High Efficency CO2 Separation and Concentration System by Using Molten Carbonate

Abstract

One of the most important problems of CO2 capture systems is that systems require significant amounts of electrical or thermal energy. In particular, it is difficult to collect CO2 from gases that contain low CO2 concentrations. Another problem is that exhaust gases have high temperatures. In addition, such gases contain many impurities and fly ash, such as carbon. Carbonate is indicated as MxCO3 in chemical formulae. From the viewpoint of elements of composition, CO2 occupies half the weight of this material. At high temperatures, this substance is used as an electrolyte in high temperature fuel cells. It can be used for electrochemical CO2 separation systems. In the case of Molten Carbonate Fuel Cells, this carbonate ion reacts with H2; it produces H2O and CO2 (1:1).These systems can separate 0.42 liters of CO2 from the cathode to the anode, per 1 A current per hour. These systems have high selectivity for CO2 in the gas. Carbon ash or other remaining fuel is burned and removed in the cell. The chapter also proves the availability of collection of CO2 using this system. The composition of the gas used was 67% CO2 and 33% O2; this ratio is equal to the chemical composition of the carbonate ion. By this cell test, it was confirmed that CO2 can be collected from the gas, even when present at less than 1% CO2. From these results, it is clear that this carbonate system is very suitable system for CO2 collection.