U.S. patent application number 10/519250 was filed with the patent office on 2005-11-24 for process to prepare medicinal and technical white oils.
Invention is credited to Germaine, Gilbert Robert Bernard.
Application Number | 20050258074 10/519250 |
Document ID | / |
Family ID | 29797324 |
Filed Date | 2005-11-24 |
United States Patent
Application |
20050258074 |
Kind Code |
A1 |
Germaine, Gilbert Robert
Bernard |
November 24, 2005 |
Process to prepare medicinal and technical white oils
Abstract
A process for the preparation of medicinal white oil or a
technical white oil from a Fischer-Tropsch derived paraffinic
distillate bottom product, wherein the bottom product is contacted
with a heterogeneous adsorbent.
Inventors: |
Germaine, Gilbert Robert
Bernard; (Petit Couronne, FR) |
Correspondence
Address: |
Jennifer D Adamson
Shell Oil Company
Intellectual Property
PO Box 2463
Houston
TX
77252-2463
US
|
Family ID: |
29797324 |
Appl. No.: |
10/519250 |
Filed: |
December 22, 2004 |
PCT Filed: |
May 7, 2003 |
PCT NO: |
PCT/EP03/04853 |
Current U.S.
Class: |
208/99 ; 208/14;
208/299; 208/307 |
Current CPC
Class: |
C10G 2400/14 20130101;
C10G 25/00 20130101 |
Class at
Publication: |
208/099 ;
208/014; 208/299; 208/307 |
International
Class: |
C10G 067/06; C10G
025/00; C10M 011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 24, 2002 |
EP |
02291563.1 |
Claims
1. A process for the preparation of medicinal white oil or a
technical white oil from a Fischer-Tropsch derived paraffinic
distillate bottom product, comprising contacting the bottom product
with a heterogeneous adsorbent.
2. The process of to claim 1, wherein the adsorbent comprises
active carbon.
3. The process of claims 1, wherein a medicinal white oil is
obtained having a kinematic viscosity at 100.degree. C. of more
than 8.5 cSt, a non-cyclic isoparaffins content of between 80 and
98 wt %, a Saybolt color of greater than +30, Ultra violet
adsorption spectra values as measured by ASTM D 2269 of less than
0.70 in the 280-289 nm spectral band, of less than 0.60 in the
290-299 nm spectral band, of less than 0.40 in the 300-329 nm
spectral band and of less than 0.09 in the 330-380 nm spectral band
as according to FDA 178 3620 ('c).
4. The process of claim 1, wherein said bottom product is obtained
by a process comprising: (a) hydrocracking/hydroisomerisating a
Fischer-Tropsch derived feed, wherein weight ratio of compounds
having at least 60 or more carbon atoms and compounds having at
least 30 carbon atoms in the Fischer-Tropsch derived feed is at
least 0.2 and wherein at least 30 wt % of compounds in the
Fischer-Tropsch derived feed have at least 30 carbon atoms; (b)
separating the product of step (a) into one or more distillate
fraction(s) of lower boiling fractions and a broad range base oil
precursor fraction and a heavy fraction such that the T90 wt %
boiling point of the base oil precursor fraction is between 350 and
550.degree. C.; (c) performing a pour point reducing step to the
broad range base oil precursor fraction obtained in step (b); and,
(d) isolating a heavy bottom distillate fraction by distilling the
product of step (c).
5. A Fischer-Tropsch derived medicinal white oil having a kinematic
viscosity at 100.degree. C. of more than 8.5 cSt.
6. The Fischer-Tropsch derived medicinal white oil of claim 5,
having a noncyclic isoparaffins content of between 80 and 98 wt %,
a Saybolt color of greater than +30, and Ultra violet adsorption
spectra values as measured by ASTM D 2269 of less than 0.70 in the
280-289 nm spectral band, of less than 0.60 in the 290-299 nm
spectral band, of less than 0.40 in the 300-329 nm spectral band
and of less than 0.09 in the 330-380 nm spectral band as according
to FDA 178 3620 ('c).
Description
[0001] The invention is directed to a process to prepare
Fischer-Tropsch derived medicinal and technical white oils. The
medicinal white oils preferably have a kinematic viscosity at
100.degree. C. of above 8.5 cSt.
[0002] Applicants have developed a new process, which is capable of
preparing various base oil grades, including high viscosity grades,
simultaneously from a relatively heavy Fischer-Tropsch synthesis
product. Such a Fischer-Tropsch synthesis product is for example
obtainable with the process as described in WO-A-9934917.
