U.S. patent application number 14/980432 was filed with the patent office on 2016-07-07 for catalytic and solvent processing for base oil production.
The applicant listed for this patent is Jean P. Andre, James W. Gleeson, Teck-Mui Hoo, Bal K. Kaul, Jeenok T. Kim, Carlos N. Lopez, Benjamin S. Umansky, Nicole D. Vaughn, Lei Zhang. Invention is credited to Jean P. Andre, James W. Gleeson, Teck-Mui Hoo, Bal K. Kaul, Jeenok T. Kim, Carlos N. Lopez, Benjamin S. Umansky, Nicole D. Vaughn, Lei Zhang.
Application Number | 20160194566 14/980432 |
Document ID | / |
Family ID | 55135548 |
Filed Date | 2016-07-07 |
United States Patent
Application |
20160194566 |
Kind Code |
A1 |
Hoo; Teck-Mui ; et
al. |
July 7, 2016 |
CATALYTIC AND SOLVENT PROCESSING FOR BASE OIL PRODUCTION
Abstract
Methods are provided for producing lubricant base oils using a
combination of catalytic and solvent processing. By using a
combination of catalytic processing for feed conversion and
dewaxing while using solvent processing for removal of aromatics,
Group II and Group III lubricant base oils can be produced using
low pressure catalytic processes.
Inventors: |
Hoo; Teck-Mui; (Conroe,
TX) ; Vaughn; Nicole D.; (Spring, TX) ;
Umansky; Benjamin S.; (Fairfax, VA) ; Gleeson; James
W.; (Magnolia, TX) ; Kim; Jeenok T.;
(Shenandoah, TX) ; Lopez; Carlos N.; (Amissville,
VA) ; Andre; Jean P.; (Oakton, VA) ; Zhang;
Lei; (Basking Ridge, NJ) ; Kaul; Bal K.;
(Fairfax, VA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hoo; Teck-Mui
Vaughn; Nicole D.
Umansky; Benjamin S.
Gleeson; James W.
Kim; Jeenok T.
Lopez; Carlos N.
Andre; Jean P.
Zhang; Lei
Kaul; Bal K. |
Conroe
Spring
Fairfax
Magnolia
Shenandoah
Amissville
Oakton
Basking Ridge
Fairfax |
TX
TX
VA
TX
TX
VA
VA
NJ
VA |
US
US
US
US
US
US
US
US
US |
|
|
Family ID: |
55135548 |
Appl. No.: |
14/980432 |
Filed: |
December 28, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62097649 |
Dec 30, 2014 |
|
|
|
Current U.S.
Class: |
208/60 ; 208/64;
208/89 |
Current CPC
Class: |
C10G 65/043 20130101;
C10G 67/16 20130101; C10G 21/16 20130101; C10G 25/003 20130101;
C10G 45/58 20130101; C10G 21/27 20130101; C10G 67/0409 20130101;
C10G 2300/301 20130101; C10G 25/03 20130101; C10G 2400/10 20130101;
C10G 67/04 20130101; C10G 69/02 20130101; C10G 2300/302 20130101;
C10G 67/00 20130101; C10G 67/0418 20130101; C10G 2300/202 20130101;
C10M 101/02 20130101; C10G 67/06 20130101 |
International
Class: |
C10G 69/02 20060101
C10G069/02; C10M 101/02 20060101 C10M101/02 |
Claims
1. A method for forming a lubricant base stock, comprising:
hydroprocessing a feedstock having a T5 boiling point greater than
600.degree. F. (316.degree. C.) and a sulfur content of at least
500 wppm under effective hydroprocessing conditions to form a
hydroprocessed effluent, the effective hydroprocessing conditions
including a total pressure of less than 1500 psig (10.3 MPag);
separating the hydroprocessed effluent to form at least a gas phase
effluent and a hydroprocessed liquid product effluent having a
sulfur content of less than 500 wppm; dewaxing at least a first
portion of the hydroprocessed liquid product effluent to form a
dewaxed effluent; extracting at least a second portion of the
hydroprocessed liquid product effluent in the presence of an
extraction solvent to form a raffinate product and an extract
product, the raffinate product having a sulfur content of 300 wppm
or less; and fractionating at least a portion of the raffinate
product to form at least a lubricant base stock product having a
viscosity index of at least 80, and an aromatics content of 2.5 wt
% or less.
2. The method of claim 1, wherein dewaxing at least a first portion
of the hydroprocessed liquid product effluent comprises exposing
the at least a first portion of the hydroprocessed liquid product
effluent to a dewaxing catalyst under effective catalytic dewaxing
conditions to form the dewaxed effluent, the effective catalytic
dewaxing conditions including a total pressure of 300 psig (2.1
MPag) to 700 psig (4.8 MPag), wherein extracting at least a second
portion of the hydroprocessed liquid product effluent comprises
extracting at least a portion of the dewaxed effluent.
3. The method of claim 2, wherein the effective dewaxing conditions
comprise a total pressure of 400 psig (2.8 MPag) to 600 psig (4.2
MPag), the effective dewaxing conditions are effective for
conversion of 1 wt % to 10 wt % of the at least a portion of the
hydroprocessed liquid product effluent, or a combination
thereof
4. The method of claim 2, wherein the dewaxed effluent has an
aromatics content of 5 wt % to 30 wt %.
5. The method of claim 1, further comprising hydrofining at least a
portion of the raffinate product under effective hydrofining
conditions to form a hydrofined raffinate, wherein dewaxing at
least a first portion of the hydroprocessed liquid product effluent
comprises solvent dewaxing at least a portion of the hydrofined
raffinate.
6. The method of claim 1, further comprising hydrofinishing at
least a portion of the dewaxed effluent under effective
hydrofinishing conditions.
7. The method of claim 1, wherein fractionating the at least a
portion of the raffinate product further comprises forming a
distillate boiling range product.
8. The method of claim 1, further comprising separating the dewaxed
effluent to form a fraction having a T5 boiling point of at least
500.degree. F. (260.degree. C.) and at least one fuel product, the
at least one fuel product being a naphtha boiling range product or
a distillate fuel boiling range product, wherein extracting at
least a portion of the dewaxed effluent comprises extracting at
least a portion of the fraction having a T5 boiling point of at
least 500.degree. F. (260.degree. C.).
9. The method of claim 1, wherein separating the hydroprocessed
effluent further comprises forming at least one fuel product, the
at least one fuel product being a naphtha boiling range product or
a distillate fuel boiling range product.
10. The method of claim 1, wherein the effective hydroprocessing
conditions comprise a total pressure of 750 psig (5.2 MPag) to 1500
psig (10.4 MPag), the effective hydroprocessing conditions comprise
effective hydrotreating conditions or effective hydrocracking
conditions, or a combination thereof.
11. The method of claim 1, wherein the effective hydroprocessing
conditions are effective for conversion of 5 wt % to 30 wt % of the
feedstock having a T5 boiling point greater than 600.degree. F.
(316.degree. C.) relative to a conversion temperature of
700.degree. F. (371.degree. C.).
12. The method of claim 1, wherein the hydroprocessed liquid
product effluent has a sulfur content of 100 wppm or less.
13. The method of claim 1, wherein the extraction solvent is methyl
pyrollidone (NMP), furfural, phenol, SO.sub.2, sulfolane,
dimethylsulfoxide, or combination thereof.
14. A method for forming a lubricant base stock, comprising:
hydroprocessing a feedstock having a T5 boiling point greater than
600.degree. F. (316.degree. C.) and a sulfur content of at least
500 wppm under effective hydroprocessing conditions to form a
hydroprocessed effluent, the effective hydroprocessing conditions
including a total pressure of less than 1500 psig; separating the
hydroprocessed effluent to form at least a gas phase effluent and a
hydroprocessed liquid product effluent having a sulfur content of
less than 500 wppm; exposing at least a portion of the
hydroprocessed liquid product effluent to a dewaxing catalyst under
effective catalytic dewaxing conditions to form a dewaxed effluent,
the effective catalytic dewaxing conditions including a total
pressure of 300 psig to 700 psig; extracting at least a portion of
the dewaxed effluent in the presence of an extraction solvent to
form a raffinate product and an extract product, the raffinate
product having a sulfur content of 300 wppm or less; and
fractionating at least a portion of the raffinate product to form
at least a lubricant base stock product having a viscosity index of
at least 80, and an aromatics content of 2.5 wt % or less.
15. A method for forming a lubricant base stock, comprising:
hydroprocessing a feedstock having a T5 boiling point greater than
600.degree. F. (316.degree. C.) and a sulfur content of at least
500 wppm under effective hydroprocessing conditions to form a
hydroprocessed effluent; exposing at least a portion of the
hydroprocessing effluent to a dewaxing catalyst under effective
catalytic dewaxing conditions to form a hydroprocessed, dewaxed
effluent, the hydroprocessed, dewaxed effluent comprising a
lubricant base oil fraction having an aromatics content of at least
3 wt %, the lubricant base oil fraction including a first lubricant
base oil portion and a second lubricant base oil portion; exposing
the first lubricant base oil portion to an adsorbent to form an
aromatics-depleted first lubricant base oil portion, the first
lubricant base oil portion comprising 20 wt % to 70 wt % of the
lubricant base oil fraction, an aromatics content of the
aromatics-depleted first lubricant base oil portion being 500 wppm
or less; and combining the aromatics-depleted first lubricant base
oil portion with the second lubricant base oil portion.
16. The method of claim 15, wherein the adsorbent comprises one or
more of zeolites, active carbon, mesoporous silica, materials
corresponding to the M41S family of materials, and sulfonated
polymers.
17. The method of claim 15, wherein the adsorbent comprises one or
more of zeolite Beta, USY, zeolite 5A, zeolite 13X, MCM-22, MCM-68,
ZSM-5, MCM-41, Amberlyst acid ion exchanged resin and Nafion.
18. The method of claim 15, wherein the adsorbent comprises metal
cations, the metal cations comprising cations of Ag, Na, Ca, Cu, or
a combination thereof.
19. The method of claim 15, further comprising exposing the
adsorbent to a desorption solvent to form an aromatics extract
fraction.
20. The method of claim 15, further comprising hydrofinishing at
least a portion of the hydroprocessed, dewaxed effluent to form a
hydrofinished effluent, the hydrofinished effluent comprising the
lubricant base oil fraction.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application Ser. No. 62/097,649 filed Dec. 30, 2014, which is
herein incorporated by reference in its entirety.
