Abstract: The optimal water system with regeneration recycling can minimize freshwater consumption and wastewater discharge to the largest extent, and thus it has drawn much attention in academic and industrial circles. After introducing the regeneration process in a water-using system, the limiting water supply line will be changed, causing the possible change of the location and number of pinch points. Based on prior approach to constructing the optimal water supply line in regeneration recycling water systems, the influence factors on the change of pinch point when introducing the regeneration process were analyzed, such as the position and concave degree of concave points on the limiting composite curve and the flowrate relationship of the stream with highest concentration and freshwater. The change of the position and number of pinch points could be obtained, providing theoretical guidance for analysis and design of water-using networks.

Key words: water pinch, regeneration, recycling, graphical method, global optimization

摘要： 引入再生循环的最优水系统可以最大限度地节约新鲜水的用量和减少废水的排放，是当前节水技术研究的重点。用水系统引入再生过程后，极限供水线会发生变化，从而水系统夹点个数以及位置都可能会发生变化。运用前人总结出的再生循环过程最佳供水线的构造方法，分析影响引入再生过程后夹点位置变化的因素，发现引入再生过程前后夹点位置的变化情况与以下因素有关：极限复合曲线上的凹点位置以及凹向极限供水线的程度和最高浓度用水单元水流率与新鲜水流率的关系，并分析得出夹点位置的变化规律，从而为用水网络的分析和设计提供理论性的指导。

关键词: 水夹点, 再生, 循环, 图示法, 整体优化