KR20230162848A - Manufacturing system of anti-spontaneous combustion agent for coal using a ultrasonic wave, and manufacturing method thereof, and anti-spontaneous combustion agent for coal manufactured by same - Google Patents

Abstract

The present invention relates to a production system for a spontaneous combustion inhibitor for coal using ultrasonic waves, a method for manufacturing a spontaneous combustion inhibitor for coal, and a spontaneous combustion inhibitor for coal manufactured using the same. The present invention relates to a method of producing a spontaneous combustion inhibitor for coal using ultrasonic irradiation mixing method. It facilitates the mixing and mixing of solid raw materials such as blast furnace slag and liquid ethylene-based resin additives, and hardens immediately after spraying on the surface of the coal pile, so that the spontaneous combustion inhibitor for coal hardens on the surface without flowing into the pores of the coal pile. It effectively prevents spontaneous combustion by preventing penetration of oxygen and moisture into the coal pile at a depth of 0.5 to 1.5 m, which is the point where spontaneous combustion occurs.

Description

Manufacturing system for spontaneous combustion inhibitors for coal using ultrasonic waves, manufacturing method thereof, and spontaneous combustion inhibitors for coal manufactured using the same COMBUSTION AGENT FOR COAL MANUFACTURED BY SAME}

The present invention relates to a production system for a spontaneous combustion inhibitor for coal using ultrasonic waves to prevent spontaneous combustion of low-grade coal, a manufacturing method thereof, and a spontaneous combustion inhibitor for coal manufactured using the same.

Coal is used as a raw material for thermal power plants around the world due to its abundant reserves, low price, and stability of supply. Recently, the proportion of coal-fired power as a power source is increasing due to increased demand for electricity due to electric vehicles, concerns about the risks of nuclear power generation, and the low expansion of domestic renewable energy power generation. Accordingly, the amount of coal imported is increasing, and the import proportion and amount of low-rank coal, which has many problems with spontaneous combustion, clinker generation, and composition, is also increasing significantly.

In general, in the case of a 500 MW standard coal-fired power plant, fuel coal is usually used after 1 to 3 months of coal storage, but in the coal storage area, there is a problem of spontaneous combustion and scattering of some pulverized coal among the stored coal. In addition, when constructing a new coal-fired power plant, not only is it difficult to secure land for the construction of a coal storage facility, but the construction of a new coal storage facility is also difficult due to friction and complaints from nearby residents and environmental groups. To solve this problem, when constructing a new coal storage facility, it is constructed indoors. However, it is not only impossible to fundamentally prevent the problem of spontaneous combustion of low-grade coal even in an indoor type storage facility, but also once spontaneous combustion occurs, spontaneous combustion occurs. Management and response tasks are often more difficult.

Low Rank Coal (LRC) is divided into peat, brown coal, lignite, sub-bituminous coal, bituminous coal, and anthracite, in order from lowest to highest. Bituminous coal is further divided into low-volatile, medium-volatile, and high-volatile bituminous coal, and anthracite is divided into semi-anthracite, anthracite, meta-anthracite, and graphitic anthracite. Among these, low-grade coal (LRC) generally refers to brown coal to sub-bituminous coal, and bituminous coal is classified as high-grade coal (Hard Coal; High Rank Coal).

Low-grade sub-bituminous coal has many pores and a lot of volatile matter, which is a peripheral hydrocarbon in its chemical structure, so the temperature rises due to the accumulation of adsorption heat due to adsorption and desorption of moisture, and oxidation reactors, Hydroxyl groups (-), account for a significant amount of the volatile matter. OH), Carboxy group (-COOH), Carbony group (-C=O) humic acid polymer [(C ₉ H ₉ NO ₆ ^- )n] increases the temperature inside the pore by oxidation reaction. It may also cause spontaneous combustion.

As shown in Figure 1, when spontaneous combustion occurs in coal, ignition gases such as carbon monoxide (CO), carbon dioxide (CO ₂ ), hydrogen (H ₂ ), and water vapor (H ₂ O) are released from the initial low temperature that is not visible to the naked eye. When high-temperature spontaneous combustion of over 200℃ occurs in earnest, not only is the heat loss of the coal itself (loss rate approximately 5.85% or less), but also 66 types of organic compounds and fumes, including benzene, toluene, and acetic acid, are used in the coal storage area. The environment deteriorates and this causes civil complaints in the surrounding area, and there is also a risk of major damage to the equipment, such as fire and dust explosion in the pulverizer system, during the transportation of coal using conveyor belts. Additionally, heat continues to accumulate and a flame occurs when the temperature reaches 300°C to 500°C.

Existing countermeasures against spontaneous combustion can be broadly divided into two categories: The first is to block contact with moisture or oxygen in the atmosphere by applying/spraying a coating or spraying agent using a cement solidifying agent or polymer hardening agent on the coal pile. The second method is to adsorb oil on dry coal at high temperature or modify the surface through compression or molding.

However, in the case of the first method, not only is it difficult to fundamentally block the infiltration of moisture and oxygen as it is prone to detachment in rainfall and strong winds, but it can also cause fine powder and combustion problems when inputting it into the boiler. In addition, the second method requires too much energy and additional equipment to modify the surface reforming of low-grade coal, so it is not a very effective method considering economic feasibility and has not been applied to actual coal-fired power plants.

In addition, in Korean Patent Publication No. 10-2017-0035423, in order to effectively prevent and suppress the phenomenon of spontaneous combustion in coal storage areas where coal is handled and stored on a large scale, spontaneous combustion is applied to the surface of the coal pile when low-grade coal is stored in the coal storage area. A method for manufacturing an inhibitor and a method for preventing spontaneous combustion of low-grade coal using the same were presented. However, due to the nature of conventional spontaneous combustion inhibitors, the concentration of solid additives and hardeners added for curing hardens immediately when sprayed and applied to the coal pile is high, so they are not mixed evenly due to high viscosity during the raw material mixing process and harden before being applied to the coal pile. A throwing away problem arose.

Therefore, there is a need for a new method that can fundamentally solve the problem of ignition of coal unloaded at a high temperature and effectively suppress spontaneous combustion without causing additional problems like the above methods.

Korean Patent Publication No. 10-2017-0035423

Considering the above problems, the purpose of the present invention is to provide a production system for a spontaneous combustion inhibitor for coal using ultrasonic waves to effectively prevent and suppress the spontaneous combustion phenomenon in coal storage areas where coal is handled and stored on a large scale.

In addition, it is intended to provide a method for manufacturing a spontaneous combustion inhibitor for coal using the ultrasonic wave-based production system for a spontaneous combustion inhibitor for coal, and a spontaneous combustion inhibitor for coal manufactured through this manufacturing method, which is applied to the surface of a pile of high-combustion coal in a coal storage facility. The purpose.

