DESCRIPTION
Title of Invention: METHOD FOR PRODUCING FUEL OIL
BASE
Technical Field
5 [0001] The present invention relates to a method for producing a fuel
oil base.
Background Art
[0002] In recent years, global warming issues have been coming to the
fore, and suppression of the emission of carbon dioxide gas which is
10 one of greenhouse gases and a reduction in the concentration of carbon
dioxide in the air by fixing carbon dioxide are big problems. Under
such a circumstance, use of fossil fuels containing fixed carbon dioxide
as energy leads to discharging the fixed carbon dioxide to the air again,
causing environmental problems. The fossil fuel is a limited resource,
15 leading to a problem of exhaustion.
[0003] To solve such problems, fuel resources other than the fossil fuels
are needed, and development of biofuels using higher plants and algae
as a raw material has been increasingly expected.
[0004] As the candidate higher plants for the biofuel raw material,
20 soybean, corn, palm, and the like are known; in the case where such
edible crops are used as a raw material, a scarcity of food is concerned.
Although production of the biofuels from inedible plants such as
Jatropha Curcas and Camelina sativa has been advanced, these inedible
plants have a problem of a small amount of fuel production per unit
25 area.
[0005] In contrast, photosynthetic microorganisms and protozoa living
widely in ponds and marshes have the same photosynthetic ability as the
plants, and these photosynthetic microorganisms and protozoa
biosynthesize carbohydrate and lipid from water and carbon dioxide,
and accumulate a few tens % by mass of these inside the cells. The
5 production amount thereof is higher than that of the higher plants; for
example, it is known that the photosynthetic microorganisms and
protozoa achieve the production amount per unit area 10 times or more
that of the palm.
[0006] A microalga Euglena, which is one of the photosynthetic
10 micro-o.r-ga nisms, belongs to flagellates, and includes Euglena gracilis
famous as a mobile alga.
[0007] Euglena is a genus classified both in zoology and in botany.
In zoology, Euglena is classified into the order: Euglenida which
belongs to the plant flagellate subclass: Phytomastigophorea, the
15 flagellate class: Mastigophorea, the phylum: Protozoa; and Euglenida
comprises three suborders, Euglenoidina, Peranemoidina, and
Petalomonadoidina. Euglenoidina includes Euglena, Trachelemonas,
Strombonas, Phacus, Lepocinelis, Astasia, and Colacium as genuses.
In botany, Euglena is classified into the order: Euglenales, the class:
20 Euglenophyceae, the division: Euglenophyta; and Euglenales includes
Euglena and the same genuses as those in the classification in zoology.
[0008] Euglena accumulates paramylon as a carbohydrate inside the
cells. Paramylon is a polymer particle produced by polymerization of
approximately 700 glucose molecules through P-1,3-bond.
25 [0009] Patent Literature 1 discloses a method for producing a wax ester
utilizing conversion of stored polysaccharide paramylon to a wax ester
by a fermentation phenomenon when Euglena is kept under an
anaerobic condition.
Citation List
Patent Literature
5 [0010] Patent Literature 1: Japanese Examined Patent Publication No.
3-65948
Summary of Invention
Technical Problem
[0011] The main components of vegetable oils and fats derived fiom
10 typical algae are oils and fats having a main skeleton having 16 or more
carbon atoms, and such a number of carbon atoms corresponds to that of
gas oil or petroleum fractions heavier than gas oil. The wax ester
produced by the anaerobic fermentation of Euglena comprises fatty acid
and alcohol having 14 carbon atoms mainly. For this reason, a fuel oil
15 base for an aviation fuel, whose number of carbon atoms is in the range
of 10 to 16, can be easily produced from the wax ester derived fiom
Euglena.
[0012] In the anaerobic fermentation of Euglena, diglyceride and
triglyceride are produced in addition to the wax ester; these oils and fats
20 are oils and fats having 16 or more carbon atoms, leading to a problem
of difficulties in application in production of a fuel oil base for an
aviation fuel.
[0013] An object of the present invention is to provide a method for
producing a fuel oil base that can produce a wax ester from a microalga
25 Euglena with high efficiency to produce a fuel oil base suitable for an
aviation fuel efficiently. Another object of the present invention is to
provide a fuel oil base produced by the above production method, a he1
oil composition including the fuel oil base, and a method for producing
the fuel oil composition.
Solution to Problem
5 [0014] A fxst aspect according to the present invention relates to a
method for producing a he1 oil base, comprising a first step of
aerobically culturing a microalga Euglena under a nitrogen-deficient
condition; a second step of adding a nutrient to a treatment solution
containing the microalga Euglena cultured in the fxst step, adjusting a
10 dissolved oxygen concentration of the treatment solution to 0.03 mgL
or less, and performing anaerobic fermentation of the microalga
Euglena to produce a wax ester; and a third step of hydrotreating a raw
material oil containing the wax ester to produce a fuel oil base.
[0015] In the production method, an amount of paramylon accumulated
15 in the microalga Euglena can be increased by aerobically culturing the
microalga Euglena under a nitrogen-deficient condition in the first step.
[0016] However, according to the knowledge of the present inventors,
when the microalga Euglena cultured in the first step is used, the
amount of accumulated paramylon which is the raw material for the
20 wax ester is increased, but the eEciency of the wax ester production in
the anaerobic fermentation is reduced so that the proportion of the wax
ester to diglyceride and triglyceride remains a low level. As described
above, because diglyceride and triglyceride both have 16 or more
carbon atoms, these are difficult to use in production of the fuel oil base
25 for an aviation fuel.
[0017] To solve the problem, in the second step in the production
method, a nutrient is added to the treatment solution containing the
microalga Euglena cultured in the first step. The nutrient is added to
the treatment solution before the dissolved oxygen concentration of the
treatment solution is adjusted to 0.03 mg/L or less for the anaerobic
5 fermentation; thereby, the efficiency of the wax ester production in the
anaerobic fermentation of the microalga Euglena can be significantly
improved.
[0018] Namely, in the production method, the amount of paramylon
accumulated in the microalga Euglena can be increased in the first step,
10 and the problem caused in the first step can be eliminated in the second
step to improve the efficiency of the wax ester production in the
anaerobic fermentation, thereby producing the wax ester efficiently.
The wax ester produced through the first step and the second step
comprises fatty acid and alcohol having 14 carbon atoms mainly as
15 described above; for this reason, a fuel oil base suitable for an aviation
fuel can be easily produced fiom the wax ester with high efficiency.
[0019] It is thought that the effect of the second step is attained for the
following reason. First, because the enzyme related to the anaerobic
fermentation is protein, a nutrient for biosynthesizing amino acid that
20 forms protein is needed. It is thought that because the first step is
performed under a nitrogen-deficient condition, a new nutrient
(particularly a nitrogen source) is difficult to feed to the microalga
Euglena fiom the outside; as a result, the amount of the enzyme related
to the generation of the wax ester produced in the microalga Euglena is
25 reduced, reducing the efficiency of the wax ester production. It is
thought that the production of the enzyme is promoted by adding the
nutrient in the second step to improve the efficiency of the wax ester
production.
[0020] The second step may be a step of adjusting the dissolved oxygen
concentration of the treatment solution to 0.03 mgL or less within 3
5 hours after the nutrient is added to the treatment solution.
[0021] If the nutrient is added 3 hours before the dissolved oxygen
concentration of the treatment solution is adjusted to 0.03 mg/L or less,
the nutrient can be prevented fiom being consumed before the anaerobic
fermentation, and the amount of the enzyme produced which is related
10 to the generation of the wax ester can be more securely increased to
improve the efficiency of the wax ester production more significantly.
[0022] It is preferable that the nutrient contain a nitrogen source. By
adding the nutrient containing a nitrogen source, the amount of the
enzyme produced which is related to the generation of the wax ester can
15 be increased more securely to improve the efficiency of the wax ester
production more significantly.
[0023] It is preferable that the nitrogen source contain an ammonium
compound. By adding the nutrient containing such a nitrogen source,
the amount of the enzyme produced which is related to the generation of
20 the wax ester can be increased more securely to improve the efficiency
of the wax ester production more significantly. The ammonium
compound is advantageous in availability and cost.
[0024] The nutrient may contain a carbon source. The nutrient may
contain a nitrogen source and a carbon source.
25 [0025] It is preferable that the carbon source contain glucose. The
nutrient containing glucose as the carbon source has a high effect of
improving the efficiency of the wax ester production, and is
advantageous in availability and cost.
[0026] The third step may be a step including a hydrorefining treatment
and a hydroisomerization treatment as thehydrotreatment. By
5 performing the hydrorefining treatment and the hydroisomerization
treatment, the proportion of isoparaffin contained in the fuel oil base can
be increased to improve low temperature performance.
[0027] A second aspect according to the present invention relates to a
fuel oil base produced by the production method.
10 [0028] A third aspect according to the present invention relates to a
method for producing a fuel oil composition, comprising a step of
producing a he1 oil composition having a sulfur content of 10 mass
ppm or less and a freezing point of -47°C or less using the fuel oil base
produced by the production method.
15 [0029] The content of the fuel oil base in the fuel oil composition can
be 1 to 50% by volume.
[0030] The fuel oil composition may contain at least one additive
selected from an antioxidant, an antistatic agent, a metal deactivator,
and a deicing agent.
20 [0031] A fourth aspect according to the present invention relates to a
fuel oil composition produced by the production method. It is
preferable that the fuel oil composition satisfy specification values for
an aviation turbine fuel oil specified in ASTM D7566-11.
Advantageous Effects of Invention
25 [0032] According to the present invention, a method for producing a
fuel oil base that can produce a wax ester from a microalga Euglena
with high efficiency to produce a fuel oil base suitable for an aviation
fuel efficiently is provided. According to the present invention, a fuel
oil base produced by the production method, a fuel oil composition
containing the fuel oil base, and the method for producing the fuel oil
5 composition are also provided.
Brief Description of Drawings
[0033] [Figure 11 Figure 1 is a graph showing the results of component
analysis of oils and fats in Example 1.
[Figure 21 Figure 2 is a graph showing the results of component analysis
10 of oils and fats in Examples 1 to 3 and Comparative Examples 1 and 2.
Description of Embodiments
[0034] Suitable embodiments according to the present invention will be
described below.
[0035] The method for producing a fuel oil base according to the
15 present embodiment comprises a first step of aerobically culturing a
microalga Euglena under a nitrogen-deficient condition; a second step
of adding a nutrient to a treatment solution containing the microalga
Euglena cultured in the first step, adjusting the dissolved oxygen
concentration of the treatment solution to 0.03 mg/L or less, and
20 performing anaerobic fermentation of the microalga Euglena to produce
a wax ester; and a third step of hydrotreating a raw material oil
containing the wax ester to produce a fuel oil base.
[0036] The microalga Euglena refers to those included in the genus:
Euglena, the order: Euglenida which belongs to the plant flagellate
25 subclass: Phytomastigophorea, the flagellate class: Mastigophorea, the
phylum: Protozoa in zoology. The microalga Euglena may refer to
those included in the genus: Euglena, the order: Euglenales, the class:
Euglenophyceae, the division: Euglenophyta in botany.
[0037] In the present embodiment, a microalga Euglena aerobically
cultured under an autotrophic culturing condition with carbon dioxide
5 flows can be used in the first step. In other words, the production
method may comprise a pre-culturing step of aerobically culturing the
microalga Euglena under the autotrophic culturing condition with
carbon dioxide flows, prior to the first step.
