Investigation of the Observed Localized Corrosion in an Industrial Steel Cation Exchanger Vessel
Cation exchanger (steel vessel), containing polymeric beads as exchange resin, in a process industry is found to be affected from localized “pitting” corrosion during the turnaround. There are two main cycles of such exchanger’s operation, i.e., normal and regeneration cycles, differentiated by passing canal/well water and sulfuric acid solution, respectively. Corrosion rates by Tafel techniques are measured for both these cycles. The different corrosion rates for canal and well water are explained as per reduction reaction equilibrium. During regeneration cycle, certain other tests like cyclic polarization and potentiostatic polarization are also conducted to understand the cause of the localized corrosion. Potentiostatic tests' observations revealed an interesting phenomenon probably explaining the failure not elucidated by the conventional corrosion measurement techniques.
KeywordsCarbon steel Sulphuric acid Cathodic anodic polarization Potentiostatic measurements Acid corrosion Pitting corrosion
The authors gratefully acknowledge the cooperation provided by Mr. Zaheer Anwar at Fauji Fertilizer Corporation Pakistan, and his taking the initiative in industrial academia collaboration.
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