A systematic analysis of the dynamics of microwave- and conventionally-assisted swing adsorption on zeolite 13X and an activated carbon under post-combustion carbon capture conditions

This work presents a detailed parametric experimental work on the feasibility of microwave regeneration of two commercial adsorbents in a dynamic carbon capture swing adsorption system. A synthetic flue gas (15% v/v CO2 in N2) dry or with 15% relative humidity was selected, along with Norit R2020CO2 activated carbon and zeolite 13X. A purpose-modified experimental apparatus was used to compare microwave-assisted and conventional thermal swing regeneration. The impact of operating parameters on the dynamic process performance was measured for microwave and conventional heating. Parameters considered were type of adsorbent, flue gas composition, quantity of adsorbent (and bed size), and time of full regeneration, on CO2 capture capacity, recovery, purity and desorption kinetics. Results showed that microwave-assisted regeneration presents advantages over its conventional equivalent, as CO2 purity, recovery, and productivity were found to be higher under the former for the two adsorbents studied. For the time needed to achieve 50, 80, 90, and 99% regeneration, the benefits of microwave regeneration over conductive regeneration increased with an increase in sample size. Under the wet gas feed, Norit R2020CO2 and zeolite 13X showed an appreciably higher working capacity with microwave regeneration than with conventional regeneration (39.68 and 24.23% higher, respectively). Under the dry gas feed, the two adsorbents also maintained a higher working capacity with microwave heating as opposed to conductive heating (9.36 and 20.39% higher, respectively). The larger working capacity observed with microwave-assisted regeneration is attributed to the better regeneration.