U.S. patent application number 12/295191 was filed with the patent office on 2009-07-02 for light oil composition.
Invention is credited to Yasutoshi Iguchi, Hideaki Sugano, Osamu Tamura.
Application Number | 20090165362 12/295191 |
Document ID | / |
Family ID | 38563248 |
Filed Date | 2009-07-02 |
United States Patent
Application |
20090165362 |
Kind Code |
A1 |
Iguchi; Yasutoshi ; et
al. |
July 2, 2009 |
Light Oil Composition
Abstract
The invention provides a gas oil composition wherein the molar
ratio of isoparaffins with carbon number of m and two or more
branches to isoparaffins with carbon number of m and one branch
within the range of C10-21 is 0.05-3.5, wherein m is an integer of
10-21, and the molar ratio of isoparaffins with carbon number of n
and two or more branches to isoparaffins with carbon number of n
and one branch within the range of C22-25 is 0.1-10.0, wherein n is
an integer of 22-25. The invention also provides a gas oil
composition wherein the molar ratio of isoparaffins with carbon
number of m and two or more branches to isoparaffins with carbon
number of m and one branch within the range of C10-23 is 0.05-4.0,
wherein m is an integer of 10-23, and the distillate volume at a
distillation temperature of 250.degree. C. (E250) is 15-65%.
Inventors: |
Iguchi; Yasutoshi;
(Kanagawa, JP) ; Sugano; Hideaki; (Kanagawa,
JP) ; Tamura; Osamu; (Kanagawa, JP) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Family ID: |
38563248 |
Appl. No.: |
12/295191 |
Filed: |
March 7, 2007 |
PCT Filed: |
March 7, 2007 |
PCT NO: |
PCT/JP2007/054453 |
371 Date: |
September 29, 2008 |
Current U.S.
Class: |
44/300 |
Current CPC
Class: |
C10L 1/08 20130101 |
Class at
Publication: |
44/300 |
International
Class: |
C10L 1/08 20060101
C10L001/08 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 30, 2006 |
JP |
2006-093975 |
Mar 31, 2006 |
JP |
2006-097409 |
Claims
1. A gas oil composition wherein the molar ratio of isoparaffins
with carbon number of m and two or more branches to isoparaffins
with carbon number of m and one branch within the range of C10-21
is 0.05-3.5, wherein m is an integer of 10-21, and the molar ratio
of isoparaffins with carbon number of n and two or more branches to
isoparaffins with carbon number of n and one branch within the
range of C22-25 is 0.1-10.0, wherein n is an integer of 22-25.
2. A gas oil composition according to claim 1, wherein the cloud
point is no higher than 0.degree. C. and the pour point is no
higher than -7.5.degree. C.
3. A gas oil composition according to claim 1, wherein the cetane
number is at least 65, the sulfur content is no greater than 10 ppm
by mass, the aromatic content is no greater than 1% by mass, the
naphthene content is no greater than 5% by mass and the cold filter
plugging point is no higher than -5.degree. C.
4. A gas oil composition wherein the molar ratio of isoparaffins
with carbon number of m and two or more branches to isoparaffins
with carbon number of m and one branch within the range of C10-23
is 0.05-4.0, wherein m is an integer of 10-23, and the distillate
volume at a distillation temperature of 250.degree. C., represented
by E250, is 15-65%.
5. A gas oil composition according to claim 4, wherein the cetane
number is at least 65, the sulfur content is no greater than 10 ppm
by mass, the aromatic content is no greater than 1% by mass, the
naphthene content is no greater than 5% by mass and the cold filter
plugging point is no higher than -5.degree. C.
Description
TECHNICAL FIELD
[0001] The present invention relates to gas oil compositions.
BACKGROUND ART
[0002] Conventionally known gas oil stocks include those
manufactured by hydrorefining treatment or hydrodesulfurization
treatment of straight-run gas oil obtained from atmospheric
distillation of crude oil and straight-run kerosene obtained from
atmospheric distillation of crude oil. Such gas oil stocks contain
additives such as cetane number improvers and detergents, which are
used as necessary.
[0003] Incidentally, purification of diesel engine exhaust gas has
been a goal in recent years from the viewpoint of improving the
atmospheric environment and reducing environmental load. It has
been attempted to achieve this goal by developing gas oil stocks
that can reduce contaminants in diesel exhaust gas. For example,
Patent document 1 teaches that diesel particulate emission can be
reduced by using a compression ignition engine fuel wherein the
sulfur and aromatic compound contents and the ratio of isoparaffins
and normal paraffins satisfy specific conditions.
[Patent document 1] Japanese Patent Application Laid-Open No.
2005-529213
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0004] Even such conventional gas oils, however, cannot be
considered to have sufficiently practical characteristics.
[0005] In terms of fuel efficiency performance, for example, the
ignitability tends to be reduced especially during winter season or
in cold districts. In the case of conventional gas oils, the cold
flow properties tend to be inadequate, and the aforementioned low
ignitability is often accompanied by reduction in the running
performance including the cold startability.
[0006] Methods for improving the ignition point and cold flow
properties may result in a lighter gas oil. Lightening of gas oil
is also effective from the standpoint of improving the durability
of rubber members. However, simple lightening of a gas oil can
impair the essential quality of the oil as a diesel fuel, including
the fuel efficiency and output for engine performance.
[0007] It is an object of the present invention, which has been
accomplished in light of the circumstances described above, to
provide a gas oil composition with excellent ignitability and cold
flow properties, which can be suitably used during winter season
and in cold districts. It is another object of the invention to
provide a gas oil composition which maintains adequate essential
quality as a diesel fuel while exhibiting improved ignitability and
cold flow properties.
Means for Solving the Problems
[0008] With the aim of achieving the objects stated above, the
present inventors first analyzed gas oil compositions using Gas
Chromatography with Time of Flight Mass Spectrometry (hereinafter
abbreviated as GC-TOFMS), and examined the effects of the
compositions on ignitability and cold flow properties. As a result
it was found that the ignitability and cold flow properties of a
gas oil composition can be drastically improved by establishing a
specific condition for the molar ratio of isoparaffins with two or
more branches to isoparaffins with only one branch, within
specified ranges of carbon numbers, and the invention has been
completed upon this finding.
[0009] Specifically, the invention provides a gas oil composition
characterized in that the molar ratio of isoparaffins with carbon
number of m and two or more branches to isoparaffins with carbon
number of m and one branch within the range of C10-21 is 0.05-3.5,
wherein m is an integer of 10-21, and the molar ratio of
isoparaffins with carbon number of n and two or more branches to
isoparaffins with carbon number of n and one branch within the
range of C22-25 is 0.1-10.0, wherein n is an integer of 22-25
(hereinafter referred to as "first gas oil composition").
[0010] By thus ensuring that the aforementioned specific conditions
are satisfied for the molar ratio of isoparaffins with two or more
branches to isoparaffins with only one branch that have the same
carbon number within the respective ranges of C10-21 and C22-25, it
is possible to drastically improve both the ignitability and cold
flow properties, as a result producing a gas oil composition that
can be satisfactorily used during winter season and in cold
districts.
[0011] The molar ratio of isoparaffins with two or more branches to
isoparaffins with only one branch for each range of carbon numbers
can be determined using GC-TOFMS, as mentioned above. In GC-TOFMS,
first the constituent components of the sample are separated by gas
chromatography, and the separated components are ionized. Next,
mass separation of the ions is accomplished, utilizing the fact
that the flight speed when applying a fixed acceleration voltage to
an ion differs depending on the ion mass, and mass spectra are
obtained based on the differences in arrival times to the ion
detector. The ionization method in GC-TOFMS is preferably FI
ionization, since this can inhibit production of fragment ions and
further improve measurement precision for the molar ratio of
isoparaffins with two or more branches to isoparaffins with only
one branch. The measuring apparatus and measuring conditions
according to the invention are as follows.
