Papers by Keyword: Hydrogen Separation

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Authors: Supawan Vichaphund, Duangduen Atong
Abstract: This work aimed to investigate the effect of different sintering routes on properties of Ni-Al2O3 membrane. Alumina powder was mixed with 10 wt% nickel powder by dried ball-milling. Then, the mixture powder was uniaxially pressed to a bar shape and sintered via different sintering conditions. First route, the Ni-Al2O3 specimen was sintered at 1300°C for 2 h under air and then reduced at 900°C for 2 h under H2 atmosphere. Second route, the specimen was sintered at 1300°C for 2 h under argon. After sintering process, the physical and mechanical properties of membrane obtained from two routes were compared and discussed.
Authors: Hiroshige Matsumoto
Abstract: Hydrogen separation is one of the key techniques for the forthcoming hydrogen economy. This paper describes a possible electrochemical method and materials for hydrogen separation: mixed proton-electron-conducting membrane that can permeate hydrogen selectively from hydrogen-containing gases, such as reformed gases of hydrocarbons. Proton-conducting perovskite-type solid electrolytes are first introduced as the base material of the mixed conductor. Some transition metal-doped perovskites are shown to have a mixed conductivity of protonic and electronic charge carriers, revealed by electrochemical and X-ray-spectroscopic measurements.
Authors: Mettaya Kitiwan, Duangduen Atong
Abstract: The palladium membrane has been developed for high temperature separation of hydrogen from other syngas molecules. In this study, tubular α-alumina substrate was used as a support for increase mechanical strength for thin palladium membrane. Prior depositing of palladium film, a dip-coating of palladium nuclei was performed to cover the substrate. Afterward, surface of activated support was modified with a thin intermediate layer for improving adhesion between support and Pd membrane. Electroless plating of dense palladium membrane was achieved from the plating bath containing EDTA stabilized palladium complex and hydrazine. The microstructural characteristics of palladium membranes were analyzed.
Authors: Shu Min Fang, Jing Yang, Chu Shen Chen, Wei Liu
Abstract: Ni-BaCe0.9Y0.1O3-δ mixed protonic-electronic conductor can be used to separate hydrogen from syngas. Considering that water exists in syngas, it is necessary to evaluate the effect of moisture on chemical stability and hydrogen permeability of the cermet. In this paper, hydrogen permeation rates of Ni- BaCe0.9Y0.1O3-δ (40:60 in volume ratio) in different water partial pressures were measured at intermediate temperatures (600-750°C). It is found that hydrogen permeation rate of the cermet is highest at an appropriate water partial pressure. Samples after experiment were analyzed by XRD, ICP and pH value measurement, in which Ba(OH)2 and doped CeO2 were found. The reaction of water with samples resulting in insulating Ba(OH)2 and doped CeO2 is contributed to the decrease of hydrogen permeation in excessive water partial pressure.
Authors: Shinichi Yamaura, K. Wakoh, Hisamichi Kimura, Eiichiro Matsubara, Akihisa Inoue, Y. Shimpo, M. Nishida, O. Kajita
Authors: Y. Kim, Eun Bi Kim, Soo Ryong Kim, Moo Hyun Suh, Doo Jin Choi, Woo Teck Kwon
Abstract: Ceramic membranes having less than 1nm size pores have great potential for gas separation at high temperature due to their good thermal stability. Moreover, nanoporous silicon carbide membrane has potential application under hydrothermal condition at high temperature since it is highly stable at high temperature. In this research, nanoporous SiC membrane has been developed on porous alumina support using preceramic polymer. Pore size of the SiC membrane was controlled using polystylene(PS) as the pore forming agent. The SiC membrane having controlled pore size was characterized with SEM, EDS, FT-IR, XRD and pore size measurement. The hydrogen permeability and selectivity toward nitrogen gas of the developed membrane were 0.3 x 10-6 mole/ and 4.1, respectively. The nanoporous hydrogen selective SiC membrane shows promising application in membrane reactor for steam reforming reacti on of natural gas, water gas shift reactions and hydrogen separation from coal gasification such as Integrated Gasification Combined Cycle (IGCC).
Authors: Mohammed Nasir Kajama, Ngozi Claribelle Nwogu, Edward Gobina
Abstract: Gas permeation of hydrogen (H2) and nitrogen (N2) were obtained from 30 and 6000 nm pore diameter tubular commercial alumina ceramic membranes at 0.05 to 1.00 bar and 298 K. Flow rates of up to 3.279 and 2.296 l/min were obtained for H2 and N2 respectively. The ratio of H2/N2 flow rates were used to calculate H2/N2 selectivity. The experimental H2/N2 selectivities obtained were 1.85 and 1.43 for the 30 and 6000 nm respectively.
Authors: Mohammed Nasir Kajama, Ngozi Claribelle Nwogu, Edward Gobina
Abstract: Silica sol-gel membranes have been developed for moderate temperature (300 °C) separation of hydrogen (H2) from nitrogen (N2), methane (CH4) and argon (Ar) gas molecules. Tubular ceramic support with 15 nm nominal pore diameter and 45% porosity was modified by dip-coating method. Gas permeation characteristics were evaluated. Defect free silica layer over the substrate for hydrogen gas separation was obtained. Hydrogen gas permeate flux of 4.82x10-1 mol/sec m2 at 1.0 barg feed pressure was obtained. Selectivities of H2 over N2, CH4 and Ar of 3.07, 2.23 and 3.75 at 300 °C, 200 °C and 300 °C and 0.9 barg were obtained with the silica membranes. The gas permeation and the selectivity performance of the membrane were evaluated.
Authors: Yu Guo, Yu Jia Jin, Hong Mei Wu, Dong Xin Li, Li Dai Zhou, Qiang Qiang Chen, Xiong Fu Zhang
Abstract: Pd composite membranes were prepared on macroporous α-Al2O3 tubes modified by silicalite-1 zeolite. Permeation tests of the Pd composite membranes were performed at 773 K to observe the H2 permeance and H2/N2 selectivity. The H2 flux and ideal selectivity for Pd composite membrane was 0.120 mol m−2 s−1 and 450 under 0.1 MPa, respectively. The variation of the membrane surface after elevating temperature in N2 and air atmosphere was characterized in scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDS) analyses. As a result, it can be concluded that the formation of pinholes and defects on the membrane surface can be attributed to the oxidation of the Pd membrane.
Authors: Jie Shi, Di Jia, Bo Wen Cheng, Wei Min Kang, Xue Bai
Abstract: . In this paper, thin palladium (Pd) membranes, which are supported on alumina nanofiber nonwoven produced by electrospinning method, were prepared by electroless plating method. The influence of different pretreatment methods (iron wire activation) and reducing agent (sodium hypophosphite and hydrazine hydrate) on the structure of Pd membrane were studied. The morphology, surface element and crystal structure of the Pd membrane were investigated by SEM, EDS and XRD. The results showed that the compact Pd membrane was formed on the alumina nanofiber nonwoven when the pretreatment method of iron wire activation was adopted and the reducing agent of sodium hypophosphite was used, which will be applied widely in hydrogen separation area.
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