Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
 Pages:  1  2    4
Author: Subject: What did actually explode in Tianjin ?
careysub
International Hazard
*****




Posts: 1339
Registered: 4-8-2014
Location: Coastal Sage Scrub Biome
Member Is Offline

Mood: Lowest quantum state

[*] posted on 10-9-2015 at 10:22


Quote: Originally posted by James Ikanov  
FAE might be a strong word.

Basically what I think happened was that a flammable vapor (either the liquid natural gas or vapors from toluene, acetone, or MEK spread across the floor) was ignited, and that the fire that resulted was boosted by all the fun oxidizers present at the site plus a certain amount of oxygen in the air after a few seconds of being heated rather vigorously enough to decompose.


There was first a huge raging fire before any explosions. An FAE requires a combustible gas dispersal in the absence of ignition sources, until the fuel cloud is established. This cannot happen in the middle of a inferno.

A real case of an FAE effect in an accident is the Los Alfaques, Spain disaster:
https://en.wikipedia.org/wiki/Los_Alfaques_disaster
(which is often inaccurately described using another buzz-word BLEVE - it was clearly not a BLEVE). The propylene had time to form a large pancake cloud before it found an ignition source, then an instantaneous explosion ensued.

Sure, lots of stuff burned in the warehouse, before, during and after the explosions.

(I partly blame Hollywood which like to pass off burning gasoline fireballs as "explosions" for confusing people's minds about this.)
View user's profile View All Posts By User
James Ikanov
Hazard to Self
**




Posts: 81
Registered: 12-7-2015
Location: Alaska
Member Is Offline

Mood: Zen

[*] posted on 10-9-2015 at 11:53


Could a similar effect not have been achieved by pressurized containers of liquefied natural gas, or if some flammable liquid was dispersed by the smaller initial explosions?

(just curious. I appear to be quite incorrect in my initial terminology.)

[Edited on 10-9-2015 by James Ikanov]
View user's profile View All Posts By User
aga
Forum Drunkard
*****




Posts: 7030
Registered: 25-3-2014
Member Is Offline


[*] posted on 10-9-2015 at 11:58


Quote: Originally posted by careysub  
I partly blame Hollywood which like to pass off burning gasoline fireballs as "explosions" for confusing people's minds about this.

What minds ? Are there any left ?




View user's profile View All Posts By User
careysub
International Hazard
*****




Posts: 1339
Registered: 4-8-2014
Location: Coastal Sage Scrub Biome
Member Is Offline

Mood: Lowest quantum state

[*] posted on 10-9-2015 at 12:55


Quote: Originally posted by James Ikanov  
Could a similar effect not have been achieved by pressurized containers of liquefied natural gas


What you get when that happens is, first, a real BLEVE (boiling liquid expanding vapor explosion - a strictly physical phenomenon), then milliseconds later a flash fire ball when the explosively expanding gas cloud ignites.

Quote:
if some flammable liquid was dispersed by the smaller initial explosions?


This would generally be a fireball, without a real explosion. But flash combustion can be quite destructive - the radiant heat can incinerate things quite some distance away* - it just doesn't produce a damaging pressure wave.

A very short course in "explosionology":
* Most generally an "explosion" is a sudden release of energy that produces a damaging pressure wave (blast) - bursting boilers, pressurized gas tanks, volcanic pressure releases, and the ignition of explosives are all well know causes.
* With chemical reactions are the source of the energy release there are two classes of explosions: detonation and deflagration.
* A detonation is a particular type of explosive reaction only found in high explosives (by definition). It is when a shock wave traveling through the explosive triggers the energy release, thus a large share of the total release ends up in a single intense shock front. The pressures produced are very high and these are the most destructive. A genuine FAE creates a detonating gas cloud.
* A deflagration is simply a very rapid burn, all low explosives (black powder/gun powder) explode in this way. There is no sharp distinction between "just a deflagration" or a "deflagrating explosion", it depends on how fast is fast. If there is a damaging pressure wave, then it is an explosions, otherwise no. Occasionally someone will claim that only detonations are real explosions, but people were blowing stuff up with gun powder for centuries before the advent of high explosives.