(GC zone)
Apparatus: HP6890 Series GC System & Injector by HEWLETT
PACKARD
[0012] Column: Agilent HP-5 (30 mB 0.32 mm.phi., 0.25 .mu.m-film)
Carrier gas: He, 1.4 mL/min (constant flow rate) Inlet temperature:
320.degree. C. Injection mode: split (split ratio=1:100) Oven
temperature: Holding at 50.degree. C. for 5 minutes, temperature
increase at 5.degree. C./min, holding at 320.degree. C. for 6
minutes. Injection volume: 1 .mu.L
(TOFMS Zone)
Apparatus: JMS-T100GC by JEOL Corp.
[0013] Counter electrode voltage: 10.0 kV Ionization method:
FI+(field ionization) GC interface temperature: 250.degree. C.
Measuring mass range: 35-500
[0014] By calculating the ratio between the total intensity of
isoparaffins with only one branch and the total intensity of
isoparaffins with two or more branches for each component having
the same carbon number, based on the aforementioned measurement
data, it is possible to obtain the molar ratio of isoparaffins with
two or more branches to isoparaffins with only one branch, for each
carbon number. The molar ratios may also be directly determined
from the mass spectra, but alternatively a graph showing the
correlation between retention time and intensity in gas
chromatography for each component having the same carbon number may
be drawn based on the mass spectrum data, and the molar ratio
determined as the ratio of peak areas for the components in the
graph.
[0015] FIG. 1 is a graph showing an example of correlation between
retention time and intensity in gas chromatography for components
having the same carbon number. In FIG. 1, the peaks for regions A,
B and C are the peaks corresponding to normal paraffins,
isoparaffins with only one branch, and isoparaffins with two or
more branches, respectively. The molar ratio of isoparaffins with
two or more branches to isoparaffins with only one branch as
specified according to the invention is calculated as the ratio
(S.sub.C/S.sub.B) which is a ratio of the peak area S.sub.C of
region C to the peak area S.sub.B of region B.
[0016] Conventional development of gas oil has dealt merely with
the ratio of normal paraffins and isoparaffins as described in
Patent document 1 cited above, whereas the composition is almost
never examined in terms of the number of branches in the
isoparaffins. Considering the technical level of the prior art, the
first gas oil composition described above has been accomplished for
the first time based on the knowledge of the present inventors that
the molar ratio of isoparaffins with two or more branches to
isoparaffins with only one branch is suitable as an index of the
ignitability and cold flow properties of the gas oil, and that
GC-TOFMS is useful as a method of measuring the molar ratio, and
moreover, the aforementioned effect of the invention may be said to
be a highly unexpected effect.
[0017] The first gas oil composition preferably has a cloud point
of no higher than 0.degree. C. and a pour point of no higher than
-7.5.degree. C.
[0018] The first gas oil composition also preferably has a cetane
number of 65 or higher, a sulfur content of no greater than 10 ppm
by mass, an aromatic content of no greater than 1% by mass, a
naphthene content of no greater than 5% by mass and a cold filter
plugging point of no higher than -5.degree. C.
[0019] The invention further provides a gas oil composition
characterized in that the molar ratio of isoparaffins with carbon
number of m and two or more branches to isoparaffins with carbon
number of m and one branch within the range of C10-23 (m is an
integer of 10-23) is 0.05-4.0, and the distillate volume at a
distillation temperature of 250.degree. C. (E250) is 15-65%
(hereinafter referred to as "second gas oil composition").
[0020] By thus ensuring that the aforementioned specific conditions
are satisfied for both the molar ratio of isoparaffins with two or
more branches to isoparaffins with only one branch that have the
same carbon number within the range of C10-23, and for E250, it is
possible to realize a gas oil composition that adequately maintains
the essential quality as a diesel fuel while exhibiting improved
ignitability and cold flow properties. The aforementioned second
gas oil composition having such excellent properties is
particularly suitable as a summer season diesel fuel.
[0021] The method of measuring the molar ratio of isoparaffins with
two or more branches to isoparaffins with only one branch for each
carbon number is the same as for the first gas oil composition
described above, and will not be explained again here.
[0022] The term "E250" according to the invention means the
distillate volume at a distillation temperature of 250.degree. C.,
calculated from a distillation curve obtained by the method of JIS
K 2254, "Petroleum Products-Distillation Test Methods-Ordinary
Pressure Method".
[0023] The second gas oil composition preferably has a cetane
number of 65 or higher, a sulfur content of no greater than 10 ppm
by mass, an aromatic content of no greater than 1% by mass, a
naphthene content of no greater than 5% by mass and a cold filter
plugging point of no higher than -5.degree. C.
EFFECT OF THE INVENTION
[0024] According to the invention there is provided a gas oil
composition with excellent ignitability and cold flow properties,
which is suitable for use during the winter season and in cold
districts. According to the invention there is further provided a
gas oil composition which maintains adequate essential quality as a
diesel fuel while exhibiting improved ignitability and cold flow
properties.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a graph obtained by GC-TOFMS, showing an example
of correlation between retention time and intensity in gas
chromatography for components having the same carbon number.
BEST MODE FOR CARRYING OUT THE INVENTION
[0026] Preferred embodiments of the invention will now be described
in detail.
First Embodiment
[0027] The gas oil composition according to the first embodiment of
the invention is characterized by satisfying both of the following
conditions (A-1) and (B-1).
(A-1) The molar ratio of isoparaffins with carbon number of m and
two or more branches to isoparaffins with carbon number of m and
one branch within the range of C10C-21 is 0.05-3.5, wherein m is an
integer of 10-21. (B-1) The molar ratio of isoparaffins with carbon
number of n and two or more branches to isoparaffins with carbon
number n and one branch within the range of C22-25 is 0.1-10.0,
wherein m is an integer of 22-25.
[0028] As regards condition (A-1), the molar ratio of isoparaffins
with carbon number of m and two or more branches to isoparaffins
with carbon number of m and one branch within the range of C10-21
must be 0.05-3.5 as mentioned above, but it is preferably 0.1-3.2,
more preferably 0.15-2.8 and even more preferably 0.2-2.5, wherein
m is an integer of 10-21. A molar ratio of less than 0.05 will
lower the volume heat release, thereby reducing the fuel efficiency
per volume. A molar ratio of greater than 3.5 will lower the
ignitability.
[0029] As regards condition (B-1), the molar ratio of isoparaffins
with carbon number of n and two or more branches to isoparaffins
with carbon number of n and one branch within the range of C22-25
must be 0.1-10.0 as mentioned above, but it is preferably 0.3-9.0,
more preferably 0.4-8.0 and even more preferably 0.5-7.0, wherein n
is an integer of 22-25. A molar ratio of less than 0.1 will result
in insufficient cold performance for actual driving, while a molar
ratio of greater than 10.0 will increase the viscosity and prevent
suitable injection control.
[0030] The aromatic content of the gas oil composition according to
the first embodiment is not particularly restricted, but from the
standpoint of controlling production of PM and the like, it is
preferably no greater than 15% by volume, more preferably no
greater than 10% by volume, even more preferably no greater than 5%
by volume and most preferably no greater than 1% by volume based on
the total composition weight. "Aromatic content" for the purpose of
the invention means the volume percentage (% by volume) of the
aromatic content as measured according to Journal of The Japan
Petroleum Institute, JPI-5S-49-97, "Hydrocarbon Type Test
Methods-High Performance Liquid Chromatography Method", published
by The Japan Petroleum Institute.
[0031] There are no particular restrictions on the naphthene
content of the gas oil composition according to the first
embodiment, but from the standpoint of controlling production of PM
and the like, it is preferably no greater than 50% by volume, more
preferably no greater than 30% by volume, even more preferably no
greater than 15% by volume and most preferably no greater than 10%
by volume based on the total composition weight. "Naphthene
content" for the purpose of the invention means the weight
percentage of the naphthene content as measured according to ASTM
D2425, "Standard Test Method for Hydrocarbon Types in Middle
Distillates by Mass Spectrometry".
[0032] In order to satisfactorily maintain the purification
performance by an exhaust gas post-treatment device in a diesel
automobile, the sulfur content of the gas oil composition according
to the first embodiment is preferably no greater than 10 ppm by
mass, more preferably no greater than 5 ppm by mass, even more
preferably no greater than 3 ppm by mass and most preferably no
greater than 1 ppm by mass based on the total composition weight.
