Method and apparatus for removing small catalyst particles in fcc systems

Abstract

Disclosed is a method of and apparatus for reducing the level of extremely small catalyst particles ('fines') in an FCC system by temporarily retaining particles separated from the secondary cyclone separator in either a reactor vessel or catalyst regenerator. These particles can be withdrawn from the temporary retaining area, which takes them out of the active catalyst inventory within the reactor/regenerator system. The withdrawing of catalyst 'fines' reduces the particulate contamination both in flue gas exhausted to the atmosphere from the catalyst regenerator and in the main column bottom (MCB) products from the fractionation stage. Preferred embodiments includes withdrawal of 'fines' from either the regenerator or the reactor vessels and the secondary cyclones contained in each of these vessels.