Patent ID: 8148587
Filing Date: 2012-04-03
Classification: C07C,Y02P

Abstract:
1. A method for converting methanol or/and dimethyl ether into light olefins, characterized in that at least three independent reaction zones and at least one separation zone are employed, wherein all feedstock of methanol or/and dimethyl ether is divided to be fed at said three independent reaction zones, and the distribution of the olefins in the final product can be adjusted by changing the feeding proportion for each reaction zone, the method comprising the steps of: (a) transforming methanol or/and dimethyl ether into a mixed stream of hydrocarbons that contains ethylene, propylene and olefins with 4 and more carbon atoms in the presence of acidic catalyst(s) in the first reaction zone, and feeding said stream directly into said separation zone; (b) separating the streams flowing out of said three reaction zones in said separation zone, the effluent of C3 fractions flowing out of said separation zone and forming a propylene product upon a further separation, at least a portion of the effluent of fractions with no more than 2 carbon atoms entering into the second reaction zone and the rest being further separated to obtain an ethylene product, and at least a portion of the effluent of fractions with 4 or more carbon atoms entering into the third reaction zone and the rest being further separated to obtain a butylene product; (c) contacting the methanol or/and dimethyl ether together with at least a portion of the fractions that come from said separation zone and contain no more than 2 carbon atoms with acidic catalyst(s) in the second reaction zone, and feeding the resultant mixed materials containing propylene directly into said separation zone; and (d) contacting methanol or/and dimethyl ether together with at least a portion of the fractions that come from said separation zone and contain 4 or more carbon atoms with acidic catalyst(s) in the third reaction zone, and feeding the resultant mixed materials containing ethylene and propylene directly into said separation zone.