共查询到20条相似文献,搜索用时 31 毫秒
1.
Shin-Kun Ryi Jong-Soo Park Kyung-Ran HwangChun-Boo Lee Sung-Wook Lee 《International Journal of Hydrogen Energy》2013
This study investigates the module configuration for upscaling CO2 capture capacity to a bench-scale in hydrogen selective Pd-based composite membranes. In order to confirm effective upscaling, four plate-type membranes of two inch diameter were stacked in a newly designed plate-and-frame type module, reaching a total membrane surface area of 6.64 × 10−3 m2 (66.4 cm2). A pure gas test carried out using H2 and He confirmed that there were no effects of module configuration in gas permeation behavior, indicating that the upscale of the separation capacity by numbering-up of membranes using our module design was successful. The CO2 enrichment test was conducted using a 40%CO2 + 60%H2 mixture (i.e. a similar composition for the coal gasifier after both the shift reaction and H2O removal), under high feed pressure and flow rate, i.e. 600–2100 kPa and 0.48–0.72 N m3 h−1. The mixture gas test confirmed that the bench-scale membrane module could enrich 40% of the CO2 at a feed flow rate of 0.48 N m3 h−1 up to 93% with a hydrogen recovery ratio of >90% at 673 K and a total feed pressure of 2100 kPa, i.e. ∼4 times CO2 enrichment capacity of one membrane. 相似文献
2.
Jonathan Mbah Burton Krakow Elias Stefanakos John T. Wolan 《International Journal of Hydrogen Energy》2009
The gas permeability of H2S gas at 150 °C through ultra-thin cesium hydrogen sulfate (CsHSO4) membranes has been investigated. Gas chromatography–mass spectrometry analyses indicate that CsHSO4 membrane is impermeable to H2S gas under test conditions. The apparent micropore diameter of the membrane averaged between 9.5 and 11.5 Å with a maximum permeance of 0.09 Barrer (6.75 × 10−19 m2 s−1 Pa−1). Atomic force microscope and X-ray diffraction analyses show respectively that the surface morphology and crystal structure of the membranes are preserved, with no adverse effect from prolonged exposure to H2S gas. Electrochemical impedance spectroscopy analysis confirm over a 30% decrease in membrane resistance via an 80% reduction in membrane thickness. 相似文献
3.
José Antonio Calles Raúl SanzDavid Alique Laura Furones 《International Journal of Hydrogen Energy》2014
This work comprises a study of hydrogen separation with a composite Pd-YSZ-PSS membrane from mixtures of H2, N2, CO and CO2, typical of a water gas shift reactor. The Pd layer is extended over a tubular porous stainless steel support (PSS) with an intermediate layer of yttria-stabilized-zirconia (YSZ). YSZ and Pd layers were incorporated over the PSS using Atmospheric Plasma Spraying and Electroless Plating techniques, respectively. The Pd and YSZ thickness values are 13.8 and 100 μm, respectively, and the Pd layer is fully dense. Permeation measurements with pure, binary and ternary gases at different temperatures (350–450 °C), trans-membrane pressures (0–2.5 bar) and gas composition have been carried out. Moreover, thermal stability of the membrane was also checked by repeating permeation measurements after several cycles of heating and cooling the system. Membrane hydrogen permeances were calculated using Sieverts' law, obtaining values in the range of 4·10−5–4·10−4 mol m−2 s−1 Pa−0.5. The activation energy of the permeance was also calculated using Arrhenius' equation, obtaining a value of 16.4 kJ/mol. In spite of hydrogen selectivity being 100% for all experiments, the hydrogen permeability was affected by the composition of feed gas. Thus, a significant depletion in H2 permeate flux was observed when other gases were in the mixture, especially CO, being also more or less significant depending on gas composition. 相似文献
4.
