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Sample records for catalytic hot gas

  1. Catalytic hot gas cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Simell, P. [VTT Energy, Espoo (Finland)

    1996-12-31

    Gasification gas that contains particulates can be purified from tars and ammonia by using nickel monolith catalysts. Temperatures over 900 deg C are required at 20 bar pressure to avoid deactivation by H{sub 2}S and carbon. Dolomites and limestones are effective tar decomposing catalysts only when calcined. Tar decomposition in gasification conditions can take place by steam or dry (CO{sub 2}) reforming reactions. These reactions follow apparent first order kinetics with respect to hydrocarbons in gasification conditions. (author) (16 refs.)

  2. Catalytic hot gas cleaning of gasification gas

    Energy Technology Data Exchange (ETDEWEB)

    Simell, P. [VTT Energy, Espoo (Finland). Energy Production Technologies

    1997-12-31

    The aim of this work was to study the catalytic cleaning of gasification gas from tars and ammonia. In addition, factors influencing catalytic activity in industrial applications were studied, as well as the effects of different operation conditions and limits. Also the catalytic reactions of tar and ammonia with gasification gas components were studied. The activities of different catalyst materials were measured with laboratory-scale reactors fed by slip streams taken from updraft and fluid bed gasifiers. Carbonate rocks and nickel catalysts proved to be active tar decomposing catalysts. Ammonia decomposition was in turn facilitated by nickel catalysts and iron materials like iron sinter and iron dolomite. Temperatures over 850 deg C were required at 2000{sup -1} space velocity at ambient pressure to achieve almost complete conversions. During catalytic reactions H{sub 2} and CO were formed and H{sub 2}O was consumed in addition to decomposing hydrocarbons and ammonia. Equilibrium gas composition was almost achieved with nickel catalysts at 900 deg C. No deactivation by H{sub 2}S or carbon took place in these conditions. Catalyst blocking by particulates was avoided by using a monolith type of catalyst. The apparent first order kinetic parameters were determined for the most active materials. The activities of dolomite, nickel catalyst and reference materials were measured in different gas atmospheres using laboratory apparatus. This consisted of nitrogen carrier, toluene as tar model compound, ammonia and one of the components H{sub 2}, H{sub 2}O, CO, CO{sub 2}, CO{sub 2}+H{sub 2}O or CO+CO{sub 2}. Also synthetic gasification gas was used. With the dolomite and nickel catalyst the highest toluene decomposition rates were measured with CO{sub 2} and H{sub 2}O. In gasification gas, however, the rate was retarded due to inhibition by reaction products (CO, H{sub 2}, CO{sub 2}). Tar decomposition over dolomite was modelled by benzene reactions with CO{sub 2}, H

  3. Hydrogen production from simulated hot coke oven gas by catalytic reforming over Ni/Mg(A1)O catalysts

    Institute of Scientific and Technical Information of China (English)

    Hongwei Cheng; Baohua Yue; Xueguang Wang; Xionggang Lu; Weizhong Ding

    2009-01-01

    Hydrogen production by catalytic reforming of simulated hot coke oven gas (HCOG) with toluene as a model tar compound was investigated in a fixed bed reactor over Ni/Mg(Al)O catalysts. The catalysts were prepared by a homogeneous precipitation method using urea hydrolysis and characterized by ICP,BET, XRD, TPR, TEM and TG. XRD showed that the hydrotalcite type precursor after calcination formed (Ni,Mg)Al2O4 spinel and Ni-Mg-O solid solution structure. TPR results suggested that the increase in Ni/Mg molar ratio gave rise to the decrease in the reduction temperature of Ni2+ to Ni0 on Ni/Mg(Al)O catalysts. The reaction results indicated that toluene and CH4 could completely be converted to H2 and CO in the catalytic reforming of the simulated HCOG under atmospheric pressure and the amount of H2 in the reaction effluent gas was about 4 times more than that in original HCOG. The catalysts with lower Ni/Mg molar ratio showed better catalytic activity and resistance to ceking, which may become promising catalysts in the catalytic reforming of HCOG.

  4. Removal of ammonia from producer gas in biomass gasification: integration of gasification optimisation and hot catalytic gas cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Hongrapipat, Janjira; Saw, Woei-Lean; Pang, Shusheng [University of Canterbury, Department of Chemical and Process Engineering, Christchurch (New Zealand)

    2012-12-15

    Ammonia (NH{sub 3}) is one of the main contaminants in the biomass gasification producer gas, which is undesirable in downstream applications, and thus must be removed. When the producer gas is used in integrated gasification combined cycle (IGCC) technology, NH{sub 3} is the main precursor of nitrogen oxides (NO{sub x}) formed in gas turbine, whereas in Fischer-Tropsch synthesis and in integrated gasification fuel cell (IGFC) technology, the NH{sub 3} gas poisons the catalysts employed. This paper presents a critical review on the recent development in the understanding of the NH{sub 3} formation in biomass gasification process and in the NH{sub 3} gas cleaning technologies. The NH{sub 3} gas concentration in the producer gas can firstly be reduced by the primary measures taken in the gasification process by operation optimisation and using in-bed catalytic materials. Further removal of the NH{sub 3} gas can be implemented by the secondary measures introduced in the post-gasification gas-cleaning process. Focus is given on the catalytic gas cleaning in the secondary measures and its advantages are analysed including energy efficiency, impacts on environment and recyclability of the catalyst. Based on the review, the most effective cleaning process is proposed with integration of both the primary and the secondary measures for application in a biomass gasification process. (orig.)

  5. Catalytic reforming of model tar compounds from hot coke oven gas with low steam/carbon ratio over Ni/MgO-Al{sub 2}O{sub 3} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Baohua [Department of Chemistry, College of Sciences, Shanghai University, Shanghai 200444 (China); Wang, Xueguang; Ai, Xinpeng; Yang, Jun; Li, Lin; Lu, Xionggang; Ding, Weizhong [Shanghai Key Laboratory of Modern Metallurgy and Material Processing, Shanghai University, Yanchang Road No.149, Shanghai 200072 (China)

    2010-09-15

    The catalytic reforming of toluene and naphthalene was performed to investigate the possibility for directly converting tar components from hot coke oven gas (COG) with lower steam/carbon (S/C) molar ratios to light fuel gases. The NiO/MgO-Al{sub 2}O{sub 3} catalysts reduced exhibited excellent catalytic activity, stability and sulphur tolerance. The effects of various reaction conditions and S/C ratios on the catalytic performance were investigated in detail. Toluene and naphthalene were completely converted into small gas molecules at 700-800 C and S/C = 0.28. An appropriate amount of steam benefited the methanation reaction of CO and H{sub 2}. The effects of N{sub 2}, CH{sub 4} or CO in COG were also discussed. Relative to N{sub 2}, CO contributed to the conversion of toluene and the formation of CH{sub 4}, but the opposite was true for CH{sub 4}. The sulphur tolerance was tested by adding H{sub 2}S in the feed gas. The reaction results were explained by a water cycle mechanism. (author)

  6. ADVANCED HOT GAS FILTER DEVELOPMENT

    Energy Technology Data Exchange (ETDEWEB)

    E.S. Connolly; G.D. Forsythe

    1998-12-22

    Advanced, coal-based power plants will require durable and reliable hot gas filtration systems to remove particulate contaminants from the gas streams to protect downstream components such as turbine blades from erosion damage. It is expected that the filter elements in these systems will have to be made of ceramic materials to withstand goal service temperatures of 1600 F or higher. Recent demonstration projects and pilot plant tests have indicated that the current generation of ceramic hot gas filters (cross-flow and candle configurations) are failing prematurely. Two of the most promising materials that have been extensively evaluated are clay-bonded silicon carbide and alumina-mullite porous monoliths. These candidates, however, have been found to suffer progressive thermal shock fatigue damage, as a result of rapid cooling/heating cycles. Such temperature changes occur when the hot filters are back-pulsed with cooler gas to clean them, or in process upset conditions, where even larger gas temperature changes may occur quickly and unpredictably. In addition, the clay-bonded silicon carbide materials are susceptible to chemical attack of the glassy binder phase that holds the SiC particles together, resulting in softening, strength loss, creep, and eventual failure.

  7. Temperature Modulation of a Catalytic Gas Sensor

    OpenAIRE

    Eike Brauns; Eva Morsbach; Sebastian Kunz; Marcus Baeumer; Walter Lang

    2014-01-01

    The use of catalytic gas sensors usually offers low selectivity, only based on their different sensitivities for various gases due to their different heats of reaction. Furthermore, the identification of the gas present is not possible, which leads to possible misinterpretation of the sensor signals. The use of micro-machined catalytic gas sensors offers great advantages regarding the response time, which allows advanced analysis of the sensor response. By using temperature modulation, additi...

  8. Hot-electron-mediated surface chemistry: toward electronic control of catalytic activity.

    Science.gov (United States)

    Park, Jeong Young; Kim, Sun Mi; Lee, Hyosun; Nedrygailov, Ievgen I

    2015-08-18

    Energy dissipation at surfaces and interfaces is mediated by excitation of elementary processes, including phonons and electronic excitation, once external energy is deposited to the surface during exothermic chemical processes. Nonadiabatic electronic excitation in exothermic catalytic reactions results in the flow of energetic electrons with an energy of 1-3 eV when chemical energy is converted to electron flow on a short (femtosecond) time scale before atomic vibration adiabatically dissipates the energy (in picoseconds). These energetic electrons that are not in thermal equilibrium with the metal atoms are called "hot electrons". The detection of hot electron flow under atomic or molecular processes and understanding its role in chemical reactions have been major topics in surface chemistry. Recent studies have demonstrated electronic excitation produced during atomic or molecular processes on surfaces, and the influence of hot electrons on atomic and molecular processes. We outline research efforts aimed at identification of the intrinsic relation between the flow of hot electrons and catalytic reactions. We show various strategies for detection and use of hot electrons generated by the energy dissipation processes in surface chemical reactions and photon absorption. A Schottky barrier localized at the metal-oxide interface of either catalytic nanodiodes or hybrid nanocatalysts allows hot electrons to irreversibly transport through the interface. We show that the chemicurrent, composed of hot electrons excited by the surface reaction of CO oxidation or hydrogen oxidation, correlates well with the turnover rate measured separately by gas chromatography. Furthermore, we show that hot electron flows generated on a gold thin film by photon absorption (or internal photoemission) can be amplified by localized surface plasmon resonance. The influence of hot charge carriers on the chemistry at the metal-oxide interface are discussed for the cases of Au, Ag, and Pt

  9. Process for catalytic flue gas denoxing

    International Nuclear Information System (INIS)

    With the increasing concern for the environment, stringency of legislation and industry's awareness of its own environmental responsibility, the demand for the reduction of emission levels of nitrogen oxides is becoming increasingly urgent. This paper reports that Shell has developed a low temperature catalytic deNOx system for deep removal of nitrogen oxides, which includes a low-pressure-drop reactor. This process is able to achieve over 90% removal of nitrogen oxides and therefore can be expected to meet legislation requirements for the coming years. The development of a low-temperature catalyst makes it possible to operate at temperatures as low as 120 degrees C, compared to 300-400 degrees C for the conventional honeycomb and plate-type catalysts. This allows an add-on construction, which is most often a more economical solution than the retrofits in the hot section required with conventional deNOx catalysts. The Lateral Flow Reactor (LFR), which is used for dust-free flue gas applications, and the Parallel Passage Reactor (PPR) for dust-containing flue gas applications, have been developed to work with pressure drops below 10 mbar

  10. ADVANCED HOT GAS FILTER DEVELOPMENT

    Energy Technology Data Exchange (ETDEWEB)

    E.S. Connolly; G.D. Forsythe

    2000-09-30

    DuPont Lanxide Composites, Inc. undertook a sixty-month program, under DOE Contract DEAC21-94MC31214, in order to develop hot gas candle filters from a patented material technology know as PRD-66. The goal of this program was to extend the development of this material as a filter element and fully assess the capability of this technology to meet the needs of Pressurized Fluidized Bed Combustion (PFBC) and Integrated Gasification Combined Cycle (IGCC) power generation systems at commercial scale. The principal objective of Task 3 was to build on the initial PRD-66 filter development, optimize its structure, and evaluate basic material properties relevant to the hot gas filter application. Initially, this consisted of an evaluation of an advanced filament-wound core structure that had been designed to produce an effective bulk filter underneath the barrier filter formed by the outer membrane. The basic material properties to be evaluated (as established by the DOE/METC materials working group) would include mechanical, thermal, and fracture toughness parameters for both new and used material, for the purpose of building a material database consistent with what is being done for the alternative candle filter systems. Task 3 was later expanded to include analysis of PRD-66 candle filters, which had been exposed to actual PFBC conditions, development of an improved membrane, and installation of equipment necessary for the processing of a modified composition. Task 4 would address essential technical issues involving the scale-up of PRD-66 candle filter manufacturing from prototype production to commercial scale manufacturing. The focus would be on capacity (as it affects the ability to deliver commercial order quantities), process specification (as it affects yields, quality, and costs), and manufacturing systems (e.g. QA/QC, materials handling, parts flow, and cost data acquisition). Any filters fabricated during this task would be used for product qualification tests

  11. Hot Gas in the Large Magellanic Cloud

    Science.gov (United States)

    Chu, You-Hua

    2000-01-01

    The Large Magellanic Cloud (LMC) offers an excellent laboratory to study the physical structure of the interstellar medium (ISM) because of its proximity, nearly face-on orientation, and small foreground and internal extinction. Optical and radio surveys of the LMC ISM have revealed interstellar structures of sizes ranging from a few parsecs to over 1000 parsecs. ROSAT X-ray mosaics of the LMC have detected abundant 10 (exp 6) K hot gas, some of which is bounded by large shell structures while the rest, does not appear to be associated with any visible interstellar structure. The X-ray observations have been analyzed to determine the physical conditions of the hot gas. The distribution of the hot gas can be compared to those of the cooler gas and massive stars, in order to determine the production mechanism of the hot gas. UV observations of interstellar absorption lines of high ions, such as C IV, N V, and O VI, can be used to study the interfaces between the 10 (exp 6) K gas and cooler ionized gas, and to provide constraints on the location of 10 (exp 6) K gas with respect to the cooler gas along the line of sight.

  12. Catalytic combustion in gas stoves - Phase II

    Energy Technology Data Exchange (ETDEWEB)

    Hjelm, Anna-Karin [CATATOR AB, Lund (Sweden)

    2003-06-01

    Several independent studies show that gas stoves to some degree contribute to the indoor emissions of NO{sub x} especially in situations were the ventilation flow is poor. The peak-NO{sub x} concentrations can reach several hundred ppb but the integral concentration seldom exceeds about 20 - 50 ppb, which corresponds to an indoor-outdoor ratio of about 1 - 2.5. Epidemiological studies indicate increasing problems with respiratory symptoms in sensitive people at concentrations as low as 15 ppb of NO{sub 2}. Consequently, the NO{sub x}-concentration in homes where gas stoves are used is high enough to cause health effects. However, in situations where the ventilation flow is high (utilisation of ventilation hoods) the NO{sub x}-emissions are not likely to cause any health problems. This study has been aimed at investigating the possibilities to reduce the NO{sub x} emissions from gas stoves by replacing the conventional flame combustion with catalytic combustion. The investigation is requested by Swedish Gas Center, and is a following-up work of an earlier conducted feasibility study presented in April-2002. The present investigation reports on the possibility to use cheap and simple retro-fit catalytic design suggestions for traditional gas stoves. Experiments have been conducted with both natural and town gas, and parameters such as emissions of NO{sub x}, CO and unburned fuel gas and thermal efficiency, etc, have been examined and are discussed. The results show that it is possible to reduce the NO{sub x} emissions up to 80% by a simple retro-fit installation, without decreasing the thermal efficiency of the cooking plate. The measured source strengths correspond to indoor NO{sub x} concentrations that are below or equal to the average outdoor concentration, implying that no additional detrimental health effects are probable. The drawback of the suggested installations is that the concentration of CO and in some cases also CH{sub 4} are increased in the flue gases

  13. Hot-Gas Filter Ash Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Swanson, M.L.; Hurley, J.P.; Dockter, B.A.; O`Keefe, C.A.

    1997-07-01

    Large-scale hot-gas filter testing over the past 10 years has revealed numerous cases of cake buildup on filter elements that has been difficult, if not impossible, to remove. At times, the cake can blind or bridge between candle filters, leading to filter failure. Physical factors, including particle-size distribution, particle shape, the aerodynamics of deposition, and system temperature, contribute to the difficulty in removing the cake, but chemical factors such as surface composition and gas-solid reactions also play roles in helping to bond the ash to the filters or to itself. This project is designed to perform the research necessary to determine the fuel-, sorbent-, and operations-related conditions that lead to blinding or bridging of hot-gas particle filters. The objectives of the project are threefold: (1) Determine the mechanisms by which a difficult-to-clean ash is formed and how it bridges hot-gas filters (2) Develop a method to determine the rate of bridging based on analyses of the feed coal and sorbent, filter properties, and system operating conditions and (3) Suggest and test ways to prevent filter bridging.

  14. Fast cold gas in hot AGN outflows

    CERN Document Server

    Costa, Tiago; Haehnelt, Martin

    2014-01-01

    Observations of the emission from spatially extended cold gas around bright high-redshift QSOs reveal surprisingly large velocity widths exceeding 2000 km s^(-1), out to projected distances as large as 30 kpc. The high velocity widths have been interpreted as the signature of powerful AGN-driven outflows. Naively, these findings appear in tension with hydrodynamic models in which AGN-driven outflows are energy-driven and thus very hot with typical temperatures T = 10^6-7 K. Using the moving-mesh code Arepo, we perform 'zoom-in' cosmological simulations of a z = 6 QSO and its environment, following black hole growth and feedback via energy-driven outflows. In the simulations, the QSO host galaxy is surrounded by a clumpy circum-galactic medium pre-enriched with metals due to supernovae-driven galactic outflows. As a result, part of the AGN-driven hot outflowing gas can cool radiatively, leading to large amounts (> 10^9 M_sun) of cold gas comoving with the hot bipolar outflow. This results in velocity widths of...

  15. Hot and Turbulent Gas in Clusters

    CERN Document Server

    Schmidt, Wolfram; Niemeyer, Jens C; Almgren, Ann S

    2016-01-01

    The gas in galaxy clusters is heated by shock compression through accretion (outer shocks) and mergers (inner shocks). These processes additionally produce turbulence. To analyse the relation between the thermal and turbulent energies of the gas under the influence of non-adiabatic processes, we performed numerical simulations of cosmic structure formation in a box of 152 Mpc comoving size with radiative cooling, UV background, and a subgrid scale model for numerically unresolved turbulence. By smoothing the gas velocities with an adaptive Kalman filter, we are able to estimate bulk flows toward cluster cores. This enables us to infer the velocity dispersion associated with the turbulent fluctuation relative to the bulk flow. For halos with masses above $10^{13}\\,M_\\odot$, we find that the turbulent velocity dispersions averaged over the warm-hot intergalactic medium (WHIM) and the intracluster medium (ICM) are approximately given by powers of the mean gas temperatures with exponents around 0.5, corresponding...

  16. METC CFD simulations of hot gas filtration

    Energy Technology Data Exchange (ETDEWEB)

    O`Brien, T.J.

    1995-06-01

    Computational Fluid Dynamic (CFD) simulations of the fluid/particle flow in several hot gas filtration vessels will be presented. These simulations have been useful in designing filtration vessels and in diagnosing problems with filter operation. The simulations were performed using the commercial code FLUENT and the METC-developed code MFIX. Simulations of the initial configuration of the Karhula facility indicated that the dirty gas flow over the filter assemblage was very non-uniform. The force of the dirty gas inlet flow was inducing a large circulation pattern that caused flow around the candles to be in opposite directions on opposite sides of the vessel. By introducing a system of baffles, a more uniform flow pattern was developed. This modification may have contributed to the success of the project. Several simulations of configurations proposed by Industrial Filter and Pump were performed, varying the position of the inlet. A detailed resolution of the geometry of the candles allowed determination of the flow between the individual candles. Recent simulations in support of the METC/CeraMem Cooperative Research and Development Agreement have analyzed the flow in the vessel during the cleaning back-pulse. Visualization of experiments at the CeraMem cold-flow facility provided confidence in the use of CFD. Extensive simulations were then performed to assist in the design of the hot test facility being built by Ahlstrom/Pyropower. These tests are intended to demonstrate the CeraMem technology.

  17. Particulate hot gas stream cleanup technical issues

    Energy Technology Data Exchange (ETDEWEB)

    Pontius, D.H.; Snyder, T.R.

    1999-09-30

    The analyses of hot gas stream cleanup particulate samples and descriptions of filter performance studied under this contract were designed to address problems with filter operation that have been linked to characteristics of the collected particulate matter. One objective of this work was to generate an interactive, computerized data bank of the key physical and chemical characteristics of ash and char collected from operating advanced particle filters and to relate these characteristics to the operation and performance of these filters. The interactive data bank summarizes analyses of over 160 ash and char samples from fifteen pressurized fluidized-bed combustion and gasification facilities utilizing high-temperature, high pressure barrier filters.

  18. Hot-Gas Filter Ash Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Dockter, B.A.; Hurley, J.P.; Watne, T.A.; Katrinak, K.A.; O`Keefe, C.A. [North Dakota Univ., Grand Forks, ND (United States). Energy and Minerals Research Center

    1996-12-31

    Large-scale hot-gas testing over the past several years has revealed numerous cases of cake buildup on filter elements that have been difficult, if not impossible to remove. At times, the cake can bridge between candle filters, leading to high filter failure rates. Physical factors, including particle-size distribution, particle shape, the aerodynamics of deposition, and system temperature contribute to difficulty in removing the cake. It is speculated that chemical as well as physical effects are playing a role in leading the ash to bond to the filter or to itself. The Energy and Environmental research Center (EERC) at the University of North Dakota is working with Electric Power Research Institute (EPRI) and a consortium of companies in partnership with the US Department of Energy (DOE) to perform the research necessary to determine the factors that cause hot-gas cleanup filters to be blinded by ash or to develop deposits that can bridge the filters and cause them to fail. The objectives of this overall project are threefold: first, to determine the mechanisms by which difficult-to-clean ash is formed; second, to develop a method to determine the rate of blinding/bridging based on fuel and sorbent properties and operating conditions; finally, to provide suggestions fro ways to prevent filter blinding by the troublesome ash. The projects consists of four tasks: field sampling and archive sample analyses, laboratory-scale testing, bench-scale testing, and model and database development testing. This paper present preliminary data from Task 2 on determining the tensile strengths of coal ash particles at elevated temperatures and simulated combustor gas conditions.

  19. Graphene-Semiconductor Catalytic Nanodiodes for Quantitative Detection of Hot Electrons Induced by a Chemical Reaction.

    Science.gov (United States)

    Lee, Hyosun; Nedrygailov, Ievgen I; Lee, Young Keun; Lee, Changhwan; Choi, Hongkyw; Choi, Jin Sik; Choi, Choon-Gi; Park, Jeong Young

    2016-03-01

    Direct detection of hot electrons generated by exothermic surface reactions on nanocatalysts is an effective strategy to obtain insight into electronic excitation during chemical reactions. For this purpose, we fabricated a novel catalytic nanodiode based on a Schottky junction between a single layer of graphene and an n-type TiO2 layer that enables the detection of hot electron flows produced by hydrogen oxidation on Pt nanoparticles. By making a comparative analysis of data obtained from measuring the hot electron current (chemicurrent) and turnover frequency, we demonstrate that graphene's unique electronic structure and extraordinary material properties, including its atomically thin nature and ballistic electron transport, allow improved conductivity at the interface between the catalytic Pt nanoparticles and the support. Thereby, graphene-based nanodiodes offer an effective and facile way to approach the study of chemical energy conversion mechanisms in composite catalysts with carbon-based supports. PMID:26910271

  20. Advanced catalytic converter system for natural gas powered diesel engines

    Energy Technology Data Exchange (ETDEWEB)

    Strots, V.O.; Bunimovich, G.A.; Matros, Y.S. [Matros Technologies Inc., Chesterfield, Missouri (United States); Zheng, M.; Mirosh, E.A. [Alternative Fuel Systems Inc., Calgary, Alberta (Canada)

    1998-12-31

    The paper discusses the development of catalytic converter for aftertreatment of exhaust gas from diesel engines powered with natural gas. The converter, operated with periodical reversals of the flow, ensures destruction of CO and hydrocarbons, including methane. Both computer simulation and engine testing results are presented. 8 refs.

  1. Power control for hot gas engines

    Science.gov (United States)

    Macglashan, W. F. (Inventor)

    1980-01-01

    A hot gas engine in which the expander piston of the engine is connected to an expander crankshaft. A displacer piston of the engine is connected to a separate displacer crankshaft which may or may not be coaxial with the expander crankshaft. A phase angle control mechanism used as a power control for changing the phase angle between the expander and displacer crankshaft is located between the two crankshafts. The phase angle control mechanism comprises a differential type mechanism comprised of a pair of gears, as for example, bevel gears, one of which is connected to one end of the expander crankshaft and the other of which is connected to the opposite end of the displacer crankshaft. A mating bevel gear is disposed in meshing engagement with the first two level gears to provide a phase angle control between the two crankshafts. Other forms of differential mechanisms may be used including conventional spur gears connected in a differential type arrangement.

  2. Hot gas path component cooling system

    Science.gov (United States)

    Lacy, Benjamin Paul; Bunker, Ronald Scott; Itzel, Gary Michael

    2014-02-18

    A cooling system for a hot gas path component is disclosed. The cooling system may include a component layer and a cover layer. The component layer may include a first inner surface and a second outer surface. The second outer surface may define a plurality of channels. The component layer may further define a plurality of passages extending generally between the first inner surface and the second outer surface. Each of the plurality of channels may be fluidly connected to at least one of the plurality of passages. The cover layer may be situated adjacent the second outer surface of the component layer. The plurality of passages may be configured to flow a cooling medium to the plurality of channels and provide impingement cooling to the cover layer. The plurality of channels may be configured to flow cooling medium therethrough, cooling the cover layer.

  3. Development of iron-aluminide hot-gas filters

    Energy Technology Data Exchange (ETDEWEB)

    Tortorelli, P.F.; Wright, I.G.; Judkins, R.R.

    1996-06-01

    Removal of particles from hot synthesis gas produced by coal gasification is vital to the success of these systems. In Integrated [Coal] Gasification Combined Cycle systems, the synthesis gas is the fuel for gas turbines. To avoid damage to turbine components, it is necessary that particles be removed from the fuel gas prior to combustion and introduction into the turbine. Reliability and durability of the hot-gas filtering devices used to remove the particles is, of course, of special importance. Hot-gas filter materials include both ceramics and metals. Numerous considerations must be made in selecting materials for these filters. Constituents in the hot gases may potentially degrade the properties and performance of the filters to the point that they are ineffective in removing the particles. Very significant efforts have been made by DOE and others to develop effective hot-particle filters and, although improvements have been made, alternative materials and structures are still needed.

  4. OPERATING SPECIFICATIONS OF CATALYTIC CLEANING OF GAS FROM BIOMASS GASIFICATION

    Directory of Open Access Journals (Sweden)

    Martin Lisý

    2015-12-01

    Full Text Available The paper focuses on the theoretical description of the cleaning of syngas from biomass and waste gasification using catalytic methods, and on the verification of the theory through experiments. The main obstruction to using syngas from fluid gasification of organic matter is the presence of various high-boiling point hydrocarbons (i.e., tar in the gas. The elimination of tar from the gas is a key factor in subsequent use of the gas in other technologies for cogeneration of electrical energy and heat. The application of a natural or artificial catalyst for catalytic destruction of tar is one of the methods of secondary elimination of tar from syngas. In our experiments, we used a natural catalyst (dolomite or calcium magnesium carbonate from Horní Lánov with great mechanical and catalytic properties, suitable for our purposes. The advantages of natural catalysts in contrast to artificial catalysts include their availability, low purchase prices and higher resilience to the so-called catalyst poison. Natural calcium catalysts may also capture undesired compounds of sulphure and chlorine. Our paper presents a theoretical description and analysis of catalytic destruction of tar into combustible gas components, and of the impact of dolomite calcination on its efficiency. The efficiency of the technology is verified in laboratories. The facility used for verification was a 150 kW pilot gasification unit with a laboratory catalytic filter. The efficiency of tar elimination reached 99.5%, the tar concentration complied with limits for use of the gas in combustion engines, and the tar content reached approximately 35 mg/mn3. The results of the measurements conducted in laboratories helped us design a pilot technology for catalytic gas cleaning.

  5. Particulate hot gas stream cleanup technical issues

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    This is the tenth in a series of quarterly reports describing the activities performed under Contract No. DE-AC21-94MC31160. Analyses of Hot Gas Stream Cleanup (HGCU) ashes and descriptions of filter performance address aspects of filter operation that are apparently linked to the characteristics of the collected ash or the performance of the ceramic bed filter elements. Task I is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters (APFS) and to relate these ash properties to the operation and performance of these filters. Task 2 concerns testing and failure analysis of ceramic filter elements. Under Task I during the past quarter, analyses were performed on a particulate sample from the Transport Reactor Demonstration Unit (TRDU) located at the University of North Dakota Energy and Environmental Research Center. Analyses are in progress on ash samples from the Advanced Particulate Filter (APF) at the Pressurized Fluidized-Bed Combustor (PFBC) that was in operation at Tidd and ash samples from the Pressurized Circulating Fluid Bed (PCFB) system located at Karhula, Finland. A site visit was made to the Power Systems Development Facility (PSDF) to collect ash samples from the filter vessel and to document the condition of the filter vessel with still photographs and videotape. Particulate samples obtained during this visit are currently being analyzed for entry into the Hot Gas Cleanup (HGCU) data base. Preparations are being made for a review meeting on ash bridging to be held at Department of Energy Federal Energy Technology Center - Morgantown (DOE/FETC-MGN) in the near future. Most work on Task 2 was on hold pending receipt of additional funds; however, creep testing of Schumacher FT20 continued. The creep tests on Schumacher FT20 specimens just recently ended and data analysis and comparisons to other data are ongoing. A summary and analysis of these creep results will be sent out shortly. Creep

  6. ADVANCED SULFUR CONTROL CONCEPTS FOR HOT GAS DESULFURIZATION TECHNOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    1999-04-01

    The objective of this project is to develop a hot-gas desulfurization process scheme for control of H{sub 2}S in HTHP coal gas that can be more simply and economically integrated with known regenerable sorbents in DOE/METC-sponsored work than current leading hot-gas desulfurization technologies. In addition to being more economical, the process scheme to be developed must yield an elemental sulfur byproduct.

  7. ADVANCED SULFUR CONTROL CONCEPTS FOR HOT GAS DESULFURIZATION TECHNOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    None

    1998-12-31

    The objective of this project is to develop a hot-gas desulfurization process scheme for control of H{sub 2}S in HTHP coal gas that can be more simply and economically integrated with known regenerable sorbents in DOE/METC-sponsored work than current leading hot-gas desulfurization technologies. In addition to being more economical, the process scheme to be developed must yield an elemental sulfur byproduct.

  8. A catalytic distillation process for light gas oil hydrodesulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Vargas-Villamil, F.D.; Marroquin, J.O.; Paz, C. de la; Rodriguez, E. [Prog. de Matematicas Aplicadas y Computacion, Prog. de Tratamiento de Crudo Maya, Instituto Mexicano del Petroleo, Mexico City, DF (Mexico)

    2004-07-01

    A light gas oil hydrodesulfurization process via catalytic distillation is developed and compared to a conventional process. By integrating the separation and reaction into a single unit, the catalytic distillation may produce a diesel with low concentration of sulfur compounds at a lower cost than the traditional reaction/separation process. The process proposed in this work is compared to an optimised conventional hydrodesulfurization unit which represents fairly well a plant that belongs to the National System of Refineries. During the optimisation of the conventional process, a compromise is established among the production of diesel and naphtha and the operating costs. The results show that the light gas oil hydrodesulfurization via catalytic distillation is as or more efficient than the conventional process. However, the removal of the sulfur compounds is carried out under less rigorous conditions. This design reduces the fix and operational costs. (author)

  9. Catalytic destruction of tar in biomass derived producer gas

    International Nuclear Information System (INIS)

    The purpose of this study is to investigate catalytic destruction of tar formed during gasification of biomass, with the goal of improving the quality of the producer gas. This work focuses on nickel based catalysts treated with alkali in an effort to promote steam gasification of the coke that deposits on catalyst surfaces. A tar conversion system consisting of a guard bed and catalytic reactor was designed to treat the producer gas from an air blown, fluidized bed biomass gasifier. The guard bed used dolomite to crack the heavy tars. The catalytic reactor was used to evaluate three commercial steam reforming catalysts. These were the ICI46-1 catalyst from Imperial Chemical Industry and Z409 and RZ409 catalysts from Qilu Petrochemical Corp. in China. A 0.5-3 l/min slipstream from a 5 tpd biomass gasifier was used to test the tar conversion system. Gas and tar were sampled before and after the tar conversion system to evaluate the effectiveness of the system. Changes in gas composition as functions of catalytic bed temperature, space velocity and steam/TOC (total organic carbon) ratio are presented. Structural changes in the catalysts during the tests are also described

  10. Hot Gas Halos in Early-Type Field Galaxies

    CERN Document Server

    Mulchaey, John S

    2010-01-01

    We use Chandra and XMM-Newton to study the hot gas content in a sample of field early-type galaxies. We find that the L_X-L_K relationship is steeper for field galaxies than for comparable galaxies in groups and clusters. The low hot gas content of field galaxies with L_K < L_star suggests that internal processes such as supernovae driven winds or AGN feedback expel hot gas from low mass galaxies. Such mechanisms may be less effective in groups and clusters where the presence of an intragroup or intracluster medium can confine outflowing material. In addition, galaxies in groups and clusters may be able to accrete gas from the ambient medium. While there is a population of L_K < L_star galaxies in groups and clusters that retain hot gas halos, some galaxies in these rich environments, including brighter galaxies, are largely devoid of hot gas. In these cases, the hot gas halos have likely been removed via ram pressure stripping. This suggests a very complex interplay between the intragroup/intracluster ...

  11. Development of catalytic gas cleaning in gasification

    Energy Technology Data Exchange (ETDEWEB)

    Simell, P.; Kurkela, E.; Staahlberg, P.; Hepola, J. [VTT Energy, Espoo (Finland)

    1996-12-31

    Gasification gas containing dust can be efficiently purified from tars and ammonia with a nickel monolith catalyst. Temperatures of >900 deg C and a residence time of about 1 s (SV 2 500 1/h) were needed at 5 bar pressure to achieve complete tar decomposition and 80 % ammonia conversion. Catalyst deactivation was not observed during test runs of 100 h. At lower pressures dolomites and limestones can also be applied for tar removal at about 900 deg C temperatures. (orig.) 12 refs.

  12. Hydrocarbon Liquid Production from Biomass via Hot-Vapor-Filtered Fast Pyrolysis and Catalytic Hydroprocessing of the Bio-oil

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Douglas C.; Wang, Huamin; French, Richard; Deutch, Steve; Iisa, Kristiina

    2014-08-14

    Hot-vapor filtered bio-oils were produced from two different biomass feedstocks, oak and switchgrass, and the oils were evaluated in hydroprocessing tests for production of liquid hydrocarbon products. Hot-vapor filtering reduced bio-oil yields and increased gas yields. The yields of fuel carbon as bio-oil were reduced by ten percentage points by hot-vapor filtering for both feedstocks. The unfiltered bio-oils were evaluated alongside the filtered bio-oils using a fixed bed catalytic hydrotreating test. These tests showed good processing results using a two-stage catalytic hydroprocessing strategy. Equal-sized catalyst beds, a sulfided Ru on carbon catalyst bed operated at 220°C and a sulfided CoMo on alumina catalyst bed operated at 400°C were used with the entire reactor at 100 atm operating pressure. The products from the four tests were similar. The light oil phase product was fully hydrotreated so that nitrogen and sulfur were below the level of detection, while the residual oxygen ranged from 0.3 to 2.0%. The density of the products varied from 0.80 g/ml up to 0.86 g/ml over the period of the test with a correlated change of the hydrogen to carbon atomic ratio from 1.79 down to 1.57, suggesting some loss of catalyst activity through the test. These tests provided the data needed to assess the suite of liquid fuel products from the process and the activity of the catalyst in relationship to the existing catalyst lifetime barrier for the technology.

  13. Particulate hot gas stream cleanup technical issues

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    This is the eleventh in a series of quarterly reports describing the activities performed under Contract No. DE-AC21-94MC31160. Analyses of Hot Gas Stream Cleanup (HGCU) ashes and descriptions of filter performance address aspects of filter operation that are apparently linked to the characteristics of the collected ash or the performance of the ceramic bed filter elements. Task 1 is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters (APFS) and to relate these ash properties to the operation and performance of these filters. Task 2 concerns testing and failure analysis of ceramic filter elements. Under Task 1 during the past quarter, analyses were completed on samples obtained during a site visit to the Power Systems Development Facility (PSDF). Analyses are in progress on ash samples from the Advanced Particulate Filter (APF) at the Pressurized Fluidized-Bed Combustor (PFBC) that was in operation at Tidd and ash samples from the Pressurized Circulating Fluid Bed (PCFB) system located at Karhula, Finland. An additional analysis was performed on a particulate sample from the Transport Reactor Demonstration Unit (TRDU) located at the University of North Dakota Energy and Environmental Research Center. A manuscript and poster were prepared for presentation at the Advanced Coal-Based Power and Environmental Systems `97 Conference scheduled for July 22 - 24, 1997. A summary of recent project work covering the mechanisms responsible for ash deposit consolidation and ash bridging in APF`s collecting PFB ash was prepared and presented at FETC-MGN in early July. The material presented at that meeting is included in the manuscript prepared for the Contractor`s Conference and also in this report. Task 2 work during the past quarter included mechanical testing and microstructural examination of Schumacher FT20 and Pall 326 as- manufactured, after 540 hr in service at Karhula, and after 1166 hr in service at

  14. Natural gas combustion in a catalytic turbulent fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Foka, M.; Chaouki, J.; Guy, C.; Klvana, D. [Ecole Polytechnique de Montreal, Quebec (Canada). Dept. of Chemical Engineering

    1994-12-01

    Catalytic fluidized bed combustion of natural gas is shown to be an emerging technology capable of meeting all environmental constraints as far as nitrogen oxides and carbon monoxide are concerned. This technology uses powder catalysts in the turbulent flow regime where the gas-solid contact is optimal so as to maintain a high combustion efficiency. In fact, the catalytic combustion carried out in both the bubbling and the turbulent regimes at 450-500{sup o}C shows that the turbulent regime is more favorable. A single phase plug flow model with axial dispersion is shown to fit satisfactorily the data obtained at 500{sup o}C where the combustion efficiency is very good. A self-sustained combustion was achieved with a mixture of 4% methane at around 500{sup o}C with a complete conversion of methane and a zero emission of NO{sub x} and CO. (author)

  15. Industrial Gas Turbine Engine Catalytic Pilot Combustor-Prototype Testing

    Energy Technology Data Exchange (ETDEWEB)

    Etemad, Shahrokh [Precision Combustion, Inc., North Haven, CT (United States); Baird, Benjamin [Precision Combustion, Inc., North Haven, CT (United States); Alavandi, Sandeep [Precision Combustion, Inc., North Haven, CT (United States); Pfefferle, William [Precision Combustion, Inc., North Haven, CT (United States)

    2010-04-01

    PCI has developed and demonstrated its Rich Catalytic Lean-burn (RCL®) technology for industrial and utility gas turbines to meet DOE's goals of low single digit emissions. The technology offers stable combustion with extended turndown allowing ultra-low emissions without the cost of exhaust after-treatment and further increasing overall efficiency (avoidance of after-treatment losses). The objective of the work was to develop and demonstrate emission benefits of the catalytic technology to meet strict emissions regulations. Two different applications of the RCL® concept were demonstrated: RCL® catalytic pilot and Full RCL®. The RCL® catalytic pilot was designed to replace the existing pilot (a typical source of high NOx production) in the existing Dry Low NOx (DLN) injector, providing benefit of catalytic combustion while minimizing engine modification. This report discusses the development and single injector and engine testing of a set of T70 injectors equipped with RCL® pilots for natural gas applications. The overall (catalytic pilot plus main injector) program NOx target of less than 5 ppm (corrected to 15% oxygen) was achieved in the T70 engine for the complete set of conditions with engine CO emissions less than 10 ppm. Combustor acoustics were low (at or below 0.1 psi RMS) during testing. The RCL® catalytic pilot supported engine startup and shutdown process without major modification of existing engine controls. During high pressure testing, the catalytic pilot showed no incidence of flashback or autoignition while operating over a wide range of flame temperatures. In applications where lower NOx production is required (i.e. less than 3 ppm), in parallel, a Full RCL® combustor was developed that replaces the existing DLN injector providing potential for maximum emissions reduction. This concept was tested at industrial gas turbine conditions in a Solar Turbines, Incorporated high-pressure (17 atm.) combustion rig and in a modified Solar

  16. Hot particulate removal and desulfurization results from the METC integrated gasification and hot gas cleanup facility

    Energy Technology Data Exchange (ETDEWEB)

    Rockey, J.M.

    1995-06-01

    The Morgantown Energy Technology Center (METC) is conducting experimental testing using a 10-inch diameter fluid-bed gasifier (FBG) and modular hot gas cleanup rig (MGCR) to develop advanced methods for removing contaminants in hot coal gasifier gas streams for commercial development of integrated gasification combined-cycle (IGCC) power systems. The program focus is on hot gas particulate removal and desulfurization technologies that match the temperatures and pressures of the gasifier, cleanup system, and power generator. The purpose of this poster is to present the program objectives and results of the work conducted in cooperation with industrial users and vendors to meet the vision for IGCC of reducing the capital cost per kilowatt to $1050 and increasing the plant efficiency to 52% by the year 2010.

  17. Hot gas in Mach cones around Virgo Cluster spiral galaxies

    OpenAIRE

    Wezgowiec, M.; Vollmer, B.; Ehle, M.; Dettmar, R. -J.; Bomans, D. J.; Chyzy, K. T.; Urbanik, M.; Soida, M.

    2011-01-01

    The detailed comparison between observations and simulations of ram pressure stripped spiral galaxies in the Virgo cluster has led to a three dimensional view of the galaxy orbits within the hot intracluster medium. The 3D velocities and Mach numbers derived from simulations can be used to derive simple Mach cone geometries for Virgo spiral galaxies. We search for indications of hot gas within Mach cones in X-ray observations of selected Virgo Cluster spiral galaxies (NGC 4569, NGC 4388, and ...

  18. Ceramic filters for removal of particulates from hot gas streams

    Energy Technology Data Exchange (ETDEWEB)

    Goldsmith, R.L.

    1992-01-01

    The primary goal is to demonstrate the performance of a new ceramic filter in removing particulate matter from hot gas streams produced in advanced coal conversion processes. The specific objectives are threefold: (1) Development of full size ceramic filters suitable for hot gas filtration; (2) Demonstration of ceramic filters in long term (ca. 1000 hrs) field trials; and (3) Development of full-scale hot gas filter system designs and costs. To date, field tests of the ceramic filter for particulate removal have been conducted at seven sites on a variety of gas streams and under a variety of test conditions. In general, the following performance characteristics have been observed: 1. Filtration face velocity (equivalent to an air to cloth ratio'') for flue gas tests is comparable to that for pulse jet bags operating at the same pressure drop. In hot gas tests, flow-pressure drop characteristics have been observed to be comparable to those for other ceramic filters. 2. Complete regeneration by a simple backpulse technique is achieved; i.e., no increase in clean filter resistance over repetitive cycles is observed. 3. No plugging of the filter passageways by badly caking particulates is observed. 4. Essentially complete particulate removal, including submicron particulate matter, is achieved.

  19. Ceramic filters for removal of particulates from hot gas streams

    Energy Technology Data Exchange (ETDEWEB)

    Goldsmith, R.L.

    1992-11-01

    The primary goal is to demonstrate the performance of a new ceramic filter in removing particulate matter from hot gas streams produced in advanced coal conversion processes. The specific objectives are threefold: (1) Development of full size ceramic filters suitable for hot gas filtration; (2) Demonstration of ceramic filters in long term (ca. 1000 hrs) field trials; and (3) Development of full-scale hot gas filter system designs and costs. To date, field tests of the ceramic filter for particulate removal have been conducted at seven sites on a variety of gas streams and under a variety of test conditions. In general, the following performance characteristics have been observed: 1. Filtration face velocity (equivalent to an ``air to cloth ratio``) for flue gas tests is comparable to that for pulse jet bags operating at the same pressure drop. In hot gas tests, flow-pressure drop characteristics have been observed to be comparable to those for other ceramic filters. 2. Complete regeneration by a simple backpulse technique is achieved; i.e., no increase in clean filter resistance over repetitive cycles is observed. 3. No plugging of the filter passageways by badly caking particulates is observed. 4. Essentially complete particulate removal, including submicron particulate matter, is achieved.

  20. Hot gas in the large magellanic cloud

    Directory of Open Access Journals (Sweden)

    You Hua Chu

    2000-01-01

    Full Text Available Debido a su cercanía, su orientación casi de frente y la baja extinción externa e interna, la Nube Mayor de Magallanes (LMC es un laboratorio excelente para estudiar la estructura física del medio interestelar (ISM. Estudios del gas de la LMC en el óptico y en el radio han mostrado estructuras interestelares que van de unos cuantos parsecs hasta más de 1000 pc. Los mosaicos hechos con ROSAT en rayos-X muestran la abundancia del gas caliente a 106 K, el cual a veces está rodeado de grandes cascarones, pero el resto no parece estar asociado a ninguna estructura interestelar visible. Las observaciones de rayos-X han sido analizadas para determinar las condiciones físicas del gas caliente. Para determinar su origen, la distribución del gas caliente puede ser comparada con la del gas más frío y con la de las estrellas masivas. Observaciones UV de líneas de absorción de iones de alta ionización como C IV, N V y O VI, pueden ser usadas para estudiar las interfases del gas a 106 K con el gas más frío y para dar restricciones sobre la localización de ambos a lo largo de la línea de visión.

  1. Hot gas filtration: Investigations to remove gaseous pollutant components out of flue gas during hot gas filtration. Final report; HGR: Untersuchung zur Minimierung von gasfoermigen Schadstoffen aus Rauchgasen bei der Heissgasfiltration. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Christ, A.; Gross, R.; Renz, U.

    1998-07-01

    Power plants with gas and steam turbines in pressurized fluidized bed or pressurized gasification processes enable power generation of coal with high efficiency and little emissions. To run these plants the cleaning of the flue gas is necessary before entering the turbines under the conditions of high temperature and pressure. Ceramic filter elements are the most probable method for hot gas cleaning. A simultaneous reduction of gaseous pollutant components under these conditions could help to make the whole process more efficient. The aim of the project is to integrate the catalytic reduction of carbon monoxide, hydrocarbons and nitric oxides into the hot gas filtration with ceramic filter elements as a one step mecanism. The project is focused on: - the catalytic behaviour of ferruginous ashes of brown coal, - the effectiveness of calcinated aluminates as a catalyst to remove uncombusted hydrocarbons in a hot gas filtration unit, - numerical simulation of the combined removal of particles and gaseous pollutant components out of the flue gas. (orig.) [Deutsch] Gas- und Dampfturbinen-Kraftwerke mit Druckwirbelschicht- oder mit Druckvergasungsverfahren ermoeglichen die Verstromung von Kohle mit hohem Wirkungsgrad und niedrigen Emissionen. Eine Voraussetzung fuer den Betrieb dieser Anlagen ist die Entstaubung der Rauchgase bei hohen Temperaturen und Druecken. Abreinigungsfilter mit keramischen Elementen werden dazu eingesetzt. Eine Reduzierung gasfoermiger Schadstoffe unter den gleichen Bedingungen koennte die Rauchgaswaesche ersetzen. Ziel des Gesamtvorhabens ist es, die Integration von Heissgasfiltration und katalytischem Abbau der Schadstoffe Kohlenmonoxid, Kohlenwasserstoffe und Stickoxide in einem Verfahrensschritt zu untersuchen. Die Arbeitsschwerpunkte dieses Teilvorhabens betreffen - die katalytische Wirkung eisenhaltiger Braunkohlenaschen, - die Wirksamkeit des Calciumaluminats als Katalysator des Abbaus unverbrannter Kohlenwasserstoffe im Heissgasfilter

  2. Low temperature catalytic combustion of natural gas - hydrogen - air mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Newson, E.; Roth, F. von; Hottinger, P.; Truong, T.B. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The low temperature catalytic combustion of natural gas - air mixtures would allow the development of no-NO{sub x} burners for heating and power applications. Using commercially available catalysts, the room temperature ignition of methane-propane-air mixtures has been shown in laboratory reactors with combustion efficiencies over 95% and maximum temperatures less than 700{sup o}C. After a 500 hour stability test, severe deactivation of both methane and propane oxidation functions was observed. In cooperation with industrial partners, scaleup to 3 kW is being investigated together with startup dynamics and catalyst stability. (author) 3 figs., 3 refs.

  3. The Hot Gas Halos of Galaxies in Groups

    CERN Document Server

    Jeltema, Tesla E; Mulchaey, John S

    2008-01-01

    We use Chandra observations of 13 nearby groups of galaxies to investigate the hot gas content of their member galaxies. We find that a large fraction of near-IR bright, early-type galaxies in groups have extended X-ray emission, indicating that they retain significant hot gas halos even in these dense environments. In particular, we detect hot gas halos in ~80% of L_K > L_star galaxies. We do not find a significant difference in the L_K-L_X relation for detected group and cluster early-type galaxies. However, we detect X-ray emission from a significantly higher fraction of galaxies brighter than L_star in groups compared to clusters, indicating that a larger fraction of galaxies in clusters experience significant stripping of their hot gas. In addition, group and cluster galaxies appear to be X-ray faint compared to field galaxies, though a Chandra based field sample is needed to confirm this result. The near-IR bright late-types galaxies in clusters and groups appear to follow the L_K-L_X relation for early...

  4. Viscous Coefficients of a Hot Pion Gas

    Directory of Open Access Journals (Sweden)

    Sourav Sarkar

    2013-01-01

    Full Text Available The steps essentially involved in the evaluation of transport coefficients in linear response theory using Kubo formulas are to relate the defining retarded correlation function to the corresponding time-ordered one and to evaluate the latter in the conventional perturbation expansion. Here we evaluate the viscosities of a pion gas carrying out both the steps in the real-time formulation. We also obtain the viscous coefficients by solving the relativistic transport equation in the Chapman-Enskog approximation to leading order. An in-medium π π cross-section is used in which spectral modifications are introduced in the propagator of the exchanged ρ .

  5. The hot gas content of fossil galaxy clusters

    CERN Document Server

    Pratt, G W; Arnaud, M; van der Burg, R F J

    2016-01-01

    We investigate the properties of the hot gas in four fossil galaxy systems detected at high significance in the Planck Sunyaev-Zeldovich (SZ) survey. XMM-Newton observations reveal overall temperatures of kT ~ 5-6 keV and yield hydrostatic masses M500,HE > 3.5 x 10e14 Msun, confirming their nature as bona fide massive clusters. We measure the thermodynamic properties of the hot gas in X-rays (out to beyond R500 in three cases) and derive their individual pressure profiles out to R ~ 2.5 R500 with the SZ data. We combine the X-ray and SZ data to measure hydrostatic mass profiles and to examine the hot gas content and its radial distribution. The average Navarro-Frenk-White (NFW) concentration parameter, c500 = 3.2 +/- 0.4, is the same as that of relaxed `normal' clusters. The gas mass fraction profiles exhibit striking variation in the inner regions, but converge to approximately the cosmic baryon fraction (corrected for depletion) at R500. Beyond R500 the gas mass fraction profiles again diverge, which we int...

  6. Mechanical Properties of Candidate Materials for Hot Gas Duct of VHTR

    International Nuclear Information System (INIS)

    Hot gas duct of VHTR is operated at 950 .deg.. Ni based superalloys, such as Hastelloy XR, Alloy 617, Haynes 230, for hot gas duct have been candidate material because of good strength and corrosion properties at high temperature. Mechanical properties of these alloys are tested at high temperature to apply to hot gas duct of VHTR

  7. Assessment of coal gasification/hot gas cleanup based advanced gas turbine systems

    Energy Technology Data Exchange (ETDEWEB)

    1990-12-01

    The major objectives of the joint SCS/DOE study of air-blown gasification power plants with hot gas cleanup are to: (1) Evaluate various power plant configurations to determine if an air-blown gasification-based power plant with hot gas cleanup can compete against pulverized coal with flue gas desulfurization for baseload expansion at Georgia Power Company's Plant Wansley; (2) determine if air-blown gasification with hot gas cleanup is more cost effective than oxygen-blown IGCC with cold gas cleanup; (3) perform Second-Law/Thermoeconomic Analysis of air-blown IGCC with hot gas cleanup and oxygen-blown IGCC with cold gas cleanup; (4) compare cost, performance, and reliability of IGCC based on industrial gas turbines and ISTIG power island configurations based on aeroderivative gas turbines; (5) compare cost, performance, and reliability of large (400 MW) and small (100 to 200 MW) gasification power plants; and (6) compare cost, performance, and reliability of air-blown gasification power plants using fluidized-bed gasifiers to air-blown IGCC using transport gasification and pressurized combustion.

  8. Hot section components life usage analyses for industrial gas turbines

    OpenAIRE

    Saturday, Egbigenibo Genuine

    2015-01-01

    Industrial gas turbines generally operate at a bit stable power levels and the hot section critical components, especially high pressure turbine blades are prone to failure due to creep. In some cases, plants are frequently shut down, thus, in addition to creep low cycle fatigue failure equally sets in. Avoiding failure calls for proper monitoring of how the lives of these components are being consumed. Efforts are thus being made to estimate the life of the critical components...

  9. Tidd hot gas clean up program. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-10-01

    This Final Report on the Tidd Hot Gas Clean Up Program covers the period from initial Proof-of-Concept testing in August, 1990, through final equipment inspections in May, 1995. The Tidd Hot Gas Clean Up (HGCU) system was installed in the Tidd Pressurized Fluidized Bed Combustion (PFBC) Demonstration Plant, which is the first utility-scale PFBC plant in the United States. Detailed design work on the project began in July, 1990, and site construction began in December, 1991. Initial operation of the system occurred in May, 1992, and the hot gas filter was commissioned in October, 1992. The test program ended in March, 1995, when the Tidd Plant was shut down following its four-year test program. Section 1.0 of this report is an executive summary of the project covering the project background, system description, test results and conclusions. Section 2.0 is an introduction covering the program objectives and schedule. Section 3.0 provides detailed descriptions of the system and its major components. Section 4.0 provides detailed results of all testing including observations and posttest inspection results. Sections 5.0 and 6.0 list the program conclusions and recommendations, respectively. Appendix I is a report prepared by Southern Research Institute on the properties of Tidd PFBC ash sampled during the test program. Appendix II is a report prepared by Westinghouse STC on the performance of candle filter fail-safe regenerator devices.

  10. Production of light oil by injection of hot inert gas

    Science.gov (United States)

    Ruidas, Bidhan C.; Ganguly, Somenath

    2016-05-01

    Hot inert gas, when injected into an oil reservoir is capable of generating a vaporization-condensation drive and as a consequence, a preferential movement of the lighter components to the production well. This form of displacement is an important unit mechanism in hot flue-gas injection, or in thermal recovery from a watered-out oil reservoir. This article presents the movement of heat front vis-à-vis the changes in the saturation profile, and the gas-phase composition. The plateau in the temperature profile due to the exchange of latent heat, and the formation of water bank at the downstream are elaborated. The broadening of the vaporization-condensation zone with continued progression is discussed. The effect of inert gas temperature on the cumulative production of oil is reviewed. The results provide insight to the vaporization-condensation drive as a stand-alone mechanism. The paper underscores the relative importance of this mechanism, when operated in tandem with other processes in improved oil recovery and CO2 sequestration.

  11. $X(3872)$ production and absorption in a hot hadron gas

    CERN Document Server

    Abreu, L M; Torres, A Martinez; Navarra, F S; Nielsen, M

    2016-01-01

    We calculate the time evolution of the $X(3872)$ abundance in the hot hadron gas produced in the late stage of heavy ion collisions. We use effective field Lagrangians to obtain the production and dissociation cross sections of $X(3872)$. In this evaluation we include diagrams involving the anomalous couplings $\\pi D^*\\bar{D}^*$ and $X \\bar{D}^{\\ast} D^{\\ast}$ and also the couplings of the $X(3872)$ with charged $D$ and $D^*$ mesons. With these new terms the $X(3872)$ interaction cross sections are much larger than those found in previous works. Using these cross sections as input in rate equations, we conclude that during the expansion and cooling of the hadronic gas, the number of $X(3872)$, originally produced at the end of the mixed QGP/hadron gas phase, is reduced by a factor of 4.

  12. X(3872) production and absorption in a hot hadron gas

    Science.gov (United States)

    Abreu, L. M.; Khemchandani, K. P.; Torres, A. Martínez; Navarra, F. S.; Nielsen, M.

    2016-10-01

    We calculate the time evolution of the X (3872) abundance in the hot hadron gas produced in the late stage of heavy ion collisions. We use effective field Lagrangians to obtain the production and dissociation cross sections of X (3872). In this evaluation we include diagrams involving the anomalous couplings πD*Dbar* and XDbar*D* and also the couplings of the X (3872) with charged D and D* mesons. With these new terms the X (3872) interaction cross sections are much larger than those found in previous works. Using these cross sections as input in rate equations, we conclude that during the expansion and cooling of the hadronic gas, the number of X (3872), originally produced at the end of the mixed QGP/hadron gas phase, is reduced by a factor of 4.

  13. Apparatus for hot-gas desulfurization of fuel gases

    Science.gov (United States)

    Bissett, Larry A.

    1992-01-01

    An apparatus for removing sulfur values from a hot fuel gas stream in a fdized bed contactor containing particulate sorbent material by employing a riser tube regeneration arrangement. Sulfur-laden sorbent is continuously removed from the fluidized bed through a stand pipe to the riser tube and is rapidly regenerated in the riser tube during transport of the sorbent therethrough by employing an oxygen-containing sorbent regenerating gas stream. The riser tube extends from a location below the fluidized bed to an elevation above the fluidized bed where a gas-solid separating mechanism is utilized to separate the regenerated particulate sorbent from the regeneration gases and reaction gases so that the regenerated sorbent can be returned to the fluidized bed for reuse.

  14. Rotor disk cooling and rim sealing to prevent hot gas ingestion. Rotor reikyaku to hot gas no seal

    Energy Technology Data Exchange (ETDEWEB)

    Hamabe, K. (Kawasaki Heavy Industries, Ltd., Tokyo (Japan))

    1993-03-01

    In designing a high-temperature gas turbine disc, it is necessary to know pressure distribution around a disc, which correlates with flows inside and outside the disc. With design conditions becoming very stringent for efficiency improvement as a background, this paper describes latest trends in technologies on heat transfer around a disc and hot gas sealing while introducing reports on various studies. Generally speaking, fundamental researches on rotors without mainstreams have conventionally been carried out mainly in Europe and the U.S.A. Researches have become active recently on entrainment of mainstream gas where there is a mainstream that renders practical problems. The number of research papers is increasing sharply that relate to rotor shapes closer to those used in practical turbines incorporating moving and static blades, and high rotation Reynolds numbers. Further, studies using numerical analysis are on the increase, and rotor cooling studies are advancing remarkably in recent years. 36 refs., 10 figs.

  15. Sealing system for piston rod of hot gas engine

    Energy Technology Data Exchange (ETDEWEB)

    Lundholm, S.G.; Ringqvist, S.A.

    1980-11-25

    An improvement to a sealing system for restricting fluid flow around a piston rod between a piston cylinder and crankshaft space in a hot gas engine where a seal element is secured around the piston rod in an intermediate chamber, the improvement including a link in the crankshaft space connecting, and permitting relative radial motion between, the piston rod and the crosshead and an o-ring having a diameter substantially greater than that of the piston rod and being secured between a lower ring securing the seal element in place around the piston rod and a wall of the intermediate chamber for frictionally restricting radial movement of the lower ring.

  16. Bulk and shear viscosities of hot and dense hadron gas

    CERN Document Server

    Kadam, Guru Prakash

    2014-01-01

    We estimate bulk and shear viscosity at finite temperature and baryon densities of hadronic matter within hadron resonance gas model. For bulk viscosity we use low energy theorems of QCD for the energy momentum tensor correlators. For shear viscosity coefficient, we estimate the same using molecular kinetic theory to relate the shear viscosity coefficient to average momentum of the hadrons in the hot and dense hadron gas. The bulk viscosity to entropy ratio increases with chemical potential and is related to the reduction of velocity of sound at nonzero chemical potential. The shear viscosity to entropy ratio on the other hand, shows a nontrivial behavior with the ratio decreasing with chemical potential for small temperatures but increasing with chemical potential at high temperatures and is related to decrease of entropy density with chemical potential at high temperature due to finite volume of the hadrons.

  17. Hot-gas filtration for pressurized fluidized-bed combustion

    Energy Technology Data Exchange (ETDEWEB)

    Chang, R.; Kuby, W.

    1984-03-01

    This topical report discusses the status of the work, conducted under EPRI contract 1336-4, on the evaluation and development of ceramic filter hot gas cleanup technology for pressurized fluidized bed combustion. This topical report represents the status of the work through September 1983. The goal of the effort is to achieve 6000 h of operation on a 13-filter durability test rig. The work includes two parallel tasks. The first is construction of a durability test facility, operation of the facility with an initial candidate filter media installed, and assessment of results. The second task includes a literature survey to identify state-of-the-art ceramic fibers suitable for high-temperature gas filtration applications and filter testing in a single-filter test facility to assess the performance of promising new filter media. The best candidate will be chosen for further evaluation in the durability facility.

  18. Catalytic partial oxidation of methane to synthesis gas over ZRO2-based defective oxides

    NARCIS (Netherlands)

    Zhu, Jianjun

    2005-01-01

    the work presented in this thesis provides both fundamental scientific knowledge as well as a new technical dual-bed concept for synthesis gas production via catalytic partial oxidation of methane over defective ZrO2-based oxides.

  19. Design and Experimentation with Sandwich Microstructure for Catalytic Combustion-Type Gas Sensors

    OpenAIRE

    Jun-Tao Gu; Yong-De Zhang; Jin-Gang Jiang

    2014-01-01

    The traditional handmade catalytic combustion gas sensor has some problems such as a pairing difficulty, poor consistency, high power consumption, and not being interchangeable. To address these issues, integrated double catalytic combustion of alcohol gas sensor was designed and manufactured using silicon micro-electro-mechanical systems (MEMS) technology. The temperature field of the sensor is analyzed using the ANSYS finite element analysis method. In this work, the silicon oxide-PECVD-oxi...

  20. Development of advanced hot-gas desulfurization processes

    Energy Technology Data Exchange (ETDEWEB)

    Jothimurugesan, K.

    1999-10-14

    Advanced integrated gasification combined cycle (IGCC) power plants nearing completion, such as Sierra-Pacific, employ a circulating fluidized-bed (transport) reactor hot-gas desulfurization (HGD) process that uses 70-180 {micro}m average particle size (aps) zinc-based mixed-metal oxide sorbent for removing H{sub 2}S from coal gas down to less than 20 ppmv. The sorbent undergoes cycles of absorption (sulfidation) and air regeneration. The key barrier issues associated with a fluidized-bed HGD process are chemical degradation, physical attrition, high regeneration light-off (initiation) temperature, and high cost of the sorbent. Another inherent complication in all air-regeneration-based HGD processes is the disposal of the problematic dilute SO{sub 2} containing regeneration tail-gas. Direct Sulfur Recovery Process (DSRP), a leading first generation technology, efficiently reduces this SO{sub 2} to desirable elemental sulfur, but requires the use of 1-3 % of the coal gas, thus resulting in an energy penalty to the plant. Advanced second-generation processes are under development that can reduce this energy penalty by modifying the sorbent so that it could be directly regenerated to elemental sulfur. The objective of this research is to support the near and long term DOE efforts to commercialize the IGCC-HGD process technology. Specifically we aim to develop: optimized low-cost sorbent materials with 70-80 {micro}m average aps meeting all Sierra specs; attrition resistant sorbents with 170 {micro}m aps that allow greater flexibility in the choice of the type of fluidized-bed reactor e.g. they allow increased throughput in a bubbling-bed reactor; and modified fluidizable sorbent materials that can be regenerated to produce elemental sulfur directly with minimal or no use of coal gas The effort during the reporting period has been devoted to development of an advanced hot-gas process that can eliminate the problematic SO{sub 2} tail gas and yield elemental sulfur

  1. Catalytic pleat filter bags for combined particulate separation and nitrogen oxides removal from flue gas streams

    International Nuclear Information System (INIS)

    The development of a high temperature catalytically active pleated filter bag with hybrid filter equipment for the combined removal of particles and nitrogen oxides from flue gas streams is presented. A special catalyst load in stainless steel mesh cartridge with a high temperature pleated filter bag followed by optimized catalytic activation was developed to reach the required nitrogen oxides levels and to maintain the higher collection efficiencies. The catalytic properties of the developed high temperature filter bags with hybrid filter equipment were studied and demonstrated in a pilot scale test rig and a demonstration plant using commercial scale of high temperature catalytic pleated filter bags. The performance of the catalytic pleated filter bags were tested under different operating conditions, such as filtration velocity and operating temperature. Moreover, the cleaning efficiency and residual pressure drop of the catalyst loaded cartridges in pleated filter bags were tested. As result of theses studies, the optimum operating conditions for the catalytic pleated filter bags are determined. (author)

  2. Integrated hot fuel gas cleaning for advanced gasification combined cycle process

    Energy Technology Data Exchange (ETDEWEB)

    Nieminen, M.; Kangasmaa, K.; Laatikainen, J.; Staahlberg, P.; Kurkela, E. [VTT Energy, Espoo (Finland). Gasification and Advanced Combustion

    1996-12-01

    The fate of halogens in pressurised fluidized-bed gasification and hot gas filtration is determined. Potential halogen removal sorbents, suitable for integrated hot gas cleaning, are screened and some selected sorbents are tested in bench scale. Finally, halogen removal results are verified using the PDU-scale pressurised fluidized-bed gasification and integrated hot gas cleaning facilities of VTT. The project is part of the JOULE II Extension programme of the European Union. (author)

  3. Progress in catalytic membrane reactors for removing sulfur from natural gas

    Institute of Scientific and Technical Information of China (English)

    TAO Chang-yuan; LIU Zuo-hua; DU Jun; LIU Ren-long

    2007-01-01

    Increasingly high requirement driven by environmental concern leads to more rigorous standards for sulfur dosage in fuel. Natural gas desulfurization is an important unit for industrial natural gas process. Catalytic membrane reactor for sulfur compounds removal is a newly emerged and integrated membrane technology. We reviewed the current progress for desulfurization of natural gas with membrane process, and predicted that the process combined with catalytic membrane reactor and microwave irradiation for desulfurization of natural gas might be an integrated and promising unit for large scale desulfurization with high efficiency.

  4. Evidence of catalytic production of hot hydrogen in rf generated hydrogen/argon plasmas

    CERN Document Server

    Phillips, J; Akhtar, K; Dhandapani, B; Mills, R; Phillips, Jonathan; Chen, Chun-Ku; Akhtar, Kamran; Dhandapani, Bala; Mills, Randell

    2005-01-01

    In this paper the selective broadening of the atomic hydrogen lines in pure H2 and Ar/H2 mixtures in a large 'GEC' cell (36 cm length_ 14 cm ID) was mapped as a function of position, H2/Ar ratio, time, power, and pressure. Several observations regarding the selective line broadening were particularly notable as they are unanticipated on the basis of earlier models. First, the anomalous broadening of the Balmer lines was found to exist throughout the plasma, and not just in the region between the electrodes. Second, the broadening was consistently a complex function of the operating parameters particularly gas composition (highest in pure H2), position, power, time and pressure. Clearly not anticipated by earlier models were the findings that under some conditions the highest concentration of 'hot' (>10 eV) hydrogen was found at the entry end, and not in the high field region between the electrodes and that in other conditions, the hottest H was at the (exit) pump (also grounded electrode) end. Third, excitati...

  5. BENCH-SCALE DEMONSTRATION OF HOT-GAS DESULFURIZATION TECHNOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-05-01

    The Direct Sulfur Recovery Process (DSRP) is a one- or two-stage catalytic reduction process for efficiently converting to elemental sulfur up to 98 percent or more of the sulfur dioxide (SO{sub 2}) contained in the regeneration offgas streams produced in advanced integrated gasification combined cycle (IGCC) power systems. The DSRP reacts the regeneration offgas with a small slipstream of coal gas to effect the desired reduction. In this project the DSRP was demonstrated with actual coal gas (as opposed to the simulated laboratory mixtures used in previous studies) in a 75-mm, 1-L size fixed-bed reactor. Integrated with this testing, a US Department of Energy/Research Triangle Institute (DOE/RTI) patented zinc titanate-based fluidizable sorbent formulation was tested in a 75-mm (3-in.) diameter fluidized-bed reactor, and the regeneration offgas from that test was treated with the bench-unit DSRP. The testing was conducted at the DOE Federal Energy Technology Center (FETC)-Morgantown in conjunction with test campaigns of the pilot-scale gasifier there. The test apparatus was housed in a mobile laboratory built in a specially equipped office trailer that facilitated moving the equipment from RTI in North Carolina to the West Virginia test site. A long duration test of the DSRP using actual coal gas and simulated regeneration offgas showed no degradation in efficiency of conversion to elemental sulfur after 160 h of catalyst exposure. An additional exposure (200 h) of that same catalyst charge at the General Electric pilot gasifier showed only a small decline in performance. That problem is believed to have been caused by tar and soot deposits on the catalyst, which were caused by the high tar content of the atypical fixed-bed gasifier gas. A six-fold larger, single-stage skid-mounted DSRP apparatus was fabricated for additional, larger-scale slipstream testing.

  6. The Enrichment History of Hot Gas in Poor Galaxy Groups

    CERN Document Server

    Davis, D S; Mushotzky, R F; Davis, David S.; Mulchaey, John S.; Mushotzky, Richard F.

    1999-01-01

    We have analyzed the ASCA SIS and GIS data for seventeen groups and determined the average temperature and abundance of the hot x-ray emitting gas. For groups with gas temperatures less than 1.5 keV we find that the abundance is correlated with the gas temperature and luminosity. We have also determined the abundance of the alpha-elements and iron independently for those groups with sufficient counts. We find that for the cool groups (i.e. kT <1.5 keV) the ratio of alpha-elements to iron is ~1, about half that seen in clusters. Spectral fits with the S, Si and Fe abundances allowed to vary separately suggest the S/Fe ratio is similar to that seen in clusters while the Si/Fe ratio in groups is half the value determined for richer systems. The mass of metals per unit blue luminosity drops rapidly in groups as the temperature drops. There are two possible explanations for this decrease. One is that the star formation in groups is very different from that in rich clusters. The other explanation is that groups ...

  7. AGN-stimulated Cooling of Hot Gas in Elliptical Galaxies

    CERN Document Server

    Valentini, Milena

    2015-01-01

    We study the impact of relatively weak AGN feedback on the interstellar medium of intermediate and massive elliptical galaxies. We find that the AGN activity, while globally heating the ISM, naturally stimulates some degree of hot gas cooling on scales of several kpc. This process generates the persistent presence of a cold ISM phase, with mass ranging between 10$^4$ and $\\gtrsim$ 5 $\\times$ 10$^7$ M$_\\odot$, where the latter value is appropriate for group centered, massive galaxies. Widespread cooling occurs where the ratio of cooling to free-fall time before the activation of the AGN feedback satisfies $t_{cool}/t_{ff} \\lesssim 70$, that is we find a less restrictive threshold than commonly quoted in the literature. This process helps explaining the body of observations of cold gas (both ionized and neutral/molecular) in Ellipticals and, perhaps, the residual star formation detected in many early-type galaxies. The amount and distribution of the off-center cold gas vary irregularly with time. The cold ISM v...

