Gasoline Explosion/Detonation Pressure

[workinprogres]

At what pressure will regular gasoline spontaneously explode/ignite? Would it be safe to pressurize it to 100 PSI in a tank or would I blow up my house?

 

[Antiphon]

Do not. I repeat, do not store gasoline in your house. Pressurized or not.

 

[workinprogres]

By blow up my house I meant while pressurizing it, it's not going to be stored pressurized for more than 30 minutes max, and don't worry, I keep my gas outside in a shed anyway

 

[Borek]

I doubt it will explode. Gasoline alone is stable, it becomes flammable when it is mixed with air/oxygen.

 

[JaredJames]

In liquid form you should be fine. It's the vapour that would be your main problem.

 

[Borek]

Vapor alone - not mixed with oxidizer - is not a problem.

 

[DDTea]

Fuels can spontaneously ignite with enough pressure if oxygen is present: temperatures can get quite hot inside a vessel if pressure is high enough! That's how diesel engines and fire pistons work.

 

[JaredJames]

Vapor alone - not mixed with oxidizer - is not a problem.

Assuming you're storing it by conventional means, the chances are that when you filled it up not all of the oxygen was expelled from the container. So depending how much you fill the tank, determines how likely it is that you face a risk of ignition.

 

[Borek]

Fuels can spontaneously ignite with enough pressure if oxygen is present: temperatures can get quite hot inside a vessel if pressure is high enough! That's how diesel engines and fire pistons work.

While the ignition in diesel engine is spontaneous, it is not just a matter of high pressure. Air is compressed adiabatically and heats up, fuel is injected when the air is hot enough. Just because pressure is high doesn't mean gas is hot, a lot depends on how and how fast the pressure was built up.

I agree with most of remarks that the system is potentially dangerous, and that in the presence of air explosion is possible. All I am saying is just that the pressurized gasoline alone is not more explosive than a coal.

 

[JaredJames]

This is of course, all next to irrelevant until you determine the structural capability of the pressurisation container.

100 PSI isn't exactly a small amount of pressure and in itself is rather dangerous.

If the container bursts due to the pressure, you could end up with fuel all over your house and that is definitely a major issue and not something you want to be dealing with.

 

[chemisttree]

You'll put your eye out...

 

[workinprogres]

What I'm planning exactly is filling a fire extinguisher about 3/4 full of gasoline and pressurizing it with air from a bicycle pump. The extinguisher has been pressure tested recently to 500 psi and is fine. Since I will be using air as the propellant there is going to be oxygen present as well as gas fumes since the extinguisher isn't completely full which is what I'm worried about.

 

[JaredJames]

OK, now that idea is horrible.

Don't do it. You're asking for something to go wrong. In fact, that is combining a number of dangers in one.

 

[workinprogres]

OK, now that idea is horrible.

Don't do it. You're asking for something to go wrong. In fact, that is combining a number of dangers in one.

Alrighty then gasoline is off the list. Are there any other flammable liquids that would be aerosolized easily or should I just completely abandon this idea and add it to the very end of my bucket list

 

[JaredJames]

End of the bucket list sounds good.

Although that does still mean you're considering it, which is concerning. I'm sure there are better projects out there than a home made flamethrower (or whatever it is you intend using this setup for).

 

[workinprogres]

What I was building is a pulse furnace where a large amount of fuel is injected in an extremely short time into a small superheated space along with air to melt sand into glass and melt other normally non meltable things like rocks and crystals.

 

[Antiphon]

I think you'll be more satisfied with the following apparatus then.

Dig a pit and fill it with charcoal as in a standard barbeque. Get the coals going good and hot like you're going to roast a turkey. Put your sand and glass in the center. Then squirt a large volume of liquid oxygen into the pit.

Make sure you're at least 30 feet away from the pit or you'll die in the flash.

 

[workinprogres]

It won't be as cool but I guess that would work if I added an air supply

EDIT:
Didn't see that last part about liquid oxygen....

 

[JaredJames]

Make sure you're at least 30 feet away from the pit or you'll die in the flash.

I love that last bit!

 

[Antiphon]

It won't be as cool but I guess that would work if I added an air supply

Trust me- it will be far more impressive and you won't need an air blast. You'll need a heat shield and goggles.

 

[workinprogres]

If I could get liquid oxygen that is....

 

[Borek]

The idea is flawed from the very beginning. Just because you will deliver fuel and oxygen fast doesn't mean you will get substantially higher temperature. Heat will be carried away by combustion products way too fast. From what I remember each combination of fuel/oxidizer has its own maximum burning temperature.

Note that the thread can be locked at any moment: https://www.physicsforums.com/showthread.php?t=178906

 

[chemisttree]

What I was building is a pulse furnace where a large amount of fuel is injected in an extremely short time into a small superheated space along with air to melt sand into glass and melt other normally non meltable things like rocks and crystals.

A safer alternative to what you propose is to purchase a few fuel injectors (diesel) and a diesel fuel pump. Use kerosene or diesel fuel. Safety for that system is built in. You will need to arrange to have the electronics installed or leave the injector fully energized so the fuel is always flowing. You'll get a torch... a hot one. Two injectors put twice the heat into the system. Startup with an open flame. A spark may not do it. I would energize the injectors with 12V using a momentary switch or a standard SPST. All explosion-proof of course. If you don't know how to do that, give up until you do.

Careful. You'll put your eye out

 

[workinprogres]

Wow I never considered using fuel pumps, I think I'll give that a shot, Thanks! And I'll wear goggles so to keep both of my eyes