U.S. patent application number 14/904753 was filed with the patent office on 2016-06-16 for process to prepare two or more base oils.
The applicant listed for this patent is SHELL OIL COMPANY. Invention is credited to David John WEDLOCK.
Application Number | 20160168490 14/904753 |
Document ID | / |
Family ID | 48783087 |
Filed Date | 2016-06-16 |
United States Patent
Application |
20160168490 |
Kind Code |
A1 |
WEDLOCK; David John |
June 16, 2016 |
PROCESS TO PREPARE TWO OR MORE BASE OILS
Abstract
The present invention provides a process to prepare two or more
base oils, which process at least comprises the following steps:
(a) providing a paraffmic hydrocarbon feedstock stream; (b)
subjecting a paraffmic hydrocarbon feedstock stream provided in
step (a) to a hydrocracking/hydroisomerization step to obtain an at
least partially isomerised product stream; (c) separating the
product stream of step (b), thereby obtaining a lower boiling
fraction and a higher boiling fraction; (d) dewaxing the lower
boiling fraction of step (c) to obtain a light base oil; and (e)
dewaxing the higher boiling fraction of step (c) to obtain a heavy
base oil.
Inventors: |
WEDLOCK; David John;
(Chester, Chesire, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SHELL OIL COMPANY |
Houston |
TX |
US |
|
|
Family ID: |
48783087 |
Appl. No.: |
14/904753 |
Filed: |
July 15, 2014 |
PCT Filed: |
July 15, 2014 |
PCT NO: |
PCT/EP2014/065052 |
371 Date: |
January 13, 2016 |
Current U.S.
Class: |
585/300 |
Current CPC
Class: |
C10M 101/02 20130101;
C10G 65/16 20130101; C10G 45/64 20130101; C10N 2070/00 20130101;
C10G 45/58 20130101; C10G 65/12 20130101; C10G 47/00 20130101; C10N
2020/02 20130101; C10G 45/62 20130101; C10M 177/00 20130101; C10M
2203/1025 20130101; C10N 2020/011 20200501; C10M 101/00 20130101;
C10G 69/00 20130101; C10G 73/02 20130101; C10G 47/18 20130101 |
International
Class: |
C10G 69/00 20060101
C10G069/00; C10M 101/00 20060101 C10M101/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 15, 2013 |
EP |
13176468.0 |
Claims
1. A process to prepare two or more base oils, the process at least
comprising the following steps: (a) providing a paraffinic
hydrocarbon feedstock stream; (b) subjecting a paraffinic
hydrocarbon feedstock stream provided in step (a) to a
hydrocracking/hydroisomerization step to obtain an at least
partially isomerised product stream; (c) separating the product
stream of step (b), thereby obtaining a lower boiling fraction and
a higher boiling fraction; (d) dewaxing the lower boiling fraction
of step (c) to obtain a light base oil; and (e) dewaxing the higher
boiling fraction of step (c) to obtain a heavy base oil.
2. The process according to claim 1, wherein the paraffinic
hydrocarbon feedstock stream is a hydrowax feedstock, a
Fischer-Tropsch product or mixtures thereof.
3. The process according to claim 1, wherein the lower boiling
fraction of step(c), boils in a temperature range of from 350 to
500.degree. C., and the higher boiling fraction of step (c) , boils
in a temperature range of from 425 to 600.degree. C.
4. The process according to claim 1, wherein dewaxing is performed
by means of a catalytic dewaxing process in the presence of a
catalyst comprising a molecular sieve and a group VIII metal.
5. The process according to claim 4, wherein the molecular sieve is
selected from a group consisting of a MTW, MTT, TON type molecular
sieve, ZSM-12, ZSM-48, and EU-2.
6. The process according to claim 4, wherein the Group VIII metal
is platinum or palladium.
7. The process according to claim 4, wherein the catalyst comprises
a silica or titania binder.
