Slurry hydroconversion with pitch recycle

Abstract

Systems and methods are provided for performing slurry hydroconversion of feeds that include substantial amounts of 1050° F+ (566° C+) components. The productivity of the slurry hydroconversion reaction is improved by recycling slurry hydroconversion pitch or bottoms back to the slurry hydroprocessing reaction system. The mass flow rate of the recycle stream can correspond to 50% or more of the mass flow rate of the fresh feed to the reaction system, and the recycle stream can include more than 50 wt % of 566° C+ components. It has been discovered that using a substantial recycle stream composed of a majority of unconverted 566° C+ bottoms can increase the productivity of the slurry hydroprocessing reaction system when operating at a net conversion relative to 524° C (975° F) of less than 90 wt %. Additionally, by using a recycle stream composed of a majority of 566° C+ components, the amount of lower boiling components (in the heavy hydrocarbon feed and/or in the recycle stream) that are exposed multiple times to the slurry hydroprocessing environment is reduced or minimized This can allow for formation of slurry hydroconversion products with increased amounts of vacuum gas oil boiling range components.

1 . A method for performing slurry hydroconversion, comprising:
 exposing a heavy hydrocarbon feed and a pitch recycle stream to a slurry hydroprocessing catalyst under slurry hydroconversion conditions in a reaction zone to form a slurry hydroprocessing effluent,
 the slurry hydroconversion conditions comprising a net conversion of 60 wt % to 89 wt % relative to 524° C, 
 the heavy hydrocarbon feed comprising 50 wt % or more of 566° C+ components, 
 the heavy hydrocarbon feed and the pitch recycle stream comprising a combined feed ratio of 1.5 to 3.5; and 
   separating the pitch recycle stream from the slurry hydroconversion effluent, the pitch recycle stream comprising more than 50 wt % of 566° C+ components.   
     
     
         2 . The method of  claim 1 , wherein the pitch recycle stream comprises 60 wt % or more of 566° C+ components, or wherein the pitch recycle stream comprises 50 wt % or more of 593° C+ components, or a combination thereof. 
     
     
         3 . The method of  claim 1 , wherein the heavy hydrocarbon feed comprises 60 wt % or more of 566° C+ components, or wherein the heavy hydrocarbon feed comprises 50 wt % or more of 593 ° C+ components, or a combination thereof. 
     
     
         4 . The method of  claim 1 , wherein the heavy hydrocarbon feed comprises 5 wt % to 80 wt % n-heptane asphaltenes, or wherein the heavy hydrocarbon feed comprises 5 wt % to 50 wt % micro carbon residue, or a combination thereof. 
     
     
         5 . The method of  claim 1 , wherein the combined feed ratio is 1.6 to 3.0. 
     
     
         6 . The method of  claim 1 , wherein the slurry hydroconversion conditions comprise 70 wt % to 89 wt % net conversion relative to 524° C. 
     
     
         7 . The method of  claim 1 , wherein the per-pass conversion at 524° C is lower than the net conversion at 524° C by 25 wt % or more, or wherein the per-pass conversion at 524 ° C is 60 wt % or less, or a combination thereof. 
     
     
         8 . The method of  claim 1 , wherein the slurry hydroconversion conditions comprise a temperature of 400° C to 480° C, a pressure of 1000 psig (˜6.4 MPa-g) to 3400 psig (−23.4 MPa-g), and a LHSV of 0.05 hr1 to 5 hr1. 
     
     
         9 . The method of  claim 1 , wherein at least a portion of the slurry hydroconversion catalyst comprises a catalyst formed in-situ. 
     
     
         10 . A slurry hydroconversion effluent made by the method comprising:
 exposing a heavy hydrocarbon feed and a pitch recycle stream to a slurry hydroprocessing catalyst under slurry hydroconversion conditions in a reaction zone to form a slurry hydroprocessing effluent,
 the slurry hydroconversion conditions comprising a net conversion of 60 wt % to 89 wt % relative to 524° C, 
 the heavy hydrocarbon feed comprising 50 wt % or more of 566° C+ components, 
 the heavy hydrocarbon feed and the pitch recycle stream comprising a combined feed ratio of 1.5 to 3.5; and 
   separating the pitch recycle stream from the slurry hydroconversion effluent, the pitch recycle stream comprising more than 50 wt % of 566° C+ components.