Abstract
A novel experimental set-up was designed and built to investigate the effect of iron sulfide layer growth on H2S corrosion of carbon steel. Tests were conducted by purging 10% H2S/N2 into 1 wt.% NaCl solution at different temperature (25 0C-80 0C), different pH (pH 4 to pH 6) and different flow conditions (60 rpm and 600 rpm magnetic stirring rates). The exposure period was from 1 day to 7 days. The corrosion behavior was monitored by linear polarization resistance (LPR) and checked with weight loss analysis. The morphology and compositions of surface corrosion products were analyzed by Scanning Electron Microscopy (SEM/EDS), cross section analysis and X-ray Diffraction (XRD) methodology. The results show the balance between iron sulfide precipitation and undermining process, characterized by the scaling tendency, can lead to a variety of corrosion outcomes depending on the environmental parameters such as temperature, pH, and flow rate. Protective corrosion product layer and low corrosion rate were observed at high pH, temperature and low flow rate due to precipitation of a dense corrosion product layer.
