Heat Exchanger Network Synthesis Using Node-based Non-Structural Model With Enhanced Dynamics for Stream Matching

Node-based nonstructural models (NNMs) for heat exchanger network (HEN) synthesis realize flexibilities for stream matching across the entire ranges of process streams, as the concept of stages is not used. These models can also accelerate the efficiency of optimization algorithms. However, since nodes are considered to be in fixed positions, heat exchangers tend to crowd in the feed regions of the process streams during the later stages of optimization. This crowding hinders the generation of new heat exchangers in those areas, eventually interrupting the randomness of the NNM and impeding structural optimization. This paper proposes a mechanism for adding split groups within existing node groups in process streams to allow for freer generation of new stream matches and reduce exchanger clustering. The random walk algorithm with compulsive evolution (RWCE) is utilized for HEN optimization. The algorithm is particularly suitable because it can evolve only existing heat exchangers while also generating new ones independently. Examples from the literature are solved to illustrate the applicability of the proposed modifications to NNM and the results compare well with solutions reported in the literature