Process for the treatment of a hydrocarbon feed containing hydrogen and hydrocarbons

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, comprising the following steps: separating the hydrocarbon feed into a gaseous phase and a liquid phase containing hydrocarbons; cooling the liquid phase obtained from step a) to a temperature of 45° C. or less using a cooling device; carrying out a first recontacting step on the cooled liquid phase with the gaseous phase in a counter-current column in order to recover a first gaseous effluent which is rich in hydrogen and a first liquid hydrocarbon effluent; in which, before the cooling step b), the liquid phase obtained from step a) is pre-cooled by exchange of heat in an exchanger supplied with the first gaseous effluent and/or the first liquid hydrocarbon effluent obtained from step c).

1 . A process for the treatment of a hydrocarbon feed containing hydrogen and hydrocarbons including C 1  to C 4  hydrocarbons, comprising the following steps:
 a) separating the hydrocarbon feed into a gaseous phase ( 6 ) and a liquid phase ( 4 ) containing hydrocarbons;   b) cooling the liquid phase ( 4 ) obtained from step a) to a temperature of 45° C. or less using a cooling device ( 15 );   c) carrying out a first recontacting step on the cooled liquid phase ( 4 ) with the gaseous phase ( 6 ) in a counter-current column ( 16 ) in order to recover a first gaseous effluent ( 17 ) which is rich in hydrogen and a first liquid hydrocarbon effluent ( 18 );   d) carrying out a second recontacting step on the first liquid hydrocarbon effluent ( 18 ) with a recycle gas ( 21 ) and separating a second gaseous effluent ( 24 ) which is enriched in C 1  and C 2  hydrocarbons and a second liquid hydrocarbon effluent ( 27 );   e) fractionating the second liquid hydrocarbon effluent ( 27 ) obtained from step d) in a fractionation column ( 28 ) in a manner such as to separate a gaseous overhead fraction ( 30 ) and a liquid bottom fraction ( 29 ) containing hydrocarbons containing more than 4 carbon atoms;   f) condensing the gaseous overhead fraction ( 30 ) obtained from step e) and separating a liquid phase ( 33 ) containing mainly C 3  and C 4  hydrocarbons and a gaseous phase ( 21 ) which is recycled to step d),   in which, before the cooling step b), the liquid phase obtained from step a) is pre-cooled by exchange of heat in an exchanger ( 11 ) supplied with the first gaseous effluent ( 17 ) and/or the first liquid hydrocarbon effluent ( 18 ) obtained from step c).   
     
     
         2 . The process according to  claim 1  in which, before the cooling step b), the liquid phase ( 4 ) obtained from step a) undergoes an exchange of heat in an exchanger ( 11 ) supplied with the first gaseous effluent ( 17 ) and in which the gaseous phase ( 6 ) obtained from step a) undergoes an exchange of heat in an exchanger ( 13 ) supplied with the first liquid hydrocarbon effluent ( 18 ). 
     
     
         3 . The process according to  claim 1  in which, before the cooling step b), the liquid phase ( 4 ) obtained from step a) undergoes an exchange of heat in an exchanger ( 13 ) supplied with the first gaseous effluent ( 18 ) and in which the gaseous phase ( 6 ) obtained from step a) undergoes an exchange of heat in an exchanger ( 13 ) supplied with the first liquid hydrocarbon effluent ( 17 ). 
     
     
         4 . The process according to  claim 1 , in which the liquid phase ( 4 ) obtained from step a) is cooled to a temperature of 0° C. or less using a cooling device ( 15 ). 
     
     
         5 . The process according to  claim 2 , in which the gaseous phase obtained from step a) is cooled to a temperature of 0° C. or less using a cooling device, it being understood that said step for cooling the gaseous phase is carried out after the heat exchange step in accordance with  claim 2 . 
     
     
         6 . The process according to  claim 1 , in which part or all of the second gaseous effluent ( 24 ) enriched in C 1  and C 2  hydrocarbons is recycled upstream of the first recontacting step. 
     
     
         7 . The process according to  claim 6 , in which the second gaseous effluent ( 24 ) is recycled as a mixture with the gaseous phase ( 6 ) obtained from step a). 
     
     
         8 . The process according to  claim 1 , in which the separation carried out in step d) is carried out with the aid of a separating drum. 
     
     
         9 . The process according to  claim 1 , in which the first recontacting step is carried out at a temperature in the range −20° C. to 55° C. 
     
     
         10 . The process according to  claim 1 , in which the first recontacting step is carried out at a pressure in the range 1.6 to 4 MPa. 
     
     
         11 . The process according to  claim 1 , in which the second recontacting step is carried out at a temperature in the range 10° C. to 55° C. 
     
     
         12 . The process according to  claim 1 , in which the column ( 16 ) comprises in the range 5 to 15 theoretical plates. 
     
     
         13 . The process according to  claim 1 , in which the hydrocarbon feed is an effluent from a catalytic reforming unit.