Operation of a bench-scale TiFe-based alloy tank under mild conditions for low-cost stationary hydrogen storage

Activation processes of 55 kg TiFe-based alloy, filled in a conventional bench-scale tank (TiFe-based tank) under 1.0 MPa Gauge and at 80 °C, and its hydrogen absorption and desorption properties were studied. Following six ab/desorption cycles, the activation process was completed after the seventh absorption process. A long operating time (284 h) was necessary to complete the activation treatment. However, the operating time could be shortened by optimizing each activation process. At a constant hydrogen flow rate of 20 NL/min, the TiFe-based tank absorbed and desorbed >8 Nm3 hydrogen at inlet brine temperatures of 60 °C and 70 °C, respectively. Heat exchange between the alloy bed and the brine circulation during desorption processes was about two times higher than during the absorption processes. Compared with 70 kg LaNi5 filled in the same tank (LaNi5 tank), the heat exchange was higher. This shows the TiFe-based tank would be more suitable for high hydrogen flow operations than the LaNi5 tank.