U.S. patent application number 10/513456 was filed with the patent office on 2005-10-13 for additive for improving the thermal stability of hydrocarbon compositions.
Invention is credited to Bernasconi, Christian, Eydoux, Frank, Vuillet, Celine.
Application Number | 20050223627 10/513456 |
Document ID | / |
Family ID | 29226188 |
Filed Date | 2005-10-13 |
United States Patent
Application |
20050223627 |
Kind Code |
A1 |
Eydoux, Frank ; et
al. |
October 13, 2005 |
Additive for improving the thermal stability of hydrocarbon
compositions
Abstract
The invention relates to the use of at least one additive in
order to increase the thermal stability of a hydrocarbon
composition, said additive being the product of the condensation
reaction between at least one alkenyl succinic or alkyl succinic
anhydride I and a primary amine II. The invention also relates to a
composition comprising the aforementioned additive, an anti-oxidant
and a metal deactivator and to fuels containing same.
Inventors: |
Eydoux, Frank; (Laurent
d'Agny, FR) ; Bernasconi, Christian; (Charly, FR)
; Vuillet, Celine; (Sainte Adresse, FR) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW, LLP
TWO EMBARCADERO CENTER
EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Family ID: |
29226188 |
Appl. No.: |
10/513456 |
Filed: |
November 1, 2004 |
PCT Filed: |
May 2, 2003 |
PCT NO: |
PCT/FR03/01374 |
Current U.S.
Class: |
44/340 |
Current CPC
Class: |
C10L 1/14 20130101; C10L
1/2383 20130101; C10L 1/224 20130101; C10L 10/00 20130101; C10L
1/2283 20130101; C10L 1/1832 20130101; C10L 1/221 20130101; C10L
1/143 20130101 |
Class at
Publication: |
044/340 |
International
Class: |
C10L 001/22 |
Foreign Application Data
Date |
Code |
Application Number |
May 3, 2002 |
FR |
02/05596 |
Claims
1-29. (canceled)
30. Use to increase the thermal stability of a hydrocarbon
composition, of at least one additive which is the product of the
condensation reaction between: (i) at least one alkylsuccinic or
alkenylsuccinic anhydride I of general formula(I): 1in which: R is
an alkyl or alkenyl group comprising 4 to 29 carbon atoms; and (ii)
at least one primary amine II of general formula
NH.sub.2--[(CH.sub.2).sub.m--(CHR.sub.1).sub.n-Z].sub.x-[(CH.sub.-
2).sub.p--(CHR.sub.2).sub.q].sub.y--NHR.sub.3 (II) in which:
R.sub.1 and R.sub.2 are chosen from hydrogen, alkyl groups
comprising 1 to 30 carbon atoms, phenyl groups, R.sub.3 is hydrogen
or an alkyl group comprising 1 to 30 carbon atoms or a phenyl group
or an alkylaromatic group, Z is oxygen or the NH group, x is an
integer from 0 to 5 inclusive, y is an integer from 1 to 5
inclusive, m, n, p and q are integers from 0 to 10 inclusive.
31. Use according to claim 30, in which, in the additive, the
formula of the amine of formula II is
NH.sub.2--[(CH.sub.2).sub.m--NH].sub.x--[(CH.s-
ub.2).sub.p+1].sub.y--NH.sub.2.
32. Use according to claim 30, in which the additive is the product
of the condensation reaction between compounds I and II, used
according to molar ratio I:II comprised between 1:0.2 and 1:1.
33. Use according to claim 30, in which in the additive, the side
chain R is an alkyl or alkenyl group comprising 4 to 24 carbon
atoms.
34. Use according to claim 33, in which the side chain R comprises
12 to 24 carbon atoms.
35. Use according to claims 30, in which in the additive, the side
chain R is an alkenyl group.
36. Use according to claim 30, in which in the additive, the
R.sub.1 and R.sub.2 groups are either hydrogen or alkyl groups
comprising 1 to 10 carbon atoms.
37. Use according to claim 30, in which in the additive, R.sub.3 is
hydrogen or an alkyl group comprising 1 to 20 carbon atoms.
38. Use according to claim 30, in which in the additive, Z is the
NH group.
39. Use according to claims 30, in which in the additive, m, n, p
and q are comprised between 1 and 3 inclusive.
40. Use according to claim 30, in which the additive is used at the
rate of 1 to 200 ppm.
41. Use according to claim 30, in which the additive is used at the
rate of 1 to 100 ppm.
42. Use according to claim 30, in which the additive is used at the
rate of 1 to 50 ppm.
43. Use according to claims 30, in which the additive is used in
combination with an antioxidant and a metal deactivation agent.
44. Method of increasing the thermal stability of aviation fuels
comprising the incorporation into said fuels of an additives as
describe in claim 30.
