What Caused the Massive Explosion in Tianjin, China?

[StevieTNZ]

Authorities pulled more bodies from a massive blast site in the Chinese port of Tianjin, pushing the death toll to 112 on Sunday as teams scrambled to clear dangerous chemical contamination.
...
Two state-run Chinese news outlets, The Paper and the Southern Metropolis, reported that the warehouse was storing 700 tons of sodium cyanide - 70 times more than it should have been holding at one time, and that authorities were rushing to clean it up.

http://www.nzherald.co.nz/world/news/article.cfm?c_id=2&objectid=11498139

 

[nsaspook]

View attachment 87374
50-75 meters; 10-12 tons; stet.

Even at that size the blast-zone and crater is impressive.
In the large picture those smoking containers are ISO-Tanks.
Dimensions: H: 2,591mm x W: 2,438mm x L: 6,058mm
http://www.dominion-gas.com/argon-isotank/iso-tanks/20ft-iso-acid-tank/

 

[Jon Richfield]

I would imagine that it would be impossible to hide this disaster from the Chinese public.

I don't know which is worse - no regulation or regulation that is ignored. The latter would certainly give the uniformed a false sense of security.

There is no, but NO contest; regulation that is ignored is a disaster waiting to happen, and the disaster includes rendering other regulations impotent through contempt.
Almost as bad are regulations that are unpractical or not understood.

 

[Jon Richfield]

I didn't know about the NH4NO3; I had been badly surprised by alleged estimates of explosions of the order of 21 tonnes of TNT equivalent. That made me sceptical of blebe, gas, & similar explanations, because to assemble enough fuel for that scale of explosion and then to detonate it efficiently is NOT EASY, no matter what the amateurs might think. But Ammonium nitrate might easily be present in hundreds of tonnes quantities, and only a modest efficiency of detonation from the first blast might well have caused the rest.

Now we are hearing about 100 tonne quantities of NaCN as well (though the newscasts ore talking a lot of rot about it). If there really is that much of it there, it just HAS to cause problems; cleaning up that much cannot be a clean matter, and the stuff really is dangerous. 100 tonnes is just about enough to kill every human on Earth, properly administered.

If the figures on the news are to be believed, the death toll so far is minute!

 

[mheslep]

Don't know if this is a valid or WAG calculation but the effects seem to be a lot more than the 'official' 21 T TNT equivalent.

Nice work by Thunderfoot in the video: 300 tons TNT from fireball size, 150 m diameter estimate. He's a working British chemist.

 

[Jon Richfield]

Good grief! If that is accurate it puts it into the same ballpark as the Messines explosion of about 455 tons of ammonal, and that was an engineered explosion, not an industrial accident!

 

[Anders Bruun]

I converted one of the videos to stills -- it makes it "easier" to see what is going on (30 fps frame numbers superimposed):
http://imgur.com/a/ypW2D

(this is the first, smaller explosion).

The fire seems to be pulsating:

http://i.imgur.com/KxPlkj6.png

 

[Astronuc]

Explosion at another chemical plant - update on Tianjin explosion.
http://news.yahoo.com/blast-chinese-chemical-plant-kills-1-050807039.html

On Sunday, the Tianjin city government announced on its microblog account that the death toll in that disaster had been raised to 123. It said 50 people were still missing.

The cause of the Tianjin disaster is under investigation. State media say that the warehouse, which stored sodium cyanide and other dangerous chemicals, was too close to homes and that its operators may have obtained falsified safety approvals.

 

[Astronuc]

China arrests 12 over Tianjin blasts as toll rises
http://news.yahoo.com/china-arrests-12-over-tianjin-blasts-xinhua-032254897.html

Beijing (AFP) - Chinese police have arrested 12 people over giant explosions that killed at least 145 people and devastated a swathe of a Chinese port city, state media said Thursday as prosecutors probe 11 officials for neglecting their duties.
. . . .
The official Xinhua news agency said the dozen formally held include the chairman and senior managers of the firm whose chemical storage facility exploded in the northern city of Tianjin two weeks ago, in the country's highest-profile industrial accident in years.
. . . .
The 12 arrested include owners of Rui Hai International Logistics who were shown on state television last week, when they were already being held by police, "confessing" to using government connections to obtain safety permits.
. . . .