Patent ID: 7919660

Claim:
A method of converting methanol feedstock to olefins comprising: contacting the methanol feedstock in a first conversion zone with a catalyst at reaction conditions effective to produce a first reaction zone effluent comprising DME, unreacted methanol and water; cooling the first reaction zone effluent to separate DME as a first vapor product from the first reaction zone effluent and to form a first aqueous stream comprising water, unreacted methanol, soluble DME and oxygenates; contacting the first vapor product in a second conversion zone with a catalyst at reaction conditions effective to produce a second reaction zone effluent comprising light olefins, unreacted DME, water and oxygenates; cooling the second reaction zone effluent to separate the light olefins and the unreacted DME as a second vapor product from the second reaction zone effluent and to form a second aqueous stream comprising water, soluble DME and oxygenates; compressing the unreacted DME and the light olefins; separating DME from the light olefins with an aqueous absorbing liquid to produce substantially DME free olefins product and a third aqueous stream comprising the absorbing liquid, absorbed DME, soluble oxygenates and hydrocarbons; feeding at least a portion of the first, second and/or third aqueous streams into a stripper and stripping out and recovering the methanol, DME, soluble oxygenates and hydrocarbons as an overhead vapor product and a fourth aqueous stream comprising substantially clean water as a bottoms liquid product; and recycling at least a portion of the overhead vapor product to the first conversion zone and/or to the second conversion zone.