"Sulfur content" for the purpose of the invention means the value
measured according to JIS K 2541, "Sulfur Content Test Method".
[0033] The stock of the gas oil composition according to the first
embodiment is not particularly restricted so long as the gas oil
composition satisfies the aforementioned conditions (A-1) and
(B-1), and any from among petroleum gas oil stocks, petroleum
kerosene stocks, synthetic gas oil stocks and synthetic kerosene
stocks may be used alone, or in combinations of two or more. When
two or more stocks are used in combination, it is not necessary for
each of the stocks alone to satisfy the conditions (A-1) and (B-1),
as it is sufficient if the blended gas oil composition satisfies
the conditions (A-1) and (B-1).
[0034] As specific examples of petroleum gas oil stocks to be used
for the invention there may be mentioned straight-run gas oil
obtained from apparatuses for atmospheric distillation of crude
oil; vacuum gas oil from vacuum distillation of straight-run heavy
oil or residue oil obtained from atmospheric distillation
apparatuses; hydrorefined gas oil obtained by hydrorefining of
straight-run gas oil or vacuum gas oil; hydrodesulfurized gas oil
obtained by hydrodesulfurization of straight-run gas oil or vacuum
gas oil in one or more stages under more severe conditions than
ordinary hydrorefining; and hydrocracked gas oil obtained by
hydrocracking of the different types of gas oil stocks mentioned
above.
[0035] As specific examples of petroleum kerosene stocks there may
be mentioned straight-run kerosene obtained from apparatuses for
atmospheric distillation of crude oil; vacuum kerosene from vacuum
distillation of straight-run heavy oil or residue oil obtained from
atmospheric distillation apparatuses; hydrorefined kerosene
obtained by hydrorefining of straight-run kerosene or vacuum
kerosene; hydrodesulfurized kerosene obtained by
hydrodesulfurization of straight-run kerosene or vacuum kerosene in
one or more stages under more severe conditions than ordinary
hydrorefining; and hydrocracked kerosene obtained by hydrocracking
of the different types of kerosene stocks mentioned above.
[0036] When a petroleum gas oil stock or petroleum kerosene stock
is used for this embodiment, the treatment conditions for
production of the petroleum stocks may be selected as appropriate.
The hydrogen partial pressure for hydrodesulfurization, for
example, is preferably at least 1 MPa, more preferably at least 3
MPa and most preferably at least 5 MPa. There is no particular
restriction on the upper limit for the hydrogen partial pressure,
but it is preferably no greater than 10 MPa from the viewpoint of
pressure durability of the reactor. The reaction temperature for
hydrodesulfurization is preferably 300.degree. C. or higher, more
preferably 320.degree. C. or higher and most preferably 340.degree.
C. or higher. There is no particular restriction on the upper limit
for the reaction temperature, but it is preferably no higher than
400.degree. C. from the viewpoint of heat durability of the
reactor. The liquid space velocity for hydrodesulfurization is
preferably no greater than 6 h.sup.-1, more preferably no greater
than 4 h.sup.-1 and most preferably no greater than 2 h.sup.-1.
There is no particular restriction on the lower limit for the
liquid space velocity, but it is preferably at least 0.1 h.sup.-1
from the viewpoint of drift current. The catalyst used for
hydrodesulfurization is not particularly restricted, but there may
be mentioned combinations of 2-3 different metals from among Ni,
Co, Mo, W, Pd and Pt. Specifically, Co--Mo, Ni--Mo, Ni--Co--Mo and
Ni--W catalysts are preferred, among which Co--Mo and Ni--Mo
catalysts are more preferred from the standpoint of general
versatility.
[0037] The term "synthetic gas oil stock" refers to a gas oil stock
obtained by chemical synthesis using natural gas, asphalt or coal
as the starting material. Chemical synthesis methods include
indirect liquefaction and direct liquefaction, and Fischer-Tropsch
synthesis may be mentioned as a typical synthesis method; however,
the synthetic gas oil stock used for the invention is not limited
to one produced by these methods. Most synthetic gas oil stocks are
composed mainly of saturated hydrocarbons, and specifically they
are composed of normal paraffins, isoparaffins and naphthenes. In
other words, synthetic gas oil stocks generally contain almost no
aromatic components. Thus, a synthetic gas oil stock is preferably
used when the intent is to reduce the aromatic content of the gas
oil composition.
[0038] The term "synthetic kerosene stock" refers to a kerosene
stock obtained by chemical synthesis using natural gas, asphalt or
coal as the starting material. Chemical synthesis methods include
indirect liquefaction and direct liquefaction, and Fischer-Tropsch
synthesis may be mentioned as a typical synthesis method; however,
the synthetic kerosene stock used for the invention is not limited
to one produced by these methods. Most synthetic kerosene stocks
are composed mainly of saturated hydrocarbons, and specifically
they are composed of normal paraffins, isoparaffins and naphthenes.
In other words, synthetic kerosene stocks generally contain almost
no aromatic components. Thus, a synthetic kerosene stock is
preferably used when the intent is to reduce the aromatic content
of the gas oil composition.
[0039] A gas oil composition according to the first embodiment may
contain one or more of the petroleum stocks and/or synthetic stocks
mentioned above, but it preferably contains a synthetic gas oil
stock and/or a synthetic kerosene stock as essential components
from the viewpoint of reducing the sulfur and aromatic contents
that increase the environmental load. The total of the synthetic
gas oil stock and/or synthetic kerosene stock contents is
preferably at least 20% by volume, more preferably at least 30% by
volume, even more preferably at least 40% by volume and most
preferably at least 50% by volume, based on the total weight of the
composition.
[0040] The gas oil composition of the first embodiment may be
composed only of the aforementioned gas oil stock and/or kerosene
stock, but if necessary it may also contain a cold flow improver.
As cold flow improvers there may be mentioned, specifically, cold
flow improvers including linear compounds such as
ethylene-unsaturated ester copolymers, typically ethylene-vinyl
acetate copolymer, or alkenylsuccinic acid amides, polyethylene
glycol dibehenic acid ester and the like, and tandem polymers
composed of alkyl fumarate or alkyl itaconate-unsaturated ester
copolymers, or cold flow improvers containing polar nitrogen
compounds composed of reaction products of acids such as phthalic
acid, succinic acid, ethylenediaminetetraacetic acid or
nitriloacetic acid or their acid anhydrides with
hydrocarbyl-substituted amines or the like, and any of these
compounds may be used alone or in combinations of two or more.
Among these there are preferred ethylene-vinyl acetate copolymer
additives and cold flow improvers containing polar nitrogen
compounds from the viewpoint of general versatility, while more
preferred are cold flow improvers containing polar nitrogen
compounds, from the viewpoint of promoting refining of the wax
crystals and preventing flocculated sedimentation of the wax.
[0041] The content of the cold flow improver is preferably 50-500
mg/L and more preferably 100-300 mg/L based on the total weight of
the composition. If the cold flow improver content is below the
lower limit, the effect of addition toward improving the cold flow
property will tend to be insufficient. A cold flow improver content
exceeding the upper limit generally will not provide any further
improving effect on the cold flow property commensurate with the
increased content.
[0042] The gas oil composition of the first embodiment may further
contain a lubricity improver. As lubricity improvers there may be
used one or more esteric, carboxylic, alcoholic, phenolic,
amine-based or other types of lubricity improvers. Preferred among
these from the viewpoint of general versatility are esteric and
carboxylic lubricity improvers. An esteric lubricity improver is
preferred from the viewpoint of avoiding saturation of the effect
of addition with respect to the addition concentration and further
lowering the HFRR WS1.4 value, while a carboxylic lubricity
improver is preferred from the viewpoint of high initial
responsiveness of the effect of addition with respect to the
addition concentration, allowing the lubricity improver to be
reduced in amount.
[0043] As examples of esteric lubricity improvers there may be
mentioned glycerin carboxylic acid esters, and specifically
glycerin esters of linoleic acid, oleic acid, salicylic acid,
palmitic acid, myristic acid and hexadecenoic acid, any one or more
of which may be used as appropriate.
