| 主权项 |
1. A process for the preparation of an olefinic product comprising ethylene and/or propylene from an oxygenate, the process comprising the following steps:
a) contacting the oxygenate in an oxygenate conversion reaction zone with a molecular sieve-comprising catalyst at a temperature in the range of from 350 to 1000° C. to produce an oxygenate conversion effluent comprising olefins, water, carbon dioxide and carbonyl compounds including C2+ aldehyde and/or ketone; b) separating water from the oxygenate conversion effluent to obtain a water-depleted gaseous oxygenate conversion effluent comprising olefins, carbon dioxide and C2+ aldehyde and/or ketone; c) compressing the water-depleted gaseous effluent with the optional removal of any condensed phase to obtain a compressed gaseous stream comprising olefins, carbon dioxide and C2+ aldehyde and/or ketone; d) separating carbon dioxide from the compressed gaseous stream by subjecting the compressed gaseous stream to a caustic wash treatment in a caustic tower wherein the gaseous stream is countercurrently contacted with a caustic solution to obtain a washed gaseous stream comprising olefins; and e) subjecting the washed gaseous stream to one or more separation steps such that at least an olefin product stream comprising ethylene and/or propylene is obtained, wherein in step d) a non-aqueous liquid stream comprising one or more aromatic C7+ hydrocarbons is added to the caustic solution prior to contacting the caustic solution with the gaseous stream and wherein a liquid phase comprising spent caustic solution and the one or more aromatic C7+ hydrocarbons is discharged from the caustic tower and wherein the non-aqueous liquid stream comprises less than 0.1 wt % of olefinic hydrocarbons and at least part of the non-aqueous liquid stream comprising one or more aromatic C7+ hydrocarbons is recovered from the oxygenate conversion effluent in step b), step c), and/or step e). |
