Note: Descriptions are shown in the official language in which they were submitted.
1339~40
FLOW-IMPROVED FUEL OIL COMPOSITION
BACKGROUND OF THE INVENTION
a) Field of the Invention
This invention relates to a fuel oil composition
having a low flowability at low temperatures prepared from a
heavy distillate fuel of petroleum and a low temperature
flow improver.
b) Prior Art
As is well known, among fractions obtained by
distilling crude oil, those called as middle and heavy
fractions and having boiling points from about 150 ~C to 450
~C , respectively, are used extensively as various fuel
sources such as kerosene, gas oil, and heavy oil A.
Particularly, kerosene and heavy oil A suffer
remarkable decrease in flowability at low temperatures (or
cold flowability) in winter season and the like due to
separation of wax component contained in the oil, which
tends to cause severe problems.
For example, under cold conditions of winter
season, the wax component contained in kerosene separates
out and causes clogging or plugging of minute screen which
is incorporated in a filter for preventing impurities
provided in midway in a pipeline from a kerosene tank to an
engine in a diesel automobile, so that supply of kerosene
becomes impossible and as the result the engine stops.
Under much lower temperature conditions, kerosene as a whole
-1- *
13~9S~O
gels to lose flowability.
Separation of wax component occurs also in heavy
oil A, which is used widely for driving engines in fishing
boats, for warming greenhouses used in order to accelerate
cultivation as well as for heating buildings, resulting in
incomplete combustion which gives a serious influence to
humans and plants.
Various measures have heretofore been taken in
order to maintain sufficient flowability of fuel oil at low
temperatures.
For example, a method is known in which fuel oil
is heated with warm water or with an electric heater in
order to prevent decrease in the temperature of the fuel oil
due to decrease in the ambient temperature, and to keep the
temperature of the fuel oil at certain temperature range.
However, this method is practically disadvantageous because
it requires amelioration or reconstruction of installments
and incur additional cost for energy.
Also, it is known to dilute fuel oils with those
fractions which retain cold flowability at relatively low
temperatures, e.g., kerosene fractions. This method is not
suitable because relatively light fuel oils to which the
kerosene fractions belong are in great demand and highly
value-added.
Another conventional method for improving the cold
flowability of fuel oils is to add a cold flow improver to
the fuel oils.
The action of the cold flow improver is to give
influence upon separation-out of wax from fuel oils to
prevent the growth of wax into large-size cyrstals but
13~S~O
retain the wax in the form of minute crystals, thus
stabilizing the cold flowability.
Various synthetic chemicals have been proposed as
a cold flow improver. However, their effect vary extremely
depending on the characteristics of fuel oils to which they
are added; it is very important to grasp the
characteristics of fuel oils which can be subjected to
quality control steadily. However, this is very difficult
because there are a great variety of crude oil types very
complicated operational conditions of distilling apparatus
and other factors are involved.
In order for the cold flow improver to virtually
exhibit its effect upon addition, various considerations
have been taken on the characteristics of the fuel oils
concerned.
For example, Published Unexamined Japanese Patent
Application No. Sho-58-134188 describes improvement in the
cold flowability of a middle fraction fuel oil by adding 0.2
to 1.5 parts by weight of an ethylene copolymer and n-
paraffin having 26 to 27 carbon atoms to 100 parts by weight
of the fuel oil.
This method not only requires addition of both the
ethylene copolymer and n-paraffin, which causes complication
of installments and operation, but also involves increase in
the amont of wax separated out at low temperatures because
of paraffin, which is a principal causal substance for
aggravation of cold flowability due to separating-out of
wax, is positively added. As the result, it is often the
case that the cold flow improver does not act effectively.
In a typical utility where fuel oil is used as a
1339~0
fuel for driving a Diesel engine automobile, fuel oil is
passed in a fuel supply pipeline in the midway of which is
provided with a strainer which tends to cause early plugging
because of separation-out of wax in great amounts, resulting
in shortened wax saturation time. Therefore, this solution
involving provision of strainer is undesirable.
