NOVELTY - Dehydrating an ethanol filler to ethylene comprises: (a) vaporizing the ethanol filler mixed with at least part of the flow of recycled purified water; (b) compressing the vaporized mixture in a compressor; (c) introducing the vaporized and compressed mixture into at least one adiabatic reactor; (d) separating an effluent from the last adiabatic reactor into an effluent comprising ethylene and water; (e) purifying at least a portion of the effluent and separating at least a flow of purified water and a stream of non-converted ethanol; and (f) recycling the flow of purified water.    USE - The method is useful for dehydrating the ethanol filler to ethylene (claimed), where the dehydrated ethylene filler is useful for synthesizing alcohol from fossil fuels including coal, natural gas and carbon-containing wastes.    ADVANTAGE - The method dehydrates the ethanol filler to ethylene with high purity and less energy consumption.    DETAILED DESCRIPTION - Dehydrating an ethanol filler to ethylene comprises: (a) vaporizing the ethanol filler mixed with at least part of the flow of recycled purified water in a heat exchanger by heat exchange with the effluent from the last reactor, where the mixture is introduced into the vaporizing step at a pressure of 0.1-0.4 MPa; (b) compressing the vaporized mixture in a compressor; (c) introducing the vaporized and compressed mixture at an input temperature of 350-500 degrees C and at an inlet pressure of 0.2-1.3 MPa, into at least one adiabatic reactor containing at least one dehydration catalyst, where dehydration reaction takes place in the presence of the dehydration catalyst; (d) separating the effluent from the last adiabatic reactor into the effluent comprising ethylene at a pressure less than 1 MPa and the effluent comprising water; (e) purifying at least a portion of the effluent comprising water and separating at least a flow of purified water and of at least a stream of non-converted ethanol; and (f) recycling at least part of the flow of purified water from step (e) to step (a).