Oxidative desulfurization of fuel oil

Abstract

A method for purifying a sulfur-containing fuel oil comprising (a) contacting in a first reaction mixture the sulfur-containing fuel oil with an exogenous binary catalyst, hydrogen peroxide, and a water-soluble acid at a temperature in a range of from about 25° C. to about 150° C. to provide a first oxidized mixture; and (b) separating at least one oxidized sulfur compound from the first oxidized mixture to provide a purified fuel oil. The first reaction mixture may further comprise a phase transfer catalyst. Furthermore, the sulfur-containing fuel oil may be deasphalted prior to contacting with the catalyst, hydrogen peroxide, and the water-soluble acid.

1 . A method for purifying a sulfur-containing fuel oil, the method comprising:
 (a) contacting in a first reaction mixture the sulfur-containing fuel oil with an exogenous binary catalyst, hydrogen peroxide and a water-soluble acid, at a temperature in a range of from about 25° C. to about 120° C. to provide a first oxidized mixture; and   (b) separating at least one oxidized sulfur compound from the first oxidized mixture to provide a purified fuel oil.   
   
   
       2 . The method according to  claim 1 , wherein the sulfur-containing fuel oil comprises less than 5 weight percent sulfur. 
   
   
       3 . The method according to  claim 1 , wherein the sulfur-containing fuel oil comprises less than 3 weight percent sulfur. 
   
   
       4 . The method according to  claim 1 , wherein the exogenous binary catalyst comprises a first component selected from the group consisting of phosphate salts, and oxides, acids and salts of molybdenum, tungsten, manganese, and combinations thereof, and a second component selected from the group consisting of oxides and salts of cerium, iron, vanadium, titanium, manganese, cobalt, nickel, copper and combinations thereof. 
   
   
       5 . The method according to  claim 4 , wherein the first component comprises an oxide or a salt of manganese. 
   
   
       6 . The method according to  claim 4 , wherein the second component comprises an oxide or a salt of cobalt. 
   
   
       7 . The method according to  claim 4 , wherein the second component comprises an oxide or a salt of cerium. 
   
   
       8 . The method according to  claim 4 , wherein the second component comprises an oxide or a salt of iron. 
   
   
       9 . The method according to  claim 4 , wherein the exogenous binary catalyst comprises oxides, acids or salts of molybdenum as the first component and oxides or salts of cerium as the second component. 
   
   
       10 . The method according to  claim 4 , wherein the exogenous binary catalyst comprises oxides or salts of manganese as the first component and oxides or salts of iron, cobalt, or nickel as the second component. 
   
   
       11 . The method according to  claim 4 , wherein the exogenous binary catalyst comprises phosphate salts as the first component and oxides or salts of iron, cobalt, or nickel as the second component. 
   
   
       12 . The method according to  claim 4 , wherein the first component comprises an oxide, an acid or a salt of molybdenum. 
   
   
       13 . The method according to  claim 12 , wherein the first component comprises a molybdenum isopolyacid or its salt. 
   
   
       14 . The method according to  claim 1 , wherein the sulfur-containing fuel oil is deasphalted prior to contacting the sulfur-containing fuel oil with the binary catalyst, hydrogen peroxide and the water-soluble acid by contacting the sulfur-containing fuel with an inert diluent. 
   
   
       15 . The method according to  claim 1 , wherein the water-soluble acid is selected from the group consisting of formic acid, acetic acid, propionic acid, butyric acid, sulfuric acid, phosphoric acid, and mixtures of two or more of the foregoing acids. 
   
   
       16 . The method according to  claim 1 , wherein the separating is carried out using solid-liquid extraction. 
   
   
       17 . The method according to  claim 1 , wherein the separating is carried out using liquid-liquid extraction. 
   
   
       18 . The method according to  claim 1 , wherein the sulfur-containing fuel oil comprises benzothiophene, dibenzothiophene, alkyl substituted benzothiophenes, and alkyl substituted dibenzothiophenes. 
   
   
       19 . The method according to  claim 1 , further comprising a step of recovering the binary catalyst. 
   
   
       20 . The method according to  claim 1 , wherein the first reaction mixture further comprises a phase transfer catalyst. 
   
   
       21 . The method according to  claim 20 , wherein the phase transfer catalyst comprises a quaternary ammonium salt or a quaternary phosphonium salt. 
   
   
       22 . A method for purifying a sulfur-containing fuel oil, the method comprising:
 (a) contacting in a first reaction mixture the sulfur-containing fuel oil with a hydrocarbon diluent, an exogenous binary catalyst, hydrogen peroxide, and a water-soluble acid at a temperature in a range of from about 25° C. to about 110° C. to provide a first oxidized mixture;   (b) separating at least one oxidized sulfur compound from the first oxidized mixture; and   (c) recovering the hydrocarbon diluent to provide a purified fuel oil.   
   
   
       23 . The method according to  claim 22 , wherein the exogenous binary catalyst comprises a first component selected from the group consisting of phosphate salts, and oxides, acids and salts of molybdenum, tungsten, manganese, and combinations thereof, and a second component selected from the group consisting of oxides and salts of cerium, iron, vanadium, titanium, manganese, cobalt, nickel, copper and combinations thereof. 
   
   
       24 . A method for purifying a sulfur-containing fuel oil, the method comprising:
 (a) contacting a sulfur-containing fuel oil comprising benzothiophene, dibenzothiophene, alkyl substituted benzothiophenes, and alkyl substituted dibenzothiophenes with petroleum-ether, a exogenous binary catalyst, and oxygen at a temperature in a range of from about 25° C. to about 120° C., and at a pressure in a range of from about 1 atmosphere to about 150 atmospheres to provide a first oxidized mixture comprising sulfoxides and sulfones of benzothiophene, dibenzothiophene, alkyl substituted benzothiophenes, and alkyl substituted dibenzothiophenes;   (b) separating at least one oxidized sulfur compound from the first oxidized mixture; and   (c) recovering petroleum-ether to provide a purified fuel oil.   
   
   
       25 . The method according to  claim 24 , wherein the exogenous binary catalyst a first component selected from the group consisting of phosphate salts, and oxides, acids and salts of molybdenum, tungsten, manganese, and combinations thereof, and a second component selected from the group consisting of oxides and salts of cerium, iron, vanadium, titanium, manganese, cobalt, nickel, copper and combinations thereof.