Heat exchanger descaling
Thread Content
In the factory, chilled brine is used in the shell side of the heat exchanger. There is a problem now: during maintenance, when the shell side was inspected, it was found to be completely covered with scale made up of brine (resembling thick sludge), which essentially blocked the entire shell side. It was known in advance that saltwater is dirty. But now the problem has arisen: how should this ditch be cleared? Can the alkali solution be circulated? Additionally, there is another phenomenon with saltwater: there are many gray suspended particles in it, and if it is left to stand alone, it takes at least 1 hour or more for the layers to form. If the pH is adjusted to 3-4 using a dilute salt acid, precipitation occurs quickly. What causes this phenomenon?
It’s all scale made of saltwater (like thin mud), which basically blocks the entire shell side. Treatment involves dilute salt and acid cleaning.
Won’t acid cleaning with dilute salts have an impact on the tube bundles?
Is there any good way to get rid of the dirt in saltwater?
The cores have all been removed; we use high-pressure guns (cleaning vehicles) to clean the tubes of our heat exchangers.
Pickling should be carried out, and a professional manufacturer should be consulted for the pickling process; this helps to prevent damage to the equipment while ensuring thorough cleaning； There is a foreign-owned company in Shanghai that specializes in equipment cleaning ； The company’s wastewater treatment equipment has been purchased for the Cepsa project.
The shell side is cut open, right? This will cause damage to the shell side!
Pickling: converts insoluble salts into soluble salts~~
If it’s the tube side of the heat exchanger that is removed, then the shell side consists of thick tubes, which can be easily cleaned using a high-pressure water gun at 9.8 MPa… If the tube side isn’t removed, then dilute acid should be used for cleaning. It’s recommended to hire a specialized company, as they have experience; otherwise, there’s a risk of the tubes getting damaged during cleaning
The high-pressure washer mentioned upstairs is actually a car washing pump; it’s very useful, and we use it to clean the filter plates of pressure filters
It depends on the material. For carbon steel, organic acids require formic acid (ratio: 80% formic acid, 2% corrosion inhibitor, 1% surfactant), while inorganic acids require hydrochloric acid or *AO acid (ratio: 5–10% acid, 1% corrosion inhibitor, 1% stripping agent).