Patent ID: 8734636

Claim:
A method for producing diesel fuel, comprising: fractionating a synthetic oil obtained by Fisher-Tropsch synthesis into a plurality of fractions including a middle fraction, and a wax fraction in a first fractionator, wherein the wax fraction contains a wax component heavier than the middle fraction; hydroisomerizing the middle fraction with a hydroisomerizing catalyst, thereby producing a hydroisomerized middle fraction; hydrocracking the wax fraction with a hydrocracking catalyst, thereby producing a hydrocracked wax decomposition compound; separating a mixture of the hydroisomerized middle fraction and the hydrocracked wax decomposition compound into a plurality of fractions including a kerosene fraction and a gas oil fraction by fractionation in a second fractionator; analyzing the composition of each of the plurality of fractions including the kerosene fraction and the gas oil fraction; predicting one or more properties of a diesel fuel formed from the fractions based on the composition of each of the fractions; determining a mixing ratio of the fractions so as to have the values of the properties within respective predetermined ranges; and mixing the fractions including the kerosene fraction and the gas oil fraction at the mixing ratio, thereby producing the diesel fuel.