U.S. patent application number 10/459841 was filed with the patent office on 2004-12-16 for aviation fuel cold flow additives and compositions.
This patent application is currently assigned to General Electric Company. Invention is credited to Carey, William S., Deng, Fang, Eldin, Sherif, Goliaszewski, Alan E..
Application Number | 20040250467 10/459841 |
Document ID | / |
Family ID | 33510882 |
Filed Date | 2004-12-16 |
United States Patent
Application |
20040250467 |
Kind Code |
A1 |
Deng, Fang ; et al. |
December 16, 2004 |
Aviation fuel cold flow additives and compositions
Abstract
Aviation fuel, such as jet fuel, blends and methods for
improving cold flow properties of such fuels at extremely low
temperatures are disclosed. Cold flow properties of, for example,
JP-8+100 jet fuel, are improved by addition to the fuel of a
polymer formed from polymerization of an .alpha.-olefin monomer or
monomers. Demonstratable cold flow improvement of such fuels at
temperatures of about -53.degree. C. and lower is shown.
Inventors: |
Deng, Fang; (Drexel Hill,
PA) ; Carey, William S.; (Wallingford, PA) ;
Eldin, Sherif; (Houston, TX) ; Goliaszewski, Alan
E.; (The Woodlands, TX) |
Correspondence
Address: |
WEGMAN, HESSLER & VANDERBURG
6055 ROCKSIDE WOODS BOULEVARD
SUITE 200
CLEVELAND
OH
44131
US
|
Assignee: |
General Electric Company
3135 Easton Turnpike
Fairfield
CT
06828-0001
|
Family ID: |
33510882 |
Appl. No.: |
10/459841 |
Filed: |
June 12, 2003 |
Current U.S.
Class: |
44/408 ;
585/10 |
Current CPC
Class: |
C10L 1/143 20130101;
C10L 1/1641 20130101; C10L 1/224 20130101 |
Class at
Publication: |
044/408 ;
585/010 |
International
Class: |
C10L 001/18; C10L
001/16; C10L 005/00 |
Claims
What is claimed is:
1. Method of improving the cold flow rate of jet fuel comprising
adding to said jet fuel an effective amount of the purpose of a
cold flow rate enhancement agent (CFREA) comprising a polyolefin
formed by polymerization of an .alpha.-olefin monomer having from
about 6 to about 22 carbon atoms.
2. Method as recited in claim 1 comprising adding from a 1-7,500
mg/L of said CFREA to said jet fuel, based upon 1 liter of said jet
fuel.
3. Method as recited in claim 1 wherein said jet fuel is JP-8 based
jet fuel.
4. Method as recited in claim 1 wherein said .alpha.-olefin is a
member selected from the group consisting of 1-decene, 1-dodecene,
1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene,
1-octadecene, and mixtures thereof.
5. Method as recited in claim 4 wherein said .alpha.-olefin
comprises 1-dodecene.
6. Method as recited in claim 1 further comprising adding, as an
adjuvant treatment to said jet fuel, about 1-7,500 mg/L of an
oil-soluble, polar, nitrogen-containing compound to said jet
fuel.
7. Method as recited in claim 6 wherein said oil-soluble, polar,
nitrogen-containing compound comprises an amine or amide.
8. Method as recited in claim 7 wherein said oil-soluble polar
nitrogen compound comprises a reaction product formed from reaction
of a hydrocarbyl acid having two or more carboxyl groups and a
hydrocarbyl secondary amine followed by neutralization of the
resulting product with a hydrocarbyl primary amine.
9. Method as recited in claim 6 wherein said oil-soluble, polar,
nitrogen-containing compound is benzoic acid, 2-[(bis(hydrogenated
tallow alkyl)amino)carbonyl]-C.sub.16-C.sub.22-tert-alkyl amine
salt.
