U.S. patent application number 11/331336 was filed with the patent office on 2006-06-01 for preparation of additive mixtures for mineral oils and mineral oil distillates.
This patent application is currently assigned to Clariant GmbH. Invention is credited to Curd-Werner Adams, Gerhard Bettermann, Matthias Krull, Werner Reimann.
Application Number | 20060112612 11/331336 |
Document ID | / |
Family ID | 31984316 |
Filed Date | 2006-06-01 |
United States Patent
Application |
20060112612 |
Kind Code |
A1 |
Krull; Matthias ; et
al. |
June 1, 2006 |
Preparation of additive mixtures for mineral oils and mineral oil
distillates
Abstract
The present invention provides a continuous process for
preparing additive mixtures for mineral oils and mineral oil
distillates, comprising A) a cold flow improver for middle
distillates, and at least one further component selected from B)
and C): B) a further cold flow improver, C) an organic solvent,
which comprises mixing cold flow improver and optionally solvent by
means of a static mixer, the temperature of the additive mixture at
the outlet of the static mixer being from 0.degree. to 100.degree.
C.
Inventors: |
Krull; Matthias; (Harxheim,
DE) ; Bettermann; Gerhard; (Voerde, DE) ;
Adams; Curd-Werner; (Oberhausen, DE) ; Reimann;
Werner; (Frankfurt am Main, DE) |
Correspondence
Address: |
CLARIANT CORPORATION;INTELLECTUAL PROPERTY DEPARTMENT
4000 MONROE ROAD
CHARLOTTE
NC
28205
US
|
Assignee: |
Clariant GmbH
|
Family ID: |
31984316 |
Appl. No.: |
11/331336 |
Filed: |
January 12, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10676962 |
Oct 1, 2003 |
7014667 |
|
|
11331336 |
Jan 12, 2006 |
|
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|
Current U.S.
Class: |
44/300 ; 44/385;
44/386; 44/412; 44/459; 524/563; 524/570; 524/81 |
Current CPC
Class: |
C08K 3/00 20130101; C10L
1/1966 20130101; C10L 1/1641 20130101; C10L 1/1973 20130101; C10L
1/1955 20130101; C10L 1/146 20130101; C10L 1/1981 20130101; C10L
1/1985 20130101; C10L 1/1963 20130101 |
Class at
Publication: |
044/300 ;
044/385; 044/386; 044/412; 044/459; 524/081; 524/563; 524/570 |
International
Class: |
C10L 1/10 20060101
C10L001/10 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 1, 2002 |
DE |
10245737.9 |
Claims
1-14. (canceled)
15. An additive mixture for improving cold flow properties of
mineral oils and mineral oil distillates, said additive mixture
being prepared in a continuous process by mixing: a cold flow
improver A) for middle distillates, and at least one further
component selected from the group consisting of a further cold flow
improver B), an organic solvent C), and mixtures thereof, in a
static mixer having an outlet temperature of from 0.degree. C. to
100.degree. C. to provide the additive mixture.
16. A fuel oil comprising a mineral oil or a mineral oil distillate
and the additive mixture of claim 1.
17. The additive mixture of claim 1, wherein the outlet temperature
is from 30 to 90.degree. C.
18. The additive mixture of claim 1, wherein the cold flow improver
comprises at least one copolymer of ethylene and further
ethylenically unsaturated comonomers.
19. The additive mixture of claim 1, wherein the cold flow improver
comprises at least one oil-soluble polar nitrogen compound.
20. The additive mixture of claim 1, wherein the cold flow improver
comprises at least one comb polymer.
21. The additive mixture of claim 1, wherein the cold flow improver
comprises at least one alkylphenol-aldehyde resin.
22. The additive mixture of claim 1, wherein the cold flow improver
comprises at least one polyoxyalkylene derivative.
23. The additive mixture of claim 1, wherein the cold flow improver
comprises at least one olefin copolymer.
24. The additive mixture of claim 1, wherein the static mixer
comprises a helical mixer having helical element groups having from
2 to 200 mixing elements.
25. The additive mixture of claim 1, wherein the static mixer has a
mixing zone having a relative mixer L/D of from 2 to 50, where L is
length and D is the diameter of the mixing zone.
26. The additive mixture of claim 1, wherein a pressure drop over
the mixing zone is less than 10 bar.
27. The process additive mixture of claim 1, wherein a mixing time
is less than 60 s.
28. The additive mixture of claim 1, wherein the cold flow improver
comprises a terpolymer which, apart from ethylene, contains from
0.1 to 12 mol %, of vinyl neononanoate or of vinyl neodecanoate,
and from 3.5 to 20 mol %, of vinyl acetate, and a total comonomer
content is between 8 and 21 mol %.
29. The additive mixture of claim 1, wherein the cold flow improver
comprises a terpolymer which, apart from ethylene and from 8 to 18
mol % of vinyl esters, also contains from 0.5 to 10 mol % of
olefins selected from the group consisting of propene, butene,
isobutylene, hexene, 4-methylpentene, octene, diisobutylene,
norbornene, and mixtures thereof.
30. The additive mixture of claim 1, wherein the outlet temperature
of the additive mixture at the outlet of the static mixer is from
50 to 85.degree. C.
