The additional sulfur can lead to the weakening or embrittlement of pipelines. Tar sand oil’s high concentrations of chloride salts can lead to stress corrosion in high temperature pipelines. Higher quantities of abrasive quartz particles can also be found.
This combination of chemical and physical abrasion can dramatically increase the rate of pipeline deterioration.
The resulting corrosion and abrasive nature of tar sand crude is heightened by the relatively high heat and pressure by which these pipelines are used to transport the thick Dilbit.
While industry defines high pressure at 600 psi, tar sands pipelines operate at up to 1440 psi and temps up to 158°.
The pipeline industry and the National Academy of Sciences study (see text box at left) say that other types of crude oil than diluted bitumen have these same properties. Environmentalists consider such a narrow conclusion to be irrelevant.
1.^William Lyons and Gary Plisga, Standard Handbook of Petroleum and Natural Gas Engineering, Burlington, MA: Gulf Professional Publishing, 2005, p. 4-521
2.^Planning Ahead for Effective Canadian Crude Processing, Baker Hughes, 2010, p. 4, http://www.bakerhughes.com/news-and-media/resources/white-papers/effective-canadian-crude-processing; A.I. Williams, Degradation Mechanisms in the Oilsands Industry, Calgary, Alberta: Ammonite Corrosion eng. Inc. 2006
3.^2008 NPRA Q&A and Technology Forum: Answer book, Champion's Gate, FL: National Petrochemical and Refiners Association, 2008, Question 50, Desalting, http://www.npra.org/forms/unploadFiles/17C490000055.filename.2008_QAAnswer_Book.pdf (no longer available at this address; see http://www.proceedings.com/05085.html)
4.^Henry Liu, Pipeline engineering, Boca Raton, FL: CRC Press LLC, 2003, p 317
5.^"Keystone Pipeline, USA" Net Resources International, 2011, Draft Environemtnal Impact Statement for Keystone XL, Appendix L: Pipeline Temperature Effects Study, U.S. Dept. of State, 2010, http://keystonepipeline-xl.state.gov/documents/organization/182235.pdf