Process for catalytic cracking a fischer-tropsch derived feedstock with heat balanced operation of the catalytic cracking system

Abstract

A catalytic cracking process that processes a Fischer-Tropsch derived waxy feedstock and which is operated in a heat balanced mode without the use of additional heat sources or heavy feedstock. Heat is provided by the coke yielded from cracking of the Fischer-Tropsch derived waxy feedstock. A combination of the use of a high rare earth oxide large pore zeolite cracking catalyst with the operation of the riser reactor under suitable cracking conditions provide a spent cracking catalyst having a coke content sufficient to provide for the heat balance in the operation of the catalytic cracking system.

1 . A catalytic cracking process, which comprises:
 providing a catalytic cracking system, wherein said catalytic cracking system comprises a riser reactor, a separator and a regenerator each thereof being operatively interconnected;   introducing a cracking catalyst, wherein said cracking catalyst comprises a large pore zeolite having a rare earth component present in said large pore zeolite in an amount in the range of from 0.25 to 5 weight percent (wt. %), based on the weight of said large pore zeolite, into a riser reactor zone defined by said riser reactor;   introducing a hydrocarbon feedstock, wherein said hydrocarbon feedstock comprises a Fischer-Tropsch derived waxy feedstock, into said riser reactor zone operated under suitable catalytic cracking conditions, wherein said cracking catalyst is contacted and mixed with said hydrocarbon feedstock;   passing from said riser reactor zone a riser reactor product mixture, wherein said riser reactor product mixture comprises a cracked hydrocarbon product and a spent cracking catalyst having coke deposited thereon in an amount or at a concentration sufficient to provide for the heat balance in the operation of said catalytic cracking system of said catalytic cracking process by combustion of said coke within said regenerator;   introducing said riser reactor product mixture into a separation zone defined by said separator providing for the separation of said riser reactor product mixture into a separated cracked hydrocarbon product and a separated spent cracking catalyst;   passing said separated spent cracking catalyst to a regeneration zone defined by said regenerator wherein said coke on said separated spent cracking catalyst is combusted so as to release heat energy and to provide a regenerated cracking catalyst; and   utilizing said regenerated cracking catalyst as said cracking catalyst.   
     
     
         2 . A catalytic cracking process as recited in  claim 1 , wherein said hydrocarbon feedstock further comprises a material absence of a hydrocarbon source other than said Fischer-Tropsch derived waxy feedstock. 
     
     
         3 . A catalytic cracking process as recited in  claim 2 , further comprising:
 introducing into said riser reactor zone as an additive with said cracking catalyst a minor amount of a shape selective zeolite additive.   
     
     
         4 . A catalytic cracking process as recited in  claim 3 , wherein said suitable catalytic cracking conditions include a gas residence time in the range of from 1 second to 10 seconds, a riser reactor temperature greater than 500° C., and a catalyst-to-oil ratio greater than 8. 
     
     
         5 . A catalytic cracking process as recited in  claim 4 , wherein said cracking catalyst further comprises a matrix or binder component and an amount of said large pore zeolite greater than 50 weight percent (wt. %), based on the weight of said cracking catalyst. 
     
     
         6 . A catalytic cracking process as recited in  claim 5 , further comprising: introducing no material amount of said hydrocarbon source other than said Fischer-Tropsch derived waxy feedstock into said riser reactor zone. 
     
     
         7 . A catalytic cracking process as recited in  claim 6 , further comprising: introducing no material amount of an additional hydrocarbon source into said regeneration zone other than hydrocarbon that is contained on said separated spent cracking catalyst for the purpose of generating heat energy.