WASHINGTON -- Diluted bitumen has no greater likelihood of accidental pipeline release than other crude oils, says a new report from the National Research Council. The committee that wrote the report found that diluted bitumen has physical and chemical properties within the range of other crude oils and that no aspect of its transportation by pipeline would make it more likely than other crude oils to cause an accidental release. The committee was not asked to address whether the consequences of a diluted bitumen release differ from those of other crude oils.
Bitumen is a dense and viscous form of petroleum that will flow in oil pipelines only when it is diluted with lighter oils. Diluted bitumen has been imported from western Canada for more than 30 years and is transported through numerous pipelines in the United States. With bitumen imports from Canada's oil sands on the rise, Congress passed legislation in January 2012 calling upon the secretary of transportation to determine whether any increase in the risk of a release exists for pipelines transporting diluted bitumen. The U.S. Department of Transportation asked the Research Council to convene an expert committee to analyze one aspect of this risk: whether pipelines transporting diluted bitumen have a greater likelihood of release compared with pipelines transporting other crude oils.
The study committee reviewed pipeline incident statistics and reports of investigations; analyzed data on the chemical and physical properties of diluted bitumen; examined the technical literature; consulted experts in pipeline failure mechanisms such as corrosion and cracking; queried pipeline operators on their operations and maintenance practices; and solicited comments from the public.
The committee did not find any causes of pipeline failure unique to the transport of diluted bitumen. In addition, it found no physical or chemical properties outside the range of other crude oils and no evidence that pipeline operators manage or maintain their systems any differently when transporting diluted bitumen compared with other heavy crude oils.
"Diluted bitumen has density and viscosity ranges that are comparable with those of other crude oils," said Mark Barteau, professor of chemical engineering at the University of Michigan and chair of the committee that wrote the report. "It moves through pipelines in a manner similar to other crude oils with respect to flow rate, pressure, and operating temperature. There's nothing extraordinary about pipeline shipments of diluted bitumen to make them more likely than other crude oils to cause releases."
The report also says that shipments of diluted bitumen do not contain higher concentrations of water, sediment, dissolved gases, or other agents that cause or exacerbate internal corrosion, including microbiologically influenced corrosion, and the organic acids in diluted bitumen are not corrosive to steel at pipeline operating temperatures. In addition, the committee found no properties in diluted bitumen that could make transmission pipelines more vulnerable to erosion, external corrosion and cracking, or damage from mechanical forces.
The study was sponsored by the Pipeline and Hazardous Materials Safety Administration of the U.S. Department of Transportation. The National Research Council is the principle operating arm of the National Academy of Sciences and the National Academy of Engineering. Together with the Institute of Medicine, these private, independent nonprofit institutions provide science, technology, and health policy advice under a congressional charter granted to NAS in 1863. For more information, visit http://national-academies.org. A committee roster follows.
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NATIONAL RESEARCH COUNCIL
Transportation Research Board
Committee for a Study of Pipeline Transportation of Diluted Bitumen
Mark A. Barteau* (chair)
DTE Energy Professor of Advanced Energy Research, and
University of Michigan
Y. Frank Cheng
Professor and Canada Research Chair in Pipeline Engineering
Mechanical and Manufacturing Engineering
Schulich School of Engineering
University of Calgary
James F. Dante
Materials Engineering Department
Southwest Research Institute
H. Scott Fogler
Vennema Professor of Chemical Engineering and Arthur F. Thurnau Professor
Department of Chemical Engineering
University of Michigan
O.B. Harris LLC
Missouri City, Texas
Brenda J. Little
Stennis Space Center
Naval Research Laboratory
Stennis Space Center, Miss.
Professor of Nuclear and Reliability Engineering
Department of Mechanical Engineering
University of Maryland
W. Kent Muhlbauer
WKM Consultancy LLC
Professor of Chemical Engineering, and
Institute for Corrosion and Multiphase Flow Technology
Joe H. Payer
Research Professor of Corrosion and Reliability Engineering
Department of Engineering
University of Akron
Richard A. Rabinow
Rabinow Consortium LLC
George W. Tenley Jr.
Thomas R. Menzies Jr.
* Member, National Academy of Engineering
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