Performance of a parallel passage adsorbent contactor

Abstract

Results of an experimental and theoretical study of a parallel passage adsorbent contactor are reported. Theoretical considerations suggest that such an adsorber should be preferable to the traditional packed bed for applications in which pressure drop is important. An expression for the HETP (height equivalent to a theoretical plate) for a parallel passage contactor, analogous to the van Deemter equation for the packed bed, is derived and verified experimentally for the adsorption of several light gases from a helium carrier in an adsorber consisting of parallel sheets of activated carbon fibre adsorbent. The extension to a multiple passage system and the effect of moisture in the feed gas were also investigated. A high selectivity ratio ($\text{αCO}{}_2\text{N}{}_2$) and a diffusion time constant of about 10 ms for adsorption of CO₂ and N₂ on activated carbon fibre (ACF) adsorbent confirm that such a parallelsided duct coated with ACF sheets would be well suited to a dual piston rapid pressure swing adsorption system for large throughput and low value added applications such as CO₂ removal from stack gas.