propane/air vs propane/oxygen?

I would think that heat given from the propane/air is diluted with nitrogen and other gases, so the heat isn't as concentrated as with oxygen/propane.

Richard W.

Grant -

Propane and Oxygen burns hotter - much hotter than Propane and 68% ? Nitrogen we breath.

I used Natural gas and Oxygen in School - the school wouldn't let us have real gas - but natural gas was in the jets for burners - experiments . Heat was in hot water...

We got some Oxygen (allowed) and made up our own torch for the heavy soldering we had to do.

Oxygen is expensive - so if Air will generate the temp - let it rip. Use a pressure tank and regulator.

Martin

Air is 21% oxygen. Oxygen is 100% oxygen. More O2 means more fuel can be burned and more heat can be generated.

I'd have thought that anyone with some sense of dignity and pride or integrity and intelligence could figure that out.

Now I'm not so sure ..

-Carl

Much hotter. Most of the propane/air mix is dead baggage like nitrogen. Being an inverse proportion, this gets disproportionately bad for lower concentrations of oxygen, such as air. You can do a lot better with just an oxygen concentrator, you don't need it pure.

The question was about temperature, not heat. Heat is not temperature.

You can get any amount of heat you want from propane+air, and very efficiently.

Propane+air is lower temp than propane+O2 because the output is miserably diluted about 4:1 with cold nitrogen, water vapor, and the other gases in air.

So there is a lot of unburned propane in an air/propane torch? I don't think so.

So passing the nitrogen through somehow reduces the output heat .. hmmm.

Grant

Grant Erwin wrote: So there is a lot of unburned propane in an air/propane torch? I don't think so. ^^^^^^^^^^^^^ Let's do this "thought experiment." Think of a torch with three hoses and three valves: Oxygen, Propane and Nitrogen. Light the torch, and balance it with oxygen and propane. Measure the flame temperature. Now add some nitrogen. The nitrogen goes in at room temperature and comes out at the flame temperature, whatever that is. The energy to heat the nitrogen has to come from the combustion of the propane--thus it is no longer available to heat the carbon dioxide and water vapor formed by the combustion. Therefore the flame temperature goes down.

Btw...hows the new business coming ?

Gunner

"Aren't cats Libertarian? They just want to be left alone. I think our dog is a Democrat, as he is always looking for a handout" Unknown Usnet Poster

Heh, heh, I'm pretty sure my dog is a liberal - he has no balls. Keyton

Wet nitrogen, at that.

Because it wouldn't burn completely. You need to mix it with enough oxygen to fully burn the fuel. To do that with air, you have to use 5 times as much air as you would pure oxygen. The mostly nitrogen adulterant slows the rate of combustion, giving you a lower temperature flame. You'd get the same amount of heat, but diluted over a larger volume of lower temperature gas.

Gary

GE> OK, this is a question I've wondered about for a long time, which surfaced GE> when I was thinking about the rosebud torch question. I had a couple of years GE> of college chemistry back in the '80s, but that's about it. Here 'tis:

GE> Does a propane/oxygen torch burn any hotter than a propane/air torch? If so, GE> why? It's the propane that provides the energy, and there should be sufficient GE> oxygen in the air of a prop/air torch to fully burn the propane. If you use GE> the same amount of propane but mix it with a smaller volume of oxygen, why GE> would it put out more heat?

GE> Grant Erwin

Not more heat, but you do not have to heat the nitrogen in the air, so the temperature will be higher.

I don't see a smiley, so I suppose there is some personal animosity here. Why pollute the thread with it?

Bob

Propane molecule combining with oxygen molecules produce the same amount of heat whether they are diluted or not. Heat is an energy quantity, like money, or mass, or joules. It's measured in calories, like those for bread or yogurt. (Those are kilocalories. Let's not quibble.)

Termperature is the logarithm of the inverse of the thermodynamic probability and has made up units currently accepted as Kelvins or degrees Celsius or Centigrade. It is not an energy quantity and is not like money in the bank. It is a density sort of a quantity, like "how unlikely is THAT", with the concentration of oxygen being less likely than air. So a higher termperature for oxygen since the heat is concentrated in a smaller volume of space.

My senior project at ODU: Google Groups, then "dgoncz" and some of: ultracapacitor bicycle fluorescent flywheel inverter Equipped with BoBike Mini removable child seat, too!

Ozone is 150% oxygen.

Most definitely yes? When I do platinum work, I can only do it iwth my propane/oxygen setup, not with my prop/air (mouthblown) torch.

I don't know.

Abrasha

Yes there is. My prop/air torch has a lot more soot on it on a regular basis that I need to clean of than my prop/oxy torch.

Abrasha

it burns hotter just like oxy/act. burn hotter than just with act...... thats why they use act. with oxy... and if you dont think that oxy burns just put a match under an oxy tent in a hospital...

jim wrote: (clip). and if you dont think that oxy burns

^^^^^^^^^^^ Oxygen does NOT burn. Your "challenge" is silly. Anyone who tried to conduct that test would probably end up in jail, or in a psychiatric ward. "Burning" is the reaction of oxygen with fuel, liberating heat fast enough to be self-sustaining. So what would it mean for oxygen to "burn?" Reaction with itself?

Oxygen, in high concentrations makes the fuel burn faster, so it would be unwise to put a match into an oxygen tent. I suggest an experiment in which you fill one container (like a jar) with oxygen, and another with something like propane, or acetylene, or natural gas. Then apply a match. The difference will be immediately evident. The fuel-filled jar will flash. The oxygen-filled jar will make the match burn faster.