Sciencemadness Discussion Board - What did actually explode in Tianjin ?

3. The fireworks-like burning streamers seen coming down from thousands of feet in the air are burning sodium metal.

Where does that come from ? Unless Na metal was also stored at the warehouse.
Judging from a screenshot of the (poor quality) video the color of the streamers is white. When it were Na metal they would be bright yellow. No of the available chemicals was able to release Na metal in these explosions.

But, indeed NH4NO3 is a viable option. This can detonate rather easily.

Screen Shot 2015-08-16 at 17.13.02.png - 295kB

[Edited on 2015-8-16 by metalresearcher]

softbeard - 16-8-2015 at 07:31

Quote: Originally posted by metalresearcher

3. The fireworks-like burning streamers seen coming down from thousands of feet in the air are burning sodium metal.

Where does that come from ? Unless Na metal was also stored at the warehouse.
[Edited on 2015-8-16 by metalresearcher]

from j_sum1's post:
"...included sodium bisulfide, magnesium, sodium, potassium nitrate,
ammonium nitrate, and sodium cyanide, among others"

Burning sodium was the 1st thing I thought of even before I saw it as listed possibly being stored on-site. You can't tell the exact color from the footage. Looks yellow to me, BTW.

"This (NH₄NO₃) can detonate rather easily."
Actually, under normal circumstances, no it can't. Normally, unless sensitized, NH₄NO₃ can only be detonated by a very strong shock wave. However, as dozens of accidental explosions in the last 2 centuries have demonstrated, when large quantities of NH₄NO₃ (several tons or more) are involved in large fires, detonations do occur (last major one IIRC was a Texas fertilizer plant not too long ago).

[Edited on 16-8-2015 by softbeard]

hissingnoise - 16-8-2015 at 08:27

Quote:

I doubt exploding acetylene-air could cause this.

Well, air/ethyne mixtures are indeed powerful explosives as seen here!

softbeard - 16-8-2015 at 09:19

Acetylene/air may be a powerful explosive, but you would need at vey large volume of a 'just-right' mixture to cause the effects witnessed. Very unlikely scenario. Much more likely any acetlylene produced in the fire just burns quietly. Everything points to a solid-phase explosive rather than a fuel/air mixture as the culprit, in my opinion.

S.C. Wack - 16-8-2015 at 09:39

WTF

softbeard - 16-8-2015 at 09:49

The steel has melted from the intense heat of the fire.

phlogiston - 16-8-2015 at 09:52

Then why just that car, and not the surrounding ones?

softbeard - 16-8-2015 at 10:14

Uh, either,
1. Something focused a bit more heat onto the space it occupied.
2. It was a really shitty car.

Seriously, you can imagine dozens of scenarios. Maybe some burning 2-butanone (MEK), or whatever liquid was burning, pooled under it because the ground isn't perfectly flat. You can expect a lot of these apparent anomalies in a disaster zone like this.

froot - 16-8-2015 at 10:43

If there was Na in the mix then it's also possible the hydrogen generated from contact with water contributed to the massive detonation. Even if a relatively small amount of acetylene or hydrogen mixed with air and detonated that could've been enough to set the NH4NO3 off.
Those shockwaves are scary!

Edit:
Found this: http://www.news24.com/World/News/A-possible-list-of-the-haza...

[Edited on 16-8-2015 by froot]

Magpie - 16-8-2015 at 11:03

from j_sum1's post:
"...included sodium bisulfide, magnesium, sodium, potassium nitrate,
ammonium nitrate, and sodium cyanide, among others"

When I saw the white light I also thought burning metal. Perhaps they were storing powdered magnesium?

softbeard - 16-8-2015 at 11:15

Looks like iodine or iodine compounds were on-site

The fire was hot enough to melt steel

[Edited on 16-8-2015 by softbeard]

Gargamel - 16-8-2015 at 11:59

Looks like a car with aluminium body

The censorship is really a shame. Why don't these people protest much more against it?
Typically underdeveloped country...

softbeard - 16-8-2015 at 12:27

I agree. It's very possible the melted metal in the pictures is Al, not steel. I saw some what looked like melted engine blocks, but it could all be Al.

Bert - 16-8-2015 at 19:29

I have blown up/burned up several cars for movie or video shoots.

There are various parts made of such low melting materials as Al, Al alloys, Zinc and other low temp casting alloys- Similar molten puddles are quite commonly found under the burned out vehicle after using a liquid accelerant and low explosives for this type of effect.

When the STEEL melts or burns completely away... It was clearly a whole lot hotter than a fire aspirated by mild convection is likely to get.

Fire storm conditions with high speed winds being sucked into the burning area can indeed soften or completely melt steel structures, I wonder if the fire reached these conditions?

froot - 16-8-2015 at 22:10

Quote: Originally posted by S.C. Wack

WTF

Notice the painted parking lot line at the bottom right. I should paint my house with that!

metalresearcher - 16-8-2015 at 22:57

Modern car engine and wheel parts are sometimes made of Al alloy or even Mg alloy. When that latter starts burning is will result in a very hot fire.