In order to achieve the above object, the manufacturing system for the spontaneous combustion inhibitor for coal of the present invention includes a raw material storage unit for the spontaneous combustion inhibitor for coal, and a space formed therein to accommodate the raw materials supplied from the raw material storage unit. It is characterized by comprising a mixing tank, a stirrer located at the inner center of the mixing tank and rotating to mix the raw materials, and an ultrasonic generator connected to the mixing tank to irradiate ultrasonic waves to the raw materials.

In the system for manufacturing a spontaneous combustion inhibitor for coal of the present invention, the mixing tank may include an inlet through which the raw material delivered from the raw material storage unit flows in, and an outlet through which the spontaneous combustion inhibitor for coal manufactured from the mixing tank is discharged.

In the production system for a spontaneous combustion inhibitor for coal of the present invention, the raw material storage unit includes a solid raw material storage tank that stores one or more selected from coal ash, incineration ash, and slag, ethylene vinyl acetate, asphalt, urea nitrate, and an ethylene-based resin liquid additive storage tank that stores one or more selected from cellulose, and a water storage tank.

In the system for producing a spontaneous combustion inhibitor for coal of the present invention, the agitator is provided at the inner center of the mixing tank and has a rotating shaft that transmits rotational power, and receives rotational power from the rotating shaft and rotates to mix the raw materials. It may be provided and include a plurality of rotating blades symmetrically formed with respect to the rotation axis.

The system for producing a spontaneous combustion inhibitor for coal of the present invention includes a discharge line through which the spontaneous combustion inhibitor for coal manufactured in the mixing tank is discharged, and a nozzle connected to one end of the discharge line to spray the spontaneous combustion inhibitor for coal into the target coal. It may further include a spraying unit that sprays through the sprayer.

The method for manufacturing a spontaneous combustion inhibitor for coal of the present invention to achieve another purpose includes the steps of (a) adding water and an ethylene-based resin liquid additive as liquid raw materials inside the mixing tank, (b) adding coal ash to the inside of the mixing tank. , introducing solid raw materials containing at least one selected from incineration ash and slag, and (c) irradiating ultrasonic waves to the raw materials introduced into the mixing tank and simultaneously stirring them.

In the method for producing a spontaneous combustion inhibitor for coal of the present invention, step (c) involves irradiating the raw material with an ultrasonic frequency of 150 to 300 kHz for 10 to 20 minutes, and simultaneously stirring the raw material at 200 rpm to 300 rpm. desirable.

In the method for producing a spontaneous combustion inhibitor for coal of the present invention, after step (c), a spraying step of spraying the prepared spontaneous combustion inhibitor for coal onto the target coal pile using a spray nozzle may be further included.

In addition, the spontaneous combustion inhibitor for coal of the present invention is manufactured through a method for manufacturing a spontaneous combustion inhibitor for coal using the above-described spontaneous combustion inhibitor production system for coal.

Specifically, the spontaneous combustion inhibitor for coal of the present invention includes solid raw materials containing at least one selected from coal ash, incineration ash, and slag, an ethylene-based resin liquid additive, and water.

The spontaneous combustion inhibitor for coal of the present invention contains 55% to 65% by weight of the solid raw material, 4.5% to 6.5% by weight of the ethylene-based resin liquid additive, and the water based on 100% by weight of the total spontaneous combustion inhibitor for coal. It is preferable that it consists of 30.5% by weight to 40.5% by weight.

The solid raw material may include 15% to 40% by weight of calcium oxide and 5% to 25% by weight of unburned carbon, based on 100% by weight of the solid raw material.

The ethylene-based resin liquid additive is 20% to 30% by weight of ethylene vinyl acetate, 60% to 70% by weight of asphalt, and urea nitrate (Urea), based on 100% by weight of the ethylene-based resin liquid additive. nitrate) at 0.002% by weight to 2% by weight, and cellulose (Cellulose) at 5% by weight to 20% by weight.

Coal plays an important role as a source of energy due to its abundant reserves, low price, and stability of supply. However, as the proportion of imported low-grade coal has recently increased, spontaneous combustion problems have also occurred very frequently, so coal storage sites that store and handle coal on a large scale are experiencing severe problems. By applying the spontaneous combustion inhibitor for coal manufactured using the invention's production system for the spontaneous combustion inhibitor for coal, a great effect can be achieved in preventing spontaneous combustion of low-grade coal and storing it for a long period of time.

The production system of the spontaneous combustion inhibitor for coal of the present invention uses solid raw materials such as coal ash from power plants, household waste incineration ash, or blast furnace slag as the main ingredient through an ultrasonic irradiation mixing method to smoothly mix and blend the ethylene-based resin liquid additive. It is sprayed on the surface of the coal pile and hardens immediately, so that the spontaneous combustion inhibitor for coal hardens on the surface without flowing into the pores of the coal pile, allowing oxygen and moisture to penetrate into the coal pile at a depth of 0.5 to 1.5 m, which is the point where spontaneous combustion occurs. To prevent.

In the above spontaneous combustion inhibitor for coal, the solid raw material acts as an insulator after being applied to the surface of the target coal pile, and calcium oxide among the raw materials reacts with silicon dioxide (SiO ₂ ) and aluminum oxide (Al ₂ O ₃ ), which are the main components of coal ash and incineration ash. This forms CSH (CaO-SiO ₂ -H ₂ O) and CAH (CaO-Al ₂ O ₃ -H ₂ O) hydrates and increases the bond angle while curing, thereby preventing detachment or cracking due to external force, thereby preventing coal piles. It can prevent oxygen and moisture from penetrating inside.

Figure 1 schematically shows the spontaneous combustion mechanism of coal in a coal storage facility.
Figure 2 is a configuration diagram of a system for manufacturing a spontaneous combustion inhibitor for coal according to an embodiment of the present invention.
Figure 3 shows the configuration of the manufacturing unit and the spraying unit in the production system for a spontaneous combustion inhibitor for coal according to an embodiment of the present invention.
Figure 4 is a diagram showing external conditions for computerized analysis of a coal stockpile according to an embodiment.
Figure 5 shows the formation of a coal stockpile grid system according to one embodiment.
Figure 6 is a simulation result of the ignition prevention effect before and after application of a spontaneous combustion inhibitor for coal.
Figure 7 is a diagram showing the configuration of a device simulating spontaneous combustion of coal.
Figures 8 and 9 are graphs showing the results of monitoring oxygen concentration inside the coal pile.
Figures 10 and 11 are graphs showing the results of monitoring the internal temperature of the coal pile.
Figure 12 is a demonstration scene of a spontaneous combustion preventer for coal piles according to an embodiment of the present invention.
Figure 13 shows the installation of a temperature change measurement sensor inside the coal pile after unloading the coal from the coal storage.
Figure 14 is a plan view of the installation of the internal temperature measurement sensor after unloading the ignition coal at the coal storage site and an indication of the location of the injection experiment.
Figure 15 is a graph showing the results of temperature increase at a depth of 1 m inside depending on whether or not a spontaneous combustion inhibitor for coal is applied.
Figures 16 and 17 show the surface condition of the spontaneous combustion inhibitor for coal and the removal of the TC (thermocouple) support matrix after completing the 30-day demonstration period.