Zhou Hong Feng SunDongdong Chen Chun ZhangXuehong Gu Nanping Xu 《International Journal of Hydrogen Energy》2013
MFI zeolite membranes were synthesized on porous α-alumina hollow fibers by in-situ hydrothermal synthesis. The membranes were further modified for H2 separation by on-stream catalytic cracking deposition of methyldiethoxysilane (MDES) in the zeolitic pores. The separation performance of the modified membranes was characterized by separation of H2/CO2 gas mixture at 500 °C. Activation of MFI zeolite membranes by air at 500 °C was found to promote catalytic cracking deposition of silane in the zeolitic pores effectively, which resulted in significant improvement of H2-separating performance. The H2/CO2 separation factor of 45.6 with H2 permeance of 1.0 × 10−8 mol m−2 s−1 Pa−1 was obtained at 500 °C for a modified hollow fiber MFI zeolite membrane. The as-made membranes showed good thermochemical stability for the separation of H2/CO2 gas mixture containing H2O and H2S, respectively. 相似文献
5.
This study investigated the effect of gases such as CO2, N2, H2O on hydrogen permeation through a Pd-based membrane −0.012 m2 – in a bench-scale reactor. Different mixtures were chosen of H2/CO2, H2/N2/CO2 and H2/H2O/CO2 at temperatures of 593–723 K and a hydrogen partial pressure of 150 kPa. Operating conditions were determined to minimize H2 loss due to the reverse water gas shift (RWGS) reaction. It was found that the feed flow rate had an important effect on hydrogen recovery (HR). Furthermore, an identification of the inhibition factors to permeability was determined. Additionally, under the selected conditions, the maximum hydrogen permeation was determined in pure H2 and the H2/CO2 mixtures. The best operating conditions to separate hydrogen from the mixtures were identified. 相似文献
6.
The search for a clean energy source as well as the reduction of CO2 emissions to the atmosphere are important strategies to resolve the current energy shortage and global warming issues. We have demonstrated, for the first time, a Pebax/poly(dimethylsiloxane)/polyacrylonitrile (Pebax/PDMS/PAN) composite hollow fiber membrane not only can be used for flue gas treatment but also for hydrogen purification. The composite membranes display attractive gas separation performance with a CO2 permeance of 481.5 GPU, CO2/H2 and CO2/N2 selectivity of 8.1 and 42.0, respectively. Minimizing the solution intrusion using the PDMS gutter layer is the key to achieving the high gas permeance while the interaction between poly(ethylene oxide) (PEO) and CO2 accounts for the high selectivity. Effects of coating solution concentration and coating time on gas separation performance have been investigated and the results have been optimized. To the best of our knowledge, this is the first polymeric composite hollow fiber membrane for hydrogen purification. The attractive gas separation performance of the newly developed membranes may indicate good potential for industrial applications. 相似文献
7.
The CO inhibition effect on H2 permeance through commercial Pd-based membranes was analysed by means of permeation measurements at different CO compositions (0–30% molar) and temperatures (593–723 K) with the aim to determine the increase of the membrane area in order to compensate the H2 flux reduction owing to the CO inhibition effect. The permeance of H2 fed with carbon monoxide was observed to decrease with respect to the case of pure hydrogen. At 647 K the H2 permeance of a pure feed of 316 μmol m−2 s−1 Pa−0.5 reduces progressively until 275 μmol m−2 s−1 Pa−0.5 when 15% or more of CO is present in the system, until it reaches a plateau at 20%. The inhibition effect occurring when CO is present in the feed stream reduces with the progressive temperature increase; the reduction of the permeance decreases exponentially by 23% at 593 K and by 3% at 723 K with 10% of CO. The inhibition effect is seen to be reversible. An H2 flux profile in a Sieverts' plot shows the effect produced by the increase of the CO composition along the Pd-based membrane length. The H2 flux profile allows the area of a Pd-based membrane to be evaluated in order to have the same permeate flow rate of H2 when it is fed with CO or as a pure stream. Moreover, a qualitative comparison between the H2 flux profiles and a previously proposed model has been carried out. 相似文献
8.
Solid Oxide Electrolyzer Cells (SOECs) are promising energy devices for the production of syngas (H2/CO) by H2O and/or CO2 electrolysis. Here we developed a Cu–Ce0.9Gd0.1O2−δ/Ce0.8Gd0.2O2−δ/Ba0.5Sr0.5Co0.8Fe0.2O3−δ-Ce0.8Gd0.2O2−δ cell and performed H2O and CO2 electrolysis experiments in the intermediate temperature range (600°C–700 °C). As a baseline, the cell was first tested in fuel cell operation mode; the sample shows a maximum power density peak of 104 mW cm−2 at 700 °C under pure hydrogen and air. H2O electrolysis testing revealed a steady production of hydrogen with a Faraday's efficiency of 32% at 700 °C at an imposed current density of −78 mA cm−2. CO production was observed during CO2 electrolysis but higher cell voltages were required. A lower efficiency of about 4% was obtained at 700 °C at an imposed current density of −660 mA cm−2. These results confirm that syngas production is feasible by water and carbon dioxide electrolysis but further improvements from both the manufacturing and the electrocatalytic aspects are needed to reach higher yields and efficiencies. 相似文献
9.
