FP11-0670-00
DESCRIPTION
Title of Invention: HYDROCARBON FUEL PRODUCTION
METHOD
5
Technical Field
[0001] The present invention relates to a method for producing a
hydrocarbon fuel.
10 Background Art
[0002] In recent years, with an increase in environmental awareness,
attempts have been actively made to positively utilize biomass, carbon
neutral resources, as energy sources, instead of fossil fuels, in order to
reduce the amount of carbon dioxide discharged. Among them, a
15 method of culturing algae, such as Chlorella, that produce an aliphatic
compound, such as an oil or fat or an aliphatic hydrocarbon, and
recovering the aliphatic compound from the algae to provide a
hydrocarbon fuel is regarded as promising (see Non Patent Literatures 1
and 2).
20 [0003] As the above method of recovering an aliphatic compound from
algae, a solvent extraction method is widely used in which using a
solvent in which the solubility of aliphatic compounds is high, such as
hexane or ethyl acetate, extraction is performed under atmospheric
pressure at a temperature equal to or lower than the boiling point of the
25 solvent. On the other hand, an aliphatic compound produced by algae
has disadvantages, for example, it is poor in flowability because it is a
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linear molecule, and when the aliphatic compound is an oil or fat, the
content of oxygen is high, and there is a fear of adversely affecting the
material of an engine, and the aliphatic compound is of low quality as a
fuel as it is. Therefore, in order to obtain a high quality fuel from an
5 aliphatic compound that algae produce, it is necessary to convert the
structure of the above aliphatic compound, such as the removal of
oxygen, the lowering of molecular weight, or the introduction of a
branched chain, by performing hydrotreatment, such as
hydrodeoxygenation treatment, hydrocracking treatment, or
10 hydroisomerization treatment, on the above aliphatic compound using a
catalyst.
Citation List
Non Patent Literature
15 [0004] Non Patent Literature 1: "Bisaisorui No Riyo (Use of
Microalgae)" edited by Katsumi Yamaguchi, KOUSEISHA
KOUSEDCAKU Co., Ltd., 1992, pp. 64-74
Non Patent Literature 2: Masaki Ota, PETROTECH, 2010, pp.
96-100
20
Summary of Invention
Technical Problem
[0005] However, when an aliphatic compound recovered from algae by
the above solvent extraction method is subjected to hydrotreatment
25 using a catalyst, a problem is that the catalyst is rapidly deactivated in a
treatment step, and long hours of continuous operation cannot be
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performed. In other words, in the method, hydrotreatment cannot be
commercially stably performed, which is a large obstacle in producing a
high quality hydrocarbon fuel from an aliphatic compound produced by
algae.
5 [0006] The present invention has been made in view of such
circumstances, and it is an object of the present invention to provide a
method for producing a hydrocarbon fuel in which a high quality
hydrocarbon fuel can be commercially stably produced from an
aliphatic compound produced by algae.
10
Solution to Problem
[0007] In order to solve the above problem, the present invention
provides a method for producing a hydrocarbon fuel, comprising a first
step of holding a mixture containing an aliphatic compound produced
15 by algae, and a hydrocarbon solvent in which critical temperature is
90°C or higher, in a supercritical state, with temperature and pressure
adjusted so that a solubility of the aliphatic compound in the
hydrocarbon solvent is 15 g or less per 100 g of the hydrocarbon solvent,
and then recovering a soluble portion of the aliphatic compound in the
20 hydrocarbon solvent; and a second step of subjecting the soluble portion
recovered in the first step to hydrotreatment using a catalyst.
[0008] The method for producing a hydrocarbon fuel according to the
present invention has the above configuration, and therefore has an
effect that the deactivation of the catalyst can be sufficiently suppressed
25 in the hydrotreatment in the second step, and a high quality hydrocarbon
fuel can be commercially stably produced.
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[0009] The present inventors presume a reason why the above effect is
achieved by the present invention as follows.
First, in the conventional solvent extraction method using a
solvent in which the solubility of aliphatic compounds is high, such as
5 hexane or ethyl acetate, metals, such as magnesium (Mg) and sodium
(Na), in a recovered aliphatic compound are mixed as impurities. It is
considered that these metals are derived from algae. Then, it is
considered that when such an aliphatic compound comprising metals is
subjected to a hydrotreatment step, a catalyst is poisoned by the metals,
10 and the catalyst is rapidly deactivated.
On the other hand, in the method for producing a hydrocarbon
fuel according to the present invention, by holding a mixture comprising
an aliphatic compound produced by algae, and a hydrocarbon solvent in
which critical temperature is 90°C or higher, in a supercritical state,
15 with temperature and pressure adjusted so that the solubility of the
aliphatic compound in the hydrocarbon solvent is 15 g or less per 100 g
of the hydrocarbon solvent, and then recovering the soluble portion of
the aliphatic compound in the hydrocarbon solvent, the mixing of
metals into the recovered aliphatic compound can be sufficiently
20 suppressed. Then, it is presumed that by subjecting the aliphatic
compound recovered in this manner to a hydrotreatment step, the
poisoning and deactivation of the catalyst by metals can be sufficiently
suppressed.
[0010] In the method for producing a hydrocarbon fuel according to the
25 present invention, it is preferred that the above algae comprise at least
one selected from the group consisting of the genus Chlorella, the genus
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Scenedesmus, the genus Arthrospira, the genus Euglena, the genus
Botryococcus, and the genus Pseudochoricystis.
Advantageous Effects of Invention
5 [0011] According to the present invention, a method for producing a
hydrocarbon fuel in which a high quality hydrocarbon fuel can be
commercially stably produced from an aliphatic compound recovered
from algae is provided.
10 Brief Description of Drawings
[0012] [Figure 1] Figure 1 is an explanatory view showing one example
of a production apparatus preferably used in a method for producing a
hydrocarbon fuel according to the present invention.
15 Description of Embodiments
[0013] A preferred embodiment of the present invention (hereinafter
sometimes referred to as "this embodiment") will be described in detail
below.
[0014] A method for producing a hydrocarbon fuel according to this
20 embodiment comprises the first step of holding a mixture containing an
aliphatic compound produced by algae and a hydrocarbon solvent in
which critical temperature is 90°C or higher with temperature and
pressure adjusted at a temperature equal to or higher than the critical
temperature of the hydrocarbon solvent so that the solubility of the
25 aliphatic compound in the hydrocarbon solvent is 15 g or less per 100 g
of the hydrocarbon solvent, and then recovering the soluble portion of
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the aliphatic compound in the hydrocarbon solvent; and the second step
of subjecting the soluble portion recovered in the first step to
hydrotreatment using a catalyst.
