Classification of crude oil transported by rail from shale plays

Intertek, a nationally recognized third-party testing company, discusses the complexities of classifying crude from shale transported via rail.
By Scott Blakely and Kesavalu Bagawandoss | May 14, 2014

These are the headlines:
“Crude-by-Rail has been termed as Dangerous to Communities.” “City Council votes to oppose rail transport of crude oil.”  “Oil in train explosion… (was) mislabeled.”  “Oil profits before safety!” These are some of the recent news headlines that have emerged around the crude oil industry.

While there have been train derailments and subsequent deaths, including the disaster that occurred in Lac-Megantic, Quebec, that killed 47 people, these were misfortunate incidents caused by mechanical, procedural, or environmental factors on a container carrying a flammable liquid. The media has sensationalized claims that the mislabeling of crude oil has created a dangerous situation. In fact, Transport Canada has termed Crude Oil as a dangerous substance.

The news media proclaimed that the crude oil railcar derailment, responsible for deaths, was misclassified with a safer packing group (PG) III designation rather than its proper and more dangerous PG II designation on the paperwork.  Although this is true, what they failed to mention was that this crude oil was transported in dangerous goods DOT-111 tank cars, which are acceptable for even PG I material, which is considered the highest danger.  While the paperwork was wrong, the railcar selection was proper. It should have had no effect on emergency response as the emergency guide references crude oil only as UN 1267 and not by any packing group designation.

Why Is Crude Oil Transport An Issue Now?
Shale oil and gas exploration has revolutionized the energy outlook for the United States as well as the global market. Today, the United States is self-sufficient in natural gas and is approaching the same for crude oil production. This is due to hydraulic fracturing utilizing the horizontal drilling technology. This technology has transformed the global energy Initiatives. This has led to the change in the crude oil landscape and the challenges associated in transport, quantity, quality and safety aspects.

Transportation of crude oil has become a challenge. Existing pipeline capacity is far below what is necessary. Pipeline construction takes significantly more planning, approval, and time as demonstrated by the still unapproved Keystone Pipeline.  Rail transportation allows some flexibility of movement and allows market factors such as quality and price to select destinations rather than pipeline routes.

Information about hydraulic fracturing is popular as the public’s request for details of this fast growing energy sector continues to increase.  As the story goes, it is great for the economy and takes a toll on the environment.  People are being pushed to take sides.  Anti-fracking campaigns have been waged.  Pipelines go unapproved.  Now, crude oil transportation by rail has gained attention among the media with increased inquiries from the public. 

US DOT Emergency Order
The U.S. Department of Transportation had to address these growing concerns.  It issued an Emergency Order requiring stricter standards for transporting crude oil by railcar as part of its Operation Classification.  Those offering crude oil for transportation by rail must ensure that the product is tested and properly classified in accordance with 49CFR parts 172 and 173. Failing to comply is subject to civil penalties up to $175,000 for each violation or each day they are found in violation.

Proper classification helps to ensure that the material is properly packaged and that risks are accurately communicated to emergency responders. Crude oil is defined as a naturally occurring, unrefined petroleum product composed of hydrocarbon molecules and is described as Petroleum Crude Oil, UN1267, Class 3, PG I, II, or III in the U.S. Hazardous Materials Regulations.  It is usually a flammable liquid just like gasoline, which is not surprising as gasoline is often a compositional fraction of crude oil.  Even “green products” such as ethanol are flammable liquids and would have wreaked havoc in a derailment incidence.

Testing Crude Oil
The U.S. DOT Emergency Order states that testing must be conducted within the reasonable, recent past to determine the flash point and boiling point in order to assign proper packing group.  The first step of this process is to perform a distillation test to determine the initial boiling point (IBP).  If the IBP is less than 95 degrees Fahrenheit, the material should be classified as PG I.

If IBP is determined to be greater than 95 F, then the flash point test should be performed to determine whether material should be classified as PG II or PG III.  Flash points determined to be less than 74 F with IBP greater than 95 F are classified as PG II.  Flash points determined greater than 73 F with IBP greater than 95 F are classified as PG III.  Except that the Emergency Order mandates that crude oil which is PG III material must be transported according to requirements of PG I or PG II Crude Oil. 

Why is flash point required?  U.S. DOT states that crude oil might be described as PG III for the purpose of hazardous communication, although packing group information is not part of the Emergency Response Guide. Since crude oil transportation by rail must comply with requirements of PG I or II, distillation should have been sufficient to define packing group, except for the fact that the Emergency Order states the flash point test as required.

In addition to these mandatory tests, shippers are required to perform additional tests frequently enough to ensure proper classification using the nine UN hazard classes in 49CFR parts 171 to 180 as a guide to properly classify their hazardous materials. The DOT Emergency Order requires at a minimum, the testing of vapor pressure, percentage of flammable gases, hydrogen sulfide, sulfur, and corrosivity to steel and aluminum.

Crude oil taken straight from a well is called live crude oil and will likely contain some percentage of light-ends, which are defined as the carbon chain C1 to C5 components including: methane (C1), ethane (C2), propane (C3), butane (C4), and pentane (C5) hydrocarbons.  For safe transport, the C1 to C3 components should be removed in a process called stabilization. This weathered or stabilized material is then called “dead” crude oil which will not actively boil at ambient temperatures.

Aside from the boiling point and flash point tests, the vapor pressure performed by test methods ASTM D6377 or ASTM D323 can identify the presence of high light-end concentrations.  There are EPA tank emission limits and contractual specification that define allowed vapor pressure limits. 

Light-ends compositional analysis of stabilized, dead crude oil can be determined by ASTM D7900 or D6730 modified in accordance with ASTM D7169 X1.  This gives the breakdown of all C1 to C10 hydrocarbons and is useful for modeling. There are no transportation specifications. This detailed hydrocarbon analysis is also useful for merging data with the high-temperature simulated distillation data from ASTM D7169 to give refiners a theoretical rapid yield of the material.

Crude oil may contain hydrogen sulfide, which in high concentrations is a poisonous gas.  It can be determined in the vapor phase by modification of test method ASTM D5705.  Sulfur content, while required by the Emergency Order, poses no immediate hazard and is a characteristic required by the EPA as a combustion property.

The DOT Emergency Order mandates that the crude oil be tested for corrosivity to steel and aluminum in accordance with UN Section 37.  This is to determine whether the material is a Class 8 Corrosive material.  This test takes seven days.  The Order states no mandatory frequency for this test method.  Another test that might be considered in addition to the DOT UN requirement might be the NACE TM0172 test method, which is an industry pipeline standard for corrosivity to steel. It takes just four hours and has the added real-world benefit of rapid mixing with water for its qualification rating protocol.

Crude oil is an expensive commodity that should have quality testing to assure its value.  There are contractual specifications.  Now, due to safety concerns, there are transportation requirements.

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Authors: Scott Blakely,
Laboratory Services Manager
Kesavalu Bagawandoss,
Corporate Technical Director

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