Note: Descriptions are shown in the official language in which they were submitted.
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FUEL ADDITIVE COMPOSITION AND METHOD FOR TREATMENT OF MIDDLE
DISTILLATE FUELS AND GASOLINE
TECHNICAL FIELD
[0001] The present invention relates to a fuel additive composition and a
method of treating fuels. More particularly, the present invention relates to
a
composition and method of treating fuels such as middle distillate fuels and
gasoline
to improve performance, increase lubricity, increase storage stability,
increase
combustion efficiency and decrease harmful emissions.
BACKGROUND ART
[0002] Ongoing efforts have been made over the years to control the
emissions created by the use of hydrocarbon fuels and to increase the
performance
of such fuels. One method that has been used is to increase the oxygen content
of
the fuels, for example by adding ethanol, as is done in the Midwest region of
the
United States, or by adding methyl tertiary butyl ether (MTBE), as is required
in
California and in major U.S. cities. However, MTBE is quite water soluble and
the
ground water in many parts of the United States is contaminated by MTBE.
However, MTBE itself is a pollutant since it is very water-soluble and any
fuel leak
will pollute ground water with MTBE. Other proposed methods of increasing the
oxygen content of fuels include adding ethers alone or adding ethers mixed
with
alcohols. Alcohols have the disadvantage that fuels that contain alcohols can
become acidic from air oxidation of the alcohol and can form solids hat will
plug
filters and injectors if the fuel is stored for a long period of time.
Further, alcohol
compounds impart no lubricity to the fuel and can make the fuel more
corrosive.
[0003] Peroxides have also been proposed as a source of oxygen for fuels,
but peroxides are unstable and can cause the chemical breakdown of fuel in
storage
tanks, which makes the fuel unusable.
[0004] At the present time, there is a need for a product that has both a
capability of effectively controlling harmful emissions in fuels such as
middle distillate
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fuels and gasoline and a chemical compatibility with such fuels, so that the
fuels
remain stable for long periods of time under typical storage conditions.
DISCLOSURE OF THE INVENTION
[0005] Accordingly, it is an object of the present invention to provide a fuel
additive package that overcomes all of the previous mentioned disadvantages.
[0006] It is another object of the present invention to provide increased
lubricity for gasoline and middle distillate fuels or of synthetic fuels
having the qualities
of gasoline or middle distillate fuels to increase the operating lifetime of
fuel handling
components such as fuel pumps.
[0007] It is another object of the present invention to increase the storage
lifetime of gasoline and middle distillate fuels, and of synthetic fuels
having the qualities
of gasoline or middle distillate fuels.
[0008] It is another object of the present invention to increase combustion
efficiency and thus reduce harmful emissions of engines using gasoline, middle
distillate fuels and synthetic fuels having the qualities of gasoline or
middle distillate
fuels.
[0009] It is another object of the present invention to provide an additive
that
can increase power and mileage of vehicles that use middle distillate fuels,
gasoline or
synthetic fuels having the qualities of gasoline or middle distillate fuels.
[0010] It is another object of the present invention to provide an additive
that
increases the thermal energy yield of middle distillate fuels used as heating
oil.
[0011] These and other objects of the present invention are obtained by a fuel
additive for middle distillate fuels comprising a mixture of (i) at least one
alkyl ester of a
vegetable oil or at least one methyl, ethyl, propyl or butyl ester of a C~s -
C~a fatty acid,
(ii) at least one alkyl ether of propylene glycol, (iii) a surfactant, and
(iv) an antioxidant.
These and other objects of the present invention are obtained by a fuel
additive for
gasoline comprising a mixture of (i) at least one of ligroin or toluene, or
xylene (ii) at
least one alkyl ether of propylene glycol, (iii) a surfactant, and (iv)
tertiary amyl methyl
ether (TAME).
[0012] These mixtures accomplish an increase or improvement of
performance, lubricity, storage stability, combustion efficiency, and a
simultaneous
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decrease in emissions. The present invention has many advantages over prior
art.
The present invention uses environmentally safe (benign by design) materials.
The
use of vegetable oils such as soybean derived liquids, the use of
polypropylene
compounds which are much safer for both personnel and the environment compared
to ethylene glycol materials. Also the current invention improves operating
characteristics in addition to reducing harmful emissions.