8. The process according to claim 1, wherein the catalytically
dewaxed light base oil in step (d) has a cloud point of below
-15.degree. C.
9. The process according to claim 1, wherein the catalytically
dewaxed light base oil in step (d) has a kinematic viscosity at
100.degree. C. from 2.5 to 6.0 mm.sup.2/s.
10. The process according to claim 1, wherein the catalytically
dewaxed light base oil in step (d) has a pour point of below
0.degree. C.
11. The process according to claim 1, wherein steps (d) and (e)
occur simultaneously.
12. The process according to claim 1, wherein the catalytic dewaxed
heavy base oil in step (e) has a cloud point of below -10.degree.
C.
13. The process according to claim 1, wherein the catalytically
dewaxed heavy base oil in step (e) has a kinematic viscosity at
100.degree. C. from 5.0 to 12.0 mm.sup.2/s.
14. The process according to claim 1, wherein the catalytically
dewaxed heavy base oil in step (e) has a pour point of below
-5.degree. C.
15. The process according to claim 1, wherein the light and heavy
base oil are Group II mineral base oils, Group III mineral base
oils, and Group III Fischer-Tropsch derived base oils according to
the definitions of American Petroleum Institute (API) for category
II and III as defined in API publication 1509.
16. The process according to claim 1, wherein the difference
between the cloud point and the pour point of the catalytically
dewaxed light base oil of step (d) and of the heavy base oil of
step (e) is less than 6.degree. C.
Description
[0001] The present invention relates to a process to prepare two or
more base oils.
[0002] It is known to prepare two or more base oils by
catalytically dewaxing of a paraffinic base oil precursor component
of a broad range of carbon numbers in one and in the same device.
For example in WO 02/070631 a process to prepare two or more base
oil grades from a waxy paraffinic Fischer-Tropsch product is
described. In WO 02/070631 first a Fischer-Tropsch derived
distillate base oil precursor fraction, having a viscosity
corresponding to the desired base oil product, is prepared. This
distillate base oil precursor is subsequently subjected to a
catalytic dewaxing step, followed by a final vacuum distillation,
to obtain one of the desired base oils.
[0003] A problem of the process disclosed in WO 02/070631 is that
base oils precursors need to be stored in tanks for each desired
base oil and all the process steps need to be repeated.
Furthermore, the base oil prepared by the process as disclosed in
WO 02/070631 may have large cloud point/pour point
differentials.
[0004] It is an object of the invention to provide a more efficient
method for preparing two or more base oils having different
viscosities.
[0005] It is a further object of the present invention to provide
an alternative method for preparing two or more base oils having
different viscosities.
[0006] One of the above or other objects may be achieved according
to the present invention by providing a process to prepare two or
more base oils, the process at least comprising the following
steps: [0007] (a) providing a paraffinic hydrocarbon feedstock
stream; [0008] (b) subjecting a paraffinic hydrocarbon feedstock
stream provided in step (a) to a hydrocracking/hydroisomerization
step to obtain an at least partially isomerised product stream;
[0009] (c) separating the product stream of step (b), thereby
obtaining a lower boiling fraction and a higher boiling fraction;
[0010] (d) dewaxing the lower boiling fraction of step (c) to
obtain a light base oil; and [0011] (e) dewaxing the higher boiling
fraction of step (c) to obtain a heavy base oil.
[0012] It has now surprisingly been found according to the present
invention that two or more base oils having different viscosities
can be simultaneously prepared on a continuous basis in a
surprisingly simple and elegant manner.
[0013] An important advantage of the present invention is that two
or more base oils are obtained having low cloud point/pour point
differentials.
[0014] Preparation of two or more base oils by catalytically
dewaxing of a paraffinic base oil precursor component with carbon
numbers covering several viscosities in one and the same device may
result in base oils having high cloud point/pour point
differentials. These high cloud point/pour point differentials
demonstrate poor isomerisation of the heavier waxes in the obtained
base oils.