31. The additive mixture of claim 1, wherein the cold flow improver
comprises a terpolymer which, apart from ethylene, contains from
0.2 to 5 mol %, of vinyl neononanoate or of vinyl neodecanoate, and
from 3.5 to 12 mol %, of vinyl acetate, and a total comonomer
content is between 8 and 21 mol %.
32. The additive mixture of claim 1, wherein the cold flow improver
comprises a terpolymer which, apart from ethylene, contains from
0.2 to 5 mol %, of vinyl neononanoate or of vinyl neodecanoate, and
from 8 to 15 mol %, of vinyl acetate, and the total comonomer
content is between 12 and 18 mol %.
33. The additive mixture of claim 1, wherein the cold flow improver
comprises a terpolymer which, apart from ethylene, contains from
0.1 to 12 mol %, of vinyl neononanoate or of vinyl neodecanoate,
and from 8 to 15 mol %, of vinyl acetate, and the total comonomer
content is between 12 and 18-mol %.
34. An additive mixture for improving cold flow properties of
mineral oils and mineral oil distillates, said additive mixture
being prepared by passing a cold flow improver to a static mixer
and therein mixing the cold flow improver with a further cold flow
improver selected from the group consisting of a further ethylene
copolymer, an oil-soluble polar nitrogen compound, a comb polymer,
an alkylphenol aldehyde resin, a polyoxyalkylene derivative, an
olefin copolymer, an organic solvent, and mixtures thereof, wherein
the cold flow improver and the further cold flow improver is a
copolymer of ethylene and at least one olefinically unsaturated
compound, the static mixer having from 2 to 200 mixing elements and
said static mixer having an outlet temperature ranging from
30.degree. C. to 90.degree. C. to provide said additive
mixture.
35. The additive mixture of claim 34, wherein the olefinically
unsaturated compound is selected from the group consisting of a
vinyl ester, an acrylic ester, a methacrylic ester, an alkyl vinyl
ether, an alkene, and mixtures thereof.
36. The additive mixture of claim 34, wherein the olefinically
unsaturated compound have alkyl groups which are substituted by one
or more hydroxyl groups.
37. The additive mixture of claim 34, wherein the mixing elements
are helical mixing elements.
Description
[0001] The present invention relates to a continuous process for
preparing sedimentation-stable additive mixtures for mineral oils
and mineral oil distillates using a static mixer.
[0002] Depending on the origin of the crude oils, crude oils and
middle distillates, such as gas oil, diesel oil and heating oil,
obtained from crude oils contain different amounts of n-paraffins
which, on reduction of the temperature, crystallize out as
platelet-shaped crystals and sometimes agglomerate with the
inclusion of oil. This agglomeration causes a deterioration in the
flow properties of the oils or distillates, which can result in
problems in the course of recovery, transport, storage and/or use
of the mineral oils and mineral oil distillates. When transporting
mineral oils through pipelines, the crystallization phenomenon,
especially in winter, can lead to deposits on the tube walls and in
a few cases, for example shutdown of a pipeline, even to their
complete blockage. When storing and further processing the mineral
oils, it may also be necessary in winter to store the mineral oils
in heated tanks. In the case of mineral oil distillates, possible
consequences of the crystallization include blockages of the filter
in diesel engines and firing plants, which prevents reliable
metering of the fuels and, under some circumstances, result in a
complete interruption of the fuel or heating medium feed. Alongside
the classical methods of eliminating the crystallized paraffins
(thermally, mechanically or using solvents) which are based solely
on the removal of the already formed precipitates, chemical
additives (known as flow improvers) have been developed in the last
few years. By physically interacting with the precipitated paraffin
crystals, these modify their shape, size and adhesion properties.
The additives function as additional crystal seeds and some of them
crystallize out with the paraffins, which results in a larger
number of smaller paraffin crystals having a changed crystal shape.
The modified paraffin crystals have a lower tendency to
agglomeration, so that the oils admixed with these additives can
still be pumped or processed at temperatures which are often more
than 20.degree. C. lower than in the case of nonadditized oils.
[0003] Examples of flow improvers of this type are copolymers of
ethylene and vinyl esters, acrylic esters or further olefinically
unsaturated compounds. Examples of other components used for this
purpose include paraffin dispersants, comb polymers, alkylphenol
resins, olefin copolymers and fatty alkyl esters of polyols.
[0004] A multiplicity of different crude oils is used for the
production of middle distillates. At the present time, the
processing in the individual refineries is effected in more or less
individual plant configurations. In addition, each refinery
produces distillate qualities of different specifications, for
example heating oil, summer diesel and winter diesel. For the
adjustment of the cold properties of these different oils,
additives optimized to the response behavior of the individual oils
have been developed in the last few years, in order to ensure very
low dosages and therefore reduced costs of on-spec configurations.
In addition, the processing means of the refinery with regard to
viscosity and pumpability of the additives have to be taken into
account by suitable choice of the active ingredient
concentration.
[0005] These special additives are frequently mixtures of different
active ingredients which are specially adapted to the oil to be
treated starting from a few basic active ingredients. Therefore,
current additives generally include more than just one component.
These mixtures can comprise different active ingredients of one
class or different groups.
[0006] Additives based on ethylene copolymers in particular are
semicrystalline polymers which are solid or highly viscous at room
temperature. Before processing to give additive formulations or
metering into middle distillates, they consequently have to be
heated and/or diluted to reduce the viscosity, in order to be
pumpable. This requires either constant warm storage or an
appropriate delay time for heating. In the latter case, rapid
heating in particular poses the risk of overheating in the region
of the heating elements in the storage tank.
