Optimization model for structural modifications in the retrofit of heat exchanger networks

Abstract: This paper presents a systematic procedure for performing the fewest structural modifications in the retrofit of existing heat exchanger networks. An MILP assignment- transshipment model is proposed which has as objective to minimize first, matches that require new units and then matches that require reassignment of existing units. The special structure of this problem implies that its computational effort is similar to the MILP transshipment model for grassroots networks. The application of the proposed model is illustrated with two example problems.