BEST MODE FOR CARRYING OUT THE INVENTION
Composition for Middle Distillate Fuels
[0013] The term "middle distillate fuels" is used herein with the meaning as
commonly understood in the art as the middle cut in a distillation of
petroleum where
gasoline is the top cut (having the lowest boiling point) and heavy fuel oils
for boilers
and electrical generation stations are at the bottom. Typically, middle
distillate fuels
consist of about 50 major components and several thousand minor constituents.
The
most common usage of middle distillate fuels is diesel ground transportation
fuel, jet
fuel, heating and electrical generation. The terms middle distillate fuel and
diesel fuel
(and the term diesel is to be understood to include Grades 7-6) may be used
interchangeably herein without implying a limitation of either term. The term
"middle
distillate fuels" as used herein is also meant to apply to pure compounds or
mixtures
of a fewer compounds that are derived from middle distillate fuels or are
synthesized
de novo and have substantially the same properties and uses as middle
distillate
fuels derived from natural sources. The term "middle distillate fuels" as used
herein
also refers to home heating oil, which typically differs from diesel fuel only
in that
diesel fuel typically contains a dye so that it can be distinguished for tax
purposes.
The composition of the present invention does not affect the dye or its
chemical
stability. For convenience, the required dye could be added to the fuel
additive
composition of the present invention.
[0014] With respect to middle distillate fuels, the preferred additive
composition according to the present invention is a mixture of (i) at least
one
methyl, ethyl, propyl or butyl ester of a vegetable oil or of a C~6 - C~$
fatty acid, (ii)
at least one alkyl ether of propylene glycol, (iii) a surfactant, and (iv) an
antioxidant.
(0015] Without being limited to a particular theory, it is believed that the
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ester of a vegetable oil or of a C~6 - C~$ fatty acid in the composition for
middle
distillate fuels of the present invention serves at least three functions in
the present
invention. First, it provides an internal source of oxygen to make combustion
more
complete and thus lower harmful emission products. Second, because of its
ester
chemical structure, it provides lubricity to the fuel. This provides the added
benefit
of increasing the lifetime of all fuel handling components such as pumps and
injectors and drastically lowers vehicle maintenance costs. Third, because
these
esters are powerful solvents, they can help to keep the fuel system clean.
Because
the esters are stable at high temperatures, they can help to clean fuel system
components such as fuel injectors, which typically become hot during the
operation
of an engine.
[0016] The ester component of the present composition may be obtained
by esterifying any vegetable oil, including recycled cooking oil. The ester
component may be esters of mixtures of different vegetable oils. Preferably,
the
vegetable oil is soybean oil, which typically has the composition set forth in
Table 1:
Table 1. Distribution of Fatty Acids in Soybean Oil
carbon number fatty acid concentration (wt%)
C~$ linoleic 53
C~$ oleic 24
C~$ linolenic 3
C~$ stearic 10
C,~ palmitic 10
[0017] Alternatively, the ester component of the present composition may
be derived from any natural or artificial source of C~6 - C~$ fatty acids. For
example,
a pure C~6 to C,8 fatty acid ester may be used, or mixtures of C~6 - C~Bfatty
acid
esters.
[0018] The ester component is preferably a methyl ester, but may also be
an ethyl, propyl or butyl ester. Methods of making methyl, ethyl, propyl or
butyl
esters of fatty acids are well known. ,
[0019] Preferably the ester component is contained in the fuel additive
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composition in the amount of 60 - 70% by weight of the fuel additive
composition.
[0020] Without being limited to a particular theory, it is believed that the
propylene glycol alkyl ether in the composition for middle distillate fuels of
the
present invention serves at least two functions. First, it provides an
additional
internal source of oxygen to make combustion more complete and thus lower
harmful emission products. Second, it serves to disperse water that can form
in fuel
systems due to natural variations in temperature and humidity. In diesel
vehicles
fuel systems, water that infiltrates the system contributes to a large
increase in
maintenance costs. The dispersal of this water can serve to lower maintenance
costs associated with the replacement of water separator filters in diesel
fuel
systems. A propylene glycol ether is preferred to other types of ethers such
as
ethylene glycol ether because it is non-toxic and requires no clean-up.
[0021] Preferably, the propylene glycol alkyl ether is propylene glycol butyl
ether (a four carbon alkyl ether), but other ethers can be used. In
particular, the
propylene glycol alkyl ether can be, but is not limited to, any propylene
glycol alkyl
ethers with an alkyl moiety of 1 to 4 carbons (methyl, ethyl, propyl, or
butyl).
[0022] Preferably the propylene glycol alkyl ether is contained in the fuel
additive composition in the amount of 25 - 30 % by weight.
