Self-heat-balanced hsfcc systems and processes for upgrading hydrocarbon feeds

Abstract

A process for upgrading hydrocarbon feeds in an FCC system includes passing portions of a heavy hydrocarbon feed to a first reactor and a second reactor and passing portions of a light hydrocarbon feed to a third reactor and a fourth reactor. The heavy hydrocarbon feed has an API gravity of from 10° to 35° and the light hydrocarbon feed has an API gravity of from 38° to 100°. A cracking catalyst is passed to the reactors and contacted with the portions of the heavy and light hydrocarbon feeds. Reaction mixtures from the reactors are separated to produce an FCC effluent and spent cracking catalyst. The spent cracking catalyst is regenerated and passed back to the reactors. A flow rate of the cracking catalyst to the reactors is controlled based on determined heat balance requirements of each of the reactors.

What is claimed is: 
     
         1 . A process for upgrading hydrocarbon feeds in a fluidized catalytic cracking system (FCC system), the process comprising:
 passing a first portion of a heavy hydrocarbon feed to a first FCC reactor and a second portion of the heavy hydrocarbon feed to a second FCC reactor, where the heavy hydrocarbon feed has an American Petroleum Institute (API) gravity of from 10° to 35°;   passing a first portion of a light hydrocarbon feed to a third FCC reactor and second portion of the light hydrocarbon feed to a fourth FCC reactor, where the light hydrocarbon feed has an API gravity of from 38° to 100°;   passing a cracking catalyst from a catalyst withdrawal well to the first FCC reactor, the second FCC reactor, the third FCC reactor, and the fourth FCC reactor, where the catalyst withdrawal well is common to the first FCC reactor, the second FCC reactor, the third FCC reactor, and the fourth FCC reactor and the first FCC reactor, the second FCC reactor, the third FCC reactor, and the fourth FCC reactor are operated in parallel;   contacting the first portion and the second portion of the heavy hydrocarbon feed with the cracking catalyst in the first FCC reactor and the second FCC reactor, respectively, at high severity conditions, where the contacting causes at least a portion of the heavy hydrocarbon feed to undergo catalytic cracking;   contacting the first portion and the second portion of the light hydrocarbon feed with the cracking catalyst in the third FCC reactor and the fourth FCC reactor, respectively, at high severity conditions, where the contacting causes at least a portion of the light hydrocarbon feed to undergo catalytic cracking;   separating reaction mixtures from the first FCC reactor, the second FCC reactor, the third FCC reactor, and the fourth FCC reactor to produce an FCC effluent and spent cracking catalyst;   regenerating the spent cracking catalyst to produce regenerated catalyst;   passing the regenerated catalyst back to the catalyst withdrawal well;   determining a heat balance requirement of the first FCC reactor, the second FCC reactor, the third FCC reactor, and the fourth FCC reactor; and   controlling a flow rate of the cracking catalyst from the catalyst withdrawal well to the first FCC reactor, the second FCC reactor, the third FCC reactor, and the fourth FCC reactor, based on the heat balance requirements of the first FCC reactor, the second FCC reactor, the third FCC reactor, and the fourth FCC reactor.   
     
     
         2 . The process of  claim 1 , wherein regenerating the spent catalyst occurs in a common regenerator. 
     
     
         3 . The process of  claim 2 , wherein the common regenerator is operated without supplemental fuel or catalyst coolers. 
     
     
         4 . The process of  claim 1 , wherein separating the reaction mixtures of the first FCC reactor, the second FCC reactor, the third FCC reactor, and the fourth FCC reactor comprises:
 passing the reaction mixtures from the first FCC reactor, the second FCC reactor, the third FCC reactor, and the fourth FCC reactor to a common fluid-solid separator; and   separating the reaction mixtures in the common fluid-solid separator to produce the FCC effluent and the spent cracking catalyst.   
     
     
         5 . The process of  claim 1 , wherein controlling the flow rate comprises operating a first valve, a second valve, a third valve, and a fourth valve to control the flow rate of the cracking catalyst passed from the catalyst withdrawal well to the first FCC reactor, the second FCC reactor, the third FCC reactor, and the fourth FCC reactor, respectively. 
     
