EP0722481B1 - Low temperature operability additive compositions of average distillates - Google Patents

Abstract

PCT No. PCT/FR94/01138 Sec. 371 Date Aug. 13, 1996 Sec. 102(e) Date Aug. 13, 1996 PCT Filed Sep. 29, 1994 PCT Pub. No. WO95/09220 PCT Pub. Date Apr. 6, 1995Additive composition enhancing the low temperature operability of average distillates beyond -20 DEG C. comprising at least 40% by weight of a composition consisting of: i) from 60 to 94% by weight of an antisedimentation additive resulting from the reaction of at least one aliphatic dicarboxylic compound and one polyamine of general formula (II) wherein R is a saturated aliphatic radical comprising from 1 to 32 carbon atoms, n is 2-4 and m is 1-4; and ii) 6-40 % by weight of a dispersing-stabilizing additive having a molecular weight varying from 15000 to 50000 resulting from the esterification reaction of a linear alcohol having from 6 to 24 atoms with an organic acid such as maleic acid and its halides, the ester obtained being polymerized with itself or a copolymerizing compound selected from aliphatic dicarboxylic compounds.

Description

The present invention relates to a new composition of additives which improves the cold operability of middle distillates up to temperatures above -20 ° C, and more particularly for diesel fuels and domestic fuel.

This cold operability corresponds to a temperature limit at which middle distillates can be used without clogging problem. It is intermediate between the cloud point temperature (AFNOR NFT 60105 or ASTM D 2500-66) characteristic of the beginning of crystallization of paraffins in the distillate and the pour point of this last (AFNOR NFT60105) or ASTM D 97-66).

It is well known that the crystallization of paraffins is a limiting factor in the use of middle distillates. Also, it is important to prepare diesel fuels adapted to the temperatures at which they will be used in motorized vehicles, i.e. surrounding climate. Generally, cold operability of fuels at -10 ° C is sufficient in many countries industrialized. But in other countries, like countries countries, Canada and the countries of North Asia, we can achieve good fuel usage temperatures below -20 ° C. It is the same for fuels domestic stored outside for homes individuals and buildings.

This adequacy of the cold operability of diesel fuels is important, especially when starting up engine cold. If the paraffins are crystallized at bottom of the tank, they can be driven at startup in the engine and clogging in particular filters and prefilters arranged before the combustion chamber. Likewise for the storage of domestic fuels, paraffins precipitate in bottom of tank and can be entrained and obstruct pipes leading to the boiler. It is obvious that the presence of solids, such as paraffin crystals, prevents normal circulation of the middle distillate.

To improve their circulation either in the engine, either to the boilers, several types of additives have seen the day.

The petroleum industry initially attached to the development of additives promoting filterability of low temperature fuels. These additives, called TLF additives (Filterability Limit Temperature), have the role of limiting the size of the paraffin crystals trained. This type of additive, widely known by humans is currently systematically added to middle distillates.

However, these additives, although regulating the size of paraffinic crystals, can not prevent the sedimentation of the crystals formed, that is to say their agglomeration, especially in the vehicle tank diesels stopped or in fuel tanks domestic workers.

Also, in a second step, the petroleum industry endeavored to develop anti-sedimentation additives, that is to say dispersants, which hold the crystals paraffinics suspended in the middle distillate which prevents them from settling and clumping together (FR 2,531,448). The Applicant has in particular developed such a additive described in French patent application FR-A-92 15358 of December 17, 1992.

However, the combined action of the TLF additives and anti-sedimentation did not improve operability at cold of all middle distillates produced in refineries for all known crude oils.

This is why the petroleum industry has implemented a third type of additive to lower the temperature cold operability of middle distillates whatever they are are above -20 ° C, even if their point temperature cloudiness is greater than -20 ° C (EP 332,000).

The present invention relates to a new composition additives to lower and maintain the cold operability temperature of middle distillates, even after storage, up to temperatures above -20 ° C comprising in particular a third type additive having for action of maintaining a good dispersion of the crystals of paraffins in the middle distillate.

