Multi-objective optimization of multi-period interplant heat integration using steam system

Abstract

This paper proposed a mathematical model for formulating interplant heat exchanger network (HEN) operated under multi-periods. Each individual plant is linked through a centralized utility system and steam is selected as the heat transferring medium. Previous studies on optimizing interplant HENs mainly focus on minimizing the cost of system. In this study, the interplant HEN is optimized with two objectives: minimizing the cost and the environmental impact (EI). The maximum representative approach for the area of exchangers is used to formulate a flexible network that can be operated under the worst condition. A case study is employed to show the effectiveness of the proposed model. Pareto curves are plotted to exhibit the trade-off between the two different objectives. The results show that the utility system occupies a major part of the overall environmental impact, and the construction of exchangers does not exert significant impact on environments. Intensifying the heat integration by increasing heat exchanger areas is an effective approach for reducing environmental impacts of HENs, although it is not cost saving.