How hydrogen affects operability of chemical and petrochemical equipment made of carbon and low alloy steel

The report deals with some corrosion problems and corrosion cracking related to the phenomenon of hydrogen accumulation in steel. The authors investigated two kinds of hydrogen-related corrosion cracking that occur in working fluids. In the first case, hydrogen accumulation and hydrogen corrosion of steel were observed at an ammonia plant for 18Cr3MoV steel at high temperatures (up to 420° C) and pressures (up to 32 MPa) in gases containing nitrogen, hydrogen and ammonia. The second case shows hydrogen effect in oil-processing and gas-condensation equipment where fluids contain hydrogen sulfide solution in water. This is observed for 09Mn2Si and 16MnSi steels at temperatures −33° C to +80° C and pressures 0–16 MPa. The investigation results showed that such equipment is working in critical conditions and requires great attention; this is especially relevant to equipment that was in operation for a long period of time. Equipment inspection after a long operation period showed that hydrogen corrosion cracking occurs primarily in welded joints and base metal mainly demonstrates delamination. This problem is mainly caused by the effect of hydrogen and hydrogen-related processes taking place in steel.