the gas composition during transport can be accounted for. Despite the recognition of compositional changes due to gas migration in the subsurface, the interpretation of geochemical data relies largely on zero-dimensional mixing and fractionation models. Here we present two-phase flow column experiments that demonstrate these changes. Water containing a dissolved noble gas is displaced by gas comprised of CO2 and argon. We observe a characteristic pattern of initial co-enrichment of noble gases from both phases in banks at the gas front, followed by a depletion of the dissolved noble gas. The enrichment of the co-injected noble gas is due to the dissolution of the more soluble major gas component, while the enrichment of the dissolved noble gas is due to stripping from the groundwater. These processes amount to chromatographic separations that occur during two-phase flow and can be predicted by the theory of gas injection. This theory provides a mechanistic basis for noble gas fractionation during gas migration and improves our ability to identify subsurface gas sources after post-genetic modification. Finally, we show that compositional changes due to two-phase flow can qualitatively explain the spatial compositional trends observed within the Bravo Dome natural CO2 reservoir and some regional compositional trends observed in drinking water wells overlying the Marcellus and Barnett shale regions. In both cases, only the migration of a gas with constant source composition is required, rather than multi-stage mixing and fractionation models previously proposed.

  8. Gas amplified ionization detector for gas chromatography

    DOEpatents

    Huston, Gregg C.

    1992-01-01

    A gas-amplified ionization detector for gas chromatrography which possesses increased sensitivity and a very fast response time. Solutes eluding from a gas chromatographic column are ionized by UV photoionization of matter eluting therefrom. The detector is capable of generating easily measured voltage signals by gas amplification/multiplication of electron products resulting from the UV photoionization of at least a portion of each solute passing through the detector.

  9. Synthesis and development of processes for the recovery of sulfur from acid gases. Part 1, Development of a high-temperature process for removal of H{sub 2}S from coal gas using limestone -- thermodynamic and kinetic considerations; Part 2, Development of a zero-emissions process for recovery of sulfur from acid gas streams

    SciTech Connect

    Towler, G.P.; Lynn, S.

    1993-05-01

    Limestone can be used more effectively as a sorbent for H{sub 2}S in high-temperature gas-cleaning applications if it is prevented from undergoing calcination. Sorption of H{sub 2}S by limestone is impeded by sintering of the product CaS layer. Sintering of CaS is catalyzed by CO{sub 2}, but is not affected by N{sub 2} or H{sub 2}. The kinetics of CaS sintering was determined for the temperature range 750--900{degrees}C. When hydrogen sulfide is heated above 600{degrees}C in the presence of carbon dioxide elemental sulfur is formed. The rate-limiting step of elemental sulfur formation is thermal decomposition of H{sub 2}S. Part of the hydrogen thereby produced reacts with CO{sub 2}, forming CO via the water-gas-shift reaction. The equilibrium of H{sub 2}S decomposition is therefore shifted to favor the formation of elemental sulfur. The main byproduct is COS, formed by a reaction between CO{sub 2} and H{sub 2}S that is analogous to the water-gas-shift reaction. Smaller amounts of SO{sub 2} and CS{sub 2} also form. Molybdenum disulfide is a strong catalyst for H{sub 2}S decomposition in the presence of CO{sub 2}. A process for recovery of sulfur from H{sub 2}S using this chemistry is as follows: Hydrogen sulfide is heated in a high-temperature reactor in the presence of CO{sub 2} and a suitable catalyst. The primary products of the overall reaction are S{sub 2}, CO, H{sub 2} and H{sub 2}O. Rapid quenching of the reaction mixture to roughly 600{degrees}C prevents loss Of S{sub 2} during cooling. Carbonyl sulfide is removed from the product gas by hydrolysis back to CO{sub 2} and H{sub 2}S. Unreacted CO{sub 2} and H{sub 2}S are removed from the product gas and recycled to the reactor, leaving a gas consisting chiefly of H{sub 2} and CO, which recovers the hydrogen value from the H{sub 2}S. This process is economically favorable compared to the existing sulfur-recovery technology and allows emissions of sulfur-containing gases to be controlled to very low levels.

