An ongoing research project is investigating microbiological methanation in an underground natural gas reservoir. Since H2 is involved in the process, hydrogen embrittlement of steel must inevitably be considered. Therefore, a routine for testing has been developed and a unique autoclave test bench was designed to simulate field conditions. The low-alloyed steels L80, P110 (according to API 5CT) and 42CrMo4 (UNS G41400) as well as the 2205 duplex stainless steel (UNS S31803) were investigated.
Constant load tests (CLTs) and immersion tests with subsequent hydrogen analyses were performed. The specimens were exposed to different partial pressures of H2 under both dry and wet conditions (with brine). Additionally, the influence of CO2 under wet conditions was covered.
Tests were performed at two different temperatures (25 °C and 80 °C) and lasted for 30 days. In general, the examined steel grades show a good resistance to hydrogen embrittlement, but significant differences in hydrogen uptake were measured.