Abstract:
The invention relates to process for the preparation of an olefinic product comprising ethylene and/or propylene from an oxygenate, the process comprising the following steps: a) an oxygenate conversion step wherein a gaseous effluent comprising olefins and a water-soluble oxygenate is obtained; b) separation of water from the effluent; c) compression of the effluent; d) acid gas removal from the compressed gaseous effluent obtained in step c), wherein the compressed gaseous effluent is treated with a caustic solution in a caustic tower; and e) separating the olefinic product from the gaseous effluent treated in step d), wherein, in a final stage in the caustic tower, water-depleted compressed gaseous effluent is treated with a water stream that is essentially free of water-soluble oxygenate and a spent water stream comprising caustic and water-soluble oxygenate is obtained, which spent water stream is withdrawn from the process.
Abstract:
The invention provides a process for the preparation of an olefinic product, the process comprising the steps of: (a) reacting an oxygenate feedstock, comprising oxygenate, in an oxygenate reaction zone in the presence of a catalyst comprising a molecular sieve, at a temperature in the range of from 350 to 1000° C., to produce a reaction effluent stream, comprising at least oxygenate, olefin, water and acidic by-products; (b) cooling the reaction effluent stream by means of an indirect heat exchange to provide a cooled reaction effluent stream at a temperature greater than the dew point temperature of reaction effluent stream; (c) passing the cooled reaction effluent stream into a quench tower and contacting the cooled reaction effluent stream with a first aqueous liquid in the presence of at least one set of quench tower internals, to produce a quench tower gaseous stream comprising the olefinic product and a quench tower liquid stream comprising condensed material; and (d) separating the quench tower liquid stream into a hydrocarbon quench tower liquid stream and an aqueous quench tower liquid stream in the presence of one or more coalescers.