Horizonal 250 gallon propane tank for expansion?

[rkusek]

I've been looking at taking the easy route now. Still having trouble finding someone to weld on old propane tanks. They all want to weld up a type of clamp on bracket. They even have me a little worried putting in the ports on the top and bottom. Someone here suggested just tapping in 3/8" holes straight into the tank ends since the metal is thick enough. I figured standing them at about 60* angle putting about 25 gal of water in tank would make this pretty safe since the drill shouldn't ignite anything with water behind it. I thought I could manhandle the tank into the back of my truck too to take it to the welder to make the clamp on bracket. Even with jacks and blocks I couldn't do it on my own. I could borrow a trailer and get some help but I'm wondering if it wouldn't be much simpler to just leave it horizontal, put it against the wall next to the 2 500 gal storage tanks and use the dip tube for my connection. Someone else mentioned the tank gauge works great to track the water level. I know those dip tubes must go very close to the bottom of the tank and the integrity would have to be sound to function right when used for propane. Does anyone see a downside to using this 250gal tank in this manner? I know it will take up 7 feet of floor space vs. about 3 feet standing up verical. Since I'm not stacking the 2 500gal storage tanks I might just build my storage shelf over all 3 tanks along the same wall. I figured the shelf might make good storage and even give me a place to stack some wood for those really nasty winter days. Is there any reason for not leaving it horizontal other than I am wasting quite a bit of floor space?

 

[DaveBP]

I was debating with myself about the same issues for my system not long ago.

The only argument against a horizontal expansion tank I could come up with is if it is horizontal there is a lot more water surface exposed to oxygen that is can absorb. You may need to add air more frequently. Air's pretty cheap.
Whatever water treatment you use needs to be monitored regularly, anyway. Just more reason to do so.
Easy is very appealing.

If there is any possibility at all there is still propane in that tank then please carefully open one of the ports on the top and fill it completely with water. You could pour a few quarts of hydrogen peroxide in as it fills and let it sit in there for a few days. The peroxide will neutralize a lot (but not all) of the stink. You can then safely get as sparky as you want without water all over you and your tools.

 

[b33p3r]

Propane is heavy and sinks. I would think you'd want the open port on the bottom to release the propane?

 

[woodsmaster]

Propane is heavy and sinks. I would think you'd want the open port on the bottom to release the propane?

Water is heavier than propane and will force it out the top.

 

[rkusek]

All 3 tanks are pretty clean now. Last fall I filled all of them with water, bleach, and lemon joy 3 times flushing them out each time after setting a couple days. 2 of them actually had propane yet (small amount) when I bought them. Unfortunately only one of the 500gal has a bottom port. The 250 gal I'm using for expansion had the most in it and still stinks a little. I think it is just in the pores of the steel like the welders are saying.

Thanks for the input DaveBP. I hadn't thought about the increased area for air penetration and it would be roughly 3 times greater than if the tank was vertical. I thought about dumping a gallon of oil that would presumably float on top of the water and form a barrier between the air and water. It has been talked about here in forum but I don't think anyone has ever done that.

 

[DaveBP]

I thought about dumping a gallon of oil that would presumably float on top of the water and form a barrier between the air and water. It has been talked about here in forum but I don’t think anyone has ever done that.

Our Swedish member, Hansson, has reported that some over there use an oil barrier film in their expansion tanks but he says he and his friends never have. I thought the idea intriguing but if a leak ever drained the expansion tank completely the first place the oil would go is into my circulator and return temperature control valve. Yuk.

I think the safest thing to do is get serious about water treatment ( yes, spending money ) and annual testing to see how big a problem the oxygen incursion really is. If a dose of booster chemical once in a while keeps it under control I could live with that.

I would be more concerned with corrosion at the expansion tank walls where the water wipes up and down with each firing cycle than anywhere else in the system. That would be a carbon steel/water/air environment. Classic red rust. If water treatment can protect the insides of the Garn boilers, which have large areas of exposed wet tank meeting air, it can't be that hard.

I lucked into a 60 gallon 304 stainless tank for scrap price (not to be confused with "cheap") and so I hope to avoid that scenario.

 

[rkusek]

Agree on the water treatment, maybe that is all tha is needed.