Abstract:
Production of middle distillates from a feedstock produced by Fischer-Tropsch synthesis and containing oxygenated compounds:a) catalytic hydrotreating; b) hydroisomerization/hydrocracking at least a part of liquid and gaseous effluent originating from a); c) gas/liquid separation of the stream from b) into a gaseous fraction comprising predominantly hydrogen, a hydroisomerized/hydrocracked organic liquid fraction and an aqueous fraction; d) fractionation of the organic liquid fraction in c) to obtain at least one fraction of middle distillates; and e) catalytic methanation of CO and CO2 on at least a part of said gaseous fraction in c) before hydrotreating a), and/or on at least a part of the liquid and gaseous effluent originating from a) in which the hydrogen in a) is obtained at least partly from the gaseous fraction separated in c).