FIELD
[0002] Systems and methods are provided for production of lubricant
oil basestocks by a combination of catalytic and solvent
processing.
BACKGROUND
[0003] Dewaxing is a commonly used technique for improving the
properties of a petroleum fraction for use in various products,
such as fuels or lubricant base stocks. Historically, solvent
dewaxing was the first type of dewaxing used for modifying the
properties of a feedstock. Solvent extraction and dewaxing allowed
for separation of a feedstock into a raffinate fraction for use as
a distillate fuel or lubricant, an aromatics fraction, and a waxy
fraction. More recently, catalytic dewaxing has been commonly used
for improving the properties of feeds for use in fuels or lubricant
base stocks.
[0004] U.S. Pat. No. 4,259,170 describes a process for
manufacturing lube basestocks. In the process, one or more lower
boiling fractions from a vacuum distillation tower are solvent
dewaxed to form lubricant base stocks. One or more higher boiling
fractions are catalytically dewaxed in order to provide a pour
point improvement for the higher boiling fractions that is greater
than the amount that can be achieved by solvent dewaxing.
[0005] U.S. Pat. No. 6,773,578 describes a process for preparing
lubes with high viscosity index values. The process includes
obtaining a first feedstock that includes at least 95% of material
that boils below 1150.degree. F. (621.degree. C.), and a second
feedstock that includes at least 95% of material that boils above
1150.degree. F. (621.degree. C.). The feedstock containing the
portion that boils below 1150.degree. F. is catalytically dewaxed.
The feedstock containing the portion that boils above 1150.degree.
F. is solvent dewaxed and optionally also catalytically dewaxed.
Performing solvent dewaxing on the above 1150.degree. F. portion is
described as reducing the difference between the cloud point and
the pour point for the resulting products.
[0006] U.S. Patent Application Publication 2014/0042056 describes a
process for preparing multiple base oils from a feedstock. A lower
boiling portion of a feedstock is catalytically dewaxed to form
light neutral base oil(s) while a higher boiling portion of a
feedstock is solvent processed to form heavy neutral or brightstock
base oil(s).
[0007] U.S. Pat. No. 6,592,748 describes a raffinate
hydroconversion process. After solvent extraction, the raffinate is
exposed to a severe hydroconversion process followed by a cold
hydrofinishing process to form a lubricating oil basestock.
SUMMARY
[0008] In an aspect, a method for forming a lubricant base stock is
provided, the method including hydroprocessing a feedstock having a
T5 boiling point greater than about 600.degree. F. (316.degree. C.)
and a sulfur content of at least about 500 wppm under effective
hydroprocessing conditions to form a hydroprocessed effluent, the
effective hydroprocessing conditions including a total pressure of
less than about 1500 psig (10.3 MPag); separating the
hydroprocessed effluent to form at least a gas phase effluent and a
hydroprocessed liquid product effluent having a sulfur content of
less than 500 wppm; dewaxing at least a first portion of the
hydroprocessed liquid product effluent to form a dewaxed effluent;
extracting at least a second portion of the hydroprocessed liquid
product effluent in the presence of an extraction solvent to form a
raffinate product and an extract product, the raffinate product
having a sulfur content of about 300 wppm or less; and
fractionating at least a portion of the raffinate product to form
at least a lubricant base stock product having a viscosity index of
at least about 80, and an aromatics content of about 3.0 wt % or
less, or about 2.5 wt % or less, or about 2.0 wt % or less, or
about 1.5 wt % or less, or about 1.0 wt % or less.
[0009] In another aspect, a method for forming a lubricant base
stock is provided, the method including hydroprocessing a feedstock
having a T5 boiling point greater than about 600.degree. F.
(316.degree. C.) and a sulfur content of at least about 500 wppm
under effective hydroprocessing conditions to form a hydroprocessed
effluent, the effective hydroprocessing conditions including a
total pressure of less than about 1500 psig (10.3 MPag); separating
the hydroprocessed effluent to form at least a gas phase effluent
and a hydroprocessed liquid product effluent having a sulfur
content of less than 500 wppm; exposing at least a portion of the
hydroprocessed liquid product effluent to a dewaxing catalyst under
effective catalytic dewaxing conditions to form a dewaxed effluent,
the effective catalytic dewaxing conditions including a total
pressure of about 300 psig (2.1 MPag) to about 700 psig (4.8 MPag);
extracting at least a portion of the dewaxed effluent in the
presence of an extraction solvent to form a raffinate product and
an extract product, the raffinate product having a sulfur content
of about 300 wppm or less; and fractionating at least a portion of
the raffinate product to form at least a lubricant base stock
product having a viscosity index of at least about 80, and an
aromatics content of about 3.0 wt % or less, or about 2.5 wt % or
less, or about 2.0 wt % or less, or about 1.5 wt % or less, or
about 1.0 wt % or less.
[0010] In still another aspect, a method for forming a lubricant
base stock is provided, the method including hydroprocessing a
feedstock having a T5 boiling point greater than about 600.degree.
F. (316.degree. C.) and a sulfur content of at least about 500 wppm
under effective hydroprocessing conditions to form a hydroprocessed
effluent; exposing at least a portion of the hydroprocessing
effluent to a dewaxing catalyst under effective catalytic dewaxing
conditions to form a hydroprocessed, dewaxed effluent, the
hydroprocessed, dewaxed effluent comprising a lubricant base oil
fraction having an aromatics content of at least about 3 wt %, the
lubricant base oil fraction including a first lubricant base oil
portion and a second lubricant base oil portion; exposing the first
lubricant base oil portion to an adsorbent to form an
aromatics-depleted first lubricant base oil portion, the first
lubricant base oil portion comprising about 20 wt % to about 70 wt
% of the lubricant base oil fraction, an aromatics content of the
aromatics-depleted first lubricant base oil portion being about 500
wppm or less; and combining the aromatics-depleted first lubricant
base oil portion with the second lubricant base oil portion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 schematically shows an example of a configuration
suitable for processing a feedstock using both catalytic and
solvent processing to form base oil products.
[0012] FIG. 2 schematically shows an example of a configuration for
removing aromatics from a catalytically processed feed.
[0013] FIG. 3 shows a comparison of adsorbent selectivity for
adsorption of aromatics.
[0014] FIG. 4 shows a comparison of adsorbent capacity for
adsorption of aromatics.
DETAILED DESCRIPTION
[0015] All numerical values within the detailed description and the
claims herein are modified by "about" or "approximately" the
indicated value, and take into account experimental error and
variations that would be expected by a person having ordinary skill
in the art.
Overview
[0016] In various aspects, methods are provided for producing
lubricant base oils using a combination of catalytic and solvent
processing. By using a combination of catalytic processing for feed
conversion and dewaxing while using solvent processing for removal
of aromatics, Group II and Group III lubricant base oils can be
produced using low pressure catalytic processes. This can provide a
variety of advantages. One advantage of low pressure catalytic
processing is that the amount of hydrogen required for forming a
lubricant base oil can be substantially reduced. In a conventional
process, large hydrogen consumption and/or large
hydrogen-containing treat gas rates are required in order to
provide sufficient aromatic saturation. By contrast, in various
aspects, after catalytic processing at low pressure of a suitable
feedstock for formation of lubricant base oil(s), a solvent
extraction process can be used to reduce the aromatics content to a
desired level, such as less than about 3.0 wt %, or less than about
2.5 wt %, or less than about 2.0 wt %, or less than about 1.5 wt %,
or less than about 1.0 wt %.
[0017] Conventionally, a feedstock for lubricant base oil
production is processed either using solvent dewaxing or using
catalytic dewaxing. For example, in a lube solvent plant, a vacuum
gas oil (VGO) or another suitable feed is fractionated into light
neutral (LN) and heavy neutral (HN) distillates and a bottom
fraction by some type of vacuum distillation. The bottoms fraction
is subsequently deasphalted to recover an asphalt fraction and a
deasphalted oil. The LN distillate, HN distillate, and deasphalted
oil are then solvent extracted to remove the most polar molecules
as an extract and corresponding raffinates of LN distillate, HN
distillate, and deasphalted oil. The raffinates are then solvent
dewaxed to obtain dewaxed base oils of LN distillate, HN
distillate, and deasphalted oil with acceptable low temperature
properties. It is beneficial to hydrofinish the lubricant
basestocks either before or after the solvent dewaxing step. The
resulting lubricant basestocks may contain a significant amount of
aromatics (up to 50%) and high sulfur (>300 ppm). Thus, the
typical base oils formed from solvent processing alone are Group I
base stocks. As an alternative, a raffinate hydroconversion step
can be performed prior to the solvent dewaxing. The hydroconversion
is essentially a treatment under high H.sub.2 pressure in presence
of a metal sulfide based hydroprocessing catalyst which removes
most of the sulfur and nitrogen. The amount of conversion in the
hydroconversion reaction is typically tuned to obtain a
predetermined increase in viscosity index and saturates. This
allows the solvent dewaxed lubricant base stock products to be used
as Group II or Group II+ base stocks. Optionally, the wax recovered
from a solvent dewaxing unit may also be processed by catalytic
dewaxing to produce Group III or Group III+ lubricant base
stocks.
[0018] Current commercial methods for production of Group II and
Group III base oils typically use solvent processing in only a
limited manner. With the exception of solvent deasphalting at early
stages of handling a crude oil fraction, processes for formation of
Group II and Group III base oils typically correspond to catalytic
processes, such as hydrotreating, hydrocracking, catalytic
dewaxing, and/or aromatic saturation (sometimes referred to as
hydrofinishing). Catalytic processing can be effective for
producing Group II and Group III base oils having various viscosity
index, viscosity, and/or pour point values. However, in order to
reduce the aromatics content of the lubricant base oils to a
desired level, high pressure hydroprocessing is typically required.
Hydrogen is typically a limited resource in a refinery setting, so
processing improvements that can allow for production of a high
value product, such as a lubricant base oil, while reducing or
minimizing the hydrogen consumption are highly desirable.
Additionally, performing a sufficient amount of hydrocracking to
reduce the aromatics content of a heavy oil fraction, such as a
feed having at least 50 wt % of compounds with a boiling point of
about 900.degree. F. (482.degree. C.) or more, can lead to
overcracking of the heavy oil fraction.
