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Toraj Mohammadi - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation and mathematical modeling of co2 sequestration from co2 ch4 Gaseous Mixture using mea and tea aqueous absorbents through polypropylene hollow fiber membrane contactor
Journal of Membrane Science, 2018Co-Authors: Ali Taghvaie Nakhjiri, Amir Heydarinasab, Omid Bakhtiari, Toraj MohammadiAbstract:Abstract In the current study, experimental and mathematical results of a counter-current contact between CO2/CH4 Gaseous Mixture and aqueous liquid absorbents (MEA and TEA) through a microporous polypropylene hollow fiber membrane contactor are presented to evaluate the sequestration percentage of CO2 acidic pollutant from Gaseous Mixture. One of the aims of this paper is to experimentally and mathematically study the effects of gas flow rate, aqueous liquid absorbents' flow rate and also inlet CO2 concentration on the removal efficiency of CO2. In order to carry out this, a two dimensional mathematical model is developed to predict the experimental results. The experimental results show that MEA absorbent has higher superiority for efficient removal of CO2 acidic gas compared to TEA absorbent. Based on the experimental results, the sequestration efficiency of CO2 from Gaseous Mixture applying MEA and TEA aqueous absorbents is about 92% and 62%, respectively. The simulated results of CO2 sequestration in wide ranges of gas flow rate, inlet CO2 concentration and liquid absorbents' flow rate demonstrate an excellent agreement with those of experimentally measured ones with average absolute relative errors (AAREs) of 4.3%, 4.4% and 3.6% for employing MEA and 6.9%, 3.4% and 5.2% for using TEA absorbents, respectively. Additionally, this article aims to study the influence of momentous operational parameters such as number of fibers, module length and also membrane porosity and tortuosity on the CO2 separation efficiency. Based on the experimental and the numerical simulated results, increase in the gas flow rate, the membrane tortuosity and the CO2 inlet concentration significantly deteriorates the sequestration efficiency of CO2 while increment of the fibers counts, the membrane module length, the membrane porosity and the liquid flow rate positively encourages the CO2 sequestration percentage.
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the effect of membrane pores wettability on co2 removal from co2 ch4 Gaseous Mixture using naoh mea and tea liquid absorbents in hollow fiber membrane contactor
Chinese Journal of Chemical Engineering, 2018Co-Authors: Ali Taghvaie Nakhjiri, Amir Heydarinasab, Omid Bakhtiari, Toraj MohammadiAbstract:Abstract The present paper renders a modeling and a 2D numerical simulation for the removal of CO2 from CO2/CH4 Gaseous stream utilizing sodium hydroxide (NaOH), monoethanolamine (MEA) and triethanolamine (TEA) liquid absorbents inside the hollow fiber membrane contactor. Counter-current arrangement of absorbing agents and CO2/CH4 Gaseous Mixture flows are implemented in the modeling and numerical simulation. Non-wetting and partial wetting modes of operation are considered where in the partial wetting mode, CO2/CH4 Gaseous Mixture and liquid absorbents fill the membrane pores. The deteriorated removal of CO2 in the partial wetting mode of operation is mainly due to the mass transfer resistance imposed by the liquid in the pores of membrane. The validation of numerical simulation is done based on the comparison of simulation results of CO2 removal using NaOH and experimental data under non-wetting mode of operation. The comparison illustrates a desirable agreement with an average deviation of less than 5%. According to the results, MEA provides higher efficiency for CO2 removal in comparison with the other liquid absorbents. The order for CO2 removal performance is MEA > NaOH > TEA. The influence of non-wetting and partial wetting modes of operation on CO2 removal are evaluated in this article as one of the novelties. Besides, the percentage of CO2 sequestration as a function of gas velocity for various percentages of membrane pores wetting ranging from 0 (non-wetting mode of operation) to 100% (complete wetting mode of operation) is studied in this research paper, which can be proposed as the other novelty. The results indicate that increase in some operational parameters such as module length, membrane porosity and absorbents concentration encourage the removal percentage of CO2 from CO2/CH4 Gaseous Mixture while increasing in membrane tortuosity, gas velocity and initial CO2 concentration has unfavorable influence on the separation efficiency of CO2.
