JPH0353354B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Field of Application) The present invention relates to a method for improving the cold flow properties of fuel oil prepared from medium and heavy fractions of petroleum. As is well known, when fuel oils such as light oil and heavy oil, which are medium and heavy fractions of petroleum, are exposed to low temperatures, their fluidity decreases significantly due to the precipitation of paraffin wax contained therein, causing serious problems. This may cause problems. For example, when the temperature drops in winter, the paraffin wax contained in diesel oil precipitates, causing many operational problems in diesel engines such as clogging of oil pipes and filters installed in the fuel supply system of internal combustion engines. There is a case. Furthermore, when heavy oil reaches low temperatures, it loses its fluidity due to the precipitation of paraffin wax, making it impossible to transport or making it difficult to burn in a burner. On the other hand, in recent years, despite the tendency for imported crude oil to become heavier, the demand ratio for distillate fuels such as kerosene, light oil, and A-heavy oil has tended to increase. Therefore, in order to obtain as much fuel oil as possible from heavy crude oil containing a large amount of paraffin wax with a large molecular weight through distillation fractionation, it is necessary to deep-cut the crude oil to extract even the high-boiling fraction. As a result, the content of high-molecular-weight paraffin wax in fuel oil increases, and the low-temperature fluidity tends to decrease further, so it has become essential to find some way to improve the low-temperature fluidity. (Prior Art) Many fluidity improvers have been disclosed for the purpose of solving these problems, and representative examples include ethylene-vinyl acetate copolymer (US Pat. No. 3,048,479), ethylene - Acrylic acid ester copolymer (US Pat. No. 2,604,453), alkyl (meth)acrylate polymer (US Pat. No. 2,091,627)
), condensates of chlorinated paraffins and naphthalene (US Patent No. 1815022), nitrogen-containing derivatives of alkenylsuccinic acids (US Patent No. 3444082), copolymers of ethylenically unsaturated dicarboxylic acids and α-olefins (Japanese Unexamined Patent Publication No. 157106/1983), ethylene and α
- copolymers with olefins (Japanese Patent Publication No. 4202/1983) and the like. (Problem to be solved) These fluidity improvers are tested by pour point test (JISK-
2269), all of them show a good pour point lowering effect, but the cold filter plugging point (Cold
(Filter Plugging Point) tests are often not sufficiently effective. In particular, there are few that are effective against fuel oil containing a large amount of high molecular weight paraffin wax. Pour point tests cannot predict blockage of filters in the fuel supply line due to paraffin wax crystal particles that precipitate at temperatures significantly higher than the pour point; however, cold filter plugging point (CFPP) , the measurement method is
The test (described later as the CFPP method) is intended to predict such phenomena, and is currently a widely used test method. (Means for Solving the Problems) The present inventors have conducted extensive research to improve the drawbacks of CFPP, a conventionally used fluidity improver, as described above, and as a result, they have arrived at the present invention. That is, the gist of the present invention is to improve low-temperature fluidity by adding one or more conventionally used low-temperature fluidity improvers (A) to fuel oil. One or more fluidity improving aids (B) selected from the group of (B-1) to (B-4) are added to the agent (A) in an amount of 0.01 to 0.01 to
A method for improving low-temperature fluidity of fuel oil, characterized by adding 50 parts by weight. (B-1) Aliphatic saturated monohydric alcohols represented by the general formula C _o H _2o+1 OH, where n is a number from 1 to 8 (B-2) Represented by the general formula C _o H _2o (OH) ₂ aliphatic saturated dihydric alcohols, where n: number of 3 to 8 (B-3) oxyalkylene glycols represented by the general formula H(OA) _x OH, where A: C ₂ to C ₄ alkylene group, x;
Number of 1 to 7 (B-4) Oxyalkylene glycol monoalkyl ethers represented by the general formula R (OA) _Y OH, where A: C ₂ to _{C 4} alkylene group, Y;
A number from 1 to 5, R: a _C1 to _C4 alkyl group. Among the fluidity improving aids (B) that can be used in the present invention,
The aliphatic saturated monohydric alcohols selected from the group (B-1) include methanol, ethanol, n
-Propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tertiary-butanol, n-aluminum alcohol, isoamyl alcohol, n-hexanol, 2-ethylbutanol, n-heptanol, n-octanol, 2
-Ethylhexanol and the like, preferably _C3 to _C5 alcohols and mixtures thereof are used. The aliphatic saturated dihydric alcohols selected from the group (B-2) include trimethylene glycol,
Examples include butanediol, 1,5-pentanediol, hexylene glycol, octylene glycol, etc., but preferred are _C3 to _C6 dihydric alcohols and mixtures thereof. Examples of the oxyalkylene glycol (B-3) include ethylene glycol, diethylene glycol, triethylene glycol, polyoxyethylene glycol (average molecular weight 300 or less), propylene glycol, dipropylene glycol, tripropylene glycol, polyoxypropylene glycol (average molecular weight 300 or less), polyoxyethylene/polyoxypropylene random glycol (average molecular weight 300 or less), and mixtures thereof. A high molecular weight of 300 or more is not preferable because it becomes difficult to dissolve in fuel oil. Examples of the oxyalkylene glycol monoalkyl ether (B-4) include cellosolves such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether; carbitols such as diethylene glycol monomethyl ether and diethylene glycol monobutyl ether; and triethylene Glycol monomethyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, pentaethylene glycol monomethyl ether, tri(oxyethylene/oxypropylene 1:1 random copolymerization) glycol monobutyl ether, ditetraethylene glycol monobutyl ether, etc. A mixture can be mentioned. That is, the fluidity improving aid (B) of the present invention is selected from alcohols, glycols, and ethers having one or more and two or less hydroxyl groups in the molecule.
Among (B-1) to (B-4), preferably (B-
2), (B-3), and (B-4), (B-4) is most preferably used. Regarding the conventionally used fluidity improver (A), which is another factor of the present invention, the following can be used, but the examples are not limited to these. Ethylene-vinyl acetate copolymers include those with a relatively low molecular weight of 10,000 or less,
The vinyl acetate content can range widely from 5 to 60% by weight, but preferably has a molecular weight of 1000 to 60%.
5000 with a vinyl acetate content of 20-50% by weight. Examples of the ethylene-acrylic ester copolymer include those having a molecular weight of 30,000 or less, and those having an acrylic ester content ranging from 10 to 80% by weight can be used. Furthermore, the acrylic esters can range from relatively lower alkyl esters such as methyl acrylate and ethyl acrylate to higher alkyl esters such as octyl acrylate and octadecyl acrylate. Suitable ones have a molecular weight of 1000 to 6000 and an acrylic acid ester content of 30 to 60% by weight, and examples of the acrylic ester include lower (C ₁ to _{C 4} ) alkyl acrylates such as methyl acrylate and ethyl acrylate. It is. Examples of the alkyl (meth)acrylate polymer include methacrylate or acrylate homopolymers or copolymers (molecular weight 1000 to 1000000) having a wide range of _C1 to _C22 alkyl groups. Preferred are polymers containing a large proportion (for example 80% by weight or more) of methacrylates or acrylates with _C12 to _C18 alkyl groups, the molecular weight of which is in the range 5000 to 200000. Examples of condensates of chlorinated paraffins and naphthalene include condensates of chlorinated paraffins of C ₈ or more and naphthalene. Its molecular weight is usually
20,000 or less, preferably 2,000 to 8,000. As a nitrogen-containing derivative of alkenylsuccinic acid,
It is obtained by reacting an alkenylsuccinic acid or its anhydride containing a C ₄ to _{C 28} alkenyl group with a mono- or dialkylamine or a polyalkylene polyamine, and preferably contains a C ₁₀ to C ₂₂ alkenyl group. It is a reaction product of alkenylsuccinic acid or its anhydride and a dialkylamine containing two _C12 to _C22 alkyl groups. The copolymer of ethylenically unsaturated dicarboxylic acid and α-olefin has a molecular weight of 5,000 to 50,000, preferably 7,000 to 7,000, obtained by reacting maleic anhydride with α-olefin having 20 to 60 carbon atoms per molecule. It is a copolymer of 20,000. In addition, as a copolymer of ethylene and α-olefin, it is a copolymer with a molecular weight of 1,000 to 50,000 obtained by reacting 1 mole of linear C ₁₀ to _{C 22} α-olefin with 1.1 to 30 moles of ethylene. Yes, preferably 3 to 3 ethylene per 1 mole of dodecene-1
It is a copolymer with a molecular weight of 2000 to 3000 made by reacting 20 moles. These fluidity improvers (A) are usually contained in fuel oil.
