A MILP-Based Iteration Method for Heat Exchanger Network Synthesis

Heat exchanger network (HEN) synthesis is an efficient way for Heat Integration in the process industry. The non-linear nature of the problem leads the solution to easily be trapped into local optima. This work proposes a mixed-linear programming model (MILP)-based iteration method for HEN synthesis. The MILP aims to minimise the total annualised cost, including utility and investment cost. The logarithmic mean temperature difference (LMTD), heat transfer area, and the investment cost are linearised. The coefficients of the linearised equations are obtained by data regression. And they are evolved through the designed iteration algorithm. Two cases have been tested to show the effectiveness of the proposed method. Results show that the proposed method is accurate on the calculation of total annualised cost, the errors for Case 1 and 2 are 0% and 0.082% compared to the results calculated by the original equations. This provides a way to solve the HEN synthesis problem in a reasonable computational time and obtain the optimal solution.