Patent ID: 11859142
Assignee: UOP LLC
Field: Basic materials chemistry (Chemistry)
Classification: CPC C | IPC C

Claim 13:
14. A hydrocracking process for maximization of naphtha while producing base oil, comprising:
hydrocracking a hydrocarbon feed stream in a first stage hydrocracking reactor to produce a first hydrocracked effluent stream;
passing the first hydrocracked effluent stream to a first stage hot separator to provide a first hot separated vapor hydrocracked stream and a first hot separated liquid hydrocracked stream;
passing the first hot separated liquid hydrocracked stream to a first stage hot flash drum to provide a first hot vapor hydrocracked stream and a first hot liquid hydrocracked stream;
passing the first hot vapor hydrocracked stream, a second hot vapor hydrocracked stream and a cold separated liquid hydrocracked stream to a cold flash drum to provide a cold liquid stream;
fractionating the cold liquid stream and the first hot liquid hydrocracked stream in a first stage fractionation column to provide a naphtha stream, a kerosene stream, a diesel stream and a first unconverted oil stream;
hydrocracking a second unconverted oil stream and a recycle stream comprising a portion of the kerosene stream, a portion of the diesel stream, and a portion of the first unconverted oil stream in a second stage hydrocracking reactor to produce a second hydrocracked effluent stream;
passing the second hydrocracked effluent stream to a second stage hot separator to provide the second hot separated vapor hydrocracked stream and a second hot separated liquid hydrocracked stream;
passing the second hot separated liquid hydrocracked stream to a second stage hot flash drum to provide the second hot vapor hydrocracked stream and a second hot liquid hydrocracked stream;
fractionating the second hot liquid hydrocracked stream in a second stage fractionation column to provide the second unconverted oil stream;
withdrawing a remaining portion of the first unconverted oil stream for base oil production; and
withdrawing a UCO drag stream comprising about 0.1 wt % to about 5 wt % of said hydrocarbon feed stream from said second unconverted oil stream,
wherein catalyst in the second stage hydrocracking reactor has higher zeolite content and/or higher metals content as compared to the catalyst in the first stage hydrocracking reactor.