Fluidized coking with reduced coking via light hydrocarbon addition

Abstract

Systems and methods are provided for adding a heated stream of light hydrocarbons to a fluidized coking environment to improve liquid product yield and/or reduce coke production. The light hydrocarbons can correspond to C 1 -C 10 hydrocarbons and/or hydrogen. The light hydrocarbons can be heated so that the light hydrocarbons are exposed to an activation temperature of 535° C. to 950° C. and/or an activation temperature higher than the temperature in the coking zone by 50° C. or more for an activation time prior to entering the fluidized coking reactor and/or the coking zone in the fluidized coking environment.

1 . A method for performing fluidized coking on a feedstock, comprising:
 activating a stream comprising C 1 -C 10  hydrocarbons, hydrogen, or a combination thereof by exposing the stream comprising C 1 -C 10  hydrocarbons, hydrogen, or a combination thereof to an activation temperature for an activation time of 0.1 seconds to 10 seconds, the activation temperature being higher than a coking zone temperature by 50° C. or more; and   exposing, in a reactor, a feedstock comprising a T10 distillation point of 343° C. or more to a fluidized bed comprising solid particles in the presence of the activated stream under fluidized coking conditions comprising the coking zone temperature to form a coker effluent, the fluidized coking conditions comprising 10 wt % or more conversion of the feedstock relative to 343° C., the fluidized coking conditions being effective for depositing coke on the solid particles.   
     
     
         2 . The method of  claim 1 , wherein the stream comprising C 1 -C 10  hydrocarbons, hydrogen, or a combination thereof comprises C 1 -C 5  alkanes, or wherein the stream comprising C 1 -C 10  hydrocarbons, hydrogen, or a combination thereof comprises at least one of C 7 -C 10  alkylaromatics and naphthenoaromatics, or a combination thereof. 
     
     
         3 . The method of  claim 1 , wherein the activation temperature is 535° C. to 950° C. 
     
     
         4 . The method of  claim 1 , wherein the activation temperature is greater than the coking zone temperature by 100° C. or more. 
     
     
         5 . The method of  claim 1 , wherein the coking zone temperature is 650° C. or less. 
     
     
         6 . The method of  claim 1 , wherein the activation time is 0.1 seconds to 1.0 seconds. 
     
     
         7 . The method of  claim 1 , wherein the activation time is 6.0 seconds to 10 seconds. 
     
     
         8 . The method of  claim 1 , wherein the feedstock is exposed to the fluidized bed comprising solid particles under the fluidized coking conditions in a coking zone, the activated stream being exposed to the activation temperature for the activation time prior to entering the coking zone. 
     
     
         9 . The method of  claim 1 , wherein the feedstock is exposed to the fluidized bed comprising solid particles under the fluidized coking conditions without being exposed to an additional cracking catalyst under the fluidized coking conditions. 
     
     
         10 . The method of  claim 1 , further comprising activating the stream comprising C 1 -C 10  hydrocarbons, hydrogen, or a combination thereof by introducing the stream comprising C 1 -C 10  hydrocarbons, hydrogen, or a combination thereof into a conduit containing heated coke particles, the conduit providing direct fluid communication between the reactor and at least one of a heater and a gasifier. 
     
     
         11 . The method of  claim 1 , further comprising introducing the activated stream into a coking zone of the reactor using one or more nozzles. 
     
     
         12 . The method of  claim 1 , wherein the reactor comprises a stripping zone below a coking zone, the method further comprising introducing the activated stream into the reactor as part of a stripping gas introduced into the stripping zone. 
     
     
         13 . The method of  claim 1 , further comprising introducing the activated stream into the reactor as a fluidizing gas for the fluidized bed. 
     
     
         14 . The method of  claim 10 , wherein a mass flow rate of steam into the reactor relative to the mass flow rate of feedstock into the reactor is 6.0% or less. 
     
     
         15 . A method for performing fluidized coking on a feedstock, comprising:
 activating a stream comprising C 1 -C 10  hydrocarbons, hydrogen, or a combination thereof by exposing the stream to an activation temperature for and activation time of 0.1 seconds to 10 seconds, the activation temperature being higher than a coking zone temperature by 50° C. or more;   exposing, in a reactor, a feedstock comprising a T10 distillation point of 343° C. or more to a fluidized bed comprising solid particles in the presence of the activated stream under fluidized coking conditions comprising the coking zone temperature to form a coker effluent, the fluidized coking conditions comprising 10 wt % or more conversion of the feedstock relative to 343° C., the fluidized coking conditions being effective for depositing coke on the solid particles;   introducing an oxygen-containing stream and steam into a coke combustion stage;   passing at least a portion of the solid particles comprising deposited coke from the reactor to the coke combustion stage;   exposing the at least a portion of the solid particles comprising deposited coke to combustion conditions to form a gas phase product comprising H 2 , CO, and CO 2  and partially combusted solid particles;   removing at least a first portion of the partially combusted solid particles from the coke combustion stage;   passing at least a second portion of the partially combusted solid particles from the coke combustion stage to the reactor; and   separating the coker effluent to form a lower boiling product comprising at least a portion of the stream comprising C 1 -C 10  hydrocarbons, hydrogen, or a combination thereof.   
     
     
         16 . The method of  claim 15 , wherein the coke combustion stage comprises a gasifier. 
     
     
         17 . The method of  claim 15 , wherein the solid particles comprise coke particles. 
     
     
         18 . The method of  claim 1 , wherein the activation time is 0.1 seconds to 1.0 seconds, or wherein the activation time is 6.0 seconds to 10 seconds. 
     
     
         19 . An integrated fluidized coking system, comprising:
 a fluidized bed coker comprising a coker feed inlet, an activated gas inlet, a cold coke outlet, at least one hot coke inlet, and a coker product outlet;   a coke combustion reactor comprising:
 a coke combustion inlet in fluid communication with the cold coke outlet, 
 a coke combustion outlet in fluid communication with the at least one hot coke inlet via at least one hot coke conduit, 
 at least one coke combustion gas inlet, and 
 a fuel gas outlet; 
   a first separation stage comprising a first separation stage inlet in fluid communication with the coker product outlet, a first separation stage heavy product outlet and a first separation stage light ends outlet, the first separation stage light ends outlet being in fluid communication with the activated gas inlet via an activated gas conduit; and   a heater associated with the activated gas conduit for heating gas in the activated gas conduit.   
     
     
         20 . The system of  claim 19 , wherein the fluidized bed coker comprises a coking zone and a stripping zone, the activated gas inlet comprising a stripping gas inlet, a fluidizing gas inlet, or a combination thereof. 
     
     
         21 . The system of  claim 19 , wherein the coke combustion reactor comprises a gasifier, the at least one coke combustion gas inlet comprising at least one gasifier gas inlet. 
     
     
         22 . The system of  claim 19 , wherein the at least one hot coke inlet is in fluid communication with a coking zone of the reactor, or wherein the at least one hot coke inlet is in fluid communication with a stripping zone of the reactor, or a combination thereof.