Method for the production of liquefied natural gas

Abstract

A method for the production of liquefied natural gas (LNG) without the use of externally provided electricity is provided The method may include the steps of: providing a transportable apparatus, wherein the transportable apparatus comprises a housing, a heat exchanger, a phase separator, a first refrigeration supply, and a second refrigeration supply, wherein the first refrigeration supply and the second refrigeration supply are configured to provide refrigeration within the heat exchanger; introducing a natural gas stream into the transportable apparatus at a first pressure under conditions effective for producing an LNG stream; withdrawing the LNG stream from the transportable apparatus; and withdrawing a warm natural gas stream from the transportable apparatus, wherein the warm natural gas stream is at a second pressure, wherein the second pressure is lower than the first pressure.

I claim: 
     
         1 . A method for the production of liquefied natural gas (“LNG”) using a transportable apparatus, the method comprising the steps of:
 providing a transportable apparatus, wherein the transportable apparatus comprises a housing, a heat exchanger, a phase separator, a first refrigeration supply, and a second refrigeration supply, wherein the first refrigeration supply and the second refrigeration supply are configured to provide refrigeration within the heat exchanger; 
 introducing a natural gas stream into the transportable apparatus at a first pressure under conditions effective for producing an LNG stream; 
 withdrawing the LNG stream from the transportable apparatus; and 
 withdrawing a warm natural gas stream from the transportable apparatus, wherein the warm natural gas stream is at a second pressure, wherein the second pressure is lower than the first pressure. 
 
     
     
         2 . The method as claimed in  claim 1 , wherein the first refrigeration supply comprises a first expansion valve, a first LNG inlet disposed on a cold end of the heat exchanger, and a first natural gas outlet disposed on a warm end of the heat exchanger, wherein the first refrigeration supply is in fluid communication with a liquid outlet disposed on the cold end of the heat exchanger, wherein the heat exchanger is configured to indirectly exchange heat between a first LNG stream and the natural gas stream when the first LNG stream flows from the first LNG inlet to first natural gas outlet. 
     
     
         3 . The method as claimed in  claim 2 , wherein the second refrigeration supply comprises a liquid nitrogen inlet disposed on the cold end of the heat exchanger and a nitrogen outlet disposed on the warm end of the heat exchanger, and wherein the heat exchanger is configured to indirectly exchange heat between a liquid nitrogen fluid and the natural gas stream when the liquid nitrogen flows from the liquid nitrogen inlet to the nitrogen outlet. 
     
     
         4 . The method as claimed in  claim 3 , wherein the second refrigeration supply further comprises a liquid nitrogen storage tank in fluid communication with the liquid nitrogen inlet, such that the liquid storage tank is configured to deliver liquid nitrogen to the heat exchanger via the liquid nitrogen inlet. 
     
     
         5 . The method as claimed in  claim 2 , wherein the second refrigeration supply comprises a second expansion valve, a second LNG inlet disposed on the cold end of the heat exchanger, and a second natural gas outlet disposed on the warm end of the heat exchanger, and wherein the heat exchanger is configured to indirectly exchange heat between a second LNG stream and the natural gas stream when the second LNG stream flows from the second LNG inlet to second natural gas outlet. 
     
     
         6 . The method as claimed in  claim 5 , wherein the first expansion valve is configured to expand the first LNG stream to a first LNG pressure, wherein the second expansion valve is configured to expand the second LNG stream to a second LNG pressure, wherein the first LNG pressure is higher than the second LNG pressure. 
     
     
         7 . The method as claimed in  claim 6 , wherein the first LNG pressure is between 4 and 10 bara, wherein the second LNG pressure is between 1 to 2 bara. 
     
     
         8 . The method as claimed in  claim 1 , wherein portable apparatus further comprises a natural gas feed inlet configured to accept a stream of pressurized natural gas originating from outside the housing,
 wherein the heat exchanger is in fluid communication with the natural gas feed inlet, such that the heat exchanger is configured to receive the stream of pressurized natural gas from the natural gas feed inlet, wherein the heat exchanger has a warm end, a cold end, and an intermediate section,   wherein phase separator has a fluid inlet, a gaseous outlet, and a liquid outlet, wherein the fluid inlet is in fluid communication with a first intermediate fluid outlet located in the intermediate section of the heat exchanger, such that the phase separator is configured to receive a partially cooled fluid from the heat exchanger, wherein the liquid outlet of the phase separator is in fluid communication with a first intermediate fluid inlet of the intermediate section of the heat exchanger, wherein the gaseous outlet of the phase separator is in fluid communication with a second intermediate fluid inlet of the intermediate section of the heat exchanger, such that the second intermediate fluid inlet of the intermediate section of the heat exchanger is configured to receive at least a first portion of gas coming from the phase separator,   wherein the transportable apparatus further comprises a third intermediate fluid inlet of the intermediate section of the heat exchanger that is configured to receive a second portion of gas coming from the phase separator.   
     
     
         9 . The method as claimed in  claim 8 , further comprising a third expansion valve in fluid communication with, and disposed inline between, the gaseous outlet of the phase separator and a second intermediate fluid inlet of the intermediate section of the heat exchanger. 
     
     
         10 . The method as claimed in  claim 8 , further comprising a lower pressure natural gas outlet in fluid communication with the first natural gas outlet of the heat exchanger, wherein the lower pressure natural gas outlet is configured to send a stream warm natural gas received from the first natural gas outlet to outside of the housing. 
     
     
         11 . The method as claimed in  claim 8 , further comprising a liquid expansion valve in fluid communication with, and disposed inline between, the liquid outlet of the phase separator and the first intermediate fluid inlet of the intermediate section of the heat exchanger; 
     
     
         12 . The method as claimed in  claim 8 , wherein the heat exchanger is split into a first portion and a second portion, wherein the warm end of the heat exchanger is disposed in the first portion, wherein the cold end of the heat exchanger is disposed in the second portion, wherein the intermediate section is disposed in both the first portion and the second portion. 
     
     
         13 . The method as claimed in  claim 1 , further comprising an absence of compressing the natural gas stream within the transportable apparatus. 
     
     
         14 . The method as claimed in  claim 1 , wherein the transportable apparatus comprises an absence of a rotating compressor. 
     
     
         15 . The method as claimed in  claim 1 , wherein the transportable apparatus comprises an absence of rotating machinery. 
     
     
         16 . The method as claimed in  claim 1 , wherein the transportable apparatus comprises an absence of electrically powered compression or expansion devices. 
     
     
         17 . The method as claimed in  claim 1 , further comprising an absence of a step of providing external electric power to the transportable apparatus. 
     
     
         18 . The method as claimed in  claim 1 , wherein the step of providing the transportable apparatus comprises loading the transportable apparatus on a truck or barge and transporting the transportable apparatus from a first location to a second location. 
     
     
         19 . The method as claimed in  claim 1 , wherein the heat exchanger, the phase separator, the first refrigeration supply, and the second refrigeration supply are all disposed within the housing. 
     
     
         20 . The method as claimed in  claim 1 , wherein the combined flow rates of refrigerant through the first refrigeration supply and the second refrigeration supply are less than 10% of the flow of the natural gas stream into the transportable apparatus at the first pressure. 
     
     
         21 . The method as claimed in  claim 1 , wherein the warm natural gas stream at the second pressure is burned as fuel in a purification unit.