U.S. patent application number 11/285630 was filed with the patent office on 2006-04-13 for process for improving the lubricating properties of base oils using a fischer-tropsch derived bottoms.
This patent application is currently assigned to Chevron U.S.A. Inc.. Invention is credited to Stephen J. Miller.
Application Number | 20060076267 11/285630 |
Document ID | / |
Family ID | 33518231 |
Filed Date | 2006-04-13 |
United States Patent
Application |
20060076267 |
Kind Code |
A1 |
Miller; Stephen J. |
April 13, 2006 |
Process for improving the lubricating properties of base oils using
a fischer-tropsch derived bottoms
Abstract
A method for improving the lubricating properties of a
distillate base oil characterized by a pour point of 0 degrees C.
or less and a boiling range having the 10 percent point falling
between about 625 degrees F. and about 790 degrees F. and the 90
percent point falling between about 725 degrees F. and about 950
degrees F., the method comprises blending with said distillate base
oil a sufficient amount of a pour point depressing base oil
blending component to reduce the pour point of the resulting base
oil blend at least 3 degrees C. below the pour point of the
distillate base oil, wherein the pour point depressing base oil
blending component is an isomerized Fischer-Tropsch derived bottoms
product having a pour point that is at least 3 degrees C. higher
than the pour point of the distillate base oil.
Inventors: |
Miller; Stephen J.; (San
Francisco, CA) |
Correspondence
Address: |
CHEVRON TEXACO CORPORATION
P.O. BOX 6006
SAN RAMON
CA
94583-0806
US
|
Assignee: |
Chevron U.S.A. Inc.
|
Family ID: |
33518231 |
Appl. No.: |
11/285630 |
Filed: |
November 21, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10704031 |
Nov 7, 2003 |
|
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11285630 |
Nov 21, 2005 |
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Current U.S.
Class: |
208/27 ;
208/950 |
Current CPC
Class: |
C10G 2300/1062 20130101;
C10G 2300/301 20130101; C10M 2205/173 20130101; Y10S 208/95
20130101; C10M 2203/1006 20130101; C10G 2300/1022 20130101; C10M
111/04 20130101; C10M 111/00 20130101; C10M 169/04 20130101; C10G
2400/10 20130101; C10N 2020/071 20200501; C10N 2020/02 20130101;
C10G 2300/304 20130101; C10M 2205/17 20130101; C10N 2070/00
20130101; C10N 2030/02 20130101; C10N 2020/04 20130101; C10G
2300/302 20130101 |
Class at
Publication: |
208/027 ;
208/950 |
International
Class: |
C10G 73/38 20060101
C10G073/38 |
Claims
1-42. (canceled)
43. A process for preparing a pour point depressing base oil
blending component suitable for lowering the pour point of a base
oils which comprises (a) isomerizing a Fischer-Tropsch derived
product and (b) recovering from the isomerized Fischer-Tropsch
derived product a Fischer-Tropsch derived bottoms having an average
molecular weight between about 600 and about 1100 and an average
degree of branching in the molecules between about 6.5 and about 10
alkyl branches per 100 carbon atoms.
44. The process of claim 43 wherein the Fischer-Tropsch derived
bottoms recovered in step (b) has an average molecular weight
between about 700 and about 1000.
45. The process of claim 43 wherein the Fischer-Tropsch derived
bottoms recovered in step (b) has a kinematic viscosity at 100
degrees C. within the range of from about 8 and about 22 cSt.
46. The process of claim 43 wherein the Fischer-Tropsch derived
bottoms recovered in step (b) has a pour point of between about -9
degrees C. and about 20 degrees C.
47. The process of claim 43 wherein the Fischer-Tropsch derived
bottoms recovered in step (b) has a boiling range in which the 10
percent point falls between about 850 degrees F. and about 1050
degrees F.
48. The process of claim 43 including the additional step of
solvent dewaxing the Fischer-Tropsch derived bottoms and separating
a waxy product having improved pour point depressing properties as
compared to the Fischer-Tropsch derived bottoms.
49-57. (canceled)
Description
FIELD OF THE INVENTION
[0001] This invention is directed to a process for improving the
lubricating properties of a distillate base oil by blending it with
a pour point depressing base oil blending component prepared from
an isomerized Fischer-Tropsch derived bottoms. The invention also
includes the composition of the pour point depressing base oil
blending component and of the base oil blend.
BACKGROUND OF THE INVENTION
[0002] Finished lubricants used for automobiles, diesel engines,
axles, transmissions, and industrial applications consist of two
general components, a lubricating base oil and additives.
Lubricating base oil is the major constituent in these finished
lubricants and contributes significantly to the properties of the
finished lubricant. In general, a few lubricating base oils are
used to manufacture a wide variety of finished lubricants by
varying the mixtures of individual lubricating base oils and
individual additives.
[0003] Numerous governing organizations, including original
equipment manufacturers (OEM's), the American Petroleum Institute
(API), Association des Consructeurs d'Automobiles (ACEA), the
American Society of Testing and Materials (ASTM), and the Society
of Automotive Engineers (SAE), among others, define the
specifications for lubricating base oils and finished lubricants.
Increasingly, the specifications for finished lubricants are
calling for products with excellent low temperature properties,
high oxidation stability, and low volatility. Currently, only a
small fraction of the base oils manufactured today are able to meet
these demanding specifications.
[0004] Lubricating base oils are base oils having a viscosity of
about 3 cSt or greater at 100 degrees C., preferably about 4 cSt or
greater at 100 degrees C.; a pour point of about 9 degrees C. or
less, preferably about -15 degrees C. or less; and a VI (viscosity
index) that is usually about 90 or greater, preferably about 100 or
greater. In general, lubricating base oils should have a Noack
volatility no greater than current conventional Group I or Group II
light neutral oils. Group II base oils are defined as having a
sulfur content of equal to or less than 300 ppm, saturates equal to
90 percent or greater, and a VI between 80 and 120. A Group II base
oil having a VI between about 110 and 120 is referred to in this
disclosure as a Group II plus base oil. Group III base oils are
defined as having a sulfur content of equal to or less than 300
ppm, saturates equal to 90 percent or greater, and a VI of greater
than 120. It would be advantageous to be able to boost the VI of a
Group II base oil into the Group II plus and the Group III base oil
range. The present invention makes it possible to lower pour point
and raise VI. Depending upon the amount of pour point depressing
base oil blending component added to the base oil blend, the Noack
volatility may also be lowered and the viscosity of the base oil
may be raised.
