Device and method for cryogenically seperating a gas mixture

Abstract

The invention relates to a device for separating gas by means of cryogenic distillation, comprising a system of columns ( 13, 15 ), means for sending gas which is to be separated to a column belonging to said column system, means for drawing off at least one product ( 31,35 ) of the column system and means for sending gas from the device ( 23 ) into a turbine ( 11 ) with bearings wherein the bearings of said turbine are antifriction bearings.

1 - 12 . (canceled)  
   
   
       13 : A unit for separating gas by cryogenic distillation, comprising a system of columns, means for sending a gas to be separated to one column of the column system, means for withdrawing at least one product from the column system, means for sending a gas of the unit, possibly at least one portion of the gas mixture to be separated, into a turbine with bearings, and means for sending at least one portion of the gas expanded in the turbine to one column of the column system if the expanded gas constitutes at least one portion of the gas mixture to be separated, characterized in that the bearings of the turbine are rolling bearings.  
   
   
       14 : The unit as claimed in  claim 13 , in which the turbine has unoiled bearings.  
   
   
       15 : The unit as claimed in  claim 14 , in which the turbine has unlubricated bearings.  
   
   
       16 : The unit as claimed in  claim 13 , in which the gas to be separated contains oxygen and/or nitrogen and/or hydrogen and/or methane and/or carbon monoxide as main components.  
   
   
       17 : The unit as claimed in  claim 16 , in which the expanded gas is air, nitrogen or hydrogen.  
   
   
       18 : The unit as claimed in  claim 13 , in which the turbine is installed at least one meter above the floor, preferably at least two meters above the floor or even at least five meters above the floor.  
   
   
       19 : The unit as claimed in  claim 13 , in which the turbine is braked by a brake booster, possibly of the centrifugal type, placed on the same shaft as the turbine, all the bearings of this common shaft being unlubricated.  
   
   
       20 : The unit as claimed in  claim 19 , in which all the bearings of the common shaft are of the rolling bearing type.  
   
   
       21 : The unit as claimed in  claim 13 , in which the turbine is braked by a brake generator whose bearings are unlubricated.  
   
   
       22 : The unit as claimed in  claim 21 , in which the bearings of the brake generator are of the magnetic type.  
   
   
       23 : A method of separating a gas mixture by cryogenic distillation, in which a gas mixture to be separated is sent to a column of a column system, at least one product is withdrawn from the column system, at least one portion of a gas of the unit, possibly at least one portion of the gas mixture to be separated, is sent into a turbine with bearings, characterized in that the bearings of the turbine are rolling bearings.  
   
   
       24 : The method as claimed in  claim 23 , in which the turbine is braked by a brake generator whose bearings are unlubricated and the brake generator is driven at the same speed as the turbine.