U.S. patent application number 11/667237 was filed with the patent office on 2008-07-17 for lube basestock with improved low temperature properties.
Invention is credited to Michael Lacey, Robert R. Palmer, Elizabeth Stavens, Lisa Ching Yeh, Lei Zhang.
Application Number | 20080171675 11/667237 |
Document ID | / |
Family ID | 39773123 |
Filed Date | 2008-07-17 |
United States Patent
Application |
20080171675 |
Kind Code |
A1 |
Yeh; Lisa Ching ; et
al. |
July 17, 2008 |
Lube Basestock With Improved Low Temperature Properties
Abstract
This invention relates to basestocks and base oils with improved
low temperature properties and formulated lubricant compositions or
functional fluids created by blending at least one such lube
basestock with at least one component selected from dispersants,
detergents, wear inhibitors, antioxidants, rust inhibitors,
demulsifiers, extreme pressure agents, friction modifiers,
multifunction additives, viscosity index improvers, pour point
depressants, and foam inhibitors. In particular the invention
relates to dewaxed lube basestocks having a Free Carbon Index of
less than 4.3 and an Epsilon Carbon mole % of less than 14%.
Formulated engine oils using such dewaxed basestocks exhibit
improved low temperature properties as may be measured by the Mini
Rotary Viscometer test.
Inventors: |
Yeh; Lisa Ching; (Marlton,
NJ) ; Stavens; Elizabeth; (Seabrook, TX) ;
Palmer; Robert R.; (Bethlehem, PA) ; Lacey;
Michael; (Pearland, TX) ; Zhang; Lei; (Vienna,
VA) |
Correspondence
Address: |
ExxonMobil Research & Engineering Company
P.O. Box 900, 1545 Route 22 East
Annandale
NJ
08801-0900
US
|
Family ID: |
39773123 |
Appl. No.: |
11/667237 |
Filed: |
May 26, 2006 |
PCT Filed: |
May 26, 2006 |
PCT NO: |
PCT/US2005/042119 |
371 Date: |
October 1, 2007 |
Current U.S.
Class: |
508/110 ;
208/18 |
Current CPC
Class: |
C10N 2040/25 20130101;
C10G 2400/10 20130101; C10M 171/02 20130101; C10N 2020/071
20200501; C10N 2020/015 20200501; C10N 2020/02 20130101; C10N
2020/011 20200501; C10N 2020/00 20130101; C10M 101/02 20130101 |
Class at
Publication: |
508/110 ;
208/18 |
International
Class: |
C10M 101/02 20060101
C10M101/02; C10M 105/02 20060101 C10M105/02 |
Claims
1. A dewaxed lube basestock having a Free Carbon Index of less than
4.3 and an Epsilon Carbon mole % of less than 14%.
2. A dewaxed lube basestock having a Free Carbon Index of less than
4.1 and an Epsilon Carbon mole % of less than 13.3%.
3. A dewaxed lube basestock having a Free Carbon Index of from 3.0
to 4.3 and a Epsilon Carbon mole % from 10.0% to 14.0%.
4. A dewaxed lube basestock according to claim 1 wherein the Pour
Point is between -6.degree. C. and -30.degree. C.
5. A dewaxed lube basestock according to claim 2 wherein the Pour
Point is between -6.degree. C. and -30.degree. C.
6. A dewaxed lube basestock according to claim 1 wherein the Pour
Point is between -15.degree. C. and -24.degree. C.
7. A dewaxed lube basestock according to claim 2 wherein the Pour
Point is between -15.degree. C. and -24.degree. C.
8. A dewaxed lube basestock according to claim 1 wherein the
kinematic viscosity at 100.degree. C. is between 3 cSt and 7 cSt,
the Viscosity Index is between 95 and 150, and the Pour Point is
between -6.degree. C. and -30.degree. C.
9. A dewaxed lube basestock according to claim 1 wherein the
kinematic viscosity at 100.degree. C. is between 3 cSt and 7 cSt,
the Viscosity Index is between 100 and 120, and the Pour Point is
between -15.degree. C. and -24.degree. C.
10. A dewaxed lube basestock according to claim 2 wherein the
kinematic viscosity at 100.degree. C. is between 3 cSt and 7 cSt,
the Viscosity Index is between 100 and 120, and the Pour Point is
between -15.degree. C. and -24.degree. C.
11. A dewaxed lube basestock according to claim 1 wherein the
kinematic viscosity at 100.degree. C. is between 4 cSt and 5 cSt,
the Viscosity Index is between 100 and 120, and the Pour Point is
between -15.degree. C. and -24.degree. C.
12. A dewaxed lube basestock having a Free Carbon Index of less
than 4.3 and an Epsilon Carbon mole % of less than 14% prepared by
a process comprising a) solvent dewaxing a lube oil boiling range
feedstream in a solvent dewaxing stage operated under effective
solvent dewaxing conditions thereby producing at least a partially
dewaxed fraction; and b) contacting said partially dewaxed fraction
with a hydrodewaxing catalyst in the presence of a
hydrogen-containing treat gas in a reaction stage operated under
effective hydrodewaxing conditions thereby producing a reaction
product comprising at least a gaseous product and liquid product,
wherein said liquid product comprises a dewaxed lube basestock.
13. A dewaxed lube basestock according to claim 12 wherein said
hydrodewaxing catalyst is selected from ZSM-5, ZSM-22, ZSM-23,
ZSM-35, ZSM-48, ZSM-57, Beta, SSZ-31, SAPO-11, SAPO-31, SAPO-41,
MAPO-11, ECR-42, fluorided alumina, silica-alumina, fluorided
silica alumina, synthetic Ferrierites, Mordenite, Offretite,
Erionite, Chabazite, and mixtures thereof under effective catalytic
dewaxing conditions.
14. A dewaxed lube basestock according to claim 13 wherein said
hydrodewaxing catalyst comprises a zeolite selected from ZSM-48,
ZSM-22 and ZSM-23.
15. A dewaxed lube basestock according to claim 14 wherein said
hydrodewaxing catalyst further comprises at least one metal
hydrogenation component, which is selected from Group VI metals,
Group VIII metals, or mixtures thereof and contains at least one
Group VIII noble metal.
16. A formulated oil comprising: a) a major amount of at least one
dewaxed lube basestock according to claim 4, b) at least one
component selected from dispersants, detergents, wear inhibitors,
antioxidants, rust inhibitors, demulsifiers, extreme pressure
agents, friction modifiers, multifunction additives, viscosity
index improvers, pour point depressants, and foam inhibitors.
17. A formulated oil according to claim 16 wherein the formulated
oil is an engine oil.
18. An engine oil according to claim 17 wherein said engine oil has
a Mini Rotary Viscometer viscosity from about 10,000 cP to about
30,000 cP.
19. An engine oil according to claim 17 wherein said engine oil has
a Mini Rotary Viscometer viscosity from about 10,000 cP to about
25,000 cP.
20. An engine oil according to claim 17 wherein said engine oil has
a Mini Rotary Viscometer viscosity from about 12,000 cP to about
20,000 cP.
21. An engine oil comprising: a) at least 60% by weight of the
total composition of a dewaxed lube basestock having a Free Carbon
Index of from 3.0 to 4.3 and an Epsilon Carbon mole % from 10.0% to
14.0% and wherein the kinematic viscosity at 100.degree. C. is
between 3 cSt and 7 cSt, the Viscosity Index is between 95 and 150,
and the Pour Point is between -6.degree. C. and -30.degree. C. b)
at least one component selected from dispersants, detergents, wear
inhibitors, antioxidants, rust inhibitors, demulsifiers, extreme
pressure agents, friction modifiers, multifunction additives,
viscosity index improvers, pour point depressants, and foam
inhibitors, and wherein the said engine oil has a Mini Rotary
Viscometer viscosity from about 10,000 cP to about 25,000 cP.
22. An engine oil comprising: a) at least 60% by weight of the
total composition of a dewaxed lube basestock having a Free Carbon
Index of from 3.0 to 4.3 and an Epsilon Carbon mole % from 10.0% to
14.0% and wherein the kinematic viscosity at 100.degree. C. is
between 3 cSt and 7 cSt, the Viscosity Index is between 95 and 150,
and the Pour Point is less than -6.degree. C. and wherein said
dewaxed lube basestock is prepared by a process comprising (i)
solvent dewaxing a lube oil boiling range feedstream in a solvent
dewaxing stage operated under effective solvent dewaxing conditions
thereby producing at least a partially dewaxed fraction; and (ii)
contacting said partially dewaxed fraction with a hydrodewaxing
catalyst in the presence of a hydrogen-containing treat gas in a
reaction stage operated under effective hydrodewaxing conditions
thereby producing a reaction product comprising at least a gaseous
product and liquid product, wherein said liquid product comprises a
dewaxed lube basestock. b) at least one component selected from
dispersants, detergents, wear inhibitors, antioxidants, rust
inhibitors, demulsifiers, extreme pressure agents, friction
modifiers, multifunction additives, viscosity index improvers, pour
point depressants, and foam inhibitors, and wherein the said engine
oil has a Mini Rotary Viscometer viscosity from about 10,000 cP to
about 25,000 cP.
