Carbon dioxide absorption mechanisms of sodium added to calcium oxide at high temperatures

To apply the CO2 absorber at about 1000 °C for integrated coal gasification combined cycle (IGCC) furnace, the reactions of calcium oxide and CO2 at high temperatures was examined. Calcium carbonate reacts with sodium hydrogen carbonate below 200 °C and forms sodium–calcium complex carbonate. The sodium–calcium complex carbonate melts at 813 °C, and the carbon dioxide absorption and discharge reversible reactions of calcium-oxide takes place via liquid at around 1000 °C. Sintering of calcium oxide at high temperature has been successfully avoided by the addition of sodium.