WorldWideScience

Sample records for h2 gas mixtures

  1. Modeling Phase Equilibria for Acid Gas Mixtures Using the CPA Equation of State. I. Mixtures with H2S

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Kontogeorgis, Georgios; Michelsen, Michael Locht

    2010-01-01

    The Cubic-Plus-Association (CPA) equation of state is applied to a large variety of mixtures containing H2S, which are of interest in the oil and gas industry. Binary H2S mixtures with alkanes, CO2, water, methanol, and glycols are first considered. The interactions of H2S with polar compounds...... (water, methanol, and glycols) are modeled assuming presence or not of cross-association interactions. Such interactions are accounted for using either a combining rule or a cross-solvation energy obtained from spectroscopic data. Using the parameters obtained from the binary systems, one ternary...

  2. Corrosion of 310 stainless steel in H2-H2O-H2S gas mixtures: Studies at constant temperature and fixed oxygen potential

    Science.gov (United States)

    Rao, D. B.; Jacob, K. T.; Nelson, H. G.

    1981-01-01

    Corrosion of SAE 310 stainless steel in H2-H2O-H2S gas mixtures was studied at a constant temperature of 1150 K. Reactive gas mixtures were chosen to yield a constant oxygen potential of approximately 6 x 10 to the minus 13th power/cu Nm and sulfur potentials ranging from 0.19 x 10 to the minus 2nd power/cu Nm to 33 x 10 to the minus 2nd power/cu Nm. The kinetics of corrosion were determined using a thermobalance, and the scales were analyzed using metallography, scanning electron microscopy, and energy dispersive X-ray analysis. Two corrosion regimes, which were dependent on sulfur potential, were identified. At high sulfur potentials (p sub S sub 2 less than or equal to 2.7 x 10 to the minus 2nd power/cu Nm) the corrosion rates were high, the kinetics obeyed a linear rate equation, and the scales consisted mainly of sulfide phases similar to those observed from pure sulfication. At low sulfur potentials (P sub S sub 2 less than or equal to 0.19 x 10 to the minus 2nd power/cu Nm) the corrosion rates were low, the kinetics obeyed a parabolic rate equation, and scales consisted mainly of oxide phases.

  3. Optical Characterization of Diamond Synthesis Using CH3OH-H2 Gas Mixtures

    Institute of Scientific and Technical Information of China (English)

    Man Weidong; Wang Jianhua; Li Lei; Zhang Baohua; Bai Yuming

    2005-01-01

    Diamond films with high infrared transmittance have been successfully deposited using CH3OH-H2 gas mixtures through microwave plasma enhanced chemical vapor deposition (MWCVD). The primary purpose of this study is to determine the effect of the deposition conditions on the optical properties of MWCVD diamond films using CH3OH-H2 gas mixtures. Room temperature optical properties of freestanding diamond films were studied by Fourier transform IR spectroscopy. Experimental results indicated that under appropriate deposition temperature (620 ℃) and methanol concentration (5.7%), the refractive index of CVD diamond films (2.33)was comparable with that of natural diamond (2.417). The average infrared transmittance was above 65% in the middle infrared region (500 cm-1 ~ 4000 cm-1), approaching to the theoretical value of diamond (71.4%). The mechanism of growing high IR transmittance diamond films by utilizing CH3OH-H2 gas system is that the high methanol concentration used in this study makes the surface roughness of diamond films decreased by increasing the secondary nucleation density and the high O/C ratio in CH3OH-H2 gas system, improved the quality of diamond films and therefore decreased the absorption of non-diamond carbon in the films.

  4. Study of DC Circuit Breaker of H2-N2 Mixture Gas for High Voltage

    Science.gov (United States)

    Shiba, Yuji; Morishita, Yukinaga; Kaneko, Shuhei; Okabe, Shigemitsu; Mizoguchi, Hitoshi; Yanabu, Satoru

    Global warming caused by CO2 etc. is a field where the concern is very high. Especially, automobile emissions are problem for it. Therefore, the hybrid car is widely development and used recently. Hybrid car used electric power and gasoline. So, the car reduces CO2. Hybrid car has engine and motor. To rotate the motor, hybrid car has battery. This battery is large capacity. Therefore, the relay should interrupt high DC current for the switch of the motor and the engine. So, hybrid car used hydrogen gas filling relay We studied interruption test for the research of a basic characteristic of hydrogen gas. DC current has not current zero point. So, it is necessary to make the current zero by high arc voltage and forcible current zero point. The loss coefficient and arc voltage of hydrogen is high. Therefore, we studied interruption test for used high arc voltage. We studied interruption test and dielectric breakdown test of air, pure Hydrogen, and Hydrogen- nitrogen mixture gas. As a result, we realized H2-N2(80%-20%) is the best gas.

  5. Explosive limits and its container factors of polybasic explosive mixture gas containing H2, CH4 and CO

    Institute of Scientific and Technical Information of China (English)

    胡耀元; 李勇; 朱凯汉; 周邦智; 杨元法

    2002-01-01

    Explosive characteristics of polybasic explosive mixture gas are systematically researched. Over 28000 experimental data have been obtained from 1278 effective experiments. The paper probes into the concentration explosive limits and the container factors of polybasic explosive mixture gas which contains H2, CH4 and CO. It has worked out the sufficient and necessary condition for branch-chain explosion and the unified expression of the probability of the heterogeneous chain termination. Experiments indicate that the concentration explosive limits of polybasic explosive mixture gas (H2, CH4, CO) relate to many factors. They enlarge with the augmentability of the container (linear size, geometric shape, and flame spread direction). This will be of great significance to guiding the revision of related industrial safety targets, reclaiming and reusing related industrial tail gas and waste gas, taking precautions against the explosion hazard of mixture gas in correlated industry and mines, and applying the br

  6. Reaction mechanism for the thermal decomposition of BCl3/CH4/H2 gas mixtures.

    Science.gov (United States)

    Reinisch, Guillaume; Vignoles, Gérard L; Leyssale, Jean-Marc

    2011-10-27

    This paper presents an ab initio study of the B/C/Cl/H gas phase mechanism, featuring 10 addition-elimination reactions involving BH(i)Cl(j) (i + j ≤ 3) species and a first description of the chemical interaction between the carbon-containing and boron-containing subsystems through the three reactions BCl(3) + CH(4) ⇌ BCl(2)CH(3) + HCl, BHCl(2) + CH(4) ⇌ BCl(2)CH(3) + H(2), and BCl(2) + CH(4) ⇌ BHCl(2) + CH(3). A reaction mechanism is then proposed and used to perform some illustrative equilibrium and kinetic calculations in the context of chemical vapor deposition (CVD) of boron carbide. Our results show that the new addition-elimination reaction paths play a crucial role by lowering considerably the activation barrier with respect to previous theoretical evaluations; they also confirm that BCl(2)CH(3) is an important species in the mechanism.

  7. Modelling the kinetics of a copper vapour laser with H_2-HCl-Ne buffer gas mixtures

    Science.gov (United States)

    Carman, R. J.; Withford, M. J.; Brown, D. J. W.; Piper, J. A.

    1998-10-01

    Following our investigations into the influence of halogens and halogen donor buffer gas additives in high temperature or "elemental" copper vapour lasers, a new sub-class of laser has recently been developed in our laboratory based on H_2-HCl-Ne buffer gas mixtures. This device, known as a kinetically enhanced copper vapour laser (KE-CVL) [1], typically produces laser output powers 2-3 times higher than from a similar sized elemental copper laser employing a standard H_2-Ne buffer gas mix, and at significantly higher wallplug efficiencies. A computer model has been used to simulate the discharge kinetics in a 38mm bore KE-CVL which typically produced 80-100W in the laboratory at pulse repetition frequencies of 4-6kHz. The model is based on a rate-equation analysis of the spatio-temporal evolution of selected atomic, ionic and molecular species population densities, taking into account multiple excitation/afterglow cycles to achieve temporal self-consistency. The halogen donor species HCl(v=0,1), Cl_2, Cl, and Cl^- and associated collision processes have been included in the kinetics scheme for the KE-CVL in addition to the 25 species representing the Cu-Ne-H2 mixture to investigate their influence on the plasma kinetics during the excitation and afterglow periods. [1] M.J. Withford, D.J.W. Brown, R.J.Carman and J.A. Piper, Opt.Lett., 23, 706-708, (1998).

  8. Reduction Kinetics of Wüstite Scale on Pure Iron and Steel Sheets in Ar and H2 Gas Mixture

    Science.gov (United States)

    Mao, Weichen; Sloof, Willem G.

    2017-07-01

    A dense and closed Wüstite scale is formed on pure iron and Mn alloyed steel after oxidation in Ar + 33 vol pct CO2 + 17 vol pct CO gas mixture. Reducing the Wüstite scale in Ar + H2 gas mixture forms a dense and uniform iron layer on top of the remaining Wüstite scale, which separates the unreduced scale from the gas mixture. The reduction of Wüstite is controlled by the bulk diffusion of dissolved oxygen in the formed iron layer and follows parabolic growth rate law. The reduction kinetics of Wüstite formed on pure iron and on Mn alloyed steel are the same. The parabolic rate constant of Wüstite reduction obeys an Arrhenius relation with an activation energy of 104 kJ/mol if the formed iron layer is in the ferrite phase. However, at 1223 K (950 °C) the parabolic rate constant of Wüstite reduction drops due to the phase transformation of the iron layer from ferrite to austenite. The effect of oxygen partial pressure on the parabolic rate constant of Wüstite reduction is negligible when reducing in a gas mixture with a dew point below 283 K (10 °C). During oxidation of the Mn alloyed steel, Mn is dissolved in the Wüstite scale. Subsequently, during reduction of the Wüstite layer, Mn diffuses into the unreduced Wüstite. Ultimately, an oxide-free iron layer is obtained at the surface of the Mn alloyed steel, which is beneficial for coating application.

  9. Reduction mechanism of high-chromium vanadium-titanium magnetite pellets by H2-CO-CO2 gas mixtures

    Science.gov (United States)

    Tang, Jue; Chu, Man-sheng; Li, Feng; Tang, Ya-ting; Liu, Zheng-gen; Xue, Xiang-xin

    2015-06-01

    The reduction of high-chromium vanadium-titanium magnetite as a typical titanomagnetite containing 0.95wt% V2O5 and 0.61wt% Cr2O3 by H2-CO-CO2 gas mixtures was investigated from 1223 to 1373 K. Both the reduction degree and reduction rate increase with increasing temperature and increasing hydrogen content. At a temperature of 1373 K, an H2/CO ratio of 5/2 by volume, and a reduction time of 40 min, the degree of reduction reaches 95%. The phase transformation during reduction is hypothesized to proceed as follows: Fe2O3 → Fe3O4 → FeO → Fe; Fe9TiO15 + Fe2Ti3O9 → Fe2.75Ti0.25O4 → FeTiO3 → TiO2; (Cr0.15V0.85)2O3 → Fe2VO4; and Cr1.3Fe0.7O3 → FeCr2O4. The reduction is controlled by the mixed internal diffusion and interfacial reaction at the initial stage; however, the interfacial reaction is dominant. As the reduction proceeds, the internal diffusion becomes the controlling step.

  10. Monitoring of CO2/H2S gas mixture injection in basaltic rocks at Hellisheiði Geothermal Power Plant, Iceland

    Science.gov (United States)

    Clark, Deirdre E.; Gunnarsson, Ingvi; Aradóttir, Edda S.; Gunnlaugsson, Einar; Júlíusson, Bjarni M.; Matter, Juerg M.; Stute, Martin; Oelkers, Eric H.; Snæbjörnsdóttir, Sandra Ó.; Gíslason, Sigurður R.

    2016-04-01

    Hellisheiði geothermal power plant emits about 41,000 tonnes of CO2 and 10,000 tonnes of H2S per year as a by-product of geothermal energy production. Icelandic regulations, stricter than WHO guidelines, have been in effect in order to reduce H2S emissions of the geothermal industry, while carbon capture and storage (CCS) is one method recommended to minimise the amount of CO2 released into the atmosphere. The overall cost of CCS is dominated by that of capture and gas separation. This capture cost could be lowered by injecting gas mixtures into rocks as is now being tested at Hellisheiði geothermal power plant in SW-Iceland. There, a gas mixture of 60% CO2 and 40% H2S is dissolved in water from the plant and injected into the basaltic rocks. The CarbFix and SulFix pilot projects demonstrated solubility storage of the pure separate gases in a few minutes [1,2] and that more than 80% of the injected CO2 into basaltic rocks was mineralised within a year from its injection at 20-50°C [3]. The first phase of the gas mixture injection began on 3 June 2014, while tracer tests started three weeks later. By the end of the year 2015, approximately 6280 tonnes of CO2 and 3520 tonnes of H2S had been injected. The gases are dissolved in condensation water, mixed with waste water and injected to 750 m depth into a high temperature reservoir of 200-270°C. Water and gas samples were collected from four monitoring wells. There is a minor increase in CO2 (total dissolved carbon) and H2S (total dissolved sulphite), while the majority of major and minor elements are relatively stable. The data from monitoring wells therefore suggests that some of the injected gas mixture is already stored as minerals in the basaltic reservoir. [1] Sigfusson et al. (2015) Int. J. of Greenh. Gas Control 37, 213-219. [2] Gunnarsson et al. (2013) GRC Transactions 37, 785-789. [3] Matter et al. (2014) Energy Procedia 63, 4180-4185.

  11. Spectroscopic and modeling investigations of the gas-phase chemistry and composition in microwave plasma activated B2H6/Ar/H2 mixtures.

    Science.gov (United States)

    Ma, Jie; Richley, James C; Davies, David R W; Cheesman, Andrew; Ashfold, Michael N R; Mankelevich, Yuri A

    2010-02-25

    This paper describes a three-pronged study of microwave (MW) activated B(2)H(6)/Ar/H(2) plasmas as a precursor to diagnosis of the B(2)H(6)/CH(4)/Ar/H(2) plasmas used for the chemical vapor deposition of B-doped diamond. Absolute column densities of B atoms and BH radicals have been determined by cavity ring-down spectroscopy as a function of height (z) above a molybdenum substrate and of the plasma process conditions (B(2)H(6) and Ar partial pressures, total pressure, and supplied MW power). Optical emission spectroscopy has been used to explore variations in the relative densities of electronically excited BH, H, and H(2) species as a function of the same process conditions and of time after introducing B(2)H(6) into a pre-existing Ar/H(2) plasma. The experimental measurements are complemented by extensive 2-D(r, z) modeling of the plasma chemistry, which results in refinements to the existing B/H chemistry and thermochemistry and demonstrates the potentially substantial loss of gas-phase BH(x) species through reaction with trace quantities of air/O(2) in the process gas mixture and heterogeneous processes occurring at the reactor wall.

  12. Separation of H2O/CO2 Mixtures with Layered Adsorption Method for Greenhouse Gas Control

    Institute of Scientific and Technical Information of China (English)

    XU Dong; ZHANG Jun; LI Gang; XIAO Penny; ZHAI Yu-chun

    2012-01-01

    Multiple-layered vacuum swing adsorption technique was used and investigated in order to effectively keep the feed gas that flows into zeolite 13X zone being dry and keep the CAPEX down(not adding pre-treatment equipment).Activated carbon fiber(ACF) and alumina CDX were laid at the lower parts of the column as pre-layers to selectively adsorb moisture.Zeolite 13X was laid on the top of those two adsorbents as the main layer to capture CO2.Systematic cyclic experiments show that water vapor was successfully contained within the ACF and CDX layers at cyclic steady states.It was also found that ultimate vacuum pressure played a decisive factor for stabilizing the water front,and achieving good CO2 purity and recovery.The findings also reveal the pathway for large-scale CO2 capture process.

  13. Morphology of Diamond Layers Grown on Different Facets of Single Crystal Diamond Substrates by a Microwave Plasma CVD in CH4-H2-N2 Gas Mixtures

    Directory of Open Access Journals (Sweden)

    Evgeny E. Ashkinazi

    2017-06-01

    Full Text Available Epitaxial growth of diamond films on different facets of synthetic IIa-type single crystal (SC high-pressure high temperature (HPHT diamond substrate by a microwave plasma CVD in CH4-H2-N2 gas mixture with the high concentration (4% of nitrogen is studied. A beveled SC diamond embraced with low-index {100}, {110}, {111}, {211}, and {311} faces was used as the substrate. Only the {100} face is found to sustain homoepitaxial growth at the present experimental parameters, while nanocrystalline diamond (NCD films are produced on other planes. This observation is important for the choice of appropriate growth parameters, in particular, for the production of bi-layer or multilayer NCD-on-microcrystalline diamond (MCD superhard coatings on tools when the deposition of continuous conformal NCD film on all facet is required. The development of the film morphology with growth time is examined with SEM. The structure of hillocks, with or without polycrystalline aggregates, that appear on {100} face is analyzed, and the stress field (up to 0.4 GPa within the hillocks is evaluated based on high-resolution mapping of photoluminescence spectra of nitrogen-vacancy NV optical centers in the film.

  14. Stationary afterglow measurements of the temperature dependence of the electron–ion recombination rate coefficients of {{\\rm{H}}}_{2}{{\\rm{D}}}^{+} and {{HD}}_{2}^{+} in He/Ar/H2/D2 gas mixtures at T = 80–145 K 

    Science.gov (United States)

    Plašil, Radek; Dohnal, Petr; Kálosi, Ábel; Roučka, Štěpán; Johnsen, Rainer; Glosík, Juraj

    2017-03-01

    We report measurements of the binary and ternary recombination rate coefficients of deuterated isotopologues of {{{H}}}3+. A cavity ring-down absorption spectrometer was used to monitor the fractional abundances of {{{H}}}3+, {{{H}}}2{{{D}}}+, {{HD}}2+ and {{{D}}}3+ during the decay of a plasma in He/Ar/{{{H}}}2/{{{D}}}2 mixtures. A dependence of the measured effective recombination rate coefficients on the helium buffer gas density was observed and hence both the binary and the ternary recombination rate coefficients for {{{H}}}2{{{D}}}+ and {{HD}}2+ were obtained in the temperature range 80–145 K.

  15. Plasma nitriding of CA-6NM steel: effect of H2 + N2 gas mixtures in nitride layer formation for low N2 contents at 500 ºC

    Directory of Open Access Journals (Sweden)

    Angela Nardelli Allenstein

    2010-12-01

    Full Text Available This work aims to characterize the phases, thickness, hardness and hardness profiles of the nitride layers formed on the CA-6NM martensitic stainless steel which was plasma nitrided in gas mixtures containing different nitrogen amounts. Nitriding was performed at 500 ºC temperature, and 532 Pa (4 Torr pressure, for gas mixtures of 5% N2 + 95% H2, 10% N2 + 90% H2, and 20% N2 + 80% H2, and 2 hours nitriding time. A 6 hours nitriding time condition for gas mixture of 5% N2 + 95% H2 was also studied. Nitrided samples results were compared with non-nitrided condition. Thickness and microstructure of the nitrided layers were characterized by optical microscopy (OM, using Villela and Nital etchants, and the phases were identified by X-ray diffraction. Hardness profiles and hardness measured on surface steel were determined using Vickers hardness and nanoindentation tester, respectively. It was verified that nitrided layer produced in CA-6NM martensitc stainless steel is constituted of compound layer, being that formation of the diffusion zone was not observed for the studied conditions. The higher the nitrogen amounts in gas mixture the higher is the thickness of the nitrided layer and the probability to form different nitride phases, in the case γ'-Fe4N, ε-Fe2-3N and CrN phases. Intrinsic hardness of the nitrided layers produced in the CA-6NM stainless steel is about 12-14 GPa (~1200-1400 HV.

  16. Photolysis of H2O-H2O2 Mixtures: The Destruction of H2O2

    Science.gov (United States)

    Loeffler, M. J.; Fama, M.; Baragiola, R. A.; Carlson, R. W.

    2013-01-01

    We present laboratory results on the loss of H2O2 in solid H2O + H2O2 mixtures at temperatures between 21 and 145 K initiated by UV photolysis (193 nm). Using infrared spectroscopy and microbalance gravimetry, we measured the decrease of the 3.5 micrometer infrared absorption band during UV irradiation and obtained a photodestruction cross section that varies with temperature, being lowest at 70 K. We use our results, along with our previously measured H2O2 production rates via ionizing radiation and ion energy fluxes from the spacecraft to compare H2O2 creation and destruction at icy satellites by ions from their planetary magnetosphere and from solar UV photons. We conclude that, in many cases, H2O2 is not observed on icy satellite surfaces because the H2O2 photodestruction rate is much higher than the production rate via energetic particles, effectively keeping the H2O2 infrared signature at or below the noise level.

  17. Diameter control of gold nanoparticles synthesized in gas phase using atmospheric-pressure H2/Ar plasma jet and gold wire as the nanoparticle source: Control by varying the H2/Ar mixture ratio

    Science.gov (United States)

    Shimizu, Yoshiki

    2017-01-01

    This report describes diameter control of gold nanoparticles (AuNPs) during synthesis using an atmospheric-pressure H2/Ar plasma jet drive with pulse-modulated ultrahigh frequency, employing Au wire as the NP source material. During this process, where most of the AuNPs are regarded as formed through condensation from Au vapor derived by the Au wire etching, the mean diameter varied in the approximate range of 2-12 nm with H2 volume ratios up to 3.9%. In plasma diagnostics, results showed that the H2 volume ratio influences the plasma discharge behaviour, which affects the heat flux density flowed into the Au wire, and the atomic hydrogen concentration in the plasma. Both seemed to influence the etching rate of the Au wire per unit area, which is directly related to the concentration of Au vapor in the plasma. The concentration is one factor affecting the particle size evolution because of the collisions among vapor species in reaction field. Therefore, the AuNP size variation with the H2 volume ratio was discussed from the perspective of the etching rate of the Au wire at each H2 volume ratio.

  18. Diameter control of gold nanoparticles synthesized in gas phase using atmospheric-pressure H2/Ar plasma jet and gold wire as the nanoparticle source: Control by varying the H2/Ar mixture ratio

    Directory of Open Access Journals (Sweden)

    Yoshiki Shimizu

    2017-01-01

    Full Text Available This report describes diameter control of gold nanoparticles (AuNPs during synthesis using an atmospheric-pressure H2/Ar plasma jet drive with pulse-modulated ultrahigh frequency, employing Au wire as the NP source material. During this process, where most of the AuNPs are regarded as formed through condensation from Au vapor derived by the Au wire etching, the mean diameter varied in the approximate range of 2–12 nm with H2 volume ratios up to 3.9%. In plasma diagnostics, results showed that the H2 volume ratio influences the plasma discharge behaviour, which affects the heat flux density flowed into the Au wire, and the atomic hydrogen concentration in the plasma. Both seemed to influence the etching rate of the Au wire per unit area, which is directly related to the concentration of Au vapor in the plasma. The concentration is one factor affecting the particle size evolution because of the collisions among vapor species in reaction field. Therefore, the AuNP size variation with the H2 volume ratio was discussed from the perspective of the etching rate of the Au wire at each H2 volume ratio.

  19. High/variable mixture ratio O2/H2 engine

    Science.gov (United States)

    Adams, A.; Parsley, R. C.

    1988-01-01

    Vehicle/engine analysis studies have identified the High/Dual Mixture Ratio O2/H2 Engine cycle as a leading candidate for an advanced Single Stage to Orbit (SSTO) propulsion system. This cycle is designed to allow operation at a higher than normal O/F ratio of 12 during liftoff and then transition to a more optimum O/F ratio of 6 at altitude. While operation at high mixture ratios lowers specific impulse, the resultant high propellant bulk density and high power density combine to minimize the influence of atmospheric drag and low altitude gravitational forces. Transition to a lower mixture ratio at altitude then provides improved specific impulse relative to a single mixture ratio engine that must select a mixture ratio that is balanced for both low and high altitude operation. This combination of increased altitude specific impulse and high propellant bulk density more than offsets the compromised low altitude performance and results in an overall mission benefit. Two areas of technical concern relative to the execution of this dual mixture ratio cycle concept are addressed. First, actions required to transition from high to low mixture ratio are examined, including an assessment of the main chamber environment as the main chamber mixture ratio passes through stoichiometric. Secondly, two approaches to meet a requirement for high turbine power at high mixture ratio condition are examined. One approach uses high turbine temperature to produce the power and requires cooled turbines. The other approach incorporates an oxidizer-rich preburner to increase turbine work capability via increased turbine mass flow.

  20. Combustion of CH4/H2/air mixtures in catalytic microreactors.

    Science.gov (United States)

    Specchia, Stefania; Vella, Luigi D; Burelli, Sara; Saracco, Guido; Specchia, Vito

    2009-03-23

    The combustion of CH(4)/H(2)/HC mixtures in a very small space represents an alternative, innovative way to produce thermal/electrical energy. Pd/NiCrO(4) catalysts are lined on SiC monoliths via in situ solution combustion synthesis (SCS), and the monoliths are then tested by feeding CH(4), H(2), and lean CH(4)/H(2) mixtures into a lab-scale test rig at an output thermal power of 7.6 MW(th) m(-3). In all cases, the combustion temperature shifts to values lower than those observed in non-catalytic combustion. When the power density is kept constant (by adding H(2) to the gas mixture), the value of CH(4)-T(50) (the half-conversion temperature of CH(4)) decreases relative to that of pure CH(4), and the slope of the conversion curve becomes steeper. The higher the H(2) concentration is, the higher the reactivity of the mixture towards CH(4) oxidation-probably due to a higher production of H(2) reactive radicals (OH).

  1. Selectivity and self-diffusion of CO2 and H2 in a mixture on a graphite surface

    NARCIS (Netherlands)

    Trinh, T.T.; Vlugt, T.J.H.; Hägg, M.-B.; Bedeaux, D.; Kjelstrup, S.H.

    2013-01-01

    We performed classical molecular dynamics (MD) simulations to understand the mechanism of adsorption from a gas mixture of CO2 and H2 (mole fraction of CO2 = 0.30) and diffusion along a graphite surface, with the aim to help enrich industrial off-gases in CO2, separating out H2. The temperature of

  2. Selectivity and self-diffusion of CO2 and H2 in a mixture on a graphite surface

    NARCIS (Netherlands)

    Trinh, T.T.; Vlugt, T.J.H.; Hägg, M.-B.; Bedeaux, D.; Kjelstrup, S.H.

    2013-01-01

    We performed classical molecular dynamics (MD) simulations to understand the mechanism of adsorption from a gas mixture of CO2 and H2 (mole fraction of CO2 = 0.30) and diffusion along a graphite surface, with the aim to help enrich industrial off-gases in CO2, separating out H2. The temperature of t

  3. Inhomogeneous speed effects on H2 vibrational line profiles in ternary mixtures

    Science.gov (United States)

    Joubert, P.; Bruet, X.; Bonamy, J.; Robert, D.; Chaussard, F.; Saint-Loup, R.; Berger, H.

    2000-12-01

    A study of speed inhomogeneous broadening of the hydrogen vibrational line profiles in the collisional regime for ternary mixtures is reported. The Q(1) line of H2 in H2-Ar-N2, H2-He-Ar, and H2-He-N2 mixtures is investigated by high resolution stimulated Raman spectroscopy for various concentrations and temperatures. A model, successfully used for binary mixtures, is extended to ternary mixtures. An excellent agreement is obtained between theory and experiment for H2-Ar-N2, by using the collisional parameters previously obtained from binary mixtures study. For H2-He-Ar and H2-He-N2, H2-He collisions play a "hardening" effect in the H2 soft speed memory mechanism for H2-Ar or H2-N2. The present experimental results allow us, via the frame of our model, to determine the "hardness" parameter values for H2-He (inaccessible from binary mixtures data) and to get an accurate description of the spectral line shape. This study should be useful for hydrogen coherent anti-Stokes Raman spectroscopy thermometry in H2/air flames at high pressure through its possible extension to the H2-N2-H2O system.

  4. Nanoparticle formation in H2O/N-2 and H2O/Ar mixtures under irradiation by 20 MeV protons and positive corona discharge

    DEFF Research Database (Denmark)

    Imanaka, M.; Tomita, S.; Kanda, S.

    2010-01-01

    To investigate the contribution of ions to gas nucleation, we have performed experiments on the formation of water droplets in H2O/N-2 and H2O/Ar gas mixtures by irradiation with a 20 MeV proton beam and by positive corona discharge. The size of the formed nanoparticles was measured using a diffe...... positive and negative ions for the formation of nanosize droplets, which attract each other by Coulomb interactions, enhancing the collision frequency and leading to the formation of the 10 nm droplets.......To investigate the contribution of ions to gas nucleation, we have performed experiments on the formation of water droplets in H2O/N-2 and H2O/Ar gas mixtures by irradiation with a 20 MeV proton beam and by positive corona discharge. The size of the formed nanoparticles was measured using...... a differential mobility analyzer equipped with a Faraday cup electrometer. Using the proton beam, droplets around 10 nm in diameter were observed for both positively and negatively charged particles, but none were found when the corona discharge was used. This implies the importance of the presence of both...

  5. Cathodic H2 gas production through Pd alloy membrane electrodes

    Science.gov (United States)

    Shirogami, T.; Murata, K.

    A rechargeable H2-NiOOH cell with hydrogen-permeable membrane electrode was tested, and its cathodic hydrogen gas production through the membrane electrode investigated. When a Pd-Pt, catalyzed electrolyte-facing surface was cathodically polarized in a concentrated KOH solution, it was found that hydrogen gas was evolved in the chamber through dissolved hydrogen atoms' penetrating of the membrane to exit at the other, palladized surface as free gas.

  6. Glitters of warm H2 in cold diffuse molecular gas

    NARCIS (Netherlands)

    Falgarone, Edith; Beichman, Chaz; Boulanger, Francois; Combes, Francoise; Gry, Cecile; Helou, Georges; Laureijs, Rene; Pineau Des Forets, Guillaume; Valentijn, Edwin; Verstraete, Laurent

    2004-01-01

    Cold molecular hydrogen, a possibly dominant gas fraction in galaxies, does not radiate due to the symmetry and small moment of inertia of the molecule. The only tracers of cold H2, the rotational lines of CO and dust thermal emission operate only in metal-rich environments. By detecting the lowest

  7. Steady-state studies of the reactions of H2O-CO and CO2-H2 mixtures with liquid iron

    Science.gov (United States)

    Sasaki, Y.; Belton, G. R.

    1998-08-01

    Studies have been made of the steady-stata composition of liquid iron exposed to high flow rates of H2O-CO mixtures at 1550 °C to 1700 °C and CO2-H2 mixtures at 1600 °C. Values of the steady-state activity of oxygen have been established by measurement of either the carbon concentration or the silicon concentration when the iron was held in a silica crucible. Additions of sulfur or selenium to the iron have been found to result in steady-state oxygen activities, which differ significantly from those expected from water-gas equilibrium. The results are interpreted to show that the ratio of the apparent first-order rate constants for the reactions of H2O and CO2 with liquid iron is about 3 at 1600 °C. It is shown that the dependencies of the rate constants on the activities of sulfur, oxygen, and selenium must, even if complex, be similar for the H2O and CO2 reactions with liquid iron, to a good approximation.

  8. CO2-H2 gas separation by physical adsorption

    Science.gov (United States)

    Maiga, Sidi; Mbaye, Mamadou; Gatica, Silvina

    2011-04-01

    In the advancement of Hydrogen-based economy, the efficient production of H2 represents an issue for commercial applications. Regardless of the method, H2 purification ultimately equates to a CO2 removal process. Gas separation by adsorption can be accomplished by three basic physical mechanisms: equilibrium, steric and kinetic. Equilibrium mechanisms are based on the strength of the attraction of the gases to the substrate; the kinetic mechanisms are those based on the differences in the rates of adsorption and/or transport of the gas on and through the substrate; and the steric mechanisms are based on the incompatibility between the size or shape of the pores in the substrate and those of the adsorbate gas molecules. Many materials have been used for this purpose during the past half century, including carbon nanotubes (NTs), activated carbons and zeolites. Within the arena of gas separations, ``Metal-Organic Frameworks'' (MOFs) or Carbon Nanohorns (CNHs) are promising materials. We have studied the energy space distribution of CO2and H2 in MOFs and CNHs and found that based on the energetics the materials may be used for gas separation processes. Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund and to the National Science Foundation under Grant No. DMR-1006010 for partial support of this research.

  9. Synthesis, structural and hydrogenation properties of Mg-rich MgH2-TiH2 nanocomposites prepared by reactive ball milling under hydrogen gas.

    Science.gov (United States)

    Cuevas, Fermin; Korablov, Dmytro; Latroche, Michel

    2012-01-21

    MgH(2)-TiH(2) nanocomposites have been obtained by reactive ball milling of elemental powders under 8 MPa of hydrogen pressure. The composites consist of a mixture of β-rutile MgH(2), γ-orthorhombic high pressure MgH(2) and ε-tetragonal TiH(2) phases with nanosized crystallites ranging from 4 to 12 nm. In situ hydrogen absorption curves on milling reveal that nanocomposite formation occurs in less than 50 min through the consecutive synthesis of the TiH(2) and MgH(2) phases. The abrasive and catalytic properties of TiH(2) speed up the formation of the MgH(2) phase. Thermodynamic, kinetic and cycling hydrogenation properties have been determined for the 0.7MgH(2)-0.3TiH(2) composite and compared to nanometric MgH(2). Only the MgH(2) phase desorbs hydrogen reversibly at moderate temperature (523 to 598 K) and pressure (10(-3) to 1 MPa). The presence of TiH(2) does not modify the thermodynamic properties of the Mg/MgH(2) system. However, the MgH(2)-TiH(2) nanocomposite exhibits outstanding kinetic properties and cycling stability. At 573 K, H-sorption takes place in less than 100 s. This is 20 times faster than for a pure nanometric MgH(2) powder. We demonstrate that the TiH(2) phase inhibits grain coarsening of Mg, which allows extended nucleation of the MgH(2) phase in Mg nanoparticles before a continuous and blocking MgH(2) hydride layer is formed. The low crystallinity of the TiH(2) phase and its hydrogenation properties are also compatible with a gateway mechanism for hydrogen transfer from the gas phase to Mg. Mg-rich MgH(2)-TiH(2) nanocomposites are an excellent media for hydrogen storage at moderate temperatures.

  10. He-H2 mixture and Er3NiHx packing for the refrigeration enhancement of pulse tube refrigerator

    Institute of Scientific and Technical Information of China (English)

    CHEN Guobang; TANG Ke; HUANG Yonghua; GAN Zhihua; BAO Rui

    2004-01-01

    The computation with the theory of modified Brayton Cycle indicates that higher cooling power and coefficient of performance for a pulse tube refrigerator can be achieved with He-H2 mixture as working gas than those with pure He in the temperature region of 30 K. In addition, it is found that Er3Ni, a regenerative material, is able to absorb H2 and produces Er3NiHx. The computation presents that the regenerative performance of Er3NiHx is better than that of Er3Ni due to its higher volume specific heat. Experimental results show that the pulse tube refrigeration performance in 30 K temperature region is enhanced greatly with He-H2mixture and Er3NiHx packing.

  11. Experimental Study of Gas Explosions in Hydrogen Sulfide-Natural Gas-Air Mixtures

    Directory of Open Access Journals (Sweden)

    André Vagner Gaathaug

    2014-01-01

    Full Text Available An experimental study of turbulent combustion of hydrogen sulfide (H2S and natural gas was performed to provide reference data for verification of CFD codes and direct comparison. Hydrogen sulfide is present in most crude oil sources, and the explosion behaviour of pure H2S and mixtures with natural gas is important to address. The explosion behaviour was studied in a four-meter-long square pipe. The first two meters of the pipe had obstacles while the rest was smooth. Pressure transducers were used to measure the combustion in the pipe. The pure H2S gave slightly lower explosion pressure than pure natural gas for lean-to-stoichiometric mixtures. The rich H2S gave higher pressure than natural gas. Mixtures of H2S and natural gas were also studied and pressure spikes were observed when 5% and 10% H2S were added to natural gas and also when 5% and 10% natural gas were added to H2S. The addition of 5% H2S to natural gas resulted in higher pressure than pure H2S and pure natural gas. The 5% mixture gave much faster combustion than pure natural gas under fuel rich conditions.

  12. Phase Separation Kinetics in Isopycnic Mixtures of H2O/CO2/Ethoxylated Alcohol Surfactants

    Science.gov (United States)

    Lesemann, Markus; Paulaitis, Michael E.; Kaler, Eric W.

    1999-01-01

    Ternary mixtures of H2O and CO2 with ethoxylated alcohol (C(sub i)E(sub j)) surfactants form three coexisting liquid phases at conditions where two of the phases have equal densities (isopycnic phases). Isopycnic phase behavior has been observed for mixtures containing C8E5, C10E6, and C12E6 surfactants, but not for those mixtures containing either C4E1 or C8E3 surfactants. Pressure-temperature (PT) projections for this three-phase equilibrium were determined for H2O/CO2/C8E5 and H2O/CO2/C10E6 mixtures at temperatures from approximately 25 to 33 C and pressures between 90 and 350 bar. Measurements of the microstructure in H2O/CO2/C12E6 mixtures as a function of temperature (25-31 C), pressure (63.1-90.7 bar), and CO2 composition (0-3.9 wt%) have also been carried out to show that while micellar structure remains essentially un-changed, critical concentration fluctuations increase as the phase boundary and plait point are approached. In this report, we present our first measurements of the kinetics of isopycnic phase separation for ternary mixtures of H2O/CO2/C8E5.

  13. Selectivity and Self Diffusion of CO2 and h2 in a Mixture on a Graphite Surface

    Science.gov (United States)

    Trinh, Thuat; Kjelstrup, Signe; Vlugt, Thijs; Bedeaux, Dick; Hägg, May-Britt

    2013-12-01

    We performed classical molecular dynamics (MD) simulations to understand the mechanism of adsorption from a gas mixture of CO2 and H2 (mole fraction of CO2 = 0.30) and diffusion along a graphite surface, with the aim to help enrich industrial off-gases in CO2, separating out H2. The temperature of the system in the simulation covered typical industrial conditions for off-gas treatment (250 ̶ 550K). The interaction energy of single molecules CO2 or H2 on graphite surface was calculated with classical force fields and with Density Functional Theory (DFT). The results were in good agreement. The binding energy of CO2 on graphite surface is three times larger than that of H2. At lower temperatures, the selectivity of CO2 over H2 is five times larger than at higher temperatures. The position of the dividing surface was used to explain how the adsorption varies with pore size. In the temperature range studied, the self-diffusion coefficient of CO2 is always smaller than of H2. The temperature variation of the selectivities and the self diffusion coefficient imply that the carbon molecular sieve membrane can be used for gas enrichment of CO2.

  14. Selectivity and self-diffusion of CO2 and H2 in a mixture on a graphite surface.

    Science.gov (United States)

    Trinh, Thuat T; Vlugt, Thijs J H; Hägg, May-Britt; Bedeaux, Dick; Kjelstrup, Signe

    2013-01-01

    We performed classical molecular dynamics (MD) simulations to understand the mechanism of adsorption from a gas mixture of CO2 and H2 (mole fraction of CO2 = 0.30) and diffusion along a graphite surface, with the aim to help enrich industrial off-gases in CO2, separating out H2. The temperature of the system in the simulation covered typical industrial conditions for off-gas treatment (250-550 K). The interaction energy of single molecules CO2 or H2 on graphite surface was calculated with classical force fields (FFs) and with Density Functional Theory (DFT). The results were in good agreement. The binding energy of CO2 on graphite surface is three times larger than that of H2. At lower temperatures, the selectivity of CO2 over H2 is five times larger than at higher temperatures. The position of the dividing surface was used to explain how the adsorption varies with pore size. In the temperature range studied, the self-diffusion coefficient of CO2 is always smaller than of H2. The temperature variation of the selectivities and the self-diffusion coefficient imply that the carbon molecular sieve membrane can be used for gas enrichment of CO2.

  15. SELECTIVITY AND SELF DIFFUSION OF CO2 AND H2 IN A MIXTURE ON A GRAPHITE SURFACE

    Directory of Open Access Journals (Sweden)

    Thuat Thanh Trinh

    2013-12-01

    Full Text Available We performed classical molecular dynamics (MD simulations to understand the mechanism of adsorption from a gas mixture of CO2 and H2 (mole fraction of CO2 = 0.30 and diffusion along a graphite surface, with the aim to help enrich industrial off-gases in CO2, separating out H2. The temperature of the system in the simulation covered typical industrial conditions for off-gas treatment (250 ̶ 550K. The interaction energy of single molecules CO2 or H2 on graphite surface was calculated with classical force fields and with Density Functional Theory (DFT. The results were in good agreement. The binding energy of CO2 on graphite surface is three times larger than that of H2. At lower temperatures, the selectivity of CO2 over H2 is five times larger than at higher temperatures. The position of the dividing surface was used to explain how the adsorption varies with pore size. In the temperature range studied, the self-diffusion coefficient of CO2 is always smaller than of H2. The temperature variation of the selectivities and the self diffusion coefficient imply that the carbon molecular sieve membrane can be used for gas enrichment of CO2.

  16. Study of nanosecond discharges in different H2 air mixtures at atmospheric pressure for plasma-assisted applications

    Science.gov (United States)

    Bourdon, Anne; Kobayashi, Sumire; Bonaventura, Zdenek; Tholin, Fabien; Popov, Nikolay

    2016-09-01

    This paper presents 2D simulations of nanosecond pulsed discharges between two point electrodes in different H2/air mixtures and in air at atmospheric pressure. A fluid model is coupled with detailed kinetic schemes for air and different H2/air mixtures to simulate the discharge dynamics. First, as the positive and negative ionization waves propagate in the interelectrode gap, it has been observed that in H2/air mixtures with equivalence ratios between 0.3 and 2, major positive ions produced by the nanosecond discharge are N2+,O2+and HN2+.The discharge dynamics is shown to vary only slightly for equivalence ratios of the H2/air mixture between 0.3 and 2. Then, as the discharge transits to a nanosecond spark discharge, we have studied the different chemical reactions that lead to fast gas heating and to the production of radicals, as O,H and OH. Both thermal and chemical effects of the nanosecond spark discharge are of interest for plasma assisted combustion applications. This work has been supported by the project DRACO (Grant No. ANR-13-IS09-0004) and the french russian LIA Kappa.

  17. Equations of state for H2, H2O, and H2-H2O fluid mixtures at temperatures above 0.01° C and at high pressures

    Science.gov (United States)

    Rimbach, Helmut; Chatterjee, Niranjan D.

    1987-11-01

    Modified Redlich-Kwong (MRK) equations of state have been derived for the pure fluid species H2 and H2O by expressing the parameter a as a function of T and P, and b as as a function of P only. These equations are valid above 0° and 0.01° C, respectively. For H2O, the prediction of volumes is successful not only in the supercritical, but also in the subcritical range. As a result of this, the saturation curve of H2O can be calculated with a maximum deviation of ±1.4 bar in the range 100 350° C. Between 350° C and the critical point (374.15° C), the uncertainty increases somewhat; this is due to a fundamental inadequacy of the Redlich-Kwong equation itself. These equations of state permit extrapolations to pressures of 100 kbar for H2 and at least 200 kbar for H2O and are, therefore, eminently suited for geochemical applications. Formulation of the MRK of the binary H2-H2O mixtures was achieved by assuming the quadratic mixing rule for the parameters a mix and b+mix. To derive the cross coefficients, aH2-H2Oand b H 2-H 2O, adjustable corrective factors ɛ and τ had to be introduced. The T- and P-dependences of ɛ and τ are based on P-V-T-X H 2 data (Seward and Franck 1981) to 440° C and 2500 bar. The resulting equation of state very satisfactorily reproduces the volumes observed experimentally at various sets of T, P, and X H 2. At a total pressure of 2 kbar, positive deviation from ideal mixing behaviour is still perceptible at as high a temperature as 1000° C. At some temperature around 380° C, phase separation sets in, an aqueous solution with dissolved H2 coexisting in equilibrium with an H2-rich fluid with dissolved H2O. The computed P-T-X H 2 surface of this two-phase region agrees well with that observed in Seward and Franck's (1981) experiments. An independent proof of the validity of this equation of state is the accuracy with which H {m/ex}can be predicted. Calorimetric measurements of H {m/ex}(Smith et al. 1983, Wormald and Colling 1985

  18. Formation of H2-He substellar bodies in cold conditions. Gravitational stability of binary mixtures in a phase transition

    Science.gov (United States)

    Füglistaler, A.; Pfenniger, D.

    2016-06-01

    Context. Molecular clouds typically consist of 3/4 H2, 1/4 He and traces of heavier elements. In an earlier work we showed that at very low temperatures and high densities, H2 can be in a phase transition leading to the formation of ice clumps as large as comets or even planets. However, He has very different chemical properties and no phase transition is expected before H2 in dense interstellar medium conditions. The gravitational stability of fluid mixtures has been studied before, but these studies did not include a phase transition. Aims: We study the gravitational stability of binary fluid mixtures with special emphasis on when one component is in a phase transition. The numerical results are aimed at applications in molecular cloud conditions, but the theoretical results are more general. Methods: First, we study the gravitational stability of van der Waals fluid mixtures using linearized analysis and examine virial equilibrium conditions using the Lennard-Jones intermolecular potential. Then, combining the Lennard-Jones and gravitational potentials, the non-linear dynamics of fluid mixtures are studied via computer simulations using the molecular dynamics code LAMMPS. Results: Along with the classical, ideal-gas Jeans instability criterion, a fluid mixture is always gravitationally unstable if it is in a phase transition because compression does not increase pressure. However, the condensed phase fraction increases. In unstable situations the species can separate: in some conditions He precipitates faster than H2, while in other conditions the converse occurs. Also, for an initial gas phase collapse the geometry is essential. Contrary to spherical or filamentary collapses, sheet-like collapses starting below 15 K easily reach H2 condensation conditions because then they are fastest and both the increase of heating and opacity are limited. Conclusions: Depending on density, temperature and mass, either rocky H2 planetoids, or gaseous He planetoids form. H2

  19. Aggregation Properties of an Amphiphilic Methanofullerene Derivative in THF-H2O Solvent Mixtures

    Institute of Scientific and Technical Information of China (English)

    Guan Wu WANG; Li Juan JIAO; Er Hong HAO; Yong Ming LU; You Jun YANG

    2004-01-01

    Amphiphilic methanofullerene 1 exhibits strong tendency to form aggregates in THF-H2O solvent mixtures. Two different aggregation processes induced by either varying the solvent composition or upon standing have been found. Concentration has great influence on the aggregation process. Paralleling to the UV-Vis changes, an unusual solvatochromism has been observed in these two different processes.

  20. Xe-containing fast gas mixtures for gas-filled detectors

    Science.gov (United States)

    Christophorou, L. G.; Maxey, D. V.; McCorkle, D. L.; Carter, J. G.

    1980-05-01

    Electron drift velocities are reported for XeCF 4, XeC 2H 2 and XeCF 4C 2H 2 mixtures. For a number of these mixtures the drift velocities are large (4 to 10 × 10 6 cm s -1) over a range of {E}/{P} values below 3.5 V cm -1 Torr -1. Such mixtures may find application in gas-filled detectors, especially those involving electromagnetic ionizing radiation.

  1. Theoretical calculation of the shock compression properties of liquid H2 + D2 mixtures

    Institute of Scientific and Technical Information of China (English)

    陈其峰; 蔡灵仓; 陈栋泉; 经福谦

    1999-01-01

    Based on liquid variational perturbation theory with quantum mechanics correction, the effective exp-6 potential is adopted to compute the shock Hugoniot of liquid H2+D2 mixtures at different molar rations. An examination of the confidence of the above computation is performed by comparing experiments and calculations, in which similar calculation procedure used for H2+D2 is adopted for H2 and D2 each, since no experimental data are available to conduct this kind of comparison. Good agreement in both comparisons is found. This fact may look as if an indirect positive verification of calculation procedure was used here at least in the pressure and temperature domain covered by the experimental data of H2 and D2 used for comparison, numerically nearly up to 20 GPa and 104 K.

  2. Extra-terrestrial sprites: laboratory investigations in planetary gas mixtures

    NARCIS (Netherlands)

    Dubrovin, D.; Yair, Y.; Price, C.; Nijdam, S.; Clevis, T.T.J.; Veldhuizen, E.M. van; Ebert, U.

    2012-01-01

    We investigate streamers in gas mixtures representing the atmospheres of Jupiter, Saturn (H2-He) and Venus (CO2-N2). Streamer diameters, velocities, radiance and overall morphology are investigated with fast ICCD camera images. We confirm experimentally the scaling of streamer diameters in these gas

  3. Study of the transient "free" OH radical generated in H2O-H2O2 mixtures by stimulated Raman scattering

    Science.gov (United States)

    Li, Fangfang; Ma, Zhiwei; Wang, Shenghan; Li, Tianyu; Sun, Chenglin; Li, Zhanlong; Men, Zhiwei

    2017-03-01

    Forward and backward stimulated Raman scattering (SRS) were studied in the H2O2-H2O mixtures by a strong excitation laser with 532 nm. Only the backward SRS (BSRS) of the H2O2-H2O system shows an unexpected SRS shoulder peak at around 3600 cm- 1, which is similar to the characteristic peak of "free" OH radical. The generation of the "free" OH radical is mainly attributed to the dissociation of hydrogen peroxide (HP) molecules. Simultaneously, the ionization of HP-water clusters generates a part of "free" OH radical under the Laser-induced breakdown (LIB). The interaction of water and HP is also discussed.

  4. High quality boron-doped epitaxial layers grown at 200°C from SiF4/H2/Ar gas mixtures for emitter formation in crystalline silicon solar cells

    Science.gov (United States)

    Léal, Ronan; Haddad, Farah; Poulain, Gilles; Maurice, Jean-Luc; Roca i Cabarrocas, Pere

    2017-02-01

    Controlling the doping profile in solar cells emitter and front/back surface field is mandatory to reach high efficiencies. In the current state of the art, these doped layers are made by dopant diffusion at around 900°C, which implies potential temperature induced damages in the c-Si absorber and for which a precise control of doping is difficult. An alternative solution based on boron-doped epitaxial silicon layers grown by plasma-enhanced chemical vapor deposition (PECVD) from 200°C using SiF4/H2/Ar/B2H6 chemistry is reported. The structural properties of the doped and undoped epitaxial layers were assessed by spectroscopic ellipsometry (SE), high resolution transmission electron microscopy (HR-TEM) and X-ray diffraction (XRD). The incorporation of boron has been studied via plasma profiling time of flight mass spectrometry (PP-TOFMS) and secondary ion mass spectrometry (SIMS) measurements. The boron-doped epitaxial layers revealed excellent structural and electrical properties even for high carrier concentrations (>1019cm-3). Sheet resistances between 100 and 130 Ω/sq can been obtained depending on the thickness and the doping concentration, which is within the range of targeted values for emitters in c-Si solar cells. Electrochemical capacitance voltage (ECV) revealed a uniform doping profile around 3.1019 cm-3 and by comparing with SIMS measurement a doping efficiency around 50% has been found.

  5. High quality boron-doped epitaxial layers grown at 200°C from SiF4/H2/Ar gas mixtures for emitter formation in crystalline silicon solar cells

    Directory of Open Access Journals (Sweden)

    Ronan Léal

    2017-02-01

    Full Text Available Controlling the doping profile in solar cells emitter and front/back surface field is mandatory to reach high efficiencies. In the current state of the art, these doped layers are made by dopant diffusion at around 900°C, which implies potential temperature induced damages in the c-Si absorber and for which a precise control of doping is difficult. An alternative solution based on boron-doped epitaxial silicon layers grown by plasma-enhanced chemical vapor deposition (PECVD from 200°C using SiF4/H2/Ar/B2H6 chemistry is reported. The structural properties of the doped and undoped epitaxial layers were assessed by spectroscopic ellipsometry (SE, high resolution transmission electron microscopy (HR-TEM and X-ray diffraction (XRD. The incorporation of boron has been studied via plasma profiling time of flight mass spectrometry (PP-TOFMS and secondary ion mass spectrometry (SIMS measurements. The boron-doped epitaxial layers revealed excellent structural and electrical properties even for high carrier concentrations (>1019cm-3. Sheet resistances between 100 and 130 Ω/sq can been obtained depending on the thickness and the doping concentration, which is within the range of targeted values for emitters in c-Si solar cells. Electrochemical capacitance voltage (ECV revealed a uniform doping profile around 3.1019 cm-3 and by comparing with SIMS measurement a doping efficiency around 50% has been found.

  6. Secondary electron emission from solid HD and a solid H2-D2 mixture

    DEFF Research Database (Denmark)

    Sørensen, H.; Børgesen, P.; Hao-Ming, Chen

    1983-01-01

    Secondary electron emission from solid HD and a solid 0.6 H2 + 0.4 D2 mixture has been studied for electron and hydrogen ion bombardment at primary energies from 0.5 to 3 keV and 2 to 10 keV/amu, respectively. The yield for solid HD is well explained by a simple stoichiometric model of the low......-energy stopping power for the internal secondaries. The secondary electron yield from the mixture is somewhat larger than the expected value, but lies between the values for pure solid H2 and D2. The secondary electron emission coefficient for solid tritium may be determined from a linear extrapolation...... of the present data....

  7. Study of nanosecond discharges in H2-air mixtures at atmospheric pressure for plasma assisted combustion applications

    Science.gov (United States)

    Kobayashi, Sumire; Bonaventura, Zdeněk; Tholin, Fabien; Popov, Nikolay A.; Bourdon, Anne

    2017-07-01

    This paper presents 2D simulations of nanosecond discharges between two point electrodes for four different H2-air mixtures defined by their equivalence ratios ϕ (i.e. φ =0, air, φ =0.3, lean mixture, φ =1, stoichiometric mixture and φ =1.5, rich mixture) at atmospheric pressure and at an initial temperature of 1000 K. In a first step, we have shown that the mixture composition has only a very small influence on the discharge dynamics and structure during the streamer phase and up to the formation of the plasma channel between the two point electrodes in H2-air mixtures with φ \\in [0,1.5]. However, as the plasma channel is formed slightly earlier as the equivalence ratio increases, for a given voltage pulse, the duration of the nanosecond spark phase increases as the equivalence ratio increases. As expected, we have shown that excited states of N2 (and in particular N2(A)) and radicals (and in particular O(D), O(P), H and OH) are very efficiently produced during the voltage pulse after the start of the spark phase. After the voltage pulse, and up to 100 ns, the densities of excited states of N2 and of O(D) decrease. Conversely, most of the O(P), H and OH radicals are produced after the voltage pulse due to the dissociative quenching of electronically excited N2. As for radicals, the gas temperature starts increasing after the start of the spark phase. For all studied mixtures, the density of O(P) atoms and the gas temperature reach their maxima after the end of the voltage pulse and the densities of O(P), H and OH radicals and the maximal gas temperature increase as the equivalence ratio increases. We have shown that the production of radicals is the highest on the discharge axis and the distribution of species after the voltage pulse and up to 100 ns has a larger diameter between the electrodes than close to both electrode tips. As for species, the temperature distribution presents two hot spots close to the point electrode tips. The non

  8. Experimental study of CH4/H2 mixtures-LPG-gasoline in internal combustion engines

    Energy Technology Data Exchange (ETDEWEB)

    Bayrak, Mehmet; Albayrak Ceper, Bilge; Kahraman, Nafiz; Orhan Akansu, Selahaddin [Dept. of Mechanical Engineering, Erciyes University Engineering Faculty (Turkey)], e-mail: akansu@erciyes.edu.tr

    2011-07-01

    With the depletion of fossil fuel and the rising concerns about the environment, there is an urgent need for alternative fuels with low environmental impact. Research has been carried out world-wide to determine the energetic and environmental performance of alternative fuels in existing engines and the aim of this paper is to study the performance of engines using CH4/H2 (90% CH4 and 10% H2), liquefied petroleum gas (LPG) and gasoline. Experiments were conducted on a Kathana engine running at between 1500 and 3500 rotations per minutes and with spark timing between 10 and 35 BTDC. It was found that the CH4/H2 mix provides the lowest pollutant emission values of the studied fuels and the lowest brake thermal efficiency. This study provided a better understanding of the exhaust emission and combustion performances of CH4/H2 and LPG compared to gasoline.

  9. Thermal Pressure in Diffuse H2 Gas Measured by Herschel [C II] Emission and FUSE UV H2 Absorption

    Science.gov (United States)

    Velusamy, T.; Langer, W. D.; Goldsmith, P. F.; Pineda, J. L.

    2017-04-01

    UV absorption studies with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite have made important observations of H2 molecular gas in Galactic interstellar translucent and diffuse clouds. Observations of the 158 μm [C ii] fine-structure line with Herschel trace the same H2 molecular gas in emission. We present [C ii] observations along 27 lines of sight (LOSs) toward target stars of which 25 have FUSE H2 UV absorption. Two stars have only HST STIS C ii λ2325 absorption data. We detect [C ii] 158 μm emission features in all but one target LOS. For three target LOSs that are close to the Galactic plane, | {\\text{}}b| UV absorption data. We present the H2 gas densities and thermal pressures for 26 target LOSs and from the [C ii] intensities derive a mean thermal pressure in the range of ˜6100-7700 K cm-3 in diffuse H2 clouds. We discuss the thermal pressures and densities toward 14 targets, comparing them to results obtained using the UV absorption data for two other tracers C i and CO. Our results demonstrate the richness of the far-IR [C ii] spectral data which is a valuable complement to the UV H2 absorption data for studying diffuse H2 molecular clouds. While the UV absorption is restricted to the directions of the target star, far-IR [C ii] line emission offers an opportunity to employ velocity-resolved spectral-line mapping capability to study in detail the clouds’ spatial and velocity structures.

  10. Absorbent of CuCI/NaY Prepared by Glucose Direct Reduction and the Application for Adsorption of CO and Separation for CO/H2 Mixture Gas%葡萄糖还原法制备CuCl/NaY吸附剂及其CO吸附和CO/H2分离性能

    Institute of Scientific and Technical Information of China (English)

    孙思; 吴永永; 罗仕忠; 储伟; 倪宏志

    2011-01-01

    CuCI/NaY sorbents were prepared via incipient wetness impregnation method under mild condition with copper chloride as metal precursor and glucose as reducing agent. The efficient adsorption amount of CO and the separation coefficient of CO/H2 on the sorbents were measured by dynamic adsorption process. The microstructures of the sorbents were characterized by X-ray diffraction (XRD) , X-ray photoelectron spectrosco-py(XPS) and temperature programmed reduction (TPR) techniques. The results showed that the sorbent prepared using glucose as reducing agent possessed higher amounts of Cu + than that without glucose, and resulted in a better adsorption capability of CO and separation performance of CO/H%以NaY分子筛为载体,CuCl2为铜源,加入还原剂葡萄糖,在温和条件下制备了CuCl/NaY吸附剂,通过变压吸附考察了其对CO的吸附性能及对CO/H2的分离性能.利用X射线衍射(XRD)、X射线光电子能谱(XPS)及程序升温还原谱(TPR)技术对吸附剂进行了表征.结果表明,采用葡萄糖还原法制备CuCl/NaY吸附剂的条件温和,吸附剂表面的亚铜含量高,对CO的吸附及CO/H2的分离性能优越且稳定性好.

  11. Production of Methanol-Higher Alcohol Mixtures from Natural Gas via Syngas Chemistry Production de mélanges méthanol-alcools supérieurs à partir du gaz, via (CO + H2

    Directory of Open Access Journals (Sweden)

    Courty P.

    2006-11-01

    Full Text Available Despite the prevailing position of ethers (MTBE, TAME as octane boosters, and the low oil prices at present, alcohol synthesis remains one of the near future means of natural gas upgrading via syngas chemistry. After a review of the available process development data in the field, this paper focuses on the IFP process studies, based on the CuCo and CuNi catalysts developed by Institut Français du Pétrole (IFR, France and Idemitsu Kosan (Japan. The adequacy between the product specifications, and the optimization of the performances is then discussed in a technico-economic context, together with a presentation of lab scale, pilot scale and demonstration scale test results. As a conclusion, a prospective overall view brings together todays economics and some improvement guidelines dealing with investments, operating cost and catalyst performances. Cette publication présente les travaux de R & D (Recherche et Développement menés par l'Institut Français du Pétrole (IFP, France et Idemitsu Kosan (Japon en synthèse d'alcools. Elle situe les résultats dans le contexte technique et économique actuel. L'accroissement constant des ressources prouvées en gaz et, chronologiquement, les deux crises pétrolières, la suppression du plomb dans les essences, ont conduit le monde industriel à intensifier les recherches concernant la synthèse d'alcools. Très récemment, les effets bénéfiques de l'addition d'alcools sur les émissions de polluants ont été mis en évidence. Toutefois, l'additivation de carburants par les alcools est en voie de disparition au profit des éthers, alors que, indépendamment, les procédés de production d'ammoniac, de méthanol, d'acide acétique, également fondés sur le gaz, se sont seuls développés. La synthèse d'alcools a fait l'objet de nombreux travaux, résumés dans les tableaux 1 et 2. L'étude des différents aspects réactionnels amène à prendre en compte l'exothermicité importante des r

  12. Experimental investigations and geochemical modelling of site-specific fluid-fluid and fluid-rock interactions in underground storage of CO2/H2/CH4 mixtures: the H2STORE project

    Science.gov (United States)

    De Lucia, Marco; Pilz, Peter

    2015-04-01

    Underground gas storage is increasingly regarded as a technically viable option for meeting the energy demand and environmental targets of many industrialized countries. Besides the long-term CO2 sequestration, energy can be chemically stored in form of CO2/CH4/H2 mixtures, for example resulting from excess wind energy. A precise estimation of the impact of such gas mixtures on the mineralogical, geochemical and petrophysical properties of specific reservoirs and caprocks is crucial for site selection and optimization of storage depth. Underground gas storage is increasingly regarded as a technically viable option for meeting environmental targets and the energy demand through storage in form of H2 or CH4, i.e. resulting from excess wind energy. Gas storage in salt caverns is nowadays a mature technology; in regions where favorable geologic structures such as salt diapires are not available, however, gas storage can only be implemented in porous media such as depleted gas and oil reservoirs or suitable saline aquifers. In such settings, a significant amount of in-situ gas components such as CO2, CH4 (and N2) will always be present, making the CO2/CH4/H2 system of particular interest. A precise estimation of the impact of their gas mixtures on the mineralogical, geochemical and petrophysical properties of specific reservoirs and caprocks is therefore crucial for site selection and optimization of storage depth. In the framework of the collaborative research project H2STORE, the feasibility of industrial-scale gas storage in porous media in several potential siliciclastic depleted gas and oil reservoirs or suitable saline aquifers is being investigated by means of experiments and modelling on actual core materials from the evaluated sites. Among them are the Altmark depleted gas reservoir in Saxony-Anhalt and the Ketzin pilot site for CO2 storage in Brandenburg (Germany). Further sites are located in the Molasse basin in South Germany and Austria. In particular, two

  13. Ice Grain Collisions in Comparison: CO$_2$, H$_2$O and their Mixtures

    CERN Document Server

    Musiolik, Grzegorz; Jankowski, Tim; Wurm, Gerhard

    2016-01-01

    Collisions of ice particles play an important role in the formation of planetesimals and comets. In recent work we showed, that CO$_2$ ice behaves like silicates in collisions. The resulting assumption was that it should therefore stick less efficiently than H$_2$O ice. Within this paper a quantification of the latter is presented. We used the same experimental setup to study collisions of pure CO$_2$ ice, pure water ice and 50\\% mixtures by mass between CO$_2$ and water at 80K, 1 mbar and an average particle size of $\\sim 90 \\mu$m. The results show a strong increase of the threshold velocity between sticking and bouncing with increasing water content. This supports the idea that water ice is favorable for early growth phases of planets in a zone within the H$_2$O and the CO$_2$ iceline.

  14. Extra-terrestrial sprites: laboratory investigations in planetary gas mixtures

    NARCIS (Netherlands)

    D. Dubrovin; Y. Yair; C. Price; S. Nijdam (Sander); T.T.J. Clevis; E.M. van Veldhuizen; U. Ebert (Ute)

    2012-01-01

    textabstractWe investigate streamers in gas mixtures representing the atmospheres of Jupiter, Saturn (H2-He) and Venus (CO2-N2). Streamer diameters, velocities, radiance and overall morphology are investigated with fast ICCD camera images. We confirm experimentally the scaling of streamer diameters

  15. H2S Analysis in Biological Samples Using Gas Chromatography with Sulfur Chemiluminescence Detection

    OpenAIRE

    Vitvitsky, Victor; Banerjee, Ruma

    2015-01-01

    Hydrogen sulfide (H2S) is a metabolite and signaling molecule in biological tissues that regulates many physiological processes. Reliable and sensitive methods for H2S analysis are necessary for a better understanding of H2S biology and for the pharmacological modulation of H2S levels in vivo. In this chapter, we describe the use of gas chromatography coupled to sulfur chemiluminescence detection to measure the rates of H2S production and degradation by tissue homogenates at physiologically r...

  16. Laser-induced spark ignition of H2/O2/Ar mixtures

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Laser-induced spark ignition of hydrogen-oxygen-argon mixtures was experimentally investigated using a Q-swiched Nd:YAG laser to break down the gas at 532 nm. The laser-based high-speed schlieren system was employed to record flame front evolution for the gas mixtures with different initial pressure or laser output energy or argon dilution. The results show that the breakdown of the gas leads to the generation of ellipsoidal plasma. The rarefaction waves create the toroidal rings at the leading and trailing edges of the plasma, which provides a reasonable explanation for inward wrinkle of the plasma and the resultant flame. The toroidal rings at leading edge decays more rapidly and a gas lobe is generated that moves towards the laser. The hot gas in the plasma induces the generation of the spark kernel. Affected by the very weak shock wave or compression waves reflected off the wall, the initial laminar flame decelerates. The arc flame front interactions with the wall, reversed shock wave or compression waves, rarefaction waves, etc. induce the transition from laminar flame to turbulent one. These induce the transition from laminar flame to turbulent flame. For stoichiometric hydrogen-oxygen mixtures diluted by 76.92% argon at an initial pressure of 53.33 kPa, the minimum output energy of the laser is 15 mJ for successful laser-induced spark ignition. With increasing initial pressure or the output energy of the laser, or decreasing argon dilution, the speed of the flame front increases.

  17. Update on DOE Advanced IGCC/H2 Gas Turbine

    Science.gov (United States)

    Chupp, Ray

    2009-01-01

    Cooling Flow Reduction: a) Focus on improving turbine hot gas path part cooling efficiency. b) Applicable to current metallic turbine components and synergistic with advanced materials. c) Address challenges of IGCC/hydrogen fuel environment (for example, possible cooling hole plugging). Leakage Flow Reduction: a) Focus on decreasing turbine parasitic leakages, i.e. between static-to-static, static-to-rotating turbine parts. b) Develop improved seal designs in a variety of important areas. Purge Flow Reduction: a) Focus on decreasing required flows to keep rotor disk cavities within temperature limits. b) Develop improved sealing at the cavity rims and modified flow geometries to minimize hot gas ingestion and aerodynamic impact.

  18. Monte Carlo simulations of high-pressure phase equilibria of CO2-H2O mixtures.

    Science.gov (United States)

    Liu, Yang; Panagiotopoulos, Athanassios Z; Debenedetti, Pablo G

    2011-05-26

    Histogram-reweighting grand canonical Monte Carlo simulations were used to obtain the phase behavior of CO(2)-H(2)O mixtures over a broad temperature and pressure range (50 °C ≤ T ≤ 350 °C, 0 ≤ P ≤ 1000 bar). We performed a comprehensive test of several existing water (SPC, TIP4P, TIP4P2005, and exponential-6) and carbon dioxide (EPM2, TraPPE, and exponential-6) models using conventional Lorentz-Berthelot combining rules for the unlike-pair parameters. None of the models we studied reproduce adequately experimental data over the entire temperature and pressure range, but critical assessments were made on the range of T and P where particular model pairs perform better. Away from the critical region (T ≤ 250 °C), the exponential-6 model combination yields the best predictions for the CO(2)-rich phase, whereas the TraPPE/TIP4P2005 model combination provides the most accurate coexistence composition and pressure for the H(2)O-rich phase. Near the critical region (250 °C < T ≤ 350 °C), the critical points are not accurately estimated by any of the models studied, but the exponential-6 models are able to qualitatively capture the critical loci and the shape of the phase envelopes. Local improvements can be achieved at specific temperatures by introducing modification factors to the Lorentz-Berthelot combining rules, but the modified combining rule is still not able to achieve global improvements over the entire temperature and pressure range. Our work points to the challenge and importance of improving current atomistic models so as to accurately predict the phase behavior of this important binary mixture.

  19. On thermal conductivity of gas mixtures containing hydrogen

    Science.gov (United States)

    Zhukov, Victor P.; Pätz, Markus

    2016-12-01

    A brief review of formulas used for the thermal conductivity of gas mixtures in CFD simulations of rocket combustion chambers is carried out in the present work. In most cases, the transport properties of mixtures are calculated from the properties of individual components using special mixing rules. The analysis of different mixing rules starts from basic equations and ends by very complex semi-empirical expressions. The formulas for the thermal conductivity are taken for the analysis from the works on modelling of rocket combustion chambers. H_2- O_2 mixtures are chosen for the evaluation of the accuracy of the considered mixing rules. The analysis shows that two of them, of Mathur et al. (Mol Phys 12(6):569-579, 1967), and of Mason and Saxena (Phys Fluids 1(5):361-369, 1958), have better agreement with the experimental data than other equations for the thermal conductivity of multicomponent gas mixtures.

