Method and system for removing impurities from hydrocarbon oils via lewis acid complexation

Abstract

A method is provided for purifying a hydrocarbon oil comprising a quantity of impurities. A Lewis acid solution comprising a Lewis acid and an aprotic solvent is added to the hydrocarbon oil having the plurality of impurities, e.g. sulfur, vanadium, and nickel impurities, to form a mixture. Complexes are formed between the Lewis acid of the Lewis acid solution and a respective one of the impurities in the mixture. The mixture is separated into a first layer that comprises a purified fraction of the hydrocarbon oil and a second layer comprising the complexes dissolved in the aprotic solvent.

1 . A method for purifying a hydrocarbon oil comprising a quantity of impurities, the method comprising:
 (a) adding a Lewis acid solution comprising a Lewis acid and an aprotic solvent to the hydrocarbon oil to form a mixture;   (b) forming complexes between the Lewis acid of the Lewis acid solution and respective ones of the impurities of the hydrocarbon oil in the mixture;   (c) separating the mixture into a first layer comprising a purified fraction of the hydrocarbon oil and a second layer comprising the complexes and the aprotic solvent; and   (d) recovering the first layer comprising the purified fraction of the hydrocarbon oil.   
   
   
       2 . The method of  claim 1 , wherein the impurities comprise at least one of sulfur, nickel, or vanadium. 
   
   
       3 . The method of  claim 1 , wherein a stoichiometric excess of the Lewis acid is provided relative to the impurities in the hydrocarbon oil. 
   
   
       4 . The method of  claim 1 , further comprising, after said recovering, repeating (a) through (d) for the first layer comprising the purified fraction of the hydrocarbon oil to obtain a second purified fraction of the hydrocarbon oil. 
   
   
       5 . The method of  claim 1 , further comprising, after said recovering, recapturing the Lewis acid by adding an acid to the second layer comprising the complexes. 
   
   
       6 . The method of  claim 1 , further comprising mixing the hydrocarbon oil with a solvent to form a fuel-solvent mixture prior to said forming complexes. 
   
   
       7 . The method of  claim 1 , wherein the Lewis acid comprises a hard Pearson Lewis acid. 
   
   
       8 . The method of  claim 7 , wherein the Lewis acid comprises at least one of AlCl 3 , GaCl 3 , FeCl 3 , or combinations thereof. 
   
   
       9 . The method of  claim 1 , wherein the impurities comprise at least one of thiophenes or derivatives thereof. 
   
   
       10 . The method of  claim 9 , wherein the impurities comprise at least one of benzothiophenes, dibenzothiophenes, phenanthiophenes, benzonathiophenes, thiophene sulfides, or derivatives thereof. 
   
   
       11 . The method of  claim 1 , wherein the hydrocarbon oil comprises at least one of a heavy fuel oil and a liquid oil, and wherein the liquid oil is obtained from at least one of bitumen, petroleum, oil shale, coal, or synthetic crude oil. 
   
   
       12 . The method of  claim 1 , wherein the aprotic solvent comprises at least one of acetonitrile, nitromethane, 1,2-dichloroethane, or combinations thereof. 
   
   
       13 . The method of  claim 1 , further comprising:
 prior to said adding (a), adding an amount of the fuel solvent to an amount of the hydrocarbon oil to form a mixture;   centrifuging the mixture to form a precipitate in the mixture and a supernatant comprising a pre-treated hydrocarbon oil; and   transferring the pre-treated hydrocarbon oil for use in said adding (a).   
   
   
       14 . A method for purifying a hydrocarbon oil comprising a quantity of sulfur impurities, the method comprising:
 (a) adding a Lewis acid solution comprising a Lewis acid and an aprotic solvent to the hydrocarbon oil to form a mixture;   (b) forming complexes between the Lewis acid of the Lewis acid solution and respective ones of the sulfur impurities of the hydrocarbon oil in the mixture;   (c) separating the mixture into a first layer comprising a purified fraction of the hydrocarbon oil and a second layer comprising the complexes and the aprotic solvent; and   (d) recovering the first layer comprising the purified fraction of the hydrocarbon oil.   
   
   
       15 . A system for purifying a hydrocarbon oil comprising a quantity of impurities comprising:
 a first vessel;   a hydrocarbon oil source for delivering an amount of the hydrocarbon oil comprising a quantity of impurities to the first vessel;   a Lewis acid source for delivering an amount of a Lewis acid and an aprotic solvent, if present, to the first vessel;   an aprotic solvent source for delivering an amount of the aprotic solvent to at least one of the first vessel or the Lewis acid source;   a mixer to mix the Lewis acid and the hydrocarbon oil to a degree effective to form a mixture comprising complexes between the Lewis acid and respective ones of the impurities in the hydrocarbon oil in the first vessel;   a separating device to separate the mixture into a first layer comprising a purified fraction of the hydrocarbon oil and a second layer comprising the complexes and the aprotic solvent in at least one of the first vessel or a second vessel; and   a recovering device to recover the first layer comprising the purified fraction of the hydrocarbon oil.   
   
   
       16 . The system of  claim 15 , wherein the impurities comprise at least one of sulfur, nickel, or vanadium. 
   
   
       17 . The system of  claim 15 , wherein an amount of the Lewis acid is in a stoichiometric excess of the Lewis acid relative to the impurities in the hydrocarbon oil. 
   
   
       18 . The system of  claim 17 , wherein the Lewis acid comprises a hard Pearson Lewis acid. 
   
   
       19 . The system of  claim 18 , wherein the Lewis acid comprises at least one of AlCl 3 , GaCl 3 , FeCl 3 , or mixtures thereof. 
   
   
       20 . The system of  claim 15 , wherein the impurities comprise thiophenes and derivatives thereof. 
   
   
       21 . The system of  claim 20 , wherein the impurities comprise at least one of benzothiophenes, dibenzothiophenes, phenanthiophenes, benzonathiophenes, thiophene sulfides, or derivatives thereof. 
   
   
       22 . The system of  claim 15 , wherein the hydrocarbon oil comprises at least one of a heavy fuel oil and a liquid oil, and wherein the liquid oil is obtained from at least one of bitumen, petroleum, oil shale, coal, or synthetic crude oil. 
   
   
       23 . The system of  claim 15 , wherein the aprotic solvent comprises at least one of acetonitrile, nitromethane, 1,2-dichloroethane, or combinations thereof.