Process for the dehydrogenation of ethanol in a multitubular reactor

A process for the dehydrogenation of ethanol to give acetaldehyde, comprising:

• a stage of dehydrogenation of a feedstock comprising ethanol, said dehydrogenation stage employing a reaction section comprising at least one reactor which comprises one or a plurality of tubes and a shell, said tube(s) each comprising at least one fixed bed of at least one dehydrogenation catalyst,
• said feedstock feeding said tube(s) in gaseous form, at an inlet temperature of said feedstock of greater than or equal to 240° C., at an inlet pressure of said feedstock of between 0.1 and 1.0 MPa, and at a weight hourly space velocity (WWH) of the feedstock at the inlet of between 2 and 15 h−1,
• a heat-transfer fluid circulating in said shell so that said heat-transfer fluid is introduced into said shell in gaseous form and is, at the shell outlet, at least partly in liquid form,
• said heat-transfer fluid being introduced into the shell at a flow rate such that the ratio of the flow rate by weight of said heat-transfer fluid at the shell inlet, with respect to the flow rate by weight of said feedstock at the inlet of the tube(s), is greater than or equal to 1.0,
• said heat-transfer fluid being introduced into the shell at an inlet temperature of the heat-transfer fluid of greater than or equal to 260° C. and less than or equal to 400° C., and at an inlet pressure of the heat-transfer fluid of greater than or equal to 0.10 MPa and less than or equal to 1.10 MPa, and
• said process producing a dehydrogenation effluent comprising at least acetaldehyde, hydrogen and unconverted ethanol.