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.