Butane/Propane ???

[ytre]

Hello folks, Ive 2 gas cylinders and gonna start my first project, a woodburner. 1 cylinder is propane and the other butane, is one more volatile than the other?, ive vented them over a few days and filled with water and emptyed them several times.
Should i fill them with water when cutting? Any advise greatly appreciated.

 

[brightspark]

Hello folks, Ive 2 gas cylinders and gonna start my first project, a woodburner. 1 cylinder is propane and the other butane, is one more volatile than the other?, ive vented them over a few days and filled with water and emptyed them several times.
Should i fill them with water when cutting? Any advise greatly appreciated.

propane or butane only diffrence is propane a hotter gas . makes no odds when cutting them up . just fill with water after venting and cut away. ps dont get wet

 

[rtbcomp]

............ ps dont get wet

Don't get electric power tools wet either

 

[Douglas]

Yeah likewise, depressure, fill with water and chop 'em up.

Here's some of the techy stuff behind gasses and such other stuff.

They're all commonly known as LPG (Liquid petroleum gas) which is a broad generalisation for hydro-carbons which vapourise at atmospheric pressure. It depends on how many carbon atoms are attached to the singular hydrgen atom at mollecular level. In refining terms they're classed like this and are known as C1, C2, C3, C4 etc. In old refining terms they were 'white oils'. I'm a little rusty as to which is which now but I think it goes something like C1 Ethane, C2 butane, C3 propane (methane's in there somewhere too) etc with C6 being gasoline/petrol (I think!). At around C4 or 5 the oils become stable at atmospheric pressure and don't vapourise so, C6 petrol, then nahptha then diesel which we know are used in the automotive industries for fuel due to there explosivity. I think, although I'm no expert, that after this the percentage of carbon to hydrogen atoms is such that they are no longer explosive but are used for lubrication etc. The refiners then have to heat what's left up to something like 700 degrees under an almost pure vaccuum for it to liquify and they turn that into coke which is almost pure carbon (think air arc carbons), at around 99.8% purity. They also sometimes run this stuff through a 'cracker' which smashes all of it up again so that they can ring out any goodness that's left. The biggest problem for the refiner is sulphur which has to be gotten rid of for legal reasons and they don't have a use for sulphur so they bury it in the ground.
If you can come up with something that can be done with the stuff, you'd be a very rich person indeed.
Hope this is enlightening.
Doug

 

[CRS51]

Hi, when we made our two burners (49kg) size, we vented them and then filled them with water and used petrol stihl saw to cut them. PS you won't get rid of the gas smell until you light it for the first time.Cheers Chris.

 

[SilverhillForge]

You've done the right thing there for sure Ytre. I used to work at the Flogas cylinder refurbishment plant up in Staveley and quite simply, when a cylinder was too far out of test date or too heavy for standards, the cylinder was linked to a simple vent-stack apparatus (read; regulator leading to a vertical pipe which vented gas to the atmosphere) whereby it was left venting until 'flat'. The valve was removed with a spanner, and the cylinder was sent to the scrappers.

The smell (methyl mercaptan) which is the stenching agent added to the gas, like Chris said, will burn off after a while. It's a hellishly oily substance and if you're unlucky enough to have a particularly old cylinder, it could contain as much a 15-20% of this stuff. I'd suggest wearing disposible clothes unless you like smelling like a field of rotten cabbage!!

 

[pidgeon chit welder]

You've done the right thing there for sure Ytre. I used to work at the Flogas cylinder refurbishment plant up in Staveley and quite simply, when a cylinder was too far out of test date or too heavy for standards, the cylinder was linked to a simple vent-stack apparatus (read; regulator leading to a vertical pipe which vented gas to the atmosphere) whereby it was left venting until 'flat'. The valve was removed with a spanner, and the cylinder was sent to the scrappers.

The smell (methyl mercaptan) which is the stenching agent added to the gas, like Chris said, will burn off after a while. It's a hellishly oily substance and if you're unlucky enough to have a particularly old cylinder, it could contain as much a 15-20% of this stuff. I'd suggest wearing disposible clothes unless you like smelling like a field of rotten cabbage!!

Methyl mercaptain is that the flammable oil residue that can bung up regulators on butane cylinders ?

A good friend of mine Trevor Lowe used to be the sole importer of methyl mercaptain odour source for natural gas ( ?) from Israel and one day had a cylinder with a dodgy valve , it fell over making for a leaking cylinder which set off every gas monitoring alarm for some 130 miles in a Dairylee shape cheese segment down wind .

Apparently loads of emergency services turned up one Sunday as they were sitting down to lunch .

 

[SilverhillForge]

That's the very same stuff. It's been responsible for similar incidents all over Europe. It can also be a real PITA for those who use LPG for automotive/FLT/marine applications.

 

[ytre]

You've done the right thing there for sure Ytre. I used to work at the Flogas cylinder refurbishment plant up in Staveley and quite simply, when a cylinder was too far out of test date or too heavy for standards, the cylinder was linked to a simple vent-stack apparatus (read; regulator leading to a vertical pipe which vented gas to the atmosphere) whereby it was left venting until 'flat'. The valve was removed with a spanner, and the cylinder was sent to the scrappers.

The smell (methyl mercaptan) which is the stenching agent added to the gas, like Chris said, will burn off after a while. It's a hellishly oily substance and if you're unlucky enough to have a particularly old cylinder, it could contain as much a 15-20% of this stuff. I'd suggest wearing disposible clothes unless you like smelling like a field of rotten cabbage!!

Thanks folks for all the info, how long should they vent for silverhillforge?

 

[SilverhillForge]

On the vent stack, we'd vent them for about 20 minutes or so. Although a lot of the time taken to vent would be dependent upon the amount of gas in the bottle based upon the weight of the bottle as measures on scales, minus the tare weight stamped on the data plate on the cylinder. For your pruposes, I'd estimate that if you attached a regulator to the bottle and left it overnight, the pressure in the cylinder would be pretty much 'flat'.

My advice is to remove the brass valve in the top of the cylinder before cutting. By doing this you'll get an idea of the remaining pressure. If you've filled the bottle with water, the pressure should be negligible or even non-existant, so no worries there. Sounds like you've taken the same precautions that I'd have taken so far.

 

[ytre]

Many Thanks, ive removed the brass valve a few days ago and its been venting for a few days, filled with water a few times and emptied. Is it reccommended to fill them with water and then cut them full of water

 

[SilverhillForge]

Never got as far as cutting myself. But with the valve out (ie. with a huge hole in the top) and being full of water.............let cutting commence. Just keep the electrics dry :-)