Process for producing light olefins from methanol or dimethyl ether

A process for producing light olefins from methanol and/or dimethyl ether comprising the steps of:

• (a) introducing a feed comprising methanol and/or dimethyl ether into a fluidized-bed reactor from its bottom, and reacting the feed in a dense phase zone and a transition zone of the fluidized-bed reactor by contacting it with a catalyst, to form an effluent I comprising unreacted feed, reaction products and entrained solid particulate catalyst;
• (b) introducing a terminating agent at a lower portion of a gas-solid separating zone of the fluidized-bed reactor into the effluent I, to give an effluent II, wherein the terminating agent is at least one selected from the group consisting of water, C2 to C5 alcohols, C2 to C10 ethers, hydrocarbons having 4 or more carbon atoms, and C6 to C12 aromatic hydrocarbons;
• and
• (c) passing the effluent II into the gas-solid separating zone in upper portion of the fluidized-bed reactor, where gas-solid separation is accomplished to give a gaseous product stream and solid catalyst, said gaseous product stream being led to an after-treatment stage, and said solid catalyst being circulated to the dense phase zone in lower portion of the fluidized-bed reactor or, alternatively, being led to a regenerator after having been stripped in a stripper wherein the effluent II passed into the gas-solid separating zone is first passed through a whirl-flow quickly-separating unit to separate out most of the entrained solid particulate catalyst, and a resultant gaseous stream III containing the remaining entrained particulate catalyst is led into a outside-type cyclone and is separated there into a particulate catalyst stream and the gaseous product stream.