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modeling and simulation of co2 separation from co2 ch4 Gaseous Mixture using potassium glycinate potassium argininate and sodium hydroxide liquid absorbents in the hollow fiber membrane contactor
Journal of environmental chemical engineering, 2018Co-Authors: Ali Taghvaie Nakhjiri, Amir Heydarinasab, Omid Bakhtiari, Toraj MohammadiAbstract:Abstract The emission of CO2 greenhouse gas is one of the most momentous causes of environmental problems such as global warming. Hence, the sequestration of CO2 acid gas from Gaseous streams is considered as a mandatory process to control the detrimental impressions of CO2 emission. In the present investigation, a mathematical modeling and a two dimensional comprehensive simulation is developed with the aim of evaluating the removal performance of CO2 acid gas from CO2/CH4 Gaseous Mixture. As the novelty, potassium argininate (PA), potassium glycinate (PG) and sodium hydroxide (NaOH) are used as promising liquid solvents in the hollow fiber membrane contactor (HFMC) and the best absorbing agent for capturing CO2 is introduced. The validation of model predictions is implemented based on the comparison of simulation results of CO2 and experimental data using sodium hydroxide (NaOH) in a wide range of absorbent temperature and liquid velocity. Comparison of experimental data and simulation results for CO2 flux in wide ranges of absorbent (NaOH) temperature and absorbent velocity illustrates excellent agreements with average deviations of less than 4% and 3.7%, respectively. On the basis of simulation results, potassium argininate (PA) shows higher CO2 separation efficiency compared with the other liquid solvents. The order for CO2 separation rate is PA > PG > NaOH. The results imply that increment in the operational parameters such as porosity, module length and liquid absorbents velocity positively affect the separation percentage of CO2 while, increasing in gas velocity, membrane tortuosity and initial concentration of CO2 deteriorate the separation efficiency of CO2, considerably.
Denize Kalempa - One of the best experts on this subject based on the ideXlab platform.
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heat flux between parallel plates through a binary Gaseous Mixture over the whole range of the knudsen number
Physica A-statistical Mechanics and Its Applications, 2007Co-Authors: Felix Sharipov, Liliana Gramani M Cumin, Denize KalempaAbstract:The heat flux problem for a binary Gaseous Mixture confined between two parallel plates with different temperatures is studied on the basis of the McCormack kinetic model equation, which was solved by the discrete velocity method. The calculations were carried out for three Mixtures of noble gases: neon–argon, helium–argon and helium–xenon. The heat flux and distributions of temperature, density and concentration were calculated for several values of rarefaction in the range from 0.01 to 40 and for three values of the concentration: 0.1,0.5 and 0.9. The numerical data together with an analytical solution based on the temperature jump boundary condition cover the whole range of the gas rarefaction beginning from the free-molecular regime to the hydrodynamic one. It was shown that the heat flux significantly depends on the intermolecular interaction law.
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separation phenomena for Gaseous Mixture flowing through a long tube into vacuum
Physics of Fluids, 2005Co-Authors: Felix Sharipov, Denize KalempaAbstract:A Gaseous Mixture flow through a long tube into vacuum is considered assuming the pressure to be arbitrary at the tube entrance. Thus, the flow regime can vary from hydrodynamic at the entrance to free molecular at the tube exit. The distributions of density and concentration along the tube were obtained for the Mixture helium–xenon at various values of the concentration and rarefaction at the tube entrance. It was shown that the variation of the concentration along the tube can be significant. The flow rates of both species determining the chemical composition in the down flow container were calculated. An analysis of these data shows that the chemical composition in the down flow container can be different from that in the up flow one, i.e., the separation phenomenon takes place. The results presented in the article can be used in practice to avoid the separation phenomenon or to intensify it if necessary.
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plane couette flow of binary Gaseous Mixture in the whole range of the knudsen number
European Journal of Mechanics B-fluids, 2004Co-Authors: Felix Sharipov, Liliana Gramani M Cumin, Denize KalempaAbstract:Abstract The Couette flow of binary Gaseous Mixtures is studied on the basis of the McCormack model of the Boltzmann equation, which was solved numerically by the discrete velocity method. The calculations were carried out for three Mixtures of noble gases: neon–argon, helium–argon, and helium–xenon. The stress tensor and bulk velocity of both species were calculated for several values of the gas rarefaction in the range from 0.01 to 40 for three values of the molar concentrations: 0.1,0.5 and 0.9. The numerical solution together with an analytical solution based on the slip boundary condition cover the whole range of the gas rarefaction. It was showed that the Couette flow is weakly affected by the intermolecular interaction law.