Published Unexamined Japanese Patent Application
No. Sho-61-58116 discloses a composition containing gas oil
of which the content of paraffin wax that separates out at a
temperature of -20~C is adjusted to a level of from 5.5 to
12 wt.% and a pour point depressant.
However, this proposal is insufficient because
even with gas oil of which the content of paraffing wax
separating out at -20~C is specifically adjusted to a range
of from 5.5 to 12 wt.%, it sometimes happens that the
addition of a pour point depressant fails to decrease CFPP
(cold filter plugging point) at all, and that decrease of
CFPP cannot be achieved until a specified pour point
depressant is added.
As described above, it has conventionally been
difficult to provide fuel oils of which cold flowability has
been improved steadily because the prior art additives are
effective only to fuel oils having specific characteristics
or because a large amount of a specific substance other than
the additive must be added in order to facilitate exhibition
of the effect of the prior art additives.
~ A -4-
6 4 0
SUMMARY OF THE INVENTION
Therefore, an object of an aspect of this invention
is to obviate the above-described defects of the prior
arts and provide a fuel oil mainly composed of medium
and/or heavy distillates of crude oil and having an
improved cold flowability.
An object of an aspect of this invention is to
optimize the amount of n-paraffin contained in the
middle and/or heavy distillates of crude oil in order to
have sufficiently exhibited the effect of a cold flow
improver.
As a result of extensive research, this invention
has been completed, which provides a fuel composition
comprising a base fuel oil composed mainly of middle
and/or heavy distillates of crude oil and containing n-
paraffin having at least 25 carbon atoms in an amount of
not smaller than 0.1 wt.% and smaller than 0.6 wt.% and
wax which separates out at a temperature by 10~C lower
than the cloud point in an amount of smaller than 4
wt.%, and a cold flow improver composed of a copolymer
of ethylene and a vinyl ester of an unsaturated
carboxylic acid, the copolymer having an ethylene
content of 60 to 80 wt.% and a number average molecular
weight of 1,000 to 5,000, in an amount of 30 to 1,500
ppm.
Another aspect of this invention is as follows:
A method for improving the cold flow properties,
measured as decreased cold filter plugging point of base
fuel oil com~ ~~ mainly of middle or heavy distillates
of crude oil, the method comprising the following steps:
(a) determining the amount of n-paraffin having at
least 25 carbon atoms and the amount of wax which
separates out at a temperature of 10~C lower than the
cloud point,
IB
1~3g~0
(b) if necessary, adjusting the amount of n-
paraffin having at least 25 carbon atoms in said base
fuel oil to an amount of not smaller than 0.1% by
weight, and smaller than 0.6% by weight, and the amount
of said wax to smaller than 4% by weight, and
(c) adding a cold flow improver composed of a
copolymer of ethylene and vinyl acetate which has an
ethylene content of 60-75% by weight and a number
average molecular weight of 1000-4000, and a molecular
weight distribution of not greater than 4.0, and
contains not more than 5 methyl terminated side çh~ i nc
per 100 main chain methylene units in addition to methyl
groups contained in the acetyl groups thereof in an
amount of 30 to 1500 ppm.
BRIEF DESCRIPTION OF DRAWINGS
Fig. 1 is a graph representing gas chromatogram of
test oil No.5 obtained by the t~çhnigue of gas
chromatographic n-paraffin analysis according to
example, with the portions calculated as n-paraffin
being shadowed with oblique lines.
Fig. 2 is a graph showing relationship between the
content of n-paraffin having at least 25 carbon atoms
contained in various test oils and decrease in the cold
5a
tB
1339~40
filter plugging point (~ CFPP) upon the addition of 500 ppm
of Additive A, i.e., a 60 wt.% xylene solution of an
ethylene-vinyl acetate copolymer having a vinyl acetate
content of 36.5 wt.% and a number average molecular weight
of 1,690.
Fig. 3 is a graph showing relationship between the
content of n-paraffin having at least 25 carbon atoms
contained in various test oils and decrease in the cold
filter plugging point (~ CFPP) upon the addition of 500 ppm
of Additive B, i.e., a 60 wt.% xylene solution of an
ethylene-vinyl acetate copolymer having a vinyl acetate
content of 16.5 wt.% and a number average molecular weight
of 2,200.