[0003] The new process comprises hydroprocessing of said feed and
preferably followed by a pour point reducing step. Such a process
is for example described for a different feed in Example 3 of
EP-A-776959. The fraction obtained using the more heavier feedstock
can in turn be separated by means of distillation, at reduced
pressure, into a heavy base oil grade having a kinematic viscosity
at 100.degree. C. of at least 8.5 cSt and one or more base oil
grades having a kinematic viscosity at 100.degree. C. of between 2
and 7 cSt. The heavy base oil grade, which has properties equal or
close to those of a technical white oil, will be obtained in a high
yield as the bottom product of the distillation.
[0004] Colour problems are not readily expected when preparing
products from a Fischer-Tropsch synthesis product because the
Fischer-Tropsch process starts with very pure starting material and
because almost no aromatic colour bearing compounds are normally
formed. It has been found by applicant that this heavy bottom
distillate fraction, at least in our laboratory set-up, could
nevertheless have a slight yellowish colour. Due to this colour the
base oil cannot be directly applied as medicinal white oil.
[0005] Technical and Medicinal white oils are characterized in that
they have no colour. Technical white oils have a Saybolt colour
(ASTM D-156) of greater than +20. Medicinal white oils have a
Saybolt colour of greater than +25, more particularly equal to +30.
Other medicinal and technical white oil specifications are a low UV
adsorbance at different UV spectral ranges according to for Example
FDA 178.3620 (b) and FDA 178.3620 ('c) respectively. Medicinal
white oils for use in food applications further need to have a
kinematic viscosity at 100.degree. C. greater than 8.5 cSt and a 5%
w boiling point greater than 391.degree. C.
[0006] Applicants have now found that by simply contacting a heavy
bottom fraction, which does not meet the required specifications
for either the technical or medicinal white oil with a
heterogeneous adsorbent, a medicinal or technical white oil can be
obtained. The invention is therefore directed to the preparation of
medicinal white oil or a technical white oil from a Fischer-Tropsch
derived paraffinic distillate bottom product, wherein said bottom
product is contacted with a heterogeneous adsorbent.
[0007] Examples of suitable heterogeneous adsorbents are active
carbon, zeolites, for example natural faujasite, or synthetic
materials such as ferrierite, ZSM-5, faujasite, mordenite, metal
oxides such as silica powder, silica gel, aluminium oxyde and
various clays, for example Attapulgus clay (hydrous
magnesium-aluminium silicate), Porocel clay (hydrated aluminium
oxide). A preferred adsorbent is activated carbon.
[0008] In general, activated carbon is a microcrystalline,
nongraphitic form of carbon, which has been processed to develop
internal porosity due to which it has a large surface area.
Activated carbons which have been found particularly suitable, are
those having a surface area (N.sub.2, BET method) in the range from
500 to 1500 m.sup.2/g, preferably from 900 to 1400 m.sup.2/g, and a
Hg pore volume in the range from 0.1 to 1.0 ml/g, preferably from
0.2 to 0.8 ml/g. With the expression "Hg pore volume" is meant the
pore volume as determined by mercury porosimetry. Very good results
have been obtained with activated carbons which additionally have a
micropore size distribution of 0.2 to 2 nm with an average of 0.5
to 1 nm, a pore size distribution (Hg porosimetry) in the range
from 1 to 10,000 nm, preferably from 1 to 5,000 nm, and a total
pore volume as determined by nitrogen porosimetry in the range from
0.4 to 1.5 ml/g, preferably from 0.5 to 1.3 ml/g. Other preferred
physical characteristics include an apparent bulk density of from
0.25 to 0.55 g/ml, a particle size of from 0.4 to 3.5 nm,
preferably 0.5 to 1.5 nm, and a bulk crushing strength of at least
0.8 MPa, preferably at least 1.0 MPa. Examples of suitable
commercially available activated carbons include Chemviron type,
Chemviron F-400 (FILTRASORB 400), DARCO GCL 8*30 and DARCO GCL
12*40 (FILTRASORB and DARCO are trade marks).
[0009] The activated carbon used in the process according to the
present invention is preferably dry activated carbon. This means
that the water content of the activated carbon should be less than
2% by weight, preferably less than 1% by weight and more preferably
less than 0.5% by weight, based on total weight of activated
carbon. This usually means that the activated carbon has to be
dried first before application in the process of the present
invention. Drying can either be performed ex situ or in situ via
conventional drying procedures known in the art. Examples of
suitable drying procedures are those wherein activated carbon is
dried at a temperature in the range of from 100 to 500.degree. C.
for 1 to 48 hours in a nitrogen atmosphere. In case of applying a
fixed bed of activated carbon, in situ drying the activated carbon,
i.e. drying after the activated carbon has been packed into a bed,
is preferred.