Rapid incinerations of energetic materials often has an autocatalytic character - the heat released by a deflagration causes the combustion to accelerate, transitioning into a (low) explosion, and perhaps then even to a detonation (high) explosion if the material is capable of supporting it (ammonium nitrate is a chemical that can). So in a warehouse fire you can get a lot different types of events occurring in sequence, or together.

*Years ago there was a natural gas pipeline fire in Mexico City that killed people hundreds of yards away from the intense heat of the giant flame. I tried Googling it, but Mexico has lots of gas-related disasters so I was not able to pick it out of all the other stories.
View user's profile View All Posts By User
Bert
Super Administrator
*********




Posts: 2745
Registered: 12-3-2004
Member Is Offline

Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".

[*] posted on 10-9-2015 at 19:27


"Calcium metal alloy"

That could give a nice meteor like effect, burning on the way back down... The Sodium seems to have been a mistake or typo based on "Sodium nitrate".

Hope the Chinese take an even strain on safety in the near future. Too often they over react after an incident/accident, stop any and all HazMat export, everything stops moving that has a scary name or a menacing sounding UN classification- And then 3 or 4 months later, news moves on to a new & different cause célèbre- And suddenly it's all back to business as usual.




Rapopart’s Rules for critical commentary:

1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.

Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).

View user's profile View All Posts By User
Mush
International Hazard
*****




Posts: 599
Registered: 27-12-2008
Member Is Offline

Mood: No Mood

[*] posted on 22-9-2015 at 13:02


I think 21 tonnes of TNT equivalent is well under estimated. Just compare to these ones:

500 t TNT
https://www.youtube.com/watch?v=hkoBwFYitlU

100 t TNT
https://www.youtube.com/watch?v=KUu7yPG52J8

50 t TNT
https://www.youtube.com/watch?v=bIQr62lZbsM
View user's profile View All Posts By User
aga
Forum Drunkard
*****




Posts: 7030
Registered: 25-3-2014
Member Is Offline


[*] posted on 22-9-2015 at 13:36


Nobody cares.

Old news now, and nobody will ever Know what exploded.

Probably not even the warehouse owner, Chinese investigators.

My guess is pot nitrate, ammonium nitrate and arduino clones.

The sparkly bits were once touch screen TFTs or magnesium Barbie Doll prosthetics.

Time to move on.




View user's profile View All Posts By User
j_sum1
Administrator
********




Posts: 5689
Registered: 4-10-2014
Location: Unmoved
Member Is Offline

Mood: juggling juggling juggling

[*] posted on 14-2-2016 at 16:38


Update
http://cen.acs.org/articles/94/web/2016/02/Chinese-Investiga...




View user's profile View All Posts By User
Detonationology
National Hazard
****




Posts: 362
Registered: 5-5-2015
Location: Deep South
Member Is Offline

Mood: Electrophillic

[*] posted on 14-2-2016 at 17:03


Nitrocellulose? Who would have guessed? No mention of sodium or any metals, so I wonder what those streaks across the sky were. I can't imagine ammonium nitrate producing such a sight...



“There are no differences but differences of degree between different degrees of difference and no difference.” ― William James
View user's profile View All Posts By User
j_sum1
Administrator
********




Posts: 5689
Registered: 4-10-2014
Location: Unmoved
Member Is Offline

Mood: juggling juggling juggling

[*] posted on 14-2-2016 at 17:22


I am going to postulate that some of the details have been glossed over either in the report or in the article I linked. I think it focuses on the explosion itself, its initiation and primary components. Not mentioned are the stocks of other chemicals which went up as a consequence.

It also seems to down-play the environmental damage caused. Now, it may be that there was little or no damage to the waterways and few toxins released into the air. But somehow I doubt it. This notion seems at odds with early reports (and photos of acres of dead fish). It also seems at odds with what one would expect from such an event.

