Treatment of scaling in closed-type cooling towers
Thread Content
The closed-type cooling tower newly installed in the department I manage is used in conjunction with air compressors; after it started operating, it was found that the water heat exchange efficiency had declined. Inspection revealed that scaling on the heat exchanger was severely affecting its heat exchange performance. The tower body is made of galvanized steel plates, while the heat exchanger consists of copper tubes. Now, we need to find solutions and determine how to control water quality. I would like to use salt, acid, and a corrosion inhibitor to remove scale – is there any problem with this approach? I would appreciate advice from those who have experience using this method
The effect of chlorine concentration in water quality on the solubility of copper. In tap water in the Chinese mainland, the chloride ion concentration is generally between 5 and 50 mg/l. In Shanghai, due to the higher amount of chlorine used, the chloride ion concentration is higher, typically ranging from 50 to 60 mg/l (including hypochlorous acid (HClO) formed when chlorine dissolves in water and free chlorine). At such chloride ion concentrations, the solubility of copper in water increases; nevertheless, the concentration of copper ions in water does not exceed 2 mg/l. After a protective film is formed, the dissolution of copper ions decreases, remaining at levels below 1 mg/l. If water contains only copper ions and chloride ions, they naturally combine to form CuCl2
To address the issue of scaling effectively, it is necessary to improve water quality at its root, complemented by scale inhibition mechanisms; contact me on WeChat at dengjun122927