[0005] Base oil refers to a hydrocarbon product having the above
properties prior to the addition of additives. That is, the term
"base oil" generally refers to a petroleum or syncrude fraction
recovered from the fractionation operation. "Additives" are
chemicals which are added to improve certain properties in the
finished lubricant so that it meets relevant specifications.
Conventional pour point additives are expensive and add to the cost
of the finished lubricant. Some additives also present solubility
problems and require their use along with a solvent. Consequently,
it is desirable to use the minimum amount of an additive necessary
to produce an on specification lubricant.
[0006] Pour point which is an important property of base oils
intended for blending into finished lubricants is the lowest
temperature at which movement of the base oil is observed. In order
to meet the relevant pour point specification for a finished
lubricant, it is often necessary to lower the pour point of the
base oil by the addition of an additive. Conventional additives
which have been used to lower the pour point of base oils are
referred to as pour point depressants (PPDs) and typically are
polymers with pendant hydrocarbon chains that interact with the
paraffins in the base by inhibiting the formation of large wax
crystal lattices. Examples of pour point depressants known to the
art include ethylene-vinyl-acetate copolymers, vinyl-acetate olefin
copolymers, alkyl-esters of styrene-maleic-anhydride copolymers,
alkyl-esters of unsaturated-carboxylic acids, polyalkylacrylates,
polyalklymethacrylates, alkyl phenols, and alpha-olefin copolymers.
Many of the known pour point depressants are solid at ambient
temperature and must be diluted drastically with solvent prior to
use. See Factors Affecting Performance of Crude Oil Wax-Control
Additives by J. S. Manka and K. L. Ziegler, World Oil, June 2001,
pages 75-81. Pour point depressants taught in the literature have a
wax-like paraffinic part, which co-crystallizes with the
wax-forming components in the oil, and a polar part which hinders
crystal growth. The pour point depressing base oil blending
component employed in the present invention differs from pour point
depressants known from the prior art in being essentially both
aromatic-free and polar-free. One of the advantages of the present
invention is that the pour point depressing base oil blending
component of the present invention is not an additive in the
conventional sense. The pour point depressing base oil blending
component used in the invention is only a high boiling syncrude
fraction which has been isomerized under controlled conditions to
give a specified degree of alkyl branching in the molecule.
Therefore, it does not lend itself to problems which have been
associated with the use of conventional additives.
[0007] Syncrude prepared from the Fischer-Tropsch process comprises
a mixture of various solid, liquid, and gaseous hydrocarbons. Those
Fischer-Tropsch products which boil within the range of lubricating
base oil contain a high proportion of wax which makes them ideal
candidates for processing into lubricating base oil stocks.
Accordingly, the hydrocarbon products recovered from the
Fischer-Tropsch process have been proposed as feedstocks for
preparing high quality lubricating base oils. When the
Fischer-Tropsch waxes are converted into Fischer-Tropsch base oils
by various processes, such as by hydroprocessing and distillation,
the base oils produced fall into different narrow-cut viscosity
ranges. Those Fischer-Tropsch cuts which have properties which make
them suitable for preparing lubricating base oils are particularly
advantageous for blending with marginal quality conventional base
oils or Fischer-Tropsch derived base oils due to their low
volatility, low sulfur content, and excellent cold flow properties.
The bottoms that remains after recovering the lubricating base oil
cuts from the vacuum column is generally unsuitable for use as a
lubricating base oil itself and is usually recycled to a
hydrocracking unit for conversion to lower molecular weight
products. Applicant has found that the high molecular weight
hydrocarbons associated with the bottoms when properly processed
are particularly useful for improving the lubricating properties of
base oils, either conventionally derived or Fischer-Tropsch
derived.
[0008] As used in this disclosure the phrase "Fischer-Tropsch
derived" refers to a hydrocarbon stream in which a substantial
portion, except for added hydrogen, is derived from a
Fischer-Tropsch process regardless of subsequent processing steps.
Accordingly, a "Fischer-Tropsch derived bottoms" refers to a
hydrocarbon product recovered from the bottom of a fractionation
column, usually a vacuum column, which was initially derived from
the Fischer-Tropsch process. When referring to conventional base
oils, this disclosure is referring to conventional petroleum
derived lubricating base oils produced using petroleum refining
processes well documented in the literature and known to those
skilled in the art. The term "distillate base oil" refers to either
a "Fischer-Tropsch derived" or "conventional" base oil recovered as
a side stream from a fractionation column as opposed to the
"bottoms".
[0009] As used in this disclosure the word "comprises" or
"comprising" is intended as an open-ended transition meaning the
inclusion of the named elements, but not necessarily excluding
other unnamed elements. The phrase "consists essentially of" or
"consisting essentially of" is intended to mean the exclusion of
other elements of any essential significance to the composition.
The phrase "consisting of" or "consists of" are intended as a
transition meaning the exclusion of all but the recited elements
with the exception of only minor traces of impurities.
SUMMARY OF THE INVENTION
[0010] In its broadest aspect the present invention is directed to
a method for improving the lubricating properties of a distillate
base oil characterized by a pour point of 0 degrees C. or less and
a boiling range having the 10 percent point falling between about
625 degrees F. and about 790 degrees F. and the 90 percent point
falling between about 725 degrees F. and about 950 degrees F., the
method comprises blending with said distillate base oil a
sufficient amount of a pour point depressing base oil blending
component to reduce the pour point of the resulting base oil blend
at least 3 degrees C. below the pour point of the distillate base
oil, wherein the pour point depressing base oil blending component
is an isomerized Fischer-Tropsch derived bottoms product having a
pour point that is at least 3 degrees C. higher than the pour point
of the distillate base oil. For example, if the target pour point
of the distillate base oil is -9 degrees C. and the pour point of
the distillate base oil is greater than -9 degrees C., an amount of
the pour point depressing base oil blending component of the
invention will be blended with the distillate base oil in
sufficient proportion to lower the pour point of the blend to the
target value. The isomerized Fischer-Tropsch derived bottoms
product used to lower the pour point of the lubricating base oil is
usually recovered as the bottoms from the vacuum column of a
Fischer-Tropsch operation. The average molecular weight of the pour
point depressing base oil blending component usually will fall
within the range of from about 600 to about 1100 with an average
molecular weight between about 700 and about 1000 being preferred.
Typically the pour point of the pour point depressing base oil
blending component will be between about -9 degrees C. and about 20
degrees C. The 10 percent point of the boiling range of the pour
point depressing base oil blending component usually will be within
the range of from about 850 degrees F. and about 1050 degrees
F.
[0011] The invention is also directed to a pour point depressing
base oil blending component suitable for lowering the pour point of
a base oil which comprises an isomerized Fischer-Tropsch derived
bottoms product having an average molecular weight between about
600 and about 1100 and an average degree of branching in the
molecules between about 6.5 and about 10 alkyl branches per 100
carbon atoms.
