Effective use method of waste plastic crushed product

Abstract

To provide an effective use method of a waste plastic crushed product, when operating a boiler given a situation where a fuel is produced by combining coal and a waste plastic crushed product, the method capable of efficiently combusting in the boiler and efficiently performing various processing (flue gas denitrification processing, dust collection processing, and flue gas desulfurization processing).SOLUTION: The disclosed method includes the steps of: subjecting coal to fine particle processing by a vertical mill (14) to obtain powdered coal; granulating a waste plastic crushed product by a crusher (18) to obtain a crushed product; mixing the powdered coal and the crushed product to obtain a mixed fuel; and generating power to rotate a turbine (40) connected to the boiler by loading the mixed fuel into the boiler (20) and operating the boiler.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for effectively utilizing waste plug rush products, which enables efficient combustion in the combustion systems of various plants and also enables efficient exhaust gas treatment (flue gas denitrification treatment, dust collection treatment, flue gas desulfurization treatment, etc.) in the exhaust systems of the plants. [Background technology]

[0002] BACKGROUND ART It has been disclosed in the past that combustible solid resins such as plastics are used as fuel in cement manufacturing kilns (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-256277 Summary of the Invention [Problem to be solved by the invention]

[0004] Efforts to recycle plastic products have been strengthened under the Act on Promotion of Resource Recycling of Plastics, which came into effect in April 2022. However, when discarded plastic products are recycled, typically 30% to 45% of them become waste plastic waste (defective products generated during the material recycling process). Although these waste plastic waste products are combustible, they are currently treated as industrial waste and are disposed of by recycling companies, who incur high disposal costs.

[0005] For example, there are cases where waste plug rush products are used as supplementary fuel for rotary kilns in cement factories or fluidized bed boilers. In both of these cases, the recycling companies often bear the cost of processing the waste plug rush products, and the cost of processing the waste plug rush products is a hindrance to the stability of the recycling companies' business.

[0006] Under these circumstances, instead of using plastics and other combustible solid resins (especially waste plug rush products) in the cement plants and other places mentioned above, consideration is being given to using them as fuel for the pulverized coal-fired boilers that are in operation throughout Japan. In particular, if waste plug rush products are used as fuel for pulverized coal-fired boilers, not only will they be valuable and saleable, but they could also serve as a substitute for coal, most of which is imported from overseas.

[0007] However, because expensive coal is typically used as fuel in boilers, if most of the coal is replaced with inexpensive waste plug rush, the waste plug rush may not burn well, and various emitted gases may not meet specified environmental standards.

[0008] For this reason, consideration has been given to operating boilers by replacing some of the coal with waste plug rush products. However, if coal and waste plug rush products are fed into a boiler separately and combusted, a desirable flame cannot be obtained, and there is a risk that combustion will not occur efficiently within the boiler.

[0009] Furthermore, when coal and waste plug rush products are fed into a boiler separately and burned, the concentration of exhaust gas components emitted from the boiler may change over time, which may complicate various processes (flue gas denitrification process, dust collection process, and flue gas desulfurization process) in the plant's exhaust system.

[0010] The present invention has been made in view of the above circumstances, and aims to provide a method for effectively utilizing waste plug rush products, which is based on the premise that coal and waste plug rush products are combined to be used as fuel, and which, when a boiler is operated, produces a suitable flame within the boiler, thereby enabling efficient combustion within the boiler and enabling various processes (flue gas denitrification, dust collection, and flue gas desulfurization) to be carried out efficiently. [Means for solving the problem]

[0011] The method for effectively utilizing waste plug rush of the present invention is characterized by comprising the steps of: pulverizing coal in a vertical mill to obtain pulverized coal; reducing the waste plug rush in a crusher to obtain pulverized glass; mixing the pulverized coal and the pulverized glass to obtain a mixed fuel; and generating electricity by feeding the mixed fuel into a boiler and operating the boiler to rotate a turbine connected to the boiler. [Effects of the Invention]

