Technical Field
[0001] The present invention relates to a lubricant base oil.
Background Art
[0002] Conventionally, regarding a lubricant base oil and a lubricant oil composition, satisfaction
of both a high viscosity index and a low-temperature viscosity characteristic has
been attempted.
[0003] For example, by blending an additive agent such as a pour-point depressant into a
lubricant base oil such as a highly-refined mineral oil, improvement of a low-temperature
viscosity characteristic of a lubricant oil has been attempted (for example, refer
to Patent Literature 1 to 3). Moreover, as a producing method of a high viscosity
index base oil, for feedstock containing natural and synthetic normal paraffins, a
method of refining a lubricant base oil by hydrocracking/hydroisomerization is known
(for example, refer to Patent Literature 4 to 6).
[0004] A pour point is generally as an evaluation index of a low-temperature viscosity characteristic
of a lubricant base oil and a lubricant oil. In addition, a technique for evaluating
a low-temperature viscosity characteristic based on a lubricant base oil such as the
content of normal paraffins and isoparaffins is also known.
Citation List
Patent Literature
Summary of Invention
Technical Problem
[0007] As described above, in general, it is considered that colder flow property of a lubricant
base oil is better, and according to the study of the present inventors, a conventional
lubricant base oil having cold flow property has a room for improvement in a lubricating
property.
[0008] The present invention has been made in view of these circumstances, and it is an
object of the present invention to provide a lubricant base oil capable of satisfying
both a low-temperature viscosity characteristic and a lubricating property at a high
level, and a method for producing same.
Solution to Problem
[0009] In order to achieve the above-described object, firstly, the present inventors studied
the reason why a lubricant base oil having a low pour point is inferior in a lubricating
property. As a result, it was found that, in such a lubricant base oil, in addition
to normal paraffins, the content of isoparaffins (for example, main chain is long,
and branched degree is low) whose structure is similar to that of normal paraffins
is also decreased by being highly refined, and thus, a lubricating property tends
to be impaired. According to further study based on such a knowledge, it was found
that, in a lubricant base oil whose kinematic viscosity at 100°C, viscosity index,
freezing point, and SBV viscosity at -20°C satisfy their respective specific conditions,
by making a difference between a freezing point of raffinate obtained by bringing
the lubricant base oil into contact with urea and removing paraffin that can be included
in the urea and the freezing point of the lubricant base oil be within a specific
range, a lubricating property can be improved while maintaining a sufficient low-temperature
viscosity characteristic to complete the present invention.
[0010] Furthermore, in the present invention, as an approach different from improvement
in a low-temperature viscosity characteristic of a lubricant base oil using a pour
point as an index, satisfaction of both a low-temperature viscosity characteristic
and a lubricating property of a lubricant base oil is attempted using an SBV viscosity
as an index. In addition, conventionally, a pour point used as an index of a low-temperature
viscosity characteristic of a lubricant base oil evaluates ease of flow, that is to
say, a bulk viscosity. In contrast, the SBV viscosity in the present invention can
evaluate not a bulk viscosity but mobility of a base oil at the molecular level. For
example, a lubricant base oil does not flow at a temperature lower than a pour point,
but can move at the molecular level due to distortion between molecules constituting
the base oil to impart the SBV viscosity. It was found that, in a lubricant base oil
whose kinematic viscosity at 100°C, viscosity index, and freezing point satisfy their
respective specific conditions by making the SBV viscosity at -20°C of the lubricant
base oil be 3,000 to 60,000 mPa·s and moreover, by making a difference between a freezing
point of raffinate and the freezing point of the lubricant oil be 10°C or more, both
a low-temperature viscosity characteristic and a lubricating property can be satisfied,
and furthermore, a sealing property that is likely to become a problem in a lubricant
base oil having a low pour point can also be improved. The present invention was made
based on the present inventors' own findings as described above.
[0011] That is, the present invention provides a lubricant base oil according to claim 1.
A lubricant base oil [1] is disclosed that is a hydrocarbon oil having a kinematic
viscosity at 100°C of 2.0 to 9 mm
2/s, a viscosity index of 130 or more, a freezing point of -30 to -5°C, and an SBV
viscosity at -20°C of 1,000 to 60,000 mPa·s, in which
the freezing point of the lubricant base oil is higher by 10°C or more than a freezing
point of raffinate obtained by bringing the lubricant base oil into contact with urea
and removing paraffin that can be included in the urea.
[0012] A lubricant base oil [2] according to [1] is disclosed, which is a hydrocarbon oil
having a kinematic viscosity at 100°C of 3.0 to 5.0 mm
2/s, a viscosity index of 145 or more, a freezing point of -20 to -5°C, and an SBV
viscosity at -20°C of 3,000 to 60,000 mPa·s, in which
the freezing point of the lubricant base oil is higher by 10°C or more than a freezing
point of raffinate obtained by bringing the lubricant base oil into contact with urea
and removing paraffin that can be included in the urea.
[0013] A lubricant base oil [3] according to [1] is disclosed, which is a hydrocarbon oil
having a kinematic viscosity at 100°C of 5 to 9 mm
2/s, a viscosity index of 155 or more, a freezing point of -15 to -5°C, and an SBV
viscosity at -20°C of 3,000 to 30,000 mPa·s, in which
the freezing point of the lubricant base oil is higher by 10°C or more than a freezing
point of raffinate obtained by bringing the lubricant base oil into contact with urea
and removing paraffin that can be included in the urea.
[0014] A lubricant base oil [4] according to [1] is disclosed, which is a hydrocarbon oil
having a kinematic viscosity at 100°C of 2.0 to 3.0 mm
2/s, a viscosity index of 130 or more, a freezing point of -30 to - 10°C, and an SBV
viscosity at -30°C of 1,000 to 30,000 mPa·s, in which
the freezing point of the lubricant base oil is higher by 15°C or more than a freezing
point of raffinate obtained by bringing the lubricant base oil into contact with urea
and removing paraffin that can be included in the urea.
[0015] A method [5] for producing a lubricant base oil is disclosed, the method including
a first step of fractionating, from a hydrocarbon oil containing a base oil fraction
and a heavy fraction that is heavier than the base oil fraction, the base oil fraction
and the heavy fraction,
a second step of returning a cracked oil obtained by hydrocracking the heavy fraction
fractionated in the first step, to the first step,
a third step of obtaining a dewaxed oil by performing hydroisomerization dewaxing
of the base oil fraction,
a fourth step of obtaining a refined oil by refining the dewaxed oil, and
a fifth, step of obtaining a lubricant base oil that is a hydrocarbon oil having a
kinematic viscosity at 100°C of 2.0 to 9 mm
2/s, a viscosity index of 130 or more, a freezing point of-30 to -5°C, and an SBV viscosity
at -20°C of 1,000 to 60,000 mPa·s, by fractionation of the refined oil, in which
the third step is a step of performing hydroisomerization dewaxing of the base oil
fraction such that the freezing point of the lubricant base oil obtained in the fifth
step is higher by 10°C or more than a freezing point of raffinate obtained by bringing
the lubricant base oil into contact with urea and removing paraffin that can be included
in the urea.
[0016] A method [6] according to [5] for producing a lubricant base oil is disclosed, in
which
the fifth step is a step of obtaining a lubricant base oil that is a hydrocarbon oil
having a kinematic viscosity at 100°C of 3.0 to 5.0 mm
2/s, a viscosity index of 145 or more, a freezing point of -20 to -5°C, and an SBV
viscosity at -20°C of 3,000 to 60,000 mPa·s, by fractionation of the refined oil,
and
the third step is a step of performing hydroisomerization dewaxing of the base oil
fraction such that the freezing point of the lubricant base oil obtained in the fifth
step is higher by 10°C or more than a freezing point of raffinate obtained by bringing
the lubricant base oil into contact with urea and removing paraffin that can be included
in the urea.
[0017] A method [7] according to [5] for producing a lubricant base oil is disclosed, in
which
the fifth step is a step of obtaining a lubricant base oil that is a hydrocarbon oil
having a kinematic viscosity at 100°C of 5 to 9 mm
2/s, a viscosity index of 155 or more, a freezing point of -15 to -5°C, and an SBV
viscosity at -20°C of 3,000 to 30,000 mPa·s, by fractionation of the refined oil.
[0018] A method [8] according to [5] for producing a lubricant base oil is disclosed, in
which
the fifth step is a step of obtaining a lubricant base oil that is a hydrocarbon oil
having a kinematic viscosity at 100°C of 2.0 to 3.0 mm
2/s, a viscosity index of 130 or more, a freezing point of -20 to -5°C, and an SBV
viscosity at -30°C of 1,000 to 30,000 mPa·s, by fractionation of the refined oil,
and
the third step is a step of performing hydroisomerization dewaxing of the base oil
fraction such that the freezing point of the lubricant base oil obtained in the fifth
step is higher by 10°C or more than a freezing point of raffinate obtained by bringing
the lubricant base oil into contact with urea and removing paraffin that can be included
in the urea.
[0019] A method [9] according to [5]to [8] for producing a lubricant base oil is disclosed,
in which the third step is a step of performing hydroisomerization dewaxing of the
base oil fraction in the presence of a hydroisomerization catalyst containing at least
one crystalline solid acidic substance selected from the group consisting of ZSM-22-type
zeolite, ZSM-23-type zeolite, SSZ32, and ZSM-48-type zeolite, and platinum and/or
palladium as an active metal.
[0020] A method [1] according to [5] - [9] for producing a lubricant base oil is disclosed,
in which the hydrocarbon oil in the first step is obtained by using GTL wax obtained
by a Fischer-Tropsch synthesis or slack wax obtained by solvent dewaxing, as a raw
material.
[0021] Here, the kinematic viscosity and the viscosity index in the present invention mean
a kinematic viscosity and a viscosity index measured in conformity with JIS K 2283-1993,
respectively.
[0022] Moreover, the SBV viscosity in the present invention means a value measured by a
method in which a viscosity is continuously measured by rotating a rotor at 0.3 rpm
while cooling at a cooling rate of 1°C/hour, which is a test method defined in ASTM
D5133.
[0023] In the method for producing a lubricant base oil according to the above-described
[5] to [10], the base oil fraction and the heavy fraction are fractionated from the
hydrocarbon oil as a raw material (first step), and the cracked oil obtained by hydrocracking
the heavy fraction is returned to the first step (second step). That is, since only
the heavy fraction is offered to the subsequent hydroisomerization dewaxing (third
step) after passing through the hydrocracking and the base oil fraction is offered
to hydroisomerization dewaxing without passing through the hydrocracking, isomerization
of the entire treated oil to be offered to hydroisomerization dewaxing becomes difficult
to proceed compared to the conventional method for producing a highly-refined mineral
oil. Then, with respect to such a treated oil, hydroisomerization dewaxing is performed
such that the difference between freezing points of the lubricant base oil to be finally
obtained and raffinate is 10°C or more, and the obtained dewaxed oil is refined to
obtain the refined oil (fourth step), and furthermore, the refined oil is fractionated
(fifth step) so that the desired lubricant base oil can be effectively obtained.
[0024] In addition, as the conventional method for producing a highly-refined mineral oil,
hydrocracking and hydroisomerization dewaxing are generally performed for entire feedstock,
but in this case, it becomes difficult to obtain a lubricant base oil in which all
of a kinematic viscosity at 100°C, a viscosity index, a freezing point, an SBV viscosity
at -20°C, and a difference between freezing points of the lubricant base oil and raffinate
satisfy the above-described conditions, and both a low-temperature viscosity characteristic
and a lubricating property cannot be satisfied.
[0025] In particular, compared to the lubricant base oil according to the above-described
[2] and the method for producing a lubricant base oil according to the above-described
[6], in the case of the conventional method for producing a highly-refined mineral
oil, when the kinematic viscosity at 100°C is within a range of 3.0 to 5.0 mm
2/s, the freezing point tends to be less than -20°C, the SBV viscosity at -20°C tends
to be less than 3,000 mPa·s, and the difference between freezing points of the lubricant
oil and raffinate tends to be less than 10°C.
[0026] Moreover, compared to the lubricant base oil according to the above-described [3]
and the method for producing a lubricant base oil according to the above-described
[7], in the case of the conventional method for producing a highly-refined mineral
oil, when the kinematic viscosity at 100°C is within a range of 5 to 9 mm
2/s, the freezing point tends to be less than -15°C, the SBV viscosity at -20°C tends
to be less than 3,000 mPa·s, and the difference between freezing points of the lubricant
oil and raffinate tends to be less than 10°C.
[0027] Moreover, compared to the lubricant base oil according to the above-described [4]
and the method for producing a lubricant base oil according to the above-described
[8], in the case of the conventional method for producing a highly-refined mineral
oil, when the kinematic viscosity at 100°C is within a range of 2.0 to 3.0 mm
2/s, the freezing point tends to be less than -30°C, the SBV viscosity at -30°C tends
to be less than 1,000 mPa·s, and the difference between freezing points of the lubricant
oil and raffinate tends to be less than 15°C.
Advantageous Effects of Invention
[0028] According to the present invention, a lubricant base oil capable of satisfying both
a low-temperature viscosity characteristic and a lubricating property at a high level,
and a method for producing same are provided. Furthermore, due to the excellent low-temperature
viscosity characteristic and lubricating property, the lubricant base oil of the present
invention has an effect of exhibiting an excellent fuel-consumption saving property
in JC08 cold mode.
Description of Embodiments
[Not according to the invention: Lubricant Base Oil]
[0029] The lubricant base oil is a lubricant base oil that is a hydrocarbon oil having a
kinematic viscosity at 100°C of 2.0 to 9 mm
2/s, a viscosity index of 130 or more, a freezing point of -30 to -5°C, and an SBV
viscosity at - 20°C of 1,000 to 60,000 mPa·s, in which the freezing point of the lubricant
base oil is higher by 10°C or more than a freezing point of raffinate obtained by
bringing the lubricant base oil into contact with urea and removing paraffin that
can be included in the urea.
[0030] Examples of the lubricant base oils according to the invention are lubricant base
oils B and C. An example of a lubricant base oil not according to the invention is
lubricant base oil A.
[Lubricant Base Oil A]
[0031] The lubricant base oil A is a lubricant base oil that is a hydrocarbon oil having
a kinematic viscosity at 100°C of 3.0 to 5.0 mm
2/s, a viscosity index of 145 or more, a freezing point of -20 to -5°C, and an SBV
viscosity at -20°C of 3,000 to 60,000 mPa·s, in which the freezing point of the lubricant
base oil is higher by 10°C or more than a freezing point of raffinate obtained by
bringing the lubricant base oil into contact with urea and removing paraffin that
can be included in the urea.
