JPH0459356B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a fuel oil composition with good low-temperature fluidity prepared from a heavy petroleum fraction and a low-temperature fluidity improver. As is well known, among the fractions obtained by distilling crude oil, those with a boiling point of approximately 150 to 450°C, called medium and heavy fractions, are used in large quantities as a source of various fuels such as kerosene, light oil, and heavy oil A. used for. Among these, especially light oil and A heavy oil, the fluidity may deteriorate significantly due to the precipitation of wax contained in the oil at low temperatures such as in winter, resulting in serious problems. For example, in order to prevent the wax contained in diesel oil from precipitating under cold conditions in winter, it is installed in a filter to prevent contaminants installed in the line that supplies diesel oil from the diesel tank to the engine. There have been cases where the fine screens have become clogged, making it impossible to supply light oil and causing the engine to stop, and furthermore, at low temperatures, the entire light oil has gelled and lost fluidity. In addition, similar wax precipitation causes poor combustion in the case of heavy oil A, which is used to drive the engines of fishing boats, heating machines for greenhouse cultivation, heating buildings, etc.
It may have a serious impact on human life and plants. [Prior art] In order to maintain the fluidity of fuel oil at low temperatures,
Various countermeasures have been taken in the past. For example, there are methods such as heating the fuel oil with hot water or an electric heater to keep it warm so that the drop in temperature does not directly cause a drop in the temperature of the fuel oil, but this requires equipment improvements and new energy costs. It is hard to say that this is an advantageous method. There is also a method of reducing the amount of wax precipitation by using kerosene fractions, which have excellent low-temperature fluidity even at relatively low temperatures, but relatively light fuel oils such as kerosene fractions Since the demand is large and the added value is high, it is difficult to say that it is a preferable method. Another known method for improving the low-temperature fluidity of fuel oil is to add a low-temperature fluidity improver. The action of the low-temperature fluidity improver affects the precipitation of wax from fuel oil, preventing the wax from growing to a gigantic size and stabilizing it with microcrystals. Various chemically synthesized products have been proposed as low-temperature fluidity improvers, but their effectiveness varies dramatically depending on the properties of the target fuel oil, and there is an urgent need to understand the properties of fuel oil to ensure stable quality control. However, this has been extremely difficult due to factors such as the large number of crude oil types and the complicated operating conditions of distillation equipment. In order to effectively express the effect of adding a low-temperature fluidity improver, several studies have been made on the properties of target fuel oil. For example, JP-A-58-134188 discloses medium distillate fuel oil.
100 parts by weight of ethylene copolymer and carbon number 26 or more
By adding 0.2 to 1.5 parts by weight of n-paraffin No. 27, low-temperature fluidity is improved. However, this method requires the addition of both ethylene copolymer and n-paraffin to the fuel oil.
In addition to complicating equipment and operations, n-
Since paraffin is actively added, the amount of wax deposited at low temperatures increases. As a result, the fluidity improver often does not work effectively. When used as fuel for diesel automobiles, which is a typical application, a strainer is installed in the middle of the fuel supply line, but due to the large amount of wax deposited, the wax saturation time in the strainer is shortened, causing early blockage. become,
This method cannot be said to be a preferable method. Furthermore, JP-A No. 61-58116 discloses a composition using a pour point depressant in light oil in which the amount of paraffin wax precipitated at -20 DEG C. is adjusted to 5.5 to 12% by weight. However, even if the amount of paraffin wax precipitated at -20℃ is specified to be in the range of 5.5 to 12% by weight, CFPP can be improved by adding a pour point depressant.
