Know the reasons for a variety of corrosion of the heat exchanger, a reasonable choice of anti-corrosion measures in order to achieve the purpose of efficient use of equipment. In view of the corrosion situation, put forward the following anti-corrosion method: Here mainly introduced corrosion inhibitor, electrochemical protection.
1. corrosion inhibitor
Corrosion inhibitors with chromate as the main ingredient are commonly used in cooling water systems. Chromate ions are an anodic (process) inhibitor that, when combined with a suitable cathodic inhibitor, can be satisfactorily and economically Of the anti-corrosion effect.
Chromate-Zinc-Polyphosphate: The use of polyphosphate is due to its role in cleaning the surface of the metal, corrosion resistance, polyphosphate can be partially converted to orthophosphate, they can also be produced with calcium Of colloidal cations, inhibiting the cathodic process.
Chromate-Zinc-Phosphonate: This method uses sodium phosphonate instead of polyphosphate. Similarly to the previous method, aminomethylene phosphate can also be used for the pH value specified for polyphosphate High occasion. Amino methylene phosphonates can prevent scale, even if the pH value of 9 can control the precipitation of calcium salt.
Chromate-Zinc-Hydrolyzed Polyacrylamide: Due to the dispersion of the polyacrylamide hydrolyzed by the cationic copolymer, it is possible to prevent or inhibit the generation of dirt into scale.
2. Electrochemical protection
Using cathodic protection and anode protection. Cathodic protection is the use of external DC power supply, so that the metal surface into the cathode to achieve protection, this method power consumption, high cost. Anode protection is the protection of the heat exchanger connected to the external power supply anode, so that the metal surface to generate passivation film, which is protected.