Patent ID: 9663414
Date: 2017-05-30
CPC Classifications: C07C,Y02P

Claim:
1. A process for dehydrating an ethanol feedstock to ethylene comprising: a) a step of preheating said ethanol feedstock to a temperature between 100 and 130° C. by heat exchange with the effluent from step e), b) a step of pretreating the ethanol feedstock on an acidic solid operating at a temperature between 100 and 130° C. so as to produce a pretreated ethanol feedstock, c) a step of vaporizing a vaporization feedstock comprising said pretreated ethanol feedstock and at least a portion of the flow of treated water recycled according to step h) in an exchanger by heat exchange with the effluent from the last reactor of step e), said vaporization feedstock being introduced into said vaporization step at a pressure between 0.1 and 1.4 MPa so as to produce a vaporized feedstock, d) a step of compressing said vaporized feedstock in a compressor so as to produce a compressed feedstock, e) a step of dehydrating said compressed feedstock in at least one adiabatic reactor containing at least one dehydration catalyst and in which the dehydration reaction takes place, operating at an inlet temperature between 350 and 550° C. and at an inlet pressure between 0.3 and 1.8 MPa, f) a step of separating the effluent from the last adiabatic reactor of step e) into an effluent comprising ethylene at a pressure below 1.6 MPa and an effluent comprising water, g) a step of purifying at least a portion of the effluent comprising water from step f) and separating at least one flow of treated water and at least one flow of unconverted ethanol, and h) a step of recycling at least a portion of the flow of treated water from step g) upstream of step c).