JPH0228403A - Prevention of dust generation - Google Patents

Abstract

PURPOSE:To reduce the amount of dust prevention agent used and improve the efficiency thereof by spraying a water solution of a high polymer of a specified mean molecular weight and having a carboxyl radical or acid anhydride and a water solution of an alkali to a dust generating substance such as coal. CONSTITUTION:A water solution is prepared which contains a copolymer of a single polymer of a compound with three or more carbon atoms having a carboxyl radical or an acid anhydride and polymeric carbon-carbon double bond or a vinyl compound capable of making a copolymer with them, and further contains high polymer compound of a partial ester compound or partial amide compound of mean molecular weight of 1000-1,000,000. A water solution of alkali such as sodium hydroxide is prepared. Both of these solutions are sprayed to a dust generating substance. With this constitution dust is effectively prevented from being generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a dust generation prevention method for preventing dust generation from dust generating substances such as coal and oil coke.

[Conventional technology]

BACKGROUND OF THE INVENTION Currently, solid raw materials used in various industrial fields take various forms due to handling and transportation problems, but in most cases they are powders and have dust-generating properties. These dust-producing substances generate dust during transportation and storage, polluting the environment.

This has become a major problem as it reduces labor efficiency, increases transportation losses, and even causes dust explosions.

As a means to prevent this, in the case of coal, etc., a method is used to spray an aqueous solution or aqueous dispersion containing a substance that prevents dust generation. For example, methods of spraying an aqueous solution containing a surfactant and a water retention agent are known, as disclosed in Japanese Patent Application Laid-open No. 5667385 and Japanese Patent Publication No. 57-14719.

In addition, in order to prevent dust generation even after moisture evaporates,
In addition to cement bases as shown in JP-A-40595, asphalt emulsions as shown in JP-A-50-40491, as well as JP-A-59-. 51993, JP 59-25871, JP 48-713
Publication No. 83, Special Publication No. 51-7637, Special Publication No. 1983
Various methods have also been attempted in which an aqueous solution or dispersion of a polymer compound is sprayed, as shown in Japanese Patent Application Laid-open No. 38082 and Japanese Patent Application Laid-Open No. 133392/1982.

[Problem to be solved by the invention]

However, in these conventionally known methods, unless the dust generation prevention substance is used in a considerably large amount relative to the dust generation substance,
It is economically disadvantageous because it does not have sufficient effect,
Furthermore, those containing cement base or metal salts have the problem of lowering the commercial value of the dust-generating substance.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, it is an object of the present invention to provide a dust generation prevention method that can effectively prevent dust generation by using a relatively small amount of dust generation prevention substance.

[Means to solve the problem]

As a result of intensive studies to achieve the above object, the present inventors sprayed an aqueous solution containing a specific polymer compound and an aqueous solution of an alkaline substance on dust-producing substances, and By reacting on the surface of the substance to thicken and gel, it is possible to effectively prevent dust generation using a relatively small amount of the above-mentioned polymer compound and alkaline substance, and the above-mentioned effect is maintained even after the spray liquid dries. This led to the completion of the present invention.

That is, the present invention provides dust-producing substances with A) an average molecule of 11.0 having a carboxyl group or an acid anhydride group in the molecule;
The present invention relates to a dust generation prevention method characterized by spraying an aqueous solution or aqueous dispersion of a polymer compound having a molecular weight of 1,000 to 1,000,000 and B) an aqueous solution of an alkaline substance.

[Structure and operation of the invention]

The polymer compound having a carboxyl group or an acid anhydride group in the molecule in component A of the present invention includes a carbon number of 3 or more and having a carboxyl group or an acid anhydride group and a polymerizable carbon-carbon double bond in the molecule. A homopolymer of a compound (hereinafter referred to as an acid group-containing compound), or a copolymer with a vinyl compound that can be copolymerized with the same, and a partial esterification product or copolymer of these homopolymers or copolymers. Partially amidated products can be mentioned. Among these, the above-mentioned partially esterified products or partially amidated products whose esterification rate or amidation rate is 95 mol % or less are particularly preferred.

The average molecular weight of these polymer compounds is 1,000 to 10
00,000, preferably in the range of 2,000 to 800,000. If the molecular weight is less than 1,000,000, the solubility in water will be strong (and if it exceeds 1,000,000, the handleability will be poor in terms of viscosity etc. when dissolved and dispersed in water. In either case, it is difficult to obtain favorable results.

Examples of the acid group-containing compounds mentioned above include acrylic acid, methacrylic acid, maleic anhydride, itaconic acid, and fumaric acid, and examples of vinyl compounds that can be copolymerized with these include α-olefins such as ethylene and isobutylene. ,
Examples include styrene, vinyl acetate, allyl alcohol, acrylamide, acrylic acid alkyl ester, methacrylic acid alkyl ester, and the like. Here, the amount of the latter vinyl compound to be used is such that its proportion in the total amount with the acid group-containing compound is usually 95 mol% or less, preferably 80 mol% or less.

