Fuels Hydrocracking With Dewaxing Of Fuel Products

CATEGORY: HYDROCRACKING
PATENT
Fuels Hydrocracking With Dewaxing Of Fuel Products
Pub. No.:    WO/2012/135403  
International Application No.:    PCT/US2012/031055
Publication Date:  04.10.2012
Applicants:  EXXONMOBIL RESEARCH AND ENGINEERING COMPANY [US/US]; 1545 Route 22 East P.O. Box 900 Annandale, NJ 08801-0900 (US) (For All Designated States Except US).
Inventors:
DOUGHERTY, Richard C.; (US).
NOVAK, William J.; (US).
SHIH, Stuart S.; (US).
McCARTHY, Stephen J.; (US).
DAAGE, Michel A.; (US)
Abstract: 
This invention relates to a process involving hydrocracking and dewaxing of a feedstream in which a converted fraction can correspond to a majority of the product from the reaction system, while an unconverted fraction can exhibit improved properties. In this hydrocracking process, it can be advantageous for the yield of unconverted fraction for gasoline fuel application to be controlled to maintain desirable cold flow properties for the unconverted fraction. Catalysts and conditions can be chosen to assist in attaining, or to optimize, desirable product yields and/or properties.
FIELD
(0001] The disclosures herein relate to hydrocarbon feedstocks and products, and hydrotreating processes thereof.
BACKGROUND
[0002] One method for increasing the feedstocks suitable for production of fuels can be to use cracking to convert higher boiling petroleum feeds to lower boiling products. For example, distillate boiling range feeds can be hydrocracked to generate additional naphtha boiling range products.
[0003] U.S. Patent 5,385,663 describes an integrated process for hydrocracking and catalytic dewaxing of middle distillates. An initial feed is hydrocracked to produce at least a middle distillate stream having a boiling range from 232°C - 450°C. This middle distillate stream is then de waxed. Some naphtha boiling range compounds are also produced, but an amount of conversion to lower boiling products is not specified.
[0004] U.S. Patent 5,603,824 describes a process for upgrading hydrocarbons to produce a distillate product and a high octane naphtha product. An initial feed suitable for distillate production is split into a lower boiling fraction and a higher boiling fraction at a cut point between about 500°C and 800°C. The higher boiling fraction is hydrocracked. The fractions are combined after hydrocracking for dewaxing. Because the lower boiling portion is not hydrocracked, the method has a substantial distillate yield.
[0005] U.S. Patent 5,730,858 describes a process for converting hydrocarbon feedstocks into middle distillate products. A feedstock is first treated with an aqueous acid solution. The feedstock is then subjected to hydrocracking and dewaxing. The target product appears to be a distillate product with a boiling range between 149°C and 300°C.
[0006] U.S. Patent Application Publication 2009/0159489 describes a process for making high energy distillate fuels. A highly aromatic feedstream is contacted with a hydrotreating catalyst, hydrocracking catalyst, and dewaxing catalyst in a single stage reactor. At least a portion of the highly aromatic stream is converted to a jet fuel or diesel product.
SUMMARY OF EMBODIMENTS OF THE INVENTION
[0007] In one embodiment of the invention herein is a method for producing a naphtha product and an unconverted product, comprising:
exposing a feedstock to a first hydrocracking catalyst under first effective hydroprocessing conditions to form a first hydrocracked effluent, the feedstock having a cetane number of about 35 or less, at least about 60 wt% of the feedstock boiling above about 400°F (about 204°C) and at least about 60 wt% of the feedstock boiling below about 650°F (about 343°C);
exposing the first hydrocracked effluent, without intermediate separation, to a first dewaxing catalyst under first effective dewaxing conditions to form a dewaxed effluent;
separating the dewaxed effluent to form a first gas phase portion and a first liquid phase portion;
fractionating the first liquid phase portion and a second liquid phase portion in a first fractionator to form at least one naphtha fraction and an unconverted fraction, the naphtha fraction corresponding to at least about 65 wt% of the feedstock and having a final boiling point of about 400°F (about 204°C) or less;
withdrawing at least a first portion of the uncoverted fraction as an unconverted product stream, the weight of the unconverted product stream corresponding to from about 5 wt% to about 35 wt% of the feedstock; wherein the unconverted product stream has an initial boiling point of at least about 400°F (about 204°C), a cetane number of at least about 45, and a cloud point at least about 10°F (about 6°C) less than the cloud point of the feedstock;
exposing at least a second portion of the unconverted fraction to a second hydrocracking catalyst under second effective hydroprocessing conditions to form a second hydrocracked effluent;
separating the second hydrocracked effluent to form a second gas phase portion and the second liquid phase portion; and
sending at least a portion of the second liquid phase portion to the first fractionator.
[0008] In another embodiment of the invention herein is a method for producing an improved octane naphtha product stream, comprising:
exposing a light cycle oil from a fluid catalytic cracking process to a first hydrocracking catalyst under first effective hydroprocessing conditions to form a first hydrocracked effluent, the Jight cycle oil having a cetane number of about 35 or less, at least about 60 wt% of the feedstock boiling above about 400°F (about 204°C) and at least about 60 wt% of the feedstock boiling below about 650°F (about 343°C);
exposing the first hydrocracked effluent, without intermediate separation, to a first dewaxing catalyst under first effective dewaxing conditions to form a dewaxed effluent;
separating the dewaxed effluent to form a first gas phase portion and a first liquid phase portion;
fractionating the first liquid phase portion and a second liquid phase portion in a first fractionator to form at least one naphtha fraction and an unconverted fraction, the naphtha fraction corresponding to at least about 65 wt% of the feedstock and having a final boiling point of about 400°F (about 204°C) or less;
withdrawing at least a portion of the unconverted fraction as an unconverted product stream, the weight of the unconverted product stream corresponding to from about 5 wt% to about 35 wt% of the light cycle oil; wherein the unconverted product stream has an initial boiling point of at least about 400°F (about 204°C), a cetane number of at least about 45, and a cloud point at least about 10°F (about 6°C) less than the cloud point of the light cycle oil;
exposing at least a second portion of the unconverted fraction to a second hydrocracking catalyst under second effective hydroprocessing conditions to form a second hydrocracked effluent;
separating the second hydrocracked effluent to form a second gas phase portion and the second liquid phase portion;
sending at least a portion of the second liquid phase portion to the first fractionator; and
sending the at least one naphtha fraction to a reformer unit and producing an improved naphtha product stream, wherein the improved naphtha product stream has a higher octane value (RON+MON) than the naphtha fraction.
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