[0032] The kinematic viscosity of the lubricant base oil A at 100°C is 3.0 to 5.0 mm
2/s , preferably 3.2 to 4.3 mm
2/s, and more preferably 3.4 to 4.1 mm
2/s.
[0033] Moreover, the kinematic viscosity of the lubricant base oil A at 40°C is preferably
10 to 20 mm
2/s, and more preferably 12 to 16 mm
2/s.
[0034] Moreover, the viscosity index of the lubricant base oil A is 145 or more, preferably
147 or more, and more preferably 148 to 160. In addition, if the viscosity index is
less than the above-described lower limit, an energy saving property is decreased,
and if it exceeds the above-described upper limit, fluidity at ordinary temperature
is decreased and the lubricant base oil A tends to be not able to be used as a lubricant
base oil.
[0035] Moreover, the freezing point of the lubricant base oil A is -20 to -5°C, preferably
-18 to -8°C, and more preferably -15 to -10°C. In addition, if the freezing point
is less than the above-described lower limit, an energy saving property is decreased,
and if it exceeds the above-described upper limit, fluidity at ordinary temperature
is decreased and the lubricant base oil A cannot be used as a lubricant base oil.
[0036] Moreover, the SBV viscosity of the lubricant base oil A at - 20°C is 3,000 to 60,000
mPa·s, preferably 3,000 to 30,000 mPa·s, and more preferably 3,000 to 15,000 mPa·s.
If the SBV viscosity at -20°C is less than the above-described lower limit, a sealing
property is insufficient, and if it exceeds the above-described upper limit, a low
temperature temperature characteristic is insufficient.
[0037] Moreover, the SBV viscosity of the lubricant base oil A at - 30°C is preferably 50,000
to 500,000 mPa·s, more preferably 50,000 to 400,000 mPa·s, and further preferably
50,000 to 300,000 mPa·s. If the SBV viscosity at -25°C is less than the above-described
lower limit, a sealing property tends to be insufficient, and if it exceeds the above-described
upper limit, a low temperature temperature characteristic tends to be insufficient.
[0038] Moreover, the freezing point of the lubricant base oil A is higher by 10°C or more,
preferably 10 to 12°C, and more preferably 10 to 14°C than a freezing point of raffinate
obtained by bringing the lubricant base oil into contact with urea and removing paraffin
that can be included in the urea. If the difference between the freezing points is
less than the above-described lower limit, a lubricating property is insufficient,
and if it exceeds the above-described upper limit, fluidity as a base oil is decreased,
and the lubricant base oil tends to be difficult to be used as a base oil.
[0039] Examples of a procedure for obtaining raffinate by bringing the lubricant base oil
into contact with urea and removing paraffin that can be included in the urea include
the following procedure.
[0040] In a round-bottom flask, 100 g of a weighed sample oil (lubricant base oil) is charged,
and 200 g of urea, 360 ml of toluene, and 40 ml of methanol are added to be stirred
at room temperature for 6 hours. Accordingly, a white granular crystal is generated
as a urea adduct in the reaction liquid. The reaction liquid is filtered by a 1 micron
filter to collect the generated white granular crystal, and the obtained crystal is
washed with 50 ml of toluene 6 times. The collected white crystal is charged in a
flask, and 300 ml of pure water and 300 ml of toluene are added to be stirred at 80°C
for 1 hour. A water phase is separation-removed with a separating funnel, and a toluene
phase is washed with 300 ml of pure water 3 times. A dewatering process is performed
by adding a drying agent (sodium sulfate) to the toluene phase, and then, toluene
is distilled away. A rate (mass percentage) of the urea adduct obtained in this manner
to the sample oil is defined as "urea adduct value".
[0041] Furthermore, in the case of performing a
13C-NMR analysis of the lubricant base oil A, a rate of CH
2 carbons constituting the main chain to all carbons constituting the lubricant base
oil is preferably 15% or more, and more preferably 16% or more. If the rate is the
above-described lower limit or more, a traction coefficient of the lubricant base
oil can be decreased (that is, low friction), and it is preferable in terms of an
energy saving property. In addition, the rate of CH
2 carbons constituting the main chain can be determined, for example, by performing
the
13C-NMR analysis under the following analysis conditions.
[0042] The rate of CH
2 to the total amount of the constituent carbons of the lubricant base oil means a
rate of the total of integral intensity attributed to the CH
2 main chain with respect to the total of integral intensity of all carbons, which
are measured by
13C-NMR, and other methods may be used as long as the equivalent result is obtained.
In addition, in the
13C-NMR measurement, a diluted sample obtained by adding 3 g of deuterated chloroform
to 0.5 g of a sample was used, the measurement temperature was room temperature, and
the resonant frequency was 100 MHz. In addition, a gated coupling method was used
as the measurement method.
[0043] Furthermore, in the case of performing an FD-MS analysis of the lubricant base oil
A, a cycloparaflin content is preferably 50% or less, and more preferably 40% or less.
If the cycloparaffin content is the above-described upper limit or less, abrasion
resistance of the lubricant base oil can be further improved. In addition, the rate
of the cycloparaffin content can be determined, for example, by performing the FD-MS
analysis under the following analysis conditions.
[0044] The FD method is an ionization method in which a sample is coated on an emitter,
a current is applied to the emitter to heat the coated sample, and a tunneling effect
is used in a high electrical field on the emitter surface and in the vicinity of the
whisker tip. The measurement was performed using JMS-AX505H by JEOL Ltd. under conditions
of an accelerating voltage (cathode voltage) of 3.0 kV and an emitter current of 2
mA/min. Compound types in mass spectrometry are determined by specific ions to be
formed, and they are generally classified by a z value. The z value is represented
by a general formula C
nH
2n+z for all hydrocarbon species. Since the saturated phase is analyzed separately from
the aromatic phase, contents of different cycloparaffins having the same stoichiometry
can be measured. In addition, cycloparaffins include both of monocyclic cycloparafins
and bicyclic or more cycloparaffins,
[0045] Moreover, from the viewpoint of improving a low-temperature viscosity characteristic
without impairing a viscosity-temperature characteristic at high temperature, the
urea adduct value of the lubricant base oil A is preferably 4% by mass or less, more
preferably 3.5% by mass or less, further preferably 3% by mass or less, and particularly
preferably 2.5% by mass or less. Furthermore, the urea adduct value of the lubricant
base oil may be 0% by mass. However, since a sufficient low-temperature viscosity
characteristic and a lubricant base oil having a higher viscosity index can be obtained,
and furthermore, dewaxing conditions are loosened to result in excellent economic
efficiency, it is preferably 0.1% by mass or more, more preferably 0.5% by mass or
more, and particularly preferably 0.8% by mass or more.
[0046] Moreover, the content of the saturated content in the lubricant base oil A is, on
the basis of the total amount of the lubricant base oil, preferably 90% by mass or
more, more preferably 93% by mass or more, further preferably 95% by mass or more,
and particularly preferably 99% by mass or more. The content of the saturated content
satisfies the above-described condition so that a viscosity-temperature characteristic
and thermal-oxidation stability can be achieved, and furthermore, in the case where
an additive agent is blended into the lubricant base oil, the additive agent is sufficiently
stably dissolved and maintained in the lubricant base oil and functions of the additive
agent can be expressed at a high level. Furthermore, a friction characteristic of
the lubricant base oil itself can be improved, and as a result, improvement in a friction-reducing
effect and therefore improvement in an energy saving property can be achieved. In
addition, the content of the saturated content in the present invention means a value
(unit: % by mass) measured in conformity with ASTM D 2007-93.
[0047] Moreover, the aromatic content in the lubricant base oil A is, on the basis of the
total amount of the lubricant base oil, preferably 5 % by mass or less, more preferably
0.05 to 3% by mass, further preferably 0.1 to 1% by mass, and particularly preferably
0.1 to 0.5% by mass. If the content of the aromatic content exceeds the above-described
upper limit, a viscosity-temperature characteristic, thermal-oxidation stability,
a friction characteristic, and furthermore, a volatilization-preventing property,
and a low-temperature viscosity characteristic tend to be decreased, and moreover,
in the case where an additive agent is blended into the lubricant base oil, an effect
of the additive agent tends to be decreased. Furthermore, although the lubricant base
oil may not contain the aromatic content, solubility of the additive agent can be
further increased by making the content of the aromatic content be 0.05% by mass or
more.
[0048] In addition, the content of the aromatic content means a value measured in conformity
with ASTM D 2007-93. Generally, the aromatic content includes, in addition to alkylbenzenes
and alkylnaphthalenes, anthracene, phenanthrene, alkylated products thereof, and moreover,
compounds in which four benzene rings or more are condensed, and aromatic compounds
having a hetero atom, such as pyridines, quinolines, phenols, and naphthols.
[0049] Furthermore, the content of the sulfur content in the lubricant base oil A depends
on the content of the sulfur content in the raw material. For example, in the case
of using a raw material substantially not containing sulfur, such as a synthetic wax
constituent obtained by a Fischer-Tropsch reaction or the like, a lubricant base oil
substantially not containing sulfur can be obtained. Moreover, in the case of using
a raw material containing sulfur, such as slack wax obtained in the refining process
of the lubricant base oil and micro wax obtained in the wax refining process, the
sulfur content in the obtained lubricant base oil is generally 100 mass ppm or more.
In the lubricant base oil, in terms of further improvement in thermal-oxidation stability
and reduction in the sulfur content, the content of the sulfur content is preferably
10 mass ppm or less, more preferably 5 mass ppm or less, further preferably 3 mass
ppm or less, and particularly preferably 1 mass ppm or less.
[0050] Furthermore, in terms of cost reduction, slack wax or the like is preferably used
as a raw material, and in this case, the sulfur content in the obtained lubricant
base oil is preferably 50 mass ppm or less, and more preferably 10 mass ppm or less.
In addition, the sulfur content means a sulfur content measured in conformity with
JIS K 2541-1996.
[0051] Moreover, the pour point of the lubricant base oil A is preferably -5°C or less,
more preferably -12.5°C or less, and further preferably -12.5°C or less. If the pour
point exceeds the above-described upper limit, cold flow property of the entire lubricant
oil using the lubricant base oil tends to be decreased. Furthermore, the pour point
of the lubricant base oil is preferably -20°C or more, more preferably -17.5°C or
more, and further preferably -15°C or more. If the pour point is less than -20°C,
it becomes difficult for the SBV viscosity at -20°C to be within a range of 3,000
to 60,000 mPa·s, and a scaling property tends to be insufficient. In addition, the
pour point means a pour point measured in conformity with JIS K 2269-1987.
[0052] Moreover, the CCS viscosity of the lubricant base oil A at - 30°C is preferably 1,500
mPa·s or less, and more preferably 1,200 mPa·s or less. Furthermore, the CCS viscosity
of the lubricant base oil at -35°C is preferably 2,500 mPa·s or less, and more preferably
2,000 mPa·s or less. If the CCS viscosity at -30°C or at -35°C exceeds the above-described
upper limit, cold flow property of the entire lubricant oil using the lubricant base
oil tends to be decreased. In addition, the CCS viscosity at -30°C or at -35°C means
a viscosity measured in conformity with JIS K 2010-1993.
[0053] Moreover, the density of the lubricant base oil A at 15°C (ρ
15) is preferably a ρ value represented by the following formula (1) or less, that is
ρ
15≤ρ.
[0054] [In the formula, kv100 represents kinematic viscosity of lubricant base oil at 100°C
(mm
2/s).]
[0055] In addition, in the case of ρ
15>ρ, a viscosity-temperature characteristic, thermal-oxidation stability, and furthermore,
a volatilization-preventing property, and a low-temperature viscosity characteristic
tend to be decreased, and moreover, in the case where an additive agent is blended
into the lubricant base oil, an effect of the additive agent tends to be decreased.
[0056] More specifically, ρ
15 of the lubricant base oil is preferably 0.815 or less, and more preferably 0.810
or less.
[0057] In addition, the density at 15°C in the present invention means a density measured
at 15°C in conformity with JIS K 2249-1995.
[0058] Moreover, the NOACK evaporation of the lubricant base oil A is preferably 8% by mass
or more, more preferably 9% by mass or more, further preferably 10 or more, and moreover,
preferably 15% by mass or less, more preferably 14% by mass or less, and further preferably
13% by mass or less. When the NOACK evaporation is the above-described lower limit,
improvement in a low-temperature viscosity characteristic tends to become difficult.
Furthermore, the NOACK evaporation exceeding the above-described upper limit is not
preferable because, in the case where the lubricant base oil is used for an internal
combustion engine lubricant oil or the like, evaporation loss of the lubricant oil
is increased, and therefore, catalyst poisoning is accelerated. In addition, the NOACK
evaporation means evaporation loss measured in conformity with ASTM D 5800-95.
[Lubricant Base Oil B]
[0059] The lubricant base oil B is a lubricant base oil that is a hydrocarbon oil having
a kinematic viscosity at 100°C of 5 to 9 mm
2/s, a viscosity index of 155 or more, a freezing point of -15 to -5°C, and an SBV
viscosity at -20°C of 3,000 to 30,000 mPa·s, in which the freezing point of the lubricant
oil is higher by 10°C or more than a freezing point of raffinate obtained by bringing
the lubricant base oil into contact with urea and removing paraffin that can be included
in the urea.
[0060] The kinematic viscosity of the lubricant base oil B at 100°C is 5 to 9 mm
2/s, preferably 5.5 to 8.5 mm
2/s, and more preferably 6 to 8 mm
2/s.
[0061] Moreover, the kinematic viscosity of the lubricant base oil B at 40°C is preferably
25 to 40 mm
2/s, and more preferably 28 to 35 mm
2/s.
[0062] Moreover, the viscosity index of the lubricant base oil B is 155 or more, preferably
157 or more, and more preferably 158 to 165. In addition, if the viscosity index is
less than the above-described lower limit, an energy saving property is decreased,
and if it exceeds the above-described upper limit, fluidity at ordinary temperature
is decreased and the lubricant base oil B cannot be used as a lubricant base oil.
[0063] Moreover, the freezing point of the lubricant base oil B is -15 to -5°C, preferably
-14 to -7°C, and more preferably -13 to -8°C. If the freezing point is less than the
above-described lower limit, an energy saving property is decreased, and if it exceeds
the above-described upper limit, fluidity at ordinary temperature is decreased and
the lubricant base oil B cannot be used as a lubricant base oil.
[0064] Moreover, the SBV viscosity of the lubricant base oil B at - 20°C is 3,000 to 30,000
mPa·s, preferably 3,000 to 25,000 mPa·s, and more preferably 3,000 to 20,000 mPa·s.
