Prediction of CO_2/H_2 Separation Properties of NaY Zeolite Membranes under Multicomponent Mixture Conditions

摘要

The separation performances of a NaY-type zeolite membranes- -were evaluated in terms of permeance and selectivity as a function of temperature and-feed pressure by coupling a modified Knudsen mechanism with the surface diffusion with a multicomponent approach. After model validation in a-wide temperature range (0-400°C) using slngle-gas experimental data from the literature [2-3], the model was applied to predict the permeation performances in binary mixture conditions, which showed a permeation,behaviour quite different from the single-gas case. As the main result, CO_2 and H_2 permeation trends with temperature are found to be different from each other, with the former being decreasing and the latter increasing/with it This results in a selectivity decreasing with temperature,-forecasting that adopting temperature below 0°C at the/low pressure values considered could importantly -enhance the CO_2/H_2 separation efficiency thanks to the|Stronger blocking effect caused by CO_2 towards the H_2 permeation. Furthermore, the feed pressure is found to decrease/the permeance of both CO_2 and H_2, whereas their selectivity remains basically constant in the feed pressure range of 400-1000 kPa.