You're forgetting that you are not compressing propane when you get it out of the cylinder... It is turning from liquid to gas and expanding - in fact cooling down.mega_swordman wrote: For Chaos, Spudthug is partially right. Compressing a gas (in our case, propane) in a closed container raises the temperature. However, an interesting point I also read is the fact that propane, when over 100C remains in a gaseous form. So, whether you achieve enough pressure to raise the temperature can only be tested.
If you started with a load of gaseous propane and then squashed it you would raise its temperature.
To get propane from a cylinder to over room temperature you would have to heat it.