U.S. patent application number 16/359403 was filed with the patent office on 2019-07-18 for block processing configurations for base stock production from deasphalted oil.
The applicant listed for this patent is ExxonMobil Research and Engineering Company. Invention is credited to Michael B. CARROLL, Adrienne R. DIEBOLD, Kendall S. FRUCHEY, Camden N. HE NDERSON, Timothy L. HILBERT, Lisa I-Ching YEH.
Application Number | 20190218465 16/359403 |
Document ID | / |
Family ID | 59270182 |
Filed Date | 2019-07-18 |
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United States Patent
Application |
20190218465 |
Kind Code |
A1 |
FRUCHEY; Kendall S. ; et
al. |
July 18, 2019 |
BLOCK PROCESSING CONFIGURATIONS FOR BASE STOCK PRODUCTION FROM
DEASPHALTED OIL
Abstract
Systems and methods are provided for block operation during
lubricant and/or fuels production from deasphalted oil. During
"block" operation, a deasphalted oil and/or the hydroprocessed
effluent from an initial processing stage can be split into a
plurality of fractions. The fractions can correspond, for example,
to feed fractions suitable for forming a light neutral fraction, a
heavy neutral fraction, and a bright stock fraction, or the
plurality of fractions can correspond to any other convenient split
into separate fractions. The plurality of separate fractions can
then be processed separately in the process train (or in the sweet
portion of the process train) for forming fuels and/or lubricant
base stocks. The separate processing can allow for selection of
conditions for forming lubricant fractions, such as bright stock
fractions, that have a cloud point that is lower than the pour
point.
Inventors: |
FRUCHEY; Kendall S.;
(Easton, PA) ; CARROLL; Michael B.; (Center
Valley, PA) ; HILBERT; Timothy L.; (Middleburg,
VA) ; DIEBOLD; Adrienne R.; (Lebanon, NJ) ;
YEH; Lisa I-Ching; (Marlton, NJ) ; HE NDERSON; Camden
N.; (Mullica Hill, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ExxonMobil Research and Engineering Company |
Annandale |
NJ |
US |
|
|
Family ID: |
59270182 |
Appl. No.: |
16/359403 |
Filed: |
March 20, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15631620 |
Jun 23, 2017 |
10287516 |
|
|
16359403 |
|
|
|
|
62439943 |
Dec 29, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10M 171/02 20130101;
B01J 23/74 20130101; B01D 3/16 20130101; C10G 65/00 20130101; C10M
2203/1006 20130101; C10M 2207/10 20130101; C10G 67/0454 20130101;
C10C 3/06 20130101; C10G 2300/10 20130101; C10G 2300/1077 20130101;
C08L 95/00 20130101; C10G 21/14 20130101; C10C 3/08 20130101; C10M
175/0033 20130101; C10N 2070/00 20130101; C10G 45/38 20130101; C10N
2040/25 20130101; C10N 2030/02 20130101; B01D 3/14 20130101; C10M
101/02 20130101; C10G 67/00 20130101; C10G 1/086 20130101; C10G
65/12 20130101; C10N 2020/02 20130101; C10G 2400/08 20130101; C10N
2020/017 20200501; C10N 2030/20 20130101; C10N 2020/011 20200501;
C10G 2300/1062 20130101; C10G 2400/10 20130101; C10M 2203/1065
20130101; B01D 3/10 20130101; C10M 2201/062 20130101; B01L 3/10
20130101; C10M 2201/06 20130101 |
International
Class: |
C10G 65/12 20060101
C10G065/12; C10G 65/00 20060101 C10G065/00; C10G 67/00 20060101
C10G067/00; B01D 3/10 20060101 B01D003/10; C10M 171/02 20060101
C10M171/02; C10M 175/00 20060101 C10M175/00; C10C 3/06 20060101
C10C003/06; C10G 67/04 20060101 C10G067/04; C10G 1/08 20060101
C10G001/08; C10G 45/38 20060101 C10G045/38; C10G 21/14 20060101
C10G021/14; B01D 3/14 20060101 B01D003/14; C10M 101/02 20060101
C10M101/02; B01J 23/74 20060101 B01J023/74; C10C 3/08 20060101
C10C003/08 |
Claims
1.-10. (canceled)
11. A method for making lubricant base stock, comprising:
performing solvent deasphalting using a C4+ solvent under effective
solvent deasphalting conditions on a feedstock having a T5 boiling
point of at least about 370.degree. C., the effective solvent
deasphalting conditions producing a yield of deasphalted oil of at
least about 50 wt % of the feedstock; hydroprocessing at least a
portion of the deasphalted oil under first effective
hydroprocessing conditions comprising first hydrocracking
conditions to form a hydroprocessed effluent, the at least a
portion of the deasphalted oil having an aromatics content of at
least about 50 wt %, the hydroprocessed effluent comprising a
sulfur content of 300 wppm or less, a nitrogen content of 100 wppm
or less, or a combination thereof; separating the hydroprocessed
effluent to form at least a fuels boiling range fraction, a first
fraction having a T.sub.5 distillation point of at least
370.degree. C., and a second fraction having a T.sub.5 distillation
point of at least 370.degree. C., the second fraction having a
higher kinematic viscosity at 100.degree. C. than the first
fraction; hydroprocessing at least a portion of the first fraction
under second effective hydroprocessing conditions, the second
effective hydroprocessing conditions comprising second aromatic
saturation conditions and second catalytic dewaxing conditions, to
form a first catalytically dewaxed effluent comprising a
370.degree. C.+ portion having a first kinematic viscosity at
100.degree. C., the at least a portion of the first fraction being
exposed to the second aromatic saturation conditions prior to the
second catalytic dewaxing conditions; and hydroprocessing at least
a portion of the second fraction under third effective
hydroprocessing conditions, the third effective hydroprocessing
conditions comprising third aromatic saturation conditions and
third catalytic dewaxing conditions, to form a second catalytically
dewaxed effluent comprising a 370.degree. C.+ portion having a
second kinematic viscosity at 100.degree. C. that is greater than
the first kinematic viscosity at 100.degree. C., the at least a
portion of the second fraction being exposed to the third aromatic
saturation conditions prior to the third catalytic dewaxing
conditions, wherein the second effective hydroprocessing conditions
are different from the third effective hydroprocessing
conditions.
12. The method of claim 11, wherein the second aromatic saturation
conditions comprise exposing the at least a portion of the first
fraction to an amorphous aromatic saturation catalyst.
13. The method of claim 11, wherein the first hydroprocessing
conditions further comprise first aromatic saturation conditions,
the first aromatic saturation conditions comprising exposing the at
least a portion of the deasphalted oil to a demetallization
catalyst, the at least a portion of the deasphalted oil being
exposed to the demetallization catalyst after exposing the at least
a portion of the deasphalted oil to the hydrocracking catalyst.
14. The method of claim 11, wherein the second effective
hydroprocessing conditions and third effective hydroprocessing
conditions are different based on a difference in at least one of a
hydrocracking pressure, a hydrocracking temperature, a dewaxing
pressure, and a dewaxing temperature.
15. The method of claim 11, further comprising recycling at least a
portion of the second catalytically dewaxed effluent as part of the
at least a portion of the deasphalted oil, as part of the at least
a portion of the first fraction, or a combination thereof
16. The method of claim 11, wherein the hydroprocessing at least a
portion of the first fraction and the hydroprocessing at least a
portion of the second fraction comprise block operation of a
processing system.
17. The method of claim 11, wherein separating the hydroprocessed
effluent further comprises forming an additional fraction having a
Ts distillation point of at least 370.degree. C., the method
further comprising: hydroprocessing at least a portion of the
additional fraction under third effective hydroprocessing
conditions, the third effective hydroprocessing conditions
comprising catalytic dewaxing conditions, to form a third
catalytically dewaxed effluent comprising a 370.degree. C.+ portion
having a kinematic viscosity at 100.degree. C. of 3.5 cSt or
more.
18. A method for making lubricant base stock, comprising:
performing solvent deasphalting using a C.sub.4+ solvent under
effective solvent deasphalting conditions on a feedstock having a
T5 boiling point of at least about 370.degree. C., the effective
solvent deasphalting conditions producing a yield of deasphalted
oil of at least about 50 wt % of the feedstock; hydroprocessing at
least a portion of the deasphalted oil under first effective
hydroprocessing conditions comprising first hydrocracking
conditions to form a hydroprocessed effluent, the at least a
portion of the deasphalted oil having an aromatics content of at
least about 50 wt %; separating the hydroprocessed effluent to form
at least a fuels boiling range fraction, a first fraction having a
Ts distillation point of at least 370.degree. C., and a second
fraction having a Ts distillation point of at least 370.degree. C.,
the second fraction having a higher kinematic viscosity at
100.degree. C. than the first fraction; hydroprocessing at least a
portion of the first fraction under second effective
hydroprocessing conditions, the second effective hydroprocessing
conditions comprising exposing the first fraction to a medium pore
dewaxing catalyst to form a first catalytically dewaxed effluent
comprising a 370.degree. C.+ portion having a first kinematic
viscosity at 100.degree. C.; and hydroprocessing at least a portion
of the second fraction under third effective hydroprocessing
conditions, the third effective hydroprocessing conditions
comprising exposing the second fraction to the medium pore dewaxing
catalyst to form a second catalytically dewaxed effluent comprising
a 370.degree. C.+ portion having a second kinematic viscosity at
100.degree. C. that is greater than the first kinematic viscosity
at 100.degree. C., wherein the second effective hydroprocessing
conditions are different from the third effective hydroprocessing
conditions.
19. The method of claim 18, wherein the medium pore dewaxing
catalyst comprises ZSM-5.
20. The method of claim 18, wherein the medium pore dewaxing
catalyst comprises 0.05 wt % or less of Group VIII metals.
21. The method of claim 18, wherein the at least a portion of the
deasphalted oil comprises a sulfur content of 300 wppm or more.
22. The method of claim 18, wherein at least a portion of the first
fraction, at least a portion of the second fraction, at least a
portion of the first catalytically dewaxed effluent, at least a
portion of the second catalytically dewaxed effluent, or a
combination thereof is used as a feed for a steam cracker.
23. The method of claim 18, wherein at least a portion of the
second catalytically dewaxed effluent is used as an asphalt blend
component.
24. The method of claim 18, wherein separating the hydroprocessed
effluent further comprises forming an additional fraction having a
T.sub.5 distillation point of at least 370.degree. C., the method
further comprising: hydroprocessing at least a portion of the
additional fraction under third effective hydroprocessing
conditions, the third effective hydroprocessing conditions
comprising catalytic dewaxing conditions, to form a third
catalytically dewaxed effluent comprising a 370.degree. C.+ portion
having a kinematic viscosity at 100.degree. C. of 3.5 cSt or more.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application Ser. No. 62/439,943 filed Dec. 29, 2016, which is
herein incorporated by reference in its entirety.
[0002] This application is related to three other co-pending U.S.
applications, filed on even date herewith, and identified by the
following Attorney Docket numbers and titles: 2016EM406-US2
entitled "Block Processing For Base Stock Production From
Deasphalted Oil"; 2017EM197 entitled "Block Processing With Bulk
Catalsyts For Base Stock Production From Deasphalted Oil" and
2017EM195 entitled "Base Stocks And Lubricant Compositions
Containing Same". Each of these co-pending U.S. applications is
hereby incorporated by reference herein in its entirety.
FIELD
[0003] Systems and methods are provided for production of lubricant
oil base stocks from deasphalted oils produced by low severity
deasphalting of resid fractions.
BACKGROUND
[0004] Lubricant base stocks are one of the higher value products
that can be generated from a crude oil or crude oil fraction. The
ability to generate lubricant base stocks of a desired quality is
often constrained by the availability of a suitable feedstock. For
example, most conventional processes for lubricant base stock
production involve starting with a crude fraction that has not been
previously processed under severe conditions, such as a virgin gas
oil fraction from a crude with moderate to low levels of initial
sulfur content.
[0005] In some situations, a deasphalted oil formed by propane
desaphalting of a vacuum resid can be used for additional lubricant
base stock production. Deasphalted oils can potentially be suitable
for production of heavier base stocks, such as bright stocks.
However, the severity of propane deasphalting required in order to
make a suitable feed for lubricant base stock production typically
results in a yield of only about 30 wt % deasphalted oil relative
to the vacuum resid feed.
[0006] U.S. Pat. No. 3,414,506 describes methods for making
lubricating oils by hydrotreating pentane-alcohol-deasphalted short
residue. The methods include performing deasphalting on a vacuum
resid fraction with a deasphalting solvent comprising a mixture of
an alkane, such as pentane, and one or more short chain alcohols,
such as methanol and isopropyl alcohol. The deasphalted oil is then
hydrotreated, followed by solvent extraction to perform sufficient
VI uplift to form lubricating oils.
[0007] U.S. Pat. No. 7,776,206 describes methods for catalytically
processing resids and/or deasphalted oils to form bright stock. A
resid-derived stream, such as a deasphalted oil, is hydroprocessed
to reduce the sulfur content to less than 1 wt % and reduce the
nitrogen content to less than 0.5 wt %. The hydroprocessed stream
is then fractionated to form a heavier fraction and a lighter
fraction at a cut point between 1150.degree. F.-1300.degree. F.
(620.degree. C.-705.degree. C.). The lighter fraction is then
catalytically processed in various manners to form a bright
stock.
SUMMARY
[0008] In various aspects, systems and methods are provided for
block operation during lubricant and/or fuels production from
deasphalted oil, such as deasphalted oil from a solvent
deasphalting process with a yield of deasphalted oil of at least 50
wt %. During "block" operation, a deaspahlted oil and/or the
hydroprocessed effluent from an initial processing stage can be
split into a plurality of fractions. The fractions can correspond,
for example, to feed fractions suitable for forming a light neutral
fraction, a heavy neutral fraction, and a bright stock fraction, or
the plurality of fractions can correspond to any other convenient
split into separate fractions. The plurality of separate fractions
can then be processed separately in the process train (or in the
sweet portion of the process train) for forming fuels and/or
lubricant base stocks. The separate processing can allow for
selection of conditions for forming lubricant fractions, such as
bright stock fractions, that have a cloud point that is lower than
the pour point.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 schematically shows an example of a configuration for
block catalytic processing of deasphalted oil to form lubricant
base stocks.
[0010] FIG. 2 schematically shows an example of a configuration for
block catalytic processing of deasphalted oil to form lubricant
base stocks.
[0011] FIG. 3 schematically shows an example of a configuration for
block catalytic processing of deasphalted oil to form lubricant
base stocks.
DETAILED DESCRIPTION
[0012] 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
[0013] In various aspects, methods are provided for producing Group
I and Group II lubricant base stocks, including Group I and Group
II bright stock, from deasphalted oils generated by low severity
C.sub.4+ deasphalting. Low severity deasphalting as used herein
refers to deasphalting under conditions that result in a high yield
of deasphalted oil (and/or a reduced amount of rejected asphalt or
rock), such as a deasphalted oil yield of at least 50 wt % relative
to the feed to deasphalting, or at least 55 wt %, or at least 60 wt
%, or at least 65 wt %, or at least 70 wt %, or at least 75 wt %.
The Group I base stocks (including bright stock) can be formed
without performing a solvent extraction on the deasphalted oil. The
Group II base stocks (including bright stock) can be formed using a
combination of catalytic and solvent processing. In contrast with
conventional bright stock produced from deasphalted oil formed at
low severity conditions, the Group I and Group II bright stock
described herein can be substantially free from haze after storage
for extended periods of time. This haze free Group II bright stock
can correspond to a bright stock with an unexpected
composition.
[0014] In various additional aspects, methods are provided for
catalytic processing of C.sub.4+ deasphalted oils to form Group II
bright stock. Forming Group II bright stock by catalytic processing
can provide a bright stock with unexpected compositional
properties. An example of such an unexpected property is a bright
stock with a cloud point that is lower than the pour point.
