JP2593697B2 - Coal handling management method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a method for managing and handling coal, and in particular, to prevent spontaneous combustion due to oxidation of coal, prevent scattering of coal powder,
The present invention relates to a method for managing coal handling such as improving the efficiency of compaction work of coal deposits using machinery such as a bulldozer.

[Prior art]

Conventionally, in coal-fired power plants, steel mills, coke factories, other factories that use or store coal, call centers, etc., thousands to hundreds of thousands of tons of coal are deposited indoors or in the open air, Work such as transporting it to the required location is performed. Here, examples of coal include so-called anthracite, bituminous coal, lignite, lignite, and the like. Coal is oxidized by oxygen when exposed to air (a relatively mild oxidation reaction is sometimes called "weathering" or "decomposition"). When the outside air temperature is high, when the wind is received, or the like, air oxidation as a chemical reaction is promoted. In addition, when the storage is performed for a long time, the oxidation of the coal constituents further proceeds, and when the heat generated thereby accumulates, the coal spontaneously ignites. During strong winds, the powder contained in coal deposits scatters,
Alternatively, there is a problem that the water is washed out by rainwater and harms the surrounding environment. In order to minimize the problems that occur when handling coal in this way, the following methods have been proposed. (1) Sprinkling water on coal deposits. (2) Compact the coal deposit with a truck, bulldozer, etc. and compact it. (3) Cover the coal deposit with a tent or sheet. (4) The coal deposit is covered with a coating such as a polymer resin emulsion or latex or a cement coating. (5) Supply inert gas to coal deposits.

[Problems to be solved by the invention]

However, the method (1) proposed above requires that the coal sediment be continuously drained due to the water escaping due to the drying, and that the scattering of the coal powder is prevented, especially on windy winds. Therefore, it is necessary to use a large amount of water. Further, in order to cope with the change of the wind and the direction of the wind, the sprinkling equipment becomes complicated and various adjustments are required for the sprinkling method. As a result, there arises a problem that the amount of water adhering to the coal becomes excessively high. In addition, it is inevitable that excess removal water will flow out of the coal sediment with coal powder or soluble components, and extra facilities, labor and cost will be required to treat this blackish brown effluent. become. Next, in the above method (2), every time the deposited layer is piled up to a height (thickness) of, for example, 0.5 meter to 1 meter over the entire surface of the coal deposit, the compactor is compacted with a truck or a bulldozer and compacted. However, it is not easy to squeeze until sufficient airtightness is maintained. In order to ensure long-term coal storage preservation, it is necessary to provide sufficient compaction-filling properties and increase the barrier properties so that the outside air does not immerse in the coal deposits. It requires a lot of work time and a lot of labor and cost. In this case, the rolling pressure on the inclined side portion is more difficult than on the upper surface, and the air blocking performance is low. Therefore, when this slope part receives the blowing of the wind,
Air oxidation progresses more and spontaneous ignition is more likely to occur. If the temperature inside the coal pile rises to about 60-80 ° C and the danger of spontaneous ignition is predicted, transshipment is necessary to measure the heat release and prevent spontaneous ignition. This transshipment is a laborious and difficult task because it is a double operation of breaking down the rolled-up sediment, carrying it out, and spreading it out or reloading it again. As described above, the rolling method using a machine such as a truck, a roller, and a bulldozer is not always a sufficient measure. In addition, the above measure (3) requires additional measures in the event of a gust, in terms of the material cost of the awning or sheet and the labor required for coating, and the cost is enormous.
In this method, although the scattering of coal powder can be prevented and the blowing of wind can be prevented, the effect of restricting the contact between coal and air is small. From this viewpoint, this method is a simple method when the amount of coal is relatively small, but cannot be said to be an economical and rational measure when storing a large amount of coal. The method of the above (4) is to apply a vinyl acetate-based
This is a method of forming a solid film such as an acrylic / synthetic rubber-based latex / emulsion or a polyolefin-based resin, which is effective in preventing runoff or scattering by rainwater or wind, but requires a large material cost. And since the formed film is a thin plastic solid film,
Deformation or cracking of the coating is likely to occur due to deformation of the coal seam, changes in temperature, or wind and rain, and as a result, there is a drawback that air and rainwater enter therefrom and impair the ability to block outside air. In addition, when using inorganic materials such as cement,
This cement content impairs the quality of the coal and adversely affects the use of the coal in a later step, so that it is difficult to adopt it for general purposes. In the method (5), it is necessary to prevent leakage of the supplied inert gas or gas in an atmosphere in which the inert gas is mixed. Especially when a large amount of coal is stored or transported, and when it is used for a long period of time, it is necessary to continuously supply the required amount of inert gas together with measures to prevent this leakage. Practical application is difficult.

