Experimental and mathematical modeling of wax deposition and propagation in pipes transportating crude oil

Abstract

A novel model for predicting wax deposition during turbulent and laminar flow of crude oil was developed. Experiments carried out using a mixture of toluene and an oil wax cut, in a laboratory flow loop, revealed model results on total mass of wax deposition showing a very conformity with experimental findings in the laminar flow regime. Molecular diffusion was the dominant mechanism during laminar flow. Sloughing effect was an important mechanism during wax deposition in the turbulent flow regime that should not be neglected. In the turbulent flow regime, there were critical flow rates for any system containing non-isothermal flow of waxy crude oil. These critical rates depended on the fluid (oil) characterization and pipeline characteristics, as well as operational conditions. Increasing flow rate beyond the critical flow rate decreased the amounts of wax deposit. These trends were similar to what were concluded in other experiments.