[0007] According to the prior art, additive mixtures are prepared
batchwise, i.e. one or more active ingredient components and the
solvent are metered in succession into a vessel and then mixed by
stirring or circulation by pumping. This process is
disadvantageous, since charging, heating and mixing take a long
time. Especially in the case of mixing of active ingredients and
solvent of different viscosity, the achievement of a sufficient
homogeneity requires a relatively long period of stirring or
circulation over several hours to days. The desired or required
mixing temperature is generally attained only slowly depending on
the amounts of the components to be mixed and their temperatures
and also the heating output installed. However, it deviates
distinctly from the mean value at the metering point of the
components and also at the heating elements, for example. The
temperature profile during the mixing procedure can therefore only
be reproduced with difficulty. For a short-notice dispatch, a large
number of vessels of ready-formulated additive mixtures
additionally has to be maintained in the heated state in case
required.
[0008] A problem in the batchwise preparation of such formulations
if the fact that rapid heating in particular can result in
significant overheating at the heating elements, for example the
vessel jacket, which can lead on subsequent storage of the
additives prepared in this way to sedimentation of the suspended
active ingredients, especially the ethylene copolymers.
[0009] In addition, the flowability or pumpability of dispersions
of these semicrystalline polymers is in many cases dependent on the
mixing conditions. For instance, partially or incompletely molten
formulations of semicrystalline polymers with solvents and
optionally further active ingredients lead to dispersions having
high pour points, whereas completely molten polymers give
dispersions having distinctly lower pour points. The precise
setting of a constant pour point of the formulation prepared, which
is important for the product handling, is therefore possible in the
case of batchwise mixing only with additional high technical and/or
time demands, for example by heating or cooling the finished
mixture.
[0010] The object on which the present invention is based is
therefore to find a mixing process which avoids the disadvantages
mentioned. Firstly, the homogeneity and the sedimentation stability
of these mixtures should be improved. Secondly, it should enable
additive mixtures having different compositions to be prepared from
a few components at low cost and inconvenience and in a short time.
At the same time, the pour point of the mixture should be
controllable by the precise and rapid adjustment of the mixing
temperature.
[0011] It has been found that, surprisingly, the required
properties can be realized by a continuous mixing process which
works at a defined and constant temperature using a static
mixer.
[0012] The present invention provides a continuous process for
preparing additive mixtures for mineral oils and mineral oil
distillates, comprising [0013] A) a cold flow improver for middle
distillates, and at least one further component selected from B)
and C): [0014] B) a further cold flow improver, [0015] C) an
organic solvent, which comprises mixing cold flow improver and
optionally solvent by means of a static mixer, the temperature of
the additive mixture at the outlet of the static mixer being from
0.degree. C. to 100.degree. C.
[0016] For the purposes of the invention, cold flow improvers are
those materials which, in minor amounts of, for example, from 10 to
10 000 ppm, improve one or more cold flow properties of animal,
vegetable or mineral oils, for example cloud point, cold filter
plugging point, pour point and/or paraffin dispersancy. Such cold
flow improvers are, for example and not exclusively,
[0017] copolymers of ethylene and unsaturated esters, ethers and/or
olefins,
[0018] polar nitrogen compounds,
[0019] alkylphenol-aldehyde resins,
[0020] comb polymers,
[0021] olefin copolymers and
[0022] polyoxyalkylene derivatives.
[0023] The temperature of the mixture at the end of the static
mixer is preferably from 30 to 90.degree. C., in particular from 50
to 85.degree. C. The process according to the invention in
principle does not require constant temperature. Preference is
given to keeping the temperature constant at the outlet of the
static mixer during the mixing within .+-.10.degree. C., in
particular within .+-.5.degree. C.
[0024] The temperature of the cold flow improvers to be used is
preferably adjusted in such a way that their viscosity is below
5000 mPas, preferably between 1 and 1000 mPas and more preferably
between 10 and 500 mPas. Depending on the cold flow improver, these
are up to 150.degree. C., generally from 20 to 120.degree. C. The
solvent can have a higher or lower temperature. It is preferably
selected in such a way that the resulting mixing temperature
corresponds to the target temperature of the mixture.
Semicrystalline cold flow improvers can be used above or below
their cloud point. To set a low pour point, they are preferably
used above the cloud point. For instance, ethylene copolymers in
particular are preferably used at temperatures of from 20 to
120.degree. C., more preferably between 60 and 100.degree. C.
[0025] Static mixers are devices having stationary internals which
effect mixing of fluid product streams using flow energy. By
intensifying the turbulences in the tube through which flow occurs,
they reduce the zone required for attaining a sufficient standard
of mixing. In preferred embodiments, they consist of the same type
of mixing elements which are installed in succession in a channel
through which the product stream flows, individually or combined
into groups, and offset by 90.degree. relative to each other. The
mixing elements should be configured in such a way that they
spatially deflect and shear the product streams.
[0026] The choice of the suitable mixer depends not least on the
flow in the conveying tube: for instance, a laminar flow requires
more intensive separation, rearrangements and backmixing of the
stream than turbulent flow. The prior art includes a multiplicity
of designs of static mixers which are suitable for the process
according to the invention. With regard to the very different
designs of static mixers, reference is made to the review in M. H.
