Thermodynamics of thermally-driven adsorption compression

•Rachford-Rice equation system is extended to adsorption.•The application to ideal and non-ideal cases is shown.•The common tangent plane is used to test thermodynamic consistency.•The procedure allows the study of solid compressors.

Adsorption compressors are an emerging technology used to compress a gas stream with low grade heat which is of interest for the next long term extra-planetary bases. An analysis of thermodynamics of multicomponent gas/vapour mixtures compression with a thermally-driven adsorption bed is reported. In this unit a multicomponent stream is firstly adsorbed and secondly compressed by heating a bed at closed volume. The analysis is based on adsorbed solution theory applied to closed vessels where the composition and pressure of the bulk gas phase depends on temperature and volume of the whole system, leading to an isochoric-isothermal flash problem. Analysis of both an ideal and non-ideal adsorption compressor shows that the ideal approach is conservative, resulting in lower compression ratios at higher energy consumption.