American Nuclear Society
Home

Home / Store / Journals / Electronic Articles / Fusion Science and Technology / Volume 28 / Number 4 / Pages 1738-1748

Mass Transfer Coefficients in Cryosorption of Hydrogen Isotopes on Molecular Sieves or Activated Carbon at 77.4 K

Masabumi Nishikawa, Ken-ichi Tanaka, Mitsuru Uetake

Fusion Science and Technology / Volume 28 / Number 4 / Pages 1738-1748

November 1995

Format:

Price:$30.00
Member Price:$27.00
Member Savings:$3.00

The tritium bred in a deuterium-tritium fusion reactor is removed from its blanket by using helium sweep gas. From the viewpoint of adsorption capacity and pressure of tritium at release, a cryosorption bed, which uses molecular sieves or activated carbon at the temperature of liquid nitrogen, is attractive for the recovery of this tritium. The mass transfer coefficients required to predict the breakthrough curve are experimentally discussed. The overall mass transfer coefficient KFav in the cryosorption of hydrogen isotopes on molecular sieves or activated carbon at 77 K consists of a mass transfer coefficient that represents the transfer from the bulk gas flow to the surface of the adsorbent through the boundary layer kfav, a mass transfer coefficient that represents the axial dispersion in the packed bed kzav and a mass transfer coefficient that represents the intraparticle diffusion through micro pores in the adsorbent particle βksav. The value of βksav is confirmed to be 1 to 50 s−1, which decreases with an increase of hydrogen partial pressure, and the rate-controlling step is βksav when the hydrogen partial pressure is higher than several hundred pascals, and kzav becomes the rate-controlling step when the hydrogen partial pressure is low and gas velocity is slow. The dependence of KFav on hydrogen isotopes and adsorbents appears to be small under the current experimental conditions.

 
 
 
Questions or comments about the site? Contact the ANS Webmaster.
advertisement