If the SBV viscosity at -20°C is less than the above-described lower limit, a sealing
property is insufficient, and if it exceeds the above-described upper limit, a low
temperature temperature characteristic is insufficient.
[0065] Moreover, the SBV viscosity of the lubricant base oil B at - 25°C is preferably 5,000
to 500,000 mPa·s, more preferably 5,000 to 400,000 mPa·s, and further preferably 5,000
to 300,000 mPa·s. If the SBV viscosity at -25°C is less than the above-described lower
limit, a sealing property tends to be insufficient, and if it exceeds the above-described
upper limit, a low temperature temperature characteristic tends to be insufficient.
[0066] Moreover, the freezing point of the lubricant base oil B is higher by 10°C or more,
preferably 10 to 20°C, and more preferably 10 to 15°C than a freezing point of raffinate
obtained by bringing the lubricant base oil into contact with urea and removing paraffin
that can be included in the urea. If the difference between the freezing points is
less than the above-described lower limit, a lubricating property is insufficient,
and if it exceeds the above-described upper limit, fluidity as a base oil is decreased,
and the lubricant base oil tends to be difficult to be used as a base oil.
[0067] Furthermore, when performing a
13C-NMR analysis of the lubricant base oil B, a rate of CH
2 carbons constituting the main chain to all carbons constituting the lubricant base
oil is preferably 20% or more, and more preferably 20% or more. If the rate is the
above-described lower limit or more, a traction coefficient of the lubricant base
oil can be decreased (that is, low friction), and it is preferable in terms of an
energy saving property.
[0068] Furthermore, in the case of performing an FD-MS analysis of the lubricant base oil
B, a cycloparaffin content is preferably 60% or less, and more preferably 65% or less.
If the cycloparaffin content is the above-described upper limit or less, abrasion
resistance of the lubricant base oil can be further improved.
[0069] Moreover, from the viewpoint of improving a low-temperature viscosity characteristic
without impairing a viscosity-temperature characteristic at high temperature, the
urea adduct value of the lubricant base oil B is preferably 4% by mass or less, more
preferably 3.5% by mass or less, further preferably 3% by mass or less, and particularly
preferably 2.5% by mass or less. Furthermore, the urea adduct value of the lubricant
base oil may be 0% by mass. However, since a sufficient low-temperature viscosity
characteristic and a lubricant base oil having a higher viscosity index can be obtained,
and furthermore, dewaxing conditions are loosened to result in excellent economic
efficiency, it is preferably 0.1% by mass or more, more preferably 0.5% by mass or
more, and particularly preferably 0.8% by mass or more.
[0070] Moreover, the content of the saturated content in the lubricant base oil B is, on
the basis of the total amount of the lubricant base oil, preferably 90% by mass or
more, more preferably 93% by mass or more, further preferably 95% by mass or more,
and particularly preferably 99% by mass or more. The content of the saturated content
satisfies the above-described condition so that a viscosity-temperature characteristic
and thermal-oxidation stability can be achieved, and furthermore, in the case where
an additive agent is blended into the lubricant base oil, the additive agent is sufficiently
stably dissolved and maintained in the lubricant base oil and functions of the additive
agent can be expressed at a high level. Furthermore, a friction characteristic of
the lubricant base oil itself can be improved, and as a result, improvement in a friction-reducing
effect and therefore improvement in an energy saving property can be achieved.
[0071] Moreover, the aromatic content in the lubricant base oil B is, on the basis of the
total amount of the lubricant base oil, preferably 5% by mass or less, more preferably
0.05 to 3% by mass, further preferably 0.1 to 1% by mass, and particularly preferably
0.1 to 0.5% by mass. If the content of the aromatic content exceeds the above-described
upper limit, a viscosity-temperature characteristic, thermal-oxidation stability,
a friction characteristic, and furthermore, a volatilization-preventing property,
and a low-temperature viscosity characteristic tend to be decreased, and moreover,
in the case where an additive agent is blended into the lubricant base oil, an effect
of the additive agent tends to be decreased. Furthermore, although the lubricant base
oil B may not contain the aromatic content, solubility of the additive agent can be
further increased by making the content of the aromatic content be 0.05% by mass or
more.
[0072] Furthermore, the content of the sulfur content in the lubricant base oil B depends
on the content of the sulfur content in the raw material. For example, in the case
of using a raw material substantially not containing sulfur, such as a synthetic wax
constituent obtained by a Fischer-Tropsch reaction or the like, a lubricant base oil
substantially not containing sulfur can be obtained. Moreover, in the case of using
a raw material containing sulfur, such as slack wax obtained in the refining process
of the lubricant base oil and micro wax obtained in the wax refining process, the
sulfur content in the obtained lubricant base oil is generally 100 mass ppm or more.
In the lubricant base oil of the present invention, in terms of further improvement
in thermal-oxidation stability and reduction in the sulfur content, the content of
the sulfur content is preferably 10 mass ppm or less, more preferably 5 mass ppm or
less, further preferably 3 mass ppm or less, and particularly preferably 1 mass ppm
or less.
[0073] Furthermore, in terms of cost reduction, slack wax or the like is preferably used
as a raw material, and in this case, the sulfur content in the obtained lubricant
base oil is preferably 50 mass ppm or less, and more preferably 10 mass ppm or less.
In addition, the sulfur content in the present invention means a sulfur content measured
in conformity with JIS K 2541-1996.
[0074] Moreover, the pour point of the lubricant base oil B is preferably -5°C or less,
more preferably -10°C or less, and further preferably -12.5°C or less. If the pour
point exceeds the above-described upper limit, cold flow property of the entire lubricant
oil using the lubricant base oil tends to be decreased. Furthermore, the pour point
of the lubricant base oil B is preferably -20°C or more, more preferably -17.5°C or
more, and further preferably -15°C or more. If the pour point is less than -20°C,
it becomes difficult for the SBV viscosity at -20°C to be within a range of 3,000
to 60,000 mPa·s, and a sealing property tends to be insufficient.
[0075] Moreover, the CCS viscosity of the lubricant base oil B at - 30°C is preferably 950
mPa·s or less, and more preferably 900 mPa·s or less. Furthermore, the CCS viscosity
of the lubricant base oil at -35°C is preferably 1,600 mPa·s or less, and more preferably
1,500 mPa·s or less. If the CCS viscosity at -30°C or at -35°C exceeds the above-described
upper limit, cold flow property of the entire lubricant oil using the lubricant base
oil tends to be decreased.
[0076] Moreover, the density of the lubricant base oil B at 15°C (ρ
15) is preferably a p value represented by the following formula (1) or less, that is
ρ
15≤ρ.
[0077] [In the formula, kv100 represents kinematic viscosity of lubricant base oil at 100°C
(mm
2/s).]
[0078] In addition, in the case of ρ
15>ρ, a viscosity-temperature characteristic, thermal-oxidation stability, and furthermore,
a volatilization-preventing property, and a low-temperature viscosity characteristic
tend to be decreased, and moreover, in the case where an additive agent is blended
into the lubricant base oil, an effect of the additive agent tends to be decreased.
[0079] More specifically, ρ
15 of the lubricant base oil is preferably 0.830 or less, and more preferably 0.825
or less.
[0080] In addition, the density at 15°C in the present invention means a density measured
at 15°C in conformity with JIS K 2249-1995.
[Lubricant Base Oil C]
[0081] The lubricant base oil C is a lubricant base oil that is a hydrocarbon oil having
a kinematic viscosity at 100°C of 2.0 to 3.0 mm
2/s, a viscosity index of 130 or more, a freezing point of -30 to - 10°C, and an SBV
viscosity at -30°C of 1,000 to 30,000 mPa·s or less, in which the freezing point of
the lubricant base oil is higher by 15°C or more than a freezing point of raffinate
obtained by bringing the lubricant base oil into contact with urea and removing paraffin
that can be included in the urea.
[0082] The kinematic viscosity of the lubricant base oil C at 100°C is 2.0 to 3.0 mm
2/s, preferably 2.1 to 2.9 mm
2/s, and more preferably 2.2 to 2.8 mm
2/s.
[0083] Moreover, the kinematic viscosity of the lubricant base oil C at 40°C is preferably
7 to 12 mm
2/s, and more preferably 8 to 10 mm
2/s.
[0084] Moreover, the viscosity index of the lubricant base oil C is 130 or more, preferably
131 or more, and more preferably 132 to 140. If the viscosity index is less than the
above-described lower limit, an energy saving property is decreased, and if it exceeds
the above-described upper limit, fluidity at ordinary temperature is decreased and
the lubricant base oil C cannot be used as a lubricant base oil.
[0085] Moreover, the freezing point of the lubricant base oil C is -30 to -10°C, preferably
-29 to -15°C, and more preferably -28 to -20°C. If the freezing point is less than
the above-described lower limit, an energy saving property is decreased, and if it
exceeds the above-described upper limit, fluidity at ordinary temperature is decreased
and the lubricant base oil C cannot be used as a lubricant base oil.
[0086] Moreover, the SBV viscosity of the lubricant base oil C at - 30°C is 1,000 to 30,000
mPa·s, preferably 1,000 to 20,000 mPa·s, and more preferably 1,000 to 15,000 mPa·s.
If the SBV viscosity at -30°C is less than the above-described lower limit, a sealing
property is insufficient, and if it exceeds the above-described upper limit, a low
temperature characteristic is insufficient.
[0087] Moreover, the SBV viscosity of the lubricant base oil C at - 35°C is preferably 3,000
to 500,000 mPa·s, more preferably 3,000 to 400,000 mPa·s, and further preferably 3,000
to 300,000 mPa·s. If the SBV viscosity at -35°C is less than the above-described lower
limit, a sealing property is insufficient, and if it exceeds the above-described upper
limit, a low-temperature viscosity characteristic is insufficient.
[0088] Moreover, the SBV viscosity of the lubricant base oil C at - 40°C is preferably 5,000
to 750,000 mPa·s, more preferably 5,000 to 500,000 mPa·s, and further preferably 5,000
to 400,000 mPa·s. If the SBV viscosity at -40°C is less than the above-described lower
limit, a sealing property is insufficient, and if it exceeds the above-described upper
limit, a low-temperature viscosity characteristic is insufficient.
[0089] Moreover, a value obtained by dividing a freezing point of raffinate, which is obtained
by bringing the lubricant base oil C into contact with urea and removing paraffin
that can be included in the urea, by the freezing point of the lubricant base oil
is 10°C or more, preferably 12 to 20°C, and more preferably 15 to 19°C. If the difference
between the freezing points is less than the above-described lower limit, a lubricating
property is insufficient, and if it exceeds the above-described upper limit, fluidity
as a base oil is decreased, and the lubricant base oil tends to be difficult to be
used as a base oil.
[0090] Furthermore, when performing a
13C-NMR analysis of the lubricant base oil C, a rate of CH
2 carbons constituting the main chain to all carbons constituting the lubricant base
oil is preferably 15% or more, and more preferably 15% or more. If the rate is the
above-described lower limit or more, a traction coefficient of the lubricant base
oil can be decreased (that is, low friction), and it is preferable in terms of an
energy saving property.
[0091] Furthermore, in the case of performing an FD-MS analysis of the lubricant base oil
C, a cycloparaffin content is preferably 30% or less, and more preferably 25% or less.
If the cycloparaffin content is the above-described upper limit or less, abrasion
resistance of the lubricant base oil can be further improved.
[0092] Moreover, from the viewpoint of improving a low-temperature viscosity characteristic
without impairing a viscosity-temperature characteristic at high temperature, the
urea adduct value of the lubricant base oil C is preferably 4% by mass or less, more
preferably 3.5% by mass or less, further preferably 3% by mass or less, and particularly
preferably 2.5% by mass or less. Furthermore, the urea adduct value of the lubricant
base oil may be 0% by mass. However, since a sufficient low-temperature viscosity
characteristic and a lubricant base oil having a higher viscosity index can be obtained,
and furthermore, dewaxing conditions are loosened to result in excellent economic
efficiency, it is preferably 0.1% by mass or more, more preferably 0.5% by mass or
more, and particularly preferably 0.8% by mass or more.
[0093] Moreover, the content of the saturated content in the lubricant base oil C is, on
the basis of the total amount of the lubricant base oil, preferably 90% by mass or
more, more preferably 93% by mass or more, further preferably 95% by mass or more,
and particularly preferably 99% by mass or more. The content of the saturated content
satisfies the above-described condition so that a viscosity-temperature characteristic
and thermal-oxidation stability can be achieved, and furthermore, in the case where
an additive agent is blended into the lubricant base oil, the additive agent is sufficiently
stably dissolved and maintained in the lubricant base oil and functions of the additive
agent can be expressed at a high level. Furthermore, a friction characteristic of
the lubricant base oil itself can be improved, and as a result, improvement in a friction-reducing
effect and therefore improvement in an energy saving property can be achieved.
[0094] Moreover, the aromatic content in the lubricant base oil C is, on the basis of the
total amount of the lubricant base oil, preferably 5% by mass or less, more preferably
0.05 to 3% by mass, further preferably 0.1 to 1% by mass, and particularly preferably
0.1 to 0.5% by mass. If the content of the aromatic content exceeds the above-described
upper limit, a viscosity-temperature characteristic, thermal-oxidation stability,
a friction characteristic, and furthermore, a volatilization-preventing property,
and a low-temperature viscosity characteristic tend to be decreased, and moreover,
in the case where an additive agent is blended into the lubricant base oil, an effect
of the additive agent tends to be decreased. Furthermore, although the lubricant base
oil C may not contain the aromatic content, solubility of the additive agent can be
further increased by making the content of the aromatic content be 0.05% by mass or
more.
[0095] Furthermore, the content of the sulfur content in the lubricant base oil C depends
on the content of the sulfur content in the raw material. For example, in the case
of using a raw material substantially not containing sulfur, such as a synthetic wax
constituent obtained by a Fischer-Tropsch reaction or the like, a lubricant base oil
substantially not containing sulfur can be obtained. Moreover, in the case of using
a raw material containing sulfur, such as slack wax obtained in the refining process
of the lubricant base oil and micro wax obtained in the wax refining process, the
sulfur content in the obtained lubricant base oil is generally 100 mass ppm or more.
In the lubricant base oil of the present invention, in terms of further improvement
in thermal-oxidation stability and reduction in the sulfur content, the content of
the sulfur content is preferably 10 mass ppm or less, more preferably 5 mass ppm or
less, further preferably 3 mass ppm or less, and particularly preferably 1 mass ppm
or less.