(low-temperature filtration clogging temperature) may not be lowered at all, or may only be lowered with a specific type of pour point depressant, so it cannot be said to be sufficient. [Problems to be solved by the invention] As described above, in the conventional technology, there are no additives that can improve the low-temperature fluidity of fuel oils with specific properties, and there are no additives that can improve the low-temperature fluidity of fuel oils with specific properties. Therefore, it is necessary to add a fairly large amount of specific substances other than additives, and it has been extremely difficult to provide a fuel oil with stably improved low-temperature fluidity. An object of the present invention is to provide a fuel oil with improved low-temperature fluidity that uses medium and/or heavy distillate oil of crude oil as a base oil in a large proportion. The object of the present invention is to optimize the amount of n-paraffin contained in medium and/or heavy distillate of crude oil so that the effect of the property improver can be fully exhibited. [Means for Solving the Problems] The present inventors have made extensive studies to solve the problems and have arrived at the present invention. That is, the present invention provides: (1) consisting of a large proportion of medium and/or heavy distillate oil of petroleum, containing n-paraffin having 25 or more carbon atoms;
The fuel base oil contains 0.1% by weight or more and less than 0.6% by weight, and the amount of wax that precipitates at a temperature 10°C lower than the cloud point is less than 4% by weight, an ethylene content of 60 to 80% by weight, and a number average molecular weight of 1000.
A fuel oil composition characterized by adding 30 to 1500 ppm of a copolymer of ethylene and a vinyl ester of a saturated carboxylic acid having a molecular weight distribution of 4.0 to 5000 and a molecular weight distribution of 4.0 or less, (2) contained in a fuel base oil. The fuel oil composition according to (1) above, in which n-paraffin having a carbon number of 25 or more is 0.2% by weight or more and less than 0.5% by weight, (3) the fuel according to (1) above, in which the vinyl ester of a saturated carboxylic acid is vinyl acetate. oil composition, (4) a copolymer of ethylene and vinyl acetate having an ethylene content of 60 to 75% by weight and a number average molecular weight of 1000;
4,000 to 4000, a molecular weight distribution of 4.0 or less, and having 6 or less methyl-terminated side chains per 100 methylene groups in the main chain in addition to the methyl group of the acetyl group. The medium and/or heavy distillate oil of petroleum used as a large proportion of base oil in the present invention is a distillate oil obtained by distilling crude oil, and has a boiling point of about 150.
It is a mixture of many components, mainly hydrocarbons, in the range of ~450°C. Fractions obtained from general petroleum distillation equipment include light gas oil and heavy gas oil obtained from atmospheric distillation equipment, or those obtained by hydrogenating these oils with a desulfurization equipment such as a unifier, or distillates from atmospheric distillation equipment. There are vacuum gas oils obtained by distilling residual oil under reduced pressure using a vacuum distillation apparatus, hydrogenated products thereof, and the like, and these may be blended as appropriate depending on the purpose. If necessary, a small amount of heavy oil generated from petroleum refining equipment, such as oil processed in catalytic cracking equipment or hydrocracking equipment, or residual oil dewaxed during lubricating oil production, may be mixed. No problem. Furthermore, normal pressure residual oil or vacuum residual oil, which is commonly used as a preparation method for A heavy oil,
Alternatively, a small amount of extract oil produced in the lubricating oil refining process may be mixed. In the present invention, the amount of n-paraffin having 25 or more carbon atoms contained in the medium and/or heavy distillate of petroleum as the base oil is analyzed by a conventional method using a temperature-programmed gas chromatograph. It is something. That is, using a column packed with a packing material consisting of a weakly polar distributing agent and a porous carrier, a trace amount of sample is analyzed using a flame ionization method and a detector, and n is determined from a chromatogram consisting of each separated component. −
This is to determine the paraffin content. For example, a column packing material commercially available from Wako Pure Chemical Industries, Ltd. (Silicon GE SE-30, 2%, 60/