[0015] Base oils with different viscosities according to the
present invention can thus be prepared in a efficient manner having
low cloud point/pour point differentials.
[0016] A further advantage of the present invention is that by
separately but simultaneously catalytic dewaxing the lower and
higher boiling fractions to obtain the light and heavy base oils,
no intermediate tankage is necessary to separately store the lower
and higher boiling fractions prior to individually catalytic
dewaxing of these fractions.
[0017] In step (a) of the process according to the present
invention a paraffinic hydrocarbon feedstock stream is
provided.
[0018] Suitably, the paraffinic hydrocarbon feedstock stream is a
hydrowax feedstock, a Fischer-Tropsch product or mixtures thereof.
Preferably, the paraffinic hydrocarbon feedstock stream is a
Fischer-Tropsch product.
[0019] Various processes to provide a hydrowax are known in the
art. By the term "hydrowax" is meant a mineral feedstock product,
which product is derived from crude oil. Suitably, the hydrowax is
derived from waxy crude oils, by a process comprising contacting
hydrocarbonaceous feedstock derived from a waxy crude oil with a
hydroisomerisation catalyst under hydroisomerising conditions and
is the .about.370.degree. C.+bottoms fraction of a fuels
hydrocracker optimised for automotive gas oil. This process is for
example described in EP-A-0400742.
[0020] Suitably, the density of the hydrowax at 70.degree. C.
according to ASTM D-4052 is between 800 and 850 kg/m.sup.3,
preferably between 810 and 820 kg/m.sup.3, more preferably between
819 and 820 kg/m.sup.3.
[0021] The hydrowax has preferably an initial boiling point of
between 200 to 430.degree. C., more preferably between 228 to
421.degree. C. and most preferably between 322 to 421.degree. C.
and a final boiling point of between 400 to 540.degree. C.,
preferably between 420 to 485.degree. C., more preferably between
425 to 483.degree. C. and most preferably between 458 to
483.degree. C.
[0022] The Fischer-Tropsch product is known in the art. By the term
"Fischer-Tropsch product" is meant a synthesis product of a
Fischer-Tropsch process. In a Fischer-Tropsch process synthesis gas
is converted to a synthesis product. Synthesis gas or syngas is a
mixture of hydrogen and carbon monoxide that is obtained by
conversion of a hydrocarbonaceous feedstock. Suitable feedstock
include natural gas, crude oil, heavy oil fractions, coal, biomass
and lignite. A Fischer-Tropsch product may also be referred to a
GTL (Gas-to-Liquids) product.
[0023] The preparation of a Fischer-Tropsch product has been
described in e.g. WO2003/070857.
[0024] The Fischer-Tropsch product of the Fischer-Tropsch process
is usually separated into a water stream, a gaseous stream
comprising unconverted synthesis gas, carbon dioxide, inert gases
and C1 to C2, and a C3+ product stream by distillation.
Commercially available equipment can be used. The distillation may
be carried out at atmospheric pressure, but also reduced pressure
may be used. By Fischer-Tropsch product in the present invention is
meant the C3+ product stream.
[0025] In step (b) a paraffinic hydrocarbon feedstock stream
provided in step(a) is subjected to a
hydrocracking/hydroisomerization step to obtain an at least
partially isomerised product stream.
[0026] It has been found that the amount of the isomerised product
is dependent on the hydrocracking/hydroisomerization conditions.
Hydrocracking/hydroisomerization processes are known in the art and
therefore not discussed here in detail.
[0027] Hydrocracking/hydroisomerization and the effect of
hydrocracking/hydroisomerization conditions on the amount of
isomerised product are for example described in Chapter 6 of
"Hydrocracking Science and Technology", Julius Scherzer; A. J.
Cruia, Marcel Dekker, Inc, New York, 1996, ISBN 0-8247-9760-4.