  20. On thermal conductivity of gas mixtures containing hydrogen

    Science.gov (United States)

    Zhukov, Victor P.; Pätz, Markus

    2017-06-01

    A brief review of formulas used for the thermal conductivity of gas mixtures in CFD simulations of rocket combustion chambers is carried out in the present work. In most cases, the transport properties of mixtures are calculated from the properties of individual components using special mixing rules. The analysis of different mixing rules starts from basic equations and ends by very complex semi-empirical expressions. The formulas for the thermal conductivity are taken for the analysis from the works on modelling of rocket combustion chambers. \\hbox {H}_2{-}\\hbox {O}_2 mixtures are chosen for the evaluation of the accuracy of the considered mixing rules. The analysis shows that two of them, of Mathur et al. (Mol Phys 12(6):569-579, 1967), and of Mason and Saxena (Phys Fluids 1(5):361-369, 1958), have better agreement with the experimental data than other equations for the thermal conductivity of multicomponent gas mixtures.

  1. Dynamic quantum molecular sieving separation of D2 from H2-D2 mixture with nanoporous materials.

    Science.gov (United States)

    Niimura, Subaru; Fujimori, Toshihiko; Minami, Daiki; Hattori, Yoshiyuki; Abrams, Lloyd; Corbin, Dave; Hata, Kenji; Kaneko, Katsumi

    2012-11-14

    Quantum molecular sieving separability of D(2) from an H(2)-D(2) mixture was measured at 77 K for activated carbon fiber, carbon molecular sieve, zeolite and single wall carbon nanotube using a flow method. The amount of adsorbed D(2) was evidently larger than H(2) for all samples. The maximum adsorption ratio difference between D(2) and H(2) was 40% for zeolite (MS13X), yielding a selectivity for D(2) with respect to H(2) of 3.05.

  2. Comparing gas-phase and grain-catalyzed H2 formation

    CERN Document Server

    Glover, S C O

    2003-01-01

    Because H2 formation on dust grain surfaces completely dominates gas-phase H2 formation in local molecular clouds, it is often assumed that gas-phase formation is never important. In fact, it is the dominant mechanism in a number of cases. In this paper, I briefly summarize the chemistry of gas-phase H2 formation, and show that it dominates for dust-to-gas ratios less than a critical value D_cr. I also show that D_cr is simple to calculate for any given astrophysical situation, and illustrate this with a number of examples, ranging from H2 formation in warm atomic gas in the Milky Way to the formation of protogalaxies at high redshift.

  3. H2S Analysis in Biological Samples Using Gas Chromatography with Sulfur Chemiluminescence Detection

    Science.gov (United States)

    Vitvitsky, Victor; Banerjee, Ruma

    2015-01-01

    Hydrogen sulfide (H2S) is a metabolite and signaling molecule in biological tissues that regulates many physiological processes. Reliable and sensitive methods for H2S analysis are necessary for a better understanding of H2S biology and for the pharmacological modulation of H2S levels in vivo. In this chapter, we describe the use of gas chromatography coupled to sulfur chemiluminescence detection to measure the rates of H2S production and degradation by tissue homogenates at physiologically relevant concentrations of substrates. This method allows separation of H2S from other sulfur compounds and provides sensitivity of detection to ~15 pg (or 0.5 pmol) of H2S per injected sample. PMID:25725519

  4. Extra-terrestrial sprites: laboratory investigations in planetary gas mixtures

    OpenAIRE

    Dubrovin, D.; Y. Yair; Price, C; Nijdam, Sander; Clevis, T. T. J.; Veldhuizen, van, H.T.; Ebert, Ute

    2012-01-01

    We investigate streamers in gas mixtures representing the atmospheres of Jupiter, Saturn (H2-He) and Venus (CO2-N2). Streamer diameters, velocities, radiance and overall morphology are investigated with fast ICCD camera images. We confirm experimentally the scaling of streamer diameters in these gases by studying streamers with minimal diameters. The brightness of laboratory streamers is investigated, and a scaling model for atmospheric sprites is proposed. Fitting the scaling model with meas...

  5. HD and H2 formation in low-metallicity dusty gas clouds at high reshift

    CERN Document Server

    Cazaux, S

    2009-01-01

    Context: The HD and H2 molecules play important roles in the cooling of primordial and very metal-poor gas at high redshift. Aims: Grain surface and gas phase formation of HD and H2 is investigated to assess the importance of trace amounts of dust, 10^{-5}-10^{-3} Zo, in the production of HD and H2. Methods: We consider carbonaceous and silicate grains and include both physisorption and chemisorption, tunneling, and realistic grain surface barriers. We find, for a collapsing gas cloud environment with coupled chemical and thermal balance, that dust abundances as small as 10^{-5} solar lead to a strong boost in the H2 formation rate due to surface reactions. As a result of this enhancement in H2, HD is formed more efficiently in the gas phase through the D+ +H2 reaction. Direct formation of HD on dust grains cannot compete well with this gas phase process for dust temperatures below 150 K. We also derive up-to-date analytic fitting formulae for the grain surface formation of H2 and HD, including the different ...

  6. 30 CFR 250.1164 - What are the requirements for flaring or venting gas containing H2S?

    Science.gov (United States)

    2010-07-01

    ... Gas Production Requirements Flaring, Venting, and Burning Hydrocarbons § 250.1164 What are the requirements for flaring or venting gas containing H2S? (a) You may not vent gas containing H2S, except for... Supervisor may further restrict the flaring of gas containing H2S. The Regional Supervisor will use...

  7. Origins of High H2S-bearing Natural Gas in China

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Natural gas containing hydrogen sulphide (H2S) has been found in several petroliferous basins in China, such as the Sichuan Basin, Bohai Bay Basin, Ordos Basin, Tarim Basin, etc. Natural gas with higher H2S contents (H2S >5% mol.) is mostly distributed in both the gas reservoirs of Dukouhe, Luojiazhai, Puguang and Tieshanpo, which belong to the Triassic Feixianguan Formation in the northeastern Sichuan Basin and those of the Kongdian-Shahejie formations in the northeastern Jinxian Sag of the Jizhong Depression, Bohai Bay Basin. In the Sichuan Basin, the H2S contents of natural gas average over 9% and some can be 17 %, while those of the Bohai Bay Basin range from 40 % to 92 %, being then one of the gas reservoirs with the highest H2S contents in the world. Based on detailed observation and sample analysis results of a total 5000 m of core from over 70 wells in the above-mentioned two basins, especially sulfur isotopic analysis of gypsum,brimstone, pyrite and natural gas, also with integrated study of the geochemical characteristics of hydrocarbons, it is thought that the natural gas with high H2S contents resulted from thermochemical sulfate reduction (TSR) reactions.Among them, the natural gas in the Feixianguan Formation resulted from TSR reactions participated by hydrocarbon gas,while that in the Zhaolanzhuang of the Jinxian Sag being the product of TSR participated by crude oil. During the consumption process of hydrocarbons due to TSR, the heavy hydrocarbons were apt to react with sulfate, which accordingly resulted in the dry coefficient of natural gas increasing and the carbon isotopes becoming heavier.

  8. C+/H2 gas in star-forming clouds and galaxies

    Science.gov (United States)

    Nordon, Raanan; Sternberg, Amiel

    2016-11-01

    We present analytic theory for the total column density of singly ionized carbon (C+) in the optically thick photon dominated regions (PDRs) of far-UV irradiated (star-forming) molecular clouds. We derive a simple formula for the C+ column as a function of the cloud (hydrogen) density, the far-UV field intensity, and metallicity, encompassing the wide range of galaxy conditions. When assuming the typical relation between UV and density in the cold neutral medium, the C+ column becomes a function of the metallicity alone. We verify our analysis with detailed numerical PDR models. For optically thick gas, most of the C+ column is mixed with hydrogen that is primarily molecular (H2), and this `C+/H2' gas layer accounts for almost all of the `CO-dark' molecular gas in PDRs. The C+/H2 column density is limited by dust shielding and is inversely proportional to the metallicity down to ˜0.1 solar. At lower metallicities, H2 line blocking dominates and the C+/H2 column saturates. Applying our theory to CO surveys in low-redshift spirals, we estimate the fraction of C+/H2 gas out of the total molecular gas to be typically ˜0.4. At redshifts 1 < z < 3 in massive disc galaxies the C+/H2 gas represents a very small fraction of the total molecular gas (≲ 0.16). This small fraction at high redshifts is due to the high gas surface densities when compared to local galaxies.

  9. Lighting the dark molecular gas: H$_{2}$ as a direct tracer

    CERN Document Server

    Togi, Aditya

    2016-01-01

    Robust knowledge of molecular gas mass is critical for understanding star formation in galaxies. The H$_{2}$ molecule does not emit efficiently in the cold interstellar medium, hence the molecular gas content of galaxies is typically inferred using indirect tracers. At low metallicity and in other extreme environments, these tracers can be subject to substantial biases. We present a new method of estimating total molecular gas mass in galaxies directly from pure mid-infrared rotational H$_{2}$ emission. By assuming a power-law distribution of H$_{2}$ rotational temperatures, we can accurately model H$_{2}$ excitation and reliably obtain warm ($T\\!\\gtrsim\\!100$ K) H$_{2}$ gas masses by varying only the power law's slope. With sensitivities typical of Spitzer/IRS, we are able to directly probe the H$_{2}$ content via rotational emission down to ~80 K, accounting for ~15% of the total molecular gas mass in a galaxy. By extrapolating the fitted power law temperature distributions to a calibrated \\emph{single} low...

  10. Study of H2S increasing in gas production of vapor continuous injection

    Energy Technology Data Exchange (ETDEWEB)

    Centeno, J. [PDVSA INTEVEP (Venezuela)

    2011-07-01

    In the heavy oil industry, thermal recovery methods are often used to enhance oil recovery, continuous vapor injection is one of them. In this method, water vapor is injected into the reservoir at high temperatures, affecting the geochemical system of the fluid reservoir. It has been noticed that the use of the continuous vapor injection method results in increased concentrations of H2S in gas production. Previous studies proved that H2S diffusion is affected by the H2S/CO2 ratio and this paper aimed at determining the influence of such ratios on the diffusion properties of acid gases. Experiments were conducted with three different H2S/CO2 ratios and heavy oil samples from Orinoco oil elt. Results showed that acid gas diffusion decreases when the H2S/CO2 ratio increases and that the diffusion of H2S is better with a high percentage of water. This study successfully assessed the variation of acid gas diffusion with different values of H2S/CO2 ratios and water percentages.

  11. Preparation of azo polyelectrolyte self-assembled multilayers by using N,N-dimethylformamide/H2O mixtures as solvents

    Institute of Scientific and Technical Information of China (English)

    Tuo Xinlin; Chen Di; Wang Xiaogong

    2006-01-01

    N,N-Dimethylformamide (DMF)/H2O mixtures were used as solvents to fabricate azo polyelectrolyte (PEAPH)/poly(diallyldimethyl ammonium chloride)(PDAC)self-assembled multilayers with the layer-by-layer electrostatic adsorption technique.PEAPH is a copolymer of acrylic acid and azobenzene-containing acrylate.The effect of the ratio of DMF to water on the .multilayer growth,structure and surface morphology was studied in some details.Results show that DMF/H2O mixtures are proper media for PEAPH/PDAC multilayer fabrication.The ratio of DMF to water in the mixture has significant influence on the multilayer structure and surface morphology.With the increase of DMF content,the multilayer thickness has a better linear growth relationship with the bilayer number,and the multilayer surface becomes smoother.Moreover,azo chromophores show less H-aggregation when the multilayers are fabricated from DMF/H2O mixtures with higher DMF contents.These studies demonstrate that using organic solvent and water mixtures is an effective way to control the multilayer construction by adjusting the media properties.This method can be applied to multilayer fabrication of other water-insoluble polyelectrolytes.

  12. Lighting the Dark Molecular Gas: H2 as a Direct Tracer

    Science.gov (United States)

    Togi, Aditya; Smith, J. D. T.

    2016-10-01

    Robust knowledge of molecular gas mass is critical for understanding star formation in galaxies. The {{{H}}}2 molecule does not emit efficiently in the cold interstellar medium, hence the molecular gas content of galaxies is typically inferred using indirect tracers. At low metallicity and in other extreme environments, these tracers can be subject to substantial biases. We present a new method of estimating total molecular gas mass in galaxies directly from pure mid-infrared rotational {{{H}}}2 emission. By assuming a power-law distribution of {{{H}}}2 rotational temperatures, we can accurately model {{{H}}}2 excitation and reliably obtain warm (T ≳ 100 K) {{{H}}}2 gas masses by varying only the power law’s slope. With sensitivities typical of Spitzer/IRS, we are able to directly probe the {{{H}}}2 content via rotational emission down to ∼80 K, accounting for ∼15% of the total molecular gas mass in a galaxy. By extrapolating the fitted power-law temperature distributions to a calibrated single lower cutoff temperature, the model also recovers the total molecular content within a factor of ∼2.2 in a diverse sample of galaxies, and a subset of broken power-law models performs similarly well. In ULIRGs, the fraction of warm {{{H}}}2 gas rises with dust temperature, with some dependency on α CO. In a sample of five low-metallicity galaxies ranging down to 12+{log}[{{O}}/{{H}}]=7.8, the model yields molecular masses up to ∼100× larger than implied by CO, in good agreement with other methods based on dust mass and star formation depletion timescale. This technique offers real promise for assessing molecular content in the early universe where CO and dust-based methods may fail.

  13. Dense Molecular Gas and H2O Maser Emission in Galaxies

    Indian Academy of Sciences (India)

    F. Huang; J. S. Zhang; R. M. Li; H. K. Li

    2014-09-01

    Extragalactic H2O masers have been found in dense gas circumstance in off-nuclear star formation regions or within parsecs of Active Galactic Nuclei (AGNs). HCN molecular (one of the best dense gas tracers) Emission has been detected in more than 60 galaxies. For HCN-detected galaxy sample, the relation of maser and gas emission was investigated here to identify physical observable properties that differentiate maser and non-maser galaxies. Our analysis results show that there is no significant difference on the infrared and gas emission between maser galaxies and galaxies without maser detection. For maser host HCN-galaxies, maser luminosity is found to be correlated to CO luminosity (a proxy of the total molecular gas) and HCN luminosity, i.e., kilomasers (H2O < 10⊙) with low maser luminosity having low gas emission luminosity, with respect to megamasers (H2O > 10⊙). For normalized maser and HCN luminosity (for removing distance effect), the correlation is still apparent. However, for normalized maser and CO luminosity, the correlation disappeared completely. Thus one proposition that the amount of dense molecular gas should be a good tracer of H2O maser emission can be made.

  14. A thermodynamical model for the surface tension of silicate melts in contact with H2O gas

    Science.gov (United States)

    Colucci, Simone; Battaglia, Maurizio; Trigila, Raffaello

    2016-01-01

    Surface tension plays an important role in the nucleation of H2O gas bubbles in magmatic melts and in the time-dependent rheology of bubble-bearing magmas. Despite several experimental studies, a physics based model of the surface tension of magmatic melts in contact with H2O is lacking. This paper employs gradient theory to develop a thermodynamical model of equilibrium surface tension of silicate melts in contact with H2O gas at low to moderate pressures. In the last decades, this approach has been successfully applied in studies of industrial mixtures but never to magmatic systems. We calibrate and verify the model against literature experimental data, obtained by the pendant drop method, and by inverting bubble nucleation experiments using the Classical Nucleation Theory (CNT). Our model reproduces the systematic decrease in surface tension with increased H2O pressure observed in the experiments. On the other hand, the effect of temperature is confirmed by the experiments only at high pressure. At atmospheric pressure, the model shows a decrease of surface tension with temperature. This is in contrast with a number of experimental observations and could be related to microstructural effects that cannot be reproduced by our model. Finally, our analysis indicates that the surface tension measured inverting the CNT may be lower than the value measured by the pendant drop method, most likely because of changes in surface tension controlled by the supersaturation.

  15. Nitrocarburising in ammonia-hydrocarbon gas mixtures

    DEFF Research Database (Denmark)

    Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

    2010-01-01

    The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammoniapropene- hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

  16. Nitrocarburizing in ammonia-hydrocarbon gas mixtures

    DEFF Research Database (Denmark)

    Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

    2011-01-01

    The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammonia-propene-hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

  17. Formation of H2-He Substellar Bodies in Cold Conditions: Gravitational Stability of Binary Mixtures in a Phase Transition

    CERN Document Server

    Füglistaler, Andreas

    2015-01-01

    Molecular clouds consist typically of 3/4 H2, 1/4 He and traces of heavier elements. In an earlier work we showed that at very low temperatures and high densities, H2 can be in a phase transition leading to the formation of ice clumps as large as comets, or even planets. However, He has very different chemical properties and no phase transition is expected before H2 in dense ISM conditions. The gravitational stability of fluid mixtures has been studied before, but not including a phase transition. We study the gravitational stability of binary fluid mixtures with special emphasis if one component is in a phase transition. The results are aimed at applications in molecular cloud conditions. We study the gravitational stability of van der Waals fluid mixtures using linearised analysis and examine virial equilibrium conditions using the Lennard-Jones inter-molecular potential. Then, combining the Lennard-Jones and gravitational potentials, the non-linear dynamics of fluid mixtures are studied using the molecular...

  18. Modeling the phase behavior of H2S+n-alkane binary mixtures using the SAFT-VR+D approach.

    Science.gov (United States)

    dos Ramos, M Carolina; Goff, Kimberly D; Zhao, Honggang; McCabe, Clare

    2008-08-07

    A statistical associating fluid theory for potential of variable range has been recently developed to model dipolar fluids (SAFT-VR+D) [Zhao and McCabe, J. Chem. Phys. 2006, 125, 104504]. The SAFT-VR+D equation explicitly accounts for dipolar interactions and their effect on the thermodynamics and structure of a fluid by using the generalized mean spherical approximation (GMSA) to describe a reference fluid of dipolar square-well segments. In this work, we apply the SAFT-VR+D approach to real mixtures of dipolar fluids. In particular, we examine the high-pressure phase diagram of hydrogen sulfide+n-alkane binary mixtures. Hydrogen sulfide is modeled as an associating spherical molecule with four off-center sites to mimic hydrogen bonding and an embedded dipole moment (micro) to describe the polarity of H2S. The n-alkane molecules are modeled as spherical segments tangentially bonded together to form chains of length m, as in the original SAFT-VR approach. By using simple Lorentz-Berthelot combining rules, the theoretical predictions from the SAFT-VR+D equation are found to be in excellent overall agreement with experimental data. In particular, the theory is able to accurately describe the different types of phase behavior observed for these mixtures as the molecular weight of the alkane is varied: type III phase behavior, according to the scheme of classification by Scott and Konynenburg, for the H2S+methane system, type IIA (with the presence of azeotropy) for the H2S+ethane and+propane mixtures; and type I phase behavior for mixtures of H2S and longer n-alkanes up to n-decane. The theory is also able to predict in a qualitative manner the solubility of hydrogen sulfide in heavy n-alkanes.

  19. Synthesis of activated carbon from oil fly ash for removal of H2S from gas stream

    Science.gov (United States)

    Aslam, Zaheer; Shawabkeh, Reyad A.; Hussein, Ibnelwaleed A.; Al-Baghli, Nadhir; Eic, Mladen

    2015-02-01

    Activated carbon (AC) is made from waste oil fly ash (OFA) which is produced in large quantities from power generation plants through combustion of heavy fuel oil. OFA contains ∼80% carbon that makes it suitable for producing AC by physicochemical treatments using a mixture of HNO3, H2SO4, and H3PO4 acids to remove non-carbonaceous impurities. The acid treated OFA is then activated by CO2 at 990 °C. The physico-chemical treatments of OFA have increased the surface area from 4 to 375 m2/g. Surface morphology and pore volume of AC are characterized by combined SEM and EDX techniques. Elemental analysis shows that sulfur content is reduced from 7.1 wt% in untreated OFA to 0.51 wt% for the treated OFA. The AC is further treated with HNO3 and NH4OH solutions in order to attach the carboxylic and amine groups on the surface, respectively. FTIR characterization is used to confirm the presence of the functional groups on the surface of AC at different stages of its development. The performance of functionalized AC samples is tested for the removal of H2S from a synthetic natural gas by carrying out breakthrough experiments. The results from these tests have shown maximum adsorption capacity of 0.3001 mg/g for NH4OH functionalized activated carbon with 86.43% regeneration efficiency. The ammonium hydroxide treated AC is found to be more effective for H2S removal than acid treated AC as confirmed by breakthrough experiments. The results indicate that the presence of more acidic functionalities on the surface reduces the H2S adsorption efficiency from the gas mixture.

  20. A discussion on gas sources of the Feixianguan Formation H2S-rich giant gas fields in the northeastern Sichuan Basin

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In recent years several H2S-rich oolite giant gas pools have been discovered in the Lower Triassic Feixianguan Formation of the northeastern Sichuan basin, and their explored gas reserves have been over 5000x108 m3. However, gas sources remain unsolved due to multiple source horizons with high maturity in this area and TSR alterations. By integrating analytical data of natural gas samples with conprehensive investigations on many factors, such as oil-gas geology, distribution and evolution of source rocks, charging and adjustment of gas pools, mixture of natural gases and secondery alterations, the present study concluded that the dominant source for the Feixianguan Fr. gas pools is the Permian Longtan Fr. source rock and secondly the Silurian Longmaxi Fr. source rock. Natural gases from the various gas pools differ genetically due to the matching diversity of seal configurations with phases of hydrocarbon generation and expulsion by different source rocks, among which natural gases in Puguang Gasfield are dominated by the trapped gas generated from the Longtan Fr. source rock and commingled with the gas cracked from the Silurian crude oil, while those in Dukouhe,Tieshangpo and Luojiazhai Gasfields are composed mainly of the Silurian oil-cracking gas and commingled with the natural gas derived from the Longtan Fr. source rock.

  1. Time-resolved electron temperature and electron density measurements in a nanosecond pulse filament discharge in H2-He and O2-He mixtures

    Science.gov (United States)

    Roettgen, A.; Shkurenkov, I.; Simeni Simeni, M.; Adamovich, I. V.; Lempert, W. R.

    2016-10-01

    Time evolution of electron density and electron temperature in a nanosecond pulse, diffuse filament electric discharge in H2-He and O2-He mixtures at a pressure of 100 Torr is studied by Thomson/pure rotational Raman scattering and kinetic modeling. The discharge is sustained between two spherical electrodes separated by a 1 cm gap and powered by high voltage pulses ~150 ns duration. Discharge energy coupled to the plasma filament 2-3 mm in diameter is 4-5 mJ/pulse, with specific energy loading of up to ~0.3 eV/molecule. At all experimental conditions, a rapid initial rise of electron temperature and electron density during the discharge pulse is observed, followed by the decay in the afterglow, over ~100 ns-1 µs. Electron density in the afterglow decays more rapidly as H2 or O2 fraction in the mixture is increased. In He/H2 mixtures, this is likely due to more rapid recombination of electrons in collisions with \\text{H}2+ and \\text{H}3+ ions, compared to recombination with \\text{He}2+ ions. In O2/He mixtures, electron density decay in the afterglow is affected by recombination with \\text{O}2+ and \\text{O}4+ ions, while the effect of three-body attachment is relatively minor. Peak electron number densities and electron temperatures are n e  =  (1.7-3.1) · 1014 cm-3 and T e  =  2.9-5.5 eV, depending on gas mixture composition. Electron temperature in the afterglow decays to approximately T e  ≈  0.3 eV, considerably higher compared to the gas temperature of T  =  300-380 K, inferred from O2 pure rotational Raman scattering spectra, due to superelastic collisions. The experimental results in helium and O2-He mixtures are compared with kinetic modeling predictions, showing good agreement.

  2. Hydrogen bonding and π-π stacking in nicotinamide/H2O mixtures

    Science.gov (United States)

    Zhai, Cuiping; Zhang, Ping; Peng, Peng; Hou, Bingbing; Li, Lina

    2017-09-01

    The interactions between nicotinamide (NA) and H2O were studied using UV-visible spectra (UV-Vis), cyclic voltammetry (CV), nuclear magnetic resonance (NMR), density functional theory (DFT) and atoms in molecules (AIM) analysis. According to the changes of the UV-Vis spectra and the oxidation and reduction potentials in cyclic voltammograms of NA in aqueous solution, it was found that hydrogen bonding occurred between NA and H2O molecules. Quantum chemistry calculations and AIM analysis further confirmed the existence of hydrogen bonding between H2O molecules and the amide group, the nitrogen atom, and hydrogen atoms on the pyridine ring of NA molecules. In addition, the NMR results demonstrated that the π-π stacking between NA pyridine rings could be formed at higher concentrations.

  3. Interactions of Multiple Gas-Transducing Systems: Hallmarks and Uncertainties of CO, NO, and H2S Gas Biology

    Science.gov (United States)

    Fukuda, Ryo; Bateman, Ryon M.; Yamamoto, Takehiro

    2010-01-01

    Abstract The diverse physiological actions of the “biologic gases,” O2, CO, NO, and H2S, have attracted much interest. Initially viewed as toxic substances, CO, NO, and H2S play important roles as signaling molecules. The multiplicity of gas actions and gas targets and the difficulty in measuring local gas concentrations obscures detailed mechanisms whereby gases exert their actions, and many questions remain unanswered. It is now readily apparent, however, that heme-based proteins play central roles in gas-generation/reception mechanisms and provide a point where multiple gases can interact. In this review, we consider a number of key issues related to “gas biology,” including the effective tissue concentrations of these gases and the importance and significance of the physical proximity of gas-producing and gas-receptor/sensors. We also take an integrated approach to the interaction of gases by considering the physiological significance of CO, NO, and H2S on mitochondrial cytochrome c oxidase, a key target and central mediator of mitochondrial respiration. Additionally, we consider the effects of biologic gases on mitochondrial biogenesis and “suspended animation.” By evaluating gas-mediated control functions from both in vitro and in vivo perspectives, we hope to elaborate on the complex multiple interactions of O2, NO, CO, and H2S. Antioxid. Redox Signal. 13, 157–192. PMID:19939208

  4. Metal organic framework absorbent platforms for removal of co2 and h2s from natural gas

    KAUST Repository

    Belmabkhout, Youssef

    2016-10-13

    Provided herein are metal organic frameworks comprising metal nodes and N-donor organic ligands which have high selectivity and stability in the present of gases and vapors including H2S, H2O, and CO2. Methods include capturing one or more of H2S, H2O, and CO2 from fluid compositions, such as natural gas.

  5. U^{28+}-intensity record applying a H_{2}-gas stripper cell

    Directory of Open Access Journals (Sweden)

    Winfried Barth

    2015-04-01

    Full Text Available To meet the Facility for Antiproton and Ion Research science requirements higher beam intensity has to be achieved in the present GSI-accelerator complex. For this an advanced upgrade program for the UNILAC is ongoing. Stripping is a key technology for all heavy ion accelerators. For this an extensive research and development program was carried out to optimize for high brilliance heavy ion operation. After upgrade of the supersonic N_{2}-gas jet (2007, implementation of high current foil stripping (2011 and preliminary investigation of H_{2}-gas jet operation (2012, recently (2014 a new H_{2}-gas cell using a pulsed gas regime synchronized with arrival of the beam pulse has been developed. An obviously enhanced stripper gas density as well as a simultaneously reduced gas load for the pumping system result in an increased stripping efficiency, while the beam emittance remains the same. A new record intensity (7.8 emA for ^{238}U^{28+} beams at 1.4  MeV/u has been achieved applying the pulsed high density H_{2} stripper target to a high intensity ^{238}U^{4+} beam from the VARIS ion source with a newly developed extraction system. The experimental results are presented in detail.

  6. U2 8 + -intensity record applying a H2 -gas stripper cell

    Science.gov (United States)

    Barth, Winfried; Adonin, Aleksey; Düllmann, Christoph E.; Heilmann, Manuel; Hollinger, Ralph; Jäger, Egon; Khuyagbaatar, Jadambaa; Krier, Joerg; Scharrer, Paul; Vormann, Hartmut; Yakushev, Alexander

    2015-04-01

    To meet the Facility for Antiproton and Ion Research science requirements higher beam intensity has to be achieved in the present GSI-accelerator complex. For this an advanced upgrade program for the UNILAC is ongoing. Stripping is a key technology for all heavy ion accelerators. For this an extensive research and development program was carried out to optimize for high brilliance heavy ion operation. After upgrade of the supersonic N2 -gas jet (2007), implementation of high current foil stripping (2011) and preliminary investigation of H2 -gas jet operation (2012), recently (2014) a new H2 -gas cell using a pulsed gas regime synchronized with arrival of the beam pulse has been developed. An obviously enhanced stripper gas density as well as a simultaneously reduced gas load for the pumping system result in an increased stripping efficiency, while the beam emittance remains the same. A new record intensity (7.8 emA) for 238U2 8 + beams at 1.4 MeV /u has been achieved applying the pulsed high density H2 stripper target to a high intensity 238U4 + beam from the VARIS ion source with a newly developed extraction system. The experimental results are presented in detail.

  7. Modeling Water Saturation Points in Natural Gas Streams Containing CO2 and H2S-Comparisons with Different Equations of State

    DEFF Research Database (Denmark)

    dos Santos, Leticia C.; Abunahman, Samir S.; Tavares, Frederico W.

    2015-01-01

    Since the discovery of the Pre-Salt layer in Brazilian waters, production of high gas-oil ratio (GOR) has increased considerably. This gas has a high content of water, CO2, and sometimes H2S. A study in different conditions was conducted using several equations of state (EoS) such as Peng...... to be used for predicting dew points for water-containing mixtures, especially at high pressures....

  8. Computational exploration of H2S/CH4 mixture separation using acid-functionalized UiO-66(Zr) membrane and composites☆

    Institute of Scientific and Technical Information of China (English)

    Shumeng Wang; Dong Wu; Hongliang Huang; Qingyuan Yang; Minman Tong; Dahuan Liu; Chongli Zhong

    2015-01-01

    A computational study was firstly performed in this work to examine the applicability of an acid-functionalized metal-organic framework (MOF), UiO-66(Zr)-(COOH)2, in membrane-based H2S/CH4 separation. The results show that this MOF could be potentially interesting when being used as the pure membrane material for the sep-aration of the mixture with low H2S concentration. Further, the performance of 10 different mixed matrix mem-branes (MMMs) on the basis of the MOF was predicted by combing the molecular simulation data and the Maxwel permeation model. The results indicate that using this MOF as filler particles in MMMs can significantly enhance the permeation performance of pure polymers. The findings obtained in this work may be helpful in fa-cilitating the application of this promising MOF for practical desulfurization process of fuel gas.

  9. Intramolecular bond length dependence of the anisotropic dispersion coefficients for H2-rare gas interactions

    Science.gov (United States)

    Wormer, Paul E. S.; Hettema, Hinne; Thakkar, Ajit J.

    1993-05-01

    Effective states arising from variational perturbation calculations in a full configuration interaction basis are used to calculate dynamic multipole polarizabilities for H2 at seven different bond lengths. These are combined with previously calculated dynamic polarizabilities for rare gas atoms to obtain the intramolecular bond length dependence of the anisotropic C6, C8, and C10 dispersion coefficients for H2-X (X=He, Ne, Ar, Kr, Xe) interactions. The results are generally in good agreement with previous semiempirical estimates where available.

  10. A breakthrough in flue gas cleanup, CO2 mitigation and H2S removal

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Wolf; Wasas, James; Stenger, Raymond; Howell, Evan

    2010-09-15

    SWAPSOL Corp. is developing commercial processes around a newly discovered reaction that reduces H2S below detectable levels while reacting with CO2 to form water, sulfur and carsuls, a carbon-sulfur polymer. The Stenger-Wasas Process (SWAP) stands to simplify sulfur removal technology as it consumes CO2 in an exothermic reaction. The SWAP has applications in landfill, sour, flue and Claus tail gas cleanup and may replace Claus technology. Destruction of waste hydrocarbons provides a source of H2S. The primary reactions and variants have been independently verified and the chemical kinetics determined by a third party laboratory.

  11. A breakthrough in flue gas cleanup, CO2 mitigation and H2S removal

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Wolf; Wasas, James; Stenger, Raymond; Howell, Evan

    2010-09-15

    SWAPSOL Corp. is developing commercial processes around a newly discovered reaction that reduces H2S below detectable levels while reacting with CO2 to form water, sulfur and carsuls, a carbon-sulfur polymer. The Stenger-Wasas Process (SWAP) stands to simplify sulfur removal technology as it consumes CO2 in an exothermic reaction. The SWAP has applications in landfill, sour, flue and Claus tail gas cleanup and may replace Claus technology. Destruction of waste hydrocarbons provides a source of H2S. The primary reactions and variants have been independently verified and the chemical kinetics determined by a third party laboratory.

  12. Acidity Measurements with the Glass Electrode in H2O-D2O Mixtures

    DEFF Research Database (Denmark)

    Mikkelsen, K.; Nielsen, Sigurd Olaf

    1960-01-01

    to variations in the hydrogen-ion concentration in both solvents in the range between 2 x 10 -2 and 2 x 10 -5 M. The acidity determinations involve standardization and storage of the glass electrode in solutions in HzO and subsequent drying of the glass electrode with mercury before immersing it in the 0.5-ml...... the point of view of extrapolating rate data obtained in HzO-DzO mixtures to pure D2O....

  13. Surface abundance change in vacuum ultraviolet photodissociation of CO2 and H2O mixture ices.

    Science.gov (United States)

    Kinugawa, Takashi; Yabushita, Akihiro; Kawasaki, Masahiro; Hama, Tetsuya; Watanabe, Naoki

    2011-09-21

    Photodissociation of amorphous ice films of carbon dioxide and water co-adsorbed at 90 K was carried out at 157 nm using oxygen-16 and -18 isotopomers with a time-of-flight photofragment mass spectrometer. O((3)P(J)) atoms, OH (v = 0) radicals, and CO (v = 0,1) molecules were detected as photofragments. CO is produced directly from the photodissociation of CO(2). Two different adsorption states of CO(2), i.e., physisorbed CO(2) on the surface of amorphous solid water and trapped CO(2) in the pores of the film, are clearly distinguished by the translational and internal energy distributions of the CO molecules. The O atom and OH radical are produced from the photodissociation of H(2)O. Since the absorption cross section of CO(2) is smaller than that of H(2)O at 157 nm, the CO(2) surface abundance is relatively increased after prolonged photoirradiation of the mixed ice film, resulting in the formation of a heterogeneously layered structure in the mixed ice at low temperatures. Astrophysical implications are discussed.

  14. Separation of gas mixtures by supported complexes

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, D.A.; Lilga, M.A.; Hallen, R.T.; Lyke, S.E.

    1986-08-01

    The goal of this program is to determine the feasibility of solvent-dissolved coordination complexes for the separation of gas mixtures under bench-scale conditions. In particular, mixtures such as low-Btu gas are examined for CO and H/sub 2/ separation. Two complexes, Pd/sub 2/(dpm)/sub 2/Br/sub 2/ and Ru(CO)/sub 2/(PPh/sub 3/)/sub 3/, were examined in a bench-scale apparatus for the separation of binary (CO-N/sub 2/ or H/sub 2/-N/sub 2/) and quinary (H/sub 2/, CO, CO/sub 2/, CH/sub 4/, and N/sub 2/) mixtures. The separation of CO-N/sub 2/ was enhanced by the presence of the palladium complex in the 1,1,2-trichloroethane (TCE) solvent, especially at high gas and low liquid rates. The five-component gas mixture separation with the palladium complex in TCE provided quite unexpected results based on physical solubility and chemical coordination. The complex retained CO, while the solvent retained CO/sub 2/, CH/sub 4/, and N/sub 2/ to varying degrees. This allowed the hydrogen content to be enhanced due to its low solubility in TCE and inertness to the complex. Thus, a one-step, hydrogen separation can be achieved from gas mixtures with compositions similar to that of oxygen-blown coal gas. A preliminary economic evaluation of hydrogen separation was made for a system based on the palladium complex. The palladium system has a separation cost of 50 to 60 cents/MSCF with an assumed capital investment of $1.60/MSCF of annual capacity charged at 30% per year. This assumes a 3 to 4 year life for the complex. Starting with a 90% hydrogen feed, PSA separation costs are in the range of 30 to 50 cents/MSCF. The ruthenium complex was not as successful for hydrogen or carbon monoxide separation due to unfavorable kinetics. The palladium complex was found to strip hydrogen gas from H/sub 2/S. The complex could be regenerated with mild oxidants which removed the sulfur as SO/sub 2/. 24 refs., 26 figs., 10 tabs.

  15. The Energetics of Molecular Gas in NGC 891 from H2 and FIR Spectroscopy

    CERN Document Server

    Stacey, G J; Boulanger, F; Wu, Yanling; Combes, F; Higdon, S J U; Smith, J D T; Nikola, T

    2010-01-01

    We have studied the molecular hydrogen energetics of the edge-on spiral galaxy NGC\\,891, using a 34-position map in the lowest three pure rotational H$_2$ lines observed with the Spitzer Infrared Spectrograph. The S(0), S(1), and S(2) lines are bright with an extinction corrected total luminosity of $\\sim2.8 \\times 10^{7}$ L$_{\\odot}$, or 0.09\\% of the total-infrared luminosity of NGC\\,891. The H$_2$ line ratios are nearly constant along the plane of the galaxy -- we do not observe the previously reported strong drop-off in the S(1)/S(0) line intensity ratio in the outer regions of the galaxy, so we find no evidence for the very massive cold CO-free molecular clouds invoked to explain the past observations. The H$_2$ level excitation temperatures increase monotonically indicating more than one component to the emitting gas. More than 99\\% of the mass is in the lowest excitation (T$_{ex}$ $\\sim$125 K) ``warm'' component. In the inner galaxy, the warm H$_2$ emitting gas is $\\sim$15\\% of the CO(1-0)-traced cool ...

  16. Dual layer hollow fiber sorbents for trace H2S removal from gas streams

    KAUST Repository

    Bhandari, Dhaval A.

    2013-05-01

    Hollow fiber sorbents are pseudo monolithic materials with potential use in various adsorption based applications. Dual layer hollow fiber sorbents have the potential to allow thermal regeneration without direct contact of the regeneration fluid with the sorbent particles. This paper considers the application of dual layer hollow fiber sorbents for a case involving trace amounts of H2S removal from a simulated gas stream and offers a comparison with single layer hollow fiber sorbents. The effect of spin dope composition and core layer zeolite loading on the gas flux, H2S transient sorption capacity and pore structure are also studied. This work can be used as a guide to develop and optimize dual layer hollow fiber sorbent properties beyond the specific example considered here. © 2013 Elsevier Ltd.

  17. Key insights into the reacting kinetics of atmospheric pressure plasmas using He +N2 /O2 /CO2 /H2 O/Air mixtures

    Science.gov (United States)

    Murakami, Tomoyuki

    2015-09-01

    A zero dimensional kinetic chemistry computational modeling to identify the important collisional mechanisms and the dominant species in atmospheric pressure plasmas has been developed. This modeling provides an enhanced capability to tailor wide variety of reactive intermediates/species in atmospheric pressure plasmas using He +N2 /O2 /CO2 /H2 O/Air mixtures. The influence of the gas constituent, the gas temperature and the excitation frequency (kHz-, RF-, Pulsed-working) on the complex reacting chemical kinetics is clarified. This work also focuses on the benchmarking between the predictive outputs of this computer-based simulations and the diverse experimental diagnostics with particular emphasis on reactive oxygen/nitrogen intermediates/species. This work was partly supported by KAKENHI Grant Number 24561054.

  18. The RealGas and RealGasH2O Options of the TOUGH+ Code for the Simulation of Coupled Fluid and Heat Flow in Tight/Shale Gas Systems

    Energy Technology Data Exchange (ETDEWEB)

    Moridis, George; Freeman, Craig

    2013-09-30

    We developed two new EOS additions to the TOUGH+ family of codes, the RealGasH2O and RealGas . The RealGasH2O EOS option describes the non-isothermal two-phase flow of water and a real gas mixture in gas reservoirs, with a particular focus in ultra-tight (such as tight-sand and shale gas) reservoirs. The gas mixture is treated as either a single-pseudo-component having a fixed composition, or as a multicomponent system composed of up to 9 individual real gases. The RealGas option has the same general capabilities, but does not include water, thus describing a single-phase, dry-gas system. In addition to the standard capabilities of all members of the TOUGH+ family of codes (fully-implicit, compositional simulators using both structured and unstructured grids), the capabilities of the two codes include: coupled flow and thermal effects in porous and/or fractured media, real gas behavior, inertial (Klinkenberg) effects, full micro-flow treatment, Darcy and non-Darcy flow through the matrix and fractures of fractured media, single- and multi-component gas sorption onto the grains of the porous media following several isotherm options, discrete and fracture representation, complex matrix-fracture relationships, and porosity-permeability dependence on pressure changes. The two options allow the study of flow and transport of fluids and heat over a wide range of time frames and spatial scales not only in gas reservoirs, but also in problems of geologic storage of greenhouse gas mixtures, and of geothermal reservoirs with multi-component condensable (H2O and CH4) and non-condensable gas mixtures. The codes are verified against available analytical and semi-analytical solutions. Their capabilities are demonstrated in a series of problems of increasing complexity, ranging from isothermal flow in simpler 1D and 2D conventional gas reservoirs, to non-isothermal gas flow in 3D fractured shale gas reservoirs involving 4 types of fractures, micro-flow, non-Darcy flow and gas

  19. Tail gas treatment of SEWGS technology. Literature review on CO2 and H2S separation

    Energy Technology Data Exchange (ETDEWEB)

    Fabbri, E.N.; Van Dijk, H.A.J. [ECN Biomass and Energy Efficiency, Petten (Netherlands)

    2011-12-15

    This literature review is the result of an investigation of the most important way to remove sulphur for the last decades. We will discuss Claus and Claus tail gas process options to solve the problem. Next to solutions which come from membranes, direct oxidation catalysis, from acid gas removal technology, sorbent technology, and liquid oxidation. Each field will be described and explained to understand in which way it could be suitable to separate CO2 and H2S and reach our goals with regard to CO2 transport and storage conditions. Finally, the target of this work will be to propose some interesting and promising solutions in view of future experiments.

  20. Ceria supported nickel catalysts for CO removal from H2-rich gas

    Institute of Scientific and Technical Information of China (English)

    高志明; 代倩子; 马宏伟; 李展平

    2016-01-01

    CO in H2-rich gas must be removed to meet various requirements in industrial applications. Four methods, i.e., the precipi-tation method using aqueous ammonia, the complexing method using urea, the complexing method using citric acid and the precipita-tion method using ammonium carbonate, were adopted to prepare samples NiO/CeO2 as catalyst precursors for removal of CO from H2-rich gas via selective methanation reaction. The sample NiO/CeO2 prepared by the precipitation method using aqueous ammonia as precipitant exhibited the highest catalytic activity both for CO methanation and for CO2 methanation after reduction prior to the catalytic reaction. Chlorine ion was then doped to suppress CO2 conversion. Effect of chlorine doping was investigated. Over the op-timal catalyst 40%Ni(Cl0.2)/CeO2, CO in the H2-rich gas was removed to below 10 ppm with selectivity of 60% or higher at reaction temperatures 230–250 ºC in the test period of 75 h.

  1. Highly sensitive hydrogen sulfide (H2 S) gas sensors from viral-templated nanocrystalline gold nanowires

    Science.gov (United States)

    Moon, Chung Hee; Zhang, Miluo; Myung, Nosang V.; Haberer, Elaine D.

    2014-04-01

    A facile, site-specific viral-templated assembly method was used to fabricate sensitive hydrogen sulfide (H2S) gas sensors at room temperature. A gold-binding M13 bacteriophage served to organize gold nanoparticles into linear arrays which were used as seeds for subsequent nanowire formation through electroless deposition. Nanowire widths and densities within the sensors were modified by electroless deposition time and phage concentration, respectively, to tune device resistance. Chemiresistive H2S gas sensors with superior room temperature sensing performance were produced with sensitivity of 654%/ppmv, theoretical lowest detection limit of 2 ppbv, and 70% recovery within 9 min for 0.025 ppmv. The role of the viral template and associated gold-binding peptide was elucidated by removing organics using a short O2 plasma treatment followed by an ethanol dip. The template and gold-binding peptide were crucial to electrical and sensor performance. Without surface organics, the resistance fell by several orders of magnitude, the sensitivity dropped by more than a factor of 100 to 6%/ppmv, the lower limit of detection increased, and no recovery was detected with dry air flow. Viral templates provide a novel, alternative fabrication route for highly sensitive, nanostructured H2S gas sensors.

  2. IGNITION IMPROVEMENT OF LEAN NATURAL GAS MIXTURES

    Energy Technology Data Exchange (ETDEWEB)

    Jason M. Keith

    2005-02-01

    This report describes work performed during a thirty month project which involves the production of dimethyl ether (DME) on-site for use as an ignition-improving additive in a compression-ignition natural gas engine. A single cylinder spark ignition engine was converted to compression ignition operation. The engine was then fully instrumented with a cylinder pressure transducer, crank shaft position sensor, airflow meter, natural gas mass flow sensor, and an exhaust temperature sensor. Finally, the engine was interfaced with a control system for pilot injection of DME. The engine testing is currently in progress. In addition, a one-pass process to form DME from natural gas was simulated with chemical processing software. Natural gas is reformed to synthesis gas (a mixture of hydrogen and carbon monoxide), converted into methanol, and finally to DME in three steps. Of additional benefit to the internal combustion engine, the offgas from the pilot process can be mixed with the main natural gas charge and is expected to improve engine performance. Furthermore, a one-pass pilot facility was constructed to produce 3.7 liters/hour (0.98 gallons/hour) DME from methanol in order to characterize the effluent DME solution and determine suitability for engine use. Successful production of DME led to an economic estimate of completing a full natural gas-to-DME pilot process. Additional experimental work in constructing a synthesis gas to methanol reactor is in progress. The overall recommendation from this work is that natural gas to DME is not a suitable pathway to improved natural gas engine performance. The major reasons are difficulties in handling DME for pilot injection and the large capital costs associated with DME production from natural gas.

  3. Use of Drinking Water Sludge as Adsorbent for H2S Gas Removal from Biogas

    Directory of Open Access Journals (Sweden)

    Sucheela Polruang

    2017-01-01

    Full Text Available This paper reports the results of a research project, which attempts to produce a low-cost adsorbent material from waste (drinking water sludge. The main objective of this work is to study the characteristics of drinking water sludge for its adsorptive properties including morphology, surface area, porosity and chemical composition. The effect of activation conditions on H2S gas adsorption efficiency of drinking water sludge was experimented. In this study, raw drinking water sludge was divided into 3 groups. In the first group, drinking water sludge was only oven dried at 105°C. For the other 2 groups, drinking water sludge was soaked in 2.5 M NaOH solution. After soaking, the sludge was divided into 2 groups (group 2 and 3. The second group was washed with distilled water until pH 7; while the third group was not. Biogas from a swine farm was used with an initial H2S gas concentration in the range of 2,000 - 4,000 ppm. The material analysis showed that more surface area and total volume of sludge can be obtained after activated with NaOH. From the adsorption experiments, it was found that the highest adsorption capacity (qe of 87.94 mg H2S/g adsorptive material can be achieved by using sludge from the third group. Moreover, by adding of 20 wt% iron filing into sludge of the third group the adsorption capacity increased to 105.22 mg H2S/g adsorptive material. Drinking water sludge can be considered as a high potential energy saving and low cost adsorbent for removal of H2S.

  4. The controlling factors and distribution prediction of H2S formation in marine carbonate gas reservoir, China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Generally, there are some anhydrites in carbonate reservoir, as H2S is also familiar in carbonate oil and gas reservoirs. Nowadays, natural gas with high H2S concentration is usually considered as TSR origin,so there is close relationship between H2S and anhydrite. On the contrary, some carbonate rocks with anhydrite do not contain H2S. Recently, researches show that H2S isonly a necessary condition of H2S formation. The reservoir porosity, sulfate ion content within formation water, reservoir temperature,oil/gas and water interface, hydrocarbon and some elements of reservoir rock have great controlling effects on the TSR occurrence. TSR deoxidizes hydrocarbon into the acidic gas such as H2S and CO2,and the H2S formation is controlled by TSR occurrence, so the relationship among reaction room, the contact chance of sulfate ion and hydrocarbon, the reservoir temperature has great influence on the TSR reaction. H2S has relatively active chemical quality, so it is still controlled by the content of heavy metal ion. Good conditions of TSR reaction and H2S preservation are the prerequisite of H2S distribution prediction. This paper builds a predictive model based on the characteristic of natural gas reservoir with high H2S-bearing. In the porosity reservoir with anhydrite, the formation water is rich in sulfate and poor in heavy metal ion. Oil and gas fill and accumulate in the gas reservoir with good preservation conditions, and they suffered high temperature later, which indicates the profitable area of natural gas with high H2S-bearing.

  5. The role of 3-body H$_2$ formation in the fragmentation of primordial gas

    CERN Document Server

    Dutta, Jayanta; Clark, Paul C; Klessen, Ralf S

    2015-01-01

    It has been shown that the behaviour of primordial gas collapsing in a dark matter minihalo can depend on the adopted choice of 3-body H$_2$ formation rate. The uncertainties in this rate span two orders of magnitude in the current literature, and so it remains a source of uncertainty in our knowledge of population III star formation. Here we investigate how the amount of fragmentation in primordial gas depends on the adopted 3-body rate. We present the results of calculations that follow the chemical and thermal evolution of primordial gas as it collapses in two dark matter minihalos. Our results on the effect of 3-body rate on the evolution until the first protostar forms agree well with previous studies. However, our modified version of GADGET-2 SPH also includes sink particles, which allows us to follow the initial evolution of the accretion disc that builds up on the centre of each halo, and capture the fragmentation in gas as well as its dependence on the adopted 3-body H$_2$ formation rate. We find tha...

  6. Efficiency Improved by H2 Forming Gas Treatment for Si-Based Solar Cell Applications

    Directory of Open Access Journals (Sweden)

    Yuang-Tung Cheng

    2010-01-01

    Full Text Available The photovoltaic (PV effects have been investigated and improved using efficient treatments both on single-crystalline (sc and on multicrystalline (mc silicon (Si solar cells. The major effect of forming gas (FG treatment on solar cell performance is the fill-factor values, which increase 3.75% and 8.28%, respectively, on sc-Si and mc-Si solar cells. As for the optimal 15%-H2 ratio and 40-minute FG treatment, the conversion efficiency (η values drastically increase to 14.89% and 14.31%, respectively, for sc- and mc-Si solar cells. Moreover, we can measure the internal quantum efficiency (IQE values increase with H2-FG treatment under visible wavelength (400~900 nm radiation. Thus based on the work in this research, we confirm that H2 passivation has become crucial both in PV as well as in microelectronics fields. Moreover, the developed mc-Si solar cell by proper H2 FG treatment is quite suitable for commercial applications.

  7. Influence of argon fraction on plasma parameters in H2-N2 mixture discharge with cathodic cage

    Science.gov (United States)

    Naeem, Muhammad; Zaka-ul-Islam, Mujahid; Khattak, Zahid Iqbal; Shafiq, Muhammad; Zakaullah, Muhammad

    2017-01-01

    Low-pressure H2-N2 mixture pulsed DC plasmas with a cathodic cage (active screen) are widely used for plasma nitriding applications. In this study, the low-pressure H2-N2 mixture plasma with a cathodic cage generated by 50 Hz pulsed DC source is investigated with triple Langmuir probe and optical emission spectroscopy. The electron temperature (TeLP T e LP ) and electron number density (ne) are measured using a triple Langmuir probe (TLP). The excitation temperature (TexcOES T e xc OES ) is calculated spectroscopically using Boltzmann plot method whereas nitrogen dissociation fraction is estimated using actinometry as well as the intensity ratio method (IN (746.83 nm)/IN2(337.1 nm)). The results show that the electron and excitation temperatures, electron density and nitrogen atomic species density [N] all increase with the argon admixture, however, the important molecular ionized species density [N2+ N 2 + ] significantly decreases beyond 30% addition. This study provides useful information about the influence of the argon addition on plasma parameters and active species generation. As a result it helps to optimize the plasma nitriding system as a function of argon admixture to avoid random trials in the processing.

  8. CO2 and H2S gas injection heavy oil field

    Energy Technology Data Exchange (ETDEWEB)

    Padua, K.G.O. [Petrobras (Canada)

    2011-07-01

    Heavy oils constitute one of the largest fossil fuel reserves on earth; among them there are naturally fractured carbonate reservoirs under bottomwater. Those reservoirs are composed of sour heavy oil and its recovery is difficult, miscible processes are expensive and thermal methods are inefficient due to the harsh conditions. The aim of this paper is to investigate the use of injection of carbon dioxide and hydrogen sulfide mixtures. Fluid and reservoir characterizations were conducted using published observations, dynamic modeling and a comparative study. Reservoir performance under natural depletion and immiscible gas injection with effluent gas were then analyzed and compared. Expected breakthrough and composition of the produced fluid were presented in this study to provide the input necessary for operational planning. This paper presented a comparison between reservoir performance under natural depletion and immiscible gas injection, providing qualitative information to evaluate an effluent gas project.

  9. Computation on pipe dynamic response induced by deflagration of H2 and air mixture

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Computation is devoted to evaluating structural safety of a heat exchanger inside a reactor whose geometry can be simplified as outer and inner pipes as well as a chamber. This paper has numerically studied deflagration of hydrogen air mixture and pipe dynamic responses. The Navier-Stokes equations coupled with multi-species mass equation are solved by TVD scheme to get flow-field solution based on MPI and multi-block methods. Combustion is described by a 11-species and 23-step reaction model. The source term is treated implicitly to involve species production and depletion. Ignition is approximated by input energy CpT per unit mass in a specified period and zone. Finally,contours of pressure and OH mass fraction at different time pe-riods and pressure histories at fixed points are obtained. When loading is specified as wall pressure,virtual work theorem in Lagrangian frame which describes pipe response is solved by FEM to obtain stress and strain distributions. Results show that shock waves can be generated and reflected on the walls of the chamber and pipes. The shock waves and flame can not be dis-sipated in a narrow gap spanning 2 mm. Meanwhile,stress waves are generated. They propagate outwards on the inner and outer pipe walls. At the gap exit,shock wave diffracts and impacts on the inner pipe walls. Coupled with hot jet from the gap,reignition occurs on the inner pipe wall surfaces. Then,flame catches up the leading shock and shock front deforms into a planar one although the shock front passes through a short divergent section downstream. Also,stress concentrates along the intersected lines among the top,bottom and side walls. This means that the chamber is an easily damaged component. The methods provided in this paper can be used to evaluate structural safety.

  10. Highly Excited H2 in Herbig-Haro 7: Formation Pumping in Shocked Molecular Gas?

    CERN Document Server

    Pike, R E; Burton, M G; Chrysostomou, A

    2016-01-01

    We have obtained K-band spectra at R~5,000 and angular resolution 0.3" of a section of the Herbig-Haro 7 (HH7) bow shock, using the Near-Infrared Integral Field Spectrograph at Gemini North. Present in the portion of the data cube corresponding to the brightest part of the bow shock are emission lines of H2 with upper state energies ranging from ~6,000 K up to the dissociation energy of H2, ~50,000 K. Because of low signal-to-noise ratios, the highest excitation lines cannot be easily seen elsewhere in the observed region. However, excitation temperatures, measured throughout much of the observed region using lines from levels as high as 25,000 K, are a strong function of upper level energy, indicating that the very highest levels are populated throughout. The level populations in the brightest region are well fit by a two-temperature model, with 98.5% of the emitting gas at T=1800 K and 1.5% at T=5200 K. The bulk of the H2 line emission in HH7, from the 1,800 K gas, has previously been well modeled by a cont...

  11. Definitive ideal-gas thermochemical functions of the H$_2$$^{16}$O molecule

    CERN Document Server

    Furtenbacher, Tibor; Hruby, Jan; Kyuberis, Aleksandra A; Zobov, Nikolai F; Polyansky, Oleg L; Tennyson, Jonathan; Császár, Attila G

    2016-01-01

    $Q_{\\rm int}$($T$), of the H$_2$$^{16}$O molecule is reported for temperatures between 0 and 6000 K. Determination of $Q_{\\rm int}$($T$) is principally based on the direct summation technique involving all accurate experimental energy levels known for H$_2$$^{16}$O (almost 20~000 rovibrational energies including an almost complete list up to a relative energy of 7500 \\cm), augmented with a less accurate but complete list of first-principles computed rovibrational energy levels up to the first dissociation limit, about 41~000 \\cm\\ (the latter list includes close to one million bound rovibrational energy levels up to $J = 69$, where $J$ is the rotational quantum number). Partition functions are developed for {\\it ortho}- and {\\it para}-H$_2$$^{16}$O as well as for their equilibrium mixture. Unbound rovibrational states above the first dissociation limit are considered using an approximate model treatment. The effect of the excited electronic states on the thermochemical functions is neglected, as their contribu...

  12. Hydrogen sulfide (H2S) and sour gas effects on the eye. A historical perspective.

    Science.gov (United States)

    Lambert, Timothy William; Goodwin, Verona Marie; Stefani, Dennis; Strosher, Lisa

    2006-08-15

    The toxicology of hydrogen sulfide (H(2)S) and sour gas on the eye has a long history beginning at least with Ramazzini's observations [Ramazzini B. Diseases of Workers--De Morbis Artificum Diatriba--1713. Wright WC (trans). New York, C. Hafner Publishing Co Inc.; 1964. 98-99 pp.]. In contrast, a recent review by Alberta Health and Wellness (AHW Report) concluded that there is little evidence of eye irritation following short-term exposures to H(2)S at concentrations up to 100ppm and that the H(2)S literature on the eye is a series of unsubstantiated claims reproduced in review articles dating back to the 1930s [Alberta Health and Wellness (AHW report). Health effects associated with short-term exposure to low levels of hydrogen sulfide: a technical review, Alberta Health and Wellness, October 2002, 81pp.]. In this paper, we evaluated this claim through a historical review of the toxicology of the eye. Ramazzini noted the effects of sewer gas on the eye [Ramazzini B. Diseases of Workers--De Morbis Artificum Diatriba--1713. Wright WC (trans). New York, C. Hafner Publishing Co Inc. 1964. 98-99 pp.]. Lehmann experimentally showed eye effects in men at 70-90ppm H(2)S and also in animals [Lehmann K. Experimentalle Studien uber den Einfluss technisch und hygienisch wichtiger Gase und Dampfe auf den Organismus. Arch Hyg 1892;14:135-189]. In 1923, Sayers, Mitchell and Yant reported eye effects in animals and men at 50ppm H(2)S. Barthelemy showed eye effects in animals and men at 20ppm H(2)S [Barthelemy HL. Ten years' experience with industrial hygiene in connection with the manufacture of viscose rayon. J Ind Hyg Toxicol 1939;21:141-51]. Masure experimentally showed that H(2)S is the causative agent of eye impacts in animals and men [Masure R. La Keratoconjunctivite des filatures de viscose; etude clinique and experiementale. Rev Belge Pathol 1950;20:297-341]. Michal upon microscopic examination of the rat's cornea, found nuclear pyknosis, edema and separation of cells in

  13. Comparison of diamond growth with different gas mixtures in microwave plasma asssited chemical vapor deposition (MWCVD

    Directory of Open Access Journals (Sweden)

    Corat Evaldo J.

    2003-01-01

    Full Text Available In this work we study the influence of oxygen addition to several halocarbon-hydrogen gas systems. Diamond growth have been performed in a high power density MWCVD reactor built in our laboratory. The growth experiments are monitored by argon actinometry as a reference to plasma temperature and atomic hydrogen production, and by mass spectrometry to compare the exhaust gas composition. Atomic hydrogen actinometry revealed that the halogen presence in the gas phase is responsible for a considerable increase of atomic hydrogen concentration in the gas phase. Mass spectrometry shows similar results for all gas mixtures tested. Growth studies with oxygen addition to CF4/H2, CCl4/H2, CCl2F2/H2 and CH3Cl/H2 reveals that oxygen increases the carbon solubility in the gas phase but no better diamond growth conditions were found. Halogens are not, per se, eligible for diamond growth. All the possible advantages, as the higher production of atomic hydrogen, have been suppressed by the low carbon solubility in the gas phase, even when oxygen is added. The diamond growth with small amount of CF4 added to CH4/H2 mixture is not aggressive to the apparatus but brings several advantages to the process.

  14. GAS PHASE STRUCTURE AND STABILITY OF COMPLEX FORMED BY H2O, NH3, H2S AND THEIR METHYL DERIVATIVES WITH THE CATION CO2+

    Directory of Open Access Journals (Sweden)

    Cahyorini Kusumawardani

    2010-06-01

    Full Text Available Ab initio molecular orbital calculations at the Hartree-Fock-Self Consistent Field (HF-SCF have been performed in order to determine the structure and gas phase energies of complex formed by the Lewis bases of H2O, NH3, H2S and their methyl derivatives with the cation Co2+. The relative basicities of the base studied depend on both the substituent. The gas-phase interaction energies computed by the SCF method including electron correlation Møller-Plesset 2 (MP2 dan Configuration Iteration (CI were comparable in accuracy. The binding energies computed by these two methods reach the targeted chemical accuracy.   Keywords: ab initio calculation, cobalt complex, structure stability

  15. Electrochemical oxidation of carbon monoxide: from platinum single crystals to low temperature fuel catalysts. Part II: Electrooxidation of H2, CO and H2/CO mixtures on well characterized PtMo alloy

    Directory of Open Access Journals (Sweden)

    PHILIP N. ROSS JR.

    2003-03-01

    Full Text Available The oxidation of hydrogen and hydrogen–carbon monoxide mixture has been investigated on well-characterized metallurgically prepared platinum–molybdenum (PtMo alloys. It was concluded that the optimum surface concentration of molybdenum is near 23 mol.%. Based on experimentally determined parameters and simulations, the mechanism of the oxidation of CO/H2 mixtures is discussed.

  16. The Nature of the H2-Emitting Gas in the Crab Nebula

    CERN Document Server

    Richardson, C T; Ferland, G J; Loh, E D; Kuehn, C A; Fabian, A C; Salomé, Philippe

    2012-01-01

    Understanding how molecules and dust might have formed within a rapidly expanding young supernova remnant is important because of the obvious application to vigorous supernova activity at very high redshift. In previous papers, we found that the H2 emission is often quite strong, correlates with optical low-ionization emission lines, and has a surprisingly high excitation temperature. Here we study Knot 51, a representative, bright example, for which we have available long slit optical and NIR spectra covering emission lines from ionized, neutral, and molecular gas, as well as HST visible and SOAR Telescope NIR narrow-band images. We present a series of CLOUDY simulations to probe the excitation mechanisms, formation processes and dust content in environments that can produce the observed H2 emission. We do not try for an exact match between model and observations given Knot 51's ambiguous geometry. Rather, we aim to explain how the bright H2 emission lines can be formed from within the volume of Knot 51 that...

  17. Formation of S-bearing Species by VUV/EUV Irradiation of H2S-containing Ice Mixtures: Photon Energy and Carbon Source Effects

    Science.gov (United States)

    Chen, Y.-J.; Juang, K.-J.; Nuevo, M.; Jiménez-Escobar, A.; Muñoz Caro, G. M.; Qiu, J.-M.; Chu, C.-C.; Yih, T.-S.; Wu, C.-Y. R.; Fung, H.-S.; Ip, W.-H.

    2015-01-01

    Carbonyl sulfide (OCS) is a key molecule in astrobiology that acts as a catalyst in peptide synthesis by coupling amino acids. Experimental studies suggest that hydrogen sulfide (H2S), a precursor of OCS, could be present in astrophysical environments. In the present study, we used a microwave-discharge hydrogen-flow lamp, simulating the interstellar UV field, and a monochromatic synchrotron light beam to irradiate CO:H2S and CO2:H2S ice mixtures at 14 K with vacuum ultraviolet (VUV) or extreme ultraviolet (EUV) photons in order to study the effect of the photon energy and carbon source on the formation mechanisms and production yields of S-containing products (CS2, OCS, SO2, etc.). Results show that (1) the photo-induced OCS production efficiency in CO:H2S ice mixtures is higher than that of CO2:H2S ice mixtures; (2) a lower concentration of H2S enhances the production efficiency of OCS in both ice mixtures; and (3) the formation pathways of CS2 differ significantly upon VUV and EUV irradiations. Furthermore, CS2 was produced only after VUV photoprocessing of CO:H2S ices, while the VUV-induced production of SO2 occurred only in CO2:H2S ice mixtures. More generally, the production yields of OCS, H2S2, and CS2 were studied as a function of the irradiation photon energy. Heavy S-bearing compounds were also observed using mass spectrometry during the warm-up of VUV/EUV-irradiated CO:H2S ice mixtures. The presence of S-polymers in dust grains may account for the missing sulfur in dense clouds and circumstellar environments.

  18. Assessment of existing H2/O2 chemical reaction mechanisms at reheat gas turbine conditions

    CERN Document Server

    Weydahl, Torleif; Seljeskog, Morten; Haugen, Nils Erland L

    2011-01-01

    This paper provides detailed comparisons of chemical reaction mechanisms of H2 applicable at high preheat temperatures and pressures relevant to gas turbine and particularly Alstom's reheat gas turbine conditions. It is shown that the available reaction mechanisms exhibit large differences in several important elementary reaction coefficients. The reaction mechanisms are assessed by comparing ignition delay and laminar flame speed results obtained from CHEMKIN with available data, however, the amount of data at these conditions is scarce and a recommended candidate among the mechanisms can presently not be selected. Generally, the results with the GRI-Mech and Leeds mechanisms deviate from the Davis, Li, O'Conaire, Konnov and San Diego mechanisms, but there are also significant deviations between the latter five mechanisms that altogether are better adapted to hydrogen. The differences in ignition delay times between the dedicated hydrogen mechanisms (O'Conaire, Li and Konnov) range from approximately a maxim...

  19. Mathematical modelling and simulation on the adsorption of Hydrogen Sulfide (H2S) gas

    Science.gov (United States)

    Zulkefli, N. N.; Masdar, M. S.; Isahak, W. R. W.; Jahim, J.; Majlan, E. H.; Rejab, S. A. M.; Lye, C. C.

    2017-06-01

    Hydrogen sulfide, H2S, a pollutant in biofuel gas, i.e., biohydrogen and biomethane, is produced at concentrations ranging from 100 ppm to 10,000 ppm and is recommended to be removed at the early stage of gas purification because it is known as a problematic compound. In this study, adsorption technologies show a promising technique to remove H2S from biofuel gas, which mainly depends on the operating parameters and adsorbent ability. In this study, the development of the models is important to investigate the fundamentals of H2S adsorption mechanism. The fitted mathematics model was performed by considering several assumptions made for fixed-bed adsorption, leading to the determination of the breakthrough curve by solving a set of partial differential equations (PDEs). The operating parameters were as follows: varied inlet concentration at 1000 ppm to 10,000 ppm, flow rate at 0.2 L/min to 0.6 L/min, length bed used at 10 cm to 30 cm, and pressure at 1.5 atm to 5 atm. The adsorption performance was also studied by using commercial activated carbon such as palm kernel shell (PKS-AC), coconut shell activated carbon (coconut shell-AC), and zeolite ZSM-5. To support the effectiveness of the mathematical models, the adsorption test was performed by loading the adsorbent into the fixed-bed adsorption column at an overall diameter of 6 cm and height of 30 cm. The system operated under room temperature, H2S inlet concentration of 1000 ppm, and varying flow rate as in the modelling for PKS-AC. As a result, in the modelling study, the inlet concentration effect was highest in adsorption capacity, breakthrough time, and exhaustion time. However, the increase of flow rate and length bed used only affected the breakthrough and exhaustion times but not adsorption capacity. The total pressure used did not affect adsorption performance. Coconut shell-AC shows longer exhaustion time compared with other adsorbents due to the less frequent changes of adsorbent. In the experimental

  20. KINETICS OF DIRECT OXIDATION OF H2S IN COAL GAS TO ELEMENTAL SULFUR

    Energy Technology Data Exchange (ETDEWEB)

    K.C. Kwon

    2004-01-01

    The direct oxidation of H{sub 2}S to elemental sulfur in the presence of SO{sub 2} is ideally suited for coal gas from commercial gasifiers with a quench system to remove essentially all the trace contaminants except H{sub 2}S. This direct oxidation process has the potential to produce a super clean coal gas more economically than both conventional amine-based processes and the hot-gas desulfurization using regenerable metal oxide sorbents followed by Direct Sulfur Recovery Process. The objective of this research is to support the near- and long-term process development efforts to commercialize this direct oxidation technology. The objectives of this research are to measure kinetics of direct oxidation of H{sub 2}S to elemental sulfur in the presence of a simulated coal gas mixture containing SO{sub 2}, H{sub 2}, and moisture, using 160-{micro}m C-500-04 alumina catalyst particles and a micro bubble reactor, and to develop kinetic rate equations and model the direct oxidation process to assist in the design of large-scale plants. This heterogeneous catalytic reaction has gaseous reactants such as H{sub 2}S and SO{sub 2}. However, this heterogeneous catalytic reaction has heterogeneous products such as liquid elemental sulfur and steam. To achieve the above-mentioned objectives, experiments on conversion of hydrogen sulfide into liquid elemental sulfur were carried out for the space time range of 1-6 milliseconds at 125-155 C to evaluate effects of reaction temperature, moisture concentration, reaction pressure on conversion of hydrogen sulfide into liquid elemental sulfur. Simulated coal gas mixtures consist of 70 v% hydrogen, 2,500-7,500-ppmv hydrogen sulfide, 1,250-3,750 ppmv sulfur dioxide, and 0-15 vol% moisture, and nitrogen as remainder. Volumetric feed rates of a simulated coal gas mixture to a micro bubble reactor are 100 cm{sup 3}/min at room temperature and atmospheric pressure. The temperature of the reactor is controlled in an oven at 125-155 C. The

  1. KINETICS OF DIRECT OXIDATION OF H2S IN COAL GAS TO ELEMENTAL SULFUR

    Energy Technology Data Exchange (ETDEWEB)

    K.C. Kwon

    2005-01-01

    The direct oxidation of H{sub 2}S to elemental sulfur in the presence of SO{sub 2} is ideally suited for coal gas from commercial gasifiers with a quench system to remove essentially all the trace contaminants except H{sub 2}S. This direct oxidation process has the potential to produce a super clean coal gas more economically than both conventional amine-based processes and the hot-gas desulfurization using regenerable metal oxide sorbents followed by Direct Sulfur Recovery Process. The objective of this research is to support the near- and long-term process development efforts to commercialize this direct oxidation technology. The objectives of this research are to measure kinetics of direct oxidation of H{sub 2}S to elemental sulfur in the presence of a simulated coal gas mixture containing SO{sub 2}, H{sub 2}, and moisture, using 160-{micro}m C-500-04 alumina catalyst particles and a micro bubble reactor, and to develop kinetic rate equations and model the direct oxidation process to assist in the design of large-scale plants. This heterogeneous catalytic reaction has gaseous reactants such as H{sub 2}S and SO{sub 2}. However, this heterogeneous catalytic reaction has heterogeneous products such as liquid elemental sulfur and steam. To achieve the above-mentioned objectives, experiments on conversion of hydrogen sulfide into liquid elemental sulfur were carried out for the space time range of 0.059-0.87 seconds at 125-155 C to evaluate effects of reaction temperature, H{sub 2}S concentration, reaction pressure, and catalyst loading on conversion of hydrogen sulfide into liquid elemental sulfur. Simulated coal gas mixtures consist of 62-78 v% hydrogen, 3,000-7,000-ppmv hydrogen sulfide, 1,500-3,500 ppmv sulfur dioxide, and 10 vol % moisture, and nitrogen as remainder. Volumetric feed rates of a simulated coal gas mixture to a micro bubble reactor are 50 cm{sup 3}/min at room temperature and atmospheric pressure. The temperature of the reactor is controlled in an

  2. New Gas Carburizing Method for Minimizing CO2 Emission by Saving Resources and Selective Removal of H2 in Furnace

    Science.gov (United States)

    Mizukoshi, Tomoyuki; Yokoyama, Yujiro; Hoshino, Hideaki; Ishigami, Itsuo; Usui, Tateo

    An attempt has been made to develop a new gas carburizing furnace with the system that discharges H2 gas selectively from the atmosphere in the furnace. Polyimide hollow-fiber membrane filter on the market was selected as a filter that was expected to have good H2 gas permeability and selectivity. The results of the various gas permeability measurements of this filter showed that it had superior H2 gas permeability and selectivity. Using this gas filter module, a new industrial gas carburizing furnace that had ‘H2 gas selective discharging system’ was produced as a trial. Use of this furnace made possible to stabilize the gas carburizing atmosphere in the furnace under the lower carrier gas flow rate condition (below 25% of standard condition). It was confirmed that the carbon concentration profile of the steel carburized with the new carburizing furnace under lower carrier gas flow rate condition was comparable to that of the specimen carburized under standard carrier gas flow rate condition.

