JP5149564B2 - Emulsion fuel - Google Patents

Description

  The present invention relates to an emulsion fuel.

Emulsion fuel obtained by dispersing water into fuel oil reducing effect has been demonstrated improved and NO _x in the combustion efficiency, as an effective means in terms of reducing environmental load, considering practical application is popularly Yes. As a technique for stably dispersing water in heavy oil, it is known to use a surfactant in combination with a water-soluble polymer such as polyvinylpyrrolidone or polyvinyl alcohol (see, for example, Patent Documents 1 to 6). In addition, a heavy oil emulsion fuel to which a polymer obtained by crosslinking a polymerizable aromatic sulfonate or a copolymer obtained by copolymerizing (meth) acrylic acid and (anhydrous) maleic acid has been proposed ( For example, see Patent Documents 7 and 8.)

JP-A-3-97788 JP-A-6-57268 JP-A-6-88082 JP-A-6-108071 JP-A-6-322382 Japanese Patent Application Laid-Open No. 7-233381 JP-A-8-3573 JP-A-8-73873

However, the conventional emulsion fuel has a problem that the stability is not yet sufficient, and separation is likely to occur over time.
Accordingly, an object of the present invention is to provide an emulsion fuel that is superior in stability over time as compared with conventional emulsion fuels.

Therefore, as a result of intensive studies to solve the above problems, the present inventors have obtained a water-soluble property obtained by radical polymerization of an unsaturated monomer composition containing only a specific hydroxyl group-containing ethylenically unsaturated monomer. The inventors have found that it is effective to use a resin as an emulsifier for an emulsion fuel, and have reached the present invention.
That is, the present invention radically converts an unsaturated monomer composition containing only a hydroxyl group-containing ethylenically unsaturated monomer selected from the group consisting of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate and hydroxybutyl acrylate. An emulsion fuel comprising a water-soluble resin, a fuel oil and water obtained by polymerization , wherein the fuel oil is a light oil, A heavy oil, B heavy oil or C heavy oil.
Moreover, in this invention, it is preferable that content of the water-soluble resin with respect to emulsion fuel is 0.01-5.0 mass%.

  According to the present invention, an emulsion fuel having excellent temporal stability can be provided.

Hereinafter, the present invention will be described in detail.
The emulsion fuel according to the present invention uses a water-soluble resin obtained by radical polymerization of an unsaturated monomer composition containing at least 80% by mass of a hydroxyl group-containing ethylenically unsaturated monomer in fuel oil and water. It is characterized by being added as an emulsifier. When the content of the hydroxyl group-containing ethylenically unsaturated monomer in the unsaturated monomer composition is less than 80% by mass, the solubility of the resulting resin in water is significantly reduced, so that the resin is used as an emulsifier for emulsion fuel. Cannot be used. In addition, the weight average molecular weight of the water-soluble resin in the present invention is preferably 5,000 to 1,000,000 from the viewpoint of further improving the aging stability of the emulsion fuel and the workability during the production of the emulsion fuel.

  The emulsion fuel of the present invention preferably contains 0.01 to 5.0% by mass of a water-soluble resin in terms of active ingredient (as a non-volatile content) with respect to the emulsion fuel. If the content of the water-soluble resin is less than 0.01% by mass, sufficient stability over time may not be obtained, and if it is more than 5.0% by mass, it is economically difficult. The more preferable content of the water-soluble resin is 0.1 to 1.0% by mass.

  Examples of the hydroxyl group-containing ethylenically unsaturated monomer used in the present invention include hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, diethylene glycol mono ( Polytetramethylene glycol mono (meth) such as polyethylene glycol mono (meth) acrylate such as meth) acrylate, polypropylene glycol mono (meth) acrylate such as dipropylene glycol mono (meth) acrylate, ditetramethylene glycol mono (meth) acrylate Polyethylene glycol polypropylene glycol mono (meth) acrylate such as acrylate, diethylene glycol dipropylene glycol mono (meth) acrylate, di Polyethylene glycol polytetramethylene glycol mono (meth) acrylate such as tylene glycol ditetramethylene glycol mono (meth) acrylate, and polypropylene glycol polytetraethylene glycol mono (meth) acrylate such as dipropylene glycol ditetraethylene glycol mono (meth) acrylate , Glycerin mono (meth) acrylate, N-methylol (meth) acrylamide, and allyl alcohol. These hydroxyl group-containing ethylenically unsaturated monomers may be used alone or in combination of two or more. Among these, it is preferable to use one selected from the group consisting of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, and hydroxybutyl acrylate because radical polymerization is easy and water solubility is high.

