How long does propane last?

[crusader rabbit]

Bill, my pappy has had propane torch tanks stored in the garage at his place in Mesa, not that far from you--some for over 20 years--and they are still just fine.  I suspect the seal will start leaking the first time they are used, but they are still holding pressure.  Personally, I would probably like to see them stored outside the garage, but still under some shade from direct sunlight.

And Quaker, propane--C₃ H₈ or butane C₄ H₁₀ (similar gasses) are hydrocarbon gasses and will last indefinitely until they are chemically changed by combustion.  You can also alter their form by compression.  Compress them enough and they become liquid (that's what you hear/feel sloshing around in the cylinder.  Their composition can be altered by introducing other elements--something you are unlikely to try outside of a lab.

The concern, as has been mentioned above, is the integrity of the tank.  If you see obvious deep rust (Iron oxide has something like 80-times the volume of solid iron, so even something that looks bad may be from a very thin layer of original material), take the tank away from any structures and/or ignition sources open the valve.  If these tanks are as old as I suspect, they will not have the intigrated safety feature that prevents the discharge, and they will empty out into the atmosphere.  If they are newer, you will have to hook up a hose fitting or the gas won't release.

If these tanks were mine, I would hook 'em up to my bbq, buy quantities of pork ribs, beef ribs, and hamburger meat, invite over my plethora of friends who like free food, and stipulate that they must bring beer.  I would move the bbq away from the house for this activity, but there really should be no great worry.  Of course, if you hear a hiss, make a hasty retreat.  You are unkilely to get an explosion--buut you could see a pretty neat flare for awhile.

You could also try shooting them with a tracer (keep a very safe distance) and enjoy the ensuing explosion.  If you get sent to prison anywhere in my neck-o-the-woods for terroristic activity, I'll come see you and bring some homemade cookies.

[Timothy]

I'll add to CR's post that, if you do vent these tanks to atmosphere, make sure the neighbors aren't watching.  It's illegal in my area, don't know about Florida. 

Smoking during this procedure would be ill advised as well...

[tombogan03884]

From CR's post :
"I would hook 'em up to my bbq, buy quantities of pork ribs, beef ribs, and hamburger meat, invite over my plethora of friends who like free food, and stipulate that they must bring beer. "


This FQ we're talking about, the guy who has to tie a Hibiscus flower around his neck to get the Iguana's to play with him.

[fightingquaker13]

That's just to lure them in close for the kill Tom. And an excellent source for using up gas for the free BBQ. "Oh, that, its chicken? Done up Guetmalan style, its got an interesting marinade don't you think"?
FQ13

[Solus]

If you vent them, do it on a breezy day.  

Propane is heavier than air and will accumulate in low areas (this is the reason LP is NOT a good idea to be use on boats)

CR has the best idea.  

If you don't use your tanks enough to have they refilled before the tank expiration date, have that BBQ.  

If you do use them quick enough, have them refilled until the last refill before expiration, then do the empty exchange.

They don't check the expiration date on the tank you bring in and they will give you an unexpired full one.

Haven't done any costing on these two options so I don't know how they compare.  The exchange path does take less time as there is no waiting for the refill and exchange location might be any gas station.

[Sponsor]

[tombogan03884]

It's dead.
It's cooked.
It's free.
Shut up and eat.
Here's more potato salad.   

[Timothy]

It's dead.
It's cooked.
It's free.
Shut up and eat.
Here's more potato salad.   

And a chaser of antibiotics for the salmonella....   

[Badgersmilk]

http://floridakeystreasures.com/category/recipes/iguana/

I'd try it once anyway.  Can't be any worse than eating oysters!  Exactly what was the first guy to eat an oyster thinking when he put THAT in his mouth?