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Gaseous Mixture flow between two parallel plates in the whole range of the gas rarefaction
Physica A-statistical Mechanics and Its Applications, 2004Co-Authors: S Naris, Denize Kalempa, Dimitris Valougeorgis, Felix SharipovAbstract:The flow of binary Gaseous Mixtures between two parallel plates driven by gradients of pressure, temperature and concentration is studied, based on the McCormack model of the Boltzmann equation. The coupled kinetic equations are solved numerically by the discrete velocity method. The mass flow, the heat flux and the diffusion flux, which are the Mixture quantities of practical importance, are expressed in terms of the so-called thermodynamic fluxes. The latter are written in a form that allows us to verify the Onsager–Casimir reciprocity relations. In addition, analytical expressions for these quantities are derived in the limit case of the hydrodynamic regime. Thus, the numerical solution together with these expressions provides the solution in the whole range of the gas rarefaction. The influence of the intermolecular interaction potential is also investigated by comparing the results for the rigid sphere model with those for a realistic potential. Numerical results are presented for two binary Mixtures of noble gases (Ne–Ar and He–Xe) for various values of the molar concentrations.
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discrete velocity modelling of Gaseous Mixture flows in mems
Superlattices and Microstructures, 2004Co-Authors: S Naris, Felix Sharipov, Dimitris Valougeorgis, Denize KalempaAbstract:The need of developing advanced micro-electro-mechanical systems (MEMS) has motivated the study of fluid-thermal flows in devices with micro-scale geometries. In many MEMS applications the Knudsen number varies in the range from 10 −2 to 10 2 . This flow regime can be treated neither as a continuum nor as a free molecular flow. In order to describe these flows it is necessary to implement the Boltzmann equation (BE) or simplified kinetic model equations. The aim of the present work is to propose an efficient methodology for solving internal flows of binary Gaseous Mixtures in rectangular channels due to small pressure gradients over the whole range of the Knudsen number. The complicated collision integral term of the BE is substituted by the kinetic model proposed by McCormack for Gaseous Mixtures. The discrete velocity method is implemented to solve in an iterative manner the system of the kinetic equations. Even more the required computational effort is significantly reduced, by accelerating the convergence rate of the iteration scheme. This is achieved by formulating a set of moment equations, which are solved jointly with the transport equations. The velocity profiles and the flow rates of three different binary Mixtures (He–Ar, Ne–Ar and He–Xe) in 2D micro-channels of various height to width ratios are calculated. The whole formulation becomes very efficient and can be implemented as an alternative methodology to the classical method of solving the Navier–Stokes equations with slip boundary conditions, which in any case is restricted by the hydrodynamic regime. © 2004 Elsevier Ltd. All rights reserved.
Ali Taghvaie Nakhjiri - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation and mathematical modeling of co2 sequestration from co2 ch4 Gaseous Mixture using mea and tea aqueous absorbents through polypropylene hollow fiber membrane contactor
Journal of Membrane Science, 2018Co-Authors: Ali Taghvaie Nakhjiri, Amir Heydarinasab, Omid Bakhtiari, Toraj MohammadiAbstract:Abstract In the current study, experimental and mathematical results of a counter-current contact between CO2/CH4 Gaseous Mixture and aqueous liquid absorbents (MEA and TEA) through a microporous polypropylene hollow fiber membrane contactor are presented to evaluate the sequestration percentage of CO2 acidic pollutant from Gaseous Mixture. One of the aims of this paper is to experimentally and mathematically study the effects of gas flow rate, aqueous liquid absorbents' flow rate and also inlet CO2 concentration on the removal efficiency of CO2. In order to carry out this, a two dimensional mathematical model is developed to predict the experimental results. The experimental results show that MEA absorbent has higher superiority for efficient removal of CO2 acidic gas compared to TEA absorbent. Based on the experimental results, the sequestration efficiency of CO2 from Gaseous Mixture applying MEA and TEA aqueous absorbents is about 92% and 62%, respectively. The simulated results of CO2 sequestration in wide ranges of gas flow rate, inlet CO2 concentration and liquid absorbents' flow rate demonstrate an excellent agreement with those of experimentally measured ones with average absolute relative errors (AAREs) of 4.3%, 4.4% and 3.6% for employing MEA and 6.9%, 3.4% and 5.2% for using TEA absorbents, respectively. Additionally, this article aims to study the influence of momentous operational parameters such as number of fibers, module length and also membrane porosity and tortuosity on the CO2 separation efficiency. Based on the experimental and the numerical simulated results, increase in the gas flow rate, the membrane tortuosity and the CO2 inlet concentration significantly deteriorates the sequestration efficiency of CO2 while increment of the fibers counts, the membrane module length, the membrane porosity and the liquid flow rate positively encourages the CO2 sequestration percentage.