[0012] The distillate base oil may be either a conventional
petroleum-derived base oil or a Fischer-Tropsch derived base oil.
It may be a light neutral base oil or a medium neutral base oil.
Depending upon the amount of pour point depressing base oil
blending component blended with the distillate base oil, the cloud
point of the base oil blend may be raised. Therefore, if the cloud
point of the base oil blend is a critical specification, the
distillate base oil must have a cloud point no higher than the
target cloud point. Preferably the cloud point of the distillate
base oil will be lower than the target specification to allow for
some rise in the cloud point and still meet the specification. Base
oils intended for use in certain finished lubricants often require
a cloud point of 0 degrees C. or less. Therefore, for base oils
intended for those applications, a cloud point below 0 degrees C.
is desirable.
[0013] In addition to lowering the pour point of the distillate
base oil, the present invention also has been observed to increase
the VI. In the case of both pour point and VI, the degree of change
in these values could not have been predicted by only observing the
properties of the individual components. In each case a premium was
observed. That is to say, the pour point of the blend containing
the distillate base oil and the pour point depressing base oil
blending component is not merely a proportional averaging of the
two pour points, but the value obtained is significantly lower than
would be expected. The pour point in many cases has been observed
to be lower than the value for either of the two individual
components. The same is also true for VI. The VI of the mixture is
not the proportional average of the VI's for the two components but
is higher than would be expected, and in many cases, the VI of the
base oil blend will exceed the VI of either component. Preferably,
in the base oil blend, the pour point depressing base oil blending
component will comprise no more than about 15 weight percent of the
base oil of the blend, more preferably 7 weight percent or less,
and most preferably 3.5 weight percent or less. Since it is usually
desirable to maintain as low a cloud point as possible for the base
oil blend, only the minimum amount of the pour point depressing
base oil blending component necessary to meet the pour point and/or
VI specifications is added to the distillate base oil. The pour
point depressing base oil component will also increase the
viscosity of the blend. Therefore the amount of the pour point
depressing base oil component which can be added may also be
limited by the upper viscosity limit.
DETAILED DESCRIPTION OF THE INVENTION
[0014] Pour point refers to the temperature at which a sample of
the distillate base oil or the isomerized Fischer-Tropsch derived
bottoms will begin to flow under carefully controlled conditions.
In this disclosure, where pour point is given, unless stated
otherwise, it has been determined by standard analytical method
ASTM D-5950 or its equivalent. Cloud point is a measurement
complementary to the pour point, and is expressed as a temperature
at which a sample begins to develop a haze under carefully
specified conditions. Cloud points in this specification were
determined by ASTM D-5773-95 or its equivalent. Kinematic viscosity
described in this disclosure was measured by ASTM D-445 or its
equivalent. VI may be determined by using ASTM D-2270-93 (1998) or
its equivalent. As used herein, an equivalent analytical method to
the standard reference method refers to any analytical method which
gives substantially the same results as the standard method.
Molecular weight may be determined by ASTM D-2502, ASTM D-2503, or
other suitable method. For use in association with this invention,
molecular weight is preferably determined by ASTM D-2503-02.
[0015] The branching properties of the pour point depressing base
oil blending component of the present invention was determined by
analyzing a sample of oil using carbon-13 NMR according to the
following seven-step process. References cited in the description
of the process provide details of the process steps. Steps 1 and 2
are performed only on the initial materials from a new process.
[0016] 1) Identify the CH branch centers and the CH.sub.3 branch
termination points using the DEPT Pulse sequence (Doddrell, D. T.;
D. T. Pegg; M. R. Bendall, Journal of Magnetic Resonance 1982, 48,
323ff.).
[0017] 2) Verify the absence of carbons initiating multiple
branches (quaternary carbons) using the APT pulse sequence (Patt,
S. L.; J. N. Shoolery, Journal of Magnetic Resonance 1982, 46,
535ff.).
[0018] 3) Assign the various branch carbon resonances to specific
branch positions and lengths using tabulated and calculated values
(Lindeman, L. P., Journal of Qualitative Analytical Chemistry 43,
1971 1245ff; Netzel, D. A., et. al., Fuel, 60, 1981, 307ff).
EXAMPLES
[0019] TABLE-US-00001 Branch NMR Chemical Shift (ppm) 2-methyl 22.5
3-methyl 19.1 or 11.4 4-methyl 14.0 4+methyl 19.6 Internal ethyl
10.8 Propyl 14.4 Adjacent methyls 16.7
[0020] 4) Quantify the relative frequency of branch occurrence at
different carbon positions by comparing the integrated intensity of
its terminal methyl carbon to the intensity of a single carbon
(=total integral/number of carbons per molecule in the mixture).
For the unique case of the 2-methyl branch, where both the terminal
and the branch methyl occur at the same resonance position, the
intensity was divided by two before doing the frequency of branch
occurrence calculation. If the 4-methyl branch fraction is
calculated and tabulated, its contribution to the 4+methyls must be
subtracted to avoid double counting.
[0021] 5) Calculate the average carbon number. The average carbon
number may be determined with sufficient accuracy for lubricant
materials by dividing the molecular weight of the sample by 14 (the
formula weight of CH.sub.2).
[0022] 6) The number of branches per molecule is the sum of the
branches found in step 4.
[0023] 7) The number of alkyl branches per 100 carbon atoms is
calculated from the number of branches per molecule (step 6) times
100/average carbon number.
[0024] Measurements can be performed using any Fourier Transform
NMR spectrometer. Preferably, the measurements are performed using
a spectrometer having a magnet of 7.0T or greater. In all cases,
after verification by Mass Spectrometry, UV or an NMR survey that
aromatic carbons were absent, the spectral width was limited to the
saturated carbon region, about 0-80 ppm vs. TMS
(tetramethylsilane). Solutions of 15-25 percent by weight in
chloroform-d1 were excited by 45 degrees pulses followed by a 0.8
sec acquisition time. In order to minimize non-uniform intensity
data, the proton decoupler was gated off during a 10 sec delay
prior to the excitation pulse and on during acquisition. Total
experiment times ranged from 11-80 minutes. The DEPT and APT
sequences were carried out according to literature descriptions
with minor deviations described in the Varian or Bruker operating
manuals.
[0025] DEPT is Distortionless Enhancement by Polarization Transfer.
