U.S. patent application number 12/262067 was filed with the patent office on 2009-06-18 for blends for use in fuel compositions.
Invention is credited to Christopher William CLAYTON.
Application Number | 20090151230 12/262067 |
Document ID | / |
Family ID | 39232041 |
Filed Date | 2009-06-18 |
United States Patent
Application |
20090151230 |
Kind Code |
A1 |
CLAYTON; Christopher
William |
June 18, 2009 |
BLENDS FOR USE IN FUEL COMPOSITIONS
Abstract
A blend composition comprising (i) one or more base fuels having
an aromatics content of below 80% by weight, said one or more base
fuels being present in the amount of 10 to 95% by weight of the
blend composition; (ii) a fuel additive mixture comprising one or
more fuel additives, wherein said additives include an anti-foam
agent, said fuel additive mixture being present preferably in the
amount of 0.01 to 80% by weight of the blend composition; (iii) an
organic molecule containing a moiety CR.sub.1R.sub.2R.sub.3(OH)
wherein R.sub.1, R.sub.2 and R.sub.3 are each independently
hydrogen or an organic carbon-containing group; and optionally (iv)
an aromatic solvent having an aromatics content of greater than 80%
by weight; a process for the preparation of said blend composition;
and a fuel composition comprising a second base fuel and said blend
composition.
Inventors: |
CLAYTON; Christopher William;
(Chester, GB) |
Correspondence
Address: |
SHELL OIL COMPANY
P O BOX 2463
HOUSTON
TX
772522463
US
|
Family ID: |
39232041 |
Appl. No.: |
12/262067 |
Filed: |
October 30, 2008 |
Current U.S.
Class: |
44/302 |
Current CPC
Class: |
C10L 1/1616 20130101;
C10L 1/14 20130101; C10L 1/28 20130101; C10L 1/1824 20130101; C10L
1/285 20130101; C10L 1/143 20130101 |
Class at
Publication: |
44/302 |
International
Class: |
C10L 1/18 20060101
C10L001/18 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 30, 2007 |
EP |
07119654.7 |
Claims
1. A blend composition comprising (i) one or more base fuels having
an aromatics content of below 80% by weight, said one or more base
fuels being present in the amount of 10 to 95% by weight of the
blend composition; (ii) a fuel additive mixture comprising one or
more fuel additives, wherein said additives include an anti-foam
agent, said fuel additive mixture being present preferably in the
amount of 0.01 to 80% by weight of the blend composition; (iii) an
organic molecule containing a moiety CR.sub.1R.sub.2R.sub.3(OH)
wherein R.sub.1, R.sub.2 and R.sub.3 are each independently
hydrogen or an organic carbon-containing group; and optionally (iv)
an aromatic solvent having an aromatics content of greater than 80%
by weight.
2. The blend composition of claim 1 wherein said aromatic solvent
has an aromatics content of greater than 85% by weight.
3. The blend composition of claim 2 wherein said aromatic solvent
has an aromatics content of greater than 90% by weight.
4. The blend composition of claim 3 wherein said aromatic solvent
has an aromatics content of greater than 95% by weight.
5. The blend composition of claim 1 wherein each said base fuel has
an aromatics content of below 50% by weight.
6. The blend composition of claim 5 wherein each said base fuel has
an aromatics content of below 35% by weight.
7. The blend composition of claim 5 is selected from gas oils and
kerosene fuels.
8. The blend composition of claim 1 wherein said organic molecule
is an alkyl alcohol.
9. The blend composition of claim 2 wherein said organic molecule
is an alkyl alcohol.
10. The blend composition of claim 5 wherein said organic molecule
is an alkyl alcohol.
11. The blend composition of claim 8 wherein said organic molecule
is selected from C.sub.3-30 alkyl alcohols.
12. The blend composition of claim 11 wherein said organic molecule
is selected from C.sub.4-20 alkyl alcohols.
13. The blend composition of claim 12 wherein said organic molecule
is selected from C.sub.7-10 alkyl alcohols.
14. The blend composition of claim 13 wherein said organic molecule
and is 2-ethylhexanol.
15. The blend composition of claim 1 comprising said base fuel(s)
in the amount of 10 to 85% by weight of said composition.
16. The blend composition of claim 15 comprising said aromatic
solvent in the amount of 0 to 65% by weight of said
composition.
17. The blend composition of claim 15 comprising said organic
molecule in the amount of 0.01 to 30% by weight of said
composition.
18. A process for the preparation of a blend composition comprising
blending (i) one or more base fuels having an aromatics content of
below 80% by weight, said one or more base fuels being present in
the amount of 10 to 95% by weight of the blend composition; (ii) a
fuel additive mixture comprising one or more fuel additives,
wherein said additives include an anti-foam agent, said fuel
additive mixture being present preferably in the amount of 0.01 to
80% by weight of the blend composition; (iii) an organic molecule
containing a moiety CR.sub.1R.sub.2R.sub.3(OH) wherein R.sub.1,
R.sub.2 and R.sub.3 are each independently hydrogen or an organic
carbon-containing group; and optionally (iv) an aromatic solvent
having an aromatics content of greater than 80% by weight.
