US2007227185A1PendingUtilityA1

Mixed Refrigerant Liquefaction Process

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Assignee: STONE JOHN BPriority: Jun 23, 2004Filed: Jun 6, 2005Published: Oct 4, 2007
Est. expiryJun 23, 2024(expired)· nominal 20-yr term from priority
Inventors:John StoneDaniel HawryszE. Lawrence Kimble
C10L 3/10F25J 1/00F25J 3/00F25J 1/0214F25J 1/0092F25J 1/0052F25J 1/0262F25J 1/0291F25B 2400/13F25B 9/006F25J 1/0292F25B 2400/12F25J 2290/32F25J 1/0022F25J 1/0042F25J 1/0097
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Claims

Abstract

A method for liquefying a natural gas stream is provided. In one embodiment, the method includes placing a mixed component refrigerant in a heat exchange area with a process stream; separating the mixed component refrigerant at one or more pressure levels to produce a refrigerant vapor and a refrigerant liquid; bypassing the refrigerant vapor around the heat exchange area to a compression unit; and passing the refrigerant liquid to the heat exchange area. In another embodiment, the method further includes partially evaporating the refrigerant liquid stream within the heat exchange area to retain a liquid fraction of at least 1% by weight.

Claims

exact text as granted — not AI-modified
1 . A method for liquefying a natural gas stream, comprising: 
 placing a mixed component refrigerant in a heat exchange area with a process stream;    separating the mixed component refrigerant at one or more pressure levels to produce a refrigerant vapor and a refrigerant liquid;    bypassing the refrigerant vapor around the heat exchange area to a compression unit;    passing the refrigerant liquid to the heat exchange area; and    partially evaporating the refrigerant liquid within the heat exchange area to retain a liquid phase.    
   
   
       2 . The method of  claim 1 , wherein the heat exchange area is contained within a single heat exchanger.  
   
   
       3 . The method of  claim 1 , wherein the heat exchange area is contained within two or more heat exchangers.  
   
   
       4 . The method of  claim 1 , wherein the heat exchange area comprises two or more areas contained within a single heat exchanger.  
   
   
       5 . The method of  claim 1 , wherein the heat exchange area comprises two or more areas wherein each area is contained within a single heat exchanger.  
   
   
       6 . The method of  claim 1 , wherein the heat exchange area comprises two or more areas contained within two or more heat exchangers.  
   
   
       7 . The method of  claim 1 , wherein the process stream consists essentially of natural gas.  
   
   
       8 . The method of  claim 1 , wherein the first mixed component refrigerant comprises ethane, propane, and isobutane.  
   
   
       9 . The method of  claim 1 , wherein the first mixed component refrigerant comprises ethane and propane.  
   
   
       10 . The method of  claim 1 , wherein the first mixed component refrigerant comprises methane, ethane and nitrogen.  
   
   
       11 . The method of  claim 1 , wherein separating the mixed component refrigerant comprises expanding the mixed component refrigerant to a pressure between about 80 kPa and about 2,600 kPa.  
   
   
       12 . The method of  claim 1 , wherein separating the mixed component refrigerant comprises expanding the mixed component refrigerant to a pressure between about 250 kPa and about 2,200 kPa.  
   
   
       13 . The method of  claim 1 , wherein separating the mixed component refrigerant comprises expanding the mixed component refrigerant to a pressure between about 500 kPa and about 1,900 kPa.  
   
   
       14 . The method of  claim 1 , wherein separating the mixed component refrigerant comprises expanding a first portion of the mixed component refrigerant to a first pressure between about 1,500 kPa and about 1,900 kPa, and expanding a second portion of the mixed component refrigerant to a second pressure between about 500 kPa and about 700 kPa.  
   
   
       15 . The method of  claim 1 , wherein separating the mixed component refrigerant comprises expanding a first portion of the mixed component refrigerant to a first pressure between about 800 kPa and about 2,600 kPa; expanding a second portion of the mixed component refrigerant to a second pressure between about 250 kPa and about 850 kPa; and expanding a third portion of the mixed component refrigerant to a third pressure between about 80 kPa and about 250 kPa.  
   