[0038] Hereinafter, the pre-culturing step and the first to third steps will
10 be described in detail.
[0039] (Pre-culturing step)
The pre-culturing step is a step of aerobically culturing the
microalga Euglena under an autotrophic culturing condition with carbon
dioxide flows.
15 [0040] In the method described in Patent Literature 1, an organic
substance such as glucose is added as a carbon source to perform
aerobic culturing; however, such a method has little merit in cost and
cannot attain fixation of carbon dioxide.
[0041] In the pre-culturing step, carbon dioxide is used as the carbon
20 source; for this reason, the method according to the present embodiment
has great merits in cost and can attain a reduction in the environmental
load by fixation of carbon dioxide. Usually, the productivity when
carbon dioxide is used as the carbon source tends to be inferior to that
when glucose or the like is used as the carbon source; however, the
25 production method according to the present embodiment can produce
the wax ester with high efficiency through the first step and the second
step; for this reason, sufficient productivity is achieved even if the
pre-culturing step is used.
[0042] Examples of culturing under an autotrophic culturing condition
include culturing in an autotrophic culture medium. As the autotrophic
5 culture medium, an AY culture medium can be suitably used.
[0043] The AY culture medium is an autotrophic culture medium
composed by removing heterotrophic components such as glucose,
malic acid, and amino acid fiom a Koren-Hutner culture medium
usually used as the heterotrophic culture medium for the microalga
10 Euglena.
[0044] Examples of the AY culture medium includes an AY culture
medium having the composition shown in Table 1. In Table 1, VBI
designates vitamin B1, and VB2 designates vitamin B2.
[0045] [Table 11
[ Component I & I Component 1 mglL
15
[0046] It is preferable that the autotrophic culture medium be adjusted
to an acidic condition, for example, it is preferable that the pH be
adjusted to 2.5 to 6.5, and it is more preferable that the pH be adjusted
to 3.0 to 6.0. The pH can be adjusted using dilute sulfuric acid, for
20 example. It is preferable that the autotrophic culture medium be
subjected to a sterilizing treatment such as autoclave sterilization.
[0047] The pre-culturing step can be performed by planting the cell
strains of the microalga Euglena (such as Euglena gracilis Z strains) in
the autotrophic culture medium and aerating the autotrophic culture
medium with carbon dioxide, for example. More specifically, the
5 pre-culturing step can be performed by flowing carbon dioxide in a
concentration of 5 to 20% at a flow rate of 0.05 to 0.2 wm (100 to 400
mllmin), for example. "vvm" is an abbreviation of "volume per
volume per minute" representing a gas flow amount per unit volume.
[0048] In the pre-culturing step, the autotrophic culture medium may be
10 irradiated with light; as the condition of irradiation with light, a light
and dark cycle in which light is turned on for 12 hours and then turned
off for 12 hours can be used to make the irradiation condition close to
the outdoor condition of day and night, for example. The intensity of
light to be irradiated can be 600 to 1200 pmo~(m2.si)n terms of the
15 intensity of the light emitted onto the top surface of the autotrophic
culture medium.
[0049] The culturing time in pre-culturing step may be 24 to 120 hours,
and preferably 48 to 96 hours, for example.
[0050] It is preferable that the culturing temperature in the pre-culturing
20 step be 26 to 32'C, and it is more preferable that the temperature be 28
to 30°C.
[0051] A specific aspect of the pre-culturing step will be shown below.
[0052] In this aspect, first, the AY culture medium having the
composition shown in Table 1 is prepared using deionized water, the pH
25 is adjusted to 3.5 with dilute sulfuric acid, and autoclave sterilization is
performed. Next, approximately 2 L of the sterilized AY culture
medium is poured to a level of 20 cm in an acrylic culturing container
measuring a length of 10 cm, a width of 10 cm, and a height of 27 cm,
and Euglena gracilis Z strains are planted in the medium.
[0053] Next, the culturing container is placed inside of a thermostat
5 water bath installed on a magnetic stirrer SRSBlOLA (made by
ADVANTEC Co., LTD.), and the medium is stirred at a strength of 300
rpm using a 6 cm stirrer. A metal halide lamp Eye Clean Ace BT
(made by Iwasaki Electric Co., Ltd.) as a light source is placed
immediately above the surface of the culture solution, and its height is
10 adjusted such that the light illuminating the surface of the culture
solution has an intensity of approximately 900 pmo~(m2~s).
[0054] For the light irradiation time, the light and dark cycle in which
light is turned on for 12 hours and then turned off for 12 hours is
employed to make the condition close to the outdoor condition of day
15 and night; carbon dioxide in a concentration of 15% as the carbon
source is flowed at a flow rate of 0.1 wm (200 mL/min), and culturing
is performed.
[0055] After culturing for 3 days, Euglena is centrihged from the 2 L
culture solution (2500 rpm, 5 minutes, room temperature), and was
20 washed with deionized water once to obtain the microalga Euglena
subjected to the pre-culturing step.
[0056] (First step)
The first step is a step of aerobically culturing the microalga
Euglena under a nitrogen-deficient condition. The first step can
25 increase the amount of paramylon accumulated in the microalga
Euglena.
[0057] The microalga Euglena used in the f ~ s tst ep may be the
microalga Euglena cultured in the pre-culturing step, for example.
[0058] Examples of culturing under a nitrogen-deficient condition
include culturing in a nitrogen-deficient culture medium. Here the
nitrogen-deficient culture medium refers to a culture medium containing
a nitrogen-containing compound in an amount of 5 mgL or less. For
the nitrogen-deficient culture medium, a nitrogen-deficient AY culture
medium or the like can be suitably used.
[0059] Examples of the nitrogen-deficient culture medium include a
nitrogen-deficient AY culture medium having a composition shown in
Table 2.
[0060] [Table 21
[0061] It is preferable that the nitrogen-deficient culture medium be
adjusted to an acidic condition, for example, it is preferable that the pH
be adjusted to 2.5 to 6.5, and it is more preferable that the pH be
adjusted to 3.0 to 6.0. The pH can be adjusted with dilute sulfuric
acid, for example. It is preferable that the nitrogen-deficient culture
medium be subjected to a sterilizing treatment such as autoclave
sterilization.
[0062] The nitrogen-deficient culture medium may be irradiated with
light in the first step; as the condition of irradiation with light, for
example, a light and dark cycle in which light is turned on for 12 hours
and then turned off for 12 hours can be used to make the irradiation
condition close to the outdoor condition of day and night. The
5 intensity of the light to be irradiated can be 600 to 1200 pmo~(m2~isn)
terms of the intensity of the light emitted on the top surface of the
nitrogen-deficient culture medium.
[0063] In the first step, the nitrogen-deficient culture medium may be
aerated with carbon dioxide; for example, carbon dioxide in a
10 concentration of 5 to 20% may be flowed at a flow rate of 0.05 to 0.2
wm (100 to 400 mL/min).
[0064] It is preferable that the proportion of the microalga Euglena
contained in the nitrogen-deficient culture medium be 0.05 to 5.0 g/L,
and it is more preferable that the proportion be 0.2 to 1.0 g/L.
15 [0065] It is preferable that the culturing temperature in the first step be
26 to 32OC, and it is more preferable that the temperature be 28 to 30°C.
[0066] It is preferable that the culturing time in the frst step be 24 to 72
hours, and it is more preferable that the time be 24 to 48 hours. At a
culturing time of 24 hours or more, the amount of paramylon
20 accumulated can be more significantly increased; at a culturing time of
72 hours or less, an increase in the time necessary for the first step can
be suppressed.
[0067] A specific aspect of the first step will be shown below.
[0068] In this aspect, first, the nitrogen-deficient AY culture medium
25 having the composition shown in Table 2 is prepared using deionized
water, the pH is adjusted to 3.5 with dilute sulfuric acid, and autoclave
sterilization is performed. Next, approximately 4.5 L of the sterilized
nitrogen-deficient AY culture medium is poured to a level of 20 cm in
an acrylic culturing container measuring a length of 15 cm, a width of
15 cm, and a height of 27 cm, and the microalga Euglena cultured in the
5 pre-culturing step is planted in the medium. The initial concentration
of the microalga Euglena in the nitrogen-deficient AY culture medium is
0.3 gL.
[0069] Next, the culturing container is placed inside of a thermostat
water bath installed on a magnetic stirrer SRSBlOLA (made by
10 ADVANTEC Co., LTD.), and the medium is stirred at a strength of 300
rpm using a 6 cm stirrer. A metal halide lamp Eye Clean Ace BT
(made by Iwasaki Electric Co., Ltd.) is placed immediately above the
surface of the culture solution, and its height is adjusted such that the
light illuminating the surface of the culture solution has an intensity of
15 approximately 900 pmol/(m2.s).
[0070] For the light irradiation time, the light and dark cycle in which
light is turned on for 12 hours and then turned off for 12 hours is
employed to make the condition close to the outdoor condition of day
and night; carbon dioxide in a concentration of 15% as the carbon
20 source is flowed at a flow rate of 0.1 vvm (200 mL/min), and culturing
is performed.
[0071] After culturing for 48 hours, the culture solution may be fed to
the second step as it is, or may be condensed with a centrifuge or the
like and be fed to the second step. Here, for example, the 2 L culture
25 solution can be condensed to approximately 0.5 L.
[0072] (Second step)
The second step is a step of adding a nutrient to the treatment
solution containing the microalga Euglena cultured in the frst step,
adjusting the dissolved oxygen concentration of the treatment solution
to 0.03 mg/L or less, and performing the anaerobic fermentation of the
5 microalga Euglena to produce a wax ester.
[0073] The microalga Euglena cultured in the f ~ sstte p is excellent in
an amount of paramylon accumulated, but has a low efficiency of the
wax ester production in the anaerobic fermentation. The second step
can improve the efficiency of the wax ester production of the microalga
10 Euglena in the anaerobic fermentation and then produce the wax ester
by the anaerobic fermentation.
[0074] The anaerobic fermentation is performed by keeping the
microalga Euglena under an anaerobic condition. Here the anaerobic
condition means that the dissolved oxygen concentration of the
15 treatment solution containing the microalga Euglena is 0.03 mglL or
less.
[0075] In the second step, it is preferable that the nutrient be added to
the treatment solution 3 hours before the dissolved oxygen
concentration of the treatment solution is adjusted to 0.03 mg/L or less,
20 and it is more preferable that the nutrient be added to the treatment
solution 1 hour before the dissolved oxygen concentration of the
treatment solution is adjusted to 0.03 m a or less. In other words, it is
preferable that in the second step, the dissolved oxygen concentration of
the treatment solution is adjusted to 0.03 m a or less within 3 hours
25 (more preferably within 1 hour) after the nutrient is added to the
treatment solution.
[0076] The nutrient may be a nitrogen source, a carbon source, or a
mixture of a nitrogen source and a carbon source.
[0077] Examples of the nitrogen source include ammonium compounds
such as diammonium hydrogenphosphate and ammonium sulfate; and
5 amino acids such as glycine and glutamic acid; among these,
ammonium compounds are preferable.
[0078] Examples of the carbon source include saccharides such as
glucose and hctose; alcohols such as ethanol; organic substances such
as malic acid; and amino acids such as glutamic acid; among these,
10 saccharides are preferable, and glucose is more preferable.
