Experimental investigation on cryogenic hydrogen adsorption of molecular sieves

Tritium extraction system (TES) is one of the most important components in the helium cooled solid breeder test blanket modules (TBMs) of ITER. TES will extract various isotopic species of hydrogen by the liquid nitrogen cooled molecular sieve adsorber beds (MSB). The cryogenic hydrogen adsorption properties of several kinds of molecular sieves have been investigated at the pressure of hydrogen of 100 Pa, 200 Pa, and 0.2 MPa in order to offer the suitable molecular sieve for the MSB in TES. The saturated hydrogen adsorption capacities of the MS5A-2 and MS13X-2 have been measured at 100 Pa hydrogen pressure. To demonstrate the hydrogen extraction from continuous He–H2 purge gases, the MS5A-2 has been tested in circulating 99.79% He–0.21% H2 mixture with a flow rate of 16.8 L/min. The results show that the globular MS5A-2 with a diameter of 3–5 mm can adsorb/desorb hydrogen quickly. The saturated hydrogen adsorption capacity of MS5A-2 is 7.55 ml g−1 (NTP) and MS5A-2 could effectively extract trace hydrogen from mixture gases. As a result, this type of molecular sieve can be the candidate of the one in the MSB in ITER TBM.