Hydrogen Sulfide Solubility in Aqueous Solutions of MDEA, MEA, and DEA: Bridging Theory and Experiment with eCPA Equation of State

Gas treatment procedures play a crucial role in eliminating acidic gases from natural gas and other hydrocarbon streams. Within the confines of this investigation, we propose an innovative methodology that employs the eCPA equation of state to prognosticate the solubility of hydrogen sulfide (H2S) in aqueous solutions containing N-methyl diethanolamine (MDEA), monoethanolamine (MEA), and diethanolamine (DEA). The electrolyte Cubic Plus Association (eCPA) equation of state takes into account six vital parameters, encompassing the molecular size, configuration, and polarity of the constituents, to accurately anticipate the equilibrium treatment of H2S absorption in various conditions. The results acquired from the experimental assessment of H2S solubility were juxtaposed with those derived from modeling, revealing a commendable concordance amidst the respective data. In order to gauge the accuracy of the projected model, we employed the absolute average relative deviation (AARD%) as a statistical error-index. The experimental data procured in this study exhibited an acceptable validation in accordance with the outcomes of modeling endeavors. The performance evaluation reveals that, within the temperature range of 25-140 °C, acid gas loadings of 0-1.6 (mol gas/mol solution), and aqueous alkanolamine amounts of 15-49 wt. %, the absolute average relative deviation (AARD%) remains consistently below 4.5%. This emphasizes the reliability and efficiency of our model in accurately predicting H2S solubility under diverse operating conditions.