A new approach for the globally optimal design of gasketed plate heat exchangers with variable properties

Abstract

In this paper, we present two novel advances in the design optimization of gasketed plate exchangers. Our first novelty is the use of an ordinary differential model that represents the heat transfer and pressure drop along the surface of the plate considering the variation of the thermophysical properties (density, heat capacity, viscosity, etc.) with temperature. Previous literature did not address this aspect of the problem or addressed it only partially. We also take into account all pass arrangements. Although there is no novelty in this, it adds to making our model comprehensive. The second novelty is the design optimization method used: Partial Set Trimming and Smart Enumeration. This method guarantees global optimality, it is robust (no convergence issues), and it is fast. A new feature added to the Set Trimming methodology is Proxy Set Trimming. The advantage of Set Trimming followed by Smart Enumeration is that there is no need to discretize the differential equations and build very large models with the resulting large number of variables and algebraic equations, rendering highly non-convex models difficult to solve using MINLP procedures. A comparison of the performance of the proposed procedure with two different metaheuristic methods showed that this approach presents better computational performance.