Patent ID: 7326331

Claim:
A process for producing middle distillates from a paraffin feed produced by the Fischer-Tropsch process, comprising the following successive steps: a) separating a single fraction, termed the heavy fraction, with an initial boiling point in the range 120-200° C.; b) hydrotreating at least a portion of said heavy fraction; c) fractionating into at least three fractions: at least one intermediate fraction with an initial boiling point T 1 in the range 120° C. to 200° C., and an end point T 2 of more than 300° C. and less than 410° C.; at least one light fraction with a boiling point below that of the intermediate fraction; at least one heavy fraction with a boiling point above that of the intermediate fraction; d) passing at least a portion of said intermediate fraction over an amorphous hydroisomerisation/hydrocracking catalyst; e) passing at least a portion of said heavy fraction over an amorphous hydrocracking/hydroisomerisation catalyst; f) distilling the hydrocracked/hydroisomerised fractions to obtain middle distillates, and recycling the residual fraction with a boiling point above that of said middle distillates to step e) over the amorphous catalyst treating the heavy fraction, in which process reaction conditions in (d) favor hydroisomerization over hydrocracking, and reaction conditions in (e) favor hydrocracking over hydroisomerization, and wherein the catalysis in d) and e) are catalysts comprising at least one noble metal and a silica-alumina support.