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The Stig previously said:
In the peak of my paintballing days I had some CO2 tanks of mine overfilled on a hot day. We had left them in a parked car and when I came back I noticed a couple of them felt lighter than others. I didn't know why that was until I had later brought them up to my room and had a couple of them popped and start spewing CO2 into the room as I was sitting at my desk. It's actually in solid state when it's under pressure in a tank. ever played with dry ice? it's fun stuff.
It would be pretty nasty if you got enough solid CO2 into the tire to make it explode. You would prob have to try hard to screw up that badly though.
Nice mounting. Now you can take it of your "need:" list in your sig  |
Not to digress into total nerd-hood... (ok...maybe a little) but it's NOT in a solid state. It's a liquid.
The property of a pure molecular substance like CO2 can be modelled using something called a "phase diagram". The diagram is a graph on which the X axis is temperature and the Y axis is pressure. At any given temperature and pressure, the substance is either in a gasseous, liquid or solid state.
At room temperature and one atmosphere of pressure, CO2 is a gas.
However, if you lower the temperature while maintaining one atmosphere, CO2 will coalesce into a solid at about -78 C. At increasing pressures, it will maintain the solid state at higher temperatures.
At 5.11 atmopheres, CO2 can achieve a liquid state at -56.6 C. In fact, solid, liquid and gasseous CO2 can co-exist at that temperature and pressure.
If you maintain room temperature but increase the pressure to something on the order of about 1000 psi, CO2 will coalesce into a liquid. This will be liquid CO2 at 27 degrees C.
The gas space over the liquid within the pressure cylinder will be at equalibrium. If you release some of the gas, then liquid CO2 will boil off into gas form until the pressure is again equalized. For this reason, the pressure inside a tank of CO2 remains the same until all the liquid is gone.
However, when the gas goes from room temperature at 1000 psi out into the atmosphere at 14.7 psi, the expansion dissipates heat, resulting in lower temperature.
The gas/liquid inside the tank isn't cold... but when it escapes and depressurizes, it acts just like a refrigerator coil. This is true of any gas or liquid that is released from pressure.
"PV=nRT" is the ideal gas law which describes this phenomenon. If P (pressure) on one side of the equation is suddenly reduced, then T (temperature) on the other side follows suit.
