Hydrogen separation from hydrogen/helium mixtures under different pressures by using U-shaped ZrCo getter beds

Helium is used to clean the torus and extract tritium produced by bleeding blanket in fusion facility. So, large amounts of hydrogen/helium mixtures would be produced during the operation of fusion facility and need to be separated for reuse. Cryogenic absorption bed is always used to realize this purpose along with Pd membrane for deep purification, which is high energy consuming and the procedure is complicated. ZrCo can absorb hydrogen selectively, ensuring its possibility for separating hydrogen from hydrogen/helium mixtures. So, ZrCo getter bed is proposed as a candidate process for the tritium extraction systems of TBM. However, the experimental data about this process is quite limited. In this work, experiments of gas mixtures with different compositions (30 %, 50 % and 80 % He) passing through a U-shaped ZrCo getter bed under different operation pressures (125, 150, 175 and 200 kPa) have been carried out. In general, the gas flux will increase when the operation pressure becomes higher for a given gas mixtures. When the pressure is fixed at a constant value, the flux of the higher hydrogen concentrated gas mixture is larger. Breakthrough always appears when hydrogen absorption volume reaches 30 %∼40 % of maximum equilibrium capacity of ZrCo bed in the static absorption. The obtained results in this paper can provide useful information for the practical design of ZrCo getter bed for H₂/He separation in fusion facility or H₂/inert gas separation in other situation.