[0028] The preparation of an at least partially Fischer-Tropsch
derived isomerised feedstock in step (b) has been described in e.g.
WO 2009/080681. The preparation of an at least partially mineral
derived isomerised feedstock in step (b) has been described in e.g.
EP-A-0400742.
[0029] In step (c) the product stream of step (b) is separated to
obtain a lower boiling fraction and a higher boiling fraction.
[0030] Preferably, the lower boiling fraction of step (c) boils in
a temperature range of from 350 to 500.degree. C. and the higher
boiling fraction of step (c) boils in a temperature range of from
425 to 600.degree. C.
[0031] By boiling points at atmospheric conditions is meant
atmospheric boiling points, which boiling points can be determined
using methods such as ASTM D2887 or ASTM D7169.
[0032] The separation is preferably performed by means of a high
vacuum distillation.
[0033] The lower boiling fraction of step (c) preferably comprises
a C.sub.20 to C.sub.30 fraction, more preferably comprising a
C.sub.20 to C.sub.23 fraction.
[0034] The higher boiling fraction of step (c) preferably comprises
a C.sub.30 to C.sub.40 fraction, more preferably comprising a
C.sub.23 to C.sub.40 fraction.
[0035] In step (d) the lower boiling fraction of step (c) is
dewaxed to obtain a light base oil.
[0036] In a further aspect the present invention provides a light
base oil obtainable by the process according to the present
invention.
[0037] The light base oil may be characterized by one or more of
the features described herein below, with no additional limiting
technical meaning being attributed to the label "light".
[0038] Typically dewaxing processes are catalytic dewaxing and
solvent dewaxing. Catalytic and solvent dewaxing processes are
known in the art and therefore not described here in detail.
Typical catalytic and solvent dewaxing processes are for example
described in Chapter 7 and 8 of "Lubricant base oil and wax
processing", Avilino Sequeira, Jr., Marcel Dekker, Inc, New York,
1994, ISBN 0-8247-9256-4.
[0039] Dewaxing of the low boiling fraction in step (d) is
preferably performed by means of a catalytic dewaxing process.
[0040] Typical catalytic dewaxing processes are for example
described in WO 2009/080681 and WO2012055755.
[0041] Suitably, catalytic dewaxing is performed in the presence of
a catalyst comprising a molecular sieve and a group VIII metal.
[0042] Suitable dewaxing catalyst are heterogeneous catalysts
comprising molecular sieve, more suitably intermediate pore size
zeolites and optionally in combination a metal having a
hydrogenation function, such as the Group VIII metals. Preferably,
the intermediate pore size zeolites have a pore diameter of between
0.35 and 0.8 nm.
[0043] Preferably, catalytic dewaxing is performed in the presence
of a catalyst comprising a molecular sieve and a group VIII metal,
wherein the molecular sieve is selected from a group consisting of
a MTW, MTT, TON type molecular sieve, ZSM-12, ZSM-48 and EU-2.
[0044] In the present invention, the reference to ZSM-48 and EU-2
is used to indicate that all zeolites can be used that belong to
the ZSM-48 family of disordered structures also referred to as the
*MRE family and described in the Catalog of Disorder in Zeolite
Frameworks published in 2000 on behalf of the Structure Commission
of the International Zeolite Assocation. Even if EU-2 would be
considered to be different from ZSM-48, both ZSM-48 and EU-2 can be
used in the present invention. Zeolites ZBM-30 and EU-11 resemble
ZSM-48 closely and also are considered to be members of the
zeolites whose structure belongs to the ZSM-48 family. In the
present application, any reference to ZSM-48 zeolite also is a
reference to ZBM-30 and EU-11 zeolite.
[0045] Besides ZSM-48 and/or EU-2 zeolite, further zeolites can be
present in the catalyst composition especially if it is desired to
modify its catalytic properties. It has been found that it can be
advantageous to have present zeolite ZSM-12 which zeolite has been
defined in the Database of Zeolite Structures published in
2007/2008 on behalf of the Structure Commission of the
International Zeolite Assocation.
