Process for liquefying hydrogen

Abstract

The invention relates to a process for liquefying hydrogen. To reduce the specific energy consumption, the following process steps are used: a) the precooling of the hydrogen stream by indirect heat exchange against a pressurized LNG stream to a temperature of between 140 and 130 K, b) the precooling of the hydrogen stream by indirect heat exchange against a coolant to a temperature of between 85 and 75 K, c) where the precooling of the coolant takes place against a pressurized LNG stream, and d) the cooling and at least partial liquefaction of the precooled hydrogen stream takes place by indirect heat exchange against another hydrogen stream channeled through a closed cooling circuit, e) where the precooling of the condensed hydrogen stream, which is channeled through a closed cooling circuit, takes place against a pressurized LNG stream.

1 . A method for liquefying hydrogen, comprising the following method steps:
 a) precooling of the hydrogen stream by indirect heat exchange against a pressurized LNG stream to a temperature of between 140 and 130 K,   b) precooling of the hydrogen stream by indirect heat exchange against a coolant to a temperature of between 85 and 75 K,   c) with the precooling of the coolant taking place against a pressurized LNG stream, and   d) cooling and at least partial liquefaction of the precooled hydrogen stream by indirect heat exchange against a further hydrogen stream which is circulated in a closed cooling circuit,   e) with the precooling of the compressed hydrogen stream, which is circulated in a closed cooling circuit, taking place against a pressurized LNG stream.   
     
     
         2 . The method as claimed in  claim 1 , characterized in that nitrogen is used as coolant for the precooling of the hydrogen stream.