  8. DEVELOPMENT OF ADVANCED HOT-GAS DESULFURIZATION PROCESSES

    Energy Technology Data Exchange (ETDEWEB)

    K. Jothimurugesan; Santosh K. Gangwal

    2000-12-01

    The techniques employed in this project have successfully demonstrated the feasibility of preparing sorbents that achieve greater than 99% H{sub 2}S removal at temperatures 480 C and that retain their activity over 50 cycles. Fundamental understanding of phenomena leading to chemical deactivation and high regeneration light-off temperature has enabled us to successfully prepare and scale up a FHR-32 sorbent that showed no loss in reactivity and capacity over 50 cycles. This sorbent removed H{sub 2}S below 80 ppmv and lighted-off nicely at 480 C during regeneration. Overall the test is a success with potential for an optimized FHR-32 to be a candidate for Sierra-Pacific. An advanced attrition resistant hot-gas desulfurization sorbent that can eliminate the problematic SO{sub 2} tail gas and yield elemental sulfur directly has been developed. Attrition resistant Zn-Fe sorbent (AHI-2) formulations have been prepared that can remove H{sub 2}S to below 20 ppmv from coal gas and can be regenerated using SO{sub 2} to produce elemental sulfur.

  9. Hot gas stream application in micro-bonding technique

    Science.gov (United States)

    Andrijasevic, Daniela; Giouroudi, Ioanna; Smetana, Walter; Boehm, Stefan; Brenner, Werner

    2006-01-01

    This paper presents a new concept for bonding micro-parts with dimensions in the range of 50 μm to 300 μm. Two different kinds of adhesives - polyurethane adhesive foil and hot melt glue - were applied to a basic substrate by different techniques. The focused and concentrated hot gas stream softened glue which had been applied in a solid state. Micro-parts were then embossed in the softened glue, or covered and shielded by it. In this way, a rigid and compact bond was obtained after cooling. For the positioning of micro-parts (optical fibers), it has been necessary to manufacture adequate V-grooves. Finite element analyses using the ANSYS TM program package were performed in order to evaluate parameters which govern the heat transfer to the adhesive and substrate respectively. Experimental results are in good agreement with results obtained by the numerical simulations. The advantages of this new approach are small system size, low capital costs, simple usage, applicability to many material combinations, easy integration into existing production lines, etc.

  10. Hot-Wire Chemical Vapor Deposition Of Polycrystalline Silicon : From Gas Molecule To Solar Cell

    Science.gov (United States)

    van Veenendaal, P. A. T. T.

    2002-10-01

    Although the effort to investigate the use of renewable energy sources, such as wind and solar energy, has increased, their contribution to the total energy consumption remains insignificant. The conversion of solar energy into electricity through solar cells is one of the most promising techniques, but the use of these cells is limited by the high cost of electricity. The major contributions to these costs are the material and manufacturing costs. Over the past decades, the development of silicon based thin film solar cells has received much attention, because the fabrication costs are low. A promising material for use in thin film solar cells is polycrystalline silicon (poly-Si:H). A relatively new technique to deposit poly-Si:H is Hot-Wire Chemical Vapor Deposition (Hot-Wire CVD), in which the reactant gases are catalytically decomposed at the surface of a hot filament, mainly tungsten and tantalum. The main advantages of Hot-Wire CVD over PE-CVD are absence of ion bombardment, high deposition rate, low equipment cost and high gas utilization. This thesis deals with the full spectrum of deposition, characterization and application of poly-Si:H thin films, i.e. from gas molecule to solar cell. Studies on the decomposition of silane on the filament showed that the process is catalytic of nature and that silane is decomposed into Si and 4H. The dominant gas phase reaction is the reaction of Si and H with silane, resulting in SiH3, Si2H6, Si3H6 and H2SiSiH2. The film growth precursors are Si, SiH3 and Si2H4. Also, XPS results on used tantalum and tungsten filaments are discussed. The position dependent measurements show larger silicon contents at the ends of the tungsten filament, as compared to the middle, due to a lower filament temperature. This effect is insignificant for a tantalum filament. Deposition time dependent measurements show an increase in silicon content of the tungsten filament with time, while the silicon content on the tantalum filament saturates

  11. Enrichment study of hot intra-cluster gas through X-ray spectroscopy

    NARCIS (Netherlands)

    Plaa, J. de

    2007-01-01

    Enrichment study of hot intra-cluster gas through X-ray spectroscopy Clouds of hot X-ray emitting gas associated with clusters of galaxies are the biggest aggregates of baryons that we know, except for the cosmic web. A typical cloud contains the nuclear-fusion products of billions of supernovae. Th

  12. Qualification of Ni-base superalloys for hot gas duct of VHTR

    International Nuclear Information System (INIS)

    Hot gad duct of VHTR is operated at 950 .deg. C. Ni based superalloys for hot gas duct have been candidate in other country such as Hastelloy X for Japan, Alloy 617 for USA, and Haynes 230 for France because of good strength and corrosion properties at high temperature. Mechanical properties of these alloys are tested and compared with ASME design Code to apply to hot gas duct of VHTR

  13. Development and test of a new catalytic converter for natural gas fuelled engine

    Indian Academy of Sciences (India)

    M A Kalam; H H Masjuki; M Redzuan; T M I Mahlia; M A Fuad; M Mohibah; K H Halim; A Ishak; M Khair; A Shahrir; A Yusoff

    2009-06-01

    This paper presents characteristics of a new catalytic converter (catco) to be used for natural gas fuelled engine. The catco were developed based on catalyst materials consisting of metal oxides such as titanium dioxide (TiO2) and cobalt oxide (CoO) with wire mesh substrate. Both of the catalyst materials (such as TiO2 and CoO) are inexpensive in comparison with conventional catalysts (noble metals) such as palladium or platinum. In addition, the noble metals such as platinum group metals are now identified as human health risk due to their rapid emissions in the environment from various resources like conventional catalytic converter, jewelers and other medical usages. It can be mentioned that the TiO2/CoO based catalytic converter and a new natural gas engine such as compressed natural gas (CNG) direct injection (DI) engine were developed under a research collaboration program. The original engine manufacture catalytic conveter (OEM catco) was tested for comparison purposes. The OEM catco was based on noble metal catalyst with honeycomb ceramic substrate. It is experimentally found that the conversion efficiencies of TiO2/CoO based catalytic converter are 93%, 89% and 82% for NOx, CO and HC emissions respectively. It is calculated that the TiO2/CoO based catalytic converter reduces 24%, 41% and 40% higher NOx, CO and HC emissions in comparison to OEM catco respectively. The objective of this paper is to develop a low-cost three way catalytic converter to be used with the newly developed CNG-DI engine. Detailed review on catalytic converter, low-cost catalytic converter development characteristics and CNGDI engine test results have been presented with discussions.

  14. Development of advanced hot-gas desulfurization processes

    Energy Technology Data Exchange (ETDEWEB)

    Jothimurugesan, K.

    1999-04-26

    Advanced integrated gasification combined cycle (IGCC) power plants nearing completion, such as Sierra-Pacific, employ a circulating fluidized-bed (transport) reactor hot-gas desulfurization (HGD) process that uses 70-180 {micro}m average particle size (aps) zinc-based mixed-metal oxide sorbent for removing H{sub 2}S from coal gas down to less than 20 ppmv. The sorbent undergoes cycles of absorption (sulfidation) and air regeneration. The key barrier issues associated with a fluidized-bed HGD process are chemical degradation, physical attrition, high regeneration light-off (initiation) temperature, and high cost of the sorbent. Another inherent complication in all air-regeneration-based HGD processes is the disposal of the problematic dilute SO{sub 2} containing regeneration tail-gas. Direct Sulfur Recovery Process (DSRP), a leading first generation technology, efficiently reduces this SO{sub 2} to desirable elemental sulfur, but requires the use of 1-3% of the coal gas, thus resulting in an energy penalty to the plant. Advanced second-generation processes are under development that can reduce this energy penalty by modifying the sorbent so that it could be directly regenerated to elemental sulfur. The objective of this research is to support the near and long term DOE efforts to commercialize the IGCC-HGD process technology. Specifically we aim to develop: optimized low-cost sorbent materials with 70-80 {micro}m average aps meeting all Sierra specs; attrition resistant sorbents with 170 {micro}m aps that allow greater flexibility in the choice of the type of fluidized-bed reactor e.g. they allow increased throughput in a bubbling-bed reactor; and modified fluidizable sorbent materials that can be regenerated to produce elemental sulfur directly with minimal or no use of coal gas. The effort during the reporting period has been devoted to development of optimized low-cost zinc-oxide-based sorbents for Sierra-Pacific. The sorbent surface were modified to prevent

  15. Bulk and shear viscosities of hot and dense hadron gas

    International Nuclear Information System (INIS)

    We estimate the bulk and the shear viscosity at finite temperature and baryon densities of hadronic matter within a hadron resonance gas model which includes a Hagedorn spectrum. The parameters of the Hagedorn spectrum are adjusted to fit recent lattice QCD simulations at finite chemical potential. For the estimation of the bulk viscosity we use low energy theorems of QCD for the energy momentum tensor correlators. For the shear viscosity coefficient, we estimate the same using molecular kinetic theory to relate the shear viscosity coefficient to average momentum of the hadrons in the hot and dense hadron gas. The bulk viscosity to entropy ratio increases with chemical potential and is related to the reduction of velocity of sound at nonzero chemical potential. The shear viscosity to entropy ratio on the other hand, shows a nontrivial behavior with the ratio decreasing with chemical potential for small temperatures but increasing with chemical potential at high temperatures and is related to decrease of entropy density with chemical potential at high temperature due to finite volume of the hadrons

  16. KINETICS OF HOT-GAS DESULFURIZATION SORBENTS FOR TRANSPORT REACTORS

    Energy Technology Data Exchange (ETDEWEB)

    K.C. Kwon

    2003-02-01

    Hot-gas desulfurization for the integrated gasification combined cycle (IGCC) process has been investigated by many researchers to remove effectively hydrogen sulfide with various metal oxide sorbents at elevated temperatures. Various metal oxide sorbents are formulated with metal oxides such as Fe, Co, Zn, and Ti. Initial reaction kinetics of formulated sorbents with hydrogen sulfide is studied in the presence of various amounts of moisture and hydrogen at various reaction temperatures. The objectives of this research are to study initial reaction kinetics for a sorbent-hydrogen sulfide heterogeneous reaction system, to investigate effects of concentrations of hydrogen sulfide, hydrogen, and moisture on dynamic absorption of H{sub 2}S into sorbents, and to evaluate effects of temperature and sorbent amounts on dynamic absorption of H{sub 2}S into sorbents. Experimental data on initial reaction kinetics of hydrogen sulfide with metal oxide sorbents were obtained with a 0.83-cm{sup 3} differential reactor. The reactivity of EX-SO3 was examined in this report. This sorbent was obtained from the Research Triangle Institute (RTI). The sorbent in the form of 110 {micro}m particles are reacted with 18000-ppm hydrogen sulfide at 350-550 C. The range of space time of reaction gas mixtures is 0.069-0.088 s. The range of reaction duration is 4-180 s.

  17. KINETICS OF HOT-GAS DESULFURIZATION SORBENTS FOR TRANSPORT REACTORS

    Energy Technology Data Exchange (ETDEWEB)

    K.C. Kwon

    2002-01-01

    Hot-gas desulfurization for the integrated gasification combined cycle (IGCC) process has been investigated by many researchers to remove effectively hydrogen sulfide with various metal oxide sorbents at elevated temperatures. Various metal oxide sorbents are formulated with metal oxides such as Fe, Co, Zn, and Ti. Initial reaction kinetics of formulated sorbents with hydrogen sulfide is studied in the presence of various amounts of moisture and hydrogen at various reaction temperatures. The objectives of this research are to study initial reaction kinetics for a sorbent-hydrogen sulfide heterogeneous reaction system, to investigate effects of concentrations of hydrogen sulfide, hydrogen, and moisture on dynamic absorption of H{sub 2}S into sorbents, and to evaluate effects of temperature and sorbent amounts on dynamic absorption of H{sub 2}S into sorbents. Experimental data on initial reaction kinetics of hydrogen sulfide with metal oxide sorbents were obtained with a 0.83-cm{sup 3} differential reactor. The reactivity of MCRH-67 was examined in this report. This sorbent was obtained from the Research Triangle Institute (RTI). The sorbent in the form of 130 mm particles are reacted with 18000-ppm hydrogen sulfide at 350-525 C. The range of space time of reaction gas mixtures is 0.069-0.088 s. The range of reaction duration is 4-180 s.

  18. Effects of Gas Velocity and Temperature on Nitric Oxide Conversion in Simulated Catalytic Converter

    OpenAIRE

    Sathaporn Chuepeng

    2012-01-01

    Problem statement: Gaseous emissions from gasoline engine such as carbon monoxide, unburned hydrocarbon and nitrogen oxides were usually reduced in three-way catalytic converter simultaneously around theoretical fuel and air combustion. Engine speed and load and other parameters were varied over a wide range of operating conditions, resulting in different exhaust gas composition and condition intake into catalytic converter. This work was studied the conversion of Nitric Oxide (NO) in exhaust...

  19. Process analysis of syngas production by non-catalytic POX of oven gas

    Institute of Scientific and Technical Information of China (English)

    Fuchen WANG; Xinwen ZHOU; Wenyuan GUO; Zhenghua DAI; Xin GONG; Haifeng LIU; Guangsuo YU; Zunhong YU

    2009-01-01

    A non-catalytic POX of oven gas is proposed to solve the problem of secondary pollution due to solid wastes produced from the great amount of organic sulfur contained in oven gas in the traditional catalytic partial oxidation (POX) process. A study of the measurement of flow field and a thermodynamic analysis of the process characteristics were conducted. Results show that there exist a jet-flow region, a recirculation-flow region, a tube-flow region, and three corresponding reaction zones in the non-catalytic POX reformer. The combustion of oven gas occurs mainly in the jet-flow region, while the reformation of oven gas occurs mainly in the other two regions. Soot would not be formed by CH4 cracking at above 1200℃. Since there are very little C2+ hydrocarbons in oven gas, the soot produced would be very tiny, even if they underwent cracking reaction. The integrated model for entrained bed gasification process was applied to simulate a non-catalytic POX reformer. It indicated that the proper oxygen-to-oven gas ratio is 0.22-0.28 at differ-ent pressures in the oven gas reformation process.

  20. Development of advanced hot-gas desulfurization processes

    Energy Technology Data Exchange (ETDEWEB)

    Jothimurugesan, K.

    2000-04-17

    Advanced integrated gasification combined cycle (IGCC) power plants nearing completion, such as Sierra-Pacific, employ a circulating fluidized-bed (transport) reactor hot-gas desulfurization (HGD) process that uses 70-180 {micro}m average particle size (aps) zinc-based mixed-metal oxide sorbent for removing H{sub 2}S from coal gas down to less than 20 ppmv. The sorbent undergoes cycles of absorption (sulfidation) and air regeneration. The key barrier issues associated with a fluidized-bed HGD process are chemical degradation, physical attrition, high regeneration light-off (initiation) temperature, and high cost of the sorbent. Another inherent complication in all air-regeneration-based HGD processes is the disposal of the problematic dilute SO{sub 2} containing regeneration tail-gas. Direct Sulfur Recovery Process (DSRP), a leading first generation technology, efficiently reduces this SO{sub 2} to desirable elemental sulfur, but requires the use of 1-3 % of the coal gas, thus resulting in an energy penalty to the plant. Advanced second-generation processes are under development that can reduce this energy penalty by modifying the sorbent so that it could be directly regenerated to elemental sulfur. The objective of this research is to support the near and long term DOE efforts to commercialize the IGCC-HGD process technology. Specifically we aim to develop: optimized low-cost sorbent materials with 70-80 {micro}m average aps meeting all Sierra specs; attrition resistant sorbents with 170 {micro}m aps that allow greater flexibility in the choice of the type of fluidized-bed reactor e.g. they allow increased throughput in a bubbling-bed reactor; and modified fluidizable sorbent materials that can be regenerated to produce elemental sulfur directly with minimal or no use of coal gas. The effort during the reporting period has been devoted to testing the FHR-32 sorbent. FHR-32 sorbent was tested for 50 cycles of sulfidation in a laboratory scale reactor.

  1. ENGINEERING A NEW MATERIAL FOR HOT GAS CLEANUP

    Energy Technology Data Exchange (ETDEWEB)

    T.D. Wheelock; L.K. Doraiswamy; K.P. Constant

    2003-09-01

    The overall purpose of this project was to develop a superior, regenerable, calcium-based sorbent for desulfurizing hot coal gas with the sorbent being in the form of small pellets made with a layered structure such that each pellet consists of a highly reactive lime core enclosed within a porous protective shell of strong but relatively inert material. The sorbent can be very useful for hot gas cleanup in advanced power generation systems where problems have been encountered with presently available materials. An economical method of preparing the desired material was demonstrated with a laboratory-scale revolving drum pelletizer. Core-in-shell pellets were produced by first pelletizing powdered limestone or other calcium-bearing material to make the pellet cores, and then the cores were coated with a mixture of powdered alumina and limestone to make the shells. The core-in-shell pellets were subsequently calcined at 1373 K (1100 C) to sinter the shell material and convert CaCO{sub 3} to CaO. The resulting product was shown to be highly reactive and a very good sorbent for H{sub 2}S at temperatures in the range of 1113 to 1193 K (840 to 920 C) which corresponds well with the outlet temperatures of some coal gasifiers. The product was also shown to be both strong and attrition resistant, and that it can be regenerated by a cyclic oxidation and reduction process. A preliminary evaluation of the material showed that while it was capable of withstanding repeated sulfidation and regeneration, the reactivity of the sorbent tended to decline with usage due to CaO sintering. Also it was found that the compressive strength of the shell material depends on the relative proportions of alumina and limestone as well as their particle size distributions. Therefore, an extensive study of formulation and preparation conditions was conducted to improve the performance of both the core and shell materials. It was subsequently determined that MgO tends to stabilize the high

  2. Economic evaluation of IGCC plants with hot gas cleaning

    International Nuclear Information System (INIS)

    Highlights: ► Techno-economic evaluation of hot gas cleaning IGCC power plants in Germany. ► Scenario analysis in light of nuclear phase-out and outdated coal-fired power plants. ► Consideration of Enhanced Oil Recovery (EOR) and combined heat and power (CHP). ► Economic viability is sensitive to heat-to-power ratio, CHP subsidy, and CO2 price. ► Least-cost investment is not necessarily the one with the lowest GHG emissions. -- Abstract: This paper investigates whether coal-fired Integrated Gasification Combined-Cycle (IGCC) power plants can be an economically viable future technology for providing less carbon-intensive electricity and heat energy in Germany than today. In the context of CO2 emission mitigation in power generation, energy conversion technologies enabling the implementation of Carbon Capture and Storage (CCS) need to be considered. IGCC is such a technology, as it utilizes coal but does not necessarily emit CO2. In our study we investigate, from an economic perspective, whether IGCC plants can be an alternative to nuclear and/or conventional coal-fired power plants. The research is based on scenario analysis. The starting point is the expected shut-down of nuclear power stations and outdated coal-fired power plants, as well as the projected evolution of the CO2 price. The hot gas cleaning option in IGCC plants is of particular interest, as it allows a significant enhancement of the efficiency of the IGCC technology and the use of combined heat and power production (CHP). Corresponding supplementary earnings (incl. subsidies) are compared with an increase in specific investment costs. Besides hot gas cleaning, we also investigate the economic impact of injecting pure CO2 (separated from the IGCC process) into oilfields, as Enhanced Oil Recovery (EOR) can help to reduce the costs of CO2 transport and storage. Based on the results from our analysis we find that the replacement of currently operating power plants by IGCC facilities is only

  3. Sulfur recovery from low H{sub 2}S content acid gas using catalytic partial oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Clark, P.D.; Dowling, N.I.; Huang, M.

    2010-01-15

    The poster presentation discussed a new strategy for recovering sulfur from low hydrogen-sulphide-content acid gas using catalytic partial oxidation. In a new technology for dealing with BTX-contaminated lean acid gas, a catalytic reactor replaces the burner-furnace stage to achieve BTX conversion greater than 95 percent and control the hydrogen sulfide/sulfur dioxide ratio. The product gas is then sent to the Claus catalytic converters. The best catalysts for this process are alumina-supported Co-Mo and y-alumina. This process was compared with SELECTOX, another process that deals with poor acid gas with BTX conversion better than 95 percent. Catalytic oxidation can deal with a higher BTX feed content than SELECTOX, but the running temperature is higher. Both processes produce acceptable sulfur quality. To improve this process, the quality of the sulfur produced and the lifetime of the catalyst need to be increased, and an economic way to increase the heat to reach the running temperature needs to be found. The partial oxidation (POX) of CH{sub 4} solves both of these problems. The catalytic POX of acid gas is combined with the POX of fuel gas in the pre-heating zone. This process has the advantage that the burner-furnace stage of the Claus process can be replaced by a stream containing H{sub 2}S/SO{sub 2}=2; the reaction is performed at its adiabatic temperature requiring only a small amount of fuel gas; the presence of H{sub 2} and CO produced by the POX of fuel gas improves the quality of sulfur; the catalyst remains active for about 30 hours; and the process can tolerate high BTX content. 6 tabs., 2 figs.

  4. Fracture behavior of advanced ceramic hot gas filters: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Singh, J.P.; Majumdar, S.; Sutaria, M.; Bielke, W. [Argonne National Lab., IL (United States). Energy Technology Div.

    1997-03-01

    This report presents the results of mechanical/microstructural evaluation, thermal shock/fatigue testing, and stress analyses of advanced hot-gas filters obtained from different manufacturers. These filters were fabricated from both monolithic ceramics and composites. The composite filters, made of both oxide and nonoxide materials, were in both as-fabricated and exposed conditions, whereas the monolithic filters were made only of nonoxide materials. Mechanical property measurement of composite filters included diametral compression testing with O-ring specimens and burst-testing of short filter segments with rubber plugs. In-situ strength of fibers in the composite filters was evaluated by microscopic technique. Thermal shock/fatigue resistance was estimated by measuring the strengths of filter specimens before and after thermal cycling from an air environment at elevated temperatures to a room temperature oil bath. Filter performance during mechanical and thermal shock/fatigue loadings was correlated with microstructural observations. Micromechanical models were developed to derive properties of composite filter constituents on the basis of measured mechanical properties of the filters. Subsequently, these properties were used to analytically predict the performance of composite filters during thermal shock loading.

  5. Partial catalytic oxidation of CH{sub 4} to synthesis gas for power generation - Final report

    Energy Technology Data Exchange (ETDEWEB)

    Mantzaras, I.; Schneider, A.

    2006-03-15

    The partial oxidation of methane to synthesis gas over rhodium catalysts has been investigated experimentally and numerically in the pressure range of 4 to 10 bar. The methane/oxidizer feed has been diluted with large amounts of H{sub 2}O and CO{sub 2} (up to 70% vol.) in order to simulate new power generation cycles with large exhaust gas recycle. Experiments were carried out in an optically accessible channel-flow reactor that facilitated laser-based in situ measurements, and also in a subscale gas-turbine catalytic reactor. Full-elliptic steady and transient two-dimensional numerical codes were used, which included elementary hetero-/homogeneous chemical reaction schemes. The following are the key conclusions: a) Heterogeneous (catalytic) and homogeneous (gas-phase) schemes have been validated for the partial catalytic oxidation of methane with large exhaust gas recycle. b) The impact of added H{sub 2}O and CO{sub 2} has been elucidated. The added H{sub 2}O increased the methane conversion and hydrogen selectivity, while it decreased the CO selectivity. The chemical impact of CO{sub 2} (dry reforming) was minimal. c) The numerical model reproduced the measured catalytic ignition times. It was further shown that the chemical impact of H{sub 2}O and CO{sub 2} on the catalytic ignition delay times was minimal. d) The noble metal dispersion increased with different support materials, in the order Rh/{alpha}-Al{sub 2}O{sub 3}, Rh/ZrO{sub 2}, and Rh/Ce-ZrO{sub 2}. An evident relationship was established between the noble metal dispersion and the catalytic behavior. (authors)

  6. Effects of Particle Size on the Gas Sensitivity and Catalytic Activity of In2O3

    Science.gov (United States)

    Zhang, Xiaoshui; Gu, Ruiqin; Zhao, Jinling; Jin, Guixin; Zhao, Mengke; Xue, Yongliang

    2015-10-01

    Nanosized In2O3 powders with different particle sizes were prepared by the microemulsion synthetic method. The effects of particle size on the gas-sensing and catalytic properties of the as-prepared In2O3 were investigated. Reductions in particle size to nanometer levels improved the sensitivity and catalytic activity of In2O3 to i-C4H10 and C2H5OH. The sensitivity of nanosized In2O3 (<42 nm) sensors to i-C4H10, H2 and C2H5OH was 2-4 times higher than that of chemically precipitated In2O3 (130 nm) sensor. A nearly linear relationship was observed between the catalytic activity and specific surface area of In2O3 for the oxidation of i-C4H10 and C2H5OH at 275 °C. The relationship between gas sensitivity and catalytic activity was further discussed. The results of this work reveal that catalytic activity plays a key role in enhancing the sensitivity of gas-sensing materials.

  7. Variation in the Deep Gas Composition in Hot Spots on Jupiter

    Science.gov (United States)

    Bjoraker, Gordon; de Pater, Imke; Wong, Michael H.; Adamkovics, Mate; Hewagama, Tilak; Hesman, Brigette

    2015-11-01

    We used CSHELL on NASA’s Infrared Telescope Facility and NIRSPEC on the Keck telescope in the last two years to spectrally resolve line profiles of CH3D, NH3, PH3, and H2O in 5-micron Hot Spots on Jupiter. The profile of the CH3D lines at 4.66 microns is very broad in both NEB and SEB Hot Spots due to collisions with up to 8 bars of H2, where unit optical depth occurs due to collision-induced H2 opacity. The extreme width of these CH3D features implies that the Hot Spots that we observed do not have significant cloud opacity for P > 2 bars. We retrieved NH3, PH3, and gaseous H2O within Hot Spots in both the NEB and SEB. We had dry nights on Mauna Kea and a sufficient Doppler shift to detect H2O. We will compare line wings to derive H2O profiles in the 2 to 6-bar region. NEB Hot Spots are depleted in NH3 with respect to adjacent regions. Interestingly, SEB Hot Spots exhibit stronger NH3 absorption than NEB Hot Spots. In addition, SEB Hot Spots have very similar 5-micron spectra as neighboring longitudes in the SEB, implying similar deep gas composition. The dynamical origin of SEB Hot Spots is much less studied than that of NEB Hot Spots, so our observations of gas composition in both regions may constrain mechanisms for forming Hot Spots.

  8. Reversing flow catalytic converter for a natural gas/diesel dual fuel engine

    Energy Technology Data Exchange (ETDEWEB)

    Liu, E.; Checkel, M.D. [Alberta Univ., Edmonton, AB (Canada). Dept. of Mechanical Engineering; Hayes, R.E. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering; Alberta Univ., Edmonton, AB (Canada). Dept. of Mechanical Engineering; Zheng, M.; Mirosh, E. [Alternative Fuel Systems Inc., Calgary, AB (Canada)

    2001-07-01

    An experimental and modelling study was performed for a reverse flow catalytic converter attached to a natural gas/diesel dual fuel engine. The catalytic converter had a segmented ceramic monolith honeycomb substrate and a catalytic washcoat containing a predominantly palladium catalyst. A one-dimensional single channel model was used to simulate the operation of the converter. The kinetics of the CO and methane oxidation followed first-order behaviour. The activation energy for the oxidation of methane showed a change with temperature, dropping from a value of 129 to 35 kJ/mol at a temperature of 874 K. The reverse flow converter was able to achieve high reactor temperature under conditions of low inlet gas temperature, provided that the initial reactor temperature was sufficiently high. (author)

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

    Science.gov (United States)

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

  10. The generation of electricity by gas turbines using the catalytic combustion of low-Btu gases

    DEFF Research Database (Denmark)

    Frederiksen, O.P.; Qvale, Einar Bjørn

    1989-01-01

    Various systems for the generation of electricity by gas turbines using catalytic combustion of low-Btu gases have been investigated. Parametric studies of three configurations that are deemed to be practically feasible have been completed. It is shown that thermodynamic efficiency of these systems...

  11. Utilization of the Recycle Reactor in Determining Kinetics of Gas-Solid Catalytic Reactions.

    Science.gov (United States)

    Paspek, Stephen C.; And Others

    1980-01-01

    Describes a laboratory scale reactor that determines the kinetics of a gas-solid catalytic reaction. The external recycle reactor construction is detailed with accompanying diagrams. Experimental details, application of the reactor to CO oxidation kinetics, interphase gradients, and intraphase gradients are discussed. (CS)

  12. Reduction of greenhouse gas emissions by catalytic processes

    International Nuclear Information System (INIS)

    Catalytic technologies for the abatement of greenhouse gases (GGs) can be an effective possibility for limiting the increasing tropospheric concentration of GGs and reducing their contribution to global warming. Two different cases are discussed: (1) reduction of anthropogenic emissions of non-CO2 GGs (N2O and CH4) and (2) reduction or conversion of CO2. In methane conversion waste gases containing diluted methane can be converted at low temperature using Pd supported on titania-ceria catalysts which show also a good resistance to deactivation. Rh supported on modified zirconia-alumina catalysts are effective and stable catalysts in low temperature decomposition of N2O. The concept of reduction of CO2 back to fuels in a photo-electrocatalytic reactor is also presented

  13. Effects of Gas Velocity and Temperature on Nitric Oxide Conversion in Simulated Catalytic Converter

    Directory of Open Access Journals (Sweden)

    Sathaporn Chuepeng

    2012-01-01

    Full Text Available Problem statement: Gaseous emissions from gasoline engine such as carbon monoxide, unburned hydrocarbon and nitrogen oxides were usually reduced in three-way catalytic converter simultaneously around theoretical fuel and air combustion. Engine speed and load and other parameters were varied over a wide range of operating conditions, resulting in different exhaust gas composition and condition intake into catalytic converter. This work was studied the conversion of Nitric Oxide (NO in exhaust gas catalytic converter affected by gas velocity and inlet temperature using numerical modeling. Approach: The simulation was based on a one-dimensional time-dependent model within a single monolith channel of the converter. Upon certain assumptions, the study was considered heterogeneous combustion reaction between gas and solid phases based on lumped kinetic reactions. In this study, constants and variables used for mass and heat transfers were dependent on gas or solid phase temperature and mole fraction. Finite difference scheme incorporated with the generated computer code was established for solving species and energy balances within gas and solid phases. Results: The NO conversion was increased with transient period in initial and reached steady state at different values. The lower inlet gas temperature was resulted in lesser NO conversion at the same inlet NO concentration and gas velocity. The light-off temperatures were up to 520 K and a sudden rise in NO conversion was from 550-605 K and decreasing onwards, generating working temperature window. NO conversion increased throughout the catalyst bed from the inlet and the conversion decreased as the gas velocity increased. Conclusion/Recommendations: Gas space velocity and gas temperature intake to the converter affected the NO conversion over the time and the axial distance from the catalyst bed inlet. The numerical results have summarily demonstrated a good approximation compared to experimental

  14. System Study of Rich Catalytic/Lean burn (RCL) Catalytic Combustion for Natural Gas and Coal-Derived Syngas Combustion Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Shahrokh Etemad; Lance Smith; Kevin Burns

    2004-12-01

    Rich Catalytic/Lean burn (RCL{reg_sign}) technology has been successfully developed to provide improvement in Dry Low Emission gas turbine technology for coal derived syngas and natural gas delivering near zero NOx emissions, improved efficiency, extending component lifetime and the ability to have fuel flexibility. The present report shows substantial net cost saving using RCL{reg_sign} technology as compared to other technologies both for new and retrofit applications, thus eliminating the need for Selective Catalytic Reduction (SCR) in combined or simple cycle for Integrated Gasification Combined Cycle (IGCC) and natural gas fired combustion turbines.

  15. Numerical Investigation of the Transient Behavior of a Hot Gas Duct under Rapid Depressurization

    Directory of Open Access Journals (Sweden)

    JingBao Liu

    2016-01-01

    Full Text Available A hot gas duct is an indispensable component for the nuclear-process heat applications of the Very-High-Temperature Reactor (VHTR, which has to fulfill three requirements: to withstand high temperature, high pressure, and large pressure transient. In this paper, numerical investigation of pressure transient is performed for a hot gas duct under rapid depressurization. System depressurization imposes an imploding pressure differential on the internal structural elements of a hot gas duct, the structural integrity of which is susceptible to being damaged. Pressure differential and its imposed duration, which are two key factors to evaluate the damage severity of a hot gas duct under depressurization, are examined in regard to depressurization rate and insulation packing tightness. It is revealed that depressurization rate is a decisive parameter for controlling the pressure differential and its duration, whereas insulating-packing tightness has little effect on them.

  16. Recent advances in catalytic combustion for ground power gas turbine engines

    Energy Technology Data Exchange (ETDEWEB)

    Smith, L.L.; Karim, H.; Castaldi, M.; Etemad, S.; Pfefferle, W.C.; Newburry, D.; Bachovchin, D.

    1999-07-01

    Catalytic combustion is one means of meeting increasingly strict emissions requirements for ground-based gas turbine engines for power generation. In conventional homogeneous combustion, high flame temperatures and incomplete combustion lead to emissions of oxides of nitrogen (NO{sub x}) and carbon monoxide (CO), and in lean premixed systems unburned hydrocarbons (UHC). However, catalytic reaction upstream of a lean premixed homogeneous combustion zone can increase the fuel/air mixture reactivity sufficiently to allow low CO/UHC emissions at adiabatic flame temperatures below 1,500 C, with concurrent low NO{sub x} emissions. As a result, catalytic combustion technologies have demonstrated single-digit emissions, and meet DOE-ATS goals (NO{sub x} {lt} 10 ppm, and CO/UHC {lt} 20 ppm) by a wide margin. Precision Combustion, Inc. (PCI) is currently developing catalytic combustion systems for Siemens Westinghouse Power Corporation. For natural gas fuel operation, PCI has demonstrated NO{sub x} {lt} 5 ppm, CO {lt} 1 ppm, and UHC {lt} 1 ppm (all corrected to 15% O2) in a sub-scale atmospheric rig, using a catalytic pre-reactor upstream of the combustion zone. For these tests, gas-phase combustion was stabilized in an 8-inch diameter convection-cooled metal liner at adiabatic flame temperatures from 1,250 C to 1,550 C. In parallel, extensive high pressure reactor component development and testing have been conducted at sub-scale, in preparation for high pressure testing of a full-scale catalytic combustor.

  17. The origin of the hot metal-poor gas in NGC 1291 - Testing the hypothesis of gas dynamics as the cause of the gas heating

    NARCIS (Netherlands)

    Perez, [No Value; Freeman, K

    2006-01-01

    In this paper we test the idea that the low-metallicity hot gas in the centre of NGC 1291 is heated via a dynamical process. In this scenario, the gas from the outer gas-rich ring loses energy through bar-driven shocks and falls to the centre. Heating of the gas to X-ray temperatures comes from the

  18. Catalytic and Gas-Solid Reactions Involving HCN over Limestone

    DEFF Research Database (Denmark)

    Jensen, Anker; Johnsson, Jan Erik; Dam-Johansen, Kim

    1997-01-01

    In coal-fired combustion systems solid calcium species may be present as ash components or limestone added to the combustion chamber. In this study heterogeneous reactions involving HCN over seven different limestones were investigated in a laboratory fixed-bed quartz reactor at 873-1,173 K....... Calcined limestone is an effective catalyst for oxidation of HCN. Under conditions with complete conversion of HCN at O-2 concentrations above about 5,000 ppmv the selectivity for formation of NO and N2O is 50-70% and below 5%, respectively. Nitric oxide can be reduced by HCN to N-2 in the absence of O-2...... and to N-2 and N2O in the presence of O-2. At low O-2 concentrations or low temperatures. HCN may react with CaO, forming calcium cyanamide, CaCN2. The selectivities for formation of NO and N2O from oxidation of CaCN2 is 20-25% for both species. The catalytic activity of limestone for oxidation of HCN...

  19. Avoiding Carbon Bed Hot Spots in Thermal Process Off-Gas Systems

    Energy Technology Data Exchange (ETDEWEB)

    Nick Soelberg; Joe Enneking

    2011-05-01

    Mercury has had various uses in nuclear fuel reprocessing and other nuclear processes, and so is often present in radioactive and mixed (radioactive and hazardous) wastes. Test programs performed in recent years have shown that mercury in off-gas streams from processes that treat radioactive wastes can be controlled using fixed beds of activated sulfur-impregnated carbon, to levels low enough to comply with air emission regulations such as the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards. Carbon bed hot spots or fires have occurred several times during these tests, and also during a remediation of tanks that contained mixed waste. Hot spots occur when localized areas in a carbon bed become heated to temperatures where oxidation occurs. This heating typically occurs due to heat of absoption of gas species onto the carbon, but it can also be caused through external means such as external heaters used to heat the carbon bed vessel. Hot spots, if not promptly mitigated, can grow into bed fires. Carbon bed hot spots and fires must be avoided in processes that treat radioactive and mixed waste. Hot spots are detected by (a) monitoring in-bed and bed outlet gas temperatures, and (b) more important, monitoring of bed outlet gas CO concentrations. Hot spots are mitigated by (a) designing for appropriate in-bed gas velocity, for avoiding gas flow maldistribution, and for sufficient but not excessive bed depth, (b) appropriate monitoring and control of gas and bed temperatures and compositions, and (c) prompt implementation of corrective actions if bed hot spots are detected. Corrective actions must be implemented quickly if bed hot spots are detected, using a graded approach and sequence starting with corrective actions that are simple, quick, cause the least impact to the process, and are easiest to recover from.

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

    Energy Technology Data Exchange (ETDEWEB)

    Trewyn, Brian G.; Smith, Ryan G.

    2016-07-05

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Trewyn, Brian G. [Colorado School of Mines, Golden, CO (United States); Smith, Ryan G. [Iowa State Univ., Ames, IA (United States)

    2016-06-01

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

  2. Reactors for Catalytic Methanation in the Conversion of Biomass to Synthetic Natural Gas (SNG).

    Science.gov (United States)

    Schildhauer, Tilman J; Biollaz, Serge M A

    2015-01-01

    Production of Synthetic Natural Gas (SNG) from biomass is an important step to decouple the use of bioenergy from the biomass production with respect to both time and place. While anaerobic digestion of wet biomass is a state-of-the art process, wood gasification to producer gas followed by gas cleaning and methanation has only just entered the demonstration scale. Power-to-Gas applications using biogas from biomass fermentation or producer gas from wood gasification as carbon oxide source are under development. Due to the importance of the (catalytic) methanation step in the production of SNG from dry biomass or within Power-to-Gas applications, the specific challenges of this step and the developed reactor types are discussed in this review. PMID:26598404

  3. 30 CFR 77.305 - Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Access to drying chambers, hot gas inlet... drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. Drying chambers, hot... dust and the loss of fluidizing air....

  4. The Scatter in the Hot Gas Content of Early-Type Galaxies

    CERN Document Server

    Su, Yuanyuan; White, Raymond E; Cooper, Michael C

    2015-01-01

    Optically-similar early-type galaxies are observed to have a large and poorly understood range in the amount of hot, X-ray-emitting gas they contain.To investigate the origin of this diversity, we studied the hot gas properties of all 42 early-type galaxies in the multiwavelength ATLAS$^{\\rm 3D}$ survey that have sufficiently deep {\\sl Chandra} X-ray observations. We related their hot gas properties to a number of internal and external physical quantities. To characterize the amount of hot gas relative to the stellar light, we use the ratio of the gaseous X-ray luminosity to the stellar $K$-band luminosity, $L_{X_{\\rm gas}}/L_K$; we also use the deviations of $L_{X_{\\rm gas}}$ from the best-fit $L_{X_{\\rm gas}}$--$L_K$ relation (denoted $\\Delta L_{X_{\\rm gas}}$). We quantitatively confirm previous suggestions that various effects conspire to produce the large scatter in the observed $L_X/L_K$ relation. In particular, we find that the deviations $\\Delta L_{X_{\\rm gas}}$ are most strongly positively correlated ...

  5. O VII and O VIII absorption by hot gas in the vicinity of the Galaxy

    CERN Document Server

    McKernan, B; Reynolds, C S

    2004-01-01

    (abridged) We searched for evidence of soft X-ray absorption by hot gas in the vicinity of the Galaxy in a small sample of fifteen type I AGN observed with the high resolution X-ray gratings on board Chandra. We find that around half of the sight lines in our sample exhibit absorption due to local H- or He-like Oxygen (or both) at confidence levels ranging from >90% to >3sigma. Depending on the sight line, the absorption can be identified with hot gas in particular local structures, the Local Group (LG) or the putative local hot intergalactic medium (IGM). Several sight lines in our sample coincide with sight lines in a study of O VI absorption by local gas, so an assumption of collisional ionization equilibrium (CIE) allows us to constrain the temperature of the local hot gas. We show that hot absorbing outflows apparently detected in the spectra of NGC 4051, PDS 456 and PG 1211+143 respectively could actually correspond to absorption by hot local gas since the outflow velocity from each of these AGN coincid...

  6. Novel catalytic converter for natural gas powered diesel engines to meet stringent exhaust emission regulations

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, M.; Mirosh, E.A. [Alternative Fuel Systems Inc. (Canada); Matros, Yu.S.; Bunimovich, G.A.; Strots, V.O. [Matros Technologies Inc. (United States); Sallamie, N.; Checkel, M.D. [Alberta Univ. (Canada); Windawi, H. [Johnson Matthey (United States)

    1998-12-31

    The implementation of stringent exhaust emission regulations has led to the development of natural gas powered dual fuel systems with electronic multiport injection. The high compression ratio of the baseline diesel engine was maintained to keep the high thermal efficiency of diesel cycles. The dual fuel system is mainly powered by natural gas and ignited by a diesel pilot. Extensive experimental results indicate that the diesel dual fuel system provides simultaneous reductions in NO{sub x} and particulate emissions. The system also has low exhaust THC and CO under heavy-duty operations. With the combined use of exhaust gas recirculation and catalytic converter, low emission operation has been extended to a larger range, from medium to full loads for all testing speeds. However, conventional converters exhibit poor conversion efficiency at low engine loads due to the low exhaust temperature levels. This leads to increased exhaust emissions during low load operations, especially for the non-reactive hydrocarbons, specifically, methane. To solve this problem, a novel automotive exhaust gas aftertreatment system - the reversing flow catalytic converter - has been developed. The prototype Reversing Flow Converter (RFC) consists of a diversion flow valve and a catalytic monolith converter. The diversion valve periodically re-directs the engine exhaust flow through the catalyst in alternative directions. The duration of flow in each direction is determined by engine operating conditions to obtain an ideal temperature profile along the axis of the monolith. The catalytic converter was designed to have high methane conversion efficiency. Associated techniques, such as retarding fuel injection, exhaust gas recirculation, and the variation of diesel pilot to natural gas ratio, can be used to raise exhaust temperature and bring the catalytic converter to light-off temperatures quicker. Engine dynamometer tests showed that CO conversion rate was above 95% and CH{sub 4

  7. Long-time experience in catalytic flue gas cleaning and catalytic NO{sub x} reduction in biofueled boilers

    Energy Technology Data Exchange (ETDEWEB)

    Ahonen, M. [Tampella Power Inc., Tampere (Finland)

    1996-12-31

    NO emissions are reduced by primary or secondary methods. Primary methods are based on NO reduction in the combustion zone and secondary methods on flue gas cleaning. The most effective NO reduction method is selective catalytic reduction (SCR). It is based on NO reduction by ammonia on the surface of a catalyst. Reaction products are water and nitrogen. A titanium-dioxide-based catalyst is very durable and selective in coal-fired power plants. It is not poisoned by sulphur dioxide and side reactions with ammonia and sulphur dioxide hardly occur. The long time experience and suitability of a titanium-dioxide-based catalyst for NO reduction in biofuel-fired power plants was studied. The biofuels were: peat, wood and bark. It was noticed that deactivation varied very much due to the type of fuel and content of alkalinities in fuel ash. The deactivation in peat firing was moderate, close to the deactivation noticed in coal firing. Wood firing generally had a greater deactivation effect than peat firing. Fuel and fly ash were analyzed to get more information on the flue gas properties. The accumulation of alkali and alkaline earth metals and sulphates was examined together with changes in the physical composition of the catalysts. In the cases where the deactivation was the greatest, the amount of alkali and alkaline earth metals in fuels and fly ashes and their accumulation were very significant. (author) (3 refs.)

  8. Dust In Hell: Discovery Of Dust In Hot Gas Around Group-Centered Elliptical Galaxies

    Science.gov (United States)

    Temi, Pasquale; Brighenti, F.; Mathews, W. G.

    2007-05-01

    Observations with the Spitzer infrared telescope reveal extended internally produced dust in the hot gas (KT 1 KeV) atmospheres surrounding two optically normal galaxies, NGC 5044 and NGC 4636. We interpret this as a dusty buoyant outflow resulting from energy released by gas accretion onto supermassive black holes in the galaxy cores. Both galaxies have highly disturbed, transient activities in the hot gas and contain strong dust emission at 70 and 160 microns in excess of what expected from normal stellar mass loss. The 70 micron image is clearly extended. The lifetime of dust in hot (KT=1KeV) interstellar gas to destruction by sputtering (ion impacts), 10 million years, establishes the time when the dust first entered the hot gas. Remarkably, in NGC 5044 we observe interstellar PAH dust-molecular emission at 8 microns out to about 5 Kpc that is spatially coincident with extended Halpha+[NII] emission from warm gas. We propose that this dust comes from the destruction and heating of dusty disks in the nuclei of these galaxies, followed by buoyant transport. A simple calculation shows that dust-assisted cooling in outflowing buoyant gas in NGC 5044 can cool the gas within a few Kpc in about 10 million years, explaining the optical line emission observed.

  9. Hot gas handling device and motorized vehicle comprising the device

    NARCIS (Netherlands)

    Klein Geltink, J.; Beukers, A.; Van Tooren, M.J.L.; Koussios, S.

    2012-01-01

    The invention relates to a device for handling hot exhaust gasses discharged from an internal combustion engine. The device comprises a housing (2), enclosing a space (3) for transporting the exhaust gasses. The housing (2) is provided with an entrance - opening (4) for the exhaust gasses discharged

  10. Hot Gas Cleanup Test Facility for gasification and pressurized combustion. Quarterly report, October--December 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-02-01

    The objective of this project is to evaluate hot gas particle control technologies using coal-derived gas streams. This will entail the design, construction, installation, and use of a flexible test facility which can operate under realistic gasification and combustion conditions. The major particulate control device issues to be addressed include the integration of the particulate control devices into coal utilization systems, on-line cleaning techniques, chemical and thermal degradation of components, fatigue or structural failures, blinding, collection efficiency as a function of particle size, and scale-up of particulate control systems to commercial size. The conceptual design of the facility was extended to include a within scope, phased expansion of the existing Hot Gas Cleanup Test Facility Cooperative Agreement to also address systems integration issues of hot particulate removal in advanced coal-based power generation systems. This expansion included the consideration of the following modules at the test facility in addition to the original Transport Reactor gas source and Hot Gas Cleanup Units: carbonizer/pressurized circulating fluidized bed gas source; hot gas cleanup units to mate to all gas streams; combustion gas turbine; and fuel cell and associated gas treatment. The major emphasis during this reporting period was continuing the detailed design of the facility and integrating the particulate control devices (PCDs) into structural and process designs. Substantial progress in underground construction activities was achieved during the quarter. Delivery and construction of coal handling and process structural steel began during the quarter. Delivery and construction of coal handling and process structural steel began during the quarter. MWK equipment at the grade level and the first tier are being set in the structure.

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

    Science.gov (United States)

    Sun, Tonghua; Shen, Yafei; Jia, Jinping

    2014-02-18

    This paper proposes a novel self-developed JTS-01 desulfurizer and JZC-80 alkaline adsorbent for H2S removal and gas cleaning of the COREX coal gas in small-scale and commercial desulfurizing devices. JTS-01 desulfurizer was loaded with metal oxide (i.e., ferric oxides) catalysts on the surface of activated carbons (AC), and the catalyst capacity was improved dramatically by means of ultrasonically assisted impregnation. Consequently, the sulfur saturation capacity and sulfur capacity breakthrough increased by 30.3% and 27.9%, respectively. The whole desulfurizing process combined selective adsorption with catalytic oxidation. Moreover, JZC-80 adsorbent can effectively remove impurities such as HCl, HF, HCN, and ash in the COREX coal gas, stabilizing the system pressure drop. The JTS-01 desulfurizer and JZC-80 adsorbent have been successfully applied for the COREX coal gas cleaning in the commercial plant at Baosteel, Shanghai. The sulfur capacity of JTS-01 desulfurizer can reach more than 50% in industrial applications. Compared with the conventional dry desulfurization process, the modified AC desulfurizers have more merit, especially in terms of the JTS-01 desulfurizer with higher sulfur capacity and low pressure drop. Thus, this sorption enhanced catalytic desulfurization has promising prospects for H2S removal and other gas cleaning. PMID:24456468

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

    Science.gov (United States)

    Sun, Tonghua; Shen, Yafei; Jia, Jinping

    2014-02-18

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

  13. Novel Gas Barrier SiOC Coating to PET Bottles through a Hot Wire CVD Method

    OpenAIRE

    Nakaya, Masaki; Kodama, Kenji; Yasuhara, Shigeo; Hotta, Atsushi

    2016-01-01

    In an attempt to enhance the gas barrier enhancement of plastic containers such as poly(ethylene terephthalate) bottles, a novel method was found using a hot wire CVD technique, where tantalum wire is heated and exposed to a gas flow of vinyl silane. The resultant SiOC thin film was confirmed to characteristically contain Si-Si bonds in its surface and demonstrate a remarkably and highly practical decrease of the permeation of various gas through poly(ethylene terephthalate) bottles.

  14. Evaluating the Hot Corrosion Behavior of High-Temperature Alloys for Gas Turbine Engine Components

    Science.gov (United States)

    Deodeshmukh, V. P.

    2015-11-01

    The hot corrosion behavior of high-temperature alloys is critically important for gas turbine engine components operating near the marine environments. The two test methods—Two-Zone and Burner-Rig—used to evaluate the hot corrosion performance of high-temperature alloys are illustrated by comparing the Type I hot corrosion behavior of selected high-temperature alloys. Although the ranking of the alloys is quite comparable, it is evident that the two-zone hot corrosion test is significantly more aggressive than the burner-rig test. The effect of long-term exposures and the factors that influence the hot corrosion performance of high-temperature alloys are briefly discussed.

  15. Hot gas handling device and motorized vehicle comprising the device

    OpenAIRE

    Klein Geltink, J.; Beukers, A.; Van Tooren, M.J.L.; Koussios, S.

    2012-01-01

    The invention relates to a device for handling hot exhaust gasses discharged from an internal combustion engine. The device comprises a housing (2), enclosing a space (3) for transporting the exhaust gasses. The housing (2) is provided with an entrance - opening (4) for the exhaust gasses discharged from the engine and an exit-opening (5) for transporting the exhaust gasses away from the engine, and comprises a flexible thermal insulating layer, arranged for resisting the temperature of the e...

  16. Studies and development of high-temperature catalytic materials for application in gas turbine combustion chamber

    Energy Technology Data Exchange (ETDEWEB)

    Papadias, Dennis; Thevenin, Philippe [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Chemical Engineering and Technology

    2000-04-01

    -based garnets and aluminium titanate. The NZP materials (NaZr{sub 2}(PO{sub 4}){sub 3}) have an ultra-low thermal expansion which gives them the desired properties to stand thermal shocks. However their catalytic activity needs to be improved as they have a T{sub 50} above 520 deg C. The iron containing garnets (YIG) with the following formula Y{sub 3}Fe{sub 5}O{sub 12}, as well as the MgAl{sub 2}O{sub 4} spinel, show promising results with an activity close to the hexaaluminates. Different fuels could be considered for application in gas turbine combustion chambers. Ethanol appears to be a promising alternative fuel for mobile gas turbines, methane and gasified biomass for stationary utilisation. The experimental work in this project has been done using ethanol as fuel. The coming work will be oriented towards gasified biomass as well. Specific attention will be given to fuel-NO{sub x} formation from the ammonia present in the feed. The work was carried out in co-operation with Volvo Aero Corporation, which was involved in the European project AGATA where the objective was to develop a ceramic gas turbine for hybrid car applications. Furthermore, another project within catalytic combustion for gas turbine is conducted in co-operation with the Division of Heat and Power Technology at KTH (Nutek project P7057, Catalytic Combustion of Gasified Biomass). In this projects a fully catalytic system has been chosen. However a solution to overcome the problem given by the high temperature present in the last section of the combustor is a hybrid system described in the literature. A first catalyst segment with low temperature catalytic activity ignites part of the fuel at 300-400 deg C. The rest of the fuel is then burned homogeneously between 1000 - 1400 deg C. This design avoid the use of catalytic material at temperature above 1000 deg C. Different projects are running both in the US (Catalytica Combustion Systems Inc., Precision Combustion) and Japan (Osaka Gas Company) to develop a

  17. Analysis on Service Life of Hot-end Components of Gas Turbine Using Equivalent Operation

    Directory of Open Access Journals (Sweden)

    Taixing Wang

    2013-01-01

    Full Text Available The reliability of the gas turbine depends on the technical status and the maintenance level of the hot-end components in a large part.The three main factors influencing on the service life of the hot-end components of the gas turbine were analyzed first.On this basis,various common service life assessment methods for gas turbine were discussed in detail.Aiming at the features of the M701F gas-steam combined cycle unit in Huizhou LNG power plant,a gas turbine life assessment method based on equivalent operation time analysis was put forward.The calculation result of an example shows that the equivalent operation time analysis method is a simple and practical assessment method.

  18. Hot Gas in Clusters of Galaxies the Punctuated Equilibria Model

    CERN Document Server

    Cavaliere, A; Tozzi, P

    1998-01-01

    We develop a model to describe the evolution of the intra-cluster X-ray emitting baryons. These are included in the potential wells of galaxy clusters evolving through subsequent merging events in the framework of hierarchical clustering. The gas is assumed to re-adjusts to a new hydrostatic equilibrium after each merging event. Before merging it is gravitationally heated at the local virial temperature when bound in subclusters; at early $z$ the gas is preheated by supernova activity following star formation. In detail, we compute analytically the following steps: the dynamic histories of dark matter halos with their merging events; the associated infall of gas into a halo, with compressions and shocks estabilishing the conditions at the cluster boundary; the updated disposition of the gas in the potential well matching such conditions; the statistical convolution of the key quantities over the merging histories. The model predicts the density and surface brightness profiles with no free parameters; the so-c...

  19. Hot Gas TVC For Planetary Ascent Vehicle Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A Mars ascent vehicle (MAV) uses solid rocket motors to propel soil samples into orbit, but the motors cannot provide steering. Cold gas thrusters are used for...

  20. Catalytically upgraded landfill gas as a cost-effective alternative for fuel cells

    Science.gov (United States)

    Urban, W.; Lohmann, H.; Gómez, J. I. Salazar

    The potential use of landfill gas as feeding fuel for the so-called molten carbonate fuel cells (MCFC) imposes the need for new upgrading technologies in order to meet the much tougher feed gas specifications of this type of fuel cells in comparison to gas engines. Nevertheless, MCFC has slightly lower purity demands than low temperature fuel cells. This paper outlines the idea of a new catalytic purification process for landfill gas conditioning, which may be supposed to be more competitive than state-of-the-art technologies and summarises some lab-scale results. This catalytic process transforms harmful landfill gas minor compounds into products that can be easily removed from the gas stream by a subsequent adsorption step. The optimal process temperature was found to be in the range 250-400 °C. After a catalyst screening, two materials were identified, which have the ability to remove all harmful minor compounds from landfill gas. The first material was a commercial alumina that showed a high activity towards the removal of organic silicon compounds. The alumina protects both a subsequent catalyst for the removal of other organic minor compounds and the fuel cell. Due to gradual deactivation caused by silica deposition, the activated alumina needs to be periodically replaced. The second material was a commercial V 2O 5/TiO 2-based catalyst that exhibited a high activity for the total oxidation of a broad spectrum of other harmful organic minor compounds into a simpler compound class "acid gases (HCl, HF and SO 2)", which can be easily removed by absorption with, e.g. alkalised alumina. The encouraging results obtained allow the scale-up of this LFG conditioning process to test it under real LFG conditions.

  1. Gas cleaning, gas conditioning and tar abatement by means of a catalytic filter candle in a biomass fluidized-bed gasifier.

    Science.gov (United States)

    Rapagnà, Sergio; Gallucci, Katia; Di Marcello, Manuela; Matt, Muriel; Nacken, Manfred; Heidenreich, Steffen; Foscolo, Pier Ugo

    2010-09-01

    A bench-scale fluidized-bed biomass gasification plant, operating at atmospheric pressure and temperature within the range 800-820 degrees C, has been used to test an innovative gas cleaning device: a catalytic filter candle fitted into the bed freeboard. This housing of the gas conditioning system within the gasifier itself results in a very compact unit and greatly reduced thermal losses. Long term (22h) tests were performed on the gasifier both with and without the catalytic candle filter, under otherwise identical conditions. Analysis of the product gas for the two cases showed the catalytic filtration to give rise to notable improvements in both gas quality and gas yield: an increase in hydrogen yield of 130% and an overall increase in gas yield of 69% - with corresponding decreases in methane and tar content of 20% and 79%, respectively. HPLC/UV analysis was used to characterize the tar compounds.

  2. Performance of CaO and MgO for the hot gas clean up in gasification of a chlorine-containing (RDF) feedstock.

    Science.gov (United States)

    Corella, José; Toledo, José M; Molina, Gregorio

    2008-11-01

    Calcined limestone (CaO) and calcined dolomite (CaO.MgO) were tested at bench scale to study their usefulness in cleaning hot raw gas from a fluidized bed gasifier of a synthetic or simulated refuse-derived fuel (RDF) with a high (3 wt%) content in chlorine. In the gas cleaning reactor two main reactions occurred simultaneously: the elimination of HCl and the elimination of tar by steam reforming. The elimination of HCl formed CaCl2 and MgCl2 with melting points below the high (above 800 degrees C) temperatures required for the simultaneous tar elimination reaction. So, the CaO-based particles progressively melted and the catalytic gas cleaning reactor became a compact, agglomerated or glued, cake. Therefore, the life and usefulness of the CaO-based solids used was very low. Nevertheless, and to further avoid these problems, some positive guidelines for future research are proposed here. PMID:18372172

  3. Dynamic S0 Galaxies II: the Role of Diffuse Hot Gas

    CERN Document Server

    Li, Jiang-Tao; Li, Zhiyuan; Chen, Yang

    2011-01-01

    Gas loss is thought to be important in SF quenching and morphological transition during the evolution of S0 galaxies. In high density environments, gas loss can be achieved via many external mechanisms. However, in relatively isolated environments, where these external mechanisms cannot be efficient, gas loss must be dominated by some internal processes. We perform Chandra analysis of hot gas in five nearby isolated S0 galaxies, based on quantitative subtraction of various stellar contributions. We find that all the galaxies studied in the present work are X-ray faint, with the hot gas luminosity LX<5% of the expected Ia SN energy injection rate. We further compare our results with those from relevant recent papers, in order to investigate the energy budget, cold-hot gas relation, and gas removal from S0 galaxies in isolated environments. We find that elliptical and S0 galaxies are not significantly different in LX at the low mass end (typically with LK<1e11Lsun). However, at the high mass end, S0 galax...

  4. Selective catalytic reduction (SCR) NOx control for small natural gas-fired prime movers

    International Nuclear Information System (INIS)

    The application of selective catalytic reduction (SCR) to small natural gas-fired prime movers at cogeneration facilities and compressor stations could possibly increase due to regulatory forces to limit NOx from such sources. The natural gas industry is presently without a current database with which to evaluate the cost and operating characteristics of SCR under the conditions anticipated for small prime movers. This paper presents the results from a two-phase study undertaken to document SCR applications with emphasis on SCR system performance and costs. The database of small natural gas-fired prime mover SCR experience, focusing on prime mover characterization, SCR system performance, and SCR system costs will be described. Result from analysis of performance and cost data will be discussed, including analytical tools developed to project SCR system performance and costs

  5. Numerical study of the generation of runaway electrons in a gas diode with a hot channel

    International Nuclear Information System (INIS)

    A new method for increasing the efficiency of runaway electron beam generation in atmospheric pressure gas media has been suggested and theoretically proved. The method consists of creating a hot region (e.g., a spark channel or a laser plume) with a decreased numerical density of gas molecules (N) near the cathode. In this method, the ratio E/N (E—electric field strength) is increased by decreasing N instead of increasing E, as has been done in the past. The numerical model that is used allows the simultaneous calculation of the formation of a subnanosecond gas discharge and the generation of runaway electrons in gas media. The calculations have demonstrated the possibility of obtaining current pulses of runaway electrons with amplitudes of hundred of amperes and durations of more than 100 ps. The influence of the hot channel geometry on the parameters of the generated beam has been investigated

  6. Numerical study of the generation of runaway electrons in a gas diode with a hot channel

    Energy Technology Data Exchange (ETDEWEB)

    Lisenkov, V. V., E-mail: lisenkov@iep.uran.ru [Institute of Electrophysics UrB RAS, 106 Amundsena St., Ekaterinburg 620012 (Russian Federation); Ural Federal University, 19 Mira St., Ekaterinburg 620002 (Russian Federation); Shklyaev, V. A., E-mail: shklyaev@to.hcei.tsc.ru [Institute of High Current Electronics SD RAS, 2/3 Akademichesky Avenue, 634055 Tomsk (Russian Federation); National Research Tomsk Polytechnic University, 30 Lenin Avenue, 634050 Tomsk (Russian Federation)

    2015-11-15

    A new method for increasing the efficiency of runaway electron beam generation in atmospheric pressure gas media has been suggested and theoretically proved. The method consists of creating a hot region (e.g., a spark channel or a laser plume) with a decreased numerical density of gas molecules (N) near the cathode. In this method, the ratio E/N (E—electric field strength) is increased by decreasing N instead of increasing E, as has been done in the past. The numerical model that is used allows the simultaneous calculation of the formation of a subnanosecond gas discharge and the generation of runaway electrons in gas media. The calculations have demonstrated the possibility of obtaining current pulses of runaway electrons with amplitudes of hundred of amperes and durations of more than 100 ps. The influence of the hot channel geometry on the parameters of the generated beam has been investigated.

  7. A Reusable Calcium-Based Sorbent for Desulfurizing Hot Coal Gas

    Energy Technology Data Exchange (ETDEWEB)

    Wheelock, T.D.; Hasler, D.J.L.

    2002-09-19

    The overall objective of this project has been to develop a superior, regenerable, calcium-based sorbent for desulfurizing hot coal gas. The sorbent should be strong, durable, inexpensive to manufacture, and capable of being reused many times. To achieve these objectives the project has focused on the development of the very promising core-in-shell sorbent.

  8. The Milky Way's Hot Gas Kinematics: Signatures in Current and Future OVII Absorption Line Observations

    CERN Document Server

    Miller, Matthew J; Bregman, Joel N

    2016-01-01

    Detections of $z \\approx$ 0 oxygen absorption and emission lines indicate the Milky Way hosts a hot ($\\sim 10^6$ K), low-density plasma extending $\\gtrsim$50 kpc into the Mily Way's halo. Current X-ray telescopes cannot resolve the line profiles, but the variation of their strengths on the sky constrains the radial gas distribution. Interpreting the OVII K$\\alpha$ absorption line strengths has several complications, including optical depth and line of sight velocity effects. Here, we present model absorption line profiles accounting for both of these effects to show the lines can exhibit asymmetric structures and be broader than the intrinsic Doppler width. The line profiles encode the hot gas rotation curve, the net inflow or outflow of hot gas, and the hot gas angular momentum profile. We show how line of sight velocity effects impact the conversion between equivalent width and the column density, and provide modified curves of growth accounting for these effects. As an example, we analyze the LMC sight lin...

  9. Antifuse nano-hot-spot device on a suspended membrane for gas sensing applications

    NARCIS (Netherlands)

    Iordache, G.; Holleman, J.; Kovalgin, A.Y.; Jenneboer, A.J.S.M.

    2003-01-01

    We have designed and realized a new antifuse hot-spot device to be used in gas sensing applications. The antifuse structure was realized on a suspended membrane to minimize the heat losses. For the sensing of alkanes a procedure for making a porous alumina layer doped with Platinum was developed. Th

  10. Removal of nitrogen compounds from gasification gas by selective catalytic or non-catalytic oxidation; Typpiyhdisteiden poisto kaasutuskaasusta selektiivisellae katalyyttisellae ja ei-katalyyttisellae hapetuksella

    Energy Technology Data Exchange (ETDEWEB)

    Leppaelahti, J.; Koljonen, T. [VTT Energy, Espoo (Finland)

    1996-12-01

    In gasification reactive nitrogenous compounds are formed from fuel nitrogen, which may form nitrogen oxides in gas combustion. In fluidized bed gasification the most important nitrogenous compound is ammonia (NH{sub 3}). If ammonia could be decomposed to N{sub 2} already before combustion, the emissions if nitrogen oxides could be reduced significantly. One way of increasing the decomposition rate of NH{sub 3} could be the addition of suitable reactants to the gas, which would react with NH{sub 3} and produce N{sub 2}. The aim of this research is to create basic information, which can be used to develop a new method for removal of nitrogen compounds from gasification gas. The reactions of nitrogen compounds and added reactants are studied in reductive atmosphere in order to find conditions, in which nitrogen compounds can be oxidized selectively to N{sub 2}. The project consists of following subtasks: (1) Selective non-catalytic oxidation (SNCO): Reactions of nitrogen compounds and oxidizers in the gas phase, (2) Selective catalytic oxidation (SCO): Reactions of nitrogen compounds and oxidizers on catalytically active surfaces, (3) Kinetic modelling of experimental results in co-operation with the Combustion Chemistry Research Group of Aabo Akademi University. The most important finding has been that NH{sub 3} can be made to react selectively with the oxidizers even in the presence of large amounts of CO and H{sub 2}. Aluminium oxides were found to be the most effective materials promoting selectivity. (author)

  11. Electrochemical Synthesis of Mo2C Catalytical Coatings for the Water-Gas Shift Reaction

    Science.gov (United States)

    Kuznetsov, Sergey A.; Dubrovskiy, Anton R.; Rebrov, Evgeny V.; Schouten, Jaap C.

    2007-11-01

    The electroreduction of CO32- ions on a molybdenum cathode in a NaCl-KCl-Li2CO3 melt was studied by cyclic voltammetry. The electrochemical synthesis of Mo2C on molybdenum substrates has been performed at 1123 K for 7 h with a cathodic current density of 5 mA cm-2. If molybdenum carbide is present as a thin (ca. 500 nm) film on a molybdenum substrate (Mo2C/Mo), its catalytic activity in the water gas-shift reaction is enhanced by at least an order of magnitude compared to that of the bulk Mo2C phase.

  12. Origin of the hot gas in low-mass protostars

    DEFF Research Database (Denmark)

    Van Kempen, T. A.; Kristensen, L. E.; Herczeg, G. J.;

    2010-01-01

    , which are heated by UV photons and non-dissociative C-type shocks. The bright OH and [O i] emission is attributed to J-type shocks in dense gas close to the protostar. In the scenario described here, the combined cooling by far-IR lines within the central spatial pixel is estimated to be 2 × 10-2 L...... in the outflow. In addition, [O i] emission is seen in low-velocity gas, assumed to be related to the envelope, and is also seen shifted up to 170 km s-1 in both the red-and blue-shifted jets. Envelope models are constructed based on previous observational constraints. They indicate that passive heating...... of a spherical envelope by the protostellar luminosity cannot explain the high-excitation molecular gas detected with PACS, including CO lines with upper levels at >2500 K above the ground state. Instead, warm CO and H2O emission is probably produced in the walls of an outflow-carved cavity in the envelope...

  13. Origin of the hot gas in low-mass protostars

    DEFF Research Database (Denmark)

    Van Kempen, T. A.; Kristensen, L. E.; Herczeg, G. J.;

    2010-01-01

    , which are heated by UV photons and non-dissociative C-type shocks. The bright OH and [O i] emission is attributed to J-type shocks in dense gas close to the protostar. In the scenario described here, the combined cooling by far-IR lines within the central spatial pixel is estimated to be 2 × 10-2 Lȯ...... in the outflow. In addition, [O i] emission is seen in low-velocity gas, assumed to be related to the envelope, and is also seen shifted up to 170 km s-1 in both the red- and blue-shifted jets. Envelope models are constructed based on previous observational constraints. They indicate that passive heating...... of a spherical envelope by the protostellar luminosity cannot explain the high-excitation molecular gas detected with PACS, including CO lines with upper levels at >2500 K above the ground state. Instead, warm CO and H2O emission is probably produced in the walls of an outflow-carved cavity in the envelope...

  14. Advanced sulfur control concepts for hot-gas desulfurization technology

    International Nuclear Information System (INIS)

    This research project examined the feasibility of a second generation high-temperature coal gas desulfurization process in which elemental sulfur is produced directly during the sorbent regeneration phase. Two concepts were evaluated experimentally. In the first, FeS was regenerated in a H2O-O2 mixture. Large fractions of the sulfur were liberated in elemental form when the H2O-O2 ratio was large. However, the mole percent of elemental sulfur in the product was always quite small (<<1%) and a process based on this concept was judged to be impractical because of the low temperature and high energy requirements associated with condensing the sulfur. The second concept involved desulfurization using CeO2 and regeneration of the sulfided sorbent, Ce2O2S, using SO2 to produce elemental sulfur directly. No significant side reactions were observed and the reaction was found to be quite rapid over the temperature range of 500C to 700C. Elemental sulfur concentrations (as S2) as large as 20 mol% were produced. Limitations associated with the cerium sorbent process are concentrated in the desulfurization phase. High temperature and highly reducing coal gas such as produced in the Shell gasification process are required if high sulfur removal efficiencies are to be achieved. For example, the equilibrium H2S concentration at 800C from a Shell gas in contact with CeO2 is about 300 ppmv, well above the allowable IGCC specification. In this case, a two-stage desulfurization process using CeO2 for bulk H2S removal following by a zinc sorbent polishing step would be required. Under appropriate conditions, however, CeO2 can be reduced to non-stoichiometric CeOn (n<2) which has significantly greater affinity for H2S. Pre-breakthrough H2S concentrations in the range of 1 ppmv to 5 ppmv were measured in sulfidation tests using CeOn at 700C in highly reducing gases, as measured by equilibrium O2 concentration, comparable to the Shell gas. Good sorbent durability was indicated in a

  15. ADVANCED SULFUR CONTROL CONCEPTS FOR HOT-GAS DESULFURIZATION TECHNOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    A. LOPEZ ORTIZ; D.P. HARRISON; F.R. GROVES; J.D. WHITE; S. ZHANG; W.-N. HUANG; Y. ZENG

    1998-10-31

    This research project examined the feasibility of a second generation high-temperature coal gas desulfurization process in which elemental sulfur is produced directly during the sorbent regeneration phase. Two concepts were evaluated experimentally. In the first, FeS was regenerated in a H2O-O2 mixture. Large fractions of the sulfur were liberated in elemental form when the H2O-O2 ratio was large. However, the mole percent of elemental sulfur in the product was always quite small (<<1%) and a process based on this concept was judged to be impractical because of the low temperature and high energy requirements associated with condensing the sulfur. The second concept involved desulfurization using CeO2 and regeneration of the sulfided sorbent, Ce2O2S, using SO2 to produce elemental sulfur directly. No significant side reactions were observed and the reaction was found to be quite rapid over the temperature range of 500°C to 700°C. Elemental sulfur concentrations (as S2) as large as 20 mol% were produced. Limitations associated with the cerium sorbent process are concentrated in the desulfurization phase. High temperature and highly reducing coal gas such as produced in the Shell gasification process are required if high sulfur removal efficiencies are to be achieved. For example, the equilibrium H2S concentration at 800°C from a Shell gas in contact with CeO2 is about 300 ppmv, well above the allowable IGCC specification. In this case, a two-stage desulfurization process using CeO2 for bulk H2S removal following by a zinc sorbent polishing step would be required. Under appropriate conditions, however, CeO2 can be reduced to non-stoichiometric CeOn (n<2) which has significantly greater affinity for H2S. Pre-breakthrough H2S concentrations in the range of 1 ppmv to 5 ppmv were measured in sulfidation tests using CeOn at 700°C in highly reducing gases, as measured by equilibrium O2 concentration, comparable to the Shell gas. Good sorbent durability was indicated in

  16. Analysis of catalytic gas products using electron energy-loss spectroscopy and residual gas analysis for operando transmission electron microscopy.

