Wax Deposition in Crude Oil Pipelines

Abstract

ABSTRACT The presence of wax in crude oil can lead to the formation of wax deposits on the walls of pipelines and as a consequence significant increases in pumping pressure caused mainly by an increase in the pipewall roughness. This can be particularly pronounced with the high cooling rates typical of submarine pipelines and is not restricted just to very waxy crudes. Using an extension of standard molecular diffusion theory the parameters influencing wax deposition rates are identified, and from simple laboratory tests on stabilized crude the rate of deposition in full scale pipelines can be predicted. Further, these principles and test methods can be applied to evaluate the effectiveness of the many available deposit-inhibiting additives under conditions appropriate to pipeline operations.