Large propane tank purging

[Hossfly]

I purchased a 1000 gallon used propane tank old and has good data plate. Tank has been sitting a while. Has no odor, or smell of propane,but had about 2# pressure when I got it.
So my question is, would the tank stand to be evacuated to deep vacuum, would it implode or collapse with a deep vacuum like that. Cheaper to evacuate to get air and moisture out than to purge with 18 gallons of propane, the way some companies do it.
Tank looks good and sound, no dents or pits, normal looking horizontal above ground tank. Purchased for storage of fuel price in summer being a lot cheaper.

[lightman]

The cut open bulk tanks that I have seen are thick enough that a vacuum would not collapse them. Could the purge be done with compressed air?

[country gent]

Purge with air pressure or maybe nitrogen to remove moistures then compressed air to remove nitrogen. Ideally in one end out the other push pull everything out. Run air in the tank thru fill to set pressure then out another opening maybe a valve fitted in place of the pop off valve, do this several times. 1000 gal tank is going to take a lot of air compressor to reach 10-15 lbs pressure even.

[Hossfly]

I’m thinking it would take a good vacuum. The large Freon tanks would take all we could pull with our vacuum pumps. Some times we would hook up and let run all night. Shaped like same but were up right, still with domes top and bottom. I remember 2’’ vacuum = 1 psi so gauge reading would be only = to 15 psi if reading 29.92 “ on manifold gauge. Think I might just hook up pump and leave the area in case it implodes I won’t be around close. I know 55 gallon barrel @ 15” would collapse totally.
But they were very thin.

[cas]

I'm a little confused... what are you putting in it?

[Hossfly]

Getting it ready for propane storage next summer when fuel is cheap. Last year had major propane co. call and price was $1.00 per gallon, and I didn’t have room in any of my tanks for it. Now I’ll be prepared.

[Jeff Michel]

Call the propane vendor, they'll have the ability to do an inspection , might not need to do anything outside of a pressure check. The #2 registering on the gauge might not mean anything, might just need replaced.

[.429&H110]

I once worked propane service, yes you can deep vacuum any propane tank. Don't use your best pump, change the oil in it when done. You will not get deep vacuum on a dirty old tank, but you will get more air out than purging. When you pull propane out with the vacuum pump, the pump motor will light the discharge handle, so tape a long hose on and don't fill the neighbors backyard with a bad smell. The wind is your friend. I would rather vac than purge a tank, it's cheaper. Be very sure there is no water at all in that tank or the regulator will freeze. There may be heavy ends, don't get that oily stuff on your boots. The liquid withdrawal valve probably leaks, most do. The relief valve may not work, or leak. Do not put any tank on asphalt pavement or you will test that relief. Lally columns set three feet deep will keep the kids from driving into the tank. Be sure the propane company will fill the thing when you are done. Most will want a gascheck check, the check you write to get checked. For small money, a propane company might swap out for a new tank. They like big tanks.

[marlin39a]

Did you open the spit valve to check for pressure? If you hook it up, your propane company will have to pressure check the system. What's the date of manufacture? I would replace all plumbing before going online.

[Hossfly]

.429&H110 i have a small vacuum pump I plan on using for this, its 5 com and would very slow, but will pull down to around 300 microns so it should do for dehydrating any moisture present. Good idea on putting hose on discharge of pump to get out of the area of shop, no neighbors around 1/4 miles to one tho, can’t smell any odorant but could be still flammable. Thanks that answers my question mainly about tank colapsing under a deep vacuum.
Marlin39A yes I’m going to replace all plumbing valves and relief also the dip tube for filling my extra tanks. Tank date is 1965 good data plate with serial # readable. And yes they will charge 59$ for leak test rules is rules and I follow the rules.

[725]

I used to just fill them up with water to purge contents. seal the bottom drain - fill it to overflowing - voila

[JSH]

After having hauled propane a day or two and delivered to the home, it was always to my understanding the only reason to put a vacum on was to open the pores in the steel in order for the oderant to absorb.
There should be a liquid and a vapor fitting on the tank. You should, but don't have to hook them both up. When you are pumping the liquid in, the vapor pressure will return to the truck.
All you are burning on most homes is the vapor off of the top any way.

