Crude oil from the Bakken Shale isn't significantly more dangerous than crude from other plays to transport by rail and poses a lower transport risk than other flammable liquids, but it may contain higher amounts of dissolved flammable gases compared to heavier crudes, according to a report commissioned by the American Fuel & Petrochemical Manufacturers (AFPM).
AFPM, which represents nearly all of the petroleum refiners and petrochemical manufacturers in the United States, said it surveyed 17 of its members and collected approximately 1,400 samples of Bakken crude for its 38-page report, which was released Thursday. The trade association said it commissioned the report at the request of the U.S. Department of Transportation (DOT).
"The results show that while Bakken crude (and other light crudes) may contain higher amounts of dissolved flammable gases compared to some heavy crude oils, the percentage of dissolved gases would not cause Bakken crude to be transported under a DOT hazard class other than Class 3 Flammable Liquid and does not support the need to create a new DOT classification for rail transportation," the report said.
DOT has been investigating a series of train derailments involving rail cars containing Bakken crude. The investigation is part of DOT's Operation Classification, also known as the "Bakken Blitz," (see Shale Daily, Feb. 26).
Last February, DOT issued an emergency order [Docket No. DOT-OST-2014-0025] requiring rail carriers to test crude oil before transport, and to classify crude as a Packing Group (PG) I or II hazardous material, effectively forbidding its classification under PG III, a “low danger” category.
DOT issued a second emergency order last week [Docket No. DOT-OST-2014-0067], advising against the use of older, more vulnerable rail cars for the shipment of Bakken crude (see Shale Daily, May 7). Railroads were also required to notify the appropriate state emergency response commissions when the trains carrying more than 1 million gallons of Bakken crude are moving through their states.
According to the AFPM survey, the flashpoint for Bakken crude ranged from -59 to 50 degrees Celsius. The trade association said that meant it meets the criteria for transport as a PG I, PG II or PG III material or as combustible liquids. It also found that Bakken crude's initial boiling point ranged from 2.2 to 66.9 degrees Celsius. AFPM said oil with an initial boiling point of 35 degrees Celsius or lower could be shipped as PG I, but other oils could be sent as PG II, PG III or as combustible liquids.
The vapor pressure of Bakken crude at 50 degrees Celsius tested at a maximum 16.72 pounds per square inch absolute (psia). Meanwhile, rail tank car pressures on delivery tested at a maximum of 11.3 pounds per square inch gauge (psig), which AFPM said demonstrates that Bakken crude may be safely transported in DOT Specification 111 tank cars.
"Measured tank car pressures show that even the older DOT 111's authorized to transport Bakken crude oil are built with a wide margin of safety relative to the pressures that rail tanks may experience when transporting Bakken crude oil," the report said.
Last week, two DOT agencies -- the Federal Railroad Administration (FRA) and the Pipeline and Hazardous Materials Safety Administration (PHMSA) -- issued a safety advisory strongly urging those shipping or offering Bakken crude to use tank car designs with the highest level of integrity available in their fleets. The agencies advised offerors and carriers to try and avoid using older legacy DOT Specification 111 or CTC 111 tank cars for the shipment of Bakken crude.
AFPM added that of all the samples taken of hydrogen sulfide (H2S) concentrations, only one sample tested above the short term exposure limits set by the Occupational Safety and Health Administration. The lone high sample tested at a maximum 23,000 ppm. "Where they exist, high H2S concentrations are addressed under existing transportation and workplace safety regulatory provisions without affect to rail tank car authorizations," the report said.
The report also compared the Reid Vapor Pressure (RVP) -- a measurement for volatility -- of Bakken crude to other types, including crude from the Eagle Ford Shale in Texas and the Denver-Julesburg (DJ) Basin in Colorado. Other crudes tested were Louisiana Sweet (LLS), West Texas Intermediate (WTI), Arabian Super Light, Agbami, Sarahan Blend, Brent, Alvheim blend, Arabian Heavy, Alberta Dilbit and Alba.
The report said Bakken crude had an RVP of 7.83 psia. By comparison, crude from the DJ Basin tested at 7.82 psia, the Eagle Ford was 7.95 psia, LLS was 4.18 psia and WTI was 5.90 psia. Arabian Super Light tested at the highest RVP (20.7 psia) while Alba was the lowest (1.6 psia).
"While survey data on specific samples of Bakken crude oils (like other light crude oils) showed higher gas content than assay data, it may be expected that similar variations arise in the case of non-Bakken crude oils," the report said. "The data suggests that Bakken crude oil is within the norm for what might be expected in the case of light end content in light crude oils."
The report was prepared by Frits Wybenga, hazardous materials consultant for the Rockville, MD-based firm Dangerous Goods Transport Consulting Inc.
Last July, an unattended freight train transporting Bakken crude rolled downhill, derailed and exploded in Lac-Megantic, Quebec, killing 42 people (see Shale Daily, July 9, 2013).
Six months later, a 90-car crude oil train loaded with Bakken crude heading to a refinery in Florida derailed in a rural area near Aliceville, AL. According to DOT, more than 20 cars derailed and at least 11 ignited, causing an explosion and fire. Although no one was injured in the incident, an undetermined amount of crude fouled a wetlands area, causing an estimated $3.9 million in damage.
On Dec. 30, 2013, a BNSF train carrying Bakken crude hit a grain train traveling in the opposite direction that had derailed earlier near Casselton, ND. The crash caused 21 cars carrying crude to derail, 18 of which subsequently ruptured and exploded (see Shale Daily, Dec. 31, 2013). There were no injuries, but about 1,400 were evacuated. Damage was estimated at $8 million.