Patent ID: 8178060

Claim:
A system for converting oxygenates to light olefins, said system comprising: an oxygenate conversion reactor for contacting an oxygenate-containing feedstream with an oxygenate conversion catalyst and converting the oxygenate-containing feedstream to an oxygenate conversion product stream comprising fuel gas hydrocarbons, light olefins, and C 4+ hydrocarbons; a gas processing system effective to separate at least a portion of the oxygenate conversion product stream and form a material feedstream comprising olefins; a dividing wall fractionation column for fractionating the material feedstream comprising the C 4+ hydrocarbon stream and at least a portion of the cracked olefin effluent stream to form first hydrocarbon fraction process stream containing C 3− hydrocarbons, a second hydrocarbon fraction process stream containing C 6+ hydrocarbons, and a third hydrocarbon fraction process stream containing C 4 and C 5 hydrocarbons including C 4 and C 5 olefins; and an olefin cracking reactor for contacting at least a portion of the third hydrocarbon stream with olefin cracking catalyst and converting C 4 and C 5 olefins therein contained to a cracked olefin effluent stream comprising light olefins; and wherein the third hydrocarbon fraction process stream is the fractionated portion of the C 4+ hydrocarbon stream contacted in the olefin cracking reactor.