An Inherent Safer Heat Exchanger Network Design Considering Economy And Safety Optimization

The inherent safer process design is one of the most effective and important ways amongthe chemical process protection layers,which received more and more attentions from practitioners and scholars all over the world.Heat exchanger network(HEN)synthesis is one of the most effective ways to improve energy efficiency,achieve high-efficiency as well as energy saving.With the urgent needs of the transformation and upgrading of the chemical industry as well as accelerating the transformation of development modes,the research on optimization design of inherent safer HEN is of great significance to save energy,reduce emission and make sustainable development in chemical industry.The thesis quantified inherent safety of chemical process,and then,mathematical programming is used to establish a mathematical model of inherent safety and HEN synthesis.In order to obtain inherent safer HEN,linear weighted sum method is used to optimize safety and economy simultaneously.The main research contents can be stated as follows:(1)Simulation and safety evaluation of heat exchangers and HEN: First,evaluation index method is used to quantify the inherent safety explosiveness,toxicity and inventory for the HEN.Then,heat exchanger and HEN are simulated and inherent safety explosiveness,toxicity and inventory are evaluated.The results show that improving the inherent safety of the HEN will increase the economic costs of the HEN instead.(2)Simultaneous optimization for economy and safety of heat exchanger network:Because improving the inherent safety of the HEN will increase the economic costs of the HEN,simultaneous optimization for economy and safety of HEN is necessary.Based on the quantification of inherent safety,mathematical programming is used to establish a mathematical model of economy and safety for HEN.Normalization method is used to get the objective function of economy and safety.Linear weighted sum method is used to solve the model in order to obtain inherent safer HEN.The results show that considering inherent safety explosiveness tends to exchange heat with safer process streams,and forbid explosive process streams to exchange heat.Considering inherent safety toxicity tends to reduce the numbers of toxic process streams flowing through the heat exchanger,which will reduce the possibility of leaking.Considering inherent safety inventory tends to reduce the inventory of HEN,which will reduce the severity of accident.(3)The multiobjective optimization of inherent safer heat exchanger network: To obtain the Pareto front,linear weighted sum method with variable weight is used to simultaneously optimize the explosiveness,toxicity,inventory and economy of HEN.Optimal HEN was put forward based on the Pareto front of illustrative example considering greater economic weight.