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Sample records for hydrogen gas getters

  1. Improved Hydrogen Gas Getters for TRU Waste -- Final Report

    SciTech Connect

    Mark Stone; Michael Benson; Christopher Orme; Thomas Luther; Eric Peterson

    2005-09-01

    Alpha radiolysis of hydrogenous waste and packaging materials generates hydrogen gas in radioactive storage containers. For that reason, the Nuclear Regulatory Commission limits the flammable gas (hydrogen) concentration in the Transuranic Package Transporter-II (TRUPACT-II) containers to 5 vol% of hydrogen in air, which is the lower explosion limit. Consequently, a method is needed to prevent the build up of hydrogen to 5 vol% during the storage and transport of the TRUPACT-II containers (up to 60 days). One promising option is the use of hydrogen getters. These materials scavenge hydrogen from the gas phase and irreversibly bind it in the solid phase. One proven getter is a material called 1,4-bis (phenylethynyl) benzene, or DEB, characterized by the presence of carbon-carbon triple bonds. Carbon may, in the presence of suitable precious metal catalysts such as palladium, irreversibly react with and bind hydrogen. In the presence of oxygen, the precious metal may also eliminate hydrogen by catalyzing the formation of water. This reaction is called catalytic recombination. DEB has the needed binding rate and capacity for hydrogen that potentially could be generated in the TRUPACT II. Phases 1 and 2 of this project showed that uncoated DEB performed satisfactorily in lab scale tests. Based upon these results, Phase 3, the final project phase, included larger scale testing. Test vessels were scaled to replicate the ratio between void space in the inner containment vessel of a TRUPACT-II container and a payload of seven 55-gallon drums. The tests were run with an atmosphere of air for 63.9 days at ambient temperature (15-27°C) and a scaled hydrogen generation rate of 2.60E-07 moles per second (0.35 cc/min). A second type of getter known as VEI, a proprietary polymer hydrogen getter characterized by carbon-carbon double bonds, was also tested in Phase 3. Hydrogen was successfully “gettered” by both getter systems. Hydrogen concentrations remained below 5 vol% (in

  2. Hydrogen gettering the overpressure gas from highly radioactive liquids

    SciTech Connect

    Riley, D.L.; McCoy, J.C.; Schicker, J.R.

    1996-04-01

    Remediation of current inventories of high-activity radioactive liquid waste (HALW) requires transportation of Type-B quantities of radioactive material, possibly up to several hundred liters. However, the only currently certified packaging is limited to quantities of 50 ml (0.01 gal) quantities of Type-B radioactive liquid. Efforts are under way to recertify the existing packaging to allow the shipment of up to 4 L (1.1 gal) of Type-B quantities of HALW, but significantly larger packaging could be needed in the future. Scoping studies and preliminary designs have identified the feasibility of retrofitting an insert into existing casks, allowing the transport of up to 380 L (100 gal) of HALW. However, the insert design and ultimate certification strategy depend heavily on the gas-generating attributes of the HALW. A non-vented containment vessel filled with HALW, in the absence of any gas-mitigation technologies, poses a deflagration threat and, therefore, gas generation, specifically hydrogen generation, must be reliably controlled during all phases of transportation. Two techniques are available to mitigate hydrogen accumulation: recombiners and getters. Getters have an advantage over recombiners in that oxides are not required to react with the hydrogen. A test plan was developed to evaluate three forms of getter material in the presence of both simulated HALW and the gases that are produced by the HALW. These tests demonstrated that getters can react with hydrogen in the presence of simulated waste and in the presence of several other gases generated by the HALW, such as nitrogen, ammonia, nitrous oxide, and carbon monoxide. Although the use of such a gettering system has been shown to be technically feasible, only a preliminary design for its use has been completed. No further development is planned until the requirement for bulk transport of Type-B quantities of HALW is more thoroughly defined.

  3. Gettering of hydrogen and methane from a helium gas mixture

    SciTech Connect

    Cárdenas, Rosa Elia; Stewart, Kenneth D.; Cowgill, Donald F.

    2014-11-01

    In this study, the authors developed an approach for accurately quantifying the helium content in a gas mixture also containing hydrogen and methane using commercially available getters. The authors performed a systematic study to examine how both H{sub 2} and CH{sub 4} can be removed simultaneously from the mixture using two SAES St 172{sup ®} getters operating at different temperatures. The remaining He within the gas mixture can then be measured directly using a capacitance manometer. The optimum combination involved operating one getter at 650 °C to decompose the methane, and the second at 110 °C to remove the hydrogen. This approach eliminated the need to reactivate the getters between measurements, thereby enabling multiple measurements to be made within a short time interval, with accuracy better than 1%. The authors anticipate that such an approach will be particularly useful for quantifying the He-3 in mixtures that include tritium, tritiated methane, and helium-3. The presence of tritiated methane, generated by tritium activity, often complicates such measurements.

  4. Gettering of Hydrogen and Methane from a Helium Gas Mixture

    SciTech Connect

    Cardenas, Rosa E.; Stewart, Kenneth D.; Cowgill, Donald F.

    2014-10-21

    In our study, the authors developed an approach for accurately quantifying the helium content in a gas mixture also containing hydrogen and methane using commercially available getters. The authors performed a systematic study to examine how both H2 and CH4 can be removed simultaneously from the mixture using two SAES St 172® getters operating at different temperatures. The remaining He within the gas mixture can then be measured directly using a capacitance manometer. Moreover, the optimum combination involved operating one getter at 650°C to decompose the methane, and the second at 110°C to remove the hydrogen. Finally, this approach eliminated the need to reactivate the getters between measurements, thereby enabling multiple measurements to be made within a short time interval, with accuracy better than 1%. The authors anticipate that such an approach will be particularly useful for quantifying the He-3 in mixtures that include tritium, tritiated methane, and helium-3. The presence of tritiated methane, generated by tritium activity, often complicates such measurements.

  5. Gettering of Hydrogen and Methane from a Helium Gas Mixture

    DOE PAGES

    Cardenas, Rosa E.; Stewart, Kenneth D.; Cowgill, Donald F.

    2014-10-21

    In our study, the authors developed an approach for accurately quantifying the helium content in a gas mixture also containing hydrogen and methane using commercially available getters. The authors performed a systematic study to examine how both H2 and CH4 can be removed simultaneously from the mixture using two SAES St 172® getters operating at different temperatures. The remaining He within the gas mixture can then be measured directly using a capacitance manometer. Moreover, the optimum combination involved operating one getter at 650°C to decompose the methane, and the second at 110°C to remove the hydrogen. Finally, this approach eliminatedmore » the need to reactivate the getters between measurements, thereby enabling multiple measurements to be made within a short time interval, with accuracy better than 1%. The authors anticipate that such an approach will be particularly useful for quantifying the He-3 in mixtures that include tritium, tritiated methane, and helium-3. The presence of tritiated methane, generated by tritium activity, often complicates such measurements.« less

  6. Combination moisture and hydrogen getter

    DOEpatents

    Not Available

    1982-04-29

    A combination moisture and hydrogen getter comprises (a) a moisture getter comprising a readily oxidizable metal; and (b) a hydrogen getter comprising (i) a solid acetylenic compound and (ii) a hydrogenation catalyst. A method of scavenging moisture from a closed container uses the combination moisture and hydrogen getter to irreversibly chemically reduce the moisture and chemically bind the reusltant hydrogen.

  7. Combination moisture and hydrogen getter

    DOEpatents

    Harrah, Larry A.; Mead, Keith E.; Smith, Henry M.

    1983-01-01

    A combination moisture and hydrogen getter comprises (a) a moisture getter comprising a readily oxidizable metal; and (b) a hydrogen getter comprising (i) a solid acetylenic compound and (ii) a hydrogenation catalyst. A method of scavenging moisture from a closed container uses the combination moisture and hydrogen getter to irreversibly chemically reduce the moisture and chemically bind the resultant hydrogen.

  8. Combination moisture and hydrogen getter

    DOEpatents

    Harrah, L.A.; Mead, K.E.; Smith, H.M.

    1983-09-20

    A combination moisture and hydrogen getter comprises (a) a moisture getter comprising a readily oxidizable metal; and (b) a hydrogen getter comprising (1) a solid acetylenic compound and (2) a hydrogenation catalyst. A method of scavenging moisture from a closed container uses the combination moisture and hydrogen getter to irreversibly chemically reduce the moisture and chemically bind the resultant hydrogen.

  9. Oxidation resistant organic hydrogen getters

    DOEpatents

    Shepodd, Timothy J.; Buffleben, George M.

    2008-09-09

    A composition for removing hydrogen from an atmosphere, comprising a mixture of a polyphenyl ether and a hydrogenation catalyst, preferably a precious metal catalyst, and most preferably Pt. This composition is stable in the presence of oxygen, will not polymerize or degrade upon exposure to temperatures in excess of 200.degree. C., or prolonged exposure to temperatures in the range of 100-300.degree. C. Moreover, these novel hydrogen getter materials can be used to efficiently removing hydrogen from mixtures of hydrogen/inert gas (e.g., He, Ar, N.sub.2), hydrogen/ammonia atmospheres, such as may be encountered in heat exchangers, and hydrogen/carbon dioxide atmospheres. Water vapor and common atmospheric gases have no adverse effect on the ability of these getter materials to absorb hydrogen.

  10. Improved Hydrogen Gas Getters for TRU Waste Transuranic and Mixed Waste Focus Area - Phase 2 Final Report

    SciTech Connect

    Stone, Mark Lee

    2002-04-01

    Alpha radiolysis of hydrogenous waste and packaging materials generates hydrogen gas in radioactive storage containers. For that reason, the Nuclear Regulatory Commission (NRC) limits the flammable gas (hydrogen) concentration in the Transuranic Package Transporter-II (TRUPACT-II) containers to 5 vol% of hydrogen in air, which is the lower explosion limit. Consequently, a method is needed to prevent the build up of hydrogen to 5 vol% during the storage and transport of the TRUPACT-II containers (up to 60 days). One promising option is the use of hydrogen getters. These materials scavenge hydrogen from the gas phase and irreversibly bind it in the solid phase. One proven getter is a material called 1,4-bis (phenylethynyl) benzene, or DEB. It has the needed binding rate and capacity, but some of the chemical species that might be present in the containers could interfere with its ability to remove hydrogen. This project is focused upon developing a protective polymeric membrane coating for the DEB getter material, which comes in the form of small, irregularly shaped particles. This report summarizes the experimental results of the second phase of the development of the materials.

  11. Hydrogen and moisture getter and absorber for sealed devices

    DOEpatents

    Smith, H.M.; Schicker, J.R.

    1999-03-30

    The present invention is a hydrogen getter and method for formulating and using the getter. This getter effectively removes hydrogen gas typically present in many hermetically-sealed electronic applications where the presence of such gas would otherwise be harmful to the electronics. The getter is a non-organic composition, usable in a wide range of temperatures as compared to organic getters. Moreover, the getter is formulated to be used without the need for the presence of oxygen. The getter is comprised of effective amounts of an oxide of a platinum group metal, a desiccant, and a gas permeable binder which preferably is cured after composition in an oxygen-bearing environment at about 150 to about 205 degrees centigrade.

  12. Low temperature, low pressure hydrogen gettering

    DOEpatents

    Anderson, D.R.; Courtney, R.L.; Harrah, L.A.

    1975-07-22

    A system is described for the gettering of hydrogen and its isotopes. The gettering materials are painted or coated onto, or otherwise disposed in an area or volume from which hydrogen is to be removed. (auth)

  13. Low temperature, low pressure hydrogen gettering

    DOEpatents

    Anderson, D. Richard; Courtney, Robert L.; Harrah, Larry A.

    1976-06-15

    The invention relates to the gettering of hydrogen and its isotopes, the gettering materials being painted or coated onto, or otherwise disposed in an area or volume from which hydrogen is to be removed.

  14. Development of a Prototype Optical Hydrogen Gas Sensor Using a Getter-Doped Polymer Transducer for Monitoring Cumulative Exposure: Preliminary Results

    SciTech Connect

    Small IV, W; Maitland, D J; Wilson, T S; Bearinger, J P; Letts, S A; Trebes, J E

    2008-06-05

    A novel prototype optical sensor for monitoring cumulative hydrogen gas exposure was fabricated and evaluated. Chemical-to-optical transduction was accomplished by detecting the intensity of 670 nm laser light transmitted through a hydrogen getter-doped polymer film mounted at the end of an optical fiber; the transmittance of the composite film increased with uptake of hydrogen by the embedded getter. The composite film consisted of the hydrogen getter 1,4-bis(phenylethynyl)benzene, also known as DEB, with carbon-supported palladium catalyst embedded in silicone elastomer. Because the change in transmittance was irreversible and occurred continuously as the getter captured hydrogen, the sensor behaved like a dosimeter, providing a unique indication of the cumulative gas exposure.

  15. Polymer system for gettering hydrogen

    DOEpatents

    Shepodd, Timothy Jon; Whinnery, LeRoy L.

    2000-01-01

    A novel composition comprising organic polymer molecules having carbon-carbon double bonds, for removing hydrogen from the atmosphere within enclosed spaces. Organic polymers molecules containing carbon-carbon double bonds throughout their structures, preferably polybutadiene, polyisoprene and derivatives thereof, intimately mixed with an insoluble catalyst composition, comprising a hydrogenation catalyst and a catalyst support, preferably Pd supported on carbon, provide a hydrogen getter composition useful for removing hydrogen from enclosed spaces even in the presence of contaminants such as common atmospheric gases, water vapor, carbon dioxide, ammonia, oil mists, and water. The hydrogen getter composition disclosed herein is particularly useful for removing hydrogen from enclosed spaces containing potentially explosive mixtures of hydrogen and oxygen.

  16. Polymer formulations for gettering hydrogen

    DOEpatents

    Shepodd, Timothy Jon; Whinnery, LeRoy L.

    1998-11-17

    A novel composition comprising organic polymer molecules having carbon-carbon double bonds, for removing hydrogen from the atmosphere within enclosed spaces. Organic polymers molecules containing carbon-carbon double bonds throughout their structures, preferably polybutadiene, polyisoprene and derivatives thereof, intimately mixed with an insoluble catalyst composition, comprising a hydrogenation catalyst and a catalyst support, preferably Pd supported on carbon, provide a hydrogen getter composition useful for removing hydrogen from enclosed spaces even in the presence of contaminants such as common atmospheric gases, water vapor, carbon dioxide, ammonia, oil mists, and water. The hydrogen getter composition disclosed herein is particularly useful for removing hydrogen from enclosed spaces containing potentially explosive mixtures of hydrogen and oxygen.

  17. Polymer formulations for gettering hydrogen

    DOEpatents

    Shepodd, T.J.; Whinnery, L.L.

    1998-11-17

    A novel composition is described comprising organic polymer molecules having carbon-carbon double bonds, for removing hydrogen from the atmosphere within enclosed spaces. Organic polymers molecules containing carbon-carbon double bonds throughout their structures, preferably polybutadiene, polyisoprene and derivatives thereof, intimately mixed with an insoluble catalyst composition, comprising a hydrogenation catalyst and a catalyst support, preferably Pd supported on carbon, provide a hydrogen getter composition useful for removing hydrogen from enclosed spaces even in the presence of contaminants such as common atmospheric gases, water vapor, carbon dioxide, ammonia, oil mists, and water. The hydrogen getter composition disclosed herein is particularly useful for removing hydrogen from enclosed spaces containing potentially explosive mixtures of hydrogen and oxygen. 1 fig.

  18. Polymer system for gettering hydrogen

    SciTech Connect

    2000-05-16

    A novel composition is described comprising organic polymer molecules having carbon-carbon double bonds, for removing hydrogen from the atmosphere within enclosed spaces. Organic polymers molecules containing carbon-carbon double bonds throughout their structures, preferably polybutadiene, polyisoprene and derivatives thereof, intimately mixed with an insoluble catalyst composition, comprising a hydrogenation catalyst and a catalyst support, preferably Pd supported on carbon, provide a hydrogen getter composition useful for removing hydrogen from enclosed spaces even in the presence of contaminants such as common atmospheric gases, water vapor, carbon dioxide, ammonia, oil mists, and water. The hydrogen getter composition disclosed herein is particularly useful for removing hydrogen from enclosed spaces containing potentially explosive mixtures of hydrogen and oxygen.

  19. Method for charging a hydrogen getter

    DOEpatents

    Tracy, C.E.; Keyser, M.A.; Benson, D.K.

    1998-09-15

    A method for charging a sample of either a permanent or reversible getter material with a high concentration of hydrogen while maintaining a base pressure below 10{sup {minus}4} torr at room temperature involves placing the sample of hydrogen getter material in a chamber, activating the sample of hydrogen getter material, overcharging the sample of getter material through conventional charging techniques to a high concentration of hydrogen, and then subjecting the sample of getter material to a low temperature vacuum bake-out process. Application of the method results in a reversible hydrogen getter which is highly charged to maximum capacities of hydrogen and which concurrently exhibits minimum hydrogen vapor pressures at room temperatures. 9 figs.

  20. Method for charging a hydrogen getter

    DOEpatents

    Tracy, C. Edwin; Keyser, Matthew A.; Benson, David K.

    1998-01-01

    A method for charging a sample of either a permanent or reversible getter material with a high concentration of hydrogen while maintaining a base pressure below 10.sup.-4 torr at room temperature involves placing the sample of hydrogen getter material in a chamber, activating the sample of hydrogen getter material, overcharging the sample of getter material through conventional charging techniques to a high concentration of hydrogen, and then subjecting the sample of getter material to a low temperature vacuum bake-out process. Application of the method results in a reversible hydrogen getter which is highly charged to maximum capacities of hydrogen and which concurrently exhibits minimum hydrogen vapor pressures at room temperatures.

  1. Getter pump for hydrogen and hydrocarbon gases

    DOEpatents

    Hsu, Wen Ling

    1987-10-14

    A gettering device for hydrogen isotopes and gaseous hydrocarbons based on the interaction of a plasma and graphite used as cathodic material. The plasma is maintained at a current density within the range of about 1 to about 1000 mA/cm/sup 2/. The graphite may be heated to a temperature greater than 1000/degree/C. The new device offers high capacity, low noise, and gas species selectivity. 2 figs.

  2. Getter pump for hydrogen and hydrocarbon gases

    DOEpatents

    Hsu, Wen L.

    1989-01-01

    A gettering device for hydrogen isotopes and gaseous hydrocarbons based on the interaction of a plasma and graphite used as cathodic material. The plasma is maintained at a current density within the range of about 1 to about 1000 mA/cm.sup.2. The graphite may be heated to a temperature greater than 1000.degree. C. The new device offers high capacity, low noise, and gas species selectivity.

  3. Draft test plan for hydrogen getters project

    SciTech Connect

    Mroz, G.; Weinrach, J.

    1998-04-01

    Hydrogen levels in many transuranic (TRU) waste drums are above the compliance threshold, therefore deeming the drums non-shippable to the Waste Isolation Pilot Plant (WIPP). Hydrogen getters (alkynes and dialkynes) are known to react irreversibly with hydrogen in the presence of certain catalysts. The primary purpose of this investigation is to ascertain the effectiveness of a hydrogen getter in an environment that contains gaseous compounds commonly found in the headspace of drums containing TRU waste. It is not known whether the volatile organic compounds (VOCs) commonly found in the headspace of TRU waste drums will inhibit (poison) the effectiveness of the hydrogen getter. The results of this study will be used to assess the feasibility of a hydrogen-getter system, which is capable of removing hydrogen from the payload containers or the Transuranic Package Transporter-II (TRUPACT-II) inner containment vessel to increase the quantity of TRU waste that can be shipped to the WIPP.

  4. Hydrogen isotope separation utilizing bulk getters

    DOEpatents

    Knize, Randall J.; Cecchi, Joseph L.

    1990-01-01

    Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last-mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen.

  5. Hydrogen isotope separation utilizing bulk getters

    DOEpatents

    Knize, Randall J.; Cecchi, Joseph L.

    1991-01-01

    Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last-mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen.

  6. Hydrogen isotope separation utilizing bulk getters

    DOEpatents

    Knize, R.J.; Cecchi, J.L.

    1991-08-20

    Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last-mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen. 4 figures.

  7. An issue paper on the use of hydrogen getters in transportation packaging

    SciTech Connect

    NIGREY,PAUL J.

    2000-02-01

    The accumulation of hydrogen is usually an undesirable occurrence because buildup in sealed systems pose explosion hazards under certain conditions. Hydrogen scavengers, or getters, can avert these problems by removing hydrogen from such environments. This paper provides a review of a number of reversible and irreversible getters that potentially could be used to reduce the buildup of hydrogen gas in containers for the transport of radioactive materials. In addition to describing getters that have already been used for such purposes, novel getters that might find application in future transport packages are also discussed. This paper also discusses getter material poisoning, the use of getters in packaging, the effects of radiation on getters, the compatibility of getters with packaging, design considerations, regulatory precedents, and makes general recommendations for the materials that have the greatest applicability in transport packaging. At this time, the Pacific Northwest National Laboratory composite getter, DEB [1,4-(phenylethylene)benzene] or similar polymer-based getters, and a manganese dioxide-based getter appear to be attractive candidates that should be further evaluated. These getters potentially can help prevent pressurization from radiolytic reactions in transportation packaging.

  8. Polymer formulations for gettering hydrogen

    DOEpatents

    Shepodd, Timothy J.; Even, Jr., William R.

    2000-01-01

    A novel method for preparing a hydrogenation composition comprising organic polymer molecules having carbon--carbon double bonds, for removing hydrogen from the atmosphere within enclosed spaces and particularly from atmospheres within enclosed spaces that contain air, water vapor, oxygen, carbon dioxide or ammonia. The organic polymers molecules containing carbon--carbon double bonds throughout their structures, preferably polybutadiene, polyisoprene and derivatives thereof, intimately mixed with an insoluble noble metal catalyst composition. High molecular weight polymers may be added to the organic polymer/catalyst mixture in order to improve their high temperature performance. The hydrogenation composition is prepared by dispersing the polymers in a suitable solvent, forming thereby a solution suspension, flash-freezing droplets of the solution in a liquid cryogen, freeze-drying the frozen droplets to remove frozen solvent incorporated in the droplets, and recovering the dried powder thus formed.

  9. Method for absorbing hydrogen using an oxidation resisant organic hydrogen getter

    DOEpatents

    Shepodd, Timothy J.; Buffleben, George M.

    2009-02-03

    A composition for removing hydrogen from an atmosphere, comprising a mixture of a polyphenyl ether and a hydrogenation catalyst, preferably a precious metal catalyst, and most preferably platinum, is disclosed. This composition is stable in the presence of oxygen, will not polymerize or degrade upon exposure to temperatures in excess of 200.degree. C., or prolonged exposure to temperatures in the range of 100-300.degree. C. Moreover, these novel hydrogen getter materials can be used to efficiently remove hydrogen from mixtures of hydrogen/inert gas (e.g., He, Ar, N.sub.2), hydrogen/ammonia atmospheres, such as may be encountered in heat exchangers, and hydrogen/carbon dioxide atmospheres. Water vapor and common atmospheric gases have no adverse effect on the ability of these getter materials to absorb hydrogen.

  10. Hydrogen gettering packing material, and process for making same

    DOEpatents

    LeMay, James D.; Thompson, Lisa M.; Smith, Henry Michael; Schicker, James R.

    2001-01-01

    A hydrogen gettering system for a sealed container is disclosed comprising packing material for use within the sealed container, and a coating film containing hydrogen gettering material on at least a portion of the surface of such packing material. The coating film containing the hydrogen gettering material comprises a mixture of one or more organic materials capable of reacting with hydrogen and one or more catalysts capable of catalyzing the reaction of hydrogen with such one or more organic materials. The mixture of one or more organic materials capable of reacting with hydrogen and the one or more catalysts is dispersed in a suitable carrier which preferably is a curable film-forming material. In a preferred embodiment, the packing material comprises a foam material which is compatible with the coating film containing hydrogen gettering material thereon.

  11. Hydrogen gettering packing material and process for making same

    SciTech Connect

    LeMay, James D.; Thompson, Lisa M.; Smith, Henry Michael; Schicker, James R.

    1999-09-09

    A hydrogen gettering system for a sealed container is disclosed comprising packing material for use within the sealed container, and a coating film containing hydrogen gettering material on at least a portion of the surface of such packing material. The coating film containing the hydrogen gettering material comprises a mixture of one or more organic materials capable of reacting with hydrogen and one or more catalysts capable of catalyzing the reaction of hydrogen with such one or more organic materials. The mixture of one or more organic materials capable of reacting with hydrogen and the one or more catalysts is dispersed in a suitable carrier which preferably is a curable film-forming material. In a preferred embodiment, the packing material comprises a foam material which is compatible with the coating film containing hydrogen gettering material thereon.

  12. Test Plan for Composite Hydrogen Getter Materials

    SciTech Connect

    Livingston, R.R.

    2000-11-09

    The intent of this test plan is to provide details of the Savannah River Technology Center (SRTC) effort to evaluate composite getter materials for eventual use in expanding the wattage limits for transportation of contact-handled transuranic waste (CH-TRU). This effort is funded by the Mixed Waste Focus Area (MWFA) under Technical Task Plan (TTP) SR-1-9-MW-45 and is the result of a competitive process initiated by a MWFA request for proposals. In response to this request, SRTC presented data on several composite getter materials that demonstrated good potential for application in transportation of transuranic wastes. The tests outlined in the SRTC proposal for composite getter materials should demonstrate compliance with functional requirements provided by the MWFA in a Statement of Work (SOW) which accompanied the request for proposals. Completion of Phase 1 testing, as defined in the TTP, should provide sufficient data to determine if composite getters should progress to Phase s 2 and 3. These test results will provide support for future safety reviews as part of the Transuranic Package Transporter-II (TRUPACT-II) certification process to utilize getter technology. This test plan provides details of the test descriptions, test objectives, required measurements, data quality objectives, data analysis, and schedule information relevant to Phase 1 of the TTP. The results of these tests are expected to help identify any potential weaknesses in the use of composite getter for transportation of CH-TRU wastes. Where a potential weakness is identified, this will be addressed as part of Phase 2 of the proposed effort. It is also important to recognize that these tests are focused on the individual composite getter materials and not the engineered system that would eventually be used in a TRUPACT-II. However, these test results will be very helpful in establishing the requirements for the design of a TRUPACT-II getter system that is included as part of the propo sed Phase

  13. USE OF HYDROGEN GETTERS FOR ENSURING SAFE STORAGE OF PLUTONIUM-BEARING MATERIALS AT THE SAVANNAH RIVER SITE

    SciTech Connect

    Woodsmall, T.; Hackney, B.; Traver, L.

    2010-05-20

    Plutonium oxide left over from the 3013 destructive surveillance process is ultimately disposed of as waste. Therefore, this material is not re-stabilized and packaged to meet the requirements of DOE-STD-3013. Instead, it is stored on an interim basis in compliance with the interim safe storage criteria issued by DOE in January 1996. One of the safe storage criteria requires actions to be taken to minimize the formation or accumulation of flammable gases inside the storage container. Personnel responsible for the safe storage of the material have chosen to use a polymer-based, ambient air compatible hydrogen 'getter' to prevent the formation of hydrogen gas inside the storage container and thus prevent the formation of a flammable gas mixture. This paper briefly describes the method in which the getter performs its functions. More importantly, this paper presents the results of the testing that has been performed to characterize the bounding effects of aging and demonstrate the use of the getter for long-term storage. In addition, the favorable results of a post-storage analysis of actual getter material are presented and compared with bounding predictions. To date, bounding test results have shown that after 18 months of continuous storage and 39 months of total storage at 70C, the getter is able to both recombine gaseous hydrogen and oxygen into water when oxygen is available, and irreversibly getter (i.e., scavenge) hydrogen from the vapor space when oxygen is not available, both under a CO{sub 2} environment. Further bounding testing has been deemed unnecessary, and continued post-storage testing will be conducted on a periodic basis. The first post-storage testing of deployed getter material after two years of service revealed that it still performed like new material.

  14. USING POLYMERIC HYDROGEN GETTERS TO PREVENT COMBUSTIBLE ATMOSPHERES DURING INTERIM SAFE STORAGE OF PLUTONIUM OXIDE

    SciTech Connect

    Woodsmall, T

    2007-05-24

    Nuclear Materials Management (NMM) of WSRC has recently installed the capability to perform both non-destructive and destructive examination of 3013 containers of Pu oxide in accordance with DOE-STD-3013. The containers will be opened and the oxide will be sampled for analysis. The remaining bulk oxide must then be safely stored in a non-3013-compliant configuration. Available processing equipment and controls cannot prevent the oxide from adsorbing moisture during this process. Subsequent radiolysis of moisture during storage may generate combustible quantities of gases while waiting final processing, and satisfying DOE Interim Safe Storage Criteria (ISSC) would require that storage containers be vented at impractical frequencies. With support from an independent National Laboratory, WSRC/NMM has demonstrated that a commercial hydrogen getter material will effectively prevent the accumulation of combustible gas concentrations. A project overview, including storage requirements and strategies, as well as getter technology, current test results, and anticipated future developments will be addressed.

  15. DPB hydrogen getters on Pd (110) - its action and the effect of impurities

    SciTech Connect

    Maiti, A; Gee, R

    2005-03-11

    Density Functional Theory (DFT) is used to investigate the action of hydrogen getter 1,4-diphenyl-butadiyne, or DPB, on Pd(110) surface. We study reaction pathways and energetics of several relevant processes, including H{sub 2} adsorption, dissociation and migration on the metal surface, getter-metal interaction, and the energetics of H uptake by the getter. We also explore the effect of impurities like CO and CO{sub 2} on the action of the getter. Activation barriers for certain reactions are computed to shed light on the feasibility of such processes at room temperature.

  16. Performance testing of aged hydrogen getters against criteria for interim safe storage of plutonium bearing materials.

    SciTech Connect

    Shepodd, Timothy J.; Nissen, April; Buffleben, George M.

    2006-01-01

    Hydrogen getters were tested for use in storage of plutonium-bearing materials in accordance with DOE's Criteria for Interim Safe Storage of Plutonium Bearing Materials. The hydrogen getter HITOP was aged for 3 months at 70 C and tested under both recombination and hydrogenation conditions at 20 and 70 C; partially saturated and irradiated aged getter samples were also tested. The recombination reaction was found to be very fast and well above the required rate of 45 std. cc H2h. The gettering reaction, which is planned as the backup reaction in this deployment, is slower and may not meet the requirements alone. Pressure drop measurements and {sup 1}H NMR analyses support these conclusions. Although the experimental conditions do not exactly replicate the deployment conditions, the results of our conservative experiments are clear: the aged getter shows sufficient reactivity to maintain hydrogen concentrations below the flammability limit, between the minimum and maximum deployment temperatures, for three months. The flammability risk is further reduced by the removal of oxygen through the recombination reaction. Neither radiation exposure nor thermal aging sufficiently degrades the getter to be a concern. Future testing to evaluate performance for longer aging periods is in progress.

  17. Hydrogen capacity and absorption rate of the SAES St707 non-evaporable getter at various temperatures.

    SciTech Connect

    Hsu, Irving; Mills, Bernice E.

    2010-08-01

    A prototype of a tritium thermoelectric generator (TTG) is currently being developed at Sandia. In the TTG, a vacuum jacket reduces the amount of heat lost from the high temperature source via convection. However, outgassing presents challenges to maintaining a vacuum for many years. Getters are chemically active substances that scavenge residual gases in a vacuum system. In order to maintain the vacuum jacket at approximately 1.0 x 10{sup -4} torr for decades, nonevaporable getters that can operate from -55 C to 60 C are going to be used. This paper focuses on the hydrogen capacity and absorption rate of the St707{trademark} non-evaporable getter by SAES. Using a getter testing manifold, we have carried out experiments to test these characteristics of the getter over the temperature range of -77 C to 60 C. The results from this study can be used to size the getter appropriately.

  18. New High Capacity Getter for Vacuum-Insulated Mobile Liquid Hydrogen Storage Systems

    SciTech Connect

    H. Londer; G. R. Myneni; P. Adderley; G. Bartlok; J. Setina; W. Knapp; D. Schleussner

    2006-05-01

    Current ''Non evaporable getters'' (NEGs), based on the principle of metallic surface sorption of gas molecules, are important tools for the improving the performance of many vacuum systems. High porosity alloys or powder mixtures of Zr, Ti, Al, V, Fe and other metals are the base materials for this type of getters. The continuous development of vacuum technologies has created new challenges for the field of getter materials. The main sorption parameters of the current NEGs, namely, pumping speed and sorption capacity, have reached certain upper limits. Chemically active metals are the basis of a new generation of NEGs. The introduction of these new materials with high sorption capacity at room temperature is a long-awaited development. These new materials enable the new generation of NEGs to reach faster pumping speeds, significantly higher sticking rates and sorption capacities up to 104 times higher during their lifetimes. Our development efforts focus on producing these chemically active metals with controlled insulation or protection. The main structural forms of our new getter materials are spherical powders, granules and porous multi-layers. The full pumping performance can take place at room temperature with activation temperatures ranging from room temperature to 650 C. In one of our first pilot projects, our proprietary getter solution was successfully introduced as a getter pump in a double-wall mobile LH2 tank system. Our getters were shown to have very high sorption capacity of all relevant residual gases, including H2. This new concept opens the opportunity for significant vacuum improvements, especially in the field of H2 pumping which is an important task in many different vacuum applications.

  19. Effect of hydrogen glow discharge conditioning on Zr/Al getter pumps

    SciTech Connect

    Dylla, H.F.; Cecchi, J.L.; Ulrickson, M.

    1981-01-01

    Zr/Al bulk getter pumps are presently being considered for use in the Tokamak Fusion Test Reactor (TFTR) to reduce impurities and limit the recycling of hydrogenic species. It is necessary that these pumps not be adversely affected by the hydrogen glow discharge cleaning (GDC) which is planned as part of the routine TFTR vessel wall conditioning. The GDC procedure involves the use of a dc glow discharge with a 400 V bias voltage. The total fluence of hydrogenic ions given to the affected surfaces during a typical conditioning period is 10/sup 18/ cm/sup -2/. We have investigated the effects of typical GDC runs on a getter-pump module containing 25 g of Zr/Al mounted in a 100 liter test stand. Pumping speed, capacity, and regeneration characteristics have been studied after various exposures to GDC.

  20. Studies of chromium gettering

    SciTech Connect

    Simpkins, J.E.; Mioduszewski, P.; Stratton, L.W.

    1982-01-01

    Preliminary results have shown that hydrogen pumping by chromium is a surface effect. Unlike with titanium, the getter material used in many present day tokamaks, there is no significant diffusion into the bulk. Additional experiments have been carried out to measure the basic characteristics of chromium films for gases of interest in tokamak research. These gases include deuterium, oxygen and nitrogen. A vacuum system is described which allowed precise control of the test gas, a constant wall temperature and determination of the projected getter surface area. A quadrupole mass spectrometer, rather than simply a total pressure gauge, was utilized to measure the partial pressure of the test gas as well as the residual gas composition in the system. A quartz crystal monitor was used to measure film thickness. Pumping speeds and sticking coefficients are given as a function of surface coverage for each test gas. A comparison will be made with titanium films deposited in the same vacuum system and under similar conditions.

  1. Engineering Report on the Fission Gas Getter Concept

    SciTech Connect

    Ecker, Lynne; Ghose, Sanjit; Gill, Simerjeet; Thallapally, Praveen K.; Strachan, Denis M.

    2012-11-01

    In 2010, the Department of Energy (DOE) requested that a Brookhaven National Laboratory (BNL)-led team research the possibility of using a getter material to reduce the pressure in the plenum region of a light water reactor fuel rod. During the first two years of the project, several candidate materials were identified and tested using a variety of experimental techniques, most with xenon as a simulant for fission products. Earlier promising results for candidate getter materials were found to be incorrect, caused by poor experimental techniques. In May 2012, it had become clear that none of the initial materials had demonstrated the ability to adsorb xenon in the quantities and under the conditions needed. Moreover, the proposed corrective action plan could not meet the schedule needed by the project manager. BNL initiated an internal project review which examined three questions: 1. Which materials, based on accepted materials models, might be capable of absorbing xenon? 2. Which experimental techniques are capable of not only detecting if xenon has been absorbed but also determine by what mechanism and the resulting molecular structure? 3. Are the results from the previous techniques useable now and in the future? As part of the second question, the project review team evaluated the previous experimental technique to determine why incorrect results were reported in early 2012. This engineering report is a summary of the current status of the project review, description of newly recommended experiments and results from feasibility studies at the National Synchrotron Light Source (NSLS).

  2. Characterization Of The Hydrogenation Products Of Bix (phenylethynyl) Benzene (DEB) Getter Using Combined GC/FTIR/MS, FT-Raman, and ATR Spectroscopies (U)

    SciTech Connect

    Smyrl, N. R.; Powell, G. L.

    2011-06-09

    Organic hydrogen getters are utilized to minimize hydrogen accumulation in sealed systems where such build up could produce either a safety problem from pressure build up or corrosion problem due the hydriding of metals contained in the sealed vessel. DEB (1,4 bis (phenyl ethynyl) benzene) is a hydrogen getter that is based on the palladium catalyzed hydrogenation of triple bonds to single bonds in aromatic aryl compound. DEB is a getter mixed with 25% carbon and 1% Pd and pressed into pellets with some porosity. The reaction mechanisms are complex involving solid state reactions with a heterogeneous catalyst leading to the many intermediates.

  3. Evaluation of RTV as a Moldable Matrix When Combined With Molecular Sieve and Organic Hydrogen Getter

    SciTech Connect

    Knight, J. A.

    2011-12-01

    This work was undertaken in an effort to develop a combined RTV 615/3Å molecular sieve/DEB molded component. A molded RTV 615/3Å molecular sieve component is currently in production, and an RTV 615/DEB component was produced in the past. However, all three materials have never before been combined in a single production part, and this is an opportunity to create a new component capable of being molded to shape, performing desiccation, and hydrogen gettering. This analysis looked at weapons system parameters and how they might influence part design. It also looked at material processing and how it related to mixing, activating a dessicant, and hydrogen uptake testing.

  4. Gas handling systems using titanium-sponge and uranium bulk getters

    SciTech Connect

    Kherani, N.P.; Shmayda, W.T.

    1985-09-01

    A protium gas handling system using titanium and uranium bulk getters was designed, constructed and tested. Numerous process operations were carried out on this system to aid in the design of a tritium gas handling system four times the experimental scale. Experimental results have shown that high percentages of tritium on long-term titanium storage beds can be recovered in a relatively short period of time and be transferred to uranium bed(s) in direct (pump-less) and pump-aided transfers. An optimum storage time after which the rate of interstitial /sup 3/He evolution would be prohibitive to conduct direct tritium transfers is estimated.

  5. The separation and characterization of a hydrogen getter product mixture: Part 2, measurement of product vapor pressures

    SciTech Connect

    Fircish, D.W.; Shell, T.R.

    1987-06-04

    HCPB is the acronym of an organic hydrogen getter compound used in weapon systems. When this material scavenges hydrogen by reacting with it, a number of compounds are formed, each of which is more volatile than HCPB. It is desirable to know the vapor pressure of these products in order to assess their migration potential within the weapon. In this study, individual compounds from a reacted HCPB mixture were isolated and their vapor pressures were measured. Three of the four fractions examined with a modified capacitance manometer were found to have vapor pressures under 1 mtorr; the fourth was measured at 92 +- 15 mtorr. An attempt was made to obtain boiling point data on the two liquid components of the getter mixture, but they decomposed before reaching their boiling points.

  6. Bulk lifetime and efficiency enhancement due to gettering and hydrogenation of defects during cast multicrystalline silicon solar cell fabrication

    NASA Astrophysics Data System (ADS)

    Sheoran, Manav; Upadhyaya, Ajay; Rohatgi, Ajeet

    2008-05-01

    Cast multicrystalline silicon (mc-Si) shows a significant variation in quality depending on the location of the brick in the ingot and the location of the wafer in the brick. Variation also occurs in ingots from different suppliers, which is attributed to the difference in the cleanliness of the crucible used for growth and the quality of the silicon feedstock used. Process-induced lifetime investigation conducted in this paper showed that wafers from the top region of mc-Si ingot grown by Heat Exchanger Method (HEM) benefited most from the gettering step during phosphorus diffusion to form the n + junction. Wafers from the bottom of the ingot, however, benefited most from the hydrogenation taking place from the SiN x film during the co-firing cycle used to form simultaneous front and back contacts and aluminum back surface field. Wafers from the middle region benefited from both, the diffusion-gettering, and the SiN x-hydrogenation. Un-textured, 4 cm 2, screen-printed, best solar cell efficiencies of 15.9% and above were achieved on wafers from top, middle, and bottom regions of most of the ingots used in this study because the bulk lifetime exceeded 100 μs after gettering and hydrogenation. Lifetimes in excess of 300 μs were achieved from the middle region of some mc-Si ingots. Solar cell efficiencies of 16.7% were attained from the middle regions of two out of the three ingots investigated in this study. Device modeling was performed to provide guidelines to reduce the efficiency variation across different regions of the ingots and to obtain the highest possible efficiency with a given bulk lifetime and device structure.

  7. Impurity and recycling control with gettering in ATF

    SciTech Connect

    Simpkins, J.E.; Mioduszewski, P.K.; Isler, R.C.

    1991-01-01

    The vacuum vessel of the Advanced Toroidal Facility (ATF) is Ti-gettered with a surface coverage of 70%. The major effects of gettering are: (1) reduction of the oxygen, carbon, and nitrogen content in the plasma and (2) improved density control due to wall pumping of the working gas hydrogen. The overall leak rate in ATF is 2{times}10{sup {minus}4} Torr-l/s which is too high for successful plasma operation. Ti-gettering is routinely employed every morning prior to operation and compensates for this shortcoming by reducing the partial pressure of nitrogen and other residual gas components to the low 10{sup {minus}9} Torr range which is close to the RGA background pressure. Rate-of-rise measurements at this stage show only argon and some methane. The argon is used to monitor the leak rate. In addition to impurity reduction, gettering leads to low recycling of the working gas which appears to be crucial for density control in ATF. The capacity of the gettered surface is large enough to show a strong effect even after 24 hours. An extensive data base on the short-term and long-term effects of gettering on the residual gas composition and its effects on plasma performance has been established over the past three years and will be discussed in this paper. 9 refs., 7 figs.

  8. Impurity gettering

    SciTech Connect

    Picraux, S.T.

    1995-06-01

    Transition metal impurities are well known to cause detrimental effects when present in the active regions of Si devices. Their presence degrades minority carrier lifetime, provides recombination-generation centers, increases junction leakage current and reduces gate oxide integrity. Thus, gettering processes are used to reduce the available metal impurities from the active region of microelectronic circuits. Gettering processes are usually divided into intrinsic (or internal) and extrinsic (or external) categories. Intrinsic refers to processing the Si wafer in a way to make available internal gettering sites, whereas extrinsic implies externally introduced gettering sites. Special concerns have been raised for intrinsic gettering. Not only will the formation of the precipitated oxide and denuded zone be difficult to achieve with the lower thermal budgets, but another inherent limit may set in. In this or any process which relies on the precipitation of metal silicides the impurity concentration can only be reduced as low as the solid solubility limit. However, the solubilities of transition metals relative to silicide formation are typically found to be {approx_gt}10{sup 12}/cm{sup 3} at temperatures of 800 C and above, and thus inadequate to getter to the needed concentration levels. It is thus anticipated that future microelectronic device processing will require one or more of the following advances in gettering technology: (1) new and more effective gettering mechanisms; (2) quantitative models of gettering to allow process optimization at low process thermal budgets and metal impurity concentrations, and/or (3) development of front side gettering methods to allow for more efficient gettering close to device regions. These trend-driven needs provide a driving force for qualitatively new approaches to gettering and provide possible new opportunities for the use of ion implantation in microelectronics processing.

  9. Deposition and Characterization of Improved Hydrogen Getter Materials - Report on FY 14-15 Activities

    SciTech Connect

    Hubbard, Kevin Mark; Sandoval, Cynthia Wathen

    2015-10-15

    The goals of this work have been two-fold. First, to perform an initial, quantitative, optimization of getter performance, with the primary variables being DEB/Pd ratio and UV power. Second, to simplify the deposition process to make it more compatible with the DOE production environment.

  10. Hydrogen rich gas generator

    NASA Technical Reports Server (NTRS)

    Houseman, J. (Inventor)

    1976-01-01

    A process and apparatus is described for producing a hydrogen rich gas by introducing a liquid hydrocarbon fuel in the form of a spray into a partial oxidation region and mixing with a mixture of steam and air that is preheated by indirect heat exchange with the formed hydrogen rich gas, igniting the hydrocarbon fuel spray mixed with the preheated mixture of steam and air within the partial oxidation region to form a hydrogen rich gas.

  11. Metal getters for tritium storage

    SciTech Connect

    Willin, E.; Sirch, M.; Penzhorn, R.D.; Devillers, M.

    1988-09-01

    Whereas titanium is a getter material mainly suitable for the long-term storage of tritium, zirconium cobalt alloy can also be employed for the interim storage and transport of this gas. Activated zirconium cobalt alloy reacts within minutes with hydrogen at room temperature. At the composition of /ZrCoH/sub 0.8/ the dissociation pressure at room temperature is estimated to be 10/sup -3/ Pa. The zirconium cobalt/H/sub 2/ system is not pyrophoric at room temperature. Methane is partially cracked on Ti and on ZrCo at temperatures above 600 and 300/sup 0/C respectively. With titanium the corresponding carbide is formed without affecting the storage properties of the getter. After reaction of ZrCo with CH/sub 4/ or N/sub 2/ the hydrogen adsorption capacity is reduced. Titanium powder, sponge or sheet react with nitrogen at temperatures above 750/sup 0/C with a parabolic rate law. In the overlayer of the metal substrate the phases N dissolved in /alpha/-Ti, Ti/sub 2/N and TiN were identified. The same phases were observed when NH/sub 3/ reacts with this metal.

  12. Hydrogen rich gas generator

    NASA Technical Reports Server (NTRS)

    Houseman, J.; Rupe, J. H.; Kushida, R. O. (Inventor)

    1976-01-01

    A process and apparatus is described for producing a hydrogen rich gas by injecting air and hydrocarbon fuel at one end of a cylindrically shaped chamber to form a mixture and igniting the mixture to provide hot combustion gases by partial oxidation of the hydrocarbon fuel. The combustion gases move away from the ignition region to another region where water is injected to be turned into steam by the hot combustion gases. The steam which is formed mixes with the hot gases to yield a uniform hot gas whereby a steam reforming reaction with the hydrocarbon fuel takes place to produce a hydrogen rich gas.

  13. DNA-base guanine as hydrogen getter and charge-trapping layer embedded in oxide dielectrics for inorganic and organic field-effect transistors.

    PubMed

    Lee, Junyeong; Park, Ji Hoon; Lee, Young Tack; Jeon, Pyo Jin; Lee, Hee Sung; Nam, Seung Hee; Yi, Yeonjin; Lee, Younjoo; Im, Seongil

    2014-04-01

    DNA-base small molecules of guanine, cytosine, adenine, and thymine construct the DNA double helix structure with hydrogen bonding, and they possess such a variety of intrinsic benefits as natural plentitude, biodegradability, biofunctionality, low cost, and low toxicity. On the basis of these advantages, here, we report on unprecedented useful applications of guanine layer as hydrogen getter and charge trapping layer when it is embedded into a dielectric oxide of n-channel inorganic InGaZnO and p-channel organic heptazole field effect transistors (FETs). The embedded guanine layer much improved the gate stability of inorganic FETs gettering many hydrogen atoms in the gate dielectric layer of FET, and it also played as charge trapping layer to which the voltage pulse-driven charges might be injected from channel, resulting in a threshold voltage (Vth) shift of FETs. Such shift state is very ambient-stable and almost irrevocable even under a high electric-field at room temperature. So, Boolean logics are nicely demonstrated by using our FETs with the guanine-embedded dielectric. The original Vth is recovered only under high energy blue photons by opposite voltage pulse (charge-ejection), which indicates that our device is also applicable to nonvolatile photo memory.

  14. Impurity gettering in semiconductors

    DOEpatents

    Sopori, B.L.

    1995-06-20

    A process for impurity gettering in a semiconductor substrate or device such as a silicon substrate or device is disclosed. The process comprises hydrogenating the substrate or device at the back side thereof with sufficient intensity and for a time period sufficient to produce a damaged back side. Thereafter, the substrate or device is illuminated with electromagnetic radiation at an intensity and for a time period sufficient to cause the impurities to diffuse to the back side and alloy with a metal there present to form a contact and capture the impurities. The impurity gettering process also can function to simultaneously passivate defects within the substrate or device, with the defects likewise diffusing to the back side for simultaneous passivation. Simultaneously, substantially all hydrogen-induced damage on the back side of the substrate or device is likewise annihilated. Also taught is an alternate process comprising thermal treatment after hydrogenation of the substrate or device at a temperature of from about 500 C to about 700 C for a time period sufficient to cause the impurities to diffuse to the damaged back side thereof for subsequent capture by an alloying metal. 1 fig.

  15. MECHANICAL ALLOYING AND THERMAL TREATMENT FOR PRODUCTION OF ZIRCONIUM IRON HYDROGEN ISOTOPE GETTERS

    SciTech Connect

    Fox, K.

    2008-02-20

    The objective of this task was to demonstrate that metal hydrides could be produced by mechanical alloying in the quantities needed to support production-scale hydrogen isotope separations. Three starting compositions (ratios of elemental Zr and Fe powders) were selected and attritor milled under argon for times of 8 to 60 hours. In general, milling times of at least 24 hours were required to form the desired Zr{sub 2}Fe and Zr{sub 3}Fe phases, although a considerable amount of unalloyed Zr and Fe remained. Milling in liquid nitrogen does not appear to provide any advantages over milling in hexane, particularly due to the formation of ZrN after longer milling times. Carbides of Zr formed during some of the milling experiments in hexane. Elemental Zr was present in the as-milled material but not detected after annealing for milling times of 48 and 60 hours. It may be that after intimate mixing of the powders in the attritor mill the annealing temperature was sufficient to allow for the formation of a Zr-Fe alloy. Further investigation of this conversion is necessary, and could provide an opportunity for reducing the amount of unreacted metal powder after milling.

  16. Gas controlled hydrogen fermentation.

    PubMed

    Bastidas-Oyanedel, Juan-Rodrigo; Mohd-Zaki, Zuhaida; Zeng, Raymond J; Bernet, Nicolas; Pratt, Steven; Steyer, Jean-Philippe; Batstone, Damien John

    2012-04-01

    Acidogenic fermentation is an anaerobic process of double purpose, while treating organic residues it produces chemical compounds, such as hydrogen, ethanol and organic acids. Therefore, acidogenic fermentation arises as an attractive biotechnology process towards the biorefinery concept. Moreover, this process does not need sterile operating conditions and works under a wide range of pH. Changes of operating conditions produce metabolic shifts, inducing variability on acidogenic product yield. To induce those changes, experiments, based on reactor headspace N(2)-flushing (gas phase), were designed. A major result was the hydrogen yield increase from 1 to 3.25±0.4 ( [Formula: see text] ) at pH 4.5 and N(2)-flushing of 58.4 (L·d(-1)). This yield is close to the theoretical acidogenic value (4 [Formula: see text] ). The mechanisms that explain this increase on hydrogen yield shifts are related to the thermodynamics of three metabolic reactions: lactate hydrogenase, NADH hydrogenase and homoacetogenesis, which are affected by the low hydrogen partial pressures. PMID:22342590

  17. Radiolytic Bubble Gas Hydrogen Compositions

    SciTech Connect

    Hester, J.R.

    2003-02-05

    Radioactive waste solids can trap bubbles containing hydrogen that may pose a flammability risk if they are disturbed and hydrogen is released. Whether a release is a problem or not depends, among other things, on the hydrogen composition of the gas. This report develops a method for estimating the hydrogen composition of trapped bubbles based on waste properties.

  18. Radiolytic Bubble Gas Hydrogen Compositions

    SciTech Connect

    Hester, J.R.

    2001-08-28

    Radioactive waste solids can trap bubbles containing hydrogen that may pose a flammability risk if they are disturbed and hydrogen is released. Whether a release is a problem or not depends, among other things, on the hydrogen composition of the gas. This report develops a method for estimating the hydrogen composition of trapped bubbles based on waste properties.

  19. Materials for the scavanging of hydrogen at high temperatures

    DOEpatents

    Shepodd, Timothy J.; Phillip, Bradley L.

    1997-01-01

    A hydrogen getter composition comprising a double or triple bonded hydrocarbon with a high melting point useful for removing hydrogen gas, to partial pressures below 0.01 torr, from enclosed spaces and particularly from vessels used for transporting or containing fluids at elevated temperatures. The hydrogen getter compositions disclosed herein and their reaction products will neither melt nor char at temperatures in excess of 100.degree. C. They possess significant advantages over conventional hydrogen getters, namely low risk of fire or explosion, no requirement for high temperature activation or operation, the ability to absorb hydrogen even in the presence of contaminants such as water, water vapor, common atmospheric gases and oil mists and are designed to be disposed within the confines of the apparatus. These getter materials can be mixed with binders, such as fluropolymers, which permit the getter material to be fabricated into useful shapes and/or impart desirable properties such as water repellency or impermeability to various gases.

  20. Materials for the scavanging of hydrogen at high temperatures

    DOEpatents

    Shepodd, Timothy J.; Phillip, Bradley L.

    1997-01-01

    A hydrogen getter composition comprising a double or triple bonded hydrocarbon with a high melting point useful for removing hydrogen gas, to partial pressures below 0.01 torr, from enclosed spaces and particularly from vessels used for transporting or containing fluids at elevated temperatures. The hydrogen getter compostions disclosed herein and their reaction products will neither melt nor char at temperatures in excess of 100C. They possess significant advantages over conventional hydrogen getters, namely low risk of fire or explosion, no requirement for high temperature activation or operation, the ability to absorb hydrogen even in the presence of contaminants such as water, water vapor, common atmospheric gases and oil mists and are designed to be disposed within the confines of the apparatus. These getter materials can be mixed with binders, such as fluropolymers, which permit the getter material to be fabricated into useful shapes and/or impart desirable properties such as water repellency or impermeability to various gases.

  1. Sensitive hydrogen leak detector

    DOEpatents

    Myneni, G.R.

    1999-08-03

    A sensitive hydrogen leak detector system is described which uses passivation of a stainless steel vacuum chamber for low hydrogen outgassing, a high compression ratio vacuum system, a getter operating at 77.5 K and a residual gas analyzer as a quantitative hydrogen sensor. 1 fig.

  2. Sensitive hydrogen leak detector

    DOEpatents

    Myneni, Ganapati Rao

    1999-01-01

    A sensitive hydrogen leak detector system using passivation of a stainless steel vacuum chamber for low hydrogen outgassing, a high compression ratio vacuum system, a getter operating at 77.5 K and a residual gas analyzer as a quantitative hydrogen sensor.

  3. Porous silicon gettering

    SciTech Connect

    Tsuo, Y.S.; Menna, P.; Pitts, J.R.

    1996-05-01

    The authors have studied a novel extrinsic gettering method that uses the large surface areas produced by a porous-silicon etch as gettering sites. The annealing step of the gettering used a high-flux solar furnace. They found that a high density of photons during annealing enhanced the impurity diffusion to the gettering sites. The authors used metallurgical-grade Si (MG-Si) prepared by directional solidification casing as the starting material. They propose to use porous-silicon-gettered MG-Si as a low-cost epitaxial substrate for polycrystalline silicon thin-film growth.

  4. Porous silicon gettering

    SciTech Connect

    Tsuo, Y.S.; Menna, P.; Al-Jassim, M.

    1995-08-01

    We have studied a novel extrinsic gettering method that utilizes the very large surface areas, produced by porous silicon etch on both front and back surfaces of the silicon wafer, as gettering sites. In this method, a simple and low-cost chemical etching is used to generate the porous silicon layers. Then, a high-flux solar furnace (HFSF) is used to provide high-temperature annealing and the required injection of silicon interstitials. The gettering sites, along with the gettered impurities, can be easily removed at the end the process. The porous silicon removal process consists of oxidizing the porous silicon near the end the gettering process followed by sample immersion in HF acid. Each porous silicon gettering process removes up to about 10 {mu}m of wafer thickness. This gettering process can be repeated so that the desired purity level is obtained.

  5. Resistance projection welding of vacuum tube getter assembly

    SciTech Connect

    Kuncz, F. Jr.

    1980-12-10

    Tungsten inert gas welding the leads to a vacuum tube getter assembly can result in fusion of gettering powder, lowering gas absorption capability. Using resistance projection welding with ball-ended leads, getter bodies were successfully bonded to the leads. Special electrodes were designed. Materials and methods are given for producing ball-ended leads, designating and building special electrodes, and for welding the leads to the body.

  6. Evolution of gettering technologies for vacuum tubes to getters for MEMS

    NASA Astrophysics Data System (ADS)

    Amiotti, M.

    2008-05-01

    Getter materials are technically proven and industrially accepted practical ways to maintain vacuum inside hermetically sealed tubes or devices to assure high reliability and long lifetime of the operating devices. The most industrially proven vacuum tube is the cathode rays tubes (CRTs), where large surfaces are available for the deposition of an evaporated barium film by a radio frequency inductive heating of a stainless steel container filled with a BaAl4 powder mixed to Ni powder. The evolution of the CRTs manufacturing technologies required also new types of barium getters able to withstand some thermal process in air without any deterioration of the evaporation characteristics. In other vacuum tubes such as traveling waves tubes, the space available for the evaporation of a barium film and the sorption capacity required to assure the vacuum for the lifetime of the devices did not allow the use of the barium film, prompting the development of sintered non evaporable getter pills that can be activated during the manufacturing process or by flowing current through an embedded resistance. The same sintered non evaporable getter pills could find usage also in evacuated parts to thermally isolate the infrared sensors for different final applications. In high energy physics particle accelerators, the getter technology moved from localized vacuum getter pumps or getter strips to a getter coating over the surface of vacuum chambers in order to guarantee a more uniform pumping speed. With the advent of solid state electronics, new challenges faced the getter technology to assure long life to vacuum or inert gas filled hermetical packages containing microelectronic devices, especially in the telecommunication and military applications. A well known problem of GaAs devices with Pd or Pt metalization is the H2 poisoning of the metal gate: to prevent this degradation a two layer getter film has been develop to absorb a large quantity of H2 per unit of getter surface. The

  7. Composition for absorbing hydrogen from gas mixtures

    DOEpatents

    Heung, Leung K.; Wicks, George G.; Lee, Myung W.

    1999-01-01

    A hydrogen storage composition is provided which defines a physical sol-gel matrix having an average pore size of less than 3.5 angstroms which effectively excludes gaseous metal hydride poisons while permitting hydrogen gas to enter. The composition is useful for separating hydrogen gas from diverse gas streams which may have contaminants that would otherwise render the hydrogen absorbing material inactive.

  8. Development of a Tritium Cleanup System for a Large Helical Device Using Nonvolatile Getter Materials

    SciTech Connect

    Kawano, Takao; Sakuma, Yoichi; Kabutomori, Toshiki; Shibuya, Mamoru

    2000-01-15

    A tritium cleanup system has been conceptually developed for the large helical device (LHD) at the National Institute for Fusion Science. The system is a processing device employed to remove tritium from exhaust gas. In the exhaust gas discharged from the LHD in normal operation, the major part of tritium constituents should be in a form of hydrogen molecules because the fuel used in plasma experiments with the LHD is hydrogen molecules. From this viewpoint, we have designed a tritium cleanup system, which is characterized by tritium being removed and stored in a form of hydrogen molecules with less impurities, like oxygen and carbon, and its decomposition and the separation processes are introduced to convert various tritiated compounds into a form of hydrogen molecules of high purity. Besides these, there is another aspect in that getter materials are applied in both decomposition of tritiated compounds and storage of hydrogen molecules containing tritium.The system design is composed of three essential component parts: a hydrogen separator, a hydrogen absorbing vessel, and a decomposition process vessel. The hydrogen separator and the decomposition process vessel make a process loop repeat to remove hydrogen into a form of hydrogen molecules with less impurities. It is important that 'less impurities' means having a less bad influence on hydrogen-absorbing materials used in the storage vessel.We think that the hydrogen separator will be manufactured by employing a palladium hydrogen purifier system, which is available in the marketplace, and the hydrogen storage vessel will also be manufactured by using hydrogen-absorbing alloys like titanium. Thus, the serious problem imposed on us is how to realize the decomposition process vessel. To develop the decomposition process vessel, we thought nonvolatile getter materials were promising and carried out performance tests of methane decomposition by the nonvolatile getter materials, where methane was used because it is

  9. RENEWABLE LIQUID GETTERING PUMP

    DOEpatents

    Batzer, T.H.

    1962-08-21

    A method and structure were developed for pumping gases by simple absorption into a liquid gettering material. The invention comprises means ror continuously pumping a liquid getterrng material from a reservoir to the top of a generally vertical surface disposed in a vacuum pumping chamber to receive gaseous and other particles in the liquid gettering material which continuously flows downward over the vertical suiface. Means are provided for continuous removal, degassing, and return of a portion of the liquid gettering material from the reservoir connected with collectrng means at the base of the generally vertical plate. (AEC)

  10. Hydrogen gas relief valve

    DOEpatents

    Whittlesey, Curtis C.

    1985-01-01

    An improved battery stack design for an electrochemical system having at least one cell from which a gas is generated and an electrolyte in communication with the cell is described. The improved battery stack design features means for defining a substantially closed compartment for containing the battery cells and at least a portion of the electrolyte for the system, and means in association with the compartment means for selectively venting gas from the interior of the compartment means in response to the level of the electrolyte within the compartment means. The venting means includes a relief valve having a float member which is actuated in response to the level of the electrolyte within the compartment means. This float member is adapted to close the relief valve when the level of the electrolyte is above a predetermined level and open the relief valve when the level of electrolyte is below this predetermined level.

  11. Assuring ultra-clean environments in microsystem packages : irreversible and reversible getters.

    SciTech Connect

    Zifer, Thomas; Whinnery, LeRoy L., Jr.; Hollenshead, Jeromy Todd; Buffleben, George M.; McElhanon, James Ross; Nilson, Robert H.

    2003-11-01

    A new generation of irreversible, chemically reacting getters specifically targeted toward assuring the integrity of the local environment within microsystem packages were developed and evaluated. These reactive getters incorporate volatile species into a polymer through covalent bonds, thus producing a non-volatile product. These reactive getters will be combined with getters that rely on absorption media (e.g. zeolites and high surface area carbon fibers) to scavenge non-reactive species, like solvents. Our getter systems will rely on device packaging to limit exchange between the microsystem and the global environment. Thus, the internal getters need only provide local environmental control within the microsystem package. A series of experiments were conducted to determine uptake rates and capacities absorption and reactive-based getters. Diffusion rates through the binder used to hold the getter particles together were also investigated. Getters were evaluated in environments with a saturated headspace and with a limited amount of the volatile species of interest. One- and two-dimensional numerical models and analysis techniques have been developed and used to predict the transport of contaminant species within a representative microsystem package consisting of an open gas-filled volume adjacent to a polymer layer containing embedded particles of getter. The two-dimensional model features explicit representation of the individual getter particles while the one-dimensional treatment assumes a homogeneous distribution of getter material within the getterlpolymer layer. Example calculations illustrate the dependence of getter performance on reaction rates, polymer diffusivity, and getter particle volume fraction. In addition, the model is used to deduce surface reaction rates, solid phase diffusivities, and maximum-loading densities by least-squares fitting of model predictions to measured histories of gas-phase contaminant concentration and getter weight gain.

  12. Comparison of methods for separating small quantities of hydrogen isotopes from an inert gas

    SciTech Connect

    Willms, R.S.; Tuggle, D.; Birdsell, S.; Parkinson, J.; Price, B.; Lohmeir, D.

    1998-03-01

    It is frequent within tritium processing systems that a small amount of hydrogen isotopes (Q{sub 2}) must be separated from an inert gas such as He, Ar and N{sub 2}. Thus, a study of presently available technologies for effecting such a separation was performed. A base case and seven technology alternatives were identified and a simple design of each was prepared. These technologies included oxidation-adsorption-metal bed reduction, oxidation-adsorption-palladium membrane reactor, cryogenic adsorption, cryogenic trapping, cryogenic distillation, hollow fiber membranes, gettering and permeators. It was found that all but the last two methods were unattractive for recovering Q{sub 2} from N{sub 2}. Reasons for technology rejection included (1) the method unnecessarily turns the hydrogen isotopes into water, resulting in a cumbersome and more hazardous operation, (2) the method would not work without further processing, and (3) while the method would work, it would only do so in an impractical way. On the other hand, getters and permeators were found to be attractive methods for this application. Both of these methods would perform the separation in a straightforward, essentially zero-waste, single step operation. The only drawback for permeators was that limited low-partial Q{sub 2} pressure data is available. The drawbacks for getters are their susceptibility to irreversible and exothermic reaction with common species such as oxygen and water, and the lack of long-term operation of such beds. More research is envisioned for both of these methods to mature these attractive technologies.

  13. New Gas Polarographic Hydrogen Sensor

    NASA Technical Reports Server (NTRS)

    Dominguez, Jesus A.; Barile, Ron

    2004-01-01

    Polarography is the measurement of the current that flows in solution as a function of an applied voltage. The actual form of the observed polarographic current depends upon the manner in which the voltage is applied and on the characteristics of the working electrode. The new gas polarographic H2 sensor shows a current level increment with concentration of the gaseous H2 similar to those relating to metal ions in liquid electrolytes in well-known polarography. This phenomenon is caused by the fact that the diffusion of the gaseous H2 through a gas diffusion hole built in the sensor is a rate-determining step in the gaseous-hydrogen sensing mechanism. The diffusion hole artificially limits the diffusion of the gaseous H2 toward the electrode located at the sensor cavity. This gas polarographic H2 sensor. is actually an electrochemical-pumping cell since the gaseous H2 is in fact pumped via the electrochemical driving force generated between the electrodes. Gaseous H2 enters the diffusion hole and reaches the first electrode (anode) located in the sensor cavity to be transformed into an H+ ions or protons; H+ ions pass through the electrolyte and reach the second electrode (cathode) to be reformed to gaseous H2. Gas polarographic 02 sensors are commercially available; a gas polarographic 02 sensor was used to prove the feasibility of building a new gas polarographic H2 sensor.

  14. Device removes hydrogen gas from enclosed spaces

    NASA Technical Reports Server (NTRS)

    Carson, W. N.

    1966-01-01

    Hydrogen-oxidant galvanic cell removes small amounts of hydrogen gas continually released from equipment, such as vented silver-zinc batteries, in enclosed compartments where air venting is not feasible. These cells are used in satellite compartments.

  15. QED-1 device and measurements of gettering efficiency for a simulated divertor plasma

    SciTech Connect

    Owens, D.K.; Yamada, M.

    1980-03-01

    The QED-1 device at PPL has provided gettering efficiency data for neutralized hydrogen plasma on titanium. The hollow-anode arcjet produces a plasma column 1 cm in diameter with 10/sup 12/ < n/sub e/ < 10/sup 15/ cm/sup -3/ and T/sub i/ approx.< T/sub e/ = 3-10 eV, confined by an axial magnetic field of 1-6 kG. The gettering measurements are based on monitoring neutral gas density with respect to time in the divertor simulation chamber of QED-1. The present results indicate that the plasma particles lose their charge and most of their energy when they strike the neutralizer plate.

  16. Evaluation of H2 Getter Materials for Use in the TRUPACT-II

    SciTech Connect

    Livingston, R.R.

    1999-11-15

    Savannah River Site (SRS) has many waste drums containing Pu-238 that exceed the currently allowed wattage for transportation in the Transuranic Package Transporter-II (TRUPACT-II). By eliminating layers of confinement in waste drums and using getters to remove hydrogen gas, the TRUPACT-II waste loading can be increased significantly, with the potential of reaching the package''s 40-watt thermal limit. The cost savings associated with increasing the waste loading are enormous, and can be measured by reduced numbers of shipments, required processing facilities, and years of effort. To support the decision-making process and provide a good starting point for future development efforts at SRTC, the design requirements for a getter system to be used in the TRUPACT-II were compiled and are discussed in detail in the Appendix.

