Effect of the operating parameters on the CO2 capture capacity of potassium carbonate supported on gamma alumina (K2CO3/γ-Al2O3) using conventional heat regeneration

Abstract

Potassium carbonate supported on gamma-alumina, which was prepared by impregnation and employed to adsorb carbon dioxide (CO2) under a turbulent fluidized bed regime, could be regenerated by heat treatment. The regeneration temperature and time were varied in the range of 200–300°C and 2–20min, respectively. Both parameters had a positive influence on the CO2 adsorption capacity in the subsequent adsorption cycle, while regression analysis showed an interaction between both operating parameters. At a low or high regeneration temperature, increasing the regeneration time reduced the subsequent CO2 adsorption capacity, which was explained by the thermal mass decomposition of sorbent with the major loss of surface water and inter-structural water at 100°C and 200–400°C, respectively. Based on the intensity of energy used in the different heat regeneration protocols, the operating parameters were optimized. Regeneration at 300°C for 20min led to a subsequent CO2 adsorption capacity of 90.7% of the fresh sorbent, but that at 200°C for 2min gave a CO2 adsorption capacity of 57.2% for a 1.8-fold lower regeneration energy.