关键词: 埋地管道, 间歇输送, 数值模拟, 温度场

Abstract: The low flow rate of crude oil pipelines is ubiquitous. When the transportation quantity becomes lower than allowed minimum quantity, intermittent transportation technique can be used to solve this problem. In the course of intermittent transportation, if shutdown time is too long and crude oil temperature of pipeline decreases to a certain value, pipeline restart confronts tremendous difficulties, and further probably results in the accidents of pipeline condensation. According to of heating and water power character of pipelines from Tieling to Dalian, based on intermittent transportation, the mathematical models of temperature drop, restart temperature rising and restart pressure were established. By adopting finite difference method, partial differential equation of heat conduction is transferred to linear equations system and comes into solution by iterative method. Taking two sections of pipelines covering Anshan to Da Shiqiao and Da Shiqiao to Xiongyue as examples, simulation calculations of shut-down and restart were conducted. The result shows that pipeline may work safely during winters by this way that pipelines restart and continue work for two days after 8 days shut-down when the oil flow is 23 300 t/d and outgoing temperature is 45 ℃. The method is successfully applied for Tieling-Dalian pipeline.

Key words: Buried pipeline, Intermittent transmission, Numerical simulation, Temperature field