19. A fuel composition comprising a second base fuel and a blend
composition of claim 1, wherein said second base fuel may the same
as or different from the base fuel in said blend composition.
20. The blend composition of claim 1 wherein said anti-foam agent
comprises a silicone-containing anti-foam agent.
21. The blend composition of claim 20 wherein said anti-foam agent
comprises a polyether-modified polysiloxane.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a blend of a fuel additive
mixture and one or more solvents. It also relates to a fuel
composition comprising a base fuel, particularly a gas oil, such as
an automotive gas oil, and such a blend.
BACKGROUND OF THE INVENTION
[0002] A fuel composition includes a number of additive components,
which impart various performance or handling advantages to the fuel
composition. Such components are commonly provided and used in the
form of an additive mixture containing one or more of said
components and one or more solvents. Said solvents provide one or
more functions to the mixtures, for example to reduce the
concentration of an additive component to a level at which it is
safe to handle, or to dissolve an additive component that exhibits
low solubility in hydrocarbons, or for other reasons.
[0003] It has been found that certain commercially available
products, that are marketed for use as solvents, have the
properties that are required, but that it can be desirable, for
cost or availability reasons, to find alternative materials that
are suitable solvents for use in this context.
SUMMARY OF THE INVENTION
[0004] In one aspect of the invention, a blend composition
comprising (i) one or more base fuels having an aromatics content
of below 80% by weight, said one or more base fuels being present
in the amount of 10 to 95% by weight of the blend composition; (ii)
a fuel additive mixture comprising one or more fuel additives,
wherein said additives include an anti-foam agent, said fuel
additive mixture being present preferably in the amount of 0.01 to
80% by weight of the blend composition; (iii) an organic molecule
containing a moiety CR.sub.1R.sub.2R.sub.3(OH) wherein R.sub.1,
R.sub.2 and R.sub.3 are each independently hydrogen or an organic
carbon-containing group; and optionally (iv) an aromatic solvent
having an aromatics content of greater than 80% by weight.
[0005] In another aspect of the invention, a process for preparing
the blend composition and a fuel composition containing the blend
is provided.
DETAILED DESCRIPTION OF THE INVENTION
[0006] It has now been found that the solvency properties of a
commercially available solvent can be provided by a base fuel such
as an automotive gas oil (diesel) or a jet fuel. In particular, it
has been found that solvency properties of such a commercially
available solvent when used in a blend containing a fuel additive
mixture which comprises an anti-foam agent can be provided by at
least partially replacing said solvent by a base fuel such as an
automotive gas oil or jet fuel, each having a low aromatics
content, when also including in said blend an organic molecule
containing a moiety CR.sub.1R.sub.2R.sub.3(OH) wherein R.sub.1,
R.sub.2 and R.sub.3 are each independently hydrogen or an organic
carbon-containing group, an example of such a molecule being an
alkyl alcohol. This enables such blends to maintain good stability
even when using materials that are cheaper and more widely
available than commercially available solvents.
[0007] For example, it has been found that the stability of a blend
of a fuel additive mixture and `Caromax 20` aromatic solvent
(available ex. Petrochem Carless) can be provided when replacing at
least some of said solvent in said blend by a low aromatics
automotive gas oil and including in said blend 2-ethylhexanol.
[0008] U.S. Pat. No. 5,385,588 describes an additive concentrate
package having an enhanced shelf-life stability which comprises a
solvent stabiliser composition that contains at least one liquid
aromatic hydrocarbon solvent and at least one liquid alkyl or
cycloalkyl alcohol, e.g. 2-ethylhexanol. Preferred aromatic
hydrocarbon solvents are described as being selected from toluene,
ethylbenzene, xylene, and mixtures of o-, p- and m-xylenes,
mesitylene, and higher boiling aromatic mixtures such as `Super
High Flash Naphtha`, Aromatic 150` and `Aromatic 100`. The
aromatics contents of said commercially available higher boiling
aromatic mixtures are >80%, >99 vol % and >99 vol %,
respectively, i.e. high aromatics contents. However, there is no
mention of the aromatic hydrocarbon solvent being a gas oil or jet
fuel, nor of a low aromatics material. Solvents having low
aromatics levels are known to be poor solvents for the types of
additives in question.
[0009] Lack of stability of the blends can manifest itself as
follows. As the atmospheric temperature falls, a blend that is a
single-phase homogeneous liquid at normal temperatures may become a
multiphase liquid as certain components either (i) freeze (forming
a solid) or (ii) become immiscible in the bulk liquid and form a
separate liquid layer. The onset of formation of a solid on cooling
is characterised by a change in the transparency of the blend and
the temperature at which this occurs is termed the "Cloud Point" of
the fuel. If, on cooling, the Cloud Point is preceded by the
formation of a separate liquid phase, the temperature at which this
occurs is termed the "Phase separation temperature".