So, as often happens, we may never know the full truth. However, to have this much from official sources is at least better than nothing.

And this would not be the world's first large-scale AN disaster.




View user's profile View All Posts By User
morganbw
International Hazard
*****




Posts: 561
Registered: 23-11-2014
Member Is Offline

Mood: No Mood

[*] posted on 15-2-2016 at 13:41


Quote: Originally posted by j_sum1  
I am going to postulate that some of the details have been glossed over either in the report or in the article I linked. I think it focuses on the explosion itself, its initiation and primary components. Not mentioned are the stocks of other chemicals which went up as a consequence.

It also seems to down-play the environmental damage caused. Now, it may be that there was little or no damage to the waterways and few toxins released into the air. But somehow I doubt it. This notion seems at odds with early reports (and photos of acres of dead fish). It also seems at odds with what one would expect from such an event.

So, as often happens, we may never know the full truth. However, to have this much from official sources is at least better than nothing.

And this would not be the world's first large-scale AN disaster.


You are exactly right. The nitrates have a history of being bad actors under certain conditions. There has been a lot of good thoughts/theorys in this thread. I do not know what the initiator was but I feel the nitrates were involved in the booms. I do know that acetylene with the proper air mixtures is more than a fireball.
View user's profile View All Posts By User
Bert
Super Administrator
*********




Posts: 2745
Registered: 12-3-2004
Member Is Offline

Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".

[*] posted on 15-2-2016 at 14:12


I do not think the exact truth of the matter as far as cause of the triggering event will become known. Business records of materials storage and handling along many people who would truly know first hand were lost in the incident-

The best that can be hoped for is that the local authorities having jurisdiction learned a lot about the many types of Hazmat passing through their areas, general dangerous goods handling and storage best practices, along with developing the political will to ensure their bulk Hazmat facilities are better run in the future.

But it's been my experience of China (and many other places) that when public outcry dies down, businesses usually go right back to making the most money with the least cost, regardless of the danger to employees and neighbors. Then the NEXT incident shows how little was actually done to change exposure to the hazard...




Rapopart’s Rules for critical commentary:

1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.

Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).

View user's profile View All Posts By User
Herr Haber
International Hazard
*****




Posts: 1054
Registered: 29-1-2016
Member Is Offline

Mood: No Mood

[*] posted on 15-2-2016 at 22:48


Quote: Originally posted by Bert  

I have seen a fair number of sensitized ammonium nitrate explosives shot. Water vapor condenses and leaves a white cloud. Aluminum as a sensitizer increases the appearance of a white cloud.


I will answer this. You are talking about sensitized NH4NO3 detonated on purpose for maximum effect.
I was in Toulouse on the 21 September just 10 days after 9/11.
You can bet paranoia was at it's peak.

I could tell you about the paint that had Fallen from my roof to make it look as if it had snowed in the room. I could tell you about the broken Windows several kilometers away and PVC Windows blinders that where either shattered or unworkable closer to the blast (like mine).

What was in the sky that day clearly wasnt a white cloud of smoke. It was "goose shit" colored. The presence of several Nitrogen oxydes was very obvious to the throat and to the eyes.
Not brick red, but brownish/tan or whatever you want to call it. I cant even agree with colors in my own language with other people...

As for C2H2 being the major cause of the explosion this is ludicrous. It would imply a perfect mix of so much gas and air that I cant even imagine happening in the real world while other explosions and fires are raging.
And believe me: I've seen acetylen/air explosions. I use carbide lamps for caving and strolling through quarries because of the fantastic light they give (there's no gas with a highter C content).
Some of the lamps that we use are 60 or 70 years old and a bit of gas sometimes makes it to the water reserve. I've seen a lot of people approaching a flame to see the water level ending up with the smell of burnt hair (me included).
Sometimes, the flame from the lamp is enough to light the air/gas mix in the water reserve. That's also "funny".
It's the result of the tubing getting porous after such a long time, too much pressure and C2H2 "oozing" into the water reserve.