What about thermite (common stuff for railway welding) stored in the warehouse ? This is usually sold ready for use in bags which should be emptied in a crucible over a railway seam and then ignited by an oxyacetylene flame or a sparkler.

So a high temperature source like burning Mg alloy or KNO3 / NH4NO3 with a combustible can set off a thermite bag and all the adjacent bags, resulting in a very hot fire (2500 C) which can easily ignite other stuff and result in such an explosion.

Gargamel - 17-8-2015 at 11:45

The crater reminds one of the Oppau blast in 1921:

oppau_explosion_germany_1921_detona_1321242841.640x0.jpg - 81kB

Crazy thing is, without the internet and modern technology the Chinese Gestapo would have held back the whole information.

And if it was up to them, we would never see a single picture.

[Edited on 17-8-2015 by Gargamel]

[Edited on 17-8-2015 by Gargamel]

[Edited on 17-8-2015 by Gargamel]

[Edited on 17-8-2015 by Gargamel]

careysub - 18-8-2015 at 06:47

Quote: Originally posted by Gargamel

The crater reminds one of the Oppau blast in 1921:

Indeed. This points pretty clearly to a condensed matter phase explosion.

[Edited on 18-8-2015 by careysub]

PHILOU Zrealone - 18-8-2015 at 09:33

Acetylen and cyanhydric acid both are endothermic compounds; as such they can detonate back to their elements generating heat...this can happen when shocked (pressurized), when heated or when explosive polymerization starts.

A stoechiometric mix of Acetylen/air in a 100L trash bag can blow a "maconery brick wall" down if put in contact aside and fired and that is just a few dozens of grams!

As a bonus those compounds burn with a lot of heat (flame temperature of acetylen is 3000-3100°C and that of cyanhydric acid is 3300-3500°C). The last compound is also quite toxic...and it seems it causes troubles now to people trying to clean the blast area.
Last but not least owing to their inerant explosivity on their own; those two compounds display a very large limit of explosion with air.

The amount of chemicals stored doesn't allow one to be sure of what exploded...
-NaCN is detonable with NaNO2 or NaNO3 for example.
-NH4NO3 is detonable or sensitized by a very long list of compounds .
-Magnesium and oxydisers may detonated
-Toluen diisocyanate may polymerise explosively under certain circumstances
-butanone may polymerise explosively under certain circumstances

By watching at the explosion video...one see the bright yellow-orange characteristic of divided carbon fuel (like the carbon dust/sooth formed during explosion of acetylen)...NH4NO3 would detonate much colourless/ with white fumes.

The falling flames are probably burning barrels of chemical products (flying bombs)...if such a barrel falls on a car, it will burn it very deeply and leave the rest of the cars almost unaffected.

If you are far from such a blast...the radiation of the heat could burn your car even if apparently at a safe distance of several hunderd meters!
In Belgium we had a gas pipe exploded (at Ghislenghien in an industrial area) with a flame of about 100 m...the radiation of this caused driving cars on the highway a few hunders meters away to burn or to melt)...the heat could be felt two kilometers away! Here the blast is much bigger and the gas involved probably more energetic so the radiation area should be even more than a few kilometers arround!

softbeard - 18-8-2015 at 14:55

"Acetylen and cyanhydric acid both are endothermic compounds; as such they can detonate back to their elements generating heat..."
Just what is 'cyanhydric acid' supposed to be? HCN? Cyanogen? Stop making up chemical names and expect other people to know what you're talking about.

Gaseous acetylene cannot "detonate back to their elements...". No. Only acetylene as a compressed liquified gas can be detonated. That's why nobody stores pure liquid acetylene in tanks. Then same goes for HCN; it will only polymerize explosively as a liquid.
"NaCN is detonable with NaNO2 or NaNO3 for example": reference please.

Tell me PHILOU Zrealone, how do you get a 20 ton TNT explosive equivalent out an of acetylene/air mixture? The acetylene/air scenario is ludicrous. If acetylene/air were such an effective explosive why would you ever need TNT or ammonal in bombs. The US Air Force should instead be dropping proximity-fused acetylene tanks from its planes.
Maybe you should check the density of your acetylene/air mixture compared to solid state (or liquid) explosives. Check how much volume only 10 tons of acetylene gas takes up at ambient conditions. I'll accept an ideal gas law approximation.

"NH4NO3 would detonate much colourless/ with white fumes" Huh? You've never seen NH₄NO₃ detonate, have you? I'll give you a hint, the products are N₂, O₂, H₂O, along with traces of NO & NO₂. See anything that gives white fumes?
Really, you're giving every indication that you're making this shit up as you go along.

Bert - 18-8-2015 at 17:13

"NH4NO3 would detonate much colourless/ with white fumes" Huh? You've never seen NH₄NO₃ detonate, have you? I'll give you a hint, the products are N₂, O₂, H₂O, along with traces of NO & NO₂. See anything that gives white fumes?
Really, you're giving every indication that you're making this shit up as you go along.

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.

Tell me abou your experience to the contrary?

