Computational Fluid Dynamics Study of Solids Deposition in Heavy Oil Transmission Pipeline

Corrosion: October 2012, Vol. 68, No. 10, pp. 904-912
Computational Fluid Dynamics Study of Solids Deposition in Heavy Oil Transmission Pipeline
X. Landry*, A. Runstedtler‡,*, S. Papavinasam**, and T.D. Place***
arunsted@nrcan.gc.ca
* Natural Resources Canada, Canmet ENERGY, 1 Haanel Drive, Ottawa, Ontario, K1A 1M1, Canada.
** Natural Resources Canada, CANMET Materials Technology Laboratory, 183 Longwood Road South, Hamilton, Ontario, L8P 0A5, Canada.
*** Enbridge Inc., 10201 Jasper Ave., Edmonton, Alberta, T5J 2J9, Canada.
Abstract
Studies have shown that transmission-quality heavy crude oil carries water-wetted solid particles.  Such particles can accumulate on the pipe floor and cause under-deposit corrosion.  The incidence of accumulation is strongly correlated to locations downstream of over-bends.
Authors describe a computational fluid dynamics (CFD) analysis of light and heavy oil flow in a representative segment of an actual transmission pipeline with observed corrosion.  The intent was to determine the key processes affecting deposition in heavy oil that do not occur for light oil and to offer suggestions for mitigation. Their analysis suggests that the key effect in determining whether particles become trapped is the near-wall velocity of the flow.  They found this to be significantly lower for heavy oil compared to light oil, especially downstream of over-bends. This causes particles near the pipe floor to move slowly and makes them susceptible to becoming trapped.  The key process affecting deposition is not the tendency of particles to fall to the pipe floor, which occurs more readily in light oil than heavy oil.  Instead, it is the ability of the flow to keep particles moving along the pipe floor.
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