LP tank valve removal UPDATE

I realized last night there was still some liquid left in the tanks. I bled that off, and left the valves open overnight.

Note: Don't get that liquid on your skin. Not so much for the obvious frost bite hazards, but because of that nasty ethyl mercaptain odorant that is in the gas that will absorb into your skin. My wife was not happy with me last night. My hands still wreak.

This morning, I chained the tank to a solid post, and used a load binder to tighten it up so it wouldn't move. I lucked out in that I managed to find a combination of links that allowed me to get the chain very tight, but not to the point of crushing the tank.

I closed the valves, and used a propane torch to heat the bung until it was too hot to touch.

I leaned on the handle of a 24" pipe wrench, and the valves backed out easily. (they are RIGHT handed, by the way)

There is a thread seal dope on the threads that hardens as it cures. As many people have told me, this makes the valves virtually impossible to remove. Heat softens the dope, and makes it easy to remove the valves.

Now, before I get flamed for applying heat to the tanks, let me explain some logic here.

First, although the tanks were full of LP vapor, there was no liquid, and there was no pressure in the tanks.

Second, the valves were closed, so no gas was escaping and available to ignite.

Third, the inside of the tank contained 100% LP vapor. This is not explosive. The explosive limits for LP gas is between 1% and 10% in air. Had a fracture occurred, the flame would not have burned into the tank. The flame would have only occurred where the escaping gas was mixing with air.

I got advice from people saying to pressurize the tank with air, and bleed it off a couple of times. This could have easily left me with an explosive mixture inside the tank. Leaving it full of 100% LP vapor was MUCH safer.

Fourth, this was a 100 pound LP tank. Heating the bung is not going to heat the gas inside to any significant amount, and certainly not enough to risk a pressure explosion. In fact, when the valve was removed, there was barely any hiss of gas escaping.

Dave

Reply to
Serial # 19781010
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You were lucky Your arguement about it being 100% vapor sucks wind after leaving the valves open overnight. Next time before we read about pieces of you being found elsewhere quit screwing around and fill the tanks with water.

Reply to
Beecrofter

Better you than me, I already went through having a pressurized

-non-flamable container go off on me, and certainly would not want to even consider a container that held propane no matter how small of ratio of gas to air it had. Its certainly not worth my life or limb to take such a chance.

I have taken them out before and have never used heat. Visit my website:

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expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy.

Reply to
Roy

Luck had nothing to do with it.

First, LP gas is more dense than air. It isn't going to leave the tank of it's own free will.

Second, even if some air had managed to get drawn back into the tank, it certainly wouldn't achieve the 90% air required to make the mixture explosive.

Third, how would you fill a propane tank with water with the valve still in it?

Dave

Reply to
David A. Webb

How can you compare the danger of a pressurized container to a non-pressurized container?

How dangerous would a non-pressurized container be, if it's contents were not explosive?

Dave

Reply to
David A. Webb

Hey Beecrofter,

And leave the valve closed? Now that IS scary. The steam pressure will kill him long before there is enough heat applied to loosen core. Or the core loosening will cause the steam to blow it out!

Take care.

Brian Laws>> I realized last night there was still some liquid left in the tanks.

Reply to
Brian Lawson

Just make sure you wash it out with Chlorine (Chlorox) to kill most of the ethel mercaptan (stink) or you'll smell it for a very long time.

Also ethel settles out , there could be a pool in the bottom of an old tank. It should be dumped before washing. Don't spill it or you could be sorry.

Reply to
Mark

You need to learn about diffusion.

Reply to
Richard J Kinch

I turned the tanks upside down and vented off the last bit of liquid LP... and got the stink all over myself in the process.

So... bleach will kill the odor?

Dave

Reply to
David A. Webb

Okay, I'll concede that if I left the tank valve open long enough, air would eventually replace ALL of the gas through diffusion. Between now and that point in time, there would be a point where the mixture would be explosive. However, the passageway through the valve is pretty small, and as I stated before , LP vapor is heavier than air. With the tank all but sealed, and no real movement of the vapor inside the tank, the diffusion would even slower than if something was stirring up the gas inside. Overall, the diffusion would be a very slow process.