Fig. 4 is a graph showing relationship between the
content of n-paraffin having at least 25 carbon atoms
contained in various test oils and decrease in the cold
filter plugging point (~ CFPP) upon the addition of 500 ppm
of Additive C, i.e., a 60 wt.% xylene solution of an
ethylene-vinyl acetate copolymer having a vinyl acetate
content of 44.6 wt.% and a number average molecular weight
of 1,820.
DETAILED DESCRIPTION OF THE INVENTION
In this invention, the term "base fuel oil
composed mainly of middle and/or heavy distillates of crude
oil" used herein refers to distillate oils obtained by
distilling crude oil which is a mixture of a great number
of components composed mainly of hydrocarbons having a
boiling point of from about 150~C to about 450 ~C .
Examples of distillate fractions obtained from
4 0
general petroleum distilling installments include light gas
oil, heavy gas oil, or heavy gas oil hydrogenated using a
purifier such as a unifiner, or vacuum gas oil which is
obtained by vacuum distilling the distillation residue from
normal pressure distillator in a vacuum distillator and its
hydrogenated product. They can be used as a blend depending
on their application.
If necessary, the base fuel oil can be mixed with
a small amount of middle or heavy distillate oil generated
in petroleum purifiers, e.g., oils treated in catalytic
cracking apparatus, hydrogenolysis apparatus, etc. or
residual oils after dewaxing during manufacture of
lubricants.
Further, it can be mixed with a small amount of normal
pressure residual oil or vacuum residual oil or extracted
oil generated during the step of purification of lubricants,
as is generally adopted as a method for adjusting heavy oil
A.
In this invention, the amount of n-paraffin having
at least 25 carbon atoms contained in the middle and/or
heavy distillate oils of petroleum as base fuel oil can be
analyzed in a usual manner using a programmed-temperature
gas chromatography apparatus.
More particularly, a trace amount sample is
analyzed using a hydrogen flame ionizing detector with a
column packed with a filler composed of a partition agent
having a weak polarity and a porous carrier, and the content
of n-paraffin is obtained from the respective chromatograms
of the separated components.
For example, a sample oil is injected into a
133~640
column of a stain-less steal tube having a diameter of 3 mm
and a length of 4,000 mm packed with a column filler
(Silicon GE SE-30, 2%, 60/80 mesh, Uniport HP carrier)
commercially available from Wako Pure Chemicals Industries,
Ltd. and the temperature of the column is elevated starting
from 70~C to 270 ~C at a rate of 5 ~C /min., and detection is
performed by hydrogen flame ionizing method. The electric
signals detected are processed with a recorder or data
processor as output to outside. The content of n-paraffin
can be obtained by calculating n-paraffin peak.
In this invention, the content of n-paraffin
having at least 25 carbon atoms contained in the middle
and/or heavy distillate oils of petroleum as base fuel oil
is preferably not smaller than 0.1 wt.% and smaller than 0.6
wt%.
When the content of n-paraffin having at least 25
carbon atoms is smaller than 0.1 wt%, the effect of
improvement in cold filter plugging point with a cold flow
improver becomes poor. On the other hand, when it is larger
than 0.6 wt%, although sometimes addition of a very large
amount, e.g., 2,000 ppm or more, of a cold flow improver
permits improvement in cold filter plugging point, total
amount of wax which separates out increases, resulting in
that the fuel oil obtained tends to be one which cannot be
used practically.
Preferred amount of n-paraffin having at least 25
carbon atoms with which the effect of cold flow improver
added can be exhibited more efficiently is not smaller than
0.2 wt.% and smaller than 0.5 wt.%. In this range, addition
of a relatively low amount of cold flow improver enables
133964~
sufficient decrease in the cold filter plugging point.