I'd gladly show some pictures if some of you think this is worthy of another thread.
A friend of mine even got himself a "cannon" to scare birds off fields. Water goes down, pressure builds up and a piezo-igniter ignites the mix at regular intervals.
Old tech ;)

[Edited on 16-2-2016 by Herr Haber]

Edit(woelen): Fixed quote formatting tags so that message looks sane again.

[Edited on 16-2-16 by woelen]
View user's profile View All Posts By User
PHILOU Zrealone
International Hazard
*****




Posts: 2880
Registered: 20-5-2002
Location: Brussel
Member Is Offline

Mood: Bis-diazo-dinitro-hydroquinonic

[*] posted on 16-2-2016 at 03:11


Quote: Originally posted by Herr Haber  

I will answer this. You are talking about sensitized NH4NO3 detonated on purpose for maximum effect.
I was in Toulouse on the 21 September just 10 days after 9/11.
You can bet paranoia was at it's peak.

Oh un français toulousain :D ...
Bienvenue Monsieur! Wilkom, meine Herr! ;)
So you were in first raw to see AZF Toulouse blow...very interesting. I'm curious what are your speculations about what happened there and then. Did you see thunder in bals coming out of the ground prior to the blast? Did you eard two explosions at interval? There is a theory about a strange electrical blast in the underground of the SNPE a few km away prior to the AZF plant explosion and magnetic monopole could be involved...just like what happens when big earthquake happens in oil rich soil building very strong electrostatic potential and ground triboelectricity...this seems to have been cause of weapon depots explosions in Romania.


Quote: Originally posted by Herr Haber  

I could tell you about the paint that had Fallen from my roof to make it look as if it had snowed in the room. I could tell you about the broken Windows several kilometers away and PVC Windows blinders that where either shattered or unworkable closer to the blast (like mine).

Must have been horrible and frightening.

Quote: Originally posted by Herr Haber  

What was in the sky that day clearly wasnt a white cloud of smoke. It was "goose shit" colored. The presence of several Nitrogen oxydes was very obvious to the throat and to the eyes.
Not brick red, but brownish/tan or whatever you want to call it. I cant even agree with colors in my own language with other people...

Yes we know, in such blast, not only the pure compounds do explode but also the all infrastructure (plastics, wood, stone, metals, oils) for a very special shade or colourfull panaché.

Quote: Originally posted by Herr Haber  

As for C2H2 being the major cause of the explosion this is ludicrous. It would imply a perfect mix of so much gas and air that I cant even imagine happening in the real world while other explosions and fires are raging.
And believe me: I've seen acetylen/air explosions. I use carbide lamps for caving and strolling through quarries because of the fantastic light they give (there's no gas with a highter C content).
Some of the lamps that we use are 60 or 70 years old and a bit of gas sometimes makes it to the water reserve. I've seen a lot of people approaching a flame to see the water level ending up with the smell of burnt hair (me included).
Sometimes, the flame from the lamp is enough to light the air/gas mix in the water reserve. That's also "funny".
It's the result of the tubing getting porous after such a long time, too much pressure and C2H2 "oozing" into the water reserve.

I'd gladly show some pictures if some of you think this is worthy of another thread.
A friend of mine even got himself a "cannon" to scare birds off fields. Water goes down, pressure builds up and a piezo-igniter ignites the mix at regular intervals.
Old tech ;)

[Edited on 16-2-2016 by Herr Haber]

Acetylen is one of those rare gases that is detonable without air if pressurized and that display very large explosion limit...
This means it can burn, deflagrate or detonate in almost all % mixture with air...no need for perfect OB.
This explains the old tech carbide canon works so wel...

[Edited on 16-2-2016 by PHILOU Zrealone]




PH Z (PHILOU Zrealone)

"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
View user's profile View All Posts By User
hissingnoise
International Hazard
*****




Posts: 3940
Registered: 26-12-2002
Member Is Offline

Mood: Pulverulescent!