DEPT does not show quaternaries. The DEPT 45 sequence gives a
signal all carbons bonded to protons. DEPT 90 shows CH carbons
only. DEPT 135 shows CH and CH.sub.3 up and CH.sub.2 180 degrees
out of phase (down). APT is Attached Proton Test. It allows all
carbons to be seen, but if CH and CH.sub.3 are up, then
quaternaries and CH.sub.2 are down. The sequences are useful in
that every branch methyl should have a corresponding CH. And the
methyls are clearly identified by chemical shift and phase. Both
are described in the references cited. The branching properties of
each sample were determined by C-13 NMR using the assumption in the
calculations that the entire sample was iso-paraffinic. Corrections
were not made for n-paraffins or naphthenes, which may have been
present in the oil samples in varying amounts. The naphthenes
content may be measured using Field Ionization Mass Spectroscopy
(FIMS).
[0026] Since conventional petroleum derived hydrocarbons and
Fischer-Tropsch derived hydrocarbons comprise a mixture of varying
molecular weights having a wide boiling range, this disclosure will
refer to the 10 percent point and the 90 percent point of the
respective boiling ranges. The 10 percent point refers to that
temperature at which 10 weight percent of the hydrocarbons present
within that cut will vaporize at atmospheric pressure. Similarly,
the 90 percent point refers to the temperature at which 90 weight
percent of the hydrocarbons present will vaporize at atmospheric
pressure. In this disclosure when referring to boiling range
distribution, the boiling range between the 10 percent and 90
percent boiling points is what is being referred to. For samples
having a boiling range above 1000 degrees F., the boiling range
distributions in this disclosure were measured using the standard
analytical method D-6352 or its equivalent. For samples having a
boiling range below 1000 degrees F., the boiling range
distributions in this disclosure were measured using the standard
analytical method D-2887 or its equivalent. It will be noted that
only the 10 percent point is used when referring to the pour point
depressing base oil blending component, since it is derived from a
bottoms fraction which makes the 90 percent point or upper boiling
limit irrelevant.
The Isomerized Fischer-Tropsch Bottoms
[0027] As already explained, the isomerized Fischer-Tropsch derived
product which is employed as a pour point depressing base oil
blending component in the present invention is separated as a high
boiling bottoms fraction from the hydrocarbons produced during a
Fischer-Tropsch synthesis reaction. The Fischer-Tropsch syncrude as
initially recovered from the Fischer-Tropsch synthesis contains a
waxy fraction that is normally a solid at room temperature. The
waxy fraction may be produced directly from the Fischer-Tropsch
syncrude or it may be prepared from the oligomerization of lower
boiling Fischer-Tropsch derived olefins. Regardless of the source
of the Fischer-Tropsch wax, it must contain hydrocarbons boiling
above about 900 degrees F. in order to produce the bottoms used in
preparing the pour point depressing base oil blending component of
the present invention. In order to improve the pour point and VI,
the Fischer-Tropsch wax is isomerized to introduce favorable
branching into the molecules. The isomerized Fischer-Tropsch
derived wax will usually be sent to a vacuum column where the
various distillate base oil cuts are collected. These distillate
base oil fractions may be used to prepare the lubricating base oil
blends of the present invention, or they may be cracked into lower
boiling products, such as diesel or naphtha. The bottoms material
collected from the vacuum column comprises a mixture of high
boiling hydrocarbons which is used to prepare the pour depressing
base oil blending component of the present invention. In addition
to isomerization and fractionation, the Fischer-Tropsch derived
waxy fraction may undergo various other operations, such as
hydrocracking, hydrotreating, and hydrofinishing. The pour point
depressing base oil blending component of the present invention is
not an additive in the normal use of this term within the art,
since it is really only a high boiling fraction recovered from the
Fischer-Tropsch syncrude.
[0028] It has been found that when the isomerized Fischer-Tropsch
derived bottoms is used to reduce the pour point, the pour point of
the lubricating base oil blend will be below the pour point of both
the pour point depressing base oil blending component and the
distillate base oil. Therefore, it is usually not necessary to
reduce the pour point of the Fischer-Tropsch derived bottoms to the
target pour point of the lubricating base oil blend. Accordingly,
the actual degree of isomerization need not be as high as might
otherwise be expected, and the isomerization reactor may be
operated at a lower severity with less cracking and less yield
loss. It has been found that the Fischer-Tropsch derived bottoms
should not be over isomerized or its ability to act as a pour point
depressing base oil blending component will be compromised.
Accordingly, the average degree of branching in the molecules of
the bottoms should fall within the range of from about 6.5 to about
10 alkyl branches per 100 carbon atoms.
[0029] The pour point depressing base oil blending component will
have an average molecular weight between about 600 and about 1100,
preferably between about 700 and about 1000. The kinematic
viscosity at 100 degrees C. will usually fall within the range of
from about 8 cSt to about 22 cSt. The 10 percent point of the
boiling range of the bottoms typically will fall between about 850
degrees F. and about 1050 degrees F. Generally, the higher
molecular weight hydrocarbons are more effective as pour point
depressing base oil blending components than the lower molecular
weight hydrocarbons. Consequently, higher cut points in the
fractionation column which result in a higher boiling bottoms
material are usually preferred when preparing the pour point
depressing base oil blending component. The higher cut point also
has the advantage of resulting in a higher yield of the distillate
base oil fractions.
[0030] It has also been found that by solvent dewaxing the
isomerized bottoms material, the effectiveness of the pour point
depressing base oil blending component may be enhanced. The waxy
product separated during solvent dewaxing from the Fischer-Tropsch
derived bottoms has been found to display improved pour point
depressing properties. The oily product recovered after the solvent
dewaxing operation while displaying some pour point depressing
properties is less effective than the waxy product.
The Distillate Base Oil
[0031] The separation of Fischer-Tropsch derived products and
petroleum derived products into various fractions having
characteristic boiling ranges is generally accomplished by either
atmospheric or vacuum distillation or by a combination of
atmospheric and vacuum distillation. As used in this disclosure,
the term "distillate fraction" or "distillate" refers to a side
stream product recovered either from an atmospheric fractionation
column or from a vacuum column as opposed to the "bottoms" which
represents the residual higher boiling fraction recovered from the
bottom of the column. Atmospheric distillation is typically used to
separate the lighter distillate fractions, such as naphtha and
middle distillates, from a bottoms fraction having an initial
boiling point above about 700 degrees F. to about 750 degrees F.
(about 370 degrees C. to about 400 degrees C.). At higher
temperatures thermal cracking of the hydrocarbons may take place
leading to fouling of the equipment and to lower yields of the
heavier cuts. Vacuum distillation is typically used to separate the
higher boiling material, such as the distillate base oil fractions
which are used in carrying out the present invention. Thus the
distillate base oil and the Fischer-Tropsch derived bottoms product
are usually recovered from the vacuum distillation column, although
the invention is not intended to be limited to any particular mode
of separating the components.