10. Composition for improving the cold flow rate of jet fuel, said
composition comprising, in an organic solvent medium, (1) a cold
flow rate enhancement agent (CFREA) comprising a poly[olefin]
formed by polymerization of an .alpha.-olefin monomer having from
about 6 to about 22 carbon atoms and (2) an oil-soluble, polar,
nitrogen-containing compound.
11. Composition as recited in claim 10 wherein (1) is present in an
amount of about 0.01-100 moles of (1) per 1 mole of (2).
12. Composition as recited in claim 10 wherein said oil-soluble,
polar nitrogen-containing compound is an amine salt and/or
amide.
13. Composition as recited in claim 12 wherein said oil-soluble,
polar nitrogen-containing compound is a reaction product formed by
reaction of a C.sub.4-C.sub.24 hydrocarbyl acid or anhydride
thereof with a C.sub.4-C.sub.24 hydrocarbyl substituted primary,
secondary and/or tertiary amine.
14. Composition as recited in claim 14 wherein said oil-soluble,
polar nitrogen-containing compound comprises a reaction product
formed from reaction of a hydrocarbyl acid having two or more
carboxyl groups or anhydride thereof and hydrocarbyl secondary
amine followed by neutralization of the resulting product with a
hydrocarbyl primary amine.
15. Composition as recited in claim 10 wherein said oil-soluble,
polar nitrogen compound is benzoic acid, 2-[(bis(hydrogenated
tallow alkyl)amino)carbonyl]-C.sub.16-C.sub.22-tert-alkyl amine
salt.
16. Composition as recited in claim 15 wherein said .alpha.-olefin
is a member selected from the group consisting of 1-decene,
1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene,
1-hexadecene, and 1-octadecene and mixtures thereof.
17. Composition as recited in claim 16 wherein said .alpha.-olefin
comprises 1-dodecene.
Description
FIELD OF THE INVENTION
[0001] The invention pertains to jet fuel blends and methods in
which a cold flow enhancement agent is added to the jet fuel to
improve fuel flow rates and flow characteristics at low fuel
temperatures.
BACKGROUND OF THE INVENTION
[0002] It is important that aviation fuel exhibits a freeze point
that is sufficiently low to allow adequate fuel flow through fuel
system lines and filters to the engine. It is known that fuel
temperature decreases as flight time increases and that longer
duration flights typically require lower freezing point fuels than
do shorter duration flights.
[0003] Additionally, high altitude flights, such as those conducted
under military operational conditions, also require lower freezing
point fuels than do lower altitude conventional flights. Quite
obviously then, there is a need to provide freeze point
depressant/cold flow enhancement aids for aviation fuels,
particularly for jet fuels, which will allow for sufficient fuel
flow to desired combustion locations at the extremely low fuel
temperatures encountered at high altitude and long duration
flights. Publications WO 01/32811 A1 and WO 01/62874 A2 discuss
details of aviation fuels and the need for lowered freeze point
fuel blends.
[0004] One such means of enhancing the cold flow properties of wax
containing hydrocarbon fluids is via chemical treatment. For
example, use of poly-.alpha.-olefin to improve the cold flow
properties of gas oil is taught by El-Gamal et al., J. of Polym.
Sci., 61, pp. 1265-1272 (1966). The use of a low molecular weight
highly branched polymers of normal .alpha.-olefin to improve the
cold flow properties of residual fuel oil is taught in U.S. Pat.
No. 4,022,590.
[0005] WO 01/62874 A2 teaches the use of various chemical additives
to lower the freeze point of aviation fuels. It is further taught
that certain classes of pour point additives known to those skilled
in the art for treating middle distillates, such as heating oils
and diesel fuels, are not necessarily effective in the treatment of
aviation fuel and actually may be detrimental.
