EP0890633B1 - Use of copolymers of ethylene and unsaturated carboxylic esters in middle distillates to improve cold flow properties - Google Patents

Abstract

Fuel oil contains: (A) a mineral oil having a cloud point of less than -8 degrees C, a boiling point of less than 120 degrees C and a difference between CFPP and PP of less than 10 degrees C; and (B) one or more copolymers contg. bivalent structural units of formula: CH2CH2 (1) and one or more bivalent structural units for formula: CH2CR1CR2 (2) (where, R1 = H or CH3; R2 = COOR3, OR3 or OCOR3; and R3 = 4-30C alkyl); or a unit derived from maleic acid of formula (2a).

Description

The present invention relates to fuel oils, the middle distillates and copolymers of ethylene and Contain esters of unsaturated carboxylic acids, and which show improved cold flow behavior.

Crude oils and middle distillates obtained by distilling crude oils such as gas oil, diesel oil or heating oil, contain different amounts of n-paraffins depending on the origin of the crude oils, crystallize the temperature as platelet-shaped crystals and partially with the inclusion of oil agglomerate. This leads to a deterioration in the flow properties of these oils or Distillates, which, for example, during the extraction, transport, storage and / or use of Mineral oils and mineral oil distillates can occur. With mineral oils this can Crystallization phenomenon during transport through pipelines, especially in winter, leads to deposits the pipe walls, in individual cases, e.g. if a pipeline is at a standstill, even to completely block it to lead. Precipitation of can also occur during the storage and processing of mineral oils Paraffins cause difficulties. So it may be necessary in winter, the Store mineral oils in heated tanks. Mineral oil distillates can result from crystallization Clogging of the filters in diesel engines and combustion plants occur, making them safe Dosing of the fuel is prevented and, if necessary, a complete interruption of the Fuel or heating medium supply occurs.

In addition to the classic methods for removing the crystallized paraffins (thermal, mechanically or with solvents) that only affect the removal of those already formed Related precipitates, chemical additives (so-called Flow improvers or paraffin inhibitors) developed by physical interaction with The failing paraffin crystals cause their shape, size and adhesive properties be modified. The additives act as additional crystal nuclei and partially crystallize with the paraffins, resulting in a larger number of smaller paraffin crystals with altered Crystal form results. Part of the effect of the additives is also by dispersing the Paraffin crystals explained. The modified paraffin crystals are less prone to agglomeration, so that the oils mixed with these additives can still be pumped or processed at temperatures, which are often more than 20 ° C lower than with non-additive oils.

The flow and cold behavior of mineral oils and mineral oil distillates is determined by specifying the pour point (determined according to ISO 3016) and the cold filter plugging point (CFPP; determined according to EN 116) described. Both parameters are measured in ° C.

Typical flow improvers for crude oils and middle distillates are copolymers of ethylene with Carboxylic acid ester of vinyl alcohol. So according to DE-A-11 47 799 petroleum distillate propellant or fuels with a boiling point between about 120 and 400 ° C oil-soluble copolymers from ethylene and vinyl acetate with a molecular weight between about 1,000 and 3,000. Copolymers containing about 60 to 99% by weight of ethylene and about 1 to 40% by weight are preferred. Contain vinyl acetate. They are particularly effective when used in radical polymerization an inert solvent at temperatures of about 70 to 130 ° C and pressures of 35 to 2,100 were manufactured (DE-A-1914 756).

wobei R und R' gleich oder verschieden sind und Wasserstoff oder C₁-C₄-Alkylreste bedeuten (EP-A-0 099 646). Auch Mischpolymerisate aus Ethylen, Alkencarbonsäureester und/oder Vinylester und Vinylketon werden als Stockpunktemiedriger und zur Verbesserung des Fließverhaltens von Rohölen und Mitteldestillaten der Rohöle verwendet (EP-A-0 111 888).In addition to ethylene and vinyl acetate, other polymers used as flow improvers contain, for example, hexene-1 (cf. EP-A-0184 083), diisobutylene (cf. EP-A-0 203 554) or an isoolefin of the formula

wherein R and R 'are the same or different and are hydrogen or C ₁ -C ₄ alkyl radicals (EP-A-0 099 646). Copolymers of ethylene, alkenecarboxylic acid ester and / or vinyl ester and vinyl ketone are also used as pour point depressants and to improve the flow behavior of crude oils and middle distillates of the crude oils (EP-A-0 111 888).

