Alternative regeneration of chemicals employed in mineral carbonation towards technology cost reduction

This work investigates the feasibility of a liquid-liquid extraction technique to replace the energy intensive salts/water separation step. Also, the CO2-balance of a 500 MW coal-fired based power plant with an integrated pH swing MC facility was investigated. Different operating conditions were investigated, including temperature, reaction time, pressure, solid to liquid ratio (S/L), reagents concentration and stirring rate. An ammonium sulphate/water separation higher than 90% was achieved at 25 °C, 10 min, 1 bar, 200 g/l S/L ratio, 70% methanol and, 350 rpm. The associated energy consumption was calculated, resulting in an energy saving of 35% in comparison to water evaporation. The process resulted carbon negative when water evaporation was replaced by extraction technique, with 33% of CO2 sequestered by using a S/L ratios of 300 g/l.