[0096] Furthermore, in terms of cost reduction, slack wax or the like is preferably used
as a raw material, and in this case, the sulfur content in the obtained lubricant
base oil is preferably 50 mass ppm or less, and more preferably 10 mass ppm or less.
In addition, the sulfur content in the present invention means a sulfur content measured
in conformity with JIS K 2541-1996.
[0097] Moreover, the pour point of the lubricant base oil C is preferably -5°C or less,
more preferably -12.5°C or less, and further preferably -15°C or less. If the pour
point exceeds the above-described upper limit, cold flow property of the entire lubricant
oil using the lubricant base oil tends to be decreased. Furthermore, the pour point
of the lubricant base oil C is preferably -27.5°C or more, and more preferably -25°C
or more. If the pour point is less than -27.5, it becomes difficult for the SBV viscosity
at -20°C to be within a range of 3,000 to 60,000 mPa·s, and a sealing property tends
to be insufficient.
[0098] Moreover, the CCS viscosity of the lubricant base oil C at - 30°C is preferably 1,000
mPa·s or less, and more preferably 750 mPa·s or less. Furthermore, the CCS viscosity
of the lubricant base oil at - 35°C is preferably 1,300 mPa·s or less, and more preferably
1,000 mPa·s or less. If the CCS viscosity at -30°C or at -35°C exceeds the above-described
upper limit, cold flow property of the entire lubricant oil using the lubricant base
oil tends to be decreased.
[0099] Moreover, the density of the lubricant base oil C at 15°C (ρ
15) is preferably a ρ value represented by the following formula (1) or less, that is
ρ
15≤ρ.
[0100] [In the formula, kv100 represents kinematic viscosity of lubricant base oil at 100°C
(mm
2/s).]
[0101] In addition, in the case of ρ
15>ρ, a viscosity-temperature characteristic, thermal-oxidation stability, and furthermore,
a volatilization-preventing property, and a low-temperature viscosity characteristic
tend to be decreased, and moreover, in the case where an additive agent is blended
into the lubricant base oil, an effect of the additive agent tends to be decreased.
[0102] More specifically, ρ
15 of the lubricant base oil is preferably 0.806 or less, and more preferably 0.8058
or less.
[0103] Moreover, the NOACK evaporation of the lubricant base oil C is preferably 20% by
mass or more, more preferably 25% by mass or more, further preferably 30 or more,
and moreover, preferably 50% by mass or less, more preferably 48% I)y mass or less,
and further preferably 46% by mass or less. When the NOACK evaporation is the above-described
lower limit, improvement in a low-temperature viscosity characteristic tends to become
difficult. Furthermore, the NOACK evaporation exceeding the above-described upper
limit is not preferable because, in the case where the lubricant base oil is used
for an internal combustion engine lubricant oil or the like, evaporation loss of the
lubricant oil is increased, and therefore, catalyst poisoning is accelerated.
[0104] The lubricant base oil according to the present embodiment (including the above-described
lubricant base oils B, and C) excels in a low-temperature viscosity characteristic
and a lubricating property, and can be suitably used as a lubricant base oil for various
applications. Specifically, examples of the applications of the lubricant base oil
according to the present embodiment include lubricant oils used for internal combustion
engines such as passenger vehicle gasoline engines, two-wheel vehicle gasoline engines,
diesel engines, gas engines, gas heat pump engines, marine engines, and power-generating
engines (internal combustion engine lubricant oil), lubricant oils used for driving
transmission devices such as automatic transmissions, manual transmissions, non-stage
transmissions, and final reduction gears (driving transmission device oil), hydraulic
oils used for hydraulic systems such as dampers and construction machines, compressor
oils, turbine oils, industrial gear oils, refrigerant oils, rust preventing oils,
heating medium oils, gas holder seal oils, bearing oils, paper machine oils, machine
tool oils, sliding guide surface oils, electrical insulating oils, cutting oils, press
oils, rolling oils, and heat treating oils, and by using the lubricant base oil according
to the present embodiment for these applications, both a low-temperature viscosity
characteristic and a lubricating property can be satisfied at a high level.
[0105] In the above-described applications, the lubricant base oil according to the present
embodiment may be used alone, or the lubricant base oil according to the present embodiment
may be used in combination with one, or two or more other base oils. In addition,
when the lubricant base oil according to the present embodiment is used in combination
with other base oils, a rate of the lubricant base oil of the present invention in
the mixed-base oil is preferably 30% by mass or more, more preferably 50% by mass
or more, and further preferably 70% by mass or more.
[0106] Other base oils used in combination with the lubricant base oil according to the
present embodiment are not particularly limited, and examples of mineral base oils
include solvent refined mineral oils, hydrocracked mineral oils, hydrorefined mineral
oils, and solvent dewaxed base oils having a kinematic viscosity at 100°C of 1 to
100 mm
2/s, for example.
[0107] Moreover, examples of synthetic base oils include poly-α-olefins or hydrides thereof,
isobutene oligomers or hydrides thereof, isoparaffins, alkylbenzenes, alkylnaphthalenes,
diesters (ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl
adipate, di-2-ethylhexyl sebacate and the like), polyol esters (trimethylolpropane
caprylate, trimethylolpropane pelargonate, pentaerythritol 2-ethylhexanoate, pentaerythritol
pelargonate and the like), polyoxyalkylene glycols, dialkyldiphenyl ethers, and polyphenyl
ethers, and among them, poly-α-olefins are preferable. Typically, examples of the
poly-α-olefins include α-olefin oligomers or co-oligomers having a carbon number of
2 to 32, and preferably 6 to 16 (1-octene oligomer, decene oligomer, ethylene-propylene
co-oligomer and the like) and hydrides thereof.
[0108] Although a producing method of poly-α-olefins is not particularly limited, examples
thereof include a method in which α-olefin is polymerized in the presence of a polymerization
catalyst such as a Friedel-Crafts catalyst including a complex of aluminum trichloride
or boron trifluoride with water, an alcohol (ethanol, propanol, butanol and the like),
a carboxylic acid, or ester.
[0109] Furthermore, various additive agents may be blended into the lubricant base oil according
to the present embodiment or the mixed-base oil of the lubricant base oil and other
lubricant base oils, if necessary. Such additive agents are not particularly limited,
and arbitrary additive agents that are conventionally used in the field of lubricant
oils can be blended. Specifically, examples of the lubricant oil additive agents include
antioxidants, ashless dispersants, detergents, extreme pressure agents, antiwear agents,
viscosity index improvers, pour-point depressants, friction modifiers, oiliness agents,
corrosion inhibitors, rust-preventive agents, demulsifying agents, metal deactivating
agents, seal swelling agents, antifoaming agents, and coloring agents. These additive
agents may be used singly or two or more kinds thereof may be used in combination.
[0110] For example, the lubricant base oil according to the present embodiment can effectively
exhibit the addition effect of a pour-point depressant. Therefore, when the lubricant
base oil according to the present embodiment or the mixed-base oil of the lubricant
base oil and other lubricant base oils contains a pour-point depressant, an excellent
low-temperature viscosity characteristic (MRV viscosity at -40°C is preferably 20,000
mPa·s or less, more preferably 15,000 mPa·s or less, and further preferably 10,000
mPa·s or less) can be achieved. In addition, the MRV viscosity at -40°C described
herein means an MRV viscosity at -40°C measured in conformity with JPI-5S-42-93. For
example, when a pour-point depressant is blended into the above-described base oils
(II) and (V), the MRV viscosity at -40°C can be 12,000 mPa·s or less, and a lubricant
oil composition having an extremely excellent low-temperature viscosity characteristic
of more preferably 10,000 mPa·s or less, further preferably 8,000 mPa·s, and particularly
preferably 6,500 mPa·s or less can be obtained. In this case, the amount of the pour-point
depressant blended is, on the basis of the total amount of the composition, 0.05 to
2% by mass, and preferably 0.1 to 1.5% by mass, in particular, in terms of capable
of decreasing the MRV viscosity, the range of 0.15 to 0.8% by mass is the best, as
the pour-point depressant, one having the weight-average molecular weight of preferably
10,000 to 300,000, and more preferably 50,000 to 200,000 is particularly preferable,
and moreover, as the pour-point depressant, polymethacrylate-based one is particularly
preferable.
[Method for Producing Lubricant Base Oil]
[0111] The method for producing a lubricant base oil includes
a first step of fractionating, from a hydrocarbon oil containing a base oil fraction
and a heavy fraction that is heavier than the base oil fraction, the base oil fraction
and the heavy fraction,
a second step of returning a cracked oil obtained by hydrocracking the heavy fraction
fractionated in the first step, to the first step,
a third step of obtaining a dewaxed oil by performing hydroisomerization dewaxing
of the base oil fraction,
a fourth step of obtaining a refined oil by refining the dewaxed oil, and
a fifth step of obtaining a lubricant base oil that is a hydrocarbon oil having a
kinematic viscosity at 100°C of 2.0 to 9 mm
2/s, a viscosity index of 130 or more, a freezing point of -30 to -5°C, and an SBV
viscosity at -20°C of 1,000 to 60,000 mPa·s, by fractionation of the refined oil,
in which
the third step is a step of performing hydroisomerization dewaxing of the base oil
fraction such that the freezing point of the lubricant base oil obtained in the fifth
step is higher by 10°C or more than a freezing point of raffinate obtained by bringing
the lubricant base oil into contact with urea and removing paraffin that can be included
in the urea.
[0112] The base oil fraction is a fraction for obtaining a lubricant base oil after a dewaxing
step, a hydrofinishing step, and a second distillation step, and the boiling point
range thereof can be appropriately changed based on the intended product. Examples
of the preferred boiling point range of the base oil fraction include 340 to 520°C.
[0113] The heavy fraction is a fraction that has a higher boiling point than the base oil
fraction. It is preferred that a boiling point of the heavy fraction is higher than
520°C.
[0114] The hydrocarbon oil may also contain, other than the base oil fraction and the heavy
fraction, a fraction (light fraction) that has a lower boiling point than the base
oil fraction. It is preferred that a boiling point of the light fraction is lower
than 340°C.
[0115] Examples of the hydrocarbon oil include hydrotreated or hydrocracked gas oil, heavy
gas oil, vacuum gas oil, lubricant oil raffinate, lubricant oil raw material, bright
stock, slack wax (crude wax), foot's oil, deoiled wax, paraffinic wax, microcrystalline
wax, petrolatum, synthetic oils, Fischer-Tropsch synthesis reaction oil (hereinafter
referred to as an "FT synthetic oil"), high-pour-point polyolefins, and straight-chain
α-olefin waxes. These hydrocarbon oils can be used singly or in combinations of two
or more. In particular, the hydrocarbon oil is preferably at least one selected from
the group consisting of a vacuum gas oil, a hydrocracked vacuum gas oil, an atmospheric
residue, a hydrocracked atmospheric residue, a vacuum residue, a hydrocracked vacuum
residue, slack wax, a dewaxed oil, paraffin wax, microcrystalline wax, petrolatum,
and Fischer-Tropsch synthetic wax, and further preferably at least one selected from
the group consisting of an atmospheric residue, a vacuum residue, a vacuum gas oil,
slack wax, and Fischer-Tropsch synthetic wax.
[0116] In one aspect, FT (Fischer-Tropsch) synthetic oil is preferred as the hydrocarbon
oil. The FT synthetic oil is a hydrocarbon oil synthesized from carbon monoxide and
hydrogen by a FT synthesis reaction, and does not contain a nitrogen content. Therefore,
when the hydrocarbon oil is the FT synthetic oil, there is no possibility of sulfur
poisoning in hydrocracking and isomerization dewaxing described below, and a wide
variety of catalysts can be used.
[0117] Further, in another aspect, it is preferred to use as the hydrocarbon oil a petroleum-based
hydrocarbon oil containing petroleum feedstock-derived hydrocarbons. Examples of the
petroleum-based hydrocarbon oil include hydrocracked vacuum gas oil, hydrocracked
atmospheric residue, hydrocracked vacuum residue, slack wax, dewaxed oil, paraffinic
wax, microcrystalline wax, and petrolatum.
[0118] The first step is a step of fractionating the base oil fraction and the heavy fraction
from the hydrocarbon oil. Conditions of the fractionating step can be appropriately
changed based on the composition of the hydrocarbon oil. For example, when the hydrocarbon
oil contains 20% by volume or more of the light fraction, it is preferred that the
fractionating step is carried out by atmospheric distillation for distilling away
the light fraction from the hydrocarbon oil, and vacuum distillation for fractionating
the base oil fraction and the heavy fraction from the bottom oil of the atmospheric
distillation.
[0119] The heavy fraction fractionated in the first step is offered to the second step (hydrocracking
step). The hydrocracked oil obtained in the second step is returned to the first step.
[0120] The form of a reactor used in the hydrocracking step is not particularly limited,
and a fixed-bed flow reactor filled with a hydrocracking catalyst is preferably used.
The reactor may be a single apparatus, or an apparatus in which a plurality of reactors
are arranged in series or in parallel. Moreover, a catalyst bed in the reactor may
be a single bed or a plurality of beds.
[0121] A known hydrocracking catalyst is used as a hydrocracking catalyst and it is preferred
to use a catalyst (hereinafter referred to as a "hydrocracking catalyst A") in which
a metal of groups 8 to 10 of the periodic table of elements having hydrogenation activity
is supported on an inorganic carrier that is a solid acid. Especially, when the hydrocarbon
oil is FT synthetic oil, it is preferred to use the hydrocracking catalyst A, because
there is no risk of catalyst poisoning due to sulfur content.
[0122] Examples of the inorganic carrier that is a preferred solid acid and constitutes
the hydrocracking catalyst A include ones formed from one or more inorganic compounds
selected from zeolites, such as ultrastable Y-type (USY) zeolite, Y-type zeolite,
mordenite, and β-zeolite, as well as amorphous composite metal oxides having heat
resistance such as silica-alumina, silica-zirconia, and alumina-boria. Moreover, the
carrier is more preferably a composition formed from USY zeolite and one or more amorphous
composite metal oxides selected from silica-alumina, alumina-boria, and silica-zirconia,
and further preferably a composition formed from USY zeolite and alumina-boria and/or
silica-alumina.
[0123] USY zeolite is one obtained by ultrastabilizing Y-type zeolite by hydrothermally
treatment and/or acid treatment, in which newly pores having a pore diameter within
a range of 2 to 10 nm are formed in addition to the fine pore structure that Y-type
zeolite inherently has and is called micropores having a pore diameter of 2 nm or
less. The average particle size of the USY zeolite, which although is not especially
limited, is preferably 1.0 µm or less, and more preferably 0.5 µm or less. Further,
the silica/alumina molar ratio (molar ratio of silica based on alumina) in the USY
zeolite is preferably 10 to 200, more preferably 15 to 100, and even more preferably
20 to 60.
