JPS61287985A - Method of improving low-temperature flowability of fuel oil - Google Patents

Abstract

PURPOSE:To effectively improve the low-temp. flowability even with respect to a fuel oil contg. a large amount of n-paraffin and a fuel oil having a remarkably narrow boiling range, by adding a specific ethylene-ethylenically unsatd. ester copolymer to a fuel oil comprising a medium and/or heavy fraction in a petroleum. CONSTITUTION:An ethylene-ethylenically unsatd. ester copolymer having an ethylenically unsatd. ester monomer content of 5-50wt%, a number-average MW of 800-2,900 and an MW distribution of 4.0 or less is added to a fuel oil comprising a medium and/or heavy fraction as main components in an amount of 10-2,000ppm. With respect to the degree of branching, it is preferred that the copolymer have 6 or less side chains having a methyl terminal per 100 methylene groups of the main chain, besides the methyl group of the ester group. Preferred ethylenically unsatd. ester is vinyl acetate.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for improving the low-temperature fluidity of fuel oil prepared from nine heavy fractions of petroleum. Among the distillates obtained through this process, the distillate with a boiling point of about 150 to 450°C, called the middle-heavy fraction, is used in large quantities as kerosene, light oil, A2]i oil, etc. for various fuel sources. There is.

Among these, especially light oil and A heavy oil, the fluidity may deteriorate significantly due to the precipitation of wax contained in the oil under low temperature conditions such as in winter, which may cause serious problems. For example, due to precipitation of wax contained in diesel oil under cold conditions in winter, diesel engine K k
i. In cases where the fine screen built into the filter for preventing foreign substances installed in the middle of the oil supply line becomes clogged and fuel oil cannot be supplied, or when the temperature is low. There are many cases where the fuel oil itself becomes gelled and loses its fluidity completely, making diesel engines unable to operate. In addition, there are many cases where the fuel oil itself becomes gelled and loses its fluidity, making diesel engines unable to operate.
In the case of heavy oil A used for heating buildings, etc., similar wax precipitation can cause combustion failure, which can have a serious impact on human life and property.

The present invention relates to a method for improving the low-temperature fluidity of these fuel oils. [Prior Art] Conventionally, various measures have been taken for the purpose of improving the fluidity of fuel oils at low temperatures. There are methods such as insulation and heating that will prevent the decrease in 9C temperature from directly causing a decrease in the temperature of the fuel oil, but this will require equipment improvements and new energy costs. There is also a method of mixing and diluting superior kerosene distillates to reduce the amount of wax deposited.However, relatively light oils such as kerosene distillates are in high demand and are essential to civil life. Therefore, it cannot be said to be a preferable method.

In addition, in terms of crude oil, which can be said to be the raw material for fuel oil, imported crude oil has tended to become heavier in recent years due to the policies of oil-producing countries to conserve light crude oil and the relatively high proportion of heavy crude oil in new deep oil fields. On the other hand, given the increasing need for light distillates, from the perspective of effective use of petroleum resources, effective measures are needed to produce larger amounts of light distillates such as light oil and Al oil. has become essential.

As another method aimed at improving the cold flow properties of fuel oil,
There is a method of adding a fluidity improver. Most fluidity improvers are chemically synthesized products, and their role is to act when the wax content in fuel oil precipitates at low temperatures. In addition to preventing the wax from becoming large and stabilizing it as microcrystals, it also aims to improve its fluidity.

Many types of fluidity improvers have been proposed, and they have actually been added to fuel oil with great improvement effects.
Typical fluidity improvers include copolymers of ethylene and unsaturated esters, polymers of (meth)acrylic acid esters, addition of maleic anhydride to α-olefins, or copolymerized alkenyl esters. Examples include amidates and salts synthesized from succinic anhydride and long-chain alkyl amines, and ester compounds having a long-chain alkyl group.

