Retrofit design of an energy integrated distillation system

Abstract

This work presents the retrofit design of an industrial N, N-dimethylformamid (DMF)-water separation system originally consisting of three heat-integrated distillation columns. Our task was to examine how the capacity of the separation system could be increased by 42.8%. If necessary an unused on-site extra distillation column was available for the project. The performance of the existing distillation system and of various increased-capacity structures have been studied using rigorous process simulation. Our study shows that the required capacity increase can be attained by adding the extra distillation column only when replacing the column internals of the original columns and when installing a new structured packing also into the available extra column. Replacing the column internals is expected to result in better controllability, too.