换热网络运行模拟优化

换热网络系统大多数是按给定工况，以投资费用和运行费用最优为目标设计的。但在实际运行过程中，确定和不确定性的影响因素往往导致换热网络的运行工况偏离设计值。偏离设计工况运行的换热网络性能变差，导致运行费用增加，甚至不能满足工艺物流换热要求。在换热网络结构给定条件下，将满足物流目标温度和运行费用最优作为目标函数，以单体模型和Yee et al.（1990）提出的多级超结构为基础，建立换热网络运行模拟优化模型，并进一步去除恒定膜传热系数假设使模型贴近实际问题。针对提出的非线性数学模型（NLP）问题，以标准粒子群算法为基础建立求解策略。在论文的最后，4个来源于已发表论文的实例研究证明了该优化方法的有效性。

Optimal operation of heat exchanger network

Most design methodologies for heat exchanger network are based on fixed parameters,with the objectives of minimum capital and operating costs.However,changes in operating parameters might cause deviation from optimality or even fail to satisfy target temperatures.A general model was proposed for optimal operation of heat exchanger network,aiming to achieve two goals: ① all controlled temperatures were kept at their targets;② operating cost was minimized.The model was formulated as a non-linear programming problem,which consisted of exchanger model,splitter model,mixer model,by-pass model and relation model between unit models.The HEN structure was represented with stage-wise superstructure presented by Yee and Grossmann(1990),which was developed for considering non-constant film coefficient.A solution strategy based on particle swarm optimization algorithm was developed for NLP problem,which promised simple,fast and robust searching procedure.The proposed method was applied to three benchmark problems reported by published literatures,and the results proved that the method was more effective in solving optimal operation problem of heat exchanger network.