Process for treating a hydrocarbon feed

Abstract

The present invention concerns a process for the treatment of a hydrocarbon feed containing hydrogen and hydrocarbons including C 1 to C 4 hydrocarbons. The process employs two steps for recontacting gaseous and liquid phases and in which at least one of the recontacting steps is carried out in a column ( 30, 40 ) in which the gaseous and liquid streams are brought into counter-current contact.

1 . A process for the treatment of a hydrocarbon feed containing hydrogen and hydrocarbons including C 1  to C 4  hydrocarbons, in which:
 a) the hydrocarbon feed is separated into a gaseous phase ( 6 ) and a liquid phase ( 4 ) containing hydrocarbons;   b) a first recontacting step is carried out by bringing the liquid phase into contact with a gaseous phase ( 8 ) obtained from step c) at a temperature in the range −20° C. to 60° C., then the recontacting mixture is separated into a first gaseous effluent ( 12 ) which is rich in hydrogen and a first liquid hydrocarbon effluent ( 13 );   c) a second recontacting step is carried out by bringing the first liquid hydrocarbon effluent ( 13 ) into contact with the gaseous phase ( 6 ) obtained from step a) and a recycle gas ( 14 ) obtained from step f) at a temperature in the range −20° C. to 60° C., then the recontacting mixture is separated into a second gaseous effluent ( 17 ) and a second liquid hydrocarbon effluent ( 18 );   d) the second gaseous effluent ( 17 ) is compressed and said second gaseous effluent is sent to step b) as the gaseous phase ( 8 );   e) the second liquid hydrocarbon effluent ( 18 ) obtained from step d) is fractionated in a fractionation column ( 19 ) in a manner such as to separate a gaseous overhead fraction ( 21 ) and a liquid bottom fraction ( 20 ) containing hydrocarbons containing more than 4 carbon atoms;   f) the gaseous overhead fraction ( 21 ) obtained from step e) is condensed and a liquid phase ( 24 ) containing mainly C 3  and C 4  hydrocarbons and a gaseous phase ( 14 ) are separated and recycled to step c),   
       in which at least step b) or step c) is carried out in a column ( 30 ,  40 ) in which the gaseous and liquid streams are brought into counter-current contact. 
     
     
         2 . The process as claimed in  claim 1 , in which step b) is carried out in a recontacting column ( 40 ) in which the liquid phase is brought into counter-current contact with the gaseous phase and in which step c) comprises in-line contact and a separation which is carried out using a separator drum. 
     
     
         3 . The process as claimed in  claim 1 , in which step c) is carried out in a recontacting column ( 30 ) in which the first liquid hydrocarbon effluent is brought into counter-current contact with the gaseous phase obtained from step a) and the recycle gas obtained from step f) and in which step b) comprises in-line contact and a separation which is carried out using a separator drum. 
     
     
         4 . The process as claimed in  claim 1 , in which steps b) and c) are carried out in a column in which the gaseous and liquid streams are brought into counter-current contact. 
     
     
         5 . The process as claimed in  claim 1 , in which in step b), contact is carried out at a pressure in the range 1.5 to 4.5 MPa. 
     
     
         6 . The process as claimed in  claim 1 , in which in step c), contact is carried out at a pressure in the range 0.8 to 3 MPa. 
     
     
         7 . The process as claimed in  claim 1 , in which step b) is carried out at a temperature in the range −10° C. to 10° C. 
     
     
         8 . The process as claimed in  claim 1 , in which step c) is carried out at a temperature in the range 20° C. to 50° C.