Abstract
Synthesis of an optimal (minimum-cost) heat exchanger network is very important from the viewpoint of energy saving and cost reduction, but it is difficult to solve these synthesis problems because there exist an extremely large number of possible stream combinations to be considered.
A practical method composing three stages [pre-analysis, generation of initial networks, and evolution] was developed to synthesize an optimal network by hand calculation. The problem table is adopted to determine the minimum utility requirement precisely, and to search necessary conditions of maximum heat recovery in the pre-analysis stage. A simple algorithm of initial network generation is developed to generate nearly optimal networks considering maximum heat recovery and optimal locations of heaters and coolers. Initial networks are improved by simple evolutionary rules based on stream-splitting to increase the heat duties of units and to vary the exchanger sizes in the evolution stage. The effectiveness of this method is demonstrated by solving the synthesis problems reported in previous works.
