Measurement of Breakthrough Curves on Pressure Swing Adsorption for Hydrogen Isotope Separation

Abstract

At the National Institute for Fusion Science experimental studies on hydrogen isotope separation by a cryogenic Pressure Swing Adsorption (PSA) process have been carried out in order to apply it to the system of vacuum pumping-gas treatment for the D-D burning experiments of the Large Helical Device. Breakthrough behavior of D₂ in a H₂-D₂ mixture flowing through a synthetic zeolite 5A-type packed-bed column at 77.4 K is examined by using a cryogenic PSA apparatus. The test column used is 40 mm inner diameter. It is filled with spherical adsorbent particles of 2 mm at an amount of 700 g on a dry basis. The hydrogen mixture including D₂ at a concentration of 1 % is used in this experiment. The breakthrough curves obtained by the experiments are accurately simulated by theoretical curves calculated for the system exhibiting the Henry type adsorption. Overall effective mass transfer coefficients are obtained from the comparison of experimental curves with analytical ones. The coefficients increase monotonously with superficial velocity. The sequential operations of PSA, such as adsorption, desorption and pressurization is carried out for several times. It is confirmed that breakthrough curves are reproducible after several repetitions of operation.