45. Composition comprising: (a) 1 to 40 parts by weight of at least
one antioxidant; (b) 0.05 to 10 parts by weight of at least one
metal deactivation agent; and (c) 1 to 60 parts by weight of at
least one thermal stability additive which is the product of the
condensation reaction between: (i) at least one alkylsuccinic or
alkenylsuccinic anhydride I of 2general formula(I): in which: R is
an alkyl or alkenyl group comprising 4 to 29 carbon atoms; and (ii)
at least one primary II amine of general formula (II):
NH.sub.2--[(CH.sub.2).sub.m--(CHR.sub.1).s-
ub.n-Z].sub.x-[(CH.sub.2).sub.p--(CHR.sub.2).sub.q].sub.y--NHR.sub.3
in which: R.sub.1 and R.sub.2 are chosen from hydrogen, alkyl
groups comprising 1 to 30 carbon atoms, phenyl groups, R.sub.3 is
hydrogen or an alkyl group comprising 1 to 30 carbon atoms or a
phenyl group or an alkylaromatic group, Z is oxygen or the NH
group, x is an integer from 0 to 5 inclusive, y is an integer from
1 to 5 inclusive, m, n, p and q are integers from 0 to 10
inclusive.
46. Composition according to claim 45, comprising (a) 2 to 40 parts
by weight of antioxidant; (b) 0.1 to 3 parts by weight of metal
deactivation agent; and (c) 2 to 20 parts by weight of thermal
stability additive.
47. Composition according to claim 45, in which the antioxidant is
a sterically hindered phenol.
48. Composition according to claims 45, in which the metal
deactivation agent is a metal chelating agent.
49. Hydrocarbon composition comprising a major part of a
hydrocarbon mixture and the composition according to claim 45, in a
quantity such that the concentration in said composition of thermal
stability additive is 1 to 200 ppm.
50. Hydrocarbon composition comprising a major part of a
hydrocarbon mixture and the composition according to claim 45, in a
quantity such that the concentration in said composition of thermal
stability additive is 1 to 100 ppm.
51. Hydrocarbon composition comprising a major part of a
hydrocarbon mixture and the composition according to claim 45, in a
quantity such that the concentration in said composition of thermal
stability additive is 1 to 50 ppm.
52. Stock solution comprising a solvent and the composition
according to claim 45.
53. Stock solution according to claim 45, in which the solvent is
chosen from aromatic solvents, petroleum cuts, in particular
kerosenes, mineral and/or synthesis oils.
54. Process for the preparation of a composition according to claim
45, by mixing various constituents.
55. Method of increasing the thermal stability of aviation fuels
comprising the incorporation into said fuels of a composition of
additives according to claim 45.
56. Composition comprising: (a) 1 to 40 parts by weight of at least
one antioxidant; (b) 0.05 to 10 parts by weight of at least one
metal deactivation agent; and (c) 1 to 60 parts by weight of at
least one thermal stability additive which is the product of the
condensation reaction between: (i) at least one alkylsuccinic or
alkenylsuccinic anhydride I of general formula(I): 3in which: R is
an alkyl or alkenyl group comprising 4 to 29 carbon atoms; and (ii)
at least one primary II amine of general formula(II):
NH.sub.2--[(CH.sub.2).sub.m--NH].sub.x--[(C-
H.sub.2).sub.p+1].sub.y--NH.sub.2. in which: x is an integer from 0
to 5 inclusive, y is an integer from 1 to 5 inclusive, m, p are
integers from 0 to 10 inclusive.
57. Composition according to claim 56, comprising (a) 2 to 40 parts
by weight of antioxidant; (b) 0.1 to 3 parts by weight of metal
deactivation agent; and (c) 2 to 20 parts by weight of thermal
stability additive
58. Composition according to claim 56, in which the antioxidant is
a sterically hindered phenol.
59. Composition according to claims 56, in which the metal
deactivation agent is a metal chelating agent.
60. Hydrocarbon composition comprising a major part of a
hydrocarbon mixture and the composition according to claim 56, in a
quantity such that the concentration in said composition of thermal
stability additive is 1 to 200 ppm.
61. Hydrocarbon composition comprising a major part of a
hydrocarbon mixture and the composition according to claim 56, in a
quantity such that the concentration in said composition of thermal
stability additive is 1 to 100 ppm.
62. Hydrocarbon composition comprising a major part of a
hydrocarbon mixture and the composition according to claim 56, in a
quantity such that the concentration in said composition of thermal
stability additive is 1 to 50 ppm.
63. Stock solution comprising a solvent and the composition
according to claim 56.
64. Stock solution according to claim 63, in which the solvent is
chosen from aromatic solvents, petroleum cuts, in particular
kerosenes, mineral and/or synthesis oils.
65. Process for the preparation of a composition according to claim
56, by mixing various constituents.
66. Method of increasing the thermal stability of aviation fuels
comprising the incorporation into said fuels of a composition of
additives according to claim 56.