It is added in an amount of 0.001 to 1.0% by weight, preferably 0.01 to 0.1% by weight, and can be used alone or as a mixture. In addition, the fluidity improving aid (B) selected from groups (B-1) to (B-4) is different from the fluidity improving agent (A).
It is added in an amount of 0.01 to 50 parts by weight, preferably 0.1 to 10 parts by weight, and can be used alone or as a mixture. If the amount of the fluidity improving aid added is less than 0.01 part by weight, the addition effect can only be expected within the error range, and if it is added in excess of 50 parts by weight, the effect will not improve any further, which is economically disadvantageous. This is not desirable. The fuel oil in the present invention is a petroleum product that is mainly used as a fuel. Specific examples include distillate fuel oil, residual oil, and mixed fuel oil, with distillate fuel oil being preferred. Distillate fuel oils include gasoline (automobile gasoline, aviation gasoline), kerosene (No. 1, No. 2), light oil (Special No. 1, No. 1, No. 2, No. 3, and Special No. 3), and heavy oil (A heavy oil, B heavy oil). Among these, preferred are light oil and A heavy oil. (Effect of the invention) By adding the fluidity improving aid (B) of the present invention and the fluidity improving agent (A) that has been used conventionally to fuel oil, it is possible to simply lower the pour point of the fuel oil. This makes it possible to significantly reduce CFPP, which makes it possible to solve various problems related to low-temperature fluidity during storage and transportation of fuel oil with a relatively high boiling point that contains a large amount of paraffin wax. Therefore, even high-boiling fractions can be used, making it possible to increase the production amount of high-quality fuel oil. The mechanism of action of the fluidity improving effect of the present invention is not clear, but since it has a particularly excellent effect on reducing CFPP, the fluidity improver (A ) and fluidity improving aid (B) are not used, the crystal particles adhere to each other to form a three-dimensional network structure, which absorbs a large amount of oil and loses fluidity. By adding fluidity improver (A),
Pour point tests (JISK-2269) are conducted to refine the wax crystals by precipitating these as crystal nuclei in the paraffin wax and creating numerous nucleation points.
However, because the crystal particles are strong, crystals larger than the pore size of the 350 mesh (44μ) filter block the pores, resulting in insufficient pour point reduction.
I can't get CFPP. On the other hand, by using the fluidity improving aid (B) of the present invention in combination, the crystal grains of the paraffin wax can be further refined, the strength of the crystal grains can be weakened, and the shear stress applied when passing through a filter can be easily applied. It is thought that the crystals are destroyed, the filter passageability is improved, and CFPP is significantly improved. Furthermore, by using the fluidity improving aid (B) of the present invention, water contained in the fuel oil or mixed in from the outside can be dissolved and dispersed in the fuel oil and burned together with the fuel to be removed. This also makes it possible to avoid corrosion of metal materials such as fuel tanks and oil pipes due to water accumulation, and the problem of clogging of oil pipes and filters due to freezing of water. In the fluidity improving method of the present invention, the method of incorporating the fluidity improving aid (B) and the conventionally used fluidity improver (A) into fuel oil is not particularly limited. For example, a method in which the fluidity improving aid (B) and the fluidity improver (A) are added to fuel oil as they are. There is a method in which the fluidity improving aid (B) and the fluidity improver (A) are diluted with a solvent such as fuel oil or an aromatic hydrocarbon solvent and then added. In addition, the fluidity improving method of the present invention can be used in combination with additives such as rust preventives, antioxidants, and antistatic agents that are normally added to fuel oil, or in combination with other fluidity improvers as necessary. You may. The present invention will be further explained below with reference to Examples, but the present invention is not limited thereto. Examples and Comparative Examples As fuel oil, commercially available No. 1 diesel oil, No. 2 diesel oil, and A heavy oil, conventionally used fluidity improvers (A) shown by abbreviations A to F and fluidity improvers (A) shown by abbreviations a to i Tables 1 and 2 show the results of examining the low-temperature fluidity with the addition of the property improving aid (B), and as comparative examples,
Table 3 shows the results of adding the substance indicated by q. In addition, the pour point of low temperature fluidity is JIS K-2269.
