Heat exchanger network synthesis with detailed design: Reformulation as a shortest path problem by temperature discretization

Thesis Type: Postgraduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Industrial Engineering, Turkey

Approval Date: 2012




This study presents an optimization approach to heat exchanger network synthesis (HENS). HENs are widely used in industry and bring several fluid streams into their desired temperatures by using available heat in the process for efficient usage of energy. Our aim is to provide a network design coupled with a detailed equipment design for heat exchangers. The suggested approach involves discretization of temperatures based on heat load equalities and reformulation as a shortest-path problem, rather than dealing with a nonlinear model and a previously structured HEN, which are common methods in the literature. We generate a shortest path network whose every node corresponds to a heat exchanger alternative and each path represents a HEN design alternative. A mixed-integer nonlinear programming model is solved to design each exchanger alternative in detail, considering all thermo-physical and transport properties of streams at their temperatures and pressures. Our approach has modeling flexibility and successfully finds the required number of heat exchangers and their connections. In addition, one can control the solution quality by deciding on the heat load steps between stream inlet and outlets. Several HEN examples from the literature are solved to assess the performance of our approach and comparable results are obtained.