Note: Descriptions are shown in the official language in which they were submitted.
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BIFUNCTIONAL ADDITIVES FOR LIQUID HYDROCARBONS
OBTAINED BY GRAFTING STARTING WITH COPOLYMERS OF
ETHYLENE AND/OR PROPYLENE AND VINYL ESTER
TECHNICAL FIELD
The present invention relates to the synthesis and the use of novel copolymers
based on ethylene and/or propylene and vinyl ester(s) modified by grafting,
effective
for improving both the resistance to cold and the lubricity of liquid
hydrocarbons, in
particular middle distillates originating from the distillation of petroleum
and crude
oils, in particular those with a low sulphur content.
PRIOR ART
For a long time, the oil industry has been developing additives which promote
the filterability of motor fuels at low temperatures: they are copolymers of
ethylene
and vinyl acetate and/or vinyl propionate (EVA or EVP), called CFPP (cold
filter
plugging point) additives. Their role is to modify the crystallization and
more
particularly to limit the size of the paraffin crystals formed at low
temperature, for
example lower than 5 C, with a view to passing through the filters arranged
inside
internal combustion engines or in heating installations. This type of
additives, widely
known to a person skilled in the art, is very often added to the middle
distillates of
standard type, and in particular those used as Diesel fuels or as heating
fuels.
Additional quantities of these additives can be added to the motor fuels sold
in
service stations in particular to meet very cold weather specifications.
Other types of additives such as copolymers of ethylene, vinyl acetate and
branched vinyl ester such as vinyl neodecanoates (VeoVA) having a role on the
CFPP
have been described, in particular in US 2004 /0226216.
In order to improve the resistance to cold, i.e. both the CFPP and the pour
point
of the distillates, additives can be added to these CFPP (EVA or EVP)
additives
which act either alone or in combination with these additives on the pour
point of the
distillates. The prior art copiously describes such combinations of additives
improving both the cold filter plugging point and the pour point of the
hydrocarbon
distillates of standard type at low temperatures.
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Thus, US 3,275,427 describes a middle distillate of distillation cut comprised
between 177 and 400 C containing an additive constituted by 90 to 10% by
weight of
a copolymer of ethylene comprising from 10 to 30% by weight of vinyl acetate
units
of molecular weight comprised between 1,000 and 3,000 and from 10 to 90% by
weight of a lauryl polyacrylate and/or lauryl polymethacrylate with a
molecular mass
by weight varying from 760 to 100,000. It should be noted that these
polyacrylates
improve the filterability temperature determined according to the standard NF
EN 116
without damaging the pour point temperature determined by the standard NF
60105.
For the transport of the crude oils and heavy distillates by pipe, the authors
of
the patent US 3,726,653 were confronted with the problem of the improvement of
pouring in particular at the low temperatures at which these products could
solidify in
the pipes. In order to improve these properties in hydrocarbon compositions
containing paraffins 5 to 20% by weight of which have a boiling point greater
than
350 C and a softening point greater than 35 C, the inventors propose to add to
these
compositions from 10 ppm to 2% by weight of a mixture of a polymer of an
olefinic
ester of carboxylic acids with 3 to 5 carbon atoms with an alcohol with 14 to
30
carbon atoms and with a molecular mass by weight varying from 1,000 to
1,000,000,
with a copolymer of ethylene and vinyl acetate comprising from 1 to 40,
preferably
from 14 to 24 vinyl acetate units of average molecular weight of 20,000 to
60,000.
The molar ratio of the olefinic ester polymer to the copolymer of ethylene and
vinyl
acetate varies from 0.1:1 to 10:1.
In order to control the size of the paraffin crystals present at levels of at
least
3% in middle distillates having a boiling point comprised between 120 C and
480 C,
US 4,153,422 proposes adding to these middle distillates from 10 ppm to 1% by
weight of a mixture of a homopolymer of an olefinic ester of acrylic or
methacrylic
acid comprising an alkyl chain with 14 to 16 carbon atoms and with a molecular
mass
by weight varying from 1,000 to 200,000, with an ethylene and vinyl acetate
copolymer with an average numerical molecular weight lower than 4,000. The
molar
ratio of olefinic ester homopolymer to copolymer of ethylene and vinyl acetate
varies
from 0.1:1 to 20:1.
In addition to the resistance to cold properties, the liquid hydrocarbons, in
particular the diesel fuels, aviation fuels and motor fuels or fuel oils for
domestic
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applications (DFO) must have lubrication abilities for the protection of
pumps,
injection systems and/or all moving parts with which these products come into
contact, for example in an internal combustion engine. With the wish to use
purer and
purer products which are less and less polluting, the oil refining industry is
led to
propose motor fuels or fuel oils with a sulphur content which is more and more
reduced: since 1St January 2005 the sulphur level authorized in motor fuels
within the
European Union has been limited to 50 ppm and it must be less than 10 ppm
starting
from 1St January 2009. Now, as the sulphur compounds are eliminated, a loss of
the
lubricity of these motor fuels is observed. Below a certain level of sulphur-
containing
products, there is even an appreciable appearance of wear phenomena and even
the
breakage of moving parts in pumps and/or injection systems is noticed.