Pahl and E. Muschelknautz, Chem.-Ing.-Tech., volume 51 (1979),
pages 347 to 364, and this disclosure is incorporated in the
present application by way of reference.
[0027] Useful static mixers have proven to be, for example,
Multiflux, Sulzer, PMR, McHugh, Komax and Honeycomb, X, Ross-ISG
and helical mixers. Particular preference is given to helical
mixers having helical element groups of from 2 to 200, preferably
from 5 to 100 and especially from 10 to 50, mixing elements which
effect complete radial mixing, for example Kenics mixer.
[0028] Preference is given to using the static mixer in a pipeline
used for conveying the combined additive components between the
storage vessels of the flow improvers/solvent and the dispatch
vessel. Additive components which are added to the formulation in
minor proportions, for example up to 10% by volume, preferably up
to 5% by volume, can also be added directly to the static mixer via
an injection point. To attain a sufficient standard of mixing,
preference is given to a relative mixer length L/D of from 2 to 50,
in particular from 3 to 10, especially from 5 to 10, where L is the
length and D is the diameter of the mixing zone.
[0029] Preference is given to the static mixer being dimensioned in
such a way that the pressure drop over the mixing zone is less than
10 bar, in particular from 0.001 to 5 bar and especially from 0.05
to 1 bar.
[0030] In the simplest case, the pressure used to convey the
components is utilized for mixing. However, in the case of more
highly viscous formulations, it is also possible to use
pressure-increasing pumps.
[0031] The mixing temperature can be attained either before or
during the mixing procedure. Preference is given to metering the
active ingredient or ingredients and solvent or solvents preheated
into the mixing zone in such a way that the resulting mixture has
the desired temperature. In a preferred embodiment, the temperature
is adjusted in the mixing zone, for example, by means of a jacket
or of a tube bundle, which leads to particularly gentle temperature
adjusted.
[0032] To obtain a homogeneous mixture, the time required in the
process according to the invention is less than 60 seconds,
preferably less than 30 seconds, in particular less than 15 seconds
and especially less than 5 seconds. This corresponds substantially
to the time which the components require to flow through the static
mixer and is faster by a factor of from 100 to 10 000 than in the
case of batchwise mixing.
[0033] In a preferred embodiment, the cold flow improvers for
middle distillates comprise one or more copolymers of ethylene and
olefinically unsaturated compounds. Suitable ethylene copolymers
are in particular those which, apart from ethylene, contain from 6
to 21 mol %, in particular from 10 to 18 mol %, of comonomers.
These copolymers preferably have melt viscosities at 140.degree. C.
of from 20 to 10 000 mPas, in particular from 30 to 5000 mPas,
especially from 50 to 2000 mPas.
[0034] The olefinically unsaturated compounds are preferably vinyl
esters, acrylic esters, methacrylic esters, alkyl vinyl ethers
and/or alkenes, and the compounds mentioned may be substituted by
hydroxyl groups. One or more comonomers may be present in the
polymer.
[0035] The vinyl esters are preferably those of the formula 1
CH.sub.2.dbd.CH--OCOR.sup.1 (1) where R.sup.1 is C.sub.1 to
C.sub.30-alkyl, preferably C.sub.4 to C.sub.16-alkyl, especially
C.sub.6- to C.sub.12-alkyl. In a further embodiment, the alkyl
groups mentioned may be substituted by one or more hydroxyl
groups.
[0036] In a further preferred embodiment, R.sup.1 is a branched
alkyl radical or a neoalkyl radical having from 7 to 11 carbon
atoms, in particular having 8, 9 or 10 carbon atoms. Suitable vinyl
esters include vinyl acetate, vinyl propionate, vinyl butyrate,
vinyl hexanoate, vinyl heptanoate, vinyl octanoate, vinyl pivalate,
vinyl 2-ethylhexanoate, and also vinyl neononanoate, vinyl
neodecanoate, vinyl neoundecanoate, vinyl laurate and vinyl
stearate.
[0037] The acrylic esters are preferably those of the formula 2
CH.sub.2.dbd.CR.sup.2--COOR.sup.3 (2) where R.sup.2 is hydrogen or
methyl and R.sup.3 is C.sub.1-C.sub.30-alkyl, preferably
C.sub.4-C.sub.16-alkyl, especially C.sub.6-C.sub.12-alkyl. Suitable
acrylic esters include, for example, methyl (meth)acrylate, ethyl
(meth)acrylate, propyl (meth)acrylate, n- and isobutyl
(meth)acrylate, hexyl, octyl, 2-ethylhexyl, decyl, dodecyl,
tetradecyl, hexadecyl and octadecyl (meth)acrylate and also the
mixtures of these comonomers. In a further embodiment, the alkyl
groups mentioned may be substituted by one or more hydroxyl groups.
One example of such an acrylic ester is hydroxyethyl
methacrylate.
[0038] The alkyl vinyl ethers are preferably compounds of the
formula 3 CH.sub.2.dbd.CH--OR.sup.4 (3) where R.sup.4 is
C.sub.1-C.sub.30-alkyl, preferably C.sub.4-C.sub.16-alkyl,
especially C.sub.6-C.sub.12-alkyl. Examples include methyl vinyl
ether, ethyl vinyl ether, isobutyl vinyl ether. In a further
embodiment, the alkyl groups mentioned may be substituted by one or
more hydroxyl groups.
