Heat exchanger network retrofit in crude distillation unit

Abstract

For refineries throughout the world, energy management is an important element for controlling total operating costs. Over the past decades, there appears to be an urgent need to retrofit the existing Heat Exchanger Network (HEN) of Crude Distillation Units (CDU) to reduce the current utility consumption. In this paper two different retrofit methods to perform retrofit are compared: Pinch technology, and MILP method (Nguyen et al., 2010). To make the comparison even more fair, retrofit using Pinch Technology is improved by the incorporation of an optimization step is presented. From the comparison of the above two retrofit technologies; it was found that the pinch technology with optimization software is a powerful procedure to do HEN retrofit based on ease of use and systematic approach. However, the accuracy of pinch technology extremely depends on the selection of the best network from all possibilities. The limitations of the MILP model, even with the one-step computational procedure, cannot get the global optimum HEN retrofit design.