    Science.gov (United States)

    Miller, Benjamin K; Crozier, Peter A

    2014-06-01

    Operando transmission electron microscopy (TEM) of catalytic reactions requires that the gas composition inside the TEM be known during the in situ reaction. Two techniques for measuring gas composition inside the environmental TEM are described and compared here. First, electron energy-loss spectroscopy, both in the low-loss and core-loss regions of the spectrum was utilized. The data were quantified using a linear combination of reference spectra from individual gasses to fit a mixture spectrum. Mass spectrometry using a residual gas analyzer was also used to quantify the gas inside the environmental cell. Both electron energy-loss spectroscopy and residual gas analysis were applied simultaneously to a known 50/50 mixture of CO and CO2, so the results from the two techniques could be compared and evaluated. An operando TEM experiment was performed using a Ru catalyst supported on silica spheres and loaded into the TEM on a specially developed porous pellet TEM sample. Both techniques were used to monitor the conversion of CO to CO2 over the catalyst, while simultaneous atomic resolution imaging of the catalyst was performed. PMID:24815065

  17. Hot gas cleanup test facility for gasification and pressurized combustion project. Quarterly report, October--December 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    The objective of this project is to evaluate hot gas particle control technologies using coal-derived gas streams. This will entail the design, construction, installation, and use of a flexible test facility which can operate under realistic gasification and combustion conditions. The conceptual design of the facility was extended to include a within scope, phased expansion of the existing Hot Gas Cleanup Test Facility Cooperative Agreement to also address systems integration issues of hot particulate removal in advanced coal-based power generation systems. This expansion included the consideration of the following modules at the test facility in addition to the original Transport Reactor gas source and Hot Gas Cleanup Units: Carbonizer/pressurized circulating fluidized bed gas source; hot gas cleanup units to mate to all gas streams; combustion gas turbine; and fuel cell and associated gas treatment. This expansion to the Hot Gas Cleanup Test Facility is herein referred to as the Power Systems Development Facility (PSDF). The major emphasis during this reporting period was continuing the detailed design of the facility towards completion and integrating the balance-of-plant processes and particulate control devices (PCDs) into the structural and process designs. Substantial progress in construction activities was achieved during this quarter.

  18. Cleanable sintered metal filters in hot off-gas systems

    International Nuclear Information System (INIS)

    Filters with sintered metal elements, arranged as tube bundles with backflush air cleaning, are the equivalent of bag filters for high-temperature, harsh environments. They are virtually the only alternative for high-temperature off-gas systems where a renewable, highly efficient particle trap is required. Tests were conducted which show that the sintered metal elements installed in a filter system provide effective powder collection in high-temperature atmospheres over thousands of cleaning cycles. Such a sintered metal filter system is now installed on the experimental defense waste calciner at the Savannah River Laboratory. The experimental results included in this paper were used as the basis for its design

  19. Phi meson propagation in a hot hadronic gas

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez-Ruso, Luis; Koch, Volker

    2002-02-20

    The Hidden Local Symmetry Lagrangian is used to study the interactions of phi mesons with other pseudoscalar and vector mesons in a hadronic gas at finite temperature. We have found a significantly small phi mean free path (less than 2.4 fm at T > 170 MeV) due to large collision rates with rho mesons, kaons and predominantly K* in spite of their heavy mass. This implies that phi mesons produced after hadronization in relativistic heavy ion collisions will not leave the hadronic system without scattering. The effect of these interactions on the time evolution of the phi density in the expanding hadronic fireball is investigated.

  20. Phi meson propagation in a hot hadronic gas

    CERN Document Server

    Alvarez-Ruso, L

    2002-01-01

    The Hidden Local Symmetry Lagrangian is used to study the interactions of phi mesons with other pseudoscalar and vector mesons in a hadronic gas at finite temperature. We have found a significantly small phi mean free path (less than 2.4 fm at T > 170 MeV) due to large collision rates with rho mesons, kaons and predominantly K* in spite of their heavy mass. This implies that phi mesons produced after hadronization in relativistic heavy ion collisions will not leave the hadronic system without scattering. The effect of these interactions on the time evolution of the phi density in the expanding hadronic fireball is investigated.

  1. Embryo impacts and gas giant mergers II: Diversity of Hot Jupiters' internal structure

    CERN Document Server

    Liu, Shang-Fei; Lin, D N C; Li, Shu-Lin

    2014-01-01

    We consider the origin of compact, short-period, Jupiter-mass planets. We propose that their diverse structure is caused by giant impacts of embryos and super-Earths or mergers with other gas giants during the formation and evolution of these hot Jupiters. Through a series of numerical simulations, we show that typical head-on collisions generally lead to total coalescence of impinging gas giants. Although extremely energetic collisions can disintegrate the envelope of gas giants, these events seldom occur. During oblique and moderately energetic collisions, the merger products retain higher fraction of the colliders' cores than their envelopes. They can also deposit considerable amount of spin angular momentum to the gas giants and desynchronize their spins from their orbital mean motion. We find that the oblateness of gas giants can be used to infer the impact history. Subsequent dissipation of stellar tide inside the planets' envelope can lead to runaway inflation and potentially a substantial loss of gas ...

  2. Design and Experimentation with Sandwich Microstructure for Catalytic Combustion-Type Gas Sensors

    Directory of Open Access Journals (Sweden)

    Jun-Tao Gu

    2014-03-01

    Full Text Available The traditional handmade catalytic combustion gas sensor has some problems such as a pairing difficulty, poor consistency, high power consumption, and not being interchangeable. To address these issues, integrated double catalytic combustion of alcohol gas sensor was designed and manufactured using silicon micro-electro-mechanical systems (MEMS technology. The temperature field of the sensor is analyzed using the ANSYS finite element analysis method. In this work, the silicon oxide-PECVD-oxidation technique is used to manufacture a SiO2-Si3N2-SiO2 microstructure carrier with a sandwich structure, while wet etching silicon is used to form a beam structure to reduce the heat consumption. Thin-film technology is adopted to manufacture the platinum-film sensitive resistance. Nano Al2O3-ZrO-ThO is coated to format the sensor carrier, and the sensitive unit is dipped in a Pt-Pd catalyst solution to form the catalytic sensitive bridge arm. Meanwhile the uncoated catalyst carrier is considered as the reference unit, realizing an integrated chip based on a micro double bridge and forming sensors. The lines of the Pt thin-film resistance have been observed with an electronic microscope. The compensation of the sensitive material carriers and compensation materials have been analyzed using an energy spectrum. The results show that the alcohol sensor can detect a volume fraction between 0 and 4,500 × 10−6 and has good linear output characteristic. The temperature ranges from −20 to +40 °C. The humidity ranges from 30% to 85% RH. The zero output of the sensor is less than ±2.0% FS. The power consumption is ≤0.2 W, and both the response and recovery time are approximately 20 s.

  3. Design and experimentation with sandwich microstructure for catalytic combustion-type gas sensors.

    Science.gov (United States)

    Gu, Jun-Tao; Zhang, Yong-De; Jiang, Jin-Gang

    2014-01-01

    The traditional handmade catalytic combustion gas sensor has some problems such as a pairing difficulty, poor consistency, high power consumption, and not being interchangeable. To address these issues, integrated double catalytic combustion of alcohol gas sensor was designed and manufactured using silicon micro-electro-mechanical systems (MEMS) technology. The temperature field of the sensor is analyzed using the ANSYS finite element analysis method. In this work, the silicon oxide-PECVD-oxidation technique is used to manufacture a SiO2-Si3N2-SiO2 microstructure carrier with a sandwich structure, while wet etching silicon is used to form a beam structure to reduce the heat consumption. Thin-film technology is adopted to manufacture the platinum-film sensitive resistance. Nano Al2O3-ZrO-ThO is coated to format the sensor carrier, and the sensitive unit is dipped in a Pt-Pd catalyst solution to form the catalytic sensitive bridge arm. Meanwhile the uncoated catalyst carrier is considered as the reference unit, realizing an integrated chip based on a micro double bridge and forming sensors. The lines of the Pt thin-film resistance have been observed with an electronic microscope. The compensation of the sensitive material carriers and compensation materials have been analyzed using an energy spectrum. The results show that the alcohol sensor can detect a volume fraction between 0 and 4,500 × 10(-6) and has good linear output characteristic. The temperature ranges from -20 to +40 °C. The humidity ranges from 30% to 85% RH. The zero output of the sensor is less than ±2.0% FS. The power consumption is ≤0.2 W, and both the response and recovery time are approximately 20 s. PMID:24625742

  4. Electric Conductivity of a hot hadron gas from a kinetic approach

    CERN Document Server

    Greif, Moritz; Denicol, Gabriel S

    2016-01-01

    We calculate the electric conductivity of a gas of relativistic particles with isotropic cross sections using the Boltzmann equation as the starting point. Our analyses is restricted to elastic collisions. We show the perfect agreement with previously published numerical results for a massless quark- gluon plasma, and give results for the electric conductivity of an interacting hadron gas, employing realistic resonance cross sections. These results for the electric conductivity of a hot hadron gas, as created in (ultra-)relativistic heavy-ion collisions, are of rich phenomenological as well as theoretical interest and can be compared to, e.g., lattice quantum field theory calculations.

  5. Novel Gas Barrier SiOC Coating to PET Bottles through a Hot Wire CVD Method

    Directory of Open Access Journals (Sweden)

    Masaki Nakaya

    2016-01-01

    Full Text Available In an attempt to enhance the gas barrier enhancement of plastic containers such as poly(ethylene terephthalate bottles, a novel method was found using a hot wire CVD technique, where tantalum wire is heated and exposed to a gas flow of vinyl silane. The resultant SiOC thin film was confirmed to characteristically contain Si-Si bonds in its surface and demonstrate a remarkably and highly practical decrease of the permeation of various gas through poly(ethylene terephthalate bottles.

  6. Investigation of a catalytic gas generator for the Space Shuttle APU. [hydrazine Auxiliary Propulsion Unit

    Science.gov (United States)

    Emmons, D. L.; Huxtable, D. D.; Blevins, D. R.

    1974-01-01

    An investigation was conducted to establish the capability of a monopropellant hydrazine catalytic gas generator to meet the requirements specified for the Space Shuttle APU. Detailed analytical and experimental studies were conducted on potential problem areas including long-term nitriding effects on materials, design variables affecting catalyst life, vehicle vibration effects, and catalyst oxidation/contamination. A full-scale gas generator, designed to operate at a chamber pressure of 750 psia and a flow rate of 0.36 lbm/sec, was fabricated and subjected to three separate life test series. The objective of the first test series was to demonstrate the capability of the gas generator to successfully complete 20 simulated Space Shuttle missions in steady-state operation. The gas generator was then refurbished and subjected to a second series of tests to demonstrate the pulse-mode capability of the gas generator during 20 simulated missions. The third series of tests was conducted with a refurbished reactor to further demonstrate pulse-mode capability with a modified catalyst bed.

  7. Determining the Origins and Impact of Hot Gas in the Milky Way

    Science.gov (United States)

    Miller, Matthew J.; Bregman, Joel N.; Hodges-Kluck, Edmund J.

    2016-01-01

    The Milky Way's circumgalactic medium contains million degree gas that is volume-filling on ≥10 kpc scales based on X-ray emission from the ROSAT All-Sky Survey, detections of OVII Kα (λ=21.602 Å) absorption lines at z~0 in AGN spectra, ubiquitous detections of OVII-OVIII emission lines in ~1,000 blank-sky spectra, and the discovery of the ~10 kpc outflow from the Galactic center known as the Fermi bubbles. Analyses on the line strengths in individual or small samples of sight lines (dissertation, I constrain the global hot gas density structure by comparing the largest samples of OVII equivalent width measurements and OVII-OVIII line intensities with model line strengths from parametric density models. I find that a spherical profile with n ∝ r-3/2 extending to the Milky Way's virial radius results in model line strenghts that are most consistent with how the observed line strengths vary across the sky. These results imply a hot gas mass between 2-5 x 1010 M⊙ within 250 kpc (≤ 50% of the Galactic missing baryons), a hot gas metallicity of Z ≥ .3 Z⊙, and that most of the hot gas formed as shock-heated material during the Milky Way's formation. For the Fermi bubbles, the line intensities and ratios suggest they contain hotter gas than the surrounding medium (> 2 x 106 K) and densities between 10-4-10-3 cm-3. This implies the bubbles are over-pressurized and expanding into the surrounding halo, potentially heating and displacing the ambient CGM.

  8. Selective catalytic oxidation of ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Leppaelahti, J.; Koljonen, T. [VTT Energy, Espoo (Finland)

    1996-12-31

    In the combustion of fossil fuels, the principal source of nitrogen oxides is nitrogen bound in the fuel structure. In gasification, a large part of fuel nitrogen forms NH{sub 3}, which may form nitrogen oxides during gas combustion. If NH{sub 3} and other nitrogen species could be removed from hot gas, the NO emission could be considerably reduced. However, relatively little attention has been paid to finding new means of removing nitrogen compounds from the hot gasification gas. The possibility of selectively oxidizing NH{sub 3} to N{sub 2} in the hot gasification has been studied at VTT Energy. The largest NH{sub 3} reductions have been achieved by catalytic oxidation on aluminium oxides. (author) (4 refs.)

  9. Application of CFCC technology to hot gas filtration applications

    Energy Technology Data Exchange (ETDEWEB)

    Richlen, S.

    1995-06-01

    Discussion will feature high temperature filter development under the DOE`s Office of Industrial Technologies Continuous Fiber Ceramic Composite (CFCC) Program. Within the CFCC Program there are four industry projects and a national laboratory technology support project. Atlantic Research, Babcock & Wilcox, DuPont Lanxide Composites, and Textron are developing processing methods to produce CFCC Components with various types of matrices and composites, along with the manufacturing methods to produce industrial components, including high temperature gas filters. The Oak Ridge National Laboratory is leading a National Laboratory/University effort to increase knowledge of such generic and supportive technology areas as environmental degradation, measurement of mechanical properties, long-term performance, thermal shock and thermal cycling, creep and fatigue, and non-destructive characterization. Tasks include composite design, materials characterization, test methods, and performance-related phenomena, that will support the high temperature filter activities of industry and government.

  10. Increased capability gas generator for Space Shuttle APU. Development/hot restart test report

    Science.gov (United States)

    1980-01-01

    The design, fabrication, and testing of an increased capability gas generator for use in space shuttles are described. Results show an unlimited hot restart capability in the range of feed pressures from 400 psi to 80 psi. Effects of vacuum on hot restart were not addressed, and only beginning-of-life bed conditions were tested. No starts with bubbles were performed. A minimum expected life of 35 hours or more is projected, and the design will maintain a surface temperature of 350 F or more.

  11. Embryo impacts and gas giant mergers - II. Diversity of hot Jupiters' internal structure

    Science.gov (United States)

    Liu, Shang-Fei; Agnor, Craig B.; Lin, D. N. C.; Li, Shu-Lin

    2015-01-01

    We consider the origin of compact, short-period, Jupiter-mass planets. We propose that their diverse structure is caused by giant impacts of embryos and super-Earths or mergers with other gas giants during the formation and evolution of these hot Jupiters. Through a series of numerical simulations, we show that typical head-on collisions generally lead to total coalescence of impinging gas giants. Although extremely energetic collisions can disintegrate the envelope of gas giants, these events seldom occur. During oblique and moderately energetic collisions, the merger products retain higher fraction of the colliders' cores than their envelopes. They can also deposit considerable amount of spin angular momentum to the gas giants and desynchronize their spins from their orbital mean motion. We find that the oblateness of gas giants can be used to infer the impact history. Subsequent dissipation of stellar tide inside the planets' envelope can lead to runaway inflation and potentially a substantial loss of gas through Roche lobe overflow. The impact of super-Earths on parabolic orbits can also enlarge gas giant planets' envelope and elevates their tidal dissipation rate over ˜100 Myr time scale. Since giant impacts occur stochastically with a range of impactor sizes and energies, their diverse outcomes may account for the dispersion in the mass-radius relationship of hot Jupiters.

  12. CRADA opportunities with METC`s gasification and hot gas cleanup facility

    Energy Technology Data Exchange (ETDEWEB)

    Galloway, E.N.; Rockey, J.M.; Tucker, M.S.

    1995-06-01

    Opportunities exist for Cooperative Research and Development Agreements (CRADA) at the Morgantown Energy Technology Center (METC) to support commercialization of IGCC power systems. METC operates an integrated gasifier and hot gas cleanup facility for the development of gasification and hot gas cleanup technologies. The objective of our program is to gather performance data on gasifier operation, particulate removal, desulfurization and regeneration technologies. Additionally, slip streams are provided for developing various technologies such as; alkali monitoring, particulate measuring, chloride removal, and contaminate recovery processes. METC`s 10-inch diameter air blown Fluid Bed Gasifier (FBG) provides 300 lb/hr of coal gas at 1100{degrees}F and 425 psig. The particulate laden gas is transported to METC`s Modular Gas Cleanup Rig (MGCR). The gas pressure is reduced to 285 psig before being fed into a candle filter vessel. The candle filter vessel houses four candle filters and multiple test coupons. The particulate free gas is then desulfurized in a sorbent reactor. Starting in 1996 the MGCR system will be able to regenerate the sorbent in the same vessel.

  13. PARTICLE TRANSPORTATION AND DEPOSITION IN HOT GAS FILTER VESSELS - A COMPUTATIONAL AND EXPERIMENTAL MODELING APPROACH

    Energy Technology Data Exchange (ETDEWEB)

    Goodarz Ahmadi

    2002-07-01

    In this project, a computational modeling approach for analyzing flow and ash transport and deposition in filter vessels was developed. An Eulerian-Lagrangian formulation for studying hot-gas filtration process was established. The approach uses an Eulerian analysis of gas flows in the filter vessel, and makes use of the Lagrangian trajectory analysis for the particle transport and deposition. Particular attention was given to the Siemens-Westinghouse filter vessel at Power System Development Facility in Wilsonville in Alabama. Details of hot-gas flow in this tangential flow filter vessel are evaluated. The simulation results show that the rapidly rotation flow in the spacing between the shroud and the vessel refractory acts as cyclone that leads to the removal of a large fraction of the larger particles from the gas stream. Several alternate designs for the filter vessel are considered. These include a vessel with a short shroud, a filter vessel with no shroud and a vessel with a deflector plate. The hot-gas flow and particle transport and deposition in various vessels are evaluated. The deposition patterns in various vessels are compared. It is shown that certain filter vessel designs allow for the large particles to remain suspended in the gas stream and to deposit on the filters. The presence of the larger particles in the filter cake leads to lower mechanical strength thus allowing for the back-pulse process to more easily remove the filter cake. A laboratory-scale filter vessel for testing the cold flow condition was designed and fabricated. A laser-based flow visualization technique is used and the gas flow condition in the laboratory-scale vessel was experimental studied. A computer model for the experimental vessel was also developed and the gas flow and particle transport patterns are evaluated.

  14. Solar heating, cooling and domestic hot water system installed at Columbia Gas System Service Corporation, Columbus, Ohio

    Science.gov (United States)

    1980-11-01

    The solar energy system installed in the building has 2,978 sq ft of single axis tracking, concentrating collectors and provides solar energy for space heating, space cooling and domestic hot water. A 1,200,000 Btu/hour water tube gas boiler provides hot water for space heating. Space cooling is provided by a 100 ton hot water fired absorption chiller. Domestic hot water heating is provided by a 50 gallon natural gas domestic storage water heater. Extracts from the site files, specification references, drawings, installation, operation and maintenance instructions are included.

  15. Solar heating, cooling and domestic hot water system installed at Columbia Gas System Service Corporation, Columbus, Ohio

    Science.gov (United States)

    1980-01-01

    The solar energy system installed in the building has 2,978 sq ft of single axis tracking, concentrating collectors and provides solar energy for space heating, space cooling and domestic hot water. A 1,200,000 Btu/hour water tube gas boiler provides hot water for space heating. Space cooling is provided by a 100 ton hot water fired absorption chiller. Domestic hot water heating is provided by a 50 gallon natural gas domestic storage water heater. Extracts from the site files, specification references, drawings, installation, operation and maintenance instructions are included.

  16. Kinetic and Phase Behaviors of Catalytic Cracking Dry Gas Hydrate in Water-in-Oil Emulsion

    Institute of Scientific and Technical Information of China (English)

    MA Qinglan; HUANG Qiang; CHEN Guangjin; WANG Xiulin; SUN Changyu; YANG Lanying

    2013-01-01

    The systematic experimental studies were performed on the hydrate formation kinetics and gas-hydrate equilibrium for a simulated catalytic cracking gas in the water-in-oil emulsion.The effect of temperature,pressure and initial gas-liquid ratio on the hydrate formation was studied,respectively.The data were obtained at pressures ranging from 3.5 to 5 MPa and temperatures from 274.15 to 277.15 K.The results showed that hydrogen and methane can be separated from the C2+ fraction by forming hydrate at around 273.15 K which is much higher temperature than that of the cryogenic separation method,and the hydrate formation rate can be enhanced in the water-in-oil emulsion compared to pure water.The experiments provided the basic data for designing the industrial process,and setting the suitable operational conditions.The measured data of gas-hydrate equilibria were compared with the predictions by using the Chen-Guo hydrate thermodynamic model.

  17. Supernova Feedback and the Hot Gas Filling Fraction of the Interstellar Medium

    CERN Document Server

    Li, Miao; Cen, Renyue; Bryan, Greg L; Naab, Thorsten

    2015-01-01

    Supernovae are the most energetic among stellar feedback processes, and are crucial for regulating the interstellar medium (ISM) and launching galactic winds. We explore how supernova remnants (SNRs) create a multiphase medium by performing high resolution, 3D hydrodynamical simulations at various SN rates, $S$, and ISM average densities, $n$. We find that the evolution of a SNR in a self-consistently generated three-phase ISM is qualitatively different from that in a uniform or a two-phase warm/cold medium. By traveling faster and further in the cooling-inefficient hot phase, the spatial-temporal domain of a SNR is enlarged by $>10^{2.5}$ in a hot-dominated multiphase medium (HDMM) compared to the uniform case. We then examine the resultant ISM as we vary $n$ and $S$, finding that a steady state can only be achieved when the hot gas volume fraction \\fvh $\\lesssim 0.6\\pm 0.1$. Above that, overlapping SNRs render connecting topology of the hot gas, and such a HDMM is subjected to thermal runaway with growing p...

  18. Dynamic and thermal behavior of hot gas bubbles discharged into water

    International Nuclear Information System (INIS)

    A postulated severe accident of a nuclear power plant can result in airborne radioactive fission products which are discharged into a water pool. The dynamic and thermal behavior of hot gas discharge into a water pool plays a major role in the scrubbing removal of fission products from the gas, thereby significantly reducing the radiation release from such a postulated accident. This paper employs both available literature and recent data, analyses and correlations to help quantify several aspects of bubble behavior which are important to scrubbing. These include the stable bubble size and rise velocity, large bubble detachment size from vents and breakup distance, and hot bubble size variation caused by heat transfer and water vaporization. (orig.)

  19. A simple, hot N2-gas TL reader incorporating a post-irradiation annealing facility

    International Nuclear Information System (INIS)

    A simple 'do-it-yourself' TL reader is outlined. It is based on a hot nitrogen gas heating technique that has been routinely used at Risoe for several years and thus intensively investigated. A description is given of the complete TL read-out system including electronic circuit diagrams of the most vital parts. Results are presented to demonstrate the features of the system. (Auth.)

  20. Mapping the Physical Properties of Cosmic Hot Gas with Hyper-spectral Imaging

    CERN Document Server

    O'Dwyer, M; Raychaudhuri, S; Dwyer, Mark O'; Ponman, Trevor; Raychaudhury, Ela Claridge & Somak

    2005-01-01

    A novel inversion technique is proposed to compute parametric maps showing the temperature, density and chemical composition of cosmic hot gas from X-ray hyper-spectral images. The parameters are recovered by constructing a unique non-linear mapping derived by combining a physics-based modelling of the X-ray spectrum with the selection of optimal bandpass filters. Preliminary results and analysis are presented.

  1. The role of catalytic nanoparticle pretreatment on the growth of vertically aligned carbon nanotubes by hot-filament chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki-Hwan; Gohier, Aurélien; Bourée, Jean Eric; Châtelet, Marc; Cojocaru, Costel-Sorin, E-mail: costel-sorin.cojocaru@polytechnique.edu

    2015-01-30

    The effect of atomic hydrogen assisted pre-treatment on the growth of vertically aligned carbon nanotubes using hot-filament chemical vapor deposition was investigated. Iron nanoparticle catalysts were formed on an aluminum oxide support layer by spraying of iron chloride salt solutions as catalyst precursor. It is found that pre-treatment time and process temperature tune the density as well as the shape and the structure of the grown carbon nanotubes. An optimum pre-treatment time can be found for the growth of long and well aligned carbon nanotubes, densely packed to each other. To provide insight on this behavior, the iron catalytic nanoparticles formed after the atomic hydrogen assisted pre-treatment were analyzed by atomic force microscopy. The relations between the size and the density of the as-formed catalyst and the as-grown carbon nanotube's structure and density are discussed. - Highlights: • Effect of the atomic hydrogen assisted pre-treatment on the growth of VACNT using hot-filament CVD. • Pre-treatment time and process temperature tune the density, the shape and the structure of the CNTs. • Correlations between size and density of the as-formed catalyst and the CNT’s structure and density. • Carbon nanotubes synthesized at low temperature down to 500 °C using spayed iron chloride salts. • Density of the CNT carpet adjusted by catalytic nanoparticle engineering.

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

    Science.gov (United States)

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

    2014-02-28

    Using a sol-gel method, SmMeOx/MCM-41 or SBA-15 (Me=Fe, Co and Zn) and corresponding unsupported sorbents were prepared. The desulfurization performance of these sorbents was evaluated over a fixed-bed reactor and the effects of reaction temperature, feed and sorbent composition on desulfurization performance were studied. Samarium-based sorbents used to remove H2S from hot coal gas were reported for the first time. The results of successive sulfidation/regeneration cycles revealed that SmFeO3/SBA-15 sorbent was suitable for desulfurization of hot coal gas in the chemical industry. The formation of elemental sulfur during both sulfidation and regeneration processes depended strongly on the catalytic action of Sm2O2S species, which was confirmed for the first time via high sensitive time of flight mass spectrometer (TOF-MS) using 6%vol(18)O2/Ar regeneration gas and can reduce markedly procedural complexity. The sorbents were characterized using N2-adsorption, high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), temperature-programmed reduction of H2 (H2-TPR), thermogravimetry (TG) and time-of-flight mass spectrometry (TOF-MS) techniques. PMID:24462892

  3. Hot waste-to-energy flue gas treatment using an integrated fluidised bed reactor

    International Nuclear Information System (INIS)

    This paper describes an innovative process to increase superheated steam temperatures in waste-to-energy (WTE) plants. This solution is mainly characterised by a fluidised bed reactor in which hot flue gas is treated both chemically and mechanically. This approach, together with gas recirculation, increases the energy conversion efficiency, and raises the superheated steam temperature without decreasing the useful life of the superheater. This paper presents new experimental data obtained from the test facility installed at the Hera S.p.A. WTE plant in Forli, Italy; discusses changes that can be implemented to increase the duration of experimental testing; offers suggestions for the design of an industrial solution

  4. GARROTXA cosmological simulations of Milky Way like galaxies - I. Hot gas and the missing baryons

    CERN Document Server

    Roca-Fàbrega, Santi; Colín, Pedro; Figueras, Francesca; Krongold, Yair; Velázquez, Héctor

    2015-01-01

    We introduce a new set of simulations of a Milky Way like galaxy using the AMR code ART + hydrodynamics in a $\\Lambda$CDM cosmogony. The simulation series is named GARROTXA and follow the formation of a late type galaxy from z=60 with a final virial mass of \\sim$7.4$\\times$10$^{11}$M$_{\\odot}$. This system has no major mergers since z=3 and at z=0 becomes a disk late-type spiral galaxy. Several of its large scale properties fall inside recent observational limits of our Galaxy, like the rotation curve shape, the presence of a stellar bar and flare, and a gaseous disk warp, as well as the stellar and baryonic mass. Here, as a first scientific exploitation of the model we study the total amount and spatial distribution of hot X-ray luminous gas. We do not observe in our models a significant presence of a hot gas thick disk as has been recently discussed in observational studies. The analysis of hot gas mock observations (column density and emission measure) revealed that commonly used hypothesis assumed to deri...

  5. Redistributing hot gas around galaxies: do cool clouds signal a solution to the overcooling problem?

    CERN Document Server

    Kaufmann, Tobias; Maller, Ariyeh H; Fang, Taotao; Wadsley, James

    2008-01-01

    We present a pair of high-resolution smoothed particle hydrodynamics (SPH) simulations that explore the evolution and cooling behavior of hot gas around Milky-Way size galaxies. The simulations contain the same total baryonic mass and are identical other than their initial gas density distributions. The first is initialised with a low entropy hot gas halo that traces the cuspy profile of the dark matter, and the second is initialised with a high-entropy hot halo with a cored density profile as might be expected in models with pre-heating feedback. Galaxy formation proceeds in dramatically different fashion depending on the initial setup. While the low-entropy halo cools rapidly, primarily from the central region, the high-entropy halo is quasi-stable for ~4 Gyr and eventually cools via the fragmentation and infall of clouds from ~100 kpc distances. The low-entropy halo's X-ray surface brightness is ~100 times brighter than current limits and the resultant disc galaxy contains more than half of the system's ba...

  6. A Technical and Economical Evaluation of CO2 Capture from Fluidized Catalytic Cracking (FCC Flue Gas

    Directory of Open Access Journals (Sweden)

    Digne Romina

    2014-11-01

    Full Text Available Environmental issues, related to greenhouse gas and among them CO2, are becoming short term challenges. Pressure on industries and therefore on refining to limit and manage CO2 emissions will be reinforced in next few years. Refining industry is responsible for about 2.7% of global CO2 emissions. Fluidized Catalytic Cracking unit (FCC, one of the main process in refining, represents by itself 20% of the refinery CO2 emissions. As FCC unit is present in half of the refining schemes, it is challenging to find technologies to manage its emissions. Based on an industrial case, the aims of the presented work are to determine if amine technology HiCapt+, developed for power plant, might be a relevant solution to manage FCC CO2 emissions and to evaluate the additional cost to be supported by refiners.

  7. Control of gaseous pollutants emission with EGR (exhaust gas recirculation) and catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Porto, Fernando Silva de Araujo [Faculdade de Engenharia Quimica de Lorena (FAENQUIL), SP (Brazil); Mann, Jens; Ueberschaer, Dietmar [Fachhochschule Darmstadt (Germany). Fachbereich Maschinenbau; Balestieri, Jose Antonio Perrella; Nascimento, Nazem [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia]. E-mail: ftilor@eu.ansp.br; perrella@feg.unesp.br; nazem@feg.unesp.br

    1997-07-01

    Study of gaseous pollutant emission from engine tests simulating real work conditions, using spark point manually controlled and exhaust gas recirculation in diverse proportion levels. The objective of this present work is to re-examine the potential of the EGR conception, a well-known method of combustion control, employed together electronic fuel injection and three-way catalytic converter closed-loop control at a spark ignition engine, verifying the performance characteristics and technical availability of this conception to improve pollution control and fuel economy. The pollutant emissions under operational conditions were analyzed and compared with the expected by concerning theory and real tests performed by EGR equipped engines by factory. (author)

  8. In bed and downstream hot gas desulphurization during solid fuel gasification: A review

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Xiangmei; de Jong, Wiebren; Pal, Ranadeep; Verkooijen, Adrian H.M. [Faculty of Mechanical, Maritime and Materials Engineering, Process and Energy Department, Energy Technology Section, Delft University of Technology, Leeghwaterstraat 44, 2628 CA, Delft (Netherlands)

    2010-08-15

    Syngas produced by gasification process of biomass fuels is an environmental friendly alternative to conventional petrochemical fuels for the production of electricity, hydrogen, synthetic transportation biofuels and other chemicals. However, the advanced utilization of syngas is significantly limited due to the contaminants which can seriously deactivate the catalysts used for downstream reaction such as steam reforming methane, Fischer-Tropsch synthesis and corrosion of downstream equipments such as a gas turbine. Among the contaminants, sulphur compounds produced in the gasification process, which are mainly H{sub 2}S with small amounts of COS, CS{sub 2} and thiophenes depending on process conditions, must be removed. For biomass feedstock advances are required in the cleanup technologies and processes to upgrade the raw product gas with minimal impact on the overall process efficiency. Hot gas desulphurization (HGD) can improve the overall thermal efficiency due to the elimination of fuel gas cooling and associated heat exchangers. With this aim, the present review paper highlights currently developed methods used for desulphurization of hot gas produced from gasification process of solid fuels. The methods presented here are for both in situ and downstream sulphur capture. Also, the attention is paid to the regeneration of the used materials. In situ sulphur capture is mainly done by using calcium-based sorbents such as limestone and dolomite, whereas downstream sulphur capture is mainly focused on the use of regenerable single, mixed, and supported metal oxides. A comparison is indicated at the end to show the sulphur loading of various materials. (author)

  9. Non-catalytic recuperative reformer

    Energy Technology Data Exchange (ETDEWEB)

    Khinkis, Mark J.; Kozlov, Aleksandr P.; Kurek, Harry

    2015-12-22

    A non-catalytic recuperative reformer has a flue gas flow path for conducting hot flue gas from a thermal process and a reforming mixture flow path for conducting a reforming mixture. At least a portion of the reforming mixture flow path is embedded in the flue gas flow path to permit heat transfer from the hot flue gas to the reforming mixture. The reforming mixture flow path contains substantially no material commonly used as a catalyst for reforming hydrocarbon fuel (e.g., nickel oxide, platinum group elements or rhenium), but instead the reforming mixture is reformed into a higher calorific fuel via reactions due to the heat transfer and residence time. In a preferred embodiment, extended surfaces of metal material such as stainless steel or metal alloy that are high in nickel content are included within at least a portion of the reforming mixture flow path.

  10. Evaluation of SI engine exhaust gas emissions upstream and downstream of the catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Silva, C.M.; Costa, M.; Farias, T.L. [Mechanical Engineering Department, Instituto Superior Tecnico, Technical University of Lisbon, Avenida Rovisco Pais, 1049-001 Lisbon (Portugal); Santos, H. [Escola Superior de Tecnologia e Gestao, Instituto Politecnico de Leiria, Leiria (Portugal)

    2006-11-15

    The conversion efficiency of a catalytic converter, mounted on a vehicle equipped with a 2.8l spark ignition engine, was evaluated under steady state operating conditions. The inlet and outlet chemical species concentration, temperature and air fuel ratio (A/F) were measured as a function of the brake mean effective pressure (BMEP) and engine speed (rpm). Oil temperature, coolant temperature, brake power and spark advance were also monitored. In parallel, a mathematical model for the catalytic converter has been developed. The main inputs of the model are the temperature, flow rate, chemical species mass flow and local A/F ratio as measured at the catalyst inlet section. The main conclusions are: (i) the exhaust gas and substrate wall temperatures at the catalyst outlet increase with BMEP and rpm; (ii) the HC conversion efficiency increases with the value of BMEP up to a maximum beyond which it decreases; (iii) the CO conversion efficiencies typically increase with BMEP; (iv) the NO{sub x} conversion efficiency remains nearly constant regardless of BMEP and rpm; (v) except for idle, the NO{sub x} conversion efficiency is typically the highest, followed in turn by the CO and HC conversion efficiencies; (vi) conversion efficiencies are lower for idle conditions, which can be a problem under traffic conditions where idle is a common situation; (vii) regardless of rpm and load, for the same flow rate the conversion efficiency is about the same; (viii) the model predictions slightly over estimate the exhaust gas temperature data at the catalyst outlet section with the observed differences decreasing with BMEP and engine speed; (ix) in general, the model predictions of the conversion efficiencies are satisfactory. (author)

  11. Reaction pathways for catalytic gas-phase oxidation of glycerol over mixed metal oxides

    Energy Technology Data Exchange (ETDEWEB)

    Suprun, W.; Glaeser, R.; Papp, H. [Leipzig Univ. (Germany). Inst. of Chemical Technology

    2011-07-01

    Glycerol as a main by-product from bio-diesel manufacture is a cheap raw material with large potential for chemical or biochemical transformations to value-added C3-chemicals. One possible way of glycerol utilization involves its catalytic oxidation to acrylic acid as an alternative to petrochemical routes. However, this catalytic conversion exhibits various problems such as harsh reaction conditions, severe catalyst coking and large amounts of undesired by-products. In this study, the reaction pathways for gas-phase conversion of glycerol over transition metal oxides (Mo, V und W) supported on TiO{sub 2} and SiO{sub 2} were investigated by two methods: (i) steady state experiments of glycerol oxidation and possible reactions intermediates, i.e., acrolein, 3-hydroxy propionaldehyde and acetaldehyde, and (ii) temperature-programmed surface reaction (TPSR) studies of glycerol conversion in the presence and in the absence of gas-phase oxygen. It is shown that the supported W-, V and Mo-oxides possess an ability to catalyze the oxidation of glycerol to acrylic acid. These investigations allowed us to gain a deeper insight into the reaction mechanism. Thus, based on the obtained results, three possible reactions pathways for the selective oxidation of glycerol to acrylic acid on the transition metal-containing catalysts are proposed. The major pathways in presence of molecular oxygen are a fast successive destructive oxidation of glycerol to CO{sub x} and the dehydration of glycerol to acrolein which is a rate-limiting step. (orig.)

  12. 18O2 label mechanism of sulfur generation and characterization in properties over mesoporous Sm-based sorbents for hot coal gas desulfurization

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Formation of sulfur originated from catalytic action of samarium oxysulfide. • Mechanism of sulfur desorption was first confirmed via time of flight MS. • Utilization of mesoporous Sm-based sorbents was favorable for diffusion of H2S. • Stability of Sm-based sorbent correlated with reasonable regeneration procedure. - Abstract: Using a sol–gel method, SmMeOx/MCM-41 or SBA-15 (Me = Fe, Co and Zn) and corresponding unsupported sorbents were prepared. The desulfurization performance of these sorbents was evaluated over a fixed-bed reactor and the effects of reaction temperature, feed and sorbent composition on desulfurization performance were studied. Samarium-based sorbents used to remove H2S from hot coal gas were reported for the first time. The results of successive sulfidation/regeneration cycles revealed that SmFeO3/SBA-15 sorbent was suitable for desulfurization of hot coal gas in the chemical industry. The formation of elemental sulfur during both sulfidation and regeneration processes depended strongly on the catalytic action of Sm2O2S species, which was confirmed for the first time via high sensitive time of flight mass spectrometer (TOF-MS) using 6%vol18O2/Ar regeneration gas and can reduce markedly procedural complexity. The sorbents were characterized using N2-adsorption, high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), temperature-programmed reduction of H2 (H2-TPR), thermogravimetry (TG) and time-of-flight mass spectrometry (TOF-MS) techniques

  13. {sup 18}O{sub 2} label mechanism of sulfur generation and characterization in properties over mesoporous Sm-based sorbents for hot coal gas desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Liu, B.S., E-mail: bingsiliu@tju.edu.cn [Department of Chemistry, School of Science, Tianjin University, and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072 (China); Wan, Z.Y.; Wang, F.; Zhan, Y.P. [Department of Chemistry, School of Science, Tianjin University, and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072 (China); Tian, M.; Cheung, A.S.C. [Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong (China)

    2014-02-01

    Graphical abstract: - Highlights: • Formation of sulfur originated from catalytic action of samarium oxysulfide. • Mechanism of sulfur desorption was first confirmed via time of flight MS. • Utilization of mesoporous Sm-based sorbents was favorable for diffusion of H{sub 2}S. • Stability of Sm-based sorbent correlated with reasonable regeneration procedure. - Abstract: Using a sol–gel method, SmMeO{sub x}/MCM-41 or SBA-15 (Me = Fe, Co and Zn) and corresponding unsupported sorbents were prepared. The desulfurization performance of these sorbents was evaluated over a fixed-bed reactor and the effects of reaction temperature, feed and sorbent composition on desulfurization performance were studied. Samarium-based sorbents used to remove H{sub 2}S from hot coal gas were reported for the first time. The results of successive sulfidation/regeneration cycles revealed that SmFeO{sub 3}/SBA-15 sorbent was suitable for desulfurization of hot coal gas in the chemical industry. The formation of elemental sulfur during both sulfidation and regeneration processes depended strongly on the catalytic action of Sm{sub 2}O{sub 2}S species, which was confirmed for the first time via high sensitive time of flight mass spectrometer (TOF-MS) using 6%vol{sup 18}O{sub 2}/Ar regeneration gas and can reduce markedly procedural complexity. The sorbents were characterized using N{sub 2}-adsorption, high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), temperature-programmed reduction of H{sub 2} (H{sub 2}-TPR), thermogravimetry (TG) and time-of-flight mass spectrometry (TOF-MS) techniques.

  14. Hot wire chemical vapor deposition chemistry in the gas phase and on the catalyst surface with organosilicon compounds.

    Science.gov (United States)

    Shi, Yujun

    2015-02-17

    CONSPECTUS: Hot wire chemical vapor deposition (HWCVD), also referred to as catalytic CVD (Cat-CVD), has been used to produce Si-containing thin films, nanomaterials, and functional polymer coatings that have found wide applications in microelectronic and photovoltaic devices, in automobiles, and in biotechnology. The success of HWCVD is largely due to its various advantages, including high deposition rate, low substrate temperatures, lack of plasma-induced damage, and large-area uniformity. Film growth in HWCVD is induced by reactive species generated from primary decomposition on the metal wire or from secondary reactions in the gas phase. In order to achieve a rational and efficient optimization of the process, it is essential to identify the reactive species and to understand the chemical kinetics that govern the production of these precursor species for film growth. In this Account, we report recent progress in unraveling the complex gas-phase reaction chemistry in the HWCVD growth of silicon carbide thin films using organosilicon compounds as single-source precursors. We have demonstrated that laser ionization mass spectrometry is a powerful diagnostic tool for studying the gas-phase reaction chemistry when combined with the methods of isotope labeling and chemical trapping. The four methyl-substituted silane molecules, belonging to open-chain alkylsilanes, dissociatively adsorb on W and Ta filaments to produce methyl radical and H2 molecule. Under the typical deposition pressures, with increasing number of methyl substitution, the dominant chemistry occurring in the gas phase switches from silylene/silene reactions to free-radical short chain reactions. This change in dominant reaction intermediates from silylene/silene to methyl radicals explains the observation from thin film deposition that silicon carbide films become more C-rich with a decreasing number of Si-H bonds in the four precursor molecules. In the case of cyclic monosilacyclobutanes, we have

  15. Analysis of the photo catalytic degradation of the 4-chloro phenol and endosulfan by gas chromatography

    International Nuclear Information System (INIS)

    The water and soil pollution by organic compounds of considerable toxicity, is every time more alarming. The phenols and organo chlorinated compounds are some of the pollutants of more environmental concern. The present work shows the degradation by heterogeneous photo catalysis of the 4-chloro phenol and endosulfan in watery solutions using a photo reactor at laboratory scale, under ultraviolet irradiation as energy source and titanium dioxide TiO2 Degussa P25 as catalyst. Solutions of both compounds at concentrations of 10, 20, 30 and 40 mg/L were used, analyzing the more important operation parameters with those that the maxima degradation levels were reached. The analyzed variables were catalyst concentration and irradiation time, the analytical techniques of ultraviolet-visible spectroscopy and gas chromatography were used as process control. By means of ultraviolet-visible spectroscopy it was settled down that starting from the quantitative analysis, the 4-chloro phenol presented bigger degradation at smaller concentrations. Under the operation conditions mentioned in this work, it was observed that the photo catalytic processes obey a first order behavior in the chemical kinetics being adjusted to the Langmuir-Hinshelwood model (L-H). With the purpose of checking the degradation of the same ones it was used the gas chromatography, which is an advanced technique for the process pursuit, auxiliary in the quantification and analysis of the photo catalytic degradation of the 4-chloro phenol and endosulfan. It was based on the development and validation of the analytical method, by means of which was proven that the method is good and reliable in the research environment. The results of the quantitative analysis by gas chromatography and ultraviolet-visible, derived of the photo catalytic degradation of the 4-chloro phenol, in the maximum time of study (180 minutes), using the concentrations of 10, 20, 30 and 40 mg/L was found, by gas chromatography, a maximum

  16. The Interaction of the Fermi Bubbles with the Milky Way’s Hot Gas Halo

    Science.gov (United States)

    Miller, Matthew J.; Bregman, Joel N.

    2016-09-01

    The Fermi bubbles are two lobes filled with non-thermal particles that emit gamma rays, extend ≈ 10 {{kpc}} vertically from the Galactic center, and formed from either nuclear star formation or accretion activity on Sgr A*. Simulations predict a range of shock strengths as the bubbles expand into the surrounding hot gas halo ({T}{halo}≈ 2× {10}6 K), but with significant uncertainties in the energetics, age, and thermal gas structure. The bubbles should contain thermal gas with temperatures between 106 and 108 K, with potential X-ray signatures. In this work, we constrain the bubbles’ thermal gas structure by modeling O vii and O viii emission line strengths from archival XMM-Newton and Suzaku data. Our emission model includes a hot thermal volume-filled bubble component cospatial with the gamma-ray region, and a shell of compressed material. We find that a bubble/shell model with n≈ 1× {10}-3 cm‑3 and with log(T) ≈ 6.60–6.70 is consistent with the observed line intensities. In the framework of a continuous Galactic outflow, we infer a bubble expansion rate, age, and energy injection rate of {490}-77+230 km s‑1, {4.3}-1.4+0.8 Myr, and {2.3}-0.9+5.1× {10}42 erg s‑1. These estimates are consistent with the bubbles forming from a Sgr A* accretion event rather than from nuclear star formation.

  17. Infrared Observations of Hot Gas and Cold Ice Toward the Low Mass Protostar Elias 29

    Science.gov (United States)

    Boogert, A. C. A.; Tielens, A. G. G. M.; Ceccarelli, C.; Boonman, A. M. S.; vanDishoeck, E. F.; Keane, J. V.; Whittet, D. C. B.; deGraauw, T.

    2000-01-01

    We have obtained the full 1-200 micrometer spectrum of the low luminosity (36 solar luminosity Class I protostar Elias 29 in the rho Ophiuchi molecular cloud. It provides a unique opportunity to study the origin and evolution of interstellar ice and the interrelationship of interstellar ice and hot core gases around low mass protostars. We see abundant hot CO and H2O gas, as well as the absorption bands of CO, CO2, H2O and "6.85 micrometer" ices. We compare the abundances and physical conditions of the gas and ices toward Elias 29 with the conditions around several well studied luminous, high mass protostars. The high gas temperature and gas/solid ratios resemble those of relatively evolved high mass objects (e.g. GL 2591). However, none of the ice band profiles shows evidence for significant thermal processing, and in this respect Elias 29 resembles the least evolved luminous protostars, such as NGC 7538 : IRS9. Thus we conclude that the heating of the envelope of the low mass object Elias 29 is qualitatively different from that of high mass protostars. This is possibly related to a different density gradient of the envelope or shielding of the ices in a circumstellar disk. This result is important for our understanding of the evolution of interstellar ices, and their relation to cometary ices.

  18. The Interaction of the Fermi Bubbles with the Milky Way's Hot Gas Halo

    CERN Document Server

    Miller, Matthew J

    2016-01-01

    The Fermi bubbles are two lobes filled with non-thermal particles that emit gamma rays, extend $\\approx$10 kpc vertically from the Galactic center, and formed from either nuclear star formation or accretion activity on Sgr A*. Simulations predict a range of shock strengths as the bubbles expand into the surrounding hot gas halo distribution ($T_{halo} \\approx 2 \\times 10^6$ K), but with significant uncertainties in the energetics, age, and thermal gas structure. The bubbles should contain thermal gas with temperatures between $10^6$ and $10^8$ K, with potential X-ray signatures. In this work, we constrain the bubbles' thermal gas structure by modeling the OVII and OVIII emission line strengths from archival XMM-Newton and Suzaku data. Our emission model includes a hot thermal volume-filled bubble component cospatial with the gamma-ray region, and a shell of compressed material. We find that a bubble/shell model with $n \\approx 1 \\times 10^{-3}$ cm$^{-3}$ and with log($T$) $\\approx$ 6.60-6.70 is consistent wit...

  19. Studies on automatic hot gas reader used in the countrywide personnel monitoring programme

    International Nuclear Information System (INIS)

    In India, ∼58,000 radiation workers are monitored using locally made CaSO4:Dy teflon embedded thermoluminescence dosemeter (TLD) badge system. The automatic hot gas readers developed locally are also used in TL measurements. The hot gas reader system has many advantages over the manual readers used previously and has completely replaced the manual reader system in all TLD personnel monitoring units in India. In the present study, the new reader system is studied and a theoretical attempt has been made to interpret the experimentally obtained results. The glow curves are generated theoretically and are also plotted experimentally. It has been found that the heat capacity of the heating gas, which is responsible for the transfer of heat, has a role in deciding the position of peak and is verified experimentally using different gas flow rates of nitrogen and argon as heating gases in the reader. The theoretical study may also be helpful in fitting the experimentally obtained glow curves and, therefore, the elimination of unwanted non-radiation-induced contributions, such as dark current, electronic spikes, light leakage and tribo-luminescence that generally distort the glow curve shape, can be achieved. (authors)

  20. Constraining the dynamical importance of hot gas and radiation pressure in quasar outflows using emission line ratios

    CERN Document Server

    Stern, Jonathan; Zakamska, Nadia L; Hennawi, Joseph F

    2015-01-01

    Quasar feedback models often predict an expanding hot gas bubble which drives a galaxy-scale outflow. In many circumstances the hot gas is predicted to radiate inefficiently, making the hot bubble hard to observe directly. We present an indirect method to detect the presence of a hot bubble using hydrostatic photoionization models of the cold (10^4 K) line-emitting gas. These models assume that the cold gas is in pressure equilibrium with either the hot gas pressure or with the radiation pressure, whichever is larger. We compare our models with observations of the broad line region (BLR), the inner face of the dusty torus, the narrow line region (NLR), and the extended NLR, and thus constrain the hot gas pressure over a dynamical range of 10^5 in radius, from 0.1 pc to 10 kpc. We find that the emission line ratios observed in the average quasar spectrum are consistent with radiation-pressure-dominated models on all scales. On scales > L_AGN/c inferred for galaxy-scale outflows in luminous quasars. This appare...

  1. Catalytic upgrading of gas from biofuels and implementation of electricity production

    Energy Technology Data Exchange (ETDEWEB)

    Simell, P.; Hepola, J.; Heiskanen, K. [VTT Energy, Espoo (Finland)

    1997-10-01

    Kinetic modelling of tar model compound (benzene) reaction with CO{sub 2} over dolomite (Kalkkimaa dolomite) catalyst has been carried out. This modelling has been based mainly on results obtained in earlier project. However, some additional tests have been made to complete the data. The data obtained was fitted to four different Langmuir-Hinshelwood type of kinetic rate equations in order to find the best suited model for the reaction. The model that best described the data assumed single site benzene adsorption and non-dissociative CO{sub 2} adsorption. Kinetical modelling work was continued by studies considering steam reforming of tar. Reaction rates were measured with large excess of water to benzene then with stoichiometric ratio of water to benzene and in simulated gasification gas. Conditions free of external (film) and internal (pore) diffusion effects were used. Reactor was operated both in differential and integral modes. Preliminary modelling was carried out and kinetical parameters for simple first order reaction model were calculated. During the first half of the year complementary experiments concerning earlier studies on sulfur poisoning of nickel catalysts were carried out. The experiments were performed in fixed bed tube reactors and in a TPH-reactor of VTT. In addition, several analytical methods for determining the nature of adsorbed sulfur on the catalyst surface was used. During the other part of the year two complementary report drafts concerning sulfur poisoning of nickel catalysts at hot gas cleaning conditions of gasification gas were prepared. (orig.)

  2. HOT AND COLD GALACTIC GAS IN THE NGC 2563 GALAXY GROUP

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, Jesper [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Bai, Xue-Ning [Department of Astrophysical Sciences, Peyton Hall, Princeton University, NJ 08544 (United States); Mulchaey, John S. [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Van Gorkom, J. H.; Lee, Duane [Department of Astronomy, Columbia University, Mail Code 5246, 550 West 120th Street, New York, NY 10027 (United States); Jeltema, Tesla E. [UCO/Lick Observatories, 1156 High Street, Santa Cruz, CA 95064 (United States); Zabludoff, Ann I. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Wilcots, Eric [Department of Astronomy, University of Wisconsin-Madison, 475 N. Charter St., Madison, WI 53706 (United States); Martini, Paul [Department of Astronomy, 4055 McPherson Laboratory, Ohio State University, 140 West 18th Avenue, Columbus, OH (United States); Roberts, Timothy P., E-mail: jr@dark-cosmology.dk [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)

    2012-03-01

    The role of environmentally induced gas stripping in driving galaxy evolution in groups remains poorly understood. Here we present extensive Chandra and Very Large Array mosaic observations of the hot and cold interstellar medium within the members of the nearby, X-ray bright NGC 2563 group, a prime target for studies of the role of gas stripping and interactions in relatively small host halos. Our observations cover nearly all group members within a projected radius of 1.15 Mpc ({approx}1.4 R{sub vir}) of the group center, down to a limiting X-ray luminosity and H I mass of 3 Multiplication-Sign 10{sup 39} erg s{sup -1} and 2 Multiplication-Sign 10{sup 8} M{sub Sun }, respectively. The X-ray data are consistent with efficient ram pressure stripping of the hot gas halos of early-type galaxies near the group core, but no X-ray tails are seen and the limited statistics preclude strong conclusions. The H I results suggest moderate H I mass loss from the group members when compared to similar field galaxies. Six of the 20 H I-detected group members show H I evidence of ongoing interactions with other galaxies or with the intragroup medium. Suggestive evidence is further seen for galaxies with close neighbors in position-velocity space to show relatively low H I content, consistent with tidal removal of H I. The results thus indicate removal of both hot and cold gas from the group members via a combination of ram pressure stripping and tidal interactions. We also find that 16 of the 20 H I detections occur on one side of the group, reflecting an unusual morphological segregation whose origin remains unclear.

  3. Modelling of non-catalytic reactions in a gas-solid trickle flow reactor: dry, regenerative flue gas desulphurization using a silica-supported copper oxide sorbent

    OpenAIRE

    Kiel, J.H.A.; De Prins, W.; Swaaij, van, W.P.M.

    1992-01-01

    A one-dimensional, two-phase dispersed plug flow model has been developed to describe the steady-state performance of a relatively new type of reactor, the gas-solid trickle flow reactor (GSTFR). In this reactor, an upward-flowing gas phase is contacted with as downward-flowing dilute solids phase over an inert packing. The model is derived from the separate mass heat balances for both the gas and (porous) solids phases for the case of a non-catalytic gas-solid reaction, which is first-order ...

  4. Evaluation of the hot corrosion protection of coatings for first-stage gas turbine blades

    Energy Technology Data Exchange (ETDEWEB)

    Rezakhani, D. [Chemistry and Materials Research Center - Niroo Research Institute End of Pounak-e-Bakhtari Blvd. Tehran (Iran, Islamic Republic of)

    2004-07-01

    Full text of publication follows: This paper was conducted to carry out a comparative evaluation of the hot corrosion resistance of two coatings applied to IN738LC and U-500 gas turbine blade superalloys in laboratory furnace testing. The coatings evaluated included a Cr-aluminide diffusion coating and a CoNiCrAlY overlay. Visual examination, optical metallography and scanning electron microscopy in conjunction with energy-dispersive X-ray analysis and X-ray mapping were used to evaluate the coated samples. Results from these tests showed that both coatings provided corrosion protection. However the metallic overlay coating showed superior hot corrosion protection when compared with Cr-aluminide diffusion coating. (authors)

  5. Hot gas ingestion characteristics and flow visualization of a vectored thrust STOVL concept

    Science.gov (United States)

    Johns, Albert L.; Neiner, George H.; Bencic, Timothy J.; Flood, Joseph D.; Amuedo, Kurt C.; Strock, Thomas W.; Williams, Ben R.

    1990-01-01

    The study presents results obtained at the compressor face of a 9.2-percent scale vectored thrust model in ground effects from Phases I and II of a test program to evaluate the hot ingestion phenomena and control techniques, and to conduct flow visualization of the model flowfield in and out of ground effects, respectively. A description of the model, facility, a new model support system, and a sheet laser illumination system are provided. The findings contain the compressor face pressure and temperature distortions, compressor face temperature rise, and the environmental effects of the hot gas. The environmental effects include the ground plane temperature and pressure distributions, model airframe heating, and the location of the ground flow separation. Results from the sheet laser flow visualization test are also presented.

  6. Hot surface assisted compression ignition in a direct injection natural gas engine

    Energy Technology Data Exchange (ETDEWEB)

    Aesoey, Vilmar

    1996-12-31

    This study investigates the problem of ignition in a direct injection natural gas engine. Due to poor auto-ignition properties of natural gas compared to regular diesel engine fuels, a special arrangement to assist and secure ignition is required. The objective was to investigate the feasibility of using a hot surface as ignition assistance, primarily for application in medium and large size engines, and further study the main mechanisms involved in the ignition process. A constant volume combustion bomb and a test engine are used for experiments, supported by theoretical analysis and numerical simulations. Variable composition of natural gas depending on the gas source and over time, is a important problem causing significant variation in ignition properties. It is shown that even small quantities of non-methane components, which are normally present in natural gases, strongly influence ignition. Actions to handle the ignition problem caused by variable natural composition, are also discussed. In order to estimate the ignition properties of natural gas, a simple correlation to gas composition is proposed, showing good correlation to the experimental data. Mathematical models for simulation of the processes are developed based on fundamental physical relations and experimental results. They are mainly used in this study to support and analyze the physical experiments, but can also be useful in future design and optimization processes. 71 refs., 80 figs., 6 tabs.

  7. Data acquisition and quantitative analysis of stable hydrogen isotope in liquid and gas in the liquid phase catalytic exchange process

    International Nuclear Information System (INIS)

    A pilot plant for the Liquid Phase Catalytic Exchange process was built and has been operating to test the hydrophobic catalyst developed to remove the tritium generated at the CANDU nuclear power plants. The methods of quantitative analysis of hydrogen stable isotope were compared. Infrared spectroscopy was used for the liquid samples, and gas chromatography with hydrogen carrier gas showed the best result for gas samples. Also, a data acquisition system was developed to record the operation parameters. This record was very useful to investigate the causes of the system trip

  8. Hot and Cold Galactic Gas in the NGC 2563 Galaxy Group

    CERN Document Server

    Rasmussen, Jesper; Mulchaey, John S; van Gorkom, J H; Jeltema, Tesla E; Zabludoff, Ann I; Wilcots, Eric; Martini, Paul; Lee, Duane; Roberts, Timothy P

    2012-01-01

    The role of environmentally induced gas stripping in driving galaxy evolution in groups remains poorly understood. Here we present extensive Chandra and Very Large Array mosaic observations of the hot and cold interstellar medium within the members of the nearby, X-ray bright NGC 2563 group, a prime target for studies of the role of gas stripping and interactions in relatively small host halos. Our observations cover nearly all group members within a projected radius of 1.15 Mpc (~1.4 R_vir) of the group center, down to a limiting X-ray luminosity and HI mass of 3e39 erg/s and 2e8 M_sun, respectively. The X-ray data are consistent with efficient ram pressure stripping of the hot gas halos of early-type galaxies near the group core, but no X-ray tails are seen and the limited statistics preclude strong conclusions. The HI results suggest moderate HI mass loss from the group members when compared to similar field galaxies. Six of the 20 HI-detected group members show HI evidence of ongoing interactions with oth...

  9. Effects of hot halo gas on the star formation and mass transfer during distant galaxy-galaxy encounters

    CERN Document Server

    Hwang, Jeong-Sun

    2015-01-01

    We use $N$-body/smoothed particle hydrodynamics simulations of encounters between an early-type galaxy (ETG) and a late-type galaxy (LTG) to study the effects of hot halo gas on the evolution for a case with the mass ratio of the ETG to LTG of 2:1 and the closest approach distance of $\\sim$100 kpc. We find that the dynamics of the cold disk gas in the tidal bridge and the amount of the newly formed stars depend strongly on the existence of a gas halo. In the run of interacting galaxies not having a hot gas halo, the gas and stars accreted into the ETG do not include newly formed stars. However, in the run using the ETG with a gas halo and the LTG without a gas halo, a shock forms along the disk gas tidal bridge and induces star formation near the closest approach. The shock front is parallel to a channel along which the cold gas flows toward the center of the ETG. As a result, the ETG can accrete star-forming cold gas and newly born stars at and near its center. When both galaxies have hot gas halos, a shock ...

  10. Absorption signatures of warm-hot gas at low redshift: Broad Lyman-Alpha Absorbers

    CERN Document Server

    Tepper-García, Thorsten; Schaye, Joop; Booth, Craig M; Vecchia, Claudio Dalla; Theuns, Tom

    2012-01-01

    We investigate the physical state of HI absorbing gas at low redshift (z=0.25) using a subset of cosmological, hydrodynamic simulations from the OWLS project, focusing in particular on broad (b_HI > 40 km/s) Lyman-Alpha absorbers (BLAs), which are believed to originate in shock-heated gas in the Warm-Hot Intergalactic Medium (WHIM). Our fiducial model, which includes radiative cooling by heavy elements and feedback by supernovae and active galactic nuclei, predicts that by z=0.25 nearly 60 per cent of the gas mass ends up at densities and temperatures characteristic of the WHIM and we find that half of this fraction is due to outflows. The standard HI observables (distribution of HI column densities N_HI, distribution of Doppler parameters b_HI, b_HI - N_HI correlation) and the BLA line number density predicted by our simulations are in remarkably good agreement with observations. BLAs arise in gas that is hotter, more highly ionised and more enriched than the gas giving rise to typical Lyman-Alpha forest abs...

  11. Gas Engine-Driven Heat Pump Chiller for Air-Conditioning and Hot Water Supply Systems

    Science.gov (United States)

    Fujita, Toshihiko; Mita, Nobuhiro; Moriyama, Tadashi; Hoshino, Norimasa; Kimura, Yoshihisa

    In Part 1 of this study, the performance characteristics of a 457kW gas engine-driven heat pump (GHP) chiller have been obtained from a simulation model analysis for both cooling and heating modes and it has been found that the part-load characteristics of the GHP chiller are fairly well. On the back of Part 1, a computer simulation program has been developed for the evaluation of GHP chiller systems to compare with the other types of heat source systems for air-conditioning and hot water supply applications. The simulation program can be used to estimate annual energy consumption, annual CO2 emission, etc. of the systems with the data of monthly and hourly thermal loads on various buildings, outdoor air conditions, and characteristics of various components comprising the systems. By applying this to some cases of medium-scale hotel, office, shop, and hospital buildings, it has been found that the GHP chiller systems have advantages particularly in the cases of hotels and hospitals where a lot of hot water demand exists. It has also been found that the combination of a GHP chiller and a direct-fired absorption water chiller boiler (hot and chilled water generator) appears promising.

  12. Catalytic Properties of Mesoporous Silica (FSM-16) for Beckmann Rearrangement of Cyclohexanone Oxime in Gas Phase

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, T. [Shinshu Univ, Nagano (Japan). Department of Chemistry and Material Engineering Facutly of Engineering; Nakajima, T. [Iiyama Electric Co. Ltd., Nagano (Japan); Mishima, S. [Shinshu Univ, Nagano (Japan). Cooperative Research Center

    1997-08-10

    Catalytic properties of FSM-16 (porous silica with the honeycomb structure of uniform mesopores) were investigated for Beckmann rearrangement of cyclohexanone oxime in gas phase at 523-623 K, and were compared with those of other typical solid acid catalysts. FSM-16 was found to be a long-life catalyst and exhibited higher conversion of the oxime than silica-alumina, H-ZSM-5, Na-ZSM-5, HX-zeolite, and {gamma}-alumina. Selectivity for {epsilon}-caprolactam of FSM-16 was 42-25%, which was lower than that of H-ZSM-5 (89%), silica-alumina (77%), and HX-zeolite (74%). The product composition given by FSM-16 was very similar to that by silica gel. FSM-16, which was impregnated with a solution of aluminum nitrate and then calcined at 823 K, exhibited a higher selectivity (54%) for {epsilon}-caprolactam than an original one. The activity of FSM-16 was remarkably decreased when the catalyst was calcined at 1073 K or above. However, the selectivity for {epsilon}-caprolactam scarcely changed. 10 refs., 4 figs., 1 tab.

  13. A flameless catalytic combustion-based thermoelectric generator for powering electronic instruments on gas pipelines

    International Nuclear Information System (INIS)

    Highlights: ► MPPT is used to improve the feature that TEG output is sensitive to load variation. ► The improved feature makes TEG suitable to power electronic device on gas pipeline. ► Test shows heat transfer uniformity plays an important role in improving TEG output. ► It can get an optimized TEG by uniformly filling a thermal insulation material. - Abstract: This paper presents a flameless catalytic combustion-based thermoelectric power generator that uses commercial thermoelectric modules. The structure of the thermoelectric generator (TEG) is introduced and the power performance is measured based on a designed circuit system. The open circuit voltage of the TEG is about 7.3 V. The maximum power output can reach up to 6.5 W when the load resistance matches the TEG internal resistance. However, the system output is sensitive to load variation. To improve this characteristic, maximum power point tracking technique is used and results in an open circuit voltage of 13.8 V. The improved characteristic makes the TEG system a good charger to keep the lead acid battery fully charged so as to meet the needs of electronic instruments on gas pipelines. In addition, the combustion features have been investigated based on the temperature measurement. Test results show that the uniformity of combustion heat transfer process and the combustion chamber structure play important roles in improving system power output. It can get an optimized TEG system (maximum power output: 8.3 W) by uniformly filling a thermal insulation material (asbestos) to avoid a non-uniform combustion heat transfer process

  14. A study on thermodynamical properties of hot and dense hadron gas using the event generator

    CERN Document Server

    Sasaki, N

    2001-01-01

    We investigate the equilibration and the equation of state of the hot hadron gas at finite baryon density using an event generator that satisfies detailed balance at temperatures and baryon densities of present interests (80 < T < 170 MeV, 0.157 < n_B < 0.315 fm^-3). Molecular-dynamic-simulations are performed to the system of hadrons in the box with periodic boundary conditions. Starting from an initial condition composed of nucleons with uniform momentum distribution, the evolution takes place through interactions, productions and absorptions. The system approaches to a stationary state of baryons, mesons and their resonances. The system is characterized by an exponent in the energy distribution irrespective of the particle species, i.e., temperature. After the equilibration, thermodynamical quantities such as energy density, particle density, entropy and pressure are calculated. Obtained equation of state shows a remarkable deviation from the mixed free gas of mesons and baryons above T = m_pi....

  15. Simulating the escaping atmospheres of hot gas planets in the solar neighborhood

    CERN Document Server

    Salz, M; Schneider, P C; Schmitt, J H M M

    2016-01-01

    Absorption of high-energy radiation in planetary thermospheres is believed to lead to the formation of planetary winds. The resulting mass-loss rates can affect the evolution, particularly of small gas planets. We present 1D, spherically symmetric hydrodynamic simulations of the escaping atmospheres of 18 hot gas planets in the solar neighborhood. Our sample only includes strongly irradiated planets, whose expanded atmospheres may be detectable via transit spectroscopy. The simulations were performed with the PLUTO-CLOUDY interface, which couples a detailed photoionization and plasma simulation code with a general MHD code. We study the thermospheric escape and derive improved estimates for the planetary mass-loss rates. Our simulations reproduce the temperature-pressure profile measured via sodium D absorption in HD 189733 b, but show unexplained differences in the case of HD 209458 b. In contrast to general assumptions, we find that the gravitationally more tightly bound thermospheres of massive and compact...

  16. Non-intrusive measurement of hot gas temperature in a gas turbine engine

    Energy Technology Data Exchange (ETDEWEB)

    DeSilva, Upul P.; Claussen, Heiko; Yan, Michelle Xiaohong; Rosca, Justinian; Ulerich, Nancy H.

    2016-09-27

    A method and apparatus for operating a gas turbine engine including determining a temperature of a working gas at a predetermined axial location within the engine. An acoustic signal is encoded with a distinct signature defined by a set of predetermined frequencies transmitted as a non-broadband signal. Acoustic signals are transmitted from an acoustic transmitter located at a predetermined axial location along the flow path of the gas turbine engine. A received signal is compared to one or more transmitted signals to identify a similarity of the received signal to a transmitted signal to identify a transmission time for the received signal. A time-of-flight is determined for the signal and the time-of-flight for the signal is processed to determine a temperature in a region of the predetermined axial location.

  17. Efficiency enhancement in IGCC power plants with air-blown gasification and hot gas clean-up

    International Nuclear Information System (INIS)

    Air-blown IGCC systems with hot fuel gas clean-up are investigated. In detail, the gas clean-up station consists of two reactors: in the first, the raw syngas exiting the gasifier and passed through high-temperature syngas coolers is desulfurized by means of a zinc oxide-based sorbent, whereas in the second the sulfided sorbent is duly regenerated. The hot fuel gas clean-up station releases H2S-free syngas, which is ready to fuel the combustion turbine after hot gas filtration, and a SO2-laden stream, which is successively treated in a wet scrubber. A thermodynamic analysis of two air-blown IGCC systems, the first with cold fuel gas clean-up and the second with hot fuel gas clean-up, both with a state-of-the-art combustion turbine as topping cycle, shows that it is possible to obtain a really attractive net efficiency (more than 51%) for the second system, with significant improvements in comparison with the first system. Nevertheless, higher efficiency is accomplished with a small reduction in the power output and no sensible efficiency improvements seem to be appreciated when the desulfurization temperature increases. Other IGCC systems, with an advanced 1500 °C-class combustion turbine as the result of technology improvements, are investigated as well, with efficiency as high as 53%. - Highlights: ► Hot fuel gas clean-up is a highly favorable technology for IGCC concepts. ► Significant IGCC efficiency improvements are possible with hot fuel gas clean-up. ► Size reductions of several IGCC components are possible. ► Higher desulfurization temperatures do not sensibly affect IGCC efficiency. ► IGCC efficiency as high as 53% is possible with a 1500°C-class combustion turbine

  18. Carbon nanotube growth from catalytic nano-clusters formed by hot-ion-implantation into the SiO{sub 2}/Si interface

    Energy Technology Data Exchange (ETDEWEB)

    Hoshino, Yasushi, E-mail: yhoshino@kanagawa-u.ac.jp [Department of Information Sciences, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293 (Japan); Arima, Hiroki; Yokoyama, Ai; Saito, Yasunao; Nakata, Jyoji [Department of Information Sciences, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293 (Japan)

    2012-07-01

    We have studied growth of chirality-controlled carbon nanotubes (CNTs) from hot-implantation-formed catalytic nano-clusters in a thermally grown SiO{sub 2}/Si substrate. This procedure has the advantage of high controllability of the diameter and the number of clusters by optimizing the conditions of the ion implantation. In the present study, Co{sup +} ions with ion dose of 8 Multiplication-Sign 10{sup 16} cm{sup -2} are implanted in the vicinity of the SiO{sub 2}/Si interface at 300 Degree-Sign C temperature. The implanted Co atoms located in the SiO{sub 2} layer has an amorphous-like structure with a cluster diameter of several nm. In contrast, implanted Co atoms in the Si substrate are found to take a cobalt silicide structure, confirmed by the high-resolution image of transmission electron microscope. CNTs are grown by microwave-plasma-enhanced chemical vapor deposition. We have confirmed a large amount of vertically-aligned multi-walled CNTs from the Co nano-clusters formed by the hot-ion-implantation near the SiO{sub 2}/Si interface.