     
         6 . The process of  claim 5 , wherein the first valve is disposed between the catalyst withdrawal well and the first FCC reactor, the second valve is disposed between the catalyst withdrawal well and the second FCC reactor, the third valve is disposed between the catalyst withdrawal well and the third FCC reactor, and the fourth valve is disposed between the catalyst withdrawal well and the fourth FCC reactor. 
     
     
         7 . The process of  claim 1 , wherein controlling the flow rate comprises detecting an amount of coke on the spent cracking catalyst. 
     
     
         8 . The process of  claim 1 , wherein controlling the flow rate comprises determining a heat balance requirement of the first FCC reactor, the second FCC reactor, the third FCC reactor, and the fourth FCC reactor. 
     
     
         9 . The process of  claim 1 , wherein controlling the flow rate comprises:
 detecting an amount of coke on the spent cracking catalyst;   determining a heat balance requirement of the first FCC reactor, the second FCC reactor, the third FCC reactor, and the fourth FCC reactor;   comparing the amount of coke to the heat balance requirements of the first FCC reactor, the second FCC reactor, the third FCC reactor, and the fourth FCC reactor; and   operating a first valve, a second valve, a third valve, and a fourth valve to adjust a catalyst-to-oil ratio in the first FCC reactor, the second FCC reactor, the third FCC reactor, and the fourth FCC reactor, wherein adjusting the catalyst-to-oil ratio changes a reactor outlet temperature of the first FCC reactor, the second FCC reactor, the third FCC reactor, the fourth FCC reactor, or combinations thereof.   
     
     
         10 . The process of  claim 1 , wherein a cracking temperature of the first FCC reactor and the second FCC reactor is within 100° C. of a cracking temperature of the third FCC reactor and the fourth FCC reactor. 
     
     
         11 . The process of  claim 1 , wherein:
 the heavy hydrocarbon feed has an API gravity of from 10° to 30°;   the light hydrocarbon feed has an API gravity of from 40° to 100°;   a catalyst-to-oil ratio of the first FCC reactor, the second FCC reactor, the third FCC reactor, and the fourth FCC reactor is from 3:1 to 50:1.   
     
     
         12 . The process of  claim 1 , wherein regenerating the spent cracking catalyst comprises combusting coke deposited on the spent cracking catalyst. 
     
     
         13 . The process of  claim 1 , where the heavy hydrocarbon feed is a whole crude oil. 
     
     
         14 . The process of  claim 1 , wherein the light hydrocarbon feed comprises a light crude oil, an extra light crude oil, or a gas condensate. 
     
     
         15 . The process of  claim 1 , wherein the API gravity of the light hydrocarbon feed is at least 25° higher than the API gravity of the heavy hydrocarbon feed. 
     
     
         16 . The process of  claim 1 , wherein the light hydrocarbon feed, the heavy hydrocarbon feed, or both are hydrotreated feed streams. 
     
     
         17 . The process of  claim 1 , wherein:
 the first FCC reactor and the second FCC reactor converts from 8 wt. % to 11 wt. % of the heavy hydrocarbon feed to coke; and   the third FCC reactor and the fourth FCC reactor converts from 1.5 wt. % to 4.5 wt. % of the light hydrocarbon feed to coke.   
     
     
         18 . The process of  claim 17 , wherein the first FCC reactor and the second FCC reactor coverts at least 2% more of the heavy hydrocarbon feed to coke than the third FCC reactor and the fourth FCC reactor converts the light hydrocarbon feed to coke. 
     
     
         19 . The process of  claim 1 , wherein no coke precursors are introduced to the heavy hydrocarbon feed or to the light hydrocarbon feed. 
     
     
         20 . The process of  claim 1 , wherein the first FCC reactor, the second FCC reactor, the third FCC reactor, and the fourth FCC reactor are each independently operated at a temperature of greater than or equal to 580° C. a catalyst-to-oil ratio of from 3:1 to 50:1, and a residence time of from 0.1 seconds to 60 seconds.