[0010] In accordance with the present invention there is provided a
blend composition comprising (i) one or more base fuels having an
aromatics content of below 80% by weight, said one or more base
fuels being present in the amount of 10 to 95% by weight of the
blend composition; (ii) a fuel additive mixture comprising one or
more fuel additives, wherein said additives include an anti-foam
agent, said fuel additive mixture being present preferably in the
amount of 0.01 to 80% by weight of the blend composition; (iii) an
organic molecule containing a moiety CR.sub.1R.sub.2R.sub.3(OH)
wherein R.sub.1, R.sub.2 and R.sub.3 are each independently
hydrogen or an organic carbon-containing group; and optionally (iv)
an aromatic solvent having an aromatics content of greater than 80%
by weight.
[0011] In particular, it has been found that additive packages or
mixtures containing a silicone anti-foam agent, for example a
polyether-modified polysiloxane, have a tendency especially at low
temperature to deposit a separate liquid phase containing silicone,
plus all other components present which have partitioned themselves
between the low aromatics hydrocarbon solvent phase and the
silicone phase, but that this separation does not occur if the
solvent system contains alcohol in addition to the low aromatics
hydrocarbon.
[0012] "Base fuel" is defined as being a material that is in
accordance with one or more published base fuel standard
specifications.
[0013] Preferably, said aromatic solvent has an aromatics content
of greater than 85% by weight, more preferably greater than 90% by
weight, most preferably greater than 95% by weight. Suitable such
aromatic solvents include `Caromax 20` (ex. Petrochem Carless) and
`Solvesso 200` (ex. ExxonMobil).
[0014] Preferably, each said base fuel has an aromatics content of
below 50% by weight, more preferably below 35% by weight. It is
preferably selected from gas oils, such as automotive gas oils, and
kerosene fuels, such as jet fuels.
[0015] Preferably, each said base fuel has a cloud point of below
-5.degree. C., more preferably below -15.degree. C., yet more
preferably below -20.degree. C., most preferably below -25.degree.
C.
[0016] Preferably, said organic molecule is an alkyl alcohol, which
more preferably is selected from C.sub.3-30 alkyl alcohols, still
more preferably from C.sub.4-20 alkyl alcohols, yet more preferably
from C.sub.7-10 alkyl alcohols, such as 2-ethylhexanol, octan-1-ol
and octan-2-ol, and is most preferably 2-ethylhexanol.
[0017] Preferably, said one or more published base fuel standard
specifications are selected from EN 590, Swedish Class 1 (as
defined by the Swedish Standard for EC1), ASTM D975 and Defence
Standard 91-91 (Def Stan 91-91) specifications. EN 590:2004 is the
current European Standard for diesel fuels. SS 155435:2006 is the
current Swedish Standard for EC1. ASTM D975-07a is the current
United States Standard Specification for Diesel Fuel Oils. Def Stan
91-91 Issue 5 Amendment 2 is the current UK standard for Turbine
Fuel, Aviation Kerosine Type, Jet A-1.
[0018] Preferably, the concentration of the fuel additive mixture
in the blend composition accords with one or more of the following
parameters:
[0019] (i) at least 10%; (ii) at least 20%; (iii) at least 30%;
(iv) at least 40%; (v) up to 60%; (vi) up to 70%; by weight, with
the range having features (i) and (vi) being preferred.
[0020] Preferably, the concentration of the anti-foam agent in the
blend composition accords with one or more of the following
parameters:
[0021] (i) at least 0.025%; (ii) at least 0.05%; (iii) at least
0.075%; (iv) at least 0.1%; (v) up to 2%; (vi) up to 2.5%; by
weight, with the range having features (i) and (vi) being
preferred.
[0022] Preferably, the concentration of the base fuel(s) in the
blend composition accords with one or more of the following
parameters:
[0023] (i) at least 10%; (ii) at least 20%; (iii) at least 30%;
(iv) at least 50%; (v) up to 75%; (vi) up to 85%; by weight, with
the range having features (i) and (vi) being preferred.
[0024] Preferably, the concentration of the aromatic solvent in the
blend composition accords with one or more of the following
parameters:
[0025] (i) 0%; (ii) at least 1%; (iii) at least 2%; (iv) at least
3%; (v) at least 5%; (vi) up to 10%; (vii) up to 15%; (viii) up to
35%; (ix) up to 50%; (x) up to 65%; by weight, with ranges having
features (i) and (x), (ii) and (ix), (iii) and (viii), and (iv) and
(vii) respectively being progressively more preferred. The ranges
having features (i) and (ix), (i) and (viii), (ii) to (vii), and
(i) are also preferred.
[0026] Preferably, the concentration of said organic molecule in
the blend composition accords with one or more of the following
parameters:
[0027] (i) at least 0.01%; (ii) at least 1%; (iii) at least 5%;
(iv) up to 15%; (v) up to 20%; (vi) up to 30%; by weight, with
ranges having features (i) and (vi), (ii) and (v), and (iii) and
(iv) respectively being progressively more preferred. The ranges
having features (ii) and (vi), and (i) and (iv) are also
preferred.