[0012] In the method for effectively utilizing waste plug rush according to the present invention, the pulverized coal and the pulverized glass product are not fed separately into the boiler, but are first pulverized and crushed to the maximum particle size optimal for combustion, then mixed together, and then fed into the boiler. This allows the boiler to be operated with the pulverized coal and the pulverized glass product suitably mixed. This allows for a suitable flame to be obtained in the boiler, which in turn allows for efficient combustion in the boiler, and also suppresses changes over time in the concentrations of each exhaust gas component, allowing for efficient performance of various processes (flue gas denitrification, dust collection, and flue gas desulfurization). [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a block diagram showing each step of the method for effectively utilizing waste plug rush products according to this embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the entire plant for carrying out the steps shown in FIG. [Figure 3] FIG. 3 is a schematic diagram showing an example of the crusher (cutting-type crusher) shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] <Basic form> The basic form of the effective utilization method for waste plug rush products will be described in detail below. 1 is a block diagram showing the steps of the method for effectively utilizing waste plug rush according to the present embodiment. As shown in the figure, the method for effectively utilizing waste plug rush according to the present embodiment includes a step of obtaining pulverized coal (step 1), a step of obtaining pulverized grinding product (step 2), a step of obtaining a mixed fuel of the pulverized coal and the pulverized grinding product (step 3), and a power generation step of feeding the mixed fuel into a boiler to rotate a turbine (step 4).

[0015] Fig. 2 is a schematic diagram showing the entire plant for carrying out the steps shown in Fig. 1. The plant 10 shown in Fig. 2 is roughly divided into a fuel mixing system A, a combustion system B, an exhaust system C, and a power generation system D, which are surrounded by dotted lines.

[0016] 1 are carried out in the fuel mixing system A, and step 4 shown in Fig. 1 is carried out in the combustion system B, exhaust system C, and power generation system D. Each of steps 1 to 4 will be described in detail below.

[0017] [Process 1] Process 1 is a process for obtaining pulverized coal. In this process, coal to be used as fuel is charged into a coal bunker 12 shown in Fig. 2 (mixing system A of plant 10), and then this coal is charged through a pipe P1 into a vertical mill 14, where it is crushed until the maximum particle size becomes equal to or smaller than a predetermined value.

[0018] Here, the vertical mill 14 refers to a type of mill in which compressive and shear forces act on the coal directly below the rollers. By using the vertical mill 14, it is possible to simultaneously crush, dry, and classify the coal, thereby obtaining pulverized coal within a predetermined maximum particle size range.

[0019] The maximum particle size of the pulverized coal is set to 70 μm or more and 90 μm or less so that it can be mixed and burned well with the pulverized grash product described later. Here, the maximum particle size of the pulverized coal refers to the maximum dimension between two points on the surface of the pulverized coal.

[0020] [Process 2] Process 2 is a process for obtaining crushed and crushed plastic products, and this process is carried out simultaneously with the above-mentioned process 1. In process 2, crushed waste plastic products to be used as fuel are fed into a waste plastic bunker 16 shown in Fig. 2 (mixing system A of plant 10), and then this crushed waste plastic products are fed into a crusher 18 through a pipe P2, where they are crushed until the maximum particle size is equal to or smaller than a predetermined value.

[0021] Fig. 3 is a schematic diagram showing an example (cutting-type crusher 181) of the crusher 18 shown in Fig. 2. The cutting-type crusher 181 shown in Fig. 3 includes an input chute 181a for inputting the waste plug rush products WP1, which are fuel, a cutter 181b that rotates at a constant speed to crush the waste plug rush products WP1, and a screen mesh 181c for classifying the crushed fuel and separating crushed glass products WP2 crushed to a predetermined particle size or smaller from the other fuel.

[0022] The input chute 181a is not particularly limited and may have any known configuration. For example, as shown in Fig. 3, the input chute 181a may be configured to input the waste plug rush products WP1 diagonally downward (in the direction of the arrow) from the supply port S, or, although not shown, may be configured to input the waste plug rush products vertically downward from the supply port.

[0023] The cutter 181b has at least one blade that rotates at a constant speed (for example, in the direction of the arrow) to crush the waste plug rush products WP1. By configuring the cutter 181b with three or more blades (as shown in FIG. 3), the waste plug rush products WP1 can be crushed efficiently.

[0024] The screen mesh 181c is disposed vertically below the center of rotation of the cutter 181b and at a position where it does not come into contact with the cutter 181b during rotation, and has a mesh shape that allows the pulverized grinding product WP2, which has been crushed to a maximum particle size of a predetermined value or less, to be separated from the remaining fuel that has not been crushed sufficiently and to be deposited on the floor vertically below the screen mesh 181c. Any known shape can be used for the mesh shape, but a regular polygon or a circle is preferable so that the pulverized grinding product WP2 can be suitably mixed with the pulverized coal in the mixing step described below.

