Patent ID: 7156978

Claim:
A process for producing middle distillates from a paraffin feed produced by the Fischer-Tropsch process, comprising the following successive steps: 1) fractionating (step a) the feed 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; 2) hydrotreating (step b) at least a portion of said intermediate fraction then passing (step d) at least a portion of the hydrotreated fraction over an amorphous hydroisomerisation/hydrocracking catalyst under conditions favoring hydroisomerization over hydrocracking; 3) passing (step f) at least a portion of said heavy fraction over an amorphous hydrocracking/hydroisomerisation catalyst under conditions favoring hydrocracking over hydroisomerization with a conversion of 370° C.+ products into 370° C.− products of more than 80% by weight; 4) distilling (steps e and g) at least a portion of the hydrocracked/hydroisomerised fractions to obtain middle distillates.