Erythritol for Internal Corrosion Inhibition in Crude Oil Pipelines

Corrosion is identified as a primary factor contributing to a major fraction of crude oil pipeline failures. The internal surfaces of crude oil pipelines experience prolonged exposure to corrosion-causing species with brine as a significant contributing factor to corrosion. To mitigate internal corrosion in steel pipelines, corrosion inhibitors are employed, which are only effective in certain circumstances. Moreover, these corrosion inhibitors are expensive and toxic which can damage the environment. This study explores the use of bio-based erythritol, a four-carbon, four-hydroxyl sugar polyol derived from corn starch, as a potential corrosion inhibitor to mitigate chloride-induced corrosion in pipelines. Erythritol has shown a strong affinity to adsorb itself onto the steel surface and block the active corrosion sites in an aggressive chloride environment. A simulant of crude oil is prepared by taking 25% brine (23% NaCl), 75% corn oil, and 3% soy-lecithin as an emulsifier. To determine the corrosion inhibition efficiency of erythritol, various brine-in-corn-oil emulsions are prepared by incorporating 0%, 1%, 2%, and 3% of erythritol. Accelerated corrosion tests are conducted to visually monitor the corrosion damage on steel specimens, and potentiodynamic polarization tests were used to quantify the corrosion current densities and corrosion rates of steel specimens, subjected to emulsions containing various concentrations of erythritol. The qualitative and quantitative results indicate that erythritol is a promising candidate for corrosion inhibition in crude oil pipelines.