The optimization of heat exchanger networks(HEN)is a typical MINLP problem.For large-scale HEN,when the number of process streams increases,its feasible configurations could increase exponentially.Till now,no effective methods are available to solve such problems.A new strategy based on the optimization of the sub-networks of HEN was proposed.According to the first optimization,the sub-networks underwent recombination,decomposition and transplantation operations were further optimized with the hybrid genetic algorithm.Evolution of the sub-networks instead of the optimization of the whole HEN was simple and fast.A large-scale HEN with 22 hot and 17 cold streams from literature was calculated with this new method and a better result was obtained.Although the exchanger area increased a little,the number of heat exchanger units was less,also utility and total annual cost decreased.
