Retrofit of Refinery Heat Exchanger Network under Different Kinds of Crude Oil by Pinch Design Method using Mathematical Programming

Abstract

Crude distillation units (CDUs) in refineries are major consumers of energy. Because of the high energy consumption of the crude furnace in the crude preheat train, heat integration by retrofitting the heat exchanger network (HEN) is presented in this research using a retrofit potential program and stage-model mathematical programming. The retrofit potential program from Kosol (2012) based on pinch technology was used to identify the optimum heat recovery approach temperature (HRAT). The n-stage model from Zamora and Grossman (1996), a mathematical programming using General Algebraic Modelling System (GAMS), was used to generate the retrofitted HEN with a minimum number of exchangers and maximum heat recovery at pinch exchangers match as an objective function. The simulation software (Pro/II) was used to validate designs and perform total utility consumption. An example of a CDU was simulated with light, medium and heavy crude oil feed for operating periods of 100, 150 and 100 days per year, respectively. The retrofit of the crude preheat train was applied to find the optimal and most profitable HEN design that yields the highest net present value (NPV).