Conventionally, it is expected that the cloud point for a base
stock should correspond to a higher temperature than the pour
point. The cloud point can typically correspond to the temperature
related to the onset of crystallization. It has been unexpectedly
discovered that catalytically processed bright stock can have a
pour point that is based on the temperature at which the viscosity
of the fluid phase becomes too high for effective flow. While such
an increase in viscosity may or may not indicate a liquid-to-glass
phase transition, such a transition is not related to the onset of
crystallization that is usually associated with a cloud point. This
is in contrast to conventional base stocks, where the pour point
corresponds to a continuation of the crystallization and/or
liquid-to-solid phase transition. Such a base stock can have a
turbidity of 5 NTUs or less, or 3 NTUs or less, or 2 NTUs or
les.
[0015] Conventionally, crude oils are often described as being
composed of a variety of boiling ranges. Lower boiling range
compounds in a crude oil correspond to naphtha or kerosene fuels.
Intermediate boiling range distillate compounds can be used as
diesel fuel or as lubricant base stocks. If any higher boiling
range compounds are present in a crude oil, such compounds are
considered as residual or "resid" compounds, corresponding to the
portion of a crude oil that is left over after performing
atmospheric and/or vacuum distillation on the crude oil.
[0016] In some conventional processing schemes, a resid fraction
can be deasphalted, with the deasphalted oil used as part of a feed
for forming lubricant base stocks. In conventional processing
schemes a deasphalted oil used as feed for forming lubricant base
stocks is produced using propane deasphalting. This propane
deasphalting corresponds to a "high severity" deasphalting, as
indicated by a typical yield of deasphalted oil of about 40 wt % or
less, often 30 wt % or less, relative to the initial resid
fraction. In a typical lubricant base stock production process, the
deasphalted oil can then be solvent extracted to reduce the
aromatics content, followed by solvent dewaxing to form a base
stock. The low yield of deasphalted oil is based in part on the
inability of conventional methods to produce lubricant base stocks
from lower severity deasphalting that do not form haze over
time.
[0017] In some aspects, it has been discovered that using a mixture
of catalytic processing, such as hydrotreatment, and optionally
solvent processing (for the bright stock), such as solvent
dewaxing, can be used to produce lubricant base stocks from
deasphalted oil while also producing base stocks that have little
or no tendency to form haze over extended periods of time. The
deasphalted oil can be produced by deasphalting process that uses a
C.sub.4 solvent, a C.sub.5 solvent, a C.sub.6+ solvent, a mixture
of two or more C.sub.4+ solvents, or a mixture of two or more
C.sub.5+ solvents. The deasphalting process can further correspond
to a process with a yield of deasphalted oil of at least 50 wt %
for a vacuum resid feed having a T10 distillation point (or
optionally a T5 distillation point) of at least 510.degree. C., or
a yield of at least 60 wt %, or at least 65 wt %, or at least 70 wt
%. It is believed that the reduced haze formation is due in part to
the reduced or minimized differential between the pour point and
the cloud point for the base stocks and/or due in part to forming a
bright stock with a cloud point of -5.degree. C. or less. The light
neutral and heavy neutral base stocks can avoid haze formation
without the need for additional solvent processing.
[0018] For production of Group I base stocks, a deasphalted oil can
be hydroprocessed (hydrotreated and/or hydrocracked) under
conditions sufficient to achieve a desired viscosity index increase
for resulting base stock products. The hydroprocessed effluent can
be fractionated to separate lower boiling portions from a lubricant
base stock boiling range portion. The lubricant base stock boiling
range portion can then be solvent dewaxed to produce a dewaxed
effluent. The dewaxed effluent can be separated to form a plurality
of base stocks with a reduced tendency (such as no tendency) to
form haze over time.
[0019] For production of Group II base stocks, in some aspects a
deasphalted oil can be hydroprocessed (hydrotreated and/or
hydrocracked), so that .about.700.degree. F.+ (370.degree. C.+)
conversion is 10 wt % to 40 wt %. The hydroprocessed effluent can
be fractionated to separate lower boiling portions from a lubricant
base stock boiling range portion. The lubricant boiling range
portion can then be hydrocracked, dewaxed, and hydrofinished to
produce a catalytically dewaxed effluent. Optionally but
preferably, the lubricant boiling range portion can be
underdewaxed, so that the wax content of the catalytically dewaxed
heavier portion or potential bright stock portion of the effluent
is at least 6 wt %, or at least 8 wt %, or at least 10 wt %. This
underdewaxing can also be suitable for forming light or medium or
heavy neutral lubricant base stocks that do not require further
solvent upgrading to form haze free base stocks. In this
discussion, the heavier portion/potential bright stock portion can
roughly correspond to a 538.degree. C.+ portion of the dewaxed
effluent. The catalytically dewaxed heavier portion of the effluent
can then be solvent dewaxed to form a solvent dewaxed effluent. The
solvent dewaxed effluent can be separated to form a plurality of
base stocks with a reduced tendency (such as no tendency) to form
haze over time, including at least a portion of a Group II bright
stock product.
[0020] For production of Group II base stocks, in other aspects a
deasphalted oil can be hydroprocessed (hydrotreated and/or
hydrocracked), so that 370.degree. C.+ conversion is at least 40 wt
%, or at least 50 wt %. The hydroprocessed effluent can be
fractionated to separate lower boiling portions from a lubricant
base stock boiling range portion. The lubricant base stock boiling
range portion can then be hydrocracked, dewaxed, and hydrofinished
to produce a catalytically dewaxed effluent. At least a heavier
portion of the catalytically dewaxed effluent can then be solvent
extracted to form a raffinate. The raffinate can be separated to
form base stocks with a reduced tendency (such as no tendency) to
form haze over time, including at least a portion of a Group II
bright stock product. The lighter portions of the catalytically
dewaxed effluent can be used to form light neutral and heavy
neutral base stocks without requiring further solvent processing to
form a clear and bright (haze-free) product.
[0021] In some aspects, it has been discovered that catalytic
processing can be used to produce Group II bright stock with
unexpected compositional properties from C.sub.3, C.sub.4, C.sub.5,
and/or C.sub.5+ deasphalted oil. The deasphalted oil can be
hydrotreated to reduce the content of heteroatoms (such as sulfur
and nitrogen), followed by catalytic dewaxing under sweet
conditions. Optionally, hydrocracking can be included as part of
the sour hydrotreatment stage and/or as part of the sweet dewaxing
stage.
[0022] Optionally, the systems and methods described herein can be
used in "block" operation to allow for additional improvements in
yield and/or product quality. During "block" operation, a
deaspahlted oil and/or the hydroprocessed effluent from the sour
processing stage can be split into a plurality of fractions. The
fractions can correspond, for example, to feed fractions suitable
for forming a light neutral fraction, a heavy neutral fraction, and
a bright stock fraction, or the plurality of fractions can
correspond to any other convenient split into separate fractions.
The plurality of separate fractions can then be processed
separately in the process train (or in the sweet portion of the
process train) for forming lubricant base stocks. For example, the
light neutral portion of the feed can be processed for a period of
time, followed by processing of the heavy neutral portion, followed
by processing of a bright stock portion. During the time period
when one type of fraction is being processed, storage tanks can be
used to hold the remaining fractions.
[0023] Block operation can allow the processing conditions in the
process train to be tailored to each type of lubricant fraction.
For example, the amount of sweet processing stage conversion of the
heavy neutral fraction can be lower than the amount of sweet
processing stage conversion for the light neutral fraction. This
can reflect the fact that heavy neutral lubricant base stocks may
not need as high a viscosity index as light neutral base
stocks.
[0024] Another option for modifying the production of base stocks
can be to recycle a portion of at least one lubricant base stock
product for further processing in the process train. This can
correspond to recycling a portion of a base stock product for
further processing in the sour stage and/or recycling a portion of
a base stock product for further processing in the corresponding
sweet stage. Optionally, a base stock product can be recycled for
further processing in a different phase of block operation, such as
recycling light neutral base stock product formed during block
processing of the heavy neutral fraction for further processing
during block processing of the light neutral fraction. The amount
of base stock product recycled can correspond to any convenient
amount of a base stock product effluent from the fractionator, such
as 1 wt % to 50 wt % of a base stock product effluent, or 1 wt % to
20 wt %.
[0025] Recycling a portion of a base stock product effluent can
optionally be used while operating a lube processing system at
higher than typical levels of fuels conversion. When using a
conventional feed for lubricant production, conversion of feed
relative to 370.degree. C. can be limited to 65 wt % or less.
Conversion of more than 65 wt % of a feed relative to 370.degree.
C. is typically not favored due to loss of viscosity index with
additional conversion. At elevated levels of conversion, the loss
of VI with additional conversion is believed to be due to cracking
and/or conversion of isoparaffins within a feed. For feeds derived
from deasphalted oil, however, the amount of isoparaffins within a
feed is lower than a conventional feed. As a result, additional
conversion can be performed without loss of VI. In some aspects,
converting at least 70 wt % of a feed, or at least 75 wt %, or at
least 80 wt % can allow for production of lubricant base stocks
with substantially improved cold flow properties while still
maintaining the viscosity index of the products at a similar value
to the viscosity index at a conventional conversion of 60 wt %.
[0026] Group I base stocks or base oils are defined as base stocks
with less than 90 wt % saturated molecules and/or at least 0.03 wt
% sulfur content. Group I base stocks also have a viscosity index
(VI) of at least 80 but less than 120. Group II base stocks or base
oils contain at least 90 wt % saturated molecules and less than
0.03 wt % sulfur. Group II base stocks also have a viscosity index
of at least 80 but less than 120. Group III base stocks 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.
[0027] In some aspects, a Group III base stock as described herein
may correspond to a Group III+ base stock. Although a generally
accepted definition is not available, a Group III+ base stock can
generally correspond to a base stock that satisfies the
requirements for a Group III base stock while also having at least
one property that is enhanced relative to a Group III
specification. The enhanced property can correspond to, for
example, having a viscosity index that is substantially greater
than the required specification of 120, such as a Group III base
stock having a VI of at least 130, or at least 135, or at least
140. Similarly, in some aspects, a Group II base stock as described
herein may correspond to a Group II+ base stock. Although a
generally accepted definition is not available, a Group II+ base
stock can generally correspond to a base stock that satisfies the
requirements for a Group II base stock while also having at least
one property that is enhanced relative to a Group II specification.
The enhanced property can correspond to, for example, having a
viscosity index that is substantially greater than the required
specification of 80, such as a Group II base stock having a VI of
at least 103, or at least 108, or at least 113.
[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 this discussion, conditions may be provided for various
types of hydroprocessing of feeds or effluents. Examples of
hydroprocessing can include, but are not limited to, one or more of
hydrotreating, hydrocracking, catalytic dewaxing, and
hydrofinishingaromatic saturation. Such hydroprocessing conditions
can be controlled to have desired values for the conditions (e.g.,
temperature, pressure, LHSV, treat gas rate) by using at least one
controller, such as a plurality of controllers, to control one or
more of the hydroprocessing conditions. In some aspects, for a
given type of hydroprocessing, at least one controller can be
associated with each type of hydroprocessing condition. In some
aspects, one or more of the hydroprocessing conditions can be
controlled by an associated controller. Examples of structures that
can be controlled by a controller can include, but are not limited
to, valves that control a flow rate, a pressure, or a combination
thereof; heat exchangers and/or heaters that control a temperature;
and one or more flow meters and one or more associated valves that
control relative flow rates of at least two flows. Such controllers
can optionally include a controller feedback loop including at
least a processor, a detector for detecting a value of a control
variable (e.g., temperature, pressure, flow rate, and a processor
output for controlling the value of a manipulated variable (e.g.,
changing the position of a valve, increasing or decreasing the duty
cycle and/or temperature for a heater). Optionally, at least one
hydroprocessing condition for a given type of hydroprocessing may
not have an associated controller.
[0030] In this discussion, unless otherwise specified a lubricant
boiling range fraction corresponds to a fraction having an initial
boiling point or alternatively a T5 boiling point of at least about
370.degree. C. (.about.700.degree. F.). A distillate fuel boiling
range fraction, such as a diesel product fraction, corresponds to a
fraction having a boiling range from about 193.degree. C.
(375.degree. F.) to about 370.degree. C. (.about.700.degree. F.).
Thus, distillate fuel boiling range fractions (such as distillate
fuel product fractions) can have initial boiling points (or
alternatively T5 boiling points) of at least about 193.degree. C.
and final boiling points (or alternatively T95 boiling points) of
about 370.degree. C. or less. A naphtha boiling range fraction
corresponds to a fraction having a boiling range from about
36.degree. C. (122.degree. F.) to about 193.degree. C. (375.degree.
F.) to about 370.degree. C. (.about.700.degree. F.). Thus, naphtha
fuel product fractions can have initial boiling points (or
alternatively T5 boiling points) of at least about 36.degree. C.
and final boiling points (or alternatively T95 boiling points) of
about 193.degree. C. or less. It is noted that 36.degree. C.
roughly corresponds to a boiling point for the various isomers of a
C5 alkane. A fuels boiling range fraction can correspond to a
distillate fuel boiling range fraction, a naphtha boiling range
fraction, or a fraction that includes both distillate fuel boiling
range and naphtha boiling range components. Light ends are defined
as products with boiling points below about 36.degree. C., which
include various C1-C4 compounds. When determining a boiling point
or a boiling range for a feed or product fraction, an appropriate
ASTM test method can be used, such as the procedures described in
ASTM D2887, D2892, and/or D86. Preferably, ASTM D2887 should be
used unless a sample is not appropriate for characterization based
on ASTM D2887. For example, for samples that will not completely
elute from a chromatographic column, ASTM D7169 can be used.
Process Variations
[0031] In various aspects, fixed bed (such as trickle-bed)
hydroprocessing systems can be used to perform the various types of
hydroprocessing described herein, including demetallization,
hydrotreating, hydrocracking, catalytic dewaxing, and/or aromatic
saturation. Additionally or alternately, in some aspects, it can be
beneficial to perform at least a portion of the sour stage
processing in a reactor having a configuration different from a
trickle-bed reactor, such as an ebullated bed reactor or a slurry
reactor. These alternative configurations can be beneficial, for
example, for processing deasphalted oils that may have less
desirable properties. For example, some deasphalted oils may have
elevated levels of metals and/or micro carbon residue. Use of an
alternative reactor configuration in the sour stage can be
beneficial for allowing catalyst removal and/or regeneration
without stopping operation of the total reaction system.
Additionally, the alternative reactor configurations could be
beneficial for deasphalted oils that have a Bureau of Mines
Correlation Index (BMCI) minus the toluene equivalence (TE) of less
than 50 (e.g. BMCI-TE<50). This can happen with low solvency
crudes, or if asphaltene entrainment is occurring in the
deasphalter. In such an aspect, the alternative reactor
configurations can avoid compatibility issues, such as plugging,
that could occur in a fixed bed reactor configuration.
[0032] One example of a suitable alternative configuration can be
to use an ebullated bed reactor to perform at least a portion of
the hydroprocessing in the sour stage. For example, one or more
ebullated bed reactors can be used to achieve between 30 wt % to 85
wt %% conversion of a deasphalted oil relative to 650.degree. F.
(343.degree. C.). The converted fraction can then be separated out,
followed by further processing of the 343.degree. C.+ fraction, in
a fixed bed reactor including hydrotreating and/or hydrocracking
catalyst to achieve a sulfur level of 50 wppm or less and a
nitrogen level of 20 wppm or less. This product from the fixed bed
reactor, after optional separation to remove fuels boiling range
(and lower) components, can then be processed in a sweet processing
stage as described herein to form lubricant base stocks (optionally
including bright stocks).
[0033] Another example of a suitable alternative configuration can
be to use a slurry hydroprocessing reactor to perform at least a
portion of the hydroprocessing in the sour stage. For example, one
or more slurry hydroprocessing reactors can be used to achieve
between 50 wt % to 95 wt %% conversion of a deasphalted oil
relative to 650.degree. F. (343.degree. C.). The converted fraction
can then be separated out, followed by further processing of the
343.degree. C.+ fraction, in a fixed bed reactor including
hydrotreating and/or hydrocracking catalyst to achieve a sulfur
level of 50 wppm or less and a nitrogen level of 20 wppm or less.