[0019] In contrast to conventional methods, in various aspects a
feedstock suitable for forming lubricant base oil products can be
processed in a reaction system using catalytic processing to
achieve desired levels of heteroatom removal, viscosity index
improvement, and pour point reduction. A solvent extraction process
can then be used to reduce the aromatics content to a desired
level. For example, a vacuum gas oil or other suitable feedstock
can be hydroprocessed (hydrotreated and/or hydrocracked) under sour
conditions for heteroatom removal and optionally for improvement of
viscosity index and then catalytically dewaxed (sweet or sour
conditions) to improve cold flow properties. The hydroprocessing
can be performed at a pressure of 1500 psig (10.3 MPag), while the
catalytic dewaxing can be performed at a pressure of about 700 psig
(4.8 MPag) or less. These pressures are substantially lower than
conventional conditions for catalytic processing of a lubricant
base oil. As a result, the effluent generated from the catalytic
dewaxing has a higher than expected aromatics content, such as an
aromatics content of about 5 wt % to about 30 wt %. The aromatics
content is then reduced to less than about 3.0 wt %, or less than
about 2.5 wt %, or less than about 2.0 wt %, or less than about 1.5
wt %, or less than about 1.0 wt %, using a solvent extraction
process. Optionally, the dewaxed effluent and extracted effluent
can be hydrofinished in suitable manner for production of a
lubricant base oil. The extract from the solvent extraction can
also correspond to an upgraded product due to the hydroprocessing
that occurs prior to the solvent extraction.
[0020] In some alternative aspects, instead of performing catalytic
dewaxing, solvent dewaxing can be used. In such aspects, after the
initial hydroprocessing, at least a portion of the hydroprocessed
effluent can be solvent extracted. The raffinate from extraction
can then be hydrofined followed by solvent dewaxing. Hydrofining
conditions can correspond to hydrotreating conditions,
hydrofinishing conditions, or a combination thereof.
[0021] In various additional or alternative aspects, methods are
provided for using an adsorbent to reduce the aromatics content of
a potential lubricant base oil. A feed being processed for
lubricant base oil formation can end up with an excess amount of
aromatics for a variety of reasons. For example, during production
of a Group II base oil, a hydrotreating process may be less
effective than desired, resulting in a potential base oil after
hydrotreating with an aromatics content of at least about 3 wt %,
or at least about 5 wt %. As another example, during catalytic
processing to form a Group II base oil, the final hydrofinishing
catalyst for controlling aromatics content can deactivate over
time. However, it may not be desirable to stop base oil production
to change out all or a portion of the catalyst. As a result, near
the end of the useful processing lifetime for a hydrofinishing
catalyst, the aromatics content of a resulting Group II or Group
III base oil may increase.
[0022] In order to reduce the aromatics content of a potential
lubricant base oil to a desired amount, a portion of the effluent
from the solvent and/or catalytic process can be exposed to an
adsorbent that is suitable for adsorption of aromatics. Exposing
only a portion of the effluent to the adsorbent can provide a
variety of advantages. For example, since only a portion of the
effluent is exposed to the adsorbent, the rate of accumulation of
aromatics can be reduced, which can increase the time required
between regeneration cycles for the adsorbent. Additionally, the
aromatics separated from the effluent via adsorption can be
captured during regeneration of the adsorbent as a separate
aromatics-enriched product stream. The portion of a lubricant base
oil exposed to an adsorbent can be any convenient amount, such as
about 20 wt % to 100 wt % of the lubricant base oil. In some
aspects, the portion of the lubricant base oil can correspond to
less than the full amount of lubricant base oil, such as about 20
wt % to about 70 wt %, and/or at least about 40 wt %, and/or about
60 wt % or less.
[0023] Suitable adsorbents can include zeolite adsorbents, such as
the NH4+ exchanged form of zeolite Beta, or Ag impregnated USY.
After adsorption of a sufficient amount of aromatics, such as about
5 wt % to about 20 wt % of aromatics relative to the weight of the
adsorbent, or about 5 wt % to about 15 wt %, or about 10 wt % to
about 15 wt %, the adsorbent can be regenerated by exposing the
adsorbent to a desorption solvent. Toluene is an example of a
suitable desorption solvent. During processing of a feed, multiple
adsorbent beds can be used so that some adsorbent beds are active
while other beds are being regenerated.
[0024] Group I basestocks or base oils are defined as base oils
with less than 90 wt % saturated molecules and/or at least 0.03 wt
% sulfur content. Group I basestocks also have a viscosity index
(VI) of at least 80 but less than 120. Group II basestocks or base
oils contain at least 90 wt % saturated molecules and less than
0.03 wt % sulfur. Group II basestocks also have a viscosity index
of at least 80 but less than 120. Group III basestocks or base oils
contain at least 90 wt % saturated molecules and less than 0.03 wt
% sulfur, with a viscosity index of at least 120. In addition to
the above formal definitions, some Group I basestocks may be
referred to as a Group I+ basestock, which corresponds to a Group I
basestock with a VI value of 103 to 108. Some Group II basestocks
may be referred to as a Group II+ basestock, which corresponds to a
Group II basestock with a VI of at least 113. Some Group III
basestocks may be referred to as a Group III+ basestock, which
corresponds to a Group III basestock with a VI value of at least
140.
[0025] In a hydroprocessing reaction system, one way of
characterizing a reaction stage is based on the stage being a
"sweet" reaction stage or a "sour" reaction stage. In this
discussion, a reaction stage where the feedstock passed into to the
stage contains at least about 500 wppm of sulfur, or at least about
1000 wppm of sulfur, can be referred to as a "sour" reaction stage.
Optionally, the reaction stage can be characterized based on the
sulfur content of both the feedstock and any treat gas passed into
the reaction stage. A sour reaction stage can be in contrast to a
"sweet" reaction stage, where the sulfur content in the feedstock
passed into the stage is about 500 wppm or less, or about 300 wppm
or less, or about 100 wppm or less, or about 50 wppm or less, or
about 15 wppm or less.
[0026] In this discussion, the severity of hydroprocessing
performed on a feed can be characterized based on an amount of
conversion of the feedstock. In various aspects, the reaction
conditions in the reaction system can be selected to generate a
desired level of conversion of a feed. Conversion of a feed is
defined in terms of conversion of molecules that boil above a
temperature threshold to molecules below that threshold. The
conversion temperature can be any convenient temperature. For
example, for a lubricant base oil production process, a suitable
conversion temperature can be from about 650.degree. F.
(343.degree. C.) to about 750.degree. F. (399.degree. C.). Unless
otherwise specified, the conversion temperature in this discussion
is a conversion temperature of 700.degree. F. (371.degree. C.).
[0027] In some aspects, using a final solvent extraction process to
achieve a desired aromatics content can allow the severity of the
initial hydroprocessing stage(s) to be reduced. For example, the
amount of conversion in the initial hydroprocessing stage can be
about 10 wt % to less than about 30 wt % relative to a conversion
temperature of 700.degree. F. (371.degree. C.). This is in contrast
to a conventional lubricant production process, which can typically
require a conversion amount of from about 30 wt % to about 50 wt %
or more.
[0028] In the discussion below, a stage can correspond to a single
reactor or a plurality of reactors. Optionally, multiple parallel
reactors can be used to perform one or more of the processes, or
multiple parallel reactors can be used for all processes in a
stage. Each stage and/or reactor can include one or more catalyst
beds containing hydroprocessing catalyst. Note that a "bed" of
catalyst in the discussion below can refer to a partial physical
catalyst bed. For example, a catalyst bed within a reactor could be
filled partially with a hydrocracking catalyst and partially with a
dewaxing catalyst. For convenience in description, even though the
two catalysts may be stacked together in a single catalyst bed, the
hydrocracking catalyst and dewaxing catalyst can each be referred
to conceptually as separate catalyst beds.
[0029] In the discussion herein, reference will be made to a
hydroprocessing reaction system. The hydroprocessing reaction
system corresponds to the one or more stages, such as two stages
and/or reactors and an optional intermediate separator, that are
used to expose a feed to a plurality of catalysts under
hydroprocessing conditions. The plurality of catalysts can be
distributed between the stages and/or reactors in any convenient
manner, with some preferred methods of arranging the catalyst
described herein.
[0030] In this discussion, the distillate fuel boiling range is
defined as 350.degree. F. (177.degree. C.) to 700.degree. F.
(371.degree. C.). Distillate fuel boiling range products can
include products suitable for use as kerosene products (including
jet fuel products) and diesel products, such as premium diesel or
winter diesel products. In this discussion, the naphtha boiling
range is defined as 36.degree. C. (97.degree. F.) to about
177.degree. C. (350.degree. F.).
Feedstocks
[0031] A wide range of petroleum and chemical feedstocks can be
hydroprocessed in accordance with the disclosure. Suitable
feedstocks include whole and reduced petroleum crudes, atmospheric
and vacuum residua, deasphalted residua, cycle oils, FCC tower
bottoms, gas oils, including vacuum gas oils and coker gas oils,
light to heavy distillates including raw virgin distillates,
hydrocrackates, hydrotreated oils, slack waxes, Fischer-Tropsch
waxes, raffinates, and mixtures of these materials.
[0032] One way of defining a feedstock is based on the boiling
range of the feed. One option for defining a boiling range is to
use an initial boiling point for a feed and/or a final boiling
point for a feed. Another option, which in some instances may
provide a more representative description of a feed, is to
characterize a feed based on the amount of the feed that boils at
one or more temperatures. For example, a "T5" boiling point for a
feed is defined as the temperature at which 5 wt % of the feed will
boil off. Similarly, a "T95" boiling point is a temperature at 95
wt % of the feed will boil.
[0033] Typical feeds include, for example, feeds with an initial
boiling point of at least about 650.degree. F. (343.degree. C.), or
at least about 700.degree. F. (371.degree. C.), or at least about
750.degree. F. (399.degree. C.). Alternatively, a feed may be
characterized using a T5 boiling point, such as a feed with a T5
boiling point of at least about 650.degree. F. (343.degree. C.), or
at least about 700.degree. F. (371.degree. C.), or at least about
750.degree. F. (399.degree. C.). In some aspects, the final boiling
point of the feed can be at least about 1100.degree. F.
(593.degree. C.), such as at least about 1150.degree. F.
(621.degree. C.) or at least about 1200.degree. F. (649.degree.