[0046] Suitable Group VIII metals are nickel, cobalt, platinum and
palladium. Preferably, a Group VIII metal is platinum or
palladium.
[0047] The dewaxing catalyst suitably also comprises a binder. The
binder can be non-acidic. Examples of suitable binders are clay,
silica, titania, zirconia, alumina, mixtures and combinations of
the above and other binders known to one skilled in the art.
[0048] Preferably the catalyst comprises a silica or a titania
binder.
[0049] The catalytically dewaxed light base oil in step (d)
preferably has a cloud point according to ASTM D-2500 of below
-15.degree. C., more preferably below -20.degree. C., more
preferably below -28.degree. C., more preferably below -32.degree.
C. and most preferably below -40.degree. C.
[0050] The kinematic viscosity of the catalytically dewaxed light
base oil in step (d) at 100.degree. C. according to ASTM D-445 is
preferably from 2.5 to 6.0 mm.sup.2/s, more preferably from 3.0 to
5.0 mm.sup.2/s, more preferably from 3.5 to 4.5 mm.sup.2/s, and
most preferably from 3.8 to 4.2 mm.sup.2/s.
[0051] The pour point of the light base oil according to ASTM D5950
is preferably of below 0.degree. C., more preferably below
-5.degree. C., more preferably below -15.degree. C., more
preferably below -20.degree. C., and most preferably below
-25.degree. C. and preferably for at most above -48.degree..
[0052] In step (e) the higher boiling fraction of step (c) is
dewaxed to obtain a heavy base oil.
[0053] Preferred dewaxing conditions step are described above.
[0054] Preferably, catalytic dewaxing of the lower boiling fraction
of step (c) to obtain a light base oil and catalytic dewaxing of
the higher boiling fraction of step (c) occurs simultaneously but
separately. Thus, suitably, step (d) and (e) of the present
invention occurs simultaneously.
[0055] In another aspect the present invention provides a heavy
base oil obtainable by the process according to the present
invention. The heavy base oil may be characterised by one or more
of the features described herein below, with no additional limiting
technical meaning being attributed to the label "heavy".
[0056] The catalytically dewaxed heavy base oil in step (e)
preferably has a cloud point according to ASTM D-2500 of below
-10.degree. C., preferably below -15.degree. C., more preferably
below -18.degree. C. and most preferably below -20.degree. C.
[0057] The kinematic viscosity of the catalytically dewaxed heavy
base oil in step (e) at 100.degree. C. according to ASTM D-445 is
preferably from 5.0 to 12.0 mm.sup.2/s, more preferably from 6.0 to
10.0 mm.sup.2/s, more preferably from 7.0 to 9.0 mm.sup.2/s, and
most preferably from 7.5 to 8.5 mm.sup.2/s.
[0058] The pour point of the catalytically dewaxed heavy base oil
according to ASTM D5950 is preferably of below -5.degree. C., more
preferably below -10.degree. C., more preferably below -15.degree.
C., more preferably below -20.degree. C., and most preferably below
-25.degree. C. and preferably for at most above -48.degree..
[0059] Suitably, the light and heavy base oils according to the
present invention are Group II mineral base oils, Group III mineral
base oils, and Group III Fischer-Tropsch derived base oils
according to the definitions of American Petroleum Institute (API)
for category II and III. These API categories are defined in API
Publication 1509, 15.sup.th Edition, Appendix E, April 2002.
[0060] In another aspect the process according to the present
invention comprises a further step (f) wherein the light base oil
of step (d) and the heavy base oil of step (e) are each separated
by vacuum distillation to remove light ends and obtain a first
light base oil and a first heavy base oil and light ends. Typically
light ends are compounds such as methane, ethane and propane, which
light ends in this present invention are obtained from cracking in
the catalytic dewaxing steps (d) and (e).
