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Large explosion in Beirut

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Re: Large explosion in Beirut

#21

Post by vidanay »

throwaway0a5e wrote: post #18
macintux wrote: post #13

Earlier quoted context omitted.

I’ve also seen reports of grain silos in the area being destroyed; grain is an astonishingly powerful explosive.

Grain is a pretty poor explosive because the upper and lower explosive limits are so close (yes I know that's not traditionally a metric we use for solids), it needs an oxidier and the volume of byproduct for volume of input is relatively low. But large amounts of grain and oxygen are often found together in confined spaces so that makes it more explosive in practice than most things that people who work in offices a…

If there was a large enough explosions to blast the grain silos into the air and disperse the grain, it could find that "perfect" balance at some point and then flash over.

Re: Large explosion in Beirut

#22

Post by TimSchumann »

throwaway_pdp09 wrote: post #19
throwaway0a5e wrote: post #18

Earlier quoted context omitted.

Grain is a pretty poor explosive because the upper and lower explosive limits are so close (yes I know that's not traditionally a metric we use for solids), it needs an oxidier and the volume of byproduct for volume of input is relatively low. But large amounts of grain and oxygen are often found together in confined spaces so that makes it more explosive in practice than most things that people who work in offices a…

Can you elaborate what "upper and lower explosive limits" are, please. Also I don't understnd how it could be explosive at all, sudden oxidation of large (that is, low surface area to volume), non-dry particles seems unlikely. Flour etc. may be another matter, but a blast like this... flour?

Most grain elevators have incredibly large quantities of dust (basically flour) lying around, it's just unavoidable when you're moving that much grain around.

If it's too dry, there's a risk of static/friction/electrical ignition.

If it gets wet, you can have anaerobic bacteria build up heat in a compartment that, when exposed to oxygen, ignites.

Grew up on a farm, have a fair bit of experience messing around with grain bins. Our local elevator had a fire due to the former condition, and our neighbor's barn burned down due to the latter.

Re: Large explosion in Beirut

#26

Post by jcranmer »

macintux wrote: post #13
kcmastrpc wrote: post #5

Unconfirmed reports that a fireworks depot fire caused a secondary benzene explosion. src: https://twitter.com/mattparlmer/status/1290679715892690945

I’ve also seen reports of grain silos in the area being destroyed; grain is an astonishingly powerful explosive.

The first fire (pre-big-explosion) clearly is taking place in a warehouse next to the grain silos. The big explosion appears to take place in the same warehouse as well.

A single frame of the fireball shows a large spherical fireball whose edge maybe reaches the edge of the grain silos. The next frame looks to my untrained eyes more like the edge of the fireball is having some reflection from the wall of the grain silos, followed by a dark cloud obscuring details, and then the vapor cloud really obscuring everything, and finally the photographer falling over.

It seems pretty clear to me that grain played no role in the big explosion.

Re: Large explosion in Beirut

#28

Post by detritus »

wintorez wrote: post #16

What was that red material?

This is what I've been trying to work out, but am having problems Googling for suggestions. The only things I've in the past read as causing red smoke are highly carcinogenic/toxic hypergolic rocket fuels (hydrazine?), but I'm having a hard time imagining anyone storing a cache of that sort of thing anywhere near a built-up area.

The form of the explosion here points in my mind to something significantly more explosive than fireworks (fireworks result in white smoke too, no?) - if nitrates are involved, that might certainly point in a better direction.

Re: Large explosion in Beirut

#29

Post by wintorez »

detritus wrote: post #28
wintorez wrote: post #16

What was that red material?

This is what I've been trying to work out, but am having problems Googling for suggestions. The only things I've in the past read as causing red smoke are highly carcinogenic/toxic hypergolic rocket fuels (hydrazine?), but I'm having a hard time imagining anyone storing a cache of that sort of thing anywhere near a built-up area. The form of the explosion here points in my mind to something significantly more explosi…

The large explosion looked Thermobaric to me, which is not surprising since there were storing fuel there as well. I have a hunch that the red material could be some kind of grains, or construction material stored there as well.

Re: Large explosion in Beirut

#30

Post by interestica »

shock wrote: post #24

Anyone know why this has been flagged?

This seems ideal as an HN post to me - generating fruitful discussion and bringing in various viewpoints and areas of expertise. And the fact that it's a current event means that people have a bit of leeway in speculation: we all have the same limited source of information (on the ground video).
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