(i) 60%-94% en poids d'un additif d'antisédimentation de masse moléculaire moyenne en poids d'environ 300 à 10.000 résultant de la réaction

(a) d'au moins un composé dicarboxylique aliphatique choisi dans le groupe constitué par les anhydrides maléiques et alkylmaléiques, les anhydrides alkénylsucciniques avec un radical alkényl comprenant de 10 à 32 atomes de carbone, les acides dicarboxyliques et les diesters d'alkyles légers correspondants,

(b) et d'une polyamine comprenant une fonction amine primaire répondant à la formule générale

où R est un radical aliphatique saturé comprenant de 1 à 32 atomes de carbone, R' est choisi dans le groupe constitué par l'atome d'hydrogène et les radicaux aliphatiques saturés comprenant de 1 à 32 atomes de carbone, n est un nombre entier compris entre 2 et 4 et m est un nombre entier compris entre 1 et 4, ladite réaction se produisant après dilution dudit composé dicarboxylique et de ladite polyamine dans un solvant hydrocarboné de point d'ébullition compris entre 70°C et 250°C pour un rapport des concentrations molaires de ladite polyamine sur ledit composé dicarboxylique compris entre 0,3 et 0,8 et à une température comprise entre 120 et 200°C, pendant 1 à 8 heures.

(ii) 6%-40% en poids d'un additif dispersant-stabilisant des cristaux de paraffines de masse moléculaire moyenne en poids entre 15.000 et 50.000 résultant

(A) d'au moins une étape d'estérification d'un alcool linéaire saturé ayant de 6 à 24 atomes de carbone avec un acide organique compris dans le groupe constitué par l'acide acrylique et ses halogènures et,

(B) d'au moins une étape de polymérisation de l'ester résultant de l'estérification avec lui-même ou avec au moins un composé copolymérisant choisi parmi les composés dicarboxyliques du groupe constitué par les anhydrides maléiques, alkylmaléiques et alcénylsucciniques, l'acide acrylique, l'acide fumarique et les esters de ces acides.

The present invention therefore relates to an additive composition for lowering the cold operability temperature of the distillates beyond -20 ° C, characterized in that it consists of 30 to 60% by weight of at least a filterability additive and from 40 to 70% by weight of a combination consisting of:

( i ) 60% -94% by weight of an anti-sedimentation additive with a weight average molecular weight of about 300 to 10,000 resulting from the reaction

(a) at least one aliphatic dicarboxylic compound chosen from the group consisting of maleic and alkylmaleic anhydrides, alkenyl succinic anhydrides with an alkenyl radical comprising from 10 to 32 carbon atoms, the corresponding dicarboxylic acids and light alkyl diesters ,

(b) and of a polyamine comprising a primary amine function corresponding to the general formula

where R is a saturated aliphatic radical comprising from 1 to 32 carbon atoms, R 'is chosen from the group consisting of the hydrogen atom and saturated aliphatic radicals comprising from 1 to 32 carbon atoms, n is an integer between 2 and 4 and m is an integer between 1 and 4, said reaction occurring after dilution of said dicarboxylic compound and said polyamine in a hydrocarbon solvent with a boiling point between 70 ° C and 250 ° C for a ratio of the molar concentrations of said polyamine to said dicarboxylic compound of between 0.3 and 0.8 and at a temperature between 120 and 200 ° C, for 1 to 8 hours.

( ii ) 6% -40% by weight of a dispersing-stabilizing additive for paraffin crystals of average molecular weight between 15,000 and 50,000 resulting

(A) at least one step of esterification of a saturated linear alcohol having from 6 to 24 carbon atoms with an organic acid included in the group consisting of acrylic acid and its halides and,

(B) at least one step of polymerization of the ester resulting from the esterification with itself or with at least one copolymerizing compound chosen from dicarboxylic compounds from the group consisting of maleic, alkylmaleic and alkenyl succinic anhydrides, the acrylic acid, fumaric acid and the esters of these acids.

The polymer thus obtained comprises more than 20% by weight of alkyl chains comprising 12 and 14 atoms of carbon, and finally more than 10% by weight and preferably more of 20% by weight of alkyl chains comprising 16 atoms of carbon and more.

The composition of the present invention improves cold operability of middle distillates since it allows achieve and maintain operating temperatures down to -20 ° C without circulation of the middle distillate influenced by solidification of paraffin crystals by agglomeration favoring blockages.

More specifically, the new composition allows limit the sedimentation of paraffinic crystals and contributes to maintaining the dispersion of the crystals paraffin in middle distillates down to -20 ° C.

