| 摘要 |
A process for catalytically cracking a heavy feed in an FCC unit, with large amounts of shape selective cracking additive is disclosed. The catalyst inventory preferably contains at least 10 wt % additive, of 12-40% ZSM-5 on an amorphous support, equivalent to more than 3.0 wt % ZSM-5 crystal circulating with equilibrium catalyst. Large yields of light olefins are produced, without excessive production of aromatics, or loss of gasoline yield. Operating with large amounts of additives allows yields of butadiene and/or methane to be suppressed, and production of a cracked gasoline fraction with an unusually low olefin content, and high ratio of cyclic unsaturates to normal unsaturates.
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