System and method for precooling a hydrogen feed stream with concurrent nitrogen liquefaction

Abstract

A system and process for precooling of a hydrogen feed stream with concurrent nitrogen liquefaction is disclosed. The disclosed hydrogen precooling refrigeration system and associated methods employ two centrifugal hydrogen compressors, including a centrifugal hydrogen cold compressor and a centrifugal hydrogen low pressure compressor.

What is claimed is: 
     
         1 . A refrigeration system for precooling of one or more hydrogen feed streams in a hydrogen liquefaction system, the refrigeration system comprising:
 one or more centrifugal compressors to compress at least one of the one or more hydrogen feed streams to a pressure in a range of 40 bar (a) and 70 bar (a);   a first heat exchanger or a set of first heat exchange cores configured to precool the one or more hydrogen feed streams, and cool a high pressure nitrogen refrigerant stream;   a warm turbine/expander configured to receive a first diverted portion of the high pressure nitrogen refrigerant stream and expand the first diverted portion of the high pressure nitrogen refrigerant stream to yield a warm exhaust stream;   a cold turbine/expander configured to receive a second diverted portion of the high pressure nitrogen refrigerant stream and expand the second diverted portion of the high pressure nitrogen refrigerant stream to yield a cold exhaust stream;   an expansion valve disposed in the refrigeration circuit configured for expanding a third portion of the high pressure nitrogen refrigerant stream to yield a two-phase nitrogen stream;   a phase separator disposed in fluid communication with the expansion valve and configured to receive the two-phase nitrogen stream and separate the two-phase nitrogen stream into a nitrogen liquid and a gaseous nitrogen stream;   a second heat exchanger or a set of second heat exchange cores configured to receive the cooled hydrogen feed stream from the first heat exchanger or the set of first heat exchange cores and further precool the one or more hydrogen feed streams to a temperature of about 80 Kelvin or lower via indirect heat exchange with all or a portion of the liquid nitrogen stream received from the phase separator;   wherein the hydrogen feed stream is precooled in the first heat exchanger or a set of first heat exchange cores via indirect heat exchange with the warm exhaust stream, the cold exhaust stream, and the gaseous nitrogen stream from the phase separator;   wherein at least one of the one or more centrifugal compressors is a hydrogen cold compressor configured to compress a hydrogen stream taken from the first heat exchanger or the set of first heat exchange cores.   
     
     
         2 . The refrigeration system of  claim 1 , wherein the hydrogen cold compressor is configured to compress a diverted hydrogen stream taken from the first heat exchanger or the set of first heat exchange cores at a temperature in a range of 150 Kelvin to 185 Kelvin. 
     
     
         3 . The refrigeration system of  claim 1 , wherein the hydrogen cold compressor is configured to compress a diverted hydrogen stream taken from the first heat exchanger or the set of first heat exchange cores at a medium pressure in a range of 2 bar (a) to 9 bar (a). 
     
     
         4 . The refrigeration system of  claim 1 , wherein another of the one or more centrifugal compressors is a low pressure hydrogen compressor configured to compress a low pressure hydrogen stream exiting the first heat exchanger or the set of first heat exchange cores at an ambient temperature to a medium pressure in a range of 2 bar (a) to 9 bar (a) to yield a further compressed hydrogen return stream. 
     
     
         5 . The refrigeration system of  claim 4 , wherein the hydrogen cold compressor is configured to compress a diverted hydrogen stream taken from the first heat exchanger or the set of first heat exchange cores and wherein the diverted hydrogen stream is a mixture of a medium pressure hydrogen return stream warmed in the first heat exchanger or the set of first heat exchange cores and the further compressed hydrogen return stream that is re-cooled in the first heat exchanger or the set of first heat exchange cores. 
     
     
         6 . The refrigeration system of  claim 1 , further comprising:
 a nitrogen feed compressor configured to compress the warmed gaseous nitrogen stream exiting the first heat exchanger or the set of first heat exchange cores;   a nitrogen recycle compressor configured to compress the compressed gaseous nitrogen stream and a nitrogen recycle stream to form a further compressed nitrogen refrigerant stream; and   a warm booster compressor and a cold booster compressor configured to still further compress the further compressed nitrogen refrigerant stream and form the high pressure nitrogen refrigerant stream.   
     
     
         7 . The refrigeration system of  claim 6 , wherein the warm booster compressor and the cold booster compressor are arranged in parallel. 
     
     
         8 . The refrigeration system of  claim 1 , wherein a portion of the liquid nitrogen stream from the phase separator is taken as a liquid nitrogen product stream. 
     
     
         9 . The refrigeration system of  claim 1 , wherein the first diverted stream is less than or equal to about 40% by volume of the high pressure nitrogen refrigerant stream and is expanded in the warm turbine/expander to yield a warm exhaust stream at a temperature of about 170 Kelvin; and wherein the warm exhaust stream is warmed to ambient temperatures in the first heat exchanger or the first set of heat exchanger cores. 
     