  17. Gettering and passivation of high efficiency multicrystalline silicon solar cells

    NASA Astrophysics Data System (ADS)

    Rohatgi, A.; Narasimha, S.; Cai, L.

    1997-02-01

    A detailed study was conducted on aluminum and phosphorus gettering in HEM mc-Si and defect passivation by PECVD SiN in EFG mc-Si to achieve high efficiency solar cells on these promising photovoltaic materials. Solar cells with efficiencies as high as 18.6% (1 cm2 area) were achieved on multicrystalline silicon (mc-Si) grown by the heat exchanger method (HEM) by a process which implements impurity gettering, an effective back surface field, front surface passivation, and forming gas annealing. This represents the highest reported solar cell efficiency on mc-Si to date. PCD analysis revealed that the bulk lifetime in certain HEM samples after phosphorus gettering can be as high as 135 μs. By incorporating a deeper aluminum back surface field (Al-BSF), the back surface recombination velocity (Sb) for 0.65 Ω-cm HEM mc-Si solar cells was lowered from 10,000 cm/s to 2,000 cm/s resulting in the 18.6% efficient device. It was also observed that a screen-printed/RTP alloyed Al-BSF process could raise the efficiency of both float zone and relatively defect-free mc-Si solar cells by lowering Sb. However, this process was found to increase the electrical activity of extended defects so that mc-Si devices with a significant defect density showed an overall degradation in performance. In the case of EFG mc-Si, neural network modeling in conjunction with a study of post deposition annealing was used to provide guidelines for effective defect passivation by PECVD SiN films. Appropriate deposition and annealing conditions resulted in a 45% increase in cell efficiency due to AR coating and another 25-30% increase due to defect passivation by atomic hydrogen.

  18. User’s Guide for Getter Rate Test System

    SciTech Connect

    Elmore, Monte R.

    2007-06-27

    This User’s Guide describes the operation and maintenance of the Getter Rate Test System, including the mechanical equipment, instrumentation, and datalogger/computer components. The Getter Rate Test System includes equipment and instrumentation to conduct two getter rate tests simultaneously. The mechanical equipment comprises roughing and high-vacuum pumps, heated test chambers, standard hydrogen leaks, and associated piping and valves. Instrumentation includes thermocouples, pressure (vacuum) transducers, panel displays, analog-to-digital signal converter, and associated wiring. The datalogger/computer is a stand-alone computer with installed software to allow the user to record data input from the pressure transducers to data files and to calculate the getter rate from the data in an Excel® spreadsheet.

  19. A new technique for pumping hydrogen gas

    USGS Publications Warehouse

    Friedman, I.; Hardcastle, K.

    1970-01-01

    A system for pumping hydrogen gas without isotopic fractionation has been developed. The pump contains uranium metal, which when heated to about 80??C reacts with hydrogen to form UH3. The UH3 is heated to above 500??C to decompose the hydride and regenerate the hydrogen. ?? 1970.

  20. Hydrogen gas sensor and method of manufacture

    DOEpatents

    McKee, John M.

    1991-01-01

    A sensor for measuring the pressure of hydrogen gas in a nuclear reactor, and method of manufacturing the same. The sensor comprises an elongated tube of hydrogen permeable material which is connected to a pressure transducer through a feedthrough tube which passes through a wall at the boundary of the region in which hydrogen is present. The tube is pressurized and flushed with hydrogen gas at an elevated temperature during the manufacture of the sensor in order to remove all gasses other than hydrogen from the device.

  1. Gettering Silicon Wafers with Phosphorus

    NASA Technical Reports Server (NTRS)

    Daiello, R. V.

    1983-01-01

    Silicon wafers subjected to gettering in phosphorus atmosphere have longer diffusion lengths and higher solar-cell efficiencies than untreated wafers. Gettering treatment improves properties of solar cells manufactured from impure silicon and is compatible with standard solar-cell processing.

  2. Taxis Toward Hydrogen Gas by Methanococcus maripaludis

    PubMed Central

    Brileya, Kristen A.; Connolly, James M.; Downey, Carey; Gerlach, Robin; Fields, Matthew W.

    2013-01-01

    Knowledge of taxis (directed swimming) in the Archaea is currently expanding through identification of novel receptors, effectors, and proteins involved in signal transduction to the flagellar motor. Although the ability for biological cells to sense and swim toward hydrogen gas has been hypothesized for many years, this capacity has yet to be observed and demonstrated. Here we show that the average swimming velocity increases in the direction of a source of hydrogen gas for the methanogen, Methanococcus maripaludis using a capillary assay with anoxic gas-phase control and time-lapse microscopy. The results indicate that a methanogen couples motility to hydrogen concentration sensing and is the first direct observation of hydrogenotaxis in any domain of life. Hydrogenotaxis represents a strategy that would impart a competitive advantage to motile microorganisms that compete for hydrogen gas and would impact the C, S and N cycles. PMID:24189441

  3. Integrated Mirco-Machined Hydrogen Gas Sensors

    SciTech Connect

    Frank DiMeoJr. Ing--shin Chen

    2005-12-15

    The widespread use of hydrogen as both an industrial process gas and an energy storage medium requires fast, selective detection of hydrogen gas. This report discusses the development of a new type of solid-state hydrogen gas sensor that couples novel metal hydride thin films with a MEMS (Micro-Electro-Mechanical System) structure known as a micro-hotplate. In this project, Micro-hotplate structures were overcoated with engineered multilayers that serve as the active hydrogen-sensing layer. The change in electrical resistance of these layers when exposed to hydrogen gas was the measured sensor output. This project focused on achieving the following objectives: (1) Demonstrating the capabilities of micro-machined H2 sensors; (2) Developing an understanding of their performance; (3) Critically evaluating the utility and viability of this technology for life safety and process monitoring applications. In order to efficiently achieve these objectives, the following four tasks were identified: (1) Sensor Design and Fabrication; (2) Short Term Response Testing; (3) Long Term Behavior Investigation; (4) Systems Development. Key findings in the project include: The demonstration of sub-second response times to hydrogen; measured sensitivity to hydrogen concentrations below 200 ppm; a dramatic improvement in the sensor fabrication process and increased understanding of the processing properties and performance relationships of the devices; the development of improved sensing multilayers; and the discovery of a novel strain based hydrogen detection mechanism. The results of this program suggest that this hydrogen sensor technology has exceptional potential to meet the stringent demands of life safety applications as hydrogen utilization and infrastructure becomes more prevalent.

  4. Materials for the scavenging of hydrogen at high temperatures

    DOEpatents

    Shepodd, T.J.; Phillip, B.L.

    1997-12-30

    A hydrogen getter composition is described comprising a double or triple bonded hydrocarbon with a high melting point useful for removing hydrogen gas, to partial pressures below 0.01 torr, from enclosed spaces and particularly from vessels used for transporting or containing fluids at elevated temperatures. The hydrogen getter compositions disclosed herein and their reaction products will neither melt nor char at temperatures in excess of 100 C. They possess significant advantages over conventional hydrogen getters, namely low risk of fire or explosion, no requirement for high temperature activation or operation, the ability to absorb hydrogen even in the presence of contaminants such as water, water vapor, common atmospheric gases and oil mists and are designed to be disposed within the confines of the apparatus. These getter materials can be mixed with binders, such as fluoropolymers, which permit the getter material to be fabricated into useful shapes and/or impart desirable properties such as water repellency or impermeability to various gases. 7 figs.

  5. Materials for the scavenging of hydrogen at high temperatures

    DOEpatents

    Shepodd, T.J.; Phillip, B.L.

    1997-04-29

    A hydrogen getter composition is described comprising a double or triple bonded hydrocarbon with a high melting point useful for removing hydrogen gas, to partial pressures below 0.01 torr, from enclosed spaces and particularly from vessels used for transporting or containing fluids at elevated temperatures. The hydrogen getter compositions disclosed herein and their reaction products will neither melt nor char at temperatures in excess of 100C. They possess significant advantages over conventional hydrogen getters, namely low risk of fire or explosion, no requirement for high temperature activation or operation, the ability to absorb hydrogen even in the presence of contaminants such as water, water vapor, common atmospheric gases and oil mists and are designed to be disposed within the confines of the apparatus. These getter materials can be mixed with binders, such as fluoropolymers, which permit the getter material to be fabricated into useful shapes and/or impart desirable properties such as water repellency or impermeability to various gases. 7 figs.

  6. Hydrogen-rich gas generator

    NASA Technical Reports Server (NTRS)

    Houseman, J.; Cerini, D. J. (Inventor)

    1976-01-01

    A process and apparatus are described for producing hydrogen-rich product gases. A spray of liquid hydrocarbon is mixed with a stream of air in a startup procedure and the mixture is ignited for partial oxidation. The stream of air is then heated by the resulting combustion to reach a temperature such that a signal is produced. The signal triggers a two way valve which directs liquid hydrocarbon from a spraying mechanism to a vaporizing mechanism with which a vaporized hydrocarbon is formed. The vaporized hydrocarbon is subsequently mixed with the heated air in the combustion chamber where partial oxidation takes place and hydrogen-rich product gases are produced.

  7. Regasification of liquefied natural gas and hydrogen

    NASA Astrophysics Data System (ADS)

    Tonkonog, V. G.; Tukmakov, A. L.; Muchitova, K. M.; Agalakov, U. A.; Serazetdinov, F. Sh; Gromov, B. C.

    2016-06-01

    Liquefied natural gas and hydrogen gasification process is suggested, in which vapor phase is generated by the decrease of internal energy of the liquid. Methane and hydrogen gasification processes have been numerically modeled. Flow rates of the methane and hydrogen through choke channel were defined. A satisfactory match between the modeled and experimental data for liquid nitrogen has been acquired. Technical suitability of the suggested process is proved. Based on the initial parameters of the cryogenic fluid, the amount of vapor phase is 5-20% of the flow rate.

  8. Titanium-nitrogen reaction investigated for application to gettering systems

    NASA Technical Reports Server (NTRS)

    Arntzen, J. D.; Coleman, L. F.; Kyle, M. L.; Pierce, R. D.

    1968-01-01

    Titanium is one of several gettering materials available for removing nitrogen from inert gases. The reaction rate of titanium-metal sponge and nitrogen in argon-nitrogen mixtures was studied at 900 degrees C. The rate was found to depend upon the partial pressure of nitrogen in the gas phase. Mathematical relationships simulate titanium systems.

  9. Irreversible gettering of thionyl chloride

    SciTech Connect

    LeRoy Whinnery; Steve Goods; George Buffleben; Tim Sheppodd

    1999-11-01

    The authors have successfully demonstrated the irreversible gettering of SOCl{sub 2} by ZnO/ASZMTEDA carbon over a modest temperature range. While thionyl chloride decomposition was slow below {minus}20 C, lower temperatures are expected to be less of a problem than at higher temperatures. The approximately 30 cc of thionyl chloride in a typical D-cell would require 50 g of ZnO and 107 g of ASZMTEDA carbon. Fortunately, since it is unlikely to happen at all, it is common practice to assume only one cell will fail (leak) in a given battery pack. So, one charge of getter can protect the whole battery pack. In summary, ZnO/ASZMTEDA carbon fulfills all of the requirements of an ideal getter including: irreversible binding or reaction with SOCl{sub 2}, high volumetric uptake capacity, high efficiency, non-volatile, air stable, insensitive to poisoning, non-toxic, cheap, non-corrosive, and the gettering product is not a liquid or oil that could block further flow or accessibility. Future work in this area includes incorporation of the ZnO and carbon into a structural open-celled porous monolith, as well as, gettering for other types of batteries (e.g., Li/MnO{sub 2}).

  10. Mechanochemistry of lithium nitride under hydrogen gas.

    PubMed

    Li, Z; Zhang, J; Wang, S; Jiang, L; Latroche, M; Du, J; Cuevas, F

    2015-09-14

    Hydrogen uptake during the mechanochemistry of lithium nitride under 9 MPa hydrogen pressure has been analyzed by means of in situ solid-gas absorption and ex situ X-ray diffraction (XRD) measurements. In situ hydrogenation curves show two H-sorption steps leading to an overall hydrogen uptake of 9.8 wt% H after 3 hours of milling. The milled end-products consist of nanocrystalline (∼10 nm) LiNH2 and LiH phases. The first reaction step comprises the transformation of the polymorph α-Li3N (S.G. P6/mmm) into the β-Li3N (S.G. P63/mmc) metastable phase and the reaction of the latter with hydrogen to form lithium imide: β-Li3N + H2→ Li2NH + LiH. Reaction kinetics of the first step is zero-order. Its rate-limiting control is assigned to the collision frequency between milling balls and Li3N powder. In the second absorption step, lithium imide converts to lithium amide following the reaction scheme Li2NH + H2→ LiNH2 + LiH. Reaction kinetics is here limited by one-dimensional nucleation and the growth mechanism, which, in light of structural data, is assigned to the occurrence of lithium vacancies in the imide compound. This study provides new insights into the reaction paths and chemical kinetics of light hydrogen storage materials during their mechanochemical synthesis.

  11. Automated Hydrogen Gas Leak Detection System

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Gencorp Aerojet Automated Hydrogen Gas Leak Detection System was developed through the cooperation of industry, academia, and the Government. Although the original purpose of the system was to detect leaks in the main engine of the space shuttle while on the launch pad, it also has significant commercial potential in applications for which there are no existing commercial systems. With high sensitivity, the system can detect hydrogen leaks at low concentrations in inert environments. The sensors are integrated with hardware and software to form a complete system. Several of these systems have already been purchased for use on the Ford Motor Company assembly line for natural gas vehicles. This system to detect trace hydrogen gas leaks from pressurized systems consists of a microprocessor-based control unit that operates a network of sensors. The sensors can be deployed around pipes, connectors, flanges, and tanks of pressurized systems where leaks may occur. The control unit monitors the sensors and provides the operator with a visual representation of the magnitude and locations of the leak as a function of time. The system can be customized to fit the user's needs; for example, it can monitor and display the condition of the flanges and fittings associated with the tank of a natural gas vehicle.

  12. GaN resistive hydrogen gas sensors

    NASA Astrophysics Data System (ADS)

    Yun, Feng; Chevtchenko, Serguei; Moon, Yong-Tae; Morkoç, Hadis; Fawcett, Timothy J.; Wolan, John T.

    2005-08-01

    GaN epilayers grown by organometallic vapor phase epitaxy have been used to fabricate resistive gas sensors with a pair of planar ohmic contacts. Detectible sensitivity to H2 gas for a wide range of gas mixtures in an Ar ambient has been realized; the lowest concentration tested is ˜0.1% H2 (in Ar), well below the lower combustion limit in air. No saturation of the signal is observed up to 100% H2 flow. Real-time response to H2 shows a clear and sharp response with no memory effects during the ramping cycles of H2 concentration. The change in current at a fixed voltage to hydrogen was found to change with sensor geometry. This appears to be consistent with a surface-adsorption-induced change of conductivity; a detailed picture of the gas sensing mechanism requires further systematic studies.

  13. Efficient combining of ion pumps and getter-palladium thin films

    SciTech Connect

    Paolini, C.; Mura, M.; Ravelli, F.

    2008-07-15

    Nonevaporable getters (NEGs) have been extensively studied in the last several years for their sorption properties toward many gases. In particular, an innovative alloy as a thin film by magnetron sputtering was developed and characterized at the European Organization for Nuclear Research. It is composed of Ti-Zr-V and protected by an overlayer of palladium (Pd), according to a technology for which the authors got the licence. NEG-Pd thin films used in combination with ion getter pumps is a simple, easy way to handle pumping devices for ultrahigh and extremely high vacuum applications. To show how to apply this coating technology to the internal surface of different types of ion pumps, the authors carried out several tests on pumps of various shapes, sizes (in terms of nominal pumping speed), and types (diode, noble diode, and triode). Special care was taken during the thermal cycle of baking and activation of the pumps to preserve the internal film from sources of contamination and/or from the sputtering of the titanium cathodes of the pump. Some important remarks will be made about the most appropriate conditions of pressure and temperature. The performance of the NEG-Pd-coated ion pumps was evaluated in terms of ultimate pressure and hydrogen pumping speed. The contribution of the thin film is particularly relevant for the pumping of this gas, due to its high sticking factor on palladium and the great sorption capacity of the underlying getter. Finally, the possibility of further improvement by substituting palladium with other Pd-based alloys will also be evaluated.

  14. SAES St 909 Getter Testing at the Savannah River National Laboratory

    SciTech Connect

    Klein, J. E.; Holder, J. E

    2005-09-07

    Process gas tritium stripper technology has gone from catalytic oxidation followed by absorption on molecular sieve/zeolite beds to non-evaporate metal getter technology. SAES Getters produces a number of commercial getter products including St 909. St 909, a Zr-Mn-Fe alloy, is sold in pellet form, can decompose (''crack'') a number of process gas impurities, and retains lower levels of tritium than other getters. The performance of this material to remove process impurities, especially methane, under of variety of operating conditions has been part of a Savannah River National Laboratory (SRNL) for five years. St 909 has been tested at the bench (6 gram) scale, the pilot (500 gram) scale, and at the full (5300) gram scale under a variety of test conditions. This paper gives a brief summary of test results obtained for the different scale tests.

  15. Hydrogen gas storage in fluorinated ultramicroporous tunnel crystal.

    PubMed

    Kataoka, Keisuke; Katagiri, Toshimasa

    2012-08-21

    We report hydrogen storage at an ordinary pressure due to a bottle-neck effect of an ultramicroporous crystal. Stored hydrogen was kept at an ordinary pressure below -110 °C. The amounts of stored hydrogen gas linearly correlated with the initial pressures. These phenomena suggested the ultramicroporous tunnels worked as a molecular gas cylinder. PMID:22782245

  16. Precipitated iron: A limit on gettering efficacy in multicrystalline silicon

    NASA Astrophysics Data System (ADS)

    Fenning, D. P.; Hofstetter, J.; Bertoni, M. I.; Coletti, G.; Lai, B.; del Cañizo, C.; Buonassisi, T.

    2013-01-01

    A phosphorus diffusion gettering model is used to examine the efficacy of a standard gettering process on interstitial and precipitated iron in multicrystalline silicon. The model predicts a large concentration of precipitated iron remaining after standard gettering for most as-grown iron distributions. Although changes in the precipitated iron distribution are predicted to be small, the simulated post-processing interstitial iron concentration is predicted to depend strongly on the as-grown distribution of precipitates, indicating that precipitates must be considered as internal sources of contamination during processing. To inform and validate the model, the iron distributions before and after a standard phosphorus diffusion step are studied in samples from the bottom, middle, and top of an intentionally Fe-contaminated laboratory ingot. A census of iron-silicide precipitates taken by synchrotron-based X-ray fluorescence microscopy confirms the presence of a high density of iron-silicide precipitates both before and after phosphorus diffusion. A comparable precipitated iron distribution was measured in a sister wafer after hydrogenation during a firing step. The similar distributions of precipitated iron seen after each step in the solar cell process confirm that the effect of standard gettering on precipitated iron is strongly limited as predicted by simulation. Good agreement between the experimental and simulated data supports the hypothesis that gettering kinetics is governed by not only the total iron concentration but also by the distribution of precipitated iron. Finally, future directions based on the modeling are suggested for the improvement of effective minority carrier lifetime in multicrystalline silicon solar cells.

  17. Advanced IGCC/Hydrogen Gas Turbine Development

    SciTech Connect

    York, William; Hughes, Michael; Berry, Jonathan; Russell, Tamara; Lau, Y. C.; Liu, Shan; Arnett, Michael; Peck, Arthur; Tralshawala, Nilesh; Weber, Joseph; Benjamin, Marc; Iduate, Michelle; Kittleson, Jacob; Garcia-Crespo, Andres; Delvaux, John; Casanova, Fernando; Lacy, Ben; Brzek, Brian; Wolfe, Chris; Palafox, Pepe; Ding, Ben; Badding, Bruce; McDuffie, Dwayne; Zemsky, Christine

    2015-07-30

    The objective of this program was to develop the technologies required for a fuel flexible (coal derived hydrogen or syngas) gas turbine for IGCC that met DOE turbine performance goals. The overall DOE Advanced Power System goal was to conduct the research and development (R&D) necessary to produce coal-based IGCC power systems with high efficiency, near-zero emissions, and competitive capital cost. To meet this goal, the DOE Fossil Energy Turbine Program had as an interim objective of 2 to 3 percentage points improvement in combined cycle (CC) efficiency. The final goal is 3 to 5 percentage points improvement in CC efficiency above the state of the art for CC turbines in IGCC applications at the time the program started. The efficiency goals were for NOx emissions of less than 2 ppm NOx (@15 % O2). As a result of the technologies developed under this program, the DOE goals were exceeded with a projected 8 point efficiency improvement. In addition, a new combustion technology was conceived of and developed to overcome the challenges of burning hydrogen and achieving the DOE’s NOx goal. This report also covers the developments under the ARRA-funded portion of the program that include gas turbine technology advancements for improvement in the efficiency, emissions, and cost performance of gas turbines for industrial applications with carbon capture and sequestration. Example applications could be cement plants, chemical plants, refineries, steel and aluminum plants, manufacturing facilities, etc. The DOE’s goal for more than 5 percentage point improvement in efficiency was met with cycle analyses performed for representative IGCC Steel Mill and IGCC Refinery applications. Technologies were developed in this program under the following areas: combustion, larger latter stage buckets, CMC and EBC, advanced materials and coatings, advanced configurations to reduce cooling, sealing and rotor purge flows, turbine aerodynamics, advanced sensors, advancements in first

  18. Compact solid source of hydrogen gas

    DOEpatents

    Kravitz, Stanley H.; Hecht, Andrew M.; Sylwester, Alan P.; Bell, Nelson S.

    2004-06-08

    A compact solid source of hydrogen gas, where the gas is generated by contacting water with micro-disperse particles of sodium borohydride in the presence of a catalyst, such as cobalt or ruthenium. The micro-disperse particles can have a substantially uniform diameter of 1-10 microns, and preferably about 3-5 microns. Ruthenium or cobalt catalytic nanoparticles can be incorporated in the micro-disperse particles of sodium borohydride, which allows a rapid and complete reaction to occur without the problems associated with caking and scaling of the surface by the reactant product sodium metaborate. A closed loop water management system can be used to recycle wastewater from a PEM fuel cell to supply water for reacting with the micro-disperse particles of sodium borohydride in a compact hydrogen gas generator. Capillary forces can wick water from a water reservoir into a packed bed of micro-disperse fuel particles, eliminating the need for using an active pump.

  19. Aluminum gettering in single and multicrystalline silicon

    SciTech Connect

    McHugo, S.A.; Hieslmair, H.; Weber, E.R.

    1995-08-01

    Al gettering has been performed on integrated circuit (I.C.) quality silicon and a variety of single and multicrystalline silicon solar cell materials. The minority carrier diffusion length, Ln, has been used to quantify the gettering response. Vast differences in response to the Al gettering treatment are observed between the I.C. quality silicon and the solar cell materials. The I.C. silicon generally responds well while the solar cell silicon performance progressively degrades with increasing gettering temperature. Preliminary data shows that by performing a Rapid Thermal Annealing treatment prior to the Al gettering, an improved or further degraded Ln emerges in solar cell material depending on the material`s manufacturer. We explain these observed phenomena by suggesting that Al gettering in solar cell silicon is an impurity emission-limited process while for I.C. quality silicon it is diffusion limited.

  20. Hydrogen-Enhanced Natural Gas Vehicle Program

    SciTech Connect

    Hyde, Dan; Collier, Kirk

    2009-01-22

    The project objective is to demonstrate the viability of HCNG fuel (30 to 50% hydrogen by volume and the remainder natural gas) to reduce emissions from light-duty on-road vehicles with no loss in performance or efficiency. The City of Las Vegas has an interest in alternative fuels and already has an existing hydrogen refueling station. Collier Technologies Inc (CT) supplied the latest design retrofit kits capable of converting nine compressed natural gas (CNG) fueled, light-duty vehicles powered by the Ford 5.4L Triton engine. CT installed the kits on the first two vehicles in Las Vegas, trained personnel at the City of Las Vegas (the City) to perform the additional seven retrofits, and developed materials for allowing other entities to perform these retrofits as well. These vehicles were used in normal service by the City while driver impressions, reliability, fuel efficiency and emissions were documented for a minimum of one year after conversion. This project has shown the efficacy of operating vehicles originally designed to operate on compressed natural gas with HCNG fuel incorporating large quantities of exhaust gas recirculation (EGR). There were no safety issues experienced with these vehicles. The only maintenance issue in the project was some rough idling due to problems with the EGR valve and piping parts. Once the rough idling was corrected no further maintenance issues with these vehicles were experienced. Fuel economy data showed no significant changes after conversion even with the added power provided by the superchargers that were part of the conversions. Driver feedback for the conversions was very favorable. The additional power provided by the HCNG vehicles was greatly appreciated, especially in traffic. The drivability of the HCNG vehicles was considered to be superior by the drivers. Most of the converted vehicles showed zero oxides of nitrogen throughout the life of the project using the State of Nevada emissions station.

  1. In situ pressure measurements in small gettered volumes

    NASA Astrophysics Data System (ADS)

    Nemanic, Vincenc; Zumer, Marko; Zajec, Bojan

    2002-11-01

    In modern small optoelectronic devices like field emitter displays, miniature cathode ray tubes (CRTs), channel photomultipliers, etc., the vacuum requirements are much more stringent than in conventional electron beam devices. As there should be a pressure in the ultrahigh vacuum region and the volume is only a few cm3, a direct measurement is not feasible and is often estimated on the basis of the expected pumping speed of the getter. The present study was arranged to investigate the pressure in small CRTs (25 cm3) during a period of several months, namely after the conventional pumping and bakeout procedure, immediately after the activation of Ba getters and after the accumulation of some months. All the CRTs were equipped by a spinning rotor gauge ball. Two barium getter sizes were studied: St15/AM/O/9.5 and St15/AM/O/5, both made by SAES. After the evaporation by the prescribed procedure the pressure did not drop, but increased from papprox1 x10-5 mbar up to papprox1 x10-3 mbar, showing that the pumping speed was completely suppressed by forming of a nongetterable gas. When the same experiments were repeated inside identical glass bulbs connected with a valve to a quadrupole mass spectrometer, a formation of methane was observed. The initial rate just after the activation was Qapprox10-8 mbar l s-1, but even after several hours it was still as high as Qapprox10-9 mbar l s-1. By switching-on the cathode heater, methane was pumped by the getter after a precedent cracking procedure. The virtual pumping speed was directly related to the heater power, but independent of the getter area. Therefore, within the cathode warm-up period, methane was "pumped" and did not represent a harmful gaseous contaminant in a small electron beam device with a thermionic cathode. copyright 2002 American Vacuum Society.

  2. Titanium-Based Getter Solution for Wafer-Level MEMS Vacuum Packaging

    NASA Astrophysics Data System (ADS)

    Chidambaram, Vivek; Ling, Xie; Bangtao, Chen

    2013-03-01

    Ultrahigh-vacuum conditions can be achieved by employing porous absorbent materials such as Ti, Zr, Ta, and Yt. Commercial getters are primarily Zr-based, since Zr possesses the best adsorption characteristics. Titanium is not considered as a candidate, since adsorption of gases by Ti is significantly reduced due to oxidation and other contamination. In the present work, it is demonstrated that the adsorption property of Ti can be substantially enhanced and benchmarked against other Zr-based commercial getters by employing a sacrificial layer such as Ni over Ti, and also by using other surface engineering techniques. It has been confirmed that, in addition to the activation temperature, the vacuum level during getter activation also plays a pivotal role in influencing the adsorption characteristics of Ti. It has been determined that the getter life could be significantly improved by the reversible adsorption characteristic of H2 gas, facilitating regeneration cycles.

  3. Gas distribution equipment in hydrogen service - Phase II

    NASA Technical Reports Server (NTRS)

    Jasionowski, W. J.; Huang, H. D.

    1980-01-01

    The hydrogen permeability of three different types of commercially available natural gas polyethylene pipes was determined. Ring tensile tests were conducted on permeability-exposed and as-received samples. Hydrogen-methane leakage experiments were also performed. The results show no selective leakage of hydrogen via Poiseuille, turbulent, or orifice flow (through leaks) on the distribution of blends of hydrogen and methane. The data collected show that the polyethylene pipe is 4 to 6 times more permeable to hydrogen than to methane.

  4. Savannah River Site/K Area Complex getter life extension report.

    SciTech Connect

    Shepodd, Timothy J.; Woodsmall, Todd; Nissen, April

    2008-08-01

    The K Area Complex (KAC) at the Savannah River Site (SRS) has been utilizing HiTop hydrogen getter material in 9975 Shipping Containers to prevent the development of flammable environments during storage of moisture-containing plutonium oxides. Previous testing and subsequent reports have been performed and produced by Sandia National Laboratories (SNL) to demonstrate the suitability and longevity of the getter during storage at bounding thermal conditions. To date, results have shown that after 18 months of continuous storage at 70 C, the getter is able to both recombine gaseous hydrogen and oxygen into water when oxygen is available, and irreversibly getter (i.e. scavenge) hydrogen from the vapor space when oxygen is not available, both under a CO{sub 2} environment. [Refs. 1-5] Both of these reactions are catalytically enhanced and thermodynamically favorable. The purpose of this paper is to establish the justification that maintaining the current efforts of biannual testing is no longer necessary due to the robust performance of the getter material, the very unlikely potential that the recombination reaction will fail during storage conditions in KAC, and the insignificant aging effects that have been seen in the testing to date.

  5. Getter pumping speed measurements in the range 10/sup -2/ to 10/sup -7/ liters per second

    SciTech Connect

    Mehrhoff, T.K.; Barnes, L.W.

    1982-04-25

    A procedure for measurement of pumping speeds several orders of magnitude below the lowest reported rates is described. The method has been found to be useful in evaluating ambient hydrogen pumping characteristics for small getters in the presence of trace contaminant gases (less than 0.13 micromoles). Poisoning effects are described for the action of carbon monoxide and carbon dioxide on a zirconium-titanium nickel alloy bulk getter. Results obtained indicate the poisoning effect is much less severe in the case of barium flash getters.

  6. Technetium Getters to Improve Cast Stone Performance

    SciTech Connect

    Neeway, James J.; Lawter, Amanda R.; Serne, R. Jeffrey; Asmussen, Robert M.; Qafoku, Nikolla

    2015-10-15

    The cementitious material known as Cast Stone has been selected as the preferred waste form for solidification of aqueous secondary liquid effluents from the Hanford Tank Waste Treatment and Immobilization Plant (WTP) process condensates and low-activity waste (LAW) melter off-gas caustic scrubber effluents. Cast Stone is also being evaluated as a supplemental immobilization technology to provide the necessary LAW treatment capacity to complete the Hanford tank waste cleanup mission in a timely and cost effective manner. Two radionuclides of particular concern in these waste streams are technetium-99 (99Tc) and iodine-129 (129I). These radioactive tank waste components contribute the most to the environmental impacts associated with the cleanup of the Hanford site. A recent environmental assessment of Cast Stone performance, which assumes a diffusion controlled release of contaminants from the waste form, calculates groundwater in excess of the allowable maximum permissible concentrations for both contaminants. There is, therefore, a need and an opportunity to improve the retention of both 99Tc and 129I in Cast Stone. One method to improve the performance of Cast Stone is through the addition of “getters” that selectively sequester Tc and I, therefore reducing their diffusion out of Cast Stone. In this paper, we present results of Tc and I removal from solution with various getters with batch sorption experiments conducted in deionized water (DIW) and a highly caustic 7.8 M Na Ave LAW simulant. In general, the data show that the selected getters are effective in DIW but their performance is comprised when experiments are performed with the 7.8 M Na Ave LAW simulant. Reasons for the mitigated performance in the LAW simulant may be due to competition with Cr present in the 7.8 M Na Ave LAW simulant and to a pH effect.

  7. Hydrogen gas storage in fluorinated ultramicroporous tunnel crystal

    NASA Astrophysics Data System (ADS)

    Kataoka, Keisuke; Katagiri, Toshimasa

    2012-07-01

    We report hydrogen storage at an ordinary pressure due to a bottle-neck effect of an ultramicroporous crystal. Stored hydrogen was kept at an ordinary pressure below -110 °C. The amounts of stored hydrogen gas linearly correlated with the initial pressures. These phenomena suggested the ultramicroporous tunnels worked as a molecular gas cylinder.We report hydrogen storage at an ordinary pressure due to a bottle-neck effect of an ultramicroporous crystal. Stored hydrogen was kept at an ordinary pressure below -110 °C. The amounts of stored hydrogen gas linearly correlated with the initial pressures. These phenomena suggested the ultramicroporous tunnels worked as a molecular gas cylinder. Electronic supplementary information (ESI) available. CCDC 246922. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c2nr30940h

  8. Two-stage coal liquefaction without gas-phase hydrogen

    DOEpatents

    Stephens, H.P.

    1986-06-05

    A process is provided for the production of a hydrogen-donor solvent useful in the liquefaction of coal, wherein the water-gas shift reaction is used to produce hydrogen while simultaneously hydrogenating a donor solvent. A process for the liquefaction of coal using said solvent is also provided. The process enables avoiding the use of a separate water-gas shift reactor as well as high pressure equipment for liquefaction. 3 tabs.

  9. Ion-stimulated gas desorption yields of electropolished, chemically etched, and coated (Au, Ag, Pd, TiZrV) stainless steel vacuum chambers and St707 getter strips irradiated with 4.2 MeV/u lead ions

    NASA Astrophysics Data System (ADS)

    Mahner, E.; Hansen, J.; Küchler, D.; Malabaila, M.; Taborelli, M.

    2005-05-01

    The ion-induced desorption experiment, installed in the CERN Heavy-Ion Accelerator LINAC 3, has been used to measure molecular desorption yields for 4.2 MeV/u lead ions impacting under grazing incidence on different accelerator-type vacuum chambers. Desorption yields for H2, CH4, CO, and CO2, which are of fundamental interest for future accelerator applications, are reported for different stainless steel surface treatments. In order to study the effect of the surface oxide layer on the gas desorption, gold-, silver-, palladium-, and getter-coated 316 LN stainless steel chambers and similarly prepared samples were tested for desorption at LINAC 3 and analyzed for chemical composition by x-ray photoemission spectroscopy. The large effective desorption yield of 2×104 molecules /Pb53+ ion, previously measured for uncoated, vacuum fired stainless steel, was reduced after noble-metal coating by up to 2 orders of magnitude. In addition, pressure rise measurements, the effectiveness of beam scrubbing with lead ions, and the consequence of a subsequent venting on the desorption yields of a beam-scrubbed vacuum chamber are described. Practical consequences for the vacuum system of the future Low Energy Ion Ring are discussed.

  10. Fluorine gettering by activated charcoal in a radiation environment

    SciTech Connect

    Felker, L.K.; Toth, L.M.

    1988-10-01

    Activated charcoal has been shown to be an effective gettering agent for the fluorine gas that is liberated in a radiation environment. Even though activated charcoal is a commonly used getter, little is known about the radiation stability of the fluorine-charcoal product. This work has shown that not only is the product stable in high gamma radiation fields, but also that radiation enhances the capacity of the charcoal for the fluorine. The most useful application of this work is with the Molten Salt Reactor Experiment (MSRE) fuel salt because the radioactive components (fission products and actinides) cause radiolytic damage to the solid LiF-BeF/sub 2/-ZrF/sub 4/-UF/sub 4/ (64.5, 30.3, 5.0, 0.13 mol %, respectively) resulting in the liberation of fluorine gas. This work has also demonstrated that the maximum damage to the fuel salt by approx.3 /times/ 10/sup 7/ R/h gamma radiation is approximately 2%, at which point the rate of recombination of fluorine with active metal sites within the salt lattice equals the rate of fluorine generation. The enhanced reactivity of the activated charcoal and radiation stability of the product ensures that the gettered fluorine will stay sequestered in the charcoal.

  11. Evaluation of hydrogen as a cryogenic wind tunnel test gas

    NASA Technical Reports Server (NTRS)

    Haut, R. C.

    1977-01-01

    The nondimensional ratios used to describe various flow situations in hydrogen were determined and compared with the corresponding ideal diatomic gas ratios. The results were used to examine different inviscid flow configurations. The relatively high value of the characteristic rotational temperature causes the behavior of hydrogen, under cryogenic conditions, to deviate substantially from the behavior of an ideal diatomic gas in the compressible flow regime. Therefore, if an idea diatomic gas is to be modeled, cryogenic hydrogen is unacceptable as a wind tunnel test gas in a compressible flow situation.

  12. Hydrogen Gas Production from Nuclear Power Plant in Relation to Hydrogen Fuel Cell Technologies Nowadays

    SciTech Connect

    Yusibani, Elin; Kamil, Insan; Suud, Zaki

    2010-06-22

    Recently, world has been confused by issues of energy resourcing, including fossil fuel use, global warming, and sustainable energy generation. Hydrogen may become the choice for future fuel of combustion engine. Hydrogen is an environmentally clean source of energy to end-users, particularly in transportation applications because without release of pollutants at the point of end use. Hydrogen may be produced from water using the process of electrolysis. One of the GEN-IV reactors nuclear projects (HTGRs, HTR, VHTR) is also can produce hydrogen from the process. In the present study, hydrogen gas production from nuclear power plant is reviewed in relation to commercialization of hydrogen fuel cell technologies nowadays.

  13. Hydrogen Gas Production from Nuclear Power Plant in Relation to Hydrogen Fuel Cell Technologies Nowadays

    NASA Astrophysics Data System (ADS)

    Yusibani, Elin; Kamil, Insan; Suud, Zaki

    2010-06-01

    Recently, world has been confused by issues of energy resourcing, including fossil fuel use, global warming, and sustainable energy generation. Hydrogen may become the choice for future fuel of combustion engine. Hydrogen is an environmentally clean source of energy to end-users, particularly in transportation applications because without release of pollutants at the point of end use. Hydrogen may be produced from water using the process of electrolysis. One of the GEN-IV reactors nuclear projects (HTGRs, HTR, VHTR) is also can produce hydrogen from the process. In the present study, hydrogen gas production from nuclear power plant is reviewed in relation to commercialization of hydrogen fuel cell technologies nowadays.

  14. On-Board Hydrogen Gas Production System For Stirling Engines

    DOEpatents

    Johansson, Lennart N.

    2004-06-29

    A hydrogen production system for use in connection with Stirling engines. The production system generates hydrogen working gas and periodically supplies it to the Stirling engine as its working fluid in instances where loss of such working fluid occurs through usage through operation of the associated Stirling engine. The hydrogen gas may be generated by various techniques including electrolysis and stored by various means including the use of a metal hydride absorbing material. By controlling the temperature of the absorbing material, the stored hydrogen gas may be provided to the Stirling engine as needed. A hydrogen production system for use in connection with Stirling engines. The production system generates hydrogen working gas and periodically supplies it to the Stirling engine as its working fluid in instances where loss of such working fluid occurs through usage through operation of the associated Stirling engine. The hydrogen gas may be generated by various techniques including electrolysis and stored by various means including the use of a metal hydride absorbing material. By controlling the temperature of the absorbing material, the stored hydrogen gas may be provided to the Stirling engine as needed.

  15. Development Of A Centrifugal Hydrogen Pipeline Gas Compressor

    SciTech Connect

    Di Bella, Francis A.

    2015-04-16

    Concepts NREC (CN) has completed a Department of Energy (DOE) sponsored project to analyze, design, and fabricate a pipeline capacity hydrogen compressor. The pipeline compressor is a critical component in the DOE strategy to provide sufficient quantities of hydrogen to support the expected shift in transportation fuels from liquid and natural gas to hydrogen. The hydrogen would be generated by renewable energy (solar, wind, and perhaps even tidal or ocean), and would be electrolyzed from water. The hydrogen would then be transported to the population centers in the U.S., where fuel-cell vehicles are expected to become popular and necessary to relieve dependency on fossil fuels. The specifications for the required pipeline hydrogen compressor indicates a need for a small package that is efficient, less costly, and more reliable than what is available in the form of a multi-cylinder, reciprocating (positive displacement) compressor for compressing hydrogen in the gas industry.

  16. Self regulating formulations for safe hydrogen gettering

    DOEpatents

    Shepodd, Timothy Jon

    2002-01-01

    A method and composition are disclosed for preventing uncontrolled exothermic reaction in the presence of a catalyst. A catalyst deployed as a finely divided powder which is attached to the surface of a low melting point wax or wax-like material which is utilized as a carrier for the catalyst. During operation should the catalyst overheat due to uncontrolled conditions brought about by a run-away reaction the heat of reaction melts the low melting point wax which would itself wet the surface of the catalyst and prevent further catalysis.

  17. Self regulating formulations for safe hydrogen gettering

    DOEpatents

    Shepodd, Timothy Jon

    2004-03-16

    A method and composition are disclosed for preventing uncontrolled exothermic reaction in the presence of a catalyst. A catalyst deployed as a finely divided powder which is attached to the surface of a low melting point wax or wax-like material which is utilized as a carrier for the catalyst. During operation should the catalyst overheat due to uncontrolled conditions brought about by a run-away reaction the heat of reaction melts the low melting point wax which would itself wet the surface of the catalyst and prevent further catalysis.

  18. Adsorption process to recover hydrogen from feed gas mixtures having low hydrogen concentration

    DOEpatents

    Golden, Timothy Christopher; Weist, Jr., Edward Landis; Hufton, Jeffrey Raymond; Novosat, Paul Anthony

    2010-04-13

    A process for selectively separating hydrogen from at least one more strongly adsorbable component in a plurality of adsorption beds to produce a hydrogen-rich product gas from a low hydrogen concentration feed with a high recovery rate. Each of the plurality of adsorption beds subjected to a repetitive cycle. The process comprises an adsorption step for producing the hydrogen-rich product from a feed gas mixture comprising 5% to 50% hydrogen, at least two pressure equalization by void space gas withdrawal steps, a provide purge step resulting in a first pressure decrease, a blowdown step resulting in a second pressure decrease, a purge step, at least two pressure equalization by void space gas introduction steps, and a repressurization step. The second pressure decrease is at least 2 times greater than the first pressure decrease.

  19. Gaseous fueled vehicles: A role for natural gas and hydrogen

    SciTech Connect

    Blazek, C.F.; Jasionowski, W.J.

    1991-01-01

    The commercialization of gaseous hydrogen fueled vehicles requires both the development of hydrogen fueled vehicles and the establishment of a hydrogen fueling infrastructure. These requirements create a classic chicken and egg scenario in that manufacturers will not build and consumers will not buy vehicles without an adequate refueling infrastructure and potential refueling station operators will not invest the needed capital without an adequate market to serve. One solution to this dilemma is to create a bridging strategy whereby hydrogen is introduced gradually via another carrier. The only contending alternative fuel that can act as a bridge to hydrogen fueled vehicles is natural gas. To explore this possibility, IGT is conducting emission tests on its dedicated natural gas vehicle (NGV) test platform to determine what, if any, effects small quantities of hydrogen have on emissions and performance. Furthermore, IGT is actively developing an adsorbent based low-pressure natural gas storage system for NGV applications. This system has also shown promise as a storage media for hydrogen. A discussion of our research results in this area will be presented. Finally, a review of IGT's testing facility will be presented to indicate our capabilities in conducted natural gas/hydrogen vehicle (NGHV) research. 3 refs., 10 figs.

  20. Gettering of metal impurities in silicon

    SciTech Connect

    Schroeter, W.; Spiecker, E.; Apel, M.

    1995-08-01

    Gettering means the removal of metallic impurities from the device-active area of the wafer by transport to a predesigned region-called gettering layer (GL). We introduce an interface at z = d{sub GL}, at which the effect of the gettering mechanism on the metal impurity distribution in the wafer is quantified, e.g. by specifying currents or by interfacial reactions of metal impurities, self interstitials etc. between GL and wafer. In response metal impurities will diffuse out of the wafer into the gettering layer. Following such a concept, in general three species of the metal impurity (M) are involved in gettering: M{sub p} {l_arrow} M{sub i} {l_arrow} M{sub GL}. M{sub p} denotes immobile species in the wafer, which are precipitated into suicides or segregated at extended defects or whose diffusivity is too small to contribute noticeably to transport during the gettering procedure - like many substitutional metal species.

  1. Para-Hydrogen-Enhanced Gas-Phase Magnetic Resonance Imaging

    SciTech Connect

    Bouchard, Louis-S.; Kovtunov, Kirill V.; Burt, Scott R.; Anwar,M. Sabieh; Koptyug, Igor V.; Sagdeev, Renad Z.; Pines, Alexander

    2007-02-23

    Herein, we demonstrate magnetic resonance imaging (MRI) inthe gas phase using para-hydrogen (p-H2)-induced polarization. A reactantmixture of H2 enriched in the paraspin state and propylene gas is flowedthrough a reactor cell containing a heterogenized catalyst, Wilkinson'scatalyst immobilized on modified silica gel. The hydrogenation product,propane gas, is transferred to the NMR magnet and is spin-polarized as aresult of the ALTADENA (adiabatic longitudinal transport and dissociationengenders net alignment) effect. A polarization enhancement factor of 300relative to thermally polarized gas was observed in 1D1H NMR spectra.Enhancement was also evident in the magnetic resonance images. This isthe first demonstration of imaging a hyperpolarized gaseous productformed in a hydrogenation reaction catalyzed by a supported catalyst.This result may lead to several important applications, includingflow-through porous materials, gas-phase reaction kinetics and adsorptionstudies, and MRI in low fields, all using catalyst-free polarizedfluids.

  2. Process for hydrogen isotope concentration between liquid water and hydrogen gas

    DOEpatents

    Stevens, William H.

    1976-09-21

    A process for hydrogen isotope exchange and concentration between liquid water and hydrogen gas, wherein liquid water and hydrogen gas are contacted, in an exchange section, with one another and with at least one catalyst body comprising at least one metal selected from Group VIII of the Periodic Table and preferably a support therefor, the catalyst body has a liquid-water-repellent, gas permeable polymer or organic resin coating, preferably a fluorinated olefin polymer or silicone coating, so that the isotope concentration takes place by two simultaneously occurring steps, namely, ##EQU1## WHILE THE HYDROGEN GAS FED TO THE EXCHANGE SECTION IS DERIVED IN A REACTOR VESSEL FROM LIQUID WATER THAT HAS PASSED THROUGH THE EXCHANGE SECTION.

  3. Hydrogen mitigation Gas Characterization System: System design description

    SciTech Connect

    Schneider, T.C.

    1998-07-17

    The Gas Characterization System (GCS) design is described for flammable gas monitoring. Tank 241-SY-101 (SY-101) is known to experience periodic tank level increases and decreases during which hydrogen gas is released. It is believed that the generated gases accumulate in the solids-containing layer near the bottom of the tank. Solids and gases are also present in the crust and may be present in the interstitial liquid layer. The accumulation of gases creates a buoyancy that eventually overcomes the density and bonding strength of the bottom layer. When this happens, the gas from the bottom layer is released upward through the liquid layer to the vapor space above the tank crust. Previous monitoring of the vapor space gases during such an event indicates hydrogen release concentrations greater than the lower flammability limit (LFL) of hydrogen in a partial nitrous oxide atmosphere. Tanks 241-AN-105, 241-AW-101, and 241-SY-103 have been identified as having the potential to behave similar to SY-101. These waste tanks have been placed on the flammable gas watch list (FGWL). All waste tanks on the FGWL will have a standard hydrogen monitoring system (SHMS) installed to measure hydrogen. In the event that hydrogen levels exceed 0.75% by volume, additional characterization will be required. The purpose of this additional vapor space characterization is to determine the actual lower flammability limit of these tanks, accurately measure low baseline gas release concentrations, and to determine potential hazards associated with larger Gas Release Events (GREs). The instruments to be installed in the GCS for vapor monitoring will allow accurate analysis of samples from the tank vapor space. It will be possible to detect a wide range of hydrogen from parts per million to percent by volume, as well as other gas species suspected to be generated in waste tanks.

  4. Hydrogen Gas Sensors Based on Semiconductor Oxide Nanostructures

    PubMed Central

    Gu, Haoshuang; Wang, Zhao; Hu, Yongming

    2012-01-01

    Recently, the hydrogen gas sensing properties of semiconductor oxide (SMO) nanostructures have been widely investigated. In this article, we provide a comprehensive review of the research progress in the last five years concerning hydrogen gas sensors based on SMO thin film and one-dimensional (1D) nanostructures. The hydrogen sensing mechanism of SMO nanostructures and some critical issues are discussed. Doping, noble metal-decoration, heterojunctions and size reduction have been investigated and proved to be effective methods for improving the sensing performance of SMO thin films and 1D nanostructures. The effect on the hydrogen response of SMO thin films and 1D nanostructures of grain boundary and crystal orientation, as well as the sensor architecture, including electrode size and nanojunctions have also been studied. Finally, we also discuss some challenges for the future applications of SMO nanostructured hydrogen sensors. PMID:22778599

  5. Toward understanding and modeling of impurity gettering in silicon

    SciTech Connect

    Tan, Teh Y.; Gafiteanu, R.; Goesele, U.M.

    1995-08-01

    Gettering of harmful impurities away from the device active regions has already become an integral part of manufacturing integrated circuits (IC) using Czochralski (CZ) Si wafers, and is experiencing an increasing importance in Si solar cell fabrications for improving the cell efficiency. Gettering consists of (1) the creation of suitable gettering sites; and (2) the gettering processes of contaminants. Requirements for successful gettering differ between the IC and solar cell cases, because ICs are monolithic devices situated at the Si wafer surfaces while solar cells are bulk devices, and because the Si substrate materials used are different. For IC fabrications, the method used is that of intrinsic or internal gettering (IG) which utilizes oxygen precipitates and their associated defects in the CZ Si wafer bulk as gettering sites. Because of the bulk nature of IG sites, the scheme cannot be used also for solar cells. Only some kind of extrinsic or external gettering (EG) schemes with gettering sites located at the wafer surface regions can be used for solar cells. The gettering of the harmful contaminants, usually metals, to the gettering region involves the metal dissolution from precipitated state, the metal atom diffusion to and the stabilization at the gettering sites. A mathematical model of the gettering process is presented.

  6. Hydrogen: another gas with therapeutic potential.

    PubMed

    George, James F; Agarwal, Anupam

    2010-01-01

    Cardinal and colleagues describe the use of molecular hydrogen, the most abundant molecule in the universe, as a treatment for chronic allograft nephropathy (CAN) in a rat model of kidney transplantation. They demonstrate that the addition of hydrogen to the drinking water results in a decrease in the severity of CAN and increased graft survival, and they provide evidence that the mechanism of action could be due to a reduction in reactive oxygen species.

  7. Method for making hydrogen rich gas from hydrocarbon fuel

    DOEpatents

    Krumpelt, M.; Ahmed, S.; Kumar, R.; Doshi, R.

    1999-07-27

    A method of forming a hydrogen rich gas from a source of hydrocarbon fuel in which the hydrocarbon fuel contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion at a temperature not less than about 400 C for a time sufficient to generate the hydrogen rich gas while maintaining CO content less than about 5 volume percent. There is also disclosed a method of forming partially oxidized hydrocarbons from ethanes in which ethane gas contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion for a time and at a temperature sufficient to form an oxide. 4 figs.

  8. Method for making hydrogen rich gas from hydrocarbon fuel

    DOEpatents

    Krumpelt, Michael; Ahmed, Shabbir; Kumar, Romesh; Doshi, Rajiv

    1999-01-01

    A method of forming a hydrogen rich gas from a source of hydrocarbon fuel in which the hydrocarbon fuel contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion at a temperature not less than about 400.degree. C. for a time sufficient to generate the hydrogen rich gas while maintaining CO content less than about 5 volume percent. There is also disclosed a method of forming partially oxidized hydrocarbons from ethanes in which ethane gas contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion for a time and at a temperature sufficient to form an oxide.

  9. Hydrogen Resource Assessment: Hydrogen Potential from Coal, Natural Gas, Nuclear, and Hydro Power

    SciTech Connect

    Milbrandt, A.; Mann, M.

    2009-02-01

    This paper estimates the quantity of hydrogen that could be produced from coal, natural gas, nuclear, and hydro power by county in the United States. The study estimates that more than 72 million tonnes of hydrogen can be produced from coal, natural gas, nuclear, and hydro power per year in the country (considering only 30% of their total annual production). The United States consumed about 396 million tonnes of gasoline in 2007; therefore, the report suggests the amount of hydrogen from these sources could displace about 80% of this consumption.

  10. Methanation of gas streams containing carbon monoxide and hydrogen

    DOEpatents

    Frost, Albert C.

    1983-01-01

    Carbon monoxide-containing gas streams having a relatively high concentration of hydrogen are pretreated so as to remove the hydrogen in a recoverable form for use in the second step of a cyclic, essentially two-step process for the production of methane. The thus-treated streams are then passed over a catalyst to deposit a surface layer of active surface carbon thereon essentially without the formation of inactive coke. This active carbon is reacted with said hydrogen removed from the feed gas stream to form methane. The utilization of the CO in the feed gas stream is appreciably increased, enhancing the overall process for the production of relatively pure, low-cost methane from CO-containing waste gas streams.

  11. Molecular processes in astrophysics: Calculations of hydrogen + hydrogen gas excitation, de-excitation, and cooling

    NASA Astrophysics Data System (ADS)

    Kelley, Matthew Thomas

    The implications of H+H2 cooling in astrophysics is important to several applications. One of the most significant and pure applications is its role in cooling in the early universe. Other applications would include molecular dynamics in nebulae and their collapse into stars and astrophysical shocks. Shortly after the big bang, the universe was a hot primordial gas of photons, electrons, and nuclei among other ingredients. By far the most dominant nuclei in the early universe was hydrogen. In fact, in the early universe the matter density was 90 percent hydrogen and only 10 percent helium with small amounts of lithium and deuterium. In order for structure to form in the universe, this primordial gas must form atoms and cool. One of the significant cooling mechanisms is the collision of neutral atomic hydrogen with a neutral diatomic hydrogen molecule. This work performs calculations to determine collisional cooling rates of hydrogen using two potential surfaces.

  12. Production of hydrogen by thermocatalytic cracking of natural gas

    SciTech Connect

    Muradov, N.Z.

    1995-09-01

    It is universally accepted that in the next few decades hydrogen production will continue to rely on fossil fuels (primarily, natural gas). On the other hand, the conventional methods of hydrogen production from natural gas (for example, steam reforming) are complex multi-step processes. These processes also result in the emission of large quantities of CO{sub 2} into the atmosphere that produce adverse ecological effects. One alternative is the one-step thermocatalytic cracking (TCC) (or decomposition) of natural gas into hydrogen and carbon. Preliminary analysis indicates that the cost of hydrogen produced by thermal decomposition of natural gas is somewhat lower than the conventional processes after by-product carbon credit is taken. In the short term, this process can be used for on-site production of hydrogen-methane mixtures in gas-filling stations and for CO{sub x}-free production of hydrogen for fuel cell driven prime movers. The experimental data on the thermocatalytic cracking of methane over various catalysts and supports in a wide range of temperatures (500-900{degrees}C) are presented in this paper. Two types of reactors were designed and built at FSEC: continuous flow and pulse fix bed catalytic reactors. The temperature dependence of the hydrogen production yield using oxide type catalysts was studied. Alumina-supported Ni- and Fe-catalysts demonstrated relatively high efficiency in the methane cracking reaction at moderate temperatures (600-800{degrees}C). Kinetic curves of hydrogen production over metal and metal oxide catalysts at different temperatures are presented in the paper. Fe-catalyst demonstrated good stability (for several hours), whereas alumina-supported Pt-catalyst rapidly lost its catalytic activity.

  13. Gas Permeable Chemochromic Compositions for Hydrogen Sensing

    NASA Technical Reports Server (NTRS)

    Bokerman, Gary (Inventor); Mohajeri, Nahid (Inventor); Muradov, Nazim (Inventor); Tabatabaie-Raissi, Ali (Inventor)

    2013-01-01

    A (H2) sensor composition includes a gas permeable matrix material intermixed and encapsulating at least one chemochromic pigment. The chemochromic pigment produces a detectable change in color of the overall sensor composition in the presence of H2 gas. The matrix material provides high H2 permeability, which permits fast permeation of H2 gas. In one embodiment, the chemochromic pigment comprises PdO/TiO2. The sensor can be embodied as a two layer structure with the gas permeable matrix material intermixed with the chemochromic pigment in one layer and a second layer which provides a support or overcoat layer.

  14. Refrigerated hydrogen gas jet for the Fermilab antiproton accumulator

    SciTech Connect

    Allspach, D.H.; Kendziora, C.L.; Marinelli, M.

    1995-07-01

    A hydrogen gas jet has been built for use at Fermilab for the study of charmonium spectroscopy in proton-antiproton annihilations. The hydrogen gas jet is part of an upgrade to a previous experiment which ran in the Fermilab 1990-1991 fixed target program utilizing a jet cooled to 80 K with liquid nitrogen. The jet delivers a defined stream of hydrogen gas which travels through a series of vacuum chambers and then intersects the circulating antiproton beam. The goal of the upgrade is to provide a hydrogen gas stream at least twice as dense as used for the earlier experiment to increase the interaction rate and allow an improved study of rare processes. This is achieved by cooling the stream to below 30 K using a Gifford-McMahon refrigerator. The jet apparatus is designed to allow motion in the plane perpendicular to the gas stream as well as angular positioning at the jet nozzle to provide a means of optimizing the interaction rate. Two skimmers located in the vacuum chambers are used to define the gas stream dimensions. The jet target vacuum chambers require constant pumping with turbomolecular pumps. The vacuum space around the jet is designed to have a large system pumping speed so that the chamber pressure can be maintained below an absolute pressure of 1 Pa. The jet will operate in the next fixed target run at Fermilab. Details of the design and test results are discussed.

  15. Recovery of purified helium or hydrogen from gas mixtures

    DOEpatents

    Merriman, J.R.; Pashley, J.H.; Stephenson, M.J.; Dunthorn, D.I.

    1974-01-15

    A process is described for the removal of helium or hydrogen from gaseous mixtures also containing contaminants. The gaseous mixture is contacted with a liquid fluorocarbon in an absorption zone maintained at superatomspheric pressure to preferentially absorb the contaminants in the fluorocarbon. Unabsorbed gas enriched in hydrogen or helium is withdrawn from the absorption zone as product. Liquid fluorocarbon enriched in contaminants is withdrawn separately from the absorption zone. (10 claims)

  16. Blending Hydrogen into Natural Gas Pipeline Networks. A Review of Key Issues

    SciTech Connect

    Melaina, M. W.; Antonia, O.; Penev, M.

    2013-03-01

    This study assesses the potential to deliver hydrogen through the existing natural gas pipeline network as a hydrogen and natural gas mixture to defray the cost of building dedicated hydrogen pipelines. Blending hydrogen into the existing natural gas pipeline network has also been proposed as a means of increasing the output of renewable energy systems such as large wind farms.

  17. Flashback Detection Sensor for Hydrogen Augmented Natural Gas Combustion

    SciTech Connect

    Thornton, J.D.; Chorpening, B.T.; Sidwell, T.; Strakey, P.A.; Huckaby, E.D.; Benson, K.J.

    2007-05-01

    The use of hydrogen augmented fuel is being investigated by various researchers as a method to extend the lean operating limit, and potentially reduce thermal NOx formation in natural gas fired lean premixed (LPM) combustion systems. The resulting increase in flame speed during hydrogen augmentation, however, increases the propensity for flashback in LPM systems. Real-time in-situ monitoring of flashback is important for the development of control strategies for use of hydrogen augmented fuel in state-of-the-art combustion systems, and for the development of advanced hydrogen combustion systems. The National Energy Technology Laboratory (NETL) and Woodward Industrial Controls are developing a combustion control and diagnostics sensor (CCADS), which has already been demonstrated as a useful sensor for in-situ monitoring of natural gas combustion, including detection of important combustion events such as flashback and lean blowoff. Since CCADS is a flame ionization sensor technique, the low ion concentration produced in pure hydrogen combustion raises concerns of whether CCADS can be used to monitor flashback in hydrogen augmented combustion. This paper discusses CCADS tests conducted at 0.2-0.6 MPa (2-6 atm), demonstrating flashback detection with fuel compositions up to 80% hydrogen (by volume) mixed with natural gas. NETL’s Simulation Validation (SimVal) combustor offers full optical access to pressurized combustion during these tests. The CCADS data and high-speed video show the reaction zone moves upstream into the nozzle as the hydrogen fuel concentration increases, as is expected with the increased flame speed of the mixture. The CCADS data and video also demonstrate the opportunity for using CCADS to provide the necessary in-situ monitor to control flashback and lean blowoff in hydrogen augmented combustion applications.

  18. Hydrogen Gas as a Fuel in Direct Injection Diesel Engine

    NASA Astrophysics Data System (ADS)

    Dhanasekaran, Chinnathambi; Mohankumar, Gabriael

    2016-04-01

    Hydrogen is expected to be one of the most important fuels in the near future for solving the problem caused by the greenhouse gases, for protecting environment and saving conventional fuels. In this study, a dual fuel engine of hydrogen and diesel was investigated. Hydrogen was conceded through the intake port, and simultaneously air and diesel was pervaded into the cylinder. Using electronic gas injector and electronic control unit, the injection timing and duration varied. In this investigation, a single cylinder, KIRLOSKAR AV1, DI Diesel engine was used. Hydrogen injection timing was fixed at TDC and injection duration was timed for 30°, 60°, and 90° crank angles. The injection timing of diesel was fixed at 23° BTDC. When hydrogen is mixed with inlet air, emanation of HC, CO and CO2 decreased without any emission (exhaustion) of smoke while increasing the brake thermal efficiency.

  19. Combustion gas properties. Part 3: Hydrogen gas fuel and dry air

    NASA Technical Reports Server (NTRS)

    Wear, J. D.; Jones, R. E.; Mcbride, B. J.; Beyerle, R. A.

    1985-01-01

    A series of computations has been made to produce the equilibrium temperature and gas composition for hydrogen gas fuel and dry air. The computed tables and figures provide combustion gas property data for pressures from 0.5 to 50 atmospheres and equivalence ratios from 0 to 2.0. Only sample tables and figures are provided in this report.

  20. Production of bioplastics and hydrogen gas by photosynthetic microorganisms

    NASA Astrophysics Data System (ADS)

    Yasuo, Asada; Masato, Miyake; Jun, Miyake

    1998-03-01

    Our efforts have been aimed at the technological basis of photosynthetic-microbial production of materials and an energy carrier. We report here accumulation of poly-(3-hydroxybutyrate) (PHB), a raw material of biodegradable plastics and for production of hydrogen gas, and a renewable energy carrier by photosynthetic microorganisms (tentatively defined as cyanobacteria plus photosynthetic bateria, in this report). A thermophilic cyanobacterium, Synechococcus sp. MA19 that accumulates PHB at more than 20% of cell dry wt under nitrogen-starved conditions was isolated and microbiologically identified. The mechanism of PHB accumulation was studied. A mesophilic Synechococcus PCC7942 was transformed with the genes encoding PHB-synthesizing enzymes from Alcaligenes eutrophus. The transformant accumulated PHB under nitrogen-starved conditions. The optimal conditions for PHB accumulation by a photosynthetic bacterium grown on acetate were studied. Hydrogen production by photosynthetic microorganisms was studied. Cyanobacteria can produce hydrogen gas by nitrogenase or hydrogenase. Hydrogen production mediated by native hydrogenase in cyanobacteria was revealed to be in the dark anaerobic degradation of intracellular glycogen. A new system for light-dependent hydrogen production was targeted. In vitro and in vivo coupling of cyanobacterial ferredoxin with a heterologous hydrogenase was shown to produce hydrogen under light conditions. A trial for genetic trasformation of Synechococcus PCC7942 with the hydrogenase gene from Clostridium pasteurianum is going on. The strong hydrogen producers among photosynthetic bacteria were isolated and characterized. Co-culture of Rhodobacter and Clostriumdium was applied to produce hydrogen from glucose. Conversely in the case of cyanobacteria, genetic regulation of photosynthetic proteins was intended to improve conversion efficiency in hydrogen production by the photosynthetic bacterium, Rhodobacter sphaeroides RV. A mutant acquired by

  1. Hydrogen Peroxide Gas Generator Cycle with a Reciprocating Pump

    SciTech Connect

    Whitehead, J C

    2002-06-11

    A four-chamber piston pump is powered by decomposed 85% hydrogen peroxide. The performance envelope of the evolving 400 gram pump has been expanded to 172 cc/s water flow at discharge pressures near 5 MPa. A gas generator cycle system using the pump has been tested under similar conditions of pressure and flow. The powerhead gas is derived from a small fraction of the pumped hydrogen peroxide, and the system starts from tank pressures as low as 0.2 MPa. The effects of steam condensation on performance have been evaluated.

  2. Gas storage materials, including hydrogen storage materials

    SciTech Connect

    Mohtadi, Rana F; Wicks, George G; Heung, Leung K; Nakamura, Kenji

    2013-02-19

    A material for the storage and release of gases comprises a plurality of hollow elements, each hollow element comprising a porous wall enclosing an interior cavity, the interior cavity including structures of a solid-state storage material. In particular examples, the storage material is a hydrogen storage material such as a solid state hydride. An improved method for forming such materials includes the solution diffusion of a storage material solution through a porous wall of a hollow element into an interior cavity.

  3. Gas storage materials, including hydrogen storage materials

    SciTech Connect

    Mohtadi, Rana F; Wicks, George G; Heung, Leung K; Nakamura, Kenji

    2014-11-25

    A material for the storage and release of gases comprises a plurality of hollow elements, each hollow element comprising a porous wall enclosing an interior cavity, the interior cavity including structures of a solid-state storage material. In particular examples, the storage material is a hydrogen storage material, such as a solid state hydride. An improved method for forming such materials includes the solution diffusion of a storage material solution through a porous wall of a hollow element into an interior cavity.

  4. Dominant factors of the laser gettering of silicon wafers

    SciTech Connect

    Bokhan, Yu. I. E-mail: yuibokhan@gmail.com; Kamenkov, V. S.; Tolochko, N. K.

    2015-02-15

    The laser gettering of silicon wafers is experimentally investigated. The typical gettering parameters are considered. The surfaces of laser-treated silicon wafers are investigated by microscopy. When studying the effect of laser radiation on silicon wafers during gettering, a group of factors determining the conditions of interaction between the laser beam and silicon-wafer surface and affecting the final result of treatment are selected. The main factors determining the gettering efficiency are revealed. Limitations on the desired value of the getter-layer capacity on surfaces with insufficiently high cleanness (for example, ground or matte) are established.

  5. Blending Hydrogen into Natural Gas Pipeline Networks: A Review of Key Issues

    SciTech Connect

    Melaina, M. W.; Antonia, O.; Penev, M.

    2013-03-01

    The United States has 11 distinct natural gas pipeline corridors: five originate in the Southwest, four deliver natural gas from Canada, and two extend from the Rocky Mountain region. This study assesses the potential to deliver hydrogen through the existing natural gas pipeline network as a hydrogen and natural gas mixture to defray the cost of building dedicated hydrogen pipelines.

  6. Hydrogen-air energy storage gas-turbine system

    NASA Astrophysics Data System (ADS)

    Schastlivtsev, A. I.; Nazarova, O. V.