If I must make an SFX HE shot for movie or video work purporting to be a TNT or similar low OB explosive and am limited to such AN based explosives, I wrap the charges in a bag of charcoal briquettes, the added carbon/powdered charcoal colors the vapor an acceptable dark grey/black color good enough for visual special effects work-

Please do not attempt to teach what you have not yet learned.

softbeard - 18-8-2015 at 18:08

Quote: Originally posted by Bert

Uh, Bert, are you entering the twilight zone too?
We're not talking about some idealized pyrotechnic mixture here. We're talking about a 20 ton TNT equivalent detonation. There is not enough time for making your TNT-simulation-pyrotechnic in this scenario.
Anyhow, Bert, this is night-time. You're not going to to see white clouds at night, even if they did exist.
What is the point of your argument? That exploding ammonium nitrate leaves white clouds behind? Really Bert? I'm sure if you add enough Al powder, Mg powder, C, and whatnot it will. But we're not doing a movie shoot here. And, no, an NH₄NO₃ detonation does not produce white clouds. Perhaps, Bert, you could point me to an example photo of this effect.
The point of this thread was what was the primary cause of the detonation witnessed at Tainjin. The primary cause is presumed to be a pure chemical, stored by itself. It may have been set off or sensitized by impurities but you assume the chemicals were stored in their pure form and that the bulk of the detonation was caused by that pure form.
"Water vapor condenses and leaves a white cloud": This is pyrotechnics talk and is a joke compared to the events in this case.

"Please do not attempt to teach what you have not yet learned.": Bert please understand what you are trying to argue before you attempt to argue it. The argument is not about white clouds being present or not.

"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."

Tell me abou your experience to the contrary?

Again Bert, you're talking about hypothetical Al sensitizers. This event was not a photo shoot with carefully-controlled pyrotechnic mixtures.

"If I must make an SFX HE shot for movie or video work purporting to be a TNT or similar low OB explosive and am limited to such AN based explosives, I wrap the charges in a bag of charcoal briquettes, the added carbon/powdered charcoal colors the vapor an acceptable dark grey/black color good enough for visual special effects work-"

Please do not attempt to teach what you have not yet learned.

Bert - 18-8-2015 at 19:27

So, essentially, you have never used ammonium nitrate explosives and have a theory that they produce no visible vapors?

j_sum1 - 18-8-2015 at 21:12

FWIW, although I appreciate your input softbeard, I have to acknowledge Bert's considerable experience in the field as a full time pyrotechnician. (Is that what you call yourself Bert?)

Bert, I would love your speculation as to what actually happened. I am reasonably satisfied that the second bigger blast (21 Tonne TNT equivalent) was caused by ammonium nitrate. Not being an EM expert I would love some more details. Under what conditions does pure AN detonate?
I am not at all sure about the smaller 3 tonne blast. What role if any do you think acetylene may have had to play? Opinion (both here and on other discussion boards) seems to be a bit divided on that one. What about the MEK stored? could that have gone bang? What else in the known chemical soup is a contender?

kecskesajt - 18-8-2015 at 21:54

Small amounts of ammonium nitrate is harmless.I use it to start campfires.But a huge amount is danerous becuase of the local overheating.
There could be a role in this reaction by the CaC2 because when it is mixed with oxidising agent,and lighed,it burns quite fast,
Maybe the AN/KNO3/NaNO3 melted and flown into the CaC2 and the CaC2 powder mixed with the oxidiser to form an intermolecular mixture.

Jimbo Jones - 18-8-2015 at 23:11

"Acetylen and cyanhydric acid both are endothermic compounds; as such they can detonate back to their elements generating heat..."
Just what is 'cyanhydric acid' supposed to be? HCN? Cyanogen? Stop making up chemical names and expect other people to know what you're talking about.

Gaseous acetylene cannot "detonate back to their elements...". No. Only acetylene as a compressed liquified gas can be detonated. That's why nobody stores pure liquid acetylene in tanks. Then same goes for HCN; it will only polymerize explosively as a liquid.
"NaCN is detonable with NaNO2 or NaNO3 for example": reference please.

Tell me PHILOU Zrealone, how do you get a 20 ton TNT explosive equivalent out an of acetylene/air mixture? The acetylene/air scenario is ludicrous. If acetylene/air were such an effective explosive why would you ever need TNT or ammonal in bombs. The US Air Force should instead be dropping proximity-fused acetylene tanks from its planes.
Maybe you should check the density of your acetylene/air mixture compared to solid state (or liquid) explosives. Check how much volume only 10 tons of acetylene gas takes up at ambient conditions. I'll accept an ideal gas law approximation.

"NH4NO3 would detonate much colourless/ with white fumes" Huh? You've never seen NH₄NO₃ detonate, have you? I'll give you a hint, the products are N₂, O₂, H₂O, along with traces of NO & NO₂. See anything that gives white fumes?
Really, you're giving every indication that you're making this shit up as you go along.

Absolute nonsense. In every aspect. But considering the fact that it comes from the same genius who made this statement --- "The steel has melted from the intense heat of the fire." --- I will not even bother to point the obvious.

Bert - 19-8-2015 at 00:15

Quote: Originally posted by j_sum1

a full time pyrotechnician. (Is that what you call yourself Bert?)