Examples of the cold flow improver used in this
invention include those described in "Shinpan Sekiyu Seihin
Tenkazai" ed. by Toshio Sakurai, Saiwai Shobo, July 1986,
pp.192-195. More particularly, ethylene copolymers
disclosed in Japanese Patent Publication Nos. Sho-48-23165,
Sho-55-33480, and Sho-60-17399, Published Unexamined
Japanese Patent Application No. Sho-59-136391.
Examples of the ethylene copolymer include those
copolymers which contain one or more vinyl esters of
saturated fatty acids such as vinyl acetate, vinyl
propionate, vinyl butyrate, etc. as a comonomer. They may
be a low molecular weight product obtained by decomposing a
high molecular weight ethylene copolymer with oxygen,
peroxides, heat, etc.
Preferred ethylene coplymer inlcudes those
copolymers which have an ethylene content of 60 to 80 wt.%,
and a number average molecular weight in the range of from
1,000 to 5,000 measured by vapor ressure equilibrium method.
When the etylene content is below 60 wt.% or not
lower than 80 wt.%, or the number average molecular weight
is below 1,000 or not lower than 5,000, the effect of
improvement in cold filter plugging point is rather poor and
a large amount of the improver must be added, which is not
advantageous from economical viewpoint.
The ethylene copolymer may be used singly or as a
mixture of two or more of it. Although the ethylene
copolymer can be mixed with and dissolved in fuel oils as it
is, it is industrially preferred to dissolve it in a
hydrocarbon based solvent and use it as a 10 to 90 wt.%
1~39~~
solution.
Among the ethylene copolymers described above,
ethylene-vinyl acetate coplymers are particularly preferred
because they are not only readily available on industrial
scale but also are excellent in the effect of improving cold
flowability.
More preferred ethylene-vinyl acetate copolymer is
those copolymers having an ethylene content of 60 to 75
wt.%, and a number average molecular weight of 1,000 to
4,000, with molecular weight distribution being not lower
than 4.0, and containing not more than 6 methyl terminated
side chains per 100 main-chain methylene groups as well as
methyl groups contained in the acetyl group. The copolymers
exhibit further decrease in cold filter plugging point.
The molecular weight distribution is obtained from
the ratio of weight average molecular weight (Mw)/number
average molecular weight (Mn) calculated as standard
polystyrene according to gel permeation chromatography (GPC)
(cf. "Kobunshi Sokuteihou, Kouzou to Bussei" vol. 1, ed. by
Kobunshi Gakkai, Baihukan, 1973, pp.76-89).
Further, the degree of branching as used herein is
expressed as the number of methyl terminated side chains per
100 main-chain methylene groups besides methyl groups in the
acetoxy groups, and calculated from the results obtained by
nuclear magnetic resonance (IH NMR) method (cf. the method
described in "Nippon Kagaku Kai Shi", No. 1, 1980, pp.74-
78).
That is, peak ratio based on methyl group and
methylene group in proton nuclear magnetic resonance
spectrum is obtained. Separately, the vinyl acetate content
- 1 0 -
13~ 40
is obtained by saponification method and the number average
molecular weight is obtained by vapor pressure osmotic
pressure method. The degree of branching is calculated from
the peak ratio, the vinyl acetate content and the number
average molecular weight. It is to be noted that assumption
is made that both the ends of the main-chain methylene
groups are methyl groups and that all the side chains are
ethyl groups, and therefore, 2 terminal methyl groups are
deduced upon calculation.
The amount of the cold flowability improver used
in this invention is in the range of preferably 30 to 1,500
ppm, more preferably 50 to 1,000 ppm based on the weight of
the base fuel oil composed of the middle and/or heavy
distillates of petroleum.
When the amount of addition is below 30 ppm,
decrease in cold filter plugging point is hardly expectable,
while with the amount of addition above 1,500 ppm,
economical advantage as compared with the results obtained
is poor, which is undesirable.
The fuel oil composition of this invention may
contain one or more of rust preventives, antioxidants,
antistatics, cetane value improvers and anticorrosives.
EXAMPLES
Hereinafter, the fuel oil composition of this
invention will be explained concretely by way of examples.
However, this invention should not be construed as being
limited thereto.
Various analyses and measurements of test oils
were performed by the following methods.