Raúl Sanz José Antonio CallesDavid Alique Laura Furones 《International Journal of Hydrogen Energy》2014
In this work, H2 production via catalytic water gas shift reaction in a composite Pd membrane reactor prepared by the ELP “pore-plating” method has been carried out. A completely dense membrane with a Pd thickness of about 10.2 μm over oxidized porous stainless steel support has been prepared. Firstly, permeation measurements with pure gases (H2 and N2) and mixtures (H2 with N2, CO or CO2) at four different temperatures (ranging from 350 to 450 °C) and trans-membrane pressure differences up to 2.5 bar have been carried out. The hydrogen permeance when feeding pure hydrogen is within the range 2.68–3.96·10−4 mol m−2 s−1 Pa−0.5, while it decreases until 0.66–1.35·10−4 mol m−2 s−1 Pa−0.5 for gas mixtures. Furthermore, the membrane has been also tested in a WGS membrane reactor packed with a commercial oxide Fe–Cr catalyst by using a typical methane reformer outlet (dry basis: 70%H2–18%CO–12%CO2) and a stoichiometric H2O/CO ratio. The performance of the reactor was evaluated in terms of CO conversion at different temperatures (ranging from 350 °C to 400 °C) and trans-membrane pressures (from 2.0 to 3.0 bar), at fixed gas hourly space velocity (GHSV) of 5000 h−1. At these conditions, the membrane maintained its integrity and the membrane reactor was able to achieve up to the 59% of CO conversion as compared with 32% of CO conversion reached with conventional packed-bed reactor at the same operating conditions. 相似文献
10.
D.Y. Aceves Olivas M.R. Baray Guerrero M.A. Escobedo Bretado M. Marques da Silva Paula J. Salinas Gutiérrez V. Guzmán Velderrain A. López Ortiz V. Collins-Martínez 《International Journal of Hydrogen Energy》2014
This paper presents results of thermodynamic analysis and experimental evaluation of hydrogen production by steam reforming of ethanol (SRE) combined with CO2 absorption using a mixture of a solid absorbent (CaO, CaO*MgO and Na2ZrO3) and a Ni/Al2O3 catalyst. Thermodynamic analysis results indicate that a maximum of 69.5% H2 (dry basis) is feasible at 1 atm, H2O/C2H5OH = 6 (molar ratio) and T = 600 °C. whereas, the addition of a CO2 absorbent at 1 atm, T = 600 °C and H2O/C2H5OH/Absorbent = 6:1:2.5, produced a H2 concentration of 96.6, 94.1, and 92.2% using CaO, CaO*MgO, and Na2ZrO3, respectively. SRE experimental evaluation achieved a maximum of 60% H2. While combining SRE and a CO2 absorbent exhibited a concentration of 96, 94, and 90% employing CaO, CaO*MgO, and Na2ZrO3, respectively at 1 atm, T = 600 °C, SV = 414 h−1 and H2O/C2H5OH/absorbent = 6:1:2.5 (molar ratio). 相似文献
11.
Vanesa Gil Jonas Gurauskis Christian Kjølseth Kjell Wiik Mari-Ann Einarsrud 《International Journal of Hydrogen Energy》2013
Asymmetric supported La28 − xW4 + xO54 + 3x/2 (La/W ≈ 5.6) membranes were investigated for their hydrogen permeation properties as a function of temperature and feed gas conditions. Dense membranes of thickness 25–30 μm supported on substrates with 25 and 40 vol.% porosity were compared. Above 850 °C under dry conditions, the hydrogen permeation rate was approximately constant as a function of temperature due to low concentration of protons in the material at high temperatures. Under humid conditions and above 960 °C enhanced permeation rates were observed. A hydrogen permeation as high as 0.14 NmL min−1 cm−2 was recorded at 1000 °C with 10 vol.% H2 (2.5 vol.% H2O) as feed gas. 相似文献
12.
