Optimal allocation of cleanings in heat exchanger networks

This paper addresses the identification of the optimal set of heat exchangers to be cleaned during a plant maintenance shutdown. The proposed methodology is based on the resolution of a mixed-integer linear programming problem which allows the identification of the cleaning requirements aiming to reduce costs during the interval between scheduled plant shutdowns. The linear structure of the proposed formulation avoids problems associated to multiple local optima, and the resultant problem dimension allows the analysis of large heat exchanger networks without excessive computational efforts. The application of the proposed approach is illustrated through the investigation of two heat exchanger networks. The first example explores some typical cleaning patterns and the other example demonstrates the utilization of the proposed approach applied to a real network.