Impact of mass transfer coefficient correlations on prediction of reactive distillation column behaviour

A significant part of the safety analysis of a reactive distillation column is the identification of multiple steady states and their stability. A reliable prediction of multiple steady states in a reactive distillation column is influenced by the selection of an adequate mathematical model. For modelling reactive distillation columns, equilibrium (EQ) and nonequilibrium (NEQ) models are available in the literature. The accuracy of the nonequilibrium stage model seems to be limited mainly by the accuracy of the correlations used to estimate the mass transfer coefficient and interfacial area. The binary mass transfer coefficients obtained from empirical correlations are functions of the tray design and layout, or of the packing type and size, as well as of the operational conditions and physical properties of the vapour and liquid mixtures. In this contribution, the nonequilibrium model was used for the simulation of a reactive distillation column. For prediction of the binary mass transfer coefficient for a sieve tray, four correlations were chosen to showtheir impact on the prediction of the reactive distillation column behaviour. As a model reactive distillation system, the synthesis of methyl tertiary-butyl ether (MTBE) was chosen. The steady-state analysis and the dynamic simulation of the model system were done. Qualitative differences between the steady states were predicted using the chosen correlations.