Graph-theoretic control structure synthesis for optimal operation of heat exchanger networks

In this paper, a recently developed procedure for the selection of control structure of heat exchanger networks for optimal operation is improved and reformulated in a graph-theoretic setting. A graph representing take-over relationship between the manipulations is constructed to generate the feasible split-range pairs based on active constraint regions. These feasible split-range pairs are then used to calculate a structural coupling matrix on the basis of the relative degree. The optimal control pairings are thus obtained through the solution of a bipartite matching problem, taking the structural coupling matrix as the weight matrix. A case study is used to verify the application of the proposed method.