Experimental Validation of Carbon Capture in Molten Salts at Low CO2 Concentrations (1-5 Vol%)

Carbon Capture in Molten Salts (CCMS) is a post-combustion carbon dioxide (CO2) capture technology, based on the reversible reaction between calcium oxide (CaO) and CO2 to form calcium carbonate (CaCO3). In CCMS, CaO and CaCO3 are dissolved (or partially dissolved) in a molten salt and thermally cycled between absorption (700°C, 0.1MPa) and desorption (950°C, 0.1MPa) conditions. In this work, CO2 absorption/desorption cycles using a eutectic calcium chloride / fluoride salt (86.2/13.8 wt% CaCl2/CaF2) with 10 wt% CaO has been demonstrated for low CO2 concentrations (1 – 5 vol%). The results show that CCMS can capture CO2 at all concentrations tested and the measured equilibrium conversion of CaO decreased with decreasing CO2 concentration, as expected. For the experiments with 1 vol% and 5 vol% CO2 the achieved conversion of CaO was found to be XCaO = 0.32 and XCaO = 0.50, respectively.