PRODUCTION OF LOWER OLEFIN

The invention relates to a process for the production of lower olefins from methanol by reaction of a reaction mixture containing methanol and/or dimethyl ether vapour and water vapour in a tubular reactor over an indirectly cooled catalyst based on crystalline aluminosilicates of the pentasil type having an Si/Al atomic ratio of at least 10. The process is characterised in that in order to produce an olefin mixture containing at least 5% by weight of ethylene, at least 35% by weight of propylene and at most 30% by weight of butylene, relative to the entire hydrocarbons, the reaction is carried out at a total pressure of 10 to 90 kPa, at a weight ratio of water to methanol or to methanol equivalents of 0.1 to 1.5 at a temperature of the reactor cooling medium of 280 to 570 DEG C over a proton-containing catalyst of the pentasil type which has an alkali metal content of less than 380 ppm, a ZnO content of less than 0.1% by weight, a CdO content of less than 0.1% by weight, a BET surface area of 300 to 600 m /g and a pore volume (measured by mercury porosimetry) of 0.3 to 0.8 cm /g.