GAS SEPARATION BY SILICON BASED INORGANIC MEMBRANE AT HIGH-TEMPERATURE

The permeabilities of several gases (H-2, N2, O2, Ar, He, H2S, CO2 and C3H6) through a silicon based inorganic membrane have been measured in the pressure range of 10 to 50 psig and in the temperature range of 25 to 700-degrees-C. The data can be interpreted adequately based on a modified activated diffusion equation. For a given membrane, the activated diffusion (or adsorbate flow) increases with increase in pressure. This phenomenon can be quantitatively represented by a parameter which is the intensity of adsorption in the Freundlich isotherm. The relative energy difference between the minimum potential energy and the activation energy of activated diffusion for an adsorbed molecule plays an important role in the temperature dependency of the adsorbate flow. The total permeability and separation factor for a binary gas mixture consisting of nitrogen and propene have been measured at different operating temperatures (30-205-degrees-C) and pressures (10-35 psig). Propene enrichment is favored if both pressure and temperature are decreased. The experimental data and the calculated separation factors show similar trends.