Process for Reducing the Asphaltene Yield and Recovering Waste Heat in a Pyrolysis Process by Quenching with a Hydroprocessed Product

Abstract

The invention relates to upgraded pyrolysis products, processes for upgrading products obtained from hydrocarbon pyrolysis, equipment useful for such processes, and the use of upgraded pyrolysis products.

1 . A hydrocarbon quenching process, comprising:
 (a) providing a first mixture comprising ≧10.0 wt. % hydrocarbon based on the weight of the first mixture;   (b) pyrolyzing the first mixture to produce a second mixture comprising ≧1.0 wt. % of C 2  unsaturates and ≧1.0 wt. % tar based on the weight of the second mixture, the second mixture and having a first temperature T 1 ;   (c) adding a quench fluid to the second mixture to produce a quenched mixture having a second temperature T 2 , wherein (i) T 1 >T z , (ii) T 1 −T 2 ≧100.0° C., and (iii) at least a portion of the resulting quenched mixture is liquid;   (d) separating from the quenched mixture a vapor stream and a tar stream; and   (e) contacting at least a first portion of the tar stream with at least one hydroprocessing catalyst under catalytic hydroprocessing conditions in the presence of molecular hydrogen to produce a hydroprocessed product, wherein the quench fluid comprises ≧5.0 wt. % of the hydroprocessed product based on the weight of the quench fluid.   
     
     
         2 . The process of  claim 1 , wherein the quench fluid further comprises a second portion of the tar stream in an amount ≧10.0 wt. % based on the weight of the quench fluid. 
     
     
         3 . The process of  claim 2 , wherein the second portion of the tar stream bypasses the hydroprocessing of step (e). 
     
     
         4 . The process of  claim 1 , wherein the hydroprocessed product comprises ≧10.0 wt. % of a hydroprocessed tar and ≧10.0 wt. % of a low-boiling mixture, the low boiling mixture having an ASTM D86 10% distillation point ≧60.0° C. and a 90% distillation point ≦350.0° C. 
     
     
         5 . The process of  claim 1 , wherein the first temperature T 1  is in the range of 600° C. to 850° C. 
     
     
         6 . The process of  claim 1 , wherein the second temperature T 2  is in the range of 250° C. to 500° C. 
     
     
         7 . The process of  claim 1 , wherein a third portion of the tar stream is withdrawn from the process. 
     
     
         8 . The process of  claim 1 , wherein a second portion of the hydroprocessed product is withdrawn from the process. 
     
     
         9 . The process of  claim 1 , wherein pyrolyzing in step (b) takes place in the presence of steam. 
     
     
         10 . The process of  claim 9 , wherein the pyrolyzing is steam cracking. 
     
     
         11 . A hydrocarbon quenching process, comprising:
 (a) providing a first mixture comprising ≧10.0 wt. % hydrocarbon based on the weight of the first mixture;   (b) pyrolyzing the first mixture to produce a second mixture comprising ≧1.0 wt. % of C 2  unsaturates and ≧1.0 wt. % tar based on the weight of the second mixture, the second mixture having a first temperature T 1 ,   (c) adding a quench fluid to the second mixture to produce a quenched mixture having a second temperature T 2 , wherein (i) T 1 >T z , (ii) T 1 −T 2 ≧100.0° C., and (iii) at least portion of the resulting quenched mixture is liquid;   (d) separating from the quenched mixture a vapor stream and a heavy tar stream;   (e) cooling the vapor stream to a third temperature T 3 , wherein T 2 >T 3  and T 2 −T 3 ≧50.0° C.;   (f) separating from the cooled vapor stream a second vapor stream and a light tar stream; and   (g) hydroprocessing the light tar stream to produce a hydroprocessed product, wherein the quench fluid comprises ≧5.0 wt. % of the hydroprocessed product based on the weight of the quench fluid.   
     
     
         12 . The process of  claim 11 , further comprising hydroprocessing at least a portion of the heavy tar stream to produce a second hydroprocessed product, wherein the quench fluid further comprises ≧5.0 wt. % of the second hydroprocessed product based on the weight of the quench fluid. 
     
     
         13 . The process in  claim 11 , further comprising (i) mixing a portion of the heavy tar stream from step (d) with a portion of the light tar stream from step (f) to form a mixed tar stream and (ii) hydroprocessing at least a portion of the mixed tar stream to produce a second hydroprocessed product, wherein the quench fluid further comprises ≧5.0 wt. % of the second hydroprocessed product based on the weight of the quench fluid. 
     
     
         14 . The process of  claim 11 , wherein the quench fluid further comprises a second portion of the light tar stream in an amount ≧10.0 wt. % based on the weight of the quench fluid. 
     
     
         15 . The process of  claim 11 , wherein the second portion of the light tar stream bypasses the hydroprocessing of step (g). 
     
     
         16 . The process of  claim 11 , wherein the first hydroprocessed product comprises ≧10.0 wt. % of a hydroprocessed tar and ≧10.0 wt. % of a low-boiling mixture, the low boiling mixture having an ASTM D86 10% distillation point ≧60.0° C. and a 90% distillation point ≦350.0° C., and the weight percents being based on the weight of the first hydroprocessed product. 
     
     
         17 . The process of  claim 11 , wherein T 1  is in the range of 600° C. to 850° C. 
     
     
         18 . The process of  claim 11 , wherein T 2  is in the range of 350° C. to 600° C. 
     
     
         19 . The process of  claim 11 , wherein T 3  is in the range of 300° C. to 500° C. 
     
     
         20 . The process of  claim 11 , further comprising conducting away at least a portion of the heavy tar stream. 
     
     
         21 . The process of  claim 11 , further comprising conducting away a third portion of the light tar stream. 
     
     
         22 . The process of  claim 11 , further comprising conducting away at least a portion of the first hydroprocessed product. 
     
     
         23 . The process of  claim 11 , wherein pyrolyzing in step (b) takes place in the presence of steam. 
     
     
         24 . The process of  claim 23 , wherein the pyrolyzing is steam cracking. 
     
     
         25 . The process of  claim 1 , wherein the hydroprocessing takes place in the presence of a supplemental utility fluid comprising aromatics and having an ASTM D86 10% distillation point ≧60° C. and a 90% distillation point ≦360° C.