Numerical Study on the Effect of Wax Deposition on the Restart Process of a Waxy Crude Oil Pipeline

A new model for wax deposition is established based on the loop tests data of 9 typical crude oils in conjunction with the concept of the effective wax precipitation which occurs in the heat boundary layer in the pipeline. The thickness of the wax deposition of a waxy oil pipeline is predicted by the established model, and the results of the model agree well with the field data. Subsequently, the models for the shutdown and restart processes of a waxy crude oil pipeline are established. Then the restart process of a wax crude oil pipeline is investigated numerically, the temperature drop during the shutdown process and the transient inlet pressure are presented, and the effect of the wax deposition on the safety of the restart process is clarified.