Pure Oxygen
02-28-2004, 05:57 PM
#1
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Pure Oxygen
Ok, if I understand nitrous correctly, it is just lets more oxygen in the engine allowing you to burn more fuel=more power. I was sitting here thinking, why not use pure oxygen, instead of nitrous that has nitrogen in it?
02-28-2004, 06:32 PM
#2
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other then pure oxygen being so flammable you would need some serious fuel system to compensate. not to mention trying to tune it would result in deadly circumstanc.
Nitrous Oxide has a controlled amount of oxygen,therefore much easier to to tune and control ignition with.
Nitrous Oxide has a controlled amount of oxygen,therefore much easier to to tune and control ignition with.
03-01-2004, 01:03 AM
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While you are for the most part correct, I wouldlike to point out that oxygen, like nitrous oxide, is not flammable.
The reason that nitrous works so well is because as the nitrogen and oxygen split while being burned in an engine, it creates a cooling effect, keeping cylinder pressures and temperatures down. The nitrogen also acts as a buffer, lessening the "violent" effects of the extra oxygen being burned.
The reason that nitrous works so well is because as the nitrogen and oxygen split while being burned in an engine, it creates a cooling effect, keeping cylinder pressures and temperatures down. The nitrogen also acts as a buffer, lessening the "violent" effects of the extra oxygen being burned.
03-01-2004, 08:22 AM
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eehh pure oxygen is highly flammable,ever notice all the warning signs at hospital's?
yeas nitrous oxide isnt flammble,due to the molecular structure,when it breaks down to it's basics in the presence of heat,it supplies the oxygen to burn with more fuel (if supplied),or else it will run lean and detonate.
yeas nitrous oxide isnt flammble,due to the molecular structure,when it breaks down to it's basics in the presence of heat,it supplies the oxygen to burn with more fuel (if supplied),or else it will run lean and detonate.
03-01-2004, 11:09 AM
#6
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Originally posted by a walker
While you are for the most part correct, I wouldlike to point out that oxygen, like nitrous oxide, is not flammable.
The reason that nitrous works so well is because as the nitrogen and oxygen split while being burned in an engine, it creates a cooling effect, keeping cylinder pressures and temperatures down. The nitrogen also acts as a buffer, lessening the "violent" effects of the extra oxygen being burned.
While you are for the most part correct, I wouldlike to point out that oxygen, like nitrous oxide, is not flammable.
The reason that nitrous works so well is because as the nitrogen and oxygen split while being burned in an engine, it creates a cooling effect, keeping cylinder pressures and temperatures down. The nitrogen also acts as a buffer, lessening the "violent" effects of the extra oxygen being burned.
03-01-2004, 12:26 PM
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I really don't think you will see a lot of sensible heat absorbed (i.e. - cooling) by breaking the chemical bond between nitrogen and oxygen. I believe when the bond breaks it releases energy - see reference below confirming this.
The "cooling" effect is primarilly from the latent heat of vaporization, as the nitrous changes from a liquid to a vapor.
That cooling of the incoming charge gives you a colder, denser cylinder charge.... more oxygen from the "air" because you cooled the incoming air charge, and more oxygen from the higher mass% O2 in the N2O. As oxygen concentration in the cylinder charge goes up, the faster the combustion process, hence less timing advance required.
If you used pure oxygen, the oxygen concentration in the mixture could be elevated to the point where the speed of combustion is beyond control... and the O2 would start to combine with steel and aluminum as it melted from the intense heat. Ever see the glowing chunks come out of a top fuel dragster at the end of the track.. that is molten piston material..... from the very high O2 concentration provided by the nitromethane.
An understated reference:
The "cooling" effect is primarilly from the latent heat of vaporization, as the nitrous changes from a liquid to a vapor.
