Multi-component behaviors of hydrogen isotopes adsorbed on synthetic zeolites 4A and 5A at 77.4K and 87.3K

Breakthrough curves of non-trace H2–D2 mixture replacement adsorption with SZ-13X packed column at 77.4K

“…In a previous work [11,12], the isotherms for H 2 and D 2 adsorbed on SZ-13X at 77.4 K were established experimentally and analytically, and also, the multi-component adsorption behaviors of hydrogen isotopes in equilibrium could be interpreted in accordance with the ideal adsorbed-solution theory, endorsed in experimental data. When the fractions y * H 2 and y * D 2 of H 2 and D 2 in the gas phase in equilibrium with the adsorbed phase are written as…”

“…In the previous paper [12], it is shown that the separation factor depends on the composition of hydrogen isotopes adsorbed. For example, in the atmospheric equilibrium system of H 2 -D 2 mixtures adsorbed onto SZ-13X at 77.4 K, SF D 2 /H 2 varies from 2.05 at y * D 2 ≈ 0 to 2.0 at y * D 2 ≈ 1.…”

Verification of hydrogen isotope separation by pressure swing adsorption process: Successive volume reduction of isotopic gas mixture using SZ-5A column

“…An ideally limiting enrichment factor EF ID in this adsorption system can be defined with the separation factor SF D 2 /H 2 of D 2 diluted in H 2 adsorbed onto SZ-5A at 77.4 K in equilibrium at the atmospheric pressure. The value of SF D 2 /H 2 was already analyzed to be 2.0 in previous papers [7,10]. Accordingly, EF ID = 2.0 is acceptable for the limiting index of enrichment in the adsorption process.…”

“…The imperfect desorption brings a decrease in EF n resulting from the enrichment in the residual adsorbed-phase which is promoted by the isotopic difference in the mass transfer rates during evacuation. In addition to this effect, the enrichment is affected by the behavior of SF D 2 /H 2 depending on the adsorption intensity which exhibits an increase in SF D 2 /H 2 with decreasing the amount of a mixture adsorbed [7,10].…”

“…Considering application of the PSA method to hydrogen isotope separation processes, we have been studying the multi-component behaviors of hydrogen isotopes adsorbed onto synthetic zeolites 3A, 4A, 5A and 13X (SZ-3A, SZ-4A, SZ-5A and SZ-13X) at cryogenic temperatures [7][8][9][10]. In this work, aiming at isolating a volume of H 2 from a hydrogen mixture containing tracer D 2 , a PSA experimental series was carried out using a SZ-5A packed column at the liquid nitrogen temperature 77.4 K. Experimental results show that reasonably effective values are given to factors characterizing the decontamination degree in an isolated H 2 volume, the volumetric reduction of a gas mixture processed and the enrichment 0920-3796/$ -see front matter © 2011 Elsevier B.V. All rights reserved.…”