This product from the fixed bed reactor, after optional separation
to remove fuels boiling range (and lower) components, can then be
processed in a sweet processing stage as described herein to form
lubricant base stocks (optionally including bright stocks).
[0034] Still another option for handling deasphalted oils with
elevated contents of metals and/or micro carbon residue can be to
perform solvent extraction prior to hydroprocessing in the sour
stage, such as solvent extraction using N-methylpyrrolidone. This
can in some ways correspond to a second "deasphalting" process, but
the extract from the solvent extraction process can have lower
contaminant levels than a typical deasphalter rock fraction.
Additionally, the extract can have a substantially lower viscosity
than a typical deasphalter rock fraction. This can allow the
extract to be incorporated into a variety of products or feeds with
a reduced or minimized amount of fouling or other difficulties,
such as incorporation into asphalt products, feed for fluid
catalytic cracking, or feed for coking.
[0035] In various aspects, the sweet stage of a reaction system for
production of base stocks in block operation can include an
optional aromatic saturation catalyst, a hydrocracking catalyst, a
dewaxing catalyst, and a second aromatic saturation catalyst. In
aspects where the initial optional aromatic saturation catalyst is
present, the second aromatic saturation catalyst can be the same or
different from the optional aromatic saturation catalyst. This
combination of catalysts can allow for additional conversion of the
effluent from the sour stage, dewaxing to improve cold flow
properties, and additional aromatic saturation to provide base
stocks with 95 wt % or more of saturates. In some aspects, it can
be beneficial to use an alternative configuration in the sweet
stage.
[0036] As an example, after conversion of the deasphalted oil in
the sour stage, either after separation to remove a 650.degree. F.-
(343.degree. C.-) portion of the sour stage effluent or after
separation of the 343.degree. C.+ portion sour stage effluent into
separate streams for block processing, at least a portion of the
sour stage effluent can be solvent dewaxed to remove the wax. This
type of configuration can potentially reduce or minimize the cloud
pointpour point spread for the resulting base stocks, which for
paraffinic crudes may provide better low or no haze performance of
the bright stock.
[0037] As another example, after conversion of the deasphalted oil
in the sour stage, either after separation to remove a 650.degree.
F.- (343.degree. C.-) portion of the sour stage effluent or after
separation of the 343.degree. C.+ portion sour stage effluent into
separate streams for block processing, at least a portion of the
sour stage effluent can be processed by exposing the sour stage
effluent to a fixed bed of ZSM-5 or another medium pore zeolitic
dewaxing catalyst that performs dewaxing primarily by cracking.
Optionally, the medium pore dewaxing catalyst can include supported
noble metal(s) and/or supported base metal(s). Alternatively, the
medium pore dewaxing catalyst can be substantially free of
supported catalytic metals. Exposing the sour stage effluent to a
medium pore dewaxing catalyst can result in lower lubricant
viscosity index, but such a dewaxing catalyst can be more tolerant
of sulfur and nitrogen slip in the hydroprocessed deasphalted oil
from the sour stage, such as in aspects where the dewaxing catalyst
does not include supported metals. This could allow, for example,
the sour stage to be operated at a lower severity, with the benefit
of greater total lube yields, and a high viscosity for the bright
stock.
[0038] In various aspects, hydroprocessing of deasphalted oil to
form lubricant base stocks can result in formation of a variety of
products. In addition to light neutral, heavy neutral, and bright
stock products formed by block processing, additional fuels and
lubricant products can be formed. The fuels products can include
naphtha and diesel fractions formed due to conversion in the sour
stage and conversion in the sweet stage. The sour stage fuels
products can optionally be processed further, if necessary, in
order to satisfy desired standards for sulfur and nitrogen content.
The additional lubricant products can include additional light
neutral and heavy neutral products that are formed during block
processing. For example, sweet stage processing of the heavy
neutral block feed can result in some "conversion" of heavy neutral
base stock to light neutral base stock. Similarly, sweet stage
processing of the bright stock block feed can result in some
"conversion" of bright stock to light neutral base stock and/or
heavy neutral base stock.
[0039] In some aspects, alternative types of products and/or
product dispositions can be generated in conjunction with
hydroprocessing of a deasphalted oil. For example, various sour
stage and/or sweet stage effluents can be suitable for use as a
steam cracker feed. Both the sour stage hydrocrackate and the
basestock products, particularly the heavy diesel and naphtha,
and/or any narrow boiling range fractions that may be distilled in
between lube cuts to manage lube properties, can make suitable
steam cracker feeds. It could be a single component, a blend of a
few components, or the entire sour stage product which may be sent
to a steam cracker. Such a steam cracker feed can have 98 wt % or
more saturates for the sweet products and 75 wt % or more saturates
for the hydrocrackates, which can be beneficial in a steam cracker
feed. Additionally, such a feed can be low in sulfur which can
reduce or minimize tar formation.
[0040] As another example, the bright stock product can be used as
an unexpectedly beneficial fluxant for asphalt production. The
bright stock is sufficiently heavy to avoid mass loss, has low
viscosity, and although the saturates content is relatively high,
because it is dewaxed it has very low wax. Wax is a detrimental
quality for asphalt, and most low viscosity fluxes for asphalt type
streams that are also non-toxic, like vacuum gas oils, have
significant quantities of wax. This can make a bright stock made
according to the processes described herein a suitable flux for a
high asphaltene, high viscosity asphalt blend component, such as
deasphalter rock, or deasphalter rock from a high-lift
deasphalter.
[0041] In various aspects, the sweet stage of the reaction system
can include a hydrocracking catalyst followed (downstream) by a
dewaxing catalyst followed by an aromatic saturation catalyst. For
example, the sweet stage of a reaction system can include a first
reactor containing hydrocracking catalyst, a second reactor
containing dewaxing catalyst, and a third reactor containing
aromatic saturation catalyst. In some aspects, other types of
catalyst configurations in the sweet stage can be beneficial.
[0042] As an example, the first reactor in the sweet stage can
include a hydrocracking catalyst followed by an aromatic saturation
catalyst. Including both hydrocracking and aromatic saturation
functionality in the initial part of the sweet stage can be
beneficial for allowing boiling point conversion and/or viscosity
index upgrading that can be tailored for each type of blocked feed.
Because this reactor is a sweet processing stage, the temperature
can be relatively low, thus allowing effective aromatic saturation
(reduced amount of constraint due to equilibrium) while still being
able to achieve desired boiling point conversion and/or viscosity
index upgrading.
[0043] As another example, the initial reactor or portion of the
sweet stage can include an aromatic saturation catalyst without the
presence of a hydrocracking catalyst. This type of configuration
can provide superior yield for basestocks that do not require
additional viscosity index upgrade in the sweet stage. Additionally
or alternately, at end of run, the lack of a hydrocracking catalyst
can allow the sweet stage reactors (or at least the initial
reactor) to be operated to be operated at higher temperature to
achieve desired aromatic saturation without excessive cracking.
[0044] In various aspects, the sour stage of the reaction system
can include one or more optional demetallization catalysts followed
(downstream) by a hydrotreating catalyst followed by a
hydrocracking catalyst. In some aspects, a large pore catalyst,
such as a demetallization catalyst, can be included downstream from
the hydrocracking catalyst. Such a large pore catalyst downstream
from the hydrocracking catalyst can be beneficial due to the
differences between a feed corresponding to a high yield
deasphalted oil and a conventional feed for lubricant production.
During processing of a conventional feed for lubricant production,
removal of mercaptans can potentially pose a challenge at the end
of a sour stage. A conventional hydrotreating catalyst after a
hydrocracking catalyst can be suitable for removal of such
mercaptans. For a feed based on a deasphalted oil, the
substantially higher percentage of multi-ring structures in the
feed can result in formation of polynuclear aromatics during
hydrocracking. Such polynuclear aromatics are not as readily
treated using a conventional hydrotreating catalyst. However, the
larger pore size of a demetallization catalyst (such as 200 nm or
greater median pore size) can be allow demetallization catalysts to
be effective for saturation of polynuclear aromatics. Such
demetallization catalsyts can also be effective for mercaptan
removal.
Feedstocks
[0045] In various aspects, at least a portion of a feedstock for
processing as described herein can correspond to a vacuum resid
fraction or another type 950.degree. F.+ (510.degree. C.+) or
1000.degree. F.+ (538.degree. C.+) fraction. Another example of a
method for forming a 950.degree. F.+ (510.degree. C.+) or
1000.degree. F.+ (538.degree. C.+) fraction is to perform a high
temperature flash separation. The 950.degree. F.+ (510.degree. C.+)
or 1000.degree. F.+ (538.degree. C.+) fraction formed from the high
temperature flash can be processed in a manner similar to a vacuum
resid.
[0046] A vacuum resid fraction or a 950.degree. F.+ (510.degree.
C.+) fraction formed by another process (such as a flash
fractionation bottoms or a bitumen fraction) can be deasphalted at
low severity to form a deasphalted oil. Optionally, the feedstock
can also include a portion of a conventional feed for lubricant
base stock production, such as a vacuum gas oil.
[0047] A vacuum resid (or other 510.degree. C.+) fraction can
correspond to a fraction with a T5 distillation point (ASTM D2892,
or ASTM D7169 if the fraction will not completely elute from a
chromatographic system) of at least about 900.degree. F.
(482.degree. C.), or at least 950.degree. F. (510.degree. C.), or
at least 1000.degree. F. (538.degree. C.). Alternatively, a vacuum
resid fraction can be characterized based on a T10 distillation
point (ASTM D2892D7169) of at least about 900.degree. F.
(482.degree. C.), or at least 950.degree. F. (510.degree. C.), or
at least 1000.degree. F. (538.degree. C.).
[0048] Resid (or other 510.degree. C.+) fractions can be high in
metals. For example, a resid fraction can be high in total nickel,
vanadium and iron contents. In an aspect, a resid fraction can
contain at least 0.00005 grams of Ni/V/Fe (50 wppm) or at least
0.0002 grams of Ni/V/Fe (200 wppm) per gram of resid, on a total
elemental basis of nickel, vanadium and iron. In other aspects, the
heavy oil can contain at least 500 wppm of nickel, vanadium, and
iron, such as up to 1000 wppm or more.
[0049] Contaminants such as nitrogen and sulfur are typically found
in resid (or other 510.degree. C.+) fractions, often in
organically-bound form. Nitrogen content can range from about 50
wppm to about 10,000 wppm elemental nitrogen or more, based on
total weight of the resid fraction. Sulfur content can range from
500 wppm to 100,000 wppm elemental sulfur or more, based on total
weight of the resid fraction, or from 1000 wppm to 50,000 wppm, or
from 1000 wppm to 30,000 wppm.
[0050] Still another method for characterizing a resid (or other
510.degree. C.+) fraction is based on the Conradson carbon residue
(CCR) of the feedstock. The Conradson carbon residue of a resid
fraction can be at least about 5 wt %, such as at least about 10 wt
% or at least about 20 wt %. Additionally or alternately, the
Conradson carbon residue of a resid fraction can be about 50 wt %
or less, such as about 40 wt % or less or about 30 wt % or
less.
[0051] In some aspects, a vacuum gas oil fraction can be
co-processed with a deasphalted oil. The vacuum gas oil can be
combined with the deasphalted oil in various amounts ranging from
20 parts (by weight) deasphalted oil to 1 part vacuum gas oil
(i.e., 20:1) to 1 part deasphalted oil to 1 part vacuum gas oil. In
some aspects, the ratio of deasphalted oil to vacuum gas oil can be
at least 1:1 by weight, or at least 1.5:1, or at least 2:1. Typical
(vacuum) gas oil fractions can include, for example, fractions with
a T5 distillation point to T95 distillation point of 650.degree. F.
(343.degree. C.)-1050.degree. F. (566.degree. C.) or 650.degree. F.
(343.degree. C.)-1000.degree. F. (538.degree. C.) or 650.degree. F.
(343.degree. C.)-950.degree. F. (510.degree. C.), or 650.degree. F.
(343.degree. C.)-900.degree. F. (482.degree. C.), or
.about.700.degree. F. (370.degree. C.).about.1050.degree. F.
(566.degree. C.), or .about.700.degree. F. (370.degree.
C.)-1000.degree. F. (538.degree. C.) or .about.700.degree. F.
(370.degree. C.)-950.degree. F. (510.degree. C.) or
.about.700.degree. F. (370.degree. C.)-900.degree. F. (482.degree.
C.), or 750.degree. F. (399.degree. C.)-1050.degree. F.
(566.degree. C.), or 750.degree. F. (399.degree. C.)-1000.degree.
F. (538.degree. C.), or 750.degree. F. (399.degree. C.)-950.degree.
F. (510.degree. C.), or 750.degree. F. (399.degree. C.)-900.degree.
F. (482.degree. C.). For example a suitable vacuum gas oil fraction
can have a T5 distillation point of at least 343.degree. C. and a
T95 distillation point of 566.degree. C. or less; or a T10
distillation point of at least 343.degree. C. and a T90
distillation point of 566.degree. C. or less; or a T5 distillation
point of at least 370.degree. C. and a T95 distillation point of
566.degree. C. or less; or a T5 distillation point of at least
343.degree. C. and a T95 distillation point of 538.degree. C. or
less.
Solvent Deasphalting
[0052] Solvent deasphalting is a solvent extraction process. In
some aspects, suitable solvents for methods as described herein
include alkanes or other hydrocarbons (such as alkenes) containing
4 to 7 carbons per molecule. Examples of suitable solvents include
n-butane, isobutane, n-pentane, C.sub.4+ alkanes, C.sub.5+ alkanes,
C.sub.4+ hydrocarbons, and C.sub.5+ hydrocarbons. In other aspects,
suitable solvents can include C.sub.3 hydrocarbons, such as
propane. In such other aspects, examples of suitable solvents
include propane, n-butane, isobutane, n-pentane, C.sub.3+ alkanes,
C.sub.4+ alkanes, C.sub.5+ alkanes, C.sub.3+ hydrocarbons, C.sub.4+
hydrocarbons, and C.sub.5+ hydrocarbons
[0053] In this discussion, a solvent comprising Cn (hydrocarbons)
is defined as a solvent composed of at least 80 wt % of alkanes
(hydrocarbons) having n carbon atoms, or at least 85 wt %, or at
least 90 wt %, or at least 95 wt %, or at least 98 wt %. Similarly,
a solvent comprising C.sub.n+ (hydrocarbons) is defined as a
solvent composed of at least 80 wt % of alkanes (hydrocarbons)
having n or more carbon atoms, or at least 85 wt %, or at least 90
wt %, or at least 95 wt %, or at least 98 wt %.
[0054] In this discussion, a solvent comprising C.sub.n alkanes
(hydrocarbons) is defined to include the situation where the
solvent corresponds to a single alkane (hydrocarbon) containing n
carbon atoms (for example, n=3, 4, 5, 6, 7) as well as the
situations where the solvent is composed of a mixture of alkanes
(hydrocarbons) containing n carbon atoms. Similarly, a solvent
comprising C.sub.n+ alkanes (hydrocarbons) is defined to include
the situation where the solvent corresponds to a single alkane
(hydrocarbon) containing n or more carbon atoms (for example, n=3,
4, 5, 6, 7) as well as the situations where the solvent corresponds
to a mixture of alkanes (hydrocarbons) containing n or more carbon
atoms. Thus, a solvent comprising C.sub.4+ alkanes can correspond
to a solvent including n-butane; a solvent include n-butane and
isobutane; a solvent corresponding to a mixture of one or more
butane isomers and one or more pentane isomers; or any other
convenient combination of alkanes containing 4 or more carbon
atoms. Similarly, a solvent comprising C.sub.5+ alkanes
(hydrocarbons) is defined to include a solvent corresponding to a
single alkane (hydrocarbon) or a solvent corresponding to a mixture
of alkanes (hydrocarbons) that contain 5 or more carbon atoms.