[0015] At a temperature at which the mixture of an aliphatic compound
5 produced by algae and a hydrocarbon solvent in which critical
temperature is 90°C or higher is held, lower than the critical temperature
of the hydrocarbon solvent, it is difficult to obtain the effect of the
present invention. In addition, if the solubility of the aliphatic
compound in the hydrocarbon solvent at the holding temperature of the
10 mixture is more than 15 g per 100 g of the hydrocarbon solvent, it is
difficult to obtain the effect of the present invention. The solubility of
the aliphatic compound in the hydrocarbon solvent at the above holding
temperature is preferably 10 g or less, particularly preferably 6 g or less,
per 100 g of the hydrocarbon solvent. In addition, in terms of
15 treatment efficiency (the recovery efficiency of a purified aliphatic
compound), the solubility of the aliphatic compound in the hydrocarbon
solvent at the above holding temperature is preferably 1 g or more per
100 g of the hydrocarbon solvent.
[0016] Oils and fats, aliphatic hydrocarbons, and the like are included
20 in aliphatic compounds produced by algae, which are raw materials of
hydrocarbon fuels. In addition, algae that produce aliphatic
compounds refer to organisms (algae) living in water that perform
oxygenic photosynthesis, the organisms producing aliphatic compounds
in their bodies. Algae have the property of immobilizing carbon
25 dioxide by photosynthesis and converting it to aliphatic compounds.
Any algae can be used in a method for producing an aliphatic
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f
compound in this embodiment as long as they are algae having such a
property.
[0017] Examples of algae that produce aliphatic compounds in this
embodiment include algae belonging to the genus Chlorella, the genus
5 Scenedesmus, the genus Arthrospira, the genus Euglena, the genus
Botryococcus, and the genus Pseudochoricystis. More specific
examples may include Chlorella, Scenedesmus, Spirulina, Euglena,
Botryococcus braunii, and Pseudochoricystis ellipsoidea. However,
the algae are not limited to these as long as they produce aliphatic
10 compounds.
[0018] For example, Chlorella, Scenedesmus, Spirulina, and Euglena
produce oils and fats, and Botryococcus braunii and Pseudochoricystis
ellipsoidea produce aliphatic hydrocarbons. These aliphatic
compounds are usually accumulated in the cells of the algae (alga
15 bodies), and part of the aliphatic compounds accumulated in the cells
may be discharged out of the cells in a culture step.
[0019] Examples of oils and fats produced by cultured algae include
aliphatic ester compounds composed of aliphatic carboxylic acids and
monohydric or trihydric aliphatic alcohols. These oils and fats are not
20 particularly limited as long as they are produced by algae, and examples
thereof may include methyl laurate, myristyl myristate, and methyl
palmitate.
[0020] Examples of aliphatic hydrocarbons produced by cultured algae
include aliphatic hydrocarbons being solid or liquid at room temperature,
25 composed of carbon atoms and hydrogen atoms, for example, saturated
or unsaturated aliphatic hydrocarbons having 15 to 40 carbon atoms,
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particularly linear aliphatic hydrocarbons. The aliphatic hydrocarbons
are not particularly limited as long as they are produced by algae, and
examples thereof may include n-heptadecene and n-eicosadiene.
[0021] In a culture step in this embodiment, culture can be performed
5 under known culture conditions for respective algae. Usually, culture
is performed at room temperature, preferably at 25 to 37°C, by
photoautotrophic culture in which algae are multiplied by
photosynthesis using carbon dioxide in air as a carbon source. For a
light source for the photosynthesis, sunlight or an artificial light source
10 can be used. In order to hasten the multiplication of the algae, light
irradiation for the algae is preferably performed at 2 to 100 kilolux for
30 to 500 hours. Carbon dioxide concentration in a medium
atmosphere is preferably 0.3 to 10% by volume, and in order to promote
the dissolution of carbon dioxide in a medium, the medium may be
15 stirred, or aerated with air, as required.
[0022] For the medium, general inorganic media, such as CHU media,
JM media, and MDM media, can be used. Usually, Ca(N03)2-4H20
and KN03 as nitrogen sources, and KH2P04, MgS04-7H20, and the like
as other main nutritional components are contained in inorganic media.
20 In addition, an antibiotic that does not affect the growth of the algae,
and the like may be added to the medium. The pH of the medium is
preferably 3 to 10. A culture period is preferably 1 to 20 days when
culture is started at an alga body concentration of 0.5 g/L though the
culture period also depends on the amount of alga bodies inoculated
25 first. If the culture period is less than 1 day, there is a tendency that a
sufficient amount of alga bodies are difficult to obtain, and if the culture
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§
period is more than 20 days, there is a tendency that nutrients in the
medium are depleted and the growth of the algae is difficult.
[0023] Alga body concentration in the medium after the completion of
the culture is different depending on the type of algae and culture
5 conditions, and is usually 0.01 to 3% by mass. When an aliphatic
compound is mixed with a hydrocarbon solvent in which critical
temperature is 90°C or higher, a medium containing the aliphatic
compound after the completion of culture may be used as it is, or one in
which the concentration of alga bodies is performed by subjecting the
10 medium to centrifugation or the like may be used. The concentration
of the alga bodies when concentration is performed is usually 1 to 30%
by weight. Further, dry alga bodies containing the aliphatic compound,
obtained by drying the medium or its concentrated liquid can also be
used.
15 [0024] In addition, it is also possible to use an oil containing an
aliphatic compound produced by algae, extracted from alga bodies by a
solvent extraction method in which using a solvent in which the
solubility of aliphatic compounds is high, such as hexane or ethyl
acetate, extraction is performed under atmospheric pressure at a
20 temperature equal to or lower than the boiling point of the solvent, as
required.
[0025] It is also possible to perform the step of increasing the
concentration of the aliphatic compound in the alga bodies as an
intermediate step as required. Examples of a specific operation of this
25 step may include an operation in which the medium comprising the alga
bodies obtained by the culture step, or its concentrated liquid is placed
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in an anaerobic state.
[0026] As the hydrocarbon solvent in which critical temperature is
90°C or higher, aliphatic hydrocarbons having 3 to 6 carbon atoms are
preferred, and specific examples thereof may include propane, n-butane,
5 isobutane, n-pentane, and n-hexane. Among these, propane, n-butane,
and isobutane are more preferred, and propane is particularly preferred.
The critical temperature and critical pressure of hydrocarbon solvents
are shown in Table 1.
[0027]
10 [Table 1]
Substance name
Ethane
Propane
Normal butane
Isobutane
Normal pentane
Normal hexane
Normal heptane
Chemical
formula
C2H4
C3H8
n-GjHio
i-C4Hio
n-CsHn
n-CeHi4
n-C7Hi6
Critical
temperature
TC[K]
282.9
370.0
425.2
408.1
469.6
507.4
540.2
Critical
temperature
TC [°C]
9.7
96.8
152.0
134.9
196.4
234.2
267.0
Critical
pressure
PC [MPa]
5.117
4.256
3.80
3.65
3.37
2.97
2.74
[0028] As a method for recovering the soluble portion of the aliphatic
compound in the hydrocarbon solvent, for example, gravity
sedimentation can be used.