I am primarily a fireworks man. It is an honest name for someone engaged in that craft...

My master said that the historically correct English term for someone who makes and uses pyrotechnics was "PyrotechNIST", and "pyroTECHNICIAN" is a modern bastardization foisted on the world by ignorant, know nothing Americans-

It doesn't much matter to the general public, they will continue to call us all pyrotechnicians or just "pyros"! I don't call myself a pyrotechnician except when working as a TECHNICIAN- Typically, when I'm a hand on the set of a production where my activities are essentially limited to "plugging in" and using pre packaged, mass produced devices.

-------

My opinion on what blew up? That there are so many possibilities, a records search of the area's cargo container contents and locations combined with an engineering assessment of the physical locations of the dammage versus locations of various products and a forensic examination of residue and nature of blast effects on the surroundings would be required to say what caused the major blasts with any authority.

Hot ammonium nitrate in contact with a fuel certainly would be a suspect, given past accidents of this type.

PHILOU Zrealone - 19-8-2015 at 02:06

@Softbeard, alias Tom Liberman, BTW your family name from German/Dutch origin means "Gentleman",... don't forget it!

Sorry but I'm a chemical and biochemical engineer specialized in organic chemistry. I learn chemistry as autodidact since my 14 years old...at 15, I was already buying chembooks at university.
I read chemistry on a daily basis...so I know a lot. I also did experiments on my own the last 27 years.
So I may not know everything, but I think I know sufficiently to give several 50 cents comments of value. If I made a mistake, I'm the first one to admit it!
I think that you have first to read carefully what people wrote before flaming them.

1°)Cyanhydric acid, is just a very common name for cyanide of hydrogen, HCN ...just like chlorhydric acid is a common name for chloride of hydrogen or muriatic acid. A simple Google search on cyanhydric acid would have teached you that!

2°)At the end of my first sentence: "this can happen when shocked (pressurized)"...this means when pressurized or liquefied...so why pretending I'm wrong?

3°)References of detonation of eutectic mixes of NaNO2/NaCN or NaNO3/NaCN (or crossover with K salts) exists in many good extensive books about the chemical elements (some may be found in the Library of the forum).
Maybe you should read "Nouveau traité de chimie Minérale", by Manson & Cie Editor-1963-Tome II (fasicule 1 (Lithium (Li), Sodium (Na)); fasicule 2 (Potassium (K)). Each fasicule is about 800 pages, a kind of monography on the element and derivatives with physico-chemical properties...go and read NaCN,NaNO2, NaNO3, KCN, KNO2, KNO3 sections...

4°)Where did I state that acetylen-air was the only responsible?
Acetylen weights 26g/mole, one mole of gas at STP is arround 22.41 L
C2H2(g) + 5/2 O2(g) --> 2 CO2(g) + H2O(g)
So perfect OB mix is 22.41L acetylen and 22.41L*2.5=+/- 56 L oxygen (or 280 L air)
I just stated that acetylen/oxydiser is very potent explosive ... even if not compressed/condensed.
In the mix of gases formed by the heat and chemical mixes you may also have N2O, NO, NO2...all those form detonating mixes with acetylen and HCN all detonating above 3-3.5km/s in the gas state...pretty good for uncondensed explosives...TNT only reaches 6.5km as condensed.
This may have overheated other chemicals and lead them to explode/detonate.
To be so affirmative, do you have comparison datas of Lead Block Test for 10g acetylen/oxygen vs 10g TNT?
You might be surprised.

5°) Live with that NH4NO3 doesn't burn or detonate yellow-orange on its own. None of the explosion/burning products H2O, NO, N2, O2, N2O, NO2 produce a yellow-orange-gold color at the detonation-explosion temperature and yes some do condense in the fumes as white fog or with air moisture...
NO + O2 --> NO2
NO2 + H2O --> HNO2 + HNO3
H2O(g) --> H2O(l)
So NH4NO3 is not the only responsible chemical.
Beware that NH4NO3 is rarely used alone in blast and the extra-ingredient may cause yellow color (sodium (in emulsion slurries), cardboard, plastic container, ...)

[Edited on 19-8-2015 by PHILOU Zrealone]

hissingnoise - 19-8-2015 at 02:39

Quote:

Sorry but I'm a chemical and biochemical engineer specialized in organic chemistry. I learn chemistry as autodidact since my 14 years old...at 15, I was already buying chembooks at university.
I read chemistry on a daily basis...so I know a lot. I also did experiments on my own the last 27 years.
So I may not know everything, but I think I know sufficiently to give several 50 cents comments of value. If I made a mistake, I'm the first one to admit it!

Jeeez PHILOU, I don't think you should feel a need to in-any-way justify yourself to a hubristic knownothing like this guy?

Varmint - 19-8-2015 at 02:51

Hundreds, perhaps thousands of "Tannerite" shots on youtube, anyone can verify the color of the clouds in just a few seconds. There are even multi-ton NH4NO3 detonations done by the "ignorant, know nothing American" military disposing of fertilizer suspected of being useful in IEDs in Iraq and Afghanistan.

