What the hell makes GRAIN explode?

[annabanana]

http://www.newspressnow.com/localnews/29630012/detail.html

Three confirmed dead in Atchison explosion
Cause of blast still under investigation

Of the 12 individuals believed to have been at the grain elevator at the time of the explosion, Mr. Cocking confirmed emergency responders recovered the three bodies of Bartlett Grain employees around 3 a.m. Sunday and three other individuals remained missing. Four individuals escaped without injury but two others were transported to the burn unit at the University of Kansas Medical Center in Kansas City.

The cause of the explosion remained under investigation as the Kansas State Fire Marshall and OSHA officials surveyed the structure. The blast blew off a few stories of the grain distribution building that sits directly above the elevator, Mr. Cocking explained, and caused rubble to scatter around the structure.“It’s a fairly dangerous situation,” he said as smoke continued to rise out of the top of the grain elevator Sunday morning. “We don’t feel comfortable putting fire crews in right now.”

Mr. Cocking said workers were loading a grain train cart at the time of the explosion, but it remained unclear as to what triggered the accident. Rail service was suspended throughout the city of Atchison as the elevator continued to smolder Sunday afternoon.

Were there safety shortcuts? Is what we have here a case of spontaneous combustion?

[n2doc]

1. Dust. Very organic-rich dust

Same things has happened in Sugar mills and coal mines. You get a cloud full or organics, and all it takes is a spark (static electricity) to set it off. Really not too much different than a cloud full of gasoline vapors.

[hobbit709]

14. It's even been known to happen in lumber mills.

Anything with flammable dust can do it.

I remember setting off flour bombs as a teenager.

[GoCubsGo]

19. Sugar mills, too.

There was a huge explosion at a sugar processing mill outside of Savannah, GA a year or so ago. At least a dozen people died, and several were badly burned.

[dipsydoodle]

22. That the one.

Used to happen in our old cotton mills here in the UK.

[Javaman]

28. It's like the flour cloud experiment in chemistry class. nt

[Liberal_in_LA]

47. yep. I remember those.

[Boojatta]

40. Is there a way to make an engine that runs on sugar dust or coal dust?

[Ikonoklast]

42. Been tried long time ago.

Coal dust internal combustion motors only work for a short time before fouling from residual waste not being evacuated from the combustion chamber.

[dimbear]

44. Yes. In fact you can modify an ordinary car engine to run on coal dust.

It's been done. Probably not a real practical application. :)

[nebenaube]

2. Dust

If you have a high enough concentration of dust in the air, a spark of static electricity will ignite it. Much like a fuel-air bomb.

[Sivart]

3. Dust

Those elevators are probably very dusty. Dust explosions are completely real. There have been a couple at the local ADM plant in my area.

[NNN0LHI]

4. Just about any fine dust in an enclosed space can do this. Doesn't need to be grain

[ChairmanAgnostic]

5. grain elevators are often subject to explosions.

The grain dust is extremely fine, and hangs around the air. The slightest spark, even from someone turning on a lightbulb, is enough to blow it up.

IN fact, if you took 5 lbs of flour, and stood inside the monstrous Thompson Center in Chicago, then threw the flour out from the top floor, the slightest bit of electrical charge, and boom, no more building.

[uponit7771]

13. See, this is why I don't think we're under any REAL danger from terrorism. There are so many ways to

...disrupt our lives in this country that can be employed by the average person with some knowledge

[ChairmanAgnostic]

29. exactly. the whole shoe removal thingie is

little more than sheeple control at the aerodromes.

[SidDithers]

6. It's not the whole grain kernels, but fine dust that is explosive...

when it's suspended in the air.

Sid

[ChairmanAgnostic]

7. Heh heh. Think we made our point, yet? Achooo!

[SidDithers]

10. Heheh...

great minds, and all that :)

Sid

[Name removed]

17. Deleted message

Message removed by moderator. Click here to review the message board rules.

[SidDithers]

27. LOL...

:thumbsup:

Sid

[SidDithers]

39. Good call..

See post #33

Sid

[Ikonoklast]

45. I see a trend forming here...

:hide:

[Ptah]

8. It's not uncommon.

http://en.wikipedia.org/wiki/Dust_explosion#Sources_of_dust

Many materials which are commonly known to oxidise can generate a dust
explosion, such as coal, sawdust, and magnesium. However, many otherwise
mundane materials can also lead to a dangerous dust cloud such as grain,
flour, sugar, powdered milk and pollen. Many powdered metals (such as
aluminium and titanium) can form explosive suspensions in air.

[annabanana]

16. huh. . staff of life/ dust of death. .

learn something new every day

[awoke_in_2003]

46. When I read you post...

"Duck of Death" came to my mind (what Hackman's character called the British character in "Unforgiven")

[hootinholler]

48. Where's greywarrior when you need her?

Duck of death indeed.

I wish I would have saved that gif

[awoke_in_2003]

49. maybe GW finally released the duck...

and the duck sought revenge :)

[hootinholler]

52. IIRC she was holding the duck hostage until * left the white house. n/t

[slackmaster]

9. Flammable grain dust mixed in the correct proportion with air

http://www.youtube.com/watch?v=ka9mLeaaTLg

[AngryAmish]

11. Didn't you ever see MacGyver?

[guitar man]

12. Wheat dust

Wheat dust can be highly explosive when it's stirred up in the air in high enough concentration. I used to do millwright work on grain elevators and feed mills in my youth. One learns to look around at how much dust is stirred up before lighting a cutting torch or striking an arc with a welder. If you see a rosy colored glow around the torch...SHUT IT OFF!! :scared:

[Odin2005]

15. A few years ago the grain elevator in my little hometown exploded.

Grain dust is highly flammable and goes *POOF* easily.