[0079] It is preferable that the amount of the nitrogen source to be
added as the nutrient be 7 to 15 mg/L of the treatment solution in terms
of the mass of ammonium ion where nitrogen atoms contained in the
nitrogen source are converted into ammonium ions, and it is more
15 preferable that the amount be 8 to 12 mg/L of the treatment solution in
terms of the mass of ammonium ion where nitrogen atoms contained in
the nitrogen source are converted into ammonium ions.
[0080] It is preferable that the amount of the carbon source to be added
as the nutrient be 0.2 to 2.0 g/L of the treatment solution, and it is more
20 preferable that the amount be 0.5 to 1.5 g/L of the treatment solution.
[0081] Usually Euglena cannot assimilate nitrate nitrogen; if Euglena is
modified by gene recombination techniques or the like to assimilate
nitric acid, it is thought that nitrate nitrogen absorbed fiom an outside of
the cells is metabolized into arnmoniacal nitrogen; in this case, the
25 nitrogen source includes nitric acid compounds.
[0082] The anaerobic fermentation can be performed, for example, by
flowing an inert gas such as nitrogen gas and argon gas into the
treatment solution to reduce the dissolved oxygen concentration of the
treatment solution to 0.03 mg/L or less. The anaerobic fermentation
can be also performed by reducing the dissolved oxygen concentration
5 of the treatment solution by, for example, condensing the treatment
solution to increase the density of cells.
[0083] It is preferable that the fermentation temperature in the
anaerobic fermentation be 20 to 30°C, and it is more preferable that the
temperature be 25 to 2S°C.
10 [0084] The fermentation time in the anaerobic fermentation may be 24
to 120 hours, and preferably 48 to 96 hours.
[0085] In the anaerobic fermentation, irradiation with light is not
always necessary. Adjustment of the pH of the treatment solution is
not always necessary, and the pH can be in the range of 3 to 7, for
15 example.
[0086] At least part of the paramylon accumulated in the microalga
Euglena is converted into the wax ester by the anaerobic fermentation.
The wax ester can be extracted from the microalga Euglena by a known
method after the anaerobic fermentation. Specifically, for example, the
20 microalga Euglena is recovered by centrifugation or the like, and is
freeze dried to form dry powder; the wax ester can be extracted from the
dry powder with an organic solvent.
[0087] Here in the anaerobic fermentation, diglyceride and triglyceride
may be generated in addition to the wax ester. In this case, mixed oils
25 and fats containing the wax ester, diglyceride, and triglyceride can be
obtained by the extraction operation. The mixed oils and fats may be
used as they are as the raw material oil in the third step, or wax ester
may be further separated from the mixed oils and fats and be fed to the
third step.
[0088] A specific aspect of the second step will be shown below.
5 [0089] In this aspect, first, 0.164 g (equivalent to 10 m a ) of
(w4)2m0as4 t)he nitrogen source per 1 L culture solution is added to
the culture solution produced in the first step. Depending on the case,
1 g of glucose as the carbon source per 1 L culture solution is added
instead of or in addition to the nitrogen source.
10 [0090] The culture solution is condensed to approximately 114 in terms
of the volume ratio with a centrifuge, and 400 mL of the condensed
solution is placed in a tall beaker having a volume of 600 mL. Next,
nitrogen gas is flowed at a flow rate of 200 mL1min for approximately
30 minutes to reduce the dissolved oxygen concentration of the
15 condensed solution to 0.03 mgL or less. Preferably, the dissolved
oxygen concentration is reduced to 0.01 m a or less.
[0091] After nitrogen gas is flowed, the top of the flask is covered with
a Parafilm, and the entire flask is covered with an aluminum foil to be
shielded against light; the flask is left to stand at room temperature (26
20 to 27OC for 3 days to perform anaerobic fermentation. After the
anaerobic fermentation, the wax ester can be recovered by a known
method.
[0092] (Third step)
The third step is a step of hydrotreating a raw material oil
25 containing the wax ester produced in the second step to produce a fuel
oil base.
[0093] It is only necessary for the raw material oil to contain the wax
ester produced in the second step, and the raw material oil may contain,
for example, diglyceride and triglyceride formed in the second step in
addition to the wax ester.
5 [0094] In the third step, the hydrotreating conditions and the like can be
properly varied according to the characteristics of the raw material oil
and those of the target fuel oil base. For example, in the third step, the
raw material oil can be subjected to the hydrorefming treatment and the
hydroisomerization treatment as hydrotreating.
10 [0095] Hereinafter, an aspect of the hydrorefining treatment and
hydroisomerization treatment particularly suitable for production of the
fuel oil base for an aviation fuel from the raw material oil containing the
wax ester produced through the first step and the second step will be
shown.
15 [0096] (Hydrorefming treatment)
The raw material oil fed to the hydrorefming treatment contains
the wax ester produced through the first step and the second step, and
may further contain a sulfur-containing compound depending on cases.
The raw material oil to which the sulfur-containing compound is added
20 can improve the catalyst activity (deoxidation activity) of the catalyst
for the hydrorefining treatment described later.
[0097] Examples of the sulfur-containing compound include sulfide,
disulfide, polysulfide, thiol, thiophene, benzothiophene,
dibenzothiophene, derivatives thereof, and hydrogen sulfide. The
25 sulfur-containing compound added to the raw material oil may be one or
two or more.
[0098] The raw material oil may contain the wax ester produced
through the first step and the second step and a petroleum hydrocarbon
fraction containing a sulfur content, for example. For the petroleum
hydrocarbon eaction containing a sulfur content, fractions produced by
5 a typical petroleum refming step can be used.
[0099] Examples of the petroleum hydrocarbon fsactions include
fractions produced with atmospheric distillation units, vacuum
distillation units, and the like and having a boiling point in a
predetermined range; and fractions produced with
10 hydrodesulphurization units, hydrocrackers, residual oil direct
desulphurization units, fluidized bed catalytic cracking units, and the
like and having a boiling point in a predetermined range. The fractions
produced with the respective apparatuses may be used alone or in
combination by mixing.
15 [0100] It is preferable that the content of the sulfur-containing
compound in the raw material oil (sulfur content in the raw material oil)
be 1 to 50 mass ppm based on the total amount of the raw material oil in
terms of the sulfur atom, it is more preferable that the content be 5 to 30
mass ppm, and it is still more preferable that the content be 10 to 20
20 mass ppm. At a content of 1 mass ppm or more, the effect of
improving the catalyst activity (deoxidation activity) of the catalyst for
the hydrorefming treatment can be remarkably attained. At a content
of 50 mass ppm or less, an excessive increase in the concentration of
sulfur in the gas discharged in the hydrorefining treatment (light gas)
25 and the concentration of sulfur in the hydrocarbon oil after the
hydrorefming treatment can be suppressed.
[0101] The content of the sulfur-containing compound in the raw
material oil refers to the mass content of the sulfur content measured
according to JIS K 2541 "Sulfur content test method" or a method
described in ASTM D 5453.
5 [0102] The sulfur-containing compound may be added to the raw
material oil before a recycled oil described later is blended with the raw
material oil, but it is preferable that the sulfur-containing compound be
added to the raw material oil after the recycled oil is blended with the
raw material oil and before the raw material oil is fed to the
10 hydrorefining treatment. This method can more securely control the
amount of the sulfur content in the raw material oil to be fed to the
hydrorefining treatment. In the present embodiment, the
sulfur-containing compound may be added to the raw material oil in
advance, and the raw material oil may be introduced into a reactor of a
15 hydrorefining treatment unit; or the sulfur-containing compound may be
fed at a previous stage of the reactor when the raw material oil is
introduced into the reactor of the hydrorefining treatment unit.
[0103] For the conditions for the hydrorefining treatment, the
conditions of a hydrogen pressure of 2 to 13 MPa, a liquid hourly space
20 velocity of 0.1 to 3.0 h-', a hydrogedoil ratio of 150 to 1500 NLL, and
a reaction temperature of 150 to 480°C are preferable; the conditions of
a hydrogen pressure of 2 to 13 MPa, a liquid hourly space velocity of
0.1 to 3.0 h-', a hydrogedoil ratio of 150 to 1500 NLL, and a reaction
temperature of 200 to 400°C are more preferable; and the conditions of
25 a hydrogen pressure of 3 to 10.5 MPa, a liquid hourly space velocity of
0.25 to 1.0 h-I, a hydrogedoil ratio of 300 to 1000 NL/L, and a reaction
temperature of 260 to 360°C are still more preferable.
[0104] As the catalyst used in the hydrorefining treatment, a catalyst
having a carrier comprising a porous inorganic oxide containing two or
more elements selected from aluminum, silicon, zirconium, boron,
5 titanium and magnesium, and a metal selected from elements in Groups
6 and 8 in the periodic table and carried on the carrier is suitably used.
[0105] For the carrier of the catalyst used in the hydrorefining
treatment, a porous inorganic oxide comprising two or more elements
selected fiom aluminum, silicon, zirconium, boron, titanium, and
10 magnesium is suitably used. Usually the carrier is a porous inorganic
oxide comprising alumina, and examples of other carrier-forming
components include silica, zirconia, boria, titania, and magnesia.
Desirably, the carrier is a composite oxide comprising alumina and at
least one other forming components, and examples include
15 silica-alumina. The carrier may contain phosphorus as an additional
component. It is preferable that the total content of the components
other than alumina be 1 to 20% by weight, and it is more desirable that
the total content be 2 to 15% by weight. At a total content of the
components other than alumina less than 1% by weight, a sufficient
20 catalyst surface area cannot be attained, and its activity may be reduced;
at a content more than 20% by weight, the acidic substance in the carrier
is increased, and the activity may be reduced by generation of coke. If
phosphorus is contained as a carrier forming component, it is desirable
that the content be 1 to 5% by weight in terms of oxide, and it is more
25 desirable that the content be 2 to 3.5% by weight.
[0106] Raw materials for precursors of silica, zirconia, boria, titania,
and magnesia, which are the carrier forming components other than
alumina, are not particularly limited, and a typical solution containing
silicon, zirconium, boron, titanium, or magnesium can be used. For
example, silicic acid, water glass, silica sol, and the like can be used as
5 silicon; titanium sulfate, titanium tetrachloride, a variety of alkoxide
salts, and the like can be used as titanium; zirconium sulfate, a variety of
alkoxide salts, and the like can be used as zirconium; boric acid and the
like can be used as boron. Magnesium nitrate and the like can be used
as magnesium. Phosphoric acid, alkali metal salts of phosphoric acid,
10 or the like can be used as phosphorus.
[0107] It is desirable that the raw materials for the carrier forming
components other than alumina be added in any one of the steps before
calcination of the carrier. For example, the raw material may be added
to an aluminum aqueous solution in advance to prepare an aluminum
15 hydroxide gel containing these carrier forming components; the raw
material may be added to a prepared aluminum hydroxide gel; or the
raw material may be added in a step of adding water or an acidic
aqueous solution to a commercially available alumina intermediate
product or boehmite powder and kneading these; a method for
20 coexistence of these in preparation of the aluminum hydroxide gel is
more desirable. Although the mechanism to demonstrate the effect of
these carrier forming components other than alumina is not clarified, it
seems that the carrier forming component forms an aluminum
composite-like oxide state, and this may cause an increase in the carrier
25 surface area or an interaction with an active metal to influence the
activity.
[0108] The active metal of the catalyst in the hydrorefining treatment
contains preferably at least one metal selected from metals in Groups 6
and 8 in the periodic table, and more preferably two or more metals
selected from Groups 6 and 8. A hydrotreating catalyst containing at
5 least one metal selected fkom Group 6 and at least one metal selected
from Group 8 as the active metals is also suitable. Examples of a
combination of the active metals include Co-Mo, Ni-Mo, Ni-Co-Mo,
and Ni-W, and these metals are converted into sulfides and used in
hydrotreating.
