Friday, November 14, 2014

Testing travails for shale crude on rail

I have been following the shale oil on rail story a little. I don't know why, but I find it (and the Wall Street Journal's coverage of it very interesting), especially since it hinges on accurate chemical testing: 
Regulators set to decide on crude-by-rail shipping rules are relying on testing methods that may understate the explosive risk of the crude, according to a growing chorus of industry and Canadian officials. 
The tests’ accuracy is central to addressing the safety of growing crude-by-rail shipments across the continent: whether Bakken crude contains potentially dangerous levels of dissolved gases. Several trains carrying Bakken crude have exploded after derailing, including a fiery accident last year that killed 47 people in a small town in Quebec. 
...The U.S. government recently tested the same North Dakota crude using both the older and newer methods to compare the results.
Testing crude after the light ends have escaped is like popping open a bottle of soda and trying to determine how fizzy it was in the bottle, said Bob Falkiner, refinery director at a Canadian crude-quality association that is calling attention to problems with existing studies. “If your goal is to measure the amount of carbon dioxide in a can of soda pop, clearly you can’t pour it into an open beaker because the very thing you want to test for will be gone,” said Mr. Falkiner, an engineer at Exxon Mobil Corp. XOM -1.01%  ’s Canadian subsidiary.
The testing controversy centers on how to determine vapor pressure, a measure of how quickly a liquid fuel evaporates and emits gases. Traditionally, the industry has relied on Reid Vapor Pressure, a decades-old methodology but one that doesn’t require sealed or pressurized containers to collect or test crude samples. 
“For some of the production there are some differences that they wouldn’t have picked up on unless they sampled it properly,” said Andre Lemieux, a board member at the Canadian crude-quality association. In October, Ottawa acted on the recommendation of Mr. Lemieux’s group and said it would analyze how crude reacts in a sealed cylinder to better understand how it reacts during transport in a tank car. 
Canada’s transport ministry doesn’t typically test oil or other potentially hazardous products, but decided to run a series of tests following up on a Transportation Safety Board investigation of crude involved in the Quebec train disaster. The study will look at 80 samples of Canadian crudes and will incorporate sealed and pressurized cylinders.
“We’ve identified it as probably being for our purposes the most accurate test to make sure we’re not losing any light ends” said Patrick Juneau, a Transport Canada engineering research officer in charge of the tests. “The science on this is evolving. Where we were a year ago or five years ago is different from today,” he said. 
Under normal conditions, these light ends can boil out of the crude, creating a volatile head on the crude inside the tank car that can increase the risk and magnitude of an explosion. Many light oils contain elevated levels of highly volatile gases like butane and propane, but where they are highest-such as in the Eagle Ford shale in Texas—crude is routinely stabilized to remove them. As The Wall Street Journal reported, producers in the Bakken have rejected calls so far to stabilize the crude, citing studies such as those by the North Dakota Petroleum Council and the American Fuel and Petrochemical Manufacturers. Both concluded that Bakken crude wasn’t more volatile than other crude oils in the U.S. 
The lead author of the North Dakota Petroleum Council study defended the work, saying his technique was more than adequate for determining the amount of dissolved gases in crude. “The results would be no different” using sealed containers, said John Auers. “We used the standard methodology used for years.” 
There is no information about how samples were collected in the AFPM study, but the author, Frits Wybenga said there are no data to suggest the commonly used test is inadequate. “Nobody has demonstrated this is a problem,” he said. 
A scientist with North America’s leading testing firm said in a February presentation that measurement of volatility in crudes “can be easily affected by the loss of light end materials during sampling process.” And a study conducted under more stringent conditions by the U.S. government did find more volatile compounds present in Bakken crude. The government study was the only one that tested a variety of companies; other studies relied on companies volunteering to be tested....
I have no doubts that there are more volatile gases in crude from fracking, but I suppose that it's all about data and testing methods here. Lots of money is riding on which testing method needs to be used.

(How would they get rid of the gases anyway? Purge/sparge the tanks with nitrogen? Pull vacuum on the railcars for 20 minutes (oh man, the mess.))

UPDATE: And this post appears to be overtaken by events -- from this morning's physical copy of the WSJ (emphasis mine):
North Dakota plans unprecedented steps to ensure crude pumped from the state’s Bakken Shale oil producing region is safe enough to be loaded into railroad tank cars and sent across the country. In the first major move by regulators to address the role of gaseous, volatile crude in railroad accidents, the North Dakota Industrial Commission, which regulates energy production in the state, said it would require Bakken Shale well operators to strip gases from crudes that show high vapor pressures. 
“We believe the vast majority of our Bakken oil will fall well below the standard,” Lynn Helms, director of the state’s Department of Mineral Resources, said at a news conference. The proposed state rule will require all operators to run crude oil through equipment that heats up the crude and forces out gases from the liquid. An estimated 15% of current producers without such equipment will have to submit quarterly test results showing their wells don’t exceed the state’s proposed 13.7 pounds a square inch vapor pressure limit, Mr. Helms said.... 
...A representative for the North Dakota Petroleum Council, an industry lobbying group, criticized the proposed rules for “micromanaging the industry,” and said they could lead to unintended consequences such as increased burning of excess natural gas at well sites.
The proposal also would prohibit blending condensate or natural gas liquids back into crude and require rail loading terminals to inform state regulators of any oil received for shipment exceeding the vapor pressure limits, Mr. Helms said...
Huh. Well, ND crude-by-rail just got a little more expensive. Good for whoever is selling them the heating equipment, maybe.


1 comment:

  1. Don't even think about pulling a vacuum in a standard rail tank car. You might as well use a beer can.

    I responded years ago to an LPG tank car which the railroad had "abandoned" on a siding in downtown Wilmington. It had been exposed to a fire (elsewhere), the relief valve had opened then closed when the tank cooled. The weather cooled considerably and we were left with a tank car about half full of LPG which looked like the Jolly Green Giant had squeezed.

    I happened to be the state response team leader that week and had a heck of a time getting it moved to a less populated area and offloaded. Had to do the offloading myself as no one wanted to take the liability (along with the possibility of being sent into a low earth orbit).

    I am sure the ND Petroleum people will try to convince everyone that there is no special hazard (yeah, right). It would be a lot better for all concerned IMHO if the fire research folks at NIST in Maryland would take this up.

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