Among them, vinyl esters of ethylene and saturated carboxylic acids
Many examples have been proposed using copolymers with. For example, Special Publication No. 1989-20069, Special Publication No. 48-2816
No. 5, JP-A-56-141890, JP-A-58-12
No. 9096, JP-A-59-8789, JP-A-59-1
Among the copolymers mentioned above, ethylene-vinyl acetate copolymers, which are described in Japanese Patent No. 86891, not only lower the pour point of normal fuel oil but also lower the temperature of one-lower-temperature filtration t, b. Due to its excellent action, the amount used has been rapidly increasing in recent years◇ [Problem to be solved by the invention] However, with these fluidity improvers, t-para 74
It is difficult to act sufficiently on fuel oils that contain a large amount of carbon dioxide or have a very narrow boiling point range, and even though it is relatively expensive, it requires a large amount of addition.
The results were not necessarily satisfactory, and improvements were desired. The purpose of the present invention is to provide a good effect on fuel oils that contain a large amount of p-paraffin and fuel oils that have a very narrow boiling point range. The object of the present invention is to provide a method for improving low-temperature fluidity.

Another objective is to provide a fluidity improver that is effective even when added in small amounts to fuel oils that contain a large amount of 1-buffine or have a very narrow boiling point range. 0 [Means for solving the problem] The present inventors have arrived at the present invention as a result of intensive studies to solve the problem. In other words, the present invention has the following:
A fuel oil consisting of a small proportion of medium and/or heavy fractions of petroleum containing an ethylenically unsaturated ester μ monomer ftt5~
Alethylene-ethylenically unsaturated ester copolymer (hereinafter referred to as ethylene copolymer) with a number average molecular weight of 800 to 2,900 and a molecular weight distribution of 4 or less, 50 to
The present invention provides a method for improving the low-temperature fluidity of fuel oil characterized by adding 2,000 ppm of ethylene copolymer in the main chain in addition to the methyl group of the ester group. An improved method characterized in that the method has 6 or less methyl-terminated side chains (hereinafter referred to as the degree of branching) per 100 methylene groups, and the ethylenically unsaturated ester is vinyl acetate μ. 〇 According to the present invention, when the ethylenically unsaturated ester monomer is vinyl acetate, its content is determined by the saponification method The method described in ) is a reference].
The content of other monomers can be determined by infrared spectroscopy [the method described in "Polymer Measurement Methods, Structure and Physical Properties (G)" edited by the Society of Polymer Science and Technology, published by Baifukan in 1971, pp. 8-71 is used as a reference. ◎ In addition, the number average molecular weight is determined by the vapor pressure osmotic pressure method [described in "Polymer Measurement Methods, Structures and Things! 1: Yama", Polymer Science Society of Japan, published by Baifukan in 1971, pp. 67-75. The molecular weight distribution is determined by the gel permeation chromatography (GPC) method ["Polymer Measurement Methods, Structures and Physical Properties" published by the Society of Polymer Science and Technology, Volume 76, published by Baifukan in 1972]. 8
The method described on page 9 is a reference] to calculate the weight average molecule ffi (iw) / number average molecule I in terms of standard polystyrene.
In addition, in the present invention, the degree of branching is expressed as "the number of methyl terminal side chains per 100 main chain methylene groups other than the methyl group of the ester group", and is Resonance ('HNMR) method ('Journal of the Chemical Society of Japan J
1980.

No. 1, pages 74 to 78 (for reference)) is used as the result ft.

That is, the peak ratio of about 0.85 ppm and about 1.45 ppm in the proton nuclear magnetic resonance spectrum μ was determined, and the ethylenically unsaturated ester monomer content and the number average determined by vapor pressure osmosis method were determined. It is calculated using the molecular weight (0 (both ends of the main chain methylene group are methyl groups), and all side chains are ethyl groups, and is calculated by subtracting the two terminal methyl groups. 〇The present invention will be explained in detail below◎ The medium and/or heavy oil fraction of petroleum used in the present invention is a distillate obtained by distilling crude oil under normal pressure or under reduced pressure. Distillate oil with ◎ having a converted boiling point in the range of about 180 to 450°C is a non-distillate oil obtained as it is, mixed in an appropriate ratio, or by distillation under normal pressure or reduced pressure if necessary. By mixing a small amount of (distillation pot residual oil), the Japanese Industrial Standard (JIS) number is OK220.
It is commercially available as K2204 (oil repellent), K2204 (light oil), K2205 (heavy oil), Type 1 (A heavy oil), etc.