133~fi4Q
(1) Specific density JIS K2249 (1986)
(2) Kinematic viscosity JIS K2283 (1986)
(3) Distillation test JIS K2254 (1986)
(4) Cloud point JIS K2269 (1986)
(5) Pour point JIS K2269 (1986)
(6) CFPP (cold filter plugging point):
Measured using an automated cold filter plugging
point tester (A4F2 type manufactured by Yoshida Kagaku Kikai
Co., Ltd. according to Cold Filter Plugging Point of
Distillate Fuels shown in IP-309 (1976, United Kingdom)
(7) Amount of wax separated out:
In 50 g of a test oil was dissolved 200 ppm of a
cold flowability improver (STABINOL FI-18 (registered
trademark), commercially available from SUMITOMO CHEMICAL
CO., LTD) and the solution was cooled in a 100 ml graduated
cylinder from room temperature to -5 ~C , -10 ~C , or a
temperature 10 ~C below the cloud point at a rate of 1
C /hr. Oil component other than wax separated out from the
cooled test oil was each removed under vacuum through a
filter metal fitting to which 5 ~ m membrane filter is
attached, and 50 ml of cold ethanol/ethyl ether (2/1 by
volume) was added to the residual wax component, followed by
gentle stirring and then removal of oil component under
vacuum.
Further, 50 ml of cold ethanol was added to the
residual wax component and the mixture was all intorduced
into 1lG4 glass filter to remove oily component under
vacuum. After the wax component which remained on the glass
filter was air-dried for one day and one night, the weight
of wax component was measured to obtain the amount of wax
-12--
133~640
separated out.
(8) n-Paraffin content:
The content of n-paraffin in the test oil was
obtained using GAS CHROMATOGRAPH GC-9A type and CHROMATOPACK
C-R2AX data processor, manufactured by Shimazu Seisakusho
Co., Ltd. n-Triacontane was used as an inner standard
substance for quantitative determination. Principal
operational conditions are as follows.
Column: Made of stainless steal, 3 mm in inner diameter and
4m in length
Column filler:
Silicon GE SE-30 (manufactured by Wako Pure
Chemicals Industry, Ltd.~, 2%, 60/80 mesh (Uniport
HP carrier)
Injection Temperature: 270 C
Carrier Gas: Helium
Detector: Hydrogen flame ionizing detector
Column temperature elevation rate: 5 ~C /min. (70 -~ 270 ~C)
Example 1
To Diesel gas oil samples Nos. 1 to 4 of which
characteristics are shown in Tables 1 and 2 were added 500
ppm of a cold flowability improver composed of a 50 wt.%
xylene solution of various cold flowability improving
substances, and CFPP was measured.
The results of evaluation of the effect by
temperature decrease from CFPP of the sample oil itself
(A CFPP) are shown in Table 3.
-13-
1'33~40
Table 1
_
Sample No. 1 2 3 4 _
Specific Density 0.8290 0.8340 0.8480 0.8521
(15/4~C)
Kinematic Viscosity 4.899 4.556 5.685 5.981
(30~C) cSt
Distillation Test ( C)
Initial Boiling Point191 175 244 206
10% Boiling Point 236 229 275 246
90% Boiling Point 346 342.5 327 356.5
Dry Point 368 364 338 382
Cloud Point (CP) ~C 0 -3 -6 2
Pour Point ~C -5 -7.5 -10 -10
CFPP ~C -3 -5 -8 -7
Amount of Wax
Separated Out (wt%)
-5~C 0.84 0.62 0.00 1.21
- 10~C 1.86 1.75 2.25 2.35
CP-10~C 1.86 2.65 4.63 2.95
Note: CP-10~C is a temperature 10~C below the cloud point
- l4 -
13396~Q
Table 2
_ __ _ n-Paraffin Content (wt.%)
Carbon Number
of n-ParaffinNo. 1 No. 2 No. 3 No. 4
0.04 0.04 0.03 0.00
11 0.63 0.58 0.12 0.00
12 0.68 0.68 0.15 0.10
13 0.88 0.92 0.40 0.34
14 1.51 1.42 0.82 1.59
1.94 2.17 1.71 1.20
16 2.30 2.59 3.13 1.73
17 3.40 2.90 4.98 1.56
18 2.42 2.57 3.52 1.55
19 1.54 1.63 2.19 1.46
1.23 1.23 1.51 1.30
21 0.81 0.77 0.75 0.84
22 0.61 0.54 0.42 0.73
23 0.41 0.36 0.18 0.46
24 0.27 0.22 0.10 0.38
0.16 0.15 0.02 0.27
26 0.10 0.08 0.02 0.16
27 0.05 0.03 0.00 0.11
28 0.02 0.01 0.00 0.06
29 0.00 0.00 0.00 0.02
Total of C25-~0.33 0.27 0.04 0.62
Note: "Total of C25~ " indicates total of n-paraffin having
at least 25 carbon atoms.
