JP2760886B2 - Mineral oil and mineral oil products with improved flow properties - Google Patents

Abstract

The invention relates to mineral oils and mineral oil products of improved flow behaviour, from the group of crude oils, vacuum gas oils or residual oils, having a content of long-chain polyalkyl (meth)acrylates, the long-chain polyalkyl (meth)acrylates representing a mixture of A) a polyalkyl (meth)acrylate P1 having crystallisation starting temperatures above 15 degrees C (measured as the cloud point of a 0.1 % solution in isooctane) and B) a polyalkyl (meth)acrylate P2 having crystallisation starting temperatures at or below 15 degrees C, with the proviso that there is a temperature difference of at least 5 degrees C between the start of the crystallisation of the polyalkyl (meth)acrylates P1 and the start of the crystallisation of the polyalkyl (meth)acrylates P2.

Description

Description: FIELD OF THE INVENTION The present invention relates to mineral oils and mineral oil products with improved rheological properties containing a mixture of different defined polyalkyl (meth) acrylates as flow improvers. .

BACKGROUND OF THE INVENTION The low temperature properties of mineral oils and mineral oil products are critically affected by the paraffins contained therein. Paraffin crystallizes when cooled. Thereby, the fluidity of the oils is reduced or hindered. Generally, upon heating, the paraffin dissolves back into the oil matrix. Polymer flow improvers such as "Pour Point-Erniedrige
r), which effectively lowers the "pour point" (temperature at which the oil is still free flowing, see DIN 51,597), even at concentrations of 0.05-1% by weight. Its mechanism of action was almost described by the following model: paraffin analogs were incorporated into the growing paraffin crystal surface, preventing further crystal growth and extensive crystal structure growth (Ullman
ns Encyclopaedie der tech.Chemie 4th ed., Volume 20, 54
8, see Verlag Chemie, 1981).

Polymers based on (meth) acrylates of long-chain alcohols (C> 12) are suitable as flow-improving agents with considerable effectiveness on crude oils (cf. DE-A 17 70 695). Polybehenyl acrylate is suitable, for example, as a prototype of a flow improver for crude oil. Polybehenyl acrylate itself has a temperature of +20
At a temperature of 0.1% in isooctane by the method of determination of the "cloud point" according to DIN 51 547 and ASTM D 97-66.
), The prediction that it can interact with long chain paraffins in crude oil is very satisfactory. The use of polybehenyl acrylate and comparable long-chain polyacrylates is clearly an obstacle to the high cost of the starting materials. German Patent Application No. P38 18 438 (unpublished) describes a paraffin-containing mineral oil with improved flow properties consisting of the group consisting of crude oil, Vakuum Gasoel and residua. In the mineral oil, the crystallization of paraffin is started at a temperature of <30, and the crystallization temperature is at least 15 ° C or lower, and at least one kind of polymer P1 to Pd1 selected from the group of polyalkyl (meth) acrylate or polydialkyl fumarate Means containing 10,000ppm.

[Problems to be Solved by the Invention] Long-chain alkyl esters of (meth) acrylic acid, especially C
₁₈ -C ₂₄ - alkyl esters, also know idea on which they are based the prior art that can improve the cold flow properties of crude oil, can contribute to the optimization of the fluidity improving effect of polyalkyl (meth) acrylate Technical rules were not recognized.

Nevertheless, the relatively high cost of such flow improvers according to the prior art has been a challenge for cheaper raw materials and as much or as good a solution as possible.

As an important index for measuring the fluidity improving effect, for example, the relationship between the onset of crystallization of paraffin in oil and temperature can be measured (A. Ecker “Erdoel und
Kohle "38 (6) 281 (1985); A. Ecker" Erdoel, Erdg
as "101, 154 (1982) ; BLBlain, NGLI-Spokesman, June
1976).

The paraffin present in the oil dissipates heat when cooled and crystallizes. The heat dissipated can be detected as a peak of exotherm using differential thermal analysis (DTA) or, preferably, differential scanning calorimetry (DSC), which allows a good measure of the onset of paraffin crystallization, while Inspection-based measurements of the "Wax Appearance Point" or "cloud point" are generally useless for dark colored products and residual oils.