  3. State-to-state vibrational kinetics of H$_2$ and H$_2^+$ in a post-shock cooling gas with primordial composition

    CERN Document Server

    Coppola, C M; Bruno, D; Esposito, F; Galli, D; Palla, F; Longo, S

    2016-01-01

    The radiative cooling of shocked gas with primordial chemical composition is an important process relevant to the formation of the first stars and structures, as well as taking place also in high velocity cloud collisions and supernovae explosions. Among the different processes that need to be considered, the formation kinetics and cooling of molecular hydrogen are of prime interest, since they provide the only way to lower the gas temperature to values well below $\\sim$10$^4$~K. In previous works, the internal energy level structure of H$_2$ and its cation has been treated in the approximation of rovibrational ground state at low densities, or trying to describe the dynamics using some arbitrary $v>0$ H$_2$ level that is considered representative of the excited vibrational manifold. In this study, we compute the vibrationally resolved kinetics for the time-dependent chemical and thermal evolution of the post-shock gas in a medium of primordial composition. The calculated non-equilibrium distributions are use...

  4. Absolute Infrared Cross Sections of Gas-Phase H2O2 Using Fourier Transform Mid-Infrared Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Timothy J.; Blake, Thomas A.; Sams, Robert L.; Burton, Sarah D.

    2010-01-29

    We report quantitative spectra of pressure-broadened H2O2 vapor. An 83% solution was flowed into a disseminator and diluted with N2 gas; water lines were subtracted. The H2O2 spectrum spans the IR and compares well with HITRAN values for ν6 band.

  5. An experimental approach aiming the production of a gas mixture composed of hydrogen and methane from biomass as natural gas substitute in industrial applications.

    Science.gov (United States)

    Kraussler, Michael; Schindler, Philipp; Hofbauer, Hermann

    2017-03-11

    This work presents an experimental approach aiming the production of a gas mixture composed of H2 and CH4, which should serve as natural gas substitute in industrial applications. Therefore, a lab-scale process chain employing a water gas shift unit, scrubbing units, and a pressure swing adsorption unit was operated with tar-rich product gas extracted from a commercial dual fluidized bed biomass steam gasification plant. A gas mixture with a volumetric fraction of about 80% H2 and 19% CH4 and with minor fractions of CO and CO2 was produced by employing carbon molecular sieve as adsorbent. Moreover, the produced gas mixture had a lower heating value of about 15.5MJ·m(-3) and a lower Wobbe index of about 43.4MJ·m(-3), which is similar to the typical Wobbe index of natural gas.

  6. Study of Room Temperature H2S Gas Sensing Behavior of CuO-modified BSST Thick Film Resistors

    Directory of Open Access Journals (Sweden)

    H. M. Baviskar

    2008-05-01

    Full Text Available Thick films of (Ba0.1Sr0.9(Sn0.5Ti0.5O3 referred as BSST, were prepared by screen-printing technique. The preparation, characterization and gas sensing properties of pure and CuO-BSST mixed oxide semiconductors have been investigated. The mixed oxides were obtained by dipping the pure BSST thick films into 0.01 M aqueous solution of CuCl2, for different intervals of time. Pure BSST was observed to be less sensitive to H2S gas. However, mixed oxides of CuO and BSST were observed to be highly sensitive to H2S gas. Upon exposure to H2S gas, the barrier height of CuO-BSST intergranular regions decreases markedly due to the chemical transformation of CuO into well conducting CuS leading to a drastic decrease in resistance. The crucial gas response was found to H2S gas at room temperature and no cross sensitivity was observed to other hazardous and polluting gases. The effects of microstructure and doping concentration on the gas response, selectivity, response and recovery of the sensor in the presence of H2S gas were studied and discussed.

  7. Phase Composition of Ni/Mg1−xNixO as a Catalyst Prepared for Selective Methanation of CO in H2-Rich Gas

    OpenAIRE

    Mengmeng Zhang; Hongwei Ma; Zhiming Gao

    2015-01-01

    Supported Ni catalysts Ni/Mg1−xNixO were prepared by reducing samples NiO-MgO in H2/N2 mixture gas at 500°C~800°C for selective methanation of CO in H2-rich gas (CO-SMET). The samples NiO-MgO were obtained by heating water slurry of MgO and Ni(NO3)2 in a rotary evaporator at 80°C and a final calcination in air at 400°C~800°C. X-ray diffraction (XRD) and temperature programmed reduction (TPR) measurements demonstrate that the samples NiO-MgO were composed of solid solution Mg1−yNiyO as the mai...

  8. The genesis of H2S in the Weiyuan Gas Field,Sichuan Basin and its evidence

    Institute of Scientific and Technical Information of China (English)

    ZHU GuangYou; ZHANG ShuiChang; LIANG YingBo; LI QiRong

    2007-01-01

    The Sinian Dengying Formation gas pool in Weiyuan is the oldest large-scale sulfur-bearing gas field in China,which has a H2S content ranging from 0.8% to 1.4%.The Cambrian Xixiangchi Formation gas pool discovered recently above the Dengying Formation contains gas geochemical behaviors similar to those of Dengying Formation but different in sulfur isotopes of H2S.Investigations show that though these two Sinian and Cambrian gas pools are separate ones,they share the same Cambrian source rock.The higher dry coefficient,heavier carbon isotopes,sulfur isotopes of sulfide,lower filling of gas pools,formation water characteristics,reservoir properties and H2S distribution,indicate that H2S in both the Sinian and Cambrian gas pools originates from TSR.The sulfur isotopes of sulfates have shown that H2S was formed in respective pools,namely hydrocarbons charged into the pools reacted with the Dengying Formation and the Xixiangchi Formation gypsum (TSR),respectively,to form H2S.Compared with sulfur isotopes of sulfates in each pool,δ34S values of H2S are 8‰ lighter for the Dengying Formation pool and 12‰ lighter for the Xixiangchi Formation pool,respectively,which is attributed to the difference in temperatures of TSR occurrence.The reservoir temperature of the Xixiangchi Formation pool is about 40℃ lower than that of the Dengying Formation pool.Temperature plays a controlling role in both the sulfur isotopic fractionation and amounts of H2S generation during TSR.

  9. Cu-TDPAT, an rht -type dual-functional metal-organic framework offering significant potential for use in H 2 and natural gas purification processes operating at high pressures

    KAUST Repository

    Wu, Haohan

    2012-08-09

    The separations of CO 2/CO/CH 4/H 2, CO 2/H 2, CH 4/H 2, and CO 2/CH 4 mixtures at pressures ranging to 7 MPa are important in a variety of contexts, including H 2 production, natural gas purification, and fuel-gas processing. The primary objective of this study is to demonstrate the selective adsorption potential of an rht-type metal-organic framework [Cu 3(TDPAT)(H 2O) 3]·10H 2O·5DMA (Cu-TDPAT), possessing a high density of both open metal sites and Lewis basic sites. Experimental high pressure pure component isotherm data for CO 2, CO, CH 4, and H 2 are combined with the Ideal Adsorbed Solution Theory (IAST) for estimation of mixture adsorption equilibrium. The separation performance of Cu-TDPAT is compared with four other microporous materials, specifically chosen in order to span a wide range of physicochemical characteristics: MgMOF-74, MIL-101, LTA-5A, and NaX. For all mixtures investigated, the capacity of Cu-TDPAT to produce the desired product, H 2 or CH 4, satisfying stringent purity requirements, in a fixed bed operating at pressures exceeding about 4 MPa, is either comparable to, or exceeds, that of other materials. © 2012 American Chemical Society.

  10. Effect of pressure on the lean limit flames of H2-CH4-air mixture in tubes

    KAUST Repository

    Zhou, Zhen

    2017-05-25

    The lean limit flames of H2-CH4-air mixtures stabilized inside tubes in a downward flow are experimentally and numerically investigated at elevated pressures ranging from 2 to 5 bar. For the shapes of lean limit flames, a change from ball-like flame to cap-like flame is experimentally observed with the increase of pressure. This experimentally observed phenomenon is qualitatively predicted by numerical simulations. The structure of ball-like and cap-like lean limit flames at all tested pressures is analysed in detail based on the numerical predictions. The results show that the lean limit flames are located inside a recirculation zone at all tested pressures. For the leading edges of the lean limit flames at all tested pressures, the fuel transport is controlled by both convection and diffusion. For the trailing edge of the ball-like lean limit flame at 2 bar, the fuel transport is dominated by diffusion. However, with increasing pressure, the transport contribution caused by convection in the trailing edges of the lean limit flames increases. Finally, the influence of transport and chemistry on the predicted ultra lean flames and lean flammability limit is analysed at elevated pressures.

  11. Kinetics of Direct Oxidation of H2S in Coal Gas to Elemental Sulfur

    Energy Technology Data Exchange (ETDEWEB)

    K.C. Kwon

    2005-11-01

    kinetics of direct oxidation of H{sub 2}S to elemental sulfur in the presence of a simulated coal gas mixture containing SO{sub 2}, H{sub 2}, and moisture, using 160-{micro}m C-500-04 alumina catalyst particles and 400 square cells/inch{sup 2}, {gamma}-Al{sub 2}O{sub 3}-wash-coated monolithic catalyst, and various reactors such as a micro packed-bed reactor, a micro bubble reactor, and a monolithic catalyst reactor, and to develop kinetic rate equations and model the direct oxidation process to assist in the design of large-scale plants. This heterogeneous catalytic reaction has gaseous reactants such as H{sub 2}S and SO{sub 2}. However, this heterogeneous catalytic reaction has heterogeneous products such as liquid elemental sulfur and steam.

  12. KINETICS OF DIRECT OXIDATION OF H2S IN COAL GAS TO ELEMENTAL SULFUR

    Energy Technology Data Exchange (ETDEWEB)

    K.C. Kwon

    2003-01-01

    The direct oxidation of H{sub 2}S to elemental sulfur in the presence of SO{sub 2} is ideally suited for coal gas from commercial gasifiers with a quench system to remove essentially all the trace contaminants except H{sub 2}S. This direct oxidation process has the potential to produce a super clean coal gas more economically than both conventional amine-based processes and HGD/DSRP. The objective of this research is to support the near- and long-term DOE efforts to commercialize this direct oxidation technology. The objectives of this research are to measure kinetics of direct oxidation of H{sub 2}S to elemental sulfur in the presence of a simulated coal gas mixture containing SO{sub 2}, H{sub 2}, and moisture, using 60-{micro}m C-500-04 alumina catalyst particles and a PFA differential fixed-bed micro reactor, and to develop kinetic rate equations and model the direct oxidation process to assist in the design of large-scale plants. To achieve the above-mentioned objectives, experiments on conversion of hydrogen sulfide into elemental sulfur were carried out for the space time range of 0.01-0.047 seconds at 125-155 C to evaluate effects of reaction temperatures, moisture concentrations, reaction pressures on conversion of hydrogen sulfide into elemental sulfur. Simulated coal gas mixtures consist of 61-89 v% hydrogen, 2,300-9,200-ppmv hydrogen sulfide, 1,600-4,900 ppmv sulfur dioxide, and 2.6-13.7 vol % moisture, and nitrogen as remainder. Volumetric feed rates of a simulated coal gas mixture to the reactor are 100-110 cm{sup 3}/min at room temperature and atmospheric pressure (SCCM). The temperature of the reactor is controlled in an oven at 125-155 C. The pressure of the reactor is maintained at 28-127 psia. The following results were obtained based on experimental data generated from the differential reactor system, and their interpretations, (1) Concentration of moisture and concentrations of both H{sub 2}S and SO{sub 2} appear to affect slightly reaction

  13. Inhalation pressure distributions for medical gas mixtures calculated in an infant airway morphology model.

    Science.gov (United States)

    Gouinaud, Laure; Katz, Ira; Martin, Andrew; Hazebroucq, Jean; Texereau, Joëlle; Caillibotte, Georges

    2015-01-01

    A numerical pressure loss model previously used for adult human airways has been modified to simulate the inhalation pressure distribution in a healthy 9-month-old infant lung morphology model. Pressure distributions are calculated for air as well as helium and xenon mixtures with oxygen to investigate the effects of gas density and viscosity variations for this age group. The results indicate that there are significant pressure losses in infant extrathoracic airways due to inertial effects leading to much higher pressures to drive nominal flows in the infant airway model than for an adult airway model. For example, the pressure drop through the nasopharynx model of the infant is much greater than that for the nasopharynx model of the adult; that is, for the adult-versus-child the pressure differences are 0.08 cm H2O versus 0.4 cm H2O, 0.16 cm H2O versus 1.9 cm H2O and 0.4 cm H2O versus 7.7 cm H2O, breathing helium-oxygen (78/22%), nitrogen-oxygen (78/22%) and xenon-oxygen (60/40%), respectively. Within the healthy lung, viscous losses are of the same order for the three gas mixtures, so the differences in pressure distribution are relatively small.

  14. [Regulation of geochemical activity of microorganisms in a petroleum reservoir by injection of H2O2 or water-air mixture].

    Science.gov (United States)

    Nazina, T N; Pavlova, N K; Ni, F; Shestakova, N M; Ivoĭlov, V S; Feng, Q; Dongyun, Z; Prusakova, T S; Beliaev, S S; Ivanov, M V

    2008-01-01

    In the course of pilot trials of biotechnologies for the enhancement of oil recovery in the Gangxi bed of the Dagang oil field (China), microbiological processes were investigated. The biotechnologies were based on injection into the petroleum reservoir of different oxygen sources (H2O2 solution or a water-air mixture) with nitrogen and phosphorus salts. The injection of water-air mixture with nitrogen and phosphorus salts resulted in an increase in the number of aerobic and anaerobic organotrophic bacteria, rates of sulfate reduction and methanogenesis in formation water and also the content of CO2 (from 4.8-12 to 15-23.2%) and methane (from 86-88 to 91.8%) in the gas. The preferential consumption of isotopically light bicarbonate by methanogens resulted in a higher content of the light 12C in methane; the delta13C/CH4 value changed from -45.1...-48.3 to -50.7...-59.3 per thousand). At the same time, mineral carbonates of the formation water became isotopically heavier; the delta13C/Sigmacarbonates value increased from 3.4...4.0 to 5.4...9.6 per thousand. Growth of hydrocarbon-oxidizing bacteria was accompanied by production of biosurfactants and decreased interfacial tension of formation water. Injection of H2O2 solution resulted in the activation of aerobic processes and in suppression of both sulfate reduction and methanogenesis. Methane content in the gas decreased from 86-88 to 75.4-79.8%, probably due to its consumption by methanotrophs. Due to consumption of isotopically light methane, the residual methane carbon became heavier, with the delta13C/CH4 values from -39.0 to -44.3 per thousand. At the same time, mineral carbonates of the formation water became isotopically considerably lighter; the delta13C/Sigmacarbonates value decreased from 5.4... 9.6 to -1.4...2.7 per thousand). The additional amount of oil recovered during the trial of both variants of biotechnological treatment was 3819 t.

  15. Improving Students' Understanding of the Connections between the Concepts of Real-Gas Mixtures, Gas Ideal-Solutions, and Perfect-Gas Mixtures

    Science.gov (United States)

    Privat, Romain; Jaubert, Jean-Noël; Moine, Edouard

    2016-01-01

    In many textbooks of chemical-engineering thermodynamics, a gas mixture obeying the fundamental law pV[subscript m] = RT is most often called ideal-gas mixture (in some rare cases, the term perfect-gas mixture can be found). These textbooks also define the fundamental concept of ideal solution which in theory, can be applied indifferently to…

  16. Regeneration of Pt-catalysts deactivated in municipal waste flue gas with H2/N2 and the effect of regeneration step on the SCR catalyst

    DEFF Research Database (Denmark)

    Due-Hansen, Johannes; Rasmussen, Søren Birk; Kustov, Arkadii;

    stream, i.e. by in situ treatment of the Pt-catalyst by reductive H2-gas. However, introduction of H2 gas in the gas stream could also affect other units in the tail pipe gas cleaning system. Of special interest here, is the effect of hydrogen gas on the performance of the deNOx + SCR catalytic process...

  17. Effects on H(-) production in a multicusp ion source by mixture of H2 with H2O, NH3, CH4, N2H4, and SF6

    Science.gov (United States)

    Orient, O. J.; Chutjian, A.; Leung, K. N.

    1987-01-01

    Effects of H(-) production in a multicusp ion source are measured by separately mixing with hydrogen small amounts (0.33-10 percent) of water, ammonia, methane, and hydrazine these are molecules which produce large amounts of H(-) via dissociative attachment (DA) resonances at higher electron energies. The mixing was done in a separate reservoir, with careful measurement of individual pressures. Experimental enhancements of 1.4 and less were observed, whereas calculated enhancements, using accurate DA cross sections for ground-state H2, should have produced factors of 1.5, 3.0, 1.3, and 2.4 enhancements for water, ammonia methane, and hydrazine, respectively, at a mean electron energy of 1.0 eV in the extraction region. The difference is accounted for by including, in the enhancement calculation, vibrationally and rotationally excited H2 molecules, with v-double prime = 5-11, and J-double prime = 0-5, and the large DA cross sections for the excited H2 (v-double prime, J-double prime). The relative populations of H2 (v-double prime, J-double prime) thus obtained are found to be substantially smaller than those predicted by theoretical calculations. The effect on H(-) current was also studied by mixing small amounts of SF6 with H2. A 1.5 percent mixture was found to reduce the H(-) output by one half.

  18. A feasibility study on the bioconversion of CO2 and H2 to biomethane by gas sparging through polymeric membranes.

    Science.gov (United States)

    Díaz, I; Pérez, C; Alfaro, N; Fdz-Polanco, F

    2015-06-01

    In this study, the potential of a pilot hollow-fiber membrane bioreactor for the conversion of H2 and CO2 to CH4 was evaluated. The system transformed 95% of H2 and CO2 fed at a maximum loading rate of 40.2 [Formula: see text] and produced 0.22m(3) of CH4 per m(3) of H2 fed at thermophilic conditions. H2 mass transfer to the liquid phase was identified as the limiting step for the conversion, and kLa values of 430h(-1) were reached in the bioreactor by sparging gas through the membrane module. A simulation showed that the bioreactor could upgrade biogas at a rate of 25m(3)/mR(3)d, increasing the CH4 concentration from 60 to 95%v. This proof-of-concept study verified that gas sparging through a membrane module can efficiently transfer H2 from gas to liquid phase and that the conversion of H2 and CO2 to biomethane is feasible on a pilot scale at noteworthy load rates.

  19. The fabrication of high sensitivity gold nanorod H2S gas sensors utilizing the highly uniform anodic aluminum oxide template

    Directory of Open Access Journals (Sweden)

    Chien-Yu Li

    2016-12-01

    Full Text Available Gold nanorod were fabricated using anodic alumina oxide template for H2S gas detection. The nanorod gas sensor exhibits high surface density and contact area, which can increase detection sensitivity. The anodic alumina oxide template contains an array of pores, with a width of 70 nm and a length of 27μm. Au nanorod were obtained through electro-deposition under a pulse bias of −1 V. The resistance of the Au nanorod was recorded upon exposure to various concentrations of H2S. The resistance could be attributed to the high electron affinity between sulfide and Au nanorod. Au–sulfide bonds provide strong bonding, which could alter the conductivity of the sensor. The gas sensor exhibits high sensitivity and short response time for H2S detection at room temperature.

  20. The fabrication of high sensitivity gold nanorod H2S gas sensors utilizing the highly uniform anodic aluminum oxide template

    Science.gov (United States)

    Li, Chien-Yu; Li, Ciao-Yu; Wu, You-Lin; Hsu, Chung-Ping; Lee, Ming-Ching; Houng, Mau-Phon

    2016-12-01

    Gold nanorod were fabricated using anodic alumina oxide template for H2S gas detection. The nanorod gas sensor exhibits high surface density and contact area, which can increase detection sensitivity. The anodic alumina oxide template contains an array of pores, with a width of 70 nm and a length of 27 μ m . Au nanorod were obtained through electro-deposition under a pulse bias of -1 V. The resistance of the Au nanorod was recorded upon exposure to various concentrations of H2S. The resistance could be attributed to the high electron affinity between sulfide and Au nanorod. Au-sulfide bonds provide strong bonding, which could alter the conductivity of the sensor. The gas sensor exhibits high sensitivity and short response time for H2S detection at room temperature.

  1. Effect of a gas-gas-heater on H2SO4 aerosol formation: implications for mist formation in amine based carbon capture

    NARCIS (Netherlands)

    Mertens, J.; Bruns, R.; Schallert, B.; Faniel, N.; Khakharia, P.M.; Albrecht, W.; Goetheer, E.L.V.; Blondeau, J.; Schaber, K.

    2015-01-01

    This study is to our knowledge the first to describe the effect of a Gas-Gas Heater (GGH) of a coal fired power plant's has on (i) the H2SO4 concentration and (ii) the particle/aerosol number concentration and particle size distribution present in the flue gas. In the absence of a GGH, homogenous nu

  2. Comparative sterilization effectiveness of plasma in O2-H2O2 mixtures and ethylene oxide treatment.

    Science.gov (United States)

    Silva, J M F; Moreira, A J; Oliveira, D C; Bonato, C B; Mansano, R D; Pinto, T J A

    2007-01-01

    We investigated the influence of variable parameters of plasma sterilization and compared its effectiveness with that of ethylene oxide using a reactive ion etching plasma reactor at 13.56 MHz. Gases tested were pure oxygen and oxygen-hydrogen peroxide mixtures in 190/10, 180/20, and 160/40 sccm ratios with constant gas flow at 200 sccm, pressure at 0.100 torr, radio-frequency power at 25 W, 50 W, 100 W, and 150 W, and temperature below 60 degrees C. Ethylene oxide sterilization was performed using 450 mg/L at 55 degrees C, 60% humidity, and -0.65 and 0.60 kgf/cm2 pressure. The biological indicator was Bacillus atrophaeus ATCC 9372, with exposure times of 3 to 120 min. Observed D values were 215.91, 55.55, 9.19, and 2.98 min for pure oxygen plasma at 25 W, 50 W, 100 W, and 150 W, respectively. Oxygen-hydrogen peroxide plasma produced D values of 6.41 min (190/10), 6.47 min (180/20), and 4.02 min (160/40) at 100 W and 1.47 min (190/10), 3.11 min (180/20), and 1.94 min (160/40) at 150 W. Ethylene oxide processes resulted in a D value of 2.86 min. Scanning electron microscopy analyses showed damage to the spore cortex.

  3. Simulation of Pore Width and Pore Charge Effects on Selectivities of CO2 vs. H2 from a Syngas-like Mixture in Carbon Mesopores

    NARCIS (Netherlands)

    Trinh, T.T.; Vlugt, T.J.H.; Hägg, M.B.; Bedeaux, D.; Kjelstrup, S.

    2014-01-01

    Classical molecular dynamics simulations were performed to study the effect of pore width and surface charge in carbon mesoporous materials on adsorption and diffusion selectivities of CO2/H2 in a syngas-like mixture (mole fraction of CO2 = 0.30). The pore width of the graphite slit varied from 2.5

  4. Role of the Material Electrodes on Resistive Behaviour of Carbon Nanotube-Based Gas Sensors for H2S Detection

    Directory of Open Access Journals (Sweden)

    M. Lucci

    2012-01-01

    Full Text Available Miniaturized gas-sensing devices that use single-walled carbon nanotubes as active material have been fabricated using two different electrode materials, namely, Au/Cr and NbN. The resistive sensors have been assembled aligning by dielectrophoresis the nanotube bundles between 40 μm spaced Au/Cr or NbN multifinger electrodes. The sensing devices have been tested for detection of the H2S gas, in the concentration range 10–100 ppm, using N2 as carrier gas. No resistance changes were detected using sensor fabricated with NbN electrodes, whereas the response of the sensor fabricated with Au/Cr electrodes was characterized by an increase of the resistance upon gas exposure. The main performances of this sensor are a detection limit for H2S of 10 ppm and a recovery time of few minutes. The present study suggests that the mechanism involved in H2S gas detection is not a direct charge transfer between molecules and nanotubes. The hypothesis is that detection occurs through passivation of the Au surfaces by H2S molecules and modification of the contact resistance at the Au/nanotube interface.

  5. 纳米WO3-ZnS系H2S气敏元件的研究%Study on H2S gas sensor of WO3-ZnS nanosized material

    Institute of Scientific and Technical Information of China (English)

    黄世震; 林伟; 陈伟; 陈知前

    2001-01-01

    The H2S gas sensor is made by nanosized WO3 doped with SnO2, ZnS. It shows that ZnS-WO3 gas sensor to H2S has high sensitivity and good selectivity.%以纳米WO3材料,分别掺入SnO2、ZnS,制备成H2S气敏元件。实验表明,当WO3掺入适量ZnS,元件对H2S气体具有较高的灵敏度及选择性。

  6. Origin of natural sulphur-bearing immiscible inclusions and H2S in oolite gas reservoir, Eastern Sichuan

    Institute of Scientific and Technical Information of China (English)

    LIU; Dehan; XIAO; Xianming; XIONG; Yongqiang; GENG; Ansong; TIAN; Hui; PENG; Ping'an; SHEN; Jiagui; WANG; Yunpeng

    2006-01-01

    Based on results of microscopic observation and laser Raman analysis about fluid inclusions, multiple special forms of immiscible inclusions that contain sulphur, liquid hydrocarbon, bitumen, etc. were discovered in samples collected from the H2S gas reservoir-containing carbonates in the Lower Triassic Feixianguan Formation in the Jinzhu-Luojia area, Kai County, Sichuan Province. Based on the lithology and burial history of the strata involved as well as measurement results of homogenization temperature of fluid inclusions, bitumen reflectivity, etc., it is concluded that the H2S in the gas reservoir resulted from the thermal reaction between hydrocarbons in reservoir and CaSO4 in the gypsum-bearing dolostone section at the high temperature (140℃―170℃) oil-cracked gas formation stage in Late Cretaceous. Thereafter, research on a great number of immiscible inclusions in the reservoir reveals that elemental sulphur resulted from oxidation of part of the earlier-formed H2S and further reaction between sulphates, hydrocarbons and H2S in geological fluids in H2S-bearing gas reservoir at a temperature of 86℃―89℃ and a pressure of 340×105Pa and during the regional uplift stage as characterized by temperature decrease and pressure decrease in Tertiary. Meanwhile, gypsum, anhydrite and calcite formed at this stage would trap particles like elemental sulphur and result in a variety of special forms of immiscible inclusions, and these inclusions would contain information concerning the complexity of the fluids in the reservoir and the origin of H2S and natural sulphur in the gas reservoir.

  7. Near-Infrared Band Strengths of Molecules Diluted in N2 and H2O Ice Mixtures Relevant to Interstellar and Planetary Ices

    Science.gov (United States)

    Richey, Christina Rae; Gerakines, P.A.

    2012-01-01

    The relative abundances of ices in astrophysical environments rely on accurate laboratory measurements of physical parameters, such as band strengths (or absorption intensities), determined for the molecules of interest in relevant mixtures. In an extension of our previous study on pure-ice samples, here we focus on the near-infrared absorption features of molecules in mixtures with the dominant components of interstellar and planetary ices, H2O and N2. We present experimentally measured near-infrared spectral information (peak positions, widths, and band strengths) for both H2O- and N2-dominated mixtures of CO (carbon monoxide), CO2 (carbon dioxide), CH4 (methane), and NH3 (ammonia). Band strengths were determined during sample deposition by correlating the growth of near-infrared features (10,000-4000 per centimeter, 1-2.5 micrometers) with better-known mid-infrared features (4000-400 per centimeter, 2.5-25 micrometers) at longer wavelengths.

  8. Hydrogen sulfide (H2S) - the third gas of interest for pharmacologists.

    Science.gov (United States)

    Łowicka, Ewelina; Bełtowski, Jerzy

    2007-01-01

    Nitric oxide (NO) and carbon monoxide (CO) synthesized from L-arginine by NO synthase and from heme by heme oxygenase, respectively, are the well-known neurotransmitters and are also involved in the regulation of vascular tone. Recent studies suggest that hydrogen sulfide (H(2)S) is the third gaseous mediator in mammals. H(2)S is synthesized from L-cysteine by either cystathionine beta-synthase (CBS) or cystathionine gamma-lyase (CSE), both using pyridoxal 5'-phosphate (vitamin B(6)) as a cofactor. H(2)S stimulates ATP-sensitive potassium channels (K(ATP)) in the vascular smooth muscle cells, neurons, cardiomyocytes and pancreatic beta-cells. In addition, H(2)S may react with reactive oxygen and/or nitrogen species limiting their toxic effects but also, attenuating their physiological functions, like nitric oxide does. In contrast to NO and CO, H(2)S does not stimulate soluble guanylate cyclase. H(2)S is involved in the regulation of vascular tone, myocardial contractility, neurotransmission, and insulin secretion. H(2)S deficiency was observed in various animal models of arterial and pulmonary hypertension, Alzheimer's disease, gastric mucosal injury and liver cirrhosis. Exogenous H(2)S ameliorates myocardial dysfunction associated with the ischemia/reperfusion injury and reduces the damage of gastric mucosa induced by anti-inflammatory drugs. On the other hand, excessive production of H(2)S may contribute to the pathogenesis of inflammatory diseases, septic shock, cerebral stroke and mental retardation in patients with Down syndrome, and reduction of its production may be of potential therapeutic value in these states.

  9. Using Gas Chromatography/Isotope Ratio Mass Spectrometry to Determine the Fractionation Factor for H2 Production by Hydrogenases

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hui; Ghandi, H.; Shi, Liang; Kreuzer, Helen W.; Ostrom, Nathaniel; Hegg, Eric L.

    2012-01-15

    Hydrogenases catalyze the reversible formation of H2, and they are key enzymes in the biological cycling of H2. H isotopes should be a very useful tool in quantifying proton trafficking in biological H2 production processes, but there are several obstacles that have thus far limited the use of this tool. In this manuscript, we describe a new method that overcomes some of these barriers and is specifically designed to measure isotopic fractionation during enzyme-catalyzed H2 evolution. A key feature of this technique is that purified hydrogenases are employed, allowing precise control over the reaction conditions and therefore a high level of precision. A custom-designed high-throughput gas chromatography-isotope ratio mass spectrometer is employed to measure the isotope ratio of the H2. Using this method, we determined that the fractionation factor of H2 production by the [NiFe]-hydrogenase from Desulfivibrio fructosovran is 0.27. This result indicates that, as expected, protons are highly favored over deuterons during H2 evolution. Potential applications of this new method are discussed.

  10. Interstellar ice analogs: H2O ice mixtures with CH3OH and NH3 in the far-IR region

    Science.gov (United States)

    Giuliano, B. M.; Martín-Doménech, R.; Escribano, R. M.; Manzano-Santamaría, J.; Muñoz Caro, G. M.

    2016-08-01

    Context. New spectroscopic observations in the far-infrared (IR) range are expected from future planned missions. Although water ice is the only species detected so far in interstellar ices in this range, the presence of ice mixtures requires laboratory characterization of the corresponding spectra. Aims: We present an investigation on far-IR spectra of binary ice mixtures relevant in various astrophysical environments. The foremost goal is to compare the spectroscopic features of the ice mixtures to those of pure ices, and to search for changes in peak frequencies, intensities, and band strengths of the main bands. Methods: Mixtures H2O:CH3OH and H2O:NH3 of different ratios have been deposited on a diamond substrate at astrophysically relevant conditions. We measured the spectra in the near- and mid-IR regions to derive ice column densities that were subsequently used to calculate the apparent band strengths in the far-IR region. We also designed theoretical models to study these mixtures and to predict their spectra. Results: We recorded spectra of amorphous phases for H2O:CH3OH mixtures of different compositions, that is 1:1, 3:1, and 10:1 at 8 K, and compared these mixtures to those obtained after warming. This process involves the appearance of new spectral features and changes in band shapes and band strengths. We also compared the spectra to those of the pure species and to theoretical predictions. We measured apparent band strengths for all the observed features. For H2O:NH3 mixtures, the ratios selected were 3:1, 1:1, and 1:3. In this case the spectral variations are even more marked than for the water:methanol samples. Conclusions: Band strengths in the far-IR are missing in astrophysics literature for ice mixtures. The results presented here are valuable for detecting the presence and composition of such mixtures from future space observations in this spectral region.

  11. Photocatalytic H2 Production Using Pt-TiO2 in the Presence of Oxalic Acid: Influence of the Noble Metal Size and the Carrier Gas Flow Rate

    Directory of Open Access Journals (Sweden)

    Ákos Kmetykó

    2014-10-01

    Full Text Available The primary objective of the experiments was to investigate the differences in the photocatalytic performance when commercially available Aeroxide P25 TiO2 photocatalyst was deposited with differently sized Pt nanoparticles with identical platinum content (1 wt%. The noble metal deposition onto the TiO2 surface was achieved by in situ chemical reduction (CRIS or by mixing chemically reduced Pt nanoparticle containing sols to the aqueous suspensions of the photocatalysts (sol-impregnated samples, CRSIM. Fine and low-scale control of the size of resulting Pt nanoparticles was obtained through variation of the trisodium citrate concentration during the syntheses. The reducing reagent was NaBH4. Photocatalytic activity of the samples and the reaction mechanism were examined during UV irradiation (λmax = 365 nm in the presence of oxalic acid (50 mM as a sacrificial hole scavenger component. The H2 evolution rates proved to be strongly dependent on the Pt particle size, as well as the irradiation time. A significant change of H2 formation rate during the oxalic acid transformation was observed which is unusual. It is probably regulated both by the decomposition rate of accumulated oxalic acid and the H+/H2 redox potential on the surface of the catalyst. The later potential is influenced by the concentration of the dissolved H2 gas in the reaction mixture.

  12. Nitriding of titanium and its alloys by N2, NH3 or mixtures of N2 + H2 in a dc arc plasma at low pressures ( or = to torr)

    Science.gov (United States)

    Avni, R.

    1984-01-01

    The dc glow discharges in different gas mixtures of Ar + N2, Ar + NH3 or Ar + N2 + H2 result in the surface nitriding of Ti metal and its alloy (Ti6Al4V). Various gas mixtures were used in order to establish the main active species governing the nitriding process, i.e., N, N2, NH, or NH2 as excited or ionized particles. The dc discharge was sampled and analyzed by quadruple mass spectrometry (QPMS) and optical emission spectroscopy (OES), and the nitrided samples were analyzed by scanning electron microscopy (SEM) with an EDAX attachment, microhardness, and Fourier transform infrared reflectance spectrometry (FTIR). It was found that the excited and ionized nitrogen and hydrogen atoms are the main species responsible for the nitriding process in a dc glow discharge.

  13. Flame-Made Pt-Loaded TiO2 Thin Films and Their Application as H2 Gas Sensors

    Directory of Open Access Journals (Sweden)

    Weerasak Chomkitichai

    2013-01-01

    Full Text Available The hydrogen gas sensors were developed successfully using flame-made platinum-loaded titanium dioxide (Pt-loaded TiO2 nanoparticles as the sensing materials. Pt-loaded TiO2 thin films were prepared by spin-coating technique onto Al2O3 substrates interdigitated with Au electrodes. Structural and gas-sensing characteristics were examined by using scanning electron microscopy (SEM and showed surface morphology of the deposited film. X-ray diffraction (XRD patterns can be confirmed to be the anatase and rutile phases of TiO2. High-resolution transmission electron microscopy (HRTEM showed that Pt nanoparticles deposited on larger TiO2 nanoparticles. TiO2 films loaded with Pt nanoparticles were used as conductometric sensors for the detection of H2. The gas sensing of H2 was studied at the operating temperatures of 300, 350, and 400°C in dry air. It was found that 2.00 mol% Pt-loaded TiO2 sensing films showed higher response towards H2 gas than the unloaded film. In addition, the responses of Pt-loaded TiO2 films at all operating temperatures were higher than that of unloaded TiO2 film. The response increased and the response time decreased with increasing of H2 concentrations.

  14. Gas gain study for CO sub 2 /isobutane mixtures

    CERN Document Server

    Okuno, H; Nakamura, Y; Fujii, K; Hoshina, K; Kato, Y; Kurihara, Y; Kuroiwa, H; Nitoh, O

    2000-01-01

    We have studied gas amplification properties of a proportional tube filled with CO sub 2 /isobutane gas mixtures. The gas gain was measured for X- and beta-rays as a function of the anode-wire surface field and was used to estimate gain variation along 4.6 m-long stereo anode wires of our proposed central drift chamber for JLC. During the gas gain study, we observed a strong saturation effect for point ionizations.

  15. Analysis of Morphology of Oblique Detonation Wave in H2-Air Mixture%氢-空气斜爆震波的极曲线分析

    Institute of Scientific and Technical Information of China (English)

    伍智超; 郭印诚

    2012-01-01

    本文建立了一种以温度为单变量进行迭代,求解真实气体模型下的斜爆震波波后参数非线性方程组的方法。并通过以加热量和气流偏转角为变量,计算出对应斜爆震波角度和斜爆震波的驻定范围。对于给定的来流条件,基于真实气体模型的斜爆震波的驻定范围比量热完全气体的宽,所以在斜爆震波的计算中必须考虑热物性的影响。随着氢气和空气化学当量比的增加,斜爆震波驻定范围逐步变小。而来流马赫数越大,斜爆震波的驻定范围越大,其CJ爆震波对应的平面偏转角越小。来流初温的升高则使斜爆震波的驻定范围变宽。斜爆震波的驻定需要来流条件与斜面角度等因素的相互匹配。%A numerical method of single variable iteration by temperature for solving nonlinear equations of real gas model was developed. Theoretical analysis gives effect of different heat flux and deflection angles of gas on the angle of oblique detonation wave(ODW). For a given H2-air mixture flow, the standing range of the oblique detonation wave predicted by the real gas model is larger than that by the calorically perfect gas model, this indicates that the thermal property should be considered when calculating an oblique detonation wave. With the equivalence ratio of hydrogen to air increasing, the standing range of the oblique detonation wave is changing small. With the Mach number of oncoming flow increasing, the standing range of the oblique detonation wave increases, and the minimum turning angles of Chapman-Jouguet states decrease. The increased temperature of oncoming flow is beneficial to promote the standing range of the oblique detonation wave. The standing ability of oblique detonation wave relates to the oncoming flow condition and the angle of wedge.

  16. 煤矿井下喷雾吸收H2S技术研究%Research on Absorption H2S Gas by Spray in Underground Coal Mine

    Institute of Scientific and Technical Information of China (English)

    宋超; 陈通; 王鹏; 王小军; 冯海

    2015-01-01

    首先对喷雾吸收药剂进行了对比优选,得出了质量浓度为1%的Na2CO3溶液用于井下H2S气体治理效果最佳。然后优选了干雾级喷雾装置用于井下H2S气体治理,并进行了现场试验研究。试验结果表明:经喷雾试验后,H2S气体浓度由6×10-6降至1×10-6,H2S去除率达83%,通过喷雾吸收H2S技术能够有效治理矿井H2S气体灾害。%First of all, spray absorption agents were compared and prioritized to obtain that mass concentration of 1% sodium carbonate solution for underground H2S gas treatment was the best. Then optimized for a dry mist spray apparatus for underground H2S gas treatment, and in-situ experimental study was conducted. The results show that:after spray test, H2S gas concentrations decreased from 6×10-6 to 1×10-6, which means that the removal rate of H2S was 83%.The spray absorption H2S technology can effectively govern the mine disasters of H2S gas.

  17. Photocatalytic oxidation of H2S in the gas phase over TiO2-coated glass fiber filter.

    Science.gov (United States)

    Brancher, Marlon; Franco, Davide; de Melo Lisboa, Henrique

    2016-11-01

    To promote the photocatalytic oxidation (PCO) of hydrogen sulfide (H2S) in the gas phase, TiO2-coated glass fiber filters were packed in an annular photoreactor. Glass fibers coated with TiO2 thin films were characterized structurally and morphologically by field emission gun scanning electron microscopy (FEG-SEM), scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS) and X-ray diffractometry (XRD). Flow rate and H2S inlet concentration were evaluated to determine the performance of the reactor. Removal efficiencies up to 99% were achieved for flow rate of 25 L h(-1) (residence time of 121 s) and H2S inlet concentration from 12 to 14 ppmv. The long-term experiment presented H2S removal of 89% for 16 h. After 28 h of continuous use, H2S degradation was observed at 64%, which suggests that the photocatalyst was losing activity due to deactivation. Moreover, the kinetics of the PCO of H2S according to the Langmuir-Hinshelwood (L-H) approach along with the mass balance of a plug-flow reactor was modeled. The reaction constant (k) was calculated at approximately 10.5 μmol m(-3) s(-1) and the adsorption constant (K) of approximately 5263 m(-3) mol with linearity (R2) of 0.98.

  18. Studies of purification of the Resistive Plate Chamber gas mixture for the Large Hadron Collider experiments

    CERN Document Server

    Capeans, M; Guida, R; Hahn, F; Haider, S

    2009-01-01

    The Resistive Plate Chambers (RPCs) installed as part of the large muon detectors at the Large Hadron Collider (LHC) experiments use a gas mixture of 94.7% C2H2F4, 5% iC(4)H(10) and 0.3% SF6. Based on economical grounds, the design philosophy of the gas systems for the ATLAS and CMS RPC's foresees to recirculate the gas mixture in 90-95% closed loop circulation. At the LHC, RPC chambers are operated in a high radiation environment, conditions for which large amount of impurities in the return gas have been observed in earlier studies. They are potentially dangerous for the stable operation of the detectors, the materials in the detector and the gas system. While several purification stages have been foreseen in the present gas systems, chemical reactions between the absorber and the impurities are yet not well understood. Furthermore, the effects on the gas mixture of the foreseen factor 10 increase of luminosity for the LHC upgraded phase should be studied. We present the results of systematic studies of the...

  19. H2S燃料电池的研究进展%Research Advances in Treatment of Gas Containing H2S with Fuel Cell Technology

    Institute of Scientific and Technical Information of China (English)

    谭文轶; 钟秦

    2006-01-01

    H2S燃料电池是一种环境友好、发电效率较高并且同时共生其他化学产品的装置,为含H2S气体的处理提供了新的思路.按照采用的固体电解质的导电粒子的不同阐释了H2S的电化学氧化基本原理,指出对H2S燃料电池的电化学氧化机理的研究将进一步扩大H2S资源化利用的范围,以实现H2S燃料电池电能与化学产品的同步生产.目前H2S燃料电池固体电解质薄膜和阳极电催化剂的研制及其一体化技术是H2S燃料电池的关键.

  20. Volumetric Properties of the Mixture Trichloromethane CHCl3 + C2H2Cl4 1,1,2,2-Tetrachloroethane (VMSD1212, LB4572_V)

    Science.gov (United States)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Trichloromethane CHCl3 + C2H2Cl4 1,1,2,2-Tetrachloroethane (VMSD1212, LB4572_V)' providing data by calculation of molar excess volume from low-pressure density measurements at variable mole fraction and constant temperature.

  1. Survival of Campylobacter jejuni in different gas mixtures

    DEFF Research Database (Denmark)

    Boysen, Louise; Knochel, Susanne; Rosenquist, Hanne

    2007-01-01

    Campylobacter jejuni in fresh chilled chicken meat is known to be a major risk factor for human gastrointestinal disease. In the present study, the survival under chilled conditions of different C. jejuni strains exposed to different gas mixtures usually used for gas packaging of food was examined...

  2. Characterisation of Oil-Gas Mixtures by Raman Spectroscopy

    DEFF Research Database (Denmark)

    Hansen, Susanne Brunsgaard; Berg, Rolf W.; Stenby, Erling Halfdan

    2004-01-01

    . The present project deals with development of a technique for quick analysis of oil-gas mixtures. The main emphasis is laid on characterisation of gas phases in equilibrium with oil at high pressures and high temperatures by Raman spectroscopy. The Raman technique has a great potential of being useful, due...

  3. Characterisation of Oil-Gas Mixtures by Raman Spectroscopy

    DEFF Research Database (Denmark)

    Hansen, Susanne Brunsgaard; Berg, Rolf W.; Stenby, Erling Halfdan

    2004-01-01

    . The present project deals with development of a technique for quick analysis of oil-gas mixtures. The main emphasis is laid on characterisation of gas phases in equilibrium with oil at high pressures and high temperatures by Raman spectroscopy. The Raman technique has a great potential of being useful, due...

  4. Time-resolved OES of nanosecond pulsed discharges in N$_{2}$ and N$_{2}$/H$_{2}$O mixtures]{Time-resolved optical emission spectroscopy of nanosecond pulsed discharges in atmospheric pressure N$_{2}$ and N$_{2}$/H$_{2}$O mixtures

    CERN Document Server

    van der Horst, R M; van Veldhuizen, E M; Bruggeman, P J

    2014-01-01

    In this contribution, nanosecond pulsed discharges in N$_{2}$ and N$_{2}$/0.9% H$_{2}$O at atmospheric pressure (at 300 K) are studied with time-resolved imaging, optical emission spectroscopy and Rayleigh scattering. A 170 ns high voltage pulse is applied across two pin-shaped electrodes at a frequency of 1 kHz. The discharge consists of three phases: an ignition phase, a spark phase and a recombination phase. During the ignition phase the emission is mainly caused by molecular nitrogen (N$_{2}$(C-B)). In the spark and recombination phase mainly atomic nitrogen emission is observed. The emission when H$_{2}$O is added is very similar, except the small contribution of H$_{\\alpha}$ and the intensity of the molecular N$_{2}$(C-B) emission is less.

  5. Formation of (HCOO-)(H2SO4) Anion Clusters: Violation of Gas Phase Acidity Predictions

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Gao-Lei; Wang, Xue-Bin; Valiev, Marat

    2017-08-23

    Sulfuric acid is commonly known to be a strong acid and, by all counts, should readily donate its proton to formate, which has much higher proton affinity. This conventional wisdom is challenged in this work, where temperature-dependent negative ion photoelectron spectroscopy (NIPES) and theoretical studies demonstrate the existence of (HCOO?)(H2SO4) pair at the energy slightly below the conventional (HCOOH)(HSO4?) structure. Analysis of quantum-mechanical calculations indicates that large proton affinity barrier (~36 kcal/mol), favoring proton transfer to formate, is offset by the gain in inter-molecular interaction energy between HCOO? and H2SO4 through the formation of two strong hydrogen bonds. However, this stabilization comes with severe entropic penalty, requiring the two species in the precise align-ment. As a result, the population of (HCOO?)(H2SO4) drops significantly at higher temperatures, rendering (HCOOH)(HSO4?) to be the dominant species. This phe-nomenon is consistent with the NIPES data, which shows depletion in the spectra assigned to (HCOO?)(H2SO4), and has also been verified by ab initio molecular dynamics simulations.

  6. Separation of CO2 and H2 Mixed Gas with Ionic liquid Membrane%离子液膜分离CO2、H2混合气体研究

    Institute of Scientific and Technical Information of China (English)

    仲惟

    2016-01-01

    Ionic liquid [BMIM]Cl and NaBF4 was selected to synthesize [BMIM]BF4 in methanol. After OH anion exchange resin exchange, ionic liquid [BMIM]Cl was neutralized with formic acid to prepare [BMIM] HCOO. Three kinds of polymer film PVDF, PAN and PS, and four kinds of ionic liquid [BMIM] BF4, HCOO [BMIM], [BMIM] PF6 and [BMIM] CH3COO were chosed to prepare 12 kinds of supported liquid membranes. At 30℃, 40℃ and 50℃, the CO2and H2single gas permeability of 12 kinds of liquid film were test. The results showed: at 30℃, the CO2 and H2 separation performance of [BMIM] BF4 polysulfone membrane was good, separation factor was more than 14; separation factor of [BMIM] PF6 type polyacrylonitrile membrane was more than 12 at 30℃; the separation factor of [BMIM] PF6 type polyvinylidene fluoride membrane was more than 5 at 30℃. So these three kinds of ionic liquid film had a certain separation degree for CO2 and H2 gas mixture at 30℃.%选用离子液体[BMIM]Cl与NaBF4在甲醇中反应制得[BMIM]BF4,离子液体[BMIM]Cl经OH型阴离子交换树脂交换后再与甲酸进行中和制得[BMIM]HCOO。分别选用3种聚合物薄膜PVDF、PAN和PS,使其与4种离子液体[BMIM] BF4、[BMIM]HCOO、[BMIM]PF6和[BMIM]CH3COO共制成12种支撑液膜。在30℃、40℃和50℃时分别进行12种液膜的CO2、H2单一气体渗透性测试。结果显示,[BMIM]BF4型聚砜膜在30℃时对CO2与H2分离性能较好,分离系数达14以上;[BMIM]PF6型聚丙烯腈膜在30℃时分离系数达12以上;[BMIM]PF6型聚偏氟乙烯膜在30℃时分离系数达到5以上。因此这3种离子液膜在30℃时可对CO2、H2混合气体进行一定程度的分离。

  7. 西曲矿9#煤H2S气体治理%H2S Gas Treatment of 9# Coal Seam in Xiqu Coal Mine

    Institute of Scientific and Technical Information of China (English)

    张崇智; 王林中

    2007-01-01

    分析了西曲矿9#煤层H2S气体形成的原因,并介绍了深孔脉冲动压注碱技术在19102工作面的应用.简述了在开采9#煤过程中治理H2S气体所采取的措施及具体做法,可为矿井治理H2S气体提供借鉴的经验.

  8. Search for cold gas in z>2 damped Lyman-alpha systems: 21-cm and H_2 absorption

    CERN Document Server

    Srianand, R; Petitjean, P; Noterdaeme, P; Ledoux, C; Salter, C J; Saikia, D J

    2011-01-01

    (Abridged) We present the results of a systematic GBT and GMRT survey for 21-cm absorption in a sample of 10 DLAs at 2 2 is predominantly constituted by WNM. The detection rate of 21-cm absorption seems to be higher for systems with higher N(HI) or metallicity. However, no clear correlation is found between the integrated 21-cm optical depth (or spin temperature) and either N(HI), metallicity or velocity spread of the low ionization species. There are 13 DLAs in our sample for which high resolution optical spectra covering the expected wavelength range of H_2 absorption are available. We report the detection of H_2 molecules in the z_abs = 3.3871 21-cm absorber towards J0203+1134 (PKS 0201+113). In 8 cases, neither H_2 nor 21-cm absorption are detected. The lack of 21-cm and H_2 absorption in these systems can be explained if most of the HI in these DLAs originate from low density high temperature gas. In one case we have a DLA with 21-cm absorption not showing H_2 absorption. In two cases, both species are d...

  9. Optimization of operating parameters for gas-phase photocatalytic splitting of H2S by novel vermiculate packed tubular reactor.

    Science.gov (United States)

    Preethi, V; Kanmani, S

    2016-10-01

    Hydrogen production by gas-phase photocatalytic splitting of Hydrogen Sulphide (H2S) was investigated on four semiconductor photocatalysts including CuGa1.6Fe0.4O2, ZnFe2O3, (CdS + ZnS)/Fe2O3 and Ce/TiO2. The CdS and ZnS coated core shell particles (CdS + ZnS)/Fe2O3 shows the highest rate of hydrogen (H2) production under optimized conditions. Packed bed tubular reactor was used to study the performance of prepared photocatalysts. Selection of the best packing material is a key for maximum removal efficiency. Cheap, lightweight and easily adsorbing vermiculate materials were used as a novel packing material and were found to be effective in splitting H2S. Effect of various operating parameters like flow rate, sulphide concentration, catalyst dosage, light irradiation were tested and optimized for maximum H2 conversion of 92% from industrial waste H2S.

  10. Molecular dynamics investigation of separation of hydrogen sulfide from acidic gas mixtures inside metal-doped graphite micropores.

    Science.gov (United States)

    Huang, Pei-Hsing

    2015-09-21

    The separation of poisonous compounds from various process fluids has long been highly intractable, motivating the present study on the dynamic separation of H2S in acidic-gas-mixture-filled micropores. The molecular dynamics approach, coupled with the isothermal-isochoric ensemble, was used to model the molecular interactions and adsorption of H2S/CO2/CO/H2O mixtures inside metal-doped graphite slits. Due to the difference in the adsorption characteristics between the two distinct adsorbent materials, the metal dopant in the graphitic micropores leads to competitive adsorption, i.e. the Au and graphite walls compete to capture free adsorbates. The effects of competitive adsorption, coupled with changes in the gas temperature, concentration, constituent ratio and slit width on the constituent separation of mixtures were systematically studied. The molecule-wall binding energies calculated in this work (those of H2S, H2O and CO on Au walls and those of H2O, CO and CO2 on graphite walls) show good agreement with those obtained using density functional theory (DFT) and experimental results. The z-directional self-diffusivities (Dz) for adsorbates inside the slit ranged from 10(-9) to 10(-7) m(2) s(-1) as the temperature was increased from 10 to 500 K. The values are comparable with those for a typical microporous fluid (10(-8)-10(-9) m(2) s(-1) in a condensed phase and 10(-6)-10(-7) m(2) s(-1) in the gaseous state). The formation of H-bonding networks and hydrates of H2S is disadvantageous for the separation of mixtures. The results indicate that H2S can be efficiently separated from acidic gas mixtures onto the Au(111) surface by (i) reducing the mole fraction of H2S and H2O in the mixtures, (ii) raising the gas temperature to the high temperature limit (≥400 K), and (iii) lowering the slit width to below the threshold dimension (≤23.26 Å).

  11. An approach for estimating toxic releases of H2S-containing natural gas.

    Science.gov (United States)

    Jianwen, Zhang; Da, Lei; Wenxing, Feng

    2014-01-15

    China is well known being rich in sulfurous natural gas with huge deposits widely distributed all over the country. Due to the toxic nature, the release of hydrogen sulfide-containing natural gas from the pipelines intends to impose serious threats to the human, society and environment around the release sources. CFD algorithm is adopted to simulate the dispersion process of gas, and the results prove that Gaussian plume model is suitable for determining the affected region of the well blowout of sulfide hydrogen-containing natural gas. In accordance with the analysis of release scenarios, the present study proposes a new approach for estimating the risk of hydrogen sulfide poisoning hazards, as caused by sulfide-hydrogen-containing natural gas releases. Historical accident-statistical data from the EGIG (European Gas Pipeline Incident Data Group) and the Britain Gas Transco are integrated into the approach. Also, the dose-load effect is introduced to exploit the hazards' effects by two essential parameters - toxic concentration and exposure time. The approach was applied to three release scenarios occurring on the East-Sichuan Gas Transportation Project, and the individual risk and societal risk are classified and discussed. Results show that societal risk varies significantly with different factors, including population density, distance from pipeline, operating conditions and so on. Concerning the dispersion process of hazardous gas, available safe egress time was studied from the perspective of individual fatality risks. The present approach can provide reliable support for the safety management and maintenance of natural gas pipelines as well as evacuations that may occur after release incidents.

  12. Testing the accuracy of correlations for multicomponent mass transport of adsorbed gases in metal-organic frameworks: diffusion of H2/CH4 mixtures in CuBTC.

    Science.gov (United States)

    Keskin, Seda; Liu, Jinchen; Johnson, J Karl; Sholl, David S

    2008-08-05

    Mass transport of chemical mixtures in nanoporous materials is important in applications such as membrane separations, but measuring diffusion of mixtures experimentally is challenging. Methods that can predict multicomponent diffusion coefficients from single-component data can be extremely useful if these methods are known to be accurate. We present the first test of a method of this kind for molecules adsorbed in a metal-organic framework (MOF). Specifically, we examine the method proposed by Skoulidas, Sholl, and Krishna (SSK) ( Langmuir, 2003, 19, 7977) by comparing predictions made with this method to molecular simulations of mixture transport of H 2/CH 4 mixtures in CuBTC. These calculations provide the first direct information on mixture transport of any species in a MOF. The predictions of the SSK approach are in good agreement with our direct simulations of binary diffusion, suggesting that this approach may be a powerful one for examining multicomponent diffusion in MOFs. We also use our molecular simulation data to test the ideal adsorbed solution theory method for predicting binary adsorption isotherms and a method for predicting mixture self-diffusion coefficients.

  13. Optimization of an enclosed gas analyzer sampling system for measuring eddy covariance fluxes of H2O and CO2

    Science.gov (United States)

    Metzger, Stefan; Burba, George; Burns, Sean P.; Blanken, Peter D.; Li, Jiahong; Luo, Hongyan; Zulueta, Rommel C.

    2016-03-01

    Several initiatives are currently emerging to observe the exchange of energy and matter between the earth's surface and atmosphere standardized over larger space and time domains. For example, the National Ecological Observatory Network (NEON) and the Integrated Carbon Observing System (ICOS) are set to provide the ability of unbiased ecological inference across ecoclimatic zones and decades by deploying highly scalable and robust instruments and data processing. In the construction of these observatories, enclosed infrared gas analyzers are widely employed for eddy covariance applications. While these sensors represent a substantial improvement compared to their open- and closed-path predecessors, remaining high-frequency attenuation varies with site properties and gas sampling systems, and requires correction. Here, we show that components of the gas sampling system can substantially contribute to such high-frequency attenuation, but their effects can be significantly reduced by careful system design. From laboratory tests we determine the frequency at which signal attenuation reaches 50 % for individual parts of the gas sampling system. For different models of rain caps and particulate filters, this frequency falls into ranges of 2.5-16.5 Hz for CO2, 2.4-14.3 Hz for H2O, and 8.3-21.8 Hz for CO2, 1.4-19.9 Hz for H2O, respectively. A short and thin stainless steel intake tube was found to not limit frequency response, with 50 % attenuation occurring at frequencies well above 10 Hz for both H2O and CO2. From field tests we found that heating the intake tube and particulate filter continuously with 4 W was effective, and reduced the occurrence of problematic relative humidity levels (RH > 60 %) by 50 % in the infrared gas analyzer cell. No further improvement of H2O frequency response was found for heating in excess of 4 W. These laboratory and field tests were reconciled using resistor-capacitor theory, and NEON's final gas sampling system was developed on this

  14. Mechanistic Studies of Methanol Synthesis over Cu from CO/CO2/H2/H2O Mixtures: the Source of C in Methanol and the Role of Water

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yong; Mims, Charles A.; Mei, Donghai; Peden, Charles HF; Campbell, Charles T.

    2013-02-01

    The low temperature (403 – 453K) conversions of CO:hydrogen and CO2:hydrogen mixtures (6 bar total pressure) to methanol over copper catalysts are both assisted by the presence of small amounts of water (mole fraction ~0.04%-0.5%). For CO2:hydrogen reaction mixtures, the water product from both methanol synthesis and reverse water gas shift serves to initiate both reactions in an autocatalytic manner. In the case of CO:D2 mixtures, very little methanol is produced until small amounts of water are added. The effect of water on methanol production is more immediate than in CO2:D2, yet the steady state rates are similar. Tracer experiments in 13CO:12CO2:hydrogen (with or without added water), show that the dominant source of C in the methanol product gradually shifts from CO2 to CO as the temperature is lowered. Cu-bound formate, the major IR visible surface species under CO2:hydrogen, is not visible in CO:moist hydrogen. Though formate is visible in the tracer experiments, the symmetric stretch is absent. These results, in conjunction with recent DFT calculations on Cu(111), point to carboxyl as a common intermediate for both methanol synthesis and reverse water gas shift, with formate playing a spectator co-adsorbate role.

  15. Nanostructured ZrO2 Thick Film Resistors as H2-Gas Sensors Operable at Room Temperature

    Directory of Open Access Journals (Sweden)

    K. M. GARADKAR

    2009-11-01

    Full Text Available Nanostructured ZrO2 powder was synthesized by microwave assisted sol-gel method. The material was characterized by XRD and SEM techniques. X-Ray diffraction studies confirm that a combination of tetragonal and monoclinic zirconia nanoparticles is obtained by using microwave-assisted method. The nanopowder was calcined at an optimized temperature of 400 °C for 3 h. The prepared powder had crystalline size about 25 nm. Thick films of synthesized ZrO2 powder were prepared by screen printing technique. The gas sensing performances of these films for various gases were tested. Films showed highest response to H2 (50 ppm gas at room temperature with poor responses to others (1000 ppm. The quick response and fast recovery are the main features of this sensor. The effects of microstructure, operating temperature and gas concentration on the gas response, selectivity, response time and recovery time of the sensor in the presence of H2 gas and others were studied and discussed.

  16. Detection of H2S gas at lower operating temperature using sprayed nanostructured In2O3 thin films

    Indian Academy of Sciences (India)

    Ramesh H Bari; Parag P Patil; Sharad B Patil; Anil R Bari

    2013-11-01

    Nanostructured indium oxide (In2O3) thin films were prepared by spray pyrolysis (SP) technique. X-ray diffraction (XRD) was used to investigate the structural properties and field emission scanning electron microscopy (FESEM) was used to confirm surface morphology of In2O3 films. Measurement of electrical conductivity and gas sensing performance were conducted using static gas sensing system. Gas sensing performance was studied at different operating temperature in the range of 25–150°C for the gas concentration of 500 ppm. Themaximum sensitivity ( = 79%) to H2S was found at lower temperature of 50 °C. The quick response (4 s) and fast recovery (8 s) are the main features of this film.

  17. Investigating noble gas mixtures for use in TPCs

    Science.gov (United States)

    Jungbluth, Anna

    2017-01-01

    MITPC is a gas-based time projection chamber used for detecting fast, MeV-scale neutrons. MITPC relies on a CCD camera and the TPC (time projection chamber) technique to visualize and reconstruct tracks of neutron-induced nuclear recoils within a chosen gas. The standard version of the detector uses a mixture of 600 torr gas composed of 87.5% helium-4 and and 12.5% tetrafluoromethane (CF4) for precise measurements of the energy and direction of neutron-induced nuclear recoils. Previous studies demonstrated advantages of using neon as a replacement gas for helium-4. This talk will present a discussion of studies performed with helium and neon, as well as argon and krypton as primary neutron targets in the gas mixture with CF4.

  18. Gas mixtures for spark gap closing switches with emphasis on efficiency of operation

    Science.gov (United States)

    Christophorou, L. G.; McCorkle, D. L.; Hunter, S. R.

    The efficient operation of a spark gap closing switch requires a gaseous medium with large breakdown strength, low conduction voltage, and a short formative time lag. Gas properties necessary to achieve these requirements are identified and discussed. Based on available knowledge of such properties, a number of binary (e.g., c-C4F8, or 1-C3F6, or n-C4F10, or C3F8, or C6F6 in Ar or He or H2) and ternary gas mixtures (e.g., c-C4F8, or n-C4F10, or C3F8 in Ar or He + C2H2 or another low ionization onset additive) have been identified which may be suitable for use in spark gap closing switches.

  19. Improvement in methanol production by regulating the composition of synthetic gas mixture and raw biogas.

    Science.gov (United States)

    Patel, Sanjay K S; Mardina, Primata; Kim, Dongwook; Kim, Sang-Yong; Kalia, Vipin C; Kim, In-Won; Lee, Jung-Kul

    2016-10-01

    Raw biogas can be an alternative feedstock to pure methane (CH4) for methanol production. In this investigation, we evaluated the methanol production potential of Methylosinus sporium from raw biogas originated from an anaerobic digester. Furthermore, the roles of different gases in methanol production were investigated using synthetic gas mixtures of CH4, carbon dioxide (CO2), and hydrogen (H2). Maximum methanol production was 5.13, 4.35, 6.28, 7.16, 0.38, and 0.36mM from raw biogas, CH4:CO2, CH4:H2, CH4:CO2:H2, CO2, and CO2:H2, respectively. Supplementation of H2 into raw biogas increased methanol production up to 3.5-fold. Additionally, covalent immobilization of M. sporium on chitosan resulted in higher methanol production from raw biogas. This study provides a suitable approach to improve methanol production using low cost raw biogas as a feed containing high concentrations of H2S (0.13%). To our knowledge, this is the first report on methanol production from raw biogas, using immobilized cells of methanotrophs.

  20. Binderless Composite Electrode Monolith from Carbon Nanotube and Biomass Carbon Activated by H2 SO4 and CO2 Gas for Supercapacitor

    Science.gov (United States)

    Deraman, M.; Ishak, M. M.; Farma, R.; Awitdrus, Taer, E.; Talib, I. A.; Omar, R.

    2011-12-01

    Binderless composite electrodes in the monolithic form prepared from carbon nanotubes (CNTs) and self-adhesive carbon grains (SACG) from fibers of oil palm empty fruit bunch were studied as an electrode in a supercapacitor. The green monoliths (GMs) were prepared from three different types of precursors, SACG, SACG treated with 0.4 Molar H2 SO4 and mixture of SACG and 5% CNTs (by weight) treated with 0.4 Molar H2 SO4 , respectively. These GMs were carbonized at 600 ° C in N2 gas environment and activated by CO2 gas at 800 ° C for 1 hour to produce activated carbon monoliths (ACMs). The properties of the ACMs (density, porosity, microstructure, structure and electrical conductivity) were found affected by CNTs addition and acid treatment. The acid treatment did not improve the electrochemical behavior of the ACMs used as electrodes (specific capacitance, specific energy and specific power of the supercapacitor) in the supercapacitor cells but CNTs addition improves the equivalent series resistance of the cell.

  1. Phase Composition of Ni/Mg1−xNixO as a Catalyst Prepared for Selective Methanation of CO in H2-Rich Gas

    Directory of Open Access Journals (Sweden)

    Mengmeng Zhang

    2015-01-01

    Full Text Available Supported Ni catalysts Ni/Mg1−xNixO were prepared by reducing samples NiO-MgO in H2/N2 mixture gas at 500°C~800°C for selective methanation of CO in H2-rich gas (CO-SMET. The samples NiO-MgO were obtained by heating water slurry of MgO and Ni(NO32 in a rotary evaporator at 80°C and a final calcination in air at 400°C~800°C. X-ray diffraction (XRD and temperature programmed reduction (TPR measurements demonstrate that the samples NiO-MgO were composed of solid solution Mg1−yNiyO as the main phase and a minor amount of NiO at calcination temperature of 400°C, and amount of the NiO was decreased as calcination temperature increased. Phase composition of the catalysts Ni/Mg1−xNixO was estimated by the Rietveld method. Effects of reduction temperature, feed Ni/Mg ratio, and calcination temperature on phase composition and catalytic activity of the catalysts were investigated. It is clear that CO conversion was generally enhanced by an increased amount of metallic Ni of the catalysts.

  2. Optimization of a gas sampling system for measuring eddy-covariance fluxes of H2O and CO2

    Science.gov (United States)

    Metzger, S.; Burba, G.; Burns, S. P.; Blanken, P. D.; Li, J.; Luo, H.; Zulueta, R. C.

