Hydrogen cooling

Abstract

Hydrogen liquification includes three streams of refrigerant at between −320 to −425 degrees F. A fourth stream has ambient temperature and pressure between 150 to 650 PSIA. Fourth stream cooling flows are cooled by heat exchangers to between −320 to −270 degrees F. A first flow of these cooling flows is reduced across a valve to a two-phase mixture directed to fourth warming flows. A separate fifth stream has ambient temperature and pressure of between 700 and 1200 PSIA. Fifth stream cooling flows have a first flow portion removed by a splitter at between 0 and 60 degrees F., and a second flow portion removed at between −160 and −100 degrees F. The first flow portion and a cooled flow of the second flow portion are feed into expanders that power fifth compressors to reduce a temperature of the fifth stream to serve as the first and second flow portions.

It is claimed: 
     
         1 . A hydrogen gas liquification system comprising:
 a first stream, a second stream and a third stream each including flows of one of fluid or gas at a temperature of between in −320 to −425 degrees Fahrenheit (F);   a fourth stream not mixed with each of the first stream, the second stream and the third stream;   the fourth stream having a first refrigerant having an ambient temperature of between 60 to 150 degrees F. and a pressure of between 150 to 650 pounds per square inch absolute (PSIA);   the fourth stream cooled through fourth cooling flows by one or more heat exchangers to cryogenic temperatures in a range of between −320 to −270 degrees F., wherein a cryogenic liquid first refrigerant flow of the fourth cooling flows is reduced in pressure across a valve such that a temperature of the first refrigerant flow drops due to a Joule-Thomson effect, and a two-phase mixture of the first refrigerant flow is directed to fourth warming flows of the one or more heat exchangers to vaporize the liquid and heat the fluid of the first refrigerant flow to near-ambient conditions of a second refrigerant flow of the fourth warming flows,   the second refrigerant flow of the fourth stream is then compressed and cooled through at least one compressor and cooling stage and returned to the fourth cooling flow;   a fifth stream not mixed with each of the first stream, the second stream, the third stream or the fourth stream;   the fifth stream having a second refrigerant having the ambient temperature of between 60 to 150 degrees F. and a high pressure of between 700 and 1200 PSIA;   the fifth stream cooled through fifth cooling flows by the one or more heat exchangers; a first flow portion of the fifth stream removed by a splitter SP 2  from a first refrigerant flow of the fifth cooling flows at a first temperature of between 0 and 60 degrees F., and a second remainder flow portion of the fifth stream removed by the splitter from the first refrigerant flow of the fifth cooling flows at a second and relatively colder temperature than the first temperature of between −160 and −100 degrees F.; and   the first flow portion and a cooled flow of the second flow portion of the fifth stream each feed into an expander that mechanically powers a fifth compressor to reduce a temperature of the fifth stream to serve as fifth warming flows.   
     
     
         2 . The system of  claim 1 , wherein each expander transfers work energy from fluid of each of the first flow portion and cooled flow into a shaft which powers the fifth compressors. 
     
     
         3 . The system of  claim 1 , further comprising a third flow portion of the fifth stream as a gas or two-phase mixture is brought into the fifth warming flows of the one or more heat exchangers, wherein in the third flow portion of the fifth stream is fully vaporized and warmed and mixed with a fourth flow portion of the fifth stream by a recombiner or mixer such that a mixed stream flow is further warmed by a part of the one or more heat exchangers to the near ambient temperature of between 60 and 150 degrees F.; the mixed stream compressed and cooled through at least one compressor and cooling stage and sent to an input of a fifth compressor. 
     
     
         4 . The system of  claim 1 , wherein during a turndown operation of the system, a mass flow of the fifth stream is reduced by reducing pressure of the second refrigerant by a selected percentage that is based on the percentage or amount of flowrate turndown desired. 
     
     
         5 . The system of  claim 4 , wherein during the turndown operation the system is configured to run at a reduced flowrate at or below 30% of a full load flowrate the system is capable of running at. 
     
     
         6 . The system of  claim 4 , wherein during the turndown operation, pressures of the fifth stream are reduced by releasing coolant, cryogenic fluid or nitrogen of the fifth stream at pressure release valve to lower electrical power needed by a compressor to perform compression of the fifth stream. 
     
     
         7 . The system of  claim 4 , wherein reducing pressures of the second refrigerant includes maintaining a fixed pressure ratio or head change across stages of the fifth stream resulting in a relatively steady volumetric flow and head change through the compression and expansion stages resulting in high efficiency of operation with a reduced electrical load. 
     
     
         8 . The system of  claim 1 , wherein the first refrigerant is nitrogen and the second methane; and wherein none of the liquid, gas or chemical in the fourth stream is combined or mixed with that of the fifth stream. 
     
     
         9 . The system of  claim 1 , wherein the first refrigerant and the second refrigerant are each one of nitrogen, a hydrocarbon, oxygen, hydrogen, helium, or a mixture of these molecules; and wherein each of the first stream, the second stream and the third stream include one of product hydrogen; or refrigerants selected from one of hydrogen, helium, and neon or blends of multiple of those refrigerants. 
     