[Means for Solving the Problems] By the way, it has been found that a specific mixture of polyalkyl (meth) acrylates satisfies this technical need. This was all the more surprising since such polyalkyl (meth) acrylate components were previously thought to have been ineffective or had been rated as having a significantly lower effect. There is also a synergistic effect. The present invention relates to a group of mineral oils and mineral oil products consisting of crude oils, vacuum gas oils and resids having improved flow properties containing long chain polyalkyl (meth) acrylates.
Here, the long-chain polyalkyl (meth) acrylates are: A) polyalkyl (meth) acrylates P1 and B, which start crystallization above 15 ° C. (measured as the cloud point of a 0.1% solution of isooctane according to DIN 51,597) A) the temperature difference between the start of the crystallization of the polyalkyl (meth) acrylate in A) and the start of the crystallization or precipitation of the polyalkyl (meth) acrylate in section B) is at least 5 ° C, preferably 10 ° C; Consisting of a mixture of polyalkyl (meth) acrylates P2 which initiate crystallization or precipitation at a temperature of 150 ° C. or lower.

The ratio between the two polymer components P1 and P2 is preferably from 1:50 to 50: 1, and particularly preferably from 1:10 to 10: 1.

Polyalkyl (meth) acrylates P1 and P2 The difference between polyacrylates and polymethacrylates of long-chain alcohols and esters of lower alcohols is due to the tendency of crystallization (side-chain crystallization). Is known, in this case, the position of the melting point, the number of carbon atoms of the side chain in the homopolymer or copolymer, that is, the length,
It is critically influenced by the number and distribution.

The polyalkyl (meth) acrylate P1 of type A having an association temperature of 15 ° C. or higher is formed from a monomer comprising an alkyl group having C18 or higher, or a monomer containing most of the same. Preferably alkanol C ₁₈ -C _26, especially polyalkyl (meth) acrylate of an alkanol of C ₁₈ -C _24, in particular poly behenyl acrylate (Polymer P1-a) is suitable.

The type B polyalkyl (meth) acrylate P2 having an association temperature (onset of crystallization) of 15 ° C. or lower required by the present invention is a polymer of acrylic acid or methacrylic acid, particularly a long-chain alkanol (C ₁ or more, preferably C ₈ ~C
_40), also C ₁₆ -C ₂₄ - those having an alkyl group in which the choice association temperature to satisfy the above criteria (<15 ° C.). The following selection criteria are used: polymerization or copolymerization of acrylic acid esters having an alkyl group of -18 C atoms or less, preferably 12-18 C atoms.

- preferably an alkyl group having C ₁₂ -C _40, polymerization or copolymerization of an ester of methacrylic acid instead of acrylic acid.

-Copolymerization with monomers which do not have the ability to crystallize in the side chains, in particular monomers having an alkyl group of C ₁₀ or less or a branched C ₁ -C ₄₀ alkyl group.

For example, the following types of polymers satisfy the above conditions: polytallow acrylate (C ₁₆ -C ₁₈ -alkyl acrylate) = P 2 -a, polybehenyl methacrylate (C ₁₈ -C ₂₄₎
- alkyl methacrylate) = P2-b, behenyl acrylate (C ₁₈ -C ₂₄ - alkyl acrylate) and copolymers from isodecyl acrylate = P2-c.

The molecular weight of the polymers P1 and P2 is generally between 5000 and 100,000
0, preferably between 10,000 and 500,000. Generally, this molecular weight range is maintained using known molecular weight regulators, for example the type of sulfur regulators (H. Rauch-Puntigam, Th.V.
oelker, Acryl-und Methacrylverbindungen, Springer-
Verlag, Berlin 1967). In particular, mercaptans such as dodecyl mercaptan are used in an amount of 0.01 to 2% by weight, based on the monomers. The molecular weight was measured by gel permeation chromatography using polymethyl methacrylate as a standard substance (Kirk-Othmer, Encyclopedia of Chemical Tech).
nolog, 3rd edition, vol. 18, p. 209, 749, J. Wiley, 1982).

The starting monomers are known per se or can be prepared in a manner known per se, for example by transesterification of lower (meth) acrylates, for example methyl or ethyl esters, with higher alcohols. Production of the polymer is then possible by conventional radical polymerization methods (H.
Rauch-Puntingam.Th.Voelker Acryl-und Methacrylve
rbindungen, Springer-Verlag, Berlin, 1967). The polymerization medium is an inert medium and mineral oil itself, for example, 100N
Oil (100N-oel) is recommended.