67. Hydrocarbon composition comprising a major part of a
hydrocarbon mixture and: (a) 1 to 1000 ppm, of at least one
antioxidant; (b) 0.1 to 500 ppm, of at least one metal deactivation
agent; and (c) 1 to 200 ppm, of at least one thermal stability
additive which is the product of the condensation reaction between:
(i) at least one alkylsuccinic or alkenylsuccinic anhydride I of
general formula(I): 4in which: R is an alkyl or alkenyl group
comprising 4 to 29 carbon atoms; and (ii) at least one primary II
amine of general formula(II): NH.sub.2--[(CH.sub.2).sub.m--
-(CHR.sub.1).sub.n-Z].sub.x-[(CH.sub.2).sub.p--(CHR.sub.2).sub.q].sub.y--N-
HR.sub.3 in which: R.sub.1 and R.sub.2 are chosen from hydrogen,
alkyl groups comprising 1 to 30 carbon atoms, phenyl groups,
R.sub.3 is hydrogen or an alkyl group comprising 1 to 30 carbon
atoms or a phenyl group or an alkylaromatic group, Z is oxygen or
the NH group, x is an integer from 0 to 5 inclusive, y is an
integer from 1 to 5 inclusive, m, n, p and q are integers from 0 to
10 inclusive.
68. Hydrocarbon composition according to claim 67, comprising a
major part of a hydrocarbon mixture and: (a) 1 to 100 ppm of at
least one antioxidant; (b) 0. 1 to 20 ppm of at least one metal
deactivation agent; and (c) 1 to 100 ppm of at least one thermal
stability additive.
69. Hydrocarbon composition according to claim 67 comprising 1 to
50 ppm of at least one thermal stability additive.
70. Hydrocarbon composition according to claim 67, in which the
antioxidant is a sterically hindered phenol.
71. Hydrocarbon composition according to claim 67, in which the
metal deactivation agent is a metal chelating agent.
72. Hydrocarbon composition according to claim 67, in which the
hydrocarbon mixture is chosen from gasolines, gasoils, kerosenes,
DFOs (Domestic Fuel Oil), heavy fuels, synthesis hydrocarbons such
as those obtained by the oligomerization of olefins or by
Fischer-Tropsch synthesis, biofuels such as vegetable oils and the
esters of vegetable oils, and mixtures of these products.
73. Hydrocarbon composition according to claim 67, in which the
hydrocarbon mixture comprises a middle distillate having a
distillation range comprised between 60 and 350.degree. C.,
preferably between 100 and 300.degree. C.
74. Hydrocarbon composition according to claim 67, which is a fuel,
in particular for aeroplanes.
75. Process for the preparation of a composition according to claim
67, by mixing various constituents.
76. Hydrocarbon composition comprising a major part of a
hydrocarbon mixture and: (a) 1 to 1000 ppm, of at least one
antioxidant; (b) 0.1 to 500 ppm, of at least one metal deactivation
agent; and (c) 1 to 200 ppm, of at least one thermal stability
additive which is the product of the condensation reaction between:
(i) at least one alkylsuccinic or alkenylsuccinic anhydride I of
general formula(I): 5in which: R is an alkyl or alkenyl group
comprising 4 to 29 carbon atoms; and (ii) at least one primary II
amine of general formula(II): NH.sub.2--[(CH.sub.2).sub.m--
-NH].sub.x--[(CH.sub.2).sub.p+1].sub.y--NH.sub.2. in which: x is an
integer from 0 to 5 inclusive, y is an integer from 1 to 5
inclusive, m, p are integers from 0 to 10 inclusive.
77. Hydrocarbon composition according to claim 76, comprising a
major part of a hydrocarbon mixture and: (a) 1 to 100 ppm of at
least one antioxidant; (b) 0.1 to 20 ppm of at least one metal
deactivation agent; and (c) 1 to 100 ppm of at least one thermal
stability additive.
78. Hydrocarbon composition according to claim 76 comprising 1 to
50 ppm of at least one thermal stability additive.
79. Hydrocarbon composition according to claim 76, in which the
antioxidant is a sterically hindered phenol.
80. Hydrocarbon composition according to claim 76, in which the
metal deactivation agent is a metal chelating agent.
81. Hydrocarbon composition according to claim 76, in which the
hydrocarbon mixture is chosen from gasolines, gasoils, kerosenes,
DFOs (Domestic Fuel Oil), heavy fuels, synthesis hydrocarbons such
as those obtained by the oligomerization of olefins or by
Fischer-Tropsch synthesis, biofuels such as vegetable oils and the
esters of vegetable oils, and mixtures of these products.
82. Hydrocarbon composition according to claims 76, in which the
hydrocarbon mixture comprises a middle distillate having a
distillation range comprised between 60 and 350.degree. C.,
preferably between 100 and 300.degree. C.
83. Hydrocarbon composition according to claim 76, which is a fuel,
in particular for aeroplanes.
84. Process for the preparation of a composition according to claim
76, by mixing various constituents.
Description
[0001] A subject of the invention is the use of an additive for
improving the thermal stability of hydrocarbon compositions, as
well as a particular hydrocarbon composition having an improved
thermal stability.
[0002] Fuels intended to function in aeroplane engines (for example
turbojet engines and ramjet engines), usually called kerosene or
jet fuel, are known. They are generally composed of a middle cut
from crude oil distillation, generally containing additives.
[0003] In an aeroplane, the fuel, in addition to its role of
propellant fluid, fulfils other functions. These functions are in
particular:
[0004] coolant fluid by means of exchangers: fuel/hydraulic fluid
(cooling the hydraulic fluid); fuel/oil (cooling the lubrication
oil); fuel/air (cooling the fuel);
[0005] power-transmission fluid: nozzle actuators
[0006] regulation fluid (in particular for the engine).
