Corrosion inhibition of steel in crude oil storage tanks

Abstract

The corrosion behavior of steel in water from certain oil fields with various organic inhibitors was studied by applying potentiodynamic technique at pH 5.9. The inhibitors which were used include 2-methylbenzimidazole (I), 2-mercaptobenzimidazole (II), 2mercapto-5-methylbenzimidazole (III), and 2-mercaptothiazole (IV). The inhibiting efficiency of the different additives was evaluated from their anodic and cathodic polarization curves at different temperatures.A comparative study of curve fitting procedures using the kinetic thermodynamic model and those utilizing well-known adsorption isotherms was undertaken. Three types of isotherms were used, Langmuir, Frumkin and Flory-Huggins isotherm. The results show that the kinetic-thermodynamic model and Flory-Huggins isotherms are more suitable to fit the data for the four inhibitors, at all applied temperatures. From the values of binding constants, K, the order of inhibitor efficiency is:III > IV > II > I and thus 2-mercapto-5-methylbenzimidazole was the most effective inhibitor. The thermodynamic parameters obtained for all the compounds used showed low values of H ads , which indicates that the action of these inhibitors is physically adsorptive in nature.Mit Hilfe potentiodynamischer Messungen bei pH 5,9 wurde das Korrosionsverhalten von Stahl in Wasser aus bestimmen Ö lfeldern bei Zugabe verschiedener organischer Inhibitoren untersucht. Die eingesetzten Inhibitoren beinhalten 2-Methylbenzimidazole (I), 2-Mercaptobenzimidazole (II), 2-Mercapto-5-Methylbenzimidazole (III), and 2-Mercaptothiazole (IV). Die Inhibitorwirksamkeit der verschiedenen Zusätze wurde aus deren anodischen und kathodischen Polarisationskurven bei verschiedenen Temperaturen ermittelt.Eine vergleichende Untersuchung der Kurvenanpassungen mit Hilfe des kinetisch-thermodynamischen Modells sowie bekannter Adsorptionsisotherme wurde durchgeführt. Dabei wurden drei Arten von Isothermen verwendet, die Langmuir-, die Frumkin-und die Flory-Huggins-Isotherme. Die Ergebnisse zeigen, dass das kinetisch-thermodynamische Modell und die Flory-Huggings-Isotherme bei allen untersuchten Temperaturen besser geeignet sind, die Daten für die vier Inhibitoren anzupassen.Aus den Werten der Bindungskonstanten K ergibt sich die Reihenfolge der Inhibitorwirksamkeit:III > IV > II > I Das bedeutet, dass 2-Mercapto-5-Methylbenzimidazol der wirksamste Inhibitor war. Die für alle eingesetzten Inhibitoren ermittelten thermodynamischen Parameter zeigten niedrige Werte für H ads , was darauf schließen lässt, dass die Wirkung dieser Inhibitoren physikalisch-adsorptiver Natur ist.

Reduction of Cr(VI) in presence of some amino compounds

“…In our present study, a forced convection mechanism is obtained, which agree very well with the relationship (10) given by Eisenberg et al [27] for mass transfer to a rotating cylinder in a turbulent flow system; i.e., the equation represents mass transfer by a convective diffusion mechanism without interference from electrical migration [28][29][30], (20) Sh = 0.079(Sc 0.326 )Re 0.7 .…”

Petroleum Products Transporting Pipeline Corrosion—A Review

“…The main factors, such as surfactant concentration, functional group, hydrophobic chain length, and environment, affecting corrosion inhibition, were discussed as well. Khalifa et al (2003) studied the corrosion inhibition of steel in crude oil storage tanks. Ramachandran et al (1997Ramachandran et al ( , 1999 also studied oleic imidazoline class molecules extensively for corrosion inhibitor oilfield applications, and they described the model for understanding how imidazoline works.…”

Inhibitive Assesment of Stearamide as a Corrosion Inhibitor for Mild Steel in HCl Solution

“…Utilizing inhibitors is one of the costeffective protection methods of metals and alloys in acids such as hydrochloric acid [1][2][3][4][5]. Inhibitors are, in general, organic compounds which have nitrogen, oxygen and sulfur in their molecular structure [1][2][3][4][5][6][7][8][9][10][11][12]. The inhibiting effect is generally explained by the formation of a physical and/or chemical adsorption film barrier on the metal surface [7,13].…”