U.S. patent application number 10/561588 was filed with the patent office on 2007-11-29 for process to prepare a lubricating base oil.
Invention is credited to Gilbert Robert Bernard Germaine, Wiecher Derk Evert Steenge.
Application Number | 20070272592 10/561588 |
Document ID | / |
Family ID | 33547793 |
Filed Date | 2007-11-29 |
United States Patent
Application |
20070272592 |
Kind Code |
A1 |
Germaine; Gilbert Robert Bernard ;
et al. |
November 29, 2007 |
Process to Prepare a Lubricating Base Oil
Abstract
Process to prepare a base oil having an paraffin content of
between 75 and 95 wt % by subjecting a mixture of a Fischer-Tropsch
derived feed and a petroleum derived feed to a catalytic pour point
reducing treatment.
Inventors: |
Germaine; Gilbert Robert
Bernard; (Petit Couronne, FR) ; Steenge; Wiecher Derk
Evert; (Amsterdam, NL) |
Correspondence
Address: |
SHELL OIL COMPANY
P O BOX 2463
HOUSTON
TX
772522463
US
|
Family ID: |
33547793 |
Appl. No.: |
10/561588 |
Filed: |
June 25, 2004 |
PCT Filed: |
June 25, 2004 |
PCT NO: |
PCT/EP04/51248 |
371 Date: |
March 16, 2007 |
Current U.S.
Class: |
208/110 ;
208/108 |
Current CPC
Class: |
C10G 45/58 20130101;
C10G 65/12 20130101 |
Class at
Publication: |
208/110 ;
208/108 |
International
Class: |
C10G 73/02 20060101
C10G073/02; C10G 65/12 20060101 C10G065/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 27, 2003 |
EP |
03291598.5 |
Claims
1. A process to prepare a base oil having a paraffin content of
between 75 and 95 wt % the process comprising subjecting a mixture
of a hydroisomerized Fischer-Tropsch wax and a petroleum derived
feed to a catalytic pour point reducing treatment, wherein the
petroleum derived feed has an aromatic content of between 0 and 20
wt % and a naphthenic compound content of between 15 and 90 wt %
and wherein the fraction of petroleum derived feed in the mixture
is higher than 5 wt % and lower than 50 wt %.
2. The process of claim 1, wherein the petroleum derived feed is a
bottoms fraction of a fuels hydrocracker.
3. The process of Process according to claim 2, wherein the content
of sulfur in the mixed feed to the pour point reducing treatment is
below 50 ppm and the content of nitrogen in the mixed feed to the
pour point reducing treatment is below 10 ppm.
4. The process of claim 1, wherein the wax content in the petroleum
derived feed is below 30 wt %.
5. The process of claim 4, wherein the pour point of the petroleum
derived feed is below -10.degree. C.
6. The process of claim 1, wherein the petroleum derived feed has a
saturates content of greater than 98 wt % a viscosity index of
between 80 and 150 and a sulfur content of below 0.001 wt %.
7. The process of claim 6, wherein the petroleum derived feed has
been obtained in a process comprising a hydrofinishing step
performed at a hydrogen pressure of greater than 100 bars.
8. The process of claim 1, wherein the base oil is hydrogenated
after performing the pour point reducing treatment such that the
content of aromatics is below 1 wt %.
9. The process of claim 1, wherein the catalytic pour point
reducing treatment is a catalytic dewaxing process performed in the
presence of a catalyst comprising a Group VIII metal and an
intermediate pore size zeolite having pore diameter between 0.35
and 0.8 nm, and a binder.
10. The process of claim 1, wherein after performing the catalytic
pour point reducing treatment hydrogen is separated from the
dewaxed effluent, contacted with a heterogeneous adsorbent
selective for removing hydrogen sulfide and recycled to said
catalytic pour point reducing treatment.
11. The process of claim 10, wherein the heterogeneous adsorbent is
zinc oxide.