[0007] Until its injection into the combustion chamber or the
afterburner, the fuel can be subjected to high temperatures, for
example of the order of 200.degree. C., or even higher in contact
with the walls.
[0008] Subjected to these high temperatures, the fuel is subject to
oxidation and thermal decomposition phenomena which cause the
formation of varnishes and gums on the one hand, and particles and
coke on the other. When deposited on fittings which constitute the
fuel system of an aeroplane, these products cause damage and
malfunctions (in particular malfunction of the main injectors,
damage to the combustion chambers, and to the first turbine stage
(excessive temperature), malfunction of the afterburner injectors,
vibrations, loss of efficiency of the heat exchangers, etc.)
Starting problems (in particular from cold), in-flight reignition,
loss of performance can thus occur. These problems also
significantly increase the maintenance costs of aeroplanes.
Moreover, new generation aeroplanes present still further problems
or accentuate the existing problems as they aim to increase the
thrust/weight ratio of the engine and to reduce the fuel
consumption, which involves: an increase in the speed of rotation
of the engine and consequently an increase in the operating
temperature of the engine and of the lubrication oil; a reduction
in the size of the exchangers (dimensions, weight); an increase in
the number of electric and electronic circuits to be cooled and a
reduction in the fuel feed rate (consumption). This therefore
requires an increase in the thermal capacity of the fuel which must
be capable of removing a greater quantity of heat.
[0009] It is therefore sought to improve the thermal stability of
the fuel by incorporation of an additive or a composition of
additives capable of responding to the demands of future aeroplanes
and reducing the maintenance costs while responding to the
technical problems mentioned above. The increase sought is of at
least 100.degree. F., i.e. allowing an increase from 325.degree. F.
(163.degree. C.) to 425.degree. F. (218.degree. C.) for the maximum
temperatures currently encountered and an increase from 400.degree.
F. (204.degree. C.) to 500.degree. F. (259.degree. C.) for the
temperatures of the fuel in contact with the walls.
[0010] To solve these problems, U.S. Pat. No. 5,468,262 describes
an additive for improving the thermal stability of a fuel, this
additive being prepared by (i) reaction of a polyamine, an aldehyde
and a phenol to form a phenol-aldehyde-amine condensate; and (ii)
Mannich's reaction of this condensate with a succinic anhydride
carrying a substituent which is a polyolefin with residual
unsaturation, in particular polyisobutene. This additive can be
schematically represented by the following formula (with PIB for
polyisobutene and PA for polyamine/aldehyde):
[0011] This additive is used, according to this document, in a
proportion comprised between 0.2 and 20% by weight of fuel. Such an
additive poses several specific problems. Firstly, the quantities
required for the additive to be effective are very large, such that
they exceed 2000 ppm, which makes the end fuel very expensive.
Moreover, the presence of a heavy PIB group (with residual
unsaturation) encourages the initiation of deposits on the walls,
which is exactly what one wants to avoid. Finally, such an additive
is surface-active by nature (hydrophobic/hydrophilic duality) and
significant levels of it encourage contamination of fuel by water,
which should be avoided, in particular in fuels for aeroplanes.
[0012] EP-A-0678568 describes an additive reducing the deposits in
aeroplane jet engines. This additive is a derivative of
(thio)-phosphonic acid, used in the example in a quantity of 25
ppm. It is preferably a derivative of polyisobutene thiophosphonic
acid, more particularly its ester with pentaerythritol.
[0013] However, this additive poses several problems. On the one
hand, it is phosphorus-based, which causes atmospheric pollution
linked to the discharge of acid compounds (phosphates, phosphoric
acids) in the combustion gas. On the other hand, it also comprises
a polyisobutene group, and thus poses the same problems as those
already outlined above for the additive which is the subject-matter
of U.S. Pat. No. 5,468,262.
[0014] In order to solve the problems of thermal decomposition and
oxidation of the hydrocarbon flow subjected to high temperatures in
heat exchangers in refineries, U.S. Pat. No. 3,437,583 proposes the
incorporation into the flow of hydrocarbons of an anti-fouling
composition comprising a hindered phenol, a succinimide obtained by
reaction of an acid or succinic anhydride substituted by a
polyamine, and N,N'-disalicylidene-1,2-propane diamine.
[0015] The succinimide is obtained from an anhydride or a succinic
acid substituted by an R'" radical comprising 30 to 200 carbon
atoms. There again, the presence of such a heavy group encourages
the thermal decomposition of the additive, and ultimately proves to
be a precursor of deposits and fouling.
[0016] U.S. Pat. No. 3,776,835 also describes a method of reducing
the rate of fouling on the inside of heat exchangers in which the
hydrocarbon flow circulates. This method consists of adding to the
hydrocarbon flow (a) hydrogen and (b) an agent for inhibiting
deposits, chosen from mono- and poly-amines and -amides comprising
50 carbon atoms. Among the families of chemical compounds capable
of being used as agents for inhibiting deposits there are generally
mentioned succinimides comprising 20 to 200 carbon atoms.
