A Study on Thermodynamic and Dynamic Model for Wax Deposit in Pipeline

摘要

Wax deposit is a usual phenomenon in the waxy crude oil pipeline. Wax layer has important influence on safety and cost of pipeline transportation. In order to study wax deposit principal for waxy crude oil pipeline, a set of indoor-pipe experimental unit is designed and set up. Advanced temperature controlling unit and asynchronous velocity modulation unit are used to set experimental conditions. Datum acquired by highly accurate temperature sensors, differential pressure sensors and flow rate sensors are transferred to a computer and analyzed. On the basis of field datum, an experimental plan is worked out. Through a great quantity of experiments the relationships between wax deposit speed and shear stress on inner wall radial temperature gradient dynamic viscosity or concentration gradient are gotten. Stepwise regression method is used to statistically analyze the experiment datum, and a wax deposit law model for waxy crude oil pipeline is established. The model provides a theoretical basis for pipeline company about predicting the wax distribution down pipeline in time and determining pigging period scientifically.