C.). In other aspects, a feed may be used that does not include a
large portion of molecules that would traditional be considered as
vacuum distillation bottoms. For example, the feed may correspond
to a vacuum gas oil feed that has already been separated from a
traditional vacuum bottoms portion. Such feeds include, for
example, feeds with a final boiling point of about 1150.degree. F.
(621.degree. C.), or about 1100.degree. F. (593.degree. C.) or
less, or about 1050.degree. F. (566.degree. C.) or less.
Alternatively, a feed may be characterized using a T95 boiling
point, such as a feed with a T95 boiling point of about
1150.degree. F. (621.degree. C.) or less, or about 1100.degree. F.
(593.degree. C.) or less, or about 1050.degree. F. (566.degree. C.)
or less. An example of a suitable type of feedstock is a wide cut
vacuum gas oil (VGO) feed, with a T5 boiling point of at least
about 700.degree. F. (371.degree. C.) and a T95 boiling point of
about 1100.degree. F. or less. Optionally, the initial boiling
point of such a wide cut VGO feed can be at least about 700.degree.
F. and/or the final boiling point can be at least about
1100.degree. F. It is noted that feeds with still lower initial
boiling points and/or T5 boiling points may also be suitable, so
long as sufficient higher boiling material is available so that the
overall nature of the process is a lubricant base oil production
process and/or a fuels hydrocracking process.
[0034] The above feed description corresponds to a potential feed
for producing lubricant base oils. In some aspects, methods are
provided for producing both fuels and lubricants. When fuels are an
additional desired product, feedstocks with lower boiling
components may also be suitable. For example, a feedstock suitable
for fuels production, such as a light cycle oil, can have a T5
boiling point of at least about 350.degree. F. (177.degree. C.),
such as at least about 400.degree. F. (204.degree. C.). Examples of
a suitable boiling range include a boiling range of from about
350.degree. F. (177.degree. C.) to about 700.degree. F.
(371.degree. C.), such as from about 390.degree. F. (200.degree.
C.) to about 650.degree. F. (343.degree. C.). Thus, a portion of
the feed used for fuels and lubricant base oil production can
include components having a boiling range from about 170.degree. C.
to about 350.degree. C. Such components can be part of an initial
feed, or a first feed with a T5 boiling point of about 650.degree.
F. (343.degree. C.) can be combined with a second feed, such as a
light cycle oil, that includes components that boil between
200.degree. C. and 350.degree. C.
[0035] Many typical feeds for production of lubricant base oils can
have a substantial sulfur content. For example, the sulfur content
of a feed prior to exposing the feed to hydroprocessing for
heteroatom removal can be at least about 300 ppm by weight of
sulfur, or at least about 500 wppm, or at least about 1000 wppm, or
at least about 2000 wppm, or at least about 4000 wppm, or at least
about 10,000 wppm, or at least about 20,000 wppm. Typical feeds can
also have substantial aromatics content. Prior to exposing the feed
to hydroprocessing, the aromatics content of a feed can be at least
about 10 wt %, or at least about 15 wt %, or at least about 20 wt
%, or at least about 30 wt %, or at least about 40 wt %. After any
catalytic processing, the aromatics content of the catalytically
processed effluent can be about 5 wt % to about 30 wt % or about 5
wt % to about 25 wt %, or about 5 wt % to about 20 wt %, or about 5
wt % to about 15 wt %, or about 10 wt % to about 30 wt %, or about
10 wt % to about 25 wt %, or about 10 wt % to about 20 wt %, or
about 10 wt % to about 15 wt %, or about 15 wt % to about 30 wt %,
or about 15 wt % to about 25 wt %, or about 15 wt % to about 20 wt
%.
[0036] In some embodiments, at least a portion of the feed can
correspond to a feed derived from a biocomponent source. In this
discussion, a biocomponent feedstock refers to a hydrocarbon
feedstock derived from a biological raw material component, from
biocomponent sources such as vegetable, animal, fish, and/or algae.
Note that, for the purposes of this document, vegetable fats/oils
refer generally to any plant based material, and can include
fat/oils derived from a source such as plants of the genus
Jatropha. Generally, the biocomponent sources can include vegetable
fats/oils, animal fats/oils, fish oils, pyrolysis oils, and algae
lipids/oils, as well as components of such materials, and in some
embodiments can specifically include one or more type of lipid
compounds. Lipid compounds are typically biological compounds that
are insoluble in water, but soluble in nonpolar (or fat) solvents.
Non-limiting examples of such solvents include alcohols, ethers,
chloroform, alkyl acetates, benzene, and combinations thereof.
[0037] In some aspects, it may be desirable to fractionate a
feedstock for lubricant base oil production so that different
portions of the feed can be processed under different conditions.
This can be one method for forming at least two lubricant base oil
products from a feedstock. For example, a suitable feedstock can be
separated to form at least a lower boiling feedstock portion, a
higher boiling feedstock portion, and a bottoms portion. Such a
separation can be performed, for example, using a vacuum
distillation unit. One method for determining the amounts in the
various portions is by selecting cut point temperatures. The cut
point temperatures may vary depending on the nature of the
feedstock. Generally, the cut point between the lower boiling
portion and the higher boiling portion can be between about
850.degree. F. (454.degree. C.) and 950.degree. F. (510.degree.
C.), such as at least about 875.degree. F. (468.degree. C.) or less
than about 925.degree. F. (496.degree. C.) or less than about
900.degree. F. (482.degree. C.). The cut point between the higher
boiling portion and the bottoms portion can be between about
1050.degree. F. (566.degree. C.) and about 1150.degree. F.
(621.degree. C.), such as less than about 1100.degree. F.
(593.degree. C.). In some alternative aspects, it may be desirable
to increase the relative amount of light neutral base oils that are
produced. In such aspects, the cut point between the lower boiling
portion and the higher boiling portion may be higher, such as at
least about 950.degree. F. (510.degree. C.), or at least about
1000.degree. F. (538.degree. C.), and less than about 1150.degree.
F. (621.degree. C.), such as less than about 1100.degree. F.
(593.degree. C.) or less than about 1050.degree. F. (566.degree.
C.).
[0038] It is noted that the above fractionation temperatures
represent the split between lighter feedstock portions, heavier
feedstock portions, and a bottoms portion. If desired, additional
fractions could also be formed based on additional cut points. For
the purposes of the discussion herein, any such additional
fractions can be processed according to boiling range. Thus, if
additional fractions are formed with a T95 boiling point of less
than about 850.degree. F. (454.degree. C.) to about 950.degree. F.
(510.degree. C.), all such additional fractions would be processed
as part of the lower boiling feedstock portion.
Hydroprocessing for Base Oil Production
[0039] After optional separation in a vacuum distillation
apparatus, a feedstock for lubricant base oil production can be
passed into a hydroprocessing reaction system. An initial stage of
the reaction system can be used for contaminant removal to produce
a hydroprocessed effluent having a sulfur content of about 100 wppm
or less, or about 50 wppm or less, or about 15 wppm or less. A
separation can then be performed to remove lower boiling portions
of the hydroprocessed effluent. This separation can remove
compounds that are gasses at standard temperature and pressure
(such as H.sub.2S, NH.sub.3, and C.sub.4-- compounds), or the
separation can remove a portion of the effluent that corresponds to
naphtha and/or distillate fuel boiling range compounds. The
remaining liquid portion of the effluent can then be catalytically
dewaxed. Due to the separation, the catalytic dewaxing step can be
performed under sweet processing conditions.
[0040] The hydroprocessing (hydrotreating and/or hydrocracking)
conditions in the reaction system can also be selected to generate
a desired level of conversion of a feed. Conversion of the feed can
be defined in terms of conversion of molecules that boil above a
temperature threshold to molecules below that threshold. The
conversion temperature can be any convenient temperature, such as
about 700.degree. F. (371.degree. C.). In an aspect, the amount of
conversion in the stage(s) of the reaction system can be selected
to enhance diesel production while achieving a substantial overall
yield of fuels. The amount of conversion can correspond to the
total conversion of molecules within a stage of the reaction system
that is used to catalytically process the feed for lubricant base
oil production. Suitable amounts of conversion of molecules boiling
above 700.degree. F. to molecules boiling below 700.degree. F.
include converting at least about 5 wt % of the 700.degree. F.+
portion of the feedstock in the hydroprocessing stage(s), or at
least about 10 wt %, or at least about 15 wt %, or at least about
20%, or at least about 25% of the 700.degree. F.+ portion.
Additionally or alternately, the amount of conversion for the
reaction system can be about 35% or less, or about 30% or less, or
about 25% or less, or about 20% or less. Still larger amounts of
conversion may also produce a suitable effluent for forming
lubricant base oils, but such higher conversion amounts will also
result in a reduced yield of lubricant base oils. Reducing the
amount of conversion can increase the yield of lubricant base oils,
but reducing the amount of conversion to below the ranges noted
above may result in a catalytically processed effluent that is not
suitable for formation of Group II or Group III lubricant base
oils. In various aspects, the catalytic dewaxing stage(s) of the
reaction system can convert about 1 wt % to about 10 wt % of feed
to the dewaxing stage(s), such as about 1 wt % to about 5 wt %.
Hydrotreatment Conditions
[0041] Heteroatoms can be removed from a feedstock under effective
hydrotreatment conditions, effective hydrocracking conditions, or a
combination thereof. Hydrotreatment is typically used to reduce the
sulfur, nitrogen, and aromatic content of a feed. The catalysts
used for hydrotreatment can include conventional hydroprocessing
catalysts, such as those that comprise at least one Group VIII
non-noble metal (Columns 8-10 of IUPAC periodic table), preferably
Fe, Co, and/or Ni, such as Co and/or Ni; and at least one Group VI
metal (Column 6 of IUPAC periodic table), preferably Mo and/or W.
Such hydroprocessing catalysts can comprise transition metal
sulfides that are impregnated or dispersed on a refractory support
or carrier such as alumina and/or silica. The support or carrier
itself typically has no significant/measurable catalytic activity.
Alternatively, the catalyst can correspond to a substantially
carrier- or support-free catalyst, commonly referred to as a bulk
catalyst.
[0042] For a supported hydrotreating catalyst, any convenient
support material can be used. In addition to alumina and/or silica,
other suitable support/carrier materials can include, but are not
limited to, zeolites, titania, silica-titania, and titania-alumina.