[0028] In accordance with the present invention, there is also
provided a process for the preparation of a blend composition which
process comprises blending (i) one or more base fuels having an
aromatics content of below 80% by weight, said one or more base
fuels being present in the amount of 10 to 95% by weight of the
blend composition; (ii) a fuel additive mixture comprising one or
more fuel additives, wherein said additives include an anti-foam
agent, said fuel additive mixture being present preferably in the
amount of 0.01 to 80% by weight of the blend composition; (iii) an
organic molecule containing a moiety CR.sub.1R.sub.2R.sub.3(OH)
wherein R.sub.1, R.sub.2 and R.sub.3 are each independently
hydrogen or an organic carbon-containing group; and optionally (iv)
an aromatic solvent having an aromatics content of greater than 80%
by weight.
[0029] In accordance with the present invention there is further
provided a fuel composition comprising a second base fuel and a
blend composition according to the present invention, wherein said
second base fuel may the same as or different from the base fuel in
said blend composition. Said second base fuel is preferably a gas
oil, more preferably an automotive gas oil (diesel).
[0030] Preferably, said anti-foam agent is a silicone-containing
anti-foam agent, more preferably a polyether-modified
polysiloxane.
[0031] The "fuel additive mixture comprising one or more fuel
additives" is defined as being a mixture of additives in which the
(active matter) concentration of said additives is greater than
10000 ppmw, preferably greater than 50000 ppmw, more preferably
greater than 100000 ppmw, most preferably greater than 150000 ppmw.
Said fuel additive mixture, and the blend composition of the
present invention which comprises said fuel additive mixture, may
in practice each be termed a "fuel additive package".
[0032] The fuel composition comprising said blend composition will
typically contain a major proportion of the second base fuel, such
as from 50 to 99.95% v, preferably from 80 to 99.95% v, more
preferably from 90 to 99.95% v.
[0033] The fuel compositions to which the present invention relates
include diesel fuels for use in automotive compression ignition
engines, as well as in other types of engine such as for example
marine, railroad and stationary engines, and industrial gas oils
for use in heating applications (e.g. boilers).
[0034] The base fuel may itself comprise a mixture of two or more
different diesel fuel components, and/or be additivated as
described below.
[0035] Such diesel fuels will contain one or more base fuels which
may typically comprise liquid hydrocarbon middle distillate gas
oil(s), for instance petroleum derived gas oils. Such fuels will
typically have boiling points within the usual diesel range of 150
to 400.degree. C., depending on grade and use. They will typically
have a density from 750 to 1000 kg/m.sup.3, preferably from 780 to
860 kg/m.sup.3, at 15.degree. C. (e.g. ASTM D4502 or IP 365) and a
cetane number (ASTM D613) of from 35 to 120, more preferably from
40 to 85. They will typically have an initial boiling point in the
range 150 to 230.degree. C. and a final boiling point in the range
290 to 400.degree. C. Their kinematic viscosity at 40.degree. C.
(ASTM D445) might suitably be from 1.2 to 4.5 mm.sup.2/s.
[0036] An example of a petroleum derived gas oil is a Swedish Class
1 base fuel, which will have a density from 800 to 820 kg/m.sup.3
at 15.degree. C. (SS-EN ISO 3675, SS-EN ISO 12185), a T95 of
320.degree. C. or less (SS-EN ISO 3405) and a kinematic viscosity
at 40.degree. C. (SS-EN ISO 3104) from 1.4 to 4.0 mm.sup.2/s, as
defined by the Swedish national specification EC1.
[0037] Such industrial gas oils will contain a base fuel which may
comprise fuel fractions such as the kerosene or gas oil fractions
obtained in traditional refinery processes, which upgrade crude
petroleum feedstock to useful products. Preferably such fractions
contain components having carbon numbers in the range 5 to 40, more
preferably 5 to 31, yet more preferably 6 to 25, most preferably 9
to 25, and such fractions have a density at 15.degree. C. of 650 to
1000 kg/m.sup.3, a kinematic viscosity at 20.degree. C. of 1 to 80
mm.sup.2/s, and a boiling range of 150 to 400.degree. C.
[0038] Kerosene fuels will typically have boiling points within the
usual kerosene range of 130 to 300.degree. C., depending on grade
and use. They will typically have a density from 775 to 840
kg/m.sup.3, preferably from 780 to 830 kg/m.sup.3, at 15.degree. C.
(e.g. ASTM D4502 or IP 365). They will typically have an initial
boiling point in the range 130 to 160.degree. C. and a final
boiling point in the range 220 to 300.degree. C. Their kinematic
viscosity at -20.degree. C. (ASTM D445) might suitably be from 1.2
to 8.0 mm.sup.2/s.
[0039] Optionally, non-mineral oil based fuels, such as bio-fuels
or Fischer-Tropsch derived fuels, may also form or be present in
the fuel composition. Such Fischer-Tropsch fuels may for example be
derived from natural gas, natural gas liquids, petroleum or shale
oil, petroleum or shale oil processing residues, coal or
biomass.
