Explosion, Oil, Oxygen

[dho]

it is well said that oil mix with pure oxygen will have an explosion.
where the energy come from? it must be from the burning of the oil.
how can we calculate the intensity of the explosion?
for example, I have a device, may have .001 gram of oil inside an 0.1 cu in cavity. I charge it with 3,000 psi pure oxygen. how big a BOOM I will get?
thanks.

 

[ewh]

Pure oxygen is an explosive.

"Know the rules well, so you can break them effectively."
-Dalai Lama XIV

 

[dho]

"Pure oxygen is an explosive." very interesting statement, but i hardly agree with you.

 

[ewh]

You are correct... coffee hasn't hit yet.
I agree that it is the oil burning which provides the energy.

"Know the rules well, so you can break them effectively."
-Dalai Lama XIV

 

[WKTaylor]

d-h-o

The pressurized pure oxygen ensures rapid, almost complete, combustion of the oil... hence maximum gas expansion in a very short period of time.

In a tightly confined space, the initial flame front would probably travels fast-enough in all directions at-once, to equate to a definition of detonation. Depending on the ammount of fuel and oxidizer and the size/strength/toughness of the containment vessel this detonation could be: (a) contained [pressure hiccup]; (b) uncontained

May find useful data in any of the following, available at DTIC

http://www.dtic.mil/dtic/

AFAPL-TR-73-74 Fire and Explosion Manual for Aircraft Accident Investigators

AFWAL-TR-85-2057 Aircraft Mishap Fire Pattern Investigations

AFAPL-TR-79-2095 Dynamic, Hot-Surface Ignition of Aircraft Fuels and Hydraulic Fluids

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true.
o For those who believe, no proof is required; for those who cannot believe, no proof is possible.
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion"]
o Learn the rules like a pro, so you can break them like an artist. [Picasso]

 

[MikeHalloran]

The thing that's most dangerous about oxygen is that everything else is a fuel, including whatever contains the oxygen, even steel.



Mike Halloran
Pembroke Pines, FL, USA

 

[Compositepro]

One milligram of oil is hardly anything to be concerned with in almost any real world situation. It would be difficult to detect the effects of oxidizing this oil without a carefully controlled experiment.

 

[WKTaylor]

The military has strict rules regarding oxygen systems.

Anything that is considered a "fuel source" is prohibited from oxygen/inner-wall-passage contact, such as most** oils [petroleum or synthetic], teflon, organic materials, cleaning solvent vapors, etc. The explosion [over-pressure breeching] of a fully pressurized O2-system can quickly turn catastropic.... worst yet is a component breech releasing a jet of pure oxygen into a area where where it was never intended to go. I can attest to the raw power of an O2-jet suddenly feeding a small fire on plastic. It rapidly expands the fire zone and will burn any fuel [fabrics, acrylic, aluminum, magnesium, titanium etc] within that zone at enormous intensity [another mishap investigation story].

**There are special inert lubricants [like Krytox] for use in O2 systems; otherwise everything is 100% dry assembly.

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true.
o For those who believe, no proof is required; for those who cannot believe, no proof is possible.
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion"]
o Learn the rules like a pro, so you can break them like an artist. [Picasso]

 

[IRstuff]

The total energy of the reaction would be relatively low. Oil has an energy density of 48 MJ/kg, so a mg would result in 48J of energy released. That's about the energy of a 60W light bulb for 4/5 second.

TTFN
faq731-376

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[tbuelna]

I agree with what wktaylor notes about how the military or NASA approach contamination of oxygen systems. I have worked on launch vehicle LOx duct systems, and the procedures used to clean and protect the ducts prior to delivery were extremely rigorous.

 

[3DDave]

The biggest problem is thinking of pressurized O2 in the same way as the very diluted atmospheric O2. The problem is the ignition temperature of a material is lower as the oxidizer pressure goes up. A little drop of oil may not explode, but it can make a warm spot on the metal which may be higher in temp than the ignition temp of the metal for that oxygen pressure, causing the metal to ignite.

People have certainly seen a smoldering stick burst into flame when moved from atmospheric to an oxygen rich atmosphere.

At least it's not fluorine, which at STP is apparently energetic enough to ignite steel.

Looking interesting:

http://www.astm.org/BOOKSTORE/STP_SERIES/OxyFlame.htm

Each is a collection of articles, which are available separately.

STP 1561 - Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres: 13th Volume
STP 1522 - Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres: 12th Volume
STP 1479 - Flammability and Sensitivity of Materials in Oxygen-Enriched Environments, 11th Volume
STP 1454 - Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres: 10th Volume
STP 1395 - Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres: 9th Volume
STP 1319 - Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres: 8th Volume
STP 1267 - Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres:7th Volume
STP 1197 - Flammability and Sensitivity of Materials n Oxygen-Enriched Atmospheres, Sixth Volume
STP 1111 - Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres, 5th Volume
STP 1040 - Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres
STP 986 - Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres
STP 910 - Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres
STP 812 - Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres

 

[IRstuff]

1 milligram of oil should have about 48 joules of energy, given an energy density of 48 MJ/kg, which, if released in a 0.1 ci volume, would raise the air temperature by 24,000 degC, which would classify as pretty respectable explosion.

However, charging that volume with 3000 psi air would result in something more on the order a rise of 118 degC, which, while hot, is not much of an explosion. There is something to be said for getting the right stoichiometry and pressure

TTFN
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[berkshire]

Having been on the wrong end of an oil and oxygen fire, It is definitely a first cousin to an explosion.
I installed an oxygen system on an aircraft and during the first pressurization , we found out the hard way that a thread lubricant had been used on a regulator. the resulting fire and over pressurization only lasted about 3 seconds, it just seemed longer. resulting in us having to strip out the entire installation and start over.
B.E.

You are judged not by what you know, but by what you can do.

 

[3DDave]

B.E. Anything like this?

http://avherald.com/h?article=44078aa7

Egyptair B777-200

 

[berkshire]

3D Dave,
Nothing that spectacular, With us it was just Pffft and a small flame launched into the center of the cockpit, from the back of the regulator.
It did not touch anything else, but the regulator and the line leading into it were literally toast.
B.E.

You are judged not by what you know, but by what you can do.