133~6~Q
Table 3
CFPP (~C)
Sample
Run No. Cold Flow Improver No.1 No.2 No.3 No.4
1 EVA Copolymer 12 7 0 0
(VA 34 wt.%, Mn 1630)
2 EVA Copolymer 10 5 0 0
(VA 28 wt.%, Mn 2050)
3 EVA Copolymer 8 4 0 0
(VA 29 wt.%, Mn 2100)
4 EVA Copolymer 4 0 0 0
(VA 18 wt.%, Mn 2300)
Table 3 (continued)
Number of Methyl
M.W.Terminated Side Chain
Run No. Distribution(groups/100_methylene groups)
_ .
1 2.2 3.6
2 2.8 7.2
3 4.4 3.8
4 2.4 5.9
Notes: "VA" stands for vinyl acetate, and "Mn" indicates number
average molecular weight.
- l6-
1~39640
Example 2
Diesel gas oil samples Nos. 5 and 9 shown in Tables 4 and 5
were mixed with each other at a mixing ratio of 75/25 (Sample No. 6),
50/50 (Sample No. 7), or 25/75 (Sample No. 8), each by volume. The
characteristics of mixed test oils are also shown in Tables 4 and 5.
To these sample oils were added 300 ppm or 500 ppm of
Additive A composed of a 60 wt.% xylene solution of an ethylene-vinyl
acetate copolymer having a viny acetate content of 36.5 wt.%, a number
average molecular weight of 1,690, and a number of methyl terminated
side chains of 3.8 groups/100 methylene groups, and CFPP of each
mixture was measure.
The results of evaluation of the effect by temperature
decrease from CFPP of the sample oil itself (A CFPP) are shown in
Table 6 and Fig. 2.
- 17 -
1339~;~0
Table 4
Sample No. 5 6 7 8 9
Specific Density 0.8405 0.8405 0.84100.8410 0.8410
~ (15/4~C)
Kinematic Viscosity 4.582 4.542 4.517 4.430 4.387
(30~C) cSt
Distillation Test ( C)
Initial Boiling Point 201.5 200 207 214 215
10% Boiling Point 238 240 239 240 242
90% Boiling Point 342 341 340.5 335 330
Dry Point 371 368 363 356 351
Cloud Point (CP) ~C 1 0 -2 -2 -2
Pour Point ~C -5 -5 -7 5 7-5 7-5
CFPP ~C -1 -3 -3 -4 -5
Amount of Wax
Separated Out (wt%)
-5~C 0.90 0.82 0.77 0.61 0.53
-10~C 1.64 1.81 2.05 2.32 2.58
CP-10~C 1.52 1.81 2.54 2.93 3.41
Note: CP-10~C is a temperature 10~C below the cloud point.