[0040] The amount of Fischer-Tropsch derived fuel used in a diesel
fuel composition may be from 0% to 100% v of the overall diesel
fuel composition, preferably from 5% to 100% v, more preferably
from 5% to 75% v. It may be desirable for the composition to
contain 10% v or greater, more preferably 20% v or greater, still
more preferably 30% v or greater, of the Fischer-Tropsch derived
fuel. It is particularly preferred for the composition to contain
30 to 75% v, and particularly 30 or 70% v, of the Fischer-Tropsch
derived fuel. The balance of the fuel composition is made up of one
or more other fuels.
[0041] An industrial gas oil composition will preferably comprise
more than 50 wt %, more preferably more than 70 wt %, of a
Fischer-Tropsch derived fuel component.
[0042] Such a Fischer-Tropsch derived fuel component is any
fraction of the middle distillate fuel range, which can be isolated
from the (optionally hydrocracked) Fischer-Tropsch synthesis
product. Typical fractions will boil in the naphtha, kerosene or
gas oil range. Preferably, a Fischer-Tropsch product boiling in the
kerosene or gas oil range is used because these products are easier
to handle in for example domestic environments. Such products will
suitably comprise a fraction larger than 90 wt % which boils
between 160 and 400.degree. C., preferably to about 370.degree. C.
Examples of Fischer-Tropsch derived kerosene and gas oils are
described in EP-A-0583836, WO-A-97/14768, WO-A-97/14769,
WO-A-00/11116, WO-A-00/11117, WO-A-01/83406, WO-A-01/83648,
WO-A-01/83647, WO-A-01/83641, WO-A-00/20535, WO-A-00/20534,
EP-A-1101813, U.S. Pat. No. 5,766,274, U.S. Pat. No. 5,378,348,
U.S. Pat. No. 5,888,376 and U.S. Pat. No. 6,204,426.
[0043] The Fischer-Tropsch product will suitably contain more than
80 wt % and more suitably more than 95 wt % iso and normal
paraffins and less than 1 wt % aromatics, the balance being
naphthenics compounds. The content of sulphur and nitrogen will be
very low and normally below the detection limits for such
compounds. For this reason the sulphur content of a fuel
composition containing a Fischer-Tropsch product may be very
low.
[0044] The fuel composition preferably contains no more than 5000
ppmw sulphur, more preferably no more than 500 ppmw, or no more
than 350 ppmw, or no more than 150 ppmw, or no more than 100 ppmw,
or no more than 70 ppmw, or no more than 50 ppmw, or no more than
30 ppmw, or no more than 20 ppmw, or most preferably no more than
15 ppmw sulphur.
[0045] The base fuel may itself be additivated
(additive-containing) or unadditivated (additive-free). If
additivated, e.g. at the refinery, it will contain minor amounts of
one or more additives selected for example from anti-static agents,
pipeline drag reducers, flow improvers (e.g. ethylene/vinyl acetate
copolymers or acrylate/maleic anhydride copolymers), lubricity
additives, antioxidants and wax anti-settling agents.
[0046] The fuel additives that also may be included in the fuel
additive mixture comprised in the blend composition according to
the present invention are discussed below, with reference to their
inclusion in fuel compositions comprising such blend
compositions.
[0047] Detergent-containing diesel fuel additives are known and
commercially available. Such additives may be added to diesel fuels
at levels intended to reduce, remove, or slow the build up of
engine deposits.
[0048] Examples of detergents suitable for use in fuel additives
for the present purpose include polyolefin substituted succinimides
or succinamides of polyamines, for instance polyisobutylene
succinimides or polyisobutylene amine succinamides, aliphatic
amines, Mannich bases or amines and polyolefin (e.g.
polyisobutylene) maleic anhydrides. Succinimide dispersant
additives are described for example in GB-A-960493, EP-A-0147240,
EP-A-0482253, EP-A-0613938, EP-A-0557516 and WO-A-98/42808.
Particularly preferred are polyolefin substituted succinimides such
as polyisobutylene succinimides.
[0049] The fuel additive mixture may contain other components,
examples being lubricity enhancers; dehazers, (e.g. alkoxylated
phenol formaldehyde polymers); ignition improvers (cetane
improvers) (e.g. 2-ethylhexyl nitrate (EHN), cyclohexyl nitrate,
di-tert-butyl peroxide and those disclosed in U.S. Pat. No.
4,208,190 at column 2, line 27 to column 3, line 21); anti-rust
agents (e.g. a propane-1,2-diol semi-ester of tetrapropenyl
succinic acid, or polyhydric alcohol esters of a succinic acid
derivative, the succinic acid derivative having on at least one of
its alpha-carbon atoms an unsubstituted or substituted aliphatic
hydrocarbon group containing from 20 to 500 carbon atoms, e.g. the
pentaerythritol diester of polyisobutylene-substituted succinic
acid); corrosion inhibitors; reodorants; anti-wear additives;
anti-oxidants (e.g. phenolics such as 2,6-di-tert-butylphenol, or
phenylenediamines such as N,N'-di-sec-butyl-p-phenylenediamine);
metal deactivators; combustion improvers; cold flow improvers; and
wax anti-settling agents.
