The amine scrubbing process is noteworthy for being a well-understood and robust technology for carbon dioxide (CO2) capture. Despite being widely used, the process is energy-intensive and may significantly decrease the energy efficiency of a power plant. In any absorption-based CO2 capture unit, the solvent regeneration step is the main contributor to the high power consumption.
Currently, the most mature alternatives for amine-based solvents are ammonia (NH3) and potassium carbonate (K2CO3) based aqueous solutions. When combined, these solvents present high absorption capacity and, specially, lower energy requirement for solvent regeneration than the standard solvent for amine scrubbing. Furthermore, the use of other additives may enhance the performance of such mixed-salt solvent.
When using these solvents, CO2 is chemically absorbed in the liquid phase. For this reason, the calculation of phase equilibrium is not straightforward, as it also depends on the chemical reaction equilibrium. These calculations require information on the temperature dependence of chemical equilibrium constants and thermodynamic models able to represent electrolyte solutions. The latter, in turn, rely on high quality experimental data to determine the parameters of the models accurately.
In this sense, the goal of this project is to create a reliable data-basis for a thermodynamic model suitable for simulation of absorption and desorption of CO2 using a new solvent consisting of NH3, MDEA, K2CO3, and water. The obtained model will be used to carry out process simulations and assess the efficient of this solvent.