  The unsaturated monomer composition contains a hydroxyl group-containing ethylenically unsaturated monomer as an essential component, but may contain other unsaturated monomers as long as the effects of the present invention are not impaired. Such an unsaturated monomer has at least one polymerizable vinyl group and does not have a hydroxyl group, and has, for example, a linear, branched or cyclic alkyl chain ( (Meth) acrylic acid esters (methyl (meth) acrylate, ethyl (meth) acrylate, etc.), aromatic vinyl compounds (styrene, α-methylstyrene, etc.), heterocyclic vinyl compounds (vinyl pyrrolidone, etc.), alkylamino (meta) ) Acrylate, vinyl esters (vinyl acetate, vinyl alkanoate, etc.), α, β-unsaturated mono- or dicarboxylic acid (acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, etc.), carboxyl group-containing Vinyl compounds, vinyl cyanide compounds (acrylonitrile, etc.), carbonyl group-containing ethylenically unsaturated monomers (a Lorain, vinyl methyl ketone, etc.), sulfonic acid group-containing ethylenically unsaturated monomers (p-toluenesulfonic acid, etc.), epoxy group-containing α, β-ethylenically unsaturated monomers (glycidyl methacrylate, etc.), water Examples include decomposable alkoxysilyl group-containing α, β-ethylenically unsaturated monomers (γ-methacryloxypropyltrimethoxysilane and the like) and polyfunctional vinyl compounds (divinylbenzene, diallyl phthalate and the like). When such an unsaturated monomer is used, it is appropriately blended within a range not exceeding 20% by mass of the unsaturated monomer composition.

The water-soluble resin in the present invention is produced by radical polymerization. Although the temperature at the time of radical polymerization reaction is not specifically limited, It is preferable that it is 40-130 degreeC.
The unsaturated monomer composition can contain a solvent, a polymerization initiator, and the like. Examples of the solvent include water alone, a water-soluble solvent or a mixture of a hydrophilic solvent and water, or a water-soluble solvent or a hydrophilic solvent alone. Examples of the water-soluble solvent and the hydrophilic solvent include methyl alcohol, ethyl alcohol, n-butyl alcohol, isobutyl alcohol, n-propyl alcohol, isopropyl alcohol, amyl alcohol, isoamyl alcohol, ethylene glycol, ethylene glycol monomethyl ether, and ethylene glycol. Monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monoisopropyl ether, propylene glycol mono Butyl ether, dipro Glycol monobutyl ether, tripropylene glycol monobutyl ether. These can be used alone or in combination of two or more. The amount of the solvent used is not particularly limited, but is preferably 10% by mass to 80% by mass from the viewpoint of workability at the time of preparing the emulsion fuel.

  Examples of the polymerization initiator include known water-soluble polymerization initiators and oil-soluble polymerization initiators used for radical polymerization. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, water-soluble azo compounds such as 2,2′-azobis (2-methylpropionamidine) dihydrochloride hydrochloride, and t-butyl. Examples thereof include organic peroxides such as hydroperoxide and cumene hydroperoxide, and hydrogen peroxide. Examples of the oil-soluble polymerization initiator include azo initiators such as 2,2-azobis-isobutyronitrile, and organic peroxides such as benzoyl peroxide, acetyl peroxide, and lauroyl peroxide. These may be used individually by 1 type and may be used in combination of 2 or more type.

  Moreover, a reducing agent can be used as needed. Examples of the reducing agent include reducing organic compounds such as ascorbic acid, tartaric acid, citric acid, and formaldehyde sulfoxylate metal salts, and reducing inorganic compounds such as sodium thiosulfate, sodium sulfite, and sodium bisulfite. When adjusting the weight average molecular weight of the water-soluble resin to be obtained, a chain transfer agent may be used as necessary. Examples of the chain transfer agent include n-dodecyl mercaptan, tert-dodecyl mercaptan, n-butyl mercaptan, 2-ethylhexyl thioglycolate, β-mercaptopropionic acid, methyl alcohol and isopropyl alcohol.

As fuel oil in this invention, all the fuel oils which can be used with internal combustion engines, such as a petroleum fraction and a vegetable oil, can be used. Preferred are light oil, heavy fuel oil A, heavy fuel oil B, heavy fuel oil C, and more preferred is heavy fuel oil C.
Moreover, the content of water with respect to the emulsion fuel of the present invention is preferably 1 to 50% by mass, and more preferably 10 to 30% by mass.

  The emulsion fuel of the present invention is produced by emulsifying the above-described water-soluble resin, fuel oil, and water using a known emulsification means. Examples of emulsifying means include emulsifiers and dispersers such as homomixers, line mixers, and ultrasonic emulsifiers. The particle diameter of the emulsion is preferably 1 to 5 μm from the viewpoint of obtaining an emulsion fuel with more excellent stability over time.