Hereinafter, the production system for the spontaneous combustion inhibitor for coal according to the present invention, its manufacturing method, and the spontaneous combustion inhibitor for coal manufactured using the same will be described in detail with reference to the attached drawings. However, this is a preferred embodiment and the scope of the present invention is not necessarily limited thereto.

Figure 2 shows the configuration of a production system for a spontaneous combustion inhibitor for coal according to an embodiment of the present invention. As shown in Figure 2, the production system for a spontaneous combustion inhibitor for coal of the present invention largely consists of a raw material storage unit 20. , a manufacturing unit 30, and an injection unit 40.

The raw material storage unit 20 stores raw materials for the composition of the spontaneous combustion inhibitor for coal of the present invention, and is configured to separate solid raw materials and liquid raw materials of the spontaneous combustion inhibitor for coal, and any selected from coal ash, incineration ash, and slag. A solid raw material storage tank storing one or more solid raw material storage tanks, an ethylene-based resin liquid additive storage tank storing one or more selected from ethylene vinyl acetate, asphalt, urea nitrate, and cellulose, and It may be configured to include a water storage tank.

Specifically, a water storage tank (1), which is most of the components of spontaneous combustion prevention paper for coal, a control valve (2) that controls the water supply to the water storage tank (1), and an asphalt storage tank (3), which is a liquid additive, and storage. A control valve (4) that controls the transfer amount of the tank, an EVA storage tank (5), which is an ethylene-based resin additive, and a control valve (6) that controls the transfer amount of the storage tank, and Urea Nitrate, an ethylene-based resin curing aid. ) The storage tank (7) and the control valve (7) that controls the transfer amount of the storage tank, the liquid cellulose storage tank (9) and the control valve (10) that controls the transfer amount of the storage tank and the liquid additive are first pre-processed. It consists of an ethylene-based resin liquid additive mixing tank (11) for mixing and blending, and a control valve (12) of the ethylene-based resin liquid additive mixing tank (12) that controls the transfer amount of the ethylene-based resin liquid additive mixing tank (11).

A solid raw material storage tank (13) that stores one or more selected from coal ash, incineration ash, and slag such as high-calcium coal ash, domestic waste incineration ash (ash), or blast furnace slag powder as a powdered spontaneous combustion inhibitor, and a certain amount of powdered solid raw materials are supplied. Powder ignition control consisting of a screw valve (14) to increase the pozzolanic activity of the powder phase, a calcium hydroxide (Ca(OH) ₂ ) storage tank (15) to increase the pozzolanic activity of the powder phase as needed, and a screw valve (16) to precisely control the amount of calcium hydroxide transferred. It is characterized by being composed of a fat ingredient supply section.

In this way, the raw materials supplied from the raw material storage unit 20 are transferred to the manufacturing unit 30 through the liquid raw material supply unit 17 and the solid raw material supply unit 18, and the manufacturing unit ( In 30), the spontaneous combustion inhibitor for coal is completely mixed and mixed by irradiating ultrasonic waves, and the manufactured spontaneous combustion inhibitor for coal is transferred to the spray unit (40) and applied to the surface of the coal pile through the spray unit (40). Hardening prevents coal from contact with external heat, air, and moisture.

Figure 3 shows the configuration of the manufacturing unit and the spraying unit in the production system for a spontaneous combustion inhibitor for coal according to an embodiment of the present invention.

As shown in FIG. 3, the manufacturing unit 30 is a mixing tank 27 that forms a space therein to accommodate the raw materials supplied from the raw material storage unit 20 to manufacture a spontaneous combustion inhibitor for coal using ultrasonic waves. is formed, a stirrer located at the inner center of the mixing tank 27 and rotating to mix the raw materials, and an ultrasonic generator 22 connected to the side of the mixing tank to irradiate ultrasonic waves to the raw materials. Includes.

The specific configuration of the manufacturing unit 30 consists of the components of the spontaneous combustion inhibitor for coal supplied through the liquid raw material supply unit 17 and the solid raw material supply unit 18 formed at the inlet through which the raw material delivered from the raw material storage unit 20 flows. A mixing tank 27 for mixing, an ultrasonic generator 22 formed on the side of the mixing tank 27 to generate ultrasonic waves for mixing the spontaneous combustion inhibitor, and a mixing tank 27 formed at the lower part of the mixing tank 27. It includes an insulating part (23) that absorbs ultrasonic vibrations and supports the weight, an outer wall that protects the mixing tank (27) and the ultrasonic generator (22), and is located at the inner center of the mixing tank (27) to prevent spontaneous combustion. The stirrer for mixing ingredients includes a rotating motor 21, a rotating shaft 25 that transmits the rotating power received from the rotating motor 21, and a rotating power received from the rotating shaft 25 to rotate to mix the raw materials. It includes a plurality of rotating blades (24) formed symmetrically with respect to the rotating axis (25). An outlet 26 through which the manufactured spontaneous combustion inhibitor for coal is discharged is formed in the lower part of one side of the mixing tank 27.

In the system for producing a spontaneous combustion inhibitor for coal, the injection unit 40 has a discharge line 31 through which the spontaneous combustion inhibitor for coal manufactured in the production unit 30 is discharged, and the spontaneous combustion inhibitor for coal is discharged along the discharge line 31. The spontaneous combustion inhibitor for coal is transported along the injection line 34 by the injection pump 32, which suctions the spontaneous combustion inhibitor control valve 33, through the injection nozzle 35 connected to one end of the injection line 34. Spray on the surface of the target coal pile.

The method of manufacturing a spontaneous combustion inhibitor for coal using a spontaneous combustion inhibitor manufacturing system includes the steps of (a) adding water and an ethylene-based resin liquid additive as liquid raw materials inside the mixing tank, (b) coal ash inside the mixing tank, It may include the step of introducing solid raw materials containing at least one selected from incineration ash and slag, and (c) irradiating ultrasonic waves to the raw materials introduced into the mixing tank and simultaneously stirring them.