    2016-02-01

    A hydrogen-air energy storage gas-turbine unit is considered that can be used in both nuclear and centralized power industries. However, it is the most promising when used for power-generating plants based on renewable energy sources (RES). The basic feature of the energy storage system in question is combination of storing the energy in compressed air and hydrogen and oxygen produced by the water electrolysis. Such a process makes the energy storage more flexible, in particular, when applied to RES-based power-generating plants whose generation of power may considerably vary during the course of a day, and also reduces the specific cost of the system by decreasing the required volume of the reservoir. This will allow construction of such systems in any areas independent of the local topography in contrast to the compressed-air energy storage gas-turbine plants, which require large-sized underground reservoirs. It should be noted that, during the energy recovery, the air that arrives from the reservoir is heated by combustion of hydrogen in oxygen, which results in the gas-turbine exhaust gases practically free of substances hazardous to the health and the environment. The results of analysis of a hydrogen-air energy storage gas-turbine system are presented. Its layout and the principle of its operation are described and the basic parameters are computed. The units of the system are analyzed and their costs are assessed; the recovery factor is estimated at more than 60%. According to the obtained results, almost all main components of the hydrogen-air energy storage gas-turbine system are well known at present; therefore, no considerable R&D costs are required. A new component of the system is the H2-O2 combustion chamber; a difficulty in manufacturing it is the necessity of ensuring the combustion of hydrogen in oxygen as complete as possible and preventing formation of nitric oxides.

  7. Detection of hydrogen chloride gas in air

    NASA Technical Reports Server (NTRS)

    Gregory, G. L.

    1978-01-01

    Launch vehicle effluent (LVE) monitoring is part of NASA's overall tropospheric and stratospheric environmental program. Following nine techniques are evaluated and developed in report: bubbler method, pH measurements, indicator tubes, microcoulometers, modified condensation nuclei counter, dual-isotope absorption, gas-filter correlation, chemiluminescent nitric oxide detection, chemiluminescent luminol-oxidation detection.

  8. Hydrogen Gas Presents a Promising Therapeutic Strategy for Sepsis

    PubMed Central

    Liu, Lingling; Yu, Yonghao; Wang, Guolin

    2014-01-01

    Sepsis is characterized by a severe inflammatory response to infection. It remains a major cause of morbidity and mortality in critically ill patients despite developments in monitoring devices, diagnostic tools, and new therapeutic options. Recently, some studies have found that molecular hydrogen is a new therapeutic gas. Our studies have found that hydrogen gas can improve the survival and organ damage in mice and rats with cecal ligation and puncture, zymosan, and lipopolysaccharide-induced sepsis. The mechanisms are associated with the regulation of oxidative stress, inflammatory response, and apoptosis, which might be through NF-κB and Nrf2/HO-1 signaling pathway. In this paper, we summarized the progress of hydrogen treatment in sepsis. PMID:24829918

  9. Dynamic gas bearing turbine technology in hydrogen plants

    NASA Astrophysics Data System (ADS)

    Ohlig, Klaus; Bischoff, Stefan

    2012-06-01

    Dynamic Gas Bearing Turbines - although applied for helium refrigerators and liquefiers for decades - experienced limitations for hydrogen applications due to restrictions in axial bearing capacity. With a new design concept for gas bearing turbines developed in 2004, axial bearing capacity was significantly improved enabling the transfer of this technology to hydrogen liquefiers. Prior to roll-out of the technology to industrial plants, the turbine bearing technology passed numerous tests in R&D test benches and subsequently proved industrial scale demonstration at Linde Gas' hydrogen liquefier in Leuna, Germany. Since its installation, this turbine has gathered more than 16,000 successful operating hours and has outperformed its oil bearing brother in terms of performance, maintainability as well as reliability. The present paper is based on Linde Kryotechnik AG's paper published in the proceedings of the CEC 2009 concerning the application of Dynamic Gas Bearing Turbines in hydrogen applications. In contrast to the former paper, this publication focuses on the steps towards final market launch and more specifically on the financial benefits of this turbine technology, both in terms of capital investment as well as operating expenses.

  10. Hydrogen and Oxygen Gas Monitoring System Design and Operation

    SciTech Connect

    Lee C. Cadwallader; Kevin G. DeWall; J. Stephen Herring

    2007-06-01

    This paper describes pertinent design practices of selecting types of monitors, monitor unit placement, setpoint selection, and maintenance considerations for gas monitors. While hydrogen gas monitors and enriched oxygen atmosphere monitors as they would be needed for hydrogen production experiments are the primary focus of this paper, monitors for carbon monoxide and carbon dioxide are also discussed. The experiences of designing, installing, and calibrating gas monitors for a laboratory where experiments in support of the DOE Nuclear Hydrogen Initiative (NHI) are described along with codes, standards, and regulations for these monitors. Information from the literature about best operating practices is also presented. The NHI program has two types of activities. The first, near-term activity is laboratory and pilot-plant experimentation with different processes in the kilogram per day scale to select the most promising types of processes for future applications of hydrogen production. Prudent design calls for indoor gas monitors to sense any hydrogen leaks within these laboratory rooms. The second, longer-term activity is the prototype, or large-scale plants to produce tons of hydrogen per day. These large, outdoor production plants will require area (or “fencepost”) monitoring of hydrogen gas leaks. Some processes will have oxygen production with hydrogen production, and any oxygen releases are also safety concerns since oxygen gas is the strongest oxidizer. Monitoring of these gases is important for personnel safety of both indoor and outdoor experiments. There is some guidance available about proper placement of monitors. The fixed point, stationary monitor can only function if the intruding gas contacts the monitor. Therefore, monitor placement is vital to proper monitoring of the room or area. Factors in sensor location selection include: indoor or outdoor site, the location and nature of potential vapor/gas sources, chemical and physical data of the

  11. Getter materials for cracking ammonia

    DOEpatents

    Boffito, Claudio; Baker, John D.

    1999-11-02

    A method is provided for cracking ammonia to produce hydrogen. The method includes the steps of passing ammonia over an ammonia-cracking catalyst which is an alloy including (1) alloys having the general formula Zr.sub.1-x Ti.sub.x M.sub.1 M.sub.2, wherein M.sub.1 and M.sub.2 are selected independently from the group consisting of Cr, Mn, Fe, Co, and Ni, and x is between about 0.0 and about 1.0 inclusive; and between about 20% and about 50% Al by weight. In another aspect, the method of the invention is used to provide methods for operating hydrogen-fueled internal combustion engines and hydrogen fuel cells. In still another aspect, the present invention provides a hydrogen-fueled internal combustion engine and a hydrogen fuel cell including the above-described ammonia-cracking catalyst.

  12. Silicon Carbide-Based Hydrogen and Hydrocarbon Gas Detection

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.; Neudeck, Philip G.; Chen, Liang-Yu; Knight, D.; Liu, C. C.; Wu, Q. H.R

    1995-01-01

    Hydrogen and hydrocarbon detection in aeronautical applications is important for reasons of safety and emissions control. The use of silicon carbide as a semiconductor in a metal-semiconductor or metal-insulator-semiconductor structure opens opportunities to measure hydrogen and hydrocarbons in high temperature environments beyond the capabilities of silicon-based devices. The purpose of this paper is to explore the response and stability of Pd-SiC Schottky diodes as gas sensors in the temperature range from 100 to 400 C. The effect of heat treating on the diode properties as measured at 100 C is explored. Subsequent operation at 400 C demonstrates the diodes' sensitivity to hydrogen and hydrocarbons. It is concluded that the Pd-SiC Schottky diode has potential as a hydrogen and hydrocarbon sensor over a wide range of temperatures but further studies are necessary to determine the diodes' long term stability.

  13. The sodium and hydrogen gas clouds of Io

    NASA Technical Reports Server (NTRS)

    Smyth, W. H.; Mcelroy, M. B.

    1977-01-01

    Models are developed to describe the spatial distribution of gases emitted by Io and are applied to recent observations which indicate extensive gas clouds of hydrogen and sodium in orbit around Jupiter. Hydrogen and sodium atoms are emitted from Io with velocities in the range from 2 to 3 km/sec, with fluxes of about 10 billion and 100 million per sq cm/sec for hydrogen and sodium, respectively. Hydrogen atoms may be formed by photodecomposition of gases such as NH3 or H2S released from the satellite surface and may escape thermally from an exosphere whose temperature is about 500 K. Sodium may be ejected from the surface by energetic particles or by ultraviolet radiation, and it appears that a nonthermal mechanism drawing energy from Jupiter's magnetic field is required in order to account for its release to space.

  14. Absorption media for irreversibly gettering thionyl chloride

    DOEpatents

    Buffleben, George; Goods, Steven H.; Shepodd, Timothy; Wheeler, David R.; Whinnery, Jr., LeRoy

    2002-01-01

    Thionyl chloride is a hazardous and reactive chemical used as the liquid cathode in commercial primary batteries. Contrary to previous thinking, ASZM-TEDA.RTM. carbon (Calgon Corporation) reversibly absorbs thionyl chloride. Thus, several candidate materials were examined as irreversible getters for thionyl chloride. The capacity, rate and effect of temperature were also explored. A wide variety of likely materials were investigated through screening experiments focusing on the degree of heat generated by the reaction as well as the material absorption capacity and irreversibility, in order to help narrow the group of possible getter choices. More thorough, quantitative measurements were performed on promising materials. The best performing getter was a mixture of ZnO and ASZM-TEDA.RTM. carbon. In this example, the ZnO reacts with thionyl chloride to form ZnCl.sub.2 and SO.sub.2. The SO.sub.2 is then irreversibly gettered by ASZM-TEDA.RTM. carbon. This combination of ZnO and carbon has a high capacity, is irreversible and functions effectively above -20.degree. C.

  15. Technetium getters in the near surface environment

    SciTech Connect

    KRUMHANSL,JAMES L.; ZHANG,PENGCHU; WESTRICH,HENRY R.; BRYAN,CHARLES R.; MOLECKE,MARTIN A.

    2000-05-19

    Conventional performance assessments assume that radioactive {sup 99}Tc travels as a non-sorbing component with an effective K{sub d} (distribution coefficient) of 0. This is because soil mineral surfaces commonly develop net negative surface charges and pertechnetate (TcO{sub 4}), with large ionic size and low electrical density, is not sorbed onto them. However, a variety of materials have been identified that retain Tc and may eventually lead to promising Tc getters. In assessing Tc getter performance it is important to evaluate the environment in which the getter is to function. In many contaminant plumes Tc will only leach slowly from the source of the contamination and significant dilution is likely. Thus, sub-ppb Tc concentrations are expected and normal groundwater constituents will dominate the aquifer chemistry. In this setting a variety of constituents were found to retard TcO{sub 4}: imogolite, boehmite, hydrotalcite, goethite, copper sulfide and oxide and coal. Near leaking tanks of high level nuclear waste, Tc may be present in mg/L level concentrations and groundwater chemistry will be dominated by constituents from the waste. Both bone char, and to a lesser degree, freshly precipitated Al hydroxides may be effective Tc scavengers in this environment. Thus, the search for Tc getters is far from hopeless, although much remains to be learned about the mechanisms by which these materials retain Tc.

  16. Hydrogenation Reactions during Pyrolysis-Gas Chromatography/Mass Spectrometry Analysis of Polymer Samples Using Hydrogen Carrier Gas.

    PubMed

    Watanabe, Atsushi; Watanabe, Chuichi; Freeman, Robert R; Teramae, Norio; Ohtani, Hajime

    2016-05-17

    Pyrolysis-gas chromatography/mass spectrometry of polymer samples is studied focusing on the effect of hydrogen (H2) carrier gas on chromatographic and spectral data. The pyrograms and the related mass spectra of high density polyethylene (HDPE), low density polyethylene, and polystyrene (PS) serve to illustrate the differences between the species formed in H2 and the helium environment. Differences in the pyrograms and the spectra are generally thought to be a result of the hydrogenation reaction of the pyrolyzates. From the peak intensity changes in the pyrograms of HDPE and PS, hydrogenation of unsaturated pyrolyzates is concluded to occur when the pyrolysis is done in H2. Moreover, additional hydrogenation of the pyrolyzates occurs in the electron ionization source of a MS detector when H2 is used as a carrier gas. Finally, the applicability of mass spectral libraries to characterize pyrograms obtained in H2 is illustrated using 24 polymers. The effect of the hydrogenation reaction on the library search results is found to be negligible for most polymer samples with polar and nonpolar monomer units. PMID:27125864

  17. Production of hydrogen by thermocatalytic cracking of natural gas

    SciTech Connect

    Muradov, N.

    1996-10-01

    The conventional methods of hydrogen production from natural gas (for example, steam reforming and partial oxidation) are complex, multi-step processes that produce large quantities of CO{sub 2}. The main goal of this project is to develop a technologically simple process for hydrogen production from natural gas (NG) and other hydrocarbon fuels via single-step decomposition of hydrocarbons. This approach eliminates or significantly reduces CO{sub 2} emission. Carbon is a valuable by-product of this process, whereas conventional methods of hydrogen production from NG produce no useful by-products. This approach is based on the use of special catalysts that reduce the maximum temperature of the process from 1400-1500{degrees}C (thermal non-catalytic decomposition of methane) to 500-900{degrees}C. Transition metal based catalysts and various forms of carbon are among the candidate catalysts for the process. This approach can advantageously be used for the development of compact NG reformers for on-site production of hydrogen-methane blends at refueling stations and, also, for the production of hydrogen-rich gas for fuel cell applications. The author extended the search for active methane decomposition catalysts to various modifications of Ni-, Fe-, Mo- and Co-based catalysts. Variation in the operational parameters makes it possible to produce H{sub 2}-CH{sub 4} blends with a wide range of hydrogen concentrations that vary from 15 to 98% by volume. The author found that Ni-based catalysts are more effective at temperatures below 750{degrees}C, whereas Fe-based catalysts are effective at temperatures above 800{degrees}C for the production of hydrogen with purity of 95% v. or higher. The catalytic pyrolysis of liquid hydrocarbons (pentane, gasoline) over Fe-based catalyst was conducted. The author observed the production of a hydrogen-rich gas (hydrogen concentration up to 97% by volume) at a rate of approximately 1L/min.mL of hydrocarbon fuel.

  18. Onboard Plasmatron Generation of Hydrogen rich Gas for Diesel Engine Exhaust Aftertreatment and Other Applications

    SciTech Connect

    Bromberg, L.; Cohn, D.R.; Heywood,J.; Rabinovich, A.

    2002-08-25

    Plasmatron reformers can provide attractive means for conversion of diesel fuel into hydrogen rich gas. The hydrogen rich gas can be used for improved NOx trap technology and other aftertreatment applications.

  19. Investigation into the hydrogen gas sensing mechanism of cubic silicon carbide resistive gas sensors

    NASA Astrophysics Data System (ADS)

    Fawcett, Timothy J.

    The hydrogen (H2) gas sensing mechanism driving 3C-SiC resistive gas sensors is investigated in this work in which two hypotheses are proposed. One hypothesis involves the surface adsorption of H2 on the sensor surface with the adsorbed molecules influencing the flow of current in a resistive gas sensor, termed the surface adsorption detection mechanism. The second hypothesis includes the transfer of heat from the sensor to the gas, producing a change in the temperature of the device when the heat transfer characteristics of the gas change, termed the thermal detection mechanism. The heat transfer characteristics of the gas are dependent on the thermal conductivity of the gas, a property which is a strong function of gas composition. Thus, the thermal detection mechanism mainly detects changes in the thermal conductivity of a gas or gas mixture. Initial experiments suggested the surface adsorption mechanism as the detection mechanism of resistive 3C-SiC gas sensors. However, these experiments were performed in the absence of device temperature measurements. Recent experiments in which the device temperature was measured with a resistance temperature detector (RTD) in thermal contact with the device strongly support the thermal detection mechanism as being responsible for hydrogen gas detection. Experimental observations show the temperature of the resistive 3C-SiC hydrogen gas sensors changes greatly with changing hydrogen gas composition. For example, a 3C-SiC/SOI resistive sensor biased at 10 Vdc displayed a change in temperature from ˜400°C to ˜216°C, correlating to a change in current from ˜41 mA to ˜6mA, upon the introduction of 100% H2. The this 3C-SiC/SOI resistive sensor, this large decrease in temperature caused a large increase in resistance which is detected as a decrease in current. Several different experiments have also been performed to confirm the thermal detection mechanism hypothesis.

  20. Polymer formulation for removing hydrogen and liquid water from an enclosed space

    DOEpatents

    Shepodd, Timothy J.

    2006-02-21

    This invention describes a solution to the particular problem of liquid water formation in hydrogen getters exposed to quantities of oxygen. Water formation is usually desired because the recombination reaction removes hydrogen without affecting gettering capacity and the oxygen removal reduces the chances for a hydrogen explosion once free oxygen is essentially removed. The present invention describes a getter incorporating a polyacrylate compound that can absorb up to 500% of its own weight in liquid water without significantly affecting its hydrogen gettering/recombination properties, but that also is insensitive to water vapor.

  1. Hydrogen and Hydrogen/Natural Gas Station and Vehicle Operations - 2006 Summary Report

    SciTech Connect

    Francfort; Donald Karner; Roberta Brayer

    2006-09-01

    This report is a summary of the operations and testing of internal combustion engine vehicles that were fueled with 100% hydrogen and various blends of hydrogen and compressed natural gas (HCNG). It summarizes the operations of the Arizona Public Service Alternative Fuel Pilot Plant, which produces, compresses, and dispenses hydrogen fuel. Other testing activities, such as the destructive testing of a CNG storage cylinder that was used for HCNG storage, are also discussed. This report highlights some of the latest technology developments in the use of 100% hydrogen fuels in internal combustion engine vehicles. Reports are referenced and WWW locations noted as a guide for the reader that desires more detailed information. These activities are conducted by Arizona Public Service, Electric Transportation Applications, the Idaho National Laboratory, and the U.S. Department of Energy’s Advanced Vehicle Testing Activity.

  2. Biomass & Natural Gas Based Hydrogen Fuel For Gas Turbine (Power Generation)

    EPA Science Inventory

    Significant progress has been made by major power generation equipment manufacturers in the development of market applications for hydrogen fuel use in gas turbines in recent years. Development of a new application using gas turbines for significant reduction of power plant CO2 e...

  3. Erosion of graphite surface exposed to hot supersonic hydrogen gas

    NASA Technical Reports Server (NTRS)

    Sharma, O. P.

    1972-01-01

    A theoretical model based on laminar boundary layer flow equations is developed to predict the erosion rate of a graphite (AGCarb-101) surface exposed to a hot supersonic stream of hydrogen gas. The supersonic flow in the nozzle outside the boundary layer formed over the surface of the specimen is determined by assuming one-dimensional isentropic conditions. An overall surface reaction rate expression based on the experimental studies by Clarke and Fox is used to describe the interaction of hydrogen with graphite. A satisfactory agreement is found between the results of the computation, and the available experimental data. Some shortcomings of the model, and further possible improvements are discussed.

  4. Hydrogen gas embrittlement and the disc pressure test

    NASA Technical Reports Server (NTRS)

    Bachelet, E. J.; Troiano, A. R.

    1973-01-01

    A disc pressure test has been used to study the influenced of a hydrogen gas environment on the mechanical properties of three high strength superalloys, Inconel 718, L-605 and A-286, in static and dynamic conditions. The influence of the hydrogen pressure, loading rate, temperature, mechanical and thermal fatigue has investigated. The permeation characteristics of Inconel 718 have been determined in collaboration with the French AEC. The results complemented by a fractographic study are consistent either with a stress-sorption or with an internal embrittlement type of mechanism.

  5. Instruction manual for UTEP weld gas hydrogen detector

    NASA Technical Reports Server (NTRS)

    Mcclure, John; Pang, Tonghui

    1992-01-01

    The instrument described in this manual was developed at the University of Texas at El Paso under contract from the National Aeronautics and Space Administration Marshall Space Flight Center. The instrument has been used to detect hydrogen in the shielding gas of Variable Polarity Plasma Arc (VPPA) welds at concentrations of less than 100 ppm. The instrument makes measurements in real time during the welding operation and provides the operator with an easily readable graphic display of the present level of hydrogen in the arc as well as the level of hydrogen over the past approximately five minutes. In this way the welder can not only tell if the present level of hydrogen is excessive, but can see what changes in weld parameters have done to the level of hydrogen. The welder can set the level of hydrogen that is considered critical and the instrument display will indicate when that level has been exceeded. All detection is from the torch side. All needed equipment is supplied by the developer except for an IBM PC compatible computer which must be supplied by the user. Source code is supplied in this manual so that the user can modify the control program as desired.

  6. Disposal pathway for tritiated reactive metals and tritiated hydrogen gas

    SciTech Connect

    Antoniazzi, A. B.; Morton, C. S.

    2008-07-15

    Kinectrics and its predecessor company Ontario Hydro Research Div. (a division of Ontario Hydro) had a fully operational tritium laboratory on site since the early 1980's. During those years numerous projects and experiments were undertaken using hydrogen and tritium for the most part. Metals with an affinity for hydrogen are commonly employed as scavengers of hydrogenic gases from process streams or as hydrogen storage mediums. The two most common of these metals used were depleted uranium and a zirconium-iron alloy (SAES St198). The break-up of Ontario Hydro through deregulation activities resulted in the building of a new, smaller, tritium laboratory and the decommissioning of the original tritium laboratory. Decommissioning activities resulted in the need to safely dispose of these reactive metals. Disposal of these metals is not straight forward. For safe, long term, disposal it has been decided to oxidize the metals in a controlled fashion. The oxidized beds, containing the metals, will be sent to a radioactive waste site for long term storage. Options for disposal of tritiated hydrogen gas are presented and discussed. This paper provides a disposal pathway for tritiated reactive metals and hydrogen thereby closing the loop in tritium handling. (authors)

  7. Argon-Hydrogen Shielding Gas Mixtures for Activating Flux-Assisted Gas Tungsten Arc Welding

    NASA Astrophysics Data System (ADS)

    Huang, Her-Yueh

    2010-11-01

    Using activating flux for gas tungsten arc welding (GTAW) to improve penetration capability is a well-established technique. Argon is an inert gas and the one most widely used as a shielding gas for GTAW. For the most austenitic stainless steels, pure argon does not provide adequate weld penetration. Argon-hydrogen mixtures give a more even heat input to the workpiece, increasing the arc voltage, which tends to increase the volume of molten material in the weld pool as well as the weld depth-to-width ratio. Great interest has been shown in the interaction between activating flux and the hydrogen concentration in an argon-based shielding gas. In this study, the weld morphology, the arc profile, the retained delta ferrite content, the angular distortion, and the microstructures were examined. The application of an activating flux combining argon and hydrogen for GTAW is important in the industry. The results of this study are presented here.

  8. Process for removal of hydrogen sulfide from gas streams

    SciTech Connect

    Hansford, R.C.; Hass, R.H.

    1981-01-06

    A process for the removal of H/sub 2/S from a feed gas, and the production of sulfur therefrom, is effected by oxidation with oxygen and/or SO/sub 2/ at temperatures between 250* and 450* F. The oxidation is conducted in the presence of an extremely stable oxidation catalyst comprising an oxide and/or sulfide of vanadium supported on a non-alkaline porous refractory oxide. Sulfur deposition and consequent catalyst deactivation are prevented by maintaining the partial pressure of free sulfur in the oxidation reactor below that necessary for condensation. H/sub 2/, CO, and light hydrocarbons present in the feed gas are not oxidized. Typical uses of the process include the removal of H/sub 2/S and the production of sulfur from sour natural gases or gases obtained from the gasification of coal. Feed gases which contain SO/sub 2/ and H/sub 2/S in mole ratios greater than 5, or which contain other gaseous sulfur compounds such as CO, CS/sub 2/, SO/sub 3/ and mercaptans, can be desulfurized by hydrogenating all of such sulfur components to H/sub 2/S and subsequently removing the H/sub 2/S from the hydrogenated feed gas by the oxidation process of the invention. This hydrogenation-oxidation combination is especially contemplated for the desulfurization of claus tail gases and stack gas effluents.

  9. Process for removal of hydrogen sulfide from gas streams

    SciTech Connect

    Hansford, R.C.; Hass, R.H.

    1982-01-19

    A process for the removal of H2S from a feed gas, and the production of sulfur therefrom, is effected by oxidation with oxygen and/or SO2 at temperatures between 250 and 450/sup 0/F. The oxidation is conducted in the presence of an extremely stable oxidation catalyst comprising an oxide and/or sulfide of vanadium supported on a non-alkaline porous refractory oxide. Sulfur deposition and consequent catalyst deactivation are prevented by maintaining the partial pressure of free sulfur in the oxidation reactor below that necessary for condensation. H2, CO, and light hydrocarbons present in the feed gas are not oxidized. Typical uses of the process include the removal of H2S and the production of sulfur from sour natural gases or gases obtained from the gasification of coal. Feed gases which contain SO2 and H2S in mole ratios greater than 5, or which contain other gaseous sulfur compounds such as CO CS2, SO3 and mercaptans, can be desulfurized by hydrogenating all of such sulfur components to H2S and subsequently removing the H2S from the hydrogenated feed gas by the oxidation process of the invention. This hydrogenation-oxidation combination is especially contemplated for the desulfurization of claus tail gases and stack gas effluents.

  10. LOX vaporization in high-pressure, hydrogen-rich gas

    NASA Technical Reports Server (NTRS)

    Litchford, Ron J.; Jeng, San-Mou

    1990-01-01

    LOX droplet vaporization in high-pressure hydrogen-rich gas is analyzed, with special attention to thermodynamic effects which compel the surface to heat to the critical state and to supercritical vaporization processes on heating to criticality. Subcritical vaporization is modeled using a quasi-steady diffusion-controlled gas-phase transport formulation coupled to an effective-conductivity internal-energy-transport model accounting for circulation effects. It is demonstrated how the droplet surface might heat to the critical state, for ambient pressures slightly greater than the critical pressure of oxygen, such that the bulk of propellant within the droplet remains substantially below the critical mixing temperature.

  11. Laser Raman sensor for measurement of trace-hydrogen gas

    NASA Technical Reports Server (NTRS)

    Adler-Golden, Steven M.; Goldstein, Neil; Bien, Fritz; Matthew, Michael W.; Gersh, Michael E.; Cheng, Wai K.; Adams, Frederick W.

    1992-01-01

    A new optical hydrogen sensor based on spontaneous Raman scattering of laser light has been designed and constructed for rugged field use. It provides good sensitivity, rapid response, and the inherent Raman characteristics of linearity and background gas independence of the signal. Efficient light collection and discrimination by using fast optics and a bandpass interference filter compensate for the inefficiency of the Raman-scattering process. A multipass optical cavity with a Herriott-type configuration provides intense illumination from an air-cooled CW gas laser. The observed performance is in good agreement with the theoretical signal and noise level predictions.

  12. Structure of Palladium Nanoclusters for Hydrogen Gas Sensors

    SciTech Connect

    Stevens, K.J.; Ingham, B.; Toney, M.F.; Brown, S.A.; Lassesson, A.; /SLAC, SSRL /Canterbury U.

    2009-05-11

    Palladium nanoclusters produced by inert gas aggregation/magnetron sputtering are used as building blocks for the construction of nano electronic devices with large surface to volume ratios that can be used as sensitive hydrogen gas sensors in fuel cells and in petrochemical plants. X-ray diffraction (XRD), extended X-ray absorption fine structure (EXAFS), and high resolution transmission electron microscopy (HRTEM) have been used to characterize the structure, lattice constant, particle diameter and oxide thickness of the palladium nanoclusters in order to understand the operation of these sensors. Grazing incidence XRD (GIXRD) of heat treated Pd clusters has shown that the palladanite structure forms at elevated temperatures.

  13. Effects of shielding gas hydrogen content on the arc behavior in gas tungsten arc welding

    SciTech Connect

    Onsoien, M.I.; Olson, D.L.; Liu, S.

    1994-12-31

    The primary role of the shielding gas in gas tungsten arc welding (GTAW) is to protect the weld pool and tungsten electrode from the oxygen and nitrogen in the surrounding atmosphere. Traditionally inert gases such as argon and helium have been used, either as pure gases or mixed with each other. However, additions of small amounts of hydrogen have been reported to improve weld bead penetration and enable higher welding speeds to be used. The present work was performed to investigate the effect of small hydrogen additions on the arc behavior in GTAW, and to further the fundamental understanding of the effect of shielding gas on arc characteristics. GTAW bead-on-plate welds were made on 12.5 mm x 150 mm x 75 mm Type 304 stainless steel test coupons. The welding current, voltage, and their variations were continuously monitored during welding. After welding, each test coupon was sectioned and prepared using standard metallographic techniques and etched in Vilella`s etch for macroexamination of the weld bead cross section. Bead width, depth, and cross-sectional area were measured using a LECO image analysator system. The influence of hydrogen content in an argon has tungsten arc was characterized. The electrical behavior of the arc, including the arc resistance, was measured as a function of current and hydrogen content. A better fundamental understanding of arc behavior and energy transfer was achieved using these experimental gas mixes. The results allow the following conclusions to be drawn: (1) Small additions of hydrogen in the argon based shielding gas in gas tungsten arc welding significantly change the weld bead geometry due to changes in the arc column. (2) Selection of the right argon, hydrogen shielding gas mixture to give the optimum arc column characteristics for a given condition can improve weld quality and increase productivity. (3) The resistance of the arc column was found to be an adequate parameter to describe the arc column behavior.

  14. Warm Pressurant Gas Effects on the Liquid Hydrogen Bubble Point

    NASA Technical Reports Server (NTRS)

    Hartwig, Jason W.; McQuillen, John B.; Chato, David J.

    2013-01-01

    This paper presents experimental results for the liquid hydrogen bubble point tests using warm pressurant gases conducted at the Cryogenic Components Cell 7 facility at the NASA Glenn Research Center in Cleveland, Ohio. The purpose of the test series was to determine the effect of elevating the temperature of the pressurant gas on the performance of a liquid acquisition device. Three fine mesh screen samples (325 x 2300, 450 x 2750, 510 x 3600) were tested in liquid hydrogen using cold and warm noncondensible (gaseous helium) and condensable (gaseous hydrogen) pressurization schemes. Gases were conditioned from 0 to 90 K above the liquid temperature. Results clearly indicate a degradation in bubble point pressure using warm gas, with a greater reduction in performance using condensable over noncondensible pressurization. Degradation in the bubble point pressure is inversely proportional to screen porosity, as the coarsest mesh demonstrated the highest degradation. Results here have implication on both pressurization and LAD system design for all future cryogenic propulsion systems. A detailed review of historical heated gas tests is also presented for comparison to current results.

  15. EUV tools: hydrogen gas purification and recovery strategies

    NASA Astrophysics Data System (ADS)

    Landoni, Cristian; Succi, Marco; Applegarth, Chuck; Riddle Vogt, Sarah

    2015-03-01

    The technological challenges that have been overcome to make extreme ultraviolet lithography (EUV) a reality have been enormous1. This vacuum driven technology poses significant purity challenges for the gases employed for purging and cleaning the scanner EUV chamber and source. Hydrogen, nitrogen, argon and ultra-high purity compressed dry air (UHPCDA) are the most common gases utilized at the scanner and source level. Purity requirements are tighter than for previous technology node tools. In addition, specifically for hydrogen, EUV tool users are facing not only gas purity challenges but also the need for safe disposal of the hydrogen at the tool outlet. Recovery, reuse or recycling strategies could mitigate the disposal process and reduce the overall tool cost of operation. This paper will review the types of purification technologies that are currently available to generate high purity hydrogen suitable for EUV applications. Advantages and disadvantages of each purification technology will be presented. Guidelines on how to select the most appropriate technology for each application and experimental conditions will be presented. A discussion of the most common approaches utilized at the facility level to operate EUV tools along with possible hydrogen recovery strategies will also be reported.

  16. Ionization-Assisted Getter Pumping for Ultra-Stable Trapped Ion Frequency Standards

    NASA Technical Reports Server (NTRS)

    Tjoelker, Robert L.; Burt, Eric A.

    2010-01-01

    A method eliminates (or recovers from) residual methane buildup in getter-pumped atomic frequency standard systems by applying ionizing assistance. Ultra-high stability trapped ion frequency standards for applications requiring very high reliability, and/or low power and mass (both for ground-based and space-based platforms) benefit from using sealed vacuum systems. These systems require careful material selection and system processing (cleaning and high-temperature bake-out). Even under the most careful preparation, residual hydrogen outgassing from vacuum chamber walls typically limits the base pressure. Non-evaporable getter pumps (NEGs) provide a convenient pumping option for sealed systems because of low mass and volume, and no power once activated. An ion gauge in conjunction with a NEG can be used to provide a low mass, low-power method for avoiding the deleterious effects of methane buildup in high-performance frequency standard vacuum systems.

  17. Revisions to the hydrogen gas generation computer model

    SciTech Connect

    Jerrell, J.W.

    1992-08-31

    Waste Management Technology has requested SRTC to maintain and extend a previously developed computer model, TRUGAS, which calculates hydrogen gas concentrations within the transuranic (TRU) waste drums. TRUGAS was written by Frank G. Smith using the BASIC language and is described in the report A Computer Model of gas Generation and Transport within TRU Waste Drums (DP- 1754). The computer model has been partially validated by yielding results similar to experimental data collected at SRL and LANL over a wide range of conditions. The model was created to provide the capability of predicting conditions that could potentially lead to the formation of flammable gas concentrations within drums, and to assess proposed drum venting methods. The model has served as a tool in determining how gas concentrations are affected by parameters such as filter vent sizes, waste composition, gas generation values, the number and types of enclosures, water instrusion into the drum, and curie loading. The success of the TRUGAS model has prompted an interest in the program's maintenance and enhancement. Experimental data continues to be collected at various sites on such parameters as permeability values, packaging arrangements, filter designs, and waste contents. Information provided by this data is used to improve the accuracy of the model's predictions. Also, several modifications to the model have been made to enlarge the scope of problems which can be analyzed. For instance, the model has been used to calculate hydrogen concentrations inside steel cabinets containing retired glove boxes (WSRC-RP-89-762). The revised TRUGAS computer model, H2GAS, is described in this report. This report summarizes all modifications made to the TRUGAS computer model and provides documentation useful for making future updates to H2GAS.

  18. Revisions to the hydrogen gas generation computer model

    SciTech Connect

    Jerrell, J.W.

    1992-08-31

    Waste Management Technology has requested SRTC to maintain and extend a previously developed computer model, TRUGAS, which calculates hydrogen gas concentrations within the transuranic (TRU) waste drums. TRUGAS was written by Frank G. Smith using the BASIC language and is described in the report A Computer Model of gas Generation and Transport within TRU Waste Drums (DP- 1754). The computer model has been partially validated by yielding results similar to experimental data collected at SRL and LANL over a wide range of conditions. The model was created to provide the capability of predicting conditions that could potentially lead to the formation of flammable gas concentrations within drums, and to assess proposed drum venting methods. The model has served as a tool in determining how gas concentrations are affected by parameters such as filter vent sizes, waste composition, gas generation values, the number and types of enclosures, water instrusion into the drum, and curie loading. The success of the TRUGAS model has prompted an interest in the program`s maintenance and enhancement. Experimental data continues to be collected at various sites on such parameters as permeability values, packaging arrangements, filter designs, and waste contents. Information provided by this data is used to improve the accuracy of the model`s predictions. Also, several modifications to the model have been made to enlarge the scope of problems which can be analyzed. For instance, the model has been used to calculate hydrogen concentrations inside steel cabinets containing retired glove boxes (WSRC-RP-89-762). The revised TRUGAS computer model, H2GAS, is described in this report. This report summarizes all modifications made to the TRUGAS computer model and provides documentation useful for making future updates to H2GAS.

  19. Integrated Micro-Machined Hydrogen Gas Sensor. Final Report

    SciTech Connect

    Frank DiMeo, Jr.

    2000-10-02

    This report details our recent progress in developing novel MEMS (Micro-Electro-Mechanical Systems) based hydrogen gas sensors. These sensors couple novel thin films as the active layer on a device structure known as a Micro-HotPlate. This coupling has resulted in a gas sensor that has several unique advantages in terms of speed, sensitivity, stability and amenability to large scale manufacture. This Phase-I research effort was focused on achieving the following three objectives: (1) Investigation of sensor fabrication parameters and their effects on sensor performance. (2) Hydrogen response testing of these sensors in wet/dry and oxygen-containing/oxygen-deficient atmospheres. (3) Investigation of the long-term stability of these thin film materials and identification of limiting factors. We have made substantial progress toward achieving each of these objectives, and highlights of our phase I results include the demonstration of signal responses with and without oxygen present, as well as in air with a high level of humidity. We have measured response times of <0.5 s to 1% H{sub 2} in air, and shown the ability to detect concentrations of <200 ppm. These results are extremely encouraging and suggest that this technology has substantial potential for meeting the needs of a hydrogen based economy. These achievements demonstrate the feasibility of using micro-hotplates structures in conjunction with palladium+coated metal-hydride films for sensing hydrogen in many of the environments required by a hydrogen based energy economy. Based on these findings, they propose to continue and expand the development of this technology in Phase II.

  20. Electrochemical separation and concentration of hydrogen sulfide from gas mixtures

    DOEpatents

    Winnick, Jack; Sather, Norman F.; Huang, Hann S.

    1984-10-30

    A method of removing sulfur oxides of H.sub.2 S from high temperature gas mixtures (150.degree.-1000.degree. C.) is the subject of the present invention. An electrochemical cell is employed. The cell is provided with inert electrodes and an electrolyte which will provide anions compatible with the sulfur containing anions formed at the anode. The electrolyte is also selected to provide inert stable cations at the temperatures encountered. The gas mixture is passed by the cathode where the sulfur gases are converted to SO.sub.4 -- or, in the case of H.sub.2 S, to S--. The anions migrate to the anode where they are converted to a stable gaseous form at much greater concentration levels (>10X). Current flow may be effected by utilizing an external source of electrical energy or by passing a reducing gas such as hydrogen past the anode.

  1. ELECTROCHEMICAL SEPARATION AND CONCENTRATION OF HYDROGEN SULFIDE FROM GAS MIXTURES

    DOEpatents

    Winnick, Jack; Sather, Norman F.; Huang, Hann S.

    1984-10-30

    A method of removing sulfur oxides of H.sub.2 S from high temperature gas mixtures (150.degree.-1000.degree. C.) is the subject of the present invention. An electrochemical cell is employed. The cell is provided with inert electrodes and an electrolyte which will provide anions compatible with the sulfur containing anions formed at the anode. The electrolyte is also selected to provide inert stable cations at the temperatures encountered. The gas mixture is passed by the cathode where the sulfur gases are converted to SO.sub.4 -- or, in the case of H.sub.2 S, to S--. The anions migrate to the anode where they are converted to a stable gaseous form at much greater concentration levels (>10X). Current flow may be effected by utilizing an external source of electrical energy or by passing a reducing gas such as hydrogen past the anode.

  2. WATER-GAS SHIFT WITH INTEGRATED HYDROGEN SEPARATION

    SciTech Connect

    Maria Flytzani-Stephanopoulos; Jerry Meldon; Xiaomei Qi

    2001-12-01

    Optimization of the water-gas shift (WGS) reaction system for hydrogen production for fuel cells is of particular interest to the energy industry. To this end, it is desirable to couple the WGS reaction to hydrogen separation using a semi-permeable membrane, with both processes carried out at high temperature to improve reaction kinetics. Reduced equilibrium conversion of the WGS reaction at high temperatures is overcome by product H{sub 2} removal via the membrane. This project involves fundamental research and development of novel cerium oxide-based catalysts for the water-gas-shift reaction and the integration of these catalysts with Pd-alloy H{sub 2}-separation membranes supplying high purity hydrogen for fuel cell use. Conditions matching the requirements of coal gasifier-exit gas streams will be examined in the project. In the first year of the project, we prepared a series of nanostructured Cu- and Fe-containing ceria catalysts by a special gelation/precipitation technique followed by air calcination at 650 C. Each sample was characterized by ICP for elemental composition analysis, BET-N2 desorption for surface area measurement, and by temperature-programmed reduction in H{sub 2} to evaluate catalyst reducibility. Screening WGS tests with catalyst powders were conducted in a flow microreactor at temperatures in the range of 200-550 C. On the basis of both activity and stability of catalysts in simulated coal gas, and in CO{sub 2}-rich gases, a Cu-CeO{sub 2} catalyst formulation was selected for further study in this project. Details from the catalyst development and testing work are given in this report. Also in this report, we present H{sub 2} permeation data collected with unsupported flat membranes of pure Pd and Pd-alloys over a wide temperature window.

  3. Method of generating hydrogen gas from sodium borohydride

    DOEpatents

    Kravitz, Stanley H.; Hecht, Andrew M.; Sylwester, Alan P.; Bell, Nelson S.

    2007-12-11

    A compact solid source of hydrogen gas, where the gas is generated by contacting water with micro-disperse particles of sodium borohydride in the presence of a catalyst, such as cobalt or ruthenium. The micro-disperse particles can have a substantially uniform diameter of 1-10 microns, and preferably about 3-5 microns. Ruthenium or cobalt catalytic nanoparticles can be incorporated in the micro-disperse particles of sodium borohydride, which allows a rapid and complete reaction to occur without the problems associated with caking and scaling of the surface by the reactant product sodium metaborate. A closed loop water management system can be used to recycle wastewater from a PEM fuel cell to supply water for reacting with the micro-disperse particles of sodium borohydride in a compact hydrogen gas generator. Capillary forces can wick water from a water reservoir into a packed bed of micro-disperse fuel particles, eliminating the need for using an active pump.

  4. Mechanisms of transition-metal gettering in silicon

    SciTech Connect

    Myers, S. M.; Seibt, M.; Schroeter, W.

    2000-10-01

    The atomic process, kinetics, and equilibrium thermodynamics underlying the gettering of transition-metal impurities in Si are reviewed. Methods for mathematical modeling of gettering are discussed and illustrated. Needs for further research are considered. (c) 2000 American Institute of Physics.

  5. Selective permeation of hydrogen gas using cellulose nanofibril film.

    PubMed

    Fukuzumi, Hayaka; Fujisawa, Shuji; Saito, Tsuguyuki; Isogai, Akira

    2013-05-13

    Biobased membranes that can selectively permeate hydrogen gas have been developed from aqueous dispersions of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibrils (TOCN) prepared from wood cellulose: TOCN-coated plastic films and self-standing TOCN films. Compared with TOCNs with sodium, lithium, potassium, and cesium carboxylate groups, TOCN with free carboxyl groups (TOCN-COOH) had much high and selective H2 gas permeation performance. Because permeabilities of H2, N2, O2, and CO2 gases through the membranes primarily depended on their kinetic diameters, the gas permeation behavior of the various TOCNs can be explained in terms of a diffusion mechanism. Thus, the selective H2 gas permeability for TOCN-COOH was probably due to a larger average size in free volume holes present between nanofibrils in the layer and film than those of other TOCNs with metal carboxylate groups. The obtained results indicate that TOCN-COOH membranes are applicable as biobased H2 gas separation membranes in fuel cell electric power generation systems.

  6. Energy degradation of fast electrons in hydrogen gas

    NASA Technical Reports Server (NTRS)

    Xu, Yueming; Mccray, Richard

    1991-01-01

    An equation is derived for calculating the energy distribution of fast electrons in a partially ionized gas and a method is provided to solve for the electron degradation spectrum and the energy deposition in different forms (ionization, excitation, or heating). As an example, the energy degradation of fast electrons in a gas of pure hydrogen is calculated, considering excitations to the lowest 10 atomic levels. The Bethe approximation and the continuous slowing-down approximation are discussed and it is concluded that these approximations are accurate to the order of 20 percent for electrons with initial energy of greater than about keV. The method and results can be used to determine heating, excitations, and ionizations by high-energy photoelectrons or cosmic-ray particles in various astrophysical circumstances, such as the interstellar medium, supernova envelopes, and QSO emission-line clouds.

  7. Determination of anabolic steroids with gas chromatography-ion trap mass spectrometry using hydrogen as carrier gas.

    PubMed

    Impens, S; De Wasch, K; De Brabander, H

    2001-01-01

    Helium is considered to be the ideal carrier gas for gas chromatography/mass spectrometry (GC/MS) in general, and for use with an ion trap in particular. Helium is an inert gas, can be used without special precautions for security and, moreover, it is needed as a damping gas in the trap. A disadvantage of helium is the high viscosity resulting in long GC run times. In this work hydrogen was tested as an alternative carrier gas for GC in performing GC/MS analyses. A hydrogen generator was used as a safe source of hydrogen gas. It is demonstrated that hydrogen can be used as a carrier gas for the gas chromatograph in combination with helium as make-up gas for the trap. The analysis time was thus shortened and the chromatographic performance was optimized. Although hydrogen has proven useful as a carrier gas in gas chromatography coupled to standard detectors such as ECD or FID, its use is not mentioned extensively in the literature concerning gas chromatography-ion trap mass spectrometry. However, it is worth considering as a possibility because of its chromatographic advantages and its advantageous price when using a hydrogen generator.

  8. Buffer Gas Experiments in Mercury (Hg+) Ion Clock

    NASA Technical Reports Server (NTRS)

    Chung, Sang K.; Prestage, John D.; Tjoelker, Robert L.; Maleki, Lute

    2004-01-01

    We describe the results of the frequency shifts measured from various buffer gases that might be used as a buffer gas to increase the loading efficiency and cooling of ions trapped in a small mercury ion clock. The small mass, volume and power requirement of space clock precludes the use of turbo pumps. Hence, a hermetically sealed vacuum system, incorporating a suitable getter material with a fixed amount of inert buffer gas may be a practical alternative to the groundbased system. The collision shifts of 40,507,347.996xx Hz clock transition for helium, neon and argon buffer gases were measured in the ambient earth magnetic field. In addition to the above non-getterable inert gases we also measured the frequency shifts due to getterable, molecular hydrogen and nitrogen gases which may be used as buffer gases when incorporated with a miniature ion pump. We also examined the frequency shift due to the low methane gas partial pressure in a fixed higher pressure neon buffer gas environment. Methane gas interacted with mercury ions in a peculiar way as to preserve the ion number but to relax the population difference in the two hyperfine clock states and thereby reducing the clock resonance signal. The same population relaxation was also observed for other molecular buffer gases (N H,) but at much reduced rate.

  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. Gas phase hydrogen permeation in alpha titanium and carbon steels

    NASA Technical Reports Server (NTRS)

    Johnson, D. L.; Shah, K. K.; Reeves, B. H.; Gadgeel, V. L.

    1980-01-01

    Commercially pure titanium and heats of Armco ingot iron and steels containing from 0.008-1.23 w/oC were annealed or normalized and machined into hollow cylinders. Coefficients of diffusion for alpha-Ti and alpha-Fe were determined by the lag-time technique. Steady state permeation experiments yield first power pressure dependence for alpha-Ti and Sievert's law square root dependence for Armco iron and carbon steels. As in the case of diffusion, permeation data confirm that alpha-titanium is subject to at least partial phase boundary reaction control while the steels are purely diffusion controlled. The permeation rate in steels also decreases as the carbon content increases. As a consequence of Sievert's law, the computed hydrogen solubility decreases as the carbon content increases. This decreases in explained in terms of hydrogen trapping at carbide interfaces. Oxidizing and nitriding the surfaces of alpha-titanium membranes result in a decrease in the permeation rate for such treatment on the gas inlet surfaces but resulted in a slight increase in the rate for such treatment on the gas outlet surfaces. This is explained in terms of a discontinuous TiH2 layer.

  12. Overview of Two Hydrogen Energy Storage Studies: Wind Hydrogen in California and Blending in Natural Gas Pipelines (Presentation)

    SciTech Connect

    Melaina, M. W.

    2013-05-01

    This presentation provides an overview of two NREL energy storage studies: Wind Hydrogen in California: Case Study and Blending Hydrogen Into Natural Gas Pipeline Networks: A Review of Key Issues. The presentation summarizes key issues, major model input assumptions, and results.

  13. Star Formation as a Function of Neutral Hydrogen Gas Density in Local Group Galaxies

    NASA Astrophysics Data System (ADS)

    Carlson, Erika K.; Madore, Barry F.; Freedman, Wendy L.

    2016-06-01

    We present a study of the efficiency and timescales of star formation as a function of local neutral hydrogen gas density in four Local Group galaxies: M33, NGC 6822, the LMC, and the SMC. In this work, we conceptualize the process of star formation as a cycle of two major phases - (1) a gas dynamics phase in which neutral hydrogen gas coalesces into clouds, and (2) a stellar phase in which stars have formed and interrupt further gas coalescence during their active lifetimes. By examining the spatial distribution and number densities of stars on maps of neutral hydrogen, we estimate the timescale of the gas coalescence phase relative to the timescale of the stellar phase and infer an efficiency of star formation as a function of neutral hydrogen gas density. From these timescales and efficiencies, we will calculate star formation rates as a function of neutral hydrogen gas density in these galaxies.

  14. Effet getter dans des plaquettes de silicium multicristallin par diffusion de phosphore

    NASA Astrophysics Data System (ADS)

    Perichaud, I.; Martinuzzi, S.

    1992-03-01

    The external gettering effect by phosphorus diffusion is used to improve the electrical properties of multicrystalline silicon wafers. After diffusion at 900 °C for 4 h it was found that the effective diffusion lengths L_n of minority carriers achieve or overpass the thickness of the wafers. After diffusion at 850 °C for 4 h the improvements are less marked and hydrogenation is needed to obtain the same increase of L_n. SIMS analysis indicates that the gettered impurities are essentially iron, copper and nickel. Some restricted regions of the wafers are only poorly improved. It was found after chemical etching that these regions contain a high density of subgrain boundaries. The mechanism of the gettering effect used in this work is proposed, taking in account dissolved impurities in the grains and impurities segregated by dislocations. The additivity of the hydrogenation effect might be understood by the neutralisation of the recombination centers related to oxygen atoms segregated by the dislocations. L'effet getter externe par diffusion de phosphore est utilisé pour améliorer les propriétés électriques de plaquettes de silicium multicristallin. Après 4h à 900°C les longueurs de diffusion des porteurs minoritaires atteignent ou dépassent l'épaisseur des plaquettes. Après 4h à 850°C, les augmentations sont moins spectaculaires et une hydrogénation du matériau est nécessaire pour obtenir un résultat comparable au précédent. Les analyses SIMS indiquent que les impuretés extraites sont surtout du fer, du cuivre et du nickel. Certaines régions du matériau, d'extension limitée, sont toutefois peu améliorées. Elles sont caractérisées par la présence d'un réseau très dense de sous-joints. Une interprétation du mécanisme de l'effet getter observé est proposée faisant intervenir les impuretés métalliques dissoutes et celles ségrégées par les dislocations. L'additivité de l'action de l'hydrogène s'expliquerait par la neutralisation

  15. Selective hydrogen gas sensor using CuFe2O4 nanoparticle based thin film

    NASA Astrophysics Data System (ADS)

    Haija, Mohammad Abu; Ayesh, Ahmad I.; Ahmed, Sadiqa; Katsiotis, Marios S.

    2016-04-01

    Hydrogen gas sensors based on CuFe2O4 nanoparticle thin films are presented in this work. Each gas sensor was prepared by depositing CuFe2O4 thin film on a glass substrate by dc sputtering inside a high vacuum chamber. Argon inert gas was used to sputter the material from a composite sputtering target. Interdigitated metal electrodes were deposited on top of the thin films by thermal evaporation and shadow masking. The produced sensors were tested against hydrogen, hydrogen sulfide, and ethylene gases where they were found to be selective for hydrogen. The sensitivity of the produced sensors was maximum for hydrogen gas at 50 °C. In addition, the produced sensors exhibit linear response signal for hydrogen gas with concentrations up to 5%. Those sensors have potential to be used for industrial applications because of their low power requirement, functionality at low temperatures, and low production cost.

  16. Protective Effects of Hydrogen Gas on Experimental Acute Pancreatitis

    PubMed Central

    Zhou, Hao-xin; Han, Bing; Hou, Li-Min; An, Ting-Ting; Jia, Guang; Cheng, Zhuo-Xin; Ma, Yong; Zhou, Yi-Nan; Kong, Rui; Wang, Shuang-Jia; Wang, Yong-Wei; Sun, Xue-Jun; Pan, Shang-Ha; Sun, Bei

    2016-01-01

    Acute pancreatitis (AP) is an inflammatory disease mediated by damage to acinar cells and pancreatic inflammation. In patients with AP, subsequent systemic inflammatory responses and multiple organs dysfunction commonly occur. Interactions between cytokines and oxidative stress greatly contribute to the amplification of uncontrolled inflammatory responses. Molecular hydrogen (H2) is a potent free radical scavenger that not only ameliorates oxidative stress but also lowers cytokine levels. The aim of the present study was to investigate the protective effects of H2 gas on AP both in vitro and in vivo. For the in vitro assessment, AR42J cells were treated with cerulein and then incubated in H2-rich or normal medium for 24 h, and for the in vivo experiment, AP was induced through a retrograde infusion of 5% sodium taurocholate into the pancreatobiliary duct (0.1 mL/100 g body weight). Wistar rats were treated with inhaled air or 2% H2 gas and sacrificed 12 h following the induction of pancreatitis. Specimens were collected and processed to measure the amylase and lipase activity levels; the myeloperoxidase activity and production levels; the cytokine mRNA expression levels; the 8-hydroxydeoxyguanosine, malondialdehyde, and glutathione levels; and the cell survival rate. Histological examinations and immunohistochemical analyses were then conducted. The results revealed significant reductions in inflammation and oxidative stress both in vitro and in vivo. Furthermore, the beneficial effects of H2 gas were associated with reductions in AR42J cell and pancreatic tissue damage. In conclusion, our results suggest that H2 gas is capable of ameliorating damage to the pancreas and AR42J cells and that H2 exerts protective effects both in vitro and in vivo on subjects with AP. Thus, the results obtained indicate that this gas may represent a novel therapy agent in the management of AP. PMID:27115738

  17. WATER-GAS SHIFT WITH INTEGRATED HYDROGEN SEPARATION PROCESS

    SciTech Connect

    Maria Flytzani-Stephanopoulos; Xiaomei Qi; Scott Kronewitter

    2004-02-01

    This project involved fundamental research and development of novel cerium oxide-based catalysts for the water-gas-shift reaction and the integration of these catalysts with Pd-alloy H{sub 2} -separation membranes supplying high purity hydrogen for fuel cell use. Conditions matching the requirements of coal gasifier-exit gas streams were examined in the project. Cu-cerium oxide was identified as the most promising high-temperature water-gas shift catalyst for integration with H{sub 2}-selective membranes. Formulations containing iron oxide were found to deactivate in the presence of CO{sub 2}. Cu-containing ceria catalysts, on the other hand, showed high stability in CO{sub 2}-rich gases. This type gas will be present over much of the catalyst, as the membrane removes the hydrogen produced from the shift reaction. The high-temperature shift catalyst composition was optimized by proper selection of dopant type and amount in ceria. The formulation 10at%Cu-Ce(30at%La)O{sub x} showed the best performance, and was selected for further kinetic studies. WGS reaction rates were measured in a simulated coal-gas mixture. The apparent activation energy, measured over aged catalysts, was equal to 70.2 kJ/mol. Reaction orders in CO, H{sub 2}O, CO{sub 2} and H{sub 2} were found to be 0.8, 0.2, -0.3, and -0.3, respectively. This shows that H{sub 2}O has very little effect on the reaction rate, and that both CO{sub 2} and H{sub 2} weakly inhibit the reaction. Good stability of catalyst performance was found in 40-hr long tests. A flat (38 cm{sup 2}) Pd-Cu alloy membrane reactor was used with the catalyst washcoated on oxidized aluminum screens close coupled with the membrane. To achieve higher loadings, catalyst granules were layered on the membrane itself to test the combined HTS activity/ H{sub 2} -separation efficiency of the composite. Simulated coal gas mixtures were used and the effect of membrane on the conversion of CO over the catalyst was evidenced at high space

  18. Lifetime prediction in vacuum packaged MEMS provided with integrated getter film

    NASA Astrophysics Data System (ADS)

    Siviero, Fabrizio; Bonucci, Antonio; Conte, Andrea; Moraja, Marco; Gigan, Olivier; Thomas, Isabelle

    2012-06-01

    Thin-film getter integration is one of the key technologies enabling the development of a wide class of MEMS devices, such as IR microbolometers and inertial sensors, where stringent vacuum requirements must be satisfied to achieve the desired performances and preserve them for the entire lifetime. Despite its importance, the question about lifetime prediction is still very difficult to answer in a reliable way. Here we present an experimental approach to the evaluation of lifetime, based on an accelerated life test performed varying both the storage conditions and the getter area. A test vehicle based on a resonator device was used. The hermeticity was evaluated by means of specific leak testing, while MEMS behavior during the ageing test was studied monitoring device functional parameters and by residual gas analysis (RGA). Unexpected results were observed leading to the discovery that methane is pumped by the getter below 100°C. These results served as the inputs of a suitable model allowing extrapolating the device lifetime in operating? conditions, and pointed out that RGA is an essential tool to correctly interpret the aging tests.

  19. Microsensor measurements of hydrogen gas dynamics in cyanobacterial microbial mats.

    PubMed

    Nielsen, Michael; Revsbech, Niels P; Kühl, Michael

    2015-01-01

    We used a novel amperometric microsensor for measuring hydrogen gas production and consumption at high spatio-temporal resolution in cyanobacterial biofilms and mats dominated by non-heterocystous filamentous cyanobacteria (Microcoleus chtonoplastes and Oscillatoria sp.). The new microsensor is based on the use of an organic electrolyte and a stable internal reference system and can be equipped with a chemical sulfide trap in the measuring tip; it exhibits very stable and sulfide-insensitive measuring signals and a high sensitivity (1.5-5 pA per μmol L(-1) H2). Hydrogen gas measurements were done in combination with microsensor measurements of scalar irradiance, O2, pH, and H2S and showed a pronounced H2 accumulation (of up to 8-10% H2 saturation) within the upper mm of cyanobacterial mats after onset of darkness and O2 depletion. The peak concentration of H2 increased with the irradiance level prior to darkening. After an initial build-up over the first 1-2 h in darkness, H2 was depleted over several hours due to efflux to the overlaying water, and due to biogeochemical processes in the uppermost oxic layers and the anoxic layers of the mats. Depletion could be prevented by addition of molybdate pointing to sulfate reduction as a major sink for H2. Immediately after onset of illumination, a short burst of presumably photo-produced H2 due to direct biophotolysis was observed in the illuminated but anoxic mat layers. As soon as O2 from photosynthesis started to accumulate, the H2 was consumed rapidly and production ceased. Our data give detailed insights into the microscale distribution and dynamics of H2 in cyanobacterial biofilms and mats, and further support that cyanobacterial H2 production can play a significant role in fueling anaerobic processes like e.g., sulfate reduction or anoxygenic photosynthesis in microbial mats.

  20. Microsensor measurements of hydrogen gas dynamics in cyanobacterial microbial mats

    PubMed Central

    Nielsen, Michael; Revsbech, Niels P.; Kühl, Michael

    2015-01-01

    We used a novel amperometric microsensor for measuring hydrogen gas production and consumption at high spatio-temporal resolution in cyanobacterial biofilms and mats dominated by non-heterocystous filamentous cyanobacteria (Microcoleus chtonoplastes and Oscillatoria sp.). The new microsensor is based on the use of an organic electrolyte and a stable internal reference system and can be equipped with a chemical sulfide trap in the measuring tip; it exhibits very stable and sulfide-insensitive measuring signals and a high sensitivity (1.5–5 pA per μmol L-1 H2). Hydrogen gas measurements were done in combination with microsensor measurements of scalar irradiance, O2, pH, and H2S and showed a pronounced H2 accumulation (of up to 8–10% H2 saturation) within the upper mm of cyanobacterial mats after onset of darkness and O2 depletion. The peak concentration of H2 increased with the irradiance level prior to darkening. After an initial build-up over the first 1–2 h in darkness, H2 was depleted over several hours due to efflux to the overlaying water, and due to biogeochemical processes in the uppermost oxic layers and the anoxic layers of the mats. Depletion could be prevented by addition of molybdate pointing to sulfate reduction as a major sink for H2. Immediately after onset of illumination, a short burst of presumably photo-produced H2 due to direct biophotolysis was observed in the illuminated but anoxic mat layers. As soon as O2 from photosynthesis started to accumulate, the H2 was consumed rapidly and production ceased. Our data give detailed insights into the microscale distribution and dynamics of H2 in cyanobacterial biofilms and mats, and further support that cyanobacterial H2 production can play a significant role in fueling anaerobic processes like e.g., sulfate reduction or anoxygenic photosynthesis in microbial mats. PMID:26257714

  1. Argon recovery from hydrogen depleted ammonia plant purge gas using a HARP Plant

    SciTech Connect

    Krishnamurthy, R.; Lerner, S.L.; Maclean, D.L.

    1987-01-01

    A number of ammonia plants employ membranes or cryogenic hydrogen recovery units to separate hydrogen contained in the purge gas for recycle to the ammonia synthesis loop. The resulting hydrogen depleted purge gas, which is usually used for fuel, is an attractive source of argon. This paper presents the novel features of a process which employs a combination of pressure swing adsorption (PSA) and cryogenic technology to separate the argon from this hydrogen depleted purge gas stream. This new proprietary Hybrid Argon Recovery Progress (HARP) plant is an effective alternative to a conventional all-cryogenic plant.

  2. Numerical simulation of high pressure release and dispersion of hydrogen into air with real gas model

    NASA Astrophysics Data System (ADS)

    Khaksarfard, R.; Kameshki, M. R.; Paraschivoiu, M.

    2010-06-01

    Hydrogen is a renewable and clean source of energy, and it is a good replacement for the current fossil fuels. Nevertheless, hydrogen should be stored in high-pressure reservoirs to have sufficient energy. An in-house code is developed to numerically simulate the release of hydrogen from a high-pressure tank into ambient air with more accuracy. Real gas models are used to simulate the flow since high-pressure hydrogen deviates from ideal gas law. Beattie-Bridgeman and Abel Noble equations are applied as real gas equation of state. A transport equation is added to the code to calculate the concentration of the hydrogen-air mixture after release. The uniqueness of the code is to simulate hydrogen in air release with the real gas model. Initial tank pressures of up to 70 MPa are simulated.

  3. Effect of hydrogen in an argon GTAW shielding gas: Arc characteristics and bead morphology

    SciTech Connect

    Onsoeien, M.; Olson, D.L.; Liu, S. . Center for Welding and Joining Research); Peters, R. )

    1995-01-01

    The influence of hydrogen additions to an argon shielding gas on the heat input and weld bead morphology was investigated using the gas tungsten arc welding process. Variations in weld bead size and shape with hydrogen additions were related to changes in the ability of the arc to generate heat and not to generate perturbations in the weld pool caused by Marangoni fluid flow.

  4. Study of Hydrogen Recovery Systems for Gas Vented While Refueling Liquid-Hydrogen Fueled Aircraft

    NASA Technical Reports Server (NTRS)

    Baker, C. R.

    1979-01-01

    Methods of capturing and reliquefying the cold hydrogen vapor produced during the fueling of aircraft designed to utilize liquid hydrogen fuel were investigated. An assessment of the most practical, economic, and energy efficient of the hydrogen recovery methods is provided.

  5. Upgrade to the Cryogenic Hydrogen Gas Target Monitoring System

    NASA Astrophysics Data System (ADS)

    Slater, Michael; Tribble, Robert

    2013-10-01

    The cryogenic hydrogen gas target at Texas A&M is a vital component for creating a secondary radioactive beam that is then used in experiments in the Momentum Achromat Recoil Spectrometer (MARS). A stable beam from the K500 superconducting cyclotron enters the gas cell and some incident particles are transmuted by a nuclear reaction into a radioactive beam, which are separated from the primary beam and used in MARS experiments. The pressure in the target chamber is monitored so that a predictable isotope production rate can be assured. A ``black box'' received the analog pressure data and sent RS232 serial data through an outdated serial connection to an outdated Visual Basic 6 (VB6) program, which plotted the chamber pressure continuously. The black box has been upgraded to an Arduino UNO microcontroller [Atmel Inc.], which can receive the pressure data and output via USB to a computer. It has been programmed to also accept temperature data for future upgrade. A new computer program, with updated capabilities, has been written in Python. The software can send email alerts, create audible alarms through the Arduino, and plot pressure and temperature. The program has been designed to better fit the needs of the users. Funded by DOE and NSF-REU Program.

  6. Hydrodesulphurization of Light Gas Oil using hydrogen from the Water Gas Shift Reaction

    NASA Astrophysics Data System (ADS)

    Alghamdi, Abdulaziz

    2009-12-01

    The production of clean fuel faces the challenges of high production cost and complying with stricter environmental regulations. In this research, the ability of using a novel technology of upgrading heavy oil to treat Light Gas Oil (LGO) will be investigated. The target of this project is to produce cleaner transportation fuel with much lower cost of production. Recently, a novel process for upgrading of heavy oil has been developed at University of Waterloo. It is combining the two essential processes in bitumen upgrading; emulsion breaking and hydroprocessing into one process. The water in the emulsion is used to generate in situ hydrogen from the Water Gas Shift Reaction (WGSR). This hydrogen can be used for the hydrogenation and hydrotreating reaction which includes sulfur removal instead of the expensive molecular hydrogen. This process can be carried out for the upgrading of the bitumen emulsion which would improve its quality. In this study, the hydrodesulphurization (HDS) of LGO was conducted using in situ hydrogen produced via the Water Gas Shift Reaction (WGSR). The main objective of this experimental study is to evaluate the possibility of producing clean LGO over dispersed molybdenum sulphide catalyst and to evaluate the effect of different promoters and syn-gas on the activity of the dispersed Mo catalyst. Experiments were carried out in a 300 ml Autoclave batch reactor under 600 psi (initially) at 391°C for 1 to 3 hours and different amounts of water. After the hydrotreating reaction, the gas samples were collected and the conversion of carbon monoxide to hydrogen via WGSR was determined using a refinery gas analyzer. The sulphur content in liquid sample was analyzed via X-Ray Fluorescence. Experimental results showed that using more water will enhance WGSR but at the same time inhibits the HDS reaction. It was also shown that the amount of sulfur removed depends on the reaction time. The plan is to investigate the effect of synthesis gas (syngas

  7. Measurements of laminar burning velocities for natural gas-hydrogen-air mixtures

    SciTech Connect

    Huang, Zuohua; Zhang, Yong; Zeng, Ke; Liu, Bing; Wang, Qian; Jiang, Deming

    2006-07-15

    Laminar flame characteristics of natural gas-hydrogen-air flames were studied in a constant-volume bomb at normal temperature and pressure. Laminar burning velocities and Markstein lengths were obtained at various ratios of hydrogen to natural gas (volume fraction from 0 to 100%) and equivalence ratios (f from 0.6 to 1.4). The influence of stretch rate on flame was also analyzed. The results show that, for lean mixture combustion, the flame radius increases with time but the increasing rate decreases with flame expansion for natural gas and for mixtures with low hydrogen fractions, while at high hydrogen fractions, there exists a linear correlation between flame radius and time. For rich mixture combustion, the flame radius shows a slowly increasing rate at early stages of flame propagation and a quickly increasing rate at late stages of flame propagation for natural gas and for mixtures with low hydrogen fractions, and there also exists a linear correlation between flame radius and time for mixtures with high hydrogen fractions. Combustion at stoichiometric mixture demonstrates the linear relationship between flame radius and time for natural gas-air, hydrogen-air, and natural gas-hydrogen-air flames. Laminar burning velocities increase exponentially with the increase of hydrogen fraction in mixtures, while the Markstein length decreases and flame instability increases with the increase of hydrogen fractions in mixture. For a fixed hydrogen fraction, the Markstein number shows an increase and flame stability increases with the increase of equivalence ratios. Based on the experimental data, a formula for calculating the laminar burning velocities of natural gas-hydrogen-air flames is proposed. (author)

  8. Hydrogen gas sensor based on palladium and yttrium alloy ultrathin film.

    PubMed

    Yi, Liu; You-Ping, Chen; Han, Song; Gang, Zhang

    2012-12-01

    Compared with the other hydrogen sensors, optical fiber hydrogen sensors based on thin films exhibits inherent safety, small volume, immunity to electromagnetic interference, and distributed remote sensing capability, but slower response characteristics. To improve response and recovery rate of the sensors, a novel reflection-type optical fiber hydrogen gas sensor with a 10 nm palladium and yttrium alloy thin film is fabricated. The alloy thin film shows a good hydrogen sensing property for hydrogen-containing atmosphere and a complete restorability for dry air at room temperature. The variation in response value of the sensor linearly increases with increased natural logarithm of hydrogen concentration (ln[H(2)]). The shortest response time and recovery response time to 4% hydrogen are 6 and 8 s, respectively. The hydrogen sensors based on Pd(0.91)Y(0.09) alloy ultrathin film have potential applications in hydrogen detection and measurement.

