稠油伴热管道结构参数对停输过程的影响

Impact of structure parameters on shutdown of heat tracing heavy oil pipeline

建立了伴热稠油管道的二维非稳态数学模型,研究了填充介质、保温层厚度及涂层发射率等结构参数对单管停输和双管停输时管内稠油温度分布的影响,进而确定不同参数条件下的安全停输时间。结果表明:单管停输时,温降幅度随填充介质传热系数增大而逐渐降低、随保温层厚度增加而先减小后增大、随涂层发射率降低而逐渐增大;双管停输时,稠油温度均随停输时间近似呈线性降低。对于伴热稠油管道,采用导热泥与涂层均能较大程度降低稠油的温降速率、温降幅度,保温层厚度宜取60mm,其伴热效果较佳,而采用高发射率涂层可延长安全停输时间。

A two-dimensional transient mathematical model for heat tracing heavy oil pipeline is established to study the impacts of structure parameters, such as the filled medium, thickness of the insulation layer, and emissivity of the coating on the temperature profile in the pipeline when single pipeline shuts down and two pipelines shut down. Safe shutdown durations of different parameters are determined. The simulation results show that when one pipeline shuts down, the temperature drop decreases with the increase of the heat transfer coefficient of the filled medium, and it increases with the decrease of the emissivity of the coating, while the temperature drop first decreases and then increases with the increase of the insulation thickness. When two pipelines shut down, the temperature of the heavy oil in the pipeline decreases linearly with the increase of the shutdown duration. Heat conducting mud and coating can significantly decrease the temperature drop rate and temperature drop range. The optimal thickness of the insulation layer is 60 mm. High emissive coating can prolong the safe shutdown duration. （1 Table, 5 Figures, 14 References）