Coal feeding device for thermal power generation

Abstract

The present application relates to the technical field of thermal power generation, and discloses a pulverized coal feeding device for thermal power generation, which comprises a columnar machine shell, a lower grinding block fixedly arranged in the columnar machine shell, an upper grinding block rotatably arranged above the lower grinding block, a guide hopper fixedly arranged below the lower grinding block, a vertical hard pipe arranged in the columnar machine shell below the discharge channel, an air outlet hole formed in the outer circumferential surface of the vertical hard pipe, a sealing sleeve connected to the lower end of the guide block and arranged on the outer circumferential surface of the vertical hard pipe as an air isolation sleeve pipe, and the air isolation sleeve pipe seals the air outlet hole; an inner ring body and an outer ring body are concentrically arranged below the air isolation sleeve pipe, and an annular rubber skin is arranged between the inner ring body and the outer ring body. The present application not only realizes very fine grinding of coal particles, but also realizes size classification of the pulverized coal after grinding by using the action of the size of the pulverized coal particles and the airflow, so that the fine pulverized coal can enter the boiler along with the airflow and be fully combusted, thereby enabling the pulverized coal entering the boiler to be fully combusted.

Description

Technical Field

[0001] This invention relates to the field of thermal power generation technology, and specifically discloses a coal pulverizer feeding device for thermal power generation. Background Technology

[0002] Thermal power generation, one of the most important power generation methods in my country, utilizes the combustion of pulverized coal in a boiler. The heat generated by the combustion of pulverized coal boils water to produce steam, which is then used to power a steam turbine. In the process of thermal power generation, the coal is crushed by a crusher, and the crushed coal particles are then fed into a coal mill for grinding into pulverized coal. The pulverized coal is then screened by a screening mechanism to ensure that only small particles of the correct size are fed into the boiler for combustion.

[0003] For example, the invention patent with application number 2018110982512 discloses a high-efficiency coal mill for thermal power generation, including a casing, a crushing chamber, a feed inlet, a first rotating cylinder, crushing teeth, a first screen, a gearbox, a grinding chamber, a second motor, a first grinding roller, a second grinding roller, a grinding roller sleeve, a drive shaft, a drive gear, a driven shaft, and a driven gear. The driven gear meshes with the drive gear. The bottom end of the driven shaft passes through the bottom of the gearbox and the top of the grinding chamber and is fixedly connected to the top of the second grinding roller. An annular material inlet is provided inside the casing on the outside of the crushing chamber. An annular discharge pipe is connected to the bottom of the annular material inlet. The bottom of the annular discharge pipe is connected to the grinding chamber. A screen plate is provided at the bottom of the grinding chamber. Several through holes are evenly opened on the screen plate. A collection box is provided below the screen plate. A second screen is provided inside the collection box. While the coal mill disclosed in this invention achieves crushing, grinding, and screening of coal, it cannot deliver the resulting coal powder into the boiler via airflow. Furthermore, the particle size of the ground coal powder is extremely small, generally needing to be controlled to around 90-160 micrometers, to ensure complete combustion in the boiler. At this size, the coal powder cannot be effectively screened using a sieve. Based on the aforementioned shortcomings of existing high-efficiency coal mills used in thermal power generation, this invention proposes a coal powder feeding device for thermal power generation. This device achieves both extremely fine grinding of the coal powder and screening of the coal powder without the use of a sieve, allowing the coal powder to automatically enter the boiler via airflow for complete combustion. Summary of the Invention

[0004] The present invention aims to provide a coal powder feeding device for thermal power generation, which can achieve extremely fine grinding of coal powder and can separate the coarse and fine coal powder by throwing and blowing the ground coal powder, so that the fine coal powder enters the boiler with the airflow for complete combustion.

[0005] This invention is achieved through the following technical solution:

[0006] A coal powder feeding device for thermal power generation includes a cylindrical casing, a feeding hopper at the upper end of the cylindrical casing, a collecting hopper at the lower end, a lower grinding block fixedly disposed in the cylindrical casing, an upper grinding block rotatably disposed above the lower grinding block, a guide hopper fixedly disposed below the lower grinding block, and a feeding channel connected to the lower end of the guide hopper.

[0007] A vertical rigid tube is concentrically arranged in the columnar housing below the feeding channel. Multiple air outlets are evenly opened at the upper end of the outer circular surface of the vertical rigid tube. The lower end is connected to an air pump located outside the columnar housing through an air supply pipe. A conical guide block is connected to the top end of the vertical rigid tube through a spring. The lower end of the guide block is connected to an air-tight sleeve that is sealed on the outer circular surface of the vertical rigid tube, and the air-tight sleeve seals the air outlets.

[0008] An inner ring and an outer ring are concentrically arranged below the air-tight sleeve. The inner ring is slidably sleeved with the vertical rigid tube, and the outer ring is fixedly connected to the cylindrical housing through a second connecting rod. An annular rubber skin is provided between the inner ring and the outer ring. An electromagnet is provided on the vertical rigid tube. An adsorption block that interacts with the electromagnet is provided at the lower end of the inner ring, and a jacking component that acts on the guide block is provided at the upper end.

[0009] A pulverized coal outlet is provided on the columnar casing located between the feed hopper and the feed block. A negative pressure ring channel communicating with the pulverized coal outlet is provided on the outer circular surface of the columnar casing. A pulverized coal airflow supply pipe connected to the boiler is provided on the negative pressure ring channel.

[0010] The coal pulverized material feeding device for thermal power generation disclosed in this invention operates by feeding crushed coal particles into the upper grinding block via a feeding hopper. The rotation of the upper grinding block then causes the coal particles to be thoroughly ground into fine powder within the grinding gaps. The ground coal powder falls into the guide hopper and is then discharged through the discharge channel. During its descent, the coal powder is dispersed in all directions by the guide block and lands on the annular rubber sheet. Simultaneously, air input by an air pump is compressed at the top of the vertical rigid pipe.

