On improving the CO2 recovery efficiency of a conventional TSA process in a sound assisted fluidized bed by separating heating and purging

Abstract

Carbon capture from point source emissions has been recognized as one of several strategies necessary for mitigating release of greenhouse gases (GHGs) into the atmosphere. Though several CO2 capture technologies have been proposed, temperature swing adsorption (TSA), consisting in adsorbing the CO2 and, then, recovering it by a temperature increase and gas purge, is currently believed to be one of the most promising for post-combustion applications. With reference to the sorbent, great attention is focused on fine powders. Indeed, sorbent in the form of fine powders can be the substrate to realize new highly specific materials whose properties can be tuned at a molecular level and, besides that, most of the commercial adsorbent materials are generally available in the form of fine powders. Previous works successfully verified the feasibility of carrying out TSA adsorption/desorption cycles in a sound assisted fluidized bed, thus enhancing the performances of the entire cyclic process. The focus of the present work is to overcome the main drawback of a conventional TSA, namely the dilution of CO2 in the purging gas, by changing the traditional heating method. To this aim, a separate heating and purge regeneration strategy, consisting in desorbing part of the CO2 by the sole thermal effect, has been tested on a commercial activated carbon, thus eliminating the unavoidable dilution effect caused by purge, and the remainder reducing the CO2 partial pressure. Heating is very efficient for desorbing CO2. Indeed, 80% of the captured CO2 can be recovered at a moderate temperature of 130 °C.