Methods for processing hydrocarbons

Abstract

Methods for processing hydrocarbons may include passing a first portion of a catalyst to a first reaction zone and a second portion of the catalyst to a second reaction zone, contacting a hydrocarbon feed stream with the first portion of the catalyst to form a partially cracked hydrocarbon stream and a spent first portion of the catalyst, contacting the partially cracked hydrocarbon stream with the second portion of the catalyst to form a product and a spent second portion of the catalyst, removing at least a portion of hydrocarbons entrained within the spent first portion of the catalyst and the spent second portion of the catalyst in the stripper to form a stripped catalyst, regenerating at least a portion of the stripped catalyst to form a regenerated catalyst, and passing the regenerated catalyst to the first reaction zone and the second reaction zone.

1 . A method for processing hydrocarbons, the method comprising:
 passing a first portion of a catalyst to a first reaction zone and a second portion of the catalyst to a second reaction zone, wherein the first reaction zone and the second reaction zone are within a single reactor vessel;   contacting a hydrocarbon feed stream with the first portion of the catalyst in the first reaction zone to form a partially cracked hydrocarbon stream and a spent first portion of the catalyst, wherein the hydrocarbon feed stream has a net upward superficial velocity through the first reaction zone and the first portion of the catalyst has a net downward superficial velocity through the first reaction zone;   contacting the partially cracked hydrocarbon stream with the second portion of the catalyst in the second reaction zone to form a product and a spent second portion of the catalyst, wherein the product comprises one or more of ethylene, propylene, and butene, and wherein the partially cracked hydrocarbon stream and the second portion of the catalyst both have a net upward superficial velocity through the second reaction zone;   passing the spent first portion of the catalyst and the spent second portion of the catalyst to a stripper;   removing at least a portion of hydrocarbons entrained within the spent first portion of the catalyst and the spent second portion of the catalyst in the stripper to form a stripped catalyst;   regenerating at least a portion of the stripped catalyst to form a regenerated catalyst; and   passing the regenerated catalyst to the first reaction zone and the second reaction zone.   
     
     
         2 . The method of  claim 1 , wherein the first portion of the catalyst comprises from 30 wt. % to 70 wt. % of the catalyst. 
     
     
         3 . The method of  claim 1 , wherein an average particle size of the first portion of the catalyst is greater than an average particle size of the second portion of the catalyst. 
     
     
         4 . The method of  claim 1 , wherein one or both of:
 the first reaction zone operates with a turbulent fluidization regime; or   the second reaction zone operates with a fast fluidization regime.   
     
     
         5 . The method of  claim 1 , wherein the hydrocarbon feed stream comprises one or more of C 4  components, light naphtha, heavy naphtha, full range naphtha, vacuum gas oil, crude oil, FCC gasoline, olefinic naphtha, atmospheric residue, vacuum residue, condensate, deasphalted crude oil, dewaxed crude oil, deasphalted-dewaxed crude oil, kerosene, diesel or methanol. 
     
     
         6 . The method of  claim 1 , wherein one or both of:
 a residence time of the first portion of the catalyst in the first reaction zone is less than or equal to 60 seconds; or   a residence time of the second portion of the catalyst in the second reaction zone is less than or equal to 60 seconds.   
     
     
         7 . The method of  claim 1 , wherein one or more of:
 a residence time of the hydrocarbon feed stream in the first reaction zone and the second reaction zone is less than or equal to 15 seconds;   a temperature within the first reaction zone and the second reaction zone is from 420° C. to 750° C.; or   the catalyst comprises one or more of a USY zeolite and a ZSM-5 zeolite.   
     
     
         8 . The method of  claim 1 , wherein the partially cracked hydrocarbon stream is passed directly from the first reaction zone to the second reaction zone. 
     
     
         9 . The method of  claim 1 , wherein regenerating the at least a portion of the stripped catalyst comprises burning coke. 
     
     
         10 . The method of  claim 1 , comprising separating at least a portion of the product from the spent second portion of the catalyst. 
     
     
         11 . The method of  claim 1 , further comprising contacting the spent first portion of the catalyst with at least a portion of the hydrocarbon feed stream in a third reaction zone, wherein the hydrocarbon feed stream has a net upward superficial velocity through the third reaction zone and the spent first portion of the catalyst has a net downward superficial velocity through the third reaction zone. 
     
     
         12 . The method of  claim 1 , wherein the catalyst is passed through a catalyst distributor positioned from 5% to 40% of a distance from a top of the second reaction zone to a bottom of the first reaction zone. 
     
     
         13 . The method of  claim 12 , wherein the catalyst distributor comprises from 2 to 12 tubular branches, each tubular branch comprising a plurality of orifices on a circumferential portion of the tubular branch, wherein the tubular branches are spaced apart radially at an angle from 30° to 180°. 
     
     
         14 . The method of  claim 12 , wherein the catalyst distributor comprises a top perforated plate, a bottom perforated plate, a distributor wall extending from the top perforated plate to the bottom perforated plate, and a conduit extending from an opening in the distributor wall to a catalyst inlet in a wall of the reactor vessel, such that catalyst exits the catalyst distributor in an upward or downward vertical direction. 
     
     
         15 . The method of  claim 12 , wherein the catalyst distributor comprises a perforated plate extending across the reactor vessel, the perforated plate comprising a first plurality of perforations and a second plurality of perforations, wherein the first plurality of perforations are proximate a catalyst inlet in the wall of the reactor vessel and of the first plurality of perforations have an average area less than an average area of the second plurality of perforations. 
     
     
         16 . The method of  claim 1 , wherein the first reaction zone operates with a turbulent fluidization regime. 
     
     
         17 . The method of  claim 1 , wherein the second reaction zone operates with a fast fluidization regime. 
     
     
         18 . The method of  claim 1 , wherein:
 the first portion of the catalyst comprises from 30 wt. % to 70 wt. % of the catalyst; and   an average particle size of the first portion of the catalyst is greater than an average particle size of the second portion of the catalyst.   
     
     
         19 . The method of  claim 1 , wherein a residence time of the first portion of the catalyst in the first reaction zone is less than or equal to 60 seconds. 
     
     
         20 . The method of  claim 1 , wherein a residence time of the second portion of the catalyst in the second reaction zone is less than or equal to 60 seconds.