In addition, copolymers based on α, β-unsaturated compounds and Maleic anhydride used as a flow improver.

DE-196 45 603 describes copolymers of 60 to 99 mol% derived from ethylene Structural units and 1 to 40 mol% of structural units that differ from maleic acid, its Derive anhydride or its imides.

DE-1 162 630 discloses copolymers of ethylene and vinyl esters of straight-chain fatty acids 4 to 18 carbon atoms as a pour point reducing additive for distillate fuels of medium size Siedelage such as Hiezöl or diesel oil.

EP-A-0 217 602 discloses ethylene copolymers with vinyl esters bearing C ₁ to C ₁₈ alkyl radicals as flow improvers for mineral oil distillates with boiling ranges (90-20)% below 100 ° C.

EP-A-0 493 769 discloses terpolymers which consist of ethylene, vinyl acetate and neononane or Neodecanoic acid vinyl esters are produced, and their use as additives for Mineratöldestillate.

EP-A-0 746 598 discloses copolymers of ethylene and di-alkyl fumarates mixed with Mineral oils with a cloud point below -10 ° C.

The effectiveness of known additives to improve the properties of Mineral oil fractions include depending on the origin of the mineral oil from which they were obtained and in particular its composition. Additives used to adjust certain Property values of fractions of a crude oil are therefore extremely suitable Distillates of crude oils of other origin lead to completely unsatisfactory results.

In the course of increasing environmental awareness, fuels are now being produced that are used in their Burn cause less environmental pollution. Draw appropriate diesel fuels a very low sulfur content of less than 500 ppm and in particular less than 100 ppm, a low aromatic content and a low density of less than 0.86, in particular less than 0.84 g / ml. They cannot be done with conventional flow improvers or insufficiently additive. The main problems are those for use under arctic conditions produced winter qualities of diesel fuels with their extreme Katte properties, such as a cloud point below -8 ° C and especially below -15 ° C, very much narrow distillation cuts with boiling ranges from 20 to 90 vol .-% less than 120 ° C, in particular less than 100 ° C and sometimes also less than 80 ° C, and a distillation volume of 95% by volume Temperatures below 360 ° C, especially below 350 ° C and especially below 330 ° C. The Cold properties of such distillates can currently only be achieved by adding low-boiling, low-paraffin components, e.g. Kerosene, can be improved satisfactorily.

The composition caused by narrow distillation cuts and low boiling ends is problematic for the response behavior of flow improvers to these oils: These oils have a paraffin distribution with a maximum at around C ₁₂ to C ₁₄ and contain only insignificant amounts of the n-paraffins with hydrocarbon chains that crystallize from conventional grades longer as C ₁₈ . The cloud points and CFPP values are so low, especially in terms of winter qualities, that conventional flow improvers do not respond and the properties of the liquid have to be adjusted by diluting with kerosene.

It was therefore the task of new fuel oils with a compared to the prior art to develop improved flowability in the cold.

Surprisingly, it was found that main chain polymers made of ethylene, the side chains with carry more than 5 carbon atoms, are suitable, the CFPP also in those described above Lower middle distillates. Ethylene / vinyl acetate copolymers with corresponding In contrast, comonomer contents are practically insoluble in hydrocarbons.

