Oil and oxygen... when does it go BOOM?
 

I have a little project I'm working on with a buddy and we need to know at what pressures Oxygen and oil will cause an issue. I've heard it's only high pressure, but need to know for sure. Anybody have any details they can share about this reaction?

Thank you!

Makin a new one of them newfangled torches are ya?

I think if you mix it and throw a match on it, it will ignite at any pressure. However, I can't answer the question of when it changes from WHOOOSH to

BOOM!!!

...which I think is the purpose of your question.

It will ignite when you have a source of ignition at any pressure, but there's a specific point where the pressure is enough... need to know what that is. ;)

:lol: Shari... you're bad! ;)

Brent,

It is not the *pressure* of the Oxygen, it is the *concentration*. At standard atmospheric concentration (21%), oil is a combustible. At some higher level, oil becomes flammable. At an even higher concentration, it can spontaniously combust.

Obviously, an elevated temperature can also contribute to this.

Does this make sense?

Malcolm

I think this article explains what you're talking about, Malcolm. It's the oil, oxygen and the rate of oxidation of the oil.

http://www.woodworking.com/article_a...6&article=1718

I get that part... but at some point with pressure, as in a diesel engine, the pressure actually causes ignition without a spark or anything else. Extreme compression will cause combustion... and I need to know what pressure that happens at. ;)

But the compression (of air) in diesel causes heat and at a specific moment of great heat, the fuel is injected in HOT combustion camber to cause ignition....

With oil and pure oxygen its a case of rapid oxidation or "spontaneous" combustion...

Dale

My understanding Dale is that it's only under the high pressure that the oxygen and oil combination is instantly ignited. Under low pressure situations, it's flammable and possibly volatile, but it takes a spark. At some point, it doesn't take a spark... the pressure is enough.

Does this link help?

http://mulliken.chem.hope.edu/~polik...echniques1.htm

If you scroll halfway down the page you get this text:
Rotary oil pump must be on to reduce the pressure to <10-2 Torr (otherwise, hot oil could combust in presence of oxygen)

This one ought to help a bit.

http://www.ganoksin.com/orchid/archi...1/msg00060.htm

Ya know, I found this link and several others that state a pile of linseed oil soaked rags left to sit exposed to normal air can build up enough heat as it oxidizes to spontaneously combust. And that is just regular old atmospheric pressure.

I wonder if this is one of those questions that you get a different answer from everybody you ask. LOL

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

OK, so you're not talking about the flash point, you're talking about auto ignition. There's a difference, but don't ask me to explain it. All I know is there is a quite a temperature difference between the two. It's kind of like the difference between the whoosh and the boom.

So far, I've found you a chart that shows the auto ignition (boom) temperatures of various combustible fuels. Now we need to find out what pressure you need to apply to the oil to get it to the temperature listed on the chart. Here's the chart:

http://www.engineeringtoolbox.com/fu...res-d_171.html

Dude, I think you need a mathematician or an engineer....

I found this formula for determining temperature from the density and pressure.
http://www.engineeringtoolbox.com/co...ses-d_605.html

And this will tell you the density and volume of a bunch of combustible fuel products.
http://www.engineeringtoolbox.com/fu...mes-d_166.html

Here's one that tells you the temperature of air under various amounts of pressure.
http://www.engineeringtoolbox.com/ai...ity-d_771.html

There's a bunch of other stuff on this page, but this is giving me a headache reading all this math. GACK!
http://www.engineeringtoolbox.com/de...ity-d_290.html

It's got to be out there somewhere! You can find EVERYTHING on the internet if you know the proper terminology for what you're looking for. Unfortunately, I don't speak engineering geek.

I was hoping for an easy answer... but I guess I have to keep looking. Thanks for the links. I still have a few from a PM yesterday too. I would much rather be on the torch! :lol:

I really appreciate all the help you guys. :love:

I'm dealing with Oxy in the 100-200 PSI range if that helps anybody narrow down the specific dangers.

