System and process for natural gas liquefaction

Abstract

Systems and processes for natural gas processing, liquefaction, and storage are described. The systems and processes include one or more arrangements of features which are capable of liquefying all of the gas entering an inlet of the system or a portion of the entering gas. The portion of the entering gas that is liquefied can vary based on the pressure of an outlet of the system, which can be fixed or vary based on usage downstream.

1 . A system for natural gas processing, liquefaction, and/or storage, comprising:
 one or more natural gas inlet;   structure configured for containing, processing, and/or storing all or a portion of natural gas received by one or more of the inlets, the structure comprising:
 one or more contaminant removal systems; 
 one or more heat exchanger; 
 one or more compressors; 
 one or more expanders or JT valves; 
 one or more gas storage unit and/or separator; and/or 
 one or more control valves; 
   one or more gas outlet; and   a controller in direct or indirect operable communication with one or more of the inlets, all or a portion of the structure, and/or one or more of the outlets;   wherein the controller is operably configured for controlling operation of one or more of the inlets, all or a portion of the structure, and/or one or more of the outlets in a manner to provide for either: (i) liquefaction of all of the natural gas received, except for waste gas or a fuel gas source, or (ii) liquefaction of a portion of the natural gas received, the controlling being based on pressure of gas in one or more of the gas outlets.   
     
     
         2 . The system of  claim 1 , wherein the controller is configured to separate all or a portion of gas received from one or more of the inlets, and optionally exiting one or more of the contaminant removal systems, into a product stream and a primary refrigeration stream. 
     
     
         3 . The system of  claim 2 , wherein the controller is configured to direct all or a portion of gas of the primary refrigeration stream to circulate within the primary refrigeration stream in a closed loop. 
     
     
         4 . The system of  claim 2 , wherein the controller is configured to direct all or a portion of gas of the primary refrigeration stream to mix with all or a portion of gas received from one or more of the inlets, and optionally exiting one or more of the contaminant removal systems. 
     
     
         5 . The system of  claim 1 , wherein one or more of the contaminant removal systems comprises a carbon dioxide removal system, and the controller is configured to direct all or a portion of gas to the carbon dioxide removal system and/or to a primary refrigeration stream. 
     
     
         6 . The system of  claim 5 , wherein the controller is configured to direct all or a portion of gas entering the primary refrigeration stream to stay and circulate in the primary refrigeration stream in a closed loop or exit through one or more of the gas outlets. 
     
     
         7 . The system of  claim 5 , wherein the controller is configured to direct all or a portion of gas entering the primary refrigeration stream to stay and circulate in the primary refrigeration stream in a closed loop, to return and mix with all or a portion of gas received from one or more of the inlets, or to exit through one or more of the gas outlets. 
     
     
         8 . A process for natural gas processing, liquefaction, and/or storage, comprising:
 inputting a natural gas stream through one or more contaminant removal systems to provide a cleaned gas stream;   compressing, expanding, and/or inputting through a heat exchanger the cleaned gas stream to provide a plurality of streams of gas comprising:
 a product stream; and 
 primary and secondary refrigeration streams; 
   circulating the primary refrigeration stream such that it is capable of flowing in a closed loop, and/or recirculating to mix with the cleaned gas stream, and/or exiting the process through an outlet; and   liquefying and storing gas from the product stream in a gas storage tank and separator.   
     
     
         9 . The process of  claim 8 , further comprising directing the primary and secondary refrigeration streams to flow through the heat exchanger in a direction opposite that of the product stream. 
     
     
         10 . The process of  claim 8 , further comprising inputting a boil off gas stream from the gas storage tank and separator through the heat exchanger. 
     
     
         11 . The process of  claim 10 , further comprising directing the boil off gas stream to flow through the heat exchanger in a direction which is opposite that of the product stream. 
     
     
         12 . The process of  claim 11 , further comprising mixing the boil off gas stream with the secondary refrigeration stream to provide a mixed stream of gas. 
     
     
         13 . The process of  claim 8 , further comprising compressing the product stream prior to the inputting of the product stream through the heat exchanger. 
     
     
         14 . The process of  claim 8 , further comprising inputting a pre-refrigeration stream through the heat exchanger and expanding the pre-refrigeration stream through a turbo expander to provide the primary refrigeration stream. 
     
     
         15 . The process of  claim 8 , further comprising compressing the primary refrigeration stream through a turbo compressor upon exiting the heat exchanger. 
     
     
         16 . The process of  claim 8 , further comprising directing the product stream through one or more JT valves upon exiting the heat exchanger thereby reducing the pressure of the product stream to provide liquefied natural gas for storage and/or to provide the secondary refrigeration stream. 
     
     
         17 . The process of  claim 12 , further comprising directing the mixed stream of gas through the heat exchanger. 
     
     
         18 . The process of  claim 17 , further comprising compressing the mixed stream of gas by way of one or more compressors upon exiting the heat exchanger. 
     
     
         19 . The process of  claim 18 , wherein the one or more compressors increase the pressure of the mixed stream of gas such that it reaches the pressure of the inputted natural gas stream. 
     
     
         20 . The process of  claim 19 , further comprising directed the mixed stream of gas exiting the one or more compressors to provide fuel gas to one or more ancillary systems.