[Means for solving the problems]

The present inventors have conducted intensive studies to solve the above problems, and as a result, have developed a coal handling management method that solves the above problems at once. That is, the present invention relates to a method for controlling the handling of coal by attaching a coating agent to a large number of coals, wherein an emulsion of a water-in-oil type water-swellable polymer or an aqueous dispersion thereof is used as the coating agent. It is a coal management method characterized by the following. By the action of the coating treatment agent of the present invention, (1) suppressing oxidation of coal to prevent spontaneous ignition, (2) suppressing scattering of coal powder, and (3) compaction using trucks, bulldozers and the like. For example, it is possible to safely and smoothly perform the coal management and management, that is, the accumulation and transportation of the coal, such as improving the effect.

[Action]

The water-in-oil type water-swellable polymer emulsion or its water dispersion used as the coating agent of the present invention has a structural viscosity of thixotropic. Therefore, it shows characteristics that it is easy to flow and hard to be lost, and has good coating and filling properties for coal. Thus, contact between the coal and the outside air is prevented, and air is prevented from penetrating or passing through the gaps between the coal lump particles. This effect, which should be referred to as "air blocking action", suppresses or prevents a chemical reaction that occurs when the coal comes into contact with oxygen in the air, that is, oxidation, weathering, heat generation, spontaneous ignition, and the like. Furthermore, since this coating treatment agent is in a state similar to a sticky gel-like material, it becomes a film having water retention,
Prevents scattering of coal powder by wind. This coating treatment agent, which is present inside and outside of coal or coal deposits, has a large ability to prevent the scattering of coal powder and is excellent in avoiding environmental pollution, as compared with a mere water spray film. The coating agent of the present invention reduces the frictional resistance between coal lump particles and provides lubricity by a kind of bearing effect by the spherical particles in the polymer emulsion. Therefore, the rolling operation using a truck, a bulldozer or the like becomes easier, and the working efficiency is improved. When the present coating treatment agent is used, the degree of compaction work can be reduced as compared with the case where it is not used or the case where only water is used. By performing the compaction work using the present coating treatment agent, the improvement of the compaction work efficiency is added to the "air blocking effect" of the coating treatment agent, and as a result, the oxidation of coal is more completely prevented. You. The effect of improving the efficiency of the compaction operation is that the particles in the emulsion of the water-in-oil type water-swellable polymer contained in the coating agent of the present invention cause a water absorption reaction when they encounter water molecules, It swells to a volume of more than 100 times to form aggregates of minute spherical hydrogels, which exert a kind of bearing effect, reduce frictional resistance between coal lump particles, and lubricate It is thought to give sex. (Specific Configuration) In the present invention, an emulsion of a water-in-oil type water-swellable polymer or an aqueous dispersion thereof is used as a film-treating agent.
An emulsion of a water-in-oil type water-swellable polymer proposed in JP-A-63-90510 and JP-A-63-90537 or an aqueous dispersion thereof is used. Emulsions of the water-in-oil swellable polymer include a water-soluble anionic vinyl monomer, a cationic vinyl monomer, or a nonionic vinyl monomer, and a crosslinkable monomer. An emulsion obtained by dispersing an aqueous solution of the monomer and a monomer in an organic dispersion medium with a hydrophobic surfactant and carrying out a polymerization reaction, or an emulsion containing a hydrophilic water surfactant. The same effect can be obtained by using a liquid obtained by removing water or an organic dispersion medium from such an emulsion. In the above, the water-soluble vinyl monomer includes (1)
An anionic vinyl monomer, (2) a cationic vinyl monomer or (3) a nonionic vinyl monomer is used. Examples of the anionic vinyl monomer include (meth) acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, vinylsulfonic acid, styrenesulfonic acid, itaconic acid, maleic acid, fumaric acid, and arylsulfonic acid. . Examples of the cationic vinyl monomer include neutralized salts or quaternized dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate;
And dialkylaminoalkyl (meth) acrylamides such as dimethylaminomethyl (meth) acrylamide and dimethylaminopropyl (meth) acrylamide. Examples of the nonionic vinyl monomer include (meth) acrylamide, vinyl methyl ether, vinyl ethyl ether, vinyl pyrrolidone, and the like. The crosslinkable monomer is a copolymerizable with the water-soluble vinyl monomer and includes, for example, N, N'-methylenebis (meth) acrylamide, divinylbenzene, (meth)
Examples include divinyl compounds such as vinyl acrylate, vinyl-based methylol compounds such as methylol (meth) acrylamide, vinyl aldehyde compounds such as acrolein, and methyl acrylamide glycolate methyl ether. As described above, an emulsion obtained by dispersing an aqueous solution of a water-soluble vinyl monomer and a crosslinkable monomer in a hydrophobic surfactant and an organic dispersion medium and performing a polymerization reaction is usually a polymer particle.
25-75% by weight, organic dispersion medium 20-75% by weight, hydrophobic surfactant (preferably having a hydrophilic / hydrophobic balance of HLB 3-6)