In step (a), the liquid raw materials stored in the water storage tank (1) and the ethylene-based resin liquid additive mixing tank (11) in the raw material storage unit (20) of the coal spontaneous combustion inhibitor production system are manufactured at a set content. It is put into the mixing tank (27) of the unit (30).

In step (b), the solid raw materials stored in the solid raw material storage tank 13 in the raw material storage unit 20 of the coal spontaneous combustion inhibitor manufacturing system are stored in the mixing tank 27 of the manufacturing unit 30 at a set content. Put it in.

In step (b), calcium hydroxide (Ca(OH) ₂ ) stored in the calcium hydroxide storage tank 15 to increase the pozzolanic activity of the powder phase as needed along with the solid raw materials is added to the mixing tank 27 of the manufacturing unit 30. ) can be added internally.

Step (c) is a step of evenly mixing and mixing the raw materials of the spontaneous combustion inhibitor for coal introduced through steps (a) and (b). Using an ultrasonic generator, the raw materials are subjected to ultrasonic waves of 150 to 300 kHz for 10 minutes. Irradiate for minutes to 20 minutes, and at the same time, stir the raw materials at 200 rpm to 300 rpm using a stirrer.

The high-power ultrasound applied in step (c) has the ability to induce a chemical effect, and the source of the ultrasonic chemical effect in the liquid phase is the phenomenon of acoustic cavitation. The acoustic cavitation phenomenon is a repetitive process of compression and expansion in order, including the nucleation stage of the cavitation bubble, the growth stage of the created cavitation bubble, and the collapse stage of the cavitation bubble grown in an unstable state. It consists of three different but consecutive steps.

In particular, in the present invention, high energy is present by irradiating ultrasonic waves in water at a frequency of 150 to 300 kHz and an irradiation time of 10 to 20 minutes while mixing at a stirring speed of 200 rpm to 300 rpm, more preferably 250 rpm, using a stirrer. Inside the bubble, water molecules are decomposed into OH radicals and hydrogen radicals, increasing the diffusion and penetration characteristics of the ethylene resin liquid additive, which is a hardener solution, while delaying the bonding speed between molecules, making it possible to use coal in the manufacturing department where mixing is performed during the ultrasonic irradiation process. By preventing the spontaneous combustion inhibitor from hardening, the manufactured spontaneous combustion inhibitor for coal is sprayed smoothly through the injection nozzle.

After step (c) in the method for producing a spontaneous combustion inhibitor for coal according to the present invention, the produced spontaneous combustion inhibitor for coal has a discharge line 31 connected to the outlet 26 of the mixing tank 27 by the injection pump 32. ) and further includes a spraying step of spraying the target coal pile through the spray nozzle 35 through the spray line 34 by the autoignition preventer control valve 33.

The spraying step prevents spontaneous ignition of low-grade coal by applying a spontaneous ignition inhibitor for coal only to a height of about 30 to 40% from the bottom to the top of the surface of the ignition cluster pile.

Generally, a reclaimer is used when storing coal in a coal storage yard. At this time, the coal naturally falls, and the upper part of the coal pile is mixed with coarse-grained coal and fine-grained coal, and the lower part of the coal pile is mostly coarse-grained coal. This piles up. If the coal particles are thick, the pores between the coal particles become larger, increasing the probability of contact between the surface of the coal and oxygen in the atmosphere. In fact, it was found that spontaneous combustion frequently occurred at the bottom of the coal pile at coal-fired power plant storage sites.

Therefore, when applying a spontaneous combustion inhibitor for coal to a pile of coal during the spraying stage, it is not applied to the entire surface but is applied around the area where spontaneous combustion occurs frequently, thereby effectively preventing spontaneous combustion by using a relatively small amount of flame retardant. can do.

A manufacturing system for spontaneous combustion inhibitors for coal as described above, and The spontaneous combustion inhibitor for coal manufactured through the method of manufacturing a spontaneous combustion inhibitor for coal includes solid raw materials using solid waste such as power plant landfill ash, household waste incineration ash, or blast furnace slag, an ethylene-based resin liquid additive, and water.

In the case of desulfurization facilities in coal-fired boilers, household waste incinerators, and steel mill blast furnace slag, coal ash, incineration ash, and slag containing more than 10% of calcium oxide (CaO) are produced.

Therefore, calcium oxide (CaO) components such as coal ash, incineration ash, and slag, which are solid wastes generated from incinerators and steel mills, which are used as solid raw materials for the spontaneous combustion inhibitor for coal of the present invention, include silicon dioxide (SiO ₂ ), which is the main component of coal ash, and It reacts with aluminum oxide (Al ₂ O ₃ ) to form CSH (CaO-SiO ₂ -H ₂ O) and CAH (CaO-Al ₂ O ₃ -H ₂ O) hydrates, which are cured and solidified to increase the bonding strength of the spontaneous combustion inhibitor. By increasing it, it prevents detachment and cracks caused by external forces and prevents oxygen and moisture from penetrating into the coal pile.

The solid raw material of the spontaneous combustion inhibitor for coal of the present invention is highly combustible coal ash and household waste incineration ash that are landfilled due to the unburned carbon (LOI; Loss On Ignition) content of 5% or more according to the coal ash recycling standard, which can be easily obtained from coal-fired power plants and incinerators. Alternatively, it has the feature of using soot ash. Highly unburned coal ash is sprayed on the coal pile in the form of a spontaneous combustion inhibitor and then reburned in the boiler together with the coal to recover fuel loss due to unburned carbon. The reburned unburned carbon is REC (Renewable Energy), a renewable energy supply certificate. Energy Certificate) certification. At this time, if regular coal ash is used instead of high-unburned coal ash, the fuel loss (unburned content) is not recovered and only coal ash is put into the boiler furnace, so REC certification cannot be obtained.

In addition, new 1,000 MW coal-fired boilers that were recently built and operated are equipped with low nitrogen oxide (NOx) burners, which results in the ash containing a large amount of soot. Ash with a high soot content has the problem of creating black cement when recycled into cement, making it impossible to recycle coal ash. Therefore, this soot ash is used as a raw material for the spontaneous combustion inhibitor for coal of the present invention and is reintroduced into the boiler to cause the soot component to burn once again.

The solid raw materials of the spontaneous combustion inhibitor for coal include calcium oxide and unburned carbon, and based on 100% by weight of the total solid raw materials, 15% to 40% by weight of calcium oxide and 5% to 25% by weight of unburned carbon. It is desirable to include it as a percentage.

Coal ash, incineration ash, and slag, which are used as solid raw materials for spontaneous combustion inhibitors for coal, have their own insulating properties, so when spontaneous combustion inhibitors containing them are sprayed on the coal pile, a layer is formed on the surface of the coal pile, forming a layer on the outside of the coal pile. It acts as an insulator by preventing heat from the atmosphere from being transmitted to the inside of the coal pile.