As the polymerization vessel, a conventional one is used, which is provided with a stirrer, a heating device, a thermometer, a reflux condenser, and a raw material feed pipe according to the purpose. React in gas. Further, a conventional radical initiator is used, but preferably a perester, a peroxide or an azo compound such as t-butyl perbenzoate or t-butyl perpivalate is added in a usual concentration, for example, 0.1 to 5% by weight based on the total weight of the monomers. %, Preferably at a concentration of 0.3-1% by weight. In general, the process is carried out at elevated temperatures, preferably above 60 ° C., particularly preferably 70 ° C.
Starting at −90 ° C., where the polymerization initiator is added and the temperature is 80
A peak is reached which may be above ℃, preferably 140 ± 10 ℃. In some cases, the polymerization initiator can be added again, and if necessary, post-polymerization can be performed by heating. Generally, the polymerization is completed within 5 hours.

Mineral oil Mineral oil or mineral oil products whose properties, in particular the temperature-dependent rheological properties, are improved according to the invention are mainly the following group of mineral oil products: crude oil, boiling point range from 320 to 500 ° C. (true). Vacuum oil at-boiling point)-Residues (distillate resids distilled above 350 ° C) (Winnacker-Kuechler, Chemisch Technologie Volume 5,
4th edition, Carl Hanser Verlag, Muenchen, 1981).

The onset of temperature-related paraffin crystallization (CP) is
It is an important characteristic value for the mineral oil producing area or the mineral oil used, and its measurement is performed by a specialist on a daily basis. A preferred measurement method is DSC as described above.

Generally, the content of polymer P1 in mineral oil is 50-2000 ppm
In order to improve its flowability, it is 10,000, especially 50 to 2000 ppm, depending on the place of production.

 After polymerization, the polymer P is preferably a suitable solvent, for example,
Hydrocarbons, such as xylene, toluene, kerosene, sherzo
Le (SHELLSOL) Can be diluted. in this way
The resulting solution can be used to produce a mineral oil mixture. Special
Otherwise, transfer this solution to the top of the borehole
Can be sent directly to the pipeline.

The polymer P is preferably in the form of a solution as described above, preferably at a high temperature, e.g.
Mix at ~ 80 ° C. The effect of the flow improving additive is maintained during normal transport. In addition to the polyalkyl (meth) acrylates P1 and P2 of the present invention, no other flow improvers need be added, but different ingredients such as, for example, emulsion inhibitors can be added.

[Function and Effect] The excellent flow improving effect of the mixture of A) and B) is attributable to the polymer.
It was expected that P2 itself had an association temperature of less than 15 ° C., had no effect on its own, and had very little if any. In the case of this combination, good to equivalent effects were obtained from the polymer P1 alone, in view of the amount of the polymer used.

A clear synergistic effect was observed in each case. Even in the case of less excellent and comparable effects, the second component is readily available and inexpensive, which is a significant advantage.

A model was considered for the unexpected synergistic effect of the polymer components P1 and P2, but this discussion does not affect the technical idea of the present invention, and in the first phase, the component having a high self-association temperature Affects the crystallization of crude long chain paraffins. In the second “low temperature phase”, the second component having a low self-association temperature is effective. This leads to one selection criterion for an advantageous combination, but it should be understood that this is only a rough guide, as there are exceptions and overlaps.

If polybehenyl acrylate is used as component A), it is possible, for example, to start from the following batches: in crude oils in which polybehenyl acrylate reduces the cloud point up to 0 ° C., a mixture with a self-association temperature of 0 to 15 ° C. Component B) is suitable. In the case of crude oils which can lower the cloud point below -5 ° C. with polybehenyl acrylate, mixtures B) having a self-association temperature below -5 ° C. are optimal.

[Example] The present invention will be described in detail with reference to the following examples.

Example 1 Preparation of polybehenyl acrylate P1-a 100 l behenyl acrylate (C18-24-
(Acrylate) 51 kg, 100 N oil 9 kg and dodecyl mercaptan 0.051 kg were charged, degassed with CO ₂ -ice, and heated to 70 ° C. Then 0.191 kg of t-butyl perpivalate and 0.115 kg of t-butyl perbenzoate were added to start the polymerization. One hour after the temperature reached 134 ° C., 0.077 kg of dodecyl mercaptan and t-
0.051 kg of butyl perbenzoate was added, followed by polymerization at 130 ° C. for 3 hours.

