PURPOSE: To produce gasoline having a high octane value and low in sulfur content and diesel fuel of improved quality at the same time by hydrogenating cycle oil separated after catalytic cracking and subjecting the hydrogenated oil to hydrocracking before the fractionating the same.
CONSTITUTION: A hydrocarbon raw material is introduced into a fluidized bed catalytic cracking apparatus (FCC) from a line 11 to be dealkylated and the cracked product is introduced into a distillation tower 12 through a line 13 and light cut cycle oil (325°C or lower) is taken out to be guided to a hydrogenation apparatus 20 through a line 14 along with hydrogen introduced from a line 15 to remove a compd. of sulfur or nitrogen and the hydrogenated cycle oil is sent to a hydrocracking apparatus 21. Herein, the cycle oil is hydrocracked so that hydrogen partial pressure is 8275 kPa or less and a gasoline conversion ratio becomes 75 wt.% or less. This effluence (containing a first distilled oil fraction and a paraffinic second distilled oil fraction) is sent to a separator 22 and a distillation tower 23 and the first distilled oil fraction is recycled to the FCC apparatus and gasoline and diesel oil are respectively taken out of a tower top and a tower bottom.
MAIKERU SEBASUCHIYAN SAARI
PIITAA JIYOZEFU OOUENZU