Typical examples of polymer compounds using these compounds include polyacrylic acid, polymethacrylic acid, and acrylic acid.
Maleic anhydride copolymer, methacrylic acid-maleic anhydride copolymer, ethylene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, vinyl acetate-maleic anhydride Acid copolymer, allyl alcohol-maleic anhydride copolymer, vinyl acetate-acrylic acid copolymer, vinyl acetate-methacrylic acid copolymer, allyl alcohol-acrylic acid copolymer, allyl alcohol-methacrylic acid copolymer Examples include polymers and partially esterified or partially amidated products thereof.

In addition, the alcohol used to make the partially esterified product includes methanol, ethanol, propatool, butanol, hexanol, octatool, 2-ethylhexanol, nonanol, dodecanol, tridecanol,
1 to 30 carbon atoms such as tetradecanol, pencudecanol, hexadecanol, octadecanol, oleyl alcohol, benzyl alcohol, cyclohexanol, etc.
fatty acid alcohols, aromatic alcohols, alicyclic alcohols and their alkylene oxide adducts,
Polyhydric alcohols such as ethylene glycol, propylene glycol, trimethylolpropane, pentaerythritol, sorbitol, sorbitan, sugar, etc., and their partially esterified products, polyoxyalkylene adducts, and polyoxyalkylene alkylphenols with reactive hydroxyl groups There are compounds.

In addition, amino compounds used to form partially amidated products include ammonia, methylamine, ethylamine,
In addition to monoamines such as propylamine, butylamine, octylamine, and dodecylamine, there are polyvalent amines such as ethylenediamine and diethylenetriamine, and alkylolamines such as monoethanolamine and jetanolamine.

Component A used in the present invention is an aqueous solution or aqueous dispersion of the above-mentioned polymer compound, and can be obtained by any method depending on the type of polymer compound. For example, a monomer consisting of an acid group-containing compound or a vinyl compound copolymerizable with the same is polymerized in water, an organic solvent, or a mixed solvent of water and an organic solvent using an appropriate polymerization initiator. When this polymerization is carried out in water, if the homopolymer or copolymer as a reaction product is water-soluble, it can be made into an aqueous solution as it is, or if it is poorly water-soluble or water-insoluble, it can be treated with a dispersant such as a surfactant. It can be obtained as an aqueous dispersion.

On the other hand, if the above polymerization was carried out in an organic solvent or a mixed solvent of water and organic solvent, the solvent is removed after the reaction, and if the resulting homopolymer or copolymer is solid, it is pulverized. After making it into a fine powder, it may be dissolved in water to make an aqueous solution, or it may be made into an aqueous dispersion using a dispersant such as a surfactant. Note that if a satisfactory aqueous solution or aqueous dispersion state cannot be obtained even after performing this operation, partial neutralization may be performed by adding an alkaline substance to an extent that gelation does not occur.

In addition, when the polymer compound is a partially esterified product or a partially amidated product, after obtaining a homopolymer or copolymer having a carboxyl group or an acid anhydride group in the molecule as described above, the partially esterified product is obtained. Alternatively, an esterified product or an amidated product of the acid group-containing compound may be used as at least one of the monomers to form a single aqueous solution or aqueous dispersion. It may be polymerized or copolymerized and then partially hydrolyzed in water to form an aqueous solution or dispersion.

Component B used in the present invention is an aqueous solution of various alkaline substances, and can be arbitrarily used from strongly alkaline substances to slightly alkaline substances. For example, potassium hydroxide, sodium hydroxide, water-soluble lower amines such as ammonia and methylamine, alkylolamines such as monoethanolamine, weak acid salts of strong alkaline substances such as formates and acetates of sodium hydroxide and ammonia,
Propionate, carbonate, hydrogen carbonate, etc. are used.

These alkaline substances can be selected depending on the type of dust-generating substance. For example, if the dust-generating substance is a fuel such as coal or oil coke, metals such as potassium or sodium can be selected. This is not preferred because it may increase corrosion of the boiler, and ammonia, lower amines, alkylolamines, and weak acid salts thereof are usually used as suitable ones.

Note that among the alkaline substances, it is particularly preferable to use carbonate or hydrogen carbonate because the following advantages can be obtained. That is, these salts react with component A to generate carbon dioxide gas, so that after the components A and B come into contact, they foam and gel.
As a result, the coating efficiency against dust-producing substances increases, and a strong foamed film is formed after drying.