[0124] It is preferred that the carrier of the hydrocracking catalyst A includes 0.1 to
80% by mass of crystalline zeolite and 0.1 to 60% by mass of amorphous composite metal
oxide having heat resistance.
[0125] The carrier of the hydrocracking catalyst A can be produced by forming a carrier
composition including the above-described inorganic compound that is a solid acid
and the binder, and then calcining. It is preferred that the blending ratio of the
inorganic compound that is a solid acid is, based on the total mass of the carrier,
1 to 70% by mass, and more preferred is 2 to 60% by mass. Further, if the carrier
includes a USY zeolite, it is preferred that the blending ratio of the USY zeolite
is, based on the total mass of the carrier, 0.1 to 10% by mass, and more preferred
is 0.5 to 5% by mass. Still further, if the carrier includes a USY zeolite and alumina-boria,
it is preferred that the blending ratio of the USY zeolite and the alumina-boria (USY
zeolite/alumina-boria) is 0.03 to 1 by mass. Moreover, if the carrier includes a USY
zeolite and silica-alumina, it is preferred that the blending ratio of the USY zeolite
and the silica-alumina (USY zeolite/silica-alumina) is 0.03 to 1 by mass.
[0126] Although a binder is not particularly limited, alumina, silica, titania, and magnesia
are preferable, and alumina is more preferable. The amount of the binder blended is,
on the basis of the total mass of the carrier, preferably 20 to 98% by mass, and more
preferably 30 to 96% by mass.
[0127] It is preferred that the temperature when calcining the carrier composition is in
the range of 400 to 550°C, more preferred is in the range of 470 to 530°C, and even
more preferred is in the range of 490 to 530°C. By calcining at such a temperature,
sufficient solid acidity and mechanical strength can be imparted to the carrier.
[0128] Specifically, examples of a metal of groups 8 to 10 of the periodic table, which
is supported by a carrier and has hydrogenation activity, include cobalt, nickel,
rhodium, palladium, iridium, and platinum. Among them, it is preferable that metals
selected from nickel, palladium, and platinum be used singly or two or more kinds
thereof be used in combination. These metals may be supported on the above-described
carrier by a conventional method such as impregnation or ion exchange. Although there
is no particular limitation on the amount of supported metal, it is preferred that
the total amount of metal is 0.1 to 3.0% by mass based on the carrier mass. Here,
the term "periodic table of elements" refers to the long form periodic table of elements
as stipulated by the IUPAC (the International Union of Pure and Applied Chemistry).
[0129] In the case of using the hydrocracking catalyst A, conditions when the base oil fraction
is made to be brought into contact with the hydrocracking catalyst A in the presence
of hydrogen are not particularly limited, and the following reaction conditions can
be selected. Specifically, examples of the reaction temperature include 180 to 400°C,
but the reaction temperature is preferably 200 to 370°C, more preferably 250 to 350°C,
and especially preferably 280 to 350°C. If the reaction temperature is more than 400°C,
not only does the yield of the base oil fraction decrease due to the base oil fraction
being broken down into a light fraction, but the generated product is colored, so
that usage as a fuel oil base tends to be limited. On the other hand, if the reaction
temperature is less than 180°C, the hydrocracking reaction does not proceed sufficiently,
so that the yield of the base oil fraction decreases. Examples of the hydrogen partial
pressure include 0.5 to 12 MPa, but the hydrogen partial pressure is preferably 1.0
to 5.0 MPa. If the hydrogen partial pressure is less than 0.5 MPa, the hydrocracking
tends not to proceed sufficiently. On the other hand, if the hydrogen partial pressure
is more than 12 MPa, a high pressure resistance is required for the apparatus, so
that equipment costs tend to increase. Examples of the liquid hourly space velocity
(LHSV) of the heavy fraction include 0.1 to 10.0 h
-1, but the LHSV is preferably 0.3 to 3.5 h
-1. If the LHSV is less than 0.1 h
-1, the hydrocracking tends to proceed excessively, and the productivity tends to decrease.
On the other hand, if the LHSV is more than 10.0 h
-1, the hydrocracking tends not to proceed sufficiently. Examples of the hydrogen/oil
ratio include 50 to 1,000 NL/L, but the hydrogen/oil ratio is preferably 70 to 800
NL/L. If the hydrogen/oil ratio is less than 50 NL/L, the hydrocracking tends not
to proceed sufficiently. On the other hand, if the hydrogen/oil ratio is more than
1,000 NL/L, large-scale hydrogen supply apparatus and the like tend to be required.
[0130] When the hydrocarbon oil is a petroleum-based hydrocarbon oil, sulfur content can
be contained in the base oil fraction. In such a case, it is preferred to use, as
a hydrocracking catalyst, a catalyst (hereinafter referred to as a "hydrocracking
catalyst B") having a porous inorganic oxide that includes two or more elements selected
from aluminum, silicon, zirconium, boron, titanium, and magnesium, and one or more
metals selected from the elements of group 6A and group 8 of the periodic table that
are supported on the porous inorganic oxide. According to the hydrocracking catalyst
B, decrease in the catalytic activity due to sulfur poisoning is sufficiently suppressed.
[0131] As the carrier of the hydrocracking catalyst B, as described above, a porous inorganic
oxide formed from two or more selected from aluminum, silicon, zirconium, boron, titanium,
and magnesium can be used. Such a porous inorganic oxide is, from the perspective
of enabling a much greater improvement in the hydrocracking activity, preferably an
inorganic oxide that includes two or more selected from aluminum, silicon, zirconium,
boron, titanium, and magnesium, and more preferably an inorganic oxide (a composite
oxide of an aluminum oxide and another oxide) that includes aluminum and another element.
[0132] If the porous inorganic oxide contains aluminum as a constituent element, the content
of aluminum is preferably 1 to 97% by mass, more preferably 10 to 97% by mass, and
even more preferably 20 to 95% by mass in terms of alumina, based on the total amount
of the porous inorganic oxide. If the content of aluminum is less than 1% by mass
in terms of alumina, physical properties such as the carrier acid properties are not
preferable, and a sufficient hydrocracking activity tends not to be exhibited. On
the other hand, if the content of aluminum is more than 97% by mass in terms of alumina,
the catalyst surface area is insufficient and the activity tends to decrease.
[0133] The method for introducing silicon, zirconium, boron, titanium, and magnesium, which
are constituent elements of the carrier other than aluminum, into the carrier is not
especially limited. A solution containing these elements or the like may be used as
a raw material. For example, there may be used, for silicon, silicon, liquid glass,
and silica sol; for boron, boric acid; for phosphorus, phosphoric acid and an alkali
metal salt of phosphoric acid; for titanium, titanium sulfide, titanium tetrachloride,
and various alkoxide salts; and for zirconium, zirconium sulfate and various alkoxide
salts.
[0134] Further, the porous inorganic oxide preferably contains phosphorus as a constituent
element. The content of phosphorus is preferably 0.1 to 10% by mass, more preferably
0.5 to 7% by mass, and even more preferably 2 to 6% by mass based on the total amount
of the porous inorganic oxide. If the content of phosphorus is less than 0.1% by mass,
sufficient hydrocracking activity tends not to be exhibited, and if the content of
phosphorus is more than 10% by mass, excessive cracking can proceed.
[0135] It is preferred to add the raw materials for the constituent components of the carrier
other than the above-described aluminum oxide in a step before the calcining of the
carrier. For example, the raw materials are added to an aluminum aqueous solution
in advance and then an aluminum hydroxide gel containing these constituent components
may be prepared or the raw materials may be added to the prepared aluminum hydroxide
gel. Alternatively, the raw materials may be added in a step in which water or an
acidic aqueous solution is added to a commercially available aluminum oxide intermediate
or a boehmite powder, and the resulting mixture is kneaded. However, it is preferred
that the raw materials are allowed to coexist during the stage of preparing the aluminum
hydroxide gel. Although the mechanism for exhibiting the effect of the constituent
components of the carrier other than aluminum oxide is not entirely understood, it
is thought that the constituent components form a complex oxide state with aluminum,
and that this causes an increase in the carrier surface area and interactions with
the active metals to occur, thereby influencing the activity.
[0136] One or more metals selected from the elements of group 6A and group 8 of the periodic
table is supported on the above-described porous inorganic oxide acting as a carrier.
Among these metals, it is preferred to use a combination of two or more metals selected
from cobalt, molybdenum, nickel, and tungsten. Examples of preferred combinations
include cobalt-molybdenum, nickel-molybdenum, nickel-cobalt-molybdenum, and nickel-tungsten.
Among these, more preferred is a combination of nickel-molybdenum, nickel-cobalt-molybdenum,
and nickel-tungsten. During the hydrocracking, these metals are converted into a sulfide
state to use.
[0137] As the content of the active metal based on the catalyst mass, the range of the total
amount of tungsten and molybdenum supported is preferably 12 to 35% by mass, and more
preferably 15 to 30% by mass, in terms of the oxide. If the total amount of tungsten
and molybdenum supported is less than 12% by mass, the active sites decrease and sufficient
activity tends not to be obtained. On the other hand, if the total amount of tungsten
and molybdenum supported is more than 35% by mass, the metals are not effectively
dispersed and sufficient activity tends not to be obtained. The range of the total
amount of cobalt and nickel supported is preferably 1.0 to 15% by mass and more preferably
1.5 to 12% by mass in terms of the oxide. If the total amount of cobalt and nickel
supported is less than 1.0% by mass, a sufficient co-catalyst effect is not obtained
and the activity tends to decrease. On the other hand, if the total amount of cobalt
and nickel supported is more than 15% by mass, the metals are not effectively dispersed
and sufficient activity tends not to be obtained.
[0138] The method for incorporating these active metals into the catalyst is not especially
limited. A known method that is applied when producing a general hydrocracking catalyst
may be employed. Generally, it is preferred to employ a method in which a solution
containing a salt of the active metal is impregnated into the catalyst carrier. In
addition, an equilibrium adsorption method, a pore-filling method, an incipient-wetness
method and the like can also be preferably employed. For example, a pore-filling method
is a method in which the pore volume of a carrier is measured in advance and then
the carrier is impregnated with the same volume of a metal salt solution. In addition,
the impregnation method is not especially limited. The carrier may be impregnated
by a suitable method based on the amount of the metal supported and the physical properties
of the catalyst carrier.
[0139] The number of the hydrocracking catalyst B types to be used is not especially limited.
For example, one type of catalyst may be used singly or a plurality of catalysts with
different active metal species or carrier constituent components may be used. Examples
of a suitable combination when using a plurality of different catalysts include a
catalyst containing cobalt-molybdenum following on from a catalyst containing nickel-molybdenum,
a catalyst containing nickel-cobalt-molybdenum following on from a catalyst containing
nickel-molybdenum, a catalyst containing nickel-cobalt-molybdenum following on from
a catalyst containing nickel-tungsten, and a catalyst containing cobalt-molybdenum
following on from a catalyst containing nickel-cobalt-molybdenum. Prior to and/or
following these combinations, a nickel-molybdenum catalyst may be further combined.
[0140] When combining a plurality of catalysts with different carrier components, a catalyst
may be used that, for example, has an aluminum oxide content in the range of 80 to
99% by mass following on from a catalyst having an aluminum oxide content of 30% by
mass or more and less than 80% by mass based on the total mass of the carrier.
[0141] Further, other than the hydrocracking catalyst B, a guard catalyst, a demetallization
catalyst, and an inactive filler may optionally be used for the purpose of trapping
the scale content which flows in along with the base oil fraction and supporting the
hydrocracking catalyst B at the partition part of the catalyst bed as necessary. These
may be used singly or in combinations thereof.
[0142] It is preferred that the pore volume of the hydrocracking catalyst B as measured
by a nitrogen adsorption BET method is 0.30 to 0.85 ml/g, and more preferred is 0.45
to 0.80 ml/g. If the pore volume is less than 0.30 ml/g, the dispersibility of the
supported metals is insufficient, and the active sites may decrease. In addition,
if the pore volume is more than 0.85 ml/g, the catalyst strength is insufficient,
so that the catalyst may turn into a powder and break up during use.
[0143] Further, it is preferred that the average pore size of the catalyst determined by
a nitrogen adsorption BET method is 5 to 11 nm, and more preferred is 6 to 9 run.
If the average pore size is less than 5 nm, the reaction substrate is not sufficiently
dispersed in the pores, and the reactivity may decrease. In addition, if the average
pore size is more than 11 nm, the pore surface area decreases and the activity may
become insufficient.
[0144] In addition, in the hydrocracking catalyst B, in order to maintain effective catalyst
pores and exhibit sufficient activity, it is preferred that the ratio of the pore
volume derived from pores having a pore diameter of 3 nm or less to the total pore
volume is 35% by volume or less.
[0145] When the hydrocracking catalyst B is used, the hydrocracking conditions can be set
to, for example, a hydrogen pressure of 2 to 13 MPa, a liquid hourly space velocity
(LHSV) of 0.1 to 3.0 h
-1, and a hydrogen-oil ratio (hydrogen/oil ratio) of 150 to 1,500 NL/L, are preferably
a hydrogen pressure of 4.5 to 12 MPa, a liquid hourly space velocity of 0.3 to 1.5
h
-1, and a hydrogen-oil ratio of 380 to 1,200 NL/L, and more preferably a hydrogen pressure
of 6 to 15 MPa, a liquid hourly space velocity of 0.3 to 1.5 h
-1, and a hydrogen-oil ratio of 350 to 1,000 NL/L. All of these conditions are factors
having an influence on the reaction activity. For example, if the hydrogen pressure
and the hydrogen-oil ratio are less than the above lower limits, the reactivity tends
to decrease and the activity tends to rapidly decrease. On the other hand, if the
hydrogen pressure and the hydrogen-oil ratio are more than the above upper limits,
an excessive investment in equipment such as a compressor tends to be required. In
addition, the lower the liquid hourly space velocity is, the more advantageous it
tends to be for the reaction. However, if the liquid hourly space velocity is less
than the above lower limit, a reactor having an extremely large internal volume is
required and an excessive investment in equipment tends to be required. On the other
hand, if the liquid hourly space velocity is more than the above upper limit, the
reaction tends not to sufficiently proceed. Further, the reaction temperature may
be 180 to 400°C, is preferably 200 to 370°C, more preferably 250 to 350°C, and especially
preferably 280 to 350°C. If the reaction temperature is more than 400°C, not only
does the yield of the base oil fraction decrease due to the base oil fraction being
broken down into a light fraction, but the generated product is colored, so that usage
as a fuel oil base tends to be limited. On the other hand, if the reaction temperature
is less than 180°C, the hydrocracking reaction does not proceed sufficiently, so that
the yield of the base oil fraction decreases.
