Unlocking the impurity-induced pipeline corrosion based on phase behavior of impure CO2 streams

This study explored the phase behavior of impure CO2 streams and further unmasked its effects on pipeline corrosion by combing thermodynamic calculation and corrosion test. Thermodynamically, H2S impurity promotes water precipitation via reducing the H2O solubility in CO2. H2S-induced phase distribution changes point to the root cause of H2S-enhanced corrosion. To mitigate the above effects from impure CO2 streams on pipeline steel, we prepared an amorphous Ni-P coating on steel and found that the formation of protective film endows the coating with good corrosion resistance. Hence, more than 80 % of corrosion effects and the localized corrosion are effectively prevented.