Alternatively, other types of solvents may also be suitable, such
as supercritical fluids. In various aspects, the solvent for
solvent deasphalting can consist essentially of hydrocarbons, so
that at least 98 wt % or at least 99 wt % of the solvent
corresponds to compounds containing only carbon and hydrogen. In
aspects where the deasphalting solvent corresponds to a C.sub.4+
deasphalting solvent, the C.sub.4+ deasphalting solvent can include
less than 15 wt % propane and/or other C.sub.3 hydrocarbons, or
less than 10 wt %, or less than 5 wt %, or the C.sub.4+
deasphalting solvent can be substantially free of propane and/or
other C.sub.3 hydrocarbons (less than 1 wt %). In aspects where the
deasphalting solvent corresponds to a C.sub.5+ deasphalting
solvent, the C.sub.5+ deasphalting solvent can include less than 15
wt % propane, butane and/or other C.sub.3-C.sub.4 hydrocarbons, or
less than 10 wt %, or less than 5 wt %, or the C.sub.5+
deasphalting solvent can be substantially free of propane, butane,
and/or other C.sub.3-C.sub.4 hydrocarbons (less than 1 wt %). In
aspects where the deasphalting solvent corresponds to a C.sub.3+
deasphalting solvent, the C.sub.3+ deasphalting solvent can include
less than 10 wt % ethane and/or other C.sub.2 hydrocarbons, or less
than 5 wt %, or the C.sub.3+ deasphalting solvent can be
substantially free of ethane and/or other C.sub.2 hydrocarbons
(less than 1 wt %).
[0055] Deasphalting of heavy hydrocarbons, such as vacuum resids,
is known in the art and practiced commercially. A deasphalting
process typically corresponds to contacting a heavy hydrocarbon
with an alkane solvent (propane, butane, pentane, hexane, heptane
etc and their isomers), either in pure form or as mixtures, to
produce two types of product streams. One type of product stream
can be a deasphalted oil extracted by the alkane, which is further
separated to produce deasphalted oil stream. A second type of
product stream can be a residual portion of the feed not soluble in
the solvent, often referred to as rock or asphaltene fraction. The
deasphalted oil fraction can be further processed into make fuels
or lubricants. The rock fraction can be further used as blend
component to produce asphalt, fuel oil, and/or other products. The
rock fraction can also be used as feed to gasification processes
such as partial oxidation, fluid bed combustion or coking
processes. The rock can be delivered to these processes as a liquid
(with or without additional components) or solid (either as pellets
or lumps).
[0056] During solvent deasphalting, a resid boiling range feed
(optionally also including a portion of a vacuum gas oil feed) can
be mixed with a solvent. Portions of the feed that are soluble in
the solvent are then extracted, leaving behind a residue with
little or no solubility in the solvent. The portion of the
deasphalted feedstock that is extracted with the solvent is often
referred to as deasphalted oil. Typical solvent deasphalting
conditions include mixing a feedstock fraction with a solvent in a
weight ratio of from about 1:2 to about 1:10, such as about 1:8 or
less. Typical solvent deasphalting temperatures range from
40.degree. C. to 200.degree. C., or 40.degree. C. to 150.degree.
C., depending on the nature of the feed and the solvent. The
pressure during solvent deasphalting can be from about 50 psig (345
kPag) to about 500 psig (3447 kPag).
[0057] It is noted that the above solvent deasphalting conditions
represent a general range, and the conditions will vary depending
on the feed. For example, under typical deasphalting conditions,
increasing the temperature can tend to reduce the yield while
increasing the quality of the resulting deasphalted oil. Under
typical deasphalting conditions, increasing the molecular weight of
the solvent can tend to increase the yield while reducing the
quality of the resulting deasphalted oil, as additional compounds
within a resid fraction may be soluble in a solvent composed of
higher molecular weight hydrocarbons. Under typical deasphalting
conditions, increasing the amount of solvent can tend to increase
the yield of the resulting deasphalted oil. As understood by those
of skill in the art, the conditions for a particular feed can be
selected based on the resulting yield of deasphalted oil from
solvent deasphalting. In aspects where a C.sub.3 deasphalting
solvent is used, the yield from solvent deasphalting can be 40 wt %
or less. In some aspects, C.sub.4 deasphalting can be performed
with a yield of deasphalted oil of 50 wt % or less, or 40 wt % or
less. In various aspects, the yield of deasphalted oil from solvent
deasphalting with a C.sub.4+ solvent can be at least 50 wt %
relative to the weight of the feed to deasphalting, or at least 55
wt %, or at least 60 wt % or at least 65 wt %, or at least 70 wt %.
In aspects where the feed to deasphalting includes a vacuum gas oil
portion, the yield from solvent deasphalting can be characterized
based on a yield by weight of a 950.degree. F.+ (510.degree. C.)
portion of the deasphalted oil relative to the weight of a
510.degree. C.+portion of the feed. In such aspects where a
C.sub.4+ solvent is used, the yield of 510.degree. C.+ deasphalted
oil from solvent deasphalting can be at least 40 wt % relative to
the weight of the 510.degree. C.+ portion of the feed to
deasphalting, or at least 50 wt %, or at least 55 wt %, or at least
60 wt % or at least 65 wt %, or at least 70 wt %. In such aspects
where a C.sub.4- solvent is used, the yield of 510.degree. C.+
deasphalted oil from solvent deasphalting can be 50 wt % or less
relative to the weight of the 510.degree. C.+ portion of the feed
to deasphalting, or 40 wt % or less, or 35 wt % or less.
Hydrotreating and Hydrocracking
[0058] After deasphalting, the deasphalted oil (and any additional
fractions combined with the deasphalted oil) can undergo further
processing to form lubricant base stocks. This can include
hydrotreatment and/or hydrocracking to remove heteroatoms to
desired levels, reduce Conradson Carbon content, and/or provide
viscosity index (VI) uplift. Depending on the aspect, a deasphalted
oil can be hydroprocessed by hydrotreating, hydrocracking, or
hydrotreating and hydrocracking. Optionally, one or more catalyst
beds and/or stages of demetallization catalyst can be included
prior to the initial bed of hydrotreating and/or hydrocracking
catalyst. Optionally, the hydroprocessing can further include
exposing the deasphalted oil to a base metal aromatic saturation
catalyst. It is noted that a base metal aromatic saturation
catalyst can sometimes be similar to a lower activity hydrotreating
catalyst.
[0059] The deasphalted oil can be hydrotreated and/or hydrocracked
with little or no solvent extraction being performed prior to
and/or after the deasphalting. As a result, the deasphalted oil
feed for hydrotreatment and/or hydrocracking can have a substantial
aromatics content. In various aspects, the aromatics content of the
deasphalted oil feed can be at least 50 wt %, or at least 55 wt %,
or at least 60 wt %, or at least 65 wt %, or at least 70 wt %, or
at least 75 wt %, such as up to 90 wt % or more. Additionally or
alternately, the saturates content of the deasphalted oil feed can
be 50 wt % or less, or 45 wt % or less, or 40 wt % or less, or 35
wt % or less, or 30 wt % or less, or 25 wt % or less, such as down
to 10 wt % or less. In this discussion and the claims below, the
aromatics content and/or the saturates content of a fraction can be
determined based on ASTM D7419.
[0060] The reaction conditions during demetallization and/or
hydrotreatment and/or hydrocracking of the deasphalted oil (and
optional vacuum gas oil co-feed) can be selected to generate a
desired level of conversion of a feed. Any convenient type of
reactor, such as fixed bed (for example trickle bed) reactors can
be used. 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.
(370.degree. C.) or 1050.degree. F. (566.degree. C.). The amount of
conversion can correspond to the total conversion of molecules
within the combined hydrotreatment and hydrocracking stages for the
deasphalted oil. Suitable amounts of conversion of molecules
boiling above 1050.degree. F. (566.degree. C.) to molecules boiling
below 566.degree. C. include 30 wt % to 90 wt % conversion relative
to 566.degree. C., or 30 wt % to 80 wt %, or 30 wt % to 70 wt %, or
40 wt % to 90 wt %, or 40 wt % to 80 wt %, or 40 wt % to 70 wt %,
or 50 wt % to 90 wt %, or 50 wt % to 80 wt %, or 50 wt % to 70 wt
%. In particular, the amount of conversion relative to 566.degree.
C. can be 30 wt % to 90 wt %, or 30 wt % to 70 wt %, or 50 wt % to
90 wt %. Additionally or alternately, suitable amounts of
conversion of molecules boiling above .about.700.degree. F.
(370.degree. C.) to molecules boiling below 370.degree. C. include
10 wt % to 70 wt % conversion relative to 370.degree. C., or 10 wt
% to 60 wt %, or 10 wt % to 50 wt %, or 20 wt % to 70 wt %, or 20
wt % to 60 wt %, or 20 wt % to 50 wt %, or 30 wt % to 70 wt %, or
30 wt % to 60 wt %, or 30 wt % to 50 wt %. In particular, the
amount of conversion relative to 370.degree. C. can be 10 wt % to
70 wt %, or 20 wt % to 50 wt %, or 30 wt % to 60 wt %.
[0061] The hydroprocessed deasphalted oil can also be characterized
based on the product quality. After hydroprocessing (hydrotreating
and/or hydrocracking), the hydroprocessed deasphalted oil can have
a sulfur content of 200 wppm or less, or 100 wppm or less, or 50
wppm or less (such as down to .about.0 wppm). Additionally or
alternately, the hydroprocessed deasphalted oil can have a nitrogen
content of 200 wppm or less, or 100 wppm or less, or 50 wppm or
less (such as down to .about.0 wppm). Additionally or alternately,
the hydroprocessed deasphalted oil can have a Conradson Carbon
residue content of 1.5 wt % or less, or 1.0 wt % or less, or 0.7 wt
% or less, or 0.1 wt % or less, or 0.02 wt % or less (such as down
to .about.0 wt %). Conradson Carbon residue content can be
determined according to ASTM D4530.
[0062] In various aspects, a feed can initially be exposed to a
demetallization catalyst prior to exposing the feed to a
hydrotreating catalyst. Deasphalted oils can have metals
concentrations (Ni+V+Fe) on the order of 10-100 wppm. Exposing a
conventional hydrotreating catalyst to a feed having a metals
content of 10 wppm or more can lead to catalyst deactivation at a
faster rate than may desirable in a commercial setting. Exposing a
metal containing feed to a demetallization catalyst prior to the
hydrotreating catalyst can allow at least a portion of the metals
to be removed by the demetallization catalyst, which can reduce or
minimize the deactivation of the hydrotreating catalyst and/or
other subsequent catalysts in the process flow. Commercially
available demetallization catalysts can be suitable, such as large
pore amorphous oxide catalysts that may optionally include Group VI
and/or Group VIII non-noble metals to provide some hydrogenation
activity.
[0063] In various aspects, the deasphalted oil can be exposed to a
hydrotreating catalyst under effective hydrotreating conditions.
The catalysts used can include conventional hydroprocessing
catalysts, such as those comprising 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 optionally include 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.
Substantially carrier- or support-free catalysts, commonly referred
to as bulk catalysts, generally have higher volumetric activities
than their supported counterparts.
[0064] The catalysts can either be in bulk form or in supported
form. 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 stock) boiling range feed in a
conventional manner may be used. Preferably, the support or carrier
material is an amorphous support, such as a refractory oxide.
Preferably, the support or carrier material can be free or
substantially free of the presence of molecular sieve, where
substantially free of molecular sieve is defined as having a
content of molecular sieve of less than about 0.01 wt %.
[0065] 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.
[0066] 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 invention, 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). 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. Optionally, the hydrogen treat gas can be substantially
free (less than 1 vol %) of impurities such as H.sub.2S and
NH.sub.3 and/or such impurities can be substantially removed from a
treat gas prior to use.
[0067] Hydrogen can be supplied at a rate of from about 100 SCF/B
(standard cubic feet of hydrogen per barrel of feed) (17
Nm.sup.3/m.sup.3) to about 10000 SCF/B (1700 Nm.sup.3/m.sup.3).
Preferably, the hydrogen is provided in a range of from about 200
SCF/B (34 Nm.sup.3/m.sup.3) to about 2500 SCF/B (420
Nm.sup.3/m.sup.3). Hydrogen can be supplied co-currently with the
input feed to the hydrotreatment reactor and/or reaction zone or
separately via a separate gas conduit to the hydrotreatment
zone.
[0068] Hydrotreating conditions can include temperatures of
200.degree. C. to 450.degree. C., or 315.degree. C. to 425.degree.
C.; pressures of 250 psig (1.8 MPag) to 5000 psig (34.6 MPag) or
300 psig (2.1 MPag) to 3000 psig (20.8 MPag); 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 10,000 scf/B
(1781 m.sup.3/m.sup.3).
[0069] In various aspects, the deasphalted oil can be exposed to a
hydrocracking catalyst under effective hydrocracking conditions.
Hydrocracking catalysts typically contain sulfided base metals on
acidic supports, such as amorphous silica alumina, cracking
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 24.30 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. ZSM-48,
such as ZSM-48 with a SiO.sub.2 to Al.sub.2O.sub.3 ratio of about
110 or less, such as about 90 or less, is another example of a
potentially suitable hydrocracking catalyst. Still another option
is to use a combination of USY and ZSM-48. Still other options
include using one or more of zeolite Beta, ZSM-5, ZSM-35, or
ZSM-23, either alone or in combination with a USY 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. Additionally or alternately,
hydrocracking catalysts with noble metals can also be used.
Non-limiting examples of noble metal catalysts include those based
on platinum and/or palladium. Support materials which may be used
for both the noble and non-noble metal catalysts 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).
[0070] When only one hydrogenation metal is present on a
hydrocracking catalyst, the amount of that hydrogenation metal can
be at least about 0.1 wt % based on the total weight of the
catalyst, for example at least about 0.5 wt % or at least about 0.6
wt %. Additionally or alternately when only one hydrogenation metal
is present, the amount of that hydrogenation metal can be about 5.0
wt % or less based on the total weight of the catalyst, for example
about 3.5 wt % or less, about 2.5 wt % or less, about 1.5 wt % or
less, about 1.0 wt % or less, about 0.9 wt % or less, about 0.75 wt
% or less, or about 0.6 wt % or less. Further additionally or
alternately when more than one hydrogenation metal is present, the
collective amount of hydrogenation metals can be at least about 0.1
wt % based on the total weight of the catalyst, for example at
least about 0.25 wt %, at least about 0.5 wt %, at least about 0.6
wt %, at least about 0.75 wt %, or at least about 1 wt %. Still
further additionally or alternately when more than one
hydrogenation metal is present, the collective amount of
hydrogenation metals can be about 35 wt % or less based on the
total weight of the catalyst, for example about 30 wt % or less,
about 25 wt % or less, about 20 wt % or less, about 15 wt % or
less, about 10 wt % or less, or about 5 wt % or less. In
embodiments wherein the supported metal comprises a noble metal,
the amount of noble metal(s) is typically less than about 2 wt %,
for example less than about 1 wt %, about 0.9 wt % or less, about
0.75 wt % or less, or about 0.6 wt % or less. It is noted that
hydrocracking under sour conditions is typically performed using a
base metal (or metals) as the hydrogenation metal.
[0071] In various aspects, the conditions selected for
hydrocracking for lubricant base stock production can depend on the
desired level of conversion, the level of contaminants in the input
feed to the hydrocracking stage, and potentially other factors. For
example, hydrocracking conditions in a single stage, or in the
first stage and/or the second stage of a multi-stage system, can be
selected to achieve a desired level of conversion in the reaction
system. Hydrocracking conditions can be referred to as sour
conditions or sweet conditions, depending on the level of sulfur
and/or nitrogen present within a feed. For example, a feed with 100
wppm or less of sulfur and 50 wppm or less of nitrogen, preferably
less than 25 wppm sulfur and/or less than 10 wppm of nitrogen,
represent a feed for hydrocracking under sweet conditions. In
various aspects, hydrocracking can be performed on a thermally
cracked resid, such as a deasphalted oil derived from a thermally
cracked resid. In some aspects, such as aspects where an optional
hydrotreating step is used prior to hydrocracking, the thermally
cracked resid may correspond to a sweet feed. In other aspects, the
thermally cracked resid may represent a feed for hydrocracking
under sour conditions.