[0050] The fuel additive mixture may contain a lubricity enhancer,
especially when the fuel composition has a low (e.g. 500 ppmw or
less) sulphur content. In the additivated fuel composition, the
lubricity enhancer is conveniently present at a concentration of
less than 1000 ppmw, preferably between 50 and 1000 ppmw, more
preferably between 70 and 1000 ppmw. Suitable commercially
available lubricity enhancers include ester- and acid-based
additives. Other lubricity enhancers are described in the patent
literature, in particular in connection with their use in low
sulphur content diesel fuels, for example in: [0051] the paper by
Danping Wei and H. A. Spikes, "The Lubricity of Diesel Fuels",
Wear, III (1986) 217-235; [0052] WO-A-95/33805--cold flow improvers
to enhance lubricity of low sulphur fuels; [0053]
WO-A-94/17160--certain esters of a carboxylic acid and an alcohol
wherein the acid has from 2 to 50 carbon atoms and the alcohol has
1 or more carbon atoms, particularly glycerol monooleate and
di-isodecyl adipate, as fuel additives for wear reduction in a
diesel engine injection system; [0054] U.S. Pat. No.
5,490,864--certain dithiophosphoric diester-dialcohols as anti-wear
lubricity additives for low sulphur diesel fuels; and [0055]
WO-A-98/01516--certain alkyl aromatic compounds having at least one
carboxyl group attached to their aromatic nuclei, to confer
anti-wear lubricity effects particularly in low sulphur diesel
fuels.
[0056] It is also preferred that the fuel additive mixture contain
an anti-foam agent in combination with an anti-rust agent and/or a
corrosion inhibitor and/or a lubricity additive.
[0057] Unless otherwise stated, the (active matter) concentration
of each such additive component in the additivated fuel composition
is preferably up to 10000 ppmw, more preferably in the range from
0.1 to 1000 ppmw, advantageously from 0.1 to 300 ppmw, such as from
0.1 to 150 ppmw.
[0058] The (active matter) concentration of any anti-foam agent in
the fuel composition will preferably be in the range from 0.1 to 20
ppmw, more preferably from 0.25 to 15 ppmw, still more preferably
from 0.5 to 10 ppmw, advantageously from 1 to 5 ppmw. The (active
matter) concentration of any dehazer in the fuel composition will
preferably be in the range from 0.1 to 20 ppmw, more preferably
from 1 to 15 ppmw, still more preferably from 1 to 10 ppmw,
advantageously from 1 to 5 ppmw. The (active matter) concentration
of any ignition improver present will preferably be 2600 ppmw or
less, more preferably 2000 ppmw or less, conveniently from 300 to
1500 ppmw. The (active matter) concentration of any detergent in
the fuel composition will preferably be in the range from 5 to 1500
ppmw, more preferably from 10 to 750 ppmw, most preferably from 20
to 500 ppmw. The (active matter) concentration of any cold flow
improver or wax anti-settling agent in the fuel composition will
preferably be in the range from 15 to 750 ppmw, more preferably
from 25 to 500 ppmw, most preferably from 25 to 300 ppmw.
[0059] In the case of a diesel fuel composition, for example, the
fuel additive mixture will typically contain a detergent,
optionally together with other components as described above, and a
diesel fuel-compatible diluent, which may be a mineral oil, a
solvent such as those sold by Shell companies under the trade mark
"SHELLSOL", a polar solvent such as an ester and, in particular, an
alcohol, e.g. hexanol, 2-ethylhexanol, decanol, isotridecanol and
alcohol mixtures such as those sold by Shell companies under the
trade mark "LINEVOL", especially LINEVOL 79 alcohol which is a
mixture of C.sub.7-9 primary alcohols, or a C.sub.12-14 alcohol
mixture which is commercially available.
[0060] The total content of the additives in the fuel composition
may be suitably between 0 and 10000 ppmw and preferably below 5000
ppmw.
[0061] In this specification, amounts (concentrations, % v, ppmw,
wt %) of components are of active matter, i.e. exclusive of
volatile solvents/diluent materials.
[0062] The present invention is particularly applicable where the
fuel composition is used or intended to be used in a direct
injection diesel engine, for example of the rotary pump, in-line
pump, unit pump, electronic unit injector or common rail type, or
in an indirect injection diesel engine. The fuel composition may be
suitable for use in heavy and/or light duty diesel engines.
[0063] As mentioned above, it is also applicable where the fuel
composition is used in heating applications, for example boilers.
Such boilers include standard boilers, low temperature boilers and
condensing boilers, and are typically used for heating water for
commercial or domestic applications such as space heating and water
heating.
[0064] The present invention may lead to any of a number of
advantages, including the ability to reduce solvent cost and/or
reduce constraints on availability of solvent, whilst maintaining
the same storage stability, or achieve increased storage stability
whilst maintaining the same cost and/or same constraints on
availability of solvent.
