Effect of Jet Impingement Velocity and Angle on CO2 Erosion–Corrosion with and without Sand for API 5L-X65 Carbon Steel

• Published in: Materials
• Main Authors: Ihsan Ulhaq Toor, Zakariya Alashwan, Hassan Mohamed Badr, Rached Ben-Mansour, Siamack A. Shirazi
• Format: Text
• Language: English
• Published: Multidisciplinary Digital Publishing Institute 2020
• Subjects: CO 2 erosion–corrosion; flow loop; API 5L X-65; surface roughness; XRD; EDS; SEM; Carbonic acid
• Online Access: https://doi.org/10.3390/ma13092198

Most oil and gas production wells have plenty of corrosive species present along with solid particles. In such production environments, CO2 gas can dissolve in free phase water and form carbonic acid (H2CO3). This carbonic acid, along with fluid flow and with/without solid particles (sand or other entrained particles), can result in unpredictable severe localized CO2 corrosion and/or erosion–corrosion (EC). So, in this work, the CO2 EC performance of API 5L X-65 carbon steel, a commonly used material in many oil and gas piping infrastructure, was investigated. A recirculating flow loop was used to perform these studies at three different CO2 concentrations (pH values of 4.5, 5.0, and 5.5), two impingement velocities (8 and 16 m/s), three impingement angles (15°, 45°, and 90°), and with/without 2000 ppm sand particles for a duration of 3 h in 0.2 M NaCl solution at room temperature. Corrosion products were characterized using FE-SEM, EDS, and XRD. The CO2 EC rates were found to decrease with an increase in the pH value due to the increased availability of H+ ions. The highest CO2 erosion–corrosion rates were observed at a 45° impingement angle in the presence of solid particles under all conditions. It was also observed that a change in pH value influenced the morphology and corrosion resistance of the corrosion scales.