Hydrogen liquefaction device and hydrogen liquefaction method

Abstract

The present disclosure relates to a hydrogen liquefaction device capable of liquefying gaseous hydrogen into a liquid state through multi-stage cooling by heat exchange between a heat pipe in which a refrigerant cooled by a cryocooler flows and hydrogen flowing through a micro-channel. The device may comprise a hydrogen pipe for connecting a hydrogen supply unit in which gaseous hydrogen is stored and a storage container in which liquid hydrogen liquefied in a liquid state is stored; and a heat exchange unit that cools hydrogen by at least one or more heat exchangers installed on the hydrogen pipe so that hydrogen being introduced from the hydrogen supply unit and flowing through the hydrogen pipe toward the storage container can be cooled and liquefied in a process of passing through the hydrogen pipe and be discharged to the storage container as liquid hydrogen.

What is claimed is: 
     
         1 . A hydrogen liquefaction device, comprising:
 a hydrogen pipe for connecting a hydrogen supply unit in which gaseous hydrogen is stored and a storage container in which liquid hydrogen liquefied in a liquid state is stored; and   a heat exchange unit that cools hydrogen by at least one or more heat exchangers installed on the hydrogen pipe so that hydrogen being introduced from the hydrogen supply unit and flowing through the hydrogen pipe toward the storage container can be cooled and liquefied in a process of passing through the hydrogen pipe and be discharged to the storage container as liquid hydrogen;   
       wherein the heat exchanger includes:
 a cryocooler; 
 a heat transfer unit configured to be in thermal contact with the cryocooler; and 
 a heat exchange unit configured to be in thermal contact with the heat transfer unit and including a micro-channel formed therein through which hydrogen can flow to perform heat exchange between the cryocooler and hydrogen through the heat transfer unit. 
 
     
     
         2 . The hydrogen liquefaction device according to  claim 1 ,
 wherein the heat transfer unit is formed in a pipe shape elongated in a vertical direction so that one end thereof can be in thermal contact with the cryocooler, and includes a heat pipe filled with a refrigerant therein;   wherein the heat exchange unit is formed to surround the heat pipe, which is formed in a pipe shape, in an annular shape, and is formed with a micro-channel such that the heat exchange between the cryocooler and hydrogen can be performed by heat convection of the refrigerant.   
     
     
         3 . The hydrogen liquefaction device according to  claim 2 ,
 wherein a top portion in the pipe shape of the heat pipe is configured to be in contact with a cold head of the cryocooler such that the refrigerant vaporized into a gaseous state at a bottom in the pipe shape and raised to the top portion is liquefied again into a liquid state to flow back down along an inner wall by gravity.   
     
     
         4 . The hydrogen liquefaction device according to  claim 2 ,
 wherein the heat exchanger further includes:   
       a refrigerant supply unit capable of supplying or retrieving at least any one of methane, argon, nitrogen, neon, hydrogen, and helium into the heat pipe as the refrigerant. 
     
     
         5 . The hydrogen liquefaction device according to  claim 4 ,
 wherein the refrigerant supply unit is configured to fill a single refrigerant made of any one of methane, argon, nitrogen, neon, hydrogen, and helium, or a mixed refrigerant made of mixed materials including at least two materials of methane, argon, nitrogen, neon, hydrogen, and helium at a predetermined ratio and pressure so as to fill the heat pipe with the refrigerant suitable for a predetermined temperature range in which heat exchange is performed in the heat exchanger.   
     
     
         6 . The hydrogen liquefaction device according to  claim 2 ,
 wherein the heat pipe is configured to be filled with a single refrigerant made of any one of methane, argon, nitrogen, neon, hydrogen, and helium, or a mixed refrigerant made of mixed materials including at least two materials of methane, argon, nitrogen, neon, hydrogen, and helium therein at a predetermined ratio and pressure and to be sealed from outside so as to be suitable for a predetermined temperature range in which heat exchange is performed in the heat exchanger.   
     
     
         7 . The hydrogen liquefaction device according to  claim 2 ,
 wherein the heat exchange unit configured to be filled with a porous material therein or to be installed with at least one of a perforated thin plate and a protruding disk so as to form the micro-channel.   
     
     
         8 . The hydrogen liquefaction device according to  claim 1 ,
 wherein the heat transfer unit includes a heat conductor formed in a pillar shape elongated in a vertical direction so that one end thereof can be in thermal contact with the cryocooler, and   the heat exchange unit is formed as the micro-channel, which is formed to penetrate a surface of the heat conductor or an inside of the heat conductor so as to expand a heat transfer area of the heat conductor, such that heat exchange between the cryocooler and hydrogen can be performed by heat conduction of the heat conductor.   
     
     
         9 . The hydrogen liquefaction device according to  claim 1 ,
 wherein the heat exchange unit includes:   a plurality of heat exchangers installed on the hydrogen pipe at predetermined intervals and having lower cooling temperatures from front to rear based on a flow direction of hydrogen so that hydrogen can be cooled in multiple stages from room temperature to liquefaction temperature in a process of passing through the hydrogen pipe.   
     
     
         10 . The hydrogen liquefaction device according to  claim 9 ,
 wherein the heat exchange unit includes:   a first heat exchanger installed on the hydrogen pipe to cool hydrogen to a first cooling temperature; and   a second heat exchanger installed at a rear of the first heat exchanger based on the flow direction of hydrogen on the hydrogen pipe to cool hydrogen to a second cooling temperature lower than the first cooling temperature.   
     
