Station for reducing gas pressure and liquefying gas

Abstract

The invention relates to a station comprising an expansion turbine 12; means for recovering mechanical work (G) produced during the gas pressure reduction in the expansion turbine; a cooling system ( 6 ) comprising compression means (C 1, C 2, C 3 ), condensation means ( 14 ) for liquefying gas (G 11 ) using the cold provided by the cooling system, means for recovering heat produced by the compression means (C 1, C 2, C 3 ) of the cooling system and means ( 10 ) for heating the gas upstream of the expansion turbine that are associated with the heat-recovery means.

1 - 11 . (canceled) 
     
     
         12 . A station for reducing the pressure (PLD) of a gas and for liquefying the gas, comprising:
 an expansion turbine ( 12 );   means for recovering mechanical work (WM) produced during reduction of pressure of the gas;   a refrigeration system comprising compression means (C 1 , C 2 , C 3 );   condensation means ( 14 ) for liquefying the gas; and   means for recovering heat (Q) produced by the compression means (C 1 , C 2 , C 3 ; C) of the refrigeration system; the compression means associated with means ( 10 ;  110 ) for heating the gas upstream of the expansion turbine ( 12 ).   
     
     
         13 . The station according to claim  1 , further comprising a branch pipeline (G 9 ) downstream of the expansion turbine ( 12 ) for supplying the condensation means ( 14 ). 
     
     
         14 . The station according to claim  1 , wherein said station comprises a closed loop between the condensation means ( 14 ), the compression means (C 1 , C 2 , C 3 ; C) and the heating means ( 10 ) for the gas. 
     
     
         15 . The station according to claim  1 , wherein said station comprises a first closed loop between the compression means (C 1 , C 2 , C 3 ), the condensation means ( 14 ) and at least one intermediate heat exchanger ( 10 ); and a second closed loop, between the at least one intermediate heat exchanger ( 10 ) and the heating means ( 110 ) for the gas. 
     
     
         16 . The station according to  claim 15 , wherein the first closed loop comprises a first heat transfer fluid, and the second closed loop comprises a second heat transfer fluid different from said first heat transfer fluid. 
     
     
         17 . The station according to claim  1 , further comprising means for converting (G) mechanical work into electrical energy, said converting means associated with the means for recovering mechanical work (WM) produced during the reduction of the pressure of the gas. 
     
     
         18 . The station according to  claim 17 , wherein the converting means (G) comprises an electrical generator mechanically coupled to the means for recovering mechanical work (WM), and further comprising a motor (M) supplied with electrical energy by the electric generator for driving the compression means (C 1 , C 2 , C 3 ). 
     
     
         19 . The station according to claim  1 , wherein the means for recovering mechanical work (WM) produced during the reduction of the pressure of the gas is mechanically connected to the compression means (C 1 , C 2 , C 3 ; C). 
     
     
         20 . The station according to  claim 19 , further comprising an auxiliary motor (M) for driving the compression means (C 1 , C 2 , C 3 ). 
     
     
         21 . The station according to claim  1 , wherein the refrigeration system comprises a refrigerant selected from the group consisting of nitrogen, a mixture of hydrocarbons, and nitrogen and a mixture of hydrocarbons. 
     
     
         22 . The station according to claim  1 , further comprising compressors and/or radial flow expanders. 
     
     
         23 . The station according to claim  1 , further comprising means for treatment ( 8 ,  36 ) of the gas by at least one of adsorption, adsorption arranged upstream of the condensation means ( 14 ), and adsorption and absorption arranged upstream of the condensation means. 
     
     
         24 . The station according to claim  1 , wherein the gas comprises natural gas.