Patent ID: 7220349

Claim:
A process for producing middle distillates from a paraffin effluent produced by Fischer-Tropsch synthesis, comprising: a) optionally, fractionating the feed into at least one heavy fraction with an initial boiling point in the range 120-200° C., and at least one light fraction boiling below said heavy fraction; b) optionally, hydrotreating at least a portion of the effluent or the heavy fraction, optionally followed (step c) by eliminating at least a portion of any water present; d) passing at least a portion of the effluent or of the optionally hydrotreated fraction over a first hydroisomerisation/hydrocracking catalyst, which is an amorphous catalyst containing at least one noble group VIII metal and containing no added halogen; e) distilling the hydroisomerised/hydrocracked effluent to obtain middle distillates including kerosene, and/or gas oil and a residual fraction boiling above the middle distillates; f) passing at least a portion of said residual fraction and/or a portion of said middle distillates over a second hydroisomerisation/hydrocracking catalyst at different operating conditions than in (d), which catalyst is an amorphous catalyst containing at least one noble group VIII metal, and containing no added halogen, and distilling the resulting effluent to obtain middle distillates, in which a portion of at least one of the kerosine, gas oil cuts from step e) is recycled to step d) and the residual fraction undergoes step f), or in which at least one of the kerosine, gas oil cuts from step e) undergoes step f), and the residual fraction is recycled to step d).