Process for the desulfurization of olefinic gasolines by increasing the weight of sulfur-containing compounds with regeneration of the catalyst

Abstract

This invention relates to a process for the desulfurization of olefinic gasolines that employs a reaction for increasing the weight of sulfur-containing compounds by alkylation on the olefins of the feedstock, by means of an acidic catalyst, and that comprises a regeneration of the catalyst that can be carried out sequentially or continuously.

1 . Process for the desulfurization of a gasoline fraction that contains olefins, sulfur-containing compounds and optionally molecules that belong to the C3 and C4 fractions, comprising at least: 
 A first stage A for bringing said gasoline fraction into contact with an acidic catalyst that makes it possible to carry out an alkylation reaction between the olefins and the sulfur-containing compounds of said gasoline fraction and that produces sulfur-containing compounds that are increased in weight,    A second stage B for fractionation of the mixture that is obtained from the first stage that makes it possible to produce a light fraction whose sulfur content is reduced relative to the feedstock and a heavy fraction that concentrates the sulfur-containing compounds that are increased in weight,    A third stage C for regeneration of the catalyst that is used in stage A that has a duration of between one hour and 250 hours and that consists in bringing the catalyst into contact with a regeneration agent that contains at least one compound that is selected from the group that is formed by the oxidized compounds or the aromatic compounds.    
   
   
       2 . Process for the desulfurization of a gasoline fraction according to  claim 1 , in which the regeneration agent that is used in stage C is introduced in a mixture with the feedstock.  
   
   
       3 . Process for the desulfurization of a gasoline fraction according to  claim 1 , in which the molar ratio between the olefinic compounds and the aromatic compounds of the regeneration agent or of the mixture that results between the regeneration agent and the feedstock to be treated is between 0 and 1, preferably between 0 and 0.5, and even preferably between 0 and 0.25.  
   
   
       4 . A process for the desulfurization of a gasoline fraction according to  claim 1 , in which the acidic catalyst that is used is selected from among the ion exchange acid resins.  
   
   
       5 . A process for the desulfurization of a gasoline fraction according to  claim 4 , in which the acid resin has an acid capacity of more than 4.7 eq/kg and preferably more than 5.0 eq/kg.  
   
   
       6 . A process for the desulfurization of a gasoline fraction according to  claim 4 , in which the acid resin that is used has a mean particle size of less than 2 mm.  
   
   
       7 . A process for the desulfurization of a gasoline fraction according to  claim 1 , in which the catalyst contains the phosphoric acid that is mixed with silica, with a phosphoric acid content of more than 50% by weight.  
   
   
       8 . A process for the desulfurization of a gasoline fraction according to  claim 1 , in which the catalyst is an amorphous silica-alumina.  
   
   
       9 . A process for the desulfurization of a gasoline fraction according to  claim 1 , in which the catalyst is a zeolite that is selected from the group that consists of the Y, beta, ZSM-5, ZSM-3 and ZSM-20, ZSM-57, NU-88, NU-87, NU-86 and EU-1 zeolites.  
   
   
       10 . A process for the desulfurization of a gasoline fraction according to  claim 1 , in which the operating temperature of the stage A is between 30° C. and 300° C., the operating pressure of stage A is encompassed in 0.5 MPa and 6.0 MPa, and the VVH is between 0.1 h −1  and 10 h −1 .  
   
   
       11 . A process for the desulfurization of a gasoline fraction according to  claim 1  in which, when the catalyst that is used is an acid resin, the operating temperature of the reaction is between 30° C. and 180° C., and preferably between 40° C. and 170° C.  
   
   
       12 . A process for the desulfurization of a gasoline fraction according to  claim 1 , in which, when the catalyst that is used is the phosphoric acid that is mixed with silica, the operating temperature of the reaction is between 100° C. and 300° C., and preferably between 140° C. and 250° C.  
   
   
       13 . A process for the desulfurization of a gasoline fraction according to  claim 1 , in which, when the catalyst that is used is a zeolite, the operating temperature of the reaction is between 100° C. and 300° C., and preferably between 120° C. and 270° C.  
   
   
       14 . A process for the desulfurization of a gasoline fraction according to  claim 1 , in which, when the catalyst that is used is an acid resin, the temperature that is used in the regeneration stage is greater than or equal to the temperature of the reaction stage and less than 180° C.  
   
   
       15 . A process for the desulfurization of a gasoline fraction according to  claim 1 , in which, when the catalyst that is used is phosphoric acid or a zeolite, the temperature that is used in the regeneration stage is greater than or equal to the temperature of the reaction stage and less than 300° C.  
   
   
       16 . A process for the desulfurization of a gasoline fraction according to  claim 1 , in which, when the feedstock to be treated contains more than 20 ppm of nitrogen, and preferably more than 50 ppm of nitrogen, said feedstock is pretreated in a stage for extracting nitrogen-containing compounds.  
   
   
       17 . A process for the desulfurization of a gasoline fraction according to  claim 1 , in which, when the catalyst is an acid resin, it is used in the boiling-bed state.