Suitable aluminas are porous aluminas such as gamma or eta having
average pore sizes from 50 to 200 .ANG., or 75 to 150 .ANG.; a
surface area from 100 to 300 m.sup.2/g, or 150 to 250 m.sup.2/g;
and a pore volume of from 0.25 to 1.0 cm.sup.3/g, or 0.35 to 0.8
cm.sup.3/g. More generally, any convenient size, shape, and/or pore
size distribution for a catalyst suitable for hydrotreatment of a
distillate (including lubricant base oil) boiling range feed in a
conventional manner may be used. It is within the scope of the
present disclosure that more than one type of hydroprocessing
catalyst can be used in one or multiple reaction vessels.
[0043] The at least one Group VIII non-noble metal, in oxide form,
can typically be present in an amount ranging from about 2 wt % to
about 40 wt %, preferably from about 4 wt % to about 15 wt %. The
at least one Group VI metal, in oxide form, can typically be
present in an amount ranging from about 2 wt % to about 70 wt %,
preferably for supported catalysts from about 6 wt % to about 40 wt
% or from about 10 wt % to about 30 wt %. These weight percents are
based on the total weight of the catalyst. Suitable metal catalysts
include cobalt/molybdenum (1-10% Co as oxide, 10-40% Mo as oxide),
nickel/molybdenum (1-10% Ni as oxide, 10-40% Co as oxide), or
nickel/tungsten (1-10% Ni as oxide, 10-40% W as oxide) on alumina,
silica, silica-alumina, or titania.
[0044] The hydrotreatment is carried out in the presence of
hydrogen. A hydrogen stream is, therefore, fed or injected into a
vessel or reaction zone or hydroprocessing zone in which the
hydroprocessing catalyst is located. Hydrogen, which is contained
in a hydrogen "treat gas," is provided to the reaction zone. Treat
gas, as referred to in this disclosure, can be either pure hydrogen
or a hydrogen-containing gas, which is a gas stream containing
hydrogen in an amount that is sufficient for the intended
reaction(s), optionally including one or more other gasses (e.g.,
nitrogen and light hydrocarbons such as methane), and which will
not adversely interfere with or affect either the reactions or the
products. Impurities, such as H.sub.2S and NH.sub.3 are undesirable
and would typically be removed from the treat gas before it is
conducted to the reactor. The treat gas stream introduced into a
reaction stage will preferably contain at least about 50 vol. % and
more preferably at least about 75 vol. % hydrogen, or at least
about 80 vol % hydrogen, or at least about 90 vol % hydrogen.
[0045] Effective hydrotreating conditions can include temperatures
of 200.degree. C. to 450.degree. C., or 315.degree. C. to
425.degree. C.; liquid hourly space velocities (LHSV) of 0.1
hr.sup.-1 to 10 hr.sup.-1; and hydrogen treat rates of 200 scf/B
(35.6 m.sup.3/m.sup.3) to 10,000 scf/B (1781 m.sup.3/m.sup.3), or
500 (89 m.sup.3/m.sup.3) to 5,000 scf/B (890.5 m.sup.3/m.sup.3).
With regard to pressure, the hydrotreating can be performed at a
pressure of about 300 psig (2.1 MPag) to about 1500 psig (10.4
MPag), or about 750 psig (5.2 MPag) to about 1500 psig (10.4 MPag),
or about 1000 psig (6.9 MPag) to about 1500 psig (10.4 MPag), or
about 1200 psig (8.3 MPag) to about 1500 psig (10.4 MPag).
Hydrocracking Conditions
[0046] In addition to or as an alternative to hydrotreating,
hydrocracking can be used to hydroprocess a feed for heteroatom
removal. Hydrocracking catalysts typically contain sulfided base
metals on acidic supports, such as amorphous silica alumina, acidic
zeolites such as USY, or acidified alumina. Often these acidic
supports are mixed or bound with other metal oxides such as
alumina, titania or silica. Examples of suitable acidic supports
include acidic molecular sieves, such as zeolites or
silicoaluminophophates. One example of suitable zeolite is USY,
such as a USY zeolite with cell size of 24.25 Angstroms or less.
Additionally or alternately, the catalyst can be a low acidity
molecular sieve, such as a USY zeolite with a Si to Al ratio of at
least about 20, and preferably at least about 40 or 50. Zeolite
Beta is another example of a potentially suitable hydrocracking
catalyst. Non-limiting examples of metals for hydrocracking
catalysts include metals or combinations of metals that include at
least one Group VIII metal, such as nickel,
nickel-cobalt-molybdenum, cobalt-molybdenum, nickel-tungsten,
nickel-molybdenum, and/or nickel-molybdenum-tungsten. Support
materials which may be used for can comprise a refractory oxide
material such as alumina, silica, alumina-silica, kieselguhr,
diatomaceous earth, magnesia, zirconia, or combinations thereof,
with alumina, silica, alumina-silica being the most common (and
preferred, in one embodiment). In some aspects, a hydrotreating
catalyst as described above can be exposed to a feed under
effective hydrocracking conditions to perform hydrocracking on a
feed.
[0047] In various aspects, effective hydrocracking conditions for a
hydrocracking process can include temperatures of about 550.degree.
F. (288.degree. C.) to about 840.degree. F. (449.degree. C.),
liquid hourly space velocities of from 0.05 h.sup.-1 to 10
h.sup.-1, and hydrogen treat gas rates of from 35.6 m.sup.3/m.sup.3
to 1781 m.sup.3/m.sup.3 (200 SCF/B to 10,000 SCF/B). In other
embodiments, the conditions can include temperatures in the range
of about 600.degree. F. (343.degree. C.) to about 815.degree. F.
(435.degree. C.), liquid hourly space velocities of from 0.05
h.sup.-1 to 10 h.sup.-1, and hydrogen treat gas rates of from about
213 m.sup.3/m.sup.3 to about 1068 m.sup.3/m.sup.3 (1200 SCF/B to
6000 SCF/B). With regard to pressure, the hydrocracking can be
performed at a pressure of about 300 psig (2.1 MPag) to about 1500
psig (10.4 MPag), or about 750 psig (5.2 MPag) to about 1500 psig
(10.4 MPag), or about 1000 psig (6.9 MPag) to about 1500 psig (10.4
MPag), or about 1200 psig (8.3 MPag) to about 1500 psig (10.4
MPag).
Catalytic Dewaxing Process
[0048] After hydrotreating and/or hydrocracking for heteroatom
removal, at least a (liquid) portion of the resulting effluent can
be catalytically dewaxed for improvement of pour point and/or other
cold flow properties. Suitable dewaxing catalysts can include
molecular sieves such as crystalline aluminosilicates (zeolites).
In some aspects, any conventional dewaxing catalyst can be used. In
other aspects, the molecular sieve can comprise, consist
essentially of, or be ZSM-5, ZSM-22, ZSM-23, ZSM-35, ZSM-48,
zeolite Beta, or a combination thereof, for example ZSM-23 and/or
ZSM-48, or ZSM-48 and/or zeolite Beta. Optionally but preferably,
molecular sieves that are selective for dewaxing by isomerization
as opposed to cracking can be used, such as ZSM-48, zeolite Beta,
ZSM-23, or a combination thereof. Additionally or alternately, the
molecular sieve can comprise, consist essentially of, or be a
10-member ring 1-D molecular sieve. Examples include EU-1, ZSM-35
(or ferrierite), ZSM-11, ZSM-57, NU-87, SAPO-11, ZSM-48, ZSM-23,
and ZSM-22. Preferred materials are EU-2, EU-11, ZBM-30, ZSM-48, or
ZSM-23. ZSM-48 is most preferred. Note that a zeolite having the
ZSM-23 structure with a silica to alumina ratio of from about 20:1
to about 40:1 can sometimes be referred to as SSZ-32. Other
molecular sieves that are isostructural with the above materials
include Theta-1, NU-10, EU-13, KZ-1, and NU-23. Optionally but
preferably, the dewaxing catalyst can include a binder for the
molecular sieve, such as alumina, titania, silica, silica-alumina,
zirconia, or a combination thereof, for example alumina and/or
titania or silica and/or zirconia and/or titania.
[0049] Preferably, the dewaxing catalysts used in processes
according to the disclosure are catalysts with a low ratio of
silica to alumina. For example, for ZSM-48, the ratio of silica to
alumina in the zeolite can be less than about 200:1, such as less
than about 110:1, or less than about 100:1, or less than about
90:1, or less than about 75:1. In various embodiments, the ratio of
silica to alumina can be from 50:1 to 200:1, such as 60:1 to 160:1,
or 70:1 to 100:1.
[0050] In various embodiments, the catalysts according to the
disclosure further include a metal hydrogenation component. The
metal hydrogenation component is typically a Group VI and/or a
Group VIII metal. Preferably, the metal hydrogenation component is
a Group VIII noble metal. Preferably, the metal hydrogenation
component is Pt, Pd, or a mixture thereof. In an alternative
preferred embodiment, the metal hydrogenation component can be a
combination of a non-noble Group VIII metal with a Group VI metal.
Suitable combinations can include Ni, Co, or Fe with Mo or W,
preferably Ni with Mo or W.
[0051] The metal hydrogenation component may be added to the
catalyst in any convenient manner. One technique for adding the
metal hydrogenation component is by incipient wetness. For example,
after combining a zeolite and a binder, the combined zeolite and
binder can be extruded into catalyst particles. These catalyst
particles can then be exposed to a solution containing a suitable
metal precursor. Alternatively, metal can be added to the catalyst
by ion exchange, where a metal precursor is added to a mixture of
zeolite (or zeolite and binder) prior to extrusion.
[0052] The amount of metal in the catalyst can be at least 0.1 wt %
based on catalyst, or at least 0.15 wt %, or at least 0.2 wt %, or
at least 0.25 wt %, or at least 0.3 wt %, or at least 0.5 wt %
based on catalyst. The amount of metal in the catalyst can be 20 wt
% or less based on catalyst, or 10 wt % or less, or 5 wt % or less,
or 2.5 wt % or less, or 1 wt % or less. For embodiments where the
metal is Pt, Pd, another Group VIII noble metal, or a combination
thereof, the amount of metal can be from 0.1 to 5 wt %, preferably
from 0.1 to 2 wt %, or 0.25 to 1.8 wt %, or 0.4 to 1.5 wt %. For
embodiments where the metal is a combination of a non-noble Group
VIII metal with a Group VI metal, the combined amount of metal can
be from 0.5 wt % to 20 wt %, or 1 wt % to 15 wt %, or 2.5 wt % to
10 wt %.