    2015-10-01

    Several initiatives are currently emerging to observe the exchange of energy and matter between the earth's surface and atmosphere standardized over larger space and time domains. For example, the National Ecological Observatory Network (NEON) and the Integrated Carbon Observing System (ICOS) will provide the ability of unbiased ecological inference across eco-climatic zones and decades by deploying highly scalable and robust instruments and data processing. In the construction of these observatories, enclosed infrared gas analysers are widely employed for eddy-covariance applications. While these sensors represent a substantial improvement compared to their open- and closed-path predecessors, remaining high-frequency attenuation varies with site properties, and requires correction. Here, we show that the gas sampling system substantially contributes to high-frequency attenuation, which can be minimized by careful design. From laboratory tests we determine the frequency at which signal attenuation reaches 50 % for individual parts of the gas sampling system. For different models of rain caps and particulate filters, this frequency falls into ranges of 2.5-16.5 Hz for CO2, 2.4-14.3 Hz for H2O, and 8.3-21.8 Hz for CO2, 1.4-19.9 Hz for H2O, respectively. A short and thin stainless steel intake tube was found to not limit frequency response, with 50 % attenuation occurring at frequencies well above 10 Hz for both H2O and CO2. From field tests we found that heating the intake tube and particulate filter continuously with 4 W was effective, and reduced the occurrence of problematic relative humidity levels (RH > 60 %) by 50 % in the infrared gas analyser cell. No further improvement of H2O frequency response was found for heating in excess of 4 W. These laboratory and field tests were reconciled using resistor-capacitor theory, and NEON's final gas sampling system was developed on this basis. The design consists of the stainless steel intake tube, a pleated mesh

  3. The influence of SWCNT-metallic nanoparticle mixtures on the desorption properties of milled MgH2 powders.

    Science.gov (United States)

    Amirkhiz, Babak Shalchi; Danaie, Mohsen; Mitlin, David

    2009-05-20

    We have examined the effect of single-walled carbon nanotube (SWCNT)-metallic nanoparticle additions on the hydrogen desorption behavior of MgH(2) after high-energy co-milling. The metallic nanoparticles were the catalysts used for the SWCNT growth. The co-milling consisted of high-energy planetary milling in an inert argon environment of the hydride powder mixed with the SWCNTs. Identically milled pure MgH(2) powders were used as a baseline. The composites were tested using a combined differential scanning calorimeter and thermogravimetric analyzer, while the microstructures were examined using a variety of techniques including x-ray diffraction and transmission electron microscopy (TEM). We found that the SWCNT-nanoparticle additions do have an influence on the desorption kinetics. However, the degree to which they are effective depends on the composite's final state. The optimum microstructure for sorption, obtained after 1 h of co-milling, consists of highly defective SWCNTs in intimate contact with metallic nanoparticles and with the hydride. This microstructure is optimum, presumably because of the dense and uniform coverage of the defective SWCNTs on the MgH(2) surface. Prolonged co-milling of 7 h destroys the SWCNT structure and reduces the enhancement. Even after 72 h of co-milling, when the SWCNTs are completely destroyed, the metallic nanoparticles remain dispersed on the hydride surfaces. This indicates that the metallic nanoparticles alone are not responsible for the enhanced sorption and that there is indeed something catalytically unique about a defective SWCNT-metal combination. Cryo-stage TEM analysis of the hydride powders revealed that they are nanocrystalline and in some cases multiply twinned. To our knowledge this is the first study where the structure of milled alpha- MgH(2) has been directly imaged. Since defects are an integral component of hydride-to-metal phase transformations, such analysis sheds new insight regarding the fundamental

  4. KINETICS OF DIRECT OXIDATION OF H2S IN COAL GAS TO ELEMENTAL SULFUR

    Energy Technology Data Exchange (ETDEWEB)

    K.C. Kwon

    2002-02-01

    Removal of hydrogen sulfide (H{sub 2}S) from coal gasifier gas and sulfur recovery are key steps in the development of Department of Energy's (DOE's) advanced Vision 21 plants that employ coal and natural gas and produce electric power and clean transportation fuels. These Vision 21 plants will require highly clean coal gas with H{sub 2}S below 1 ppm and negligible amounts of trace contaminants such as hydrogen chloride, ammonia, alkali, heavy metals, and particulate. The conventional method of sulfur removal and recovery employing amine, Claus, and tail-gas treatment is very expensive. A second generation approach developed under DOE's sponsorship employs hot-gas desulfurization (HGD) using regenerable metal oxide sorbents followed by Direct Sulfur Recovery Process (DSRP). However, this process sequence does not remove trace contaminants and is targeted primarily towards the development of advanced integrated gasification combined cycle (IGCC) plants that produce electricity (not both electricity and transportation fuels). There is an immediate as well as long-term need for the development of cleanup processes that produce highly clean coal gas for next generation Vision 21 plants. To this end, a novel process is now under development at Research Triangle Institute (RTI) in which the H{sub 2}S in coal gas is directly oxidized to elemental sulfur over a selective catalyst. Such a process is ideally suited for coal gas from commercial gasifiers with a quench system to remove essentially all the trace contaminants except H{sub 2}S. This direct oxidation process has the potential to produce a super clean coal gas more economically than both conventional amine-based processes and HGD/DSRP. The objective of this research is to support the near- and long-term DOE efforts to commercialize this direct oxidation technology. Specifically, we aim to: Measure the kinetics of direct oxidation of H{sub 2}S to elemental sulfur over selective catalysts in the

  5. Systematic study of RPC performances in polluted or varying gas mixtures compositions: an online monitor system for the RPC gas mixture at LHC

    CERN Document Server

    Capeans, M; Mandelli, B

    2012-01-01

    The importance of the correct gas mixture for the Resistive Plate Chamber (RPC) detector systems is fundamental for their correct and safe operation. A small change in the percentages of the gas mixture components can alter the RPC performance and this will rebound on the data quality in the ALICE, ATLAS and CMS experiments at CERN. A constant monitoring of the gas mixture injected in the RPCs would avoid such kind of problems. A systematic study has been performed to understand RPC performances with several gas mixture compositions and in the presence of common gas impurities. The systematic analysis of several RPC performance parameters in different gas mixtures allows the rapid identification of any variation in the RPC gas mixture. A set-up for the online monitoring of the RPC gas mixture in the LHC gas systems is also proposed.

  6. Calculation of gas solubility in the system MDEA-H2O-CO2-H2S%MDEA-H2O-CO2-H2S体系的气体溶解度的计算

    Institute of Scientific and Technical Information of China (English)

    陈健; 密建国; 刘金晨

    2001-01-01

    目前天然气脱碳和脱硫的主要溶剂是醇胺类水溶液,其中最有代表性的是N-甲基二乙醇胺(简称MDEA)。作者采用严格的混合溶剂电解质理论建立的气体吸收溶解度和吸收热的热力学计算模型,可以同时计算CO2、H2S及混合气体在MDEA水溶液中的溶解度,计算值和实验值符合良好%At the momnent,the main solvents for the removal of carbon dioxide and hydrogen sulfide in natural gas are alkanolaminewater solutions,in which the most widely used one is Nmethyldiethanolamine (MDEA)water solution.In this paper,a strict theory for mixed solvent electrolytic solution is used to establish the thermodynamic model for the calculation of gas solubility and absorption heat.This model can calculate gas solubility of CO2,H2S and mixed gases in MDEAH2O solution,and the calculated values are in good agreement with experimental ones.

  7. Disposable, Paper-Based, Inkjet-Printed Humidity and H2S Gas Sensor for Passive Sensing Applications

    Directory of Open Access Journals (Sweden)

    Abdul Quddious

    2016-12-01

    Full Text Available An inkjet-printed, fully passive sensor capable of either humidity or gas sensing is presented herein. The sensor is composed of an interdigitated electrode, a customized printable gas sensitive ink and a specialized dipole antenna for wireless sensing. The interdigitated electrode printed on a paper substrate provides the base conductivity that varies during the sensing process. Aided by the porous nature of the substrate, a change in relative humidity from 18% to 88% decreases the electrode resistance from a few Mega-ohms to the kilo-ohm range. For gas sensing, an additional copper acetate-based customized ink is printed on top of the electrode, which, upon reaction with hydrogen sulphide gas (H2S changes, both the optical and the electrical properties of the electrode. A fast response time of 3 min is achieved at room temperature for a H2S concentration of 10 ppm at a relative humidity (RH of 45%. The passive wireless sensing is enabled through an antenna in which the inner loop takes care of conductivity changes in the 4–5 GHz band, whereas the outer-dipole arm is used for chipless identification in the 2–3 GHz band.

  8. Energetics of the molecular gas in the H_2 luminous radio galaxy 3C 326: Evidence for negative AGN feedback

    CERN Document Server

    Nesvadba, N P H; Salome, P; Guillard, P; Lehnert, M D; Ogle, P; Appleton, P; Falgarone, E; Forets, G Pineau des

    2010-01-01

    We present a detailed analysis of the gas conditions in the H_2 luminous radio galaxy 3C326N at z~0.1, which has a low star formation rate (SFR~0.07 M_sun/yr) in spite of a gas surface density similar to those in starburst galaxies. Its star-formation efficiency is likely a factor ~20-30 lower than those of ordinary star-forming galaxies. Combining new IRAM CO emission-line interferometry with existing Spitzer mid-infrared spectroscopy, we find that the luminosity ratio of CO and pure rotational H_2 line emission is factors 10-100 lower than what is usually found. This may suggest that most of the molecular gas is warm. The Na D absorption-line profile of 3C326N in the optical suggests an outflow with a terminal velocity of ~ -1800 km/s and a mass outflow rate of 30-40 M_sun/yr, which cannot be explained by star formation. The mechanical power implied by the wind, of order 10^43 erg/s, is comparable to the bolometric luminosity of the emission lines of ionized and molecular gas. To explain these observations,...

  9. Effect Of Gas Mixture Composition On Tar Removal Process In A Pulsed Corona Discharge Reactor

    Science.gov (United States)

    Filimonova E.; Naidis, G.

    2010-07-01

    The simulation of naphthalene (C10H8) removal from several gas mixtures (pure nitrogen, mixtures containing N2 with CO2, CO, H2, H2O, and biogas - the product of biomass gasification), has been investigated. The modeling is based on the experimental data obtained in the reactor with a pulsed positive corona discharge. The problem of simulation of the cleaning process includes description of two stages. The first, fast stage is generation of primary active species during streamer propagation. The second, slow stage is the chain of chemical transformations triggered by these species. The input parameters for the modeling of the second stage are G-values for generation of primary active species, obtained under consideration of streamer dynamics. Simulation of the second stage of the removal process takes into account the processes of chemical kinetics and diffusion outside and inside of streamer traces during multi-pulsed treatment. Besides neutral active species, streamer discharges produce electrons and ions. Primary positive ions (N2+, CO+, CO2+, H2+, H2O+) in a chain of fast ion-molecule reactions transform into more stable positive ions. The ions recombine with electrons. Both ion-molecule reactions and electron-ion recombination process are additional (to dissociation of gas molecules by electron impact in the streamer head) sources of neutral active species. The relative contribution of these sources to the G-values for H, OH and O is rather large. In our modeling two approaches have been used. At the first approach the contribution of ion-molecule reactions is estimated approximately assuming that the dominating stable ion is N4+ (in pure N2 and its mixtures with H2) or CO2+ (in mixtures including CO2). Other way is the calculations with kinetic scheme including the molecular ions, aquated ions such as H3O(H2O)m+, NO2(H2O)-, NO2(H2O)+ and other. The comparison of results of two approaches is presented. Only full kinetic scheme allowed describing the

  10. H2O Southern Galactic Plane Survey (HOPS): Paper III - properties of dense molecular gas across the inner Milky Way

    Science.gov (United States)

    Longmore, S. N.; Walsh, A. J.; Purcell, C. R.; Burke, D. J.; Henshaw, J.; Walker, D.; Urquhart, J.; Barnes, A. T.; Whiting, M.; Burton, M. G.; Breen, S. L.; Britton, T.; Brooks, K. J.; Cunningham, M. R.; Green, J. A.; Harvey-Smith, L.; Hindson, L.; Hoare, M. G.; Indermuehle, B.; Jones, P. A.; Lo, N.; Lowe, V.; Moore, T. J. T.; Thompson, M. A.; Voronkov, M. A.

    2017-09-01

    The H2O Southern Galactic Plane Survey (HOPS) has mapped 100 deg2 of the Galactic plane for water masers and thermal molecular line emission using the 22 m Mopra telescope. We describe the automated spectral-line fitting pipelines used to determine the properties of emission detected in HOPS data cubes, and use these to derive the physical and kinematic properties of gas in the survey. A combination of the angular resolution, sensitivity, velocity resolution and high critical density of lines targeted make the HOPS data cubes ideally suited to finding precursor clouds to the most massive and dense stellar clusters in the Galaxy. We compile a list of the most massive HOPS ammonia regions and investigate whether any may be young massive cluster progenitor gas clouds. HOPS is also ideally suited to trace the flows of dense gas in the Galactic Centre. We find the kinematic structure of gas within the inner 500 pc of the Galaxy is consistent with recent predictions for the dynamical evolution of gas flows in the centre of the Milky Way. We confirm a recent finding that the dense gas in the inner 100 pc has an oscillatory kinematic structure with characteristic length-scale of 20 pc, and also identify similar oscillatory kinematic structure in the gas at radii larger than 100 pc. Finally, we make all of the above fits and the remaining HOPS data cubes across the 100 deg2 of the survey available to the community.

  11. Pulsed Discharge Characteristics of SF6/H2 and SF6/C2 H6 Mixtures and Their Effects on Output Laser%SF6/H2和SF6/C2 H6气体激光介质脉冲放电特性及其对输出激光的影响

    Institute of Scientific and Technical Information of China (English)

    易爱平; 唐影; 黄珂; 朱峰; 黄超; 马连英; 于力; 刘晶儒

    2016-01-01

    在未采取预电离措施的情况下,研究了纯SF6气体及SF6/H2和SF6/C2 H6两种混合气体激光介质脉冲放电特性。实验结果表明,无预电离时 SF6及其混合气体介质可以实现自引发体放电,气体介质体放电维持电压主要由 SF6含量决定,C2 H 6具有抑制电弧的作用,可以有效延长体放电维持时间。分析认为,SF6气体高折合场强E/p导致的放电通道电流密度受限和高电负度χa 引起的放电通道中负离子分解产生二次电子,是介质实现自引发体放电的重要机理。%Stable volume discharge of gas mixture is the foundation for discharge pumped gas laser.In this paper,the pulsed discharge characteristics of SF6 ,SF6/H2 mixture,and SF6/C2 H6 mixture are studied without pre-ionization.The experimental results show that the pulsed self-initiation volume discharge in SF6 mixture can be realized without pre-ionization, and the voltage of volume discharge depends on SF6 partial pressure.C2 H6 can suppress the development of arc,and extend the time of volume discharge,and obviously improve the vol-ume discharge of SF6 gas.The discharge mechanisms of SF6 and its mixture are discussed.

  12. Development and analysis of a new integrated power and cooling plant using LiBr–H2O mixture

    Indian Academy of Sciences (India)

    R Shankar; T Srinivas

    2014-12-01

    Cooling needs are increasing rapidly at hot climatic countries with increased global warming. The existed vapour compression refrigeration (VCR) system demands electricity for its operation which is more expensive. The concept of a newly proposed cooling cogeneration cycle has been developed by clubbing the power and cooling processes. It consists of characteristics of Rankine cycle and vapour absorption refrigeration (VAR) system and can be developed at hot climatic conditions with LiBr–water mixture as a working fluid. The results show that increase in heat source temperature is boosting power with a drop in cooling. The resulted cooling is seven times more than the power generation. The separator temperature has been recommended from 140 to 150°C to maximize the total output.

  13. Modeling of chemical processes in the low pressure capacitive RF discharges in a mixture of Ar/C2H2

    CERN Document Server

    Ariskin, D A; Alexandrov, A L; Bogaerts, A; Peeters, F M

    2008-01-01

    We study the properties of a capacitive 13.56 MHz discharge properties with a mixture of Ar/C2H2 taking into account the plasmochemistry and growth of heavy hydrocarbons. A hybrid model was developed to combine the kinetic description for electron motion and the fluid approach for negative and positive ions transport and plasmochemical processes. A significant change of plasma parameters related to injection of 5.8% portion of acetylene in argon was observed and analyzed. We found that the electronegativity of the mixture is about 30%. The densities of negatively and positively charged heavy hydrocarbons are sufficiently large to be precursors for the formation of nanoparticles in the discharge volume.

  14. Gas mixture studies for streamer operated Resistive Plate Chambers

    Science.gov (United States)

    Paoloni, A.; Longhin, A.; Mengucci, A.; Pupilli, F.; Ventura, M.

    2016-06-01

    Resistive Plate Chambers operated in streamer mode are interesting detectors in neutrino and astro-particle physics applications (like OPERA and ARGO experiments). Such experiments are typically characterized by large area apparatuses with no stringent requirements on detector aging and rate capabilities. In this paper, results of cosmic ray tests performed on a RPC prototype using different gas mixtures are presented, the principal aim being the optimization of the TetraFluoroPropene concentration in Argon-based mixtures. The introduction of TetraFluoroPropene, besides its low Global Warming Power, is helpful because it simplifies safety requirements allowing to remove also isobutane from the mixture. Results obtained with mixtures containing SF6, CF4, CO2, N2 and He are also shown, presented both in terms of detectors properties (efficiency, multiple-streamer probability and time resolution) and in terms of streamer characteristics.

  15. Non-isothermal differential adsorption kinetics for binary gas mixture

    Energy Technology Data Exchange (ETDEWEB)

    Sircar, S. (Air Products and Chemicals, Inc., Allentown, PA (United States))

    1994-06-01

    Analytical solutions are developed for non-isothermal adsorption kinetics of a binary gas mixture in a differential adsorption test (DAT). Linear driving force models are used to describe the adsorption kinetics of individual components. It is demonstrated that a very small change in the adsorbent temperature can introduce a substantial difference between isothermal and non-isothermal kinetic behaviors of the components of the mixture. The fractional uptake of a component of the mixture can exceed unity and go through a maximum value during the DAT due to the non-isothermal effects. An isothermal kinetic model for binary mixture adsorption using both straight and cross transport coefficients can also describe such uptake behavior, but the model parameters will be artificial due to the ignorance of adsorbent non-isothermality.

  16. 油气田中C02/H2S腐蚀与防护技术的研究进展%Research Progress on CO2/H2S Corrosion and Protection Technique in Oil and Gas Fields

    Institute of Scientific and Technical Information of China (English)

    耿春雷; 顾军; 徐永模; 翁端

    2011-01-01

    大多数油气田都会含有C0_2/H_2S等腐蚀性气体,而CO_2/H_2S腐蚀是油气田采集、运输、处理过程中主要的腐蚀介质.综述了CO_2/ H_2S腐蚀机理以及影响因素,并在此基础上介绍了防腐蚀涂层技术、缓蚀剂技术、过滤吸附技术以及新型牺牲阳极技术等国内外常用的防腐措施在防止C0_2/H_2S腐蚀中的应用,并指出各种新的防止CO_2/H_2S腐蚀的方法将会不断被提出并得到应用.%There are several corrosive gases in most oil and gas fields , such as CO2 and H2S. The corrosions of CO2 and H2S are the main corrosion in gathering, delivering and disposing. The corrosive mechanism and influencing factors of CO2 and H2S corrosions are described, based on which several anti-corrosion measures are introduced, such as the technology of coating, inhibitors, adsorption, sacrificial anode. It is also pointed out that many new measures will be invented and applied in protecting corrosions of CO2 and H2S in the oil and gas fields.

  17. CO2 capture from simulated fuel gas mixtures using semiclathrate hydrates formed by quaternary ammonium salts.

    Science.gov (United States)

    Park, Sungwon; Lee, Seungmin; Lee, Youngjun; Seo, Yongwon

    2013-07-02

    In order to investigate the feasibility of semiclathrate hydrate-based precombustion CO2 capture, thermodynamic, kinetic, and spectroscopic studies were undertaken on the semiclathrate hydrates formed from a fuel gas mixture of H2 (60%) + CO2 (40%) in the presence of quaternary ammonium salts (QASs) such as tetra-n-butylammonium bromide (TBAB) and fluoride (TBAF). The inclusion of QASs demonstrated significantly stabilized hydrate dissociation conditions. This effect was greater for TBAF than TBAB. However, due to the presence of dodecahedral cages that are partially filled with water molecules, TBAF showed a relatively lower gas uptake than TBAB. From the stability condition measurements and compositional analyses, it was found that with only one step of semiclathrate hydrate formation with the fuel gas mixture from the IGCC plants, 95% CO2 can be enriched in the semiclathrate hydrate phase at room temperature. The enclathration of both CO2 and H2 in the cages of the QAS semiclathrate hydrates and the structural transition that results from the inclusion of QASs were confirmed through Raman and (1)H NMR measurements. The experimental results obtained in this study provide the physicochemical background required for understanding selective partitioning and distributions of guest gases in the QAS semiclathrate hydrates and for investigating the feasibility of a semiclathrate hydrate-based precombustion CO2 capture process.

  18. Cooling of Dense Gas by H2O Line Emission and an Assessment of its Effects in Chondrule-Forming Shocks

    CERN Document Server

    Morris, M A; Ciesla, F J

    2008-01-01

    We consider gas at densities appropriate to protoplanetary disks and calculate its ability to cool due to line radiation emitted by H2O molecules within the gas. Our work follows that of Neufeld & Kaufman (1993; ApJ, 418, 263), expanding on their work in several key aspects, including use of a much expanded line database, an improved escape probability formulism, and the inclusion of dust grains, which can absorb line photons. Although the escape probabilities formally depend on a complicated combination of optical depth in the lines and in the dust grains, we show that the cooling rate including dust is well approximated by the dust-free cooling rate multiplied by a simple function of the dust optical depth. We apply the resultant cooling rate of a dust-gas mixture to the case of a solar nebula shock pertinent to the formation of chondrules, millimeter-sized melt droplets found in meteorites. Our aim is to assess whether line cooling can be neglected in chondrule-forming shocks or if it must be included....

  19. Phase separation in H2O:N2 mixture - molecular dynamics simulations using atomistic force fields

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, A; Gee, R; Bastea, S; Fried, L

    2006-09-25

    A class II atomistic force field with Lennard-Jones 6-9 nonbond interactions is used to investigate equations of state (EOS) for important high explosive detonation products N{sub 2} and H{sub 2}O in the temperature range 700-2500 K and pressure range 0.1-10 GPa. A standard 6th order parameter-mixing scheme is then employed to study a 2:1 (molar) H{sub 2}O:N{sub 2} mixture, to investigate in particular the possibility of phase-separation under detonation conditions. The simulations demonstrate several important results, including: (1) the accuracy of computed EOS for both N{sub 2} and H{sub 2}O over the entire range of temperature and pressure considered; (2) accurate mixing-demixing phase boundary as compared to experimental data; and (3) the departure of mixing free energy from that predicted by ideal mixing law. The results provide comparison and guidance to state-of-the-art chemical kinetic models.

  20. Low temperature H2S removal with 3-D structural mesoporous molecular sieves supported ZnO from gas stream.

    Science.gov (United States)

    Li, L; Sun, T H; Shu, C H; Zhang, H B

    2016-07-05

    A series of 3-dimensional (3-D) structural mesoporous silica materials, SBA-16, MCM-48 and KIT-6, was synthesized and supported with different ZnO loadings (10, 20, 30, and 40 wt%) by the incipient wetness method to evaluate the performances on H2S removal at room temperature. These materials were characterized by N2 adsorption, XRD, and TEM to investigate their textural properties. All the ZnO-loaded adsorbents exhibited the H2S removal capacity of bellow 0.1 ppmv. With the best ZnO loading percentage of 30 wt% on MCM-48 and KIT-6, 20 wt% on SBA-16 according to the results of breakthrough test, further increasing ZnO loading caused the decrease of the adsorption capacity due to the agglomeration of ZnO. Besides, the H2S adsorption capacities of the supports materials varied in the order of KIT-6>MCM-48>SBA-16, which was influenced primarily by their pore volume and pore size. With the largest pores in these 3-D arrangement materials, KIT-6 showed the best performance of supported material for ZnO, due to its retained superior physical properties as well as large pore diameter to allow faster gas-solid interaction and huge pore volume to disperse ZnO on the surface of it.

  1. Equilibrium water content measurements for acid gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, R.A.; Fitzpatrick, E.; Bernard, F.; Wan, H.H.; Lesage, K.L.; Davis, P.M.; Clark, P.D. [Alberta Sulphur Research Ltd., Calgary, AB (Canada)

    2009-07-01

    An accurate understanding of acid gas and water equilibrium is needed in order to design safe acid gas injection facilities. This paper described a joint industry project conducted to measure the water content of acid gas mixtures under moderate pressures and temperatures. The study has accumulated over 160 data points. Techniques used to obtain the measurements have included visual dew point determination for liquid acid gas and hydrates; the equilibration of samples in stirred autoclaves; basic static equilibration cells; and an isolated floating piston with a micro-sampler used to inject gaseous and liquid acid gas phases. As a result of the project, a high pressure micro-sampling technique has been developed to pressure limits of 1000 bar. 33 refs., 2 tabs., 10 figs.

  2. Powerful H2 Line Cooling in Stephan’s Quintet. II. Group-wide Gas and Shock Modeling of the Warm H2 and a Comparison with [C II] 157.7 μm Emission and Kinematics

    Science.gov (United States)

    Appleton, P. N.; Guillard, P.; Togi, A.; Alatalo, K.; Boulanger, F.; Cluver, M.; Pineau des Forêts, G.; Lisenfeld, U.; Ogle, P.; Xu, C. K.

    2017-02-01

    We map for the first time the two-dimensional H2 excitation of warm intergalactic gas in Stephan's Quintet on group-wide (50 × 35 kpc2) scales to quantify the temperature, mass, and warm H2 mass fraction as a function of position using Spitzer. Molecular gas temperatures are seen to rise (to T > 700 K) and the slope of the power-law density–temperature relation flattens along the main ridge of the filament, defining the region of maximum heating. We also performed MHD modeling of the excitation properties of the warm gas, to map the velocity structure and energy deposition rate of slow and fast molecular shocks. Slow magnetic shocks were required to explain the power radiated from the lowest-lying rotational states of H2, and strongly support the idea that energy cascades down to small scales and low velocities from the fast collision of NGC 7318b with group-wide gas. The highest levels of heating of the warm H2 are strongly correlated with the large-scale stirring of the medium as measured by [C ii] spectroscopy with Herschel. H2 is also seen associated with a separate bridge that extends toward the Seyfert nucleus in NGC 7319, from both Spitzer and CARMA CO observations. This opens up the possibility that both galaxy collisions and outflows from active galactic nuclei can turbulently heat gas on large scales in compact groups. The observations provide a laboratory for studying the effects of turbulent energy dissipation on group-wide scales, which may provide clues about the heating and cooling of gas at high z in early galaxy and protogalaxy formation.

  3. Gas adsorption and gas mixture separations using mixed-ligand MOF material

    Science.gov (United States)

    Hupp, Joseph T.; Mulfort, Karen L.; Snurr, Randall Q.; Bae, Youn-Sang

    2011-01-04

    A method of separating a mixture of carbon dioxiode and hydrocarbon gas using a mixed-ligand, metal-organic framework (MOF) material having metal ions coordinated to carboxylate ligands and pyridyl ligands.

  4. 炼厂含硫污水线H2S气体泄漏的数值模拟%Numerical Simulation of H2S Gas Leakage of a Sulfur-containing Waste Water Pipe in a Refinery

    Institute of Scientific and Technical Information of China (English)

    乔桥; 程光旭

    2014-01-01

    研究毒气的泄漏传播问题,对保证炼油企业的人员安全意义重大。本文根据国内某炼厂提供的真实地理信息建立三维几何模型,使用计算流体力学(CFD)的方法,并通过计算机群多节点并行计算对其厂区内含硫污水管道 H2S 气体的泄漏问题进行了数值模拟。研究了平面高度、风速及泄漏时间等因素对 H2S 浓度分布的影响,获得了气体传播的演化过程。结果表明:H2S 在泄漏源的下风方向呈带状分布;其含量随平面高度增加而减少,传播速度随风速增加而增大;泄漏确认及风向风速的实时监测对应急响应至关重要。%It is of great significance to guarantee the staff’s safety in a refinery by investigating the leakage and diffusion of toxic gas. According to the real geographic information provided by a refinery in China, a 3D geometrical model was established and H2S gas leakage of a sulfur-containing waste water pipe in the refinery was numerically simulated by computational fluid dynamics(CFD) method and multi-node parallel computing technology. The influences of factors such as altitude, wind speed and leakage time on the concentration distribution of H2S were studied, and the gas diffusion process was obtained. The results show that H2S gas presents a zonal distribution downwind from the leakage source. The content of H2S gas decreases with the increase of altitude. The diffusion velocity of H2S gas increases with the wind speed. Leakage conformation and the real-time supervision of wind direction and wind speed are of vital importance to the emergency response.

  5. Thermodynamic description of equilibria in mixed fluids (H 2O-non-polar gas) over a wide range of temperature (25-700°C) and pressure (1-5000 bars)

    Science.gov (United States)

    Akinfiev, Nikolai; Zotov, Alexander

    1999-07-01

    A new method for computing complicated equilibria in hydrothermal mixed fluids, H 2O-non-polar gas, is proposed. The computation algorithm is based on the electrostatic approach for the interaction between aqueous species and H 2O. The approach uses the SUPCRT92 database and the HKF format and may be considered as an application of the revised HKF model for mixed H 2O-non-polar gas fluids. Thermodynamic properties of dissolved gases at high temperatures and pressures are calculated using the Redlich-Kwong approach. Dielectric permittivity of the mixed solvent is estimated by the modified Kirkwood equation. The proposed approach is validated using available experimental data on the dissociation constants of H 2O and NaCl and the solubility of both covalent and ion crystals (SiO 2, AgCl, Ag 2SO 4, Ca(OH) 2, CaCO 3) in H 2O-non-polar component (dioxane, Ar, CO 2) mixtures. Predicted and experimental data are in close agreement over a wide range of P- T- xgas conditions (up to 500°C, 4 kbar and 0.25-0.3 mole fraction of non-polar gas). It is also shown how the computation method can be applied to estimate the Born parameters of aqueous species. The proposed approach enables not only examination of isolated reactions, but the study of equilibria of whole systems. Thus, it allows modelling of mixed natural fluids.

  6. Study of ionization losses in He-based gas mixtures

    CERN Document Server

    Borsato, E; Dal Corso, F; Morandin, M; Posocco, M; Stroili, R; Voci, C; Buccheri, A; Ferroni, F; Lacava, F; Lamanna, E; Mazzoni, M A; Morganti, S; Pastore, F C; Piredda, G; Pontecorvo, L

    1999-01-01

    Helium based gas mixtures are particularly interesting since they have a good tracking resolution because of the reduced multiple scattering. We have studied the differential energy loss dE/dx in several mixtures, He-isobutane and He-ethane. We present results from measurements performed with electrons, pions and protons in the momentum range between 1 and 5 GeV/c obtained in a prototype drift chamber with a 3 cm cell. The results show that helium performs well in measuring energy losses for charged particles.

  7. 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.

  8. Water Activities and Osmotic Coefficients of Aqueous Solutions of Five Alkyl-Aminium Sulfates and Their Mixtures with H2SO4 at 25 oC

    OpenAIRE

    Sauerwein, Meike; Clegg, Simon

    2015-01-01

    Alkylaminium sulfates are frequently detected in ambient aerosols, and are believed to be important in the nucleation of new particles in the atmosphere, despite their comparatively low gas phase concentrations. In this study water activities and osmotic coefficients have been measured, using a chilled mirror dew point technique, of aqueous mixtures of sulfuric acid and the following alkylaminium sulfates: methylaminium, ethylaminium, dimethylaminium, diethylaminium and trimethylaminium sulfa...

  9. Financial Risk Factor Analysis for Facility Gas Leakages of H2 and NG

    Directory of Open Access Journals (Sweden)

    In-Bok Lee

    2016-09-01

    Full Text Available Fuel cells may be the key to a more environmentally-friendly future because they emit low carbon dioxide per unit of energy supplied. However, little work has investigated the potential financial risks pertaining to fuel cell systems. Often used in the analysis of the safety of systems involving flammable or hazardous materials, risk factor analysis has recently been used to analyze the potential financial losses that may occur from industrial hazards. Therefore, this work undertakes a financial risk factor analysis to determine the costs of leakages of hydrogen and natural gas, which are used in fuel cell systems. Total leakage was calculated from an analysis of several leakage rates and modes. The impact of applying appropriate detection and prevention systems was also investigated. The findings were then used to analyze the consequences for various sections of the system and to calculate the overall cost based on facility outage or damage, and the cost of taking safety precautions. This provides a basis for comparison among proposed potential reactionary measures.

  10. Optimization of a gas sampling system for measuring eddy-covariance fluxes of H2O and CO2

    Directory of Open Access Journals (Sweden)

    S. Metzger

    2015-10-01

    Full Text Available Several initiatives are currently emerging to observe the exchange of energy and matter between the earth's surface and atmosphere standardized over larger space and time domains. For example, the National Ecological Observatory Network (NEON and the Integrated Carbon Observing System (ICOS will provide the ability of unbiased ecological inference across eco-climatic zones and decades by deploying highly scalable and robust instruments and data processing. In the construction of these observatories, enclosed infrared gas analysers are widely employed for eddy-covariance applications. While these sensors represent a substantial improvement compared to their open- and closed-path predecessors, remaining high-frequency attenuation varies with site properties, and requires correction. Here, we show that the gas sampling system substantially contributes to high-frequency attenuation, which can be minimized by careful design. From laboratory tests we determine the frequency at which signal attenuation reaches 50 % for individual parts of the gas sampling system. For different models of rain caps and particulate filters, this frequency falls into ranges of 2.5–16.5 Hz for CO2, 2.4–14.3 Hz for H2O, and 8.3–21.8 Hz for CO2, 1.4–19.9 Hz for H2O, respectively. A short and thin stainless steel intake tube was found to not limit frequency response, with 50 % attenuation occurring at frequencies well above 10 Hz for both H2O and CO2. From field tests we found that heating the intake tube and particulate filter continuously with 4 W was effective, and reduced the occurrence of problematic relative humidity levels (RH > 60 % by 50 % in the infrared gas analyser cell. No further improvement of H2O frequency response was found for heating in excess of 4 W. These laboratory and field tests were reconciled using resistor-capacitor theory, and NEON's final gas sampling system was developed on this basis. The design consists of the stainless steel intake tube

  11. Abatement of phenolic mixtures by catalytic wet oxidation enhanced by Fenton's pretreatment: effect of H2O2 dosage and temperature.

    Science.gov (United States)

    Santos, A; Yustos, P; Rodriguez, S; Simon, E; Garcia-Ochoa, F

    2007-07-31

    Catalytic wet oxidation (CWO) of a phenolic mixture containing phenol, o-cresol and p-cresol (500mg/L on each pollutant) has been carried out using a commercial activated carbon (AC) as catalyst, placed in a continuous three-phase reactor. Total pressure was 16 bar and temperature was 127 degrees C. Pollutant conversion, mineralization, intermediate distribution, and toxicity were measured at the reactor outlet. Under these conditions no detoxification of the inlet effluent was found even at the highest catalyst weight (W) to liquid flow rate (Q(L)) ratio used. On the other hand, some Fenton Runs (FR) have been carried out in a batch way using the same phenolic aqueous mixture previously cited. The concentration of Fe(2+) was set to 10mg/L. The influence of the H(2)O(2) amount (between 10 and 100% of the stoichiometric dose) and temperature (30, 50, and 70 degrees C) on phenols conversion, mineralization, and detoxification have been analyzed. Phenols conversion was near unity at low hydrogen peroxide dosage but mineralization and detoxification achieved an asymptotic value at each temperature conditions. The integration of Fenton reagent as pretreatment of the CWO process remarkably improves the efficiency of the CWO reactor and allows to obtain detoxified effluents at mild temperature conditions and relatively low W/Q(L) values. For a given phenolic mixture a temperature range of 30-50 degrees C in the Fenton pretreatment with a H(2)O(2) dosage between 20 and 40% of the stoichiometric amount required can be proposed.

  12. 油气管道CO2/H2 S腐蚀及防护技术研究进展%Research Progress of CO2/H2 S Corrosion in Oil and Gas Pipelines and the Protection Techniques

    Institute of Scientific and Technical Information of China (English)

    王丹; 袁世娇; 吴小卫; 谢飞; 赵启慧; 杨帆; 程贵鑫

    2016-01-01

    CO2和H2 S是油气管道中主要的腐蚀介质,两者往往同时存在于原油和天然气之中,是造成油气输送管道内腐蚀发生的主要原因之一,甚至会导致管道失效、穿孔、泄漏、开裂等现象,严重威胁了管网的安全运行及正常生产。因此CO2和H2 S引起的管道腐蚀问题,已成为当前研究的热点问题。针对油气管道日益严重的CO2和H2 S腐蚀问题,综述了CO2单独存在、H2 S单独存在以及CO2和H2 S共同存在三种体系中油气管道的腐蚀过程,得出了在这三种腐蚀体系下油气管道出现的主要腐蚀行为规律以及腐蚀机理。阐述了CO2和H2 S共同存在体系下,缓蚀剂、耐蚀性管材、电化学防腐技术、管道内涂层技术等先进的油气管道腐蚀防护技术,并剖析了这些防护措施各自的特点及在实际工程使用中的优势和局限性。最后,展望了CO2和H2 S共存体系的进一步研究方向以及更经济、更有效的防腐措施发展前景。%ABSTRACT:CO2 and H2 S are the major corrosion media in oil and gas pipeline, often existing in both crude oil and natural gas. Their presence is one of the main causes for internal corrosion in oil and gas pipelines, and even leads to pipeline failure, perfora-tions, leaks and cracks. It′s a serious threat to the safe operation of the pipeline network and normal production. So pipeline corro-sion problems caused by CO2 and H2 S have become a hot issue of current research. For the growing oil and gas pipeline corrosion problems caused by CO2 and H2 S, the corrosion behaviors of oil and gas pipelines in CO2 alone, H2 S alone and the co-existence of CO2 and H2 S system were systematically compared in this paper. The law and mechanism of pipeline corrosion behavior in these three corrosion systems were obtained. And the protection techniques against oil and gas pipeline corrosion were listed, such as cor-rosion inhibitors, corrosion resistant pipes

  13. Carbothermal Reduction of Quartz in Methane-Hydrogen-Argon Gas Mixture

    Science.gov (United States)

    Li, Xiang; Zhang, Guangqing; Tang, Kai; Ostrovski, Oleg; Tronstad, Ragnar

    2015-10-01

    Synthesis of silicon carbide (SiC) by carbothermal reduction of quartz in a CH4-H2-Ar gas mixture was investigated in a laboratory fixed-bed reactor in the temperature range of 1573 K to 1823 K (1300 °C to 1550 °C). The reduction process was monitored by an infrared gas analyser, and the reduction products were characterized by LECO, XRD, and SEM. A mixture of quartz-graphite powders with C/SiO2 molar ratio of 2 was pressed into pellets and used for reduction experiments. The reduction was completed within 2 hours under the conditions of temperature at or above 1773 K (1500 °C), methane content of 0.5 to 2 vol pct, and hydrogen content ≥70 vol pct. Methane partially substituted carbon as a reductant in the SiC synthesis and enhanced the reduction kinetics significantly. An increase in the methane content above 2 vol pct caused excessive carbon deposition which had a detrimental effect on the reaction rate. Hydrogen content in the gas mixture above 70 vol pct effectively suppressed the cracking of methane.

  14. Study on the recovery of hydrogen from refinery (hydrogen+methane) gas mixtures using hydrate technology

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A novel technique for separating hydrogen from (H2 + CH4) gas mixtures through hydrate formation/dissociation was proposed. In this work, a systematic experimental study was performed on the separation of hydrogen from (H2 + CH4) feed mixtures with various hydrogen contents (mole fraction x = 40%-90%). The experimental results showed that the hydrogen content could be enriched to as high as ~94% for various feed mixtures using the proposed hydrate technology under a temperature slightly above 0℃ and a pressure below 5.0 MPa. With the addition of a small amount of suitable additives, the rate of hydrate formation could be increased significantly. Anti-agglomeration was used to disperse hydrate particles into the condensate phase. Instead of preventing hydrate growth (as in the kinetic inhibitor tests), hydrates were allowed to form, but only as small dispersed particles. Anti-agglomeration could keep hydrate particles suspended in a range of condensate types at 1℃ and 5 MPa in the water-in-oil emulsion.

  15. Study on the recovery of hydrogen from refinery (hydrogen + methane) gas mixtures using hydrate technology

    Institute of Scientific and Technical Information of China (English)

    WANG XiuLin; CHEN GuangJin; YANG LanYing; ZHANG LinWei

    2008-01-01

    A novel technique for separating hydrogen from (H2 + CH4) gas mixtures through hydrate forma-tion/dissociation was proposed.In this work, a systematic experimental study was performed on the separation of hydrogen from (H2+CH4) feed mixtures with various hydrogen contents (mole fraction x =40%-90%).The experimental results showed that the hydrogen content could be enriched to as high as~94% for various feed mixtures using the proposed hydrate technology under a temperature slightly above 0℃ and a pressure below 5.0 MPa.With the addition of a small amount of suitable additives, the rate of hydrate formation could be increased significantly.Anti-agglomeration was used to disperse hydrate particles into the condensate phase.Instead of preventing hydrate growth (as in the kinetic inhibitor tests), hydrates were allowed to form, but only as small dispersed particles.Anti-agglomera-tion could keep hydrate particles suspended in a range of condensate types at 1℃ and 5 MPa in the water-in-oil emulsion.

  16. Lorentz Angle Measurement for CO2/Isobutane Gas Mixtures

    CERN Document Server

    Hoshina, K; Khalatyan, N S; Nitoh, O; Okuno, H; Kato, Y; Kobayashi, M; Kurihara, Y; Kuroiwa, H; Nakamura, Y; Sakieda, K; Suzuki, Y; Watanabe, T

    2002-01-01

    We have developed a Lorentz angle measurement system for cool gas mixtures in the course of our R&D for a proposed JLC central drift chamber (JLC-CDC). The measurement system is characterized by the use of two laser beams to produce primary electrons and flash ADCs to read their signals simultaneously. With this new system, we have measured Lorentz angles for CO2/isobutane gas mixtures with different proportions (95:5, 90:10, and 85:15), varying drift field from 0.6 to 2.0 kV/cm and magnetic field up to 1.5 T. The results of the measurement are in good agreement with GARFIELD/MAGBOLTZ simulations.

  17. Systematic study of gas mixtures for timing RPCs

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, L., E-mail: luisalberto@coimbra.lip.pt [LIP-Laboratorio de Instrumentacao e Fisica Experimental de Particulas, 3004-516 Coimbra (Portugal); Fonte, P. [LIP-Laboratorio de Instrumentacao e Fisica Experimental de Particulas, 3004-516 Coimbra (Portugal); Intituto Superior de Engenharia de Coimbra, 3030-199 Coimbra (Portugal); Mangiarotti, A. [LIP-Laboratorio de Instrumentacao e Fisica Experimental de Particulas, 3004-516 Coimbra (Portugal)

    2012-01-01

    RPC timing properties are mainly determined by the maximum ionization rate that can be sustained while keeping the streamer fraction at modest values. The last characteristic, resilience to streamers, cannot be fully calculated, calling for an experimental approach. In this work we systematically study the influence of a range of gas mixtures on the performance (background counting rate, efficiency, time resolution and charge spectrum) of timing RPCs, using cosmic rays as ionizing particles.

  18. Dopant-assisted negative photoionization Ion mobility spectrometry coupled with on-line cooling inlet for real-time monitoring H2S concentration in sewer gas.

    Science.gov (United States)

    Peng, Liying; Jiang, Dandan; Wang, Zhenxin; Hua, Lei; Li, Haiyang

    2016-06-01

    Malodorous hydrogen sulfide (H2S) gas often exists in the sewer system and associates with the problems of releasing the dangerous odor to the atmosphere and causing sewer pipe to be corroded. A simple method is in demand for real-time measuring H2S level in the sewer gas. In this paper, an innovated method based on dopant-assisted negative photoionization ion mobility spectrometry (DANP-IMS) with on-line semiconductor cooling inlet was put forward and successfully applied for the real-time measurement of H2S in sewer gas. The influence of moisture was effectively reduced via an on-line cooling method and a non-equilibrium dilution with drift gas. The limits of quantitation for the H2S in ≥60% relative humidity air could be obtained at ≤79.0ng L(-1) with linear ranges of 129-2064ng L(-1). The H2S concentration in a sewer manhole was successfully determined while its product ions were identified by an ion-mobility time-of-fight mass spectrometry. Finally, the correlation between sewer H2S concentration and the daily routines and habits of residents was investigated through hourly or real-time monitoring the variation of sewer H2S in manholes, indicating the power of this DANP-IMS method in assessing the H2S concentration in sewer system. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Kinetics of NO formation and decay in nanosecond pulse discharges in Air, H2-Air, and C2H4-Air mixtures

    Science.gov (United States)

    Burnette, David; Shkurenkov, Ivan; Adamovich, Igor V.; Lempert, Walter R.

    2016-04-01

    Time-resolved, absolute NO and N atom number densities are measured by NO Laser Induced Fluorescence (LIF) and N Two-Photon Absorption LIF in a diffuse plasma filament, nanosecond pulse discharge in dry air, hydrogen-air, and ethylene-air mixtures at 40 Torr, over a wide range of equivalence ratios. The results are compared with kinetic modeling calculations incorporating pulsed discharge dynamics, kinetics of vibrationally and electronically excited states of nitrogen, plasma chemical reactions, and radial transport. The results show that in air afterglow, NO decay occurs primarily by the reaction with N atoms, NO  +  N  →  N2  +  O. In the presence of hydrogen, this reaction is mitigated by reaction of N atoms with OH, N  +  OH  →  NO  +  H, resulting in significant reduction of N atom number density in the afterglow, additional NO production, and considerably higher NO number densities. In fuel-lean ethylene-air mixtures, a similar trend (i.e. N atom concentration reduction and NO number density increase) is observed, although [NO] increase on ms time scale is not as pronounced as in H2-air mixtures. In near-stoichiometric and fuel-lean ethylene-air mixtures, when N atom number density was below detection limit, NO concentration was measured to be lower than in air plasma. These results suggest that NO kinetics in hydrocarbon-air plasmas is more complex compared to air and hydrogen-air plasmas, additional NO reaction pathways may well be possible, and their analysis requires further kinetic modeling calculations.

  20. A fast response & recovery H2S gas sensor based on α-Fe2O3 nanoparticles with ppb level detection limit.

    Science.gov (United States)

    Li, Zhijie; Huang, Yanwu; Zhang, Shouchao; Chen, Weimei; Kuang, Zhong; Ao, Dongyi; Liu, Wei; Fu, Yongqing

    2015-12-30

    H2S gas sensor based on α-Fe2O3 nanoparticles was fabricated by post-thermal annealing of Fe3O4 precursor which was synthesized using a facile hydrothermal route. The characteristic techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were adopted to characterize the chemical composition and microstructure of the obtained samples. Gas-sensing performance of the sensor was investigated at different operation temperatures from 100°C to 400°C. Results showed that the sensor exhibited the best sensitivity, reproducibility and long-term stability for detecting H2S gas at an operating temperature of 300°C. The detection limit towards H2S gas was 0.05 ppm, and the response time and recovery time was 30s and 5s, respectively. In addition, sensing mechanism of the sensor towards H2S was discussed.

  1. Understanding the response behavior of potentiometric gas sensors for non-equilibrium gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Garzon, F. H. (Fernando H.); Mukundan, R. (Rangachary); Brosha, E. L. (Eric L.)

    2002-01-01

    Many applications of gas sensors require concentration measurements of reactive gases in mixtures that are out of thermodynamic equilibrium. These applications include: hydrogen and hydrocarbon fuel gas sensors operating in ambient air for explosion hazard detection, carbon monoxide detection in ambient air for health protection, combustion efficiency sensors for stoichiometry control, and nitric oxide sensors for air pollution monitoring. Many potentiometric and amperometric electrochemical sensor technologies have been developed for these applications. A class of the potentiometric sensors developed for gas mixtures are the non-Nerstian sensors. This presentation defines a categorization and theoretical analysis of three distinct electrochemical processes that can produce a non-Nernstian sensor response.

  2. Porous iron molybdate nanorods: in situ diffusion synthesis and low-temperature H2S gas sensing.

    Science.gov (United States)

    Chen, Yu-Jin; Gao, Xin-Ming; Di, Xin-Peng; Ouyang, Qiu-Yun; Gao, Peng; Qi, Li-Hong; Li, Chun-Yan; Zhu, Chun-Ling

    2013-04-24

    In the paper, we developed an in situ diffusion growth method to fabricate porous Fe2(MoO4)3 nanorods. The average diameter and the length of the porous nanorods were 200 nm and 1.2-4 μm, respectively. Moreover, many micropores existed along axial direction of the Fe2(MoO4)3 nanorods. In terms of nitrogen adsorption-desorption isotherms, calculated pore size was in the range of 4-115 nm, agreeing well with the transmission electron microscope observations. Because of the uniquely porous characteristics and catalytic ability at low temperatures, the porous Fe2(MoO4)3 nanorods exhibited very good H2S sensing properties, including high sensitivity at a low working temperature (80 °C), relatively fast response and recovery times, good selectivity, and long-term stability. Thus, the porous Fe2(MoO4)3 nanorods are very promising for the fabrication of high-performance H2S gas sensors. Furthermore, the strategy presented here could be expended as a general method to synthesize other hollow/porous-type transition metal molybdate nanostructures by rational designation in nanoscale.

  3. Sensing Characteristics of Flame-Spray-Made Pt/ZnO Thick Films as H2 Gas Sensor

    Directory of Open Access Journals (Sweden)

    Nittaya Tamaekong

    2009-08-01

    Full Text Available Hydrogen sensing of thick films of nanoparticles of pristine, 0.2, 1.0 and 2.0 atomic percentage of Pt concentration doped ZnO were investigated. ZnO nanoparticles doped with 0.2–2.0 at.% Pt were successfully produced in a single step by flame spray pyrolysis (FSP technique using zinc naphthenate and platinum(II acetylacetonate as precursors dissolved in xylene. The particle properties were analyzed by XRD, BET, SEM and TEM. Under the 5/5 (precursor/oxygen flame condition, ZnO nanoparticles and nanorods were observed. The crystallite sizes of ZnO spheroidal and hexagonal particles were found to be ranging from 5 to 20 nm while ZnO nanorods were seen to be 5–20 nm wide and 20–40 nm long. ZnO nanoparticles paste composed of ethyl cellulose and terpineol as binder and solvent respectively was coated on Al2O3 substrate interdigitated with gold electrodes to form thin films by spin coating technique. The thin film morphology was analyzed by SEM technique. The gas sensing properties toward hydrogen (H2 was found that the 0.2 at.% Pt/ZnO sensing film showed an optimum H2 sensitivity of ~164 at hydrogen concentration in air of 1 volume% at 300 °C and a low hydrogen detection limit of 50 ppm at 300 °C operating temperature.

  4. Implementation of a quantum cascade laser-based gas sensor prototype for sub-ppmv H2S measurements in a petrochemical process gas stream.

    Science.gov (United States)

    Moser, Harald; Pölz, Walter; Waclawek, Johannes Paul; Ofner, Johannes; Lendl, Bernhard

    2017-01-01

    The implementation of a sensitive and selective as well as industrial fit gas sensor prototype based on wavelength modulation spectroscopy with second harmonic detection (2f-WMS) employing an 8-μm continuous-wave distributed feedback quantum cascade laser (CW-DFB-QCL) for monitoring hydrogen sulfide (H2S) at sub-ppm levels is reported. Regarding the applicability for analytical and industrial process purposes aimed at petrochemical environments, a synthetic methane (CH4) matrix of up to 1000 ppmv together with a varying H2S content was chosen as the model environment for the laboratory-based performance evaluation performed at TU Wien. A noise-equivalent absorption sensitivity (NEAS) for H2S targeting the absorption line at 1247.2 cm(-1) was found to be 8.419 × 10(-10) cm(-1) Hz(-1/2), and a limit of detection (LOD) of 150 ppbv H2S could be achieved. The sensor prototype was then deployed for on-site measurements at the petrochemical research hydrogenation platform of the industrial partner OMV AG. In order to meet the company's on-site safety regulations, the H2S sensor platform was installed in an industry rack and equipped with the required safety infrastructure for protected operation in hazardous and explosive environments. The work reports the suitability of the sensor prototype for simultaneous monitoring of H2S and CH4 content in the process streams of a research hydrodesulfurization (HDS) unit. Concentration readings were obtained every 15 s and revealed process dynamics not observed previously.

  5. Composite-fermionization of the mixture composed of Tonks gas and Fermi gas

    Institute of Scientific and Technical Information of China (English)

    Hao Ya-Jiang

    2011-01-01

    This paper investigates the ground-state properties of the mixture composed of the strongly interacting TonksGirardeau gas and spin polarized Fermi gas confined in one-dimensional harmonic traps, where the interaction between the Bose atoms and Fermi atoms is tunable. With a generalized Bose-Fermi transformation the mixture is mapped into a two-component Fermi gas. The homogeneous Fermi gas is exactly solvable by the Bethe-ansatz method and the ground state energy density can be obtained. Combining the ground-state energy function of the homogeneous system with local density approximation it obtains the ground-state density distributions of inhomogeneous mixture. It is shown that with the increase in boson-fermion interaction, the system exhibits composite-fermionization crossover.

  6. Numerical modeling of gas mixing and bio-chemical transformations during underground hydrogen storage within the project H2STORE

    Science.gov (United States)

    Hagemann, B.; Feldmann, F.; Panfilov, M.; Ganzer, L.

    2015-12-01

    The change from fossil to renewable energy sources is demanding an increasing amount of storage capacities for electrical energy. A promising technological solution is the storage of hydrogen in the subsurface. Hydrogen can be produced by electrolysis using excessive electrical energy and subsequently converted back into electricity by fuel cells or engine generators. The development of this technology starts with adding small amounts of hydrogen to the high pressure natural gas grid and continues with the creation of pure underground hydrogen storages. The feasibility of hydrogen storage in depleted gas reservoirs is investigated in the lighthouse project H2STORE financed by the German Ministry for Education and Research. The joint research project has project members from the University of Jena, the Clausthal University of Technology, the GFZ Potsdam and the French National Center for Scientic Research in Nancy. The six sub projects are based on laboratory experiments, numerical simulations and analytical work which cover the investigation of mineralogical, geochemical, physio-chemical, sedimentological, microbiological and gas mixing processes in reservoir and cap rocks. The focus in this presentation is on the numerical modeling of underground hydrogen storage. A mathematical model was developed which describes the involved coupled hydrodynamic and microbiological effects. Thereby, the bio-chemical reaction rates depend on the kinetics of microbial growth which is induced by the injection of hydrogen. The model has been numerically implemented on the basis of the open source code DuMuX. A field case study based on a real German gas reservoir was performed to investigate the mixing of hydrogen with residual gases and to discover the consequences of bio-chemical reactions.

  7. Water Deuteration and Ortho-to-Para Nuclear Spin Ratio of H2 in Molecular Clouds Formed via Accumulation of HI Gas

    CERN Document Server

    Furuya, K; Hincelin, U; Hassel, G E; Bergin, E A; Vasyunin, A I; Herbst, Eric

    2015-01-01

    We investigate the water deuteration ratio and ortho-to-para nuclear spin ratio of H2 (OPR(H2)) during the formation and early evolution of a molecular cloud, following the scenario that accretion flows sweep and accumulate HI gas to form molecular clouds. We follow the physical evolution of post-shock materials using a one-dimensional shock model, with post-processing gas-ice chemistry simulations. This approach allows us to study the evolution of the OPR(H2) and water deuteration ratio without an arbitrary assumption concerning the initial molecular abundances, including the initial OPR(H2). When the conversion of hydrogen into H2 is almost complete, the OPR(H2) is already much smaller than the statistical value of three due to the spin conversion in the gas phase. As the gas accumulates, the OPR(H2) decreases in a non-equilibrium manner. We find that water ice can be deuterium-poor at the end of its main formation stage in the cloud, compared to water vapor observed in the vicinity of low-mass protostars w...

  8. 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.

  9. Experimental research on influencing factors of wet removal of NO from coal-fired flue gas by UV/H2O2 advanced oxidation process

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Wet removal of NO from coal-fired flue gas by UV/H2O2 Advanced Oxidation Process (AOP) were investigated in a self-designed UV-bubble reactor. Several main influencing factors (UV intensity, H2O2 initial concentration, initial pH value, solution temperature, NO initial concentration, liquid-gas ratio and O2 percentage content) on the NO removal efficiency were studied. The results showed that UV intensity, H2O2 initial concentration, NO initial concentration and liquid-gas ratio are the main influencing factors. In the best conditions, the highest NO removal efficiency by UV/H2O2 advanced oxidation process could reach 82.9%. Based on the experimental study, the influencing mechanism of the relevant influencing factors were discussed in depth.

  10. Validation of a novel Multi-Gas sensor for volcanic HCl alongside H2S and SO2 at Mt. Etna

    Science.gov (United States)

    Roberts, T. J.; Lurton, T.; Giudice, G.; Liuzzo, M.; Aiuppa, A.; Coltelli, M.; Vignelles, D.; Salerno, G.; Couté, B.; Chartier, M.; Baron, R.; Saffell, J. R.; Scaillet, B.

    2017-05-01

    Volcanic gas emission measurements inform predictions of hazard and atmospheric impacts. For these measurements, Multi-Gas sensors provide low-cost in situ monitoring of gas composition but to date have lacked the ability to detect halogens. Here, two Multi-Gas instruments characterized passive outgassing emissions from Mt. Etna's (Italy) three summit craters, Voragine (VOR), North-east Crater (NEC) and Bocca Nuova (BN) on 2 October 2013. Signal processing (Sensor Response Model, SRM) approaches are used to analyse H2S/SO2 and HCl/SO2 ratios. A new ability to monitor volcanic HCl using miniature electrochemical sensors is here demonstrated. A "direct-exposure" Multi-Gas instrument contained SO2, H2S and HCl sensors, whose sensitivities, cross-sensitivities and response times were characterized by laboratory calibration. SRM analysis of the field data yields H2S/SO2 and HCl/SO2 molar ratios, finding H2S/SO2 = 0.02 (0.01-0.03), with distinct HCl/SO2 for the VOR, NEC and BN crater emissions of 0.41 (0.38-0.43), 0.58 (0.54-0.60) and 0.20 (0.17-0.33). A second Multi-Gas instrument provided CO2/SO2 and H2O/SO2 and enabled cross-comparison of SO2. The Multi-Gas-measured SO2-HCl-H2S-CO2-H2O compositions provide insights into volcanic outgassing. H2S/SO2 ratios indicate gas equilibration at slightly below magmatic temperatures, assuming that the magmatic redox state is preserved. Low SO2/HCl alongside low CO2/SO2 indicates a partially outgassed magma source. We highlight the potential for low-cost HCl sensing of H2S-poor HCl-rich volcanic emissions elsewhere. Further tests are needed for H2S-rich plumes and for long-term monitoring. Our study brings two new advances to volcano hazard monitoring: real-time in situ measurement of HCl and improved Multi-Gas SRM measurements of gas ratios.

  11. Thermodynamic properties of acid gases in mixture with natural gas and water

    NARCIS (Netherlands)

    Tang, X.

    2011-01-01

    The reliable removal of acid gas components, such as carbon dioxide (CO2) and hydrogen sulfide (H2S) from natural gas is an important technical challenge. Crude oil and hydrocarbon gas streams may contain high levels of CO2 and/or H2S as contaminants. It is desirable to prevent any contaminant to re

  12. Multiphase flow of gas-liquid and gas coal slurry mixtures in vertical tubes

    Energy Technology Data Exchange (ETDEWEB)

    Javdani, K; Schwalbe, S; Fishcher, J

    1977-01-01

    This research was done as a support study for the SYNTHOIL process and other coal liquefaction processes being developed to produce clean liquid fuels from coal. The objective of this work is to obtain experimental data on flow characteristics for upward flow of gas-liquid-solid mixtures in vertical tubes simulating conditions in the SYNTHOIL process. Study of the transport phenomena of multiphase mixtures is of importance to many chemical engineering operations in general and to some other coal conversion processes in particular. A brief review of the application of this work to existing processes is presented. The first part of the program was devoted to the study of the flow characteristics of two-phase gas--liquid systems, and the second was devoted to the flow characteristics of gas--slurry mixtures.

  13. Testing of hydrotalcite based sorbents for CO2 and H2S capture for use in sorption enhanced water gas shift

    Energy Technology Data Exchange (ETDEWEB)

    Van Dijk, H.A.J.; Walspurger, S.; Cobden, P.D.; Van den Brink, R.W. [ECN Hydrogen and Clean Fossil Fuels, Petten (Netherlands)

    2011-03-15

    The feasibility of the sorption enhanced water gas shift (SEWGS) process under sour conditions is shown. The sour-SEWGS process constitutes a second generation pre-combustion carbon capture technology for the application in an IGCC. As a first critical step, the suitability of a K2CO3 promoted hydrotalcite-based CO2 sorbent is demonstrated by means of adsorption and regeneration experiments in the presence of 2000 ppm H2S. In multiple cycle experiments at 400C and 5 bar, the sorbent displays reversible co-adsorption of CO2 and H2S. The CO2 sorption capacity is not significantly affected compared to sulphur-free conditions. A mechanistic model assuming two different sites for H2S interaction explains qualitatively the interactions of CO2 and H2S with the sorbent. On the type A sites, CO2 and H2S display competitive sorption where CO2 is favoured. The type B sites only allow H2S uptake and may involve the formation of metal sulphides. This material behaviour means that the sour-SEWGS process likely eliminates CO2 and H2S simultaneously from the syngas and that an almost CO2 and H2S-free H2 stream and a CO2 + H2S stream can be produced.

  14. Operation of gas electron multiplier (GEM) with propane gas at low pressure and comparison with tissue-equivalent gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    De Nardo, L., E-mail: laura.denardo@unipd.it [University of Padova, Physics and Astronomy Department and PD-INFN, via Marzolo 8, I-35131 Padova (Italy); Farahmand, M., E-mail: majid.farahmand@rivm.nl [Centre for Environmental Safety and Security, National Institute for Public Health and the Environment (RIVM), PO Box 1, NL-3720 BA Bilthoven (Netherlands)

    2016-05-21

    A Tissue-Equivalent Proportional Counter (TEPC), based on a single GEM foil of standard geometry, has been tested with pure propane gas at low pressure, in order to simulate a tissue site of about 1 µm equivalent size. In this work, the performance of GEM with propane gas at a pressure of 21 and 28 kPa will be presented. The effective gas gain was measured in various conditions using a {sup 244}Cm alpha source. The dependence of effective gain on the electric field strength along the GEM channel and in the drift and induction region was investigated. A maximum effective gain of about 5×10{sup 3} has been reached. Results obtained in pure propane gas are compared with gas gain measurements in gas mixtures commonly employed in microdosimetry, that is propane and methane based Tissue-Equivalent gas mixtures.

  15. Polyimide hollow fiber membranes for CO2 separation from wet gas mixtures

    Directory of Open Access Journals (Sweden)

    F. Falbo

    2014-12-01

    Full Text Available Matrimid®5218 hollow fiber membranes were prepared using the dry-wet spinning process. The transport properties were measured with pure gases (H2, CO2, N2, CH4 and O2 and with a mixture (30% CO2 and 70% N2 in dry and wet conditions at 25 ºC, 50 ºC, 60 ºC and 75 ºC and up to 600 kPa. Interesting values of single gas selectivity up to 60 ºC (between 31 and 28 for CO2/N2 and between 33 and 30 for CO2/CH4 in dry condition were obtained. The separation factor measured for the mixture was 20% lower compared to the single gas selectivity, in the whole temperature range analyzed. In saturation conditions the data showed that water influences the performance of the membranes, inducing a reduction of the permeance of all gases. Moreover, the presence of water caused a decrease of single gas selectivity and separation factor, although not so significant, highlighting the very high water resistance of hollow fiber membrane modules.

  16. Chemical Discrimination in Turbulent Gas Mixtures with MOX Sensors Validated by Gas Chromatography-Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Jordi Fonollosa

    2014-10-01

    Full Text Available Chemical detection systems based on chemo-resistive sensors usually include a gas chamber to control the sample air flow and to minimize turbulence. However, such a kind of experimental setup does not reproduce the gas concentration fluctuations observed in natural environments and destroys the spatio-temporal information contained in gas plumes. Aiming at reproducing more realistic environments, we utilize a wind tunnel with two independent gas sources that get naturally mixed along a turbulent flow. For the first time, chemo-resistive gas sensors are exposed to dynamic gas mixtures generated with several concentration levels at the sources. Moreover, the ground truth of gas concentrations at the sensor location was estimated by means of gas chromatography-mass spectrometry. We used a support vector machine as a tool to show that chemo-resistive transduction can be utilized to reliably identify chemical components in dynamic turbulent mixtures, as long as sufficient gas concentration coverage is used. We show that in open sampling systems, training the classifiers only on high concentrations of gases produces less effective classification and that it is important to calibrate the classification method with data at low gas concentrations to achieve optimal performance.

  17. Chemical discrimination in turbulent gas mixtures with MOX sensors validated by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Fonollosa, Jordi; Rodríguez-Luján, Irene; Trincavelli, Marco; Vergara, Alexander; Huerta, Ramón

    2014-10-16

    Chemical detection systems based on chemo-resistive sensors usually include a gas chamber to control the sample air flow and to minimize turbulence. However, such a kind of experimental setup does not reproduce the gas concentration fluctuations observed in natural environments and destroys the spatio-temporal information contained in gas plumes. Aiming at reproducing more realistic environments, we utilize a wind tunnel with two independent gas sources that get naturally mixed along a turbulent flow. For the first time, chemo-resistive gas sensors are exposed to dynamic gas mixtures generated with several concentration levels at the sources. Moreover, the ground truth of gas concentrations at the sensor location was estimated by means of gas chromatography-mass spectrometry. We used a support vector machine as a tool to show that chemo-resistive transduction can be utilized to reliably identify chemical components in dynamic turbulent mixtures, as long as sufficient gas concentration coverage is used. We show that in open sampling systems, training the classifiers only on high concentrations of gases produces less effective classification and that it is important to calibrate the classification method with data at low gas concentrations to achieve optimal performance.

  18. High selectivity of a CuO modified hollow SnO2 nanofiber gas sensor to H2S at low temperature

    Science.gov (United States)

    Yang, Jiejie; Gao, Chaojun; Yang, Hui; Wang, Xinchang; Jia, Jianfeng

    2017-08-01

    CuO modified hollow SnO2 nanofibers with large specific surface area were successfully synthesized via a simple two-step process, using the electrospinning method and hydrothermal technique. Gas-sensing experiments on hierarchically CuO modified SnO2 hollow nanofibers displayed higher sensitivity and selectivity to H2S gas at lower operating temperatures compared with unmodified hollow SnO2 nanofibers. At the optimal operating temperature of 125 °C, the highest response value to 10 ppm H2S gas reached 410. Response time decreased when the concentration of H2S increased. It is almost no response to other gases when the operating temperature falls below 200 °C. The specific interaction between H2S gas and the CuO nanoparticles, as well as the amplifier effect on the gas response by the p-n junctions, strongly enhances the selectivity to H2S gas at a lower operating temperature.

  19. Hydrogenogenic CO Conversion in a Moderately Thermophilic (55 C) Sulfate-Fed Gas Lift Reactor: Competition for CO-Derived H2

    NARCIS (Netherlands)

    Sipma, J.; Lettinga, G.; Stams, A.J.M.; Lens, P.N.L.

    2006-01-01

    Thermophilic (55 °C) sulfate reduction in a gas lift reactor fed with CO gas as the sole electron donor was investigated. The reactor was inoculated with mesophilic granular sludge with a high activity of CO conversion to hydrogen and carbon dioxide at 55 °C. Strong competition for H2 was observed b

  20. Understanding the azeotropic diethyl carbonate-water mixture by structural and energetic characterization of DEC(H2O)(n) heteroclusters.

    Science.gov (United States)

    Ripoll, Juan D; Mejía, Sol M; Mills, Matthew J L; Villa, Aída L

    2015-04-01

    Diethyl carbonate (DEC) is an oxygenated fuel additive. During its synthesis through a promising green process, a DEC-water azeotrope is formed, which decreases DEC production efficiency in the gas phase. Molecular information about this system is scarce but could be of benefit in understanding (and potentially improving) the synthetic process. Therefore, we report a detailed computational study of the conformers of DEC, and their microsolvation with up to four water molecules, with the goal of understanding the observed 1:3 DEC:H2O molar ratio. The most stable DEC conformers (with mutual energy differences < 1.5 kcal mol(-1)) contribute to the energetic and structural properties of the complexes. An exhaustive stochastic exploration of each potential energy surface of DEC-(H2O)n, (where n = 1, 2, 3, 4) heteroclusters discovered 3, 8, 7, and 4 heterodimers, heterotrimers, heterotetramers, and heteropentamers, respectively, at the MP2/6-311++G(d,p) level of theory. DEC conformers and energies of the most stable structures at each heterocluster size were refined using CCSD(T)/6-311++G(d,p). Energy decomposition, electron density topology, and cooperative effects analyses were carried out to determine the relationship between the geometrical features of the heteroclusters and the non-covalent interaction types responsible for their stabilization. Our findings show that electrostatic and exchange energies are responsible for heterocluster stabilization, and also suggest a mutual weakening among hydrogen bonds when more than three water molecules are present. All described results are complementary and suggest a structural and energetic explanation at the molecular level for the experimental molar ratio of 1:3 (DEC:H2O) for the DEC-water azeotrope.