Molecular weight (GPC, PMMA standard) = 560,000 g / mol η _sp / c (CHCl ₃ , 20 ° C.) = 48 ml / g Cloud point (0.1% isooctane) = 19.5 ° C. Example 2 Preparation of polybehenyl methacrylate P2-b Behenyl methacrylate (C18-24
Methacrylate), 30 kg of 100N oil and 0.60 kg of dodecyl mercaptan. After degassing the mixture with CO ₂ -ice, it was heated to 70 ° C. and 0.60 kg of t-butyl perpivalate was added. 2 hours after reaching 96.5 ° C
Heat to 130 ° C. and add 0.03 kg of dodecyl mercaptan and 0.06 kg of t-butyl perbenzoate. After 5 hours, the polymerization was stopped.

Molecular weight (GPC, PMMA standard) = 24,300 g / mol η _sp / c (CHCl ₃ , 20 ° C.) = 11 ml / g Cloud point (in 0.1% isooctane) = − 2 ° C. Example 3 Preparation of polytallow acrylate P2-a 200 l Was charged with 102 kg of tallow acrylate (C16-18-acrylate), 18 kg of 100N oil and 2.55 kg of dodecylmercaptan. The mixture was degassed by the addition of CO ₂ -ice and then warmed to 70 ° C. Then 0.612 kg of t-butyl perpivalate was added. The temperature rose to 142 ° C. 1-2 hours after reaching the peak maximum temperature,
At 130 ° C., 0.204 kg of dodecyl mercaptan and 0.102 kg of t-butyl perbenzoate, respectively, were added. After 5 hours, the polymerization was stopped.

Molecular weight (GPC, PMMA standard) = 20,100 g / mol η _sp / c (CHCl ₃ , 20 ° C.) = 9.3 ml / g Cloud point (in 0.1% isooctane) = 9.5 ° C. Example 4 Production of polytallow acrylate P2-a 150 l Was charged with 85 kg of tallow acrylate (acrylate of C16-18), 15 kg of 100N oil and 0.425 kg of dodecyl mercaptan. The mixture was degassed by adding CO ₂ -ice and then heated to 70 ° C. Then, 0.425 kg of t-butyl perpivalate was added. The temperature rose to 148 ° C. One and two hours after reaching peak temperature, 13
At 0 ° C., 0.17 kg of dodecyl mercaptan and t
0.085 kg of butyl perbenzoate were added. After 5 hours, the polymerization was stopped.

Molecular weight (GPC, PMMA standard) = 118,000 g / mol η _sp / c (CHCl ₃ , 20 ° C) = 21 ml / g Cloud point (in 0.1% isooctane) = + 10 ° C Example 5 Copolymer P2- of behenyl methacrylate and methyl methacrylate Production of c Behenyl methacrylate (C18-2
4 methacrylate) 67.1kg, methyl methacrylate 7.9
kg, 100N oil 75kg and dodecyl mercaptan 1.875k
g. The mixture was degassed by adding CO ₂ -ice and then heated to 70 ° C. Then 0.3 kg of t-butyl perpivalate was added, which raised the temperature to 94 ° C.
Dodecyl mercaptan at 70 ° C 5 hours after the start of the reaction
An additional 0.075 kg and 0.15 kg t-butyl perpivalate were added. After another 6 hours, the polymerization was stopped at 70 ° C.

Molecular weight (GPC, PMMA standard) = 26,000 g / mol η_sp/ c (CHCl_Three, 20 ° C) = 11 ml / g Cloud point (in 0.1% isooctane) = -7 ° C Example 6 Preparation of poly (C16-18-alkyl methacrylate) P2-d
16 to 18-alkyl methacrylate in a 150-liter stirred vessel
(For example, Alfoll618S manufactured by Condea) Alcohol-based
4.889 kg, 44.0 kg of 100N oil and t-butyl
0.172 kg of peroctoate was added. CO_Two-By ice
After degassing, the mixture was heated to 85 ° C. Then within 3.5 hours C
51.111 kg of 16-18-alkyl methacrylate and t-butyl
Add 0.153 kg of chiller octoate using a metering pump
Added. Two hours after the addition, t-butyl perocte
0.112 kg was added. After 5 hours the polymerization stops
Was.

