Pressure Swing Adsorption: Experimental and Theoretical Study on Air Purification and Vapor Recovery

Abstract

Pressure swing adsorption (PSA) air purification/vapor recovery was studied by experiments and model simulations using dimethyl methylphosphonate (DMMP) vapor and activated carbon. The most significant result was that complete cleanup of the product effluent resulted when starting from a saturated bed even for the very strongly adsorbed vapor, DMMP. Furthermore, at the same time, a concentrated DMMP vapor was produced at the exhaust effluent. Therefore, PSA cannot only be used to purify air, it can also concentrate the vapor for more efficient recovery or abatement. Also, two cyclic steady states were demonstrated both experimentally and theoretically. When starting from a clean bed, the concentration wave penetrated the bed very slowly while a cyclic steady state was being approached and much of the bed remained unused acting as a guard against product effluent contamination. However, when starting from a saturated bed, a different cyclic steady state was approached where a “heel” existed in the bed at the product effluent end. © 1991, American Chemical Society. All rights reserved.