Effect of acoustic field on CO2 desorption in a fluidized bed of fine activated carbon

Abstract

Adsorption using solid sorbents has the potential to complement or replace current absorption technology, because of its low energy requirements. Among the commercially available adsorbent materials, attention is focused on activated carbons because they are easily regenerable by reason of their low heat of adsorption. These sorbents are generally available in the form of fine powders. Sound-assisted fluidization can process large amounts of fine powders, promoting and enhancing CO2 capture on fine sorbents, because it maximizes gas–solid contact. Temperature swing adsorption (TSA), consisting of inducing sorbent regeneration and CO2 recovery by appropriate temperature increase and gas purge, is one of the most promising techniques. This study investigates the CO2 desorption process by TSA in a sound-assisted fluidized bed of fine activated carbon. Desorption tests were performed under ordinary and sound-assisted fluidization conditions to assess the capability of sound to promote and enhance the desorption efficiency in terms of CO2 recovery, CO2 purity, and desorption time. The results show that the application of sound results in higher desorption rates, CO2 recovery and purity. Regular and stable desorption profiles can be obtained under sound-assisted fluidization conditions. This stability makes it possible to successfully realize a cyclic adsorption/desorption process.