     
         10 . The refrigeration system of  claim 9 , wherein the second diverted stream is greater than the volume of the first diverted stream and is expanded in the cold turbine/expander to yield a cold exhaust stream at a temperature of about 97 Kelvin; and wherein the cold exhaust stream is warmed to ambient temperatures in the first heat exchanger or the first set of heat exchanger cores. 
     
     
         11 . The refrigeration system of  claim 10 , wherein an inlet pressure of the cold turbine/expander and an inlet pressure of the warm turbine/expander are equal and an outlet pressure of the cold turbine/expander and an outlet pressure of the warm turbine/expander are equal. 
     
     
         12 . The refrigeration system of  claim 1 , further comprising an ortho/para conversion catalyst configured to treat the precooled hydrogen feed stream exiting the second heat exchanger or the set of second heat exchanger cores. 
     
     
         13 . The refrigeration system of  claim 12 , wherein the second heat exchanger or the set of second heat exchanger cores is further configured to re-cool the treated precooled hydrogen feed stream to a temperature of about 80 Kelvin. 
     
     
         14 . A method of precooling one or more hydrogen feed streams in a hydrogen liquefaction system comprising the steps of:
 (a) compressing at least one of the one or more hydrogen feed streams in one or more centrifugal compressors to a pressure in a range of 40 bar (a) and 70 bar (a);   (b) cooling a high pressure nitrogen refrigerant stream and the one or more hydrogen feed streams in a first heat exchanger or a first set of heat exchanger cores;   (c) diverting a first portion of the high pressure nitrogen refrigerant stream from within the first heat exchanger or the first set of heat exchanger cores to yield a first diverted stream;   (d) expanding the first diverted stream in a warm turbine/expander to yield a warm exhaust stream;   (e) diverting a second portion of the high pressure nitrogen refrigerant stream from within the first heat exchanger or the first set of heat exchanger cores to yield a second diverted stream, wherein the second diverted stream is at a temperature colder than the first diverted stream;   (f) expanding the second diverted stream in a cold turbine/expander to yield a cold exhaust stream;   (g) expanding a third portion of the high pressure nitrogen refrigerant stream in an expansion valve to yield a two-phase nitrogen stream;   (h) separating the two-phase nitrogen stream in a phase separator to yield a liquid nitrogen stream and a gaseous nitrogen stream; and   (i) further precooling the one or more hydrogen feed streams in a second heat exchanger or a set of second heat exchanger cores via indirect heat exchange with all or a portion of the liquid nitrogen stream to yield one or more precooled hydrogen feed streams at a temperature of less than or equal to 80 Kelvin;
 wherein the one or more hydrogen feed streams are precooled in the first heat exchanger or a set of first heat exchange cores via indirect heat exchange with the warm exhaust stream, the cold exhaust stream, and the gaseous nitrogen stream from the phase separator; 
 wherein at least one of the one or more centrifugal compressors is a hydrogen cold compressor configured to compress a hydrogen stream taken from the first heat exchanger or the set of first heat exchange cores. 
   
     
     
         15 . The method of  claim 14 , wherein the hydrogen cold compressor is configured to compress a diverted hydrogen stream taken from the first heat exchanger or the set of first heat exchange cores at a temperature in a range of 150 Kelvin to 185 Kelvin. 
     
     
         16 . The method of  claim 14 , wherein the hydrogen cold compressor is configured to compress a diverted hydrogen stream taken from the first heat exchanger or the set of first heat exchange cores at a medium pressure in a range of 2 bar (a) to 9 bar (a). 
     
     
         17 . The method of  claim 14 , further comprising a low pressure hydrogen compressor configured to compress a low pressure hydrogen stream exiting the first heat exchanger or the set of first heat exchange cores at an ambient temperature to a medium pressure in a range of 2 bar (a) to 9 bar (a) to yield a further compressed hydrogen return stream. 
     
     
         18 . The method of  claim 17 , wherein the hydrogen cold compressor is configured to compress a diverted hydrogen stream taken from the first heat exchanger or the set of first heat exchange cores and wherein the diverted hydrogen stream is a mixture of a medium pressure hydrogen return stream warmed in the first heat exchanger or the set of first heat exchange cores and the further compressed hydrogen return stream that is re-cooled in the first heat exchanger or the set of first heat exchange cores. 
     
     
         19 . The method of  claim 14 , wherein a portion of the liquid nitrogen stream from the phase separator is taken as a liquid nitrogen product stream. 
     
     
         20 . The method of  claim 14 , wherein:
 the first diverted stream is less than or equal to about 40% by volume of the high pressure nitrogen refrigerant stream and the warm exhaust stream is at a temperature of about 170 Kelvin;   the second diverted stream is greater than the volume of the first diverted stream and the cold exhaust stream is at a temperature of about 97 Kelvin; and   wherein the warm exhaust stream and the cold exhaust stream are warmed to ambient temperatures in the first heat exchanger or the first set of heat exchanger cores.