Ali Haghtalab - Chemical Engineering Department, Qatar University
Mohammad Dehghani Tafti - Chemical Engineering Department, Tarbiat Modarres University

Thermodynamic modeling of solubility of acid gases in aqueous alkanolamine solutions is essential in design of an absorber for sweetening of natural gas. A thermodynamic consistent model was developed for calculation vapor-liquid equilibria in acid gases (H2S & CO2)-alkanolamine-water system. This model accounts for both chemical and phase equilibria in liquid and vapor phases. For nonideality of species in liquid phase the UNIQUAC-NRF equation with ion-pair approach was applied. For long range interaction the Pitzer-Debye-Huckel term was used. The model applied for correlating and prediction of the solubility of acid gases in binary aqueous solutions of MEA and AMP. The results obtained by this model are in very good agreement with experimental data.