Determination of multicomponent mass transport processes for adsorptive environmental applications

Introduction The study of the kinetics of the competitive adsorption of multicomponent gas mixtures on solid adsorbents is important for a range of practical adsorption processes. One such environmental application is carbon capture and storage (CCS) [1], which includes the use of geological CO2 storage methods as well as the pre-combustion capture of carbon dioxide from syngas and post-combustion separation from flue gases [1-3]. The former include the storage of carbon dioxide in depleted oil and gas reservoirs and coal seams, while the latter use any one of a number of methods, including adsorption, to separate gaseous carbon dioxide from multicomponent gas flows. A range of porous materials are known to preferentially adsorb carbon dioxide over other species. These include activated carbons, zeolites and metal organic frameworks (MOFs), and these materials are therefore being considered for use in CCS technology [3]. The equilibria and kinetics of multicomponent adsorption from a number of different mixtures, including CO2/CH4, CO2/H2 and CO2/N2, are of fundamental importance to CCS technology, because the binary combinations mentioned above effectively represent a range of practical pre- and post-combustion gas streams. However, the experimental determination of the kinetics of multicomponent adsorption, in particular, is practically challenging.