   
       16 . A method for liquefying a natural gas stream, comprising: 
 placing a mixed component refrigerant in a heat exchange area with a process stream;    withdrawing two or more side streams of the mixed component refrigerant from the heat exchange area;    separating the side streams of mixed component refrigerant at one or more pressure levels to produce refrigerant vapors and refrigerant liquids;    bypassing the refrigerant vapors around the heat exchange area to a compression unit;    passing the refrigerant liquids to the heat exchange area; and    partially evaporating the refrigerant liquids within the heat exchange area to retain a liquid phase.    
   
   
       17 . The method of  claim 16 , wherein separating the mixed component refrigerant comprises expanding the side streams of mixed component refrigerant to a pressure between about 80 kPa and about 2,600 kPa.  
   
   
       18 . The method of  claim 16 , wherein separating the mixed component refrigerant comprises expanding the side streams of mixed component refrigerant to a pressure between about 250 kPa and about 2,200 kPa.  
   
   
       19 . The method of  claim 16 , wherein separating the mixed component refrigerant comprises expanding a first side stream of mixed component refrigerant to a first pressure between about 1,500 kPa and about 1,900 kPa, and expanding a second side stream of mixed component refrigerant to a second pressure between about 500 kPa and about 700 kPa.  
   
   
       20 . The method of  claim 16 , wherein separating the mixed component refrigerant comprises expanding a first side stream of mixed component refrigerant to a first pressure between about 800 kPa and about 2,600 kPa; expanding a second side stream of mixed component refrigerant to a second pressure between about 250 kPa and about 850 kPa; and expanding a third side stream of mixed component refrigerant to a third pressure between about 80 kPa and about 250 kPa.  
   
   
       21 . The method of  claim 16 , wherein the first mixed component refrigerant comprises ethane, propane, and isobutane.  
   
   
       22 . The method of  claim 16 , wherein the first mixed component refrigerant comprises ethane and propane.  
   
   
       23 . The method of  claim 16 , wherein the first mixed component refrigerant comprises methane, ethane and nitrogen.  
   
   
       24 . The method of  claim 1 , wherein partially evaporating the refrigerant liquid within the heat exchange area retains a liquid fraction of at least 1% by weight.  
   
   
       25 . The method of  claim 24 , wherein separating the mixed component refrigerant comprises expanding the mixed component refrigerant to a pressure between about 80 kPa and about 180 kPa.  
   
   
       26 . The method of  claim 24 , wherein separating the mixed component refrigerant comprises expanding the mixed component refrigerant to a pressure between about 250 kPa and about 600 kPa.  
   
   
       27 . The method of  claim 24 , wherein separating the mixed component refrigerant comprises expanding the mixed component refrigerant to a pressure between about 800 kPa and about 1900 kPa.  
   
   
       28 . The method of  claim 24 , wherein separating the mixed component refrigerant comprises expanding a first portion of the mixed component refrigerant to a first pressure between about 1,200 kPa and about 2,200 kPa, and expanding a second portion of the mixed component refrigerant to a second pressure between about 400 kPa and about 700 kPa.  
   
   
       29 . The method of  claim 24 , wherein separating the mixed component refrigerant comprises expanding a first portion of the mixed component refrigerant to a first pressure between about 1,500 kPa and about 1,900 kPa; expanding a second portion of the mixed component refrigerant to a second pressure between about 500 kPa and about 600 kPa; and expanding a third portion of the mixed component refrigerant to a third pressure between about 150 kPa and about 180 kPa.  
   
   
       30 . The method of  claim 24 , wherein partially evaporating the refrigerant liquid produces a two-phase refrigerant having a liquid fraction of at least 1% by weight.  
   
   
       31 . The method of  claim 24 , wherein at least partially evaporating the refrigerant liquid produces a two-phase refrigerant having a liquid fraction of at least 3% by weight.  
   
