Study On The Optimization Rules And Solution Tactics Of HEN

Heat exchanger network (HEN) is an important subsystem of energy recovery process. That whether the structure of HEN is rational and the parameters of HEN are excellent or not is important for economizing energy in process industry and reducing consumed energy. To solve these aspects, we must synthesize and optimize heat exchanger networks.(1) On the former works of the optimization of HEN, this paper summarizes the optimization principles in many aspects, such as on the minimization of the area of heat exchangers, the minimization of the energy, the minimization of the number of heat exchangers. At last, eight principles of the optimization of HEN are summarized. This paper analyses the connection of the total area of heat exchangers and the exchanging temperatures. And the connection of the amount of utility and the expense of effectual energy is also analysed. The optimization principles can qualitatively guide the optimization of HEN.(2) For the non-protuberant nonlinear many apices and complex MINLP, the traditional methods are hardly to solve it. So I try to find a appropriate method. Through reading a great deal of literature, I find tabu search method is felicitous. Therefore this paper deeply study and discuss the method of tabu search and probe into the basic theory of tabu search. And this paper also discusses the tabu search method's characteristic and basic elements. At last, the tabu search method is improved to solve the MINLP of HEN. To validate the improved tabu search method feasible, a test-function is used. Through count and discussing, I find that the improved method can escape from the locally best answer and soon get to the entirely best answer. This proved that the improved tabu search method (ITSM) on solving MINLP is feasible and effectual.(3) Using C language I write the computer software. This paper analyses two examples. One is how to improve parameters of a heat exchanger network with a certain structure and make them to be optimal. Another is when the streams have branches, how to optimize the flow of the HEN and the inlet and outlet temperatures of the streams to recover the maximum energy. The mathematical model of the HEN is established. And the results are satisfying. Compared with literature, it indicates that the results by applying ITSM are better. And another advantage is that solving questions by applying ITSM is much faster. This is meritorious in the engineering research and innovation. So the ITSM is effectual and practical.