Abstract:
Objective The aim is to elucidate the corrosion laws of carbon steel corrosion at different temperatures in representative CCUS conditions, providing theoretical support for CCUS corrosion control.
Method Through simulated evaluation tests, corrosion experiments were conducted using a high-temperature and high-pressure reactor, with the corrosion rate calculated by the weight loss method. The corrosion morphology and product composition were analyzed using analytical techniques such as scanning electron microscopy, X-ray diffraction, and 3D depth-of-field microscopy.
Result When the CO2 partial pressure was 4.0 MPa and the H2S partial pressure was 0.1 MPa, the uniform corrosion rate of N80 steel displayed a non-monotonic trend with increasing temperature, characterized by an initial increase followed by a decrease, with a peak rate observed at approximately 100 ℃, with varying degrees of localized corrosion observed on the specimen surfaces. At this peak temperature, the corrosion product film exhibited the most substantial defects. The corrosion products were identified to be primarily composed of FeCO3 and FeS.
Conclusion The influence of temperature on corrosion reactions in CCUS systems is complex. Under the experimental conditions, with the CO2/H2S partial pressure ratio within a range of 20 to 500, the corrosion process is synergistically controlled by both CO2 and H2S.
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