Experimental and simulation study of CO2 and H2S solubility in propylene carbonate, imidazolium-based ionic liquids and their mixtures

Publication date: Available online 4 December 2019Source: The Journal of Chemical ThermodynamicsAuthor(s): Zhijun Zhao, Ying Huang, Zhaohuan Zhang, Weiyang Fei, Mingsheng Luo, Yongsheng ZhaoAbstractCurrently, solvent-based absorption is known as an effective technology to capture acid gases,e.g., CO2 or H2S. In this work, the constant-volume method is used to determine CO2 and H2S solubility in propylene carbonate (PC), imidazolium-based ionic liquids (ILs): 1-butyl-3-methylimidazolium tetrafluoroborate [Bmim][BF4], 1-hexyl-3-methylimidazolium tetrafluoroborate [Hmim][BF4], and 1-octyl-3-methylimidazolium tetrafluoroborate [Omim][BF4], and their mixtures at temperature from 303.15 to 333.15 K under pressures up to about 1 MPa. Besides, the quantum chemistry-based COSMO-RS models are used to predict the vapor pressure and the solubility in these solvents. The experimental results illustrate that adding [Omim][BF4] into PC can improve the CO2 and H2S solubility and the H2S/CO2 selectivity compared with the pure PC, which increases with the increasing [Omim][BF4] mass fraction in the mixtures. The simulation with COSMO-RS shows the vapor pressures of PC in the mixtures decreases with the increasing [Omim][BF4] mass fraction. Moreover, the prediction results show that COSMO-RS-Lei model is in much better agreement than COSMO-RS (ADF 2005) for predicting both CO2 and H2S solubility and the prediction accuracy of CO2 is better than that of H2S. Finally, the mixtures of PC and [Omim...

Source: The Journal of Chemical Thermodynamics - December 4, 2019 Category: Chemistry Source Type: research