Abstract: A method for maintaining the activity of silicoaluminophosphate (SAPO) molecular sieve catalyst particles during oxygenate to olefin conversion reactions. The SAPO catalyst particles are regenerated under targeted conditions in the presence of platinum to provide controlled, steady state regeneration while minimizing catalyst damage.

Abstract: This invention is directed to methods of converting oxygenates to olefin products. The methods provided include steps for protecting against deactivation of active molecular sieve catalysts during the conversion process. In particular, the invention provides for methods of regenerating coked catalyst to minimize catalyst deactivation due to contact with moisture.

Abstract: A multi-stage gas-solids separator is configured so that the higher density (solids) output flows of two or more of the separator stages are merged together. The multi-stage separator is preferably composed of cyclone separators, with the diplegs of at least two of the cyclone separator stages merged together.

Abstract: This invention provides processes for maintaining a desired particle size distribution in an oxygenate to olefin reaction system. In one embodiment, the invention comprises replacing lost catalyst fines with less active co-catalyst particles. By adding less active co-catalyst particles to the reaction system, desirable fluidization characteristics and hydrodynamics can be maintained without affecting the overall (or primary catalyst) performance and product selectivities. The invention is also directed to a population of catalyst particles having a desirable particle size distribution well-suited for realizing ideal fluidization and hydrodynamic characteristics.