CO2 capture from flue gas by two successive VPSA units using 13XAPG

Abstract

With the development of novel adsorbent material and adsorption process, adsorption technology has become a potential tool for the CO2 removal from flue gases. The reduction of carbon dioxide emissions from flue gases with two successive vacuum pressure swing adsorption (VPSA) units, using 13XAPG as the adsorbent, was investigated both theoretically and experimentally. A 3-bed 5-step VPSA process was designed to capture CO2 from flue gases, which included feed pressurization, adsorption, rinse, blowdown and counter-current purge. It was found that was difficult to achieve both high CO2 purity and high CO2 recovery by one VPSA unit when capturing CO2 from flue gases at atmospheric pressure. After the verification of one-column VPSA experiment for further concentrating CO2 stream from one VPSA unit to above 95 % purity, two successive VPSA units were designed, composed of 3-bed 5-step cycle for the first unit and 2-bed 6-step cycle for the second unit, and the effects of operating parameters on the separation behaviors were investigated by simulation. With the proposed VPSA process, a CO2 purity of 96.54 % was obtained with recovery of 93.35 %. The total specific power consumption of the two successive VPSA units was $528.39\mbox{~kJ/kg}_{\mathrm{CO}_{2}}$ , while the unit productivity was $0.031\mbox{~kg}_{\mathrm{CO}_{2}}\mbox{/kg\,h}$ .