In addition, since oxygen on the surface of dust-producing substances is replaced by inert carbon dioxide gas, when the method of the present invention is applied to the surface of a coal storage pile where a large amount of coal is piled up, the movement of oxygen into the coal storage pile is effective. This has the advantage of preventing spontaneous combustion during coal storage, which is currently a major problem.

In the present invention, component A consisting of an aqueous solution or aqueous dispersion of a polymer compound as described above and component B consisting of an aqueous solution of an alkaline substance are sprayed onto a dust-generating substance, and both of the above components are applied to the surface of the substance. By reacting to thicken and form a gel, the adhesive force can be used to adhere dust-producing substances, especially minute powder particles, and prevent dust generation caused by minute particles. This makes it possible to effectively prevent dust generation even if the amount of the dust generation prevention substance made of the above-mentioned polymer compound and alkaline substance is used, and the advantages include the ease of handling the spray liquid and the ease of spraying on dust-generating substances. As a result, the economic effect can be greatly increased.

That is, the polymer compound having a carboxyl group or an acid anhydride group in the molecule in the component A of the present invention is considered to have a so-called thread-like state in which the molecules are entangled in water. It is very easy to handle whether it is made into an aqueous solution or an aqueous dispersion.

When the alkaline substance of component B is brought into contact with this state, the carboxyl groups and acid anhydride groups are neutralized, and due to the repulsion of the cationic groups of the alkaline substance, the molecules become elongated, lose fluidity, and become extremely viscous. It changes to a gel state.

If such a polymer substance, which has been neutralized from the beginning, is used as a spray liquid, it will take a long time to dissolve in water. It is necessary to provide a dedicated dissolution tank with
Even when it is made into an aqueous solution or aqueous dispersion during production, only a very low concentration can be produced, and considering the transportation cost to bring it to the coal storage site and other sites mentioned above, industrialization is completely impossible from an economic standpoint. You can say that.

On the other hand, in the method of the present invention described above, component A can be handled as a fluid consisting of an aqueous solution or an aqueous dispersion at a high concentration. It can be diluted and sprayed, and even if the concentration of the spray liquid is low, it can thicken and gel as described above upon contact with an alkaline substance, and exhibits a good dustproofing function. In other words, transportation and spraying operations can be carried out economically and easily, and the dust-proofing effect is also improved.

The dust-generating substance to which the present invention is applied may be any substance, such as coal, oil coke, iron ore, sand, earth, calcium carbonate, titanium oxide, talc, and asbestos. Among these, it has been difficult to prevent oil coke from generating dust using conventional techniques, but according to the present invention, dust generation can be effectively prevented as well as from other types of oil coke. It can be said that the effect of application is particularly large.

In the present invention, the method of spraying component A and component B onto such dust-producing substances is not particularly limited, but
One method is to spray either component A or component B onto a dust-producing substance using a spray gun, mix and allow it to penetrate, and then spray and mix the other component using the same method. . When adopting this method, A
The concentration of the polymer compound in the component and the concentration of the alkaline substance in the component B may both be set within the range of usually 0.01 to 90% by weight, preferably 0.1 to 60% by weight.

Another method is to spray either component A or component B with a spray gun or the like on the dust-generating materials piled up in the open, and then spray the remaining one by the same means. There is a method in which a thickened, gelled film is formed on the pile, and a solidified layer is formed after the water evaporates. When this method is adopted, the concentration of the polymer compound in component A and the concentration of the alkaline substance in component B are usually set to 0.
O may be set in a range of 1 to 90% by weight, preferably 1 to 80% by weight. In addition, when carbonate or hydrogen carbonate is used as component B, as mentioned above, a foamed film is formed based on the generation of carbon dioxide gas, which dramatically improves coating efficiency and suppresses spontaneous combustion. Moreover, advantages such as increased strength of the consolidated layer can be obtained.

In these spraying operations, the amount of spraying of component A and component B is such that the solid content of both components, that is, the total amount of polymeric substances and alkaline substances, is 5 ppm to 5% by weight, preferably 10 ppm to 1 weight%, based on the dust-generating substance. It is preferable to keep the amount within a range of 1.5%; too little will result in little effect, and too much will be economically disadvantageous. In addition, the amount of component B to be used relative to component A is an amount sufficient to neutralize the carboxyl group or acid anhydride group contained in the polymer compound in component A, that is, a neutralization equivalent to or more than the above group. The amount may include an alkaline substance.

In addition, during the above-mentioned spraying, a surfactant such as a nonionic surfactant or anionic surfactant may be added to the A or B component for the purpose of promoting the penetration of the A and B components into the dust-generating substance. A water-soluble polymer such as carboxymethylcellulose alcohol may be added to component A or component B for the purpose of promoting gelation or stabilizing foam when forming a foamed film. It is also possible to further increase the dust prevention effect.