[0017] The use of succinimide-based additives in hydro-carbonated
fuels is moreover known to improve other types of properties, in
particular cold properties.
[0018] Thus Patent Application EP 626.442 deals with problems of
degradation of the cold resistance caused by using ester fuels
produced from the transesterification of animal or vegetable oils
or fats, and recommends the use of such esters combined with a pour
point depressant additive and optionally a carboxylic dispersant
which can be, among others, a compound obtained by reaction of a
substituted succinic anhydride with an amine.
[0019] Long-chain succinimides are largely preferred: the succinic
acid substituent contains a minimum of 12 and preferably 50 carbon
atoms, with a very clear preference for polymers of molecular
weight ranging from 700 to 10,000.
[0020] The succinimide-based additives are used here as dispersant
agents in cold-resistance compositions. In other words their
function is to improve still further the cold resistance of the
mixture by keeping in suspension the hydrocarbon crystals which
form at low temperature to prevent them being deposited. This
antisedimentation function relates only to the properties of
low-temperature fuels, and makes no contribution to thermal
stability at high temperature.
[0021] Similarly, U.S. Pat. No. 3,795,495 recommends the use of
succinimides combined with an alkyl aminoalkyl phosphate to solve
the cold-starting problems of petrol vehicles in the case of the
fuel freezing. Succinimide is the product of condensation of a
succinic anhydride carrying a substituent R comprising 8 to 50
carbon atoms with a polyamine. There again, the succinimides are
used as anti-freezing agents, which implies nothing about their
effectiveness as thermal stability additives at high
temperature.
[0022] A subject of the invention is an additive which allows the
thermal stability of the hydrocarbon compositions, in particular
fuels for aeroplanes, to be improved with a greater effectiveness
than additives already known for this while avoiding the problems
encountered with these additives.
[0023] The present invention therefore proposes the use, to
increase the thermal stability of a hydrocarbon composition, of at
least one additive which is the product of the condensation
reaction between:
[0024] (i) at least one alkylsuccinic or alkenylsuccinic I
anhydride of general formula(I):
[0025] in which:
[0026] R is an alkyl or alkenyl group comprising 4 to 29 carbon
atoms; and
[0027] (ii) at least one primary amine II of general formula
(II):
NH.sub.2--[(CH.sub.2).sub.m--(CHR.sub.1).sub.n-Z].sub.x-[(CH.sub.2).sub.p--
-(CHR.sub.2).sub.q].sub.y--NHR.sub.3
[0028] in which:
[0029] R.sub.1 and R.sub.2 are chosen from hydrogen, alkyl groups
comprising 1 to 30 carbon atoms, phenyl groups,
[0030] R.sub.3 is hydrogen or an alkyl group comprising 1 to 30
carbon atoms or a phenyl group or an alkylaromatic group,
[0031] Z is oxygen or the NH group,
[0032] x is an integer from 0 to 5 inclusive,
[0033] y is an integer from 1 to 5 inclusive,
[0034] m, n, p and q are integers from 0 to 10 inclusive.
[0035] The invention also proposes a composition of additives which
allows the thermal stability of hydrocarbons to be improved. This
composition comprises:
[0036] (a) 1 to 40 parts by weight of at least one antioxidant;
[0037] (b) 0.05 to 10 parts by weight of at least one metal
deactivation agent; and
[0038] (c) 1 to 60 parts by weight of at least one thermal
stability additive which is the product of the condensation
reaction as described above.
[0039] It has been noted surprisingly that the combination of the
three constituents (a), (b) and (c) above, if these constituents
are present in the relative proportions mentioned above, allows the
thermal stability of the hydrocarbon compositions to be
significantly improved. In particular, the abovementioned
composition allows the thermal breakpoint of fuels intended for
aviation to be greatly increased, which allows these fuels to be
used as coolant fluids at higher temperatures or, at the same
temperature, the thermal decomposition of the fuel to be
significantly reduced in the heat exchange zones.
[0040] The invention also provides a hydrocarbon composition
comprising a major part of a hydrocarbon mixture and the
composition of additives above, in a quantity such that the
concentration of said composition as thermal stability additive
ranges from 1 to 200 ppm, preferably 1 to 100 ppm, advantageously 1
to 50 ppm.
[0041] In the present specification, all concentrations expressed
in ppm (parts per million) designate ppm by weight.
[0042] The invention also provides a stock solution comprising a
solvent and the composition of additives above.
[0043] The invention also provides a process for the preparation of
the composition of additives above, by mixing different
constituents.
[0044] The invention finally provides a method for increasing the
thermal stability of fuels for aeroplanes, by incorporating an
additive or a composition of additives as described above into said
fuels.
[0045] The invention will now be described in more detail in the
description which follows.
[0046] The term "alkyl" applies to linear and branched groups.
[0047] By the term "alkylaromatic" is meant groups having an alkyl
chain which carries an aromatic distal substituent, in particular a
phenyl group, the alkyl chain having 1 to 30 carbon atoms.
