Patent ID: 7361799

Claim:
A process for producing olefins comprising: (a) providing a vapor product stream from an oxygenate to olefin reaction comprising C 2 to C 4 olefins, C 5 + hydrocarbons, at least one oxygenate and water; (b) cooling the vapor product stream to remove water therefrom and produce a first vapor effluent stream; (c) compressing and cooling the first vapor effluent stream to produce a second effluent stream that is at least partially in the vapor state; (d) washing at least part of the second effluent stream with a liquid alcohol-containing stream to remove at least a portion of at least one oxygenate from the second effluent stream in a wash liquid effluent stream, and produce a wash vapor effluent stream comprising C 2 to C 4 olefins, the wash liquid effluent stream further comprising C 5 + hydrocarbons and alcohol contained in the liquid alcohol-containing stream; (e) contacting at least a portion of the wash liquid effluent stream with a liquid water-containing stream in a liquid-liquid contacting device to at least partially separate said wash liquid effluent stream, or portion thereof, into an aqueous phase rich in said at least one oxygenate and alcohol from the liquid alcohol-containing stream, and an organic phase rich in said C 5 + hydrocarbons; (f) washing the wash vapor effluent stream with a stream containing predominantly water to form a water-washed vapor effluent stream and a water-washed liquid effluent stream; (g) treating the water-washed vapor effluent stream with a basic component to remove carbon dioxide therefrom, thus forming a CO 2 -depleted, water-washed vapor effluent stream; and (h) cooling the CO 2 -depleted, water-washed vapor effluent stream to a temperature below 90° F. (32° C.) and separating the cooled, CO 2 -depleted, water-washed vapor effluent stream into a partially dried vapor stream containing light olefins and a wet liquid stream.