The various ethylene copolymers used in the present invention can be produced by known methods. For example, it can be produced by free radical bulk polymerization, emulsion polymerization, or solution polymerization.Among these, the free radical bulk polymerization method has the advantage of being able to be produced without using a large amount of solvent.This method requires a continuous high-pressure polymerization equipment. Pressure 500~4.0
00, free radical group-forming polymerization catalysts under temperature conditions of 100 to 800°C, such as azo catalysts such as α·-17zobisisobutyronitrile, tertiary butyl peroxypivalate, tertiary butyl peroxypivalate, and tertiary butyl peroxypivalate. <-oxy 2-ethylhexanoate, di-tert-butyl peroxide, hydrogen peroxide, diethyl peroxide,
and citric acid.

Propane, butane, propylene, butene using peroxygen type polymerization catalysts such as alkali metal, alkaline earth metal or ammonium persulfates.

Propionaldehyde, methyl ethyl ketone.

Tetofhydrofufun, η-butyl μdehyde.

This is a method in which ethylene and other comonomers are t-coffi-merged in the presence of a polymerization regulator such as acetone, cyclohexane, methylcyclohexane, cyclohexanone, heptane, or the like.

Comonomers of ethylenically unsaturated esters copolymerized with ethylene include vinyl acetate, vinyl propionate,
Fatty acid vinyl esters such as vinyl butyrate, vinyl octanoate, and vinyl stearate, or methyl acrylate, methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, and butyl methacrylate.

Octyl acrylate/L/, octyl methacrylate.

Dodecyl acrylic acid, dodecyl methacrylate.

Examples include acrylic acid esters such as acrylic acid stearic acid /L/, methacrylic acid stearic acid y, etc., ethylenically unsaturated acids such as methacrylic acid esters, and alkyl esters of boronic acids, and one or more of them may be used.

One type of ethylene copolymer used in the present invention is 4 types,
It may also be used in combination or in a mixture with products whose physical properties have been changed by changing manufacturing conditions.

Among the above-mentioned ethylene copolymers, these are easily available industrially, and from the viewpoint of price and improvement of low-temperature fluidity,
Ethylene-vinyl acetate copolymer is particularly preferred.

Comonomer content of the ethylene copolymer used in the present invention,
Physical properties such as number average molecular weight, molecular weight distribution, degree of branching, etc. depend on polymerization conditions, such as reaction pressure, temperature, amount of catalyst, type and amount of fi-coupling agent, type and amount of comonomer, average residence time in the reactor, etc. A desired value can be obtained by selecting appropriately. Furthermore, characteristic ethylene copolymers can be obtained by changing the shape of the reactor, such as a seed reactor with or without internal partitions, a tube reactor, etc. Comonomer content is 5 to 50% by weight % range is suitable, and a range of 15 to 40% by weight is particularly preferable. ◎More preferably 20 to 801%! The amount ranges from % to %. Comonomer content is less than 5% by weight or 60% by weight
If the amount is too large, the solubility may be poor and sedimentation may occur when mixed with fuel oil.Also, a large amount of addition is required to obtain sufficient low-temperature fluidity effect, which is undesirable. The molecular weight is preferably in the range of 800 to 2,900. The number average molecular weight is lower than 800 or 2.90.
If it is larger than 0, it will be difficult to act sufficiently on wax precipitated from fuel oil, and the effect of improving low-temperature fluidity will be poor.

The molecular weight distribution is preferably 4 or less. Molecular weight distribution is 4
If the diameter is too large, the proportion of components that do not act on the wax precipitated from the fuel oil will be high, and the effect of improving low-temperature fluidity will be poor if the ethylene copolymer has a molecular weight distribution of 4 or less.

The degree of branching is usually 16 or less, particularly preferably 6 or less. The greater the degree of branching, the weaker the effect of keeping the wax precipitated from fuel oil in a fine state, resulting in the poorer low-temperature fluidity improvement effect. The range of 10 to 2,000 ppm by weight is appropriate for fuel oil consisting of high quality and/or heavy oil fractions, and preferably about 80 to 1,000 ppm.Additional amounts of less than 0.010 ppm may cause errors. The effect of addition can only be expected within this range, and addition of more than 2ρ00 ppm is not preferable because it is economically disadvantageous compared to the effect obtained by adding it.

