Hydrogen liquefaction system

Abstract

A hydrogen liquefaction apparatus according to the present disclosure comprises a compressor located on a hydrogen flow path to perform the first isothermal process; a precooler, a heat exchanger, and a first cryocooler which are connected to the compressor on the hydrogen flow path in this order to perform the first isobaric process; a Joule-Thomson valve connected to the first cryocooler on the hydrogen flow path to perform the isenthalpic process; a storage tank connected to the Joule-Thomson valve on the hydrogen flow path to perform the second isothermal process; and second cryocoolers which are connected to the storage tank on the hydrogen flow path to perform the third isobaric process between the isenthalpic process and the second isothermal process.

What is claimed is: 
     
         1 . A hydrogen liquefaction apparatus for liquefying gaseous hydrogen, which is configured to perform the first isothermal process, the first isobaric process, the isenthalpic process, the second isothermal process, and the second isobaric process in the diagram of temperature T and enthalphy S, comprising:
 a compressor located on a hydrogen flow path to perform the first isothermal process;   a precooler, a heat exchanger, and a first cryocooler which are connected to the compressor on the hydrogen flow path in this order to perform the first isobaric process;   a Joule-Thomson valve connected to the first cryocooler on the hydrogen flow path to perform the isenthalpic process;   a storage tank connected to the Joule-Thomson valve on the hydrogen flow path to perform the second isothermal process; and   second cryocoolers which are connected to the storage tank on the hydrogen flow path to perform the third isobaric process between the isenthalpic process and the second isothermal process,   wherein the third isobaric process connects the isenthalpic process and the second isothermal process therebetween in the diagram of temperature T and enthalphy S.   
     
     
         2 . The hydrogen liquefaction apparatus according to  claim 1 ,
 wherein the compressor mixes and compresses internal gaseous hydrogen and external gaseous hydrogen to produce circulating gaseous hydrogen while maintaining the highest temperature in the diagram when the first isothermal process is performed,   wherein the internal gaseous hydrogen is supplied from the precooler and has absolute temperature of 300K and pressure range of 2 bar to 4 bar, and   wherein the external gaseous hydrogen has absolute temperature of 300K and pressure of 60 bar and is periodically supplied to the compressor from the outside.   
     
     
         3 . The hydrogen liquefaction apparatus according to  claim 2 ,
 wherein the circulating gaseous hydrogen has absolute temperature of 300K and pressure range of 40 bar to 80 bar at the output end of the compressor.   
     
     
         4 . The hydrogen liquefaction apparatus according to  claim 1 ,
 wherein the precooler, the heat exchanger, and the first cryocooler gradually lower the temperature of the circulating gaseous hydrogen from the compressor in this order to produce the 1 st  to the 3 rd  low-temperature gaseous hydrogens when the first isobaric process is performed.   
     
     
         5 . The hydrogen liquefaction apparatus according to  claim 4 ,
 wherein the precooler operates at the initial stage of the first isobaric process to receive the circulating gaseous hydrogen from the compressor and let the circulating gaseous hydrogen and the liquefied natural gas be heat-exchanged to produce the 1 st  low-temperature gaseous hydrogen from the circulating gaseous hydrogen.   
     
     
         6 . The hydrogen liquefaction apparatus according to  claim 5 ,
 wherein the 1 st  low-temperature gaseous hydrogen has absolute temperature range of 77K to 80K and the pressure range of 40 bar to 80 bar at the output end of the precooler.   
     
     
         7 . The hydrogen liquefaction apparatus according to  claim 4 ,
 wherein the heat exchanger operates at the intermediate stage of the first isobaric process to receive the 1 st  low-temperature gaseous hydrogen from the pre-cooler and cools the 1 st  low-temperature gaseous hydrogen to produce the 2 nd  low-temperature gaseous hydrogen.   
     
     
         8 . The hydrogen liquefaction apparatus according to  claim 7 ,
 wherein the 2 nd  low-temperature gaseous hydrogen has absolute temperature range of 60K to 76K and pressure range of 40 bar to 80 bar at the output end of the heat exchanger.   
     