15 [0029] The soluble portion recovered in the first step is subjected to
hydrotreatment using a catalyst. The hydrotreatment using a catalyst
means performing at least one treatment of hydrodeoxygenation
treatment, hydrocracking treatment, and hydroisomerization treatment,
using a catalyst.
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•I
[0030] In hydrodeoxygenation treatment, an oxygen atom contained in
a raw material, which is feared to adversely affect the material of an
engine, is removed as water and/or an alcohol, and the like, and an
unsaturated bond in the raw material is hydrogenated to convert the raw
5 material to a saturated aliphatic hydrocarbon. A hydrocarbon fuel
substantially comprising no oxygen atom or unsaturated bond without
fear of engine damage or the like can be obtained by this
hydrodeoxygenation treatment.
[0031] When the aliphatic compound is an oil or fat (an ester composed
10 of a fatty acid and glycerin), it is preferred to perform
hydrodeoxygenation treatment first and remove oxygen atoms because
the oil or fat comprises many oxygen atoms in its molecule. At the
same time, when the oil or fat has an unsaturated bond in its molecule,
this unsaturated bond is hydrogenated and a linear saturated
15 hydrocarbon (normal paraffin) is produced during the
hydrodeoxygenation treatment.
[0032] In this hydrodeoxygenation treatment, when the catalyst used
also has hydrocracking activity and/or hydroisomerization activity, there
are cases where in a produced normal paraffin, at least part of it
20 undergoes hydrocracking and is converted to a normal paraffin having
fewer carbon atoms by the action of the catalyst. In addition, there are
cases where at least part of a normal paraffin undergoes
hydroisomerization and is converted to a branched saturated
hydrocarbon (isoparaffin) by the action of the catalyst.
25 [0033] In hydrocracking treatment, a saturated or unsaturated aliphatic
hydrocarbon is converted to an aliphatic hydrocarbon having fewer
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carbon atoms. In this hydrocracking treatment, it is general that not
only a hydrocracking reaction but also a hydroisomerization reaction
concurs by the action of the catalyst used. Therefore, it is general that
a product in the hydrocracking treatment has a lower molecular weight
5 than an aliphatic hydrocarbon that is a raw material in the treatment, and
at the same time, at least part of it becomes an isoparaffin having a
branched chain structure.
[0034] When the aliphatic compound is a linear aliphatic hydrocarbon,
the linear aliphatic hydrocarbon is wax-like at room temperature as it is,
10 and its use as a liquid fuel is difficult in many cases. In addition, even
if this linear aliphatic hydrocarbon is liquid at room temperature, it is
poor in flowability at low temperature. Therefore, it is preferred to
convert the linear aliphatic hydrocarbon to a hydrocarbon having a
smaller number of carbon atoms by hydrocracking treatment and
15 convert at least part of it to a branched structure by concurring
hydroisomerization to be liquid at room temperature and improve
flowability at low temperature. In addition, when the linear aliphatic
hydrocarbon as the aliphatic compound has an unsaturated bond, the
unsaturated bond is hydrogenated and the linear aliphatic hydrocarbon
20 is converted to a saturated hydrocarbon in the process of hydrocracking
treatment.
[0035] In addition, when the above aliphatic compound is an oil or fat,
and hydrocracking and/or hydroisomerization does not proceed
sufficiently in parallel with hydrodeoxygenation in the process of
25 converting the oil or fat to a saturated aliphatic hydrocarbon by
hydrodeoxygenation treatment, there are cases where the produced
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saturated aliphatic hydrocarbon is solid at room temperature, and there
are cases where even if the produced saturated aliphatic hydrocarbon is
liquid at room temperature, low temperature flowability is not sufficient.
In such cases, by subjecting the obtained saturated aliphatic
5 hydrocarbon to hydrocracking treatment, a liquid hydrocarbon fuel that
is liquid at room temperature and excellent in low temperature
flowability can be obtained. The obtained hydrocracked product is
fractionated into fractions in boiling point ranges by means such as
distillation as required. The fractionated aliphatic hydrocarbons are
10 used in applications suitable for respective fractionated aliphatic
hydrocarbons as base materials for gasoline engines, heating (kerosene),
jet engines, diesel engines, and the like.
[0036] In hydroisomerization treatment, part or all of a linear aliphatic
hydrocarbon is converted to a branched aliphatic hydrocarbon
15 (isoparaffin). A liquid fuel base material having high flowability even
at the time of low temperature can be obtained by this treatment.
[0037] When the aliphatic compound is a linear aliphatic hydrocarbon
and the low temperature flowability of a product obtained by subjecting
the hydrocarbon to the above hydrocracking treatment is not sufficient,
20 when the number of carbon atoms of a linear aliphatic hydrocarbon that
is the aliphatic compound is relatively small, when the aliphatic
hydrocarbon is an oil or fat and the low temperature flowability of a
saturated aliphatic hydrocarbon obtained by hydrodeoxygenation
treatment is not sufficient, or the like, hydroisomerization treatment can
25 be performed.
[0038] A fuel base material obtained in this manner is preferably used
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for jet engines and diesel engines.
[0039] The hydrodeoxygenation treatment, the hydrocracking treatment,
and the hydroisomerization treatment will each be described below in
detail.
5 [0040] As the catalyst used in the hydrodeoxygenation treatment, for
example, catalysts used in the hydrodeoxygenation treatment of oils and
fats derived from animals and plants disclosed in Japanese Unexamined
Patent Application Publication No. 2010-121071, Japanese Unexamined
Patent Application Publication No. 2007-308564, Japanese Unexamined
10 Patent Application Publication No. 2007-308565, and the like can be
used. In other words, a catalyst in which at least one metal having
hydrogenation activity (active metal) selected from elements in Groups
6 and 8 to 10 of the periodic table is supported on a support composed
of a porous inorganic oxide comprising at least one element selected
15 from aluminum, silicon, zirconium, boron, titanium, and magnesium
can be used. Here, the "periodic table" means the long-form periodic
table of elements defined by IUPAC (International Union of Pure and
Applied Chemistry).
[0041] Examples of the above support include alumina, silica, zirconia,
20 boria, titania, or magnesia, or a complex oxide formed by combining
these, silica-alumina, silica-zirconia, alumina-boria, silica-titania, or
silica-magnesia. Among these, silica-alumina, silica-zirconia,
alumina-boria, silica-titania, and silica-magnesia, which are complex
oxides, and the like are preferred. In addition, the above support may
25 comprise a zeolite.