[0065] The present invention will now be further described by
reference to the following Examples, in which, unless otherwise
indicated, parts and percentages are by weight, and temperatures
are in degrees Celsius:
[0066] Blends were prepared from the following components: [0067] A
Fuel additive mixture containing a number of fuel additive
components, including an anti-foam agent; [0068] B `Caromax 20`
aromatic solvent, aromatics content >99% (available ex.
Petrochem Carless); [0069] C 2-ethylhexanol (available ex.
Aldrich); [0070] D Norwegian Winter Diesel (ex. Shell); and [0071]
E Swedish Class 1 Diesel (ex. Shell)
EXAMPLES
[0072] Component D (in accordance with EN590), used in preparing
the blends, had the properties given in Table 1:
TABLE-US-00001 TABLE 1 Test Fuel property method Component D
Density @ 15.degree. C. IP 365/ 824.5 (kg/m.sup.3) ASTM D4052
Distillation (.degree. C.): IP 123/ ASTM D86 IBP 173 5% 190 10% 194
30% 211 50% 229 65% 245 75% 259 85% 280 90% 296 95% 322 FBP 332
Cetane index IP 498 47.1 [IQT] Kinematic viscosity IP 71/ 2.0 @
40.degree. C. (mm.sup.2/s) ASTM D445 Cloud point (.degree. C.) IP
219 -29 CFPP (.degree. C.) IP 309 -39 Sulphur (mg/kg) ASTM D2622
below 10 Flash point (.degree. C.) IP 34 greater than 55 Aromatics,
% m IP 391 approx. 24
[0073] Component E, used in preparing the blends, was in accordance
with Swedish national specification EC1, the requirements of which
are given in Table 2:
TABLE-US-00002 TABLE 2 Fuel property Requirement Test method Cetane
Index 50 SS-EN ISO 4264 (min) Cetane No. (min) 51 SS-EN ISO 5165
Density @ 15.degree. C. 800-820 SS-EN ISO 3675 (kg/m.sup.3) SS-EN
ISO 12185 Aromatics (% v/v) 5 SS 155116 (max) SS-EN 12916 PAH (%
v/v) (max) 0.02 SS 155116 Sulphur (mg/kg) 10 SS-EN ISO 20846 (max)
SS-EN ISO 20847 SS-EN ISO 20884 Flash point (.degree. C.) 56 SS-EN
ISO 2719 (min) Viscosity @ 40.degree. C. 1.4-4.0 SS-EN ISO 3104
(mm.sup.2/s) IBP (.degree. C.) (min) 180 SS-EN ISO 3405 T95
(.degree. C.) (max) 320 SS-EN ISO 3405 CFPP (.degree. C.) (max)
SS-EN 116 Summer -10 Winter -26 Cloud point (.degree. C.) SS-EN
23015 (max) Summer 0 Winter -16
[0074] Stability testing was conducted by placing the blend sample
in a glass container and then placing the container in a
temperature-controlled cabinet. The temperature within the cabinet
was then set to the required level and a record made of the time of
the start of the test. A rating of the stability of the blend was
performed by visual inspection of when the blend separated into two
phases. The time at which this occurred was recorded, and the
length of time before phase separation could therefore be
calculated.
[0075] The separation of the blend into two phases had the visual
appearance of a small amount of separated material at the bottom of
the container, or in suspension.
[0076] In Table 3 are set out a number of blends that were tested
at -20.degree. C. Each blend contained 19.5% of Component A. The
fuel used was Component D. In respect of each blend is shown the
length of time before phase separation:
TABLE-US-00003 TABLE 3 Maximum length of stability Component B
Component C Component D (days) 15% 0% 65.5% 9 30% 0% 50.5% 9 45% 0%
35.5% 15 60% 0% 20.5% .gtoreq.95* 15% 3.33% 62.17% 27 22.5% 3.33%
54.67% .gtoreq.83* 30% 3.33% 47.17% .gtoreq.100* 45% 3.33% 32.17%
.gtoreq.100* 60% 3.33% 17.17% .gtoreq.100* 0% 6.67% 73.8% 56 15%
6.67% 58.83% .gtoreq.116* 30% 6.67% 43.83% .gtoreq.101* 45% 6.67%
28.83% .gtoreq.101* 60% 6.67% 13.83% .gtoreq.101* 0% 10% 70.5%
.gtoreq.83* 15% 10% 55.5% .gtoreq.112* 30% 10% 40.5% .gtoreq.112*
45% 10% 25.5% .gtoreq.112* 60% 10% 10.5% .gtoreq.112* *Blend still
stable when testing terminated
[0077] It is shown in Table 3 that at a particular concentration of
Component B, the maximum length of storage stability could be
increased as the concentration of Component C increased. For
example, at 15% of Component B, the maximum length of storage
stability increased from 9 to 27 to .gtoreq.116 days when the
concentration of Component C was increased from 0% to 3.33% to
6.67%.
