Real Acid Natural Gas Solubility Measurement in Novel Hybrid Solvents of Amine and Ionic Liquids

This study aims to investigate the performance of various hybrid solvents of amine and ionic liquids in the acid gas sweetening process. Two ionic liquids including [Hmim][NO3] and [Bmim][Ac] were used with MDEA amine solvent to investigate the solubility of H2S, CO2, and various hydrocarbons from a real natural gas. The solubility data were measured at a pressure range of 2~44 bar, temperature range of 298.15, to 338.15K, and ILs loading of 10~20(wt.%) in the hybrid solvents. The experimental design was employed to obtain the optimum condition of hybrid solvents. The results show that increasing ILs loading up to 10% in the hybrid solvent increased the CO2 solubility for both ILs up to 8.6%, and reduced the H2S solubility by up to 6% at the highest pressure and lowest temperature tested. The effect of pressure is the dominating factor on the solubility of the acid gases while the temperature and ILs loading percentage play a major role on the solubility of acid gases. In addition, the hybrid solvent containing 10 (wt.%) of [Bmim][Ac] showed better solubility towards CO2 in comparison to the solvents containing [Hmim][NO3]. It was concluded that this hybrid solvent is more suitable for CO2 absorption from natural gases containing higher CO2 and lower H2S concentration.