The spontaneous combustion inhibitor for coal uses an ethylene-based resin liquid additive so that it can be fixed without being lost due to rain or strong wind after being sprayed on the surface of the coal pile.

Here, the ethylene-based resin liquid additive is selected from ethylene vinyl acetate, asphalt, urea nitrate, and cellulose, and is used alone or in combination with hydroxypropyl methylcellulose. And the content is 20% to 30% by weight of ethylene vinyl acetate, 60% to 70% by weight of asphalt, and urea nitrate, based on 100% by weight of the total ethylene resin liquid additive. ) 0.002% to 2% by weight, and 5% to 20% by weight of hydroxypropyl methylcellulose as cellulose.

In addition, products manufactured based on the ingredients of the ethylene resin liquid additive can be mixed and used as raw materials, and liquid additives mixed with asphalt available on the market can also be used.

The dilution ratio of the ethylene-based resin liquid additive of the present invention can be appropriately adjusted to suit the field conditions, and the spontaneous combustion inhibitor for coal is applied to the surface of the coal pile by mixing high-carbon coal ash, asphalt, and the ethylene-based resin liquid additive. It hardens and has the characteristic of not detaching or cracking due to rainfall or strong winds.

The spontaneous combustion inhibitor for coal of the present invention contains 55% to 65% by weight of the solid raw material, 4.5% to 6.5% by weight of the ethylene-based resin liquid additive, and the water based on 100% by weight of the total spontaneous combustion inhibitor for coal. It is preferable that it consists of 30.5% by weight to 40.5% by weight.

Hereinafter, the characteristics and effects of the spontaneous combustion inhibitor for coal of the present invention will be described in detail through experimental examples of the present invention.

Experimental Example 1. Evaluation of mixing, spraying, and curing characteristics of spontaneous combustion inhibitors for coal

Experimental Example 1 evaluated the mixing, spraying, and curing characteristics of the spontaneous combustion inhibitor for coal according to the raw material content ratio, presence of ultrasonic irradiation, frequency intensity of ultrasonic waves, and irradiation time.

Table 1 below shows that, as shown in the solid raw material composition table, a certain amount of coal ash or household waste incineration ash, slag powder or soot ash is prepared, and then a certain amount of ethylene resin liquid additive and water are added to prepare the raw material for spontaneous combustion inhibitor for coal.

Ashes Chemical compositions(n=30) SiO ₂ Al ₂ O _{3 Fe2O3 _} CaO MgO Na ₂ O _K2O SO ₃ TiO ₂ P ₂ O ₅ LOI note 5%Ca 49.72 24.85 4.21 4.99 2.26 1.66 1.59 0.22 0.66 0.14 9.7 coal ash 29%Ca 37.33 17.63 3.13 29.2 1.68 1.01 1.25 0.15 0.6 0.17 7.85 Incinerator 41%Ca 26.7 13.95 3.67 41.05 1.32 1.23 1.02 0.26 0.45 0.47 9.88 slag

Table 2 below evaluates the content of solid raw materials, ease of mixing with or without ultrasonic waves, nozzle spray suitability, and curing speed. The experimental conditions are 100% by weight of all solid raw materials for 100% by weight of spontaneous combustion inhibitors for coal. Regarding this, the coal ash containing 5% by weight of calcium oxide (CaO) was changed to the range of 50% by weight to 65% by weight, and 5% by weight of ethylene resin liquid additive was added as a liquid raw material, where the ethylene resin liquid additive is the total ethylene resin. Based on 100% by weight of liquid additive, it consists of 25.0% by weight of ethylene vinyl acetate (EVA), 65.5% by weight of asphalt, 8.0% by weight of cellulose, and 1.5% by weight of urea nitrate, and solid raw materials. A spontaneous combustion inhibitor for coal was prepared by adjusting the water to a range of 30% by weight to 45% by weight according to the ratio.

The mixing conditions for the prepared spontaneous combustion inhibitor raw materials for coal were that ultrasonic waves were added at a frequency of 150 kHz and an irradiation time of 10 min. Variable tests were conducted depending on whether or not the irradiation was performed, and in all cases, the stirrers (21, 24, and 25) were operated at a speed of 250 rpm. It was put into operation.

division Ease of mixing Nozzle spray
fitness curing speed final selection Content (% by weight) Ultrasound or not 65 non-ultrasound error error incongruity × ultrasonic wave fitness incongruity incongruity × 60 non-ultrasound amount error fitness × ultrasonic wave Good Good fitness ○ 55 non-ultrasound incongruity incongruity Good × ultrasonic wave fitness fitness Good ○ 50 non-ultrasound fitness fitness error × ultrasonic wave fitness fitness incongruity ×

As shown in Table 2 above, in all cases of non-ultrasonic conditions without operating ultrasonic waves, hardening began during the mixing process when the solid raw material content ratio was 50% by weight or more, making mixing and spraying unsuitable. When ultrasonic waves were irradiated, If the content of coal ash, which is a solid raw material, is less than 50% by weight, the spontaneous combustion inhibitor becomes too diluted and when applied to the surface of the coal pile, not only does it escape through the pores and cannot remain on the surface, but also the curing speed of the spontaneous combustion inhibitor is delayed. do. On the other hand, when the content ratio of solid raw materials was more than 65% by weight, the spontaneous combustion inhibitor was so thick that spraying using a nozzle was almost impossible.

Therefore, the conditions in which ultrasonic waves were operated with a solid raw material content ratio of 55% to 60% by weight were finally selected.

In the final selection shown in Tables 2 to 5 of this specification, '○' means that the performance conditions are finally selected, and conversely, '×' means that the performance conditions are not finally selected.