- 18 -
~ 3~fi40
Table 5
___ n-Paraffin Content (wt.%)
Carbon Number
of n-Paraffin No. 5 No. 6 No. 7 No. 8 No. 9
0.30 0.23 0.21 0.20 0.14
11 0.61 0.56 0.53 0.51 0.42
12 0.93 0.90 0.85 0.83 0.81
13 1.78 1.89 1.95 2.10 2.14
14 2.61 2.59 2.59 2.61 2.61
2.49 2.58 2.63 2.67 2.72
16 2.29 2.47 2.58 2.64 2.67
17 2.42 2.83 3.06 3.41 3.64
18 2.20 2.44 2.58 2.67 2.81
19 1.45 1.55 1.66 1.78 1.88
1.13 1.21 1.32 1.40 1.44
21 0.81 0.85 0.92 0.96 1.01
22 0.69 0.73 0.77 0.80 0.84
23 0.47 0.50 0.50 0.50 0.52
24 0.31 0.31 0.32 0.31 0.30
0.28 0.25 0.20 0.14 0.11
26 0.13 0.11 0.10 0.05 0.05
27 0.06 0.05 0.03 0.00 0.00
28 0.01 0.00 0.00 0.00 0.00
29 0.00 0.00 0.00 0.00 0.00
Total of C25~ 0.48 0.41 0.33 0.19 0.15
Notes: "Total of C25~-" indicates total of n-paraffin having at least
25 carbon atoms.
Gas chromatogram of sample oil No. 5 is shown in Fig. 1.
19
1~336~0
Table 6
A CFPP (C)
Sample No. 5 6 7 8 9
Amount of Addition
300 ppm 2 7 4 1 0
500 ppm 3 12 8 2
Example 3
To sample fuel oils shown in Table 7 was added 500
ppm of Additive A described in Example 2, and CFPP was
measured.
The results of evaluatio of the effect by
temperature decrease from CFPP of the sample fuel oil itself
(~ CFPP) are shown in Table 7 and also in Fig. 2.
Further, for comparison, results obtained using
Additive B and Additive C are shown in Table 7 and Figs. 3
and 4.
Additive B is a 60 wt.% xylene solution of an
ethylene-vinyl acetate copolymer having a vinyl acetate
content of 16.5 wt.%, a number average molecular weight of
2,200.
Additive C is a 60 wt.% xylene solution of an
ethylene-vinyl acetate copolymer having a vinyl acetate
content of 44.6 wt.% and a number average molecular weight
of 1,820.
-20-
~33~640
Table 7
__ Sample No. 10 11 12 13 14
Specific Density 0.85100.8444 0.8488 0.84670.8418
(15/4~C)
Kinematic Viscosity 5.293 4.895 4.379 4.8874.131
(30~C) cSt
Distillation Test (~C)
Initial Boiling Point 197 197 168 210 162.5
10% Boiling Point 259.5 249.5 234 259 216
90% Boiling Point 338 338.5 337 332 343
Dry Point 363 364.5 354 351 362
Cloud Point (CP) ~C -1 -3 -6 -5 -5
Pour Point ~C -2.5 -5 -7.5 -7.5 -7.5
CFPP ~C -3 -3 -6 -5 -5
Amount of ~ax
Separated Out (wt%)
-5~C 1.22 0.88 0.00 0.000.00
-10~C 2.75 2.03 1.96 2.101.80
CP-10~C 3.21 2.46 5.13 4.613.90
Content of
n-Paraffin (~C)
Total 20.63 21.07 19.68 21.7719.42
C20-< 4.21 3.85 3.69 3.443.81
C25~ 0.21 0.22 0.05 0.040.10
CFPP (~C)
Additive A 2 3 0 0
Additive B 0 1 0 0 0
Additive C 0 1 0 0 0
Note: CP-10~C is a temperature 10~C below the cloud point.