  10. Pollution Control Technical Manual for Lurgi-based indirect coal liquefaction and SNG (substitute natural gas). Final report Jun 82-Feb 83

    SciTech Connect

    Not Available

    1983-04-01

    The Environmental Protection Agency (EPA), Office of Research and Development has undertaken an extensive study to determine synthetic fuel plant waste stream characteristics and to evaluate potentially applicable pollution control systems. The purpose of this and all other PCTMs is to convey this information in a manner that is readily useful to designers, permit writers, and the public. This specific PCTM addresses coal-based synthetic fuels facilities using dry ash Lurgi gasifiers to generate a synthesis process feed gas. Product synthesis technologies examined in this PCTM include: methanation to produce substitute natural gas (SNG), methanol synthesis, Mobil M-gasoline synthesis from methanol, and Fischer-Tropsch synthesis.

  11. Coalbed gas development

    SciTech Connect

    Not Available

    1992-01-01

    This book includes: Overview of coalbed gas development; Coalbed gas development in the West Coalbed gas development on Indian lands; Multi-mineral development conflicts; Statutory solutions to ownership disputes; State and local regulation; Environmental regulations; Status of the section 29 tax credit extension; Using the section 29 credit; Leasing coalbed gas prospects; Coalbed gas joint operating agreements and Purchase and sale agreements for coalbed gas properties.

  12. CONTINUOUS GAS ANALYZER

    DOEpatents

    Katz, S.; Weber, C.W.

    1960-02-16

    A reagent gas and a sample gas are chemically combined on a continuous basis in a reaction zone maintained at a selected temperature. The reagent gas and the sample gas are introduced to the reaction zone at preselected. constant molar rates of flow. The reagent gas and the selected gas in the sample mixture combine in the reaction zone to form a product gas having a different number of moles from the sum of the moles of the reactants. The difference in the total molar rates of flow into and out of the reaction zone is measured and indicated to determine the concentration of the selected gas.

  13. Selective n-butanol production by Clostridium sp. MTButOH1365 during continuous synthesis gas fermentation due to expression of synthetic thiolase, 3-hydroxy butyryl-CoA dehydrogenase, crotonase, butyryl-CoA dehydrogenase, butyraldehyde dehydrogenase, and NAD-dependent butanol dehydrogenase.

    PubMed

    Berzin, Vel; Tyurin, Michael; Kiriukhin, Michael

    2013-02-01

    Acetogen Clostridum sp. MT1962 produced 287 mM acetate (p < 0.005) and 293 mM ethanol (p < 0.005) fermenting synthesis gas blend 60% CO and 40% H₂ in single-stage continuous fermentation. This strain was metabolically engineered to the biocatalyst Clostridium sp. MTButOH1365. The engineered biocatalyst lost production of ethanol and acetate while initiated the production of 297 mM of n-butanol (p < 0.005). The metabolic engineering comprised Cre-lox66/lox71-based elimination of phosphotransacetylase and acetaldehyde dehydrogenase along with integration to chromosome synthetic thiolase, 3-hydroxy butyryl-CoA dehydrogenase, crotonase, butyryl-CoA dehydrogenase, butyraldehyde dehydrogenase, and NAD-dependent butanol dehydrogenase. This is the first report on elimination of acetate and ethanol production genes and expression of synthetic gene cluster encoding n-butanol biosynthesis pathway in acetogen biocatalyst for selective fuel n-butanol production with no antibiotic support for the introduced genes.

