Mobil Oil Corporation

Other

Diane V Jorgensen

Ajit V Sapre

David L Johnson

Stephen S Wong

Clinton R Kennedy

Lloyd L Breckenridge

An FCC process and apparatus operates with closed reactor cyclones and a catalyst stripper using H2 or recycled stripper vapor for stripping gas. Preferably stripper vapor is removed, cooled and condensed, and some vapor recycled to the stripper. Isolation of the stripper from the cracked product vapors permits use of large amounts of stripping steam, or stripping gases such as hydrogen.

FCC catalyst stripping with vapor recycle

Catalyst stripping in the fluid catalytic cracking process is improved by cooling the spent catalyst to quench catalytic condensation reactions, then stripping the cooled catalyst in a primary stripper, followed by heating and a stage of hot stripping. Quenched stripping reduces coke make by reducing conversion of light olefins, made during the FCC process, into coke.

Quenched multistage FCC catalyst stripping

A process for reducing the benzene content of a reformate stream in a conventional catalytic cracking reactor wherein a heavy hydrocarbon feed is cracked to lighter products by contact with a supply of hot regenerated cracking catalyst is disclosed. The reformate can be mixed with the heavy feed to the cracking reactor, but preferably reformate contacts hot regenerated cracking catalyst before the heavy feed is added. Benzene content is reduced by alkylation with reactive fragments created in the cracking reactor, or by transalkylation with alkyl aromatics. Benzene removal can be enhanced by adding a light reactive gas such as ethylene to the cracking reactor, by adding heavier aromatics, such as a light cycle oil, or both. The reaction is preferably conducted in an FCC riser reactor, but may be conducted in a moving bed cracking reactor.

Reduction of benzene content of reformate in a catalytic cracking unit

Conversion of benzene to heavier aromatics by contact with alkyl polynucleararomatics, preferably FCC heavy cycle oil, in the presence of an alkylation/transalkylation catalyst is disclosed. Efficient conversion of relatively dilute benzene in reformate is possible. Use of alkyl polynucleararomatics as a source of alkyl groups, with reduced use of monocyclic alkyl aromatics, permits robust reaction conditions to be used without a net formation of benzene by dealkylation. The process preferably uses a solid zeolite based acidic catalyst disposed in a fixed, moving or fluid bed reactor. Preferred catalysts comprise MCM-22 or ZSM-5.

Reduction of benzene content of reformate by reaction with cycle oils

A process is described which improves the performance of cyclic dewaxing/regeneration processes using a catalyst comprising palladium and a zeolite having the structure of Zeolite Beta. The cyclic process includes regenerating the catalyst by oxidation alone or combinations of oxidation and reduction to substantially restore catalyst activity.

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Wilmington, DE, United States of America

Diane V Jorgensen