- #1

OG63

- 2

- 0

Cylinder volume: 49.3 L

Initial cylinder pressure: 1250 psi

Final cylinder pressure: 625 psi

Initial cylinder temperature: 20 C

Final cylinder temperature: ?

Cylinder weight: 42 kg

Cylinder material: steel

I've included the cylinder weight and material for anybody who wants to look at the entire system. However, since this is a risk mitigation exercise, I'm willing to make any sort of simplifying assumptions that lead to a "worst-case scenario" answer for the gas alone (i.e., the maximum possible cooling).

For what its worth, I tried using an online thermodynamic calculator but got hung up when I couldn't decide what type of process this was. In one sense, it seems like an isochoric process (constant volume) because the cylinder volume doesn't change. But that didn't seem right because the volume of the initial gas charge certainly changed when half of it expanded into the open atmosphere. I also considered solving this as an isothermal process problem, with the idea that I might be able to calculate the amount of energy required to keep the temperature constant. But here again, I'm tripped up by the question of whether I should consider the system to be the initial amount of gas in the cylinder or just the half that's left in the bottle after dumping.

I should have paid more attention in Physics class, and so now must humbly request assistance from those who did.