23. An engine oil comprising: a) at least 60% by weight of the
total composition of a dewaxed lube basestock having a Free Carbon
Index of from 3.0 to 4.3 and an Epsilon Carbon mole % from 10.0% to
14.0% and wherein the kinematic viscosity at 100.degree. C. is
between 3 cSt and 7 cSt, the Viscosity Index is between 95 and 150,
and the Pour Point is less than -6.degree. C. and wherein said
dewaxed lube basestock is prepared by a process comprising (i)
solvent dewaxing a lube oil boiling range feedstream in a solvent
dewaxing stage operated under effective solvent dewaxing conditions
thereby producing at least a partially dewaxed fraction; and (ii)
contacting said partially dewaxed fraction with a hydrodewaxing
catalyst in the presence of a hydrogen-containing treat gas in a
reaction stage operated under effective hydrodewaxing conditions
thereby producing a reaction product comprising at least a gaseous
product and liquid product, wherein said liquid product comprises a
dewaxed lube basestock. b) at least one component selected from
dispersants, detergents, wear inhibitors, antioxidants, rust
inhibitors, demulsifiers, extreme pressure agents, friction
modifiers, multifunction additives, viscosity index improvers, pour
point depressants, and foam inhibitors, and wherein the said engine
oil has a Mini Rotary Viscometer viscosity from about 10,000 cP to
about 25,000 cP.
24. A method of formulating an engine oil comprising blending a
dewaxed lube basestock as characterized in claim 6 with at least
one component selected from dispersants, detergents, wear
inhibitors, antioxidants, rust inhibitors, demulsifiers, extreme
pressure agents, friction modifiers, multifunction additives,
viscosity index improvers, pour point depressants, and foam
inhibitors.
Description
FIELD OF THE INVENTION
[0001] This invention relates to base stocks and base oils with
improved low temperature properties and formulated lubricant
compositions or functional fluids created by blending at least one
such lube basestock with at least one component selected from
dispersants, detergents, wear inhibitors, antioxidants, rust
inhibitors, demulsifiers, extreme pressure agents, friction
modifiers, multifunction additives, viscosity index improvers, pour
point depressants, and foam inhibitors.
BACKGROUND OF THE INVENTION
[0002] Historically, lubricating oil products for use in many
applications have used additives to impart specific properties to
the finished oils to augment the properties of the basestocks used
to prepare the finished products. With the advent of more demanding
test requirements, the performance requirements for the basestocks
themselves have increased. The American Petroleum Institute (API)
definition of a Group II basestock is one that has a saturates
content of at least 90%, a sulfur content of 0.03 wt. % or less and
a viscosity index (VI) between 80 and 120. Similarly, the API
definition of a Group III basestock is one that has a saturates
content of at least 90%, a sulfur content of 0.03 wt % or less, and
a viscosity index of 120 or greater. Currently, there is a trend in
the lube oil market to use increasing amounts of Group II and III
basestocks to replace the traditionally used Group I basestocks in
order to meet the demand for higher quality finished lubricants and
meet more stringent requirements for improved oxidative stability,
reduced deposits, reduced evaporative emissions, superior low
temperature performance, controlled wear performance, improved fuel
economy, and compatibility with aftertreatment devices.
[0003] While Group II and Group III basestocks provide some of the
attributes desired, further improvements in many properties,
particularly low temperature quality, as well as combinations of
properties, such as superior low temperature fluidity at low
product volatility, continue to challenge the industry. Benefits in
basestock low temperature performance would be beneficial for a
wide range of formulated lubricants and would be particularly
advantageous for passenger vehicle crankcase oils, automatic
transmission fluids, automotive gear oils, hydraulic fluids, and
commercial vehicle crankcase oils.
[0004] Low temperature quality for basestocks and base oils have
historically been controlled using bulk property measurements such
as pour point measured on the basestock, base oils, or formulated
oil composition. However, small amounts of residual wax may not
impact this bulk property measurement and thus, small amounts of
residual wax may go undetected through this analysis. This small
amount of residual wax, however, does negatively impact performance
and can lead to issues such as crankcase oil gelling and loss of
fluidity. Operating an engine in this scenario can lead to engine
damage. Hence, the Mini-Rotary Viscometer (MRV) test was
established to protect engines under cold weather conditions. The
MRV test temperature is set by the Society of Automotive Engineers
(SAE) J-300 Viscosity Classification system for each multigrade
engine oil grade.
[0005] To improve the low temperature performance as measured by
the MRV or other tests sensitive to very small amounts of residual
wax, refineries utilitizing solvent dewaxing can dewax to lower
pour points. While this can be somewhat effective, it may not be as
effective as needed. Catalytic dewaxing, a relatively newer
processing approach, is often more effective than solvent dewaxing,
especially for the light and medium neutral stocks. However, many
existing refineries in operation today utilize solvent dewaxing
only and do not have a reactor available for catalytic dewaxing
which often requires significant quantities of hydrogen provided at
high pressure.
[0006] As the demand for quality formulated lubricant oils
continues to increase, the search for better basestocks produced
from new and different processes, catalysts, and catalyst systems
that exhibit improved quality and performance at high activity and
yield is a continuous, ongoing exercise. Therefore, there is a need
in the lube oil market to provide lube basestocks, that when
formulated into a finished oil, can help to meet the demand for
improved low temperature properties.
SUMMARY OF THE INVENTION
[0007] This invention relates to basestocks with superior low
temperature properties and formulated lubricant compositions or
functional fluids created by blending at least one such lube
basestock with at least one component selected from dispersants,
detergents, wear inhibitors, antioxidants, rust inhibitors,
demulsifiers, extreme pressure agents, friction modifiers,
multifunction additives, viscosity index improvers, pour point
depressants, and foam inhibitors.
[0008] In particular the invention relates to a dewaxed lube
basestock having a Free Carbon Index of less than 4.3 and an
Epsilon Carbon mole % of less than 14%. In other embodiments it
relates to dewaxed lube basestocks having a Free Carbon Index of
less than 4.3 and an Epsilon Carbon mole % of less than 14% or a
dewaxed lube basestock having a Free Carbon Index of less than 4.3
and an Epsilon Carbon mole % of less than 14%, or a dewaxed lube
basestock wherein the Pour Point is between -6.degree. C. and
-30.degree. C.
[0009] In other embodiments the lube basestock is prepared by a
process comprising [0010] a. solvent dewaxing a lube oil boiling
range feedstream in a solvent dewaxing stage operated under
effective solvent dewaxing conditions thereby producing at least a
partially dewaxed fraction; and [0011] b. contacting said partially
dewaxed fraction with a hydrodewaxing catalyst in the presence of a
hydrogen-containing treat gas in a reaction stage operated under
effective hydrodewaxing conditions thereby producing a reaction
product comprising at least a gaseous product and liquid product,
wherein said liquid product comprises a dewaxed lube basestock. In
other embodiments said hydrodewaxing catalyst is selected from
ZSM-5, ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-57, Beta, SSZ-31,
SAPO-11, SAPO-31, SAPO-41, MAPO-11. ECR-42, fluorided alumina,
silica-alumina, fluorided silica alumina, synthetic Ferrierites,
Mordenite, Offretite, Erionite, Chabazite, and mixtures thereof
under effective catalytic dewaxing conditions.
[0012] In yet other embodiments said hydrodewaxing catalyst
comprises a zeolite selected from ZSM-48, ZSM-22 and ZSM-23. In yet
other embodiments said hydrodewaxing catalyst further comprises at
least one metal hydrogenation component, which is selected from
Group VI metals, Group VIII metals, or mixtures thereof and
contains at least one Group VIII noble metal.
[0013] Other embodiments of the invention relate to a formulated
oil comprising: [0014] a. a major amount of at least one dewaxed
lube basestock according to the embodiments described above and,
[0015] b. at least one component selected from dispersants,
detergents, wear inhibitors, antioxidants, rust inhibitors,
demulsifiers, extreme pressure agents, friction modifiers,
multifunction additives, viscosity index improvers, pour point
depressants, and foam inhibitors.
[0016] Other embodiments include an engine oil according to the
above embodiments wherein said engine oil has a Mini Rotary
Viscometer viscosity from about 10,000 cP to about 30,000 cP, or
has a Mini Rotary Viscometer viscosity from about 10,000 cP to
about 25,000 cP, or has a Mini Rotary Viscometer viscosity from
about 12,000 cP to about 20,000 cP.
[0017] In yet other embodiments the invention relates to an engine
oil comprising: [0018] a) at least 60% by weight of the total
composition of a dewaxed lube basestock having a Free Carbon Index
of from 3.0 to 4.3 and an Epsilon Carbon mole % from 10.0% to 14.0%
and wherein the kinematic viscosity at 100.degree. C. is between 3
cSt and 7 cSt, the Viscosity Index is between 95 and 150, and the
Pour Point is between -6.degree. C. and -30.degree. C. [0019] b) at
least one component selected from dispersants, detergents, wear
inhibitors, antioxidants, rust inhibitors, demulsifiers, extreme
pressure agents, friction modifiers, multifunction additives,
viscosity index improvers, pour point depressants, and foam
inhibitors, and wherein the said engine oil has a Mini Rotary
Viscometer viscosity from about 10,000 cP to about 25,000 cP.
