Design and optimization of plate heat exchanger networks

With the features of small minimum temperature approach and high effectiveness, plate heat exchangers are widely used in the energy-intensive process industries to increase heat recovery and reduce greenhouse gas emissions. A major limitation of applying plate heat exchanger is the lack of reliable design methods to optimize a general multi pass plate heat exchanger, Which involves plate pattern and flow arrangement selection with the simultaneous consideration of design constraints. Thus, the optimal design of two-stream multi-pass plate heat exchangers, including gasket plate heat exchangers and welded plate heat exchangers, is proposed. To account for multi-pass flow arrangement, the plate heat exchanger is separated into several pure counter-current or co-current one pass blocks, and in each block the logarithmic mean temperature difference (LMTD) method is used for thermal design. The selection of the number of passes for streams, plate geometries and plate patterns are considered as variables to optimize the total area of plate heat exchanger. The mixed-integer nonlinear programming (MINLP) model (accounting for standardized plate patterns and plate geometries) is formulated in GAMS and completed by ANTIGONE solver. A case study is used to demonstrate the proposed method to obtain the optimal solution With required heat load and constraints. The results show the new optimization design model reduces heat transfer area effectively and saves the computation time compare with previously published methods. The proposed design model can also be applied to the complex plate heat exchanger network design.