[0023] Without being limited to a particular theory, it is believed that the
surfactant in the composition middle distillate fuels of the present invention
serves
at least three functions including enhancing lubricity, helping to disperse
water, and
providing another internal source of oxygen to thereby reduce harmful
emissions.
The surfactant is selected as a compound capable of providing these functions.
Preferably, the surfactant is a polyoxyethylene isooctylcyclohexyl ether or
branched
polyoxyethylene nonylcyclohexyl ether. Preferably the surfactant is contained
in the
fuel additive composition in the amount of 4 - 10 %.
[0024] Without being limited to a particular theory, it is believed that the
antioxidant in the composition middle distillate fuels of the present
invention serves
at least three functions including enhancing lubricity, providing another
internal
source of oxygen and reducing fuel degradation. The antioxidant is selected as
a
compound capable of providing these functions and is preferably a alkyl
substituted
phenol. In particular, the preferred antioxidant is a methyl, ethyl, propyl,
or butyl-
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substituted phenol. Most preferably, the antioxidant is a 2- or 4-tent-butyl
pheno~.
[0025] Preferably the antioxidant is contained in the fuel additive
composition in the amount of about 0.5 to 3.0 % by weight.
[0026] A preferred composition for the additive for middle distillate fuels is
set forth in Table 2 as follows:
Table 2. Preferred Composition for the Additive for Middle Distillate Fuels
Additive Component Concentration
Methyl ester of soybean oil 60 - 70 % by weight
Propylene glycol butyl ether 25 - 30 % by weight
polyoxyethylene isooctylcyclohexyl ether or
branched polyoxyethylene nonylcyclohexyl ether 4 -10 % by weight
2 or 4-tert butyl phenol 0.5 - 3 % by weight
For winter operation, 1 % by weight of glycerin ketals can be added for anti-
icing.
[0027] The formulation described above is not sensitive as to the order of
the constituents being added. The ingredients mix with ease and are not
sensitive
to normal environmental temperature or humidity conditions in which fuels are
handled and used. The ester (component (i)) can be industrially made from food
grade soy bean oil and thus represents no hazard in comparison to the diesel
fuel
itself. Thus, the additive formulation described above minimizes personnel and
health exposures. In a middle distillate fuel, the components described above
interact synergistically to provide a significant increase in performance and
lower
maintenance costs in diesel powered vehicles and in heating systems.
[0028] Another aspect of the present invention is a middle distillate fuel
composition containing a middle distillate fuel and the above-described
additive,
wherein the additive is present in an amount of up to 0.1 % by weight of the
total
composition.
[0029] Another aspect of the present invention is a method of treating a
middle distillate fuel by adding the above-described additive to the middle
distillate
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fuel in an amount of up to 0.1 % by weight of the total composition. The
method of
treatment may, for example, reduce harmful emissions from combustion of the
middle distillate fuel, increase performance and power and reduce engine wear
of
an engine using the middle distillate fuel containing the additive. If the
middle
distillate fuel is used in a heating system, the additive may provide
increased
performance, reduced emissions and lower maintenance costs. Further, a middle
distillate fuel treated by the addition of the fuel additive as described
above may
show greater storage stability.
Composition for Gasoline
[0030] The term "gasoline" is used herein with the meaning as commonly
understood in the art as a hydrocarbon fuel derived from a distillation
fraction
containing compounds ranging from about C4 to Coo. Typically, gasoline
consists of
40-50 major components and another 40 or so minor constituents. The term
"gasoline" as used herein is also meant to apply to pure compounds or mixtures
of
fewer compounds that are derived from gasoline or are synthesized de novo and
have substantially the same properties and uses as gasoline fuels derived from
natural sources.
[0031] With respect to gasoline, the preferred additive composition is a
mixture of (i) at least one of ligroin or toluene/xylene, (ii) at least one
alkyl ether of
propylene glycol, (iii) a surfactant, and (iv) tertiary amyl methyl ether
(TAME).
(0032] Ligroin, also commonly referred to as petroleum ether, is a material
that is available in several different temperature ranges and can be
formulated by
temperature for the region in which the gasoline is to be consumed. An example
of
a temperature range is 90°-110°C, but other temperature ranges
may be used.
Alternatively, toluene or xylene or a mixture of toluene and xylene may be
used to
increase the octane rating. Typically, toluene and xylene are already present
in
gasoline, and the increase in the concentration of these compounds can serve
to
increase the octane rating. Preferably, the ligroin or toluene/xylene is
present in the
additive composition in the amount of 50 - 70 % by weight.
