Co₂ solubility in electrolyte solution of potassium carbonate with the addition of promotor amines (MDEA-DEA/ PZ-DEA) at various temperatures

Carbon dioxide has a huge impact on the increase of greenhouse gas formation causing global warming and climate change. The most effective method to capture CO₂ is chemical absorption using potassium carbonate (K₂CO₃) solution and amines as additive to enhance the absorption rate. CO₂ solubilities in 30% of K₂CO₃ and 5% of the total composition of mixed methyldiethanolamine (MDEA)–diethanolamine (DEA)/piperazine (PZ)-DEA solutions at various temperatures of 303.15-323.15 K and atmospheric pressure are reported. The solubility data were measured using an equilibrium cell apparatus with the N2O analogy method. The E-NRTL model was used to correlate the experimental data accurately. The binary interaction parameters of the model for the CO₂-K₂CO₃-MDEA-DEA-H₂O and CO₂-K₂CO₃-PZ-DEA-H₂O systems were obtained. The CO₂physical solubility in 30% of K₂CO₃, 5% of PZ, and 0% of DEA at 303.15 K had the highest value, while the Henry constant of CO₂ in this solution had the lowest value. The CO₂loading increased with increasing partial pressure of CO₂, while the CO2 solubility decreased with increasing temperature. Any increase in MDEA concentration from 0% to 5% enhanced the CO₂ partial pressure, otherwise, an increase in PZ concentration from 0% to 5% decreased the CO₂ partial pressure.