[0039] The alkenes are preferably monounsaturated hydrocarbons
having from 3 to 30 carbon atoms, in particular from 4 to 16 carbon
atoms and especially from 5 to 12 carbon atoms. Suitable alkenes
include propene, butene, isobutylene, pentene, hexene,
4-methylpentene, octene, diisobutylene and also norbornene and its
derivatives such as methylnorbornene and vinylnorbornene. In a
further embodiment, the alkyl groups mentioned may be substituted
by one or more hydroxyl groups.
[0040] Apart from ethylene, particularly preferred terpolymers
contain from 0.1 to 12 mol %, in particular from 0.2 to 5 mol %, of
vinyl neononanoate or vinyl neodecanoate, and from 3.5 to 20 mol %,
in particular from 8 to 15 mol %, of vinyl acetate, and the total
comonomer content is between 8 and 21 mol %, preferably between 12
and 18 mol %. Apart from ethylene and from 8 to 18 mol % of vinyl
esters, further particularly preferred copolymers also contain from
0.5 to 10 mol % of olefins such as propene, butene, isobutylene,
hexene, 4-methylpentene, octene, diisobutylene and/or
norbornene.
[0041] The process according to the invention can also be used to
prepare additive mixtures which comprise further constituents used
as cold flow improvers and/or mineral oil additives, for instance
paraffin dispersants, alkylphenol resins, comb polymers and polyol
esters.
[0042] Paraffin dispersants reduce the size of the paraffin
crystals and have the effect that the paraffin crystals do not
separate, but instead remain colloidally dispersed with a
distinctly reduced tendency to sediment. Useful paraffin
dispersants have proven to be oil-soluble polar compounds,
preferably nitrogen compounds, having ionic or polar groups, for
example amine salts and/or amides, which are obtained by reaction
of aliphatic or aromatic amines, preferably long-chain aliphatic
amines, with aliphatic or aromatic mono-, di-, tri- or
tetracarboxylic acids or their anhydrides (U.S. Pat. No.
4,211,534). Equally suitable paraffin dispersants are amides and
ammonium salts of aminoalkylene polycarboxylic acids such as
nitrilotriacetic acid or ethylenediaminetetraacetic acid with
secondary amines. Other paraffin dispersants are copolymers of
maleic anhydrides and .alpha.,.beta.-unsaturated compounds which
can optionally be reacted with primary monoalkylamines and/or
aliphatic alcohols (EP-A-0 154 177), the reaction products of
alkenyl-spiro-bislactones with amines (EP-A-0 413 279) and,
according to EP-A-0 606 055, reaction products of terpolymers based
on .alpha.,.beta.-unsaturated dicarboxylic anhydrides,
.alpha.,.beta.-unsaturated compounds and polyoxyalkenyl ethers of
lower unsaturated alcohols. Particularly preferred paraffin
dispersants contain reaction products of secondary fatty amines
having from 8 to 36 carbon atoms, in particular dicoconut fatty
amine, ditallow fatty amine and distearylamine with carboxylic
acids or their anhydrides.
[0043] Suitable paraffin dispersants also include
alkylphenol-formaldehyde resins. Alkylphenol-aldehyde resins are
described, for example, in Rompp Chemie Lexikon, 9th edition,
Thieme Verlag 1988-92, volume 4, p. 3351ff. The alkyl radicals of
the o- or p-alkylphenol in the alkylphenol-aldehyde resins which
can be used in the process according to the invention may be the
same or different and have 1-50, preferably 1-20, in particular
4-12, carbon atoms; they are preferably n-, iso- and tert-butyl, n-
and isopentyl, n- and isohexyl, n- and isooctyl, n- and isononyl,
n- and isodecyl, n- and isododecyl and octadecyl. The aliphatic
aldehyde in the alkylphenol-aldehyde resin preferably has 1-4
carbon atoms. Particularly preferred aldehydes are formaldehyde,
acetaldehyde and butyraldehyde, in particular formaldehyde. The
molecular weight of the alkylphenol-aldehyde resins is 400-10 000,
preferably 400-5000 g/mol. A prerequisite is that the resins are
oil-soluble.
[0044] In a preferred embodiment of the invention, these
alkylphenol-formaldehyde resins are those which contain oligo- or
polymers having a repeating structural unit of the formula ##STR1##
where R.sup.5 is C.sub.1-C.sub.50-alkyl or -alkenyl and n is a
number from 2 to 100.
[0045] 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. Preference is given to homopolymers
whose alkyl side chains contain at least 8 and in particular at
least 10 carbon atoms. In the case of copolymers, at least 20%,
preferably at least 30%, of the monomers have side chains (cf.
Comb-like Polymers--Structure and Properties; N. A. Plate and V. P.
Shibaev, J. Polym. Sci. Macromolecular Revs. 1974, 8, 117 ff).
Examples of suitable comb polymers are fumarate/vinyl acetate
copolymers (cf. EP-A-0 153 176), copolymers of a
C.sub.6-C.sub.24-olefin and an N--C.sub.6- to
C.sub.22-alkylmaleimide (cf. EP-A-0 320 766), and also esterified
olefin/maleic anhydride copolymers, polymers and copolymers of
.alpha.-olefins and esterified copolymers of styrene and maleic
anhydride.
