System and method for harnessing energy from a pressurized gas flow to produce lng

Abstract

A system includes a heat exchanger including a first inlet for receiving a first pressurized gas stream and a first outlet for outputting a chilled gas stream produced by the heat exchanger cooling the first pressurized gas stream. The system also includes a turbo expander connected to the first outlet of the heat exchanger for receiving the chilled gas stream from the heat exchanger and producing a partially liquified gas stream, the partially liquified gas stream comprising vapors and LNG. The system further includes at least one separator connected to the turbo expander, wherein the partially liquified gas stream is fed into the at least one separator, and the at least one separator separates the vapors from the LNG.

What is claimed is: 
     
         1 . A system, comprising:
 a heat exchanger comprising:
 a first inlet for receiving a first pressurized gas stream; and 
 a first outlet for outputting a chilled gas stream produced by the heat exchanger cooling the first pressurized gas stream; 
   a turbo expander connected to the first outlet of the heat exchanger for receiving the chilled gas stream from the heat exchanger and producing a partially liquified gas stream, the partially liquified gas stream comprising vapors and LNG; and   at least one separator connected to the turbo expander, wherein the partially liquified gas stream is fed into the at least one separator, and the at least one separator separates the vapors from the LNG.   
     
     
         2 . The system of  claim 1 , wherein the heat exchanger further comprises:
 at least one vapor inlet in the heat exchanger connected to the at least one separator for receiving vapors from the at least one separator.   
     
     
         3 . The system of  claim 2 , further comprising:
 at least one vapor outlet for outputting the vapors from the heat exchanger; and   at least one compressor connected between the at least one vapor outlet of the heat exchanger and a pipeline for compressing the vapors output from the heat exchanger to a pressure suitable for the pipeline.   
     
     
         4 . The system of  claim 3 , wherein the turbo expander is coupled to the at least one compressor, wherein the turbo expander supplies power to the at least one compressor. 
     
     
         5 . The system of  claim 3 , further comprising a cooler connected between the at least one compressor and the pipeline. 
     
     
         6 . The system of  claim 3 , wherein:
 the at least one compressor is a multi-stage compression assembly comprising multiple compressors connected in series; and   the at least one separator is a multi-stage separation assembly comprising multiple separators connected in series.   
     
     
         7 . The system of  claim 6 , wherein:
 the at least one vapor inlet comprises multiple vapor inlets each connected to one of the multiple separators;   the at least one vapor outlet comprises multiple vapor outlets each connected between a corresponding one of the multiple vapor inlets and a corresponding one of the multiple compressors; and   at least one interstage vapor mixer is connected between one of the multiple vapor outlets and the corresponding one of the multiple compressors for mixing vapors output from the one of the multiple vapor outlets with compressed vapors output from an adjacent compressor.   
     
     
         8 . The system of  claim 1 , further comprising:
 a feed splitter upstream of the heat exchanger for splitting an initial gas stream into the first pressurized gas stream and a second pressurized gas stream;   a second turbo expander connected between the feed splitter and a second inlet of the heat exchanger, wherein the second turbo expander receives the second pressurized gas stream and outputs an expanded gas stream to the second inlet; and   a pipeline connected to a second outlet of the heat exchanger, the second outlet outputting a heated gas stream produced by the heat exchanger heating the expanded gas stream.   
     
     
         9 . The system of  claim 8 , further comprising at least one compressor connected between the heat exchanger and the pipeline for providing compressed gas to the pipeline,
 wherein the heat exchanger further comprises:
 at least one vapor inlet for receiving vapors from the at least one separator; and 
 at least one vapor outlet for outputting the vapors from the heat exchanger, wherein the at least one compressor is connected to the at least one vapor outlet. 
   
     
     
         10 . The system of  claim 9 , wherein the at least one compressor is coupled to one or both of the turbo expander and the second turbo expander, wherein one or both of the turbo expander and the second turbo expander supplies power to the at least one compressor. 
     
     
         11 . A method, comprising:
 receiving a first pressurized gas stream into a heat exchanger;   cooling the first pressurized gas stream via the heat exchanger to produce a chilled gas stream output from the heat exchanger;   expanding the chilled gas stream via a turbo expander connected to the first outlet to produce a partially liquified gas stream comprising vapors and LNG; and   separating the vapors from the LNG via a separator connected to the turbo expander.   
     
     
         12 . The method of  claim 11 , further comprising:
 receiving the vapors from the at least one separator into at least one vapor inlet of the heat exchanger; and   cooling the first pressurized gas stream via heat transfer between the first pressurized gas stream and the vapors in the heat exchanger.   
     
     
         13 . The method of  claim 12 , further comprising:
 outputting the vapors from the heat exchanger via at least one vapor outlet of the heat exchanger; and   compressing the vapors output from the heat exchanger via at least one compressor to output a compressed gas toward a pipeline at a pressure suitable for the pipeline.   
     
     
         14 . The method of  claim 13 , further comprising supplying power generated by the turbo expander to the at least one compressor for operating the at least one compressor. 
     
     
         15 . The method of  claim 13 , further comprising cooling the compressed gas output from the at least one compressor via a cooler connected between the at least one compressor and the pipeline. 
     
     
         16 . The method of  claim 13 , wherein:
 the at least one compressor is a multi-stage compression assembly comprising multiple compressors connected in series; and   the at least one separator is a multi-stage separation assembly comprising multiple separators connected in series.   
     
     
         17 . The method of  claim 16 , wherein:
 the at least one vapor inlet comprises multiple vapor inlets each connected to one of the multiple separators;   the at least one vapor outlet comprises multiple vapor outlets each connected between a corresponding one of the multiple vapor inlets and a corresponding one of the multiple compressors; and   the method further comprises mixing vapors output from the one of the multiple vapor outlets with compressed vapors output from a compressor adjacent the corresponding one of the multiple compressors.   
     
     
         18 . The method of  claim 11 , further comprising:
 splitting an initial gas stream into the first pressurized gas stream and a second pressurized gas stream;   reducing a pressure of the second pressurized gas stream via a second turbo expander to produce an expanded gas stream provided to the heat exchanger;   cooling the first pressurized gas stream via heat transfer between the first pressurized gas stream and the expanded gas stream in the heat exchanger; and   outputting a heated gas stream produced by the heat exchanger heating the expanded gas stream toward a pipeline at a pressure suitable for the pipeline.   
     
     
         19 . The method of  claim 18 , further comprising:
 receiving vapors from the at least one separator into the heat exchanger;   outputting the vapors from the heat exchanger after the vapors are heated; and   compressing the vapors output from the heat exchanger via at least one compressor to output a compressed gas toward the pipeline at the pressure suitable for the pipeline.   
     
     
         20 . The system of  claim 19 , further comprising:
 supplying power generated by one or both of the turbo expander and the second turbo expander to the at least one compressor for operating the at least one compressor.