Rigorous heat exchanger networks synthesis using a hybrid method

This paper presents a hybrid method for heat exchanger networks synthesis including the detailed design of heat exchangers. This task is achieved by combining the heuristic rules of the pinch analysis with a mathematical programming technique, together with an optimal design algorithm of shell and tube heat exchangers based on the rigorous Bell-Delaware method, In this way, the stream pressure drops are treated as optimization variables. As a result, the capital cost of pumps and the electricity cost to run these equipments are considered in this synthesis problem together with the costs for heat exchanger area and utility consumption. Therefore, the major contribution of this method is in addressing properly the stream pressure drops effects on the total annual cost of a heat exchanger network. Furthermore, the method avoids the solution of complex MINLP models and consequently it can be applied to solve large problems. The efficacy of the proposed method is demonstrated by solving two published problems, for which the total costs of the solutions resulting from the present method are as much as 72.42% lower than those of the published solutions.