  9. Hydrogen gas sensor based on palladium and yttrium alloy ultrathin film

    NASA Astrophysics Data System (ADS)

    Yi, Liu; You-ping, Chen; Han, Song; Gang, Zhang

    2012-12-01

    Compared with the other hydrogen sensors, optical fiber hydrogen sensors based on thin films exhibits inherent safety, small volume, immunity to electromagnetic interference, and distributed remote sensing capability, but slower response characteristics. To improve response and recovery rate of the sensors, a novel reflection-type optical fiber hydrogen gas sensor with a 10 nm palladium and yttrium alloy thin film is fabricated. The alloy thin film shows a good hydrogen sensing property for hydrogen-containing atmosphere and a complete restorability for dry air at room temperature. The variation in response value of the sensor linearly increases with increased natural logarithm of hydrogen concentration (ln[H2]). The shortest response time and recovery response time to 4% hydrogen are 6 and 8 s, respectively. The hydrogen sensors based on Pd0.91Y0.09 alloy ultrathin film have potential applications in hydrogen detection and measurement.

  10. Introducing porous silicon as a sacrificial material to obtain cavities in substrate of SOI wafers and a getter material for MEMS devices

    NASA Astrophysics Data System (ADS)

    Mohammad, Wajihuddin

    Microelectromechanical system (MEMS) resonators have been a subject of research for more than four decades. The reason is the huge potential they possess for frequency applications. The use of a MEMS resonator as the timing element has an experimental history and huge progress has been made in this direction. Vacuum encapsulated MEMS resonators are required for high precision frequency control. Hence, a device with a high quality factor and durability is needed. In this effort, a new process for producing a cavity in the substrate of Silicon on insulator (SOI) MEMS devices and augmenting it with a getter using porous silicon is developed. The process involves a mask-less, self-aligned cost effective electrochemical etching process. A 10 mum cavity is introduced in the substrate of SOI dies. This helps in increasing the packaging volume of the SOI resonators along with mitigating the viscous damping effects. The stiction problem in MEMS devices is effectively eliminated and millimeter long slender MEMS structures do not get stuck to the substrate. It also helps in reducing the parasitic capacitance between the device side and the substrate. The porous silicon getter is introduced as a getter material for vacuum encapsulated MEMS devices. This getter needs no external mask and is self-aligned. It requires no external heat or additional materials to operate. The highly reactive porous silicon can readily react with the oxygen gas and form an oxide layer that can trap other gas molecules. This helps in maintaining low pressures in the cavity of the bonded MEMS resonators. A tuning fork resonator with a resonant frequency of 245 kHz was used to realize the benefits of the cavity and the getter. It was observed that the unpackaged device with the cavity in the substrate showed two times better quality factor at different pressures, than the device with no cavity. In order to understand the benefits of porous silicon as a getter, the MEMS devices (one with only a cavity

  11. APPARATUS AND METHOD FOR TREATING POLLUTANTS IN A GAS USING HYDROGEN PEROXIDE AND UV LIGHT

    NASA Technical Reports Server (NTRS)

    Cooper, Charles David (Inventor); Clauseu, christian Anthony (Inventor)

    2005-01-01

    An apparatus for treating pollutants in a gas may include a source of hydrogen peroxide, and a treatment injector for creating and injecting dissociated hydrogen peroxide into the flow of gas. The treatment injector may further include an injector housing having an inlet, an outlet, and a hollow interior extending there between. The inlet may be connected in fluid communication with the source of hydrogen peroxide so that hydrogen peroxide flows through the hollow interior and toward the outlet. At least one ultraviolet (UV) lamp may be positioned within the hollow interior of the injector housing. The at least one UV lamp may dissociate the hydrogen peroxide flowing through the tube. The dissociated hydrogen peroxide may be injected into the flow of gas from the outlet for treating pollutants, such as nitrogen oxides.

  12. Apparatus and method for treating pollutants in a gas using hydrogen peroxide and UV light

    NASA Technical Reports Server (NTRS)

    Cooper, Charles David (Inventor); Clausen, Christian Anthony (Inventor)

    2005-01-01

    An apparatus for treating pollutants in a gas may include a source of hydrogen peroxide, and a treatment injector for creating and injecting dissociated hydrogen peroxide into the flow of gas. The treatment injector may further include an injector housing having an inlet, an outlet, and a hollow interior extending therebetween. The inlet may be connected in fluid communication with the source of hydrogen peroxide so that hydrogen peroxide flows through the hollow interior and toward the outlet. At least one ultraviolet (UV) lamp may be positioned within the hollow interior of the injector housing. The at least one UV lamp may dissociate the hydrogen peroxide flowing through the tube. The dissociated hydrogen peroxide may be injected into the flow of gas from the outlet for treating pollutants, such as nitrogen oxides.

  13. Silicon carbide-based hydrogen gas sensors for high-temperature applications.

    PubMed

    Kim, Seongjeen; Choi, Jehoon; Jung, Minsoo; Joo, Sungjae; Kim, Sangchoel

    2013-01-01

    We investigated SiC-based hydrogen gas sensors with metal-insulator-semiconductor (MIS) structure for high temperature process monitoring and leak detection applications in fields such as the automotive, chemical and petroleum industries. In this work, a thin tantalum oxide (Ta2O5) layer was exploited with the purpose of sensitivity improvement, because tantalum oxide has good stability at high temperature with high permeability for hydrogen gas. Silicon carbide (SiC) was used as a substrate for high-temperature applications. We fabricated Pd/Ta2O5/SiC-based hydrogen gas sensors, and the dependence of their I-V characteristics and capacitance response properties on hydrogen concentrations were analyzed in the temperature range from room temperature to 500 °C. According to the results, our sensor shows promising performance for hydrogen gas detection at high temperatures. PMID:24113685

  14. Getters for Tc and I Removal from Liquid Waste

    NASA Astrophysics Data System (ADS)

    Qafoku, N. P.; Asmussen, M.; Lawter, A.; Neeway, J.; Smith, G.

    2015-12-01

    A cementitious waste form, Cast Stone, is being evaluated as a possible supplemental waste form for the low activity waste (LAW) at the Hanford Site, which contains significant amounts of radioactive 99Tc and 129I, as part of the tank waste cleanup mission. To improve the retention of Tc and/or I in Cast Stone, materials with a high affinity for Tc and/or I, termed "getters," can be added to decrease the rate of contaminant release and diffusivity, and improve Cast Stone performance. A series of kinetic batch sorption experiments was performed to determine the effectiveness of the getter materials. Several Tc getters [blast furnace slag, Sn (II) apatite, SnCl2, nanoporous Sn phosphate, KMS-2 (a potassium-metal-sulfide), and Sn(II) hydroxyapatite] and I getters [layered Bi hydroxide, natural argentite mineral, synthetic argentite, Ag-impregnated carbon, and Ag-exchanged zeolite] were tested in different solution media, 18.2 MΩ DI H2O and a caustic LAW waste simulant containing 6.5 M Na or 7.8 M Na. The experiments were conducted at room temperature in the presence or absence of air. Results indicated that most Tc getters (with the exception of KMS-2) performed better in the DI H2O solution than in the 6.5 and 7.8 M Na LAW simulant. In addition, Tc sequestration may be affected by the presence of other redox sensitive elements that were present in the LAW simulant, such as Cr. The Tc getter materials have been examined through various solid-state characterization techniques such as XRD, SEM/EDS, XANES and EXAFS which provided evidence for plausible mechanisms of aqueous Tc removal. The results indicated that the Tc precipitates differ depending on the getter material and that Tc(VII) is reduced to Tc(IV) in most of the getters but to a differing extents. For the I getters, Ag-exchanged zeolite and synthetic argentite were the most effective ones. The other I getters showed limited effectiveness for sorbing I under the high ionic strength and caustic

  15. Molecular wake shield gas analyzer

    NASA Technical Reports Server (NTRS)

    Hoffman, J. H.

    1980-01-01

    Techniques for measuring and characterizing the ultrahigh vacuum in the wake of an orbiting spacecraft are studied. A high sensitivity mass spectrometer that contains a double mass analyzer consisting of an open source miniature magnetic sector field neutral gas analyzer and an identical ion analyzer is proposed. These are configured to detect and identify gas and ion species of hydrogen, helium, nitrogen, oxygen, nitric oxide, and carbon dioxide and any other gas or ion species in the 1 to 46 amu mass range. This range covers the normal atmospheric constituents. The sensitivity of the instrument is sufficient to measure ambient gases and ion with a particle density of the order of one per cc. A chemical pump, or getter, is mounted near the entrance aperture of the neutral gas analyzer which integrates the absorption of ambient gases for a selectable period of time for subsequent release and analysis. The sensitivity is realizable for all but rare gases using this technique.

  16. Refractory two-dimensional hole gas on hydrogenated diamond surface

    SciTech Connect

    Hiraiwa, Atsushi; Daicho, Akira; Kurihara, Shinichiro; Yokoyama, Yuki; Kawarada, Hiroshi

    2012-12-15

    Use of two-dimensional hole gas (2DHG), induced on a hydrogenated diamond surface, is a solution to overcoming one of demerits of diamond, i.e., deep energy levels of impurities. This 2DHG is affected by its environment and accordingly needs a passivation film to get a stable device operation especially at high temperature. In response to this requirement, we achieved the high-reliability passivation forming an Al{sub 2}O{sub 3} film on the diamond surface using an atomic-layer-deposition (ALD) method with an H{sub 2}O oxidant at 450 Degree-Sign C. The 2DHG thus protected survived air annealing at 550 Degree-Sign C for an hour, establishing a stable high-temperature operation of 2DHG devices in air. In part, this achievement is based on high stability of C-H bonds up to 870 Degree-Sign C in vacuum and above 450 Degree-Sign C in an H{sub 2}O-containing environment as in the ALD. Chemically, this stability is supported by the fact that both the thermal decomposition of C-H bonds and reaction between C-H bonds and H{sub 2}O are endothermic processes. It makes a stark contrast to the instability of Si-H bonds, which decompose even at room temperature being exposed to atomic hydrogen. In this respect, the diamond 2DHG devices are also promising as power devices expectedly being free from many instability phenomena, such as hot carrier effect and negative-bias temperature instability, associated with Si devices. As to adsorbate, which is the other prerequisite for 2DHG, it desorbed in vacuum below 250 Degree-Sign C, and accordingly some new adsorbates should have adsorbed during the ALD at 450 Degree-Sign C. As a clue to this question, we certainly confirmed that some adsorbates, other than those at room temperature, adsorbed in air above 100 Degree-Sign C and remained at least up to 290 Degree-Sign C. The identification of these adsorbates is open for further investigation.

  17. Zeolite Membrane Reactor for Water Gas Shift Reaction for Hydrogen Production

    SciTech Connect

    Lin, Jerry Y.S.

    2013-01-29

    Gasification of biomass or heavy feedstock to produce hydrogen fuel gas using current technology is costly and energy-intensive. The technology includes water gas shift reaction in two or more reactor stages with inter-cooling to maximize conversion for a given catalyst volume. This project is focused on developing a membrane reactor for efficient conversion of water gas shift reaction to produce a hydrogen stream as a fuel and a carbon dioxide stream suitable for sequestration. The project was focused on synthesizing stable, hydrogen perm-selective MFI zeolite membranes for high temperature hydrogen separation; fabricating tubular MFI zeolite membrane reactor and stable water gas shift catalyst for membrane reactor applications, and identifying experimental conditions for water gas shift reaction in the zeolite membrane reactor that will produce a high purity hydrogen stream. The project has improved understanding of zeolite membrane synthesis, high temperature gas diffusion and separation mechanisms for zeolite membranes, synthesis and properties of sulfur resistant catalysts, fabrication and structure optimization of membrane supports, and fundamentals of coupling reaction with separation in zeolite membrane reactor for water gas shift reaction. Through the fundamental study, the research teams have developed MFI zeolite membranes with good perm-selectivity for hydrogen over carbon dioxide, carbon monoxide and water vapor, and high stability for operation in syngas mixture containing 500 part per million hydrogen sulfide at high temperatures around 500°C. The research teams also developed a sulfur resistant catalyst for water gas shift reaction. Modeling and experimental studies on the zeolite membrane reactor for water gas shift reaction have demonstrated the effective use of the zeolite membrane reactor for production of high purity hydrogen stream.

  18. Modification and testing of an engine and fuel control system for a hydrogen fuelled gas turbine

    NASA Astrophysics Data System (ADS)

    Funke, H. H.-W.; Börner, S.; Hendrick, P.; Recker, E.

    2011-10-01

    The control of pollutant emissions has become more and more important by the development of new gas turbines. The use of hydrogen produced by renewable energy sources could be an alternative. Besides the reduction of NOx emissions emerged during the combustion process, another major question is how a hydrogen fuelled gas turbine including the metering unit can be controlled and operated. This paper presents a first insight in modifications on an Auxiliary Power Unit (APU) GTCP 36300 for using gaseous hydrogen as a gas turbine fuel. For safe operation with hydrogen, the metering of hydrogen has to be fast, precise, and secure. So, the quality of the metering unit's control loop has an important influence on this topic. The paper documents the empiric determination of the proportional integral derivative (PID) control parameters for the metering unit.

  19. FIRST OPERATING RESULTS OF A DYNAMIC GAS BEARING TURBINE IN AN INDUSTRIAL HYDROGEN LIQUEFIER

    SciTech Connect

    Bischoff, S.; Decker, L.

    2010-04-09

    Hydrogen has been brought into focus of industry and public since fossil fuels are depleting and costs are increasing dramatically. Beside these issues new high-tech processes in the industry are in need for hydrogen at ultra pure quality. To achieve these requirements and for efficient transportation, hydrogen is liquefied in industrial plants. Linde Gas has commissioned a new 5.5 TPD Hydrogen liquefier in Leuna, Germany, which has been engineered and supplied by Linde Kryotechnik. One of the four expansion turbines installed in the liquefaction process is equipped with dynamic gas bearings. Several design features and operational characteristics of this application will be discussed. The presentation will include results of efficiency and operational reliability that have been determined from performance tests. The advantages of the Linde dynamic gas bearing turbine for future use in hydrogen liquefaction plants will be shown.

  20. Technetium and Iodine Getters to Improve Cast Stone Performance

    SciTech Connect

    Qafoku, Nikolla; Neeway, James J.; Lawter, Amanda R.; Levitskaia, Tatiana G.; Serne, R. Jeffrey; Westsik, Joseph H.; Snyder, Michelle MV

    2014-07-01

    To determine the effectiveness of the various getter materials prior to their solidification in Cast Stone, a series of batch sorption experiments was performed at Pacific Northwest National Laboratory. To quantify the effectiveness of the removal of Tc(VII) and I(I) from solution by getters, the distribution coefficient, Kd (mL/g), was calculated. Testing involved placing getter material in contact with spiked waste solutions at a 1:100 solid-to-solution ratio for periods up to 45 days with periodic solution sampling. One Tc getter was also tested at a 1:10 solid-to-solution ratio. Two different solution media, 18.2 MΩ deionized water (DI H2O) and a 7.8 M Na LAW simulant, were used in the batch sorption tests. Each test was conducted at room temperature in an anoxic chamber containing N2 with a small amount of H2 (0.7%) to maintain anoxic conditions. Each getter-solution combination was run in duplicate. Three Tc- and I-doping concentrations were used separately in aliquots of both the 18.2 MΩ DI H2O and a 7.8 M Na LAW waste simulant. The 1× concentration was developed based on Hanford Tank Waste Operations Simulator (HTWOS) model runs to support the River Protection Project System Plan Revision 6. The other two concentrations were 5× and 10× of the HTWOS values. The Tc and I tests were run separately (i.e., the solutions did not contain both solutes). Sampling of the solid-solution mixtures occurred nominally after 0.2, 1, 3, 6, 9, 12, 15 days and ~35 to 45 days. Seven getter materials were tested for Tc and five materials were tested for I. The seven Tc getters were blast furnace slag 1 (BFS1) (northwest source), BFS2 (southeast source), Sn(II)-treated apatite, Sn(II) chloride, nano tin phosphate, KMS (a potassium-metal-sulfide), and tin hydroxapatite. The five iodine getters were layered bismuth hydroxide (LBH), argentite mineral, synthetic argentite, silver-treated carbon, and silver-treated zeolite. The Tc Kd values measured from experiments conducted

  1. Technetium and Iodine Getters to Improve Cast Stone Performance

    SciTech Connect

    Qafoku, Nikolla; Neeway, James J.; Lawter, Amanda R.; Levitskaia, Tatiana G.; Serne, R. Jeffrey; Westsik, Joseph H.; Snyder, Michelle MV

    2015-02-19

    To determine the effectiveness of the various getter materials prior to their solidification in Cast Stone, a series of batch sorption experiments was performed at Pacific Northwest National Laboratory. To quantify the effectiveness of the removal of Tc(VII) and I(I) from solution by getters, the distribution coefficient, Kd (mL/g), was calculated. Testing involved placing getter material in contact with spiked waste solutions at a 1:100 solid-to-solution ratio for periods up to 45 days with periodic solution sampling. One Tc getter was also tested at a 1:10 solid-to-solution ratio. Two different solution media, 18.2 MΩ deionized water (DI H2O) and a 7.8 M Na LAW simulant, were used in the batch sorption tests. Each test was conducted at room temperature in an anoxic chamber containing N2 with a small amount of H2 (0.7%) to maintain anoxic conditions. Each getter-solution combination was run in duplicate. Three Tc- and I-doping concentrations were used separately in aliquots of both the 18.2 MΩ DI H2O and a 7.8 M Na LAW waste simulant. The 1× concentration was developed based on Hanford Tank Waste Operations Simulator (HTWOS) model runs to support the River Protection Project System Plan Revision 6. The other two concentrations were 5× and 10× of the HTWOS values. The Tc and I tests were run separately (i.e., the solutions did not contain both solutes). Sampling of the solid-solution mixtures occurred nominally after 0.2, 1, 3, 6, 9, 12, 15 days and ~35 to 45 days. Seven getter materials were tested for Tc and five materials were tested for I. The seven Tc getters were blast furnace slag 1 (BFS1) (northwest source), BFS2 (southeast source), Sn(II)-treated apatite, Sn(II) chloride, nano tin phosphate, KMS (a potassium-metal-sulfide), and tin hydroxapatite. The five iodine getters were layered bismuth hydroxide (LBH), argentite mineral, synthetic argentite, silver-treated carbon, and silver-treated zeolite. The Tc Kd values measured from experiments conducted

  2. Transient getter scheme for the Tokamak Fusion Test Reactor

    SciTech Connect

    Cecchi, J.L.; Cohen, S.A.; Sredniawski, J.J.

    1980-01-01

    The ability of the Tokamak Fusion Test Reactor (TFTR) to attain the largest fusion power gain depends critically on minimizing plasma contamination and controlling the densities of the reacting deuterium and tritium. Experiments on a number of tokamaks have demonstrated that gettering over an appreciable surface area (greater than or equal to 10%) of the vacuum vessel greatly facilitates both of these objectives. One particular problem in implementing a surface pumping system in TFTR, however, is a restriction on the maximum allowable tritium content of the getter. This restriction could require regeneration of the absorbed tritium after as few as 50 machine pulses. We have developed a scheme utilizing SAES Zr/Al getter modules which obviates the need for such frequent interruptions of machine operation by taking advantage of the pulsed operation of TFTR. With the Zr/Al getter at temperatures between 500/sup 0/C to 600/sup 0/C it is possible to achieve a quasi-steady state in the tritium loading where the quantity of tritium desorbed between pulses is equal to the quantity which is absorbed during a pulse. Since frequent thermal cycling is not required, this scheme also reduces the possibility of Zr/Al getter material fatigue.

  3. Hydrogen Gas from Serpentinite, Ophiolites and the Modern Ocean Floor as a Source of Green Energy

    NASA Astrophysics Data System (ADS)

    Coveney, R. M.

    2008-12-01

    Hydrogen gas is emitted by springs associated with serpentinites and extensive carbonate deposits in Oman, The Philippines, the USA and other continental locations. The hydrogen springs contain unusually alkaline fluids with pH values between 11 and 12.5. Other workers have described off-ridge submarine springs with comparably alkaline fluid compositions, serpentinite, abundant free hydrogen gas, and associated carbonate edifices such as Lost City on the Atlantis Massif 15 km west of the Mid-Atlantic Ridge (D.S. Kelley and associates, Science 2005). The association of hydrogen gas with ultramafites is a consistent one that has been attributed to a redox couple involving oxidation of divalent iron to the trivalent state during serpentinization, although other possibilities exist. Some of the hydrogen springs on land are widespread. For example in Oman dozens of alkaline springs (Neal and Stanger, EPSL 1983) can be found over thousands of sq km of outcropping ophiolite. While the deposits in Oman and the Philippines are well-known to much of the geochemical community, little interest seems to have been displayed toward either the ophiolitic occurrences or the submarine deposits for energy production. This may be a mistake as the showings because they could lead to an important source of green energy. Widespread skepticism currently exists about hydrogen as a primary energy source. It is commonly said that free hydrogen does not occur on earth and that it is therefore necessary to use other sources of energy to produce hydrogen, obviating the general environmental benefit. However the existence of numerous occurrences of hydrogen gas associated with ophiolites and submarine occurrences of hydrogen suggests the likelihood that natural hydrogen gas may be an important source of clean energy for modern society remaining to be tapped. Calculations in progress should establish whether or not this is likely to be the case.

  4. Enzymatic production of hydrogen gas from glucose and cellulose

    SciTech Connect

    Mattingly, S.M.; Woodward, J.

    1996-10-01

    An enzymatic process has been used to convert glucose to molecular hydrogen with the ultimate goal of converting cellulose to hydrogen. Two enzymes from the Archae, Thermoplasma acidophilium glucose dehydrogenase (GDH) and Pyrococcus furiosus hydrogenase, were used to oxidize glucose and NADPH respectively, resulting in the formation of molecular hydrogen. The stoichiometric yield of hydrogen from glucose was close to the theoretical maximum expected. Further, the molar amount of hydrogen produced was greater than the molar equivalent of NADP{sup +} present in the reaction mixture indicating that this GDH cofactor was regenerated throughout the course of the reaction. Hydrogen was also shown to be produced from cellulose if cellulase was included in the reaction mixture.

  5. A pyrolysis/gas chromatographic method for the determination of hydrogen in solid samples

    NASA Technical Reports Server (NTRS)

    Carr, R. H.; Bustin, R.; Gibson, E. K.

    1987-01-01

    A method is described for the determination of hydrogen in solid samples. The sample is heated under vacuum after which the evolved gases are separated by gas chromatography with a helium ionization detector. The system is calibrated by injecting known amounts of hydrogen, as determined manometrically. The method, which is rapid and reliable, was checked for a variety of lunar soils; the limit of detection is about 10 ng of hydrogen.

  6. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: BIOQUELL, INC. CLARIS C HYDROGEN PEROXIDE GAS GENERATOR

    EPA Science Inventory

    The Environmental Technology Verification report discusses the technology and performance of the Clarus C Hydrogen Peroxide Gas Generator, a biological decontamination device manufactured by BIOQUELL, Inc. The unit was tested by evaluating its ability to decontaminate seven types...

  7. Viscosity Measurement of Hydrogen-Methane Mixed Gas for Future Energy Systems

    NASA Astrophysics Data System (ADS)

    Kobayashi, Yohei; Kurokawa, Akira; Hirata, Masaru

    In order to reduce the CO2 emission, in May 2004, the European Union (EU) started an experimental approach known as the “naturalhy Project” in order to transport hydrogen by mixing it with the existing high-pressure natural gas in the pipelines. Naturalhy represents a mixture of hydrogen and natural gas. In other words, this gas is also known as hythane, which is an abbreviation of hydrogen and methane. The name “hythane” is the registered trademark of Hydrogen Consulting Inc., USA. Why will this gas gain importance? It is generally considered that the sudden realization of a hydrogen energy society cannot take place. It is normally assumed that the present status of methane as an energy carrier gradually changes to a state of hydrogen-methane mixed gas and finally to 100% hydrogen. This is why the authors investigate the properties of this mixture. This study is considered to be the first to measure the temperature dependence of the viscosity of hydrogen-methane mixed gas. In order to measure the viscosity, the authors used a capillary method that measures the pressure drop in the laminar flow through a pipe. It was conducted in an electrically polished, ultra clean and smooth tube and the pressure drop between the upstream and downstream was carefully measured using a capacitance manometer. In order to remove the effect of temperature dependence, the tube was placed in a constant temperature bath, and the temperature fluctuation was maintained within ±0.3°C throughout this experimental study. The authors obtained the viscosity of the hydrogen-methane mixed gas within a temperature range of 20-70°C.

  8. Gas chromatographic separation of hydrogen isotopes using metal hydrides

    SciTech Connect

    Aldridge, F.T.

    1984-05-09

    A study was made of the properties of metal hydrides which may be suitable for use in chromatographic separation of hydrogen isotopes. Sixty-five alloys were measured, with the best having a hydrogen-deuterium separation factor of 1.35 at 60/sup 0/C. Chromatographic columns using these alloys produced deuterium enrichments of up to 3.6 in a single pass, using natural abundance hydrogen as starting material. 25 references, 16 figures, 4 tables.

  9. Hydrogen Sensors Boost Hybrids; Today's Models Losing Gas?

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Advanced chemical sensors are used in aeronautic and space applications to provide safety monitoring, emission monitoring, and fire detection. In order to fully do their jobs, these sensors must be able to operate in a range of environments. NASA has developed sensor technologies addressing these needs with the intent of improving safety, optimizing combustion efficiencies, and controlling emissions. On the ground, the chemical sensors were developed by NASA engineers to detect potential hydrogen leaks during Space Shuttle launch operations. The Space Shuttle uses a combination of hydrogen and oxygen as fuel for its main engines. Liquid hydrogen is pumped to the external tank from a storage tank located several hundred feet away. Any hydrogen leak could potentially result in a hydrogen fire, which is invisible to the naked eye. It is important to detect the presence of a hydrogen fire in order to prevent a major accident. In the air, the same hydrogen-leak dangers are present. Stress and temperature changes can cause tiny cracks or holes to form in the tubes that line the Space Shuttle s main engine nozzle. Such defects could allow the hydrogen that is pumped through the nozzle during firing to escape. Responding to the challenges associated with pinpointing hydrogen leaks, NASA endeavored to improve propellant leak-detection capabilities during assembly, pre-launch operations, and flight. The objective was to reduce the operational cost of assembling and maintaining hydrogen delivery systems with automated detection systems. In particular, efforts have been focused on developing an automated hydrogen leak-detection system using multiple, networked hydrogen sensors that are operable in harsh conditions.

  10. A comparison of gettering in single- and multicrystalline silicon for solar cells

    SciTech Connect

    Sopori, B.L.; Jastrzebski, L.; Tan, T.

    1996-05-01

    The differences in the impurity gettering between single and multicrystalline silicon are discussed. These differences arise from impurity-defect interactions that occur during thermal processing of multicrystalline material. A gettering model is proposed to explain the observed behaviour of gettering in multicrystalline cells.

  11. Hydrogen and nitrogen turboexpanders with high gas expansion ratios

    NASA Astrophysics Data System (ADS)

    Davydenkov, I. A.; Davydov, A. B.; Perestoronin, G. A.

    The paper examines the design features of a four-stage hydrogen turboexpander with an expansion ratio of 80 and two-stage nitrogen turboexpander with an expansion ratio of 120. The test results obtained under imitations in air are presented. The adiabatic efficiency of the hydrogen and nitrogen turboexpanders under operating conditions has reached 0,65 and 0, 78, respectively. The use of high-performance high-pressure hydrogen and nitrogen turboexpanders has considerably increased the capacity of a large hydrogen liquefier.

  12. Hydrogen uptake on film surfaces produced by a unique codeposition process

    NASA Astrophysics Data System (ADS)

    Salazar, Kenneth V.; Carroll, David W.; Trkula, Mitchell; Sandoval, Cynthia W.

    2003-05-01

    Hydrogen uptake on several different film surfaces has been achieved by deposition of a conventional hydrogen gettering system via a novel combination of physical vapor deposition (PVD) and chemical vapor deposition (CVD) processes. We decided to use a conventional hydrogen gettering system, developed by Smith and Schicker [J.R. Schicker, AS/KCD Project No. EPN-047620, May 1994], that uses an acetylenic organic compound mixed with carbon supported palladium metal. The organic material, 1,4-bis-(phenylethynyl) benzene (DEB), is mixed with palladium and carbon by employing conventional solid state ceramic preparative techniques. Our novel codeposition process combines PVD and CVD techniques for fabricating thin-film coatings of the palladium-catalyzed DEB hydrogen gettering system. Hydrogen uptake was confirmed by 1H NMR and our novel process lends itself well to placing hydrogen getter onto complex shapes and substrates of various compositions.

  13. Application of CFRP with High Hydrogen Gas Barrier Characteristics to Fuel Tanks of Space Transportation System

    NASA Astrophysics Data System (ADS)

    Yonemoto, Koichi; Yamamoto, Yuta; Okuyama, Keiichi; Ebina, Takeo

    In the future, carbon fiber reinforced plastics (CFRPs) with high hydrogen gas barrier performance will find wide applications in all industrial hydrogen tanks that aim at weight reduction; the use of such materials will be preferred to the use of conventional metallic materials such as stainless steel or aluminum. The hydrogen gas barrier performance of CFRP will become an important issue with the introduction of hydrogen-fuel aircraft. It will also play an important role in realizing fully reusable space transportation system that will have high specific tensile CFRP structures. Such materials are also required for the manufacture of high-pressure hydrogen gas vessels for use in the fuel cell systems of automobiles. This paper introduces a new composite concept that can be used to realize CFRPs with high hydrogen gas barrier performance for applications in the cryogenic tanks of fully reusable space transportation system by the incorporation of a nonmetallic crystal layer, which is actually a dense and highly oriented clay crystal laminate. The preliminary test results show that the hydrogen gas barrier characteristics of this material after cryogenic heat shocks and cyclic loads are still better than those of other polymer materials by approximately two orders of magnitude.

  14. Timing of Getter Material Addition in Cementitious Wasteforms

    NASA Astrophysics Data System (ADS)

    Lawter, A.; Qafoku, N. P.; Asmussen, M.; Neeway, J.; Smith, G. L.

    2015-12-01

    A cementitious waste form, Cast Stone, is being evaluated as a possible supplemental immobilization technology for the Hanford sites's low activity waste (LAW), which contains radioactive 99Tc and 129I, as part of the tank waste cleanup mission. Cast Stone is made of a dry blend 47% blast furnace slag, 45% fly ash, and 8% ordinary Portland cement, mixed with a low-activity waste (LAW). To improve the retention of Tc and/or I in Cast Stone, materials with a high affinity for Tc and/or I, termed "getters," can be added to provide a stable domain for the radionuclides of concern. Previous testing conducted with a variety of getters has identified Tin(II)-Apatite and Silver Exchanged Zeolite as promising candidates for Tc and I, respectively. Investigation into the sequence in which getters are added to Cast Stone was performed following two methods: 1) adding getters to the Cast Stone dry blend, and then mixing with liquid waste, and 2) adding getters to the liquid waste first, followed by addition of the Cast Stone dry blend. Cast Stone monolith samples were prepared with each method and leach tests, following EPA method 1315, were conducted in either distilled water or simulated vadose zone porewater for a period of up to 63 days. The leachate was analyzed for Tc, I, Na, NO3-, NO2- and Cr with ICP-MS, ICP-OES and ion chromatography and the results indicated that the Cast Stone with getter addition in the dry blend mix (method 1) has lower rates of Tc and I leaching. The mechanisms of radionuclide release from the Cast Stone were also investigated with a variety of solid phase characterization techniques of the monoliths before and after leaching, such as XRD, SEM/EDS, TEM/SAED and other spectroscopic techniques.

  15. Empirical Method to Estimate Hydrogen Embrittlement of Metals as a Function of Hydrogen Gas Pressure at Constant Temperature

    NASA Technical Reports Server (NTRS)

    Lee, Jonathan A.

    2010-01-01

    High pressure Hydrogen (H) gas has been known to have a deleterious effect on the mechanical properties of certain metals, particularly, the notched tensile strength, fracture toughness and ductility. The ratio of these properties in Hydrogen as compared to Helium or Air is called the Hydrogen Environment Embrittlement (HEE) Index, which is a useful method to classify the severity of H embrittlement and to aid in the material screening and selection for safety usage H gas environment. A comprehensive world-wide database compilation, in the past 50 years, has shown that the HEE index is mostly collected at two conveniently high H pressure points of 5 ksi and 10 ksi near room temperature. Since H embrittlement is directly related to pressure, the lack of HEE index at other pressure points has posed a technical problem for the designers to select appropriate materials at a specific H pressure for various applications in aerospace, alternate and renewable energy sectors for an emerging hydrogen economy. Based on the Power-Law mathematical relationship, an empirical method to accurately predict the HEE index, as a function of H pressure at constant temperature, is presented with a brief review on Sievert's law for gas-metal absorption.

  16. Non Evaporable Getter (NEG) Coatings for Vacuum Systems in Synchrotron Radiation Facilities

    NASA Astrophysics Data System (ADS)

    Manini, Paolo; Conte, Andrea; Raimondi, Stefano; Bonucci, Antonio

    2007-01-01

    Non evaporable Getter (NEG) films, sputter deposited onto the internal surfaces of vacuum chambers, have been proposed by CERN to substantially reduce the gas pressure in UHV-XHV systems. The NEG film acts as a conductance-free distributed pump inside a chamber. Being a barrier for gases it also reduces thermal out-gassing, thus allowing the achievement of very demanding pressure conditions. These features are ideal for very narrow, conductance limited chambers, like Insertion Devices, which cannot be always efficiently pumped by ordinary means. Recent investigations have also shown that NEG coatings do present additional interesting features, like low secondary electron yield and low gas de-sorption rates under ions, electrons and photons bombardment, compared to traditional technical surfaces. Experimental tests, carried out in several high energy machines and synchrotron radiations facilities have so far confirmed the benefits of NEG films in term of better vacuum, longer beam life time and stability, simplified machine design, reduced conditioning time and overall improved machine performances. For these reasons, NEG coating technology is now gaining increasing attention and it is seriously considered for upgrades in a number of machines and for future projects. In the present paper, we report SAES getters experience on NEG coating of chambers of different geometries, materials and sizes for a variety of projects related to synchrotron radiation facilities. Examples of applications in various machines, as well as typical issues related to chambers preparation, film deposition, quality control and characterization, are given.

  17. Fast-quench reactor for hydrogen and elemental carbon production from natural gas and other hydrocarbons

    DOEpatents

    Detering, Brent A.; Kong, Peter C.

    2006-08-29

    A fast-quench reactor for production of diatomic hydrogen and unsaturated carbons is provided. During the fast quench in the downstream diverging section of the nozzle, such as in a free expansion chamber, the unsaturated hydrocarbons are further decomposed by reheating the reactor gases. More diatomic hydrogen is produced, along with elemental carbon. Other gas may be added at different stages in the process to form a desired end product and prevent back reactions. The product is a substantially clean-burning hydrogen fuel that leaves no greenhouse gas emissions, and elemental carbon that may be used in powder form as a commodity for several processes.

  18. Hydrogen and elemental carbon production from natural gas and other hydrocarbons

    DOEpatents

    Detering, Brent A.; Kong, Peter C.

    2002-01-01

    Diatomic hydrogen and unsaturated hydrocarbons are produced as reactor gases in a fast quench reactor. During the fast quench, the unsaturated hydrocarbons are further decomposed by reheating the reactor gases. More diatomic hydrogen is produced, along with elemental carbon. Other gas may be added at different stages in the process to form a desired end product and prevent back reactions. The product is a substantially clean-burning hydrogen fuel that leaves no greenhouse gas emissions, and elemental carbon that may be used in powder form as a commodity for several processes.

  19. Impurity Gettering Effect of Te Inclusions in Cdznte Single Crystals

    SciTech Connect

    Yang, G.; Bolotnikov, A; Cui, Y; Camarda, G; Hossain, A; James, R

    2009-01-01

    The local impurity distribution in Te inclusions of CdZnTe (CZT) crystal was investigated by the time-of-flight secondary ion mass spectrometry (Tof-SIMS) technique. Direct evidence of impurity gettering in Te inclusions has been observed for the first time. The impurity gettering in Te inclusions originated from the diffusion mechanism during crystal growth and segregation mechanism during crystal cooling. This phenomenon is meaningful, because it reveals how Te inclusions affect CZT properties and provides a possible approach to reduce the impurities in CZT by the way of removing Te inclusions.

  20. Direct chlorination process for geothermal power plant off-gas - hydrogen sulfide abatement

    SciTech Connect

    Sims, A.V.

    1983-06-01

    The Direct Chlorination Process removes hydrogen sulfide from geothermal off-gases by reacting hydrogen sulfide with chlorine in the gas phase. Hydrogen chloride and elemental sulfur are formed by this reaction. The Direct Chlorination Process has been successfully demonstrated by an on-site operation of a pilot plant at the 3 M We HPG-A geothermal power plant in the Puna District on the island of Hawaii. Over 99.5 percent hydrogen sulfide removal was achieved in a single reaction stage. Chlorine gas did not escape the pilot plant, even when 90 percent excess chlorine gas was used. Because of the higher cost of chemicals and the restricted markets in Hawaii, the economic viability of this process in Hawaii is questionable.

  1. Direct chlorination process for geothermal power plant off-gas - hydrogen sulfide abatement

    SciTech Connect

    Sims, A.V.

    1983-06-01

    The Direct Chlorination Process removes hydrogen sulfide from geothermal off-gases by reacting hydrogen sulfide with chlorine in the gas phase. Hydrogen chloride and elemental sulfur are formed by this reaction. The Direct Chlorination Process has been successfully demonstrated by an on-site operation of a pilot plant at the 3 M We HPG-A geothermal power plant in the Puna District on the island of Hawaii. Over 99.5 percent hydrogen sulfide removal was achieved in a single reaction state. Chlorine gas did not escape the pilot plant, even when 90 percent excess chlorine gas was used. A preliminary economic evaluation of the Direct Chlorination Process indicates that it is very competitive with the Stretford Process. Compared to the Stretford Process, the Direct Chlorination Process requires about one-third the initial capital investment and about one-fourth the net daily expenditure.

  2. Assembly of thermally reduced graphene oxide nanostructures by alternating current dielectrophoresis as hydrogen-gas sensors

    NASA Astrophysics Data System (ADS)

    Wang, Jianwei; Singh, Budhi; Maeng, Sunglyul; Joh, Han-Ik; Kim, Gil-Ho

    2013-08-01

    Chemo-resistive hydrogen-gas sensors based on thermally reduced graphene oxide (rGO) have been fabricated on a micro-hotplate by positive ac dielectrophoresis (DEP). The optimized DEP parameters for manipulating rGO nanostructures into Au electrodes for hydrogen sensing are: applied frequency = 1 MHz, peak-to-peak voltage = 5 V, and DEP time = 30 s. The device exhibits good sensitivity (˜6%) with fast response time (˜11 s) and recovery time (˜36 s) for 200 ppm hydrogen gas at room temperature. This result indicates that the DEP process has great potential for assembling rGO for hydrogen-gas sensor in many industrial and scientific applications.

  3. Hydrogen gas reduces hyperoxic lung injury via the Nrf2 pathway in vivo

    PubMed Central

    Kawamura, Tomohiro; Wakabayashi, Nobunao; Shigemura, Norihisa; Huang, Chien-Sheng; Masutani, Kosuke; Tanaka, Yugo; Noda, Kentaro; Peng, Ximei; Takahashi, Toru; Billiar, Timothy R.; Okumura, Meinoshin; Toyoda, Yoshiya; Kensler, Thomas W.

    2013-01-01

    Hyperoxic lung injury is a major concern in critically ill patients who receive high concentrations of oxygen to treat lung diseases. Successful abrogation of hyperoxic lung injury would have a huge impact on respiratory and critical care medicine. Hydrogen can be administered as a therapeutic medical gas. We recently demonstrated that inhaled hydrogen reduced transplant-induced lung injury and induced heme oxygenase (HO)-1. To determine whether hydrogen could reduce hyperoxic lung injury and investigate the underlying mechanisms, we randomly assigned rats to four experimental groups and administered the following gas mixtures for 60 h: 98% oxygen (hyperoxia), 2% nitrogen; 98% oxygen (hyperoxia), 2% hydrogen; 98% balanced air (normoxia), 2% nitrogen; and 98% balanced air (normoxia), 2% hydrogen. We examined lung function by blood gas analysis, extent of lung injury, and expression of HO-1. We also investigated the role of NF-E2-related factor (Nrf) 2, which regulates HO-1 expression, by examining the expression of Nrf2-dependent genes and the ability of hydrogen to reduce hyperoxic lung injury in Nrf2-deficient mice. Hydrogen treatment during exposure to hyperoxia significantly improved blood oxygenation, reduced inflammatory events, and induced HO-1 expression. Hydrogen did not mitigate hyperoxic lung injury or induce HO-1 in Nrf2-deficient mice. These findings indicate that hydrogen gas can ameliorate hyperoxic lung injury through induction of Nrf2-dependent genes, such as HO-1. The findings suggest a potentially novel and applicable solution to hyperoxic lung injury and provide new insight into the molecular mechanisms and actions of hydrogen. PMID:23475767

  4. Performance of a Small Gas Generator Using Liquid Hydrogen and Liquid Oxygen

    NASA Technical Reports Server (NTRS)

    Acker, Loren W.; Fenn, David B.; Dietrich, Marshall W.

    1961-01-01

    The performance and operating problems of a small hot-gas generator burning liquid hydrogen with liquid oxygen are presented. Two methods of ignition are discussed. Injector and combustion chamber design details based on rocket design criteria are also given. A carefully fabricated showerhead injector of simple design provided a gas generator that yielded combustion efficiencies of 93 and 96 percent.

  5. Impurity gettering in silicon using cavities formed by helium implantation and annealing

    DOEpatents

    Myers, S.M. Jr.; Bishop, D.M.; Follstaedt, D.M.

    1998-11-24

    Impurity gettering in silicon wafers is achieved by a new process consisting of helium ion implantation followed by annealing. This treatment creates cavities whose internal surfaces are highly chemically reactive due to the presence of numerous silicon dangling bonds. For two representative transition-metal impurities, copper and nickel, the binding energies at cavities were demonstrated to be larger than the binding energies in precipitates of metal silicide, which constitutes the basis of most current impurity gettering. As a result the residual concentration of such impurities after cavity gettering is smaller by several orders of magnitude than after precipitation gettering. Additionally, cavity gettering is effective regardless of the starting impurity concentration in the wafer, whereas precipitation gettering ceases when the impurity concentration reaches a characteristic solubility determined by the equilibrium phase diagram of the silicon-metal system. The strong cavity gettering was shown to induce dissolution of metal-silicide particles from the opposite side of a wafer. 4 figs.

  6. Impurity gettering in silicon using cavities formed by helium implantation and annealing

    DOEpatents

    Myers, Jr., Samuel M.; Bishop, Dawn M.; Follstaedt, David M.

    1998-01-01

    Impurity gettering in silicon wafers is achieved by a new process consisting of helium ion implantation followed by annealing. This treatment creates cavities whose internal surfaces are highly chemically reactive due to the presence of numerous silicon dangling bonds. For two representative transition-metal impurities, copper and nickel, the binding energies at cavities were demonstrated to be larger than the binding energies in precipitates of metal silicide, which constitutes the basis of most current impurity gettering. As a result the residual concentration of such impurities after cavity gettering is smaller by several orders of magnitude than after precipitation gettering. Additionally, cavity gettering is effective regardless of the starting impurity concentration in the wafer, whereas precipitation gettering ceases when the impurity concentration reaches a characteristic solubility determined by the equilibrium phase diagram of the silicon-metal system. The strong cavity gettering was shown to induce dissolution of metal-silicide particles from the opposite side of a wafer.

  7. 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.

  8. Anaerobic and Aerobic Hydrogen Gas Formation by the Blue-Green Alga Anabaena cylindrica

    PubMed Central

    Daday, Arlene; Platz, Rosalea A.; Smith, Geoffrey D.

    1977-01-01

    An investigation was made of certain factors involved in the formation of hydrogen gas, both in an anaerobic environment (argon) and in air, by the blue-green alga Anabaena cylindrica. The alga had not been previously adapted under hydrogen gas and hence the hydrogen evolution occurred entirely within the nitrogen-fixing heterocyst cells; organisms grown in a fixed nitrogen source, and which were therefore devoid of heterocysts, did not produce hydrogen under these conditions. Use of the inhibitor dichlorophenyl-dimethyl urea showed that hydrogen formation was directly dependent on photosystem I and only indirectly dependent on photosystem II, consistent with heterocysts being the site of hydrogen formation. The uncouplers carbonyl cyanide chlorophenyl hydrazone and dinitrophenol almost completely inhibited hydrogen formation, indicating that the process occurs almost entirely via the adenosine 5′-triphosphate-dependent nitrogenase. Salicylaldoxime also inhibited hydrogen formation, again illustrating the necessity of photophosphorylation. Whereas hydrogen formation could usually only be observed in anaerobic, dinitrogen-free environments, incubation in the presence of the dinitrogen-fixing inhibitor carbon monoxide plus the hydrogenase inhibitor acetylene resulted in significant formation of hydrogen even in air. Hydrogen formation was studied in batch cultures as a function of age of the cultures and also as a function of culture concentration, in both cases the cultures being harvested in logarithmic growth. Hydrogen evolution (and acetylene-reducing activity) exhibited a distinct maximum with respect to the age of the cultures. Finally, the levels of the protective enzyme, superoxide dismutase, were measured in heterocyst and vegetative cell fractions of the organism; the level was twice as high in heterocyst cells (2.3 units/mg of protein) as in vegetative cells (1.1 units/mg of protein). A simple procedure for isolating heterocyst cells is described. PMID

  9. Hydrogen Energy Storage (HES) and Power-to-Gas Economic Analysis; NREL (National Renewable Energy Laboratory)

    SciTech Connect

    Eichman, Joshua

    2015-07-30

    This presentation summarizes opportunities for hydrogen energy storage and power-to-gas and presents the results of a market analysis performed by the National Renewable Energy Laboratory to quantify the value of energy storage. Hydrogen energy storage and power-to-gas systems have the ability to integrate multiple energy sectors including electricity, transportation, and industrial. On account of the flexibility of hydrogen systems, there are a variety of potential system configurations. Each configuration will provide different value to the owner, customers and grid system operator. This presentation provides an economic comparison of hydrogen storage, power-to-gas and conventional storage systems. The total cost is compared to the revenue with participation in a variety of markets to assess the economic competitiveness. It is found that the sale of hydrogen for transportation or industrial use greatly increases competitiveness. Electrolyzers operating as demand response devices (i.e., selling hydrogen and grid services) are economically competitive, while hydrogen storage that inputs electricity and outputs only electricity have an unfavorable business case. Additionally, tighter integration with the grid provides greater revenue (e.g., energy, ancillary service and capacity markets are explored). Lastly, additional hours of storage capacity is not necessarily more competitive in current energy and ancillary service markets and electricity markets will require new mechanisms to appropriately compensate long duration storage devices.

  10. On the formation of hydrogen gas on copper in anoxic water

    NASA Astrophysics Data System (ADS)

    Johansson, Adam Johannes; Lilja, Christina; Brinck, Tore

    2011-08-01

    Hydrogen gas has been detected in a closed system containing copper and pure anoxic water [P. Szakalos, G. Hultquist, and G. Wikmark, Electrochem. Solid-State Lett. 10, C63 (2007), 10.1149/1.2772085 and G. Hultquist, P. Szakalos, M. Graham, A. Belonoshko, G. Sproule, L. Grasjo, P. Dorogokupets, B. Danilov, T. Aastrup, G. Wikmark, G. Chuah, J. Eriksson, and A. Rosengren, Catal. Lett. 132, 311 (2009), 10.1007/s10562-009-0113-x]. Although bulk corrosion into any of the known phases of copper is thermodynamically forbidden, the present paper shows how surface reactions lead to the formation of hydrogen gas in limited amounts. While water cleavage on copper has been reported and investigated before, formation of molecular hydrogen at a single-crystal Cu[100] surface is here explored using density functional theory and transition state theory. It is found that although solvent catalysis seems possible, the fastest route to the formation of molecular hydrogen is the direct combination of hydrogen atoms on the copper surface. The activation free energy (△Gs‡f) of hydrogen formation in condensed phase is 0.70 eV, which corresponds to a rate constant of 10 s-1 at 298.15 K, i.e., a relatively rapid process. It is estimated that at least 2.4 ng hydrogen gas could form per cm2 on a perfect copper surface.

  11. Mechanical Properties of Super Duplex Stainless Steel 2507 after Gas Phase Thermal Precharging with Hydrogen

    NASA Astrophysics Data System (ADS)

    San Marchi, C.; Somerday, B. P.; Zelinski, J.; Tang, X.; Schiroky, G. H.

    2007-11-01

    Thermal precharging of super duplex stainless steel 2507 with 125 wppm hydrogen significantly reduced tensile ductility and fracture toughness. Strain-hardened 2507 exhibited more severe ductility loss compared to the annealed microstructure. The reduction of area (RA) was between 80 and 85 pct for both microstructures in the noncharged condition, while reductions of area were 25 and 46 pct for the strain-hardened and annealed microstructures, respectively, after hydrogen precharging. Similar to the effect of internal hydrogen on tensile ductility, fracture toughness of strain-hardened 2507 was lowered from nearly 300 MPa m1/2 in the noncharged condition to less than 60 MPa m1/2 in the hydrogen-precharged condition. While precharging 2507 with hydrogen results in a considerable reduction in ductility and toughness, the absolute values are similar to high-strength austenitic steels that have been tested under the same conditions, and which are generally considered acceptable for high-pressure hydrogen gas systems. The fracture mode in hydrogen-precharged 2507 involved cleavage cracking of the ferrite phase and ductile fracture along oblique planes in the austenite phase, compared to 100 pct microvoid coalescence in the absence of hydrogen. Predictions from a strain-based micromechanical fracture toughness model were in good agreement with the measured fracture toughness of hydrogen-precharged 2507, implying a governing role of austenite for resistance to hydrogen-assisted fracture.

  12. Multi-Walled Carbon Nanotube-Doped Tungsten Oxide Thin Films for Hydrogen Gas Sensing

    PubMed Central

    Wongchoosuk, Chatchawal; Wisitsoraat, Anurat; Phokharatkul, Ditsayut; Tuantranont, Adisorn; Kerdcharoen, Teerakiat

    2010-01-01

    In this work we have fabricated hydrogen gas sensors based on undoped and 1 wt% multi-walled carbon nanotube (MWCNT)-doped tungsten oxide (WO3) thin films by means of the powder mixing and electron beam (E-beam) evaporation technique. Hydrogen sensing properties of the thin films have been investigated at different operating temperatures and gas concentrations ranging from 100 ppm to 50,000 ppm. The results indicate that the MWCNT-doped WO3 thin film exhibits high sensitivity and selectivity to hydrogen. Thus, MWCNT doping based on E-beam co-evaporation was shown to be an effective means of preparing hydrogen gas sensors with enhanced sensing and reduced operating temperatures. Creation of nanochannels and formation of p-n heterojunctions were proposed as the sensing mechanism underlying the enhanced hydrogen sensitivity of this hybridized gas sensor. To our best knowledge, this is the first report on a MWCNT-doped WO3 hydrogen sensor prepared by the E-beam method. PMID:22163623

  13. PALLADIUM DOPED TIN OXIDE BASED HYDROGEN GAS SENSORS FOR SAFETY APPLICATIONS

    SciTech Connect

    Kasthurirengan, S.; Behera, Upendra; Nadig, D. S.

    2010-04-09

    Hydrogen is considered to be a hazardous gas since it forms a flammable mixture between 4 to 75% by volume in air. Hence, the safety aspects of handling hydrogen are quite important. For this, ideally, highly selective, fast response, small size, hydrogen sensors are needed. Although sensors based on different technologies may be used, thin-film sensors based on palladium (Pd) are preferred due to their compactness and fast response. They detect hydrogen by monitoring the changes to the electrical, mechanical or optical properties of the films. We report the development of Pd-doped tin-oxide based gas sensors prepared on thin ceramic substrates with screen printed platinum (Pt) contacts and integrated nicrome wire heaters. The sensors are tested for their performances using hydrogen-nitrogen gas mixtures to a maximum of 4%H{sub 2} in N{sub 2}. The sensors detect hydrogen and their response times are less than a few seconds. Also, the sensor performance is not altered by the presence of helium in the test gas mixtures. By the above desired performance characteristics, field trials of these sensors have been undertaken. The paper presents the details of the sensor fabrication, electronic circuits, experimental setup for evaluation and the test results.

  14. Nuclear breeder reactor fuel element with silicon carbide getter

    DOEpatents

    Christiansen, David W.; Karnesky, Richard A.

    1987-01-01

    An improved cesium getter 28 is provided in a breeder reactor fuel element or pin in the form of an extended surface area, low density element formed in one embodiment as a helically wound foil 30 located with silicon carbide, and located at the upper end of the fertile material upper blanket 20.

  15. Exceptional gettering response of epitaxially grown kerfless silicon

    DOE PAGES

    Powell, D. M.; Markevich, V. P.; Hofstetter, J.; Jensen, M. A.; Morishige, A. E.; Castellanos, S.; Lai, B.; Peaker, A. R.; Buonassisi, T.

    2016-02-08

    The bulk minority-carrier lifetime in p- and n-type kerfless epitaxial (epi) crystalline silicon wafers is shown to increase >500 during phosphorus gettering. We employ kinetic defect simulations and microstructural characterization techniques to elucidate the root cause of this exceptional gettering response. Simulations and deep-level transient spectroscopy (DLTS) indicate that a high concentra- tion of point defects (likely Pt) is “locked in” during fast (60 C/min) cooling during epi wafer growth. The fine dispersion of moderately fast-diffusing recombination-active point defects limits as-grown lifetime but can also be removed during gettering, confirmed by DLTS measurements. Synchrotron-based X-ray fluorescence microscopy indicates metal agglomeratesmore » at structural defects, yet the structural defect density is sufficiently low to enable high lifetimes. Consequently, after phosphorus diffusion gettering, epi silicon exhibits a higher lifetime than materials with similar bulk impurity contents but higher densities of structural defects, including multicrystalline ingot and ribbon silicon materials. As a result, device simulations suggest a solar-cell efficiency potential of this material >23%.« less

  16. Exceptional gettering response of epitaxially grown kerfless silicon

    NASA Astrophysics Data System (ADS)

    Powell, D. M.; Markevich, V. P.; Hofstetter, J.; Jensen, M. A.; Morishige, A. E.; Castellanos, S.; Lai, B.; Peaker, A. R.; Buonassisi, T.

    2016-02-01

    The bulk minority-carrier lifetime in p- and n-type kerfless epitaxial (epi) crystalline silicon wafers is shown to increase >500× during phosphorus gettering. We employ kinetic defect simulations and microstructural characterization techniques to elucidate the root cause of this exceptional gettering response. Simulations and deep-level transient spectroscopy (DLTS) indicate that a high concentration of point defects (likely Pt) is "locked in" during fast (60 °C/min) cooling during epi wafer growth. The fine dispersion of moderately fast-diffusing recombination-active point defects limits as-grown lifetime but can also be removed during gettering, confirmed by DLTS measurements. Synchrotron-based X-ray fluorescence microscopy indicates metal agglomerates at structural defects, yet the structural defect density is sufficiently low to enable high lifetimes. Consequently, after phosphorus diffusion gettering, epi silicon exhibits a higher lifetime than materials with similar bulk impurity contents but higher densities of structural defects, including multicrystalline ingot and ribbon silicon materials. Device simulations suggest a solar-cell efficiency potential of this material >23%.

  17. Molecular hydrogen: An inert gas turns clinically effective.

    PubMed

    Ostojic, Sergej M

    2015-06-01

    Molecular hydrogen (H2) appeared as an experimental agent in biomedicine approximately 40 years ago, yet the past 5 years seem to confirm its medicinal value in the clinical environment. H2 improves clinical end-points and surrogate markers in several clinical trials, from metabolic diseases to chronic systemic inflammatory disorders to cancer. However, less information is available concerning its medicinal properties, such as dosage and administration, or adverse reactions and use in specific populations. The present paper overviews the clinical relevance of molecular hydrogen, and summarizes data from clinical trials on this innovative medical agent. Clinical profiles of H2 provide evidence-based direction for practical application and future research on molecular hydrogen for the wider health care community.

  18. Molecular hydrogen: An inert gas turns clinically effective.

    PubMed

    Ostojic, Sergej M

    2015-06-01

    Molecular hydrogen (H2) appeared as an experimental agent in biomedicine approximately 40 years ago, yet the past 5 years seem to confirm its medicinal value in the clinical environment. H2 improves clinical end-points and surrogate markers in several clinical trials, from metabolic diseases to chronic systemic inflammatory disorders to cancer. However, less information is available concerning its medicinal properties, such as dosage and administration, or adverse reactions and use in specific populations. The present paper overviews the clinical relevance of molecular hydrogen, and summarizes data from clinical trials on this innovative medical agent. Clinical profiles of H2 provide evidence-based direction for practical application and future research on molecular hydrogen for the wider health care community. PMID:25936365

  19. Purification of liquid metal systems with sodium coolant from oxygen using getters

    NASA Astrophysics Data System (ADS)

    Kozlov, F. A.; Konovalov, M. A.; Sorokin, A. P.

    2016-05-01

    For increasing the safety and economic parameters of nuclear power stations (NPSs) with sodium coolant, it was decided to install all systems contacting radioactive sodium, including purification systems of circuit I, in the reactor vessel. The performance and capacity of cold traps (CTs) (conventional element of coolant purification systems) in these conditions are limited by their volume. It was proposed to use hot traps (HTs) in circuit I for coolant purification from oxygen. It was demonstrated that, at rated parameters of the installation when the temperature of the coolant streamlining the getter (gas absorber) is equal to 550°C, the hot trap can provide the required coolant purity. In shutdown modes at 250-300°C, the performance of the hot trap is reduced by four orders of magnitude. Possible HT operation regimes for shutdown modes and while reaching rated parameters were proposed and analyzed. Basic attention was paid to purification modes at power rise after commissioning and accidental contamination of the coolant when the initial oxygen concentration in it reached 25 mln-1. It was demonstrated that the efficiency of purification systems can be increased using HTs with the getter in the form of a foil or granules. The possibility of implementing the "fast purification" mode in which the coolant is purified simultaneously with passing over from the shutdown mode to the rated parameters was substantiated.

  20. Use of non evaporable getter pumps to ensure long term performances of high quantum efficiency photocathodes

    SciTech Connect

    Sertore, Daniele Michelato, Paolo; Monaco, Laura; Manini, Paolo; Siviero, Fabrizio

    2014-05-15

    High quantum efficiency photocathodes are routinely used as laser triggered emitters in the advanced high brightness electron sources based on radio frequency guns. The sensitivity of “semiconductor” type photocathodes to vacuum levels and gas composition requires special care during preparation and handling. This paper will discuss the results obtained using a novel pumping approach based on coupling a 20 l s{sup −1} sputter ion getter pump with a CapaciTorr® D100 non evaporable getter (NEG) pump. A pressure of 8⋅10{sup −8} Pa was achieved using only a sputter ion pump after a 6 day bake-out. With the addition of a NEG pump, a pressure of 2⋅10{sup −9} Pa was achieved after a 2 day bake-out. These pressure values were maintained without power due to the ability of the NEG to pump gases by chemical reaction. Long term monitoring of cathodes quantum efficiencies was also carried out at different photon wavelengths for more than two years, showing no degradation of the photoemissive film properties.

  1. A study of the critical nozzle for flow rate measurement of high-pressure hydrogen gas

    NASA Astrophysics Data System (ADS)

    Kim, H. D.; Lee, J. H.; Park, K. A.; Setoguchi, T.; Matsuo, S.

    2007-03-01

    The mass flow rate measurement using a critical nozzle shows the validity of the inviscid theory, indicating that the discharge coefficient increases and approaches unity as the Reynolds number increases under the ideal gas law. However, when the critical nozzle measures the mass flow rate of a real gas such as hydrogen at a pressure of hundreds bar, the discharge coefficient exceeds unity, and the real gas effects should be taken into account. The present study aims at investigating the flow features of the critical nozzle using high-pressured hydrogen gas. The axisymmetric, compressible Navier-Stokes computation is employed to simulate the critical nozzle flow, and a fully implicit finite volume method is used to discretize the governing equation system. The real gas effects are simulated to consider the intermolecular forces, which account for the possibility of liquefying hydrogen gas. The computational results are compared with past experimental data. It has been found that the coefficient of discharge for real gas can be corrected properly below unity adopting the real gas assumption.

  2. Cerebral arterial gas embolism after pre-flight ingestion of hydrogen peroxide.

    PubMed

    Smedley, Ben L; Gault, Alan; Gawthrope, Ian C

    2016-06-01

    Cerebral arterial gas embolism (CAGE) is a feared complication of ambient depressurisation and can also be a complication of hydrogen peroxide ingestion. We present an unusual case of CAGE in a 57-year-old woman exposed to both of these risk factors. We describe her subsequent successful treatment with hyperbaric oxygen, despite a 72-hour delay in initial presentation and diagnosis, and discuss the safety of aero-medical transfer following hydrogen peroxide ingestions.

  3. Cerebral arterial gas embolism after pre-flight ingestion of hydrogen peroxide.

    PubMed

    Smedley, Ben L; Gault, Alan; Gawthrope, Ian C

    2016-06-01

    Cerebral arterial gas embolism (CAGE) is a feared complication of ambient depressurisation and can also be a complication of hydrogen peroxide ingestion. We present an unusual case of CAGE in a 57-year-old woman exposed to both of these risk factors. We describe her subsequent successful treatment with hyperbaric oxygen, despite a 72-hour delay in initial presentation and diagnosis, and discuss the safety of aero-medical transfer following hydrogen peroxide ingestions. PMID:27335000

  4. Treating landfill gas hydrogen sulphide with mineral wool waste (MWW) and rod mill waste (RMW).

    PubMed

    Bergersen, Ove; Haarstad, Ketil

    2014-01-01

    Hydrogen sulphide (H2S) gas is a major odorant at municipal landfills. The gas can be generated from different waste fractions, for example demolition waste containing gypsum based plaster board. The removal of H2S from landfill gas was investigated by filtering it through mineral wool waste products. The flow of gas varied from 0.3 l/min to 3.0 l/min. The gas was typical for landfill gas with a mean H2S concentration of ca. 4500 ppm. The results show that the sulphide gas can effectively be removed by mineral wool waste products. The ratios of the estimated potential for sulphide precipitation were 19:1 for rod mill waste (RMW) and mineral wool waste (MWW). A filter consisting of a mixture of MWW and RMW, with a vertical perforated gas tube through the center of filter material and with a downward gas flow, removed 98% of the sulfide gas over a period of 80 days. A downward gas flow was more efficient in contacting the filter materials. Mineral wool waste products are effective in removing hydrogen sulphide from landfill gas given an adequate contact time and water content in the filter material. Based on the estimated sulphide removal potential of mineral wool and rod mill waste of 14 g/kg and 261 g/kg, and assuming an average sulphide gas concentration of 4500 ppm, the removal capacity in the filter materials has been estimated to last between 11 and 308 days. At the studied location the experimental gas flow was 100 times less than the actual gas flow. We believe that the system described here can be upscaled in order to treat this gas flow.

  5. NMR properties of hydrogen-bonded glycine cluster in gas phase

    NASA Astrophysics Data System (ADS)

    Carvalho, Jorge R.; da Silva, Arnaldo Machado; Ghosh, Angsula; Chaudhuri, Puspitapallab

    2016-11-01

    Density Functional Theory (DFT) calculations have been performed to study the effect of the hydrogen bond formation on the Nuclear Magnetic Resonance (NMR) parameters of hydrogen-bonded clusters of glycine molecules in gas-phase. DFT predicted isotropic chemical shifts of H, C, N and O of the isolated glycine with respect to standard reference materials are in reasonable agreement with available experimental data. The variations of isotropic and anisotropic chemical shifts for all atoms constituting these clusters containing up to four glycine molecules have been investigated systematically employing gradient corrected hybrid B3LYP functional with three different types of extended basis sets. The clusters are mainly stabilized by a network of strong hydrogen bonds among the carboxylic (COOH) groups of glycine monomers. The formation of hydrogen bond influences the molecular structure of the clusters significantly which, on the other hand, gets reflected in the variations of NMR properties. The carbon (C) atom of the sbnd COOH group, the bridging hydrogen (H) and the proton-donor oxygen (O) atom of the Osbnd H bond suffer downfield shift due to the formation of hydrogen bond. The hydrogen bond lengths and the structural complexity of the clusters are found to vary with the number of participating monomers. A direct correlation between the hydrogen bond length and isotropic chemical shift of the bridging hydrogen is observed in all cases. The individual variations of the principal axis elements in chemical shift tensor provide additional insight about the different nature of the monomers within the cluster.

  6. Self-heated silicon nanowires for high performance hydrogen gas detection.

    PubMed

    Ahn, Jae-Hyuk; Yun, Jeonghoon; Moon, Dong-Il; Choi, Yang-Kyu; Park, Inkyu

    2015-03-01

    Self-heated silicon nanowire sensors for high-performance, ultralow-power hydrogen detection have been developed. A top-down nanofabrication method based on well-established semiconductor manufacturing technology was utilized to fabricate silicon nanowires in wafer scale with high reproducibility and excellent compatibility with electronic readout circuits. Decoration of palladium nanoparticles onto the silicon nanowires enables sensitive and selective detection of hydrogen gas at room temperature. Self-heating of silicon nanowire sensors allows us to enhance response and recovery performances to hydrogen gas, and to reduce the influence of interfering gases such as water vapor and carbon monoxide. A short-pulsed heating during recovery was found to be effective for additional reduction of operation power as well as recovery characteristics. This self-heated silicon nanowire gas sensor will be suitable for ultralow-power applications such as mobile telecommunication devices and wireless sensing nodes.

  7. Microbial electrolysis cells for high yield hydrogen gas production from organic matter.

    PubMed

    Logan, Bruce E; Call, Douglas; Cheng, Shaoan; Hamelers, Hubertus V M; Sleutels, Tom H J A; Jeremiasse, Adriaan W; Rozendal, René A

    2008-12-01

    The use of electrochemically active bacteria to break down organic matter, combined with the addition of a small voltage (> 0.2 V in practice) in specially designed microbial electrolysis cells (MECs), can result in a high yield of hydrogen gas. While microbial electrolysis was invented only a few years ago, rapid developments have led to hydrogen yields approaching 100%, energy yields based on electrical energy input many times greater than that possible by water electrolysis, and increased gas production rates. MECs used to make hydrogen gas are similar in design to microbial fuel cells (MFCs) that produce electricity, but there are important differences in architecture and analytical methods used to evaluate performance. We review here the materials, architectures, performance, and energy efficiencies of these MEC systems that show promise as a method for renewable and sustainable energy production, and wastewater treatment.

  8. Measurement and interpretation of threshold stress intensity factors for steels in high-pressure hydrogen gas.

    SciTech Connect

    Nibur, Kevin A.