[0044] The lubricity improver content is preferably 25-500 mg/L,
more preferably 25-300 mg/L and even more preferably 25-200 mg/L
based on the total weight of the composition. If the lubricity
improver content is below the lower limit, the effect of addition
toward improving the lubricity will tend to be insufficient. A
lubricity improver content exceeding the upper limit generally will
not provide any further improving effect on the cold flow property
commensurate with the increased content.
[0045] The gas oil composition of the first embodiment may also
contain other additives in addition to the aforementioned cold flow
improver or lubricity improver. As such additives there may be
mentioned detergents such as alkenylsuccinic acid derivatives and
carboxylic acid amine salts, phenolic, amine-based and other types
of antioxidants, metal inactivating agents such as salicylidene
derivatives, deicing agents such as polyglycol ethers, corrosion
inhibitors such as aliphatic amines and alkenylsuccinic acid
esters, antistatic agents such as anionic, cationic and amphoteric
surfactants, coloring agents such as azo dyes, and silicon-based
and other types of antifoaming agents. Such other additives may be
used alone or in combinations of two or more. The amounts of
addition may be selected as appropriate, but the total amount of
such additives is preferably no greater than, for example, 0.5% by
mass and more preferably no greater than 0.2% by mass with respect
to the gas oil composition. The total amount of addition referred
to here is the amount of additives added as active components.
[0046] The gas oil composition of the first embodiment also
preferably satisfies the following conditions in addition to the
aforementioned conditions (A-1) and (B-1), from the viewpoint of
further improving performance.
[0047] The cloud point of the gas oil composition of the first
embodiment is preferably no higher than 0.degree. C., more
preferably no higher than -2.degree. C., even more preferably no
higher than -5.degree. C. and most preferably no higher than
-8.degree. C. A cloud point of 0.degree. C. or below will tend to
facilitate dissolution of wax that has adhered onto the filter of
the fuel injector of a diesel automobile. The "cloud point"
according to the invention means the cloud point measured based on
JIS K 2269, "Crude Oil and Petroleum Product Pour Point and
Petroleum Product Cloud Point Test Methods".
[0048] The slow-cooling cloud point of the gas oil composition of
the first embodiment is preferably no higher than 0.degree. C.,
more preferably no higher than -2.degree. C., even more preferably
no higher than -5.degree. C. and most preferably no higher than
-8.degree. C. A slow-cooling cloud point of 0.degree. C. or below
will tend to facilitate dissolution of wax that has adhered onto
the filter of the fuel injector of a diesel automobile. The
"slow-cooling cloud point" according to the invention means the
value measured in the manner described below. Specifically, a
sample is placed in a sample container with an aluminum bottom
surface to a thickness of 1.5 mm, and light is irradiated from a
height of 3 mm from the bottom of the container. It is then slowly
cooled at a rate of 0.5.degree. C./min from a temperature at least
10.degree. C. higher than the aforementioned cloud point, and the
temperature at which the reflected light quantity is no more than
7/8 of the irradiated light (the slow-cooling cloud point) is
detected in units of 0.1.degree. C.
[0049] The pour point of the gas oil composition of the first
embodiment is preferably no higher than -7.5.degree. C., more
preferably no higher than -10.degree. C., even more preferably no
higher than -15.degree. C. and most preferably no higher than
-20.degree. C., from the viewpoint of guaranteeing fluidity in the
fuel line in a diesel automobile. The "pour point" according to the
invention means the pour point measured based on JIS K 2269, "Crude
Oil and Petroleum Product Pour Point and Petroleum Product Cloud
Point Test Methods".
[0050] From the viewpoint of ignitability, the cetane index of the
gas oil composition of the first embodiment is preferably at least
65, more preferably at least 70, even more preferably at least 73
and most preferably at least 75.
[0051] From the viewpoint of ignitability, the cetane number of the
gas oil composition of the first embodiment is preferably at least
65, more preferably at least 70, even more preferably at least 73
and most preferably at least 75.
[0052] The "cetane index" and "cetane number" according to the
invention are the values measured according to JIS K 2280,
"Petroleum Products-Fuel Oils-Octane Number and Cetane Number Test
Methods and Cetane Index Calculation Method".
[0053] The cold filter plugging point of the gas oil composition of
the first embodiment is preferably no higher than -5.degree. C.,
more preferably no higher than -6.degree. C., even more preferably
no higher than -7.degree. C. and most preferably no higher than
-8.degree. C., since this will help prevent clogging of the filter
installed in the fuel injector of a diesel automobile. The "cold
filter plugging point" according to the invention is the value
measured according to JIS K 2288, "Petroleum Products-Gas Oils-Cold
filter plugging point Test Methods".
[0054] The kinematic viscosity at 30.degree. C. of the gas oil
composition of the first embodiment is preferably at least 1.7
mm.sup.2/s, more preferably at least 2.0 mm.sup.2/s, even more
preferably at least 2.3 mm.sup.2/s and most preferably at least 2.5
mm.sup.2/s, and preferably no greater than 5.0 mm.sup.2/s, more
preferably no greater than 4.7 mm.sup.2/s, even more preferably no
greater than 4.5 mm.sup.2/s and most preferably no greater than 4.3
mm.sup.2/s. A kinematic viscosity at 30.degree. C. which is below
the aforementioned lower limit may lead to start-up failure or
unstable rotation of the engine during idling, when using the oil
in a diesel automobile at a relatively high temperature. On the
other hand, a kinematic viscosity at 30.degree. C. which is above
the aforementioned upper limit will tend to increase the volume of
black smoke in the exhaust gas. The "kinematic viscosity at
30.degree. C." according to the invention is the value measured
based on JIS K 2283, "Crude Oil and Petroleum Products-Kinematic
viscosity Test Methods and Viscosity Index Calculation Method".
[0055] The flash point of the gas oil composition of the first
embodiment is preferably 45.degree. C. or higher, more preferably
50.degree. C. or higher, even more preferably 53.degree. C. or
higher, and most preferably 55.degree. C. or higher, from the
standpoint of safety during handling. The "flash point" according
to the invention is the value measured based on JIS K 2265, "Crude
Oil and Petroleum Products-Flash Point Test Methods".
[0056] In regard to the distillation properties of the gas oil
composition of the first embodiment, the initial boiling point
(hereinafter, "IBP") is preferably 140.degree. C. or higher, more
preferably 145.degree. C. or higher, even more preferably
150.degree. C. or higher and most preferably 155.degree. C. or
higher, and preferably no higher than 195.degree. C., more
preferably no higher than 190.degree. C., even more preferably no
higher than 185.degree. C. and most preferably no higher than
180.degree. C. If the IBP is below the aforementioned lower limit,
the light fraction will partially gasify and the unburned
hydrocarbon content of the exhaust gas will tend to increase with a
wider misting range in the engine of a diesel automobile, thus
tending to result in a reduced hot startability and lower
rotational stability of the engine during idling. On the other
hand, if the IBP is above the aforementioned upper limit, the cold
startability and running performance in a diesel automobile will
tend to be reduced.
[0057] The 10% distillation temperature (hereinafter abbreviated as
"T10") of the gas oil composition of the first embodiment is
preferably 165.degree. C. or higher, more preferably 170.degree. C.
or higher, even more preferably 175.degree. C. or higher and most
preferably 180.degree. C. or higher, and preferably no higher than
205.degree. C., more preferably no higher than 200.degree. C., even
more preferably no higher than 195.degree. C. and most preferably
no higher than 190.degree. C. If T10 is below the aforementioned
lower limit, the light fraction will partially gasify and the
unburned hydrocarbon content of the exhaust gas will tend to
increase with a wider misting range in the engine of a diesel
automobile, thus tending to result in lower hot startability and
rotational stability of the engine during idling. On the other
hand, if T10 is above the aforementioned upper limit, the cold
startability and running performance in a diesel automobile will
tend to be reduced.
