Where does the propane go?
Ol biscuit and I disagreed on whether or not is was possible for there to be air in a propane system basically with the tank valve shut and all the appliances turned off(valves shut). He said impossi...
Forum Discussion
JaxDad wrote:Both of you are mostly right but even though I've never tried carrying any propane in a pail, it isn't going to be exactly like carrying a bucket of water. The propane will be interacting with the atmosphere and the container. That segues nicely into my two questions above, which I have done.BB_TX wrote:
Propane is a liquid under high pressure and changes to a vapor when the pressure is reduced. It does not change back from a vapor state to a liquid state unless repressurized.
While that is true if you're talking about temperatures comfortable to most human beings, it's at the very least misleading.
Propane, at temperatures above -44 F. creates it's own 'pressure', because it's boiling. That is what causes the vapour to form.
At temperatures colder than about -50 F. you could walk around with a bucket full of it and would act pretty much like a pail of water would in warmer weather.
The answers: Since the vessel that holds the propane has internal pressure, when the propane is allowed to exit the 1" valve and enter the atmosphere, it is expelled quickly and also "flashes" into it's gaseous state. Since we reduce pressure by opening the valve (say, from 90 PSI to 14.7 PSI) the temperature is also lowered. The instant lowering of temperature causes some propane to remain liquid, some to vaporize, and some to even solidify with water vapor in the air.
Most can now guess the answer to #2--The ten cases of beer will have a glacier of combined propane and ice built around and on top of the stack. It was hard to keep thirsty deckhands away from the "beer cube" with their chipping hammers and sundry steel implements until the ice was allowed to melt and the propane was vaporized. It did work like a charm, ice cold beer in five minutes.