Molecular weight (GPC, PMMA standard) = 220,000 g / mol η_sp/ c (CHCl_Three, 20 ° C) = 44 ml / g Cloud point (in 0.1% isooctane) = -14 ° C Example 7 Preparation of poly (C12-18-alkyl methacrylate) P2-e
C12-18-alkyl methacrylate in a 150-liter stirred vessel
(Average carbon number is 14 and 18% branch. For example, Doban manufactured by Shell)
ol25L And a mixture of tallow alcohol
2.967 kg, 26.7 kg of 100N oil and t-butyl par
0.083 kg of octoate_TwoDegas with ice,
Heated to 85 ° C. Then C12-18-Al within 3.5 hours
37.033 kg of kill methacrylate and t-butyl peroc
0.0741 kg of toate was added. Two hours after addition, t
0.08 kg of butyl peroctoate was added. 5 hours later
Was further diluted with 33.3 kg of 100N oil.

Molecular weight (GPC, PMMA standard) = 410,000 g / mol η _sp / c (CHCl ₃ , 20 ° C.) = 65 ml / g Cloud point (in 0.1% isooctane) = <− 45 ° C. Example 8-12 10% solution in xylene As a polymer P1-a-P1-
e was added to crude oil at 80 ° C. All loadings are on a polymer basis. The pour point was measured according to DIN 51,597 by means of an automatic measuring device from the company Herzog, Lauda.
The pour point of Example 8 was determined according to DIN 51,597 (ASTM097-66).

These examples demonstrate that the mixture shows better effect than the simple substance.

Example 8 Indian crude oil, n-alkane content 23.4%, pour point before addition = 30 ° C flow improver = polymer 75 ppm 150 ppm P1-a +15 +21 P2-b +30 +30 P3 +30 +27 P1-a: P2-b = 1: 1 + 12 + 9 P1-a: P2-a = 2: 1 + 9 = 1: 1 + 12 + 6 = 1: 2 + 9 = 1: 3 + 9 Example 9 North Sea crude oil, n-alkane content 8.6%, before addition Pour point = 12 ° C. Flow improver = Polymer 4 ppm 8 ppm 16 ppm 30 ppm P1−a + 10 + 5 + 2−15 P2−d + 10 P1−a: P2−d = 1: 1−8 = 1: 4−7−8−16 = 1 : 9 +3 ± 0 -2 Example 10 Crude oil from the North Sea, n-alkane content 10.2%, pour point before addition = + 6 ° C Flow improver = polymer 10ppm 20ppm 500ppm P1-a-15-19 P2-c + 3 P2- d +6 +6 P2−e +6 P1−a: P2−c = 1: 1−20 −22 P1−a: P2−d = 1: 1−16−24 = 1: 4 −14 P1−a: P2−e = 1: 1-14 = 1: 4-8 Example 11 Crude oil from Pakistan, n-alkane content 23.6%, flow Point = + 19 ° C. flow improvers = polymer 250ppm 500ppm 1000ppm P1-a -7 P2 -a '-3 -11 -14 P1-a: P2-a' = 1: 1 -3 -11 -18 = 1: 4 - 7 -13 -18 = 1: 9 -9 -18 -18 Example 12 Crude oil from Pakistan, n-alkane content 23.0%, pour point = + 9 ° C. Flow improver = polymer 100 ppm P1-a-2 P2-a '+ 3 P1-a: P2-a '= 1: 1-5 = 1: 4-3 = 1: 9-2

Claims (3)

(57) [Claims] 1. In mineral oils and mineral oil products having improved flow properties comprising a group of crude oils, vacuum gas oils or resids containing long-chain polyalkyl (meth) acrylates, the long-chain polyalkyl (meth) acrylates A) Initiation of crystallization above 15 ° C (isooctane 0.1
(Measured as the cloud point of a 1% solution) Polyalkyl (meth) acrylates P1 and B) Temperature of the onset of crystallization of polyalkyl (meth) acrylate P1 and of crystallization with polyalkyl (meth) acrylate P2 Provided that the difference is at least 5 ° C,
Mineral oil and mineral oil products characterized by a mixture of polyalkyl (meth) acrylates P2 which starts crystallization at a temperature of 15 ° C. or lower. 2. The mineral oil mixture according to claim 1, wherein the weight ratio of the polyalkyl (meth) acrylate ranges from 1:50 to 50: 1, preferably from 1:10 to 10: 1. 3. The polyalkyl (meth) acrylate P1 is
Characterized in that it is constituted by acrylic acid esters of alkanols of C ₁₈ -C _24, claim 1 or 2 mineral oil mixture according.