0.5 to 5% by weight and a hydrophilic surfactant (preferably HLB 10 or more) 0 to 5% by weight. The average particle size of the polymer particles of the emulsion thus prepared is usually not more than 10/1000 millimeter, and generally represents 2 to 6/1000 millimeter. When this emulsion is used as an aqueous dispersion, an example of a dispersion concentration in water is 0.01 to 5% by weight, preferably about 0.5 to 2% by weight, and this concentration is effective concentration of the emulsion and used. It is also changed depending on the nature of the water as a dispersion medium (pH value, kind and amount of salts contained, etc.). The emulsion can be used as it is, as a coating agent, or a water-swellable polymer emulsion dispersed in a hydrophobic dispersion medium obtained by dehydration treatment such as centrifugal dewatering or water evaporation. . Next, the emulsion or the aqueous dispersion thereof prepared as described above is adhered to coal or a coal deposit as a coating treatment agent. Examples of the adhesion method include dipping, spray coating, pouring, and the like, and the adhesion portion is a part or all of a coal surface (including a porous surface and a crack surface) or a gap between coal lump particles. The coating agent may be used alone or the coating agent and water may be alternately adhered. The coating treatment agent is not used directly, but may be attached to a target object after the coating treatment agent is held on a sheet or curtain as a carrier. Furthermore, the coal may be supplied to the coal being transferred, for example, supplied on a belt conveyor or from an outlet thereof together with the coal. Alternatively, the coating treatment agent may be present in the deposition site in advance, and the coal may be carried there. Further, after the deposition, it may be attached by a method such as immersion or press-fitting. The emulsion of the water-in-oil swellable polymer as the coating treatment agent of the present invention can be handled with ordinary transport pump equipment because the fluid viscosity is relatively low even as it is.
In the case of preparing a dispersion, a predetermined amount of a dispersion medium is put in an adjustment tank in advance, and a calculated amount of the emulsion is added and mixed, preferably with stirring, so as to obtain a target coating treatment solution concentration. Alternatively, a coating treatment agent at a predetermined flow rate may be added to a flowing dispersion medium through a relatively simple dispersion mixing device such as a static mixer. In this case, the flow rates of the two can be separately controlled to easily adjust the liquid concentration. The emulsion does not form “mamako” even in water, which is one of the dispersion media, and is sufficiently dispersed in a short time. Therefore, even in the case of using an adjusting tank, the emulsion is continuous as in the case of a static mixer. Target adjustment is also possible. The coating solution prepared in this way is thixotropic and can be easily handled by simple and compact transport equipment, and does not require special equipment or equipment. As described above, when the coating treatment agent of the present invention is used, there is an advantage that equipment, time, labor and cost are small in preparation and use. It is considered that the features of the coating agent of the present invention from the viewpoint of action are as follows. That is, when the particles in the water-in-oil type water-swellable polymer emulsion encounter water molecules, they undergo a water absorption reaction and swell to a volume of several hundred times or more in a very short time. This coating agent liquid is like a dispersion mixture composed of water-swollen polymer particles and a dispersion medium (eg, water), has a unique structural viscosity, and exhibits a thixotropic behavior. That is, when it is flowing, it becomes a liquid sol and behaves as a liquid having a relatively low viscosity, and this coating agent flows over the surface of the coal or enters the gap between the coal lump particles. However, when the flow stops, it immediately proceeds to a solid sol state due to thixotropic properties,
The liquid viscosity increases rapidly, and the coating agent liquid remains fixedly covering the surface of the coal or fixedly staying in the gaps between the coal lump particles. The coating agent layer is a fine particle dispersion similar to a viscous gel-like substance, so it is difficult to dry, and because it exists in a water-containing and flexible state, deformation of coal deposits and wind and rain It is much better than a conventional vinyl acetate-based or other plastic solid film in that it is hardly affected by external forces such as snow. As described above, the coating treatment agent of the present invention is present on the surface of coal or between the agglomerates thereof, and hinders contact with outside air and penetration and passage of outside air. The coating agent prevents the oxidation of coal, weathering and decomposition, heat generation, spontaneous ignition, and the like due to the oxidation by this "air blocking effect". At the same time, the coating agent is present in the form of a coating layer, thereby preventing the scattering of coal powder. When rolling is performed using a machine such as a truck, a bulldozer, or a roller, the water-in-oil type water-swellable polymer particles contained in the coating agent absorb water and have a volume of several hundred times or more. The swelling and the aggregation of the minute spherical hydrogels exert a kind of bearing effect, and thus act to reduce the frictional resistance between the coal lump particles. The method of increasing the compaction efficiency by watering according to the conventional method has been unsatisfactory because the water content of coal may be excessively increased. In comparison with this, it is clear that the coating agent of the present invention exhibits an essentially excellent effect in terms of structurally providing lubricity as described above.

