Extractive distillation modeling of the ternary system 2-methoxy-2-methylpropane-methanol-butan-1-ol

Abstract

AbstractInfluence of model complexity on the separation equipment performance was investigated. As an example, separation of azeotrope formed by 2-methoxy-2-methylpropane and methanol was considered using butan-1-ol as an extractive solvent. Non-equilibrium model of a column for extractive distillation accounting for the mass and heat transfer rates was composed according to the rigorous Maxwell-Stefan theory. An empirical AICHE correlation was adopted for the calculation of binary mass transfer coefficients at column trays. Results of the column steady-state operation were compared with those obtained assuming different equilibrium models. Effect of the quality of the vapor-liquid equilibrium (VLE) description on the results of the separation simulation considering real behavior of either liquid or both equilibrium phases was tested. Real behavior of the liquid phase was computed according to the NRTL equation taking into account binary and, in some cases, also ternary equilibrium data. In case of real behavior of the vapor phase, the equation of state in the form of virial expansion was employed. Qualitative agreement was found comparing the simulation results calculated by equilibrium and non-equilibrium models of the extractive distillation column while using the same description of ternary VLE.