There is no particular restriction on the method of adding the ethylene copolymer used in the present invention to a large proportion of medium and/or heavy oil fractions, and the ethylene copolymer can be directly added at room temperature or heated. , usually dissolved in a suitable solvent to give a
Hydrogen dissolved in % by weight, aromatic hydrocarbons, etc. can be used, such as oil repellent, light oil, aromatic pento naphtha, light cycle oil/L/(a fraction produced by petroleum cracking and reforming equipment), etc. , high boiling point solvents with a high content of aromatic hydrocarbons, etc. - The method according to the present invention has an excellent effect of lowering the low-temperature port overclogging temperature of fuel oil compared to the conventional method using a fluidity improver, etc. It is suitable as a method for improving the low-temperature fluidity of contained fuel oils or fuel oils with narrow boiling point ranges.

In the method according to the present invention, rust inhibitors, antioxidants, antistatic agents, anticorrosion agents, etc. that are commonly added to petroleum distillate fuel oils may be used.

In addition, for the purpose of further improving low-temperature fluidity, other fluidity improvers such as chlorinated polyethylene, branched polyethylene, amides or amine salts of akenylsuccinic acid, Friedel-Crafts type hydrocarbon wax naphthalate, long chain It may be used in combination with esters of carboxylic acids and hydroxyl group-containing nitrogen-containing compounds, polyalkyl methacrylates, and the like.

〔Example〕

The present invention will be specifically explained below using Reference Examples, Examples, and Comparative Examples, but the present invention is not limited thereto.

(1) Production of ethylene copolymers Using a high-pressure continuous reactor, various ethylene copolymers were mixed with ethylene and the comonomers shown in Table 1.

Produced under pressure, temperature, 1 polymerization initiator, 1 molecular weight regulator. The properties of the obtained ethylene copolymer are shown in Table 2.〇(2) Preparation and evaluation of fuel oil The L7 fuel oil shown in Table 8 (A), (→ 20%) were added with 200 ppm of each of the various ethylene copolymers A to L produced by the above method and dissolved, and then the low temperature fluidity was measured. Automatic filtration clogging point tester manufactured in accordance with the low temperature filtration clogging t, b point test method shown in the United Kingdom) [manufactured by Yoshida Kagaku Kikai Co., Ltd., A
4F2 type].

The measurement results are shown in Table 4 as an example and in Table 6 as a comparative example. Also, for fuel oil (c) with a relatively narrow boiling point range,
Each of the ethylene copolymers A to L shown in the reference examples was
ppm was added and dissolved, and the low temperature overclogging temperature was measured. The results are shown in Table 6.0 From Tables 4 to 6, the examples according to the present invention are compared with the comparative examples.
It can be seen that the low-temperature port overclogging temperature is low and the low-temperature fluidity is excellent.0 [Effects of the Invention] As explained above, according to the present invention, compared to the conventional method, fuel oil, especially It is possible to provide a low-temperature fluidity improvement method that is highly effective even for fuel oils that contain a relatively large amount of υ-buffin content or for fuel oils that have a narrow boiling point range. For example, it is possible to provide a fluidity improver that is effective even when added in small amounts.

Chapter 4/Table Table 6

Claims (3)

[Claims] (1) Ethylenically unsaturated ester monomer content in fuel oil consisting of a large proportion of medium and/or heavy fractions of petroleum
Low-temperature flow of fuel oil characterized by adding 10 to 2,000 ppm of an ethylene-ethylenic unsaturated ester copolymer having ~50% by weight, a number average molecular weight of 800 to 2,900, and a molecular weight distribution of 4.0 or less. Sex improvement method. (2) A patent claim characterized in that the degree of branching of the ethylene-ethylenically unsaturated ester copolymer has 6 or less methyl-terminated side chains per 100 main chain methylene groups in addition to the methyl groups of the ester groups. The improvement method described in Scope 1. (3) The improved method according to claim 2, wherein the ethylenically unsaturated ester is vinyl acetate.