The development of compact hydrogen separator based on membrane technology is of key importance for hydrogen energy utilization, and the Pd-modified carbon membranes with enhanced hydrogen permeability were investigated in this work. The C/Al2O3 membranes were prepared by coating and carbonization of polyfurfuryl alcohol, then the palladium was introduced through impregnation–precipitation and colloid impregnation methods with a PdCl2/HCl solution and a Pd(OH)2 colloid as the palladium resources, and the reduction was carried out with a N2H4 solution. The resulting Pd/C/Al2O3 membranes were characterized by means of SEM, EDX, XRD, XPS and TEM, and their permeation performances were tested with H2, CO2, N2 and CH4 at 25 °C. Compared with the colloid impregnation method, the impregnation–precipitation is more effective in deposition of palladium clusters inside of the carbon layer, and this kind of Pd/C/Al2O3 membranes exhibits excellent hydrogen permeability and permselectivity. Best hydrogen permeance, 1.9 × 10−7 mol/m2 s Pa, is observed at Pd/C = 0.1 wt/wt, and the corresponding H2/N2, H2/CO2 and H2/CH4 permselectivities are 275, 15 and 317, respectively. 相似文献
13.
《International Journal of Hydrogen Energy》2022,47(65):28025-28033
Using molecular dynamics (MD) simulations, we investigated the performance of graphenylene membrane with functionalized nanopore in the H2/CH4 separation. In the present work, we studied the impact of functionalized nanopore, system temperature (298, 323, and 348 K), applied difference pressure (up to 2 MPa), and feed composition on the H2/CH4 separation performance. The passage of gas molecules across the nanopore was monitored within the simulations, and the permeance was determined under applied conditions. The results revealed that the size of gas molecules and its interaction with the membrane nanopore are two important factors in the separation performance of H2/CH4 gas mixture. It is also found that H2 molecules can easily pass through the studied membranes, whereas no CH4 molecule was seen in the permeate side, which confirms the ultrahigh selectivity of H2 over CH4. Furthermore, the maximum H2 permeance of 1.95 × 105 GPU through the pore 1 was obtained at 1.5 MPa, which was higher than that of 1.93 × 105 GPU through pore 2. The results also demonstrated that the system temperature doesn't have any effect on the membrane performance. To this end, the permeance of H2 molecules through the studied membranes obviously increased with raising the ration of H2 molecules in the feed composition. Due to high selectivity and permeance, the graphenylene membrane with functionalized nanopore is expected to have promising applications in hydrogen separation from H2/CH4 mixed gas. 相似文献
14.
Perovskite-type oxide catalysts LaNiO3 and La1−xCexNiO3 (x ≤ 0.5) were prepared by the Pechini method and used as catalysts for carbon dioxide reforming of methane to form synthesis gas (H2 + CO). The gaseous reactants consisted of CO2 and CH4 in a molar ratio of 1:1. At a GHSV of 10,000 hr−1, CH4 conversion over LaNiO3 catalyst increased from 66% at 600 °C to 94% at 800 °C, while CO2 conversion increased from 51% to 92%. The achieved selectivities of CO and H2 were 33% and 57%, respectively, at 600 °C. To prevent the deposition of carbon and the sintering nickel species, some of the Ni in perovskite-type oxide catalyst was substituted by Ce. Ce provided lattice oxygen vacancies, which activated C–H bonds, and increased the selectivity of H2 to 61% at 600 °C. XRD analysis indicates that the catalyst exhibited a typical perovskite spinel structure and formed La2O2CO3 phases after CO2 reforming. The FE-SEM results reveal carbon whisker of the LaNiO3 catalyst and the BET analysis indicates that the specific surface area increases after the reforming reaction. The H2-TPR results confirm that Ce metals can store and provide oxygen. 相似文献
15.