[0020] In yet other embodiments the invention relates to an engine
oil comprising: [0021] a) at least 60% by weight of the total
composition of a dewaxed lube basestock having a Free Carbon Index
of from 3.0 to 4.3 and an Epsilon Carbon mole % from 10.0% to 14.0%
and wherein the kinematic viscosity at 100.degree. C. is between 3
cSt and 7 cSt, the Viscosity Index is between 95 and 150, and the
Pour Point is less than -6.degree. C. and wherein said dewaxed lube
basestock is prepared by a process comprising [0022] (i) solvent
dewaxing a lube oil boiling range feedstream in a solvent dewaxing
stage operated under effective solvent dewaxing conditions thereby
producing at least a partially dewaxed fraction; and [0023] (ii)
contacting said partially dewaxed fraction with a hydrodewaxing
catalyst in the presence of a hydrogen-containing treat gas in a
reaction stage operated under effective hydrodewaxing conditions
thereby producing a reaction product comprising at least a gaseous
product and liquid product, wherein said liquid product comprises a
dewaxed lube basestock. [0024] b) at least one component selected
from dispersants, detergents, wear inhibitors, antioxidants, rust
inhibitors, demulsifiers, extreme pressure agents, friction
modifiers, multifunction additives, viscosity index improvers, pour
point depressants, and foam inhibitors, and wherein the said engine
oil has a Mini Rotary Viscometer viscosity from about 10,000 cP to
about 25,000 cP.
[0025] In yet other embodiments the invention relates to an engine
oil comprising: [0026] a) at least 60% by weight of the total
composition of a dewaxed lube basestock having a Free Carbon Index
of from 3.0 to 4.3 and an Epsilon Carbon mole % from 10.0% to 14.0%
and wherein the kinematic viscosity at 100.degree. C. is between 3
cSt and 7 cSt, the Viscosity Index is between 95 and 150, and the
Pour Point is less than -6.degree. C. and wherein said dewaxed lube
basestock is prepared by a process comprising [0027] (i) solvent
dewaxing a lube oil boiling range feedstream in a solvent dewaxing
stage operated under effective solvent dewaxing conditions thereby
producing at least a partially dewaxed fraction; and [0028] (ii)
contacting said partially dewaxed fraction with a hydrodewaxing
catalyst in the presence of a hydrogen-containing treat gas in a
reaction stage operated under effective hydrodewaxing conditions
thereby producing a reaction product comprising at least a gaseous
product and liquid product, wherein said liquid product comprises a
dewaxed lube basestock. [0029] b) at least one component selected
from dispersants, detergents, wear inhibitors, antioxidants, rust
inhibitors, demulsifiers, extreme pressure agents, friction
modifiers, multifunction additives, viscosity index improvers, pour
point depressants, and foam inhibitors, and wherein the said engine
oil has a Mini Rotary Viscometer viscosity from about 10,000 cP to
about 25,000 cP.
[0030] In yet other embodiments the invention relates to a method
of formulating an engine oil comprising blending a dewaxed lube
basestock as characterized in the previously described embodiments
with at least one component selected from dispersants, detergents,
wear inhibitors, antioxidants, rust inhibitors, demulsifiers,
extreme pressure agents, friction modifiers, multifunction
additives, viscosity index improvers, pour point depressants, and
foam inhibitors.
DETAILED DESCRIPTION OF THE INVENTION
[0031] This invention relates to basestocks and base oils with
superior low temperature properties and formulated lubricant
compositions or functional fluids created by blending at least one
such lube basestock with at least one component selected from
dispersants, detergents, wear inhibitors, antioxidants, rust
inhibitors, demulsifiers, extreme pressure agents, friction
modifiers, multifunction additives, viscosity index improvers, pour
point depressants, and foam inhibitors.
[0032] It should be noted that the terms "feedstock" and
"feedstream" can be used interchangeably herein.
[0033] Tests used in describing lubricant compositions of this
invention are: [0034] (a) MRV viscosity measured by Mini-Rotary
Viscometer Test (ASTM D46S4); [0035] (b) CCS viscosity measured by
Cold Cranking Simulator Test (ASTM D5293); [0036] (c) Noack
volatility (or evaporative loss) correlated from Simulated
Distillation by Gas Chromatography using ASTM D2887 or measured
directly by ASTM D5800; [0037] (d) Viscosity index (VI) measured by
ASTM D2270; [0038] (e) Kinematic viscosity measured by ASTM D445
[0039] (f) Pour point (ISL) as measured by ASTM D5950.
[0040] Lube basestocks in the present invention can also be
described as those lube basestocks having a Free Carbon Index (FCI)
of less than 4.3, preferably less than 4.1 or from 3.0 to 4.3,
preferably from 3.0 to 4.1, and an Epsilon Carbon content (mole %)
of less than 14%, preferably less than 13.3. The FCI can be
measured by the method described in, for example, U.S. Pat. No.
6,676,827. The FCI is further explained as follows. The basestock
is analyzed by .sup.13C NMR using a 400 MHz spectrometer. At this
magnetic field strength, all normal paraffins with carbon numbers
greater than C.sub.9 have only five non-equivalent NMR adsorptions
corresponding to the terminal methyl carbons (alpha), as well as
methylenes from the second, third and fourth positions from the
molecular ends (beta, gamma, and delta respectively), and the other
carbon atoms along the backbone which have a common chemical shift
(epsilon). For normal paraffins, the intensities of the alpha,
beta, gamma and delta are equal and the intensity of the epsilon
depends on the length of the molecule. Similarly, the side branches
on the backbone of an iso-paraffin have distinctive chemical
shifts; the presence of a side chain causes a measurable shift at
the tertiary carbon (branch point) on the backbone to which it is
anchored. Further, it also perturbs the chemical sites within three
carbons from this branch point imparting unique chemical shifts
(alpha, beta, and gamma).
[0041] The Free Carbon Index (FCI) is then defined as the product
of the carbon mole percent of epsilon methylenes measured from the
overall carbon species in the .sup.13C NMR spectrum of a basestock
and, the average carbon Number (CN) of the basestock as calculated
from the equation below:
CN = 200 .alpha. - PBu + TMe + TEt + TPr + TBu ##EQU00001##
where the values for .alpha., PBu, TMe, TEt, TPr, and TBu are in
units of carbon mole percent.
[0042] For example, the FCI can be further explained as follows.
Since particular structural types have characteristic spectral
features, the FCI method of data processing provides a description
of the average molecular structure of the normal and branched
paraffins in a sample. Among the figures of merit that result from
this analysis are the average carbon number of the sample (CN), the
number of side chains (NS), and the free carbon index (FCI). The
FCI is defined as the number of carbons that are more than four
carbons away from a chain end or more than three carbons away from
a branch point on a hydrocarbon backbone; these carbons are also
labeled as epsilon, (".epsilon.") in the drawing below. In
practice, FCI represents the product of the CN and the mole
percentage contribution of epsilon to the NMR spectrum.
##STR00001##
[0043] As an example, the above structure illustrates some of the
nomenclature associated with this analysis. For this illustrative
molecule, CN=26, NS=2, and FCI=8. While the above molecule
represents a pure compound, lube basestocks consist of extremely
complex mixtures of molecules. However, since the structural
components such as alpha, beta, gamma, etc. listed above (in
addition to other structural pieces not included above) exhibit
characteristic and repeatable spectral signals, NMR allows for a
statistically averaged structural characterization of the ensemble.
Epsilon and FCI represent the most pertinent features of the NMR
analysis.
[0044] As stated above, the formulated lubricant compositions of
the instant invention also comprise at least one component selected
from dispersants, detergents, wear inhibitors, antioxidants, rust
inhibitors, demulsifiers, extreme pressure agents, friction
modifiers, multifunction additives, viscosity index improvers, pour
point depressants, and foam inhibitors. The at least one component
selected from the above described list, can be any of these
components known. For example, dispersants suitable for use in the
present formulated engine oils can be any dispersants used in
formulated engine oils; detergents suitable for use in the present
lubricant products can be selected from any detergents used in
formulated oils, etc.
[0045] The formulated engine oils of the instant invention can also
be described as possessing a Mini Rotary Viscometer ("MRV")
viscosity less than 30,000 cP, preferably from about 10,000 cP to
about 30,000 cP, more preferably from about 10,000 cP to about
25,000 cP and most preferably from about 12,000 cP to about 20,000
cP.
