Inhibiting Stress Corrosion Cracking of Metal Exposed to Moderate to High Concentrations of Ethanol

摘要

An effective stress corrosion cracking (SCC) inhibiting amount of a corrosion inhibitor is added into a blend of fuel and ethanol that contacts a metal, wherein the corrosion inhibitor is an organic acid selected from citric acid, ascorbic acid, succinic acid, pyruvic acid, maleic acid, oxaloacetic acid, oxalosuccinic acid, ketoglutaric acid, isocitric acid, malic acid, aconitic acid, fumaric acid, isomers of these organic acids, and a combination thereof. For example, the corrosion inhibitors inhibit stress corrosion cracking of pipeline grade metal pipe at ethanol concentrations greater than fifteen percent. In one embodiment, the corrosion inhibitor is added into a blend of fuel and ethanol flowing through a pipeline at a plurality of injection points spaced apart along the length of the pipeline. In one option, the corrosion inhibitor is ammoniated to form the ammonium salt of the organic acid. In another option, the foregoing corrosion inhibitors are used in combination with one or more conventional corrosion inhibitors in an amount that is effective to inhibit general corrosion.