10 [0109] The content of the active metal, for example, the total amount of
Wand Mo carried is desirably 12 to 35% by weight, and more desirably
15 to 30% by weight based on the weight of the catalyst in terms of
oxide. At a total amount of W and Mo carried of less than 12% by
weight, a reduction in the number of active sites may reduce the
15 activity; at a total amount more than 35% by weight, the metals may not
be effectively dispersed, also reducing the activity. The total amount
of Co and Ni carried is desirably 1.5 to 10% by weight, and more
desirably 2 to 8% by weight based on the weight of the catalyst in terms
of oxide. At a total amount of Co and Ni carried of less than 1.5% by
20 weight, a sufficient cocatalyst effect may not be attained, reducing the
activity; at a total amount more than 10% by weight, the metals may not
be effectively dispersed, also reducing the activity.
[0110] In any one of the above catalysts, a method for carrying the
active metal on the carrier is not particularly limited, and a known
25 method usually used in production of a desulphurization catalyst or the
like can be used. Usually a method for impregnating the carrier of the
catalyst with a solution containing an active metal salt is preferably
used. An equilibrium adsorption method, a Pore-filling method, an
Incipient-wetness method, and the like are preferably used. For
example, the Pore-filling method is a method comprising measuring the
5 pore volume of the carrier in advance and impregnating the carrier with
a metal salt solution having the same volume as that; the impregnation
method is not particularly limited, and the carrier can be impregnated by
a proper method depending on the amount of the metal carried and the
physical properties of the carrier of the catalyst.
10 [Olll] The reactor used in the hydrorefining treatment may be of a
fixed bed type. Namely, hydrogen may flow for or against the raw
material oil; or the reactor may have a plurality of reaction towers to
flow hydrogen for and against of the flow of the raw material oil in
combination. A typical one is a down flow type, which can use a
15 gas-liquid parallel flow method. The reactors may be used alone or in
combination, or a structure in which the inside of a reactor is divided
into a plurality of catalyst beds may be used. The hydrorefined oil
subjected to the hydrorefining treatment in the reactor can be
fractionated into a predetermined fiaction through a gas liquid
20 separation step, a refining step, and the like. At this time, to remove
water and by-produced gases such as carbon monoxide, carbon dioxide,
and hydrogen sulfide generated through the reaction, a gas liquid
separating facility or another by-produced gas removing apparatus may
be provided between reactors or may be used in a product recovering
25 step. Examples of the apparatus for removing byproducts preferably
include a high pressure separator.
[0112] Usually the hydrogen gas is introduced fiom an inlet of a first
reactor with the raw material oil before or after the raw material oil
passes through a heating furnace; separately fiom this, the hydrogen gas
may be introduced between the catalyst beds or the reactors to control
5 the temperature inside of the reactor and keep the hydrogen pressure
across the inner reactor. The hydrogen thus introduced is referred to as
quenched hydrogen. At this time, the proportion of the quenched
hydrogen to the hydrogen introduced with the raw material oil is
desirably 10 to 60% by volume, and more desirably 15 to 50% by
10 volume in the standard state (O°C, 1 atm). At a proportion of the
quenched hydrogen less than 10% by volume, the reaction in the rear
stage reaction site may not sufficiently progress; at a proportion more
than 60% by volume, the reaction near the inlet of the reactor may not
sufficiently progress.
15 [0113] In the present embodiment, in the hydrorefining treatment of the
raw material oil, a specific amount of a recycled oil may be contained in
the raw material oil to suppress the amount of heat generated in the
hydrorefining reactor. It is preferable that the content of the recycled
oil be 0.5 to 5 times the mass of the oils and fats derived fi-om the
20 microalga Euglena (total amount of the wax ester, diglyceride, and
triglyceride), and the ratio can be properly determined within the range
thereof according to the highest use temperature of the hydrorefining
reactor. This is because assuming that these both have the same
specific heat, if these are mixed at 1: 1, an increase in the temperature is
25 half an increase in the temperature when the oils and fats derived from
the microalga Euglena are reacted alone; for this reason, at a ratio
within the above range, reaction heat can be sufficiently reduced. At a
content of the recycled oil more than 5 times the mass of the oils and
fats derived f?om the microalga Euglena, the concentration of the oils
and fats reduces to reduce reactivity and the flow rate in a piping or the
5 like increases to increase load. At a content of the recycled oil less
than 0.5 times the mass of the oils and fats derived fiom the microalga
Euglena, an increase in temperature cannot be sufficiently suppressed.
[0114] A method for mixing the raw material oil with the recycled oil is
not particularly limited; for example, these may be premixed, and the
10 pre-mixture may be introduced into the reactor of the hydrorefining
unit, or the recycled oil may be fed in a fiont stage of the reactor for
introduction of the raw material oil into the reactor. Furthermore,
reactors can be connected to each other in series, and the mixture can be
introduced between the reactors; or a catalyst layer can be divided
15 within a single reactor, and the mixture can be introduced between the
divided catalyst layers.
[0115] It is preferable that the recycled oil contain part of a
hydrorefmed oil produced by removing by-produced water, carbon
monoxide, carbon dioxide, hydrogen sulfide, and the like after the raw
20 material oil is hydrorefined. Furthermore, it is preferable that the
recycled oil contain part of a light fraction, an intermediate fraction, or a
heavy fraction fractionated from the hydrorefined oil and isomerized or
part of an intermediate fraction fractionated i%om the hydrorefmed oil
further isomerized.
25 [0116] (Hydroisomerization treatment)
In this aspect, the hydrorefined oil produced through the
hydrorefining treatment may be subjected to a hydroisomerization
treatment. By performing the hydroisornerization treatment, the
proportion of isoparaftin contained in the he1 oil base can be increased
to improve low temperature performance.
5 [0117] It is preferable that the content of the sulfur content contained in
the hydrorefmed oil, which is the raw material oil used in the
hydroisomerization treatment, be 1 mass ppm or less, and it is more
preferable that the content be 0.5 mass ppm. At a content of the sulfur
content more than 1 mass ppm, progression of the hydroisomerization
10 may be prevented. In addition, for the same reason, the sulfur content
needs to be sufficiently low in the reaction gas containing the hydrogen
introduced with the hydrogenated oil, it is preferable that the
concentration be 1 volume ppm or less, and it is more preferable that the
concentration be 0.5 volume ppm or less.
15 [0118] It is desirable that the hydroisomerization treatment be
performed in the presence of hydrogen under the conditions of a
hydrogen pressure of 1 to 5 MPa, a liquid hourly space velocity of 0.1 to
3.0 h-', a hydrogedoil ratio of 250 to 1500 NLIL, and a reaction
temperature of 200 to 360°C, it is more desirable that the
20 hydroisomerization treatment be performed under the conditions of a
hydrogen pressure of 0.3 to 4.5 MPa, a liquid hourly space velocity of
0.5 to 2.0 h-', a hydrogedoil ratio of 380 to 1200 NLIL, and a reaction
temperature of 220 to 350°C, and it is still more desirable that the
hydroisomerization treatment be performed under the conditions of a
25 hydrogen pressure of 0.5 to 4.0 m a , a liquid hourly space velocity of
0.8 to 1.8 h-', a hydrogedoil ratio of 350 to 1000 NLIL, and a reaction
temperature of 250 to 340°C.
[0119] For the catalyst used in the hydroisomerization treatment, a
catalyst comprising a carrier comprising a porous inorganic oxide
composed of a substance selected fiom aluminum, silicon, zirconium,
5 boron, titanium, magnesium and zeolite, and at least one metal selected
form elements in Group 8 in the periodic table and carried on the carrier
is suitably used.
[0120] Examples of the porous inorganic oxide used as the carrier of
the hydroisomerization treatment catalyst include alumina, titania,
10 zirconia, boria, silica, or zeolite; in this aspect, among these, porous
inorganic oxides composed of at least one selected form titania,
zirconia, boria, silica, and zeolite and alumina are preferable. The
production method is not particularly limited; any preparation method
can be used using a raw material corresponding to each element in a
15 state of a variety of sols, salt compounds, or the like. Furthermore, a
composite hydroxide or composite oxide such as silica alumina, silica
zirconia, alumina titania, silica titania, and alumina boria may be
prepared once, and an alumina gel thereof, a hydroxide thereof, or a
proper solution thereof may be added at any step of the preparation
20 process to prepare the porous inorganic oxide. Alumina and the other
oxide can be contained in any proportion to the carrier; the proportion of
alumina is preferably 90% by mass or less, more preferably 60% by
mass or less, more preferably 40% by mass or less, preferably 10% by
mass or more, and more preferably 20% by mass or more.
25 [0121] Zeolite is crystalline aluminosilicate, and examples thereof
include faujasite, pentasil, mordenite, TON, MIT, and *MRE; those
ultrastabilized by a predetermined hydrothermal treatment andlor an
acid treatment or those having an adjusted content of alumina in zeolite
can be used. Preferably faujasite and mordenite, particularly
preferably a Y type and a beta type are used. For the Y type, those
5 ultrastabilized are preferable; zeolite ultrastabilized by the hydrothermal
treatment has an original pore structure called micropore of 20
angstroms or less, and in addition to this, new pores in the range of 20
to 100 angstroms are formed. For the hydrothermal treatment
conditions, known conditions can be used.
10 [0122]For the active metal used in the catalyst for the
hydroisomerization treatment, at least one metal selected fiom elements
in Group 8 in the periodic table is used. Among these metals, it is
preferable that at least one metal selected form Pd, Pt, Rh, Ir, Au, and Ni
be used, and it is more preferable that these be used in combination.
15 Examples of a suitable 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, combinations
of Pd-Pt, Pd-Ni, Pt-Ni, Pd-Ir, Pt-Rh, Pt-Ir, Rh-Ir, Pd-Pt-Rh, Pd-Pt-Ni,
and Pd-Pt-Ir are more preferable, and combinations of Pd-Pt, Pd-Ni,
20 Pt-Ni, Pd-Ir, Pt-Ir, Pd-Pt-Ni, and Pd-Pt-Ir are still more preferable.
[0123] It is preferable that the total content of the active metals be 0.1
to 2% by mass based on the mass of the catalyst in terms of the metal, it
is more preferable that the total content of the active metals be 0.2 to
1.5% by mass based on the mass of the catalyst, it is still more
25 preferable that the total content of the active metals be 0.5 to 1.3% by
mass based on the mass of the catalyst. At a total amount of the metals
carried less than 0.1% by mass, the active sites are reduced, and
sufficient activity tends not to be attained. At a total amount more than
2% by mass, the metals are not effectively dispersed, and sufficient
activity tends not to be attained.
5 [0124] In any one of the catalysts used in the hydroisomerization
treatment, the method for carrying the active metal on the carrier is not
particularly limited, a known method usually used in production of a
desulphurization catalyst can be used. Usually, a method comprising
impregnating a carrier of a catalyst with a solution containing an active
10 metal salt is preferably used. 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 in
which the pore volume of the carrier is measured in advance, and the
carrier is impregnated with a metal salt solution having the same
15 volume as that; the impregnation method is not particularly limited, and
the carrier can be impregnated by a proper method depending on the
amount of the metal to be carried and the physical properties of the
carrier of the catalyst.
