Excellent thermal stability of potassium-based sorbent using ZrO2 for post combustion CO2 capture

Effects of calcination temperature and atmosphere on the CO2 sorption and regeneration characteristics of potassium-based sorbents using ZrO2 or TiO2 as supports were investigated in a fixed bed reactor in a temperature range 60–150 °C. We found in this study that potassium-based sorbents using ZrO2 showed excellent CO2 capture capacity regardless of calcination temperature and atmosphere. This is due to the fact that the potassium-based ZrO2 sorbents form only K2CO3 and ZrO2 phases without any new alloy species, whereas the inactive K–Ti alloy species such as K2Ti2O5 and K2Ti6O13 are formed during calcination for potassium-based sorbents using TiO2. From these results, we conclude that the thermal stability of the sorbents can be improved by using ZrO2 as a support instead of TiO2.