Fusion Science and Technology / Volume 54 / Number 2 / August 2008 / Pages 411-414
Technical Paper / Isotope Separation
Focusing on synthetic zeolites that adsorb hydrogen isotopes at liquid N2 temperature with priority in the order of T2, DT, D2, HT, HD and H2, we have been developing a pressure swing adsorption process system for hydrogen isotope separation. For this purpose, we carried out fundamental experiments of adsorption and desorption of a tracer D2 in bulk H2 with zeolite packedbed columns. In this paper, the results are reported that D2 is enriched in the adsorbed phase at separation factors near 2.0, flowing through zeolite 5A and 13X packed-beds at 77.4 K. These are in agreement with values predicted from the multi-component equilibrium characteristics. In the gas samples recovered by evacuating the packed-beds, however, D2 was detected at a relative concentration of 1.20 or 1.32 to that in the feed gas. This lower range results from the isotopic mass effect in kinetic process. That suggests a highly D2-enriched residual left during evacuation. This is verified with an unusually high enrichment factor of 6.68 or 9.21 for zeolite 5A or 13X measured in the residual sample desorbed from the packed-bed by heating up to room temperature.