  14. Analysis of operation of the gas turbine in a poligeneration combined cycle

    NASA Astrophysics Data System (ADS)

    Bartela, Łukasz; Kotowicz, Janusz

    2013-12-01

    In the paper the results of analysis of an integrated gasification combined cycle IGCC polygeneration system, of which the task is to produce both electricity and synthesis gas, are shown. Assuming the structure of the system and the power rating of a combined cycle, the consumption of the synthesis gas for chemical production makes it necessary to supplement the lack of synthesis gas used for electricity production with the natural gas. As a result a change of the composition of the fuel gas supplied to the gas turbine occurs. In the paper the influence of the change of gas composition on the gas turbine characteristics is shown. In the calculations of the gas turbine the own computational algorithm was used. During the study the influence of the change of composition of gaseous fuel on the characteristic quantities was examined. The calculations were realized for different cases of cooling of the gas turbine expander's blades (constant cooling air mass flow, constant cooling air index, constant temperature of blade material). Subsequently, the influence of the degree of integration of the gas turbine with the air separation unit on the main characteristics was analyzed.

  15. The hydrothermal synthesis of tetragonal tungsten bronze-based catalysts for the selective oxidation of hydrocarbons.

    PubMed

    Botella, Pablo; Solsona, Benjamín; García-González, Ester; González-Calbet, José M; López Nieto, José M

    2007-12-21

    Mixed metal oxides with tetragonal tungsten bronze (TTB) structure, showing high activity and selectivity for the gas phase partial oxidation of olefins, have been prepared by hydrothermal synthesis from Keggin-type heteropolyacids.

  16. Modified Synthesis of Erlotinib Hydrochloride

    PubMed Central

    Barghi, Leila; Aghanejad, Ayuob; Valizadeh, Hadi; Barar, Jaleh; Asgari, Davoud

    2012-01-01

    Purpose: An improved and economical method has been described for the synthesis of erlotinib hydrochloride, as a useful drug in treatment of non-small-cell lung cancer. Method: Erlotinib hydrochloride was synthesized in seven steps starting from 3, 4-dihydroxy benzoic acid. In this study, we were able to modify one of the key steps which involved the reduction of the 6-nitrobenzoic acid derivative to 6-aminobenzoic acid derivative. An inexpensive reagent such as ammonium formate was used as an in situ hydrogen donor in the presence of palladium/charcoal (Pd/C) instead of hydrogen gas at high pressure. Result: This proposed method proceeded with 92% yield at room temperature. Synthesis of erlotinib was completed in 7 steps with overall yield of 44%. Conclusion: From the results obtained it can be concluded that the modified method eliminated the potential danger associated with the use of hydrogen gas in the presence of flammable catalysts. It should be mentioned that the catalyst was recovered after the reaction and could be used again. PMID:24312780

  17. Ethylene synthesis and sensitivity in crop plants

    NASA Technical Reports Server (NTRS)

    Klassen, Stephen P.; Bugbee, Bruce

    2004-01-01

    Closed and semi-closed plant growth chambers have long been used in studies of plant and crop physiology. These studies include the measurement of photosynthesis and transpiration via photosynthetic gas exchange. Unfortunately, other gaseous products of plant metabolism can accumulate in these chambers and cause artifacts in the measurements. The most important of these gaseous byproducts is the plant hormone ethylene (C2H4). In spite of hundreds of manuscripts on ethylene, we still have a limited understanding of the synthesis rates throughout the plant life cycle. We also have a poor understanding of the sensitivity of intact, rapidly growing plants to ethylene. We know ethylene synthesis and sensitivity are influenced by both biotic and abiotic stresses, but such whole plant responses have not been accurately quantified. Here we present an overview of basic studies on ethylene synthesis and sensitivity.

  18. Synthesis, structure and gas-phase reactivity of the mixed silver hydride borohydride nanocluster [Ag3(μ3-H)(μ3-BH4)LPh3]BF4 (LPh = bis(diphenylphosphino)methane)

    NASA Astrophysics Data System (ADS)

    Zavras, Athanasios; Ariafard, Alireza; Khairallah, George N.; White, Jonathan M.; Mulder, Roger J.; Canty, Allan J.; O'Hair, Richard A. J.