[0046] For example, comb polymers can be described by the formula
##STR2##
[0047] In this formula,
[0048] A is R', COOR', OCOR', R''--COOR', OR';
[0049] D is H, CH.sub.3, A or R'';
[0050] E is H, A;
[0051] G is H, R'', R''--COOR', an aryl radical or a heterocyclic
radical;
[0052] M is H, COOR'', OCOR'', OR'', COOH;
[0053] N is H, R'', COOR'', OCOR, an aryl radical,
[0054] R' is a hydrocarbon chain having from 8 to 50 carbon
atoms;
[0055] R'' is a hydrocarbon chain having from 1 to 10 carbon
atoms;
[0056] m is an integer between 0.4 and 1.0; and
[0057] n is a number between 0 and 0.6.
[0058] The mixing ratio (in parts by weight) of the ethylene
copolymers with paraffin dispersants, alkylphenol resins or comb
polymers is in each case 1:10 to 20:1, preferably from 1:1 to
10:1.
[0059] Olefin polymers suitable for use as cold flow improvers in
the process according to the invention can be derived directly from
monoethylenically unsaturated monomers or be derived indirectly by
hydrogenation of polymers which are prepared from polyunsaturated
monomers such as isoprene or butadiene. In addition to ethylene,
preferred copolymers contain structural units which are derived
from .alpha.-olefins having from 3 to 24 carbon atoms and molecular
weights of up to 120 000. Preferred .alpha.-olefins are propylene,
butene, isobutene, n-hexene, isohexene, n-octene, isooctene,
n-decene, isodecene. The comonomer content of olefins is preferably
between 15 and 50 mol %, more preferably between 20 and 35 mol %
and especially between 30 and 45 mol %. These copolymers can also
contain small amounts, for example up to 10 mol %, of further
comonomers, for example nonterminal olefins or nonconjugated
olefins. Preference is given to ethylene-propylene copolymers.
[0060] The olefin copolymers can be prepared by existing methods,
for example by means of Ziegler or metallocene catalysts.
[0061] Further suitable flow improvers are polyoxyalkylene
compounds, for example esters, ethers and ether/esters which bear
at least one alkyl radical having from 12 to 30 carbon atoms. When
the alkyl groups are derived from an acid, the radical is derived
from a polyhydric alcohol; when the alkyl radicals come from a
fatty alcohol, the radical of the compound is derived from a
polyacid.
[0062] Suitable polyols are polyethylene glycols, polypropylene
glycols, polybutylene glycols and their mixed polymers having a
molecular weight of from approx. 100 to approx. 5000, preferably
from 200 to 2000. Also suitable are alkoxylates of polyols, for
example glycerol, trimethylolpropane, pentaerythritol, neopentyl
glycol, and also the oligomers obtainable therefrom by condensation
and having from 2 to 10 monomer units, for example polyglycerol.
Preferred alkoxylates are those having from 1 to 100 mol, in
particular from 5 to 50 mol, of ethylene oxide, propylene oxide
and/or butylene oxide per mole of polyol. Particular preference is
given to esters.
[0063] Fatty acids having from 12 to 26 carbon atoms are preferably
used for reaction with the glycols to form the ester additives,
although preference is given to using C.sub.18- to C.sub.24-fatty
acids, especially stearic acid and behenic acid. The esters can
also be prepared by esterification of polyoxyalkylated alcohols.
Preference is given to fully esterified polyoxyalkylated poylols
having molecular weights of from 150 to 2000, preferably from 200
to 600. PEG-600 dibehenate and glycerol-20-ethylene glycol
tribehenate are particularly suitable.
[0064] The additive concentrates can be used in the mixing process
prediluted with solvent or preferably solvent-free, and more highly
viscous, waxy substances are preferably used in heated form. The
prerequisite is merely that the raw materials are flowable and
pumpable.
[0065] The process according to the invention relates, for example,
to the mixing of two cold flow improvers, of one cold flow improver
with a solvent, or of two cold flow improvers with a solvent. The
process according to the invention likewise relates, for example,
to the mixing of one, two or more cold flow improvers with two or
more solvents. It is also possible to mix together one or more, for
example two, three, four, or else more cold flow improvers and one
or more solvents. The proportion of the individual cold flow
improvers in the mixture (in parts by weight; without solvent) is
between 1 and 90% by weight, preferably between 2.5 and 80% by
weight and especially between 5 and 70% by weight. The solvent
proportion is between 10 and 95% by weight, preferably between 20
and 80% by weight, especially between 25 and 75% by weight. In the
case of dilutions, for example of ethylene copolymers, it is also
possible for one active ingredient alone to be present.
[0066] Suitable solvents or dispersants are aliphatic and/or
aromatic hydrocarbons or hydrocarbon mixtures, for example
petroleum fractions, kerosene, decane, pentadecane, toluene,
xylene, ethylbenzene or commercial solvent mixtures such as Solvent
Naphtha, .RTM.Shellsoll AB, .RTM.Solvesso 150, .RTM.Solvesso 200,
.RTM.Exxsol, .RTM.ISOPAR and .RTM.Shellsol D types. The solvent
mixtures specified contain different amounts of aliphatic and/or
aromatic hydrocarbons. The aliphatics may be straight-chain
(n-paraffins) or branched (isoparaffins). Aromatic hydrocarbons may
be mono-, di- or polycyclic and optionally bear one or more
substituents. Polar solubilizers, for example butanol,
2-ethylhexanol, decanol, isodecanol or isotridecanol or higher
ethers and/or esters can also optionally be added. In addition to
solvents based on mineral oils, solvents based on renewable raw
materials are also suitable, for example biodiesel based on
vegetable oils and the methyl esters derived therefrom, in
particular rapeseed oil methylester, and also synthetic
hydrocarbons which are obtainable, for example, from the
Fischer-Tropsch process.