  1. CO 2 and H 2O gas exchange of a triticale field: I. Leaf level porometry and upscaling to canopy level

    Science.gov (United States)

    Busch, J.; Lösch, R.; Meixner, F. X.; Ammann, C.

    1996-05-01

    Within the frame of an extended field experiment the CO 2 and H 2O gas exchange between a triticale field and the atmosphere was measured during the period between heading and harvest in the summer of 1995. Diurnal courses of H 2O loss, CO 2 gain and leaf conductance were obtained together with microclimatic parameters for leaves of different insertion levels. Patterns of dependence of leaf gas exchange on microclimatic conditions were determined. Based on the results of porometric measurements and crop structural parameters (LAI) gas exchange was scaled up to canopy level.

  2. Photocatalytic oxidation of nitric oxide from simulated flue gas by wet scrubbing using ultraviolet/TiO2/H2O2 process

    Institute of Scientific and Technical Information of China (English)

    张波; 仲兆平; 付宗明

    2015-01-01

    Nitric oxide (NO) from flue gas is hard to remove because of low solubility and reactivity. A new technology for photocatalytic oxidation of NO using ultraviolet (UV)/TiO2/H2O2 process is studied in an efficient laboratory-scale reactor. Effects of several key operational parameters on NO removal efficiency are studied, including TiO2 content, H2O2 initial concentration, UV lamp power, NO initial content, oxygen volume fraction and TiO2/H2O2 solution volume. The results illustrate that the NO removal efficiency increases with the increasing of H2O2 initial concentration or UV lamp power. Meanwhile, a lower NO initial content or a higher TiO2/H2O2 solution volume will result in higher NO removal efficiency. In addition, oxygen volume fraction has a little effect. The highest NO removal efficiency is achieved at the TiO2 content of 0.75 g/L, H2O2 initial concentration of 2.5 mol/L, UV lamp power of 36 W, NO initial content of 206×10−6 and TiO2/H2O2 solution volume of 600 mL. It is beneficial for the development and application of NO removal from coal-fired flue gas with UV/TiO2/H2O2 process.

  3. Effect of p-GaN layer grown with H2 carrier gas on wall-plug efficiency of high-power LEDs

    Science.gov (United States)

    Lu, Kuan Fu; Lin, Tien Kun; Liou, Jian Kai; Yang, Chyi Da; Lee, Chong Yi; Tsai, Jeng Da

    2017-06-01

    The effect of employing different carrier gases (H2 only and 1:1 vol% N2:H2) in the p-type GaN (p-GaN) layer on the wall-plug efficiency (WPE) of high-power light-emitting diodes (LEDs) is studied. Since GaN crystal could be a two-dimension (2-D) growth mode in H2 ambient, better quality and smoother surface of the p-GaN were obtained. The current spreading performance of the p-GaN layer using H2 alone as the carrier gas was enhanced, resulting in advanced light output power (LOP). In addition, turn-on voltage and dynamic resistance at 500 mA, which can strongly contribute to the WPE, were also reduced by 0.12 V and 0.13 Ω, respectively. The studied device with H2 as the carrier gas in the p-GaN layer (p-H2 layer) exhibits 9.5% and 12.4% improvements in LOP and WPE at 500 mA over the device (N2/H2 = 1:1), as well as significantly better electrostatic discharge robustness. Therefore, the use of a p-H2 layer can effectively improve the performance of GaN-based LEDs for high power applications.

  4. Separation of SF6 from gas mixtures using gas hydrate formation.

    Science.gov (United States)

    Cha, Inuk; Lee, Seungmin; Lee, Ju Dong; Lee, Gang-woo; Seo, Yongwon

    2010-08-15

    This study aims to examine the thermodynamic feasibility of separating sulfur hexafluoride (SF(6)), which is widely used in various industrial fields and is one of the most potent greenhouse gases, from gas mixtures using gas hydrate formation. The key process variables of hydrate phase equilibria, pressure-composition diagram, formation kinetics, and structure identification of the mixed gas hydrates, were closely investigated to verify the overall concept of this hydrate-based SF(6) separation process. The three-phase equilibria of hydrate (H), liquid water (L(W)), and vapor (V) for the binary SF(6) + water mixture and for the ternary N(2) + SF(6) + water mixtures with various SF(6) vapor compositions (10, 30, 50, and 70%) were experimentally measured to determine the stability regions and formation conditions of pure and mixed hydrates. The pressure-composition diagram at two different temperatures of 276.15 and 281.15 K was obtained to investigate the actual SF(6) separation efficiency. The vapor phase composition change was monitored during gas hydrate formation to confirm the formation pattern and time needed to reach a state of equilibrium. Furthermore, the structure of the mixed N(2) + SF(6) hydrate was confirmed to be structure II via Raman spectroscopy. Through close examination of the overall experimental results, it was clearly verified that highly concentrated SF(6) can be separated from gas mixtures at mild temperatures and low pressure conditions.

  5. Slurried solid media for simultaneous water purification and carbon dioxide removal from gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D.; Bourcier, William L.; Viani, Brian

    2013-01-29

    A slurried solid media for simultaneous water purification and carbon dioxide removal from gas mixtures includes the steps of dissolving the gas mixture and carbon dioxide in water providing a gas, carbon dioxide, water mixture; adding a porous solid media to the gas, carbon dioxide, water mixture forming a slurry of gas, carbon dioxide, water, and porous solid media; heating the slurry of gas, carbon dioxide, water, and porous solid media producing steam; and cooling the steam to produce purified water and carbon dioxide.

  6. Slurried solid media for simultaneous water purification and carbon dioxide removal from gas mixtures

    Science.gov (United States)

    Aines, Roger D.; Bourcier, William L.; Viani, Brian

    2013-01-29

    A slurried solid media for simultaneous water purification and carbon dioxide removal from gas mixtures includes the steps of dissolving the gas mixture and carbon dioxide in water providing a gas, carbon dioxide, water mixture; adding a porous solid media to the gas, carbon dioxide, water mixture forming a slurry of gas, carbon dioxide, water, and porous solid media; heating the slurry of gas, carbon dioxide, water, and porous solid media producing steam; and cooling the steam to produce purified water and carbon dioxide.

  7. Characterization of Reduced Graphene Oxide (rGO-Loaded SnO2 Nanocomposite and Applications in C2H2 Gas Detection

    Directory of Open Access Journals (Sweden)

    Lingfeng Jin

    2016-12-01

    Full Text Available Acetylene (C2H2 gas sensors were developed by synthesizing a reduced graphene oxide (rGO-loaded SnO2 hybrid nanocomposite via a facile two-step hydrothermal method. Morphological characterizations showed the formation of well-dispersed SnO2 nanoparticles loaded on the rGO sheets with excellent transparency and obvious fold boundary. Structural analysis revealed good agreement with the standard crystalline phases of SnO2 and rGO. Gas sensing characteristics of the synthesized materials were carried out in a temperature range of 100–300 °C with various concentrations of C2H2 gas. At 180 °C, the SnO2–rGO hybrid showed preferable detection of C2H2 with high sensor response (12.4 toward 50 ppm, fast response-recovery time (54 s and 23 s, limit of detection (LOD of 1.3 ppm and good linearity, with good selectivity and long-term stability. Furthermore, the possible gas sensing mechanism of the SnO2–rGO nanocomposites for C2H2 gas were summarized and discussed in detail. Our work indicates that the addition of rGO would be effective in enhancing the sensing properties of metal oxide-based gas sensors for C2H2 and may make a contribution to the development of an excellent ppm-level gas sensor for on-line monitoring of dissolved C2H2 gas in transformer oil.

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

    Science.gov (United States)

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

    2016-11-01

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

  9. Animal flight mechanics in physically variable gas mixtures

    Science.gov (United States)

    Dudley; Chai

    1996-01-01

    Empirical studies of animal flight performance have generally been implemented within the contemporary atmosphere. Experimental alteration of the physical composition of gas mixtures, however, permits construction of novel flight media and the non-invasive manipulation of flight biomechanics. For example, replacement of atmospheric nitrogen with various noble gases results in a tenfold variation in air density at a constant oxygen concentration. Such variation in air density correspondingly elicits extraordinary biomechanical effort from flying animals; hummingbirds and euglossine orchid bees hovering in such low-density but normoxic mixtures have demonstrated exceptionally high values for the mechanical power output of aerobic flight muscle. As with mechanical power, lift coefficients during hovering increase at low air densities in spite of a concomitant decline in the Reynolds number of the wings. The physical effects of variable gas density may also be manifest in morphological and physiological adaptations of animals to flight across altitudinal gradients. Global variation in atmospheric composition during the late Paleozoic may also have influenced the initial evolution and subsequent diversification of ancestral pterygotes. For the present-day experimenter, the use of physically variable flight media represents a versatile opportunity to explore the range of kinematic and aerodynamic modulation available to flying animals.

  10. Modeling phase equilibria for acid gas mixtures using the CPA equation of state. Part II: Binary mixtures with CO2

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Kontogeorgis, Georgios; Michelsen, Michael Locht

    2011-01-01

    In Part I of this series of articles, the study of H2S mixtures has been presented with CPA. In this study the phase behavior of CO2 containing mixtures is modeled. Binary mixtures with water, alcohols, glycols and hydrocarbons are investigated. Both phase equilibria (vapor–liquid and liquid......, alcohols and glycols) are considered, the importance of cross-association is investigated. The cross-association is accounted for either via combining rules or using a cross-solvation energy obtained from experimental spectroscopic or calorimetric data or from ab initio calculations. In both cases two...

  11. The CO-to-H2 Conversion Factor and Dust-to-Gas Ratio on Kiloparsec Scales in Nearby Galaxies

    CERN Document Server

    Sandstrom, K M; Walter, F; Bolatto, A D; Croxall, K V; Draine, B T; Wilson, C D; Wolfire, M; Calzetti, D; Kennicutt, R C; Aniano, G; Meyer, J Donovan; Usero, A; Bigiel, F; Brinks, E; de Blok, W J G; Crocker, A; Dale, D; Engelbracht, C W; Galametz, M; Groves, B; Hunt, L K; Koda, J; Kreckel, K; Linz, H; Meidt, S; Pellegrini, E; Rix, H -W; Roussel, H; Schinnerer, E; Schruba, A; Schuster, K -F; Skibba, R; van der Laan, T; Appleton, P; Armus, L; Brandl, B; Gordon, K; Hinz, J; Krause, O; Montiel, E; Sauvage, M; Schmiedeke, A; Smith, J D T; Vigroux, L

    2012-01-01

    We present maps of the CO-to-H2 conversion factor (alpha_co) and dust-to-gas ratio (DGR) in 26 nearby, star-forming galaxies with ~kiloparsec spatial resolution. We have simultaneously solved for alpha_co and DGR by assuming that the DGR is approximately constant on kpc scales. With this assumption, we can combine maps of dust mass surface density, CO integrated intensity and HI column density to solve for both alpha_co and DGR with no assumptions about their value or dependence on metallicity or other parameters. Such a study has just become possible with the availability of high resolution far-IR maps from the Herschel key program KINGFISH, 12CO J=(2-1) maps from the IRAM 30m large program HERACLES and HI 21-cm line maps from THINGS. We use a fixed ratio between the (2-1) and (1-0) lines to present our alpha_co results on the more typically used 12CO J=(1-0) scale and show using literature measurements that variations in the line ratio do not effect our results. In total, we derive 782 individual solutions ...

  12. Kinetics of thermal reaction HOCl ⇄ H(2 S) + OCl( X 2Π i ) in gas phase

    Science.gov (United States)

    Begović, N.; Marković, Z.; Anić, S.

    2011-12-01

    The kinetics of gas reaction HOCl\\underset{{k_r }}{overset{{k_f }}{longleftrightarrow}}H(^2 S) + OCl(X^2 Pi _i ) was analyzed by the MP4 method. In the temperature range of 100-373 K the rate constants k f and k r and equilibrium constant K were changed from 1.10 × 10-220 to 1.17 × 10-52 s-1, from 2.89 × 10-16 to 1.68 × 10-5s-1 and from 3.80 × 10-205 to 6.96 × 10-48 respectively. In the above temperature range, the activation energy of the forward reaction ( E f) is 105.05 kcal/mol. In the same temperature interval there are two kinetic domains for the reverse reaction with activation energies ( E r1 = 5.53 kcal/mol when T is 100-273 K and E r2 = 14.50 kcal/mol when T is 273-373 K, respectively.

  13. CO-dark molecular gas at high redshift: very large H2 content and high pressure in a low-metallicity damped Lyman alpha system

    Science.gov (United States)

    Balashev, S. A.; Noterdaeme, P.; Rahmani, H.; Klimenko, V. V.; Ledoux, C.; Petitjean, P.; Srianand, R.; Ivanchik, A. V.; Varshalovich, D. A.

    2017-09-01

    We present a detailed analysis of an H2-rich, extremely strong intervening damped Ly α absorption system (DLA) at zabs = 2.786 towards the quasar J 0843+0221, observed with the Ultraviolet and Visual Echelle Spectrograph on the Very Large Telescope. The total column density of molecular (resp. atomic) hydrogen is log N(H2) = 21.21 ± 0.02 (resp. log N(H i) = 21.82 ± 0.11), making it to be the first case in quasar absorption line studies with H2 column density as high as what is seen in 13CO-selected clouds in the Milky Way. We find that this system has one of the lowest metallicity detected among H2-bearing DLAs, with [Zn/H] = -1.52^{+0.08}_{-0.10}. This can be the reason for the marked differences compared to systems with similar H2 column densities in the local Universe: (i) the kinetic temperature, T ∼ 120 K, derived from the J = 0, 1 H2 rotational levels is at least twice higher than expected; (ii) there is little dust extinction with AV 2 × 1023 cm-2/(km s-1 K), in the very low metallicity gas. Low CO and high H2 contents indicate that this system represents 'CO-dark/faint' gas. We investigate the physical conditions in the H2-bearing gas using the fine-structure levels of C i, C ii, Si ii and the rotational levels of HD and H2. We find the number density to be about n ∼ 260-380 cm-3, implying a high thermal pressure of 3-5 × 104 cm-3 K. We further identify a trend of increasing pressure with increasing total hydrogen column density. This independently supports the suggestion that extremely strong DLAs (with log N(H) ∼22) probe high-z galaxies at low impact parameters.

  14. A New Equation of State for CCS Pipeline Transport: Calibration of Mixing Rules for Binary Mixtures of CO2 with N2, O2 and H2

    CERN Document Server

    Demetriades, Thomas A

    2015-01-01

    One of the aspects currently holding back commercial scale deployment of carbon capture and storage (CCS) is an accurate understanding of the thermodynamic behaviour of carbon dioxide and relevant impurities during the pipeline transport stage. In this article we develop a general framework for deriving pressure-explicit EoS for impure CO2. This flexible framework facilitates ongoing development of custom EoS in response to new data and computational applications. We use our method to generalise a recent EoS for pure CO2 [Demetriades et al. Proc IMechE Part E, 227 (2013) pp. 117] to binary mixtures with N2, O2 and H2, obtaining model parameters by fitting to experiments made under conditions relevant to CCS-pipeline transport. Our model pertains to pressures up to 16MPa and temperatures between 273K and the critical temperature of pure CO2. In this region, we achieve close agreement with experimental data. When compared to the GERG EoS, our EoS has a comparable level of agreement with CO2 -N2 VLE experiments ...

  15. 10 CFR 503.38 - Permanent exemption for certain fuel mixtures containing natural gas or petroleum.

    Science.gov (United States)

    2010-01-01

    ... natural gas or petroleum. 503.38 Section 503.38 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS... mixtures containing natural gas or petroleum. (a) Eligibility. Section 212(d) of the Act provides for a... proposes to use a mixture of natural gas or petroleum and an alternate fuel as a primary energy source; (2...

  16. Collision-induced line parameters for the (2 ← 0) overtone band of HCl (1.76 μm) in binary mixtures with H2 and CH4

    Science.gov (United States)

    Domanskaya, Alexandra V.; Li, Gang; Tran, Ha; Gisi, Michael; Ebert, Volker

    2017-09-01

    We present experimental results on pressure broadening and shift coefficients in the first vibrational overtone band of HCl in gaseous mixtures with H2 and CH4 at room temperature. The whole set of collisional parameters for HCl-CH4 is novel. Most of the data for HCl-H2 system is also published for the first time. Our results have a precision of about 2% or better for shifts and below 1% for broadening in the band center.

  17. Transport Properties and Thermodynamic Processes for Liquid Fuels and Gas Mixtures of N2, O2, H2 and H2O

    Science.gov (United States)

    2001-03-01

    effective kinetic diameter model makes it possible to describe the viscosity of liquids and gases in wide ranges of temperature and density. The performed...M.P.Voronin. Universal equation for viscosity of liquids and gases. Thermo-Physics of High Temperatures, V.2 1, N3, 1983. [11] M.P. Voronin. Mathematical

  18. Investigation of Gas-Sensing Property of Acid-Deposited Polyaniline Thin-Film Sensors for Detecting H2S and SO2

    Directory of Open Access Journals (Sweden)

    Xingchen Dong

    2016-11-01

    Full Text Available Latent insulation defects introduced in manufacturing process of gas-insulated switchgears can lead to partial discharge during long-time operation, even to insulation fault if partial discharge develops further. Monitoring of decomposed components of SF6, insulating medium of gas-insulated switchgear, is a feasible method of early-warning to avoid the occurrence of sudden fault. Polyaniline thin-film with protonic acid deposited possesses wide application prospects in the gas-sensing field. Polyaniline thin-film sensors with only sulfosalicylic acid deposited and with both hydrochloric acid and sulfosalicylic acid deposited were prepared by chemical oxidative polymerization method. Gas-sensing experiment was carried out to test properties of new sensors when exposed to H2S and SO2, two decomposed products of SF6 under discharge. The gas-sensing properties of these two sensors were compared with that of a hydrochloric acid deposited sensor. Results show that the hydrochloric acid and sulfosalicylic acid deposited polyaniline thin-film sensor shows the most outstanding sensitivity and selectivity to H2S and SO2 when concentration of gases range from 10 to 100 μL/L, with sensitivity changing linearly with concentration of gases. The sensor also possesses excellent long-time and thermal stability. This research lays the foundation for preparing practical gas-sensing devices to detect H2S and SO2 in gas-insulated switchgears at room temperature.

  19. Herschel Far-Infrared Spectral-mapping of Orion BN/KL Outflows: Spatial distribution of excited CO, H2O, OH, O and C+ in shocked gas

    CERN Document Server

    Goicoechea, Javier R; Cernicharo, Jose; Neufeld, David A; Vavrek, Roland; Bergin, Edwin A; Cuadrado, Sara; Encrenaz, Pierre; Etxaluze, Mireya; Melnick, Gary J; Polehampton, Edward

    2014-01-01

    We present ~2'x2' spectral-maps of Orion BN/KL outflows taken with Herschel at ~12'' resolution. For the first time in the far-IR domain, we spatially resolve the emission associated with the bright H2 shocked regions "Peak 1" and "Peak 2" from that of the Hot Core and ambient cloud. We analyze the ~54-310um spectra taken with the PACS and SPIRE spectrometers. More than 100 lines are detected, most of them rotationally excited lines of 12CO (up to J=48-47), H2O, OH, 13CO, and HCN. Peaks 1/2 are characterized by a very high L(CO)/L(FIR)~5x10^{-3} ratio and a plethora of far-IR H2O emission lines. The high-J CO and OH lines are a factor ~2 brighter toward Peak 1 whereas several excited H2O lines are ~50% brighter toward Peak 2. A simplified non-LTE model allowed us to constrain the dominant gas temperature components. Most of the CO column density arises from Tk~200-500 K gas that we associate with low-velocity shocks that fail to sputter grain ice mantles and show a maximum gas-phase H2O/CO~10^{-2} abundance r...

  20. Molecular gas in low-metallicity starburst galaxies: Scaling relations and the CO-to-H$_2$ conversion factor

    CERN Document Server

    Amorín, Ricardo; Aguerri, J A L; Planesas, P

    2015-01-01

    We study the molecular content and the star formation efficiency of 21 Blue Compact Dwarfs (BCDs). We present CO(1-0) and (2-1) observations, further supplemented with additional CO measurements and multiwavelength ancillary data from the literature. We find the CO luminosity to be correlated with the stellar and HI masses, SFR tracers, the size of the starburst and its metallicity. BCDs appear offset from the Schmidt-Kennicutt (SK) law, showing extremely low ($\\lesssim$0.1 Gyr) H2 and H2+HI depletion timescales. The departure from the SK law is smaller when considering H2+HI rather than H2 only, and is larger for BCDs with lower metallicity and higher specific SFR. Thus, the molecular fraction and H2 depletion timescale of BCDs is found to be strongly correlated with metallicity. Using this and assuming that the empirical correlation found between the specific SFR and galaxy-averaged H2 depletion timescale of more metal-rich galaxies extends to lower masses, we derive a metallicity-dependent CO-to-H2 convers...

  1. Recovery Technology of Hydrogen from Refinery Dry Gas%炼厂干气回收制H2技术

    Institute of Scientific and Technical Information of China (English)

    王红伟; 徐静莉

    2012-01-01

    Membrane separation-pressure swing adsorption integration technique was used to recover hydrogen from dry gas in order to utilize effectively catalytic gas from Jilin oil refinery of petroleum corporation. Recovery rate of hydrogen could reach above 80% and concentration of recovery hydrogen was above 95 mol% by the technology.%为有效利用吉林石化炼油厂催化干气,对现有的制氢技术进行了研究,确定了采用膜分离-变压吸附集成工艺技术进行干气回收制H2,使H2回收率〉80%,回收H2浓度〉95mol%。

  2. Oxidation and Condensation of Zinc Fume From Zn-CO2-CO-H2O Streams Relevant to Steelmaking Off-Gas Systems

    Science.gov (United States)

    Bronson, Tyler M.; Ma, Naiyang; Zhu, Liang Zhu; Sohn, Hong Yong

    2017-04-01

    The objective of this research was to study the condensation of zinc vapor to metallic zinc and zinc oxide solid under varying environments to investigate the feasibility of in-process separation of zinc from steelmaking off-gas dusts. Water vapor content, temperature, degree of cooling, gas composition, and initial zinc partial pressure were varied to simulate the possible conditions that can occur within steelmaking off-gas systems, limited to Zn-CO2-CO-H2O gas compositions. The temperature of deposition and the effect of rapidly quenching the gas were specifically studied. A homogeneous nucleation model for applicable experiments was applied to the analysis of the experimental data. It was determined that under the experimental conditions, oxidation of zinc vapor by H2O or CO2 does not occur above 1108 K (835 °C) even for highly oxidizing streams (CO2/CO = 40/7). Rate expressions that correlate CO2 and H2O oxidation rates to gas composition, partial pressure of water vapor, temperature, and zinc partial pressure were determined to be as follows: Rate( mol/m2 s ) = 406 \\exp ( - 50.2 kJ/mol/RT )( p_Zn p_{CO2 - p_CO /K_{eq,CO2 ) mol/m2 × s Rate( mol/m2 s ) = 32.9 \\exp ( - 13.7 kJ/mol/RT )( p_Zn p_{H2 O - p_{H2 /K_{eq,H2 O ) mol/m2 × s It was proven that a rapid cooling rate (500 K/s) significantly increases the ratio of metallic zinc to zinc oxide as opposed to a slow cooling rate (250 K/s). SEM analysis found evidence of heterogeneous growth of ZnO as well as of homogeneous formation of metallic zinc. The homogeneous nucleation model fit well with experiments where only metallic zinc deposited. An expanded model with rates of oxidation by CO2 and H2O as shown was combined with the homogenous nucleation model and then compared with experimental data. The calculated results based on the model gave a reasonable fit to the measured data. For the conditions used in this study, the rate equations for the oxidation of zinc by carbon dioxide and water vapor as well

  3. Extraction of Mg(OH)2 from Mg silicate minerals with NaOH assisted with H2O: implications for CO2 capture from exhaust flue gas.

    Science.gov (United States)

    Madeddu, Silvia; Priestnall, Michael; Godoy, Erik; Kumar, R Vasant; Raymahasay, Sugat; Evans, Michael; Wang, Ruofan; Manenye, Seabelo; Kinoshita, Hajime

    2015-01-01

    The utilisation of Mg(OH)2 to capture exhaust CO2 has been hindered by the limited availability of brucite, the Mg(OH)2 mineral in natural deposits. Our previous study demonstrated that Mg(OH)2 can be obtained from dunite, an ultramafic rock composed of Mg silicate minerals, in highly concentrated NaOH aqueous systems. However, the large quantity of NaOH consumed was considered an obstacle for the implementation of the technology. In the present study, Mg(OH)2 was extracted from dunite reacted in solid systems with NaOH assisted with H2O. The consumption of NaOH was reduced by 97% with respect to the NaOH aqueous systems, maintaining a comparable yield of Mg(OH)2 extraction, i.e. 64.8-66%. The capture of CO2 from a CO2-N2 gas mixture was tested at ambient conditions using a Mg(OH)2 aqueous slurry. Mg(OH)2 almost fully dissolved and reacted with dissolved CO2 by forming Mg(HCO3)2 which remained in equilibrium storing the CO2 in the aqueous solution. The CO2 balance of the process was assessed from the emissions derived from the power consumption for NaOH production and Mg(OH)2 extraction together with the CO2 captured by Mg(OH)2 derived from dunite. The process resulted as carbon neutral when dunite is reacted at 250 °C for durations of 1 and 3 hours and CO2 is captured as Mg(HCO3)2.

  4. Numerical simulation for explosion wave propagation of combustible mixture gas

    Institute of Scientific and Technical Information of China (English)

    WANG Cheng; NING Jian-guo; MA Tian-bao

    2008-01-01

    A two-dimensional multi-material code was indigenously developed to investigate the effects of duct boundary conditions and ignition positions on the propagation law of explosion wave for hydrogen and methane-based combustible mixture gas. In the code, Young's technique was employed to track the interface between the explosion products and air, and combustible function model was adopted to simulate ignition process. The code was employed to study explosion flow field inside and outside the duct and to obtain peak pressures in different boundary conditions and ignition positions. Numerical results suggest that during the propagation in a duct, for point initiation, the curvature of spherical wave front gradually decreases and evolves into plane wave. Due to the multiple reflections on the duct wall, multi-peak values appear on pressure-time curve, and peak pressure strongly relies on the duct boundary conditions and ignition position. When explosive wave reaches the exit of the duct, explosion products expand outward and forms shock wave in air. Multiple rarefaction waves also occur and propagate upstream along the duct to decrease the pressure in the duct. The results are in agreement with one-dimensional isentropic gas flow theory of the explosion products, and indicate that the ignition model and multi-material interface treatment method are feasible.

  5. Experimental Optimization and Modeling of Sodium Sulfide Production from H2S-Rich Off-Gas via Response Surface Methodology and Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Bashipour Fatemeh

    2017-03-01

    Full Text Available The existence of hydrogen sulfide (H2S in the gas effluents of oil, gas and petrochemical industries causes environmental pollution and equipment corrosion. These gas streams, called off-gas, have high H2S concentration, which can be used to produce sodium sulfide (Na2S by H2S reactive absorption. Na2S has a wide variety of applications in chemical industries. In this study, the reactive absorption process was performed using a spray column. Response Surface Methodology (RSM was applied to design and optimize experiments based on Central Composite Design (CCD. The individual and interactive effects of three independent operating conditions on the weight percent of the produced Na2S (Y were investigated by RSM: initial NaOH concentration (10-20% w/w, scrubbing solution temperature (40-60 °C and liquid-to-gas volumetric ratio (15 × 10−3 to 25 × 10−3. Furthermore, an Artificial Neural Network (ANN model was used to predict Y. The results from RSM and ANN models were compared with experimental data by the regression analysis method. The optimum operating conditions specified by RSM resulted in Y of 15.5% at initial NaOH concentration of 19.3% w/w, scrubbing solution temperature of 40 °C and liquid-to-gas volumetric ratio of 24.6 × 10−3 v/v.

  6. Effect of the gas temperature and pressure on the nucleation time of particles in low pressure Ar-C2H2 rf plasmas

    Science.gov (United States)

    Lin, Jiashu; Henault, Marie; Orazbayev, Sagi; Boufendi, Laïa; Takahashi, Kazuo; Al Farabi Kazakh National University Collaboration; Kyoto Institute Of Technology Team; Gremi Team

    2016-09-01

    Particle formation in low pressure plasmas is a 3-step process. The first one corresponds to the nucleation and growth of nano-crystallites by ion-molecular reactions, the agglomeration phase to form large particles, and the growth by radical deposition on the particle surface. The nucleation phase was demonstrated to be sensitive to gas temperature and pressure. In this work, time of nucleation phase of particles formation in low pressure cold rf C2H2/Ar plasmas studied by varying gas temperature from 265 K to 375 K, gas pressure from 0.4 mbar to 0.8 mbar and rf power from 6 W to 20 W. The ratio of C2H2/Ar is fixed to 2/98 in terms of pressure. Several previous works reported that particle formation takes a few sec at room temperature in C2 H2 plasmas and the time is much shorter than 0.1 s in SiH4 plasmas. Time evolution of self-bias voltage was mainly used to determine nucleation time. The self-bias voltage was modified by phase transition between the steps from nucleation to coagulation. The experimental results showed that the nucleation time increased with gas temperature, decreased with gas pressure and discharge power. At constant gas pressure of 0.4 mbar and discharge power of 6 W, for example, the nucleation time increased from 5 sec to 30 sec with increas

  7. Formation of ettringite, Ca 6Al 2(SO 4) 3(OH) 12·26H 2O, AFt, and monosulfate, Ca 4Al 2O 6(SO 4)·14H 2O, AFm-14, in hydrothermal hydration of Portland cement and of calcium aluminum oxide—calcium sulfate dihydrate mixtures studied by in situ synchrotron X-ray powder diffraction

    Science.gov (United States)

    Christensen, Axel Nørlund; Jensen, Torben R.; Hanson, Jonathan C.

    2004-06-01

    In the hydration of calcium aluminum oxide-gypsum mixtures, i.e., Ca 3Al 2O 6, Ca 12Al 14O 33 and CaSO 4·2H 2O, the reaction products can be ettringite, Ca 6Al 2(SO 4) 3(OH) 12·26H 2O, monosulfate, Ca 4Al 2O 6(SO 4)·14H 2O, or the calcium aluminum oxide hydrate, Ca 4Al 2O 7·19H 2O. Ettringite is formed if sufficient CaSO 4·2H 2O is present in the mixture. Ettringite is converted to monosulfate when all CaSO 4·2H 2O is consumed in the synthesis of ettringite. The reactions were investigated in the temperature range 25-170°C using in situ synchrotron X-ray powder diffraction. This technique allows the study of very fast chemical reactions that are observed here under hydrothermal conditions. A new experimental approach was developed to perform in situ mixing of the reactants during X-ray data collection.

  8. 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...

  9. Quantitative NMR spectroscopy for gas analysis for production of primary reference gas mixtures.

    Science.gov (United States)

    Meyer, K; Rademann, K; Panne, U; Maiwald, M

    2017-02-01

    Due to its direct correlation to the number of spins within a sample quantitative NMR spectroscopy (qNMR) is a promising method with absolute comparison abilities in complex systems in technical, as well as metrological applications. Most of the samples studied with qNMR are in liquid state in diluted solutions, while gas-phase applications represent a rarely applied case. Commercially available NMR equipment was used for purity assessment of liquid and liquefied hydrocarbons serving as raw materials for production of primary reference gas standards. Additionally, gas-phase studies were performed within an online NMR flow probe, as well as in a high-pressure NMR setup to check feasibility as verification method for the composition of gas mixtures. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Isotopic evidence of TSR origin for natural gas bearing high H2S contents within the Feixianguan Formation of the northeastern Sichuan Basin, southwestern China

    Institute of Scientific and Technical Information of China (English)

    ZHU Guangyou; ZHANG Shuichang; LIANG Yingbo; DAI Jinxing; LI Jian

    2005-01-01

    The northeastern area of Sichuan Basin, southwestern China, is the area with the maximal reserve of natural gas containing higher hydrogen sulphide (H2S) that has been found among the petroliferous basins of China, with the proven and controlled gas reserve of more than 200 billion cubic meters. These gas pools, with higher H2S contents averaging 9%, some 17%, are mainly distributed on structural belts of Dukouhe, Tieshanpo, Luojiazhai, Puguang, etc., while the oolitic-shoal dolomite of the Triassic Feixianguan Fm. (T1f) is the reservoir. Although many scholars regard the plentiful accumulation of H2S within the deep carbonate reservoir as the result of Thermochemical Sulfate Reduction (TSR), however, the process of TSR as well as its residual geological and geochemical evidence is still not quite clear. Based on the carbon isotopic analysis of carbonate strata and secondary calcite, etc., together with the analysis of sulfur isotopes within H2S, sulphur, gypsum, iron pyrites, etc., as well as other aspects including the natural gas composition, carbon isotopes of hydrocarbons reservoir petrology, etc., it has been proved that the above natural gas is a product of TSR. The H2S, sulphur and calcite result from the participation of TSR reactions by hydrocarbon gas. During the process for hydrocarbons being consumed due to TSR, the carbons within the hydrocarbon gas participate in the reactions and finally are transferred into the secondary calcite, and become the carbon source of secondary calcite, consequently causing the carbon isotopes of the secondary calcite to be lower (-18.2‰). As for both the intermediate product of TSR, i.e. sulfur, and its final products, i.e. H2S and iron pyrites, their sulfur elements are all sourced from the sulfate within the Feixianguan Fm. During the fractional processes of sulfur isotopes, the bond energy leads to the 32S being released firstly, and the earlier it is released, the lower δ34S values for the generated sulphide (H2S

  11. Effectiveness and reaction networks of H2O2 vapor with NH3 gas for decontamination of the toxic warfare nerve agent, VX on a solid surface.

    Science.gov (United States)

    Gon Ryu, Sam; Wan Lee, Hae

    2015-01-01

    The nerve agent, O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate (VX) must be promptly eliminated following its release into the environment because it is extremely toxic, can cause death within a few minutes after exposure, acts through direct skin contact as well as inhalation, and persists in the environment for several weeks after release. A mixture of hydrogen peroxide vapor and ammonia gas was examined as a decontaminant for the removal of VX on solid surfaces at ambient temperature, and the reaction products were analyzed by gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance spectrometry (NMR). All the VX on glass wool filter disks was found to be eliminated after 2 h of exposure to the decontaminant mixtures, and the primary decomposition product was determined to be non-toxic ethyl methylphosphonic acid (EMPA); no toxic S-[2-(diisopropylamino)ethyl] methylphosphonothioic acid (EA-2192), which is usually produced in traditional basic hydrolysis systems, was found to be formed. However, other by-products, such as toxic O-ethyl S-vinyl methylphosphonothioate and (2-diisopropylaminoethyl) vinyl disulfide, were detected up to 150 min of exposure to the decontaminant mixture; these by-products disappeared after 3 h. The two detected vinyl byproducts were identified first in this study with the decontamination system of liquid VX on solid surfaces using a mixture of hydrogen peroxide vapor and ammonia gas. The detailed decontamination reaction networks of VX on solid surfaces produced by the mixture of hydrogen peroxide vapor and ammonia gas were suggested based on the reaction products. These findings suggest that the mixture of hydrogen peroxide vapor and ammonia gas investigated in this study is an efficient decontaminant mixture for the removal of VX on solid surfaces at ambient temperature despite the formation of a toxic by-product in the reaction process.

  12. CO/H2, C/CO, OH/CO, and OH/O2 in dense interstellar gas: from high ionization to low metallicity

    Science.gov (United States)

    Bialy, Shmuel; Sternberg, Amiel

    2015-07-01

    We present numerical computations and analytic scaling relations for interstellar ion-molecule gas-phase chemistry down to very low metallicities (10-3 × solar), and/or up to high driving ionization rates. Relevant environments include the cool interstellar medium (ISM) in low-metallicity dwarf galaxies, early enriched clouds at the reionization and Pop-II star formation era, and in dense cold gas exposed to intense X-ray or cosmic ray sources. We focus on the behaviour for H2, CO, CH, OH, H2O and O2, at gas temperatures ˜100 K, characteristic of a cooled ISM at low metallicities. We consider shielded or partially shielded one-zone gas parcels, and solve the gas-phase chemical rate equations for the steady-state `metal-molecule abundances for a wide range of ionization parameters, ζ/n, and metallicties, Z '. We find that the OH abundances are always maximal near the H-to-H2 conversion points, and that large OH abundances persist at very low metallicities even when the hydrogen is predominantly atomic. We study the OH/O2, C/CO and OH/CO abundance ratios, from large to small, as functions of ζ/n and Z '. Much of the cold dense ISM for the Pop-II generation may have been OH-dominated and atomic rather than CO-dominated and molecular.

  13. Sensitive, Selective, and Fast Detection of ppb-Level H2S Gas Boosted by ZnO-CuO Mesocrystal

    Science.gov (United States)

    Guo, Yanan; Gong, Miaomiao; Li, Yushu; Liu, Yunling; Dou, Xincun

    2016-10-01

    ZnO-CuO mesocrystal was prepared via topotactic transformation using one-step direct annealing of aqueous precursor solution and assembled into a H2S sensor. The ZnO-CuO mesocrystal-based sensor possesses good linearity and high sensitivity in the low-concentration range (10-200 ppb). Compared to pure CuO, the as-prepared ZnO-CuO mesocrystal sensor exhibited superior H2S sensing performance with a response ranging from 8.6 to 152 % towards H2S concentrations from 10 ppb to 10 ppm when applied at the optimized working temperature of 125 °C. The sensor showed excellent repeatability and good selectivity towards H2S gas even at a concentration four orders of magnitude lower than the interfering gases, such as H2, CO2, CO, NO2, acetone, and NH3. The improved sensitivity could be attributed partially to the effective diffusion of analyte gas through the mesocrystal surface and the abundant accessible active sites. Moreover, the nanoscale p-n junctions within the mesocrystal, which could effectively manipulate the local charge carrier concentration, are also beneficial to boost the sensing performance.

  14. Comparative 4-E analysis of a bottoming pure NH3 and NH3-H2O mixture based power cycle for condenser waste heat recovery

    Science.gov (United States)

    Khankari, Goutam; Karmakar, Sujit

    2017-06-01

    boiling temperature of NH3-H2O binary mixture in KCS11 and resulting in less irreversibility during the process of heat transfer. Levelized Cost of Electricity (LCoE) generation and the cost of implementation of ORC integrated power plant is about Rs.1.767/- per kWh and Rs. 2.187/- per kg of fuel saved, respectively whereas, the LCoE for KCS11 based combined power plant is slightly less than the ORC based combined cycle power plant and estimated as about Rs.1.734 /- per kWh. The cost of implementation of KCS11 based combined cycle power plant is about Rs. 0.332/- per kg of fuel saved. Though the energy and exergy efficiencies of ORC is better than KCS11 but considering the huge investment for developing the combined cycle power plant based on ORC in comparison with KCS11 below the operating pressure of 14 bar, KCS11 is superior than NH3 based ORC.

  15. 用于含氢混合物的阻火器%Flame arrestor for gas mixtures containing hydrogen

    Institute of Scientific and Technical Information of China (English)

    宦建波

    2012-01-01

    在石化企业中,燃料气经常是含氢气体混合物,氢气在混合物中体积分数为27%时最大试验安全间隙(MESG)为0.29 mm,爆炸性级别为ⅡC,石化设备中的燃料气中氢体积分数达不到27%,燃料气的MESG应当大于0.29 mm.通过分析国家和行业标准,对用于含有氢气的气体混合物燃料气防爆阻火器级别进行分析,认为爆炸性级别应当低于ⅡC,为ⅡA或者ⅡB,最确切的做法是将气体混合物的组成和操作条件送有关单位,应当按照GB3836.11的方法试验确定MESG,根据MESG确定含氢气体混合物爆炸性级别.%In petrochemical plants, fuel gas is often a mixture containing hydrogen. The maximum experiment safety gap ( MESG) is 0. 29 when the hydrogen in mixture gas is 27% and explosion class is II C. As the hydrogen in fuel gas in petrochemical equipment is lower than 27% , the MESG of fuel gas should be greater than 0. 29. The study of applicable national and industrial codes and standards as well as the analysis of class of explosion-proof flame arrestor for gas mixture containing H2 conclude that the explosion class of flame arrestor should be lower than II C, I. E. Either II A or II B. The most accurate way is to send the data of compositions of gas mixture and operation conditions to qualified institutions to determine MESG based upon the experiment in accordance with GB 3836. 11 and explosion class of gas mixture containing H2 based upon MESG.

  16. Infrared Studies of Molecular Shocks in the Supernova Remnant HB21: I. Thermal Admixture of Shocked H_2 Gas in the North

    CERN Document Server

    Shinn, Jong-Ho; Burton, Michael G; Lee, Ho-Gyu; Moon, Dae-Sik

    2008-01-01

    We present near- and mid-infrared observations on the shock-cloud interaction region in the northern part of the supernova remnant HB21, performed with the InfraRed Camera (IRC) aboard AKARI satellite and the Wide InfraRed Camera (WIRC) at the Palomar 5 m telescope. The IRC 7 um (S7), 11 um (S11), and 15 um (L15) band images and the WIRC H2 v = 1 -> 0 S(1) 2.12 um image show similar shock-cloud interaction features. We chose three representative regions, and analyzed their IRC emissions through comparison with H2 line emissions of several shock models. The IRC colors are well explained by the thermal admixture model of H2 gas--whose infinitesimal H2 column density has a power-law relation with the temperature T, dN ~ T^-b dT--with n(H2) ~ 10^3 cm^-3, b ~ 3, and N(H2 ;T > 100K) ~ 3x10^20 cm^-2. The derived b value may be understood by a bow shock picture, whose shape is cycloidal (cuspy) rather than paraboloidal. However, this picture raises another issue that the bow shocks must reside within ~0.01 pc size-sc...

  17. Reactions and Thermochemistry of Alkyl Ions, Cn H2n+1 + (n=1-8), in the Gas Phase

    Science.gov (United States)

    2007-11-02

    isooctane /O2/Ar/NO mixture to be used in shock tube ignition studies is presented. Introduction The development of future aerospace vehicles requires a...the combustion of branched alkanes to model isooctane combustion. Measurements of the spontaneous ignition of isooctane obtained in a rapid...computations regarding the combustion of pure isooctane (i- C8H18), pure ethylbenzene (C8H10), and a 76 vol% isooctane / 24 vol% ethylbenzene mixture with a

  18. The HDO/H2O Ratio in Gas in the Inner Regions of a Low-mass Protostar

    DEFF Research Database (Denmark)

    Jørgensen, Jes Kristian; van Dishoeck, Ewine F.

    2010-01-01

    The HDO/H2O abundance ratio is thought to be a key diagnostic for the evolution of water during the star and planet formation process and thus for its origin on Earth. We here present millimeter-wavelength high angular resolution observations of the deeply embedded protostar NGC 1333-IRAS4B from...... enhanced in the inner ˜50 AU around the protostar relative to what is seen in comets and Earth's oceans and does not support previous suggestions of a generally enhanced HDO/H2O ratio in these systems....

  19. 2D fluid simulations of discharges at atmospheric pressure in reactive gas mixtures

    Science.gov (United States)

    Bourdon, Anne

    2015-09-01

    generated by the discharge, in agreement with experiments. Then, we have studied the production of active species for the different regimes of nanosecond repetitively pulsed discharges. We present the relative importance of gas heating and the production of active species for the ignition of lean H2-air and CH4-air mixtures. This work has been partially supported by the project ANR DRACO (Grant No. ANR-13-IS09-0004).

  20. High-frequency sound wave propagation in binary gas mixtures flowing through microchannels

    Science.gov (United States)

    Bisi, M.; Lorenzani, S.

    2016-05-01

    The propagation of high-frequency sound waves in binary gas mixtures flowing through microchannels is investigated by using the linearized Boltzmann equation based on a Bhatnagar-Gross-Krook (BGK)-type approach and diffuse reflection boundary conditions. The results presented refer to mixtures whose constituents have comparable molecular mass (like Ne-Ar) as well as to disparate-mass gas mixtures (composed of very heavy plus very light molecules, like He-Xe). The sound wave propagation model considered in the present paper allows to analyze the precise nature of the forced-sound modes excited in different gas mixtures.

  1. Catalyst functionalized buffer sorbent pebbles for rapid separation of carbon dioxide from gas mixtures

    Science.gov (United States)

    Aines, Roger D.

    2013-03-12

    A method for separating CO.sub.2 from gas mixtures uses a slurried media impregnated with buffer compounds and coating the solid media with a catalyst or enzyme that promotes the transformation of CO.sub.2 to carbonic acid. Buffer sorbent pebbles with a catalyst or enzyme coating are provided for rapid separation of CO.sub.2 from gas mixtures.

  2. Catalyst functionalized buffer sorbent pebbles for rapid separation of carbon dioxide from gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D

    2015-03-31

    A method for separating CO.sub.2 from gas mixtures uses a slurried media impregnated with buffer compounds and coating the solid media with a catalyst or enzyme that promotes the transformation of CO.sub.2 to carbonic acid. Buffer sorbent pebbles with a catalyst or enzyme coating are provided for rapid separation of CO.sub.2 from gas mixtures.

  3. H2S高CO2高Cl-天然气压力容器设计%Design of pressure vessel for natural gas with high H 2 S,CO2 and Cl- contents

    Institute of Scientific and Technical Information of China (English)

    刘文广; 张毅; 张波

    2014-01-01

    The basic designing practices of pressure vessels for natural gas field with high H2S ,CO2 and Cl- contents were introduced .Meanwhile ,handling of problems appeared during manufacture and inspection process ,as well as basic situations of the pressure vessels after put into production were explained .These measures ensured the safety of the pressure vessels and the successful start-up of the devices to produce qualified natural gas ,condensate oil and corre-sponding affiliated products .All of above made a breakthrough in the large gas field development both at home and abroad ,and the unit was successfully commissioned abroad .The practices and processing suggestions in the approaches also provided new safe and convenient ways to imple-ment in the development of similar gas field abroad ,and provided references in design and con-struction for similar units .%介绍了三高气田(高H2 S、高CO2、高Cl-)压力容器设计的基本作法,同时对制造检验过程中出现问题的处理和试运投产的基本情况作了说明,确保了压力容器的安全,装置一次投运成功,最终生产出合格的天然气、凝析油、相应附属产品。该压力容器突破了国内外大型气田的开发,在国外一次投产成功,为今后国外三高气田的开发走出了一条安全可靠、便利实施的新路,这些作法和处理意见为同行们今后的设计、施工提供了参考。

  4. Dissipation process of binary mixture gas in thermally relativistic flow

    CERN Document Server

    Yano, Ryosuke

    2016-01-01

    In this paper, we discuss dissipation process of the binary mixture gas in the thermally relativistic flow \\textcolor{red}{by focusing on the characteristics of the diffusion flux}. As an analytical object, we consider the relativistic rarefied-shock layer problem around the triangle prism. Numerical results of the diffusion flux are compared with the Navier-Stokes-Fourier (NSF) order approximation of the diffusion flux, which is calculated using the diffusion and thermal-diffusion coefficients by Kox \\textit{et al}. [Physica A, 84, 1, pp.165-174 (1976)]. In the case of the uniform flow with the small Lorentz contraction, the diffusion flux, which is obtained by calculating the relativistic Boltzmann equation, is roughly approximated by the NSF order approximation inside the shock wave, whereas the diffusion flux in the vicinity of the wall is markedly different from the NSF order approximation. The magnitude of the diffusion flux, which is obtained by calculating the relativistic Boltzmann equation, is simil...

  5. Metastable sound speed in gas-liquid mixtures

    Science.gov (United States)

    Bursik, J. W.; Hall, R. M.

    1979-01-01

    A new method of calculating speed of sound for two-phase flow is presented. The new equation assumes no phase change during the propagation of an acoustic disturbance and assumes that only the total entropy of the mixture remains constant during the process. The new equation predicts single-phase values for the speed of sound in the limit of all gas or all liquid and agrees with available two-phase, air-water sound speed data. Other expressions used in the two-phase flow literature for calculating two-phase, metastable sound speed are reviewed and discussed. Comparisons are made between the new expression and several of the previous expressions -- most notably a triply isentropic equation as used, a triply isentropic equation as used, among others, by Karplus and by Wallis. Appropriate differences are pointed out and a thermodynamic criterion is derived which must be satisfied in order for the triply isentropic expression to be thermodynamically consistent. This criterion is not satisfied for the cases examined, which included two-phase nitrogen, air-water, two-phase parahydrogen, and steam-water. Consequently, the new equation derived is found to be superior to the other equations reviewed.

  6. Metal Oxide/Zeolite Combination Absorbs H2S

    Science.gov (United States)

    Voecks, Gerald E.; Sharma, Pramod K.

    1989-01-01

    Mixed copper and molybdenum oxides supported in pores of zeolite found to remove H2S from mixture of gases rich in hydrogen and steam, at temperatures from 256 to 538 degree C. Absorber of H2S needed to clean up gas streams from fuel processors that incorporate high-temperature steam reformers or hydrodesulfurizing units. Zeolites chosen as supporting materials because of their high porosity, rigidity, alumina content, and variety of both composition and form.

  7. Influence of CuO catalyst in the nanoscale range on SnO2 surface for H2S gas sensing applications

    Indian Academy of Sciences (India)

    Vinay Gupta; S Mozumdar; Arijit Choudhuri; K Sreenivas

    2005-10-01

    The dispersal of CuO catalyst on the surface of the semiconducting SnO2 film is found to be of vital importance for improving the sensitivity and the response speed of a SnO2 gas sensor for H2S gas detection. Ultra-thin CuO islands (8 nm thin and 0.6 mm diameter) prepared by evaporating Cu through a mesh and subsequent oxidation yield a fast response speed and recovery. Ultimately nanoparticles of Cu (average size = 15 nm) prepared by a chemical technique using a reverse micelle method involving the reduction of Cu(NO3)2 by NaBH4 exhibited significant improvement in the gas sensing characteristics of SnO2 films. A fast response speed of ∼ 14 s and a recovery time of ∼ 60 s for trace level ∼ 20 ppm H2S gas detection have been recorded. The sensor operating temperature (130°C) is low and the sensitivity ( = 2.06 × 103) is high. It is found that the spreading over of CuO catalyst in the nanoscale range on the surface of SnO2 allows effective removal of excess adsorbed oxygen from the uncovered SnO2 surface due to spill over of hydrogen dissociated from the H2S-CuO interaction.

  8. Applicability of linearized Dusty Gas Model for multicomponent diffusion of gas mixtures in porous solids

    Directory of Open Access Journals (Sweden)

    Marković Jelena

    2007-01-01

    Full Text Available The transport of gaseous components through porous media could be described according to the well-known Fick model and its modifications. It is also known that Fick’s law is not suitable for predicting the fluxes in multicomponent gas mixtures, excluding binary mixtures. This model is still frequently used in chemical engineering because of its simplicity. Unfortunately, besides the Fick’s model there is no generally accepted model for mass transport through porous media (membranes, catalysts etc.. Numerous studies on transport through porous media reveal that Dusty Gas Model (DGM is superior in its ability to predict fluxes in multicomponent mixtures. Its wider application is limited by more complicated calculation procedures comparing to Fick’s model. It should be noted that there were efforts to simplify DGM in order to obtain satisfactory accurate results. In this paper linearized DGM, as the simplest form of DGM, is tested under conditions of zero system pressure drop, small pressure drop, and different temperatures. Published experimental data are used in testing the accuracy of the linearized procedure. It is shown that this simplified procedure is accurate enough compared to the standard more complicated calculations.

  9. Systems and methods for removing components of a gas mixture

    Science.gov (United States)

    None

    2016-09-06

    A system for removing components of a gaseous mixture is provided comprising: a reactor fluid containing vessel having conduits extending therefrom, aqueous fluid within the reactor, the fluid containing a ligand and a metal, and at least one reactive surface within the vessel coupled to a power source. A method for removing a component from a gaseous mixture is provided comprising exposing the gaseous mixture to a fluid containing a ligand and a reactive metal, the exposing chemically binding the component of the gaseous mixture to the ligand. A method of capturing a component of a gaseous mixture is provided comprising: exposing the gaseous mixture to a fluid containing a ligand and a reactive metal, the exposing chemically binding the component of the gaseous mixture to the ligand, altering the oxidation state of the metal, the altering unbinding the component from the ligand, and capturing the component.

  10. The impact of air-fuel mixture composition on SI engine performance during natural gas and producer gas combustion

    Science.gov (United States)

    Przybyła, G.; Postrzednik, S.; Żmudka, Z.

    2016-09-01

    The paper summarizers results of experimental tests of SI engine fuelled with gaseous fuels such as, natural gas and three mixtures of producer gas substitute that simulated real producer gas composition. The engine was operated under full open throttle and charged with different air-fuel mixture composition (changed value of air excess ratio). The spark timing was adjusted to obtain maximum brake torque (MBT) for each fuel and air-fuel mixture. This paper reports engine indicated performance based on in-cylinder, cycle resolved pressure measurements. The engine performance utilizing producer gas in terms of indicated efficiency is increased by about 2 percentage points when compared to fuelling with natural gas. The engine power de-rating when producer gas is utilized instead the natural gas, varies from 24% to 28,6% under stoichiometric combustion conditions. For lean burn (λ=1.5) the difference are lower and varies from 22% to 24.5%.

  11. Oxygen/ozone as a medical gas mixture. A critical evaluation of the various methods clarifies positive and negative aspects

    Directory of Open Access Journals (Sweden)

    Bocci Velio

    2011-04-01

    Full Text Available Abstract Besides oxygen, several other gases such as NO, CO, H2, H2S, Xe and O3 have come to age over the past few years. With regards to O3, its mechanisms of action in medicine have been clarified during the last two decades so that now a comprehensive framework for understanding and recommending ozone therapy in various pathologies is available. O3 used within the determined therapeutic window is absolutely safe and more effective than golden standard medications in numerous pathologies, like vascular diseases. However, ozone therapy is mostly in practitioners' hands and some recent developments for increasing cost effectiveness and speed of treatment are neither standardized, nor evaluated toxicologically. Hence, the aim of this article is to emphasize the need to objectively assess the pros and cons of oxygen/ozone as a medical gas mixture in the hope that ozone therapy will be accepted by orthodox medicine in the near future.

  12. Research of the DC discharge of He-Ne gas mixture in hollow core fiber

    Science.gov (United States)

    Wang, Xinbing; Duan, Lian

    2013-09-01

    Since the first waveguide 0.633 μm He-Ne laser from a 20 cm length of 430 μm glass capillary was reported in 1971, no smaller waveguide gas laser has ever been constructed. Recently as the development of low loss hollow core PBG fiber, it is possible to constract a He-Ne lasers based on hollow-core PBG fibers. For the small diameter of the air hole, it is necessary to do some research to obtain glow discharge in hollow core fibers. In this paper, the experimental research of DC discharge in 200 μm bore diameter hollow core fibers was reported. Stable glow discharge was obained at varioue He-Ne mixtures from 4 Torr to 18 Torr. In order to obtain the plasma parameter of the discharge, the trace gasses of N2 and H2 were added to the He-Ne mixtures, the optical emission spectroscopy of the discharge was recorded by a PI 2750 spectroscopy with a CCD camera. The gas temperature (Tg) could be obtained by matching the simulated rovibronic band of the N2 emission with the observed spectrum in the ultraviolet region. The spectral method was also used to obtained the electron density, which is based on the analysis of the wavelength profile of the 486.13 nm Hβ line, and the electron temperature was obtain by Boltzmann plot methods. Experimental results show that it is very difficult to achieve DC discharge in bore diameter less than 50 μm, and a RF discharge method was proposed. Project supported by the National Natural Science Foundation of China (61078033).

  13. Dependence of composition of stable molecules in N2-H2 plasmas on nitrogen gas flow rate ratio measured using a quartz sensor

    Science.gov (United States)

    Suzuki, Atsushi; Asahina, Shuichi

    2014-11-01

    Compositions of stable molecules in N2-H2 plasmas measured using a quartz sensor (Q-sensor) were compared with those measured using a quadrupole mass spectrometer (QMS) under various nitrogen gas flow rate ratio to determine the applicability of Q-sensor measurement to N2-H2 plasmas. The nitrogen flow rate ratio dependence of the Q-sensor results obtained 20 mm from the edge of the plasma electrodes (Z = 20 mm) tended to agree more qualitatively with the NH3 density measured by QMS compared with those measured at 70 mm. For pure nitrogen or hydrogen plasma, the results measured at Z = 20 mm differed from those of gas analyses using QMS. The analysis indicated that Q-sensor results obtained near discharges with various nitrogen flow rate ratios reflect information on stable molecules such as N2, H2, and NH3 but yield information on other stable molecules or other chemical species in pure N2 and H2 plasmas.

  14. Metal–organic frameworks to satisfy gas upgrading demands: fine-tuning the soc-MOF platform for the operative removal of H2S

    KAUST Repository

    Belmabkhout, Youssef

    2017-01-06

    A cooperative experimental/modeling strategy was used to unveil the structure/gas separation performance relationship for a series of isostructural metal-organic frameworks (MOFs) with soc-topology (square-octahedral) hosting different extra-framework counter ions (NO3-, Cl- and Br-). In3+-, Fe3+-, Ga3+-and the newly isolated Al(III)-based isostructural soc-MOF were extensively studied and evaluated for the separation-based production of high-quality fuels (i.e., CH4, C3H8 and n-C4H10) and olefins. The structural/chemical fine-tuning of the soc-MOF platform promoted equilibrium-based selectivity toward C2+ (C2H6, C2H4, C3H6 C3H8 and n-C4H10) and conferred the desired chemical stability toward H2S. The noted dual chemical stability and gas/vapor selectivity, which have rarely been reported for equilibrium-based separation agents, are essential for the production of high-purity H-2, CH4 and C2+ fractions in high yields. Interestingly, the evaluated soc-MOF analogues exhibited high selectivity for C2H4, C3H6 and n-C4H10. In particular, the Fe, Ga and Al analogues presented relatively enhanced C2+/CH4 adsorption selectivities. Notably, the Ga and Al analogues were found to be technically preferable because their structural integrities and separation performances were maintained upon exposure to H2S, indicating that these materials are highly tolerant to H2S. Therefore, the Ga-soc-MOF was further examined for the selective adsorption of H2S in the presence of CO2-and CH4-containing streams, such as refinery-off gases (ROG) and natural gas (NG). Grand canonical Monte Carlo (GCMC) simulations based on a specific force field describing the interactions between the guest molecules and the Ga sites supported and confirmed the considerably higher affinity of the Ga-soc-MOF for C2+ (as exemplified by n-C4H10) than for CH4. The careful selection of an appropriate metal for the trinuclear inorganic molecular building block (MBB), i. e., a Ga metal center, imbues the soc

  15. Pure SF6 and SF6-N2 mixture gas hydrates equilibrium and kinetic characteristics.

    Science.gov (United States)

    Lee, Eun Kyung; Lee, Ju Dong; Lee, Hyun Ju; Lee, Bo Ram; Lee, Yoon Seok; Kim, Soo Min; Park, Hye Ok; Kim, Young Seok; Park, Yeong-Do; Kim, Yang Do

    2009-10-15

    Sulfur hexafluoride (SF6), whether pure or mixed with inexpensive inert gas, has been widely used in a variety of industrial processes, but it is one of the most potent greenhouse gases. For this reason, it is necessary to separate and/or collect it from waste gas streams. In this study, we investigated the pure SF6 and SF6-N2 mixture gas hydrates formation equilibrium aswell asthe gas separation efficiency in the hydrate process. The equilibrium pressure of SF6-N2 mixture gas was higher than that of pure SF6 gas. Phase equilibrium data of SF6-N2 mixture gas was similar to SF6 rather than N2. The kinetics of SF6-N2 mixture gas was controlled by the amount of SF6 at the initial gas composition as well as N2 gas incorporation into the S-cage of structure-II hydrate preformed by the SF6 gas. Raman analysis confirmed the N2 gas incorporation into the S-cage of structure-II hydrate. The compositions in the hydrate phase were found to be 71, 79, 80, and 81% of SF6 when the feed gas compositions were 40, 65, 70, and 73% of SF6, respectively. The present study provides basic information for the separation and purification of SF6 from mixed SF6 gas containing inert gases.

  16. Inflowing gas onto a compact obscured nucleus in Arp 299A: Herschel spectroscopic studies of H2O and OH

    CERN Document Server

    Falstad, N; Aalto, S; Fischer, J

    2016-01-01

    Aims. We probe the physical conditions in the core of Arp 299A and try to put constraints to the nature of its nuclear power source. Methods. We used Herschel Space Observatory far-infrared and submillimeter observations of H2O and OH rotational lines in Arp 299A to create a multi-component model of the galaxy. In doing this, we employed a spherically symmetric radiative transfer code. Results. Nine H2O lines in absorption and eight in emission as well as four OH doublets in absorption and one in emission, are detected in Arp 299A. No lines of the 18O isotopologues, which have been seen in compact obscured nuclei of other galaxies, are detected. The absorption in the ground state OH doublet at 119 {\\mu}m is found redshifted by ~175 km/s compared to other OH and H2O lines, suggesting a low excitation inflow. We find that at least two components are required in order to account for the excited molecular line spectrum. The inner component has a radius of 20-25 pc, a very high infrared surface brightness (> 3e13 ...

  17. Fiber-Amplifier-Enhanced QEPAS Sensor for Simultaneous Trace Gas Detection of NH3 and H2S

    Directory of Open Access Journals (Sweden)

    Hongpeng Wu

    2015-10-01

    Full Text Available A selective and sensitive quartz enhanced photoacoustic spectroscopy (QEPAS sensor, employing an erbium-doped fiber amplifier (EDFA, and a distributed feedback (DFB laser operating at 1582 nm was demonstrated for simultaneous detection of ammonia (NH3 and hydrogen sulfide (H2S. Two interference-free absorption lines located at 6322.45 cm−1 and 6328.88 cm−1 for NH3 and H2S detection, respectively, were identified. The sensor was optimized in terms of current modulation depth for both of the two target gases. An electrical modulation cancellation unit was equipped to suppress the background noise caused by the stray light. An Allan-Werle variance analysis was performed to investigate the long-term performance of the fiber-amplifier-enhanced QEPAS sensor. Benefitting from the high power boosted by the EDFA, a detection sensitivity (1σ of 52 parts per billion by volume (ppbv and 17 ppbv for NH3 and H2S, respectively, were achieved with a 132 s data acquisition time at atmospheric pressure and room temperature.

  18. Solution and Diffusion Behavior of Pure Gases and Gas Mixtures in Glassy Polymer Membranes

    Institute of Scientific and Technical Information of China (English)

    庄震万; 卫伟; 时钧

    1994-01-01

    A general model for the solution and diffusion behavior in pure gas-polymer membrane systems and gas mixture-polymer membrane systems has been developed. Proved by experiments on different glassy and rubbery polymer membranes at various temperatures and pressures, this model can achieve the prediction of permeation behavior of pure gases and gas mixtures in polymer membranes only using the model parameters obtained from experiments on pure gases. The calculated results are in good agreement with experimental.

  19. Inflowing gas onto a compact obscured nucleus in Arp 299A. Herschel spectroscopic studies of H2O and OH

    Science.gov (United States)

    Falstad, N.; González-Alfonso, E.; Aalto, S.; Fischer, J.

    2017-01-01

    Aims: We probe the physical conditions in the core of Arp 299A and try to put constraints on the nature of its nuclear power source. Methods: We used Herschel Space Observatory far-infrared and submillimeter observations of H2O and OH rotational lines in Arp 299A to create a multi-component model of the galaxy. In doing this, we employed a spherically symmetric radiative transfer code. Results: Nine H2O lines in absorption and eight in emission, as well as four OH doublets in absorption and one in emission, are detected in Arp 299A. No lines of the 18O isotopologues, which have been seen in compact obscured nuclei of other galaxies, are detected. The absorption in the ground state OH 2Π3/2-2Π3/2(5/2)+-(3/2)- doublet at 119 μm is found redshifted by 175 km s-1 compared with other OH and H2O lines, suggesting a low excitation inflow. We find that at least two components are required in order to account for the excited molecular line spectrum. The inner component has a radius of 20-25 pc, a very high infrared surface brightness (≳3 × 1013L⊙kpc-2), warm dust (Td > 90 K), and a large H2 column density (NH2 > 1024 cm-2). The modeling also indicates high nuclear H2O (1-5 × 10-6) and OH (0.5-5 × 10-5) abundances relative to H nuclei. The outer component is larger (50-100 pc) with slightly cooler dust (70-90 K) and molecular abundances that are approximately one order of magnitude lower. In addition to the two components that account for the excited OH and H2O lines, we require a much more extended inflowing component to account for the OH 2Π3/2-2Π3/2(5/2)+-(3/2)- doublet at 119 μm. Conclusions: The Compton-thick nature of the core makes it difficult to determine the nature of the buried power source, but the high surface brightness indicates that it is an active galactic nucleus and/or a dense nuclear starburst. Our results are consistent with a composite source. The high OH/H2O ratio in the nucleus indicates that ion-neutral chemistry induced by X-rays or

  20. c2d Spitzer IRS Spectra of Disks around T Tauri Stars. III. [Ne II], [Fe I], and H_2 gas-phase lines

    CERN Document Server

    Lahuis, Fred; Blake, Geoffrey A; Evans, Neal J; Kessler-Silacci, Jacqueline E; Pontoppidan, Klaus M

    2007-01-01

    We present a survey of mid-infrared gas-phase lines toward a sample of 76 circumstellar disks around low mass pre-main sequence stars from the Spitzer "Cores to Disks" legacy program. We report the first detections of [Ne II] and [Fe I] toward classical T Tauri stars in ~20% respectively ~9% of our sources. The observed [Ne II] line fluxes and upper limits are consistent with [Ne II] excitation in an X-ray irradiated disk around stars with X-ray luminosities L_X=10^{29}-10^{31} erg s^{-1}. [Fe I] is detected at ~10^-5-10^-4 L_Sun, but no [S I] or [Fe II] is detected down to ~10^{-6} L_Sun. The [Fe I] detections indicate the presence of gas-rich disks with masses of >~0.1 M_J. No H_2 0-0 S(0) and S(1) disk emission is detected, except for S(1) toward one source. These data give upper limits on the warm (T~100-200K) gas mass of a few Jovian masses, consistent with recent T Tauri disk models which include gas heating by stellar radiation. Compact disk emission of hot (T>~500K) gas is observed through the H_2 0-0...

  1. Effect of thickness on nanostructured SnO2 thin films by spray pyrolysis as highly sensitive H2S gas sensor.

    Science.gov (United States)

    Patil, G E; Kajale, D D; Gaikwad, V B; Jain, G H

    2012-08-01

    Nanostructured SnO2 thin films were prepared by spray pyrolysis technique onto glass substrates with different thickness by varying quantity of precursor solution. The structural, optical and electrical properties of these films have been studied. The crystallographic structure of the films was studied by X-ray diffraction (XRD). It is found that the films are tetragonal with (110) orientation. The grain size increases with thickness. Atomic Force Microscopy (AFM) showed that the nanocrystalline nature of the films with porous nature. The grain size increased 14 to 29 nm with increase in film thickness. The studies on the optical properties show that the direct band gap value decreases from 3.75 to 3.50 eV. The temperature dependence of the electrical conductivity was studied. The activation energies of the films are calculated from the conductance temperature characteristics. The nanostructured SnO2 thin films were used as sensing layers for resistive gas sensors. The dependence of gas sensing properties on the thickness of SnO2 thin films was investigated. The gas response of the SnO2 thin films towards the H2S gas was determined at an operating temperature of 150 degrees C. The sensitivity towards H2S gas is strongly depending on surface morphology of the SnO2 thin films.

  2. 49 CFR 173.305 - Charging of cylinders with a mixture of compressed gas and other material.

    Science.gov (United States)

    2010-10-01

    ... nonflammable mixtures. Mixtures containing compressed gas or gases including insecticides, which mixtures are... relief devices of a type examined by the Bureau of Explosives and approved by the Associate...

  3. Modelling of associating mixtures for applications in the oil & gas and chemical industries

    DEFF Research Database (Denmark)

    Kontogeorgis, Georgios; Folas, Georgios; Muro Sunè, Nuria

    2007-01-01

    -alcohol (glycol)-alkanes and certain acid and amine-containing mixtures. Recent results include glycol-aromatic hydrocarbons including multiphase, multicomponent equilibria and gas hydrate calculations in combination with the van der Waals-Platteeuw model. This article will outline some new applications...... of the model of relevance to the petroleum and chemical industries: high pressure vapor-liquid and liquid-liquid equilibrium in alcohol-containing mixtures, mixtures with gas hydrate inhibitors and mixtures with polar and hydrogen bonding chemicals including organic acids. Some comparisons with conventional...

