Corrosion Evolution and Mechanisms of N80 Steel in H2S/CO2 Coexisting Systems Under Simulated CCUS-EGR Dynamic Environments

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🔬研究者:Materials scientists and corrosion engineers can use the mechanistic model and experimental data to develop better corrosion-resistant alloys for CCUS environments.

🏢実務担当者:Engineers designing CCUS injection wells can apply the corrosion rate predictions and pitting risk assessments to optimize material choice and monitoring schedules.

This study evaluates the corrosion evolution of N80 steel in H2S/CO2 environments simulating Carbon Capture, Utilization, and Storage-Enhanced Gas Recovery (CCUS-EGR) processes. High-pressure autoclave experiments were conducted to analyze the impacts of CO2/H2S partial pressure ratios (2.9–67.4), temperature (40–80 °C), and flow rate. Grey relational analysis indicates that the CO2/H2S partial pressure ratio dominates uniform corrosion (γ = 0.880), while flow rate and temperature primarily govern pitting behavior (γ > 0.85). Increasing the ratio from 2.9 (H2S-dominated) to 67.4 (CO2-dominated) doubled the uniform corrosion rate to 1.042 mm/y but reduced pitting by 46%. Mechanistically, the semiconductor conductivity of FeS (∼10−1 S/cm) drives deep pitting via “large cathode–small anode” galvanic effects. Additionally, fluid shear stress selectively erodes porous FeCO3, enriching surface FeS and creating differential corrosion patterns. A comprehensive evolution model describing the transition from a H2S-dominated regime to mixed control and finally to a CO2-dominated regime is established, providing a theoretical foundation for wellbore integrity management throughout the CCUS-EGR lifecycle.

• semanticscholar https://doi.org/10.3390/pr14101552first seen 2026-05-15 20:47:34