How should plate heat exchanger maintain anticorrosion in application?
The reason of the corrosion of the heat exchanger is known, the reasonable choice of anti-corrosion measures can achieve the purpose of efficient utilization of the equipment.In view of the corrosion situation, the following anticorrosion methods are proposed: corrosion inhibitor and electrochemical protection are mainly introduced here.
1. The corrosion inhibitor
Chromate corrosion inhibitors are commonly used in cooling water systems. Chromate ion is an anodic (process) inhibitor.
Chromate - zinc - polyphosphate: polyphosphates are used because of their ability to clean metal surfaces and resist corrosion. Polyphosphates can be partially converted into orthophosphates. They can also form large colloidal cations with calcium, inhibiting the cathode process.
Chromate - zinc - phosphonate: this method USES phosphonate sodium instead of polyphosphate similar to the previous method, aminomethylene-phosphate can also be used for higher than the specified pH for polyphosphate.Aminomethylphosphonates prevent scale and control the precipitation of calcium salts even at a pH of 9.
Chromate - zinc - hydrolyzed polyacrylamide: prevents or inhibits the formation of scale into dirt due to the dispersion of the polyacrylamide hydrolyzed by the cationic copolymer.
2. Electrochemical protection
Adopt cathodic protection and anodic protection.Cathodic protection is the use of external dc power supply, so that the metal surface into the cathode to achieve protection, this method of high power consumption, high cost.Anodic protection is to connect the protected heat exchanger with the anode of external power supply, so that the passivation film can be generated on the metal surface, so as to obtain protection.
The above content is the electrochemical protection method of plate heat exchanger, through understanding the maintenance of plate heat exchanger is very helpful.
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