System and method for precooling in hydrogen or helium liquefaction processing

Abstract

Described herein are systems and processes for precooling hydrogen or helium gas streams for liquefaction using liquid nitrogen having reduced energy consumption and amount of liquid nitrogen usage. The systems include a stream of pressurized liquid nitrogen, at least one turboexpander, and at least one heat exchanger.

What is claimed: 
     
         1 . A method for precooling hydrogen or helium gas using a liquid nitrogen stream, the method comprising:
 a. providing a pressurized liquid nitrogen stream containing liquid nitrogen at a pressure between about 15 bar(a) and about 70 bar(a);   b. passing the pressurized liquid nitrogen stream and a partially-cooled hydrogen or helium gas stream through a first heat exchanger that exchanges heat between the pressurized liquid nitrogen stream and the partially-cooled hydrogen or helium gas stream to provide a first partially-warmed nitrogen stream and a precooled hydrogen or helium gas stream;   c. passing the first partially-warmed nitrogen stream through one or more turboexpanders that lowers the temperature and pressure of the partially-warmed nitrogen stream to provide a cold nitrogen stream; and   d. passing the cold nitrogen stream through the first heat exchanger and through a second heat exchanger to provide the precooled hydrogen or helium gas stream, and a fully-warmed nitrogen gas stream.   
     
     
         2 . The method of  claim 1 , wherein step (d) comprises: passing the cold nitrogen stream through the first heat exchanger that exchanges heat between the cold nitrogen stream and the partially-cooled hydrogen or helium gas stream to provide a second partially-warmed nitrogen gas stream and the precooled hydrogen or helium gas stream; and passing the second partially-warmed nitrogen gas stream through the second heat exchanger that exchanges heat between the second partially-warmed nitrogen gas stream and a warm hydrogen or helium gas stream to provide a fully-warmed nitrogen gas stream and the partially-cooled hydrogen or helium gas stream. 
     
     
         3 . The method of  claim 2 , wherein the first heat exchanger and the second heat exchanger are separate devices. 
     
     
         4 . The method of  claim 1 , wherein the first heat exchanger and the second heat exchanger are parts within a single heat exchanger. 
     
     
         5 . The method of  claim 1 , wherein the pressurized liquid nitrogen has a pressure between about 15 bar(a) and about 70 bar(a). 
     
     
         6 . The method of  claim 1 , wherein the pressurized liquid nitrogen has a pressure between about 20 bar(a) and about 55 bar(a). 
     
     
         7 . The method of  claim 1 , wherein step (a) includes the steps of: supplying a liquid nitrogen stream produced at a saturation pressure of less than about 10 bar(a); followed by increasing the pressure of the liquid nitrogen stream to provide the pressurized liquid nitrogen stream. 
     
     
         8 . The method of  claim 1 , wherein step (a) includes the steps of: supplying a liquid nitrogen stream produced at a saturation pressure of less than about 10 bar(a); splitting the liquid nitrogen stream into a first portion of the liquid nitrogen stream and a second portion of the liquid nitrogen stream; and increasing a pressure of the first portion of the liquid nitrogen stream to provide the pressurized liquid nitrogen stream. 
     
     
         9 . The method of  claim 8 , further comprising passing the second portion of the liquid nitrogen stream through the first heat exchanger to provide a third partially-warmed nitrogen stream 
     
     
         10 . The method of  claim 9 , further comprising directing the third partially-warmed nitrogen stream through the second heat exchanger to provide a second fully-warmed nitrogen gas stream. 
     
     
         11 . The method of  claim 1 , further comprising applying an auxiliary refrigeration system coupled to the second heat exchanger. 
     
     
         12 . The method of  claim 2 , wherein the pressurized liquid nitrogen stream is split into a first pressurized liquid nitrogen stream and a second pressurized liquid nitrogen stream, and wherein the first pressurized liquid nitrogen stream and the second pressurized liquid nitrogen stream are passed separately through the first heat exchanger to exchange heat between the first and the second pressurized liquid nitrogen streams and the partially-cooled hydrogen or helium gas stream. 
     
     
         13 . The method of  claim 1 , wherein step (c) includes passing the first partially-warmed nitrogen stream through one or two turboexpanders. 
     
     
         14 . The method of  claim 1 , wherein step (c) includes passing the first partially-warmed nitrogen stream through one or more compressors before passing through the one or more turboexpanders. 
     
     
         15 . The method of  claim 2 , further comprising applying an auxiliary refrigeration system coupled to the second heat exchanger. 
     
