Wednesday, April 3, 2019

Tank Car Safety, "thermally treat" a LPG plus diesel fuel derailment

I've already written some notes on tank car safety: one and two. But I feel this information on how to cleanup a derailment of flammable tank cars that did not fail during the derailment was worth its own set of notes.

I've already learned that "energetic felling" is a euphemism for blowing up ("controlled demolition of") a bridge. With this UP derailment of 23 cars that included nine LPG and two diesel fuel tank cars, I've learned that "thermally treat" or "thermal solution" is a euphemism for blowing a hole in a tank car and letting the product burn to exhaustion. Then you dispose of the tank cars. I would presume they are treated as scrap metal.

I start these notes at the end of the timeline with a video of the resulting fire.

(new window)    source: DesertNews    It appears they explode a hole in each LPG tank and the liquid flashing to a gas out of the hole burns as a bright yellow jet. The darker clouds are probably the diesel fuel burning on the ground.

A Flickr photo of what the cars looked like after the "thermal treatment." (source)

Following are the postings about this accident in the order that I saw them.

Second photo, cropped, from KSL
A Union Pacific train derailment of 23 cars released an unknown quantity of propane after one car overturned about six to eight miles south of Eureka, prompting the response of multiple emergency crews Saturday, March 30, 2019. (Photo: John Wilson, KSL TV)
[There were no injuries.]

A later report on this accident.
Second photo in Gallery from Fox23now, Courtesy of Sherrie Kay (a nearby camper)
"The controlled detonation involved eleven cars, nine full of propane and two with biodiesel fuel."
David Brann The propane is likely LP gas, which is held liquid at ambient temperature by being under pressure. If the pressure is relieved, by rupture of the tank car, the gas will flash to vapor. In the presence of an ignition source, the result is a Boiling Liquid Expanding Vapor Explosion, or BLEVE, which is a truly spectacular event. I have never witnessed one in person, only seen videos, which were sufficient to make me glad that I was not around when one went off. If they plan to create a BLEVE intentionally, I hope they stand back.
Patrick Quinn David Brann a BLEVE results from a pressurized vessel failure due to impingement of heat on the tank and the liquid level unable to cool the area of impingement and the tank fails while under pressure , if they ruptured the tank to burn off the product it won’t result in a BLEVE.
Chris Gosnell We always called them a Blast Leveling Everything Very Effectively. But burning the gas off wont be a bleve. It will be a great fire but the boiling part is what makes them so spectacular. Basically tank is pressurized a lot by the boiling and releases all of its contents at once when the metals fatigue limit is reached. A smallish hole could burn for a long time and not burst.
[The article is not real clear, but it sounds like they removed four cars carrying monoammonium phosphate fertilizer and some tankers carrying phosphoric acid before they torched the propane and diesel fuel tank cars.]

(new window)     source: DesertNews 

No comments:

Post a Comment