Optimum solvent concentration to lower energy demands for CO2 capture in refinery cases

An open-access novel low-energy solvent HS-3 has been proposed and verified in the lab scale for post-combustion CO2 capture. The HS-3 solvent consists of a tertiary amine with a strong bicarbonate former and a primary amine with high reactivity. Blends of these two solvents have been reported to be promising solvent candidates. In this work, empirical density, viscosity, and thermal properties correlations together with the rigorous thermodynamic model were used to evaluate the energetic performance of individual solvent components and their blends. A simplified method mimicking the absorber and stripper conditions was used to evaluate the performance of the solvents. Blends of these two amines at five different ratios were evaluated and the results show better energy performance than MEA 30 mass%. Based on the evaluation done, the blend of 40 mass% of Amine 1 and 15 mass% Amine gives the lowest energy requirement (2.5 MJ/kg CO2). In addition, the viscosity increases with solvent concentration but the changes were considered not to be so significant.