Study On Efficient Corrosion Inhibitor In The Chloromethane Dehydration System At High Temperature

This paper addresses the recent advances on the types and research methods for the carbon steel organic corrosion inhibitor in acid medium and at high temperature, and discusses the mechanism of the organic corrosion inhibitor under acid conditions, several electrochemical test methods, such as quantum chemistry calculation and Laser Raman spectra, were employed to monitor the potential corrosion mechanism.We mainly focus on the study of the efficient corrosion inhibitor at high temperature. The chloromethane dehydration system is severely corroded because of the following corrosive mediums: PH=1.0, Fe2+-1700mg/l,Fe3+-260mg/l,Cl--4945mg/l. A new program of adding an efficient corrosion inhibitor at high temperature is presented to prevent the corrosion of the chloromethane dehydration system .The classical method of weight loss is used to select and rebuild corrosion inhibitors, heterocyclic compounds,quaternary ammonium halides and organic phosphorous compounds were chosen from several inhibitors at last because of the co-operation among them. The rate of inhibitor efficiency is as high as 90%, the effect of corrosion inhibitor is powerful. In this paper, several organic compounds are chosen as inhibitors for 20# carbon steel in hydrochloric acid solution. The protective ability of the inhibitors in corrosive solutions is investigated by potentiodynamic polarization curves (Tafel curves) and electrochemical impedance spectroscope (EIS) methods. The electrochemical kinetics parameters are analyzed with the software of CHI660B electrochemical workstation. The inhibition efficiency is calculated with the corrosion current density and charge transfer resistance. At last, scanning electronic microscope is used to analyze the film of corrosion, an entire,densification absorption film is formed on the surface of carbon steel to prevent the immersion of the corrosive mediums.