To Insulate or Not: A Perspective Based on Gelation

Gelation of waxy oils during a shutdown can result in difficulties restarting the flow. This is due to the fact that the yield stress of the gel needs to be overcome for restart. The yield stress of a particular oil is dependent on many factors such as the shear and thermal histories of the oil. A gel formed under shear, for example, will be weaker than a gel formed under static conditions. In this presentation, we look at this effect and how it affects the decision of whether to insulate a line or not.