关键词: 功热交换网络, 集成, 多目标优化, 遗传算法, 优化设计

Abstract:

Work and heat exchange network (WHEN) problems refer to the problem of synthesizing the networks considering the work integration and heat integration in the process design, which aims to increase the energy efficiency of the overall system and reduce the costs. In the previous works, the mathematical programming methods are generally used to model and optimize WHENs. However, due to the nonlinear constraints of the pressure transformation process and heat exchanger area calculation, as well as the binary variables of heat transfer matching, the overall model is often a highly nonconvex mixed integer nonlinear programming model, which is difficult to solve. This work proposed an efficient WHEN design method. In the model, turbo expanders and heat exchangers are used to exchange shaft work and heat, respectively. A decomposition algorithm is used in the solving procedure, which uses the genetic algorithm to optimize the key variables in the main problem and uses deterministic algorithms to solve the two sub-network design problems. Multi-objective optimization that minimizes economic and environmental impact is considered in the WHEN model. In the case study, we show the difference between the networks obtained with different optimization goals and the Pareto curve considering the multi-objective optimization, which verifies the efficiency of the proposed method.

Key words: work and heat exchange network, integration, multi-objective optimization, genetic algorithm, optimal design