〔Effect of the invention〕

As described above, in the present invention, by adopting a simple method of spraying two liquids consisting of components A and B that separately contain a specific polymer compound and an alkaline substance as a dust prevention substance, Even if the amount of the above-mentioned dust generation prevention substance used is small, a large dust generation prevention effect can be obtained, and it is also possible to achieve special effects that cannot be achieved with conventional technology, such as improved workability. .

〔Example〕

Next, examples of the present invention will be described in more detail. In addition, hereinafter, % and parts mean % and parts by weight unless otherwise specified.

In addition, A-1 to 15 (polymer compounds of component A) and B as dust prevention substances used in the following examples and comparative examples.
-1~8 (Alkaline substance of component B) and C-1~
4 (other substances) is the following 1. These are shown in Table 2.

Table 1 Example 1 Australian Preasol charcoal was air-dried, with a total water content of 1
Raw coal of 0% was prepared. This was placed in a Nigu, water and a diluted solution of the agent (dust generation prevention substance) shown in Table 3.4 were added while spraying, and the mixture was stirred at 60 rpm for a total of 10 minutes.
It was subjected to a st Box test to examine its dust generation prevention effect.

In the case of the example of the present invention, component A is first added so that the chemical concentration is 70 ppm based on the coal, and after 5 minutes, component B is added so that the chemical concentration is 30 ppm based on the coal.
The mixture was stirred for a minute and subjected to the above test.

In addition, in the case of the comparative example, the chemical was lOOpp against coal.
m and stirred for 10 minutes, then subjected to the above test.

In addition, in the above Dust Box test, a certain amount (22
, 7 kg) is dropped from the top of the Box at a height of 152.5 am, and after 120 seconds, a plate is inserted at 61 CIR from the bottom, and the amount of coal deposited on the plate is calculated by the C-D-1 value (
CD-1 values were measured when the total water content was 13%, 15%, and 18% for both the present invention example and the comparative example. The larger this value, the greater the amount of dust generated. The results were as shown in Table 3.4 below.

As is clear from Tables 3 and 4 above, C-
It can be seen that the D-1 value is much smaller than that of the comparative example, and the dust generation prevention effect is greater.

Example 2 700 g of American oil coke with an average particle size of 220 μm and a total moisture content of 2% was placed in a 20 cm diameter petri dish, and in the case of the present invention example shown in Table 5, the drug (polymer compound) concentration was 1%. Spray component A diluted with water so that the ratio is 11 per 1% of the surface area of the oil coke, and after 3 minutes spray component B, which is a 0.5% diluted aqueous solution of a chemical (alkaline substance), onto the oil coke. 1 per 11 surface areas
I sprayed it so that it was 1. In addition, in the case of the comparative example shown in the same table, a diluted solution obtained by diluting the chemical with water to 0.75% was added to the surface area of oil coke. (21 sprays per area.

Each petri dish was left indoors for one week, then the petri dish was
The weight of the scattered dust was measured by blowing a wind of 10 m/sec for 10 minutes using a rotor.The results are shown in Table 5 below.

In each of the above test examples, sodium di-2-ethylhexyl sulfosuccinate was added in an amount of 5% based on the active pharmaceutical ingredient in order to improve the wettability of petroleum coke.

Table 5 As is clear from Table 5 above, in the example of the present invention, a sufficient solidified layer can be formed on the surface of oil coke, which effectively reduces the dust scattering of oil coke. It can be seen that this can be prevented.

Example 3 Using Datong charcoal from China, an open conical pile of approximately 5.0001-ton was made, and in the case of the present invention example shown in Table 6, the drug (polymer compound) concentration was Component A diluted with water to a concentration of 0.5% is sprayed to a concentration of 0.71 per surface area IM of the coal pile, and after the spraying is finished, component B consisting of a 1.5% aqueous solution of a chemical (alkaline substance) is sprayed onto the coal. 0.31 sprays were applied per pile surface area. In addition, in the case of the comparative example shown in the same table, the drug was mixed with water for 1.
The diluent diluted to 5% was sprayed 11 times per surface area IM of the coal pile. Thereafter, a thermometer was inserted into the center of the conical pile, and changes in temperature were measured every month for three months. The results were as shown in Table 6.

Table Note: * indicates a temperature of 200°C or higher, indicating that spontaneous combustion occurred.

As is clear from Table 6 above, in the case of the inventive example, the temperature rise due to automatic oxidation of the coal was effectively prevented, whereas in the comparative example, the temperature rise was significant, leading to spontaneous combustion. Ta.

Claims (1)

[Claims] (1) For the dust-generating substance, A) an aqueous solution or aqueous dispersion of a polymer compound having an average molecular weight of 1,000 to 1,000,000 and having a carboxyl group or an acid anhydride group in the molecule, and B) an aqueous solution of an alkaline substance. A dust generation prevention method characterized by spraying.