Fluid catalytic cracking process including flue gas conversion process

Abstract

A method is provided to reduce carbon dioxide emissions and increase the output of more valuable hydrocarbon products in a fluid catalytic cracking unit.

1 . A fluid catalytic cracking process, comprising the steps of:
 feeding a high molecular weight hydrocarbon feedstock into a reactor;   mixing the feedstock with catalyst and cracking and vaporizing the feedstock within the reactor;   recycling spent, catalyst from the reactor to a regenerator;   burning off coke from the spent catalyst within the regenerator to regenerate the spent catalyst, producing flue gases including CO and CO 2  which leave the regenerator through a flue;   returning the regenerated catalyst back to the reactor;   feeding at least some of the flue gases from the regenerator to a flue gas conversion plant;   reacting CO in the flue gases with hydrogen and producing hydrocarbon products using a Fischer-Tropsch process in said flue gas conversion plant; and   recycling CO 2  from the flue gases back to the regenerator.   
     
     
         2 . A fluid catalytic cracking process as recited in  claim 1 , wherein coke on the spent catalyst is a first carbon source product fed into the regenerator and further comprising the step of injecting an additional carbon source product into the regenerator. 
     
     
         3 . A fluid catalytic cracking process recited in  claim 2 , and further comprising the steps of:
 sending the product from the reactor to a main fractionator;   separating the product in the fractionator by means of distillation, and   sending some of the fraction produced by the fractionator to the regenerator to serve as at least some of said additional carbon source injected into the regenerator.   
     
     
         4 . A fluid catalytic cracking process as recited in  claim 3 , and further comprising the steps of:
 sending at least a portion of the off-gas from said main fractionator to the flue gas conversion plant and using, that portion of the off-gas as a so of hydrogen for the Fischer-Tropsch process.   
     
     
         5 . A fluid catalytic cracking process as recited in  claim 4 , and further comprising the step of sending said hydrocarbon products produced by the Fischer-Tropsch process to the main fractionator of the fluid catalytic cracking unit. 
     
     
         6 . A fluid catalytic cracking process as recited in  claim 1 , including the step of recycling said CO 2  to drive the net production of CO 2  in the regenerator to extinction. 
     
     
         7 . A fluid catalytic cracking process as recited in,  claim 1 , wherein said hydrogen is imported into the fluid catalytic cracking unit. 
     
     
         8 . A fluid catalytic cracking process as recited in  claim 1 , wherein said hydrogen is generated electrolytically. 
     
     
         9 . A fluid catalytic cracking process as recited in  claim 3 , and further comprising the step of using natural gas to generate hydrogen for the Fischer-Tropsch process. 
     
     
         10 . A fluid catalytic cracking process as recited in  claim 4 , wherein some of said additional carbon source injected into the regenerator is the bottoms from the fractionator. 
     
     
         11 . A fluid catalytic cracking process as recited in  claim 1 , including the step of recycling enough CO 2  from the flue gases back to the regenerator to drive the net production of CO 2  in the regenerator to extinction. 
     
     
         12 . A fluid catalytic cracking process as recited in  claim 11 , wherein said feedstock is a high residue feedstock containing up to 10% Conradson carbon, and further comprising the steps of:
 injecting oxygen into the regenerator; and   diluting said oxygen with the recycled CO 2  from the flue gases.   
     
     
         13 . A fluid catalytic cracking process as recited in  claim 1 , wherein said Fischer-Tropsch process produces waste heat, and further comprising the step of using at least some of the waste heat produced by the Fischer-Tropsch process to drive a compressor in the flue gas conversion plant. 
     
     
         14 . A fluid catalytic cracking process as recited in  claim 13  including the step of using said waste heat to produce steam and using the steam to drive the compressor. 
     
     
         15 . A fluid catalytic cracking process as recited in  claim 13 , including the step of using said waste heat to generate electricity and using electricity generated from the waste heat to drive the compressor. 
     
     
         16 . A fluid catalytic cracking process, comprising the steps of:
 feeding a high molecular weight hydrocarbon feedstock into a reactor;   mixing the feedstock with catalyst and cracking and vaporizing the feedstock within the reactor;   recycling spent catalyst from the reactor to a regenerator;   burning off coke from the spent catalyst within the regenerator to regenerate the spent catalyst, producing flue gases including CO and CO 2 , which leave the regenerator through a flue;   returning the regenerated catalyst hack to the reactor;   feeding at least some of the flue gases from the regenerator to flue gas conversion plant;   reacting CO in the flue gases with hydrogen and producing hydrocarbon products using a Fischer-Tropsch process in said flue gas conversion plant, wherein said Fischer-Tropsch process produces waste heat; and   using at least some of the waste heat produced by the Fischer-Tropsch process to drive a compressor in the flue gas conversion plant.   
     
     
         17 . A fluid catalytic cracking process as recited in  claim 16 , including the step of using said waste heat to produce steam and using the steam to drive the compressor. 
     
     
         18 . A fluid catalytic cracking process as recited in  claim 17 , including the step of using said waste heat to generate electricity and using electricity generated from the waste heat to drive the compressor.