Study of the inhibition of hydrogen sulfide corrosion of steel in synthetic stratum water using the complex method

Issue 24(3) 2019
Pages 14-21

L. E. Tsygankova, Derzhavin State University, Tambov, Russian Federation
N. Alshikha, Derzhavin State University, Tambov, Russian Federation
A. A. Kostyakova, Derzhavin State University, Tambov, Russian Federation


Keywords: corrosion, steel, hydrogen sulfide, inhibitor, protective effect, hydrogen, diffusion, membrane, impedance, polarization resistance

http://www.doi.org/0.31615/j.corros.prot.2019.93.3-2

 

The inhibitory effect of the condensation product of tall acids and polyethylene polyamines with respect to corrosion and hydrogenation of carbon steel in a hydrogen sulfide medium was investigated by methods of potentiodynamic polarization, impedance spectroscopy, polarization resistance and gravimetric measurements. The measurements were carried out in the model NACE stratum water, recommended by the National Association of Corrosion Engineers of the USA, containing 5 g/l NaCl and 0.25 g/l CH3COOH. The medium was saturated with hydrogen sulfide at a concentration of 50…400 mg/l. To measure the instantaneous rate of corrosion of steel, the method of linear polarization resistance was used. This made it possible to calculate the contributions of the film of sulfide corrosion products and the inhibitor to the total protective
effect. The method of electrochemical impedance spectroscopy confirmed the reduction of the corrosion rate over time in both uninhibited and inhibited solutions. In addition, data on the adsorption of the inhibitor on the electrode were obtained. This made it possible to calculate a surface coverage with an inhibitor. The diffusion of hydrogen through a steel membrane and its deceleration in the presence of an inhibitor were investigated using an electrochemical diffusion technique.