SUMMARY OF THE INVENTION
[0006] Methods for improving the cold flow rate of aviation fuels,
and jet fuels in particular, are provided wherein the jet fuel is
blended with a cold flow rate enhancement agent (CFREA). These are
polymers of .alpha.-olefins. Any normal .alpha.-olefin having from
about 6-22 C atoms may be employed in preparing the polymer of
present invention. Exemplary .alpha.-olefin monomers include
1-decene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene,
1-hexadecene, 1-octadecene, mixtures of any of the foregoing and
the like. Preferably, the .alpha.-olefin monomer has 10 to 16
carbon atoms. Most preferred the .alpha.-olefin monomer is
1-dodecene.
[0007] The CFREAs of the invention may be used conjointly with an
adjuvant treatment in the jet fuel. This adjuvant may comprise an
oil-soluble, polar nitrogen-containing amine salt and/or amide.
DETAILED DESCRIPTION
[0008] In accordance with the invention, the CFREA comprises a
polymer obtained by polymerization of an .alpha.-olefin. As stated
above, the .alpha.-olefin preferably has about 10-16 carbon
atoms.
[0009] The polymers of the present invention may be prepared via
methods known to those skilled in the art, for example, see U.S.
Pat. Nos. 2,937,129 and 3,149,178. These polymers can be linear
polymers or highly branched polymers as taught in U.S. Pat. Nos.
4,022,590; 4,265,663; and 4,898,751. These patents are hereby
incorporated herein by reference.
[0010] Preferred polymerized .alpha.-olefins are commercially
available from Petrolite Corporation under the VYBAR.RTM. trade
name. Particularly preferred as a cold flow additive for aviation
fuel is VYBAR.RTM. 825. It is taught in U.S. Pat. No. 4,265,663
that VYBAR.RTM. 825 is prepared in accordance with the procedure of
Example 3 of U.S. Pat. No. 2,937,129.
[0011] As would be understood by one skilled in the art in view of
the present disclosure, it is intended that the aforementioned
polymerization methods do not in any way limit the synthesis of the
polymer of the present invention. Furthermore, it is to be
understood that polymers comprising upward of 10 mole % of a
branched olefin and/or isomerized olefin having from about 6 to 22
carbon atoms are also within the purview of the present
invention.
[0012] The polymers of the present inventions should be added to an
aviation fuel, for which improved cold flow performance is desired,
in an amount effective for the purpose. In a preferred embodiment
of the invention, the aviation fuel is selected from Jet Fuel A,
Jet Fuel A-1, Jet Fuel B, JP-4, JP-8 and JP-8+100. Most preferably
the jet fuel is a JP-8 based fuel such as neat JP-8 or the
formulated JP-8+100.
[0013] Jet Fuel A and Jet Fuel A-1 are kerosene-type fuels with Jet
Fuel B being a "wide cut" fuel. Jet A is used for many domestic
commercial flights in the U.S. Most preferably, the CFREAs of the
invention are used to increase the cold flow characteristics of
military jet fuels such as JP-5, JPTS, JP-7, JP-8, and JP-8+100.
JP-5 is currently used by the U.S. Navy with JP-8 and JP-8+100 used
by the Air Force.
[0014] These fuel types are described in the following Table 1.
1TABLE 1 U.S. Military Jet Fuel Freeze Year Point Intro- .degree.
C. Flash Fuel duced Type Max Point Comments JP-5 1952 Kerosene -46
60 U.S. Navy obsolete JPTS 1956 Kerosene -53 43 High thermal
stability JP-7 1960 Kerosene -43 60 Lower higher thermal stability
JP-8 1979 Kerosene -47 38 U.S. Air Force JP-8 + 100 1998 Kerosene
-47 38 U.S. Air Force contains additives for improved thermal
stability JP = jet propulsion Source: Chevron "Aviation Fuels"
Technical Review.