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the effect of membrane pores wettability on co2 removal from co2 ch4 Gaseous Mixture using naoh mea and tea liquid absorbents in hollow fiber membrane contactor
Chinese Journal of Chemical Engineering, 2018Co-Authors: Ali Taghvaie Nakhjiri, Amir Heydarinasab, Omid Bakhtiari, Toraj MohammadiAbstract:Abstract The present paper renders a modeling and a 2D numerical simulation for the removal of CO2 from CO2/CH4 Gaseous stream utilizing sodium hydroxide (NaOH), monoethanolamine (MEA) and triethanolamine (TEA) liquid absorbents inside the hollow fiber membrane contactor. Counter-current arrangement of absorbing agents and CO2/CH4 Gaseous Mixture flows are implemented in the modeling and numerical simulation. Non-wetting and partial wetting modes of operation are considered where in the partial wetting mode, CO2/CH4 Gaseous Mixture and liquid absorbents fill the membrane pores. The deteriorated removal of CO2 in the partial wetting mode of operation is mainly due to the mass transfer resistance imposed by the liquid in the pores of membrane. The validation of numerical simulation is done based on the comparison of simulation results of CO2 removal using NaOH and experimental data under non-wetting mode of operation. The comparison illustrates a desirable agreement with an average deviation of less than 5%. According to the results, MEA provides higher efficiency for CO2 removal in comparison with the other liquid absorbents. The order for CO2 removal performance is MEA > NaOH > TEA. The influence of non-wetting and partial wetting modes of operation on CO2 removal are evaluated in this article as one of the novelties. Besides, the percentage of CO2 sequestration as a function of gas velocity for various percentages of membrane pores wetting ranging from 0 (non-wetting mode of operation) to 100% (complete wetting mode of operation) is studied in this research paper, which can be proposed as the other novelty. The results indicate that increase in some operational parameters such as module length, membrane porosity and absorbents concentration encourage the removal percentage of CO2 from CO2/CH4 Gaseous Mixture while increasing in membrane tortuosity, gas velocity and initial CO2 concentration has unfavorable influence on the separation efficiency of CO2.
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modeling and simulation of co2 separation from co2 ch4 Gaseous Mixture using potassium glycinate potassium argininate and sodium hydroxide liquid absorbents in the hollow fiber membrane contactor
Journal of environmental chemical engineering, 2018Co-Authors: Ali Taghvaie Nakhjiri, Amir Heydarinasab, Omid Bakhtiari, Toraj MohammadiAbstract:Abstract The emission of CO2 greenhouse gas is one of the most momentous causes of environmental problems such as global warming. Hence, the sequestration of CO2 acid gas from Gaseous streams is considered as a mandatory process to control the detrimental impressions of CO2 emission. In the present investigation, a mathematical modeling and a two dimensional comprehensive simulation is developed with the aim of evaluating the removal performance of CO2 acid gas from CO2/CH4 Gaseous Mixture. As the novelty, potassium argininate (PA), potassium glycinate (PG) and sodium hydroxide (NaOH) are used as promising liquid solvents in the hollow fiber membrane contactor (HFMC) and the best absorbing agent for capturing CO2 is introduced. The validation of model predictions is implemented based on the comparison of simulation results of CO2 and experimental data using sodium hydroxide (NaOH) in a wide range of absorbent temperature and liquid velocity. Comparison of experimental data and simulation results for CO2 flux in wide ranges of absorbent (NaOH) temperature and absorbent velocity illustrates excellent agreements with average deviations of less than 4% and 3.7%, respectively. On the basis of simulation results, potassium argininate (PA) shows higher CO2 separation efficiency compared with the other liquid solvents. The order for CO2 separation rate is PA > PG > NaOH. The results imply that increment in the operational parameters such as porosity, module length and liquid absorbents velocity positively affect the separation percentage of CO2 while, increasing in gas velocity, membrane tortuosity and initial concentration of CO2 deteriorate the separation efficiency of CO2, considerably.
Felix Sharipov - One of the best experts on this subject based on the ideXlab platform.