~ 339~0
Table 7 (Continued)
Sample No. 15 16 17 18 19
Specific Density 0.84630.8290 0.8340 0.8450 0.8550
(15/4~C)
Kinematic Viscosity 4.050 2.960 4.556 4.720 4.511
(30~C) cSt
Distillation Test ( C)
Initial Boiling Point 166 191 175 207 208.5
10% Boiling Point 224 236 229 253.5 250.5
90% Boiling Point 334 346 342.5 325.5 318
Dry Point 353 368 364 342 337
Cloud Point (CP) ~C -5 0 -3 -11 -12
Pour Point ~C -7.5 -5 -7.5 -12.5 -12.5
CFPP ~C -5 -3 -5 -11 -13
Amount of Wax
Separated Out (wt%)
-5~C 0.00 0.84 0.62 0.00 0.00
-10~C 1.65 1.68 1.75 0.00 0.00
CP-10~C 3.55 1.68 2.41 5.23 6.71
Content of
n-Paraffin (~C)
Total 20.18 19.63 19.26 17.69 18.60
C20~ 3.52 3.70 3.37 2.02 1.52
C25-' 0.04 0.36 0.24 0.01 0.00
CFPP (~C)
Additive A 0 11 8 0 0
Additive B 0 3 3 0 0
Additive C 0 3 3 0 0
Note: CP-10~C is a temperature 10~C below the cloud point.
--22 -
1339
Table 7 (Continued)
Sample No. 20 21 22 23 24
Specific Density 0.8485 0.84720.8510 0.86300.8615
(15/4~C)
Kinematic Viscosity 5.482 5.469 5.349 5.2025.216
(30~C) cSt
Distillation Test ( C)
Initial Boiling Point 234 224.5 221 204 207
10% Boiling Point 265 263.5 240 247 245
90% Boiling Point 328 325 345 360.5 362
Dry Point 348 340 367 381 381
Cloud Point (CP) ~C -2 -2 4 7 7
Pour Point ~C -5 -7.5 -2.5 0
CFPP C 5
Amount of Wax
Separated Out (wt%)
-5~C 0.26 0.61 1.13 1.70 1.65
-10~C 3.13 3.09 3.78
CP-10~C 3.62 4.11 0.91 1.210.74
Content of
n-Paraffin (~C)
Total 24.46 25.30 21.81 13.9816.69
C20 c 3.61 3.42 4.50 3.984.36
C25C 0.23 0.11 0.46 0.78 0.67
A CFpp (~C)
Additive A 3 0 8 0 0
Additive B 1 0 2 0 0
Additive C 0 0 2 0 0
Note: CP-10~C is a temperature 10~C below the cloud point.
- 23 -
13 39 6AO
Table 7 (Continued)
Sample No. 25
Specific Density 0.8602
~15/4~C)
Kinematic Viscosity 4.613
(30~C) cSt
Distillation Test ( C)
Initial Boiling Point 190
10% Boiling Point 250
90% Boiling Point 335
Dry Point 359
Cloud Point (CP) ~C ~
Pour Point ~C -2
CFPP ~C -2.5
Amount of Wax
Separated Out (wt%)
-5~C 2.06
-10~C 4.32
CP-10~C 4.32
Content of
n-Paraffin (~C)
Total 20.77
C20 ~ 4.22
C25~ 0.27
A CFPP ( C)
Additive A 0
Additive B 0
Additive C 0
Note: CP-10~C is a temperature 10~C below the cloud point.
- 24 -
13.396iO
E~CT OF THE INVENTION
As evident from the above-described examples, sample oils
which contained n-paraffin having at least 25 carbon atoms in an
amount of below 0.1 wt.% or not smaller than 0.6 wt.% and wax
component which separated out at a temperature 10~C below the cloud
point in an amount of not smaller than 4 wt.% did not exhibit effect
of decreasing CFPP by the addtition of a cold flowability improver.
In contrast, those oils which contained n-paraffin in an amount of not
smaller than 0.1 wt.% and below 0.6 wt.% and wax component which
separated out at a temperature 10 ~C below the cloud point in an
amount of below 4 wt.% showed decrease in CFPP with the cold
flowability improver. Thhis effect was much more excellent with
sample oils of which the wax content was not smaller than 0.2 wt.% and
below 0.5 wt.%.
Further, CFPP of fuel oils decreased widely particularly
when an ethylene-vinyl acetate copolymer having an ethylene content of
60 to 80 wt.% and a number average molecular weight of 1,000 to 4,000
was used as a cold flowability improver. Among them, remarkable
effect was observed with those copolymers which had a molecular weight
distribution of not greater than 4.0 and contained not more than 6
methyl terminated side chains per 100 methylene units.
- 25-