Soo Jin Kim Byung-Seok Lee Sang Hyun Ahn Jun Young Han Hee Young Park Sung Hyun Kim Sung Jong Yoo Hyoung-Juhn Kim EunAe Cho Dirk Henkensmeier Suk Woo Nam Tae-Hoon Lim Soo-Kil Kim Wansoo Huh Jong Hyun Jang 《International Journal of Hydrogen Energy》2013
Carbon capture and storage (CCS) technologies have been intensively researched and developed to cope with climate change, by reducing atmospheric CO2 concentration. The electrochemical hydrogen pumps with phosphoric acid doped polybenzimidazole (PBI) membrane are evaluated as a process to concentrate CO2 and produce pure H2 from anode outlet gases (H2/CO2 mixture) of molten carbonate fuel cells (MCFC). The PBI-based hydrogen pump without humidification (160 °C) can provide higher hydrogen separation performances than the cells with perfluorosulfonic-acid membranes at a relative humidity of 43% (80 °C), suggesting that the pre-treatment steps can be decreased for PBI-based systems. With the H2/CO2 mixture feed, the current efficiency for the hydrogen separation is very high, but the cell voltage increase, compared to the pure hydrogen operation, mainly due to the larger polarization resistance at electrodes, as confirmed by electrochemical impedance spectroscopy (EIS). The performance evaluation with various Pt loadings indicates that the hydrogen oxidation reaction at anodes is rate determining, and therefore the Pt loading at cathodes can be decreased from 1.1 mg/cm2 to 0.2 mg/cm2 without significant performance decay. The EIS analysis also confirms that the polarization resistances are largely dependent on the Pt loading in anodes. 相似文献
16.
A series of Y2O3-promoted NiO/SBA-15 (9 wt% Ni) catalysts (Ni:Y weight ratio = 9:0, 3:1, 3:2, 1:1) were prepared using a sol–gel method. The fresh as well as the catalysts used in CO2 reforming of methane were characterized using N2-physisorption, XRD, FT-IR, XPS, UV, HRTEM, H2-TPR, O2-TPD and TG techniques. The results indicate that upon Y2O3 promotion, the Ni nanoparticles are highly dispersed on the mesoporous walls of SBA-15 via strong interaction between metal ions and the HO–Si-groups of SBA-15. The catalytic performance of the catalysts were evaluated at 700 °C during CH4/CO2 reforming at a gas hourly space velocity of 24 L gcat−1 h−1(at 25 °C and 1 atm) and CH4/CO2molar ratio of 1. The presence of Y2O3 in NiO/SBA-15 results in enhancement of initial catalytic activity. It was observed that the 9 wt% Y–NiO/SBA-15 catalyst performs the best, exhibiting excellent catalytic activity, superior stability and low carbon deposition in a time on stream of 50 h. 相似文献
17.
Igor Luisetto Simonetta Tuti Elisabetta Di Bartolomeo 《International Journal of Hydrogen Energy》2012
Co/CeO2 (Co 7.5 wt.%), Ni/CeO2 (Ni 7.5 wt.%) and Co–Ni/CeO2 (Co 3.75 wt.%, Ni 3.75 wt.%) catalysts were prepared by surfactant assisted co-precipitation method. Samples were characterized by X-Ray diffraction, BET surface areas measurements, temperature programmed reduction and tested for the dry reforming of methane CH4 + CO2 → 2CO + 2H2 in the temperature range 600–800 °C with a CH4:CO2:Ar 20:20:60 vol.% feed mixture and a total flow rate of 50 cm3 min−1 (GHSW = 30,000 mL g−1 h−1). The bimetallic Co–Ni/CeO2 catalyst showed higher CH4 conversion in comparison with monometallic systems in the whole temperature range, being 50% at 600 °C and 97% at 800 °C. H2/CO selectivity decreased in the following order: Co–Ni/CeO2 > Ni/CeO2 > Co/CeO2. Carbon deposition on spent catalysts was analyzed by thermal analysis (TG-DTA). After 20 h under stream at 750 °C, cobalt-containing catalysts, Co/CeO2 and Co–Ni/CeO2, showed a stable operation in presence of a deposited amorphous carbon of 6 wt.%, whereas Ni/CeO2 showed an 8% decrease of catalytic activity due to a massive presence of amorphous and graphitic carbon (25 wt.%). 相似文献
18.
