Electrochemical Investigation of Chloride Pitting Attack on Carbon Steel Piping and its Inhibition by Novel Synthesized Cationic Surfactants

The durability of shell and tube heat exchanger working in rich chloride containing formation water was maximized by providing high immunity towards pitting corrosion. Two new cationic surfactants namely OD20 and OD50 were synthesized from oleic acid derivative to evaluate their performance as pitting corrosion inhibitors for API 5L X 60 type carbon steel alloy. Pitting corrosion technique was executed to evaluate the pitting inhibition performance against pitting attack by studying the anodic cyclic polarization diagram obtained for each synthesized inhibitor. 95.9% inhibition efficiency against pitting growth was reported for OD20 while 89% was measured for OD50. Potentiodynamic polarization measurements and electrochemical impedance spectroscopy were conducted to study the performance of the synthesized inhibitors against uniform type corrosion. High inhibition efficiency against uniform type corrosion was reported for both of the synthesized inhibitors at 92.2% for OD20 and 95.7% for OD50. The obtained electrochemical results were confirmed by investigation of the surface morphology of carbon steel alloy by scanning electron microscope (SEM).