These benefits arise from a synergistic effect completely unexpected observed by the plaintiff due to the combination of the anti-sedimentation additive (i) with the dispersing-stabilizing additive for paraffin crystals according to the invention (ii).

In a first embodiment of the invention, the polyamine chosen to prepare the anti-sedimentation additive corresponds to the following general formula (I) R-NH - [- (CH ₂ ) _n -NH-] _m -H in which R is a saturated aliphatic radical comprising from 12 to 32 carbon atoms, n is an integer between 2 and 4 and m is an integer between 1 and 4.

dans laquelle R et R' sont des radicaux alkyles linéaires, identiques ou différents, comprenant de 1 à 24 atomes de carbone, n est un nombre entier compris entre 2 et 4, et m est un nombre entier compris entre 1 et 4.In a second embodiment of the invention, the polyamine chosen to prepare the anti-sedimentation additive corresponds to the following general formula (II)

in which R and R 'are identical or different linear alkyl radicals comprising from 1 to 24 carbon atoms, n is an integer between 2 and 4, and m is an integer between 1 and 4.

The dicarboxylic compound used to make the anti-sedimentation additive is preferably chosen from the group consisting of maleic, alkylmaleic anhydrides, in particular methylmaleic anhydride, and anhydrides alkenyl succinics obtained by the reaction of at least one olefin comprising from 10 to 32 carbon atoms with maleic anhydride.

Preferred as dicarboxylic compound are n-octadecenylsuccinic and dodecenylsuccinic anhydrides.

According to the invention, the dispersing-stabilizing additive is obtained from at least two reactions, one reaction esterification followed by a polymerization reaction.

Saturated linear alcohol participating in the reaction esterification for the formation of this additive is consisting of an alkyl chain comprising from 8 to 22 atoms of carbon.

The preferred organic acid involved in the reaction (A) esterification is acrylic acid.

dans laquelle R₁ et R₂ sont identiques ou différents et correspondent à l'atome d'hydrogène ou un radical aliphatique saturé comprenant de 1 à 30 atomes de carbone, R₃ correspond à un atome d'hydrogène ou un composé dicarboxylique choisi dans le groupe constitué par les anhydrides maléiques, alkylmaléiques ou alcénylsucciniques, l'acide acrylique et l'acide fumarique, p est un nombre entier compris entre 1 et 100, et q est un nombre entier compris entre 1 et 10.According to the invention, the dispersing-stabilizing additive is therefore a polymer of general formula (III):

in which R ₁ and R ₂ are identical or different and correspond to the hydrogen atom or a saturated aliphatic radical comprising from 1 to 30 carbon atoms, R ₃ corresponds to a hydrogen atom or a dicarboxylic compound chosen from the group consisting of maleic, alkylmaleic or alkenylsuccinic anhydrides, acrylic acid and fumaric acid, p is an integer between 1 and 100, and q is an integer between 1 and 10.

dans laquelle R₂ est un radical aliphatique saturé, comprenant de 8 à 22 atomes de carbone, et où q est un nombre entier compris entre 1 et 50.In a first preferred embodiment of the invention, the dispersing-stabilizing additive is a polyacrylate of general formula (IV)

in which R ₂ is a saturated aliphatic radical, comprising from 8 to 22 carbon atoms, and in which q is an integer between 1 and 50.

In a second preferred embodiment of the invention, the additive dispersant-stabilizer is a copolymer.

Said copolymer is constituted for 90 to 99% by weight at least one alkylated acrylate comprising from 8 to 22 atoms of carbon and preferably 8 to 18 carbon atoms per chain alkylated, and from 10 to 1% by weight of at least one compound copolymerizer. In a particular realization of the invention, this said copolymer is constituted for 95 to 99% weight of at least one alkylated acrylate and for 1 to 5% weight of minus one copolymerizing compound.

Said copolymerizing compound is a compound dicarboxylic chosen from the group consisting of maleic, alkylmaleic and alkenylsuccinic anhydrides, and fumaric acid. Preferred copolymerizing compounds are maleic anhydride and fumaric acid.