I will also concede that based on this, odds are the gas inside the tank wasn't 100% LP vapor as argued by a previous post. So was it

99.9%? 95%? As stated, the LP vapor has to get down to 10% before it is explosive.

So in reality, how long would it take for air to diffuse into the tank through the tiny valve opening, and replace 90% of the LP vapor?

Maybe in my lifetime, but certainly not overnight.

Dave

Reply to
David A. Webb

From a previous post of mine: "I poured in about a cup of bleach, sloshed it around, let it sit, sloshed a few more times. After about 24 hr., I drained the bleach, rinsed with a little water and filled with air. The air was totally odor free. Well, it smelled a little, more like paint thinner than anything.

Note - I did this with the valve on, it would be easier with it off, but probably not worth the effort."

Reply to
Bob Engelhardt

How exactly did you determine it was at the concentration level you stated? Visit my website:

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expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy.

Reply to
Roy

Which concentration level? I initially stated that it was 100% LP vapor.

Then someone argued that because the valve was left open overnight, it couldn't have been 100% LP vapor. So I conceeded that the LP vapor concentration in the tank might have been slightly less than 100%, but not much. Regardless of what it actually was, there was no way it could have been down to the explosive range.

My initial statement was based on the fact that there was liquid LP (I know it is redundant) and any tiny bit of air that might have been in the tank with the liquid would have been purged when I vented the tanks.

Once the liquid was evaporated, and the pressure inside the tank dropped to zero, it is safe to assume the only thing left in the tank is LP vapor.

Had there not been any liquified gas in the tank, I wouldn't have had any way of knowing what kind of mixture was in the tank, and I wouldn't have attempted to heat the bung before doing something to make the situation safer.

Dave

Reply to
David A. Webb

"Kill" is too optimistic of word.

It will decrease the stink substantially under best of circumstances.

HTH

Reply to
Mark

Glad you did this. Ethel M will be mostly dissolved if there is liquid.

So turning it upside down and blowing off the last of the propane was the best you could do to get rid of the mercaptan.

No fireball, your still alive and unburned, Cool.

I would have found a fitting to plumb it into a flex pipe and then piped it into a piece of black pipe and had some Fun. Would freak out the Neighbors. ;)

Don't try this at home, I'm a trained Professional ( Woof! ).

Turning the tank upside down and blowing it off was the best thing you could do to get rid of the stink.

Reply to
Mark

Snip

Snip

When I worked for the gas company, we had a foreman who would fix gas leaks in the pipeline by arc-welding them while the gas was escaping.

I don't know if OSHA would allow such a thing, any more.

Orrin

Reply to
Orrin Iseminger

how about the guys each year that take an old 55 gal.drum at work and think they gonna cut the top off to make a nice trash can/burner with it and it blows up on them..... too close to an old propane tank for me to mess with.... i would just leave the tank alone and go with something else that cost a few bucks to maybe save me from flying in the air when it blows..... i know it is not suppose to blow, but i remember seeing a PVC pipe that was used for water on an a/c unit in an office building that expaned from its normal 3 inch size to about 6 inches and exploded during the night and left this 4 story bank building full of water all the way down to the 1st floor which was the bank office.. about 4 inches of water on the floor...... the manager was on the phone talking to one of the officers and was telling him what happened.....about 10:00PM.... then i guess the officer told the manager that this does not happen.... the manager was hollering into the phone that i know it does not happen, but i am looking at it....... needless to say they were told to tell the employees to come to work in blue jeans the next morning....

Reply to
jim

To get the stink off of YOU (& your clothes) light a smouldering smoking fire in your gravel driveway or yard and walk thru the smoke. It will kill the smell good enough for your wife's nose.

Reply to
Nick Hull

If you let the LP vapor bubble out thru a jug of water, if there is any suck back it will be water.

Reply to
Nick Hull

I find that about ten air purges over a month does a fair job of getting most of the mercaptan out. Gerry :-)} London, Canada

Reply to
Gerald Miller

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