IMPLEMENTATION OF OPTIMAL OPERATION
FOR HEAT-INTEGRATED DISTILLATION COLUMNS

Hilde K. Engelien, Truls Larsson and Sigurd Skogestad

Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway

Presented at Distillation'2002 Symposium, Baden-Baden, Germany, Oct. 2002

Abstract

A multi-effect distillation where the condenser of a high pressure column is integrated with the reboiler of a low pressure column has been studied. The method of self-optimising control has been used to provide a systematic procedure for the selection of controlled variables, based on steady state economics. The heat integrated distillation system was optimised to find the nominal operating point and it was found that a temperature in the low pressure column has good self-optimizing properties. The study also shows how there can be multiplicities in the objective function for certain variables in the system.