Hydrogen Sulfide Corrosion of Carbon and Stainless Steel Alloys in Mixtures of Renewable Fuel Sources under Co-Processing Conditions

Abstract

Corrosion rates of steel alloys were investigated in gas oil and its mixture with waste cooking oil and animal waste lard over 1, 3, 7 and 21 days under desulfurizing condition. Co-processing conditions were attempted to simulate by batch-reactor experiment at temperatures between 200 and 300oC and pressures between 20 and 90 bar in the presence of 2 volume% hydrogen sulfide. Integral and differential corrosion rates were defined by weight losses. Intense sulfide corrosion of carbon steels was less impacted by the biomass sources. Thinner scales in gas oil was probably due to frequent cohesive failure, whereas thicker layers in biomass mixtures were allowed to form to afford limited physical protection. The high corrosion rate of low alloy steel with temperature over time is related to inefficient protection by the metal sulfide scales. Greater activation energy and enthalpy balance in the formation of activated complex is expected to reflect in thick cohesive scales. Loose layers and the less unfavorable entropy balance in the transition state did not lead to valuable barrier protection. High sulfide corrosion resistance of stainless steels is in chemical in nature markedly impacted by the biomass fuel sources and contributed especially by the acidic species. Corrosion rates increased with temperature by magnitude similar to those of carbon steels, which probably owes to the less unfavorable entropy and free energy balance between the initial and transition states of the reactants.

Comparative corrosion behaviour of austenitic 316L and duplex 2205 stainless steels: microstructure and property evolution at highly partial pressure of H2S

“…Both steels show the same dominant peaks of the Ni 2p signal in the spectrum corresponding to Ni(OH) 2 , indicating that Ni(OH) 2 could stably exist in the passive film. In addition, it has been reported that NiS can also persist in an H 2 S–Cl − environment and can deposit on the steel surface and prevent corrosion attackers from accessing the surface [39].

Figure 20 XPS spectra deconvolution of passive films formed on (a) 316L and (b) 2205 stainless steels for a narrow scan of Ni 2p at 15 bar partial pressure H 2 S in NACE solution-A.

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“…Both steels show the same dominant peaks of the Ni 2p signal in the spectrum corresponding to Ni(OH) 2 , indicating that Ni(OH) 2 could stably exist in the passive film. In addition, it has been reported that NiS can also persist in an H 2 S-Cl − environment and can deposit on the steel surface and prevent corrosion attackers from accessing the surface[39].…”