Corrosion behaviour of X52 pipeline steel in high H₂S concentration solutions at temperatures ranging from 25°C to 140°C

Abstract

High temperature and high pressure immersion tests in an autoclave were employed to study the corrosion behaviour of X52 pipeline steel in aqueous solutions containing high concentrations of H 2 S. The corrosion products generated were characterised using scanning electron microscope, energy dispersive spectroscopy and X-ray diffraction. It was seen that at a constant H 2 S concentration of 22 g/l, the corrosion rate increased with increasing temperature up to 90uC, thereafter decreased at 120uC and slightly increased again at 140uC while the corrosion rate increased with H 2 S concentration at a temperature of 90uC. When the temperature and H 2 S concentration increased, the corrosion product converted from iron rich to sulphur rich products in the following sequence: mackinawiteRtroiliteRpyrrhotite, where the microstructure and stability of the corrosion products had an important effect on the corrosion rate. The corrosion film was formed through the combination of the outward diffusion of Fe 2z ions and the inward diffusion of H 2 S and HS 2 species.

MoS2/FeS Nanocomposite Catalyst for Efficient Fenton Reaction

“…The dissolved Fe 2+ quickly reacted with H 2 S to form a ferric sulfide precipitant, which exhibited poor catalytic activity (eq ). − To confirm this speculation, we added an AgNO 3 solution to the supernatant of MoS 2 /FeS suspension at pH 3.2 and then studied the UV–vis spectrum (Figure b). Upon mixing, a broad peak assigned to Ag 2 S NPs was observed at 252 nm, and this clearly indicated that H 2 S was released and reacted with Ag + .…”

“…The solution color quickly turned from light-green to black within 2 min (inset of Figure b), which confirmed that a chemical reaction was taking place. Considering that only FeCl 2 ·4H 2 O and H 2 S were present in the solution, it is reasonable to infer ferric sulfide formation. − According to the above investigation, the optimal condition was found to be 5.0 mg of catalyst, 10 mg/L RhB, 20 mM H 2 O 2 , and pH 6.5. The degradation efficiency of various catalysts under the optimal condition was further investigated (Figure ). In the presence of H 2 O 2 but the absence of catalysts, the degradation efficiency was negligible, suggesting that the catalysts were essential for the activation of H 2 O 2 .…”

“…Under the alkaline condition, the activity is usually inferior because of the decreased oxidation potential of • OH and hydroxides precipitation . Additionally, the decomposition of H 2 O 2 into O 2 and H 2 O is accelerated, which affects the utilization efficiency of H 2 O 2 in the Fenton reaction . To this end, it is attractive to explore a catalyst with high activity in the neutral environment because the common problems in the Fenton reaction, such as leaching of metal ions, treatment of iron slurry, and adjusting pH values, can be well solved.…”

“…34 Additionally, the decomposition of H 2 O 2 into O 2 and H 2 O is accelerated, which affects the utilization efficiency of H 2 O 2 in the Fenton reaction. 35 To this end, it is attractive to explore a catalyst with high activity in the neutral environment because the common problems in the Fenton reaction, such as leaching of metal ions, treatment of iron slurry, and adjusting pH values, can be well solved. As shown in Figure S5d, e, the effect of pH values on the Fenton reaction catalyzed by MoS 2 and the physical mixture of MoS 2 +FeS were evaluated.…”

Investigation of pH2S influence on 3% Cr tubing steel corrosion behaviours in CO2–H2S–Cl−environment

“…under this condition. 20 Conclusions 1. In a CO 2 dominated corrosion environment, a trace amount of H 2 S (,40 mbar, pH 2 S/pCO 2 ,1 : 100) will decrease the CO 2 corrosion rate in 3%Cr steel and the steel surface became better as well.…”