l~11~,~a;lr~jl;~~~~;;,; · separation, proc. aesj spring meeting 2003 (in japanese), part i,...

§ 8. Experimental Analysis of HydrogenAdsorption for Isotope Separation/Purification by Pressure SwingAdsorption

Kotoh, K., Fukada, S. (Kyushu Univ. Eng.)Nishida, T., Ikeda, A., Fukuda, K. (Kinki Univ. Eng.,Kyushu)Asakura, Y., Uda, T., Kawano, T., Sugiyama, T.,Yamada, H., Miyazawa, 1.

In order to perform the LHD deuterium experiments, apractical system of hydrogen isotope separation is necessaryfor the environmental safety treatment of exhaust gases. Weare scheming to apply the pressure swing adsorption (PSA)to the isotope separation, and have clarified the equilibriumcharacteristics of multi-component adsorption of hydrogenisotopes on a candidate adsorbent, synthetic zeolite 5A-type,in the previous year's study.

In the present study, a multi-component gas analyzingsystem is developed to measure breakthrough hydrogenisotopes with an adsorption column, and then fundamentalexperiments are carried out for examining the breakthroughcharacteristics of tracer D2 in a Hr D2 mixture with a zeolite5A-type packed-bed column at a cryogenic temperature of77.4 K. Experimental results are theoretically analyzed.

several repeats of operation between adsorption-desorptionprocesses.

iii) Breakthrough curve analysis

The amount of H2 adsorbed at the atmospheric pressure,obtained from a preparatory breakthrough experiment of H2with an original column filled with helium, almost agreeswith the value estimated from the isotherm for H2 on zeolite5A-type shown in the previous report.

The amount of D2 adsorbed which is calculated from abreakthrough curve is consistent with the value estimatedfrom an isotope separation factor of D2/H2 obtained in theprevious study, based on the ideal adsorbed solution theory.The result shows that a separation factor around 2 for D2/H2is expectable in this experimental adsorption system.

Breakthrough curves in adsorption systems exhibiting theHenry type of isotherm can be described with an equationderived from a theoretical model. Since this experimentalsystem is of an isotope molecular exchange reaction whichexhibits the Henry type adsorption, obtained breakthroughcurves of tracer D2 carried on bulk H2 are crossly simulatedby theoretical curves.

In this experimental study, valuable knowledge and dataare obtained, and fundamental but important factors forconsidering the design and operation of a PSA process forhydrogen isotope separation are clarified from the curvefitting analysis.

References

Fig. 1 Breakthrough curves of D2in a hydrogen mixturewith a zeolite 5A-type packed-bed column

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