Table 3 below evaluates the mixing, spraying, and curing characteristics according to the frequency intensity and irradiation time of ultrasonic waves. The experimental conditions are solid raw materials, 60 wt% of coal ash containing 5 wt% of calcium oxide (CaO) based on 100 wt% of the total solid raw materials. , 5% of ethylene-based resin liquid additive was added to the liquid sample, and the ethylene-based resin liquid additive consisted of the same ingredient content as in Table 2 above, and 35% by weight of water. Meanwhile, the mixing conditions were changed to an ultrasonic wave frequency of 50 kHz to 400 kHz and an irradiation time of 5 to 30 minutes, and a variable experiment was conducted according to the ultrasonic irradiation time. In all cases, the stirrer was operated at a speed of 250 rpm.

division Ease of mixing Nozzle spray
fitness curing speed final selection Frequency (kHz) Time (minutes) 50 5 error error incongruity × 10 incongruity incongruity incongruity × 20 incongruity incongruity incongruity × 30 fitness fitness fitness ○ 150 5 fitness fitness fitness ○ 10 Good Good fitness ○ 20 Good Good Good ○ 30 Good Good Good ○ 300 5 fitness fitness fitness ○ 10 Good Good Good ○ 20 Good Good Good ○ 30 Good Good Good ○ 400 5 fitness fitness fitness ○ 10 Good Good Good ○ 20 Good Good Good ○ 30 Good Good fitness ○

As shown in Table 3 above, when an ultrasonic frequency of 150 kHz or higher was added to the raw material of the spontaneous combustion inhibitor for coal, the mixing, spraying, and post-spray curing characteristics were found to be suitable. However, when the ultrasonic waves are increased above 400 kHz, the surrounding noise increases and the reaction device screw loosening phenomenon occurs, and the range of 150 kHz to 300 kHz is considered appropriate for the durability of the mixing device.

Table 4 below evaluates the mixing, spraying, and curing characteristics by content of solid raw materials and calcium oxide (CaO) for 100% by weight of total solid raw materials. The experimental conditions were changed to a range of 50% to 65% by weight of the solid raw material containing 5% to 41% by weight of calcium oxide (CaO) in Table 1, and 5% by weight of an ethylene resin liquid additive was added to the liquid sample. The composition of the ethylene-based resin liquid additive was the same as under the conditions in Table 3, and the water content was adjusted to 30% by weight to 45% by weight depending on the ratio of solid raw materials. The optimal mixing conditions as shown in Tables 2 and 3 were an ultrasonic wave frequency of 150 kHz and an irradiation time of 10 minutes, and in all cases, the mixture was mixed at a stirrer speed of 250 rpm.

division Ease of mixing Nozzle spray
fitness curing speed final selection Solid raw material content (% by weight) CaO
(weight%) 65 5 Good Good incongruity × 29 Good Good fitness ○ 41 Good Good fitness ○ 60 5 Good Good fitness ○ 29 Good Good Good ○ 41 Good Good Good ○ 55 5 fitness fitness Good ○ 29 fitness fitness Good ○ 41 Good fitness fitness ○ 50 5 fitness fitness incongruity × 29 fitness fitness incongruity × 41 fitness fitness fitness ○

As shown in Table 4 above, the mixing, irradiation, and curing properties were found to be suitable even when all calcium oxide (CaO)-containing solid raw materials were used in the range of 55% to 60% by weight. Alternatively, even in the case of 50% by weight or less, it was found to be suitable if the calcium oxide (CaO) content was 41% by weight or more.

Table 5 below shows the mixing, spraying and curing characteristics while changing the coal ash containing 29% by weight of calcium oxide (CaO) and the ethylene resin liquid additive with 60% by weight of solid raw materials in the range of 3.75% by weight to 8.0% based on 100% by weight of total solid raw materials. was evaluated, and the ethylene-based resin liquid additive was the same as the conditions in [Table 3], and water was adjusted to the range of 32.0% by weight to 36.25% depending on the ratio of the ethylene-based resin liquid additive. Meanwhile, the mixing conditions were an ultrasonic wave frequency of 150 kHz and an irradiation time of 10 minutes, shown as the optimal conditions in Tables 2 and 3, and in all cases, mixing was performed at a stirrer speed of 250 rpm.

Ethylene-based resin liquid additive
(weight%) Ease of mixing Nozzle spray
fitness curing speed final selection 8.00 error error fitness × 7.25 error fitness fitness × 6.50 fitness fitness fitness ○ 5.25 Good Good Good ○ 4.5 Good Good fitness ○ 3.75 fitness fitness error ×

As shown in Table 5 above, the ethylene-based resin liquid additive in the liquid raw materials is appropriately in the range of 4.5% to 6.5% by weight based on 100% by weight of the total coal spontaneous combustion inhibitor, and the content of the ethylene-based resin liquid additive is 6.5% by weight. If the percentage is exceeded, the problem of mixing liquid raw materials becomes difficult, and as the content increases, the unit price of the spontaneous combustion inhibitor increases, making it less economical.

On the other hand, if the ethylene resin liquid additive content is less than 4.5% by weight, the curing speed of the spontaneous combustion inhibitor is delayed and the viscosity is lowered, so it is not suitable because it causes problems such as being washed away by rain and poor field applicability.

Experimental Example 2. Evaluation of ignition prevention effect according to application of spontaneous combustion inhibitor for coal

Experimental Example 2 was conducted to determine the ignition prevention effect after applying a spontaneous combustion inhibitor to the surface of a coal storage pile (stockpile) through computer analysis. First, external conditions similar to those of an actual coal stockpile were created, and a grid system of similar size was created.

Since most spontaneous ignition phenomena occur between 0.5m and 1.5m on the surface of the coal stockpile, where external air relatively easily flows in, when forming the grid system of the coal stockpile, the grid system is set more densely on the surface area and a more detailed computational analysis is performed. did. The shape of the coal stockpile pile was 15m high and 40m wide, making it almost similar to an actual coal-fired power plant storage yard. In addition, the grain size of the coal stockpile was made relatively large at both ends of the lower part, at an average of about 30 mm, like an actual coal pile, to ensure smooth inflow of external air, and the remaining area had an average grain size of 2.2 mm or more. The range was set to 6.3mm.

As shown in Figures 4 and 5, a computerized analysis of the external conditions of the coal stockpile and the spontaneous combustion prevention effect that can be obtained by forming a grid system of the coal stockpile and then applying a spontaneous combustion inhibitor is performed. did. The main purpose of the spontaneous combustion inhibitor is to apply the spontaneous combustion inhibitor to the surface of the coal stockpile to block the coal from contacting the outside air, that is, oxygen. Therefore, the conditions for applying the spontaneous combustion inhibitor to perform computerized analysis were established. A wall boundary condition (ranging from 0 to 40% based on the floor) was specified in the coal stockpile grid system to prevent air penetration.

Here, the wall boundary condition means the height from 0 to 40% of the floor when the height from the bottom of the coal stockpile to the top is 100%.

In this way, the difference in temperature change after a period of about 30 days was compared between the case where the spontaneous combustion inhibitor was applied and the case where the spontaneous combustion inhibitor was not applied to the coal stockpile under the same conditions, and the results are shown in Figure 6. It was.

Figure 6a is a view without the autoignition preventer applied, and Figure 6b is a view with the autoignition preventer applied.

As shown in Figure 6a, when a spontaneous combustion inhibitor was not applied, the temperature rose at both ends of the lower end of the stockpile with large coal particles, almost similar to the spontaneous combustion phenomenon that occurs in an actual coal-fired power plant storage facility.