The above support may contain a binder, such as alumina, silica,
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titania, or magnesia, for the purpose of improving moldability and
mechanical strength.
[0042] As the above active metal, preferred examples of metals in
Group 6 include molybdenum (Mo) and tungsten (W), preferred
5 examples of metals in Group 8 include ruthenium (Ru) and osmium
(Os), preferred examples of metals in Group 9 include cobalt (Co),
rhodium (Rh), and iridium (Ir), and preferred examples of metals in
Group 10 include nickel (Ni), palladium (Pd), and platinum (Pt). One
of these metals may be used alone, or two or more of these metals may
10 be used in combination. Preferred examples in which two or more are
used in combination include combinations such as Ni-Mo, Co-Mo,
Ni-Co-Mo, and Ni-W. In the above combinations of metals, it is
preferred to pretreat (presulfurize) the catalyst with a fluid comprising a
sulfur compound, such as dimethyl disulfide, before subjecting the
15 catalyst to hydrodeoxygenation treatment because the metals exhibit
hydrogenation activity by being sulfurized, and it is preferred to add a
small amount of the sulfur compound to a raw material oil also during
the treatment.
[0043] On the other hand, when one is used alone as the active metal,
20 precious metals, such as Pt, Pd, and Rh, are preferred. When a
precious metal is used as the active metal, it is general to perform no
presulfurization and perform reduction treatment with a hydrogen gas or
the like and subject the catalyst to hydrodeoxygenation treatment
because precious metals are poisoned by sulfur compounds. Also
25 when precious metals are used as the active metals, two or more, for
example, Pt-Pd, may be used in combination.
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[0044] It is preferred that the amount of the above active metal
supported based on the total mass of the support is 0.1 to 3% by mass as
metal atoms when the active metal is a precious metal, and the amount
of the above active metal supported is 2 to 50% by mass as a metal
5 oxide when the active metal is a metal other than precious metals.
[0045] A method for supporting the active metal on the support is not
particularly limited, and known methods applied when usual
hydrodesulfurization catalysts and the like are produced can be used.
Usually, a method of impregnating a catalyst support with a solution
10 comprising a salt of an active metal is preferably used. In addition, an
equilibrium adsorption method, a Pore-filling method, an
Incipient-wetness method, and the like are also preferably used. For
example, the Pore-filling method is a method of previously measuring
the pore volume of a support and impregnating with a metal salt
15 solution of the same volume as the pore volume, and an impregnation
method is not particularly limited, and impregnation can be performed
by an appropriate method according to the amount of a metal supported
and the physical properties of a catalyst support.
[0046] The reactor form of the hydrodeoxygenation treatment may be a
20 fixed bed type. In other words, hydrogen can take either form of a
countercurrent or a cocurrent with respect to a raw material oil, and a
form having a plurality of reaction columns and combining a
countercurrent and a cocurrent may be used. A general form is a
downflow, and a gas-liquid cocurrent form can be used. In addition, a
25 reactor may be used alone, or a plurality of reactors may be combined,
and a structure in which the interior of one reactor is divided into a
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c
plurality of catalyst beds may be used.
[0047] As treatment conditions in the hydrodeoxygenation treatment, it
is preferred that hydrogen pressure is 2 to 13 MPa, liquid space velocity
is 0.1 to 3.0 h"1, and hydrogen/oil ratio is 150 to 1500 NL/L, it is more
5 preferred that hydrogen pressure is 2 to 13 MPa, liquid space velocity is
0.1 to 3.0 h"1, and hydrogen/oil ratio is 150 to 1500 NL/L, and
conditions in which hydrogen pressure is 3 to 10.5 MPa, liquid space
velocity is 0.25 to 1.0 h"1, and hydrogen/oil ratio is 300 to 1000 NL/L
are particularly preferred.
10 [0048] In addition, treatment temperature is generally preferably in the
range of 150 to 480°C, desirably 200 to 400°C, and further desirably in
the range of 260 to 360°C, as the average temperature of the entire
reactor. If reaction temperature is lower than 150°C, a reaction may
not proceed sufficiently, and if the reaction temperature is higher than
15 480°C, there is a tendency that decomposition proceeds excessively,
causing a decrease in product yield.
[0049] The hydrodeoxygenation treatment involves the generation of
large heat of reaction, and therefore, it is preferably performed to take
means for preventing an excessive increase in temperature in the reactor.
20 For example, a method is used such as dividing a hydrogen gas into a
plurality of flows and feeding the hydrogen gas to the middle of the
reactor, rather than feeding all of the hydrogen gas to a reactor inlet, to
cool the interior of the reactor by the cold heat of the hydrogen gas, or
recycling part of a produced oil flowed out of the reactor to the reactor
25 to dilute a raw material oil.
[0050] As the catalyst used in the hydrocracking treatment, known
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fwt
catalysts used in the hydrocracking treatment of hydrocarbons
comprising wax components can be used. In other words, examples
thereof include those in which metals belonging to Groups 8 to 10 of the
periodic table as active metals are supported on supports comprising
5 solid acids.
[0051] Examples of preferred supports include those comprising one or
more types of solid acids selected from among crystalline zeolites, such
as ultrastable Y-type (USY) zeolites, Y-type zeolites, mordenites, and
beta zeolites, and amorphous complex metal oxides having fire
10 resistance, such as silica-alumina, silica-zirconia, and alumina-boria.
Further, the support is more preferably one comprising a USY zeolite
and one or more solid acids selected from among silica-alumina,
alumina-boria, and silica-zirconia, further preferably one comprising a
USY zeolite and alumina-boria and/or silica-alumina.
15 [0052] USY zeolites are those in which Y-type zeolites are
ultrastabilized by hydrothermal treatment and/or acid treatment, and in
addition to a fine pore structure referred to as micropores in which pore
diameter that the Y-type zeolites intrinsically have is 2 nm or less, new
pores having a pore diameter in the range of 2 to 10 nm are formed.
20 There is no particular limit to the average particle diameter of the USY
zeolite, and the average particle diameter of the USY zeolite is
preferably 1.0 um or less, more preferably 0.5 um or less. In addition,
in the USY zeolites, silica/alumina molar ratio (the molar ratio of silica
to alumina) is preferably 10 to 200, more preferably 15 to 100, and
25 further preferably 20 to 60.
[0053] In addition, it is preferred that the support comprises 0.1 to 80%
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by mass of a crystalline zeolite and 0.1 to 60% by mass of an
amorphous complex metal oxide having fire resistance.