[0067] The additive mixtures prepared by the process according to
the invention are suitable for improving the cold flow properties
of animal, vegetable or mineral oils. They are particularly
suitable for use in middle distillates. Middle distillates are in
particular those mineral oils which are obtainable by distillation
of crude oil and boil in the range from 120 to 450.degree. C., for
example kerosene, jet fuel, diesel and heating oil. Preference is
given to using those middle distillates which contain less than 350
ppm of sulfur, more preferably less than 200 ppm of sulfur, in
particular less than 50 ppm of sulfur and in special cases less
than 10 ppm of sulfur. These are generally those middle distillates
which have been subjected to refining under hydrogenating
conditions, and therefore contain only small proportions of
polyaromatic and polar compounds. They are preferably those middle
distillates which have 95% distillation points below 370.degree.
C., in particular 350.degree. C. and in special cases below
330.degree. C.
[0068] The additive mixtures according to the invention can also be
used in biodiesel. "Biodiesel" or "biofuel" are fatty acid alkyl
esters of fatty acids having from 14 to 24 carbon atoms and
alcohols having from 1 to 4 carbon atoms. Usually, a relatively
large portion of the fatty acids contains one, two or three double
bonds. These are more preferably, for example, rapeseed oil
methylester and its mixtures with further vegetable oil esters. The
additives according to the invention can be used with the same
success in mixtures of fatty acid methyl esters and mineral oil
diesel. Such mixtures preferably contain up to 25% by weight, in
particular up to 10% by weight, especially up to 5% by weight, of
fuel oil of animal or vegetable origin.
[0069] Mineral oils or mineral oil distillates improved in their
cold properties by the additive mixtures contain from 0.001 to 2%
by volume, preferably from 0.005 to 0.5% by volume, of the
mixtures, based on the distillates.
[0070] The process according to the invention increases the
flexibility in the production of a multiplicity of highly differing
additive mixtures from the small number of starting materials on
which they are based. These additive mixtures can be produced at
low capital cost with simultaneously low operating and maintenance
costs. In addition, the setting of a defined and reproducible
mixing temperature achieves a distinctly improved storage stability
even at low temperatures. The extremely rapid mixing procedure
makes possible reproducible setting of the colloidal and
rheological properties, for example the pour point.
[0071] The additive mixtures can be used alone or else together
with other additives, for example with pour point depressants,
dehazers, antistats, antioxidants, conductivity improvers,
lubricity additives, cetane number improvers and additives for
reducing the cloud point. In addition, they are used successfully
together with additive packages which contain, inter alia, known
ashless dispersants, detergents, antifoams, demulsifiers, and
corrosion inhibitors. These further additives can of course also be
added to the additive mixtures according to the invention in the
course of the process according to the invention.
EXAMPLES
[0072] TABLE-US-00001 TABLE 1 Raw materials used E1 Copolymer of
ethylene and 28% by weight of vinyl acetate having a melt viscosity
at 140.degree. C. of 250 mPa s E2 Terpolymer of ethylene, 30% by
weight of vinyl acetate and 8% by weight of vinyl neodecanoate
having a melt viscosity at 140.degree. C. of 95 mPa s E3 Terpolymer
of ethylene, 26% by weight of vinyl acetate and 7% by weight of
4-methylpentene having a melt viscosity at 140.degree. C. of 200
mPa s E4 Tetradecanol-esterified copolymer of maleic anhydride and
tetradecene, 65% in Solvent Naphtha E5 Reaction product of a
terpolymers of C.sub.14/C.sub.16-.alpha.-olefin, maleic anhydride
and allyl polyglycol with 2 equivalents of ditallow fatty amine,
62% in Solvent Naphtha E6 Behenic acid-esterified glycerol-20
ethoxylate, 70% in Solvent Naphtha E7 Copolymer of ethylene and
34.5% by weight of vinyl acetate having a melt viscosity at
140.degree. C. of 105 mPa s E8 Copolymer of ethylene and 21% by
weight of vinyl acetate having a melt viscosity at 140.degree. C.
of 530 mPa s
[0073] Experiment 1
[0074] 10 000 kg of the polymer E1 (heated to 65.degree. C.) and 10
500 kg of kerosene (T=55.degree. C.) are metered in parallel into a
conveying tube over the course of two hours and conveyed via a
static mixer equipped with helical elements and having a diameter
of 100 mm and a length of 2000 mm. The pressure drop over the
static mixer is 0.2 bar, the mixing time 2.5 seconds. The resulting
mixing temperature is 60.degree. C. This results in a homogeneous
49% polymer suspension which is fully homogeneous even after
storage at 40.degree. C. for 7 days.