    2010-11-01

    Threshold stress intensity factors were measured in high-pressure hydrogen gas for a variety of low alloy ferritic steels using both constant crack opening displacement and rising crack opening displacement procedures. The sustained load cracking procedures are generally consistent with those in ASME Article KD-10 of Section VIII Division 3 of the Boiler and Pressure Vessel Code, which was recently published to guide design of high-pressure hydrogen vessels. Three definitions of threshold were established for the two test methods: K{sub THi}* is the maximum applied stress intensity factor for which no crack extension was observed under constant displacement; K{sub THa} is the stress intensity factor at the arrest position for a crack that extended under constant displacement; and K{sub JH} is the stress intensity factor at the onset of crack extension under rising displacement. The apparent crack initiation threshold under constant displacement, K{sub THi}*, and the crack arrest threshold, K{sub THa}, were both found to be non-conservative due to the hydrogen exposure and crack-tip deformation histories associated with typical procedures for sustained-load cracking tests under constant displacement. In contrast, K{sub JH}, which is measured under concurrent rising displacement and hydrogen gas exposure, provides a more conservative hydrogen-assisted fracture threshold that is relevant to structural components in which sub-critical crack extension is driven by internal hydrogen gas pressure.

  9. Measurement and interpretation of threshold stress intensity factors for steels in high-pressure hydrogen gas.

    SciTech Connect

    Dadfarnia, Mohsen; Nibur, Kevin A.; San Marchi, Christopher W.; Sofronis, Petros; Somerday, Brian P.; Foulk, James W., III; Hayden, Gary A.

    2010-07-01

    Threshold stress intensity factors were measured in high-pressure hydrogen gas for a variety of low alloy ferritic steels using both constant crack opening displacement and rising crack opening displacement procedures. The sustained load cracking procedures are generally consistent with those in ASME Article KD-10 of Section VIII Division 3 of the Boiler and Pressure Vessel Code, which was recently published to guide design of high-pressure hydrogen vessels. Three definitions of threshold were established for the two test methods: K{sub THi}* is the maximum applied stress intensity factor for which no crack extension was observed under constant displacement; K{sub THa} is the stress intensity factor at the arrest position for a crack that extended under constant displacement; and K{sub JH} is the stress intensity factor at the onset of crack extension under rising displacement. The apparent crack initiation threshold under constant displacement, K{sub THi}*, and the crack arrest threshold, K{sub THa}, were both found to be non-conservative due to the hydrogen exposure and crack-tip deformation histories associated with typical procedures for sustained-load cracking tests under constant displacement. In contrast, K{sub JH}, which is measured under concurrent rising displacement and hydrogen gas exposure, provides a more conservative hydrogen-assisted fracture threshold that is relevant to structural components in which sub-critical crack extension is driven by internal hydrogen gas pressure.

  10. Low-Dimensional Palladium Nanostructures for Fast and Reliable Hydrogen Gas Detection

    PubMed Central

    Noh, Jin-Seo; Lee, Jun Min; Lee, Wooyoung

    2011-01-01

    Palladium (Pd) has received attention as an ideal hydrogen sensor material due to its properties such as high sensitivity and selectivity to hydrogen gas, fast response, and operability at room temperature. Interestingly, various Pd nanostructures that have been realized by recent developments in nanotechnologies are known to show better performance than bulk Pd. This review highlights the characteristic properties, issues, and their possible solutions of hydrogen sensors based on the low-dimensional Pd nanostructures with more emphasis on Pd thin films and Pd nanowires. The finite size effects, relative strengths and weaknesses of the respective Pd nanostructures are discussed in terms of performance, manufacturability, and practical applicability. PMID:22346605

  11. In situ Gas Conditioning in Fuel Reforming for Hydrogen Generation

    SciTech Connect

    Bandi, A.; Specht, M.; Sichler, P.; Nicoloso, N.

    2002-09-20

    The production of hydrogen for fuel cell applications requires cost and energy efficient technologies. The Absorption Enhanced Reforming (AER), developed at ZSW with industrial partners, is aimed to simplify the process by using a high temperature in situ CO2 absorption. The in situ CO2 removal results in shifting the steam reforming reaction equilibrium towards increased hydrogen concentration (up to 95 vol%). The key part of the process is the high temperature CO2 absorbent. In this contribution results of Thermal Gravimetric Analysis (TGA) investigations on natural minerals, dolomites, silicates and synthetic absorbent materials in regard of their CO2 absorption capacity and absorption/desorption cyclic stability are presented and discussed. It has been found that the inert parts of the absorbent materials have a structure stabilizing effect, leading to an improved cyclic stability of the materials.

  12. Alignment of graphene oxide nanostructures between microgap electrodes via dielectrophoresis for hydrogen gas sensing applications

    SciTech Connect

    Singh, Budhi; Wang, Jianwei; Rathi, Servin; Kim, Gil-Ho

    2015-05-18

    Graphene oxide (GO) nanostructures have been aligned between conducting electrodes via dielectrophoresis (DEP) with different electrical configurations. The arrangement of ground with respect to peak-to-peak voltage (V{sub pp}) plays a crucial role in manipulating the GO nanostructures. Grounds on both sides of the V{sub pp} electrode give an excellent linking of GO nanostructures which is explained by scanning electron microscopy and current-voltage characteristics. A finite element method simulation explains the electric field and voltage variation profile during DEP process. The optimized aligned GO nanostructures are used as hydrogen gas sensor with a sensitivity of 6.0% for 800 ppm hydrogen gas.

  13. Alignment of graphene oxide nanostructures between microgap electrodes via dielectrophoresis for hydrogen gas sensing applications

    NASA Astrophysics Data System (ADS)

    Singh, Budhi; Wang, Jianwei; Rathi, Servin; Kim, Gil-Ho

    2015-05-01

    Graphene oxide (GO) nanostructures have been aligned between conducting electrodes via dielectrophoresis (DEP) with different electrical configurations. The arrangement of ground with respect to peak-to-peak voltage (Vpp) plays a crucial role in manipulating the GO nanostructures. Grounds on both sides of the Vpp electrode give an excellent linking of GO nanostructures which is explained by scanning electron microscopy and current-voltage characteristics. A finite element method simulation explains the electric field and voltage variation profile during DEP process. The optimized aligned GO nanostructures are used as hydrogen gas sensor with a sensitivity of 6.0% for 800 ppm hydrogen gas.

  14. Method for the purification of noble gases, nitrogen and hydrogen

    DOEpatents

    Baker, J.D.; Meikrantz, D.H.; Tuggle, D.G.

    1997-09-23

    A method and apparatus are disclosed for the purification and collection of hydrogen isotopes in a flowing inert gaseous mixture containing impurities, wherein metal alloy getters having the capability of sorbing non-hydrogen impurities such as oxygen, carbon dioxide, carbon monoxide, methane, ammonia, nitrogen and water vapor are utilized to purify the gaseous mixture of impurities. After purification hydrogen isotopes may be more efficiently collected. A plurality of parallel process lines utilizing metal getter alloys can be used to provide for the continuous purification and collection of the hydrogen isotopes. 15 figs.

  15. Method for the purification of noble gases, nitrogen and hydrogen

    DOEpatents

    Baker, John D.; Meikrantz, David H.; Tuggle, Dale G.

    1997-01-01

    A method and apparatus for the purification and collection of hydrogen isotopes in a flowing inert gaseous mixture containing impurities, wherein metal alloy getters having the capability of sorbing non-hydrogen impurities such as oxygen, carbon dioxide, carbon monoxide, methane, ammonia, nitrogen and water vapor are utilized to purify the gaseous mixture of impurities. After purification hydrogen isotopes may be more efficiently collected. A plurality of parallel process lines utilizing metal getter alloys can be used to provide for the continuous purification and collection of the hydrogen isotopes.

  16. Measurement of Concentration Distribution of Hydrogen Gas Flow by Measuring the Intensity of Raman Scattering Light

    NASA Astrophysics Data System (ADS)

    Asahi, Ippei; Ninomiya, Hideki

    An experimental study to visualize and measure the concentration distribution of hydrogen gas flow using the Raman scattering was performed. A Nd:YAG laser of wavelength at 355 nm was used, and the beam pattern was transformed into a rectangle and a sheet beam was formed. The Raman scattered light was observed at a right angle with respect to the laser beam axis using a gated ICCD camera and an interference filter. Shadowgraph images were obtained at the same condition. The Raman scattering light image from atmospheric nitrogen was first acquired and the function of Raman scattering light acquisition and the background light suppression was confirmed. Next, images of the Raman scattering light image and shadowgraph of hydrogen gas discharged from a nozzle into the atmosphere were acquired. The two obtained Raman images were compared and the spatial concentration distribution of the flow of the hydrogen gas at different flow rates was calculated. This method is effective for visualizing the gas flow and measuring the concentration distribution of the Raman active molecules, such as hydrogen gas.

  17. Fundamental studies on kinetic isotope effect (KIE) of hydrogen isotope fractionation in natural gas systems

    USGS Publications Warehouse

    Ni, Y.; Ma, Q.; Ellis, G.S.; Dai, J.; Katz, B.; Zhang, S.; Tang, Y.

    2011-01-01

    Based on quantum chemistry calculations for normal octane homolytic cracking, a kinetic hydrogen isotope fractionation model for methane, ethane, and propane formation is proposed. The activation energy differences between D-substitute and non-substituted methane, ethane, and propane are 318.6, 281.7, and 280.2cal/mol, respectively. In order to determine the effect of the entropy contribution for hydrogen isotopic substitution, a transition state for ethane bond rupture was determined based on density function theory (DFT) calculations. The kinetic isotope effect (KIE) associated with bond rupture in D and H substituted ethane results in a frequency factor ratio of 1.07. Based on the proposed mathematical model of hydrogen isotope fractionation, one can potentially quantify natural gas thermal maturity from measured hydrogen isotope values. Calculated gas maturity values determined by the proposed mathematical model using ??D values in ethane from several basins in the world are in close agreement with similar predictions based on the ??13C composition of ethane. However, gas maturity values calculated from field data of methane and propane using both hydrogen and carbon kinetic isotopic models do not agree as closely. It is possible that ??D values in methane may be affected by microbial mixing and that propane values might be more susceptible to hydrogen exchange with water or to analytical errors. Although the model used in this study is quite preliminary, the results demonstrate that kinetic isotope fractionation effects in hydrogen may be useful in quantitative models of natural gas generation, and that ??D values in ethane might be more suitable for modeling than comparable values in methane and propane. ?? 2011 Elsevier Ltd.

  18. Hydrogen Energy Storage and Power-to-Gas: Establishing Criteria for Successful Business Cases

    SciTech Connect

    Eichman, Joshua; Melaina, Marc

    2015-10-27

    As the electric sector evolves and increasing amounts of variable generation are installed on the system, there are greater needs for system flexibility, sufficient capacity and greater concern for overgeneration. As a result there is growing interest in exploring the role of energy storage and demand response technologies to support grid needs. Hydrogen is a versatile feedstock that can be used in a variety of applications including chemical and industrial processes, as well as a transportation fuel and heating fuel. Traditionally, hydrogen technologies focus on providing services to a single sector; however, participating in multiple sectors has the potential to provide benefits to each sector and increase the revenue for hydrogen technologies. The goal of this work is to explore promising system configurations for hydrogen systems and the conditions that will make for successful business cases in a renewable, low-carbon future. Current electricity market data, electric and gas infrastructure data and credit and incentive information are used to perform a techno-economic analysis to identify promising criteria and locations for successful hydrogen energy storage and power-to-gas projects. Infrastructure data will be assessed using geographic information system applications. An operation optimization model is used to co-optimizes participation in energy and ancillary service markets as well as the sale of hydrogen. From previous work we recognize the great opportunity that energy storage and power-to-gas but there is a lack of information about the economic favorability of such systems. This work explores criteria for selecting locations and compares the system cost and potential revenue to establish competitiveness for a variety of equipment configurations. Hydrogen technologies offer unique system flexibility that can enable interactions between multiple energy sectors including electric, transport, heating fuel and industrial. Previous research established that

  19. Method for converting hydrocarbon fuel into hydrogen gas and carbon dioxide

    DOEpatents

    Clawson, Lawrence G.; Mitchell, William L.; Bentley, Jeffrey M.; Thijssen, Johannes H. J.

    2000-01-01

    A method for converting hydrocarbon fuel into hydrogen gas and carbon dioxide within a reformer 10 is disclosed. According to the method, a stream including an oxygen-containing gas is directed adjacent to a first vessel 18 and the oxygen-containing gas is heated. A stream including unburned fuel is introduced into the oxygen-containing gas stream to form a mixture including oxygen-containing gas and fuel. The mixture of oxygen-containing gas and unburned fuel is directed tangentially into a partial oxidation reaction zone 24 within the first vessel 18. The mixture of oxygen-containing gas and fuel is further directed through the partial oxidation reaction zone 24 to produce a heated reformate stream including hydrogen gas and carbon monoxide. Steam may also be mixed with the oxygen-containing gas and fuel, and the reformate stream from the partial oxidation reaction zone 24 directed into a steam reforming zone 26. High- and low-temperature shift reaction zones 64,76 may be employed for further fuel processing.

  20. 40 CFR 266.107 - Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Standards to control hydrogen chloride... Industrial Furnaces § 266.107 Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions. (a) General. The owner or operator must comply with the hydrogen chloride (HCl) and chlorine...

  1. 40 CFR 266.107 - Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 27 2014-07-01 2014-07-01 false Standards to control hydrogen chloride... Industrial Furnaces § 266.107 Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions. (a) General. The owner or operator must comply with the hydrogen chloride (HCl) and chlorine...

  2. 40 CFR 266.107 - Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 27 2011-07-01 2011-07-01 false Standards to control hydrogen chloride... Industrial Furnaces § 266.107 Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions. (a) General. The owner or operator must comply with the hydrogen chloride (HCl) and chlorine...

  3. 40 CFR 266.107 - Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 28 2012-07-01 2012-07-01 false Standards to control hydrogen chloride... Industrial Furnaces § 266.107 Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions. (a) General. The owner or operator must comply with the hydrogen chloride (HCl) and chlorine...

  4. 40 CFR 266.107 - Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 28 2013-07-01 2013-07-01 false Standards to control hydrogen chloride... Industrial Furnaces § 266.107 Standards to control hydrogen chloride (HCl) and chlorine gas (Cl2) emissions. (a) General. The owner or operator must comply with the hydrogen chloride (HCl) and chlorine...

  5. A hydrogen gas-water equilibration method produces accurate and precise stable hydrogen isotope ratio measurements in nutrition studies.

    PubMed

    Wong, William W; Clarke, Lucinda L

    2012-11-01

    Stable hydrogen isotope methodology is used in nutrition studies to measure growth, breast milk intake, and energy requirement. Isotope ratio MS is the best instrumentation to measure the stable hydrogen isotope ratios in physiological fluids. Conventional methods to convert physiological fluids to hydrogen gas (H(2)) for mass spectrometric analysis are labor intensive, require special reagent, and involve memory effect and potential isotope fractionation. The objective of this study was to determine the accuracy and precision of a platinum catalyzed H(2)-water equilibration method for stable hydrogen isotope ratio measurements. Time to reach isotopic equilibrium, day-to-day and week-to-week reproducibility, accuracy, and precision of stable hydrogen isotope ratio measurements by the H(2)-water equilibration method were assessed using a Thermo DELTA V Advantage continuous-flow isotope ratio mass spectrometer. It took 3 h to reach isotopic equilibrium. The day-to-day and week-to-week measurements on water and urine samples with natural abundance and enriched levels of deuterium were highly reproducible. The method was accurate to within 2.8 (o)/oo and reproducible to within 4.0 (o)/oo based on analysis of international references. All the outcome variables, whether in urine samples collected in 10 doubly labeled water studies or plasma samples collected in 26 body water studies, did not differ from those obtained using the reference zinc reduction method. The method produced highly accurate estimation on ad libitum energy intakes, body composition, and water turnover rates. The method greatly reduces the analytical cost and could easily be adopted by laboratories equipped with a continuous-flow isotope ratio mass spectrometer.

  6. A Hydrogen Gas-Water Equilibration Method Produces Accurate and Precise Stable Hydrogen Isotope Ratio Measurements in Nutrition Studies12

    PubMed Central

    Wong, William W.; Clarke, Lucinda L.

    2012-01-01

    Stable hydrogen isotope methodology is used in nutrition studies to measure growth, breast milk intake, and energy requirement. Isotope ratio MS is the best instrumentation to measure the stable hydrogen isotope ratios in physiological fluids. Conventional methods to convert physiological fluids to hydrogen gas (H2) for mass spectrometric analysis are labor intensive, require special reagent, and involve memory effect and potential isotope fractionation. The objective of this study was to determine the accuracy and precision of a platinum catalyzed H2-water equilibration method for stable hydrogen isotope ratio measurements. Time to reach isotopic equilibrium, day-to-day and week-to-week reproducibility, accuracy, and precision of stable hydrogen isotope ratio measurements by the H2-water equilibration method were assessed using a Thermo DELTA V Advantage continuous-flow isotope ratio mass spectrometer. It took 3 h to reach isotopic equilibrium. The day-to-day and week-to-week measurements on water and urine samples with natural abundance and enriched levels of deuterium were highly reproducible. The method was accurate to within 2.8 o/oo and reproducible to within 4.0 o/oo based on analysis of international references. All the outcome variables, whether in urine samples collected in 10 doubly labeled water studies or plasma samples collected in 26 body water studies, did not differ from those obtained using the reference zinc reduction method. The method produced highly accurate estimation on ad libitum energy intakes, body composition, and water turnover rates. The method greatly reduces the analytical cost and could easily be adopted by laboratories equipped with a continuous-flow isotope ratio mass spectrometer. PMID:23014490

  7. Enhancement of hydrogen gas sensing of nanocrystalline nickel oxide by pulsed-laser irradiation.

    PubMed

    Soleimanpour, A M; Khare, Sanjay V; Jayatissa, Ahalapitiya H

    2012-09-26

    This paper reports the effect of post-laser irradiation on the gas-sensing behavior of nickel oxide (NiO) thin films. Nanocrystalline NiO semiconductor thin films were fabricated by a sol-gel method on a nonalkaline glass substrate. The NiO samples were irradiated with a pulsed 532-nm wavelength, using a Nd:YVO(4) laser beam. The effect of laser irradiation on the microstructure, electrical conductivity, and gas-sensing properties was investigated as a function of laser power levels. It was found that the crystallinity and surface morphology were modified by the pulsed-laser irradiation. Hydrogen gas sensors were fabricated using both as-deposited and laser-irradiated NiO films. It was observed that the performance of gas-sensing characteristics could be changed by the change of laser power levels. By optimizing the magnitude of the laser power, the gas-sensing property of NiO thin film was improved, compared to that of as-deposited NiO films. At the optimal laser irradiation conditions, a high response of NiO sensors to hydrogen molecule exposure of as little as 2.5% of the lower explosion threshold of hydrogen gas (40,000 ppm) was observed at 175 °C.

  8. The hydrogen gas clearance method for liver blood flow examination: inhalation or local application of hydrogen?

    PubMed

    Metzger, H P

    1989-01-01

    The combined method of hydrogen inhalation and local hydrogen production enable the determination of hepatic blood flow (HBF) and local hepatic blood flow (LHBF). LHBF was registered within a small superficial tissue volume of 0.5 mm in diameter by means of a multi-wire electrode having 200 microns producing and 100 microns measuring wires arranged within less than 300 microns distance between the measuring wires. The feeding current for hydrogen production was 1 microA, the potential less than 10 V. The clearance in response to inhalation was registered by means of the same measuring electrodes within the same tissue volume. Spontaneously breathing rats (Wistar-Frömter strain, 180-230 g bw, N = 19, ketamin-xylazine anesthesia, artificial respiration) showed the following flow values: HBF +/- SD = 0.50 +/- 0.26 ml/g.min, n = 48 registrations; LHBF +/- SD = 4.66 +/- 2.13 ml/g.min, n = 43. The validity of the combined method is demonstrated in the LHBF/HBF graph which summarizes the data of hemorrhagic and control animals, m = 0.1 and yo = 0.001. The correlation coefficient of r = 0.685 shows a reasonable correlation of the combined data despite the wide scattering of the individual values.

  9. Validation of hydrogen gas stratification and mixing models

    DOE PAGES

    Wu, Hsingtzu; Zhao, Haihua

    2015-05-26

    Two validation benchmarks confirm that the BMIX++ code is capable of simulating unintended hydrogen release scenarios efficiently. The BMIX++ (UC Berkeley mechanistic MIXing code in C++) code has been developed to accurately and efficiently predict the fluid mixture distribution and heat transfer in large stratified enclosures for accident analyses and design optimizations. The BMIX++ code uses a scaling based one-dimensional method to achieve large reduction in computational effort compared to a 3-D computational fluid dynamics (CFD) simulation. Two BMIX++ benchmark models have been developed. One is for a single buoyant jet in an open space and another is for amore » large sealed enclosure with both a jet source and a vent near the floor. Both of them have been validated by comparisons with experimental data. Excellent agreements are observed. The entrainment coefficients of 0.09 and 0.08 are found to fit the experimental data for hydrogen leaks with the Froude number of 99 and 268 best, respectively. In addition, the BIX++ simulation results of the average helium concentration for an enclosure with a vent and a single jet agree with the experimental data within a margin of about 10% for jet flow rates ranging from 1.21 × 10⁻⁴ to 3.29 × 10⁻⁴ m³/s. In conclusion, computing time for each BMIX++ model with a normal desktop computer is less than 5 min.« less

  10. Validation of hydrogen gas stratification and mixing models

    SciTech Connect

    Wu, Hsingtzu; Zhao, Haihua

    2015-05-26

    Two validation benchmarks confirm that the BMIX++ code is capable of simulating unintended hydrogen release scenarios efficiently. The BMIX++ (UC Berkeley mechanistic MIXing code in C++) code has been developed to accurately and efficiently predict the fluid mixture distribution and heat transfer in large stratified enclosures for accident analyses and design optimizations. The BMIX++ code uses a scaling based one-dimensional method to achieve large reduction in computational effort compared to a 3-D computational fluid dynamics (CFD) simulation. Two BMIX++ benchmark models have been developed. One is for a single buoyant jet in an open space and another is for a large sealed enclosure with both a jet source and a vent near the floor. Both of them have been validated by comparisons with experimental data. Excellent agreements are observed. The entrainment coefficients of 0.09 and 0.08 are found to fit the experimental data for hydrogen leaks with the Froude number of 99 and 268 best, respectively. In addition, the BIX++ simulation results of the average helium concentration for an enclosure with a vent and a single jet agree with the experimental data within a margin of about 10% for jet flow rates ranging from 1.21 × 10⁻⁴ to 3.29 × 10⁻⁴ m³/s. In conclusion, computing time for each BMIX++ model with a normal desktop computer is less than 5 min.

  11. 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.

  12. Decreases in deuterium pumping by St707 getter alloy caused by carbon dioxide preexposure

    SciTech Connect

    Malinowski, M.E.

    1985-05-01

    Intentional passivation of the deuterium pumping of the solid getter alloy St707 has been attempted by exposing samples of St707 to carbon dioxide at different pressures, temperatures and exposure times relevant for application to the getter modules in the ALT-I pump limiter. It was found that one of the most effective treatments examined was a 30 min, 1 Torr exposure at approximately 100 /sup 0/C. This preexposure kept the getter pumping speed less than 0.001 of its rated value for about 3 min when exposed to deuterium at 1 Torr and 30 /sup 0/C. After this ''incubation'' period, the getter speed increases to values greater than approx.1% of fully activated values. If left under high deuterium pressure, the getter eventually flakes off the substrate. Video observations of the flaking process indicate that individual particles leave the constantan getter substrate at velocities of 1 m/s. Attempts at passivating the getter using oxygen and carbon monoxide were found to be no more effective than using carbon dioxide, suggesting that there is no way to completely passivate the getter with these gases at pressures low enough for application to in situ getter arrays used in tokamaks.

  13. Hydrogen production and delivery analysis in US markets : cost, energy and greenhouse gas emissions.

    SciTech Connect

    Mintz, M.; Gillette, J.; Elgowainy, A.

    2009-01-01

    Hydrogen production cost conclusions are: (1) Steam Methane Reforming (SMR) is the least-cost production option at current natural gas prices and for initial hydrogen vehicle penetration rates, at high production rates, SMR may not be the least-cost option; (2) Unlike coal and nuclear technologies, the cost of natural gas feedstock is the largest contributor to SMR production cost; (3) Coal- and nuclear-based hydrogen production have significant penalties at small production rates (and benefits at large rates); (4) Nuclear production of hydrogen is likely to have large economies of scale, but because fixed O&M costs are uncertain, the magnitude of these effects may be understated; and (5) Given H2A default assumptions for fuel prices, process efficiencies and labor costs, nuclear-based hydrogen is likely to be more expensive to produce than coal-based hydrogen. Carbon taxes and caps can narrow the gap. Hydrogen delivery cost conclusions are: (1) For smaller urban markets, compressed gas delivery appears most economic, although cost inputs for high-pressure gas trucks are uncertain; (2) For larger urban markets, pipeline delivery is least costly; (3) Distance from hydrogen production plant to city gate may change relative costs (all results shown assume 100 km); (4) Pipeline costs may be reduced with system 'rationalization', primarily reductions in service pipeline mileage; and (5) Liquefier and pipeline capital costs are a hurdle, particularly at small market sizes. Some energy and greenhouse gas Observations: (1) Energy use (per kg of H2) declines slightly with increasing production or delivery rate for most components (unless energy efficiency varies appreciably with scale, e.g., liquefaction); (2) Energy use is a strong function of production technology and delivery mode; (3) GHG emissions reflect the energy efficiency and carbon content of each component in a production-delivery pathway; (4) Coal and natural gas production pathways have high energy consumption

  14. Generation of hydrogen rich gas through fluidized bed gasification of biomass.

    PubMed

    Karmakar, M K; Datta, A B

    2011-01-01

    The objective of this study was to investigate the process of generating hydrogen rich syngas through thermo chemical fluidized bed gasification of biomass. The experiments were performed in a laboratory scale externally heated biomass gasifier. Rice husk had been taken as a representative biomass and, steam had been used as the fluidizing and gasifying media. A thermodynamic equilibrium model was used to predict the gasification process. The work included the parametric study of process parameters such as reactor temperature and steam biomass ratio which generally influence the percentage of hydrogen content in the product gas. Steam had been used here to generate nitrogen free product gas and also to increase the hydrogen concentration in syngas with a medium range heating value of around 12 MJ/Nm3.

  15. Testing of a Hydrogen Diffusion Flame Array Injector at Gas Turbine Conditions

    SciTech Connect

    Weiland, Nathan T.; Sidwell, Todd G.; Strakey, Peter A.

    2013-07-03

    High-hydrogen gas turbines enable integration of carbon sequestration into coal-gasifying power plants, though NO{sub x} emissions are often high. This work explores nitrogen dilution of hydrogen diffusion flames to reduce thermal NO{sub x} emissions and avoid problems with premixing hydrogen at gas turbine pressures and temperatures. The burner design includes an array of high-velocity coaxial fuel and air injectors, which balances stability and ignition performance, combustor pressure drop, and flame residence time. Testing of this array injector at representative gas turbine conditions (16 atm and 1750 K firing temperature) yields 4.4 ppmv NO{sub x} at 15% O{sub 2} equivalent. NO{sub x} emissions are proportional to flame residence times, though these deviate from expected scaling due to active combustor cooling and merged flame behavior. The results demonstrate that nitrogen dilution in combination with high velocities can provide low NO{sub x} hydrogen combustion at gas turbine conditions, with significant potential for further NO{sub x} reductions via suggested design changes.

  16. ASU nitrogen sweep gas in hydrogen separation membrane for production of HRSG duct burner fuel

    SciTech Connect

    Panuccio, Gregory J.; Raybold, Troy M.; Jamal, Agil; Drnevich, Raymond Francis

    2013-04-02

    The present invention relates to the use of low pressure N2 from an air separation unit (ASU) for use as a sweep gas in a hydrogen transport membrane (HTM) to increase syngas H2 recovery and make a near-atmospheric pressure (less than or equal to about 25 psia) fuel for supplemental firing in the heat recovery steam generator (HRSG) duct burner.

  17. Rapid hydrogen gas generation using reactive thermal decomposition of uranium hydride.

    SciTech Connect

    Kanouff, Michael P.; Van Blarigan, Peter; Robinson, David B.; Shugard, Andrew D.; Gharagozloo, Patricia E.; Buffleben, George M.; James, Scott Carlton; Mills, Bernice E.

    2011-09-01

    Oxygen gas injection has been studied as one method for rapidly generating hydrogen gas from a uranium hydride storage system. Small scale reactors, 2.9 g UH{sub 3}, were used to study the process experimentally. Complimentary numerical simulations were used to better characterize and understand the strongly coupled chemical and thermal transport processes controlling hydrogen gas liberation. The results indicate that UH{sub 3} and O{sub 2} are sufficiently reactive to enable a well designed system to release gram quantities of hydrogen in {approx} 2 seconds over a broad temperature range. The major system-design challenge appears to be heat management. In addition to the oxidation tests, H/D isotope exchange experiments were performed. The rate limiting step in the overall gas-to-particle exchange process was found to be hydrogen diffusion in the {approx}0.5 {mu}m hydride particles. The experiments generated a set of high quality experimental data; from which effective intra-particle diffusion coefficients can be inferred.

  18. High-pressure gas facilitates calibration of turbine flowmeters for liquid hydrogen

    NASA Technical Reports Server (NTRS)

    Krause, L. N.; Szaniszlo, A. J.

    1968-01-01

    Nitrogen gas at a pressure of 60 atmospheres and ambient temperature facilitates the calibration of turbine flowmeters used for monitoring the flow of liquid hydrogen in cryogenic systems. Full-scale calibration factors can be obtained to an accuracy of 0.4 percent.

  19. NEAR-CONTINUOUS MEASUREMENT OF HYDROGEN SULFIDE AND CARBONYL SULFIDE BY AN AUTOMATIC GAS CHROMATOGRAPH

    EPA Science Inventory

    An automatic gas chromatograph with a flame photometric detector that samples and analyzes hydrogen sulfide and carbonyl sulfide at 30-s intervals is described. Temperature programming was used to elute trace amounts of carbon disulfide present in each injection from a Supelpak-S...

  20. Explosive composition with group VIII metal nitroso halide getter

    DOEpatents

    Walker, Franklin E.; Wasley, Richard J.

    1982-01-01

    An improved explosive composition is disclosed and comprises a major portion of an explosive having a detonation velocity between about 1,500 and 10,000 meters per second and a minor amount of a getter additive comprising a non-explosive compound or mixture of non-explosive compounds capable of chemically reacting with free radicals or ions under shock initiation conditions of 2,000 calories/cm.sup.2 or less of energy fluence.

  1. Explosive composition with group VIII metal nitroso halide getter

    DOEpatents

    Walker, F.E.; Wasley, R.J.

    1982-06-22

    An improved explosive composition is disclosed and comprises a major portion of an explosive having a detonation velocity between about 1,500 and 10,000 meters per second and a minor amount of a getter additive comprising a non-explosive compound or mixture of non-explosive compounds capable of chemically reacting with free radicals or ions under shock initiation conditions of 2,000 calories/cm[sup 2] or less of energy fluence.

  2. Distributed Non-evaporable Getter pumps for the storage ring of the APS

    SciTech Connect

    Dortwegt, R.; Benaroya, R.

    1993-07-01

    A pair of distributed Non-evaporable Getter (NeG) strip assemblies is installed in each of 236 aluminum vacuum chambers of the 1104-m storage ring of the Advanced Photon Source. Distributed pumping is provided to remove most of the gas resulting from photon-stimulated desorption occurring along the outer walls of the chambers. This is an efficient way of pumping because conductance is limited along the beam axis. The St-707 NeG strips are conditioned at 450{degree}C for 45 min. with 42 A. Base pressures obtained are also as low as 4 {times} 10{sup 11} Torr. The NeG strip assemblies are supported by a series of electrically isolated, 125-mm-long, interlocking stainless steel carriers. These unique interlocking carrier elements provide flexibility along the vacuum chamber curvature (r=38.96 m) and permit removal and installation of assemblies with as little as 150 mm external clearance between adjacent chambers.

  3. Influence of hydrogen patterning gas on electric and magnetic properties of perpendicular magnetic tunnel junctions

    SciTech Connect

    Jeong, J. H.; Endoh, T.; Kim, Y.; Kim, W. K.; Park, S. O.

    2014-05-07

    To identify the degradation mechanism in magnetic tunnel junctions (MTJs) using hydrogen, the properties of the MTJs were measured by applying an additional hydrogen etch process and a hydrogen plasma process to the patterned MTJs. In these studies, an additional 50 s hydrogen etch process caused the magnetoresistance (MR) to decrease from 103% to 14.7% and the resistance (R) to increase from 6.5 kΩ to 39 kΩ. Moreover, an additional 500 s hydrogen plasma process decreased the MR from 103% to 74% and increased R from 6.5 kΩ to 13.9 kΩ. These results show that MTJs can be damaged by the hydrogen plasma process as well as by the hydrogen etch process, as the atomic bonds in MgO may break and react with the exposed hydrogen gas. Compounds such as MgO hydrate very easily. We also calculated the damaged layer width (DLW) of the patterned MTJs after the hydrogen etching and plasma processes, to evaluate the downscaling limitations of spin-transfer-torque magnetic random-access memory (STT-MRAM) devices. With these calculations, the maximum DLWs at each side of the MTJ, generated by the etching and plasma processes, were 23.8 nm and 12.8 nm, respectively. This result validates that the hydrogen-based MTJ patterning processes cannot be used exclusively in STT-MRAMs beyond 20 nm.

  4. Rate limiting mechanism of transition metal gettering in multicrystalline silicon

    SciTech Connect

    McHugo, S.A.; Thompson, A.C.; Imaizumi, M.; Hieslmair, H.; Weberr, E.R.

    1997-07-01

    The authors have performed studies on multicrystalline silicon used for solar cells in the as-grown state and after a series of processing and gettering steps. The principal goal of this work is to determine the rate limiting step for metal impurity gettering from multicrystalline silicon with an emphasis on the release of impurities from structural defects. Synchrotron-based x-ray fluorescence mapping was used to monitor the release process. Copper and nickel impurities were found to reside primarily at dislocations in the as-grown state of the material. Short annealing treatments rapidly dissolved the impurity agglomerates. Based on these results and modeling of the dissolution process, copper and nickel is in the form of small agglomerates (< 10 nm) clustered together over micron-scale regions in the as-grown material. Aluminum gettering further disintegrated the agglomerates to below the sensitivity of the system, 2--5 nm in radii. No significant barrier to release of copper or nickel from dislocations was observed.

  5. Gas Reactor Plant Analyzer and Simulator for Hydrogen Production

    2004-01-01

    This software is used to study and analyze various configurations of plant equipment for gas cooled nuclear reactor applications. The user of this software would likely be interested in optimizing the economic, safety, and operating performance of this type of reactor. The code provides the capability for the user through his input to configure networks of nuclear reactor components. The components available include turbine, compressor, heat exchanger, reactor core, coolers, bypass valves, and control systems.

  6. Hydrogen gas sensor based on metal oxide nanoparticles decorated graphene transistor

    NASA Astrophysics Data System (ADS)

    Zhang, Zhangyuan; Zou, Xuming; Xu, Lei; Liao, Lei; Liu, Wei; Ho, Johnny; Xiao, Xiangheng; Jiang, Changzhong; Li, Jinchai

    2015-05-01

    In this work, in order to enhance the performance of graphene gas sensors, graphene and metal oxide nanoparticles (NPs) are combined to be utilized for high selectivity and fast response gas detection. Whether at the relatively optimal temperature or even room temperature, our gas sensors based on graphene transistors, decorated with SnO2 NPs, exhibit fast response and short recovery times (~1 seconds) at 50 °C when the hydrogen concentration is 100 ppm. Specifically, X-ray photoelectron spectroscopy and conductive atomic force microscopy are employed to explore the interface properties between graphene and SnO2 NPs. Through the complimentary characterization, a mechanism based on charge transfer and band alignment is elucidated to explain the physical originality of these graphene gas sensors: high carrier mobility of graphene and small energy barrier between graphene and SnO2 NPs have ensured a fast response and a high sensitivity and selectivity of the devices. Generally, these gas sensors will facilitate the rapid development of next-generation hydrogen gas detection.In this work, in order to enhance the performance of graphene gas sensors, graphene and metal oxide nanoparticles (NPs) are combined to be utilized for high selectivity and fast response gas detection. Whether at the relatively optimal temperature or even room temperature, our gas sensors based on graphene transistors, decorated with SnO2 NPs, exhibit fast response and short recovery times (~1 seconds) at 50 °C when the hydrogen concentration is 100 ppm. Specifically, X-ray photoelectron spectroscopy and conductive atomic force microscopy are employed to explore the interface properties between graphene and SnO2 NPs. Through the complimentary characterization, a mechanism based on charge transfer and band alignment is elucidated to explain the physical originality of these graphene gas sensors: high carrier mobility of graphene and small energy barrier between graphene and SnO2 NPs have ensured a

  7. High-response on-line gas analysis system for hydrogen-reaction combustion products

    NASA Technical Reports Server (NTRS)

    Metzler, A. J.; Gaugler, R. E.

    1974-01-01

    The results of testing an on-line quadrupole gas analyzer system are reported. Gas samples were drawn from the exhaust of a hydrogen-oxygen-nitrogen rocket which simulated the flow composition and dynamics at the combustor exit of a supersonic combustion ramjet engine. System response time of less than 50 milliseconds was demonstrated, with analytical accuracy estimated to be + or - 5 percent. For more complex chemical systems with interfering atom patterns, analysis would be more difficult. A cooled-gas pyrometer probe was evaluated as a total temperature indicator and as the primary mass flow measuring element for the total sample flow rate.

  8. Alternating Current Dielectrophoresis Optimization of Pt-Decorated Graphene Oxide Nanostructures for Proficient Hydrogen Gas Sensor.

    PubMed

    Wang, Jianwei; Rathi, Servin; Singh, Budhi; Lee, Inyeal; Joh, Han-Ik; Kim, Gil-Ho

    2015-07-01

    Alternating current dielectrophoresis (DEP) is an excellent technique to assemble nanoscale materials. For efficient DEP, the optimization of the key parameters like peak-to-peak voltage, applied frequency, and processing time is required for good device. In this work, we have assembled graphene oxide (GO) nanostructures mixed with platinum (Pt) nanoparticles between the micro gap electrodes for a proficient hydrogen gas sensors. The Pt-decorated GO nanostructures were well located between a pair of prepatterned Ti/Au electrodes by controlling the DEP technique with the optimized parameters and subsequently thermally reduced before sensing. The device fabricated using the DEP technique with the optimized parameters showed relatively high sensitivity (∼10%) to 200 ppm hydrogen gas at room temperature. The results indicates that the device could be used in several industry applications, such as gas storage and leak detection. PMID:26042360

  9. Gas-phase hydrogenation/hydrogenolysis of phenol over supported nickel catalysts

    SciTech Connect

    Shin, E.J.; Keane, M.A.

    2000-04-01

    The gas-phase hydrogenation/hydrogenolysis of alcoholic solutions of phenol between 423 and 573 K has been studied using a Y zeolite-supported nickel catalyst (2.2% w/w Ni) and Ni/SiO{sub 2} catalysts (1.5--20.3% w/w Ni). This is a viable means of treating concentrated phenol streams to generate recyclable raw material. Phenol hydrogenation proceeded in a stepwise fashion with cyclohexanone as a reactive intermediate while a combination of hydrogenolysis and hydrogenation yielded cyclohexane. Hydrogenolysis to benzene is favored by high nickel loadings and elevated temperatures. A catalytic hydrogen treatment of cyclohexanone and cyclohexanol helped to establish the overall reaction network/mechanism. The possible role of thermodynamic limitations is considered and structure sensitivity is addressed; reaction data are subjected to a pseudo-first-order kinetic treatment. Hydrogen temperature-programmed desorption (H{sub 2}-TPD) has revealed the existence of different forms of surface hydrogen. Selectivity is interpreted on the basis of the H{sub 2}-TPD profiles and the possible phenol/catalyst interactions. The zeolite sample only catalyzed (via the surface Bronsted acidity) anisole formation in the presence of methanol, but this was suppressed when hexanol was used; the zeolite then promoted hydrogenolysis. The zeolite, however, deactivated and this was not reversed by heating in hydrogen. The results of the hydrogen treatment of aqueous rather than alcoholic phenol solutions are presented, where a switch from methanol to water was accompanied by a move from highly selective hydrogenolysis to highly selective hydrogenation.

  10. Inhalation of hydrogen gas reduces liver injury during major hepatotectomy in swine

    PubMed Central

    Xiang, Lei; Tan, Jing-Wang; Huang, Li-Jie; Jia, Lin; Liu, Ya-Qian; Zhao, Yu-Qiong; Wang, Kai; Dong, Jia-Hong

    2012-01-01

    AIM: To study the effect of H2 gas on liver injury in massive hepatectomy using the Intermittent Pringle maneuver in swine. METHODS: Male Bama pigs (n = 14) treated with ketamine hydrochloride and Sumianxin II as induction drugs followed by inhalation anesthesia with 2% isoflurane, underwent 70% hepatotectomy with loss of bleeding less than 50 mL, and with hepatic pedicle occlusion for 20 min, were divided into two groups: Hydrogen-group (n = 7), the pigs with inhalation of 2% hydrogen by the tracheal intubation during major hepatotectomy; Contrast-group (n = 7), underwent 70% hepatotectomy without inhalation of hydrogen. Hemodynamic changes and plasma concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronic acid (HA), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and malondialdehyde (MDA) in liver tissue were measured at pre-operation, post-hepatotectomy (PH) 1 h and 3 h. The apoptosis and proliferating cell nuclear antigen (PCNA) expression in liver remnant were evaluated at PH 3 h. Then we compared the two groups by these marks to evaluate the effect of the hydrogen in the liver injury during major hepatotectomy with the Pringle Maneuver in the swine. RESULTS: There were no significant differences in body weight, blood loss and removal liver weight between the two groups. There was no significant difference in changes of portal vein pressure between two groups at pre-operation, PH 30 min, but in hydrogen gas treated-group it slightly decrease and lower than its in Contrast-group at PH 3 h, although there were no significant difference (P = 0.655). ALT and AST in Hydrogen-group was significantly lower comparing to Contrast-group (P = 0.036, P = 0.011, vs P = 0.032, P = 0.013) at PH 1 h and 3 h, although the two groups all increased. The MDA level increased between the two group at PH 1 h and 3 h. In the hydrogen gas treated-group, the MDA level was not significantly significant at pre-operation and significantly

  11. Quantitative hydrogen analysis of zircaloy-4 in laser-induced breakdown spectroscopy with ambient helium gas

    SciTech Connect

    Ramli, Muliadi; Fukumoto, Ken-ichi; Niki, Hideaki; Abdulmadjid, Syahrun Nur; Idris, Nasrullah; Maruyama, Tadashi; Kagawa, Kiichiro; Tjia, May On; Pardede, Marincan; Kurniawan, Koo Hendrik; Hedwig, Rinda; Lie, Zener Sukra; Lie, Tjung Jie; Kurniawan, Davy Putra

    2007-12-01

    This experiment was carried out to address the need for overcoming the difficulties encountered in hydrogen analysis by means of plasma emission spectroscopy in atmospheric ambient gas. The result of this study on zircaloy-4 samples from a nuclear power plant demonstrates the possibility of attaining a very sharp emission line from impure hydrogen with a very low background and practical elimination of spectral contamination of hydrogen emission arising from surface water and water vapor in atmospheric ambient gas. This was achieved by employing ultrapure ambient helium gas as well as the proper defocusing of the laser irradiation and a large number of repeated precleaning laser shots at the same spot of the sample surface. Further adjustment of the gating time has led to significant reduction of spectral width and improvement of detection sensitivity to {approx}50 ppm. Finally, a linear calibration curve was also obtained for the zircaloy-4 samples with zero intercept. These results demonstrate the feasibility of this technique for practical in situ and quantitative analysis of hydrogen impurity in zircaloy-4 tubes used in a light water nuclear power plant.

  12. Direct Chlorination Process for geothermal power plant off-gas - hydrogen sulfide abatement

    SciTech Connect

    Sims, A.V.

    1983-06-01

    The Direct Chlorination Process removes hydrogen sulfide from geothermal off-gases by reacting hydrogen sulfide with chlorine in the gas phase. Hydrogen chloride and elemental sulfur are formed by this reaction. The Direct Chlorination Process has been successfully demonstrated by an on-site operation of a pilot plant at the 3 M We HPG-A geothermal power plant in the Puna District on the island of Hawaii. Over 99.5% hydrogen sulfide removal was achieved in a single reaction stage. Chlorine gas did not escape the pilot plant, even when 90% excess chlorine gas was used. A preliminary economic evaluation of the Direct Chlorination Process indicates that it is very competitive with the Stretford Process Compared to the Stretford Process, the Direct Chlorination process requires about one-third the initial capital investment and about one-fourth the net daily expenditure. Because of the higher cost of chemicals and the restricted markets in Hawaii, the economic viability of this process in Hawaii is questionable.

  13. National Combustion Code Used To Study the Hydrogen Injector Design for Gas Turbines

    NASA Technical Reports Server (NTRS)

    Iannetti, Anthony C.; Norris, Andrew T.; Shih, Tsan-Hsing

    2005-01-01

    Hydrogen, in the gas state, has been proposed to replace Jet-A (the fuel used for commercial jet engines) as a fuel for gas turbine combustion. For the combustion of hydrogen and oxygen only, water is the only product and the main greenhouse gas, carbon dioxide, is not produced. This is an obvious benefit of using hydrogen as a fuel. The situation is not as simple when air replaces oxygen in the combustion process. (Air is mainly a mixture of oxygen, nitrogen, and argon. Other components comprise a very small part of air and will not be mentioned.) At the high temperatures found in the combustion process, oxygen reacts with nitrogen, and this produces nitrogen oxide compounds, or NOx--the main component of atmospheric smog. The production of NOx depends mainly on two variables: the temperature at which combustion occurs, and the length of time that the products of combustion stay, or reside, in the combustor. Starting from a lean (excess air) air-to-fuel ratio, the goal of this research was to minimize hot zones caused by incomplete premixing and to keep the residence time short while producing a stable flame. The minimization of these two parameters will result in low- NOx hydrogen combustion.

  14. Effects of a Hydrogen Gas Environment on Fatigue Crack Growth of a Stable Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Kawamoto, Kyohei; Oda, Yasuji; Noguchi, Hiroshi; Higashida, Kenji

    In order to clarify the effects of a hydrogen gas environment on the fatigue crack growth characteristics of stable austenitic stainless steels, bending fatigue tests were carried out in a hydrogen gas, in a nitrogen gas at 1.0 MPa and in air on a SUS316L using the Japanese Industrial Standards (type 316L). Also, in order to discuss the difference in the hydrogen sensitivity between austenitic stainless steels, the fatigue tests were also carried out on a SUS304 using the Japanese Industrial Standards (type 304) metastable austenitic stainless steel as a material for comparison. The main results obtained are as follows. Hydrogen gas accelerates the fatigue crack growth rate of type 316L. The degree of the fatigue crack growth acceleration is low compared to that in type 304. The fracture surfaces of both the materials practically consist of two parts; the faceted area seemed to be brittle and the remaining area occupying a greater part of the fracture surface and seemed to be ductile. The faceted area does not significantly contribute to the fatigue crack growth rate in both austenitic stainless steels. The slip-off mechanism seems to be valid not only in air and in nitrogen, but also in hydrogen. Also, the main cause of the fatigue crack growth acceleration of both materials occurs by variation of the slip behaviour. The difference in the degree of the acceleration, which in type 316L is lower than in type 304, seems to be caused by the difference in the stability of the γ phase.

  15. EFFECT OF MINOR ADDITIONS OF HYDROGEN TO ARGON SHIELDING GAS WHEN WELDING AUSTENITIC STAINLESS STEEL WITH THE GTAW PROCESS

    SciTech Connect

    CANNELL, G.R.

    2004-12-15

    This paper provides the technical basis to conclude that the use of hydrogen containing shielding gases during welding of austenitic stainless steels will not lead to hydrogen induced cracking (HIC) of the weld or weld heat affected zone. Argon-hydrogen gas mixtures, with hydrogen additions up to 35% [1], have been successfully used as the shielding gas in gas tungsten arc welding (GTAW) of austenitic stainless steels. The addition of hydrogen improves weld pool wettability, bead shape control, surface cleanliness and heat input. The GTAW process is used extensively for welding various grades of stainless steel and is preferred when a very high weld quality is desired, such as that required for closure welding of nuclear materials packages. The use of argon-hydrogen gas mixtures for high-quality welding is occasionally questioned, primarily because of concern over the potential for HIC. This paper was written specifically to provide a technical basis for using an argon-hydrogen shielding gas in conjunction with the development, at the Savannah River Technology Center (SRTC), of an ''optimized'' closure welding process for the DOE standardized spent nuclear fuel canister [2]. However, the basis developed here can be applied to other applications in which the use of an argon-hydrogen shielding gas for GTAW welding of austenitic stainless steels is desired.

  16. Hydrogen-bonded glycine-HCN complexes in gas phase: structure, energetics, electric properties and cooperativity

    NASA Astrophysics Data System (ADS)

    Machado da Silva, Arnaldo; Chakrabarty, Sumana; Chaudhuri, Puspitapallab

    2015-03-01

    Twelve hydrogen-bonded complexes of glycine and hydrogen cyanide have been studied using high-level quantum-chemical calculations in gas phase. In particular, six 1:1 glycine-HCN dimers and six 1:2 glycine-HCN trimers have been considered. Besides the characteristics of the hydrogen bonds and their effect on molecular structure and energetics, several molecular electric properties have been calculated utilising two different models: MP2/6-31++G(d,p) and DFT-B3LYP/6-31++G(d,p). Although the structural parameters calculated by the two models are similar, equilibrium electronic energies of the clusters show model dependence. The lowest energy dimer is same in both the models which is ca. 3.0 kcal/mol more stable than the highest energy dimer. However, the lowest energy trimer is different in two methods. The energetic difference of stability between the highest and lowest trimer is 4.2 kcal/mol (4.4 kcal/mol) at an MP2 (B3LYP) level of calculation. The bond angles of glycine, in particular, are quite sensitive to the hydrogen-bond formation. Four out of six trimers are found to be strongly cooperative in both the models. Significant changes of dipole moments and polarisabilities of isolated glycine and hydrogen cyanide are observed due to the formation of hydrogen bonding. The Rayleigh scattering intensities of all clusters are much larger than those of their constituent monomers.

  17. Performance of a CVD grown graphene-based planar device for a hydrogen gas sensor

    NASA Astrophysics Data System (ADS)

    Dutta, D.; Hazra, A.; Hazra, S. K.; Das, J.; Bhattacharyya, S.; Sarkar, C. K.; Basu, S.

    2015-11-01

    A multilayer graphene (MLG) film was grown on thermally oxidized silicon (SiO2/Si) substrate by atmospheric pressure chemical vapor deposition (APCVD). The formation of the MLG and the presence of the oxide on the graphene surface were confirmed by Raman spectroscopy and electron dispersive spectroscopy (EDS), respectively. An energy gap of 0.234 eV was determined by the optical transmission method. The surface morphology of the graphene film was studied by field emission scanning electron microscopy (FESEM) and by atomic force microscopy (AFM). A planar device with lateral Pd metal contacts was used for the hydrogen sensor studies. The sensor performance in the temperature range (110 °C-150 °C) revealed a relatively fast response (~12 s) and recovery (~24 s) for hydrogen sensing. The reproducibility, the selectivity, and the stability of the device were also studied. The sensor was found to be selective for hydrogen relative to methane in the temperature range studied. The gas sensing mechanism has been suggested on the basis of the interaction of palladium with hydrogen, the change in the interface barrier, and the adsorption-desorption processes related to the change in the hydrogen partial pressure and temperature. The AFM study indicates the reorientation of the graphene surface after the sensing operation, most probably due to hydrogen passivation.

  18. Low Emission Hydrogen Combustors for Gas Turbines Using Lean Direct Injection

    NASA Technical Reports Server (NTRS)

    Marek, C. John; Smith, Timothy D.; Kundu, Krishna

    2005-01-01

    One of the key technology challenges for the use of hydrogen in gas turbine engines is the performance of the combustion system, in particular the fuel injectors. To investigate the combustion performance of gaseous hydrogen fuel injectors flame tube combustor experiments were performed. Tests were conducted to measure the nitrogen oxide (NOx) emissions and combustion performance at inlet conditions of 600 to 1000 deg F, 60 to 200 pounds per square inch absolute (psia), and equivalence ratios up to 0.48. All the injectors were based on Lean Direct Injection (LDI) technology with multiple injection points and quick mixing. One challenge to hydrogen based premixing combustion systems is flashback since hydrogen has a reaction rate over seven times that of Jet-A. To reduce the risk, design mixing times were kept short and velocities high to minimize flashback. Five fuel injector designs were tested in 2.5 and 3.5-in. diameter flame tubes with non-vitiated heated air and gaseous hydrogen. Data is presented on measurements of NOx emissions and combustion efficiency for the hydrogen injectors at 1.0, 3.125, and 5.375 in. from the injector face. Results show that for some configurations, NOx emissions are comparable to that of state of the art Jet-A LDI combustor concepts.

  19. Low-Emission Hydrogen Combustors for Gas Turbines Using Lean Direct Injection

    NASA Technical Reports Server (NTRS)

    Marek, C. John; Smith, Timothy D.; Kundu, Krishna

    2007-01-01

    One of the key technology challenges for the use of hydrogen in gas turbine engines is the performance of the combustion system, in particular the fuel injectors. To investigate the combustion performance of gaseous hydrogen fuel injectors flame tube combustor experiments were performed. Tests were conducted to measure the nitrogen oxide (NO(x)) emissions and combustion performance at inlet conditions of 588 to 811 K, 0.4 to 1.4 MPa, and equivalence ratios up to 0.48. All the injectors were based on Lean Direct Injection (LDI) technology with multiple injection points and quick mixing. One challenge to hydrogen-based premixing combustion systems is flashback since hydrogen has a reaction rate over 7 times that of Jet-A. To reduce the risk, design mixing times were kept short and velocities high to minimize flashback. Five fuel injector designs were tested in 6.35- and 8.9-cm-diameter flame tubes with non-vitiated heated air and gaseous hydrogen. Data is presented on measurements of NO(x) emissions and combustion efficiency for the hydrogen injectors at 2.540, 7.937, and 13.652 cm from the injector face. Results show that for some configurations, NO(x) emissions are comparable to that of state of the art Jet-A LDI combustor concepts.

  20. Production of hydrogen from coke-oven gas by the short-cycle adsorption method

    SciTech Connect

    Podorozhanskii, M.M.; Plichko, V.S.; Shustikov, V.I.; Yavorskaya, Z.G.

    1981-01-01

    In recent years the short-cycle adsorption method has been extensively used to separate hydrogen from hydrogen-containing gases in the petrochemical and chemical industries. With regard to coke-oven gas, which contains about 60% hydrogen, this problem has been given less attention in the literature. As the adsorbent, molecular sieves obtained from carbon have been used. Investigation of the process on a pilot apparatus demonstrated the possibility of using this method to produce hydrogen at a concentration of 95 to 99%. We have obtained similar data using an IGI (Institute of Fossil Fuels) microbead adsorbent with micropore volume of about 0.35 cm/sup 3//g. As a result of the experiments, it was concluded that: (1) the short-cycle adsorption method may be used to produce technical hydrogen suitable for use in hydrorefining processes; (2) an equation was derived describing the degree of purity of the hydrogen as a function of the productivity of a unit of adsorbent volume, the quantity of blowout gases and the duration of the cycle.

  1. 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

    2016-01-01

    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.

  2. Hydrogen gas sensor based on metal oxide nanoparticles decorated graphene transistor.

    PubMed

    Zhang, Zhangyuan; Zou, Xuming; Xu, Lei; Liao, Lei; Liu, Wei; Ho, Johnny; Xiao, Xiangheng; Jiang, Changzhong; Li, Jinchai

    2015-06-14

    In this work, in order to enhance the performance of graphene gas sensors, graphene and metal oxide nanoparticles (NPs) are combined to be utilized for high selectivity and fast response gas detection. Whether at the relatively optimal temperature or even room temperature, our gas sensors based on graphene transistors, decorated with SnO2 NPs, exhibit fast response and short recovery times (∼1 seconds) at 50 °C when the hydrogen concentration is 100 ppm. Specifically, X-ray photoelectron spectroscopy and conductive atomic force microscopy are employed to explore the interface properties between graphene and SnO2 NPs. Through the complimentary characterization, a mechanism based on charge transfer and band alignment is elucidated to explain the physical originality of these graphene gas sensors: high carrier mobility of graphene and small energy barrier between graphene and SnO2 NPs have ensured a fast response and a high sensitivity and selectivity of the devices. Generally, these gas sensors will facilitate the rapid development of next-generation hydrogen gas detection. PMID:25978618

  3. Hydrogen gas sensor based on metal oxide nanoparticles decorated graphene transistor.

    PubMed

    Zhang, Zhangyuan; Zou, Xuming; Xu, Lei; Liao, Lei; Liu, Wei; Ho, Johnny; Xiao, Xiangheng; Jiang, Changzhong; Li, Jinchai

    2015-06-14

    In this work, in order to enhance the performance of graphene gas sensors, graphene and metal oxide nanoparticles (NPs) are combined to be utilized for high selectivity and fast response gas detection. Whether at the relatively optimal temperature or even room temperature, our gas sensors based on graphene transistors, decorated with SnO2 NPs, exhibit fast response and short recovery times (∼1 seconds) at 50 °C when the hydrogen concentration is 100 ppm. Specifically, X-ray photoelectron spectroscopy and conductive atomic force microscopy are employed to explore the interface properties between graphene and SnO2 NPs. Through the complimentary characterization, a mechanism based on charge transfer and band alignment is elucidated to explain the physical originality of these graphene gas sensors: high carrier mobility of graphene and small energy barrier between graphene and SnO2 NPs have ensured a fast response and a high sensitivity and selectivity of the devices. Generally, these gas sensors will facilitate the rapid development of next-generation hydrogen gas detection.

  4. Nuclear breeder reactor fuel element with axial tandem stacking and getter

    DOEpatents

    Gibby, Ronald L.; Lawrence, Leo A.; Woodley, Robert E.; Wilson, Charles N.; Weber, Edward T.; Johnson, Carl E.

    1981-01-01

    A breeder reactor fuel element having a tandem arrangement of fissile and fertile fuel with a getter for fission product cesium disposed between the fissile and fertile sections. The getter is effective at reactor operating temperatures to isolate the cesium generated by the fissile material from reacting with the fertile fuel section.

  5. Determining air quality and greenhouse gas impacts of hydrogen infrastructure and fuel cell vehicles.

    PubMed

    Stephens-Romero, Shane; Carreras-Sospedra, Marc; Brouwer, Jacob; Dabdub, Donald; Samuelsen, Scott

    2009-12-01

    Adoption of hydrogen infrastructure and hydrogen fuel cell vehicles (HFCVs) to replace gasoline internal combustion engine (ICE) vehicles has been proposed as a strategy to reduce criteria pollutant and greenhouse gas (GHG) emissions from the transportation sector and transition to fuel independence. However, it is uncertain (1) to what degree the reduction in criteria pollutants will impact urban air quality, and (2) how the reductions in pollutant emissions and concomitant urban air quality impacts compare to ultralow emission gasoline-powered vehicles projected for a future year (e.g., 2060). To address these questions, the present study introduces a "spatially and temporally resolved energy and environment tool" (STREET) to characterize the pollutant and GHG emissions associated with a comprehensive hydrogen supply infrastructure and HFCVs at a high level of geographic and temporal resolution. To demonstrate the utility of STREET, two spatially and temporally resolved scenarios for hydrogen infrastructure are evaluated in a prototypical urban airshed (the South Coast Air Basin of California) using geographic information systems (GIS) data. The well-to-wheels (WTW) GHG emissions are quantified and the air quality is established using a detailed atmospheric chemistry and transport model followed by a comparison to a future gasoline scenario comprised of advanced ICE vehicles. One hydrogen scenario includes more renewable primary energy sources for hydrogen generation and the other includes more fossil fuel sources. The two scenarios encompass a variety of hydrogen generation, distribution, and fueling strategies. GHG emissions reductions range from 61 to 68% for both hydrogen scenarios in parallel with substantial improvements in urban air quality (e.g., reductions of 10 ppb in peak 8-h-averaged ozone and 6 mug/m(3) in 24-h-averaged particulate matter concentrations, particularly in regions of the airshed where concentrations are highest for the gasoline scenario

  6. Determining air quality and greenhouse gas impacts of hydrogen infrastructure and fuel cell vehicles.

    PubMed

    Stephens-Romero, Shane; Carreras-Sospedra, Marc; Brouwer, Jacob; Dabdub, Donald; Samuelsen, Scott

    2009-12-01

    Adoption of hydrogen infrastructure and hydrogen fuel cell vehicles (HFCVs) to replace gasoline internal combustion engine (ICE) vehicles has been proposed as a strategy to reduce criteria pollutant and greenhouse gas (GHG) emissions from the transportation sector and transition to fuel independence. However, it is uncertain (1) to what degree the reduction in criteria pollutants will impact urban air quality, and (2) how the reductions in pollutant emissions and concomitant urban air quality impacts compare to ultralow emission gasoline-powered vehicles projected for a future year (e.g., 2060). To address these questions, the present study introduces a "spatially and temporally resolved energy and environment tool" (STREET) to characterize the pollutant and GHG emissions associated with a comprehensive hydrogen supply infrastructure and HFCVs at a high level of geographic and temporal resolution. To demonstrate the utility of STREET, two spatially and temporally resolved scenarios for hydrogen infrastructure are evaluated in a prototypical urban airshed (the South Coast Air Basin of California) using geographic information systems (GIS) data. The well-to-wheels (WTW) GHG emissions are quantified and the air quality is established using a detailed atmospheric chemistry and transport model followed by a comparison to a future gasoline scenario comprised of advanced ICE vehicles. One hydrogen scenario includes more renewable primary energy sources for hydrogen generation and the other includes more fossil fuel sources. The two scenarios encompass a variety of hydrogen generation, distribution, and fueling strategies. GHG emissions reductions range from 61 to 68% for both hydrogen scenarios in parallel with substantial improvements in urban air quality (e.g., reductions of 10 ppb in peak 8-h-averaged ozone and 6 mug/m(3) in 24-h-averaged particulate matter concentrations, particularly in regions of the airshed where concentrations are highest for the gasoline scenario).

  7. Hydrogen storage materials discovery via high throughput ball milling and gas sorption.

    PubMed

    Li, Bin; Kaye, Steven S; Riley, Conor; Greenberg, Doron; Galang, Daniel; Bailey, Mark S

    2012-06-11

    The lack of a high capacity hydrogen storage material is a major barrier to the implementation of the hydrogen economy. To accelerate discovery of such materials, we have developed a high-throughput workflow for screening of hydrogen storage materials in which candidate materials are synthesized and characterized via highly parallel ball mills and volumetric gas sorption instruments, respectively. The workflow was used to identify mixed imides with significantly enhanced absorption rates relative to Li2Mg(NH)2. The most promising material, 2LiNH2:MgH2 + 5 atom % LiBH4 + 0.5 atom % La, exhibits the best balance of absorption rate, capacity, and cycle-life, absorbing >4 wt % H2 in 1 h at 120 °C after 11 absorption-desorption cycles.

  8. Cathode sheath and hydrogen Balmer lines modelling in a micro-hollow gas discharge

    NASA Astrophysics Data System (ADS)

    Spasojević, Dj

    2012-11-01

    We present a model of the cathode sheath (CS) processes responsible for the broadening of the hydrogen Balmer beta line recorded from a micro-hollow gas discharge (MHGD) and used for simultaneous diagnostics of plasma and CS parameters. The MHGD was generated in a microhole (diameter 100 μm at narrow side and 130 μm at wider side) of a gold-alumina-gold sandwich in the pressure ranges: (100-900) mbar in argon with traces of hydrogen, and (100-400) mbar in pure hydrogen. The electron number density is determined from the plasma broadened line width of the central part of Balmer beta profile, while the average value of electric field strength in the CS and the CS thickness are determined from the extended line wings induced by the dc Stark effect.

  9. Detection of deuterium and hydrogen using laser-induced helium gas plasma at atmospheric pressure

    SciTech Connect

    Kurniawan, Koo Hendrik; Lie, Tjung Jie; Suliyanti, Maria Margaretha; Hedwig, Rinda; Abdulmadjid, Syahrun Nur; Pardede, Marincan; Idris, Nasrullah; Kobayashi, Takao; Kusumoto, Yoshihumi; Kagawa, Kiichiro; Tjia, May On

    2005-11-01

    An experimental study on gas analysis by means of laser-induced breakdown spectroscopy was conducted using a Nd-yttrium aluminum garnet laser (1,064 nm, 120 mJ, 8 ns) and helium host gas at atmospheric pressure on a sample of mixed water (H{sub 2}O) and heavy water (D{sub 2}O) in vapor form. It was shown that completely resolved hydrogen (H{sub {alpha}}) and deuterium (D{sub {alpha}}) emission lines that are separated by only 0.179 nm could be obtained at a properly delayed detection time when the charged particles responsible for the strong Stark broadening effect in the plasma have mostly disappeared. It is argued that the helium metastable excited state plays an important role in the hydrogen excitation process.

  10. Development of a hydrogen gas sensor using a double SAW resonator system at room temperature.

    PubMed

    Yunusa, Zainab; Hamidon, Mohd Nizar; Ismail, Alyani; Mohd Isa, Maryam; Yaacob, Mohd Hanif; Rahmanian, Saeed; Ibrahim, Siti Azlida; Shabaneh, Arafat A A

    2015-01-01

    A double SAW resonator system was developed as a novel method for gas sensing applications. The proposed system was investigated for hydrogen sensing. Commercial Surface Acoustic Wave (SAW) resonators with resonance frequencies of 433.92 MHz and 433.42 MHz were employed in the double SAW resonator system configuration. The advantages of using this configuration include its ability for remote measurements, and insensitivity to vibrations and other external disturbances. The sensitive layer is composed of functionalized multiwalled carbon nanotubes and polyaniline nanofibers which were deposited on pre-patterned platinum metal electrodes fabricated on a piezoelectric substrate. This was mounted into the DSAWR circuit and connected in parallel. The sensor response was measured as the difference between the resonance frequencies of the SAW resonators, which is a measure of the gas concentration. The sensor showed good response towards hydrogen with a minimum detection limit of 1%.

  11. Development of a Hydrogen Gas Sensor Using a Double Saw Resonator System at Room Temperature

    PubMed Central

    Yunusa, Zainab; Hamidon, Mohd Nizar; Ismail, Alyani; Isa, Maryam Mohd; Yaacob, Mohd Hanif; Rahmanian, Saeed; Ibrahim, Siti Azlida; Shabaneh, Arafat A.A

    2015-01-01

    A double SAW resonator system was developed as a novel method for gas sensing applications. The proposed system was investigated for hydrogen sensing. Commercial Surface Acoustic Wave (SAW) resonators with resonance frequencies of 433.92 MHz and 433.42 MHz were employed in the double SAW resonator system configuration. The advantages of using this configuration include its ability for remote measurements, and insensitivity to vibrations and other external disturbances. The sensitive layer is composed of functionalized multiwalled carbon nanotubes and polyaniline nanofibers which were deposited on pre-patterned platinum metal electrodes fabricated on a piezoelectric substrate. This was mounted into the DSAWR circuit and connected in parallel. The sensor response was measured as the difference between the resonance frequencies of the SAW resonators, which is a measure of the gas concentration. The sensor showed good response towards hydrogen with a minimum detection limit of 1%. PMID:25730480

  12. Probabilistic simulation of hydrogen gas porosity formation in A356 base hypoeutectic alloy castings

    NASA Astrophysics Data System (ADS)

    Asada, Jo

    Microporosity in cast aluminum alloy can be classified as gas porosity and/or shrinkage porosity. In prior research, two dimensional simulation programs employing a probabilistic modeling approach and cellular automaton method were developed to predict microporosity in cast aluminum alloys. In this research the 2D models were statistically compared with experimental data. Additionally, we investigated size and morphology distribution of grains and porosity in A356 alloy castings under variable hydrogen content and alloy treatment condition, i.e. eutectic phase modification and grain refinement. In order to improve the accuracy of the prediction method, new simulation models including a two and half dimensional analysis and a two phase evolution model were developed in the present body of work. The new models were statistically compared with experimental results changing silicon and hydrogen content and alloy treatment conditions. The new simulation technique exhibits improved agreement with experimental data tracking the morphology of gas porosities and the grain size distribution.