[0072] A hydrocracking process under sour conditions can be carried
out at temperatures of about 550.degree. F. (288.degree. C.) to
about 840.degree. F. (449.degree. C.), hydrogen partial pressures
of from about 1500 psig to about 5000 psig (10.3 MPag to 34.6
MPag), 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.), hydrogen partial pressures of from about 1500
psig to about 3000 psig (10.3 MPag-20.9 MPag), 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). The LHSV can be from
about 0.25h.sup.-1 to about 50 h.sup.-1, or from about 0.5h.sup.-1
to about 20 h.sup.-1, preferably from about 1.0 h.sup.-1 to about
4.0 h.sup.-1.
[0073] In some aspects, a portion of the hydrocracking catalyst can
be contained in a second reactor stage. In such aspects, a first
reaction stage of the hydroprocessing reaction system can include
one or more hydrotreating and/or hydrocracking catalysts. The
conditions in the first reaction stage can be suitable for reducing
the sulfur and/or nitrogen content of the feedstock. A separator
can then be used in between the first and second stages of the
reaction system to remove gas phase sulfur and nitrogen
contaminants. One option for the separator is to simply perform a
gas-liquid separation to remove contaminant. Another option is to
use a separator such as a flash separator that can perform a
separation at a higher temperature. Such a high temperature
separator can be used, for example, to separate the feed into a
portion boiling below a temperature cut point, such as about
350.degree. F. (177.degree. C.) or about 400.degree. F.
(204.degree. C.), and a portion boiling above the temperature cut
point. In this type of separation, the naphtha boiling range
portion of the effluent from the first reaction stage can also be
removed, thus reducing the volume of effluent that is processed in
the second or other subsequent stages. Of course, any low boiling
contaminants in the effluent from the first stage would also be
separated into the portion boiling below the temperature cut point.
If sufficient contaminant removal is performed in the first stage,
the second stage can be operated as a "sweet" or low contaminant
stage.
[0074] Still another option can be to use a separator between the
first and second stages of the hydroprocessing reaction system that
can also perform at least a partial fractionation of the effluent
from the first stage. In this type of aspect, the effluent from the
first hydroprocessing stage can be separated into at least a
portion boiling below the distillate (such as diesel) fuel range, a
portion boiling in the distillate fuel range, and a portion boiling
above the distillate fuel range. The distillate fuel range can be
defined based on a conventional diesel boiling range, such as
having a lower end cut point temperature of at least about
350.degree. F. (177.degree. C.) or at least about 400.degree. F.
(204.degree. C.) to having an upper end cut point temperature of
about 700.degree. F. (371.degree. C.) or less or 650.degree. F.
(343.degree. C.) or less. Optionally, the distillate fuel range can
be extended to include additional kerosene, such as by selecting a
lower end cut point temperature of at least about 300.degree. F.
(149.degree. C.).
[0075] In aspects where the inter-stage separator is also used to
produce a distillate fuel fraction, the portion boiling below the
distillate fuel fraction includes, naphtha boiling range molecules,
light ends, and contaminants such as H.sub.2S. These different
products can be separated from each other in any convenient manner.
Similarly, one or more distillate fuel fractions can be formed, if
desired, from the distillate boiling range fraction. The portion
boiling above the distillate fuel range represents the potential
lubricant base stocks. In such aspects, the portion boiling above
the distillate fuel range is subjected to further hydroprocessing
in a second hydroprocessing stage.
[0076] A hydrocracking process under sweet conditions can be
performed under conditions similar to those used for a sour
hydrocracking process, or the conditions can be different. In an
embodiment, the conditions in a sweet hydrocracking stage can have
less severe conditions than a hydrocracking process in a sour
stage. Suitable hydrocracking conditions for a non-sour stage can
include, but are not limited to, conditions similar to a first or
sour stage. Suitable hydrocracking conditions can include
temperatures of about 500.degree. F. (260.degree. C.) to about
840.degree. F. (449.degree. C.), hydrogen partial pressures of from
about 1500 psig to about 5000 psig (10.3 MPag to 34.6 MPag), 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.), hydrogen partial pressures of from about 1500
psig to about 3000 psig (10.3 MPag-20.9 MPag), 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). The LHSV can be from
about 0.25 h.sup.-1 to about 50 h.sup.-1, or from about 0.5
h.sup.-1 to about 20 preferably from about 1.0 h.sup.-1 to about
4.0 h.sup.-1.
[0077] In still another aspect, the same conditions can be used for
hydrotreating and hydrocracking beds or stages, such as using
hydrotreating conditions for both or using hydrocracking conditions
for both. In yet another embodiment, the pressure for the
hydrotreating and hydrocracking beds or stages can be the same.
[0078] In yet another aspect, a hydroprocessing reaction system may
include more than one hydrocracking stage. If multiple
hydrocracking stages are present, at least one hydrocracking stage
can have effective hydrocracking conditions as described above,
including a hydrogen partial pressure of at least about 1500 psig
(10.3 MPag). In such an aspect, other hydrocracking processes can
be performed under conditions that may include lower hydrogen
partial pressures. Suitable hydrocracking conditions for an
additional hydrocracking stage can include, but are not limited to,
temperatures of about 500.degree. F. (260.degree. C.) to about
840.degree. F. (449.degree. C.), hydrogen partial pressures of from
about 250 psig to about 5000 psig (1.8 MPag to 34.6 MPag), 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 for an additional hydrocracking stage can include
temperatures in the range of about 600.degree. F. (343.degree. C.)
to about 815.degree. F. (435.degree. C.), hydrogen partial
pressures of from about 500 psig to about 3000 psig (3.5 MPag-20.9
MPag), 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). The LHSV can be from about 0.25 h.sup.-1 to about 50
h.sup.-1, or from about 0.5 h.sup.-1 to about 20 h.sup.-1, and
preferably from about 1.0 h.sup.-1 to about 4.0 h.sup.-1.
Hydroprocessed Effluent--Solvent Dewaxing to form Group I Bright
Stock
[0079] The hydroprocessed deasphalted oil (optionally including
hydroprocessed vacuum gas oil) can be separated to form one or more
fuel boiling range fractions (such as naphtha or distillate fuel
boiling range fractions) and at least one lubricant base stock
boiling range fraction. The lubricant base stock boiling range
fraction(s) can then be solvent dewaxed to produce a lubricant base
stock product with a reduced (or eliminated) tendency to form haze.
Lubricant base stocks (including bright stock) formed by
hydroprocessing a deasphalted oil and then solvent dewaxing the
hydroprocessed effluent can tend to be Group I base stocks due to
having an aromatics content of at least 10 wt %.
[0080] Solvent dewaxing typically involves mixing a feed with
chilled dewaxing solvent to form an oil-solvent solution.
Precipitated wax is thereafter separated by, for example,
filtration. The temperature and solvent are selected so that the
oil is dissolved by the chilled solvent while the wax is
precipitated.
[0081] An example of a suitable solvent dewaxing process involves
the use of a cooling tower where solvent is prechilled and added
incrementally at several points along the height of the cooling
tower. The oil-solvent mixture is agitated during the chilling step
to permit substantially instantaneous mixing of the prechilled
solvent with the oil. The prechilled solvent is added incrementally
along the length of the cooling tower so as to maintain an average
chilling rate at or below 10.degree. F. per minute, usually between
about 1 to about 5.degree. F. per minute. The final temperature of
the oil-solvent/precipitated wax mixture in the cooling tower will
usually be between 0 and 50.degree. F. (-17.8 to 10.degree. C.).
The mixture may then be sent to a scraped surface chiller to
separate precipitated wax from the mixture.
[0082] Representative dewaxing solvents are aliphatic ketones
having 3-6 carbon atoms such as methyl ethyl ketone and methyl
isobutyl ketone, low molecular weight hydrocarbons such as propane
and butane, and mixtures thereof. The solvents may be mixed with
other solvents such as benzene, toluene or xylene.
[0083] In general, the amount of solvent added will be sufficient
to provide a liquid/solid weight ratio between the range of 5/1 and
20/1 at the dewaxing temperature and a solvent/oil volume ratio
between 1.5/1 to 5/1. The solvent dewaxed oil can be dewaxed to a
pour point of -6.degree. C. or less, or -10.degree. C. or less, or
-15.degree. C. or less, depending on the nature of the target
lubricant base stock product. Additionally or alternately, the
solvent dewaxed oil can be dewaxed to a cloud point of -2.degree.
C. or less, or -5.degree. C. or less, or -10.degree. C. or less,
depending on the nature of the target lubricant base stock product.
The resulting solvent dewaxed oil can be suitable for use in
forming one or more types of Group I base stocks. Preferably, a
bright stock formed from the solvent dewaxed oil can have a cloud
point below -5.degree. C. The resulting solvent dewaxed oil can
have a viscosity index of at least 90, or at least 95, or at least
100. Preferably, at least 10 wt % of the resulting solvent dewaxed
oil (or at least 20 wt %, or at least 30 wt %) can correspond to a
Group I bright stock having a kinematic viscosity at 100.degree. C.
of at least 15 cSt, or at least 20 cSt, or at least 25 cSt, such as
up to 50 cSt or more.
[0084] In some aspects, the reduced or eliminated tendency to form
haze for the lubricant base stocks formed from the solvent dewaxed
oil can be demonstrated by a reduced or minimized difference
between the cloud point temperature and pour point temperature for
the lubricant base stocks. In various aspects, the difference
between the cloud point and pour point for the resulting solvent
dewaxed oil and/or for one or more lubricant base stocks, including
one or more bright stocks, formed from the solvent dewaxed oil, can
be 22.degree. C. or less, or 20.degree. C. or less, or 15.degree.
C. or less, or 10.degree. C. or less, or 8.degree. C. or less, or
5.degree. C. or less. Additionally or alternately, a reduced or
minimized tendency for a bright stock to form haze over time can
correspond to a bright stock having a cloud point of -10.degree. C.
or less, or -8.degree. C. or less, or -5.degree. C. or less, or
-2.degree. C. or less.
Additional Hydroprocessing--Catalytic Dewaxing, Hydrofinishing, and
Optional Hydrocracking
[0085] In some alternative aspects, at least a lubricant boiling
range portion of the hydroprocessed deasphalted oil can be exposed
to further hydroprocessing (including catalytic dewaxing) to form
either Group I and/or Group II base stocks, including Group I
and/or Group II bright stock. In some aspects, a first lubricant
boiling range portion of the hydroprocessed deasphalted oil can be
solvent dewaxed as described above while a second lubricant boiling
range portion can be exposed to further hydroprocessing. In other
aspects, only solvent dewaxing or only further hydroprocessing can
be used to treat a lubricant boiling range portion of the
hydroprocessed deasphalted oil.
[0086] Optionally, the further hydroprocessing of the lubricant
boiling range portion of the hydroprocessed deasphalted oil can
also include exposure to hydrocracking conditions before and/or
after the exposure to the catalytic dewaxing conditions. At this
point in the process, the hydrocracking can be considered "sweet"
hydrocracking, as the hydroprocessed deasphalted oil can have a
sulfur content of 200 wppm or less.
[0087] Suitable hydrocracking conditions can include exposing the
feed to a hydrocracking catalyst as previously described above.
Optionally, it can be preferable to use a USY zeolite with a silica
to alumina ratio of at least 30 and a unit cell size of less than
24.32 Angstroms as the zeolite for the hydrocracking catalyst, in
order to improve the VI uplift from hydrocracking and/or to improve
the ratio of distillate fuel yield to naphtha fuel yield in the
fuels boiling range product.
[0088] Suitable hydrocracking conditions can also include
temperatures of about 500.degree. F. (260.degree. C.) to about
840.degree. F. (449.degree. C.), hydrogen partial pressures of from
about 1500 psig to about 5000 psig (10.3 MPag to 34.6 MPag), 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.), hydrogen partial pressures of from about 1500
psig to about 3000 psig (10.3 MPag-20.9 MPag), 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). The LHSV can be from
about 0.25 h.sup.-1 to about 50 h.sup.-1, or from about 0.5
h.sup.-1 to about 20 h.sup.-1, and preferably from about 1.0
h.sup.-1 to about 4.0 h.sup.-1.
[0089] For catalytic dewaxing, suitable dewaxing catalysts can
include molecular sieves such as crystalline aluminosilicates
(zeolites). In an embodiment, the molecular sieve can comprise,
consist essentially of, or be ZSM-22, ZSM-23, ZSM-48. Optionally
but preferably, molecular sieves that are selective for dewaxing by
isomerization as opposed to cracking can be used, such as ZSM-48,
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, such as 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.
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.
[0090] Preferably, the dewaxing catalysts used in processes
according to the invention 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 about 100:1 or less, such as about 90:1 or
less, or about 75:1 or less, or about 70:1 or less. Additionally or
alternately, the ratio of silica to alumina in the ZSM-48 can be at
least about 50:1, such as at least about 60:1, or at least about
65:1.
[0091] In various embodiments, the catalysts according to the
invention 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 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.
[0092] 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.
[0093] The amount of metal in the catalyst can be at least 0.1 wt %
based on catalyst, or at least 0.5 wt %, or at least 1.0 wt %, or
at least 2.5 wt %, or at least 5.0 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 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 %.
[0094] The dewaxing catalysts useful in processes according to the
invention can also include a binder. In some embodiments, the
dewaxing catalysts used in process according to the invention are
formulated using a low surface area binder, a low surface area
binder represents a binder with a surface area of 100 m.sup.2/g or
less, or 80 m.sup.2/g or less, or 70 m.sup.2/g or less.
Additionally or alternately, the binder can have a surface area of
at least about 25 m.sup.2/g. The amount of zeolite in a catalyst
formulated using a binder can be from about 30 wt % zeolite to 90
wt % zeolite relative to the combined weight of binder and zeolite.
Preferably, the amount of zeolite is at least about 50 wt % of the
combined weight of zeolite and binder, such as at least about 60 wt
% or from about 65 wt % to about 80 wt %.
[0095] Without being bound by any particular theory, it is believed
that use of a low surface area binder reduces the amount of binder
surface area available for the hydrogenation metals supported on
the catalyst. This leads to an increase in the amount of
hydrogenation metals that are supported within the pores of the
molecular sieve in the catalyst.
[0096] A zeolite can be combined with binder in any convenient
manner. For example, a bound catalyst can be produced by starting
with powders of both the zeolite and binder, combining and mulling
the powders with added water to form a mixture, and then extruding
the mixture to produce a bound catalyst of a desired size.
Extrusion aids can also be used to modify the extrusion flow
properties of the zeolite and binder mixture. The amount of
framework alumina in the catalyst may range from 0.1 to 3.33 wt %,
or 0.1 to 2.7 wt %, or 0.2 to 2 wt %, or 0.3 to 1 wt %.
[0097] Effective conditions for catalytic dewaxing of a feedstock
in the presence of a dewaxing catalyst can include a temperature of
from 280.degree. C. to 450.degree. C., preferably 343.degree. C. to
435.degree. C., a hydrogen partial pressure of from 3.5 MPag to
34.6 MPag (500 psig to 5000 psig), preferably 4.8 MPag to 20.8
MPag, and a hydrogen circulation rate of from 178 m.sup.3/m.sup.3
(1000 SCF/B) to 1781 m.sup.3/m.sup.3 (10,000 scf/B), preferably 213
m.sup.3/m.sup.3 (1200 SCF/B) to 1068 m.sup.3/m.sup.3 (6000 SCF/B).
The LHSV can be from about 0.2 to about 10 h.sup.-1, such as from
about 0.5 h.sup.-1 to about 5 and/or from about 1 h.sup.-1 to about
4 h.sup.-1.
