The Study On Wax Deposition Of Jing Xian Crude Oil Pipeline

There will be deposits forming in the pipeline when waxy crude oil transported. The sediment of wax causes many adverse effects on safe and economic running of pipeline. On one hand, it causes the decrease of flow area in pipeline and the increase of friction. The cost of operation and maintenance of pipeline increase, too. On the other hand, the existence of sedimentary layers plays a role in insulation, so that the total heat transfer coefficient and heat loss decreased. There are a large number of sediments found in the Jing’an-Xianyang oil pipeline after it has run for more than 10 years. Therefore, it is needed to analyze its wax deposition situation in order to provide security insurance for the normal operation.In this paper, through the investigation of sediment research status of waxy oil pipeline and the analysis of components and properties of three kinds of oil in Jing’an-Xianyang oil pipeline, the indoor temperature controlled experimental system has been built. The sediment experiments gave the influence patterns of oil temperature, wall temperature, difference of these two temperatures and flow rate on the wax deposition of the three kinds of oil. Moreover, according to the experimental results, the wax deposit dynamics model was established by the method of stepwise multiple regression. The FLUENT software was used to analyze the thermal state of the test section and the deposition laws of crude oil samples in experiment system. Through the analysis of the operation of Jing’an-Xianyang oil pipeline and the combination of its actual topography, this paper used ANSYS simulation software to analyze the possible factors that causes the destruction of waxy sedimentary layer or even the blocking of the pipeline. After the analysis of the available pigging methods, heat washingthe gradual warming of the pipeline was recommended to remove the sediment in Jing’an-Xianyang oil pipeline. Meanwhile, in order to ensure the safe and economical operation of Jing’an-Xianyang oil pipeline, some concrete measures were presented and the variation regularities of temperature field in heat washing process were analyzed, too.