The new composition according to the present invention is advantageously made up, for 65 to 50% by weight of the combination of at least one anti-sedimentation additive and less a dispersant-stabilizing additive according to the invention and for 35 to 50% by weight of filterability additive. The preferred filterability additive is chosen from the group made up of ethylene vinyl acetate (EVA) copolymers and ethylene vinyl propionate copolymers (EVP).

Another object of the invention is a composition of middle crude oil distillate comprising a proportion major of middle crude oil distillate and a proportion minor of said composition of additives first object of the invention.

In said middle distillate composition, said middle distillate is a hydrocarbon fraction distilled between 150 and 450 ° C, and preferably a distilled diesel cut between 190 and 350 ° C.

In the preferred mode of the distillate composition, the minor proportion of said composition of prime additives object of the invention is between 0.01 and 0.20% by weight of said middle distillate composition.

For the purpose of illustrating the advantages of this invention, examples are given without limitation.

EXAMPLE 1

This example aims to highlight the effect of unexpected synergy of the dispersing-stabilizing additive and the anti-sedimentation additive in the presence of a TLF type filterability.

% paraffine. :

11,84 %

densité à 15°C:

0,836

Distillation ASTM D86 (°C) P.I 159 5% 184 10 % 191 20 % 204 30% 219 40 % 235 50 % 254 60 % 275 70 % 297 80 % 318 90 % 340 95 % 355 P.F. 363 P.I. : point initial P.F. : point final To this end, samples of diesel were prepared from a diesel as defined below and in Table I.

% paraffin. :

11.84%

density at 15 ° C:

0.836

ASTM D86 distillation (° C) PI 159 5% 184 10% 191 20% 204 30% 219 40% 235 50% 254 60% 275 70% 297 80% 318 90% 340 95% 355 PF 363 PI: initial point PF: end point

These gas oils contain different combinations of additives as described in Table II below: ADDITIVE DIESEL COMPOSITION 1 - 0.06% filterability additive (TLF) in diesel 2 - 0.06% composition of additives in diesel * 40% filterability additives (TLF) * 60% anti-sedimentation additive 3 - 0.06% composition of additives in diesel * 40% filterability additive (TLF) * 60% dispersant-stabilizing additive 4 - 0.06% additive composition * 40% filterability additive (TLF) * 36% anti-sedimentation additive * 24% dispersant-stabilizing additive - filterability additive: K5486 marketed by BASF - anti-sedimentation additive: CP9555 marketed by Elf Antar France - dispersant-stabilizing additive according to the invention.

These four additive diesel oils are packaged in four 250 cm ³ test tubes.

These test tubes are hermetically sealed, then left to stand in a cold room at (-20 ° C) for 24 hours. At after 24 hours, the homogeneity of the additive diesel is evaluated by the number of phases observed in each test tube and their quality, then we measure the point temperature of upper and lower phase disorder.

The quality of the upper phase is decisive at look at the anti-sedimentation efficiency of the composition additive. When the upper phase is cloudy, a large proportion of paraffins remained in suspension. When this phase is clear, almost all of the paraffins have sedimented, that is to say agglomerated in the bottom of the test tube.

The quantitative results obtained from the volume% of these different phases and the cloud point temperature difference between the upper phase and the lower phase in the test piece are collated in Table III below: Test tube Number of phases Sediment phase% vol. % Vol. Slightly cloudy phase% vol. Clear or clear phase% vol. Cloud point temperature difference ° C 1 2 22 78 -19 2 2 9 91 -13 3 2 23 77 -21 4 2 4 96 -4

We see that when we add an anti-sedimentation additive with diesel fuel already added to TLF (samples 1 and 2) the homogeneity of the diesel which improves is not improved a decrease in the cloud point difference between the phase upper and lower phase in the test tube.

When adding the dispersant-stabilizing additive according to the invention to the only filterability additive (TLF) in diesel, we do not improve the homogeneity of diesel and the cloud point deviations between the lower phases and remain the same (samples 1 and 3).

However, the combination of the additive anti-sedimentation and dispersant-stabilizing additive with TLF additive greatly improves diesel homogeneity and limits the difference in trouble points between the phase upper and lower (samples 1, 2 and 4).

This underlines the superiority of the invention due essentially the synergistic effect between the anti-sedimentation additive and the dispersant-stabilizing additive.

EXAMPLE II

This example aims to show the universality of the combination of additives according to the invention with a view to lowering cold operability of middle distillates above -20 ° C, whatever their origin.