[0025] By rotating the cutter 181b using the cutting-type crusher 181 configured as described above, the waste plug rush product WP1 is pinched between the inner wall of the cutting-type crusher 181 and the cutter 181b and crushed one after another to become crushed grind product WP2 of a predetermined particle size or less.The crushed grind product WP2 then passes through the screen mesh 181c and falls, and is deposited on the floor of the cutting-type crusher 181.

[0026] The maximum particle size of the ground glass product WP2 can be set to 1000 μm or more and 3000 μm or less so that it can be well mixed with the ground glass product described above. Here, the maximum particle size of the ground glass product WP2 refers to the maximum dimension between two points on the surface of the ground glass product WP2.

[0027] [Process 3] Step 3 is a step of obtaining a mixed fuel of pulverized coal and pulverized glass product WP2. In this step, a mixer such as a mixer can be used, but in the example shown in Figure 3, pulverized coal and pulverized glass product WP are mixed without using a mixer, as described below.

[0028] The pulverized coal obtained in step 1 travels from the vertical mill 14 in Fig. 2 through pipe P3 in the direction of the arrow, and the pulverized glass product WP2 obtained in step 2 travels from the crusher 18 in Fig. 2 through pipe P4 in the direction of the arrow. Next, the pulverized coal and the pulverized glass product WP2 each travel to a connecting point CP between pipes P3 and P4, and then travel from connecting point CP through pipe P5 in the direction of the arrow.

[0029] Air is sent into the pipes P3 to P5 in the direction of the arrows, and this air generates turbulence near the connecting part CP, which allows the pulverized coal and the pulverized grinding product WP2 to mix well. In this way, these fuel components (pulverized coal and pulverized grinding product WP2) move toward the boiler 20 of the combustion system B while being well mixed in the pipe P5.

[0030] The mixing ratio of pulverized coal to pulverized glass product WP2 in the connecting portion CP can be in the range of 95:5 to 80:20 by weight. If the proportion of pulverized coal in this mixing ratio is less than 80% (i.e., if the proportion of pulverized glass product WP is more than 20%), a large amount of undesirable exhaust gas will be generated, as described below, which is undesirable. On the other hand, if the proportion of pulverized coal in this mixing ratio is more than 95% (i.e., if the proportion of pulverized glass product WP is less than 5%), the merit (economic merit) of substituting waste pulverized glass product for part of the coal will not be fully obtained, which is undesirable.

[0031] From this viewpoint, the mixing ratio of the pulverized coal to the pulverized glass product WP2 in the connecting portion CP is more preferably in the range of 93:7 to 83:17 by weight, and even more preferably in the range of 90:10 to 85:15.

[0032] [Step 4] Process 4 is a power generation process in which a mixed fuel consisting of pulverized coal and pulverized grash is fed into a boiler to operate the boiler and rotate a turbine connected to the boiler. In this process, as shown in Figure 2, the combustion system B, exhaust system C, and power generation system D of the plant 10 are operated in sequence. In this process, a pulverized coal-fired boiler is used as the boiler 20.

[0033] In step 3, the mixed fuel (consisting of pulverized coal and pulverized grinding products) that has been transported through pipe P5 in the direction of the arrow is fed into boiler 20. At this time, the mixed fuel is burned under conditions in which moisture (not shown) is supplied from the outside, and exhaust gas and steam are generated inside boiler 20.

[0034] The exhaust gas moves in the direction of arrow X within the boiler 20, passes through a pipe P6, and is input into an exhaust system C, which will be described later. On the other hand, the steam moves in the direction of arrow Y within the boiler 20, passes through a pipe P7, and is input into a power generation system D, which will be described later.

[0035] In the exhaust system C, the exhaust gas EG passes through the flue gas denitration device 30, pipe P8, air preheater 32, pipe P9, dust collector 34, pipe P10, flue gas desulfurization device 36, pipe P11, and exhaust stack 38 in that order, before being released into the outside air. Note that known devices or equipment can be used for the flue gas denitration device 30, air preheater 32, dust collector 34, flue gas desulfurization device 36, and exhaust stack 38.

[0036] In the power generation system D, steam travels through pipe P7 in the direction of the arrow and is injected into the turbine 40, where it serves as a power source for the turbine 40 to generate electricity and supply electric power EP to the outside. Note that a known device can also be used for the turbine 40.