  13. Identification of gas-phase dimethyl sulfate and monomethyl hydrogen sulfate in the Los Angeles atmosphere

    SciTech Connect

    Eatough, D.J.; White, V.F.; Hansen, L.D.; Eatough, N.L.; Cheney, J.L.

    1986-09-01

    Gas-phase dimethyl sulfate and monomethyl hydrogen sulfate have been identified in the atmosphere in Los Angeles. Gas-phase concentrations of these two alkyl sulfates were determined by using analytical methods based on the collection of the compounds before collection of particles using diffusion denuders and after collection of particles using resin beds or sorption filters, and specific analysis of the collected alkyl sulfates by ion chromatography. The data show the dimethyl sulfate is present in both particles and the gas phase. The concentration of total gas-phase methyl sulfates was found to vary from 34 to 178 nmol/m/sup 3/ during the smog episode studied. These species constituted a significant fraction of the total sulfur budget in the Los Angeles basin during the sampling period.

  14. Gas-Phase Reaction Pathways and Rate Coefficients for the Dichlorosilane-Hydrogen and Trichlorosilane-Hydrogen Systems

    NASA Technical Reports Server (NTRS)

    Dateo, Christopher E.; Walch, Stephen P.

    2002-01-01

    As part of NASA Ames Research Center's Integrated Process Team on Device/Process Modeling and Nanotechnology our goal is to create/contribute to a gas-phase chemical database for use in modeling microelectronics devices. In particular, we use ab initio methods to determine chemical reaction pathways and to evaluate reaction rate coefficients. Our initial studies concern reactions involved in the dichlorosilane-hydrogen (SiCl2H2--H2) and trichlorosilane-hydrogen (SiCl2H-H2) systems. Reactant, saddle point (transition state), and product geometries and their vibrational harmonic frequencies are determined using the complete-active-space self-consistent-field (CASSCF) electronic structure method with the correlation consistent polarized valence double-zeta basis set (cc-pVDZ). Reaction pathways are constructed by following the imaginary frequency mode of the saddle point to both the reactant and product. Accurate energetics are determined using the singles and doubles coupled-cluster method that includes a perturbational estimate of the effects of connected triple excitations (CCSD(T)) extrapolated to the complete basis set limit. Using the data from the electronic structure calculations, reaction rate coefficients are obtained using conventional and variational transition state and RRKM theories.

  15. Colouration process of colloidal tungsten oxide nanoparticles in the presence of hydrogen gas

    NASA Astrophysics Data System (ADS)

    Tahmasebi Garavand, N.; Ranjbar, M.; Mahdavi, S. M.; Iraji zad, A.

    2012-10-01

    In this study, tungsten oxide nanoparticles were fabricated by pulsed laser ablation (PLA) of tungsten target using the first harmonic of a Nd:YAG laser (1064 nm) in deionized water. After ablation, a 0.2 g/lit PdCl2 solution was added to activate the solution against the hydrogen gas. Dynamic light scattering and X-ray photoelectron spectroscopy were used to measure the average size and the surface chemical composition of the synthesized nanoparticles, respectively. The aim is to investigate the influence of hydrogen exposure time on colouration process of colloidal nanoparticles. According to optical measurements, hydrogen bubbling into the produced colloidal Pd-WO3 led to formation of several absorption peaks at ∼1.26, ∼1.6 and ∼1.97 eV. We observed the appearance and growth of a peak at 1.6 eV at the initial stages of hydrogen exposure. However, two other peaks became dominant at long exposure times. The coloration process is reversible in the presence of oxygen gas.

  16. Hydrogen turbines for space power systems: A simplified axial flow gas turbine model

    SciTech Connect

    Hudson, S.L.

    1988-01-01

    This paper descirbes a relatively simple axial flow gas expansion turbine mass model, which we developed for use in our space power system studies. The model uses basic engineering principles and realistic physical properties, including gas conditions, power level, and material stresses, to provide reasonable and consistent estimates of turbine mass and size. Turbine design modifications caused by boundary layer interactions, stress concentrations, stage leakage, or bending and thermal stresses are not accounted for. The program runs on an IBM PC, uses little computer time and has been incorporated into our system-level space power platform analysis computer codes. Parametric design studies of hydrogen turbines using this model are presented for both nickel superalloy and carbon/carbon composite turbines. The effects of speed, pressure ratio, and power level on hydrogen turbine mass are shown and compared to a baseline case 100-MWe, 10,000-rpm hydrogen turbine. Comparison with more detailed hydrogen turbine designs indicates that our simplified model provides mass estimates that are within 25% of the ones provided by more complex calculations. 8 figs.

  17. Analysis of the benefits of carbon credits to hydrogen addition to midsize gas turbine feedstocks.

    SciTech Connect

    Miller, J.; Towns, B.; Keller, Jay O.; Schefer, Robert W.; Skolnik, Edward G.

    2006-02-01

    The addition of hydrogen to the natural gas feedstocks of midsize (30-150 MW) gas turbines was analyzed as a method of reducing nitrogen oxides (NO{sub x}) and CO{sub 2} emissions. In particular, the costs of hydrogen addition were evaluated against the combined costs for other current NO{sub x} and CO{sub 2} emissions control technologies for both existing and new systems to determine its benefits and market feasibility. Markets for NO{sub x} emissions credits currently exist in California and the Northeast States and are expected to grow. Although regulations are not currently in place in the United States, several other countries have implemented carbon tax and carbon credit programs. The analysis thus assumes that the United States adopts future legislation similar to these programs. Therefore, potential sale of emissions credits for volunteer retrofits was also included in the study. It was found that hydrogen addition is a competitive alternative to traditional emissions abatement techniques under certain conditions. The existence of carbon credits shifts the system economics in favor of hydrogen addition.

  18. Process for producing methane from gas streams containing carbon monoxide and hydrogen

    DOEpatents

    Frost, Albert C.

    1980-01-01

    Carbon monoxide-containing gas streams are passed over a catalyst capable of catalyzing the disproportionation of carbon monoxide so as to deposit a surface layer of active surface carbon on the catalyst essentially without formation of inactive coke thereon. The surface layer is contacted with steam and is thus converted to methane and CO.sub.2, from which a relatively pure methane product may be obtained. While carbon monoxide-containing gas streams having hydrogen or water present therein can be used only the carbon monoxide available after reaction with said hydrogen or water is decomposed to form said active surface carbon. Although hydrogen or water will be converted, partially or completely, to methane that can be utilized in a combustion zone to generate heat for steam production or other energy recovery purposes, said hydrogen is selectively removed from a CO--H.sub.2 -containing feed stream by partial oxidation thereof prior to disproportionation of the CO content of said stream.

  19. Time-dependent gas phase kinetics in a hydrogen diluted silane plasma

    SciTech Connect

    Nunomura, S.; Kondo, M.; Yoshida, I.

    2009-02-16

    The gas phase kinetics in a high-pressure hydrogen diluted silane plasma has been studied at time scales of 10{sup -2}-6x10{sup 2} s. The time-resolved gas phase composition shows the following kinetics at different time scales: silane decomposition and polysilane generation in < or approx. 2x10{sup -1} s, nanoparticle formation and plasma density reduction in 10{sup -1}-10{sup 0} s, polysilane accumulation in 10{sup 0}-10{sup 2} s, and silane depletion and electrode heating in > or approx. 10{sup 1} s. Disilane radicals are implied to be the dominant film precursors in addition to silyl radicals.

  20. Life-cycle assessment of diesel, natural gas and hydrogen fuel cell bus transportation systems

    NASA Astrophysics Data System (ADS)

    Ally, Jamie; Pryor, Trevor

    The Sustainable Transport Energy Programme (STEP) is an initiative of the Government of Western Australia, to explore hydrogen fuel cell technology as an alternative to the existing diesel and natural gas public transit infrastructure in Perth. This project includes three buses manufactured by DaimlerChrysler with Ballard fuel cell power sources operating in regular service alongside the existing natural gas and diesel bus fleets. The life-cycle assessment (LCA) of the fuel cell bus trial in Perth determines the overall environmental footprint and energy demand by studying all phases of the complete transportation system, including the hydrogen infrastructure, bus manufacturing, operation, and end-of-life disposal. The LCAs of the existing diesel and natural gas transportation systems are developed in parallel. The findings show that the trial is competitive with the diesel and natural gas bus systems in terms of global warming potential and eutrophication. Emissions that contribute to acidification and photochemical ozone are greater for the fuel cell buses. Scenario analysis quantifies the improvements that can be expected in future generations of fuel cell vehicles and shows that a reduction of greater than 50% is achievable in the greenhouse gas, photochemical ozone creation and primary energy demand impact categories.

  1. Stable Isotope Measurements of Carbon Dioxide, Methane, and Hydrogen Sulfide Gas Using Frequency Modulation Spectroscopy

    NASA Astrophysics Data System (ADS)

    Nowak-Lovato, K.

    2014-12-01

    Seepage from enhanced oil recovery, carbon storage, and natural gas sites can emit trace gases such as carbon dioxide, methane, and hydrogen sulfide. Trace gas emission at these locations demonstrate unique light stable isotope signatures that provide information to enable source identification of the material. Light stable isotope detection through surface monitoring, offers the ability to distinguish between trace gases emitted from sources such as, biological (fertilizers and wastes), mineral (coal or seams), or liquid organic systems (oil and gas reservoirs). To make light stable isotope measurements, we employ the ultra-sensitive technique, frequency modulation spectroscopy (FMS). FMS is an absorption technique with sensitivity enhancements approximately 100-1000x more than standard absorption spectroscopy with the advantage of providing stable isotope signature information. We have developed an integrated in situ (point source) system that measures carbon dioxide, methane and hydrogen sulfide with isotopic resolution and enhanced sensitivity. The in situ instrument involves the continuous collection of air and records the stable isotope ratio for the gas being detected. We have included in-line flask collection points to obtain gas samples for validation of isotopic concentrations using our in-house isotope ratio mass spectroscopy (IRMS). We present calibration curves for each species addressed above to demonstrate the sensitivity and accuracy of the system. We also show field deployment data demonstrating the capabilities of the system in making live dynamic measurements from an active source.

  2. Control of hydrocarbon content of a reforming gas by using a hydrogenation catalyst.

    PubMed

    Inoue, Kenichiro; Kawamoto, Katsuya

    2010-01-01

    To control of hydrocarbon content in waste pyrolysis-gasification and reforming processes, the use of a hydrogenation catalyst was examined in a test system with a model gas. To reduce the concentration of benzene in the reforming gas, benzene was hydrogenated with a nickel catalyst. The catalyst is usually used to convert gas-phase unsaturated hydrocarbons to saturated hydrocarbons, and the benzene was converted to cyclohexane at a temperature range of about 130 to 180 degrees C in the presence of steam. However, the conversion to methane occurred at about 250 to 300 degrees C. Methane seems to be a useful conversion compound because it does not cohere as a light tar. Sometimes the reforming gas needs to be cooled for use as generator fuel. In this case, it is possible to avoid the tar cohesion if the benzene in the gas is converted to methane at about 300 degrees C after the reforming. Reduction of the efficiency of conversion to methane was not observed over a 60h reaction period. The lower hydrocarbons (ethylene, ethane, and propylene) were also converted to methane at about 300 degrees C. Conversion of benzene was also possible when other hydrocarbons were present at high concentrations. PMID:20022077

  3. Process for generation of hydrogen gas from various feedstocks using thermophilic bacteria

    DOEpatents

    Ooteghem, Suellen Van

    2005-09-13

    A method for producing hydrogen gas is provided comprising selecting a bacteria from the Order Thermotogales, subjecting the bacteria to a feedstock and to a suitable growth environment having an oxygen concentration below the oxygen concentration of water in equilibrium with air; and maintaining the environment at a predetermined pH and at a temperature of at least approximately 45.degree. C. for a time sufficient to allow the bacteria to metabolize the feedstock.

  4. Aqueous process for recovering sulfur from hydrogen sulfide-bearing gas

    SciTech Connect

    Basu, Arunabha

    2015-05-05

    A process for recovering sulfur from a hydrogen sulfide-bearing gas utilizes an aqueous reaction medium, a temperature of about 110-150.degree. C., and a high enough pressure to maintain the aqueous reaction medium in a liquid state. The process reduces material and equipment costs and addresses the environmental disadvantages associated with known processes that rely on high boiling point organic solvents.

  5. Process for Generation of Hydrogen Gas from Various Feedstocks Using Thermophilic Bacteria

    SciTech Connect

    Ooteghem Van, Suellen

    2005-09-13

    A method for producing hydrogen gas is provided comprising selecting a bacteria from the Order Thermotogales, subjecting the bacteria to a feedstock and to a suitable growth environment having an oxygen concentration below the oxygen concentration of water in equilibrium with air; and maintaining the environment at a predetermined pH and at a temperature of at least approximately 45 degrees C. for a time sufficient to allow the bacteria to metabolize the feedstock.

  6. Intermediate energy proton stopping power for hydrogen molecules and monoatomic helium gas

    NASA Technical Reports Server (NTRS)

    Xu, Y. J.; Khandelwal, G. S.; Wilson, J. W.

    1984-01-01

    Stopping power in the intermediate energy region (100 keV to 1 MeV) was investigated, based on the work of Lindhard and Winther, and on the local plasma model. The theory is applied to calculate stopping power of hydrogen molecules and helium gas for protons of energy ranging from 100 keV to 2.5 MeV. Agreement with the experimental data is found to be within 10 percent.

  7. Nuclear reactor fuel element with vanadium getter on cladding

    DOEpatents

    Johnson, Carl E.; Carroll, Kenneth G.

    1977-01-01

    A nuclear reactor fuel element is described which has an outer cladding, a central core of fissionable or mixed fissionable and fertile fuel material and a layer of vanadium as an oxygen getter on the inner surface of the cladding. The vanadium reacts with oxygen released by the fissionable material during irradiation of the core to prevent the oxygen from reacting with and corroding the cladding. Also described is a method for coating the inner surface of small diameter tubes of cladding with a layer of vanadium.

  8. Hydrogen turbines for space power systems: A simplified axial flow gas turbine model

    NASA Technical Reports Server (NTRS)

    Hudson, Steven L.

    1988-01-01

    Hydrogen cooled, turbine powered space weapon systems require a relatively simple, but reasonably accurate hydrogen gas expansion turbine model. Such a simplified turbine model would require little computational time and allow incorporation into system level computer programs while providing reasonably accurate volume/mass estimates. This model would then allow optimization studies to be performed on multiparameter space power systems and provide improved turbine mass and size estimates for the various operating conditions (when compared to empirical and power law approaches). An axial flow gas expansion turbine model was developed for these reasons and is in use as a comparative bench mark in space power system studies at Sandia. The turbine model is based on fluid dynamic, thermodynamic, and material strength considerations, but is considered simplified because it does not account for design details such as boundary layer effects, shock waves, turbulence, stress concentrations, and seal leakage. Although the basic principles presented here apply to any gas or vapor axial flow turbine, hydrogen turbines are discussed because of their immense importance on space burst power platforms.

  9. Improvement of saturation magnetization of Fe nanoparticles by post-annealing in a hydrogen gas atmosphere

    SciTech Connect

    Kin, Masane Tanaka, Masaaki; Hayashi, Yasushi; Hasaegawa, Jun; Kura, Hiroaki; Ogawa, Tomoyuki

    2015-05-07

    Fe nanoparticles (NPs) were synthesized by the thermal decomposition of Fe(CO){sub 5} and then post-annealing in a hydrogen gas atmosphere to produce highly monodisperse Fe NPs with high saturation magnetization (M{sub s}). The as-synthesized pre-anneal Fe NPs had an expanded α-Fe structure and M{sub s} was only 39% of that for bulk Fe because of the low crystallinity and the inclusion of a surfactant. Post-annealing of the Fe NPs in a hydrogen gas atmosphere at 200 °C improved the crystallinity of the Fe NPs from an amorphous-like structure to a body centered cubic (bcc) structure without any lattice expansion. This result indicates that hydrogen gas plays a significant role in improvement of the crystallinity of Fe NPs. Accompanying the improvement in crystallinity, M{sub s} for the Fe NPs increased from 86 to 190 emu/g{sub net} at 300 K, the values of which include the weight of surfactant. This enhanced M{sub s} is almost the same as that of bulk Fe (218 emu/{sub Fe}). It was concluded that the crystallinity has a significant influence on the M{sub s} of the Fe NPs because long-range ordering of the lattice can maintain strong direct exchange interactions between Fe atoms.

  10. SiC-BASED HYDROGEN SELECTIVE MEMBRANES FOR WATER-GAS-SHIFT REACTION

    SciTech Connect

    Unknown

    2000-12-01

    A hydrogen selective membrane as a membrane reactor (MR) can significantly improve the power generation efficiency with a reduced capital and operating cost for the waster-gas-shift reaction. Existing hydrogen selective ceramic membranes are not suitable for the proposed MR due to their poor hydrothermal stability. In this project we have focused on the development of innovative silicon carbide (SiC) based hydrogen selective membranes, which can potentially overcome this technical barrier. During Year I, we have successfully fabricated SiC macro porous membranes via extrusion of commercially available SiC powder, which were then deposited with thin, micro-porous (6 to 40{angstrom} in pore size) films via sol-gel technique as intermediate layers. Finally, an SiC hydrogen selective thin film was deposited on this substrate via our CVD/I technique. The composite membrane thus prepared demonstrated excellent hydrogen selectivity at high temperature ({approx}600 C). More importantly, this membrane also exhibited a much improved hydrothermal stability at 600 C with 50% steam (atmospheric pressure) for nearly 100 hours. In parallel, we have explored an alternative approach to develop a H{sub 2} selective SiC membrane via pyrolysis of selected pre-ceramic polymers. Building upon the positive progress made in the Year I preliminary study, we will conduct an optimization study in Year II to develop an optimized H{sub 2} selective SiC membrane with sufficient hydrothermal stability suitable for the WGS environment.

  11. Hydrogen sensor

    DOEpatents

    Duan, Yixiang; Jia, Quanxi; Cao, Wenqing

    2010-11-23

    A hydrogen sensor for detecting/quantitating hydrogen and hydrogen isotopes includes a sampling line and a microplasma generator that excites hydrogen from a gas sample and produces light emission from excited hydrogen. A power supply provides power to the microplasma generator, and a spectrometer generates an emission spectrum from the light emission. A programmable computer is adapted for determining whether or not the gas sample includes hydrogen, and for quantitating the amount of hydrogen and/or hydrogen isotopes are present in the gas sample.

  12. ANALYSIS OF A HIGH TEMPERATURE GAS-COOLED REACTOR POWERED HIGH TEMPERATURE ELECTROLYSIS HYDROGEN PLANT

    SciTech Connect

    M. G. McKellar; E. A. Harvego; A. M. Gandrik

    2010-11-01

    An updated reference design for a commercial-scale high-temperature electrolysis (HTE) plant for hydrogen production has been developed. The HTE plant is powered by a high-temperature gas-cooled reactor (HTGR) whose configuration and operating conditions are based on the latest design parameters planned for the Next Generation Nuclear Plant (NGNP). The current HTGR reference design specifies a reactor power of 600 MWt, with a primary system pressure of 7.0 MPa, and reactor inlet and outlet fluid temperatures of 322°C and 750°C, respectively. The reactor heat is used to produce heat and electric power to the HTE plant. A Rankine steam cycle with a power conversion efficiency of 44.4% was used to provide the electric power. The electrolysis unit used to produce hydrogen includes 1.1 million cells with a per-cell active area of 225 cm2. The reference hydrogen production plant operates at a system pressure of 5.0 MPa, and utilizes a steam-sweep system to remove the excess oxygen that is evolved on the anode (oxygen) side of the electrolyzer. The overall system thermal-to-hydrogen production efficiency (based on the higher heating value of the produced hydrogen) is 42.8% at a hydrogen production rate of 1.85 kg/s (66 million SCFD) and an oxygen production rate of 14.6 kg/s (33 million SCFD). An economic analysis of this plant was performed with realistic financial and cost estimating The results of the economic analysis demonstrated that the HTE hydrogen production plant driven by a high-temperature helium-cooled nuclear power plant can deliver hydrogen at a competitive cost. A cost of $3.03/kg of hydrogen was calculated assuming an internal rate of return of 10% and a debt to equity ratio of 80%/20% for a reactor cost of $2000/kWt and $2.41/kg of hydrogen for a reactor cost of $1400/kWt.

  13. DECONTAMINATION ASSESSMENT OF BACILLUS ANTHRACIS, BACILLUS SUBTILIS, AND GEOBACILLUS STEAROTHERMOPHILUS SPORES ON INDOOR SURFACTS USING A HYDROGEN PERIOXIDE GAS GENERATOR

    EPA Science Inventory

    Aims: To evaluate the decontamination of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surface materials using hydrogen peroxide gas. Methods and Results: B. anthracis, B. subtilis, and G. Stearothermophilus spores were dried on seven...

  14. SIC-BASED HYDROGEN SELECTIVE MEMBRANES FOR WATER-GAS-SHIFT REACTION

    SciTech Connect

    Paul K.T. Liu

    2003-12-01

    A hydrogen selective membrane as a membrane reactor (MR) can significantly improve the power generation efficiency with a reduced capital and operating cost for the waster-gas-shift reaction. Existing hydrogen selective ceramic membranes are not suitable for the proposed MR due to their poor hydrothermal stability. In this project we have focused on the development of innovative silicon carbide (SiC) based hydrogen selective membranes, which can potentially overcome this technical barrier. SiC macro-porous membranes have been successfully fabricated via extrusion of commercially available SiC powder. Also, an SiC hydrogen selective thin film was prepared via our CVD/I technique. This composite membrane demonstrated excellent hydrogen selectivity at high temperature ({approx}600 C). More importantly, this membrane also exhibited a much improved hydrothermal stability at 600 C with 50% steam (atmospheric pressure) for nearly 100 hours. In parallel, we have explored an alternative approach to develop a H{sub 2} selective SiC membrane via pyrolysis of selected pre-ceramic polymers and sol-gel techniques. Building upon the positive progress made in the membrane development study, we conducted an optimization study to develop an H{sub 2} selective SiC membrane with sufficient hydrothermal stability suitable for the WGS environment. In addition, mathematical simulation has been performed to compare the performance of the membrane reactor (MR) vs conventional packed bed reactor for WGS reaction. Our result demonstrates that >99.999% conversion can be accomplished via WGS-MR using the hydrogen selective membrane developed by us. Further, water/CO ratio can be reduced, and >97% hydrogen recovery and <200 ppm CO can be accomplished according to the mathematical simulation. Thus, we believe that the operating economics of WGS can be improved significantly based upon the proposed MR concept. In parallel, gas separations and hydrothermal and long-term-storage stability of the

  15. Overview of geologic storage of natural gas with an emphasis on assessing the feasibility of storing hydrogen.

    SciTech Connect

    Lord, Anna Snider

    2009-09-01

    In many regions across the nation geologic formations are currently being used to store natural gas underground. Storage options are dictated by the regional geology and the operational need. The U.S. Department of Energy (DOE) has an interest in understanding theses various geologic storage options, the advantages and disadvantages, in the hopes of developing an underground facility for the storage of hydrogen as a low cost storage option, as part of the hydrogen delivery infrastructure. Currently, depleted gas/oil reservoirs, aquifers, and salt caverns are the three main types of underground natural gas storage in use today. The other storage options available currently and in the near future, such as abandoned coal mines, lined hard rock caverns, and refrigerated mined caverns, will become more popular as the demand for natural gas storage grows, especially in regions were depleted reservoirs, aquifers, and salt deposits are not available. The storage of hydrogen within the same type of facilities, currently used for natural gas, may add new operational challenges to the existing cavern storage industry, such as the loss of hydrogen through chemical reactions and the occurrence of hydrogen embrittlement. Currently there are only three locations worldwide, two of which are in the United States, which store hydrogen. All three sites store hydrogen within salt caverns.

  16. Plasma-chemical treatment of hydrogen sulfide in natural gas processing. Final report, May 1991--December 1992

    SciTech Connect

    Harkness, J.B.L.; Doctor, R.D.

    1993-05-01

    A new process for the treatment of hydrogen sulfide waste that uses microwave plasma-chemical technology has been under development in Russia and the United States. Whereas the present waste-treatment technology, at best, only recovers sulfur, this novel process recovers both hydrogen and sulfur by dissociating hydrogen sulfide in a plasma by means of a microwave or radio-frequency reactor. A research project has been undertaken to determine the suitability of the plasma process in natural gas processing applications. The experiments tested acid-gas compositions with 30--65% carbon dioxide, 0--7% water, and 0--0.2% of a standard mixture of pipeline gas. The balance gas in all cases was hydrogen sulfide. The reactor pressure for the experiments was 50 torr, and the microwave power was 1.0 kW. Conversions of hydrogen sulfide ranged from 80 to 100%, while 35--50% of the carbon dioxide was converted to carbon monoxide. This conversion of carbon dioxide resulted in a loss of hydrogen production and an energy loss from a hydrogen sulfide waste-treatment perspective. Tests of a direct natural gas treatment concept showed that hydrocarbon losses were unacceptably high; consequently, the concept would not be economically viable.

  17. Development of a Low NOx Medium-Sized Industrial Gas Turbine Operating on Hydrogen-Rich Renewable and Opportunity Fuels

    SciTech Connect

    2009-11-01

    Solar Turbines Inc., in collaboration with Pennsylvania State University and the University of Southern California, will develop injector technologies for gas turbine use of high-hydrogen content renewable and opportunity fuels derived from coal, biomass, industrial process waste, or byproducts. This project will develop low-emission technology for alternate fuels with high-hydrogen content, thereby reducing natural gas requirements and lowering carbon intensity.

  18. 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.

  19. Mechanism of Hydrogen Formation in Solar Parabolic Trough Receivers

    SciTech Connect

    Moens, L.; Blake, D. M.

    2008-03-01

    Solar parabolic trough systems for electricity production are receiving renewed attention, and new solar plants are under construction to help meet the growing demands of the power market in the Western United States. The growing solar trough industry will rely on operating experience it has gained over the last two decades. Recently, researchers found that trough plants that use organic heat transfer fluids (HTF) such as Therminol VP-1 are experiencing significant heat losses in the receiver tubes. The cause has been traced back to the accumulation of excess hydrogen gas in the vacuum annulus that surrounds the steel receiver tube, thus compromising the thermal insulation of the receiver. The hydrogen gas is formed during the thermal decomposition of the organic HTF that circulates inside the receiver loop, and the installation of hydrogen getters inside the annulus has proven to be insufficient for controlling the hydrogen build-up over the lifetime of the receivers. This paper will provide an overview of the chemical literature dealing with the thermal decomposition of diphenyl oxide and biphenyl, the two constituents of Therminol VP-1.

  20. Sampling and determination of gas-phase hydrogen peroxide following removal of ozone by gas-phase reaction with nitric oxide

    SciTech Connect

    Tanner, R.L.; Markovits, G.Y.; Ferreri, E.M.; Kelly, T.J.

    1986-01-01

    A method for determination of hydrogen peroxide in the ambient atmosphere is described, using impinger or diffusion scrubber collection of hydrogen peroxide with aqueous-phase analysis by an enzyme-catalyzed fluorescence technique. Interference from ozone at ambient levels is removed by gas-phase titration with excess nitric oxide. The impinger and diffusion scrubber collection techniques are shown to give equivalent results for atmospheric gas-phase hydrogen peroxide with limits of detection of 0.1 ppbv for approximately 60-min and 10-min sampling times, respectively.

  1. Hydrogen Gas Retention and Release from WTP Vessels: Summary of Preliminary Studies

    SciTech Connect

    Gauglitz, Phillip A.; Bontha, Jagannadha R.; Daniel, Richard C.; Mahoney, Lenna A.; Rassat, Scot D.; Wells, Beric E.; Bao, Jie; Boeringa, Gregory K.; Buchmiller, William C.; Burns, Carolyn A.; Chun, Jaehun; Karri, Naveen K.; Li, Huidong; Tran, Diana N.

    2015-07-01

    The Hanford Waste Treatment and Immobilization Plant (WTP) is currently being designed and constructed to pretreat and vitrify a large portion of the waste in the 177 underground waste storage tanks at the Hanford Site. A number of technical issues related to the design of the pretreatment facility (PTF) of the WTP have been identified. These issues must be resolved prior to the U.S. Department of Energy (DOE) Office of River Protection (ORP) reaching a decision to proceed with engineering, procurement, and construction activities for the PTF. One of the issues is Technical Issue T1 - Hydrogen Gas Release from Vessels (hereafter referred to as T1). The focus of T1 is identifying controls for hydrogen release and completing any testing required to close the technical issue. In advance of selecting specific controls for hydrogen gas safety, a number of preliminary technical studies were initiated to support anticipated future testing and to improve the understanding of hydrogen gas generation, retention, and release within PTF vessels. These activities supported the development of a plan defining an overall strategy and approach for addressing T1 and achieving technical endpoints identified for T1. Preliminary studies also supported the development of a test plan for conducting testing and analysis to support closing T1. Both of these plans were developed in advance of selecting specific controls, and in the course of working on T1 it was decided that the testing and analysis identified in the test plan were not immediately needed. However, planning activities and preliminary studies led to significant technical progress in a number of areas. This report summarizes the progress to date from the preliminary technical studies. The technical results in this report should not be used for WTP design or safety and hazards analyses and technical results are marked with the following statement: “Preliminary Technical Results for Planning – Not to be used for WTP Design

  2. A simple thermodynamic model of diluted hydrogen gas/plasma for CFD applications

    NASA Astrophysics Data System (ADS)

    Quartapelle, L.; Muzzio, A.

    2015-06-01

    This work describes a simple thermodynamic model of the hydrogen gas at low densities and for temperatures going from those involving quantum rotations of ortho- and para-hydrogen up to the fully ionized state. The closed-form energy levels of Morse rotating oscillator given [D.C. Harris, M.D. Bertolucci, Symmetry and Spectroscopy (Dover, New York, 1989)] (but not those in Morse's original paper) are shown to provide an internal partition function of H2 that is a sufficiently accurate representation of that exploiting the state-of-the-art spectrum of roto-vibrational levels calculated by Pachucki and Komasa [K. Pachucki, J. Komasa, J. Chem. Phys. 130, 164113 (2009)]. A system of two coupled quadratic equations for molecular dissociation and atomic ionization at thermodynamical and chemical equilibrium is derived according to the statistical mechanics by assuming that the system is an ideal mixture containing molecules, neutral atoms and noninteracting protons and electrons. The system of two equations reduces to a single quartic equation for the ionization unknown, with the coefficients dependent on the temperature and the specific volume. Explicit relations for specific energy and entropy of the hydrogen ideal gas/plasma model are derived. These fully compatible equations of state provide a complete thermodynamic description of the system, uniformly valid from low temperatures up to a fully ionized state, with electrons and ions relaxed to one and the same temperature. The comparison with results of other models developed in the framework of the physical and chemical pictures shows that the proposed elementary model is adequate for computational fluid dynamics purposes, in applications with the hydrogen gas under diluted conditions and when the dissociation and ionization can be assumed at thermodynamical and chemical equilibrium.

  3. Design and Analysis of a Getter-Based Vacuum Pumping System for a Rocket-Borne Mass Spectrometer

    NASA Astrophysics Data System (ADS)

    Everett, E. A.; Syrstad, E. A.; Dyer, J. S.

    2010-12-01

    capacity under a variety of gas loads and experimental conditions. Additionally, rigorous modeling has been performed to simulate the gas load and performance of the instrument in the MLT. The Direct Simulation Monte Carlo (DSMC) method was used to simulate gas flow characteristics at various altitudes, from 70 to 110 km, for representative rocket trajectories. These simulations show the effects of high-speed rocket flight through the atmosphere, including the density and temperature enhancements due to the bow shock at the front of the instrument. Vacuum pumping analysis has also been performed using traditional gas flow equations, for comparison to DSMC results. The HT-TOF-MS uses a commercial MCP designed to operate at significantly greater pressures than typical fast charge-amplifying detectors. We present experimental data for MCP operation at high pressures for a variety of gases. Preliminary data indicates this detector will provide stable operation at the pressures provided by the tube getters. The combination of high-pressure MCP and getter-based vacuum pumping system will allow mass spectrometers and other MCP-based instruments to be deployed in the MLT region on future sounding rocket campaigns.

  4. Thermal decomposition of Ti getter films from the DITE tokamak

    SciTech Connect

    Malinowski, M.E.

    1981-04-01

    The potential application of Ti gettering in tritium-using tokamaks will result in unacceptably high in-torus tritium inventories if the tritium cannot be recovered from the Ti thin films. To help assess the feasibility of tritium recovery by outgassing such films, several samples of getter films evaporated in the DITE tokamak were thermally decomposed in vacuum. Film samples from four different azimuthal torus positions were heated at approx.1/sup 0/C s/sup -1/ and all exhibited decomposition rate peaks at 410/sup 0/ +- 10/sup 0/C; every film had been fully decomposed by the time 475/sup 0/C was reached. Separate experiments showed that isothermal desorption at temperatures as low as 350/sup 0/C was sufficient to outgas such films in 10 min. Together with previous work on clean films, the present results indicated that films which have not been as heavily contaminated as the DITE samples could be desorbed in vacuum at temperatures between 250--350/sup 0/C in acceptably short times, and demonstrate that in situ outgassing of tritided films would be feasible.

  5. On the use of manned hydrogen-gas ballooning in boundary layer studies.

    PubMed

    Rappenglück, B; Reitmayer, H; Fabian, P

    2000-01-01

    Measurements of nitrogen dioxide, ozone and, for the first time, on-line, nonmethane hydrocarbons with a quasicontinuous gaschromatographic/flame ionization technique were performed on a manned hydrogen-gas balloon platform. A cycle time of 10 min allowed the determination of nonmethane hydrocarbons in the carbon number range of C(4)-C(10) with a detection limit of 10 pptv. In addition, meteorological parameters (atmospheric pressure, temperature, humidity) along with GPS-data (global positioning system) was accomplished during the balloon flights. Balloon measurements of trace compounds provide valuable information about photochemical processes in the boundary layer since gas ballooning offers the only technique that stays in the same air parcel along Langrangian trajectories. In addition, gas ballooning represents a unique tool to elucidate micrometeorological observations such as atmospheric stability oscillations and local wind fields.

  6. Tensile Properties and Swelling Behavior of Sealing Rubber Materials Exposed to High-Pressure Hydrogen Gas

    NASA Astrophysics Data System (ADS)

    Yamabe, Junichiro; Nishimura, Shin

    Rubber O-rings exposed to high-pressure hydrogen gas swell, and the volume increase induced by swelling influences tensile properties of the O-rings. Samples of nonfilled (NF), carbon black-filled (CB), and silica-filled (SC) sulfur-vulcanized acrylonitrile-butadiene rubber were exposed to hydrogen at 30 °C and pressures of up to 100 MPa, and the effect of hydrogen exposure on the volume increase, hydrogen content, and tensile properties was investigated. The residual hydrogen content, measured 35 minutes after decompression, increased with increasing hydrogen pressure in the range 0.7-100 MPa for all three samples. In contrast, the volumes of NF, CB, and SC barely changed at pressures below 10 MPa, whereas they increased at pressures above 10 MPa. This nonlinear volume increase is probably related to the free volume of the rubber structure. The volume increase of the CB and SC samples was smaller than that of the NF samples, possibly because of the superior tensile properties of CB and SC. As the volumes of the NF, CB, and SC samples increased, their tensile elastic moduli decreased as a result of a decrease in crosslink density and elongation by volume increase. Although the true fracture stress of NF was barely dependent on the volume of the specimen, those of CB and SC clearly decreased as the volume increased. The decrease in the true fracture stress of CB and SC was related to the volume increase by swelling, showing that the boundary structure between the filler and the rubber matrix was changed by the volume increase.

  7. Evaluation of Technical Feasibility of Homogeneous Charge Compression Ignition (HCCI) Engine Fueled with Hydrogen, Natural Gas, and DME

    SciTech Connect

    John Pratapas; Daniel Mather; Anton Kozlovsky

    2007-03-31

    The objective of the proposed project was to confirm the feasibility of using blends of hydrogen and natural gas to improve the performance, efficiency, controllability and emissions of a homogeneous charge compression ignition (HCCI) engine. The project team utilized both engine simulation and laboratory testing to evaluate and optimize how blends of hydrogen and natural gas fuel might improve control of HCCI combustion. GTI utilized a state-of-the art single-cylinder engine test platform for the experimental work in the project. The testing was designed to evaluate the feasibility of extending the limits of HCCI engine performance (i.e., stable combustion, high efficiency and low emissions) on natural gas by using blends of natural gas and hydrogen. Early in the project Ricardo provided technical support to GTI as we applied their engine performance simulation program, WAVE, to our HCCI research engine. Modeling support was later provided by Digital Engines, LLC to use their proprietary model to predict peak pressures and temperatures for varying operating parameters included in the Design of Experiments test plan. Digital Engines also provided testing support for the hydrogen and natural gas blends. Prof. David Foster of University of Wisconsin-Madison participated early in the project by providing technical guidance on HCCI engine test plans and modeling requirements. The main purpose of the testing was to quantify the effects of hydrogen addition to natural gas HCCI. Directly comparing straight natural gas with the hydrogen enhanced test points is difficult due to the complexity of HCCI combustion. With the same air flow rate and lambda, the hydrogen enriched fuel mass flow rate is lower than the straight natural gas mass flow rate. However, the energy flow rate is higher for the hydrogen enriched fuel due to hydrogen's significantly greater lower heating value, 120 mJ/kg for hydrogen compared to 45 mJ/kg for natural gas. With these caveats in mind, an

  8. Microbial electrodialysis cell for simultaneous water desalination and hydrogen gas production.

    PubMed

    Mehanna, Maha; Kiely, Patrick D; Call, Douglas F; Logan, Bruce E

    2010-12-15

    A new approach to water desalination is to use exoelectrogenic bacteria to generate electrical power from the biodegradation of organic matter, moving charged ions from a middle chamber between two membranes in a type of microbial fuel cell called a microbial desalination cell. Desalination efficiency using this approach is limited by the voltage produced by the bacteria. Here we examine an alternative strategy based on boosting the voltage produced by the bacteria to achieve hydrogen gas evolution from the cathode using a three-chambered system we refer to as a microbial electrodialysis cell (MEDC). We examined the use of the MEDC process using two different initial NaCl concentrations of 5 g/L and 20 g/L. Conductivity in the desalination chamber was reduced by up to 68 ± 3% in a single fed-batch cycle, with electrical energy efficiencies reaching 231 ± 59%, and maximum hydrogen production rates of 0.16 ± 0.05 m(3) H(2)/m(3) d obtained at an applied voltage of 0.55 V. The advantage of this system compared to a microbial fuel cell approach is that the potentials between the electrodes can be better controlled, and the hydrogen gas that is produced can be used to recover energy to make the desalination process self-sustaining with respect to electrical power requirements.

  9. The MuCap experiment: A measurement of the muon capture rate in hydrogen gas

    SciTech Connect

    Banks, T. I.

    2007-10-26

    We have recently measured the rate of nuclear muon capture by the proton, using a novel technique which involves a time projection chamber operating in ultraclean, deuterium-depleted hydrogen gas. The target's low gas density of 1% compared to liquid hydrogen is key to avoiding uncertainties that arise from the formation of muonic molecules. The capture rate from the hyperfine singlet ground state of the {mu}p atom was obtained from the difference between the {mu}{sup -} disappearance rate in hydrogen and the world average for the {mu}{sup +} decay rate, yielding {lambda}{sub S} = 725.0{+-}17.4 s{sup -1}, from which the induced pseudoscalar coupling of the nucleon, g{sub P}(q{sup 2} = 0.88m{sub {mu}}{sup 2}) = 7.3{+-}1.1, is extracted. This result is consistent with theoretical predictions for g{sub P} that are based on the approximate chiral symmetry of QCD.

  10. Two-dimensional gas chromatography-online hydrogenation for improved characterization of petrochemical samples.

    PubMed

    Potgieter, H; Bekker, R; Govender, A; Rohwer, E

    2016-05-01

    The Fischer-Tropsch (FT) process produces a variety of hydrocarbons over a wide carbon number range and during subsequent product workup a large variety of synthetic fuels and chemicals are produced. The complexity of the product slate obtained from this process is well documented and the high temperature FT (HT-FT) process products are spread over gas, oil and water phases. The characterization of these phases is very challenging even when using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-TOFMS). Despite the increase in separation power, peak co-elution still occurs when samples containing isomeric compounds are analysed by comprehensive two dimensional GC. The separation of isomeric compounds with the same double bond equivalents is especially difficult since these compounds elute in a similar position on the GC×GC chromatogram and have identical molecular masses and similar fragmentation patterns in their electron ionization (EI) mass spectra. On-line hydrogenation after GC×GC separation is a possible way to distinguish between these isomeric compounds since the number of rings and alkene double bonds can be determined from the mass spectra of the compounds before and after hydrogenation. This paper describes development of a GC×GC method with post column hydrogenation for the determination of the backbone of cyclic/olefinic structures enabling us to differentiate between classes like dienes and cyclic olefins in complex petrochemical streams.

  11. Catalytic hydrogenation and gas permeation properties of metal-containing poly(phenylene oxide) and polysulfone

    SciTech Connect

    Hanrong Gao; Yun Xu; Shijian Liao; Ren Liu; Daorong Yu . Dalian Inst. of Chemical Physics)

    1993-11-10

    Metal-containing polymers, PPL-DPP-Pd, PPO-CPA-Pd, PSF-DPP-Pd, PSF-CPA-Pd (PDD = diphenylphosphinyl, CPA = o-carboxy phenyl amino), PPO-M (M = Pd,Cu,Co,Ni), and PSF-Pd, were prepared by incorporating metal chloride with either modified or unmodified poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and polysulfone (PSF). The Pd-containing polymers exhibit catalytic activity in the hydrogenation of cyclopentadiene under mild conditions both in alcohol solution and in the gas phase. The selectivity in the hydrogenation of diene to monoene in the gas phase can be controlled by adjusting the hydrogen partial pressure. The metal-containing polymers, PPL-M and PSF-Pd, can be cast easily into the membranes. The H[sub 2]/N[sub 2] permselectivity for PPO-M is higher than that for unmodified PPO, whereas the permeability of H[sub 2] changes slightly. The H[sub 2] permeability and H[sub 2]/N[sub 2] permselectivity for the PPO-Pd membrane are up to 67.5 barrers and 135, respectively.

  12. Dissolution of Uranium Metal Without Hydride Formation or Hydrogen Gas Generation

    SciTech Connect

    Soderquist, Chuck Z.; Oliver, Brian M.; McNamara, Bruce K.

    2008-09-01

    This study shows that metallic uranium will cleanly dissolve in carbonate-peroxide solution without generation of hydrogen gas or uranium hydride. Metallic uranium shot, 0.5 to 1 mm diameter, were reacted with ammonium carbonate - hydrogen peroxide solution ranging in concentration from 0.13M to 1.0M carbonate and 0.50M to 2.0M peroxide. The uranium beads were weighed before and after reacting with the etch solution, and from the weights of the beads, their diameters were calculated, before and after the etch. The etch rate on the beads was then calculated from the reduction in bead diameter, and independently by uranium analysis of the solution. The calculated etch rate ranged from about 4 x 10-4 to 8 x 10-4 cm per hour, dependent primarily on the peroxide concentration. A hydrogen analysis of the etched beads showed that no detectable hydrogen was introduced into the uranium metal by the etching process.

  13. Self assembled molecular monolayers on high surface area materials as molecular getters

    DOEpatents

    King, D.E.; Herdt, G.C.; Czanderna, A.W.

    1997-01-07

    The present invention relates to a gettering material that may be used as a filtration medium to remove pollutants from the environment. The gettering material comprises a high surface area material having a metal surface that chemically bonds n-alkanethiols in an organized manner thereby forming a molecular monolayer over the metal surface. The n-alkanethiols have a free functional group that interacts with the environment thereby binding specific pollutants that may be present. The gettering material may be exposed to streams of air in heating, ventilation, and air conditioning systems or streams of water to remove specific pollutants from either medium. 9 figs.

  14. Self assembled molecular monolayers on high surface area materials as molecular getters

    DOEpatents

    King, David E.; Herdt, Gregory C.; Czanderna, Alvin W.

    1997-01-01

    The present invention relates to a gettering material that may be used as a filtration medium to remove pollutants from the environment. The gettering material comprises a high surface area material having a metal surface that chemically bonds n-alkanethiols in an organized manner thereby forming a molecular monolayer over the metal surface. The n-alkanethiols have a free functional group that interacts with the environment thereby binding specific pollutants that may be present. The gettering material may be exposed to streams of air in heating, ventilation, and air conditioning systems or streams of water to remove specific pollutants from either medium.

  15. Contamination Effects of Getter Ion and Titanium Sublimation Pumped Systems on Optical Surfaces

    NASA Technical Reports Server (NTRS)

    Visentine, James T.; Richmond, Robert G.

    1973-01-01

    Previous studies have indicated that ultraclean vacuum can be produced when titanium sublimation pumps are used in conjunction with getter-ion pumps. Experiments are described in which the degrees of cleanliness of a typical getter-ion, titanium sublimation-pumped system were monitored by measuring the effects of surface contamination on the reflectance of evaporated vacuum ultraviolet mirrors. Results are presented which indicate that severe reflectance losses occurred when startup of a getter-ion pump was initiated at too high a chamber pressure. Significant reflectance losses also occurred as a result of titanium sublimation-pump operation. These data are reviewed and recommendations for improved system performance are presented.

  16. Gas pump with movable gas pumping panels

    DOEpatents

    Osher, J.L.

    Apparatus for pumping gas continuously a plurality of articulated panels of getter material, each of which absorbs gases on one side while another of its sides is simultaneously reactivated in a zone isolated by the panels themselves from a working space being pumped.

  17. Composition surveys of test gas produced by a hydrogen-oxygen-air burner. [for supersonic ramjet engine

    NASA Technical Reports Server (NTRS)

    Eggers, J. M.

    1974-01-01

    As a result of the need for a uniform hot gas test stream for fuel injector development for hydrogen fueled supersonic combustion ramjet engines, an experimental study of injector configuration effect on exit flow uniformity of a hydrogen fueled oxygen replenished, combustion burner was made. Measurements used to investigate the burner nozzle exit profiles were pitot and gas sample measurements. Gas composition and associated temperature profiles were reduced to an acceptable level by burner injector modifications. The effect of the injector modifications was to redistribute the hydrogen fuel, increase the air pressure drop, promote premixing of the oxygen and air, and establish a uniform flow pattern where the oxygen-air mixture comes into contact with the hydrogen fuel. The most sensitive phenomenon which affected the composition profiles was the uniformity of the air distribution supplied to the combustion chamber.

  18. The Effects of Added Hydrogen on Noble Gas Discharges Used as Ambient Desorption/Ionization Sources for Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Ellis, Wade C.; Lewis, Charlotte R.; Openshaw, Anna P.; Farnsworth, Paul B.

    2016-09-01

    We demonstrate the effectiveness of using hydrogen-doped argon as the support gas for the dielectric barrier discharge (DBD) ambient desorption/ionization (ADI) source in mass spectrometry. Also, we explore the chemistry responsible for the signal enhancement observed when using both hydrogen-doped argon and hydrogen-doped helium. The hydrogen-doped argon was tested for five analytes representing different classes of molecules. Addition of hydrogen to the argon plasma gas enhanced signals for gas-phase analytes and for analytes coated onto glass slides in positive and negative ion mode. The enhancements ranged from factors of 4 to 5 for gas-phase analytes and factors of 2 to 40 for coated slides. There was no significant increase in the background. The limit of detection for caffeine was lowered by a factor of 79 using H2/Ar and 2 using H2/He. Results are shown that help explain the fundamental differences between the pure-gas discharges and those that are hydrogen-doped for both argon and helium. Experiments with different discharge geometries and grounding schemes indicate that observed signal enhancements are strongly dependent on discharge configuration.

  19. The Effects of Added Hydrogen on Noble Gas Discharges Used as Ambient Desorption/Ionization Sources for Mass Spectrometry.

    PubMed

    Ellis, Wade C; Lewis, Charlotte R; Openshaw, Anna P; Farnsworth, Paul B

    2016-09-01

    We demonstrate the effectiveness of using hydrogen-doped argon as the support gas for the dielectric barrier discharge (DBD) ambient desorption/ionization (ADI) source in mass spectrometry. Also, we explore the chemistry responsible for the signal enhancement observed when using both hydrogen-doped argon and hydrogen-doped helium. The hydrogen-doped argon was tested for five analytes representing different classes of molecules. Addition of hydrogen to the argon plasma gas enhanced signals for gas-phase analytes and for analytes coated onto glass slides in positive and negative ion mode. The enhancements ranged from factors of 4 to 5 for gas-phase analytes and factors of 2 to 40 for coated slides. There was no significant increase in the background. The limit of detection for caffeine was lowered by a factor of 79 using H2/Ar and 2 using H2/He. Results are shown that help explain the fundamental differences between the pure-gas discharges and those that are hydrogen-doped for both argon and helium. Experiments with different discharge geometries and grounding schemes indicate that observed signal enhancements are strongly dependent on discharge configuration. Graphical Abstract ᅟ. PMID:27380389

  20. Flower-like Palladium Nanoclusters Decorated Graphene Electrodes for Ultrasensitive and Flexible Hydrogen Gas Sensing

    PubMed Central

    Shin, Dong Hoon; Lee, Jun Seop; Jun, Jaemoon; An, Ji Hyun; Kim, Sung Gun; Cho, Kyung Hee; Jang, Jyongsik

    2015-01-01

    Flower-like palladium nanoclusters (FPNCs) are electrodeposited onto graphene electrode that are prepared by chemical vapor deposition (CVD). The CVD graphene layer is transferred onto a poly(ethylene naphthalate) (PEN) film to provide a mechanical stability and flexibility. The surface of the CVD graphene is functionalized with diaminonaphthalene (DAN) to form flower shapes. Palladium nanoparticles act as templates to mediate the formation of FPNCs, which increase in size with reaction time. The population of FPNCs can be controlled by adjusting the DAN concentration as functionalization solution. These FPNCs_CG electrodes are sensitive to hydrogen gas at room temperature. The sensitivity and response time as a function of the FPNCs population are investigated, resulted in improved performance with increasing population. Furthermore, the minimum detectable level (MDL) of hydrogen is 0.1 ppm, which is at least 2 orders of magnitude lower than that of chemical sensors based on other Pd-based hybrid materials. PMID:26198416

  1. The gas-phase hydrogen-bonded complex between ozone and hydroperoxyl radical. A theoretical study.

    PubMed

    Mansergas, Alex; Anglada, Josep M

    2007-02-01

    We report a theoretical study on the gas-phase hydrogen-bonded complexes formed between ozone and hydroperoxyl radical, which are of interest in atmospheric chemistry. We have employed CASSCF, CASPT2, QCISD, and CCSD(T) theoretical approaches employing 6-311+G(2df,2p) and aug-cc-pVTZ basis sets, and we have found three complexes whose stabilities are computed to be 2.02, 1.19, and 1.34 kcal/mol, respectively, at 0 K. In addition, we have also found three transition states connecting these complexes that lie below the energy of the separate reactants. To help for possible experimental identification of these hydrogen-bonded complexes, we report also the computed harmonic vibrational frequencies along with the frequency shifts of the complexes, relative to the monomers, and the computed rotational constants. PMID:17266240

  2. Self-dynamics of hydrogen gas as probed by means of inelastic neutron scattering

    NASA Astrophysics Data System (ADS)

    Guarini, Eleonora; Orecchini, Andrea; Formisano, Ferdinando; Demmel, Franz; Petrillo, Caterina; Sacchetti, Francesco; Bafile, Ubaldo; Barocchi, Fabrizio

    2005-12-01

    The neutron double-differential cross-section of molecular hydrogen at low density has been measured at two rather low scattering angles and different final neutron energies by means of three-axis spectrometry. This first inelastic scattering determination of the single-particle roto-translational dynamics of room temperature H2 allows for a detailed test of the theoretical modelling of the spectral line-shapes of such a fundamental molecule, performed by referring both to a careful quantum-mechanical treatment and to a simpler semi-classical approximation. A comprehensive report on the neutron measurements and data analysis is presented, along with an overview of the theories used for comparison with the experimental results. An encouraging picture of the present capabilities in the calculation of the true dynamic response of hydrogen gas to slow and thermal neutrons is obtained, opening new perspectives for accurate data calibration in inelastic neutron spectroscopy, with special relevance for small-angle experiments.

  3. Durable regenerable sorbent pellets for removal of hydrogen sulfide from coal gas

    SciTech Connect

    Siriwardane, R.V.

    1995-12-31

    Pellets for removing hydrogen sulfide from a coal gasification stream at an elevated temperature are presented in durable form, usable over repeated cycles of absorption and regeneration. The pellets include a material reactive with hydrogen sulfide, in particular zinc oxide, a binder, and an inert material, in particular calcium sulfate (Drierite), having a particle size substantially larger than other components of the pellets. A second inert material and a promoter may also be included. Preparation of the pellets may be carried out by dry, solid-state mixing of components, moistening the mixture, and agglomerating it into pellets, followed by drying and calcining. Pellet size is selected, depending on the type of reaction bed for which the pellets are intended. The use of inert material with a large particle size provides a stable pellet structure with increased porosity, enabling effective gas contact and prolonged mechanical durability.

  4. Reduction of gaseous pollutant emissions from gas turbine combustors using hydrogen-enriched jet fuel

    NASA Technical Reports Server (NTRS)

    Clayton, R. M.

    1976-01-01

    Recent progress in an evaluation of the applicability of the hydrogen enrichment concept to achieve ultralow gaseous pollutant emission from gas turbine combustion systems is described. The target emission indexes for the program are 1.0 for oxides of nitrogen and carbon monoxide, and 0.5 for unburned hydrocarbons. The basic concept utilizes premixed molecular hydrogen, conventional jet fuel, and air to depress the lean flammability limit of the mixed fuel. This is shown to permit very lean combustion with its low NOx production while simulataneously providing an increased flame stability margin with which to maintain low CO and HC emission. Experimental emission characteristics and selected analytical results are presented for a cylindrical research combustor designed for operation with inlet-air state conditions typical for a 30:1 compression ratio, high bypass ratio, turbofan commercial engine.

  5. Measurement of Fatigue Crack Growth Relationships in Hydrogen Gas for Pressure Swing Adsorber Vessel Steels

    SciTech Connect

    Somerday, Brian P.; Barney, Monica

    2014-12-04

    We measured the hydrogen-assisted fatigue crack growth rates (da/dN) for SA516 Grade 70 steel as a function of stress-intensity factor range (ΔK) and load-cycle frequency to provide life-prediction data relevant to pressure swing adsorber (PSA) vessels. For ΔK values up to 18.5 MPa m1/2, the baseline da/dN versus ΔK relationship measured at 1Hz in 2.8 MPa hydrogen gas represents an upper bound with respect to crack growth rates measured at lower frequency. However, at higher ΔK values, we found that the baseline da/dN data had to be corrected to account for modestly higher crack growth rates at the lower frequencies relevant to PSA vessel operation.

  6. Measurement of Fatigue Crack Growth Relationships in Hydrogen Gas for Pressure Swing Adsorber Vessel Steels

    DOE PAGES

    Somerday, Brian P.; Barney, Monica

    2014-12-04

    We measured the hydrogen-assisted fatigue crack growth rates (da/dN) for SA516 Grade 70 steel as a function of stress-intensity factor range (ΔK) and load-cycle frequency to provide life-prediction data relevant to pressure swing adsorber (PSA) vessels. For ΔK values up to 18.5 MPa m1/2, the baseline da/dN versus ΔK relationship measured at 1Hz in 2.8 MPa hydrogen gas represents an upper bound with respect to crack growth rates measured at lower frequency. However, at higher ΔK values, we found that the baseline da/dN data had to be corrected to account for modestly higher crack growth rates at the lower frequenciesmore » relevant to PSA vessel operation.« less

  7. Reversible Storage of Hydrogen and Natural Gas in Nanospace-Engineered Activated Carbons

    NASA Astrophysics Data System (ADS)

    Romanos, Jimmy; Beckner, Matt; Rash, Tyler; Yu, Ping; Suppes, Galen; Pfeifer, Peter

    2012-02-01

    An overview is given of the development of advanced nanoporous carbons as storage materials for natural gas (methane) and molecular hydrogen in on-board fuel tanks for next-generation clean automobiles. High specific surface areas, porosities, and sub-nm/supra-nm pore volumes are quantitatively selected by controlling the degree of carbon consumption and metallic potassium intercalation into the carbon lattice during the activation process. Tunable bimodal pore-size distributions of sub-nm and supra-nm pores are established by subcritical nitrogen adsorption. Optimal pore structures for gravimetric and volumetric gas storage, respectively, are presented. Methane and hydrogen adsorption isotherms up to 250 bar on monolithic and powdered activated carbons are reported and validated, using several gravimetric and volumetric instruments. Current best gravimetric and volumetric storage capacities are: 256 g CH4/kg carbon and 132 g CH4/liter carbon at 293 K and 35 bar; 26, 44, and 107 g H2/kg carbon at 303, 194, and 77 K respectively and 100 bar. Adsorbed film density, specific surface area, and binding energy are analyzed separately using the Clausius-Clapeyron equation, Langmuir model, and lattice gas models.

  8. The Integration of a Structural Water Gas Shift Catalyst with a Vanadium Alloy Hydrogen Transport Device

    SciTech Connect

    Barton, Thomas; Argyle, Morris; Popa, Tiberiu

    2009-06-30

    This project is in response to a requirement for a system that combines water gas shift technology with separation technology for coal derived synthesis gas. The justification of such a system would be improved efficiency for the overall hydrogen production. By removing hydrogen from the synthesis gas stream, the water gas shift equilibrium would force more carbon monoxide to carbon dioxide and maximize the total hydrogen produced. Additional benefit would derive from the reduction in capital cost of plant by the removal of one step in the process by integrating water gas shift with the membrane separation device. The answer turns out to be that the integration of hydrogen separation and water gas shift catalysis is possible and desirable. There are no significant roadblocks to that combination of technologies. The problem becomes one of design and selection of materials to optimize, or at least maximize performance of the two integrated steps. A goal of the project was to investigate the effects of alloying elements on the performance of vanadium membranes with respect to hydrogen flux and fabricability. Vanadium was chosen as a compromise between performance and cost. It is clear that the vanadium alloys for this application can be produced, but the approach is not simple and the results inconsistent. For any future contracts, large single batches of alloy would be obtained and rolled with larger facilities to produce the most consistent thin foils possible. Brazing was identified as a very likely choice for sealing the membranes to structural components. As alloying was beneficial to hydrogen transport, it became important to identify where those alloying elements might be detrimental to brazing. Cataloging positive and negative alloying effects was a significant portion of the initial project work on vanadium alloying. A water gas shift catalyst with ceramic like structural characteristics was the second large goal of the project. Alumina was added as a

  9. Electrochemical studies of hydrogen chloride gas in several room temperature ionic liquids: mechanism and sensing.

    PubMed

    Murugappan, Krishnan; Silvester, Debbie S

    2016-01-28

    The electrochemical behaviour of highly toxic hydrogen chloride (HCl) gas has been investigated in six room temperature ionic liquids (RTILs) containing imidazolium/pyrrolidinium cations and range of anions on a Pt microelectrode using cyclic voltammetry (CV). HCl gas exists in a dissociated form of H(+) and [HCl2](-) in RTILs. A peak corresponding to the oxidation of [HCl2](-) was observed, resulting in the formation of Cl2 and H(+). These species were reversibly reduced to H2 and Cl(-), respectively, on the cathodic CV scan. The H(+) reduction peak is also present initially when scanned only in the cathodic direction. In the RTILs with a tetrafluoroborate or hexafluorophosphate anion, CVs indicated a reaction of the RTIL with the analyte/electrogenerated products, suggesting that these RTILs might not be suitable solvents for the detection of HCl gas. This was supported by NMR spectroscopy experiments, which showed that the hexafluorophosphate ionic liquid underwent structural changes after HCl gas electrochemical experiments. The analytical utility was then studied in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][NTf2]) by utilising both peaks (oxidation of [HCl2](-) and reduction of protons) and linear calibration graphs for current vs. concentration for the two processes were obtained. The reactive behaviour of some ionic liquids clearly shows that the choice of the ionic liquid is very important if employing RTILs as solvents for HCl gas detection.

  10. Predicting Peak Hydrogen Concentrations from Spontaneous Gas Releases in Hanford Waste Tanks

    SciTech Connect

    Stewart, Charles W.; Hartley, Stacey A.; Meyer, Perry A.; Wells, Beric E.

    2005-07-15

    Buoyant displacement gas release events (BDGRE) are spontaneous gas releases that occur in a few of the Hanford radioactive waste storage tanks when gas accumulation makes the sediment layer buoyant with respect to the liquid. BDGREs are assumed to be likely if the ratio of the predicted sediment gas fraction and neutral buoyancy gas fraction, or buoyancy ratio, exceeds unity. Based on the observation that the buoyancy ratio is also an empirical indicator of BDGRE size, a new methodology is derived that formally correlates the buoyancy ratio and the peak headspace hydrogen concentration resulting from BDGREs. The available data on the six historic BDGRE tanks, AN-103, AN-104, AN-105, AW-101, SY-103, and SY-101, are studied in detail to describe both the waste state and the corresponding distribution of BDGREs. The range of applicability of the buoyancy ratio-based models is assessed based on the modeling assumptions and availability of tank data. Recommendations are given for extending the range of the models applicability.

  11. Passive dissolution of hydrogen gas into groundwater using hollow-fiber membranes.

    PubMed

    Fang, Y; Hozalski, R M; Clapp, L W; Novak, P J; Semmens, M J

    2002-08-01

    A new hollow-fiber membrane remediation system has recently been developed to passively supply groundwater with dissolved hydrogen (H2) to stimulate the biodegradation of chlorinated solvents. Understanding the mass transfer behavior of membranes under conditions of creeping flow is critical for the design of such systems. Therefore, the objectives of this research were to evaluate the gas transfer behavior of hollow-fiber membranes under conditions typical of groundwater flow and to assess the effect of membrane configuration on gas transfer performance. Membrane gas transfer was evaluated using laboratory-scale glass columns operated at low flow velocities (8.6-12,973 cm/d). H2 was supplied to the inside of the membrane fibers while water flowed on the outside and normal to the fibers (i.e. cross-flow). Membrane configuration (single fiber and fabric) and membrane spacing for the fabric modules did not affect gas transfer performance. Therefore, the results from all of the experiments were combined to obtain the following dimensionless Sherwood number (Sh) correlation expressed as a function of Reynolds number (Re) and Schmidt number (Sc): Sh = 0.824Re(0.39)Sc(0.33) (0.0004gas from clean membranes to flowing water at low Re. This correlation provides a basis for estimating the membrane surface area requirements for groundwater remediation as illustrated by a simple example.

  12. Pilot Scale Water Gas Shift - Membrane Device for Hydrogen from Coal

    SciTech Connect

    Barton, Tom

    2013-06-30

    The objectives of the project were to build pilot scale hydrogen separation systems for use in a gasification product stream. This device would demonstrate fabrication and manufacturing techniques for producing commercially ready facilities. The design was a 2 lb/day hydrogen device which included composite hydrogen separation membranes, a water gas shift monolith catalyst, and stainless steel structural components. Synkera Technologies was to prepare hydrogen separation membranes with metallic rims, and to adjust the alloy composition in their membranes to a palladium-gold composition which is sulfur resistant. Chart was to confirm their brazing technology for bonding the metallic rims of the composite membranes to their structural components and design and build the 2 lbs/day device incorporating membranes and catalysts. WRI prepared the catalysts and completed the testing of the membranes and devices on coal derived syngas. The reactor incorporated eighteen 2'' by 7'' composite palladium alloy membranes. These membranes were assembled with three stacks of three paired membranes. Initial vacuum testing and visual inspection indicated that some membranes were cracked, either in transportation or in testing. During replacement of the failed membranes, while pulling a vacuum on the back side of the membranes, folds were formed in the flexible composite membranes. In some instances these folds led to cracks, primarily at the interface between the alumina and the aluminum rim. The design of the 2 lb/day device was compromised by the lack of any membrane isolation. A leak in any membrane failed the entire device. A large number of tests were undertaken to bring the full 2 lb per day hydrogen capacity on line, but no single test lasted more than 48 hours. Subsequent tests to replace the mechanical seals with brazing have been promising, but the technology remains promising but not proven.

  13. Fluorometric method for the determination of gas-phase hydrogen peroxide

    NASA Astrophysics Data System (ADS)

    Kok, Gregory L.; Lazrus, Allan L.

    1986-12-01

    The fluorometric gas-phase hydrogen peroxide procedure is based on the technique used by Lazrus et. al. for the determination of H2O2 in the liquid phase. The analytical method utilizes the reaction of H2O2 with horseradish peroxidase and p-hydroxphenylacetic acid (POPHA) to form the fluorescent dimer of POPHA. The analytical reaction responds stoichiometrically to both H2O2 and some organic hydroperoxides. To discriminate H2O2 from organic hydroperoxides, catalase is used to preferentially destroy H2O2. Using a dual-channel flow system the H2O2 concentration is determined by difference.

  14. Fluorometric method for the determination of gas-phase hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Kok, Gregory L.; Lazrus, Allan L.

    1986-01-01

    The fluorometric gas-phase hydrogen peroxide procedure is based on the technique used by Lazrus et. al. for the determination of H2O2 in the liquid phase. The analytical method utilizes the reaction of H2O2 with horseradish peroxidase and p-hydroxphenylacetic acid (POPHA) to form the fluorescent dimer of POPHA. The analytical reaction responds stoichiometrically to both H2O2 and some organic hydroperoxides. To discriminate H2O2 from organic hydroperoxides, catalase is used to preferentially destroy H2O2. Using a dual-channel flow system the H2O2 concentration is determined by difference.

  15. Proton conduction in electrolyte made of manganese dioxide for hydrogen gas sensor

    SciTech Connect

    Koyanaka, Hideki; Ueda, Yoshikatsu; Takeuchi, K; Kolesnikov, Alexander I

    2012-01-01

    We propose a network model of oxygen-pairs to store and conduct protons on the surface of manganese dioxide with a weak covalent bond like protons stored in pressured ice. The atomic distances of oxygen-pairs were estimated between 2.57 and 2.60 angstroms in crystal structures of ramsdellite-type and lambda-type manganese dioxides by using protonated samples and inelastic neutron scattering measurements. Good properties for a hydrogen gas sensor using electrolytes made of manganese dioxides that contain such oxygen-pairs were confirmed experimentally.

  16. Hydrogen Gas Sensors Fabricated on Atomically Flat 4H-SiC Webbed Cantilevers

    NASA Technical Reports Server (NTRS)

    Neudeck, Philip G.; Spry, David J.; Trunek, Andrew J.; Evans, Laura J.; Chen, Liang-Yu; Hunter, Gary W.; Androjna, Drago

    2007-01-01

    This paper reports on initial results from the first device tested of a "second generation" Pt-SiC Schottky diode hydrogen gas sensor that: 1) resides on the top of atomically flat 4H-SiC webbed cantilevers, 2) has integrated heater resistor, and 3) is bonded and packaged. With proper selection of heater resistor and sensor diode biases, rapid detection of H2 down to concentrations of 20 ppm was achieved. A stable sensor current gain of 125 +/- 11 standard deviation was demonstrated during 250 hours of cyclic test exposures to 0.5% H2 and N2/air.

