Method of conversion of residues comprising 2 deasphaltings in series

Abstract

The invention relates to a method of conversion of heavy oil feedstock with 5 wt. % boiling less than 343C and at least 40 wt. % of molecules boiling above 540C, comprising: a first deasphalting with a heavy solvent constituted essentially of a saturated hydrocarbon having at least 5 carbon atoms, a second deasphalting on the unprecipitated fraction obtained from the first deasphalting (called first unprecipitated fraction), with a light solvent constituted essentially of a saturated hydrocarbon having 3 or 4 carbon atoms, the second unprecipitated fraction obtained from the 2 nd deasphalting is converted by catalytic cracking to products boiling below 343C, the precipitated fractions are mixed together and treated by hydroconversion to products boiling above 540C, the hydroconversion being carried out in a fluidized bed or in a slurry at least one portion of the aromatic cuts boiling above 220C obtained in the catalytic cracking is added to at least one of the precipitated fractions before the hydroconversion.

1 . Method of conversion of heavy oil feedstock with 5 wt. % boiling at least 343° C. and at least 40 wt. % of molecules boiling above 540° C., comprising:
 a first deasphalting with a heavy solvent constituted essentially of a saturated hydrocarbon having at least 5 carbon atoms,   a second deasphalting on the unprecipitated fraction obtained from the first deasphalting (called first unprecipitated fraction), with a light solvent constituted essentially of a saturated hydrocarbon having 3 or 4 carbon atoms,   the second unprecipitated fraction obtained from the 2nd deasphalting is converted by catalytic cracking to products boiling above 343° C.,   the precipitated fractions are mixed together and treated by hydroconversion to products boiling above 540° C., the hydroconversion being carried out in a fluidized bed or in slurry   at least one portion of the aromatic cuts boiling above 220° C. obtained in the catalytic cracking is added to at least one of the precipitated fractions before the hydroconversion.   
     
     
         2 . Method according to  claim 1  wherein the solvent in the first deasphalting is an n-paraffin having from 5 to 7 carbon atoms and the solvent in the second deasphalting is an n-paraffin having at least 3 or 4 carbon atoms. 
     
     
         3 . Method according to  claim 1  wherein the solvent in the first deasphalting is n-pentane and the solvent in the second deasphalting is propane or n-butane. 
     
     
         4 . Method according to  claim 1  wherein all of the aromatic cuts heavier than gasoline obtained in the catalytic cracking are added to at least one of the precipitated fractions before hydroconversion. 
     
     
         5 . Method according to  claim 1  wherein the feed is a vacuum residue obtained from atmospheric distillation of a petroleum crude, and a vacuum distillate is sent to catalytic cracking mixed with said second unprecipitated fraction. 
     
     
         6 . Method according to  claim 1  wherein the feed is a vacuum residue obtained from atmospheric distillation of a petroleum crude, and a vacuum distillate is sent to a catalytic cracking different from the catalytic cracking in which said second unprecipitated fraction is treated. 
     
     
         7 . Method according to  claim 1  wherein the feed is a vacuum residue obtained from atmospheric distillation of a petroleum crude, and a vacuum distillate is treated by hydrocracking.