[0048] The term "hydrocarbon mixture" designates any hydrocarbon
mixture capable of being used as fuel. The hydrocarbon mixture is
advantageously chosen from gasolines, gasoils, kerosenes, DFOs
(Domestic Fuel Oil), heavy fuels, synthesis hydrocarbons such as
those obtained by oligomerization of olefins or by Fischer-Tropsch
synthesis, biofuels such as vegetable oils and the esters of
vegetable oils, and mixtures of these products.
[0049] The hydrocarbon mixture preferably comprises a middle
distillate, i.e. a cut of hydrocarbons the distillation range
(determined according to the ASTM D 86 standard) of which is
comprised between 60 and 350.degree. C., preferably between 100 and
300.degree. C.
[0050] Advantageously, this composition is an aeroplane fuel, for
example kerosene, alone or mixed with a gasoline. There may be
mentioned for example the fuels known to a person skilled in the
art under the following names: JP-4, (MIL-T-5624), JP-5, JP-7, JP-8
(MIL-T-83133), Jet A and JetA-1 (ASTM D 1655). Kerosene can have a
distillation range comprised in the range from 60.degree. C. to
360.degree. C., and for example a starting point of 149-221.degree.
C., 50% point of 221-231.degree. C., 90% point of 260-343.degree.
C. Its API gravity can be 30 to 40. For more details, reference can
be made to the publication "Handbook of Aviation Fuel Properties",
Coordinating Research Council Inc., CRC Report No. 530 (SAE,
Warrendale, USA, 1983). Particularly advantageous aeroplane fuels
are those which conform to the AFQRJOS specification ("Aviation
Fuel Quality Requirements for Jointly Operated Systems") Issue 18
for Jet A-1 of November 1999 (this specification reiterates the
most restrictive criteria of the ASTM D 1655 specification and the
British DEF STAN 91-91 specification).
[0051] The hydrocarbon mixture can have been partly or wholly
subject to a desulphuration and/or denitrogenation and/or
dearomatization treatment. For example, fuels that have been
hydrotreated can be used under more or less severe conditions
(comprising a hydrodesulphuration, a saturation of the aromatic and
olefinic compounds, even a hydro-denitrogenation).
[0052] The hydrocarbon composition advantageously has a sulphur
content less than or equal to 0.5% by weight, preferably less than
or equal to 0.3% by weight. Its content of aromatic compounds is
preferably less than or equal to 25% by volume. It can optionally
contain a substantial quantity of oxygenated compounds such as
ethers, and/or biofuels such as alcohols, or esters of fatty acids
such as for example the methyl ester of rape seed.
[0053] Other hydrocarbon compositions are also suitable; the fuel
can be intended for applications not related to engines, for
example a fuel for ovens, boilers or fuel cells.
[0054] The additive according to the invention, as well as the
composition of additives, allows the thermal stabilization of the
hydrocarbon composition, and therefore responds to the technical
problems outlined above. The additive according to the invention is
generally used in a quantity of 1 to 200 ppm, preferably 1 to 100
ppm, advantageously 1 to 50 ppm.
[0055] The additive according to the invention is prepared by
reacting an anhydride I with an amine II. This reaction is carried
out at a temperature for example of between 120 to 200.degree. C.,
and for a period for example between 1 and 36 hours and preferably
between 5 and 30 hours.
[0056] Condensation of the amines II with the anhydrides I can be
carried out without solvent, but a hydrocarbon solvent with a
boiling point between 70 and 250.degree. C. is preferably used. The
solvent preferably comprises an aromatic or naphthenoaromatic
hydrocarbon, for example: toluene, xylenes, diisopropylbenzene or
also a petroleum cut with a suitable distillation range.
[0057] The additives considered in the invention can in practice be
prepared in the following manner: amine II is gradually introduced
into a reactor containing anhydride I, maintaining the temperature
between 30.degree. C. and 80.degree.. The temperature is then
increased to a value of 120 to 200.degree. C., the volatile
products formed (in particular water) being eliminated either by
entrainment with a stream of inert gas or by azeotropic
distillation with the chosen solvent; the final concentration of
dry material is for example 40 to 70%.
[0058] The preparation methods disclosed for example in the
application WO-A-9413758, to which reference is made and the
content of which is incorporated into the present application, can
be generally applied.
[0059] For the preparation of the additive according to the
invention, an anhydride I in which the side chain R comprises 4 to
24 carbon atoms, even more preferably 12 to 24 carbon atoms, is
preferably used. The side chain R is preferably an alkenyl
group.
[0060] Examples of alkylsuccinic and alkenylsuccinic anhydride are
dodecylsuccinic, dodecenylsuccinic, hexadecylsuccinic,
hexadecenylsuccinic, octadecylsuccinic, octadecenylsuccinic,
eicosylsuccinic and eicosenylsuccinic anhydrides.
[0061] In the additive according to the invention, the amine
corresponds to formula II. The R.sub.1 and R.sub.2 groups are
preferably either hydrogen or alkyl groups comprising 1 to 10
carbon atoms, and/or R.sub.3 is hydrogen or an alkyl group
comprising 1 to 20 carbon atoms, and/or Z is the NH group, and/or
m, n, p and q are comprised between 1 and 3 inclusive. The indices
x and y are preferably comprised between 0 and 2 inclusive.