What ever you do not put water in it, that is silly.
If it has been sitting for a long time with little or no pressure, changing all the fittings NOW could save you in the long run. Beware some tanks have liquid and vapor discharge fittings. You don't want to hook a liquid valve up to a vapor regulator. It will freeze it up and not work.

Folks want to make a big deal out of these as far as working on them. A small amount of common sense goes a long way. I have worked on hundreds if not into the thousands of LP tanks from 3lb bottles to 20K tanks. They all work the same for the most part.

[.429&H110]

I worked out of White River Vt half my life. One highpoint was the competitors had a 1000 gallon up on a sawhorse painting it in their shop. Tank rolled off broke the valve and lit. Call came on my radio, so we all gathered across the street to watch the 20K tank relieve. Fire department got enough water on it so we didn't get the big blivy. Some small ones, though. Hats off to a fire dept that will show up to a propane plant fire! Noone hurt, some appliances lost, so our whole showroom got a markup. I like propane service, A/C pays better though.

[Hossfly]

Yep i found out that 1000 gallon tank weights right at 2000# empty, that’s why mine is setting on concrete blocks and not cinder blocks, big difference in weight empty to 80% full.

[cas]

Okay I'm still confused. :p

If it's got propane in it... and you're going to put propane in it... what's the problem? :)

[Hossfly]

It doesn’t have propane in it, just wet air from sitting for long time in someone’s yard. I’m cleaning it out to get ready for future storage of summer price propane storage. I pressured it up today and found multi-purpose vapor vent valve and large fill valve double checks are leaking at 10# PSI. Will need kits to rebuild these and get leak free before pulling a deep vacuum to try and get any moisture and all air out before filling with propane vapor.

[.429&H110]

Yessir! get her done! If only more pilot lighters were as good as you. Had a lot of temporary rubber air hoses hooked to propane "Until I can get the ditch dug". A construction site in winter went cold, so I showed up, trudging through the snow my boots were smoking. Lull ran over the rubber lines, under the snow...I was wading through liquid propane under the snow. The fire dept -love those guys- washed all the snow away, no more propane. One spark and I woulda been lighting pilots in Hell, wasn't saved way back then. Lord smiled, I wasn't smoking a cigarette. Just had put one out.

[Hossfly]

I lit an exhaust from a large vacuum pump once from a decaying absorption unit, didn’t know it was full of hydrogen, bout messed my britches when a 6 ft. Flame appeared and went back toward pump
LOL didn’t do that again.

[Hossfly]

Got leaking valves rebuilt and installed, pressured to 17# psi, ran out of day light, and air. Will start again to reach 100# psi, then blow pressure and evacuate with vacuum pump to rid of all air and moisture. Then should take about 4 gallon of propane to bring up to atmo. Still need a 1st stage regulator and will be ready for storage.

[JSH]

FYI, if you are putting air in it from a compressor with no air dryer, you are putting moisture in it for sure.

[lightman]

Not to hi-jack the thread but I've seen those larger tanks cut up and used for some useful things. Our Scout troop had an end cut from one that we used as a base for fires. A farmer buddy has one that we use to cook Crawfish in. I expect a cut off one smaller than 1000 gallon would make a good smelting pot. Once the ends are cut off they make good culverts. Sorry for the hi-jack!

[Hossfly]

That’s ok I saw a 250# tank repurposed for a bar b q commercial and was mounted on a trailer axle , nice and portable. On my large tank , after extensive leak testing, hooked up vacuum pump with long water hose for exhaust. Good so far, 12:00, 5 hours later returned to only find down to 10’’ Hg, upon further evaluation found the large fill valve that wouldn’t leak @ 100 psi was sucking in air. Used some 515 by Locktite gasket eliminator and some tight fitting dust caps, sealed and restarted evacuation again this morning, we will see.

[Hossfly]

Good news, got all input valves sealed with gasket sealer and dust caps and teflon tape pulled 7 hrs vacuum down to 29+ on gauge set. Noticed liquid H20 at hose fitting @ pump discharge, oil very cloudy when changing oil in pump. Will let set and check pressure in am. Have to get my old wet bulb device out and test to see if dry.