  17. Intermediate energy proton stopping power for hydrogen molecules and monoatomic helium gas

    NASA Technical Reports Server (NTRS)

    Xu, Y. J.; Khandelwal, G. S.; Wilson, J. W.

    1984-01-01

    Stopping power in the intermediate energy region (100 keV to 1 MeV) was investigated, based on the work of Lindhard and Winther, and on the local plasma model. The theory is applied to calculate stopping power of hydrogen molecules and helium gas for protons of energy ranging from 100 keV to 2.5 MeV. Agreement with the experimental data is found to be within 10 percent. Previously announced in STAR as N84-16955

  18. Work function shifts of catalytic metals under hydrogen gas visualized by terahertz chemical microscopy.

    PubMed

    Kiwa, Toshihiko; Hagiwara, Takafumi; Shinomiya, Mitsuhiro; Sakai, Kenji; Tsukada, Keiji

    2012-05-21

    Terahertz chemical microscopy (TCM) was applied to visualize the distribution of the work function shift of catalytic metals under hydrogen gas. TCM measures the chemical potential on the surface of a SiO(2)/Si/sapphire sensing plate without any contact with the plate. By controlling the bias voltage between an electrode on the SiO(2)/ surface and the Si layer, the relationship between the voltage and the THz amplitude from the sensing plate can be obtained. As a demonstration, two types of structures were fabricated on the sensing plate, and the work function shifts due to catalytic reactions were visualized.

  19. NEBULAR: Spectrum synthesis for mixed hydrogen-helium gas in ionization equilibrium

    NASA Astrophysics Data System (ADS)

    Schirmer, Mischa

    2016-08-01

    NEBULAR synthesizes the spectrum of a mixed hydrogen helium gas in collisional ionization equilibrium. It is not a spectral fitting code, but it can be used to resample a model spectrum onto the wavelength grid of a real observation. It supports a wide range of temperatures and densities. NEBULAR includes free-free, free-bound, two-photon and line emission from HI, HeI and HeII. The code will either return the composite model spectrum, or, if desired, the unrescaled atomic emission coefficients. It is written in C++ and depends on the GNU Scientific Library (GSL).

  20. Catalytic steam gasification of pig compost for hydrogen-rich gas production in a fixed bed reactor.

    PubMed

    Wang, Jingbo; Xiao, Bo; Liu, Shiming; Hu, Zhiquan; He, Piwen; Guo, Dabin; Hu, Mian; Qi, Fangjie; Luo, Siyi

    2013-04-01

    The catalytic steam gasification of pig compost (PC) for hydrogen-rich gas production was experimentally investigated in a fixed bed reactor using the developed NiO on modified dolomite (NiO/MD) catalyst. A series of experiments have been performed to explore the effects of catalyst, catalytic temperature, steam to PC ratio and PC particle size on the gas quality and yield. The results indicate that the NiO/MD catalyst could significantly eliminate the tar in the gas production and increase the hydrogen yield, and the catalyst lives a long lifetime in the PC steam gasification. Moreover, the higher catalytic temperature and smaller PC particle size can contribute to more hydrogen production and gas yield. Meanwhile, the optimal ratio of steam to PC (S/P) is found to be 1.24.

  1. Phosphorus vacancy cluster model for phosphorus diffusion gettering of metals in Si

    SciTech Connect

    Chen, Renyu; Trzynadlowski, Bart; Dunham, Scott T.

    2014-02-07

    In this work, we develop models for the gettering of metals in silicon by high phosphorus concentration. We first performed ab initio calculations to determine favorable configurations of complexes involving phosphorus and transition metals (Fe, Cu, Cr, Ni, Ti, Mo, and W). Our ab initio calculations found that the P{sub 4}V cluster, a vacancy surrounded by 4 nearest-neighbor phosphorus atoms, which is the most favorable inactive P species in heavily doped Si, strongly binds metals such as Cu, Cr, Ni, and Fe. Based on the calculated binding energies, we build continuum models to describe the P deactivation and Fe gettering processes with model parameters calibrated against experimental data. In contrast to previous models assuming metal-P{sub 1}V or metal-P{sub 2}V as the gettered species, the binding of metals to P{sub 4}V satisfactorily explains the experimentally observed strong gettering behavior at high phosphorus concentrations.

  2. Mitigation of Hydrogen Gas Generation from the Reaction of Water with Uranium Metal in K Basins Sludge

    SciTech Connect

    Sinkov, Sergey I.; Delegard, Calvin H.; Schmidt, Andrew J.

    2010-01-29

    Means to decrease the rate of hydrogen gas generation from the chemical reaction of uranium metal with water were identified by surveying the technical literature. The underlying chemistry and potential side reactions were explored by conducting 61 principal experiments. Several methods achieved significant hydrogen gas generation rate mitigation. Gas-generating side reactions from interactions of organics or sludge constituents with mitigating agents were observed. Further testing is recommended to develop deeper knowledge of the underlying chemistry and to advance the technology aturation level. Uranium metal reacts with water in K Basin sludge to form uranium hydride (UH3), uranium dioxide or uraninite (UO2), and diatomic hydrogen (H2). Mechanistic studies show that hydrogen radicals (H·) and UH3 serve as intermediates in the reaction of uranium metal with water to produce H2 and UO2. Because H2 is flammable, its release into the gas phase above K Basin sludge during sludge storage, processing, immobilization, shipment, and disposal is a concern to the safety of those operations. Findings from the technical literature and from experimental investigations with simple chemical systems (including uranium metal in water), in the presence of individual sludge simulant components, with complete sludge simulants, and with actual K Basin sludge are presented in this report. Based on the literature review and intermediate lab test results, sodium nitrate, sodium nitrite, Nochar Acid Bond N960, disodium hydrogen phosphate, and hexavalent uranium [U(VI)] were tested for their effects in decreasing the rate of hydrogen generation from the reaction of uranium metal with water. Nitrate and nitrite each were effective, decreasing hydrogen generation rates in actual sludge by factors of about 100 to 1000 when used at 0.5 molar (M) concentrations. Higher attenuation factors were achieved in tests with aqueous solutions alone. Nochar N960, a water sorbent, decreased hydrogen

  3. Assessing hafnium on hafnia as an oxygen getter

    SciTech Connect

    O'Hara, Andrew; Demkov, Alexander A.; Bersuker, Gennadi

    2014-05-14

    Hafnium dioxide or hafnia is a wide band gap dielectric used in a range of electronic applications from field effect transistors to resistive memory. In many of these applications, it is important to maintain control over oxygen stoichiometry, which can be realized in practice by using a metal layer, specifically hafnium, to getter oxygen from the adjacent dielectric. In this paper, we employ density functional theory to study the thermodynamic stability of an interface between (100)-oriented monoclinic hafnia and hafnium metal. The nudged elastic band method is used to calculate the energy barrier for migration of oxygen from the oxide to the metal. Our investigation shows that the presence of hafnium lowers the formation energy of oxygen vacancies in hafnia, but more importantly the oxidation of hafnium through the migration of oxygen from hafnia is favored energetically.

  4. Evaluation of Technical Feasibility of Homogeneous Charge Compression Ignition (HCCI) Engine Fueled with Hydrogen, Natural Gas, and DME

    SciTech Connect

    Pratapas, John; Mather, Daniel; Kozlovsky, Anton

    2013-03-31

    The objective of the proposed project was to confirm the feasibility of using blends of hydrogen and natural gas to improve the performance, efficiency, controllability and emissions of a homogeneous charge compression ignition (HCCI) engine. The project team utilized both engine simulation and laboratory testing to evaluate and optimize how blends of hydrogen and natural gas fuel might improve control of HCCI combustion. GTI utilized a state-of-the art single-cylinder engine test platform for the experimental work in the project. The testing was designed to evaluate the feasibility of extending the limits of HCCI engine performance (i.e., stable combustion, high efficiency and low emissions) on natural gas by using blends of natural gas and hydrogen. Early in the project Ricardo provided technical support to GTI as we applied their engine performance simulation program, WAVE, to our HCCI research engine. Modeling support was later provided by Digital Engines, LLC to use their proprietary model to predict peak pressures and temperatures for varying operating parameters included in the Design of Experiments test plan. Digital Engines also provided testing support for the hydrogen and natural gas blends. Prof. David Foster of University of Wisconsin-Madison participated early in the project by providing technical guidance on HCCI engine test plans and modeling requirements. The main purpose of the testing was to quantify the effects of hydrogen addition to natural gas HCCI. Directly comparing straight natural gas with the hydrogen enhanced test points is difficult due to the complexity of HCCI combustion. With the same air flow rate and lambda, the hydrogen enriched fuel mass flow rate is lower than the straight natural gas mass flow rate. However, the energy flow rate is higher for the hydrogen enriched fuel due to hydrogen’s significantly greater lower heating value, 120 mJ/kg for hydrogen compared to 45 mJ/kg for natural gas. With these caveats in mind, an

  5. Thermal detection mechanism of SiC based hydrogen resistive gas sensors

    NASA Astrophysics Data System (ADS)

    Fawcett, Timothy J.; Wolan, John T.; Lloyd Spetz, Anita; Reyes, Meralys; Saddow, Stephen E.

    2006-10-01

    Silicon carbide (SiC) resistive hydrogen gas sensors have been fabricated and tested. Planar NiCr contacts were deposited on a thin 3C-SiC epitaxial film grown on thin Si wafers bonded to polycrystalline SiC substrates. At 673K, up to a 51.75±0.04% change in sensor output current and a change in the device temperature of up to 163.1±0.4K were demonstrated in response to 100% H2 in N2. Changes in device temperature are shown to be driven by the transfer of heat from the device to the gas, giving rise to a thermal detection mechanism.

  6. Ground state of a hydrogen ion molecule immersed in an inhomogeneous electron gas

    NASA Astrophysics Data System (ADS)

    Diaz-Valdes, J.; Gutierrez, F. A.; Matamala, A. R.; Denton, C. D.; Vargas, P.; Valdes, J. E.

    2007-01-01

    In this work we have calculated the ground state energy of the hydrogen molecule, H2+, immersed in the highly inhomogeneous electron gas around a metallic surface within the local density approximation. The molecule is perturbed by the electron density of a crystalline surface of Au <1 0 0> with the internuclear axis parallel to the surface. The surface spatial electron density is calculated through a linearized band structure method (LMTO-DFT). The ground state of the molecule-ion was calculated using the Born-Oppenheimer approximation for a fixed-ion while the screening effects of the inhomogeneous electron gas are depicted by a Thomas-Fermi like electrostatic potential. We found that within our model the molecular ion dissociates at the critical distance of 2.35 a.u. from the first atomic layer of the solid.

  7. Apparatus for converting hydrocarbon fuel into hydrogen gas and carbon dioxide

    DOEpatents

    Clawson, Lawrence G.; Mitchell, William L.; Bentley, Jeffrey M.; Thijssen, Johannes H. J.

    2002-01-01

    Hydrocarbon fuel reformer 100 suitable for producing synthesis hydrogen gas from reactions with hydrocarbons fuels, oxygen, and steam. A first tube 108 has a first tube inlet 110 and a first tube outlet 112. The first tube inlet 110 is adapted for receiving a first mixture including an oxygen-containing gas and a first fuel. A partially oxidized first reaction reformate is directed out of the first tube 108 into a mixing zone 114. A second tube 116 is annularly disposed about the first tube 108 and has a second tube inlet 118 and a second tube outlet 120. The second tube inlet 118 is adapted for receiving a second mixture including steam and a second fuel. A steam reformed second reaction reformate is directed out of the second tube 116 and into the mixing zone 114. From the mixing zone 114, the first and second reaction reformates may be directed into a catalytic reforming zone 144 containing a reforming catalyst 147.

  8. Diffusive Barrier and Getter Under Waste Packages VA Reference Design Feature Evaluations

    SciTech Connect

    MacNeil, K.

    1999-05-24

    This technical document evaluates those aspects of the diffusive barrier and getter features which have the potential for enhancing the performance of the Viability Assessment Reference Design and are also directly related to the key attributes for the repository safety strategy of that design. The effects of advection, hydrodynamic dispersion, and diffusion on the radionuclide migration rates through the diffusive barrier were determined through the application of the one-dimensional, advection/dispersion/diffusion equation. The results showed that because advective flow described by the advection-dispersion equation dominates, the diffusive barrier feature alone would not be effective in retarding migration of radiocuclides. However, if the diffusive barrier were combined with one or more features that reduced the potential for advection, then transport of radionuclides would be dominated by diffusion and their migration from the EBS would be impeded. Apatite was chosen as the getter material used for this report. Two getter configurations were developed, Case 1 and Case 2. As in the evaluation of the diffusive barrier, the effects of advection, hydrodynamic dispersion, and diffusion on the migration of radionuclides through the getter are evaluated. However, in addition to these mechanisms, the one-dimensional advection/dispersion/diffusion model is modified to include the effect of sorption on radionuclide migration rates through the sorptive medium (getter). As a result of sorption, the longitudinal dispersion coefficient, and the average linear velocity are effectively reduced by the retardation factor. The retardation factor is a function of the getter material's dry bulk density, sorption coefficient and moisture content. The results of the evaluation showed that a significant delay in breakthrough through the getter can be achieved if the thickness of the getter barrier is increased.

  9. Contact formation and gettering of precipitated impurities by multiple firing during semiconductor device fabrication

    DOEpatents

    Sopori, Bhushan

    2014-05-27

    Methods for contact formation and gettering of precipitated impurities by multiple firing during semiconductor device fabrication are provided. In one embodiment, a method for fabricating an electrical semiconductor device comprises: a first step that includes gettering of impurities from a semiconductor wafer and forming a backsurface field; and a second step that includes forming a front contact for the semiconductor wafer, wherein the second step is performed after completion of the first step.

  10. Phosphorous and aluminum gettering in Silicon-Film{trademark} Product II material

    SciTech Connect

    Cotter, J.E.; Barnett, A.M.; Hall, R.B.

    1995-08-01

    Gettering processes are being developed for the Silicon-Film{trademark} Product II solar cell structure. These processes have been developed specifically for films of silicon grown on dissimilar substrates with barrier layers. Gettering with both phosphorous- and aluminum-based processing sequences has resulted in enhancement of minority carrier diffusion length. Long diffusion lengths have allowed the characterization of light trapping in thin films of silicon grown on barrier-coated substrates.

  11. Low-cycle fatigue of two austenitic alloys in hydrogen gas and air at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Jaske, C. E.; Rice, R. C.

    1976-01-01

    The low-cycle fatigue resistance of type 347 stainless steel and Hastelloy Alloy X was evaluated in constant-amplitude, strain-controlled fatigue tests conducted under continuous negative strain cycling at a constant strain rate of 0.001 per sec and at total axial strain ranges of 1.5, 3.0, and 5.0 percent in both hydrogen gas and laboratory air environments in the temperature range 538-871 C. Elevated-temperature, compressive-strain hold-time experiments were also conducted. In hydrogen, the cyclic stress-strain behavior of both materials at 538 C was characterized by appreciable cyclic hardening at all strain ranges. At 871 C neither material hardened significantly; in fact, at 5% strain range 347 steel showed continuous cyclic softening until failure. The fatigue resistance of 347 steel was slightly higher than that of Alloy X at all temperatures and strain ranges. Ten-minute compressive hold time experiments at 760 and 871 C resulted in increased fatigue lives for 347 steel and decreased fatigue lives for Alloy X. Both alloys showed slightly lower fatigue resistance in air than in hydrogen. Some fractographic and metallographic results are also given.

  12. Remote detection NMR imaging of gas phase hydrogenation in microfluidic chips.

    PubMed

    Zhivonitko, Vladimir V; Telkki, Ville-Veikko; Leppäniemi, Jarmo; Scotti, Gianmario; Franssila, Sami; Koptyug, Igor V

    2013-04-21

    The heterogeneous hydrogenation reaction of propene into propane in microreactors is studied by remote detection (RD) nuclear magnetic resonance (NMR). The reactors consist of 36 parallel microchannels (50 × 50 μm(2) cross sections) coated with a platinum catalyst. We show that RD NMR is capable of monitoring reactions with sub-millimeter spatial resolution over a field-of-view of 30 × 8 mm(2) with a steady-state time-of-flight time resolution in the tens of milliseconds range. The method enables the visualization of active zones in the reactors, and time-of-flight is used to image the flow velocity variations inside the reactor. The overall reaction yields determined by NMR varied from 10% to 50%, depending on the flow rate, temperature and length of the reaction channels. The reaction yield was highest for the channels with the lowest flow velocity. Propane T1 relaxation time in the channels, estimated by means of RD NMR images, was 270 ± 18 ms. No parahydrogen-induced polarization (PHIP) was observed in experiments carried out using parahydrogen-enriched H2, indicating fast spreading of the hydrogen atoms on the sputtered Pt surface. In spite of the low concentration of gases, RD NMR made imaging of gas phase hydrogenation of propene in microreactors feasible, and it is a highly versatile method for characterizing on-chip chemical reactions.

  13. Red soil as a regenerable sorbent for high temperature removal of hydrogen sulfide from coal gas.

    PubMed

    Ko, Tzu-Hsing; Chu, Hsin; Lin, Hsiao-Ping; Peng, Ching-Yu

    2006-08-25

    In this study, hydrogen sulfide (H(2)S) was removed from coal gas by red soil under high temperature in a fixed-bed reactor. Red soil powders were collected from the northern, center and southern of Taiwan. They were characterized by XRPD, porosity analysis and DCB chemical analysis. Results show that the greater sulfur content of LP red soils is attributed to the higher free iron oxides and suitable sulfidation temperature is around 773K. High temperature has a negative effect for use red soil as a desulfurization sorbent due to thermodynamic limitation in a reduction atmosphere. During 10 cycles of regeneration, after the first cycle the red soil remained stable with a breakthrough time between 31 and 36 min. Hydrogen adversely affects sulfidation reaction, whereas CO exhibits a positive effect due to a water-shift reaction. COS was formed during the sulfidation stage and this was attributed to the reaction of H(2)S and CO. Results of XRPD indicated that, hematite is the dominant active species in fresh red soil and iron sulfide (FeS) is a product of the reaction between hematite and hydrogen sulfide in red soils. The spinel phase FeAl(2)O(4) was found during regeneration, moreover, the amount of free iron oxides decreased after regeneration indicating the some of the free iron oxide formed a spinel phase, further reducting the overall desulfurization efficiency.

  14. Residual gas entering high density hydrogen plasma: rarefaction due to rapid heating

    NASA Astrophysics Data System (ADS)

    Den Harder, N.; Schram, D. C.; Goedheer, W. J.; De Blank, H. J.; Van de Sanden, M. C. M.; Van Rooij, G. J.

    2015-04-01

    The interaction of background molecular hydrogen with magnetized (0.4 T) high density (1-5 × 1020 m-3) low temperature (˜3 eV) hydrogen plasma was inferred from the Fulcher band emission in the linear plasma generator Pilot-PSI. In the plasma center, vibrational temperatures reached 1 eV. Rotational temperatures obtained from the Q(v = 1) branch were systematically ˜0.1 eV lower than the Q(v = 0) branch temperatures, which were in the range of 0.4-0.8 eV, typically 60% of the translational temperature (determined from the width of the same spectral lines). The latter is attributed to preferential excitation of translational degrees of freedom in collisions with ions on the timescale of their in-plasma residence time. Doppler shifts revealed co-rotation of the molecules with the plasma at an angular velocity an order of magnitude lower, confirming that the Fulcher emission connects to background molecules. A simple model estimated a factor of 90 rarefaction of the molecular density at the center of the plasma column compared to the residual gas density. Temperature and density information was combined to conclude that ion-conversion molecular assisted recombination dominates plasma recombination at a rate of 1 × 10-15 m3 s-1. The observations illustrate the general significance of rapid molecule heating in high density hydrogen plasma for estimating molecular processes and how this affects Fulcher spectroscopy.

  15. Significant Increase in Hydrogen Photoproduction Rates and Yields by Wild-Type Algae is Detected at High Photobioreactor Gas Phase Volume (Fact Sheet)

    SciTech Connect

    Not Available

    2012-07-01

    This NREL Hydrogen and Fuel Cell Technical Highlight describes how hydrogen photoproduction activity in algal cultures can be improved dramatically by increasing the gas-phase to liquid-phase volume ratio of the photobioreactor. NREL, in partnership with subcontractors from the Institute of Basic Biological Problems in Pushchino, Russia, demonstrated that the hydrogen photoproduction rate in algal cultures always decreases exponentially with increasing hydrogen partial pressure above the culture. The inhibitory effect of high hydrogen concentrations in the photobioreactor gas phase on hydrogen photoproduction by algae is significant and comparable to the effect observed with some anaerobic bacteria.

  16. Efficient Removal of Cationic and Anionic Radioactive Pollutants from Water Using Hydrotalcite-Based Getters.

    PubMed

    Bo, Arixin; Sarina, Sarina; Liu, Hongwei; Zheng, Zhanfeng; Xiao, Qi; Gu, Yuantong; Ayoko, Godwin A; Zhu, Huaiyong

    2016-06-29

    Hydrotalcite (HT)-based materials are usually applied to capture anionic pollutants in aqueous solutions. Generally considered anion exchangers, their ability to capture radioactive cations is rarely exploited. In the present work, we explored the ability of pristine and calcined HT getters to effectively capture radioactive cations (Sr(2+) and Ba(2+)) which can be securely stabilized at the getter surface. It is found that calcined HT outperforms its pristine counterpart in cation removal ability. Meanwhile, a novel anion removal mechanism targeting radioactive I(-) is demonstrated. This approach involves HT surface modification with silver species, namely, Ag2CO3 nanoparticles, which can attach firmly on HT surface by forming coherent interface. This HT-based anion getter can be further used to capture I(-) in aqueous solution. The observed I(-) uptake mechanism is distinctly different from the widely reported ion exchange mechanism of HT and much more efficient. As a result of the high local concentrations of precipitants on the getters, radioactive ions in water can be readily immobilized onto the getter surface by forming precipitates. The secured ionic pollutants can be subsequently removed from water by filtration or sedimentation for safe disposal. Overall, these stable, inexpensive getters are the materials of choice for removal of trace ionic pollutants from bulk radioactive liquids, especially during episodic environmental crisis.

  17. Use of an accelerometer and a microphone as gas detectors in the online quantitative detection of hydrogen released from ammonia borane by gas chromatography.

    PubMed

    He, Yi-San; Chen, Kuan-Fu; Lin, Chien-Hung; Lin, Min-Tsung; Chen, Chien-Chung; Lin, Cheng-Huang

    2013-03-19

    The use of an accelerometer as a gas detector in gas chromatography (GC) is described for the first time. A milli-whistle was connected to the outlet of the GC capillary. When the eluted and GC carrier gases pass through the capillary and milli-whistle, a sound is produced. After a fast Fourier transform (FFT), the sound wave generated from the milli-whistle is picked up by a microphone and the resulting vibration of the milli-whistle body can be recorded by an accelerometer. The release of hydrogen gas, as the result of thermal energy, from ammonia borane (NH3BH3), which has been suggested as a storage medium for hydrogen, was selected as the model sample. The findings show that the frequencies generated, either by sound or by the vibration from the whistle body, were identical. The concentration levels of the released hydrogen gas can be determined online, based on the frequency changes. Ammonia borane was placed in a brass reservoir, heated continually, and the released hydrogen gas was directly injected into the GC inlet at 0.5 min intervals, using a home-built electromagnetic pulse injector. The concentration of hydrogen for each injection can be calculated immediately. When the ammonia borane was encapsulated within a polycarbonate (PC) microtube array membrane, the temperature required for the release of hydrogen can be decreased, which would make such a material more convenient for use. The findings indicate that 1.0 mg of ammonia borane can produce hydrogen in the range of 1.0-1.25 mL, in the temperature range of 85-115 °C.

  18. Infrared spectroscopy of hydrogen-bonded CHCl3-SO2 in the gas phase

    NASA Astrophysics Data System (ADS)

    Chung, Susan; Hippler, Michael

    2006-06-01

    A molecular association between chloroform and sulfur dioxide in the gas phase at room temperature was studied by Fourier transform infrared spectroscopy. Since the intensity of the CH-stretching fundamental vibration of monomer chloroform is very weak but much stronger upon complexation, a simple subtraction procedure isolated the CH-stretching vibration spectrum of the complex. The presence of a 1:1 complex was confirmed by two dilution series, where the monomer concentrations were varied. The molecular association manifested itself as a shift of the peak absorbance of the CH-stretching vibration of CHCl3-SO2 by +7cm-1 and of the CD-stretching vibration of CDCl3-SO2 by +5cm-1 to higher wave numbers compared to monomer chloroform, accompanied by a considerable broadening of the band contour. In agreement with previous ab initio calculations, this indicates a "blueshifting" or more appropriately, a "C-H contracting" hydrogen bond between chloroform and sulfur dioxide. An estimate of the complex concentration was made based on ab initio calculations for the integrated band strength and the measured spectrum. With this estimate, the equilibrium constant Kp (295K )=0.014 (po=105Pa) for the dimerization was calculated, providing one of the very few cases where the formation of a hydrogen-bonded gas phase complex at room temperature could be quantitatively studied by infrared spectroscopy.

  19. [Performance of an innovative polyethylene carrier biotrickling filter treating hydrogen sulphide gas].

    PubMed

    Wu, Yong-gang; Ren, Hong-qiang; Ding, Li-li

    2010-07-01

    Characteristics of double-layer biotrickling filter using high density polythene rasching rings carrier treating waste gas containing hydrogen sulphide was studied. Results showed that biotrickling filter had significant advantages of low pressure drop and even load distribution along the reactor height. When removal efficiency was greater than 90%, gas retention time was 12 s, maximum inlet load was 110 g/(m3 x h), elimination capacity was 84 g/(m3 x h). At steady state, about 37%-55% of hydrogen sulfide load was removed from the lower layer. During long-term operation, pressure drop kept to less than 280 Pa x m(-1), the backwashing period was longer than two months, no biomass accumulation happened in the lower layer, and abnormal increase in pressure drop can be used as a indicator of backwashing. Reactor recovery and restart experimental results showed that removal efficiency recovered to 95% in 1 day after 6 days without H2S, pH dramatic variation of spray liquid had significant adverse impact on biotrickling bed reactor.

  20. Hydrogen-Rich Gas Production by Cogasification of Coal and Biomass in an Intermittent Fluidized Bed

    PubMed Central

    Wang, Li-Qun; Chen, Zhao-Sheng

    2013-01-01

    This paper presents the experimental results of cogasification of coal and biomass in an intermittent fluidized bed reactor, aiming to investigate the influences of operation parameters such as gasification temperature (T), steam to biomass mass ratio (SBMR), and biomass to coal mass ratio (BCMR) on hydrogen-rich (H2-rich) gas production. The results show that H2-rich gas free of N2 dilution is produced and the H2 yield is in the range of 18.25~68.13 g/kg. The increases of T, SBMR, and BCMR are all favorable for promoting the H2 production. Higher temperature contributes to higher CO and H2 contents, as well as H2 yield. The BCMR has a weak influence on gas composition, but the yield and content of H2 increase with BCMR, reaching a peak at the BCMR of 4. The H2 content and yield in the product gas increase with SBMR, whilst the content of CO increases first and then decreases correspondingly. At a typical case, the relative linear sensitivity coefficients of H2 production efficiency to T, SBMR, and BCMR were calculated. The results reveal that the order of the influence of the operation parameters on H2 production efficiency is T > SBMR > BCMR. PMID:24174911

  1. Effect of tetraalkylammonium cations on gas coalescence at a hydrogen-evolving microelectrode.

    PubMed

    Monzon, Lorena M A; Gillen, Alice J; Mobius, Matthias E; Coey, J M D

    2015-06-01

    Hydrogen gas evolution at the surface of a microelectrode may result in periodic release of single bubbles larger than the electrode diameter. Bubbles often grow by incorporating smaller bubbles that coalesce with them. To explore the coalescence, we investigate how a series of six tetralkylammonium cations (TXA(+)), where the number of carbons on the alkyl chain varies from 1 to 6, affects the oscillatory behavior of the gas-evolving microcathode. Different concentrations of TXA(+) bromide salts ranging from a few micromolar up to 1 M were added in the acid electrolyte. The frequency of bubble release and the transition from periodic to aperiodic release are related to the inhibition of bubble coalescence and gas streaming. The concentration range where this transition occurs depends strongly on the cation hydrophobicity and it ranges from very small values for the hydrophobic cations to over 1 M for the most hydrophilic one. For some of the TXA(+) cations, the transition shows a smooth increase in release frequency before switching completely to bubble-stream behavior, while for others the transition is abrupt. A smooth increase in the gas oscillator frequency with concentration indicates that the adsorption of TXA(+) cations on the bubble surface is mass transport-limited. The inhibition of bubble coalescence by the smallest cations is electrochemically driven, facilitated by specific interactions established between the ions and the electrode surface. PMID:25970227

  2. Controlling hydrogen scrambling in multiply charged protein ions during collisional activation: implications for top-down hydrogen/deuterium exchange MS utilizing collisional activation in the gas phase.

    PubMed

    Abzalimov, Rinat R; Kaltashov, Igor A

    2010-02-01

    Hydrogen exchange in solution combined with ion fragmentation in the gas phase followed by MS detection emerged in recent years as a powerful tool to study higher order protein structure and dynamics. However, a certain type of ion chemistry in the gas phase, namely, internal rearrangement of labile hydrogen atoms (the so-called hydrogen scrambling), is often cited as a factor limiting the utility of this experimental technique. Although several studies have been carried out to elucidate the roles played by various factors in the occurrence and the extent of hydrogen scrambling, there is still no consensus as to what experimental protocol should be followed to avoid or minimize it. In this study we employ fragmentation of mass-selected subpopulations of protein ions to assess the extent of internal proton mobility prior to dissociation. A unique advantage of tandem MS is that it not only provides a means to map the deuterium content of protein ions whose overall levels of isotope incorporation can be precisely defined by controlling the mass selection window, but also correlates this spatial isotope distribution with such global characteristic as the protein ion charge state. Hydrogen scrambling does not occur when the charge state of the precursor protein ions selected for fragmentation is high. Fragment ions derived from both N- and C-terminal parts of the protein are equally unaffected by scrambling. However, spatial distribution of deuterium atoms obtained by fragmenting low-charge-density protein ions is consistent with a very high degree of scrambling prior to the dissociation events. The extent of hydrogen scrambling is also high when multistage fragmentation is used to probe deuterium incorporation locally. Taken together, the experimental results provide a coherent picture of intramolecular processes occurring prior to the dissociation event and provide guidance for the design of experiments whose outcome is unaffected by hydrogen scrambling.

  3. Application of Hydrogen Assisted Lean Operation to Natural Gas-Fueled Reciprocating Engines (HALO)

    SciTech Connect

    Chad Smutzer

    2006-01-01

    Two key challenges facing Natural Gas Engines used for cogeneration purposes are spark plug life and high NOx emissions. Using Hydrogen Assisted Lean Operation (HALO), these two keys issues are simultaneously addressed. HALO operation, as demonstrated in this project, allows stable engine operation to be achieved at ultra-lean (relative air/fuel ratios of 2) conditions, which virtually eliminates NOx production. NOx values of 10 ppm (0.07 g/bhp-hr NO) for 8% (LHV H2/LHV CH4) supplementation at an exhaust O2 level of 10% were demonstrated, which is a 98% NOx emissions reduction compared to the leanest unsupplemented operating condition. Spark ignition energy reduction (which will increase ignition system life) was carried out at an oxygen level of 9%, leading to a NOx emission level of 28 ppm (0.13 g/bhp-hr NO). The spark ignition energy reduction testing found that spark energy could be reduced 22% (from 151 mJ supplied to the coil) with 13% (LHV H2/LHV CH4) hydrogen supplementation, and even further reduced 27% with 17% hydrogen supplementation, with no reportable effect on NOx emissions for these conditions and with stable engine torque output. Another important result is that the combustion duration was shown to be only a function of hydrogen supplementation, not a function of ignition energy (until the ignitability limit was reached). The next logical step leading from these promising results is to see how much the spark energy reduction translates into increase in spark plug life, which may be accomplished by durability testing.

  4. Probing the Low-Barrier Hydrogen Bond in Hydrogen Maleate in the Gas Phase: A Photoelectron Spectroscopy and ab Initio Study

    SciTech Connect

    Woo, Hin-koon; Wang, Xue B.; Wang, Lai S.; Lau, Kai Chung

    2005-12-01

    The strength of the low-barrier hydrogen bond in hydrogen maleate in the gas phase was investigated by low-temperature photoelectron spectroscopy and ab initio calculations. Photoelectron spectra of maleic and fumaric acid monoanions (cis-/trans-HO2CCHdCHCO2 -) were obtained at low temperatures and at 193 nm photon energy. Vibrational structure was observed for trans-HO2CCHdCHCO2 - due to the OCO bending modes; however, cis-HO2CCHdCHCO2 - yielded a broad and featureless spectrum. The electron binding energy of cis-HO2CCHdCHCO2 - is about 1 eV blue-shifted relative to trans-HO2CCHdCHCO2 - due to the formation of intramolecular hydrogen bond in the cis-isomer. Theoretical calculations (CCSD(T)/ aug-cc-pVTZ and B3LYP/aug-cc-pVTZ) were carried out to estimate the strength of the intramolecular hydrogen bond in cis-HO2CCHdCHCO2 -. Combining experimental and theoretical calculations yields an estimate of 21.5 ( 2.0 kcal/mol for the intramolecular hydrogen bond strength in hydrogen maleate.

  5. Numerical modeling of gas mixing and bio-chemical transformations during underground hydrogen storage within the project H2STORE

    NASA Astrophysics Data System (ADS)

    Hagemann, B.; Feldmann, F.; Panfilov, M.; Ganzer, L.

    2015-12-01

    The change from fossil to renewable energy sources is demanding an increasing amount of storage capacities for electrical energy. A promising technological solution is the storage of hydrogen in the subsurface. Hydrogen can be produced by electrolysis using excessive electrical energy and subsequently converted back into electricity by fuel cells or engine generators. The development of this technology starts with adding small amounts of hydrogen to the high pressure natural gas grid and continues with the creation of pure underground hydrogen storages. The feasibility of hydrogen storage in depleted gas reservoirs is investigated in the lighthouse project H2STORE financed by the German Ministry for Education and Research. The joint research project has project members from the University of Jena, the Clausthal University of Technology, the GFZ Potsdam and the French National Center for Scientic Research in Nancy. The six sub projects are based on laboratory experiments, numerical simulations and analytical work which cover the investigation of mineralogical, geochemical, physio-chemical, sedimentological, microbiological and gas mixing processes in reservoir and cap rocks. The focus in this presentation is on the numerical modeling of underground hydrogen storage. A mathematical model was developed which describes the involved coupled hydrodynamic and microbiological effects. Thereby, the bio-chemical reaction rates depend on the kinetics of microbial growth which is induced by the injection of hydrogen. The model has been numerically implemented on the basis of the open source code DuMuX. A field case study based on a real German gas reservoir was performed to investigate the mixing of hydrogen with residual gases and to discover the consequences of bio-chemical reactions.

  6. Use of hydrogen as a carrier gas for the analysis of steroids with anabolic activity by gas chromatography-mass spectrometry.

    PubMed

    Muñoz-Guerra, J A; Prado, P; García-Tenorio, S Vargas

    2011-10-14

    Due to the impact in the media and the requirements of sensitivity and robustness, the detection of the misuse of forbidden substances in sports is a really challenging area for analytical chemistry, where any study focused on enhancing the performance of the analytical methods will be of great interest. The aim of the present study was to evaluate the usefulness of using hydrogen instead of helium as a carrier gas for the analysis of anabolic steroids by gas chromatography-mass spectrometry with electron ionization. There are several drawbacks related with the use of helium as a carrier gas: it is expensive, is a non-renewable resource, and has limited availability in many parts of the world. In contrast, hydrogen is readily available using a hydrogen generator or high-pressure bottled gas, and allows a faster analysis without loss of efficiency; nevertheless it should not be forgotten that due to its explosiveness hydrogen must be handled with caution. Throughout the study the impact of the change of the carrier gas will be evaluated in terms of: performance of the chromatographic system, saving of time and money, impact on the high vacuum in the analyzer, changes in the fragmentation behaviour of the analytes, and finally consequences for the limits of detection achieved with the method.

  7. Investigation of low-latitude hydrogen emission in terms of a two-component interstellar gas model

    NASA Technical Reports Server (NTRS)

    Baker, P. L.; Burton, W. B.

    1975-01-01

    High-resolution 21-cm hydrogen line observations at low galactic latitude are analyzed to determine the large-scale distribution of galactic hydrogen. Distribution parameters are found by model fitting, optical depth effects are computed using a two-component gas model suggested by the observations, and calculations are made for a one-component uniform spin-temperature gas model to show the systematic departures between this model and data obtained by incorrect treatment of the optical depth effects. Synthetic 21-cm line profiles are computed from the two-component model, and the large-scale trends of the observed emission profiles are reproduced together with the magnitude of the small-scale emission irregularities. Values are determined for the thickness of the galactic hydrogen disk between half density points, the total observed neutral hydrogen mass of the galaxy, and the central number density of the intercloud hydrogen atoms. It is shown that typical hydrogen clouds must be between 1 and 13 pc in diameter and that optical thinness exists on large-scale despite the presence of optically thin gas.

  8. Pt-Ti-O gate silicon-metal-insulator-semiconductor field-effect transistor hydrogen gas sensors in harsh environments

    NASA Astrophysics Data System (ADS)

    Usagawa, Toshiyuki; Ueda, Kazuhiro; Nambu, Akira; Yoneyama, Akio; Kikuchi, Yota; Watanabe, Atsushi

    2016-06-01

    The influence of radiation damages to developed hydrogen gas sensor chips from γ-rays (60Co) and/or X-rays (synchrotron radiation) is manageably avoided for sensor operations even at extremely high integral doses such as 1.8 and/or 18 MGy. Platinum-titanium-oxygen (Pt-Ti-O) gate silicon-metal-insulator-semiconductor field-effect transistor (Si-MISFET) hydrogen gas sensors can work stably as hydrogen sensors up to about 270 °C and also show environmental hardness as follows: When nitrogen-diluted 10-ppm hexamethyldisiloxane (HMDS) was exposed to the sensor FETs for 40 min at a working temperature of 115 °C, large sensing amplitude (ΔV g) changed little within repetition errors before and after HMDS exposures. The variations of ΔV g among relative humidity of 20 and 80% are very small within ±4.4% around 50% under 40 °C atmosphere. The Pt-Ti-O sensors have been found to show large ΔV g of 624.4 mV with σΔV g of 7.27 mV for nine times repeated measurements under nitrogen-diluted 1.0%-hydrogen gas, which are nearly the same values of 654.5 mV with σΔV g of 3.77 mV under air-diluted 1.0%-hydrogen gas.

  9. Inhalation of hydrogen gas attenuates left ventricular remodeling induced by intermittent hypoxia in mice.

    PubMed

    Hayashi, Tetsuya; Yoshioka, Toshitaka; Hasegawa, Kenichi; Miyamura, Masatoshi; Mori, Tatsuhiko; Ukimura, Akira; Matsumura, Yasuo; Ishizaka, Nobukazu

    2011-09-01

    Sleep apnea syndrome increases the risk of cardiovascular morbidity and mortality. We previously reported that intermittent hypoxia increases superoxide production in a manner dependent on nicotinamide adenine dinucleotide phosphate and accelerates adverse left ventricular (LV) remodeling. Recent studies have suggested that hydrogen (H(2)) may have an antioxidant effect by reducing hydroxyl radicals. In this study, we investigated the effects of H(2) gas inhalation on lipid metabolism and LV remodeling induced by intermittent hypoxia in mice. Male C57BL/6J mice (n = 62) were exposed to intermittent hypoxia (repetitive cycle of 1-min periods of 5 and 21% oxygen for 8 h during daytime) for 7 days. H(2) gas (1.3 vol/100 vol) was given either at the time of reoxygenation, during hypoxic conditions, or throughout the experimental period. Mice kept under normoxic conditions served as controls (n = 13). Intermittent hypoxia significantly increased plasma levels of low- and very low-density cholesterol and the amount of 4-hydroxy-2-nonenal-modified protein adducts in the LV myocardium. It also upregulated mRNA expression of tissue necrosis factor-α, interleukin-6, and brain natriuretic peptide, increased production of superoxide, and induced cardiomyocyte hypertrophy, nuclear deformity, mitochondrial degeneration, and interstitial fibrosis. H(2) gas inhalation significantly suppressed these changes induced by intermittent hypoxia. In particular, H(2) gas inhaled at the timing of reoxygenation or throughout the experiment was effective in preventing dyslipidemia and suppressing superoxide production in the LV myocardium. These results suggest that inhalation of H(2) gas was effective for reducing oxidative stress and preventing LV remodeling induced by intermittent hypoxia relevant to sleep apnea.

  10. Method And Apparatus For Converting Hydrocarbon Fuel Into Hydrogen Gas And Carbon Dioxide

    DOEpatents

    Clawson, Lawrence G.; Mitchell, William L.; Bentley, Jeffrey M.; Thijssen, Johannes H. J.

    2000-09-26

    A method is disclosed for synthesizing hydrogen gas from hydrocarbon fuel. A first mixture of steam and a first fuel is directed into a first tube 208 to subject the first mixture to a first steam reforming reaction in the presence of a first catalyst 214. A stream of oxygen-containing gas is pre-heated by transferring heat energy from product gases. A second mixture of the pre-heated oxygen-containing gas and a second fuel is directed into a second tube 218 disposed about the first tube 208 to subject the second mixture to a partial oxidation reaction and to provide heat energy for transfer to the first tube 208. A first reaction reformate from the first tube 208 and a second reaction reformate from the second tube 218 are directed into a third tube 224 disposed about the second tube 218 to subject the first and second reaction reformates to a second steam reforming reaction, wherein heat energy is transferred to the third tube 224 from the second tube 218.

  11. Highly sensitive hydrogen sulfide (H₂S) gas sensors from viral-templated nanocrystalline gold nanowires.

    PubMed

    Moon, Chung Hee; Zhang, Miluo; Myung, Nosang V; Haberer, Elaine D

    2014-04-01

    A facile, site-specific viral-templated assembly method was used to fabricate sensitive hydrogen sulfide (H2S) gas sensors at room temperature. A gold-binding M13 bacteriophage served to organize gold nanoparticles into linear arrays which were used as seeds for subsequent nanowire formation through electroless deposition. Nanowire widths and densities within the sensors were modified by electroless deposition time and phage concentration, respectively, to tune device resistance. Chemiresistive H2S gas sensors with superior room temperature sensing performance were produced with sensitivity of 654%/ppm(v), theoretical lowest detection limit of 2 ppb(v), and 70% recovery within 9 min for 0.025 ppm(v). The role of the viral template and associated gold-binding peptide was elucidated by removing organics using a short O₂ plasma treatment followed by an ethanol dip. The template and gold-binding peptide were crucial to electrical and sensor performance. Without surface organics, the resistance fell by several orders of magnitude, the sensitivity dropped by more than a factor of 100 to 6%/ppm(v), the lower limit of detection increased, and no recovery was detected with dry air flow. Viral templates provide a novel, alternative fabrication route for highly sensitive, nanostructured H2S gas sensors.

  12. Molecular hydrogen line ratios in four regions of shock-excited gas

    NASA Technical Reports Server (NTRS)

    Burton, M. G.; Brand, P. W. J. L.; Geballe, T. R.; Webster, A. S.

    1989-01-01

    Five emission lines of molecular hydrogen, with wavelengths in the ranges of 2.10-2.25 and 3.80-3.85 microns, have been observed in four objects of different type in which the line emission is believed to be excited by shocks. The relative intensities of the lines 1 - 0 S(1):1 - 0 S(O):2 - 1 S(1) are approximately 10.5:2.5:1.0 in all four objects. The 0 - 0 S(13):1 - 0 O(7) line ratio, however, varies from 1.05 in OMC-1 to about 2.3 in the Herbig-Haro object HH 7. The excitation temperature derived from the S(13) and O(7) lines is higher than that derived from the 1 - 0 and 2 - 1 S(1) lines in all four objects, so the shocked gas in these objects cannot be characterized by a single temperature. The constancy of the (1-0)/(2-1) S(1) line ratio between sources suggests that the post-shock gas is 'thermalized' in each source. The S(13)/O(7) ratio is particularly sensitive to the density and temperature conditions in the gas.

  13. Highly sensitive hydrogen sulfide (H2 S) gas sensors from viral-templated nanocrystalline gold nanowires

    NASA Astrophysics Data System (ADS)

    Moon, Chung Hee; Zhang, Miluo; Myung, Nosang V.; Haberer, Elaine D.

    2014-04-01

    A facile, site-specific viral-templated assembly method was used to fabricate sensitive hydrogen sulfide (H2S) gas sensors at room temperature. A gold-binding M13 bacteriophage served to organize gold nanoparticles into linear arrays which were used as seeds for subsequent nanowire formation through electroless deposition. Nanowire widths and densities within the sensors were modified by electroless deposition time and phage concentration, respectively, to tune device resistance. Chemiresistive H2S gas sensors with superior room temperature sensing performance were produced with sensitivity of 654%/ppmv, theoretical lowest detection limit of 2 ppbv, and 70% recovery within 9 min for 0.025 ppmv. The role of the viral template and associated gold-binding peptide was elucidated by removing organics using a short O2 plasma treatment followed by an ethanol dip. The template and gold-binding peptide were crucial to electrical and sensor performance. Without surface organics, the resistance fell by several orders of magnitude, the sensitivity dropped by more than a factor of 100 to 6%/ppmv, the lower limit of detection increased, and no recovery was detected with dry air flow. Viral templates provide a novel, alternative fabrication route for highly sensitive, nanostructured H2S gas sensors.

  14. Capture and storage of hydrogen gas by zero-valent iron.

    PubMed

    Reardon, Eric J

    2014-02-01

    Granular Fe(o), used to reductively degrade a variety of contaminants in groundwater, corrodes in water to produce H2(g). A portion enters the Fe(o) lattice where it is stored in trapping sites such as lattice defects and microcracks. The balance is dissolved by the groundwater where it may exsolve as a gas if its solubility is exceeded. Gas exsolution can reduce the effectiveness of the Fe(o) treatment zone by reducing contact of the contaminant with iron surfaces or by diverting groundwater flow. It also represents a lost electron resource that otherwise could be involved in reductive degradation of contaminants. It is advantageous to select an iron for remediation purposes that captures a large proportion of the H2(g) it generates. This study examines various aspects of the H2(g) uptake process and has found 1) H2(g) does not have to be generated at the water/iron interface to enter the lattice. It can enter directly from the gas/water phases, 2) exposure of granular sponge iron to H2(g) reduces the dormant period for the onset of iron corrosion, 3) the large quantities of H2(g) generated by nano-Fe(o) injected into a reactive barrier of an appropriate granular iron can be captured in the lattice of that iron, and 4) lattice-bound hydrogen represents an additional electron resource to Fe(o) for remediation purposes and may be accessible using physical or chemical means.

  15. Liquid-to-Gas Mass Transfer in Anaerobic Processes: Inevitable Transfer Limitations of Methane and Hydrogen in the Biomethanation Process

    PubMed Central

    Pauss, André; Andre, Gérald; Perrier, Michel; Guiot, Serge R.

    1990-01-01

    Liquid-to-gas mass transfer in anaerobic processes was investigated theoretically and experimentally. By using the classical definition of kLa, the global volumetric mass transfer coefficient, theoretical development of mass balances in such processes demonstrates that the mass transfer of highly soluble gases is not limited in the usual conditions occurring in anaerobic fermentors (low-intensity mixing). Conversely, the limitation is important for poorly soluble gases, such as methane and hydrogen. The latter could be overconcentrated to as much as 80 times the value at thermodynamic equilibrium. Such overconcentrations bring into question the biological interpretations that have been deduced solely from gaseous measurements. Experimental results obtained in three different methanogenic reactors for a wide range of conditions of mixing and gas production confirmed the general existence of low mass transfer coefficients and consequently of large overconcentrations of dissolved methane and hydrogen (up to 12 and 70 times the equilibrium values, respectively). Hydrogen mass transfer coefficients were obtained from the direct measurements of dissolved and gaseous concentrations, while carbon dioxide coefficients were calculated from gas phase composition and calculation of related dissolved concentration. Methane transfer coefficients were based on calculations from the carbon dioxide coefficients. From mass balances performed on a gas bubble during its simulated growth and ascent to the surface of the liquid, the methane and carbon dioxide contents in the gas bubble appeared to be controlled by the bubble growth process, while the bubble ascent was largely responsible for a slight enrichment in hydrogen. PMID:16348206

  16. Phosphorus diffusion gettering process of multicrystalline silicon using a sacrificial porous silicon layer

    NASA Astrophysics Data System (ADS)

    Lotfi, Derbali; Hatem, Ezzaouia

    2012-07-01

    The aims of this work are to getter undesirable impurities from low-cost multicrystalline silicon (mc-Si) wafers and then enhance their electronic properties. We used an efficient process which consists of applying phosphorus diffusion into a sacrificial porous silicon (PS) layer in which the gettered impurities have been trapped after the heat treatment. As we have expected, after removing the phosphorus-rich PS layer, the electrical properties of the mc-Si wafers were significantly improved. The PS layers, realized on both sides of the mc-Si substrates, were formed by the stain-etching technique. The phosphorus treatment was achieved using a liquid POCl3-based source on both sides of the mc-Si wafers. The realized phosphorus/PS/Si/PS/phosphorus structures were annealed at a temperature ranging between 700°C and 950°C under a controlled O2 atmosphere, which allows phosphorus to diffuse throughout the PS layers and to getter eventual metal impurities towards the phosphorus-doped PS layer. The effect of this gettering procedure was investigated by means of internal quantum efficiency and the dark current-voltage ( I- V) characteristics. The minority carrier lifetime measurements were made using a WTC-120 photoconductance lifetime tester. The serial resistance and the shunt resistance carried out from the dark I- V curves confirm this gettering-related solar cell improvement. It has been shown that the photovoltaic parameters of the gettered silicon solar cells were improved with regard to the ungettered one, which proves the beneficial effect of this gettering process on the conversion efficiency of the multicrystalline silicon solar cells.

  17. Mobile measurement of methane and hydrogen sulfide at natural gas production site fence lines in the Texas Barnett Shale.

    PubMed

    Eapi, Gautam R; Sabnis, Madhu S; Sattler, Melanie L

    2014-08-01

    Production of natural gas from shale formations is bringing drilling and production operations to regions of the United States that have seen little or no similar activity in the past, which has generated considerable interest in potential environmental impacts. This study focused on the Barnett Shale Fort Worth Basin in Texas, which saw the number of gas-producing wells grow from 726 in 2001 to 15,870 in 2011. This study aimed to measure fence line concentrations of methane and hydrogen sulfide at natural gas production sites (wells, liquid storage tanks, and associated equipment) in the four core counties of the Barnett Shale (Denton, Johnson, Tarrant, and Wise). A mobile measurement survey was conducted in the vicinity of 4788 wells near 401 lease sites, representing 35% of gas production volume, 31% of wells, and 38% of condensate production volume in the four-county core area. Methane and hydrogen sulfide concentrations were measured using a Picarro G2204 cavity ring-down spectrometer (CRDS). Since the research team did not have access to lease site interiors, measurements were made by driving on roads on the exterior of the lease sites. Over 150 hr of data were collected from March to July 2012. During two sets of drive-by measurements, it was found that 66 sites (16.5%) had methane concentrations > 3 parts per million (ppm) just beyond the fence line. Thirty-two lease sites (8.0%) had hydrogen sulfide concentrations > 4.7 parts per billion (ppb) (odor recognition threshold) just beyond the fence line. Measured concentrations generally did not correlate well with site characteristics (natural gas production volume, number of wells, or condensate production). t tests showed that for two counties, methane concentrations for dry sites were higher than those for wet sites. Follow-up study is recommended to provide more information at sites identified with high levels of methane and hydrogen sulfide. Implications: Information regarding air emissions from shale gas

  18. Mobile measurement of methane and hydrogen sulfide at natural gas production site fence lines in the Texas Barnett Shale.

    PubMed

    Eapi, Gautam R; Sabnis, Madhu S; Sattler, Melanie L

    2014-08-01

    Production of natural gas from shale formations is bringing drilling and production operations to regions of the United States that have seen little or no similar activity in the past, which has generated considerable interest in potential environmental impacts. This study focused on the Barnett Shale Fort Worth Basin in Texas, which saw the number of gas-producing wells grow from 726 in 2001 to 15,870 in 2011. This study aimed to measure fence line concentrations of methane and hydrogen sulfide at natural gas production sites (wells, liquid storage tanks, and associated equipment) in the four core counties of the Barnett Shale (Denton, Johnson, Tarrant, and Wise). A mobile measurement survey was conducted in the vicinity of 4788 wells near 401 lease sites, representing 35% of gas production volume, 31% of wells, and 38% of condensate production volume in the four-county core area. Methane and hydrogen sulfide concentrations were measured using a Picarro G2204 cavity ring-down spectrometer (CRDS). Since the research team did not have access to lease site interiors, measurements were made by driving on roads on the exterior of the lease sites. Over 150 hr of data were collected from March to July 2012. During two sets of drive-by measurements, it was found that 66 sites (16.5%) had methane concentrations > 3 parts per million (ppm) just beyond the fence line. Thirty-two lease sites (8.0%) had hydrogen sulfide concentrations > 4.7 parts per billion (ppb) (odor recognition threshold) just beyond the fence line. Measured concentrations generally did not correlate well with site characteristics (natural gas production volume, number of wells, or condensate production). t tests showed that for two counties, methane concentrations for dry sites were higher than those for wet sites. Follow-up study is recommended to provide more information at sites identified with high levels of methane and hydrogen sulfide. Implications: Information regarding air emissions from shale gas

  19. A rare case of portal vein gas: accidental hydrogen peroxide ingestion.

    PubMed

    Zengin, Suat; Al, Behcet; Genç, Sinan; Yarbil, Pinar; Yilmaz, Demet Ari; Gulsen, Murat Taner

    2012-01-01

    Hydrogen peroxide (H(2)O(2)) is a colourless and odourless liquid with oxidant characteristics used for various purposes. Whereas in lower concentrations (3%), H(2)O(2) is used as a disinfectant in home cleaning products and wound care, in higher concentrations (35%) it is used in textile and paper industry as a bleaching agent and is diluted for use in lightening hair dyes. Like other caustic substances, direct injuries may develop if H(2)O(2) is swallowed and systemic air embolisms may occur due to the resultant gaseous oxygen. This study discusses a patient who was detected with the presence of gas in the portal venous system due to H(2)O(2) intoxication and was treated conservatively.

  20. Miniaturized metal (metal alloy)/ PdO.sub.x/SiC hydrogen and hydrocarbon gas sensors

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W. (Inventor); Xu, Jennifer C. (Inventor); Lukco, Dorothy (Inventor)

    2011-01-01

    A miniaturized Schottky diode hydrogen and hydrocarbon sensor and the method of making same is disclosed and claimed. The sensor comprises a catalytic metal layer, such as palladium, a silicon carbide substrate layer and a thin barrier layer in between the catalytic and substrate layers made of palladium oxide (PdO.sub.x ). This highly stable device provides sensitive gas detection at temperatures ranging from at least 450 to 600.degree. C. The barrier layer prevents reactions between the catalytic metal layer and the substrate layer. Conventional semiconductor fabrication techniques are used to fabricate the small-sized sensors. The use of a thicker palladium oxide barrier layer for other semiconductor structures such as a capacitor and transistor structures is also disclosed.

  1. Development of a hydrogen and deuterium polarized gas target for application in storage rings

    SciTech Connect

    Haeberli, W.

    1992-02-01

    Polarized gas targets of atomic hydrogen and deuterium have significant advantages over conventional polarized targets, e.g. chemical and isotopic purity, large polarization including deuteron tensor polarization, absence of strong magnetic fields, rapid polarization reversal. While in principle the beam of polarized atoms from an atomic beam source (Stern-Gerlach spin separation) can be used as a polarized target, the target thickness achieved is too small for most applications. We propose to increase the target thickness by injecting the polarized atoms into a storage cell. Provided the atoms survive several hundred wall collisions without losing their polarization, it will be possible to achieve a target thickness of 10{sup 13} to 10{sup 14} atoms/cm{sup 2} by injection of polarized atoms from an atomic-beam source into suitable cells. Such targets are very attractive as internal targets in storage rings.

  2. Development of a hydrogen and deuterium polarized gas target for application in storage rings. Progress report

    SciTech Connect

    Haeberli, W.

    1992-02-01

    Polarized gas targets of atomic hydrogen and deuterium have significant advantages over conventional polarized targets, e.g. chemical and isotopic purity, large polarization including deuteron tensor polarization, absence of strong magnetic fields, rapid polarization reversal. While in principle the beam of polarized atoms from an atomic beam source (Stern-Gerlach spin separation) can be used as a polarized target, the target thickness achieved is too small for most applications. We propose to increase the target thickness by injecting the polarized atoms into a storage cell. Provided the atoms survive several hundred wall collisions without losing their polarization, it will be possible to achieve a target thickness of 10{sup 13} to 10{sup 14} atoms/cm{sup 2} by injection of polarized atoms from an atomic-beam source into suitable cells. Such targets are very attractive as internal targets in storage rings.

  3. Buoyancy Effects on Flow Transition in Hydrogen Gas Jet Diffusion Flames

    NASA Technical Reports Server (NTRS)

    Albers, Burt W.; Agrawal, Ajay K.; Griffin, DeVon (Technical Monitor)

    2000-01-01

    Experiments were performed in earth-gravity to determine how buoyancy affected transition from laminar to turbulent flow in hydrogen gas jet diffusion flames. The jet exit Froude number characterizing buoyancy in the flame was varied from 1.65 x 10(exp 5) to 1.14 x 10(exp 8) by varying the operating pressure and/or burner inside diameter. Laminar fuel jet was discharged vertically into ambient air flowing through a combustion chamber. Flame characteristics were observed using rainbow schlieren deflectometry, a line-of-site optical diagnostic technique. Results show that the breakpoint length for a given jet exit Reynolds number increased with increasing Froude number. Data suggest that buoyant transitional flames might become laminar in the absence of gravity. The schlieren technique was shown as effective in quantifying the flame characteristics.

  4. Miniaturized Metal (Metal Alloy)/PdO(x)/SiC Hydrogen and Hydrocarbon Gas Sensors

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W. (Inventor); Xu, Jennifer C. (Inventor); Lukco, Dorothy (Inventor)

    2008-01-01

    A miniaturized Schottky diode hydrogen and hydrocarbon sensor and the method of making same is disclosed and claimed. The sensor comprises a catalytic metal layer, such as palladium, a silicon carbide substrate layer and a thin barrier layer in between the catalytic and substrate layers made of palladium oxide (PdO(x)). This highly stable device provides sensitive gas detection at temperatures ranging from at least 450 to 600 C. The barrier layer prevents reactions between the catalytic metal layer and the substrate layer. Conventional semiconductor fabrication techniques are used to fabricate the small-sided sensors. The use of a thicker palladium oxide barrier layer for other semiconductor structures such as a capacitor and transistor structures is also disclosed.

  5. Miniaturized metal (metal alloy)/ PdO.sub.x/SiC hydrogen and hydrocarbon gas sensors

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W. (Inventor); Xu, Jennifer C. (Inventor); Lukco, Dorothy (Inventor)

    2008-01-01

    A miniaturized Schottky diode hydrogen and hydrocarbon sensor and the method of making same is disclosed and claimed. The sensor comprises a catalytic metal layer, such as palladium, a silicon carbide substrate layer and a thin barrier layer in between the catalytic and substrate layers made of palladium oxide (PdO.sub.x). This highly stable device provides sensitive gas detection at temperatures ranging from at least 450 to 600.degree. C. The barrier layer prevents reactions between the catalytic metal layer and the substrate layer. Conventional semiconductor fabrication techniques are used to fabricate the small-sized sensors. The use of a thicker palladium oxide barrier layer for other semiconductor structures such as a capacitor and transistor structures is also disclosed.

  6. An electron beam polarimeter based on scattering from a windowless, polarized hydrogen gas target

    NASA Astrophysics Data System (ADS)

    Bernauer, Jan; Milner, Richard

    2013-11-01

    Here we present the idea to develop a precision polarimeter for low energy, intense polarized electron beams using a windowless polarized hydrogen gas cell fed by an atomic beam source. This technique would use proven technology used successfully in both the electron scattering experiments: HERMES with 27 GeV electron and positron beams at DESY, and BLAST with 850 MeV electron beams at MIT-Bates. At 100 MeV beam energy, both spin-dependent Mo/ller and elastic electron-proton scattering processes have a high cross section and sizable spin asymmetries. The concept is described and estimates for realistic rates for elastic electron-proton scattering and Mo/ller scattering are presented. A number of important issues which affect the ultimate systematic uncertainty are identified.

  7. Analysis of Japanese Articles about Suicides Involving Charcoal Burning or Hydrogen Sulfide Gas

    PubMed Central

    Nabeshima, Yoshihiro; Onozuka, Daisuke; Kitazono, Takanari; Hagihara, Akihito

    2016-01-01

    It is well known that certain types of media reports about suicide can result in imitative suicides. In the last two decades, Japan has experienced two suicide epidemics and the subsequent excessive media coverage of these events. However, the quality of the media suicide reports has yet to be evaluated in terms of the guidelines for media suicide coverage. Thus, the present study analyzed Japanese newspaper articles (n = 4007) on suicides by charcoal burning or hydrogen sulfide gas between 11 February 2003 and 13 March 2010. The suicide reports were evaluated in terms of the extent to which they conformed to the suicide reporting guidelines. The mean violation scores were 3.06 (±0.7) for all articles, 3.2 (±0.8) for articles about suicide by charcoal burning, and 2.9 (±0.7) for articles about suicide by hydrogen sulfide (p < 0.001). With the exception of not following several recommendations, newspaper articles about suicide have improved in quality, as defined by the recommendations for media suicide coverage. To prevent imitative suicides based on media suicide reports, individuals in the media should try not to report suicide methods and to make attempts to report the poor condition of suicide survivors. PMID:27754453

  8. Certification Testing and Demonstration of Insulated Pressure Vessels for Vehicular Hydrogen and Natural Gas Storage

    SciTech Connect

    Aceves, S M; Martinez-Frias, J; Espinosa-Loza, F; Schaffer, R; Clapper, W

    2002-05-22

    We are working on developing an alternative technology for storage of hydrogen or natural gas on light-duty vehicles. This technology has been titled insulated pressure vessels. Insulated pressure vessels are cryogenic-capable pressure vessels that can accept either liquid fuel or ambient-temperature compressed fuel. Insulated pressure vessels offer the advantages of cryogenic liquid fuel tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for fuel liquefaction and reduced evaporative losses). The work described in this paper is directed at verifying that commercially available pressure vessels can be safely used to store liquid hydrogen or LNG. The use of commercially available pressure vessels significantly reduces the cost and complexity of the insulated pressure vessel development effort. This paper describes a series of tests that have been done with aluminum-lined, fiber-wrapped vessels to evaluate the damage caused by low temperature operation. All analysis and experiments to date indicate that no significant damage has resulted. Future activities include a demonstration project in which the insulated pressure vessels will be installed and tested on two vehicles. A draft standard will also be generated for obtaining insulated pressure vessel certification.

  9. Plasma steam reforming of E85 for hydrogen rich gas production

    NASA Astrophysics Data System (ADS)

    Zhu, Xinli; Hoang, Trung; Lobban, Lance L.; Mallinson, Richard G.

    2011-07-01

    E85 (85 vol% ethanol and 15 vol% gasoline) is a partly renewable fuel that is increasing in supply availability. Hydrogen production from E85 for fuel cell or internal combustion engine applications is a potential method for reducing CO2 emissions. Steam reforming of E85 using a nonthermal plasma (pulse corona discharge) reactor has been exploited at low temperature (200-300 °C) without external heating, diluent gas, oxidant or catalyst in this work. Several operational parameters, including the discharge current, E85 concentration and feed flow rate, have been investigated. The results show that hydrogen rich gases (63-67% H2 and 22-29% CO, with small amounts of CO2, C2 hydrocarbons and CH4) can be produced by this method. A comparison with ethanol reforming and gasoline reforming under identical conditions has also been made and the behaviour of E85 reforming is found to be close to that of ethanol reforming with slightly higher C2 hydrocarbons yields.

  10. Nanocomposite thin films for high temperature optical gas sensing of hydrogen

    DOEpatents

    Ohodnicki, Jr., Paul R.; Brown, Thomas D.

    2013-04-02

    The disclosure relates to a plasmon resonance-based method for H.sub.2 sensing in a gas stream at temperatures greater than about 500.degree. C. utilizing a hydrogen sensing material. The hydrogen sensing material is comprised of gold nanoparticles having an average nanoparticle diameter of less than about 100 nanometers dispersed in an inert matrix having a bandgap greater than or equal to 5 eV, and an oxygen ion conductivity less than approximately 10.sup.-7 S/cm at a temperature of 700.degree. C. Exemplary inert matrix materials include SiO.sub.2, Al.sub.2O.sub.3, and Si.sub.3N.sub.4 as well as modifications to modify the effective refractive indices through combinations and/or doping of such materials. At high temperatures, blue shift of the plasmon resonance optical absorption peak indicates the presence of H.sub.2. The method disclosed offers significant advantage over active and reducible matrix materials typically utilized, such as yttria-stabilized zirconia (YSZ) or TiO.sub.2.

