Modeling of hydrogen permeation for Ni-ceramic proton conductor composite membrane with symmetric structure

A model for symmetric cermets hydrogen permeation membrane is developed, which makes it possible to correlate permeation performance directly to measurable variables, such as experimental conditions and geometric parameters of membrane. The model is successfully applied in Ni-BaCe1-x-yZryYxO3-delta cermets membranes, with the usage of percolation theory to describe the effective properties of the binary composite. The resistances from both interfacial exchange and bulk diffusion, which provide a possible approach to the identification of the rate limiting steps, are discussed. The flux through nickel phase is also considered to decide the conditions under which this flux is remarkable or neglectable. Besides, bulk diffusion coefficient, which is difficult to measure in experiment, can be estimated by simply fitting hydrogen permeation rate using this model. The general trends are in good agreement with experimental results, showing the potential utilization of this model in the analysis of hydrogen separation membrane. (c) 2012 Elsevier B.V. All rights reserved.