[Down South]

If you find propane at $1.00 a gallon, you do well. They had a price war here in September and the best I could do was $1.75 per gallon. I filled up a 500 gal and a 120 gal tank.

Oh, BTW, I wish that I had a 1000 gal tank.

[Hossfly]

Next time they call with that price i will have the capacity to say filler up.

[samari46]

maybe I'm overly cautious but would remove all fittings like guages and stuff that will not be used for a water test. Introduce the water from the bottom of the tank and when filled keep it running to make sure you are getting a good overfill.Then when satisfied that the tank is/gas been completely filled drain out the water and use compressed air to remove any water clinging on the sides and bottom. After that a good visual inspection with a high powered light source to check on the internal condition of the tank should be performed. Frank

[Hossfly]

Up date; pulled vacuum for 2 days and am sure all trace of water and gas is gone. Hurray, hooked up 100# tank with regulator and took about 1 hr. To bring pressure up to above atmospheric. So now ready to clean and paint install skids and get set up in area of other tanks, fixin to get cool next week.

[.429&H110]

Break the vac with propane. Just right. The air is gone and might be some moisture clinging on but the propane will absorb it. The other way is put in five gallons of propane, and flare it off, three times. The air rises to the top and escapes with the bad smell. This purge idea will not get all the air out, but it works. Boss has to buy 15 gallons of propane for each tank, and a gallon of methanol and an hour of my time. Vac a new dry tank, and life is good. Same idea is used for refrigeration. The steam tables are your friend.

[Hossfly]

.429&H110 that’s what I’ve been doing for last 45 years Heavy ref. Large chillers and skid boilers so been evacuating large vessels. This is first propane tank this large I’ve had to deal with tho. Looked inside when had valves off didn’t see any liquid water inside, some trash like substance in very bottom, not much tho. Got valves tight and pressured to 100# all good, took 2 days to get to point i thought was good vacuum few bubbles out pump exhaust. Now setting with a little pressure to keep anything getting in.

[.429&H110]

The trash in the bottom is odorant mixed with junk that tried to seal the delivery truck plumbing. Thread goop, teflon tape, lost o-rings, grease from the hose reel. I have found cigarette butts, rust, pop-tops, mice, dirt... Junk can stop up the liquid withdrawal valve and cause a very long day. Taking vapor from the top leaves all that in the bottom.

[Hossfly]

Update on large propane tank. Been a while since I started this thread, so got the 1,000 gallon used tank leak tested, evacuated, pressurized to
15# and let sit over 3 months. Still at 15# dragged to area of intended operation, cleaned up pretty and painted silver. Piped into system manifold. Called around for price’s locally, in August prices ranged from high of $2.59 to low of $1.45, bring it on. Bought 300 gallons first time waited till September and price still low bought 300 more, I wanted to make sure all was working before getting a lot. Now have enough to last till next August, with this large tank and the 250 gallon as reserve, the 150 gallon tank is now sitting at old shop for melting WW and sheet lead. Now I can fill my small tanks from large one at lower cost. Thanks for all your input on this project Hossfly

[10x]

The whole point of purging is to get oxygen and moisture out of the tank so that when you fill the tank you have undiluted propane Filling a propane tank and mixing with air (21% oxygen) under pressure creates a potential problem.
O2 also rusts the inside of the steel tank.

Sometimes the internet is helpful
https://www.google.com/search?q=Purging+1000+gallon+propane+tank&oq=Purging+1000+gallon+propane+tank&aqs=chrome..69i57j0.16947j1j7&sourceid=chrome&ie=UTF-8

[dg31872]

I would find a propane guy that you can work with and follow his recommendations for testing it.
We use a lot of propane on our farm. We buy transports loads at a time. Just got a load last week at .745 per gallon laid-in. A transport is around 9,000 gallons. It is going up.
Normally, best time to fill it is the first of July.
The fact that it was still pressurized is good. Means no rust on the inside.
I think you said it was setting on the ground? Might do a thickness test for the bottom. If it has been on the ground for awhile, there will be rust pits on the outside bottom.
Not real expensive and then you will know for sure. Propane guy can set that up for you.
We bought a 12,000 gal tank couple years ago that had been open. I requested a hydro test (they fill it almost competely full of water then pump air in to the max pressure) and a thickness test. The tank passed both tests, so I could sleep close to it with our worriyng.
Better to spend a couple extra bucks and be safe.