   
       32 . The method of  claim 24 , wherein the process stream consists essentially of natural gas.  
   
   
       33 . The method of  claim 24 , wherein the first mixed component refrigerant comprises ethane, propane, and isobutane.  
   
   
       34 . The method of  claim 24 , wherein the first mixed component refrigerant comprises ethane and propane.  
   
   
       35 . The method of  claim 24 , wherein the first mixed component refrigerant comprises methane, ethane and nitrogen.  
   
   
       36 . A method for liquefying a natural gas stream, comprising: 
 placing a first mixed component refrigerant in a first heat exchange area with a process stream;    separating the first mixed component refrigerant at one or more pressure levels to produce a refrigerant vapor stream and a refrigerant liquid stream;    bypassing the refrigerant vapor stream around the first heat exchange area to a compression unit;    passing the refrigerant liquid stream to the first heat exchange area to cool the process stream; and    placing a second mixed component refrigerant in a second heat exchange area with the cooled process stream to liquefy the process stream.    
   
   
       37 . The method of  claim 36 , further comprising partially evaporating the refrigerant liquid stream within the first heat exchange area to retain a liquid fraction of at least 1% by weight.  
   
   
       38 . The method of  claim 36 , further comprising partially evaporating the second mixed component refrigerant within the second heat exchange area to retain a liquid fraction of at least 1% by weight.  
   
   
       39 . The method of  claim 36 , wherein separating the first mixed component refrigerant comprises expanding the first mixed component refrigerant to a pressure between about 1,200 kPa and about 2,200 kPa.  
   
   
       40 . The method of  claim 36 , wherein separating the first mixed component refrigerant comprises expanding the first mixed component refrigerant to a pressure between about 400 kPa and about 700 kPa.  
   
   
       41 . The method of  claim 36 , wherein separating the first mixed component refrigerant comprises expanding the first mixed component refrigerant to a pressure between about 120 kPa and about 200 kPa.  
   
   
       42 . The method of  claim 36 , wherein separating the first mixed component refrigerant comprises expanding a first portion of the first mixed component refrigerant to a first pressure between about 1,500 kPa and about 1,900 kPa, and expanding a second portion of the first mixed component refrigerant to a second pressure between about 500 kPa and about 600 kPa.  
   
   
       43 . The method of  claim 36 , wherein separating the first mixed component refrigerant comprises expanding a first portion of the first mixed component refrigerant to a first pressure between about 1,500 kPa and about 1,900 kPa; expanding a second portion of the first mixed component refrigerant to a second pressure between about 500 kPa and about 600 kPa; and expanding a third portion of the first mixed component refrigerant to a third pressure between about 150 kPa and about 180 kPa.  
   
   
       44 . The method of  claim 36 , wherein the process stream consists essentially of natural gas.  
   
   
       45 . The method of  claim 36 , wherein the first mixed component refrigerant comprises ethane, propane, and isobutane.  
   
   
       46 . The method of  claim 36 , wherein the first mixed component refrigerant comprises ethane and propane.  
   
   
       47 . The method of  claim 36 , wherein the second mixed component refrigerant comprises methane, ethane and nitrogen.  
   
   
       48 . A method for liquefying a natural gas stream, comprising: 
 placing a first mixed component refrigerant in a first heat exchange area with a process stream;    separating the mixed component refrigerant at one or more pressure levels to produce a refrigerant vapor stream and a refrigerant liquid stream;    bypassing the refrigerant vapor stream around the first heat exchange area to a compression unit;    returning the refrigerant liquid stream to the first heat exchange area to cool the gas stream;    placing a second mixed component refrigerant in a second heat exchange area with the cooled process stream; and    evaporating the second mixed component refrigerant at a single pressure level to liquefy the gas stream.    
   
   
       49 . The method of  claim 48 , further comprising partially evaporating the refrigerant liquid stream within the first heat exchange area to retain a liquid fraction of at least 1% by weight.  
   