[0058] The 50% distillation temperature (hereinafter abbreviated as
"T50") of the gas oil composition of the first embodiment is
preferably 200.degree. C. or higher, more preferably 205.degree. C.
or higher, even more preferably 210.degree. C. or higher and most
preferably 215.degree. C. or higher, and preferably no higher than
260.degree. C., more preferably no higher than 255.degree. C., even
more preferably no higher than 250.degree. C. and most preferably
no higher than 245.degree. C. A T50 below the aforementioned lower
limit will tend to result in a lower fuel consumption rate, engine
output, hot startability and rotational stability of the engine
during idling, when the oil is used in a diesel automobile. On the
other hand, a T50 above the aforementioned upper limit will tend to
increase the amount of particulate matter (hereinafter, "PM")
emitted from the engine in a diesel automobile.
[0059] The 90% distillation temperature (hereinafter abbreviated as
"T90") of the gas oil composition of the first embodiment is
preferably 265.degree. C. or higher, more preferably 270.degree. C.
or higher, even more preferably 275.degree. C. or higher and most
preferably 280.degree. C. or higher, and preferably no higher than
335.degree. C., more preferably no higher than 330.degree. C., even
more preferably no higher than 325.degree. C. and most preferably
no higher than 320.degree. C. A T90 below the aforementioned lower
limit will tend to lower the fuel consumption rate, hot
startability and rotational stability of the engine during idling,
when the oil is used in a diesel automobile. Also, the improving
effect on the cold filter plugging point by the cold flow property
improver will tend to be reduced when the gas oil composition
contains a cold flow property improver. On the other hand, a T90
above the aforementioned upper limit will tend to increase the
amount of PM emitted from the engine in a diesel automobile.
[0060] The end point (hereinafter abbreviated as "EP") of the gas
oil composition of the first embodiment is preferably 310.degree.
C. or higher, more preferably 315.degree. C. or higher, even more
preferably 320.degree. C. or higher and most preferably 325.degree.
C. or higher, and preferably no higher than 355.degree. C., more
preferably no higher than 350.degree. C., even more preferably no
higher than 345.degree. C. and most preferably no higher than
340.degree. C. An EP below the aforementioned lower limit will tend
to result in a lower fuel consumption rate, hot startability and
rotational stability of the engine during idling, when the oil is
used in a diesel automobile. Also, the improving effect on the cold
filter plugging point by the cold flow property improver will tend
to be reduced when the gas oil composition contains a cold flow
property improver. On the other hand, an EP above the
aforementioned upper limit will tend to increase the amount of PM
emitted from the engine in a diesel automobile.
[0061] The terms "IBP", "T10", "T50", "T90" and "EP" used according
to the invention are the values measured based on JIS K 2254,
"Petroleum Products-Distillation Test Methods-Ordinary Pressure
Method".
[0062] As regards the lubricity of the gas oil composition of the
first embodiment, the HFRR WS1.4 value is preferably no greater
than 500, more preferably no greater than 460, even more preferably
no greater than 420 and most preferably no greater than 400. If the
WS1.4 value satisfies this condition, it will be possible to
sufficiently ensure lubricity in the injection pump of a diesel
automobile. The term "HFRR WS1.4 value" according to the invention
is an index for judging the lubricity of a gas oil, and it means
the value measured based on the Japan Petroleum Institute standard
JPI-5S-50-98, "Gas Oils-Lubricity Test Method", published by The
Japan Petroleum Institute.
Second Embodiment
[0063] The gas oil composition according to the second embodiment
of the invention is characterized by satisfying both of the
following conditions (A-2) and (B-2).
(A-2) The molar ratio of isoparaffins with carbon number of m and
two or more branches to isoparaffins with carbon number of m and
one branch within the range of C10-23 (m is an integer of 10-23) is
0.05-4.0. (B-2) The distillate volume at a distillation temperature
of 250.degree. C. (E250) is 15-65%.
[0064] In regard to condition (A-2), the molar ratio of
isoparaffins with carbon number of m and two or more branches to
isoparaffins with carbon number of m and one branch within the
range of C10-23 (m is an integer of 10-23) must be 0.05-4.0 as
mentioned above, but it is preferably 0.1-3.5, more preferably
0.15-3.0 and even more preferably 0.2-2.7. A molar ratio of less
than 0.05 will lower the volume heat release, thereby reducing the
fuel efficiency per volume. A molar ratio of greater than 4.0 will
lower the ignitability.
[0065] In regard to condition (B-2), the E250 of the gas oil
composition of the second embodiment must be 15-65% as mentioned
above, but it is preferably 20-60%, more preferably 23-55% and even
more preferably 25-50%. If E250 is less than 15%, the durability
for rubber members used in diesel automobiles will be insufficient.
If E250 is greater than 60% it will not be possible to maintain the
performance including fuel consumption rate, engine output, hot
startability and rotational stability of the engine during idling,
when the oil is used in a diesel automobile.
[0066] There are no particular restrictions on the aromatic content
of the gas oil composition of the second embodiment, but from the
viewpoint of inhibiting production of PM and the like, it is
preferably no greater than 15% by volume, more preferably no
greater than 10% by volume, even more preferably no greater than 5%
by volume and most preferably no greater than 1% by volume, based
on the total weight of the composition.
[0067] There are also no particular restrictions on the naphthene
content of the gas oil composition of the second embodiment, but
from the viewpoint of inhibiting production of PM and the like, it
is preferably no greater than 50% by volume, more preferably no
greater than 30% by volume, even more preferably no greater than
15% by volume and most preferably no greater than 10% by volume,
based on the total weight of the composition.
[0068] There are, furthermore, no particular restrictions on the
sulfur content of the gas oil composition of the second embodiment,
but it is preferably no greater than 10 ppm by mass, more
preferably no greater than 5 ppm by mass, more preferably no
greater than 3 ppm by mass and most preferably no greater than 1
ppm by mass based on the total weight of the composition, since
this can satisfactorily maintain the purification performance of an
exhaust gas post-treatment device in a diesel automobile.
[0069] The stock of the gas oil composition according to the second
embodiment is not particularly restricted so long as the gas oil
composition satisfies the aforementioned conditions (A-2) and
(B-2), and any from among petroleum gas oil stocks, petroleum
kerosene stocks, synthetic gas oil stocks and synthetic kerosene
stocks may be used alone, or in combinations of two or more. When
two or more stocks are used in combination, it is not necessary for
each of the stocks alone to satisfy the conditions (A-2) and (B-2),
as it is sufficient if the blended gas oil composition satisfies
the conditions (A-2) and (B-2).
[0070] The petroleum gas oil stock, petroleum kerosene stock,
synthetic gas oil stock and synthetic kerosene stock used for the
second embodiment are the same as for the first embodiment and will
not be explained again here.
[0071] The gas oil composition of the second embodiment may contain
one or more of the aforementioned petroleum stocks and/or synthetic
stocks, but synthetic gas oil stocks and/or synthetic kerosene
stocks are preferred among them as essential components from the
viewpoint of minimizing increase in the environmental load due to
the sulfur and aromatic contents. The total content of synthetic
gas oil stocks and/or synthetic kerosene stocks is preferably at
least 20% by volume, more preferably at least 30% by volume, even
more preferably at least 40% by volume and most preferably at least
50% by volume, based on the total weight of the composition.
[0072] The gas oil composition of the second embodiment may be
composed entirely of the aforementioned gas oil stock and/or
kerosene stock, but if necessary it may further contain a cold flow
property improver. As cold flow improvers there may be used the
same cold flow improvers mentioned in the explanation of the first
embodiment. A single cold flow improver may be used, or a
combination of two or more thereof may be used. Preferred cold flow
improvers from the standpoint of general versatility are
ethylene-vinyl acetate copolymer additives and cold flow improvers
containing polar nitrogen compounds, while more preferred are cold
flow improvers containing polar nitrogen compounds, from the
viewpoint of promoting refining of the wax crystals and preventing
flocculated sedimentation of the wax.
[0073] The cold flow improver content is preferably 50-500 mg/L and
more preferably 100-300 mg/L, based on the total weight of the
composition. If the cold flow improver content is below the lower
limit, the effect of addition toward improving the cold flow
property will tend to be insufficient. A cold flow improver content
exceeding the upper limit generally will not provide any further
improving effect on the cold flow property commensurate with the
increased content.