That cooling of the incoming charge gives you a colder, denser cylinder charge.... more oxygen from the "air" because you cooled the incoming air charge, and more oxygen from the higher mass% O2 in the N2O. As oxygen concentration in the cylinder charge goes up, the faster the combustion process, hence less timing advance required.
If you used pure oxygen, the oxygen concentration in the mixture could be elevated to the point where the speed of combustion is beyond control... and the O2 would start to combine with steel and aluminum as it melted from the intense heat. Ever see the glowing chunks come out of a top fuel dragster at the end of the track.. that is molten piston material..... from the very high O2 concentration provided by the nitromethane.
An understated reference:
A Boost for Fast Cars
At room temperature, N2O is quite unreactive with most substances, including alkali metals, halogens, and even ozone. It is therefore widely used as a propellant in aerosol cans in place of the CFCs which can damage the ozone layer. When heated sufficiently, however, N2O decomposes exothermically to N2 and O2.
If this reaction occurs in the combustion chamber of an automobile, 3 moles of gas would be produced from 2 moles, providing an extra boost to the piston, as well as liberating more heat. It also has a number of other benefits. The increased oxygen provides more efficient combustion of fuel, the nitrogen buffers the increased cylinder pressure controlling the combustion, and the latent heat of vaporisation of the N2O reduces the intake temperature. Therefore N2O is occasionally injected into the fuel lines of racing cars to give more power to the engine and to give the car exceptional acceleration.
At room temperature, N2O is quite unreactive with most substances, including alkali metals, halogens, and even ozone. It is therefore widely used as a propellant in aerosol cans in place of the CFCs which can damage the ozone layer. When heated sufficiently, however, N2O decomposes exothermically to N2 and O2.
If this reaction occurs in the combustion chamber of an automobile, 3 moles of gas would be produced from 2 moles, providing an extra boost to the piston, as well as liberating more heat. It also has a number of other benefits. The increased oxygen provides more efficient combustion of fuel, the nitrogen buffers the increased cylinder pressure controlling the combustion, and the latent heat of vaporisation of the N2O reduces the intake temperature. Therefore N2O is occasionally injected into the fuel lines of racing cars to give more power to the engine and to give the car exceptional acceleration.
03-01-2004, 04:48 PM
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Sorry guys, I may have been a little off in a with how nitrous works in an engine, but I'm sticking to my guns on one thing. Nitrous oxide and oxygen are not flammable.
Now, I'm no chemist, but I am the next best thing... I am a Hazardous Materials Tech A/B for the fire department I work for. If you look both materials up in the Emergency Response Guide book, they are listed as an Oxidizing gas, and use guide numer 122. Right there in plain English, it says, "Substance will not burn, but will support combustion", which means it is a non-flammable gas.
Now, I'm no chemist, but I am the next best thing... I am a Hazardous Materials Tech A/B for the fire department I work for. If you look both materials up in the Emergency Response Guide book, they are listed as an Oxidizing gas, and use guide numer 122. Right there in plain English, it says, "Substance will not burn, but will support combustion", which means it is a non-flammable gas.
03-01-2004, 05:42 PM
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I used to work with propane and oxygen torches at my old job. There was no way a striker could light compressed oxygen by itself. When lighting a torch you cracked the propane gas nozzle open and lit it with a striker and then added more oxygen and fuel until you got the flame hot enough. If you added too much oxygen it would blow out the flame. Like said above. Oxygen is an oxidizer and not flammable.
Matt
Matt
03-01-2004, 05:42 PM
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I used to work with propane and oxygen torches at my old job. There was no way a striker could light compressed oxygen by itself. When lighting a torch you cracked the propane gas nozzle open and lit it with a striker and then added more oxygen and fuel until you got the flame hot enough. Like said above. Oxygen is an oxidizer and not flammable.
Matt
Matt
03-01-2004, 10:42 PM
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Oxygen is oxygen, whether it is compressed or not. It has the same properties. I find it hard to believe a fire chief made that kind of a statement...must be why he's a carpentry teacher now. He must have never taken any fire science or Haz Mat classes.
