ENERGY MINIMIZATION IN PETLYUK DISTILLATION COLUMN

Abstract

Distillation is the most widely used industrial separation technology and distillation units are responsible for a significant part of the total heat consumption in the world's process industry. The reduction of energy consumption in distillation has become a need of the hour. In this work we focus on Petlyuk distillation column for separation of multicomponent mixtures. The general analytic solution has been derived for minimum energy consumption in Petlyuk distillation column for multicomponent mixtures and the derivation is based on Underwood's classical methods. The Vmin-diagram has been introduced as a useful tool for assessment of any multicomponent separation task. The total required energy consumption and the vapor load and separation carried out in all parts in a directly integrated column arrangement (i.e. Petlyuk Column) can be obtained by just a glance at the Vmin-diagram. Two extra degree of freedom can be used in Petlyuk distillation column for optimization purposes. The concept of self-optimizing control has been used for control structure design and in particular to propose that should be controlled to a set point and at the same time, this ensures close to optimal operation. We have studied the some performance of some self-optimizing control configurations for the Petlyuk column in the presence of disturbances and uncertainties. It has been calculated, energy saving of 36% is achieved for ternary mixture of methanol, isopropanol and n-propanol with a Petlyuk distillation column, as compared to conventional distillation arrangements.