The solubility calculation of methane and acidic gases in associating solvents by a predictive approach using Henry’s law together with SRK and CPA equation of states

Abstract

In this study, the binary interaction parameters (BIPs) between a solute and solvent were calculated by combining Henry’s law and an equation of state (EoS) while the obtained BIPs were then applied to predict the solubility of carbon dioxide, hydrogen sulfide, and methane in various associating solvents. Water-CO2, water-H2S, water-CH4, methanol-CO2, methanol-H2S, methanol-CH4, ethanol-CO2, 1,2-propanediol-CO2, and glycerol-CO2 mixtures, were studied by Soave-Redlich-Kwong (SRK) and cubic-plus-association (CPA) EoSs over a wide range of temperature and pressure (a total of 384 data points). Both EoSs were capable of predicting the solubility of gases in studied associating solvents by obtained BIPs at investigated temperatures and pressures; however, CPA EoS has produced relatively more satisfactory results with a general absolute average relative deviation (AARD) of 5.38% compared to SRK EoS with that of 6.21%. This can be atributed to the high potential of CPA EoS in describing associating compounds (water and alcohols). Moreover, there was a linear relationship between obtained BIPs and temperature for some mixtures, while for others a quadratic one was the best.