  19. Catalytic upgrading of gas from biofuels and implementation of electricity production. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Espenaes, Bengt-Goeran; Frostaeng, Sten [TPS Termiska Processer AB, Nykoeping (Sweden)

    2000-04-01

    components concerned are typically aromatic hydrocarbons. These investigations were done using basic oxides (e.g. dolomite), and nickel-based catalysts. Data were collected at different gas compositions and temperatures. Interdependence of reaction rates of some most stable tar components was investigated with dolomite as catalyst. New insights were obtained concerning the reaction mechanism of the decomposition of aromatic compounds catalysed by dolomite. Among issues studied were relations between pore structure and catalytic ability, and influences from the conditions during calcination. The role of intermediate carbon formation on dolomite during decomposition of aromatic hydrocarbons was investigated. Several suggested kinetic rate model equations were evaluated. Internal surface areas of calcined dolomite of different origin were investigated and correlated to their catalytic activity. Kinetics of tar conversion with dolomite and nickel catalysts was included in reactor models. Different models were formulated and tested for different types of reactors. A model for the physical degradation behaviour of dolomite and carry-over of fines in fluidized beds was formulated. A number of new suggested catalysts and catalyst combinations were tested. One interesting new approach is to use a SiO{sub 2} material with large surface area in combination with another catalyst, e.g. dolomite. Another novel catalyst gave very good conversion of benzene at 480 deg C in a 'clean' synthetic gas mixture. Further testing of this catalyst at realistic conditions will be needed. Relations between raw materials and tar formation was investigated in experiments with thermal and catalytic treatment in a secondary reactor after a pyrolyser and comparisons were done with results from gasification. Tar products distribution and amounts were found to be influenced by feedstock. These differences decrease with increasing cracking temperature and efficiency of the catalyst. The sampling and

  20. Investigating hot gas in the halos of two massive spirals: Observations and cosmological simulations

    CERN Document Server

    Rasmussen, J; Pedersen, K; Toft, S; Benson, A; Bower, R G; Olsen, L F; Rasmussen, Jesper; Sommer-Larsen, Jesper; Pedersen, Kristian; Toft, Sune; Benson, Andrew; Bower, Richard G.; Olsen, Lisbeth F.

    2006-01-01

    Models of disk galaxy formation commonly predict the existence of an extended reservoir of hot gas surrounding massive spirals at low redshift. As a test of these models, we have obtained X-ray and optical data of the two massive edge-on spirals NGC 5746 and NGC 5170, in order to investigate the amount and origin of hot gas in their disks and halos. Chandra observations of NGC 5746 reveal evidence for diffuse X-ray emission with a total luminosity of ~7 x 10^39 erg/s surrounding this galaxy out to at least ~20 kpc from the disk, whereas an identical study of the less massive NGC 5170 fails to detect any extraplanar X-ray emission. Unlike the case for other disk galaxies with detected X-ray halos, the halo emission around NGC 5746 is not accompanied by extraplanar H-alpha or radio emission, and there is no evidence for significant nuclear or starburst activity in the disk. In contrast to these other cases, the emission around NGC 5746 therefore appears to arise from the cooling of externally accreted material ...

  1. Investigation of austenitic alloys for advanced heat recovery and hot gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.; Ren, W.

    1996-06-01

    The objective of the research is to provide databases and design criteria to assist in the selection of optimum alloys for construction of components needed to contain process streams in advanced heat recovery and hot-gas cleanup systems. Typical components include: steam line piping and superheater tubing for low emission boilers (600 to 700{degrees}C), heat exchanger tubing for advanced steam cycles and topping cycle systems (650 to 800{degrees}C), foil materials for recuperators, on advanced turbine systems (700 to 750{degrees}C), and tubesheets for barrier filters, liners for piping, cyclones, and blowback system tubing for hot-gas cleanup systems (850 to 1000{degrees}C). The materials being examined fall into several classes, depending on which of the advanced heat recovery concepts is of concern. These classes include martensitic steels for service to 650{degrees}C, lean stainless steels and modified 25Cr-30Ni steels for service to 700{degrees}C, modified 25Cr-20Ni steels for service to 900{degrees}C, and high Ni-Cr-Fe or Ni-Cr-Co-Fe alloys for service to 1000{degrees}C.

  2. FIR Spectroscopy of the Galactic Center: Hot and Warm Molecular Gas

    CERN Document Server

    Goicoechea, J R; Cernicharo, J; Gerin, M; Pety, J

    2016-01-01

    The angular resolution (~10") achieved by the Herschel Space Observatory ~3.5m telescope at FIR wavelengths allowed us to roughly separate the emission toward the inner parsec of the galaxy (the central cavity) from that of the surrounding circumnuclear disk (the CND). The FIR spectrum toward SgrA* is dominated by intense [Oiii], [Oi], [Cii], [Niii], [Nii], and [Ci] fine-structure lines (in decreasing order of luminosity) arising in gas irradiated by the strong UV field from the central stellar cluster. The high-J CO rotational line intensities observed at the interface between the inner CND and the central cavity are consistent with a hot isothermal component at T~10^{3.1} K and n(H_2)~10^4 cm^{-3}. They are also consistent with a distribution of lower temperatures at higher gas density, with most CO at T~300 K. The hot CO component (either the bulk of the CO column density or just a small fraction depending on the above scenario) likely results from a combination of UV and shock-driven heating. Although thi...

  3. Catalytic pyrolysis of biomass: Effects of pyrolysis temperature, sweeping gas flow rate and MgO catalyst

    International Nuclear Information System (INIS)

    Cotton seed, as a biomass source, is pyrolysed in a tubular fixed-bed reactor under various sweeping gas (N2) flow rates at different pyrolysis temperatures. In the non-catalytic work, the maximum bio-oil yield was attained as 48.30% at 550 oC with a sweeping gas flow rate of 200 mL min-1. At the optimum conditions, catalytic pyrolysis of biomass samples was performed with various amounts of MgO catalyst (5, 10, 15, and 20 wt.% of raw material). Catalyst addition decreased the quantity of bio-oil yet increased the quality of bio-oil in terms of calorific value, hydrocarbon distribution and removal of oxygenated groups. It was observed that increasing the amount of catalyst used, decreased the oil yields while increased the gas and char yields. Bio-oils obtained at the optimum conditions were separated into aliphatic, aromatic and polar sub-fractions. After the application of column chromatography, bio-oils were subjected into elemental, FT-IR and 1H NMR analyses. Aliphatic sub-fractions of bio-oils were analyzed by GC-MS. It was deduced that the fuel obtained via catalytic pyrolysis mainly consisted of lower weight hydrocarbons in the diesel range. Finally, obtained results were compared with petroleum fractions and evaluated as a potential source for liquid fuels.

  4. Determination of the gas-to-membrane mass transfer coefficient in a catalytic membrane reactor

    NARCIS (Netherlands)

    Veldsink, J.W.; Versteeg, G.F.; Swaaij, W.P.M. van

    1995-01-01

    A novel method to determine the external mass transfer coefficient in catalytic membrane reactors (Sloot et al., 1992a, b) was presented in this study. In a catalytically active membrane reactor, in which a very fast reaction occurs, the external transfer coefficient can conveniently be measured by

  5. A comparative study of naturally ventilated and gas filled windows for hot climates

    International Nuclear Information System (INIS)

    The use of absorbing gases filling the gap between glass sheets appears to be an alternative solution for thermally insulated glass windows. Fluid flow in the gap between the glass sheets either forced or natural offers other options for thermally efficient windows. In this work, the thermal efficiencies of glass windows filled with an absorbing gas exposed to solar radiation in hot climate is compared with both a simple glass window and a double glass window naturally ventilated. The two-dimensional transient energy equations with radiation absorption in the internal domain are used to model the simple glass window. The cumulative wavenumber model (CW) for real gas modeling together the discrete ordinates method is used to model double glass window filled with infrared absorbing gases. The numerical simulations were realized with three mixtures of gases, a strongly absorbing gas mixture, an intermediate absorbing gas mixture and a transparent to infrared radiation mixture. To model a double glass window naturally ventilated, a two-dimensional transient laminar incompressible flow formulation is used and the buoyancy effects are accounting for by the Bussinesq approximation. Heat transfer through the windows is calculated and the total heat gain coefficient is compared for the three types of windows.

  6. Survival of molecular gas in Virgo's hot intracluster medium: CO near M86

    CERN Document Server

    Dasyra, K M; Salome, P; Braine, J

    2012-01-01

    We carried out CO(1-0) and CO(2-1) observations of 21 different regions in the vicinity of M86, NGC4438, and along the 120 kpc-long, Ha-emitting filamentary trail that connects them, aiming to test whether molecular gas can survive to be transferred from a spiral to an elliptical galaxy in Virgo's 10^7K intracluster medium (ICM). We targeted Ha-emitting regions that could be associated with the interface between cold molecular clouds and the hot ionized ICM. The data, obtained with the 30m telescope of the Institut de Radioastronomie Millimetrique, led to the detection of molecular gas close to M86. CO gas with a recession velocity that is similar to that of the stars, -265 km/s, and with a corresponding H2 mass of 2*10^7 M_sun, was detected ~10 kpc south east of the nucleus of M86, near the peak of its HI emission. We argue that it is possible for this molecular gas either to have formed in situ from HI, or to have been stripped from NGC4438 directly in molecular form. In situ formation is nonetheless neglig...

  7. Hot gas cleaning in power stations by using electron beam technology. Influence on PAH emissions

    International Nuclear Information System (INIS)

    The Electron Beam Technology (EBT), proven treatment for SO2 and NOx removal, is applied to different power stations as a hot gas cleaning system. In this paper, an assessment of this technique installed in a Bulgarian power station on organic emissions is analyzed. The Polycyclic Aromatic Hydrocarbons (PAH) content, not only emitted in the gas phase but also trapped in the solid phase, has been carried out before and after the irradiation. The main aim has been to know whether the EBT affects organic emissions, like PAH, as it happens with inorganic pollutants, like SO2 and NOx, studying EBT effects from an organic environmental point of view. The PAH quantification was performed by using a very sensitive analytical technique, gas chromatography with mass spectrometry mass spectrometry detection (GC-MS-MS). Results showed that PAH are influenced by the EBT showing a reduction of the most volatile PAH in the gas phase. With regard to the solid by-products obtained after the irradiation, fertilizers, similar PAH concentration to the fly ashes produced when no irradiation is applied were found. These fertilizers were considered like unpolluted soils being adequate for agriculture applications with PAH concentrations below the target value set up by the Dutch government. (author)

  8. Gas temperature measurements inside a hot wall chemical vapor synthesis reactor.

    Science.gov (United States)

    Notthoff, Christian; Schilling, Carolin; Winterer, Markus

    2012-11-01

    One key but complex parameter in the chemical vapor synthesis (CVS) of nanoparticles is the time temperature profile of the gas phase, which determines particle characteristics such as size (distribution), morphology, microstructure, crystal, and local structure. Relevant for the CVS process and for the corresponding particle characteristics is, however, not the T(t)-profile generated by an external energy source such as a hot wall or microwave reactor but the temperature of the gas carrying reactants and products (particles). Due to a complex feedback of the thermodynamic and chemical processes in the reaction volume with the external energy source, it is very difficult to predict the real gas phase temperature field from the externally applied T(t)-profile. Therefore, a measurement technique capable to determine the temperature distribution of the gas phase under process conditions is needed. In this contribution, we demonstrate with three proof of principle experiments the use of laser induced fluorescence thermometry to investigate the CVS process under realistic conditions.

  9. Local ISM 3D Distribution and Soft X-ray Background Inferences for Nearby Hot Gas

    Science.gov (United States)

    Puspitarini, L.; Lallement, R.; Snowden, Steven L.; Vergely, J.-L.; Snowden, S.

    2014-01-01

    Three-dimensional (3D) interstellar medium (ISM) maps can be used to locate not only interstellar (IS) clouds, but also IS bubbles between the clouds that are blown by stellar winds and supernovae, and are filled by hot gas. To demonstrate this, and to derive a clearer picture of the local ISM, we compare our recent 3D IS dust distribution maps to the ROSAT diffuse Xray background maps after removal of heliospheric emission. In the Galactic plane, there is a good correspondence between the locations and extents of the mapped nearby cavities and the soft (0.25 keV) background emission distribution, showing that most of these nearby cavities contribute to this soft X-ray emission. Assuming a constant dust to gas ratio and homogeneous 106 K hot gas filling the cavities, we modeled in a simple way the 0.25 keV surface brightness along the Galactic plane as seen from the Sun, taking into account the absorption by the mapped clouds. The data-model comparison favors the existence of hot gas in the solar neighborhood, the so-called Local Bubble (LB). The inferred mean pressure in the local cavities is found to be approx.9,400/cu cm K, in agreement with previous studies, providing a validation test for the method. On the other hand, the model overestimates the emission from the huge cavities located in the third quadrant. Using CaII absorption data, we show that the dust to CaII ratio is very small in those regions, implying the presence of a large quantity of lower temperature (non-X-ray emitting) ionized gas and as a consequence a reduction of the volume filled by hot gas, explaining at least part of the discrepancy. In the meridian plane, the two main brightness enhancements coincide well with the LB's most elongated parts and chimneys connecting the LB to the halo, but no particular nearby cavity is found towards the enhancement in the direction of the bright North Polar Spur (NPS) at high latitude. We searched in the 3D maps for the source regions of the higher energy

  10. Viewing inside Pyroclastic Flows - Large-scale Experiments on hot pyroclast-gas mixture flows

    Science.gov (United States)

    Breard, E. C.; Lube, G.; Cronin, S. J.; Jones, J.

    2014-12-01

    Pyroclastic density currents are the largest threat from volcanoes. Direct observations of natural flows are persistently prevented because of their violence and remain limited to broad estimates of bulk flow behaviour. The Pyroclastic Flow Generator - a large-scale experimental facility to synthesize hot gas-particle mixture flows scaled to pyroclastic flows and surges - allows investigating the physical processes behind PDC behaviour in safety. The ability to simulate natural eruption conditions and to view and measure inside the hot flows allows deriving validation and calibration data sets for existing numerical models, and to improve the constitutive relationships necessary for their effective use as powerful tools in hazard assessment. We here report on a systematic series of large-scale experiments on up to 30 ms-1 fast, 2-4.5 m thick, 20-35 m long flows of natural pyroclastic material and gas. We will show high-speed movies and non-invasive sensor data that detail the internal structure of the analogue pyroclastic flows. The experimental PDCs are synthesized by the controlled 'eruption column collapse' of variably diluted suspensions into an instrumented channel. Experiments show four flow phases: mixture acceleration and dilution during free fall; impact and lateral blasting; PDC runout; and co-ignimbrite cloud formation. The fully turbulent flows reach Reynolds number up to 107 and depositional facies similar to natural deposits. In the PDC runout phase, the shear flows develop a four-partite structure from top to base: a fully turbulent, strongly density-stratified ash cloud with average particle concentrations energy and momentum through their interfaces via vertical time-series profiles of velocity, particle concentration, gas and particle transport directionality and turbulent eddy characteristics. We highlight the importance of each region for the PDC runout dynamics and introduce a new transport and sedimentation model for downslope evolving

  11. The Atlas3D project - XIX. The hot-gas content of early-type galaxies: fast versus slow rotators

    CERN Document Server

    Sarzi, Marc; Blitz, Leo; Bois, Maxime; Bournaud, Frederic; Bureau, M; Cappellari, Michele; Crocker, Alison F; Davies, Roger L; Davis, Timothy A; de Zeeuw, P T; Duc, Pierre-Alain; Khochfar, Sadegh; Krajnovic, Davor; Kuntschner, Harald; McDermid, Richard M; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M

    2013-01-01

    For early-type galaxies, the ability to sustain a corona of hot, X-ray emitting gas could have played a key role in quenching their star-formation history. Yet, it is still unclear what drives the precise amount of hot gas around these galaxies. By combining photometric and spectroscopic measurements for the early-type galaxies observed during the Atlas3D integral-field survey with measurements of their X-ray luminosity based on X-ray data of both low and high spatial resolution we conclude that the hot-gas content of early-type galaxies can depend on their dynamical structure. Specifically, whereas slow rotators generally have X-ray halos with luminosity L_X,gas and temperature T values that are in line with what is expected if the hot-gas emission is sustained by the thermalisaton of the kinetic energy carried by the stellar-mass loss material, fast rotators tend to display L_X,gas values that fall consistently below the prediction of this model, with similar T values that do not scale with the stellar kine...

  12. Hot Gas Particulate Cleaning Technology Applied for PFBC/IGFC -The Ceramic Tube Filter (CTF) and Metal Filter-

    Energy Technology Data Exchange (ETDEWEB)

    Sasatsu, H; Misawa, N; Kobori, K; Iritani, J

    2002-09-18

    Coal is a fossil fuel abundant and widespread all over world. It is a vital resource for energy security, because the supply is stable. However, its CO2 emission per unit calorific value is greater than that of other fossil fuels. It is necessary to develop more efficient coal utilization technologies to expand the coal utilization that meets the social demand for better environment. The Pressurized Fluidized Bed Combustion (PFBC) combined cycle has become a subject of world attention in terms of better plant operation, improved plant efficiency, lower flue gas emission and fuel flexibility. The gas turbine, one of the most important components in the PFBC, is eager for a hot gas (approximately 650-850C) cleaning system in order to eliminate the severe erosion problem with the less thermal loss. The cyclone is most popular system for a hot gas cleaning, however, the severe damage for gas turbine blades by highly concentrated fine fly ash from PFBC boiler is reported.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, F.M. [Department of Chemistry, Tianjin University, Tianjin 300072 (China); Liu, B.S., E-mail: bingsiliu@tju.edu.cn [Department of Chemistry, Tianjin University, Tianjin 300072 (China); Zhang, Y.; Guo, Y.H.; Wan, Z.Y.; Subhan, Fazle [Department of Chemistry, Tianjin University, Tianjin 300072 (China)

    2012-09-30

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

  14. GARROTXA Cosmological Simulations of Milky Way-sized Galaxies: General Properties, Hot-gas Distribution, and Missing Baryons

    Science.gov (United States)

    Roca-Fàbrega, Santi; Valenzuela, Octavio; Colín, Pedro; Figueras, Francesca; Krongold, Yair; Velázquez, Héctor; Avila-Reese, Vladimir; Ibarra-Medel, Hector

    2016-06-01

    We introduce a new set of simulations of Milky Way (MW)-sized galaxies using the AMR code ART + hydrodynamics in a Λ cold dark matter cosmogony. The simulation series is called GARROTXA and it follows the formation of a halo/galaxy from z = 60 to z = 0. The final virial mass of the system is ˜7.4 × 1011 M ⊙. Our results are as follows. (a) Contrary to many previous studies, the circular velocity curve shows no central peak and overall agrees with recent MW observations. (b) Other quantities, such as M\\_\\ast (6 × 1010 M ⊙) and R d (2.56 kpc), fall well inside the observational MW range. (c) We measure the disk-to-total ratio kinematically and find that D/T = 0.42. (d) The cold-gas fraction and star formation rate at z = 0, on the other hand, fall short of the values estimated for the MW. As a first scientific exploitation of the simulation series, we study the spatial distribution of hot X-ray luminous gas. We have found that most of this X-ray emitting gas is in a halo-like distribution accounting for an important fraction but not all of the missing baryons. An important amount of hot gas is also present in filaments. In all our models there is not a massive disk-like hot-gas distribution dominating the column density. Our analysis of hot-gas mock observations reveals that the homogeneity assumption leads to an overestimation of the total mass by factors of 3-5 or to an underestimation by factors of 0.7-0.1, depending on the used observational method. Finally, we confirm a clear correlation between the total hot-gas mass and the dark matter halo mass of galactic systems.

  15. Pretreated Landfill Gas Conversion Process via a Catalytic Membrane Reactor for Renewable Combined Fuel Cell-Power Generation

    Directory of Open Access Journals (Sweden)

    Zoe Ziaka

    2013-01-01

    Full Text Available A new landfill gas-based reforming catalytic processing system for the conversion of gaseous hydrocarbons, such as incoming methane to hydrogen and carbon oxide mixtures, is described and analyzed. The exit synthesis gas (syn-gas is fed to power effectively high-temperature fuel cells such as SOFC types for combined efficient electricity generation. The current research work is also referred on the description and design aspects of permreactors (permeable reformers carrying the same type of landfill gas-reforming reactions. Membrane reactors is a new technology that can be applied efficiently in such systems. Membrane reactors seem to perform better than the nonmembrane traditional reactors. The aim of this research includes turnkey system and process development for the landfill-based power generation and fuel cell industries. Also, a discussion of the efficient utilization of landfill and waste type resources for combined green-type/renewable power generation with increased processing capacity and efficiency via fuel cell systems is taking place. Moreover, pollution reduction is an additional design consideration in the current catalytic processors fuel cell cycles.

  16. Transverse azimuthal dephasing of vortex spin wave in a hot atomic gas

    CERN Document Server

    Shi, Shuai; Zhang, Wei; Zhou, Zhi-Yuan; Dong, Ming-Xin; Liu, Shi-Long; Shi, Bao-Sen; Guo, Guang-Can

    2016-01-01

    Optical fields with orbital angular momentum (OAM) interact with medium have many remarkable properties with its unique azimuthal phase, showing many potential applications in high capacity information processing, high precision measurement etc. The dephasing mechanics of optical fields with OAM in an interface between light and matter plays a vital role in many areas of physics. In this work, we study the transverse azimuthal dephasing of OAM spin wave in a hot atomic gas via OAM storage. The transverse azimuthal phase difference between the control and probe beams is mapped onto the spin wave, which essentially results in dephasing of atomic spin wave. The dephasing of OAM spin wave can be controlled by the parameters of OAM topological charge and beam waist. Our results are helpful for studying OAM light interaction with matter, maybe hold a promise in OAM-based quantum information processing.

  17. Evidence for Proportionate Partition Between the Magnetic Field and Hot Gas in Turbulent Cassiopeia A

    CERN Document Server

    Keohane, J W; Petre, R

    1998-01-01

    We present a deep X-ray observation of the young Galactic supernova remnant Cas A, acquired with the ROSAT High Resolution Imager. This high dynamic range (232 ks) image reveals low-surface-brightness X-ray structure, which appears qualitatively similar to corresponding radio features. We consider the correlation between the X-ray and radio morphologies and its physical implications. After correcting for the inhomogeneous absorption across the remnant, we performed a point by point (4" resolution) surface brightness comparison between the X-ray and radio images. We find a strong (r = 0.75) log-log correlation, implying an overall relationship of $\\log(\\Sigma_{_{\\rm X-ray}}) \\propto (2.21\\pm0.05) \\times \\log(\\Sigma_{_{\\rm radio}})$. This is consistent with proportionate partition (and possibly equipartition) between the local magnetic field and the hot gas --- implying that Cas A's plasma is fully turbulent and continuously amplifying the magnetic field.

  18. Investigation of austenitic alloys for advanced heat recovery and hot-gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    Materials properties were collected for the design and construction of structural components for use in advanced heat recovery and hot gas cleanup systems. Alloys systems included 9Cr-1Mo-V steel, modified 316 stainless steel, modified type 310 stainless steel, modified 20Cr-25Ni-Nb stainless steel, and modified alloy 800. Experimental work was undertaken to expand the databases for potentially useful alloys. Types of testing included creep, stress-rupture, creep-crack growth, fatigue, and post-exposure short-time tensile tests. Because of the interest in relatively inexpensive alloys for service at 700 C and higher, research emphasis was placed on a modified type 310 stainless steel and a modified 20Cr-25Ni-Nb stainless steel. Both steels were found to have useful strength to 925 C with good weldability and ductility.

  19. Investigation of austenitic alloys for advanced heat recovery and hot gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.; Ren, W. [Oak Ridge National Lab., TN (United States)

    1995-08-01

    Alloys for design and construction of structural components needed to contain process streams and provide internal structures in advanced heat recovery and hot gas cleanup systems were examined. Emphasis was placed on high-strength, corrosion-resistant alloys for service at temperatures above 1000 {degrees}F (540{degrees}C). Data were collected that related to fabrication, joining, corrosion protection, and failure criteria. Alloys systems include modified type 310 and 20Cr-25Ni-Nb steels and sulfidation-resistance alloys HR120 and HR160. Types of testing include creep, stress-rupture, creep crack growth, fatigue, and post-exposure short-time tensile. Because of the interest in relatively inexpensive alloys for high temperature service, a modified type 310 stainless steel was developed with a target strength of twice that for standard type 310 stainless steel.

  20. Investigation of austenitic alloys for advanced heat recovery and hot gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.; Ren, W. [Oak Ridge National Lab., TN (United States)

    1996-08-01

    Materials properties were collected for the design and construction of structural components for use in advanced heat recovery and hot gas cleanup systems. Alloys systems included 9Cr-1Mo-V steel, modified 316 stainless steel, modified type 310 stainless steel, modified 20Cr-25Ni-Nb stainless steel, modified alloy 800, and two sulfidation resistant alloys: HR160 and HR120. Experimental work was undertaken to expand the databases for potentially useful alloys. Types of testing included creep, stress-rupture, creep-crack growth, fatigue, and post-exposure short-time tensile tests. Because of the interest in relatively inexpensive alloys for service at 700{degrees}C and higher, research emphasis was placed on a modified type 310 stainless steel and a modified 20Cr-25Ni-Nb stainless steel. Both steels were found to have useful strength to 925{degrees}C with good weldability and ductility.

  1. Mechanical behavior of ceramic composite hot-gas filters after exposure to severe environments

    Energy Technology Data Exchange (ETDEWEB)

    Pysher, D.J.; Weaver, B.L.; Smith, R.G. [Ceramic Technology Center, St. Paul, MN (United States)] [and others

    1995-08-01

    A novel type of hot-gas filter based on a ceramic fiber reinforced ceramic matrix has been developed, as reported at previous Fossil Energy Materials Conferences, through research activities at Oak Ridge National Laboratory (ORNL) and at the 3M Company. Simulated testing has been done at the Westinghouse Science and Technology Center. This filter technology has been extended to full size, 60 mm OD by 1.5 meter long candle filters and a commercially viable process for producing the filters has been developed filters are undergoing testing and demonstration use throughout the world for applications in pressurized fluidized-bed combustion (PFBC) and integrated gasification combined cycle (IGCC) plants. Demonstration tests of this ceramic composite filter along with other filters are in progress at the Tidd PFBC plant Mechanical tests were performed on the 3 M brand Ceramic Composite Candle Filter after exposure to various corrosive environments in order to assess its ability to function as a hot gas filter in coal-fired applications. Due to the different construction of ceramic composite filters and the thin composite wall versus the typical thick-walled monolithic filter, standard mechanical property tests had to be refined or modified to accurately determine the filters properties. These tests and filter property results will be described Longitudinal tensile and diametral O-ring compression tests were performed on as-produced candle filters as well as on filters which had been exposed to various environments. The exposures were for 1000 hrs at 850{degrees}C in wet air, in wet air containing Na{sub 2}CO{sub 3}, and in wet air containing NaCl. In addition, a filter which bad been coated with ash (Old Grimethorpe) was exposed to wet air at 850{degrees}C for 1000 hours.

  2. Effect of the Sequence of the Thermoelectric Generator and the Three-Way Catalytic Converter on Exhaust Gas Conversion Efficiency

    Science.gov (United States)

    Su, Chuqi; Tong, Naiqiang; Xu, Yuman; Chen, Shan; Liu, Xun

    2013-07-01

    The potential for thermoelectric exhaust heat recovery in vehicles has increased with recent improvements in the efficiency of thermoelectric generators (TEGs). The problem with using thermoelectric generators for vehicle applications is whether the device is compatible with the original vehicle exhaust system, which determines the quality of the exhaust gas treatment and the realization of energy conservation and emission reduction. Based on ANSYS CFX simulation analysis of the impact of two positional relationships between the TEG and three-way catalytic converter in the exhaust system on the working efficiency of both elements, it is concluded that the layout with the front three-way catalytic converter has an advantage over the other layout mode under current conditions. New ideas for an improvement program are proposed to provide the basis for further research.

  3. Chemical hot gas purification for biomass gasification processes; Chemische Heissgasreinigung bei Biomassevergasungsprozessen

    Energy Technology Data Exchange (ETDEWEB)

    Stemmler, Michael

    2010-07-01

    The German government decided to increase the percentage of renewable energy up to 20 % of all energy consumed in 2020. The development of biomass gasification technology is advanced compared to most of the other technologies for producing renewable energy. So the overall efficiency of biomass gasification processes (IGCC) already increased to values above 50 %. Therefore, the production of renewable energy attaches great importance to the thermochemical biomass conversion. The feedstock for biomass gasification covers biomasses such as wood, straw and further energy plants. The detrimental trace elements released during gasification of these biomasses, e.g. KCl, H{sub 2}S and HCl, cause corrosion and harm downstream devices. Therefore, gas cleaning poses an especial challenge. In order to improve the overall efficiency this thesis aims at the development of gas cleaning concepts for the allothermic, water blown gasification at 800 C and 1 bar (Guessing-Process) as well as for the autothermic, water and oxygen blown gasification at 950 C and 18 bar (Vaernamo-Process). Although several mechanisms for KCl- and H{sub 2}S-sorption are already well known, the achievable reduction of the contamination concentration is still unknown. Therefore, calculations on the produced syngas and the chemical hot gas cleaning were done with a thermodynamic process model using SimuSage. The syngas production was included in the calculations because the knowledge of the biomass syngas composition is very limited. The results of these calculations prove the dependence of syngas composition on H{sub 2}/C-ratio and ROC (Relative Oxygen Content). Following the achievable sorption limits were detected via experiments. The KCl containing syngases were analysed by molecular beam mass spectrometry (MBMS). Furthermore, an optimised H{sub 2}S-sorbent was developed because the examined sorbents exceeded the sorption limit of 1 ppmv. The calculated sorption limits were compared to the limits

  4. Numerical Modeling of Reactive Multiphase Flow for FCC and Hot Gas Desulfurization Circulating Fluidized Beds

    Energy Technology Data Exchange (ETDEWEB)

    None

    2005-07-01

    This work was carried out to understand the behavior of the solid and gas phases in a CFB riser. Only the riser is modeled as a straight pipe. A model with linear algebraic approximation to solids viscosity of the form, {musubs} = 5.34{epsisubs}, ({espisubs} is the solids volume fraction) with an appropriate boundary condition at the wall obtained by approximate momentum balance solution at the wall to acount for the solids recirculation is tested against experimental results. The work done was to predict the flow patterns in the CFB risers from available experimental data, including data from a 7.5-cm-ID CFB riser at the Illinois Institute of Technology and data from a 20.0-cm-ID CFB riser at the Particulate Solid Research, Inc., facility. This research aims at modeling the removal of hydrogen sulfide from hot coal gas using zinc oxide as the sorbent in a circulating fluidized bed and in the process indentifying the parameters that affect the performance of the sulfidation reactor. Two different gas-solid reaction models, the unreacted shrinking core (USC) and the grain model were applied to take into account chemical reaction resistances. Also two different approaches were used to affect the hydrodynamics of the process streams. The first model takes into account the effect of micro-scale particle clustering by adjusting the gas-particle drag law and the second one assumes a turbulent core with pseudo-steady state boundary condition at the wall. A comparison is made with experimental results.

  5. Development of selective catalytic oxidation (SCO) for NH{sub 3} and HCN removal from gasification gas; Selektiivisen katalyyttisen hapetusprosessin (SCO) kehittaeminen kaasutuskaasun NH{sub 3}:n ja HCN:n poistoon

    Energy Technology Data Exchange (ETDEWEB)

    Leppaelahti, J.; Koljonen, T.; Heiskanen, K. [VTT Energy, Espoo (Finland)

    1997-10-01

    In gasification, reactive nitrogen compounds (mainly NH{sub 3} and HCN) are formed from fuel nitrogen. If the gas containing NH{sub 3} is burned, a high NO{sub x} emission may be formed. The content of nitrogen compounds of the hot gasification gas could be reduced in Selective Catalytic Oxidation (SCO) process. In this process small amounts of reactive oxidisers are injected into the gas in order to convert NH{sub 3} to N{sub 2}. The utilization of SCO process together with low NO{sub x} burners in advanced gasification power stations might offer an alternative for flue gas treatment technologies like SCR (Selective Catalytic Reduction). In the earlier research, conditions were found, where oxidizers reacted selectively with ammonia in the gasification gas. Highest ammonia reduction took place in the aluminium oxide bed in the presence of NO and O{sub 2}. The aim of this study is to examine the reaction mechanism in order to be able to further evaluate the development possibilities of this kind process. The effect of composition and the amount of added oxidizer, the content of combustible gas components, space velocity, pressure and temperature will be studied. The experiments are carried out with the laboratory scale high pressure flow reactor of VTT Energy. Kinetic modelling of the experimental results is carried out in co-operation with the combustion chemistry group of Aabo Akademi. The aim of the modelling work is to bring insight to the gas-phase reactions that are important for the SCO-process. (orig.)

  6. Simultaneous probing of bulk liquid phase and catalytic gas-liquid-solid interface under working conditions using attenuated total reflection infrared spectroscopy

    International Nuclear Information System (INIS)

    Design and performance of a reactor set-up for attenuated total reflection infrared (ATR-IR) spectroscopy suitable for simultaneous reaction monitoring of bulk liquid and catalytic solid-liquid-gas interfaces under working conditions are presented. As advancement of in situ spectroscopy an operando methodology for gas-liquid-solid reaction monitoring was developed that simultaneously combines catalytic activity and molecular level detection at the catalytically active site of the same sample. Semi-batch reactor conditions are achieved with the analytical set-up by implementing the ATR-IR flow-through cell in a recycle reactor system and integrating a specifically designed gas feeding system coupled with a bubble trap. By the use of only one spectrometer the design of the new ATR-IR reactor cell allows for simultaneous detection of the bulk liquid and the catalytic interface during the working reaction. Holding two internal reflection elements (IRE) the sample compartments of the horizontally movable cell are consecutively flushed with reaction solution and pneumatically actuated, rapid switching of the cell (<1 s) enables to quasi simultaneously follow the heterogeneously catalysed reaction at the catalytic interface on a catalyst-coated IRE and in the bulk liquid on a blank IRE. For a complex heterogeneous reaction, the asymmetric hydrogenation of 2,2,2-trifluoroacetophenone on chirally modified Pt catalyst the elucidation of catalytic activity/enantioselectivity coupled with simultaneous monitoring of the catalytic solid-liquid-gas interface is shown. Both catalytic activity and enantioselectivity are strongly dependent on the experimental conditions. The opportunity to gain improved understanding by coupling measurements of catalytic performance and spectroscopic detection is presented. In addition, the applicability of modulation excitation spectroscopy and phase-sensitive detection are demonstrated

  7. KINETICS OF HOT-GAS DESULFURIZATION SORBENTS FOR TRANSPORT REACTORS; ANNUAL

    International Nuclear Information System (INIS)

    Hot-gas desulfurization for the integrated gasification combined cycle (IGCC) process has been investigated by many researchers to remove effectively hydrogen sulfide with various metal oxide sorbents at elevated temperatures. Various metal oxide sorbents are formulated with metal oxides such as Fe, Co, Zn, and Ti. Initial reaction kinetics of formulated sorbents with hydrogen sulfide is studied in the presence of various amounts of moisture and hydrogen at various reaction temperatures. The objectives of this research are to study initial reaction kinetics for a sorbent-hydrogen sulfide heterogeneous reaction system, to investigate effects of concentrations of hydrogen sulfide, hydrogen, and moisture on dynamic absorption of H(sub 2)S into sorbents, and to evaluate effects of temperature and sorbent amounts on dynamic absorption of H(sub 2)S into sorbents. Experimental data on initial reaction kinetics of hydrogen sulfide with metal oxide sorbents were obtained with a 0.83-cm(sup 3) differential reactor. The reactivity of MCRH-67 was examined in this report. This sorbent was obtained from the Research Triangle Institute (RTI). The sorbent in the form of 130 mm particles are reacted with 18000-ppm hydrogen sulfide at 350-525 C. The range of space time of reaction gas mixtures is 0.069-0.088 s. The range of reaction duration is 4-180 s

  8. Influence of rarefaction on the flow dynamics of a stationary supersonic hot-gas expansion.

    Science.gov (United States)

    Abbate, G; Kleijn, C R; Thijsse, B J; Engeln, R; van de Sanden, M C M; Schram, D C

    2008-03-01

    The gas dynamics of a stationary hot-gas jet supersonically expanding into a low pressure environment is studied through numerical simulations. A hybrid coupled continuum-molecular approach is used to model the flow field. Due to the low pressure and high thermodynamic gradients, continuum mechanics results are doubtful, while, because of its excessive time expenses, a full molecular method is not feasible. The results of the hybrid coupled continuum-molecular approach proposed have been successfully validated against experimental data by R. Engeln [Plasma Sources Sci. Technol. 10, 595 (2001)] obtained by means of laser induced fluorescence. Two main questions are addressed: the necessity of applying a molecular approach where rarefaction effects are present in order to correctly model the flow and the demonstration of an invasion of the supersonic part of the flow by background particles. A comparison between the hybrid method and full continuum simulations demonstrates the inadequacy of the latter, due to the influence of rarefaction effects on both velocity and temperature fields. An analysis of the particle velocity distribution in the expansion-shock region shows clear departure from thermodynamic equilibrium and confirms the invasion of the supersonic part of the flow by background particles. A study made through particles and collisions tracking in the supersonic region further proves the presence of background particles in this region and explains how they cause thermodynamic nonequilibrium by colliding and interacting with the local particles.

  9. High temperature corrosion of advanced ceramic materials for hot-gas filters and heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Kupp, E.R.; Trubelja, M.F.; Spear, K.E.; Tressler, R.E. [Pennsylvania State Univ., University Park, PA (United States)

    1995-08-01

    Experimental corrosion studies of hot gas filter materials and heat exchanger materials in oxidizing combustion environments have been initiated. Filter materials from 3M Co. and DuPont Lanxide Composites Inc. are being tested over a range of temperatures, times and gas flows. It has been demonstrated that morphological and phase changes due to corrosive effects occur after exposure of the 3M material to a combustion environment for as little as 25 hours at 800{degrees}C. The study of heat exchanger materials has focused on enhancing the corrosion resistance of DuPont Lanxide Dimox{trademark} composite tubes by adding chromium to its surfaces by (1) heat treatments in a Cr{sub 2}O{sub 3} powder bed, or (2) infiltrating surface porosity with molten chromium nitrate. Each process is followed by a surface homogenization at 1500{degrees}C. The powder bed method has been most successful, producing continuous Cr-rich layers with thicknesses ranging from 20 to 250 {mu}m. As-received and Cr-modified DuPont Lanxide Dimox{trademark} samples will be reacted with commonly encountered coal-ash slags to determine the Cr effects on corrosion resistance.

  10. The scatter and evolution of the global hot gas properties of simulated galaxy cluster populations

    CERN Document Server

    Brun, Amandine M C Le; Schaye, Joop; Ponman, Trevor J

    2016-01-01

    We use the cosmo-OWLS suite of cosmological hydrodynamical simulations to investigate the scatter and evolution of the global hot gas properties of large simulated populations of galaxy groups and clusters. Our aim is to compare the predictions of different physical models and to explore the extent to which commonly-adopted assumptions in observational analyses (e.g. self-similar evolution) are violated. We examine the relations between (true) halo mass and the X-ray temperature, X-ray luminosity, gas mass, Sunyaev-Zel'dovich (SZ) flux, the X-ray analogue of the SZ flux ($Y_X$) and the hydrostatic mass. For the most realistic models, which include AGN feedback, the slopes of the various mass-observable relations deviate substantially from the self-similar ones, particularly at late times and for low-mass clusters. The amplitude of the mass-temperature relation shows negative evolution with respect to the self-similar prediction (i.e. slower than the prediction) for all models, driven by an increase in non-the...

  11. Study on Influence to Waste Water Treatment Plant’s Sludge by Low-carbon Catalytic Combustion Furnace of Natural Gas

    Directory of Open Access Journals (Sweden)

    Ren TianQi

    2016-01-01

    Full Text Available There are two parts in this experiment. One of is about the concentration of Variation of exhaust gas while heating sludge of waste water treatment plant. The other one is about introduce the problems of the traditional incineration processes of sludge of waste water treatment as compared between the sludge heated by natural gas catalytic combustion furnace and the tradition’s. We can see that natural gas low-carbon catalytic combustion furnace realize the near-zero emission of contaminates.

  12. Catalytic modification of conventional SOFC anodes with a view to reducing their activity for direct internal reforming of natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Boder, M.; Dittmeyer, R. [Research Group Technical Chemistry, Karl-Winnacker-Institut, DECHEMA e.V., Theodor-Heuss-Allee 25, D-60486 Frankfurt (Germany)

    2006-04-18

    When using natural gas as fuel for the solid oxide fuel cell (SOFC), direct internal reforming lowers the requirement for cell cooling and, theoretically, offers advantages with respect to capital cost and efficiency. The high metal content of a nickel/zirconia anode and the high temperature, however, cause the endothermic reforming reaction to take place very fast. The resulting drop of temperature at the inlet produces thermal stresses, which may lower the system efficiency and limit the stack lifetime. To reduce the reforming rate without lowering the electrochemical activity of the cell, a wet impregnation procedure for modifying conventional cermets by coverage with a less active metal was developed. As the coating material copper was chosen. Copper is affordable, catalytically inert for the reforming reaction and exhibits excellent electronic conductivity. The current density-voltage characteristics of the modified units showed that it is possible to maintain a good electrochemical performance of the cells despite the catalytic modification. A copper to nickel ratio of 1:3 resulted in a strong diminution of the catalytic reaction rate. This indicates that the modification could be a promising method to improve the performance of solid oxide fuel cells with direct internal reforming of hydrocarbons. (author)

  13. The temperature of hot gas in galaxies and clusters: baryons dancing to the tune of dark matter

    CERN Document Server

    Hansen, Steen H; Romano-Diaz, Emilio; Hoffman, Yehuda; Brüggen, Marcus; Scannapieco, Evan; Stinson, Greg S

    2010-01-01

    The temperature profile of hot gas in galaxies and galaxy clusters is largely determined by the depth of the total gravitational potential and thereby by the dark matter (DM) distribution. We use high-resolution hydrodynamical simulations of galaxy formation to derive a surprisingly simple relation between the gas temperature and DM properties. We show that this relation holds not just for galaxy clusters but also for equilibrated and relaxed galaxies at radii beyond the central stellar-dominated region of typically a few kpc. It is then clarified how a measurement of the temperature and density of the hot gas component can lead to an indirect measurement of the DM velocity anisotropy in galaxies. We also study the temperature relation for galaxy clusters in the presence of self-regulated, recurrent active galactic nuclei (AGN), and demonstrate that this temperature relation even holds outside the inner region of 30 kpc in clusters with an active AGN.

  14. THE TEMPERATURE OF HOT GAS IN GALAXIES AND CLUSTERS: BARYONS DANCING TO THE TUNE OF DARK MATTER

    International Nuclear Information System (INIS)

    The temperature profile of hot gas in galaxies and galaxy clusters is largely determined by the depth of the total gravitational potential and thereby by the dark matter (DM) distribution. We use high-resolution hydrodynamical simulations of galaxy formation to derive a surprisingly simple relation between the gas temperature and DM properties. We show that this relation holds not just for galaxy clusters but also for equilibrated and relaxed galaxies at radii beyond the central stellar-dominated region of typically a few kpc. It is then clarified how a measurement of the temperature and density of the hot gas component can lead to an indirect measurement of the DM velocity anisotropy in galaxies. We also study the temperature relation for galaxy clusters in the presence of self-regulated, recurrent active galactic nuclei (AGNs), and demonstrate that this temperature relation even holds outside the inner region of ∼30 kpc in clusters with an active AGN.

  15. Dynamics and mechanisms of catalytic processes and hot chemistry. Progress report, March 1, 1982-February 28, 1983

    International Nuclear Information System (INIS)

    The characterization of photo-assistance and photochemical changes in reactions catalyzed with Wilkinson's Catalyst has been extended to include kinetic analysis and a preliminary determination of the main features in the action spectrum. Photo-assistance in olefin hydrogenation and photochemical transformation of the catalyst to promote olefin isomerization occur over distinct spectral regions. Kinetic analysis of the yield data indicates the metastable isomerization catalyst formed is long lived and operates with a substantial turnover number and corresponding high quantum yield. Products from the new reaction between sulfur dioxide and hexamethyldisilazane discovered in this laboratory were further characterized. This reaction represents a facile silylation process in the absence of acidic hydrogen which produces synthetically and analytically useful materials. The new solid product, ammonium trimethylsilyl sulfite, was studied in detail. This ionic compound has an unusually high vapor pressure at 250C, and the gas phase components in equilibrium with the solid were identified by FT-1R methods. A patent filed by DOE in this area is pending. The dynamical model developed in this laboratory to describe recoil processes has been applied to investigations of the moderated nuclear recoil technique for measuring thermal rate constants. The general applicability and constraints of the method have been identified from the results obtained in several model systems. The recoil spectrum for chlorine-36 produced via the (n,γ) process has been calculated from the prompt gamma ray spectrum and compared with that of chlorine-38 previously reported from this laboratory. 3 figures, 4 tables

  16. Thermodynamic analysis of a process for producing high-octane gasoline components from catalytic cracking gas

    Science.gov (United States)

    Ismailova, Z. R.; Pirieva, Kh. B.; Kasimov, A. A.; Dzhamalova, S. A.; Gadzhizade, S. M.; Nuriev, Sh. A.; Zeinalova, S. Kh.; Dzhafarov, R. P.

    2016-03-01

    The results from a thermodynamic analysis of high-octane gasoline component production from catalytic cracking gases using zeolite catalyst OMNIKAT-210P modified with Ni, Co, Cr are presented. The equilibrium constants of the reactions assumed to occur in this process are calculated, along with the equilibrium yield of the reactions.

  17. Auto-thermal reforming of biomass raw fuel gas to syngas in a novel reformer: Promotion of hot-electron

    International Nuclear Information System (INIS)

    Highlights: • A novel reformer with porous ceramic tube circled by electric wire was designed. • The temperature uniformities along diameter and axial direction were measured. • The auto-thermal reforming of model and real biomass fuel gas was performed. • The hot electron promoted biomass fuel gas elimination mechanism was proposed. - Abstract: A novel reformer with porous ceramic oxygen distribution tube circled by electric wire for inspiring hot electron was designed for auto-thermal reforming of biomass raw fuel gas to produce syngas (H2 + CO). The temperature of auto-thermal reformer was nearly uniform due to the excellent performance of partial oxygenation reaction in the reformer with porous ceramic tube for oxygen partitioning. The hot-electron inspired by electric wire promoted the cracking of biomass tar to form radical species, which were converted effectively to syngas over nickel based catalyst. The hot-electron also played an essential role in decreasing coke deposition on the surface of nickel based catalyst, which prolonged the lifetime of the reforming catalyst

  18. Galaxy formation with local photoionization feedback - II. Effect of X-ray emission from binaries and hot gas

    Science.gov (United States)

    Kannan, R.; Vogelsberger, M.; Stinson, G. S.; Hennawi, J. F.; Marinacci, F.; Springel, V.; Macciò, A. V.

    2016-05-01

    We study how X-rays from stellar binary systems and the hot intracluster medium (ICM) affect the radiative cooling rates of gas in galaxies. Our study uses a novel implementation of gas cooling in the moving-mesh hydrodynamics code AREPO. X-rays from stellar binaries do not affect cooling at all as their emission spectrum is too hard to effectively couple with galactic gas. In contrast, X-rays from the ICM couple well with gas in the temperature range 104-106 K. Idealized simulations show that the hot halo radiation field has minimal impact on the dynamics of cooling flows in clusters because of the high virial temperature ( ≳ 107 K), making the interaction between the gas and incident photons very ineffective. Satellite galaxies in cluster environments, on the other hand, experience a high radiation flux due to the emission from the host halo. Low-mass satellites ( ≲ 1012 M⊙) in particular have virial temperatures that are exactly in the regime where the effect of the radiation field is maximal. Idealized simulations of satellite galaxies including only the effect of host halo radiation (no ram pressure stripping or tidal effects) fields show a drastic reduction in the amount of cool gas formed (˜40 per cent) on a short time-scale of about 0.5 Gyr. A galaxy merger simulation including all the other environmental quenching mechanisms, shows about 20 per cent reduction in the stellar mass of the satellite and about ˜30 per cent reduction in star formation rate after 1 Gyr due to the host hot halo radiation field. These results indicate that the hot halo radiation fields potentially play an important role in quenching galaxies in cluster environments.

  19. Study on Indirect Measuring Technology of EAF Steelmaking Decarburization Rate by Off-gas Analysis Technique in Hot State Experiment

    Science.gov (United States)

    Dong, Kai; Liu, Wenjuan; Zhu, Rong

    2015-10-01

    In this paper, measurement method of EAF Steelmaking decarburization rate is studied. Because of the fuel gas blown and air mixed, the composition of hot temperature off-gas is measurand unreally, and the flow rate is unknown too, the direct measurement of EAF decarburization rate by furnace gas analysis is unrealized. Firstly, the off-gas generation process is discussed. After that, dynamic concentration of CO2, CO, and O2 in off-gas and EAF oxygen supply rate are monitored in real time. Finally, the concentration and volume flow rate of off-gas are obtained to measure the EAF decarburization rate indirectly. The results of the hot state experiments show that the decarburization rate in oxidization step can reach up to about 0.53 mol/s, and the forecasting carbon concentration is 1.14% corresponding to the average carbon concentration (1.43%) in finial metal samples. The measurement of decarburization rate by off-gas analysis technique can be reasonable in EAF production process.

  20. Catalytic hydrothermal gasification of biomass for the production of synthetic natural gas[Dissertation 17100

    Energy Technology Data Exchange (ETDEWEB)

    Waldner, M. H.

    2007-07-01

    Energy from biomass is a CO{sub 2} neutral, sustainable form of energy. Anaerobic digestion is an established technology for converting biomass to biogas, which contains around 60% methane, besides CO{sub 2} and various contaminants. Most types of biomass contain material that cannot be digested; in woody biomass, this portion is particularly high. Therefore, conventional anaerobic digestion is not suited for the production of biogas from woody biomass. While wood is already being converted to energy by conventional thermal methods (gasification with subsequent methanation), dung, manure, and sewage sludge represent types of biomass whose energy potential remains largely untapped (present energetic use of manure in Switzerland: 0.4%). Conventional gas phase processes suffer from a low efficiency due to the high water content of the feed (enthalpy of vaporization). An alternative technology is the hydrothermal gasification: the water contained within the biomass serves as reaction medium, which at high pressures of around 30 MPa turns into a supercritical fluid that exhibits apolar properties. Under these conditions, tar precursors, which cause significant problems in conventional gasification, can be solubilized and gasified. The need to dry the biomass prior to gasification is obsolete, and as a consequence high thermal process efficiencies (65 - 70%) are possible. Due to their low solubility in supercritical water, the inorganics that are present in the biomass (up to 20 wt % of the dry matter of manure) can be separated and further used as fertilizer. The biomass is thus not only converted into an energy carrier, but it allows valuable substances contained in the biomass to be extracted and re-used. Furthermore, the process can be used for aqueous waste stream destruction. The aim of this project at the Paul Scherrer Institute was to develop a catalytic process that demonstrates the gasification of wet biomass to synthetic natural gas (SNG) in a continuously

  1. Removal of P4, PH3 and H2S from Yellow Phosphoric Tail Gas by a Catalytic Oxidation Process

    Institute of Scientific and Technical Information of China (English)

    NingPing; Hans-JoergBart; MaLiping; WangXueqian

    2004-01-01

    Yellow phosphorus tail gas is a resource used to produce bulk chemicals, such as formates, oxalates, and methanol after its pretreatment and purification. In this study, catalytic oxidation of phosphorus and hydrogen sulfide in yellow phosphorus tail gas was investigated on an ordinary activated carbon (OAC) and a home-made catalyst KU2. The adsorption characteristics of phosphorus and hydrogen sulfide on the catalysts were studied in a fixed-bed system at different temperatures between 20℃ and 140℃ at atmospheric pressure. Both KU2 and OAC are proved to be effective catalysts in the catalytic oxidation process (COP) for H2S and PH3 removal. Purification efficiency increased with the increase of temperature and oxygen concentration in yellow phosphorus tail gases. Under optimized operation conditions, the product gases with a content of hydrogen sulfide <5mg/m3 and total phosphorus <5mg/m3 were obtained by using the COP process. Deactivated catalysts could be restored to the original activated state, even after several regenerations. A mathematical model was developed to simulate the experimental results and the mass transport coefficient from the experiment was evaluated. Good agreement between the experimental breakthrough curves and the model predictions was observed.

  2. Volatile emissions and gas geochemistry of Hot Spring Basin, Yellowstone National Park, USA

    Science.gov (United States)

    Werner, C.; Hurwitz, S.; Evans, William C.; Lowenstern, J. B.; Bergfeld, D.; Heasler, H.; Jaworowski, C.; Hunt, A.

    2008-01-01

    We characterize and quantify volatile emissions at Hot Spring Basin (HSB), a large acid-sulfate region that lies just outside the northeastern edge of the 640??ka Yellowstone Caldera. Relative to other thermal areas in Yellowstone, HSB gases are rich in He and H2, and mildly enriched in CH4 and H2S. Gas compositions are consistent with boiling directly off a deep geothermal liquid at depth as it migrates toward the surface. This fluid, and the gases evolved from it, carries geochemical signatures of magmatic volatiles and water-rock reactions with multiple crustal sources, including limestones or quartz-rich sediments with low K/U (or 40*Ar/4*He). Variations in gas chemistry across the region reflect reservoir heterogeneity and variable degrees of boiling. Gas-geothermometer temperatures approach 300????C and suggest that the reservoir feeding HSB is one of the hottest at Yellowstone. Diffuse CO2 flux in the western basin of HSB, as measured by accumulation-chamber methods, is similar in magnitude to other acid-sulfate areas of Yellowstone and is well correlated to shallow soil temperatures. The extrapolation of diffuse CO2 fluxes across all the thermal/altered area suggests that 410 ?? 140??t d- 1 CO2 are emitted at HSB (vent emissions not included). Diffuse fluxes of H2S were measured in Yellowstone for the first time and likely exceed 2.4??t d- 1 at HSB. Comparing estimates of the total estimated diffuse H2S emission to the amount of sulfur as SO42- in streams indicates ~ 50% of the original H2S in the gas emission is lost into shallow groundwater, precipitated as native sulfur, or vented through fumaroles. We estimate the heat output of HSB as ~ 140-370??MW using CO2 as a tracer for steam condensate, but not including the contribution from fumaroles and hydrothermal vents. Overall, the diffuse heat and volatile fluxes of HSB are as great as some active volcanoes, but they are a small fraction (1-3% for CO2, 2-8% for heat) of that estimated for the entire

  3. High-temperature turbine technology program hot-gas path development test. Part II. Testing

    Energy Technology Data Exchange (ETDEWEB)

    Horner, M.W.

    1982-03-01

    This topical report of the US Department of Energy High-Temperature Turbine Technology (DOE-HTTT) Phase II program presents the results of testing full-scale water-cooled first-stage and second-stage turbine nozzles at design temperature and pressure to verify that the designs are adequate for operation in a full-scale turbine environment. Low-cycle fatigue life of the nozzles was demonstrated by subjecting cascade assemblies to several hundred simulated startup/shutdown turbine cycles. This testing was accomplished in the Hot-Gas Path Development Test Stand (HGPDTS), which is capable of evaluating full-scale combustion and turbine nozzle components. A three-throat cascade of the first-stage turbine nozzle was successfully tested at a nozzle inlet gas temperature of 2630/sup 0/F and a nozzle inlet pressure of 11.3 atmospheres. In addition to steady-state operation at the design firing temperature, the nozzle cascade was exposed to a simulated startup/shutdown turbine cycle by varying the firing temperature. A total of 42 h at the design point and 617 thermal cycles were accumulated during the test periods. First-stage nozzle test results show that measured metal and coolant temperatures correspond well to the predicted design values. This nozzle design has been shown to be fully satisfactory for the application (2600/sup 0/F), with growth capability to 3000/sup 0/F firing temperature. A post-test metallurgical examination of sectioned portions of the tested nozzles shows a totally bonded structure, confirming the test results and attesting to the successful performance of water-cooled composite nozzle hardware.

  4. Preliminary design for hot dirty-gas control-valve test facility. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    This report presents the results of a preliminary design and cost estimating effort for a facility for the testing of control valves in Hot Dirty Gas (HDGCV) service. This design was performed by Mittelhauser Corporation for the United States Department of Energy's Morgantown Energy Technology Center (METC). The objective of this effort was to provide METC with a feasible preliminary design for a test facility which could be used to evaluate valve designs under simulated service conditions and provide a technology data base for DOE and industry. In addition to the actual preliminary design of the test facility, final design/construction/operating schedules and a facility cost estimate were prepared to provide METC sufficient information with which to evaluate this design. The bases, assumptions, and limitations of this study effort are given. The tasks carried out were as follows: METC Facility Review, Environmental Control Study, Gas Generation Study, Metallurgy Review, Safety Review, Facility Process Design, Facility Conceptual Layout, Instrumentation Design, Cost Estimates, and Schedules. The report provides information regarding the methods of approach used in the various tasks involved in the completion of this study. Section 5.0 of this report presents the results of the study effort. The results obtained from the above-defined tasks are described briefly. The turnkey cost of the test facility is estimated to be $9,774,700 in fourth quarter 1979 dollars, and the annual operating cost is estimated to be $960,000 plus utilities costs which are not included because unit costs per utility were not available from METC.

  5. High temperature corrosion of advanced ceramic materials for hot gas filters and heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Crossland, C.E.; Shelleman, D.L.; Spear, K.E. [Pennsylvania State Univ., University Park, PA (United States)] [and others

    1996-08-01

    A vertical flow-through furnace has been built to study the effect of corrosion on the morphology and mechanical properties of ceramic hot gas filters. Sections of 3M Type 203 and DuPont Lanxide SiC-SiC filter tubes were sealed at one end and suspended in the furnace while being subjected to a simulated coal combustion environment at 870{degrees}C. X-ray diffraction and electron microscopy is used to identify phase and morphology changes due to corrosion while burst testing determines the loss of mechanical strength after exposure to the combustion gases. Additionally, a thermodynamic database of gaseous silicon compounds is currently being established so that calculations can be made to predict important products of the reaction of the environment with the ceramics. These thermodynamic calculations provide useful information concerning the regimes where the ceramic may be degraded by material vaporization. To verify the durability and predict lifetime performance of ceramic heat exchangers in coal combustion environments, long-term exposure testing of stressed (internally pressurized) tubes must be performed in actual coal combustion environments. The authors have designed a system that will internally pressurize 2 inch OD by 48 inch long ceramic heat exchanger tubes to a maximum pressure of 200 psi while exposing the outer surface of the tubes to coal combustion gas at the Combustion and Environmental Research Facility (CERF) at the Pittsburgh Energy and Technology Center. Water-cooled, internal o-ring pressure seals were designed to accommodate the existing 6 inch by 6 inch access panels of the CERF. Tubes will be exposed for up to a maximum of 500 hours at temperatures of 2500 and 2600{degrees}F with an internal pressure of 200 psi. If the tubes survive, their retained strength will be measured using the high temperature tube burst test facility at Penn State University. Fractographic analysis will be performed to identify the failure source(s) for the tubes.

  6. Hot, metastable hydronium ion in the Galactic centre: formation pumping in X-ray-irradiated gas?

    Science.gov (United States)

    Lis, Dariusz C; Schilke, Peter; Bergin, Edwin A; Emprechtinger, Martin

    2012-11-13

    With a 3.5 m diameter telescope passively cooled to approximately 80 K, and a science payload comprising two direct detection cameras/medium resolution imaging spectrometers (PACS and SPIRE) and a very high spectral resolution heterodyne spectrometer (HIFI), the Herschel Space Observatory is providing extraordinary observational opportunities in the 55-670 μm spectral range. HIFI has opened for the first time to high-resolution spectroscopy the submillimetre band that includes the fundamental rotational transitions of interstellar hydrides, the basic building blocks of astrochemistry. We discuss a recent HIFI discovery of metastable rotational transitions of the hydronium ion (protonated water, H(3)O(+)), with rotational level energies up to 1200 K above the ground state, in absorption towards Sagittarius B2(N) in the Galactic centre. Hydronium is an important molecular ion in the oxygen chemical network. Earlier HIFI observations have indicated a general deficiency of H(3)O(+) in the diffuse gas in the Galactic disc. The presence of hot H(3)O(+) towards Sagittarius B2(N) thus appears to be related to the unique physical conditions in the central molecular zone, manifested, for example, by the widespread presence of abundant H(3)(+). One intriguing theory for the high rotational temperature characterizing the population of the H(3)O(+) metastable levels may be formation pumping in molecular gas irradiated by X-rays emitted by the Galactic centre black hole. Alternatively, the pervasive presence of enhanced turbulence in the central molecular zone may give rise to shocks in the lower-density medium that is exposed to energetic radiation. PMID:23028163

  7. X-Ray Evidence for Multiphase Hot Gas with Solar Abundances in the Brightest Elliptical Galaxies

    CERN Document Server

    Buote, D A

    1998-01-01

    We examine whether single-phase models of the hot gas can successfully describe the ASCA and ROSAT spectra of NGC 1399, NGC 4472, NGC 4636, and NGC 5044. Broad-band spectral fitting of the ASCA SIS and GIS data accumulated within a radius of ~5 arcmin for each galaxy shows that single-phase models are unable to fit the SIS data near 1 keV. In addition, these single-phase models typically fail to produce the large equivalent widths of the K-alpha line blends of the H-like and He-like ions of Si and S which are measured independently of the Fe L emission lines. Two-phase models provide excellent broad-band fits to both the SIS and GIS data of each galaxy with the relative abundances (except for NGC 4636) fixed at their solar values. A simple multiphase cooling flow model fits nearly as well as the two-phase model for NGC 1399, NGC 4472, and NGC 5044. The multiphase models also predict more accurately the Si and S equivalent widths and the ratios of Si XIV/XIII and S XVI/XV than the single-phase models. Using va...

  8. Hot corrosion and its prevention in high temperature heavy oil firing gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Nakamori, M.; Kayano, I. [Mitsubishi Heavy Ind., Ltd., Hyogo (Japan). Res. and Dev. Center; Tsukuda, Y.; Takahashi, K.; Torigoe, T. [Takasago Machinery Works, Mitsubishi Heavy Industries, Ltd., Hyogo (Japan)

    1997-12-31

    Severe hot corrosion cases have been investigated for blades and vanes of heavy oil firing gas turbine applied with CoNiCrAlY coating and its preventive methods has been established through examination for corrosion contaminant sources as well as actual plant testing for new protective coatings. (1) The corrosion was a typical high temperature sulfidation caused by alkali sulfates and vanadium compounds such as Na{sub 2}SO{sub 4}, Na{sub 2}O-V{sub 2}O{sub 5}. (2) The source of alkali sulfates and vanadium compounds was impurities contained in fuel and combustion air, especially the combustion air had involved large quantities of alkaline metals in it. (3) The prevention method has been achieved by an installation of high efficiency air filter, control for impurities in fuel and application for new protective coatings such as CoCrAlYRe and CoCrAlY+Al (AlSi). (orig.) 8 refs.

  9. Synthesis of functional xLayMn/KIT-6 and features in hot coal gas desulphurization.

    Science.gov (United States)

    Xia, Hong; Zhang, Fengmei; Zhang, Zhaofei; Liu, Bingsi

    2015-08-28

    To enhance the stability of sorbents during continuous desulphurization-regeneration cycles, KIT-6 with 3D pore channels was used as a support for the sorbents. A series of mesoporous xLayMn/KIT-6 sorbents with different La/Mn atomic ratios were fabricated using a sol-gel method and their desulphurization properties of hot coal gas were investigated at 700-850 °C. 3La97Mn/KIT-6 performed the best at 800 °C with a breakthrough sulphur capacity of 11.56 g sulphur per 100 g sorbent. The eight successive desulphurization (800 °C)-regeneration (600 °C) cycles revealed that 3La97Mn/KIT-6 with endurable regeneration abilities could retain 80% of the initial sulphur capacity. It indicated a better desulphurization performance compared to pure 3La97Mn and 3La97Mn/MCM-41. The fresh and used xLayMn/KIT-6 sorbents were characterized by means of BET, XRD, HRTEM, XPS and H2-TPR techniques. The XRD patterns and HRTEM images of fresh and used 3La97Mn/KIT-6 verified that the utilization of KIT-6 effectively suppressed the aggregation of Mn2O3 particles and improved the stability of the sorbent.

  10. Development of a Calicum-Based Sorbent for Hot Gas Cleanup.

    Energy Technology Data Exchange (ETDEWEB)

    Wheelock, T.W.; Constant, K.; Doraiswamy, L.K.; Akiti, T.; Zhu, J.; Amanda, A.; Roe, R.

    1997-09-01

    Further review of the technical literature has provided additional information which will support the development of a superior calcium-based sorbent for hot gas cleanup in IGCC systems. Two general methods of sorbent preparation are being investigated. One method involves impregnating a porous refractory substrate with calcium while another method involves pelletizing lime or other calcium containing materials with a suitable binder. Several potential substrates, which are made of alumina and are commercially available, have been characterized by various methods. The surface area and apparent density of the materials have been measured, and it has been shown that some of the high surface area materials (i.e., 200-400 m{sub 2}/g) undergo a large decrease in surface area when heated to higher temperatures. Some of the lower surface area materials (i.e., 1-30 m{sub 2}/g) have been successfully impregnated with calcium by soaking them in a calcium nitrate solution and then heat treating them to decompose the nitrate. Potentially useful sorbents have also been prepared by pelletizing type I Portland cement and mixtures of cement and lime.

  11. The quest for hot gas in the halo of NGC 1511

    CERN Document Server

    Dahlem, M; Jansen, F; Heckman, T M; Weaver, K A; Strickland, D K

    2003-01-01

    XMM-Newton observations of the starburst galaxy NGC 1511 reveal the presence of a previously unknown extended hot gaseous phase of its ISM, which partly extends out of the disk plane. The emission distribution is asymmetric, being brightest in the eastern half of the galaxy, where also radio continuum observations suggest the highest level of star formation. Spectral analysis of the integral 0.2-12 keV X-ray emission from NGC 1511 indicates a complex emission composition. A model comprising a power law plus thermal plasma component, both absorbed by foreground gas, cannot explain all details of the observed spectrum, requiring a third spectral component to be added. This component can be a second thermal plasma, but other spectral models can be fitted as well. Its X-ray properties characterize NGC 1511 as a starburst galaxy. The X-ray-to-infrared luminosity ratio is consistent with this result. Together with the X-ray data, XMM-Newton obtained UV images of NGC 1511, tracing massive stars heating the ambient g...

  12. Synthesis of functional xLayMn/KIT-6 and features in hot coal gas desulphurization.

    Science.gov (United States)

    Xia, Hong; Zhang, Fengmei; Zhang, Zhaofei; Liu, Bingsi

    2015-08-28

    To enhance the stability of sorbents during continuous desulphurization-regeneration cycles, KIT-6 with 3D pore channels was used as a support for the sorbents. A series of mesoporous xLayMn/KIT-6 sorbents with different La/Mn atomic ratios were fabricated using a sol-gel method and their desulphurization properties of hot coal gas were investigated at 700-850 °C. 3La97Mn/KIT-6 performed the best at 800 °C with a breakthrough sulphur capacity of 11.56 g sulphur per 100 g sorbent. The eight successive desulphurization (800 °C)-regeneration (600 °C) cycles revealed that 3La97Mn/KIT-6 with endurable regeneration abilities could retain 80% of the initial sulphur capacity. It indicated a better desulphurization performance compared to pure 3La97Mn and 3La97Mn/MCM-41. The fresh and used xLayMn/KIT-6 sorbents were characterized by means of BET, XRD, HRTEM, XPS and H2-TPR techniques. The XRD patterns and HRTEM images of fresh and used 3La97Mn/KIT-6 verified that the utilization of KIT-6 effectively suppressed the aggregation of Mn2O3 particles and improved the stability of the sorbent. PMID:26204251

  13. Investigating the origin of hot gas lines in Herbig Ae/Be Stars

    CERN Document Server

    Cauley, P Wilson

    2016-01-01

    We analyze high-resolution UV spectra of a small sample of Herbig Ae/Be stars (HAEBES) in order to explore the origin of the $T\\sim10^5$ K gas in these stars. The C IV 1548,1550 \\AA\\ line luminosities are compared to non--simultaneous accretion rate estimates for the objects showing C IV emission. We show that the correlation between $L_{CIV}$ and $\\dot{M}$ previously established for classical T Tauri stars (CTTSs) seems to extend into the HAEBE mass regime, although the large spread in literature $\\dot{M}$ and $A_V$ values makes the actual relationship highly uncertain. With the exception of DX Cha, we find no evidence for hot, optically thick winds in our HAEBE sample. All other objects showing clear doublet emission in C IV can be well described by a two component (i.e., a single component for each doublet member) or four component (i.e., two components for each doublet member) Gaussian emission line fit. The morphologies and peak-flux velocities of these lines suggest they are formed in weak, optically th...

  14. Hot QCD, k-strings and the adjoint monopole gas model

    CERN Document Server

    Altes, C P K; Altes, Chris P. Korthals; Meyer, Harvey B.

    2005-01-01

    When the magnetic sector of hot QCD, 3D SU(N) Yang-Mills theory, is described as a dilute gas of non-Abelian monopoles in the adjoint representation of the magnetic group, Wilson loops of N-ality k are known to obey a periodic k(N-k) law. Lattice simulations have confirmed this prediction to a few percent for N=4 and 6. We describe in detail how the magnetic flux of the monopoles produces different area laws for spatial Wilson k-loops. A simple physical argument is presented, why the predicted and observed Casimir scaling is allowed in the large-N limit by usual power-counting arguments. The same scaling is also known to hold in two-loop perturbation theory for the spatial 't Hooft loop, which measures the electric flux. We then present new lattice data for 3D N=8 k-strings as long as 3`fm' that provide further confirmation. Finally we suggest new tests in theories with spontaneous breaking and in SO(4n+2) gauge groups.

  15. Hot-gas cleanup system model development. Volume II. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Ushimaru, K.; Bennett, A.; Bekowies, P.J.

    1982-11-01

    Under Contract to the Department of Energy (DOE) through the Morgantown Energy Technology Center (METC), Flow Industries, Inc., has developed computer models to simulate the physical performance of five hot-gas cleanup devices for pressurized, fluidized-bed combustion (PFBC), combined-cycle power plants. Separate cost models have also been developed to estimate the cost of each device. The work leading to the development of these models is described in Volume I of this report. This volume contains the user's manuals for both the physical and cost models. The manuals for the physical models are given first followed by those for the cost models. Each manual is a complete and separate document. The model names and devices and their respective subroutine names are: (1) Moving Granular Bed Filter by Combustion Power Company, USRCGB, QFCOST; (2) Ceramic Bag Filter by Acurex, USRACB, QDCOST; (3) Electrostatic Granular Bed Filter by General Electric, USRGGB, QACOST; (4) Electrostatic Precipitator by Research Cottrell, USRCEP, QECOST; and (5) Electrocyclone by General Electric, USRGCY, QBCOST.

  16. A regenerable sorbent injection/filtration process for H{sub 2}S removal from hot gas

    Energy Technology Data Exchange (ETDEWEB)

    Higgins, R.J.; Ji, W.; Connors, M.J.; Jones, J.F.; Goldsmith, R.L. [CeraMem Corp., Waltham, MA (United States)

    1996-12-31

    The operational characteristics of a hot gas desulfurization process involving regenerable sorbent injection and its subsequent collection with a ceramic filtration device were studied utilizing a bench-scale transport reactor. Hydrogen sulfide removal from simulated hot gas was evaluated as a function of both zinc oxide-based sorbent physical and chemical characteristics and various process parameters. In addition, the sorbent capture efficiency and regenerability of the ceramic filtration device were evaluated, and regeneration of sulfided sorbents via injection into an oxidizing gas was studied. For both sorbent sulfidation and spent sorbent regeneration, gas-solid reaction occurred both in the duct and within layers of partially reacted sorbent captured by the ceramic filter. Very high sulfur removal efficiencies were obtained only in highly reducing hot gas compositions at or above about 700 C, using stoichiometric ratio (defined as ZnO/H{sub 2}S ratio) values of about 1.5, and sorbent particles of about 20 {micro}m or less in diameter. Under such conditions, the experimental data indicated that reaction of H{sub 2}S with zinc vapor formed by reduction of zinc oxide contributed appreciably to sulfur removal. Negligible zinc loss from the hot zone of the reactor was detected, apparently due to rapid formation of zinc sulfide product layers on zinc oxide particles. The ceramic filtration devices captured 100% of all sorbent particles and were fully regenerable over periods of several tens of injection/backpulse cleaning cycles. Spent sorbent could be fully regenerated rapidly at 850 C without problems due to exotherm generation.

