Condensation corrosion of carbon steel at low to moderate surface temperature and iron carbonate precipitation kinetics

• Droplet retention time (DRT) is measured for the first time.
• TLC rate is independent of WCR at low surface temperature of about 15 °C.
• FeCO3 precipitation kinetic at the TOL differs from that at the BOL.
• A new FeCO3 precipitation kinetic was proposed for TOL condition.

This study investigates the influence of surface temperature and droplet retention time (DRT) on the corrosion rate, FeCO3 supersaturation, and scaling tendency of carbon steel exposed to water condensation. This corrosion phenomenon is also known as top of the line corrosion (TLC). TLC is found to be governed by surface temperature irrespective of water condensation rates (WCR) at low surface temperature (15 °C). The results also demonstrate that the DRT directly influences FeCO3 supersaturation and scale formation. A new kinetic constant for the calculation of FeCO3 precipitation rate under condensing condition at the top of the line is proposed.