[0053] Process conditions in a catalytic dewaxing zone can include
a temperature of from 200 to 450.degree. C., preferably 270 to
400.degree. C., an LHSV from about 0.2 h.sup.-1 to about 10
h.sup.-1, such as from about 0.5 h.sup.-1 to about 5 h.sup.-1, and
a treat gas rate of from 35.6 m.sup.3/m.sup.3 (200 SCF/B) to 1781
m.sup.3/m.sup.3 (10,000 scf/B), preferably 178 m.sup.3/m.sup.3
(1000 SCF/B) to 890.6 m.sup.3/m.sup.3 (5000 SCF/B). With regard to
pressure, the dewaxing can be performed at a pressure of about 300
psig (2.1 MPag) to about 700 psig (4.8 MPag), or about 300 psig
(2.1 MPag) to about 600 psig (4.2 MPag), or about 300 psig (2.1
MPag) to about 500 psig (3.5 MPag), or about 400 psig (2.8 MPag) to
about 700 psig (4.8 MPag), or about 400 psig (2.8 MPag) to about
600 psig (4.2 MPag), or about 400 psig (2.8 MPag) to about 500 psig
(3.5 MPag), or about 500 psig (3.5 MPag) to about 700 psig (4.8
MPag).
Hydrofinishing and/or Aromatic Saturation Process
[0054] In some optional aspects, a hydrofinishing and/or aromatic
saturation stage can also be provided. If a solvent extraction
stage is present for aromatics removal, then typically a
hydrofinishing stage will not be included. However, a
hydrofinishing stage may be desirable if the final aromatics
removal step is via adsorption rather than by solvent
extraction.
[0055] Hydrofinishing and/or aromatic saturation catalysts can
include catalysts containing Group VI metals, Group VIII metals,
and mixtures thereof. In an embodiment, preferred metals include at
least one metal sulfide having a strong hydrogenation function. In
another embodiment, the hydrofinishing catalyst can include a Group
VIII noble metal, such as Pt, Pd, or a combination thereof. The
mixture of metals may also be present as bulk metal catalysts
wherein the amount of metal is about 30 wt. % or greater based on
catalyst. Suitable metal oxide supports include low acidic oxides
such as silica, alumina, silica-aluminas or titania, preferably
alumina. The preferred hydrofinishing catalysts for aromatic
saturation will comprise at least one metal having relatively
strong hydrogenation function on a porous support. Typical support
materials include amorphous or crystalline oxide materials such as
alumina, silica, and silica-alumina. The support materials may also
be modified, such as by halogenation, or in particular
fluorination. The metal content of the catalyst is often as high as
about 20 weight percent for non-noble metals. In an embodiment, a
preferred hydrofinishing catalyst can include a material belonging
to the M41S class or family of catalysts. The M41S family of
catalysts are mesoporous materials having high silica content.
Examples include MCM-41, MCM-48 and MCM-50. A preferred member of
this class is MCM-41. If separate catalysts are used for aromatic
saturation and hydrofinishing, an aromatic saturation catalyst can
be selected based on activity and/or selectivity for aromatic
saturation, while a hydrofinishing catalyst can be selected based
on activity for improving product specifications, such as product
color and polynuclear aromatic reduction.
[0056] Hydrofinishing conditions can include temperatures from
about 125.degree. C. to about 425.degree. C., preferably about
180.degree. C. to about 280.degree. C., a hydrogen partial pressure
from about 500 psig (3.4 MPa) to about 3000 psig (20.7 MPa),
preferably about 1500 psig (10.3 MPa) to about 2500 psig (17.2
MPa), and liquid hourly space velocity from about 0.1 hr.sup.-1 to
about 5 hr.sup.-1 LHSV, preferably about 0.5 hr.sup.-1 to about 1.5
hr.sup.-1. Additionally, a hydrogen treat gas rate of from 35.6
m.sup.3/m.sup.3 to 1781 m.sup.3/m.sup.3 (200 SCF/B to 10,000 SCF/B)
can be used.
Solvent Extraction for Aromatics Removal
[0057] Solvent extraction can be used to reduce the aromatics
content and/or the amount of polar molecules in the hydroprocessed,
dewaxed effluent. The solvent extraction process selectively
dissolves aromatic components to form an aromatics-rich extract
phase while leaving the more paraffinic components in an
aromatics-poor raffinate phase. Naphthenes are distributed between
the extract and raffinate phases. Typical solvents for solvent
extraction include phenol, furfural and N-methyl pyrrolidone. More
generally, any convenient solvent for removing aromatics to about
2.5 wt % or less, or about 1.5 wt % or less, or about 1.0 wt % or
less, can be used. However, use of those solvents most selective
for removing aromatics, such as SO.sub.2, sulfolane, and DMSO, can
maximize both yield of the raffinate and concentration of aromatics
in the extract phase. Such selective solvents, by accentuating the
difference in density between the dispersed and continuous phases,
tend to overcome low rates in the coalescence step of the
extraction process. By controlling the solvent to oil ratio,
extraction temperature, content of water or other solvency
modifier, temperature gradient in the liquid-liquid treater tower,
and method of contacting hydroprocessed, dewaxed effluent to be
extracted with solvent, one can further control the degree of
separation between the extract and raffinate phases. Any convenient
type of liquid-liquid extractor can be used, such as a
counter-current liquid-liquid extractor.
[0058] In various aspects, a suitable extraction solvent can have
one or more of the following characteristics, such as two or more,
or three or more, or four or more, or all of the characteristics.
One characteristic can be a high polarity or high dipole moment. A
solvent with a high polarity can often correspond to a solvent with
a high boiling point and/or a high dipole moment. Another
characteristic can be thermal and/or chemical stability under the
solvent extraction conditions, which can involve elevated
temperatures. Still another characteristic can be suitable
miscibility with water, with organic solvents, or a combination
thereof. Yet another characteristic can be a solvent which presents
a reduced or minimized hazard from a fire and/or toxicological
standpoint. In other words, the solvent can have properties such as
a high flash point temperature (thereby reducing or minimizing fire
hazard) or a low corrosiveness (thereby reducing or minimizing
toxicological hazard). Still another desirable solvent
characteristic can be to have a solvent that is substantially free
of contaminants, such as a solvent with a purity of at least about
95 vol %, or at least about 99 vol %.
[0059] Examples of solvents that correspond to one or more of the
above characteristics can include, but are not limited to, methyl
pyrollidone (NMP), furfural, phenol, SO.sub.2, sulfolane,
dimethylsulfoxide, or combinations thereof. In some aspects, a
solvent can further contain a solvency modifier, such as water.
Example of Configuration for Integrated Reaction System
[0060] FIG. 1 shows a schematic example of configuration for
forming lubricant base oils using both catalytic processing and
solvent processing. In the configuration shown in FIG. 1, a
feedstock for lubricant base oil production 105 is introduced into
a vacuum distillation tower 110. The vacuum distillation tower 110
fractionates the feedstock 105 into at least a portion 115 suitable
for further processing to form a lubricant base oil. The feedstock
portion 115 is then hydroprocessed 120 (i.e., hydrotreated and/or
hydrocracked) to form a hydroprocessed effluent 125. The
hydroprocessed effluent 125 can be separated (not shown) to remove
at least gas phase heteroatom contaminants generated during
hydroprocessing, such as H.sub.2S and NH.sub.3. A remaining portion
of the hydroprocessed effluent 125, such as a liquid portion, can
then be catalytically dewaxed 130 to form a hydroprocessed, dewaxed
effluent 135. The hydroprocessed, dewaxed effluent 135 can then be
solvent extracted 140. This results in an aromatics-rich extract
148 and a raffinate 145 with reduced aromatics content. The
raffinate 145 can have an aromatics content of less than about 2.5
wt %, or less than about 1.5 wt %, or less than about 1.0 wt %,
making the raffinate suitable for use as a Group II or Group III
lubricant base oil, optionally after further hydrofinishing. The
aromatics-rich extract 148 represents a high quality extract
product based on the low sulfur content. Additionally, it is
believed that the extract 148 can have a narrower distribution of
carbon atoms per molecule and be more stable to oxidative and
thermal degradation than a typical extract derived from solvent
processing to form a Group I base oil.
[0061] It is noted that after hydroprocessing, the order of
performing additional processes on the hydroprocessed effluent 125
can be any one of a variety of convenient orderings. For example,
the configuration in FIG. 1 shows a liquid portion of
hydroprocessed effluent 125 being catalytically dewaxed 130. This
produces a hydroprocessed, dewaxed effluent 135 which is then
solvent extracted 140. As an alternative (not shown), the liquid
portion of the hydroprocessed effluent 125 can be solvent extracted
140 to produce an aromatics-rich extract and a raffinate with a
reduced aromatics content. The hydroprocessed raffinate can then be
catalytically dewaxed to produce a dewaxed effluent that is
suitable for use as a Group II or Group III lubricant base oil,
optionally after further hydrofinishing. The aromatics-rich extract
generated in this alternative configuration can have properties
similar to those described above for aromatics-rich extract 148 in
the configuration shown in FIG. 1.
Example 1
Solvent Extraction of a Catalytically Processed Lubricant Base Oil
Feed
[0062] In the following example, a solvent extraction process was
modeled for an example of a lubricant base oil feed. The modeled
feed corresponded to an output stream from a hydrocracking process.
The feed contained 24% aromatics and had a density @ 15.degree. C.
of 0.8895 g/cc. The D2887 boiling points of the feed were between
340.degree. C. (IBP) to 600.degree. C. (FBP). The modeled feed did
not include sulfur or nitrogen.
[0063] An empirical-based model was then used to determine the
output streams from performing an aromatic extraction process on
the modeled feed under various extraction conditions. In the
modeled extraction, an extractor was used that had 5 to 10
theoretical stages. In the modeled extraction, the dosage solvent
was between 300 to 500 vol % of the feed, the water in the solvent
was between 0.5 to 1.5 wt %, the temperature gradient was between 5
to 10.degree. C., and the bottom temperature was between 75 to
90.degree. C. The extraction was based on use of n-methyl
pyrollidone (NMP) as the solvent. The modeled results showed an
aromatic content in the raffinate of between .about.0.5% to 1.7%
depending on the conditions.
