热油管道停输过程中土壤温度变化规律研究

由于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 ,存油黏度随油温下降而增大 ,存油黏度上升到一定值后 ,会给管道再启动带来极大的困难 ,甚至会造成凝管事故 .为此 ,为了确保安全经济地输油 ,研究了管路停输后的管内油品及周围土壤温度场的变化规律 ,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 ,提出了土壤温度场传热定解问题 ,并通过运用数学分析法 (保角变换、拉普拉斯变换 )对其进行数学求解 ,得出土壤温度场的解析式 .该解析式的计算值比由源汇法及当量环法所得到的解析式的计算值更接近于实际测量值 .编制了相应的软件 ,为更合理地确定在不同季节安全停输时间提供了科学计算依据

Study on the Temperature Field in the Soil Around It During the Shutdown of Heat Crude Oil Pipeline

Because of accidents or the periodical maintenance of the equipment, the shutdown of the pipeline is necessary in the transporting process of heat crude oil. When the pipeline stops transporting, the temperature of the crude oil drops and its viscosity will increase. When the temperature drops to the condensation point of the oil, the restart-up of the pipeline will become very difficult, and even the pipeline is blocked. For the sake of transporting oil safely, it is necessary to study the varying regulation of the temperature field in the soil around the pipeline in order to determine the allowed shutdown time. According to the flow feature of the oil in the pipeline and heat conduction regulation, the analytic expression of the temperature field is obtained with the mathematical methods of conformal transformation and Laplace transformation. The value calculated by this method is closer to the measured value than the values calculated by Source method and Equivalent ring method. The corresponding application software is programmed, by which the safe shutdown time in any season can be determined.