A) einem Mineralöl mit einem Schwefelgehalt von weniger als 100 ppm, einem Cloud Point von weniger als -8°C, einem Siedebereich (90-20 %) von weniger als 120°C und einer Differenz zwischen cold filter plugging point (CFPP) und pour point (PP) von weniger als 10°C, und

B) einem Copolymer, enthaltend 85 bis 97 mol-% bivalente Struktureinheiten der Formel

B1) -CH₂-CH₂- und 3 bis 15 mol-% einer oder mehrerer der bivalenten Struktureinheiten B2)

B2) -CH₂-CR¹R²-

worin R¹ Wasserstoff oder Methyl und R² COOR³, OR³ oder OCOR³ bedeuten, wobei R³ für einen Alkylrest mit mindestens 8 und höchstens 24 Kohlenstoffatomen steht, und bis zu 3 mol-% vom Vinylacetat abgeleitete Struktureinheiten oder bis zu 5 mol-% von weiteren Comonomeren abgeleitete Struktureinheiten.The invention relates to fuel oils consisting of

A) a mineral oil with a sulfur content of less than 100 ppm, a cloud point of less than -8 ° C, a boiling range (90-20%) of less than 120 ° C and a difference between cold filter plugging point (CFPP) and pour point (PP) of less than 10 ° C, and

B) a copolymer containing 85 to 97 mol% of bivalent structural units of the formula

B1) -CH ₂ -CH ₂ - and 3 to 15 mol% of one or more of the bivalent structural units B2)

B2) -CH ₂ -CR ¹ R ² -

where R ^{1 is} hydrogen or methyl and R ^{2 is} COOR ³ , OR ³ or OCOR ³ , where R ^{3 is} an alkyl radical having at least 8 and at most 24 carbon atoms, and up to 3 mol% of structural units derived from vinyl acetate or up to 5 mol % of structural units derived from further comonomers.

The cloud point of the mineral oils mentioned under A) is preferably below -15 ° C. The boiling ranges (90-20%) of the distillation cuts are preferably less than 100 ° C., in particular less than 80 ° C. It is preferred to use mineral oils with a 95% distillation point below 360 ° C, especially below 350 ° C, especially below 330 ° C.

R' und R" sind lineare Alkylreste mit zusammen vorzugsweise 5 bis 9, insbesondere 6, 7 oder 8 Kohlenstoffatomen. Der zur Copolymerisation verwendete Vinylester hat demzufolge die Formel (4):

R ^{1 is} preferably hydrogen. R ³ preferably represents a linear or branched C ₈ -C ₁₈ alkyl radical. In a further, particularly preferred embodiment of the invention, R denotes a neoalkyl radical with 7 to 11 carbon atoms, in particular a neoalkyl radical with 8, 9 or 10 carbon atoms. The neoalkyl acids from which the above-mentioned neoalkyl radicals can be derived are described by the formula (3):

R 'and R "are linear alkyl radicals with a total of preferably 5 to 9, in particular 6, 7 or 8, carbon atoms. The vinyl ester used for the copolymerization accordingly has the formula (4):

Other suitable comonomers are those which can be derived from acrylic acid:

Preferred radicals R ³ are, for example, butyl, tert-butyl, pentyl, neopentyl, octyl, 2-ethylhexyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl and behenyl.

The fuel oil compositions according to the invention preferably contain copolymers in which the comonomers B1) with 90 to 96 mol% and the comonomers B2) with 4 to 10 mol% are included.

The copolymers mentioned under B) are as usual by the usual copolymerization for example suspension polymerization, solvent polymerization, gas phase polymerization or high-pressure mass polymerization. The is preferred High pressure bulk polymerization at pressures of preferably 50 to 400, in particular 100 to 300 MPa and temperatures of preferably 50 to 300, in particular 100 to 250 ° C. The reaction of the Monomers are initiated by radical initiators (radical chain initiators). To this Substance classes belong e.g. Oxygen, hydroperoxides, peroxides and azo compounds such as Cumene hydroperoxide, t-butyl hydroperoxide, dilauroyl peroxide, dibenzoyl peroxide, bis (2-ethylhexyl) peroxide carbonate, t-butyl perpivalate, t-butyl permaleinate, t-butyl perbenzoate, dicumyl peroxide, t-Butylcumyl peroxide, di- (t-butyl) peroxide, 2,2'-azobis (2-methylpropanonitrile), 2,2'-azobis (2-methylbutyronitrile). The initiators are used individually or as a mixture of two or more substances Amounts of 0.001 to 20 wt .-%, preferably 0.01 to 10 wt .-%, based on the Monomer mixture used.