Once again...oxygen and nitrous oxide are non-flammable gasses.
Like Nostang stated...have you ever used an oxy-acetylene torch? There are two cylinders. One is pure acetylene, and one is pure oxygen. To light the torch, you crack open the valve on the torch for the acetylene, then light it with a striker. You then add the oxygen in and add enough of an oxygen / acetylene mixture until you achieve the ideal flame. If you turn off the acetylene and leave the oxygen on, all you are left with is a small flame, about the same you would have with a cigarette lighter. If oxygen were a flammable gas, the flame would be much bigger and unstable, as it is when the acetylene is burning.
Once again...oxygen and nitrous oxide are non-flammable gasses.
Like Nostang stated...have you ever used an oxy-acetylene torch? There are two cylinders. One is pure acetylene, and one is pure oxygen. To light the torch, you crack open the valve on the torch for the acetylene, then light it with a striker. You then add the oxygen in and add enough of an oxygen / acetylene mixture until you achieve the ideal flame. If you turn off the acetylene and leave the oxygen on, all you are left with is a small flame, about the same you would have with a cigarette lighter. If oxygen were a flammable gas, the flame would be much bigger and unstable, as it is when the acetylene is burning.
03-01-2004, 11:00 PM
#14
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I think we're getting hung up on a technicality.... let's resolve it by quoting the MSDS sheet for oxygen:
Fire and Explosion Hazard Data
==============================================
Flash Point: NONE
Extinguishing Media: NONE SPECIFIED BY MANUFACTURER.
Special Fire Fighting Proc: OXYGEN IS NONFLAMMABLE, BUT SUPPORTS AND VIGOROUSLY ACCELERATES COMBUSTION OF FLAMMABLES. TO FIGHT FIRES, SHUT OFF
SOURCES OF OXYGEN AND FIGHT FIRE.
Unusual Fire And Expl Hazrds: OXYGEN SUPPORTS AND VIGOROUSLY ACCELERATES COMBUSTION OF FLAMMABLES. SOME MATERIALS WHICH ARE NONCOMBUSTIBLE IN AIR WILL BURN IN THE PRESENCE OF OXYGEN.
==============================================
Reactivity Data
==============================================
Stability: YES
Cond To Avoid (Stability): MATERIALS WHICH BURN IN AIR WILL BURN VIOLENTLY IN ATMOSPHERE RICHER THAN APPROX. 25% OXYGEN.
Materials To Avoid: ALL FLAMMABLES, ESPICALLY PETROLEUM PRODUCTS, ASPHALT, OTHER VOLATILE FLAMMABLES.
Hazardous Decomp Products: NONE SPECIFIED BY MANUFACTURER.
Hazardous Poly Occur: NO
Conditions To Avoid (Poly): NONE SPECIFIED BY MANUFACTURER.
==============================================
Flash Point: NONE
Extinguishing Media: NONE SPECIFIED BY MANUFACTURER.
Special Fire Fighting Proc: OXYGEN IS NONFLAMMABLE, BUT SUPPORTS AND VIGOROUSLY ACCELERATES COMBUSTION OF FLAMMABLES. TO FIGHT FIRES, SHUT OFF
SOURCES OF OXYGEN AND FIGHT FIRE.
Unusual Fire And Expl Hazrds: OXYGEN SUPPORTS AND VIGOROUSLY ACCELERATES COMBUSTION OF FLAMMABLES. SOME MATERIALS WHICH ARE NONCOMBUSTIBLE IN AIR WILL BURN IN THE PRESENCE OF OXYGEN.
==============================================
Reactivity Data
==============================================
Stability: YES
Cond To Avoid (Stability): MATERIALS WHICH BURN IN AIR WILL BURN VIOLENTLY IN ATMOSPHERE RICHER THAN APPROX. 25% OXYGEN.