On the other hand, when the spontaneous combustion inhibitor was applied as shown in Figure 6b, the temperature at the initial stage of combustion was maintained even though the same amount of time had elapsed, and the temperature of the relevant area did not increase further. Although the temperature rose slightly above the 40% position where wall boundary conditions were not formed, the temperature at which spontaneous ignition occurs was not reached due to the relatively small size of the coal particles. As a result, a spontaneous ignition preventer was applied to the surface of the coal stockpile to ignite the coal. It was found that the effect of preventing spontaneous combustion was very large when contact with the outside air was fundamentally blocked.

Experimental Example 3. Spontaneous combustion simulation experiment

Experimental Example 3 evaluated oxygen concentration and temperature changes by coal pile depth in an outdoor spontaneous combustion simulation device.

In the case of an outdoor spontaneous combustion simulation device, as shown in Figure 7, in a similar form to the coal storage of a 500 MW standard coal-fired power plant, 200 kg of raw coal with a particle size of 50 mm was piled up for the experiment, and the degree of heat accumulation and ignition inside the coal according to atmospheric temperature and humidity was measured. It is configured for monitoring. In particular, since the spontaneous ignition phenomenon mostly occurs in the 1m to 2m range of the surface layer of the coal pile, which is easily in contact with external air and moisture, the spontaneous ignition simulator was also designed to measure the temperature change at the upper part.

The spontaneous combustion inhibitor is made by mixing 60% coal ash containing 29% CaO based on 100% weight, 5.25% ethylene resin liquid additive, and 34.75% water at an ultrasonic wave frequency of 150 kHz, irradiation time of 10 minutes, and a stirring speed of 250 rpm. The results of a simulation test of spontaneous ignition of a coal pile coated with an anti-spontaneous ignition agent and monitoring of oxygen concentration and temperature changes at each depth of the coal pile are shown in Figures 8 to 11.

Figure 8 is the result of monitoring the oxygen concentration inside the coal pile at a depth of 50 cm, and Figure 9 is the result of monitoring the oxygen concentration inside the coal pile at a depth of 1 m. As shown, when the spontaneous combustion inhibitor was applied, the oxygen concentration was monitored for 2 weeks (14 days). ), it was confirmed that the oxygen concentration inside the coal pile decreased rapidly.

Figure 10 is the result of monitoring the internal temperature of the coal pile at a depth of 50 cm, and Figure 11 is the result of monitoring the internal temperature of the coal pile at a depth of 1 m. As shown, the internal temperature at a depth of 50 cm increases or decreases in proportion to the air temperature. When no ignition inhibitor was applied, the temperature rose rapidly after 25 days, indicating ignition initiation.

Experimental Example 4. Field application evaluation of spontaneous combustion inhibitors for coal

Experimental Example 4 was conducted to demonstrate the effect of reducing spontaneous combustion in a coal storage site by applying the spontaneous combustion inhibitor for coal of the present invention to a coal storage site at a coal-fired power plant. It was applied to an outdoor coal storage site at the Taean Thermal Power Plant of Korea Western Power Plant and was carried out in the same order as shown in Figure 12. A field verification process was conducted. At this time, spontaneous combustion inhibitors for coal were classified into one type when coal ash containing 29% by weight of calcium oxide (CaO) was added, and two types of spontaneous combustion inhibitors when coal ash containing 5% by weight of calcium oxide (CaO) was added. . The mixing conditions were 60% by weight of coal ash, 5.25% by weight of ethylene resin liquid additive, and 34.75% by weight of water, and mixed at an ultrasonic wave frequency of 150kHz, irradiation time of 10 minutes, and a stirring speed of 250rpm.

As shown in Figure 13, after unloading 5,000 tons of SM low-grade coal, which frequently spontaneously ignites, each coal pile slope (50) was placed at 30 points at intervals of 3 m in height and 3 m in width, 30 cm, 50 cm, 100 cm, and 150 cm deep from the slope surface. A total of 120 contact temperature sensors (51) were installed each. The contact temperature sensor 51 is configured to measure temperatures below 400°C in real time at 0.1°C intervals, and measures 30cm, 50cm, and 100cm at slope distances of 1.5m, 3.0m, 6.0m, 9.0m, and 12m from the floor. And temperature sensors were installed at each depth of 150 cm to measure temperature changes.

In addition, the contact-type temperature sensor 51 formed on the coal pile slope 50 is divided by depth as shown in FIG. 14, and the first temperature sensor 51-1, which is a 30 cm temperature sensor based on the coal pile slope surface, is based on the coal pile slope surface. The second temperature sensor (51-2) is a 50cm temperature sensor, the third temperature sensor (51-3) is a 100cm temperature sensor based on the surface of the coal pile slope, and the fourth temperature sensor (51-4) is a 150cm temperature sensor based on the surface of the coal pile slope. ) were installed at 1.5m, 3.0m, 6.0m, 9.0m, and 12m from the floor, depending on the height of the slope and at 3m widths on the left and right. After installation of the temperature sensor, the temperature sensor was installed at 1 minute intervals for 30 days, depending on the location depending on whether or not the fire retardant was applied. Temperature changes were measured.

As shown in FIG. 13, the area where one type of spontaneous combustion inhibitor for coal was applied was classified as G4, the area where two types of spontaneous combustion inhibitor for coal were applied was classified as F4, and one type of spontaneous combustion inhibitor for coal and the spontaneous combustion inhibitor were classified as F4. Temperature sensors at a depth of 1m where two types were applied were classified as G4-1 and F4-1, respectively, and temperature sensors at the same slope height and depth where no spontaneous combustion inhibitor for coal was applied were classified as G6-1 and F6-1, respectively. It was divided into:

Figure 15 is a graph showing the results of temperature increase at a depth of 1 m inside depending on whether or not a spontaneous combustion inhibitor for coal is applied.

As shown in Figure 15, after one day, the air temperature shows changes depending on the day and night, and the point G4-1 and F4-1 where the spontaneous combustion inhibitor for coal is applied has a low constant temperature increase gradient, so spontaneous combustion is unlikely to occur. On the other hand, at points G6-1 and F6-1 where the spontaneous combustion inhibitor for coal was not applied, the temperature increased rapidly after 36 days, and spontaneous combustion was found to occur.

Figures 16 and 17 show the surface condition of the spontaneous combustion inhibitor for coal and the removal of the TC (thermocouple) support matrix after completing the 30-day demonstration period.

As shown in Figure 16, the durability of the spontaneous combustion inhibitor for coal of the present invention remains solid even after 41 days, and as shown in Figure 17, the durability of the surrounding surface was confirmed to be excellent except for the removal point of the TC (thermocouple) support matrix. It has been done.