  The emulsion fuel of the present invention can be obtained with sufficient stability over time only by using the above-mentioned water-soluble resin as an emulsifier. However, known nonionic surfactants, anionic surfactants, cationic surfactants, An amphoteric surfactant or the like may be used in combination as necessary.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to these. The measurement of various physical properties and the preparation of emulsion fuel in Synthesis Examples, Examples and Comparative Examples were carried out by the following methods.

(Measurement of weight average molecular weight ( _Mw ) of resin)
Using the following apparatus, the weight average molecular weight of the resin was measured using a 0.1 M sodium nitrate aqueous solution as a carrier at a sample concentration of about 0.1 mass% and a flow rate of 1 mL / min during measurement.
Equipment used: Gel permeation chromatography column; OHPAK SB-806M HQ manufactured by Showa Denko KK
Standard sample: Pullulan (P-82, Showa Denko KK)

(Method for preparing emulsion fuel)
A resin or surfactant was added to the water and stirred before mixing with fuel oil. In a state separated into two phases, T.K. Using K-Robomix, the mixture was stirred for 5 minutes at a rotation speed of a stirring blade of 4,000 rpm to prepare an emulsion fuel.

(Viscosity of emulsion fuel)
Using a Brookfield rotational viscometer, the measurement was performed at a liquid temperature of 23 ° C. and a rotation speed of 60 rpm.

(Measurement of particle size in emulsion fuel)
The size of the particles was directly observed with a microscope.

(Evaluation of stability of emulsion fuel over time)
The emulsion fuel produced by the above method was sealed in a glass bottle and allowed to stand at 23 ° C. and 50 ° C. for 7 days, and the viscosity change and particle size change of the emulsion fuel were measured. A sample in which the viscosity and particle size hardly change immediately after preparation and after standing for 7 days was marked with ◯, and other samples were marked with ×.

<Synthesis Example 1>
A four-necked flask reactor equipped with a stirrer, a thermometer, and a reflux condenser was charged with 93 parts by mass of ion-exchanged water as a solvent and 6.5 parts by mass of isopropyl alcohol, and the temperature was raised to 80 ° C. 0.5 parts by mass of potassium persulfate as a polymerization initiator was added, and 100 parts by mass of hydroxyethyl acrylate (HEA) was added dropwise over 2 hours. During the dropping, the temperature in the reactor was kept at about 80 ° C. After completion of dropping, the mixture was kept at about 80 ° C. for 1 hour and cooled, and then the resin solution was taken out from the reactor (hereinafter referred to as “resin solution A”). The obtained resin solution A had a nonvolatile content of 50 mass% and a weight average molecular weight (M _w ) of 215,000.

<Synthesis Example 2>
A four-necked flask reactor equipped with a stirrer, a thermometer, and a reflux condenser was charged with 84 parts by mass of ion-exchanged water and 15.5 parts by mass of isopropyl alcohol, and the temperature was raised to 80 ° C. 0.5 parts by mass of potassium persulfate was added, and 100 parts by mass of hydroxyethyl acrylate (HEA) was added dropwise over 2 hours. During the dropping, the temperature in the reactor was kept at about 80 ° C. After completion of dropping, the mixture was kept at about 80 ° C. for 1 hour and cooled, and then the resin solution was taken out of the reactor (hereinafter referred to as “resin solution B”). The obtained resin solution B had a nonvolatile content of 50 mass% and a weight average molecular weight (M _w ) of 56,200.

<Synthesis Example 3>
A four-necked flask reactor equipped with a stirrer, a thermometer and a reflux condenser was charged with 93 parts by mass of ion-exchanged water and 6.5 parts by mass of isopropyl alcohol, and the temperature was raised to 80 ° C. 0.5 parts by mass of potassium persulfate was added, and 80 parts by mass of hydroxyethyl acrylate (HEA) and 20 parts by mass of hydroxyethyl methacrylate (HEMA) were added dropwise over 2 hours. During the dropping, the temperature in the reactor was kept at about 80 ° C. After completion of dropping, the mixture was kept at about 80 ° C. for 1 hour and cooled, and then the resin solution was taken out from the reactor (hereinafter referred to as “resin solution C”). The obtained resin solution C had a nonvolatile content of 50 mass% and a weight average molecular weight (M _w ) of 300,200.

<Reference Synthesis Example 1>
A four-necked flask reactor equipped with a stirrer, a thermometer, and a reflux condenser was charged with 84 parts by mass of ion-exchanged water and 15.5 parts by mass of isopropyl alcohol, and the temperature was raised to 80 ° C. When 0.5 parts by mass of potassium persulfate was added and 75 parts by mass of hydroxyethyl acrylate (HEA) and 25 parts by mass of methyl methacrylate (MMA) were added dropwise over 2 hours, the resin was insolubilized and precipitated, and the resin solution Was not obtained. During the dropping, the temperature in the reactor was kept at about 80 ° C.

