A rigorous rate-based model for reactive sour gas absorption by aqueous amine solutions is presented which governs both the coupling of mass transfer and reaction and specific features of electrolyte species. The acceleration of mass transfer due to reactions in the liquid phase is taken into account rigorously, without application of enhancement factors. The model is implemented into the simulation environment Aspen Custom Modeler and validated by comparison of published pilot plant data with the simulation results. It is shown, that the model possesses a good predictivity for pilot plant scale as well as for industrial scale applications. In addition, the influence of reaction kinetics on the absorber performance is studied. (C) 2003 Elsevier Ltd. All rights reserved.