Process for fluid catalytic cracking of heavy oil

Abstract

Provided is a process for fluid catalytic cracking of a heavy oil by contacting the oil with a catalyst at an elevated temperature for a short period of time to produce light olefins such as propylene and butene. The process comprises contacting the heavy oil with a catalyst containing 12 to 24 percent by mass of a shape selective zeolite under conditions of a reaction zone outlet temperature of 580 to 630° C., a catalyst/oil ratio of 15 to 40 weight/weight and a hydrocarbon residence time in the reaction zone of 0.1 to 1.0 second to produce a cracked product having a secondary cracking activity (C2 olefin concentration/C4 olefin concentration) value in the range of 0.30 to 0.55.

1 . A process for fluid catalytic cracking of a heavy oil to produce light olefins, comprising contacting the heavy oil with a catalyst containing 12 to 24 percent by mass of a shape selective zeolite under conditions of a reaction zone outlet temperature of 580 to 630° C., a catalyst/oil ratio of 15 to 40 weight/weight and a hydrocarbon residence time in the reaction zone of 0.1 to 1.0 second to produce a cracked product having a secondary cracking activity (C2 olefin concentration/C4 olefin concentration) value in the range of 0.30 to 0.55. 
     
     
         2 . The process for fluid catalytic cracking of a heavy oil according to  claim 1  wherein the catalyst comprises a fluid catalytic cracking catalyst and an additive comprising the shape selective zeolite, and the fluid catalytic cracking catalyst contains 5 to 50 percent by mass of an ultrastable Y type zeolite. 
     
     
         3 . The process for fluid catalytic cracking of a heavy oil according to  claim 1  wherein the catalyst comprises a fluid catalytic cracking catalyst and an additive comprising the shape selective zeolite, and the additive contains 20 to 70 percent by mass of the shape selective zeolite. 
     
     
         4 . The process for fluid catalytic cracking of a heavy oil according to  claim 1  wherein the catalyst comprises a fluid catalytic cracking catalyst and an additive comprising the shape selective zeolite, and the catalyst contains the additive in an amount of 17 to 60 percent by mass. 
     
     
         5 . The process for fluid-catalytic cracking of a heavy oil according to  claim 2  wherein the ultrastable Y type zeolite has a crystal lattice constant of 24.20 to 24.60 Å. 
     
     
         6 . The process for fluid-catalytic cracking of a heavy oil according to  claim 1  wherein the catalyst comprises a fluid catalytic cracking catalyst and an additive comprising the shape selective zeolite and the fluid catalytic cracking catalyst contains a rare-earth metal oxide in an amount of 1.5 percent by mass or less. 
     
     
         7 . The process for fluid-catalytic cracking of a heavy oil according to  claim 1  wherein a fluid catalytic cracking reactor having a downflow type reaction zone, a gas-solid separation zone, a stripping zone and a catalyst regeneration zone is used.