Rank: Newbie
Joined: 12/3/2009
Posts: 3
Location: Michigan
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I've been asked to look into replacing our 18000 gallon tanks for 97% sulfuric acid on site. The tanks that we have are approximately 30 years old and we want to downsize to about 6000 gallons. These tanks will be outside in the Michigan elements. I believe what we have right now is plain old carbon steel tanks.
I was hoping that someone could give me some suggestions for replacement tanks. For instance, what type of tank should I use...carbon steel, carbon steel with some sort of liner? How thick should the wall thickness be? Should we look at putting in some type of air drier for the vent?
Any help would be appreciated.
Thanks,
John
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Rank: Member
Joined: 10/15/2008
Posts: 16
Location: Canada
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If your original tank has lasted 30 years, a new tank of similar construction would be acceptable. Reasons for changing might be if you wanted to minimize contamination of the acid by iron or if you have experienced excessive corrosion in some parts of the tank.
A baked phenolic liner is an option but it will require periodic maintenance and repair of the lining.
Anodic protection is probably too expensive for such a small tank.
Stainless steel would be a very expensive upgrade to your current tank but would address any contamination issues you might have.
A vent dryer is a consideration but that depends on the climatic conditions. I don't suppose that Michigan sees a lot of humid days. Do you see any evidence of circumferential corrosion at the liquid level? If the contents of the tank get turned over on a regular basis then a vent dryer is less a requirement.
For the size of tank you are considering, thermoplastic is an option as well.
Are there any freezing concerns storing 97% acid in a Michigan winter?
Regards,
Douglas
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Rank: Newbie
Joined: 12/3/2009
Posts: 3
Location: Michigan
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Thanks for the reply Doug,
We have not seen any freezing conditions in the past.
We use our acid for conditioning a cooling tower, so iron contamination has not been an issue.
As far as circumferential corrosion at the liquid level, we do not know. We had a fitting leak on the top of the tank a few years ago that actually created a hole in the top of the tank and a thining down the outside of the tank. Not exactly sure how long that hole was open to the elements, so we can't be sure how much rain water made it inside. We are looking at having the tank non-destructive tested for thickness, but with the age and size of the tank, I am hoping for just a replacement.
My concern for an air dryer on the system is that in the winter time, we could see some freezing up of the drying agent and not allow air to come in as the level of the tank goes down.
Thanks for your advice. Hopefully this all goes well.
John
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