[0075] Experiment 2
[0076] The procedure of experiment 1 was repeated, except that the
polymer E1 was fed to the mixing zone at 75.degree. C. and the
solvent at 85.degree. C., which results in a mixing temperature of
81.degree. C. The initially almost clear solution becomes cloudy on
cooling and is still fully homogeneous after storage at 40.degree.
C. for 7 days.
[0077] Experiment 3 (Comparative)
[0078] The procedure of experiment 1 was repeated, except that the
polymer E1 was fed to the mixing zone at 90.degree. C. and the
solvent at 115.degree. C., which results in a mixing temperature of
98.degree. C. The initially almost clear solution becomes cloudy on
cooling and, after storage at 40.degree. C. for two days, exhibits
a clear supernatant of approx. 6% by volume; after 7 days of
storage, the formulation exhibits 39% by volume of polymer sediment
and a clear supernatant.
[0079] Experiment 4 (Comparative)
[0080] 10 000 kg of the polymer E1 and 10 500 kg of kerosene are
charged to a vessel and heated to 60.degree. C. by means of jacket
heating (vapor temperature 120.degree. C.). After 3 hours of
circulation, the mixture still exhibits distinct inhomogeneities;
only after 8 hours is it homogeneous. After storage at 40.degree.
C. for 2 days, this suspension consists of 60% by volume of a
milky, white bottom phase and an opaque supernatant. After storage
at this temperature for 7 days, 25% by volume of polymer have
sedimented, and the supernatant is clear.
[0081] Experiment 5
[0082] 5000 kg of the 49% polymer suspension from experiment 1 at a
temperature of 60.degree. C. and 7250 kg of kerosene at a
temperature of 25.degree. C. are simultaneously conveyed through
the static mixer from experiment 1 within one hour. The mixing
temperature of the formulation is 38.degree. C. The resulting 20%
polymer suspension is homogeneous and shows no sedimentation even
after storage at 25.degree. C. for two weeks.
[0083] Experiment 6 (Comparative)
[0084] 5000 kg of the 49% polymer suspension from experiment 1 are
charged to a vessel, heated to 60.degree. C. by means of jacket
heating (vapor temperature 120.degree. C.) with circulation in the
course of 6 hours and subsequently diluted with 7250 kg of
kerosene. After 4 hours of circulation, a homogeneous suspension is
obtained. After storage at 25.degree. C. for 2 days, this
suspension exhibits approx. 8% by volume of a bottom phase which is
enriched with polymer and, after a week, begins to become clear in
the upper region and, after two weeks, consists of 12% by volume of
polymer sediment and a clear supernatant.
[0085] Experiment 7
[0086] 7680 kg of polymer E2 and 1920 kg of polymer E3 at
temperatures of 70.degree. C. and 72.degree. C. are conveyed
continuously through the static mixer described in experiment 1
together with 6400 kg of kerosene (T=55.degree. C.) over the course
of 80 minutes. The mixing temperature is 64.degree. C. The
resulting 60% suspension is fully homogeneous even after storage at
35.degree. C. for two weeks.
[0087] Experiment 8 (Comparative)
[0088] The components of experiment 7 are mixed at 60.degree. C. by
the process of comparative experiment 4. After storage at
35.degree. C. for two weeks, this suspension exhibits 20% of
polymer sediment, and above that approx. 40% by volume each of an
opaque and of a clear phase.
[0089] Experiment 9
[0090] 5000 kg of polymer E3 and 1540 kg of polymer E4 at
temperatures of 75.degree. C. and 55.degree. C. are continuously
conveyed through the static mixer described in experiment 1
together with 5460 kg of kerosene (T=65.degree. C.) over the course
of 90 minutes. The mixing temperature is 67.degree. C. The
resulting 50% suspension is homogeneous even after storage at
40.degree. C. for two weeks.
[0091] Experiment 10
[0092] 5500 kg of polymer E2 (T=94.degree. C.), 3550 kg of polymer
E5 (T=45.degree. C.) and 1570 kg of polymer E6 (T=72.degree. C.)
are conveyed continuously through the static mixer described in
experiment 1 together with 5380 kg of kerosene (T=53.degree. C.)
over the course of 90 minutes. The mixing temperature is 66.degree.
C. The resulting 55% suspension is homogeneous even after storage
at 40.degree. C. for three weeks.
[0093] Experiments 11 to 15: Setting of the Pour Point
[0094] In the mixing apparatus of experiment 1, 9000 kg of a
mixture of 7200 kg of polymer E7 and 1800 kg of polymer E8 were
mixed with 9000 kg of kerosene at different temperatures. Table 2
reports the temperatures of the polymers, solvent and resulting
formulation, the visual appearance of the polymer and also the pour
points of the formulations measured. The pour point is determined
to ISO 3015. TABLE-US-00002 TABLE 2 Experiments for influencing the
pour point Experiment T.sub.Polymer T.sub.Solvent T.sub.Mixture
Pour point 11 95.degree. C. (clear) 75.degree. C. 84.degree. C.
-3.degree. C. 12 92.degree. C. (clear) 32.degree. C. 61.degree. C.
-3.degree. C. 13 81.degree. C. (opalescent) 77.degree. C.
81.degree. C. 0.degree. C. 14 69.degree. C. (opalescent) 94.degree.
C. 82.degree. C. 3.degree. C. 15 53.degree. C. (cloudy) 92.degree.
C. 72.degree. C. 18.degree. C.
* * * * *