Materials To Avoid: ALL FLAMMABLES, ESPICALLY PETROLEUM PRODUCTS, ASPHALT, OTHER VOLATILE FLAMMABLES.
Hazardous Decomp Products: NONE SPECIFIED BY MANUFACTURER.
Hazardous Poly Occur: NO
Conditions To Avoid (Poly): NONE SPECIFIED BY MANUFACTURER.
03-02-2004, 01:19 AM
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lmao... I am chem minor (Bio major), and I've worked with HazMat techs, so I'll explain this slower than normal <j/k> 
...
Combustion is the oxidation of a material, generally in a pace that liberates substacial heat. The definition is a bit hazy for some things like rust (which is iron oxidizing... in escence a slow burn of iron), but for hydro-carbons it's a simple issue:
CxH(x+2) + O2 -----> CO2 + H2O + heat
The fact that O2 is a reactant makes ANY excesive presence of it (or hydrocarbons) a concern for flamabilty. The term "flamable" TECHNICALLY implies that it can be easily oxidized and liberate catalysing heat... (by combining with O2) to produce a flame.
Here's the problem... pure oxygen would be 5 times the concentration of O2 normally seen in atmospheric conditions. O2 is the sole reason why hp exists, why things burn (oxidize), and what you're trying to concentrate in an engine when we do stuff like:
- supercharging/turbo charging
- nitrous injection
- Cold-Air Intakes (or icing an intake)
Granted, because oxygen isn't combustable itself (except in the case of ozone, but that's in the hazy area of "combustion without sustaining heat" and doesn't really apply here) it is fuel limited when talking about flamability... but any gas that's released into the atmosphere is only mixing with mostly inert Nitrogen, nobal gases, and of course Oxygen which it already had.
While the oxygen isn't flamable (you can't burn the oxygen with more oxygen), it is a HUGE fire risk as EVERYTHING ELSE will become flamable. At elevated O2 levels you'll see VERY weird things like the oxidation and even COMBUSTION of metals that would typically be stable (or slowing oxidizing like rust).
This is EXACTLY what is happening when you turn on the O2 in an acetylene torch. As you said, the acetylene is the limiting agent for combustion there... but it only burns at first becase of the O2 in the atmosphere. Adding the higher concentrated O2 from tanks is what really gets the combustion moving.
So yes... nitrous and O2 are not "flamable"... although they are HUGE fire hazards in the presence of any fuel (some of which you wouldn't even think COULD burn until you saw it actually react).
This statement however:
is WAY off base. I'd be damn suprised if the reduction of N2O was endothermic in any way. The cooling effect described is NOT due to a chemical change, but as Injuneer said, a physical phase change.
<smirk> oxygen being burned? I'll leave that alone this time, but your idea of a Nitrogen buffer is also wrong. 
When Nitrous gas is injected into the manifold, it doesn't get crammed in there any more than air of that temperture would. 100 nitrous molecules (N2O) will be displacing approximately:
78 N2 molecules
22 O2 molecules
Obviously the 22 O2 molecules normally present in air is actually a t step backwards. Displacing O2 with N2O gives you 22 LESS net Oxygens. The gain from diplacing N2 molecules however gives you 78 more Oxygens, for a net gain of 56 Oxygens... or a net gain of 27% more oxygen.
The break down of 100 N2O to 100 N2 will give you 22% more N2 molecules... but this is only for displaced gas.
The actual numbers of molecules displaced by a nitrous hit is mearly a fraction of what is there.
A 10-pound bottle of N2O has about 100 moles of gas... or approximately 2500 Liters of gas. At 5000 rpms, a 5.7L engine can go through that in about 5 seconds... assuming you ONLY ran off of nitrous. As you can see, even a nasty N2O hit only dopes the air a small amount... maybe 5% of the intake charge is N2O, and that means the N2 "buffer" is an increase in N2 levels by 1.1%... meaning that pressures are HIGHER after the breakdown to N2, and is definitely not a buffer. (higher pressures catalyse reactions... not dampen them)
The phase change is a good cooler to help out in concentrating atmospheric O2, but the O2 doping (of ~1.4% more) is the main benefit.