   
       50 . The method of  claim 48 , further comprising partially evaporating the second mixed component refrigerant within the second heat exchange area to retain a liquid fraction of at least 1% by weight.  
   
   
       51 . The method of  claim 48 , wherein separating the first mixed component refrigerant comprises expanding the first mixed component refrigerant to a pressure between about 1,200 kPa and about 2,200 kPa.  
   
   
       52 . The method of  claim 48 , wherein separating the first mixed component refrigerant comprises expanding the first mixed component refrigerant to a pressure between about 400 kPa and about 700 kPa.  
   
   
       53 . The method of  claim 48 , wherein separating the first mixed component refrigerant comprises expanding the first mixed component refrigerant to a pressure between about 120 kPa and about 200 kPa.  
   
   
       54 . The method of  claim 48 , wherein separating the first mixed component refrigerant comprises expanding a first portion of the first mixed component refrigerant to a first pressure between about 1,500 kPa and about 1,900 kPa, and expanding a second portion of the first mixed component refrigerant to a second pressure between about 500 kPa and about 600 kPa.  
   
   
       55 . The method of  claim 48 , wherein separating the first mixed component refrigerant comprises expanding a first portion of the first mixed component refrigerant to a first pressure between about 1,500 kPa and about 1,900 kPa; expanding a second portion of the first mixed component refrigerant to a second pressure between about 500 kPa and about 600 kPa; and expanding a third portion of the first mixed component refrigerant to a third pressure between about 150 kPa and about 180 kPa.  
   
   
       56 . The method of  claim 48 , wherein evaporating the second mixed component refrigerant at a single pressure level comprises flashing the second mixed component refrigerant through a pressure reducing device to a pressure within the range of from 200 kPa to 700 kPa.  
   
   
       57 . The method of  claim 48 , wherein evaporating the second mixed component refrigerant at a single pressure level comprises flashing the second mixed component refrigerant through a valve to a pressure within the range of from 400 kPa to 500 kPa.  
   
   
       58 . The method of  claim 48 , wherein the second mixed component refrigerant is cooled within the first heat exchange area by heat exchange with the first mixed component refrigerant.  
   
   
       59 . The method of  claim 48 , wherein the second mixed component refrigerant is condensed within the first heat exchange area by heat exchange with the first mixed component refrigerant.  
   
   
       60 . The method of  claim 48 , wherein the process stream consists essentially of natural gas.  
   
   
       61 . The method of  claim 48 , wherein the first mixed component refrigerant comprises ethane, propane, and isobutane.  
   
   
       62 . The method of  claim 48 , wherein the first mixed component refrigerant comprises ethane and propane.  
   
   
       63 . The method of  claim 48 , wherein the second mixed component refrigerant comprises methane, ethane and nitrogen.  
   
   
       64 . A method for cooling a process stream of natural gas, comprising: 
 placing a mixed component refrigerant stream in heat exchange with a process stream, the refrigerant stream comprising liquid refrigerant; and    discontinuing the heat exchange before the liquid refrigerant stream is completely vaporized.    
   
   
       65 . A method for liquefying a natural gas stream, comprising: 
 placing a mixed component refrigerant in a heat exchange area with a process stream;    separating the mixed component refrigerant at one or more pressure levels to produce a refrigerant vapor and a refrigerant liquid;    passing at least the refrigerant liquid to the heat exchange area; and    partially evaporating the refrigerant liquid within the heat exchange area to retain a liquid phase.    
   
   
       66 . A method for liquefying a natural gas stream, comprising: 
 placing a mixed component refrigerant in a heat exchange area with a process stream;    withdrawing two or more side streams of the mixed component refrigerant from the heat exchange area;    separating the side streams of mixed component refrigerant at one or more pressure levels to produce refrigerant vapors and refrigerant liquids;    passing at least the refrigerant liquids to the heat exchange area; and    partially evaporating the refrigerant liquids within the heat exchange area to retain a liquid phase.

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