lice
2,779,711
Patented den. 29, 1957
2 .
In the practice of the invention, the feed is a raw dis
2,779,711
tillate lubricating oil stock having a viscosity which may
REFINING 0F LUBRICATING OILS
range up to that of the SAE-40 range. Advantageously,
however, the invention is applied to stocks in the viscosity
Louis A. Goretta, Hammond, Ind., assignor to Standard
range of SAE 10 and 20 oils. The feed stock is not treated
’ Gil Company, Chicago, Ill., a corporation of Indiana
by preliminary extraction with acid or solvent and ad
No Drawing. Application February 7&8, 1955,
vantageously is a waxy distillate, i. e. has not been sub
Serial No. 491,199
jected to a preliminary dewaxing operation. The pre
heated stock together with hydrogen is passed in contact
4 Claims,! (Cl. 196-24)
10 with a bed of particle form hydrogenation catalyst, e. g.
a cobalt oxide-molybdenum oxide-alumina catalyst which
This invention relates to improvements in lubricating
has been alkalized by incorporation of an oxide or salt of
oil re?ning and more particularly provides a process for
an alkali metal or alkaline earth metal, e. g. 4 percent
treating raw distillate lubricating oil stocks in the presence
potassium oxide. The catalyst is disposed in the form of a
15 ?xed bed of pellets, pills or beads, and the feed is passed,
of hydrogen and a catalyst.
Conventional lubricating oil re?ning requires one or
advantageously down-?ow, through the catalyst bed. A
more extraction operations with acid or a selective solvent
temperature in the range of about 650° to 850° F., pref
usually followed by clay treating in addition to the stand
erably about 800 to 825° F., and a pressure of about 500
ard distillation and dewaxing or deasphalting operations.
to 2500 p. s. i. g., preferably about 11000 to 1500, are
The availability of cheap by-product hydrogen from cata
maintained. The space velocity may be varied in, the
lystic reforming plants has created a great deal of interest
range of about 0.5 to 10 L. H. S. V., controlling the sever
in the use of hydrogen treating processes, so ‘called hydro
ity of treatment. The hydrogen rate is in the range of
?nishing processes, as an alternative to conventional ex
about 1,000 to 6,000 cubic feet per barrel although hy
drogen consumption is low and ordinarily should not ex
traction and clay treating. Treatment of lubricating oil
stocks under mild conditions of hydrogenation improves 25 ceed about 200 to 400 cubic feet per barrel. After the
feed has been subject to contact with the catalyst under
color, viscosity index, and in general contributes to the
stability of the oil. In practice however, it has been found
the above hydrogenation conditions, unreacted hydrogen
is separated. The unreacted hydrogen may be‘recycled
necessary to operate on partially re?ned stocks, i. e. lubri
or may be diverted to other purposes such as re?nery fuel
cating oil distillates which have been ?rst extracted with
depending upon the design of the facilities. The treated
acid or a solvent and preferably have been treated for
oil is steam or vacuum stripped to remove light ends
removal of wax, in order to avoid costly stock losses
formed in the process.
while attaining the desired improvement in color and
The process of the invention permits the processing of
stability. Thus, in the present state of the art, hydrogena
tion of lubricating oil stocks is in general limited to ?nish
raw waxy stocks directly without preliminary dewaxing
and solvent extraction. Speci?cation products may be ob
ing operations without eliminating expensive acid treat
tained by selective treating at severities low enough to
ing and/ or solvent extraction. When unextracted or raw
stocks are subjected to hydrogenation, the severity of
minimize stock losses, thus protecting the economic gains
made by quality improvement and elimination of conven
treatment required with conventionally available catalysts
tional acid and/or solvent re?ning methods. Processing
results in excessive production of light ends which must
waxy stocks provides a further advantage in improving the
be separated from the treated product to meet ?ash and
viscosity speci?cations.
yield and quality of para?’in waxes produced by sub
sequent dewaxing operations.
A particular problem with raw feeds is color instability
The catalysts used with the process of the invention are
of the treated oils. Although a satisfactory initial color
conveniently any of the conventionally available chromium
is obtained, meeting speci?cations, there is excessive de
oxide-alumina, molybdenum oxide-alumina and cobalt
gradation in color quality upon storage. For example,
oxide-molybdenum oxide-alumina hydrogenation and re
where a conventionally re?ned oil of 1.5 to 2.5 NPA color
forming catalysts, after selective promotion with an
(ASTIvl-D155-45T) may darken upon aging at 100° C.
alkaline substance. A particularly suitable alkali is potas
for 24 hours to 2.0 to 3.0, a hydrogenated oil may darken
sium hydroxide, but other alkali metals such as sodium
to 3.0 to 3.5 or 4.5 or 5.0 NPA. It is undesirable to have
50 and lithium, for example, may be employed, advantage
the color darken more than 1/2 NPA upon aging.
