成品油管道在顺序输送中会产生混油，减少混油量是成品油管道运行中必不可少的环节。通过计算兰郑长成品油管道郑州站混油量，整理、分析近两年郑州站实际混油量，并进行比较分析，得出郑州站混油实际切割量大的原因：停输界面位置不合理、阀门行程时间长等。提出将罐区收、发油共用1根汇管改为收、发油分别设1根汇管,在站外增加1台密度计，减少停输次数，统一密度计的标定工作等改进建议。

In product oil pipeline batch transportation, mixed oil will be inevitably formed and oil mixture volume decrease becomes indispensable for oil product pipeline operation and management. Calculated is the oil mixture volume at Zhengzhou station in Lan-Zheng­Chang oil product pipeline, conducted is comparative analysis on the actual oil mixture volume data obtained at Zhengzhou station in recent two years and found out is the cause of actual large cutting volume at the station: unreasonable shutdown interface position and long valve stroke time. Proposed are such suggestions as change of one manifold into two manifolds for oil delivery in the tank area, addition of a density meter, decrease of the number of shutdown and unification of density meter calibration.