[0074] The gas oil composition of the second embodiment may further
contain a lubricity improver. As lubricity improvers there may be
used one or more esteric, carboxylic, alcoholic, phenolic or
amine-based lubricity improvers which were mentioned as examples in
the explanation of the first embodiment. Preferred for use among
these from the standpoint of general versatility are esteric and
carboxylic lubricity improvers. An esteric lubricity improver is
preferred from the viewpoint of avoiding saturation of the effect
of addition with respect to the addition concentration and further
lowering the HFRR WS1.4 value, while a carboxylic lubricity
improver is preferred from the viewpoint of high initial
responsiveness of the effect of addition with respect to the
addition concentration, allowing the lubricity improver to be
reduced in amount.
[0075] The lubricity improver content is preferably 25-500 mg/L,
more preferably 25-300 mg/L and even more preferably 25-200 mg/L
based on the total weight of the composition. If the lubricity
improver content is below the lower limit, the effect of addition
toward improving the lubricity will tend to be insufficient. A
lubricity improver content exceeding the upper limit generally will
not provide any further improving effect on the cold flow property
commensurate with the increased content.
[0076] The gas oil composition of the second embodiment may further
contain other additives in addition to the aforementioned cold flow
improver and lubricity improver. As such additives there may be
mentioned detergents such as alkenylsuccinic acid derivatives and
carboxylic acid amine salts, phenolic, amine-based and other types
of antioxidants, metal inactivating agents such as salicylidene
derivatives, deicing agents such as polyglycol ethers, corrosion
inhibitors such as aliphatic amines and alkenylsuccinic acid
esters, antistatic agents such as anionic, cationic and amphoteric
surfactants, coloring agents such as azo dyes, and silicon-based
and other types of antifoaming agents. Such other additives may be
used alone or in combinations of two or more. The amounts of
addition may be selected as appropriate, but the total amount of
such additives is preferably no greater than, for example, 0.5% by
mass and more preferably no greater than 0.2% by mass with respect
to the gas oil composition. The total amount of addition referred
to here is the amount of additives added as active components.
[0077] The gas oil composition of the second embodiment also
preferably satisfies the following conditions in addition to the
aforementioned conditions (A-2) and (B-2), from the viewpoint of
further improving performance.
[0078] From the viewpoint of ignitability, the cetane index of the
gas oil composition of the second embodiment is preferably at least
65, more preferably at least 70, even more preferably at least 75
and most preferably at least 80.
[0079] From the viewpoint of ignitability, the cetane number of the
gas oil composition of the second embodiment is preferably at least
65, more preferably at least 70, even more preferably at least 75
and most preferably at least 80.
[0080] The cloud point of the gas oil composition of the second
embodiment is preferably no higher than 0.degree. C., more
preferably no higher than -1.degree. C., even more preferably no
higher than -2.degree. C. and most preferably no higher than
-3.degree. C. A cloud point below this upper limit will tend to
facilitate dissolution of wax that has adhered onto the filter of
the fuel injector of a diesel automobile.
[0081] The pour point of the gas oil composition of the second
embodiment is preferably no higher than -2.5.degree. C. and more
preferably no higher than -5.0.degree. C., from the viewpoint of
guaranteeing fluidity in the fuel line in a diesel automobile.
[0082] The cold filter plugging point of the gas oil composition of
the second embodiment is preferably no higher than -1.degree. C.,
more preferably no higher than -2.degree. C., even more preferably
no higher than -3.degree. C. and most preferably no higher than
-4.degree. C., since this will help prevent clogging of the filter
installed in the fuel injector of a diesel automobile.
[0083] The kinematic viscosity at 30.degree. C. of the gas oil
composition of the second embodiment is preferably at least 2.0
mm.sup.2/s, more preferably at least 2.2 mm.sup.2/s, even more
preferably at least 2.4 mm.sup.2/s and most preferably at least 2.5
mm.sup.2/s, and preferably no greater than 4.2 mm.sup.2/s, more
preferably no greater than 4.0 mm.sup.2/s, even more preferably no
greater than 3.9 mm.sup.2/s and most preferably no greater than 3.8
mm.sup.2/s. A kinematic viscosity at 30.degree. C. which is below
the aforementioned lower limit may lead to start-up failure,
unstable rotation of the engine during idling or increased load of
the fuel injection pump, when using the oil in a diesel automobile
at a relatively high temperature. On the other hand, a kinematic
viscosity at 30.degree. C. which is above the aforementioned upper
limit will tend to increase the volume of black smoke in the
exhaust gas.
[0084] The flash point of the gas oil composition of the second
embodiment is preferably 60.degree. C. or higher, more preferably
65.degree. C. or higher, even more preferably 70.degree. C. or
higher and most preferably 75.degree. C. or higher, from the
standpoint of safety during handling.
[0085] In regard to the distillation properties of the gas oil
composition of the second embodiment, the initial boiling point
(IBP) is preferably 155.degree. C. or higher, more preferably
160.degree. C. or higher, even more preferably 165.degree. C. or
higher and most preferably 170.degree. C. or higher, and preferably
no higher than 225.degree. C., more preferably no higher than
220.degree. C., even more preferably no higher than 215.degree. C.
and most preferably no higher than 210.degree. C. If the IBP is
below the aforementioned lower limit, the light fraction will
partially gasify and the unburned hydrocarbon content of the
exhaust gas will tend to increase with a wider misting range in the
engine of a diesel automobile, thus tending to result in a reduced
hot startability and lower rotational stability of the engine
during idling. On the other hand, if the IBP is above the
aforementioned upper limit, the cold startability and running
performance in a diesel automobile will tend to be reduced.
[0086] The 10% distillation temperature (hereinafter abbreviated as
"T10") of the gas oil composition of the second embodiment is
preferably 175.degree. C. or higher, more preferably 180.degree. C.
or higher, even more preferably 185.degree. C. or higher and most
preferably 190.degree. C. or higher, and preferably no higher than
270.degree. C., more preferably no higher than 265.degree. C., even
more preferably no higher than 260.degree. C. and most preferably
no higher than 255.degree. C. If T10 is below the aforementioned
lower limit, the light fraction will partially gasify and the
unburned hydrocarbon content of the exhaust gas will tend to
increase with a wider misting range in the engine of a diesel
automobile, thus tending to result in reduction in the hot
startability and rotational stability of the engine during idling.
On the other hand, if T10 is above the aforementioned upper limit,
the cold startability and running performance in a diesel
automobile will tend to be reduced.
[0087] The 50% distillation temperature (hereinafter abbreviated as
"T50") of the gas oil composition of the second embodiment is
preferably 230.degree. C. or higher, more preferably 235.degree. C.
or higher, even more preferably 240.degree. C. or higher and most
preferably 245.degree. C. or higher, and preferably no higher than
300.degree. C., more preferably no higher than 295.degree. C., even
more preferably no higher than 290.degree. C. and most preferably
no higher than 285.degree. C. A T50 below the aforementioned lower
limit will tend to result in a lower fuel consumption rate, engine
output, hot startability and rotational stability of the engine
during idling, when the oil is used in a diesel automobile. On the
other hand, a T50 above the aforementioned upper limit will tend to
increase the amount of particulate matter (PM) emitted from the
engine in a diesel automobile.
[0088] The 90% distillation temperature (hereinafter abbreviated as
"T90") of the gas oil composition of the second embodiment is
preferably 285.degree. C. or higher, more preferably 290.degree. C.
or higher, even more preferably 295.degree. C. or higher and most
preferably 300.degree. C. or higher, and preferably no higher than
335.degree. C., more preferably no higher than 330.degree. C., even
more preferably no higher than 325.degree. C. and most preferably
no higher than 320.degree. C. A T90 below the aforementioned lower
limit will tend to lower the fuel consumption rate, hot
startability and rotational stability of the engine during idling,
when the oil is used in a diesel automobile. Also, the improving
effect on the cold filter plugging point by the cold flow improver
will tend to be reduced when the gas oil composition contains a
cold flow improver. On the other hand, a T90 above the
aforementioned upper limit will tend to increase the amount of PM
emitted from the engine in a diesel automobile.