[0054] The support can be produced by molding a support composition
comprising the above solid acid, and a binder as required, and then
5 firing the molded support composition. The blending proportion of the
solid acid is preferably 1 to 70% by mass, more preferably 2 to 60% by
mass, based on the total amount of the support. In addition, when the
support comprises a USY zeolite, the blending proportion of the USY
zeolite is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by
10 mass, based on the mass of the entire support. Further, when the
support comprises a USY zeolite and alumina-boria, the blending ratio
of the USY zeolite to the alumina-boria (USY zeolite/alumina-boria) is
preferably 0.03 to 1 in terms of mass ratio. In addition, when the
support comprises a USY zeolite and silica-alumina, the blending ratio
15 of the USY zeolite to the silica-alumina (USY zeolite/ silica-alumina) is
preferably 0.03 to 1 in terms of mass ratio.
[0055] As the binder, there is no particular limit, and alumina, silica,
titania, and magnesia are preferred, and alumina is more preferred.
The amount of the binder blended is preferably 20 to 98% by mass,
20 more preferably 30 to 96% by mass, based on the mass of the entire
support.
[0056] The shape of a molded support is not limited, and examples
thereof include a spherical shape, a cylindrical shape, and an irregular
cylindrical shape having a trefoil or quatrefoil cross section. In
25 addition, there is also no particular limit to its particle diameter, and the
particle diameter is preferably 1 urn to 10 mm in terms of practicality.
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[0057] The firing temperature of the above support composition is
preferably in the range of 400 to 550°C, more preferably in the range of
470 to 530°C, and further preferably in the range of 490 to 530°C.
[0058] Specific examples of the metals in Groups 8 to 10 of the
5 periodic table include cobalt, nickel, rhodium, palladium, iridium, and
platinum. Among these, it is preferred to use one of metals selected
from nickel, palladium, and platinum alone or two or more of the metals
in combination. These metals can be supported on the
above-described support by conventional methods, such as
10 impregnation and ion exchange. There is no particular limit to the
amount of the metals supported, and the total amount of the metals is
preferably 0.1 to 3.0% by mass based on the mass of the support.
[0059] The form of a reactor and treatment conditions for performing
the hydrocracking treatment are similar to those of the above-described
15 hydrodeoxygenation treatment, and therefore, description is omitted in
terms of avoiding repetition. An excessive increase in temperature in
the reactor due to the heat of reaction mentioned in the
hydrodeoxygenation treatment does not apply to the hydrocracking
treatment and the hydroisomerization treatment described later.
20 [0060] As the catalyst used in the hydroisomerization treatment,
catalysts generally used in hydroisomerization in petroleum refining and
the like, that is, catalysts in which active metals having hydrogenation
ability are supported on inorganic supports, can be used.
[0061] Examples of the inorganic support constituting the above
25 catalyst include metal oxides, such as alumina, silica, titania, zirconia,
and boria. One of these metal oxides, a mixture of two or more of
20
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m
these metal oxides, or a complex metal oxide, such as silica-alumina,
silica-zirconia, alumina-zirconia, or alumina-boria, may be used. The
above inorganic support is preferably a complex metal oxide having
solid acidity, such as silica-alumina, silica-zirconia, alumina-zirconia, or
5 alumina-boria, in terms of allowing hydroisomerization to proceed
efficiently. In addition, a small amount of a zeolite may be contained
in the inorganic support.
[0062] Further, a binder may be blended in the above inorganic support
for the purpose of an improvement in the moldability and mechanical
10 strength of the support. Examples of preferred binders include
alumina, silica, and magnesia.
[0063] As the active metal constituting the above catalyst, one or more
metals selected from the group consisting of metals in Groups 8 to 10
are used. Specific examples of these metals include a precious metal,
15 such as platinum, palladium, rhodium, ruthenium, iridium, or osmium,
or cobalt or nickel, preferably platinum, palladium, nickel, or cobalt,
and further preferably platinum or palladium. In addition, it is also
preferred to use a plurality of these metals in combination, and
examples of preferred combinations in this case include
20 platinum-palladium.
[0064] The content of the active metal in the above catalyst is
preferably about 0.1 to 3% by mass as metal atoms based on the mass of
the support when the active metal is the above precious metal. In
addition, the content of the active metal in the above catalyst is
25 preferably about 2 to 50% by mass as a metal oxide based on the mass
of the support when the active metal is a metal other than the above
21
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precious metals.
[0065] The form of a reactor and treatment conditions for performing
the hydroisomerization treatment are similar to those of the
above-described hydrocracking treatment, and therefore, description is
5 omitted in terms of avoiding repetition.
[0066] For the hydrodeoxygenation treatment, hydrocracking treatment,
and hydroisomerization treatment described above, it is possible to
provide different steps, respectively, and perform these, or it is possible
to simultaneously perform a plurality of treatments by using a catalyst
10 having a plurality of functions in one step. Particularly, when the
hydrocracking treatment is performed, it is usual that not only the
decomposition of molecules constituting a raw material oil, but also the
provision of a branched chain by hydroisomerization proceeds
simultaneously. In addition, it is possible to provide a plurality of
15 different catalyst beds in one reactor and perform different treatments in
the respective catalyst beds.
[0067] A high quality hydrocarbon fuel can be commercially stably
produced from an aliphatic compound produced by algae, by using as
essential steps the first step of obtaining a mixture comprising an
20 aliphatic compound, such as an oil or fat or an aliphatic hydrocarbon,
produced by algae and a hydrocarbon solvent in which critical
temperature is 90°C or higher, adjusting, for the mixture, temperature
and pressure at a temperature equal to or higher than the critical
temperature of the hydrocarbon solvent so that the solubility of the
25 aliphatic compound in the hydrocarbon solvent is 15 g or less per 100 g
of the hydrocarbon solvent, and recovering the soluble portion of the
22
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aliphatic compound in the hydrocarbon; and the second step of
subjecting the soluble portion obtained in the first step to
hydrotreatment using a catalyst, as described above.
[0068] Next, one example of a production apparatus preferably used in
5 this embodiment will be described with reference to Figure 1.
[0069] In a production apparatus shown in Figure 1, an aliphatic
compound extraction and separation vessel 1, a solvent separation
vessel 2, and a hydrotreatment reactor 3 are disposed in this order from
an upstream side. The aliphatic compound extraction and separation
10 vessel 1 and the solvent separation vessel 2 are coupled to each other
via a line L4, and the solvent separation vessel 2 and the hydrotreatment
reactor 3 are coupled to each other via lines L6 and L7.
[0070] A line LI is coupled to the upstream side of the aliphatic
compound extraction and separation vessel 1, and a pump 11, a mixing
15 apparatus 12, and a temperature adjustment apparatus 13 are provided in
the line LI in this order from the upstream side. A plunger pump can
be illustrated as the pump 11, a line mixer can be illustrated as the
mixing apparatus 12, and a heater using steam can be illustrated as the
temperature adjustment apparatus 13.