[0125] It is preferable that before the isomerization treatment catalyst
20 used in this aspect is fed to the reaction, the active metal contained in
the catalyst be reduced. The reduction conditions are not particularly
limited, and the active metal is reduced by a treatment under a hydrogen
stream at a temperature of 200 to 400°C. It is preferable that the
treatment is performed preferably in the range of 240 to 380°C. At a
25 reduction temperature less than 200°C, the reduction of the active metal
does not sufficiently progress, and hydrodeoxidation and
hydroisomerization activity may not be exhibited. At a reduction
temperature more than 400°C, aggregation of the active metal
progresses, and the activity may also not be exhibited.
[0126] The reactor used in the hydroisomerization treatment may be of
5 a fixed bed type. Namely, hydrogen may flow for or against the raw
material oil; or the reactor may have a plurality of reaction towers to
flow hydrogen for and against of the flow of the raw material oil in
combination. A typical one is a down flow type, which can use a
gas-liquid parallel flow method. The reactors may be used alone or in
10 combination, or a structure in which the inside of a reactor is divided
into a plurality of catalyst beds may be used.
[0127] Usually the hydrogen gas is introduced &om an inlet of a first
reactor with the raw material oil before or after the raw material oil
passes through a heating furnace; separately fiom this, the hydrogen gas
15 may be introduced between the catalyst beds or the reactors to control
the temperature inside of the reactor and keep the hydrogen pressure.
across the inner reactor. The hydrogen thus introduced is referred to as
quenched hydrogen. At this time, the proportion of the quenched
hydrogen to the hydrogen introduced with the raw material oil is
20 desirably 10 to 60% by volume, and more desirably 15 to 50% by
volume in the standard state (O°C, 1 atm). At a proportion of the
quenched hydrogen less than 10% by volume, the reaction in the rear
stage reaction site may not sufficiently progress; at a proportion more
than 60% by volume, the reaction near the inlet of the reactor may not
25 sufficiently progress.
[0128] The hydroisomerized oil produced after the hydroisomerization
treatment step may be fractionated into several fractions with a
rectifying column when necessary. For example, the hydroisomerized
oil may be fiactionated into gas, a light fiaction such as naphtha
fraction, an intermediate ffaction such as kerosene, jet fuels, and a gas
5 oil fraction, and a heavy fiaction such as residues. In this case, it is
preferable that the cut temperature of the light fiaction and the
intermediate fiaction be 100 to 200°C, it is more preferable that the cut
temperature be 120 to 180°C, it is still more preferable that the cut
temperature be 120 to 160°C, and it is further still more preferable that
10 the cut temperature be 130 to 150°C. It is preferable that the cut
temperature of the intermediate fraction and the heavy fraction be 250
to 360°C, it is more preferable that the cut temperature be 250 to 320°C,
it is still more preferable that the cut temperature be 250 to 300°C, and
it is further still more preferable that the cut temperature be 250 to
15 280°C. By reforming part of such a light hydrocarbon fraction to be
generated in a steam reforming apparatus, hydrogen can be produced.
The hydrogen thus produced has carbon neutrality because the raw
material used in the steam reforming is the hydrocarbon derived from a
biomass, and can reduce the load on the environment. The
20 intermediate fraction produced by fractionating the hydroisomerized oil
can be suitably used as the fuel oil base for an aviation hel.
[O 1291 (Fuel oil base)
The he1 oil base according to the present embodiment is a fuel
oil base produced by the production method. Hereinafter, one aspect
25 of a fuel oil base suitable for the fuel oil base for an aviation fuel
(hereinafter referred to as an "aviation he1 oil base") will be described
in detail.
[0130] It is preferable that the aviation fuel oil base satisfy the
characteristics of the base oil specified in "A2. Synthesized Paraffinic
Kerosine From Hydroprocessed Esters and Fatty Acids" of ASTM
5 D7566-11 "Standard Specification for Aviation Turbine Fuel Containing
Synthesized Hydrocarbons," and it is more preferable that suitable
ranges in the following conditions (I) to (22) be satisfied.
(1) boiling point range: 140 to 300°C,
(2) distillation temperature at 10% distillation (TIO): 20S°C or less,
10 (3) distillation end point (FEP): 300°C or less,
(4) difference between distillation temperature at 90% distillation (T90)
and distillation temperature at 10% distillation (T10): 22°C or more,
(5) total acid value: 0.015 mgKOWg or less,
(6) flash point: 38OC or more,
15 (7) density at lS°C: 730 kg/m30r more and 770 kg/m3 or less,
(8) fkeezing point: -45°C or less,
(9) existing gum content: 7 mg1100 mL or less,
(10) thermal stability---pressure difference: 3.3 kPa or less,
(1 1) thermal stability---tube accumulation degree: less than 3,
20 (12) isoparaffin content: 80% by mass or more (more preferably 85% by
mass or more),
(13) isoparaffin content having two or more branching: 17% by mass
or more (more preferably 20% by mass or more),
(14) aromatic content: 0.1% by mass or less,
25 (15) cycloparaffin content: 15% by mass or less,
(16) olefin content: less than 0.1% by mass,
(17) sulfur content: less than 1 mass ppm,
(18) oxygen content: less than 0.1% by mass,
(10) nitrogen content: 2 mass ppm or less,
(20) moisture content: 75 mass pprn or less,
5 (21) chlorine content: 1 mass ppm or less,
(22) metal content (Al, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb,
Pd, Pt, Sn, Sr, Ti, V, Zn): each 0.1 mass ppm or less.
LO13 11 (Boiling point range)
It is preferable that the boiling point of the aviation fuel oil base
10 be in the range of 140 to 300°C. At a boiling point in the range of 140
to 300°C, the combustibility as the aviation fuel oil can be more
securely satisfied. It is preferable that for the distillation
characteristics of the aviation he1 oil base, TI0 be 205°C or less, and it
is more preferable that TI0 be 200°C or less from the viewpoint of
15 evaporation properties. It is preferable that FEP be 300°C or less, it is
more preferable that FEP be 290°C or less, and it is still more preferable
that FEP be 280°C or less from the viewpoint of combustion
characteristics (burnout properties). The difference between T90 and
T10 (T90 - T10) is 22°C or more, and it is more preferable that it be
20 30°C or more from the viewpoint of ensuring combustibility under
various weather conditions. The distillation characteristics here mean
the value measured according to JIS K2254 "Petroleum
products-distillation test method."
[0132] (Total acid value)
25 It is preferable that the total acid value of the aviation fuel oil
base be 0.015 mgKOWg or less, it is more preferable that the total acid
value be 0.01 mgKOWg or less, it is still more preferable that the total
acid value be 0.008 mgKOWg or less, and it is further still more
preferable that the total acid value be 0.005 mgKOWg or less fiom the
viewpoint of corrosiveness. The total acid value here means the value
5 measured according to JIS K2276 "Total acid value test method."
[0133] (Flash point)
It is preferable that the flash point of the aviation fuel oil base be
38°C or more, it is more preferable that the flash point be 40°C or more,
and it is still more preferable that the flash point be 45°C or more from
10 the viewpoint of safety. The flash point here means the value
measured according to JIS K2265 "Crude oil and petroleum
products-flash point test method-tag sealed flash point test method."
[0134] (Density)
It is preferable that the density at 15°C of the aviation fuel oil
15 base be 730 kg/m3 or more, and it is more preferable that the density be
735 kg/m3 or more from the viewpoint of a fuel consumption rate. It is
preferable that the density be 770 kg/m3 or less, and it is more
preferable that the density be 765 kg/m3 or less &om the viewpoint of
combustibility. The density at 15°C here means the value measured
20 according to JIS K2249 "Crude oil and petroleum products-density test
method and density~mass~volumceo nversion table."
[0135] (Freezing point)
It is preferable that the freezing point of the aviation fuel oil
base be -45°C or less, it is more preferable that the ffeezing point be
25 -48°C or less, and it is still more preferable that the freezing point be
-50°C or less fiom the viewpoint of preventing a reduction in feed of the
fuel due to freezing of the fuel exposed to low temperatures during
flying. The freezing point here means the value measured according to
JIS K2276 "Freezing point test method."
[0136] (Existing gum content)
5 It is preferable that the existing gum content of the aviation fuel
oil base be 7 mg/100 mL or less, it is more preferable that the existing
gum content be 5 mg/100 mL or less, and it is still more preferable that
the existing gum content be 3 mg/100 mL or less from the viewpoint of
preventing deficits due to generation of precipitates in a fuel
10 introduction system or the like. The existing gum content here means
the value measured according to JIS K2261 "Gasoline and aviation fuel
oil existing gum test method."
[0137] (Thermal stability)
It is preferable that as the thermal stability of the aviation fuel
15 oil base (at 32S°C for 2.5 hours), a pressure difference be 3.3 kl'a or
less, and a tube accumulation evaluation value (tube accumulation
degree) be less than 3 from the viewpoint of, for example, preventing
clogging of the fuel filter due to generation of precipitates during
exposure to high temperatures. The pressure difference and the tube
20 accumulation degree as the thermal stability here mean the values
measured according to ASTM D3241 "Standard Test Method for
Thermal Oxidation Stability ofAviation Turbine Fuels," respectively.
[0138] (Isoparaffm content and 2-branched isoparafin content)
It is preferable that the content of isoparafin in the aviation fuel
25 oil base be 80% by mass or more, and 85% by mass or more is more
preferable to satisfy the specification of low temperature performance as
the aviation fuel oil. It is preferable that the content of isoparaffm
having two or more branchings be 17% by mass or more, and 20% by
mass or more is more preferable to satisfy the specification of low
temperature performance as the aviation fuel oil. The content of
5 isoparaffm and the content of isoparaffin having two or more
branchings here mean the values measured with a gas chromatograph
and a time of flight mass spectrometer (GC-TOFMS), respectively.
[0139] (Aromatic content and cycloparaffin content)
It is preferable that the aromatic content in the aviation fuel oil
10 base be 0.1% by mass or less from the viewpoint of combustibility
(prevention of generation of soot). It is preferable that the
cycloparaffm content be 15% by mass or less, it is more preferable that
the cycloparaffin content be 12% by mass or less, and it is still more
preferable that the cycloparaffin content be 10% by mass or less from
15 the viewpoint of ensuring combustibility. The aromatic content and
cycloparaffin content here mean the values measured according to
ASTM D2425 "Standard Test Method for Hydrocarbon Types in Middle
Distillates by Mass Spectrometry."
[0140] (Olefm content)
20 It is preferable that the olefin content in the aviation fuel oil base
be 0.1% by mass or less to prevent a reduction in oxidation stability.
The olefm content here means the value measured according to ASTM
D2425 "Standard Test Method for Hydrocarbon Types in Middle
Distillates by Mass Spectrometry."
25 [0141] (Sulhr content)
It is preferable that the sulhr content in the aviation fuel oil base
be 1 mass pprn or less, it is more preferable that the sulfur content be
0.8 mass pprn or less, and it is still more preferable that the sulfur
content be 0.6 mass pprn or less fiom the viewpoint of prevention of
corrosiveness. The sulfur content here means the value measured
5 according to JIS K2541 "Crude oil and petroleum product sulfur content
test method."
[0142] (Oxygen content)
It is preferable that the oxygen content in the aviation fuel oil
base be 0.1% by mass or less fiom the viewpoint of preventing a
10 reduction in the amount of heat generated. The oxygen content here
means the oxygen content measured according to UOP 649-74 "Total
Oxygen in Organic Materials by Pyrolysis-Gas Chromatographic
Technique."