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ab initio simulation of Gaseous Mixture flow through an orifice
Vacuum, 2017Co-Authors: Felix SharipovAbstract:Abstract A flow of Mixture of rarefied gases through a thin orifice is calculated applying the direct simulation Monte Carlo method based on ab initio (AI) potential. The calculations have been carried out over a wide range of the gas rarefaction, for three values of the pressure ratio, and for five values of molar fraction with the numerical error of the flow rates less than 0.5%. A comparative analysis showed that the flow rate of Mixture has a behavior qualitatively different from that for a single gas. To check the accuracy of the hard sphere (HS) molecular model, additional simulations were carried out based on this model. It is found that the relative difference of the flow rate based on the AI potential from that obtained for the HS molecular model depends on many factors, namely, chemical composition, pressure ratio, and gas rarefaction. The discrepancy of the flow rates based on the two potentials reaches 3%. A comparison of the axial distributions of density, temperature and bulk velocity shows that the Mach disc for the Mixture considered here is weaker than that for single gas. Two-dimensional fields of density, temperature and local Mach number are presented for some values of the pressure ratio.
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heat flux between parallel plates through a binary Gaseous Mixture over the whole range of the knudsen number
Physica A-statistical Mechanics and Its Applications, 2007Co-Authors: Felix Sharipov, Liliana Gramani M Cumin, Denize KalempaAbstract:The heat flux problem for a binary Gaseous Mixture confined between two parallel plates with different temperatures is studied on the basis of the McCormack kinetic model equation, which was solved by the discrete velocity method. The calculations were carried out for three Mixtures of noble gases: neon–argon, helium–argon and helium–xenon. The heat flux and distributions of temperature, density and concentration were calculated for several values of rarefaction in the range from 0.01 to 40 and for three values of the concentration: 0.1,0.5 and 0.9. The numerical data together with an analytical solution based on the temperature jump boundary condition cover the whole range of the gas rarefaction beginning from the free-molecular regime to the hydrodynamic one. It was shown that the heat flux significantly depends on the intermolecular interaction law.
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Transport Phenomena Through Gaseous Mixtures in Microchannels
ASME 5th International Conference on Nanochannels Microchannels and Minichannels, 2007Co-Authors: Felix SharipovAbstract:In practice, one deals with Gaseous Mixtures more frequently than with a single gas. However, very few papers about the transport phenomena through a Mixture of rarefied gases were published. The aim of this work is to present a general approach to calculations of mass, heat and momentum transfer through Gaseous Mixtures over the whole range of the gas rarefaction. Results on some classical problems such as slip coefficient, Poiseuille flow, Couette flow and heat transfer are given for a Gaseous Mixture. A comparison with results corresponding to a single gas is carried out. Such a comparison shows the peculiarities of the transport phenomena in Mixtures.Copyright © 2007 by ASME
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separation phenomena for Gaseous Mixture flowing through a long tube into vacuum
Physics of Fluids, 2005Co-Authors: Felix Sharipov, Denize KalempaAbstract:A Gaseous Mixture flow through a long tube into vacuum is considered assuming the pressure to be arbitrary at the tube entrance. Thus, the flow regime can vary from hydrodynamic at the entrance to free molecular at the tube exit. The distributions of density and concentration along the tube were obtained for the Mixture helium–xenon at various values of the concentration and rarefaction at the tube entrance. It was shown that the variation of the concentration along the tube can be significant. The flow rates of both species determining the chemical composition in the down flow container were calculated. An analysis of these data shows that the chemical composition in the down flow container can be different from that in the up flow one, i.e., the separation phenomenon takes place. The results presented in the article can be used in practice to avoid the separation phenomenon or to intensify it if necessary.
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plane couette flow of binary Gaseous Mixture in the whole range of the knudsen number
European Journal of Mechanics B-fluids, 2004Co-Authors: Felix Sharipov, Liliana Gramani M Cumin, Denize KalempaAbstract:Abstract The Couette flow of binary Gaseous Mixtures is studied on the basis of the McCormack model of the Boltzmann equation, which was solved numerically by the discrete velocity method. The calculations were carried out for three Mixtures of noble gases: neon–argon, helium–argon, and helium–xenon. The stress tensor and bulk velocity of both species were calculated for several values of the gas rarefaction in the range from 0.01 to 40 for three values of the molar concentrations: 0.1,0.5 and 0.9. The numerical solution together with an analytical solution based on the slip boundary condition cover the whole range of the gas rarefaction. It was showed that the Couette flow is weakly affected by the intermolecular interaction law.
Gabjin Hwang - One of the best experts on this subject based on the ideXlab platform.
