| abstract |
The invention relates to a process for the production of middle distillates from a paraffinic feedstock produced by Fischer-Tropsch synthesis, using a hydrocracking / hydroisomerization catalyst which comprises at least one hydro-dehydrogenating element selected from the group formed by the elements. Group VIII noble substances of the Periodic Table, a non-zeolitic silica-alumina support containing an amount greater than 5% by weight and less than or equal to 95% by weight of silica (SiO2), a mean pore diameter, measured by mercury porosimetry , between 20 and 140 A, a total pore volume, measured by mercury porosimetry, of between 0.1 ml / g and 0.6 ml / g, a total pore volume, measured by nitrogen porosimetry, of between 0.1 ml and 0.6 ml / g, a BET specific surface area of between 100 and 550 m 2 / g, a pore volume, measured by mercury porosimetry, included in pores with a diameter greater than 140 A less than 0.1 ml / g , a vo porous lume, 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, included in pores with diameters greater than 200 A less than 0, 1 ml / g, a porous volume, measured by mercury porosimetry, included in pores with diameters greater than 500 A less than 0.01 ml / g and an X-ray diffraction diagram which contains at least the main lines characteristic of at least one of the transition aluminas included in the group consisting of alpha, rho, chi, eta, gamma, kappa, theta and delta alumina. |