Cathodic kinetics of API X70 pipeline steel corrosion in H₂S containing solutions under turbulent flow conditions

Abstract

AbstractAbstractA study has been carried out on the effect of hydrodynamics, temperature and hydrogen sulphide (H2S) concentration on the corrosion of API X70 steel in a flowing 3 wt-% sodium chloride (NaCl) solution. Potentiodynamic polarisation curves were used to characterise the corrosion behaviour of X70 pipeline steel in 3 wt-%NaCl solutions with H2S concentrations 0, 100, 650 and 2550 ppm at two temperatures, 20 and 60°C, and at turbulent flow conditions. To control flow conditions, the rotating cylinder electrode (RCE) in turbulent flow regime (100–5000 rev min&minus1) was used. It was found that the measured cathodic current is influenced by flow and therefore by a diffusion component. By comparing the theoretical and experimental cathodic currents, the H+ reduction reaction is proposed as the main contribution to the total measured cathodic current density.Keywords: H2S CORROSIONPOLARISATION CURVESRCETURBULENT FLOW