The effect of boric acid on the vapour liquid equilibrium of aqueous potassium carbonate

Aqueous potassium carbonate has seen renewed interest as a viable solvent for pre and post combustion carbon capture and storage. However, slow reaction kinetics may require the addition of a rate promoter such as boric acid to improve efficiency. The vapour liquid equilibrium of 30 weight percent potassium carbonate with 0, 3 and 5 weight percent boric acid was investigated at 50 and 70 °C using a dynamic inert gas stripping method. By estimating the boric acid reactions an Electrolyte-NRTL model was able to fit this data and literature results very closely.

► Effect of 3 and 5 wt% boric acid on VLE of CO2 over 30 wt% potassium carbonate.
► Boric acid chemistry thought to increase loading, and thus CO2 partial pressure.
► Simplified specialisation enabled simulation with E-NRTL model at 50 and 70 °C.