     
         11 . The hydrogen liquefaction device according to  claim 10 ,
 wherein the hydrogen pipe includes:   a connecting pipe configured to connect a bottom of the first heat exchanger and a top portion of the second heat exchanger to flow hydrogen discharged from the first heat exchanger to the second heat exchanger.   
     
     
         12 . The hydrogen liquefaction device according to  claim 11 ,
 wherein the connecting pipe is installed with a Joule-Thomson (JT) valve to decrease temperature of hydrogen by expanding hydrogen that passes through the connecting pipe.   
     
     
         13 . The hydrogen liquefaction device according to  claim 10 ,
 wherein the heat exchange unit further includes:   an n-th heat exchanger installed at a rear of an n−1th heat exchanger based on a flow direction of hydrogen on the hydrogen pipe to cool hydrogen to an n-th cooling temperature lower than an n−1th cooling temperature.   
     
     
         14 . The hydrogen liquefaction device according to  claim 1 ,
 wherein the cryocooler is configured so that a cold head formed to be in thermal contact with the heat transfer unit to cool the heat transfer unit by conductive cooling is installed in a vacuum container.   
     
     
         15 . A hydrogen liquefaction device, comprising:
 a hydrogen pipe for connecting a hydrogen supply unit in which gaseous hydrogen is stored and a storage container in which liquid hydrogen liquefied in a liquid state is stored; and   a heat exchange unit that cools hydrogen by a plurality of heat exchangers installed on the hydrogen pipe at predetermined intervals and having lower cooling temperatures from front to rear based on a flow direction of hydrogen so that hydrogen being introduced from the hydrogen supply unit and flowing through the hydrogen pipe toward the storage container can be cooled and liquefied in multiple stages in a process of passing through the hydrogen pipe and be discharged to the storage container as liquid hydrogen;   wherein the heat exchanger includes:   a cryocooler;   a heat transfer unit configured to be in thermal contact with the cryocooler; and   a heat exchange unit configured to be in thermal contact with the heat transfer unit and including a micro-channel formed therein through which hydrogen can flow to perform heat exchange between the cryocooler and hydrogen through the heat transfer unit;   wherein the heat transfer unit includes one of a heat pipe formed in a pipe shape elongated in a vertical direction so that one end thereof can be in thermal contact with the cryocooler; and   a heat conductor formed in a pillar shape elongated in a vertical direction so that one end thereof can be in thermal contact with the cryocooler,   wherein the heat exchange unit is formed to surround the heat pipe, which is formed in a pipe shape, in an annular shape, and is formed with a micro-channel through which hydrogen can flow such that heat exchange between the cryocooler and hydrogen can be performed by heat convection of the refrigerant, or is formed as the micro-channel, which is formed to penetrate a surface of the heat conductor or an inside of the heat conductor so as to expand a heat transfer area of the heat conductor, such that heat exchange between the cryocooler and hydrogen can be performed by heat conduction of the heat conductor.   
     
     
         16 . A hydrogen liquefaction method, comprising:
 (a) introducing hydrogen into a hydrogen pipe in a gaseous state from a hydrogen supply unit at room temperature in which hydrogen is stored;   (b) cooling and liquefying hydrogen in a process of passing through the hydrogen pipe by at least one or more heat exchangers installed on the hydrogen pipe; and   (c) discharging liquid hydrogen liquefied in a liquid state from the hydrogen pipe and storing it in a storage container;   
       wherein (b) includes:
 (b-1) cooling the heat transfer unit by a cryocooler that is formed to be in thermal contact with the heat transfer unit of the heat exchanger; 
 (b-2) cooling hydrogen by heat exchange between the cryocooler and the heat exchange unit of the heat exchanger, which is configured to be in thermal contact with the heat transfer unit and includes a micro-channel formed therein through which hydrogen flows, via an intermediary of the heat transfer unit. 
 
     
     
         17 . The hydrogen liquefaction method according to  claim 16 ,
 wherein (b) is performed multiple times by a plurality of heat exchangers installed on the hydrogen pipe at predetermined intervals and having lower cooling temperatures from front to rear based on a flow direction of hydrogen so that hydrogen can be cooled in multiple stages from room temperature to liquefaction temperature in a process of passing through the hydrogen pipe.   
     
     
         18 . The hydrogen liquefaction method according to  claim 17 ,
 wherein, in (b),   when hydrogen cooled in any of the heat exchangers flows through a connecting pipe to another heat exchanger for multi-stage cooling, a volume thereof expands and temperature decreases in a process of passing through a JT valve installed in the connecting pipe.   
     
     
         19 . The hydrogen liquefaction method according to  claim 16 ,
 wherein, in (b-1),   a refrigerant filled inside a heat pipe formed in a pipe shape of the heat transfer unit is liquefied by being cooled by the cryocooler that is in thermal contact with the heat pipe, and   in (b-2),   hydrogen is cooled by heat exchange performed between the cryocooler and hydrogen that flows through the micro-channel inside the heat exchange unit which is formed to surround the heat pipe in an annular shape, by heat convection of the refrigerant vaporized inside the heat pipe.   
     
     
         20 . The hydrogen liquefaction method according to  claim 16 ,
 wherein, in (b-1),   the heat conductor formed in a pillar shape of the heat transfer unit is cooled by the cryocooler which is in thermal contact with the heat conductor, and   in (b-2),   hydrogen is cooled by heat exchange performed between the cryocooler and hydrogen that flows through the micro-channel of the heat exchange unit which is formed to penetrate a surface of the heat conductor or an inside of the heat conductor, by heat conduction of the heat conductor.