Patent ID: 7090081
Filing Date: 2006-08-15
Classification: B01J,C07C,C10G,Y02P

Abstract:
1. A process for selectively removing large catalyst particles from a reaction system, wherein the reaction system comprises a reaction zone and a disengaging zone, the process comprising the steps of: (a) feeding a plurality of catalyst particles into the reaction zone, wherein the plurality of catalyst particles comprises a molecular sieve selected from the group consisting of SAPO-5, SAPO-8, SAPO-11, SAPO-16, SAPO-17, SAPO-18, SAPO-20, SAPO-31, SAPO-34, SAPO-35, SAPO-36, SAPO-37, SAPO-40, SAPO-41, SAPO-42, SAPO-44, SAPO-47, SAPO-56, AEI/CHA intergrowths, metal containing forms thereof, intergrown forms thereof, and mixtures thereof; (b) contacting the plurality of catalyst particles with a feedstock comprising an oxygenate in the reaction zone under conditions effective to convert at least a portion of the feedstock to product comprising light olefins; (c) separating a portion of the catalyst particles from the product in a disengaging zone; (d) directing a portion of the plurality of catalyst particles separated in the disengaging zone to a counter-flow cyclone separator, wherein the portion of the plurality of catalyst particles has a first median particle diameter; (e) separating the portion of the plurality of catalyst particles in the counter-flow cyclone separator into a small catalyst stream and a large catalyst stream by modulating flow rate of a gas stream to the cyclone separator to control particle size of the catalyst streams, wherein the small catalyst stream has a second median particle diameter less than the first median particle diameter; and (f) directing at least a portion of the small catalyst stream to the reaction system.