In petrochemical industry

operating conditions of heat exchanger networks(HEN) are always changed

which particularly fouling-induced heat resistance keeps increasing over time. To overcome variation of operating conditions

several optimizing methods on design and retrofit of multi-period HENs are available with no consideration of fouling effect on HEN. The inevitable HEN fouling and increase of heat resistance will drive operation deviate from optimum value and make it difficult to sustain energy saving. A synthesis design method of multi-period HENs based on continuous energy saving was proposed which optimal synthesis was achieved by targeting total accumulative cost and considering fouling influence. First

case study to analyze fouling influence on multi-period HENs showed that optimal value of multi-period HEN in each period had been changed due to fouling. Then

a model on optimizing multi-period HEN was established by considering continuous energy saving and objective function of total accumulative cost. Finally

case study indicated effectiveness of the design optimization method.