Appeal No. 2005-0183
Application No. 09/206,218
APPENDIX
1. A process for the production of olefins by catalytic
cracking, the process comprising feeding a hydrocarbon feedstock
containing at least one olefin of C4 or greater over an MFI
crystalline silicate catalyst to produce an effluent containing
at least one olefin of C2 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
600BC, 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.
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