[0032] The distillate base oil fractions used in carrying out the
invention are characterized by a pour point of 0 degrees C. or less
and a boiling range having the 10 percent point falling between
about 625 degrees F. and about 790 degrees F. and the 90 percent
point falling between about 725 degrees F. and about 950 degrees F.
Usually the 90 percent point will fall between about 725 degrees F.
and 900 degrees F. The distillate base oil may be either
conventionally derived from the refining of petroleum or syncrude
recovered from a Fischer-Tropsch synthesis reaction. The distillate
base oil may be a light neutral base oil or a medium neutral base
oil. The distillate base oil will usually have a kinematic
viscosity at 100 degrees C. between about 2.5 cSt and about 7 cSt.
Preferably, the viscosity will be between about 3 cSt and about 7
cSt at 100 degrees C. If the target cloud point for the lubricating
base oil blend is 0 degrees C., the cloud point of the distillate
base oil preferably should be 0 degrees C. or less.
[0033] If the distillate base oil contains a high proportion of
wax, such as with a Fischer-Tropsch derived base oil, it is usually
necessary to dewax the base oil. This may be accomplished by either
catalytic dewaxing or by solvent dewaxing. Hydroisomerization which
is used in the preparation of the isomerized Fischer-Tropsch
derived bottoms may also be advantageously used to dewax the
distillate base oil fraction. Hydroisomerization is particularly
preferred when both the distillate base oil and the pour point
depressing base oil blending component are recovered from a
Fischer-Tropsch operation. Typically in such operations the entire
base oil fraction which contains a great amount of wax is
isomerized followed by fractionation in a vacuum column.
[0034] The present invention is particularly advantageous when used
with distillate base oils having a VI of less than 110, since such
base oils are usually unsuitable for preparing high quality
lubricants without the addition of significant amounts of VI
improvers. Due to the VI premium which has been observed when using
the pour point depressing base oil blending component of the
invention, the VI of marginal base oils may be significantly
improved without the use of conventional additives. The pour point
depressing base oil blending component of the present invention by
increasing the VI, makes it possible to upgrade Group II base oils
having a VI of less than 110 up to Group II plus base oils. It is
also possible by using the present invention to upgrade Group II
base oils to Group III base oils.
Lubricating Base Oil Product
[0035] A lubricating base oil blend prepared according to the
process of the present invention will have a kinematic viscosity
greater than about 3 cSt at 100 degrees C. Usually the kinematic
viscosity at 100 degrees C. will not exceed about 8 cSt. The
lubricating base oil blend will also have a pour point below about
-9 degrees C. and a VI that is usually greater than about 90.
Preferably the kinematic viscosity at 100 degrees C. will be
between about 3 cSt and about 7 cSt, the pour point will be about
-15 degrees C. or less, and the VI will be about 100 or higher.
Even more preferably the VI will be 110 or higher. The cloud point
of the lubricating base oil preferably will be 0 degrees C. or
below. The pour point of the lubricating base oil blend will be at
least 3 degrees C. lower than the pour point of the lower viscosity
component of the blend. Preferably, the pour point of the blend
will be at least 6 degrees C. below the pour point of the
distillate base oil and more preferably at least 9 degrees C. below
the pour point of the distillate base oil. At the same time, the VI
of the blend will preferably be raised by at least three numbers
above the VI of the distillate base oil. The properties of the
lubricating base oils prepared using the process of the invention
are achieved by blending the distillate base oil with the minimum
amount of the pour point depressing base oil blending component
necessary to meet the desired specifications for the product.
[0036] In achieving the selected pour points, the pour point
depressing base oil blending component usually will not comprise
more than about 15 weight percent of the base oil blend.
Preferably, it will comprise 7 weight percent or less, and most
preferably the pour point depressing base oil blending component
will comprise 3.5 weight percent or less of the blend. The minimum
amount of the pour point depressing base oil blending component to
meet the desired specifications for pour point and VI are usually
preferred to avoid raising the cloud point and/or viscosity of the
blend to an unacceptable level. At the lower levels of addition,
the effect on cloud point is generally negligible.
[0037] As already noted, when the pour point depressing base oil
blending component is blended with the distillate base oil, a VI
premium is observed. The term "VI premium" refers to a VI boost in
which the VI of the blend is significantly higher than would have
been expected from a mere proportional averaging of the Vi's for
the two fractions. The improvement in VI resulting from the
practice of the present invention makes it possible to produce a
Group III base oil, i.e., a base oil having a VI greater than 120,
from a Group II base oil, i.e., a base oil having a VI between 80
and 120. A Group II plus base oil may also be prepared from a Group
II base oil having a VI below about 110.
[0038] In order to qualify as a Group II base oil, the base oil
must contain 300 ppm of sulfur or less. In the case of a
conventional petroleum derived distillate base oil having a
marginal sulfur content, blending in the isomerized high boiling
Fischer-Tropsch product may also serve to lower the sulfur content
to meet sulfur specifications. Fischer-Tropsch derived hydrocarbons
contain very low levels of sulfur and, therefore, are ideal for
blending with marginal conventional petroleum derived base oils to
meet sulfur specifications.
[0039] A further advantage of the process of the present invention
is that the volatility of the lubricating base oil blend may be
lowered relative to that of the distillate base oil fraction. The
pour point depressing base oil blending component is characterized
by a very low Noack volatility. Consequently, depending upon how
much of the pour point depressing base oil blending component is
blended with the distillate base oil, the lubricating base oil
blend may have a lower Noack volatility than the distillate base
oil fraction alone.
[0040] Lubricating base oil blends prepared according to the
process of the present invention display a distinctive boiling
range profile. Therefore, the lubricating base oil blend comprising
the distillate base oil and the pour point depressing base oil
blending component may be described as a lubricating base oil
having a viscosity at 100 degrees C. between about 3 cSt and about
8 cSt and further containing a high boiling fraction boiling above
about 900 degrees F. and a low boiling fraction boiling below about
900 degrees F., wherein when the high boiling fraction is distilled
out the low boiling fraction will have a higher pour point than the
entire lubricating base oil. The low boiling fraction corresponds
to the distillate base oil, and the high boiling fraction
corresponds to the pour point depressing base oil blending
component.
[0041] Lubricating base oil blends of the invention may be
identified by using simulated distillation to determine the 900
degrees F. weight percent point. For instance, if the blend is 85
weight percent below 900 degrees F., one would distill off, by
conventional distillation methods well known to those skilled in
the art, 85 weight percent of the blend to get a 900 degrees F.
cutpoint.