[0098] Before and/or after catalytic dewaxing, the hydroprocessed
deasphalted oil (i.e., at least a lubricant boiling range portion
thereof) can optionally be exposed to an aromatic saturation
catalyst, which can alternatively be referred to as a
hydrofinishing catalyst. Exposure to the aromatic saturation
catalyst can occur either before or after fractionation. If
aromatic saturation occurs after fractionation, the aromatic
saturation can be performed on one or more portions of the
fractionated product. Alternatively, the entire effluent from the
last hydrocracking or dewaxing process can be hydrofinished and/or
undergo aromatic saturation.
[0099] 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. For supported hydrotreating catalysts, 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 crystalline 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.
[0100] 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 Processing of Catalytically Dewaxed Effluent or Input Flow
to Catalytic Dewaxing
[0101] For deasphalted oils derived from propane deasphalting, the
further hydroprocessing (including catalytic dewaxing) can be
sufficient to form bright stocks with low haze formation and
unexpected compositional properties. For deasphalted oils derived
from C.sub.4+ deasphalting, after the further hydroprocessing
(including catalytic dewaxing), the heavy portion of the resulting
catalytically dewaxed effluent can be solvent processed to form one
or more lubricant bright stock products with a reduced or
eliminated tendency to form haze. The type of solvent processing
can be dependent on the nature of the initial hydroprocessing
(hydrotreatment and/or hydrocracking) and the nature of the further
hydroprocessing (including dewaxing). The heavy neutral and light
neutral base stock products can be suitable for use (i.e., no haze
formation) without further solvent processing.
[0102] In aspects where the initial hydroprocessing is less severe,
corresponding to 10 wt % to 40 wt % conversion relative to
.about.700.degree. F. (370.degree. C.), the subsequent solvent
processing for bright stock formation can correspond to solvent
dewaxing. The solvent dewaxing can be performed in a manner similar
to the solvent dewaxing described above. However, this solvent
dewaxing can be used to produce a Group II lubricant base stock. In
some aspects, when the initial hydroprocessing corresponds to 10 wt
% to 40 wt % conversion relative to 370.degree. C., the catalytic
dewaxing during further hydroprocessing can also be performed at
lower severity, so that at least 6 wt % wax remains in the
catalytically dewaxed effluent, or at least 8 wt %, or at least 10
wt %, or at least 12 wt %, or at least 15 wt %, such as up to 20 wt
%. The solvent dewaxing can then be used to reduce the wax content
in the catalytically dewaxed effluent by 2 wt % to 10 wt %. This
can produce a solvent dewaxed oil product having a wax content of
0.1 wt % to 12 wt %, or 0.1 wt % to 10 wt %, or 0.1 wt % to 8 wt %,
or 0.1 wt % to 6 wt %, or 1 wt % to 12 wt %, or 1 wt % to 10 wt %,
or 1 wt % to 8 wt %, or 4 wt % to 12 wt %, or 4 wt % to 10 wt %, or
4 wt % to 8 wt %, or 6 wt % to 12 wt %, or 6 wt % to 10 wt %. In
particular, the solvent dewaxed oil can have a wax content of 0.1
wt % to 12 wt %, or 0.1 wt % to 6 wt %, or 1 wt % to 10 wt %, or 4
wt % to 12 wt %.
[0103] In other aspects, the subsequent solvent processing for
bright stock formation can correspond to solvent extraction.
Solvent extraction can be used to reduce the aromatics content
and/or the amount of polar molecules. 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. By controlling the solvent to oil ratio,
extraction temperature and method of contacting distillate to be
extracted with solvent, one can 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. Depending on the initial concentration of
aromatics in the deasphalted oil, the raffinate phase can have an
aromatics content of 5 wt % to 25 wt %. For typical feeds, the
aromatics contents can be at least 10 wt %.
[0104] Optionally, the raffinate from the solvent extraction can be
under-extracted. In such aspects, the extraction is carried out
under conditions such that the raffinate yield is maximized while
still removing most of the lowest quality molecules from the feed.
Raffinate yield may be maximized by controlling extraction
conditions, for example, by lowering the solvent to oil treat ratio
and/or decreasing the extraction temperature. In various aspects,
the raffinate yield from solvent extraction can be at least 40 wt
%, or at least 50 wt %, or at least 60 wt %, or at least 70 wt
%.
[0105] The solvent processed oil (solvent dewaxed or solvent
extracted) can have a pour point of -6.degree. C. or les, or
-10.degree. C. or less, or -15.degree. C. or less, or -20.degree.
C. or less, depending on the nature of the target lubricant base
stock product. Additionally or alternately, the solvent processed
oil (solvent dewaxed or solvent extracted) can have a cloud point
of -2.degree. C. or less, or -5.degree. C. or less, or -10.degree.
C. or less, depending on the nature of the target lubricant base
stock product. Pour points and cloud points can be determined
according to ASTM D97 and ASTM D2500, respectively. The resulting
solvent processed oil can be suitable for use in forming one or
more types of Group II base stocks. The resulting solvent dewaxed
oil can have a viscosity index of at least 80, or at least 90, or
at least 95, or at least 100, or at least 110, or at least 120.
Viscosity index can be determined according to ASTM D2270.
Preferably, at least 10 wt % of the resulting solvent processed oil
(or at least 20 wt %, or at least 30 wt %) can correspond to a
Group II bright stock having a kinematic viscosity at 100.degree.
C. of at least 14 cSt, or at least 15 cSt, or at least 20 cSt, or
at least 25 cSt, or at least 30 cSt, or at least 32 cSt, such as up
to 50 cSt or more. Additionally or alternately, the Group II bright
stock can have a kinematic viscosity at 40.degree. C. of at least
300 cSt, or at least 320 cSt, or at least 340 cSt, or at least 350
cSt, such as up to 500 cSt or more. Kinematic viscosity can be
determined according to ASTM D445. Additionally or alternately, the
Conradson Carbon residue content can be about 0.1 wt % or less, or
about 0.02 wt % or less. Conradson Carbon residue content can be
determined according to ASTM D4530. Additionally or alternately,
the resulting base stock can have a turbidity of at least 1.5 (in
combination with a cloud point of less than 0.degree. C.), or can
have a turbidity of at least 2.0, and/or can have a turbidity of
4.0 or less, or 3.5 or less, or 3.0 or less. In particular, the
turbidity can be 1.5 to 4.0, or 1.5 to 3.0, or 2.0 to 4.0, or 2.0
to 3.5.
[0106] The reduced or eliminated tendency to form haze for the
lubricant base stocks formed from the solvent processed oil can be
demonstrated by the reduced or minimized difference between the
cloud point temperature and pour point temperature for the
lubricant base stocks. In various aspects, the difference between
the cloud point and pour point for the resulting solvent dewaxed
oil and/or for one or more Group II lubricant base stocks,
including one or more bright stocks, formed from the solvent
processed oil, can be 22.degree. C. or less, or 20.degree. C. or
less, or 15.degree. C. or less, or 10.degree. C. or less, such as
down to about 1.degree. C. of difference.
[0107] In some alternative aspects, the above solvent processing
can be performed prior to catalytic dewaxing.
Group II Base Stock Products
[0108] For deasphalted oils derived from propane, butane, pentane,
hexane and higher or mixtures thereof, the further hydroprocessing
(including catalytic dewaxing) and potentially solvent processing
can be sufficient to form lubricant bright stocks with low haze
formation (or no haze formation) and novel compositional
properties. Traditional products manufactured today with kinematic
viscosity of about 32 cSt at 100.degree. C. contain aromatics that
are >10% and/or sulfur that is >0.03% of the base oil. Such
bright stocks can have a kinematic viscosity of at least 14 cSt, or
at least 20 cSt, or at least 25 cSt, or at least 30 cSt, or at
least 32 cSt at 100.degree. C. and can contain less than 10 wt %
aromaticsgreater than 90 wt % saturates and less than 0.03%
sulfur.
[0109] During block processing, heavy neutral and light neutral
products can also be formed. For base stocks produced during a
light neutral or heavy neutral production block, the resulting base
stocks can be produced without subsequent solvent processing while
having substantially no haze formation. The light neutral base
stocks can have, for example, a kinematic viscosity at 100.degree.
C. of 3.5 cSt to 6.5 cSt, or 4.0 cSt to 6.0 cSt. The heavy neutral
base stocks can have, for example, a kinematic viscosity at
100.degree. C. of 8.0 cSt to 15 cSt, or 9.0 cSt to 14 cSt. The
heavy neutral and light neutral base stocks can have a saturates
content of 90 wt % or more, or 95 wt % or more, or 98 wt % or more,
or 99 wt % or more.
[0110] A formulated lubricating oil useful in the present
disclosure may contain one or more of the other commonly used
lubricating oil performance additives including but not limited to
antiwear additives, detergents, dispersants, viscosity modifiers,
corrosion inhibitors, rust inhibitors, metal deactivators, extreme
pressure additives, anti-seizure agents, wax modifiers, other
viscosity modifiers, fluid-loss additives, seal compatibility
agents, lubricity agents, anti-staining agents, chromophoric
agents, defoamants, demulsifiers, emulsifiers, densifiers, wetting
agents, gelling agents, tackiness agents, colorants, and others.
For a review of many commonly used additives, see "Lubricant
Additives, Chemistry and Applications", Ed. L. R. Rudnick, Marcel
Dekker, Inc. 270 Madison Ave. New York, N.J. 10016, 2003, and
Klamann in Lubricants and Related Products, Verlag Chemie,
Deerfield Beach, Fla.; ISBN 0-89573-177-0. Reference is also made
to "Lubricant Additives" by M. W. Ranney, published by Noyes Data
Corporation of Parkridge, N.J. (1973); see also U.S. Pat. No.
7,704,930, the disclosure of which is incorporated herein in its
entirety. These additives are commonly delivered with varying
amounts of diluent oil that may range from 5 weight percent to 50
weight percent.
[0111] The additives useful in this disclosure do not have to be
soluble in the lubricating oils. Insoluble additives such as zinc
stearate in oil can be dispersed in the lubricating oils of this
disclosure.
[0112] When lubricating oil compositions contain one or more
additives, the additive(s) are blended into the composition in an
amount sufficient for it to perform its intended function.
Additives are typically present in lubricating oil compositions as
a minor component, typically in an amount of less than 50 weight
percent, preferably less than about 30 weight percent, and more
preferably less than about 15 weight percent, based on the total
weight of the composition. Additives are most often added to
lubricating oil compositions in an amount of at least 0.1 weight
percent, preferably at least 1 weight percent, more preferably at
least 5 weight percent. Typical amounts of such additives useful in
the present disclosure are shown in Table 1 below.
[0113] It is noted that many of the additives are shipped from the
additive manufacturer as a concentrate, containing one or more
additives together, with a certain amount of base oil diluents.
Accordingly, the weight amounts in the Table A below, as well as
other amounts mentioned herein, are directed to the amount of
active ingredient (that is the non-diluent portion of the
ingredient). The weight percent (wt %) indicated below is based on
the total weight of the lubricating oil composition.
TABLE-US-00001 TABLE A Typical Amounts of Other Lubricating Oil
Components Approximate Approximate Compound wt % (Useful) wt %
(Preferred) Dispersant 0.1-20 0.1-8 Detergent 0.1-20 0.1-8 Friction
Modifier 0.01-5 0.01-1.5 Antioxidant 0.1-5 0.1-1.5 Pour Point
Depressant 0.0-5 0.01-1.5 (PPD) Anti-foam Agent 0.001-3 0.001-0.15
Viscosity Modifier (solid 0.1-2 0.1-1 polymer basis) Antiwear 0.2-3
0.5-1 Inhibitor and Antirust 0.01-5 0.01-1.5
[0114] The foregoing additives are all commercially available
materials. These additives may be added independently but are
usually precombined in packages which can be obtained from
suppliers of lubricant oil additives. Additive packages with a
variety of ingredients, proportions and characteristics are
available and selection of the appropriate package will take the
requisite use of the ultimate composition into account.
[0115] The lube base stocks of the present disclosure are well
suited as lube base stocks without blending limitations, and
further, the lube base stock products are also compatible with
lubricant additives for lubricant formulations. The lube base
stocks of the present disclosure can optionally be blended with
other lube base stocks to form lubricants. Useful cobase lube
stocks include Group I, III, IV and V base stocks and gas-to-liquid
(GTL) oils. One or more of the cobase stocks may be blended into a
lubricant composition including the lube base stock at from 0.1 to
50 wt. %, or 0.5 to 40 wt. %, 1 to 35 wt. %, or 2 to 30 wt. %, or 5
to 25 wt. %, or 10 to 20 wt. %, based on the total lubricant
composition.
[0116] The lube base stocks and lubricant compositions can be
employed in the present disclosure in a variety of
lubricant-related end uses, such as a lubricant oil or grease for a
device or apparatus requiring lubrication of moving and/or
interacting mechanical parts, components, or surfaces. Useful
apparatuses include engines and machines. The lube base stocks of
the present disclosure are most suitable for use in the formulation
of automotive crank case lubricants, automotive gear oils,
transmission oils, many industrial lubricants including circulation
lubricant, industrial gear lubricants, grease, compressor oil, pump
oils, refrigeration lubricants, hydraulic lubricants, metal working
fluids.
CONFIGURATION EXAMPLES
[0117] FIGS. 1 to 3 show examples of using blocked operation and/or
partial product recycle during lubricant production based on a feed
including deasphalted resid. In FIGS. 1 to 3, after initial sour
stage processing, the hydroprocessed effluent is fractionated to
form light neutral, heavy neutral, and brightstock portions. FIG. 1
shows an example of the process flow during processing to form
light neutral base stock. FIG. 2 shows an example of the process
flow during processing to form heavy neutral base stock. FIG. 3
shows an example of the process flow during processing to form
brightstock.
[0118] In FIG. 1, a feed 705 is introduced into a deasphalter 710.
The deasphalter 710 generates a deasphalted oil 715 and deasphalter
rock or residue 718. The deasphalted oil 715 is then processed in a
sour processing stage 720. Optionally, a portion 771 of recycled
light neutral base product 762 can be combined with deasphalted oil
715. Sour processing stage 720 can include one or more of a
deasphalting catalyst, a hydrotreating catalyst, a hydrocracking
catalyst, and/or an aromatic saturation catalyst. The conditions in
sour processing stage 720 can be selected to at least reduce the
sulfur content of the hydroprocessed effluent 725 to 20 wppm or
less. This can correspond to 15 wt % to 40 wt % conversion of the
feed relative to 370.degree. C. Optionally, the amount of
conversion in the sour processing stage 720 can be any convenient
higher amount so long as the combined conversion in sour processing
stage 720 and sweet processing stage 750 is 90 wt % or less.
[0119] The hydroprocessed effluent 725 can then be passed into
fractionation stage 730 for separation into a plurality of
fractions. In the example shown in FIG. 1, the hydroprocessed
effluent is separated into a light neutral portion 732, a heavy
neutral portion 734, and a brightstock portion 736. To allow for
blocked operation, the light neutral portion 732 can be sent to
corresponding light neutral storage 742, the heavy neutral portion
734 can be sent to corresponding heavy neutral storage 744, and the
brightstock portion 736 can be sent to corresponding brightstock
storage 746. A lower boiling range fraction 731 corresponding to
fuels and/or light ends can also be generated by fractionation
stage 730. Optionally, fractionation stage can generate a plurality
of lower boiling range fractions 731.
[0120] FIG. 1 shows an example of the processing system during a
light neutral processing block. In FIG. 1, the feed 752 to sweet
processing stage 750 corresponds to a feed derived from light
neutral storage 742. The sweet processing stage 750 can include at
least dewaxing catalyst, and optionally can further include one or
more of hydrocracking catalyst and aromatics saturation catalyst.
The dewaxed effluent 755 from sweet processing stage 750 can then
be passed into a fractionator 760 to form light neutral base stock
product 762. A lower boiling fraction 761 corresponding to fuels
and/or light ends can also be separated out by fractionator 760.
Optionally, a portion of light neutral base stock 762 can be
recycled. The recycled portion of light neutral base stock 762 can
be used as a recycled feed portion 771 and/or as a recycled portion
772 that is added to light neutral storage 742. Recycling a portion
771 for use as part of the feed can be beneficial for increasing
the lifetime of the catalysts in sour processing stage 720.