[0062] Advantageously, amine II corresponds to the following
formula IIa:
NH.sub.2--[(CH.sub.2).sub.m--NH].sub.x--[(CH.sub.2).sub.p+1].sub.y--NH.su-
b.2.
[0063] Non-limitative examples of such amines are: for
non-alkylated amines:
[0064] diethylenetriamine, dipropylenetriamine,
[0065] triethylenetetramine, tetraethylenepentamine and
[0066] tetrapropylenepentamine;
[0067] and for alkylated amines:
[0068] N-alkylethylenediamines, N-alkylpropylenediamines,
[0069] N-alkylbutylenediamines, N-alkyldiethylenetriamines,
[0070] N-alkyldipropylenetriamines, N-alkyldibutylenetriamines,
[0071] N-alkyltriethylenetetramines,
N-alkyltributylenetetramines
[0072] and N-alkyltripropylenetetramines
[0073] having an alkyl radical comprising 1 to 10 carbon atoms.
[0074] For the preparation of the additive, the anhydride I and the
amine II are used in a preferential molar ratio of anhydride:amine
comprised between 1:0.2 and 1:1.
[0075] The molecular mass by weight of the additive can vary
between 300 and 10000 g/mol.
[0076] It is particularly advantageous to use the additive
described above in combination with an antioxidant, in a quantity
relative to the hydrocarbon composition for example comprised
between 1 and 1000 ppm, preferably between 1 and 100 ppm.
Sterically hindered phenols can be used as antioxidants such
as:
[0077] 2,6-di-t-butyl-4-methylphenol (BHT),
[0078] 2,6-di-t-butylphenol,
[0079] 4,4'-methylene bis(2,6-di-t-butyl-phenol),
[0080] 2,6-di-t-butyl-4-dimethylaminomethylphenol,
[0081] 2,4,6-tri-t-butylphenol and
[0082] 2,4-di-methyl-6-t-butylphenol.
[0083] It is likewise advantageous to use a metal deactivation
agent in a quantity relative to the hydrocarbon composition for
example comprised between 0.1 and 500 ppm, preferably between 0.1
and 20 ppm. Metal chelating compounds can be used as deactivation
agents such as for example N,N'-disalicylidene-1,2-propane diamine
of formula:
[0084] Thus, the hydrocarbon composition according to the invention
advantageously comprises:
[0085] (a) 1 to 1000 ppm, and preferably 1 to 100 ppm of at least
one antioxidant;
[0086] (b) 0.1 to 500 ppm, preferably 0.1 to 20 ppm of at least one
metal deactivation agent;
[0087] (c) 1 to 200 ppm, preferably 1 to 100 ppm, advantageously 1
to 50 ppm of the thermal stability additive according to the
invention.
[0088] It can also advantageously comprise other additives chosen
from the additives usually used for the applications considered,
namely for example corrosion-inhibiting additives, anti-freeze
additives, antistatic additives, additives improving the cold
properties, tracer additives, detergent additives, and their
mixtures. The hydrocarbon composition preferably contains at least
one detergent additive chosen from the polyisobuteneamines.
[0089] In particularly advantageous manner, the composition of
additives according to the invention comprises:
[0090] (a) 2 to 40 parts by weight and preferably 4 to 15 parts by
weight of at least one antioxidant;
[0091] (b) 0.1 to 3 parts by weight and preferably 0.5 to 2 parts
by weight of at least one metal deactivation agent; and
[0092] (c) 2 to 20 parts by weight and preferably 3 to 15 parts by
weight of at least one thermal stability additive as described
above.
[0093] With these ranges of proportions relative to the three
constituents (a), (b) and (c), the effectiveness of the composition
of additives is particularly significant, and the increase in
thermal stability is considerably improved.
[0094] In general the additive is supplied in the form of a
concentrated solution ("stock solution") either of thermal
stability additive alone or of the composition of additives (a),
(b) and (c), or the thermal stability additive mixed with any other
standard additive. These "stock solutions" are prepared by
dissolving additives in a solvent which can be chosen from the
aromatic solvents mentioned above, petroleum cuts (in particular
kerosenes), mineral and/or synthesis oils. The "stock solutions"
can contain for example 20 to 60% by weight additives and agents.
According to its concentration, the stock solution is introduced
into the hydrocarbon composition in quantities which can range for
example from 150 ppm weight to 1000 ppm weight.
[0095] The following examples illustrate the invention without
limiting the scope.
[0096] Two additives A and B according to the invention are
prepared, each by condensation of an anhydride I of formula (I)
with a primary amine II of formula (II). Table 1 below details the
formula of each of the reagents I and II:
1TABLE 1 Addi- Formula tive R Z R.sub.3 x y m n and q p A C.sub.24
NH H 1 1 2 0 1 alkenyl group B C.sub.18 NH Mixture of C.sub.14 to 2
0 3 0 1 alkenyl C.sub.18 alkyl groups group
[0097] These additives were prepared in the following manner:
[0098] Additive A:
[0099] a) Synthesis of the Anhydride I:
[0100] 246.8 g of linear C.sub.24 alpha-olefin are heated in a
reactor to 185.degree. C. under nitrogen and under stirring. 91.1 g
of maleic anhydride are then added at a rate such the temperature
of the reaction medium remains at 185.degree. C..+-.2.5.degree. C.