【Example】

Next, the production of an emulsion of a water-in-oil type water-swellable polymer according to the present invention and an example in which the emulsion coating agent is applied to coal will be described in detail. Example A First, several examples of a method for synthesizing a water-in-oil type water-swellable polymer emulsion according to the present invention will be described. First Example: 0.15 parts by weight of NN'-methylenebisacrylamide as a crosslinking monomer and 10 as a water-soluble vinyl monomer
18 parts by weight of sorbitan monooleate having an HLB of 4.3 was added to 683 parts by weight of a 54% aqueous solution of 0% by mole ammonia-neutralized acrylic acid and 240 parts by weight of an organic dispersion medium, and emulsified with a homogenizer. After the emulsification, the mixture was transferred to a four-necked flask and purged with nitrogen gas while stirring to degas. Subsequently, a polymerization catalyst was added dropwise while purging with nitrogen gas, and polymerization was performed at a temperature of 60 ° C. After completion of the polymerization, 27 parts by weight of a polyoxyethylene lauryl ether having an HLB of 12.1 was added and stirred. The viscosity of the obtained emulsion is 330 centipoise / 25 ° C
(Measured under the conditions of a B-type viscometer, No. 2 rotor and 12 revolutions per minute), and the average particle diameter was 3.8 millimeters per thousand. Second example: 0.09 parts by weight of NN methylbisacrylamide as a crosslinkable monomer, 51% of methyl chloride quaternized dimethylaminoethyl methacrylate as an aqueous vinyl monomer
619 parts by weight of aqueous solution, 224 parts by weight of other organic dispersion medium, HLB
Using 14 parts by weight of the hydrophobic surfactant 4.3 and 25 parts by weight of the hydrophilic surfactant HLB 12.1, an emulsion was prepared in the same manner as in the first example. The viscosity of the obtained emulsion is 530 centipoise / 25
° C, (measured under the conditions of a B-type viscometer, No. 2 rotor, 12 revolutions per minute), and the average particle size was 5.1 / 1000 millimeter. Third Example: 1 volume part of emulsion and water 10 of the above synthesis example (first example)
Using 0 volume parts, each was stirred and mixed to prepare a dispersion. The resulting dispersion was a viscous liquid substance having a milky white viscosity of 5600 centipoise / 25 ° C. (measured under the condition of a B-type viscometer No. 4, 30 revolutions per minute). Fourth example: 1 volume part of emulsion and water 10 of the above synthesis example (second example)
Using 0 volume parts, each was stirred and mixed to prepare a dispersion. The resulting dispersion was a viscous liquid substance having a milky white viscosity of 2500 centipoise / 25 ° C. (measured under a condition of a B-type viscometer, No. 4 rotor, 30 revolutions per minute). Example B Next, an example in which the coating agent prepared according to the above synthesis example is applied to coal will be described. The test deposits were 2 meters high, 2 meters square on the top, 9 meters square on the ground contact surface, 93 square meters of external surface area considered as flat, (4 slopes of coal deposit and top Since it is an aggregate of agglomerates, fine irregularities exist, but this is not taken into account.)
To make a square trapezoidal deposit consisting of tons, Example N
