Analyzing Open Circuit Potential Change versus Time in Corrosion Inhibition Experiments: A Failed Attempt

Abstract Use of organic corrosion inhibitors provides an economical and effective way for internal corrosion control of oil and gas production and transportation pipelines. The motivation to conduct corrosion inhibition measurements using electrochemical techniques was to get an indirect measurement of surface saturation concentration (SSC) for a model corrosion inhibitor compound, tetradecyldimethylbenzylammoniumbromide (BDA-C14), based on the steady state corrosion rate at different bulk inhibitor concentrations measured using a 2L glass cell setup. However, there was another important observation during corrosion inhibition experiments in the present study, which was a sudden rise in open circuit potential (OCP) to more positive values after injection of the corrosion inhibitor. In the present study, this OCP change is analyzed, and a detailed methodology is presented for the estimation of kinetic constants. Following some assumptions, OCP change vs. time data is used instead of the limited number of corrosion rate data points available in the transient region during inhibitor adsorption.