CO2 Capture by Adsorption Processes

Adsorption is a reliable process technology that has been in use since the 1960s for gas separation applications. Since the mid 90s, interest has grown around CO2 emissions abatement with adsorption being one of the first technologies considered. There has since been significant research and development on both the materials science, and engineering aspects of adsorption for CO2 capture. Adsorbents with extensive histories such as zeolites, activated carbons, and layered double hydroxides have experienced resurgences, and novel adsorbents such as metal–organic frameworks and microporous organic polymers were conceived. Adsorption-based separations are cyclic processes, and methods to improve the attainable purity and recovery of the CO2 have also been investigated; this work has shown that 90%mol recovery and 95%mol purity are possible for post-combustion capture. Work is also underway to improve the throughput of gas–solid contacting devices as a form of process intensification, which is required for high volumetric flow rate applications. Although there are still some concerns around the stability of some adsorbents to impurities, there have been meaningful and significant advancements over the last 20–25 years. These have made adsorption a viable technology for carbon capture applications.