[0010] The conditions (temperature, pressure, space velocity) under
which the bottom product is contacted with the activated carbon may
vary within broad ranges in order to still attain an improved base
oil quality. Temperatures in the range of from 20 to 300.degree.
C., preferably 30 to 200.degree. C., more preferably 40 to
150.degree. C., have been found to be suitable in this respect. The
operating pressure of the process according to the present
invention is not particularly critical and may be in the range of
from 1 to 200 bar, preferably 1 to 100 bar, most preferably 1 to 20
bar. A suitable weight hourly space velocity has been found to be
in the range of from 0.2 to 25 kg/l/hr, preferably from 0.5 to 10
kg/l/hr and more preferably from 1 to 5 kg/l/hr. The process
according to the present invention is suitably performed in the
absence of added hydrogen.
[0011] High yields of medicinal white oil can be achieved with the
following process. Process to prepare a medicinal white oil or
technical white oil by:
[0012] (a) hydrocracking/hydroisomerisating a Fischer-Tropsch
derived feed, wherein weight ratio of compounds having at least 60
or more carbon atoms and compounds having at least 30 carbon atoms
in the Fischer-Tropsch derived feed is at least 0.2 and wherein at
least 30 wt % of compounds in the Fischer-Tropsch derived feed have
at least 30 carbon atoms;
[0013] (b) separating the product of step (a) into one or more
distillate fraction(s) of lower boiling fractions and a broad range
base oil precursor fraction;
[0014] (c) performing a pour point reducing step to the broad range
base oil precursor fraction obtained in step (b);
[0015] (d) isolating a heavy bottom distillate fraction by
distilling the product of step (c); and
[0016] (e) contacting said bottom distillate fraction with a
heterogeneous adsorbent.
[0017] The relatively heavy Fischer-Tropsch derived feed as used in
step (a) has at least 30 wt %, preferably at least 50 wt %, and
more preferably at least 55 wt % of compounds having at least 30
carbon atoms. Furthermore the weight ratio of compounds having at
least 60 or more carbon atoms and compounds having at least 30
carbon atoms of the Fischer-Tropsch derived feed is at least 0.2,
preferably at least 0.4 and more preferably at least 0.55. The
Fischer-Tropsch derived feed is preferably derived from a
Fischer-Tropsch product which comprises a C.sub.20+ fraction having
an ASF-alpha value (Anderson-Schulz-Flory chain growth factor) of
at least 0.925, preferably at least 0.935, more preferably at least
0.945, even more preferably at least 0.955.
[0018] The initial boiling point of the Fischer-Tropsch derived
feed may range up to 400.degree. C., but is preferably below
200.degree. C. Preferably at least compounds having 4 or less
carbon atoms and compounds having a boiling point in that range are
separated from a Fischer-Tropsch synthesis product before the
Fischer-Tropsch synthesis product is used as a Fischer-Tropsch
derived feed in step (a). The Fischer-Tropsch derived feed as
described in detail above will for the greater part comprise of a
Fischer-Tropsch synthesis product, which has not been subjected to
a hydroconversion step as defined according to the present
invention. In addition to this Fischer-Tropsch product also other
fractions may be part of the Fischer-Tropsch derived feed. Possible
other fractions may suitably be any high boiling fraction obtained
in step (b).
[0019] Such a Fischer-Tropsch derived feed is suitably obtained by
a Fischer-Tropsch process, which yields a relatively heavy
Fischer-Tropsch product. Not all Fischer-Tropsch processes yield
such a heavy product. An example of a suitable Fischer-Tropsch
process is described in WO-A-9934917 and in AU-A-698392. These
processes may yield a Fischer-Tropsch product as described
above.
[0020] The Fischer-Tropsch derived feed and the resulting waxy
raffinate product will contain no or very little sulphur and
nitrogen containing compounds. This is typical for a product
derived from a Fischer-Tropsch reaction, which uses synthesis gas
containing almost no impurities. Sulphur and nitrogen levels will
generally be below the detection limits, which are currently 5 ppm
for sulphur and 1 ppm for nitrogen.
[0021] The Fischer-Tropsch product may optionally be subjected to a
mild hydrotreatment step in order to remove any oxygenates and
saturate any olefinic compounds present in the reaction product of
the Fischer-Tropsch reaction. Such a hydrotreatment is described in
EP-B-668342. The mildness of the hydrotreatirig step is preferably
expressed in that the degree of conversion in this step is less
than 20 wt % and more preferably less than 10 wt %. The conversion
is here defined as the weight percentage of the feed boiling above
370.degree. C. that reacts to a fraction boiling below 370.degree.