...Combustion is the oxidation of a material, generally in a pace that liberates substacial heat. The definition is a bit hazy for some things like rust (which is iron oxidizing... in escence a slow burn of iron), but for hydro-carbons it's a simple issue:
CxH(x+2) + O2 -----> CO2 + H2O + heat
The fact that O2 is a reactant makes ANY excesive presence of it (or hydrocarbons) a concern for flamabilty. The term "flamable" TECHNICALLY implies that it can be easily oxidized and liberate catalysing heat... (by combining with O2) to produce a flame.
Here's the problem... pure oxygen would be 5 times the concentration of O2 normally seen in atmospheric conditions. O2 is the sole reason why hp exists, why things burn (oxidize), and what you're trying to concentrate in an engine when we do stuff like:
- supercharging/turbo charging
- nitrous injection
- Cold-Air Intakes (or icing an intake)
Granted, because oxygen isn't combustable itself (except in the case of ozone, but that's in the hazy area of "combustion without sustaining heat" and doesn't really apply here) it is fuel limited when talking about flamability... but any gas that's released into the atmosphere is only mixing with mostly inert Nitrogen, nobal gases, and of course Oxygen which it already had.
While the oxygen isn't flamable (you can't burn the oxygen with more oxygen), it is a HUGE fire risk as EVERYTHING ELSE will become flamable. At elevated O2 levels you'll see VERY weird things like the oxidation and even COMBUSTION of metals that would typically be stable (or slowing oxidizing like rust).
This is EXACTLY what is happening when you turn on the O2 in an acetylene torch. As you said, the acetylene is the limiting agent for combustion there... but it only burns at first becase of the O2 in the atmosphere. Adding the higher concentrated O2 from tanks is what really gets the combustion moving.
So yes... nitrous and O2 are not "flamable"... although they are HUGE fire hazards in the presence of any fuel (some of which you wouldn't even think COULD burn until you saw it actually react).
This statement however:
The reason that nitrous works so well is because as the nitrogen and oxygen split while being burned in an engine, it creates a cooling effect, keeping cylinder pressures and temperatures down.
The nitrogen also acts as a buffer, lessening the "violent" effects of the extra oxygen being burned.
When Nitrous gas is injected into the manifold, it doesn't get crammed in there any more than air of that temperture would. 100 nitrous molecules (N2O) will be displacing approximately:
78 N2 molecules
22 O2 molecules
Obviously the 22 O2 molecules normally present in air is actually a t step backwards. Displacing O2 with N2O gives you 22 LESS net Oxygens. The gain from diplacing N2 molecules however gives you 78 more Oxygens, for a net gain of 56 Oxygens... or a net gain of 27% more oxygen.
The break down of 100 N2O to 100 N2 will give you 22% more N2 molecules... but this is only for displaced gas.
The actual numbers of molecules displaced by a nitrous hit is mearly a fraction of what is there.
A 10-pound bottle of N2O has about 100 moles of gas... or approximately 2500 Liters of gas. At 5000 rpms, a 5.7L engine can go through that in about 5 seconds... assuming you ONLY ran off of nitrous. As you can see, even a nasty N2O hit only dopes the air a small amount... maybe 5% of the intake charge is N2O, and that means the N2 "buffer" is an increase in N2 levels by 1.1%... meaning that pressures are HIGHER after the breakdown to N2, and is definitely not a buffer. (higher pressures catalyse reactions... not dampen them)
The phase change is a good cooler to help out in concentrating atmospheric O2, but the O2 doping (of ~1.4% more) is the main benefit.
Last edited by Steve in Seattle; 03-02-2004 at 01:44 AM.