Cl- concentration in circulating water used in stainless steel heat exchangers
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During hydrostatic testing, it is required that the CL- concentration in the testing water not exceed 25 mg/L. However, for stainless steel heat exchangers in accordance with GB50050 standards, it is sufficient that the Cl- concentration in the circulating water be no more than 1000 mg/L. What are the considerations behind setting this limit at such a high level? What is the Cl- level controlled at in your factories’ circulating water systems?
Corrosion inhibitors and scale inhibitors are added to the circulating water in actual operation, but this does not mean that the chloride ion concentration in the circulating water can be maintained at 1000 mg/L for an extended period. Most stainless steels are not resistant to chloride corrosion; reducing the chloride content in circulating water helps ensure the stable and safe operation of circulating water pipelines and heat exchange equipment. Chloride content is a restrictive parameter for circulating water, rather than a recommended one. If the enterprise has the means, it is better to use purified water for recirculated water.