Lpg tanks

[1.8T]

Im interested to see whether anyone here can explain this, recently i removed the sender from what i thought was an empty lpg tank in order to make it safe to dispose of, no hissing of gas as the sender was removed but after i removed the sender i peered into the tank and could see liquid at the bottom which was bubbling away, any ideas why it was bubbling yet no pressure?

 

[waddycall]

Run?

 

[1.8T]

Well i did quickly insert the garden hose & make a hasty retreat

 

[WorkshopChris]

Was it a very cold day? the gas in a butane cylinder will not flow as a gas, it turns in liquid in winter.

 

[waddycall]

How much was in there? What sort of depth?

 

[1.8T]

Not really it was a couple of weeks ago, this was the second of two tanks, the first did have some gas in it but when emptied had no liquid

 

[1.8T]

It was probably a couple of cm's in depth in a tank roughly 50cm by 35cm

 

[CompoSimmonite]

Might have been water.

 

[1.8T]

Water that bubbles vigorously?

 

[WorkshopChris]

Probably just the residual gas boiling off and evaporating. Depends what was in the lpg mix.

 

[colnerov]

Hi, The ambient temperature was higher than the boiling point of the liquid so it was boiling off. Once it's done that there will still be gas in there because the gas is heavier than air, if you want it out turn it upside down. But make sure there are no drains or basements about or any low areas where it will collect and catch the unaware with a discarded cigarette.

Colin

 

[the snooper]

Probably just the residual gas boiling off and evaporating. Depends what was in the lpg mix.

As Chris says, the liquid boils / evaporates at a low temperature if it didn't you wouldn't get gas from the cylinder, only liquid

 

[normspanners]

I have told this before, once in very cold conditions at my mums I removed the tap from a butane cylinder thinking it was full of water to find it actually was lpg that was too cold to escape I resealed and screwed the tap back in, then took it up stairs, ran hot water over it in the bath for ten minutes and refitted it and hey presto the mobile heater lit !!

 

[Screwdriver]

Don't try this at home folks but I once emptied a tank of Calor gas out onto my rear pavement

It turned into a sort of slushy snow then just sat there in a puddle.

I couldn't resist...



WHOOMPH


Goes up like a nuclear bomb. Big mushroom cloud of smoke and flame. If you do try this (I seriously suggest you don't) I estimate the chance of being killed or seriously injured at about 3:1. That's you, the neighbour, their cat etc. someone's gonna get it.

S.

 

[colnerov]

Oh Hollywood...

Have you ever tried lighting gas with a cigarette? Or petrol?

In the films, someone turns on the hob and throws a cigarette in the room and the whole town explodes - or they tip petrol on the floor and throw a cigarette into the puddle and the petrol station explodes taking the nearby nunnery and kitten sanctuary with it.

Do you have any idea what happens in reality?

Nothing.

At all.

Well, a puddle of petrol will quite efficiently extinguish a cigarette...


Lighting a cigarette (with a match/lighter, not like with a car cigar lighter) on the other hand...

Hi, I do actually know. You're right if a cig or other flame was thrown in the tank or a puddle it would go out because the atmosphere is too rich. But as the gas or fumes spread out it is diluted in the air until such time as the mixture is right and then it becomes explosive just like in an engine. We were taught this on the ADR course for tankers. Why do you think when there is a fuel tanker spill the emergency services go to great pains to protect drains and have a quite large exclusion zones?

Colin