Improvement in Regeneration Properties and Multicycle Stability for K2CO3/Al2O3 Adsorbents for CO2 Removal from Flue Gas

A new adsorbent based on potassium carbonate (K2CO3) supported on modified gamma-Al2O3 has been developed in this work. It has shown excellent multicycle stability with adsorption and regeneration at 55 and 130 degrees C, respectively. The support (gamma-Al2O3) is stabilized by thermal treatment and alkali treatment with hydroxide, followed by calcination. The excellent regeneration characteristics are due to minimal interactions between the support and reactants during CO2 adsorption. This is due to acidity reduction of the support responsible for the formation of stable species, for example, KAl(CO3)(2)(OH)(2). Various physicochemical characteristics have been studied to understand the adsorption and regeneration behavior of the adsorbents over multiple cycles. The effects of operating parameters, such as adsorption temperature, thermal dehydration of support material, and gas hourly space velocity (GHSV), during regeneration have also been studied. The CO2 adsorption capacities are found to be in the range of 2.3-2.6 mmol of CO2/g of adsorbent (10-11.4 wt % CO2), which also shows good stability after multicycle tests. The developed adsorbents also show high attrition resistance and, thus, can be effectively used in commercial application for CO2 capture.