针对40万t/a气体分馏装置开工初期易发生丙烯含水量高导致质量不合格的问题，采用Petrosim软件以装置的运行数据为参照建立了装置基础模型，并以装置的标定数据对模型进行了验证，结果表明，模型与装置运行情况吻合较好。采用装置模型对脱乙烷塔顶系统进行了计算，找出影响丙烯质量的因素为塔顶水冷器选型偏大，同时选型偏大会导致循环水流速偏低，水冷器易发生结垢导致泄漏。对水冷器进行了重新选型计算，以保证丙烯质量合格，同时保证循环水流速达标，避免结垢泄漏。

Water content in propylene may possibly be higher in the initial stage of start-up of a 400 kt/a gas fraction unit,which will result in an unqualified quality.In order to solve this problem,a steady state basic model is established by means of Petrosim software taking the operating data of the unit as reference and verified by the calibration data of the unit.Data show that the model can mostly reflect the operating conditions of the unit.The unit model is used to calculate the overhead system of de-ethane tower to find out the factor affecting propylene quality.It is found the overhead water cooler of de-ethane tower is oversized,which is the factor affecting propylene quality and also leads to a low recycled water velocity that cause the water cooler to be clogged easily and leak.Reconfiguration calculation to water cooler is carried out and four schemes are listed as alternative references.