[0046] The lube oil basestock can be produced by a process
comprising solvent dewaxing a lube oil boiling range feedstream
under conditions effective at producing at least a partially
dewaxed fraction. The partially dewaxed fraction is then contacted
with a catalytic hydrodewaxing catalyst in the presence of hydrogen
containing treat gas in a reaction stage operated under effective
catalytic hydrodewaxing conditions thereby producing a reaction
product comprising at least a gaseous product and liquid product
comprising a lube basestock. A lube oil boiling range feed stream
is first contacted in a first reaction stage with a hydroprocessing
catalyst, in the presence of a hydrogen containing treat gas, under
effective hydroprocessing conditions thereby producing at least a
liquid hydroprocessed lube oil product. The hydroprocessed lube oil
product is then conducted to the solvent dewaxing zone. Also, in
some embodiments of the instant invention, separation stages are
employed to separate gaseous and liquid reaction products, dewaxing
solvent from the dewaxed product, etc.
[0047] As stated above, the formulated oils comprise at least one
lube oil basestock, and the lube oil basestocks suitable for use as
a component in the presently claimed formulated oils are produced
by a specific process. Lube oil boiling range feedstocks suitable
for use in creating the at least one lube oil basestock are
wax-containing feeds that boil in the lubricating oil range. These
lube oil boiling range feedstocks typically having a 10%
distillation point greater than 650.degree. F. (343.degree. C.),
measured by ASTM D 86 or ASTM 2887, and are derived from mineral
sources, synthetic sources, or a mixture of the two. Non-limiting
examples of suitable lubricating oil feedstocks include those
derived from sources such as oils derived from solvent refining
processes such as raffinates, partially solvent dewaxed oils,
deasphalted oils, distillates, vacuum gas oils, coker gas oils,
slack waxes, foots oils and the like, dewaxed oils, Fischer-Tropsch
waxes and GTL materials.
[0048] GTL materials are materials that are derived via one or more
synthesis, combination, transformation, rearrangement, and/or
degradation/deconstructive processes from gaseous carbon-containing
compounds, hydrogen-containing compounds, and/or elements as
feedstocks such as hydrogen, carbon dioxide, carbon monoxide,
water, methane, ethane, ethylene, acetylene, propane, propylene,
propyne, butane, butylenes, and butynes. GTL base stocks and base
oils are GTL materials of lubricating viscosity that are generally
derived from hydrocarbons, for example waxy synthesized
hydrocarbons, that are themselves derived from simpler gaseous
carbon-containing compounds, hydrogen-containing compounds and/or
elements as feedstocks. GTL base stocks and base oils include wax
isomerates, comprising, for example, hydroisomerized or isodewaxed
synthesized waxy hydrocarbons, hydroisomerized or isodewaxed
Fischer-Tropsch (F-T) material (i.e., hydrocarbons, waxy
hydrocarbons, waxes and possible analogous oxygenates), preferably
hydroisomerized or isodewaxed F-T waxy hydrocarbons or
hydroisomerized or isodewaxed F-T waxes, hydroisomerized or
isodewaxed synthesized waxes, or mixtures thereof. The term GTL
base stocks and base oil further encompass the aforesaid base stock
and base oils in combination with other hydroisomerized or
isodewaxed materials comprising for example, hydroisomerized or
isodewaxed mineral/petroleum-derived hydrocarbons, hydroisomerized
or isodewaxed waxy hydrocarbons, or mixtures thereof, derived from
different feed materials including, for example, waxy distillates
such as gas oils, waxy hydrocracked hydrocarbons, lubricating oils,
high pour point polyalphaolefins, foots oil, normal alpha olefin
waxes, slack waxes, deoiled waxes, and microcrystalline waxes.
[0049] These lube oil boiling range feedstocks suitable may also
have high contents of nitrogen- and sulfur-contaminants. Sulfur and
nitrogen contents may be measured by standard ASTM methods D5453
and D4629, respectively.
[0050] The process used to produce lube basestocks suitable for use
in the present formulated oils involves solvent extracting a lube
oil boiling range feedstock in a solvent dewaxing stage operated
under effective solvent dewaxing conditions thereby producing at
least a partially dewaxed fraction. The solvent dewaxing step
typically involves mixing a lube oil boiling range feedstock with a
dewaxing solvent at atmospheric pressure, separating precipitated
wax and recovering solvent for recycling. During the solvent
dewaxing step, the lube oil boiling range feedstock is mixed with
chilled solvent to form an oil-solvent solution and 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. Thus, one
embodiment of the process used to create lube basestocks suitable
for use herein involves separating, by any suitable separation
means, the solvent and partially dewaxed fraction, recovering the
partially dewaxed fraction and conducting the partially dewaxed
fraction to a catalytic hydrodewaxing reaction stage. It should be
noted that because solvent dewaxing typically occurs at atmospheric
pressure, it may be necessary to pressurize the partially dewaxed
fraction prior to the catalytic dewaxing step.
[0051] A particularly suitable solvent dewaxing step 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 lube oil boiling range feedstream-solvent mixture is
agitated during the chilling step to permit substantially
instantaneous mixing of the prechilled solvent with the lube oil
boiling range feedstream. 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./minute,
usually between about 1 to about 5.degree. F./minute. The final
temperature of the lube oil boiling range
feedstream-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.
[0052] Generally, effective solvent dewaxing conditions will
include that amount of solvent that when added to the lube oil
boiling range feedstream will be sufficient to provide a
liquid/solid weight ratio of about 5/1 to about 20/1 at the
dewaxing temperature and a solvent/oil volume ratio between 1.5/1
to 5/1. The solvent dewaxing of the lube oil boiling range
feedstream typically results in a partially dewaxed fraction having
a pour point from about +30.degree. C. to about -20.degree. C. The
benefits observed were seen whether the solvent dewaxing step was
very mild and removed very little wax leaving a higher intermediate
pour point stream or the solvent dewaxing step was more severe and
removed most of the wax leaving a lower intermediate pour point
stream.
[0053] 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. Further
descriptions of solvent dewaxing process useful herein are
disclosed in U.S. Pat. Nos. 3,773,650 and 3,775,288, which are
incorporated herein in their entirety.
[0054] The partially dewaxed fraction from the solvent dewaxing
step is subjected to a catalytic dewaxing step to remove at least a
portion of any wax remaining in the partially dewaxed fraction.
This step is commonly used to further lower the pour point of the
partially dewaxed fraction. The sequence of solvent dewaxing
followed by catalytic dewaxing is designated as trim dewaxing when
the catalytic dewaxing stage removes and isomerizes a relatively
small amount of wax as opposed to the solvent dewaxing step.
[0055] During the catalytic hydrodewaxing step, the partially
dewaxed fraction is contacted with a catalytic hydrodewaxing
catalyst in the presence of a hydrogen containing treat gas in a
reaction stage operated under effective catalytic hydrodewaxing
conditions. Effective catalytic hydrodewaxing conditions as used
herein includes temperatures between about 200.degree. C. to about
350.degree. C., preferably about 250.degree. C. to about
325.degree. C., more preferably 250 to 320.degree. C., pressures
between about 2,860 to about 20,786 kPa (about 400 to about 3,000
psig), preferably about 4,238 to about 17,338 kPa (about 600 to
about 2,500 psig), preferably about 4,238 to about 10,443 kPa
(about 600 to about 1,500 psig) hydrogen treat gas rates of about
89 to about 890 m.sup.3/m.sup.3 (about 500 to about 5,000 SCF
H.sub.2/B), preferably about 107 to about 445 m.sup.3/m.sup.3
(about 600 to about 2,500 SCF H.sub.2/B), and liquid hourly space
velocities ("LHSV") of about 0.1 to about 10 V/v/hr, preferably
about 0.1 to about 5 V/V/hr, more preferably about 0.5 to about 2
V/V/hr. Operating the catalytic hydrodewaxing under these narrow,
less severe, catalytic hydrodewaxing conditions, the catalytic
hydrodewaxing stage reaction stage operates to convert trace
paraffins that impair low temperature properties of the partially
dewaxed fraction at a low yield loss while still maintaining the
key lube basestock properties such as pour point, viscosity,
viscosity index ("VI"), and volatility of the partially dewaxed
fraction resulting from the solvent-dewaxing operation described
herein. Therefore, effective catalytic hydrodewaxing conditions, as
used herein, are to be considered those catalytic hydrodewaxing
conditions as described above that result in a lube basestock
having a VI within about 0 to about 30 points of the partially
dewaxed fraction, a pour point within about 0 to about -50.degree.
C. of the partially dewaxed fraction, and in a yield loss of about
0 to about 20 wt. In all cases the effective catalytic
hydrodewaxing stage follows the solvent dewaxing stage.
[0056] Catalytic hydrodewaxing catalysts suitable for use in the
trim dewaxing step may be either crystalline or amorphous.
Amorphous catalytic hydrodewaxing catalysts include alumina,
fluorided alumina, silica-alumina, fluorided silica-alumina. Such
catalysts are described for example in U.S. Pat. Nos. 4,900,707 and
6,383,366.
[0057] Crystalline materials are molecular sieves that contain at
least one 10 or 12 ring channel and may be based on
aluminosilicates (zeolites) or on aluminophosphates such as
silicoaluminophosphates (SAPOs) and MAPOs. Molecular sieves
suitable for use herein contain at least one 10 or 12 channel.
