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;   splitting the cleaned gas stream into a pre-refrigeration stream and a product stream;   passing the product stream through a compressor, and then a heat exchanger, and then splitting a secondary refrigeration stream off of the product stream; liquefying and storing gas from the product stream in a gas storage tank;   prior to any expansion or compression of the pre-refrigeration stream, inputting the pre-refrigeration stream through the heat exchanger then expanding the pre-refrigeration stream to provide the primary refrigeration stream and circulating the primary refrigeration stream in a manner to flow in a closed loop, and/or to recirculate and mix with the cleaned gas stream, and/or to exit the process through an outlet.   
     
     
         9 . The process of  claim 8 , further comprising directing the primary refrigeration stream and the secondary refrigeration stream to flow through the heat exchanger. 
     
     
         10 . The process of  claim 9 , further comprising inputting a boil off gas stream from the gas storage tank through the heat exchanger. 
     
     
         11 . The process of  claim 10 , further comprising after directing the boil off gas stream to flow through the heat exchanger, then sending the boil off gas stream to provide fuel gas to one or more ancillary systems, optionally compressing the boil off gas stream. 
     
     
         12 . The process of  claim 10 , further comprising after passing the boil off gas stream through the heat exchanger, optionally compressing the boil off gas stream, then mixing the boil off gas stream with the secondary refrigeration stream to provide a mixed stream of gas. 
     
     
         13 . (canceled) 
     
     
         14 . The process of  claim 8 , wherein the expanding of the pre-refrigeration stream after passing through the heat exchanger is performed by passing the pre-refrigeration stream through a turbo expander to provide the primary refrigeration stream. 
     
     
         15 . The process of  claim 14 , further comprising compressing the primary refrigeration stream through a turbo compressor. 
     
     
         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 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 mixing the secondary refrigeration stream with a boil off gas stream from the gas storage tank to form a mixed stream of gas, and then directing the mixed stream of gas through the heat exchanger. 
     
     
         18 . The process of  claim 17 , further comprising after directing the mixed stream of gas through the heat exchanger, then directing the mixed stream of gas to the outlet or to provide fuel gas to one or more ancillary systems, optionally compressing the mixed stream of gas by way of one or more compressors. 
     
     
         19 . The process of  claim 18 , wherein the one or more compressors increase the pressure of the mixed stream of gas such that the mixed stream of gas reaches the pressure of the inputted natural gas stream or the pressure of an outlet natural gas stream. 
     
     
         20 . The process of  claim 18 , further comprising after the compressing of the mixed stream of gas, directing the compressed mixed stream of gas to provide fuel gas to one or more of the ancillary systems. 
     
     
         21 . The process of  claim 12 , further comprising after mixing the boil off gas stream with the secondary refrigeration stream, then directing the mixed stream of gas to the outlet, optionally further compressing the mixed stream of gas before exiting the process.