International Journal of Energy Research, Vol.43, No.9, 4959-4966, 2019
Study on hydrogen permeation of Ni-BaZr0.1Ce0.7Y0.2O3-delta asymmetric cermet membrane
Early on, we had reported the preparation process of Ni-BaZr0.1Ce0.7Y0.2O3-delta asymmetric cermet membrane (Ni-BZCY ACM). In this work, we further optimized the sintering procedure and investigated the effect of water vapor in feed gas, operating time, H-2 concentration difference across the membrane, and dense layer thickness of Ni-BZCY ACM on hydrogen permeation behaviors. Adding the water vapor into feed gas can effectively improve the hydrogen permeability due to the appearance of a new proton hydration path. An almost unchanged hydrogen permeation output during 100-hour testing confirms the membrane stability under operating condition. More important, the rate-limiting step for hydrogen permeation process was elucidated according to the relationship between dense membrane thicknesses and hydrogen permeation fluxes. The surface exchange kinetics predominated permeation performance when the thickness is down to 50 mu m, especially at a lower temperature, which was found for the first time for Ni-BZCY cermet membrane. This result indicated that enhancing exchange kinetics of membrane surface became significant and indispensable for higher hydrogen separation efficiency.