C. After such a mild hydrotreatment lower boiling compounds, having
three or less carbon atoms and other compounds boiling in that
range, will preferably be removed from the effluent before it is
used in step (a).
[0022] The hydrocracking/hydroisomerisation reaction of step (a) is
preferably performed in the presence of hydrogen and a catalyst,
which catalyst can be chosen from those known to one skilled in the
art as being suitable for this reaction. Catalysts for use in step
(a) typically comprise an acidic functionality and a
hydrogenation/dehydrogenation functionality. Preferred acidic
functionalities are refractory metal oxide carriers. Suitable
carrier materials include silica, alumina, silica-alumina,
zirconia, titania and mixtures thereof. Preferred carrier materials
for inclusion in the catalyst for use in the process of this
invention are silica, alumina and silica-alumina. A particularly
preferred catalyst comprises platinum supported on a silica-alumina
carrier. If desired, the acidity of the catalyst carrier may be
enhanced by applying a halogen moiety, in particular fluorine, or a
phosphorous moiety to the carrier. Examples of suitable
hydrocracking/hydro-isomerisa- tion processes and suitable
catalysts are described in WO-A-0014179, EP-A-532118 and the
earlier referred to EP-A-776959.
[0023] Preferred hydrogenation/dehydrogenation functionalities are
Group VIII metals, such a nickel, cobalt, iron, palladium and
platinum. Preferred are the noble metal Group VIII members,
palladium and more preferred platinum. The catalyst may comprise
the more preferred noble metal hydrogenation/dehydrogenation active
component in an amount of from 0.005 to 5 parts by weight,
preferably from 0.02 to 2 parts by weight, per 100 parts by weight
of carrier material. A particularly preferred catalyst for use in
the hydroconversion stage comprises platinum in an amount in the
range of from 0.05 to 2 parts by weight, more preferably from 0.1
to 1 parts by weight, per 100 parts by weight of carrier material.
The catalyst may also comprise a binder to enhance the strength of
the catalyst. The binder can be non-acidic. Examples are clays and
other binders known to one skilled in the art.
[0024] In step (a) the feed is contacted with hydrogen in the
presence of the catalyst at elevated temperature and pressure. The
temperatures typically will be in the range of from 175 to
380.degree. C., preferably higher than 250.degree. C. and more
preferably from 300 to 370.degree. C. The pressure will typically
be in the range of from 10 to 250 bar and preferably between 20 and
80 bar. Hydrogen may be supplied at a gas hourly space velocity of
from 100 to 10000 Nl/l/hr, preferably from 500 to 5000 Nl/l/hr. The
hydrocarbon feed may be provided at a weight hourly space velocity
of from 0.1 to 5 kg/l/hr, preferably higher than 0.5 kg/l/hr and
more preferably lower than 2 kg/l/hr. The ratio of hydrogen to
hydrocarbon feed may range from 100 to 5000 Nl/kg and is preferably
from 250 to 2500 Nl/kg.
[0025] The conversion in step (a) as defined as the weight
percentage of the feed boiling above 370.degree. C. which reacts
per pass to a fraction boiling below 370.degree. C., is at least 20
wt %, preferably at least 25 wt %, but preferably not more than 80
wt %, more preferably not more than 65 wt %. The feed as used above
in the definition is the total hydrocarbon feed fed to step (a),
thus also any optional recycle of the higher boiling fraction as
obtained in step (b).
[0026] In step (b) the product of step (a) is preferably separated
into one or more distillate fractions, a base oil precursor
fraction having preferably a T10 wt % boiling point of between 300
and 450.degree. C. A heavy fraction may be separated from the
product of step (a) to adjust the resultant viscosity of the
medicinal or technical white oil. If no heavy fraction is removed
the kinematic viscosity at 100.degree. C. of the white oil may be
well above 15 cSt. By adjusting the amount and cut point at which
the said heavy fraction is separated from the effluent of step (a)
medicinal or technical white oils can be obtained having a
kinematic viscosity at 100.degree. C. ranging from 6 cSt cSt to
above 25 cSt.
[0027] If a heavy fraction is separated then the T90 wt % boiling
point of the base oil precursor fraction will preferably be between
350 and 550.degree. C. The separation is preferably performed by
means of a first distillation at about atmospheric conditions,
preferably at a pressure of between 1.2-2 bara, wherein the gas oil
product and lower boiling fractions, such as naphtha and kerosine
fractions, are separated from the higher boiling fraction of the
product of step (a). If a high boiling fraction is removed from the
product of step (a) as described above, then this higher boiling
fraction, of which suitably at least 95 wt % boils above
370.degree. C., is further separated in a vacuum distillation step
wherein a vacuum gas oil fraction, the base oil precursor fraction
and the optional higher boiling fraction are obtained. The vacuum
distillation is suitably performed at a pressure of between 0.001
and 0.05 bara.
