A Simultaneous Optimization Approach for Synthesis of Flexible Heat Exchange Networks with Uncertain Temperatures and Flowrates

A strategy is proposed for the synthesis of a flexible heat exchange network (HEN) that involves specified uncertainties in the source-stream temperatures and flow rates. The problem is decomposed into three main iterative steps: (1) the simultaneous HEN synthesis to attain a network configuration with a minimum total annual cost (TAC); and (2) the flexibility analysis to test the feasible operation of the network over the full range of uncertain parameters; (3) the exclusion of disqualified networks. For those networks resulting from the synthesis step that are not passing the examination of the flexibility analysis, some integer cuts are appended to forbid reconsidering the disqualified network configurations. A few iterations are required between the synthesis and the flexibility analysis steps. One numerical example is used, demonstrating the efficacy of the proposed flexible HEN synthesis method.