It is therefore necessary to compensate for the lubricating effect of the
sulphur-
containing compounds by the least possible polluting, and if possible non-
polluting,
compounds but having a lubricity sufficient to limit the risks of wear.
In order to resolve this problem, several types of additives have already been
proposed. Thus primarily anti-wear additives, proven in the field of
lubricants, of the
unsaturated fatty acid ester and fatty acid dimer, aliphatic amine, fatty acid
and
diethanolamine ester and long-chain aliphatic monocarboxylic acid type as
described
in patents US 2,257,889, US 4,185,594, US 4,204,481, US 4,208,190, US
4,248,182
are added to the gas oils. Most of these additives have a sufficient
lubricity, but at
excessively high concentrations, which is very detrimental financially.
Moreover, the
additives containing dimer acids, like those containing trimer acids, cannot
be used in
motor fuels supplying vehicles in which the fuel can be in contact with the
lubrication
oil, as the chemical reaction of these acids forms deposits which are
sometimes
insoluble in the oil, and more importantly are incompatible with the
detergents
usually used.
Patent US 4,609,376 recommends the use of anti-wear additives obtained from
mono- and poly-carboxylic acid esters and polyhydroxylated alcohols in motor
fuels
containing alcohols in their composition.
US 2,686,713 recommends the introduction of tall oil up to 60 ppm into diesel
fuels in order to prevent the formation of rust on the metal surfaces in
contact with
these motor fuels.
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Another route chosen is the introduction of vegetable oil esters or the
vegetable
oils themselves into these motor fuels to improve their lubricity or their
anti-friction
qualities. These include the esters derived from rapeseed, flax, soya,
sunflower oils or
the oils themselves (see patents EP 635 558 and EP 605 857). One of the major
drawbacks of these esters is their low lubricity at a concentration of less
than 0.5% by
weight in motor fuels.
In order to improve the lubricity of the gas oils, WO 95/33805 recommends the
introduction of a resistance to cold additive constituted by nitrogen-
containing
additives comprising one or more N-R13 groups in which R13 comprises 12 to 24
carbon atoms, is linear, slightly branched or alicyclic and aromatic, the
nitrogen group
being able to be linked by CO or CO2 and to form carboxylates of amines or
amides.
US 3,667,152 describes the use of tall oil acid (or TOFA, abbreviation of tall
oil
fatty acid) as an anti-wear additive.
EP 915 944 describes anti-friction additives for improving the lubricant
properties of diesel fuels with a low sulphur content, constituted by at least
one
saturated or unsaturated, C 12-C24 monocarboxylic aliphatic hydrocarbon, and
at least
one polycyclic hydrocarbon compound chosen from the group constituted by resin
acids, their derivatives (amine carboxylates, esters and nitriles). These anti-
friction
additives can be used in liquid hydrocarbons in the presence of other
additives, such
as detergents, pro-cetane additives, demulsifiers, anti-corrosion additives,
additives
which improve resistance to cold, odour modifiers, and also known anti-
friction
additives.
WO 94/00536 describes compositions improving the low temperature
properties of fuel oils comprising
a) terpolymers of ethylene - 2 different unsaturated esters and/or
b) mixtures of 2 different copolymers [ethylene- 1 unsaturated ester or an
acrylate] in which the longest ester alkyl chains are C6 to C 13 alkyl chains.
EP 1116780 describes multifunctional additives which improve the cold
properties and lubricity of motor fuels. These additives contain two different
compounds A) 5-95% of an oil-soluble amphiphilic compound and B) 5-95% of a
terpolymer of ethylene - C2-C4 vinyl ester - C8-C15 neocarboxylic vinyl ester
(i.e.
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which contains a tertiary Q. The lubricant properties are provided by the
amphiphilic
compound.
US 5,254,652 describes terpolymers of ethylene - vinyl acetate - C9 or CIO
neoalkanoate vinyl ester which improve the flow properties of motor fuels at
low
5 temperatures.
A need exists to improve not only the resistance to cold (filterability
temperature and pour point) but also the lubricity of the motor fuels based on
liquid
hydrocarbons, in particular low-sulphur or sulphur-free motor fuels.
SUMMARY OF THE INVENTION
The present invention, subject of the present application, relates to
copolymers
which can advantageously be used as bifunctional additives which improve both
the
resistance to cold and the lubricity of the liquid motor fuels in which they
are
incorporated.