The interesting part is all the pontificating on the color of the clouds, what makes them get that way, how the chemistry of the detonation cannot provide either cloud nor color, in each one's mind doing this pontificating, "the science is settled".

The trouble is, the initial cloud dissipates rapidly so somebody is liable to come back in fighting about how "truly colored clouds wouldn't dissipate like that" or any number of other platitudes to attempt to prop up their previously stated position.

Here's my idea on what blew up in China: I have no fucking idea. It would be foolish and arrogant for me to even guess at it, because I have absolutely no way of knowing which reports to believe about what was or was not being stored. It might be fun to speculate, but look at the turn it took here.

Normally respected contributors beat down in grand fashion as if everyone has studied Blogfast's guidebook on how to be an internet prick, (co-authored by that jackass Bfesser), knowledgeable chemists providing absolutely impossible starting conditions that justify their statement on what blew up, and on and on.

Maybe someday cell phones and camcorders will come equipped with diffraction gratings and sensors that provide a spectral footprint. Then most anybody could tell the Chinese what blew up, or more likely, there could be arguments about the interpretations of said spectrographs as each jockeys for position as the master of supreme intelligence.

[Edited on 19-8-2015 by Varmint]

softbeard - 19-8-2015 at 04:07

Wow; it was not my intention to start a flame war here. If I've offended people, I apologize. I'm not looking for people's credentials here, and I think some of you (ie. PHILOU Zrealone , Bert) are being a little thin-skinned about this. Why is this degenerating into a discussion about whether white clouds formed or not?
PHILOU Zrealone, understand my point; even if C₂H₂ and HCN did form on-site from the chemicals present, they'd be in a gaseous form and non-detonatable. This is why I criticized your talking about them as endothermic and being a cause of the disaster.
Anyhow, I agree talking about what happened in Tainjin is all complete guesswork, but I thought that was the point of this thread. Instead, the thread is degenerating into posturing and insults.

BTW: When I Google 'Cyanhydric acid' the first thing that comes up is Cyanuric acid.

[Edited on 19-8-2015 by softbeard]

hissingnoise - 19-8-2015 at 04:15

Quote:

. . . multi-ton NH4NO3 detonations done by the "ignorant, know nothing American" military

Why do you hate the the federal armed forces so much, Varmint?

hissingnoise - 19-8-2015 at 04:37

Quote:

Instead, the thread is degenerating into posturing and insults.

Do you, perhaps, think your posting like an Über K3wl barely past the SWIM phase could have anything to do with it?

Varmint - 19-8-2015 at 05:28

Hissing:

If you read Bert's post, he was the one that felt obligated to take a swipe at America, so I was taking a veiled swipe at him with my comment.

Actually, my son is a SSgt. in the USMC, and I'm a diehard conservative, so I'm actually quite fond of the US military.

hissingnoise - 19-8-2015 at 05:48

Quote:

[quote=416487&tid=63322&author=Varmint]

Hissing:

Don't mind me, Varmint ─ I'm just taking the hiss . . . ?

Bert - 19-8-2015 at 07:08

Quote:

MEA CULPA! MEA MAXIMA CULPA!!!!!

"Foisted on the world by ignorant, know nothing Americans"

Please PM all related abuse to me PERSONALLY, leave the thread out of it!

Hi everyone!

This thread goes into lockdown and detritus after ONE MORE UNCIVIL POST.

I appologize for my own posting a reply to an off topic question that apparently ignited this flame war-

hissingnoise - 19-8-2015 at 07:42

It's gone baby!

Bert, how could you . . . ?

softbeard - 19-8-2015 at 08:18

I'll make one last note in this thread, then I'll keep my mouth shut. It's clear re-reading my original posts to PHILOU Zrealone & Bert that I've violated my own rules about ad-hominem attacks, and for that I've apologized...mea culpa.
I'll also admit I dismissed PHILOU Zrealone statement "NaCN is detonable with NaNO2 or NaNO3" without checking. It does make sense this could have happened.
From now on, when I see PHILOU Zrealone & 'Cyanhydric acid' I'll know he means HCN.

hissingnoise - 19-8-2015 at 08:26

(sigh!)'Tis in times such as these that I really miss Sauron and his inventive ASSTs . . .

Varmint - 19-8-2015 at 08:54

I too will apologize, I shouldn't have taken a shot at Bert for repeating what some jackass told him.

I just I was a bit sensitized by Ave's retort about "arrogant American" to another poster the other day, when she decided to pass off her comment as "a bad joke in answer to a bad joke". BS, she got caught, found a way out without actually having to apologize.

Frankly, I'm pretty well sick of America bashing. For decades it was understood by all (especially those doing the bashing) as nothing more than abject jealousy.

The Brits, who would normally be kindered spirits love to bash on "gun toting Americans", but the whole world knows they surrendered their freedom a century ago, and for them the only retort is to bash us, which is nothing more than trying to convince themselves that not being trusted by their own government is "advancement", and America is just simply behind the times.