ously in the form of their oxides or hydroxides, but also
I have discovered that a raw distillate lubricating oil
in the form of other Water soluble salts such as borates,
stock can be economically processed to a stable product
under selective conditionstby use of an alkalized hydro
nitrates, carbonates, bicarbonates, acetates, sulfates, phos
genation catalyst. The most suitable catalyst is alkalized
cobalt oxide-molybdenum oxide-alumina, but alkalized
molybdenum oxide-on-alumina'land alkalized chromium
phates and the like. An example of the last named which
55
is particularly suitable is disodium hydrogen phosphate.
Oxides and salts of the alkaline earth metals also have
values, for example calcium oxide or calcium bicarbonate.
The simplest method for incorporation of the ‘alkali pro
known hydrogenation catalysts, however, such as plati
moter is by impregnation with an aqueous solution of the
num-on~alumina and tungsten-nickel sul?de appear to be
distinctly marginal. Surprisingly, the alkalized molyb 60 soluble alkali in the desired concentration. The catalyst
oxide-on~alumina also appear to have value. Other Well
denum and chromium oxide type hydrogenation catalysts
is then dried and calcined at an elevated temperature, e. g.
800 to 1200“ F., for use. Alternatively, the alkali pro
moter may be incorporated in the catalyst composition at
any desired stage in its preparation before drying and
But in processing Waxy or unextracted lubricating oil
stocks, the alkalized catalysts of the invention produce light 65 calcining. The concentration of alkaline promoter may
be in the range of 0.5 to about 10 mol percent, but there
colored oils of satisfactory color speci?cation and stability
is an optimum concentration of alkali promoter for each
where the less selective corresponding unalkalized catalysts
catalyst composition for color stabilization and minimum
do not. Moreover, ‘the production of light ends in the
do not appear to afford any signi?cant advantage in proc
essing extracted or partially re?ned lubricating oil stocks.
hydrogenation process is substantially reduced, by from
stock losses.‘ Sincethe optimum concentration depends
about 25 to upwards of 50 percent, resulting in substantial 70 upon the’ naturegof, thefeed stock and correlation with
process conditionsin addition to. catalyst composition‘; it‘
savings of valuable lubricating oil stock.
is necessary to resort to screening tests to determine the
2379,71 1
best catalyst composition for a given operation. In gen:
eral, a concentration of about 2 to 4 mol percent of alkali
promoter appears to give the best results, particularly with
potassium.
The ‘starting hydrogenation catalysts may be made by
several methods.
and a space velocity of 5 L. H. S. V. in the second series
of runs. an SAE-ZO unextracted distillate Was treated
under the same conditions with a 4 percent K20 on the
chromia-alumina catalyst. The results of the two series
of runs are tabulated below in Tables 1 and 2.
For example, alumina either in the
Table I
form of a synthetic alumina gel or an activated alumina or
bauxite can be impregnated with an aqueous solution of a
NPA Color
salt of the metal giving the desired active oxide upon dry
ing and calcination. Also the catalyst can be prepared by
err-precipitation of the alumina base material with the
Percent K20 in Catalyst
Initial
molybdenum oxide or chromium oxide from a mixture
Aged
2. 8
3.0
2. 3
1.
5
of :aqueous solutions of corresponding salts. The result
ing composites are dried, extruded or pelleted, and cal~
cined. The cobalt oxide-molybdenum oxide-alumina cata
lyst, which represents a preferred form of catalyst for
practicing the invention, may be prepared by impregnating
0. '1
6. U
3. 0
3. 4
4. 0
Table II
a molybdenum oxide-alumina catalyst, or the catalyst may
be prepared by co-precipitation from a mixed aqueous
solution of soluble salts.
NPA Color
The concentration of metal -~
_____I ._____
Initial i Aged
oxides may be varied quite widely in the ?nished catalyst
although in the case of the molybdenum oxide catalysts,
the concentration of molybdenum oxide ordinarily will
Feed ____________________________________________ _ _
2. 3
be less than ‘about 10 mol percent. The proportion of
Product _________________________________________ ._
2. o l
7. 5
3. 7
J) i4.._n#
cobalt also may vary but usually will be in the range of
about 1 mol percent to 6 mol percent. It may be in the
EXAMPLE III
molecular proportions for formation of cobalt molybdate
in the co~precipitated type catalyst if desired. The fol
lowing examples illustrate speci?c aspects of the invention.
