Abstract: This invention relates to a continuous process for the preparation of slush hydrogen. The process comprises substantially continuously injecting liquid hydrogen at a temperature slightly above its triple point temperature into a slush hydrogen generator; forming solid hydrogen by removing hydrogen vapor from the slush hydrogen generator; fracturing and dispersing surface solid as it is formed into the slush; concentrating the crystalline solid particles in the slush to a level of at least 30%, and preferably from 45 to 60%, by weight; and substantially continuously removing the slush hydrogen from said slush hydrogen generator at a rate such that a substantially constant level of slush is maintained in said slush hydrogen generator.

Abstract: This invention relates to a continuous process for the preparation of slush hydrogen by the freeze-thaw technique. The process comprises substantially continuously injecting liquid hydrogen at or near its triple point temperature into a slush hydrogen generator; forming solid hydrogen by removing hydrogen vapor from the slush hydrogen generator; alternately adjusting the pressure in the slush hydrogen generator to a pressure below the triple point of hydrogen and then to a pressure slightly above the pressure at the triple point thereby effecting formation and dispersion of solids in said slush; concentrating the crystalline solid particles in the slush to a level of at least 30%, and preferably from 45 to 60%, by weight; and substantially continuously removing the slush hydrogen from said slush hydrogen generator at a rate such that a substantially constant level of slush is maintained in said slush hydrogen generator.

Abstract: The present invention is a process for the liquefaction of hydrogen which utilizes a dense fluid expander and neon as a precoolant refrigerant. In the process, a two phase mixture containing about 85-90% liquid of greater than 95% para-hydrogen is produced in a dense fluid expander. Most of the refrigeration for liquefaction is supplied by a neon refrigeration system, consisting of a centrifugal compressor, heat exchangers and one or more stages of neon expansion. As an option, further refrigeration may be supplied utilizing liquid nitrogen as another precoolant.