Bloggie and others love to spout off about American homophobia and "invading brown people", well, this is more trying to convince themselves more than actually ranking on me and my nation. You see, once you've rolled over and submitted, the only option "to be a good subject" is to berate those who haven't been forced into accepting a formerly listed mental illness as "mainstream", and to rejoice that the name Mohammed and it's derivatives is close to the cusp of being in the top ten names in their formerly great nation.

Yep, slap America for being "behind the times, homophobic, and anti-immigrant" while you can, because once we succumb to the same BS we'll all be in the same boat, it won't make sense anymore. Then we can all reflect on what life was like before there were gays in every TV program or movie, and before Sharia was imposed by those "harmless immigrants just looking for a better life".

PHILOU Zrealone - 19-8-2015 at 09:00

OK

Opposites attracts!

Like likes like!

So everybody loves each other...let us make a big forgiveness hugh.

And back to chinese explosion debate. :cool:

hissingnoise - 19-8-2015 at 11:16

I think I'm going to be sick . . .

aga - 19-8-2015 at 12:44

It is obvious what happened.

It was a Food storage warehouse, mostly peanut oil.

This got too hot and boiled out all over 20 tonnes of dry prawn crackers.

I've seen those things go crazy in the frying pan before : almost as vigorous as poppadoms.

Edit:

America is a mess, just a Powerful mess is all.

UK, Europe, Asia, Africa, well, Everywhere is a mess.

I think the 'arrogant' bit comes from Americans believing it's not when it plainly is.

[Edited on 19-8-2015 by aga]

Loptr - 19-8-2015 at 17:31

It is obvious what happened.

It was a Food storage warehouse, mostly peanut oil.

This got too hot and boiled out all over 20 tonnes of dry prawn crackers.

I've seen those things go crazy in the frying pan before : almost as vigorous as poppadoms.

Edit:

America is a mess, just a Powerful mess is all.

UK, Europe, Asia, Africa, well, Everywhere is a mess.

I think the 'arrogant' bit comes from Americans believing it's not when it plainly is.

[Edited on 19-8-2015 by aga]

It must be the tall white aliens that run America...

http://www.forbes.com/sites/michaelpeck/2014/01/13/iran-says...

j_sum1 - 19-8-2015 at 18:08

As I read further, the inventory of the warehouse is undoubtedly a shambles with the paperwork bearing little resemblance to the actual chemicals on site.
I think we have all seen items shipped from China that are marked as "gift" or valued at $2.00 when neither of those statements reflects reality at all. Products labelled as something different: red P branded as iron oxide and so forth. It is entirely possible that no one had a clear idea of what was being shipped and in what quantities. What a mess!

Ozone - 19-8-2015 at 18:18

We neglect to mention that the warehouse may have been built over a long-forgotten weasel graveyard. Weasel bones are catalytic, IIRC. LOL.

Aside, whoa. OK. IF a shit-ton of CaC2 was stored in there, and they hosed down a small-ish fire, they could have ended up with a huge amount of C2H2 (fast, too). Now, C2H2 will definitely detonate via explosive polymerization if pressurized (which is why it's served in solution with acetone), but will burn softly in air. A proper C2H2:air mixture though (or, whoa, O2) will absolutely explode.

See what happens to a proper mixture of C2H2 and air in a balloon is ignited (doesn't take much, either, static will do it). Yep. Kaboom.

As kids, we used to "fish" with CaC2...3L soft drink bottle with a little water, a bag of CaC2 with a small hole, and a cap with a long bit of cannon fuse floated over the lake. Very impressive.

Imagine a few tons in a warehouse.

Still, pure speculation. Lord only knows what all they had (and in what quantities) illegally stashed in there.

It is kind of like those waste bottles from sophomore organic lab back in school...

O3

j_sum1 - 19-8-2015 at 18:26

Quote: Originally posted by Ozone

We neglect to mention that the warehouse may have been built over a long-forgotten weasel graveyard. Weasel bones are catalytic, IIRC. LOL.

No. Weasel bones are used for crucibles. They aren't catalytic.

Ozone - 19-8-2015 at 18:28

Well, I figured that if a rxn would only go in weasel bone crucibles, that some principle intrinsic to weasel bones was required. Sounds catalytic to me. YMMV.

LOL,

O3

j_sum1 - 19-8-2015 at 18:37

It was one of the great aga moments.

Ozone - 19-8-2015 at 18:44

True, that.

Bert - 19-8-2015 at 20:11

Having been to China repeatedly, and seeing how business is done- This is not a huge surprise:

http://globalnews.ca/news/2173216/company-used-connections-t...

China DOES have safety regulations, fire codes, zoning laws. They do understand risk management and there are many competent Chinese engineers to advise the rule making processes. But sufficiently well placed people may bend these rules...

DubaiAmateurRocketry - 19-8-2015 at 21:22

When i was chatting with the salesman of a small Chinese chemical company while i was trying to order some products, they said shipping some perchlorates depends on the time being shipped, occasionaly they are able to ship it, but the salesman tells me that whenever a small accident happen related to hazardous chemicals, regulations on shipping becomes extremely strict and starts to loosen over time, he says could be month or years. I did get my perchlorate years back then when i ordered, and a month later a small firework truck was burnt killing a handful, that chemical company went bankrupt very soon due to the high strictness of shipping, and hazardous materials was what that company was for.