[0143] (Nitrogen content)
15 It is preferable that the nitrogen content in the aviation fuel oil
base be 2 mass pprn or less, and it is more preferable that the nitrogen
content be 1.5 mass ppm or less from the viewpoint of preventing
corrosion. The nitrogen content here means the value measured
according to ASTM D4629 "Standard Test Method for Trace Nitrogen
20 in Liquid Petroleum Hydrocarbons by Syringehnlet Oxidative
Combustion and Chemiluminescence Detection."
101441 (moisture content)
It is preferable that the moisture content in the aviation fuel oil
base be 75 mass pprn or less, and it is more preferable that the moisture
25 content be 50 mass ppm or less from the viewpoint of deicing. The
moisture content here means the value measured according to ASTM
D6304 "Standard Test Method for Determination of Water in Petroleum
Products, Lubricating Oils, and Additives by Coulometric Karl Fischer
Titration."
[0145] (Chlorine content)
5 It is preferable that the chlorine content in the aviation fuel oil
base be 1 mass pprn or less, and it is more preferable that the chlorine
content be 0.5 mass pprn or less from the viewpoint of preventing
corrosion. The chlorine content here means the value measured
according to ASTM D7359 "Standard Test Method for Total Fluorine,
10 Chlorine and Sulfur in Aromatic Hydrocarbons and Their Mixtures by
Oxidative Pyrohydrolytic Combustion followed by Ion Chromatography
Detection (Combustion Ion Chromatography-CIC)."
[0146] (Metal content)
It is preferable that the metal contents in the aviation fuel oil
15 base (Al, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Pd, Pt, Sn, Sr,
Ti, V, Zn) each be 0.1 mass pprn or less from the viewpoint of
suppressing accumulated products within the engine and preventing
wear. The metal content here means the value measured according to
UOP 389 "Trace Metals in Organics by Wet Ash-ICP-AES."
20 [0147] (Aviation fuel oil composition)
The he1 oil composition according to the present embodiment
(hereinafter also referred to as an "aviation fuel oil composition")
contains the aviation fuel oil base, and has a sulfur content of 10 mass
pprn or less and a freezing point of -47°C or less. In the present
25 embodiment, the aviation he1 oil base can be mixed with a hydrorefined
oil refmed from a crude oil or the like (also referred to as a "petroleum
base oil") to produce an aviation fuel oil composition satisfying
predetermined performance. The content of the aviation fuel oil base
to the aviation fuel oil composition is not particularly limited, and it is
preferable that the content be 1% by volume or more, it is more
5 preferable that the content be 3% by volume or more, and it is still more
preferable that the content be 5% by volume or more from the viewpoint
of reducing the environmental load. It is preferable that the content be
50% by volume or less from the viewpoint of capable of easily
producing a predetermined aviation he1 oil composition specified in
10 ASTM D7566-11.
[0148] Examples of the petroleum base oil produced by refining a crude
oil or the like include fractions produced by atmospheric distillation or
vacuum distillation of a crude oil, and fractions produced by a reaction
such as hydrodesulphurization, hydrocrackiing, fluidized catalytic
15 cracking, and catalytic reforming. Furthermore, the petroleum base oil
produced by refining a crude oil or the like may be a compound derived
fr0m.a chemical or a synthetic oil produced through a Fischer-Tropsch
reaction. It is preferable that the synthetic oil produced through the
Fischer-Tropsch reaction satisfy the characteristics of the base oil
20 specified in "Al. Fischer-Tropsch Hydroprocessed Synthesized
Paraffinic Kerosine" of ASTM D7566-11 "Standard Specification for
Aviation Turbine Fuel Containing Synthesized Hydrocarbons." It is
preferable that the lower limit of the content of the petroleum base oil
produced by refining a crude oil or the like to the aviation fuel oil
25 composition be 50% by volume or more and the upper limit be 99% by
volume or less, it is more preferable that the upper limit be 97% by
volume or less, and it is still more preferable that the upper limit be 95%
by volume or less.
[0149] In the aviation fuel oil composition, a variety of additives used
for the aviation fuel oil in the related art can be used. Examples of the
5 additives include one or more additives selected fiom an antioxidant, an
antistatic agent, a metal deactivator, and a deicing agent.
[0150] To suppress generation of the gum in the aviation fuel oil
composition, as the antioxidant, a mixture of 75% or more of
N,N-diisopropylparaphenylenediamine, 2,6-ditertiary butyl phenol,
10 2,6-ditertiary butyl-4-methylphenol,
2,4-dimethyl-6-tertiary-butylphenol,a nd 2,6-ditertiary-butylphenol and
25% or less of tertiary- and tritertiary-butylphenols, a mixture of 72% or
more of 2,4-dimethyl-6-tertiary-butylphenol and 28% or less of
monomethyl- and dimethyl-tertiarybutylphenols, a mixture of 55% or
15 more of 2,4-dimethyl-6-tertiary-butylphenol, 15% of
2,6-ditertiarybutyl-4-methylphenol, and 30% or less of tertiary- and
ditertiary-butylphenols, and the like can be added in the range of 17.0
mg/L or more and 24.0 mg/L or less.
[0151] To prevent accumulation of static electricity caused by friction
20 of the aviation fuel oil with an inner wall of a pipe when the oil flows in
a fuel pipe system at a high speed and to enhance electric conductivity,
as the antistatic agent, STADIS450 made by Innospec Inc. or the like
can be added at the initial amount in the range of 3 mg/L or less and the
cumulative amount in the range of 5 m a or less. In this application,
25 the initial amount means the amount of the additive to be added during
production of the fuel oil, and the cumulative amount means the total
cumulative amount of the additive added to the fuel oil before use.
[0152] To prevent the free metal component contained in the aviation
fuel oil from reacting to make the fuel unstable, as the metal deactivator,
N,N-disalicylidene-l,2-propanediamine or the like can be added such
5 that the initial amount is in the range of 2 mgL or less and the
cumulative amount is in the range of 5.7 mgL or less.
[0153] To prevent a slight amount of water contained in the aviation
fuel oil from freezing to clog the pipe, as the deicing agent, ethylene
glycol monomethyl ether or the like can be added in the range of 0.1 to
10 0.15% by volume.
[0154] Furthermore, any additive such as an antistatic agent, a
corrosion suppressing agent, and a bactericide can be properly blended
with the aviation fuel oil composition as long as within the scope of the
present invention.
15 [0155] It is preferable that the aviation fuel oil composition satisfy the
specified value specified in ASTM D7566-11 "Aviation turbine he1 oil"
("Jet A" or "Jet A-I").
[0156] (Sulfur content)
It is preferable that the sulfur content in the aviation fuel oil
20 composition be 10 mass ppm or less, it is more preferable that the sulfur
content be 8 mass ppm or less, and it is still more preferable that the
sulfur content be 5 mass ppm or less from the viewpoint of
corrosiveness. Also fiom the viewpoint of corrosiveness, it is
preferable that the mercaptan sulfur content be 0.003% by mass or less,
25 it is more preferable that the mercaptan sulfur content be 0.002% by
mass or less, and it is still more preferable that the mercaptan sulfur
content be 0.001% by mass or less. The sulfur content here means the
value measured according to JIS K2541 "Crude oil and petroleum
product sulfur content test method" and the mercaptan sulfur content
means the value measured according to JIS K2276 "Mercaptan sulfur
5 content test method (potentiometric titration method)."
[O 1571 (Freezing point)
It is preferable that the freezing point of the aviation fuel oil
composition be -47°C or less, it is more preferable that the freezing
point be -48°C or less, and it is still more preferable that the freezing
10 point be -50°C or less from the viewpoint of preventing a reduction in
feed of the fuel due to freezing of the fuel exposed to low temperatures
during flying. The freezing point here means the value measured
according to JIS K2276 "freezing point test method."
[0158] (Density)
15 It is preferable that the density at 15°C of the aviation fuel oil
composition be 775 kg/m3 or more, and it is more preferable that the
density at 15°C be 780 kg/m3 or more from the viewpoint of a fuel
consumption rate. It is preferable that the density at 15OC be 839
kg/m3 or less, it is more preferable that the density at 15OC be 830 kg/m3
20 or less, and it is still more preferable that the density at 15°C be 820
kg/m3 or less from the viewpoint of combustibility. The density at
15°C here means the value determined according to JIS K2249 "Crude
oil and petroleum product-density test method and density~mass~volume
conversion table."
25 [0159] (Distillation characteristics)
It is preferable that as the distillation characteristics of the
aviation fuel oil composition, the 10% by volume distillation
temperature (T10) be 205°C or less, and it is more preferable that T10
be 200°C or less from the viewpoint of evaporation properties. It is
preferable that the end point (FEP) be 300°C or less, and it is more
5 preferable that the FEP be 298°C or less from the viewpoint of
combustion characteristics (burnout properties). The distillation
characteristics here mean the value measured according to JIS K2254
"Petroleum product-distillation test method."
[0160] (Existing gum content)
10 It is preferable that the existing gum content in the aviation fuel
oil composition be 7 mg/100 mL or less, it is more preferable that the
existing gum content be 5 mg/100 rnL or less, and it is still more
preferable that the existing gum content be 3 mg/100 mL or less from
the viewpoint of preventing deficits due to generation of precipitates in
15 a fuel introduction system or the like. The existing gum content here
means the value measured according to JIS K2261 "Gasoline and
aviation fie1 oil existing gum test method."
[0161] (Net calorific value)
It is preferable that the net calorific value of the aviation fuel oil
20 composition be 42.8 MJkg or more, and it is more preferable that the
net calorific value be 43 MJkg or more from the viewpoint of a fuel
consumption rate. The net calorific value here means the value
measured according to JIS K2279 "Crude oil and fuel oil calorific value
test method."
25 [0162] (Kinematic viscosity)
It is preferable that the kinematic viscosity at -20°C of the
aviation fuel oil composition be 8 mm2/s or less, it is more preferable
that the kinematic viscosity at -20°C be 7 mm2/s or less, and it is still
more preferable that the kinematic viscosity at -20°C be 5 mm21s or less
fiom the viewpoint of the fluidity of the fuel pipe and achievement of
5 uniform fuel jetting. The kinematic viscosity here means the value
measured according to JIS K2283 "Crude oil and petroleum product
kinematic viscosity test method."
[0163] (Corrosion of copper plate)
It is preferable that the corrosion of a copper plate by the
10 aviation fuel oil composition be 1 or less from the viewpoint of the
corrosiveness of the fuel tank and the pipe. The corrosion of copper
plate here means the value measured according to JIS K2513
"Petroleum product-copper plate corrosion test method."
[0164] (Aromatic content)
15 It is preferable that the aromatic content in the aviation fuel oil
composition be 25% by volume or less, and it is more preferable that the
aromatic content be 20% by volume or less fiom the viewpoint of
combustibility (prevention of generation of soot). Meanwhile, 8% by
volume or more is preferable, 10% by volume or more is more
20 preferable from the viewpoint of controlling of swelling properties of
the rubber. The aromatic content here means the value measured
according to JIS K2536 "Fuel oil hydrocarbon component test method
(fluorescent indicator adsorption method)."
[0165] (Smoke point)
25 It is preferable that the smoke point of the aviation fuel oil
composition be 25 mm or more, it is more preferable that the smoke
point be 27 mm or more, and it is still more preferable that the smoke
point be 30 rnm or more from the viewpoint of combustibility
(prevention of generation of soot). The smoke point here means the
value measured according to JIS K2537 "Fuel oil smoke point test
5 method."