  11. Nitric oxide is required for hydrogen gas-induced adventitious root formation in cucumber.

    PubMed

    Zhu, Yongchao; Liao, Weibiao; Wang, Meng; Niu, Lijuan; Xu, Qingqing; Jin, Xin

    2016-05-20

    Hydrogen gas (H2) is involved in plant development and stress responses. Cucumber explants were used to study whether nitric oxide (NO) is involved in H2-induced adventitious root development. The results revealed that 50% and 100% hydrogen-rich water (HRW) apparently promoted the development of adventitious root in cucumber. While, the responses of HRW-induced adventitious rooting were blocked by a specific NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt (cPTIO), NO synthase (NOS) enzyme inhibitor N(G)-nitro-l-arginine methylester hydrochloride (l-NAME) and nitrate reductase (NR) inhibitor NaN3. HRW also increased NO content and NOS and NR activity both in a dose- and time-dependent fashion. Moreover, molecular evidence showed that HRW up-regulated NR genes expression in explants. The results indicate the importance of NOS and NR enzymes, which might be responsible for NO production in explants during H2-induced root organogenesis. Additionally, peroxidase (POD) and indoleacetic acid oxidase (IAAO) activity was significantly decreased in the explants treated with HRW, while HRW treatment significantly increased polyphenol oxidase (PPO) activity. In addition, cPTIO, l-NAME and NaN3 inhibited the actions of HRW on the activity of these enzymes. Together, NO may be involved in H2-induced adventitious rooting, and NO may be acting downstream in plant H2 signaling cascade. PMID:27010347

  12. Protein structural dynamics at the gas/water interface examined by hydrogen exchange mass spectrometry.

    PubMed

    Xiao, Yiming; Konermann, Lars

    2015-08-01

    Gas/water interfaces (such as air bubbles or foam) are detrimental to the stability of proteins, often causing aggregation. This represents a potential problem for industrial processes, for example, the production and handling of protein drugs. Proteins possess surfactant-like properties, resulting in a high affinity for gas/water interfaces. The tendency of previously buried nonpolar residues to maximize contact with the gas phase can cause significant structural distortion. Most earlier studies in this area employed spectroscopic tools that could only provide limited information. Here we use hydrogen/deuterium exchange (HDX) mass spectrometry (MS) for probing the conformational dynamics of the model protein myoglobin (Mb) in the presence of N(2) bubbles. HDX/MS relies on the principle that unfolded and/or highly dynamic regions undergo faster deuteration than tightly folded segments. In bubble-free solution Mb displays EX2 behavior, reflecting the occurrence of short-lived excursions to partially unfolded conformers. A dramatically different behavior is seen in the presence of N(2) bubbles; EX2 dynamics still take place, but in addition the protein shows EX1 behavior. The latter results from interconversion of the native state with conformers that are globally unfolded and long-lived. These unfolded species likely correspond to Mb that is adsorbed to the surface of gas bubbles. N(2) sparging also induces aggregation. To explain the observed behavior we propose a simple model, that is, "semi-unfolded" ↔ "native" ↔ "globally unfolded" → "aggregated". This model quantitatively reproduces the experimentally observed kinetics. To the best of our knowledge, the current study marks the first exploration of surface denaturation phenomena by HDX/MS. PMID:25761782

  13. Protein structural dynamics at the gas/water interface examined by hydrogen exchange mass spectrometry

    PubMed Central

    Xiao, Yiming; Konermann, Lars

    2015-01-01

    Gas/water interfaces (such as air bubbles or foam) are detrimental to the stability of proteins, often causing aggregation. This represents a potential problem for industrial processes, for example, the production and handling of protein drugs. Proteins possess surfactant-like properties, resulting in a high affinity for gas/water interfaces. The tendency of previously buried nonpolar residues to maximize contact with the gas phase can cause significant structural distortion. Most earlier studies in this area employed spectroscopic tools that could only provide limited information. Here we use hydrogen/deuterium exchange (HDX) mass spectrometry (MS) for probing the conformational dynamics of the model protein myoglobin (Mb) in the presence of N2 bubbles. HDX/MS relies on the principle that unfolded and/or highly dynamic regions undergo faster deuteration than tightly folded segments. In bubble-free solution Mb displays EX2 behavior, reflecting the occurrence of short-lived excursions to partially unfolded conformers. A dramatically different behavior is seen in the presence of N2 bubbles; EX2 dynamics still take place, but in addition the protein shows EX1 behavior. The latter results from interconversion of the native state with conformers that are globally unfolded and long-lived. These unfolded species likely correspond to Mb that is adsorbed to the surface of gas bubbles. N2 sparging also induces aggregation. To explain the observed behavior we propose a simple model, that is, “semi-unfolded” ↔ “native” ↔ “globally unfolded” → “aggregated”. This model quantitatively reproduces the experimentally observed kinetics. To the best of our knowledge, the current study marks the first exploration of surface denaturation phenomena by HDX/MS. PMID:25761782

  14. Hydrogen gas treatment prolongs replicative lifespan of bone marrow multipotential stromal cells in vitro while preserving differentiation and paracrine potentials

    SciTech Connect

    Kawasaki, Haruhisa; Guan, Jianjun; Tamama, Kenichi

    2010-07-02

    Cell therapy with bone marrow multipotential stromal cells/mesenchymal stem cells (MSCs) represents a promising approach in the field of regenerative medicine. Low frequency of MSCs in adult bone marrow necessitates ex vivo expansion of MSCs after harvest; however, such a manipulation causes cellular senescence with loss of differentiation, proliferative, and therapeutic potentials of MSCs. Hydrogen molecules have been shown to exert organ protective effects through selective reduction of hydroxyl radicals. As oxidative stress is one of the key insults promoting cell senescence in vivo as well as in vitro, we hypothesized that hydrogen molecules prevent senescent process during MSC expansion. Addition of 3% hydrogen gas enhanced preservation of colony forming early progenitor cells within MSC preparation and prolonged the in vitro replicative lifespan of MSCs without losing differentiation potentials and paracrine capabilities. Interestingly, 3% hydrogen gas treatment did not decrease hydroxyl radical, protein carbonyl, and 8-hydroxydeoxyguanosine, suggesting that scavenging hydroxyl radical might not be responsible for these effects of hydrogen gas in this study.

  15. Micro-machined thin film hydrogen gas sensor, and method of making and using the same

    NASA Technical Reports Server (NTRS)

    DiMeo, Jr., Frank (Inventor); Bhandari, Gautam (Inventor)

    2001-01-01

    A hydrogen sensor including a thin film sensor element formed, e.g., by metalorganic chemical vapor deposition (MOCVD) or physical vapor deposition (PVD), on a microhotplate structure. The thin film sensor element includes a film of a hydrogen-interactive metal film that reversibly interacts with hydrogen to provide a correspondingly altered response characteristic, such as optical transmissivity, electrical conductance, electrical resistance, electrical capacitance, magnetoresistance, photoconductivity, etc., relative to the response characteristic of the film in the absence of hydrogen. The hydrogen-interactive metal film may be overcoated with a thin film hydrogen-permeable barrier layer to protect the hydrogen-interactive film from deleterious interaction with non-hydrogen species. The hydrogen sensor of the invention may be usefully employed for the detection of hydrogen in an environment susceptible to the incursion or generation of hydrogen and may be conveniently configured as a hand-held apparatus.

  16. Radcalc for windows benchmark study: A comparison of software results with Rocky Flats hydrogen gas generation data

    SciTech Connect

    MCFADDEN, J.G.

    1999-07-19

    Radcalc for Windows Version 2.01 is a user-friendly software program developed by Waste Management Federal Services, Inc., Northwest Operations for the U.S. Department of Energy (McFadden et al. 1998). It is used for transportation and packaging applications in the shipment of radioactive waste materials. Among its applications are the classification of waste per the US. Department of Transportation regulations, the calculation of decay heat and daughter products, and the calculation of the radiolytic production of hydrogen gas. The Radcalc program has been extensively tested and validated (Green et al. 1995, McFadden et al. 1998) by comparison of each Radcalc algorithm to hand calculations. An opportunity to benchmark Radcalc hydrogen gas generation calculations to experimental data arose when the Rocky Flats Environmental Technology Site (RFETS) Residue Stabilization Program collected hydrogen gas generation data to determine compliance with requirements for shipment of waste in the TRUPACT-II (Schierloh 1998). The residue/waste drums tested at RFETS contain contaminated, solid, inorganic materials in polyethylene bags. The contamination is predominantly due to plutonium and americium isotopes. The information provided by Schierloh (1 998) of RFETS includes decay heat, hydrogen gas generation rates, calculated G{sub eff} values, and waste material type, making the experimental data ideal for benchmarking Radcalc. The following sections discuss the RFETS data and the Radcalc cases modeled with the data. Results are tabulated and also provided graphically.

  17. 40 CFR 60.5408 - What is an optional procedure for measuring hydrogen sulfide in acid gas-Tutwiler Procedure?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... of titrating hydrogen sulfide in a gas sample directly with a standard solution of iodine. (b... leveling bottle. (c) Reagents. (1) Iodine stock solution, 0.1N. Weight 12.7 g iodine, and 20 to 25 g cp potassium iodide for each liter of solution. Dissolve KI in as little water as necessary; dissolve iodine...

  18. 40 CFR 60.5408 - What is an optional procedure for measuring hydrogen sulfide in acid gas-Tutwiler Procedure?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... of titrating hydrogen sulfide in a gas sample directly with a standard solution of iodine. (b... leveling bottle. (c) Reagents. (1) Iodine stock solution, 0.1N. Weight 12.7 g iodine, and 20 to 25 g cp potassium iodide for each liter of solution. Dissolve KI in as little water as necessary; dissolve iodine...

  19. Inactivation of duck hepatitis B virus by a hydrogen peroxide gas plasma sterilization system: laboratory and 'in use' testing.

    PubMed

    Vickery, K; Deva, A K; Zou, J; Kumaradeva, P; Bissett, L; Cossart, Y E

    1999-04-01

    Human hepatitis B virus (HBV) is an important cause of nosocomial infections and can be transmitted by contaminated instruments. However, tests of the efficacy of sterilization of materials and equipment contaminated by HBV are difficult to perform because the virus cannot be cultured in the laboratory. In this study, we aimed to evaluate the capability of a low temperature, hydrogen peroxide gas plasma sterilizer (Sterrad, Advanced Sterilization Products, Irvine California,) to inactivate duck hepatitis B virus (DHBV). In laboratory efficacy studies using DHBV dried on to glass filter carriers and exposed to one-half of the hydrogen peroxide gas plasma sterilization process, there was a 10(7) or greater decrease in the viral titer, with no infectivity detected on the carriers after treatment. In-use studies were performed using a laparoscope that was experimentally contaminated with DHBV to mimic the possible transmission of infection between successive patients. Following exposure to the hydrogen peroxide gas plasma sterilization process no transmission of DHBV infection from the laparoscope occurred despite obvious visual soiling with blood (N = 8) while the transmission rate for the unprocessed laparoscope (positive control) was 100% (26/26), and that for instruments after a water wash was 63% (7/11). In conclusion the hydrogen gas plasma sterilization process completely inactivates DHBV a representative of the hepadna group of viruses.

  20. Gas phase recovery of hydrogen sulfide contaminated polymer electrolyte membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Kakati, Biraj Kumar; Kucernak, Anthony R. J.

    2014-04-01

    The effect of hydrogen sulfide (H2S) on the anode of a polymer electrolyte membrane fuel cell (PEMFC) and the gas phase recovery of the contaminated PEMFC using ozone (O3) were studied. Experiments were performed on fuel cell electrodes both in an aqueous electrolyte and within an operating fuel cell. The ex-situ analyses of a fresh electrode; a H2S contaminated electrode (23 μmolH2S cm-2); and the contaminated electrode cleaned with O3 shows that all sulfide can be removed within 900 s at room temperature. Online gas analysis of the recovery process confirms the recovery time required as around 720 s. Similarly, performance studies of an H2S contaminated PEMFC shows that complete rejuvenation occurs following 600-900 s O3 treatment at room temperature. The cleaning process involves both electrochemical oxidation (facilitated by the high equilibrium potential of the O3 reduction process) and direct chemical oxidation of the contaminant. The O3 cleaning process is more efficient than the external polarization of the single cell at 1.6 V. Application of O3 at room temperature limits the amount of carbon corrosion. Room temperature O3 treatment of poisoned fuel cell stacks may offer an efficient and quick remediation method to recover otherwise inoperable systems.

  1. Method and apparatus for converting hydrocarbon fuel into hydrogen gas and carbon dioxide

    DOEpatents

    Clawson, Lawrence G.; Mitchell, William L.; Bentley, Jeffrey M.; Thijssen, Johannes H.J.

    2000-01-01

    An apparatus and a method are disclosed for converting hydrocarbon fuel or an alcohol into hydrogen gas and carbon dioxide. The apparatus includes a first vessel having a partial oxidation reaction zone and a separate steam reforming reaction zone that is distinct from the partial oxidation reaction zone. The first vessel has a first vessel inlet at the partial oxidation reaction zone and a first vessel outlet at the steam reforming zone. The reformer also includes a helical tube extending about the first vessel. The helical tube has a first end connected to an oxygen-containing source and a second end connected to the first vessel at the partial oxidation reaction zone. Oxygen gas from an oxygen-containing source can be directed through the helical tube to the first vessel. A second vessel having a second vessel inlet and second vessel outlet is annularly disposed about the first vessel. The helical tube is disposed between the first vessel and the second vessel and gases from the first vessel can be directed through second vessel.

  2. Calorimetric Thermoelectric Gas Sensor for the Detection of Hydrogen, Methane and Mixed Gases

    PubMed Central

    Park, Nam-Hee; Akamatsu, Takafumi; Itoh, Toshio; Izu, Noriya; Shin, Woosuck

    2014-01-01

    A novel miniaturized calorimeter-type sensor device with a dual-catalyst structure was fabricated by integrating different catalysts on the hot (Pd/θ-Al2O3) and cold (Pt/α-Al2O3) ends of the device. The device comprises a calorimeter with a thermoelectric gas sensor (calorimetric-TGS), combining catalytic combustion and thermoelectric technologies. Its response for a model fuel gas of hydrogen and methane was investigated with various combustor catalyst compositions. The calorimetric-TGS devices detected H2, CH4, and a mixture of the two with concentrations ranging between 200 and 2000 ppm at temperatures of 100–400 °C, in terms of the calorie content of the gases. It was necessary to reduce the much higher response voltage of the TGS to H2 compared to CH4. We enhanced the H2 combustion on the cold side so that the temperature differences and response voltages to H2 were reduced. The device response to H2 combustion was reduced by 50% by controlling the Pt concentration in the Pt/α-Al2O3 catalyst on the cold side to 3 wt%. PMID:24818660

  3. Calorimetric thermoelectric gas sensor for the detection of hydrogen, methane and mixed gases.

    PubMed

    Park, Nam-Hee; Akamatsu, Takafumi; Itoh, Toshio; Izu, Noriya; Shin, Woosuck

    2014-01-01

    A novel miniaturized calorimeter-type sensor device with a dual-catalyst structure was fabricated by integrating different catalysts on the hot (Pd/θ-Al2O3) and cold (Pt/α-Al2O3) ends of the device. The device comprises a calorimeter with a thermoelectric gas sensor (calorimetric-TGS), combining catalytic combustion and thermoelectric technologies. Its response for a model fuel gas of hydrogen and methane was investigated with various combustor catalyst compositions. The calorimetric-TGS devices detected H2, CH4, and a mixture of the two with concentrations ranging between 200 and 2000 ppm at temperatures of 100-400 °C, in terms of the calorie content of the gases. It was necessary to reduce the much higher response voltage of the TGS to H2 compared to CH4. We enhanced the H2 combustion on the cold side so that the temperature differences and response voltages to H2 were reduced. The device response to H2 combustion was reduced by 50% by controlling the Pt concentration in the Pt/α-Al2O3 catalyst on the cold side to 3 wt%. PMID:24818660

  4. Enhanced physical properties of porous silicon for improved hydrogen gas sensing

    NASA Astrophysics Data System (ADS)

    Naderi, N.; Hashim, M. R.; Amran, T. S. T.

    2012-05-01

    In the current communication, porous silicon samples were prepared by pulsed photoelectrochemical etching using a hydrofluoric acid-based solution. The structural and gas-sensing properties of the samples were studied. Apart from the cycle time T and pause time Toff of the pulsed current, a novel parameter, in the shape of the current named 'delay time Td' was introduced. Our results showed that by optimization of delay time, the porosity of samples can be controlled due to the chemical preparation of silicon surface prior to electrochemical anodization. The fourier-transform infrared measurements of porous silicon (PS) layers on Si substrate showed that the typical PS surface was characterized by chemical species like Si-H and Si-O-Si terminations. The two-minute delay before applying electrical current was considered sufficient for the fabrication of higher porosity (83%), more uniform, and more stable structures. The photoluminescence (PL) peak of the optimized sample showed higher intensity than the other samples. An obvious PL blue shift also revealed a change in the crystallographic characteristics of silicon due to quantum confinement effects. Metal-semiconductor-metal diodes with Schottky contacts of nickel were fabricated on PS samples and the potential application of optimized substrates for the improved sensitivity, stability, response time and recovery time of hydrogen gas sensors was subsequently studied.

  5. Calorimetric thermoelectric gas sensor for the detection of hydrogen, methane and mixed gases.

    PubMed

    Park, Nam-Hee; Akamatsu, Takafumi; Itoh, Toshio; Izu, Noriya; Shin, Woosuck

    2014-05-09

    A novel miniaturized calorimeter-type sensor device with a dual-catalyst structure was fabricated by integrating different catalysts on the hot (Pd/θ-Al2O3) and cold (Pt/α-Al2O3) ends of the device. The device comprises a calorimeter with a thermoelectric gas sensor (calorimetric-TGS), combining catalytic combustion and thermoelectric technologies. Its response for a model fuel gas of hydrogen and methane was investigated with various combustor catalyst compositions. The calorimetric-TGS devices detected H2, CH4, and a mixture of the two with concentrations ranging between 200 and 2000 ppm at temperatures of 100-400 °C, in terms of the calorie content of the gases. It was necessary to reduce the much higher response voltage of the TGS to H2 compared to CH4. We enhanced the H2 combustion on the cold side so that the temperature differences and response voltages to H2 were reduced. The device response to H2 combustion was reduced by 50% by controlling the Pt concentration in the Pt/α-Al2O3 catalyst on the cold side to 3 wt%.

  6. Removal of hydrogen sulfide gas and landfill leachate treatment using coal bottom ash.

    PubMed

    Lin, C Y; Hesu, P H; Yang, D H

    2001-06-01

    Coal bottom ashes produced from three thermal power plants were used in column and batch experiments to investigate the adsorption capacity of the coal ash. Hydrogen sulfide and leachates collected from three sanitary landfill sites were used as adsorbate gas and solutions, respectively. Experimental results showed that coal bottom ash could remove H2S from waste gas or reduce the concentrations of various pollutants in the leachate. Each gram of bottom ash could remove up to 10.5 mg of H2S. In treating the landfill leachate, increasing ash dosage increased the removal efficiency but decreased the adsorption amount per unit mass of ash. For these tested ashes, the removal efficiencies of chemical oxygen demand (COD), NH3-N, total Kjeldhal nitrogen (TKN), P, Fe3+, Mn2+, and Zn2+ were 36.4-50, 24.2-39.4, 27.0-31.1, 82.2-92.9, 93.8-96.5, 93.7-95.4, and 80.5-82.2%, respectively; the highest adsorption capacities for those parameters were 3.5-5.6, 0.22-0.63, 0.36-0.45, 0.027-0.034, 0.050-0.053, 0.029-0.032, and 0.006 mg/g of bottom ash, respectively. The adsorption of pollutants in the leachate conformed to Freundlich's adsorption model.

  7. In situ gasification process for producing product gas enriched in carbon monoxide and hydrogen

    DOEpatents

    Capp, John P.; Bissett, Larry A.

    1978-01-01

    The present invention is directed to an in situ coal gasification process wherein the combustion zone within the underground coal bed is fed with air at increasing pressure to increase pressure and temperature in the combustion zone for forcing product gases and water naturally present in the coal bed into the coal bed surrounding the combustion zone. No outflow of combustion products occurs during the build-up of pressure and temperature in the combustion zone. After the coal bed reaches a temperature of about 2000.degree. F and a pressure in the range of about 100-200 psi above pore pressure the airflow is terminated and the outflow of the combustion products from the combustion zone is initiated. The CO.sub.2 containing gaseous products and the water bleed back into the combustion zone to react endothermically with the hot carbon of the combustion zone to produce a burnable gas with a relatively high hydrogen and carbon monoxide content. About 11 to 29 percent of the gas recovered from the combustion zone is carbon monoxide which is considerably better than the 4 to 10 percent carbon monoxide obtained by employing previously known coal gasification techniques.

  8. Hydrogen generation in a microhollow cathode discharge in high-pressure ammonia-argon gas mixtures

    NASA Astrophysics Data System (ADS)

    Qiu, H.; Martus, K.; Lee, W. Y.; Becker, K.

    2004-04-01

    We explored the feasibility of using a single flow-through microhollow cathode discharge (MHCD) as a non-thermal plasma source for hydrogen (H2) production for portable fuel cell applications. The MHCD device consisted of two thin metal electrodes separated by a mica spacer with a single-hole, roughly 100 [mu]m in diameter, through all three layers. The efficiency of the MHCD reactor for H2 generation from NH3 was analyzed by monitoring the products formed in the discharge in a mass spectrometer. Using a gas mixture of up to 10% NH3 in Ar at pressures up to one atmosphere, the MHCD reactor achieved a maximum ammonia conversion of slightly more than 20%. The overall power efficiency of the MHCD reactor reached a peak value of about 11%. The dependence of NH3 conversion and power efficiency on the residence time of the gas in the MHCD plasma was studied. Experiments using pulsed excitation of the MHCD plasma indicated that pulsing can increase the power efficiency. Design and operating criteria are proposed for a microplasma-based H2 generator that can achieve a power efficiency above the break-even point, i.e., a microplasma reactor that requires less electrical power to generate and maintain the plasma than the power that can be obtained from the conversion of the H2 generated in the microplasma reactor.

  9. Performance, Efficiency, and Emissions Characterization of Reciprocating Internal Combustion Engines Fueled with Hydrogen/Natural Gas Blends

    SciTech Connect

    Kirby S. Chapman; Amar Patil

    2007-06-30

    Hydrogen is an attractive fuel source not only because it is abundant and renewable but also because it produces almost zero regulated emissions. Internal combustion engines fueled by compressed natural gas (CNG) are operated throughout a variety of industries in a number of mobile and stationary applications. While CNG engines offer many advantages over conventional gasoline and diesel combustion engines, CNG engine performance can be substantially improved in the lean operating region. Lean operation has a number of benefits, the most notable of which is reduced emissions. However, the extremely low flame propagation velocities of CNG greatly restrict the lean operating limits of CNG engines. Hydrogen, however, has a high flame speed and a wide operating limit that extends into the lean region. The addition of hydrogen to a CNG engine makes it a viable and economical method to significantly extend the lean operating limit and thereby improve performance and reduce emissions. Drawbacks of hydrogen as a fuel source, however, include lower power density due to a lower heating value per unit volume as compared to CNG, and susceptibility to pre-ignition and engine knock due to wide flammability limits and low minimum ignition energy. Combining hydrogen with CNG, however, overcomes the drawbacks inherent in each fuel type. Objectives of the current study were to evaluate the feasibility of using blends of hydrogen and natural gas as a fuel for conventional natural gas engines. The experiment and data analysis included evaluation of engine performance, efficiency, and emissions along with detailed in-cylinder measurements of key physical parameters. This provided a detailed knowledge base of the impact of using hydrogen/natural gas blends. A four-stroke, 4.2 L, V-6 naturally aspirated natural gas engine coupled to an eddy current dynamometer was used to measure the impact of hydrogen/natural gas blends on performance, thermodynamic efficiency and exhaust gas emissions

  10. CIRCUMBINARY GAS ACCRETION ONTO A CENTRAL BINARY: INFRARED MOLECULAR HYDROGEN EMISSION FROM GG Tau A

    SciTech Connect

    Beck, Tracy L.; Lubow, S. H.; Bary, Jeffrey S.; Dutrey, Anne; Guilloteau, Stephane; Pietu, Vincent; Simon, M. E-mail: lubow@stsci.edu E-mail: Anne.Dutrey@obs.u-bordeaux1.fr E-mail: pietu@iram.fr

    2012-07-20

    We present high spatial resolution maps of ro-vibrational molecular hydrogen emission from the environment of the GG Tau A binary component in the GG Tau quadruple system. The H{sub 2} v = 1-0 S(1) emission is spatially resolved and encompasses the inner binary, with emission detected at locations that should be dynamically cleared on several hundred year timescales. Extensions of H{sub 2} gas emission are seen to {approx}100 AU distances from the central stars. The v = 2-1 S(1) emission at 2.24 {mu}m is also detected at {approx}30 AU from the central stars, with a line ratio of 0.05 {+-} 0.01 with respect to the v = 1-0 S(1) emission. Assuming gas in LTE, this ratio corresponds to an emission environment at {approx}1700 K. We estimate that this temperature is too high for quiescent gas heated by X-ray or UV emission from the central stars. Surprisingly, we find that the brightest region of H{sub 2} emission arises from a spatial location that is exactly coincident with a recently revealed dust 'streamer' which seems to be transferring material from the outer circumbinary ring around GG Tau A into the inner region. As a result, we identify a new excitation mechanism for ro-vibrational H{sub 2} stimulation in the environment of young stars. The H{sub 2} in the GG Tau A system appears to be stimulated by mass accretion infall as material in the circumbinary ring accretes onto the system to replenish the inner circumstellar disks. We postulate that H{sub 2} stimulated by accretion infall could be present in other systems, particularly binaries and 'transition disk' systems which have dust-cleared gaps in their circumstellar environments.

  11. The Hy-C process (thermal decomposition of natural gas): Potentially the lowest cost source of hydrogen with the least CO{sub 2} emission

    SciTech Connect

    Steinberg, M.

    1994-12-01

    The abundance of natural gas as a natural resource and its high hydrogen content make it a prime candidate for a low cost supply of hydrogen. The thermal decomposition of natural gas by methane pyrolysis produces carbon and hydrogen. The process energy required to produce one mol of hydrogen is only 5.3% of the higher heating value of methane. The thermal efficiency for hydrogen production as a fuel without the use of carbon as a fuel, can be as high as 60%. Conventional steam reforming of methane requires 8.9% process energy per mole of hydrogen even though 4 moles of hydrogen can be produced per mole of methane, compared to 2 moles by methane pyrolysis. When considering greenhouse global gas warming, methane pyrolysis produces the least amount of CO{sub 2} emissions per unit of hydrogen and can be totally eliminated when the carbon produced is either sequestered or sold as a materials commodity, and hydrogen is used to fuel the process. Conventional steam reforming of natural gas and CO shifting produces large amounts of CO{sub 2} emissions. The energy requirement for non-fossil, solar, nuclear, and hydropower production of hydrogen, mainly through electrolysis, is much greater than that from natural gas. From the resource available energy and environmental points of view, production of hydrogen by methane pyrolysis is most attractive. The by-product carbon black, when credited as a saleable material, makes hydrogen by thermal decomposition of natural gas (the Hy-C process) potentially the lowest cost source of large amounts of hydrogen.

  12. Practical sublimation source for large-scale chromium gettering in fusion devices

    SciTech Connect

    Simpkins, J.E.; Emerson, L.C.; Mioduszewski, P.K.

    1983-01-01

    This paper describes the technique of chromium gettering with a large-scale sublimation source which resembles in its design the VARIAN Ti-Ball. It consists of a hollow chromium sphere with a diameter of approximately 3 cm and an incandescent filament for radiation heating from inside the ball. While the fabrication of the source is described in a companion paper, we discuss here the gettering technique. The experimental arrangement consists of an UHV system instrumented for total- and partial-pressure measurements, a film-thickness monitor, thermocouples, an optical pyrometer, and appropriate instrumentation to measure the heating power. The results show the temperature and corresponding sublimation rate of the Cr-Ball as function of input power. In addition, an example of the total pumping speed of a gettered surface is shown.

  13. Gettering of transition metals by cavities in silicon formed by helium ion implantation

    SciTech Connect

    Petersen, G.A.; Myers, S.M.; Follstaedt, D.M.

    1996-09-01

    We have recently completed studies which quantitatively characterize the ability of nanometer-size cavities formed by He ion implantation to getter detrimental metal impurities in Si. Cavity microstructures formed in Si by ion implantation of He and subsequent annealing have been found to capture metal impurities by two mechanisms: (1) chemisorption on internal walls at low concentrations and (2) silicide precipitation at concentrations exceeding the solid solubility. Experiments utilizing ion-beam analysis, cross-sectional transmission electron microscopy, and secondary ion mass spectrometry were performed to quantitatively characterize the gettering effects and to determine the free energies associated with the chemisorbed metal atoms as a function of temperature. Mathematical models utilizing these results have been developed to predict gettering behavior.

  14. Neon as a Buffer Gas for a Mercury-Ion Clock

    NASA Technical Reports Server (NTRS)

    Prestage, John; Chung, Sang

    2008-01-01

    A developmental miniature mercury-ion clock has stability comparable to that of a hydrogen-maser clock. The ion-handling components are housed in a sealed vacuum tube, wherein a getter pump is used to maintain the partial vacuum, and the evacuated tube is backfilled with mercury vapor in a buffer gas. Neon was determined to be the best choice for the buffer gas: The pressure-induced frequency pulling by neon was found to be only about two-fifths of that of helium. Furthermore, because neon diffuses through solids much more slowly than does helium, the operational lifetime of a tube backfilled with neon could be considerably longer than that of a tube backfilled with helium.

  15. Hydrogen Selective Inorganic membranes for Gas Separations under High Pressure Intermediate Temperature Hydrocarbonic Envrionment

    SciTech Connect

    Rich Ciora; Paul KT Liu

    2012-06-27

    In this project, we have successfully developed a full scale commercially ready carbon molecular sieve (CMS) based membrane for applications in H{sub 2} recovery from refinery waste and other aggressive gas streams. Field tests at a refinery pilot plant and a coal gasification facility have successfully demonstrated its ability to recovery hydrogen from hydrotreating and raw syngas respectively. High purity H{sub 2} and excellent stability of the membrane permeance and selectivity were obtained in testing conducted over >500 hours at each site. The results from these field tests as well as laboratory testing conclude that the membranes can be operated at high pressures (up to 1,000 psig) and temperatures (up to 300 C) in presence of aggressive contaminants, such as sulfur and nitrogen containing species (H{sub 2}S, CO{sub 2}, NH{sub 3}, etc), condensable hydrocarbons, tar-like species, heavy metals, etc. with no observable effect on membrane performance. By comparison, similar operating conditions and/or environments would rapidly destroy competing membranes, such as polymeric, palladium, zeolitic, etc. Significant cost savings can be achieved through recovering H{sub 2} from refinery waste gas using this newly developed CMS membrane. Annual savings of $2 to 4MM/year (per 20,000 scfd of waste gas) can be realized by recovering the H{sub 2} for reuse (versus fuel). Projecting these values over the entire US market, potential H{sub 2} savings from refinery waste gases on the order of 750 to 1,000MM scfd and $750 to $1,000MM per year are possible. In addition to the cost savings, potential energy savings are projected to be ca. 150 to 220 tBTU/yr and CO{sub 2} gas emission reductions are projected to be ca. 5,000 to 6,500MMtons/year. The full scale membrane bundle developed as part of this project, i.e., 85 x 30 inch ceramic membrane tubes packaged into a full ceramic potting, is an important accomplishment. No comparable commercial scale product exists in the

  16. [Gas chromatography with a Pulsed discharge helium ionization detector for measurement of molecular hydrogen(H2) in the atmosphere].

    PubMed

    Luan, Tian; Fang, Shuang-xi; Zhou, Ling-xi; Wang, Hong-yang; Zhang, Gen

    2015-01-01

    A high precision GC system with a pulsed discharge helium ionization detector was set up based on the commercial Agilent 7890A gas chromatography. The gas is identified by retention time and the concentration is calculated through the peak height. Detection limit of the system is about 1 x 10(-9) (mole fraction, the same as below). The standard deviation of 140 continuous injections with a standard cylinder( concentration is roughly 600 x 10(-9)) is better than 0.3 x 10(-9). Between 409.30 x 10(-9) and 867.74 x 10(-9) molecular hydrogen mole fractions and peak height have good linear response. By using two standards to quantify the air sample, the precision meets the background molecular hydrogen compatibility goal within the World Meteorological Organization/Global Atmosphere Watch (WMO/GAW) program. Atmospheric molecular hydrogen concentration at Guangzhou urban area was preliminarily measured by this method from January to November 2013. The results show that the atmospheric molecular hydrogen mole fraction varies from 450 x 10(-9) to 700 x 10(-9) during the observation period, with the lowest value at 14:00 (Beijing time, the same as below) and the peak value at 20:00. The seasonal variation of atmospheric hydrogen at Guangzhou area was similar with that of the same latitude stations in northern hemisphere.

  17. Performance of a hydrogen/deuterium polarized gas target in a storage ring

    NASA Astrophysics Data System (ADS)

    van Buuren, L. D.; Szczerba, D.; van den Brand, J. F. J.; Bulten, H. J.; Ferro-Luzzi, M.; Klous, S.; Kolster, H.; Lang, J.; Mul, F. A.; Poolman, H. R.; Simani, M. C.

    2001-12-01

    The performance of a high-density polarized hydrogen/deuterium gas target internal to a medium-energy electron storage ring is presented. Compared to our previous electron scattering experiments with tensor-polarized deuterium at NIKHEF (Zhou et al., Nucl. Instr. and Meth. A 378 (1996) 40; Ferro-Luzzi et al., Phys. Rev. Lett. 77 (1996) 2630; Van den Brand et al., Phys. Rev. Lett. 78 (1997) 1235; Bouwhuis et al., Phys. Rev. Lett. 82 (1999) 687; Zhou et al., Phys. Rev. Lett. 82 (1999) 687) the target figure of merit, ( polarization) 2× luminosity, was improved by more than an order of magnitude. The target density was increased by upgrading the flux of nuclear-polarized atoms injected into the storage cell and by using a longer (60 cm) and colder (˜70 K) storage cell. A maximal target thickness of 1.2 (1.1)±0.1×10 14 nuclei/ cm2 was achieved with deuterium (hydrogen). With typical beam currents of 110 mA, this corresponds to a luminosity of about 8.4 (7.8)±0.8×10 31e- nuclei cm -2 s-1. By reducing the molecular background and using a stronger target guide field, a higher polarization was achieved. The target was used in combination with a 720 MeV polarized electron beam stored in the AmPS ring (NIKHEF) to measure spin observables in electron-proton and electron-deuteron scattering. Scattered electrons were detected in a large acceptance magnetic spectrometer. Ejected hadrons were detected in a single time-of-flight scintillator array. The product of beam and target vector polarization, PePt, was determined from the known spin-correlation parameters of e' p quasi-elastic (or elastic) scattering. With the deuterium (hydrogen) target, values up to PePt=0.49±0.03 (0.32±0.03) were obtained with an electron beam polarization of Pe=0.62±0.04 (0.56±0.03) as measured with a Compton backscattering polarimeter (Passchier et al., Nucl. Instr. and Meth. A 414 (1998) 4988). From this, we deduce a cell-averaged target polarization of Pt=0.78±0.07 (0.58±0.07), including

  18. Hydrogen production from food wastes and gas post-treatment by CO{sub 2} adsorption

    SciTech Connect

    Redondas, V.; Gomez, X.; Garcia, S.; Pevida, C.; Rubiera, F.; Moran, A.; Pis, J.J.

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer The dark fermentation process of food wastes was studied over an extended period. Black-Right-Pointing-Pointer Decreasing the HRT of the process negatively affected the specific gas production. Black-Right-Pointing-Pointer Adsorption of CO{sub 2} was successfully attained using a biomass type activated carbon. Black-Right-Pointing-Pointer H{sub 2} concentration in the range of 85-95% was obtained for the treated gas-stream. - Abstract: The production of H{sub 2} by biological means, although still far from being a commercially viable proposition, offers great promise for the future. Purification of the biogas obtained may lead to the production of highly concentrated H{sub 2} streams appropriate for industrial application. This research work evaluates the dark fermentation of food wastes and assesses the possibility of adsorbing CO{sub 2} from the gas stream by means of a low cost biomass-based adsorbent. The reactor used was a completely stirred tank reactor run at different hydraulic retention times (HRTs) while the concentration of solids of the feeding stream was kept constant. The results obtained demonstrate that the H{sub 2} yields from the fermentation of food wastes were affected by modifications in the hydraulic retention time (HRT) due to incomplete hydrolysis. The decrease in the duration of fermentation had a negative effect on the conversion of the substrate into soluble products. This resulted in a lower amount of soluble substrate being available for metabolisation by H{sub 2} producing microflora leading to a reduction in specific H{sub 2} production. Adsorption of CO{sub 2} from a gas stream generated from the dark fermentation process was successfully carried out. The data obtained demonstrate that the column filled with biomass-derived activated carbon resulted in a high degree of hydrogen purification. Co-adsorption of H{sub 2}S onto the activated carbon also took place, there being no evidence of H

  19. PALLADIUM/COPPER ALLOY COMPOSITE MEMBRANES FOR HIGH TEMPERATURE HYDROGEN SEPARATION FROM COAL-DERIVED GAS STREAMS

    SciTech Connect

    J. Douglas Way

    2003-01-01

    For hydrogen from coal gasification to be used economically, processing approaches that produce a high purity gas must be developed. Palladium and its alloys, nickel, platinum and the metals in Groups 3 to 5 of the Periodic Table are all permeable to hydrogen. Hydrogen permeable metal membranes made of palladium and its alloys are the most widely studied due to their high hydrogen permeability, chemical compatibility with many hydrocarbon containing gas streams, and infinite hydrogen selectivity. Our Pd composite membranes have demonstrated stable operation at 450 C for over 70 days. Coal derived synthesis gas will contain up to 15000 ppm H{sub 2}S as well as CO, CO{sub 2}, N{sub 2} and other gases. Highly selectivity membranes are necessary to reduce the H{sub 2}S concentration to acceptable levels for solid oxide and other fuel cell systems. Pure Pd-membranes are poisoned by sulfur, and suffer from mechanical problems caused by thermal cycling and hydrogen embrittlement. Recent advances have shown that Pd-Cu composite membranes are not susceptible to the mechanical, embrittlement, and poisoning problems that have prevented widespread industrial use of Pd for high temperature H{sub 2} separation. These membranes consist of a thin ({le} 5 {micro}m) film of metal deposited on the inner surface of a porous metal or ceramic tube. With support from this DOE Grant, we have fabricated thin, high flux Pd-Cu alloy composite membranes using a sequential electroless plating approach. Thin, Pd{sub 60}Cu{sub 40} films exhibit a hydrogen flux more than ten times larger than commercial polymer membranes for H{sub 2} separation, resist poisoning by H{sub 2}S and other sulfur compounds typical of coal gas, and exceed the DOE Fossil Energy target hydrogen flux of 80 ml/cm{sup 2} {center_dot} min = 0.6 mol/m{sup 2} {center_dot} s for a feed pressure of 40 psig. Similar Pd-membranes have been operated at temperatures as high as 750 C. We have developed practical electroless plating

  20. Hydrogen pellet acceleration with a two-stage system consisting of a gas gun and a fuseless electromagnetic railgun

    SciTech Connect

    Honig, J.; Kim, K.; Wedge, S.W.

    1986-05-01

    Hydrogen pellets are successfully accelerated for the first time using a two-stage system consisting of a pneumatic gun and an electromagnetic railgun. The pneumatic gun preaccelerator forms cylindrical hydrogen ice pellets (1.6-mm diam x 2.15-mm long) and accelerates them with high-pressure helium gas to velocities in excess of 500 m/s. The booster accelerator, which is a fuseless, circular-bore electromagnetic railgun, derives its propulsive force from a plasma arc armature. The plasma arc armature is formed by electrically breaking down the propellant gas which follows the pellet from the gas gun into the railgun. The diagnostics are for the monitoring of the main capacitor bank and rail currents, for the pellet detection and velocity measurements at the breech and muzzle ends of the railgun, for the recording of the plasma-arc-armature movement inside the railgun bore, and for the photographing of the hydrogen pellet exiting the railgun. Using the system, which is a 60-cm long proof-of-principle machine for refueling magnetic fusion devices, hyrogen pellet velocities exceeding 1 km/s have been achieved for pellets exiting the gas gun at velocities of approx.500 m/s.

  1. Detection of exhaled hydrogen sulphide gas in healthy human volunteers during intravenous administration of sodium sulphide

    PubMed Central

    Toombs, Christopher F; Insko, Michael A; Wintner, Edward A; Deckwerth, Thomas L; Usansky, Helen; Jamil, Khurram; Goldstein, Brahm; Cooreman, Michael; Szabo, Csaba

    2010-01-01

    INTRODUCTION Hydrogen sulphide (H2S) is an endogenous gaseous signaling molecule and potential therapeutic agent. Emerging studies indicate its therapeutic potential in a variety of cardiovascular diseases and in critical illness. Augmentation of endogenous sulphide concentrations by intravenous administration of sodium sulphide can be used for the delivery of H2S to the tissues. In the current study, we have measured H2S concentrations in the exhaled breath of healthy human volunteers subjected to increasing doses sodium sulphide in a human phase I safety and tolerability study. METHODS We have measured reactive sulphide in the blood via ex vivo derivatization of sulphide with monobromobimane to form sulphide-dibimane and blood concentrations of thiosulfate (major oxidative metabolite of sulphide) via ion chromatography. We have measured exhaled H2S concentrations using a custom-made device based on a sulphide gas detector (Interscan). RESULTS Administration of IK-1001, a parenteral formulation of Na2S (0.005–0.20 mg kg−1, i.v., infused over 1 min) induced an elevation of blood sulphide and thiosulfate concentrations over baseline, which was observed within the first 1–5 min following administration of IK-1001 at 0.10 mg kg−1 dose and higher. In all subjects, basal exhaled H2S was observed to be higher than the ambient concentration of H2S gas in room air, indicative of on-going endogenous H2S production in human subjects. Upon intravenous administration of Na2S, a rapid elevation of exhaled H2S concentrations was observed. The amount of exhaled H2S rapidly decreased after discontinuation of the infusion of Na2S. CONCLUSION Exhaled H2S represents a detectable route of elimination after parenteral administration of Na2S. PMID:20565454

  2. Hydrogen production from food wastes and gas post-treatment by CO2 adsorption.

    PubMed

    Redondas, V; Gómez, X; García, S; Pevida, C; Rubiera, F; Morán, A; Pis, J J

    2012-01-01

    The production of H(2) by biological means, although still far from being a commercially viable proposition, offers great promise for the future. Purification of the biogas obtained may lead to the production of highly concentrated H(2) streams appropriate for industrial application. This research work evaluates the dark fermentation of food wastes and assesses the possibility of adsorbing CO(2) from the gas stream by means of a low cost biomass-based adsorbent. The reactor used was a completely stirred tank reactor run at different hydraulic retention times (HRTs) while the concentration of solids of the feeding stream was kept constant. The results obtained demonstrate that the H(2) yields from the fermentation of food wastes were affected by modifications in the hydraulic retention time (HRT) due to incomplete hydrolysis. The decrease in the duration of fermentation had a negative effect on the conversion of the substrate into soluble products. This resulted in a lower amount of soluble substrate being available for metabolisation by H(2) producing microflora leading to a reduction in specific H(2) production. Adsorption of CO(2) from a gas stream generated from the dark fermentation process was successfully carried out. The data obtained demonstrate that the column filled with biomass-derived activated carbon resulted in a high degree of hydrogen purification. Co-adsorption of H(2)S onto the activated carbon also took place, there being no evidence of H(2)S present in the bio-H(2) exiting the column. Nevertheless, the concentration of H(2)S was very low, and this co-adsorption did not affect the CO(2) capture capacity of the activated carbon.

  3. Thin liquid/gas diffusion layers for high-efficiency hydrogen production from water splitting

    DOE PAGES

    Mo, Jingke; Retterer, Scott T.; Cullen, David A.; Toops, Todd J.; Green, Jr, Johney Boyd; Zhang, Feng-Yuan

    2016-06-13

    Liquid/gas diffusion layers (LGDLs) play a crucial role in electrochemical energy technology and hydrogen production, and are expected to simultaneously transport electrons, heat, and reactants/products with minimum voltage, current, thermal, interfacial, and fluidic losses. In addition, carbon materials, which are typically used in proton exchange membrane fuel cells (PEMFCs), are unsuitable for PEM electrolyzer cells (PEMECs). In this study, a novel titanium thin LGDL with well-tunable pore morphologies was developed by employing nano-manufacturing and was applied in a standard PEMEC. The LGDL tests show significant performance improvements. The operating voltages required at a current density of 2.0 A/cm2 were asmore » low as 1.69 V, and its efficiency reached a report high of up to 88%. The new thin and flat LGDL with well-tunable straight pores has been demonstrated to remarkably reduce the ohmic, interfacial and transport losses. In addition, well-tunable features, including pore size, pore shape, pore distribution, and thus porosity and permeability, will be very valuable for developing PEMEC models and for validation of its simulations with optimal and repeatable performance. The LGDL thickness reduction from greater than 350 μm of conventional LGDLs to 25 μm will greatly decrease the weight and volume of PEMEC stacks, and represents a new direction for future developments of low-cost PEMECs with high performance.« less

  4. CFD study on Taconis thermoacoustic oscillation with cryogenic hydrogen as working gas

    NASA Astrophysics Data System (ADS)

    Sun, Daming; Wang, Kai; Guo, Yinan; Zhang, Jie; Xu, Ya; Zou, Jiang; Zhang, Xiaobin

    2016-04-01

    Taconis oscillation is a kind of typical self-excited thermoacoustic oscillation, the study of which is of great significance to reveal the thermoacoustic conversion effect and find ways to suppress self-excited oscillation in cryogenic systems. Based on computational fluid dynamics (CFD) method, the onset process of Taconis oscillation with low temperature hydrogen at atmospheric pressure as working gas is first simulated. It is shown that a standing-wave acoustic field operating at 91 Hz starts spontaneously and finally develops to a saturation state in the Taconis tube with length and inner diameter of 1 m and 0.01 m respectively. Parametric variations in both axial and radial directions of thermoacoustic field are then studied in detail. By combining the computational results with Rott's theory, the spatial distributions of viscous dissipation, thermal relaxation dissipation, and source/sink terms of Taconis thermoacoustic oscillation are obtained quantitatively. The dissipation and source terms are found to be mainly brought forth by the traveling-wave and standing-wave components of the acoustic field, respectively.

  5. Effect of hydrogen gas on the survival rate of mice following global cerebral ischemia.

    PubMed

    Nagatani, Kimihiro; Wada, Kojiro; Takeuchi, Satoru; Kobayashi, Hiroaki; Uozumi, Yoichi; Otani, Naoki; Fujita, Masanori; Tachibana, Shoichi; Nawashiro, Hiroshi

    2012-06-01

    Global cerebral ischemia and reperfusion (I/R) often result in high mortality. Free radicals have been reported to play an important role in global cerebral I/R, and therefore, reduction of these might improve the outcome. Here, we investigated the effect of hydrogen gas (H2) (a strong free radical scavenger) on the survival rate of mice following global cerebral I/R. We further examined the histopathological outcome and also the brain water content (as a possible determinant of mortality). Male C57BL/6J mice were subjected to global cerebral I/R by means of 45-min bilateral common carotid artery occlusion (BCCAO). A total of 160 mice were divided into three groups: sham surgery (sham group), BCCAO without H2 (BCCAO group), and BCCAO treated with 1.3% H2 (BCCAO + H2 group). We observed that H2 treatment significantly (P = 0.0232) improved the 7-day survival rate of mice, from 8.3% (BCCAO group, n = 12) to 50% (BCCAO + H2 group, n = 10). Histopathological analysis revealed that H2 treatment significantly attenuated neuronal injury and autophagy in the hippocampal cornu ammonis 1 sector and also brain edema, after 24 h of reperfusion. The beneficial effects of H2 treatment on brain injury were associated with significantly lower levels of oxidative stress markers (8-hydroxy-2'-deoxyguanosine and malondialdehyde) in the brain tissue. Thus, we believe that H2 may be an effective treatment for global cerebral I/R.

  6. Sunlight-promoted photocatalytic hydrogen gas evolution from water-suspended cellulose: a systematic study.

    PubMed

    Speltini, Andrea; Sturini, Michela; Dondi, Daniele; Annovazzi, Enrico; Maraschi, Federica; Caratto, Valentina; Profumo, Antonella; Buttafava, Armando

    2014-10-01

    This work presents a systematic study of cellulose (CLS) as a sacrificial biomass for photocatalytic H2 evolution from water. The idea is indeed to couple a largely available and not expensive biomass, and water, with a renewable energy like solar radiation. An aqueous CLS suspension irradiated either at 366 nm (UV-A) or under sunlight in the presence of Pt/TiO2 behaves as a H2 evolving system. The effects of irradiation time, catalyst and CLS concentrations, pH and water salinity are studied. Addition of CLS to the sample significantly improved H2 evolution from water splitting, with yields up to ten fold higher than those observed in neat water. The mechanism of the photocatalytic process relies on the TiO2-mediated CLS hydrolysis, under irradiation. The polysaccharide depolymerisation generates water-soluble species and intermediates, among them 5-hydroxymethylfurfural (HMF) was identified. These intermediates are readily oxidized following the glucose photoreforming, thus enhancing water hydrogen ion reduction to give gas-phase H2. The formation of "colored" by-products from HMF self-polymerization involves a sort of "in situ dye sensitization" that allows an effective photoreaction even under solar light. The procedure is evaluated and successfully extended on cellulosic biomasses, i.e. rice husk and alfalfa (Medicago sativa) stems, not previously investigated for this application.

  7. Photoluminescence and hydrogen gas-sensing properties of titanium dioxide nanostructures synthesized by hydrothermal treatments.

    PubMed

    Sikhwivhilu, Lucky M; Mpelane, Siyasanga; Mwakikunga, Bonex W; Ray, Suprakas Sinha

    2012-03-01

    Titanium dioxide (TiO(2)) nanostructures were synthesized by microwave-assisted and conventionally heated hydrothermal treatment of TiO(2) powder. The tubular structures were converted to a rodlike shape by sintering the samples at various temperatures in air for 3 h. This was accompanied by phase transformation largely influenced by the method of synthesis and the mode of heating. The X-ray diffraction results are in agreement with the structural transformation indicating the gradual changes in the phase and crystallinity of the as prepared samples. The tubular structure is found to collapse at high temperature. UV-vis-IR spectroscopic results suggest that nanorods tend to absorb photons of higher energy (λ = 280 nm) than nanotubes (λ = 300 nm) but emit photons with lower energy than nanotubes. It was found that the nanotubes have a sharper photoluminance emission line at 340 nm that is absent in the nanorods. We also found that nanotubes have higher efficiency, lower threshold sensing temperature, longer response time, and shorter recovery time for hydrogen gas sensing than nanorods. PMID:22352872

  8. Hydrogen-rich gas production via CaO sorption-enhanced steam gasification of rice husk: a modelling study.

    PubMed

    Beheshti, Sayyed Mohsen; Ghassemi, Hojat; Shahsavan-Markadeh, Rasoul; Fremaux, Sylvain

    2015-01-01

    Gasification is a thermochemical process in which solid or liquid fuels are transformed into synthesis gas through partial oxidation. In this paper, a kinetic model of rice husk gasification has been developed, which is interesting for the applications of the syngas produced. It is a zero-dimensional, steady-state model based on global reaction kinetic, empirical correlation of pyrolysis and is capable of predicting hydrogen yield in the presence of sorbent CaO. The model can also be used as a useful tool to investigate the influence of process parameters including steam/biomass ratio, CaO/fuel ratio (CaO/Fuel), and gasification temperature on hydrogen efficiency, CO2 capture ratio (CCR), and average carbonation conversion (Save). Similar to hydrogen formation, CCR also increases with increasing CaO/Fuel, but an opposite trend is exhibited in Save. Model predictions were compared with available data from the literature, which showed fairly good agreement.

  9. Hydrogen gas sensor based on long-range surface plasmons in lossy palladium film placed on photonic crystal stack

    NASA Astrophysics Data System (ADS)

    Hamidi, S. M.; Ramezani, R.; Bananej, A.

    2016-03-01

    Nanostructured plasmonic H2 gas sensor has been designed and fabricated by palladium nanostructure onto one-dimensional photonic crystal. Our one dimensional photonic crystal has been designed and fabricated to have photonic band gap in visible spectrum and the palladium nanostructure has been designed and constructed as 11 nm thin film onto the above mentioned photonic crystal. All of fabrication processes have been done in vacuum chamber by the aid of electron gun and sputtering deposition methods. The ability of the devise as a Hydrogen gas sensor has been examined by recording the long range surface Plasmon resonance in different injection of H2 gas and our results show that this sensor head can be used to sense very little amount of H2 gas in ambient at room temperature. A reversible red shift of the reflectance deep of long range surface Plasmon resonance make this sensor as a good and useful device in medical, safety and energy related materials.

  10. TiO{sub 2}/PANI And MWNT/PANI Composites Thin Films For Hydrogen Gas Sensing

    SciTech Connect

    Srivastava, Subodh; Kumar, Sumit; Agrawal, Shweta; Saxena, Arpita; Choudhary, B. L.; Mathur, Shubhra; Singh, M.; Vijay, Y. K.

    2010-12-01

    The MWNT and TiO{sub 2} doped Polyaniline (PANI) composites were synthesized by In-situ chemical oxidative polymerization method at low temperature. The MWNT/PANI and TiO{sub 2}/PANI composite thin films were prepared using spin coating method onto finger type interdigited electrodes to develop the chemiresistor type gas sensor for hydrogen gas sensing application. It was observed that the MWNT and TiO{sub 2} doped PANI composite thin films show a higher response in comparision to neat PANI. The structural and morphological properties of these composite films were characterized by X-Ray differaction (XRD) pattern and sccaning electrone microscopy (SEM) respectively.

  11. POLYCYCLIC AROMATIC HYDROCARBONS, IONIZED GAS, AND MOLECULAR HYDROGEN IN BRIGHTEST CLUSTER GALAXIES OF COOL-CORE CLUSTERS OF GALAXIES

    SciTech Connect

    Donahue, Megan; Mark Voit, G.; Hoffer, Aaron; De Messieres, Genevieve E.; O'Connell, Robert W.; McNamara, Brian R.; Nulsen, Paul E. J. E-mail: voit@pa.msu.edu

    2011-05-01

    We present measurements of 5-25 {mu}m emission features of brightest cluster galaxies (BCGs) with strong optical emission lines in a sample of nine cool-core clusters of galaxies observed with the Infrared Spectrograph on board the Spitzer Space Telescope. These systems provide a view of dusty molecular gas and star formation, surrounded by dense, X-ray-emitting intracluster gas. Past work has shown that BCGs in cool-core clusters may host powerful radio sources, luminous optical emission-line systems, and excess UV, while BCGs in other clusters never show this activity. In this sample, we detect polycyclic aromatic hydrocarbons (PAHs), extremely luminous, rotationally excited molecular hydrogen line emission, forbidden line emission from ionized gas ([Ne II] and [Ne III]), and infrared continuum emission from warm dust and cool stars. We show here that these BCGs exhibit more luminous forbidden neon and H{sub 2} rotational line emission than star-forming galaxies with similar total infrared luminosities, as well as somewhat higher ratios of 70 {mu}m/24 {mu}m luminosities. Our analysis suggests that while star formation processes dominate the heating of the dust and PAHs, a heating process consistent with suprathermal electron heating from the hot gas, distinct from star formation, is heating the molecular gas and contributing to the heating of the ionized gas in the galaxies. The survival of PAHs and dust suggests that dusty gas is somehow shielded from significant interaction with the X-ray gas.

  12. Giant Zn14 molecular building block in hydrogen-bonded network with permanent porosity for gas uptake.

    PubMed

    Mondal, Suvendu Sekhar; Bhunia, Asamanjoy; Kelling, Alexandra; Schilde, Uwe; Janiak, Christoph; Holdt, Hans-Jürgen

    2014-01-01

    In situ imidazolate-4,5-diamide-2-olate linker generation leads to the formation of a [Zn14(L2)12(O)(OH)2(H2O)4] molecular building block (MBB) with a Zn6 octahedron inscribed in a Zn8 cube. The MBBs connect by amide-amide hydrogen bonds to a 3D robust supramolecular network which can be activated for N2, CO2, CH4, and H2 gas sorption.

  13. Hydrogen stable isotopic constraints on methane emissions from oil and gas extraction in the Colorado Front Range, USA

    NASA Astrophysics Data System (ADS)

    Townsend-Small, A.; Botner, E. C.; Jimenez, K.; Blake, N. J.; Schroeder, J.; Meinardi, S.; Barletta, B.; Simpson, I. J.; Blake, D. R.; Flocke, F. M.; Pfister, G.; Bon, D.; Crawford, J. H.

    2015-12-01

    The climatic implications of a shift from oil and coal to natural gas depend on the magnitude of fugitive emissions of methane from the natural gas supply chain. Attempts to constrain methane emissions from natural gas production regions can be confounded by other sources of methane. Here we demonstrate the utility of stable isotopes, particularly hydrogen isotopes, for source apportionment of methane emissions. The Denver, Colorado area is home to a large oil and gas field with both conventional oil and gas wells and newer hydraulic fracturing wells. The region also has a large metropolitan area with several landfills and a sizable cattle population. As part of the DISCOVER-AQ and FRAPPE field campaigns in summer 2014, we collected three types of canister samples for analysis of stable isotopic composition of methane: 1), samples from methane sources; 2), samples from two stationary ground sites, one in the Denver foothills, and one in an oil and gas field; and 3), from the NCAR C-130 aircraft in samples upwind and downwind of the region. Our results indicate that hydrogen isotope ratios are excellent tracers of sources of methane in the region, as we have shown previously in California and Texas. Use of carbon isotope ratios is complicated by the similarity of natural gas isotope ratios to that of background methane. Our results indicate that, despite the large amount of natural gas production in the region, biological sources such as cattle feedlots and landfills account for at least 50% of total methane emissions in the Front Range. Future work includes comparison of isotopes and alkane ratios as tracers of methane sources, and calculation of total methane fluxes in the region using continuous measurements of methane concentrations during aircraft flights.

  14. Adding value to coal as feedstock for a hydrogen plant

    SciTech Connect

    Lackner, K.; Butt, D.; Jensen, R.; Ziock, H.

    1997-11-01

    Coal is the largest fossil energy resource and, in spite of its 19th century image, coal has proven itself in the last quarter of the 20th century as a modern and remarkably cost-effective fuel for generating electric power. Today, with increasing concern over greenhouse gases, coal needs to overcome the obstacle of being the most carbon intensive energy source there is. To clear this hurdle and provide a modern and environmentally viable energy resource based on abundant coal reserves is the goal of Vision 21. The strategy of Vision 21 rests on the production of high quality gaseous fuels like hydrogen that could either leave the plant or be used in the production of electricity by highly efficient fuel cell stacks. Here the authors outline three processing steps, that combined or separately can greatly reduce greenhouse gas emissions from coal. First, they propose to perform the gasification and water-gas shift reaction for producing hydrogen from coal with calcium oxide as a getter for carbon dioxide. This provides an efficient means to collect the carbon dioxide for reuse or disposal. Simultaneously, the carbonation facilitates the formation of hydrogen and provides the energy necessary to drive the hydrogen producing reaction to completion. In the second step, the calcium oxide would be regenerated either by a conventional calcination process or, as they propose to investigate, in a solar furnace. The latter approach would lead to a novel hybrid solar/fossil power plant that derives about 30% of its energy output from solar energy. Finally, they propose to develop a solar driven process, that generates methanol from waste carbon dioxide. In a photolytic process, CO{sub 2} is broken up into CO and O{sub 2}. The CO is then reacted with water in a conventional process to form methanol.

  15. Development Program of IS Process Pilot Test Plant for Hydrogen Production With High-Temperature Gas-Cooled Reactor

    SciTech Connect

    Jin Iwatsuki; Atsuhiko Terada; Hiroyuki Noguchi; Yoshiyuki Imai; Masanori Ijichi; Akihiro Kanagawa; Hiroyuki Ota; Shinji Kubo; Kaoru Onuki; Ryutaro Hino

    2006-07-01

    At the present time, we are alarmed by depletion of fossil energy and effects on global environment such as acid rain and global warming, because our lives depend still heavily on fossil energy. So, it is universally recognized that hydrogen is one of the best energy media and its demand will be increased greatly in the near future. In Japan, the Basic Plan for Energy Supply and Demand based on the Basic Law on Energy Policy Making was decided upon by the Cabinet on 6 October, 2003. In the plan, efforts for hydrogen energy utilization were expressed as follows; hydrogen is a clean energy carrier without carbon dioxide (CO{sub 2}) emission, and commercialization of hydrogen production system using nuclear, solar and biomass, not fossil fuels, is desired. However, it is necessary to develop suitable technology to produce hydrogen without CO{sub 2} emission from a view point of global environmental protection, since little hydrogen exists naturally. Hydrogen production from water using nuclear energy, especially the high-temperature gas-cooled reactor (HTGR), is one of the most attractive solutions for the environmental issue, because HTGR hydrogen production by water splitting methods such as a thermochemical iodine-sulfur (IS) process has a high possibility to produce hydrogen effectively and economically. The Japan Atomic Energy Agency (JAEA) has been conducting the HTTR (High-Temperature Engineering Test Reactor) project from the view to establishing technology base on HTGR and also on the IS process. In the IS process, raw material, water, is to be reacted with iodine (I{sub 2}) and sulfur dioxide (SO{sub 2}) to produce hydrogen iodide (HI) and sulfuric acid (H{sub 2}SO{sub 4}), the so-called Bunsen reaction, which are then decomposed endo-thermically to produce hydrogen (H{sub 2}) and oxygen (O{sub 2}), respectively. Iodine and sulfur dioxide produced in the decomposition reactions can be used again as the reactants in the Bunsen reaction. In JAEA, continuous

  16. Life cycle assessment of hydrogen production from S-I thermochemical process coupled to a high temperature gas reactor

    SciTech Connect

    Giraldi, M. R.; Francois, J. L.; Castro-Uriegas, D.

    2012-07-01

    The purpose of this paper is to quantify the greenhouse gas (GHG) emissions associated to the hydrogen produced by the sulfur-iodine thermochemical process, coupled to a high temperature nuclear reactor, and to compare the results with other life cycle analysis (LCA) studies on hydrogen production technologies, both conventional and emerging. The LCA tool was used to quantify the impacts associated with climate change. The product system was defined by the following steps: (i) extraction and manufacturing of raw materials (upstream flows), (U) external energy supplied to the system, (iii) nuclear power plant, and (iv) hydrogen production plant. Particular attention was focused to those processes where there was limited information from literature about inventory data, as the TRISO fuel manufacture, and the production of iodine. The results show that the electric power, supplied to the hydrogen plant, is a sensitive parameter for GHG emissions. When the nuclear power plant supplied the electrical power, low GHG emissions were obtained. These results improve those reported by conventional hydrogen production methods, such as steam reforming. (authors)

  17. The rate-limiting mechanism of transition metal gettering in multicrystalline silicon

    SciTech Connect

    McHugo, S.A.; Thompson, A.C.; Imaizumi, M.

    1997-04-01

    Multicrystalline silicon is a very interesting material for terrestrial solar cells. Its low cost and respectable energy conversion efficiency (12-15%) makes it arguably the most cost competitive material for large-volume solar power generation. However, the solar cell efficiency of this material is severely degraded by regions of high minority carrier recombination which have been shown to possess both dislocations and microdefects. These structural defects are known to increase in recombination activity with transition metal decoration. Therefore, gettering of metal impurities from the material would be expected to greatly enhance solar cell performance. Contrary to this rationale, experiments using frontside phosphorus and/or backside aluminum treatments have been found to improve regions with low recombination activity while having little or no effect on the high recombination regions and in turn only slightly improving the overall cell performance. The goal of this research is to determine the mechanism by which gettering is ineffectual on these high recombination regions. The authors have performed studies on integrated circuit (IC) quality single crystal and multicrystalline solar cell silicon (mc-silicon) in the as-grown state and after a variety of processing/gettering steps. With Surface Photovoltage measurements of the minority carrier diffusion length which is inversely proportional to carrier recombination, they have seen that aluminum gettering is effective for improving IC quality material but ineffective for improving the regions of initially low diffusion lengths (high recombination rates) in mc-silicon. Of particular interest is the great increase in diffusion length for IC material as compared to the mc-silicon. Clearly the IC material has benefited to a greater extent from the gettering procedure than the mc-silicon.

  18. Biotransformation of furanic and phenolic compounds with hydrogen gas production in a microbial electrolysis cell

    DOE PAGES

    Zeng, Xiaofei; Borole, Abhijeet P.; Pavlostathis, Spyros G.

    2015-10-27

    In this study, furanic and phenolic compounds are problematic byproducts resulting from the decomposition of lignocellulosic biomass during biofuel production. This study assessed the capacity of a microbial electrolysis cell (MEC) to produce hydrogen gas (H2) using a mixture of two furanic (furfural, FF; 5-hydroxymethyl furfural, HMF) and three phenolic (syringic acid, SA; vanillic acid, VA; and 4-hydroxybenzoic acid, HBA) compounds as the sole carbon and energy source in the bioanode. The rate and extent of biotransformation of the five compounds, efficiency of H2 production, as well as the anode microbial community structure were investigated. The five compounds were completelymore » transformed within 7-day batch runs and their biotransformation rate increased with increasing initial concentration. At an initial concentration of 1,200 mg/L (8.7 mM) of the mixture of the five compounds, their biotransformation rate ranged from 0.85 to 2.34 mM/d. The anode coulombic efficiency was 44-69%, which is comparable to wastewater-fed MECs. The H2 yield varied from 0.26 to 0.42 g H2-COD/g COD removed in the anode, and the bioanode volume-normalized H2 production rate was 0.07-0.1 L/L-d. The major identified fermentation products that did not transform further were catechol and phenol. Acetate was the direct substrate for exoelectrogenesis. Current and H2 production were inhibited at an initial substrate concentration of 1,200 mg/L, resulting in acetate accumulation at a much higher level than that measured in other batch runs conducted with a lower initial concentration of the five compounds. The anode microbial community consisted of exoelectrogens, putative degraders of the five compounds, and syntrophic partners of exoelectrogens. The H2 production route demonstrated in this study has proven to be an alternative to the currently used process of reforming natural gas to supply H2 needed to upgrade bio-oils to stable hydrocarbon fuels.« less

  19. Biotransformation of furanic and phenolic compounds with hydrogen gas production in a microbial electrolysis cell

    SciTech Connect

    Zeng, Xiaofei; Borole, Abhijeet P.; Pavlostathis, Spyros G.

    2015-10-27

    In this study, furanic and phenolic compounds are problematic byproducts resulting from the decomposition of lignocellulosic biomass during biofuel production. This study assessed the capacity of a microbial electrolysis cell (MEC) to produce hydrogen gas (H2) using a mixture of two furanic (furfural, FF; 5-hydroxymethyl furfural, HMF) and three phenolic (syringic acid, SA; vanillic acid, VA; and 4-hydroxybenzoic acid, HBA) compounds as the sole carbon and energy source in the bioanode. The rate and extent of biotransformation of the five compounds, efficiency of H2 production, as well as the anode microbial community structure were investigated. The five compounds were completely transformed within 7-day batch runs and their biotransformation rate increased with increasing initial concentration. At an initial concentration of 1,200 mg/L (8.7 mM) of the mixture of the five compounds, their biotransformation rate ranged from 0.85 to 2.34 mM/d. The anode coulombic efficiency was 44-69%, which is comparable to wastewater-fed MECs. The H2 yield varied from 0.26 to 0.42 g H2-COD/g COD removed in the anode, and the bioanode volume-normalized H2 production rate was 0.07-0.1 L/L-d. The major identified fermentation products that did not transform further were catechol and phenol. Acetate was the direct substrate for exoelectrogenesis. Current and H2 production were inhibited at an initial substrate concentration of 1,200 mg/L, resulting in acetate accumulation at a much higher level than that measured in other batch runs conducted with a lower initial concentration of the five compounds. The anode microbial community consisted of exoelectrogens, putative degraders of the five compounds, and syntrophic partners of exoelectrogens. The H2 production route demonstrated in this study has proven to be an alternative to the currently used process of reforming natural gas to supply H2 needed to

  20. Operation of a cw rf driven ion source with hydrogen and deuterium gas{sup a}

    SciTech Connect

    Melnychuk, S.T.; Debiak, T.W.; Sredniawski, J.J.

    1996-04-01

    We will describe the operation of a cw rf driven multicusp ion source designed for extraction of high current hydrogen and deuterium beams. The source is driven at 2 MHz by a 2.5 turn induction antenna immersed in the plasma. Bare stainless-steel and porcelain-coated Cu antennas have been used. The plasma load is matched to the rf generator by a variable tap {ital N}:1 transformer isolated to 46 kV, and an LC network on the secondary. With H{sub 2} gas the source can be operated at pressures between 5 and 60 mT with power reflection coefficients {lt}0.01. The extracted ion current density with a porcelain-coated antenna is approximately given by 35 mA/cm{sup 2}/kW with an 80 G dipole filter field for input powers from 3.5 to 6.6 kW. The current density remained constant for operation with a 6 and an 8 mm aperture. The source has been operated for 260 h at 3.6 kW with a single-porcelain-coated antenna. Mass spectrometer measurements of the extracted beam at this power show a species mix for H{sup +}:H{sup +}{sub 2}:H{sup +}{sub 3}:OH{sup +} of 0.49: 0.04: 0.42: 0.04. The calculated beam divergence using the IGUN code is compared with the measured divergence from an electrostatic sweep emittance scanner designed for high-power cw beam diagnostics. Phase space measurements at 40 kV and 23 mA beam current result in a normalized rms emittance of 0.09 {pi}mmmrad. {copyright} {ital 1996 American Institute of Physics.}