Calculation of phase equilibrium of alkanolamines systems with CPA equation of state based on Shield-Sticky model

Considering an association contribution,combining cubic P-R model with an association contribution,a new CPA (cubic-plus-association) equation of state (EoS) was presented in this paper.The association term was directly computed with association equation which was proposed based on the Shield-Sticky model(SSM).The new CPA-SSM EoS was then used for descriptions of phase behavior of pure alkanolamine fluids and their mixtures.New molecular parameters for 8 alkanolamines were obtained by fitting experimental saturated vapor pressures and liquid densities at reduced temperature range from 0.55 to 0.90.The overall average deviations of saturated vapor pressure and liquid density were only 0.57% and 1.80% respectively.Using an adjustable parameter independent temperature,satisfactory calculations for binary isothermal and isobaric vapor-liquid equilibria (VLE) were obtained.In addition,this model can successfully reproduce VLE of multi-component mixtures in virtue of binary information.