Optimizing of Corrosion Inhibitor for Coal-Based Ethanol Gasoline and Its Corrosion Inhibition

In view of corrosion problem of coal-based ethanol gasoline to automobile oil system, the optimized formulation of coal-based ethanol gasoline inhibitor Inh-CEG was obtained by orthogonal test. The corrosion inhibition effect of the inhibitor to copper was evaluated referring to the method in 6.1.3 of GB 5096-2017 and flame atomic absorption spectrophotometry. The adsorption mechanism and inhibition mechanism of Inh-CEG were studied by isothermal adsorption model and electrochemical polarization curve. The results show that the inhibition efficiency of Inh-CEG in coal-based ethanol enhanced corrosion medium system and coal-based ethanol gasoline enhanced corrosion medium system was more than 85%, and the copper content in the coal-based ethanol gasoline enhanced corrosion medium system added with Inh-CEG was much lower than that in biomass ethanol gasoline system, which indicated that the inhibitor had a good corrosion inhibition effect. Under the isothermal and isobaric conditions, Inh-CEG molecules could spontaneously adsorb on copper surface to form monolayer adsorption, and the adsorption of Inh-CEG molecules on copper surface conformed to Langmuir adsorption model, which was the result of physical adsorption and chemical adsorption. Inh-CEG was a cathodic corrosion inhibitor in coal-based ethanol gasoline enhanced corrosion medium system.