Process for hydroconversion of petroleum feedstocks via a slurry technology allowing the recovery of metals from the catalyst and from the feedstock using a coking step

Abstract

A process for hydroconversion of heavy petroleum feedstocks comprising a hydroconversion step of the feedstock in at least one reactor containing a slurry catalyst and allowing the recovery of metals in the unconverted residual fraction, in particular those used as catalysts, The process comprises a hydroconversion step, a gas/liquid separation step, a coking step, a combustion step, a metals extraction step and a step of preparing catalytic solutions which are recycled to the hydroconversion step.

1 . Process for hydroconversion of heavy petroleum feedstocks containing metals comprising:
 a) a step of hydroconversion of the feedstock in at least one reactor containing a slurry catalyst containing at least one metal, and optionally a solid additive,   b) a step of separation of the hydroconversion effluent without decompression into a so-called light fraction containing the compounds boiling at a maximum temperature of 500° C. and a residual fraction,   b′) optionally a fractionation step comprising a separation under vacuum of said residual fraction as obtained in step b), and a vacuum residue with a high concentration of metals is obtained,   c) a step of coking of said residual fraction as obtained in step b) and/or of said vacuum residue as obtained in step b′) making it possible to obtain a solid effluent containing coke,   d) a step of combustion of said solid effluent containing coke at a temperature comprised between 200 and 700° C. making it possible to obtain ashes with a high concentration of metals,   e) a step of extraction of the metals from the ashes obtained in the combustion step,   f) a step of preparation of metallic solution(s) containing at least the metal of the catalyst which is/are recycled(s) as catalyst in the hydroconversion step.   
     
     
         2 . Process according to  claim 1  in which said so-called light fraction originating from the separation step without decompression is subjected to at least one hydrotreatment and/or hydrocracking step. 
     
     
         3 . Process according to  claim 1 , in which the coking step is delayed coking and takes place at a temperature at the outlet from the feedstock heating ovens comprised between 460 and 530° C., preferably 480 and 510° C., and a temperature at the outlet from the maturation vessels greater than 420° C., preferably comprised between 430 and 490° C., and a pressure less than 0.5 MPa, preferably of 0.1 to 0.3 MPa, under an inert atmosphere. 
     
     
         4 . Process according to  claim 1  in which the combustion step takes place at a temperature of 400 to 550° C., in the presence of oxygen. 
     
     
         5 . Process according to  claim 1  in which the combustion step takes place at a pressure of −0.1 to 1 MPa, preferably −0.1 to 0.5 MPa and at a temperature of 400 to 550° C., in the presence of oxygen. 
     
     
         6 . Process according to  claim 1 , in which the step of extraction of the metals comprises leaching by at least one acid and/or basic solution. 
     
     
         7 . Process according to  claim 1  in which said residual fraction originating from the separation step without decompression is fractionated by vacuum distillation into at least one vacuum distillate fraction and one vacuum residue fraction, at least part and preferably all of said vacuum residue fraction being sent to the coking step, at least part and preferably all of said vacuum distillate fraction being subjected to at least one hydrotreatment and/or hydrocracking step. 
     
     
         8 . Process according to  claim 1  in which part of the solid effluent containing coke from the coking step is recycled as an additive in the hydroconversion step. 
     
     
         9 . Process according to  claim 1  in which the heavy petroleum 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). 
     
     
         10 . Process according to  claim 1  in which the heavy petroleum feedstock is chosen from petroleum residues, crude oils, topped crude oils, deasphalted oils, asphalts or deasphalting pitches, derivatives from petroleum conversion processes, bituminous sands or derivatives thereof, bituminous shales or derivatives thereof, or mixtures of such feedstocks. 
     
     
         11 . Process according to  claim 1  in which the hydroconversion step takes place at a pressure of 2 to 35 MPa, preferably 10 to 25 MPa, a partial hydrogen pressure of 2 to 35 MPa, preferably 10 to 25 MPa, a temperature comprised between 300° C. and 500° C., preferably from 420° C. to 480° C. and a contact time of 0.1 hour to 10 hours, preferably 0.5 hour to 5 hours. 
     
     
         12 . Process according to  claim 1  in which the slurry catalyst is a sulphide catalyst containing at least one element chosen from the group formed by Mo, Fe, Ni, W, Co, V, Ru. 
     
     
         13 . Process according to  claim 1  in which the additive is chosen from the group formed by the mineral oxides, supported spent catalysts containing at least one Group VIII element and/or at least one Group VIB element, carbonaceous solids with a low hydrogen content or mixtures of such additives, said additive having a particle size of less than 1 mm