Hydroisomerization
[0042] Hydroisomerization, or for the purposes of this disclosure
simply "isomerization", is intended to improve the cold flow
properties of Fischer-Tropsch derived or petroleum derived wax by
the selective addition of branching into the molecular structure.
In the present invention, it is essential that the Fischer-Tropsch
derived bottoms be isomerized at some point during its processing
in order to make it suitable for use as a pour point depressing
base oil blending component. Waxy petroleum derived base oils also
may be advantageously isomerized in preparing them for use in the
present invention.
[0043] Isomerization ideally will achieve high conversion levels of
the wax to non-waxy iso-paraffins while at the same time minimizing
the conversion by cracking. Since wax conversion can be complete,
or at least very high, this process typically does not need to be
combined with additional dewaxing processes to produce a high
boiling Fischer-Tropsch product with an acceptable pour point.
Isomerization operations suitable for use with the present
invention typically use a catalyst comprising an acidic component
and may optionally contain an active metal component having
hydrogenation activity. The acidic component of the catalyst
preferably includes an intermediate pore SAPO, such as SAPO-11,
SAPO-31, and SAPO41, with SAPO-11 being particularly preferred.
Intermediate pore zeolites, such as ZSM-22, ZSM-23, SSZ-32, ZSM-35,
and ZSM48, also may be used in carrying out the isomerization.
Typical active metals include molybdenum, nickel, vanadium, cobalt,
tungsten, zinc, platinum, and palladium. The metals platinum and
palladium are especially preferred as the active metals, with
platinum most commonly used.
[0044] The phrase "intermediate pore size", when used herein,
refers to an effective pore aperture in the range of from about 4.0
to about 7.1 Angstrom (as measured along both the short or long
axis) when the porous inorganic oxide is in the calcined form.
Molecular sieves having pore apertures in this range tend to have
unique molecular sieving characteristics. Unlike small pore
zeolites such as erionite and chabazite, they will allow
hydrocarbons having some branching into the molecular sieve void
spaces. Unlike larger pore zeolites such as faujasites and
mordenites, they are able to differentiate between n-alkanes and
slightly branched alkenes, and larger alkanes having, for example,
quaternary carbon atoms. See U.S. Pat. No. 5,413,695. The term
"SAPO" refers to a silicoaluminophosphate molecular sieve such as
described in U.S. Pat. Nos. 4,440,871 and 5,208,005.
[0045] In preparing those catalysts containing a non-zeolitic
molecular sieve and having a hydrogenation component, it is usually
preferred that the metal be deposited on the catalyst using a
non-aqueous method. Non-zeolitic molecular sieves include
tetrahedrally-coordinated [AlO2] and [PO2] oxide units which may
optionally include silica. See U.S. Pat. No. 5,514,362. Catalysts
containing non-zeolitic molecular sieves, particularly catalysts
containing SAPO's, on which the metal has been deposited using a
non-aqueous method have shown greater selectivity and activity than
those catalysts which have used an aqueous method to deposit the
active metal. The non-aqueous deposition of active metals on
non-zeolitic molecular sieves is taught in U.S. Pat. No. 5,939,349.
In general, the process involves dissolving a compound of the
active metal in a non-aqueous, non-reactive solvent and depositing
it on the molecular sieve by ion exchange or impregnation.
Solvent Dewaxing
[0046] In conventional refining, solvent dewaxing is used to remove
small amounts of any remaining waxy molecules from the lubricating
base oil after hydroisomerization. In the present invention,
solvent dewaxing may optionally be used to enhance the pour point
depressing properties of the isomerized Fischer-Tropsch derived
bottoms. In this instance, the waxy fraction recovered from the
solvent dewaxing step was found to be more effective in lowering
pour point than the oily fraction. Solvent dewaxing is done by
dissolving the Fischer-Tropsch derived bottoms in a solvent, such
as methyl ethyl ketone, methyl iso-butyl ketone, or toluene. See
U.S. Pat. Nos. 4,477,333; 3,773,650; and 3,775,288.
[0047] The following examples are intended to illustrate the
invention but are not to be construed as a limitation on the scope
of the invention.
EXAMPLES
Example 1
[0048] A hydrotreated Fischer-Tropsch wax (having the
specifications shown in Table I) was hydroisomerized over a
Pt/SAPO-11 catalyst containing 15 weight percent alumina binder.
Run conditions included a liquid hourly space velocity (LHSV) of
1.0, a total pressure of 1000 psig, a once-through hydrogen rate of
5300 SCF/bbl, and a reactor temperature of 680 degrees F. The
catalyst was pre-sulfided at the start of the run using DMDS in
dodecane at 645 degrees F., with 6 moles S fed per mole of Pt. The
product from the hydroisomerization reactor went directly to a
hydrofinishing reactor containing a Pt--Pd/SiO2--Al2O3 catalyst, at
a LHSV of 2.1, and a temperature of 450 degrees F., with the same
pressure and hydrogen rate as in the isomerization reactor. The
product from this reactor went to a high pressure separator, with
the liquid going to a stripper, then to product collection.
[0049] The 650 degrees F+ bottoms product (having the
specifications shown in Table II), which had a pour point of -19
degrees C. was fractionated into a 650-750 degrees F. cut, a
750-850 degrees F. cut, an 850-950 degrees F. cut, and a 950
degrees F+ bottoms. Inspections on these cuts are given in Table
II, showing all the cuts to have pour points greater than the -19
degrees C. of the whole 650 degrees F+ bottoms. Recombining the
cuts in the same proportions as in the distillation again gave a
composite of -19 degrees C. pour point.
[0050] A blend of 85 weight percent of the 650-750 degrees F. 2.6
cSt cut and 15 weight percent of the 950 degrees F+ bottoms was
prepared. The blend had a pour point of -27 degrees C. (Table III),
lower than the pour point of either cut separately. TABLE-US-00002
TABLE I Hydrotreated FT Wax Gravity, .degree. API 40.3 Pour Point,
.degree. C. +79 Sulfur, ppm 2 Nitrogen, ppm 1 Oxygen, Wt. % 0.11
Sim. Dist., Wt. %, .degree. F. ST/5 479/590 10/30 639/728 50 796
70/90 884/1005 95/EP 1062/1187
[0051] TABLE-US-00003 TABLE II Inspections of 650.degree. F.+ of FT
Wax Isomerized at 1000 psig over Pt/SAPO-11 Gravity, .degree. API
42.1 Pour Point, .degree. C. -19 Cloud Point, .degree. C. +10
Viscosity, 40.degree. C., cSt 17.55 100.degree. C., cSt 4.303 VI
161 650-750.degree. F. 750-850.degree. F. 850-950.degree. F.
