Ca2CuO3: A high temperature CO2 sorbent with rapid regeneration kinetics

Three different calcium-based ternary oxide sorbents, Ca2CuO3, Ca3Co4O9, and Ca2Fe2O5, were characterized as potential sorbents for CO2 capture. The behaviors of these sorbents were compared to CaO under various CO2 concentrations via temperature programmed carbonation/decarbonation. Ca2CuO3 and Ca3Co4O9 showed lower inversion temperatures, while Ca2Fe2O5 had a higher inversion temperature than CaO. In addition, the copper and cobalt containing sorbents showed relatively narrower temperature windows going from the highest carbonation rate to the highest decarbonation rate. This narrow temperature window can be advantageous in operating a temperature swing process. Ca3Co4O9 and Ca2Fe2O5 showed low conversion. Under the best-case scenario, the conversion of these sorbents was less than 25%. Ca2CuO3 showed faster regeneration compared to CaO when the sorbent temperature was cycled between 700 and 800 degrees C. In addition, we found 740-850 degrees C for Ca2CuO3 and 640-900 degrees C for CaO as the temperature swing windows of the best reaction rates. The narrower range of operational temperature (110 degrees C for Ca2CuO3 compared to 260 degrees C for CaO) can lead to higher overall rate of CO2 uptake and release. Ca2CuO3 showed 60% higher cycle-averaged decarbonation rate compared to CaO when cycled between the temperatures of maximum carbonation and decarbonation rates

Automated summary

Three different calcium-based ternary oxide sorbents were characterized and compared with CaO for CO2 capture. Ca2CuO3 showed faster regeneration and a narrower operational temperature range, indicating its potential as a better CO2 sorbent.