20 [0071] In addition, the top of the solvent separation vessel 2 and a
predetermined position between the pump 11 and the mixer 12 in the
line LI are coupled to each other via a line L2. A pressure adjustment
valve V2 and a pressure/flow rate adjustment apparatus 14 are provided
in the line L2. Thus, a hydrocarbon solvent in which critical
25 temperature is 90°C or higher (or a mixed fluid comprising the
hydrocarbon solvent) separated in the solvent separation vessel 2 can be
23
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adjusted to a predetermined pressure and flow rate and transferred to the
line LI. A booster can be illustrated as the pressure/flow rate
adjustment apparatus 14. Further, a line L3 for introducing a
hydrocarbon solvent in which critical temperature is 90°C or higher, as
5 a makeup gas, is coupled to the line L2.
[0072] In the production apparatus shown in Figure 1, a raw material
comprising an aliphatic compound produced by algae, together with a
hydrocarbon solvent in which critical temperature is 90°C or higher (or
a mixed fluid comprising the hydrocarbon solvent) from the line L2, is
10 continuously fed from the line LI to the aliphatic compound extraction
and separation vessel 1, and this mixture is allowed to remain in the
aliphatic compound extraction and separation vessel 1 for a fixed time.
At this time, temperature and pressure are adjusted at a temperature
equal to or higher than the critical temperature of the hydrocarbon
15 solvent so that the solubility of the aliphatic compound in 100 g of the
hydrocarbon solvent is 15 g or less, and the mixture is held in the
aliphatic compound extraction and separation vessel 1. Examples of a
method for adjusting temperature and pressure include a method of
adjusting the temperature and pressure of the hydrocarbon solvent (or
20 the mixed fluid comprising the hydrocarbon solvent) transferred from
the solvent separation vessel 2 by the pressure/flow rate adjustment
apparatus 14, a method of adjusting the temperature and pressure of the
hydrocarbon solvent introduced as a makeup gas from the line L2, a
method of adjusting pressure by a pressure adjustment valve VI, and a
25 method of adjusting the temperature of the mixture by the temperature
adjustment apparatus 13. One of the above methods may be used
24
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alone, or two or more of the above methods may be used in
combination.
[0073] Next, in the aliphatic compound extraction and separation vessel
1, a mixture of the soluble portion of the aliphatic compound in the
5 hydrocarbon solvent and the hydrocarbon solvent, and the insoluble
portion (residue) of the aliphatic compound in the hydrocarbon solvent
are separated by gravity sedimentation. The above mixture of the
soluble portion and the hydrocarbon solvent is transferred to the solvent
separation vessel 2 through the line L4 coupled to the top of the
10 aliphatic compound extraction and separation vessel 1.
[0074] A line L5 having a valve V3 is coupled to the bottom of the
aliphatic compound extraction and separation vessel 1, and the other
end of the line L5 is led to a recovery container 15. The above
insoluble portion separated in the aliphatic compound extraction and
15 separation vessel 1 is transferred to the recovery container 15 through
the line L5. When the above insoluble portion is recovered, a small
amount of the hydrocarbon solvent can be recovered together, and the
hydrocarbon solvent may be recovered from the recovery container 15
and reused.
20 [0075] The mixture of the soluble portion of the aliphatic compound in
the hydrocarbon solvent and the hydrocarbon solvent is further
separated into the aliphatic compound (purified aliphatic compound)
and the hydrocarbon solvent by gravity sedimentation in the solvent
separation vessel 2. This separation operation is an operation in which
25 temperature and/or pressure are adjusted at a temperature equal to or
higher than the critical temperature of the hydrocarbon solvent so that
25
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#
the solubility of the aliphatic compound in the hydrocarbon solvent is
substantially zero. This separation operation is a gravity sedimentation
operation involving no phase change, and therefore, the latent heat of
vaporization is unnecessary, and sensible heat recovery is possible, and
5 therefore, this separation operation is useful in terms of energy saving.
Examples of a method for decreasing solubility include a method of
setting pressure in the solvent separation vessel 2 lower than the
pressure of the aliphatic compound extraction and separation vessel 1 by
the adjustment of the valve V2, and a method of providing a heating
10 apparatus in the line L4 and setting temperature in the solvent
separation vessel 2 higher than temperature in the aliphatic compound
extraction and separation vessel 1. It is possible to set the pressure of
the solvent separation vessel 2 somewhat lower and set temperature in
the solvent separation vessel 2 somewhat higher. Examples of the
15 heating apparatus provided in the line L4 may include a heat exchanger.
In this case, it is possible to lead the line L2 to the heat exchanger and
use the hydrocarbon solvent from the solvent separation vessel 2 as a
heat source.
[0076] The line L6 having a valve V4 is coupled to the bottom of the
20 solvent separation vessel 2, and the other end of the line L6 is led to a
recovery container 16. The purified aliphatic compound separated in
the solvent separation vessel 2 is transferred to the recovery container
16 through the line L6 coupled to the bottom of the solvent separation
vessel 2. The purified aliphatic compound can be recovered together
25 with a small amount of the hydrocarbon solvent, and the hydrocarbon
solvent may be recovered from the recovery container 16 and reused.
26
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On the other hand, the separated hydrocarbon solvent is transferred to
the line LI through the line L2 coupled to the top of the solvent
separation vessel 2.
[0077] The purified aliphatic compound is transferred from the
5 recovery container 16 to the hydrotreatment reactor 3 through the line
L7. A valve V5, a hydrogen introduction line L8, and a heating
apparatus 17 are provided in the line L7 from the upstream side, and the
other end of the line L7 is led to the top of the hydrotreatment reactor 3.
Thus, it is possible to mix the purified aliphatic compound with
10 hydrogen from the line L8, heat the mixture to a predetermined
temperature by the heating apparatus 17, and then feed the mixture to
the hydrotreatment reactor 3 to perform hydrotreatment with a catalyst.
[0078] In addition, a branch line L9 is provided in the line L7. One
end of the branch line L9 is coupled to the upstream side of the valve
15 V5 in the line L7, and the other end is coupled between the valve V5 in
the line L7 and the coupling portion of the hydrogen introduction line
L8. Further, a valve V6 and an intermediate tank 18 are provided in
the branch line L9 in this order from the upstream side. When the
apparatus is operated with the valve V5 opened and the valve V6 closed,
20 the purified aliphatic compound is continuously fed to the
hydrotreatment reactor 3 through the line L6. On the other hand, when
the apparatus is operated with the valve V5 closed and the valve V6
opened, the purified aliphatic compound, which is a raw material in
hydrotreatment, can accumulate temporarily in the intermediate tank 20,
25 and the feed of the purified aliphatic compound to a hydrotreatment step
can be stabilized.
27
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[0079] A line L10 is coupled to the bottom of the hydrotreatment
reactor 3, and a hydrocarbon fuel produced by hydrotreatment is
recovered from the line L10.
