Patent ID: 8692045

Claim:
A process for producing light olefins, comprising the following steps in sequence: contacting, in a pre-reaction zone, a feedstock with a catalyst comprising at least one silicon-aluminophosphate molecular sieve to produce a gas-phase stream; passing the gas-phase stream and the catalyst into at least one riser; passing the gas-phase stream and the catalyst through an outlet of the at least one riser into a gas-solid rapid separation zone to separate therein the gas-phase stream and the catalyst; passing the separated gas-phase stream into a separation section; returning a first portion of the separated catalyst to the pre-reaction zone, and regenerating a second portion of the separated catalyst in a regenerator; wherein an inlet of the at least one riser extends into the pre-reaction zone, about 60% to about 90% of the height of the at least one riser is within a heat exchange zone, the outlet of the at least one riser extends into the gas-solid rapid separation zone, and the average temperature in the at least one riser is higher than the average temperature in the pre-reaction zone.