FIELD: chemistry.
SUBSTANCE: invention relates to a method of obtaining middle distillates from paraffin raw material through Fischer-Tropsch synthesis using a hydrocracking/hydroisomerisation catalyst which contains at least one hydro-dehydrogenating element selected from a group comprising group VIB and VIII elements, 0.2-2.5 wt % oxide of a doping element selected from phosphorus, boron and silicon, and a non-zeolite carrier based on silicon dioxide-aluminium oxide, containing silicon dioxide (SiO2) in amount of more than 5 wt % and less than or equal to 95 wt %, whereby the said catalyst has the following characteristics: -average pore diametre measured through mercury porosimetry between 20 and 140 Å, -overall pore volume measured through mercury porosimetry between 0.1 ml/g and 0.5 ml/g, -overall pore volume measured through nitrogen porosimetry between 0.1 ml/g and 0.5 ml/g, -BET specific surface area between 100 and 500 m2/g, - pore volume measured through mercury porosimetry, included in pores with diametre greater than 140 Å, less than 0.1 ml/g, -pore volume measured through mercury porosimetry, included in pores with diametre greater than 160 Å, less than 0.1 ml/g, -pore volume measured through mercury porosimetry, included in pores with diametre greater than 200 Å, less than 0.1 ml/g, -pore volume measured through mercury porosimetry, included in pores with diametre greater than 500 Å, strictly greater than 0.01 and less than 0.1 ml/g, - X-ray diffractogram which contains at least main characteristic lines of at least one transition aluminium oxide included in a group comprising alpha-, rho-, chi-, eta-, gamma-, kappa-, theta- and delta-aluminium oxides, -catalyst packing density greater than 0.75 g/cm3, -phosphorus content in the catalyst is between 0.2 and 2.5% of the weight of oxide.
EFFECT: high output of middle distillates.
21 cl, 9 ex, 4 tbl, 4 dwg