A sample oil was injected into a column packed with a stainless steel tube with a diameter of 3 mm and a length of 4000 mm, and the temperature was raised from 70°C to 270°C at a rate of 5°C/min, and hydrogen was added. Detected using flame ionization method. The detected electrical signal is processed as an external output by a recorder or a data processor, and is obtained by determining the n-paraffin peak. In the present invention, the amount of n-paraffin having 25 or more carbon atoms contained in the medium and/or heavy distillate of petroleum as the base oil is preferably in the range of 0.1% by weight or more and less than 0.6% by weight. If the amount of n-paraffin having a carbon number of 25 or more is less than 0.1% by weight, the effect of improving the low-temperature filtration clogging temperature by the low-temperature fluidity improver will be poor, and
More than 0.6% by weight is an extremely large amount, e.g.
Although it may be possible to improve the clogging temperature of the low-temperature filter by adding 2000 ppm or more of a low-temperature fluidity improver, the total amount of precipitated wax may increase, resulting in a fuel oil that cannot be put to practical use. many. The preferred amount of n-paraffin having 25 or more carbon atoms is 0.2% by weight or more and less than 0.5% by weight, which can be further enhanced by the effect of adding a low-temperature fluidity improver. Within this range, the low-temperature filtration clogging temperature can be sufficiently lowered by adding a relatively small amount of the low-temperature fluidity improver. As an example of the low-temperature fluidity improver used in the present invention, the substances described on pages 192 to 195 of "New Edition Petroleum Product Additives" (edited and authored by Toshio Sakurai, published by Koshobo, July 1986) can be referred to. However, more specifically, Tokuko Sho No. 48-23165, Tokko Sho 55-33480, Tokko Sho No.
Examples include ethylene copolymers disclosed in No. 60-17399 and JP-A-59-136391. Examples of ethylene copolymers include those using one or more vinyl esters of saturated fatty acids such as vinyl acetate, vinyl propionate, and vinyl butyrate as comonomers, and these can be used as high molecular weight ethylene copolymers. It may be a low-molecular-weight product that is produced and decomposed by oxygen, peroxide, heat, or the like. In particular, ethylene copolymers have an ethylene content of 60 to 80% by weight, a number average molecular weight of 1000 to 5000 measured by vapor pressure equilibrium method, and a molecular weight distribution of 60 to 80% by weight.
A range of 4.0 or less is preferable. If the ethylene content is less than 60% by weight or more than 80% by weight, and the number average molecular weight is less than 1000 or more than 5000, the effect of improving the low temperature filtration clogging temperature will be somewhat poor, and a large amount will need to be added.
It is hard to say that it is economically advantageous. One type of ethylene copolymer may be used, or a mixture of two or more types may be used. Ethylene copolymer can be mixed and dissolved in fuel oil as it is, but industrially it is convenient to dissolve it in a hydrocarbon solvent and use it as a 10 to 90% by weight solution. Among the above ethylene copolymers, ethylene-vinyl acetate copolymers are particularly preferred because they are industrially easily available and have excellent effects on improving low-temperature fluidity. More preferably, the ethylene-vinyl acetate copolymer has an ethylene content of 60 to 75% by weight, a number average molecular weight of 1000 to 4000, a molecular weight distribution of 4.0 or less, and a main chain methylene group in addition to the methyl group of the acetyl group. It has 6 or less methyl-terminated side chains per 100 pieces, and can further reduce the clogging temperature of low-temperature filtration. The molecular weight distribution was determined using the gel permeation chromatography (GPC) method ["Polymer Measurement Methods, Structure and Physical Properties (Part 1)" edited by the Society of Polymer Science and Technology, Baifukan, published in 1972, Vol.