Examples of such zeolites include ZSM-22, ZSM-23, ZSM-35, ZSM-48,
ZSM-57, ferrierite, ITQ-13, MCM-68 and MCM-71. Examples of
aluminophosphates containing at least one 10 ring channel include
ECR-42. Examples of molecular sieves containing 12 ling channels
include zeolite beta, and MCM-68. Some molecular sieves suitable
for use herein are described in U.S. Pat. Nos. 5,246,566,
5,282,958, 4,975,177, 4,397,827, 4,585,747, 5,075,269 and
4,440,871. MCM-68 is described in U.S. Pat. No. 6,310,265. MCM-71
and ITQ-13 are described in PCT published applications WO 0242207
and WO 0078677. ECR-42 is disclosed in U.S. Pat. No. 6,303,534.
Suitable SAPOs for use herein include SAPO-11, SAPO-31, SAPO-41,
and suitable MAPOs include MAPO-11. SSZ-31 is also a catalyst that
can be effectively used herein.
[0058] It is preferred that the catalytic hydrodewaxing catalyst
used herein be a zeolite. Preferred zeolite catalytic hydrodewaxing
catalysts suitable for use herein include ZSM-48, ZSM-22 and
ZSM-23. The molecular sieves are preferably in the hydrogen
form.
[0059] Preferably, the catalytic hydrodewaxing catalyst selected
would contain a metal hydrogenation component and be bifunctional,
i.e., they are loaded with at least one metal hydrogenation
component, which is selected from Group VI metals, Group VIII
metals, and mixtures thereof. Preferred metals are selected from
Group VIII metals. Especially preferred are Group VIII noble metals
such as Pt, Pd or mixtures thereof. These metals are loaded at the
rate of 0.1 to 30 wt. %, based on catalyst. Catalyst preparation
and metal loading methods are described for example in U.S. Pat.
No. 6,294,077, and include for example ion exchange and
impregnation using decomposable metal salts. Metal dispersion
techniques and catalyst particle size control techniques are
described in U.S. Pat. No. 5,282,958. Catalysts with small particle
size and well-dispersed metal are preferred.
[0060] The molecular sieves are typically composited with binder
materials which are resistant to high temperatures which may be
employed under hydrodewaxing conditions to form a finished
catalytic hydrodewaxing catalyst or may be binderless (self bound).
The binder materials are usually inorganic oxides such as silica,
alumina, silica-aluminas, binary combinations of silicas with other
metal oxides such as titania, magnesia, thoria, zirconia and the
like and tertiary combinations of these oxides such as
silica-alumina-thoria and silica-alumina magnesia. The amount of
molecular sieve in the finished catalytic hydrodewaxing catalyst is
from 10 to 100, preferably 35 to 100 wt. %, based on catalyst. Such
catalysts are formed by methods such spray drying, extrusion and
the like. The catalytic hydrodewaxing catalyst may be used in the
sulfided or unsulfided form, and is preferably in the sulfided form
for metal containing HDW catalyst.
[0061] The catalytic hydrodewaxing reaction stage used to produce
lube basestocks suitable for the present invention can be comprised
of one or more fixed bed reactors or reaction zones each of which
can comprise one or more catalyst beds of the same or different
catalyst. Although other types of catalyst beds can be used, fixed
beds are preferred. Such other types of catalyst beds include
fluidized beds, ebullating beds, slurry beds, and moving beds.
Interstage cooling or heating between reactors, reaction zones, or
between catalyst beds in the same reactor, can be employed. A
portion of any heat generated during catalytic hydrodewaxing can be
recovered. Where this heat recovery option is not available,
conventional cooling may be performed through cooling utilities
such as cooling water or air, or through use of a hydrogen quench
stream. In this maimer, optimum reaction temperatures can be more
easily maintained.
[0062] Hydrogen-containing treat gasses suitable for use in the
catalytic hydrodewaxing reaction stage can be comprised of
substantially pure hydrogen or can be mixtures of other components
typically found in refinery hydrogen streams. However, it is
preferred that the hydrogen-containing treat gas stream contains
little, more preferably no, hydrogen sulfide. The
hydrogen-containing treat gas purity should be at least about 50%
by volume hydrogen, preferably at least about 75% by volume
hydrogen, and more preferably at least about 90% by volume hydrogen
for best results.
[0063] The contacting of the partially dewaxed fraction with the
catalytic hydrodewaxing catalyst results in a reaction product
comprising at least a gaseous product and a liquid product, wherein
the liquid product comprises a lube basestock suitable for use in
the present invention. Thus, the process used to prepare lube
basestocks suitable for use herein involves separating the
catalytic hydrodewaxing stage reaction product into at least the
gaseous product and the liquid product comprising a lube basestock
and recovering the liquid product comprising a lube basestock. The
means by which the catalytic hydrodewaxing stage reaction product
is separated is not critical and may be performed by any means
known to be effective at separating gaseous and liquid reaction
products such as, for example, flash or knock-out drums or
stripping.
[0064] The liquid product, comprising a lube basestock, recovered
from the catalytic hydrodewaxing reaction stage can be
fractionated, by either vacuum or atmospheric distillation, to
provide various lube basestocks that are suitable for use in a
variety of formulated oils.
[0065] A lube oil boiling range feedstream, to be dewaxed according
to the preceding steps, may be treated in a number of processes.
Hydroprocessing refers to processes in which hydrogen reacts with
the lube oil boiling fraction under the influence of a catalyst.
Non-limiting examples of hydroprocessing processes include
hydrocracking; hydrotreating to remove heteroatoms, such as sulfur,
nitrogen, and oxygen; hydrogenation of aromatics;
hydroisomerization and/or catalytic dewaxing; and demetallation of
heavy streams.
[0066] The process used to prepare the lube basestock suitable for
use herein can further comprise solvent extracting a lube oil
boiling range feedstock prior to the solvent dewaxing stage. Thus,
in this example, the feedstream to the solvent dewaxing stage is an
aromatics lean raffinate. A lubricating oil feedstock is extracted
in a solvent extraction zone with an extraction solvent under
conditions effective at producing an aromatics lean raffinate.
[0067] The solvent extraction process selectively dissolves the
aromatic components in an aromatics-rich extract solution while
leaving the more paraffinic components in the aromatics-lean
raffinate solution. 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.
The solvent extraction process, solvent, and process conditions
used herein are not critical to the instant invention and can be
any solvent extraction process known.
[0068] The process used to prepare the one lube basestock suitable
for use herein comprises first solvent extracting a lube oil
boiling range feedstock prior to the first hydroprocessing reactor
stage, as described above, and following this by the solvent
dewaxing stage.
[0069] The above description is directed to preferred embodiments
of the present invention. Those skilled in the art will recognize
that other embodiments that are equally effective could be devised
for carrying out the spirit of this invention.
[0070] The following examples will illustrate the improved
effectiveness of the present invention, but is not meant to limit
the present invention in any fashion.
EXAMPLES
Example 1
Trim Catalytic Hydrodewaxing Using Zeolite Catalysts
[0071] The present invention was illustrated by comparing
formulated engine oils comprising basestocks produced by the
above-described processing sequence, i.e., solvent dewaxing
followed by trim catalytic hydrodewaxing using a zeolite catalyst
with no metal hydrogenation function to others employing only
solvent dewaxing. This data illustrates the benefit of this
invention using a zeolite catalyst to trim hydrodewax over the
traditional approach of solvent dewaxing to lower target pour
point. The properties of the catalysts used, and the amount
employed, in the examples herein are outlined in Table 1 below.
These catalysts included a non-metal HDW catalyst
(H-ZSM-48/Al.sub.2O.sub.3) ("Catalyst B"). Catalyst B was formed
into 1/16'' quadrulobe extrudates that contained 65% ZSM-48
crystals bound with 35% alumina. Catalyst C was formed using
self-bound H-ZSM-5 extrudates.