[0146] In the hydrocracking step, the heavy fraction is, due to the hydrocracking, converted
into hydrocarbons having a boiling point of about 520°C or less. On the other hand,
a part of the heavy fraction is not sufficiently hydrocracked, and remains as an uncracked
heavy fraction having a boiling point of 520°C or more.
[0147] The composition of the hydrocracked oil is determined based on the hydrocracking
catalyst to be used and the hydrocracking reaction conditions. Here, unless otherwise
stated, the "hydrocracked oil" refers to all the products of hydrocracking, including
the uncracked heavy fraction. If the hydrocracking reaction conditions are severer
than necessary, although the content of the uncracked heavy fraction in the hydrocracked
oil decreases, a light fraction having a boiling point of 340°C or less increases,
and the yield of the preferred base oil fraction (340 to 520°C fraction) decreases.
On the other hand, if the hydrocracking reaction conditions are milder than necessary,
the content of the uncracked heavy fraction increases, and the base oil fraction yield
decreases. In the case where the ratio M2/M1 of the mass M2 of the cracking products
having a boiling point of 25 to 520°C to the mass M1 of all the cracking products
having a boiling point of 25°C or more is referred to as a "cracking ratio", generally,
the reaction conditions are preferably selected such that the cracking ratio M2/M1
is 5 to 70%, preferably 10 to 60%, and further preferably 20 to 50%.
[0148] Next, the third step (dewaxing step) will be described. In the dewaxing step, the
base oil fraction fractionated in the first step is brought into contact with a hydrocracking
catalyst in the presence of hydrogen (molecular hydrogen). Accordingly, the base oil
fraction is dewaxed by hydroisomerization to obtain a dewaxed oil. At this time, hydroisomerization
dewaxing of the above-described base oil fraction is performed such that a freezing
point of the lubricant base oil obtained in the fifth step described below is higher
by 10°C or more (15°C or more in the case of producing the lubricant base oil C) than
a freezing point of raffinate obtained by bringing the lubricant base oil into contact
with urea and removing paraffin that can be included in the urea.
[0149] As a tube reactor for the dewaxing step, a known fixed-bed tube reactor can be used.
More specifically, for example, hydroisomerization can be performed by filling a fixed-bed
flow reactor with a hydroisomerization catalyst and making hydrogen (molecular hydrogen)
and the base oil fraction flow through the reactor.
[0150] As the hydroisomerization catalyst, a catalyst that is generally used for hydroisomerization,
namely, a catalyst in which a metal having a hydrogenation activity is supported on
an inorganic carrier, can be used.
[0151] As the metal having a hydrogenation activity and constituting the hydroisomerization
catalyst, one or more metals selected from the group consisting of metals of group
6, group 8, group 9, and group 10 of the periodic table of elements are used. Specific
examples of these metals include noble metals such as platinum, palladium, rhodium,
ruthenium, iridium, and osmium, or cobalt, nickel, molybdenum, tungsten, and iron.
Preferred are platinum, palladium, nickel, cobalt, molybdenum, and tungsten, and more
preferred are platinum and palladium. In addition, it is also preferred to use these
metals in combinations of a plurality of species. In this case, examples of preferred
combinations include platinum-palladium, cobalt-molybdenum, nickel-molybdenum, nickel-cobalt-molybdenum,
and nickel-tungsten.
[0152] Examples of inorganic carriers constituting the hydroisomerization catalyst include
metal oxides such as alumina, silica, titania, zirconia, and boria. These metal oxides
may be one kind, a mixture of two or more kinds, or a composite metal oxide such as
silica-alumina, silica-zirconia, alumina-zirconia, and alumina-boria. From the perspective
of efficiently promoting the hydroisomerization of normal paraffins, the inorganic
carrier is preferably a composite metal oxide that is a solid acid, such as silica-alumina,
silica-zirconia, alumina-zirconia, and alumina-boria. Further, a small amount of zeolite
may be included in the inorganic carrier. In order to improve the moldability and
mechanical strength of the carrier, the inorganic carrier may be blended with a binder.
Examples of preferred binders include alumina, silica, and magnesia.
[0153] As the content of the metal having a hydrogenation activity in the hydroisomerization
catalyst, if this metal is the above-described noble metal, it is preferred that the
content is about 0.1 to 3% by mass based on the mass of the carrier as metal atoms.
Further, if this metal is a metal other than the above-described noble metals, it
is preferred that the content is about 2 to 50% by mass based on the mass of the carrier
as a metal oxide. If the content of the metal having a hydrogenation activity is less
than the above-described lower limit, hydrorefining and hydroisomerization tend not
to proceed sufficiently. On the other hand, if the content of the metal having a hydrogenation
activity is more than the above-described upper limit, dispersion of the metal having
a hydrogenation activity deteriorates, so that the activity of the catalyst tends
to decrease, and the catalyst cost increases.
[0154] Further, the hydroisomerization catalyst may be a catalyst in which one or more metals
selected from the elements of group 8 of the periodic table that is supported on a
carrier including a porous inorganic oxide that is formed from a substance selected
from aluminum, silicon, zirconium, boron, titanium, magnesium, and zeolite.
[0155] Examples of the porous inorganic oxide used as a carrier of such a hydroisomerization
catalyst include alumina, titania, zirconia, boria, silica, or zeolite, and of these,
preferred is a porous inorganic oxide formed from alumina and at least one of titania,
zirconia, boria, silica, and zeolite. The production method is not especially limited,
but an arbitrary preparation method may be employed that uses raw materials in the
form of various sols or salt compounds corresponding to the respective elements. Furthermore,
the carrier may be prepared by once preparing a composite hydroxide or a composite
oxide, such as silica-alumina, silica-zirconia, alumina-titania, silica-titania, and
alumina-boria, and then adding the composite hydroxide or composite oxide in the form
of an alumina gel or other hydroxide, or in the form an appropriate solution, at an
arbitrary stage of the preparation step. The proportion of alumina to the other oxide
may be any ratio based on the carrier, but the content of alumina is preferably 90%
by mass or less, more preferably 60% by mass or less, even more preferably 40% by
mass or less, and preferably 10% by mass or more, and more preferably 20% by mass
or more.
[0156] Examples of the zeolite, which is a crystalline alumino silicate, include faujasite,
pentasil, mordenite, TON, MTT, and MRE. A zeolite that has been ultrastabilized by
a predetermined hydrothermal treatment and/or acid treatment, or a zeolite whose alumina
content has been adjusted may be used. It is preferred to use faujasite or mordenite,
and especially preferred to use a Y or beta type. The Y type is preferably ultrastabilized.
A zeolite ultrastabilized by a hydrothermal treatment has, in addition to its inherent
pore structure, called micropores, of 20 angstroms or less, newly formed pores in
the range of 20 to 100 angstroms. The hydrothermal treatment may be carried out under
known conditions.
[0157] As the active metal of such a hydroisomerization catalyst, one or more metals selected
from the elements of group 8 of the periodic table can be used. Among these metals,
preferably used are one or more metals selected from Pd, Pt, Rh, Ir, Au and Ni, and
more preferably used is a combination thereof. Examples of a preferred combination
include Pd-Pt, Pd-Ir, Pd-Rh, Pd-Au, Pd-Ni, Pt-Rh, Pt-Ir, Pt-Au, Pt-Ni, Rh-Ir, Rh-Au,
Rh-Ni, Ir-Au, Ir-Ni, Au-Ni, Pd-Pt-Rh, Pd-Pt-Ir, and Pt-Pd-Ni. Among these, more preferred
combinations are Pd-Pt, Pd-Ni, Pt-Ni, Pd-Ir, Pt-Rh, Pt-Ir, Rh-Ir, Pd-Pt-Rh, Pd-Pt-Ni,
and Pd-Pt-Ir, and even more preferred combinations are Pd-Pt, Pd-Ni, Pt-Ni, Pd-Ir,
Pt-Ir, Pd-Pt-Ni, and Pd-Pt-Ir.
[0158] The total content of the active metals is preferably 0.1 to 2% by mass, more preferably
0.2 to 1.5% by mass, and even more preferably 0.5 to 1.3% by mass, in terms of metal,
based on catalyst mass. If the total amount of metals supported is less than 0.1%
by mass, the number of active sites is reduced, so that sufficient activity tends
not to be obtained. On the other hand, if the total amount of metals supported is
more than 2% by mass, the metals are not dispersed effectively, so that sufficient
activity tends not to be obtained.
[0159] For any of the above-described hydroisomerization catalysts, the method for supporting
the active metal on the carrier is not especially limited. A known method that is
applied when producing a general hydroisomerization catalyst may be employed. Generally,
it is preferred to employ a method in which a solution containing a salt of the active
metal is impregnated into the catalyst carrier. In addition, an equilibrium adsorption
method, a pore-filling method, an incipient-wetness method and the like can also be
preferably employed. For example, a pore-filling method is a method in which the pore
volume of a carrier is measured in advance and then the carrier is impregnated with
the same volume of a metal salt solution. Although the impregnation method is not
especially limited, the carrier may be impregnated by a suitable method based on the
amount of the metal supported and the physical properties of the catalyst carrier.
[0160] As the hydroisomerization catalyst, the following catalyst can also be used.
<Specific Aspect of the Hydroisomerization Catalyst>
[0161] The hydroisomerization catalyst according to this aspect is imparted with its characteristics
as a result of being produced by a specific method. The hydroisomerization catalyst
according to the present aspect will now be described with reference to a preferred
production aspect thereof.
[0162] The method for producing the hydroisomerization catalyst according to the present
aspect includes a first step of obtaining a carrier precursor by heating a mixture
that includes an ion-exchanged zeolite obtained by ion-exchanging an organic template-containing
zeolite that contains an organic template and has a one-dimensional, 10-membered ring
pore structure in a solution containing ammonium ions and/or protons, and a binder,
in a N
2 atmosphere at a temperature of 250 to 300°C, and a second step of obtaining a hydroisomerization
catalyst in which platinum and/or palladium is supported on a carrier including zeolite
by calcining a catalyst precursor incorporating a platinum salt and/or palladium salt
in the carrier precursor in an atmosphere containing molecular oxygen at a temperature
of 350 to 400°C.
[0163] From the perspective of achieving a high level of both high isomerization activity
and suppressed cracking activity in the hydroisomerization reactions of normal paraffins,
the organic template-containing zeolite used in the present aspect has a one-dimensional
pore structure formed from a 10-membered ring. Examples of such zeolites include AEL,
EUO, FER, HEU, MEL, MFI, NES, TON, MTT, WEI, *MRE, and SSZ-32. The above three-lettered
acronyms represent framework-type codes assigned to various structures of classified
molecular sieve-type zeolites by the Structure Commission of the International Zeolite
Association. It is also noted that zeolites having the same topology are collectively
designated by the same code.
[0164] Among the above-described zeolites having a one-dimensional, 10-membered ring pore
structure, from the perspective of high isomerization activity and low cracking activity,
preferred as the organic template-containing zeolite are zeolites having a TON or
an MTT structure, zeolite ZSM-48, which is a zeolite having a *MRE structure, and
zeolite SSZ-32. Zeolite ZSM-22 is more preferred among zeolites having the TON structure,
and zeolite ZSM-23 is more preferred among zeolites having the MTT structure.
[0165] The organic template-containing zeolite is hydrothermally synthesized according to
a known method from a silica source, an alumina source, and an organic template that
is added to build the above-described predetermined pore structure.
[0166] The organic template is an organic compound having an amino group, an ammonium group
and the like, and is selected according to the structure of the zeolite to be synthesized.
However, it is preferred that the organic template is an amine derivative. Specifically,
the organic template is preferably at least one selected from the group consisting
of alkylamines, alkyldiamines, alkyltriamines, alkyltetramines, pyrrolidine, piperazine,
aminopiperazine, alkylpentamines, alkylhexamines, and their derivatives.
[0167] The molar ratio of the silicon element to aluminum element ([Si]/[Al]; hereinafter
referred to as a "Si/Al ratio") that constitute the organic template-containing zeolite
having a one-dimensional, 10-membered ring pore structure is preferably 10 to 400,
and more preferably 20 to 350. If the Si/Al ratio is less than 10, although the activity
for the conversion of normal paraffins increases, the isomerization selectivity to
isoparaffins decreases, and cracking reactions caused by an increase in the reaction
temperature tend to sharply increase, which is undesirable. Conversely, if the Si/Al
ratio is more than 400, the catalytic activity needed for the conversion of normal
paraffins cannot be easily obtained, which is undesirable.
[0168] The synthesized organic template-containing zeolite, which has preferably been washed
and dried, typically has alkali metal cations as counter cations, and incorporates
the organic template in its pore structure. The zeolite containing an organic template,
which is used for producing the hydroisomerization catalyst according to the present
invention, is preferably in such a synthesized state, i.e., preferably, the zeolite
has not been subjected to a calcining treatment for removing the organic template
incorporated therein.
[0169] The organic template-containing zeolite is next ion-exchanged in a solution containing
ammonium ions and/or protons. By the ion-exchange treatment, the counter cations contained
in the organic template-containing zeolite are exchanged for ammonium ions and/or
protons. Further, at the same time, a portion of the organic template incorporated
in the organic template-containing zeolite is removed.
[0170] The solution used for the ion-exchange treatment is preferably a solution that uses
a solvent containing at least 50% by volume of water, and more preferably is an aqueous
solution. Examples of compounds for supplying ammonium ions into the solution include
various inorganic and organic ammonium salts, such as ammonium chloride, ammonium
sulfate, ammonium nitrate, ammonium phosphate, and ammonium acetate. On the other
hand, mineral acids such as hydrochloric acid, sulfuric acid, and nitric acid are
typically used as compounds for supplying protons into the solution. The ion-exchanged
zeolite (here, an ammonium-form zeolite) obtained by ion exchange of the organic template-containing
zeolite in the presence of ammonium ions releases ammonia during subsequent calcination,
and the counter cations are converted into protons to form Bronsted acid sites. Ammonium
ions are preferred as the cationic species used for the ion exchange. The amount of
ammonium ions and/or protons contained in the solution is preferably set to 10 to
1,000 equivalents based on the total amount of the counter cations and organic template
contained in the organic template-containing zeolite used.
