Effect of environmental factors on corrosion behaviour of L360QCS pipeline steel in H2S/CO2environments

The present research investigated the effect of H2S/CO2 partial pressure, sulphur deposition and corrosion inhibitor on the corrosion behaviour of L360QCS pipeline steel in H2S/CO2 environments by immersion tests, scanning electron microscope analysis and electrochemical measurements. The results show that the corrosion rate (CR) of L360QCS steel decreased first and then increased with increasing p H2S and p CO2.The CR is closely associated with the protectiveness of corrosion film. Sulphur deposition can cause an acceleration of the corrosion of steel in H2S/CO2 environments. Furthermore, the CR increased obviously with increasing p H2S and p CO2 in sulphur deposition environments. After addition of continuous corrosion inhibitor, the CR decreased significantly in H2S/CO2 environments. Prefilming corrosion inhibitor could enhance the inhibition effect in the presence of continuous corrosion inhibitor.