I've tried at up to 150 psi to try and get an explosion when doing destruction tests on pedals. I ended up getting frustrated when I could not make an thing happen. So I got curious, and put some oil in a 2 litter soda bottle with a tire stem in the cap. And filled it with o2. and left it outside for awhile and still nothing. I Shot the thing because I was afraid to go near it and disturb it. I blew up and was as loud as a m-80 going off.

So I thought I had success in getting it to combust. turns out the explosion was just from the air. NO flame or fire.

Because I filled up a perfectly clean bottle with just compressed air. Then shot that with the .22 and the first shot bounced off. Because the bottle was so hard and it hit off center. Second shot BA BOOM! Same as when I had it filled with o2. So the explosion was just the violent release of all that pressure.

I ended up talking to the guy at the welding place about the o2 and oil test. He said I would need high pressure not low pressure. He considered any thing under 300 psi low pressure. High pressure he was talking like tank type pressures. He said there is published date on what temps and pressures will cause ignitions. He thought the oil might make a difference to depending on what it is. He did say liquid o2 on oily rags will usually start a fire tho.

Tho he din't want to say ins not passable. He said its not probable or likely to ever happen at any pressure AFTER the regulator.

But I pretty much gave up trying being as it was not going to happen in any pressure range any one would ever be able to even accidentally run there o2 at in a glass shop.

My main interest was if it was passable that some one could run there o2 and propane threw there hoses for a long time and then at some point disconnect there hoses and reconnect them wrong and start running o2 threw a dirty oily propane hose. But it din't turn out to be any thing that would be catastrophic.

The composition of the oil should make a big difference in how it reacts with pure O2 at just about any pressure.

Robert

According to my son the car nut, since diesel engines can run biodiesel which can have the consistency of light vegetable oil, the compression ratio is going to be very similar.

Adding pure oxygen is going to reduce the ratio by about 30-40% (normal air has 21% oxygen). The problem is going to be that the "boom" is going to be very energetic because of the pure oxygen. You are going to need something like an automobile engine to contain it, otherwise you will shrapnel.

You will have to mist the oil and inject the oxygen somehow prior to the final compression, usually in an engine this takes place just before top dead center on the compression stroke of the engine. At top dead center is when ignition takes place, driving the cylinder down for the power stroke.

I'm trying to work out an oxygen delivery system for a torch... I don't want a boom any where along the way. Just trying to figure out how oil free the system really needs to be. There may be some residue in places along the way. Will definitely try to avoid it at all costs, but need to know before the tinkering really starts if 100-200 pounds is enough pressure for instant HOLY CRAP! :lol:

LMAO -- well, if you had said that to begin with!!!

You know, Brent, you might give Wally Horn a call. I am sure he can give you the info you seek.

Thanks guys... I've handed it over and I'm out of the loop now. Will just wait and see what the oxygen experts can come up with... let somebody else risk going BOOM! :lol:

Mike says you (or whoever) needs a copy of:

ANSI B31.1-1967 with addenda B31.10a-1969. "Gas and Air Piping Systems of Code for Pressure Piping". He says the information you need is probably in Section 2.

He also says that the allowable oil concentration is measured in ppm (parts per million). Basically, all components have to be washed in solvent prior to assembly, then assembled with gloves so that no finger oil can be on any oxygen contact surfaces.

He also found this on YouTube: http://www.youtube.com/watch?v=HAAbMvHbrJA

Oxygen/Oil towards the end, about 3 minutes in.

And flying scuba tanks: http://www.youtube.com/watch?v=tyINNUaXa8Q&NR=1

it depends on the metal a regulator is made out of. aluminum will cause fires at about 25 psi if there is ANY petrolatum based products including adhesive if exposed to the oxygen under pressure. temp. isnt as important as the concentration of the oxygen even liquid oxygen explode if exposed to oil and you drop a rock on it