Process and device for desulphurizing hydrocarbons containing thiophene derivatives

Abstract

The invention relates to a selective desulphurisation method for thiophene derivatives contained in the hydrocarbons emitted from the distillation of crude oil, refined or not, consisting in oxidising the atoms of thiophene sulphur in sulphone in the presence of an oxidising agent and separating the sulphonated compounds from said hydrocarbons. This inventive method comprises at least one first stage involving the oxidation/absorption by heterogeneous catalysis of the sulphurous compounds in an organic environment, at a temperature of at least 40?C, at atmospheric pressure in the presence of an organic oxidiser from the family of peroxides and peracids, in the presence of a catalyst having a specific surface area greater than 100 m2/g and a porosity varying from 0.2 to 4 ml/g, and a second stage wherein the used catalyst is regenerated.

1 . Process for selectively desulfurizing the thiophenic derivatives contained in the hydrocarbons produced from the distillation of crude oil, refined or not, consisting of oxidizing the thiophenic sulfur atoms into sulfones in the presence of an oxidizing agent, and of separating the sulfonated compounds from said hydrocarbons, this process being characterized in that it includes at least a first step of oxidation/adsorption by heterogeneous catalysis of the sulfurous compounds, in organic medium, at a temperature of at least 40° C., in the presence of an organic oxidizer from the family of peroxides and peracids and in the presence of a catalyst having a specific surface area greater than 100 m 2 /g and a porosity varying from 0.2 to 4 ml/g, and a second step of regeneration of the used catalyst, the regeneration step always following the oxidation/adsorption step.  
   
   
       2 . Process according to  claim 1 , characterized in that the oxidation/adsorption and regeneration steps are carried out successively in the same reactor on the same catalyst.  
   
   
       3 . Process according to  claim 1 , characterized in that the oxidation/adsorption and regeneration steps are carried out simultaneously in reactors ( 1 ,  2 ) arranged in parallel and operating alternately for one and other steps.  
   
   
       4 . Process according to  claim 1 , characterized in that the oxidation/adsorption and regeneration steps are carried out in two moving-bed reactors ( 20   a ,  20   b ) connected to each other by the catalytic bed, one being used for the oxidation, the other for the regeneration.  
   
   
       5 . Process according to  claim 1 , characterized in that the oxidizing agent is selected from the group consisting of organic peroxides, organic hydroperoxides, and peracids.  
   
   
       6 . Process according to  claim 1 , characterized in that the catalyst includes a support selected from the group consisting of silicas, aluminas, zirconias, amorphous or crystalline aluminosilicates, aluminophosphates, mesoporous solids, activated carbon, clays, and their mixtures.  
   
   
       7 . Process according to  claim 6 , characterized in that the catalyst contains at least a metal selected from the group consisting of titanium, zirconium, vanadium, chromium, molybdenum, iron, manganese and tungsten, this metal being introduced into the matrix of the support or deposited in oxide form on the support.  
   
   
       8 . Process according to  claim 1 , characterized in that the catalyst contains from 0 to 30% by weight of metal in oxide form.  
   
   
       9 . Process according to  claim 1 , characterized in that the catalyst is comprised of at least a support selected from gamma-alumina, silica and silicic mesoporous solids and silicoaluminates.  
   
   
       10 . Process according to  claim 9 , characterized in that the supported catalyst is selected from catalysts containing tungsten on a support selected from silicas and aluminum oxides, alone or in mixture.  
   
   
       11 . Process according to  claim 1 , characterized in that the oxidizer/total sulfur mol ratio in the hydrocarbons varies from 2 to 20.  
   
   
       12 . Process according to  claim 1 , characterized in that the oxidizer is a compound with the general formula R 1 OOR 2 , in which R 1  and R 2  are selected identical or different from the group consisting of the hydrogen atom and the alkyl groups, linear or branched, having from 1 to 30 carbon atoms, while R 1  and R 2  cannot be hydrogen simultaneously.  
   
   
       13 . Process according to  claim 12 , characterized in that the oxidizer is selected from the group consisting of tert-butyl hydroperoxide and di-tert butyl peroxide.  
   
   
       14 . Process according to  claim 1 , characterized in that the oxidizer is a peracid of formula R 3 COOOH, in which R 3  is hydrogen or a linear or branched alkyl group having from 1 to 30 carbon atoms.  
   
   
       15 . Process according to  claim 14 , characterized in that the oxidizer is selected from the group consisting of peracetic acid, performic acid, and perbenzoic acid.  
   
   
       16 . Process according to  claim 1 , characterized in that the catalyst regeneration step consists of eliminating the formed deposits by washing or combustion.  
   
   
       17 . Process according to  claim 1 , wherein the hydrocarbons produced from the distillation of crude oil are selected from the group consisting of hydrotreated gasoils, kerosenes, and gasolines.  
   
   
       18 . Process according to  claim 8 , characterized in that the catalyst contains from 0 to 20% by weight of metal in oxide form.  
   
   
       19 . Process according to  claim 11 , characterized in that the oxidizer/total sulfur mol ratio in the hydrocarbons varies from 2 to 6.  
   
   
       20 . Process according to  claim 17 , wherein the hydrocarbons produced from the distillation of crude oil are gasolines produced from catalytic cracking.