Effect of Salt Concentration on Corrosion Behavior of L360 Mild Steel and Inhibitor Performance in Environment Containing Elemental Sulfur

Corrosion behaviors of L360 mild steel and inhibitor performance of two inhibitors in 3.5% NaCl and 10% NaCl solution in presence of elemental sulfur were investigated in the laboratory to simulate the condition of a sour gas gathering pipeline. The results showed that general corrosion of L360 steel caused by elemental sulfur was independent of salt concentration, but pitting corrosion became severer with the increase of salt concentration. Elemental sulfur significantly accelerated the failure of quaternary ammonium based batch inhibitor. However the inhibition of batch inhibitor was almost not affected by salt concentration. The corrosion of L360 mild steel in presence of elemental sulfur can possibly be controlled to an acceptable level with the right concentration and combination of batch and imidazoline based continuous inhibitor.