[0089] The end point (EP) of the gas oil composition of the second
embodiment is preferably 305.degree. C. or higher, more preferably
310.degree. C. or higher, even more preferably 315.degree. C. or
higher and most preferably 320.degree. C. or higher, and preferably
no higher than 355.degree. C., more preferably no higher than
350.degree. C., even more preferably no higher than 345.degree. C.
and most preferably no higher than 340.degree. C. An EP below the
aforementioned lower limit will tend to result in a lower fuel
consumption rate, hot startability and rotational stability of the
engine during idling, when the oil is used in a diesel automobile.
Also, the improving effect on the cold filter plugging point by the
cold flow improver will tend to be reduced when the gas oil
composition contains a cold flow improver. On the other hand, an EP
above the aforementioned upper limit will tend to increase the
amount of PM emitted from the engine in a diesel automobile.
[0090] As regards the lubricity of the gas oil composition of the
second embodiment, the HFRR WS1.4 value is preferably no greater
than 500, more preferably no greater than 460, even more preferably
no greater than 420, and most preferably no greater than 400. If
the WS1.4 value satisfies this condition, it will be possible to
ensure sufficient lubricity in the injection pump of a diesel
automobile.
EXAMPLES
[0091] The present invention will now be explained in greater
detail based on examples and comparative examples, with the
understanding that these examples are in no way limitative on the
invention.
Examples 1-2, Comparative Examples 1-3
[0092] For Examples 1-2 and Comparative Examples 1-3, gas oil
compositions were prepared having the compositions and properties
listed in Table 1. The gas oil compositions of Examples 1 and 2
were fuels obtained by hydrotreatment of wax and middle fractions
obtained from natural gas by Fischer-Tropsch reaction. The gas oil
composition of Comparative Example 1 was a fuel obtained by
hydrotreatment of a wax and middle fraction obtained from natural
gas by Fischer-Tropsch reaction, but the degree of hydrotreatment
was lower than for the gas oil compositions of Examples 1 and 2.
The gas oil composition of Comparative Example 2 was a fuel
obtained by further hydrotreatment of a fuel from crude oil
produced by ordinary hydrorefining, with further treatment of
lowering sulfur content and aromatic content. The gas oil
composition of Comparative Example 3 was a fuel from crude oil
produced by ordinary hydrorefining.
[0093] The gas oil compositions of Examples 1-2 and Comparative
Examples 1-3 were subjected to the following tests.
[0094] [Ignitability Test]
[0095] In order to confirm the cold ignitability, the cold white
smoke was measured using the diesel automobile described below on a
chassis dynamometer with controllable environmental
temperature.
(Vehicle Specifications)
[0096] Engine type: Inter cooler-equipped supercharged serial
4-cylinder diesel Compression ratio: 18.5 Maximum output: 125
kW/3400 rpm Maximum torque: 350 Nm/2400 rpm Conformity to
regulations: Conformed to 1997 exhaust gas regulations
Mission: 4AT
[0097] Exhaust gas post-treatment apparatus: Oxidation catalyst
[0098] For a cold actual driving test, first the fuel system of a
diesel automobile was flashed with the evaluation fuel (each gas
oil composition) at room temperature. The flashing fuel was
extracted, the main filter was replaced with a new one, and then a
prescribed volume of evaluation fuel was loaded into the fuel tank
(1/2 the volume of the fuel tank of the test vehicle). Next, the
environmental temperature was rapidly cooled from room temperature
to 5.degree. C., and after holding at 5.degree. C. for 1 hour, it
was slowly cooled to -10.degree. C. at a cooling rate of 1.degree.
C./h, the temperature was held at -10.degree. C. for 1 hour, and a
running test was initiated. Cases in which start-up could not be
achieved even by twice repeating 10-second cranking at 30 second
intervals were recorded as unmeasurable. When start-up was
achieved, a procedure was repeated 5 times in which idling was
continued for 30 seconds and followed by full stamping of the
accelerator pedal for 5 seconds, and the volume of white smoke that
occurred was measured using a transmission measuring device. The
average value of 5 measurements was calculated for each gas oil
composition and recorded as a relative value with respect to 100 as
the average value for Comparative Example 3, to evaluate the
ignitability. The results are shown in Table 1.
[0099] [Cold Actual Driving Test]
[0100] The following two diesel automobiles A and B were used on a
chassis dynamometer with controllable environmental temperature,
for cold actual driving test.
(Vehicle a Specifications)
[0101] Maximum load: 2 t Engine type: Serial 4-cylinder diesel
Engine cylinder capacity: 4.3 L Fuel injection pump: Sequential
Conformity to regulations: Confirmed to short-term exhaust gas
regulations (base vehicle) Exhaust gas post-treatment apparatus:
PM-reduction apparatus designated by Tokyo Metropolitan Government
(conforming to category 4). Fuel used for PM-reduction apparatus:
Low-sulfur gas oil (sulfur content: .ltoreq.50 ppm by mass)
(Vehicle B Specifications)
[0102] Engine type: Inter cooler-equipped supercharged serial
4-cylinder diesel Engine cylinder capacity: 3.0 L Fuel injection
system: Common-rail system Conformity to regulations: Confirmed to
long-term exhaust gas regulations Exhaust gas post-treatment
apparatus: Oxidation catalyst
[0103] For a cold actual driving test, first the fuel system of a
diesel automobile was flashed with the evaluation fuel (each gas
oil composition) at room temperature. The flashing fuel was
extracted, the main filter was replaced with a new one, and then a
prescribed volume of evaluation fuel was loaded into the fuel tank
(1/2 the volume of the fuel tank of the test vehicle). Next, the
environmental temperature was rapidly cooled from room temperature
to 5.degree. C., and after holding at 5.degree. C. for 1 hour, it
was slowly cooled to -10.degree. C. at a cooling rate of 1.degree.
C./h, the temperature was held at -10.degree. C. for 1 hour, and a
running test was initiated. The running test consisted of "engine
start-up", "5-minute idling", "acceleration to 50 km/h" and "1 hour
running at 50 km/h", and passing or failing of the test was judged
based on the operating condition. Specifically, a judgment of
satisfactory (S) was assigned when no problems were encountered
with engine start-up, idling or acceleration, and running at 50
km/h was maintained throughout the entire running period. A
judgment of adequate (A) was assigned in cases where minor problems
were encountered but running could be continued, such as when the
engine did not start up with the first cranking, or when the
vehicle speed slowed temporarily during running but subsequently
recovered. A judgment of bad (B) was assigned in cases where
running could not be maintained, such as failure to start-up (no
start-up even after 5 repetitions of 10-second cranking at 30
second intervals), idling stall or engine stop. The results are
shown in Table 1.
TABLE-US-00001 TABLE 1 Comp. Comp. Comp. Example 1 Example 2 Ex. 1
Ex. 2 Ex. 3 Ratio of (paraffins with two or C10 0.27 0.29 0.05 2.32
0.03 more branches/paraffins with only C11 0.40 0.43 0.06 3.60 0.04
one branch) C12 0.54 0.47 0.05 3.51 0.04 (molar ratio) C13 0.77
0.76 0.07 4.01 0.27 C14 0.79 0.73 0.12 2.81 0.40 C15 0.93 0.81 0.16
3.02 0.54 C16 1.06 1.32 0.17 2.02 0.77 C17 1.05 1.24 0.17 1.02 0.78
C18 0.89 0.88 0.18 0.62 0.93 C19 1.16 0.99 0.18 0.27 1.06 C20 1.15
1.70 0.17 0.18 1.40 C21 1.40 1.01 0.59 0.06 2.34 C22 2.34 1.42 0.21
0.04 2.11 C23 2.11 1.30 0.16 0.02 1.31 C24 1.31 2.41 0.08 0.01 0.71
C25 0.71 6.63 0.07 0.01 1.16 Sulfur content (ppm by mass) <1
<1 <1 <1 4 Aromatic content (% by volume) <0.1 <0.1
<0.1 <0.1 19.9 Naphthene content (% by volume) <0.1
<0.1 <0.1 51.0 34.9 Density at 15.degree. C. (kg/m.sup.3) 771
768 771 812 828 Kinematic viscosity at 30.degree. C. (mm.sup.2/s)
2.8 2.3 2.8 3.5 3.7 Distillation 10% distillation temp. (.degree.
