While 540,000 lbs of NH4NO3 have been reported, the pictures of what remains of the plant seem to indicate a large amount of something with less power than ammonium nitrate...270 tons
of which should have pulverized the plant to shrapnel and left a notable crater...
"You're going to be all right, kid...Everything's under control." - Yossarian, to Snowden
Not exactly. All of it would have to come to the decomposition temp at once. I'm sure a sizable quantity reached that temp but not all of it at the
same time.
Here's a new video. It seems there was really a ton of stupid people around the plant.
This might be from the other side, and you can see there were several bursts in a very short time, probably resulting from pressure tank ruptures
induced by the main blast.
It seems likely that the fire over-pressured and over-heated the liquid ammonia tanks, at least one of which then failed catastrophically, creating a
cloud of flammable vapors which likely reacted with the hot ammonium nitrate to create a larger deflagration/explosion, which likely initiated the
other tanks of ammonium nitrate to explode. All of this might have happened in a very short time, creating what appears to be one large explosion,
but is likely several explosions of growing size. Getting the exact order of which went first will take a while, but might be determined eventually.
But certainly there was enough ammonium nitrate (100+ tons) and anhydrous ammonia (10,000's of gallons) to create a large explosion under the worst
case scenario. I counted at least 3 silos of AN and 3 or more large tanks of liquid ammonia. Anhydrous likely does mean liquid ammonia. And
ammonium nitrate slurry in water is used in blasting, so while the solution may be safe, ammonium nitrate as a slurry of prills in water can explode
under the right conditions, especially if a fuel is present.
The combination of ammonium nitrate and ammonia would certainly be able to create an explosion, as for each ammonia that is oxidized, you get 3
molecules of water and 0.5 N2, so that creates a very large amount of gas, and with AN, it would be:
NH3 + NH4NO3 ---> 1.5 N2 + 3 H20 + 1/2 H2
So from a liquid and a solid, you generate roughly 5 moles of a gas, plus a large amount of heat. That would certainly be enough gas to create a
large explosion.
The combination of ammonium nitrate and ammonia would certainly be able to create an explosion, as for each ammonia that is oxidized, you get 3
molecules of water and 0.5 N2, so that creates a very large amount of gas, and with AN, it would be:
NH3 + NH4NO3 ---> 1.5 N2 + 3 H20 + 1/2 H2
I think it would be more likely to give 2 NH3 + 3 NH4NO3 --> 4 N2 + 9 H2O
My mind rebels at seeing hydrogen generated from a conflagration.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
Just looking at the satelite picture I conclude the following:
1. There was no manufacturing, or likely even blending of ferilizers (not enough tanks, pipes, pumps, etc). The "plant" looks to be only for storage
and distribution.
2. There are many smaller anhydrous ammonia tanks likely for use on location in a farmer's field.
3. There are quite a few larger anhydrous ammonia tanks for truck transport on the highway to other distributors.
4. The big gray silos look like they are for storage and distribution of dry particle fertilizers, likely NH4NO3 prills. One silo looks like it can
receive product from the nearby railroad.
The large circular structure with all the small white rectangles neatly arrayed in it puzzles me. Anybody know what that is?
Why do we think that anhydrous ammonia had anything to do with the explosion other than through over-pressurization of the tanks? Wouldn't
over-heated NH4NO3 be enough to cause the explosion in and of itself?
NH4NO3 + heat --> N2O + 2H2O (Wiki)
Rules? Hell, there are no rules. We're tryin' to get sumpin' done here. - Thomas Edison
A few of my colleagues and I were talking about this. We came to the conclusion that the coverage of the ammonia was a bit like them saying "This
plant with 250 tones of explosives and a lithium battery exploded- but, because we have heard they use lithium to make meth it must be devilishly
dangerous so we will blame it."
(And these are my colleagues who deal with risk assessments for hazardous processes and me, whose jobs include looking at what should or shouldn't be
built near such factories)
Ammonium nitrate factories blow up from time to time- usually due to a fire- occasionally due to outright stupidity.
I still have not seen a better photo of the actual blast site than the one I posted. Other photos including aerials seem to be rather deliberately
just off to one side or low-res. Don't hear much except for the paramedic who has been silenced by prosecution after talking, after being fired
immediately after talking...It's said that the manager of the nitrate operation was a fireman and quite aware of what they including 2 civilians were
getting in to, and all of them were found within yards of the crater. The wisdom of going anywhere near it much less putting water on it seems yet to
come up. IIRC people predicted the brick wall for the CSB from the beginning. I wonder if they actually have access to the US Marshals.
-------------------------------------------
WACO, Texas May 22, 2013 (AP)
Federal agents and the state fire marshal have effectively barred a federal safety panel from the site of a Texas fertilizer plant blast that killed
15 people and injured about 200 others, hampering its investigation, the panel's chairman said.
In a May 17 letter to Sen. Barbara Boxer, U.S. Chemical Safety Board Chairman Rafael Moure-Eraso asked the California Democrat to help the board
obtain evidence under control of the Bureau of Alcohol, Tobacco, Firearms and Explosives that he contends is essential to the board's investigation,
the Waco Tribune-Herald and Austin American-Statesman reported.
"To date, the CSB has experienced significant obstacles that potentially compromise and delay our ability to complete the 'comprehensive
investigation' that you have rightly demanded, and that we would very much like to produce," he wrote to Boxer. The chairwoman of the Senate Committee
on Environment and Public Works has said she planned to hold hearings into the April 17 West Fertilizer explosion.
A criminal investigation "comes with certain sensitivities. You need to keep it to law enforcement only," Robert Champion, ATF special agent in charge
of the investigation told the American-Statesman. He also said the decision to bar the CSB from the site was made by the State Fire Marshal's Office.
Fire Marshal's Office spokeswoman Rachel Moreno said the CSB was kept out because criminal investigators were executing search warrants.
"We have to protect evidence," she told the American-Statesman. "We need to have one report, one set of interviews; it all has to be clear cut."
Messages left by The Associated Press with ATF and the State Fire Marshal's Office were not returned Tuesday night. However, a Boxer spokeswoman said
the senator had asked the agencies to respond as quickly as possible to her concerns regarding the issues raised in the letter.
In an April 30 statement, Boxer said she "cannot rest until we get to the bottom of what caused the disaster" in West and that she wants to make sure
such facilities are complying with chemical safety laws.
In his letter, Moure-Eraso said the board sent 18 investigators and other experts to West within 24 hours of the blast. At the same time, ATF "assumed
essential exclusive control of the incident site" with the State Fire Marshal's Office, he wrote.
"These criminal investigators have exercised exclusive control of the site for a full one-month period ... and have altered or removed almost all
relevant physical evidence at the site," he wrote.
ATF and the State Fire Marshal's Office "consistently expressed the position that CSB was not permitted to conduct separate interviews, prepare expert
analysis or author its own independent report," he wrote. ATF and the state fire marshal "state that because in their view this was exclusively a
criminal investigation, there could be only one version of what occurred and one report."
On May 16, representatives of the State Fire Marshal's Office announced that the joint criminal investigation left the cause of a fire precipitating
the blast as "undetermined."
Investigators narrowed the number of possible causes to three: a problem with one of the plant's electrical systems, a battery-powered golf cart and a
criminal act. However, they could not say with certainty what caused the fire that ignited stored ammonium nitrate, said Kelly Kistner, the assistant
state fire marshal.
"You're going to be all right, kid...Everything's under control." - Yossarian, to Snowden
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