[0080] The present invention is not limited to the above embodiment.
5 For example, in the above embodiment, an example in which the first
step and the second step are continuously performed using the
production apparatus shown in Figure 1 has been described, but these
steps need not be continuously performed.
[0081] In addition, the lines L6 and L7 may be directly connected to
10 each other without providing the recovery container 16.
[0082] In addition, the hydrotreatment reactor 3 may be at a location
different from that of the aliphatic compound extraction and separation
vessel 1 and the solvent separation vessel 2, and a transport step may be
provided between the first step and the second step. In this case, the
15 intermediate tank 18 can be used as a raw material (reception) tank.
Examples
[0083] The present invention will be more specifically described below
based on Examples, but the present invention is not limited to the
20 following Examples in any way.
[0084] (Culture)
The culture of Euglena was carried out according to a method
described in an appendix to the book "Yugurena Seiri To Seikagaku
(Euglena Physiology and Biochemistry)," Gakkai Shuppan Senta
25 (Academic Society Publication Center) (1989). Using an E. Gracilis Z
strain and using a pool having an area of 1.2 m , culture was performed
28
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?
outdoors by sunlight in a Cramer-Myers medium for 7 days. Then,
according to description on page 114 of the book, anaerobic treatment
was performed for a whole day, and further, this was dried at 150°C to
obtain a dry powder of Euglena. The same operation was repeated to
5 recover 1700 g of a Euglena dry powder subjected to anaerobic
treatment.
[0085] (Solvent Extraction)
Extraction was performed using, as a solvent, hexane, which
was most widely used for the extraction of aliphatic compounds from
10 algae. A flask having a volume of 20 L was charged with 1650 g of
the above dry powder and 10 L of hexane, and an obtained suspension
was heated and stirred under atmospheric pressure at 55°C for 1 hour
and then filtered to recover a hexane solution.
Hexane was distilled off from this hexane solution using an
15 evaporator (water bath temperature 50°C) to obtain an extract from alga
bodies in the proportion of 27.5% by mass based on dry alga bodies.
This extract was analyzed by a GC-MS method and an NMR method,
and it was confirmed that this extract was a wax ester comprising
myristyl myristate as a main component. In addition, the content of
20 oxygen atoms contained in this extract was 8.1 % by mass.
As a result of separately measuring the solubility of this extract
in hexane at 55°C, it was 42 g per 100 g of hexane. In other words, the
above solvent extraction was carried out with this solubility. This
extract is hereinafter referred to as a hexane-extracted oil.
25 [0086] (Measurement of Solubility in Propane and Propane Extraction)
The measurement of the solubility of the above
29
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Cr
hexane-extracted oil in propane and the extraction of the above
hexane-extracted oil with propane were carried out under each condition
using a pressure container having an internal volume of 1 L.
In the above measurement and extraction, the container
5 controlled to a predetermined temperature was charged with the
hexane-extracted oil, propane was fed thereto, and pressure was held in
the state of 6 MPa for 1 h to dissolve the hexane-extracted oil in the
propane (propane extraction). Then, the total amount of the propane in
a state in which part of the hexane-extracted oil was dissolved was
10 drawn from the container. At each temperature, the hexane-extracted
oil remained in the pressure container after the propane was drawn, and
therefore, it was determined that the one drawn from the pressure
container was the propane in which the hexane-extracted oil at
saturation concentration was dissolved, at each temperature.
15 The propane was volatilized from this propane in which the
hexane-extracted oil at saturation concentration was dissolved, the
dissolved hexane-extracted oil was recovered and weighed, and the
solubility of the hexane-extracted oil at the temperature was calculated
as mass based on 100 g of propane.
20 In addition, at each temperature, propane was newly added to
the hexane-extracted oil that was insoluble in the propane in the above
propane extraction and remained in the pressure container after propane
discharge, and the propane extraction of the hexane-extracted oil and the
recovery of a propane-soluble portion were performed as in the above.
25 Then, this operation was repeatedly carried out until the proportion of
the mass of the total of the hexane-extracted oil recovered by propane
30
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extraction to the mass of the hexane-extracted oil charged into the
pressure container (recovery rate) reached 90% or more.
The measurement result of the solubility of the hexane-extracted
oil in propane at each temperature is shown in Table 2. From the
5 results shown in Table 2, it is seen that the solubility changes largely
between temperatures of 110°C and 120°C.
[0087]
[Table 2]
Temperature
(°C)
40
70
90
100
110
111
112
114
116
118
120
122
Solubility
(g/lOOg)
43.0
42.0
41.2
33.1
26.2
13.7
8.0
5.5
4.0
2.5
2.0
0.8
10 [0088] (Preparation of Hydrodeoxygenation Catalyst)
18.0 g of water glass No. 3 was added to 3000 g of a sodium
aluminate aqueous solution having a concentration of 5% by mass, and
the aqueous solution was placed in a container kept at 65°C. On the
other hand, a solution in which 6.0 g of phosphoric acid (concentration
15 85%) was added to 3000 g of an aluminum sulfate aqueous solution
31
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having a concentration of 2.5% by mass was prepared in another
container kept at 65 °C, and the above-described aqueous solution
comprising sodium aluminate was dropped into this. The dropping
was completed with a point of time when the pH of the mixed solution
5 reached 7.0 taken as an end point, and an obtained slurry-like product
was filtered through a filter to obtain a cake-like slurry.
This cake-like slurry was transferred to a container to which a
reflux condenser was attached, 150 ml of distilled water and 10 g of a
27% ammonia aqueous solution were added, and the slurry was heated
10 and stirred at 75°C for 20 hours. The slurry was placed in a kneading
apparatus, and kneaded while being heated to 80°C or higher to remove
moisture, to obtain a clay-like kneaded material. The obtained
kneaded material was extruded into a cylindrical shape having a
diameter of about 1.5 mm by an extrusion molding machine, cut to a
15 length of about 3 mm, dried at 110°C for 1 hour, and then fired at 550°C
to obtain a molded support.
50 g of the obtained molded support was placed in an eggplant
type flask, and an impregnation aqueous solution comprising 17.3 g of
molybdenum trioxide, 13.2 g of nickel(II) nitrate hexahydrate, 3.9 g of
20 phosphoric acid (concentration 85%), and 4.0 g of malic acid was
injected into the flask while degassing was performed by a rotary
evaporator, to perform impregnation. The impregnated sample was
dried at 120°C for 1 hour and then fired at 550°C to obtain a catalyst.
The physical properties of the catalyst are shown in Table 3.
