Evaluation of dual-bed pressure swing adsorption for CO2 recovery from boiler exhaust gas

Dual-bed CO, adsorption using zeolite was studied experimentally and theoretically. Boiler exhaust gas (13 vol% CO2, 79 vol% N-2 and 8 vol% O-2) was used as a feed gas for the eight-step four-bed PSA process. Na-X type zeolite (NaX) and Na-A type zeolite (NaA) were selected in the break-through test. NaX has higher CO2 adsorption capacity than other adsorbents. NaA has the highest selectivity among all adsorbents tested. In the simulations, a NaX-to-NaA ratio affected the recovery efficiency and the concentration of recovery gas. Moreover, in the dual-bed PSA process of NaX-to-NaA ratio = 2/1, the recovery efficiency and CO2 concentration of recovery gas were higher than those in a sin.-le-adsorbent PSA process. Simulated results by the dynamic model agreed well with the PSA experimental results. (C) 2001 Elsevier Science B.V. All rights reserved.