A disodium phosphate-cobalt oxide-molybdenum oxide
alurnina catalyst containing 4 mol percent C00, 6 mol per
EXAMPLE I
The catalyst was prepared by dissolving 22 grams of
potassium nitrate in 85 cc. of water and impregnating 200
grams of a commercially available (Oronite) cobalt
cent M003, 5 mol percent NAZHPQ; and 85 mol percent
alumina was prepared by co-preeipitating an aqueous solu
tion of mixed salts of cobalt, molybdenum and aluminum
with disodium phosphate, drying and calcining. An un
extracted SAE-lO para??n distillate having an initial NPA
oxide-molybdenum oxide~alumina catalyst with the re- ‘
color of 2.8 and an aged color of 8 NPA was treated over
the catalyst at 800° E, 1000 p. s. i. g., 5+ 1.. H. S. V.
and 3000 cubic feet of hydrogen per barrel. The treated
11.2 percent M003 and 4 percent K20. The catalyst was
product had an initial NPA color of 1.7 and an aged NPA
dried and calcined at 1000° F. for one hour.
color of 2.7. Approximately 7 percent light ends were
An SAE~10 para?in distillate from a pipe still running
separated when the product was stripped to the initial
40
Mid-Continent crude oil Was used as the feed stock. The
?ash point of the feed before the color determinations.
feed had an initial NPA color of 2.5; after aging for 24
I claim:
hours at 100° C., the NPA color was 4.5. The feed was
1. A process for producing color stable lubricating oil
sulting solution. The catalyst contained 3.6 percent C00,
passed with hydrogen at a rate of 2810 set/barrel over a
bed of 6 to 14 mesh catalyst pellets. The reaction condi
tions were controlled at ‘a temperature of 800° E, a pres
sure of 1000 p. s. i. g. and a space velocity of 5.27
L. H; S; V. The reactor e?°luent was vacuumed stripped to
a pot temperature of 400° F. at 2 to 21/2 mm. The treated
oil had an initial color of 1.6 NPA and an aged color
of 2.4.
The light ends off the treated oil, constituting 2.73 per
cent of the feed, turned dark on standing at room tem
perature for only a few hours. Similar discoloration of
light ends produced by treating with a conventional cobalt
oxide-molybdenum oxide-alumina catalyst or a nickel
tungsten sul?de catalyst has not been observed. Hence,
the color forming bodies responsible for instability appear
to have been preferentially attacked by the alkalized cata
lyst and eliminated with the light ends.
By comparison, treatment with unalkalized, or conven 60
tional, cobalt oxide-"molybdenum oxide-alumina catalyst is
less eifective in color improvement under similar condi
tions and, with respect to color stabilization, is exceed
ingly unreliable. Also the production of light ends is con
siderably higher, being in the range of 9 to 13.5 percent
under the comparable conditions.
EXAMPLE II
_In this example, a series of catalysts were prepared con
taming 0, 2, 4‘and 6 percent K20 on a chromia-‘alumina 70
catalyst containing 18 percent chromia. The catalysts
were prepared by the impregnation method of Example I.
’ In the ?rst series of runs, an SAE-10 waxy distillate was
passed over a bed of the pelleted catalysts at a tempera
ture of 800° F., ‘a pressure of 1000 p. s. i. g. of hydrogen 75
by hydrogenating an unre?ned distillate lubricating oil
stock derived from a mixed-base crude oil which is char
acterized by color instability which process comprises con
tacting the stock with cobalt oxide-molybdenum oxide
alumina hydrogenation catalyst which has been alkalized
by incorporation of ‘about 0.5 to 10 mol percent of an
alkali selected from the group consisting of compounds
of alkali metals ‘and alkaline earth metals, in the presence
of ‘hydrogen at a temperature in the range of about 650°
to 850° F., :a pressure in the range of about 500 to 2500
p. s. i. g. ‘and a space velocity in the range ofv about 0.5 to
10 W. H. S. V.
2. The process of claim 1 in which the catalyst is
alkalized by incorporation of about 2 to 4 mol percent of
potassium oxide.
3. The process of claim 1 in which the catalyst is
stabilized by incorporation of about 2 to 4 mol percent
disodium phosphate.
4. The process of claim 1 in which the unre?ned dis
tillate lubricating oil stock is in the viscosity range of about
SAE—l0 and SAE-ZO oils.
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,441,297
2,442,372
2,608,521
2,697,064
Stirton ______________ __ May 11, 1948
Smith et al. __________ __ June 17, 1947
Hoog _______________ __ Aug. 26, 1952
2,697,683
Engel et al. __________ _- Dec. 31, 1954
Brown ______________ _.._ Dec. 14, 1954
OTHER. REFERENCES
Jones: The Oil and Gas Journal, Nov. 1, 1954.