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stability of a silica membrane prepared by cvd using γ and α alumina tube as the support tube in the hi h2o Gaseous Mixture
Journal of Membrane Science, 2003Co-Authors: Gabjin Hwang, Hosang Choi, Kaoru OnukiAbstract:Abstract The stability of a silica membrane prepared by chemical vapor deposition (CVD) in the HI–H2O Gaseous Mixture was evaluated aiming at the application for hydrogen iodide decomposition in the thermochemical IS process. Porous α- and γ-alumina tubes having pore sizes of 100 and 10 nm, respectively, were modified by chemical vapor deposition using tetraethoxysilane as the Si source. H2/N2 selectivities of the modified membranes which were measured by single-component permeation experiment showed 50.4, 7.5, 63.7, 7.7 and 3.8 at 600 °C for the NS-1, NS-2, NS-3, NS-4 and S-1 membranes, respectively. Stability experiment in the HI–H2O Gaseous Mixture was carried out at 450 °C. The prepared membrane using γ-alumina as the support tube was more stable than that using α-alumina as the support tube. The S-1 membrane using α-alumina as the support tube showed the high stability in the HI–H2O Gaseous Mixture and had the high H2/HI selectivity (240–2600 at 300–600 °C) in the H2–H2O–HI (molar composition; 0.09:0.78:0.13) Gaseous Mixture after the stability test.
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separation of hydrogen from a h2 h2 ohi Gaseous Mixture using a silica membrane
Aiche Journal, 2000Co-Authors: Gabjin Hwang, Kaoru Onuki, Saburo ShimizuAbstract:Hydrogen separation characteristics of silica membranes prepared by chemical-vapor deposition (CVD)-in an H{sub 2}-H{sub 2}O-HI Gaseous Mixture were evaluated for the application to hydrogen iodide decomposition in the thermochemical iodine-sulfur (IS) process. Porous alumina tubes with a pore size of 10 nm and different gas-permeating-portion lengths [20 mm (S membranes) and 100 mm (L membranes)] were modified by CVD using tetraethoxysilane as the Si source. Pore closure was controlled by CVD to maintain high hydrogen permeance while lowering only HI permeance. At a certain point, CVD was stopped using He/N{sub 2} selectivity as the indicator of pore closure. H{sub 2}/N{sub 2} selectivities of the modified membranes, which were measured by a single-component permeation experiment, showed 53, 9.2, 4.1, 135, and 6.6 at 600 C for S1, S2, S3, L1, and L2 membranes, respectively. Separation experiments of the H{sub 2}-H{sub 2}O-HI Gaseous Mixture (a molar composition of 0.09:0.78:0.13) in the modified membranes were carried out at 300--600 C. Hydrogen permeance was almost the same as the single-component permeance. The separation factors of H{sub 2}-H{sub 2}O and H{sub 2}-HI were over 3 and 150, respectively. The S3 membrane showed the highest hydrogen permeance (on the order of 10{sup {minus}7} mol/Pa.m{sup 2}s) andmore » the highest separation factor of H{sub 2}-HI (650 at 450 C).« less
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hydrogen separation in h2 h2o hi Gaseous Mixture using the silica membrane prepared by chemical vapor deposition
Journal of Membrane Science, 1999Co-Authors: Gabjin Hwang, Kaoru Onuki, Saburo Shimizu, Haruhiko OhyaAbstract:Abstract Hydrogen separation in H 2 –H 2 O–HI Gaseous Mixture using the silica membrane prepared by CVD was evaluated aiming at the application for hydrogen iodide decomposition in the thermochemical IS process. Porous alumina tubes having pore size of 100 nm (M1) and 10 nm (M2) were modified by chemical vapor deposition using tetraethoxysilane as the Si source. Single-component permeance to He, H 2 , and N 2 was measured at 300–600°C. Hydrogen permeance of the modified membranes at a permeation temperature of 600°C was about 6×10 −9 mol/Pa m 2 s. H 2 /N 2 selectivities at 600°C were 5.2 and 160 for M1 and M2 membrane, respectively. Separation experiments of a H 2 –H 2 O–HI Mixture using the modified membranes were carried out at 300–600°C. Hydrogen permeances were almost the same as the single-component permeances, whereas HI permeances were below 1×10 −11 mol/Pa m 2 s. The hydrogen permeances were not changed after one day exposure in a Mixture of H 2 –H 2 O–HI with a molar composition of 0.23:0.65:0.12 at 450°C.