12. The process of claim 1, wherein the hydroisomerized
Fischer-Tropsch wax is obtained by a process comprising: (a)
hydrocracking/hydroisomerizing a Fischer-Tropsch product, and, (b)
distilling the product of step (a) into one or more gas oil
fractions and a higher boiling Fischer-Tropsch derived feed.
13. The process of claim 12, wherein the Fischer-Tropsch product
used as feed in step (a) is a product wherein the weight ratio of
compounds having at least 60 or more carbon atoms and compounds
having at least 30 carbon atoms in the Fischer-Tropsch product is
at least 0.4 and wherein at least 30 wt % of compounds in the
Fischer-Tropsch product have at least 30 carbon atoms.
14. The process of claim 2, wherein the content of sulfur in the
mixed feed to the pour point reducing treatment is below 50 ppm and
the content of nitrogen in the mixed feed to the pour point
reducing treatment is below 10 ppm.
15. The process of claim 2, wherein the wax content in the
petroleum derived feed is below 30 wt %.
16. The process of claim 15, wherein the pour point of the
petroleum derived feed is below -10.degree. C.
17. The process of claim 2, wherein the petroleum derived feed has
a saturates content of greater than 98 wt % a viscosity index of
between 80 and 150 and a sulfur content of below 0.001 wt %.
18. The process of claim 17, wherein the petroleum derived feed has
been obtained in a process comprising a hydrofinishing step
performed at a hydrogen pressure of greater than 100 bars.
19. The process of claim 2, wherein the base oil is hydrogenated
after performing the pour point reducing treatment such that the
content of aromatics is below 1 wt %.
20. The process of claim 2, wherein the catalytic pour point
reducing treatment is a catalytic dewaxing process performed in the
presence of a catalyst comprising a Group VIII metal and an
intermediate pore size zeolite having pore diameter between 0.35
and 0.8 nm, and a binder.
21. The process of claim 2, wherein after performing the catalytic
pour point reducing treatment hydrogen is separated from the
dewaxed effluent, contacted with a heterogeneous adsorbent
selective for removing hydrogen sulfide and recycled to said
catalytic pour point reducing treatment.
22. The process of claim 21, wherein the heterogeneous adsorbent is
zinc oxide.
23. The process of claim 2, wherein the hydroisomerized
Fischer-Tropsch wax is obtained by a process comprising: (a)
hydrocracking/hydroisomerizing a Fischer-Tropsch product, and, (b)
distilling the product of step (a) into one or more gas oil
fractions and a higher boiling Fischer-Tropsch derived feed.
24. The process of claim 23, wherein the Fischer-Tropsch product
used as feed in step (a) is a product wherein the weight ratio of
compounds having at least 60 or more carbon atoms and compounds
having at least 30 carbon atoms in the Fischer-Tropsch product is
at least 0.4 and wherein at least 30 wt % of compounds in the
Fischer-Tropsch product have at least 30 carbon atoms.
Description
[0001] The invention is directed to a process to prepare a base oil
having an paraffin content of between 75 and 95 wt %.
[0002] WO-A-0157166 describes the use of a highly paraffinic base
oil as obtained from a Fischer-Tropsch wax in a motor engine
lubricant formulation. The examples illustrate that such
formulations will also consist of an ester, which according to the
description of the patent are added to confer additional desired
characteristics, such as additive solvency.
[0003] The use of ester co-base fluids in lubricant formulations as
illustrated in WO-A-0157166 is not desired because such ester
co-base fluids are not widely available and thus expensive.
Additive solvency may be improved by using a paraffinic base stock,
which contains less paraffins. Such base oils may be prepared by
hydroisomerisation of petroleum derived waxes followed by a solvent
or catalytic dewaxing step. A disadvantage of such a process is
that the starting petroleum derived waxes, such as for example
slack wax, are not easily obtainable. Furthermore such waxes may
not always have the desired high paraffin content needed to make
the desired base oils as per this invention.
[0004] The object of the present invention is to provide a process
wherein a base oil with a paraffin content of between 75 and 95 wt
% is obtained which does not have the disadvantages of the prior
art processes.
