Is acid cleaning and passivation required for the circulating water pipes?

It’s not necessary; of course, you can do it if you’re able to. Is it possible to do it;P

The owner has requested that, in accordance with the \"Design Code for Industrial Circulating Cooling Water Treatment\" (GB/T50050-17), our circulating water system (including equipment and pipelines) undergo chemical cleaning and pre-coating treatment before being put into operation; this type of treatment has not been carried out in any of the projects we have designed previously.

Third-party water treatment companies will do it. What I’m telling you is that water treatment companies generally do not supply concentrated sulfuric acid; one has to find another way to obtain it, as it’s difficult to buy such material – the procedures are complicated, and registration with the police station is also required. Additionally, performing this pre-coating is better than nothing; anyway, when we did it back then, we placed the sheets in the tank and left them there for a long time undergoing pre-coating, and indeed the sheets developed a deep blue colored film layer. But it’s hard to say whether there is a pre-formed structure in the pipe or not. Additionally, in 2007, one of our systems – used by another water treatment company for pre-coating – failed completely due to poor control of the pH level; there was white foam and yellow foam everywhere, as well as leaks. . .

Pickling is necessary; newly installed pipes are covered with rust, oil, and other contaminants, and it’s essential to remove these substances through degreasing and rust removal processes. Rinsing them with water alone is not sufficient for achieving clean results. Passivation serves as a protective measure during transportation, and it is recommended to consider this option. While the effectiveness of passivation is debatable, compared to the risk of pipe corrosion, the cost associated with passivation is not significant；

Chemical cleaning, passivation, and pre-coating are all necessary. It will bring great benefits to the future operation of the circulating water. Our company does this every time a new cooling tower is put into use. .

It would be best if it could be passivated, but isn’t the cost quite high for doing that once?

Closed-loop system, capable of passivation； Open-loop cycle, for pre-coating.