  4. A study of Zn-Mn based sorbent for the high-temperature removal of H2S from coal-derived gas.

    Science.gov (United States)

    Ko, Tzu-Hsing; Chu, Hsin; Liou, Ya-Jing

    2007-08-17

    Zn-Mn based sorbents supported on SiO2, gamma-Al(2)O(3) and ZrO2, prepared by the incipient wetness impregnation method with calcination at 973 K were investigated for the removal of H(2)S from coal derived gas at the temperature ranges of 773-973 K. Results reveal that the SiO2 and ZrO2 supports exhibit the better performance because better removal efficiency. The addition of manganese effectually improves the vaporization of zinc. In addition, some operating parameters were also considered in order to understand as well as screen the suitable conditions for the development of Zn-Mn based sorbents on the removal of H(2)S. Over 98% sorbent utilization was established for the use of SiO2 at 873 K. On the other hand, within the 5-15 wt% of Zn-Mn oxides, no significant change in the sorbent utilization was observed. Up to 30 wt% the sorbent utilization decreased slightly compared to lower contents, which may be attributed to the deficient dispersion. With increasing the H2 concentration, the sorbent utilization decreases and an adverse result is observed in the case of increasing CO concentration. The relationship between CO and H2 could be explained via the water-gas shift reaction. Moreover, the apparent activation energy and frequency factor as well as the predicted results were studied with a deactivation model. The results of regression fitting reveal the accurate prediction breakthrough behaviors for the removal of H(2)S.

  5. H2S/N2混合物在碳纳米管中吸附分离的分子模拟%Molecular Simulations of Adsorption and Separation of H2S and N2 Mixture by Single Wall Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    乔智威; 任树化; 周健

    2012-01-01

    Adsorption and separation of 1 : 99(volume ratio) HjS/N, mixture by single wall carbon nanotubes were studied using the grand canonical Monte Carlo(GCMC) method at a range of nanotube diameters, pressures and temperatures. It is demonstrated that the selectivity towards H2S increases and then decreases with increasing nanotube diameter and the selectivity is highest for (11,0) carbon nanotube which is due to the synergy of geometry effect and energy effect. It is shown that under different operation conditions, the adsorption isotherm and selectivity can vary significantly. At 100 kPa, the amount of adsorbed of H2S in (11,0) carbon nanotube and the selectivity towards H2S firstly increase and then decrease with increasing temperatures. Moreover, at 300 K, with increasing pressures, the adsorbed amount of H2S and the selectivity towards H2S decrease. The simulation findings in this work would be helpful for the design and development of sulfur removal processes.%采用巨正则Monte Carlo(GCMC)方法讨论了不同温度、压力及管径下,碳纳米管对H2S/N2混合物(主体相体积比为1:99)的吸附分离选择性.结果表明,随着碳纳米管管径的增大,H2S的吸附选择性先增加后减小;而(11,0)碳纳米管(管径为0.86 nm)对H2S的选择性最高,这种选择性与管径的关系是由几何效应和能量效应共同决定的.针对(11,0)碳纳米管讨论了温度和压力对H2S吸附量和选择性的影响.模拟结果表明,随着温度上升,H2S的吸附量和选择性都呈先增加后减小的趋势;随着压力增加,H2S的吸附量和选择性都有所下降.本文模拟结果可为含硫气体混合物的吸附分离提供一定参考.

  6. First accurate experimental study of Mu reactivity from a state-selected reactant in the gas phase: the Mu + H2{1} reaction rate at 300 K

    Science.gov (United States)

    Bakule, Pavel; Sukhorukov, Oleksandr; Ishida, Katsuhiko; Pratt, Francis; Fleming, Donald; Momose, Takamasa; Matsuda, Yasuyuki; Torikai, Eiko

    2015-02-01

    This paper reports on the experimental background and methodology leading to recent results on the first accurate measurement of the reaction rate of the muonium (Mu) atom from a state-selected reactant in the gas phase: the Mu + H2\\{1\\}\\to MuH + H reaction at 300 K, and its comparison with rigorous quantum rate theory, Bakule et al (2012 J. Phys. Chem. Lett. 3 2755). Stimulated Raman pumping, induced by 532 nm light from the 2nd harmonic of a Nd:YAG laser, was used to produce H2 in its first vibrational (v = 1) state, H2\\{1\\}, in a single Raman/reaction cell. A pulsed muon beam (from ‘ISIS’, at 50 Hz) matched the 25 Hz repetition rate of the laser, allowing data taking in equal ‘Laser-On/Laser-Off’ modes of operation. The signal to noise was improved by over an order of magnitude in comparison with an earlier proof-of-principle experiment. The success of the present experiment also relied on optimizing the overlap of the laser profile with the extended stopping distribution of the muon beam at 50 bar H2 pressure, in which Monte Carlo simulations played a central role. The rate constant, found from the analysis of three separate measurements, which includes a correction for the loss of {{H}2}\\{1\\} concentration due to collisional relaxation with unpumped H2 during the time of each measurement, is {{k}Mu}\\{1\\} = 9.9[(-1.4)(+1.7)] × 10-13 cm3 s-1 at 300 K. This is in good to excellent agreement with rigorous quantum rate calculations on the complete configuration interaction/Born-Huang surface, as reported earlier by Bakule et al, and which are also briefly commented on herein.

  7. Laboratory studies of thermally processed H2O-CH3OH-CO2 ice mixtures and their astrophysical implications

    NARCIS (Netherlands)

    Ehrenfreund, P; Kerkhof, O; Schutte, WA; Boogert, ACA; Gerakines, PA; Dartois, E; d'Hendecourt, L; Tielens, AGGM; van Dishoeck, EF; Whittet, DCB

    1999-01-01

    Data of the Infrared Space Observatory ISO have strongly influenced the current view of interstellar ice chemistry. ISO and ground-based results have confirmed that the most abundant ice species in warm regions close to massive protostars are H2O, CO2, and CH3OH. Ice segregation in those environment

  8. 油气开采中H2S腐蚀的影响因素研究%Research on Impact Factors of H2S Corrosion in Oil & Gas Production

    Institute of Scientific and Technical Information of China (English)

    熊颖; 陈大钧; 王君; 张启根

    2007-01-01

    文章介绍了油气开采过程中H2S腐蚀的主要形式、腐蚀特征和影响因素.影响H2S腐蚀的主要因素有:材质因素和包括H2S质量浓度、温度、H2S分压、pH值和流速等在内的环境因素.对今后关于油气开采过程中的H2S腐蚀研究方面提出了建议:加强H2S的腐蚀机理和影响因素研究,特别是要深入研究多种影响因素共存条件下对H2S腐蚀行为的影响.

  9. Enhanced selective extraction of hexane from hexane/soybean oil mixture using binary gas mixtures of carbon dioxide.

    Science.gov (United States)

    Eller, Fred J; Taylor, S L; Palmquist, Debra E

    2007-04-18

    Carbon dioxide (CO2) can effectively separate hexane from a mixture of soybean oil (SBO) and hexane with a slight coextraction of SBO. Previous research demonstrated that CO2 entrained with helium significantly reduced SBO solubility in CO2. In this study, CO2 was mixed with three gases (He, N2, or Ar) (0.5-30 vol %) to decrease SBO solubility while attempting to maintain hexane solubility. The binary gas mixtures (at 25 degrees C and 9.31 MPa) were passed through a 25 wt % hexane/SBO mixture inside a 2.5 m fractionation column. Coextracted SBO was inversely proportional to binary gas concentration, whereas residual hexane in the raffinate was proportional to binary gas concentration. The 10% binary mixture of N2 or Ar was the best compromise to obtain both low residual hexane levels (i.e., 26 ppm) and low SBO coextraction (i.e., only 40 mg). This carry-over of SBO represents a 95% reduction in SBO carry-over compared to neat CO2.

  10. H2S-mediated thermal and photochemical methane activation.

    Science.gov (United States)

    Baltrusaitis, Jonas; de Graaf, Coen; Broer, Ria; Patterson, Eric V

    2013-12-02

    Sustainable, low-temperature methods for natural gas activation are critical in addressing current and foreseeable energy and hydrocarbon feedstock needs. Large portions of natural gas resources are still too expensive to process due to their high content of hydrogen sulfide gas (H2S) mixed with methane, deemed altogether as sub-quality or "sour" gas. We propose a unique method of activation to form a mixture of sulfur-containing hydrocarbon intermediates, CH3SH and CH3SCH3 , and an energy carrier such as H2. For this purpose, we investigated the H2S-mediated methane activation to form a reactive CH3SH species by means of direct photolysis of sub-quality natural gas. Photoexcitation of hydrogen sulfide in the CH4 + H2S complex resulted in a barrierless relaxation by a conical intersection to form a ground-state CH3SH + H2 complex. The resulting CH3SH could further be coupled over acidic catalysts to form higher hydrocarbons, and the resulting H2 used as a fuel. This process is very different from conventional thermal or radical-based processes and can be driven photolytically at low temperatures, with enhanced control over the conditions currently used in industrial oxidative natural gas activation. Finally, the proposed process is CO2 neutral, as opposed to the current industrial steam methane reforming (SMR).

  11. Influence of impurities in CO{sub 2}-rich gas mixtures on the storage capacity of mature natural gas fields

    Energy Technology Data Exchange (ETDEWEB)

    Schoeneich, S.; May, F.; Vosteen, H.D. [Bundesanstalt fuer Geowissenschaften und Rohstoffe, Hannover (Germany)

    2007-09-13

    The carbon dioxide concentrations of a storage gas range in general between 90-95 % after the CO{sub 2} separation in the power plant process. An Oxyfuel lignite fired power plant provides a CO{sub 2}-rich gas mixture with impurities basically consisting of N{sub 2}, O{sub 2}, Ar, SO{sub 2}, CO and H{sub 2}O. The minor components affect the storage capacity in mature natural gas fields. They reduce the density of the gas mixture. In a storage depth of 1 km and 3 km, 5 mole% N{sub 2} lead to a reduction of the storage capacity of 22 % and 9 %, respectively. A 10 billion m{sup 3} volume of methane is equivalent to a storage capacity of 53 million tons (Mt) of pure CO{sub 2} under common storage conditions of 316 K and 12.1 MPa in 1 km depth. If the CO{sub 2} gas mixture contains 5 % N{sub 2}, the same storage volume takes only 41 Mt of CO{sub 2}. Process-related minor components in a CO{sub 2}-rich gas and the mixture with residual gases in the mature gas fields (shown exemplarily for one natural gas field) should be considered in estimates of storage capacities in natural gas fields. (orig.)

  12. Effect of gas phase composition cycling on/off modulation numbers of C2H2/SF6 flows on the formation of geometrically controlled carbon coils.

    Science.gov (United States)

    Eum, Jun-Ho; Jeon, Young-Chul; Kim, Sung-Hoon

    2012-07-01

    Carbon coils can be synthesized using C2H2/H2 as source gases and SF6 as an incorporated additive gas under a thermal chemical vapor deposition system. In this study, nickel catalyst layer deposition and then hydrogen plasma pretreatment were performed prior to the carbon coils deposition reaction. To obtain geometrically controlled carbon coils, source gases and SF6 were manipulated as the cycling on/off modulation numbers of C2H2/SF6 flows. The cycling numbers were varied according to the different reaction processes. The increased cycling numbers could develop the wave-like nano-sized carbon coils. By further increasing the cycling numbers, however, the nanostructured carbon coils seemed to deteriorate. As a result, the maximum formation of geometrically controlled carbon coils was achieved by adjusting the cycling numbers. The enhanced etching capability of the fluorine-related species in SF6 additive gas was considered for the main objective of controlling the geometry of carbon coils.

  13. CO/H$_2$, C/CO, OH/CO, and OH/O$_2$ in Dense Interstellar Gas: From High Ionization to Low Metallicity

    CERN Document Server

    Bialy, Shmuel

    2014-01-01

    We present numerical computations and analytic scaling relations for cold-gas, ionization-driven interstellar ion-molecule chemistry, down to the very low metallicities (< 10$^{-3}$ solar) associated with the Pop-III to Pop-II star transition and the early enrichment reionization epoch. We focus on the behavior for H$_2$, CO, CH, OH, H$_2$O and O$_2$. We consider shielded or partially shielded one-zone gas parcels, and solve the chemical rate equations for steady-state conditions for a wide range of ionization parameters, $\\zeta/n$, and metallicties, $Z'$. We find that the OH abundances are always maximal at the H-to-H$_2$ conversion points, and that large OH abundances persist at very low metallicities even when the hydrogen is predominantly atomic. We study the OH/O$_2$, C/CO and OH/CO abundance ratios, from large to small, as functions of $\\zeta/n$ and $Z'$. Cold dense star-forming clouds for the Pop-II generation may have been OH-dominated and atomic rather than CO-dominated and molecular.

  14. Modeling mass transfer in solid oxide fuel cell anode: II. H2/CO co-oxidation and surface diffusion in synthesis-gas operation

    Science.gov (United States)

    Bao, Cheng; Jiang, Zeyi; Zhang, Xinxin

    2016-08-01

    Following the previous work on comparing performance of Fickian, Stefan-Maxwell and dusty-gas model for mass transfer in single fuel system, this article is focused on the electrochemistry and transport in the anode of solid oxide fuel cell using H2sbnd H2Osbnd COsbnd CO2sbnd N2 hybrid fuel. Under the standard framework of the dusty-gas model combined with the Butler-Volmer equation, it carries out a macroscopic area-specific modeling work. More specifically, two variables of hydrogen current fraction and enhancement factor are well defined and solved for the electrochemical co-oxidation of H2 and CO, and the diffusion equivalent circuit model is introduced to describe more comprehensively the resistance of mass transfer including molecular/Knudsen diffusion and surface diffusion. The model has been validated well in full region of Vsbnd I performance of an experimental anode-supported button cell. An approximate analytical solution of the hydrogen current fraction is also presented for explicit computation. Comparison between the results by different approaches for the effective diffusivity shows the importance of right mass-transfer modeling.

  15. 气相分解硫化氢制氢的实验探索%The Experiment Discussion on the Decomposition of H2S in Gas Phase to Produce H2

    Institute of Scientific and Technical Information of China (English)

    付晓红

    2011-01-01

    采用波长为253.7nm的紫外光为光源,以Na2S溶液为反应液,进行了紫外光气相法分解硫化氢(H2S)制氢反应.考察了H2S通入流量、连续分解硫化氢、不同浓度的H2S、光催化分解H2S及气相分解与液相分解H2S的对比对产氢量的影响.研究结果表明,连续向反应液中通入H2S可以提高产氢量;气相直接分解H2S时,H2S分解的速度和其浓度成正比;气相分解H2S的反应在H2S浓度很高时比液相反应的效率高,在低浓度时,反应效率低于液相反应.

  16. Computational study of the I2O5 + H2O = 2 HOIO2 gas-phase reaction

    Science.gov (United States)

    Khanniche, Sarah; Louis, Florent; Cantrel, Laurent; Černušák, Ivan

    2016-10-01

    This paper presents the mechanism and the kinetics of the I2O5 (g) + H2O (g) = 2 HOIO2 (g) reaction. The potential energy surface was explored with the B3LYP and MP2 methods with the aug-cc-pVTZ basis set. The rate constants were computed as a function of temperature (250-750 K) using transition state theory. At the CCSD(T)/CBS level, the rate constants were estimated to be: (k in cm3 molecule-1 s-1) kforward(T) = 3.61 × 10-22 × T2.05 exp (-32.3 (kJ mol-1)/RT) and kreverse (T) = 6.73 × 10-27 × T2.90 exp (-24.5 (kJ mol-1)/RT). Implications for atmospheric chemistry and nuclear safety issues are discussed.

  17. Proportional counters aged anode wire recovering using an 80%CF4 + 20%CO2 gas mixture

    CERN Document Server

    Gavrilov, Gennady; Conti, Richard; Fetisov, Andrey; Maysuzenko, Dmitry; Shvecova, Natalia; Vakhtel, Victor

    2011-01-01

    A technique to recover a gas proportional counter having an aged anode wire using a glow discharge in an 80%CF4 + 20%CO2 gas mixture has been developed and tested. Studies of aging effects were carried out under sustained irradiation by an intense 90Sr -source of the straw proportional counters operated with a 60%Ar + 30%CO2 + 10%CF4 gas mixture. Special attention was paid to the aging mechanism of the anode wires. Our experience showed that using a given gas mixture the swelling of the anode wires is a typical mode of aging that leads to degradation of the gas gain. The proposed method of recovery provided a complete restoration of the gas gain and the signal amplitude in the damaged zone of the wire. SEM/XEM analysis confirmed successful cleaning WOx deposits from the wire surface. The application of this method to recover the aged gaseous detectors in real experimental conditions is discussed.

  18. Disposable, Paper-Based, Inkjet-Printed Humidity and H2S Gas Sensor for Passive Sensing Applications

    KAUST Repository

    Quddious, Abdul

    2016-12-06

    An inkjet-printed, fully passive sensor capable of either humidity or gas sensing is presented herein. The sensor is composed of an interdigitated electrode, a customized printable gas sensitive ink and a specialized dipole antenna for wireless sensing. The interdigitated electrode printed on a paper substrate provides the base conductivity that varies during the sensing process. Aided by the porous nature of the substrate, a change in relative humidity from 18% to 88% decreases the electrode resistance from a few Mega-ohms to the kilo-ohm range. For gas sensing, an additional copper acetate-based customized ink is printed on top of the electrode, which, upon reaction with hydrogen sulphide gas (HS) changes, both the optical and the electrical properties of the electrode. A fast response time of 3 min is achieved at room temperature for a HS concentration of 10 ppm at a relative humidity (RH) of 45%. The passive wireless sensing is enabled through an antenna in which the inner loop takes care of conductivity changes in the 4-5 GHz band, whereas the outer-dipole arm is used for chipless identification in the 2-3 GHz band.

  19. Effect of noble gas mixtures on the performance of regenerative-type cryocoolers analytical estimate

    Science.gov (United States)

    Daney, D. E.

    1990-09-01

    The performance of regenerators that use noble gas mixtures is compared to the performance of those that use pure helium gas. Both helium-argon and helium-krypton mixtures are investigated. For some heat transfer surfaces, a modest gain in heat transfer can be achieved with these mixtures. The concomitant increase in pressure drop, however, more than offsets the heat transfer gain so the net regenerator loss increases for all evaluated cases. The dependence of heat transfer on Prandtl number (Pr) was not measured for the range associated with noble gas mixtures, 0.2 less than Pr less than 0.5, and it is estimated that the uncertainty from the source can exceed 20 percent. The estimates for the transport properties (Prandtl number, viscosity, and thermal conductivity) of helium-argon and helium-krypton mixtures because of the absence of experimental data at low temperature are given.

  20. Gas-Solid Reaction Route toward the Production of Intermetallics from Their Corresponding Oxide Mixtures

    Directory of Open Access Journals (Sweden)

    Hesham Ahmed

    2016-08-01

    Full Text Available Near-net shape forming of metallic components from metallic powders produced in situ from reduction of corresponding pure metal oxides has not been explored to a large extent. Such a process can be probably termed in short as the “Reduction-Sintering” process. This methodology can be especially effective in producing components containing refractory metals. Additionally, in situ production of metallic powder from complex oxides containing more than one metallic element may result in in situ alloying during reduction, possibly at lower temperatures. With this motivation, in situ reduction of complex oxides mixtures containing more than one metallic element has been investigated intensively over a period of years in the department of materials science, KTH, Sweden. This review highlights the most important features of that investigation. The investigation includes not only synthesis of intermetallics and refractory metals using the gas solid reaction route but also study the reaction kinetics and mechanism. Environmentally friendly gases like H2, CH4 and N2 were used for simultaneous reduction, carburization and nitridation, respectively. Different techniques have been utilized. A thermogravimetric analyzer was used to accurately control the process conditions and obtain reaction kinetics. The fluidized bed technique has been utilized to study the possibility of bulk production of intermetallics compared to milligrams in TGA. Carburization and nitridation of nascent formed intermetallics were successfully carried out. A novel method based on material thermal property was explored to track the reaction progress and estimate the reaction kinetics. This method implies the dynamic measure of thermal diffusivity using laser flash method. These efforts end up with a successful preparation of nanograined intermetallics like Fe-Mo and Ni-W. In addition, it ends up with simultaneous reduction and synthesis of Ni-WN and Ni-WC from their oxide mixtures

  1. Synthesis of electrocatalysts by the Bönnemann method for the oxidation of methanol and the mixture H2/CO in a Proton Exchange Membrane Fuel Cell

    Directory of Open Access Journals (Sweden)

    Franco E. G.

    2002-01-01

    Full Text Available The synthesis of ternary electrocatalysts Pt/Ru/Mo type were performed according to the Bönnemann method and characterized by the following techniques: energy dispersive analysis (EDX, X-rays diffraction (XRD, cyclic voltammetry (CV and polarization curves (E vs. i for the oxidation of H2, H2/CO and methanol in a Proton Exchange Membrane Fuel Cell (PEMFC. Catalysts structure consists of highly dispersed nanocrystals in carbon support, with an average particle size of 2 nm. The results of cyclic voltammetry suggest an enhancement of the catalyst electroactivity with the addition of cocatalysts. Polarization curves indicate that Pt/Ru/Mo systems could be employed as electrode material for PEM fuel cell for technological application.

  2. Electron transport coefficients in the mixtures of H2O with N2, O2, CO2 and dry air for the optimization of non-thermal atmospheric pressure plasmas

    Science.gov (United States)

    Ruíz-Vargas, G.; Yousfi, M.; de Urquijo, J.

    2010-11-01

    This paper presents the simultaneous measurement and calculation of the electron drift velocity in binary and ternary mixtures of N2, O2, CO2 with H2O. The main aim of this study has been the generation of a self-consistent set of validated collision cross sections that explain thoroughly the dependence of the electron drift velocity in the above pure gases and their mixtures. In doing this, changes to the collision cross section set for H2O had to be made, while all other cross section sets remained unchanged. It is worth mentioning that only a few experiments had been performed before dealing with water mixtures. The electron drift velocities in the binary and ternary mixtures under study show the effects of negative differential conductivity, and this has been explained thoroughly in terms of the collision cross sections and electron distribution functions through a multi-term Boltzmann code. It is important to note that two-term codes fail to predict the dependence of the drift velocity at low water concentrations and low E/N values. Calculated values of longitudinal and transverse diffusion coefficients, mean energies and distribution functions are also given over the E/N range 0.1 Td-2 kTd (1 Td = 10-17 V cm2).

  3. Ion mobilities in Xe/Ne and other rare-gas mixtures.

    Science.gov (United States)

    Piscitelli, D; Phelps, A V; de Urquijo, J; Basurto, E; Pitchford, L C

    2003-10-01

    The ion mobility or drift velocity data important for modeling glow discharges in rare gas mixtures are not generally available, nor are the ion-neutral scattering cross sections needed to calculate these data. In this paper we propose a set of cross sections for Xe+ and Ne+ collisions with Xe and Ne atoms. Ion mobilities at 300 K calculated using this cross section set in a Monte Carlo simulation are reported for reduced field strengths, E/N, up to 1500 x 10(-21) V m(2), in pure gases and in Xe/Ne mixtures containing 5% and 20% Xe/Ne, which are mixtures of interest for plasma display panels (PDPs). The calculated Xe+ mobilities depend strongly on the mixture composition, but the Ne+ mobility varies only slightly with increasing Xe in the mixture over the range studied here. The mobilities in pure gases compare well with available experimental values, and mobilities in gas mixtures at low E/N compare well with our recent measurements which will be published separately. Results from these calculations of ion mobilities are used to evaluate the predictions of Blanc's law and of the mixture rule proposed by Mason and Hahn [Phys. Rev. A 5, 438 (1972)] for determining the ion mobilities in mixtures from a knowledge of the mobilities in each of the pure gases. The mixture rule of Mason and Hahn is accurate to better than 10% at high field strengths over a wide range of conditions of interest for modeling PDPs. We conclude that a good estimate of ion mobilities at high E/N in Xe/Ne and other binary rare gas mixtures can be obtained using this mixture rule combined with known values of mobilities in parent gases and with the Langevin form for mobility of rare gas ions ion in other gases. This conclusion is supported by results in Ar/Ne mixtures which are also presented here.

  4. Detection of and Protection from H2S Gas on the Drlling Site%钻井现场H2S气体的探测及防护

    Institute of Scientific and Technical Information of China (English)

    王建勋

    2003-01-01

    在钻井生产过程中,实施HSE管理体系,预防和控制H2S,保护每一位员工不受H2S气体危害,是钻井生产过程中HSE工作的重要一环.阐述了有害气体H2S的物理特性、毒性标准,介绍了几种常用的H2S气体探测器,以及具体操作方法.

  5. Operation of the multigap resistive plate chamber using a gas mixture free of flammable components

    CERN Document Server

    Akindinov, A; Antonioli, P; Arcelli, S; Basile, M; Cara Romeo, G; Cifarelli, Luisa; Cindolo, F; De Caro, A; De Pasquale, S; Di Bartolomeo, A; Fusco-Girard, M; Golovine, V; Guida, M; Hatzifotiadou, D; Kaidalov, A B; Kim, D H; Kim, D W; Kisselev, S M; Laurenti, G; Lee, K; Lee, S C; Lioublev, E; Luvisetto, M L; Margotti, A; Martemyanov, A N; Nania, R; Noferini, F; Otiougova, P; Pesci, A; Pinazza, O; Polozov, P A; Scapparone, E; Scioli, G; Sellitto, S B; Semeria, F; Smirnitsky, A V; Tchoumakov, M M; Usenko, E; Valenti, G; Voloshin, K G; Williams, M C S; Zagreev, B V; Zampolli, C; Zichichi, A

    2004-01-01

    We have investigated the operation of the multigap resistive plate chamber (MRPC) for the ALICE-TOF system with a gas mixture free of flammable components. Two different gas mixtures, with and without iso-C//4H//1//0 have been used to measure the performance of the MRPC. The efficiency, time resolution, total charge, and the fast to total charge ratio have been found to be comparable.

  6. Corrosion of Inconel 690 in N2-0.1%H2S gas at 700-800 °C

    Science.gov (United States)

    Yadav, Poonam; Lee, Dong Bok

    2017-09-01

    Inconel 690 superalloy was corroded at 700 °C and 800 °C for up to 70 h in N2-0.1% H2S gas. It corroded almost linearly with large weight gains, displaying little protectiveness. Its corrosion rates were quite fast when compared with its corrosion in air or Ar-1%SO2 gas. The formed scales were thick, fragile, and nonadherent. They consisted primarily of Cr2O3 with some NiCr2O4, Ni3S2, CrS, and Cr2S3. The H2S gas accelerated the corrosion significantly by forming nonprotective sulfides and dissolving hydrogen in the scale and in the internal corrosion zone that consisted of discrete chromium-sulfides and some oxide particles. The marker test indicated that the scales grew by the outward diffusion of metallic ions such as Ni, Cr, Fe, and Mn, whilst the internal corrosion zone thickened by the inward migration of oxygen and sulfur through the lattice, grain boundaries, and microcracks.

  7. Intracavity CO laser photoacoustic trace gas detection: cyclic CH 4 , H 2 O and CO 2 emission by cockroaches and scarab beetles

    Science.gov (United States)

    Bijnen, F. G. C.; Harren, F. J. M.; Hackstein, J. H. P.; Reuss, J.

    1996-09-01

    A liquid-nitrogen-cooled CO laser and an intracavity resonant photoacoustic cell are employed to monitor trace gases. The setup was designed to monitor trace gas emissions of biological samples on line. The arrangement offers the possibility to measure gases at the 10 9 by volume (ppbv) level (e.g., CH 4 , H 2 O) and to detect rapid changes in trace gas emission. A detection limit of 1 ppbv for CH 4 in N 2 equivalent to a minimal detectable absorption of 3 10 9 cm 1 can be achieved. Because of the kinetic cooling effect we lowered the detection limit for CH 4 in air is decreased to 10 ppbv. We used the instrument in a first application to measure the CH 4 and H 2 O emission of individual cockroaches and scarab beetles. These emissions could be correlated with CO 2 emissions that were recorded simultaneously with an infrared gas analyzer. Characteristic breathing patterns of the insects could be observed; unexpectedly methane was also found to be released.

  8. A highly sensitive room temperature H2S gas sensor based on SnO2 multi-tube arrays bio-templated from insect bristles.

    Science.gov (United States)

    Tian, Junlong; Pan, Feng; Xue, Ruiyang; Zhang, Wang; Fang, Xiaotian; Liu, Qinglei; Wang, Yuhua; Zhang, Zhijian; Zhang, Di

    2015-05-07

    A tin oxide multi-tube array (SMTA) with a parallel effect was fabricated through a simple and promising method combining chemosynthesis and biomimetic techniques; a biomimetic template was derived from the bristles on the wings of the Alpine Black Swallowtail butterfly (Papilio maackii). SnO2 tubes are hollow and porous structures with micro-pores regularly distributed on the wall. The morphology, the delicate microstructure and the crystal structure of this SMTA were characterized by super resolution digital microscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The SMTA exhibits a high sensitivity to H2S gas at room temperature. It also exhibits a short response/recovery time, with an average value of 14/30 s at 5 ppm. In particular, heating is not required for the SMTA in the gas sensitivity measurement process. On the basis of these results, SMTA is proposed as a suitable new material for the design and fabrication of room-temperature H2S gas sensors.

  9. 高含硫化氢天然气气侵时的溢流特性%Overflow behaviors of natural gas kick well.with high content of H2S gas

    Institute of Scientific and Technical Information of China (English)

    孙宝江; 宋荣荣; 王志远

    2012-01-01

    以四川某高含H2S气体的气井井身结构及钻井工况为基础,针对高含H2S气井溢流时的特点,考虑H2S在水中的溶解度,建立溢流期间环空各相流体的质量和动量守恒方程,并用有限差分法对方程进行求解.结果表明:H2S在井底的溶解度远大于CH4的,在距井口约360 m开始大量析出;H2S的含量越高,气体在上升过程中密度变化越大,气体开始剧烈膨胀的位置越接近井口;井底侵入气体量相同的情况下,H2S的含量越高,气体的膨胀倍数越大,泥浆池增量也越大,同时,刚开始气侵时H2S含量越高气相的体积分数越小,而到达井口后H2S的含量越高气相的体积分数越大,导致溢流检测的难度和井控的危险程度增加;高含H2S气井溢流时井底压力的下降值、泥浆池增量、关井套压小于纯烃类的,不能反映真实的气侵程度,而且随着时间的增加情况会更严重;高含H2S气侵时压井过程中套压值与纯烃类的相差不大,因此可以在井口施加一定的压力,抑制H2S气体的膨胀,减缓井喷事故的发生.%Based on hole structure and drilling behavior of a gas well which has a high content of H2S gas in Sichuan, the conservation of mass equations and momentum equations were established considering overflow characteristics of high content of H2 S gas kick and H2 S solubility in water. And the equations were computed by using finite difference approach. The results show that the solubility of H2S is greater than that of CH4 at bottom hole, and H2S begins to separate at about 360 m a-way from wellhead. With the content of H2S increasing, the density change range increases during the gas going up, and the position of the gas dramatic expansion is close to the wellhead. When the gas kick volume is same at the bottom, the higher content of H2S, the greater gas expansion factor and pit gain, at the same time, the smaller gas volume fraction at the beginning , but greater when they

  10. Nanostructured PdO Thin Film from Langmuir-Blodgett Precursor for Room-Temperature H2 Gas Sensing.

    Science.gov (United States)

    Choudhury, Sipra; Betty, C A; Bhattacharyya, Kaustava; Saxena, Vibha; Bhattacharya, Debarati

    2016-07-01

    Nanoparticulate thin films of PdO were prepared using the Langmuir-Blodgett (LB) technique by thermal decomposition of a multilayer film of octadecylamine (ODA)-chloropalladate complex. The stable complex formation of ODA with chloropalladate ions (present in subphase) at the air-water interface was confirmed by the surface pressure-area isotherm and Brewster angle microscopy. The formation of nanocrystalline PdO thin film after thermal decomposition of as-deposited LB film was confirmed by X-ray diffraction and Raman spectroscopy. Nanocrystalline PdO thin films were further characterized by using UV-vis and X-ray photoelectron spectroscopic (XPS) measurements. The XPS study revealed the presence of prominent Pd(2+) with a small quantity (18%) of reduced PdO (Pd(0)) in nanocrystalline PdO thin film. From the absorption spectroscopic measurement, the band gap energy of PdO was estimated to be 2 eV, which was very close to that obtained from specular reflectance measurements. Surface morphology studies of these films using atomic force microscopy and field-emission scanning electron microscopy indicated formation of nanoparticles of size 20-30 nm. These PdO film when employed as a chemiresistive sensor showed H2 sensitivity in the range of 30-4000 ppm at room temperature. In addition, PdO films showed photosensitivity with increase in current upon shining of visible light.

  11. Reduction of Sn-Bearing Iron Concentrate with Mixed H2/CO Gas for Preparation of Sn-Enriched Direct Reduced Iron

    Science.gov (United States)

    You, Zhixiong; Li, Guanghui; Wen, Peidan; Peng, Zhiwei; Zhang, Yuanbo; Jiang, Tao

    2017-06-01

    The development of manufacturing technology of Sn-bearing stainless steel inspires a novel concept for using Sn-bearing complex iron ore via reduction with mixed H2/CO gas to prepare Sn-enriched direct reduced iron (DRI). The thermodynamic analysis of the reduction process confirms the easy reduction of stannic oxide to metallic tin and the rigorous conditions for volatilizing SnO. Although the removal of tin is feasible by reduction of the pellet at 1223 K (950 °C) with mixed gas of 5 vol pct H2, 28.5 vol pct CO, and 66.5 vol pct CO2 (CO/(CO + CO2) = 30 pct), it is necessary that the pellet be further reduced for preparing DRI. In contrast, maintaining Sn in the metallic pellet is demonstrated to be a promising way to effectively use the ore. It is indicated that only 5.5 pct of Sn is volatilized when the pellet is reduced at 1223 K (950 °C) for 30 minutes with the mixed gas of 50 vol pct H2, 50 vol pct CO (CO/(CO + CO2) = 100 pct). A metallic pellet (Sn-bearing DRI) with Sn content of 0.293 pct, Fe metallization of 93.5 pct, and total iron content of 88.2 pct is prepared as a raw material for producing Sn-bearing stainless steel. The reduced tin in the Sn-bearing DRI either combines with metallic iron to form Sn-Fe alloy or it remains intact.

  12. Reduction of Sn-Bearing Iron Concentrate with Mixed H2/CO Gas for Preparation of Sn-Enriched Direct Reduced Iron

    Science.gov (United States)

    You, Zhixiong; Li, Guanghui; Wen, Peidan; Peng, Zhiwei; Zhang, Yuanbo; Jiang, Tao

    2017-02-01

    The development of manufacturing technology of Sn-bearing stainless steel inspires a novel concept for using Sn-bearing complex iron ore via reduction with mixed H2/CO gas to prepare Sn-enriched direct reduced iron (DRI). The thermodynamic analysis of the reduction process confirms the easy reduction of stannic oxide to metallic tin and the rigorous conditions for volatilizing SnO. Although the removal of tin is feasible by reduction of the pellet at 1223 K (950 °C) with mixed gas of 5 vol pct H2, 28.5 vol pct CO, and 66.5 vol pct CO2 (CO/(CO + CO2) = 30 pct), it is necessary that the pellet be further reduced for preparing DRI. In contrast, maintaining Sn in the metallic pellet is demonstrated to be a promising way to effectively use the ore. It is indicated that only 5.5 pct of Sn is volatilized when the pellet is reduced at 1223 K (950 °C) for 30 minutes with the mixed gas of 50 vol pct H2, 50 vol pct CO (CO/(CO + CO2) = 100 pct). A metallic pellet (Sn-bearing DRI) with Sn content of 0.293 pct, Fe metallization of 93.5 pct, and total iron content of 88.2 pct is prepared as a raw material for producing Sn-bearing stainless steel. The reduced tin in the Sn-bearing DRI either combines with metallic iron to form Sn-Fe alloy or it remains intact.

  13. Selective Plasmonic Gas Sensing: H2, NO2, and CO Spectral Discrimination by a Single Au-CeO2 Nanocomposite Film

    Energy Technology Data Exchange (ETDEWEB)

    Joy, N.; Nandasiri, Manjula I.; Rogers, Phillip H.; Jiang, Weilin; Varga, Tamas; Kuchibhatla, Satyanarayana V N T; Thevuthasan, Suntharampillai; Carpenter, Michael A.

    2012-06-05

    A Au-CeO2 nanocomposite film has been investigated as a potential sensing element for high-temperature plasmonic sensing of H2, CO, and NO2 in an oxygen containing environment. The CeO2 thin film was deposited by molecular beam epitaxy (MBE) and Au was implanted into the as-grown film at an elevated temperature followed by high temperature annealing to form well-defined Au nanoclusters. The Au-CeO2 nanocomposite film was characterized by x-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS). For the gas sensing experiments, separate exposures to varying concentrations of H2, CO, and NO2 were performed at a temperature of 500°C in oxygen backgrounds of 5.0, 10, and ~21% O2. Changes in the localized surface plasmon resonance (LSPR) absorption peak were monitored during gas exposures and are believed to be the result of oxidation-reduction processes that fill or create oxygen vacancies in the CeO2. This process affects the LSPR peak position either by charge exchange with the Au nanoparticles or by changes in the dielectric constant surrounding the particles. Multivariate analysis was used to gauge the inherent selectivity of the film between the separate analytes. From principal component analysis (PCA), unique and identifiable responses were seen for each of the analytes. Linear discriminant analysis (LDA) was also used and showed separation between analytes as well as trends in gas concentration. Results indicate that the Au-CeO2 thin film is selective to O2, H2, CO, and NO2 in separate exposures. Combined with the observed stability over long exposure periods, the Au-CeO2 film shows good potential as an optical sensing element for harsh environmental conditions.

  14. 高气速间歇式生物过滤去除高负荷H2S%A biofilter treating hydrogen sulfide with high load and gas velocity in intermittent mode

    Institute of Scientific and Technical Information of China (English)

    吴丹; 朱琳; 王俭; 刘强; 唐音; 桂居铎

    2013-01-01

    采用生物过滤法,以鸡粪堆肥和PE混合物为填料,在高气速条件下间歇式处理高负荷H2S废气.空床停留时间为20、15、10、6.7和5 s时,入口浓度3 000 mg/m3下的平均去除率分别为100%、100%、96.5%、89.2%和90.5%.高气速EBRT为5 s时,高入口负荷2 147 g/(m3·h)时的去除负荷为2023 g/(m3·h),去除率达94%.采用Michaelis-Ment-en模型进行生物降解宏观动力学研究,其中Ks为550 mg/m3,Vm为6.8 ×104 g/(m3·d).结果表明,在实验温度17~24℃,湿度30% ~ 50%下,生物过滤法间歇式处理高气速高负荷H2S的去除性能好.%Biological removal of hydrogen sulfide with high load and high gas velocity in intermittent mode in a biofilter, packed with the mixtures of chicken manure and polyethylene (PE) was investigated. With H2S inlet concentration of 3 000 mg/m3 and empty bed residence time (EBRT) of 20, 15, 10, 6. 7 and 5 s, the average removal efficiencies were 100% , 100% , 96. 5% , 89. 2% and 90. 5% , respectively. At the high gas velocity corresponding to EBRT of 5 s, the elimination capacity was 2 023 g/( m3 · h) with high inlet load of 2 147 g/(m · h) , and H2S removal efficiencies could reach 94% . The removal kinetics was researched based on the Michaelis-Menten model. Two kinetic parameters were Kt with a value of 550 mg/m3, and Vm with a value of 6. 8 ×104 g/(m · d). The results showed that a good performance of the biofilter is obtained with high load and gas velocity under conditions of temperature from 17 to 24℃ and the moisture content ranges from 30% to 50% .

  15. Simulation of the growth kinetics of boride layers formed on Fe during gas boriding in H2-BCl3 atmosphere

    Science.gov (United States)

    Kulka, M.; Makuch, N.; Pertek, A.; Małdziński, L.

    2013-03-01

    The modeling of the boriding kinetics is considered as a necessary tool to select the suitable process parameters for obtaining boride layer of an adequate thickness. Therefore, the simulation of the growth kinetics of boride layers has gained much attention for last years. The majority of the published works described the kinetics of the pack-boriding or paste-boriding. In this study, the model of growth kinetics of two-phase boride layer (FeB+Fe2B) on pure Fe was proposed for gas boriding. Displacements of the two interfaces (FeB/Fe2B and Fe2B/substrate) resulted from a difference of the arrival flux of interstitial boron atoms to one phase and the departure flux of the boron atoms from this phase to the second phase. The mass balance equations were formulated. The measurements of thickness of both zones (FeB and Fe2B), for different temperature of boriding, were used for calculations. Based on the experimental data, the parabolic growth constants AFeB and B versus the temperature of boriding were determined. The linear relationships were accepted. As a consequence, the activation energies (QFeB and Q) were calculated. The calculated values were comparable to other data derived from gas boriding. The presented model can predict the thicknesses of the FeB and Fe2B zones (XFeB and Y, respectively) formed on pure Fe during gas boriding. Additionally, the diffusion annealing after boriding was analyzed. This process was carried out in order to obtain a single-phase boride layer (Fe2B). The relationship between the reduction in FeB zone (dXFeB) and the growth in Fe2B phase (dY) was determined. The time tXFeB=0, needed for the total elimination of FeB phase in the boride layer was calculated and compared to the experimental data.

  16. Energy-filtered environmental transmission electron microscopy for the assessment of solid-gas reactions at elevated temperature: NiO/YSZ-H2 as a case study

    DEFF Research Database (Denmark)

    Jeangros, Q.; Hansen, Thomas Willum; Wagner, Jakob Birkedal

    2016-01-01

    A novel approach, which is based on the analysis of sequences of images recorded using energy-filtered transmission electron microscopy and can be used to assess the reaction of a solid with a gas at elevated temperature, is illustrated for the reduction of a NiO/ceramic solid oxide fuel cell anode...... in 1.3mbar of H2. Three-window elemental maps and jump-ratio images of the O K edge and total inelastic mean free path images are recorded as a function of temperature and used to provide local and quantitative information about the reaction kinetics and the volume changes that result from the reaction...

  17. Morphology, luminescence, and electrical resistance response to H 2 and CO gas exposure of porous InP membranes prepared by electrochemistry in a neutral electrolyte

    Science.gov (United States)

    Volciuc, O.; Monaico, E.; Enachi, M.; Ursaki, V. V.; Pavlidis, D.; Popa, V.; Tiginyanu, I. M.

    2010-11-01

    Porous InP membranes have been prepared by anodization of InP wafers with electron concentration of 1 × 10 17 cm -3 and 1 × 10 18 cm -3 in a neutral NaCl electrolyte. The internal surfaces of pores in some membranes were modified by electrochemical deposition of gold in a pulsed voltage regime. Photoluminescence and photosensitivity measurements indicate efficient light trapping and porous surface passivation. The photoluminescence and electrical resistivity of the membranes are sensitive to the adsorption of H 2 and CO gas molecules. These properties are also influenced by the deposition of Au nanoparticles inside the pores.

  18. A classification and ranking system on the H2 gas sensing capabilities of nanomaterials based on proposed coefficients of sensor performance and sensor efficiency equations

    CSIR Research Space (South Africa)

    Mwakikunga, BW

    2013-07-01

    Full Text Available Sensors and Actuators B 184 (2013) 170– 178 A classification and ranking system on the H2 gas sensing capabilities of nanomaterials based on proposed coefficients of sensor performance and sensor efficiency equations Bonex W. Mwakikungaa,b,∗, Sarah... Motshekgaa, Lucky Sikhwivhilua,c, Mathew Moodleya, Manfred Scribaa, Gerald Malgasa, A. Simod, B. Soned, M. Maazad,e, Suprakas Sinha Raya,f,∗ a DST/CSIR National Centre for Nano-Structured Materials, Pretoria 0001, South Africa b Department of Physics...

  19. Thermodynamic characterization of gas mixtures to introduce alternative gas fuels in the natural gas grids

    OpenAIRE

    Hernández Gómez, Roberto

    2016-01-01

    La investigación desarrollada en este trabajo de tesis doctoral pretende contribuir al desarrollo e introducción de nuevos combustibles gaseosos de origen renovable en el mix energético europeo a través de la caracterización termodinámica de mezclas de los componentes principales de estos combustibles alternativos. La tesis aporta datos (p, ρ, T) experimentales de alta precisión de tres mezclas binarias de (CH4 + He) con (5, 10 y 50 mol-% He), una mezcla sintética de un gas no-convencional...

  20. Candidate eco-friendly gas mixtures for MPGDs

    CERN Document Server

    AUTHOR|(CDS)2071648; Saviano, G.; Muhammad, S.; Piccolo, D.; Primavera, F.; Ferrini, M.; Parvis, M.; Grassing, S.; Colafranceschi, S.; Kjøbro, J.; Sharma, A.; Yang, D.; Chen, G.; Ban, Y.; Li, Q.

    2015-01-01

    Modern gas detectors for detection of particles require F-based gases for optimal performance. Recent regulations demand the use of environmentally unfriendly F-based gases to be limited or banned. This review studies properties of potential eco-friendly gas candidate replacements.

  1. Affects of Mechanical Milling and Metal Oxide Additives on Sorption Kinetics of 1:1 LiNH2/MgH2 Mixture

    Directory of Open Access Journals (Sweden)

    Donald L. Anton

    2011-05-01

    Full Text Available The destabilized complex hydride system composed of LiNH2:MgH2 (1:1 molar ratio is one of the leading candidates of hydrogen storage with a reversible hydrogen storage capacity of 8.1 wt%. A low sorption enthalpy of ~32 kJ/mole H2 was first predicted by Alapati et al. utilizing first principle density function theory (DFT calculations and has been subsequently confirmed empirically by Lu et al. through differential thermal analysis (DTA. This enthalpy suggests that favorable sorption kinetics should be obtainable at temperatures in the range of 160 °C to 200 °C. Preliminary experiments reported in the literature indicate that sorption kinetics are substantially lower than expected in this temperature range despite favorable thermodynamics. Systematic isothermal and isobaric sorption experiments were performed using a Sievert’s apparatus to form a baseline data set by which to compare kinetic results over the pressure and temperature range anticipated for use of this material as a hydrogen storage media. Various material preparation methods and compositional modifications were performed in attempts to increase the kinetics while lowering the sorption temperatures. This paper outlines the results of these systematic tests and describes a number of beneficial additions which influence kinetics as well as NH3 formation.

  2. Sulfur-doped graphene via thermal exfoliation of graphite oxide in H2S, SO2, or CS2 gas.

    Science.gov (United States)

    Poh, Hwee Ling; Šimek, Petr; Sofer, Zdeněk; Pumera, Martin

    2013-06-25

    Doping of graphene with heteroatoms is an effective way to tailor its properties. Here we describe a simple and scalable method of doping graphene lattice with sulfur atoms during the thermal exfoliation process of graphite oxides. The graphite oxides were first prepared by Staudenmaier, Hofmann, and Hummers methods followed by treatments in hydrogen sulfide, sulfur dioxide, or carbon disulfide. The doped materials were characterized by scanning electron microscopy, high-resolution X-ray photoelectron spectroscopy, combustible elemental analysis, and Raman spectroscopy. The ζ-potential and conductivity of sulfur-doped graphenes were also investigated in this paper. It was found that the level of doping is more dramatically influenced by the type of graphite oxide used rather than the type of sulfur-containing gas used during exfoliation. Resulting sulfur-doped graphenes act as metal-free electrocatalysts for an oxygen reduction reaction.

  3. Irreversible Processes in a Universe modelled as a mixture of a Chaplygin gas and radiation

    CERN Document Server

    Kremer, G M

    2003-01-01

    The evolution of a Universe modelled as a mixture of a Chaplygin gas and radiation is determined by taking into account irreversible processes. This mixture could interpolate periods of a radiation dominated, a matter dominated and a cosmological constant dominated Universe. The results of a Universe modelled by this mixture are compared with the results of a mixture whose constituents are radiation and quintessence. Among other results it is shown that: (a) for both models there exists a period of a past deceleration with a present acceleration; (b) the slope of the acceleration of the Universe modelled as a mixture of a Chaplygin gas with radiation is more pronounced than that modelled as a mixture of quintessence and radiation; (c) the energy density of the Chaplygin gas tends to a constant value at earlier times than the energy density of quintessence does; (d) the energy density of radiation for both mixtures coincide and decay more rapidly than the energy densities of the Chaplygin gas and of quintessen...

  4. Study On H_2S/CO_2 Corrosion Behavior of Pipeline Steel in Wet Gas%管线钢在湿气介质中的H_2S/CO_2腐蚀行为研究

    Institute of Scientific and Technical Information of China (English)

    杨建炜; 张雷; 丁睿明; 路民旭

    2008-01-01

    利用高温高压反应釜模拟高含硫气田H_2S/CO_2共存环境,在流动湿H_2S/CO_2介质中进行腐蚀实验,辅以SEM,EDS和XRD,探讨了湿气介质中高H_2S分压对API-X52和API-X60管线钢H_2S/CO_2腐蚀行为的影响.两种钢在湿气介质中的腐蚀速率均随H_2S分压的升高而增加,X60腐蚀速率略高于X52,随着H_2S分压由0.15MPa增至2.0MPa,腐蚀形态由全面腐蚀趋向局部腐蚀,腐蚀过程由H_2S控制,腐蚀产物以四方晶系的FeS_(1-x)(Mackinawite)为主.X60钢表面出现氢鼓泡,内部发生氢致开裂.

  5. Consideration of the H2S Effect on Safety Production in Natural Gas Purification Plant%对天然气净化厂H2S安全防护问题的思考

    Institute of Scientific and Technical Information of China (English)

    姜云

    2005-01-01

    在天然气净化厂生产中,必须重视H2S的安全防护问题.作者从净化厂原料气、酸气、富液、酸水、酸性废渣及设备腐蚀等方面,分析了存在H2S中毒的危险因素,提出了防止H2S中毒事故,保证安全生产的措施.

  6. A Study on the Effects of Carrier Gases on the Structure and Morphology of Carbon Nanotubes Prepared by Pyrolysis of Ferrocene and C2H2 Mixture

    Institute of Scientific and Technical Information of China (English)

    Wanliang Mi; Jerry Yuesheng Lin; Qian Mao; Yongdan Li; Baoquan Zhang

    2005-01-01

    Carbon nanotubes (CNTs) were prepared using different carrier gases,with ferrocene as the catalyst precusor and acetylene as the carbon source. The effects of ammonia and nitrogen as carrier gases on the structure and morphology of CNTs were investigated. Transmission electron microscope (TEM),high-resolution electron microscope (HRTEM),scanning electron microscope (SEM) and X-ray diffraction (XRD) were employed to characterize the products and the catalyst. Experiment results show that the CNTs grown in N2 gas exhibited cylindrical and tubular structure,while a bamboo-like structure was observed for the CNTs grown in NH3 gas. Moreover,vertically aligned CNTs were obtained on an Al2O3 disk when NH3 was used as the carrier gas. The carrier gas also exerted influence on the shape of the catalyst. Based on the theory of active centers of catalysis and combined with the particle shape of the catalyst,a growth model for the vertically aligned CNTs on the substrate is given.

  7. Study of low-defect and strain-relaxed GeSn growth via reduced pressure CVD in H2 and N2 carrier gas

    Science.gov (United States)

    Margetis, J.; Mosleh, A.; Al-Kabi, S.; Ghetmiri, S. A.; Du, W.; Dou, W.; Benamara, M.; Li, B.; Mortazavi, M.; Naseem, H. A.; Yu, S.-Q.; Tolle, J.

    2017-04-01

    High quality, thick (up to 1.1 μm), strain relaxed GeSn alloys were grown on Ge-buffered Si (1 0 0) in an ASM Epsilon® chemical vapor deposition system using SnCl4 and low-cost commercial GeH4 precursors. The significance of surface chemistry in regards to growth rate and Sn-incorporation is discussed by comparing growth kinetics data in H2 and N2 carrier gas. The role of carrier gas is also explored in the suppression of Sn surface segregation and evolution of layer composition and strain profiles via secondary ion mass spectrometry and X-ray diffraction. Transmission electron microscopy revealed the spontaneous compositional splitting and formation of a thin intermediate layer in which dislocations are pinned. This intermediate layer enables the growth of a thick, strain relaxed, and defect-free epitaxial layer on its top. Last, we present photoluminescence results which indicate that both N2 and H2 growth methods produce optoelectronic device quality material.

  8. Utilization of CO2 and biomass char derived from pyrolysis of Dunaliella salina: the effects of steam and catalyst on CO and H2 gas production.

    Science.gov (United States)

    Yang, Chao; Jia, Lishan; Su, Shuai; Tian, Zhongbiao; Song, Qianqian; Fang, Weiping; Chen, Changping; Liu, Guangfa

    2012-04-01

    Biomass char, by-product of Dunaliella salina pyrolysis at a final pyrolysis temperature of 500°C, was used as feedstock material in this study. The reactions of biomass char with CO(2) were performed in a fixed-bed reactor to evaluate the effect of temperature and steam on the CO(2) conversion, CO yield and gas composition. The CO(2) conversion and CO yield without steam and catalyst reached about 61.84% and 0.99mol/(mol CO(2)) at 800°C, respectively. Steam and high temperature led to high CO(2) conversion. A new approach for improving H(2) was carried out by using biomass char and Au/Al(2)O(3) catalyst, which combined steam gasification of biomass char and water gas shift reaction, and the H(2) concentration was 1.8 times higher than without catalyst. The process not only mitigated CO(2) emission and made use of residual biomass char, but also created renewable source.

  9. Mixture

    Directory of Open Access Journals (Sweden)

    Silva-Aguilar Martín

    2011-01-01

    Full Text Available Metals are ubiquitous pollutants present as mixtures. In particular, mixture of arsenic-cadmium-lead is among the leading toxic agents detected in the environment. These metals have carcinogenic and cell-transforming potential. In this study, we used a two step cell transformation model, to determine the role of oxidative stress in transformation induced by a mixture of arsenic-cadmium-lead. Oxidative damage and antioxidant response were determined. Metal mixture treatment induces the increase of damage markers and the antioxidant response. Loss of cell viability and increased transforming potential were observed during the promotion phase. This finding correlated significantly with generation of reactive oxygen species. Cotreatment with N-acetyl-cysteine induces effect on the transforming capacity; while a diminution was found in initiation, in promotion phase a total block of the transforming capacity was observed. Our results suggest that oxidative stress generated by metal mixture plays an important role only in promotion phase promoting transforming capacity.

  10. Numerical simulation of the passive gas mixture flow

    Directory of Open Access Journals (Sweden)

    Kyncl Martin

    2015-01-01

    Full Text Available We work with the system of equations describing non-stationary compressible turbulent multicomponent flow in the gravitational field, and we focus on the numerical solution of these equations. In these computations we assume the mixture of perfect inert gases. The thermodynamic constants are functions in time and space. The finite volume method is used. In order to solve the local boundary problem at each mesh face, we use the original analysis of the exact solution of the Riemann problem. The roughness of the surface is simulated via the specific dissipation at the wall. We show the computational results obtained with the own-developed code (C,FORTRAN for the solution of the 3D compressible turbulent mixture flow. The originality of this work lies with the special handling of the boundary conditions, which shows superior behavior, and own computational code.

  11. Isotope fractionation in aqua-gas systems: Cl(2)-HCl-Cl(-), Br(2)-HBr-Br(-) and H(2)S-S(2-).

    Science.gov (United States)

    Czarnacki, Maciej; Hałas, Stanisław

    2012-01-01

    We report calculated values of isotope fractionation factors between chlorine, bromine and sulphide hydrated anions and respective gaseous compounds: hydrogen chloride, hydrogen bromide, molecular chlorine and bromine and hydrogen sulphide. For the calculation of the reduced partition function ratios (β-factors) of hydrated Cl(-), Br(-) and S(2-) anions, we used a model of a cluster composed of the considered ion surrounded by two shells of H(2)O molecules. Only the electrostatic interaction between ion and water molecules treated as electric dipoles was taken into account. The β-factors for the gaseous compounds (HCl, Cl(2), HBr, Br(2) and H(2)S) were calculated from vibrational frequencies reported by Urey and Greiff [Isotopic Exchange Equilibria, J. Am. Chem. Soc. 57, 321 (1935)] and Schauble et al. [Theoretical Estimates Equilibrium Chlorine-Isotope Fractionation, Geochim. Cosmochim. Acta 67, 3267 (2003)]. Low-temperature isotope fractionation between chlorine-hydrated anion and hydrogen chloride attains 1.55-1.68‰ (this work), which is in good agreement with experimental data (1.4-1.8‰) [Z.D. Sharp, J.D. Barnes, T.P. Fischer and M. Halick, An Experimental Determination of Chlorine Isotope Fractionation in Acid Systems and Applications to Volcanic Fumaroles, Geochim. Cosmochim. Acta 74, 264 (2010)]. The predicted isotope fractionations for hydrated bromine and HBr, Br(2) gases are very small, 1000 ln α, do not exceed 0.8‰; thus, the expected variations of bromine isotope composition in aqua-gas systems will require enhanced precision for their detection. In contrast, the sulphur isotope fractionation between H(2)S( gas ) and S(2-) attains 6.0‰ at room temperature and drops nearly linearly to 3.1‰ at 350°C.

  12. Methanol synthesis on potassium modified Cu(100) from CO + H2 and CO + CO2 +H2

    DEFF Research Database (Denmark)

    Maack, M.; Friis-Jensen, Henriette; Sckerl, Susanne Quist;

    2003-01-01

    Methanol cannot be produced from CO + H-2 on a clean copper surface, but a promotional effect of potassium on methanol synthesis from mixtures of CO + H-2 and CO = CO2 + H-2 at a total pressure of 1.5 bar on a Cu(100) surface is shown in this work. The experiments are performed in a UHV chamber...... connected with a high-pressure cell (HPC). The methanol produced is measured with a gas chromatograph and the surface is characterized with surface science techniques. The results show that potassium is a promoter for the methanol synthesis from CO + H-2, and that the influence of CO2 is negligible....... Investigation of the post-reaction surface with TPD indicates that potassium carbonate is present and plays an important role. The activation energy is determined as 42 +/- 3 kJ/mol for methanol synthesis on K/Cu(100) from CO + H-2....

  13. More environment-friendly and safer working gas mixtures for Bakelite RPCs operated in streamer mode

    Science.gov (United States)

    Zhang, Qingmin; Lv, Zhipeng; Lv, Jinge; Zhang, Jiawen; Xu, Jilei; Ning, Zhe

    2017-08-01

    This paper presents experimental results of RPCs performances with different working gas mixtures. Owing to Freon's high global warming potential, its threat to RPCs aging and its large consumption in large particle physics experiments, studies to minimize the concentration of HFC-134A, and even its complete replacement, have been undertaken. In addition, the reduction of iso-butane is also a favorable strategy, due to the flammability level of the gas mixture. Freon-less working gas mixture of Ar/HFC-134A/i-C4H10/CO2=20/0/8/72 was chosen with plateau efficiency of 86.3% and noise rate of 0.61 Hz/cm2. For working gas with lower ratio of Freon, Ar/HFC-134A/i-C4H10/CO2=20/20/8/52 was suggested with plateau efficiency of 91.0% and noise rate of 0.19 Hz/cm2, in which Freon was decreased by 22% compared to the BESIII RPC gas mixture. Furthermore, iso-butane was decreased to 6% with RPC's efficiency of 90% and noise rate of 0.20 Hz/cm2 achieved. Finally, the explanation of RPC's different performances at various working gas mixtures has been validated by the investigation of secondary streamers. This study will be helpful for RPC's application in future large particle physics experiments, in which RPCs can run in streamer mode.

  14. 中空纤维膜吸收法脱除H2S的实验研究%Experimental Study on Membrane Gas Absorption for H2S Removal Using Hollow Fiber Membrane

    Institute of Scientific and Technical Information of China (English)

    邢宪锋; 赵会军; 王树立

    2008-01-01

    研究了用中空纤维膜组件脱除天然气中的H2S的吸收过程.采用疏水性聚丙烯中空纤维膜(HFPPM)制成膜组件,以甲基二乙醇胺(MDEA)水溶液作为吸收剂,考察了吸收液浓度、吸收液流速、气相流速等因素对H2S膜吸收过程的影响.实验结果表明,质量分数为30%的MDEA吸收液在流速为78.1 ml/s,气速为0.064 m/s时,H2S的脱除率为95.8%,H2S的总传质系数为4.8×10-8mol·(m2·s·Pa)-1;质量分数为35%的MDEA在同样的条件下H2S脱除率达98.1%.而且在实验的较宽天然气H2S浓度范围内,MDEA吸收剂H2S脱除率保持在90%以上.实验证明膜吸收法也许是有良好发展前景脱除H2S的方法.

  15. DISCRETE PARTICLE SIMULATION OF SIZE SEGREGATION OF PARTICLE MIXTURES IN A GAS FLUIDIZED BED

    Institute of Scientific and Technical Information of China (English)

    Y. Q. Feng; A. B. Yu

    2006-01-01

    This paper presents a study of the mixing/segregation behaviour of particle mixtures in a gas fluidized bed by use of the discrete particle simulation. Spherical particles with diameters 2 mm (jetsam) and 1 mm (flotsam) and density 2 500 kg·m-3 are used as solid mixtures with different volume fractions. The particles are initially packed uniformly in a rectangular bed and then fluidized by gas uniformly injected at the bottom of the bed. The gas injection velocities vary to cover fixed, partially and fully fluidized bed conditions. Segregation/mixing behaviour is discussed in terms of flow patterns, solid concentration profile and mixing kinetics. The results show that segregation, as a transient fluidization process, is strongly affected by gas injection velocities for a given particle mixture. With the increase of the volume fraction of flotsam, size segregation appears at lower velocities.

  16. 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

  17. Gravimetric dilution of calibration gas mixtures (CO2, CO, and CH4 in He balance): Toward their uncertainty estimation

    Science.gov (United States)

    Budiman, Harry; Mulyana, Muhammad Rizky; Zuas, Oman

    2017-01-01

    Uncertainty estimation for the gravimetric dilution of four calibration gas mixtures [carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4) in helium (He) Balance] have been carried out according to the International Organization for Standardization (ISO) of "Guide to the Expression of Uncertainty in Measurement". The uncertainty of the composition of gas mixtures was evaluated to measure the quality, reliability, and comparability of the prepared calibration gas mixtures. The analytical process for the uncertainty estimation is comprised of four main stages such as specification of measurand, identification, quantification of the relevant uncertainty sources, and combination of the individual uncertainty sources. In this study, important uncertainty sources including weighing, gas cylinder, component gas, certified calibration gas mixture (CCGM) added, and purity of the He balance were examined to estimate the final uncertainty of composition of diluted calibration gas mixtures. The results shows that the uncertainties of gravimetric dilution of the four calibration gas mixtures (CO2, CO, and CH4 in He Balance) were found in the range of 5.974% - 7.256% that were expressed as %relative of expanded uncertainty at 95% of confidence level (k=2). The major contribution of sources uncertainty to the final uncertainty arose from the uncertainty related to the certified calibration gas mixture (CCGM) which was the uncertainty value stated in the CCGM certificate. The verification of calibration gas mixtures composition shows that the gravimetric values of calibration gas mixtures were consistent with the results of measurement using gas chromatography flame ionization detector equipped by methanizer.

  18. Cleavage of catalytic ally grown carbon nanofibers into hydrophilic segments by oxidation in a mixture of concentrated HNO3-H2SO4 in an autoclave

    Institute of Scientific and Technical Information of China (English)

    TENG Li-hua; WANG Zhi-jiang; TANG Tian-di

    2012-01-01

    The catalytically grown carbon nanofibers were treated by a mixture of concentrated nitric aid and sulfuric aid in an autoclave at temperature 333,363 and 423 K.It was found that the samples treated at 363 K and 423 K were still well dispersed in water 15 hours later,indicating that carbon nanofibers can be made hydrophilicy.It was also found that the dispersion was destroyed when the pH value was lowered by adding acid.The results are significant when the carbon nanofibers are used as enhancing component in polymer composite material because several hundreds of nm are perfect size and the hydrophilicity controls the dispersion of CNFs in the polymer media.It is concluded that the amount of the oxygen-containing groups on the surface and the hydrophilicity of the carbon nanofibers can be controlled by the treatment temperature,and that the carbon nanofibers can be cleaved into uniform segments.

  19. Development of Innovating Materials for Distributing Mixtures of Hydrogen and Natural Gas. Study of the Barrier Properties and Durability of Polymer Pipes

    Directory of Open Access Journals (Sweden)

    Klopffer Marie-Hélène

    2015-02-01

    Full Text Available With the growing place taken by hydrogen, a question still remains about its delivery and transport from the production site to the end user by employing the existing extensive natural gas pipelines. Indeed, the key challenge is the significant H2 permeation through polymer infrastructures (PolyEthylene (PE pipes, components such as connecting parts. This high flow rate of H2 through PE has to be taken into account for safety and economic requirements. A 3-year project was launched, the aim of which was to develop and assess material solutions to cope with present problems for hydrogen gas distribution and to sustain higher pressure compared to classical high density polyethylene pipe. This project investigated pure hydrogen gas and mixtures with natural gas (20% of CH4 and 80% of H2 in pipelines with the aim to select engineering polymers which are more innovative than polyethylene and show outstanding properties, in terms of permeation, basic mechanical tests but also more specific characterizations such as long term ageing and behaviour. The adequate benches, equipments and scientific approach for materials testing had been developed and validated. In this context, the paper will focus on the evaluation of the barrier properties of 3 polymers (PE, PA11 and PAHM. Experiments were performed for pure H2 and CH4 and also in the presence of mixtures of hydrogen and natural gas in order to study the possible mixing effects of gases. It will report some round-robin tests that have been carried out. Secondly, by comparing data obtained on film, polymer membrane and on pipe section, the influence of the polymer processing will be studied. Innovative multilayers systems will be proposed and compared on the basis of the results obtained on monolayer systems. Finally, the evolution of the transport properties of the studied polymers with an ageing under representative service conditions will be discussed.

  20. First detection of gas-phase ammonia in a planet-forming disk. NH3, N2H+, and H2O in the disk around TW Hydrae

    Science.gov (United States)

    Salinas, Vachail N.; Hogerheijde, Michiel R.; Bergin, Edwin A.; Cleeves, L. Ilsedore; Brinch, Christian; Blake, Geoffrey A.; Lis, Dariusz C.; Melnick, Gary J.; Panić, Olja; Pearson, John C.; Kristensen, Lars; Yıldız, Umut A.; van Dishoeck, Ewine F.

    2016-06-01

    Context. Nitrogen chemistry in protoplanetary disks and the freeze-out on dust particles is key for understanding the formation of nitrogen-bearing species in early solar system analogs. In dense cores, 10% to 20% of the nitrogen reservoir is locked up in ices such as NH3, NH4+ and OCN-. So far, ammonia has not been detected beyond the snowline in protoplanetary disks. Aims: We aim to find gas-phase ammonia in a protoplanetary disk and characterize its abundance with respect to water vapor. Methods: Using HIFI on the Herschel Space Observatory, we detected for the first time the ground-state rotational emission of ortho-NH3 in a protoplanetary disk around TW Hya. We used detailed models of the disk's physical structure and the chemistry of ammonia and water to infer the amounts of gas-phase molecules of these species. We explored two radial distributions (extended across the disk and confined to distributions (near the midplane and at intermediate heights above the midplane, where water is expected to photodesorb off icy grains) to describe the (unknown) location of the molecules. These distributions capture the effects of radial drift and vertical settling of ice-covered grains. Results: The NH310-00 line is detected simultaneously with H2O 110-101 at an antenna temperature of 15.3 mK in the Herschel beam; the same spectrum also contains the N2H+ 6-5 line with a strength of 18.1 mK. We use physical-chemical models to reproduce the fluxes and assume that water and ammonia are cospatial. We infer ammonia gas-phase masses of 0.7-11.0 × 1021 g, depending on the adopted spatial distribution, in line with previous literature estimates. For water, we infer gas-phase masses of 0.2-16.0 × 1022 g, improving upon earlier literature estimates This corresponds to NH3/H2O abundance ratios of 7%-84%, assuming that water and ammonia are co-located. The inferred N2H+ gas mass of 4.9 × 1021 g agrees well with earlier literature estimates that were based on lower excitation

  1. Laser flash-photolysis and gas discharge in N2O-containing mixture: kinetic mechanism

    Science.gov (United States)

    Kosarev, Ilya; Popov, Nikolay; Starikovskaia, Svetlana; Starikovskiy, Andrey; mipt Team

    2011-10-01

    The paper is devoted to further experimental and theoretical analysis of ignition by ArF laser flash-photolysis and nanosecond discharge in N2O-containing mixture has been done. Additional experiments have been made to assure that laser emission is distributed uniformly throughout the cross-section. The series of experiments was proposed and carried out to check validity of O(1D) determination in experiments on plasma assisted ignition initiated by flash-photolysis. In these experiments, ozone density in the given mixture (mixture composition and kinetics has been preliminary analyzed) was measured using UV light absorption in Hartley band. Good coincidence between experimental data and results of calculations have been obtained Temporal behavior of energy input, electric field and electric current has been measured and analyzed. These data are considered as initial conditions for numerical modeling of the discharge in O2:N2O:H2:Ar = 0.3:1:3:5 mixture. Ion-molecular reactions and reactions of active species production in Ar:H2:O2:N2O mixture were analyzed. The set of reactions to describe chemical transformation in the system due to the discharge action has been selected.

  2. Proton irradiation of simple gas mixtures: Influence of irradiation parameters

    Science.gov (United States)

    Sack, Norbert J.; Schuster, R.; Hofmann, A.

    1990-01-01

    In order to get information about the influence of irradiation parameters on radiolysis processes of astrophysical interest, methane gas targets were irradiated with 6.5 MeV protons at a pressure of 1 bar and room temperature. Yields of higher hydrocarbons like ethane or propane were found by analysis of irradiated gas samples using gas chromatography. The handling of the proton beam was of great experimental importance for determining the irradiation parameters. In a series of experiments current density of the proton beam and total absorbed energy were shown to have a large influence on the yields of produced hydrocarbons. Mechanistic interpretations of the results are given and conclusions are drawn with regard to the chemistry and the simulation of various astrophysical systems.