TABLE-US-00001 TABLE 1 Trim Catalytic Hydrodewaxing Zeolite
Catalyst Properties Catalyst Name Catalyst B Catalyst C H/Pt N/A
N/A Support H-ZSM-48 H-ZSM-5 Binder Al.sub.2O.sub.3 N/A Surface
Area (m.sup.2/g) 239 N/A Alpha 20 47 Catalyst Volume (cc) 5 5
Pre-sulfidation No No
HDW Reactor Preparation and Operating Procedure
[0072] A solvent dewaxed feedstream having the properties outlined
in Table 2 below was separately hydrodewaxed using Catalyst B and
Catalyst C. The trim catalytic hydrodewaxing studies were performed
using a continuous catalyst testing unit composed of a liquid feed
system with an ISCO syringe pump, a fixed-bed tubular reactor with
a three-zone furnace, liquid product collection, and an on-line MTI
GC for gas analysis. 5-10 cc, as outlined in Table 1, of catalyst
was charged in a down-flow 3/8'' stainless steel reactor containing
a 1/8'' thermowell. After the unit was pressure tested, the
catalyst was dried at 300.degree. C. for 2 hours with 250 cc/min
N.sub.2 at ambient pressure. If pre-sulfidation of the catalyst was
required, 2% (vol) H.sub.2S in hydrogen was flowed through the
catalyst bed at 100 sccm for 1 hour. Upon completion of the
catalyst treatment, the reactor was cooled to 150.degree. C., the
unit pressure was set to 1000 psig by adjusting the Mity-Mite
back-pressure regulator and the gas flow was switched from N.sub.2
to H.sub.2. The liquid solvent dewaxed feedstream described in
Table 2 was introduced into the reactor at the desired liquid
hourly space velocity (LHSV). Once the liquid solvent dewaxed
feedstream reached the downstream knockout pot, the reactor
temperature was increased to the target value. A material balance
(MB) was initiated until the unit was lined out for 6 hours. The
total liquid product (TLP) was collected in the MB dropout pot. Gas
samples were analyzed with an on-line HP MTI gas chromatograph (GC)
equipped with both TCD and FID detectors. A series of runs were
performed to understand the catalyst activity/product properties as
function of the process variables, such as LHSV and process
temperature. The TLP product from each balance was cut at
370.degree. C. by batch distillation. The properties of
370+.degree. C. dewaxed oil and wax were analyzed. The 370+.degree.
C. dewaxed oil was then blended as described in the next section
below.
TABLE-US-00002 TABLE 2 Solvent Dewaxed Feedstream Properties
Density, g/cc 0.844 Boiling Range 2% to 98% off, .degree. F.
690-910 Kinematic Viscosity at 40.degree. C., cSt 23.3 Kinematic
Viscosity at 100.degree. C., cSt 4.6 Viscosity Index 114 Pour Point
(ISL), .degree. C. -18 UV Total Aromatics, mmol/kg 18.5 Saybolt
Color >+30 GCD Noack Volatility, wt % 15.2 Sulfur, wppm <10
Nitrogen, wppm <1
Finished Oil Blending and Testing
[0073] The basestock produced by solvent dewaxing followed by
catalytic hydrodewaxing as described above was then blended to make
a 5W-30 engine oil. The above basestock was a lighter viscosity
than required for the finished 5W-30 oil and hence a second
basestock which was somewhat heavier was added to all the blends to
hit a base oil desired viscosity target. A commercial additive
package for GF-3 engine oils was then added to make the formulated
oil. This package consists of a detergent inhibitor package, a
viscosity modifier, and a pour point depressant. The package
utilized and the second basestock were constants in all the blends,
only the light basestock was varied.
[0074] To determine whether zeolite catalysts are effective as trim
catalytic hydrodewaxing catalysts, it is useful to compare their
performance against trim solvent dewaxing samples. These trim
solvent dewaxing samples were processed by using the same feedstock
and further solvent dewaxing to lower target pour points. In this
way, a direct comparison is made between the efficacy of trim
catalytic hydrodewaxing and trim solvent dewaxing. The feedstock
itself which has already been commercially solvent dewaxed is also
blended into the same 5W-30 package to show the benefits of
additional dewaxing whether by solvent or catalytic hydrodewaxing.
The data is shown in Table 3 below.
TABLE-US-00003 TABLE 3 Trim Solvent and HDW Basestock and
Formulated 5W-30 Engine Oil Properties (Catalyst B and C) HDW HDW
Full Solvent Basestock Basestock Physical Property Feed Dewaxing
(Catalyst B) (Catalyst C) Density, g/cc 0.844 0.811 0.811 Kinematic
Viscosity at 40 C., cSt 23.3 23.16 23.34 23.78 Kinematic Viscosity
at 100 C., cSt 4.6 4.60 4.61 4.65 Viscosity Index 114 114.3 113.1
112.8 Pour Point (ISL), deg C. -18 -20 -19 -20 GCD Noack
Volatility, wt % 15.2 15.6 Kinematic Viscosity at 100 C.
(formulated oil), cSt 10.26 10.39 10.35 10.38 CCS (formulated 5W30
engine oil), cP 5790 4600 na na MRV (formulated 5W30 engine oil),
Yield Stress <35 <35 <35 <35 MRV (formulated 5W30
engine oil), cP 36211 33200 29600 31400
[0075] As can be seen from the data, trim solvent dewaxing to about
-20.degree. C. pour point is effective in lowering the MRV
viscosity from 36,211 cP to 33,200 cP, a .about.8% reduction in MRV
viscosity. This shows that it is fairly difficult for a solvent
refinery to dramatically impact the MRV viscosity using only a
small change in target pour point. Large changes in target pour
point, while more effective, also involve much greater yield debits
and chilling costs.
[0076] Using trim catalytic hydrodewaxing with the zeolite
catalysts provides larger benefits. Catalyst C lowered the MRV
viscosity to 31,400 cP, a .about.13% reduction in MRV viscosity.
Catalyst B lowered the MRV to 29,600 cP, a .about.18% reduction in
MRV viscosity. Both of these zeolite catalysts show performance
advantages over the trim solvent dewaxing approach. However, these
advantages were still relatively small and the .sup.13C-NMR Free
Carbon Index and Epsilon Carbon content were negligibly changed (as
shown in Table 4). Decreases in the mole percent of total pendant
groups and the increase in the free carbon index all indicate that
decreased branching, most likely due to cracking, occurred.
TABLE-US-00004 TABLE 4 .sup.13C NMR Data of Trim-HDW Basestock
(Catalyst B) Solvent Dewaxed Trim-HDW Basestock NMR Measurement
Feedstream (Catalyst B) Epsilon Carbons, mole % 13.66 13.64 Total
Pendant Groups, mole % 6.25 6.17 # Side Chains/Molecule 2.3 2.3
Carbon # 36.7 37.7 Free Carbon Index 4.31 4.41
[0077] Because it was sometimes difficult to exactly hit a target
pour point experimentally in our pilot plant reactors, and also to
look at trends, we dewaxed to a range of target pour points. FIG. 1
shows the results over the range of solvent trim dewaxing studied
and the range of trim catalytic hydrodewaxing using Catalyst B and
C. These curves clearly indicate the advantage of trim catalytic
hydrodewaxing over trim solvent dewaxing.
Example 2
Trim Catalytic Hydrodewaxing Using Bifunctional Catalysts
[0078] The present invention was also illustrated by comparing
formulated engine oils comprising basestocks produced by another of
the above-described processing sequences, i.e., solvent dewaxing
followed by trim catalytic hydrodewaxing using a bifunctional
catalyst with a metal hydrogenation function, to others employing
trim catalytic hydrodewaxing using the zeolite catalysts of Example
1. This data illustrates the further benefit of this invention
using a bifunctional catalyst to trim hydrodewax over that shown in
Example 1 of using a zeolite catalyst to trim hydrodewax. The
properties of the catalysts used, and the amount employed, in the
examples herein are outlined in Table 5 below.
TABLE-US-00005 TABLE 5 Trim Catalytic Hydrodewaxing Bifunctional
Catalyst Properties Catalyst Name Catalyst A Pt loading (%) 0.62
H/Pt 1.16 Support ZSM-48 Binder Al.sub.2O.sub.3 Surface Area
(m.sup.2/g) 247 Alpha 24 Catalyst Volume (cc) 10 Pre-sulfidation
Yes
Reactor Preparation and Operating Procedure
[0079] The same feed as shown in Table 2 of Example 1 was used in
this example. The HDW reactor preparation and operating procedure
is also as described above in Example 1 with the following
conditions: T=270-345.degree. C., P=1000 psig, liquid rate=10
cc/hr, H.sub.2 circulation rate=2500 scf/bbl, and LHSV=1 hr.sup.-1.
The 370+.degree. C. dewaxed oil was then collected and blended for
testing.
[0080] The 370.degree. C.+ conversion of the solvent dewaxed
feedstream was seen to increase with increasing reactor
temperatures. A low yield loss (<10%) could be achieved at a
temperature range of 270 to 310.degree. C. For obvious reasons, it
is highly desirable to improve basestock properties while
maximizing lube yield. At mild process conditions (process
temperature @ 290.degree. C.), the trim hydrodewaxed feedstream,
sometimes referred to as a lubricating oil basestock herein, showed
a marginal decrease in pour point from -18.degree. C. to
-19.degree. C., while 370.degree. C.+ product yield loss was only
about 3%, based on the solvent dewaxed feedstream. In addition, the
viscosity index ("VI") and viscosity remained nearly unchanged. An
additional benefit of the present invention is that by using
Catalyst A, a bifunctional catalyst, in the trim HDW mode is the
aromatic saturation capability of the catalyst. The aromatics
content of the trim HDW product is essentially zero. High saturate
content, i.e., saturated aromatics, in the lube product provides
better oxidation stability and increases the value of the lube oil
basestock. Table 6 summarizes the physical properties of the lube
fraction of the product with the highest 370.degree. C.+ yield.
TABLE-US-00006 TABLE 6 Trim HDW Basestock Properties (Catalyst A)
Trim-HDW Basestock Physical Property Feed (Catalyst A) 370.degree.
