When selecting nickel-phosphorus electroless plating for the tube bundles in petrochemical heat exchangers, great caution must be exercised
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Below the image is an illustration of the corrosion that occurred after 2 years of use of nickel-phosphorus plating on the tube bundle of the overhead water cooler in a company’s atmospheric and vacuum distillation tower. The system is primarily subject to H2S-HCl-H2O corrosion. The reason for failure is that the coating thickness is less than 60 microns; inspections using the blue dot test revealed a high porosity. Reaching a thickness of over 60 microns results in high costs, affecting the overall expense. Therefore, caution should be exercised when choosing this technology, or other corrosion prevention techniques should be employed.
This post was last edited by kokofan on 2024-5-7 09:46. Does it look okay?
There are always dead corners in the tube bundle’s stress concentration areas; no matter how thick it is, it doesn’t help