A New Arrangement for the Ortho-Para Conversion of Liquid Hydrogen in the Large CEL-NBS Liquefier

  • V. J. Johnson
Conference paper
Part of the Advances in Cryogenic Engineering book series (ACRE, volume 2)


The tremendous increase in efficiency of the iron hydroxide catalyst described in the preceding paper (A-3) made it extremely attractive for use in the large CEL-NBS hydrogen liquefier s. The 30% chromic oxide gel used for catalyzing the ortho-para conversion of hydrogen in the liquefier s has proven reasonably satisfactory except that to obtain 95% para liquid at full plant capacity 50 liters or more of the catalyst is required. This amount fills a considerable portion of the liquid reservoir and has large heat capacity which appreciably prolongs the time required to cool the liqurfier on start-up. The liter or so of the new catalyst estimated for accomplishing the same degree of conversion would have a negligible heat capacity.


Heat Exchanger Total Flow Rate Liquid Hydrogen Para Hydrogen Para Concentration 
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  1. 1p.
    C. Vander Arend, formerly Chief, Cryogenic Processes Section, Cryogenic Engineering Laboratory; present address, Air Products, Inc., Allentown, Pa.Google Scholar

Copyright information

© Plenum Press, Inc., New York 1960

Authors and Affiliations

  • V. J. Johnson
    • 1
  1. 1.CELNational Bureau of StandardsBoulderUSA

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