The reaction mixture is stirred for 24 hours at 185.degree. C.,
then cooled down to 60.degree. C. by adding 500 g of xylene
(solvent).
[0101] b) Synthesis of the Additive:
[0102] 161.5 g of diethylenetriamine (DETA) are added to the
mixture from stage (a), maintaining the temperature at
approximately 60.degree. C. Then the water which forms during the
condensation reaction is eliminated together with part of the
solvent, by azeotropic distillation, with a starting distillation
temperature of at least 90.degree. C., and a final distillation
temperature of approximately 150.degree. C.
[0103] The mixture is then cooled down and filtered, and the
condensation product is thus recovered in solution in xylene.
[0104] Additive B:
[0105] a) Synthesis of the Anhydride I:
[0106] 234.3 g of linear C.sub.18 alpha-olefin (n-octadecene) are
heated to 185.degree. C. in a reactor under nitrogen and under
stirring. 91.1 g of maleic anhydride are then added at a rate such
that the temperature of the reaction medium remains at 185.degree.
C..+-.2.5.degree. C. The reaction mixture is stirred for 24 hours
at 185.degree. C., then cooled down to 60.degree. C. by adding 500
g of xylene (solvent).
[0107] b) Synthesis of the Additive:
[0108] 190.6 g of tallow triamine are added to the mixture from
stage (a), maintaining the temperature at approximately 60.degree.
C. Then the water which forms during the condensation reaction is
eliminated together with part of the solvent, by azeotropic
distillation, with a starting distillation temperature of at least
90.degree. C., and a final distillation temperature of
approximately 150.degree. C.
[0109] The mixture is then cooled down and filtered, and the
condensation product is thus recovered in solution in xylene.
[0110] These additives were tested in two JetA-1-type aviation
fuels, the properties of which are given in Table 2 below:
2TABLE 2 Jet no. 1 Jet no. 2 Kerosene cut treated Hydrotreated in a
non-extractive Type kerosene cut Kerox unit Sulphur content 0.0003%
by weight 0.0166% by weight Initial distillation point
145.4.degree. C. 152.9.degree. C. 10% distillation point
161.4.degree. C. 176.1.degree. C. 50% distillation point
189.7.degree. C. 202.0.degree. C. 90% distillation point
238.4.degree. C. 235.5.degree. C. Final distillation point
257.5.degree. C. 249.8.degree. C. Density at 15.degree. C. 816.7
kg/m.sup.3 808.0 kg/m.sup.3
[0111] The sulphur content was determined in accordance with the
ASTM D 1266 standard, the distillation points in accordance with
the ASTM D 86 standard and the density in accordance with the ASTM
D 1298 standard.
[0112] The non-extractive Kerox process converts the mercaptans
contained in a petroleum cut to disulphides.
[0113] These two fuels comply with the AFQRJOS specification
("Aviation Fuel Quality Requirements for Jointly Operated Systems")
Issue 18 for Jet A-1 of November 1999. This specification
reiterates the most restrictive criteria of the ASTM D 1655
specification and the British DEF STAN 91-91 specification.
[0114] The additives were incorporated into the two fuels mixed
with an antioxidant (2,6-di-t-butylphenol) and a metal deactivation
agent (N,N'-disalicylidene-1,2-propane diamine) The thermal
stability breakpoint (here called "breakpoint") of each of the
fuels before and after the addition of additives was determined in
accordance with paragraph X2 of the ASTM D 3241 standard.
[0115] The breakpoints of the fuels to which additives have not
been added are as follows:
[0116] Jet no. 1 295.degree. C.
[0117] Jet no. 2 305.degree. C.
[0118] Tables 3 and 4 below detail the composition of the fuels to
which additives have been added and the results obtained, with
additives A and B respectively.
3TABLE 3 (ADDITIVE A) Fuel Jet no. 1 Jet no. 2 Content of A 25 ppm
25 ppm Content of antioxidant 20 ppm 20 ppm Content of metal
deactivator 2.5 ppm 2.5 ppm Breakpoint 335.degree. C. 335.degree.
C.
[0119]
4TABLE 4 (ADDITIVE B) Fuel Jet no. 1 Jet no. 2 Jet no. 2 Content of
B 25 ppm 8 ppm 25 ppm Content of antioxidant 20 ppm 20 ppm 20 ppm
Content of metal deactivator 2.5 ppm 2.5 ppm 2.5 ppm Breakpoint
>400.degree. C. 345.degree. C. 345.degree. C.
[0120] Tables 3 and 4 above illustrate the excellent performances
of additives according to the invention in terms of improving the
thermal stability of aviation fuels. In fact, additives A and B
generally allow an increase of at least 30.degree. C. in the
thermal stability breakpoint. The increase is often greater, and in
the case of additive B it can even be of the order of 100.degree.
C.
[0121] This increase has been confirmed on very different jet
fuels, which demonstrates the effectiveness of the additives
regardless of the fuel.
* * * * *