[0061] The difference between the cloud point and the pour point of
the catalytically dewaxed light base oil of step (d) and of the
heavy base oil of step (e) is less than 6.degree. C., preferably
less than 3.degree. C., and more preferably less than 2.degree.
C.
[0062] FIG. 1 schematically shows a process scheme of the process
scheme of a preferred embodiment of the process according to the
present invention.
[0063] For the purpose of this description, a single reference
number will be assigned to a line as well as a stream carried in
that line.
[0064] The process scheme is generally referred to with reference
numeral 1.
[0065] In a paraffin hydrocarbon process reactor 2a a paraffin
product stream 10a is obtained. This product is fed to a
hydrocracking/hydroisomerization reactor 3a wherein the paraffinic
product stream 10a is converted to an at least partially isomerised
product stream 20a. This isomerised product stream 20a is distilled
in a distillation column 4a to recover a lower boiling fraction 30a
and a higher boiling fraction 30b.
[0066] The lower boiling fraction 30a of distillation column 4a is
fed to a catalytic dewaxing reactor 5a to obtain a light base oil
40a. The effluent 40a of reactor 5a is distilled in a distillation
column 6a to recover further base oils 50a with different kinematic
viscosities at 100.degree. C. from 2.5 to 6.0 mm.sup.2/s,
preferably from 3.0 to 5.0 mm.sup.2/s, more preferably from 3.5 to
4.5 mm.sup.2/s, and most preferably from 3.8 to 4.2 mm.sup.2/s.
[0067] Simultaneously to the preparation of light base oil 40a as
described above, a heavy base oil 40b is prepared.
[0068] The higher boiling fraction 30b of distillation column 4a is
fed to a catalytic dewaxing reactor 5b to obtain a heavy base oil
40b. The effluent 40b of reactor 6b is distilled in a distillation
column 6b to recover further base oils 50b with different kinematic
viscosities at 100.degree. C. from 5.0 to 12.0 mm.sup.2/s,
preferably from 6.0 to 10.0 mm.sup.2/s, more preferably from 7.0 to
9.0 mm.sup.2/s, and most preferably from 7.5 to 8.5 mm.sup.2/s.
[0069] The present invention is described below with reference to
the following Examples, which are not intended to limit the scope
of the present invention in any way.
EXAMPLE 1
[0070] Preparation of Catalytically Dewaxed API GP II Base Oils
[0071] The GPII Base oils were derived from a hydrowax feedstock
(also known as fuel hydrocracker bottoms). This hydrowax feedstock
was obtained from Shell Pernis refinery (Pernis, Netherlands)
[0072] The properties of the hydrowax feedstock are listed in Table
1.
TABLE-US-00001 TABLE 1 Hydrowax feedstock Initial boiling point
360.degree. C. Final boiling point 483.degree. C.
[0073] The hydrowax feedstock was continuously fed to a
hydrocracking step. In the hydrocracking step the fraction was
contacted with a hydrocracking catalyst of Example 1 of
EP-A-532118. The conditions in the hydrocracking step (a) were: a
fresh feed Weight Hourly Space Velocity (WHSV) of 0.6 kg/lh,
recycle feed WHSV of 0.17 kg/lh, hydrogen gas rate=750 Nl/kg, total
pressure=77 bar, and a reactor temperature of 334.degree. C.
[0074] The effluent of the hydrocracking step (isomerised product)
was continuously distilled under vacuum to give four fractions (see
Table 2: Experiments A, B, C and D).
[0075] In the dewaxing step, the four fractions described above
were contacted with a dealuminated silica bound ZSM-5 catalyst
comprising 0.7% by weight Pt and 30 wt. % ZSM-5 as described in
Example of WO-A-0029511. The dewaxing conditions were 40 bar
hydrogen, WHSV=1 kg/l/h and a temperature of 355.degree. C. The
properties of the obtained catalytic dewaxed base oils are listed
in Table 3.