Recycling a portion 772 to light neutral storage 742 can be
beneficial for increasing conversion and/or VI.
[0121] FIG. 2 shows the same processing configuration during
processing of a heavy neutral block. In FIG. 2, the feed 754 to
sweet processing stage 750 is derived from heavy neutral storage
744. The dewaxed effluent 755 from sweet processing stage 750 can
be fractionated 760 to form lower boiling portion 761, heavy
neutral base stock product 764, and light neutral base stock
product 762. Because block operation to form a heavy neutral base
stock results in production of both a light neutral product 762 and
a heavy neutral product 764, various optional recycle streams can
also be used. In the example shown in FIG. 2, optional recycle
portions 771 and 772 can be used for recycle of the light neutral
product 762. Additionally, optional recycle portions 781 and 784
can be used for recycle of the heavy neutral product 764. Recycle
portions 781 and 784 can provide similar benefits to those for
recycle portions 771 and/or 772.
[0122] FIG. 3 shows the same processing configuration during
processing of a bright stock block. In FIG. 3, the feed 756 to
sweet processing stage 750 is derived from bright stock storage
746. The dewaxed effluent 755 from sweet processing stage 750 can
be fractionated 760 to form lower boiling portion 761, bottoms
product 766, heavy neutral base stock product 764, and light
neutral base stock product 762. Bottoms product 766 can then be
extracted 790 to form a bright stock product 768. The aromatic
extract 793 produced in extractor 790 can be recycled for use, for
example, as part of the feed to deasphalter 710.
[0123] Because block operation to form a bright stock results in
production of a bright stock product 768 as well as a light neutral
product 762 and a heavy neutral product 764, various optional
recycle streams can also be used. In the example shown in FIG. 3,
optional recycle portions 771 and 772 can be used for recycle of
the light neutral product 762, while optional recycle portions 781
and 784 can be used for recycle of the heavy neutral product 764.
Additionally, optional recycle portions 791 and 796 can be used for
recycle of the bottoms product 766. Recycle portions 791 and 796
can provide similar benefits to those for recycle portions 771,
772, 781, and/or 784.
Example 1
[0124] In this example, a deasphalted oil was generated based on
high lift deasphalting using a C.sub.5 deasphalting solvent. The
deasphalted oil was processed in a two-stage reaction system. In a
first stage under sour conditions, the deasphalted oil was exposed
to a demetallization catalyst, a hydrotreating catalyst, and a
hydrocracking catalyst. The first stage effluent was then separated
to remove fuels (and lower) boiling range fractions from a
370.degree. C.+ portion of the first stage effluent. The separation
further provided for separation of the 370.degree. C.+ portion into
feeds for light neutral base stock production, heavy neutral base
stock production, and bright stock production. The feeds derived
from the 370.degree. C.+ portion of the first stage effluent were
then exposed to an aromatic saturation catalyst, a hydrocracking
catalyst, a dewaxing catalyst, and another portion of the aromatic
saturation catalyst in a second (sweet) reaction stage. The
aromatic saturation catalyst was a commercially available aromatic
saturation catalyst including Pt on a mixed metal oxide. The
dewaxing catalyst was a catalyst that dewaxes primarily by
isomerization, and also included supported Pt. The hydrocracking
catalyst included Pt on a support including USY. The second stage
was operated under blocked operating conditions, to allow for
selection of separate processing conditions for each of the types
of 370.degree. C.+ feeds (light neutral, heavy neutral, bright
stock).
[0125] The deasphalted oil feed introduced into the first (sour)
stage had a density at 15.degree. C. of 0.9843 g/cm.sup.3; an API
gravity of 12.3; a hydrogen content of 10.76 wt %; a sulfur content
of 3.5 wt %; a nitrogen content of 2562 wppm; a kinematic viscosity
at 100.degree. C. of 181 cSt; a viscosity index of 74; a T10
distillation point of 494.degree. C.; and a T90 distillation point
of 724.degree. C.
[0126] The deasphalted oil was exposed to the catalysts in the sour
stage under conditions sufficient for performing 48 wt % conversion
on the feed relative to a temperature of 370.degree. C. For the
370.degree. C.+ portion of the effluent, 17 wt % (relative to the
weight of the total effluent) corresponded to a feed for light
neutral production having a kinematic viscosity at 100.degree. C.
of 5.4 cSt and a viscosity index of 117; 14 wt % corresponded to a
feed for heavy neutral production having a kinematic viscosity at
100.degree. C. of 11.1 cSt and a viscosity index of 114; and 21 wt
% corresponded to a feed for bright stock production having a
kinematic viscosity at 100.degree. C. of 33.6 cSt and a viscosity
index of 116. The sulfur content of the liquid portions of the sour
stage effluent was 10 wppm or less. The sulfur content of each of
the 370.degree. C.+ fractions produced was also 10 wppm or
less.
[0127] The 370.degree. C.+ fractions were then further processed in
the second (sweet) reaction stage. The bright stock feed was
processed under two different sets of reaction conditions to form
bright stock products from lower severity and higher severity
processing.
[0128] Light Neutral Feed--The light neutral feed introduced into
the second (sweet) stage had a density at 15.degree. C. of 0.8128
g/cm.sup.3; an API gravity of 31.9; a hydrogen content of 13.6 wt
%; a sulfur content of less than 5 wppm; a nitrogen content of 3
wppm; a kinematic viscosity at 100.degree. C. of 5.4 cSt; a
viscosity index of 117; a T10 distillation point of 385.degree. C.;
and a T90 distillation point of 488.degree. C.
[0129] The light neutral feed was exposed to the catalysts in the
sweet stage under conditions sufficient for performing roughly 24
wt % conversion on the feed relative to a temperature of
370.degree. C. After separation of fuels (and lower) boiling range
components, roughly a 76 wt % yield of light neutral base stock was
formed relative to a weight of the light neutral feed. A cut point
of 378.degree. C. was used for separating diesel fuel from the
light neutral base stock in order to achieve a desired viscosity.
The light neutral base stock had a T10 distillation point of
386.degree. C.; a T90 distillation point of 492.degree. C.; a
kinematic viscosity at 100.degree. C. of 5.7 cSt; a viscosity index
of 110; a pour point of -22.degree. C.; a cloud point of
-20.degree. C.; and an API gravity of 32.9. The saturates content
was at least 99 wt %.
[0130] Heavy Neutral Feed--The heavy neutral feed introduced into
the second (sweet) stage had a density at 15.degree. C. of 0.819
g/cm.sup.3; an API gravity of 31.1; a hydrogen content of 13.7 wt
%; a sulfur content of less than 5 wppm; a nitrogen content of 3
wppm; a kinematic viscosity at 100.degree. C. of 11.1 cSt; a
viscosity index of 114; a T10 distillation point of 447.degree. C.;
and a T90 distillation point of 565.degree. C.
[0131] The heavy neutral feed was exposed to the catalysts in the
sweet stage under conditions sufficient for performing roughly 10
wt % conversion on the feed relative to a temperature of
370.degree. C. After separation of fuels (and lower) boiling range
components, roughly a 85 wt % yield of heavy neutral base stock was
formed relative to a weight of the heavy neutral feed. A cut point
of 418.degree. C. was used for separating diesel fuel from the
heavy neutral base stock in order to achieve a desired viscosity.
It is noted that an additional light neutral base stock fraction
could have been produced from a heavy portion of the diesel fuel
cut. The heavy neutral base stock had a T10 distillation point of
452.degree. C.; a T90 distillation point of 559.degree. C.; a
kinematic viscosity at 100.degree. C. of 12.0 cSt; a viscosity
index of 105; a pour point of -18.degree. C.; a cloud point of
-9.degree. C.; and an API gravity of 31.3. The saturates content
was at least 99 wt %.
[0132] Bright Stock Feed (Low Conversion)--In one example, the
bright stock feed was processed under low conversion conditions in
the second stage. The bright stock introduced into the second
(sweet) stage had a density at 15.degree. C. of 0.830 g/cm.sup.3;
an API gravity of 29.4; a hydrogen content of 13.7 wt %; a sulfur
content of 9 wppm; a nitrogen content of 3 wppm; a micro carbon
residue content of 0.02 wt %; a kinematic viscosity at 100.degree.
C. of 33.6 cSt; a viscosity index of 117; a T10 distillation point
of 552.degree. C.; and a T90 distillation point of 690.degree.
C.
[0133] The bright stock feed was exposed to the catalysts in the
sweet stage under conditions sufficient for performing roughly 22
wt % conversion on the feed relative to a temperature of
370.degree. C. After separation of fuels (and lower) boiling range
components, roughly a 73 wt % yield of bright stock was formed
relative to a weight of the bright stock feed. Additionally, 5.5 wt
% of a light neutral base stock was formed. A cut point of
368.degree. C. was used for separating diesel fuel from the
additional light neutral base stock. The bright stock produced
under the low conversion conditions had a T10 distillation point of
517.degree. C.; a T90 distillation point of 681.degree. C.; a
kinematic viscosity at 100.degree. C. of 32.0 cSt; a viscosity
index of 102; a pour point of -32.degree. C.; a cloud point of
-33.degree. C.; and an API gravity of 29.6. The saturates content
was at least 99 wt %.
[0134] It is noted that the bright stock produced under low
conversion conditions in the second stage demonstrated an
unexpected property in the form of having a cloud point that was
lower than the pour point. This type of unexpected reversal of the
ordering of the cloud point and pour point for a bright stock could
potentially be beneficial for low temperature applications where
bright stock is desirable.
[0135] The additional light neutral base stock produced under the
low conversion conditions had a T10 distillation point of
363.degree. C.; a T90 distillation point of 486.degree. C.; a
kinematic viscosity at 100.degree. C. of 5.3 cSt; a viscosity index
of 100; a pour point of -58.degree. C.; and an API gravity of 33.2.
The saturates content was at least 98 wt %.
[0136] Bright Stock Feed (High Conversion)--In another example, the
bright stock feed was processed under higher conversion conditions
in the second stage. The bright stock introduced into the second
(sweet) stage had a density at 15.degree. C. of 0.830 g/cm.sup.3;
an API gravity of 29.4; a hydrogen content of 13.7 wt %; a sulfur
content of 9 wppm; a nitrogen content of 3 wppm; a micro carbon
residue content of 0.02 wt %; a kinematic viscosity at 100.degree.
C. of 33.6 cSt; a viscosity index of 117; a T10 distillation point
of 552.degree. C.; and a T90 distillation point of 690.degree.
C.
[0137] The bright stock feed was exposed to the catalysts in the
sweet stage under conditions sufficient for performing roughly 44
wt % conversion on the feed relative to a temperature of
370.degree. C. After separation of fuels (and lower) boiling range
components, roughly a 47 wt % yield of bright stock was formed
relative to a weight of the bright stock feed. Additionally, 4.1 wt
% of a light neutral base stock was formed. A cut point of
416.degree. C. was used for separating diesel fuel from the
additional light neutral base stock. The bright stock produced
under the low conversion conditions had a T10 distillation point of
518.degree. C.; a T90 distillation point of 678.degree. C.; a
kinematic viscosity at 100.degree. C. of 34.8 cSt; a viscosity
index of 100; a pour point of -27.degree. C.; a cloud point of
-60.degree. C.; and an API gravity of 29.6. The saturates content
was at least 99 wt %. Based on the differences between the bright
stock properties for a similar boiling range, it appears that
increasing the conversion in the second stage allowed for
production of a bright stock with a lower cloud point, a lower
viscosity index, and a higher kinematic viscosity at 100.degree.
C.
[0138] The additional light neutral base stock produced under the
high conversion conditions had a T10 distillation point of
382.degree. C.; a T90 distillation point of 503.degree. C.; a
kinematic viscosity at 100.degree. C. of 6.0 cSt; a viscosity index
of 104; a pour point of lower than -50.degree. C.; and an API
gravity of 34.4. The saturates content was at least 98 wt %.
Example 2
[0139] A configuration similar to the configuration shown in FIGS.
1 to 3 was used to process a resid-type feed that substantially
included 510.degree. C.+ components. The configuration for this
example did not include recycle products as part of the feed for
the sour stage or for further sweet stage processing. The feed was
initially deasphalted using n-pentane to produce 75 wt %
deasphalted oil and 25 wt % deasphalter rock or residue. The
resulting deasphalted oil had an API gravity of 12.3, a sulfur
content of 3.46 wt %, a nitrogen content of 2760 wppm, and a micro
carbon residue content of roughly 12 wt %. The deasphalted oil was
then hydroprocessed in an initial sour hydroprocessing stage that
included four catalyst beds. The first two catalyst beds (in a
first reactor) corresponded to commercially available
demetallization catalysts. The third catalyst bed (in a second
reactor) corresponded to a mixture of hydrotreating catalysts,
including 14 vol % of a bulk metal hydrotreating catalyst. The
fourth catalyst bed included a commercially available hydrocracking
catalyst. The effluent from each catalyst bed was cascaded to the
next catalyst bed. The average reaction temperature across each
catalyst bed was 378.degree. C. for the first demetallization
catalyst bed, 388.degree. C. for the second demetallization
catalyst bed, 389.degree. C. for the hydrotreating catalyst bed,
and 399.degree. C. for the hydrocracking catalyst bed. The flow
rate of the feed relative to the total volume of catalyst in the
sour hydroprocessing stage was an LHSV of 0.16 hr.sup.-1. The
hydrogen partial pressure was 2500 psia (17.2 MPa-a) and the
hydrogen treat gas flow rate was 8000 scf/b (.about.1420
Nm.sup.3/m.sup.3). Under these conditions, the hydroprocessing
consumed roughly 2300 scf/b (.about.400 Nm.sup.3/m.sup.3). The
conditions resulted in roughly 50 wt % conversion relative to
370.degree. C.
[0140] After processing in the initial sour stage, a fractionator
was used to separate the hydroprocessed effluent into various
fractions. The fractions included light ends, at least one fuels
fraction, a light neutral fraction, a heavy neutral fraction, and a
brightstock fraction. Table 1 shows additional details regarding
the hydroprocessed effluent from the initial sour stage.
TABLE-US-00002 TABLE 1 Hydroprocessed Effluent (Sour Stage) Wt %
(of total Nitrogen content Solvent Product effluent) (wppm) dewaxed
VI H.sub.2S 3.7 NH.sub.3 0.3 C.sub.1 0.4 C.sub.2 0.4 C.sub.3 0.7
C.sub.4 0.9 C.sub.5 1.3 C.sub.6 to 370.degree. C. (fuels 45.6
fraction) Light Neutral 15.5 2 104.2 Heavy Neutral 14.0 2 101.5
Brightstock 18.9 3 104.1
[0141] The light neutral, heavy neutral, and brightstock fractions
from the initial sour hydroprocessing stage were then further
hydroprocessed in the presence of a noble metal hydrocracking
catalyst system (75 wt % of 0.6 wt % Pt on amorphous alumina25 wt %
of 0.6 wt % Pt on alumina bound zeolite Beta), a noble metal
dewaxing catalyst (0.6 wt % Pt on alumina bound ZSM-48), and a
noble metal hydrofinishing catalyst (0.6 wt % Pt on amorphous
alumina). The sweet stage conditions for each fraction included a
pressure of 2500 psig (17.2 MPag), a space velocity (LHSV) of 1.5
hr.sup.-1 across each catalyst or catalyst system, and a hydrogen
treat gas rate of 5000 SCF/b (.about.890 Nm.sup.3/m.sup.3). The
temperatures across each catalyst or catalyst system were selected
separately to achieve desired VI values for each type of feed
fraction.
[0142] For the light neutral feed, the sweet stage temperatures
were selected to achieve roughly 23 wt % conversion relative to
370.degree. C. The average temperature across the first catalyst
system was 530.degree. F. (277.degree. C.), the average temperature
across the second catalyst was 592.degree. F. (311.degree. C.), and
the average temperature across the third catalyst was 428.degree.