[hobbit709]

18. I believe the correct term is "WHOOMP"

[ChairmanAgnostic]

30. the one word never seen on the old Batman series.

[Celefin]

20. Here's a good video of a dust-explosion simulator

http://www.youtube.com/watch?v=FYjqr1xjxy0

[FarCenter]

21. Put the end of a drinking straw in some flour; about an inch or two full of flour should do

Blow hard, expelling the flour as a cloud of dust over a lit candle.

Observe the result.

[ChairmanAgnostic]

31. but wear safety glasses when doing so.

Eyebrows grow slowly

[TwilightGardener]

23. They have dust systems in place, but they are moving tons and tons of grain

(in this case, corn) when they load a train, which can be as long as 110 cars and can take up to 15 hours to load. Lots of moving parts, lots of dust from corn that had been stored for months, lots of opportunity for a spark and ignition. I used to work at the bottom of one of those huge concrete silos--they had created tunnels and a control room underneath all the grain storage, they are dusty even with the dust systems. I always knew that if an explosion occurred at that particular elevator (one of many that I worked at), I'd be toast, no escape.

[mahatmakanejeeves]

24. Google "combustible dust osha"

Google "combustible dust osha"

Safety and Health Topics | Combustible Dust - OSHA

Combustible Dust - OSHA standards

Information at Vac-U-Max.com

[shraby]

25. Probably the same reaction that causes lightning in

volcanic eruptions.

[NYC_SKP]

26. I've taught science... Here is a fun experiment if you care to observe this interesting phenomenon

...

Materials: Corn starch or flour (fuel); a cardboard tube or PVC pipe 2 or 3 inches diameter and 24 to 36 inches long; little candle- birthday or votive.

Have a pinch of the fuel ready to drop into the tube, put lit candle on floor, place tube over it and quickly sift or drop the powdery fuel into the top of the tube and...

"Poof" you should get a mild explosion upon the ignition of the fuel.

In grain elevators, spontaneous combustion can occur, it doesn't take much of an ignition source to set off the poweder.

[Fire Walk With Me]

32. You haven't lived life until you've experienced militarized Wheaties.

[nadinbrzezinski]

33. Dust

And once you get a certain ratio to air, forgive me for forgetting the actual ratio, it goes boom. It is a fairly common accident. The other, due to dust, is people suffocating in all that grain. I was an urban EMT and still got one response to one of this. Fortunately local medics listened and did not go in until we came with breathing Aparatus.

[Prism]

34. A dream deferred n/t

[MahayanaLotus]

35. Monsanto?

[deaniac21]

36. You should see what my microwave does to popcorn.

[JVS]

37. The same thing that makes engines work.

Take something that can burn, and even grain can burn, suspend it in the air as dust, let the mixture compress, as dust does when pulled by gravity down the elevator, and you have a fuel mixture that could go off with a spark.
http://en.wikipedia.org/wiki/Grain_elevator#Elevator_explosions

[Uncle Joe]

38. Would that fine organic dust decay faster and low pressure create methane gas?

http://en.wikipedia.org/wiki/Methane

At room temperature and standard pressure, methane is a colorless, odorless gas.<4> The familiar smell of natural gas as used in homes is a safety measure achieved by the addition of an odorant, often methanethiol or ethanethiol. Methane has a boiling point of −161 °C (−257.8 °F) at a pressure of one atmosphere.<5> As a gas it is flammable only over a narrow range of concentrations (5–15%) in air. Liquid methane does not burn unless subjected to high pressure (normally 4–5 atmospheres).<6>

(snip)

Methane was discovered and isolated by Alessandro Volta between 1776 and 1778 when studying marsh gas from Lake Maggiore. It is the major component of natural gas, about 87% by volume. The major source of methane is extraction from geological deposits known as natural gas fields, with coal seam gas extraction becoming a major source (see Coal bed methane extraction, a method for extracting methane from a coal deposit, while enhanced coal bed methane recovery is a method of recovering methane from an non-minable coal seams). It is associated with other hydrocarbon fuels, and sometimes accompanied by helium and nitrogen. The gas at shallow levels (low pressure) forms by anaerobic decay of organic matter and reworked methane from deep under the Earth's surface. In general, sediments buried deeper and at higher temperatures than those that contain oil generate natural gas.

(snip)

Methane is not toxic; however, it is extremely flammable and may form explosive mixtures with air. Methane is violently reactive with oxidizers, halogens, and some halogen-containing compounds. Methane is also an asphyxiant and may displace oxygen in an enclosed space. Asphyxia may result if the oxygen concentration is reduced to below about 16% by displacement, as most people can tolerate a reduction from 21% to 16% without ill effects. The concentration of methane at which asphyxiation risk becomes significant is much higher than the 5–15% concentration in a flammable or explosive mixture. Methane off-gas can penetrate the interiors of buildings near landfills and expose occupants to significant levels of methane. Some buildings have specially engineered recovery systems below their basements to actively capture this gas and vent it away from the building.

[fishbulb703]

41. It's called a fuel-air explosion.

[Kaleva]

43. It's the dust.

[TransitJohn]

50. Oxygen, fuel, spark

Same as any fire. Didn't you ever have any chemistry? Combustion is simple redox reactions.

[krispos42]

51. When you powder something, you increase the surface area.

For example, a 1-pound block of wood has a certain surface area.

But if I shred it, that same 1-pound weight of wood now has dozens or hundreds of times the surface area.


Same thing with grain dust. By making it into a fine powder, each particle of dust can burn up instantly when exposed to flame. And the heat released by the combustion causes more combustion.


Of course, you need the right combination of circumstances. The powder has to be mixed with air, sort of suspended in the air. It has to be fairly concentrated, and you need a spark or other ignition source.