Entropy Minimization in Design of Extractive Distillation System with Internal Heat Exchangers

摘要

A methodology for entropy production minimization in design of extractive diabaticrndistillation systems is proposed. The feasibility of the design is obtained by thernboundary value method used by Doherty and coworkers, and the optimal design isrnattained using a genetic algorithm, this strategy allows determine the optimal heat loadrndistribution, and the flows and temperatures for hot and cold utilities. For optimalrndesign of diabatic distillation columns it was employed a multilevel strategy, the firstrnlevel solves the optimal adiabatic design and the second one determines the optimal heatrnload distribution in the sequential heat exchangers (SHE), in both levels the feasibilityrnof the designs is forced by a penalty in the objective function, it considers the separationrnfeasibility and the energy balance consistency. The ethanol dehydration by extractiverndistillation with ethylene glycol is assessed in order to show our optimal designrnprocedure and to compare the diabatic distillation process with the adiabatic one.rnResults show that this strategy allows to solve the problem, and that with SHE, thernentropy production can be reduced expressively: 14% for the recovery solvent columnrnand 16% for the extractive one, compared to the adiabatic columns.