25 [0089]
[Table 3]
32
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t
Catalyst
composition
(% by mass)
Support mass basis
Support mass basis
Pore volume (ml/g)
AI2O3
Si02
P2O5
M0O3
NiO
Average pore diameter (nm)
91.2
4.8
4.0
24.0
2.6
0.75
7.0
[0090] [Comparative Example 1]
A reaction tube filled with the above catalyst (10 ml) was
attached to a fixed-bed flow type reaction apparatus in a countercurrent
5 manner. Then, the presulfurization of the catalyst was performed for 4
hours under the conditions of a catalyst layer average temperature of
300°C, a hydrogen partial pressure of 6 MPa, a liquid space velocity of
1 h"1, and a hydrogen/oil ratio of 200 NL/L ("NL" is the volume of a
hydrogen gas at 0°C and atmospheric pressure), using a straight-run
10 light oil to which dimethyl disulfide was added (sulfur 3% by mass).
After the presulfurization, hydrodeoxygenation treatment was
performed using the above-described hexane-extracted oil (propane
extraction was not performed) as a raw material oil. At this time,
dimethyl sulfide was added to the raw material oil so that sulfur content
15 (in terms of sulfur atoms) with respect to the raw material oil was 10
ppm by mass. For the conditions of the treatment, hydrogen pressure
was set to 6.0 MPa, liquid space velocity was set to 1.0 h"1, and
hydrogen/oil ratio was set to 510 NL/L. In addition, treatment
temperature was adjusted so that the content of oxygen atoms in a
20 produced oil was 0.5% by mass or less, which was necessary to ensure
33
FP11-0670-00
fuel oil quality, and the treatment temperature was set to 280°C at the
time of the start of the treatment based on the results of preliminary
study. Then, the deterioration of the catalyst (activity decrease) was
significant, and therefore, the treatment temperature had to be largely
5 increased over time in order to maintain the above content of oxygen
atoms in a produced oil. When the deterioration rate of the catalyst
was expressed using an increase in reaction temperature per day
necessary to maintain the content of oxygen atoms in the produced oil at
0.5% by mass or less, as an indicator (referred to as a "catalyst
10 deterioration rate indicator"), it was 11.2°C/day.
[0091] (Comparative Example 2)
Hydrodeoxygenation treatment was performed by an operation
similar to that of Comparative Example 1 except that instead of the
hexane-extracted oil in Comparative Example 1, a propane-soluble
15 portion was used that was obtained by repeating propane extraction
under the condition (temperature 110°C) in which the solubility of the
hexane-extracted oil in propane under a pressure of 6 MPa was 26.2 g
per 100 g of propane, shown in the above-described Table 1, until the
recovery rate reached 90% or more. The deterioration of the catalyst
20 was significant as in Comparative Example 1, and the catalyst
deterioration rate indicator was 10.4°C/day.
[0092] (Example 1)
Hydrodeoxygenation treatment was performed by an operation
similar to that of Comparative Example 1 except that instead of the
25 hexane-extracted oil in Comparative Example 1, a propane-soluble
portion was used that was obtained by repeating propane extraction
34
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*
under the condition (temperature 111°C) in which the solubility of the
hexane-extracted oil in propane under a pressure of 6 MPa was 13.7 g
per 100 g of propane, shown in the above-described Table 1, until the
recovery rate reached 90% or more. Catalyst deterioration was
5 reduced compared with Comparative Example 1 and Comparative
Example 2, and the catalyst deterioration rate indicator was 0.7°C/day.
[0093] (Example 2)
An operation similar to that of Comparative Example 1 was
performed except that instead of the hexane-extracted oil in
10 Comparative Example 1, a propane-soluble portion was used that was
obtained by repeating propane extraction under the condition
(temperature 112°C) in which the solubility of the hexane-extracted oil
in propane under a pressure of 6 MPa was 8.0 g per 100 g of propane,
shown in the above-described Table 1, until the recovery rate reached
15 90% or more. Catalyst deterioration was further reduced, and the
catalyst deterioration rate indicator was 0.5°C/day.
[0094] (Example 3)
Hydrodeoxygenation treatment was performed by an operation
similar to that of Comparative Example 1 except that instead of the
20 hexane-extracted oil in Comparative Example 1, a propane-soluble
portion was used that was obtained by repeating propane extraction
under the condition (temperature 114°C) in which the solubility of the
hexane-extracted oil in propane under a pressure of 6 MPa was 5.5 g per
100 g of propane, shown in the above-described Table 1, until the
25 recovery rate reached 90% or more. Catalyst deterioration was further
reduced, and the catalyst deterioration rate indicator was 0.3°C/day.
35
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[0095] The results of the Comparative Examples and the Examples
described above are collectively shown in Table 4. In addition,
impurity concentration in the hexane-extracted oil and the
propane-soluble portions obtained by performing propane extraction
5 under the respective conditions, subjected to hydrodeoxygenation
treatment, is shown together in Table 4. From the results shown in
Table 4, it is seen that according to the method of the present invention,
the catalyst deterioration rate indicator is significantly improved, and a
high quality fuel can be commercially stably produced from an aliphatic
10 compound produced by algae.
[0096]
[Table 4]
Comparative
Example 1
Comparative
Example 2
Example 1
Example 2
Example 3
Solubility
(g/lOOg)
...
26.2
13.7
8.0
5.5
Impurity concentration (ppm by mass)
Mg
270
12
3
1
<1
Na
920
26
4
3
2
K
250
11
3
3
<3
Ca
170
7
2
1
<1
Al
3
<1
<1
<1
<1
Zn
45
2
1
<1
<1
Fe
110
7
2
1
1
P
3800
120
9
5
<3
Catalyst
deterioration
rate indicator
(°C/day)
11.2
10.4
0.7
0.5
0.3
Industrial Applicability
15 [0097] According to the present invention, a high quality hydrocarbon
fuel can be commercially stably produced from an aliphatic compound
produced by algae. Therefore, the present invention is very useful in
producing hydrocarbon fuels from biomass raw materials.
36
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Reference Signs List
[0098] 1 ... aliphatic compound extraction and separation vessel, 2 ...
solvent separation vessel, 3 ... hydrotreatment reactor, 11 ... pump, 12 ...
mixing apparatus, 13, 17 ... heating apparatus, 14 ... pressure/flow rate
adjustment apparatus, 15, 16 ... recovery container, 18 ... intermediate
tank, LI to L10 ... line, VI to V5 ... valve.
37

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CLAIMS
[Claim 1]
A method for producing a hydrocarbon fuel, comprising:
5 a first step of holding a mixture containing an aliphatic
compound produced by an alga, and a hydrocarbon solvent having a
critical temperature of 90°C or higher in a supercritical state, with
temperature and pressure adjusted so that a solubility of the aliphatic
compound in 100 g of the hydrocarbon solvent is 15 g or less, and then
10 recovering a soluble portion of the aliphatic compound in the
hydrocarbon solvent; and
a second step of subjecting the soluble portion recovered in the
first step to hydrotreatment using a catalyst.