Corrosion Detection of Mild Steel in a Two-Phase Hydrocarbon/Electrolyte System Under Flow Conditions Using Electrochemical Noise Available to Purchase

Electrochemical current noise (ECN) measurements were carried out in hydrocarbon/water mixtures of 3% sodium chloride (NaCl) electrolyte in diesel fuel under stirred conditions (0 to 2,000 rpm), using a rotating ring-ring-disk electrodes (RRRDE) system, which includes three mild steel concentric electrodes embedded in an activated polyester resin (APR). Chemical “activation” of the resin surface allowed electrochemical measurements to be made in the hydrocarbon/ water mixture system. A diesel fuel test solution with a range of chloride electrolyte additions was studied. Three distinctive noise patterns were obtained from an ECN time series: (A) a low noise baseline for diesel in the absence of electrolyte, with very small additions of electrolyte and/or low flow rates; (B) a low noise signal with current transients superimposed obtained from relatively small additions of electrolyte and high rotation rates; and (C) a high amplitude signal for high rotation rates and relatively high additions of electrolyte. For Case B, the number and intensity of current transients is indicative of either proximity to Cases A or C. These results contrast with experiments carried out with a conventional resin (non-activated), which is insensitive to the range of electrolyte additions or stirring conditions. This method can be implemented for water-in-oil mixture systems where early corrosion detection is desirable.