Propane transfer

[bandmiller2]

Not exactly a woody question but are any of you fellas well versed in handling propane. I have a horizontal propane tank designed for use in a vehicle and it has 25-30 gallons of propane in it. I would like to transfer it into 20 lb bottles. Is there a way to do it safely. Can I pump it with a small hydraulic pump, I can draw liquid from the tank. Would I be able to do it by gravity.?? Thanks. Frank C.

[beenthere]

I'd expect it to take a liquid gas pump (not hyd. pump), but for sure I do not know.. might google it.

Liquid can be moved by decreasing pressure in the receiving tank, but think one really needs to know what is going on and how the tanks are set up (if the 20#'rs even have a bleed valve.. don't think so).

Then there is this YT...
https://www.youtube.com/watch?v=XjMyveIvAAk

That shows the method of cooling the small tank for gas transfer. Also points out the bleeding valve I thought was usable. But doesn't work if the pressure in both large and small tanks are the same. If on a sunny day, maybe just throw a black tarp over the big tank to cause it to heat up a bit.

[pineywoods]

Multiple questions, multiple answers...Can it be done ? yes, is it worth the trouble ? probably no...Best way would be a pump pumping liquid, don't know about the hydraulic pump. Gravity, no, but pressure yes. Connect the 2 tanks with a hose carrying liquid, small tank upright. Open a vent valve on the recieving tank to vent off a small amount of gas. Downside, you can't drain the big tank and you won't be able to completely fill the small one. Don't even think about doing this in an enclosed building, best in an open field with a gentle breeze blowing. Be aware that propane gas is heavier than air, and it will run and puddle just like it was water. My recommendation would be hook the big tank to a grill and break out the steaks....

[Corley5]

My recommendation would be hook the big tank to a grill and break out the steaks....

X2

[r.man]

Frank I don't see why it couldn't be done safely by a careful person in an open area. Receiving tank upright, donating tank so that the liquid is coming out, donating tank warmer than receiving. When doing freon the donating tank is sometimes slightly warmed with warm water or the receiving tank can be cooled with cool water if a pressure differential is needed. You would need an indication of weight in the receiver and I wouldn't try to make them full, maybe two thirds. I would avoid pumps because of the whole explosion issue. A bathroom scale would work as an indicator and I think it would be prudent to put up no smoking signs.

[beenthere]

r.man
You must have watched the video I linked.  ;D  or maybe you made that video... 

[r.man]

Beenthere, didn't look at the link until just now, not me. I have two brothers in HVAC and I was remembering conversations with the younger on freon tanks and transferring gas or liquid depending on what is needed. I have also seen him add gas or liquid to reefer units and storage tanks.

[Gary_C]

Can I pump it with a small hydraulic pump, I can draw liquid from the tank.

Not safely without the right equipment. The pumps that are made for pumping liquid propane have a mechanism for bleeding back vapors to keep the pressure from building in the receiving tank. Without the right pump, you would be in big trouble.

By gravity, no.

You can bleed fill those 20 lb. tanks if you are drawing liquid from the tank, but you need to know what you are doing. It's best to start with no pressure in the 20 lb. and make your connections and open the bleed fill valve (sometimes called the 80% valve) and let it fill till you get liquid spitting from the bleed fill valve. With the OPD valves it takes a long time. The internal float mechanism that prevents overfilling also slows down the flow but it prevents amateurs from overfilling the tank.

With the old style valves it's faster but you have to be careful to not overfill the tank. When you don't know what you are doing, it's also critical for you to do the filling on a scale and know the tare weight of the tank. You never fill to more than the tare weight plus 20 lbs.

Bleed filling is somewhat wasteful as you are venting vapors but it's the only way to move liquid safely without the proper pumps and equipment.

[bandmiller2]

Thanks guys its pretty much what I figured just wanted to make sure I wasn't missing something. I transfer CO2 to smaller bottles and its the same only propane burns. Frank C.

[1countryboy]

LP gas is nothing to mess with UNLESS you have experience.  It is not worth it for 20 gallons.  A special LP gas pump is needed. $400+ for a hand pump.  If you are serious call the propane dealer and they can pump it for a minimum of $100.  Not worth it. 

[sawdust]

May not be the smartest way to do it, I have moved a lot of propane using vents. Use the liquid line off the big tank, (or turn it upside down) open the vent on the receiving tank. Temperature is not relevant. I also put a hose on the vent to carry the vapour away. A good windy day is best.

-40 is good too! then it is liquid anyway.
You can actually carry an open pail of liquid propane. Just to say you did it.