Bert - 20-8-2015 at 00:29

Just for giggles, tonight I mixed a small sample of a stoichiometric amount of fine powdered calcium carbide ("Bangsite" carbide canon ammo) with some fine powdered ammonium nitrate and played a propane torch over it. WHOA!

I would be interested to see what it behaves like with a blasting cap-

PHILOU Zrealone - 20-8-2015 at 01:50

Quote: Originally posted by Bert

Just for giggles, tonight I mixed a small sample of a stoichiometric amount of fine powdered calcium carbide ("Bangsite" carbide canon ammo) with some fine powdered ammonium nitrate and played a propane torch over it. WHOA!

I would be interested to see what it behaves like with a blasting cap-

I was also wondering the result of such a mix...
With water entrapped in the NH4NO3 (hygroscopic):
NH4NO3 + H2O + CaC2 --> H-C#C-H + CaO + NH4NO3 + heat
H-C#C-H + CaO + NH4NO3 + heat --> H-C#C-H + Ca(NO3)2 + NH3 + H2O + N2O + heat
Ca(NO3)2 -heat-> CaO + 2 NO2 + 1/2 O2

Without water is works also but heat is needed first to decompose NH4NO3 to yield a little water:
NH4NO3 -heat-> 2 H2O + N2O

Anyway in the reaction products:
H-C#C-H (endothermic from its elements)
NH3 (endothermic from its elements)
N2O (endothermic from its elements)
NO2
O2
So the resulting gas mix is a very potent explosive

aga - 20-8-2015 at 15:09

Perhps it was A load of fluffy toys, Arduninos, submersible solar powered fountains and a huge pile of TNT ?

Reverse engineer from the available data (just a video).

Start with the facts.

What are the trail-leaving brightly burning bits ?
No random guesses : what Can do that and under what conditions ?
Make a list.

Next the Character of the central explosion : what Can behave like that ?
Make a list.

This is just detective stuff, it isn't even Science.

We need a Poirot.

[Edited on 20-8-2015 by aga]

Bert - 20-8-2015 at 15:42

The long trails of liquidy looking fire is something that used to be done with white phosphorous from a rocket heading- "Liquid fire rockets", it can also be done with some Sodium metal chunks loaded into a rocket heading.

I would guess we are seeing ruptured containers of Sodium metal falling from the sky.

Ozone - 20-8-2015 at 16:24

It looks like they found some of the missing cyanide. Of course, the despite the abundance of evidence to the contrary, the Chinese Govt. asserts that the water isn't toxic.

I suppose it could be a "normal" fish-kill event, but the timing and location are uncanny:

http://www.dailymail.co.uk/news/peoplesdaily/article-3204797...

Also, "The warehouse housed around 40 different hazardous chemicals, including 700 tons of toxic sodium cyanide, 800 tons of ammonium nitrate and 500 tons of potassium" might explain some of the "burning metal" which was observed--Also a nice source of hydrogen and fire if wet with say, a fire hose.

O3

j_sum1 - 20-8-2015 at 16:46

Quote:

500 tons of potassium

Sheesh!

Bert - 20-8-2015 at 16:55

Ah. Potassium, it's all good...

http://youtu.be/HY7mTCMvpEM

(Edit)
If there was really 800 tons of ammonium nitrate on hand, the city was VERY lucky if the blast truly was only 22 tons of TNT equivalent. That crater looks a bit large for the TNT equivalent estimate given, but this type of forensics is not my area of expertise-

[Edited on 21-8-2015 by Bert]

Ozone - 20-8-2015 at 17:02

Yeppers. Ka-boom.

And, nice video. Bad-ass. We sure knew how to do it, back in the day.

O3

PHILOU Zrealone - 21-8-2015 at 02:24

This is just detective stuff, it isn't even Science.
We need a Poirot.
[Edited on 20-8-2015 by aga]

Hercule Poirot is a compatriote, the famous belgian detective.

Maybe we need also some londonian input from Sherlock Holmes

PHILOU Zrealone - 22-8-2015 at 09:50

As a disaster never comes alone...kind of serie rule (*):

Another chemical plant in the east of China, did explode this saturday 22th of augustus 2015.
Huantai district, area of Shandong.
The explosion generated a fire arround 20:50 local hour in the chemical plant of Shandong's Runxing Chemical company.
More than 10 firemen vehicles try to surround and temper the fire.

Windows of the builings and houses of the village where the plant is placed have been blown away and tremors of the explosion were felt more than 2 km arround.

(*)Like one of my french teacher used to say:
Troubles are like toilet paper, you pull to take one or two leaflets...and it is the all paper rol that comes down...

[Edited on 22-8-2015 by PHILOU Zrealone]

James Ikanov - 4-9-2015 at 13:15

Quote: Originally posted by metalresearcher

A big explosion in Tianjin in a chemicals storage area happened with sad results.

I think this will greatly impact on safety regulations in Chinese production and storage facilities.

But as a chemistry hobbyist (but not the least important, the safety authorities) I want to know WHAT actually exploded ?

