Process and installation for the cryogenic purification of hydrogen

摘要

A process and installation for the cryogenic purification of impure hydrogen, of the type in which impure hydrogen is cooled under a low pressure PO to a temperature sufficiently low to condense a predetermined proportion of the impurities, by heat exchange in a thermal heat exchange line (3) with purified hydrogen and with a residual fraction containing the expanded preliminarily condensed impurities (in 11, 12) to a low pressure P1. The remaining cold is supplied by the expansion of purified hydrogen in a turbine (8) with gas bearings and the expanded hydrogen is added to the light impurities expanded at the cold end of the heat exchange line. The turbine (8) is supplied with the gas leaving its bearings (17), after cooling of hydrogen at the labyrinthine seal (18) of the turbine is withdrawn under a pressure slightly less than the interstitial pressure Pi which prevails between the rotor (14) and the stator (16) of this turbine.