The copolymers mentioned under B) preferably have melt viscosities at 140 ° C. of 20 to 10,000 mPas, in particular from 30 to 5000 mPas, especially from 50 to 2000 mPas. The desired Melt viscosity of these copolymers is given the given composition of Monomer mixture by varying the reaction parameters pressure and temperature and possibly by adding moderators. The moderators are hydrogen, saturated or unsaturated hydrocarbon, e.g. Propane, aldehydes, e.g. Propionaldehyde, n-butyraldehyde or isobutyraldehyde, ketones, e.g. Acetone, methyl ethyl ketone, methyl isobutyl ketone, Cyclohexanone or alcohols, e.g. Butanol, proven. Depending on the desired viscosity the moderators are used in amounts of up to 20% by weight, preferably 0.05 to 10% by weight the mixture of monomers applied.

The copolymers mentioned under B) can contain up to 3 mol% of vinyl acetate or up to 5 mol% of more Comonomers included. Such comonomers can, for example, vinyl esters, vinyl ethers, Acrylic acid alkyl esters, methacrylic acid alkyl esters or higher olefins with at least 5 Be carbon atoms. Hexene, 4-methylpentene, octene or are preferred as higher olefins Diisobutylene.

In order to obtain the copolymers mentioned under B), monomer mixtures are used which in addition to ethylene and optionally a moderator 1 to 50% by weight, preferably 3 to 40% by weight Comonomer included. With that deviating from the composition of the copolymer The composition of the monomer mixture is carried by the different ones Polymerization rate of the monomers calculation. The polymers fall as colorless Melt, which solidify to waxy solids at room temperature.

High pressure bulk polymerization is carried out in known high pressure reactors, e.g. Autoclaves or Tube reactors, carried out batchwise or continuously, have proven particularly useful Tubular reactors. Solvents such as aliphatic and / or aromatic hydrocarbons or Hydrocarbon mixtures, benzene or toluene can be contained in the reaction mixture. The solvent-free mode of operation is preferred. In a preferred embodiment of the Polymerization is the mixture of the monomers, the initiator and, if used, the Moderator, a tubular reactor via the reactor inlet and one or more side branches fed. The monomer streams can have different compositions here (EP-A-0 271 738).

The copolymers mentioned under B) are the mineral oils mentioned under A) or Mineral oil distillates added in the form of solutions or dispersions. These solutions or Dispersions preferably contain 1 to 90, in particular 10 to 80,% by weight of the copolymers. Suitable solvents or dispersing agents are aliphatic and / or aromatic Hydrocarbons or hydrocarbon mixtures, e.g. Gasoline fractions, kerosene, decane, Pentadecane, toluene, xylene, ethylbenzene or commercial solvent mixtures such as solvents Naphtha, "" Shellsol AB, "Solvesso 150," Solvesso 200, "Exxsol," ISOPAR and "Shellsol D types. The Fuel oils according to the invention preferably contain 0.001 to 2, in particular 0.005 to 0.5 % By weight of copolymer, based on the distillate.

The fuel oils of the invention may contain other oil-soluble co-additives that are already for only the flow properties of crude oils, lubricating oils or fuel oils improve. Examples such co-additives are copolymers containing vinyl acetate or terpolymers of ethylene, polar compounds which effect paraffin dispersion (paraffin dispersants), and Comb polymers.

Oil-soluble polar compounds with ionic or polar have been found as paraffin dispersants Groups, e.g. Amine salts and / or amides proven by the reaction aliphatic or aromatic Amines, preferably long-chain aliphatic amines, with aliphatic or aromatic mono-, di-, Tri- or tetracarboxylic acids or their anhydrides are obtained (cf. US-4 211 534). Other Paraffin dispersants are copolymers of maleic anhydride and α, β-unsaturated Compounds optionally with primary monoalkylamines and / or aliphatic alcohols can be implemented (cf. EP-A-0 154 177), the reaction products of alkenylspirobislactones with amines (cf. EP-A-0 413 279) and according to EP-A-0 606 055, reaction products of terpolymers based on α, β-unsaturated dicarboxylic anhydrides, α, β-unsaturated Compounds and polyoxyalkenyl ethers of lower unsaturated alcohols.