A buddy of mine got ahold of a list of stored materials that was in one of the warehouses. One of our pasttimes whenever something like this is to dig up whatever we can on it and speculate about what happened.

Based on the footage and the list, here's what I think happened:

Fire spread into the warehouse. The warehouse contained everything from pressurized propane to liquid Toluene, Acetone, and MEK. A container of some kind of flammable liquid was ignited and burst. The fire spread to the pressurized containers, which acted as an FAE device across the surface of the fire, generating enough heat and pressure to cause the Nitrates to release oxygen.

I think the footage is consistent with an FAE type explosion, not something like a chemical explosive so much as a massive, MASSIVE fireball. IMO it could've been a lot worse if the tanks had managed to leak for a bit before exploding.

IIRC there were also organic peroxides of some unknown type in the warehouse.

aga - 4-9-2015 at 14:13

A buddy of mine got ahold of a list of stored materials that was in one of the warehouses .... which acted as an FAE device across the surface of the fire

So what was in there, and what is an FAE device ?

battoussai114 - 4-9-2015 at 19:52

A buddy of mine got ahold of a list of stored materials that was in one of the warehouses .... which acted as an FAE device across the surface of the fire

So what was in there, and what is an FAE device ?

Field Active Effect... no, Funny Acetylene Ether. Fire Assesment Element. Ferocious Acrocanthosaurus Enragement... yeah, no idea.

Varmint - 4-9-2015 at 20:37

Fuel-Air-Explosive

Yes, I'm aware anyone questioning it knew that already...

James Ikanov - 9-9-2015 at 14:24

A buddy of mine got ahold of a list of stored materials that was in one of the warehouses .... which acted as an FAE device across the surface of the fire

So what was in there, and what is an FAE device ?

Fuel Air Explosive, as said previously. (sorry about leaving you hanging, I don't check things that often

)

Went and found what he sent me:

Chemicals: Compressed and liquefied gases (argon, compressed natural gas); flammable liquid (methyl ethyl ketone, ethyl acetate); flammable materials(sulfur, nitrocellulose, calcium carbide, calcium alloy); oxidizers and organic peroxides (potassium nitrate, sodium nitrate, etc.); toxic chemicals (sodium cyanide, toluene diisocyanate)

My friend is always vague about where he exactly gets this information, but it's usually correct and if it's not he'll update me after the fact.

In this case he said he browsed a number of Chinese news reports and found at least one interview with factory workers and first responders about what was in the warehouse. The list above is pretty much an exact quote from what he sent me on Skype. I don't think it's complete but it should give you an idea of how stupid bad the safety here was.

It's not exactly a hobby but we both go pretty deep into some pretty obscure rabbit holes to find stuff like this and analyze it.

careysub - 9-9-2015 at 14:49

I think trying to invoke a "fuel air explosive" effect is really reaching, and without any real support.

There are three separate explosions within about 4 seconds - a "small" initial one, the main explosion about 3 seconds later, and a secondary explosion intermediate between the first and second, within about a second of the main explosion.

I think they were just different batches of ammonium nitrate (and possibly other materials) exploding.

James Ikanov - 9-9-2015 at 17:58

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.

I'm not an expert, this was just the opinion I reached based on watching some footage with large, obvious and upward columns of flame. I've seen similar footage from a site in the middle east that was supposedly used to store and fuel liquid or solid rockets in some kind of underground ammo dump, right down to the columns of flame and small chunks of visibly burning metal.

for example, ball of flaming gasoline and then an actual FAE:

https://www.youtube.com/watch?v=7dW1qkBg8sM

Obviously not the same as:

https://www.youtube.com/watch?v=QBH-S2F6ajY

But I think a significant component of at least one of the explosions was a flammable vapor suspended in air. It's not a true FAE so much as a really really big incendiary device. If there was AN present (which I have not heard an account of yet, only KNO3 and NaNO3) then it is plausible to me that that would be a huge contributor. But still, I think most of it was flammable liquid or gas. Just my two cents.

The thing that I'm really curious about was the reference to organic peroxides of some kind being stored in the warehouse. I know MEKP has some usage in epoxy hardening or some such, but they don't ever actually explicitly state what kind or how much of the stuff, nor what concentration.
Is it plausible that MEKP at 35% being heated very aggressively by a fire could explode?

careysub - 10-9-2015 at 10:22

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.)

James Ikanov - 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]

aga - 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 ?

careysub - 10-9-2015 at 12:55

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.

Bert - 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.

Mush - 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

aga - 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.

j_sum1 - 14-2-2016 at 16:38

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

Detonationology - 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...

j_sum1 - 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.

morganbw - 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.

Bert - 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...

Herr Haber - 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]

PHILOU Zrealone - 16-2-2016 at 03:11

Oh un français toulousain

...
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.

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.

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.

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]

hissingnoise - 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 . . . ?

PHILOU Zrealone - 16-2-2016 at 13:41

Quote: Originally posted by hissingnoise

Quote:

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)

Herr Haber - 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?)

Oh un français toulousain

...
Bienvenue Monsieur! Wilkom, meine Herr!

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 :-/

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.

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.