Corrosion Inhibition Performance of Hexahistidine Amide to L245 Steel for Gas Gathering and Transportation Pipeline

Based on the operating conditions of the Nanchuan shale gas gathering and transportation pipeline, the corrosion inhibition performance of hexahistidine amide (16-ZA) inhibitor to L245 carbon steel in simulated formation water was studied. The results of corrosion immerssion test and electrochemical test show that hexahistidine amide corrosion inhibitor had excellent protective performance on L245 carbon steel in saturated CO₂ environment at low concentrations. When the concentiation of the inhibitor was 10 mg/L, the corrosion inhibition rate could reach 90%, and the corrosion inhibition rate increased with the increase of the inhibitor dosage. When the concentration of the inhibitor was 100 mg/L, the corrosion inhibition efficiency was 99%. Hexahistidine amide inhibitor was mainly chemically adsorbed on the surface of carbon steel, and followed the Langmuir isotherm adsorption model. The results of quantum chemistry calculations confirmed that the inhibitor had extremely strong adsorption capacity on the surface of carbon steel.