Inhibitors

The addition of corrosion inhibitors (continuous or batch) is by far the most effective method of controlling internal corrosion. Laboratory methodologies to evaluate corrosion inhibitors have been standardized by ASTM: ASTM G170: "Evaluating and Qualifying Oilfield and Refinery Corrosion Inhibitors in the Laboratory." In addition to evaluating inhibitor efficiency, the inhibitors are traditionally evaluated for water/oil partitioning, solubility, emulsification tendency, foam tendency, thermal stability, and compatibility with other additives/materials.

Recent regulatory changes require that additional properties of corrosion inhibitors, including environmental friendliness (green inhibitors), drag reduction properties and wettability tendency, as well as the effect on inversion point, should also be evaluated before their application.