Sulfuric Acid Tank Anodic Protection

[Sean Rong]

We have a 800-tonne carbon steel tank for storing 93.5% sulfuric acid for sale. Daily acid production is 10-20 tonnes. Each time a truck takes about 27-50 tonnes from the storage tank. Recently anodic protection has been installed for the tank. However, iron concentration in the acid has been hovering around 50-60 ppm while the acid from the process contains less than 10 ppm of iron. Is it possible to get the acid iron concentration below 20 ppm in a carbon steel tank with anodic protection? Thanks very much in advance for your comments! Sean

 

[EdStainless]

What Fe level did you have before?
Has the AP system been in place long enough to turn the contents of the tank over a few times?
My gut feeling is that you should be lower.
But getting to 20ppm may be very difficult.
This is why people often use phenolic lined tanks for H2SO4.

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P.E. Metallurgy, Plymouth Tube

 

[Dhurjati Sen]

@Sean Rong

For H2SO4 tanks, normally corrosion takes place at the bottom and at the top.....

Is your tank bottom plates, shell course upto 1.5 metre from the bottom and the roof underside as well as the top 1.5 metre of the shell course PAINTED?

Even if the tank has been painted internally, when was the last internal inspection of the tank done?

Sometimes, there is no alternative for a shutdown!