  17. X-ray Scaling Relation in Early-Type Galaxies: Dark Matter as a Primary Factor in Retaining Hot Gas

    CERN Document Server

    Kim, Dong-Woo

    2013-01-01

    We have revisited the X-ray scaling relations of early type galaxies (ETG) by investigating, for the first time, the LX,Gas - MTotal relation in a sample of 14 ETGs. In contrast to the large scatter (by a factor of 102-103) in the LX,Total - LB relation, we found a tight correlation between these physically motivated quantities with a rms deviation of a factor of 3 in LX,Gas = 1038 - 1043 erg s-1 or MTotal = a few x 1010 - a few x 1012 Mo. More striking, this relation becomes even tighter with a rms deviation of a factor of 1.3 among the gas-rich galaxies (with LX,Gas > 1040 erg s-1). In a simple power-law form, the new relation is (LX,Gas / 1040 erg s-1) = (MTotal / 3.2 x 1011 Mo)3. This relation is also consistent with the steep relation between the gas luminosity and temperature, LX,Gas ~ TGas4.5, identified by Boroson, Kim & Fabbiano (2011), if the gas is virialized. Our results indicate that the total mass of an ETG is the primary factor in regulating the amount of hot gas. Among the gas-poor galaxie...

  18. Catalytic hydrothermal gasification of biomass for the production of synthetic natural gas[Dissertation 17100

    Energy Technology Data Exchange (ETDEWEB)

    Waldner, M. H.

    2007-07-01

    Energy from biomass is a CO{sub 2} neutral, sustainable form of energy. Anaerobic digestion is an established technology for converting biomass to biogas, which contains around 60% methane, besides CO{sub 2} and various contaminants. Most types of biomass contain material that cannot be digested; in woody biomass, this portion is particularly high. Therefore, conventional anaerobic digestion is not suited for the production of biogas from woody biomass. While wood is already being converted to energy by conventional thermal methods (gasification with subsequent methanation), dung, manure, and sewage sludge represent types of biomass whose energy potential remains largely untapped (present energetic use of manure in Switzerland: 0.4%). Conventional gas phase processes suffer from a low efficiency due to the high water content of the feed (enthalpy of vaporization). An alternative technology is the hydrothermal gasification: the water contained within the biomass serves as reaction medium, which at high pressures of around 30 MPa turns into a supercritical fluid that exhibits apolar properties. Under these conditions, tar precursors, which cause significant problems in conventional gasification, can be solubilized and gasified. The need to dry the biomass prior to gasification is obsolete, and as a consequence high thermal process efficiencies (65 - 70%) are possible. Due to their low solubility in supercritical water, the inorganics that are present in the biomass (up to 20 wt % of the dry matter of manure) can be separated and further used as fertilizer. The biomass is thus not only converted into an energy carrier, but it allows valuable substances contained in the biomass to be extracted and re-used. Furthermore, the process can be used for aqueous waste stream destruction. The aim of this project at the Paul Scherrer Institute was to develop a catalytic process that demonstrates the gasification of wet biomass to synthetic natural gas (SNG) in a continuously

  19. Numerical and experimental study on shear coaxial injectors with hot hydrogen-rich gas/oxygen-rich gas and GH2/GO2

    Institute of Scientific and Technical Information of China (English)

    Jin Ping; Li Mao; Cai Guo-Biao

    2013-01-01

    The influences of the shear coaxial injector parameters on the combustion performance and the heat load of a combustor are studied numerically and experimentally.The injector parameters,including the ratio of the oxidizer pressure drop to the combustor pressure (Dp),the velocity ratio of fuel to oxidizer (Rv),the thickness (Wo),and the recess (Ho) of the oxidizer injector post tip,the temperature of the hydrogen-rich gas (TH) and the oxygen-rich gas (To),are integrated by the orthogonal experimental design method to investigate the performance of the shear coaxial injector.The gaseous hydrogen/oxygen at ambient temperature (GH2/GO2),and the hot hydrogen-rich gas/oxygen-rich gas are used here.The length of the combustion (Lc),the average temperatures of the combustor wall (Tw),and the faceplate (TF) are selected as the indicators.The tendencies of the influences of injector parameters on the combustion performance and the heat load of the combustor for the GH2/GO2 case are similar to those in the hot propellants case.However,the combustion performancein the hot propellant case is better than that in the GH2/GO2 case,and the heat load of the combustor is also larger than that in the latter case.

  20. CONSTRAINING THE MILKY WAY'S HOT GAS HALO WITH O VII AND O VIII EMISSION LINES

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Matthew J.; Bregman, Joel N., E-mail: mjmil@umich.edu, E-mail: jbregman@umich.edu [Department of Astronomy, University of Michigan, Ann Arbor, MI 48104 (United States)

    2015-02-10

    The Milky Way hosts a hot (≈2 × 10{sup 6} K), diffuse, gaseous halo based on detections of z = 0 O VII and O VIII absorption lines in quasar spectra and emission lines in blank-sky spectra. Here we improve constraints on the structure of the hot gas halo by fitting a radial model to a much larger sample of O VII and O VIII emission line measurements from XMM-Newton/EPIC-MOS spectra compared to previous studies (≈650 sightlines). We assume a modified β-model for the halo density distribution and a constant-density Local Bubble from which we calculate emission to compare with the observations. We find an acceptable fit to the O VIII emission line observations with χ{sub red}{sup 2} (dof) = 1.08 (644) for best-fit parameters of n{sub o}r{sub c}{sup 3β}=1.35±0.24 cm{sup –3} kpc{sup 3β} and β = 0.50 ± 0.03 for the hot gas halo and negligible Local Bubble contribution. The O VII observations yield an unacceptable χ{sub red}{sup 2} (dof) = 4.69 (645) for similar best-fit parameters, which is likely due to temperature or density variations in the Local Bubble. The O VIII fitting results imply hot gas masses of M(<50 kpc) = 3.8{sub −0.3}{sup +0.3}×10{sup 9} M{sub ⊙} and M(<250 kpc) = 4.3{sub −0.8}{sup +0.9}×10{sup 10} M{sub ⊙}, accounting for ≲50% of the Milky Way's missing baryons. We also explore our results in the context of optical depth effects in the halo gas, the halo gas cooling properties, temperature and entropy gradients in the halo gas, and the gas metallicity distribution. The combination of absorption and emission line analyses implies a sub-solar gas metallicity that decreases with radius, but that also must be ≥0.3 Z {sub ☉} to be consistent with the pulsar dispersion measure toward the Large Magellanic Cloud.

  1. On the Semimajor Axis Distribution of Extrasolar Gas Giant Planets: Why Hot Jupiters Are Rare Around High-Mass Stars

    OpenAIRE

    Currie, Thayne

    2009-01-01

    Based on a suite of Monte Carlo simulations, I show that a stellar-mass dependent lifetime of the gas disks from which planets form can explain the lack of hot Jupiters/close-in giant planets around high-mass stars and other key features of the observed semimajor axis distribution of radial velocity-detected giant planets. Using reasonable parameters for the Type II migration rate, regions of planet formation, and timescales for gas giant core formation, I construct synthetic distributions of...

  2. Pyrolysis Oil Stabilization: Hot-Gas Filtration; Cooperative Research and Development Final Report, CRADA Number CRD-09-333

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, R.

    2012-07-01

    The hypothesis that was tested in this task was that separation of char, with its associated mineral matter from pyrolysis vapors before condensation, will lead to improved oil quality and stability with respect to storage and transportation. The metric used to evaluate stability in this case was a 10-fold reduction in the rate of increase of viscosity as determined by ASTM D445 (the accelerated aging test). The primary unit operation that was investigated for this purpose was hot-gas filtration. A custom-built heated candle filter system was fabricated by the Pall Corporation and furnished to NREL for this test campaign. This system consisted of a candle filter element in a containment vessel surrounded by heating elements on the external surface of the vessel. The filter element and housing were interfaced to NREL?s existing 0.5 MTD pyrolysis Process Development Unit (PDU). For these tests the pyrolysis reactor of the PDU was operated in the entrained-flow mode. The HGF test stand was installed on a slipstream from the PDU so that both hot-gas filtered oil and bio-oil that was not hot-gas filtered could be collected for purposes of comparison. Two filter elements from Pall were tested: (1) porous stainless steel (PSS) sintered metal powder; (2) sintered ceramic powder. An extremely sophisticated bio-oil condensation and collection system was designed and fabricated at NREL and interfaced to the filter unit.

  3. The alignment and shape of dark matter, stellar, and hot gas distributions in the EAGLE and cosmo-OWLS simulations

    CERN Document Server

    Velliscig, Marco; Schaye, Joop; Bower, Richard G; Crain, Robert A; van Daalen, Marcel P; Vecchia, Claudio Dalla; Frenk, Carlos S; Furlong, Michelle; McCarthy, Ian G; Schaller, Matthieu; Theuns, Tom

    2015-01-01

    We report the alignment and shape of dark matter, stellar, and hot gas distributions in the EAGLE and cosmo-OWLS simulations. The combination of these state-of-the-art hydro-cosmological simulations enables us to span four orders of magnitude in halo mass ($11 < log_{10}(M_{200}/ [h^{-1}M_\\odot]) < 15$), a wide radial range ($-2.3 < log_{10}(r/[h^{-1}Mpc ]) < 1.3$) and redshifts $0 < z < 1$. The shape parameters of the dark matter, stellar and hot gas distributions follow qualitatively similar trends: they become more aspherical (and triaxial) with increasing halo mass, radius and redshift. We measure the misalignment of the baryonic components (hot gas and stars) of galaxies with their host halo as a function of halo mass, radius, redshift, and galaxy type (centrals vs satellites and early- vs late-type). Overall, galaxies align well with local distribution of the total (mostly dark) matter. However, the stellar distributions on galactic scales exhibit a median misalignment of about 45-50 d...

  4. Galaxy Formation with Local Photoionization Feedback -II. Effect of X-Ray Emission from Binaries and Hot Gas

    CERN Document Server

    Kannan, Rahul; Stinson, Greg S; Hennawi, Joe F; Marinacci, Federico; Springel, Volker; Maccio, Andrea V

    2015-01-01

    We study how X-rays from stellar binary systems and the hot intracluster medium (ICM) affect the radiative cooling rates of gas in galaxies. Our study uses a novel implementation of gas cooling in the moving-mesh hydrodynamics code \\textsc{arepo}. X-rays from stellar binaries do not affect cooling at all as their emission spectrum is too hard to effectively couple with galactic gas. In contrast, X-rays from the ICM couple well with gas in the temperature range $10^4 - 10^6$ K. Idealised simulations show that the hot halo radiation field has minimal impact on the dynamics of cooling flows in clusters because of the high virial temperature ($> 10^7$K), making the interaction between the gas and incident photons very ineffective. Satellite galaxies in cluster environments, on the other hand, experience a high radiation flux due to the emission from the host halo. Low mass satellites ($< 10^{12}\\rm{M_\\odot}$) in particular have virial temperatures that are exactly in the regime where the effect of the radiatio...

  5. Advanced technology catalytic combustor for high temperature ground power gas turbine applications

    Energy Technology Data Exchange (ETDEWEB)

    Etemad, S.; Karim, H.; Smith, L.L.; Pfefferle, W.C. [Precision Combustion, Inc., 25 Science Park Box 24, New Haven, CT 06511 (United States)

    1999-01-01

    We report results from a lean burn ultra-low emission catalytic combustor. In a sub-scale rig, atmospheric testing with methane demonstrated NO{sub x}<3, CO<5, and UHC<1ppm, with stable combustion at inlet temperatures of 400-500C (750-1020F) and combustor discharge temperatures of 1150-1540C (2100-2800F). Catalyst temperatures were held well below metal substrate material limits, while combustor discharge temperatures of up to 1540C (2800F) were achieved

  6. PENGARUH KATALIS Co DAN Fe TERHADAP KARAKTERISTIK CARBON NANOTUBES DARI GAS ASETILENA DENGAN MENGGUNAKAN PROSES CATALYTIC CHEMICAL VAPOUR DEPOSITION (CCVD

    Directory of Open Access Journals (Sweden)

    Tutuk Djoko Kusworo

    2013-11-01

    Full Text Available EFFECT OF Co AND Fe ON CARBON NANOTUBES CHARACTERISTICS FROM ACETYLENE USING CATALYTIC CHEMICAL VAPOUR DEPOSITION (CCVD PROCESS. Carbon Nanotubes (CNTs is one of the most well known nano-technology applications which the most of attracting the attention of researchers, because it has more advantages than other materials. The application of the CNT has extended into various aspects, such as electronics, materials, biology and chemistry. This research uses a system of Catalytic Chemical Vapour Deposition (CCVD, which aims to determine the influence of Co and Fe as a catalyst and zeolite 4A as a support catalyst with acetylene gas (C2H2 as carbon source in the synthesis of Carbon Nanotubes (CNTs. In this experiment, used the ratio of acetylene gas and flow rate of N2 gas is 1:1 by weight of the catalyst Co/Zeolite and Fe/Zeolite amounted to 0.5 grams at the operating temperature of 700oC for 20 minutes. N2 gas serves to minimize the occurrence of oxidation reaction (explosion when operating. From analysis result by Scanning Electron Microscopy (SEM shows the CNTs formed a type of MWNT with different of diameter size and product weight, depending on the size of the active component concentration on the catalyst. The larger of active components produced CNTs with larger diameter, whereas product weight syntheses result smaller. Use of the catalyst Fe/Zeolite produce CNTs with a diameter larger than the catalyst Co/Zeolite.  Carbon Nanotubes (CNTs merupakan salah satu aplikasi nanoteknologi yang paling terkenal dan banyak menarik perhatian para peneliti, karena memiliki beberapa kelebihan daripada material lainnya. Aplikasi dari CNT telah merambah ke berbagai aspek, seperti bidang elektronika, material, biologi dan kimia. Penelitian ini menggunakan sistem Catalytic Chemical Vapour Deposition (CCVD yang bertujuan untuk mengetahui pengaruh variasi Cobalt (Co dan Ferrum (Fe sebagai katalis dan zeolit tipe 4A sebagai penyangga katalis dengan gas

  7. Interactions Between Surface Reactions and Gas-phase Reactions in Catalytic Combustion and Their Influence on Ignition of HCCI Engine

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The catalytic combustion of methane in a microchannel whose surface was coated with platinum(Pt)catalyst was studied by numerical-simulation. The effects of gas-phase reactions on the whole catalytic combustion process were analyzed at a high inlet pressure. A sensitivity analysis of the detailed mechanisms of the surface reaction of methane on Pt revealed that the most sensitive reactions affecting the heterogeneous ignition are oxygen adsorption/desorption and methane adsorption, and the most sensitive reactions affecting the homogeneous ignition are OH and H2O adsorption/desorption. The combustion process of the homogeneous charge compression ignition(HCCI) engine whose piston face was coated with Pt catalyst was simulated. The effects of catalysis and the most sensitive reactions on the ignition timing and the concentration of the main intermediate species during the HCCI engine combustion are discussed. The results show that the ignition timing of the HCCI engine can be increased by catalysis, and the most sensitive reactions affecting the ignition timing of the HCCI engine are OH and H2O adsorption/desorption.

  8. Nine-Lump Kinetic Study of Catalytic Pyrolysis of Gas Oils Derived from Canadian Synthetic Crude Oil

    Directory of Open Access Journals (Sweden)

    Rui Zhang

    2016-01-01

    Full Text Available Catalytic pyrolysis of gas oils derived from Canadian synthetic crude oil on a kind of zeolite catalyst was conducted in a confined fluidized bed reactor for the production of light olefins. The overall reactants and products were classified into nine species, and a nine-lump kinetic model was proposed to describe the reactions based on appropriate assumptions. This kinetic model had 24 rate constants and a catalyst deactivation constant. The kinetic constants at 620°C, 640°C, 660°C, and 680°C were estimated by means of nonlinear least-square regression method. Preexponential factors and apparent activation energies were then calculated according to the Arrhenius equation. The apparent activation energies of the three feed lumps were lower than those of the intermediate product lumps. The nine-lump kinetic model showed good calculation precision and the calculated yields were close to the experimental ones.

  9. Effects of inert species in the gas phase in a model for the catalytic oxidation of CO

    CERN Document Server

    Buendia, G M

    2011-01-01

    We study by kinetic Monte Carlo simulations the catalytic oxidation of carbon monoxide on a surface in the presence of contaminants in the gas phase. The process is simulated by a Ziff-Gulari-Barshad (ZGB) model that has been modified to include the effect of the contaminants and to eliminate the unphysical oxygen-poisoned phase. The impurities can adsorb and desorb on the surface, but otherwise remain inert. We find that, if the impurities can not desorb, no matter how small their proportion in the gas mixture, the first order transition and the reactive window that characterize the ZGB model disappear. The coverages become continuous, and once the surface has reached a steady state there is no production of CO$_2$. This is quite different from the behavior of a system in which the surface presents a fixed percentage of impurities. When the contaminants are allowed to desorb, the reactive window appears again, and disappears at a value that depends on the proportion of contaminants in the gas and on their de...

  10. Change On The S-Z Effect Induced By The Cooling Flow CF On The Hot Electronic Gas At The Center OF The Clusters Of Galaxies

    OpenAIRE

    Enkelejd Caca

    2015-01-01

    ABSTRACT Building more accurate profiles for temperature and density of hot electronic gas concentrated in the center of clusters of galaxies is a constant problem in survey of Sunyeav Zeldovich effect SZ. An effect that consists in the inverse Compton effect of the hot electronic gas interacting with Cosmic Microwave Back- ground CMB photons passing through Intra Cluster Medium ICM. So far the Isothermal model is used for temperature profiling in the calculation of the inverse Compton effect...

  11. Volcanic controls on ash iron solubility: thermodynamic modeling of gas-ash interaction in the hot core of volcanic plumes

    Science.gov (United States)

    Hoshyaripour, G.; Hort, M.; Langmann, B.

    2012-04-01

    Recently it has been shown that volcanic ash can act as a fertilizer for phytoplankton bloom by injecting bio-available iron into the surface ocean. However, it is also well known that iron in volcanic ash at least at its generation point (i.e. magma) is mostly in insoluble form, i.e. not bio-available. Although different volcanic and atmospheric processes are assumed to contribute to the transformation of insoluble iron into soluble salts, the causes of iron mobilization in volcanic ash are poorly constrained. Here we explore the volcanic control on the mobilization of iron in volcanic ash in the hot core of volcanic plumes (T>600° C) based on thermodynamic equilibrium considerations. A conceptual box model is considered for the hot core in which 1000° C magmatic gas, ash and 25° C ambient air are mixed. The initial composition of volcanic gas and ash are parameterized based on three types of tectonic settings (convergent plate, divergent plate, and hot spot) and basaltic to rhyolitic magmas. The effect of the initial oxidation state is also considered by changing the oxygen fugacity. First, magmatic oxides (i.e. SiO2, FeO, MgO etc) are titrated into the magmatic gas at constant temperature and fugacity in order to generate the initial iron carrying minerals. Since the alteration of ash composition is mainly diffusion controlled, we assume that inside the hot core of the volcanic plume the Fe speciation is only affected at or near to the ash surface. Results show that the main initial iron carrying minerals are usually ilmenite and fayalite with some addition of pyhrrotite at reduced conditions in divergent plate and hot spot settings. Then the 1000° C magmatic gas-ash mixture is mixed with the 25° C air (N2 79%, O2 21%) until a temperature of 600° C is reached. Results demonstrate that the hot core functions as an oxidizing reactor for the ash surface transforming the whole Fe2+ minerals to Fe3+ species while being cooled to 600° C. However, in reduced

  12. On the Semimajor Axis Distribution of Extrasolar Gas Giant Planets: Why Hot Jupiters Are Rare Around High-Mass Stars

    CERN Document Server

    Currie, Thayne

    2009-01-01

    Based on a suite of Monte Carlo simulations, I show that a stellar-mass dependent lifetime of the gas disks from which planets form can explain the lack of hot Jupiters/close-in giant planets around high-mass stars and other key features of the observed semimajor axis distribution of radial velocity-detected giant planets. Using reasonable parameters for the Type II migration rate, regions of planet formation, and timescales for gas giant core formation, I construct synthetic distributions of jovian planets. A planet formation/migration model assuming a stellar mass-dependent gas disk lifetime reproduces key features in the observed distribution by preferentially stranding planets around high-mass stars at large semimajor axes.

  13. Structural and catalytic properties of a novel vanadium containing solid core mesoporous silica shell catalysts for gas phase oxidation reaction

    Indian Academy of Sciences (India)

    N Venkatathri; Vijayamohanan K Pillai; A Rajini; M Nooka Raju; I A K Reddy

    2013-01-01

    A novel vanadium containing solid core mesoporous silica shell catalyst was synthesized with different Si/V ratios by sol-gel method under neutral conditions. The synthesized materials were characterized by various techniques and gas phase diphenyl methane oxidation reaction. The mesoporosity combined with microporosity are formed by incorporation of octadecyltrichloro silane and triethylamine in the catalyst and it was found out from E-DAX and BET—surface area analysis. The material was found to be nanocrystalline. Vanadium is present as V4+ species in as-synthesized samples and convert to V5+ on calcination. Most of the vanadium is present in tetrahedral or square pyramidal environment. Incorporation of vanadium in silica framework was confirmed by 29Si MAS NMR analysis. Among the various vanadium containing solid core mesoporous silica shell catalysts, the Si/V =100 ratio exhibited maximum efficiency towards diphenyl methane to benzophenone gas phase reaction. The optimum condition required for maximum conversion and selectivity was found out from the catalytic studies.

  14. Effects of Natural Convection and Radiation inside Hot-Gas-Duct on Temperature Distribution on the Surface

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Injun; Hong, Sungyull; Bai, Cheolho; Shim, Jaesool [Yeungnam Univ., Kyungsan (Korea, Republic of); Hong, Sungdeok; Kim, Chansoo; Kim, Minhwan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    The VHTR necessarily requires an intermediate loop composed of a hot gas duct(HGD), an intermediate heat exchanger (IHX) and a process heat exchanger. The IHX is one of the important components of VHTR system because the IHX transfers the 950 .deg. high temperature massive heat to a hydrogen production plant or power conversion unit at high system pressure. Hot gas duct (HGD) is a unique component of a gas cooled reactor (GCR). The internal of a HGD is insulated using a ceramic fiber insulator (Kaowool) to prevent a mechanical failure itself from high temperature and high pressure operating conditions. The coolant temperature at the internal of a HGD can go up to 950 .deg. C. Thermo-hydraulic simulation using the COMSOL commercial solver is successfully performed at a uniform heat flux condition in a horizontal HGD. We obtained nonlinear temperature distribution from the COMSOL simulation with the assumption of the insulator in a HGD governed with conduction and convection heat transfer in porous medium.

  15. Performance and economic evaluation of the seahorse natural gas hot water heater conversion at Fort Stewart. Interim report, 1994 Summer

    Energy Technology Data Exchange (ETDEWEB)

    Winiarski, D.W.

    1995-01-01

    The federal government is the largest single energy consumer in the United States cost valued at nearly $10 billion annually. The US Department of Energy`s (DOE) Federal Energy Management Program (FEMP) supports efforts to reduce energy use and associated expenses in the federal sector. One such effort, the New Technology Demonstration Program (NTDP), seeks to evaluate new energy-saving US technologies and secure their more timely adoption by the US government. Pacific Northwest Laboratory (PNL) is one of four DOE laboratories that participate in the New Technologies Demonstration Program, providing technical expertise and equipment to evaluate new, energy-saving technologies being studied under that program. This interim report provides the results of a field evaluation that PNL conducted for DOE/FEMP and the US Department of Defense (DoD) Strategic Environmental Research and Development Program (SERDP) to examine the performance of a candidate energy-saving technology-a hot water heater conversion system to convert electrically heated hot water tanks to natural gas fuel. The unit was installed at a single residence at Fort Stewart, a US Army base in Georgia, and the performance was monitored under the NTDP. Participating in this effort under a Cooperative Research and Development Agreement (CRADA) were Gas Fired Products, developers of the technology; the Public Service Company of North Carolina; Atlanta Gas Light Company; the Army Corps of Engineers; Fort Stewart; and Pacific Northwest Laboratory.

  16. Early hot electrons generation and beaming in ICF gas filled hohlraums at the National Ignition Facility

    Science.gov (United States)

    Dewald, Eduard; Michel, Pierre; Hartemann, Fred; Milovich, Jose; Hohenberger, Matthias; Divol, Laurent; Landen, Otto; Pak, Arthur; Thomas, Cliff; Doeppner, Tilo; Bachmann, Benjamin; Meezan, Nathan; MacKinnon, Andrew; Hurricane, Omar; Callahan, Debbie; Hinkel, Denise; Edwards, John

    2015-11-01

    In laser driven hohlraum capsule implosions on the National Ignition Facility, supra-thermal hot electrons generated by laser plasma instabilities can preheat the capsule. Time resolved hot electron Bremsstrahlung spectra combined with 30 keV x-ray imaging uncover for the first time the directionality of hot electrons onto a high-Z surrogate capsule located at the hohlraum center. In the most extreme case, we observed a collimated beaming of hot electrons onto the capsule poles, reaching 50x higher localized energy deposition than for isotropic electrons. A collective SRS model where all laser beams in a cone drive a common plasma wave provides a physical interpretation for the observed beaming. Imaging data are used to distinguish between this mechanism and 2ωp instability. The amount of hot electrons generated can be controlled by the laser pulse shape and hohlraum plasma conditions. This work performed under the auspices of the U.S. DOE by LLNL under Contract DE-AC52-07NA27344.

  17. Catalytic reduction of methane/unburned hydrocarbons in smoke from lean-burn gas engines

    International Nuclear Information System (INIS)

    The aim of this project has been: To describe the flue gas conditions of typical stationary gas engines for cogeneration; To evaluate the predominant causes of deactivation of oxidation catalysts under realistic operation conditions; To develop improved long-term stable oxidation catalysts; To evaluate alternative catalyst-based methane reduction technologies. Most gas engines for stationary purposes are efficient lean-burn gas engines. Both the high efficiency and the very lean operation lead to low exhaust temperatures. However, there is now a tendency to design engines with un-cooled exhaust manifolds. This leads to higher shaft efficiency and increases the exhaust temperature. Exhaust gas composition and temperatures during continuous operation and start/stops are given in this report. Analyses have been made of catalyst samples to find predominant causes for oxidation catalyst deactivation. The analyses have shown that the presence of sulphur dioxide in the flue gas causes sulphur poisoning on the active catalyst surface. This effect is dependent on both the catalyst formulation and the catalyst support material composition. Neither sintering, nor other poisoning components than sulphur have been on the examined catalyst samples. The sulphur dioxide in the exhaust is a result of the sulphur in the odorisation additive used in the natural gas (approx. 10 mg/n3 m THT) and of the sulphur present in combusted lubrication oil. These sources leads to a level of approx. 0.3 - 0.6 ppm (vol) SO2 in the exhaust gas. Based on a large number of laboratory tests, a new oxidation catalyst formulation has been developed and successfully tested over 5000 hours of operation at a commercial cogeneration plant. This long-term testing has been additionally supplemented by short-term testings at test sites to see performance under other operation conditions. It has been shown that a rise in flue gas temperature (from e.g. 450 deg. C) will significantly reduce the necessary

  18. Coupled simulation of CFD-flight-mechanics with a two-species-gas-model for the hot rocket staging

    Science.gov (United States)

    Li, Yi; Reimann, Bodo; Eggers, Thino

    2016-11-01

    The hot rocket staging is to separate the lowest stage by directly ignite the continuing-stage-motor. During the hot staging, the rocket stages move in a harsh dynamic environment. In this work, the hot staging dynamics of a multistage rocket is studied using the coupled simulation of Computational Fluid Dynamics and Flight Mechanics. Plume modeling is crucial for a coupled simulation with high fidelity. A 2-species-gas model is proposed to simulate the flow system of the rocket during the staging: the free-stream is modeled as "cold air" and the exhausted plume from the continuing-stage-motor is modeled with an equivalent calorically-perfect-gas that approximates the properties of the plume at the nozzle exit. This gas model can well comprise between the computation accuracy and efficiency. In the coupled simulations, the Navier-Stokes equations are time-accurately solved in moving system, with which the Flight Mechanics equations can be fully coupled. The Chimera mesh technique is utilized to deal with the relative motions of the separated stages. A few representative staging cases with different initial flight conditions of the rocket are studied with the coupled simulation. The torque led by the plume-induced-flow-separation at the aft-wall of the continuing-stage is captured during the staging, which can assist the design of the controller of the rocket. With the increasing of the initial angle-of-attack of the rocket, the staging quality becomes evidently poorer, but the separated stages are generally stable when the initial angle-of-attack of the rocket is small.

  19. The alignment and shape of dark matter, stellar, and hot gas distributions in the EAGLE and cosmo-OWLS simulations

    Science.gov (United States)

    Velliscig, Marco; Cacciato, Marcello; Schaye, Joop; Crain, Robert A.; Bower, Richard G.; van Daalen, Marcel P.; Dalla Vecchia, Claudio; Frenk, Carlos S.; Furlong, Michelle; McCarthy, I. G.; Schaller, Matthieu; Theuns, Tom

    2015-10-01

    We report the alignment and shape of dark matter, stellar, and hot gas distributions in the EAGLE (Evolution and Assembly of GaLaxies and their Environments) and cosmo-OWLS (OverWhelmingly Large Simulations) simulations. The combination of these state-of-the-art hydrodynamical cosmological simulations enables us to span four orders of magnitude in halo mass (11 ≤ log10(M200/[ h-1 M⊙]) ≤ 15), a wide radial range (-2.3 ≤ log10(r/[ h-1 Mpc]) ≤ 1.3) and redshifts 0 ≤ z ≤ 1. The shape parameters of the dark matter, stellar and hot gas distributions follow qualitatively similar trends: they become more aspherical (and triaxial) with increasing halo mass, radius, and redshift. We measure the misalignment of the baryonic components (hot gas and stars) of galaxies with their host halo as a function of halo mass, radius, redshift, and galaxy type (centrals versus satellites and early- versus late-type). Overall, galaxies align well with the local distribution of the total (mostly dark) matter. However, the stellar distributions on galactic scales exhibit a median misalignment of about 45-50 deg with respect to their host haloes. This misalignment is reduced to 25-30 deg in the most massive haloes (13 ≤ log10(M200/[ h-1 M⊙]) ≤ 15). Half of the disc galaxies in the EAGLE simulations have a misalignment angle with respect to their host haloes larger than 40 deg. We present fitting functions and tabulated values for the probability distribution of galaxy-halo misalignment to enable a straightforward inclusion of our results into models of galaxy formations based on purely collisionless N-body simulations.

  20. Catalytic conversion of biomass-derived synthesis gas to liquid fuels

    OpenAIRE

    Suárez París, Rodrigo

    2016-01-01

    Climate change is one of the biggest global threats of the 21st century. Fossil fuels constitute by far the most important energy source for transportation and the different governments are starting to take action to promote the use of cleaner fuels. Biomass-derived fuels are a promising alternative for diversifying fuel sources, reducing fossil fuel dependency and abating greenhouse gas emissions. The research interest has quickly shifted from first-generation biofuels, obtained from food co...

  1. On the contribution of plasminos to the shear viscosity of a hot and dense Yukawa-Fermi gas

    CERN Document Server

    Sadooghi, N

    2015-01-01

    Using the standard Green-Kubo formalism, we determine the shear viscosity $\\eta$ of a hot and dense Yukawa-Fermi gas. In particular, we study the effect of particle and plasmino excitations on thermal properties of the fermionic part of the shear viscosity, and explore the effects of thermal corrections to particle masses on bosonic and fermionic shear viscosities, $\\eta_b$ and $\\eta_f$. It turns out that the effects of plasminos on $\\eta_f$ become negligible with increasing (decreasing) temperature (chemical potential).

  2. Control element for controlling a hot gas piston engine, and a hot gas engine with such a control element. Regelelement zur Regelung einer Heissgaskolbenmaschine sowie ein Heissgasmotor mit einem derartigen Regelelement

    Energy Technology Data Exchange (ETDEWEB)

    Jaspers, H.A.

    1981-09-10

    The invention refers to a control element for controlling a hot gas piston engine, which contains a movable part, which takes up a certain position depending on the engine speed and with one or more adjustable valves for removing or introducing the working medium from or into the working part of the engine. The purpose of the invention is to create a robust and cheap control element, which emits a signal proportional to speed, by which the engine can be controlled and which is not mechanically connected to the crankshaft. According to the invention, the problem is solved by the part consisting of a movable wall, which separates 2 closed spaces, which are connected together by a capillary tube and where the first space on one side of the movable wall is connected to the working space of the hot gas piston engine by a first non-return valve allowing flow in the direction of the first space, and the second space on the other side of this wall is connected to the same working space by a second non-return valve preventing flow in the direction of the second space, where the gaseous working medium is in the working space and where cyclic pressure changes occur, and where further there is a spring loaded element, which exerts forces on the movable wall in the direction of the first space.

  3. Operating condition influences on PCDD/Fs emissions from sinter pot tests with hot flue gas recycling

    Institute of Scientific and Technical Information of China (English)

    Yongmei Yu; Minghui Zheng; Xianwei Li; Xiaolei He

    2012-01-01

    This study was designed to clarify the influence of operating conditions on the formation and emissions of polychlorinated-p- dibenzodioxins and dibenzofurans (PCDD/Fs) from a sintering process with hot flue gas recycling.A pilot scale sinter pot with simulated flue gas recycling was developed,and four key operational parameters,including temperature,oxygen content of the simulated waste,flue gas,the coke rate of the sintering mixture,and the quicklime quality,were selected for exploring PCDD/Fs formation.The results showed that the temperature of the recycled flue gas had a major affect on PCDD/Fs formation,and a high temperature could significantly increase their formation during sintering.A clear linear correlation between the temperature of recycling flue gas and PCDD/Fs emission (r =0.93) was found.PCDD/Fs could be reduced to a certain extent by decreasing the level of oxygen in the recycled flue gas,while sintering quality was unchanged.The coke rate had no significant influence on the formation of PCDD/Fs,but the quality of quicklime used in the sintering mixture could affect not only the amount of PCDD/Fs emissions but also the sintering productivity.Compared with a benchmark sinter pot test,PCDD/Fs emissions markedly decreased with improvements to quicklime quality.However,the reduction in PCDD/Fs emissions realized by using high-quality quicklime was limited by the temperature of the inlet gas.The highest reduction achieved was 51% compared with conventional quicklime when the temperature of the inlet gas was 150 ℃.

  4. Hot Corrosion of Inconel 625 Overlay Weld Cladding in Smelting Off-Gas Environment

    Science.gov (United States)

    Mohammadi Zahrani, E.; Alfantazi, A. M.

    2013-10-01

    Degradation mechanisms and hot corrosion behavior of weld overlay alloy 625 were studied. Phase structure, morphology, thermal behavior, and chemical composition of deposited salt mixture on the weld overlay were characterized utilizing XRD, SEM/EDX, DTA, and ICP/OES, respectively. Dilution level of Fe in the weldment, dendritic structure, and degradation mechanisms of the weld were investigated. A molten phase formed on the weld layer at the operating temperature range of the boiler, which led to the hot corrosion attack in the water wall and the ultimate failure. Open circuit potential and weight-loss measurements and potentiodynamic polarization were carried out to study the hot corrosion behavior of the weld in the simulated molten salt medium at 873 K, 973 K, and 1073 K (600 °C, 700 °C, and 800 °C). Internal oxidation and sulfidation plus pitting corrosion were identified as the main hot corrosion mechanisms in the weld and boiler tubes. The presence of a significant amount of Fe made the dendritic structure of the weld susceptible to preferential corrosion. Preferentially corroded (Mo, Nb)-depleted dendrite cores acted as potential sites for crack initiation from the surface layer. The penetration of the molten phase into the cracks accelerated the cracks' propagation mainly through the dendrite cores and further crack branching/widening.

  5. Catalytic oxidation of gas-phase elemental mercury by nano-Fe2O3

    Institute of Scientific and Technical Information of China (English)

    Fanhai Kong; Jianrong Qiu; Hao Liu; Ran Zhao; Zhihui Ai

    2011-01-01

    Heterogeneous oxidation of gas-phase Hg0 by nano-Fe2O3 was investigated on a fixed bed reactor, and the effects of oxygen concentration, bed temperature, water vapour concentration and particle size have been discussed. The results showed that Hg0 could be oxidized by active oxygen atom on the surface of nano-Fe2O3 as well as lattice oxygen in nano-Fe2O3. Among the factors that affect Hg0 oxidation by nano-Fe2O3, bed temperature plays an important role. More than 40% of total mercury was oxidized at 300℃,however, the test temperature at 400℃ could cause sintering of nano-catalyst, which led to a lower efficiency of Hg0 oxidation. The increase of oxygen concentration could promote mercury oxidation and led to higher Hg0 oxidation efficiency. No obvious mercury oxidation was detected in the pure N2 atmosphere, which indicates that oxygen is required in the gas stream for mercury oxidation. The presence of water vapour showed different effects on mercury oxidation depending on its concentration. The lower content of water vapour could promote mercury oxidation, while the higher content of water vapour inhibits mercury oxidation.

  6. Catalytic Steam Reforming of Bio-Oil to Hydrogen Rich Gas

    DEFF Research Database (Denmark)

    Trane-Restrup, Rasmus

    Bio-oil is a liquid produced by pyrolysis of biomass and its main advantage compared with biomass is an up to ten times higher energy density. This entails lower transportation costs associated with the utilization of biomass for production of energy and fuels. Nevertheless, the bio-oil has a low...... heating value and high content of oxygen, which makes it unsuited for direct utilization in engines. One prospective technology for upgrading of bio-oil is steam reforming (SR), which can be used to produce H2 for upgrading of bio-oil through hydrodeoxygenation or synthesis gas for processes like...... with both Ni/Ce0.6Zr0.4O2 and Ni/MgAl2O4. The carbon deposition over Ni/Ce0.6Zr0.4O2 and Ni/MgAl2O4 had a maximum at 500 ‰, which coincided with the maximum in the ethene formation. This, along with estimations of the anity for carbon deposition from the gas composition, showed that ethene is the main...

  7. Testing Sunyaev-Zel'dovich measurements of the hot gas content of dark matter haloes using synthetic skies

    CERN Document Server

    Brun, Amandine M C Le; Melin, Jean-Baptiste

    2015-01-01

    [Abridged] A large fraction of the baryons in the Universe are `missing' and believed to reside in the form of warm-hot gas in and around the dark matter haloes of massive galaxies and galaxy groups and clusters. The thermal Sunyaev-Zel'dovich (tSZ) effect offers a means of probing this component directly. The Planck collaboration recently performed a tSZ stacking analysis of a large sample of `locally brightest galaxies' (LBGs) selected from the Sloan Digital Sky Survey DR7 and, surprisingly, inferred an approximately self-similar relation between the tSZ flux and halo mass from massive clusters down to individual galaxies. At face value, this implies that galaxies, groups and clusters have the same hot gas mass fractions, a result which is in apparent conflict with X-ray observations. Here, we test the robustness of the inferred trend using synthetic maps of the tSZ effect sky generated from cosmological hydrodynamical simulations. We analyse these maps using the same tools and assumptions applied in the Pl...

  8. The Megasecond Chandra XVP Observation of NGC 3115: Witnessing the Flow of Hot Gas within the Bondi Radius

    CERN Document Server

    Wong, Ka-Wah; Shcherbakov, Roman V; Yukita, Mihoko; Million, Evan T; Bregman, Joel N

    2013-01-01

    Observational confirmation of hot accretion model predictions has been hindered by the challenge to resolve spatially the Bondi radii of black holes with X-ray telescopes. Here, we use the Megasecond Chandra X-ray Visionary Project (XVP) observation of the NGC~3115 supermassive black hole to place the first direct observational constraints on the spatially and spectroscopically resolved structures of the X-ray emitting gas inside the Bondi radius of a black hole. We measured temperature and density profiles of the hot gas from a fraction out to tens of the Bondi radius (R_B = 2.4-4.8 arcsec = 112-224 pc). The projected temperature jumps significantly from ~0.3 keV beyond 5 arcsec to ~0.7 keV within ~4-5 arcsec, but then abruptly drops back to ~0.3 keV within ~3 arcsec. This is contrary to the expectation that the temperature should rise toward the center for a radiatively inefficient accretion flow. A hotter thermal component of ~1 keV inside 3 arcsec (~150 pc) is revealed using a two component thermal model,...

  9. Selectivity of Catalytically Modified Tin Dioxide to CO and NH3 Gas Mixtures

    Directory of Open Access Journals (Sweden)

    Artem Marikutsa

    2015-10-01

    Full Text Available This paper is aimed at selectivity investigation of gas sensors, based on chemically modified nanocrystalline tin dioxide in the detection of CO and ammonia mixtures in air. Sol-gel prepared tin dioxide was modified by palladium and ruthenium oxides clusters via an impregnation technique. Sensing behavior to CO, NH3 and their mixtures in air was studied by in situ resistance measurements. Using the appropriate match of operating temperatures, it was shown that the reducing gases mixed in a ppm-level with air could be discriminated by the noble metal oxide-modified SnO2. Introducing palladium oxide provided high CO-sensitivity at 25–50 °C. Tin dioxide modified by ruthenium oxide demonstrated increased sensor signals to ammonia at 150–200 °C, and selectivity to NH3 in presence of higher CO concentrations.

  10. Impregnation of Catalytic Metals in Single-Walled Carbon Nanotubes for Toxic Gas Conversion in Life Support System

    Science.gov (United States)

    Li, Jing; Wignarajah, Kanapathipillai; Cinke, Marty; Partridge, Harry; Fisher, John

    2004-01-01

    Carbon nanotubes (CNTs) possess extraordinary properties such as high surface area, ordered chemical structure that allows functionalization, larger pore volume, and very narrow pore size distribution that have attracted considerable research attention from around the world since their discovery in 1991. The development and characterization of an original and innovative approach for the control and elimination of gaseous toxins using single walled carbon nanotubes (SWNTs) promise superior performance over conventional approaches due to the ability to direct the selective uptake of gaseous species based on their controlled pore size, increased adsorptive capacity due to their increased surface area and the effectiveness of carbon nanotubes as catalyst supports for gaseous conversion. We present our recent investigation of using SWNTs as catalytic supporting materials to impregnate metals, such as rhodium (Rh), palladium (Pd) and other catalysts. A protocol has been developed to oxidize the SWNTs first and then impregnate the Rh in aqueous rhodium chloride solution, according to unique surface properties of SWNTs. The Rh has been successfully impregnated in SWNTs. The Rh-SWNTs have been characterized by various techniques, such as TGA, XPS, TEM, and FTIR. The project is funded by a NASA Research Announcement Grant to find applications of single walled nanocarbons in eliminating toxic gas Contaminant in life support system. This knowledge will be utilized in the development of a prototype SWNT KO, gas purification system that would represent a significant step in the development of high efficiency systems capable of selectively removing specific gaseous for use in regenerative life support system for human exploration missions.

  11. Characterization of the efficiency of the gas-solid contact in circulating bed at by the use of a test reaction: the cumene catalytic cracking

    Energy Technology Data Exchange (ETDEWEB)

    Bayle, J.; Gauthier, T.; Pontier, R. [Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France); Briens, C.L.; Bergougnou, M. [University of Western Ontario, London, ON (Canada). Dept. of Physics

    1995-12-31

    The gas-solid down with the stream reactor, the ``downer``, presents a main interest for the high-speed reactions because it is well adapted to hard conditions uses: very short residence times, high temperatures and feeds of catalyst. This reactor type already presents a certain advantage to estimate the charges or new catalysts potential. But, it particularly constitutes an interesting option for some processes as petroleum cuts catalytic cracking. In order to intensify the contact between the catalyst and the reagents, the temperature increase of the reagents has to be almost instantaneous and the initial contact between the gas and the solid particles particularly effective. So as to validate these two hypothesis, the test reaction of the cumene catalytic cracking is carried out in the pilot unit ``downer`` of the Western Ontario University. (O.M.). 11 refs., 3 figs.

  12. Amine-based post-combustion CO2 capture in air-blown IGCC systems with cold and hot gas clean-up

    International Nuclear Information System (INIS)

    Highlights: • Hot fuel gas clean-up is a very favorable technology for IGCC concepts. • IGCC net efficiency reduces to 41.5% when realizing post-combustion CO2 capture. • Complex IGCC layouts are necessary if exhaust gas recirculation is realized. • IGCC performance does not significantly vary with exhaust gas recirculation. - Abstract: This paper focuses on the thermodynamic performance of air-blown IGCC systems with post-combustion CO2 capture by chemical absorption. Two IGCC technologies are investigated in order to evaluate two different strategies of coal-derived gas clean-up. After outlining the layouts of two power plants, the first with conventional cold gas clean-up and the second with hot gas clean-up, attention is paid to the CO2 capture station and to issues related to exhaust gas recirculation in combined cycles. The results highlight that significant improvements in IGCC performance are possible if hot coal-derived gas clean-up is realized before the syngas fuels the combustion turbine, so the energy cost of CO2 removal in an amine-based post-combustion mode is less strong. In particular, IGCC net efficiency as high as 41.5% is calculated, showing an interesting potential if compared to the one of IGCC systems with pre-combustion CO2 capture. Thermodynamic effects of exhaust gas recirculation are investigated as well, even though IGCC performance does not significantly vary against a more complicated plant layout

  13. The Energy Efficiency of Hot Water Production by Gas Water Heaters with a Combustion Chamber Sealed with Respect to the Room

    OpenAIRE

    Grzegorz Czerski; Andrzej Strugała

    2014-01-01

    This paper presents investigative results of the energy efficiency of hot water production for sanitary uses by means of gas-fired water heaters with the combustion chamber sealed with respect to the room in single-family houses and multi-story buildings. Additionally, calculations were made of the influence of pre-heating the air for combustion in the chimney and air supply system on the energy efficiency of hot water production. CFD (Computational Fluid Dynamics) software was used for calcu...

  14. The Cosmic Evolution of Galaxies: The Hunt for Hot Gas (and Winds!) at High Redshift

    Science.gov (United States)

    Hornschemeier, Ann; Kilbourne, Caroline; Lehmer, Bret; Yukita, Mihoko; Smith, Randall; Basu-Zych, Antara; Ptak, Andrew; Tatum, Malachi

    Deep surveys with current missions have revealed a population of high-redshift normal galaxies whose X-ray emission is dominated not by accretion onto supermassive black holes, but by the hot interstellar medium and accreting neutron star and black hole binary populations. Enormous progress has been made on the evolution of galaxies in the X-ray band, however there are some glaring holes in our understanding. For one, it is very difficult to measure the properties of the hot phase of the interstellar medium at high redshift, which in many galaxies is tremendously important component. Also, we know from optical, IR and UV studies that outflows from starburst galaxies appear to be relatively ubiquitous; such outflows are thought to be superwinds from the combination of many supernova explosions and stellar winds. Only with high-resolution X-ray spectroscopy will we have the capability of catching the hot phase of these outflows. The outflows remove fuel for subsequent generations of star formation and pollute the Intergalactic Medium with metals. Prospects for observations by next-generation X-ray spectroscopic instruments will be discussed.

  15. Support effects and catalytic trends for water gas shift activity of transition metals

    DEFF Research Database (Denmark)

    Boisen, Astrid; Janssens, T.V.W.; Schumacher, Nana Maria Pii;

    2010-01-01

    CO and atomic oxygen on the metal; the latter is a good measure for the reactivity of the metal towards H2O. Generally, the activity of the catalysts with the Ce0.75Zr0.25O2 support is higher, compared to the corresponding MgAl2O4-supported catalysts. Exceptions are Cu and Au, which have a higher......Water gas shift activity measurements for 12 transition metals (Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Re, Ir, Pt, Au) supported on inert MgAl2O4 and Ce0.75Zr0.25O2 are presented, to elucidate the influence of the active metal and the support. The activity is related to the adsorption energy of molecular...... activity on the MgAl2O4 support and are both characterized by weak CO adsorption. For the MgAl2O4-supported catalysts a volcano-type relation between the activity and the adsorption energy of atomic oxygen on the metal is obtained. The maximum activity is found for metals with a binding energy of oxygen...

  16. Catalytic performance of cerium iron complex oxides for partial oxidation of methane to synthesis gas

    Institute of Scientific and Technical Information of China (English)

    LI Kongzhai; WANG Hua; WEI Yonggang; LIU Mingchun

    2008-01-01

    The cerium iron complex oxides oxygen carder was prepared by the co-precipitation method. The reactions between methane and lattice oxygen from the complex oxides were investigated in a fixed micro-reactor system. The reduced oxygen carrier could be re-oxidized by air and its initial state could be restored. The characterizations of the oxygen carriers were studied using XRD, O2-TPD, and H2-TPR. The results showed that the bulk lattice oxygen of CeO2-Fe2O3 was found to be suitable for the partial oxidation of methane to synthesis gas. There were two kinds of oxygen species on the oxygen carder: the stronger oxygen species that was responsible for the complete oxidation of methane, and the weaker oxygen species (bulk lattice oxygen) that was responsible for the selective oxidation of methane to CO and H2 at a higher temperature. Then, the lost bulk lattice oxygen could be selectively supplemented by air re-oxidation at an appropriate reaction con-dition. CeFeO3 appeared on the oxygen carrier after 10 successive redox cycles, however, it was not bad for the selectivity of CO and H2.

  17. Gas isotopes and geochemistry of hot springs in Hengjing,Jiangxi Province

    Institute of Scientific and Technical Information of China (English)

    周文斌; 张卫民

    2001-01-01

    With emphasis on gas isotopes and geochemistry as well as hydrogeochemistry, a field investigation has been carried out in Hengjing geothermal area, south Jiangxi Province of south-eastern China. The water chemistry of the geothermal waters indicates their local meteoric water origin, whereas their gas composition and carbon and helium isotopes reveal that some gases in the geothermal waters have mantle origin.

  18. Experiment on the performance improvement of air-to-air heat pump adopting the hot gas bypass method by outdoor fan speed variation

    International Nuclear Information System (INIS)

    This study focuses on the effect of outdoor coil fan speed on the performance variation of the heat pump system by adopting the hot gas bypass method, and on the performance improvement with hot gas bypassing using the time step method to defrost. Tests were conducted for fan speeds 90, 60 and 30% of the normal speed of the outdoor coil together with the stationary case. Performance of the heat pump is compared with the conventional time step defrosting method for coefficient of performance (COP) and total heat capacity. Results show that the integrated heating capacity with hot gas bypassing is highest at 60% (780 rpm) of the fan speed and is 8.6% higher than that of the time step defrosting method. The averaged COP of the heat pump in this case is higher by 3.8% than the time step defrosting method and 2.8% higher than that of the stationary fan

  19. Hot continent: South America is open for fast growth in the natural gas sector

    International Nuclear Information System (INIS)

    Opportunities for participation in the rapid expansion of the natural gas sector in South America following privatization and deregulation initiatives, were examined on a country-by-country basis. In Colombia and Venezuela opportunities exist primarily in domestic development of the gas sector, whereas in the countries of the southern cone - Argentina, Bolivia, Brazil, Chile, Paraguay, Peru and Uruguay - the situation is said to be ripe for energy sector integration. Currently, a second regional pipeline link, with a capacity of 129 Bcf/year, is nearing completion, which will carry gas from west Argentina to Santiago, Chile, to supplement the 77 Bcf/year pipeline carrying gas from Bolivia to the Argentine border, where it connects with a trunk line to supply the Buenos Aires market. A Canadian Energy Research Institute study, to be published in the summer of 1997, focuses on the various pipeline links being put forward to integrate the gas resources in the southern cone with existing and potential gas markets. The integration scenarios examined are predicted to reveal both economic and commercial merit for the pipeline corridors. Canadian energy and pipeline companies are said to be well positioned to take advantage of the opportunities resulting from these initiatives, and to help making the vision of an integrated gas pipeline network in the southern cone of South America a reality

  20. Monopropellant engine investigation for space shuttle reaction control. Volume 2: Design, fabrication, and demonstration test of a catalytic gas generator for the space shuttle APU

    Science.gov (United States)

    1975-01-01

    The capability of a catalytic gas generator to meet the requirement specified for the space shuttle APU is established. A full-scale gas generator, designed to operate at a chamber pressure of 750 psia and a flow rate of 0.36 lbm/sec, was fabricated and subjected to three separate life test series. The nickel foam metal used for catalyst retention was investigated. Inspection of the foam metal following the first life test revealed significant degradation. Consequently an investigation was conducted to determine the mechanism of degradation and to provide an improved foam metal.

  1. Experimental and numerical investigation of the catalytic partial oxidation of methane to synthesis gas for power generation applications[Dissertation 17183

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, A.

    2007-07-01

    The present work addresses the catalytic partial oxidation (CPO) of methane to synthesis gas, with particular emphasis on power generation applications. A combined experimental and numerical investigation of methane partial oxidation to synthesis gas (H{sub 2}, CO) over rhodium-based catalysts has been carried out at pressures of up to 10 bar. The reactivity of the produced hydrogen and the suitably-low light-off temperatures of the CPO reactor, greatly facilitate operation of power generation gas turbines with reduced NO{sub x} emissions, stable operation with low calorific value fuels, and new combustion strategies for efficient CO{sub 2} capture. Those strategies utilize CPO of methane with oxygen (separated from air) and large exhaust gas recycle (H{sub 2}O and CO{sub 2}). An optically accessible catalytic channel-flow reactor was used to carry out Raman spectroscopy of major gas-phase species and laser induced fluorescence (LIF) of formaldehyde, in order to gain fundamental information on the catalytic and gas-phase chemical pathways. Transverse concentration profiles measured by the spontaneous Raman scattering technique determined the catalytic reactivity, while the LIF provided flame shapes and anchoring positions that, in turn, characterized the gaseous reactivity. Comparison between measurements and 2-D CFD computations, led to the validation of detailed catalytic and gas-phase reaction mechanisms. Experiments in a subscale gas-turbine honeycomb catalytic reactor have shown that the foregoing reaction mechanisms were also appropriate under gas-turbine relevant conditions with short reactant residence times. The light-off behavior of the subscale honeycomb reactor was reproduced by transient 2-D CFD computations. Ignition and extinction in CPO was studied. It was shown that, despite the chemical impact of the H{sub 2}O diluent during the transient catalytic ignition event, the light-off times themselves were largely unaffected by the exhaust gas dilution

  2. Search for cold and hot gas in the ram pressure stripped Virgo dwarf galaxy IC3418

    CERN Document Server

    Jachym, P; Ruzicka, A; Sun, M; Combes, F; Palous, J

    2013-01-01

    We present IRAM 30m sensitive upper limits on CO emission in the ram pressure stripped dwarf Virgo galaxy IC3418 and in a few positions covering HII regions in its prominent 17 kpc UV/Ha gas-stripped tail. In the central few arcseconds of the galaxy, we report a possible marginal detection of about 1x10^6 M_sun of molecular gas (assuming a Galactic CO-to-H_2 conversion factor) that could correspond to a surviving nuclear gas reservoir. We estimate that there is less molecular gas in the main body of IC3418, by at least a factor of 20, than would be expected from the pre-quenching UV-based star formation rate assuming the typical gas depletion timescale of 2 Gyr. Given the lack of star formation in the main body, we think the H_2-deficiency is real, although some of it may also arise from a higher CO-to-H_2 factor typical in low-metallicity, low-mass galaxies. The presence of HII regions in the tail of IC3418 suggests that there must be some dense gas; however, only upper limits of < 1x10^6 M_sun were found...

  3. Numerical simulation using CFD software of countercurrent gas-liquid flow in a PWR hot leg under reflux condensation

    Energy Technology Data Exchange (ETDEWEB)

    Utanohara, Yoichi, E-mail: utanohara@inss.co.j [Institute of Nuclear Safety System, Inc., 64 Sata, Mihama-cho, Mikata-gun, Fukui 919-1205 (Japan); Kinoshita, Ikuo, E-mail: kinoshita@inss.co.j [Institute of Nuclear Safety System, Inc., 64 Sata, Mihama-cho, Mikata-gun, Fukui 919-1205 (Japan); Murase, Michio, E-mail: murase@inss.co.j [Institute of Nuclear Safety System, Inc., 64 Sata, Mihama-cho, Mikata-gun, Fukui 919-1205 (Japan); Minami, Noritoshi, E-mail: minami.noritoshi@c4.kepco.co.j [Kansai Electric Power Company, Inc., Mihama-cho, Mikata-gun, Fukui 919-1141 (Japan); Nariai, Toshifumi [Graduate School of Engineering, Kobe University, Nada, Kobe 657-8501 (Japan); Tomiyama, Akio, E-mail: tomiyama@people.kobe-u.ac.j [Graduate School of Engineering, Kobe University, Nada, Kobe 657-8501 (Japan)

    2011-05-15

    Research highlights: The wave height measurements indicated the interfacial drag force mainly consisted of form drag. The resolution of the computational cell affected the CCFL characteristics. The interfacial drag correlations employed in this study can be applied to PWR scale simulations. - Abstract: In order to improve the countercurrent flow model of a transient analysis code, countercurrent air-water tests were previously conducted using a 1/15 scale model of the PWR hot leg and numerical simulations of the tests were carried out using the two-fluid model implemented in the CFD software FLUENT 6.3.26. The predicted flow patterns and CCFL characteristics agreed well with the experimental data. However, the validation of the interfacial drag correlation used in the two-fluid model was still insufficient, especially regarding the applicability to actual PWR conditions. In this study, we measured water levels and wave heights in the 1/15 scale setup to understand the characteristics of the interfacial drag, and we considered a relationship between the wave height and the interfacial drag coefficient. Numerical simulations to examine the effects of cell size and interfacial drag correlations on numerical predictions were conducted under PWR plant conditions. Wave heights strongly related with the water level and interfacial drag coefficient, which indicates that the interfacial drag force mainly consists of form drag. The cell size affected the gas velocity at the onset of flooding in the process of increasing gas flow rate. The gas volumetric fluxes at CCFL predicted using fine cells were higher than those using normal cells. On the other hand, the cell size did not have a significant influence on the process of decreasing gas flow rate. The predictions for the PWR condition using a reference set of interfacial drag correlations agreed well with the Upper Plenum Test Facility data of the PWR scale experiment in the region of medium gas volumetric fluxes. The

  4. Hot-gas cleanup system model development. Volume I. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Ushimaru, K.; Bennett, A.; Bekowies, P.J.

    1982-11-01

    This two-volume report summarizes the state of the art in performance modeling of advanced high-temperature, high-pressure (HTHP) gas cleanup devices. Volume I contains the culmination of the research effort carried over the past 12 months and is a summary of research achievements. Volume II is the user's manual for the computer programs developed under the present research project. In this volume, Section 2 presents background information on pressurized, fluidized-bed combustion concepts, a description of the role of the advanced gas cleanup systems, and a list of advanced gas cleanup systems that are currently in development under DOE sponsorship. Section 3 describes the methodology for the software architecture that forms the basis of the well-disciplined and structured computer programs developed under the present project. Section 4 reviews the fundamental theories that are important in analyzing the cleanup performance of HTHP gas filters. Section 5 discusses the effect of alkali agents in HTHP gas cleanup. Section 6 evaluates the advanced HTHP gas cleanup models based on their mathematical integrity, availability of supporting data, and the likelihood of commercialization. As a result of the evaluation procedure detailed in Section 6, five performance models were chosen to be incorporated into the overall system simulation code, ASPEN. These five models (the electrocyclone, ceramic bag filter, moving granular bed filter, electrostatic granular bed filter, and electrostatic precipitator) are described in Section 7. The method of cost projection for these five models is discussed in Section 8. The supporting data and validation of the computer codes are presented in Section 9, and finally the conclusions and recommendations for the HTHP gas cleanup system model development are given in Section 10. 72 references, 19 figures, 25 tables.

  5. Effect of a condensation utilizer on the operation of steam and hot-water gas-fired boilers

    Science.gov (United States)

    Ionkin, I. L.; Ragutkin, A. V.; Roslyakov, P. V.; Supranov, V. M.; Zaichenko, M. N.; Luning, B.

    2015-05-01

    Various designs for condensation utilizers of the low-grade heat of furnace gases that are constructed based on an open-type heat exchanger are considered. Computational investigations are carried out for the effect of the condensation utilizer with tempering and moistening of air on the operation of steam and hot-water boilers burning natural gas. The investigations are performed based on the predeveloped adequate calculating models of the steam and hot-water boilers in a Boiler Designer program complex. Investigation results for TGM-96B and PTVM-120 boilers are given. The enhancement of the operation efficiency of the condensation utilizer can be attained using a design with tempering and moistening of air supplied to combustion that results in an insignificant increase in the temperature of waste gases. This has no effect on the total operation efficiency of the boiler and the condenser unit, because additional losses with waste gases are compensated owing to the operation of the last. The tempering and moistening of air provide a substantial decrease in the temperature in the zone of active combustion and shortening the nitrogen oxide emission. The computational investigations show that the premoistening of air supplied to combustion makes the technical and economic efficiency of boilers operating with the Condensation Utilizer no worse.

  6. Hot-gas desulfurization. II. Use of gasifier ash in a fluidized-bed process. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Schrodt, J.T.

    1981-02-01

    Three gasifier coal ashes were used as reactant/sorbents in batch fluidized-beds to remove hydrogen sulfide from hot, made-up fuel gases. It is predominantly the iron oxide in the ash that reacts with and removes the hydrogen sulfide; the sulfur reappears in ferrous sulfide. Sulfided ashes were regenerated by hot, fluidizing streams of oxygen in air; the sulfur is recovered as sulfur dioxide, exclusively. Ash sorption efficiency and sulfur capacity increase and stabilize after several cycles of use. These two parameters vary directly with the iron oxide content of the ash and process temperature, but are independent of particle size in the range 0.01 - 0.02 cm. A western Kentucky No. 9 ash containing 22 weight percent iron as iron oxide sorbed 4.3 weight percent sulfur at 1200/sup 0/F with an ash sorption efficiency of 0.83 at ten percent breakthrough. A global, fluidized-bed, reaction rate model was fitted to the data and it was concluded that chemical kinetics is the controlling mechanism with a predicted activation energy of 19,600 Btu/lb mol. Iron oxide reduction and the water-gas-shift reaction were two side reactions that occurred during desulfurization. The regeneration reaction occurred very rapidly in the fluid-bed regime, and it is suspected that mass transfer is the controlling phenomenon.

  7. Effect of hot isostatic pressing on microstructure of cast gas-turbine vanes of K452 alloy

    Institute of Scientific and Technical Information of China (English)

    Jie Li; Chao Yuan; Jianting Guo; Jieshan Hou; Lanzhang Zhou

    2014-01-01

    The effect of hot isostatic pressing (HIP) treatment on microstructure of gas-turbine vanes made of K452 alloy was investigated by OM, SEM and TEM. The results showed that HIP treatment played a great role in the porosity healing processing, where 80%of porosities were eliminated and the diameter of remnant porosities decreased to 10μm. The healing mechanism of the porosities was consistent with existing theories of porosity closure based on vacancy diffusion. According to the result of the tensile test, the plasticity of the alloy was improved as the result of the elimination of the porosities and the improvement of dendritic segregation, while there was not an obvious improvement in the tensile strength after the programmed HIP process. In addition, HIP had a positive effect on narrowing down the dispersion of tensile properties.

  8. The initial conditions and evolution of isolated galaxy models: effects of the hot gas halo

    CERN Document Server

    Hwang, Jeong-Sun; Choi, Jun-Hwan

    2013-01-01

    We construct several Milky Way-like galaxy models containing a gas halo (as well as gaseous and stellar disks, a dark matter halo, and a stellar bulge) following either an isothermal or an NFW density profile with varying mass and initial spin. In addition, galactic winds associated with star formation are tested in some of the simulations. We evolve these isolated galaxy models using the GADGET-3 $N$-body/hydrodynamic simulation code, paying particular attention to the effects of the gas halo on the evolution. We find that the evolution of the models is strongly affected by the adopted gas halo component. The model without a gas halo shows an increasing star formation rate (SFR) at the beginning of the simulation for some hundreds of millions of years and then a continuously decreasing rate to the end of the run at 3 Gyr. On the other hand, the SFRs in the models with a gas halo emerge to be either relatively flat throughout the simulations or increasing over a gigayear and then decreasing to the end. The mo...

  9. Hydrogen sulfide removal from hot coal gas by various mesoporous silica supported Mn2O3 sorbents

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Mn2O3/KIT-1 presented the best desulfurization performance at 600–850 °C. • High sulfur capacity of Mn2O3/KIT-1 correlated closely with 3-D channel of KIT-1. • Desulfurization character depended strongly on framework structure of sorbents. • High steam content suppressed greatly the occurrence of sulfidation reaction. - Abstract: A series of 50 wt% Mn2O3 sorbents was prepared using various mesoporous silica, MCM-41, HMS, and KIT-1 as support. The influence of textural parameters of mesoporous silica, especially type of channel on the desulfurization performance of Mn2O3 sorbents was investigated at 600–850 °C using hot coal gas containing 0.33 vol.% H2S. The fresh and used sorbents were characterized by means of N2-adsorption, x-ray diffraction (XRD), high resolution transmission microscopy (HRTEM) and H2 temperature- programmed reduction (H2-TPR) techniques. The results confirmed that the manganese oxide was dispersed highly in regular pore channel of the mesoporous supports due to high surface area. Compared with the Mn2O3/diatomite, all mesoporous silica supported Mn2O3 sorbents exhibited high breakthrough sulfur capacity and a sharp deactivation rate after the breakthrough point. Compared to Mn2O3/MCM-41 and Mn2O3/HMS sorbent, the Mn2O3/KIT-1 showed better desulfurization performance because of the 3D wormhole-like channel. The high sulfur capacity of the Mn2O3/KIT-1 sorbent was maintained during the eight consecutive desulfurization-regeneration cycles. The Mn2O3/KIT-1 still presented high desulfurization activity when hot coal gas contained low steam (<5%)

  10. USE OF GAS BURNERS TYPE "DAVA" OPERATING UNDER VARIABLE LOAD TO PRODUCE HEAT AND HOT WATER

    Directory of Open Access Journals (Sweden)

    Daud V.

    2014-12-01

    Full Text Available The article brings additional information referred to upgraded gas burners type "DAVA", which are characterized by high performance at variable load. Adaptation of burner operation is carried out automatically. There are presented design features that allow increase of the efficiency and the reliability of these burners at variable load, and reducing natural gas consumption. The range of variation of the coefficient of excess air affects the efficiency of the burner. The experimental results of the tests of gas burners of different power had confirmed the economic effect of the upgraded burners at heat production. It is proved that economic effect increases with increasing of burner output and of operation time during the season.

  11. Absorption signatures of warm-hot gas at low redshift: NeVIII

    CERN Document Server

    Tepper-Garcia, Thorsten; Schaye, Joop

    2013-01-01

    At z14, are only produced in collisionally ionised gas with T=5x10^5 K and log n_H>-4. Metal-rich ([Ne/H]=0), strong (log N~14) absorbers have typical sizes ~10 kpc and likely originate in the immediate vicinity of galaxies. Despite their relatively high total hydrogen column densities (log N_H~20), these strong NeVIII cloudlets account for less than 1% of the cosmic baryon budget. The baryon content of the gas harbouring the NeVIII absorbers is, however, a factor 1/c_L higher. We conclude that strong NeVIII absorbers are robust probes of shock-heated diffuse gas. Spectra with S/N~100 would allow the detection of the weaker systems that trace a substantial fraction of the baryons at low redshift.

  12. Properties of hot gas in halos of active galaxies and clusters of galaxies

    International Nuclear Information System (INIS)

    The importance of the inverse Compton effect in the X-ray emission of cluster galaxies is discussed; the X-ray origin problem from galaxy clusters (spectra and emission mechanisms) is studied. The insufficiency of the X-ray bremsstrahlung emission model in an isothermal gas is proved. The ionized halos in narrow-line galaxies (NLG) are studied; after some general points on NLG, one NLG is described and a brief view an emission mechanism models is given; a detailed study of the galaxy IC 5063 and its nebulosity is given: the ionized gas density is calculated together with the evaporation rate for such clouds

  13. The Cosmic History of Hot Gas Cooling and Radio AGN Activity in Massive Early-Type Galaxies

    Science.gov (United States)

    Danielson, A. L. R.; Lehmer, B. D.; Alexander, D. M.; Brandt, W. M.; Luo, B.; Miller, N.; Xue, Y. Q.; Stott, J. P.

    2012-01-01

    We study the X-ray properties of 393 optically selected early-type galaxies (ETGs) over the redshift range of z approx equals 0.0-1.2 in the Chandra Deep Fields. To measure the average X-ray properties of the ETG population, we use X-ray stacking analyses with a subset of 158 passive ETGs (148 of which were individually undetected in X-ray). This ETG subset was constructed to span the redshift ranges of z = 0.1-1.2 in the approx equals 4 Ms CDF-S and approx equals 2 Ms CDF-N and z = 0.1-0.6 in the approx equals 250 ks E-CDF-S where the contribution from individually undetected AGNs is expected to be negligible in our stacking. We find that 55 of the ETGs are detected individually in the X-rays, and 12 of these galaxies have properties consistent with being passive hot-gas dominated systems (i.e., systems not dominated by an X-ray bright Active Galactic Nucleus; AGN). On the basis of our analyses, we find little evolution in the mean 0.5-2 keY to B-band luminosity ratio (L(sub x) /L(sub Beta) varies as [1 +z]) since z approx equals 1.2, implying that some heating mechanism prevents the gas from cooling in these systems. We consider that feedback from radio-mode AGN activity could be responsible for heating the gas. We select radio AGNs in the ETG population using their far-infrared/radio flux ratio. Our radio observations allow us to constrain the duty cycle history of radio AGN activity in our ETG sample. We estimate that if scaling relations between radio and mechanical power hold out to z approx equals 1.2 for the ETG population being studied here, the average mechanical power from AGN activity is a factor of approx equals1.4 -- 2.6 times larger than the average radiative cooling power from hot gas over the redshift range z approx equals 0-1.2. The excess of inferred AGN mechanical power from these ETGs is consistent with that found in the local Universe for similar types of galaxies.

  14. Evaluation of an all-ceramic tubesheet assembly for a hot gas filter

    Energy Technology Data Exchange (ETDEWEB)

    Bitner, J.L. [Mallett Technology, Inc., Canonsburg, PA (United States); Mallett, R.H. [Mallett Technology, Inc., Research Triangle Park, NC (United States); Eggerstedt, P.M. [Industrial Filter and Pump Mfg. Co., Cicero, IL (United States); Swindeman, R.W. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    A 10-inch thick, all-ceramic tubesheet design is evaluated for differential pressure and thermal conditions. Primary stresses from differential pressure are well within a safe allowable. The calculated peak thermal stresses at local discontinuities approach the modules of rupture for the ceramic material. Kiln tests were performed to demonstrate differential temperatures between hot center and cooler rim do not cause failures or visible tensile cracks. There appear to be mitigating mechanisms and design features in the Industrial Filter and Pump (IF and P) Mfg. Co. all-ceramic tubesheet design concept that add forgiveness in accommodating differential pressure and thermal loading stresses. A material characterization program on the ceramic materials is recommended.

  15. Research on improvement in Zn-based sorbent for hot gas desulfurization

    Institute of Scientific and Technical Information of China (English)

    ZHANG Cui-qing; BU Xue-peng; YING You-ju; PENG Wan-wang

    2005-01-01

    Two Zn-based sorbents, L-991 and L-992 used for hot 9as desulfurization (HGD) were introduced. Zn/Ti ratio of the two sorbent was 1:1 and 2:3 resptively and a certain proportion of Cu and Mn metal oxide were added into L-992, which provided better performance than L-991 in aspects of suitable work temperature, sulfur capacity and agglomeration on the surface of sorbent particles. The evaluation tests were done on both sorbents include multi cycles tests. ARD and SEM analysis were done on fresh and post tests sorbent. During continuous sulfidation/regeneration, the H2S concentration can be reduced from about 10 g/m3 to less than 20 mg/m3, the H2S removal efficiency >99%.