Thus the first purpose of the invention relates to the use of these copolymers
as
additives for motor fuel bases, preferably of distillate type for diesel fuels
or for
domestic fuel oils (DFO).
The invention therefore relates to the use as a bifunctional lubricity and
resistance to cold additive for liquid hydrocarbon compositions of at least
one
copolymer comprising:
= units derived from ethylene of formula A - (CH2-CH2)õ1- and/or
propylene of formula A' - ((CH3)CH2-CH2)r2 with nl + n2 = n
ranging from 98 to 643, preferably ranging from 124 to 515; nl
being advantageously equal to n;
= units of formula B: - (CH2-CHOOCR1)m_,,- in which R, represents a
C1-C15 linear or branched alkyl group, preferably methyl, propyl,
and/or a C5 to C 15 branched alkyl group, in which the branching is
situated at any point of the alkyl radical, preferably in position 2 or 3
of the alkyl chain; preferably chosen from the preferred C5-C15
vinyl comonomers, preferably chosen from the pivalate,
isopentanoate, isohexanoate, isononanoate, isodecanoate and/or
isotridecanoate, and advantageously 2-ethyl hexanoate,
neoalkanoates, in particular the neononanoate, neodecanoate and/or
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neoundecanoate; with m ranging from 2 to 105, preferably ranging
from 16 to 71 and x ranging from 0.2 to 105, preferably ranging from
1.6 to 71;
= units of formula C: - (CH2-CHOH)x1- in which xl ranges from 0 to
0.30x, preferably xl = 0;
= units of formula D: - (CH2-CHOOCR2)X2- in which x2 ranges from
0.70x to x, preferably x2 = x, and R2 represents a C8-C24 saturated or
unsaturated, linear or branched, alkyl group, preferably C14-C20 or
also C14 to C18
withx=x1+x2
Preferably, the percentage in moles of units A and/or A' in the copolymer
ranges from 79 to 99% in moles, preferably 86.7 to 90.7% in moles; the
percentage in
moles of units B in the polymer ranges from 0 to 19% in moles, preferably 4.6
to
12% in moles; the% in moles of units C in the polymer is close to 0 to 6.3% in
moles
and advantageously equal to 0% in moles; the percentage in moles of units D in
the
polymer is from 0.1 to 10% in moles, 0.1 to 21 % in moles, preferably 0.93 to
8.6% in
moles.
Preferably, said at least one copolymer is in the form of a concentrated
solution
in a hydrocarbon distillate, preferably at a concentration of more than 50% by
weight,
preferably more than 70% by weight or preferably more than 80% by weight,
preferably 60 to 80% by weight.
According to a preferred embodiment, the hydrocarbon liquid composition is a
hydrocarbon distillate containing from 0 to 5,000 ppm of sulphur, and contains
10 to
5,000 ppm of said at least one copolymer, optionally in a mixture with other
additives such as detergents, dispersants, demulsiffers, anti-foam agents,
biocides,
reodorants, cetane improvers, anti-corrosion agents, friction modifiers,
lubricity,
combustion, cloud point, pour point improvers, anti-sedimentation agents and
conductivity improvers, resistance to cold additives, lubricants.
According to a preferred embodiment, the distillate comprises at least one
hydrocarbon cut originating from the group constituted by the distillates with
a
boiling point comprised between 150 and 450 C, an initial crystallization
temperature ICT greater than or equal to -20 C, preferably greater than or
equal to
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-15 C, preferably comprised between -15 C and + 10 C, comprising distillates
from
direct distillation, distillates from vacuum distillation, hydrotreated
distillates,
distillates originating from catalytic cracking and/or hydrocracking of vacuum
distillates, distillates resulting from ARDS type conversion and/or
visbreaking
processes, distillates originating from the upgrading of Fischer Tropsch cuts,
distillates resulting from the BTL conversion of vegetable and/or animal
biomass,
taken alone or in a mixture, and esters of vegetable and animal oils or their
mixtures.
Preferably, the distillate comprises a C9 to C40 n-paraffin content comprised
between 1 and 40% by mass.
Preferably, said copolymer, as a distillate additive for Diesel fuel comprises
from 0 to 500 ppm of sulphur.
Preferably, said copolymer as a distillate additive for heating fuel oil
comprises
from 0 to 5,000 ppm of sulphur.
According to a preferred embodiment, said copolymer is intended as a
distillate
additive for heavy fuel oil.
The second purpose is to provide a process for the preparation of these novel
polymers via an esterification process of the vinyl ester units which have
been
hydrolyzed previously either in part or in total.
The third purpose of the present invention relates to the novel copolymers of
ethylene and/or propylene and vinyl ester(s) as mentioned above which are
chemically modified by grafting branchings essentially derived from fatty
acid(s) in
particular for their use in motor fuel bases as bifunctional additives.
