Method for the hydroconversion of oil feedstocks using slurry technology, allowing the recovery of metals from the catalyst and the feedstock, comprising an extraction step

Abstract

A process for the hydroconversion of heavy oil feedstocks comprises a step for hydroconversion of the feedstock in at least one reactor containing a catalyst in slurry mode used to recover metals from the residual unconverted fraction, especially those used as catalysts. The process comprises a hydroconversion step, a gas/liquid separation step, at least one liquid/liquid extraction step, a combustion step, a metals extraction step and a step for the preparation of catalytic solutions which are recycled to the hydroconversion step.

1 . A process for the hydroconversion of heavy oil feedstocks containing metals, comprising:
 a) a step for hydroconversion of the feedstock in at least one reactor containing a catalyst in the form of a slurry containing at least one metal, and optionally a solid additive;   b) a step for separation of the hydroconversion effluent without decompression into a fraction termed the light fraction containing compounds boiling at 500° C. at most and into a residual fraction;   b′) an optional step for fractionation, comprising vacuum separation of said residual fraction as obtained in step b) to obtain a vacuum residue which is concentrated in metals;   c) a step for liquid/liquid extraction of said residual fraction as obtained in step b) and/or said vacuum residue as obtained in step b′) at a temperature in the range 50° C. to 350° C. using an aromatic and/or naphtheno-aromatic and/or polar solvent in order to obtain an extract which is concentrated in metals and a raffinate;   d) a step for combustion of said extract at a temperature in the range 200° C. to 700° C. in order to obtain ash which is concentrated in metals;   e) a step for extraction of metals from the ash obtained in the combustion step;   f) a step for preparing metallic solution(s) containing at least the metal of the catalyst which is/are recycled as the catalyst to the hydroconversion step.   
     
     
         2 . A process according to  claim 1 , in which the liquid/liquid extraction step is carried out at a temperature in the range 150° C. to 350° C. 
     
     
         3 . A process according to one of the preceding claims  claim 1 , in which the liquid/liquid extraction step is carried out with a solvent/feedstock ratio of 0.5/1 to 20/1, preferably 1/1 to 5/1. 
     
     
         4 . A process according to  claim 1 , in which the raffinate from the liquid/liquid extraction step undergoes a second liquid/liquid extraction step at a temperature in the range 50° C. to 300° C. using a paraffinic solvent. 
     
     
         5 . A process according to  claim 1 , in which the second liquid/liquid extraction step is carried out with a solvent/feedstock ratio of 1/1 to 10/1, preferably 2/1 to 7/1, and at a temperature in the range 50° C. to 300° C., preferably in the range 120° C. to 250° C. 
     
     
         6 . A process according to  claim 1 , in which said “light” fraction from the step for separation without decompression undergoes at least one hydrotreatment and/or hydrocracking step. 
     
     
         7 . A process according to  claim 1 , in which said residual fraction from the step for separation without decompression is fractionated by vacuum distillation into at least a vacuum distillate and a vacuum residue, at least a portion and preferably all of said vacuum residue being sent to the liquid/liquid extraction step, at least a portion and preferably all of said vacuum distillate undergoing at least one hydrotreatment and/or hydrocracking step. 
     
     
         8 . A process according to  claim 1 , in which the combustion step is operated at a pressure of −0.1 to 1 MPa, preferably −0.1 to 0.5 MPa and at a temperature of 200° C. to 700° C., preferably 400° C. to 550° C. in the presence of air. 
     
     
         9 . A process according to  claim 1 , in which the step for extraction of the metals comprises leaching using at least one acidic and/or basic solution. 
     
     
         10 . A process according to  claim 1 , in which the heavy oil feedstock is a hydrocarbon feedstock containing at least 50% by weight of product distilling above 250° C. and at least 25% by weight distilling above 350° C., and contains at least 50 ppm by weight of metals, at least 0.5% by weight of sulphur and at least 1% by weight of asphaltenes (heptane asphaltenes). 
     
     
         11 . A process according to  claim 1 , in which the heavy oil feedstock is selected from oil residues, crude oils, topped crudes, deasphalted oils, deasphalted asphalts, oil conversion process derivatives, bituminous sands or their derivative, oil shale or their derivatives, or mixtures of such feedstocks. 
     
     
         12 . A process according to  claim 1 , in which the hydroconversion step is operated at a pressure of 2 to 35 MPa, preferably 10 to 25 MPa, a partial pressure of hydrogen of 2 to 35 MPa, preferably 10 to 25 MPa, a temperature in the range 300° C. to 500° C., preferably 420° C. to 480° C. and a contact time of 0.1 h to 10 h, preferably 0.5 h to 5 h. 
     
     
         13 . A process according to  claim 1 , in which the slurry catalyst is a sulphurized catalyst containing at least one element selected from the group formed by Mo, Fe, Ni, W, Co, V and Ru. 
     
     
         14 . A process according to  claim 1 , in which the additive is selected from the group formed by mineral oxides, spent supported catalysts containing at least one element from group VIII and/or at least one element from group VIB, carbonaceous solids with a low hydrogen content or mixtures of said additives, said additive having a particle size of less than 1 mm