[*] posted on 16-2-2016 at 06:31


Quote:
Acetylene is one of those rare gases that is detonable without air if pressurized and that display very large explosion limit...
This means it can burn, deflagrate or detonate in almost all % mixture with air...no need for perfect OB.

And its just ever so slightly lighter than nitrogen, allowing it to quickly mix with air . . . ?

View user's profile View All Posts By User
PHILOU Zrealone
International Hazard
*****




Posts: 2880
Registered: 20-5-2002
Location: Brussel
Member Is Offline

Mood: Bis-diazo-dinitro-hydroquinonic

[*] posted on 16-2-2016 at 13:41


Quote: Originally posted by hissingnoise  
Quote:
Acetylene is one of those rare gases that is detonable without air if pressurized and that display very large explosion limit...
This means it can burn, deflagrate or detonate in almost all % mixture with air...no need for perfect OB.

And its just ever so slightly lighter than nitrogen, allowing it to quickly mix with air . . . ?


True!
H-C#C-H --> +/- 26 g/mol (= 26g /22.41 L at STP)
N#N --> +/- 28 g/mol (= 28g /22.41 L at STP)
O=O --> +/- 32 g/mol (= 32g /22.41 L at STP)




PH Z (PHILOU Zrealone)

"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
View user's profile View All Posts By User
Herr Haber
International Hazard
*****




Posts: 1054
Registered: 29-1-2016
Member Is Offline

Mood: No Mood

[*] posted on 16-2-2016 at 21:10


Thanks Woelen for the code, I hope I'll get better with this because... There's so much stuff on SM I want to discuss, ask question and hopefully contribute my 2 cents.
But considering the amount of experts here I feel like Wayne and Garth in front of Alice Cooper (seen Wayne's World?)

Quote: Originally posted by PHILOU Zrealone  

Oh un français toulousain :D ...
Bienvenue Monsieur! Wilkom, meine Herr! ;)
So you were in first raw to see AZF Toulouse blow...very interesting. I'm curious what are your speculations about what happened there and then. Did you see thunder in bals coming out of the ground prior to the blast? Did you eard two explosions at interval? There is a theory about a strange electrical blast in the underground of the SNPE a few km away prior to the AZF plant explosion and magnetic monopole could be involved...just like what happens when big earthquake happens in oil rich soil building very strong electrostatic potential and ground triboelectricity...this seems to have been cause of weapon depots explosions in Romania.


Not anymore "Toulousain" ;) And due to my ancestry I feel more European than anything else. I wont go into détails but I Americans always understand me and laugh ;)
Here is what I remember from the blast itself: I was sleeping !
I remember jumping 30 cm in my bed as if in a bad dream then went back to sleep. When I woke up, my first instinct before opening the shutters was to Wake the computer by moving the mouse around. I thought "damn, I must have been pretty high yesterday night and turned over the ashtray. It was none of this: it was the paint from the ceiling that once I managed to open the shutters halfway I realized it was as if it had snowed.
Phone lines were dead, Internet was still working so that's how I got my first news: from a friend living oposite town, on a hill whose Windows where blown off.

As for my speculations.... well. As I said, I have a mentor who's both a former Navy EOD, chemical engineer and now works for Total in a HSE position. The kind of paranoid guy you want as a friend when you're interested in EM. This was the first subject of conversation we had when we first met. He is adamant that Total had nothing to do with this and I believe it was not just "corporate loyalty".
In a few words, pretty much like what happened in Tianjin you can believe anything and everything at all. All the explanations make sense. It just feels like for "reasons of state" much of the truth was withheld and a scapegoat (Total was runnning this factory) needed to be found.
Why do I say this?
- You mentioned the SNPE. They were halfway dismantled and if what I remember is correct there were more into propellants than explosives. It is true though that the technical gallery with high voltage lines ran Under / close to the AZF site and to the SNPE factory (Now Eurenco).
- There were explosives on the site of AZF! 2x 500 pounds British bombs that were buried under the concrete close to where the electrical arc was produced! These may have accounted for something.
- Also present on site, a former disgruntled employee who's religion we wont mention. Lets just say he was fired the day before, was present unauthorized that day AND was wearing several layers of underwear as it had been known for kamikaze attacks.

