METHOD OF PROCESSING FISCHER-TROPSCH SYNTHETIC OIL TO MANUFACTURE DIESEL FUEL BASE STOCK AND METHOD OF CALCULATING CRACKING RATE UPON HYDROCRACKING WAX FRACTION

摘要

An object of the present invention is to provide a method of processingFischer-Tropsch synthetic oil to manufacture a diesel fuel base stock, themethodincluding: (a) fractionating, in a fractionator, Fischer-Tropsch synthetic oilobtained by aFischer-Tropsch synthesis method into at least two fractions of a middlefractioncontaining a component having a boiling point range corresponding to dieselfuel oil anda wax fraction containing a wax component heavier than the middle fraction;(b) bringingthe wax fraction into contact with a hydrocracking catalyst in a hydrocrackingreactor toobtain a hydrocracked product; (c) separating a gas component from thehydrocrackedproduct to produce hydrocracked oil in a gas-liquid separator disposed in therear of thehydrocracking reactor used in the step (b); (d) measuring the composition ofthe gascomponent seperated in the step (c); (e) calculating a cracking rate in thehydrocrackingreaction based on the composition of the gas component measured in the step(d); and (f)controlling an operation condition of the hydrocracking reactor so that thecracking ratecalculated in the step (e) agrees with an objective cracking rate.Furthermore, anotherobject of the present invention is to provide a method of calcurating thecracking rate inhydrocracking the wax fraction obtained by fractionating the Fischer-Tropschsyntheticoil in the fractionator.