Abstract
HRL (heat recovery loop) is an indirect method for transferring heat from one plant to another plant using intermediate-fluid circles. Inter-plant heat integration using HRL is a very special approach for energy conservation, as there are some additional factors should be considered, such as the capital cost of additional heat exchangers, pumps and pipelines for long distance, operation cost of pumping power and heat loss during the transportation. Moreover, when the number of plants involved in Heat Integration is large, the connection between plants have to be considered. These factors simultaneously determine the possibility and performance of Heat Integration. In this work, graphical targeting and mathematical programming is combined, a generalized MINLP model with economic objection is proposed to minimize the total annual costs (TAC) for Inter-Plant Heat Integration using HRL. As this work concentrates on heat recovery in low temperature range, hot water is selected as the heat transfer medium. The solved results can give the mass flow rate of intermediate-fluids, diameter of pipeline, temperatures of the heat transfer medium and the configuration of heat exchanger networks (HENs). An industry case study with three plants is used to demonstrate the model.
