Underflow cyclones and FCC process

摘要

A "leaking" cyclone and process for fluidized catalytic cracking of heavy oils is disclosed. Gas and entrained solids are added tangentially to swirl around a vapor outlet tube in a cylindrical tube cyclone body. A concentrated stream of solids and some gas is withdrawn from the device through openings in the cylindrical sidewall remote from the inlet. Tangential withdrawal via an offset slit in the sidewall, or withdrawal through holes in the sidewall, replaces or reduces conventional underflow of solids from an end of the cyclone body. Fine (0-5 micron) particles removal is enhanced by withdrawing solids as soon as solids reach the cylindrical sidewall. The device may be used as a third stage separator on an FCC regenerator.