Example 2
Comparison with Conventional Catalytic Processing
[0064] The following example provides a qualitative yield and
product comparison between a conventional configuration and a
process for combined catalytic and solvent processing.
[0065] For a typical commercial Group II lubricant base oil
production process, a hydrocracking unit can be operated between
2000 psig and 3000 psig pressure. This typically results in
conversion of around 50 wt % of the feedstock relative to a
700.degree. F. conversion temperature. The hydrocracked feed can
then be dewaxed in the presence of a dewaxing catalyst. Some
typical Group II lubricant base oil production process can have
about 5 wt % conversion in the catalytic dewaxing process. As an
example, a typical expected lube production yield for such a
conventional configuration can be about 47.5 vol % based on the
volume of feed passed into the hydrocracking unit.
[0066] In some aspects, a hydrocracking and/or hydrotreating
process can be used to hydroprocess a feed for lubricant base oil
production to reduce the sulfur and nitrogen contents of the feed.
The hydrocracking and/or hydrotreating process can also provide
some increase in viscosity index for the eventual lubricant base
oil process. However, because solvent extraction will be used for
aromatics reduction, the conversion in the hydrocracking and/or
hydrotreating stage can be lower than a conventional process. For
example, the conversion in the hydroprocessing stage relative to a
conversion temperature of 700.degree. F. can be about 30 wt % or
less. The hydroprocessed effluent (or at least a portion of the
effluent) can then be catalytically dewaxed. This can result in
about 5 wt % conversion of the hydroprocessed effluent, which is
similar to the conversion in the dewaxing stage of a conventional
process. The hydroprocessed, dewaxed effluent can then be solvent
extracted to produce an aromatics-rich extract and a raffinate with
a reduced aromatics content of about 2.5 wt % or less, or about 1.5
wt % or less, or about 1.0 wt % or less. The extraction unit can
also improve the stability of the lubricant base oil product by
removing polynuclear aromatics (PNAs). The total lube production
for this configuration can be about 33 vol % relative to the feed
to the hydroprocessing stage. However, the aromatics-rich extract
stream produced in this configuration can also have a volume of
about 33 vol % relative to the feed to the hydroprocessing stage.
The aromatics-rich extract stream can be a premium stream since it
will have low sulfur and nitrogen content and less aromatic than
traditional extract streams formed during processing of a Group I
lubricant base oil. In addition, this extract will be more stable
and have a more narrow carbon distribution composition than
traditional extracts of Group I lube production.
[0067] In an alternative aspect where the hydroprocessing stage
corresponds to a hydrotreating stage, the conversion can be about
15 wt % or less, or about 10 wt % or less. Use of this type of
alternative can be dependent on the nature of the initial feedstock
available in a refinery. In this type of alternative, assuming a
50% efficiency in the solvent extraction unit(s), the overall yield
can be about 43 vol % of Group II quality lubricant base oil, with
a similar amount of premium aromatics-rich extract.
Example 3
Adsorbents for Aromatics Removal
[0068] In some alternative aspects, methods are also provided for
using an adsorbent to remove aromatics from a catalytically
processed lubricant base oil product while also generating an
aromatics-rich side product. In such aspects, a portion of a
lubricant base oil product can be passed through an adsorbent to
remove aromatics. The aromatics-depleted portion can then be
recombined with the remaining portion so that the overall product
has a desired aromatics content. As an example, a lubricant base
oil production process may generate 35 kilobarrels per day (kbd) of
lubricant base oil. A portion of this production, such as 20 kbd,
can be passed through the adsorbent. The adsorbent can be effective
for reducing the aromatics concentration of the 20 kbd portion to a
low level, such as less than about 500 wppm, or less than about 100
wppm. The aromatics-lean portion of the lubricant base oil can then
be recombined with the remaining 15 kbd of the lubricant base oil.
If the original aromatics content was, for example, about 7 wt %,
the final lubricant base oil can have an aromatics content of about
3 wt %.
[0069] An advantage of the adsorbent process is that the adsorbent
can be used as needed. For example, at the beginning of a
processing run, the aromatics content of the lubricant base oil may
be within a desired specification. As one or more catalysts
deactivate, the aromatics content may increase. The adsorbent can
then be used on a portion of the lubricant base oil product to
maintain a desired specification.
[0070] After a period of adsorption, the adsorbent may reach a
maximum desired loading of aromatics. This can correspond to, for
example, about 10 wt % to about 20 wt % of aromatics relative to
the weight of the adsorbent. The adsorbent vessel can then be taken
off-line to allow for regeneration. The regeneration can be
performed by passing a desorption solvent through the adsorbent,
such as toluene. The aromatics concentrate produced during the
desorption cycle can be sent to an extraction unit as feed to
recover all the remaining paraffinic molecules or also as feed to
Treated Distillate Aromatic Extract for the tire or asphalt
industry or used as a solvency additive.
[0071] FIG. 2 schematically shows a configuration for using an
adsorbent as part of a process for making a lubricant base oil. In
FIG. 2, a portion of a lubricant base oil product 205 is passed
into an adsorbent vessel. In the configuration shown in FIG. 2,
either adsorbent vessel 240 or 241 can be in use for adsorption at
any given time. During adsorption from a lubricant base oil,
passing the portion of lubricant base oil product 205 through the
adsorbent vessel (such as adsorbent vessel 240) produces an
aromatics-lean product 215. The aromatics-lean product 215 can then
be combined with the remaining portion of the lubricant base oil
(not shown).
[0072] While an adsorbent vessel is not in use for adsorption, such
as adsorbent vessel 241, at least a portion of the time can be used
for regenerating the adsorbent vessel. In the configuration shown
in FIG. 2, during a regeneration cycle, a fresh stream of
desorption solvent 222 can be passed into adsorbent vessel 241.
This results in desorption of aromatics from the adsorbent in
vessel 241 to form an aromatics extract stream 245. A surge tank
250 can be used to control the flow of aromatics extract stream 245
to fractionator or stripper 260. The fractionator 260 can be used
to separate the aromatics extract from the desorption solvent,
resulting in formation of an aromatic concentration stream 265 and
a recycled desorption solvent stream 262.
[0073] The adsorption methods described herein can generally be
used with any lubricant base oil product where a partial reduction
of aromatics content is desired. The adsorbent can be any adsorbent
that is selective for adsorption of aromatics relative to paraffins
and naphthenes. Molecular sieves can be suitable adsorbents, such
as zeolite H-Beta and Ag/USY or other zeolites (5A, 13X, MCM-22,
MCM-68 and ZSM-5). The absorbents could also include active
carbons, mesoporous silica, M41S family of materials, sulfonated
polymers such as Amberlyst acid ion exchanged resin, Nafion, It is
believe that adsorption primarily occurs on the surface and
temperature may influence the diffusion of large aromatic molecules
through viscous liquids. Key parameters of desirable adsorbent are
related to acidity, pore size and mesoporous/macroporous nature. A
metal cation modified adsorbent may also impact on
capacity/separation factor of aromatic adsorption. Some suitable
metals cations can include, but are not limited to, Ag+, Na+, Ca2+,
and Cu+. In this discussion, a metal cation can be identified by
simply referring to a cation of the corresponding metal, such as by
referring to a cation of Ag, Na, Ca, or Cu, without explicitly
reciting an oxidation state.
[0074] The adsorption and desorption processes can be performed at
temperatures from about 80.degree. C. to about 300.degree. C. The
amount of desorption solvent can be about 1 g of solvent per g of
adsorbent used. As a comparison, each kg of adsorbent is suitable
for treating about 2000 barrels of lubricant base oil.
Example 4
Adsorption of a Catalytically Processed Lubricant Base Oil Feed
[0075] In the following example, an adsorption process was applied
for making a lubricant base oil feed with improved saturate
content. The hydroprocessed and dewaxed feed corresponded to an
output stream from a hydrocracking/dewaxing process. These feed
properties are summarized in the table below.
TABLE-US-00001 TABLE 1 Properties of a lube basestock to be treated
via adsorption: Property (Test Method) Result Result KV100, KV40
(D445) 5.28 cSt, 29.26 cSt 5.3 cSt, 29.1 cSt Density (D4052) 0.8527
g/mL 0.854 g/mL Flashpoint (D92) 226.degree. C. 218.degree. C.
Total Aromatics (M1514) 63.12 86 (mmol/kg) 1+ Ring, mmol/kg 53.8
73.3 2+ Ring, mmol/kg 6.96 9.8 3+ Ring, mmol/kg 0.57 1.1 4+ Ring,
mmol/kg 1.99 2.9
[0076] As the first pass of adsorbent screening, 3 g of feed was
charged into a batch multi-wells unit with varied adsorbent
loadings (100 mg to 800 mg). Various absorbents were tested with 24
hours run-length at 30.degree. C. The liquid product was recovered
and submitted for aromatics measurement by UV-Vis. In adsorption
data analysis, lube basestock feed was taken as a binary mixture
containing all aromatic molecules lumped together as a single
entity and non-aromatic molecules being the other component. The
capacity and selectivity of adsorbent were calculated using direct
experimental measurements of total moles & composition of
liquid before and after contact with adsorbent, and adsorbent
loading. These two adsorption parameters are defined as the
adsorption separation factor (S12) and the adsorbent capacity (g
aromatic adsorbed/100 g Adsorbent). Over a group of adsorbents
screened using the static experiments, H-Beta and 5 wt % Ag/USY
showed preferential adsorption of aromatic molecules over
saturates. As shown is FIG. 3, maximum average separation factor
S12 was significant for H-Beta and 5 wt % Ag/USY. For H-Beta and 5
wt % Ag/USY, the S12 for 1-ring aromatic molecules over saturates
was observed to be .about.9-10. The adsorbent capacity for H-Beta
and 5 wt % Ag/USY was also determined to be .about.4, as
illustrated in FIG. 4.
[0077] Any convenient cycle can be used for adsorption and/or
regeneration. For example, adsorption of aromatics can be performed
by filling the adsorbent vessel, holding the base oil in the vessel
for a period of time, emptying the vessel, filling the vessel with
the desorption solvent, and then holding the desorption solvent for
a period of time. Using this type of schedule, the empty/fill
portion of the schedule can correspond to about 30 minutes, while
the holding time (for lubricant base oil or for desorption solvent)
can be about 2 hours. The adsorption and/or desorption processes
can be performed at isothermal (approximately constant temperature)
or non-isothermal conditions.