[0005] This object is achieved by the following process. Process to
prepare a base oil having an paraffin content of between 75 and 95
wt % by subjecting a mixture of a Fischer-Tropsch derived feed and
a petroleum derived feed to a catalytic pour point reducing
treatment.
[0006] Applicants found that by mixing a relatively small amount of
a petroleum derived feed with a Fischer-Tropsch derived feed before
performing a catalytic pour point reducing treatment a base oil may
be obtained having the desired properties.
[0007] The petroleum-derived fraction may in principle be any
fraction boiling in the base oil range and containing
non-paraffinic compounds. Preferably a petroleum-derived fraction
is used which has been subjected to a hydroprocessing step in order
to reduce aromatic, sulphur and nitrogen content of such fractions
and improve some of the desired properties such viscosity index.
The hydroprocessing step may be a hydrotreating optionally followed
by a hydrocracking step. Such processes are for example performed
when preparing base oils from a petroleum derived vacuum distillate
or de-asphalted oils.
[0008] A very interesting petroleum derived feed is the bottoms
fraction of a fuels hydrocracker. With a fuels hydrocracker in the
context of the present invention is meant a hydrocracker process
which main products are naphtha, kerosene and gas oil. The
conversion, expressed in the weight percentage of the fraction in
the feed to the hydrotreater-hydrocracker which boils above
370.degree. C. which are converted to products boiling below
370.degree. C., in the hydrotreater-hydrocracker process is
typically above 50 wt %. Examples of possible fuels hydrocracker
processes, which may yield a bottoms fraction which can be used in
the present process, are described in the above referred to
EP-A-699225, EP-A-649896, WO-A-9718278, EP-A-705321, EP-A-994173
and U.S. Pat. No. 4,851,109.
[0009] Another interesting petroleum derived feed is the fraction
obtained in a dedicated base oil hydrotreater-hydrocracker. In such
a hydrotreater-hydrocracker the main products will boil in the base
oil range. Typically such processes operate at a feed conversion of
below 50 wt % and more typically between 20 and 40 wt %. The
petroleum derived feed is thus the high boiling fraction as
obtained in such a process prior to dewaxing.
[0010] Preferably the fuels hydrocracker is operated in two steps,
consisting of a preliminary hydrotreating step followed by a
hydrocracking step. In the hydrotreating step nitrogen and sulphur
are removed and aromatics are saturated to naphthenes
[0011] The Fischer-Tropsch derived feed preferably is a
hydroisomerized Fischer-Tropsch wax. Such a feed may be obtained by
well-known processes, for example the so-called commercial Sasol
process, the Shell Middle Distillate Process or by the
non-commercial Exxon process. These and other processes are for
example described in more detail in EP-A-776959, EP-A-668342, U.S.
Pat. No. 4,943,672, U.S. Pat. No. 5,059,299, WO-A-9934917 and
WO-A-9920720. The process will generally comprise a Fischer-Tropsch
synthesis and a hydroisomerisation step as described in these
publications.
[0012] The mixture of petroleum derived and Fischer-Tropsch derived
feeds will suitably have a viscosity corresponding to the desired
viscosity of the base oil product. Preferably the kinematic
viscosity at 100.degree. C. of the mixture is between 3 and 10 cSt.
Suitable distillate fractions obtained in step (a) have a T10 wt %
boiling point of between 200 and 450.degree. C. and a T90 wt %
boiling point of between 300 and 550.degree. C. The fraction of
petroleum derived feed in the mixture is preferably higher than 5
wt %, more preferably higher than 10 wt % and preferably lower than
50 wt % and more preferably below 30 wt % and even more preferably
below 25 wt %. The actual content of petroleum-derived feed in the
mixture will of course depend on the paraffin content of said feed.
The mixture will preferably contain less than 50 ppm sulphur and/or
less that 10 ppm nitrogen.
[0013] With the catalytic pour point reducing treatment is
understood every process wherein the pour point of the base oil is
reduced by more than 10.degree. C., preferably more than 20.degree.
C., more preferably more than 25.degree. C.
