OXYGENATE-TO-OLEFINS PROCESS AND AN APPARATUS THEREFOR

摘要

The present invention relates to a process for the preparation of an olefinic product, such as one or both of ethylene and propylene, from an oxygenate feedstock, such as methanol, and an apparatus therefore, said process comprising: treating an effluent stream with a carbonyl compound absorbent stream comprising an aqueous solution of bisulphite having a pH in the range of from 4 to 8, to provide an olefinic product stream comprising olefin and a loaded carbonyl compound absorbent stream comprising an aqueous solution of at least one carbonyl adduct comprising one or both of C2+ aldehyde adduct and ketone adduct and optionally unreacted bisulphite, said liquid absorbent stream and loaded carbonyl compound absorbent stream in a carbonyl compound absorbent circuit separate from the effluent separation circuit.

主权项

1. A process for the preparation of olefinic product, the process comprising at least the steps of:
reacting an oxygenate feedstock comprising oxygenate in an oxygenate reaction zone in the presence of a catalyst comprising a molecular sieve to produce a reaction effluent stream comprising oxygenate, olefin, water and carbonyl compound comprising formaldehyde and one or both of C2+ aldehyde and ketone; treating the reaction effluent stream with an aqueous liquid stream to provide a water rich stream comprising oxygenate, formaldehyde and water and a water depleted effluent stream comprising olefin and carbonyl compound comprising one or both of C2+ aldehyde and ketone, said aqueous liquid stream and said water rich stream present in an effluent separation circuit; compressing the water depleted effluent stream, with the optional removal of any condensed phase, to provide a compressed effluent stream; and treating the compressed effluent stream with a carbonyl compound absorbent stream comprising an aqueous solution of bisulphite having a pH in the range of from 4 to 8, to provide an olefinic product stream comprising olefin and a loaded carbonyl compound absorbent stream comprising an aqueous solution of at least one carbonyl adduct comprising one or both of C2+ aldehyde adduct and ketone adduct and optionally unreacted bisulphite, said carbonyl compound absorbent stream and said loaded carbonyl compound absorbent stream in a carbonyl compound absorbent circuit separate from the effluent separation circuit.