Exxon Research and Engineering Company

Exxonmobil Chemical Patents Inc.

George Melfi

Robert F Tammera

Donald F Shaw

Kenneth J Reinman

Paul K Ladwig

Todd R Steffens

John E Asplin

The invention relates to a process for maintaining heat balance in a fluidized bed catalytic cracking unit. More specifically, the invention relates to a combustion control method capable of maintaining or restoring heat balance by conducting, under appropriate conditions, fuel and an oxygen-containing gas to a transfer line. The transfer line conducts effluent including spent catalyst and combustion products to the unit's catalyst regeneration zone.

Method for maintaining heat balance in a fluidized bed catalytic cracking unit

Accordingly, the present invention, in one embodiment, encompasses an apparatus for the fluidized catalytic cracking of a hydrocarbon feed comprising: a riser which is generally vertically positioned within a catalyst disengaging zone and which has a plurality of openings around the circumference of the riser at its discharge end. The openings in the riser have a vertical stub portion that extends tangentially outwardly from the riser and communicates with a first end of an upwardly sloping curvilinear tunnel that terminates at a second end. The second end of the tunnel opens into a tangential opening in the primary cyclone. The area of the opening of the first end of the tunnel is larger than the area of the opening of the second end of the tunnel.

Improved method for transferring entrained solids to a cyclone

Tangential solids separation transfer tunnel

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Whippany, NJ, United States of America

George Melfi