Vacuum swing CO2 adsorption cycles in Waste-to-Energy plants

Abstract The performance of vacuum swing adsorption-based processes applied to CO2 capture in Waste-to-Energy plants is explored for the first time. CO2 capture and storage (CCS) are gaining increasing attention in this sector. The analysis of simple cycle configurations for this particular application provides a reference scenario to explore the potentiality of the adsorption technology. Under these premises, the objective of this study is to maximize the CO2 separation from the flue gas of a solid waste incineration facility. Three vacuum swing adsorption (VSA) and one vacuum and temperature swing adsorption (VTSA) configurations were assessed in a fixed-bed laboratory unit and the influence of the cycle design, the number of columns and the operational conditions were analyzed. The adsorbent employed is an activated carbon produced from pine sawdust, a forestry by-product with great availability in our region. Mathematical modeling developed in Aspen Adsorption complemented the experimental study which in turn validated the created model. Additional simulations were performed to further evaluate the effect that the different vacuum swing adsorption configurations have on product purity and recovery. With relatively simple configurations consisting of a maximum of 4-beds, CO2 recoveries above 95% were achieved and CO2 purity was increased from 8% to approximately 35-40%.