Hydrogen liquefaction system and hydrogen liquefaction method

A hydrogen liquefaction system, comprising:

• a hydrogen pipe, where gaseous hydrogen is introduced at a front end, heat exchange occurs in a heat exchange section leading to liquefaction of gaseous hydrogen into liquid hydrogen, and liquefied liquid hydrogen can be discharged at a rear end;
• a cooling cycle device that is in thermal contact with the heat exchange section of the hydrogen pipe so as to perform heat exchange with the heat exchange section of the hydrogen pipe such that gaseous hydrogen can be liquefied into liquid hydrogen;
• and
• an Ortho-Para (O-P) converter formed in the hydrogen pipe, converting a ratio of ortho-hydrogen to para-hydrogen in a process of liquefying gaseous hydrogen into liquid hydrogen;
• and
• a bypass device formed in the hydrogen pipe such that gaseous hydrogen or liquid hydrogen can optionally bypass the O-P converter,
• wherein the O-P converter is formed in the hydrogen pipe that protrudes to outside from the cooling cycle device, being formed to be surrounded by a heat exchange chamber,
• wherein the heat exchange chamber is a vacuum chamber, which includes:
• a liquid nitrogen supply pipe formed on one side so as to perform heat exchange by using low-temperature liquid nitrogen or latent heat that is generated when liquid nitrogen is vaporized into gaseous nitrogen;
• and a gaseous nitrogen discharge pipe formed on the other side, and
• whereby heat generated from the converting of the ratio of ortho-hydrogen to para-hydrogen is thermally isolated from the cooling cycle device so as to reduce deterioration of liquefaction efficiency.