Composition Process And Apparatus To Remove Sulfur From Refined Crude Oil Fraction

Abstract

A ionic liquid composition to remove sulfur from refined crude oil fraction, comprising or consisting of two or more compounds having: —an imidazolium cation substituted by one or more straight or branched C 1 -C 6 alkyl group and —an anion selected from the group consisting of R 5 COO, CI., Br, [BF 4 ], [PF 6 ]—, [SbF 6 ]—, [R 6 SO 4 ], [OTs], [OMs], wherein R5 is C 1 -C 8 alkyl, Cs—Cs cycloalkyl, benzyl, C 2 -C 6 alkenyl, and R6 is C 1 -C 6 alkyl.

1 . An ionic liquid composition to remove sulfur from refined crude oil fraction, comprising two or more compounds having:
 an imidazolium cation substituted by one or more straight or branched C 1 -C 6  alkyl group, and   an anion selected from the group consisting of R 5 COO − , Cl − , Br − , [BF 4 ] − , [PF 6 ] − , [SbF 6 ] − , [R 6 SO 4 ] − , [OTs] − , [OMs] − , wherein R5 is C 1 -C 6  alkyl, C 3 -C 8  cycloalkyl, benzyl, C 2 -C 6  alkenyl, and R6 is C 1 -C 6  alkyl.   
     
     
         2 . The composition of  claim 1 , wherein the imidazolium cation is substituted in position 1 and 3 by a straight or branched C 1 -C 6  alkyl group, optionally is substituted in position 1 by butyl and in position 3 by methyl. 
     
     
         3 . The composition of  claim 1 , wherein the anion is selected from [BF 4 ] −  and [PF 6 ] − . 
     
     
         4 . The composition of  claim 1 , wherein the two or more compounds comprise:
 1-butyl-3-methyl imidazolium hexafluoro phosphate, and   1-butyl-3-methyl imidazolium tetrafluoroborate.   
     
     
         5 . The composition of  claim 1 , wherein the anion is selected from Cl − , [BF 4 ] −  and [PF 6 ] − . 
     
     
         6 . The composition of  claim 1 , comprising:
 1-butyl-3-methyl imidazolium hexafluoro phosphate,   1-butyl-3-methyl imidazolium tetrafluoroborate, and   1-butyl-3-methyl imidazolium chloride.   
     
     
         7 . The composition of  claim 6 , comprising:
 from 30 to 50% by volume of 1-butyl-3-methyl imidazolium hexafluoro phosphate,   from 20 to 30% by volume of 1-butyl-3-methyl imidazolium tetrafluoroborate,   from 25 to 35% by volume of 1-butyl-3-methyl imidazolium chloride,   
       with respect to the total volume of the composition. 
     
     
         8 . The composition of  claim 7 , comprising:
 from 35 to 44% by volume of 1-butyl-3-methyl imidazolium hexafluoro phosphate,   from 22 to 27% by volume of 1-butyl-3-methyl imidazolium tetrafluoroborate,   from 26 to 29% by volume of 1-butyl-3-methyl imidazolium chloride,   
       with respect to the total volume of the composition. 
     
     
         9 . The composition of  claim 6 , wherein the volume ratio between 1-butyl-3-methyl imidazolium hexafluoro phosphate, 1-butyl-3-methyl imidazolium tetrafluoroborate and 1-butyl-3-methyl imidazolium chloride is comprised between 1:0.63:0.74 and 1:0.61:0.66. 
     
     
         10 . The composition of  claim 1 , wherein the composition (i) does not comprise an oxidizing agent; and/or (ii) does not comprise a metal salt. 
     
     
         11 . The composition of  claim 1 , additionally comprising water and/or an organic solvent. 
     
     
         12 . A process for desulfurization of a refined crude oil fraction, comprising:
 mixing a ionic liquid composition according to  claim 1  with a batch of refined crude oil fraction in a mixing tank to manufacture an emulsion comprising at least the refined crude oil fraction and the ionic liquid composition;   feeding the emulsion through a catalytic reactor to bind at least S-compounds, and optionally other metals, of the refined crude oil fraction to the ionic liquid composition;   feeding the emulsion into a settling tank and storing the emulsion in said settling tank for a settling time (t) in order to leave the S-compounds bond to the ionic liquid composition to separate by gravity from a desulfurized refined crude oil fraction and to settle down in the settling tank;   
       wherein, optionally, the desulfurized refined crude oil fraction is then transferred to a storage or service tank; wherein, optionally, the settled ionic liquid composition containing S-compounds is then transferred to a flashing unit. 
     
     
         13 . The process of  claim 12 , wherein, before mixing the ionic liquid composition with the batch of refined crude oil fraction, the ionic liquid composition is mixed with demineralized water and then the mixture of ionic liquid composition and demineralized water is fed to the mixing tank ( 6 ) containing or configured to contain the batch of refined crude oil fraction. 
     
     
         14 . The process of  claim 12 , wherein, in the flashing unit, S-compounds are separated from the ionic liquid composition and form a residual sludge in the flashing unit; wherein the ionic liquid composition free of S-compounds is fed to a separate re-use tank to be reused in the process; wherein the residual sludge is transferred to a holding tank and, optionally, dried and packed for further handling. 
     
     
         15 . An apparatus for desulfurization of a refined crude oil fraction configured to perform the process of  claim 12 , wherein the apparatus comprises:
 a mixing tank having a first inlet in fluid communication with a tank of refined crude oil fraction;   a fresh ionic liquid composition tank and/or a re-use ionic liquid composition tank in fluid communication with a second inlet of the mixing tank;   at least one settling tank having an inlet in fluid communication with an outlet of the mixing tank; wherein said at least one settling tank has a first upper outlet for delivering desulfurized refined crude oil fraction and a second lower outlet for delivering settled ionic liquid composition containing S-compounds;   a catalytic reactor located between the outlet of the mixing tank and the inlet of said at least one settling tank.