Abstract: Establishing an unsteady heat transfer model for the period of pipeline shutdown combined with the thermodynamic properties of exposed pipelines, calculating physical parameters of crude oil in two conditions which changed with temperature and never changed with temperature, the result of the latter condition had great difference with the actual shutdown situation. Therefore physical parameters changing with temperature should be considered. Based on physical parameters of crude oil changing with temperature, changed the factors affecting the shutdown temperature drop such as the shutdown starting oil temperature, ambient temperature and insulation thickness and calculating the safe shutdown time under different conditions. The results show that the growth rate of the safe shutdown time was basically the same with the gradual increasing of the initial oil temperature and the thickness of the insulating layer and the rate of increase was the same and the growth rate of safety shutdown time was increasing with the gradual increasing of ambient temperature and the rate of increase was the same.

Key words: Crude oil physical parameters, Safe shutdown time, Start oil temperature, Ambient temperature, Insulation thickness

摘要：  结合裸露管线的热力特性, 建立管道停输时非稳态传热模型, 分别计算了原油物性参数随温度变化和不随温度变化两种条件下的安全停输时间。结果表明, 在原油物性参数不随温度变化的条件下所得结果与实际停输情况有很大差别, 因此应考虑物性参数随温度的变化。在原油物性参数随温度变化的情况下, 改变影响停输温降的因素如停输起始油温、 环境温度、 保温层厚度, 计算了不同条件下的安全停输时间。计算结果表明, 停输起始油温以及保温层厚度逐渐增大且增加幅度相同时, 安全停输时间增加的幅度基本相同; 外界环境温度逐渐升高且增加幅度相同时, 安全停输时间的增长幅度越来越大。

关键词:  原油物性参数, 安全停输时间, 起始油温, 环境温度, 保温层厚度