There have been numerous theories about the Ammonium nitrate being slightly contaminated by fuel/organics from the vehicles moving around. Pure BS in my opinion. You'd need far more than the exhaust fumes from a vehicle to "sensitize" NH4NO3 in order to make a whole pile of several tons go high order.

My personnal theory? The electrical arc somehow set off the 2 WW2 bombs that were close enough to the Ammonium nitrate to make a sympathetic detonation. Or something else related to the SNPE in another way. That would corroborate the stories of people who were close enough (and not asleep) who clearly mentioned 2 explosions. That's why Total's been chosen as a scapegoat (reasons of state). And as for the wanna be djihadi... well, he was there on a bad day, perhaps non existant but is a good excuse to shuffle the cards a little more and be sure you never get a definitive answer from what happened there that day. Remember this was 10 days after 9/11 and nobody wanted a mass panic especially considering the French diplomatic position at that time. I dont like conspiracy theories, but there's something definitely fishy there!
The one thing everybody knows here is SM is that unsensitized, not properly mixed, and in pearl form NH4NO3 doesnt blow that easily without a good kick. Remember Oppau ! They routinely blew up Ammonium nitrate that had caked with dynamite until one day... well... you know the story.
I'd rather you ask me who killed President Kennedy :-/

Quote: Originally posted by PHILOU Zrealone  

Must have been horrible and frightening.

For someone sleeping... not really. The only information I got was through friends on IRC. The rest of the comms were down so I went out to look at the sky. As mentioned, it wasnt really the usual color... But I knew where the factory was and I was more concerned about the sound of EMT trucks. Lots and lots of people were staying close to Windows.

Quote: Originally posted by PHILOU Zrealone  

Yes we know, in such blast, not only the pure compounds do explode but also the all infrastructure (plastics, wood, stone, metals, oils) for a very special shade or colourfull panaché.

I've seen many explosions, not movie explosions thanks to my EOD friend who even though he is retired leaves his camera behind or stays with his old buddies when they blow up stuff.
This was not a clean white cloud of C4 or Semtex. That wasnt years old TNT with all the black soot.
This was brownish, yellowish with a hint of mustard. Very had to describe, the sky sometimes turns the same color before a storm. What was impossible to miss was the smell: and these, were clearly nitrogen oxydes. The structure was destroyed, but aside from the plant is was just a hangar so not much to be vaporized.

Quote: Originally posted by PHILOU Zrealone  

Acetylen is one of those rare gases that is detonable without air if pressurized and that display very large explosion limit...
This means it can burn, deflagrate or detonate in almost all % mixture with air...no need for perfect OB.
This explains the old tech carbide canon works so wel...
[Edited on 16-2-2016 by PHILOU Zrealone]


Hence the dissolution of C2H2 in Acetone. I'm a big fan of this kind of lighting and have been researching long at last how it was used before electricity replaced it all. I have to admit: our ancestors were geniuses! I even light up a carbide lamp when I have a female guest to make a more romantic ambiance. Works like a charm most of the time, way better than candles ;) The newest carbide lamps are made form a plastic that will rupture before overpressure blows up the acetylene. I can be quite scary, dirty and annoying when you are climbing a ladder and the generator of the guy right above you decides to give up !
Older models just let the gas through the pipe and into the water reservoir. It can be quite disconcerting when you have a lit lamp, an pond of water and fill the lamp without turning it off: water level rises, gas goes out and explosion ensues every time ;)

Here's a nice picture from one of these cannons I was talking about.

IMG_1149.JPG - 622kB
View user's profile View All Posts By User
 Pages:  1  2    4

  Go To Top