950.degree. F.+ Fraction, Wt. % 37.7 27.8 18.4 16.1 Gravity,
.degree. API 43.9 42.5 40.6 38.0 Pour Point, .degree. C. -17 -9 -2
+3 Cloud Point, .degree. C. -16 -4 +37 +29 Vis- 40.degree. C.,
9.032 14.65 27.99 88.13 cos- cSt ity, 100.degree. C., 2.648 3.742
5.957 14.19 cSt VI 135 151 166 167 Sim. Dist., Wt. %, .degree. F.
ST/5 612/648 656/693 740/791 884/927 10/30 658/685 711/756 812/849
949/1004 50 710 790 894 1052 70/90 739/791 826/882 929/980
1104/1186 95/EP 819/896 912/990 1003/1061 1221/1285
[0052] TABLE-US-00004 TABLE III Inspections of Blend of 85/15 Wt. %
650-750.degree. F./950.degree. F.+ Cuts of Table II Pour Point,
.degree. C. -27 Cloud Point, .degree. C. +6 Viscosity, 40.degree.
C., cSt 12.71 100.degree. C., cSt 3.426 VI 154
Example 2
[0053] Another 650 degrees F+bottoms product (Table IV) was
collected from the same run as in Example 1, except that the total
pressure in the reactors was 300 psig and the temperature in the
hydroisomerization reactor was 670 degrees F. The product was
fractionated into a 650-730 degrees F. cut, a 730-850 degrees F.
cut, and an 850 degrees F+cut. Inspections on these cuts are given
in Table IV.
[0054] A blend of 63 weight percent of the 730-850 degrees F. 3.5
cSt cut and 37 weight percent of the 850 degrees F+cut was prepared
(Table V). The blend had a pour point of -13 degrees C., lower than
the pour point of either cut separately. TABLE-US-00005 TABLE IV
Inspections of 650.degree. F.+ of FT Wax Isomerized at 300 psig
over Pt/SAPO-11 Gravity, .degree. API 42.4 Pour Point, .degree. C.
-16 Cloud Point, .degree. C. +13 Viscosity, 40.degree. C., cSt
17.41 100.degree. C., cSt 4.320 VI 166 650-730.degree. F.
730-850.degree. F. 850.degree. F.+ Fraction, Wt. % 28.7 29.9 41.4
Gravity, .degree. API 44.4 42.9 39.6 Pour Point, .degree. C. -19 -8
-5 Cloud Point, .degree. C. -12 -5 +24 Viscosity, 40.degree. C.,
cSt 8.312 12.99 45.11 100.degree. C., cSt 2.522 3.460 8.584 VI 140
151 171 Sim. Dist., Wt. %, .degree. F. ST/5 597/636 646/684 767/805
10/30 648/676 701/742 827/886 50 699 773 939 70/90 726/773 805/855
1006/1119 95/EP 799/884 882/963 1180/1322
[0055] TABLE-US-00006 TABLE V Inspections of Blend of 63/37 Wt, %
730-850.degree. F./850.degree. F.+ Cuts of Table IV Pour Point,
.degree. C. -13 Cloud Point, .degree. C. +13 Viscosity, 40.degree.
C., cSt 20.83 100.degree. C., cSt 4.888 VI 168
Example 3
[0056] A run similar to that in Example 2 was carried out on a feed
similar to that of Table I.
[0057] The 650 degrees F+bottoms product was cut into three
fractions, a 650-730 degrees F. cut, a 730-930 degrees F. cut, a
930-1000 degrees F. cut, and a 1000 degrees F+ bottoms. Inspections
of the three highest boiling cuts are given in Table VI.
TABLE-US-00007 TABLE VI Inspections of 650.degree. F.+ of
Isomerized FT Wax 730-930.degree. F. 930-1000.degree. F.
1000.degree. F.+ Pour Point, .degree. C. -17 -17 -6 Cloud Point,
.degree. C. -10 +1 +20 Viscosity, 40.degree. C., cSt 18.3 46.5
114.0 100.degree. C., cSt 4.3 8.3 16.6 VI 147 156 157 Sim. Dist.,
Wt. %, .degree. F. ST/5 665/708 940/978 10/30 727/777 996/1040 50
818 1077 70/90 861/920 1121/1196 95/EP 949/1023 1235/1310
[0058] Blends of the 730-930 degrees F. cut and the 1000 degrees F+
cut were prepared. Results are shown in Table VII. These show the
blends to have lower pour points than either fraction separately.
In the 85/15 case, the VI is higher than for either fraction
separately. TABLE-US-00008 TABLE VII Inspections on Blends of the
730-930.degree. F. Cut and 1000.degree. F.+ Cut from Table VI
Blend, Wt./Wt. % 85/15 93/7 96.5/3.5 Pour Point, .degree. C. -28
-28 -22 Cloud Pt, .degree. C. +6 0 -4 Viscosity, 40.degree. C., cSt
24.06 20.95 19.57 100.degree. C., cSt 5.282 4.759 4.515 VI 161 154
150
Comparative Example A
[0059] Blends of the 930-1000 degrees F. cut from Table VI and the
1000 degrees F+ cut were prepared. Results are shown in Table VIII.
These show the pour point reduction of these blends to be
considerably less than in Example 3. TABLE-US-00009 TABLE VIII
Inspections on Blends of the 930-1000.degree. F. Cut and
1000.degree. F.+ Cut from Table VI Blend, Wt./Wt. % 93/7 96.5/3.5
Pour Point, .degree. C. -15 -12 Cloud Pt, .degree. C. -2 +5
Viscosity, 40.degree. C., cSt 49.35 47.91 100.degree. C., cSt 8.753
8.556 VI 157 157
Example 4
[0060] The hydrotreated FT wax of Table I was isomerized over a
Pt/SSZ-32 catalyst at the same conditions as in Example 1, except
for an isomerization temperature of 690 degrees F.
[0061] The 650 degrees F+ bottoms product (Table IX), which had a
pour point of -21 degrees C. was fractionated into a 650-750
degrees F. cut, a 750-850 degrees F. cut, a 850-950 degrees F. cut,
and a 950 degrees F+ bottoms. Inspections on these cuts are given
in Table IX, showing all the cuts to have pour points greater than
the -21 degrees C. of the whole 650 degrees F+ bottoms. Recombining
the cuts in the same proportions as in the distillation gave a
composite of -25 degrees C. pour point. A blend of 85 weight
percent of the 650-750 degrees F. 3.0 cSt cut and 15 weight percent
of the 950 degrees F+ bottoms was prepared. The blend had a pour
point of -26 degrees C. (Table X), lower than the pour point of
either cut separately. Furthermore, the VI of the 3.8 cSt blend was
7 numbers higher than the 3.8 cSt fraction produced by
isomerization only, and the pour point was 20 degrees C. lower.