[0028] In step (c) the base oil precursor fraction obtained in step
(b) is subjected to a pour point reducing treatment. With a 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. The pour point reducing treatment is preferably
performed by means of a so called catalytic dewaxing process.
[0029] The catalytic dewaxing 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 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.
[0030] 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.
[0031] 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-0029511. 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-0029511
and EP-B-832171.
[0032] 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 -10 to -60.degree.
C.
[0033] In step (d) the dewaxed effluent of step (d), optionally
after flashing off some low boiling compounds, is separated into
one or more low viscosity base oil products and a heavy distillate
bottom product. This bottom product is contacted in step (e) with
the heterogeneous adsorbent as described above. This bottom
distillate fraction may for example meet the specifications of a
technical white oil. Thus the present invention is also directed to
a method to up-grade a Fischer-Tropsch derived technical white oil
to a medicinal white oil by contacting the technical white oil with
a heterogeneous adsorbent in the manner described above.
[0034] The invention is further also directed to a medicinal white
oil having a kinematic viscosity at 100.degree. C. of more than 8.5
cSt, a non-cyclic isoparaffins content of between 80 and 98 wt %, a
Saybolt colour of +30, Ultra violet adsorption spectra values as
measured by ASTM D 2269 of less than 0.70 in the 280-289 nm
spectral band, of less than 0.60 in the 290-299 nm spectral band,
of less than 0.40 in the 300-329 nm spectral band and of less than
0.09 in the 330-380 nm spectral band as according to FDA 178.3620
('c).
[0035] The above medicinal white oils may find use as plasticizers
or as a mould release process oil. Such mould release agent may
find advantageous use in food packaging applications.
[0036] The invention will be illustrated by the following
non-limiting examples.
EXAMPLE 1
[0037] A bottom distillate fraction having the properties as listed
in Table 1 (Feed 1) and as obtained by performing the steps (a)-(d)
as described above on a Fischer-Tropsch derived feed was used to
prepare a medicinal white oil. The Fischer-Tropsch derived feed
used in step (a) was the CS-C5750 C.sup.+ fraction of the
Fischer-Tropsch product, as obtained in Example VII using the
catalyst of Example III of WO-A-9934917. The feed contained about
60 wt % C.sub.30+ product. The ratio C.sub.60+/C.sub.30+ was about
0.55.
1 TABLE 1 Feed 1 Feed 2 Kinematic viscosity at 100.degree. C. 7.532
11.11 Density (d20/4) 824.5 831.2 5% w boiling Pt .degree. C. 470
479 Pour point .degree. C. -9 -45 Saybolt Colour -4 (ASTM D 156)
ASTM colour L3.0 (ASTM D 1500)
[0038] The bottom distillate fraction was continuously passed over
a bed of dry coarse particles of "Chenviron" charcoal type F-400 in
upflow mode at 85.degree. C. for about 100 hours, at a rate of 1
g/g.h (about 0.4 l/l.h.).
[0039] The UV adsorption values and Saybolt colour are listed in
Table 2. The results in Table 2 show that a medicinal white oil can
be obtained from a Fischer-Tropsch derived bottom distillate
fraction. The said distillate bottom product in this Example almost
met the technical white oil specifications. The Example thus also
shows that a Fischer-Tropsch derived technical white oil can be
converted to a medicinal white oil by this simple adsorption
process.
EXAMPLE 2
[0040] Example 1 was repeated except that Feed 2 was now used. Feed
2 was obtained in a comparable manner as Feed 1. The catalytic
dewaxing was performed at a higher temperature such that a lower
pour point was obtained for the bottom fraction Feed 2.
2 TABLE 2 Property-> fraction: UV range Saybolt 280-289 nm
290-299 nm 300-329 nm 330-380 nm colour Technical white 4 3.3 2.3
0.8 >+20 oil specification * (maximum values) Medicinal white
0.70 0.60 0.40 0.09 +30 oil specification ** (maximum values) Feed
1 1.11 1.65 2.89 0.9 -4 Feed 2 5.0 4.6 5.0 5.4 Too dark to use
Saybolt Oil as obtained 0.14 0.10 0.03 0.01 +30 in Example 1 Oil as
obtained 0.12 0.10 0.06 0.02 +25 in Example 2 * according to FDA
178.3620 (b) as measured by ASTM 2269 ** according to FDA 178.3620
({grave over ( )}c) as measured by ASTM 2269
* * * * *