transfer propane into 330 gallon home tank

[romeo2012x]

I bought a new 330 gallon propane tank for my house and local propane companies won't fill it unless it has propane in it. The only way they will is if they do a complete system inspection which I'm fine with them doing because I everything is okay but they don't have time to do it so I can't get the appointment scheduled. I'm wondering if it would be possible to transfer propane from 20 lb cylinders into the tank so that I could call one and tell them to fill it because I'm low rather than telling them it's an empty tank that's never been filled.

I'm familiar with safety issues and am experience with transferring propane as far as filling 1 lb bottles and I have transfer tubes that would connect the two. Would this work? I figure if I was to empty a few 20 lb cylinders into it enough to put something on the gauge I would be okay. I just want to buy a load of propane so I can run my furnace.

 

[enordy]

I think you would want to properly purge the new 330 before having them do a fill, otherwise you run the risk of moisture and air contaminating your system. New vessels are often transported with some pressure in there, along with whatever else (think water vapor).

I believe they usually bleed out any pressure in the new vessel and fill it to 10-15 psi with propane vapor, vent to atmosphere, repeat a couple more times.

 

[ABMax24]

As above. They want the tank purged prior to filling, mixing air and propane in an enclosed container is a bad idea, being the reason it is purged out.

 

[coaly]

Only trained personnel or those familiar with propane gas in vapor and liquid form should transfer LP.
Purge new ASME tank with vapor down to atmospheric pressure at least 3 times to deplete oxygen in tank. It’s nice to have a 10 lb. pressure regulator, but you can guess bringing it up to about that much pressure. Every time you pressurize and let out, you are removing 1/2 the non-LP vapor, wether it be air, hydrogen, or an inert gas in tank.

After depressurizing new tank through service valve, connect DOT cylinder to valve, and with cylinder upright, pressurize a minute or so and close valves. Disconnect line to leave LP vapor out of tank. Repeat 2 more times. Affix LP warning label on tank. This is a 1075 label that should not be on a new tank that has never had LP in it. This also tells a propane co. there has been LP in the tank. Most LP filling stations have them if you ask.

How many 20 lb tanks do you want to put in? This is called drifting. Same principal as filling a portable torch cylinder with fluid from an upside down cylinder.

You will need a hog tail, which is a short line that has a POL fitting ( the left hand thread that fits tanks and cylinders)on each end. (You need this for purging as well) Normally a pig tail is used from tank to regulator, POL X inverted flare. This is a hog tail for tank to Tee POL X POL when multiple cylinders are connected.

If full 20 cylinder is in the sun, it may have enough pressure to easily dump into tank. The first few will drift in easily. As the ASME tank comes up to pressure, it becomes harder to drift fluid from a full cylinder into it. The tanks equalize in pressure and fluid drops slowly in. The colder outside, the slower. Connect cylinder to line with POL end. Turn cylinder upside down and connect other POL end to tank. Open valve on ASME tank. Slowly open valve on cylinder. Liquid LP will rush into tank with the lower pressure. It is all about equalizing the pressure between vessels. Liquid will flow from the upside down cylinder easily at first. Once pressurized, warm water or warm cloth can be put on cylinder to raise pressure in it. You will hear the liquid moving through line into tank. Don’t touch the copper line, it will get extremely cold. Gloves are a good idea. When cylinder is empty, turn cylinder valve off. Wait, or put warm water on line to build pressure to empty line into tank. Close tank valve, remove line. Use gloves, liquid could still be at connection. It will give you chemical burn freezing skin on contact.

This is normally done with a 100# cylinder into a tank on site until a bulk truck can get there when a gas man is on call overnight on a emergency out of gas call. Drift tanks are made with a liquid pipe going to the bottom so they do not have to be inverted. Painted red to differentiate a liquid outlet instead of vapor.

Bulk truck will fill through a larger port for hose. DOT Cylinders are filled this way through service valve with pump.

While a filled propane cylinder is upside down, the relief valve is not in the vapor space where it must be at all times. Drain cylinder immediately, do not allow in this position longer than necessary. The relief valve would release liquid, not lowering the pressure in the vessel as it should.

When transferring liquid from one tank to another, a transfer pump is used. It doesn’t pump liquid from one to another. It removes vapor from top of the low tank and pressurizes it into the top of full tank. This unequal pressure allows fluid to move from full tank to empty tank through a separate liquid only line. Heavy rubber gloves are used dealing with liquid propane at all times. Removing these lines or hoses, you have a full line of liquid released.