Rate Based Distillation

Although the equilibrium model has been the basis of the simulation of distillation columns, its shortcomings are well known. The model is based on the assumption that both phases leaving a stage are in thermal and material equilibrium. In practice equilibrium is rarely attained since mass and heat transfer are actually rate processes that are driven by the gradients in chemical potential and temperature. The equilibrium models predicted results far from the practical and experience alongwith rules of thumb were used as a tool to bridge the gap, hence came the Rate based simulation into picture. There has been a lot of work into this field in the recent times as its potential has been explored by the researchers. The use of the rate based model eliminates the requirement for mass transfer coefficients, Murphree stage efficiencies, liquid holdups, residence time etc. All these are calculated by the simulation engine based on the real time performance.

The aim of the presentation will be to elaborate the differences between the two models and their comparison.