Process for the hydroconversion of petroleum feedstocks via slurry technology allowing the recovery of metals from the catalyst and feedstock using a leaching 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, a liquid/liquid extraction step, a grinding step, a leaching 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′) using a solvent with a saturated nature in order to obtain a solid extract which is concentrated in metals and a raffinate;   d. a step for grinding the solid extract which is concentrated in metals obtained from the liquid/liquid extraction step;   e. a step for leaching the ground extract in the presence of water, a solvent with a saturated nature and a surfactant in order to obtain a solid extract and a leachate;   f. a step for combustion of said solid extract obtained from the leaching step in the presence of oxygen in order to obtain ash which is concentrated in metals;   g. a step for extraction of metals from the ash obtained in the combustion step;   h. 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 said light fraction obtained from step b) for separation without decompression undergoes at least one hydrotreatment and/or hydrocracking step. 
     
     
         3 . 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 one vacuum distillate fraction and one vacuum residue fraction, at least a portion, preferably all of said vacuum residue fraction being sent to the liquid/liquid extraction step, at least a portion, preferably all of said vacuum distillate fraction undergoing at least one hydrotreatment and/or hydrocracking step. 
     
     
         4 . A process according to  claim 1 , in which the liquid/liquid extraction step is carried out at a temperature in the range 50° C. to 300° C., preferably in the range 120° C. to 250° C. 
     
     
         5 . A process according to  claim 1 , in which the liquid/liquid extraction step is carried out with a solvent/feedstock ratio of 1/1 to 10/1, preferably 2/1 to 7/1. 
     
     
         6 . A process according to  claim 1 , in which the particle size of said solid extract which is concentrated in metals from the liquid/liquid extraction step obtained by grinding is less than 6 mm, preferably less than 4 mm. 
     
     
         7 . A process according to  claim 1 , in which the leaching step comprises:
 a. a step for preparing an emulsion comprising the ground extract from the grinding step, said water, said surfactant and said solvent with a saturated nature, the water/feedstock ratio being in the range 0.5/1 to 5/1, preferably in the range 1/1 to 2/1, the solvent/feedstock ratio being in the range 2/1 to 6/1, preferably in the range 3/1 to 4/1, and the concentration of surfactant being in the range 0.05% by weight to 2% by weight, preferably in the range 0.1% by weight to 1% by weight, with respect to the water;   b. a step for maturing said emulsion at a temperature in the range 20° C. to 120° C., preferably in the range 60° C. to 70° C., optionally for a period in the range 15 minutes to 3 hours;   c. a step for decanting, holding the temperature thereby, optionally for a period in the range 15 minutes to 30 hours, in order to obtain a solid extract and a leachate.   
     
     
         8 . A process according to  claim 1 , in which the solvent with a saturated nature used in the liquid/liquid extraction step and in the leaching step is identical and preferably selected from the group formed by hexane, heptane, and a light naphtha with a saturated nature, mixed or not mixed and in equal or different proportions. 
     
     
         9 . 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. 
     
     
         10 . A process according to  claim 1 , in which step g) for extraction of the metals comprises leaching using at least one acidic and/or basic solution. 
     
     
         11 . 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). 
     
     
         12 . 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 derivatives, oil shale or their derivatives, or mixtures of such feedstocks. 
     
     
         13 . 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. 
     
     
         14 . 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. 
     
     
         15 . 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.