<Example 1>
2 parts by mass of resin solution A (1 part by mass as a nonvolatile content) was added to 79 parts by mass of water and stirred, and then mixed with 320 parts by mass of commercially available heavy fuel oil C to prepare an emulsion fuel according to the above method. The viscosity immediately after preparation was 460 mPa · s, and the particle size was 1 to 3 μm. The viscosities after standing at 23 ° C. and 50 ° C. for 7 days were 500 mPa · s and 480 mPa · s, respectively, and the particle diameter hardly changed.

<Example 2>
2 parts by mass of resin solution B (1 part by mass as a nonvolatile content) was added to 79 parts by mass of water and stirred, and then mixed with 320 parts by mass of commercially available C heavy oil to prepare an emulsion fuel according to the above method. The viscosity immediately after preparation was 430 mPa · s, and the particle size was 1 to 3 μm. The viscosities after standing at 23 ° C. and 50 ° C. for 7 days were 500 mPa · s and 480 mPa · s, respectively, and the particle diameter hardly changed.

<Example 3>
After 2 parts by mass of resin solution C (1 part by mass as a non-volatile content) was added to 79 parts by mass of water and stirred, this was mixed with 320 parts by mass of commercially available C heavy oil, and an emulsion fuel was prepared according to the above method. The viscosity immediately after preparation was 480 mPa · s, and the particle size was 1 to 3 μm. The viscosities after standing at 23 ° C. and 50 ° C. for 7 days were 490 mPa · s and 470 mPa · s, respectively, and the particle diameter hardly changed.

<Comparative Example 1>
80 parts by mass of water and 320 parts by mass of commercially available C heavy oil were mixed, and an emulsion fuel was prepared according to the above method. The viscosity immediately after the preparation was 510 mPa · s, and the particle diameter was 1 to 7 μm. The viscosities after standing for 7 days at 23 ° C. and 50 ° C. were 740 mPa · s and 350 mPa · s, respectively. The particle diameter after standing at 23 ° C. for 7 days was 1 to 10 μm. The particle size after standing at 50 ° C. for 7 days was about 20 μm (however, there were almost no particles).

<Comparative example 2>
After adding 1.0 part by mass of oil-soluble nonionic surfactant (polyoxyethylene nonylphenyl ether, HLB7.8) to 320 parts by mass of commercially available C heavy oil, this is mixed with 80 parts by mass of water, and the above method An emulsion fuel was prepared according to The viscosity immediately after production was 550 mPa · s, and the particle diameter was 1 to 6 μm. The viscosities after standing at 23 ° C. and 50 ° C. for 7 days were 680 mPa · s and 360 mPa · s, respectively. The particle size after standing at 23 ° C. for 7 days hardly changed, but the particle size after standing at 50 ° C. for 7 days was 1 to 15 μm.

<Comparative Example 3>
Hydrophilic nonionic surfactant (polyoxyethylene alkyl ether, HLB13.5) 1.0 part by mass and 20% polyvinyl alcohol aqueous solution (PVA205 manufactured by Kuraray Co., Ltd.) 0.5 part by mass (0.1 parts by mass as non-volatile content) ) Was added to 79 parts by weight of water and stirred, and then mixed with 320 parts by weight of commercially available C heavy oil to prepare an emulsion fuel according to the above method. The viscosity immediately after preparation was 600 mPa · s, and the particle size was 1 to 6 μm. The viscosities after standing for 7 days at 23 ° C. and 50 ° C. were 690 mPa · s and 610 mPa · s, respectively. The particle size after standing at 23 ° C. for 7 days hardly changed, but the particle size after standing at 50 ° C. for 7 days was 1 to 10 μm.

  From Tables 2 and 3, it is obvious that the emulsion fuels of Examples 1 to 3 are superior in stability over time to Comparative Example 1 in which no emulsifier is added, and Comparative Examples 2 and 3 corresponding to conventional emulsion fuels and Even if it compares, it turns out that it is excellent in stability with time.

Claims (2)

Water solution obtained by radical polymerization of an unsaturated monomer composition containing only a hydroxyl group-containing ethylenically unsaturated monomer selected from the group consisting of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate and hydroxybutyl acrylate Containing functional resin, fuel oil and water ,
The emulsion fuel, wherein the fuel oil is light oil, heavy oil A, heavy oil B or heavy oil C.   The emulsion fuel according to claim 1, wherein the content of the water-soluble resin with respect to the emulsion fuel is 0.01 to 5.0 mass%.