Prediction of CO2 and H2S solubility in aqueous MDEA solutions using an extended Kent and Eisenberg model

Gas sweetening, the removal of acid gases (H2S and CO2) by absorption in aq. alkanolamine solns., is an important gas treatment operation. Methyldiethanolamine (MDEA) is widely employed for gas sweetening, because of its high absorption capacity and flexibility to meet process requirements. For process simulation or design, realistic predictions of acid gas solubilities in MDEA solns. are needed. In the context of flowsheet synthesis, design and optimization, a reliable model that is simple to use and reasonably accurate is required. This paper presents a new model for the prediction of solubilities of both H2S and CO2 in aq. MDEA solns. The model extends the Kent and Eisenberg (1976) model, which was developed for primary and secondary amines. Model predictions are validated against exptl. data for both single and mixed acid gas systems. The applicability of the model is further demonstrated by comparing flowsheet simulation results and plant data for com. units operating over a wide range of conditions. [on SciFinder(R)]