System and method for hybrid refrigeration gas liquefaction

Abstract

In an embodiment, a method includes cooling a fluid along a fluid path using a vapor compression refrigeration cycle; cooling the fluid along the fluid path using at least one cryocooler of a cryogenic cooling phase; expanding the fluid during cooling within the cryogenic cooling phase, after cooling in the cryogenic cooling phase, or a combination thereof, such that a temperature and pressure of the fluid are reduced to generate a fluid stream having both a vapor phase and a liquid phase; and condensing the vapor phase. The fluid may be a natural gas.

1 . A gas feed liquefaction system, comprising:
 a flow path;   an initial cooling phase in a first heat exchange relationship with the flow path, wherein the initial cooling phase comprises a vapor compression refrigeration cycle;   a second cooling phase in a second heat exchange relationship with the flow path, wherein the second cooling phase comprises a first cryocooler in series with the initial cooling phase; and   a first expander positioned along the flow path between the first cryocooler and a separation vessel comprising a first liquid outlet and a vapor outlet.   
     
     
         2 . The system of  claim 1 , comprising a first heat exchanger placing the flow path and the initial cooling phase in the first heat exchange relationship, and a second heat exchanger heat-integrating the initial cooling phase and the first cryocooler or an additional cryocooler of the gas feed liquefaction system. 
     
     
         3 . The system of  claim 1 , comprising a third cooling phase having a second cryocooler positioned downstream of the vapor outlet of the separation vessel, wherein the first and second cryocoolers are driven using a single driver. 
     
     
         4 . The system of  claim 3 , comprising a liquid product outlet path, wherein the liquid product outlet path comprises a mixer comprising first and second inlets in fluid communication with the first liquid outlet of the separation vessel and a second liquid outlet of the second cryocooler. 
     
     
         5 . The system of  claim 3 , wherein the first and second cryocoolers share a common buffer tube and a common compliance tank. 
     
     
         6 . The system of  claim 1 , wherein the second cooling phase comprises a second cryocooler positioned along the flow path between the first cryocooler and the separation vessel, wherein the first expander is positioned between the first and second cryocoolers, or between the second cryocooler and the separation vessel. 
     
     
         7 . The system of  claim 6 , comprising a driver configured to power the first and second cryocoolers, wherein the first and second cryocoolers are connected via a common buffer tube. 
     
     
         8 . The system of  claim 1 , wherein the flow path splits into a plurality of intermediate flow paths arranged in a parallel relationship, the first cryocooler is positioned along a first one of the intermediate flow paths, the second cooling phase comprises a second cryocooler positioned along a second one of the intermediate flow paths, and the first and second cryocoolers are driven by a common driver, are connected by a common buffer tube, and the first and second cryocoolers both use the same compliance tank. 
     
     
         9 . The system of  claim 8 , comprising:
 a third cryocooler positioned along the first one of the intermediate flow paths in series with the first cryocooler, wherein the first expander is positioned along the first one of the intermediate flow paths between the first and third cryocoolers;   a fourth cryocooler positioned along the second one of the intermediate flow paths in series with the second cryocooler; and   a second expander positioned along the second one of the intermediate flow paths between the second and fourth cryocoolers.   
     
     
         10 . The system of  claim 1 , wherein at least one of the heat exchangers within the vapor compression refrigeration cycle places the refrigeration loop of the vapor compression refrigeration cycle in the first heat exchange relationship with a working fluid in at least one of the first and second thermoacoustic cryocoolers. 
     
     
         11 . The system of  claim 1 , wherein the initial cooling phase is downstream from a natural gas processing facility or gasification plant. 
     
     
         12 . A system comprising:
 a natural gas flow path;   a vapor compression refrigeration cycle configured to remove heat from the natural gas flow path;   a first cryogenic cooling phase comprising at least two cryocoolers configured to remove heat from the natural gas flow path;   a driver configured to drive the at least two cryocoolers, wherein the at least two cryocoolers are connected by a common buffer tube; and   a liquefied natural gas outlet path downstream from the vapor compression refrigeration cycle and the cryogenic cooling phase.   
     
     
         13 . The system of  claim 12 , comprising a separation vessel positioned along the natural gas flow path and having a natural gas vapor outlet and a liquefied natural gas outlet leading to the liquefied natural gas outlet path, wherein at least a portion of a second cryogenic cooling phase is positioned in fluid communication with the natural gas vapor outlet to enable the second cryogenic cooling phase to condense natural gas exiting the natural gas vapor outlet of the separation vessel. 
     
     
         14 . The system of  claim 12 , wherein at least one of heat exchanger within the vapor compression refrigeration cycle places a refrigeration loop of the vapor compression refrigeration cycle in a heat exchange relationship with a working fluid of a first cryocooler of the at least two cryocoolers. 
     
     
         15 . The system of  claim 12 , comprising an expander positioned between the at least two cryocoolers that causes natural gas to expand and cool. 
     
     
         16 . The system of  claim 12 , comprising an expander positioned between the at least two cryocoolers and the liquefied natural gas outlet path. 
     
     
         17 . A method comprising:
 cooling a fluid along a fluid path using a vapor compression refrigeration cycle;   cooling the fluid along the fluid path using at least one cryocooler of a cryogenic cooling phase;   expanding the fluid during cooling within the cryogenic cooling phase, after cooling in the cryogenic cooling phase, or a combination thereof, such that a temperature and pressure of the fluid are reduced to generate a fluid stream having both a vapor phase and a liquid phase; and   condensing the vapor phase.   
     
     
         18 . The method of  claim 17 , comprising separating the vapor phase and liquid phase from one another before condensing the vapor phase. 
     
     
         19 . The method of  claim 18 , comprising condensing the vapor phase using an additional cryogenic cooling phase. 
     
     
         20 . The method of  claim 19 , wherein the cryogenic cooling phase comprises first and second cryocoolers that are driven using the same driver, wherein the first and second cryocoolers are connected by a common buffer tube. 
     
     
         21 . The method of  claim 17 , wherein the fluid is natural gas. 
     
     
         22 . The method of  claim 17 , comprising cooling a working fluid of the cryogenic cooling phase using the vapor compression refrigeration cycle.