  16. Gas-liquid countercurrent two-phase flow in a PWR hot leg: A comprehensive research review

    Energy Technology Data Exchange (ETDEWEB)

    Deendarlianto, E-mail: deendarlianto@ugm.ac.id [Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Safety Research, P.O. Box 510 119, D-01314 Dresden (Germany); Department of Mechanical and Industrial Engineering, Faculty of Engineering, Gadjah Mada University, Jalan Grafika No. 2, Yogyakarta 55281 (Indonesia); Hoehne, Thomas; Lucas, Dirk [Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Safety Research, P.O. Box 510 119, D-01314 Dresden (Germany); Vierow, Karen [Department of Nuclear Engineering Texas A and M University, 129 Zachry Engineering Center, 3133 TAMU College Station, TX 77843-3133 (United States)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer We review the scientific progress on the CCFL in a PWR hot leg. Black-Right-Pointing-Pointer It includes the experimental data, one-dimensional and CFD models in the open literatures. Black-Right-Pointing-Pointer The weak and strong points of the published works were clarified. Black-Right-Pointing-Pointer The research directions in this field were proposed. - Abstract: Research into gas-liquid countercurrent two-phase flow in a model of pressurized water reactor (PWR) hot leg has been carried out over the last several decades. An extensive experimental data base has been accumulated from these studies, leading to the development of phenomenological correlations and scaling parameters of the countercurrent flow limitation (CCFL). However, most of the proposed correlations apply under a relatively narrow range of conditions, generally limited to the test section conditions and/or geometry. Moreover the development of mechanistic models based on the underlying physical processes has been limited. In contrast to this mechanistic form of modelling, the implementation of computational fluid dynamics (CFD) techniques has also been pursued, but the considerable robust three-dimensional (3D) closure relations for this application remain an unachieved goal due to lack of detailed phenomenological knowledge and consequent application of empirical one-dimensional experimental correlations to the multidimensional problem. This paper presents a comprehensive review of research work on countercurrent gas-liquid two-phase flow in a PWR hot leg and provides direction regarding future research on this topic. In the introductory section, the problems facing current research are described. In the following sections, recent experimental as well as theoretical research achievements are overviewed. In the last section, the problems that remain unsolved are discussed, along with some concluding remarks. It was found that only limited theoretical

  17. Dense Gas in Nearby Galaxies XIV. Detection of hot ammonia in Maffei 2

    CERN Document Server

    Henkel, C; Peck, A B; Falcke, H; Hagiwara, Y

    2000-01-01

    The (J,K) = (1,1), (2,2), (3,3), and (4,4) inversion lines of ammonia (NH3) have been detected toward the nuclear 40'' sized bar of the nearby spiral galaxy Maffei 2. The relative intensities of the ammonia lines are characterized by a rotational temperature of 85 K. This is higher than rotational temperatures measured toward IC342 and most Galactic Center clouds, implying kinetic temperatures of at least 100 K. Since the kinetic temperature of the gas is larger than that of the dust, NH3 is tracing a particularly dense warm gas component that is heated by young massive stars, cloud-cloud collisions, or ion-slip heating in the nuclear starburst. The gas north of the nucleus (V(LSR} = -80 km/s) is more highly excited than the gas further south (+6 km/s). This asymmetry might be related to a pronounced morphological distortion that is observed in the north-eastern part of the galaxy.

  18. Recent federal initiatives to promote unconventional gas: High octane delivery of just hot air?

    Energy Technology Data Exchange (ETDEWEB)

    Griff, M.T.

    1995-10-01

    This paper provides an overview of recent initiatives of the United States which promote greater use of natural gas and unconventional gas as one part of this nations`s larger response to the global warming threat. Measurable increases in greenhouse gas concentrations since the beginning of the industrial revolution have led to the belief in the existence of a global warming problem. The international community has responded to the global warming threat with the United Nations Framework Convention on Climate Change which is directed toward the stabilization of greenhouse gases in the atmosphere. The Climate Change Action Plan is the Clinton Administration`s detailed response to the global warming threat. It is designed to return United States emissions of greenhouse gases to their 1990 levels by the year 2000. The Action Plan targets all greenhouse gases and emphasizes energy efficiency. Significant regulatory reformation designed to increase the efficiency of the natural gas industry has already occurred and will be continued. Recovery of methane emissions from landfills will be encouraged through indentification of suitable sites and use of existing technology and development of new technology. Recovery of methane from coal mining operations will be promoted by targeting 50 of the gassiest mines in the United States. Even if the Action Plan is fully implemented. legitimate questions arise as to whether its goals will be achieved as a result of funding shortfalls.

  19. Toward improved durability in advanced aircraft engine hot sections; Proceedings of the Thirty-third ASME International Gas Turbine and Aeroengine Congress and Exposition, Amsterdam, Netherlands, June 5-9, 1988

    Science.gov (United States)

    Sokolowski, Daniel E. (Editor)

    1988-01-01

    The present conference on durability improvement methods for advanced aircraft gas turbine hot-section components discusses NASA's 'HOST' project, advanced high-temperature instrumentation for hot-section research, the development and application of combustor aerothermal models, and the evaluation of a data base and numerical model for turbine heat transfer. Also discussed are structural analysis methods for gas turbine hot section components, fatigue life-prediction modeling for turbine hot section materials, and the service life modeling of thermal barrier coatings for aircraft gas turbine engines.

  20. Eliminación de Bandas Calientes en Reformador de Gas Natural Elimination of Hot Bands in a Natural Gas Reformer

    Directory of Open Access Journals (Sweden)

    D.J. Correa

    2004-01-01

    Full Text Available El objetivo de este trabajo fue encontrar las causas de la formación de bandas calientes por deposición de coque en un reformador de gas natural, que provoca la salida de servicio de la unidad y mayores costos de producción. Se recurrió a la literatura para determinar las variables que tienen incidencia en esta problemática y se creó un trazador que cuantifica la formación de coque, denominado Índice de Obstrucción. Se analizó sistemáticamente el impacto de las distintas variables y se relacionaron con la evolución del Índice de Obstrucción, siempre tomando información de la propia planta industrial. Descartando todas las hipótesis, excepto la presencia de hidrocarburos livianos, se determinó que el problema de las bandas calientes no se origina en el propio horno de reforma, sino aguas arriba del proceso, en el desulfuradorThe purpose of this study was to find the causes of formation of hot bands due to coke deposition in a natural gas reformer which caused the unit to go out of service, resulting in higher production costs. A literature study was made to determine the variables which affected the incidence of this problem, and to produce an index which quantified the formation of coke, named Obstruction Index. The impact of different variables was systematically analyzed and these variables were related to the evolution of the Obstruction Index, always taking into account the information from the industrial plant studied. All hypotheses were discarded except that relating to the presence of light hydrocarbons. It was determined that the problem of the hot bands did not originate within the reforming unit, but rather upstream of the process in the desulfurization unit

  1. Effect of Mg/Al atom ratio of support on catalytic performance of Co-Mo/MgO-Al2O3 catalyst for water gas shift reaction

    Institute of Scientific and Technical Information of China (English)

    Yixin Lian; Huifang Wang; Quanxing Zheng; Weiping Fang; Yiquan Yang

    2009-01-01

    Co-Mo-based catalysts supported on mixed oxide supports MgO-Al2O3 with different Mg/Al atom ratios for water gas shift reaction were studied by means of TPR, Raman, XPS and ESR. It was found that the octahedral Mo species in oxidized Co-Mo/MgO(x)-Al2O3 catalyst and the contents of Mo5+, Mo4+, S2- and S2-2 species in the functioning catalysts increased with increasing the Mg/Al atom ratio of the support under the studied experimental conditions. This is favorable for the formation of the active Co-Mo-S phase of the catalysts. Catalytic performance testing results showed that the catalysts Co-Mo/MgO-Al2O3 with the Mg/Al atom ratio of the support in the range of 0.475-0.525 exhibited optimal catalytic activity for the reaction.

  2. WLAN Hot Spot services for the automotive and oil industries :a business analysis Or : "Refuel the car with petrol and information, both ways at the gas station"

    NARCIS (Netherlands)

    L-F. Pau (Louis-François); M.H.P. Oremus

    2003-01-01

    textabstractWhile you refuel for gas ,why not refuel for information or download vehicle data ? This paper analyzes in extensive detail the user segmentation by vehicle usage , service offering , and full business models from WLAN hot spot services delivered to vehicles (private, professional , publ

  3. Ram Pressure Stripping of Hot Coronal Gas from Group and Cluster Galaxies and the Detectability of Surviving X-ray Coronae

    CERN Document Server

    Vijayaraghavan, Rukmani

    2015-01-01

    Ram pressure stripping can remove hot and cold gas from galaxies in the intracluster medium (ICM), as shown by observations of X-ray and HI galaxy wakes in nearby clusters of galaxies. However, ram pressure stripping, including pre-processing in group environments, does not remove all the hot coronal gas from cluster galaxies. Recent high-resolution Chandra observations have shown that $\\sim 1 - 4$ kpc extended, hot galactic coronae are ubiquitous in group and cluster galaxies. To better understand this result, we simulate ram pressure stripping of a cosmologically motivated population of galaxies in isolated group and cluster environments. The galaxies and the host group and cluster are composed of collisionless dark matter and hot gas initially in hydrostatic equilibrium with the galaxy and host potentials. We show that the rate at which gas is lost depends on the galactic and host halo mass. Using synthetic X-ray observations, we evaluate the detectability of stripped galactic coronae in real observations ...

  4. Hot Gas in Merging Subgroups; Probing the Early Stages of Structure Formation

    Science.gov (United States)

    Machacek, Marie

    2014-08-01

    To fully understand the growth of large scale structure in hierarchical cosmological models, we must first understand how their building blocks, low mass galaxy subgroups, evolve through mergers. These galaxy subgroups are X-ray faint and difficult to observe at high redshift. The study of near-by subgroup mergers may be used as templates to gain insight into the dominant dynamical processes that are at work in the early universe. We use Chandra observations of edges, tails and wings in a sample of near-by galaxy groups ( Pavo, Telescopium, Pegasus, NGC7618/UGC12491 to measure the properties of the diffuse gas, merger velocities, shocks and non-hydrostatic gas 'sloshing', as their common ICM envelopes evolves.

  5. Experimental Study on Emission Control of Premixed Catalytic Combustion of Natural Gas Using Preheated Air%使用加热空气的预混天然气催化燃烧的实验研究

    Institute of Scientific and Technical Information of China (English)

    许考; 刘中良; 何洪; 程水源; 马重芳

    2007-01-01

    In this paper the premixed catalytic combustion emissions such as CO, unburned hydrocarbon (UHC),NOx and the temperature distribution in the catalytic monolith with ultra low concentration of Pd were studied.Three types of monoliths were used for experiments and the temperature of preheated air was respectively 50℃,100℃ and 200℃. The results showed that preheated air made radial temperature in the catalytic monolith uniform which helped to avoid local hot spots so as to decrease NOx emission. The experiment also proved that the shorter monolith showed much better catalytic combustion performance than longer one and the temperature at the exit of the shorter monolith was relatively lower. On the contrary, the temperature was higher in the longer monolith and the lethal NOx emission was slightly increased.

  6. Experimental and numerical investigation of the catalytic partial oxidation of methane to synthesis gas for power generation applications[Dissertation 17183

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, A.

    2007-07-01

    The present work addresses the catalytic partial oxidation (CPO) of methane to synthesis gas, with particular emphasis on power generation applications. A combined experimental and numerical investigation of methane partial oxidation to synthesis gas (H{sub 2}, CO) over rhodium-based catalysts has been carried out at pressures of up to 10 bar. The reactivity of the produced hydrogen and the suitably-low light-off temperatures of the CPO reactor, greatly facilitate operation of power generation gas turbines with reduced NO{sub x} emissions, stable operation with low calorific value fuels, and new combustion strategies for efficient CO{sub 2} capture. Those strategies utilize CPO of methane with oxygen (separated from air) and large exhaust gas recycle (H{sub 2}O and CO{sub 2}). An optically accessible catalytic channel-flow reactor was used to carry out Raman spectroscopy of major gas-phase species and laser induced fluorescence (LIF) of formaldehyde, in order to gain fundamental information on the catalytic and gas-phase chemical pathways. Transverse concentration profiles measured by the spontaneous Raman scattering technique determined the catalytic reactivity, while the LIF provided flame shapes and anchoring positions that, in turn, characterized the gaseous reactivity. Comparison between measurements and 2-D CFD computations, led to the validation of detailed catalytic and gas-phase reaction mechanisms. Experiments in a subscale gas-turbine honeycomb catalytic reactor have shown that the foregoing reaction mechanisms were also appropriate under gas-turbine relevant conditions with short reactant residence times. The light-off behavior of the subscale honeycomb reactor was reproduced by transient 2-D CFD computations. Ignition and extinction in CPO was studied. It was shown that, despite the chemical impact of the H{sub 2}O diluent during the transient catalytic ignition event, the light-off times themselves were largely unaffected by the exhaust gas dilution

  7. Evidence for the Direct Detection of the Thermal Spectrum of the Non-Transiting Hot Gas Giant HD 88133 b

    Science.gov (United States)

    Piskorz, Danielle; Crockett, Nathan R.; Lockwood, Alexandra; Benneke, Björn; Blake, Geoffrey A.; Barman, Travis S.; Bender, Chad F.; Bryan, Marta; Carr, John S.; Fischer, Debra; Howard, Andrew; Isaacson, Howard T.; Johnson, John A.

    2016-10-01

    We target the thermal emission spectrum of the non-transiting gas giant HD 88133 b with high-resolution near-infrared spectroscopy, by treating the planet and its host star as a spectroscopic binary. For sufficiently deep summed flux observations of the star and planet across multiple epochs, it is possible to resolve the signal of the hot gas giant's atmosphere compared to the brighter stellar spectrum, at a level consistent with the aggregate shot noise of the full data set. To do this, we first perform a principal component analysis to remove the contribution of the Earth's atmosphere to the observed spectra. Then, we use a cross-correlation analysis to tease out the spectra of the host star and HD 88133 b to determine its orbit and identify key sources of atmospheric opacity. In total, six epochs of Keck NIRSPEC L band observations and three epochs of Keck NIRSPEC K band observations of the HD 88133 system were obtained. Based on an analysis of the maximum likelihood curves calculated from the multi-epoch cross correlation of the full data set with two atmospheric models, we report the direct detection of the emission spectrum of the non-transiting exoplanet HD 88133 b and measure a radial projection of its Keplerian orbital velocity, its true mass, its orbital inclination, and dominant atmospheric species. This, combined with eleven years of radial velocity measurements of the system, provides the most up-to-date ephemeris for HD 88133.

  8. Evidence for the Direct Detection of the Thermal Spectrum of the Non-Transiting Hot Gas Giant HD 88133 b

    CERN Document Server

    Piskorz, Danielle; Crockett, Nathan R; Lockwood, Alexandra C; Blake, Geoffrey A; Barman, Travis S; Bender, Chad F; Bryan, Marta L; Carr, John S; Fischer, Debra A; Howard, Andrew W; Isaacson, Howard; Johnson, John A

    2016-01-01

    We target the thermal emission spectrum of the non-transiting gas giant HD 88133 b with high-resolution near-infrared spectroscopy, by treating the planet and its host star as a spectroscopic binary. For sufficiently deep summed flux observations of the star and planet across multiple epochs, it is possible to resolve the signal of the hot gas giant's atmosphere compared to the brighter stellar spectrum, at a level consistent with the aggregate shot noise of the full data set. To do this, we first perform a principal component analysis to remove the contribution of the Earth's atmosphere to the observed spectra. Then, we use a cross-correlation analysis to tease out the spectra of the host star and HD 88133 b to determine its orbit and identify key sources of atmospheric opacity. In total, six epochs of Keck NIRSPEC L band observations and three epochs of Keck NIRSPEC K band observations of the HD 88133 system were obtained. Based on an analysis of the maximum likelihood curves calculated from the multi-epoch...

  9. observations of hot molecular gas emission from embedded low-mass protostars

    DEFF Research Database (Denmark)

    Visser, R.; Kristensen, L. E.; Bruderer, S.;

    2012-01-01

    the observations quantitatively, to investigate the origin of the emission, and to use the lines as probes of the various heating mechanisms. Methods. The model consists of a spherical envelope with a power-law density structure and a bipolar outflow cavity. Three heating mechanisms are considered: passive heating...... such as luminosity and envelope mass. Results. The bulk of the gas in the envelope, heated by the protostellar luminosity, accounts for 3–10% of the CO luminosity summed over all rotational lines up to J = 40–39; it is best probed by low-J CO isotopologue lines such as C18O 2–1 and 3–2. The UV-heated gas and the C......-type shocks, probed by 12CO 10–9 and higher-J lines, contribute 20–80% each. The model fits show a tentative evolutionary trend: the CO emission is dominated by shocks in the youngest source and by UV-heated gas in the oldest one. This trend is mainly driven by the lower envelope density in more evolved...

  10. Dramatically different kinetics and mechanism at solid/liquid and solid/gas interfaces for catalytic isopropanol oxidation over size-controlled platinum nanoparticles.

    Science.gov (United States)

    Wang, Hailiang; Sapi, Andras; Thompson, Christopher M; Liu, Fudong; Zherebetskyy, Danylo; Krier, James M; Carl, Lindsay M; Cai, Xiaojun; Wang, Lin-Wang; Somorjai, Gabor A

    2014-07-23

    We synthesize platinum nanoparticles with controlled average sizes of 2, 4, 6, and 8 nm and use them as model catalysts to study isopropanol oxidation to acetone in both the liquid and gas phases at 60 °C. The reaction at the solid/liquid interface is 2 orders of magnitude slower than that at the solid/gas interface, while catalytic activity increases with the size of platinum nanoparticles for both the liquid-phase and gas-phase reactions. The activation energy of the gas-phase reaction decreases with the platinum nanoparticle size and is in general much higher than that of the liquid-phase reaction which is largely insensitive to the size of catalyst nanoparticles. Water substantially promotes isopropanol oxidation in the liquid phase. However, it inhibits the reaction in the gas phase. The kinetic results suggest different mechanisms between the liquid-phase and gas-phase reactions, correlating well with different orientations of IPA species at the solid/liquid interface vs the solid/gas interface as probed by sum frequency generation vibrational spectroscopy under reaction conditions and simulated by computational calculations.

  11. Comparing the catalytic oxidation of ethanol at the solid-gas and solid-liquid interfaces over size-controlled Pt nanoparticles: striking differences in kinetics and mechanism.

    Science.gov (United States)

    Sapi, Andras; Liu, Fudong; Cai, Xiaojun; Thompson, Christopher M; Wang, Hailiang; An, Kwangjin; Krier, James M; Somorjai, Gabor A

    2014-11-12

    Pt nanoparticles with controlled size (2, 4, and 6 nm) are synthesized and tested in ethanol oxidation by molecular oxygen at 60 °C to acetaldehyde and carbon dioxide both in the gas and liquid phases. The turnover frequency of the reaction is ∼80 times faster, and the activation energy is ∼5 times higher at the gas-solid interface compared to the liquid-solid interface. The catalytic activity is highly dependent on the size of the Pt nanoparticles; however, the selectivity is not size sensitive. Acetaldehyde is the main product in both media, while twice as much carbon dioxide was observed in the gas phase compared to the liquid phase. Added water boosts the reaction in the liquid phase; however, it acts as an inhibitor in the gas phase. The more water vapor was added, the more carbon dioxide was formed in the gas phase, while the selectivity was not affected by the concentration of the water in the liquid phase. The differences in the reaction kinetics of the solid-gas and solid-liquid interfaces can be attributed to the molecular orientation deviation of the ethanol molecules on the Pt surface in the gas and liquid phases as evidenced by sum frequency generation vibrational spectroscopy.

  12. Constraining supernova models using the hot gas in clusters of galaxies

    CERN Document Server

    De Plaa, J; Bleeker, J A M; Vink, J; Kaastra, J S; Méndez, M; Vink, Jacco

    2007-01-01

    The hot Intra-Cluster Medium (ICM) in clusters of galaxies is a very large repository of metals produced by supernovae. We aim to accurately measure the abundances in the ICM of many clusters and compare these data with metal yields produced by supernovae. Using the data archive of the XMM-Newton X-ray observatory, we compile a sample of 22 clusters. We fit spectra extracted from the core regions and determine the abundances of silicon, sulfur, argon, alcium, iron, and nickel. The abundances from the spectral fits are subsequently fitted to supernova yields determined from several supernova type Ia and core-collapse supernova models. We find that the argon and calcium abundances cannot be fitted with currently favoured supernova type Ia models. We obtain a major improvement of the fit, when we use an empirically modified delayed-detonation model that is calibrated on the Tycho supernova remnant. The two modified parameters are the density where the sound wave in the supernova turns into a shock and the ratio ...

  13. VOF Calculations of Countercurrent Gas-Liquid Flow in a PWR Hot Leg

    Directory of Open Access Journals (Sweden)

    M. Murase

    2012-01-01

    Full Text Available We improved the computational grid and schemes in the VOF (volume of fluid method with the standard − turbulent model in our previous study to evaluate CCFL (countercurrent flow limitation characteristics in a full-scale PWR hot leg (750 mm diameter, and the calculated CCFL characteristics agreed well with the UPTF data at 1.5 MPa. In this paper, therefore, to evaluate applicability of the VOF method to different fluid properties and a different scale, we did numerical simulations for full-scale air-water conditions and the 1/15-scale air-water tests (50 mm diameter, respectively. The results calculated for full-scale conditions agreed well with CCFL data and showed that CCFL characteristics in the Wallis diagram were mitigated under 1.5 MPa steam-water conditions comparing with air-water flows. However, the results calculated for the 1/15-scale air-water tests greatly underestimated the falling water flow rates in calculations with the standard − turbulent model, but agreed well with the CCFL data in calculations with a laminar flow model. This indicated that suitable calculation models and conditions should be selected to get good agreement with data for each scale.

  14. Numerical simulation of countercurrent gas-liquid flow in a PWR hot leg using VOF method

    International Nuclear Information System (INIS)

    In order to evaluate flow patterns and CCFL (countercurrent flow limitation) characteristics in a PWR hot leg under reflux condensation, numerical simulations have been done using a two-fluid model and a VOF (volume of fluid) method implemented in the CFD software, FLUENT6.3.26. The two-fluid model gave good agreement with CCFL data under low pressure conditions but did not give good results under high pressure steam-water conditions. On the other hand, the VOF method gave good agreement with CCFL data for tests with a rectangular channel but did not give good results for calculations in a circular channel. Therefore, in this paper, the computational grid and schemes were changed in the VOF method, numerical simulations were done for steam-water flows at 1.5 MPa under PWR full-scale conditions with the inner diameter of 0.75 m, and the calculated results were compared with the UPTF data at 1.5 MPa. As a result, the calculated flow pattern was found to be similar to the flow pattern observed in small-scale air-water tests, and the calculated CCFL characteristics agreed well with the UPTF data at 1.5 MPa except in the region of a large steam volumetric flux. (author)

  15. Carbon formation and metal dusting in hot-gas cleanup systems of coal gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    Tortorelli, P.F.; DeVan, H.J.; Judkins, R.R. [and others

    1995-06-01

    The product gas resulting from the partial oxidation of carboniferous materials in a gasifier consists predominantly of CO, CO{sub 2}, H{sub 2}, H{sub 2}O, CH{sub 4}, and, for air-blown units, N{sub 2} in various proportions at temperatures ranging from about 400 to 1000{degree}C. Depending on the source of the fuel, smaller concentrations of H{sub 2}S, COS, and NH{sub 3} can also be present. The gas phase is typically characterized by high carbon and sulfur, but low oxygen, activities and, consequently, severe degradation of the structural and functional materials used in the gasifier can occur. Therefore, there are numerous concerns about materials performance in coal gasification systems, particularly at the present time when demonstration-scale projects are in or nearing the construction and operation phases. This study focused on the subset of materials degradation phenomena resulting from carbon formation and carburization processes, which are related to potential operating problems in certain gasification components and subsystems. More specifically, it examined the current state of knowledge regarding carbon deposition and a carbon-related degradation phemonenon known as metal dusting as they affect the long-term operation of the gas clean-up equipment downstream of the gasifier and addressed possible means to mitigate the degradation processes. These effects would be primarily associated with the filtering and cooling of coal-derived fuel gases from the gasifier exit temperature to as low as 400{degree}C. However, some of the consideratins are sufficiently general to cover conditions relevant to other parts of gasification systems.

  16. Hot gas in the galaxy: what do we know for sure?

    Directory of Open Access Journals (Sweden)

    W. T. Sanders

    2000-01-01

    Full Text Available En la d ecada pasada se lograron grandes avances en nuestra concepci on del gas interestelar caliente de la V a L actea. El Di use X-ray Spectrometer obtuvo espectros del plano gal actico (esto es, de la Burbuja Local, en el rango 0.15{0.28 keV, que muestran l neas y mezclas de l neas de emisi on. Los espectros con rman que el fondo de rayos-X suaves, en estas energ as, es de origen t ermico a aproximadamente 106 K, pero el espectro no puede ser bien ajustado con los modelos de emisi on de plasma existentes. Los datos del sat elite ROSAT, tanto de muestreo de todo el cielo como de observaciones puntuales, restringen las distancias del gas que emite dentro de la Burbuja Local, el medio interestelar local y el halo. Los datos con rman que la Burbuja Local tiene un tama~no de 100 pc y que el halo gal actico tiene dos componentes de gas caliente; una componente muy inhomog enea de 106 K y otra componente m as caliente, de varios 106 K, cuya distribuci on es suave y sigue a la estructura general de la Galaxia. El sat elite ASCA ha detectado emisi on de plasmas a m as de 107 K en la cresta gal actica, en dos regiones del centro gal actico y en el bulbo. M as recientemente, el micro calor metro del experimento Wisconsin/Goddard con cohetes observ o el espectro de la emisi on difusa en (l; b (90 ; 60 , con un campo visual de 1 sr en el rango espectral 0.1{1 keV y con una resoluci on de 8 eV. Las l neas de O VII y O VIII son detectadas, pero s olo se obtienen l mites superiores para las l neas esperadas de Fe XVII.

  17. Hot gas ingestion test results of a two-poster vectored thrust concept with flow visualization in the NASA Lewis 9- x 15-foot low speed wind tunnel

    Science.gov (United States)

    Johns, Albert L.; Neiner, George; Bencic, Timothy J.; Flood, Joseph D.; Amuedo, Kurt C.; Strock, Thomas W.

    1990-01-01

    A 9.2 percent scale Short Takeoff and Vertical Landing (STOVL) hot gas ingestion model was designed and built by McDonnell Douglas Corporation (MCAIR) and tested in the Lewis Research Center 9 x 15 foot Low Speed Wind Tunnel (LSWT). Hot gas ingestion, the entrainment of heated engine exhaust into the inlet flow field, is a key development issure for advanced short takeoff and vertical landing aircraft. Flow visualization from the Phase 1 test program, which evaluated the hot ingestion phenomena and control techniques, is covered. The Phase 2 test program evaluated the hot gas ingestion phenomena at higher temperatures and used a laser sheet to investigate the flow field. Hot gas ingestion levels were measured for the several forward nozzle splay configurations and with flow control/life improvement devices (LIDs) which reduced the hot gas ingestion. The model support system had four degrees of freedom - pitch, roll, yaw, and vertical height variation. The model support system also provided heated high-pressure air for nozzle flow and a suction system exhaust for inlet flow. The test was conducted at full scale nozzle pressure ratios and inlet Mach numbers. Test and data analysis results from Phase 2 and flow visualization from both Phase 1 and 2 are documented. A description of the model and facility modifications is also provided. Headwind velocity was varied from 10 to 23 kn. Results are presented over a range of nozzle pressure ratios at a 10 kn headwind velocity. The Phase 2 program was conducted at exhaust nozzle temperatures up to 1460 R and utilized a sheet laser system for flow visualization of the model flow field in and out of ground effects. The results reported are for nozzle exhaust temperatures up to 1160 R. These results will contain the compressor face pressure and temperature distortions, the total pressure recovery, the inlet temperature rise, and the environmental effects of the hot gas. The environmental effects include the ground plane contours

  18. Long way to go: how outflows from large galaxies propagate through the hot halo gas

    CERN Document Server

    Sarkar, Kartick Chandra; Sharma, Prateek; Shchekinov, Yuri

    2014-01-01

    Abridged Abstract: Using hydrodynamic simulations, we study the mass loss rate due to supernova-driven outflows from Milky Way type disk galaxies. Our goal is to relate the wind mass loss rates at different radii and times, and the central star formation rate (SFR). In particular, we study the role of the often-neglected extended halo gas. We find that the time averaged mass loss rate at inner radii scales roughly linearly with the star formation rate ($\\dot{M} \\propto {\\rm SFR}^{0.75}$), and that the mass loading factor at the virial radius is roughly half its value at the inner radii. The temperature distribution of the outflowing material in the very inner region ($\\sim $10 kpc) is found to be bimodal in nature , peaking at $10^5$ K and $10^{6.5}$ K, responsible for optical and X-ray emission, respectively. The contribution of cold/warm gas with temperature $\\le 10^{5.5}$ K to the outflow rate within 10 kpc is $\\approx 0.3\\hbox{--}0.5$. This helps us to connect the warm mass loading factor ($\\eta_{3e5}$, e...

  19. The performance of a monolithic catalytic converter of automobile exhaust gas with oscillatory feeding of CO, NO, and O{sub 2}. A modelling study

    Energy Technology Data Exchange (ETDEWEB)

    Nievergeld, A.J.L.; Hoebink, J.H.B.J.; Marin, G.B. [Lab. voor Chemische Technologie, Eindhoven Univ. of Technology, Eindhoven (Netherlands)

    1995-12-31

    An isothermal monolithic catalytic converter of automobile exhaust gas was modelled in order to assess the effects of oscillatory feeding of CO, O{sub 2} and NO on the performance of the reactor. The influence of the temperature, frequency, and amplitude on the time average conversions was investigated. An improvement relative to the steady state conversion of 8% for CO and 30% for NO can be obtained. An explanation is given in terms of strongly changing surface coverage during cycling of the feed concentrations. 9 figs., 5 tabs., 16 refs.

  20. The Energy Efficiency of Hot Water Production by Gas Water Heaters with a Combustion Chamber Sealed with Respect to the Room

    Directory of Open Access Journals (Sweden)

    Grzegorz Czerski

    2014-08-01

    Full Text Available This paper presents investigative results of the energy efficiency of hot water production for sanitary uses by means of gas-fired water heaters with the combustion chamber sealed with respect to the room in single-family houses and multi-story buildings. Additionally, calculations were made of the influence of pre-heating the air for combustion in the chimney and air supply system on the energy efficiency of hot water production. CFD (Computational Fluid Dynamics software was used for calculation of the heat exchange in this kind of system. The studies and calculations have shown that the use of gas water heaters with a combustion chamber sealed with respect to the room significantly increases the efficiency of hot water production when compared to traditional heaters. It has also been proven that the pre-heating of combustion air in concentric chimney and air supply ducts essentially improves the energy efficiency of gas appliances for hot water production.

  1. Experimental analysis of an air-source transcritical CO2 heat pump water heater using the hot gas bypass defrosting method

    International Nuclear Information System (INIS)

    When an air-source CO2 heat pump water heater operates at low ambient temperatures in cold regions in winter, frost can form on the coil surface of its outdoor evaporator. The frost substantially affects the operating performance and energy efficiency of CO2 heat pump water heaters and hence periodic defrosting is essential. In this paper, defrosting characteristics of an air-source CO2 heat pump water heater using the hot gas bypass defrosting method is experimentally studied at different ambient conditions. An experimental setup is developed for this purpose and experimental procedures are detailed. Thereafter, the pressure and temperature in the outdoor evaporator, at the compressor and gas cooler outlets are evaluated during the defrosting period. An energy analysis is then performed of different system components during the defrosting process. Results indicate that 35% of the supplied energy is used for melting the frost, and 7.6% is used to heat the evaporator tubes and fins. About 57.4% of the supplied energy is consumed to increase the internal energy of the gas cooler. The typical efficiency of the hot gas bypass defrosting method applied in the CO2 heat pump water heater ranges from 30 to 40%. It increases with increasing dry bulb temperature, and decreasing relative humidity. - Highlights: • Hot gas bypass defrosting method for transcritical CO2 heat pumps was studied. • An experimental setup was established in an environmental laboratory. • The temperature, pressure and energy consumptions in the system were analysed. • The efficiency of hot gas bypass defrosting method ranged from 30 to 40%. • The effect of ambient conditions on defrosting efficiency was investigated

  2. Characterization of gas metal arc welded hot rolled DP600 steel

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, K.; Ramazani, A.; Yang, L.; Prahl, U.; Bleck, W. [RWTH Aachen University, Institute for Ferrous Metallurgy (IEHK) (Germany); Reisgen, U.; Schleser, M.; Abdurakhmanov, A. [RWTH Aachen University, Welding and Joining Institute (ISF) (Germany)

    2011-12-15

    Dual-phase (DP) steels are suitable candidates for automotive applications due to their high strength and ductility. These advanced mechanical properties result from the special microstructure of the DP steel with 5{proportional_to}20% martensite phase in a soft ferrite matrix. However, during welding, which is an important process in automotive industry, this special microstructure is destroyed. In this research the characterization of Gas Metal Arc (GMA) welded joining zones was performed by optical microscopy and hardness mapping. Tensile tests were also performed keeping the welded portion in the gauge length. Scanning Electron Microscopy (SEM) was used for the fracture investigation. From the characterization and tensile tests, the soften zones were found, which are caused by the tempered martensite and larger ferrite grain size than that in base metal. Furthermore, GMA welding make a large Heat Affected Zone (HAZ). (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Comparative study on the corrosion behavior of the cold rolled and hot rolled low-alloy steels containing copper and antimony in flue gas desulfurization environment

    Science.gov (United States)

    Park, S. A.; Kim, J. G.; He, Y. S.; Shin, K. S.; Yoon, J. B.

    2014-12-01

    The correlation between the corrosion and microstructual characteristics of cold rolled and hot rolled low-alloy steels containing copper and antimony was established. The corrosion behavior of the specimens used in flue gas desulfurization systems was examined by electrochemical and weight loss measurements in an aggressive solution of 16.9 vol % H2SO4 + 0.35 vol % HCl at 60°C, pH 0.3. It has been shown that the corrosion rate of hot rolled steel is lower than that of cold rolled steel. The corrosion rate of cold rolled steel was increased by grain refinement, inclusion formation, and preferred grain orientation.

  4. Removal of hydrogen sulfide from hot fuel gas using an electrochemical membrane system

    Science.gov (United States)

    Burke, Adrian Alan

    Sulfur is a natural contaminant in nearly all fossil fuel supplies. When a fuel stream is gasified or reformed, the sulfur manifests itself in the form of hydrogen sulfide, H2S. Extraordinary effort is put forth to remove H2S to at least ppm levels before the fuel can be used for power generation. To compete with current methods, an electrochemical membrane system (EMS) is now being studied to remove H2S in one step at high temperature. This process offers continuous H2S removal at an estimated operating cost of $0.32/kg H2S removed and a capital cost that is roughly half that of a Claus plant with tail-gas clean-up. Other advantages are the considerable savings in energy and space compared to current methods. A bench scale set-up was constructed to test the cell performance at 600-700°C and 1 atm. The typical fuel stream inlet proportions were 34% CO, 22% CO2, 35% H2, 8% H2O, and 450-2000 ppm H2S. The fundamental transport restrictions for sulfur species in an electrochemical cell were examined. Temperature and membrane thickness were varied to examine how these parameters affect the maximum flux of H 2S removal. It was found that higher temperature allows more sulfide species to enter the electrolyte, thus increasing the sulfide flux across the membrane and raising the maximum flux of H2S removal. Also, membrane thickness was found to be a critical parameter in cell design. A thinner membrane decreases the distance that sulfide ions must travel to be oxidized at the anode. These results identify sulfide diffusion across the membrane as the rate-limiting step in H2S removal. The maximum H2S removal flux of 1.1 x 10-6 gmol H2S min-1 cm-2 (or 3.5 mA cm-2) was obtained at 650°C, with a membrane that was 0.9 mm thick, 36% porous, and had an estimated tortuosity of 3.6. Another focus of this thesis was to examine the stability of cathode materials in full cell trials. A major hurdle that remains in process scale-up is cathode selection, as the lifetime of the cell

  5. The Thermochemical Degradation of Hot Section Materials for Gas Turbine Engines in Alternative-Fuel Combustion Environments

    Science.gov (United States)

    Montalbano, Timothy

    Gas turbine engines remain an integral part of providing the world's propulsion and power generation needs. The continued use of gas turbines requires increased temperature operation to reach higher efficiencies and the implementation of alternative fuels for a lower net-carbon footprint. This necessitates evaluation of the material coatings used to shield the hot section components of gas turbines in these new extreme environments in order to understand how material degradation mechanisms change. Recently, the US Navy has sought to reduce its use of fossil fuels by implementing a blended hydroprocessed renewable diesel (HRD) derived from algae in its fleet. To evaluate the material degradation in this alternative environment, metal alloys are exposed in a simulated combustion environment using this blended fuel or the traditional diesel-like fuel. Evaluation of the metal alloys showed the development of thick, porous scales with a large depletion of aluminum for the blend fuel test. A mechanism linking an increased solubility of the scale to the blend fuel test environment will be discussed. For power generation applications, Integrated Gasification Combined Cycle (IGCC) power plants can provide electricity with 45% efficiency and full carbon capture by using a synthetic gas (syngas) derived from coal, biomass, or another carbon feedstock. However, the combustion of syngas is known to cause high water vapor content levels in the exhaust stream with unknown material consequences. To evaluate the effect of increased humidity, air-plasma sprayed (APS), yttria-stabilized zirconia (YSZ) is thermally aged in an environment with and without humidity. An enhanced destabilization of the parent phase by humid aging is revealed by x-ray diffraction (XRD) and Raman spectroscopy. Microstructural analysis by transmission electron microscopy (TEM) and scanning-TEM (STEM) indicate an enhanced coarsening of the domain structure of the YSZ in the humid environment. The enhanced

  6. Dense gas in nearby galaxies XV. Hot ammonia in NGC253, Maffei2 and IC342

    CERN Document Server

    Mauersberger, R; Weiss, A; Peck, A B; Hagiwara, Y

    2003-01-01

    The detection of NH3 inversion lines up to the (J,K)=(6,6) level is reported toward the central regions of the nearby galaxies NGC253, Maffei2, and IC342. The observed lines are up to 406K (for (J,K)=(6,6)) and 848K (for the (9,9) transition) above the ground state and reveal a warm (T_kin= 100 - 140 K) molecular component toward all galaxies studied. The tentatively detected (J,K)=(9,9) line is evidence for an even warmer (>400K) component toward IC342. Toward NGC253, IC342 and Maffei2 the global beam averaged NH3 abundances are 1-2 10^-8, while the abundance relative to warm H2 is around 10^-7. The temperatures and NH3 abundances are similar to values found for the Galactic central region. C-shocks produced in cloud-cloud collisions can explain kinetic temperatures and chemical abundances. In the central region of M82, however, the NH3 emitting gas component is comparatively cool (~ 30K). It must be dense (to provide sufficient NH3 excitation) and well shielded from dissociating photons and comprises only a...

  7. Change On The S-Z Effect Induced By The Cooling Flow CF On The Hot Electronic Gas At The Center OF The Clusters Of Galaxies

    Directory of Open Access Journals (Sweden)

    Enkelejd Caca

    2015-06-01

    Full Text Available ABSTRACT Building more accurate profiles for temperature and density of hot electronic gas concentrated in the center of clusters of galaxies is a constant problem in survey of Sunyeav Zeldovich effect SZ. An effect that consists in the inverse Compton effect of the hot electronic gas interacting with Cosmic Microwave Back- ground CMB photons passing through Intra Cluster Medium ICM. So far the Isothermal model is used for temperature profiling in the calculation of the inverse Compton effect but based on the recent improved observations from satellites which showed that the hot electronic gas presents a feature called Cooling Flow CF. Temperatures in this model differs towards the edges of the Clusters of Galaxies leading to a change on the Compton parameter in comparison with Isothermal model. In this paper are processed data provided by X-ray satellite Chandra. The X-ray analysis is based on two models for the electron density and temperature profile. A sample of 12 clusters of galaxies are analyzed and by building the temperature profiles using CF model the differences on the Compton parameter are 10-100 in comparison with Isothermal model. Therefore to increase the accuracy of evaluation of the Compton parameter we should take into account the change of the electronic gas tempera- ture change that affect changes in both CMB spectrum and temperature from SZ effect.

  8. Effect of preparation conditions on the catalytic performance of cobalt manganese oxide catalysts for conversion of synthesis gas to light olefins

    Energy Technology Data Exchange (ETDEWEB)

    Mirzaei, Ali A.; Faizi, Mostafa; Habibpour, Razieh [Department of Chemistry, Faculty of Sciences, University of Sistan and Baluchestan, Zahedan 98135-674 (Iran, Islamic Republic of)

    2006-06-07

    Cobalt manganese oxides are prepared using a co-precipitation procedure and studied for the conversion of synthesis gas to light olefins. In particular, the effect of a range of preparation variables is investigated in detail. The variables investigated include the precipitate ageing time, pH and temperature of precipitation, the [Co]/[Mn] ratio of the precipitation solution and also reactor conditions such as reaction temperature and H{sub 2}/CO molar feed ratio. The effect of different supports on the activity and selectivity of catalysts are also studied. The optimum preparation conditions are identified with respect to catalytic performance for the conversion of synthesis gas to ethylene and propylene. The results are interpreted in terms of the structure of the active catalyst. Generally it has been concluded that catalysts containing cobalt manganese mixed phases are found to be the most active. (author)

  9. The Influence of Coronal Mass Ejections on the Gas Dynamics of the Atmosphere of a "Hot~Jupiter" Exoplanet

    CERN Document Server

    Bisikalo, D V

    2016-01-01

    The results of three-dimensional numerical simulations of the gas dynamics of the atmosphere of a "hot Jupiter" exoplanet during the passage of a coronal mass ejection (CME) from the central star are presented. These computations assumed the parameters for the stellar wind and the CME to be typical of the solar values. The characteristic variations of the flow pattern are considered for quasi-closed and closed (but appreciably distorted by the gravitational influence of the star) gaseous envelopes of the exoplanet. It is shown that a typical CME is sufficient to tear off the outer part of an asymmetric envelope that is located beyond the Roche lobe and carry it away from the exoplanet. This leads to a substantial increase in the mass-loss rate from the exoplanet envelope during the passage of CMEs. The mass-loss rate grows by about a factor of 11 for a closed envelope, and by about a factor of 14 for a quasi-closed envelope. Possible evolutionary consequences of the loss of part of the atmosphere during the p...

  10. Development of novel copper-based sorbents for hot-gas cleanup. Technical report, March 1, 1992--May 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Abbasian, J.; Hill, A.H.; Wangerow, J.R. [Institute of Gas Technology, Chicago, IL (United States); Flytzani-Stephanopoulos, M.; Bo, L.; Patel, C. [Massachusetts Inst. of Tech., Cambridge, MA (United States)

    1992-10-01

    The objective of this investigation is to evaluate several novel copper-based binary oxides for their suitability as regenerable sorbents for hot gas cleanup application in the temperature range of 650{degrees} to 850{degrees}C. During this quarter cyclic sulfidation/regeneration tests of the sorbents Cu{sub 2}Cr-O and Cu-Ce-0 were conducted using different compositions of the feed gases to investigate the effects of H{sub 2}0, H{sub 2} and CO. These tests were conducted in a packed-bed microreactor at 850{degrees}C. The results of these tests showed that H{sub 2} and CO (along with C02) had a significant effect on the H{sub 2}S pre-breakthrough levels, whereas H{sub 2}0 did not have an effect. The physical properties of the fresh and reacted samples of the Cu-2Cr-O and Cu-Ce-0 sorbents prepared in this program and used in the cyclic sulfidation/regeneration tests were also measured. In addition, sulfidation/regeneration tests were conducted using two commercial copper chromite sorbents (G-13 and G-89, United Catalyst, Inc.) and a zinc titanate sorbent (L-3014) in a one-inch fluidized-bed reactor at 650{degrees}C. The G-13 sorbent appears to have a much higher sulfur capacity than the G-89 sorbent.

  11. Composition modification of zinc titanate sorbents for hot gas desulfurization. Technical report, March 1--May 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Swisher, J.H.

    1995-12-31

    For new coal gasification systems, zinc titanate sorbents are being developed to remove sulfur from the hot product gas prior to its use in combined cycle turbines and high temperature fuel cells. Although most of the properties of these sorbents are very attractive, there are still concerns about durability over many sulfidation-regeneration cycles and zinc losses due to vaporization. Doping the zinc titanate with other metal ions could alleviate both concerns, which are the objectives of this project. After a screening study was completed, it was decided that Cr offered more promise as a dopant than Ni, Cu, Mg, and Al. Therefore six new sorbent formulations containing Cr were prepared, and they are now being evaluated with a series of bulk density, X-ray diffraction, crush strength and thermogravimetric analysis (TGA) measurements. Results to date suggest that, while Zn vaporization losses can be reduced with Cr additions, a penalty in chemical reactivity occurs. A fixed bed test was also completed this quarter on a Cr-containing formulation. The H{sub 2}S breakthrough time was about 11 hours, and utilization of Zn in the sorbent was 60.5%.

  12. X-ray emission of the hot gas and of accelerated particles in supernova remnants

    International Nuclear Information System (INIS)

    The current observations seem to support the theory that the shock wave of supernova remnants accelerate electrons (representing about 1% of cosmic rays) of the interstellar medium up to energies of about 1015 eV. However there is still no solid evidence that supernova remnants also accelerate protons (major component of cosmic rays). The X-ray observations of those supernova remnants with the satellite XMM-Newton can provide crucial information on the acceleration mechanisms and on this population of accelerated particles. This thesis presents the X-ray analysis of the supernova remnants RX J1713.7-3946 and SN 1006 for which it has been shown that they accelerate electrons efficiently. As a result, these objects are very good targets to compare the theoretical models of acceleration to the observation. For the first object, I constructed through new XMM-Newton observations, the first high-angular resolution mosaic of the entire supernova remnant. I then compared the X- and gamma-ray emission of this object in order to understand the nature of the gamma-ray emission. This spectral and morphological comparison allowed me to discuss the two possible origins of the gamma-ray radiation (issued by electrons or by protons). For SN 1006, I studied the density of the ambient medium in which the shock wave propagates. This density is a key parameter for the hydrodynamical evolution of the remnant and for studying a future gamma-ray emission. The study of X-ray emission of the gas heated by the shock wave allowed me to better estimate of the value of the density so far poorly constrained for this object. (author)

  13. Catalytic Combustion of Gasified Waste

    Energy Technology Data Exchange (ETDEWEB)

    Kusar, Henrik

    2003-09-01

    This thesis concerns catalytic combustion for gas turbine application using a low heating-value (LHV) gas, derived from gasified waste. The main research in catalytic combustion focuses on methane as fuel, but an increasing interest is directed towards catalytic combustion of LHV fuels. This thesis shows that it is possible to catalytically combust a LHV gas and to oxidize fuel-bound nitrogen (NH{sub 3}) directly into N{sub 2} without forming NO{sub x} The first part of the thesis gives a background to the system. It defines waste, shortly describes gasification and more thoroughly catalytic combustion. The second part of the present thesis, paper I, concerns the development and testing of potential catalysts for catalytic combustion of LHV gases. The objective of this work was to investigate the possibility to use a stable metal oxide instead of noble metals as ignition catalyst and at the same time reduce the formation of NO{sub x} In paper II pilot-scale tests were carried out to prove the potential of catalytic combustion using real gasified waste and to compare with the results obtained in laboratory scale using a synthetic gas simulating gasified waste. In paper III, selective catalytic oxidation for decreasing the NO{sub x} formation from fuel-bound nitrogen was examined using two different approaches: fuel-lean and fuel-rich conditions. Finally, the last part of the thesis deals with deactivation of catalysts. The various deactivation processes which may affect high-temperature catalytic combustion are reviewed in paper IV. In paper V the poisoning effect of low amounts of sulfur was studied; various metal oxides as well as supported palladium and platinum catalysts were used as catalysts for combustion of a synthetic gas. In conclusion, with the results obtained in this thesis it would be possible to compose a working catalytic system for gas turbine application using a LHV gas.

  14. Influence of size-induced oxidation state of platinum nanoparticles on selectivity and activity in catalytic methanol oxidation in the gas phase.

    Science.gov (United States)

    Wang, Hailiang; Wang, Yihai; Zhu, Zhongwei; Sapi, Andras; An, Kwangjin; Kennedy, Griffin; Michalak, William D; Somorjai, Gabor A

    2013-06-12

    Pt nanoparticles with various sizes of 1, 2, 4, and 6 nm were synthesized and studied as catalysts for gas-phase methanol oxidation reaction toward formaldehyde and carbon dioxide under ambient pressure (10 Torr of methanol, 50 Torr of oxygen, and 710 Torr of helium) at a low temperature of 60 °C. While the 2, 4, and 6 nm nanoparticles exhibited similar catalytic activity and selectivity, the 1 nm nanoparticles showed a significantly higher selectivity toward partial oxidation of methanol to formaldehyde, but a lower total turnover frequency. The observed size effect in catalysis was correlated to the size-dependent structure and oxidation state of the Pt nanoparticles. X-ray photoelectron spectroscopy and infrared vibrational spectroscopy using adsorbed CO as molecular probes revealed that the 1 nm nanoparticles were predominantly oxidized while the 2, 4, and 6 nm nanoparticles were largely metallic. Transmission electron microscopy imaging witnessed the transition from crystalline to quasicrystalline structure as the size of the Pt nanoparticles was reduced to 1 nm. The results highlighted the important impact of size-induced oxidation state of Pt nanoparticles on catalytic selectivity as well as activity in gas-phase methanol oxidation reactions. PMID:23701488

  15. Effect of Al Hot-Dipping on High-Temperature Corrosion of Carbon Steel in N2/0.1% H2S Gas

    Directory of Open Access Journals (Sweden)

    Muhammad Ali Abro

    2016-02-01

    Full Text Available High-temperature corrosion of carbon steel in N2/0.1% H2S mixed gas at 600–800 °C for 50–100 h was studied after hot-dipping in the aluminum molten bath. Hot-dipping resulted in the formation of the Al topcoat and the Al-Fe alloy layer firmly adhered on the substrate. The Al-Fe alloy layer consisted primarily of a wide, tongue-like Al5Fe2 layer and narrow Al3Fe layer. When corroded at 800 °C for 100 h, the Al topcoat partially oxidized to the protective but non-adherent α-Al2O3 layer, and the interdiffusion converted the Al-Fe alloy layer to an (Al13Fe4, AlFe3-mixed layer. The interdiffusion also lowered the microhardness of the hot-dipped steel. The α-Al2O3 layer formed on the hot-dipped steel protected the carbon steel against corrosion. Without the Al hot-dipping, the carbon steel failed by forming a thick, fragile, and non-protective FeS scale.

  16. Summary on Characteristics and Applications for Low -Carbon Catalytic Combustion of Natural Gas%天然气低碳催化燃烧特性与应用*

    Institute of Scientific and Technical Information of China (English)

    张世红; Valerie Dupont; Alan Williams

    2013-01-01

    Lower activation energies of combustion reaction allows reactions occurring at very small hydrocarbons concentration in air, therefore the adiabatic reaction temperature is very low and below the threshold of NOx formation. Oxidation can be complete even when at extremely small fuel concentrations in air, therefore products--CO and unburned hydrocarbons of incomplete combustion do not form. Combustion can occur outside of normal gas phase flammability limits, therefore the combustion can be more stable. According to the modelling results obtained with the detailed chemical mechanism, the Pt surface reactions inhibited in several ways the extent of the gas-phase oxidation and increased the surface temperature of homogeneous ignition. Due to the theory, several catalytic combustion burners of natural gas were designed and studied. The operating conditions verified "near zero" pollutant emissions that only a catalytic combustion process can achieve at present. As low-carbon strategies, the application prospect of national gas catalytic combustion boiler, oven and furnace were discussed.%  催化燃烧反应较低的活化能容许反应在贫碳氢化合物浓度下发生,因此绝热反应的温度低于NOx形成的限制,并完全氧化,不形成CO和未完全燃烧的碳氢化合物,燃烧发生在常规气相易燃极限之外,因此燃烧更加稳定。根据分步化学机理方法模拟出的结果可以得出,铂表面的异相反应抑制了气相氧化反应的程度,并且提高了单相点燃的表面温度。在此理论的指导下,进行了多种天然气催化燃烧装置的设计和研究,催化燃烧过程可达到近零污染排放。作为低碳战略,对天然气催化燃烧锅炉、烤箱和炉窑的应用前景进行了讨论。

  17. Recent advances in AFB biomass gasification pilot plant with catalytic reactors in a downstream slip flow

    Energy Technology Data Exchange (ETDEWEB)

    Aznar, M.P.; Gil, J.; Martin, J.A.; Frances, E.; Olivares, A.; Caballero, M.A.; Perez, P. [Saragossa Univ. (Spain). Dept. of Chemistry and Environment; Corella, J. [Madrid Univ. (Spain)

    1996-12-31

    A new 3rd generation pilot plant is being used for hot catalytic raw gas cleaning. It is based on a 15 cm. i.d. fluidized bed with biomass throughputs of 400-650 kg/h.m{sup 2}. Gasification is performed using mixtures of steam and oxygen. The produced gas is passed in a slip flow by two reactors in series containing a calcined dolomite and a commercial reforming catalyst. Tars are periodically sampled and analysed after the three reactors. Tar conversions of 99.99 % and a 300 % increase of the hydrogen content in the gas are obtained. (author) (2 refs.)

  18. Hot tapping and plugging in gas pipeline - GASCAB-I and GASDUC-I; Furacao em carga e plugueamento em gasodutos - GASCAB-I e GASDUC-I

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Jeziel; Ciuffo, Mauro Cunha; Santa Cruz, Sergio de Freitas [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2003-07-01

    It is difficult to accomplish interventions avoiding the shutdown on of the main lines during the operation of process plants or gas pipelines. It involves unit halt as well supply contract interruption, which can result heavy financial penalties with fines or cost due to profit loss. In such case it is necessary to use special techniques as hot tapping or line plugging. This paper aim to present the technical feasibility of applying line-plugging technique in a gas pipeline submitted to high pressure (82 kg f/cm{sup 2}) in non-straight section. It also presents the technical feasibility of repairing the fastening system of the connection plug. (author)

  19. The hot gas cleaning with multifunctional sorbent technique at 1-20 bar pressure; Kaasujen kuumapuhdistus multifunktionaalisella sorbenttitekniikalla 1-20 bar:n paineessa

    Energy Technology Data Exchange (ETDEWEB)

    Jaanu, K.; Orjala, M.; Paakkinen, K.; Rantanen, J. [VTT Energy, Espoo (Finland)

    1996-12-01

    The aim of the research was to study the simultaneous hot gas cleanup of alkali metals and selected heavy metals under pressure of 1-20 bar using multifunctional sorbent technology, to investigate effects of it on sulfur and nitrogen emissions and to improve the total efficiency of the hot gas cleanup method by reducing the concentrations of harmful components to the level required by the gas turbines. The research has started in the year 1993. The optimization of the test facility at 900 deg C and 20 bar has been accomplished, as targeted. The main topics have been the alkali metals. The main targets of the year 1994 was to concentrate on the research of sorbent effectiveness to remove the impurities like alkalies etc. from the flue gas. Furthermore researches on kinetics and mechanisms were started. The results showed that the developed multifunctional sorbent are highly effective to remove alkalies from the flue gas. Also a mechanism for alkali and lead sorption was proposed. The main topics for 1995 were scheduled to be the completion of the kinetic and mechanical studies and the modelling and the estimation of the data for the pilot scale unit. The kinetic data for one sorbent has been completed and a model for that has also been developed. The measured and calculated results are indicating that the developed multifunctional sorption process is highly effective to remove alkalies and heavy metals such as lead and cadmium from high-temperature combustion gases. The tests are carried out mainly using the pressurized entrained flow reactor of VTT Energy, located in Jyvaeskylae, and in the university of Arizona, where the tests are conducted under atmospheric pressure. Some comparisons of the results might be made with those of Aabo Akademi during the future modelling. 3. The results are applied to purification of the hot gases in boilers, power and process industry. (Abstract Truncated)

  20. Non-catalytic plasma-arc reforming of natural gas with carbon dioxide as the oxidizing agent for the production of synthesis gas or hydrogen - HTR2008-58023

    International Nuclear Information System (INIS)

    The world's energy consumption is increasing constantly due to the growing population of the world. The increasing energy consumption has a negative effect on the fossil fuel reserves of the world. Hydrogen has the potential to provide energy for all our needs by making use of fossil fuel such as natural gas and nuclear-based electricity. Hydrogen can be produced by reforming methane with carbon dioxide as the oxidizing agent. Hydrogen can be produced in a Plasma-arc reforming unit making use of the heat energy generated by a 500 MWt Pebble Bed Modular Reactor (PBMR). The reaction in the unit takes place stoichiometrically in the absence of a catalyst. Steam can be added to the feed stream together with the Carbon Dioxide, which make it possible to control the H2/CO ratio in the synthesis gas between 1/1 and 3/1. This ratio of H2/CO in the synthesis gas is suitable to be used as feed gas to almost any chemical and petrochemical process. To increase the hydrogen production further, the Water-Gas Shift Reaction can be applied. A techno-economic analysis was performed on the non-catalytic plasma-arc reforming process. The capital cost of the plant is estimated at $463 million for the production of 1 132 million Nm3/year of hydrogen. The production cost of hydrogen is in the order of $12.81 per GJ depending on the natural gas cost and the price of electricity. (authors)

  1. Gas Phase Selective Catalytic Oxidation of Toluene to Benzaldehyde on V2O5-Ag2O/η-Al2O3 Catalyst

    Institute of Scientific and Technical Information of China (English)

    Tonglai Zhang; Liqiu Mao; Weihua Liu

    2004-01-01

    Gas phase selective catalytic oxidation of toluene to benzaldehyde was studied on V2O5-Ag2O/η-Al2O3 catalyst prepared by impregnation. The catalyst was characterized by XRD, XPS, TEM,and FT-IR. The catalytic results showed that toluene conversion and selectivity for benzaldehyde on catalyst sample No.4 (V/(V+Ag)=0.68) was higher than other catalysts with different V/Ag ratios. This was attributed to the higher surface area, larger pore volume and pore diameter of the catalyst sample No.4 than the other catalysts. The XRD patterns recorded from the catalyst before and after the oxidation reaction revealed that the new phases were developed, and this suggested that silver had entered the vanadium lattice. XPS results showed that the vanadium on the surface of No.4 and No.5 sample was more than that in the bulk, thus forming a vanadium rich layer on the surface. It was noted that when the catalyst was doped by potassium promoter, the toluene conversion and selectivity for benzaldehyde were higher than those on the undoped catalyst. This was attributed to the disordered structure of V2O5 lattice of the K-doped catalyst and a better interfacial contact between the particles.

  2. Hot Money, Hot Potato

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    International hot money flowing into Chinese capital markets has caught the attention of Chinese watchdogs The Chinese are not the only ones feasting on the thriving property and stock markets. Apparently, these markets are the targets of international h

  3. Gas chromatographic-mass spectrometric characterization of all acyclic C5-C7 alkenes from fluid catalytic cracked gasoline using polydimethylsiloxane and squalane stationary phases.

    Science.gov (United States)

    Soják, Ladislav; Addová, Gabriela; Kubinec, Róbert; Kraus, Angelika; Hu, Gengyuan

    2002-02-15

    Published retention indices of acyclic alkenes C5-C7 on squalane and polydimethylsiloxane as stationary phases were investigated, and reliable retention indices of alkenes from various sources were converted to separation systems used in a laboratory. Retention indices measured on available authentic commercial alkenes and on alkenic fraction of gasoline, published retention indices as well as means of GC-MS were used for verification of calculated retention indices. Retention of some gas chromatographic unseparated isomer pairs was obtained by mass spectrometric deconvolution using a specific single-ion monitoring. On the basis of these retention data, C5-C7 alkenes were identified and analyzed in the gasoline from fluid catalytic cracking. In the gasoline all 59 acyclic C5-C7 isomeric alkenes were determined at significantly different concentration levels.

  4. Catalytic and Noncatalytic Conversion of Methane to Olefins and Synthesis Gas in an AC Parallel Plate Discharge Reactor

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Khodagholi

    2013-01-01

    Full Text Available Direct conversion of methane to ethylene, acetylene, and synthesis gas at ambient pressure and temperature in a parallel plate discharge reactor was investigated. The experiments were carried out using a quartz reactor of outer diameter of 9 millimeter and a driving force of ac current of 50 Hz. The input power to the reactor to establish a stable gas discharge varied from 9.6 to maximum 15.3 watts (w. The effects of ZSM5, Fe–ZSM5, and Ni–ZSM5 catalysts combined with corona discharge for conversion of methane to more valued products have been addressed. It was found that in presence or absence of a catalyst in gas discharge reactor, the rate of methane and oxygen conversion increased upon higher input power supplied to the reactor. The effect of Fe–ZSM5 catalyst combined with gas discharge plasma yields C2 hydrocarbons up to 21.9%, which is the highest productions of C2 hydrocarbons in this work. The effect of combined Ni–ZSM5 and gas discharge plasma was mainly production of synthesis gas. The advantage of introducing ZSM5 to the plasma zone was increase in synthesis gas and acetylene production. The highest energy efficiency was 0.22 mmol/kJ, which belongs to lower rate of energy injection to the reactor.

  5. Inorganic-organic phase arrangement as a factor affecting gas-phase desulfurization on catalytic carbonaceous adsorbents.

    Science.gov (United States)

    Ansari, Adil; Bandosz, Teresa J

    2005-08-15

    Dried sewage sludge was physically mixed with waste paper (paper-to-sludge ratios from 25% to 75%). To increase the catalytic activity, from 1% to 6% calcium hydroxide was added to the mixtures. Then the precursors were carbonized at 950 degrees C. The performance of materials as H2S adsorbents was tested using a home-developed dynamic breakthrough test. The samples, before and after the adsorption process, were characterized by adsorption of nitrogen, potentiometric titration, thermal analysis, XRF, and SEM. Differences in the performance were linked to the surface properties. Itwas found that mixing paper with sludge increases the amount of H2S adsorbed/oxidized in comparison with that adsorbed/oxidized by the adsorbents obtained from pure precursors (sludge or waste paper) and the capacity is comparable to those of the best activated carbons existing on the market. Although both sewage sludge and waste paper provide the catalytic centers for hydrogen sulfide oxidation, the dispersion of the catalyst and its location within accessible pores is an important factor. The presence of cellulose in the precursor mixture leads to the formation of a light macroporous char whose particles physically separate the inorganic catalytic phase of the sewage sludge origin, decreasing the density of the adsorbent and thus providing more space for storage of oxidation products. This, along with calcium, contributes to a significant increase in the capacity of the materials as hydrogen sulfide adsorbents. On their surface about 30 wt % H2S can be adsorbed, mainly as elemental sulfur or sulfates. The results demonstrate the importance of the composition and arrangement of inorganic/ organic phases for the removal of hydrogen sulfide. The interesting finding is that although some microporosity is necessary to increase the storage area for oxidation products, the carbonaceous phase does not need to be highly microporous. It is important that it provides space for deposition of sulfur

  6. Criteria for selection of dolomites and catalysts for tar elimination from biomass gasification gas. Kinetic constants

    Energy Technology Data Exchange (ETDEWEB)

    Corella, J.; Narvaez, I.; Orio, A. [Madrid Univ. (Spain). Dept. of Chem. Eng.

    1996-12-31

    Calcined dolomites and commercial steam reforming catalysts are used downstream biomass gasifiers for hot catalytic raw gas cleaning. To further compare these solids under a rigorous basis, a reaction network and a kinetic model are presented. The apparent kinetic constant for the tar reduction is here proposed as a basis of comparison. Tar sampling and analysis, and the units used for the space-time in the catalytic reactor affect the kinetic constants observed. (author) (2 refs.)

  7. Local ISM 3D distribution and soft X-ray background: Inferences on nearby hot gas and the North Polar Spur

    CERN Document Server

    Puspitarini, L; Vergely, J L; Snowden, S L

    2014-01-01

    3D maps of the ISM can be used to locate not only IS clouds, but also IS bubbles between the clouds that are blown by stellar winds and supernovae. We compare our 3D maps of the IS dust to the ROSAT diffuse X-ray background maps. In the Plane, there is a good correspondence between the locations and extents of the mapped nearby cavities and the 0.25 keV background emission distribution, showing that most of these nearby cavities contribute to this soft X-ray emission. Assuming a constant dust to gas ratio and homogeneous 1MK hot gas filling the cavities, we modeled in a simple way the 0.25 keV surface brightness along the Galactic plane as seen from the Sun, taking into account the absorption by the mapped clouds. The data-model comparison favors the existence of hot gas in the Local Bubble (LB). The average mean pressure in the local cavities is found to be on the order of about 10,000 cm-3K, in agreement with previous studies. The model overestimates the emission from the huge cavities in the 3rd quadrant. ...

  8. JUPITER WILL BECOME A HOT JUPITER: CONSEQUENCES OF POST-MAIN-SEQUENCE STELLAR EVOLUTION ON GAS GIANT PLANETS

    International Nuclear Information System (INIS)

    When the Sun ascends the red giant branch (RGB), its luminosity will increase and all the planets will receive much greater irradiation than they do now. Jupiter, in particular, might end up more highly irradiated than the hot Neptune GJ 436b and, hence, could appropriately be termed a 'hot Jupiter'. When their stars go through the RGB or asymptotic giant branch stages, many of the currently known Jupiter-mass planets in several-AU orbits will receive levels of irradiation comparable to the hot Jupiters, which will transiently increase their atmospheric temperatures to ∼1000 K or more. Furthermore, massive planets around post-main-sequence stars could accrete a non-negligible amount of material from the enhanced stellar winds, thereby significantly altering their atmospheric chemistry as well as causing a significant accretion luminosity during the epochs of most intense stellar mass loss. Future generations of infrared observatories might be able to probe the thermal and chemical structure of such hot Jupiters' atmospheres. Finally, we argue that, unlike their main-sequence analogs (whose zonal winds are thought to be organized in only a few broad, planetary-scale jets), red-giant hot Jupiters should have multiple, narrow jets of zonal winds and efficient day-night redistribution.

  9. Catalytic and Noncatalytic Conversion of Methane to Olefins and Synthesis Gas in an AC Parallel Plate Discharge Reactor

    OpenAIRE

    Mohammad Ali Khodagholi; Mohammad Irani

    2013-01-01

    Direct conversion of methane to ethylene, acetylene, and synthesis gas at ambient pressure and temperature in a parallel plate discharge reactor was investigated. The experiments were carried out using a quartz reactor of outer diameter of 9 millimeter and a driving force of ac current of 50 Hz. The input power to the reactor to establish a stable gas discharge varied from 9.6 to maximum 15.3 watts (w). The effects of ZSM5, Fe–ZSM5, and Ni–ZSM5 catalysts combined with corona discharge for co...

  10. Integration of Methane Steam Reforming and Water Gas Shift Reaction in a Pd/Au/Pd-Based Catalytic Membrane Reactor for Process Intensification.

    Science.gov (United States)

    Castro-Dominguez, Bernardo; Mardilovich, Ivan P; Ma, Liang-Chih; Ma, Rui; Dixon, Anthony G; Kazantzis, Nikolaos K; Ma, Yi Hua

    2016-09-19

    Palladium-based catalytic membrane reactors (CMRs) effectively remove H₂ to induce higher conversions in methane steam reforming (MSR) and water-gas-shift reactions (WGS). Within such a context, this work evaluates the technical performance of a novel CMR, which utilizes two catalysts in series, rather than one. In the process system under consideration, the first catalyst, confined within the shell side of the reactor, reforms methane with water yielding H₂, CO and CO₂. After reforming is completed, a second catalyst, positioned in series, reacts with CO and water through the WGS reaction yielding pure H₂O, CO₂ and H₂. A tubular composite asymmetric Pd/Au/Pd membrane is situated throughout the reactor to continuously remove the produced H₂ and induce higher methane and CO conversions while yielding ultrapure H₂ and compressed CO₂ ready for dehydration. Experimental results involving (i) a conventional packed bed reactor packed (PBR) for MSR, (ii) a PBR with five layers of two catalysts in series and (iii) a CMR with two layers of two catalysts in series are comparatively assessed and thoroughly characterized. Furthermore, a comprehensive 2D computational fluid dynamics (CFD) model was developed to explore further the features of the proposed configuration. The reaction was studied at different process intensification-relevant conditions, such as space velocities, temperatures, pressures and initial feed gas composition. Finally, it is demonstrated that the above CMR module, which was operated for 600 h, displays quite high H₂ permeance and purity, high CH₄ conversion levels and reduced CO yields.

  11. Integration of Methane Steam Reforming and Water Gas Shift Reaction in a Pd/Au/Pd-Based Catalytic Membrane Reactor for Process Intensification.

    Science.gov (United States)

    Castro-Dominguez, Bernardo; Mardilovich, Ivan P; Ma, Liang-Chih; Ma, Rui; Dixon, Anthony G; Kazantzis, Nikolaos K; Ma, Yi Hua

    2016-01-01

    Palladium-based catalytic membrane reactors (CMRs) effectively remove H₂ to induce higher conversions in methane steam reforming (MSR) and water-gas-shift reactions (WGS). Within such a context, this work evaluates the technical performance of a novel CMR, which utilizes two catalysts in series, rather than one. In the process system under consideration, the first catalyst, confined within the shell side of the reactor, reforms methane with water yielding H₂, CO and CO₂. After reforming is completed, a second catalyst, positioned in series, reacts with CO and water through the WGS reaction yielding pure H₂O, CO₂ and H₂. A tubular composite asymmetric Pd/Au/Pd membrane is situated throughout the reactor to continuously remove the produced H₂ and induce higher methane and CO conversions while yielding ultrapure H₂ and compressed CO₂ ready for dehydration. Experimental results involving (i) a conventional packed bed reactor packed (PBR) for MSR, (ii) a PBR with five layers of two catalysts in series and (iii) a CMR with two layers of two catalysts in series are comparatively assessed and thoroughly characterized. Furthermore, a comprehensive 2D computational fluid dynamics (CFD) model was developed to explore further the features of the proposed configuration. The reaction was studied at different process intensification-relevant conditions, such as space velocities, temperatures, pressures and initial feed gas composition. Finally, it is demonstrated that the above CMR module, which was operated for 600 h, displays quite high H₂ permeance and purity, high CH₄ conversion levels and reduced CO yields. PMID:27657143

  12. Advanced anticorrosive coatings prepared from electroactive polyimide/graphene nanocomposites with synergistic effects of redox catalytic capability and gas barrier properties

    Directory of Open Access Journals (Sweden)

    J. M. Yeh

    2014-04-01

    Full Text Available In this study, electroactive polyimide (EPI/graphene nanocomposite (EPGN coatings were prepared by thermal imidization and then characterized by Fourier transformation infrared (FTIR and transmission electron microscope (TEM. The redox behavior of the as-prepared EPGN materials was identified by in situ monitoring for cyclic voltammetry (CV studies. Demonstrating that EPGN coatings provided advanced corrosion protection of cold-rolled steel (CRS electrodes as compared to that of neat EPI coating. The superior corrosion protection of EPGN coatings over EPI coatings on CRS electrodes could be explained by the following two reasons. First, the redox catalytic capabilities of amino-capped aniline trimer (ACAT units existing in the EPGN may induce the formation of passive metal oxide layers on the CRS electrode, as indicated by scanning electron microscope (SEM and electron spectroscopy for chemical analysis (ESCA studies. Moreover, the well-dispersed carboxyl-graphene nanosheets embedded in the EPGN matrix hinder gas migration exponentially. This would explain enhanced oxygen barrier properties of EPGN, as indicated by gas permeability analysis (GPA studies.

  13. Development and characterization of Textron continuous fiber ceramic composite hot gas filter materials. Final report, September 30, 1994--October 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    DiPietro, S.G.; Alvin, M.A.

