Rate-based simulation study of boric acid promoted potassium carbonate capture system

Abstract

This study presents parametric analysis and process modification on a post-combustion carbon dioxide (CO2) capture system using boric acid promoted potassium carbonate (K2CO3) solution. The model was simulated in Aspen Plus® V10 and ELECNRTL property package was employed. Un-promoted K2CO3 system was adopted as a base case study and its simulation was validated using literature data. The K2CO3 concentration in the lean solvent makeup was then varied from 25 wt% to 40 wt% to examine the effects of lean solvent concentration on key operating variables such as stripper reboiler duty, stripper condenser duty and CO2 capture rate. A 2 wt%, 4 wt% and 6 wt% aqueous boric acid solutions were then added as promoter to the hot K2CO3 solvent and the simulation results indicated that capture rate efficiency can be enhanced by 0.7%, 0.9% and 1.2% respectively. Energy saving process modification was also carried out to the stripper column. Compared to the conventional unmodified H3BO3/K2CO3 system, the modified promoted system is able to achieve 21.09% savings in reboiler duty.