[0014] The catalytic dewaxing or pour point reducing process can be
performed by any process wherein in the presence of a catalyst and
hydrogen the pour point of the base oil precursor fraction is
reduced as specified above. Suitable dewaxing catalysts are
heterogeneous catalysts comprising a molecular sieve and optionally
in combination with a metal having a hydrogenation function, such
as the Group VIII metals. Molecular sieves, and more suitably
intermediate pore size zeolites, have shown a good catalytic
ability to reduce the pour point of the distillate base oil
precursor fraction under catalytic dewaxing conditions. Preferably
the intermediate pore size zeolites have a pore diameter of between
0.35 and 0.8 nm. Suitable intermediate pore size zeolites are
mordenite, ZSM-5, ZSM-12, ZSM-22, ZSM-23, SSZ-32, ZSM-35 and
ZSM-48. Another preferred group of molecular sieves are the
silica-aluminaphosphate (SAPO) materials of which SAPO-11 is most
preferred as for example described in U.S. Pat. No. 4,859,311.
ZSM-5 may optionally be used in its HZSM-5 form in the absence of
any Group VIII metal. The other molecular sieves are preferably
used in combination with an added Group VIII metal. Suitable Group
VIII metals are nickel, cobalt, platinum and palladium. Examples of
possible combinations are Ni/ZSM-5, Pt/ZSM-23, Pd/ZSM-23, Pt/ZSM-48
and Pt/SAPO-11. Further details and examples of suitable molecular
sieves and dewaxing conditions are for example described in
WO-A-9718278, U.S. Pat. No. 5,053,373, U.S. Pat. No. 5,252,527 and
U.S. Pat. No. 4,574,043.
[0015] The dewaxing catalyst suitably also comprises a binder. The
binder can be a synthetic or naturally occurring (inorganic)
substance, for example clay, silica and/or metal oxides. Natural
occurring clays are for example of the montmorillonite and kaolin
families. The binder is preferably a porous binder material, for
example a refractory oxide of which examples are: alumina,
silica-alumina, silica-magnesia, silica-zirconia, silica-thoria,
silica-beryllia, silica-titania as well as ternary compositions for
example silica-alumina-thoria, silica-alumina-zirconia,
silica-alumina-magnesia and silica-magnesia-zirconia. More
preferably a low acidity refractory oxide binder material which is
essentially free of alumina is used. Examples of these binder
materials are silica, zirconia, titanium dioxide, germanium
dioxide, boria and mixtures of two or more of these of which
examples are listed above. The most preferred binder is silica.
[0016] A preferred class of dewaxing catalysts comprise
intermediate zeolite crystallites as described above and a low
acidity refractory oxide binder material which is essentially free
of alumina as described above, wherein the surface of the
aluminosilicate zeolite crystallites has been modified by
subjecting the aluminosilicate zeolite crystallites to a surface
dealumination treatment. A preferred dealumination treatment is by
contacting an extrudate of the binder and the zeolite with an
aqueous solution of a fluorosilicate salt as described in for
example U.S. Pat. No. 5,157,191 or WO-A-2000029511. Examples of
suitable dewaxing catalysts as described above are silica bound and
dealuminated Pt/ZSM-5, silica bound and dealuminated Pt/ZSM-23,
silica bound and dealuminated Pt/ZSM-12, silica bound and
dealuminated Pt/ZSM-22 as for example described in WO-A-200029511
and EP-B-832171.
[0017] Catalytic dewaxing conditions are known in the art and
typically involve operating temperatures in the range of from 200
to 500.degree. C., suitably from 250 to 400.degree. C., hydrogen
pressures in the range of from 10 to 200 bar, preferably from 40 to
70 bar, weight hourly space velocities (WHSV) in the range of from
0.1 to 10 kg of oil per litre of catalyst per hour (kg/l/hr),
suitably from 0.2 to 5 kg/l/hr, more suitably from 0.5 to 3 kg/l/hr
and hydrogen to oil ratios in the range of from 100 to 2,000 litres
of hydrogen per litre of oil. By varying the temperature between
315 and 375.degree. C. at between 40-70 bars, in the catalytic
dewaxing step it is possible to prepare base oils having different
pour point specifications varying from suitably lower than -60 to
-10.degree. C.