These motor fuel bases are in general rich in paraffins, weakly aromatic and
as
a result have a low solvent power. The addition of the copolymers according to
the
present invention therefore applies not only to the distillates originating
from the
direct distillation of hydrocarbons originating from crude oils with a very
high
paraffin content but also to the hydrocarbons originating from the heaviest
cuts of
refining operations i.e. cracking, hydrocracking and catalytic cracking
processes and
visbreaking processes or also the synthetic distillates originating from the
conversion
of gas and/or coal such as those originating from the Fischer Tropsch process,
but
also those resulting from the treatment of vegetable and/or animal biomass,
such as in
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particular NexBTL and the distillates containing esters of vegetable and/or
animal
oils, taken alone or in a mixture.
The present invention relates to copolymers comprising:
a) units derived from ethylene of formula A - (CH2-CH2)n1- and/or propylene
of formula A' - ((CH3)CH2-CH2)n2 with nl + n2 = n ranging from 98 to 643,
preferably ranging from 124 to 515; nl being advantageously equal to n;
b) units of formula B: - (CH2-CHOOCRI),,,_X in which R1 represents a C1-C15
linear or branched alkyl group, preferably methyl, ethyl, and/or a C5 to C 15
branched
alkyl group, in which the branching is situated at any point of the alkyl
radical,
preferably in position 2 or 3 of the alkyl chain; among the preferred C5-C15
vinyl
comonomers, there can be mentioned the pivalate, isopentanoate, isohexanoate,
isononanoate, isodecanoate and/or isotridecanoate, and advantageously 2-ethyl
hexanoate, neoalkanoates, in particular the neononanoate, neodecanoate and/or
neoundecanoate; with m ranging from 2 to 105, preferably ranging from 16 to 71
and
x ranging from 0.2 to 105, preferably ranging from 1.6 to 71;
c) units of formula C: - (CH2-CHOH),c1- in which xl ranges from 0 to 0.30x,
preferably xl = 0;
d) units of formula D: - (CH2-CHOOCR2),c2- in which x2 ranges from 0.70x
to x, preferably x2 = x, and R2 represents a C8-C24 saturated or unsaturated,
linear or
branched alkyl group and preferably C14-C20 or also C14 to C18;
with x=x1+X2
Advantageously, the percentage in moles of units A and/or A' in the copolymer
can represent from 79 to 99% in moles, preferably 86.7 to 90.7% in moles;
the percentage in moles of units B can represent from 0 to 19% in moles,
preferably 4.6 to 12% in moles;
the percentage in moles of units C can represent from 0 to 6.3% in moles,
preferably the percentage in moles of units C is close to, or even equal to 0%
in
moles;
the percentage in moles of units D can represent from 0.1 to 21 % in moles,
preferably 0.93 to 8.6% in moles.
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The present invention also relates to the process for the preparation of the
copolymers according to the invention as defined previously; this process
comprises
the following stages:
1) providing a starting copolymer of ethylene and/or propylene and vinyl
ester(s) comprising:
a) units derived from ethylene of formula A - (CH2-CH2)õ 1- and/or propylene
of formula A' - ((CH3)CH2-CH2)i2 with n1 + n2 = n and
b) units of formula B: - (CH2-CHOCORI)õ~- in which R1 is chosen from the
C1-C15 linear or branched alkyl groups, alone or in a mixture, and preferably
comprises the methyl group and/or the ethyl group and/or a C5 to C 15 branched
alkyl
groups, as defined previously;
n and in being as defined previously;
2) hydrolysis reaction, at least partial, of the alkyl esters present in units
B, then
3) esterification reaction, at least partial, and preferably total, of these
hydrolyzed sites by at least one fatty acid of formula R2COOH, R2 being as
defined
previously and/or at least one fatty acid derivative such as an acid
anhydride, acid
halide, preferably acid chloride; the esterification level is preferably
greater than
50%, advantageously greater than 80%, and particularly advantageously equal to
100%.
Another process for the preparation of copolymers consists in carrying out a
transesterification of a copolymer as defined in 1) with an alcohol of type
R2CH2OH;
a transesterification process is for example described in WO 94/00536.
The starting copolymers used in stage 1) are random copolymers comprising:
a) units derived from ethylene of formula A - (CH2-CH2)n and/or from
propylene of formula A' - ((CH3)CH2-CH2)i2 with nl + n2 = n
b) units of formula B: - (CH2-CHOCORI)õj- in which R1 is chosen from C1-C15
linear or branched alkyl group,
n and in being as defined previously
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The copolymers according to the invention have an average numerical molar
weight Mn measured by polystyrene standard calibration GPC, comprised in
general between 4,500 and 20,000 g.mol"I.