C.) 197.7 183.5 210.5 178.5 195.1 properties 50% distillation temp.
(.degree. C.) 260.9 248.5 282.5 261.5 260.9 90% distillation temp.
(.degree. C.) 308.4 314.0 341.5 323.0 309.1 Cetane number 79 74 80
57 56 Cetane index 85 80 84 61 59 Pour point (.degree. C.) -7.5
-25.0 -10.0 -5.0 -7.5 Cold filter plugging point (.degree. C.) -8.0
-20.0 -1.0 -6.0 -8.0 Cloud point (.degree. C.) -8.0 -19.0 1.0 -5.0
-8.0 Ignitability 83 87 90 105 100 Cold flow property Vehicle A A S
B B A Vehicle B A S B B A
Examples 3-4, Comparative Examples 4-5
[0104] For Examples 3-4 and Comparative Examples 4-5, gas oil
compositions were prepared having the compositions and properties
listed in Table 2. The gas oil compositions of Examples 3 and 4
were fuels obtained by hydrotreatment of wax and middle fractions
obtained from natural gas by Fischer-Tropsch reaction. The gas oil
composition of Comparative Example 4 was a fuel obtained by
hydrotreatment of a wax and middle fraction obtained from natural
gas by Fischer-Tropsch reaction, but the degree of hydrotreatment
was lower than for the gas oil compositions of Examples 3 and 4.
The gas oil composition of Comparative Example 5 was a fuel
obtained by further hydrotreatment of a fuel from crude oil
produced by ordinary hydrorefining, with further treatment of
lowing sulfur content and aromatic content.
[0105] The gas oil compositions of Examples 3-4 and Comparative
Examples 4-5 were subjected to the following tests.
[0106] [Ignitability Test]
[0107] In order to confirm the cold ignitability, the cold white
smoke was measured using the diesel automobile described below on a
chassis dynamometer with controllable environmental
temperature.
(Vehicle Specifications)
[0108] Engine type: Inter cooler-equipped supercharged serial
4-cylinder diesel Compression ratio: 18.5 Maximum output: 125
kW/3400 rpm Maximum torque: 350 Nm/2400 rpm Conformity to
regulations: Conformed to 1997 exhaust gas regulations
Mission: 4AT
[0109] Exhaust gas post-treatment apparatus: Oxidation catalyst
[0110] For a cold actual driving test, first the fuel system of a
diesel automobile was flashed with the evaluation fuel (each gas
oil composition) at room temperature. The flashing fuel was
extracted, the main filter was replaced with a new one, and then a
prescribed volume of evaluation fuel was loaded into the fuel tank
(1/2 the volume of the fuel tank of the test vehicle). Next, the
environmental temperature was rapidly cooled from room temperature
to 10.degree. C., and after holding at 10.degree. C. for 1 hour, it
was slowly cooled to 0.degree. C. at a cooling rate of 1.degree.
C./h, the temperature was held at 0.degree. C. for 1 hour, and a
running test was initiated. Cases in which start-up could not be
achieved even by twice repeating 10-second cranking at 30 second
intervals were recorded as unmeasurable. When start-up was
achieved, a procedure was repeated 5 times in which idling was
continued for 30 seconds and followed by full stamping of the
accelerator pedal for 5 seconds, and the volume of white smoke that
occurred was measured using a transmission measuring device. The
average value of 5 measurements was calculated for each gas oil
composition and recorded as a relative value with respect to 100 as
the average value for Comparative Example 5, to evaluate the
ignitability. The results are shown in Table 2.
[0111] [Hot Start-Up Test]
[0112] In order to evaluate the hot start-up performance for each
gas oil composition, a hot start-up test was carried out in the
following manner using the diesel engine-mounted vehicle described
below on a chassis dynamometer with controllable environmental
temperature and humidity. After supplying 15 L of test fuel to the
vehicle, the engine was started up and kept idling. The
environmental temperature was set to 25.degree. C. to stabilize the
test room temperature, and the engine was stopped upon
stabilization of the outlet temperature of the fuel injection pump
of the idling vehicle. After allowing the stopped engine to stand
for 5 minutes it was restarted, and in cases where the engine
restarted normally, the environmental temperature was raised to
30.degree. C. and then to 35.degree. C. and the previous test
procedure was repeated. For this test, a judgment of "pass" (A) was
assigned for normal starting and a judgment of "fail" (B) was
assigned for failure to start. The results are shown in Table
2.
(Vehicle Specifications)
[0113] Maximum load: 4 t Engine type: Serial 6-cylinder diesel
Engine cylinder capacity: 8.2 L Fuel injection pump: High-pressure
distributor Conformity to regulations: Conformed to long-term
exhaust gas regulations (Prefectural designations for low-polluting
vehicles) Exhaust gas post-treatment apparatus: Oxidation
catalyst
[0114] [Rubber Swelling Test]
[0115] A soak test was carried out by the following procedure to
confirm the effect on rubber members used in engine O-rings and the
like. The object of evaluation was a rubber member made of nitrile
rubber (medium nitrile rubber), wherein the center value for the
weight of bonded acrylonitrile, a constituent compound of the
rubber, was between 25% and 35% of the total, and the test sample
was heated to and kept at 100.degree. C., after which the test
rubber member was soaked therein for 70 hours, according to MIL
R6855. The change in volume of the test rubber member after 70
hours was measured, and the durability of the rubber member was
evaluated. The results are shown in Table 2. A mark of "A" in the
column "Rubber swelling test" in Table 2 indicates that the changes
in volume, hardness and tensile strength before and after the test
were within .+-.10%, a mark of "B" indicates that they were from
.+-.10% to .+-.20%, and a mark of "C" indicates that they were
.+-.20% or greater.
TABLE-US-00002 TABLE 2 Comp. Comp. Example 3 Example 4 Ex. 4 Ex. 5
Ratio of (paraffins with two or more C10 0.28 0.27 0.04 0.02
branches/paraffins with only one C11 0.45 0.40 0.08 0.03 branch)
C12 0.59 0.54 0.06 0.04 (molar ratio) C13 0.85 0.76 0.14 0.07 C14
0.90 0.63 0.13 0.13 C15 0.97 0.87 0.11 0.31 C16 1.07 1.06 0.13 0.70
C17 1.07 1.05 0.07 0.92 C18 1.10 0.89 0.13 1.07 C19 1.17 1.16 0.11
1.10 C20 1.19 1.15 0.11 1.17 C21 1.60 1.40 0.04 1.40 C22 2.66 2.34
0.05 1.06 C23 2.31 2.11 0.06 1.19 Sulfur content (ppm by mass)
<1 <1 <1 <1 Aromatic content (% by volume) <0.1
<0.1 0.1 <0.1 Naphthene content (% by volume) <0.1 <0.1
<0.1 60.0 Density at 15.degree. C. (kg/m.sup.3) 773 776 786 812
Kinematic viscosity at 30.degree. C. (mm.sup.2/s) 2.9 3.3 4.7 3.5
Distillation 10% distillation temp. (.degree. C.) 203.5 220.5 255.5
218.0 properties 50% distillation temp. (.degree. C.) 263.0 271.5
280.0 271.0 90% distillation temp. (.degree. C.) 309.5 311.0 327.5
323.0 E250 (%) 35.5 28.7 8.7 33.9 Cetane number 80 82 87 64 Cetane
index 84.3 87.1 86.3 64.6 Pour point (.degree. C.) -5.0 -5.0 2.5
-12.5 Cold filter plugging point (.degree. C.) -4.0 -4.0 -1.0 -8.0
Cloud point (.degree. C.) 0.0 -1.0 4.0 -6.0 Ignitability 93 89 87
100 Hot start-up test A A B B Rubber swelling test A A C B
* * * * *