The method described on pages 76-89 is helpful. ] is determined from the ratio of weight average molecular weight (Mw)/number average molecular weight (Mn) in terms of standard polystyrene. Furthermore, in the present invention, the degree of branching is expressed as "the number of methyl-terminated side chains per 100 methylene groups in the main chain other than the methyl group of the acetoxy group," and is expressed by the nuclear magnetic resonance ( ¹ H NMR) method ("Journal of the Chemical Society of Japan" 1980). Year, 1st
The method described in No. 1, pp. 74-78 can be used as a reference. ) is calculated using the results obtained by That is, it is calculated by determining the peak ratio based on methyl groups and methylene groups in the proton nuclear magnetic resonance spectrum, and using the vinyl acetate content determined by the saponification method and the number average molecular weight determined by the vapor pressure osmotic pressure method. It is. Assuming that both ends of the main chain methylene group are methyl groups and all side chains are ethyl groups, the terminal methyl group 2
It is calculated by subtracting the number of individuals. The amount of the low temperature fluidity improver used in the present invention is:
The range is preferably from 30 to 1500 ppm, more preferably from 50 to 1000 ppm by weight, relative to the base oil consisting of medium and/or heavy fractions of petroleum. If the amount added is less than 30 ppm, little reduction in the clogging temperature of the low-temperature filtration can be expected;
If it exceeds 1500 ppm, it is not preferable because it is economically disadvantageous compared to the effect obtained. For the fuel oil composition according to the present invention, a rust inhibitor,
An antioxidant, an antistatic agent, a cetane number improver, an anticorrosion agent, or the like may be used in combination. [Examples] Hereinafter, the fuel oil composition of the present invention will be specifically explained using Examples, but the present invention is not limited by these descriptions. In addition, various analyzes and measurements of the sample oil used were performed by the following methods. Specific gravity JIS K2249 (1986) Kinematic viscosity JIS K2283 (1986) Distillation test JIS K2254 (1986) Cloud point JIS K2269 (1986) Pour point JIS K2269 (1986) CFPP (cold filtration clogging temperature) IP-309 Cold shown in (UK 1976)
Measured using an automatic low-temperature filtration clogging point tester "Model A4F2 manufactured by Yoshida Kagaku Kikai Co., Ltd." manufactured in accordance with Filter Plugging Point of Distillate Fuele Amount of wax precipitation Commercially available from Sumitomo Chemical Co., Ltd. in 50 g of sample oil Dissolve 200 ppm of the low-temperature fluidity improver "Stabinol (registered trademark) FI-18" and heat the mixture at -5°C from room temperature at a rate of 1°C/hr in a 100ml graduated cylinder.
℃, -10℃, or 10℃ below cloud point. The oil content other than the wax content precipitated from the cooled sample oil is discharged under reduced pressure through a filter fitting equipped with a 5 μm membrane filter, and 50 ml of cold ethanol/ethyl ether (2/1 volume ratio) is added to the remaining wax content, and stirred lightly. After that, drain the oil under reduced pressure again. Furthermore, 50ml of cold methanol was added to the remaining wax, and the entire amount was poured into a 11G4 glass filter to remove the oil under reduced pressure.The wax remaining in the glass filter was air-dried for a day and night, and the weight of the wax was measured to determine the amount of wax deposited. shall be. N-paraffin content Gas chromatograph GC- manufactured by Shimadzu Corporation
The n-paraffin content in the sample oil was determined using Model 9A and Chromatopack C-R2AX data processor. Note that n-triacontane was used as an internal standard substance for quantitative determination. The main operating conditions are shown below. Column: Stainless steel, inner diameter 3 mm, length 4 m Column packing material: Silicone GE SE manufactured by Wako Pure Chemical Industries, Ltd.
-30, 2%, 60/80 mesh (Uniport HP
Carrier) Injection temperature: 270°C Carrier gas: Helium Detector: Flame ionization (FID) Column heating rate: 5°C/min (70 → 270°C) Example 1 Diesel whose properties are shown in Tables 1 and 2 To light oil samples No. 1 to No. 4, 500 ppm of a low temperature fluidity improver made of a 50% by weight solution of various low temperature fluidity improvers shown in Table 3 in xylene was added, and CFPP
was measured. Temperature drop from CFPP of sample oil itself (△CFPP)
Table 3 shows the results of examining the effectiveness of the effects.

