Method for Removing Sulfides from a Liquid Fossil Fuel

Abstract

The desulfurization of fossil fuels is provided by the combination of fossil fuels with an aqueous mixture of ozone or hydrogen peroxide and a Tetraoctylphosphonium salt phase transfer catalyst, and the mixture is then subjected to reactive mixing to form oxidize sulfur compounds in the fuel. The polar oxidized sulfones species are removed via another mixing step. The desulfurization device can be in the form of a portable device which provides for continuous mixing-assisted desulfurization for the removal of sulfur containing compounds from fossil fuels such as diesel fuel.

What is claimed is: 
     
         1 . A method for removing sulfides from a liquid fossil fuel, comprising:
 (a) combining a liquid fossil fuel with an oxidizer solution, a metal catalyst, and a phase transfer catalyst to form a multiphase reaction medium;   (b) reactive mixing and agitating the multiphase reaction medium via a mixer of a first mixing tank for a time sufficient to cause oxidation of sulfides in the fossil fuel to sulfones and to produce a plurality of bubble formations;   (c) separating an oil phase from an aqueous phase using a first cyclone, wherein the oil phase contains the fossil fuel and the sulfones;   (d) delivering the oil phase into a second mixing tank having a mixer;   (e) adding a plurality of adsorbents in the second mixing tank so as to absorb the sulfones by the adsorbents;   (f) separating the adsorbents from the oil phase to yield an organic phase that is substantially sulfone-free.   
     
     
         2 . The method in accordance with  claim 1 , wherein the adsorbents are activated clay. 
     
     
         3 . The method in accordance with  claim 1 , wherein the adsorbents are ion-impregnated activated carbon. 
     
     
         4 . The method in accordance with  claim 3 , wherein the ion-impregnated activated carbon is copper ion-impregnated activated carbons□ferric ion-impregnated activated carbons□nickel ion-impregnated activated carbons□ 
     
     
         5 . The method in accordance with  claim 1 , wherein the adsorbents are Aluminum oxide. 
     
     
         6 . The method in accordance with  claim 1 , wherein the adsorbents are Chitosan-coated bentonite. 
     
     
         7 . The method in accordance with  claim 1 , wherein a rotation rate of the mixer of the first mixing tank is 10,000 RPM. 
     
     
         8 . The method in accordance with  claim 1 , further comprising: recycling the aqueous solvent solution including the phase transfer catalyst, the oxidizer solution, and the metal catalyst after the step (b). 
     
     
         9 . The method in accordance with  claim 1 , wherein the adsorbents is separated from the oil phase by a centrifuge in the step (f). 
     
     
         10 . The method in accordance with  claim 1 , wherein the adsorbents is separated from the oil phase by a filter in the step (f). 
     
     
         11 . The method in accordance with  claim 1 , wherein the phase transfer catalyst is a quaternary ammonium salt. 
     
     
         12 . The method for removing sulfides in accordance with  claim 1 , wherein the oxidizer solution comprising of hydrogen peroxide, hydroperoxide, or ozone. 
     
     
         13 . The method in accordance with  claim 1 , wherein the mixing ratio of liquid fossil fuel and the oxidizer solution is about 1:1 to about 1:3. 
     
     
         14 . The method in accordance with  claim 1 , wherein the metal catalyst is selected from the group consisting of iron (II), iron (III), copper (I), copper (II), chromium (III), and chromium (VI) compounds, and molybdates, tungstates, and vanadates with the liquid fossil fuel and the oxidizer solution to form the multiphase reaction medium. 
     
     
         15 . The method in accordance with  claim 14 , wherein the metal catalyst is a phosphotungstic acid. 
     
     
         16 . The method in accordance with  claim 1 , wherein the liquid fossil fuel is a member selected from the group consisting of crude oil, shale oil, diesel fuel, gasoline, kerosene, liquefied petroleum gas, and petroleum residual-based fuel oils. 
     
     
         17 . The method in accordance with  claim 1 , wherein the liquid fossil fuel is diesel fuel or diesel fuel blend. 
     
     
         18 . A method for removing sulfides from a liquid fossil fuel, comprising:
 (a) combining a liquid fossil fuel with an oxidizer solution, a metal catalyst, and a phase transfer catalyst to form a multiphase reaction medium; and   (b) reactive mixing and agitating the multiphase reaction medium via a mixer of a first mixing tank for a time sufficient to cause oxidation of sulfides in the fossil fuel to sulfones and to produce a plurality of bubble formations comprising a substantial number of bubbles of less than 1 mm in diameter in the first mixing tank;   (c) separating an oil phase from an aqueous phase using a first cyclone;   (d) mixing and separating of an oil phase from a polar solvent phase via a mixer of a second mixing tank and producing a plurality of bubble formations comprising a substantial number of bubbles of less than 0.1 mm in diameter in the second mixing tank;   (e) recycling the aqueous solvent solution including the phase transfer catalyst , the oxidizer solution, and the metal catalyst; and   (f) separating the oil phase from the polar solvent phase using a second cyclone, and separating and collecting the sulfones to yield an organic phase that is substantially sulfone-free.   
     
     
         19 . The method in accordance with  claim 1 , wherein a rotation rate of the mixer of the first mixing tank is 10,000 RPM.