埋地热油管道停输轴向温降规律研究

The Study of Axial Temperature Drop of Shutdown on Buried Crude Pipeline

热油管道的计划检修和事故抢修都在管线停输情况下进行 ,停输后 ,管内存油油温不断下降 ,存油粘度随油温下降而增大 ,当粘度增大到一定值后 ,会给管道输送再启动带来极大的困难 ,甚至会造成凝管事故。为了确保安全经济地输油 ,必须研究管路停输后的温降情况 ,以便确定允许停输时间。根据热油管道停输后油品和管道周围土壤的热力变化工况 ,提出了传热定解问题并对其进行数学求解 ,得出了管道中油品轴向温度随时间和距离变化的解析解 ,并编制了相应的软件 。

Stopping transportation of the pipeline is necessary when breakdown occurs in the transportation systems and when equipment needs repairing periodically. When crude oil pipelines shutdown, the temperature of the oil left in the line drops and the viscosity increases. The work of restart up will become very difficult, and even blocking line will happen if the temperature drops to condensation point. For the sake of transporting oil safely, it is necessary to study the situation of temperature drop to make sure the allowed shutdown time. A definite solution problem on heat conduction is obtained according to the flowing feature of the pipeline and heat condition of soil that surrounds the pipeline. After finding the solution, the analytic solution of the changed axial oil temperature relating to distance and time has been obtained, the corresponding program software has also been programmed which provides a scientific basic for determining safe shutdown time in different season.