F. (220.degree. C.). This produced a light neutral lubricant base
stock in a 77.0 wt % yield relative to the light neutral feed. The
resulting light neutral base stock had a VI of 107 and a kinematic
viscosity at 100.degree. C. of 5.6 cSt. For the heavy neutral feed,
the sweet stage conditions were selected to achieve roughly 7 wt %
conversion relative to 370.degree. C. For heavy neutral processing,
the average temperature across the first catalyst system was
550.degree. F. (288.degree. C.), the average temperature across the
second catalyst was 599.degree. F. (316.degree. C.), and the
average temperature across the third catalyst was 428.degree. F.
(220.degree. C.). This produced a heavy neutral lubricant base
stock in a 92.9 wt % yield relative to the heavy neutral feed. The
resulting heavy neutral base stock had a VI of 104.9 and a
kinematic viscosity at 100.degree. C. of 11.5 cSt. Table 2 provides
additional details regarding the light neutral and heavy neutral
sweet stage blocking products.
TABLE-US-00003 TABLE 2 Light and Heavy Neutral Blocked Sweet Stage
Products Light Neutral Heavy Neutral Product Property VI 107 104.9
Pour Point (.degree. C.) -23 -23 Cloud Point (.degree. C.) -20 -12
KV @40.degree. C. (cSt) 32.17 98.14 KV @100.degree. C. (cSt) 5.56
11.50 Yields H.sub.2 -0.36 -0.39 C.sub.1-C.sub.4 0.27 0.48
C.sub.5-163.degree. C. 1.62 1.56 163.degree. C.-370.degree. C.
21.49 5.43 Lube (LN or HN) 76.98 92.92
[0143] The H.sub.2 "yield" represents the amount of hydrogen
consumed during sweet stage processing. As shown in Table 2, the
viscosity index and pour point of the light neutral and heavy
neutral products are similar. The aromatics content of the lube
fractions was also characterized based on UV absorption. Table 3
shows the UV absorbance values in liters/g-cm for the light neutral
and heavy neutral products.
TABLE-US-00004 TABLE 3 UV Absorbance of Light and Heavy Neutral
Blocked Sweet Stage Products UV wavelength (nm) Light Neutral Heavy
Neutral 226 0.00 0.01 254 0.000 0.003 275 0.000 0.002 302 0.0001
0.0019 310 0.0001 0.0014 325 0.000 0.001 339 0.000 0.0009 400
0.00002 0.0005
[0144] As shown in Table 3, the light neutral product has little or
no UV absorbance at any of the wavelengths investigated. The heavy
neutral product does show some UV absorbance, potentially
indicating the presence of low levels (less than 1.0 wt %) of
aromatic compounds.
[0145] For the brightstock feed, two different sets of sweet stage
temperatures were selected. In a first set of brightstock
processing temperatures, the temperature across the first catalyst
system was 520.degree. F. (271.degree. C.), the temperature across
the second catalyst was 658.degree. F. (348.degree. C.), and the
temperature across the third catalyst was 428.degree. F.
(220.degree. C.). Table 4 shows the products from processing the
blocked brightstock feed at the first set of brightstock processing
temperatures. The resulting brightstock product was bright and
clear upon inspection. It is noted that the resulting products were
fractionated to also generate additional light neutral and heavy
neutral portions. The yields for the light neutral and heavy
neutral products can be combined with the various yields shown in
the bright stock column to arrive at the total yield.
TABLE-US-00005 TABLE 4 Lower Severity Second Stage Brightstock
Processing Light Neutral Heavy Neutral Brightstock Product Property
VI 93.1 92.3 103.3 Pour Point (.degree. C.) -41 -36 -28 Cloud Point
(.degree. C.) <-33 KV @40.degree. C. (cSt) 70.08 190.32 690.5 KV
@100.degree. C. (cSt) 8.62 16.75 41.74 Saybolt +14 Turbidity 5.0
Yields H.sub.2 -0.79 C.sub.1-C.sub.4 6.45 C.sub.5-163.degree. C.
12.86 163.degree. C.-370.degree. C. 11.71 Lube Yields 7.67 18.97
38.75
[0146] As shown in Table 4, the brightstock processing conditions
generated a portion of a light neutral and/or heavy neutral
product. Table 5 shows UV absorption characterization of the light
neutral, heavy neutral, and brightstock products shown in Table 4.
It is noted that the additional light neutral and/or heavy neutral
product had a lower VI than the light neutral or heavy neutral
produced from the block processing of the other lube feed
fractions, but it was otherwise potentially suitable for use as a
separate base stock product. Alternatively, the additional light
neutral and/or heavy neutral products could be recycled to the
light neutral or heavy neutral processing block. This could allow,
for example, the light neutral or heavy neutral processing block to
be operated at a reduced temperature (due to further reduced
nitrogen in the combined feed). Such reduced temperature can be
favorable for further reducing any additional aromatics that might
be present in the recycled product. As still another option, the
additional light neutral and/or heavy neutral product could be
recycled to the initial sour stage for further upgrading, although
this could lead to additional production of fuels as opposed to
lubricant products.
TABLE-US-00006 TABLE 5 UV Absorbance of Lower Severity Brightstock
Feed Sweet Stage Products UV wavelength (nm) Light Neutral Heavy
Neutral Brightstock 226 0.02 0.01 0.01 254 0.07 0.003 0.01 275
0.007 0.002 0.001 302 0.0032 0.0013 0.0007 310 0.0027 0.001 0.0007
325 0.003 0.0007 0.0005 339 0.0034 0.0006 0.0004 400 0.00026
0.00021 0.00017
[0147] In a second set of brightstock processing temperatures, the
temperature across the first catalyst system was 580.degree. F.
(304.degree. C.), the temperature across the second catalyst was
658.degree. F. (348.degree. C.), and the temperature across the
third catalyst was 428.degree. F. (220.degree. C.). Thus, in the
second set of conditions, the primary difference was a higher
temperature for across the hydrocracking catalyst system. Table 6
shows the products from processing the blocked brightstock feed at
the first set of brightstock processing temperatures. The resulting
brightstock product was bright and clear upon inspection. It is
noted that the resulting products were fractionated to also
generate additional light neutral and heavy neutral portions. The
yields for the light neutral and heavy neutral products can be
combined with the various yields shown in the bright stock column
to arrive at the total yield.
TABLE-US-00007 TABLE 6 Higher Severity Second Stage Brightstock
Processing Light Neutral Heavy Neutral Brightstock Product Property
VI 92.9 91.3 100.1 Pour Point (.degree. C.) <-60 <-45 -24
Cloud Point (.degree. C.) <-48 KV @40.degree. C. (cSt) 32.42 119
549 KV @100.degree. C. (cSt) 5.3 12.19 35.7 Saybolt -4 Turbidity
1.3 Yields H.sub.2 -0.82 C.sub.1-C.sub.4 6.41 C.sub.5-163.degree.
C. 14.25 163.degree. C.-370.degree. C. 12.07 Lube Yields 6.19 10.81
51.3
[0148] Table 7 shows UV absorption characterization of the light
neutral, heavy neutral, and brightstock products shown in Table
6.
TABLE-US-00008 TABLE 7 UV Absorbance of Higher Severity Brightstock
Feed Sweet Stage Products UV wavelength (nm) Light Neutral Heavy
Neutral Brightstock 226 0.00 0.01 0.01 254 0.002 0.002 0.003 275
0.001 0.001 0.002 302 0.006 0.0008 0.0011 310 0.0005 0.0006 0.001
325 0.0003 0.0004 0.0007 339 0.0002 0.0003 0.0005 400 0.00008
0.00008 0.00018
Additional Embodiments
[0149] Embodiment 1. A base stock composition comprising a
kinematic viscosity at 100.degree. C. of 30 cSt or more (or 32 cSt
or more), a pour point of -9.degree. C. or less, and a cloud point
that is lower than the pour point.
[0150] Embodiment 2. The composition of Embodiment 1, the
composition further comprising 20 wt % or more naphthenes relative
to a weight of the composition, or 40 wt % or more, or 60 wt % or
more.
[0151] Embodiment 3. The composition of any of the above
embodiments, wherein the composition further comprising a viscosity
index of 80 or more (or 80 to 120); or wherein the composition
further comprises a density at 15.degree. C. of 0.90 g/cm.sup.3 or
less, or 0.89 g/cm.sup.3 or less, or 0.88 g/cm.sup.3 or less (or
0.84 to 0.90); or a combination thereof
[0152] Embodiment 4. The composition of any of the above
embodiments, wherein the pour point is -15.degree. C. or less, or
-20.degree. C. or less; wherein the cloud point is -15.degree. C.
or less, or -20.degree. C. or less; or a combination thereof.
[0153] Embodiment 5. The composition of any of the above
embodiments, wherein the composition further comprises a turbidity
of 5 NTUs or less, or 3 NTUs or less, or 2 NTUs or less; or wherein
the composition is visually free of haze; or a combination
thereof.
[0154] Emboidment 6. A lubricating oil comprising the composition
of any of the above embodiments and a minor amount of one or more
additives chosen from an antiwear additive, a viscosity modifier,
an antioxidant, a detergent, a dispersant, a pour point depressant,
a corrosion inhibitor, a metal deactivator, a seal compatibility
additive, a demulsifying agent, an anti-foam agent, inhibitor, an
anti-rust additive, and combinations thereof, the lubricating oil
optionally comprising at least one of an engine oil, an industrial
lubricating oil, and a marine lubricating oil.
[0155] Embodiment 7. A method for making lubricant base stock,
comprising: performing solvent deasphalting using a C4+ solvent
under effective solvent deasphalting conditions on a feedstock
having a T5 boiling point of at least about 370.degree. C. (or at
least about 400.degree. C., or at least about 450.degree. C., or at
least about 500.degree. C.), the effective solvent deasphalting
conditions producing a yield of deasphalted oil of at least about
50 wt % of the feedstock; hydroprocessing at least a portion of the
deasphalted oil under first effective hydroprocessing conditions
comprising first hydrocracking conditions to form a hydroprocessed
effluent, the at least a portion of the deasphalted oil having an
aromatics content of at least about 50 wt %, the hydroprocessed
effluent comprising a sulfur content of 300 wppm or less, a
nitrogen content of 100 wppm or less, or a combination thereof;
separating the hydroprocessed effluent to form at least a fuels
boiling range fraction, a first fraction having a T5 distillation
point of at least 370.degree. C., and a second fraction having a T5
distillation point of at least 370.degree. C., the second fraction
having a higher kinematic viscosity at 100.degree. C. than the
first fraction; hydroprocessing at least a portion of the first
fraction under second effective hydroprocessing conditions, the
second effective hydroprocessing conditions comprising second
aromatic saturation conditions and second catalytic dewaxing
conditions, to form a first catalytically dewaxed effluent
comprising a 370.degree. C.+ portion having a first kinematic
viscosity at 100.degree. C., the at least a portion of the first
fraction being exposed to the second aromatic saturation conditions
prior to the second catalytic dewaxing conditions, the second
aromatic saturation conditions optionally comprising exposing the
at least a portion of the first fraction to an amorphous aromatic
saturation catalyst; and hydroprocessing at least a portion of the
second fraction under third effective hydroprocessing conditions,
the third effective hydroprocessing conditions comprising third
aromatic saturation conditions and third catalytic dewaxing
conditions, to form a second catalytically dewaxed effluent
comprising a 370.degree. C.+ portion having a second kinematic
viscosity at 100.degree. C. that is greater than the first
kinematic viscosity at 100.degree. C., the at least a portion of
the second fraction being exposed to the third aromatic saturation
conditions prior to the third catalytic dewaxing conditions,
wherein the second effective hydroprocessing conditions are
different from the third effective hydroprocessing conditions.
[0156] Embodiment 8. The method of Embodiment 7, wherein the first
hydroprocessing conditions further comprise first aromatic
saturation conditions, the first aromatic saturation conditions
comprising exposing the at least a portion of the deasphalted oil
to a demetallization catalyst, the at least a portion of the
deasphalted oil being exposed to the demetallization catalyst after
exposing the at least a portion of the deasphalted oil to the
hydrocracking catalyst.
[0157] Embodiment 9. The method of Embodiment 7 or 8, wherein the
second effective hydroprocessing conditions and third effective
hydroprocessing conditions are different based on a difference in
at least one of a hydrocracking pressure, a hydrocracking
temperature, a dewaxing pressure, and a dewaxing temperature.
[0158] Embodiment 10. A method for making lubricant base stock,
comprising: performing solvent deasphalting using a C4+ solvent
under effective solvent deasphalting conditions on a feedstock
having a T5 boiling point of at least about 370.degree. C. (or at
least about 400.degree. C., or at least about 450.degree. C., or at
least about 500.degree. C.), the effective solvent deasphalting
conditions producing a yield of deasphalted oil of at least about
50 wt % of the feedstock; hydroprocessing at least a portion of the
deasphalted oil under first effective hydroprocessing conditions
comprising first hydrocracking conditions to form a hydroprocessed
effluent, the at least a portion of the deasphalted oil having an
aromatics content of at least about 50 wt %; separating the
hydroprocessed effluent to form at least a fuels boiling range
fraction, a first fraction having a T.sub.5 distillation point of
at least 370.degree. C., and a second fraction having a T.sub.5
distillation point of at least 370.degree. C., the second fraction
having a higher kinematic viscosity at 100.degree. C. than the
first fraction; hydroprocessing at least a portion of the first
fraction under second effective hydroprocessing conditions, the
second effective hydroprocessing conditions comprising exposing the
first fraction to a medium pore dewaxing catalyst to form a first
catalytically dewaxed effluent comprising a 370.degree. C.+ portion
having a first kinematic viscosity at 100.degree. C.; and
hydroprocessing at least a portion of the second fraction under
third effective hydroprocessing conditions, the third effective
hydroprocessing conditions comprising exposing the second fraction
to the medium pore dewaxing catalyst to form a second catalytically
dewaxed effluent comprising a 370.degree. C.+ portion having a
second kinematic viscosity at 100.degree. C. that is greater than
the first kinematic viscosity at 100.degree. C., wherein the second
effective hydroprocessing conditions are different from the third
effective hydroprocessing conditions.
[0159] Embodiment 11. The method of Embodiment 10, wherein the
medium pore dewaxing catalyst comprises ZSM-5; wherein the medium
pore dewaxing catalyst comprises 0.05 wt % or less of Group VIII
metals; wherein the at least a portion of the deasphalted oil
comprises a sulfur content of 300 wppm or more; or a combination
thereof
[0160] Embodiment 12. The method of any of Embodiments 7-11,
wherein at least a portion of the first fraction, at least a
portion of the second fraction, at least a portion of the first
catalytically dewaxed effluent, at least a portion of the second
catalytically dewaxed effluent, or a combination thereof is used as
a feed for a steam cracker; or wherein at least a portion of the
second catalytically dewaxed effluent is used as an asphalt blend
component; or a combination thereof.
[0161] Embodiment 13. The method of any of Embodiments 7-12,
wherein separating the hydroprocessed effluent further comprises
forming an additional fraction having a T.sub.5 distillation point
of at least 370.degree. C., the method further comprising:
hydroprocessing at least a portion of the additional fraction under
third effective hydroprocessing conditions, the third effective
hydroprocessing conditions comprising catalytic dewaxing
conditions, to form a third catalytically dewaxed effluent
comprising a 370.degree. C.+ portion having a kinematic viscosity
at 100.degree. C. of 3.5 cSt or more.
[0162] Embodiment 14. The method of any of Embodiments 7-13,
wherein the hydroprocessing at least a portion of the first
fraction and the hydroprocessing at least a portion of the second
fraction comprise block operation of a processing system.
[0163] Embodiment 15. The method of any of Embodiments 7-14,
further comprising recycling at least a portion of the second
catalytically dewaxed effluent as part of the at least a portion of
the deasphalted oil, as part of the at least a portion of the first
fraction, or a combination thereof
[0164] 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 invention
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 invention. 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 invention, including all features which
would be treated as equivalents thereof by those skilled in the art
to which the invention pertains.
[0165] The present invention 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.
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