C.+ Yield, % on SDW feed 97.5 94.6 Kinematic Viscosity at
40.degree. C., cSt 23.3 23.7 Kinematic Viscosity at 100.degree. C.,
cSt 4.6 4.7 Viscosity Index 114 113 Pour Point (ISL), .degree. C.
-18 -19 UV Total Aromatics, mmol/kg 18.5 0 Saybolt Color >+30
>+30 GCD Noack Volatility, wt % 15.2 15.3
Finished Oil Blending and Testing
[0081] The basestock produced by solvent dewaxing followed by
catalytic hydrodewaxing as described above was then blended to make
a 5W-30 engine oil. The above basestock was a lighter viscosity
than required for the finished 5W-30 oil and hence a second
basestock which was somewhat heavier was added to all the blends to
hit a base oil desired viscosity target. A commercial additive
package for GF-3 engine oils was then added to make the formulated
oil. This package consists of a detergent inhibitor package, a
viscosity modifier, and a pour point depressant. The package
utilized and the second basestock were constants in all the blends,
only the light basestock was varied.
[0082] To assess the performance of bifunctional catalysts, they
were compared to other trim samples including the trim catalytic
hydrodewaxing samples of Example 1. The feedstock itself which has
already been commercially solvent dewaxed is also blended into the
same 5W-30 package to show the benefits of additional trim
dewaxing. The data generated using the bifunctional Catalyst A is
shown in Table 7 below. The pilot plant run was done twice; hence
the first two columns used a basestock made in the first run and
the third column used a basestock made in the second run.
TABLE-US-00007 TABLE 7 Trim HDW Basestock and Formulated 5W-30
Engine Oil Properties (Catalyst A) HDW (Catalyst HDW (Catalyst HDW
(Catalyst Physical Property Feed A) A) A) Density, g/cc 0.844 0.810
0.810 Kinematic Viscosity at 40 C., cSt 23.3 23.65 23.65 23.73
Kinematic Viscosity at 100 C., cSt 4.6 4.64 4.64 4.66 Viscosity
Index 114 113.1 113.1 113.6 Pour Point (ISL), deg C. -18 -19 -19
-20 GCD Noack Volatility, wt % 15.2 Kinematic Viscosity at 100 C.
(formulated oil), cSt 10.26 10.33 10.36 10.12 CCS (formulated 5W30
engine oil), cP 5790 5180 MRV (formulated 5W30 engine oil), Yield
Stress <35 <35 <35 <35 MRV (formulated 5W30 engine
oil), cP 36211 19338 19536 19997
[0083] As can be seen from the data, trim catalytic hydrodewaxing
to about -20.degree. C. pour point is surprisingly effective in
lowering the MRV viscosity from 36,211 cP to an average value of
19,624 cP, a 46% reduction in MRV viscosity. This level of MRV
viscosity reduction under such mild catalytic hydrodewaxing
condition and with only small changes in basestock bulk properties
was much greater than expected. As summarized in Table 6, minimal
changes to basestock physical properties (viscosity, VI, pour
point, volatility) were observed. Table 8 highlights the key
.sup.13C NMR results of the feed versus trim HDW basestock.
.sup.13C NMR was used to show that mild trim catalytic
hydrodewaxing isomerizes the trace paraffins that impair the low
temperature, low-shear properties of solvent-dewaxed basestocks to
provide exceptional improvements to formulated engine oil cold flow
properties. A substantial reduction to the NMR Free Carbon Index
from 4.31 to 4.02 was seen. Also a significant reduction to the NMR
Epsilon Carbon content from 13.66 mole % to 13.04 mole % was
obtained. This confirms that a significant change to the molecular
structure of the lube molecules was achieved without significant
alteration to standard basestock physical properties.
TABLE-US-00008 TABLE 8 .sup.13C NMR Data of Trim-Hydrodewaxed
Basestock(Catalyst A) Trim-HDW Basestock NMR Measurement Feed
(Catalyst A) Epsilon Carbons, mole % 13.66 13.04 Total Pendant
Groups, mole % 6.25 6.58 Pendant Methyl Groups, mole % 5.00 5.30 #
Side Chains/Molecule 2.3 2.4 Carbon # 36.7 36.5 Free Carbon Index
4.31 4.02
[0084] This 46% decrease in MRV and 11% decrease in CCS were
obtained with less than 3% yield loss in mild trim-HDW with
Catalyst A. As noted above, the aromatic saturation benefit of
using the Catalyst A in a trim HDW mode is clearly reflected by the
negligible aromatics content of the trim hydrodewaxed product. The
MRV improvement and yield loss associated with the trim HDW over
Catalyst A are superior to the improvements observed in Example 1
where Catalyst B and C were employed in the trim HDW setup as
demonstrated by the 46% MRV improvement with <3% yield loss.
This was achieved through an effective molecular re-arrangement
that was achieved with Catalyst A but not with Catalyst B and C as
evidenced by the NMR measurements. This is discussed further
below.
[0085] Increases in the mole percent of total pendant groups, mole
percent of pendant methyl groups, and number of side chains and the
decrease observed in the mole percent of epsilon carbons and free
carbon index all indicate that increased branchiness of lube
molecules, likely due to isomerization, has occurred. No
significant changes in carbon number (CN) were observed. The trends
shown in Table 8 indicate that isomerization is likely the key
mechanism behind the extensive improvement observed in engine oil
low temperature properties using Catalyst A in a mild trim
catalytic hydrodewaxing. Thus, overall, the trends in Table 4 are
quite opposite to the trends observed in Table 8. The trends shown
in Table 4 indicate that cracking is the likely the key mechanism
behind the 17% improvement in MRV observed in engine oil low
temperature properties using the Catalyst B in a mild trim
catalytic hydrodewaxing mode. Cracking is not as effective in
altering the molecular structure as isomerization as evidenced by
the NMR data. Cracking is also not as effective in improving the
low temperature quality as shown by the MRV data discussed
above.
[0086] Because it was sometimes difficult to exactly hit a target
pour point experimentally in our pilot plant reactors, and also to
look at trends, we dewaxed to a range of target pour points. FIG. 2
shows the results over the range of trim catalytic hydrodewaxing
using Catalysts A, B, C, D, and E. These curves clearly indicate
the advantage of trim catalytic hydrodewaxing using a bifunctional
catalyst such as Catalyst A over trim catalytic hydrodewaxing using
a zeolite catalyst such as Catalyst B and C. This can be most
readily seen by looking at the MRV viscosity obtained at similar
pour points, especially those pour points closer to the feed such
as around -20.degree. C.
[0087] This example illustrated the improvement in low-temperature
properties achievable using trim catalytic hydrodewaxing of a
solvent-dewaxed feedstream at mild conditions with Catalyst A. This
example also demonstrates that although trim HDW using Catalyst B
and C improved the low temperature property of the solvent dewaxed
feedstream, the low temperature property improvement demonstrated
by the present invention employing Catalyst A were superior to
those obtained with Catalyst B.
[0088] .sup.13C NMR was used to show that mild trim catalytic
hydrodewaxing isomerizes the trace paraffins that impair the low
temperature, low-shear properties of solvent-dewaxed basestocks to
provide exceptional improvements to formulated engine oil cold flow
properties. Table 9 highlights the key .sup.13C NMR results of the
feed versus trim HDW basestock.
TABLE-US-00009 TABLE 9 .sup.13C NMR Data of Trim-Hydrodewaxed
Basestock(Catalyst A) Trim-HDW Basestock NMR Measurement Feed
(Catalyst A) Epsilon Carbons, mole % 13.66 13.04 Total Pendant
Groups, mole % 6.25 6.58 Pendant Methyl Groups, mole % 5.00 5.30 #
Side Chains/Molecule 2.3 2.4 Carbon # 36.7 36.5 Free Carbon Index
4.31 4.02
[0089] Increases in the mole percent of total pendant groups, mole
percent of pendant methyl groups, and number of side chains and the
decrease observed in the mole percent of epsilon carbons and free
carbon index all indicate that increased branchiness of lube
molecules, likely due to isomerization, has occurred. No
significant changes in carbon number (CN) were observed. The trends
shown in Table 6 indicate that isomerization is likely the key
mechanism behind the extensive improvement observed in engine oil
low temperature properties using Catalyst A in a mild trim
catalytic hydrodewaxing. Thus, overall, the trends in Table 4 are
quite opposite to the trends observed in Table 6. The trends shown
in Table 4 indicate that cracking is the likely the key mechanism
behind the 17% improvement in MRV viscosity observed in engine oil
low temperature properties using the Catalyst B in a mild trim
catalytic hydrodewaxing mode. Cracking is not as effective in
altering the molecular structure as isomerization as evidenced by
the NMR data. Cracking is also not as effective in improving the
low temperature quality as shown by the MRV viscosity data
discussed above.