[0015] The CFREA is preferably added to the jet fuel in an amount
of about 1-7,500 mg/L of the jet fuel. More preferably, the CFREA
is added in an amount of between about 200-5,000 mg/L, most
preferably about 4,000 mg/L. The jet fuel/CFREA blend is capable of
improving the cold flow rate of jet fuel, specifically, JP-8 based
jet fuel, at fuel temperatures on the order of about -53.degree. C.
and below. Experimental results have indicated that the CFREAs when
blended with JP-8 based jet fuel in accordance with the invention
improve cold flow rates of the fuel so that they are, as measured
in accordance with Table 2 and the test system described, on the
order of about 0.50 (g/s) and greater at fuel temperatures of about
-53.degree. C. and lower.
[0016] The polymers of the invention can be employed in combination
with conventional fuel additives such as dispersants, antioxidants,
and metal deactivators. Such additives are known to those skilled
in the art, for example see U.S. Pat. Nos. 5,596,130 and
5,614,081.
[0017] The jet fuel cold flow enhancement agents are preferably
used in combination with an adjuvant component comprising an
oil-soluble polar nitrogen-containing compound. These are set forth
in U.S. Pat. No. 4,211,534 (Feldman) incorporated by reference
herein. Basically, as stated in the '534 specification, these
compounds are oil-soluble amine salts and/or amides that are
generally formed by reaction of at least one molar proportion of
hydrocarbyl acid having 1-4 carboxyl groups or their anhydrides
with a hydrocarbyl substituted primary, secondary, and/or tertiary
amine.
[0018] In the case of polycarboxylic acids, or anhydrides, all of
the acid groups may be converted to amine salts or amides, or part
of the acid groups may be left unreacted.
[0019] The term "hydrocarbyl" as defined in U.S. Pat. No. 4,211,534
includes groups that may be branched or straight chain, saturated
or unsaturated, aliphatic cycloaliphatic, aryl, alkaryl,
substituted derivatives thereof and the like. Typically, these
hydrocarbyl groups will consist of from about 4-24 carbon atoms,
more preferably 10-20 carbon atoms. In general, the resultant
compound should contain sufficient hydrocarbyl content so as to be
soluble in the fuel matrix.
[0020] Exemplary hydrocarbyl substituted acids and anhydrides
include, but are not limited to, hexanoic acid, lauric acid,
palmitic acid, steric acid, behenic acid, benzoic acids,
1,2,4,5-benzenetetracarboxylic dianhydride,
1,2-cyclohexanedicarboxylic anhydride, ethylenediaminetetraacetic
dianhydride, salicylic acid, succinic acid, succinic anhydride,
alkenyl succinic anhydrides, polyisobutenyl succinic anhydrides
(PIBSA), phthalic acids, phthalic anhydride, naphthenic acids,
naphthenic anhydrides, and the like. Particularly preferred is
phthalic anhydride.
[0021] The hydrocarbyl-substituted amines may be primary,
secondary, or tertiary; preferably primary or secondary.
[0022] Exemplary hydrocarbyl substituted primary amines include,
but are not limited to, coco amine, tallow amine, hydrogenated
fatty primary amine, 2-ethylhexylamine, n-dodecyl amine,
C.sub.12-14 or C.sub.16-22 tertiary alkyl primary amines from Rohm
and Haas Company marketed under the trade name Primene.RTM.,
mixtures thereof and the like. Particularly preferred is the
C.sub.16-22 tertiary alkyl primary amine marketed by Rohm and Haas
Company under the trade name Primene.RTM. JM-T.
[0023] Exemplary hydrocarbyl substituted secondary amines include,
but are not limited to, dicocoalkylamine, didecylamine,
dioctadecylamine, ditallowamine, dihydrogenated tallowalkylamine,
mixtures thereof and the like. Particularly preferred is
dihydrogenated tallowalkylamine which is commercially available
from Akzo Nobel Corporation under the trade name Armeen.RTM.
2HT.
[0024] As would be understood by one skilled in the art in view of
the present disclosure, it is intended that the aforementioned
examples do not in any way limit the description of the
nitrogen-containing compounds. Furthermore, it is to be understood
that ester analogs derived from a hydrocarbyl alcohol, and
hydrocarbyl sulfo acid analogs such as those derived from
o-sulphobenzoic acid or its anhydride, are also within the purview
of the present invention.