The copolymer obtained at the end of stage 2) is obtained by a stage of
partial
5 or total hydrolysis of the ester groups of the starting copolymer of
ethylene and/or
propylene and vinyl ester(s) described above.
In general, the hydrolysis rate can represent from 10 to 100% of the
hydrolysable sites (units B). The hydrolysis can be direct or obtained by
transesterification in an acid or basic medium preferably by basic
methanolysis; the
10 conversion rate of the vinyl ester groups to vinyl alcohol groups is
controlled by the
volume of methanolic soda solution introduced (in the case of
transesterification in a
basic medium). Thus, by varying the hydrolysis rate of stage a) of the
process, the
number of esters grafted on the final copolymer is therefore varied.
The hydrolysis stage 2) is followed by at least one esterification of the
vinyl
alcohol groups formed in the previous stage by one or more fatty acids (stage
3)
preferably converted to acid chlorides, for example using oxalyl chloride, in
order to
improve the esterification yield.
Within the meaning of the present invention, by fatty acid is meant an
aliphatic
carboxylic acid deriving from, or contained in, animal and/or vegetable fats,
oils or
waxes. The natural fatty acids have a saturated or unsaturated, linear,
branched and/or
cyclic carbon-containing chain with 4 to 28 carbon atoms (generally an even
number); preferably, the fatty acids are chosen from the acids having a C8 to
C24 non-
cyclic hydrocarbon chain, alone or in a mixture, such as stearic acid, oleic
acid,
linoleic acid, palmitic acid and/or linolenic acid, and are advantageously
chosen from
the fatty acids having at least one unsaturation.
The scope of the invention would not be exceeded if the esterification stage
was implemented using fatty acids derived from tall oil, which are better
known by
the abbreviation TOFA (tall oil fatty acids). These TOFAs are in general
obtained by
distillation of the tall oil, which is a by-product of the production of pine
wood pulp
by the sulphate process; they comprise a major quantity of fatty acids as
defined
above as well as a minor quantity of resin acids, such as abietic,
dihydroabietic,
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tetrahydroabietic, dehydroabietic, neoabietic, pimaric, levopimaric, and/or
parastrinic
acids, etc. The grafted copolymers obtained can also contain ester functions
of resin
acids formed from the resin acids present in the mixture of acids used.
At the end of stage 3) (esterification of the copolymer originating from stage
2)), a grafted copolymer is obtained which is partially or preferably totally
esterified.
The copolymers according to the invention can be advantageously used as
obtained at the end of stage 3) as additives for liquid hydrocarbons, motor
fuels and
fuel oils.
The copolymers according to the invention have good solubility in the
hydrocarbons of middle distillate type, greater than that of the copolymers of
ethylene
and/or propylene and vinyl ester(s) of the prior art, such as EVA or EVP. This
allows
a significant improvement in the filterability characteristics of the motor
fuels or other
fuels with additives or the blocking tendency characteristics (standard IP
387) of the
motor fuels and other fuels with additives. It is noted that the solubility of
the
copolymers according to the invention is improved with respect to that of the
copolymers of EVA and/ EVP when the FBT (Filter Blocking Tendency) values are
measured; in practice, this better solubility of the compositions of
hydrocarbons
supplemented with the copolymers according to the invention allows blocking of
the
filters (of diameter in general equal to 1.6 m) to be avoided.
The improvement in solubility of the copolymers according to the invention
allows hydrocarbons with additives to be obtained which retain their initial
filterability characteristics at ambient temperature and remain perfectly
filterable in
filtration systems that can be encountered for example in the fuel systems of
engines
and heating installations.
In addition, the lower viscosity of the copolymers in comparison to EVA and/or
EVP makes it possible to achieve concentrated solutions of copolymer(s)
according
to the invention in the hydrocarbons with a reduced level of aromatic solvent
without
detriment to the pumpability and use of these solutions (constraints of
viscosity and
of rheological behaviour in the pumping or injection systems).
The copolymers according to the invention can also be used in the form of a
concentrated solution in a solvent, in general in a hydrocarbon distillate,
preferably at
a concentration of more than 50% by weight, preferably more than 70% by
weight, or
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advantageously at a concentration greater than or equal to 80%; concentrated
solutions in a solvent, in general in a hydrocarbon distillate which are also
preferred
comprise 60 to 80% by weight of copolymer(s) according to the invention.
These copolymers according to the invention or preferably their concentrated
solutions as defined above are in particular used as bifunctional additives:
both as
filterability additives, i.e. additives making it possible to lower the cold
filter
plugging point (CFPP) of compositions based on liquid hydrocarbons and as
additives which improve the lubricity or anti-friction additives for these
compositions
based on liquid hydrocarbons.
The compositions of liquid hydrocarbons in general originate from oil refining
operations, in particular from the direct distillation of hydrocarbons but can
also
originate from thermal cracking, hydrocracking and/or catalytic cracking
processes
and visbreaking processes. They are preferably middle distillates that can be
used as
diesel fuels, domestic heating fuel oils (DFO), kerosene, heavy fuel oils.
