Systems and methods for hydrogen liquefaction

Abstract

A hydrogen liquefaction system that utilizes two separate compression services, one controlled via pressure and the other via capacitance, to maintain the rotating equipment at its design point. The system also employs an intermediate flash drum to capture boil off gas and a catalyst bed to convert para-hydrogen into ortho-hydrogen. Changing pressure levels within the turbo expander loop are used to transfer hydrogen from the expander loop into the “condensate” or “feed” streams, while maintaining the “condensate” stream at a constant pressure. The system is capable of efficiently producing high-purity liquid hydrogen at a low cost, making it a valuable tool in industries such as fuel cells, energy storage, and aerospace.

What is claimed is: 
     
         1 . A system for hydrogen gas liquefaction, the system comprising:
 a first compression service connected fluidically to a turbo expander, wherein a first pressure within the turbo expander is controlled to maintain a constant pressure ratio;   a second compression service controlled via capacitive control;   means for actively transferring hydrogen from the expander loop into the feed streams via a condensate loop, thereby changing pressure levels within the turbo expander loop;   an intermediate flash drum for capturing boil off gas at an intermediate pressure; and   wherein the first and second compression services are controlled using separate means but done in unison.   
     
     
         2 . The system according to  claim 1 , wherein the first compression service comprises a reciprocating compressor. 
     
     
         3 . The system according to  claim 2 , wherein the second compression service comprises a reciprocating compressor. 
     
     
         4 . The system according to  claim 3 , wherein the system further comprises one or more turbo expanders that are arranged in a series configuration. 
     
     
         5 . The system according to  claim 4 , wherein the system further comprises a cooling system that cools the compressed hydrogen to a temperature below its boiling point. 
     
     
         6 . The system according to  claim 1 , wherein the system further comprises a control system that regulates the pressure of the compressed hydrogen. 
     
     
         7 . The system according to  claim 6 , wherein the system further comprises a section of catalyst for converting para-hydrogen into ortho-hydrogen. 
     
     
         8 . The system according to  claim 7 , wherein the system further comprises a recycle compressor that compresses the hydrogen that has not been liquefied. 
     
     
         9 . A method for liquefying hydrogen gas, the method comprising:
 providing a first compression service connected to a turbo expander loop, wherein the turbo expander is controlled via pressure;   providing a second compression service controlled via capacitive control;   actively transferring hydrogen from the turbo expander loop into a feed stream, thereby changing pressure levels within the turbo expander loop;   maintaining the condensate stream at a constant pressure while the pressure level of the expander stream is changed;   capturing boil off gas at an intermediate pressure in an intermediate flash drum; and   wherein the first and second compression services are controlled using separate means but done in unison.   
     
     
         10 . The method according to  claim 9 , wherein the capacitive control of the second compression service is achieved through a variable frequency drive. 
     
     
         11 . The method according to  claim 9 , wherein the capacitive control of the second compression service is achieved through variable clearance pockets. 
     
     
         12 . The method according to  claim 9 , wherein the second compression service is achieved through controlled compressor suction valves. 
     
     
         13 . The method according to  claim 9 , wherein the method further comprises a heat exchanger that exchanges heat between the compressed hydrogen and a coolant fluid. 
     
     
         14 . The method according to  claim 9 , wherein the system further comprises a control system that regulates the pressure of the compressed hydrogen. 
     
     
         15 . The method according to  claim 9 , wherein the system further comprises a recycle compressor that compresses the hydrogen that has not been liquefied. 
     
     
         16 . The method according to  claim 9 , wherein the intermediate flash drum operates at a pressure of between about 1 and 3 bar. 
     
     
         17 . An apparatus for liquefying hydrogen comprising:
 a first compression service connected to a turbo expander, wherein the turbo expander is controlled via pressure;   a second compression service controlled via capacitive control; means for actively transferring hydrogen from the expander loop into a feed stream, thereby changing pressure levels within the turbo-expander loop;   an intermediate flash drum for capturing boil off gas at an intermediate pressure;   and a section of catalyst for converting para-hydrogen into ortho-hydrogen; wherein the first and second compression services are controlled using separate means but done in unison; wherein the apparatus is configured to operate within a temperature range of −150° C. to −253° C. and a pressure range of 1 bar to 50 bar.   
     
     
         18 . The apparatus of  claim 17 , wherein the changing pressure levels within the turbo-expander loop are achieved through the use of a pressure regulator. 
     
     
         19 . The apparatus of  claim 17 , wherein the first compression service comprises a reciprocating compressor. 
     
     
         20 . The apparatus of  claim 17 , wherein the second compression service comprises a reciprocating compressor.