[0025] An especially preferred group of polar nitrogen-containing
compounds is the mixed amine salt/amides derived from reaction of
hydrocarbyl acid (having two or more carboxyl groups) or its
anhydrides as set forth above with a hydrocarbyl secondary amine.
The resulting intermediate amide acid is then neutralized with a
primary amine.
[0026] Generally, the preferred group of polar nitrogen-containing
compounds can be represented by the formula 1
[0027] wherein Z is a divalent organic radical, R.sub.1 and R.sub.2
and R.sub.3 are independently chosen from C.sub.10-C.sub.40
hydrocarbyl groups. The hydrocarbyl groups include straight or
branched chain, saturated or unsaturated aliphatic,
cyclonaliphatic, aryl or alkylaryl moieties. These hydrocarbyl
groups may contain other groups or atoms such as hydroxy groups,
carbonyl groups, ester groups, oxygen, sulfur, or chlorine groups.
As stated above, the hydrocarbyl groups may be on the order of
C.sub.10-C.sub.40 with the range of C.sub.14-C.sub.24 even more
preferred. The R.sub.1, R.sub.2, and R.sub.3 groupings can also
represent mixtures of different hydrocarbyl groups. Preferably,
R.sub.3.noteq.R.sub.1 or R.sub.2.
[0028] The resulting compound should contain sufficient hydrocarbon
content to be oil-soluble.
[0029] The preferred oil-soluble, polar nitrogen-containing
compound is prepared by initial reaction of a hydrocarbyl acid or
its anhydride and a secondary amine, such as the Armeen.RTM. 2HT.
Then, the resulting mixed amine salt/amide is neutralized with a
primary amine such as the commercially available Primene.RTM. JM-T
product. Approximately equimolar amounts of the reactants are used,
resulting in a mixed substituted amide/amine salt.
[0030] The most preferred polar nitrogen-containing compound is an
oil-soluble mixed amide/amine salt formed via reaction of equimolar
amounts of phthalic anhydride with the secondary amine, Armeen.RTM.
2HT. The product of this reaction is then further reacted with an
equimolar amount of the primary amine, Primene.RTM. JM-T to form
benzoic acid, 2-[(bis(hydrogenated tallow alkyl)amino)
carbonyl]-C.sub.16-C.sub.22 tert-alkyl amine salt having the
structural formula: 2
[0031] wherein R.sub.1 and R.sub.2 are mixtures of C.sub.16 and
C.sub.18 hydrocarbon from the commercially available tallowamine
product, and R.sub.3 is a mixture of C.sub.18-22 hydrocarbons from
the commercially available Primene.RTM. JM-T product.
[0032] The adjuvant nitrogen compounds can be used in amounts
similar to those given above in conjunction with CFREA dosage.
[0033] The invention will be described further in conjunction with
the following examples that are included for illustrative purposes
only and should not be construed to limit the invention.
EXAMPLES
[0034] The poly[.alpha.-olefins] of the invention were dissolved in
Aromatic 100 Solvent available from Exxon that is described as a
light aromatic petroleum solvent comprising trimethylbenzene
isomers, xylene isomers, n-propylbenzene and ethylbenzine. 25 wt %
actives solutions were prepared. JP-8 jet fuel was then treated
with a known amount of the additive solutions and subjected to cold
flow testing. Tests were conducted using a Cold Additive Screening
Test Apparatus (CAST) and a U-2 Wing Simulator Device.
[0035] In general, the CAST apparatus consists of two 500 ml
flasks, one at atmospheric pressure and one sealed, connected via a
1/4' Teflon tube. A known amount of fuel is charged to the flask at
atmospheric pressure and the apparatus is cooled to the desired
test temperature in an environmental chamber. Once cooled to the
desired temperature, vacuum (2" Hg) is applied to the sealed flask.