[0171] The ion-exchange treatment may be performed on the organic template-containing zeolite
simple substance in powder form, or alternatively, prior to the ion-exchange treatment,
the organic template-containing zeolite may be blended with an inorganic oxide, which
is a binder, and molded, and the ion-exchange treatment may be performed on the resulting
molded body. However, if the molded body is subjected to the ion-exchange treatment
in an uncalcined state, problems such as the molded body collapsing and turning into
a powder tend to occur. Therefore, it is preferred to subject the organic template-containing
zeolite in powder form to an ion-exchange treatment.
[0172] The ion-exchange treatment is preferably performed based on a standard method, i.e.,
a method in which the zeolite containing an organic template is dipped in a solution,
preferably an aqueous solution, containing ammonium ions and/or protons, and the solution
is stirred or fluidized. It is preferred to perform the stirring or fluidization under
heating to increase the ion-exchange efficiency. In the present aspect, especially
preferred is a method in which the aqueous solution is heated, boiled, and ion-exchanged
under reflux.
[0173] Further, from the perspective of increasing the ion-exchange efficiency, during the
ion exchange of the zeolite in a solution, it is preferred to exchange the solution
with a fresh one once or twice or more, and more preferably exchanged with a fresh
one once or twice. When exchanging the solution once, the ion-exchange efficiency
can be improved by, for example, dipping the organic template-containing zeolite in
a solution containing ammonium ions and/or protons, and heating the solution under
reflux for 1 to 6 hours, followed by exchanging the solution with a fresh one, and
further heating under reflux for 6 to 12 hours.
[0174] By the ion-exchange treatment, substantially all of the counter cations such as an
alkali metal in the zeolite can be exchanged for ammonium ions and/or protons. On
the other hand, regarding the organic template incorporated in the zeolite, although
a portion of the organic template is removed by the ion-exchange treatment, it is
generally difficult to remove all of the organic template even if the ion-exchange
treatment is repeatedly performed, so that a portion of the organic template remains
inside the zeolite.
[0175] In the present aspect, a carrier precursor is obtained by heating a mixture in which
the ion-exchanged zeolite and the binder are included in a nitrogen atmosphere at
a temperature of 250 to 350°C.
[0176] The mixture in which the ion-exchanged zeolite and the binder are included is preferably
obtained by blending an inorganic oxide, which is a binder, with the ion-exchanged
zeolite obtained by the above-described method, and molding the resulting composition
to form a molded body. The purpose of blending an inorganic oxide with the ion-exchanged
zeolite is to increase the mechanical strength of the carrier (in particular, a particulate
carrier) obtained by calcining the molded body to a degree that can withstand practical
applications. However, the present inventor found that the selection of the type of
inorganic oxide affects the isomerization selectivity of the hydroisomerization catalyst.
From this perspective, at least one inorganic oxide selected from alumina, silica,
titania, boria, zirconia, magnesia, ceria, zinc oxide, phosphorus oxide, and a composite
oxide containing a combination of two or more of these oxides can be used as the inorganic
oxide. Among the above, silica and alumina are preferred, and alumina is more preferred,
from the perspective of further improving the isomerization selectivity of the hydroisomerization
catalyst. The phrase "composite oxide containing a combination of two or more of these
oxides" refers to a composite oxide containing at least two components from alumina,
silica, titania, boria, zirconia, magnesia, ceria, zinc oxide, and phosphorus oxide,
but is preferably an alumina-based composite oxide containing 50% by mass or more
of an alumina component based on the composite oxide, and among those, is more preferably
alumina-silica.
[0177] The blending ratio of the ion-exchanged zeolite and the inorganic oxide in the above-described
composition is preferably 10:90 to 90:10, and more preferably 30:70 to 85:15, in terms
of the mass ratio of the ion-exchanged zeolite to the inorganic oxide. If this ratio
is less than 10:90, the activity of the hydroisomerization catalyst tends to be insufficient,
which is undesirable. Conversely, if the ratio is more than 90:10, the mechanical
strength of the carrier obtained by molding and calcining the composition tends to
be insufficient, which is undesirable.
[0178] Although the method for blending the inorganic oxide with the ion-exchanged zeolite
is not especially limited, a general method can be employed, such as, for example,
a method in which a suitable amount of a liquid such as water is added to the powders
of both components to form a viscous fluid, and the fluid is kneaded in a kneader
or the like.
[0179] The composition containing the ion-exchanged zeolite and inorganic oxide, or a viscous
fluid including the composition, is molded by a method such as extrusion molding,
and is preferably dried, to form a particulate molded body. Although the shape of
the molded body is not especially limited, examples of the shape include a cylindrical
shape, a pellet shape, a spherical shape, and an irregular tubular shape having a
three leaf shaped or a four leaf shaped cross-section. Although the size of the molded
body is not especially limited, the molded body is preferably, for example, about
1 to 30 mm in the long axis, and about 1 to 20 mm in the short axis, from the perspective
of the ease of handling, the load density in the reactor and the like.
[0180] In the present aspect, it is preferred to form the carrier precursor by heating the
thus-obtained molded body in a N
2 atmosphere at a temperature of 250 to 350°C. Regarding the heating time, preferred
is 0.5 to 10 hours, and more preferred is 1 to 5 hours.
[0181] In the present aspect, if the above-described heating temperature is less than 250°C,
a large amount of organic template remains, and the zeolite pores become blocked with
the remaining template. The isomerization active sites are thought to exist near the
pore mouth. Thus, in the above case, the reaction substrate cannot disperse into the
pores due to the pore blockage, so that the active sites become covered, the isomerization
reaction does not easily proceed, and a normal paraffin conversion rate tends not
to be sufficiently obtained. On the other hand, if the heating temperature is more
than 350°C, the isomerization selectivity of the obtained isomerization catalyst does
not sufficiently improve.
[0182] It is preferred that the lower limit for the temperature when forming the carrier
precursor by heating the molded body is 280°C or more, and that the upper limit for
the temperature is 330°C or less.
[0183] In the present aspect, it is preferred to heat the above-described mixture so that
a portion of the organic template included in the molded body remains. Specifically,
it is preferred to set the heating conditions so that the micropore volume per unit
mass of the hydroisomerization catalyst obtained by calcining after the below-described
metal supporting is 0.02 to 0.11 cc/g, and the micropore volume per unit mass of the
zeolite that is contained in that catalyst is 0.04 to 0.12 cc/g.
[0184] Next, the catalyst precursor incorporating a platinum salt and/or palladium salt
in the above-described carrier precursor is calcined in an atmosphere containing molecular
oxygen at a temperature of 350 to 400°C, preferably 380 to 400°C, and more preferably
400°C, to obtain a hydroisomerization catalyst in which a platinum and/or palladium
is supported on a carrier including zeolite. Here, "in an atmosphere containing molecular
oxygen" means bringing into contact with a gas including oxygen gas, and of those
preferably air. The calcining time is preferably 0.5 to 10 hours, and more preferably
1 to 5 hours.
[0185] Examples of the platinum salt include chloroplatinic acid, tetraammineplatinum dinitrate,
dinitroaminoplatinum, and tetraamminedichloroplatinum. Since chloride salts can produce
hydrochloric acid during a reaction, which may cause apparatus corrosion, tetraammineplatinum
dinitrate, which is a platinum salt that is not a chloride salt and in which a high
level of platinum is dispersed, is preferred.
[0186] Examples of the palladium salt include palladium chloride, tetraammine palladium
nitrate, and diaminopalladium nitrate. Since chloride salts can produce hydrochloric
acid during a reaction, which may cause apparatus corrosion, tetraammine palladium
nitrate, which is a palladium salt that is not a chloride salt and in which a high
level of palladium is dispersed, is preferred.
[0187] The amount of the active metal supported on the carrier including zeolite according
to the present aspect is preferably 0.001 to 20% by mass, and more preferably 0.01
to 5% by mass, based on the mass of the carrier. If the amount supported is less than
0.001% by mass, it is difficult to impart a predetermined hydrogenation/dehydrogenation
function to the catalyst. Conversely, if the amount supported is more than 20% by
mass, conversion on the active metal of hydrocarbons into lighter products by cracking
tends to proceed, so that the yield of the intended fraction tends to decrease, and
the catalyst costs tend to increase, which are undesirable.
[0188] Further, when the hydroisomerization catalyst according to the present aspect is
used for hydroisomerization of a hydrocarbon oil containing many sulfur-containing
compounds and/or nitrogen-containing compounds, from the perspective of the durability
of catalytic activity, it is preferred that the active metals are a combination such
as nickel-cobalt, nickel-molybdenum, cobalt-molybdenum, nickel-molybdenum-cobalt,
or nickel-tungsten-cobalt. It is preferred that the amount of these metals supported
is 0.001 to 50% by mass, and more preferably 0.01 to 30% by mass, based on the mass
of the carrier.
[0189] In the present aspect, it is preferred to calcine the above-described catalyst precursor
so that the organic template remaining in the carrier precursor remains. Specifically,
it is preferred to set the heating conditions so that the micropore volume per unit
mass of the obtained hydroisomerization catalyst is 0.02 to 0.11 cc/g, and the micropore
volume per unit mass of the zeolite that is contained in that catalyst is 0.04 to
0.12 cc/g.
[0190] The micropore volume per unit mass of the hydroisomerization catalyst is calculated
by a method called nitrogen adsorption measurement. Namely, for the catalyst, the
micropore volume per unit mass of the catalyst is calculated by analyzing a physical
adsorption and desorption isotherm of nitrogen measured at the temperature of liquid
nitrogen (-196°C), specifically, analyzing an adsorption isotherm of nitrogen measured
at the temperature of liquid nitrogen (-196°C) by a t-plot method. Further, the micropore
volume per unit mass of the zeolite contained in the catalyst is also calculated by
the above-described nitrogen adsorption measurement.
[0191] In addition, in the present description, a micropore indicates a "pore having a diameter
of 2 nm or less" defined in IUPAC (International Union of Pure and Applied Chemistry).
[0192] A micropore volume V
z per unit mass of the zeolite contained in the catalyst can be calculated, for example,
if the binder does not have a micropore volume, based on the following expression
from a value V
c of the micropore volume per unit mass of the hydroisomerization catalyst and the
content M
z (% by mass) of zeolite in the catalyst.
[0193] It is preferred that, subsequent to the calcination treatment, the hydroisomerization
catalyst of the present aspect is subjected to a reduction treatment after the catalyst
is loaded in the reactor for conducting the hydroisomerization reaction. Specifically,
it is preferred that the hydroisomerization catalyst is subjected to the reduction
treatment for about 0.5 to 5 hours in an atmosphere containing molecular hydrogen,
and preferably under a stream of hydrogen gas, preferably at 250 to 500°C, and more
preferably at 300 to 400°C. By performing this step, it can be further ensured that
high activity for the dewaxing of the hydrocarbon oil can be imparted to the catalyst.
[0194] The hydroisomerization catalyst according to the present aspect is a hydroisomerization
catalyst containing a carrier that includes a zeolite having a one-dimensional, 10-membered
ring pore structure and a binder, and platinum and/or palladium supported on the carrier,
in which the micropore volume per unit mass of the catalyst is 0.02 to 0.11 cc/g.
Further, this zeolite is preferably a zeolite derived from ion-exchanged zeolite obtained
by ion-exchanging an organic template-containing zeolite that contains an organic
template and has a one-dimensional, 10-membered ring pore structure in a solution
containing ammonium ions and/or protons, in which the micropore volume per unit mass
of the zeolite contained in the catalyst is 0.04 to 0.12 cc/g.
[0195] The above-described hydroisomerization catalyst can be produced by the method described
above. The micropore volume per unit mass of the catalyst and the micropore volume
per unit mass of the zeolite contained in the catalyst can be set to be within the
above-described ranges by appropriately adjusting the amount of ion-exchanged zeolite
blended in the mixture including the ion-exchanged zeolite and a binder, the heating
conditions of the mixture in a N
2 atmosphere, and the heating conditions of the catalyst precursor in the atmosphere
containing molecular oxygen.
[0196] The reaction temperature in the dewaxing step is preferably 200 to 450°C, and more
preferably 220 to 400°C. If the reaction temperature is less than 200°C, the isomerization
of the normal paraffins contained in the base oil fraction tends not to easily proceed,
so that the reduction and removal of the wax component tend to be insufficient. Conversely,
if the reaction temperature is more than 450°C, cracking of the base oil fraction
is significant, so that the yield of the lubricant base oil tends to decrease.
[0197] The reaction pressure in the dewaxing step is preferably 0.1 to 20 MPa, and more
preferably 0.5 to 15 MPa. If the reaction pressure is less than 0.1 MPa, catalyst
degradation due to the formation of coke tends to be accelerated. Conversely, if the
reaction pressure is more than 20 MPa, construction costs for the apparatus increase,
so that it tends to become difficult to realize an economical process.
[0198] In the dewaxing step, the liquid hourly space velocity of the base oil fraction based
on the catalyst is preferably 0.01 to 100 hr
-1, and more preferably 0.1 to 50 hr
-1. If the liquid hourly space velocity is less than 0.01 hr
-1, the cracking of the base oil fraction tends to proceed excessively, so that production
efficiency tends to decrease. Conversely, if the liquid hourly space velocity is more
than 100 hr
-1, the isomerization of the normal paraffins contained in the base oil fraction tends
not to proceed easily, so that the reduction and removal of the wax component tend
to be insufficient.
[0199] The supply ratio of hydrogen to base oil fraction is preferably 100 to 1,000 Nm
3/m
3, and more preferably 200 to 800 Nm
3/m
3. If the supply ratio is less than 100 Nm
3/m
3, for example, when the base oil fraction contains sulfur or nitrogen content, hydrogen
sulfide and ammonia gas produced by desulfurization and denitrification reactions
that accompany the isomerization reaction are adsorbed onto and poison the active
metal on the catalyst, which tends to make it difficult to achieve a predetermined
catalytic performance. Conversely, if the supply ratio is more than 1,000 Nm
3/m
3, hydrogen supply equipment having an increased capacity is required, which tends
to make it difficult to realize an economical process.
[0200] The dewaxed oil obtained in the dewaxing step is offered to the fourth step (hydrofinishing
step), and hydrofinishing treatment (hydrorefining treatment) is performed.
[0201] A reactor used in the hydrofinishing step is not particularly limited, and the hydrofinishing
treatment (hydrorefining treatment) can be suitably performed by filling a fixed-bed
flow reactor with a predetermined hydrorefining catalyst and making molecular hydrogen
and the above-described dewaxed oil flow through the reactor. The hydrofinishing treatment
(hydrorefining treatment) described herein means improvement in oxidation stability
and a hue of the lubricant oil, and olefin hydrogenation and aromatic hydrogenation
of the dewaxed oil are performed.