    1997-12-31

    Uncertainties about the long-term ability of monolithic ceramics to survive in the IGCC or PFBC hot gas filter environment led DOE/METC to consider the merits of using continuous fiber reinforced ceramic composites (CFCCs) as potential next-generation high temperature filter elements. This seems to be a logical strategy to pursue in light of the fact that properly-engineered CFCC materials have shown much-improved damage tolerance and thermal shock behavior as compared to existing monolithic ceramic materials. Textron`s Advanced Hot Gas Filter Development Program was intended to be a two year, two phase program which transitioned developmental materials R and D into prototype filter element fabrication. The first phase was to demonstrate the technical feasibility of fabricating CFCC hot gas filter elements which could meet the pressure drop specifications of less than ten inches of water (iwg) at a face velocity of ten feet per minute (fpm), while showing sufficient integrity to survive normal mechanical loads and adequate environmental resistance to steam/alkali corrosion conditions at a temperature of approximately 870 C (1600 F). The primary objective of the second phase of the program was to scale up fabrication methods developed in Phase 1 to produce full-scale CFCC candle filters for validation testing. Textron encountered significant process-related and technical difficulties in merely meeting the program permeability specifications, and much effort was expended in showing that this could indeed be achieved. Thus, by the time the Phase 1 program was completed, expenditure of program funds precluded continuing on with Phase 2, and Textron elected to terminate their program after Phase 1. This allowed Textron to be able to focus technical and commercialization efforts on their largely successful DOE CFCC Program.

  14. Amperometric NOx-sensor for Combustion Exhaust Gas Control. Studies on transport properties and catalytic activity of oxygen permeable ceramic membranes

    International Nuclear Information System (INIS)

    The aim of the research described in this thesis is the development of a mixed conducting oxide layer, which can be used as an oxygen permselective membrane in an amperometric NOx sensor. The sensor will be used in exhaust gas systems. The exhaust gas-producing engine will run in the lean mix mode. The preparation of this sensor is carried out using screen-printing technology, in which the different layers of the sensor are applied successively. Hereafter, a co-firing step is applied in which all layers are sintered together. This co-firing step imposes several demands on the selection of materials. The design specifications of the sensor further include requirements concerning the operating temperature, measurement range and overall stability. The operating temperature of the sensor varies between 700 and 850C, enabling measurement of NOx concentrations between 50 and 1200 ppm with a measurement accuracy of 10 ppm. Concerning the stability of the sensor, it must withstand the exhaust gas atmosphere containing, amongst others, smoke, acids, abrasive particles and sulphur. Because of the chosen lean-mix engine concept, in which the fuel/air mixture switches continuously between lean (excess oxygen) and fat (excess fuel) mixtures, the sensor must withstand alternately oxidising and reducing atmospheres. Besides, it should be resistant to thermal shock and show no cross-sensitivity of NOx with other exhaust gas constituents like oxygen and hydrocarbons. The response time should be short, typically less than 500 ms. Because of the application in combustion engines of cars, the operational lifetime should be longer than 10 years. Demands on the mixed conducting oxide layer include the following ones. The layer should show minimal catalytic activity towards NOx-reduction. The oxygen permeability must be larger than 6.22 10-8 mol/cm2s at a layer thickness between 3-50 μm. Since the mixed conducting oxide layer is coated on the YSZ electrolyte embodiment, the two

  15. Silver-mordenite for radiologic gas capture from complex streams. Dual catalytic CH3I decomposition and I confinement

    International Nuclear Information System (INIS)

    The selective capture of radiological iodine (129I) is a persistent concern for safe nuclear energy. In these nuclear fuel reprocessing scenarios, the gas streams to be treated are extremely complex, containing several distinct iodine-containing molecules amongst a large variety of other species. Silver-containing mordenite (MOR) is a longstanding benchmark for radioiodine capture, reacting with molecular iodine (I2) to form AgI. However the mechanisms for organoiodine capture is not well understood. Here we investigate the capture of methyl iodide from complex mixed gas streams by combining chemical analysis of the effluent gas stream with in depth characterization of the recovered sorbent. Tools applied include infrared spectroscopy, thermogravimetric analysis with mass spectrometry, micro X-ray fluorescence, powder X-ray diffraction analysis, and pair distribution function analysis. Moreover, the MOR zeolite catalyzes decomposition of the methyl iodide through formation of surface methoxy species (SMS), which subsequently reacts with water in the mixed gas stream to form methanol, and with methanol to form dimethyl ether, which are both detected downstream in the effluent. The liberated iodine reacts with Ag in the MOR pore to the form subnanometer AgI clusters, smaller than the MOR pores, suggesting that the iodine is both physically and chemically confined within the zeolite

  16. Comparison of the enhanced gas sensing properties of tin dioxide samples doped with different catalytic transition elements.

    Science.gov (United States)

    Yang, Fuchao; Guo, Zhiguang

    2015-06-15

    In this work, non-doped SnO2 samples, and SnO2 samples doped with Zn(II), Cu(II), or Mn(II), having hierarchical microstructures, were prepared using an otherwise identical hydrothermal process, followed by annealing. The morphological and structural characteristics of the samples were systematically characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) measurements, and X-ray photoelectron spectroscopy (XPS). Ten gas sensors were constructed from each material, and compared as to detection of gas-phase ethanol, acetone, glacial acetic acid, methanol, and ammonia. The results indicated, for example, that SnO2 containing 2.91% Mn dopant exhibited a 2.5-fold higher gas detection response toward ethanol at 100 ppm than that of the non-doped material. The fastest response time for 100 ppm ethanol was found for Cu(II)-doped SnO2 (9.7 s), compared with 12.4 s for non-doped SnO2. Graphs of sensor response versus operating temperature for SnO2 containing different types and quantities of dopant exhibited quite different morphologies. The gas-sensing mechanism appears to involve reactions between the detected gases and the various oxygenous ions, such as O, O2(-), and O(2-), present at the surface of the sensor.

  17. Experimental Investigations of the Energy and Environmental Indices of Operation of a Low-Capacity Combined Gas Producer and Hot-Water Boiler

    Science.gov (United States)

    Bodnar, L. A.; Stepanov, D. V.; Dovgal‧, A. N.

    2015-07-01

    It has been shown that the introduction of combined gas producers and boilers on renewable energy sources is a pressing issue. A structural diagram of a low-capacity combined gas producer and boiler on renewable energy sources has been given; a bench and procedures for investigation and processing of results have been developed. Experimental investigations of the energy and environmental indices of a 40-kW combined gas producer and hotwater boiler burning wood have been carried out. Results of the experimental investigations have been analyzed. Distinctive features have been established and a procedure of thermal calculation of the double furnace of a lowcapacity combined gas producer and boiler burning solid fuel has been proposed. The calculated coefficients of heat transfer from the gases in the convection bank have been compared with the obtained experimental results. A calculation dependence for the heat transfer from the gases in convection banks of low-capacity hot-water boilers has been proposed. The quantities of harmful emissions from the combined gas producer and boiler on renewable energy sources have been compared with the existing Ukrainian and foreign standards. It has been established that the environmental efficiency of the boiler under study complies with most of the standard requirements of European countries.

  18. CFD studies on the phenomena around counter-current flow limitations of gas/liquid two-phase flow in a model of a PWR hot leg

    Energy Technology Data Exchange (ETDEWEB)

    Deendarlianto, E-mail: deendarlianto@ugm.ac.id [Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Safety Research, P.O. Box 510 119, D-01314 Dresden (Germany); Department of Mechanical and Industrial Engineering, Faculty of Engineering, Gadjah Mada University, Jalan Grafika No. 2, Yogyakarta 55281 (Indonesia); Hoehne, Thomas; Lucas, Dirk; Vallee, Christophe [Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Safety Research, P.O. Box 510 119, D-01314 Dresden (Germany); Zabala, Gustavo Adolfo Montoya [Department of Chemical Engineering, Simon Bolivar University, Valle of Sartenejas, Caracas 1080 (Venezuela, Bolivarian Republic of)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer We modelled CCFL in a PWR hot leg using Algebraic Interfacial Area Density model. Black-Right-Pointing-Pointer The model is able to distinguish the local flow morphologies. Black-Right-Pointing-Pointer Test fluids are air-water and steam-water. Black-Right-Pointing-Pointer Calculated CCFL and water level are in good agreement with experimental data. - Abstract: In order to improve the understanding of counter-current two-phase flow and to validate new physical models, CFD simulations of a 1/3rd scale model of the hot leg of a German Konvoi pressurized water reactor (PWR) with rectangular cross section were performed. Selected counter-current flow limitation (CCFL) experiments conducted at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) were calculated with ANSYS CFX using the multi-fluid Euler-Euler modelling approach. The transient calculations were carried out using a gas/liquid inhomogeneous multiphase flow model coupled with a shear stress transport (SST) turbulence model. In the simulation, the drag law was approached by a newly developed correlation of the drag coefficient in the Algebraic Interfacial Area Density (AIAD) model. The model can distinguish the bubbles, droplets and the free surface using the local liquid phase volume fraction value. A comparison with the high-speed video observations shows a good qualitative agreement. The results indicate also a quantitative agreement between calculations and experimental data for the CCFL characteristics and the water level inside the hot leg channel.

  19. Au@ZnO nanostructures on porous silicon for photocatalysis and gas-sensing: the effect of plasmonic hot-electrons driven by visible-light

    Science.gov (United States)

    Zhou, Fang; Wang, Qiang; Liu, Wenjun

    2016-08-01

    Nanostructured heterojunctions play key role for transfer and separation of interfacial photo-carriers. At visible light illumination, the effects of Au nanoparticles (NPs) for the photocatalysis and gas-sensing performance of Au@ZnO nanstructures on porous silicon layer are reported. At optimized loading amount of Au NPs, the local surface plasmon resonance (LSPR) effect of Au NPs is studied. Generated by visible light irradiation, the LSPR effect of Au NPs promotes desorption and activation of surface adsorption oxygen species -{{{{O}}}2}-, which is initiated by hot electrons transfer through Au-ZnO nanojunctions. This mechanism is responsible for the enhanced photocatalysis of methyl orange molecular, as well as enhancing the detecting performance for ammonia (NH3) gas at room temperature.

  20. Particulate hot gas stream cleanup technical issues: Task 1.0, Assessment of ash characteristics. Quarterly report, January--March 1995

    Energy Technology Data Exchange (ETDEWEB)

    Pontius, D.H.

    1995-05-01

    Analyses of Hot Gas Stream Cleanup (HGSC) ashes and descriptions of filter performance were made to address the problems with filter operation that are apparently linked to the collected ash. This task is designed to generate data base of the key properties of ashes collected from operating advanced particle filters and to relate these ash proeprties to the operation and performance of these filters. Activities including initial formatting of the data base and entry, modification of the permeability model, and initial design of a high-temperature test device for measuring uncompacted bulk porosity of ashe aggregates (indicator of relative cohesivity of the ash, filter cake porosity/permeability). Chemical analyses of hopper and filter cake ashes from Tidd showed that the consolidation degree could not be accounted for by condensation/adsorption from the flue gas; the mechanism is likely physical rearrangement of the ash particles.

  1. 液压式带压扳孔机在油气井上的应用%Hydraulic Hot -drill Machine Appfications in Oil and Gas Wells

    Institute of Scientific and Technical Information of China (English)

    潘智勇

    2012-01-01

    In the latter part of the production of oil and gas field, oil and gas wells shut down for many years, the gate of production or casing has been rust or welded, it is impossible to open the gate. Use the hydraulic Hot - drill machine to pull the gate to hot - drilling operations, improve construction safety and reduce the labor intensity, and to protect the reservoir, it is important to resume production of wells.%在油气田开发生产中后期,很多长时间关停的油气井长年失修,井口生产、套管等闸门丝杠锈死、闸板脱落或已被盲板焊死,导致无法打开闸门。通过应用液压式带压扳孔机对闸门进行扳孔作业,提高了施工安全性,降低了劳动强度,并保护了油气层,对长停井复产重要的作用。

  2. Enhanced catalytic activity of nanoscale platinum islands loaded onto SnO2 thin film for sensitive LPG gas sensors

    Indian Academy of Sciences (India)

    Divya Haridas; Vinay Gupta; K Sreenivas

    2008-06-01

    In the present study, different catalysts (∼ 10 nm thick) including metals, noble metals and metal oxides, were loaded in dotted island form over SnO2 thin film for LPG gas detection. A comparison of various catalysts indicated that the presence of platinum dotted islands over SnO2 thin film deposited by r.f. sputtering exhibited enhanced response characteristics with a high sensitivity, ∼ 742, at an operating temperature of ∼ 280°C. Different characterization techniques have been employed such as atomic force microscopy, X-ray diffraction and UV–vis spectroscopy, to study the surface morphology, grain size and optical properties of the deposited thin films. The results suggest the possibility of utilizing the sensor element with the present novel method of catalyst dispersal for the efficient detection of LPG.

  3. Catalytic partial oxidation of coke oven gas to syngas in an oxygen permeation membrane reactor combined with NiO/MgO catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhibin; Ding, Weizhong; Zhang, Yunyan; Lu, Xionggang; Zhang, Yuwen; Shen, Peijun [Shanghai Key Laboratory of Modern Metallurgy and Materials Processing, Shanghai University, No. 275 Mail box, 149 Yanchang Road, Shanghai 200072 (China)

    2010-06-15

    A high oxygen permeability and sufficient chemical and mechanical stability mixed ion and electron conductivity membrane to withstand the hash strong oxidation and reduction working conditions is significant for the membrane reactor to commercial-scale plant. In this paper, a disk-shaped Ba{sub 1.0}Co{sub 0.7}Fe{sub 0.2}Nb{sub 0.1}O{sub 3-{delta}} membrane was applied to a membrane reactor for the partial oxidation of methane in coke oven gas (COG) to syngas. The reaction was carried out using NiO/MgO solid solution catalyst by feeding COG. The reforming process was performed successfully; 95% CH{sub 4} conversion, 80% H{sub 2} selectivity, 106% CO selectivity and 16.3 ml cm{sup -2} min{sup -1} oxygen permeation flux were achieved at 1148 K. The reaction has been steadily carried out for more than 100 h. The NiO/MgO catalyst used in the membrane reactor exhibited good catalytic activity and resistance to coking in the COG atmosphere. Characterization of the membrane surface by SEM and XRD after long life test showed that both the surface exposed to the air side and reaction side still preserved the Perovskite structure which is implied that the practical application of this membrane as membrane reactor for partial oxidation of COG is promising. (author)

  4. Integration of Methane Steam Reforming and Water Gas Shift Reaction in a Pd/Au/Pd-Based Catalytic Membrane Reactor for Process Intensification

    Science.gov (United States)

    Castro-Dominguez, Bernardo; Mardilovich, Ivan P.; Ma, Liang-Chih; Ma, Rui; Dixon, Anthony G.; Kazantzis, Nikolaos K.; Ma, Yi Hua

    2016-01-01

    Palladium-based catalytic membrane reactors (CMRs) effectively remove H2 to induce higher conversions in methane steam reforming (MSR) and water-gas-shift reactions (WGS). Within such a context, this work evaluates the technical performance of a novel CMR, which utilizes two catalysts in series, rather than one. In the process system under consideration, the first catalyst, confined within the shell side of the reactor, reforms methane with water yielding H2, CO and CO2. After reforming is completed, a second catalyst, positioned in series, reacts with CO and water through the WGS reaction yielding pure H2O, CO2 and H2. A tubular composite asymmetric Pd/Au/Pd membrane is situated throughout the reactor to continuously remove the produced H2 and induce higher methane and CO conversions while yielding ultrapure H2 and compressed CO2 ready for dehydration. Experimental results involving (i) a conventional packed bed reactor packed (PBR) for MSR, (ii) a PBR with five layers of two catalysts in series and (iii) a CMR with two layers of two catalysts in series are comparatively assessed and thoroughly characterized. Furthermore, a comprehensive 2D computational fluid dynamics (CFD) model was developed to explore further the features of the proposed configuration. The reaction was studied at different process intensification-relevant conditions, such as space velocities, temperatures, pressures and initial feed gas composition. Finally, it is demonstrated that the above CMR module, which was operated for 600 h, displays quite high H2 permeance and purity, high CH4 conversion levels and reduced CO yields. PMID:27657143

  5. Silver-Mordenite for Radiologic Gas Capture from Complex Streams: Dual Catalytic CH3I Decomposition and I Confinement

    Energy Technology Data Exchange (ETDEWEB)

    Tina M. Nenoff; Mark Rodriguez; Nick Soelberg; Karena W. Chapman

    2014-12-01

    The effective capture and storage of radiological iodine (129I) remains a strong concern for safe nuclear waste storage and safe nuclear energy. Silver-containing mordenite (MOR) is a longstanding benchmark for iodine capture. In nuclear fuel reprocessing scenarios, complex gas streams will be present and the need for high selectivity of all iodine containing compounds is of the utmost importance for safety and the environment. In particular, a molecular level understanding of the sorption of organic iodine compounds is not well understood. Here we probe the structure and distribution of methyl iodide sorbed by silver-containing MOR using a combination of crystallographic and materials characterization techniques including: infrared spectroscopy, thermogravimetric analysis with mass spectrometry, Micro-X-ray Fluorescence, powder X-ray diffraction analysis, and pair distribution function analysis. The iodine is captured inside the MOR pore in the form of AgI nanoparticles, that is consistent with the pores sizes of the MOR, indicating that the molecule is both physically and chemically captured in the Ag-MOR. The organic component is surface catalyzed by the zeolite via the formation of Surface Methoxy Species (SMS) that result in downstream organics of dimethyl ether and methanol formation.

  6. Catalytic synthesis of ZnO nanorods on patterned silicon wafer—An optimum material for gas sensor

    Indian Academy of Sciences (India)

    S K Panda; C Jacob

    2009-10-01

    ZnO nanorods have been synthesized over etch-patterned Si (110) wafer using annealed silver thin film as growth catalyst. The growth of ZnO nanorods were performed by a two-step process. Initially, the deposition of Zn thin film was done on the annealed silver catalyst film over etch-patterned Si (110) substrate by thermal evaporation, and then annealed at 800°C in air. The etching of the patterned Si (110) wafers was carried out by 50% aqueous KOH solution. The samples were investigated by optical microscopy, scanning electron microscopy, X-ray diffraction, Raman spectroscopy and room temperature photoluminescence spectroscopy. `V’ shaped grooves with no undercut were formed after etching due to the anisotropic nature of the KOH etchant. The etch-patterned wafer was used to provide larger surface area for ZnO growth by forming `V’-grooves. This ZnO film may be predicted as a very good material for gas sensor.

  7. A nucleation and growth model of vertically-oriented carbon nanofibers or nanotubes by plasma-enhanced catalytic chemical vapor deposition.

    Science.gov (United States)

    Cojocaru, C S; Senger, A; Le Normand, F

    2006-05-01

    Carbon nanofibers are grown by direct current and hot filaments-activated catalytic chemical vapor deposition while varying the power of the hot filaments. Observations of these carbon nanofibers vertically oriented on a SiO2 (8 nm thick)/Si(100) substrate covered with Co nanoparticles (10-15 nm particle size) by Scanning Electron and Transmission Electron Microscopies show the presence of a graphitic "nest" either on the surface of the substrate or at the end of the specific nanofiber that does not encapsulate the catalytic particle. Strictly in our conditions, the activation by hot filaments is required to grow nanofibers with a C2H2 - H2 gas mixture, as large amounts of amorphous carbon cover the surface of the substrate without using hot filaments. From these observations as well as data of the literature, it is proposed that the nucleation of carbon nanofibers occurs through a complex process involving several steps: carbon concentration gradient starting from the catalytic carbon decomposition and diffusion from the surface of the catalytic nanoparticles exposed to the activated gas and promoted by energetic ionic species of the gas phase; subsequent graphitic condensation of a "nest" at the interface of the Co particle and substrate. The large concentration of highly reactive hydrogen radicals mainly provided by activation with hot filaments precludes further spreading out of this interfacial carbon nest over the entire surface of the substrate and thus selectively orientates the growth towards the condensation of graphene over facets that are perpendicular to the surface. Carbon nanofibers can then be grown within the well-known Vapor-Liquid-Solid process. Thus the effect of energetic ions and highly reactive neutrals like atomic hydrogen in the preferential etching of carbon on the edge of graphene shells and on the broadening of the carbon nanofiber is underlined.

  8. Tree Coring as a Complement to Soil Gas Screening to Locate PCE and TCE Source Zones and Hot Spots

    DEFF Research Database (Denmark)

    Nielsen, Mette Algreen; Trapp, Stefan; Rehne Jensen, Pernille;

    2015-01-01

    Preliminary risk assessment for prioritisation of site investigations requires efficient screening to reveal type and level of contamination. The screening methods, tree coring and soil gas sampling were applied and compared at two forested sites contaminated with tetrachloroethylene (PCE...

  9. Summary and assessment of METC zinc ferrite hot coal gas desulfurization test program, final report: Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Underkoffler, V.S.

    1986-12-01

    The Morgantown Energy Technology Center (METC) has conducted a test program to develop a zinc ferrite-based high temperature desulfurization process which could be applied to fuel gas entering downstream components such as molten carbonate fuel cells or gas turbines. As a result of prior METC work with iron oxide and zinc oxide sorbents, zinc ferrite evolved as a candidate with the potential for high capacity, low equilibrium levels of H/sub 2/S, and structural stability after multiple regenerations. The program consisted of laboratory-scale testing with a two-inch diameter reactor and simulated fixed-bed gasifier gas; bench-scale testing with a six-inch diameter reactor and actual gas from the METC 42-inch fixed bed gasifier; as well as laboratory-scale testing of zinc ferrite with simulated fluidized bed gasifier gas. Optimum operating parameters for zinc ferrite such as temperatures, gas compositions, and space velocities are discussed. From the test results, salient features of zinc ferrite were derived and discussed in regard to system implications, issues raised, and technical requirements. 47 refs., 53 figs., 41 tabs.

  10. Catalytic thermal barrier coatings

    Science.gov (United States)

    Kulkarni, Anand A.; Campbell, Christian X.; Subramanian, Ramesh

    2009-06-02

    A catalyst element (30) for high temperature applications such as a gas turbine engine. The catalyst element includes a metal substrate such as a tube (32) having a layer of ceramic thermal barrier coating material (34) disposed on the substrate for thermally insulating the metal substrate from a high temperature fuel/air mixture. The ceramic thermal barrier coating material is formed of a crystal structure populated with base elements but with selected sites of the crystal structure being populated by substitute ions selected to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a higher rate than would the base compound without the ionic substitutions. Precious metal crystallites may be disposed within the crystal structure to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a lower light-off temperature than would the ceramic thermal barrier coating material without the precious metal crystallites.

  11. Effect of hot isostatic pressing on the structure and properties of cast polycrystalline gas-turbine blades made of nickel superalloys

    Science.gov (United States)

    Beresnev, A. G.

    2012-05-01

    A concept of a two-stage hot isostatic pressing (HIP) cycle is developed for castings made of nickel superalloys in order to minimize plastic deformation and the recrystallization ability of their structure. At the first stage of the cycle, diffusion pore dissolution is predominant due to the motion of vacancies toward grain boundaries in a polycrystal; at the second stage, retained coarse pores are filled during plastic deformation. The effect of uniform compression pressure during HIP and microstructure defects on the vacancy diffusion in nickel superalloys is estimated. A two-stage HIP regime is developed for processing of cast gas-turbine engine blades made of a ZhS6U alloy in order to substantially decrease the shrinkage porosity and to increase the high-temperature characteristics, including the creep and fatigue resistance.

  12. 热煤气中碱金属蒸气的脱除%Removal of Alkali Metal Vapor from Hot Coal Gas

    Institute of Scientific and Technical Information of China (English)

    申文琴; 豆彬林; 邢嵘; 沙兴中

    2000-01-01

    Seven adsorbents were screened for removal of alkali metal vapor from hot coal gas. It is found that five adsorbents present higher adsorption efficiency and activated almmina shows the highest adsorption capacity. The adsorption process of activated alumina is a physical process in experimental condition.%为了清除煤燃烧或气化产生的热气体中的碱金属蒸气,筛选了7种吸附剂,发现5种吸附剂的吸附效率都能达到80%以上,其中活性氧化铝的碱容量最高,对活性氧化铝吸附机理也进行了初步探讨。

  13. Search for Solar Axions by the CERN Axion Solar Telescope with 3 He Buffer Gas: Closing the Hot Dark Matter Gap

    CERN Document Server

    Arik, M; Barth, K.; Belov, A.; Borghi, S.; Brauninger, H.; Cantatore, G.; Carmona, J.M.; Cetin, S.A.; Collar, J.I.; Da Riva, E.; Dafni, T.; Davenport, M.; Eleftheriadis, C.; Elias, N.; Fanourakis, G.; Ferrer-Ribas, E.; Friedrich, P.; Galan, J.; Garcia, J.A.; Gardikiotis, A.; Garza, J.G.; Gazis, E.N.; Geralis, T.; Georgiopoulou, E.; Giomataris, I.; Gninenko, S.; Gomez, H.; Gomez Marzoa, M.; Gruber, E.; Guthorl, T.; Hartmann, R.; Hauf, S.; Haug, F.; Hasinoff, M.D.; Hoffmann, D.H.H.; Iguaz, F.J.; Irastorza, I.G.; Jacoby, J.; Jakovcic, K.; Karuza, M.; Konigsmann, K.; Kotthaus, R.; Krcmar, M.; Kuster, M.; Lakic, B.; Lang, P.M.; Laurent, J.M.; Liolios, A.; Ljubicic, A.; Lozza, V.; Luzon, G.; Neff, S.; Niinikoski, T.; Nordt, A.; Papaevangelou, T.; Pivovaroff, M.J.; Raffelt, G.; Riege, H.; Rodriguez, A.; Rosu, M.; Ruz, J.; Savvidis, I.; Shilon, I.; Silva, P.S.; Solanki, S.K.; Stewart, L.; Tomas, A.; Tsagri, M.; van Bibber, K.; Vafeiadis, T.; Villar, J.; Vogel, J.K.; Yildiz, S.C.; Zioutas, K.

    2014-01-01

    The CERN Axion Solar Telescope (CAST) has finished its search for solar axions with 3^He buffer gas, covering the search range 0.64 eV < m_a <1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess X-rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g_ag < 3.3 x 10^{-10} GeV^{-1} at 95% CL, with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of g_a, for example by the currently discussed next generation helioscope IAXO.

  14. Search for solar axions by the CERN axion solar telescope with 3He buffer gas: closing the hot dark matter gap.

    Science.gov (United States)

    Arik, M; Aune, S; Barth, K; Belov, A; Borghi, S; Bräuninger, H; Cantatore, G; Carmona, J M; Cetin, S A; Collar, J I; Da Riva, E; Dafni, T; Davenport, M; Eleftheriadis, C; Elias, N; Fanourakis, G; Ferrer-Ribas, E; Friedrich, P; Galán, J; García, J A; Gardikiotis, A; Garza, J G; Gazis, E N; Geralis, T; Georgiopoulou, E; Giomataris, I; Gninenko, S; Gómez, H; Gómez Marzoa, M; Gruber, E; Guthörl, T; Hartmann, R; Hauf, S; Haug, F; Hasinoff, M D; Hoffmann, D H H; Iguaz, F J; Irastorza, I G; Jacoby, J; Jakovčić, K; Karuza, M; Königsmann, K; Kotthaus, R; Krčmar, M; Kuster, M; Lakić, B; Lang, P M; Laurent, J M; Liolios, A; Ljubičić, A; Luzón, G; Neff, S; Niinikoski, T; Nordt, A; Papaevangelou, T; Pivovaroff, M J; Raffelt, G; Riege, H; Rodríguez, A; Rosu, M; Ruz, J; Savvidis, I; Shilon, I; Silva, P S; Solanki, S K; Stewart, L; Tomás, A; Tsagri, M; van Bibber, K; Vafeiadis, T; Villar, J; Vogel, J K; Yildiz, S C; Zioutas, K

    2014-03-01

    The CERN Axion Solar Telescope has finished its search for solar axions with (3)He buffer gas, covering the search range 0.64 eV ≲ ma ≲ 1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of gaγ ≲ 3.3 × 10(-10)  GeV(-1) at 95% C.L., with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of gaγ, for example by the currently discussed next generation helioscope International AXion Observatory.

  15. Estimating the temperature of a catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Ma, T.T.-H.

    1994-11-02

    A method of estimating the temperature of a catalytic converter used in the exhaust system of an internal combustion engine is described. Heated exhaust gas oxygen (HEGO) sensors are placed upstream and downstream of the catalytic converter. The temperature of the catalytic converter shortly after start-up is measured by monitoring the resistance of the HEGO sensor's heating element. The downstream sensor is used for mixture control and to double check results of the upstream sensor. (UK)

  16. Catalytic Performance and Characterization of Pt-Co/Al2O3Catalysts for CO2 Reforming of CH4 to Synthesis Gas

    Institute of Scientific and Technical Information of China (English)

    HUANG, Chuan-Jing; ZHENG, Xiao-Ming; MO, Liu-Ye; FEI, Jin-Hua

    2001-01-01

    Pt-Co/Al2O3 catalyst has been studied for CO2 reforming of CH4 to synthesis gas. It was found that the catalytic performance of the catalyst was sensitive to calcination temperature.When Co/Al2O3 was calcined at 1473 K prior to adding a small amount of Pt to it, the resulting bimetallic catalyst showed high activity, optimal stability and excellent resistance to carbon deposition, which was more effective to the reaction than Co/Al2O3 and Pt/Al2O3 catalysts. At lower metal loading, catalyst activity decreased in the following order: Pt-Co/Al2O3 > Pt/Al2O3 》 Co/Al2O3. With 9% Co, the Co/Al2O3calcined at 923 K was also active for CO2 reforming of CH4,however, its carbon formation was much more fast than that of the Pt-Co/Al2O3 catalyst. The XRD results indicated that Pt species well dispersed over the bimetallic catalyst. Its high dispersion was related to the presence of CoAl2O4, formed during calcining of Co/Al2O3 at high temperature before Pt addition. Promoted by Pt, CoAl2O4 in the catalyst could be reduced partially even at 923 K, the temperature of pre-re-duction for the reaction, confirmed by TPR. Based on these results, it was considered that the zerovalent platinum with high dispersion over the catalyst surface and the zerovalent cobalt resulting from CoAl2O4 reduction are responsible for high activity of the Pt-Co/Al2O3 catalyst, and the remain CoAl2O4 is beneficial to suppression of carbon deposition over the catalyst.

  17. Development of Fuel Rod Puncturing and Fission Gas Collection System for Post Irradiation Examination in Hot cell

    International Nuclear Information System (INIS)

    After a fuel pin and small fuel rig for R/D were irradiated in a research reactor, a small amount of the fission gas exists into the internal void in a pin and a rig. A steel needle was not useful for these small fuel rods. Alternatively, the laser puncturing technique was developed to solve the measurement of a small amount of fission gas. This system is considered very rare equipment in other countries. A fine pressure gauge and strong vacuum system were installed, and the chamber volume was reduced as small as possible. A fiber laser was used for easy operation. To measure the small fission gas inventory in a fuel rod, a laser puncturing method was introduced. The reliability of the pressure measurement was found to have an error of 1% after a test of four sample bottles with different pressures. In the test of six sample rods, an under estimation was found because of a different pressure gauge was used in the rod preparation. However, there was consistency between the results of some rods. We need to check the properties and mechanical differences of each gauge

  18. The nature and energetics of AGN-driven perturbations in the hot gas in the Perseus Cluster

    CERN Document Server

    Zhuravleva, I; Arevalo, P; Schekochihin, A A; Forman, W R; Allen, S W; Simionescu, A; Sunyaev, R; Vikhlinin, A; Werner, N

    2016-01-01

    Cores of relaxed galaxy clusters are often disturbed by AGN. Their Chandra observations revealed a wealth of structures induced by shocks, subsonic gas motions, bubbles of relativistic plasma, etc. In this paper, we determine the nature and energy content of gas fluctuations in the Perseus core by probing statistical properties of emissivity fluctuations imprinted in the soft- and hard-band X-ray images. About 80 per cent of the total variance of perturbations on ~ 8-70 kpc scales in the inner region have an isobaric nature, i.e., are consistent with slow displacements of the gas in pressure equilibrium with ambient medium. Observed variance translates to the ratio of non-thermal to thermal energy of ~13 per cent. In the region dominated by weak "ripples", about half of the total variance is also associated with isobaric perturbations on scales ~ a few tens of kpc. If these isobaric perturbations are induced by buoyantly rising bubbles, then these results suggest that most of the AGN-injected energy should fi...

  19. Application of catalytic combustion technology in the treatment of foul gas from refinery waste water treatment plant%催化燃烧技术在炼油污水处理场恶臭治理中的应用

    Institute of Scientific and Technical Information of China (English)

    刘永斌; 程俊梅; 程彬彬

    2011-01-01

    介绍了催化燃烧技术在炼油污水处理场恶臭治理中的应用情况.工业应用表明,催化燃烧技术适用于处理石化炼油污水场总进水口、隔油池、浮选池等散发的恶臭气体,废气处理效果良好.恶臭治理设施运行后,对硫化物的去除率达95%以上,对硫化氢的去除率接近100%,对总烃的去除率达到85%以上,净化后的气体能够满足国家排放标准的要求.催化燃烧技术治理恶臭污染项目的实施,对同类型炼化装置将起到借鉴作用.%The application of catalytic combustion technology in the treatment of foul gas from refinery waste water treatment plant was introduced. The catalytic combustion technology was applicable for the treatment of foul gases from water inlet of refinery waste water treatment plant, API separator, flotation pit, etc with good results. After operation of foul gas treatment facilities, the sulfide removal rate is over 95% , the H2S removal rate is close to 100% and total hydrocarbons removal rate is more than 85%. The purified gas meets China national emission standards. The implementation of foul gas treatment facilities using catalytic combustion technology provides a good reference for the operation of similar refinery process units.

  20. Rhapsody-G simulations I: the cool cores, hot gas and stellar content of massive galaxy clusters

    CERN Document Server

    Hahn, Oliver; Wu, Hao-Yi; Evrard, August E; Teyssier, Romain; Wechsler, Risa H

    2015-01-01

    We present the Rhapsody-G suite of cosmological hydrodynamic AMR zoom simulations of ten massive galaxy clusters at the $M_{\\rm vir}\\sim10^{15}\\,{\\rm M}_\\odot$ scale. These simulations include cooling and sub-resolution models for star formation and stellar and supermassive black hole feedback. The sample is selected to capture the whole gamut of assembly histories that produce clusters of similar final mass. We present an overview of the successes and shortcomings of such simulations in reproducing both the stellar properties of galaxies as well as properties of the hot plasma in clusters. In our simulations, a long-lived cool-core/non-cool core dichotomy arises naturally, and the emergence of non-cool cores is related to low angular momentum major mergers. Nevertheless, the cool-core clusters exhibit a low central entropy compared to observations, which cannot be alleviated by thermal AGN feedback. For cluster scaling relations we find that the simulations match well the $M_{500}-Y_{500}$ scaling of Planck ...

  1. Catalytic ethanolysis and gasification of kraft lignin into aromatic alcohols and H2-rich gas over Rh supported on La2O3/CeO2-ZrO2.

    Science.gov (United States)

    Yang, Jing; Zhao, Liang; Liu, Chunze; Wang, Yuanyuan; Dai, Liyi

    2016-10-01

    Efficient catalytic ethanolysis and gasification of kraft lignin were conducted over a versatile supported catalyst Rh/La2O3/CeO2-ZrO2 to give high-value aromatic alcohols and H2-rich gas. The removal of phenolic hydroxyl group was the most prevalent reaction, and importantly, almost no phenols, undesired char and saturating the aromatic ring were detected. Meanwhile, the feedstock and solvent both played key roles in H2 generation that contributed to the hydrodeoxygenation of liquid components and made the whole catalytic process out of H2 supply. Reusability tests of catalyst indicated that the crystalline phase transition and agglomeration of support, the loss of noble metal Rh and carbon deposition were the possible reasons for its deactivation in supercritical ethanol. Comparing with water, methanol and isopropanol system, ethanol was the only effective solvent for the depolymerization process. PMID:27441830

  2. HOT 2012

    DEFF Research Database (Denmark)

    Lund, Henriette Romme

    Undersøgelse af, hvad der er hot - og hvad der burde være hot på læseområdet med 21 læsekyndige. Undersøgelsen er gennemført siden 2010. HOT-undersøgelsen er foretaget af Nationalt Videncenter for Læsning - Professionshøjskolerne i samarb. med Dansklærerforeningen...

  3. The impact of stellar feedback on hot gas in galaxy haloes: the Sunyaev-Zel'dovich effect and soft X-ray emission

    Science.gov (United States)

    van de Voort, Freeke; Quataert, Eliot; Hopkins, Philip F.; Faucher-Giguère, Claude-André; Feldmann, Robert; Kereš, Dušan; Chan, T. K.; Hafen, Zachary H.

    2016-09-01

    The thermal Sunyaev-Zel'dovich (SZ) effect and soft X-ray emission are routinely observed around massive galaxies and in galaxy groups and clusters. We study these observational diagnostics of galaxy haloes for a suite of cosmological `zoom-in' simulations from the `Feedback In Realistic Environments' project, which spans a large range in halo mass (1010 - 13 M⊙). We explore the effect of stellar feedback on the hot gas observables. The properties of our simulated groups, such as baryon fractions, SZ flux, and X-ray luminosities (LX), are broadly consistent with existing observations, even though feedback from active galactic nuclei is not included. We make predictions for future observations of lower-mass objects for both SZ and diffuse X-ray measurements, finding that they are not just scaled-down versions of massive galaxies, but more strongly affected by galactic winds driven by star formation. Low-mass haloes (≲ 1011 M⊙) retain a low fraction of their baryons, which results in a strong suppression of the SZ signal. Our simulations therefore predict a scaling with halo mass that is steeper than self-similar for haloes less massive than 1013 M⊙. For halo masses ≲ 1012 M⊙, LX is time-variable and correlated primarily with the star formation rate (SFR). For these objects, the diffuse X-ray emission is powered mostly by galactic winds and the gas dominating the X-ray emission is flowing out with radial velocities close to the halo's circular velocity. For halo masses ≳ 1013 M⊙, on the other hand, LX is much less variable and not correlated with the SFR, because the emission originates from the quasi-hydrostatic, virialized halo gas.

  4. The nature and energetics of AGN-driven perturbations in the hot gas in the Perseus Cluster

    Science.gov (United States)

    Zhuravleva, I.; Churazov, E.; Arévalo, P.; Schekochihin, A. A.; Forman, W. R.; Allen, S. W.; Simionescu, A.; Sunyaev, R.; Vikhlinin, A.; Werner, N.

    2016-05-01

    Cores of relaxed galaxy clusters are often disturbed by AGN. Their Chandra observations revealed a wealth of structures induced by shocks, subsonic gas motions, bubbles of relativistic plasma, etc. In this paper, we determine the nature and energy content of gas fluctuations in the Perseus core by probing statistical properties of emissivity fluctuations imprinted in the soft- and hard-band X-ray images. About 80 per cent of the total variance of perturbations on ˜8-70 kpc scales in the core have an isobaric nature, i.e. are consistent with subsonic displacements of the gas in pressure equilibrium with the ambient medium. The observed variance translates to the ratio of energy in perturbations to thermal energy of ˜13 per cent. In the region dominated by weak `ripples', about half of the total variance is associated with isobaric perturbations on scales of a few tens of kpc. If these isobaric perturbations are induced by buoyantly rising bubbles, then these results suggest that most of the AGN-injected energy should first go into bubbles rather than into shocks. Using simulations of a shock propagating through the Perseus atmosphere, we found that models reproducing the observed features of a central shock have more than 50 per cent of the AGN-injected energy associated with the bubble enthalpy and only about 20 per cent is carried away with the shock. Such energy partition is consistent with the AGN-feedback model, mediated by bubbles of relativistic plasma, and supports the importance of turbulence in the cooling-heating balance.

  5. Dynamics of Greenhouse Gas Emissions from Riparian Buffer Zones and Wetlands as Hot Spots in Agricultural Landscapes

    International Nuclear Information System (INIS)

    The study considers various aspects of riparian buffer zones and wetlands for greenhouse gas emissions in agricultural landscapes of northern and north-eastern Europe. In particular, the impact of pulsing water regime, continuous loading and several alterations of environmental conditions on greenhouse gas emissions are taken into the consideration. In two case studies the isotopologue technique was used to distinguish between N2O sources in both riparian zones and constructed wetlands. Nitrous oxide (N2O) and nitrogen (N2) emissions, isotopic signatures of N2O and nitrate (NO3-) in groundwater of two differently loaded riparian grey alder stands in southern Estonia were investigated over a period of nine months. One area was a 38-year-old stand in Porijõgi (PJ), where uphill agricultural activities had been abandoned since the middle of 1990s, and the second area was a 55-year-old alder stand in Viiratsi (Vi), which still receives polluted lateral flow from uphill fields applied with pig slurry. Gas fluxes were measured in six sampling sessions, and water samples were analysed for NO3-, N2, N2O, and isotopic signatures of oxygen-18 (delta 18O, δ18O) and nitrogen-15 (delta 15N, δ15N) in N2O and NO3- in four of the six sessions. The N2O and N2 fluxes from both riparian zones did not differ significantly, being 9.6 ± 4.7 and 14.5 ± 3.9 μg N2O–N m−2 h−1, and 2 466 ± 275 and 3 083 ± 371 μg N2–N m−2 h−1 in PJ and Vi sites respectively, suggesting that gaseous N2 is the dominant gas emission from these alder stands. The isotopic signatures of N2O and NO3- were not significantly different between PJ and Vi study sites suggesting possible conversion of NO3- to N2O in both areas. The greater prevalence of N2 emissions over N2O in both areas, and the strong relationship between NO3- and N2O concentrations (r2 = 0.846, with p < 0.01) further suggested that denitrification is the main source of N2O and N2 fluxes in these grey alder stands. The dominant

  6. Abundance Ratios in Stars vs. Hot Gas in Elliptical Galaxies: the Chemical Evolution Modeller Point of View

    CERN Document Server

    Pipino, A

    2009-01-01

    I will present predictions from chemical evolution model aimed at a self-consistent study of both optical (i.e. stellar) and X-ray (i.e.gas) properties of present-day elliptical galaxies. Detailed cooling and heating processes in the interstellar medium (ISM) are taken into and allow a reliable modelling of the SN-driven galactic wind. SNe Ia activity, in fact, may power a galactic wind lasting for a considerable amount of the galactic lifetime, even in the case for which the efficiency of energy transfer into the ISM per SN Ia event is less than unity. The model simultaneously reproduces the mass-metallicity, the colour-magnitude, the L_X - L_B and the L_X - T relations, as well as the observed trend of the [Mg/Fe] ratio as a function of sigma, by adopting the prescriptions of Pipino & Matteucci (2004) for the gas infall and star formation timescales. The "iron discrepancy", namely the too high predicted iron abundance in X-ray haloes of ellipticals compared to observations, can be solved by taking into ...

  7. Violent interaction between the AGN and the hot gas in the core of the galaxy cluster Sersic 159-03

    CERN Document Server

    Werner, N; Bagchi, J; Allen, S W; Taylor, G B; Sirothia, S K; Simionescu, A; Million, E T; Jacob, J; Donahue, M

    2011-01-01

    We present a multi-wavelength study of the energetic interaction between the central active galactic nucleus (AGN), the intra-cluster medium, and the optical emission line nebula in the galaxy cluster Sersic 159-03. We use X-ray data from Chandra, high resolution X-ray spectra and UV images from XMM-Newton, Halpha images from the SOAR telescope, HST optical imaging, and VLA and GMRT radio data. The cluster center displays signs of powerful AGN feedback, which has cleared the central regions (r<7.5 kpc) of dense, X-ray emitting ICM. X-ray spectral maps reveal a high pressure ring surrounding the central AGN at a radius of r~15 kpc, indicating an AGN driven weak shock. The cluster harbors a bright, 44 kpc long Halpha+[NII] filament extending from the centre of the cD galaxy to the north. Along the filament, we see low entropy, high metallicity, cooling X-ray gas. The gas in the filament has most likely been uplifted by `radio mode' AGN activity and subsequently stripped from the galaxy due to its relative so...

  8. Hot Groups.

    Science.gov (United States)

    Vail, Kathleen

    1996-01-01

    Collaborators sparked by creative ideas and obsessed by a common task may not realize they're part of a "hot group"--a term coined by business professors Harold J. Leavitt and Jean Lipman-Blumen. Spawned by group decision making and employee empowerment, hot groups can flourish in education settings. They're typically small, short lived, and goal…

  9. Temperature excursions during the transient behaviour of high temperature catalytic combustion monoliths

    Energy Technology Data Exchange (ETDEWEB)

    Di Benedetto, Almerinda; Cimino, Stefano; Pirone, Raffaele; Russo, Gennaro [Istituto Ricerche sulla Combustione-CNR, P. le Tecchio 80, 80125 Naples (Italy)

    2003-08-15

    Spatio-temporal temperature profiles experimentally observed during the operation of a structured perovskite-based catalytic monolith for the combustion of methane were simulated by means of a transient heterogeneous one-dimensional model which accounts for heat losses to the surroundings and thermal conductivity inside the monolith substrate. In fact it is shown that such thermal phenomena are essential to correctly reproduce the slow warm-up transients and the wrong-way behaviour observed in a low conductivity ceramic monolith. Model simulations reveal that at higher values of solid conductivity the catalyst does not exhibit hot spot both in time and space, but needs higher inlet gas temperatures to reach complete methane conversion. Bifurcation analysis of the catalytic monolith reactor model were carried out to study steady-state multiplicity. We show that the origin of multiplicity is purely thermal as it is mainly ruled by the heat transfer through the external surface.

  10. BEC-BCS Crossover and the Liquid-Gas Phase Transition in Hot and Dense Nuclear Matter

    CERN Document Server

    Jin, Meng; Schuck, Peter

    2010-01-01

    The effect of nucleon-nucleon correlations in symmetric nuclear matter at finite temperature is studied beyond BCS theory. Starting from a Hartree-Fock description of nuclear matter with the Gogny effective interaction, we add correlations corresponding to the formation of preformed pairs and scattering states above the superfluid critical temperature within the in-medium T-matrix approach, which is analogous to the Nozieres-Schmitt-Rink theory. We calculate the critical temperature for a BEC superfluid of deuterons, of a BCS superfluid of nucleons, and in the crossover between these limits. The effect of the correlations on thermodynamic properties (equation of state, energy, entropy) and the liquid-gas phase transition is discussed. Our results show that nucleon-nucleon correlations beyond BCS play an important role for the properties of nuclear matter, especially in the low-density region.

  11. Hydrogen sulfide removal from hot coal gas by various mesoporous silica supported Mn{sub 2}O{sub 3} sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z.F.; Liu, B.S., E-mail: bingsiliu@tju.edu.cn; Wang, F.; Wang, W.S.; Xia, C.; Zheng, S.; Amin, R.

    2014-09-15

    Graphical abstract: - Highlights: • Mn{sub 2}O{sub 3}/KIT-1 presented the best desulfurization performance at 600–850 °C. • High sulfur capacity of Mn{sub 2}O{sub 3}/KIT-1 correlated closely with 3-D channel of KIT-1. • Desulfurization character depended strongly on framework structure of sorbents. • High steam content suppressed greatly the occurrence of sulfidation reaction. - Abstract: A series of 50 wt% Mn{sub 2}O{sub 3} sorbents was prepared using various mesoporous silica, MCM-41, HMS, and KIT-1 as support. The influence of textural parameters of mesoporous silica, especially type of channel on the desulfurization performance of Mn{sub 2}O{sub 3} sorbents was investigated at 600–850 °C using hot coal gas containing 0.33 vol.% H{sub 2}S. The fresh and used sorbents were characterized by means of N{sub 2}-adsorption, x-ray diffraction (XRD), high resolution transmission microscopy (HRTEM) and H{sub 2} temperature- programmed reduction (H{sub 2}-TPR) techniques. The results confirmed that the manganese oxide was dispersed highly in regular pore channel of the mesoporous supports due to high surface area. Compared with the Mn{sub 2}O{sub 3}/diatomite, all mesoporous silica supported Mn{sub 2}O{sub 3} sorbents exhibited high breakthrough sulfur capacity and a sharp deactivation rate after the breakthrough point. Compared to Mn{sub 2}O{sub 3}/MCM-41 and Mn{sub 2}O{sub 3}/HMS sorbent, the Mn{sub 2}O{sub 3}/KIT-1 showed better desulfurization performance because of the 3D wormhole-like channel. The high sulfur capacity of the Mn{sub 2}O{sub 3}/KIT-1 sorbent was maintained during the eight consecutive desulfurization-regeneration cycles. The Mn{sub 2}O{sub 3}/KIT-1 still presented high desulfurization activity when hot coal gas contained low steam (<5%)

  12. Fluid geochemistry and soil gas fluxes (CO2-CH4-H2S) at a promissory Hot Dry Rock Geothermal System: The Acoculco caldera, Mexico

    Science.gov (United States)

    Peiffer, L.; Bernard-Romero, R.; Mazot, A.; Taran, Y. A.; Guevara, M.; Santoyo, E.

    2014-09-01

    The Acoculco caldera has been recognized by the Mexican Federal Electricity Company (CFE) as a Hot Dry Rock Geothermal System (HDR) and could be a potential candidate for developing an Enhanced Geothermal System (EGS). Apart from hydrothermally altered rocks, geothermal manifestations within the Acoculco caldera are scarce. Close to ambient temperature bubbling springs and soil degassing are reported inside the caldera while a few springs discharge warm water on the periphery of the caldera. In this study, we infer the origin of fluids and we characterize for the first time the soil degassing dynamic. Chemical and isotopic (δ18O-δD) analyses of spring waters indicate a meteoric origin and the dissolution of CO2 and H2S gases, while gas chemical and isotopic compositions (N2/He, 3He/4He, 13C, 15N) reveal a magmatic contribution with both MORB- and arc-type signatures which could be explained by an extension regime created by local and regional fault systems. Gas geothermometry results are in agreement with temperature measured during well drilling (260 °C-300 °C). Absence of well-developed water reservoir at depth impedes re-equilibration of gases upon surface. A multi-gas flux survey including CO2, CH4 and H2S measurements was performed within the caldera. Using the graphical statistical analysis (GSA) approach, CO2 flux measurements were classified in two populations. Population A, representing 95% of measured fluxes is characterized by low values (mean: 18 g m- 2 day- 1) while the remaining 5% fluxes belonging to Population B are much higher (mean: 5543 g m- 2 day- 1). This low degassing rate probably reflects the low permeability of the system, a consequence of the intense hydrothermal alteration observed in the upper 800 m of volcanic rocks. An attempt to interpret the origin and transport mechanism of these fluxes is proposed by means of flux ratios as well as by numerical modeling. Measurements with CO2/CH4 and CO2/H2S flux ratios similar to mass ratios

  13. Origin of the hot gas in low-mass protostars: Herschel-PACS spectroscopy of HH 46

    CERN Document Server

    van Kempen, T A; Herczeg, G J; Visser, R; van Dishoeck, E F; Wampfler, S F; Bruderer, S; Benz, A O; Doty, S D; Brinch, C; Hogerheijde, M R; Jørgensen, J K; Tafalla, M; Neufeld, D; Bachiller, R; Baudry, A; Benedettini, M; Bergin, E A; Bjerkeli, P; Blake, G A; Bontemps, S; Braine, J; Caselli, P; Cernicharo, J; Codella, C; Daniel, F; di Giorgio, A M; Dominik, C; Encrenaz, P; Fich, M; Fuente, A; Giannini, T; Goicoechea, J R; de Graauw, Th; Helmich, F; Herpin, F; Jacq, T; Johnstone, D; Kaufman, M J; Larsson, B; Lis, D; Liseau, R; Marseille, M; McCoey, C; Melnick, G; Nisini, B; Olberg, M; Parise, B; Pearson, J C; Plume, R; Risacher, C; Santiago-Garcia, J; Saraceno, P; Shipman, R; van der Tak, F; Wyrowski, F; Yildiz, U A; Ciechanowicz, M; Dubbeldam, L; Glenz, S; Huisman, R; Lin, R H; Morris, P; Murphy, J A; Trappe, N

    2010-01-01

    'Water in Star-forming regions with Herschel' (WISH) is a Herschel Key Programme aimed at understanding the physical and chemical structure of young stellar objects (YSOs) with a focus on water and related species. The low-mass protostar HH 46 was observed with the Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory to measure emission in H2O, CO, OH, [OI], and [CII] lines located between 63 and 186 um. The excitation and spatial distribution of emission can disentangle the different heating mechanisms of YSOs, with better spatial resolution and sensitivity than previously possible. Far-IR line emission is detected at the position of the protostar and along the outflow axis. The OH emission is concentrated at the central position, CO emission is bright at the central position and along the outflow, and H2O emission is concentrated in the outflow. In addition, [OI] emission is seen in low-velocity gas, assumed to be related to the envelope, and is also seen shifted up to 170 km...

  14. Gas Giants in Hot Water: Inhibiting Giant Planet Formation and Planet Habitability in Dense Star Clusters Through Cosmic Time

    CERN Document Server

    Thompson, Todd A

    2012-01-01

    I show that the temperature of nuclear star clusters, starburst clusters in M82, compact high-z galaxies, and some globular clusters of the Galaxy likely exceeded the ice line temperature (T_Ice ~ 150-170 K) during formation for a time comparable to the planet formation timescale. The protoplanetary disks within these systems will thus not have an ice line, decreasing the total material available for building protoplanetary embryos, inhibiting the formation of gas- and ice-giants if they form by core accretion, and prohibiting habitability. Planet formation by gravitational instability is similarly suppressed because Toomre's Q > 1 in all but the most massive disks. I discuss these results in the context of the observed lack of planets in 47 Tuc. I predict that a similar search for planets in the globular cluster NGC 6366 ([Fe/H] = -0.82) should yield detections, whereas (counterintuitively) the relatively metal-rich globular clusters NGC 6440, 6441, and 6388 should be devoid of giant planets. The characteris...

  15. The nearby interstellar medium towards alpha Leo -- UV observations and modeling of a warm cloud within hot gas

    CERN Document Server

    Gry, Cecile

    2016-01-01

    We analyze interstellar absorption features in the full UV spectrum of the nearby (d = 24 pc) B8 IVn star alpha Leo (Regulus) obtained at high resolution and high S/N by the HST ASTRAL Treasury program. We derive column densities for many key atomic species and interpret their partial ionizations. The gas in front of alpha Leo exhibits two absorption components, one of which coincides in velocity with the local interstellar cloud (LIC) that surrounds the Sun. The second, smaller, component is shifted by +5.6 km/s relative to the main component, in agreement with results for other lines of sight in this region of the sky. The excitation of the C II fine-structure levels and the ratio of Mg I to Mg II reveal a temperature T = 6500 (+750,-600)K and electron density n(e) = 0.11 (+0.025,-0.03) cm^-3. Our investigation of the ionization balance of all the available species indicates that about 1/3 of the hydrogen atoms are ionized and that metals are significantly depleted onto grains. We infer that N(H I) = 1.9 (+...

  16. The impact of stellar feedback on hot gas in galaxy haloes: the Sunyaev-Zel'dovich effect and soft X-ray emission

    CERN Document Server

    van de Voort, Freeke; Hopkins, Philip F; Faucher-Giguère, Claude-André; Feldmann, Robert; Kereš, Dušan; Chan, T K; Hafen, Zachary H

    2016-01-01

    The thermal Sunyaev-Zel'dovich (SZ) effect and soft X-ray emission are routinely observed around massive galaxies and in galaxy groups and clusters. We study these observational diagnostics of galaxy haloes for a suite of cosmological `zoom-in' simulations from the `Feedback In Realistic Environments' project, which spans a large range in halo mass 10^10-10^13 Msun). We explore the effect of stellar feedback on the hot gas observables. The properties of our simulated groups, such as baryon fractions, SZ flux, and X-ray luminosities (L_X), are broadly consistent with existing observations, even though feedback from active galactic nuclei is not included. We make predictions for future observations of lower-mass objects for both SZ and diffuse X-ray measurements, finding that they are not just scaled-down versions of massive galaxies, but more strongly affected by galactic winds driven by star formation. Low-mass haloes (~10^13 Msun, on the other hand, L_X is much less variable and not correlated with the SFR, ...

  17. Hot gas ingestion testing of an advanced STOVL concept in the NASA Lewis 9- by 15-foot Low Speed Wind Tunnel with flow visualization

    Science.gov (United States)

    Johns, Albert L.; Flood, Joseph D.; Strock, Thomas W.; Amuedo, Kurt C.

    1988-01-01

    Advanced Short Takeoff/Vertical Landing (STOVL) aircraft capable of operating from remote sites, damaged runways, and small air capable ships are being pursued for deployment around the turn of the century. To achieve this goal, it is important that the technologies critical to this unique class of aircraft be developed. Recognizing this need, NASA Lewis Research Center, McDonnell Douglas Aircraft, and DARPA defined a cooperative program for testing in the NASA Lewis 9- by 15-foot Low Speed Wind Tunnel (LSWT) to establish a database for hot gas ingestion, one of the technologies critical to STOVL. Results from a test program are presented along with a discussion of the facility modifications allowing this type of testing at modal scale. These modifications to the tunnel include a novel ground plane, an elaborate model support which included 4 degrees of freedom, heated high pressure air for nozzle flow, a suction system exhaust for inlet flow, and tunnel sidewall modifications. Several flow visualization techniques were employed including water mist in the nozzle flows and tufts on the ground plane. Headwind (free-stream) velocity was varied from 8 to 23 knots.

  18. Results of tests of K5NA and a revised formulation of EPDM/cork patch material in MSFC Hot Gas Facility

    Science.gov (United States)

    Dean, W. G.

    1982-01-01

    During prelaunch procedures at Kennedy Space Center some of the EPDM Thermal Protection System material was damaged on the Solid Rocket Booster stiffener stubs. The preferred solution was to patch the damaged areas with a cork-filled epoxy patching compound. Before this was done, however, it was requested that this patching technique be checked out by testing it in the MSFC Hot Gas Facility. Two tests were run in the HFG in 1980. The results showed the patch material to be adequate. Since that time, the formulation of the cork-filled epoxy material has been changed. It became necessary to retest this concept to be sure that the new material is as good as or better than the original material. In addition to the revised formulation material, tests were also made using K5NA as the patch material. The objectives of the tests reported herein were to: (1) compare the thermal performance of the original and the new cork-filled epoxy formulations, and (2) compare the K5NA closeout material to these epoxy materials. Material specifications are also discussed.

  19. Combined effects Na and SO2 in flue gas on Mn-Ce/TiO2 catalyst for low temperature selective catalytic reduction of NO by NH3 simulated by Na2SO4 doping

    Science.gov (United States)

    Zhou, Aiyi; Yu, Danqing; Yang, Liu; Sheng, Zhongyi

    2016-08-01

    A series of Mn-Ce/TiO2 catalysts were synthesized through an impregnation method and used for low temperature selective catalytic reduction (SCR) of NOx with ammonia (NH3). Na2SO4 was added into the catalyst to simulate the combined effects of alkali metal and SO2 in the flue gas. Experimental results showed that Na2SO4 had strong and fluctuant influence on the activity of Mn-Ce/TiO2, because the effect of Na2SO4 included pore occlusion and sulfation effect simultaneously. When Na2SO4 loading content increased from 0 to 1 wt.%, the SCR activities of Na2SO4-doped catalysts decreased greatly. With further increasing amount of Na2SO4, however, the catalytic activity increased gradually. XRD results showed that Na2SO4 doping could induce the crystallization of MnOx phases, which were also confirmed by TEM and SEM results. BET results showed that the surface areas decreased and a new bimodal mesoporous structure formed gradually with the increasing amount of Na2SO4. XPS results indicated that part of Ce4+ and Mn3+ were transferred to Ce3+ and Mn4+ due to the sulfation after Na2SO4 deposition on the surface of the catalysts. When the doped amounts of Na2SO4 increased, NH3-TPD results showed that the Lewis acid sites decreased and the Brønsted acid sites of Mn-Ce/TiO2 increased quickly, which could be considered as another reason for the observed changes in the catalytic activity. The decreased Mn and Ce atomic concentration, the changes of their oxidative states, and the variation in acidic properties on the surface of Na2SO4-doped catalysts could be the reasons for the fluctuant changes of the catalytic activity.

  20. IR Hot Wave

    Energy Technology Data Exchange (ETDEWEB)

    Graham, T. B.

    2010-04-01

    The IR Hot Wave{trademark} furnace is a breakthrough heat treatment system for manufacturing metal components. Near-infrared (IR) radiant energy combines with IR convective heating for heat treating. Heat treatment is an essential process in the manufacture of most components. The controlled heating and cooling of a metal or metal alloy alters its physical, mechanical, and sometimes chemical properties without changing the object's shape. The IR Hot Wave{trademark} furnace offers the simplest, quickest, most efficient, and cost-effective heat treatment option for metals and metal alloys. Compared with other heat treatment alternatives, the IR Hot Wave{trademark} system: (1) is 3 to 15 times faster; (2) is 2 to 3 times more energy efficient; (3) is 20% to 50% more cost-effective; (4) has a {+-}1 C thermal profile compared to a {+-}10 C thermal profile for conventional gas furnaces; and (5) has a 25% to 50% smaller footprint.

  1. Characterization and catalytic performance of CeO2-Co/SiO2 catalyst for Fischer-Tropsch synthesis using nitrogen-diluted synthesis gas over a laboratory scale fixed-bed reactor

    Institute of Scientific and Technical Information of China (English)

    Xiaoping Dai; Changchun Yu

    2008-01-01

    The surface species of CO hydrogenation on CeO2-Co/SiO2 catalyst were investigated using the techniques of temperature programmed reaction and transient response method. The results indicated that the formation of H2O and CO2 was the competitive reaction for the surface oxygen species, CH4 was produced via the hydrogenation of carbon species step by step, and C2 products were formed by the polymerization of surface-active carbon species (-CH2-). Hydrogen assisted the dissociation of CO. The hydrogenation of surface carbon species was the rate-limiting step in the hydrogenation of CO over CeO2-Co/SiO2 catalyst. The investigation of total pressure, gas hourly space velocity (GHSV), and product distribution using nitrogen-rich synthesis gas as feedstock over a laboratory scale fixed-bed reactor indicated that total pressure and GHSV had a significant effect on the catalytic performance of CeO2-Co/SiO2 catalyst. The removal of heat and control of the reaction temperature were extremely critical steps, which required lower GHSV and appropriate CO conversion to avoid the deactivation of the catalyst. The feedstock of nitrogen-rich synthesis gas was favorable to increase the conversion of CO, but there was a shift of product distribution toward the light hydrocarbon. The nitrogen-rich synthesis gas was feasible for F-T synthesis for the utilization of remote natural gas.

  2. Application of new type catalytic method desulfurization technology in sulfuric acid tail gas treatment engineering%新型催化法脱硫技术在硫酸尾气处理工程上的应用

    Institute of Scientific and Technical Information of China (English)

    李新; 李月丽; 李建军; 尹华强

    2012-01-01

    Based on the analysis of the present situation of sulfuric acid tail gas treatment and the existing problems of commonly used technology, a new type catalytic desulfurization technology including the basic principle, the process and engineering project for the treatment of sulfuric acid tail gas and recovery sulfur resources is introduced. Compared with the traditional ammonia-acid method, activated char method, limestone-gypsum method, the new type catalytic method uses low temperature non-vanadium catalyst, can effectively remove the SO2 in sulfuric acid tail gas, to ensure p(SO2) 〈 50 mg/m3, meeting the new standards, the technology has broad application prospect in sulfuric acid tail gas treatment.%分析目前硫酸尾气治理现状及常用技术存在的问题,介绍一种新型催化脱硫技术处理硫酸尾气并回收硫资源的基本原理、工艺流程和工程实例。与传统的氨-酸法、活性焦法、石灰石-石膏法对比,新型催化法技术采用低温非钒系催化剂可有效脱除硫酸尾气中的SO2,保证ρ(SO2)〈50mg/m^3,达到新标准所规定的限值。该方法处理硫酸尾气具有广阔的应用前景。

  3. Hot conditioning equipment conceptual design report

    Energy Technology Data Exchange (ETDEWEB)

    Bradshaw, F.W., Westinghouse Hanford

    1996-08-06

    This report documents the conceptual design of the Hot Conditioning System Equipment. The Hot conditioning System will consist of two separate designs: the Hot Conditioning System Equipment; and the Hot Conditioning System Annex. The Hot Conditioning System Equipment Design includes the equipment such as ovens, vacuum pumps, inert gas delivery systems, etc.necessary to condition spent nuclear fuel currently in storage in the K Basins of the Hanford Site. The Hot Conditioning System Annex consists of the facility of house the Hot Conditioning System. The Hot Conditioning System will be housed in an annex to the Canister Storage Building. The Hot Conditioning System will consist of pits in the floor which contain ovens in which the spent nuclear will be conditioned prior to interim storage.

  4. Hot conditioning equipment conceptual design report

    International Nuclear Information System (INIS)

    This report documents the conceptual design of the Hot Conditioning System Equipment. The Hot conditioning System will consist of two separate designs: the Hot Conditioning System Equipment; and the Hot Conditioning System Annex. The Hot Conditioning System Equipment Design includes the equipment such as ovens, vacuum pumps, inert gas delivery systems, etc.necessary to condition spent nuclear fuel currently in storage in the K Basins of the Hanford Site. The Hot Conditioning System Annex consists of the facility of house the Hot Conditioning System. The Hot Conditioning System will be housed in an annex to the Canister Storage Building. The Hot Conditioning System will consist of pits in the floor which contain ovens in which the spent nuclear will be conditioned prior to interim storage

  5. Catalytic pyrolysis of oilsand bitumen over nanoporous catalysts.

    Science.gov (United States)

    Lee, See-Hoon; Heo, Hyeon Su; Jeong, Kwang-Eun; Yim, Jin-Heong; Jeon, Jong-Ki; Jung, Kyeong Youl; Ko, Young Soo; Kim, Seung-Soo; Park, Young-Kwon

    2011-01-01

    The catalytic cracking of oilsand bitumen was performed over nanoporous materials at atmospheric conditions. The yield of gas increased with application of nanoporous catalysts, with the catalytic conversion to gas highest for Meso-MFI. The cracking activity seemed to correlate with pore size rather than weak acidity or surface area. PMID:21446540

  6. 天然气低碳催化燃烧烤箱的应用及烟气对大气的影响%Research on Application of Low Carbon Catalytic Combustion Oven by Natural Gas and Influence of its Exhaust Gas to Atmosphere

    Institute of Scientific and Technical Information of China (English)

    张世红; 何繁; 房凯; 于哲

    2015-01-01

    Catalytic combustion is a new type of combustion which oxidized natural gas completely with high combustion efficiency, near_zero pollutant emissions. They were environmentally friendly energy_saving combustion devices. The experiment of roasted meat inside catalytic combustion oven V is discussed in the paper in order to verify the feasibility of the application of catalytic combustion technology in the food processing of meat. The finished product was analyzed from the catalytic combustion oven. Such as roasted duck, the result of experiment shows generally that saving energy and environmental protection by catalytic combustion oven for roasted food are better than that of conventional oven. There is distinguishing feature about the taste and quality of the roasted duck by catalytic combustion oven.%天然气催化燃烧是一种新型的燃烧方式,具有天然气燃烧完全、燃烧效率高、近零污染物排放等优点,是一种环保节能的燃烧方式。利用催化燃烧V型烤箱进行肉食加工的应用实验,验证关于催化燃烧技术在肉类食品加工方面的应用可行性,并对催化燃烧烧制出的成品进行分析。以烤鸭为例,综合说明利用催化燃烧烤箱烧制的肉类食品比传统烧制方法更节能环保,并且在口感和质量上比传统方法烧制的烤鸭更有特色。

  7. SELECTIVE CATALYTIC REDUCTION MERCURY FIELD SAMPLING PROJECT

    Science.gov (United States)

    A lack of data still exists as to the effect of selective catalytic reduction (SCR), selective noncatalytic reduction (SNCR), and flue gas conditioning on the speciation and removal of mercury (Hg) at power plants. This project investigates the impact that SCR, SNCR, and flue gas...

  8. 攀钢干热高炉煤气直送利用技术的探索与应用%The Exploration and Application of the Technology of Direct Supply of Hot Blast Furnace Gas

    Institute of Scientific and Technical Information of China (English)

    吕勇; 李苹

    2015-01-01

    通过对高炉煤气利用现状及性能分析,明确高炉煤气潜在利用价值,实施了干热高炉煤气直送利用技术,降低了高炉焦比,提高了煤气利用效率.%Through analysis of the present situation and performance of utilization of blast furnace gas, the potential utilization value of blast furnace gas was clarified. The tech-nology of direct delivery and utilization of dry hot blast furnace gas was implemented, which has lowered the coke rate of blast furnace and increased gas utilization efficiency.

  9. Bifunctional catalytic electrode

    Science.gov (United States)

    Cisar, Alan (Inventor); Murphy, Oliver J. (Inventor); Clarke, Eric (Inventor)

    2005-01-01

    The present invention relates to an oxygen electrode for a unitized regenerative hydrogen-oxygen fuel cell and the unitized regenerative fuel cell having the oxygen electrode. The oxygen electrode contains components electrocatalytically active for the evolution of oxygen from water and the reduction of oxygen to water, and has a structure that supports the flow of both water and gases between the catalytically active surface and a flow field or electrode chamber for bulk flow of the fluids. The electrode has an electrocatalyst layer and a diffusion backing layer interspersed with hydrophilic and hydrophobic regions. The diffusion backing layer consists of a metal core having gas diffusion structures bonded to the metal core.

  10. Catalytic gasification of biomass

    Science.gov (United States)

    Robertus, R. J.; Mudge, L. K.; Sealock, L. J., Jr.; Mitchell, D. H.; Weber, S. L.

    1981-12-01

    Methane and methanol synthesis gas can be produced by steam gasification of biomass in the presence of appropriate catalysts. This concept is to use catalysts in a fluidized bed reactor which is heated indirectly. The objective is to determine the technical and economic feasibility of the concept. Technically the concept has been demonstrated on a 50 lb per hr scale. Potential advantages over conventional processes include: no oxygen plant is needed, little tar is produced so gas and water treatment are simplified, and yields and efficiencies are greater than obtained by conventional gasification. Economic studies for a plant processing 2000 T/per day dry wood show that the cost of methanol from wood by catalytic gasification is competitive with the current price of methanol. Similar studies show the cost of methane from wood is competitive with projected future costs of synthetic natural gas. When the plant capacity is decreased to 200 T per day dry wood, neither product is very attractive in today's market.

  11. CFD analysis of hot spot formation through a fixed bed reactor of Fischer-Tropsch synthesis

    Directory of Open Access Journals (Sweden)

    Hamed Aligolzadeh

    2015-12-01

    Full Text Available One of the interesting methods for conversion of synthesis gas to heavy hydrocarbons is Fischer–Tropsch process. The process has some bottlenecks, such as hot spot formation and low degree of conversion. In this work, computational fluid dynamics technique was used to simulate conversion of synthetic gas and product distribution. Also, hot spot formation in the catalytic fixed-bed reactor was investigated in several runs. Simulation results indicated that hot spot formation occurred more likely in the early and middle part of reactor due to high reaction rates. Based on the simulation results, the temperature of hot spots increased with increase in the inlet temperature as well as pressure. Among the many CFD runs conducted, it is found that the optimal temperature and pressure for Fischer–Tropsch synthesis are 565 K and 20 bar, respectively. As it seems that the reactor shall work very well under optimal conditions, the reaction rates and catalyst duration would simultaneously be maximum .

