METHOD FOR DEHYDRATING A MIXTURE CONTAINING ETHANOL AND ISOPROPANOL

摘要

The invention relates to a method for producing a mixture of ethylene and propylene from a mixture containing ethanol and isopropanol and having a water content of 30 to 75 wt % relative to the total weight of the mixture, in which: a) the mixture is placed in contact, in a dehydration unit, with a dehydration catalyst selected among: an alumina (A) having a BET specific surface, measured according to standard ASTM D 3663-03, of 200 to 350 m2/g, a mean mesoporous diameter of 5 to 15 nm, a sodium content of less than 50 ppm by weight and a sulphur content of less than 40 ppm by weight; and an alumina (B) having a BET specific surface, measured according to standard ASTM D 3663-03, of 130 to 180 m2/g, a mean mesoporous diameter of 14 to 20 nm, a sodium content of 300 to 600 ppm by weight and a sulphur content of 800 to 1300 ppm by weight; the contact being carried out at a temperature of 350 to 500 °C, at a total pressure of 0.2 to 2 MPa and with an hourly weighted speed (pph), defined as being the ratio of the mass flow of ethanol and isopropanol to the weight of the catalyst, of 1 to 10 h-1; and b) bleeding off an effluent containing ethylene and propylene from said dehydration unit.