     
         10 . An efficient pre-cooling Modified Reverse-Brayton Cycle hydrogen cooling system comprising:
 a first chemical stream, a second chemical stream and a third chemical stream each including flows of one of fluid or gas at a temperature of between in −320 to −425 degrees Fahrenheit (F);   a fourth chemical stream having flows that are separate from flows of each of the first chemical stream, the second chemical stream and the third chemical stream;   the fourth chemical stream cooled through fourth cooling flows by one or more heat exchangers to cryogenic temperatures in a range of between −320 to −270 degrees F. wherein a cryogenic liquid first refrigerant flow of the fourth cooling flows is reduced in pressure across a Joule-Thomson (J-T) valve such that a temperature and pressure of the first refrigerant flow drops due to a Joule-Thomson effect;   a two-phase mixture of the first refrigerant flow is directed to fourth warming flows of the one or more heat exchangers to vaporize the liquid and heat the fluid of the first refrigerant flow to near-ambient conditions of a second refrigerant flow of the fourth warming flows,   a fifth chemical stream separate from each of the first chemical stream, the second chemical stream, the third chemical stream and the fourth chemical stream;   the fifth chemical stream having a refrigerant including nitrogen having the ambient temperature of between 60 to 150 degrees F. and a high pressure of between 700 and 1200 psia;   the fifth chemical stream cooled through fifth cooling flows by the one or more heat exchangers; a first flow portion of the fifth chemical stream removed by a splitter from a first refrigerant flow of the fifth cooling flows at a first temperature of between 0 and 60 degrees F.;   a second remainder flow portion of the fifth chemical stream removed by the splitter from the first refrigerant flow of the fifth cooling flows at a second and relatively colder temperature than the first temperature of between −160 and −100 degrees F.;   the first flow portion of the fifth chemical stream feed into a first expander that mechanically uses a first shaft to power a first compressor of the fifth chemical stream to reduce a temperature of the fifth chemical stream to serve as a first flow portion of the fifth warming flow; and a cooled flow of the second flow portion of the fifth chemical stream feeds into a second expander that mechanically uses a second shaft to power a second compressor of the fifth chemical stream to reduce the temperature of the fifth chemical stream to serve as the second flow portion of the fifth warming flow.   
     
     
         11 . The system of  claim 10 , wherein each of the first and second expanders transfer work energy from fluid of each of the first flow portion and cooled flow portion into the first and second shaft which power the first and second compressors, resulting in a reduced temperature of the fifth chemical stream. 
     
     
         12 . The system of  claim 10 , wherein during a turndown operation of the system, a mass flow of the fifth stream is reduced by reducing pressure of the second refrigerant at a pressure release valve by a selected percentage that is based on the percentage or amount of flowrate turndown desired. 
     
     
         13 . The system of  claim 12 , wherein during turndown operation of the system, the system is configured to run at or below 30% of a full load flowrate the system is capable of running at. 
     
     
         14 . The system of  claim 10 , wherein the first refrigerant is not the same refrigerant as the second refrigerant; and wherein none of the liquid, gas or chemical in the fourth stream is combined or mixed with that of the fifth stream. 
     
     
         15 . A method of hydrogen liquification comprising:
 providing a first stream, a second stream and a third stream each including flows of one of fluid or gas at a temperature of between in −320 to −425 degrees Fahrenheit (F);   providing a fourth stream separate from each of the first stream, the second stream and the third stream, the fourth stream having a first refrigerant of primarily nitrogen having an ambient temperature of between 60 to 150 degrees F. and a pressure of between 150 to 650 psia (pounds per square inch absolute);   cooling the fourth stream through fourth cooling flows by one or more heat exchangers to cryogenic temperatures in a range of between −320 to −270 degrees F.;   reducing pressure of a cryogenic liquid first refrigerant flow of the fourth cooling flows across a Joule-Thomson valve such that a temperature of the first refrigerant flow drops due to a Joule-Thomson effect;   directing a two-phase mixture of the first refrigerant flow to fourth warming flows of the one or more heat exchangers to vaporize the liquid and heat the fluid of the first refrigerant flow to near-ambient conditions of a second refrigerant flow of the fourth warming flows;   providing a fifth stream not mixed with each of the first stream, the second stream, the third stream and the fourth stream, the fifth stream having a second refrigerant of primarily nitrogen having the ambient temperature of between 60 to 150 degrees F. and a high pressure of between 700 and 1200 psia;   cooling the fifth stream through fifth cooling flows by the one or more heat exchangers;   removing a first flow portion of the fifth stream by a splitter from a first refrigerant flow of the fifth cooling flows at a first temperature of between 0 and 60 degrees F.;   removing a second remainder flow portion of the fifth stream by the splitter from the first refrigerant flow of the fifth cooling flows at a second and relatively colder temperature than the first temperature of between −160 and −100 degrees F.; and   feeding each of the first flow portion and a cooled flow of the second flow portion of the fifth stream into expanders that mechanically use a shaft to power fifth compressors to reduce a temperature of the fifth stream to serve as fifth warming flows.   
     
     
         16 . The method of  claim 15 , further comprising compressing and cooling the second refrigerant flow of the fourth stream through at least one compressor and cooling stage and returned to the fourth cooling flow. 
     
     
         17 . The method of  claim 15 , further comprising transferring work energy from fluid of each of the first flow portion and the cooled flow into a shaft which powers the fifth compressors. 
     
     
         18 . The method of  claim 15 , further comprising performing a turndown operation of the system including reducing a mass flow of the fifth stream by reducing pressure of the second refrigerant by a selected percentage that is based on a percentage of a desired turndown flowrate. 
     
     
         19 . The method of  claim 18 , wherein the turndown operation includes reducing a system flowrate to below one of 30%, 70% or 80% of a full load flowrate the system is capable of running at. 
     
     
         20 . The method of  claim 18 , wherein the turndown operation includes reducing a pressures of the fifth stream at a pressure release valve by releasing coolant, cryogenic fluid or nitrogen of the fifth stream to lower electrical power needed by a compressor to perform compression of the fifth stream. 
     
     
         21 . The method of  claim 15 , wherein the first refrigerant is nitrogen and the second refrigerant is methane; and wherein none of the liquid, gas or chemical in the fourth stream is combined or mixed with that of the fifth stream.