Patent ID: 6455750
Filing Date: 2002-09-24
Classification: C10G

Abstract:
A catalytic conversion process comprising:contacting a thermally or catalytically cracked naphtha, the naphtha containing about 10 to about 30 wt. % paraffins, and from about 20 to about 70 wt. % olefins, with a catalytically effective amount of a catalyst in a fluidized bed reactor, wherein the catalyst contains 20 to about 60 wt. % of a ZSM-5 molecular sieve having an average pore diameter less than about 0.7 nm, wherein the catalyst's Steam Activation Index is greater than 0.75, under catalytic conversion conditions including a temperature of about 525Â° C. to about 650Â° C., a hydrocarbon partial pressure of about 10 to about 40 psia, a hydrocarbon residence time of about 1 to about 10 seconds, and a catalyst to naphtha weight ratio of about 2 to about 10, in order to form a product having a weight ratio of propylene to ethylene which is greater than about 3, with no more than about 20 wt. % of the paraffins being converted to light olefins, further provided that i) the naphtha contains C5+ olefins, and at least about 60 wt. % of the C5+ olefins in the naphtha are converted to species having a molecular weight lower than C4, ii) less than 25 wt. % of the paraffins in the naphtha are converted to species having a molecular weight lower than C4, iii) the product contains a C3 fraction with propylene comprising at least about 90 mol. % of the C3 fraction, and iv) the product contains a C2 fraction with ethylene comprising at least about 90 mol. % of the C2 fraction.