[0166] (Flash point)
It is preferable that the flash point of the aviation fuel oil
composition be 40°C or more, it is more preferable that the flash point
be 42°C or more, and it is still more preferable that the flash point be
10 45°C or more from the viewpoint of safety. The flash point here
means the value measured according to JIS K2265 "Crude oil and
petroleum product-flash point test method-tag sealed flash point test
method."
[0167] (Total acid value)
15 It is preferable that the total acid value of the aviation fuel oil
composition be 0.01 mgKOWg or less, it is more preferable that the
total acid value be 0.008 mgKOWg or less, it is still more preferable
that the total acid value be 0.005 mgKOWg or less, and it is further still
more preferable that the total acid value be 0.003 mgKOWg or less
20 from the viewpoint of corrosiveness. The total acid value here means
the value measured according to JIS IS2276 "Total acid value test
method."
[0168] (Thermal stability)
It is preferable that as the thermal stability of the aviation fuel
25 oil composition (at 260°C for 2.5 hours), a pressure difference be 3.3
kPa or less, and a tube accumulation evaluation value (tube
accumulation degree) be less than 3 fiom the viewpoint of, for example,
preventing clogging of the fuel filter due to generation of precipitates
during exposure to high temperatures. The pressure difference and the
tube accumulation degree as the thermal stability here mean the values
5 measured according to ASTM D3241 "Standard Test Method for
Thermal Oxidation Stability of Aviation Turbine Fuels," respectively.
[0169] (Conductivity)
It is preferable that the conductivity of the aviation fuel oil
composition be 50 pS/m or more, and it is more preferable that the
10 conductivity be 80 pS/m or more from the viewpoint of preventing
charge. It is preferable that the conductivity be 600 pS/m or less, and
it is more preferable that the conductivity be 500 pS/m or less fiom the
viewpoint of ensuring separation of water. The conductivity here
means the value measured according to JIS K2276 "Conductivity test
15 method."
[0 1701 (Lubricity)
It is preferable that the diameter of a wear track of the aviation
fuel oil composition measured by the BOCLE test method be 0.85 mm
or less, and it is more preferable that the diameter be 0.6 mm or less
20 from the viewpoint of protecting the engine. The diameter of a wear
track measured by the BOCLE test method means the value measured
according to ASTM D5001 "Standard Test Method for Measurement of
Lubricity of Aviation Turbine Fuels by the Ball-on-Cylinder Lubricity
Evaluator (BOCLE)."
25 [0171] As above, a suitable embodiment according to the present
invention has been described, but the present invention is not be limited
to the embodiment.
[0172] In the present invention, the fuel oil base produced by the
production method can also be used in applications other than the
aviation fuel, and can be used in applications such as diesel engines, for
5 example.
[0173] In the present invention, the fuel oil composition containing the
fuel oil base produced by the production method can also be used in
applications other than the aviation fuel, and can be used in applications
such as diesel engines, for example.
10 [0174] In one aspect, the present invention can be a method for
producing Euglena containing a wax ester in a high concentration, the
method comprising a first step of aerobically culturing a microalga
Euglena under a nitrogen-deficient condition; and a second step of
keeping the cells under an anaerobic condition, wherein at least the two
15 steps are performed, and prior to the second step, a nutrient is added to
the culture solution subjected to the first step.
[0175] In other aspect, the present invention can also be a method for
producing a fuel oil base, comprising a f ~ sstte p of aerobically culturing
a microalga Euglena under a nitrogen-deficient condition; a second step
20 of keeping the cells under an anaerobic condition; and a third step of
hydrotreating a raw material oil containing the wax ester generated in
the second step to produce a fuel oil base, wherein at least the three
steps are performed, and prior to the second step, a nutrient is added to
the culture solution subjected to the first step.
25 [0176] The production methods may be characterized in that the
addition of the nutrient is performed at a timing earlier than the timing
when the dissolved oxygen concentration of the culture solution kept
under an anaerobic condition in the second step is reduced to 0.03 mg/L
or less.
5 Examples
[0177] Hereinafter, the present invention will be described in more
detail based on Examples and Comparative Examples, but the present
invention will not be limited to these Examples.
[0178] (Preparation of catalyst)
10
18.0 g of water glass No. 3 was added to 3000 g of an aluminate
sodium aqueous solution having a concentration of 5% by mass, and the
solution was placed in a container kept at 65OC. In another container
kept at 65"C, 6.0 g of phosphoric acid (concentration: 85%) was added
15 to 3000 g of an aluminum sulfate aqueous solution having a
concentration 2.5% by mass to prepare a solution; to this, the aqueous
solution containing the above aluminate sodium was dropped. The end
point was defined as when the pH of the mixed solution reached 7.0; the
prepared slurry product was filtered through a filter to obtain a cake-like
20 slurry.
[0179] The cake-like slurry was placed in a container to which a reflux
cooler was attached, 150 ml of distilled water and 10 g of 27% aqueous
ammonia solution were added, and these were stirred at 75OC for 20
hours while heating. The slurry was placed in a kneading apparatus,
25 and heated to 80°C or more; the slurry was kneaded while the moisture
content was being removed to prepare a clay-like kneaded product.
The prepared kneaded product was extruded with an extrusion molding
machine into a cylindrical shape having a diameter of 1.5 mm; the
product was dried at llO°C for one hour, and then was calcined at
550°C to prepare a molded carrier.
5 [0180] 50 g of the prepared molded carrier was placed in a recovery
flask; while degassing with a rotary evaporator, an impregnation
solution containing 17.3 g of molybdenum trioxide, 13.2 g of nickel@)
nitrate hexahydrate, 3.9 g of phosphoric acid (concentration: 85%), and
4.0 g of malic acid was injected into the flask. The impregnated
10 sample was dried at 120°C for one hour, and was then calcined at 550°C
to prepare Catalyst A. The physical properties of Catalyst A are shown
in Table 3.
[0181]
50 g of a silica alumina carrier having a silica-alumina ratio
15 (mass ratio) of 70:30 was placed in recovery flask; while degassing with
a rotary evaporator, a tetraammine platinum(I1) chloride aqueous
solution was injected into the flask. The impregnated sample was
dried at llO°C, and was then calcined at 350°C to prepare Catalyst B.
The amount of platinum carried on Catalyst B was 0.5% by mass based
20 on the total amount of the catalyst. The physical properties of Catalyst
B are shown in Table 3.
[OI 821
ZSM-48 zeolite was synthesized by the method described in
Non Patent Literature (Appl. Catal. A, 299 (2006), pp. 167-174). The
25 synthesized ZSM-48 zeolite was dried under an air stream at 9S°C for 3
hours, and was then calcined under an air atmosphere at 550°C for 3
hours to prepare calcined zeolite.
[0183] As an alumina binder, a commercially available boehmite
powder (trade name: CATALOID-AP) was prkpared. The calcined
zeolite was sufficiently kneaded with the boehmite powder formed into
5 a slurry by adding a proper amount of water such that zeolite: alumina
was 70:30 (% by mass); thus, a kneaded product was prepared. The
kneaded product was fed to an extrusion molding machine to prepare a
molded carrier having a cylindrical shape (diameter: 1.5 mm, length: 1
cm). The prepared molded carrier was dried under an air stream at
10 95°C for 3 hours, and was then calcined under an air atmosphere at
550°C for 3 hours.
[0184] 50 g of the calcined molded carrier was placed in a recovery
flask; while degassing with a rotary evaporator, dinitrodiamino platinum
and dinitrodiamino palladium were added, and were impregnated into
15 the molded carrier to prepare an impregnated sample. The amounts of
impregnation were adjusted such that the amounts of platinum and
palladium impregnated were 0.3% by mass and 0.3% by mass based on
the catalyst to be prepared, respectively. The impregnated sample was
dried under an air atmosphere at 120°C for one hour, and was then
20 calcined under an air atmosphere at 550°C to prepare Catalyst C. The
physical properties of Catalyst C are shown in Table 3.
[0185] [Table 31
[0186] (Example 1)
(1-1) Pre-culturing step
The AY culture medium having the composition shown in Table
1 was prepared with deionized water, the pH was adjusted to 3.5 with
dilute sulfbric acid, and autoclave sterilization was performed.
Approximately 2 L of the sterilized AY culture medium was placed 20
cm high in an acrylic culturing container measuring a length of 10 cm, a
width of 10 cm, and a height of 27 cm, and Euglena gracilis Z strains
were planted in the medium.
[0187] The culturing container was placed inside of a thermostat water
bath installed on a magnetic stirrer SRSBlOLA (ADVANTEC Co.,
LTD.), and the medium was stirred at a strength of 300 rpm using a 6
cm stirrer. A metal halide lamp Eye Clean Ace BT (made by Iwasaki
Electric Co., Ltd.) as a light source was placed immediately above the
surface of the culture solution, and its height was adjusted such that the
light illuminating the surface of the culture solution had an intensity of
approximately 900 vmo~(m2.s). The light irradiation time employed
the light and dark cycle in which light was turned on for 12 hours and
then turned off for 12 hours to make the condition close to the outdoor
condition of day and night. As a carbon source, C02 was flowed at a
5 flow rate of 0.1 wm (200 mL/min) and a concentration of 15%.
[OlSS] After the pre-culturing was performed for 3 days using the AY
culture medium, Euglena cells were centrifuged fiom the 2 L culture
solution (2500 rpm, 5 minutes, room temperature), and were washed
with deionized water once to obtain nitrogen-deficient cultured algal
10 bodies.
[0189] (1-2) Nitrogen-deficient culturing step (first step)
The AY culture medium having the composition shown in Table
2 (hereinafter referred to as "nitrogen-deficient AY culture medium" in
some cases) was prepared with deionized water, the pH was adjusted to
15 3.5 with dilute sulfuric acid, and autoclave sterilization was performed.
Approximately 4.5 L of the sterilized nitrogen-deficient AY culture
medium was placed 20 cm high in an acrylic culturing container
measuring a length of 15 cm, a width of 15 cm, and a height of 27 cm;
the algal bodies obtained in (1-1) Pre-culturing step were planted in the
20 medium such that the initial concentration of the algal bodies in the
nitrogen-deficient AY culture medium was 0.3 g/L.
[0190] The culturing container was placed inside of a thermostat water
bath installed on a magnetic stirrer SRSBlOLA (ADVANTEC Co.,
LTD.), and the medium was stirred at a strength of 300 rpm using a 6
25 cm stirrer. A metal halide lamp Eye Clean Ace BT (made by Iwasaki
Electric Co., Ltd.) as a light source was placed immediately above the
surface of the culture solution, and its height was adjusted such that the
light illuminating the surface of the culture solution had an intensity of
approximately 900 pno~(m~.s)T. he light irradiation time employed
the light and dark cycle in which light was turned on for 12 hours and
5 then turned off for 12 hours to make the condition close to the outdoor
condition of day and night. As a carbon source, C02 was'flowed at a
flow rate of 0.1 wm (200 mL1min) and a concentration of 15%.
[0191] The culturing was performed in a light and dark cycle in which
the start of the dark period was defined as the start of culturing, i.e., 0
10 hour; the metal halide lamp was turned on after 12 hours, turned off
after 24 hours, and turned on after 36 hours again.