[0018] After performing the pour point reducing treatment lower
boiling compounds formed during said treatment are suitably
removed, preferably by means of distillation, optionally in
combination with an initial flashing step.
[0019] The effluent of the pour point reducing treatment may
suitably be subjected to a hydrogenation treatment. Hydrogenation
may be performed on the entire effluent or on specific base oil
grades after the above described fractionation. This may be
required in order to reduce the content of aromatic compounds in
the reduced pour point product to preferably values of below 1 wt
%. Such a hydrogenation is also referred to as a hydrofinishing
step. This step is suitably carried out at a temperature between
180 and 380.degree. C., a total pressure of between 10 to 250 bar
and preferably above 100 bar and more preferably between 120 and
250 bar. The WHSV (Weight hourly space velocity) ranges from 0.3 to
2 kg of oil per litre of catalyst per hour (kg/lh). Preferably a
hydrogenation is performed in the same reactor as the catalytic
dewaxing reactor. In such a reactor the beds of dewaxing catalyst
and hydrogenation catalyst will be placed in a stacked bed on top
of each other.
[0020] The hydrogenation catalyst is suitably a supported catalyst
comprising a dispersed Group VIII metal. Possible Group VIII metals
are cobalt, nickel, palladium and platinum. Cobalt and nickel
containing catalysts may also comprise a Group VIB metal, suitably
molybdenum and tungsten. Suitable carrier or support materials are
low acidity amorphous refractory oxides. Examples of suitable
amorphous refractory oxides include inorganic oxides, such as
alumina, silica, titania, zirconia, boria, silica-alumina,
fluorided alumina, fluorided silica-alumina and mixtures of two or
more of these.
[0021] Examples of suitable hydrogenation catalysts are
nickel-molybdenum containing catalyst such as KF-847 and KF-8010
(AKZO Nobel) M-8-24 and M-8-25 (BASF), and C-424, DN-190, HDS-3 and
HDS-4 (Criterion); nickel-tungsten containing catalysts such as
NI-4342 and NI-4352 (Engelhard) and C-454 (Criterion);
cobalt-molybdenum containing catalysts such as KF-330 (AKZO-Nobel),
HDS-22 (Criterion) and HPC-601 (Engelhard). Preferably platinum
containing and more preferably platinum and palladium containing
catalysts are used. Preferred supports for these palladium and/or
platinum containing catalysts are amorphous silica-alumina.
Examples of suitable silica-alumina carriers are disclosed in
WO-A-9410263. A preferred catalyst comprises an alloy of palladium
and platinum preferably supported on an amorphous silica-alumina
carrier of which the commercially available catalyst C-624 of
Criterion Catalyst Company (Houston, Tex.) is an example.
[0022] From the effluent of the pour point reducing treatment and
the optional hydrogenation treatment one or more base oil grades
may be isolated by means of fractionation. Base oil products having
kinematic viscosity at 100.degree. C. of between 2 and 10 cSt,
having a volatility of between 8 and 11% (according to CEC L40 T87)
and a pour point of between -20 and -60.degree. C. (according to
ASTM D 97) may advantageously be obtained.
[0023] The content of paraffins is more preferably less than 90 wt
% and more preferably higher than 80 wt %.
[0024] The above-described base oil can suitably find use as base
oil for an Automatic Transmission Fluids (ATF), motor engine oils,
electrical oils or transformer oils and refrigerator oils.
lubricant formulations such as motor engine oils of the 0W-x and
5W-x specification according to the SAE J-300 viscosity
classification, wherein x is 20, 30, 40, 50 or 60 may be
advantageously made using this base oil.
[0025] It has been found that lubricant formulations can be
prepared with the base oils obtainable by the process of the
current invention without the need to add high contents of
additional ester or aromatic co-base oils. Preferably less than 15
wt % and more preferably less than 10 wt % of such ester or
aromatic co-base oil is present in such formulations.
* * * * *