Sorption Pumping of Hydrogen by Cryodeposits-Sorption Capacity Measurement

摘要

The state-of-the-art of cryosorption of hydrogen (H2) and helium by cold cryodeposited frost is reviewed and summarized in some detail, and the results of additional measurements of the sorption of H2 by carbon dioxide (CO2) frosts are reported. It is shown that the sorption capacity of the frost depends upon the conditions at which the frost was formed and upon its temperature hisory. Frosts formed in a manner to make them porous or disordered are shown to possess greater sorption capacities. It appears that surface diffusion of adsorbed molecules into a disordered frost structure is the basic pumping mechanism. Isotherms for H2 sorbed by CO2 forests formed over a wide range of conditions are presented. Also, the reuse sorption capacity of CO2 frost is well documented. As a result of the present tests, it is now possible to put the process of frost cryosorption pumping into better perspective and understand the conflicting results of previous experimental investigations. (Author)