CO2 mineral trapping: Modeling of calcium carbonate precipitation in a semi-batch reactor

Abstract

In the current paper, CaCO3 precipitation process via CO2 absorption into aqueous solution of Ca(OH)2 was investigated in a stirred semi-batch reactor. Mathematical model describing the precipitation process was developed by considering the absorption and reaction kinetics as well as hydrodynamic conditions in the system. The model allows to simulate the concentration profiles of reactive species (CO2, Ca2+, OH−, CaCO3, HCO3−, H+, CO32−) in the gas and liquid phase as well as to predict the rate of CaCO3 formation. The volumetric mass transfer coefficient, kLaCO2 characterizing CO2 transfer performance from gas phase into Ca(OH)2 solution as well as rate constant of the CaCO3 precipitation reaction, k51 were estimated based on the experimental data and the developed model. The CO2 mass transfer enhancement factor E due to chemical reaction was also estimated.