Method and apparatus for liquefying a hydrocarbon stream

Abstract

The present invention provides a method of liquefying a hydrocarbon stream such as natural gas, the method at least comprising the steps of: (a) providing a hydrocarbon stream ( 10 ) at a first location ( 2 ), wherein the first location is situated onshore; (b) treating the hydrocarbon stream ( 10 ) in the first location ( 2 ) thereby obtaining a treated hydrocarbon stream ( 20 ); (c) transporting the treated hydrocarbon stream ( 20 ) via a pipeline ( 4 ) over a distance of at least 2 km to a second location ( 3 ), wherein the second location is situated off-shore; (d), liquefying the treated, hydrocarbon stream ( 20 ) at the second location ( 3 ) thereby obtaining liquefied hydrocarbon product ( 50 ) at atmospheric pressure.

1 . A method of liquefying a hydrocarbon stream, the method at least comprising the steps of:
 (a) providing a hydrocarbon stream at a first location, wherein the first location is situated onshore;   (b) treating the hydrocarbon stream in the first location thereby obtaining a treated hydrocarbon stream;   (c) transporting the treated hydrocarbon stream via a pipeline over a distance of at least 2 km to a second location, wherein the second location is situated off-shore; and   (d) liquefying the treated hydrocarbon stream at the second location thereby obtaining liquefied hydrocarbon product at atmospheric pressure.   
   
   
       2 . The method according to  claim 1 , wherein the treating in step (b) at least comprises removal of CO 2 . 
   
   
       3 . The method according to  claim 2 , wherein no CO 2  removal takes place at the second location. 
   
   
       4 . The method according to  claim 1 , wherein the treating in step (b) at least comprises removal of H 2 O. 
   
   
       5 . The method according to  claim 1 , wherein the treated hydrocarbon stream is compressed before transporting in step (c). 
   
   
       6 . The method according to  claim 1 , wherein the treated hydrocarbon stream is transported in a state being substantially above the critical point. 
   
   
       7 . The method according to  claim 1 , wherein during transporting the treated hydrocarbon stream is cooled by heat exchanging against the ambient. 
   
   
       8 . The method according to  claim 7 , wherein the treated hydrocarbon stream is cooled to a temperature <10° C. before it reaches the second location. 
   
   
       9 . The method according to  claim 1 , wherein the liquefied hydrocarbon product is transported and regasified. 
   
   
       10 . The method according to  claim 1 , wherein in step (d) a refrigerant is used, which refrigerant is produced at a different location than the second location and supplied to the second location via a pipeline. 
   
   
       11 . An apparatus for liquefying a hydrocarbon stream, the apparatus at least comprising:
 one or more treating units at a first location for obtaining a treated hydrocarbon stream, wherein the first location is situated onshore;   at least one liquefaction plant at a second location for producing a liquefied hydrocarbon product at atmospheric pressure, wherein the second location is situated off-shore;   a pipeline for transporting the treated hydrocarbon stream to the second location over a distance of at least 2 km.   
   
   
       12 . The apparatus according to  claim 11 , wherein one of the treating units at the first location is adapted for the removal of CO 2 . 
   
   
       13 . The apparatus according to  claim 11 , wherein no CO 2  removal from the treated hydrocarbon stream takes place at the second location. 
   
   
       14 . The apparatus according to  claim 11 , wherein one of the treating units at the first location is adapted for the removal of H 2 O. 
   
   
       15 . The apparatus according to  claim 11 , the apparatus further comprising a compressor for compressing the treated hydrocarbon stream at the first location. 
   
   
       16 . The apparatus according to  claim 11 , wherein the pipeline is substantially not thermally insulated. 
   
   
       17 . The method according to  claim 1 , wherein the treating in step (b) at least comprises removal of CO 2  such that the treated hydrocarbon stream comprises less than 500 ppm CO 2 . 
   
   
       18 . The method according to  claim 1 , wherein the treating in step (b) at least comprises removal of H 2 O such that the treated hydrocarbon stream comprises less than 100 ppm H 2 O. 
   
   
       19 . The method according to  claim 1 , wherein the treated hydrocarbon stream is compressed before transporting in step (c) to a pressure above 50 bar. 
   
   
       20 . The method according to  claim 7 , wherein the treated hydrocarbon stream is cooled to a temperature <0° C. before it reaches the second location.