Obstruction of Pipelines During the Flow of Waxy Crude Oils

Abstract

When a liquid solution is cooled as it flows laminarly through a tube, a radial concentration gradient is established, which causes mass transfer of the solute to occur toward the tube wall. The solute precipitates off the solution in the neighborhood of the wall, and adheres perfectly to it. The deposited mass gradually obstructs the conduit, affecting the pressure and flow fields. A simple model is presented that gives the thickness of the deposited layer as a function of axial position and time. The liquid solution is assumed to behave according to the Herschel-Bulkley rheological model. Results are presented in the form of time evolution of axial distributions of pressure, temperature, layer thickness, global heat transfer coefficient and Reynolds number.