Numerical investigation of wax deposition features in a pipeline under laminar flow conditions

Abstract

Wax deposit inside pipelines continues to be a critical issue in the oil and gas industry. The available wax deposition data in the literature are currently insufficient to construct viable predictive numerical methods that capture all wax deposit features. Therefore, more research studies are required to improve our understanding of the physics of wax-deposition phenomena. In the present paper, a numerical study is performed to predict the temporal and spatial distribution of the porous wax deposit during laminar flow in a pipe. A mathematical model which combines the energy and momentum balance equations and molecular diffusion model by Fick's law is employed to better describe the wax deposit. Validation with experimental data as well as numerical results and characteristics of wax deposition are presented. The results revealed that an increase in the deposition time and porosity leads to a significant increase in the wax deposit content and pressure drop, and a decrease in the fluid temperature, heat transfer coefficient, and flow rate. However, an increase in porosity leads to larger variation of these parameters over a short period of time. Further, it is demonstrated that the wax deposit is concentrated over a short axial length, and its maximum which appears at X/L = 0.014 is kept unchanged with time and porosity variation.