     
         16 . A method for precooling hydrogen or helium gas using a liquid nitrogen stream, the method comprising:
 a. supplying a liquid nitrogen stream produced at a saturation pressure of less than about 10 bar(a);   b. directing a first portion of the liquid nitrogen stream to a first heat exchanger to provide a first partially-warmed nitrogen stream;   c. directing the first partially-warmed nitrogen stream to a second heat exchanger to provide a first fully-warmed nitrogen gas stream;   d. increasing a pressure of a second portion of the liquid nitrogen stream to provide a pressurized liquid nitrogen stream at a pressure between about 15 bar(a) and about 70 bar(a);   e. passing the pressurized liquid nitrogen stream and a partially-cooled hydrogen or helium gas stream through the first heat exchanger in countercurrent to provide a second partially-warmed nitrogen gas stream and a precooled hydrogen or helium gas stream;   f. passing the second partially-warmed nitrogen gas stream through the second heat exchanger that exchanges heat between the second partially-warmed nitrogen gas stream and a warm hydrogen or helium gas stream to provide a second fully-warmed nitrogen gas stream and the partially-cooled hydrogen or helium gas stream;   g. passing the second fully-warmed nitrogen gas stream through one or more turboexpanders that lower the temperature and pressure of the second fully-warmed nitrogen gas stream to provide a cold nitrogen stream;   h. passing the cold nitrogen stream through the first heat exchanger that exchanges heat between the cold nitrogen stream and the partially-cooled hydrogen or helium gas stream to provide a third partially-warmed nitrogen gas stream and the precooled hydrogen or helium gas stream; and   i. passing the third partially-warmed nitrogen gas stream through the second heat exchanger that exchanges heat between the third partially-warmed nitrogen gas stream and a warm hydrogen or helium gas stream to provide a third fully-warmed warm nitrogen gas stream and the partially-cooled hydrogen or helium gas stream.   
     
     
         17 . The method of  claim 16 , wherein step (g) comprises: routing the second fully-warmed nitrogen stream through one or more compressors and one or more coolers before passing the second fully-warmed nitrogen stream through the one or more turboexpanders. 
     
     
         18 . The method of  claim 16 , wherein step (g) includes passing the second fully-warmed nitrogen stream through two turboexpanders connected in series. 
     
     
         19 . The method of  claim 16 , wherein the pressurized liquid nitrogen stream is split into a first pressurized liquid nitrogen stream and a second pressurized liquid nitrogen stream; and wherein the first pressurized liquid nitrogen stream and the second pressurized liquid nitrogen stream are routed separately through the first heat exchanger. 
     
     
         20 . The method of  claim 16 , wherein the first heat exchanger and the second heat exchanger are separate devices. 
     
     
         21 . The method of  claim 16 , wherein the first heat exchanger and the second heat exchanger are parts within a single heat exchanger. 
     
     
         22 . The method of  claim 16 , further comprising applying an auxiliary refrigeration system coupled to the second heat exchanger. 
     
     
         23 . The method of  claim 16 , further including a system of recooling the second or third fully-warmed nitrogen gas stream, the system of recooling comprising:
 i. passing the second or third fully-warmed nitrogen gas stream through a first compressor and a first cooler to obtain a compressed and cooled nitrogen gas stream, wherein the first compressor is coupled to the second heat exchanger and to the first cooler; and   ii. passing the compressed and cooled nitrogen gas stream through one or more turboexpanders; and   iii. passing the turboexpanded nitrogen gas stream through the second heat exchanger to provide a fourth fully-warmed nitrogen gas stream.   
     
     
         24 . The method of  claim 23 , wherein step (ii) includes passing the compressed and cooled nitrogen gas stream through two turboexpanders connected in series. 
     
     
         25 . A precooling system using liquid nitrogen for hydrogen or helium liquefaction, the system comprising:
 a warm hydrogen or helium gas stream;   a pressurized liquefied nitrogen stream from a supply of liquefied nitrogen;   a heat exchanger configured to exchange heat between the pressurized liquefied nitrogen stream and a warm hydrogen or helium gas stream to increase a temperature of the pressurized liquefied nitrogen stream to provide a warm nitrogen gas stream, and decrease a temperature of the warm hydrogen or helium gas stream to provide a precooled nitrogen gas stream; and   at least one turboexpander coupled to the heat exchanger and configured to lower a temperature of a partially-warmed nitrogen gas stream discharged from the heat exchanger.   
     
     
         26 . The precooling system of  claim 25 , further comprising at least one compressor and at least one cooler configured to receive the warm nitrogen gas stream discharged from the heat exchanger. 
     
     
         27 . The precooling system of  claim 26 , further comprising at least one turboexpander configured to receive the warm nitrogen gas stream after passage through the at least one compressor and the at least one cooler. 
     
     
         28 . The precooling system of  claim 26 , further comprises a valve coupled to the turboexpander configured to reduce the pressure of the nitrogen gas stream. 
     
     
         29 . A precooling system using liquid nitrogen for hydrogen or helium liquefaction, the system comprising:
 a warm hydrogen gas stream or helium gas stream;   a pressurized liquefied nitrogen stream from a supply of liquefied nitrogen;   a first heat exchanger configured to exchange heat between the pressurized liquefied nitrogen stream and a partially-cooled hydrogen or helium gas stream to increase a temperature of the pressurized liquefied nitrogen stream to provide a partially-warmed nitrogen gas stream, and decrease a temperature of the partially-cooled hydrogen or helium gas stream;   at least one turboexpander configured to lower the temperature of the partially-warmed nitrogen gas stream; and   a second heat exchanger configured to exchange heat between the partially-warmed nitrogen gas stream and the warm hydrogen or helium gas stream to increase a temperature of the partially-warmed nitrogen gas stream to provide a fully-warmed nitrogen gas stream, and to decrease a temperature of the warm hydrogen or helium gas stream.   
     
     
         30 . The precooling system of  claim 29 , further comprising at least one compressor and at least one cooler configured to receive the fully-warmed nitrogen gas stream after passage through the second heat exchanger.