The capture and storage of carbon dioxide from combustion flue gases is now recognized by government and industry as a viable near-term option for greenhouse gas abatement. Vapour–liquid-equilibria(VLE) models of CO₂–amine–H₂O systems are critical to understand the behaviour of these systems as a function of composition and temperature. A new vapour–liquid-equilibria models of CO₂–amine–H₂O systems is developed for exhibiting the behavior of CO₂ in aqueous solutions of methyldiethanolamine(MDEA). VLE models consist of chemical reactions and an activity model to describe non-ideal chemical behaviour at high ionic strength. The Simplified Kent-Eisenberg Model with only one equilibrium constant is employed to represent the nonlinear chemical equilibrium relationship in the solution, which reduces the number of model variables from 7 in the Kent-Eisenberg Model to 4. The Peng-Robinson equations of state with no binary parameter is used to calculate the fugacity coefficient in high pressure in the vapor phase. The liquid phase is treated as an electrolyte solution and activity coefficients are represented by the electrolyte–UNIQUAC mode. Adjustable parameters of the electrolyte–UNIQUAC mode, representing short range interactions, are determined by orthogonal distance regression technique using a large and wide range of experimental VLE data. The model predictions are in excellent agreement with the experimental measurements and commercial software HYSYS results are useful to be used in mass transfer models to represent the CO₂ absorption process using MDEA solutions.

Compare the bubble point temperature calculated in the paper with Aspen Hysys. Composition of liquid are MDEA:H<sub>2</sub>O:CO<sub>2</sub>=0.9375:0.0615:0.001 in molar percentage, pressure range from 1KPa to 1000KPa.

Compare the bubble point temperature calculated in the paper with Aspen Hysys. Composition of liquid are MDEA:H₂O:CO₂=0.9375:0.0615:0.001 in molar percentage, pressure range from 1KPa to 1000KPa.

Mr guo lianghui

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