Example 3
Comparative Example of HDW Followed by SDW
[0090] To further explore the potential for improving the low
temperature quality of a finished lubricant, the study was extended
beyond trim dewaxing. trim dewaxing utilizes a solvent dewaxing
process to dewax a waxy feed so that the majority of wax is removed
in this first process. The second step of trim dewaxing is then
done on the nearly dewaxed feed and only removes or isomerizes
small amounts of residual wax. To identify whether the balance of
wax removal between the first process and second process could be
modified, we extended the study to samples which had only been
partially or mildly dewaxed in the first step leaving more residual
wax for the second step to handle.
[0091] We also wanted to determine of catalytic hydrodewaxing first
followed by solvent dewaxing as the second process would be
effective. The degree of catalytic hydrodewaxing in the first stage
was varied to also look at the impact of catalytic hydrodewaxing
severity and solvent dewaxing severity. That is the subject of this
third example. The catalytic hydrodewaxing catalyst used was
Catalyst A.
[0092] The HDW reactor preparation and operating procedure is same
as described above in Example 1.
[0093] SDW Lab Procedure
[0094] The lab solvent dewaxings were conducted using a single
stage batch filtration with the large Buchner funnel apparatus.
This apparatus uses a 24-cm filtration area and has up to a 1.5
gallon oil/wax/solvent slurry capacity. The solvent was a mixture
of methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK).
[0095] As the filtration proceeds, the predominately wax component
is left on the surface of the filtration media, with the filtrate
(oil and solvent) passing through the filter into a collection
flask. These two products are then stripped of their respective
solvents using a rotary vacuum stripper to complete the filtration
process. The DWO and wax were further analyzed to determine their
individual physical properties.
[0096] The feed used in this case was a waxy light feedstream from
the refinery and was a slightly lower viscosity grade than in
Example 1 and 2.
TABLE-US-00010 TABLE 10 HDW Followed by SDW Basestock and
Formulated 5W-30 Engine Oil Properties Using Various Degrees of HDW
to SDW HDW to 30, HDW to 13, HDW to -7, Physical Property Base Case
SDW to -18 SDW to -19 SDW to -20 Density, g/cc 0.844 Kinematic
Viscosity at 40 C., cSt 23.3 18.91 18.462 17.82 Kinematic Viscosity
at 100 C., cSt 4.6 4.09 4.04 3.97 Viscosity Index 114 117.1
118.210086 120.6 Pour Point (ISL), deg C. -18 -18 -19 -20 GCD Noack
Volatility, wt % 15.2 Kinematic Viscosity at 100 C. (formulated
oil), cSt 10.26 10.28 10.27 10.26 CCS (formulated 5W30 engine oil),
cP 5790 6483 5227 MRV (formulated 5W30 engine oil), Yield Stress
<35 <175 <175 <175 MRV (formulated 5W30 engine oil), cP
36211 103488 102578 92649
[0097] In this comparative example, the formulated oil MRV
viscosity values measured were undesirable (Shown in Table 10). The
base case full solvent dewaxed sample to -18.degree. C. pour point
gave a 5W-30 MRV viscosity of 36,211 cP with No Yield Stress
(<35 Pa). The mildest HDW example was HDW to +30.degree. C.
followed by SDW to -18.degree. C., which is a very similar pour
point to the base case. The 5W-30 MRV viscosity was 103,488 cP,
much higher than base case, and a Yield Stress of <175 Pa was
found. Thus this formulated oil fails the MRV viscosity
specifications on both apparent viscosity and yield stress. The
intermediate HDW example was HDW to +13.degree. C. followed by SDW
to -19.degree. C., which is a very similar pour point to the base
case. The 5W-30 MRV viscosity was 102,578 cP, again much higher
than the base case, and a yield stress of <175 Pa was found.
Thus this formulated oil again fails the MRV viscosity
specifications on both apparent viscosity and yield stress. The
most severe HDW example was HDW to -7.degree. C. followed by SDW to
-20.degree. C., which is a very similar pour point to the base
case. The 5W-30 MRV apparent viscosity was 92,649 cP, again much
higher than the base case, and a yield stress of <175 Pa was
found. Thus this formulated oil again fails the MRV viscosity
specifications on both apparent viscosity and yield stress.
[0098] In all three cases, the NMR results help to explain the MRV
viscosity results seen. The Free Carbon Index has risen to 4.85 to
5.02% and the Epsilon Carbon content has increased to 15.35 mole %
to 16.30 mole %. This is a comparative example that shows that when
the NMR Free Carbon Index and Epsilon Carbon contents exceed 4.3
and 14%, respectively, the low temperature quality of the finished
oil as demonstrated by the MRV viscosity deteriorates.
[0099] Thus, it is shown that HDW followed by SDW to an acceptable
pour point is unable to achieve acceptable finished oil low
temperature quality. Even when the first HDW step is done to within
about 11.degree. C. of the desired target, it is still not
sufficient to generate good quality product.
[0100] To look at trends going to lower pour points, the final SDW
step was taken to lower target pour points and the data is plotted
in FIG. 3 below. It can be seen that even at lower final pour
points of -23 and -24.degree. C., HDW followed by SDW is still not
competitive with full SDW performance.
Example 4
SDW Followed by HDW
[0101] To further explore the potential for improving the low
temperature quality of a finished lubricant, the study was extended
beyond trim dewaxing. trim dewaxing utilizes a solvent dewaxing
process to dewax a waxy feed so that the majority of wax is removed
in this first process. The second step of trim dewaxing is then
done on the nearly dewaxed feed and only removes or isomerizes
small amounts of residual wax. To identify whether the balance of
wax removal between the first process and second process could be
modified, we extended the study to samples which had only been
partially or mildly dewaxed in the first step leaving more residual
wax for the second step to handle.
[0102] In this example, the first step is a Solvent Dewaxing
Process to various intermediate pour points followed by Catalytic
hydrodewaxing using Catalyst A to the final target pour points.
[0103] The feed used in this case was a waxy light feedstream from
a refinery and was a slightly lower viscosity grade than in Example
1 and 2 and the same feedstream as used in Example 3.
TABLE-US-00011 TABLE 11 SDW Followed by HDW Basestock and
Formulated 5W-30 Engine Oil Properties Using Various Degrees of SDW
to HDW SDW to 10, SDW to -2, Physical Property Base Case HDW to -21
HDW to -19 Density, g/cc 0.844 0.801 0.803 Kinematic Viscosity at
40 C., cSt 23.3 18.28 18.88 Kinematic Viscosity at 100 C., cSt 4.6
4.01 4.09 Viscosity Index 114 117.5 117.5 Pour Point (ISL), deg C.
-18 -21 -19 GCD Noack Volatility, wt % 15.2 Kinematic Viscosity at
100 C. (formulated oil), cSt 10.26 10.26 10.28 CCS (formulated 5W30
engine oil), cP 5790 4950 5126 MRV (formulated 5W30 engine oil),
Yield Stress <35 <35 <35 MRV (formulated 5W30 engine oil),
cP 36211 17873 22826
[0104] In this example, the formulated oil MRV viscosity values
were much better than the base case (shown in Table 11). The base
case full solvent dewaxed sample to -18.degree. C. pour point gave
a 5W-30 MRV viscosity of 36,211 cP with no yield stress (<35
Pa). The milder SDW example was SDW to +10.degree. C. followed by
SDW to -21.degree. C., which is a very similar pour point to the
base case. The 5W-30 MRV viscosity was 17,873 cP, which is 51%
lower than the base case with no Yield Stress (<35 Pa). The more
intermediate SDW example was SDW to -2.degree. C. followed by HDW
to -19.degree. C., which is a very similar pour point to the base
case. The 5W-30 MRV viscosity was 22,826 cP, which is 37% lower
than the base case, and no Yield Stress (<35 Pa) was found. The
most severe SDW example is the trim cases discussed in Examples 1
and 2. Example 2 also used Catalyst A and the 5W-30 MRV viscosity
average value was 19,624 cP which was a 46% reduction and the
benefit magnitude is very similar to what is shown here.
[0105] Again, in all three cases, the NMR results help to explain
the MRV viscosity results seen. The Free Carbon Index has dropped
to 4.09 to 4.29% and the Epsilon Carbon content has decreased to
13.67 mole % to 13.72 mole %. This shows that when the NMR Free
Carbon Index and Epsilon Carbon contents decrease below 4.3 and
14%, respectively, the low temperature quality of the finished oil
as demonstrated by the MRV viscosity improves.
[0106] Thus, it is shown that SDW followed by HDW to an acceptable
pour point is a surprisingly effective means to achieve acceptable
finished oil low temperature quality. This large benefit is seen
independent of the relative amount of SDW to HDW. It seems critical
that the final step be HDW but whether the SDW is run quite mild to
higher pour points are run more severely to lower pour points does
not impact how effective this processing approach is in impacting
finished oil low temperature quality.
[0107] To look at trends going to lower pour points, the final HDW
step was taken to lower target pour points and the data is plotted
in FIG. 4 below. It can be seen that as the final pour point is
lowered, the benefits continue until a final MRV viscosity of
10,000 -15,000 cP is reached.
* * * * *