The effectiveness of an additive is determined by measuring the
time it takes for the fuel to flow to the sealed flask, and the
amount of fuel remaining in the atmospheric flask after the fuel
flow ceases.
[0036] Screening results of the poly[.alpha.-olefins] of the
present invention in the CAST apparatus are provided in Table 2
below. At approximately -53.degree. C. the untreated fuel has
solidified and exhibited 100% hold up and essentially no fuel flow.
Additions of the additive of the present inventions to the fuel
dramatically improved the cold flow properties at approximately
-53.degree. C. as evidenced by a substantial decrease in hold up
and increase in fuel flow. It was further observed that substantial
hold up was not observed until the fuel was cooled to approximately
-55.degree. C.
2TABLE 2 CAST Testing Results in JP-8 Fuel Conc. Fuel Flow Rate
Example CFREA mg/L* Temp .degree. C. Hold Up % g/s Comparative None
NA -53.5 100 NA 1 A 16,000 -53.5 5 0.91 2 " " -54.5 6 1.60 3 " "
-55.1 18 1.22 4 " " -56.2 49 0.78 5 " " -57.2 65 0.53 6 " " -52.9 6
1.71 A = VYBAR .RTM. 825 poly[.alpha.-olefin] *25 wt % actives
solution
[0037] Description of the U-2 Wing Simulator Device is provided by
Ervin, J. S. et al., "Investigation of the Use of JP-8+100 with
Cold Flow Enhancer Additives as a Low-Cost Replacement for JPTS",
Energy & Fuels 13, 1246-1251 (1991). Screening results for the
poly[.alpha.-olefins] of the present invention in the U-2 Wing
Simulator Device is summarized in Table 3 below. At approximately
-53.degree. C. the untreated fuel exhibited significant hold up.
Addition of the additive of the present invention to the fuel
dramatically improved the cold flow properties at approximately
-53.degree. C. as evidenced by a substantial decrease in hold
up.
3TABLE 3 U-2 Wing Simulator Testing Result in JP-8 Fuel Tank
Initial Final Conc. Temp Weight Weight Hold up Example CFREA
(mg/L)* (.degree. C.) (lbs) (lbs) (%) Comparative None NA -49 196.5
192.0 2 Comparative None NA -52 198.0 107.2 46 7 A 16,000 -53 197.5
186.0 6 8 A 16,000 -55 197.7 152.5 23 9 A 16,000 -57 201.1 114.4 43
A = VYBAR .RTM. 825 poly[.alpha.-olefin] *25 wt % actives
solution
[0038] Additional tests were conducted on the CAST apparatus using
the poly[.alpha.-olefin] by itself and in conjunction with an
adjuvant treatment comprising the preferred oil-soluble, polar
nitrogenous compound, as set forth above. Results are shown in
Table 4 below. It was observed under certain conditions; e.g.,
Example 16, the performance of the blend exhibited better
performance than the individual components on an equal dosage basis
at comparable temperatures.
[0039] Additive B
Preparation of Benzoic Acid, 2-[(bis(hydrogenated tallow
alkyl)amino)carbonyl]-C.sub.16-22-tert-alkyl amine Salt
[0040] To a four-necked reaction flask equipped with a mechanical
overhead stirrer, thermocouple, reflux condenser, nitrogen sparge
tube, addition port with septum and a heating mantle was added
phthalic anhydride (99%, 5.0 g 0.03342 mole) and Armeen.RTM. 2HT
(17.0 g, 0.03342 mole amine). The resulting wax mixture was then
heated to 90.degree. C. under nitrogen with mixing and held for
four hours. Primene.RTM. JM-T (10.9 g, 0.03342 mole amine) was then
added to the reactor at 90.degree. C. over an eight-hour period,
after which the batch was maintained at 90.degree. C. for an
additional four hours before cooling to room temperature to yield a
wax like material. This wax was then diluted in Aromatic 100 to
yield a 25 wt % solution of the nitrogen-containing compound.
