Direct heat exchanger network synthesis for batch process with cost targets

A new method dealing with the synthesis problem of heat directly exchanged network (HDEN) for batch process based on pseudo-T–H diagram approach (PTHDA) is presented in this paper. A nonlinear programming (NLP) model targeting minimal annual total cost of network is formulated, with which operation cost for utilities as well as capital cost for heat exchanger units can be minimized simultaneously. Meanwhile, the heat exchanger network (HEN) structure which is seldom considered in a batch process can also be constructed. To be more practical and economic, the ways of identifying common units and the elimination of unnecessary heat exchangers are discussed and the global optimal solution is obtained with a parallelized genetic–simulated annealing algorithm (GA–SA) developed by our group. Finally, an example is used to show the application and effectiveness of the proposed method.

► Direct HEN for batch process without medium storage or changing original flow-sheet. ► PTHDA is firstly used in the batch heat directly exchanged network synthesis problem. ► The use of common units is especially introduced in the method.