How to use hydrochloric acid to descale stainless steel heat exchangers?
Thread Content
It is said that hydrochloric acid can be used to descale stainless steel heat exchangers, but the concentration must be carefully controlled. Who has operated it? Could you give an introduction?
It should be possible; keep the hydrochloric acid concentration as low as possible – it’s sufficient to remove scale. After cleaning, rinse thoroughly with clean water. Although I didn’t use hydrochloric acid for degreasing, in the past it was difficult to remove the black scale from 316L steel using traditional pickling solutions; by adding a small amount of hydrochloric acid, the pickling effect was excellent. However, the pickling time, temperature, and the cleaning steps after pickling had to be carefully controlled.
The hydrochloric acid concentration is around 25, the treatment time is 10 minutes, after which it must be rinsed thoroughly with plenty of water. No, try again.
I think this needs to be strictly controlled; although I haven’t carried out any actual operations, chloride ions in hydrochloric acid have a quite strong corrosive effect on stainless steel. When conducting hydrostatic tests, the concentration of chloride ions in the water must be controlled; this is even more true during pickling. After pickling, the area should be cleaned promptly. I think controlling the concentration of hydrochloric acid and how to clean it up after pickling are the key points.
We have used it, but we didn’t measure the concentration; it was based on experience – roughly more than 1 cubic meter of water with 1 bucket (over 20 liters) of hydrochloric acid. Keep washing in a cycle until no dirty foam appears. After washing, rinse once with clean water
1. Control the concentration properly. 2. Neutralize after pickling