  12. Reforming of methane in tubes with a catalytic active wall

    International Nuclear Information System (INIS)

    The heterogeneous steam reforming process in tubes with catalytic active inner surface is studied. The purpose of this ivestigation is to find a method of predicting the reaction rate of the catalytic conversion of methane by steam. The dependency of the reaction rate upon the temperature, pressure, gas composition, Reynolds number, geometrical sizes of tubes and catalytic behaviour of the catalytic active inner wall of these tubes has been examined. It was found that the reaction rate mainly depends on the temperature. The reaction rate is limited by the catalytic behaviour and the heat resisting properties of the materials used. (author)

  13. Fluid-Bed Testing of Greatpoint Energy's Direct Oxygen Injection Catalytic Gasification Process for Synthetic Natural Gas and Hydrogen Coproduction Year 6 - Activity 1.14 - Development of a National Center for Hydrogen Technology

    Energy Technology Data Exchange (ETDEWEB)

    Swanson, Michael; Henderson, Ann

    2012-04-01

    The GreatPoint Energy (GPE) concept for producing synthetic natural gas and hydrogen from coal involves the catalytic gasification of coal and carbon. GPE’s technology “refines” coal by employing a novel catalyst to “crack” the carbon bonds and transform the coal into cleanburning methane (natural gas) and hydrogen. The GPE mild “catalytic” gasifier design and operating conditions result in reactor components that are less expensive and produce pipeline-grade methane and relatively high purity hydrogen. The system operates extremely efficiently on very low cost carbon sources such as lignites, subbituminous coals, tar sands, petcoke, and petroleum residual oil. In addition, GPE’s catalytic coal gasification process eliminates troublesome ash removal and slagging problems, reduces maintenance requirements, and increases thermal efficiency, significantly reducing the size of the air separation plant (a system that alone accounts for 20% of the capital cost of most gasification systems) in the catalytic gasification process. Energy & Environmental Research Center (EERC) pilot-scale gasification facilities were used to demonstrate how coal and catalyst are fed into a fluid-bed reactor with pressurized steam and a small amount of oxygen to “fluidize” the mixture and ensure constant contact between the catalyst and the carbon particles. In this environment, the catalyst facilitates multiple chemical reactions between the carbon and the steam on the surface of the coal. These reactions generate a mixture of predominantly methane, hydrogen, and carbon dioxide. Product gases from the process are sent to a gas-cleaning system where CO{sub 2} and other contaminants are removed. In a full-scale system, catalyst would be recovered from the bottom of the gasifier and recycled back into the fluid-bed reactor. The by-products (such as sulfur, nitrogen, and CO{sub 2}) would be captured and could be sold to the chemicals and petroleum industries, resulting in

  14. Comparison between a Water-Based and a Solvent-Based Impregnation Method towards Dispersed CuO/SBA-15 Catalysts: Texture, Structure and Catalytic Performance in Automotive Exhaust Gas Abatement

    Directory of Open Access Journals (Sweden)

    Qi Xin

    2016-10-01

    Full Text Available Supported copper oxide nanoparticles are a potential candidate for replacing the rare and expensive precious metals within the automotive three-way catalyst. However, a well-designed dispersion method is necessary to allow a stable high loading of active material, compensating its lower intrinsic activity and stability. In this work, a CuO-loaded SBA-15 catalyst has been manufactured by two methods. The ammonia-driven deposition precipitation (ADP and the molecular designed dispersion (MDD methods are both considered as efficient deposition methods to provide well-dispersed copper oxide-based catalysts. Their morphology, copper dispersion and the chemical state of copper were characterized and compared. Due to the differences in the synthesis approach, a difference in the obtained copper oxide phases has been observed, leading to a distinct behavior in the catalytic performance. The structure-activity correlation of both catalysts has also been revealed for automotive exhaust gas abatement. Results demonstrate that various copper species can be formed depending on the precursor–support interaction, affecting selectivity and conversion during the catalytic reaction.

  15. Materials for High-Temperature Catalytic Combustion

    OpenAIRE

    Ersson, Anders

    2003-01-01

    Catalytic combustion is an environmentally friendlytechnique to combust fuels in e.g. gas turbines. Introducing acatalyst into the combustion chamber of a gas turbine allowscombustion outside the normal flammability limits. Hence, theadiabatic flame temperature may be lowered below the thresholdtemperature for thermal NOXformation while maintaining a stable combustion.However, several challenges are connected to the application ofcatalytic combustion in gas turbines. The first part of thisthe...

  16. 气固下行床超短接触反应器催化技术及其发展%Catalytic Technology and Its Development of Gas-solid downer Quick - Contact Reactor

    Institute of Scientific and Technical Information of China (English)

    刘宏巍; 李健; 韩毅

    2009-01-01

    介绍了超短接触反应器的工业应用及其发展现状,指出气固下行床超短接触反应是一项新的催化工艺,它将过去气固上行逆重力场运动改变成气固下行顺重力场运动,从而减少了返混、缩短停留时间,能大幅度提高轻油收率.该反应系统也比较容易实现提升管催化裂化、催化裂解装置的改造,有利于降低装置建、改造成本.%The gas-solid downer quick-contact reaction is a new catalytic process, it changes the gas-solid upward inverse gravity field motion into the gas-solid downward gravity field motion, thereby reduces the backmixing, shortens the residence time and increases yield.In this paper,applications and development of the reactor were introduced.

  17. Improvement of flue gas selective catalytic reduction technology and equipment for propane dehydrogenation (PDH) unit%丙烷脱氢装置烟气脱硝技术与设备改造

    Institute of Scientific and Technical Information of China (English)

    刘唯奇; 张国甫; 高海见; 陈金锋

    2016-01-01

    为降低烟气中的氮氧化物含量,采用丹麦托普索公司催化剂和工艺技术,在烟气余热锅炉内增加脱硝段,以满足达标排放的目的.并与工程公司合作,优化脱硝注氨系统的工艺流程,减少氨水消耗量,降低氨逃逸浓度.技术与设备改进后,烟色得到改善,烟气中的NOx含量大幅降低,同时氨水消耗量低于设计值,产生了良好的环境效益和经济效益.%The NOx concentration in the flue gas is reduced for standardized emission by a selective catalytic reduction (SCR) reactor installed in the waste heat boiler.The catalyst and reactor design are provided by Denmark HALDOR TOPSOE.New ammonia injection process is studied with engineering company to reduce ammonia consumption and slip concentration.After the improvement of process and equipment,the colour of flue gas looks better than before.The flue gas NOx concentration is significantly decreased and ammonia consumption is lower than hte design value,which produce good environmental and economic benefits.

  18. Rapid Deployment of Rich Catalytic Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Richard S. Tuthill

    2004-06-10

    The overall objective of this research under the Turbines Program is the deployment of fuel flexible rich catalytic combustion technology into high-pressure ratio industrial gas turbines. The resulting combustion systems will provide fuel flexibility for gas turbines to burn coal derived synthesis gas or natural gas and achieve NO{sub x} emissions of 2 ppmvd or less (at 15 percent O{sub 2}), cost effectively. This advance will signify a major step towards environmentally friendly electric power generation and coal-based energy independence for the United States. Under Phase 1 of the Program, Pratt & Whitney (P&W) performed a system integration study of rich catalytic combustion in a small high-pressure ratio industrial gas turbine with a silo combustion system that is easily scalable to a larger multi-chamber gas turbine system. An implementation plan for this technology also was studied. The principal achievement of the Phase 1 effort was the sizing of the catalytic module in a manner which allowed a single reactor (rather than multiple reactors) to be used by the combustion system, a conclusion regarding the amount of air that should be allocated to the reaction zone to achieve low emissions, definition of a combustion staging strategy to achieve low emissions, and mechanical integration of a Ceramic Matrix Composite (CMC) combustor liner with the catalytic module.

  19. 催化干气制乙苯装置工业操作方案优化与应用%Optimization and Application of the Industrial Operation Scheme for Catalytic Dry Gas-to-Ethylbenzene Plant

    Institute of Scientific and Technical Information of China (English)

    申永贵; 郑长有; 孟令猛

    2013-01-01

      介绍了干气制乙苯装置两台烃化反应器并联运行的可行性、操作方案及运行数据。大庆炼化公司干气制乙苯装置两个阶段的烃化反应器并联的实践证明:无论是采用调和汽油生产方案,还是乙苯生产方案,烃化反应器的并联,解决了在不开干气压缩机条件下束缚装置提高干气进料量的瓶颈,有效提高了原料干气中的乙烯转化率、以及产品产量,且不影响产品质量;同时,还可以有效降低反应器压降,为催化干气制乙苯装置工业操作方案优化及节能降耗提供参考和借鉴。%  The feasibility, operation scheme and running results of parallel operation of two alkylation reactors in catalytic dry gas-to-ethylbenzene plant were discussed. The running results in Daqing Refining & Chemical Company(DRCC) show that the parallel operation of two alkylation reactors is feasibility, and the parallel operation can break the bottleneck that restrict the increasing of the catalytic dry gas feed rate, improve ethylene conversion and product output, and dose not affect product quality. At the same time, the pressure drop of reactors can be effectively decreased.

  20. Four new WMO/GAW Observatories for the investigation of trace gas and aerosol variability in the Mediterranean hot-spot

    Science.gov (United States)

    Cristofanelli, Paolo; Marinoni, Angela; Duchi, Rocco; Busetto, Maurizio; Calzolari, Francescopiero; Bourcier, Laureline; Landi, Tony Christian; Calidonna, Claudia; Contini, Daniele; Ammoscato, Ivano; Gulli', Daniel; Dinoi, Adelaide; Sprovieri, Francesca; Carbone, Francesco; Naccarato, Attilio; Mannarino, Valentino; Pirrone, Nicola; Bonasoni, Paolo

    2016-04-01

    The Mediterranean Basin is considered a hot-spot region in term of air-quality and climate change due to the impact of anthropogenic and natural processes. Nevertheless, permanent infrastructures for the observations and the recognition of the atmospheric composition variability changes are still too sparse in this region. To contribute to a more accurate and wide-spread observation system, in the framework of the Project "I-AMICA" - Advanced Infrastructure for the Environmental-Climatic Monitoring (a three years Italian National Operative Program - PON, co-founded by the European Regional Development Fund), four permanent Climatic-Environmental Observatories have been set up in the southern Italy: Lecce (Apulia Region, 40° 20' 8" N, 18° 07' 28" E, 37 m a.s.l.), Lamezia Terme (Calabria Region, 38° 52' 34" N, 16° 13' 56" E, 6 m a.s.l.), Capo Granitola (Sicily, 37° 34' N, 12° 39' E, 5 m a.s.l.) and Mt. Curcio (Calabria, 39° 31' N, 16° 42' E, 1796 m a.s.l). These Observatories were equipped with homogeneous and standardized experimental set-up for measurements of aerosol properties (number size distribution, absorption and scattering coefficient, mass, equivalent black carbon), reactive and greenhouse gases (O3, NO, NO2, SO2, CO, CO2, CH4). The I-AMICA Observatories represent different conditions of the Mediterranean region, from suburban conditions at Lecce to costal background conditions at Lamezia Terme and Capo Granitola and high-mountain remote conditions at Mt. Curcio. The integration of the information from this high-quality observation network can be used for studies of aerosol transport from marine environment and Sahara desert, as well as for investigation of secondary pollutants formation in the gaseous and aerosol phase, investigation of continental outflow to Mediterranean Sea, impacts of vessel emissions on regional air quality and trans-boundary pollution. In this work, we provide a preliminary overview of gas and aerosol variability, together

  1. Component Development to Accelerate Commercial Implementation of Ultra-Low Emissions Catalytic Combustion

    Energy Technology Data Exchange (ETDEWEB)

    McCarty, Jon; Berry, Brian; Lundberg, Kare; Anson, Orris

    2003-03-31

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

  2. Effect of H{sub 2}S on the catalytic decomposition of tar and ammonia with dolomite and sintered iron ore in synthetic gasification gas

    Energy Technology Data Exchange (ETDEWEB)

    Hepola, J. [VTT Energy, Espoo (Finland)

    1996-12-31

    The toluene-decomposing activity of calcined dolomite was not affected by the H{sub 2}S content of synthetic gasification gas. Iron was active with respect to toluene and ammonia at metallic state. The increase of the H{sub 2}S content of synthetic gasification gas (0 - 500 ppmv) decreased the tar-decomposing activity but not the ammonia- decomposing activity of sintered iron ore. (author) (12 refs.)

  3. Hot Money,Hot Problems

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    After emerging from the economic doldrums, developing economies are now confronted with a new danger-a flood of international hot money. But how has the speculative capital circumvented regulatory controls and what are the consequences concerning the stability of the developing world? Zhao Zhongwei, a senior researcher with the Institute of World Politics and Economics at the Chinese Academy of Social Sciences, discussed these issues in an article recently published in the China Securities Journal. Edited excerpts follow

  4. 基于陶瓷微热板的高温气体传感器研究%Study of high-temperature gas sensor based on ceramic micro-hot-plate

    Institute of Scientific and Technical Information of China (English)

    薛严冰; 唐祯安

    2011-01-01

    针对目前商用陶瓷气体传感器功耗大、封装困难等缺点,提出一种陶瓷微加工微热板式气体传感器的结构和无内引线封装的方式。通过光刻剥离的方法,在氧化铝陶瓷基底上制作出Pt微加热器及接触电极。采用激光微细加工技术,制作出不同结构参数的陶瓷微热板器件。从温度同加热功率的关系、热响应时间和微加热器稳定性等方面对微热板进行了测试和评价。结果表明,陶瓷微热板具有较低功耗和高温工作的优势,可稳定工作的温度达到600℃。作为热板的高温应用之一,研制了CH4气体传感器,在500℃的工作条件下,对CH4气有很好响应灵敏度,且对CO%A novel gas sensor based on micro-machined ceramic hot-plate and wire-free bonding is presented to overcome the shortcomings of high power consumption and packaging difficulty existing in the current commercial ceramic gas sensors.The Pt heater and contact electrodes were sputtered on alumina substrate by controlled lift-off processing.The devices with different parameters were fabricated using the laser micro-machining technique.The performance of the hot-plate was tested and evaluated from the following aspects:the relationship between temperature and heating power,thermal response time and the stability of the heater.The results show that the ceramic hot plates have advantages of lower power consumption and higher working temperature,and they can steadily work at temperature of 600 ℃.As one of the applications of the hot-plate working in high temperature,CH4 gas sensors were developed.The sensors have high sensitivity to CH4 under 500 ℃,and basically have no response to the interfering gas of CO.

  5. Prometheus Hot Leg Piping Concept

    Science.gov (United States)

    Gribik, Anastasia M.; DiLorenzo, Peter A.

    2007-01-01

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  6. Promethus Hot Leg Piping Concept

    International Nuclear Information System (INIS)

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept

  7. Promethus Hot Leg Piping Concept

    Energy Technology Data Exchange (ETDEWEB)

    AM Girbik; PA Dilorenzo

    2006-01-24

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  8. 氧气与二氧化碳非催化重整焦炉煤气%NON-CATALYTIC REFORMING COKE OVEN GAS WITH O2 AND CO2

    Institute of Scientific and Technical Information of China (English)

    申曙光; 张翠; 秦海峰; 赵志军

    2011-01-01

    Reaction of non-catalytic reforming simulating coke oven gas with O2 and CO2 to synthesis gas was studied for the utilizination of coke oven gas and CO2 effectively. The effects of reaction temperatureand feed ratios were considered in the non-catalytic reforming coke oven gas with CO2 and O2 at the atmospheric pressure. The products were analyzed by gas chromatograph. The results showed that high reaction temperature favored non-catalytic reforming coke oven gas with O2 and CO2. The conversion of CH4 with increased remarkably with increasing the V(O2): V(CH4) ratio. While the conversion of CO2 and the yield of CO increased first and then decreased. The best V(O2) : V(CH4) ratio was 1.0 -1.1. The conversion of CH4 and the yield of CO decreased with increasing the V(CO2): V(CH4) ratio, but the conversion of CO2 increased at first and then decreased. The best V(CO2): V(CH4) ratio was 0.8- 0.9. In the definite volume of total oxygen, the reaction rules of increasing the V(O2 ):V (CO2) ratio was the same with the V(O2): V(CH4) ratio and the best V(O2) :V(CO2) ratio was 1.2-1.3. When the V(O2): V(CO2) ratio was 1.3, the conversion of CH4 and the yield of CO increased and the conversion of CO2 decreased with increasing the volume of total oxygen. The investigation manifested the method of non-catalytic reforming simulating coke oven gas with O2 and CO2 to synthesis gas was fine, in which the conversions of both CH4 and CO2 were 97% and 72%, respectively.%为了有效利用焦炉煤气和二氧化碳,开发了氧气与二氧化碳非催化重整焦炉煤气工艺,考察了反应温度、原料气配比对常压下氧气与二氧化碳非催化重整焦炉煤气反应的影响.利用气相色谱对产物进行了分析测定,结果表明:氧气与二氧化碳非催化重整焦炉煤气反应宜在高温条件下进行;V(O2)∶V(CH4)增大,有利于甲烷转化,二氧化碳转化率和一氧化碳收率则先增大后减小,最佳比值为(1.0~1.1)∶1;V(CO2)∶V(CH4

  9. CeO2-TiO2 catalysts for catalytic oxidation of elemental mercury in low-rank coal combustion flue gas.

    Science.gov (United States)

    Li, Hailong; Wu, Chang-Yu; Li, Ying; Zhang, Junying

    2011-09-01

    CeO(2)-TiO(2) (CeTi) catalysts synthesized by an ultrasound-assisted impregnation method were employed to oxidize elemental mercury (Hg(0)) in simulated low-rank (sub-bituminous and lignite) coal combustion flue gas. The CeTi catalysts with a CeO(2)/TiO(2) weight ratio of 1-2 exhibited high Hg(0) oxidation activity from 150 to 250 °C. The high concentrations of surface cerium and oxygen were responsible for their superior performance. Hg(0) oxidation over CeTi catalysts was proposed to follow the Langmuir-Hinshelwood mechanism whereby reactive species from adsorbed flue gas components react with adjacently adsorbed Hg(0). In the presence of O(2), a promotional effect of HCl, NO, and SO(2) on Hg(0) oxidation was observed. Without O(2), HCl and NO still promoted Hg(0) oxidation due to the surface oxygen, while SO(2) inhibited Hg(0) adsorption and subsequent oxidation. Water vapor also inhibited Hg(0) oxidation. HCl was the most effective flue gas component responsible for Hg(0) oxidation. However, the combination of SO(2) and NO without HCl also resulted in high Hg(0) oxidation efficiency. This superior oxidation capability is advantageous to Hg(0) oxidation in low-rank coal combustion flue gas with low HCl concentration. PMID:21770402

  10. In situ and operando transmission electron microscopy of catalytic materials

    DEFF Research Database (Denmark)

    Crozier, Peter A.; Hansen, Thomas Willum

    2015-01-01

    measurements of gas-phase catalytic products. To overcome this deficiency, operando TEM techniques are being developed that combine atomic characterization with the simultaneous measurement of catalytic products. This article provides a short review of the current status and major developments in the...

  11. Environmentally friendly analysis of emerging contaminants by pressurized hot water extraction-stir bar sorptive extraction-derivatization and gas chromatography-mass spectrometry

    OpenAIRE

    Pintado-Herrera, Marina G.; González-Mazo, Eduardo; Lara-Martín, Pablo A.

    2013-01-01

    This work describes the development, optimiza- tion, and validation of a new method for the simultaneous determination of a wide range of pharmaceuticals (beta- blockers, lipid regulators ... ) and personal care products (fragrances, UV filters, phthalates ... ) in both aqueous and solid environmental matrices. Target compounds were extracted from sediments using pressurized hot water ex- traction followed by stir bar sorptive extraction. The first stage wa...

  12. A self-heated silicon nanowire array: selective surface modification with catalytic nanoparticles by nanoscale Joule heating and its gas sensing applications.

    Science.gov (United States)

    Yun, Jeonghoon; Jin, Chun Yan; Ahn, Jae-Hyuk; Jeon, Seokwoo; Park, Inkyu

    2013-08-01

    We demonstrated novel methods for selective surface modification of silicon nanowire (SiNW) devices with catalytic metal nanoparticles by nanoscale Joule heating and local chemical reaction. The Joule heating of a SiNW generated a localized heat along the SiNW and produced endothermic reactions such as hydrothermal synthesis of nanoparticles or thermal decomposition of polymer thin films. In the first method, palladium (Pd) nanoparticles could be selectively synthesized and directly coated on a SiNW by the reduction of the Pd precursor via Joule heating of the SiNW. In the second method, a sequential process composed of thermal decomposition of a polymer, evaporation of a Pd thin film, and a lift-off process was utilized. The selective decoration of Pd nanoparticles on SiNW was successfully accomplished by using both methods. Finally, we demonstrated the applications of SiNWs decorated with Pd nanoparticles as hydrogen detectors. We also investigated the effect of self-heating of the SiNW sensor on its sensing performance. PMID:23770994

  13. Experimental Researches on Catalytic Reforming Gas into Scramjet Model Engine%超燃模型发动机中引入催化重整燃气的试验研究

    Institute of Scientific and Technical Information of China (English)

    侯凌云; 龚景松; 柳发成; 马雪松; 刘小勇

    2012-01-01

    催化重整燃烧室能够产生氢体积分数高达16%的高温富油可燃燃气,所产生的可燃燃气从后支板供入到超燃模型发动机中,进行了直连式联调试验.在相同超音速来流状态下,与不通入可燃燃气的两种工况进行了压力、出口火焰形貌和壁面温度的对比,发现可燃燃气的加入能够在几乎不加入高压气堵情况下迅速着火,并能维持住稳定的超音速燃烧,在富油恶劣状态下,燃烧良好.结果表明,催化重整可燃成分在超燃模型发动机中起到了助燃和稳定燃烧的作用.%Catalytic reforming combustor can produce high temperature and hydrogen-rich (volumetric fraction up to 16%) flammable gases, which are supplied into scramjet model engine from the back strut of scramjet model engine. Under the same supersonic inflowing conditions, ignition and combustion experiments on the engine are carried out between one case with flammable gas and the other two cases without flammable gases. Their wall pressures, temperatures and flames are compared. The results show that the adding of flammable gases can rapidly ignite, almost without back aerodynamic throat, and the stable combustion can be sustained even with rich fuel. It is demonstrated that flammable gases generated by catalytic reforming can be helpful in igniting and combusting in the hydrocarbon-fueled scramjet engine.

  14. Waste Heat Recovery Technology for the Flue Gas of Hot Rolling Heating Furnace%热轧加热炉烟气余热回收利用技术

    Institute of Scientific and Technical Information of China (English)

    刘伟

    2014-01-01

    介绍一种热轧加热炉烟气余热回收利用技术的系统流程、工艺设计方案、主要参数及经济效益。利用这套技术将加热炉烟气潜在余热进行梯级高效利用,并通过生产实践证明,达到了理想的应用效果。%The systematic process, technological design, main parameters and economic benefits of the waste heat recovery technology for the flue gas of hot rolling heating furnace are introduced.Potential waste heat from the heating furnace flue gas was efficiently utilized in a cascade model through adopting the technology, the ideal effect of which has been proved by production practice.

  15. An experimental study of diffusion and convection of multicomponent gases through catalytic and non-catalytic membranes

    NARCIS (Netherlands)

    Veldsink, J.W.; Versteeg, G.F.; Swaaij, W.P.M. van

    1994-01-01

    Diffusion of binary and ternary gases through catalytic and non-catalytic membranes has been studied experimentally at atmospheric pressure. These experiments were conducted in a modified Wicke-Kallenbach diffusion cell consisting of two continuously stirred gas volumes separated by a membrane. The

  16. Catalytic treatment of diesel engines, NOx emissions

    International Nuclear Information System (INIS)

    Some aspects of the operation of diesel engines are revised together with the pollutant emissions they produce, as well as the available catalytic technologies for the treatment of diesel emissions. Furthermore the performance of a catalyst developed in the environmental catalysis group for NOx reduction using synthetic gas mixtures simulating the emissions from diesel engines is presented

  17. Materials for High-Temperature Catalytic Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Ersson, Anders

    2003-04-01

    Catalytic combustion is an environmentally friendly technique to combust fuels in e.g. gas turbines. Introducing a catalyst into the combustion chamber of a gas turbine allows combustion outside the normal flammability limits. Hence, the adiabatic flame temperature may be lowered below the threshold temperature for thermal NO{sub X} formation while maintaining a stable combustion. However, several challenges are connected to the application of catalytic combustion in gas turbines. The first part of this thesis reviews the use of catalytic combustion in gas turbines. The influence of the fuel has been studied and compared over different catalyst materials. The material section is divided into two parts. The first concerns bimetallic palladium catalysts. These catalysts showed a more stable activity compared to their pure palladium counterparts for methane combustion. This was verified both by using an annular reactor at ambient pressure and a pilot-scale reactor at elevated pressures and flows closely resembling the ones found in a gas turbine combustor. The second part concerns high-temperature materials, which may be used either as active or washcoat materials. A novel group of materials for catalysis, i.e. garnets, has been synthesised and tested in combustion of methane, a low-heating value gas and diesel fuel. The garnets showed some interesting abilities especially for combustion of low-heating value, LHV, gas. Two other materials were also studied, i.e. spinels and hexa aluminates, both showed very promising thermal stability and the substituted hexa aluminates also showed a good catalytic activity. Finally, deactivation of the catalyst materials was studied. In this part the sulphur poisoning of palladium, platinum and the above-mentioned complex metal oxides has been studied for combustion of a LHV gas. Platinum and surprisingly the garnet were least deactivated. Palladium was severely affected for methane combustion while the other washcoat materials were

  18. 注热水盐度对水合物开采影响的实验研究%Experimental Studies on the Effects of Hot Brine Salinity on Gas Hydrate Production

    Institute of Scientific and Technical Information of China (English)

    李淑霞; 李杰; 曹文

    2015-01-01

    天然气水合物是目前备受关注的新型洁净优质能源,注热盐水是一种有效的开采方式。采用自制的一维天然气水合物(NGH)开采模拟实验装置,首先在填砂模型中生成初始条件相同的天然气水合物藏,之后注入盐度为2%、10%、20%的热水进行开采实验。结果表明:当注热水盐度较大(达到10%后)时,水合物快速分解,与自由气同时产出,产气速率峰值较大;而当注热水盐度较小(2%)时,自由气首先产出,然后水合物分解气体产出。注热水盐度越大,水合物分解速度越快,热前缘移动速率越大,水合物大量分解阶段的能量效率越高。因此,注热水盐度的增加可以加快天然气水合物的开采速率,增大注热开采的经济可行性。%Natural gas hydrate(NGH) is a new clean and effective energy resource. Hot brine injection is a successful mining method and the salinity of hot brine has big influence on the equilibrium of NGH. Therefore, how the salinity affects the thermal dissociation is very important. A self-made one-dimensional experimental setup was introduced to dissociate NGH with same initial conditions, and then hot brine with different salinities (2%,10%,20%) was injected to study the effect of hot brine salinity on NGH dissociation. Results show that brine salinity has a large effect on NGH dissociation. When the brine salinity was over 10%, NGH was dissociated fast and free gas from NGH dissociation was simultaneously produced that resulting in a large gas production rate. For 2% brine salinity, free gas production and gas release from NGH dissociation happened one after another. Higher brine salinity results in faster NGH dissociation rate, quicker thermal front movement of NGH and higher energy efficiency. Therefore, the NGH dissociation rate and the dissociation feasibility accelerated with the increase of hot brine salinity.

  19. Vacuum-insulated catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Benson, David K. (Golden, CO)

    2001-01-01

    A catalytic converter has an inner canister that contains catalyst-coated substrates and an outer canister that encloses an annular, variable vacuum insulation chamber surrounding the inner canister. An annular tank containing phase-change material for heat storage and release is positioned in the variable vacuum insulation chamber a distance spaced part from the inner canister. A reversible hydrogen getter in the variable vacuum insulation chamber, preferably on a surface of the heat storage tank, releases hydrogen into the variable vacuum insulation chamber to conduct heat when the phase-change material is hot and absorbs the hydrogen to limit heat transfer to radiation when the phase-change material is cool. A porous zeolite trap in the inner canister absorbs and retains hydrocarbons from the exhaust gases when the catalyst-coated substrates and zeolite trap are cold and releases the hydrocarbons for reaction on the catalyst-coated substrate when the zeolite trap and catalyst-coated substrate get hot.

  20. Catalytic Cracking Conversion of Tar Component in High Temperature Coal Gas%高温煤气中焦油组分的催化裂解

    Institute of Scientific and Technical Information of China (English)

    赵国靖; 李海涛; 豆斌林; 沙兴中

    2001-01-01

    在固定床反应器条件下对焦油组分(以1-甲基萘作为焦油的模型化合物)进行了催化裂解研究,选择镍基催化剂、5A分子筛、CaO催化剂、矾土和石英砂等5种催化剂为焦油组分裂解催化剂。研究表明此5种催化剂对1-甲基萘的裂解都具有催化活性,10h反应时间内,5A分子筛和Ni基催化剂对1-甲基萘的转化率为100%,CaO催化剂、矾土和石英砂对1-甲基萘的转化率则较低。同时研究了温度对Ni-3催化剂和5A分子筛的转化率的影响。为了进行比较也测试了Ni-3催化剂对苯的转化率,总包一级反应线性回归出催化剂在250~500℃的裂解活化能为22.17kJ/mol。%The tar decomposition activities of five catalysts including Nibased catalyst, alumina, 5A molecular sieve, CaO catalyst, quartz sand catalysts are compared in a fixed bed catalytic reactor. 1-methylnaphthalene is used as a tar model compound. All these catalysts show to be active and useful for tar cracking reactions, deactivations of Ni based and 5A molecular sieve catalyst are not found within 10 h reaction time with space velocity of 3 000 h-1 at temperature of 550 ℃. Especially, with increasing temperature, the conversion of 1-methylnaphthalene is improved. At same time, Ni-3 catalyst is found to be effective for benzene conversion at 550 ℃ and 650 ℃. Using a simple first-order kinetic model for the overall reaction, an apparent activation energies (22.17 kJ/mol for Ni-3 catalyst) is obtained at 250~500 ℃.

  1. Catalytic distillation structure

    Science.gov (United States)

    Smith, Jr., Lawrence A.

    1984-01-01

    Catalytic distillation structure for use in reaction distillation columns, a providing reaction sites and distillation structure and consisting of a catalyst component and a resilient component intimately associated therewith. The resilient component has at least about 70 volume % open space and being present with the catalyst component in an amount such that the catalytic distillation structure consist of at least 10 volume % open space.

  2. Catalytic combustor for hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Mercea, J.; Grecu, E.; Fodor, T.; Kreibik, S.

    1982-01-01

    The performance of catalytic combustors for hydrogen using platinum-supported catalysts is described. Catalytic plates of different sizes were constructed using fibrous and ceramic supports. The temperature distribution as well as the reaction efficiency as a function of the fuel input rate was determined, and a comparison between the performances of different plates is discussed.

  3. Catalytic production of biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Theilgaard Madsen, A.

    2011-07-01

    The focus of this thesis is the catalytic production of diesel from biomass, especially emphasising catalytic conversion of waste vegetable oils and fats. In chapter 1 an introduction to biofuels and a review on different catalytic methods for diesel production from biomass is given. Two of these methods have been used industrially for a number of years already, namely the transesterification (and esterification) of oils and fats with methanol to form fatty acid methyl esters (FAME), and the hydrodeoxygenation (HDO) of fats and oils to form straight-chain alkanes. Other possible routes to diesel include upgrading and deoxygenation of pyrolysis oils or aqueous sludge wastes, condensations and reductions of sugars in aqueous phase (aqueous-phase reforming, APR) for monofunctional hydrocarbons, and gasification of any type of biomass followed by Fischer-Tropsch-synthesis for alkane biofuels. These methods have not yet been industrialised, but may be more promising due to the larger abundance of their potential feedstocks, especially waste feedstocks. Chapter 2 deals with formation of FAME from waste fats and oils. A range of acidic catalysts were tested in a model fat mixture of methanol, lauric acid and trioctanoin. Sulphonic acid-functionalised ionic liquids showed extremely fast convertion of lauric acid to methyl laurate, and trioctanoate was converted to methyl octanoate within 24 h. A catalyst based on a sulphonated carbon-matrix made by pyrolysing (or carbonising) carbohydrates, so-called sulphonated pyrolysed sucrose (SPS), was optimised further. No systematic dependency on pyrolysis and sulphonation conditions could be obtained, however, with respect to esterification activity, but high activity was obtained in the model fat mixture. SPS impregnated on opel-cell Al{sub 2}O{sub 3} and microporous SiO{sub 2} (ISPS) was much less active in the esterification than the original SPS powder due to low loading and thereby low number of strongly acidic sites on the

  4. A theoretical study for one-dimensional modeling for VOC in a catalytic converter

    Science.gov (United States)

    Chauhan, S.; Sharma, L.; Srivastava, V. K.

    2010-07-01

    Modeling for catalytic oxidation of a volatile organic compound, acetaldehyde for the purpose of controlling tail-pipe emissions from vehicular exhaust was carried out. The model developed was one-dimensional unsteady state model, using mass and energy balance equations to predict results for acetaldehyde conversion in an adiabatic monolith operating under warm-up conditions. The equations consisted of a set of partial differential equations that are coupled and solved using Backward Implicit Scheme. Analysis of the behavior of the converter during warm up period was carried out and it was observed that the warm up was faster for a fresh catalyst and this warm up period could be reduced by introducing hot incoming exhaust gas at higher temperature.

  5. Rh promoted La0.75Sr0.25(Fe0.8Co0.2)1-xGaxO3-δ perovskite catalysts: Characterization and catalytic performance for methane partial oxidation to synthesis gas

    Science.gov (United States)

    Palcheva, R.; Olsbye, U.; Palcut, M.; Rauwel, P.; Tyuliev, G.; Velinov, N.; Fjellvåg, H. H.

    2015-12-01

    Synthesis gas production via selective oxidation of methane at 600 °C in a pulse reaction over La0.75Sr0.25(Fe0.8Co0.2)1-xGaxO3-δ (x = 0.1, 0.25, 0.4) perovskite-supported rhodium catalysts, was investigated. The perovskite oxides were prepared by sol-gel citrate method and characterized by X-ray Diffraction (XRD), Moessbauer Spectroscopy (MS), Temperature Programmed Reduction (TPR-H2), X-ray Photoelectron Spectroscopy (XPS) and High Resolution Transmission Electron Microscopy (HRTEM). According to XRD analysis, the synthesized samples were a single perovskite phase. The perovskite structure of Ga substituted samples remained stable after TPR-H2, as confirmed by XRD. Data of MS identified Fe3+ ions in two distinctive coordination environments, and Fe4+ ions. The Rh2O3 thin overlayer was detected by the HRTEM for the Rh impregnated perovskite oxides. During the interaction of methane with oxidized perovskite-supported Rh (0.5 wt.%) catalysts, besides CO, H2, and surface carbon, CO2 and H2O were formed. The Rh perovskite catalyst with x = 0.25 gallium exhibits the highest catalytic activity of 83% at 600 °C. The CO selectivity was affected by the reducibility of La0.75Sr0.25(Fe0.8Co0.2)1-xGaxO3-δ perovskite materials.

  6. 催化裂化油浆中硫化物气相色谱分析%Determination of Sulfur Compounds in Catalytic Cracking Slurry by Gas Chromatography With Sulfur Chemiluminescence Detection

    Institute of Scientific and Technical Information of China (English)

    何俊辉; 贾广信; 黎爱群; 薛晓军

    2014-01-01

    采用气相色谱配硫化学发光检测器(SCD)结合高温模拟蒸馏ASTM D7169-05方法对巴陵石化催化裂化油浆中含硫化合物进行了分析鉴定,结果表明:油浆的馏程在253℃到690℃左右范围内,硫化物类型主要是二苯并噻吩类和萘并噻吩类化合物;定量分析结果表明,萘并噻吩类化合物占油浆中总硫化物含量的70%以上。%The catalytic cracking slurry was analyzed by gas chromatography with sulfur chemiluminescence detection (GC-SCD) and SimDis ASTM D7169-05 method. The results show that distillation range of the slurry is from 253 ℃to 690 ℃,and main sulfide types are dibenzothiophenes and naphthothiophenes. Quantitative analysis results show that naphthothiophene compounds account for more than 70%of the total sulfur content in the slurry.

  7. Catalytic gasification of oil-shales

    Energy Technology Data Exchange (ETDEWEB)

    Lapidus, A.; Avakyan, T. [I.M. Gubkin Russian State Univ. of Oil and Gas, Moscow (Russian Federation); Strizhakova, Yu. [Samara State Univ. (Russian Federation)

    2012-07-01

    Nowadays, the problem of complex usage of solid fossil fuels as raw materials for obtaining of motor fuels and chemical products is becoming increasingly important. A one of possible solutions of the problem is their gasification with further processing of gaseous and liquid products. In this work we have investigated the process of thermal and catalytic gasification of Baltic and Kashpir oil-shales. We have shown that, as compared with non-catalytic process, using of nickel catalyst in the reaction increases the yield of gas, as well as hydrogen content in it, and decreases the amount of liquid products. (orig.)

  8. La catalyse d'épuration des gaz d'échappement automobiles. Situation actuelle et nouvelles orientations Catalytic Automotive Exhaust Gas Depollution. Present Status and New Trends

    Directory of Open Access Journals (Sweden)

    Prigent M.

    2006-11-01

    Full Text Available Cet article passe en revue les différents systèmes catalytiques de post-traitement utilisés actuellement sur la plupart des automobiles pour limiter leurs rejets de polluants. Les systèmes sont différenciés par leur mode de fonctionnement, le type de moteur à dépolluer (deux-temps, quatre-temps, diesel ou essence ou par leur mode de réalisation. Les nouvelles orientations, prévues pour respecter les futures réglementations antipollution, sont également décrites. On montre que certains véhicules prototypes, équipés de moteurs à combustion interne, sont capables d'avoir des émissions très proches de zéro tout comme les véhicules électriques. A review is made of the various types of exhaust gas aftertreatment systems presently used on most vehicles to reduce pollutant emissions. The systems are differentiated by their mode of action, according to the engine type to be depolluted (two-stroke, four-stroke, diesel or spark-ignition, and by their type of make-up. The major developments foreseen in the future, in view of compliance with the new legislations, are described. It is shown that some prototype vehicles with internal combustion engines are able to emit pollutant quantities really close to zero, such as electric cars.

  9. Preparation and High-Temperature Water-Gas Shift Catalytic Features of La1-xCexFeO3 Perovskite

    Institute of Scientific and Technical Information of China (English)

    马红钦; 朱慧铭; 谭欣; 张继炎; 张鎏

    2004-01-01

    Based on water-gas shift reaction mechanism and perovskite compounds characteristics, La1-xCexFeO3 (.K) perovskite were designed and prepared as shift catalysts. DTA and XRD results reveal that La1-xCexFeO3 can be formed at 730~760 ℃ by mechanic-mix thermal decomposition method. Activity and heat-resisting tests show that La1-xCexFeO3 (.K) possess high thermal stability if x is less than or equals to 0.5. But when x is greater than 0.5, La1-xCexFeO3 (.K) will be converted into ceria and magnetite partially or completely under shift reaction conditions. In the case of x=0.5, the conversion of CO is about 68% at 530 ℃. Potassium can greatly improve the low temperature activity, but slightly reduces the high temperature activity, and has little impact on the thermal stability. La0.5Ce0.5FeO3 (.K) is a promising chromium-free high temperature shift catalyst.

  10. Effect of Pd or Ir on the catalytic performance of Mo/H-ZSM-5 during the non-oxidative conversion of natural gas to petrochemicals

    Institute of Scientific and Technical Information of China (English)

    Ahmed K.Aboul-Gheit; Ahmed E.Awadallah; Salah M.El-Kossy; Abdel-Lateef H.Mahmoud

    2008-01-01

    Natural gas conversion to petrochemicals, principally, benzene, naphthalene, toluene, as well as ethylene under non-oxidative conditions was examined in a fixed bed flow reactor at 700 ℃ and gaseous hourly space velocity (GHSV) of 1500 ml·g-1·h-1 at time-on-stream ranging from 5 min to 4 h using catalysts containing 6.0%Mo/H-ZSM-5 promoted with Pd or Ir metal. The catalysts were characterized by XRD, TPD, and TGA. The addition of Pd or Ir to 6%Mo/H-ZSM-5 catalyst promoted ethylene production but inhibited the cyclization reaction to aromatics owing to the strong interaction between these noble metals and the framework Al species, which were attached to the acid sites during the impregnation process. Coke deposition on the catalysts was found to decrease upon addition of 0.5wt% of Pd or Ir to 6%Mo/H-ZSM-5 catalyst owing to the hydrogenating activity of these metals.

  11. Image-Processing-Based Study of the Interfacial Behavior of the Countercurrent Gas-Liquid Two-Phase Flow in a Hot Leg of a PWR

    Directory of Open Access Journals (Sweden)

    Gustavo A. Montoya

    2012-01-01

    Full Text Available The interfacial behavior during countercurrent two-phase flow of air-water and steam-water in a model of a PWR hot leg was studied quantitatively using digital image processing of a subsequent recorded video images of the experimental series obtained from the TOPFLOW facility, Helmholtz-Zentrum Dresden-Rossendorf e.V. (HZDR, Dresden, Germany. The developed image processing technique provides the transient data of water level inside the hot leg channel up to flooding condition. In this technique, the filters such as median and Gaussian were used to eliminate the drops and the bubbles from the interface and the wall of the test section. A Statistical treatment (average, standard deviation, and probability distribution function (PDF of the obtained water level data was carried out also to identify the flow behaviors. The obtained data are characterized by a high resolution in space and time, which makes them suitable for the development and validation of CFD-grade closure models, for example, for two-fluid model. This information is essential also for the development of mechanistic modeling on the relating phenomenon. It was clarified that the local water level at the crest of the hydraulic jump is strongly affected by the liquid properties.

  12. Catalytic microreactors for portable power generation

    Energy Technology Data Exchange (ETDEWEB)

    Karagiannidis, Symeon [Paul Scherer Institute, Villigen (Switzerland)

    2011-07-01

    ''Catalytic Microreactors for Portable Power Generation'' addresses a problem of high relevance and increased complexity in energy technology. This thesis outlines an investigation into catalytic and gas-phase combustion characteristics in channel-flow, platinum-coated microreactors. The emphasis of the study is on microreactor/microturbine concepts for portable power generation and the fuels of interest are methane and propane. The author carefully describes numerical and experimental techniques, providing a new insight into the complex interactions between chemical kinetics and molecular transport processes, as well as giving the first detailed report of hetero-/homogeneous chemical reaction mechanisms for catalytic propane combustion. The outcome of this work will be widely applied to the industrial design of micro- and mesoscale combustors. (orig.)

  13. Use catalytic combustion for LHV gases

    Energy Technology Data Exchange (ETDEWEB)

    Tucci, E.R.

    1982-03-01

    This paper shows how low heating value (LHV) waste gases can be combusted to recover energy even when the gases won't burn in a normal manner. Significant energy and economic savings can result by adopting this process. Catalytic combustion is a heterogeneous surface-catalyzed air oxidation of fuel, gaseous or liquid, to generate thermal energy in a flameless mode. The catalytic combustion process is quite complex since it involves numerous catalytic surface and gas-phase chemical reactions. During low temperature surface-catalyzed combustion, as in start-up, the combustion stage is under kinetically controlled conditions. The discussion covers the following topics - combustor substrates; combustor washcoating and catalyzing; combustor operational modes (turbine or tabular modes); applications in coal gasification and in-situ gasification; waste process gases. 16 refs.

  14. Formation of (FexMn(2-x))O3 solid solution and high sulfur capacity properties of Mn-based/M41 sorbents for hot coal gas desulfurization.

    Science.gov (United States)

    Zhang, Y; Liu, B S; Zhang, F M; Zhang, Z F

    2013-03-15

    Several MCM-41 materials were synthesized at different conditions by hydrothermal procedure using cheap and easily available industrial water glass as silica source. Fe doped manganese-based oxide/MCM-41 sorbents were prepared by a sol-gel method. The effects of loadings of metal oxide, Fe/Mn molar ratios over MCM-41 and reaction temperature on the performance of sorbent for hot coal gas desulfurization were investigated. Various techniques such as BET, XRD, XPS, LRS and HRTEM were used to characterize the sorbents. The result indicated Fe(3+) ions could occupy a position of Mn(3+) in cubic lattice of Mn2O3 and the (FexMn2-x)O3 solid solution is mainly active phase of sorbent. Moreover, the result of nine successive sulfurization-regeneration cycles of sorbent showed high sulfur adsorption capacity and endurable stability of FeMn4Ox/MCM-41 for H2S removal. PMID:23337625

  15. Catalytic distillation process

    Science.gov (United States)

    Smith, Jr., Lawrence A.

    1982-01-01

    A method for conducting chemical reactions and fractionation of the reaction mixture comprising feeding reactants to a distillation column reactor into a feed zone and concurrently contacting the reactants with a fixed bed catalytic packing to concurrently carry out the reaction and fractionate the reaction mixture. For example, a method for preparing methyl tertiary butyl ether in high purity from a mixed feed stream of isobutene and normal butene comprising feeding the mixed feed stream to a distillation column reactor into a feed zone at the lower end of a distillation reaction zone, and methanol into the upper end of said distillation reaction zone, which is packed with a properly supported cationic ion exchange resin, contacting the C.sub.4 feed and methanol with the catalytic distillation packing to react methanol and isobutene, and concurrently fractionating the ether from the column below the catalytic zone and removing normal butene overhead above the catalytic zone.

  16. Catalytic Functions of Standards

    NARCIS (Netherlands)

    K. Blind (Knut)

    2009-01-01

    textabstractThe three different areas and the examples have illustrated several catalytic functions of standards for innovation. First, the standardisation process reduces the time to market of inventions, research results and innovative technologies. Second, standards themselves promote the diffusi

  17. Application of a Natural Gas Fired Hot Blast Stove in Drying Industry%天然气热风炉在干燥行业中的节能应用

    Institute of Scientific and Technical Information of China (English)

    张丽丽; 姜谋

    2012-01-01

    An application of a natural gas fired hot blast stove in drying industry is introduced. Using natural gas fired hot blast stove instead of vapor heat exchanger, thermal efficiency of drying industry is improved significantly, and remarkable energy -saving effect is obtained. According to the retrofitting practice of drying system in a biopharmacy corporation, satisfactory results were obtained. After the retrofitting, the temperature of drying -medium can exceed 180℃ , and maintain stable, which improve production by 20%. The temperature of drying - medium can adjusted automatically according to moisture content of biomass feed, so drying quality can be guaranteed. The thermal efficiency of drying system is increased from 44% to above 96%.%介绍了天然气直燃热风炉在干燥行业的节能应用.采用天然气直燃热风炉代替蒸汽换热装置,可大幅提高干燥系统的热效率,节能效果显著.通过对某生物制药公司干燥系统的改造实践,取得了比较满意的改造效果.改造后,干燥介质温度可达到180℃以上,出力稳定,使设备生产能力提高20%.另外,干燥介质的温度可以根据生物质饲料所含水分自动调节,确保了干燥品质.系统热效率由改造前的44%提高到96%以上.

  18. Hot and Dry Cleaning of Biomass-Gasified Gas Using Activated Carbons with Simultaneous Removal of Tar, Particles, and Sulfur Compounds

    Directory of Open Access Journals (Sweden)

    Kinya Sakanishi

    2012-05-01

    Full Text Available This study proposes a gas-cleaning process for the simultaneous removal of sulfur compounds, tar, and particles from biomass-gasified gas using Fe-supported activated carbon and a water-gas shift reaction. On a laboratory scale, the simultaneous removal of H2S and COS was performed under a mixture of gases (H2/CO/CO2/CH4/C2H4/N2/H2S/COS/steam. The reactions such as COS + H2 → H2S + CO and COS + H2O → H2S + CO2 and the water-gas shift reaction were promoted on the Fe-supported activated carbon. The adsorption capacity with steam was higher than that without steam. On a bench scale, the removal of impurities from a gas derived from biomass gasification was investigated using two activated filters packed with Fe-supported activated carbon. H2S and COS, three- and four-ring polycyclic aromatic hydrocarbons (PAHs, and particles were removed and a water-gas shift reaction was promoted through the first filter at 320–350 °C. The concentrations of H2S and COS decreased to less than 0.1 ppmv. Particles and the one- and two-ring PAHs, except for benzene, were then removed through the second filter at 60–170 °C. The concentration of tar and particles decreased from 2428 to 102 mg Nm−3 and from 2244 to 181 mg Nm−3, respectively.

  19. Detection and characterization of small hot fires: Comparing FireBird, BIRD, S-NPP VIIRS and MODIS capacities over gas flares

    Science.gov (United States)

    Ruecker, Gernot; Schroeder, Wilfrid; Lorenz, Eckehard; Kaiser, Johannes; Caseiro, Alexandre

    2016-04-01

    According to recent research, black carbon has the second strongest effect on the earth climate system after carbon dioxide. In high Northern latitudes, industrial gas flares are an important source of black carbon, especially in winter. This fact is particularly relevant for the relatively fast observed climate change in the Arctic since deposition of black carbon changes the albedo of snow and ice, thus leading to a positive feedback cycle. Here we explore gas flare detection and Fire Radiative Power (FRP) retrievals of the German FireBird TET-1 and BIRD Hotspot Recognition Systems (HSRS), the VIIRS sensor on board of the S-NPP satellite, and the MODIS sensor using temporally close to near coincident data acquisitions. Comparison is based on level 2 products developed for fire detection for the different sensors; in the case of S-NPP VIIRS we use two products: the new VIIRS 750m algorithm based on MODIS collection 6, and the 350 m algorithm based on the VIIRS mid-infrared I (Imaging) band, which offers high resolution, but no FRP retrievals. Results indicate that the highest resolution FireBird sensors offer the best detection capacities, though the level two product shows false alarms, followed by the VIIRS 350 m and 750 m algorithms. MODIS has the lowest detection rate. Preliminary results of FRP retrievals show that FireBird and VIIRS algorithms have a good agreement. Given the fact that most gas flaring is at the detection limit for medium to coarse resolution space borne sensors - and hence measurement errors may be high - our results indicates that a quantitative evaluation of gas flaring using these sensors is feasible. Results shall be used to develop a gas flare detection algorithm for Sentinel-3, and a similar methodology will be employed to validate the capacity of Sentinel 3 to detect and characterize small high temperature sources such as gas flares.

  20. Gas doping ratio effects on p-type hydrogenated nanocrystalline silicon thin films grown by hot-wire chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Luo, P.Q. [Solar Energy Institute, Department of Physics, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)], E-mail: robt@sjtu.edu.cn; Zhou, Z.B. [Solar Energy Institute, Department of Physics, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)], E-mail: zbzhou@sjtu.edu.cn; Chan, K.Y. [Thin Film Laboratory, Faculty of Engineering, Multimedia University, Jalan Multimedia, Cyberjaya 63100, Selangor (Malaysia); Tang, D.Y.; Cui, R.Q.; Dou, X.M. [Solar Energy Institute, Department of Physics, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)

    2008-12-30

    Hydrogenated nanocrystalline silicon (nc-Si:H) grown by hot-wire chemical vapor deposition (HWCVD) has recently drawn significant attention in the area of thin-film large area optoelectronics due to possibility of high deposition rate. We report on the effects of diborane (B{sub 2}H{sub 6}) doping ratio on the microstructural and optoelectrical properties of the p-type nc-Si:H thin films grown by HWCVD at low substrate temperature of 200 deg. C and with high hydrogen dilution ratio of 98.8%. An attempt has been made to elucidate the boron doping mechanism of the p-type nc-Si:H thin films deposited by HWCVD and the correlation between the B{sub 2}H{sub 6} doping ratio, crystalline volume fraction, optical band gap and dark conductivity.

  1. Catalytic ignition of light hydrocarbons

    Institute of Scientific and Technical Information of China (English)

    K. L. Hohn; C.-C. Huang; C. Cao

    2009-01-01

    Catalytic ignition refers to phenomenon where sufficient energy is released from a catalytic reaction to maintain further reaction without additional extemai heating. This phenomenon is important in the development of catalytic combustion and catalytic partial oxidation processes, both of which have received extensive attention in recent years. In addition, catalytic ignition studies provide experimental data which can be used to test theoretical hydrocarbon oxidation models. For these reasons, catalytic ignition has been frequently studied. This review summarizes the experimental methods used to study catalytic ignition of light hydrocarbons and describes the experimental and theoretical results obtained related to catalytic ignition. The role of catalyst metal, fuel and fuel concentration, and catalyst state in catalytic ignition are examined, and some conclusions are drawn on the mechanism of catalytic ignition.

  2. Warm gas phase chemistry as possible origin of high HDO/H2O ratios in hot and dense gases: application to inner protoplanetary discs

    CERN Document Server

    Thi, Wing-Fai; Kamp, Inga

    2009-01-01

    The origin of Earth oceans is controversial. Earth could have acquired its water either from hydrated silicates (wet Earth scenario) or from comets (dry Earth scenario). [HDO]/[H2O] ratios are used to discriminate between the scenarios. High [HDO]/[H2O] ratios are found in Earth oceans. These high ratios are often attributed to the release of deuterium enriched cometary water ice, which was formed at low gas and dust temperatures. Observations do not show high [HDO]/[H2O] in interstellar ices. We investigate the possible formation of high [HDO]/[H2O] ratios in dense (nH> 1E6 cm^{-3}) and warm gas (T=100-1000 K) by gas-phase photochemistry in the absence of grain surface chemistry. We derive analytical solutions, taking into account the major neutral-neutral reactions for gases at T>100 K. The chemical network is dominated by photodissociation and neutral-neutral reactions. Despite the high gas temperature, deuterium fractionation occurs because of the difference in activation energy between deuteration enrich...

  3. Performance characterization of a hydrogen catalytic heater.

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Terry Alan; Kanouff, Michael P.

    2010-04-01

    This report describes the performance of a high efficiency, compact heater that uses the catalytic oxidation of hydrogen to provide heat to the GM Hydrogen Storage Demonstration System. The heater was designed to transfer up to 30 kW of heat from the catalytic reaction to a circulating heat transfer fluid. The fluid then transfers the heat to one or more of the four hydrogen storage modules that make up the Demonstration System to drive off the chemically bound hydrogen. The heater consists of three main parts: (1) the reactor, (2) the gas heat recuperator, and (3) oil and gas flow distribution manifolds. The reactor and recuperator are integrated, compact, finned-plate heat exchangers to maximize heat transfer efficiency and minimize mass and volume. Detailed, three-dimensional, multi-physics computational models were used to design and optimize the system. At full power the heater was able to catalytically combust a 10% hydrogen/air mixture flowing at over 80 cubic feet per minute and transfer 30 kW of heat to a 30 gallon per minute flow of oil over a temperature range from 100 C to 220 C. The total efficiency of the catalytic heater, defined as the heat transferred to the oil divided by the inlet hydrogen chemical energy, was characterized and methods for improvement were investigated.

  4. 催化干气回收乙烯装置中脱碳塔内件形式优化改造%Optimal Modification of Internals in Decarbonization Column of Catalytic Dry Gas Ethylene Recovery Unit

    Institute of Scientific and Technical Information of China (English)

    刘玉花

    2016-01-01

    脱碳塔是影响催化干气回收乙烯装置处理量的瓶颈。装置低负荷运行时脱碳塔操作平稳,而负荷升高时塔顶部分液罐中液位升高,操作不正常,净化气带胺液跑损严重。分析了脱碳塔的特殊性,结合现场操作存在问题,选用消泡型内件及填料对脱碳塔进行改造,改造后装置操作弹性增加,处理能力提高,脱碳塔胺液夹带现象明显降低,胺液补充量显著减少,经济效益显著,可为类似系统内件改造提供借鉴。%Decarbonization column is the bottleneck which affecting the capacity of the catalytic dry gas ethylene recovery unit.When the unit operating in low load,the decarbonization column under steady state.However,when the operation load increase,the liquid level of the liquid sep-arate pot will rise and the operation state gets bad.The particularity of decarbonization column is analyzed and combined with the problems encountered in actual operating situation,and the opti-mal modification of the internals in decarbonization column is put forward.Through selecting the defoaming internals and modifying,the flexibility of the operation and the capacity of the unit is increased.Moreover,the amine liquid consumption is decreased obviously and the economic bene-fit is remarkable.An important reference for the similar device is provided.

  5. Catalytic conversion of light alkanes

    Energy Technology Data Exchange (ETDEWEB)

    Lyons, J.E.

    1992-06-30

    The second Quarterly Report of 1992 on the Catalytic Conversion of Light Alkanes reviews the work done between April 1, 1992 and June 31, 1992 on the Cooperative Agreement. The mission of this work is to devise a new catalyst which can be used in a simple economic process to convert the light alkanes in natural gas to oxygenate products that can either be used as clean-burning, high octane liquid fuels, as fuel components or as precursors to liquid hydrocarbon uwspomdon fuel. During the past quarter we have continued to design, prepare, characterize and test novel catalysts for the mild selective reaction of light hydrocarbons with air or oxygen to produce alcohols directly. These catalysts are designed to form active metal oxo (MO) species and to be uniquely active for the homolytic cleavage of the carbon-hydrogen bonds in light alkanes producing intermediates which can form alcohols. We continue to investigate three molecular environments for the active catalytic species that we are trying to generate: electron-deficient macrocycles (PHASE I), polyoxometallates (PHASE II), and regular oxidic lattices including zeolites and related structures as well as other molecular surface structures having metal oxo groups (PHASE I).

  6. DEVELOPMENT OF HIGH ACTIVITY, CATALYTIC SYSTEMS FOR NOx REDUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2001-12-01

    This project was directed at an investigation of catalytic NO{sub x} reduction on carbonaceous supports at low temperatures. The experimental work was conducted primarily in a packed bed reactor/gas flow system that was constructed for this work. The analytical techniques employed were mass spectrometry, NO{sub x} chemiluminescence, and gas chromatography. The experimental plan was focused on steady-state reactivity experiments, followed by temperature programmed desorption (TPD) of surface intermediates, and also selected temperature-programmed reaction (TPR) experiments. Both uncatalyzed and catalyzed (potassium-promoted) phenolic resin char, were investigated as well as the catalytic effect of additional CO in the gas phase.

  7. Design parameters for measurements of local catalytic activity on surfaces

    DEFF Research Database (Denmark)

    Johansson, Martin; Johannessen, Tue; Jørgensen, Jan Hoffmann;

    2006-01-01

    Computational fluid dynamics in combination with experiments is used to characterize a gas sampling device for measurements of the local catalytic activity on surfaces. The device basically consists of a quartz capillary mounted concentrically inside an aluminum tube. Reactant gas is blown toward...

  8. Catalytic coherence transformations

    Science.gov (United States)

    Bu, Kaifeng; Singh, Uttam; Wu, Junde

    2016-04-01

    Catalytic coherence transformations allow the otherwise impossible state transformations using only incoherent operations with the aid of an auxiliary system with finite coherence that is not being consumed in any way. Here we find the necessary and sufficient conditions for the deterministic and stochastic catalytic coherence transformations between a pair of pure quantum states. In particular, we show that the simultaneous decrease of a family of Rényi entropies of the diagonal parts of the states under consideration is a necessary and sufficient condition for the deterministic catalytic coherence transformations. Similarly, for stochastic catalytic coherence transformations we find the necessary and sufficient conditions for achieving a higher optimal probability of conversion. We thus completely characterize the coherence transformations among pure quantum states under incoherent operations. We give numerous examples to elaborate our results. We also explore the possibility of the same system acting as a catalyst for itself and find that indeed self-catalysis is possible. Further, for the cases where no catalytic coherence transformation is possible we provide entanglement-assisted coherence transformations and find the necessary and sufficient conditions for such transformations.

  9. Herschel observations of Extra-Ordinary Sources: H2S as a Probe of Dense Gas and Possibly Hidden Luminosity Toward the Orion KL Hot Core

    CERN Document Server

    Crockett, N R; Neill, J L; Black, J H; Blake, G A; Kleshcheva, M

    2014-01-01

    We present Herschel/HIFI observations of the light hydride H$_{2}$S obtained from the full spectral scan of the Orion Kleinmann-Low nebula (Orion KL) taken as part of the HEXOS GT key program. In total, we observe 52, 24, and 8 unblended or slightly blended features from H$_{2}$$^{32}$S, H$_{2}$$^{34}$S, and H$_{2}$$^{33}$S, respectively. We only analyze emission from the so called hot core, but emission from the plateau, extended ridge, and/or compact ridge are also detected. Rotation diagrams for ortho and para H$_{2}$S follow straight lines given the uncertainties and yield T$_{\\rm rot}$=141$\\pm$12 K. This indicates H$_{2}$S is in LTE and is well characterized by a single kinetic temperature or an intense far-IR radiation field is redistributing the population to produce the observed trend. We argue the latter scenario is more probable and find that the most highly excited states (E$_{\\rm up}$>1000 K) are likely populated primarily by radiation pumping. We derive an H$_{2}$$^{32}$S column density, N$_{\\rm ...

  10. High resolution Chandra HETG and RXTE observations of GRS 1915+105 A hot disk atmosphere & cold gas enriched in Iron and Silicon

    CERN Document Server

    Lee, J C; Schulz, N S; Remillard, R A; Blackman, E G; Fabian, A C

    2001-01-01

    The time-averaged 30 ks Chandra HETGS observation of the micro-quasar GRS 1915+105 in the low hard state reveals for the first time in this source neutral K absorption edges from Fe, Si, Mg, & S. Ionized resonance absorption from H-, and He-like Fe (XXV, XXVI), Ca XX and possibly emission from neutral Fe Kalpha and ionized Fe XXV (forbidden, or the resonance emission component of a P-Cygni profile) are also seen. We report the tentative detection of the first astrophysical signature of XAFS in the photoelectric edge of Si (and possibly Fe and Mg), attributed to material in grains. The large column densities measured from the neutral edges reveal anomalous Si and Fe abundances. Scenarios for which the anomalous abundances can be attributed to surrounding cold material associated with GRS 1915+105 and/or that the enrichment may signify either a highly unusual supernova/hypernova, or external supernova activity local to the binary are discussed. We attribute the ionized features to a hot disk, disk-wind, or ...

  11. Large-scale time-resolved digital particle image velocimetry (TR-DPIV) for measurement of high subsonic hot coaxial jet exhaust of a gas turbine engine

    International Nuclear Information System (INIS)

    The development of a highly configurable triple digital particle image velocimetry (DPIV) system is described, which is capable of acquiring both continuous, statistically independent measurements at up to 14 Hz and time-resolved PIV data at MHz rates. The system was used at QinetiQ's Noise Test Facility (NTF) as part of the EU-funded CoJeN programme to obtain measurements from high subsonic (Mach ≤ 0.9), hot (∼500 °C), large (1/10th) scale coaxial jet flows at a standoff distance of ∼1 m. High-resolution time-averaged velocity and turbulence data were obtained for complete coaxial engine exhaust plumes down to 4 m (20 jet diameters) from the nozzle exit in less than 1 h. In addition, the system allowed volumetric data to be obtained, enabling fast assessment of spatial alignment of nozzle configurations. Furthermore, novel six-frame time-series data-capture is demonstrated up to 330 kHz, used to calculate time–space correlations within the exhaust, allowing for study of spatio-temporal developments in the jet, associated with jet-noise production. The highly automated system provides synchronization triggers for simultaneous acquisition from different measurement systems (e.g. LDA) and is shown to be versatile, rugged, reliable and portable, operating remotely in a hostile environment. Data are presented for three operating conditions and two nozzle geometries, providing a database to be used to validate CFD models of coaxial jet flow

  12. Catalytic extraction processing of contaminated scrap metal

    International Nuclear Information System (INIS)

    Molten Metal Technology was awarded a contract to demonstrate the applicability of the Catalytic Extraction Process, a proprietary process that could be applied to US DOE's inventory of low level mixed waste. This paper is a description of that technology, and included within this document are discussions of: (1) Program objectives, (2) Overall technology review, (3) Organic feed conversion to synthetic gas, (4) Metal, halogen, and transuranic recovery, (5) Demonstrations, (6) Design of the prototype facility, and (7) Results

  13. Selective Catalytic Reduction of NO with Methane

    Institute of Scientific and Technical Information of China (English)

    Xiang Gao; Qi Yu; Limin Chen

    2003-01-01

    The removal of nitrogen oxides from exhaust gases has attracted great attention in recent years, and many approaches have been developed depending on the application. Methane, the main component of natural gas, has great potential as a NO reductant. In this paper, a number of catalysts previous reported for this catalytic reduction of NO have been reviewed, including a direct comparison of the relative activities and effective factors of the catalysts. Reaction mechanisms have also been explored preliminarily.

  14. Thermal reliability and performance improvement of close-coupled catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Hijikata, Toshihiko; Kurachi, Hiroshi; Katsube, Fumio [NGK Insulators, Ltd., Nagoya (Japan); Honacker, H. van

    1996-09-01

    This paper proposes a high temperature catalytic converter design using a ceramic substrate and intumescent matting. It also describes the improvement of converter performance using an advanced thin wall ceramic substrate. Due to future tightening of emission regulations and improvement of fuel economy, higher exhaust gas temperatures are suggested. Therefore, reduction of thermal reliability of an intumescent mat will be a concern because the catalytic converter will be exposed to high temperatures. For this reason, a new design converter has been developed using a dual cone structure for both the inlet and outlet cones. This minimizes heat conduction through the cone and decreases the temperature affecting the mat area. This design converter, without the use of a heat-shield, reduces the converter surface temperature to 441 C despite a catalyst bed temperature of 1,050 C. The long term durability of the converter is demonstrated by the hot vibration test. Since the new design converter does not need a heat-shield, the catalyst diameter can be enlarged by the width of the air gap used in the current design converter. By using an advanced thin wall ceramic substrate, such as 0.11 mm/620 kcpsm (4 mil/400 cpsi), it is possible to improve emission performance and pressure drop compared with the conventional 0.16 mm/620 kcpsm (6 mil/400 cpsi) ceramic substrate.

  15. Development of Catalytic Cooking Plates

    Energy Technology Data Exchange (ETDEWEB)

    Hjelm, Anna-Karin; Silversand, Fredrik [CATATOR AB, Lund (Sweden); Tena, Emmanuel; Berger, Marc [Gaz de France (France)

    2004-04-01

    Gas catalytic combustion for gas stoves or cooking plates (closed catalytic burner system with ceramic plates) is a very promising technique in terms of ease of cleaning, power modulation and emissions. Previous investigations show that wire mesh catalysts, prepared and supplied by Catator AB (CAT), seem to be very well suited for such applications. Beside significantly reducing the NOx-emissions, these catalysts offer important advantages such as good design flexibility, low pressure drop and high heat transfer capacity, where the latter leads to a quick thermal response. Prior to this project, Gaz de France (GdF) made a series of measurements with CAT's wire mesh catalysts in their gas cooking plates and compared the measured performance with similar results obtained with theirs cordierite monolith catalysts. Compared to the monolith catalyst, the wire mesh catalyst was found to enable very promising results with respect to both emission levels (<10 mg NO{sub x} /kWh, <5 mg CO/kWh) and life-time (>8000 h vs. 700 h at 200 kW/m{sup 2}). It was however established that the radiation and hence, the thermal efficiency of the cooking plate, was significantly less than is usually measured in combination with the monolith (15 % vs. 32 %). It was believed that the latter could be improved by developing new burner designs based on CAT's wire mesh concept. As a consequence, a collaboration project between GdF, CAT and the Swedish Gas Technology AB was created. This study reports on the design, the construction and the evaluation of new catalytic burners, based on CAT's wire mesh catalysts, used for the combustion of natural gas in gas cooking stoves. The evaluation of the burners was performed with respect to key factors such as thermal efficiency, emission quality and pressure drop, etc, by the use of theoretical simulations and experimental tests. Impacts of parameters such as the the wire mesh number, the wire mesh structure (planar or folded), the

  16. Hot Topics in Study and Application of Steel Line Pipe for Natural Gas Transportation%天然气输送钢管研究与应用中的几个热点问题

    Institute of Scientific and Technical Information of China (English)

    李鹤林

    2001-01-01

    Several hot topics in study and application of steel line pipefor natural gas transportation are introduced including transportation under high pressure ,research and development of high grade steel line pipe,line pipe with high HIC(Hydrogen Induced Cracking) resistant and its technical requirements,rich gas transportation and technical requirements of steel pipe,comparison and selection between longitudinally submerged arc welded pipe and spirally submerged arc welded pipe,ductile fracture arrest of steel pipe for gas transportation,SCC (Stress Corrosion Cracking) of pipeline in soil environment with approximately neutral pH value,residual stress and its control of line pipe,the ratio of yield to tensile strength of high strength steel line pipe,fitness-for-purpose assessment and risk management of pipeline in service,etc..%全面阐述了天然气输送钢管研究与应用中的热点问题:高压输送与高钢级管线钢的研究开发;抗HIC管线管及其技术条件;富气输送及其对钢管性能的要求;直缝埋弧焊管和螺旋缝埋弧焊管的比较与选择;输气钢管延性断裂的止裂;管线在近中性pH土壤环境中的应力腐蚀开裂;管线管的残余应力及控制;高强度管线钢的屈强比问题;在役管道的适用性评价及风险管理等。

  17. Tritium stripping by a catalytic exchange stripper

    International Nuclear Information System (INIS)

    A catalytic exchange process for stripping elemental tritium from gas streams has been demonstrated. The process uses a catalyzed isotopic exchange reaction between tritium in the gas phase and protium or deuterium in the solid phase on alumina. The reaction is catalyzed by platinum deposited on the alumina. The process has been tested with both tritium and deuterium. Decontamination factors (ration of inlet and outlet tritium concentrations) as high as 1000 have been achieved, depending on inlet concentration. The test results and some demonstrated applications are presented

  18. The ionized and hot gas in M17 SW: SOFIA/GREAT THz observations of [C II] and 12CO J=13-12

    CERN Document Server

    Perez-Beaupuits, J P; Ossenkopf, V; Stutzki, J; Guesten, R; Simon, R; Huebers, H -W; Ricken, O; Sandell, G

    2012-01-01

    With new THz maps that cover an area of ~3.3x2.1 pc^2 we probe the spatial distribution and association of the ionized, neutral and molecular gas components in the M17 SW nebula. We used the dual band receiver GREAT on board the SOFIA airborne telescope to obtain a 5'.7x3'.7 map of the 12CO J=13-12 transition and the [C II] 158 um fine-structure line in M17 SW and compare the spectroscopically resolved maps with corresponding ground-based data for low- and mid-J CO and [C I] emission. For the first time SOFIA/GREAT allow us to compare velocity-resolved [C II] emission maps with molecular tracers. We see a large part of the [C II] emission, both spatially and in velocity, that is completely non-associated with the other tracers of photon-dominated regions (PDR). Only particular narrow channel maps of the velocity-resolved [C II] spectra show a correlation between the different gas components, which is not seen at all in the integrated intensity maps. These show different morphology in all lines but give hardly...

  19. Resolution-independent modelling of environmental effects in semi-analytic models of galaxy formation that include ram-pressure stripping of both hot and cold gas

    Science.gov (United States)

    Luo, Yu; Kang, Xi; Kauffmann, Guinevere; Fu, Jian

    2016-05-01

    The quenching of star formation in satellite galaxies is observed over a wide range of dark matter halo masses and galaxy environments. In the recent Guo et al. and Fu et al. semi-analytic + N-body models, the gaseous environment of the satellite galaxy is governed by the properties of the dark matter subhalo in which it resides. This quantity depends of the resolution of the N-body simulation, leading to a divergent fraction of quenched satellites in high- and low-resolution simulations. Here, we incorporate an analytic model to trace the subhaloes below the resolution limit. We demonstrate that we then obtain better converged results between the Millennium I and II simulations, especially for the satellites in the massive haloes (log Mhalo = [14, 15]). We also include a new physical model for the ram-pressure stripping of cold gas in satellite galaxies. However, we find very clear discrepancies with observed trends in quenched satellite galaxy fractions as a function of stellar mass at fixed halo mass. At fixed halo mass, the quenched fraction of satellites does not depend on stellar mass in the models, but increases strongly with mass in the data. In addition to the overprediction of low-mass passive satellites, the models also predict too few quenched central galaxies with low stellar masses, so the problems in reproducing quenched fractions are not purely of environmental origin. Further improvements to the treatment of the gas-physical processes regulating the star formation histories of galaxies are clearly necessary to resolve these problems.

  20. Catalytic Conversion of Biofuels

    DEFF Research Database (Denmark)

    Jørgensen, Betina

    This thesis describes the catalytic conversion of bioethanol into higher value chemicals. The motivation has been the unavoidable coming depletion of the fossil resources. The thesis is focused on two ways of utilising ethanol; the steam reforming of ethanol to form hydrogen and the partial oxida...