For the purposes of this example, three gas oils A, B and C additivated by combinations according to the invention are tested as described in Example I. These are characterized by their paraffinic distribution, that is to say by their concentration in paraffins comprising less than 13 carbon atoms (<C ₁₃ ), in paraffins comprising from 13 to 18 carbon atoms (C ₁₃ -C ₁₈ ) and in paraffins comprising from 19 to 23 carbon atoms (C ₁₉ -C ₂₃ ) . This distribution is characteristic of the behavior of diesel fuel when cold, whatever its source.

The paraffin distributions for these three gas oils are given in Table IV below: Diesel % paraffins in diesel % paraffins <C13 % paraffins C13-C18 % paraffins C19-23 AT 10.1 4.95 71.29 23.76 B 10.0 17 74 9 VS 11.84 20.87 50.22 18.91

0.06% by weight of an appropriate composition of additives according to the invention is added to each of these three gas oils, these compositions being described in Table V below: Diesel composition % additive filtration % anti additive sedimentation % additive stabilizing dispersant AT 40 36 24 B 25 65 10 VS 35 55 10

The results of the cold resistance test as described in Example I are given for these three additive diesel oils, according to the invention, in Table VI below, in comparison with these same three diesel oils additive with 0.025% by weight the only filterability additive (TLF): Diesel No. of phases Sediment phase% vol. % Vol. Clear or clear phase% vol. Cloud point temperature difference A + TLF 2 12 88 -22 AT 2 18 82 -7 B + TLF 2 20 80 -20.1 B 2 2 98 -3 C + TLF 2 24 76 -21.8 VS 2 4 96 -4

We note that, whatever the distribution paraffinic of these gas oils, the compositions according to the invention promote cold operability at -20 ° C. characterized by obtaining two phases, one phase sedimented and a cloudy phase, and a temperature difference between the trouble points of the cloudy upper phase and of the sedimented lower phase between 0 and 10 in absolute value.

Claims (19)

1. Additive composition improving the cold operating capability of middle distillates beyond -20°C, characterized in that it includes from 30 to 60% by weight of a filterability additive and from 40% to 70% by weight of a combination consisting of:

   (i) 60% to 94% by weight of an anti-sedimentation additive of mean molar mass by weight of approximately 300 to 10 000 resulting from the reaction

   (a) of at least one aliphatic dicarboxylic compound selected from the group consisting of maleic and alkylmaleic anhydrides, alkenylsuccinic anhydrides having an alkenyl radical comprising from 10 to 32 carbon atoms, dicarboxylic acids and the diesters of light alkyls corresponding thereto,

   (b) and of a polyamine comprising a primary amine function of the general formula

   

   where R is a saturated aliphatic radical comprising from 1 to 32 carbon atoms, R' is selected from the group consisting of the hydrogen atom and the saturated aliphatic radicals comprising from 1 to 32 carbon atoms, n is an integer between 2 and 4 and m is an integer between 1 and 4,
   the said reaction occurring after dilution of the said dicarboxylic compound and of the said polyamine in a hydrocarbonated solvent having a boiling point of between 70°C and 250°C for a ratio of the molar concentrations of the said polyamine to the said dicarboxylic compound of between 0.3 and 0.8 and at a temperature of between 120 and 200°C.

   (ii) 6% to 40% by weight of a dispersant-stabilising additive of mean molar mass by weight of between 15 000 and 50 000 resulting from

   (A) at least one step of esterification of a saturated linear alcohol comprising from 6 to 24 carbon atoms with an organic acid included in the group consisting of acrylic acid and its halides,

   (B) and at least one step of polymerisation of the ester obtained in the preceding step of esterification with itself or with a copolymerising compound selected from the dicarboxylic compounds of the group consisting of maleic, alkylmaleic and alkenylsuccinic anhydrides, acrylic acid, fumaric acid and the esters of these acids,

   the polymer thus obtained comprising more than 20% by weight of alkylated chains comprising 12 and 14 carbon atoms, and finally more than 10% by weight, and preferably more than 20% by weight, of alkylated chains comprising 16 or more carbon atoms.
2. Composition according to Claim 1, characterized in that the polyamine selected for preparing the said anti-sedimentation additive corresponding to the general formula R-NH-[-(CH₂)_n-NH-]_m-H wherein R is a saturated aliphatic radical comprising from 12 to 32 carbon atoms, n is an integer between 2 and 4, and m is an integer between 1 and 4.
3. Composition according to Claim 1, characterized in that the polyamine selected for preparing the said anti-sedimentation additive corresponds to the general formula

