| abstract |
The invention relates to a method for producing middle distillates from of a paraffinic feedstock produced by Fischer-Tropsch synthesis, using a hydrocracking / hydroisomerization catalyst which comprises 0.2 to 2.5% oxide weight of a doping element selected from boron, phosphorus, silicon, least one hydro-dehydrogenating element selected from the group consisting of noble elements of group VIII of the Periodic Table, a non-silica-alumina zeolite containing more than 5% weight and less than or equal to 95% by weight of silica (SiO2), an average diameter porous, measured by mercury porosimetry, between 20 and 140 A, a volume total porosity, measured by mercury porosimetry, between 0.1 ml / g and 0.6 ml / g, a total pore volume, measured by nitrogen porosimetry, between 0.1 ml / g and 0.6 ml / g, a BET specific surface area of between 100 and 550 m 2 / g, a porous volume, measured by mercury porosimetry, included in the pores of diameter greater than 140 A less than 0.1 ml / g, a pore volume, measured by mercury porosimetry, included in pores with diameters greater than 160 A less than 0.1 ml / g, a pore volume, measured by mercury porosimetry, in pores greater than 200 A in diameter less than 0.1 ml / g; porous volume, measured by mercury porosimetry, included in the pores of diameter greater than 500 A less than 0.1 ml / g and a X-ray diffraction which contains at least the main characteristic lines at least one of the transition aluminas included in the group consisting of alpha, rho, chi, eta, gamma, kappa, theta and delta alumina. |