TABLE-US-00002 TABLE 2 Feed to catalytic dewaxing Exper- Exper-
Exper- Exper- Wt. % iment iment iment iment recovered at A B C D
IBP 228 322 421 470+ 5% 268 392 429 10% 290 398 434 30% 342 410 447
50% 367 419 456 70% 383 427 464 90% 398 437 472 95% 404 442 475 99%
418 453 480 FBP 425 458 483
TABLE-US-00003 TABLE 3 Properties of catalytic Exper- Exper- Exper-
Exper- dewaxed base iment iment iment iment oils A B C D Kinematic
4.104 8.603 12.94 13.01 viscosity at 100.degree. C. according to
ASTM D-445 [cSt] Kinematic 19.71 63.05 120.9 119.6 viscosity at
40.degree. C. according to ASTM D-445 [cSt] VI 108 108 100 102
according to ASTM D-2270 Pour point -15 -15 -12 -9 according to
ASTM D-5950 (.degree. C.) Cloud point -11 -13 -10 -4 according to
ASTM D-2500 (.degree. C.) Cloud/pour 4 2 2 5 point differential
(.degree. C.) Content of 1.1 1.6 9.0 3.0 aromatics according to IP
368 [wt. %] Content of <5 6 31 20 sulphur according to ASTM
D-2622- 98 [ppm] Visual Clear and Clear and Clear and Clear and
Appearance bright bright bright bright
COMPARATIVE EXAMPLE A
[0076] The procedure of Example 1 was repeated, with the proviso
that the isomerised product was catalytic dewaxed in one and the
same device prior to distillation into several base oils.
[0077] The isomerised product was catalytically dewaxed as
described above in Example 1 to obtain a catalytically dewaxed
mineral derived base oil.
[0078] The obtained catalytically dewaxed mineral derived base oil
was distilled into four base oil fractions.
[0079] The properties of these four base oils are listed in Table
4.
TABLE-US-00004 TABLE 4 Properties of catalytic Exper- Exper- Exper-
Exper- dewaxed base iment iment iment iment oils E F G H Kinematic
2.143 4.735 6.452 11.42 viscosity at 100.degree. C. according to
ASTM D-445 [cSt] Kinematic 7.086 25.07 40.21 93.64 viscosity at
40.degree. C. according to ASTM D-445 [cSt] VI 102 107 111 110
according to ASTM D-2270 Pour point -33 -21 -15 -9 according to
ASTM D-5950 (.degree. C.) Cloud point -30 -14 -6 -2 according to
ASTM D-2500 (.degree. C.) Cloud/pour 3 7 9 7 point differential
(.degree. C.) Content of 0.7 1.3 1.2 1.8 aromatics according to IP
368 [wt. %] Content of 76 68 73 105 sulphur according to ASTM
D-2622- 98 [ppm] Visual Clear and Clear and Clear and Clear and
Appearance bright bright bright bright
[0080] FIG. 2 shows a simple comparison between the cloud
point/pour point differentials of the GP II base oils with several
viscosities obtained according the present invention (Example 1)
and the cloud point/pour point differentials of base oils with
several viscosities obtained when the isomerised product was
catalytic dewaxed in one and the same device prior to separation of
this isomerised product into fractions with different boiling
ranges (Comparative Example A).
[0081] Discussion
[0082] The results in Table 4 (Example 1) show that the process
according to the present invention resulted in several clear and
bright GP II base oils having low cloud point/pour point
differentials. This indicates that the microcrystalline particles
can be easy separated from the obtained base oils or in other words
poor isomerisation of the heavier waxes in the obtained base oils.
When compared with Comparative Example A (see FIG. 2) wherein the
feedstock was catalytic dewaxed but without prior separation of the
feedstock into fractions with different boiling ranges, catalytic
dewaxing followed by separation into several GP II base oils
resulted in GP II base oils with high cloud point/pour point
* * * * *