An electrolyte segmental wilson-nonrandom excess Gibbs energy model and measurement of carbon dioxide solubility into sulfolane plus water and N-methyldiethanolamine plus sulfolane plus water systems

摘要

Removal of acid gases such as CO2 and H2S from natural gas and CO2 capturing are among the major steps in the gas industry which also effect the environment. Over decades, alkanolamines have been widely used for gas sweetening processes; however, along with the chemical solvent, a physical solvent has often been used to intensify the kinetics absorption of carbon dioxide. In this work, we obtained new experimental vapor-liquid equilibrium data for CO2 solubility in two systems of sulfolane + water and MDEA + sulfolane + water. In addition, an electrolyte segmental model, named eSegmental Wilson-Nonrandom (eS-Wilson-NRF), was developed and used for modeling the vapor-liquid equilibrium of the present systems. The model consists of two terms: the first term contributes the long-range interaction through the Pitzer-Debye-Hfickel theory, while for the short-range interaction, a segmental Wilson local composition was developed. For the sulfolane aqueous system, the gas solubility measurements were carried out at the sulfolane compositions of 10 and 20 wt % and temperatures of 328.15 and 393.15 K, as well as the CO2 partial pressure range of 189-3666 kPa. Further, the gas solubility measurements were performed using the systems of sulfolane + MDEA + water with the compositions of (10-40-50 wt%), (20-30-50 wt%) and (20-40-40 wt%) within the temperature range of 328.15-393.15 K and the CO2 partial pressures of 45-3593 kPa. Using eS-Wilson-NRF model, the results of the average absolute deviations percent (AAD%) for the sulfolane + H2O + CO2 and the sulfolane + MDEA + H2O + CO2 systems were 5.16 and 14.69, respectively. (C) 2019 Elsevier B.V. All rights reserved.