[0078] As shown in Table 3, at each level of Component C, the total
concentration of Components B and D remained constant as the level
of Component B was varied with the level of Component C remaining
constant. It can be seen that in the case of the blends that
contained no Component C, as Component B was replaced by Component
D, the maximum length of storage stability reduced. However, in the
case of the blends that did contain Component C, there was more
constancy in the maximum length of storage stability as Component B
was replaced by Component D.
[0079] In Table 4 are set out a number of blends that were tested
at -20.degree. C. Each blend contained 19.5% of Component A. The
fuel used was a 3:1 blend of Component D and Component E. In
respect of each blend is shown the length of time before phase
separation:
TABLE-US-00004 TABLE 4 Maximum length of Component stability
Component B Component C D/E (days) 15% 0% 65.5% 9 30% 0% 50.5% 9
45% 0% 35.5% 15 60% 0% 20.5% .gtoreq.103* 15% 3.33% 62.17% 27 22.5%
3.33% 54.67% .gtoreq.62* 30% 3.33% 47.17% .gtoreq.100* 45% 3.33%
32.17% .gtoreq.100* 60% 3.33% 17.17% .gtoreq.100* 0% 6.67% 73.8% 14
15% 6.67% 58.83% .gtoreq.116* 30% 6.67% 43.83% .gtoreq.101* 45%
6.67% 28.83% .gtoreq.101* 60% 6.67% 13.83% .gtoreq.101* 0% 10%
70.5% .gtoreq.62* 15% 10% 55.5% .gtoreq.118* 30% 10% 40.5%
.gtoreq.103* 45% 10% 25.5% .gtoreq.103* 60% 10% 10.5% .gtoreq.103*
*Blend still stable when testing terminated
[0080] It is shown in Table 4 that at a particular concentration of
Component B, the maximum length of storage stability could be
increased as the concentration of Component C increased. For
example, at 15% of Component B, the maximum length of storage
stability increased from 9 to 27 to .gtoreq.116 days when the
concentration of Component C was increased from 0% to 3.33% to
6.67%.
[0081] As shown in Table 4, at each level of Component C, the total
concentration of Components B and D/E remained constant as the
level of Component B was varied with the level of Component C
remaining constant. It can be seen that in the case of the blends
that contained no Component C, as Component B was replaced by
Component D, the maximum length of storage stability reduced.
However, in the case of the blends that did contain Component C,
there was more constancy in the maximum length of storage stability
as Component B was replaced by Component D.
[0082] In Table 5 are set out a number of blends that were tested
at -20.degree. C. Each blend contained 19.5% of Component A. The
fuel used was a 1:1 blend of Component D and Component E. In
respect of each blend is shown the length of time before phase
separation:
TABLE-US-00005 TABLE 5 Maximum length of Component stability
Component B Component C D/E (days) 15% 0% 65.5% -- 30% 0% 50.5% 9
45% 0% 35.5% 40 60% 0% 20.5% .gtoreq.95* 15% 3.33% 62.17% -- 22.5%
3.33% 54.67% 20 30% 3.33% 47.17% 45 45% 3.33% 32.17% .gtoreq.100*
60% 3.33% 17.17% .gtoreq.100* 0% 6.67% 73.8% 14 15% 6.67% 58.83%
.gtoreq.116* 30% 6.67% 43.83% .gtoreq.101* 45% 6.67% 28.83%
.gtoreq.101* 60% 6.67% 13.83% .gtoreq.101* 0% 10% 70.5% 14 15% 10%
55.5% .gtoreq.118* 30% 10% 40.5% .gtoreq.103* 45% 10% 25.5%
.gtoreq.103* 60% 10% 10.5% .gtoreq.103* *Blend still stable when
testing terminated
[0083] It is shown in Table 5 that at a particular concentration of
Component B, the maximum length of storage stability could be
increased as the concentration of Component C increased. For
example, at 30% of Component B, the maximum length of storage
stability increased from 9 to 45 to .gtoreq.101 days when the
concentration of Component C was increased from 0% to 3.33% to
6.67%.
[0084] As shown in Table 5, at each level of Component C, the total
concentration of Components B and D/E remained constant as the
level of Component B was varied with the level of Component C
remaining constant. It can be seen that in the case of the blends
that contained no Component C, as Component B was replaced by
Component D/E, the maximum length of storage stability reduced.
However, in the case of the blends that did contain Component C,
there was more constancy in the maximum length of storage stability
as Component B was replaced by Component D/E.
[0085] It can also be seen that, taking the figures in Table 3 as
an example, that in the absence of Component C, it was necessary to
include 60% of Component B in order to achieve storage stability
for 60 days. However, when including 3.33%, 6.67% and 10% of
Component C, the concentration of Component B could be reduced to
22.5%, 15% and 0% respectively, with a corresponding increase to
54.67%, 58.83% and 70.5% of Component A respectively, in order to
achieve storage stability for 60 days.
[0086] Thus, the blend compositions of the present invention enable
the aromatic solvent to be replaced, at least in part, by the base
fuel, and yet still achieve a required blend storage stability.
[0087] Although all of the tests in the above Examples were
performed at -20.degree. C., it is stressed that they could also be
performed at other relevant temperatures.
* * * * *