Comb polymers are polymers in which hydrocarbon radicals having at least 8, in particular at least 10, carbon atoms are bonded to a polymer backbone. They are preferably homopolymers whose alkyl side chains contain at least 8 and in particular at least 10 carbon atoms. In copolymers, at least 20%, preferably at least 30%, of the monomers have side chains (cf. Comb-like Polymers - Structure and Properties; NA Platé and VP Shibaev, J. Polym. Sci. Macromolecular Revs. 1974, 8, 117 ff). Examples of suitable comb polymers are, for example, fumarate / vinyl acetate copolymers (cf. EP-A-0 153 176), copolymers of a C ₆ -C ₂₄ -α-olefin and an NC ₆ - to C ₂₂ -alkylmaleimide (cf. EP- A-0 320 766), furthermore esterified olefin / maleic anhydride copolymers, polymers and copolymers of α-olefins and esterified copolymers of styrene and maleic anhydride.

The new fuel oils can contain other additives, for example Dewaxing agents, corrosion inhibitors, antioxidants, lubricity additives or Sludge inhibitors.

Examples

A1: Mit Cocosfettalkylamin imidiertes Ethylen-MSA-Copolymer mit 30 Gew.-% (8 mol-%) MSA.

A2: Ethylen-VeoVa-Copolymer mit 7 mol-% VeoVa 10 und einer V₁₄₀ von 200 mPas.

A3: Ethylen-VeoVa-Copolymer mit 14 mol-% VeoVa 10 und einer V₁₄₀ von 270 mPas.

A4: Ethylen-VeoVa-Copolymer mit 7 mol-% VeoVa 11 und einer V₁₄₀ von 84 mPas.

A5: Copolymerisat aus Ethylen und 8 mol-% Stearylacrylat mit einer V₁₄₀ = 65 mPas.

MSA =

Maleinsäureanhydrid

VeoVa 10/11 =

Neodecan-/Neoundecansäurevinylester

V₁₄₀ =

gemäß ISO 3219 mit Platte-Kegel-Meßsystem bei 140°C bestimmte Schmelzviskosität des Copolymers

The following additives A1 to A5 were produced:

A1: Ethylene-MSA copolymer imidized with coconut fatty alkylamine with 30% by weight (8 mol%) of MSA.

A2: Ethylene VeoVa copolymer with 7 mol% VeoVa 10 and a V ₁₄₀ of 200 mPas.

A3: Ethylene VeoVa copolymer with 14 mol% VeoVa 10 and a V ₁₄₀ of 270 mPas.

A4: Ethylene VeoVa copolymer with 7 mol% VeoVa 11 and a V ₁₄₀ of 84 mPas.

A5: Copolymer of ethylene and 8 mol% stearyl acrylate with a V ₁₄₀ = 65 mPas.

MSA =

maleic anhydride

VeoVa 10/11 =

Neodecanoic / Neoundecansäurevinylester

V ₁₄₀ =

according to ISO 3219 with plate-cone measuring system at 140 ° C determined melt viscosity of the copolymer

