Simultaneous optimal design and operation of a diabatic extractive distillation column based on exergy analysis

Abstract

The concept of diabatic distillation is applied to an extractive distillation system of ethanol, which uses glycerol as entrainer, to study the influence of heat flows in optimal design, operation, and thermodynamic efficiency of such systems via exergy analysis. First, optimal operating conditions for minimum exergy losses are computed for a diabatic column with fixed feed locations and number of trays. Then, optimal design (feed locations, number of trays, and heat flows along the column) and operation of the system is calculated as a mixed integer nonlinear programming (MINLP) problem, for an economic and economic-exergetic objective functions for two different entrainer molar flows. It was found that the entrainer molar flow has remarkable influence in the reduction of the exergy losses of the system.