Patent ID: 6951968
Filing Date: 2005-10-04
Classification: C10G

Abstract:
1. A process for the production of olefins by catalytic cracking, the process comprising feeding a hydrocarbon feedstock containing at least one olefin of C 4 or greater over an MFI crystalline silicate catalyst to produce an effluent containing at least one olefin of C 2 or greater by catalytic cracking which is selective towards light olefins in the effluent, whereby for increasing the catalyst stability by limiting formation of coke thereon during the cracking process the catalyst has a silicon/aluminum atomic ratio of from 300 to 1000, the olefin partial pressure is from 0.1 to 2 bars, and the feedstock contacts the catalyst at an inlet temperature of from 500 to 600° C., wherein the catalyst has been pretreated by heating the catalyst in steam to reduce the tetrahedral aluminum in the crystalline silicate framework of said catalyst and convert the tetrahedral aluminum to octahedral aluminum in the form of amorphous alumina causing partial obstruction in the pores of said crystalline silicate framework and thereafter dealuminating the catalyst by treating the catalyst with a complexing agent for aluminum to remove amorphous alumina from the pores of said crystalline silicate framework and at least partially recover the micropore volume to increase the silicon/aluminum atomic ratio of the catalyst to a value of from 300 to 1000.