[0037] (Principle, effects, etc. of this embodiment) Conventionally, it has been practiced to combine pulverized coal (pulverized coal) and pulverized glass (pulverized waste plug-in glass) as fuel to operate a boiler to generate steam, which is then used to operate a turbine to generate electricity. However, in the conventional combustion system, the pulverized coal and the pulverized glass were introduced separately into the boiler, which meant that there was a risk that combustion would occur before the pulverized coal and the pulverized glass were sufficiently mixed. As a result, the flame generated in the boiler had unevenness in the degree of combustion (local variations in color intensity), even when judged visually.

[0038] Such variations in the degree of combustion in the flames generated inside the boiler are undesirable from the standpoint of combustion efficiency, and this results in a relatively high reject rate (the percentage of waste plug rush products that are not effectively used as fuel) when converting waste plug rush products into fuel.

[0039] Furthermore, if combustion is carried out before the pulverized coal and pulverized glass product are sufficiently mixed, there is a risk that the concentrations of components (e.g., NO2, SO2, and CO) in the exhaust gas emitted from the boiler will change over time when the boiler is operated for a predetermined time (e.g., 12 hours). In such a case, various treatments (flue gas denitrification treatment, dust collection treatment, and flue gas desulfurization treatment) must be considered, taking into account not only the maximum emission amount per predetermined time for each component of the exhaust gas, but also the minimum emission amount per predetermined time, and as a result, there is a risk that these treatments cannot be carried out efficiently.

[0040] Incidentally, when a boiler is operated using only pulverized coal as fuel, visual observation of the flame generated inside the boiler reveals that there is not much variation in the color of the flame, which means that efficient combustion is taking place.

[0041] Similarly, when only pulverized coal is fed into a boiler as fuel and the boiler is operated for a predetermined time (for example, 12 hours), the change over time in the concentrations of exhaust gas components (for example, NOx, SOx, and CO) is extremely small. In such cases, it is sufficient to consider various treatments (flue gas denitrification treatment, dust collection treatment, and flue gas desulfurization treatment) assuming only the average emission amount of each exhaust gas component, and as a result, these treatments can be carried out efficiently.

[0042] Based on the above findings, the present inventors have conducted extensive research into an effective utilization method for waste plug rush materials, which would ensure that even when a boiler is operated using a combination of pulverized coal and pulverized glass products as fuel, the color intensity of the flame remains the same as when the boiler is operated using only pulverized coal as fuel, thereby achieving efficient combustion.The present inventors have also conducted extensive research into an effective utilization method for waste plug rush materials, which would ensure that even when a boiler is operated using a combination of pulverized coal and pulverized glass products as fuel, the concentration of components in the exhaust gas emitted from the boiler changes over time to the same extent as when the boiler is operated using only pulverized coal as fuel, thereby enabling various processes (flue gas denitrification, dust collection, and flue gas desulfurization) to be carried out efficiently.

[0043] As a result, the inventor discovered that by combining pulverized coal and pulverized ground coal and thoroughly mixing them before feeding them into a boiler as fuel, the color of the flame generated in the boiler would not show much variation in color, and efficient combustion would be achieved.

[0044] The inventors have also discovered that by thoroughly mixing pulverized coal and pulverized ground powder before feeding them into a boiler as fuel, it is possible to control the change in concentration over time of the exhaust gas components emitted from the boiler to the same extent as when the boiler is operated using only pulverized coal as fuel, thereby making it possible to efficiently carry out various processes (flue gas denitrification process, dust collection process, and flue gas desulfurization process).

[0045] As described above, the method for effectively utilizing waste plug rush of this embodiment is characterized by thoroughly mixing the pulverized coal and the pulverized plug rush before feeding them into a boiler as fuel.

[0046] As shown in the example of Figure 2, the pulverized coal and the pulverized grinding product are mixed at the connection point CP between the pipe P3 through which the pulverized coal moves and the pipe P4 through which the pulverized grinding product moves, and then these fuel components (pulverized coal and pulverized grinding product) are mixed in the pipe P5 through which they continue to move to the boiler 20.

[0047] When mixing two types of fuel components in this manner, by making the air flow turbulent, particularly near the connecting portion CP, the mixing of these fuel components can be carried out in a narrow area within the pipe, and as a result, the dimensions of the pipe P5 can be made relatively short.

