Detailed Design Of Heat Exchanger Under The Framework Of The Energy Conservation Of Heat Exchanger Network

Heat exchanger network is an important system as well as major method of energy-saving,cost-reducing and energy recovery during oil refining process industry.In order to realize the energy-saving and cost-reducing of the whole system,the scholars optimized the heat exchanger networks.But these methods ignored the detailed design of the single heat exchanger.In recent years,many scholars have presented lots of methods for the optimal synthesis of heat exchanger network.Some scholars analyzed the optimal synthesis of heat exchanger based on pressure drop constraint,while others analyzed it based on heat transfer coefficient.But they did not take account of the detailed design of the single heat exchanger.The number of tubes and shells passes and the parameters of detailed design of heat exchangers have a great influence on the energy-saving of the heat exchanger network.However,the result of optimal synthesis of heat exchanger network can be affected by the result of detailed design of a single heat exchanger.So it's necessary to consider every result of detailed design of a single heat exchanger throughout the optimal synthesis of heat exchanger.For the widely application of multi-pass tube and shell heat exchangers,this paper puts forward a method for detailed design of multi-pass heat exchangers under the framework of the energy consumption,optimization and integration of heat exchanger networks,which considers both the optimal synthesis of heat exchanger network and the detailed design of the heat exchangers.The author firstly designs heat exchangers in detail based on the TEMA standard and analyzes the influences that the result of detailed design of heat exchangers exert on energy-saving and cost-reducing of heat exchanger network.The result of optimal synthesis of heat exchanger network can be affected by the result of detailed design of a single heat exchanger.Then the author deducts expression of correction factor F_T on the basis of the heat transfer principle of multi-pass heat exchangers as well as analyzes influences the number of tube passes impose on correction factor F_T.Setting the tube location and heat transfer surface as variables and minimum total cost as objective function value,the author uses mixed integer nonlinear optimization program(MINLP)to solve the heat exchanger transfer,obtain the number of the tubes and shells of the heat exchanger and compute the heat transfer temperature difference correction factor F_T at the same time.The author optimally synthesizes the heat exchanger network while considers the detailed design of the heat exchanger.Finally,in terms of the influence of the detailed design of the heat exchangers,the author proposes a composition decomposition strategy based on the TEMA standard to achieve the goal of detailed design of multi-pass heat exchangers under the framework of the energy consumption.The example results show that the detailed design of the heat exchanger influence the optimal synthesis of the heat exchanger network,and the structure of the heat exchanger network influence the design of the heat exchanger.In order to realize the goal of energy-saving and cost-reducing,both the detailed design of the heat exchanger and the optimal synthesis of the heat exchanger network must be considered simultaneously.