Lng plant including an axial compressor and a centrifugal compressor

Abstract

The LNG plant comprises a compression train and a further compression. The compression train ( 100 ) comprises comprising an engine and a compressor driven by the engine; the compressor is an axial compressor and comprises a first set of axial compression stages and a second set of axial compression stages arranged downstream the first set of axial compression stages; at least the first set and the second set of axial compression stages are housed inside one case. The further compression train comprises a further engine and a further compressor driven by the further engine; the further compressor is a centrifugal compressor and comprises a first set of impellers and a second set of impellers arranged downstream or upstream the first set of impellers.

What we claim is: 
     
         1 . An LNG plant comprising a compression train;
 wherein the compression train comprises an engine and a compressor driven by the engine; wherein the compressor is an axial compressor and comprises a first set of axial compression stages and a second set of axial compression stages arranged downstream the first set of axial compression stages;   at least the first set and the second set of axial compression stages being housed inside one case;   the compressor having:
 one main inlet arranged upstream the first set of axial compression stages, 
 one main outlet arranged downstream the second set of axial compression stages, and 
 at least one auxiliary inlet and/or at least one auxiliary outlet arranged downstream the first set of axial compression stages and upstream the second set of axial compression stages, 
   wherein the compressor is configured so that a fluid entering the compressor through the auxiliary inlet is redirected from a substantially radial direction to a substantially axial direction and/or a fluid exiting the compressor through the auxiliary outlet is redirected from a substantially axial direction to a substantially radial direction;   wherein the LNG plant further comprises a further compression train, wherein the further compression train comprises a further engine and a further compressor driven by the further engine; wherein the further compressor is a centrifugal compressor and comprises a first set of impellers and a second set of impellers arranged downstream or upstream the first set of impellers;   the impellers of the first set being centrifugal and unshrouded;   the impellers of the second set being centrifugal and shrouded;   at least the impellers of the first set and of the second set being housed inside one case; and   the impellers of the first set and of the second set being coupled to each other through mechanical connections.   
     
     
         2 . The LNG plant of  claim 1 , wherein said fluid is redirected by an intermediate path extending from an external side of the auxiliary inlet/outlet to an internal side of the auxiliary inlet/outlet. 
     
     
         3 . The LNG plant of  claim 1 , wherein the engine is an electric motor or a steam turbine or a gas turbine. 
     
     
         4 . The LNG plant of  claim 1 , wherein the engine and the compressor are connected directly or through a gear train. 
     
     
         5 . The LNG plant of  claim 1 , wherein said compression train is a first compression train and is arranged to compress propane, wherein said further compression train is a second compression train and is arranged to compress methane, comprising further a third compression train arranged to compress ethylene or ethane; the first compression train, the second compression train and the third compression train cooperating to liquefy a flow of gaseous natural gas into a flow of liquid natural gas. 
     
     
         6 . The LNG plant of  claim 1 , wherein said compression train is a first compression train and is arranged to compress propane, wherein said further compression train is a second compression train and is arranged to compress ethylene or ethane, comprising further a third compression train arranged to compress methane; the first compression train, the second compression train and the third compression train cooperating to liquefy a flow of gaseous natural gas into a flow of liquid natural gas. 
     
     
         7 . The LNG plant of  claim 5 , wherein the third compression train comprises at least one centrifugal compressor. 
     
     
         8 . The LNG plant of  claim 7 , wherein said at least one centrifugal compressor of said fourth train comprises a first set of impellers and a second set of impellers arranged downstream or upstream the first set of impellers;
 the impellers of the first set being centrifugal and unshrouded;   the impellers of the second set being centrifugal and shrouded;   at least the impellers of the first set and of the second set being housed inside one case; and   the impellers of the first set and of the second set being coupled to each other through mechanical connections.   
     
     
         9 . The LNG plant of  claim 1 , wherein said compression train is a first compression train and is arranged to compress propane, wherein said further compression train is a second compression train and is arranged to compress mixed refrigerant; the first compression train and the second compression train cooperating to liquefy a flow of gaseous natural gas into a flow of liquid natural gas. 
     
     
         10 . The LNG plant of  claim 1 , wherein said compression train is a first compression train and is arranged to compress propane, wherein said further compression train is a second compression train and is arranged to compress mixed refrigerant, comprising further a fourth compression train arranged to compress nitrogen; the first compression train, the second compression train and the fourth compression train cooperating to liquefy a flow of natural gas. 
     
     
         11 . The LNG plant of  claim 10 , wherein the fourth compression train comprises at least one centrifugal compressor. 
     
     
         12 . The LNG plant of  claim 11 , wherein said at least one centrifugal compressor of said fourth train comprises a first set of impellers and a second set of impellers arranged downstream or upstream the first set of impellers;
 the impellers of the first set being centrifugal and unshrouded;   the impellers of the second set being centrifugal and shrouded;   at least the impellers of the first set and of the second set being housed inside one case; and   the impellers of the first set and of the second set being coupled to each other through mechanical connections.