As seen above, the production system for the spontaneous combustion inhibitor for coal according to the present invention and the subsequent irradiation of ultrasonic waves while stirring the raw materials for the spontaneous combustion inhibitor for coal have the effect of delaying the curing speed of the spontaneous combustion inhibitor for coal so that it is sprayed smoothly. There is.

When applying the spontaneous combustion inhibitor for coal of the present invention to a pile of coal, it is not applied to the entire surface, but is applied around the area where spontaneous combustion frequently occurs, thereby effectively preventing spontaneous combustion by using a relatively small amount of spontaneous combustion inhibitor. can do.

In addition, spontaneous combustion inhibitors for coal recycle landfill wastes such as high-carbon coal ash, high-calcium coal ash, household waste incineration ash, blast furnace slag, or soot ash as main raw materials, and use ethylene-based resin additives as raw materials to prevent spontaneous combustion of low-grade coal from low-grade coal. In order to prevent spontaneous combustion, the calcium component ultimately reduces the amount of sulfur oxides (SO ₂ ) generated as a desulfurization agent in the furnace through boiler recombustion, and the unburned carbon component reinforces heat through combustion and is then recycled by being generated as coal ash, so it is used by the government. It is expected to contribute to the recycling of power generation by-products from coal-fired power plants and the realization of an eco-friendly power industry that can respond to power plant safety issues by responding to resource recycling policies and preventing spontaneous combustion.

In addition, even when a large amount of hydrophilic coal ash is added through ultrasonic irradiation and an ethylene-based resin liquid additive, which is a hardener, is mixed with water, the water molecules are decomposed into OH radicals and hydrogen radicals, thereby increasing the diffusion and penetration characteristics of ordinary hardener solutions. By delaying the bonding speed between molecules, it has excellent technical and economical features in that it can delay the curing speed and improve smooth spraying during the mixing manufacturing process.

1: Water storage tank 2: Control valve of water storage tank
3: Asphalt solution storage tank 4: Control valve of asphalt storage tank
5: EVA storage tank 6: Control valve of EVA storage tank
7: Nitrate urea storage tank 8: Control valve of nitric acid urea storage tank
9: Cellulose storage tank 10: Control valve of cellulose storage tank
11: Ethylene-based resin liquid additive mixing tank
12: Control valve of ethylene resin liquid additive mixing tank
13: solid raw material storage tank 14: solid raw material transport control screw valve
15: Ca(OH) ₂ storage tank 16: Ca(OH) ₂ transfer control screw valve
17: Liquid raw material supply unit 18: Solid raw material supply unit
20: raw material storage unit 21: rotation motor
22: ultrasonic generator 23: insulation part
25: rotation axis 26: outlet
27: mixing tank 30: manufacturing department
31: discharge line 32: injection pump
33: Spontaneous combustion preventer control valve 34: Spray line
35: spray nozzle 40: spray unit
50: Coal pile slope 51: Contact temperature sensor
51-1: first temperature sensor 51-2: second temperature sensor
51-3: Third temperature sensor 51-4: First temperature sensor

Claims (13)

Raw material storage unit for spontaneous combustion inhibitors for coal;
a mixing tank forming a space therein to accommodate the raw materials supplied from the raw material storage unit;
A stirrer located at the inner center of the mixing tank and rotating to mix the raw materials; and
An ultrasonic generator connected to the mixing tank to irradiate ultrasonic waves to the raw materials. According to paragraph 1,
The mixing tank is,
an inlet through which raw materials delivered from the raw material storage unit flow; and
A system for manufacturing a spontaneous combustion inhibitor for coal, comprising: an outlet through which the spontaneous combustion inhibitor for coal manufactured from the mixing tank is discharged. According to paragraph 1,
The raw material storage unit,
A solid raw material storage tank storing one or more selected from coal ash, incineration ash, and slag;
An ethylene-based resin liquid additive storage tank storing one or more selected from ethylene vinyl acetate, asphalt, urea nitrate, and cellulose; and
A system for producing a spontaneous combustion inhibitor for coal, comprising a water storage tank. According to paragraph 1,
The stirrer,
A rotating shaft provided at the inner center of the mixing tank to transmit rotational power; and
Manufacture of a spontaneous combustion inhibitor for coal, comprising: a plurality of rotating blades provided on the rotating shaft to receive rotational power from the rotating shaft and rotate to mix the raw materials, and a plurality of rotating blades are formed symmetrically with respect to the rotating shaft; system. According to paragraph 1,
A discharge line through which the spontaneous combustion inhibitor for coal manufactured in the mixing tank is discharged; and
A spraying unit connected to one end of the discharge line to inject the spontaneous combustion inhibitor for coal onto the target coal through a spray nozzle. (a) Injecting water and an ethylene-based resin liquid additive as liquid raw materials into the mixing tank;
(b) introducing a solid raw material containing at least one selected from coal ash, incineration ash, and slag into the mixing tank;
(c) irradiating ultrasonic waves to the raw materials introduced into the mixing tank and simultaneously stirring them. According to clause 6,
In step (c),
A method for producing a spontaneous combustion inhibitor for coal, characterized in that the raw material is irradiated with an ultrasonic frequency of 150 to 300 kHz for 10 to 20 minutes. According to clause 6,
In step (c),
A method for producing a spontaneous combustion inhibitor for coal, characterized in that the raw materials are stirred at 200 rpm to 300 rpm. According to clause 6,
After step (c) above,
A method for manufacturing a spontaneous combustion inhibitor for coal, comprising a spraying step of spraying the prepared spontaneous combustion inhibitor for coal onto a target coal pile using a spray nozzle. Solid raw materials containing at least one selected from coal ash, incineration ash, and slag;
Ethylene resin liquid additive; and
A spontaneous combustion inhibitor for coal, characterized in that it contains water. According to clause 10,
Regarding 100% by weight of the total spontaneous combustion inhibitor for coal,
The solid raw material is 55% by weight to 65% by weight;
The ethylene-based resin liquid additive is 4.5% by weight to 6.5% by weight;
The spontaneous combustion inhibitor for coal, characterized in that the water is 30.5% by weight to 40.5% by weight. In paragraph 10
With respect to 100% by weight of the solid raw material,
15% to 40% by weight of calcium oxide; and
A spontaneous combustion inhibitor for coal comprising 5% to 25% by weight of unburned carbon. According to clause 10,
With respect to 100% by weight of the ethylene resin liquid additive,
20% to 30% by weight of ethylene vinyl acetate;
Asphalt 60% to 70% by weight;
Urea nitrate 0.002% to 2% by weight;
A spontaneous combustion inhibitor for coal comprising 5% to 20% by weight of cellulose.