METHOD FOR PRODUCING FEEDSTOCKS OF HIGH QUALITY LUBE BASE OIL FROM UNCONVERTED OIL OF FUELS HYDROCRACKER OPERATING IN RECYCLE MODE

摘要

A process method to produce the feedstocks for manufacturing high quality lube base oil of the present invention is utilizing theunconverted oil (UCO), which is produced from a fuels hydrocracker unit, to manufacture the feedstock oils of high quality lube baseoil with very high viscosity index and low volatility, in which a portion or all of the unconverted oil from the fuels hydrocracker unit iscontinuously fed to a second vacuum distillation process unit and the vacuum distillation unit will produce different grades of lube base oilfeedstocks with desired viscosity ranges, while this vacuum distillation unit can effectively remove the undesirable polynuclear aromaticsand heavy refractory hydrocarbons, which can accumulate in the recycle oil stream and can cause rapid decline in catalyst performance anddegradation in product selectivity to the hydrocracker unit in recycle mode.