Tank Blanketing, for long term storage on big tanks?

[SandBar]

So I finally found a nice steel 600 gallon tank, and have been researching how to keep diesel viable for several years. Polishing every 6 months, check. Anti Gel and anti-bugs, check. Nitrogen blanketing seems great, keep all oxygen away and it cannot oxidize. I have nitrogen tanks here for other tasks, it looks as simple as installing a proper nitrogen blanketing valve with emergency pressure relief. Does anyone have experience doing this?

 

[Zed254]

I used to make wine in my basement. Instead of bottling it I decided to try and store it in 5 gallon stainless steel coke kegs....ONCE. I filled the air gap with N2 and then pushed the wine out of the keg with N2. The wine went bad in a very few short weeks. I could not get ALL of the air out of the air gap in the tank. I am confident that wine is WAY more sensitive to air than diesel fuel. I think an N2 blanket on your fuel will provide a very dry environment as long as you have low pressure on it to keep the space full of N2 as you consume fuel and this is what you want: minimum moisture.

But N2 can kill you quickly. Unlike the following event you will not be able to see or smell the N2 in your system. If it replaces the breathable air in your fuel tank farm it can be deadly. Read up on the safety rules around handling N2......https://www.foxnews.com/us/liquid-nitrogen-leak-georgia-poultry-plant-kills-6

 

[Scoobyshep]

Atmosphere is 70 some odd % n2 already. If i were to do a gas blanket it would be argon.

I store fuel in 6 gallon tanks and i have had really good luck with biocide.

Sent from my SM-G973U using Tapatalk

 

[SandBar]

I found Blanketing Valves for cheap as surplus (5,000 vs 200), they maintain a blanket by sensing pressure drop in the vessel and allowing nitrogen to enter (like a wastegate of sorts). My tank will be outside, so no worries of asphyxiation on this setup. Maybe I am going overboard but my goal is 5 year life, as the volume of fuel if not used for actual outage will be used before that mark through monthly exercising of the generator.

 

[DieselAddict]

If you can do it safely it absolutely will extend the shelf life of the fuel.

We intert tanks and processes all the time as part of my day job. Nitrogen is normally the first choice due to its availability and low cost. Argon tends to be used more in the lab/small scale environment where the higher cost doesn't sting as much.

 

[SandBar]

Safety is a priority, being it is outside and using what as a 5000 dollar blanketing valve, combined with a pressure relief valve (what I read is the correct way to blanket). I will also have the tank as full as possible, however monthly excercising will deplete it somewhat and the nitrogen should fill the void. Think 5 years is feasible?

 

[MrShawn305]

Safety is a priority, being it is outside and using what as a 5000 dollar blanketing valve, combined with a pressure relief valve (what I read is the correct way to blanket). I will also have the tank as full as possible, however monthly excercising will deplete it somewhat and the nitrogen should fill the void. Think 5 years is feasible?

What are you planning on feeding it with? A high pressure nitrogen bottle or a dewer?

 

[DieselAddict]

What are you planning on feeding it with? A high pressure nitrogen bottle or a dewer?

Lets hope its a HP bottle since you have ~1% loss per day for most cryo storage systems.

 

[MrShawn305]

Lets hope its a HP bottle since you have ~1% loss per day for most cryo storage systems.

That's why I was asking lol

 

[Scoobyshep]

I seem to recall argon not being as expensive, maybe my supplier has a discount or something.

 

[DieselAddict]

I would love to find argon cheap. Would be an excuse to do a lot more TIG practice.

Markets vary but here in the NC area argon is about 30% more costly than nitrogen. Could also help that the N2 volume is 2-3 tanker trucks per week versus one truck of argon every few months.

One plus with argon is the losses on cryo storage is a lot less than N2.

 

[SandBar]

HP bottle, locally it is super cheap to refill. Same place I get my welding gas.

 

[Zed254]

Safety is a priority, being it is outside and using what as a 5000 dollar blanketing valve, combined with a pressure relief valve (what I read is the correct way to blanket).

Relief valve is needed to protect your vessel from over pressurization by your N2 bottle.

 

[SandBar]

Yes. As it is, I am tryingt to figure out how much pressure to set it at for a diesel tank. The model blanketing valve I bought surplus defaults to 60psi which seems high to me, but can be turned way down to 4psi.

 

[Zed254]

If your tank is a pressure vessel it has a maximum pressure value stamped on it. You want to be below this pressure. Say it's a 15 psi pressure vessel: if you put 60 psi N2 on it you will split the vessel open. If I were doing it I would be at the minimum value: and I think a 3 psi blanket is better than a 4 psi blanket pressure.

This outfit suggests less than 1 psi: https://www.protectoseal.com/resources/understanding-tank-safety/tank-blanketing/

 

[DieselAddict]

If you don't have a pressure rated tank its best to keep the pressure down to a few PSI. A typical overlay pressure for a tank is under 5 PSI differential. Its low enough we normally measure it in inches of water column instead of PSI.

 

[SandBar]

Ahah, I think I misspoke on this surplus blanketing unit. The specs did mention inches of water also. I will find it and paste some specs in. I do want to do this correctly.

 

[DieselAddict]

Post a photo of the tag if you can. Would be interested to see exactly what you are looking at.

 

[Zed254]

You might want to install a pressure relief valve in your system to protect the vessel in case your blanketing valve fails. Ebay has a 1" Jordon 608 blanketing valve available, but the tag is hard for me to read. Might be a 5-30 inch with a maximum pressure of 1.50psi. Confirm before you buy!!!

Here are some installation considerations:

https://www.jordanvalve.com/wp-content/uploads/2020/03/608lg_api2000_im.pdf

 

[SandBar]

Thats the same model i got here locally, seems solid.