   

   wherein R and R' are identical or different linear alkyl radicals, comprising from 1 to 24 carbon atoms, n is an integer between 2 and 4, and m is an integer between 1 and 4.
4. Composition according to one of Claims 1 to 3, characterized in that the dicarboxylic compound selected for preparing the said anti-sedimentation additive is selected from the group consisting of maleic anhydrides, alkylmaleic anhydrides, especially methylmaleic anhydride, and alkenylsuccinic anhydrides obtained by the reaction of at least one olefin comprising from 10 to 32 carbon atoms with maleic anhydride.
5. Composition according to Claim 4, characterized in that the preferred dicarboxylic compounds are n-octadecenylsuccinic anhydride and dodecenylsuccinic anhydride.
6. Composition according to one of Claims 1 to 5, characterized in that the saturated linear alcohol participating in the esterification reaction consists of an alkyl chain comprising from 8 to 22 carbon atoms.
7. Composition according to one of Claims 1 to 6, characterized in that the organic acid intervening in the said esterification reaction (A) is acrylic acid.
8. Composition according to one of Claims 1 to 6, characterized in that the dispersant-stabilising additive is a polymer of the general formula

   

   wherein R₁ and R₂ are identical or different and correspond to a hydrogen atom or a saturated aliphatic radical, comprising from 1 to 30 carbon atoms, R₃ corresponds to a hydrogen atom or a dicarboxylic compound selected from the group consisting of maleic, alkylmaleic and alkenylsuccinic anhydrides, acrylic acid and fumaric acid, p is an integer between 1 and 100 and g is an integer between 1 and 10.
9. Composition according to one of Claims 1 to 8, characterized in that the dispersant-stabilising additive is a polyalkylacrylate of the general formula

   

   wherein R₂ is a saturated aliphatic radical comprising from 8 to 22 carbon atoms, and where g is an integer between 1 and 50.
10. Composition according to one of Claims 1 to 7, characterized in that the dispersant-stabilising additive is a copolymer.
11. Composition according to one of Claims 1 to 7 and 10, characterized in that the copolymer consists to 90 to 99% by weight of at least one alkylated acrylate comprising from 8 to 22 carbon atoms per alkylated chain, and to 10 to 1% by weight of at least one copolymerising compound.
12. Composition according to Claim 10, characterized in that the copolymer consists to 95 to 99% of at least one alkylated acrylate comprising from 8 to 22 carbon atoms per alkylated chain and to 1 to 5% of at least one copolymerising compound selected from the dicarboxylic compounds of the group consisting of maleic, alkylmaleic and alkenylsuccinic anhydrides, and fumaric acid.
13. Composition according to Claim 10, characterized in that the alkylated acrylate units comprise from 8 to 18 carbon atoms per alkylated chain.
14. Composition according to Claim 10, characterized in that the preferred copolymerising compounds are maleic anhydride and fumaric acid.
15. Composition according to one of Claims 1 to 14, characterized in that it comprises from 65 to 50% by weight of the said combination of an anti-sedimentation additive and of a dispersant-stabilising additive, and from 35 to 50% by weight of the filterability additive.
16. Composition according to one of Claims 1 to 15, characterized in that the filterability additive is selected from the group consisting of ethylene-acetate copolymers of vinyl (EVA) and ethylene-propionate copolymers of vinyl (EVP).
17. Middle distillate composition of crude petroleum comprising a major proportion of middle distillate of petroleum and a minor proportion of an additive composition according to one of Claims 1 to 16.
18. Middle distillate composition of petroleum according to Claim 17, characterized in that the said middle distillate is a hydrocarbonated cut distilling between 150 and 450°C and preferably a gas oil cut distilling in a temperature range of between 190 and 350°C.
19. Middle distillate composition of petroleum according to one of Claims 17 and 18, characterized in that the minor proportion of the said additive composition corresponds to 0.01 to 0.20% by weight of the said middle distillate composition.