Deep hydroconversion process using an extraction of aromatics and resins, with upgrading of the hydroconversion extract and raffinate in downstream units

Abstract

Process for deep conversion of heavy hydrocarbon feed, which includes: a) ebullated bed hydroconverting the feed in at least one three-phase reactor containing at least one supported hydroconversion catalyst; b) atmospheric fractionating effluent from a) producing gasoline fraction, gas oil cut, and atmospheric residue; c) vacuum fractionation of at least a portion of the atmospheric residue to obtain a vacuum gas oil fraction and an unconverted vacuum residue fraction; d) deasphalting at least a portion of the unconverted vacuum residue fraction with an organic solvent obtaining a hydrocarbon cut depleted in asphaltenes, termed deasphalted oil, and residual asphalt; and e) liquid/liquid extraction on the hydrocarbon cut depleted in asphaltenes extracting aromatics by a polar solvent producing an extract enriched in aromatics and resins and a raffinate depleted in aromatics and resins, at least a portion of the extract sent to the inlet of the hydroconversion as an aromatic diluent.

1 . A process for deep conversion of a heavy hydrocarbon feed, comprising the following steps:
 a) ebullated bed hydroconversion of the feed, in the presence of hydrogen, in a hydroconversion section comprising at least one three-phase reactor containing at least one supported hydroconversion catalyst,   b) atmospheric fractionation of at least a portion of the hydroconverted liquid effluent obtained from step a) in an atmospheric fractionation section in order to produce a fraction comprising a gasoline cut and a gas oil cut, and an atmospheric residue;   c) vacuum fractionation of at least a portion of the atmospheric residue obtained from step b) in a vacuum fractionation section in order to obtain a vacuum gas oil fraction comprising light vacuum distillates (LVGO) and heavy vacuum distillates (HVGO) and an unconverted vacuum residue fraction,   d) deasphalting at least a portion of the unconverted vacuum residue fraction obtained from step c) in a deasphalting section by means of an organic solvent under conditions for obtaining a hydrocarbon cut depleted in asphaltenes, termed deasphalted oil, and residual asphalt,   e) liquid/liquid extraction carried out on the hydrocarbon cut depleted in asphaltenes in a section for the extraction of aromatics by means of a polar solvent under conditions for extracting aromatics in order to produce an extract enriched in aromatics and resins and a raffinate depleted in aromatics and resins, at least a portion of the extract being sent to the inlet to the hydroconversion section as an aromatic diluent.   
     
     
         2 . The process as claimed in  claim 1 , comprising:
 a step f1) for hydrocracking at least a portion of the raffinate obtained from the extraction step e) in a reactor comprising at least one fixed bed of hydrocracking catalyst in order to produce a gasoline fraction, a gas oil fraction (GO), vacuum gas oil (VGO) and an unconverted oil fraction (UCO),   and/or a step f2) for fluidized bed catalytic cracking of at least a portion of the raffinate obtained from the extraction e) in a fluidized bed reactor in order to produce a gaseous fraction, a gasoline fraction, a gas oil fraction and a heavy residual fraction termed slurry.   
     
     
         3 . The process as claimed in  claim 2 , in which the unconverted oil fraction obtained from hydrocracking and/or the heavy residual fraction obtained from catalytic cracking are sent to the aromatics extraction section. 
     
     
         4 . The process as claimed in  claim 1 , in which a portion of the extract is used as a flux oil as a mixture with residual asphalt produced by the deasphalting step d) in order to provide a liquid fuel or to form part of the bitumen composition or to be supplied to a coking unit. 
     
     
         5 . The process as claimed in  claim 2 , in which the raffinate produced by the aromatics extraction unit is sent to the hydrocracking unit and/or to the catalytic cracking unit together with one or more other feeds selected from straight run vacuum gas oil (straight run VGO) and light (LVGO) and heavy vacuum distillates (HVGO) obtained from the outlet from the vacuum fractionation c). 
     
     
         6 . The process as claimed in  claim 1 , in which at least a portion of the light vacuum distillate (LVGO) or of the heavy vacuum distillate (HVGO) is sent to the aromatics extraction section. 
     
     
         7 . The process as claimed in  claim 1 , in which a portion of the atmospheric residue is sent directly to the deasphalting section. 
     
     
         8 . The process as claimed in  claim 1 , in which the hydroconversion step a) is operated at an absolute pressure in the range 5 to 35 MPa, at a weighted average catalytic bed temperature of 300° C. to 600° C., at an hourly space velocity of 0.1 h −1  to 10 h −1  and at a ratio of hydrogen to feed H 2 /HC of 200 to 1000 m 3 /m 3 . 
     
     
         9 . The process as claimed in  claim 2 , in which the hydrocracking step f1) is operated at an average catalytic bed temperature in the range 300° C. to 550° C., a pressure in the range 5 to 35 MPa, and a liquid space velocity in the range 0.1 to 10 h −1 . 
     
     
         10 . The process as claimed in  claim 2 , in which the fluidized bed catalytic cracking step f2) is operated in upflow mode with a reactor outlet temperature in the range 520° C. to 600° C., a C/O ratio in the range 6 to 14, and a dwell time in the range 1 to 10 s, or in downflow mode with a reactor outlet temperature in the range 580° C. to 630° C., a C/O ratio in the range 15 to 40, and with a dwell time in the range 0.1 to 1 s. 
     
     
         11 . The process as claimed in  claim 1 , in which the deasphalting step is carried out in an extraction column, the solvent comprising at least 50% by weight of hydrocarbon compounds containing 3 to 7 carbon atoms, the extracter head temperature being in the range 50° C. to 250° C., the extracter bottom temperature being in the range 30° C. to 220° C., and the pressure being in the range 2 to 10 MPa. 
     
     
         12 . The process as claimed in  claim 11 , in which the solvent is butane. 
     
     
         13 . The process as claimed in  claim 1 , in which the liquid/liquid extraction is carried out with the aid of a solvent selected from furfural, N-methyl-2-pyrrolidone (NMP), sulfolane, dimethylformamide (DMF), dimethylsulphoxide (DMSO), phenol, or a mixture of these solvents in equal or different proportions, with a solvent/feed ratio of 0.5/1 to 3/1, at a temperature in the range between ambient temperature and 150° C., and at a pressure in the range between atmospheric pressure and 2 MPa. 
     
     
         14 . The process as claimed in  claim 1 , in which the feed is selected from heavy hydrocarbon feeds of the atmospheric residue or vacuum residue type obtained, for example, by straight run distillation of an oil cut or by vacuum distillation of crude oil, distillate type feeds such as vacuum gas oil or deasphalted oils, asphaltenes obtained by solvent deasphalting oil residues, coal in suspension in a hydrocarbon fraction such as gas oil obtained from vacuum distillation of crude oil, for example, or in fact the distillate obtained from coal liquefaction, alone or as a mixture.