Process for dehydration of ethanol into ethylene with low energy consumption

摘要

A process for dehydration of an ethanol feedstock into ethylene, comprising the vaporization of said ethanol feedstock in a mixture with at least a portion of the recycled purified water stream from heat exchange with the effluent that is obtained from the last reactor.

主权项

1. A process for dehydration of an ethanol feedstock into ethylene comprising:
a) vaporizing of said ethanol feedstock in a mixture with at least a portion of a purified water stream recycled from f) in an exchanger owing to a heat exchange with the effluent that is obtained from a last adiabatic reactor, introducing said ethanol feedstock in a mixture with at least a portion of said purified water stream that is recycled into said vaporization at a pressure of between 0.1 and 0.4 MPa, b) compressing vaporized ethanol feedstock purified water mixture, in a compressor, c) introducing compressed vaporized ethanol feedstock purified water mixture, at an entrance temperature of between 350 and 500° C. and at an entrance pressure of between 0.2 and 1.3 MPa, in at least one adiabatic reactor that contains at least one dehydration catalyst and in which dehydration reaction takes place, d) separating effluent that is obtained from a last adiabatic reactor of stage c) in an effluent that comprises ethylene an effluent that comprises water, wherein the effluent that comprises ethylene is at a pressure that is lower than 1 MPa, e) purifying at least a portion of the effluent comprising water that is obtained from d) and separating at least one purified water stream and at least one unconverted ethanol stream, f) recycling at least a portion of the purified water stream that is obtained from e), upstream from a).