(0033] As in the composition for middle distillate fuels, without being
limited to a particular theory, it is believed that the propylene glycol alkyl
ether in the
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composition for gasoline of the present invention serves the functions of
providing,
an additional internal source of oxygen to make combustion more complete and
thus lowering harmful emission products and serving to disperse water that can
form in fuel systems due to natural variations in temperature and humidity.
Preferably, the propylene glycol alkyl ether is propylene glycol butyl ether
(a four
carbon alkyl ether), but other ethers can be used. In particular, the
propylene glycol
alkyl ether can be, but is not limited to, any propylene glycol alkyl ethers
with an
alkyl moiety of 1 to 4 carbons (methyl, ethyl, propyl, or butyl). Preferably
the
propylene glycol alkyl ether is contained in the fuel additive composition in
the
amount of 25 - 30 % by weight.
[0034] As in the composition for middle distillate fuels, without being
limited to a particular theory, it is believed that the surfactant in the
composition for
gasoline of the present invention serves at least three functions including
enhancing
lubricity, helping to disperse water, and providing another internal source of
oxygen
to thereby reduce harmful emissions. The surfactant is selected as a compound
capable of providing these functions. Preferably, the surfactant is a
polyoxyethylene
isooctylcyclohexyl ether or branched polyoxyethylene nonylcyclohexyl ether.
Preferably the surfactant is contained in the fuel additive composition in the
amount
of4-9%.
[0035] The composition for gasoline of the present invention further
contains tertiary amyl methyl ether (TAME) as an internal source of oxygen.
Preferably, the TAME is contained in the fuel additive composition in the
amount of
0.5 - 3%.
[0036] A preferred composition for the additive for middle distillate fuels is
set forth in Table 3 as follows:
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Additive Component Concentration
Ligroin (90° - 110°C) or toluene/xylene 50 - 70% by weight
Propylene glycol butyl ether 25 - 30% by weight
Polyoxyethylene isooctylcyclohexyl ether or
branched polyoxyethylene nonylcyclohexyl ether 4 -19 % by weight
Tertiary amyl methyl ether 0.5 - 3 % by weight
[0037] The formulation described above is not sensitive as to the order of
the constituents being added. The ingredients mix with ease and are not
sensitive
to normal environmental temperature or humidity conditions in which fuels are
handled and used. Thus, the additive formulation described above minimizes
personnel and health exposures.
[0038] In gasoline, the components described above interact
synergistically to provide a dramatic increased performance in gasoline
engines.
[0039] Another aspect of the present invention is a gasoline composition
containing gasoline and the above-described additive, wherein the additive is
present in an amount of up to 0.1 % by weight of the total composition.
[0040] Another aspect of the present invention is a method of gasoline by
adding the above-described additive to the gasoline in an amount of up to 0.1
% by
weight of the total composition. The method of treatment may, for example,
reduce
harmful emissions from combustion of the gasoline, increase performance and
power and reduce engine wear of an engine using gasoline containing the
additive.
Further, gasoline treated by the addition of the fuel additive as described
above
may show greater storage stability.
EXAMPLES
[0041] Having described the invention, the following examples are given to
illustrate specific applications of the invention, including the best mode now
known
to perform the invention. These specific examples are not intended to limit
the
scope of the invention described in this application.
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[0042] A fuel additive composition for middle distillate fuels is made by
blending the following ingredients:
Methyl ester of soybean oil 60 % by weight
Propylene glycol butyl ether 30 % by weight
Polyoxyethylene isooctylcyclohexyi ether or
branched polyoxyethylene nonylcyclohexyl ether 9 % by weight
2- or 4-tent Butyl phenol 1 % by weight
(0043] The fuel additive composition is added to a middle distillate fuel in
the
amount of up to 0.1 % by weight.
EXAMPLE 2
[0044] A fuel additive composition for gasoline is made by blending the
following ingredients:
Ligroin (90°-110°C) 60% by weight
Propylene glycol butyl ether 30% by weight
Polyoxyethylene isooctylcyclohexyl ether or
branched polyoxyethylene nonylcyclohexyl ether 9% by weight
Tertiary amyl methyl ether 1 % by weight
[0045] The fuel additive composition is added to a middle distillate fuel in
the
amount of up to 0.1 % by weight.
[0046] Obviously, many modifications and variations of the present invention
are possible in light of the above teachings. It is therefore to be understood
that, within
the scope of the appended claims, the invention may be practiced otherwise
than as
specifically described.
