Corrosion mechanisms in aqueous solutions containing dissolved H2S. Part 2: Model of the cathodic reactions on a 316L stainless steel rotating disc electrode

Abstract

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 Corrosion mechanisms in aqueous solutions containing dissolved H 2 S. Part 2: Model of the cathodic reactions on a 316L stainless steel rotating disc electrode. AbstractIn H 2 S containing solutions, the reduction of protons with a buffer effect contributing to the transport of protons at the steel surface, is not sufficient to explain the cathodic polarization curves obtained on 316L stainless steel. An additional electrochemical reaction was observed and was attributed to a direct H 2 S reduction. A numerical model is presented with these hypotheses and a good agreement is found with the experimental data presented in a previous paper. With this model it is also possible to present the concentration profiles of the different species involved in the cathodic process.

Mechanism of Cathodic Reactions in Acetic Acid Corrosion of Iron and Mild Steel

“…Considering that the slope of the trendline in this graph is nearly unity (1.02), the increase of the limiting current resulting from the presence of acetic acid was in linear correlation with the concentration of undissociated acetic acid (R 2 = 0.996), regardless of the bulk pH. Furthermore, the intercept of the trendline (3.98) was found to agree well with the theoretically obtained value of 4.01 from Levich equation (Equation [6]) (diffusion coefficient and water kinematic viscosity from Nordsveen, et al 5 ). This agreement indicated that the measured limiting currents are under pure mass transfer control; thus, the surface concentration of undissociated acetic acid was negligibly small.…”

“…Hydrogen sulfide is an example of one such weak acid, where a double wave similar to what is schematically shown in Figure 1(a) was observed. 3,[6][7]41 This double wave was shown to be associated with the mass transfer limiting currents of hydrogen ion reduction and hydrogen sulfide direct reduction. 3 While the presence of the double wave is a strong indication of the weak acid direct reduction, its absence is not conclusive evidence for dismissing this reaction.…”

“…The mechanisms of cathodic reactions in aqueous corroding systems and the presence of weak acids have been the subject of numerous studies. [1][2][3][4][5][6][7][8] Carbonic acid, hydrogen sulfide, and organic acids are the most common weak acids found in oil and gas production, transmission, and processing infrastructure. It is well known that corrosion rate in the presence of these weak acids is significantly higher when compared to strong acids at the same pH.…”

Synergistic corrosion inhibition effect of quinoline quaternary ammonium salt and Gemini surfactant in H2S and CO2 saturated brine solution

“…High-resolution XPS spectra of N 1s of mild steel obtained after immersion in H 2 S and CO 2 saturated brine solution with (a) 50 mg L À1 of 12-3OH-12, (b) 100 mg L À1 of QB, (c) 100 mg L À1 of QB + 10 mg L À1 of 12-3OH-12, (d) 100 mg L À1 of QB + 30 mg L À1 of 12-3OH-12, (e) 100 mg L À1 of QB + 50 mg L À1 of 12-3OH-12 and (f) 100 mg L À1 of QB + 70 mg L À1 of 12-3OH-12 at 60°C. quaternary ammonium ions, ionized from QB and 12-3OH-12 molecules, can be adsorbed on the layer of adsorbed anions through electrostatic interaction [39,56,57]. Subsequently, chemisorption may take place.…”

Investigation of Cathodic Reaction Mechanisms of H2S Corrosion Using a Passive SS304 Rotating Cylinder Electrode

“…The second question is related to the mass transfer rate for the reaction involving direct reduction of H 2 S. In Zheng et al's study 9 on carbon steel corrosion, the measured values of mass transfer limiting current density agreed very well with the calculation of mass transfer rates by Eisenberg correlation using an RCE. However, in Kittel et al 8 and Tribollet et al's research 15 , the measured limiting current density of H 2 S reduction was lower than the calculation by the Levich law. One of their suspicions was related to the use of different materials: carbon steel vs. stainless steel.…”