With increasing demand for motor fuels, in particular diesel, refiners are
looking to introduce cuts from sources other than petroleum which are more
difficult
to use in these fuels as they can lead to poorer resistance to cold behaviour
in the
latter, by increasing their cold filter plugging point and flow temperature.
Among
these novel sources of distillates, there can in particular be mentioned:
- the heaviest cuts originating from the cracking and visbreaking processes,
with a high concentration of heavy paraffins, comprising more than 18 carbon
atoms,
- the synthetic distillates originating from the conversion of gas such as
those
originating from the Fischer Tropsch process,
- the synthetic distillates resulting from the treatment of biomass of
vegetable
and/or animal origin, such as in particular NexBTL,
- and the oils and/or esters of vegetable or animal oils.
These novel motor fuel bases can be used alone or in a mixture with standard
petroleum middle distillates defined above as motor fuel base and/or domestic
fuel oil
base; they generally comprise long paraffinic chains greater than or equal to
16
carbon atoms.
The liquid hydrocarbon compositions according to the invention comprise a
major proportion of liquid hydrocarbons, preferably of middle distillate type,
with a
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sulphur content preferably lower than 5,000 ppm, preferably lower than 500
ppm,
and more preferably lower than 50 ppm, and a minor proportion comprising at
least
one copolymer according to the invention.
Preferably, in the distillates according to the invention, the major
proportion is
constituted by the distillates with a boiling point comprised between 150 and
450 C,
initial crystallization temperature ICT greater than or equal to -20 C,
preferably
greater than or equal to -15 C, preferably comprised between -15 C and +10
C, and
comprises distillates from direct distillation, distillates from vacuum
distillation,
hydrotreated distillates, distillates originating from catalytic cracking
and/or
hydrocracking of vacuum distillates, distillates resulting from ARDS
(atmospheric
residue desulphuration) type conversion and/or visbreaking processes,
distillates
originating from the upgrading of Fischer Tropsch cuts, distillates resulting
from the
BTL (biomass to liquid) conversion of vegetable and/or animal biomass, taken
alone
or in combination, and esters of vegetable and animal oils or their mixtures.
According to a preferred embodiment of the invention, the distillates
according
to the invention have a C9 to C40 n-paraffin content comprised between 1 and
40%
by mass.
According to another subject, the invention relates to a Diesel fuel
comprising
from 0 to 500 ppm of sulphur and comprising at least one distillate according
to the
invention.
According to another subject, the invention relates to a heating fuel oil
comprising from 0 to 5,000 ppm of sulphur and comprising at least one
distillate
according to the invention. According to another subject, the invention
relates to a
heavy fuel oil comprising at least one distillate according to the invention.
According to a preferred embodiment of the invention, the hydrocarbon
compositions contain from 10 to 5,000 ppm by weight, preferably from 10 to
1,000 ppm of at least one copolymer according to the invention.
Apart from the bifunctional additive or additives according to the invention,
the
hydrocarbon compositions can also contain one or more others which are
different,
chosen from the detergents, anti-corrosion agents, dispersants, demulsifiers,
anti-
foam agents, biocides, reodorants, procetane additives, friction modifiers,
combustion-promoting agents (catalytic combustion and soot promoters), agents
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improving the cloud point, pour point, cold filter plugging point, anti-
sedimentation
agents, anti-wear agents and/or conductivity modifying agents, or even one or
more
other additives which improve the pour point, the cold filter plugging point,
and the
lubricity.
Among these additives, there can be mentioned particularly:
a) procetane additives, in particular (but not limitatively) chosen from alkyl
nitrates, preferably 2-ethyl hexyl nitrate, aroyl peroxides, preferably benzyl
peroxide,
and alkyl peroxides, preferably ter-butyl peroxide;
b) anti-foam additives, in particular (but not limitatively) chosen from
polysiloxanes, oxyalkylated polysiloxanes, and amides of fatty acids
originating from
vegetable or animal oils. Examples of such additives are given in EP 861 882,
EP
663 000, EP 736 590;
c) detergent and/or anti-corrosion additives, in particular (but not
limitatively)
chosen from the group constituted by amines, succinimides,
alkenylsuccinimides,
polyalkylamines, polyalkyl polyamines and polyetheramines. Examples of such
additives are given in EP 938 535;
d) lubricity additive or anti-wear agent, in particular (but not limitatively)
chosen from the group constituted by fatty acids and their ester or amide
derivatives,
in particular glycerol monooleate, and derivatives of mono- and polycyclic
carboxylic
acids. Examples of such additives are given in the following documents: EP 680
506,
EP 860 494, WO 98/04656, EP 915 944, FR2 772 783, FR 2 772 784;
e) cloud point additives, in particular (but not limitatively) chosen from the
group constituted by terpolymers of long chain olefin/(meth)acrylic ester
/maleimide,
and polymers of fumaric/maleic acid esters. Examples of such additives are
given in
EP 71 513, EP 100 248, FR 2 528 051, FR 2 528 051, FR 2 528 423, EP1 12 195,
EP
1 727 58, EP 271 385, EP 291 367;
f) anti-sedimentation or dispersant additives, in particular (but not
limitatively)
chosen from the group constituted by copolymers of (meth)acrylic acid/alkyl
(meth)acrylate amidified by a polyamine, polyamine alkenylsuccinimides,
derivatives
of phthalic acid and a double chain fatty amine; alkyl phenol resins. Examples
of
such additives are given in EP 261 959, EP593 331, EP 674 689, EP 327 423, EP
512
889, EP 832 172, US2005/0223631; US 5 998 530; WO 93/14178.
