Patent ID: 7317133

Claim:
A process for the production of light weight olefins comprising: a) producing an olefin-rich feedstock by contacting an oxygenate-containing feedstock with a catalyst comprising a non-zeolitic molecular sieve; b) passing the olefin-rich feedstock comprising C 2 to C 8 olefins to a first stage separation zone to provide a light weight olefin stream comprising C 2 to C 3 olefins and a heavy weight olefin stream comprising C 4 + olefins; c) passing the heavy weight olefin stream to a second stage separation zone to provide a second light weight olefin stream, a medium weight olefin stream comprising C 4 to C 7 olefins, and a C 7 + olefin stream; d) passing the medium weight olefin stream to an olefin cracking reactor operated at an inlet temperature of about 450° to 600° C. to convert at least a portion of the medium weight olefin stream into a cracked olefin stream comprising C 2 to C 3 olefins wherein said medium weight olefin stream contacts a catalyst comprising a crystalline silicate of the MFI family or the MEL family; e) returning at least a portion of the cracked olefin stream to the second stage separation zone, withdrawing a drag stream comprising the remaining portion of the cracked olefin stream; and f) returning at least a portion of the second light weight olefin stream to the first separation zone.