Acid Mixing and Tube Corrosion

[way]

We need to inject sulfuric acid into the cooling water at one of our power plants. The easiest spot for us to do this is in the pipe right before the water goes to our steam condenser. The distance between the injection point and the condenser is only 5 feet. We are going to be injecting acid at the rate of 2 gpm, and the cooling water is flowing at a rate of approximately 47,000 gpm. The acid will be injected through a quill, and it will be used to keep the pond pH around 8.

We are concerned that the acid will not have time to mix adequately, and that some of the water will be at a low enough pH to actually damage the admiralty brass condenser tubes.

What do you all think? Any help is greatly appreciated

 

[TBP]

Countless homeowners destroy swimming pool & spa heaters every year adding chemicals exactly the way you're considering. I've seen all 316L stainless steel HXs fail in a few months. Don't do it. Add the acid downstream of your condenser.

 

[butelja]

I agree with TBP's advice. You should have a static mixing element in the pipeline imediately downstream of an injection quill. Additionally, the materials of construction from the injection point through the static mixer should be compatible with all concentrations of what you are injecting. In this case, for sulfuric acid, that would probably require Alloy 30 Cb3.

 

[Bryex]

If you need a suitable replacement ss for the pipe line, have you thought about 904L this grade was designed specifically for dilute sulphuric acid.

 

[butelja]

My previous post should reference Alloy 20 Cb3, not Alloy 30.