Effectiveness of the additives

Table 3 shows the effectiveness of the additives as flow improvers for mineral oil distillates using the CFPP test (Cold Filter Plugging Test according to EN 116) in various distillates from Scandinavian refineries. The additives are used as 50% solutions in solvent naphtha. As a comparison, the effectiveness of a commercially available ethylene-vinyl acetate copolymer (EVA copolymer) with 13.3 mol% of vinyl acetate and a melt viscosity V ₁₄₀ of 125 mPas (V1) and of a commercially available ethylene-vinyl acetate-neodecanoic acid vinyl ester terpolymer with 16 mol% % Vinyl acetate, 1.2 mol% neodecanoic acid vinyl ester and a melt viscosity V ₁₄₀ of 140 mPas (V2). Characterization of the test oils: Test oil 1 Test oil 4 Test oil 5 Test oil 6 Initial boiling point 195 ° C 190 ° C 192 ° C 183 ° C 20% 226 ° C 219 ° C 218 ° C 226 ° C 90% 280 ° C 291 ° C 288 ° C 330 ° C 95% 300 ° C 311 ° C 306 ° C 347 ° C Cloud point -30 ° C -24 ° C -27 ° C -9 ° C CFPP -31 ° C -29 ° C -34 ° C -12 ° C Pour point -30 ° C -27 ° C -27 ° C -21 ° C CFPP PP -1 ° C -2 ° C -7 ° C 9 ° C Density (15 ° C) 0,821 0,817 0.819 0.835

The CFPP is determined according to EN116, the PP according to ISO 3016 with an automatic device (Herzog MC 852).

List of trade names used

Solvent Naphtha ®Shellsol AB ®Solvesso 150 aromatic solvent mixtures with boiling range 180 to 210 ° C ®Solvesso 200 aromatic solvent mixture with boiling range 230 to 287 ° C ®Exxsol dearomatized solvents in various boiling ranges, for example "Exxsol D60: 187 to 215 ° C ®ISOPAR (Exxon) isoparaffinic solvent mixtures in various boiling ranges, for example "ISOPAR L: 190 to 210 ° C ®Shellsol D mainly aliphatic solvent mixtures in different boiling ranges

Claims (11)

1. The use of one or more copolymers containing from 85 to 97 mol% of bivalent structural units of the formula

   B1) -CH₂-CH₂- and from 3 to 15 mol% of one or more of the bivalent structural units B2)

   B2) -CH₂-CR¹R²-

   in which R¹ is hydrogen or methyl and R² is COOR³, OR³ or OCOR³, R³ being an alkyl radical having at least 8 and at most 24 carbon atoms, and which may contain up to 3 mol% of structural units derived from vinyl acetate or up to 5 mol% of structural units derived from further comonomers, for improving the cold flow properties of mineral oils having a sulphur content of less than 100 ppm, a cloud point of less than -8°C, a boiling range (90-20%) of less than 120°C and a difference between cold filter plugging point (CFPP) and pour point (PP) of less than 10°C.
2. The use as claimed in claim 1, wherein R¹ is hydrogen.
3. The use as claimed in claim 1 and/or 2, wherein R³ is a neoalkyl radical having 7 to 11 carbon atoms.
4. The use as claimed in claim 1 and/or 2, wherein R³ is C₈-C₁₈-alkyl or a neoalkyl radical having 8, 9 or 10 carbon atoms.
5. The use as claimed in one or more of claims 1 to 4, wherein the copolymers stated under B) have melt viscosities at 140°C of from 20 to 10,000 mPas, in particular from 30 to 5000 mPas, especially from 50 to 2000 mPas.
6. The use as claimed in one or more of claims 1 to 5, wherein the copolymers stated under B) contain vinyl esters, vinyl ethers, alkyl acrylates, alkyl methacrylates or higher olefins having at least 5 carbon atoms, preferably hexene, 4-methylpentene, octene or diisobutylene.
7. The use as claimed in one or more of claims 1 to 6, wherein the mineral oils have cloud points below -15°C.
8. The use as claimed in one or more of claims 1 to 7, wherein the mineral oils have boiling ranges (90-20%) of less than 100°C, in particular less than 80°C.
9. The use as claimed in one or more of claims 1 to 8, wherein the mineral oils have a 95% distillation point of less than 360°C.
10. The use as claimed in one or more of claims 1 to 9, wherein the copolymers stated under B) contain from 4 to 10 mol% of comonomers B2).
11. The use as claimed in one or more of claims 1 to 10, wherein the coadditives used are polar compounds which disperse paraffin (paraffin dispersants), comblike polymers, dewaxing assistants, corrosion inhibitors, antioxidants, lubricity additives or sludge inhibitors.