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The small horizontal tanks directly to the south of the barn are the anhydrous tanks.

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You sure?

I was thinking it was that larger tank farther North.

what would be stored in that large silo looking structure to very north?



[This message has been edited by BarnacleScraper (edited 4/18/2013 3:03p).]

Yeah, I'm sure on the anhydrous tanks. The bins to the north are grain bins. The vertical white tanks are for liquid fertilizer storage.

Google Street View really gives a little perspective....

the apartments are right up on the plant, and the nursing home was on the other side of the apartments and across the street. middle school isn't far away at all.

Additionally, all of those little white horizontal tanks at the bottom are the anhydrous trailers farmers use when applying the anhydrous to their fields.

[This message has been edited by AgEng06 (edited 4/18/2013 3:05p).]

what's in the large cylindrical structure.

Also, is there a combustability for grain bins akin to grain silos?

Could be anything dry, BS.

I read in one of the two threads that this was a distribution place, not a manufacturing, so they could have been distributing anything there.

Possible that they are silos of fertilizer to load up in rail cars or truck trailers. Those would not have seen water and become volatile. Don't know if they would add to the explosion either. One of the ChemE's would need to answer that one.

Silos with dry good blow due to the static electricity buildup.

This is beginning to appear as though all the right ingredients were in place at all the wrong times.

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Yeah, I'm sure on the anhydrous tanks

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Well, eff me.

Gordo_14. I apologize for jumping on your case, BUT you're still wrong in that it was not the NH3 tanks that blew.

Grain.

The combustion risk in grain elevators is due to the moving grain and grain dust being entrained in the air. There wouldn't be as much of a problem in a storage bin because of the lack of agitation, except during loading operations.

[This message has been edited by AgEng06 (edited 4/18/2013 3:09p).]

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This is beginning to appear as though all the right ingredients were in place at all the wrong times.

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This is pretty much how all large scale industrial accidents happen now.

I've seen investigation reports, been part of an incident inquiry, and sat through HAZOPs. So many factors had to line up perfectly, but it always boils down to human failure at some point that allowed those factors.


Edit: though, we still don't know what caused the initial fire in this. In reality, it was the addition of water that exacerbated the situation to a bomb. The guys were just there trying to do their job, and they probably weren't fully aware of the danger.

[This message has been edited by CDUB98 (edited 4/18/2013 3:12p).]

My thoughts. Farmers can use/store anhydrous ammonia (AA) on their fields. Directly spray it into the soils to increase nitrogen content.

One of three things could have had the AN in it.




If the tanks in the middle are concerned for catching fire/becoming a BLEVE/fire surroudning them and the barn to the NW of them has AN, water could have been sprayed into it. Mix with some air, a little more heat and it can go boom.

~egon

[This message has been edited by Dr. Doctor (edited 4/18/2013 3:12p).]

Has there been any more news released (facts, hopefully) since this morning? Anything I can find is all very old info.

btw, this link is still saying anhydrous

http://www.newschannel10.com/story/22010772/authorities-on-scene-of-fatal-explosion-near-waco

Dr:
The silo to the north houses grain. The AN is in the silver barn. The while building to the east is the office/shop/chemical storage. There is a scale on the east side of the white building that is visible.

You can see the loadout conveyor on the east side of the AN barn if you look closely. That's where they would load farmers' hoppers for use in their field.

[This message has been edited by AgEng06 (edited 4/18/2013 3:16p).]

50,000 pounds (I think that is the amount I read) of AN would require about what 40 cubic yards of storage?

Anyone of those buildings could contain that correct?

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it always boils down to human failure at some point that allowed those factors.

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there's no grand scheme of design (relief, process alarms, safety interlocks, etc) that can substitute for an experienced, competent operator

those guys are worth their weight in gold

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To get enough water on AN would actually cause it to cool off and freeze (instant ice packs are a small amount of AN in a big bag of water). But that would be, with a SWAG, about a 10-1 ratio of water to AN. So if there are TONS of AN in the barn, you need to get 10x or more tons of water into the barn. Quickly.

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So 50,000 lbs of AN would need 60,000 gallons of water (if my math is correct)?

i get your point but i disagree. safety in design always trumps human. even the best intentions or knowledge can make mistakes.

edit - for superdave

[This message has been edited by sts7049 (edited 4/18/2013 3:23p).]

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The entire town has been evacuated due to the lingering risks associated with the anhydrous ammonia in the area

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AN was not the explosive. What they are worried about is AN leaking from tanks and it is very toxic.

JTA, I get about 62.5k but close enough.

sts, humans override safety items all the time, thus allowing the wrong factors to line up at the right time.

Design it as safe as possible, always, but humans eff it up either due to complacency or outright negligence.

62.5k gallons in pretty much an instant.

Ain't happening.

Terrible horrible situation.

Imagine how much worse this could be if it occurred at 2pm when those schools would have been full of kids.

that would be the amount to cool it right CDUB, not to ignite it?

Ask the Agronomist(TM) says ...
I'd be surprised if ammonium nitrate had anything to do with it. There is actually very little granular ammonium nitrate used these days due to expense. You will find it in UAN solutions, but not so much as dry granular.

Right. Any amount of water makes in much more volatile, until you reach enough to cool it.

If I understand DrDr correctly, yes.

B-1, wasn't the amount also lowered after the OKC bombing?

yeah, that's not very feasible then

Tighter regulated, for sure.

There are several types of granular fertilizer housed in that silver barn, but ammonium nitrate is among them. The number I heard was that there was 50,000 lbs of ammonium nitrate (henceforth, AN) present.

are they stored together or separate?

If they did lots of custom blending, they each had their own open bin

I'm sticking with AgEng06, though. There was something in that barn that blew, and AN makes the most sense.