[0048] To generate such turbulence, it is preferable to relatively control the air flow in pipe P2 and the air flow in pipe P4, and it is even more preferable to relatively control the air flow in three pipes, including pipe P5 in addition to pipes P2 and P4.

[0049] The above-described method for effectively utilizing waste plug rush products not only reduces the variation in color of the flame generated in the boiler, thereby enabling efficient combustion, but also keeps the change in concentration of exhaust gas components emitted from the boiler over time to the same level as when the boiler is operated using only pulverized coal as fuel, thereby enabling various processes (flue gas denitrification, dust collection, and flue gas desulfurization) to be carried out efficiently.

[0050] <Preferred form> In the basic configuration described above, the inventors have conducted extensive research into an effective utilization method for waste pump gun waste, which can achieve more efficient combustion by further reducing the shading of the color of the flame generated in the boiler and can also make the change in concentration of exhaust gas components over time very similar to that of a boiler operated using only pulverized coal as fuel, thereby enabling more efficient processing (flue gas denitrification, dust collection, and flue gas desulfurization). More specifically, the inventors selected various combinations of maximum particle sizes for the pulverized pump gun waste before mixing and the pulverized coal, and investigated which of these combinations has a positive effect on the color of the flame and the change in concentration of exhaust gas components over time.

[0051] As a result, it was found that by setting the maximum particle size of the pulverized glass product to between 1000 μm and 3000 μm and the maximum particle size of the pulverized coal to between 70 μm and 90 μm, the color variation in the flame generated in the boiler can be further reduced, resulting in more efficient combustion.In addition, it was found that by adopting a combination of the maximum particle size of the pulverized glass product and the maximum particle size of the pulverized coal within the above ranges, the change in concentration over time of the exhaust gas components emitted from the boiler can be made to closely resemble that when the boiler is operated using only pulverized coal as fuel, resulting in more efficient various processes (flue gas denitrification, dust collection, and flue gas desulfurization).

[0052] The physicochemical reasons why such favorable results are obtained with respect to the above ranges of the maximum particle size of the pulverized glass product and the maximum particle size of the pulverized coal are unclear, but the present inventors have found that it is more preferable to set the maximum particle size of the pulverized glass product to 1200 μm or more and 2800 μm or less and the maximum particle size of the pulverized coal to 72 μm or more and 78 μm or less, and it is extremely preferable to set the maximum particle size of the pulverized glass product to 1500 μm or more and 2500 μm or less and the maximum particle size of the pulverized coal to 73 μm or more and 77 μm or less. [Example]

[0053] (Example 1: Verification of flame color due to differences in fuel mixing conditions) In Example 1, the plant 10 shown in FIG. 2 was used to investigate the following invention example 1 and comparative example.

[0054] In Example 1, waste plastic rush was fed into the waste plastic bunker 16, and coal was fed into the coal bunker 12 to operate the boiler 20, thereby obtaining a mixed fuel (composed of pulverized coal and pulverized grinding product). The mixed fuel was then fed into the boiler 20 to operate the boiler 20, which rotated the turbine 40 connected to the boiler 20 to generate electricity (waste plastic mixed combustion). The maximum particle size of the pulverized coal was approximately 2000 μm or less, the maximum particle size of the pulverized grinding product was 75 μm or less, and the mixing ratio of the pulverized coal to the pulverized grinding product was 90:10 by weight.

[0055] In contrast, in the comparative example, instead of feeding waste plastic rush products into the waste plastic bunker 16, coal was fed into the coal bunker 12 and the boiler 20 was operated to rotate the turbine 40 connected to the boiler 20 to generate electricity (single-fired coal).The maximum particle size of the pulverized coal was set to 70 μm or more and 80 μm or less.

[0056] According to the inventors, even when a mixed fuel of pulverized coal and pulverized grash is used, if these fuel components are mixed before feeding the fuel into the boiler (Invention Example 1), a good flame color is obtained, equivalent to when only pulverized coal is used (Comparative Example), and it has been found that this enables efficient combustion.

[0057] (Example 2: Verification of exhaust gas component concentrations due to differences in fuel blending patterns) In Example 2, the plant 10 shown in FIG. 2 was used to investigate the following invention examples 2 to 4.

