Localized corrosion of stainless steels in oxidizing acid chloride environments can be mitigated by electrochemical protection. With this technique, the stainless steel is polarized in the cathodic direction to a potential in the passive zone. In this paper, electrochemical protection systems for bleached pulp washers, vacuum valves, and power utility flue gas scrubbers are described. For bleach plant conditions, it is shown that electrochemically protected 317L stainless steel has the same corrosion resistance as an unprotected 6%Mo stainless steel. The uses of electrochemical protection systems for monitoring process conditions are also discussed.
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