Additional Embodiments
Embodiment 1
[0078] A method for forming a lubricant base stock, comprising:
hydroprocessing a feedstock having a T5 boiling point greater than
about 600.degree. F. (316.degree. C.) and a sulfur content of at
least about 500 wppm under effective hydroprocessing conditions to
form a hydroprocessed effluent, the effective hydroprocessing
conditions including a total pressure of less than about 1500 psig
(10.3 MPag); separating the hydroprocessed effluent to form at
least a gas phase effluent and a hydroprocessed liquid product
effluent having a sulfur content of less than 500 wppm; dewaxing at
least a first portion of the hydroprocessed liquid product effluent
to form a dewaxed effluent; extracting at least a second portion of
the hydroprocessed liquid product effluent in the presence of an
extraction solvent to form a raffinate product and an extract
product, the raffinate product having a sulfur content of about 300
wppm or less; and fractionating at least a portion of the raffinate
product to form at least a lubricant base stock product having a
viscosity index of at least about 80, and an aromatics content of
about 3.0 wt % or less, or about 2.5 wt % or less, or about 2.0 wt
% or less, or about 1.5 wt % or less, or about 1.0 wt % or
less.
Embodiment 2
[0079] The method of Embodiment 1, further comprising hydrofining
at least a portion of the raffinate product under effective
hydrofining conditions to form a hydrofined raffinate, wherein
dewaxing at least a first portion of the hydroprocessed liquid
product effluent comprises solvent dewaxing at least a portion of
the hydrofined raffinate.
Embodiment 3
[0080] The method of Embodiment 1, wherein dewaxing at least a
first portion of the hydroprocessed liquid product effluent
comprises exposing the at least a first portion of the
hydroprocessed liquid product effluent to a dewaxing catalyst under
effective catalytic dewaxing conditions to form the dewaxed
effluent, the effective catalytic dewaxing conditions including a
total pressure of about 300 psig (2.1 MPag) to about 700 psig (4.8
MPag), wherein extracting at least a second portion of the
hydroprocessed liquid product effluent comprises extracting at
least a portion of the dewaxed effluent.
Embodiment 4
[0081] A method for forming a lubricant base stock, comprising:
hydroprocessing a feedstock having a T5 boiling point greater than
about 600.degree. F. (316.degree. C.) and a sulfur content of at
least about 500 wppm under effective hydroprocessing conditions to
form a hydroprocessed effluent, the effective hydroprocessing
conditions including a total pressure of less than about 1500 psig
(10.3 MPag); separating the hydroprocessed effluent to form at
least a gas phase effluent and a hydroprocessed liquid product
effluent having a sulfur content of less than 500 wppm; exposing at
least a portion of the hydroprocessed liquid product effluent to a
dewaxing catalyst under effective catalytic dewaxing conditions to
form a dewaxed effluent, the effective catalytic dewaxing
conditions including a total pressure of about 300 psig (2.1 MPag)
to about 700 psig (4.8 MPag); extracting at least a portion of the
dewaxed effluent in the presence of an extraction solvent to form a
raffinate product and an extract product, the raffinate product
having a sulfur content of about 300 wppm or less; and
fractionating at least a portion of the raffinate product to form
at least a lubricant base stock product having a viscosity index of
at least about 80, and an aromatics content of about 3.0 wt % or
less, or about 2.5 wt % or less, or about 2.0 wt % or less, or
about 1.5 wt % or less, or about 1.0 wt % or less.
Embodiment 5
[0082] The method of Embodiments 3 or 4, wherein the effective
dewaxing conditions comprise a total pressure of about 300 psig
(2.1 MPag) to about 600 psig (4.2 MPag), or about 300 psig (2.1
MPag) to about 500 psig (3.5 MPag), or about 400 psig (2.8 MPag) to
about 700 psig (4.8 MPag), or about 400 psig (2.8 MPag) to about
600 psig (4.2 MPag), or about 400 psig (2.8 MPag) to about 500 psig
(3.5 MPag), or about 500 psig (3.5 MPag) to about 700 psig (4.8
MPag), the effective dewaxing conditions optionally being effective
for conversion of about 1 wt % to about 10 wt % of the at least a
portion of the hydroprocessed liquid product effluent, or about 1
wt % to about 5 wt %.
Embodiment 6
[0083] The method of any of Embodiments 3 to 5, wherein the dewaxed
effluent has an aromatics content of about 5 wt % to about 30 wt %
or about 5 wt % to about 25 wt %, or about 5 wt % to about 20 wt %,
or about 5 wt % to about 15 wt %, or about 10 wt % to about 30 wt
%, or about 10 wt % to about 25 wt %, or about 10 wt % to about 20
wt %, or about 10 wt % to about 15 wt %, or about 15 wt % to about
30 wt %, or about 15 wt % to about 25 wt %, or about 15 wt % to
about 20 wt %.
Embodiment 7
[0084] The method of any of the above embodiments, further
comprising hydrofinishing at least a portion of the dewaxed
effluent under effective hydrofinishing conditions.
Embodiment 8
[0085] The method of any of the above embodiments, wherein
fractionating the at least a portion of the raffinate product
further comprises forming a distillate boiling range product.
Embodiment 9
[0086] The method of any of the above embodiments, further
comprising separating the dewaxed effluent to form a fraction
having a T5 boiling point of at least about 500.degree. F. and at
least one fuel product, the at least one fuel product being a
naphtha boiling range product or a distillate fuel boiling range
product, wherein extracting at least a portion of the dewaxed
effluent comprises extracting at least a portion of the fraction
having a T5 boiling point of at least about 500.degree. F.
(260.degree. C.).
Embodiment 10
[0087] The method of any of the above embodiments, wherein
separating the hydroprocessed effluent further comprises forming at
least one fuel product, the at least one fuel product being a
naphtha boiling range product or a distillate fuel boiling range
product.
Embodiment 11
[0088] The method of any of the above embodiments wherein the
effective hydroprocessing conditions comprise a total pressure of
about 300 psig (2.1 MPag) to about 1500 psig (10.4 MPag), or about
750 psig (5.2 MPag) to about 1500 psig (10.4 MPag), or about 1000
psig (6.9 MPag) to about 1500 psig (10.4 MPag), or about 1200 psig
(8.3 MPag) to about 1500 psig (10.4 MPag), the hydroprocessed
liquid product effluent optionally having a sulfur content of about
100 wppm or less, or about 50 wppm or less, or about 15 wppm or
less.
Embodiment 12
[0089] The method of any of the above embodiments, wherein the
effective hydroprocessing conditions comprise effective
hydrotreating conditions, effective hydrocracking conditions, or a
combination thereof, the effective hydroprocessing conditions
optionally being effective for conversion of about 5 wt % to about
30 wt % of the feedstock having a T5 boiling point greater than
about 600.degree. F. (316.degree. C.) relative to a conversion
temperature of about 700.degree. F. (371.degree. C.), or about 10
wt % to about 25 wt %, or about 10 wt % to about 20 wt %, or about
5 wt % to about 15 wt %, or about 5 wt % to about 10 wt %.
Embodiment 13
[0090] The method of any of the above embodiments, wherein the
extraction solvent comprises methyl pyrollidone (NMP), furfural,
phenol, SO.sub.2, sulfolane, dimethylsulfoxide, or a combination
thereof.
Embodiment 14
[0091] A method for forming a lubricant base stock, comprising:
hydroprocessing a feedstock having a T5 boiling point greater than
about 600.degree. F. (316.degree. C.) and a sulfur content of at
least about 500 wppm under effective hydroprocessing conditions to
form a hydroprocessed effluent; exposing at least a portion of the
hydroprocessing effluent to a dewaxing catalyst under effective
catalytic dewaxing conditions to form a hydroprocessed, dewaxed
effluent, the hydroprocessed, dewaxed effluent comprising a
lubricant base oil fraction having an aromatics content of at least
about 3 wt %, the lubricant base oil fraction including a first
lubricant base oil portion and a second lubricant base oil portion;
exposing the first lubricant base oil portion to an adsorbent to
form an aromatics-depleted first lubricant base oil portion, the
first lubricant base oil portion comprising about 20 wt % to about
70 wt % of the lubricant base oil fraction, an aromatics content of
the aromatics-depleted first lubricant base oil portion being about
500 wppm or less; and combining the aromatics-depleted first
lubricant base oil portion with the second lubricant base oil
portion.
Embodiment 15
[0092] The method of Embodiment 14, wherein the adsorbent comprises
one or more of zeolites, active carbon, mesoporous silica,
materials corresponding to the M41S family of materials, and
sulfonated polymers, the adsorbent optionally comprising one or
more of zeolite Beta, USY, zeolite 5A, zeolite 13X, MCM-22, MCM-68,
ZSM-5, MCM-41, Amberlyst acid ion exchanged resin and Nafion, the
adsorbent optionally further comprising metal cations, the metal
cations optionally comprising cations of Ag, Na, Ca, Cu, or a
combination thereof.
Embodiment 16
[0093] The method of Embodiments 14 or 15, further comprising
exposing the adsorbent to a desorption solvent to form an aromatics
extract fraction.
Embodiment 17
[0094] The method of any of Embodiments 14 to 16, further
comprising hydrofinishing at least a portion of the hydroprocessed,
dewaxed effluent to form a hydrofinished effluent, the
hydrofinished effluent comprising the lubricant base oil
fraction.
[0095] When numerical lower limits and numerical upper limits are
listed herein, ranges from any lower limit to any upper limit are
contemplated. While the illustrative embodiments of the disclosure
have been described with particularity, it will be understood that
various other modifications will be apparent to and can be readily
made by those skilled in the art without departing from the spirit
and scope of the disclosure. Accordingly, it is not intended that
the scope of the claims appended hereto be limited to the examples
and descriptions set forth herein but rather that the claims be
construed as encompassing all the features of patentable novelty
which reside in the present disclosure, including all features
which would be treated as equivalents thereof by those skilled in
the art to which the disclosure pertains.
[0096] The present disclosure has been described above with
reference to numerous embodiments and specific examples. Many
variations will suggest themselves to those skilled in this art in
light of the above detailed description. All such obvious
variations are within the full intended scope of the appended
claims.
* * * * *