Process for dehydration of dilute ethanol into ethylene with low energy consumption without recycling of water

摘要

A process for dehydration of an ethanol feedstock into ethylene, comprising the vaporization of said dilute hydrated ethanol feedstock in an exchanger, with heat exchange with the effluent that is obtained from a last reactor, with said mixture being introduced into said vaporization stage at a pressure that is lower than the pressure of the effluent that is obtained from the last reactor, the compression of the mixture that is vaporized in a compressor, the introduction of the vaporized and compressed mixture, into at least one adiabatic reactor that contains at least one dehydration catalyst.

主权项

1. A process for dehydration of an ethanol feedstock, comprising ethanol of between 2 and 55% by weight, into ethylene comprising:
a) vaporizing dilute ethanol feedstock in an exchanger, said exchanger exchanging heat with effluent that is obtained from a last adiabatic reactor, said dilute ethanol feedstock being introduced into said exchanger at a pressure that is lower than that of the effluent that is obtained from the last reactor, b) compressing vaporized dilute ethanol feedstock in a compressor, c) introducing vaporized and compressed feedstock, at an entrance temperature of between 350 and 550° C. and at an entrance pressure of between 0.3 and 1.8 MPa, in at least one adiabatic reactor that contains at least one dehydration catalyst and in which the dehydration reaction takes place, d) separating effluent that is obtained from a last adiabatic reactor of c) into an effluent that comprises ethylene at a pressure that is lower than 1.6 MPa and an effluent that comprises water, e) purifying at least a portion of the effluent that comprises water that is obtained from d) and separating at least one stream of unconverted ethanol, with no recycling upstream from a) of purified water that is obtained from e).