【table】

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【table】

[Table] Example 2 Diesel gas oil samples shown in Tables 4 and 5
Capacity ratio of No. 5 and No. 9 is 75/25 (sample No. 6), 50/50
(Sample No. 7) and 25/75 (Sample No. 8). The properties of the mixed sample oil are also shown in Tables 4 and 5.
Shown in the table. This sample oil had a vinyl acetate content of 36.5% by weight,
60% by weight xylene solution of ethylene-vinyl acetate copolymer with number average molecular weight 1690, molecular weight distribution 2.4, 3.8 methyl-terminated side chains/100 methinelene (Additive A)
was added at 300 or 500 ppm and CFPP was measured. Table 6 and Figure 2 show the results of examining the effectiveness of the effect using the temperature drop (ΔCFPP) from the sample oil itself.

【table】

【table】

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[Table] * Figure 1 shows the gas chromatogram of sample oil No. 5.

[Table] Example 3 Additive A used in Example 2 was added at 500 ppm to the fuel oil samples shown in Table 7, and CFPP was measured. Temperature drop from CFPP of sample oil itself (ΔCFPP)
The results of examining the effectiveness of the effects are shown in Table 7 and in Figure 2. Furthermore, the results using Additive B and Additive C for comparison are also listed in Table 7, and are shown in FIGS. 3 and 4, respectively.

【table】

[Table] [Effects of the invention] As is clear from the above examples, the number of carbon atoms is 25.
The n-paraffin content is less than 0.1% by weight or 0.6% by weight or more, and the cloud point is 10% or more.
For sample oils in which the amount of wax precipitated at low temperatures was 4% by weight or more, it was not possible to reduce CFPP by adding a low-temperature fluidity improver, but when the n-paraffin content was 0.1% by weight, % or more and less than 0.6% by weight, and the amount of wax that precipitates at a temperature 10°C lower than the cloud point is 4% by weight.
Especially in sample oils that are less than
Remarkable effects were obtained for sample oils containing 0.2% by weight or more and less than 0.5% by weight. Also, as a low-temperature fluidity improver, it is especially suitable for use with an ethylene content of 60 to 75% by weight and a number average molecular weight of 1000.
When using an ethylene-vinyl acetate copolymer of
A more significant effect was obtained when the ratio was 4.0 or less and the number of methyl-terminated side chains was 6/100 methylene or less.

[Brief explanation of the drawing]

Figure 1 shows sample oil obtained by the gas chromatography n-paraffin analysis method shown in the example.
This is the gas chromatogram of No. 5, and the portion calculated as n-paraffin is shown with diagonal lines. Figure 2 shows the content of n-paraffin having 25 or more carbon atoms in various sample oils and the xylene 60% solution of an ethylene-vinyl acetate copolymer with a vinyl acetate content of 36.5% and a number average molecular weight of 1690 (additives). A) Shows the relationship between the temperature at which the low temperature filtration clogging temperature drops (ΔCFPP) when 500 ppm is added. Figure 3 shows the content of n-paraffin having 25 or more carbon atoms in each sample oil, and the xylene 60% solution of an ethylene-vinyl acetate copolymer with a vinyl acetate content of 16.5% and a number average molecular weight of 2200 (additives). B) Shows the relationship between the low temperature filtration clogging temperature drop temperature (ΔCFPP) when 500 ppm is added. Figure 4 shows the n-paraffin content with carbon numbers of 25 or more in each sample oil and the vinyl acetate content of 44.6
60% by weight solution of ethylene-vinyl acetate copolymer with a number average molecular weight of 1820 in xylene (Additive C)
The relationship between the temperature at which the low-temperature filtration clogging temperature drops (ΔCFPP) when 500 ppm is added is shown.

Claims (1)

[Claims] 1. Consisting of a large proportion of medium and/or heavy distillate oil of petroleum, containing n-paraffin having 25 or more carbon atoms.
The fuel base oil contains 0.1% by weight or more and less than 0.6% by weight, and the amount of wax that precipitates at a temperature 10°C lower than the cloud point is less than 4% by weight, an ethylene content of 60 to 80% by weight, and a number average molecular weight of 1000. No
5000, a fuel oil composition comprising 30 to 1500 ppm of a copolymer of ethylene and a vinyl ester of a saturated carboxylic acid having a molecular weight distribution of 4.0 or less. 2. The fuel oil composition according to claim 1, wherein the fuel base oil contains 0.2% by weight or more and less than 0.5% by weight of n-paraffin having 25 or more carbon atoms. 3. The fuel oil composition according to claim 1, wherein the vinyl ester of a saturated carboxylic acid is vinyl acetate. 4. The copolymer of ethylene and vinyl acetate has an ethylene content of 60 to 75% by weight, a number average molecular weight of 1000 to 4000, a molecular weight distribution of 4.0 or less, and 6 or less per 100 methylene groups in the main chain in addition to the methyl groups of acetyl groups. A fuel oil composition according to claim 3 having a methyl-terminated side chain of.