CA 02709009 2010-06-10
g) multifunctional cold operability additives chosen from the group
constituted
by the polymers based on olefin and alkenyl nitrate as described in EP 573
490.
h) resistance to cold additives such as copolymers of alpha olefin and vinyl
ester(s) such as EVA, EVP, copolymers of ethylene, vinyl acetate and branched
vinyl
5 ester such as vinyl neodecanoates (VEOVA) described in particular in
US 2004/0226216;
i) lubricants such as fatty acids, TOFAs, their derivatives such as esters, in
particular.
These other additives are in general added in a quantity ranging from 10 to
10 1,000 ppm (each).
The bifunctional additives according to the invention can be added to the
hydrocarbon compositions within the refinery, and/or be incorporated
downstream of
the refinery, optionally in a mixture with other additives, in the form of a
package of
additives.
15 Example of the preparation of the grafted polMers:
Starting with the same copolymer of ethylene and vinyl acetate EVA containing
28% by weight of vinyl acetate (denoted EVA 28), i.e. 11.2% in moles, of
average
numerical molar weight = 5,000 g.mol-' measured by polystyrene standard GPC, 4
types of different grafts (units D) denoted DI to D4 were grafted, according
to the
preparation process according to the invention.
D1 is a TOFA (mixture of acids derived from tall oil, containing from 2 to 3%
by weight of resin acids and a mixture of C8 to C24, but mostly C18, fatty
acids; its
concentration of saturated and/or unsaturated C 14 - C 18 fatty acids can vary
from 80
to 90%). The copolymer grafted with D1 can also comprise resin acid ester
functions
formed from the resin acids present in the mixture of acids derived from tall
oil.
D2 to D4 are mixtures of saturated and unsaturated C14 to C18 fatty acids the
molar composition of which in fatty acids is shown in detail in Table 1 below.
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16
Table 1:
Grafted acid C14 C16 C18 C18-1 C18-2 C18-3
D1 - 0.6 1.4 30.8 41.1 10.7
D2 > 86 < 14
D3 1.8 16.6 11.6 24.6 39.3 6.1
D4 1 45 5 38 11 -
The characteristics of the grafted copolymers (% in moles of units A to D are
compiled in Table 2.
Table 2:
Po Starting Type of % in moles % in moles % in moles % in moles % by
ly polymer graft of units A of units B of units C of units D weight
m (nl) (m-x) (x1) (x2) of units D
er
1 EVA28 none 88.8 (130) 11.2 (16) 0(0) 0(0) 0
2 EVA28 Di 88.8 (130) 9.07 (13) 0 (0) 2.13 (3) 15
3 EVA28 D1 88.8 (130) 7.95 (11) 0(0) 3.25 (5) 21.7
4 EVA28 D1 88.8 (130) 6.68 (10) 0 (0) 4.52 (6) 28
5 EVA28 D1 88.8 (130) 5.15 (7) 0 (0) 6.05 (9) 35
7 EVA28 D2 88.8 (130) 7.05 (10) 0 (0) 4.15 (6) 26
8 EVA28 D3 88.8 (130) 7.05 (10) 0 (0) 4.15 (6) 26
9 EVA28 D4 88.8 (130) 4.18 (6) 0 (0) 7.02 (10) 38.5
The cold filter plugging points of 5 GOM middle distillates denoted "a" to "e"
of EN 590 engine gas oil type, the characteristics of which are compiled in
Table 3
below, with one of the copolymers 1 to 9 added at concentrations comprised
between
35 and 700 ppm by weight, were measured.