Jungdeok ParkJing Zou Heechul YoonGuntae Kim Jong Shik Chung 《International Journal of Hydrogen Energy》2011,36(10):6184-6193
Zinc-doped barium strontium cobalt ferrite (Ba0.5Sr0.5Co0.2−xZnxFe0.8O3−δ (BSCZF), x = 0, 0.05, 0.1, 0.15, 0.2) powders with various proportions of zinc were prepared using the ethylenediamine tetraacetic acid (EDTA)-citrate method with repeated ball-milling and calcining. They were then evaluated as cathode materials for solid oxide fuel cells at intermediate temperatures (IT-SOFCs) using XRD, H2-TPR, SEM, and electrochemical tests. By varying the zinc doping (x) from zero to 0.2 (as a substitution for cobalt which ranged from zero to 100%), it was found that the lowest doping of 0.05 (BSCZF05) resulted in the highest electrical conductivity of 30.7 S cm−1 at 500 °C. The polarization resistances of BSCZF05 sintered at 950 °C were 0.15 Ω cm2, 0.28 Ω cm2 and 0.59 Ω cm2 at 700 °C, 650 °C and 600 °C, respectively. The resistance decreased further by about 30% when Sm0.2Ce0.8O2−δ (SDC) electrolyte particles were incorporated and the sintering temperature was increased to 1000 °C. Compared to BSCF without zinc, BSCZF experienced the lowest decrease in electrochemical properties when the sintering temperature was increased from 950 °C to 1000 °C. This decrease was due to an increase in thermal stability and a minimization in the loss of some cobalt cations without a decrease in the electrical conductivity. Using a composite cathode of BSCZF05 and 30 wt.% of SDC, button cells composed of an Ni-SDC support with a 30 μm dense SDC membrane exhibited a maximum power density of 605 mW cm−2 at 700 °C. 相似文献
19.
P. Bakonyi N. Nemestóthy J. Ramirez G. Ruiz-Filippi K. Bélafi-Bakó 《International Journal of Hydrogen Energy》2012
In this work continuous hydrogen production by Escherichia coli (XL1-BLUE) and its purification by membrane gas separation were studied. Firstly, a kinetic investigation was performed on formate supplemented broth in order to determine exponential growth phase (5–7 h) while the most intense hydrogen fermentation takes place. Furthermore, important process design parameters such as saturation constant and maximal growth rate were calculated (KS = 0.77 g l−1, μmax = 0.39 h−1). Afterward, based on the kinetic study, continuous hydrogen fermentations using cultures of E. coli (XL1-BLUE) were carried out in a CSTR reactor configuration applying various hydraulic retention times (HRT) related to both exponential and stationary growth period (5 h, 7 h, 9 h). The results indicated that highest hydrogen yield (0.26 mmol H2/mmol formate added) and productivity (5.1 mmol H2 l−1 d−1) could be achieved by applying HRT = 7 h that does not allow the living cells to reach stationary phase. In addition to hydrogen production, the concentration of bioH2 by polyimide membrane under different operational circumstances was investigated using pure and mixed gases, as well. The results of single gas experiments indicated that increasing the temperature has positive effect on separation efficiency. Moreover, the influence of retentate and feed flow ratio (QR/QF) was studied applying binary H2/CO2 gaseous mixture and it was found that polyimide membrane has high potential for H2 purification since 18% increase in H2 concentration and 22% decrease in CO2 content could be attained in the permeate by a one-step separation process. 相似文献
20.
Liang Zhou Jianhua Yang Gang Li Jinqu Wang Yan Zhang Jinming Lu Dehong Yin 《International Journal of Hydrogen Energy》2014
An effective steam-assisted conversion (SAC) seeding method was proposed for the growth of a thin and high-quality SAPO-34 membrane on a low-cost and coarse macroporous α-Al2O3 tubular support. This seeding technique was composed of depositing the seeds-containing paste on a support and transforming the paste into continuous and compact seed layer by the SAC process. The paste could serve as the binder to prevent small seeds penetrating into the support. With the aid of the perfect seed layer, a high-quality SAPO-34 membrane with the thickness about 4 μm was synthesized by secondary growth. The as-synthesized membrane exhibited a high H2 permeance of 6.96 × 10−6 mol m−2 s−1 Pa−1 at room temperature, with H2/CO2, H2/N2, H2/CH4, H2/C2H6, H2/C3H8, H2/n-C4H10 and H2/i-C4H10 ideal selectivities of 1.83, 7.58, 14.80, 18.24, 26.51, 40.15 and 53.02, respectively. 相似文献