Application of plate heat exchangers into heat exchanger networks retrofit with fixed structure

Heat exchanger enhancement technologies have been widely used into heat exchanger networks (HENs) retrofit. However, the heat recovery is limited through the enhancement, which is restricted by the geometry of existing heat exchanger. Plate heat exchangers are widely used in energy-intensive process industries to increase heat recovery and reduce greenhouse gas emissions with the features of small minimum temperature approach and high effectiveness. Thus, plate heat exchangers are taken into consideration to replace conventional heat exchanger in crude oil preheat trains to enhance heat transfer coefficient and reduce energy consumption. A major limitation of applying plate heat exchanger is lack of reliable optimization method to quantity the energy saving effectively. Due to the high installation cost of plate heat exchangers, the optimization is based on the trade-off between energy reduction and capital cost. This work proposes a new methodology of application of plate heat exchanger in HENs retrofit with a fixed network structure. A change in one component in heat exchanger networks can have an effect on other downstream heat exchangers. Therefore, the proposed methodology also presents a way of eliminating the need for additional heat transfer area after replacement, while ensuring the stream target temperatures are met. Case studies highlight the benefits of the new approach.