[0192] (1 -3) Anaerobic fermentation step (second step)
After 47 hours from the start of the culturing in the
nitrogen-deficient AY culture medium, 0.1643 g (equivalent to 10 mgL)
15 of diammonium hydrogenphosphate ((NH4)2m0as4 t)h e nutrient was
added to 1 L of the culture solution.
[0193] Next, after 48 hours fiom the start of the culturing in the
nitrogen-deficient AY culture medium, 2 L of the culture solution was
condensed with a centrifuge into 0.5 L, and the condensed solution was
20 placed in a tall beaker having a volume of 600 mL. The condensed
culture solution was subjected to an anaerobic treatment by flowing
nitrogen gas at a flow rate of 200 mL/min for approximately 30
minutes. The anaerobic treatment was terminated when it was found
that the dissolved oxygen concentration reached 0.01 mg/L or less.
25 [0194] The top of the beaker after the anaerobic treatment was covered
with paraffin, and the entire flask was covered with an aluminum foil to
shield against light, and was left to stand at room temperature for 3 days
to perform anaerobic fermentation. At this time, room temperature
was 26 to 27OC. After the anaerobic fermentation, Euglena cells were
recovered with a centrifugation (2500 rpm, 5 minutes, room
5 temperature); the recovered products were frozen, and were fkeeze dried
to obtain Euglena dried algal bodies. The fkeeze drying was performed
with a f?eeze dryer DRW240DA (ADVANTEC Co., LTD.).
[0195] (1-4) Extraction of oils and fats
Extraction of oils and fats from the Euglena dried algal bodies
10 was performed by the following procedure. First, 0.2 to 0.3 g of the
Euglena dried algal bodies was placed in a sealed container, n-hexane
having a weight 10 times that of the Euglena dried algal bodies was
added, and the mixture was shaken at room temperature (25 to 26OC)
and 200 rpm for one hour. A solid was separated ffom a liquid by
15 filtration, and the cake on the funnel was washed with hexane having a
weight approximately 20 times that of the original dried algal bodies.
The filtrate and the washing liquid were added, and 11-hexane was
distilled with an evaporator whose bath temperature was set at 5S°C;
then, oils and fats were recovered.
20 [0196] The operation was repeated twice, the first and second extracted
oils and fats were collected into one. From the weight of the recovered
oils and fats and the weight of the Euglena dried algal bodies used in
extraction with hexane, the content of oils and fats in the Euglena dried
algal bodies after the anaerobic fermentation was calculated. The
25 content of the oils and fats is as shown in Table 4.
[0197]
In the oils and fats obtained in (1-4), the results of component
15 analysis shown in Table 4 will be shown below in detail.
[0204] Density at 15OC (density@lS°C) means the value measured
according to JIS K2249 "Crude oil and petroleum product-density test
method and densitymass~volumec onversion table."
[0205] C (% by mass) and H (% by mass) in Elemental analysis mean
20 the values measured by the method specified in ASTM D 5291
"Standard Test Methods for Instrumental Determination of
Carbon,Hydrogen, and Nitrogen in Petroleum Products and Lubricants."
[0206] Oxygen content means the value measured by the method such
as UOP 649-74 "Total Oxygen in Organic Materials by Pyrolysis-Gas
25 ChromatographicTechnique."
[0207] Sulfur content means the value measured according to JIS
K2541 "Crude oil and petroleum product sulfur content test method."
[0208] (1-5) Hydrotreating step (third step)
A reaction tube (inner diameter: 20 rnm) filled with Catalyst A
(100 ml) was mounted on a fixed bed flow reaction apparatus
5 countercurrentIy. Subsequently, using a straight run gas oil (sulfur
content: 3% by mass) to which dimethyl disulfide was added, the
catalyst was pre-sulfidized under the conditions of a catalyst layer
average temperature of 300°C, a hydrogen partial pressure of 6 MPa, a
liquid hourly space velocity of 1 h-', and a hydrogenloil ratio of 200
10 NL/L for 4 hours.
[0209] After the pre-sulfidation, part of the hydrogenated oil after
introduction thereof into a high pressure separator described later was
recycled to the oils and fats obtained in (1-4) at an amount of 1 by mass
times the mass of the oils and fats, and dimethyl sulfide was added such
15 that the content of the sulhr content (in terms of the sulfur atom) was
10 mass ppm based on the total amount of a raw material oil; thus, the
raw material oil was prepared.
[0210] The condition for hydrotreating was that the catalyst layer
average temperature (reaction temperature) was 300°C, the hydrogen
20 pressure was 6.0 MPa, the liquid hourly space velocity was 1.0 h-', and
the hydrogenloil ratio was 510 NLL. The treated oil after the
hydrotreating was introduced into the high pressure separator, and
hydrogen, hydrogen sulfide, carbon dioxide, and water were removed
from the treated oil.
25 [0211] Part of the hydrogenated oil after introduction into the high
pressure separator was cooled to 40°C with cooling water to be recycled
to the oils and fats obtained in (1-4), as described above. The
remaining hydrogenated oil after the recycling was introduced into a
fixed bed flow reaction apparatus (isomerization apparatus) with a
reaction tube (inner diameter: 20 mm) filled with Catalyst B (150 ml),
5 and was subjected to a hydroisomerization treatment. First, Catalyst B
was subjected to a reduction treatment under the conditions of a catalyst
layer average temperature of 320°C, a hydrogen pressure of 3 MPa, and
a hydrogen gas amount of 83 mVmin for 6 hours, and then the
hydroisomerization treatment was performed under the conditions of a
10 catalyst layer average temperature (reaction temperature) of 320°C, a
hydrogen pressure of 3 m a , a liquid hourly space velocity of 1.0 h-',
and a hydrogenloil ratio of 500 NLL.
[0212] The hydroisomerized oil after the isomerization treatment was
introduced into a rectifying column to be fractionated into a light
15 fraction having a boiling point in the range of less than 140°C, an
intermediate fiaction having an boiling point of 140 to 300°C, and a
heavy fraction having a boiling point more than 300°C. Among these,
the intermediate fraction having a boiling point of 140 to 300°C was
used as Fuel oil base 1. The hydrotreating conditions, the
20 hydroisomerization treatment conditions, and the characteristics of Fuel
oil base 1 produced are shown in Tables 5 and 6.
[0213] In Table 5, "Isomerization rate 1" in the hydroisomerized oil
after the isomerization treatment means the content of isoparaffm
having one or more branchings (% by mass), and "Isomerization rate 2"
25 means the content of isoparaffin having two or more branchings (% by
mass). Isomerization rate 1 and Isomerization rate 2 each are the
values measured by a gas chromatograph and a time of flight mass
spectrometer. "Fuel oil base yield" means the yield of the intermediate
fraction having a boiling point of 140 to 300°C based on the total
amount of the hydroisomerized oil after the isomerization treatment.
5 [0214] (Example 2)
In the above (1-3) Anaerobic fermentation step, oils and fats
were produced by the same method as that in Example 1 except that as
the nutrient, 1 g of glucose was added per 1 L culture solution instead of
diammonium hydrogenphosphate. The produced oils and fats were
10 subjected to component analysis by the same method as that in Example
1. The results of component analysis are as shown in Figure 2(b) and
Table 4.
[0215] The produced oils and fats were subjected to the hydrotreating
step by the same method as that in Example 1 to produce Fuel oil base
15 2. The hydrotreating conditions, the hydroisomerization treatment
conditions, and the characteristics of Fuel oil base 2 produced are shown
in Tables 5 and 6.
[0216] (Example 3)
In the above (1-3) Anaerobic fermentation step, oils and fats
20 were produced by the same method as that in Example 1 except that as
the nutrient, 1 g of glucose was added per 1 L culture solution and
0.1643 g (equivalent to 10 mgL) of diammonium hydrogenphosphate
((NH4)2HP04)w as added per 1 L culture solution. The produced oils
and fats were subjected to component analysis by the same method as
25 that in Example 1. The results of component analysis are as shown in
Figure 2(c) and Table 4.
[0217] The oils and fats produced were subjected to hydrotreating by
the same method as that in Example 1 to produce Fuel oil base 3. The
hydrotreating conditions, the hydroisomerization treatment conditions,
and the characteristics of Fuel oil base 3 produced are shown in Tables 5
5 and 6.
[02 1 81 (Example 4)
The oils and fats produced by the same method as that in
Example 3 were subjected to hydrotreating by the same method as that
in Example 1 except that Catalyst C was used instead of Catalyst B;
10 thus, Fuel oil base 4 was produced. The hydrotreating conditions, the
hydroisomerization treatment conditions, and the characteristics of Fuel
oil base 4 produced are shown in Tables 5 and 6.
[0219] (Comparative Example 1)
In the above (1-3) Anaerobic fermentation step, oils and fats
15 were produced by the same method as that in Example 1 except that the
nutrient was not added. The oils and fats produced were subjected to
component analysis by the same method as that in Example 1. The
results of component analysis are as shown in Figure 2(d) and Table 4.
[0220] The oils and fats produced were subjected to hydrotreating by
20 the same method as that in Example 1 to produce Fuel oil base a. The
hydrotreating conditions, the hydroisomerization treatment conditions,
and the characteristics of Fuel oil base a produced are shown in Tables 5
and 6.
[0221] (Comparative Example 2)
25 After 48 hours from the start of the culturing in the
nitrogen-deficient AY culture medium in the above (1-2)
Nitrogen-deficient culturing step, Euglena cells were recovered by
centrifugation (2500 rpm, 5 minutes, room temperature); the recovered
product was frozen, and was fieeze dried to obtain Euglena dried algal
bodies. In the obtained Euglena dried algal bodies, oils and fats were
5 extracted by the same method as that in (1-4), and the produced oils and
fats were subjected to component analysis by the same method as that in
Example 1. The results of component analysis are as shown in Figure
2 (e) and Table 4.
[0222] The oils and fats produced were subjected to hydrotreating by
10 the same method as that in Example 1 to produce Fuel oil base b. The
hydrotreating conditions, the hydroisomerization treatment conditions,
and the characteristics of Fuel oil base b produced are shown in Tables 5
and 6.
[0223] (Examples 5 to 9)
15 Fuel oil bases 1 to 4 produced in Examples each were mixed
with a commercially available petroleum aviation fuel oil base to
prepare fuel oil compositions shown in Table 7. Any one of the fuel
oil compositions satisfied aviation turbine fuel oil "Jet A, Jet A-1"
specified in ASTM D7566-11, and fuel oil compositions suitable for the
20 aviation fuel were produced. Typical characteristics of the fuel oil
composition shown in Table 7 are the values measured by the above
methods, respectively.
[0224] In Table 7, Antioxidant represents 2,6-ditert-butyl phenol,
Antistatic agent represents "STADIS450" (made by Innospec Inc.), and
25 Corrosion inhibitor represents "OCTEL DCI-4A"(made by Octel
Company Ltd.).
[0225] [Table 41
r02261 [Table 51
Reaction temnpemtwe CC) 320 320 320 320 320 320
+
Hy&ogen/oil ratio (NLJL) 500 500 500 500 500 500
8 IIy&ogen pressure (ma) 3 3 3 3 3 3 4 LHSV (h-l) 1.0 1 .O 1 .O 1.0 1.0 1.0
'3 5
$
Isomecktion rate 1 (% by
,"as)
Isomerkation rate 2 (% by
mas)
Fuel oil base (% by mass)
86
21
47
90
23
48
88
21
55
91
24
56
85
20
85
19
32 11
[0227] [Table 61
Example 1
I S ulfur v o ~ ~ l v(nIIItX %%1 rp111) .. ...