Process for producing hydrocarbons with low sulphur and nitrogen contents

Abstract

A process for desulphurizing a gasoline feed comprising at least 150 ppm by weight of sulphur-containing compounds using a hydrodesulphurization catalyst is characterized in that said feed undergoes prior denitrogenation treatment under conditions such that the amount of nitrogen-containing compounds present in said feed when it is brought into contact with said hydrodesulphurization catalyst does not exceed 150 ppm by weight.

1 . A process for desulphurizing a gasoline feed comprising at least 150 ppm by weight of sulphur-containing compounds using a hydrodesulphurization catalyst, characterized in that said feed undergoes prior denitrogenation treatment under conditions such that the amount of nitrogen-containing compounds present in said feed when it is brought into contact with said hydrodesulphurization catalyst does not exceed 150 ppm by weight.  
     
     
         2 . A process according to  claim 1 , in which said denitrogenation treatment is carried out immediately prior to said contact.  
     
     
         3 . A process according to  claim 1 , in which at least one step selected from the group constituted by: 
 a) selective hydrogenation of the dienes contained in the feed;    b) transformation of light sulphur-containing compounds contained in the feed;    c) separation of said feed into at least two fractions including: 
 a light fraction containing a minor portion of the sulphur-containing compounds;  
 a heavy fraction containing a major portion of the sulphur-containing compounds;  
   is carried out between said denitrogenation treatment (step d)) and said contact with the hydrodesulphurization catalyst (step e) and possibly step f))    
     
     
         4 . A process according to  claim 3 , in which said contact is made with at least the heavy fraction from step c).  
     
     
         5 . A process according to  claim 2 , in which at least one step selected from the group constituted by: 
 a) selective hydrogenation of the dienes contained in the feed;    b) transformation of light sulphur-containing compounds contained in the feed;    c) separation of said feed into at least two fractions including: 
 a light fraction containing a minor portion of the sulphur-containing compounds;  
 a heavy fraction containing a major portion of the sulphur-containing compounds;  
   is carried out prior to said denitrogenation temperature (step d)).    
     
     
         6 . A process according to  claim 5 , in which contact with the hydrodesulphurization catalyst is made with at least the heavy fraction from step c).  
     
     
         7 . A process according to one of the preceding claims, in which said contact is made in at least two steps e) and f).  
     
     
         8 . A process according to one of the preceding claims, in which said hydrodesulphurization catalyst comprises at least one element from group VII of the periodic table.  
     
     
         9 . A process according to one of the preceding claims, in which said hydrodesulphurization catalyst comprises at least one element from group VIB of the periodic table.  
     
     
         10 . A process according to  claim 8  or  claim 9 , in which said catalyst comprises at least one element from group VIII of the periodic table selected from the group constituted by nickel and cobalt, and at least one group VIB element selected from the group constituted by molybdenum and tungsten.  
     
     
         11 . A process according to one of the preceding claims, in which said contact is made at a temperature in the range 250° C. to 350° C., a pressure in the range 1 to 3 MPa, an hourly space velocity in the range 1 h −1  to 10 h −1 , and a H 2 /HC ratio in the range 50 l/l to 500 l/l.  
     
     
         12 . Application of the process according to one of the preceding claims, to gasoline from catalytic cracking or from cokefaction of a heavy hydrocarbon feed or from steam cracking.