Game-theory based optimization strategies for stepwise development of indirect interplant heat integration plans

Since the conventional design strategies for interplant heat integration usually focused upon minimization of the overall utility cost, the optimal solutions may not be implementable due to the additional need to distribute the financial benefits “fairly.” To resolve this profit sharing issue, a Nash-equilibrium constrained optimization strategy has already been developed to sequentially synthesize heat exchanger networks (HENs) that facilitate direct heat transfers across plant boundaries. Although this available approach is thermodynamically viable, the resulting network may be highly coupled and therefore inoperable. To address the operability issues in any multi-plant HEN, the present study aims to modify the aforementioned strategy by considering only indirect interplant heat-exchange options. Two separate sets of mathematical programming models are developed in this work for generating the total-site heat integration schemes with the available utilities and an extra intermediate fluid, respectively. The negotiation powers of the participating plants are also considered for reasonably distributing the utility cost savings and also shouldering the capital cost hikes. Finally, extensive case studies are presented to demonstrate the effectiveness of the proposed procedures and to compare the pros and cons of these two indirect heat-exchange alternatives.