Vapor–liquid equilibrium measurement and ENRTL modeling of CO2 absorption in aqueous hexamethylenediamine

• Vapor–liquid equilibrium of CO2 in aqueous Hexamethylenediamine is studied.
• CO2 solubility data is correlated using Electrolyte Non-Random Two Liquid (ENRTL) Model.
• Interaction parameters of the model are regressed using data regression system in Aspen Plus ((V7.3).
• Developed ENRTL model is used to predict liquid phase speciation, pH, Heat of absorption for (H2O + HMDA + CO2) system.

In this work, a new experimental data of CO2 solubility in aqueous solution of Hexamethylenediamine (HMDA) have been generated at 30, 40, 50 and 60 °C in the CO2 partial pressure range of 1–100 kPa. Concentration of aqueous HMDA used for solubility measurement ranges from 10 to 30 mass%. Electrolyte Non-Random Two Liquid (ENRTL) theory is used to correlate and predict vapor–liquid equilibrium (VLE) data. Model predicted data show good agreement with the experimental VLE data with an average absolute deviation of 11.0%. The ENRTL parameters are regressed from the experimental data of CO2 solubility using the data regression system (DRS) of Aspen Plus® (V 7.3). The ENRTL model is also used to predict equilibrium liquid phase speciation, solvent capacity, pH of the solution and heat of absorption of CO2 in aqueous HMDA solution.