The M.w. Kellogg Company

Mobil Oil Corporation

Michael G Hunter

Kenneth W Goebel

Randall D Partridge

David A Pappal

Timothy L Hilbert

Arthur R Gentry

This invention relates to the refining of petroleum products, and more particularly to an integrated hydroprocessing scheme involving a hydrocracking stage and subsequent dewaxing stage. Materials boiling in the middle distillate or lube oil range may be dewaxed. The bottoms streams (and optionally, other streams) of each stage are maintained separately from one another, during processing. Dewaxing may occur using either hydroisomerization catalysts or shape-selective catalysts or both in series. One embodiment employs a baffle in the flash zone of a fractionator to separate bottoms streams from each other. Alternatively, the effluent from the hydrocracking stage may be processed separately from the effluent from the dewaxing stage. The bottoms fraction from the dewaxing stage may be recycled back to the hydrocracking stage for further processing or used as lube base stock.

Integrated hydroprocessing scheme with segregated recycle

Hydrocarbon feedstocks are hydroprocessed in parallel reactors, while hydrogen flows in series between the reactors. A first hydrocarbon feedstock and a hydrogen-rich recycle gas stream are introduced to a first reactor, where a first reactor effluent stream is produced and fed to a first separator, which separates the first reactor effluent stream into a first hydrogen-rich gas stream and a first hydroprocessed product stream. The first hydrogen-rich gas stream and a second hydrocarbon feedstock are fed to a second reactor, where a second reactor effluent stream is produced and fed to a second separator, which separates the second reactor effluent stream into a second hydrogen-rich gas stream and a second hydroprocessed product stream. A make-up hydrogen stream is added to the second hydrogen-rich gas to form the hydrogen-rich recycle gas stream that is compressed and fed to the first reactor.

Two-stage hydroprocessing reaction scheme with series recycle gas flow

An integrated three-column process for recovering hydrocarbon distillate products from a hydroprocessing or hydrocracking reactor effluent stream and a hydrocarbon distillate product recovery train are disclosed. According to the present recovery process, an effluent stream from the cracking reactor is cooled and separated into light and heavy phase streams. The heavy phase stream is depressurized and stripped of light end components in a steam stripping column. The light phase stream is further cooled to separate a liquid stream which is combined with the light ends from the stripper and fed to a debutanizer. A C.sub.4 -rich light end stream taken overhead from the debutanizer is condensed to produce LPG product stream(s). A C.sub.4 -lean heavy end stream removed from the bottoms of the debutanizer is combined with a heavy end bottoms stream from the stripper and fed to a fractionator for fractionation into product distillate streams such as light and heavy naphtha, jet fuel, diesel oil, and the like. A heavy oil bottoms stream recovered from the fractionator is recycled back to the cracking reactor.

Integrated distillate recovery process

An integrated middle distillate upgrading process and unit are disclosed. A middle distillate side-stream of a conventional single stage hydrocracking process is circulated to a hydrotreating stage such as an aromatics saturation reactor and/or a catalytic dewaxing reactor to effect middle distillate upgrade. The upgraded product is then finished in a fractionation stage side-stripper column. The integrated hydrotreating reactor can share the duty of existing hydrocracker stage equipment and take advantage of existing process heat to eliminate the need for much of the equipment generally required by a stand-alone hydrotreating reactor of the prior art.

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Katy, TX, United States of America

Michael G Hunter