[Froogal]

At one time my propane supplier would not fill a tank they did not own. That company is now under new management so it may have changed.

[Hossfly]

This tank had good paint, rolled it over and found no pits. Cleaned with wire wheel grinder, wiped down with thinner and painted silver. After filling with first 300 gallons, checked temp/pressure , during 100’+ days pressure would get to around 160# in August with sun on it. Now at night and colder weather pressure down around 80#. Dropping thru primary regulator to 9-10 psi. Then secondary regulators to 14” at gen. Set and boilers for 2 greenhouses. Been running great thru generator and boilers flames look good and blue, no hiccups so far,also have 250 gallon in reserve. Also tank is elevated on concrete blocks and level so we can access for cleaning and maintenance. The liquid valve does leak when operated, have it tight right now, and blocked in, when this tank gets real low will pump out vapors with recovery pump and replace.

[drac0nic]

I used to work at a propane plant. You have 2 options:

1-Vacuum purge is how the factory did it when we were getting new tanks in. Totally valid way to go.
2-We would pressurize the tank with LPG then release it 3-5 times. If you have a burn off stack or some other way of getting rid of the propane vapor this isn't a bad way to go.

That said if you had a couple psi in there you're probably okay. I will say that there is somewhat of a controversy in the industry around "odor fade" although I've personally experienced it as well as being able to ingnore the smell. You're not supposed to see either really.

Look for any black crap around the valves and along the welds. If it's got a leak there you'll probably see spots. You can rub your hand on them a bit and you'll smell the oil if it is. The bottom plugs weren't that unusual to have leaking a bit and the gauges were another fairly common spot.. If it's leaking on a weld you can take a punch around the pin hole and "peen" it shut. Seen it done a few times.

ED:whoops way behind the curve reading this morning. Sounds like it got settled out. The liquid valves are indeed leak prone at times. If it has one with the pipe going in to the bottom you should replace it with the "spreader" type when you do. They tend to fill the tank easier because they cool it as they fill.

[MT Gianni]

One local company will not fill a personally owned, non white tank. They require a white finish as identification. That is the only way to find one friends house. If his tank were green you would never see the place. I think you did good, though a 500 gallon tank only gets me from August to February with out a refill.

[Hossfly]

Update on large tank. Started heating season with 600 gallons of propane, and 250 gallon tank at 60%, large tank is down to 10% and will switch over to smaller one tomorrow. Tonight will get to about 29’ and both greenhouses will pull quite a bit of gas. This last storm that took out power for general area and gen set ran for 30 hrs. So that took quite a bit of gas. Called my propane supplier for price and got delivery set up for 100 gallons to be delivered on Monday for $1.50 per gallon. Trying to make it till summer and will buy more. Waiting for pressure to drop so I can change out the liquid recovery valve. I do have a pump out unit to pull out the remaining gas.

[drac0nic]

holy smokes it's 1.50 a gallon in winter? I remember when it was 2.50+ back some 15 years ago!

[Hossfly]

I was surprised also thought they would be at least $2.50. If $1.50 is winter price maybe it’ll get down even lower by summer. Here in Louisiana the winters aren’t very severe. That’s why I bought the 1000 gal. Tank so could buy in summer when it was cheaper.

[6bg6ga]

So my question is, would the tank stand to be evacuated to deep vacuum, would it implode or collapse with a deep vacuum like that.

Absolutely would not implode or collapse. It was meant to take pressure so if it will take pressure it will also take vacuum.

[Hossfly]

Held vacuum very well. Pulled vacuum for 48 hrs. To make sure all moisture was gone, then put positive pressure with propane gas to 15# psi and let sit for several weeks, still held tight. Drug it with my tractor to final spot, cleaned and painted. Called for gas, installed 600 gal at $1.47 per and new regulator. Worked good all heating season, waiting to get all liquid out, then all pressure so can fix liquid withdrawal valve that leaks slightly, but is blocked in for now. Won’t take long tho cause we still got some cold nights ahead.

