Optimal Retrofit of a Multiplant Heat Exchanger Network with a Fair Benefit Allocation Plan

Abstract

A model-based procedure has recently been developed to address the benefit allocation issue among members of an interplant heat integration scheme in the spirit of co-operative game. Although satisfactory results were reported, their approach is only applicable to grass-root designs. In practical applications, the existing plants on an industrial park were usually built to meet the targeted market demands, which arose during different periods in the past and each must have already been equipped with a heat exchanger network (HEN) by the time when its construction was completed. Therefore, the aforementioned allocation problem is more likely to take place when a multiplant HEN retrofit project is called for to facilitate a further reduction in utility consumption. This paper presents three viable strategies to solve the more realistic revamp problems. Depending upon other requirements in practical applications, for example, safety concerns, spatial limits, operability, and so forth, these strategies are devised by introducing different levels of restrictions on the new and original matches, on repiping and reusing of existing units in the multiplant HEN, and on the installation of purchased new heat exchangers, coolers, and heaters. The actual financial benefits allocated to the participating members of the interplant heat integration scheme are then determined according to the corresponding Shapley values. A simple example is presented in this paper to illustrate the aforementioned HEN retrofit and saving distribution procedures.