TABLE-US-00010 TABLE IX Inspections of 650.degree. F.+ of FT Wax
Isomerized at 1000 psig over Pt/SSZ-32 Gravity, .degree. API 41.1
Pour Point, .degree. C. -21 Cloud Point, .degree. C. +15 Viscosity,
40.degree. C., cSt 22.06 100.degree. C., cSt 5.081 VI 169
650-750.degree. F. 750-850.degree. F. 850-950.degree. F.
950.degree. F.+ Fraction, Wt. % 23.6 36.3 23.6 16.4 Gravity,
.degree. API 43.6 42.3 40.6 37.5 Pour Point, .degree. C. -13 -6 -8
-1 Cloud Point, .degree. C. -9 -2 +12 +36 Vis- 40.degree. C., 10.74
15.36 29.91 87.71 cos- cSt ity, 100.degree. C., 3.007 3.876 6.278
13.95 cSt VI 142 153 167 164 Sim. Dist., Wt. %, .degree. F. ST/5
636/678 675/707 736/801 892/932 10/30 690/716 723/764 822/869
953/1003 50 737 796 902 1047 70/90 764/808 829/880 937/987
1093/1169 95/EP 833/904 906/975 1009/1078 1202/1264
[0062] TABLE-US-00011 TABLE X Inspections of Blend of 85/15 Wt. %
650-750.degree. F./950.degree. F.+ Cuts of Table IX Pour Point,
.degree. C. -26 Cloud Point, .degree. C. +10 Viscosity, 40.degree.
C., cSt 14.83 100.degree. C., cSt 3.835 VI 160
Comparative Example B
[0063] The 1000 degrees F+ bottoms of Table VI was solvent dewaxed
at -30 degrees C. to give a dewaxed oil fraction of 14.7 weight
percent and a waxy fraction of 84.8 weight percent. Adding 1 weight
percent of the dewaxed oil fraction to the 730-930 degrees F.
fraction of Table VI gave a blend of -13 degrees C. pour point,
higher than the pour point of the 730-930 degrees F. fraction.
Example 5
[0064] The wax fraction from Comparative Example B was solvent
dewaxed at -10 degrees C. to give a dewaxed oil fraction of 79.3
weight percent, and a waxy fraction of 20.2 weight percent.
Inspections of these fractions are given in Table XI.
TABLE-US-00012 TABLE XI Inspections of the Fractions from Solvent
Dewaxing the 1000.degree. F.+ Waxy Fraction from Comparative
Example B at -10.degree. C. Fraction Dewaxed Oil Waxy Fraction Pour
Point, .degree. C. -5 +10 Cloud Point, .degree. C. +18 +30
Viscosity, 40.degree. C., cSt 114.4 127.5 100.degree. C., cSt 16.72
18.74 VI 159 166
[0065] The C-13 NMR results of the waxy fraction is shown below.
TABLE-US-00013 MW 802 Number of Carbons 57.29 NMR Analysis 2-methyl
0.25 3-methyl 0.33 4-methyl 0.55 5+ methyl 2.12 Internal ethyl 0.92
Adjacent methyl 0.17 Internal Propyl 0.25 Sum 4.60 Alkyl Branches
per Molecule 4.60 Alkyl Branches per 100 Carbons 8.03 Raw Data
Total Carbon Integral 342.5 2-integral 3 3-integral 2 4-integral
4.8 5+ integral 16 Internal ethyl integral 5.5 Adjacent methyls 1
Internal propyls 1.5 Epsilon carbons 87 Divisions per carbon 5.98
Methyl protons 160.4 Total protons 825.26
[0066] Blends with the 730-930 degrees F. fraction of Table VI were
prepared. Results are shown in Table XII. These show the waxy
fraction to be more effective at reducing pour point than the
dewaxed oil fraction, requiring only 1 weight percent to lower the
pour point of the 730-930 degrees F. cut from -17 degrees C. to -24
degrees C. TABLE-US-00014 TABLE XII Inspections of Blends of
730-930.degree. F. Cut of Table VI with the 1000.degree. F.+
Dewaxed Oil (DWO) or Waxy Fractions of Example 5 Blend, Wt./Wt. %
94/6 97/3 99/1 1000.degree. F.+ Blend DWO DWO Waxy Component Pour
Point, .degree. C. -26 -23 -24 Cloud Pt, .degree. C. -4 -7 -7
Viscosity, 40.degree. C., cSt 20.42 19.13 18.65 100.degree. C., cSt
4.692 4.481 4.366 VI 155 154 149
Example 6
[0067] A high pour point commercial 100N base oil (Table XIII) was
blended at a 93/7 weight percent ratio with the 1000 degrees F+
bottoms of Table VI. Results are given in Table XIV. These results
show the 1000 degrees F+ bottoms effective at reducing the pour
point of the 100N base oil, as well as producing a substantial
increase in VI of 11 numbers. TABLE-US-00015 TABLE XIII Inspections
of High Pour 100N Base Oil Pour Point, .degree. C. -10 Cloud Point,
.degree. C. -8 Viscosity, 40.degree. C. cSt 19.52 100.degree. C.,
cSt 4.027 VI 103
[0068] TABLE-US-00016 TABLE XIV Inspections of a 93/7 Wt./Wt. %
Blend of the 100N Base Oil of Table XIII and the 1000.degree. F.+
Bottoms of Table VI Pour Point, .degree. C. -15 Cloud Point,
.degree. C. -2 Viscosity, 40.degree. C., cSt 22.30 100.degree. C.,
cSt 4.487 VI 114
Comparative Example C
[0069] An 85/15 weight percent blend was made using the 650-750
degrees F. cut and the 850-950 degrees F. cut of Table II. This
gave a pour point for the blend of -16 degrees C., much higher than
the -27 degrees C. for the 650-750 degrees F./950 degrees F+ blend
of Table III. The VI of the blend was 141, well below the 154 of
the blend of Table III, despite the 850-950 degrees F. and 950
degrees F+ fractions having about the same VI.
Comparative Example D
[0070] An 85/15 weight percent blend was made using the 650-750
degrees F. cut and the 850-950 degrees F. cut of Table IX. This
gave a pour point for the blend of -8 degrees C., much higher than
the -26 degrees C. for the 650-750 degrees F./950 degrees F+ blend
of Table X. The VI of the blend was 149, well below the 160 of the
blend of Table X, despite the 850-950 degrees F. fraction having a
higher VI than the 950 degrees F+ fraction.
* * * * *