Study on CO ₂ Capture from Flue Gas Using Aqueous K ₂ CO ₃ under Waste Heat Recovery

K2CO3 solution can be used to absorb CO2 during the direct contact of flue gas and circulating water for waste heat recovery. To verify the feasibility, the performance of K2CO3 solution in absorbing CO2 from hot simulated flue gas was studied in a wetted wall column. The results indicate that at a lower solution temperature (50 °C), the absorption under high-temperature gas conditions was inferior to that under conventional gas conditions and decreased with increasing gas temperature. The absorption was improved at low water vapor content and high solution temperature (60–70 °C). The behavior of moisture is key to the absorption under high-temperature gas conditions. Absorption was enhanced during moisture evaporation but inhibited under abundant moisture condensation. The feasibility of using a K2CO3 solution to capture CO2 from high-temperature flue gas during the waste heat recovery process was validated.