[0041] Additive C
Preparation of Benzoic Acid,
2-[(bis(dodecyl)amino)carbonyl]-C.sub.16-22-t- ert-alkyl amine
Salt
[0042] As in the preparation of Additive B except didocylamine was
substituted for Armeen.RTM. 2HT on an equal molar basis.
4TABLE 4 CAST Studies in JP-8 Fuel Fuel Additive Conc. Temp Hold up
Flow Rate Example Additive 1 Additive 2 Ratio (mg/L)* (.degree. C.)
(%) (g/s) Comparative None None -- -- -53.5 100 N/A 10 A -- --
6,000 -52.9 6 1.71 11 A -- -- 16,000 -53.5 5 0.91 12 A -- -- 16,000
-55.1 18 1.22 13 A -- -- 16,000 -56.4 56 0.76 14 A -- -- 16,000
-57.2 65 0.53 -- -- B -- 6,000 -53.0 10 0.68 -- -- B -- 16,000
-53.3 9 0.93 15 A B 50/50 6,000 -53.3 36 1.09 -- -- C -- 16,000
-54.5 70 0.26 16 A C 50/50 16,000 -55.1 9 1.00 A = VYBAR .RTM. 825
poly[.alpha.-olefin] B = Benzoic acid, 2-[(bis(hydrogenated tallow
alkyl)amino)carbonyl]-C.sub.16-C.sub.22-tert-- alkyl amine salt C =
Benzoic acid, 2-[(bis(dodecyl)amino)carbonyl]-
-C.sub.16-C.sub.22-tert-alky 1 amine salt *25 wt % actives
solution
[0043] Low temperature viscosity studies of the treated fuel were
carried out using a scanning Brookfield Viscometer in the
temperature range of -5.degree. C. to 60.degree. C. as described by
S. Zabarnich and M. Vangsness, Petroleum Chemistry Division
Preprints 2002, 47(3), pp.243-246 (2002). The results of this
testing are given in Table 5. The knee temperature is defined as
the temperature at which a rapid viscosity increase occurs due to
crystal formation. It is desirable to have the "knee temperature"
for a treated fuel to be shifted to a lower temperature relative to
the neat fuel. It is also highly desirable to minimize the rate of
viscosity increase as the fuel is cooled below the knee
temperature.
5TABLE 5 Low Temperature Viscosity Results - Knee Temperature in
JP-8 Fuel Additive Conc. Knee Example Additive 1 Additive 2 Ratio
(mg/L)* Temp .degree. C. Comparative None None -- -- -52.0 A 6,000
-53.9 17 A -- -- 16,000 -55.7 -- -- B -- 16,000 -54.0 18 A B 50/50
8,000 -55.3 19 A B 50/50 16,000 -56.5 A and B = same as in defined
Table 4 *25 wt % actives solution
[0044] When the poly[.alpha.-olefin] CFREAs of the invention are
conjointly used with an oil-soluble, polar nitrogenous adjuvant,
both compounds can be provided in a convenient one drum approach,
dissolved in a suitable organic solvent such as toluene, kerosene,
HAN or the like. The polymeric CFREA is present in such
compositions in a molar amount of about 0.01-100 moles CFREA to
about 1 mole of the adjuvant. At present, it is preferred to use as
the polymeric CFREA, VYBAR.RTM. 825, in conjunction with benzoic
acid, 2-[(bis(hydrogenated tallow
alkyl)amino)carbonyl]-C.sub.16-C.sub.22-tert-alkyl amine salt.
[0045] While the specification above has been drafted to include
the best mode of practicing the invention as required by the patent
statutes, the invention is not to be limited to that best mode or
to other specific embodiments set forth in the specification. The
breadth of the invention is to be measured only by the literal and
equivalents constructions applied to the appended claims.
* * * * *