The effect of O 2 content on the corrosion behaviour of X65 and 5Cr in water-containing supercritical CO 2 environments

Abstract

14The general and localized corrosion behavior of X65 carbon steel and 5Cr low alloy steel 15were evaluated in a water-saturated supercritical CO 2 environment in the presence of 16 varying concentrations of O 2 . Experiments were performed at a temperature of 35°C and a 17 pressure of 80 bar to simulate the conditions encountered during CO 2 transport and injection. 18Results indicated that increasing O 2 concentration from 0 to 1000 ppm caused a progressive 19 reduction in the general corrosion rate, but served to increase the extent of localized 20 corrosion observed on both materials. Pitting (or localized attack) rates for X65 ranged 21 between 0.9 and 1.7 mm/year, while for 5Cr rose from 0.3 to 1.4 mm/year as O 2 22

Effect of temperature and pressure on corrosion behavior of X65 carbon steel in water-saturated CO 2 transport environments mixed with H 2 S

“…10b. Hua et al (2015b) investigated the corrosion rate of X65 steel in supercritical CO2-H2O system at 35 °C and 8 MPa containing 10 g H2O for 48 hours, and the general corrosion rate was 0.1 mm/year. While in this experiment, the corrosion rate of 0.190 mm/year was recorded for samples exposed to the water-saturated supercritical CO2 at 35 °C and 8 MPa with the presence of 1000 ppmv H2S.…”

“…The recent studies on the supercritical CO2 corrosion mainly focus on impurities such as O2, SO2, mixed CO2 with sulfurous acid or the mixture with H2S (Hua et al, 2015a(Hua et al, , 2015b(Hua et al, , 2017Sun et al, 2016aSun et al, , 2016bSun et al, , 2016cTang et al, 2017;Wei et al, 2016aWei et al, , 2016bXiang et al, 2011Xiang et al, , 2013aXiang et al, , 2013bXiang et al, , 2017b. However, the effect of H2S as impurity on the corrosion behavior of CO2 transmission pipeline has rarely been reported.…”

Corrosion mechanism of low‐alloy steel used for flexible pipe in vapor‐saturated H2S/CO2 and H2S/CO2‐saturated brine conditions

“…In general, there are several undesired impurities in the injected stream such as oxygen (O 2 ), nitrogen mono‐ and dioxide (NO and NO 2 ) and sulphur di‐ and trioxide (SO 2 and SO 3 ). These impurities influence the CO 2 corrosion behavior of low‐alloy steel …”

“…These impurities influence the CO 2 corrosion behavior of low-alloy steel. [25][26][27] In practice, injecting CO 2 stream mixed with these impurities decreases separation cost and simplifies operational process. As mentioned above, H 2 S influences the mechanical properties and corrosion behavior of low-alloy steel in CO 2 brine condition.…”

Comparative study on the corrosion behavior of X52, 3Cr, and 13Cr steel in an O2–H2O–CO2 system: products, reaction kinetics, and pitting sensitivity

“…Elemental Cr induces a transition of the corrosion product from the crystalline to the amorphous state, which results in a denser corrosion scale and decreased susceptibility to localized corrosion [12]. As previously mentioned, the corrosion behavior of steel in a CO 2 environment is affected by H 2 O and O 2 impurities [13] and by the Cr content of the steel [14][15].…”