[lightman]

I was looking for a 20# propane bottle for a member, Tazlaw, and rode down to the river where all of the flooding was last spring. I didn't find Tazlaw a bottle but there are several 250 and 500 size tanks laying in the woods, having broken loose from their attachments and floated away. My buddy, that owns a lot of that property has offered them to me. I was thinking about cutting the end out of one of the 250's and making a smelting pot.

I thought the propane companies owned them but apparently they don't want them bad enough to come after them.

[Hossfly]

Lightman i thing the head thickness on those tanks are about .230’’ thick a little thinner than the shell thickness, would indeed make for a large melting pot. You would need a lot of burner under it, and a good support to hold it up tho.

[drac0nic]

I was looking for a 20# propane bottle for a member, Tazlaw, and rode down to the river where all of the flooding was last spring. I didn't find Tazlaw a bottle but there are several 250 and 500 size tanks laying in the woods, having broken loose from their attachments and floated away. My buddy, that owns a lot of that property has offered them to me. I was thinking about cutting the end out of one of the 250's and making a smelting pot.

I thought the propane companies owned them but apparently they don't want them bad enough to come after them.

Some of them are customer owned some of them are owned by their respective companies. Usually labelled accordingly. A lot of companies won't fill another company's tank.

[lightman]

Lightman i thing the head thickness on those tanks are about .230’’ thick a little thinner than the shell thickness, would indeed make for a large melting pot. You would need a lot of burner under it, and a good support to hold it up tho.

I doubt that I will do anything. Anyway you look at it I'm closer to the end of my casting career than I am to the beginning of it. But then again, if any of them had propane in them it might be nice to have a larger tank around the shop.

A buddy has a Crawfish pot made from the end of a 500 gallon tank. It uses a huge star burner from a carwash water heater. Its a heck of a set up!

[dg31872]

Just as a base line to gauge how much the propane guy is profiting, we got a 8,000 gallon load of propane last night for 65 cents per gallon. That is delivered to my tank.

[Markopolo]

yikes!!!!! .65 a gallon???? propane here is nearly 4 bucks a gallon!!!! must be an alaskan thing...

[Froogal]

Around here, the propane companies will NOT fill any tank unless they have inspected it, and approved it themselves. One company will NOT fill any tank that they do not own.

[Hossfly]

I was looking for a 20# propane bottle for a member, Tazlaw, and rode down to the river where all of the flooding was last spring. I didn't find Tazlaw a bottle but there are several 250 and 500 size tanks laying in the woods, having broken loose from their attachments and floated away. My buddy, that owns a lot of that property has offered them to me. I was thinking about cutting the end out of one of the 250's and making a smelting pot.

I thought the propane companies owned them but apparently they don't want them bad enough to come after them.

I’ve seen some around here that were old, they almost were giving away for scrap. Thing is if they have a readable serial # they’re good to fill with an inspection of $50, I’ve got an old 150 tank dated 1962 and they fill with no problem. DOT small cyl need testing at 5 years. The Freon 30-50# cyl also make good melting pots, if you got a friend in A/C business they get lots to get rid of and wont blow up with sparks, just be upwind when you cut them.

[lightman]

I have a nice smelting pot. Its just that seeing those tanks laying around got the building part of me stirred up! The pot that I have used for years was the valve cover from a high pressure rail road tank car. Kind of like the valve cover on a bulk propane tank except that its 3/8 inch thick. It will hold close to 400 pounds.

A lot of guys build smokers from those bulk tanks.

[EDG]

Well you never can tell.
Myth busters pulled a vacuum on a railroad tank car and it held up.
Then they dropped something on it with a crane and the tank imploded.


https://youtu.be/Zz95_VvTxZM



So my question is, would the tank stand to be evacuated to deep vacuum, would it implode or collapse with a deep vacuum like that.

Absolutely would not implode or collapse. It was meant to take pressure so if it will take pressure it will also take vacuum.