The electroplated galvanized coating on the outer surface of the crossflow cooling tower is achieved through electrolysis using direct or pulsed current, depositing a layer of zinc on the outer surface of the carbon steel pipe. The thickness of the zinc coating is typically 20-30 micrometers. The zinc coating serves as a protective layer at room temperature and offers good protection. The electroplating solution has good dispersion, rapid deposition, stable electrolyte, smooth coating surface, and low cost. The electroplating galvanizing method has been used for surface evaporation air cooler tube bundle heat exchange tube surface corrosion prevention, increasing by about 1.5%. When used in industrial environments like refineries, the lifespan of the equipment is approximately 1-2 years. However, in the past two years, the practical application of equipment with electroplated galvanizing on the outer surface has not been satisfactory. Some equipment experiences external corrosion issues when used for less than 1 year. This is due to the frequent use of high-quality coatings to enhance the corrosion resistance of the zinc coating. The passivation of concentrated or medium-concentration chromate solutions is used to meet environmental protection requirements, reducing the pollution and harm to humans from hexavalent chromium. Adjusting the galvanizing process sometimes results in substandard galvanizing quality. The zinc coating on the outer surface is uneven and not dense, which accelerates the electrochemical corrosion of the heating tubes.

Cooling Tower Pipe Installation Requirements

2. Hot-dip galvanized is a cost-effective surface corrosion prevention process. Initially, the 10# steel heat exchange tube is pickled and rusted, then immersed in molten zinc above 800°C, followed by removing the outer surface which is coated with zinc. To ensure a smooth electroplating on the tube's outer surface, compressed air is jetted externally and then passivated. The external hot-dip galvanizing process results in a zinc layer with strong adhesion, typically around 80μm thick and uniformly distributed, effectively addressing issues of low quality and accelerated electrochemical corrosion of heat exchange tubes. Electroplating zinc. Hot-dip galvanizing is used for the surface evaporation cooling of surface evaporation pipes, increasing equipment cost by 3% and extending the lifespan of the equipment to approximately 3 years.

Shuyu Shunfeng Cooling Tower

3. The new corrosion-resistant iron alloy coating offers up to 3 to 5 times higher corrosion resistance than pure zinc coatings. This is due to the more uniform, finer, and denser grain structure of the ZnFe alloy coating compared to the pure zinc coating, providing enhanced corrosion resistance. It is environmentally friendly and more cost-effective than zinc coating. Wuxi Cooling Tower