Tests were performed on o.1 to No.3 and Comparative Examples No.1 and No.2 under the conditions described in Table 1. As a result, in Example Nos. 1 to 3 and Comparative Examples Nos. 1 and 2, the relationship between the temperature change inside the coal sediment and the number of days of accumulation was as shown in FIG. Here, the internal temperature of the deposit is measured at a height of 1 meter on a line connecting the center of the top surface and the center of the bottom surface. According to FIG. 1, in the case of Examples 1 to 3, the temperature inside the sediment after 45 days was 35 ° C. or less and there was no danger of spontaneous ignition, whereas in the case of Comparative Example 1. After 45 days, the temperature inside the sediment rose to a considerable 45 ° C, indicating that the temperature neared the danger of spontaneous ignition. Further, the effect of the coating agent of the present invention on the improvement of the compaction efficiency was examined using a roller having a diameter of 0.6 meter, a length of 0.9 meter and a weight of about 500 kg. Example that did not roll when pressed
The height of the sediment was reduced by about 22% compared to No.3. On the other hand, in the case of Comparative Example No. 2 which was rolled, the decrease in height was
About 19% of o.1 From this, the compaction effect is about 16% relative (((22−
19) ÷ 19) × 100 = 15.7%), indicating that the compaction efficiency has improved considerably.

【The invention's effect】

As described above, according to the present invention, spontaneous ignition due to oxidation of coal can be prevented. Further, since scattering of coal powder is prevented, pollution of the surrounding environment is avoided. Further, the efficiency of the compaction operation of coal deposits using machinery such as trucks and bulldozers can be improved. Therefore, the present invention can achieve effective coal handling management.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a temperature change inside a test deposit of coal and an elapsed number of days of the deposit.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-43708 (JP, A) JP-A-60-93008 (JP, A) JP-A-61-75710 (JP, A) JP-A-63-63 90510 (JP, A) JP-A-63-90537 (JP, A)

Claims (6)

(57) [Claims] In a method for controlling the handling of coal by applying a coating agent to a large number of coals, it is preferable to use an emulsion of a water-in-oil type water-swellable polymer or an aqueous dispersion thereof as the coating agent. Characteristic coal handling management method. 2. An emulsion of a water-in-oil type water-swellable polymer comprising one or more of a water-soluble anionic vinyl monomer, a cationic vinyl monomer and a nonionic vinyl monomer. 2. The method according to claim 1, wherein the emulsion is an emulsion obtained by dispersing an aqueous solution of a polymer and a crosslinkable monomer in an organic dispersion medium with a hydrophobic surfactant and performing a polymerization reaction. . 3. The method according to claim 1, wherein a hydrophilic surfactant is present in the emulsion or a dispersion medium thereof. 4. The method for managing coal handling according to claim 1, wherein the handling management of coal is prevention of spontaneous combustion of coal. 5. The coal handling management method according to claim 1, wherein the management of coal is prevention of scattering of coal powder. 6. The coal handling system according to claim 1, wherein the management of the handling of the coal is to improve the efficiency of the compaction operation of the coal sediment using a machine such as a truck and a bulldozer. Handling management method.