  3. Candidate eco-friendly gas mixtures for MPGDs

    CERN Document Server

    Saviano, Giovanna

    2015-01-01

    Modern gas detectors for the detection of elementary particles, and MPGDs in particular, require F-based gases for optimal performance. Recent regulations demand the use of environmentally unfriendly F-based gases to be limited or banned. This work investigates the properties of potential eco-friendly gas candidate replacements. The aim is to discuss some of the important properties of gases for MPGDs, to list and summarize basic properties of eco-friendly refrigerants from the literature available, to discuss their properties for materials compatibility and safe use, and to make a prediction on selected parameters (i.e., ionization potentials, ionization pairs, etc) crucial for the performance of gas detectors considered by making use of both known parametrizations and quantum chemistry simulation codes.

  4. Rayleigh-Brillouin Scattering in Binary Gas Mixtures

    CERN Document Server

    Gu, Ziyu; van de Water, Willem; Marques, Wilson

    2015-01-01

    Precise measurements are performed on spectral lineshapes of spontaneous Rayleigh-Brillouin scattering in mixtures of the noble gases Ar and Kr, with He. Admixture of a light He atomic fraction results in marked changes of the spectra, although in all experiments He is merely a spectator atom: it affects the relaxation of density fluctuations of the heavy constituent, but its contribution to the scattered light intensity is negligibly small. The results are compared to a theory for the spectral lineshape without adjustable parameters, yielding excellent agreement for the case of binary mono-atomic gases, signifying a step towards modeling and understanding of light scattering in more complex molecular media.

  5. 固-气反应球磨制备纳米晶MgH2的研究%Preparation of Nanocrystalline MgH2 by Solid-Gas Reaction Milling in Hydrogen

    Institute of Scientific and Technical Information of China (English)

    王珩; 王辛; 胡连喜

    2009-01-01

    采用固.气反应球磨制备纳米晶MgH2粉末,测定纯镁粉在球磨过程中的吸氢动力学曲线.借助X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)等分析手段,研究Mg-H2反应球磨过程中的相结构与粉末形貌演变规律.结果表明,在机械球磨驱动作用下,Mg的吸氢过程可分为"缓慢-快速-饱和"3个阶段,其相组成分别对应"Mg(H)-Mg(H)+MgH2-MgH2".在0.5 MPa氢气压条件下,球磨21 h可使Mg完全氢化,获得粉末粒度1~3μm、晶粒尺寸10 nm左右的纳米晶MgH2粉末,其实际氢含量高达7.03%(质量分数,下同).

  6. Symmetry energy in the liquid-gas mixture

    Science.gov (United States)

    López, J. A.; Terrazas Porras, S.

    2017-01-01

    Results from classical molecular dynamics simulations of infinite nuclear systems with varying density, temperature and isospin content are used to calculate the symmetry energy at low densities. The results show an excellent agreement with the experimental data and corroborate the claim that the formation of clusters has a strong influence on the symmetry energy in the liquid-gas coexistence region.

  7. Symmetry energy in the liquid–gas mixture

    Energy Technology Data Exchange (ETDEWEB)

    López, J.A., E-mail: jorgelopez@utep.edu [University of Texas at El Paso, El Paso, TX 79968 (United States); Terrazas Porras, S. [Universidad Autónoma de Ciudad Juárez, Ciudad Juárez, Chihuahua (Mexico)

    2017-01-15

    Results from classical molecular dynamics simulations of infinite nuclear systems with varying density, temperature and isospin content are used to calculate the symmetry energy at low densities. The results show an excellent agreement with the experimental data and corroborate the claim that the formation of clusters has a strong influence on the symmetry energy in the liquid–gas coexistence region.

  8. HD/H2 as a Probe of the Roles of Gas, Dust, Light, Metallicity, and Cosmic Rays in Promoting the Growth of Molecular Hydrogen in the Diffuse Interstellar Medium

    Science.gov (United States)

    Liszt, H. S.

    2015-01-01

    We modeled recent observations of UV absorption of HD and {H_2} in the Milky Way and toward damped/subdamped Lyα systems at z = 0.18 and z >1.7. N(HD)/N({H_2}) ratios reflect the separate self-shieldings of HD and {H_2} and the coupling introduced by deuteration chemistry. Locally, observations are explained by diffuse molecular gas with 16 cm-3 1.7, N(HD) is comparable to the Galaxy but with 10 times smaller N({H_2}) and somewhat smaller N({H_2})/N(H I). Comparison of our Galaxy with the Magellanic Clouds shows that smaller {H_2}/H is expected at subsolar metallicity, and we show by modeling that HD/{H_2} increases with density at low metallicity, opposite to the Milky Way. Observations of HD would be explained with higher n(H) at low metallicity, but high-z systems have high HD/{H_2} at metallicity 0.04 shielding effects. The abrupt {H_2} transition to {H_2}/H ≈ 1%-10% occurs mostly from self-shielding, although it is assisted by extinction for n(H) <~ 16 cm-3. Interior {H_2} fractions are substantially increased by dust extinction below <~ 32 cm-3. At smaller n(H), ζ H , small increases in {H_2} triggered by dust extinction can trigger abrupt increases in N(HD).

  9. Measurement of nitrogen content in a gas mixture by transforming the nitrogen into a substance detectable with nondispersive infrared detection

    Science.gov (United States)

    Owen, Thomas E.; Miller, Michael A.

    2007-03-13

    A method of determining the amount of nitrogen in a gas mixture. The constituent gases of the mixture are dissociated and transformed to create a substance that may measured using nondispersive infrared adsorption techniques.

  10. Determination Of Gas Mixture Components Using Fluctuation Enhanced Sensing And The LS-SVM Regression Algorithm

    Directory of Open Access Journals (Sweden)

    Lentka Łukasz

    2015-09-01

    Full Text Available This paper analyses the effectiveness of determining gas concentrations by using a prototype WO3 resistive gas sensor together with fluctuation enhanced sensing. We have earlier demonstrated that this method can determine the composition of a gas mixture by using only a single sensor. In the present study, we apply Least-Squares Support-Vector-Machine-based (LS-SVM-based nonlinear regression to determine the gas concentration of each constituent in a mixture. We confirmed that the accuracy of the estimated gas concentration could be significantly improved by applying temperature change and ultraviolet irradiation of the WO3 layer. Fluctuation-enhanced sensing allowed us to predict the concentration of both component gases.

  11. Inflammable Gas Mixture Detection with a Single Catalytic Sensor Based on the Electric Field Effect

    Science.gov (United States)

    Tong, Ziyuan; Tong, Min-Ming; Meng, Wen; Li, Meng

    2014-01-01

    This paper introduces a new way to analyze mixtures of inflammable gases with a single catalytic sensor. The analysis technology was based on a new finding that an electric field on the catalytic sensor can change the output sensitivity of the sensor. The analysis of mixed inflammable gases results from processing the output signals obtained by adjusting the electric field parameter of the catalytic sensor. For the signal process, we designed a group of equations based on the heat balance of catalytic sensor expressing the relationship between the output signals and the concentration of gases. With these equations and the outputs of different electric fields, the gas concentration in a mixture could be calculated. In experiments, a mixture of methane, butane and ethane was analyzed by this new method, and the results showed that the concentration of each gas in the mixture could be detected with a single catalytic sensor, and the maximum relative error was less than 5%. PMID:24717635

  12. Performance Analysis of Joule-Thomson Cooler Supplied with Gas Mixtures

    Science.gov (United States)

    Piotrowska, A.; Chorowski, M.; Dorosz, P.

    2017-02-01

    Joule-Thomson (J-T) cryo-coolers working in closed cycles and supplied with gas mixtures are the subject of intensive research in different laboratories. The replacement of pure nitrogen by nitrogen-hydrocarbon mixtures allows to improve both thermodynamic parameters and economy of the refrigerators. It is possible to avoid high pressures in the heat exchanger and to use standard refrigeration compressor instead of gas bottles or high-pressure oil free compressor. Closed cycle and mixture filled Joule-Thomson cryogenic refrigerator providing 10-20 W of cooling power at temperature range 90-100 K has been designed and manufactured. Thermodynamic analysis including the optimization of the cryo-cooler mixture has been performed with ASPEN HYSYS software. The paper describes the design of the cryo-cooler and provides thermodynamic analysis of the system. The test results are presented and discussed.

  13. The axial symmetric vibrations of cylindrical shell, filled by the flowing Gas-Liquid mixture

    Directory of Open Access Journals (Sweden)

    Grigoryan Sh.H.

    2011-09-01

    Full Text Available The problem of axial symmetric self–vibrations of the infinite long shell, filled by flowing gas bubbles of large and small sizes in fluid mixture is considered. The subsonic and supersonic regimes of the mixture flow are discussed. For vibration frequencies of the system under consideration are shown that shell frequencies with big bubbles–liquids mixture exceed the frequencies of system of with small gas bubbles–liquid mixture. In subsonic regime increasing of shell thickness brings to increasing of shell frequencies, as in case of shell with pure fluid. In subsonic regime the frequencies are increasing with decreasing of the flowing velocity, on the contrary, brings to decreasing of frequencies, similar to the case of shell with the pure fluid.

  14. Simulation and Fabrication of SAW-Based Gas Sensor with Modified Surface State of Active Layer and Electrode Orientation for Enhanced H2 Gas Sensing

    Science.gov (United States)

    Hasan, Md. Nazibul; Maity, Santanu; Sarkar, Argha; Bhunia, Chandan Tilak; Acharjee, Debabrata; Joseph, Aneesh M.

    2016-11-01

    The design, analysis, optimization, and fabrication of layered and nanostructure-based surface acoustic wave (SAW) gas sensors are presented. A lithium niobate and zinc oxide (ZnO) nano multilayer structure is proposed to enhance the sensitivity of the SAW-based gas sensor. Different materials are considered for the intermediate layer in the design for optimization purposes. The sensitivity of the sensor could be improved due to increased active surface area obtained by varying the aspect ratio of the nanorods, the thickness of the intermediate layer, and the gap between the electrodes. The total displacement and frequency shift of the device were significantly improved. Overall, the mechanically engineered surface-based (nanorod) SAW gas sensor offered better sensing response than the layered SAW gas sensor in terms of sensitivity performance.

  15. Simulation and Fabrication of SAW-Based Gas Sensor with Modified Surface State of Active Layer and Electrode Orientation for Enhanced H2 Gas Sensing

    Science.gov (United States)

    Hasan, Md. Nazibul; Maity, Santanu; Sarkar, Argha; Bhunia, Chandan Tilak; Acharjee, Debabrata; Joseph, Aneesh M.

    2017-02-01

    The design, analysis, optimization, and fabrication of layered and nanostructure-based surface acoustic wave (SAW) gas sensors are presented. A lithium niobate and zinc oxide (ZnO) nano multilayer structure is proposed to enhance the sensitivity of the SAW-based gas sensor. Different materials are considered for the intermediate layer in the design for optimization purposes. The sensitivity of the sensor could be improved due to increased active surface area obtained by varying the aspect ratio of the nanorods, the thickness of the intermediate layer, and the gap between the electrodes. The total displacement and frequency shift of the device were significantly improved. Overall, the mechanically engineered surface-based (nanorod) SAW gas sensor offered better sensing response than the layered SAW gas sensor in terms of sensitivity performance.

  16. H2 Reconstitution

    Science.gov (United States)

    Skipper, Mike

    2002-02-01

    The high power microwave program at the Air Force Research Laboratory (AFRL) includes high power source development in narrow band and wideband technologies. The H2 source is an existing wideband source that was developed at the AFRL. A recent AFRL requirement for a wideband impulse generator to use in materials tests has provided the need to update the H2 source for the current test requirements. The H2 source is composed of a dual resonant transformer that charges a short length of coaxial transmission line. The transmission line is then discharged into an output coaxial transmission line with a self-break hydrogen switch. The dual resonant transformer is driven by a low inductance primary capacitor bank operating through a self-break gas switch. The upgrade of the coaxial hydrogen output switch is the focus of this report. The hydrogen output switch was developed through extensive electrical and mechanical simulations. The switch insulator is made of Ultem 2300 and is designed to operate with a mechanical factor of safety equal to 4.0 at 1,000 psi. The design criteria, design data and operational data will be presented.

  17. Research on Separation of H2 and N2 Mixed Gas with Ionic liquid Membrane%离子液膜法分离H2、N2混合气体研究

    Institute of Scientific and Technical Information of China (English)

    仲惟

    2015-01-01

    Two kinds of ionic liquid, 1-butyl 3-sold four fluoboric acid methyl imidazole salt ([BMIM]BF4) and 1-butyl 3-methyl imidazole six fluoride phosphate ([BMIM] PF6), were selected, and the ion exchange method was used to create two kinds of ionic liquid 1-butyl 3-methyl imidazole formate ([BMIM] HCOO) and 1-butyl 3-methyl imidazole acetate ([BMIM]CH3COO). Combined the advantages of ionic liquid and membrane separation, polyvinylidene fluoride, polysulfone and polyacrylonitrile membrane was chose to make ionic liquid supported liquid membrane by impregnation method. Compared the separation coefficient on different temperature of every kind of ionic liquid membrane for H2/N2 separation, it was found that the separation abilities of [BMIM] HCOO polysulfone membrane and polyacrylonitrile membrane were more bigger. The temperature conditions significantly affected the separation effect:at 30℃[BMIM]BF4 type poly-cvinylidene fluoride membrane, [BMIM]HCOO polysulfone membrane had the strong ability of H2/N2 separation, N2 could be separated off H2. 30℃in [BMIM]BF4 type polysulfone membrane separation N2/H2 ability was strong, H2 could be separated off N2.%选取2种市售离子液体1-丁基-3-甲基咪唑四氟硼酸盐([BMIM]BF4)与1-丁基-3-甲基咪唑六氟磷酸盐([BMIM]PF6),另采用离子交换法合成出2种离子液体1-丁基-3-甲基咪唑甲酸盐([BMIM]HCOO)与1-丁基-3-甲基咪唑乙酸盐([BMIM]CH3COO)。将离子液体与膜分离法优点相结合,选取聚偏氟乙烯膜、聚砜膜和聚丙烯腈膜并用浸渍法制备离子液体支撑液膜。比较不同温度下不同类型离子液膜对H2/N2的分离系数发现,[BMIM]HCOO型聚砜膜和聚丙烯腈膜对H2/N2分离系数较大。温度条件显著影响分离效果:30℃时[BMIM]BF4型聚偏氟乙烯膜、[BMIM]HCOO型聚砜膜分离H2/N2能力较强,可分离掉N2获得H2;30℃时[BMIM]BF4型聚砜膜分离N2/H2能力较强,可分离掉H2获得N2。

  18. Numerical simulation of the passive gas mixture flow

    Directory of Open Access Journals (Sweden)

    Kyncl Martin

    2016-01-01

    Full Text Available The aim of this paper is the numerical solution of the equations describing the non-stationary compressible turbulent multicomponent flow in gravitational field. The mixture of perfect inert gases is assumed. We work with the RANS equations equipped with the k-omega and the EARSM turbulence models. For the simulation of the wall roughness we use the modification of the specific turbulent dissipation. The finite volume method is used, with thermodynamic constants being functions in time and space. In order to compute the fluxes through the boundary faces we use the modification of the Riemann solver, which is the original result. We present the computational results, computed with the own-developed code (C, FORTRAN, multiprocessor, unstructured meshes in general.

  19. Use of Doehlert and constrained mixture designs in the development of a photo-oxidation procedure using UV radiation/H2O2 for decomposition of landfill leachate samples and determination of metals by flame atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Marcos A. Bezerra

    2015-03-01

    Full Text Available This work proposes the use of photo-oxidation degradation with UV radiation/H2O2 as sample treatment for the determination of Fe, Zn, Mn, Ni and Co in municipal solid waste landfill leachate by flame atomic absorption spectrometry (FAAS. Three variables (pH, irradiation time and buffer concentration were optimized using Doehlert design and the proportions of mixture components submitted to UV radiation (leachate sample, buffer solution and H2O2 30%, v/v were optimized using a constrained mixture design. Using the experimental conditions established, this procedure allows limits of detection of 0.075, 0.025, 0.010, 0.075 and 0.041 µg mL-1, and the precision levels expressed as relative standard (%RSD, 0.5 µg mL-1 were 3.6, 1.8, 1.3, 3.3 and 1.7%, for Fe, Mn, Zn, Ni and Co respectively. Recovery tests were carried out for evaluation of the procedure accuracy and recoveries were between 92 and 106% for the studied metals. This procedure has been applied for the analysis of the landfill leachate collected in Jequié, a city of the southwestern region of the State of Bahia, Brazil. The results were compared with those obtained by acid digestion. There was no significant difference between the results obtained by the two methods based on paired t-test at 95% confidence level.

  20. Infrared studies of molecular shocks in the supernova remnant HB 21: II. Thermal admixture of shocked H2 gas in the south

    Science.gov (United States)

    Shinn, Jong-Ho; Koo, Bon-Chul; Burton, Michael; Lee, Ho-Gyu; Moon, Dae-Sik

    2010-02-01

    We present near- and mid-infrared observations on the shock-cloud interaction region in the southern part of the supernova remnant HB 21, performed with the InfraRed Camera (IRC) aboard AKARI satellite and the Wide InfraRed Camera (WIRC) at the Palomar 5 m telescope. The IRC 4 μm (N4), 7 μm (S7), and 11 μm (S11) band images and the WIRC Hυ=1→0S(1) 2.12 μm image show similar diffuse features, around a shocked CO cloud. We analyzed the emission through comparison with the H2 line emission of several shock models. The IRC colors are well explained by the thermal admixture model of H2 gas - whose infinitesimal H2 column density has a power-law relation with the temperature T, dN˜T-dT - with n(H)˜3.9×104cm-3,b˜4.2, and N(H;T>100K)˜2.8×1021cm-2. We interpreted these parameters with several different pictures of the shock-cloud interactions - multiple planar C-shocks, bow shocks, and shocked clumps - and discussed their weaknesses and strengths. The observed Hυ=1→0S(1) intensity is four times greater than the prediction from the power-law admixture model, the same tendency as found in the northern part of HB 21 (Paper I). We also explored the limitation of the thermal admixture model with respect to the derived model parameters.

  1. Shape and strength of dynamical couplings between vibrational levels of the H2 +, HD+ and D2 + molecular ions in collision with He as a buffer gas

    Science.gov (United States)

    Iskandarov, Ibrokhim; Gianturco, Francesco Antonio; Vera, Mario Hernandez; Wester, Roland; da Silva, Humberto; Dulieu, Olivier

    2017-06-01

    We present a detailed computational analysis for the interaction between the vibrating/rotating molecular ions H2 +, HD+, D2 + colliding with He atoms employed as buffer gas within ion trap experiments. The production and preparation of these molecular ions from their neutrals usually generate rovibrationally excited species which will therefore require internal energy cooling down to their ground vibrational levels for further experimental handling. In this work we describe the calculation of the full 3D interaction potentials and of the ionic vibrational levels needed to obtain the vibrational coupling potential matrix elements which are needed in the multichannel treatment of the rovibrationally inelastic collision dynamics. The general features of such coupling potential terms are discussed for their employment within a quantum dynamical modeling of the relaxation processes, as well as in connection with their dependence on the initial and final vibrational levels which are directly coupled by the present potentials. As a preliminary test of the potential effects on scattering observables, we perform calculations between H2 + and He atoms at the energies of an ion-trap by using either the rigid rotor (RR) approximation or the more accurate vibrationally averaged (VA) description for the v = 0 state of the target. Both schemes are described in detail in the present paper and the differences found in the scattering results are also analysed and discussed. We further present and briefly discuss some examples of state-to-state rovibrationally inelastic cross sections, involving the two lowest vibrational levels of the H2 + molecular target ion, as obtained from our time-independent multichannel quantum scattering code.

  2. Operation of static and flowing Cs DPAL with different buffer gas mixtures

    Science.gov (United States)

    Knize, R. J.; Zhdanov, B. V.; Rotondaro, M. T.; Shaffer, M. K.

    2016-03-01

    Cs DPAL operation using Ethane, Methane and mixtures of these hydrocarbons with noble gases He and Ar as a buffer gases for spin-orbit relaxation was studied in this work. The best Cs DPAL performance in continuous wave operation with flowing gain medium was achieved using pure Methane, pure Ethane or a mixture of Ethane (minimum of 200 Torr) and He with a total buffer gas pressure of 300 torr.

  3. Sub-shock formation in Grad 10-moment equations for a binary gas mixture

    Science.gov (United States)

    Bisi, Marzia; Conforto, Fiammetta; Martalò, Giorgio

    2016-09-01

    The shock structure problem for Grad 10-moment equations for an inert binary mixture is investigated: necessary conditions for the formation of sub-shocks in fields of only one gas or of both components are rigorously obtained, and a detailed comparison with the shock-wave structure of its principal sub-system (deduced assuming vanishing viscous stress tensors) and of the equilibrium Euler sub-system is performed. Some numerical simulations for a mixture of argon and helium are presented.

  4. Effect of Gas Mixture Composition on the Parameters of an Internal Combustion Engine

    Directory of Open Access Journals (Sweden)

    Andrej Chríbik

    2012-01-01

    Full Text Available This paper deals with the use of the internal combustion piston engine, which is a drive unit for micro-cogeneration units. The introduction is a brief statement of the nature of gas mixture compositions that are useful for the purposes of combustion engines, together with the basic physical and chemical properties relevant to the burning of this gas mixture. Specifically, we will discuss low-energy gases (syngases and mixtures of natural gas with hydrogen. The second section describes the conversion of the Lombardini LGW 702 combustion engine that is necessary for these types of combustion gases. Before the experimental measurements, a simulation in the Lotus Engine simulation program was carried out to make a preliminary assessment of the impact on the performance of an internal combustion engine. The last section of the paper presents the experimental results of partial measurements of the performance and emission parameters of an internal combustion engine powered by alternative fuels.

  5. A HIFI preview of warm molecular gas around chi Cyg : first detection of H2O emission toward an S-type AGB star

    CERN Document Server

    Justtanont, K; Schoier, F L; Maercker, M; Olofsson, H; Bujarrabal, V; Marston, A P; Teyssier, D; Alcolea, J; Cernicharo, J; Dominik, C; de Koter, A; Melnick, G; Menten, K; Neufeld, D; Planesas, P; Schmidt, M; Szczerba, R; Waters, R; de Graauw, Th; Whyborn, N; Finn, T; Helmich, F; Siebertz, O; Schmulling, F; Ossenkopf, V; Lai, R

    2010-01-01

    A set of new, sensitive, and spectrally resolved, sub-millimeter line observations are used to probe the warm circumstellar gas around the S-type AGB star chi Cyg. The observed lines involve high rotational quantum numbers, which, combined with previously obtained lower-frequency data, make it possible to study in detail the chemical and physical properties of, essentially, the entire circumstellar envelope of chi Cyg. The data were obtained using the HIFI instrument aboard Herschel, whose high spectral resolution provides valuable information about the line profiles. Detailed, non-LTE, radiative transfer modelling, including dust radiative transfer coupled with a dynamical model, has been performed to derive the temperature, density, and velocity structure of the circumstellar envelope. We report the first detection of circumstellar H2O rotational emission lines in an S-star. Using the high-J CO lines to derive the parameters for the circumstellar envelope, we modelled both the ortho- and para-H2O lines. Our...

  6. COSWEETTM: A New Process to Reach Very High COS Specification on Natural Gas Treatment Combined with Selective H2S Removal

    Directory of Open Access Journals (Sweden)

    Magné-Drisch Julia

    2016-05-01

    Full Text Available COSWEETTM, developed for the treatment of COS containing natural gases, is based on a combination of deacidification with any alkanolamine solution and COS hydrolysis on a metal oxide based catalyst. Nearly complete COS conversion is reached, even at a relatively low operating temperature. Coupled with a classical sweetening unit, in which an adapted alkanolamine solvent is used in order to optimise the removal of H2S, CO2, as well as the H2S/CO2 selectivity, the high catalyst activity and the original integration of the scheme secure the COS removal at minimum extra cost. Benefits on capital and operating expenditures of the plant result both from the reduction of the absorption column and solvent flow rate and from the quality of the acid gas which has positive consequences on the design of the sulfur recovery facilities units, including Claus unit. This paper presents the complete development process approach and the results obtained on COS conversion, the model and simulation tool as well as a case study showing the advantages of coupling COSWEETTM to amine based solvent.

  7. Photoresponse and H2 gas sensing properties of highly oriented Al and Al/Sb doped ZnO thin films

    Institute of Scientific and Technical Information of China (English)

    Hannane Benelmadjat; Boubekeur Boudine; Aissa Keffous; Noureddine Gabouze

    2013-01-01

    ZnO:Al and ZnO:Al/Sb thin films have been prepared and investigated. The thin films were deposited on Si substrates by the sol-gel method. The structural, optical and electrical properties of ZnO films have been investigated by spectrophotometry, ellipsometry, X-ray diffraction and current-voltage characterizations. It is found that the films exhibit wurtzite structure with a highly c-axis orientation perpendicular to the surface of the substrate, a high reflectivity in the infrared region and a response to illumination. Furthermore, it has been found that Si/(ZnO:Al/Sb)/Al photodiode is promising in photoconduction device while Si/(ZnO:Al)/Al can be used as gas sensor responding to the low H2 concentrations.

  8. Multi Parameter Flow Meter for On-Line Measurement of Gas Mixture Composition

    Directory of Open Access Journals (Sweden)

    Egbert van der Wouden

    2015-04-01

    Full Text Available In this paper we describe the development of a system and model to analyze the composition of gas mixtures up to four components. The system consists of a Coriolis mass flow sensor, density, pressure and thermal flow sensor. With this system it is possible to measure the viscosity, density, heat capacity and flow rate of the medium. In a next step the composition can be analyzed if the constituents of the mixture are known. This makes the approach universally applicable to all gasses as long as the number of components does not exceed the number of measured properties and as long as the properties are measured with a sufficient accuracy. We present measurements with binary and ternary gas mixtures, on compositions that range over an order of magnitude in value for the physical properties. Two platforms for analyses are presented. The first platform consists of sensors realized with MEMS fabrication technology. This approach allows for a system with a high level of integration. With this system we demonstrate a proof of principle for the analyses of binary mixtures with an accuracy of 10%. In the second platform we utilize more mature steel sensor technology to demonstrate the potential of this approach. We show that with this technique, binary mixtures can be measured within 1% and ternary gas mixtures within 3%.

  9. CO2 + N2O mixture gas hydrate formation kinetics and effect of soil minerals on mixture-gas hydrate formation process

    Science.gov (United States)

    Enkh-Amgalan, T.; Kyung, D.; Lee, W.

    2012-12-01

    CO2 mitigation is one of the most pressing global scientific topics in last 30 years. Nitrous oxide (N2O) is one of the main greenhouse gases (GHGs) defined by the Kyoto Protocol and its global warming potential (GWP) of one metric ton is equivalent to 310 metric tons of CO2. They have similar physical and chemical properties and therefore, mixture-gas (50% CO2 + 50% N2O) hydrate formation process was studied experimentally and computationally. There were no significant research to reduce N20 gas and we tried to make hydrate to mitigate N20 and CO2 in same time. Mixture gas hydrate formation periods were approximately two times faster than pure N2O hydrate formation kinetic in general. The fastest induction time of mixture-gas hydrate formation observed in Illite and Quartz among various soil mineral suspensions. It was also observed that hydrate formation kinetic was faster with clay mineral suspensions such as Nontronite, Sphalerite and Montmorillonite. Temperature and pressure change were not significant on hydrate formation kinetic; however, induction time can be significantly affected by various chemical species forming under the different suspension pHs. The distribution of chemical species in each mineral suspension was estimated by a chemical equilibrium model, PHREEQC, and used for the identification of hydrate formation characteristics in the suspensions. With the experimental limitations, a study on the molecular scale modeling has a great importance for the prediction of phase behavior of the gas hydrates. We have also performed molecular dynamics computer simulations on N2O and CO2 hydrate structures to estimate the residual free energy of two-phase (hydrate cage and guest molecule) at three different temperature ranges of 260K, 273K, and 280K. The calculation result implies that N2O hydrates are thermodynamically stable at real-world gas hydrate existing condition within given temperature and pressure. This phenomenon proves that mixture-gas could be

  10. Influence of the Gas Mixture Ratio on the Correlations Between the Excimer XeCl* Emission and the Sealed Gas Temperature in Dielectric Barrier Discharge Lamps

    Institute of Scientific and Technical Information of China (English)

    徐金洲; 梁荣庆; 任兆杏

    2002-01-01

    For dielectric barrier discharge lamps filled with various gas mixture ratios, the correlations between the excimer XeCl* emission and the sealed gas temperature have been founded, and a qualitative explication is presented. For gas mixture with chlorine larger than 3%, the emission intensity increases with the sealed gas temperature, while with chlorine about 2%, the emission intensity decreases with the increase in the gas temperature, and could be improved by cooling water. However, if chlorine is less than 1.5%, the discharge appears to be a mixture mode with filaments distributed in a diffused glow-like discharge, and the UV emission is independent on the gas temperature.

  11. Numerical solution of the Boltzmann equation for the shock wave in a gas mixture

    CERN Document Server

    Raines, A A

    2014-01-01

    We study the structure of a shock wave for a two-, three- and four-component gas mixture on the basis of numerical solution of the Boltzmann equation for the model of hard sphere molecules. For the evaluation of collision integrals we use the Conservative Projection Method developed by F.G. Tscheremissine which we extended to gas mixtures in cylindrical coordinates. The transition from the upstream to downstream uniform state is presented by macroscopic values and distribution functions. The obtained results were compared with numerical and experimental results of other authors.

  12. High-precision gas gain and energy transfer measurements in Ar–CO{sub 2} mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Şahin, Özkan, E-mail: osahin@uludag.edu.tr [Department of Physics, Uludağ University, 16059 Bursa (Turkey); Kowalski, Tadeusz Z. [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Kraków (Poland); Veenhof, Rob [Department of Physics, Uludağ University, 16059 Bursa (Turkey); RD51 collaboration, CERN, Genève (Switzerland)

    2014-12-21

    Ar–CO{sub 2} is a Penning mixture since a fraction of the energy stored in Ar 3p{sup 5}3d and higher excited states can be transferred to ionize CO{sub 2} molecules. In the present work, concentration and pressure dependence of Penning transfer rate and photon feedback parameter in Ar–CO{sub 2} mixtures have been investigated with recent systematic high-precision gas gain measurements which cover the range 1–50% CO{sub 2} at 400, 800, 1200, 1800 hPa and gas gain from 1 to 5×10{sup 5}.

  13. High-precision gas gain and energy transfer measurements in Ar–CO2 mixtures

    CERN Document Server

    Şahin, Özkan; Veenhof, Rob

    2014-01-01

    Ar–CO2 is a Penning mixture since a fraction of the energy stored in Ar 3p53d3p53d and higher excited states can be transferred to ionize CO2 molecules. In the present work, concentration and pressure dependence of Penning transfer rate and photon feedback parameter in Ar–CO2 mixtures have been investigated with recent systematic high-precision gas gain measurements which cover the range 1–50% CO2 at 400, 800, 1200, 1800 hPa and gas gain from 1 to 5×105.

  14. Separation of Industrially-Relevant Gas Mixtures With Metal-Organic Frameworks

    Science.gov (United States)

    Herm, Zoey Rose

    The work herein describes the investigation of metal-organic frameworks for industrial applications, specifically gas phase separations of mixtures. Metal-organic frameworks are crystalline molecular scaffolds built from cationic metal vertices and organic bridging ligands. They are porous on a molecular scale and can separate gas mixtures when one component interacts more strongly with the pore walls than others. The near-infinite combination of metals and ligands allows for optimization of metal-organic framework structures for specific separations. (Abstract shortened by UMI.)

  15. Sulfur isotope fractionation during oxidation of sulfur dioxide: gas-phase oxidation by OH radicals and aqueous oxidation by H2O2, O3 and iron catalysis

    Directory of Open Access Journals (Sweden)

    J. N. Crowley

    2012-01-01

    Full Text Available The oxidation of SO2 to sulfate is a key reaction in determining the role of sulfate in the environment through its effect on aerosol size distribution and composition. Sulfur isotope analysis has been used to investigate sources and chemical processes of sulfur dioxide and sulfate in the atmosphere, however interpretation of measured sulfur isotope ratios is challenging due to a lack of reliable information on the isotopic fractionation involved in major transformation pathways. This paper presents laboratory measurements of the fractionation factors for the major atmospheric oxidation reactions for SO2: Gas-phase oxidation by OH radicals, and aqueous oxidation by H2O2, O3 and a radical chain reaction initiated by iron. The measured fractionation factor for 34S/32S during the gas-phase reaction is αOH = (1.0089±0.0007−((4±5×10−5 T(°C. The measured fractionation factor for 34S/32S during aqueous oxidation by H2O2 or O3 is αaq = (1.0167±0.0019−((8.7±3.5 ×10−5T(°C. The observed fractionation during oxidation by H2O2 and O3 appeared to be controlled primarily by protonation and acid-base equilibria of S(IV in solution, which is the reason that there is no significant difference between the fractionation produced by the two oxidants within the experimental error. The isotopic fractionation factor from a radical chain reaction in solution catalysed by iron is αFe = (0.9894±0.0043 at 19 °C for 34S/32S. Fractionation was mass-dependent with regards to 33S/32S for all the reactions investigated. The radical chain reaction mechanism was the only measured reaction that had a faster rate for the light isotopes. The results presented in this study will be particularly useful to determine the importance of the transition metal-catalysed oxidation pathway compared to other oxidation pathways, but other main oxidation pathways can not be distinguished based on stable sulfur isotope measurements alone.

  16. Improvement of H2S Sensing Properties of SnO2-Based Thick Film Gas Sensors Promoted with MoO3 and NiO

    Directory of Open Access Journals (Sweden)

    In Sung Son

    2013-03-01

    Full Text Available The effects of the SnO2 pore size and metal oxide promoters on the sensing properties of SnO2-based thick film gas sensors were investigated to improve the detection of very low H2S concentrations (<1 ppm. SnO2 sensors and SnO2-based thick-film gas sensors promoted with NiO, ZnO, MoO3, CuO or Fe2O3 were prepared, and their sensing properties were examined in a flow system. The SnO2 materials were prepared by calcining SnO2 at 600, 800, 1,000 and 1,200 °C to give materials identified as SnO2(600, SnO2(800, SnO2(1000, and SnO2(1200, respectively. The Sn(12Mo5Ni3 sensor, which was prepared by physically mixing 5 wt% MoO3 (Mo5, 3 wt% NiO (Ni3 and SnO2(1200 with a large pore size of 312 nm, exhibited a high sensor response of approximately 75% for the detection of 1 ppm H2S at 350 °C with excellent recovery properties. Unlike the SnO2 sensors, its response was maintained during multiple cycles without deactivation. This was attributed to the promoter effect of MoO3. In particular, the Sn(12Mo5Ni3 sensor developed in this study showed twice the response of the Sn(6Mo5Ni3 sensor, which was prepared by SnO2(600 with the smaller pore size than SnO2(1200. The excellent sensor response and recovery properties of Sn(12Mo5Ni3 are believed to be due to the combined promoter effects of MoO3 and NiO and the diffusion effect of H2S as a result of the large pore size of SnO2.

  17. Diffusion of relativistic gas mixtures in gravitational fields

    CERN Document Server

    Kremer, Gilberto M

    2013-01-01

    A mixture of relativistic gases of non-disparate rest masses in a Schwarzschild metric is studied on the basis of a relativistic Boltzmann equation in the presence of gravitational fields. A BGK-type model equation of the collision operator of the Boltzmann equation is used in order to compute the non-equilibrium distribution functions by the Chapman-Enskog method. The main focus of this work is to obtain Fick's law without the thermal-diffusion cross-effect. Fick's law has four contributions, two of them are the usual terms proportional to the gradients of concentration and pressure. The other two are of the same nature as those which appears in Fourier's law in the presence of gravitational fields and are related with an acceleration and gravitational potential gradient, but unlike Fourier's law these two last terms are of non-relativistic order. Furthermore, it is shown that the coefficients of diffusion depend on the gravitational potential and they become larger than those in the absence of it.

  18. Exploiting mixtures of H2, CO2, and O2 for improved production of methacrylate precursor 2-hydroxyisobutyric acid by engineered Cupriavidus necator strains.

    Science.gov (United States)

    Przybylski, Denise; Rohwerder, Thore; Dilßner, Cornelia; Maskow, Thomas; Harms, Hauke; Müller, Roland H

    2015-03-01

    Current manufacturing of most bulk chemicals through petrochemical routes considerably contributes to common concerns over the depletion of fossil carbon sources and greenhouse gas emissions. Sustainable future production of commodities thus requires the shift to renewable feedstocks in combination with established or newly developed synthesis routes. In this study, the potential of Cupriavidus necator H16 for autotrophic synthesis of the building block chemical 2-hydroxyisobutyric acid (2-HIBA) is evaluated. A novel biosynthetic pathway was implemented by heterologous expression of the 2-hydroxyisobutyryl-coenzyme A (2-HIB-CoA) mutase from Aquincola tertiaricarbonis L108, relying on a main intermediate of strain H16's C4 overflow metabolism, 3-hydroxybutyryl-CoA. The intention was to direct the latter to 2-HIBA instead or in addition to poly-3-hydroxybutyrate (PHB). Autotrophic growth and 2-HIBA (respectively, PHB) synthesis of wild-type and PHB-negative mutant strains were investigated producing maximum 2-HIBA titers of 3.2 g L(-1) and maximum specific 2-HIBA synthesis rates (q 2-HIBA) of about 16 and 175 μmol g(-1) h(-1), respectively. The obtained specific productivity was the highest reported to date for mutase-dependent 2-HIBA synthesis from heterotrophic and autotrophic substrates. Furthermore, expression of a G protein chaperone (MeaH) in addition to the 2-HIB-CoA mutase subunits yielded improved productivity. Analyzing the inhibition of growth and product synthesis due to substrate availability and product accumulation revealed a strong influence of 2-HIBA, when cells were cultivated at high titers. Nevertheless, the presented results imply that at the time the autotrophic synthesis route is superior to thus far established heterotrophic routes for production of 2-HIBA with C. necator.

  19. Breakdown Voltage Research of Penning Gas Mixture in Plasma Display Panel

    Institute of Scientific and Technical Information of China (English)

    Guo Bingang; Liu Chunliang; Song Zhongxiao; Fan Yufeng; Xia Xing; Liu Liu; Fan Duowang

    2005-01-01

    Paschen law and equations, which ignore the influence of the Penning ionization on the electron ionization coefficient (α), are always used as the approximation of the breakdown voltage criterion of the Penning gas mixture in current researches of discharge characteristics of the plasma display panel (PDP). It is doubtful that whether their results match the facts. Based on the Townsend gas self-sustaining discharge condition and the chemical kinetics analysis of the Penning gas mixture discharging in PDP, the empirical equation to describe the breakdown of the Penning gas mixture is given. It is used to calculate the breakdown voltage curves of Ne-Xe/MgO and Ne-Ar/MgO in a testing macroscopic discharge cell of AC-PDP. The effective secondary electron emission coefficients (γeff) of the MgO protective layers are derived by comparing the breakdown voltage curves obtained from the empirical equation with the experimental data of breakdown voltages. In comparison with the results calculated by the Paschen law and the equation which ignore the influence of the Penning ionization on α , the results calculated by the empirical equation have better conformity with experimental data. The empirical equation characterizes the breakdown of the Penning gas mixture in PDP effectively, and gives a convenient way to study its breakdown characteristics and the secondary electron emission behaviors.

  20. Effect of H2S Flow Rate and Concentration on Performance of H2S/Air Solid Oxide Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    钟理; 张腾云; 陈建军; WEIGuolin; LUOJingli; K.Chung

    2004-01-01

    A solid state H2S/air electrochemical cell having the configuration of H2S, (MoS2+NiS+Ag)/YSZ/Pt,air has been examined with different H2S flow rates and concentrations at atmospheric pressure and 750-850℃.Performance of the fuel cell was dependent on anode compartment H2S flow rate and concentration. The cell open-circuit voltage increased with increasing H2S flow rate. It was found that increasing both H2S flow rate and H2S concentration improved current-voltage and power density performance. This is resulted from improved gas diffusion in anode and increased concentration of anodic electroactive species. Operation at elevated H2S concentration improved the cell performance at a given gas flow rate. However, as low as 5% H2S in gas mixture can also be utilized as fuel feed to cells. Highest current and power densities, 1750mA·cm-2 and 200mW·cm-2,are obtained with pure H2S flow rate of 50 ml·min-1 and air flow rate of 100ml·min-1 at 850℃.

  1. 高含H2S天然气偏差系数计算新模型%New Model for Calculation of H2S-Rich Natural Gas Deviation Factor

    Institute of Scientific and Technical Information of China (English)

    卞小强; 杜志敏; 汤勇

    2010-01-01

    根据里群等实测的高含H2S天然气偏差系数Z值,利用非整数幂多项式拟合方法,建立了新的高含H2S天然气偏差系数计算模型.利用新模型和Dranchuk-Abu-Kassem-Wichert-Aziz(DAK-W-A)模型对实测偏差系数进行了拟合计算.与实验值对比结果表明,新模型平均相对误差为0.276%,最大相对误差为2.734%,精度明显高于DAK-W-A模型,且具有计算快速、容易进行微分积分运算等特点.

  2. A First Principle Comparative Study on Chemisorption of H2 on C60, C80, and Sc3N@C80 in Gas Phase and Chemisorption of H2 on Solid Phase C60

    Directory of Open Access Journals (Sweden)

    Hongtao Wang

    2014-01-01

    Full Text Available The chemisorptions of H2 on fullerenes C60 and C80, endofullerene Sc3C@C80 and solid C60 were comparatively studied. A chain reaction mechanism for dissociative adsorption of H2 on solid C60 is proposed under high pressure. The breaking of H–H bond is concerted with the formation of two C–H bonds on two adjacent C60 in solid phase. The adsorption process is facilitated by the application of high pressure. The initial H2 adsorption on two adjacent C60 gives a much lower barrier 1.36 eV in comparison with the barrier of adsorption on a single C60 (about 3.0 eV. As the stereo conjugate aromaticity of C60 is destructed by the initial adsorption, some active sites are created. Hence the successive adsorption becomes easier with much low barriers (0.6 eV. In addition, further adsorption can create new active sites for the next adsorption. Thus, a chain reaction path is formed with the initial adsorption dominating the whole adsorption process.

  3. Investigation of the helium proportion influence on the Prandtl number value of gas mixtures

    Directory of Open Access Journals (Sweden)

    S. A. Burtsev

    2014-01-01

    Full Text Available The paper investigates an influence of helium fraction (light gases on the Prandtl number value for binary and more complex gas mixtures.It is shown that a low value of the Prandtl number (Pr-number results in decreasing a temperature recovery factor value and, respectively, in reducing a recovery temperature value on the wall (thermoinsulated wall temperature with the compressive gas flow bypassing it. This, in turn, allows us to increase efficiency of gasdynamic energy separation in Leontyev's tube.The paper conducts a numerical research of the influence of binary and more complex gas mixture composition on the Prandtl number value. It is shown that a mixture of two gases with small and large molecular weight allows us to produce a mixture with a lower value of the Prandtl number in comparison with the initial gases. Thus, the value of Prandtl number decreases by 1.5-3.2 times in comparison with values for pure components (the more a difference of molar mass of components, the stronger is a decrease.The technique to determine the Prandtl number value for mixtures of gases in the wide range of temperatures and pressure is developed. Its verification based on experimental data and results of numerical calculations of other authors is executed. It is shown that it allows correct calculation of binary and more complex mixtures of gasesFor the mixtures of inert gases it has been obtained that the minimum value of the Prandtl number is as follows: for helium - xenon mixtures (He-Xe makes 0.2-0.22, for helium - krypton mixtures (He-Kr – 0.3, for helium - argon mixes (He-Ar – 0.41.For helium mixture with carbon dioxide the minimum value of the Prandtl number makes about 0.4, for helium mixture with N2 nitrogen the minimum value of the Prandtl number is equal to 0.48, for helium-methane (CH4 - 0.5 and helium – oxygen (O2 – 0.46.This decrease is caused by the fact that the thermal capacity of mixture changes under the linear law in regard to the

  4. Thick c-BN films deposited by radio frequency magnetron sputtering in argon/nitrogen gas mixture with additional hydrogen gas

    Science.gov (United States)

    Zhao, Yan; Gao, Wei; Xu, Bo; Li, Ying-Ai; Li, Hong-Dong; Gu, Guang-Rui; Yin, Hong

    2016-10-01

    The excellent physical and chemical properties of cubic boron nitride (c-BN) film make it a promising candidate for various industry applications. However, the c-BN film thickness restricts its practical applications in many cases. Thus, it is indispensable to develop an economic, simple and environment-friend way to synthesize high-quality thick, stable c-BN films. High-cubic-content BN films are prepared on silicon (100) substrates by radio frequency (RF) magnetron sputtering from an h-BN target at low substrate temperature. Adhesions of the c-BN films are greatly improved by adding hydrogen to the argon/nitrogen gas mixture, allowing the deposition of a film up to 5-μm thick. The compositions and the microstructure morphologies of the c-BN films grown at different substrate temperatures are systematically investigated with respect to the ratio of H2 gas content to total working gas. In addition, a primary mechanism for the deposition of thick c-BN film is proposed. Project supported by the National Natural Science Foundation of China (Grant Nos. 51572105, 61504046, and 51272224), the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry, China, the Development and Reform Commission of Jilin Province, China (Grant No. 2015Y050), and the Scientific Research Foundation for the Returned Overseas of Jilin Province, China.

  5. Effective diffusion coefficients of gas mixture in heavy oil under constant-pressure conditions

    Science.gov (United States)

    Li, Huazhou Andy; Sun, Huijuan; Yang, Daoyong

    2016-09-01

    We develop a method to determine the effective diffusion coefficient for each individual component of a gas mixture in a non-volatile liquid (e.g., heavy oil) at high pressures with compositional analysis. Theoretically, a multi-component one-way diffusion model is coupled with the volume-translated Peng-Robinson equation of state to quantify the mass transfer between gas and liquid (e.g., heavy oil). Experimentally, the diffusion tests have been conducted with a PVT setup for one pure CO2-heavy oil system and one C3H8-CO2-heavy oil system under constant temperature and pressure, respectively. Both the gas-phase volume and liquid-phase swelling effect are simultaneously recorded during the measurement. As for the C3H8-CO2-heavy oil system, the gas chromatography method is employed to measure compositions of the gas phase at the beginning and end of the diffusion measurement, respectively. The effective diffusion coefficients are then determined by minimizing the discrepancy between the measured and calculated gas-phase composition at the end of diffusion measurement. The newly developed technique can quantify the contributions of each component of mixture to the bulk mass transfer from gas into liquid. The effective diffusion coefficient of C3H8 in the C3H8-CO2 mixture at 3945 ± 20 kPa and 293.85 K, i.e., 18.19 × 10^{ - 10} m^{ 2} / s, is found to be much higher than CO2 at 3950 ± 18 kPa and 293.85 K, i.e., 8.68 × 10^{ - 10} m^{ 2} / s. In comparison with pure CO2, the presence of C3H8 in the C3H8-CO2 mixture contributes to a faster diffusion of CO2 from the gas phase into heavy oil and consequently a larger swelling factor of heavy oil.

  6. Investigation of Dalton and Amagat's laws for gas mixtures with shock propagation

    Science.gov (United States)

    Wayne, Patrick; Trueba Monje, Ignacio; Yoo, Jason H.; Truman, C. Randall; Vorobieff, Peter

    2016-11-01

    Two common models describing gas mixtures are Dalton's Law and Amagat's Law (also known as the laws of partial pressures and partial volumes, respectively). Our work is focused on determining the suitability of these models to prediction of effects of shock propagation through gas mixtures. Experiments are conducted at the Shock Tube Facility at the University of New Mexico (UNM). To validate experimental data, possible sources of uncertainty associated with experimental setup are identified and analyzed. The gaseous mixture of interest consists of a prescribed combination of disparate gases - helium and sulfur hexafluoride (SF6). The equations of state (EOS) considered are the ideal gas EOS for helium, and a virial EOS for SF6. The values for the properties provided by these EOS are then used used to model shock propagation through the mixture in accordance with Dalton's and Amagat's laws. Results of the modeling are compared with experiment to determine which law produces better agreement for the mixture. This work is funded by NNSA Grant DE-NA0002913.

  7. Diffusion membrane and process for separating hydrogen from gas mixture

    Energy Technology Data Exchange (ETDEWEB)

    Behr, F.; Schulten, R.; Weirich, W.

    1985-01-29

    For separation of hydrogen and its isotopes by diffusion through a membrane virtually impermeable to other gases, a non-porous hydrogen-permeable metallic membrane is provided on the gas access side with a coating of an alloy of palladium with at least 45 atomic % Cu or at least 50 atomic percent Ag or at least 7 atomic % Y, the membrane itself containing Cu, Ag or Y respectively in a concentration at least equilibrated with the coating at operation temperature. Preferably the membrane consists of a metal of niobium and/or tantalum bases especially of an alloy containing from 10 to 30 % Ti, 3 to 10 % V, 0 to 25 % Nb and at least 30 % Ta, all by weight, and preferably it is of a composition of 20 to 25 % Ti, 5 to 7,5 % V, 0 to 25 Nb, and at least 50 % Ta, being saturated with copper and or silver, while a copper and/or silver palladium alloy coating is used. Such inherently oxidation sensitive membranes can be stabilized by provision of an internal intermediate layer in the form of a melt forming or containing an alkaline metal hydride and/or an alkaline earth metal hydride. A melt containing alkaline metal and/or alkaline earth metal which forms a hydride, brought into contact on the secondary side of a membrane in accordance with the invention, provides a hydrogen sink on the secondary side and inhibits internal hydride formation and secondary side oxidation of the membrane.

  8. Ideal gas solubilities and solubility selectivities in a binary mixture of room-temperature ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Finotello Alexia; Bara Jason E.; Narayan Suguna; Campder Dean; Noble Richard D. [University of Colorado, Boulder, CO (United States)

    2008-07-01

    This study focuses on the solubility behaviors of CO{sub 2}, CH{sub 4}, and N{sub 2} gases in binary mixtures of imidazolium-based room-temperature ionic liquids (RTILs) using l-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)-imide ((C{sub 2}mim)(Tf{sub 2}N)) and l-ethyl-3-methylimidazolium tetrafluoroborate ((C{sub 2}mim)(BF{sub 4})) at 40{sup o}C and low pressures (about 1 atm). The mixtures tested were 0, 25, 50, 75, 90, 95, and 100 mol % (C{sub 2}mim)(BF{sub 4}) in (C{sub 2}-mim)(Tf2{sub N}). Results show that regular solution theory (RST) can be used to describe the gas solubility and selectivity behaviors in RTIL mixtures using an average mixture solubility parameter or an average measured mixture molar volume. Interestingly, the solubility selectivity, defined as the ratio of gas mole fractions in the RTIL mixture, of CO{sub 2} with N{sub 2} or CH{sub 4} in pure (C{sub 2}mim)(BF4) can be enhanced by adding 5 mol% (C{sub 2}-mim)(Tf{sub 2}N).

  9. Ideal gas solubilities and solubility selectivities in a binary mixture of room-temperature ionic liquids.

    Science.gov (United States)

    Finotello, Alexia; Bara, Jason E; Narayan, Suguna; Camper, Dean; Noble, Richard D

    2008-02-28

    This study focuses on the solubility behaviors of CO2, CH4, and N2 gases in binary mixtures of imidazolium-based room-temperature ionic liquids (RTILs) using 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][Tf2N]) and 1-ethyl-3-methylimidazolium tetrafluoroborate ([C2mim][BF4]) at 40 degrees C and low pressures (approximately 1 atm). The mixtures tested were 0, 25, 50, 75, 90, 95, and 100 mol % [C2mim][BF4] in [C2mim][Tf2N]. Results show that regular solution theory (RST) can be used to describe the gas solubility and selectivity behaviors in RTIL mixtures using an average mixture solubility parameter or an average measured mixture molar volume. Interestingly, the solubility selectivity, defined as the ratio of gas mole fractions in the RTIL mixture, of CO2 with N2 or CH4 in pure [C2mim][BF4] can be enhanced by adding 5 mol % [C2mim][Tf2N].

  10. New SI-traceable reference gas mixtures for fluorinated gases at atmospheric concentration

    Science.gov (United States)

    Guillevic, Myriam; Wyss, Simon A.; Pascale, Céline; Vollmer, Martin K.; Niederhauser, Bernhard; Reimann, Stefan

    2016-04-01

    In order to better support the monitoring of greenhouse gases in the atmosphere, we develop a method to produce reference gas mixtures for fluorinated gases (F-gases, i.e. gases containing fluorine atoms) in a SI-traceable way, meaning that the amount of substance fraction in mole per mole is traceable to SI-units. These research activities are conducted in the framework of the HIGHGAS and AtmoChem-ECV projects. First, single-component mixtures in synthetic air at ~85 nmol/mol (ppb) are generated for HFC-125 (pentafluoroethane, a widely used HFC) and HFC-1234yf (2,3,3,3-tetrafluoropropene, a car air conditioner fluid of growing importance). These mixtures are first dynamically produced by permeation: a permeator containing the pure substance loses mass linearly over time under a constant gas flow, in the permeation chamber of a magnetic suspension balance, which is regularly calibrated. This primary mixture is then pressurised into Silconert2000-coated stainless steel cylinders by cryo-filling. In a second step these mixtures are dynamically diluted using 2 subsequent dilution steps piloted by mass flow controllers (MFC) and pressure controllers. The assigned mixture concentration is calculated mostly based on the permeator mass loss, on the carrier gas purity and on the MFCs flows. An uncertainty budget is presented, resulting in an expanded uncertainty of 2% for the HFC-125 reference mixture and of 2.5% for the HFC-1234yf mixture (95% confidence interval). The final gas, with near-atmospheric concentration (17.11 pmol/mol for HFC-125, 2.14 pmol/mol for HFC-1234yf) is then measured with Medusa-GC/MS technology against standards calibrated on existing reference scales. The assigned values of the dynamic standards are in excellent agreement with measurements vs the existing reference scales, SIO-14 from the Scripps Institution of Oceanography for HFC-125 and Empa-2013 for HFC-1234yf. Moreover, the Medusa-GC/MS measurements show the excellent purity of the SI

  11. Anisotropic collision-induced Raman scattering by the Kr:Xe gas mixture.

    Science.gov (United States)

    Dixneuf, S; Chrysos, M; Rachet, F

    2009-08-21

    We report anisotropic collision-induced Raman scattering intensities by the Kr-Xe atomic pair recorded in a gas mixture of Kr and Xe at room temperature. We compare them to quantum-mechanical calculations on the basis of modern incremental polarizability models of either ab initio post-Hartree-Fock or density functional theory methods.

  12. Concentration measurement systems with stable solutions for binary gas mixtures using two flowmeters

    Science.gov (United States)

    Youn, Chongho; Kawashima, Kenji; Kagawa, Toshiharu

    2011-06-01

    The previously proposed gas concentration measurement system (Yamazaki et al 2007 Meas. Sci. Technol. 18 2762-8) shows a considerable error for some combinations of gases. The error increases when the system of equations determining mole fractions becomes a mathematically ill-conditioned system. Because the parameters of the equations reflect the material properties of the gases, the current paper considers flowmeters whose flow rate indication does not involve any gas property. This paper firstly illustrates the ill condition for the combination of venturi meter and laminar flowmeters. The paper then discusses the simultaneous measurement of flow rate and mole fractions by flowmeter combinations: an ultrasonic flowmeter and a venturi meter, an ultrasonic flowmeter and a laminar flowmeter. Experiments are conducted for a mixture of argon and air. When a venturi meter and a laminar flowmeter are used, the equations to evaluate the gas mixture ratio become an ill-conditioned system, and hence the evaluated mixture ratio shows a considerable error. On the other hand, the combination of an ultrasonic flowmeter and a laminar flowmeter detects the gas mixture ratio with proper accuracy.

  13. Effect of precursor and preparation method on manganese based activated carbon sorbents for removing H2S from hot coal gas.

    Science.gov (United States)

    Wang, Jiancheng; Qiu, Biao; Han, Lina; Feng, Gang; Hu, Yongfeng; Chang, Liping; Bao, Weiren

    2012-04-30

    Activated carbon (AC) supported manganese oxide sorbents were prepared by the supercritical water impregnation (SCWI) using two different precursor of Mn(NO(3))(2) (SCW(N)) and Mn(Ac)(2)·4H(2)O (SCW(A)). Their capacities of removing H(2)S from coal gas were evaluated and compared to the sorbents prepared by the pore volume impregnation (PVI) method. The structure and composition of different sorbents were characterized by XRD, SEM, TEM, XPS and XANES techniques. It is found that the precursor of active component plays the crucial role and SCW(N) sorbents show much better sulfidation performance than the SCW(A) sorbents. This is because the Mn(3)O(4) active phase of the SCW(N) sorbents are well dispersed on the AC support, while the Mn(2)SiO(4)-like species in the SCW(A) sorbent can be formed and seriously aggregated. The SCW(N) sorbents with 2.80% and 5.60% manganese are favorable for the sulfidation reaction, since the Mn species are better dispersed on the SCW(N) sorbents than those on the PV(N) sorbents and results in the better sulfidation performance of the SCW(N) sorbents. As the Mn content increases to 11.20%, the metal oxide particles on AC supports aggregate seriously, which leads to poorer sulfidation performance of the SCW(N)11.20% sorbents than that of the PV(N)11.20% sorbents. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Hydrocracking of vacuum gas oil-vegetable oil mixtures for biofuels production.

    Science.gov (United States)

    Bezergianni, Stella; Kalogianni, Aggeliki; Vasalos, Iacovos A

    2009-06-01

    Hydrocracking of vacuum gas oil (VGO)--vegetable oil mixtures is a prominent process for the production of biofuels. In this work both pre-hydrotreated and non-hydrotreated VGO are assessed whether they are suitable fossil components in a VGO-vegetable oil mixture as feed-stocks to a hydrocracking process. This assessment indicates the necessity of a VGO pre-hydrotreated step prior to hydrocracking the VGO-vegetable oil mixture. Moreover, the comparison of two different mixing ratios suggests that higher vegetable oil content favors hydrocracking product yields and qualities. Three commercial catalysts of different activity are utilized in order to identify a range of products that can be produced via a hydrocracking route. Finally, the effect of temperature on hydrocracking VGO-vegetable oil mixtures is studied in terms of conversion and selectivity to diesel, jet/kerosene and naphtha.

  15. SYNTHESIS AND CHARACTERIZATION OF γ-Mo2N WITH HIGH SURFACE AREA IN THE MIXTURES OF N2/H2%合成大比表面γ-Mo2N的新方法

    Institute of Scientific and Technical Information of China (English)

    柳云骐; 刘晨光; 阙国和

    1999-01-01

    The production of high specific surface area γ-Mo2N (up to 165 m2.g-1, passivated) by temperature programmed reaction of MoO3 with mixtures of N2 and H2 was reported. The synthetic condition of high surface area γ-Mo2N (usually, SBET>100 m2.g-1) were quite difficult and the amount of starting material MoO3 in each batch was much less than 0.5 gram. However, some synthetic conditions had been greatly improved in our experiments. The crystalline phase and specific surface area had been characterized by XRD and BET. The XRD gave some information for reaction mechanism.

  16. Sudden discharge of gas mixture in a confined multi-compartment

    Energy Technology Data Exchange (ETDEWEB)

    Paladino, D.; Mignot, G.; Erkan, N.; Zboray, R.; Kapulla, R.; Andreani, M. [Paul Scherrer Inst., Laboratory for Thermal Hydraulics, Nuclear Energy and Safety Research Dept., Villigen PSI (Switzerland)

    2011-07-01

    The paper presents the results of a series of tests in the PANDA facility, performed within the OECD/SETH-2 project, focusing on the evolution of gas distribution in one subdivided compartment resulting from the sudden opening of a connection with a second compartment initially at higher pressure and filled with a mixture of different composition. This situation occurs in the case of the sudden opening of a rupture disk (or hatches) - and could be related to the EPR design. Gas transport mixing and distribution within the containment compartments is driven by the pressure difference between the volumes in the early phase of the test, and by temperature gradient and gas mixture concentration difference after that the pressure between the vessels has been equalized. The analysis performed with GOTHIC code and presented in this paper aims at complementing the interpretation of the physical phenomena taking place during the test evolution and inferred from the measurement results. (author)

  17. Discharge instabilities in high-pressure helium-fluorine laser gas mixtures

    Science.gov (United States)

    Mathew, D.; Bastiaens, H. M. J.; Peters, Peter J. M.; Boller, Klaus-Jochen

    2005-03-01

    Discharge instabilities in F2 based excimer gas lasers are investigated using a small-scale discharge system. After preionizing the gas volume, a fast rising voltage pulse initiates the discharge. The temporal development of the discharge is monitored via its fluorescence by an intensified CCD camera with a gating time of 10 ns. Homogeneous discharges are produced in gas mixtures of He/1mbar F2 and He/1mbar F2/30mbar Xe at a total pressure of 2 bar for pump pulse duratins up to 70 ns (FWHM). The addition of Xe to He/F2 mixture does not lead to discharge instabilities while the introduction of more F2 results in hotspot and filament formation.

  18. Development of a real-time absorption method for detecting the mercaptan odorizing mixture of natural gas

    NARCIS (Netherlands)

    Kireev, SV; Petrov, NG; Podolyako, EM; Shnyrev, SL

    2005-01-01

    The absorption of mercaptan mixtures used for odorizing natural gas and mixtures of natural gas is experimentally studied in the spectral range 2.5-20 mu m. An absorption method for the real-time detection of the odorant concentration is proposed. The method is based on intensity measurements of the

  19. Binary and ternary gas mixtures with temperature enhanced diffuse glow discharge characteristics for use in closing switches

    Science.gov (United States)

    Christophorou, Loucas G.; Hunter, Scott R.

    1990-01-01

    An improvement to the gas mixture used in diffuse glow discharge closing switches is disclosed which includes binary and ternary gas mixtures which are formulated to exhibit decreasing electron attachment with increasing temperature. This increases the efficiency of the conductance of the glow discharge and further inhibits the formation of an arc.

  20. On-farm Euthanasia of Broiler Chickens: Effects of Different Gas Mixtures on behavior and brain activity

    NARCIS (Netherlands)

    Gerritzen, M.A.; Lambooij, E.; Reimert, H.G.M.; Stegeman, J.A.; Spruijt, B.M.

    2004-01-01

    The purpose of this study was to investigate the suitability of gas mixtures for euthanasia of groups of broilers in their housing by increasing the percentage of CO2. The suitability was assessed by the level of discomfort before loss of consciousness, and the killing rate. The gas mixtures injecte

  1. Bubbling behaviors induced by gas-liquid mixture permeating through a porous medium

    Science.gov (United States)

    Hu, Liang; Li, Mingbo; Chen, Wenyu; Xie, Haibo; Fu, Xin

    2016-08-01

    This paper investigates the bubbling behaviors induced by gas-liquid mixture permeating through porous medium (PM), which was observed in developing immersion lithography system and was found having great differences with traditional bubbling behaviors injected with only gas phase through the PM. An experimental setup was built up to investigate the bubbling characteristics affected by the mixed liquid phase. Both the flow regimes of gas-liquid mixture in micro-channel (upstream of the PM) and the bubbling flow regimes in water tank (downstream of the PM) were recorded synchronously by high-speed camera. The transitions between the flow regimes are governed by gas and liquid Weber numbers. Based on the image analysis, the characteristic parameters of bubbling region, including the diameter of bubbling area on PM surface, gas-phase volume flux, and dispersion angle of bubbles in suspending liquid, were studied under different proportions of gas and liquid flow rate. Corresponding empirical correlations were developed to describe and predict these parameters. Then, the pertinent bubble characteristics in different bubbling flow regimes were systematically investigated. Specifically, the bubble size distribution and the Sauter mean diameter affected by increasing liquid flow rate were studied, and the corresponding analysis was given based on the hydrodynamics of bubble-bubble and bubble-liquid interactions. According to dimensionless analysis, the general prediction equation of Sauter mean diameter under different operating conditions was proposed and confirmed by experimental data. The study of this paper is helpful to improve the collection performance of immersion lithography and aims to reveal the differences between the bubbling behaviors on PM caused by only gas flow and gas-liquid mixture flow, respectively, for the researches of fluid flow.

  2. Gas Evolution Quantitative Analysis at a Temperature of 900°C of a Cellulose Mixture Modified by Mineral Additives

    Directory of Open Access Journals (Sweden)

    Zawieja Z.

    2016-06-01

    Full Text Available This article presents a gas evolution study of a novel, cellulose-based mixture with such mineral additives as expanded perlite, expanded vermiculite and microspheres. Inorganic alumina-silica binder was used to produce an uniform, bound mixture. The results have shown that the novel, cellulose-based mixture, obtained from waste paper, with mineral additives, emits smaller amounts of gas, while retaining the same thermal resistance.

  3. Gas Evolution Quantitative Analysis at a Temperature of 900°C of a Cellulose Mixture Modified by Mineral Additives

    OpenAIRE

    Zawieja Z.; Sawicki J.

    2016-01-01

    This article presents a gas evolution study of a novel, cellulose-based mixture with such mineral additives as expanded perlite, expanded vermiculite and microspheres. Inorganic alumina-silica binder was used to produce an uniform, bound mixture. The results have shown that the novel, cellulose-based mixture, obtained from waste paper, with mineral additives, emits smaller amounts of gas, while retaining the same thermal resistance.

  4. Morphology, structure, and properties of Cu-poor and Cu-rich Cu(In,Ga)Se2 films partially selenized using H2Se gas

    Science.gov (United States)

    Han, Anjun; Huang, Yongliang; Liu, Xiaohui; Xian, Wang; Meng, Fanying; Liu, Zhengxin

    2016-11-01

    Cu-poor and Cu-rich metallic precursors were prepared by cosputtering from In and Cu-Ga alloy targets and then partially selenized using H2Se gas. The properties of Cu(In,Ga)Se2 (CIGS) films are comparatively studied and the phase transition process is analyzed. The cosputtered metallic precursor has a rough morphology mostly covered by large In-rich nodules. After selenization, a large number of crumblike InSe grains were formed from the nodules on the surface of the Cu-rich film, whereas the Cu-poor film shows a dense surface. The selenized films comprise CIGS, Cu9(In,Ga)4 intermetallic, and the InSe phases. The proportion of the Cu9(In,Ga)4 phase in the Cu-rich film is more than that in the Cu-poor film. After annealing, the residual Cu9(In,Ga)4 of the Cu-poor film is eliminated. A negligible effect of Cu/(In+Ga) on the grain size can be observed. The CIGS solar cell with an efficiency of 15.1% was prepared by this method.

  5. ON THE SYNTHESIS OF MOLYBDENUM CARBIDE WITH COBALT ADDITION VIA GAS-SOLID REACTIONS IN A CH4/H2 ATMOSPHERE

    Directory of Open Access Journals (Sweden)

    C. P. B. Araujo

    Full Text Available Abstract Due to ever more severe environmental regulations regarding SOx, NOx and other pollutants' emissions, there has been an interest in developing new and improved catalysts for hydroprocessing reactions. Mo2C has been reported to display good selectivity and activity for those reactions, especially for HDS. Addition of another metal to the carbide structure may improve catalytic properties. Mo2C with low cobalt addition (2.5 and 5% was obtained via gas-solid reaction in a fixed bed reactor with CH4 (5%/H2 atmosphere. XRD and TG/DTA analysis of the precursors were carried out in order to understand its mass loss profile, doping metal presence and phase distributions. CoMoO4 as well as MoO3 were identified after calcining doped precursors at 600 °C/180min. SEM, XRD, XRF, TOC, BET and laser granulometric analysis of the reaction products were also performed. Compositions verified by XRF and theoretical values were compatible. At 700 °C both carbide (Mo2C and oxide (MoO2 phases are present, as identified in XRD analysis and observed by SEM. At 750 °C only single phase Mo2C was verified by XRD, indicating Co dispersion on the carbide matrix. Morphology at this temperature is compatible with pure Mo2C, though XRF indicates Co presence on the material.

  6. 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.

  7. Stability assessment of gas mixtures containing terpenes at nominal 5 nmol/mol contained in treated aluminum gas cylinders.

    Science.gov (United States)

    Rhoderick, George C

    2010-10-01

    Studies of climate change increasingly recognize the diverse influences exerted by terpenes in the atmosphere, including roles in particulates, ozone formation, and their oxidizing potential. Measurements of key terpenes suggest atmospheric concentrations ranging from low pmol/mol (parts per trillion) to nmol/mol (parts per billion), depending on location and compound. To accurately establish concentration trends, assess the role of terpenes in atmospheric chemistry, and relate measurement records from many laboratories and researchers, it is essential to have good calibration standards. The feasibility of preparing well-characterized, stable gas cylinder standards for terpenes at the nmol/mol level is not yet well established. Several of the world's National Metrology Institutes (NMIs) are researching the feasibility of developing primary and secondary reference gas standards at the nmol/mol level for terpenes. The US NMI, the National Institute of Standards and Technology, has prepared several nmol/mol mixtures, in treated aluminum gas cylinders, containing terpenes in dry nitrogen at nominal 5 nmol/mol for stability studies. Overall, 11 terpenes were studied for stability. An initial gas mixture containing nine terpenes, one oxygenate, and six aromatic compounds, including benzene as an internal standard, was prepared. Results for four of the nine terpenes in this initial mixture indicate stability in these treated aluminum gas cylinders for over 6 months and project long term (years) stability. Interesting results were seen for beta-pinene, which when using a linear equation rate decline predicts that it will reach a zero concentration level at day 416. At the same time, increases in alpha-pinene, D: -limonene (R-(+)-limonene), and p-cymene were observed, including camphene, a terpene not prepared in the gas mixture, indicating a chemical transformation of beta-pinene to these species. Additional mixtures containing combination of either alpha-pinene, camphor

  8. Thermophysical properties of CF4/O2 and SF6/O2 gas mixtures

    Science.gov (United States)

    Damyanova, M.; Hohm, U.; Balabanova, E.; Barton, D.