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17
Table 3 - Characteristics of the gas oils tested
GOM a GOM b GOM c GOM d GOM e
Distillation ASTM D86
T90-T20 112.7 100.5 112 110
MP-T90 18.6 17 23 18
T95 ( C) 353.9 350 356 352
Cloud point ( C) NF EN 23015 -4 -9 -7 -7 -6
CFPP ( C) EN 116 -5 -9 -6 -7 -7
Pour point ( C) NF T 60105 -12 -15 -9 -9 -12
Paraffins (% by mass) Chromatography 19.27 16.1 15.64 18.73
ICT ( C) IP 389 -6 -12.6 -9.5 -12
Sulphur content (ppm) EN ISO 20846 39.8 9.2 48 35 9
The FBT (filter blocking tendency) was also measured according to the
standard IP387 of a solution containing 420 ppm of copolymer 1 to 9 (solution
prepared from a stock solution with 4% by mass of copolymer) as well as the
lubricity measured under HFRR test conditions (High Frequency Reciprocating
Rig
EN ISO 12156-1 or as described in the article SAE 932692 by J.W. Hadley of the
University of Liverpool) with a copolymer concentration of 210 ppm and/or 420
ppm
respectively. The test involves jointly subjecting a steel sphere in contact
with a
stationary metal plate to a pressure corresponding to a weight of 200g and an
alternating movement of 1 mm at a frequency of 50 Hz. The lubricity is
expressed by
the average value of the diameters of the wear scar of the sphere on the
plate. A small
diameter (generally less than 400 m) reflects good lubricity; and conversely,
a large
wear diameter (greater than 400 m) reflects a lubricity which is all the more
insufficient, the greater the diameter.
The results are compiled in Table 4 below.
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18
Table 4:
Poly Dis CFPP CFPP CFPP CFPP CFPP CFPP FBT HFRR HFRR
mer till (35 (70 (140 (210 (350 (700 at 420 AT = 1.4 AT = 1.4
ate ppm) ppm) ppm) ppm) ppm) ppm) ppm ( m) ( m)
( C) ( C) ( C) ( C) ( C) ( C) at 210 at 420
ppm ppm
1 a -8 -13 -15 4.4 556
2 a -9 -16 -15 1.69 415
3 a 1.06
4 a -13 -15 -14 1.01 407
a -13 -16 -15 1.07 531 513
7 a -12 -14 -14
8 a -9 -10 -13
9 a -8 -15 -12 1.04
1 b -10 -12 -13
3 b -11 -13 -13
4 b -12 -13 -20
5 b -12 -13 -24
1 c -10 -12 -15
3 c -15 -16
4 c -15 -18 -17
5 c -16 -19 -18
1 d -15 -17
5 d -18 -21
1 e -13 -17 -19 549
3 e -14 -19 562
4 e -15 -18 395
5 e -15 -20 -20 570
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19
The lubricities (HFRR WS 1.4) of the GOM middle distillate denoted "a " with
variables quantities ranging from 0 to 84 ppm of D1 alone, of copolymer 2, 4
or 5
alone or of a mixture of copolymer 2, 4 or 5 and D 1 added to it are compared.
The results are given in Table 5 below.
TABLE 5
Copolymer No. - 2 4 5 - 2 - 4 -
D1 alone introduced into 0 0 0 0 34 34 60 60 84
GOM a
(ppm by mass)
copolymer i in 0 210 210 210 0 210 0 210 0
GOM a
(ppm by mass)
HFRR WS 1.4 497 415 407 513 455 465 366 409 349
( m)
The lubricities (WS 1.4) of the GOM middle distillate denoted "e", which is
more "severe" than GOM denoted " a ", with variable quantities ranging from 0
to
200 ppm of D 1 alone, or of one of the copolymers 2 to 5 alone or of a mixture
of a
copolymer 2 to 5 and D1 added to it are compared. In order to avoid any change
in
the samples during storage and preparation operations, the grafted polymer
solutions
are stabilized with an antioxidant, butylated hydroxytoluene or 2,6-di-tert-
butyl-4-
methylphenol (BHT) at a concentration of 0.05% to 0.1% with respect to Dl.
The results are compiled in Table 6 below.
Table 6:
Copolymer No. - 2 3 - 4 5 5 -
Total quantity of free D1 0 63 90 100 118 150 150 200
in GOM e
(ppm by mass)
D 1 alone introduced into No No No Yes No No Yes Yes
GOM e
Copolymer i in No Yes Yes No Yes Yes Yes No
GOM e
HFRR WS 1.4 658 549 562 505 395 465 570 392
( m)
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Table 7:
Dl (ppm) Total additives WS1.4
(ppm by ( m)
mass )
GOM e + D1 0 0 658
(comparative)
100 100 505
150 150 423
200 200 392
250 250 368
GOM e + copolymer 4 + D1 0 0 658
115 330 424
135 350 401
160 375 301
185 400 312
248 450 306
285 500 327
GOM e + copolymer 4 0 0 658
85 300 577
118 420 395
150 532 297
185 656 266
