TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The catalyst used in step (b) comprises at least one zeolite comprising ferrierite zeolites, NU-10, EU-1 and MBA-30, and/or MI-5.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The step (b) operates at a temperature of 250-600 degrees C, at a pressure of 0-5 MPa, and an hourly space velocity of 0.1-50 h-1. In the process, in which at least part of the gaseous effluent mainly having greater than or equal to 3C resulting from the separation step is recycled into upstream of step (b) for transforming purified charge into light olefin effluent. The gas effluent having a number of carbon atoms greater than or equal to 3 resulting from the separation step is fed into oligomerization reaction section comprising homogeneous metal catalyst or heterogeneous catalyst. In the process, in which the effluent obtained from the oligomerization reaction section is separated in a separation step mainly into a hydrocarbon compound effluent having at least 9 C and other hydrocarbon compound effluent having more than 9C. The effluent obtained from the reaction section of oligomerization is separated in a separation step into hydrocarbon compound effluent having less than 12C and other effluent mainly consisting of hydrocarbons having more than 12C. The hydrocarbon compound effluent having more than 9C or 12C is sent in step (e) of separating the effluent having less than 9C or 12C is sent in step (d) of oligomerization. The total olefin hydrocarbon liquid effluent mainly having more than 4C obtained from step (c) of separation is sent in step of oligomerization (d), by mixing with at least the portion of the hydrocarbon gas effluent mainly having greater than or equal to 3C obtained from step (c) and are not recycled from upstream of the step (b). The catalyst used in step (d) of oligomerization is an amorphous catalyst comprising silica-alumina. The catalyst used in step (d) of oligomerization comprises a zeolite comprising ZSM-5 zeolite, NU-10 and/or ZBM-30. In the process, in which at least a portion of the light effluent comprising 2-4C compounds and/or at least a portion of the gasoline fraction obtained from the fractionating step (e) is preferably recycled in step (d) of oligomerization of the process. In the process, in which at least a part of the middle distillate base obtained from the fractionating step (e) of the effluent obtained from the oligomerization reactor undergoes a hydrogenation step of olefins produced in the presence of a catalyst comprising at least one Group VIII metal comprising palladium and/or nickel, and a support comprising alumina, silica or silica-alumina. In the process, in which a separation step after the hydrogenation step is implemented to allow fractionating into a kerosene cut, gas oil cut and/or a cut having a boiling point greater than 360 degrees C. In the process, in which at least a part of the middle distillate base is recycled in step (c) of separation. EXAMPLE - Bioethanol charge composition comprising ethanol (99 wt.%), methanol (less than 0.05 wt.%), butanol (less than 0.1 wt.%), other alcohols (less than 0.05 wt.%), total content of alcohol other than ethanol (less than 0.2 wt.%), oxygenated compounds other than alcohols (less than 0.1 wt.%), water (less than 1 wt.%), total cationic impurities (less than 0.005 wt.%), and total anionic impurities (less than 0.005 wt.%) was purified. The purified charge was transformed into a light olefin effluent in the presence of zeolite catalyst (prepared by mixing the zeolite ferrierite obtained with SB3-type alumina, extruding the paste, drying at 120 degrees C for 5 hours and then calcining in dry air at 500 degrees C for 2 hours). Then, water was added to the mixture. The light olefin effluent was then subjected to a separation step to eliminate the least part of the formed water. The separated effluent was subjected to oligomerization in the presence of a zeolite catalyst (ZSM-5) at 250 degrees C at a pressure of 5 MPa and a weight hourly rate of 1 h-1. The effluent of oligomerization was then subjected to a fractionation step and then relaxed to 2.1 MPa and 150 degrees C to give a liquid phase and a gaseous phase. The latter obtained was then cooled to 40 degrees C. The condensed part was then mixed with the liquid phase obtained at 2.1 MPa and 150 degrees C. The separated effluent was worked up to give middle distillate hydrocarbon comprising diesel and kerosene.