    2016-03-01

    Fitting formulae are presented for the calculation of the second interaction virial coefficients, mixture viscosities and binary diffusion coefficients for CF4/O2 and SF6/O2 gas mixtures in the temperature range between 200 K and 1000 K. The data recommended are obtained from the isotropic (n-6) Lennard-Jones intermolecular interaction potentials of the pure substances by using the Hohm-Zarkova-Damyanova mixing rules. In general, a good agreement is observed between our results and the experimental and theoretical data found in the literature.

  9. HD gas analysis with Gas Chromatography and Quadrupole Mass Spectrometer

    CERN Document Server

    Ohta, T; Didelez, J -P; Fujiwara, M; Fukuda, K; Kohri, H; Kunimatsu, T; Morisaki, C; Ono, S; Rouille, G; Tanaka, M; Ueda, K; Uraki, M; Utsuro, M; Wang, S Y; Yosoi, M

    2011-01-01

    A gas analyzer system has been developed to analyze Hydrogen-Deuteride (HD) gas for producing frozen-spin polarized HD targets, which are used for hadron photoproduction experiments at SPring-8. Small amounts of ortho-H$_{2}$ and para-D$_{2}$ gas mixtures ($\\sim$0.01%) in the purified HD gas are a key to realize a frozen-spin polarized target. In order to obtain reliable concentrations of these gas mixtures in the HD gas, we produced a new gas analyzer system combining two independent measurements with the gas chromatography and the QMS. The para-H$_{2}$, ortho-H$_{2}$, HD, and D$_{2}$ are separated using the retention time of the gas chromatography and the mass/charge. It is found that the new gas analyzer system can measure small concentrations of $\\sim$0.01% for the otho-H$_2$ and D$_2$ with good S/N ratios.

  10. 鼓泡塔中水合物法分离混合气体的数值模拟%Numerical Simulation of Separating Gas Mixtures via Hydrate Formation in Bubble Column

    Institute of Scientific and Technical Information of China (English)

    罗艳托; 朱建华; 陈光进

    2007-01-01

    To develop a new technique for separating gas mixtures via hydrate formation, a set of medium-sized experimental bubble column reactor equipment was constructed.On the basis of the structure parameters of the experimental bubble column reactor, assuming that the liquid phase was in the axial dispersion regime and the gas phase was in the plug flow regime, in the presence of hydrate promoter tetrahydrofuran (THF), the rate of hydrogen enrichment for CH4+H2 gas mixtures at different operational conditions (such as temperature, pressure, concentration of gas components, gas flow rate, liquid flow rate) were simulated.The heat product of the hydrate reaction and its axial distribution under different operational conditions were also calculated.The results would be helpful not only to setting and optimizing operation conditions and design of multi-refrigeration equipment, but also to hydrate separation technique industrialization.

  11. Generation of 5,5-dimethyl-1-pyrroline N-oxide hydroxyl and scavenger radical adducts from copper/H2O2 mixtures: effects of metal ion chelation and the search for high-valent metal-oxygen intermediates.

    Science.gov (United States)

    Burkitt, M J; Tsang, S Y; Tam, S C; Bremner, I

    1995-10-20

    A metal-catalyzed nucleophilic addition mechanism for the formation of radical adducts of the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) has been described recently (K. Makino, T. Hagiwara, A. Hagi, M. Nishi, and A. Murakami, 1990, Biochem. Biophys. Res. Commun. 172, 1073-1080; P. M. Hanna, W. Chamulitrat, and R. P. Mason, 1992, Arch. Biochem. Biophys. 296, 640-644). In the present investigation, we have demonstrated that the recently reported inhibition of copper-dependent hydroxyl radical formation by the complexing agent 1,10-phenanthroline (OP), which appears to contradict the well-known chemical nuclease properties of CuI(OP)2, is an artifact resulting from an inhibition of the nucleophilic addition of water to DMPO by OP (A. C. Mello-Filho and R. Meneghini, 1991, Mutat. Res. 251, 109-113). Copper bound to OP was found to be a good catalyst of hydroxyl radical formation: the CuII(OP)2 complex can be reduced by H2O2 and the CuI(OP)2 generated reacts with the peroxide to form .OH. In contrast, no evidence could be obtained for oxidant formation from the CuII(aq)/H2O2 reaction system, despite the detection of a prominent signal from the DMPO hydroxyl radical adduct (DMPO/.OH) (the formation of which was due solely to the nucleophilic addition of water to DMPO). The failure to generate an oxidant in this reaction mixture was attributed to the failure of hydrogen peroxide to reduce CuII(aq), as hydroxyl radical formation did occur when CuI(aq) was added directly to H2O2. However, in order to account for the high concentration of alpha-hydroxyethanol radicals detected when ethanol was included in the CuI(aq)/H2O2 reaction, the possibility that an oxidant in addition to .OH (e.g., CuO+) is generated is discussed.

  12. Implementation of Ultrasonic Sensing for High Resolution Measurement of Binary Gas Mixture Fractions

    Directory of Open Access Journals (Sweden)

    Richard Bates

    2014-06-01

    Full Text Available We describe an ultrasonic instrument for continuous real-time analysis of the fractional mixture of a binary gas system. The instrument is particularly well suited to measurement of leaks of a high molecular weight gas into a system that is nominally composed of a single gas. Sensitivity < 5 × 10−5 is demonstrated to leaks of octaflouropropane (C3F8 coolant into nitrogen during a long duration (18 month continuous study. The sensitivity of the described measurement system is shown to depend on the difference in molecular masses of the two gases in the mixture. The impact of temperature and pressure variances on the accuracy of the measurement is analysed. Practical considerations for the implementation and deployment of long term, in situ ultrasonic leak detection systems are also described. Although development of the described systems was motivated by the requirements of an evaporative fluorocarbon cooling system, the instrument is applicable to the detection of leaks of many other gases and to processes requiring continuous knowledge of particular binary gas mixture fractions.

  13. Reduced-order modellin for high-pressure transient flow of hydrogen-natural gas mixture

    Science.gov (United States)

    Agaie, Baba G.; Khan, Ilyas; Alshomrani, Ali Saleh; Alqahtani, Aisha M.

    2017-05-01

    In this paper the transient flow of hydrogen compressed-natural gas (HCNG) mixture which is also referred to as hydrogen-natural gas mixture in a pipeline is numerically computed using the reduced-order modelling technique. The study on transient conditions is important because the pipeline flows are normally in the unsteady state due to the sudden opening and closure of control valves, but most of the existing studies only analyse the flow in the steady-state conditions. The mathematical model consists in a set of non-linear conservation forms of partial differential equations. The objective of this paper is to improve the accuracy in the prediction of the HCNG transient flow parameters using the Reduced-Order Modelling (ROM). The ROM technique has been successfully used in single-gas and aerodynamic flow problems, the gas mixture has not been done using the ROM. The study is based on the velocity change created by the operation of the valves upstream and downstream the pipeline. Results on the flow characteristics, namely the pressure, density, celerity and mass flux are based on variations of the mixing ratio and valve reaction and actuation time; the ROM computational time cost advantage are also presented.

  14. Carbon ion pump for removal of carbon dioxide from combustion gas and other gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D.; Bourcier, William L.

    2014-08-19

    A novel method and system of separating carbon dioxide from flue gas is introduced. Instead of relying on large temperature or pressure changes to remove carbon dioxide from a solvent used to absorb it from flue gas, the ion pump method, as disclosed herein, dramatically increases the concentration of dissolved carbonate ion in solution. This increases the overlying vapor pressure of carbon dioxide gas, permitting carbon dioxide to be removed from the downstream side of the ion pump as a pure gas. The ion pumping may be obtained from reverse osmosis, electrodialysis, thermal desalination methods, or an ion pump system having an oscillating flow in synchronization with an induced electric field.

  15. Carbon ion pump for removal of carbon dioxide from combustion gas and other gas mixtures

    Science.gov (United States)

    Aines, Roger D.; Bourcier, William L.

    2010-11-09

    A novel method and system of separating carbon dioxide from flue gas is introduced. Instead of relying on large temperature or pressure changes to remove carbon dioxide from a solvent used to absorb it from flue gas, the ion pump method, as disclosed herein, dramatically increases the concentration of dissolved carbonate ion in solution. This increases the overlying vapor pressure of carbon dioxide gas, permitting carbon dioxide to be removed from the downstream side of the ion pump as a pure gas. The ion pumping may be obtained from reverse osmosis, electrodialysis, thermal desalination methods, or an ion pump system having an oscillating flow in synchronization with an induced electric field.

  16. 高压下CO_2稀释的CO/H_2/Air火焰贫可燃极限处的辐射重吸收效应的数值研究%Numerical Investigation of Radiation Re-Absorption Influences on Flame Behaviors of CO/H_2/Air Mixtures With CO_2 Diluted Near Lean Flammability Limits at High Pressures

    Institute of Scientific and Technical Information of China (English)

    陶志强; 艾育华; 孔文俊

    2012-01-01

    One-dimensional laminar premixed flames for CO/H_2/air mixtures were investigated numerically for a wide range of pressures with different CO_2 diluted ratios.Re-absorption-included radiation model called statistical narrow-band correlated-k(SNBCK)model and re-absorption-excluded radiation model called optically thin(OPT)model were used respectively in order to assess the impacts of re-absorption on flame behaviors near lean flammability limits.Results revealed that re-absorption extended lean flammability limits and these effects increased with increasing CO2 addition or ratios of CO/H_2.Effect of re-absorption strengthened as pressures increased.The maximum flames temperature at lean flammability limits increased first and then decreased with a peak value at near 10atm as pressures increased.%本文分别采用考虑辐射重吸收的谱带辐射(SNBCK)模型及未考虑辐射重吸收的光学薄辐射(OPT)模型,对0.1~4 MPa,CO_2稀释比为0%和20%的一维预混层流合成气/空气火焰进行数值分析,研究辐射重吸收效应对可燃极限及极限处的火焰传播速度和温度的影响。结果表明,辐射重吸收效应能有效拓宽贫可燃极限,提高燃料中CO_2比例或提高CO/H_2比例都会加剧上述效果。辐射重吸收效应随压力增大而逐渐增强,并造成可燃极限处最大火焰温度随压力先增加后减小,在1 MPa左右达到峰值。

  17. Catalytic Combustion Characteristics of H2/n-CaH10/Air Mixtures in Swiss-Roll Combustor%H2/n-C4H10/Air预混气在Swiss—roll燃烧器中的催化燃烧特性

    Institute of Scientific and Technical Information of China (English)

    杨帆; 钟北京

    2012-01-01

    In micro catalytic combustion, due to the competitive adsorption between fuel and oxygen molecular on the catalyst surface, the lower combustion limits are at the fuel rich condition. To enhance the utilization of fuel and enlarge the flammable range, hydrogen was added into the n-butane/air mixtures. Then catalytic combustion characteristics of H2/n-C4H10/air mixtures in Swiss-roll combustor were studied. Experimental results indicate that the addition of hydrogen and enlarge the flammable range of n-butane and the lower limits is fuel lean. Thus the utilization of fuel is high. The steady state combustion experiments show that the highest temperature of combustor is at fuel rich.%在微尺度催化燃烧中,由于燃料和氧气对于催化剂表面活性位的竞争,导致了可燃下限为富燃的情况。为了提高燃料利用率,拓宽可燃范围,本文在正丁烷/空气的混合气中加入一定量的氢气,在Swiss—roll燃烧器内研究了氯气/正丁烷/空气预混气的燃烧特性。结果表明,氢气能够有效拓宽正丁烷的可燃范围,可燃下限能够低于1,以贫燃的条件实现高燃料利用率。对于稳定燃烧温度的实验结果表明,燃烧器最高温度出现在富燃料一侧。

  18. CFD Recombiner Modelling and Validation on the H2-Par and Kali-H2 Experiments

    Directory of Open Access Journals (Sweden)

    Stéphane Mimouni

    2011-01-01

    Full Text Available A large amount of Hydrogen gas is expected to be released within the dry containment of a pressurized water reactor (PWR, shortly after the hypothetical beginning of a severe accident leading to the melting of the core. According to local gas concentrations, the gaseous mixture of hydrogen, air and steam can reach the flammability limit, threatening the containment integrity. In order to prevent mechanical loads resulting from a possible conflagration of the gas mixture, French and German reactor containments are equipped with passive autocatalytic recombiners (PARs which preventively oxidize hydrogen for concentrations lower than that of the flammability limit. The objective of the paper is to present numerical assessments of the recombiner models implemented in CFD solvers NEPTUNE_CFD and Code_Saturne. Under the EDF/EPRI agreement, CEA has been committed to perform 42 tests of PARs. The experimental program named KALI-H2, consists checking the performance and behaviour of PAR. Unrealistic values for the gas temperature are calculated if the conjugate heat transfer and the wall steam condensation are not taken into account. The combined effects of these models give a good agreement between computational results and experimental data.

  19. Production de méthanol et d'alcools supérieurs à partir de gaz via (CO + H2 Production of Methanol and Higher Alcohols from Gas via (Co + H2

    Directory of Open Access Journals (Sweden)

    Kawata N.

    2006-11-01

    Full Text Available Dans le cadre des procédés en développement pour la synthèse d'alcools à partir de syngas (CO + H2, ce mémoire présente certains résultats récents de l'Institut Français du Pétrole (IFP (France et Idemitsu Kosan (Japon. La première démonstration du procédé, sous programme R et D du RAPAD-Japon, a confirmé les performances et la faisabilité. Les alcools sélectivement produits, après fractionnement, présentent de bonnes propriétés pour l'usage carburant. L'optimisation de l'ensemble constitué par la production du syngas, la synthèse, le fractionnement des alcools, a permis une simplification sensible du procédé, une optimisation spécifique des performances, ce qui conduit à des données économiques plus favorables. Within the framework of processes being developed for alcohol synthesis from syngas, this article describes some recent results obtained by Idemitsu-Kosan (Japan and Institut Français du Pétrole (IFP (France. The first demonstration of the process as part of the RAPAD-Japan R & D program has confirmed both its performances and feasibility. The alcohols selectively produced, after suitable fractionation, present good properties as a blend for motor fuels. The optimization of the overall process for syngas production, alcohol synthesis and alcohol fractionation has led to a significant simplification of the process and to the optimization of its performances, leading to better economics.

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

    Science.gov (United States)

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

    2010-04-13

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

  1. Discovery of Multiple, Ionization-Created Anions in Gas Mixtures Containing CS2 and O2

    CERN Document Server

    Snowden-Ifft, Daniel P

    2013-01-01

    The use of negative ions in TPCs has several advantages for high-resolution rare- event detection experiments. The DRIFT experiment, for example, has taken full advantage of this technique over the past decade in a directional search for dark matter. This paper focuses on the surprising discovery of multiple species of ionization-created CS2 anions, called minority carriers, in gas mixtures containing electronegative CS2 and O2, identified by their slightly different drift velocities. Measurements of minority carriers in gas mixtures of CS2, CF4 and O2 are reported in an effort to understand the nature of these charge carriers. Regardless of the micro-physics however, this discovery offers significant practical advantages for experiments such as DRIFT, where the difference in arrival time may be used to fiducialize the original ionization event without an external start pulse.

  2. Amplification and Scintillation Properties of Oxygen-Rich Gas Mixtures for Optical-TPC Applications

    CERN Document Server

    Weissman, L; Chechik, R; Dangendorf, V; Gai, M; Tittelmeier, K; Weller, H R

    2006-01-01

    We studied electron amplification and light emission from avalanches in oxygen-containing gas mixtures. The mixtures investigated in this work included, among others, CO2 and N2O mixed with Triethylamine (TEA) or N2. Double-Step Parallel Gap (DSPG) multipliers and THick Gas Electron Multipliers (THGEM) were investigated. High light yields were measured from CO2+N2 and CO2+TEA, though with different emission spectra. We observed the characteristic wave-length emission of N2 and of TEA and used a polymer wave-length shifter to convert TEA UV-light into the visible spectrum. The results of these measurements indicate the applicability of optical recording of ionizing tracks in a TPC target-detector designed to study the cross section of the 16O(g,a)12C reaction, a central problem in nuclear astrophysics.

  3. Eco-friendly gas mixtures for Resistive Plate Chambers based on Tetrafluoropropene and Helium

    CERN Document Server

    Abbrescia, M; Bianco, S; Ferrini, M; Muhammad, S; Passamonti, L; Pierluigi, D; Piccolo, D; Primavera, F; Russo, A; Saviano, G

    2016-01-01

    Due to the recent restrictions deriving from the application of the Kyoto protocol, the main components of the gas mixtures presently used in the Resistive Plate Chambers systems of the LHC experiments will be most probably phased out of production in the coming years. Identifying possible replacements with the adequate characteristics requires an intense R&D, which was recently started, also in collaborations across the various experiments. Possible candidates have been proposed and are thoroughly investigated. Some tests on one of the most promising candidate - HFO-1234ze, an allotropic form of tetrafluoropropane- have already been reported. Here an innovative approach, based on the use of Helium, to solve the problems related to the too elevate operating voltage of HFO-1234ze based gas mixtures, is discussed and the relative first results are shown.

  4. Eco-friendly gas mixtures for Resistive Plate Chambers based on tetrafluoropropene and Helium

    Science.gov (United States)

    Abbrescia, M.; Benussi, L.; Piccolo, D.; Bianco, S.; Ferrini, M.; Muhammad, S.; Passamonti, L.; Pierluigi, D.; Piccolo, D.; Primavera, F.; Russo, A.; Saviano, G.

    2016-08-01

    Due to the recent restrictions deriving from the application of the Kyoto protocol, the main components of the gas mixtures presently used in the Resistive Plate Chambers systems of the LHC experiments will be most probably phased out of production in the coming years. Identifying possible replacements with the adequate characteristics requires an intense R&D activity, which was recently started, in collaborations with various experiments. Possible new gases have been proposed and are thoroughly investigated. Some tests on one of the most promising candidate—HFO-1234ze, an allotropic form of tetrafluoropropane—have already been reported. Here an innovative approach, based on the use of Helium, to solve the problem related to the high operating voltage needed to operate the chambers with HFO-1234ze based gas mixtures, is discussed and the first results are shown.

  5. Theoretical and experimental analysis of a multiphase screw pump, handling gas-liquid mixtures with very high gas volume fractions

    Energy Technology Data Exchange (ETDEWEB)

    Raebiger, K. [LEISTRITZ Pumpen GmbH, Nuremberg (Germany); Faculty of Advanced Technology, University of Glamorgan, Pontypridd, Wales (United Kingdom); Maksoud, T.M.A.; Ward, J. [Faculty of Advanced Technology, University of Glamorgan, Pontypridd, Wales (United Kingdom); Hausmann, G. [Department of Mechanical Engineering and Building Services Engineering, University of Applied Sciences, Nuremberg (Germany)

    2008-09-15

    In the investigation of the pumping behaviour of multiphase screw pumps, handling gas-liquid mixtures with very high gas volume fractions, theoretical and experimental analyses were performed. A new theoretical screw pump model was developed, which calculates the time-dependent conditions inside the several chambers of a screw pump as well as the exchange of mass and energy between these chambers. By means of the performed experimental analysis, the screw pump model was verified, especially at very high gas volume fractions from 90% to 99%. The experiments, which were conducted with the reference fluids water and air, can be divided mainly into the determination of the steady state pumping behaviour on the one hand and into the analysis of selected transient operating conditions on the other hand, whereas the visualisation of the leakage flows through the circumferential gaps was rounded off the experimental analysis. (author)

  6. Electron attachment to oxygen, water, and methanol, in various drift chamber gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Huk, M.; Igo-Kemenes, P.; Wagner, A.

    1988-04-15

    Attachment of electrons to oxygen, water, and methanol molecules has been studied in various gas mixtures based on argon, methane and isobutane, a class of gases often used to operate large drift chambers. The measurements were performed using a drift chamber in which the conditions prevailing in large experiments could be closely reproduced. Attachment coefficients were extracted as a function of the gas composition and pressure, the drift field, and the concentration of the molecules under investigation. The observed effects are compared to other measurements, and are discussed within the frame of physical models. (orig.)

  7. Electron attachment to oxygen, water, and methanol, in various drift chamber gas mixtures

    Science.gov (United States)

    Huk, M.; Igo-Kemenes, P.; Wagner, A.

    1988-04-01

    Attachment of electrons to oxygen, water, and methanol molecules has been studied in various gas mixtures based on argon, methane and isobutane, a class of gases often used to operate large drift chambers. The measurements were performed using a drift chamber in which the conditions prevailing in large experiments could be closely reproduced. Attachment coefficients were extracted as a function of the gas composition and pressure, the drift field, and the concentration of the molecules under investigation. The observed effects are compared to other measurements, and are discussed within the frame of physical models.

  8. Phase diagrams for an ideal gas mixture of fermionic atoms and bosonic molecules

    DEFF Research Database (Denmark)

    Williams, J. E.; Nygaard, Nicolai; Clark, C. W.

    2004-01-01

    We calculate the phase diagrams for a harmonically trapped ideal gas mixture of fermionic atoms and bosonic molecules in chemical and thermal equilibrium, where the internal energy of the molecules can be adjusted relative to that of the atoms by use of a tunable Feshbach resonance. We plot...... diagrams obtained in recent experiments on the Bose-Einstein condensation to Bardeen-Cooper-Schrieffer crossover, in which the condensate fraction is plotted as a function of the initial temperature of the Fermi gas measured before a sweep of the magnetic field through the resonance region....

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

    Science.gov (United States)

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

    1987-01-01

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

  10. Mixture gas component concentration analysis based on support vector machine and infrared spectrum

    Institute of Scientific and Technical Information of China (English)

    Peng Bai; Junhua Liu

    2006-01-01

    @@ A novel quantitative analysis method of multi-component mixture gas concentration based on support vector machine (SVM) and spectroscopy is proposed. Through transformation of the kernel function, the seriously overlapped and nonlinear spectrum data are transformed in high-dimensional space, but the highdimensional data can be processed in the original space. Some factors, such as kernel function, range of the wavelength, and penalty coefficient, are discussed. This method is applied to the quantitative analysis of natural gas components concentration, and the component concentration maximal deviation is 2.28%.

  11. Formation of Singlet Fermion Pairs in the Dilute Gas of Boson-Fermion Mixture

    Directory of Open Access Journals (Sweden)

    Minasyan V.

    2010-10-01

    Full Text Available We argue the formation of a free neutron spinless pairs in a liquid helium -dilute neutron gas mixture. We show that the term, of the interaction between the excitations of the Bose gas and the density modes of the neutron, meditate an attractive interaction via the neutron modes, which in turn leads to a bound state on a spinless neutron pair. Due to presented theoretical approach, we prove that the electron pairs in superconductivity could be discovered by Frölich earlier then it was made by the Cooper.

  12. Formation of Singlet Fermion Pairs in the Dilute Gas of Boson-Fermion Mixture

    Directory of Open Access Journals (Sweden)

    Samoilov V.

    2010-10-01

    Full Text Available We argue the formation of a free neutron spinless pairs in a liquid helium -dilute neutron gas mixture. We show that the term, of the interaction between the excitations of the Bose gas and the density modes of the neutron, meditate an attractive interaction via the neutron modes, which in turn leads to a bound state on a spinless neutron pair. Due to presented theoretical approach, we prove that the electron pairs in superconductivity could be discovered by Froelich earlier then it was made by the Cooper.

  13. Continuous method to remove acid gases from a gas mixture supply

    Energy Technology Data Exchange (ETDEWEB)

    Butwell, K.F.; Kubek, D.J.

    1979-07-05

    It is proposed to remove acid gases - particularly CO/sub 2/ - from process gases (e.g. hydrocarbon mixtures, synthesis gas) by counter-current absorption with alcohol amines, to use monoethanol amine to which antimony and vanadium compounds are added as corrosion inhibitors. The patent claim includes a combination of 11 process steps, whose aim is to reduce the necessity of heating and cooling by external sources to a minimum. The method is described in detail.

  14. Non-porous metal membranes for selective separation of hydrogen from gas mixtures at higher temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Winkelmann, U.; Schulten, R.; Weirich, W.; Kuegler, B.; Luecke, L.; Oertel, M.; Pietsch, M.; Schmitz, J.

    1986-10-01

    Materials for selective separation of hydrogen from gas mixtures by means of a metal membrane must have high permeability for dissolved oxygen, catalytically active surfaces, and mechanical stability in a hydrogen atmosphere. The transition metals Nb, Ta, and V have high hydrogen permeability, but they must be coated with a catalytically active Pd alloy in order to permit hydrogen permeation. The alloy TiNi can be used without a noble metal coating.

  15. Viscous-shock-layer solutions for turbulent flow of radiating gas mixtures in chemical equilibrium

    Science.gov (United States)

    Anderson, E. C.; Moss, J. N.

    1975-01-01

    The viscous-shock-layer equations for hypersonic laminar and turbulent flows of radiating or nonradiating gas mixtures in chemical equilibrium are presented for two-dimensional and axially-symmetric flow fields. Solutions were obtained using an implicit finite-difference scheme and results are presented for hypersonic flow over spherically-blunted cone configurations at freestream conditions representative of entry into the atmosphere of Venus. These data are compared with solutions obtained using other methods of analysis.

  16. Viscous shock layer solutions for turbulent flow of radiating gas mixtures in chemical equilibrium

    Science.gov (United States)

    Anderson, E. C.; Moss, J. N.

    1975-01-01

    The viscous shock layer equations for hypersonic laminar and turbulent flows of radiating or nonradiating gas mixtures in chemical equilibrium are presented for two-dimensional and axially symmetric flow fields. Solutions are obtained using an implicit finite difference scheme and results are presented for hypersonic flow over spherically blunted cone configurations at free stream conditions representative of entry into the atmosphere of Venus. These data are compared with solutions obtained using other methods of analysis.

  17. Transport coefficients for relativistic gas mixtures of hard-sphere particles

    Science.gov (United States)

    Kremer, Gilberto M.; Moratto, Valdemar

    2017-04-01

    In the present work, we calculate the transport coefficients for a relativistic binary mixture of diluted gases of hard-sphere particles. The gas mixture under consideration is studied within the relativistic Boltzmann equation in the presence of a gravitational field described by the isotropic Schwarzschild metric. We obtain the linear constitutive equations for the thermodynamic fluxes. The driving forces for the fluxes of particles and heat will appear with terms proportional to the gradient of gravitational potential. We discuss the consequences of the gravitational dependence on the driving forces. We obtain general integral expressions for the transport coefficients and evaluate them by assuming a hard-sphere interaction amongst the particles when they collide and not very disparate masses and diameters of the particles of each species. The obtained results are expressed in terms of their temperature dependence through the relativistic parameter which gives the ratio of the rest energy of the particles and the thermal energy of the gas mixture. Plots are given to analyze the behavior of the transport coefficients with respect to the temperature when small variations in masses and diameters of the particles of the species are present. We also analyze for each coefficient the corresponding limits to a single gas so the non-relativistic and ultra-relativistic limiting cases are recovered as well. Furthermore, we show that the transport coefficients have a dependence on the gravitational field.

  18. 油气副产H_2S的脱除与应用%The Removing and Application of by-product H_2S from Petroleum and Natural Gas

    Institute of Scientific and Technical Information of China (English)

    周英; 刘宝生; 郎春燕; 陈小平

    2012-01-01

    Hydrogen sulfide is a mephitical gas,which exists widely in petroleum or natural gas exploration and mining,processing and post-treatment each link.It possesses strong corrosive and poisonous property.It threatens to the safety of human,causes the corrosion of the drilling equipment,and pollutes the drilling fluid,etc.But hydrogen sulfide can be used for deep processing to many valuable products.The paper introduces three industrial methods of the removal of hydrogen sulfide: Chemical method,Physical method,and Biological method.The hydrogen sulfide downstream products' development,application and the latest research progress are also described in the paper.China has a wealth of hydrogen sulfide resources,and vigorously developing its subsequent products has very broad prospects for development in future.%硫化氢是具有恶臭气味的气体,它广泛存在于油气勘探、开采、加工以及后处理等各个环节。它具有强烈的腐蚀性和剧毒性,危害人身安全、腐蚀油气设备和污染钻井液等。但是硫化氢可以深加工为许多极具价值的产品。文章介绍了脱除硫化氢的三种工业方法:化学法、物理法、生物法。论述了硫化氢下游产品的开发、应用及最新研究进展。我国具有丰富的硫化氢资源,大力开发硫化氢后续产品是今后发展的一个方向。

  19. Test beam studies of the TRD prototype filled with different gas mixtures based on Xe, Kr, and Ar

    Science.gov (United States)

    Celebi, E.; Brooks, T.; Joos, M.; Rembser, C.; Gurbuz, S.; Cetin, S. A.; Konovalov, S. P.; Tikhomirov, V. O.; Zhukov, K.; Fillipov, K. A.; Romaniouk, A.; Smirnov, S. Yu; Teterin, P. E.; Vorobev, K. A.; Boldyrev, A. S.; Maevsky, A.; Derendarz, D.

    2017-01-01

    Towards the end of LHC Run1, gas leaks were observed in some parts of the Transition Radiation Tracker (TRT) of ATLAS. Due to these leaks, primary Xenon based gas mixture was replaced with Argon based mixture in various parts. Test-beam studies with a dedicated Transition Radiation Detector (TRD) prototype were carried out in 2015 in order to understand transition radiation performance with mixtures based on Argon and Krypton. We present and discuss the results of these test-beam studies with different active gas compositions.

  20. Preparation and analysis of helium purge gas mixture to be used in Tritium Extraction System of LLCB TBM

    Science.gov (United States)

    Gayathri Devi, V.; Yadav, Deepak; Sircar, Amit

    2017-04-01

    Hydrogen isotopes are extracted from the Ceramic Breeder (CB) and liquid Lead Lithium (Pb-Li) breeder of Lead Lithium Ceramic Breeder (LLCB) Test Blanket Module (TBM) with Helium purge gas. 1000 ppm of hydrogen gas is mixed with the purge helium gas to facilitate improved extraction of hydrogen isotopes from the breeder zones by hydrogen swamping reactions [1]. An experimental set up is developed for making up the purge gas mixture with a composition similar to the purge gas composition to be used for extraction of hydrogen isotopes from CB and Pb-Li of LLCB TBM. This is achieved by introducing different ppm levels (1000 - 5000 ppm) of hydrogen in helium gas by flow control mechanism. The analysis of the purge gas mixture is performed using a highly sensitive Gas Chromatography (GC) system. This paper describes the detailed design of the experimental set-up and results for the analysis of different concentrations of hydrogen in helium purge gas.

  1. Ppb-level H2S detection for SF6 decomposition based on a fiber-amplified telecommunication diode laser and a background-gas-induced high-Q photoacoustic cell

    Science.gov (United States)

    Yin, Xukun; Dong, Lei; Wu, Hongpeng; Ma, Weiguang; Zhang, Lei; Yin, Wangbao; Xiao, Liantuan; Jia, Suotang; Tittel, Frank K.

    2017-07-01

    A ppb-level hydrogen sulfide (H2S) gas sensor for sulfur hexafluoride (SF6) decomposition analysis was developed by means of a background-gas-induced high-Q differential photoacoustic cell (PAC) and a fiber-amplified telecommunication diode laser. The watt-level excitation laser power compensates the sensitivity loss as a result of using a low cost, near-IR laser source. The differential design with a large cylindrical resonator diameter allows the PAC to accommodate the high power beam and maintain a low noise level output. The theory of background-gas-induced high-Q PAC is provided and was verified experimentally. A H2S detection limit (1σ) of 109 ppb in a SF6 buffer gas was achieved for an averaging time of 1 s, which corresponds to a normalized noise equivalent absorption coefficient of 2.9 × 10-9 cm-1 W Hz-1/2.

  2. 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 ...

  3. The Huber’s Method-based Gas Concentration Reconstruction in Multicomponent Gas Mixtures from Multispectral Laser Measurements under Noise Overshoot Conditions

    Directory of Open Access Journals (Sweden)

    V. A. Gorodnichev

    2016-01-01

    Full Text Available Laser gas analysers are the most promising for the rapid quantitative analysis of gaseous air pollution. A laser gas analysis problem is that there are instable results in reconstruction of gas mixture components concentration under real noise in the recorded laser signal. This necessitates using the special processing algorithms. When reconstructing the quantitative composition of multi-component gas mixtures from the multispectral laser measurements are efficiently used methods such as Tikhonov regularization, quasi-solution search, and finding of Bayesian estimators. These methods enable using the single measurement results to determine the quantitative composition of gas mixtures under measurement noise. In remote sensing the stationary gas formations or in laboratory analysis of the previously selected (when the gas mixture is stationary air samples the reconstruction procedures under measurement noise of gas concentrations in multicomponent mixtures can be much simpler. The paper considers a problem of multispectral laser analysis of stationary gas mixtures for which it is possible to conduct a series of measurements. With noise overshoots in the recorded laser signal (and, consequently, overshoots of gas concentrations determined by a single measurement must be used stable (robust estimation techniques for substantial reducing an impact of the overshoots on the estimate of required parameters. The paper proposes the Huber method to determine gas concentrations in multicomponent mixtures under signal overshoot. To estimate the value of Huber parameter and the efficiency of Huber's method to find the stable estimates of gas concentrations in multicomponent stationary mixtures from the laser measurements the mathematical modelling was conducted. Science & Education of the Bauman MSTU 108 The mathematical modelling results show that despite the considerable difference among the errors of the mixture gas components themselves a character of

  4. Research and Design of Thermophysical Gas-Liquid Mixture Parameters in Product Pipelines

    Science.gov (United States)

    Dudin, S. M.; Zemenkov, Yu D.; Maier, A. V.; Shabarov, A. B.

    2016-10-01

    Operational problems are hard to overcome because of the temperature and pressure conditions of the hydrocarbon flow in the pipe, as well as the composition of the hydrocarbon system and the geometry of the pipeline. It is known that energy costs to pump a unit mass of RH in the form of gas 2-3 times exceed energy costs to pump a unit mass of RH in the form of liquid. As far as energy conservation during RH transportation is concerned, an important task is development and application of a method to calculate the gas-liquid hydrocarbons flow, and heat and mass transfer in process and trunk pipelines during their design and operation. The authors have developed a calculation method which is used to analyze the hydrodynamic state and composition of the hydrocarbon mixture in each ith section of the pipeline when temperature-pressure and hydraulic conditions change. The developed technique was tested on the hydrocarbon mixture of de-ethanized condensate and oil transported from northern oil and gas condensate fields via the main gas condensate line to the refinery.

  5. Sub-Penning gas mixtures: new possibilities for ton- to kiloton-scale time projection chambers

    CERN Document Server

    Monreal, Benjamin; Luszczak, William

    2015-01-01

    In this work, we present the concept for large low-background experiments in which an unusual gas mixture gas serves as a seamless, high-QE, near-100\\%-coverage photodetector for scintillation or \\cerenkov photons. We fill a large time projection chamber with a VUV scintillating gas, plus an unusually small admixture dopant gas with a low ionization threshhold (and a high ionization yield), akin to a highly-underquenched Penning mixture. Scintillation photons travel far from a primary ionization site before converting into photoionization electrons. Using standard TPC methods, we can separately count both the primary ionization electrons (which occur along a dense track) and the scintillation-ionization electrons (which will occur over a large spherical region) without the use of PMTs. The scheme is compatible with very large detectors, in both two-phase and single-phase high pressure configurations. We discuss how the drift-axis position of an event can be reconstructed, and under what constraints we can exp...

  6. Analyze and solve the problem of excessive hydrogen sulfide content in CO2 emissions gas%CO2排放气中H2S超标的问题分析及解决

    Institute of Scientific and Technical Information of China (English)

    乔景红

    2013-01-01

    针对低温甲醇洗系统中排放气中H2S超标的问题,采用人、机、料、法、环的方法进行分析,并对分析出的主要原因制定相应的措施,使排放气的H2S含量达到设计值以内,解决了排放气中H2S超标的问题.%For the problem of excessive hydrogen sulfide as the emission gas in low temperature methanol washing system. This paper analyses the causes of this phenomena by human, machine, material, method and environment. Some advice about how to ensure that the concentration of hydrogen sulfide in the setting within were put forward. In this way, The problem of excessive hydrogen sulfide as the emission gas was solved.

  7. Estudo da degradação de ranitidina via H2O2 eletrogerado/Fenton em um reator eletroquímico com eletrodos de difusão gasosa Study of the ranitidine degradation by H2O2 electrogenerated/Fenton in a electrochemical reactor with gas diffusion electrode

    Directory of Open Access Journals (Sweden)

    André A. G. F. Beati

    2009-01-01

    Full Text Available The study of the electrochemical degradation of the ranitidine was developed using an electrochemical reactor with a gas diffusion electrode (GDE as cathode. The electrolysis experiments was performed at constant current (1 4 A. The process reached a production of 630 mg L-1 of the H2O2 at 7 A. The ranitidine concentrations was reduced in 99.9% (HPLC and chemical oxygen demand (COD was reduced in 86.7% by electro-Fenton.

  8. The H2O2-H2O Hypothesis: Extremophiles Adapted to Conditions on Mars?

    Science.gov (United States)

    Houtkooper, Joop M.; Schulze-Makuch, Dirk

    2007-08-01

    evolved into employing H2O2 as an antifreeze, which would also have the function as a water collector. If we would find life on Mars based on an intracellular H2O2-H2O mixture, this would not necessarily imply an independent origin of terrestrial and martian life. For that, a detailed study of the biochemistry and genetics is needed. The transfer of terrestrial organisms to Mars or vice versa is a possibility given favorable conditions for the origin and persistance of life on both planets early in solar system history (Schulze-Makuch and Houtkooper, 2007). The transfer of terrestrial organisms by early spacecrafts to Mars that either landed or crashed is a possibility, but it is not plausible that these organisms evolved in a few years. We suggest that we already have evidence of their existence from the Viking landers in two widely distant locations. The H2O2-H2O hypothesis does explain the Viking observations remarkably well, especially (1) the lack of organics detected by GC-MS, (2) the lack of detected oxidant(s) to support a chemical explanation, (3) evolution of O2 upon wetting (GEx experiment), (4) limited organic synthesis reactions (PR experiment), and (5) the gas release observations made (LR experiment)(Houtkooper and Schulze-Makuch, 2007). From the amounts of evolved CO2, O2 and N2 in the GEx experiment it can be concluded that the organisms have an excess oxidative content. This is a problem since in any destructive test, even by laser desorption-mass spectrometry (LDMS), the organisms may decompose completely into H2O, CO2, O2, and N2. The same will occur if the organisms are exposed to excess water, as they will perish due to hyperhydration. The consequence for future biology experiments is that the most fruitful approach may be the detection of metabolism under close to local environmental conditions, especially avoiding the addition of too much water. Of the Viking experiments, the PR experiment which aimed at carbon assimilation was the closest to

  9. SF sub 6 quenched gas mixtures for streamer mode operation of RPCs at very low voltages

    CERN Document Server

    Aielli, G; Cardarelli, R; Di Ciaccio, A; Di Stante, L; Liberti, B; Paoloni, A; Pastori, E; Santonico, R

    2002-01-01

    In the present paper we describe a search for gases that allow to reduce the energy of the electrical discharge produced in Resistive Plate Chambers (RPCs) operated in streamer mode, by reducing both the operating voltage and the released charge. This can be achieved, with current gas mixtures of argon, tetrafluoroethane (TFE) and isobutane, by reducing the total amount of quenching components (TFE+isobutane) down to 10-15% and compensating for the lower gas quenching power with the addition of small amounts of SF sub 6. We show here that SF sub 6 , even for concentrations as low as 1% or less, has a strong effect in reducing the delivered charge in low quenched gases and allows to achieve a proper working mode of the RPC even at voltages as low as 4-5 kV over a 2 mm gas gap.

  10. [Fire disaster due to deflagration of a propane gas-air mixture].

    Science.gov (United States)

    Nadjem, Hadi; Vogt, Susanne; Simon, Karl-Heinz; Pollak, Stefan; Geisenberger, Dorothee; Kramer, Lena; Pircher, Rebecca; Perdekampl, Markus Große; Thierauf-Emberger, Annette

    2015-01-01

    On 26 Nov 2012, a serious fire occurred at Neustadt/Black Forest in which 14 persons in a sheltered workshop died and 10 other individuals were injured. The fire was caused by the unbridled escape of propane gas due to accidental disconnection of the screw fixing between a gas bottle and a catalytic heater. Deflagration of the propane gas-air mixture set the workshop facilities on fire. In spite of partly extensive burns the fatally injured victims could be rapidly identified. The results of the fire investigations at the scene and the autopsy findings are presented. Carboxyhemoglobin concentrations ranged between 8 and 56 % and signs of fire fume inhalation were present in all cases. Three victims had eardrum ruptures due to the sudden increase in air pressure during the deflagration.

  11. Anomalous waves in gas-liquid mixtures near gas critical point in Gardner equation approximation

    Science.gov (United States)

    Gasenko, V. G.

    2016-10-01

    The waves in a bubbled incompressible liquid with Van der Waals gas in a bubbles being near critical points is considered in a frame of Gardner equation. It is shown that both coefficients on quadratic and cubic nonlinear terms in Gardner equation change the sign near gas critical point and it results the anomalous waves: negative and limited solitons, kinks, antikinks and breathers. The dynamics and interactions of these waves was studied numerically by high accuracy Fourier methods with periodically boundary conditions. In particular it is revealed that limited solitons always arise from initial distribution with a few identical soliton's pair and stand stable in their form after numerous interactions.

  12. Screening metal-organic frameworks by analysis of transient breakthrough of gas mixtures in a fixed bed adsorber

    NARCIS (Netherlands)

    Krishna, R.; Long, J.R.

    2011-01-01

    Metal-organic frameworks (MOFs) offer considerable potential for separating a variety of mixtures that are important in applications such as CO2 capture and H2 purification. In view of the vast number of MOFs that have been synthesized, there is a need for a reliable procedure for comparing

  13. Experimental study on size-dependency of effective permittivity of particle-gas mixture with agglomeration

    Institute of Scientific and Technical Information of China (English)

    Li Xiaomin; Xu Lijun; Li Songyun

    2007-01-01

    The effective medium approximation (EMA) theory is the basis of a capacitance sensor used for concentration measurement of a particulate solid flow, its measurement result is independent on particle size. In existence of particle agglomeration or aggradation, however, it is found that the effective permittivity of a gas/solid mixture is dependent on particle size. In this paper, a parallel plate, differential capacitance sensor is utilized to investigate the influence of particle size on the effective permittivity of the mixture in such a case. Static experiments using three materials including glass, limestone and quartz particles were carried out in an off-line manner. The volume fraction of particles being tested ranged from 20×10-6 to 600×10-6, while the particle size was between 3 and 100 μm. Experimental results show that the effective permittivity of a particle-gas mixture with particle agglomeration is larger than that predicted by EMA and the smaller the particle size, the larger the effective permittivity. The experiment process and analysis results are discussed in detail in the paper.

  14. Selective Sensing of Gas Mixture via a Temperature Modulation Approach: New Strategy for Potentiometric Gas Sensor Obtaining Satisfactory Discriminating Features

    Science.gov (United States)

    Li, Fu-an; Jin, Han; Wang, Jinxia; Zou, Jie; Jian, Jiawen

    2017-01-01

    A new strategy to discriminate four types of hazardous gases is proposed in this research. Through modulating the operating temperature and the processing response signal with a pattern recognition algorithm, a gas sensor consisting of a single sensing electrode, i.e., ZnO/In2O3 composite, is designed to differentiate NO2, NH3, C3H6, CO within the level of 50–400 ppm. Results indicate that with adding 15 wt.% ZnO to In2O3, the sensor fabricated at 900 °C shows optimal sensing characteristics in detecting all the studied gases. Moreover, with the aid of the principle component analysis (PCA) algorithm, the sensor operating in the temperature modulation mode demonstrates acceptable discrimination features. The satisfactory discrimination features disclose the future that it is possible to differentiate gas mixture efficiently through operating a single electrode sensor at temperature modulation mode. PMID:28287492

  15. Numerical Simulation and Analysis of Migration Law of Gas Mixture Using Carbon Dioxide as Cushion Gas in Underground Gas Storage Reservoir

    Institute of Scientific and Technical Information of China (English)

    ChuanKai Niu; YuFei Tan

    2014-01-01

    One of the major technical challenges in using carbon dioxide ( CO2 ) as part of the cushion gas of the underground gas storage reservoir ( UGSR) is the mixture of CO2 and natural gas. To decrease the mixing extent and manage the migration of the mixed zone, an understanding of the mechanism of CO2 and natural gas mixing and the diffusion of the mixed gas in aquifer is necessary. In this paper, a numerical model based on the three dimensional gas-water two-phase flow theory and gas diffusion theory is developed to understand this mechanism. This model is validated by the actual operational data in Dazhangtuo UGSR in Tianjin City, China. Using the validated model, the mixed characteristic of CO2 and natural gas and the migration mechanism of the mixed zone in an underground porous reservoir is further studied. Particularly, the impacts of the following factors on the migration mechanism are studied:the ratio of CO2 injection, the reservoir porosity and the initial operating pressure. Based on the results, the optimal CO2 injection ratio and an optimal control strategy to manage the migration of the mixed zone are obtained. These results provide technical guides for using CO2 as cushion gas for UGSR in real projects.

  16. Predicting the Dielectric Strength of c-C4F8 and SF6 Gas Mixtures by Monte Carlo Method

    Institute of Scientific and Technical Information of China (English)

    WU Bian-tao; XIAO Deng-ming

    2007-01-01

    An improved Monte Carlo method was used to simulate the motion of electrons in c-C4F8 and SF6 gas mixtures for pulsed townsend discharge. The electron swarm parameters such as effective ionization coefficient, (-α) and drift velocity over the E/N range from 280~700 Td(1Td= 10-21 V·m2) were calculated by employing a set of cross sections available in literature. From the variation cure of (-α) with SF6 partial pressure p, the limiting field (E/N)lim of gas mixture at different gas content was determined. It is found that the limiting field of c-C4F8 and SF6gas mixture is higher than that of pure SF6 at any SF6 mixture ratio. Simulation results show excellent agreement with experiment data available in previous literature.

  17. Removal of Carbon Dioxide from Gas Mixtures Using Ion-Exchanged Silicoaluminophosphates

    Science.gov (United States)

    Hernandez-Maldonado, Arturo J (Inventor); Rivera-Ramos, Milton E (Inventor); Arevalo-Hidalgo, Ana G (Inventor)

    2017-01-01

    Na+-SAPO-34 sorbents were ion-exchanged with several individual metal cations for CO2 absorption at different temperatures (273-348 K) and pressures (<1 atm). In general, the overall adsorption performance of the exchanged materials increased as follows: Ce3+H2, N2 and O2) due to strong ion-quadrupole interactions. Sr2+-SAPO-34 sorbents are by far the best option for CO2 removal from CH4 mixtures, especially at low concentrations.

  18. Analysis of Water Hammer with Different Closing Valve Laws on Transient Flow of Hydrogen-Natural Gas Mixture

    OpenAIRE

    Norazlina Subani; Norsarahaida Amin

    2015-01-01

    Water hammer on transient flow of hydrogen-natural gas mixture in a horizontal pipeline is analysed to determine the relationship between pressure waves and different modes of closing and opening of valves. Four types of laws applicable to closing valve, namely, instantaneous, linear, concave, and convex laws, are considered. These closure laws describe the speed variation of the hydrogen-natural gas mixture as the valve is closing. The numerical solution is obtained using the reduced order m...

  19. Study on a pulse tube cryocooler using gas mixture as its working fluid

    Science.gov (United States)

    Gao, C. M.; He, Y. L.; Chen, Z. Q.

    2000-01-01

    In order to improve the performance of a one-stage pulse tube cryocooler, gas mixtures are used for comparison, which have been used in other cryocoolers. A mixture of hydrogen and helium was investigated in this study. When the structure of the pulse tube is the same as mentioned in [C. Wang, P.Y. Wu, Zh.Q. Chen, Numerical modeling of an orifice pulse tube cryocooler, Cryogenics 32 (1992) 785] and the working conditions are: frequency 15 Hz, average pressure 1.1 MPa, hot end temperature 300 K and cold end temperature 80 K, it has been found that there are optimal molar percentage for the maximal cooling power and the maximal-coefficient of performance (COP) of this cryocooler.

  20. Measurements of ion mobility in argon and neon based gas mixtures

    Science.gov (United States)

    Deisting, Alexander; Garabatos, Chilo; Szabo, Alexander; Vranic, Danilo

    2017-02-01

    As gaseous detectors are operated at high rates of primary ionisation, ions created in the detector have a considerable impact on the performance of the detector. The upgraded ALICE Time Projection Chamber (TPC) will operate during LHC Run 3 with a substantial space charge density of positive ions in the drift volume. In order to properly simulate such space charges, knowledge of the ion mobility K is necessary. To this end, a small gaseous detector was constructed and the ion mobility of various gas mixtures was measured. To validate the corresponding signal analysis, simulations were performed. Results are shown for several argon and neon based mixtures with different CO2 fractions. A decrease of K was measured for increasing water content.

  1. Discrete velocity computations with stochastic variance reduction of the Boltzmann equation for gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, Peter; Varghese, Philip; Goldstein, David [ASE-EM Department, UT Austin, 210 East 24th St, C0600, Austin, TX 78712 (United States)

    2014-12-09

    We extend a variance reduced discrete velocity method developed at UT Austin [1, 2] to gas mixtures with large mass ratios and flows with trace species. The mixture is stored as a collection of independent velocity distribution functions, each with a unique grid in velocity space. Different collision types (A-A, A-B, B-B, etc.) are treated independently, and the variance reduction scheme is formulated with different equilibrium functions for each separate collision type. The individual treatment of species enables increased focus on species important to the physics of the flow, even if the important species are present in trace amounts. The method is verified through comparisons to Direct Simulation Monte Carlo computations and the computational workload per time step is investigated for the variance reduced method.

  2. Measurements of ion mobility in argon and neon based gas mixtures

    CERN Document Server

    Deisting, Alexander; Szabo, Alexander; Vranic, Danilo

    2016-01-01

    As gaseous detectors are operated at high rates of primary ionisation, ions created in the detector have a considerable impact on the performance of the detector. The upgraded ALICE Time Projection Chamber (TPC) will operate during LHC Run$\\,3$ with a substantial space charge density of positive ions in the drift volume. In order to properly simulate such space charges, knowledge of the ion mobility $K$ is necessary. To this end, a small gaseous detector was constructed and the ion mobility of various gas mixtures was measured. To validate the corresponding signal analysis, simulations were performed. Results are shown for several argon and neon based mixtures with different $\\textrm{CO}_2$ fractions. A decrease of $K$ was measured for increasing water content.

  3. Modeling phase equilibria for acid gas mixtures using the CPA equation of state. Part IV. Applications to mixtures of CO2 with alkanes

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Ali, Shahid; Kontogeorgis, Georgios

    2015-01-01

    The thermodynamic properties of pure gaseous, liquid or supercritical CO2 and CO2 mixtures with hydrocarbons and other compounds such as water, alcohols, and glycols are very important in many processes in the oil and gas industry. Design of such processes requires use of accurate thermodynamic...

  4. Metallurgical response of an AISI 4140 steel to different plasma nitriding gas mixtures

    Directory of Open Access Journals (Sweden)

    Adão Felipe Oliveira Skonieski

    2013-01-01

    Full Text Available Plasma nitriding is a surface modification process that uses glow discharge to diffuse nitrogen atoms into the metallic matrix of different materials. Among the many possible parameters of the process, the gas mixture composition plays an important role, as it impacts directly the formed layer's microstructure. In this work an AISI 4140 steel was plasma nitrided under five different gas compositions. The plasma nitriding samples were characterized using optical and scanning electron microscopy, microhardness test, X-ray diffraction and GDOES. The results showed that there are significant microstructural and morphological differences on the formed layers depending on the quantity of nitrogen and methane added to the plasma nitriding atmosphere. Thicknesses of 10, 5 and 2.5 µm were obtained when the nitrogen content of the gas mixtures were varied. The possibility to obtain a compound layer formed mainly by γ'-Fe4N nitrides was also shown. For all studied plasma nitriding conditions, the presence of a compound layer was recognized as being the responsible to hinder the decarburization on the steel surface. The highest value of surface hardness - 1277HV - were measured in the sample which were nitrided with 3vol.% of CH4.

  5. Implementation of Ultrasonic Sensing for High Resolution Measurement of Binary Gas Mixture Fractions

    CERN Document Server

    Bates, Richard; Berry, Stephane; Bitadze, Alexander; Bonneau, Pierre; Bousson, Nicolas; Boyd, George; Bozza, Gennaro; Crespo-Lopez, Olivier; Da Riva, Enrico; Degeorge, Cyril; Deterre, Cecile; DiGirolamo, Beniamino; Doubek, Martin; Favre, Gilles; Godlewski, Jan; Hallewell, Gregory; Hasib, Ahmed; Katunin, Sergey; Langevin, Nicolas; Lombard, Didier; Mathieu, Michel; McMahon, Stephen; Nagai, Koichi; Pearson, Benjamin; Robinson, David; Rossi, Cecilia; Rozanov, Alexandre; Strauss, Michael; Vitek, Michal; Vacek, Vaclav; Zwalinski, Lukasz

    2014-01-01

    We describe an ultrasonic instrument for continuous real-time analysis of the fractional mixture of a binary gas system. The instrument is particularly well suited to measurement of leaks of a high molecular weight gas into a system that is nominally composed of a single gas. Sensitivity < 5 ×10−5 is demonstrated to leaks of octaflouropropane (C3F8) coolant into nitrogen during a long duration (18 month) continuous study. The sensitivity of the described measurement system is shown to depend on the difference in molecular masses of the two gases in the mixture. The impact of temperature and pressure variances on the accuracy of the measurement is analysed. Practical considerations for the implementation and deployment of long term, in situ ultrasonic leak detection systems are also described. Although development of the described systems was motivated by the requirements of an evaporative fluorocarbon cooling system, the instrument is applicable to the detection of leaks of many other gases and to proce...

  6. Life cycle greenhouse emissions of compressed natural gas-hydrogen mixtures for transportation in Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, P. [Instituto de Energia y Desarrollo Sustentable, CNEA, CONICET, Av. del Libertador 8250, Ciudad Autonoma de Buenos Aires (Argentina); Dawidowski, L.; Gomez, D. [Gerencia Quimica, CNEA, Av. Gral. Paz 1499, San Martin (Argentina); Pasquevich, D. [Instituto de Energia y Desarrollo Sustentable, CNEA, CONICET, Av. del Libertador 8250, Ciudad Autonoma de Buenos Aires (Argentina); Centro Atomico Bariloche, CNEA, Av. Bustillo 9500, S.C. de Bariloche (Argentina)

    2010-06-15

    We have developed a model to assess the life cycle greenhouse emissions of compressed natural gas-hydrogen (CNG-H{sub 2}) mixtures used for transportation in Argentina. The overall fuel life cycle is assessed through a well-to-wheel (WTW) analysis for different hydrogen generation and distribution options. The combustion stage in road vehicles is modeled using the COPERT IV model. Hydrogen generation options include classical steam methane reforming (SMR) and water electrolysis (WE) in central plants and distributed facilities at the refueling stations. Centralized hydrogen generation by electrolysis in nuclear plants as well as the use of solar photovoltaic and wind electricity is also considered. Hydrogen distribution options include gas pipeline and refrigerated truck transportation for liquefied hydrogen. A total number of fifteen fuel pathways are studied; in all the cases the natural gas-hydrogen mixture is made at the refueling station. The use of WE using nuclear or wind electricity appears to be less contaminant that the use of pure CNG. (author)

  7. H-2 incompatible chimera

    Energy Technology Data Exchange (ETDEWEB)

    Matzinger, P.; Mirkwood, G.

    1978-07-01

    Fully H-2 incompatible radiation chimeras were prepared using BALB congenic mice. Such chimeric mice were immunized in vivo against histocompatibility antigens of the C57BL/10Sn (B10) background in association with either the parental H-2 haplotypes, and their spleen cells subsequently boosted in vitro with the same minor antigens. Strong H-2-restricted cytotoxic activity against minor antigens was detected, and the specificity of the restriction could be to the H-2 haplotype of the donor or the host depending on the cells used for priming or boosting. Cross priming could also be demonstrated in these mice. The results show that fully allogenic radiation chimeras can produce H-2-restricted T-cell responses to minor histocompatibility (H) antigens, and are discussed in relation to contrasting results.

  8. Highly selective quantum sieving of D2 from H2 by a metal-organic framework as determined by gas manometry and infrared spectroscopy.

    Science.gov (United States)

    FitzGerald, Stephen A; Pierce, Christopher J; Rowsell, Jesse L C; Bloch, Eric D; Mason, Jarad A

    2013-06-26

    The quantum sieving effect between D2 and H2 is examined for a series of metal-organic frameworks (MOFs) over the temperature range 77-150 K. Isothermal adsorption measurements demonstrate a consistently larger isosteric heat of adsorption for D2 vs H2, with the largest difference being 1.4 kJ/mol in the case of Ni-MOF-74. This leads to a low-pressure selectivity for this material that increases from 1.5 at 150 K to 5.0 at 77 K. Idealized adsorption solution theory indicates that the selectivity decreases with increasing pressure, but remains well above unity at ambient pressure. Infrared measurements on different MOF materials show a strong correlation between selectivity and the frequency of the adsorbed H2 translational band. This confirms that the separation is predominantly due to the difference in the zero-point energies of the adsorbed isotopologues.

  9. An investigation of condensation from steam-gas mixtures flowing downward inside a vertical tube

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, S.Z.; Schrock, V.E.; Peterson, P.F. [Univ. of California, Berkeley, CA (United States)

    1995-09-01

    Previous experiments have been carried out by Vierow, Ogg, Kageyama and Siddique for condensation from steam/gas mixtures in vertical tubes. In each case the data scatter relative to the correlation was large and there was not close agreement among the three investigations. A new apparatus has been designed and built using the lessons learned from the earlier studies. Using the new apparatus, an extensive new data base has been obtained for pure steam, steam-air mixtures and steam-helium mixtures. Three different correlations, one implementing the degradation method initially proposed by Vierow and Schrock, a second diffusion layer theory initially proposed by Peterson, and third mass transfer conductance model are presented in this paper. The correlation using the simple degradation factor method has been shown, with some modification, to give satisfactory engineering accuracy when applied to the new data. However, this method is based on very simplified arguments that do not fully represent the complex physical phenomena involved. Better representation of the data has been found possible using modifications of the more complex and phenomenologically based method which treats the heat transfer conductance of the liquid film in series with the conductance on the vapor-gas side with the latter comprised of mass transfer and sensible heat transfer conductance acting in parallel. The mechanistic models, based on the modified diffusion layer theory or classical mass transfer theory for mass transfer conductance with transpiration successfully correlate the data for the heat transfer of vapor-gas side. Combined with the heat transfer of liquid film model proposed by Blangetti, the overall heat transfer coefficients predicted by the correlations from mechanistic models are in close agreement with experimental values.

  10. Role of thermal diffusion in cw IR laser absorption in gas mixtures.

    Science.gov (United States)

    Maleissye, J T; Lempereur, F

    1982-01-15

    The absorption of radiation from a cw CO(2) laser by a mixture of absorbing SF(6) and transparent buffer gases has been measured as a function of pressure of added transparent gas (C(4)H(10)). The results are analyzed in terms of thermal diffusion of excited SF6 molecules out of the irradiation zone. In the 60-400-Torr pressure range, thermal difusion depletes the concentration of SF(6) so that the overall absorption is decreased and competes with the various channels of collisional relaxation which enhance absorption. An approximate semiempirical expression is used to determine the transient perturbation of concentration which occurs inside the laser beam.

  11. New amines for the reversible absorption of carbon dioxide from gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Michele Aresta; Angela Dibenedetto [University of Bari, Bari (Italy). Department of Chemistry and METEA Research Center

    2003-07-01

    This paper discusses the use of new amines as a medium for the capture of CO{sub 2} from a gas mixture. The study was carried out comparing the absorption of carbon dioxide by two alkyl-di-amines with that of amines used so far at industrial level, namely mono-ethanolamine (MEA). A known mono silyl-alkyl-amine was also studied for comparison. The absorption of carbon dioxide was studied at different temperatures, in water solution, in organic solvents and using the neat amine. Several cycles of absorption/desorption were carried out. Xerogel solidified amines were also used. 12 refs., 6 figs.

  12. 离子液体[BMIM]Cl-水体系中纤维素制氢试验研究%Experimental study of hydrogen production from cellulose in ionic liquid [BMIM]Cl-H2O mixtures

    Institute of Scientific and Technical Information of China (English)

    孙孟林; 胡国新; 赵宇; 邹鑫

    2013-01-01

    以纳米二氧化钛为原料,在130℃水热合成钛酸纳米管TNTs后,用1 mol/L硫酸浸渍,450℃焙烧制备了SO42-/TNTs固体酸催化剂,并用XRD,SEM对纳米TiO2,TNTs,SO42-/TNTs进行表征.将制备的SO42-/TNTs与氧化锌混合用于离子液体[BMIM]Cl-水体系中微晶纤维素制氢反应,考察了催化剂、离子液体水含量及反应温度等因素对氢气产量的影响.试验表明,与微孔分子筛HZSM-5相比,SO42-/INTs更有利于纤维素制氢反应,在相同的催化剂用量下,后者的氢气产量比前者提高了约60%.试验还发现,同一催化剂在使用量不同时,所得氢气产量有很大差异,催化剂由50 mg增至150 mg后,氢气产量提高了近两倍,达到132.33 μmol/(g·h).离子液体加水量的多少对氢气产量也有很大影响,加水后氢气产量增多,但若加水过多氢气产量反而有所下降.%Take nano-TiO2 as raw materials,hydrothermal synthesized TNTs at 130 ℃ then in lmol/L H2SO4 impregnation and 450 ℃ calcinations to prepare solid acid catalyst of SO42-/TNTs,meanwhile,Nano-TiO2,TNTs and SO42-/TNTs was characterized using XRD and SEM.and the prepared SO42-/TNTs and ZnO was mixed in the [BMIM]Cl-H2O mixtures for hydrogen production reaction from microcrystalline cellulose,and the influence of catalyst,ionic liquid-H2O ratio,and temperature on the yield of hydrogen was investigated.The results show that SO42-/TNTs is more favorable to hydrogen production than molecular sieve HZSM-5,and the yield of hydrogen is increased by 60% under the same catalyst dosage.The results also show that the amount of the catalyst can make a big difference to the yield of hydrogen.When the amount of catalyst was increased from 50 mg to 150 mg,the yield of hydrogen almost tripled to 132.33 μmol/(g·h).Besides,the ratio of [BMIM]Cl and water has a big influence on the yield of hydrogen,hydrogen production increased when adding water,though decreased when the amount of water is too much.

  13. Formation of Nanodroplets in N2/H2O/SO2 under Irradiation of Fast Proton Beams

    DEFF Research Database (Denmark)

    Nakai, Youchi; Shigeoka, Tomita; Funada, Shuhei

    of the droplet growth in thebinary nucleation process of water and H2SO4.We have performed irradiation of proton beam on the gas mixture of N2/H2O/SO2 andAir/H2O/SO2. The reduction of SO2 concentration by beam irradiation was monitored usingan SO2 meter and the size distributions of generated droplets were...... measured with adifferential mobility analyzer. We found that the mass yield of generated droplets showedlinear dependence on the amount of SO2 oxidation. This behavior is different from binarynucleation theory of water and H2SO4. The difference might indicates importance ofconsidering the droplet formation...

  14. Regeneration of Pt-catalysts deactivated in municipal waste flue gas with H2/N2 and the effect of regeneration step on the SCR catalyst

    DEFF Research Database (Denmark)

    Due-Hansen, Johannes; Rasmussen, Søren Brik; Kustov, Arkady;

    on reduction with hydrogen. This procedure had negligible effect on the performance of the SCR catalyst. After treatment with 2% H2, 8% O2 in N2 for one hour, a slight better NO SCR activity was observed due to increase in the concentration V4+ sites. However, after exposure in normal NO SCR gases the activity...

  15. The Structures and Dehydrogenation Properties of MgH2-Al2O3 Ball-milled Hydrogen Storage Mixture%MgH2-Al2O3球磨储氢复合体系的组织结构及解氢性能

    Institute of Scientific and Technical Information of China (English)

    朱璞; 张健; 郭书振; 王旭

    2013-01-01

    采用机械球磨技术制备了MgH2-10%Al2O3(质量分数)储氢复合体系,通过XRD、SEM、DSC-TG等检测手段考查了微量Al2O3陶瓷颗粒掺杂对MgH2体系组织结构及解氢性能的影响,并对其相关机理进行了分析.结果表明:机械球磨可有效细化MgH2颗粒;在微量Al2O3陶瓷颗粒与机械球磨的协同作用下,MgH2颗粒的细化效果更为显著;相对于纯MgH2球磨体系而言,微量Al2O3的掺杂有效降低了MgH2体系的解氢温度(降低近50℃),且其解氢速率也有所提高;MgH2-Al2O3储氢复合体系解氢性能的改善主要源于Al2O3陶瓷颗粒对MgH2体系的组织细化效应.

  16. 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.

  17. Gas suspension flows of a moderately dense binary mixture of solid particles in vertical tubes

    Energy Technology Data Exchange (ETDEWEB)

    Zamankhan, P.; Huotari, J. [VTT Energy, Jyvaeskylae (Finland). Combustion and Conversion Lab.

    1996-12-01

    The turbulent, steady, fully-developed flow of a moderately dense (solid volume faction >>0.001) binary mixture of spherical particles in a gaseous carrier is investigated for the case of flow in a vertical riser. The suspended particles are considered to be in turbulent motion, driven by random aerodynamic forces acting between the particle and the gaseous carrier as well as particle-particle interactive forces. A model is constructed based on the combination of the time-averaged after volume-averaged conservation equations of mass, momentum and mechanical energy of the gas phase in the continuum theory and the corresponding equations for the solid particles obtained using the recently developed Enskog theory for dense multi-component mixtures of slightly inelastic spherical particles. The model properly takes into account the contributions of particle-particle collisions, as well as the fluid-dynamic fluctuating forces on individual particles. To demonstrate the validity of this approach, the fully-developed steady-state mean velocity and concentration distributions of a moderately dense binary mixture of solid particles in a turbulent vertical flow calculated by the present model are compared with available experimental measurements. The results provide a qualitative description of the experimentally observed motion of coarse particles in a fast bed of fine solids. (author)

  18. 泥炭生物过滤器脱除复合恶臭气中的 H2S%DEODORIZATION OF HYDROGEN SULFIDE IN COMPLEX MALODOROUS GAS BY PEAT BIO-FILTER

    Institute of Scientific and Technical Information of China (English)

    王玉亭; 郭兵兵; 曾向东

    2001-01-01

    Deodorization of hydrogen sulfide in laboratory prepared complex malodorous gas containing hydrogen sulfide, dimethyl-disulfide and toluene by peat bio-filter, and the presence of dimethyl-disulfide and toluene in the gas on the effect of hydrogen sulfide removal were studied respectively. The results showed that the hydrogen sulfide removal rate was about 100% and could be kept for a long time at an inlet load of hydrogen sulfide less than 45g/m3*h. The effect of reaction temperature on hydrogen sulfide removal was significant, the appropriate temperature was higher than 20 ℃. The malodorous gas containing dimethyl-disulfide and toluene showed little effect on hydrogen sulfide removal. The said deodorization method is proposed to purify the malodorous gas from wastewater treatment.%在实验室以配制的含 H2S 复合恶臭气为对象,研究 H2S 的生物脱除工艺及二甲基二硫化物、甲苯的存在对 H2S 脱除的影响。结果表明, H2S 入口负荷在45 g/(m3*h)以下时,H2S 脱除率可接近100%,并保持长时间的恒定,负荷波动幅度可达到30.3 g/(m3*h)。反应温度对 H2S 脱除有较大影响,适宜的反应温度为20 ℃以上;甲苯、二甲基二硫化物的存在对 H2S 的生物脱除基本没有影响。该工艺可用于净化污水处理场排放的恶臭气体。

  19. One-Parameter Equation of State for Gases and Gas Mixtures

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@1 INTRODUCTION There are many equations of state that can be appliedto calculate pVT and thermodynamic properties forfluids. The simplest equation of state for gas is thefamous virial equations with the second coefficient B Z = 1 + B/V (1-1) = 1 + Bp/(RT) (1-2)The accuracy of the third virial equations Z = 1 + B/V + C/V2 (1-3)Z = 1 + Bp/(RT) + C′p2 (1-4)is much higher than that of the second virial equa-tions especially in dense region, but the third virial coefficient C and C′ can not be obtained conveniently in literature especially for mixtures. In this paper, a simple equation of state using the second virial coeffi-cient only, Z = exp(1.1B/V), was proposed for gases and gas mixtures. When the reduced temperature is lower than 1.04, the accuracy of