4 ms·

Can someone explain the chemistry of natural gas exploding by itself? In my understanding, you need oxygen for that to happen. There's a bunch of oxygen in the

Can someone explain the chemistry of natural gas exploding by itself? In my understanding, you need oxygen for that to happen. There's a bunch of oxygen in the H2O, but what exactly would the products of an explosive reaction between natural gas and water be? Hydrogen and CO2? Don't think there's much energy to be released there... I can totally buy the "you depressurized only one end, so you had a plug slam into the next bend of the pipeline", and that might plausibly register as an explosion on seismic detectors. But hydrocarbons by themselves aren't explosive - they need something to react with.

wil421 4y ago
If you have pressures above 3,000psi any sudden leak or hole will be pretty catastrophic. Not an explosion like a fire explosion, something more like explosive decompression in a plane. Anyway I think they Swedes have pinned it down to an explosion, as in a bomb, based on seismometers.
- bombcar 4y ago
  Water pressure at 80 meters would be about 130 psi, so the pipe is 2800 psi over "ambient" which gives it a certain amount of "pop" should it do so. But it's also designed to not pop (and do we have any examples of a catastrophic pipe failure vs a leak?).
  - zasdffaa 4y ago
    I thought pressure of the gas as ~114 bar, which (brain whirring sounds) is much less than 2,800 PSI. MS's calculator makes it ~1,650 PSI I could be wrong.
    - bombcar 4y ago
      Could be the difference between what the pipe is rated for and what the gas is normally at.
    - wil421 4y ago
      If you google Nord Stream pressure the first link is to PDF that lists 220 bar as one of the pressures levels in the Nord Stream.[1] I can’t find the pressure level at the time of the explosion. [1] https://www.nord-stream.com/download/document/10/?language=en https://www.nord-stream.com/download/document/10/?language=e...
      - bombcar 4y ago
        >I can’t find the pressure level at the time of the explosion. Very high and then suddenly very low, I'd assume.
  - regularfry 4y ago
    It's designed to not pop, but implicit in the theory is that maintenance is shoddy and enough water has got in somehow to let hydrates form. Confidence in absence of pop may be misplaced.
- mannykannot 4y ago
  The thing is, the author repeatedly stresses how explosive methane is, without offering any plausible source of oxygen.
mannykannot 4y ago
Methane reacts with water (steam) when they are hot enough (over about 700 °C) but I am skeptical of it being explosive. https://9to5science.com/reaction-of-water-and-methane https://9to5science.com/reaction-of-water-and-methane An article linked to by the author mentions a case of rapid disassociation of the hydrate on heating, but the heat was applied to the pipeline externally, and probably at a point such that the disassociation occurred within the body of the plug, as opposed to one of its ends. https://petrowiki.spe.org/Hydrate_plug_removal https://petrowiki.spe.org/Hydrate_plug_removal
regularfry 4y ago
I'm wondering if it's a combination of the two, and a physical effect rather than a chemical one. If you run the hydrate plug into a wall, the hydrate at the impact site will get crushed and release its gas, which has a bigger volume than the original plug. Local pressure goes up so the force of the impact is magnified. That means a smaller impact has potentially an outsized effect. No idea if that works, because otherwise I think you're right. No oxygen, no kaboom. And if there was oxygen present, the leak would be on fire.
- MauranKilom 4y ago
  That would make the most sense. Methane hydrate + heat (from sudden compression of gas ahead) = a lot of methane sublimating.
zasdffaa 4y ago
"...and subject to Russian maintenance. And I’m here to tell you — Russian maintenance under the current oligarchy system isn’t any better than it was under the Soviet system." He is, as I read it, basically saying the methane may not be being properly isolated from the atmosphere so air may be leaking in. That said, you'd need a mega-massive-big input of oxygen contamination (wiki: "... 5–15% concentration [of air, not neat oxygen, IIUC] in a flammable or explosive mixture", and it would have to happen before gas pressurisation (or the methan would leak out, not air in). So I dunno.

wil421 4y ago

If you have pressures above 3,000psi any sudden leak or hole will be pretty catastrophic. Not an explosion like a fire explosion, something more like explosive decompression in a plane. Anyway I think they Swedes have pinned it down to an explosion, as in a bomb, based on seismometers.

bombcar 4y ago
Water pressure at 80 meters would be about 130 psi, so the pipe is 2800 psi over "ambient" which gives it a certain amount of "pop" should it do so. But it's also designed to not pop (and do we have any examples of a catastrophic pipe failure vs a leak?).
- zasdffaa 4y ago
  I thought pressure of the gas as ~114 bar, which (brain whirring sounds) is much less than 2,800 PSI. MS's calculator makes it ~1,650 PSI I could be wrong.
  - bombcar 4y ago
    Could be the difference between what the pipe is rated for and what the gas is normally at.
  - wil421 4y ago
    If you google Nord Stream pressure the first link is to PDF that lists 220 bar as one of the pressures levels in the Nord Stream.[1] I can’t find the pressure level at the time of the explosion. [1] https://www.nord-stream.com/download/document/10/?language=en https://www.nord-stream.com/download/document/10/?language=e...
    - bombcar 4y ago
      >I can’t find the pressure level at the time of the explosion. Very high and then suddenly very low, I'd assume.
- regularfry 4y ago
  It's designed to not pop, but implicit in the theory is that maintenance is shoddy and enough water has got in somehow to let hydrates form. Confidence in absence of pop may be misplaced.
mannykannot 4y ago
The thing is, the author repeatedly stresses how explosive methane is, without offering any plausible source of oxygen.

mannykannot 4y ago

Methane reacts with water (steam) when they are hot enough (over about 700 °C) but I am skeptical of it being explosive. https://9to5science.com/reaction-of-water-and-methane https://9to5science.com/reaction-of-water-and-methane An article linked to by the author mentions a case of rapid disassociation of the hydrate on heating, but the heat was applied to the pipeline externally, and probably at a point such that the disassociation occurred within the body of the plug, as opposed to one of its ends. https://petrowiki.spe.org/Hydrate_plug_removal https://petrowiki.spe.org/Hydrate_plug_removal

regularfry 4y ago

I'm wondering if it's a combination of the two, and a physical effect rather than a chemical one. If you run the hydrate plug into a wall, the hydrate at the impact site will get crushed and release its gas, which has a bigger volume than the original plug. Local pressure goes up so the force of the impact is magnified. That means a smaller impact has potentially an outsized effect. No idea if that works, because otherwise I think you're right. No oxygen, no kaboom. And if there was oxygen present, the leak would be on fire.

MauranKilom 4y ago
That would make the most sense. Methane hydrate + heat (from sudden compression of gas ahead) = a lot of methane sublimating.

zasdffaa 4y ago

"...and subject to Russian maintenance. And I’m here to tell you — Russian maintenance under the current oligarchy system isn’t any better than it was under the Soviet system." He is, as I read it, basically saying the methane may not be being properly isolated from the atmosphere so air may be leaking in. That said, you'd need a mega-massive-big input of oxygen contamination (wiki: "... 5–15% concentration [of air, not neat oxygen, IIUC] in a flammable or explosive mixture", and it would have to happen before gas pressurisation (or the methan would leak out, not air in). So I dunno.