Corrosion inhibitors used in crude unit applications are characterized by the need for rapid adhesion to the metal surface as well as persistent film formation. Persistent inhibitor films provide increased corrosion inhibition under all conditions, with the greatest benefit occurring during low pH excursions. The use of a dynamic film persistency test based on Linear Polarized Resistance (LPR) measurements allows for the determination of film integrity and relative rates of inhibitor desorption
from the metal surface. The dynamic film persistency test also allows analysis of the consequences of pH excursions on inhibited systems.
Keywords: petroleum refining, corrosion inhibition, crude distillation units, corrosion inhibitors, linear
polarized resistance, inhibitor persistency, pH excursions, desorption.