That little dude is cool! Gives me an idea...
how do u cut that with out blowing it up. a real close friend of mine was a certified welder and was working on one of those it blew up killed him and 4 others in the shop.
so ive never touched one of those. they (the fire department) said he did everything right but that it was one of those times where it just happened.
Pressure vessels need a bit of respect but they are not magic, if you do everything right there is very limited risk of any harm. You can't "do everything right" and still cause a massive explosion. Unless it was a very different sort of job he was doing than simply scrapping an empty tank.
I've cut a fair few of these up, I was curious about all the rumours about large explosions and used to be into combustion cannons so obviously I tried it.
I filled a 13kg tank with water to determine the volume and injected a stoich mix of propane and ignited it from a distance. WHAM, but no shrapnel, no damage to the cylinder.
I did the same with a random volume of acetylene (after clearing the fumes out with an air line). Big bang, bit of a flame out of the front, but no failure of the cylinder, no shrapnel, no death and destruction.
Conclusion I came to is there is no chance that a cylinder
with the valve removed creates a danger of a large shrapnel causing explosion. You ARE at risk of losing your eyebrows if you've already cut a bit of a hole in it though.
I think any large explosions caused by similar circumstance are due to people weighing into a full or still pressurised cylinder with a torch with no thought to emptying it, perhaps a mix up of tanks or something. Filling it with water and closing the valve could create a steam explosion too.
That said I fill them with water then drain it back out anyway to displace any propane to avoid losing an eyebrow or 2. Probably the riskiest part of this is opening the valve and releasing the residual propane.