[0202] Examples of the hydrorefining catalyst include catalysts that include a carrier including
one or more inorganic solid acidic substances selected from alumina, silica, zirconia,
titania, boria, magnesia, and phosphorus, and one or more active metals selected from
the group consisting of platinum, palladium, nickel-molybdenum, nickel-tungsten, and
nickel-cobalt-molybdenum that is supported on the carrier.
[0203] A preferred carrier is an inorganic solid acidic substance that includes at least
two or more of alumina, silica, zirconia, or titania.
[0204] As the method for supporting the active metals on the carrier, a conventional method
such as impregnation or ion exchange may be employed.
[0205] The amount of the active metals supported in the hydrorefining catalyst is preferably
such that the total amount of metal is 0.1 to 25% by mass based on the carrier.
[0206] The average pore size of the hydrorefining catalyst is preferably 6 to 60 nm, and
more preferably 7 to 30 nm. If the average pore size is less than 6 nm, a sufficient
catalytic activity tends not to be obtained, while if the average pore size is more
than 60 nm, catalytic activity tends to decrease due to a decrease in the level of
dispersion of the active metals. Further, it is preferred that the pore volume of
the hydrorefining catalyst is 0.2 mL/g or more. If the pore volume is less than 0.2
mL/g, degradation of the activity of the catalyst tends to occur earlier. In addition,
it is preferred that the specific surface area of the hydrorefining catalyst is 200
m
2/g or more. If the specific surface area of the catalyst is less than 200 m
2/g, the dispersibility of the active metals is insufficient, so that activity tends
to decrease. The pore volume and the specific surface area of the catalyst can be
measured and calculated by a BET method using nitrogen adsorption.
[0207] It is preferred that the reaction conditions in the hydrofinishing step are set to
a reaction temperature of 200 to 300°C, a hydrogen partial pressure of 3 to 20 MPa,
an LHSV of 0.5 to 5 h-1, and a hydrogen/oil ratio of 1000 to 5000 scfb, and more preferred
are a reaction temperature of 200°C to 300°C, a hydrogen partial pressure of 4 to
18 MPa, an LHSV of 0.5 to 4 h-1, and a hydrogen/oil ratio of 2000 to 5000 scfb.
[0208] In the present embodiment, it is preferred to adjust the reaction conditions so that
the sulfur and nitrogen content in the hydrorefined oil is 5 ppm by mass or less and
1 ppm by mass or less, respectively.
[0209] The refined oil obtained by the hydrofinishing step is offered to the fifth step
(fractionating step). Then, a desired lubricant oil fraction is obtained by setting
a plurality of cut points and performing vacuum distillation of the hydrorefined oil.
[0210] In addition, the hydrorefined oil may contain light fractions such as naphtha and
kerosene and gas oil produced as a byproduct by the hydroisomerization and the hydrofinishing
treatment (hydrorefining treatment), and these light fractions can be collected as
a fraction having a boiling point of 350°C or less, for example.
[0211] The method for producing a lubricant base oil is not limited to the above-described
aspects and can be appropriately changed. For example, the method for producing a
lubricant base oil of the present invention may include a distillation step of obtaining
a lubricant oil fraction by fractionating the dewaxed oil obtained by the above-described
producing method of the dewaxed oil, and a hydrofinishing step of performing hydrofinishing
treatment (hydrorefining treatment) of the lubricant oil fraction obtained in the
distillation step.
Examples
[0212] Hereinafter, the present invention will be described more specifically based on examples
and comparative examples, but the present invention is not limited to the following
examples.
[Examples 1 to 3 not according to the invention, Comparative Examples 1 and 2]
[0213] In Examples 1 to 3 and Comparative Examples 1 and 2, lubricant base oils shown in
Table 1 were each prepared. The lubricant base oils in Examples 1 to 3 are obtained
based on the method for producing a lubricant base oil according to the above-described
method. In contrast, the lubricant base oils in Comparative Examples 1 and 2 are obtained
by the conventional method for producing a lubricant base oil. Various characteristics
of the respective base oils, and the traction coefficients measured under conditions
of a load of 50 N (average hertz pressure 0.60 GPa), a sample oil temperature of 50°C,
a circumferential velocity of 1 m/s, and a slip ratio of 3%, and using a 27.4 mm steel
ball and a steel disc are shown in Table 1.
[Examples 4 to 6, Comparative Examples 3 to 5]
[0214] In Examples 4 to 6 and Comparative Examples 3 and 4, lubricant oil compositions were
prepared by adding 10% by mass of a package additive (breakdown: 40% by mass of ashless
dispersant, 40% by mass of detergent, 10% by mass of antiwear agent, 8 % by mass of
antioxidant, and 2% by mass of metal deactivating agent) and 5% by mass of a viscosity
index improver (polymethacrylate-based, Mw 350,000, effective concentration 50% by
mass) to the respective lubricant base oils of Examples 1 to 3 or Comparative Examples
1 and 2, respectively. Moreover, as Comparative Example 3, a commercial 0W-20 oil
was prepared. The kinematic viscosities and the viscosity indexes of the respective
lubricant oil compositions are shown in Table 2.
[JC08 Cold Mode Fuel Consumption Evaluation Test]
[0215] With respect to the lubricant oil compositions of Examples 4 to 6, and Comparative
Examples 3 and 4, a JC08 cold mode fuel consumption evaluation test was performed
according to the following procedure.
[0216] JC08 mode is a method for measuring fuel consumption of vehicles, established by
Ministry of Land, Infrastructure, Transport and Tourism (for details, refer to Ministry
of Land, Infrastructure, Transport and Tourism, Announcement that Prescribes Details
of Safety Standards for Road Trucking Vehicles [2009.07.30] Attachment 42 Measurement
Method of Exhaust Gas of Light and Middle Vehicles). JC08 is classified into a cold
mode that starts in an engine cold state and a hot mode that measures fuel consumption
in an engine warm state. In the test, a 2.5 L, FF gasoline engine vehicle (Toyota
ESTIMA) was selected, the engine was washed and filled with a newly-prepared sample
oil before the start of the test, the test vehicle was made to warm up at a constant
rate of 60±2 km/h for 15 minutes or more on a chassis dynamometer, and then, was quickly
returned to the idling state, the vehicle was driven one time in a predetermined running
pattern, and then, was left (soak) in the stopped state in a room of 298+5K (25±5°C)
for 6 hours or more and 36 hours or less, and then, was driven in a predetermined
pattern, and consumed fuel was calculated from driving exhaust gas to determine fuel
consumption. The obtained results are shown in Table 2.
[Table 2]
|
Example 4 |
Example 5 |
Example 6 |
Comparative Example 3 |
Comparative Example 4 |
Comparative Example 5 |
Base oil |
Kind |
Example 1 |
Example 2 |
Example 3 |
Comparative Example 1 |
Comparative Example 2 |
Commercial 0W-20 oil |
Content (% by mass) |
Balance |
Balance |
Balance |
Balance |
Balance |
Package additive (% by mass) |
10 |
10 |
10 |
10 |
10 |
Viscosity index improver (% by mass) |
5 |
5 |
5 |
5 |
5 |
Characteristics of compounded oil (0W-20) |
|
|
|
|
|
|
Kinematic viscosity, mm2/s (40°C) |
32.6 |
35.5 |
36.0 |
33.8 |
36.6 |
38.8 |
Viscosity index |
246 |
230 |
225 |
248 |
222 |
235 |
JC08 cold mode fuel consumption |
|
|
|
|
|
|
Rate of fuel consumption improvement, % |
4.47 |
3.76 |
3.49 |
0.24 |
0.59 |
- |
[Examples 7 and 8, Comparative Examples 6 to 8]
[0217] In Examples 7 and 8 and Comparative Examples 6 to 8, lubricant base oils shown in
Table 3 were each prepared. The lubricant base oils in Examples 7 and 8 are obtained
based on the method for producing a lubricant base oil according to the above-described
method. In contrast, the lubricant base oils in Comparative Examples 6 to 8 are obtained
by the conventional method for producing a lubricant base oil. Various characteristics
of the respective base oils, and the traction coefficients measured under conditions
of a load of 50 N (average hertz pressure 0.60 GPa), a sample oil temperature of 50°C,
a circumferential velocity of 1 m/s, and a slip ratio of 3%, and using a 27.4 mm steel
ball and a steel disc are shown in Table 3.
[Examples 9 and 10, Comparative Examples 9 to 11]
[0218] In Examples 9 and 10 and Comparative Examples 9 to 11, lubricant oil compositions
were prepared by adding 10% by mass of a package additive (breakdown: 40% by mass
of ashless dispersant, 40% by mass of detergent, 10% by mass of antiwear agent, 8%
by mass of antioxidant, and 2% by mass of metal deactivating agent) and 5% by mass
of a viscosity index improver (polymethacrylate-based, Mw 350,000, effective concentration
50% by mass) to the respective lubricant base oils of Examples 7 and 8 and Comparative
Examples 6 to 8, respectively. The kinematic viscosities and the viscosity indexes
of the respective lubricant oil compositions are shown in Table 2.
[JC08 Cold Mode Fuel Consumption Evaluation Test]
[0219] With respect to the lubricant oil compositions of Examples 9, 10, and Comparative
Examples 9 to 11, a JC08 cold mode fuel consumption evaluation test was performed
according to the following procedure.
[0220] JC08 mode is a method for measuring fuel consumption of vehicles, established by
Ministry of Land, Infrastructure, Transport and Tourism (for details, refer to Ministry
of Land, Infrastructure, Transport and Tourism, Announcement that Prescribes Details
of Safety Standards for Road Trucking Vehicles [2009.07.30] Attachment 42 Measurement
Method of Exhaust Gas of Light and Middle Vehicles). JC08 is classified into a cold
mode that starts in an engine cold state and a hot mode that measures fuel consumption
in an engine warm state. In the test, a 2.5 L, FF gasoline engine vehicle (Toyota
ESTIMA) was selected, the engine was washed and filled with a newly-prepared sample
oil before the start of the test, the test vehicle was made to warm up at a constant
rate of 60±2 km/h for 15 minutes or more on a chassis dynamometer, and then, was quickly
returned to the idling state, the vehicle was driven one time in a predetermined running
pattern, and then, was left (soak) in the stopped state in a room of 298±5K (25±5°C)
for 6 hours or more and 36 hours or less, and then, was driven in a predetermined
pattern, and consumed fuel was calculated from driving exhaust gas to determine fuel
consumption.
[0221] The obtained results are shown in Table 4.
[Storage Stability Test]
[0222] With respect to the sample oils of Examples 9, 10, and Comparative Examples 9 to
11, a storage stability test was performed according to the following procedure.
[0223] In a 100 ml screw vial, an oil is charged to two thirds or more thereof, and each
of the test tube is put in a refrigerator of 0±1°C, and the appearance is confirmed
after 48 hours. Without change in the appearance is evaluated as without change, and
generation of condensation is evaluated as condensation.
[0224] The obtained results are shown in Table 4.
[Table 4]
|
Example 9 |
Example 10 |
Comparative Example 9 |
Comparative Example 10 |
Comparative Example 11 |
Base oil |
Kind |
Example 7 |
Example 8 |
Comparative Example 6 |
Comparative Example 7 |
Comparative Example 8 |
Content (% by mass) |
Balance |
Balance |
Balance |
Balance |
Balance |
Package additive (% by mass) |
10 |
10 |
10 |
10 |
10 |
Viscosity index improver (% by mass) |
5 |
5 |
5 |
5 |
5 |
Characteristics of compounded oil (5W-30) |
|
|
|
|
|
Kinematic viscosity, mm2/s (100°C) |
10.4 |
10.3 |
10.3 |
9.95 |
9.97 |
Viscosity index |
255 |
250 |
252 |
245 |
238 |
JC08 cold mode fuel consumption |
|
|
|
|
|
Rate of fuel consumption improvement, % |
4.5 |
4.2 |
0.3 |
0.22 |
0.15 |
Storage stability (0°C) |
Without change |
Without change |
Condensation |
Condensation |
Condensation |
[Examples 11 to 13, Comparative Examples 12 to 14]
[0225] In Examples 11 to 13 and Comparative Examples 12 to 14, lubricant base oils shown
in Table 5 were each prepared. The lubricant base oils in Examples 11 to 13 are obtained
based on the method for producing a lubricant base oil according to the above-described
method. In contrast, the lubricant base oils in Comparative Examples 12 to 14 are
obtained by the conventional method for producing a lubricant base oil. Various characteristics
of the respective base oils, and the traction coefficients measured under conditions
of a load of 50 N (average hertz pressure 0.60 GPa), a sample oil temperature of 50°C,
a circumferential velocity of 1 m/s, and a slip ratio of 3%, and using a 27.4 mm steel
ball and a steel disc are shown in Table 1.
[Examples 14 to 16, Comparative Examples 15 to 17]
[0226] Lubricant oil compositions were prepared by adding 8% by mass of a package additive
(breakdown: antiwear agent: 12% by mass, ashless dispersant: 50% by mass, pour-point
depressant: 1% by mass, antioxidant: 12% by mass, detergent: 25% by mass) and 5% by
mass of a viscosity index improver (polymethacrylate-based, Mw 350,000, effective
concentration 50%) to the respective lubricant base oils. The SBV viscosities of the
respective lubricant oil compositions at -40°C are shown in Table 6.
[SRV Friction Test]
[0227] With respect to the lubricant oil compositions of Examples 14 to 16, and Comparative
Examples 15 to 17, an SRV friction test was performed using an SRV friction tester
at a temperature of -30°C, a load of 50 N, a frequency of 10 Hz, and an amplitude
of 1 mm, and a friction coefficient was measured. The obtained results are shown in
Table 6.
[Table 6]
|
Example 14 |
Example 15 |
Example 16 |
Comparative Example 15 |
Comparative Example 16 |
Comparative Example 17 |
Base oil |
Kind |
Example 11 |
Example 12 |
Example 13 |
Comparative Example 12 |
Comparative Example 13 |
Comparative Example 14 |
Content (% by mass) |
Balance |
Balance |
Balance |
Balance |
Balance |
|
Package additive (% by mass) |
8 |
8 |
8 |
8 |
8 |
8 |
Viscosity index improver (% by mass) |
5 |
5 |
5 |
5 |
5 |
5 |
Characteristics of compounded oil SBV viscosity, mPa·s (-40°C) |
340,000 |
16,000 |
5,800 |
>1,000,000 |
4,020 |
2,600 |
SRV friction test |
|
|
|
|
|
|
Friction coefficient |
0.108 |
0.121 |
0.128 |
Friction coefficient abnormal |
0.155 |
0.165 |