Development of High-Temperature Hydrochloric Acid Corrosion Inhibitor and Its Inhibition Behavior

A quinoline quaternary ammonium salt corrosion inhibitor was synthesized using 3-methylquinoline and benzyl chloride as raw materials, and the synthesis conditions were optimized using the orthogonal experimental method. And it was used as the main agent; compounded with enhancers, dispersants, etc. A high-temperature (180 ℃) hydrochloric acid acidification corrosion inhibitor, GWS-G, was developed. Its corrosion inhibition performance was evaluated, and its corrosion inhibition behavior was studied using electrochemical testing, SEM-EDS, XPS analysis, etc. The results show that the corrosion rate of N80 steel after 4 hours of corrosion at 180 ℃ in 20% hydrochloric acid with 5.0% corrosion inhibitor GWS-G was 70.25 g/(m² · h), which met the industry standard requirements. The corrosion inhibitor GWS-G was a mixed-type corrosion inhibitor mainly used to suppress cathodes. It formed a uniform and complete protective film on the surface of N80 steel to suppress corrosion, and the protective ability increased with the increase in inhibitor concentration. XPS analysis results show that the protective film was mainly composed of corrosion inhibitor film, which included corrosion products such as FeOOH, Fe₂O₃, FeCl₂, etc.