Oxygen permeation through thin mixed‐conducting solid oxide membranes

in Wiley InterScience (www.interscience.wiley.com).Thin palladium membranes of different thicknesses were prepared on sol-gel derived mesoporous c-alumina/a-alumina and yttria-stabilized zirconia/a-alumina supports by a method combining sputter deposition and electroless plating. The effect of metalsupport interface on hydrogen transport permeation properties was investigated by comparing hydrogen permeation data for these membranes measured under different conditions. Hydrogen permeation fluxes for the Pd/c-Al 2 O 3 /a-Al 2 O 3 membranes are significantly smaller than those for the Pd/YSZ/a-Al 2 O 3 membranes under similar conditions. As the palladium membrane thickness increases, the difference in permeation fluxes between these two groups of membranes decreases and the pressure exponent for permeation flux approaches 0.5 from 1. Analysis of the permeation data with a permeation model shows that both groups of membranes have similar hydrogen permeability for bulk diffusion, but the Pd/c-Al 2 O 3 /a-Al 2 O 3 membranes exhibit a much lower surface reaction rate constant with higher activation energy, due possibly to the formation of Pd-Al alloy, than the Pd/YSZ/a-Al 2 O 3 membranes.

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“…According to the model derived by Lin and coworkers, 43,44 H 2 permeation through a thin Pd membrane can be described by the following equations.…”

Section: Methodsmentioning

confidence: 99%

Effect of metal‐support interface on hydrogen permeation through palladium membranes

et al. 2009

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“…Although a multistep kinetic mechanism written in terms of more elementary reactions exist [39,40], the expression (1) is sufficient to model the overall surface exchange process on both sides of the membrane [41,42].…”

Section: Surface Exchangementioning

confidence: 99%

“…As a result, the backward reaction of surface exchange, expressed in (1), becomes pseudo-zero order at steady state under isothermal operations [45]. Then, based on the global reaction (1) and the reaction rate expression (2), the oxygen permeation rate by the surface exchange reaction on each side of the membrane can be expressed as, Depending on how the expressions in (3) and (4) are simplified or the reaction rate (2) is approximated, different empirical correlations for the surface exchange processes have been proposed [41,43,44,46].…”

Section: Surface Exchangementioning

confidence: 99%

Numerical simulation of ion transport membrane reactors: Oxygen permeation and transport and fuel conversion

Hong

Kirchen

Ghoniem

2012

Journal of Membrane Science

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Ion transport membrane (ITM) based reactors have been suggested as a novel technology for several applications including fuel reforming and oxy-fuel combustion, which integrates air separation and fuel conversion while reducing complexity and the associated energy penalty. To utilize this technology more effectively, it is necessary to develop a better understanding of the fundamental processes of oxygen transport and fuel conversion in the immediate vicinity of the membrane. In this paper, a numerical model that spatially resolves the gas flow, transport and reactions is presented. The model incorporates detailed gas phase chemistry and transport. The model is used to express the oxygen permeation flux in terms of the oxygen concentrations at the membrane surface given data on the bulk concentration, which is necessary for cases when mass transfer limitations on the permeate side are important and for reactive flow modeling. The simulation results show the dependence of oxygen transport and fuel conversion on the geometry and flow parameters including the membrane temperature, feed and sweep gas flow, oxygen concentration in the feed and fuel concentration in the sweep gas.

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“…model by analyzing the diffusion of oxygen vacancies through membranes and the oxygen exchange reactions at the interfaces. 17,18 Three permeation resistances can be determined by the regression analysis of their model parameters, and a clear map can be easily drawn to show how the temperature and oxygen pressure affect the distribution of permeation resistances. In developing their model, four assumptions were proposed: (1) the electronic conductivity is much greater than the ionic conductivity; (2) the diffusion coefficient of oxygen vacancies does not change with oxygen pressure; (3) the forward and reverse reactions have the same rate constant, and (4) the law of mass action can be used for the oxygen exchange reactions on both sides.…”

Section: Introductionmentioning

confidence: 99%

Permeation model and experimental investigation of mixed conducting membranes

Zhu

Liu

et al. 2011

AIChE Journal

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A simple oxygen permeation model was developed based on the theoretical analysis of the role of interfaces of mixed conducting membranes. The developed model equations contain three resistance constants, which can be determined by correlating oxygen permeation flux to oxygen partial pressure on each side. A series of experimental measurements of oxygen fluxes of Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3À membranes over a wide range of temperature and oxygen partial pressures were tested for the regression of three resistance constants with good correlation (R > 0.997). With this model, the interfacial exchange resistances of each side can be well distinguished from the bulk-diffusion resistance under a wide-temperature range. The kinetics parameters, including interfacial exchange coefficients on each side and ionic diffusion coefficient, can be obtained through the three resistance constants. Parametric studies can predict the influences of membrane thickness, oxygen partial pressures on oxygen flux, distribution of permeation resistances, and characteristic thickness.

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Oxygen permeation through thin mixed‐conducting solid oxide membranes

Cited by 150 publications

References 26 publications

Effect of metal‐support interface on hydrogen permeation through palladium membranes

Effect of metal‐support interface on hydrogen permeation through palladium membranes

Numerical simulation of ion transport membrane reactors: Oxygen permeation and transport and fuel conversion

Permeation model and experimental investigation of mixed conducting membranes

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