     
         9 . The hydrogen liquefaction apparatus according to  claim 4 ,
 wherein the first cryocooler operates at the final stage of the first isobaric process to receive the 2 nd  low-temperature gaseous hydrogen from the heat exchanger and cools the 2 nd  low-temperature gaseous hydrogen to produce the 3 rd  low-temperature gaseous hydrogen,   wherein the 3 rd  low-temperature gaseous hydrogen is maintained below the maximum inversion temperature at which gaseous state of the 3 rd  low-temperature gaseous hydrogen is converted into liquid state.   
     
     
         10 . The hydrogen liquefaction apparatus according to  claim 9 ,
 wherein the 3 rd  low-temperature gaseous hydrogen has absolute temperature range of 40K to 50K and pressure range of 40 bar to 80 bar at the output end of the first cryocooler.   
     
     
         11 . The hydrogen liquefaction apparatus according to  claim 1 ,
 wherein the Joule-Thomson valve, when performing the isenthalpic process, receives the 3 rd  low-temperature gaseous hydrogen from the first cryocooler, expands the volume of the 3 rd  low-temperature gaseous hydrogen to produce gaseous hydrogen for storing and liquid hydrogen for storing, and supplies the gaseous hydrogen for storing and the liquid hydrogen for storing to the storage tank.   
     
     
         12 . The hydrogen liquefaction apparatus according to  claim 11 ,
 wherein the gaseous hydrogen for storing and the liquid hydrogen for storing have absolute temperature range of 20K to 30K and pressure range of 2 bar to 4 bar at the output end of the Joule-Thomson valve.   
     
     
         13 . The hydrogen liquefaction apparatus according to  claim 1 ,
 wherein the second cryocoolers, when performing the third isobaric process, receive the gaseous hydrogen for storing from the storage tank, cool the gaseous hydrogen for storing to produce the 1 st  low-temperature gaseous hydrogen for storing, and supplies the 1 st  low-temperature gaseous hydrogen for storing to the storage tank.   
     
     
         14 . The hydrogen liquefaction apparatus according to  claim 13 ,
 wherein the 1 st  low-temperature gaseous hydrogen for storing has absolute temperature range of 10K to 20K and pressure range of 2 bar to 4 bar at the output terminals of the second cryocoolers to keep the temperature of the internal atmosphere inside the storage tank constant and is partially liquefied with a portion of the gaseous hydrogen for storing in the storage tank.   
     
     
         15 . The hydrogen liquefaction apparatus according to  claim 1 ,
 wherein the second isothermal process is performed such that the storage tank receives and stores the gaseous hydrogen for storing and the liquid hydrogen for storing from the Joule-Thomson valve, that the gaseous hydrogen for storing contacts with the 1 st  low-temperature gaseous hydrogen for storing from the second cryocoolers inside the storage tank to produce a 2nd low-temperature gaseous hydrogen for storing on the hydrogen flow path, and that the 1 st  low-temperature gaseous hydrogen for storing and the 2 nd  low-temperature gaseous hydrogen for storing are mixed up to produce low-temperature gaseous hydrogen for storing at the lowest temperature on the diagram during the flow of the low-temperature gaseous hydrogen for storing from the inside the storage tank toward the outside the storage tank.   
     
     
         16 . The hydrogen liquefaction apparatus according to  claim 1 ,
 wherein the second isobaric process is performed such that, when viewed along the hydrogen flow path, the temperature of the low-temperature gaseous hydrogen for storing from the storage tank is gradually increased by heating the low-temperature gaseous hydrogen for storing with the heat exchanger and the precooler in this order to produce gaseous hydrogen for raising the temperature and the internal gaseous hydrogen.   
     
     
         17 . The hydrogen liquefaction apparatus according to  claim 16 ,
 wherein the gaseous hydrogen for raising the temperature is formed by heating the low-temperature gaseous hydrogen for storing with the heat exchanger and has absolute temperature range of 140K to 150K and the pressure range of 2 bar to 4 bar at the output end of the heat exchanger.   
     
     
         18 . The hydrogen liquefaction apparatus according to  claim 16 ,
 wherein the internal gaseous hydrogen is formed by heating the gaseous hydrogen for raising the temperature with the liquefied natural gas at the precooler and has absolute temperature of 300K and pressure range of 2 bar to 4 bar at the output end of the precooler.