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

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