Abstract: A new stepwise optimization method for the minimization of energy and water in multiple-contaminant systems was proposed in this paper. For water networks (WUN), non-isothermal mixing inside unit operations between freshwater and reuse water was considered to reduce the number of heat transfer units. We can only consider heat recovery between freshwater and refuse water in heat exchanger networks (HEN). The nonlinear programming (NLP) model of WUN and mixed-integer nonlinear programming (MINLP) model of HEN were established. An improved particle swarm optimization was proposed for optimizing such systems. The results of an example showed that the optimized network was simpler and 2.4% of annual cost can be saved, indicating the feasibility and effectiveness of the above method.

Key words: multi-contaminant system, water network, heat exchanger network, non-isothermal mixing, particle swarm optimization

摘要： 提出了一种分步综合多杂质体系水网络和换热网络的新方法。对于水网络，考虑进入操作单元的新鲜水与回用水之间的非等温混合，确保流股间的直接热回收；对于换热网络，可以只考虑水网络中的新鲜水和回用水流股之间的换热匹配。采用无进化次数的改进粒子群算法对本文建立的多杂质体系水网络非线性模型和换热网络混合整数非线性模型进行求解。实例表明，与不考虑非等温混合时比较，考虑非等温混合时的最优网络结构更简单，且年度总费用要节省2.4%。因此，本文提出的方法在实际生产中有较好的可行性和有效性。

关键词: 多杂质体系, 水网络, 换热网络, 非等温混合, 粒子群算法