    2015-10-01

    Borohydrides react with silver salts to give products that span multiple scales ranging from discrete mononuclear compounds through to silver nanoparticles and colloids. The cluster cations [Ag3(H)(BH4)L3]+ are observed upon electrospray ionization mass spectrometry of solutions containing sodium borohydride, silver(i) tetrafluoroborate and bis(dimethylphosphino)methane (LMe) or bis(diphenylphosphino)methane (LPh). By adding NaBH4 to an acetonitrile solution of AgBF4 and LPh, cooled to ca. -10 °C, we have been able to isolate the first mixed silver hydride borohydride nanocluster, [Ag3(μ3-H)(μ3-BH4)LPh3]BF4, and structurally characterise it via X-ray crystallography. Combined gas-phase experiments (LMe and LPh) and DFT calculations (LMe) reveal how loss of a ligand from the cationic complexes [Ag3(H)(BH4)L3]+ provides a change in geometry that facilitates subsequent loss of BH3 to produce the dihydride clusters, [Ag3(H)2Ln]+ (n = 1 and 2). Together with the results of previous studies (Girod et al., Chem. - Eur. J., 2014, 20, 16626), this provides a direct link between mixed silver hydride/borohydride nanoclusters, silver hydride nanoclusters, and silver nanoclusters.Borohydrides react with silver salts to give products that span multiple scales ranging from discrete mononuclear compounds through to silver nanoparticles and colloids. The cluster cations [Ag3(H)(BH4)L3]+ are observed upon electrospray ionization mass spectrometry of solutions containing sodium borohydride, silver(i) tetrafluoroborate and bis(dimethylphosphino)methane (LMe) or bis(diphenylphosphino)methane (LPh). By adding NaBH4 to an acetonitrile solution of AgBF4 and LPh, cooled to ca. -10 °C, we have been able to isolate the first mixed silver hydride borohydride nanocluster, [Ag3(μ3-H)(μ3-BH4)LPh3]BF4, and structurally characterise it via X-ray crystallography. Combined gas-phase experiments (LMe and LPh) and DFT calculations (LMe) reveal how loss of a ligand from the cationic complexes [Ag

  19. Study the gas sensing properties of boron nitride nanosheets

    SciTech Connect

    Sajjad, Muhammad; Feng, Peter

    2014-01-01

    Graphical abstract: - Highlights: • We synthesized boron nitride nanosheets (BNNSs) on silicon substrate. • We analyzed gas sensing properties of BNNSs-based gas-sensor device. • CH{sub 4} gas is used to measure gas-sensing properties of the device. • Quick response and recovery time of the device is recorded. • BNNSs showed excellent sensitivity to the working gas. - Abstract: In the present communication, we report on the synthesis of boron nitride nanosheets (BNNSs) and study of their gas sensing properties. BNNSs are synthesized by irradiating pyrolytic hexagonal boron nitride (h-BN) target using CO{sub 2} laser pulses. High resolution transmission electron microscopic measurements (HRTEM) revealed 2-dientional honeycomb crystal lattice structure of BNNSs. HRTEM, electron diffraction, XRD and Raman scattering measurements clearly identified h-BN. Gas sensing properties of synthesized BNNSs were analyzed with prototype gas sensor using methane as working gas. A systematic response curve of the sensor is recorded in each cycle of gas “in” and “out”; suggesting excellent sensitivity and high performance of BNNSs-based gas-sensor.

  20. Noble gas magnetic resonator

    DOEpatents

    Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert

    2014-04-15

    Precise measurements of a precessional rate of noble gas in a magnetic field is obtained by constraining the time averaged direction of the spins of a stimulating alkali gas to lie in a plane transverse to the magnetic field. In this way, the magnetic field of the alkali gas does not provide a net contribution to the precessional rate of the noble gas.