(hereinafter abbreviated as PP), and CFPP was measured according to the following. <CFPP method> This is a method developed by Etsuso Co., Ltd. to evaluate the low-temperature fluidity of oil. When oil is cooled, the fluidity decreases due to precipitated paraffin wax, which is used as an index for filterability. This method is expressed in terms of the temperature of the oil when it takes a specified amount of time to pass through the water.A glass test tube covered with a stainless steel tube is immersed in a dry ice bath kept at -34℃, and 45 ml of the sample is poured into it. Insert a glass pipette with a 350 mesh (pore diameter 44 μ) stainless steel mesh (filter) at the tip into the sample, aspirate the sample into the pipette under reduced pressure of 200 mm H ₂ O column, and remove the sample (20 ml). ) is expressed as the CFPP value by the oil temperature until it takes 60 seconds for the pipette to rise to the specified scale. this
The lower the CFPP value (temperature), the lower the temperature at which filter clogging occurs, that is, the better the low-temperature fluidity. In the present invention, "filter clogging point tester"
The measurement was carried out using a commercially available device (manufacturer: Yoshida Scientific Instruments Co., Ltd.). Fluidity improver (A) A; Molecular weight of ethylene-vinyl acetate copolymer; 2500 Vinyl acetate content; 35% by weight B; Molecular weight of ethylene-acrylic ester copolymer; 3000 Content of acrylic ester; 40% by weight C ; Molecular weight of condensate of monochlorinated paraffin and naphthalene; 5000 D; Alkenylsuccinic acid amide; Reaction product of n-tetradecenylsuccinic acid and di(n-octadecyl)amine; F; Ethylenically unsaturated dicarboxylic acid and α- Copolymer with olefin Copolymer of maleic anhydride and C ₂₈ to C ₅₈ α-olefin Molecular weight: 12000 F; Copolymer of ethylene and α-olefin Dodecene-1 1 mol and 10 mol of ethylene Copolymer molecular weight: 2500 Below, indicated by abbreviations A to F. The fluidity improving aid (B) is indicated by the following abbreviations a to i. a; triethylene glycol monomethyl ether b; ethylene glycol c; hexylene glycol d; isopropanol e; polyoxypropylene glycol (average molecular weight 200) f; methanol g; n-octanol h; diethylene glycol monoethyl ether i; polyoxyethylene glycol (average molecular weight
200) In addition, as comparative examples, those with abbreviations j to q were added. j; nonyl alcohol k; n-dodecyl alcohol l; allyl carbinol m; benzyl alcohol n; 3-butene-1,2-diol o; glycerin p; diethylene glycol diethyl ether q; diethylene glycol acetate It can be seen that when the fluidity improving aid (B) of the present invention is used in combination with the fluidity improver (A) used, the fluidity of fuel oil, especially CFPP, is significantly reduced. Furthermore, from the results in Table 2, the appropriate amount of the fluidity improving aid (B) of the present invention is 0.01 to 50 parts by weight relative to the conventionally used fluidity improving agent (A). I understand. On the other hand, from the results in Table 3, it can be seen that substances other than the fluidity improving aid (B) of the present invention have almost no effect on improving fluidity.

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Claims (1)

[Claims] 1. When adding one or more conventionally used low-temperature fluidity improvers (A) to fuel oil to improve low-temperature fluidity, the low-temperature fluidity improver (A)
0.01 of one or more fluidity improving aids (B) selected from the group of (B-1) to (B-4).
A method for improving low-temperature fluidity of fuel oil, characterized by adding ~50 parts by weight. (B-1) Aliphatic saturated monohydric alcohols represented by the general formula C _o H _2o+1 OH, where n is a number from 1 to 8 (B-2) Represented by the general formula C _o H _2o (OH) ₂ aliphatic saturated dihydric alcohols, where n: number of 3 to 8 (B-3) oxyalkylene glycols represented by the general formula H(OA) _x OH, where A: C ₂ to C ₄ alkylene group, x;
Number of 1 to 7 (B-4) Oxyalkylene glycol monoalkyl ethers represented by the general formula R (OA) _Y OH, where A: C ₂ to _{C 4} alkylene group, Y;
A number of 1 to 5, R; a _C1 to _C4 alkyl group.