[0058] Using the plant 10 shown in Figure 2, from exactly 12:00, without putting waste plastic rush products into the waste plastic bunker 16, coal was put into the coal bunker 12 and the boiler 20 was operated, rotating the turbine 40 connected to the boiler 20 to generate electricity for six hours, until exactly 18:00 (single-fired coal). The maximum particle size of the pulverized coal was set to 2000 μm, between 70 μm and 90 μm.

[0059] After that, starting at exactly 6:00 PM, waste plastic rush was put into the waste plastic bunker 16, and coal was put into the coal bunker 12 to operate the boiler 20, thereby obtaining a mixed fuel (consisting of pulverized coal and pulverized grinding product). The mixed fuel was then put into the boiler 20, which was then operated to rotate the turbine 40 connected to the boiler 20 and generate electricity for six hours (waste plastic mixed combustion). The maximum particle size of the pulverized coal was set to between 70 μm and 90 μm, but not more than 2000 μm, and the maximum particle size of the pulverized grinding product was set to 2000 μm or less. Furthermore, the mixing ratio of the pulverized coal to the pulverized grinding product was set to 90:10 by weight.

[0060] During this series of 12-hour power generation, the change in the NOx concentration in the exhaust gas (concentration as it passes through pipe P6 in plant 10 in Figure 2) was measured in Example 2 of the invention, the change in the CO concentration in the exhaust gas (concentration as it passes through pipe P6 in plant 10 in Figure 2) was measured in Example 3 of the invention, and the change in the SO2 concentration in the exhaust gas (concentration as it passes through pipe P6 in plant 10 in Figure 2) was measured in Example 4 of the invention.

[0061] The inventors investigated the transition of concentrations of various exhaust gases when the boiler shown in Fig. 2 was used, by operating the boiler for a certain period of time using only pulverized coal as fuel, and then continuously operating the boiler using a mixed fuel obtained by mixing pulverized coal and pulverized ground coal as fuel. Specific exhaust gas concentrations investigated were NOx concentration, CO concentration, and SO2 concentration.

[0062] These investigations revealed that for all of Examples 2 to 4, the concentrations of each exhaust gas component (NOx, CO, SO2) remained almost unchanged during 12 hours of power generation, even when switching from coal-only combustion to mixed combustion of waste plastics. These results show that even when using a mixed fuel of pulverized coal and pulverized grinding products, as long as these fuel components are mixed before being fed into the boiler, the change in concentration over time of the exhaust gas components emitted from the boiler 20 can be kept to the same level as when the boiler is operated using only pulverized coal as fuel, and as a result, various processes (flue gas denitrification, dust collection, and flue gas desulfurization) can be carried out efficiently. [Explanation of symbols]

[0063] 10 Plant 12 Coal Bunker 14 Vertical Mill 16 Waste plastic bag 18 Crusher 181 Cutting type crusher 181a Throw-in shot 181b Cutter 181c Screen mesh 20. Boiler 30 Flue gas denitrification equipment 32 Air preheater 34 Dust collector 36 Flue gas desulfurization equipment 38 Exhaust stack 40 Turbine A mixed system B Combustion system C. Exhaust system CP connection part D Power generation system EG exhaust gas EP power P1~P11 piping S supply port WP1 Waste Plug Rush Products WP2 crushed glass product

Claims

1. pulverizing the coal in a vertical mill to obtain pulverized coal; a step of crushing the waste plug rush product into small particles using a crusher to obtain a crushed plug rush product; mixing the pulverized coal with the pulverized glass product to obtain a mixed fuel; and a power generation step of rotating a turbine connected to a boiler by feeding the mixed fuel into the boiler and operating the boiler.

2. 2. The method for effectively utilizing waste brush products according to claim 1, wherein the maximum particle size of the pulverized brush product is 1000 μm or more and 3000 μm or less, and the maximum particle size of the pulverized coal is 70 μm or more and 90 μm or less.

3. 3. The method for effectively utilizing waste brush products according to claim 1, wherein the mixing ratio of the pulverized coal to the pulverized brush products is in the range of 95:5 to 80:20 by weight.

4. 3. The method for effectively utilizing waste plug rush products according to claim 1, wherein the step of obtaining the mixed fuel is carried out in a pipe connecting the vertical mill, the crusher, and the boiler.

5. 5. The method for effectively utilizing waste brush products according to claim 4, further comprising generating turbulence in a region in the pipe where the pulverized coal and the pulverized brush products join together.

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