[0011] When the coal powder on the annular rubber sheet reaches a certain amount, current is passed into the electromagnet, generating magnetic attraction. Due to the magnetic attraction, the adsorption block pulls the inner ring downwards, stretching the annular rubber sheet. Then, when the current to the electromagnet is disconnected, the inner ring moves upwards instantaneously under the restoring force of the annular rubber sheet, throwing the coal powder upwards. Simultaneously, the upward movement of the inner ring lifts the guide block and the air-sealing sleeve, opening the vent. At this point, compressed air from the top of the vertical rigid pipe is discharged from the vent and blown towards the thrown coal powder. Under the action of the compressed airflow, the coal powder is blown towards the inner walls of the cylindrical casing. Fine coal powder is then drawn into the negative pressure ring channel along with the airflow and ultimately transported to the boiler via the coal powder airflow supply pipe. Larger coal powder particles fall into the collection hopper under gravity and can be directly returned by the set return auger for secondary grinding.

[0012] As a further feature of the above scheme, the upper end of the upper grinding block is a concave conical surface, the lower end of the upper grinding block is a concave conical surface, the upper end of the lower grinding block is a frustum shape that matches the lower end of the upper grinding block, and the grinding gap between the lower grinding block and the upper grinding block gradually decreases.

[0013] As a further provision of the above scheme, a tray is provided in the cylindrical housing, and a plurality of first connecting rods connected to the inner wall of the cylindrical housing are evenly arranged on the outer circular surface of the tray. The lower grinding block is fixedly installed on the upper surface of the tray.

[0014] As a further feature of the above solution, a feeding motor is provided on the tray, and a rotating shaft extending into the feeding channel is connected to the motor shaft of the feeding motor. A spiral blade located in the feeding channel is provided at the lower end of the rotating shaft.

[0015] As a further provision of the above scheme, a return auger is provided on the side of the columnar housing. The lower end of the return auger is connected to the return pipe at the lower end of the collecting hopper, and the upper end is connected to the columnar housing above the upper grinding block.

[0016] As a further feature of the above solution, the jacking assembly includes a jacking rod connected to the upper end of the inner ring body, and a pushing bar that acts on the lower surface of the guide block is connected to the top end of the jacking rod.

[0017] As a further provision of the above scheme, an annular track is provided on the inner wall of the cylindrical housing, an annular groove matching the annular track is opened on the outer circular surface of the upper grinding block, and annular teeth are also provided on the outer circular surface of the upper grinding block. A gear drive assembly that meshes with the annular teeth is provided on the cylindrical housing.

[0018] As a further feature of the above scheme, the columnar casing has multiple coal powder outlets, and the multiple coal powder outlets are arranged evenly in the circumferential direction.

[0019] As a further feature of the above scheme, a frame is also included, wherein the cylindrical housing and the return auger are both fixedly mounted on the frame.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] The coal pulverized coal feeding device disclosed in this invention not only achieves extremely fine grinding of coal particles, but also allows the ground coal to be thrown up by an annular rubber sheet and blown by high-pressure airflow during the throwing process. The coal particles are classified by size using the effect of airflow. Fine coal particles can enter the boiler with the airflow and be fully burned, while coal particles that are not ground properly are returned for secondary grinding, so that the coal particles entering the boiler can be fully burned.

[0022] This invention revolutionizes the traditional method of sieving pulverized coal. It utilizes an inner ring, an outer ring, and a ring-shaped rubber sheet as a throwing mechanism. The magnetic force of an electromagnet causes the pulverized coal on the ring-shaped rubber sheet to be thrown upwards. During this upward throwing process, the air-sealing sleeve moves upwards, opening the air outlet. Compressed air discharged from the outlet directly acts on the thrown pulverized coal, and the high-pressure airflow directly sieves the coal powder by size, eliminating the need for a sieve. Furthermore, the finer pulverized coal is directly carried into the boiler for combustion. The entire pulverized coal air-blowing sieving structure is ingeniously designed, not only achieving sieving of ground pulverized coal but also providing the effect of air-blowing pulverized coal, enabling the supply of fine pulverized coal for combustion in thermal power generation, resulting in excellent performance. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a three-dimensional structural diagram of the present invention from a first angle;

[0025] Figure 2 This is a schematic diagram of the second-angle three-dimensional structure of the present invention;

[0026] Figure 3 This is a schematic diagram of the internal three-dimensional structure of the columnar housing in this invention;

[0027] Figure 4This is a schematic diagram of the internal main view of the cylindrical housing in this invention;

[0028] Figure 5 This is a schematic diagram of the three-dimensional structure of the upper grinding block, lower grinding block, and tray in this invention;

[0029] Figure 6 This is a schematic diagram of the three-dimensional structure of the vertical rigid tube, outer ring, and annular rubber skin in this invention;

[0030] Figure 7 For the present invention Figure 4 A magnified structural diagram of point A in the middle. Detailed Implementation

[0031] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The following will refer to the appendix... Figures 1-7 This application will be described in detail with reference to the embodiments. Example 1

[0033] Example 1 discloses a coal pulverized coal feeding device for thermal power generation, as shown in the attached figure. Figure 1 and attached Figure 2 The system includes a frame 1, on which a columnar housing 2 is fixedly installed. A feeding hopper 3 is provided at the upper end of the columnar housing 2, and a collecting hopper 4 is provided at the bottom of the columnar housing 2. A return auger 5 is also fixed on the frame 1, parallel to the columnar housing 2. The upper end of the return auger 5 is connected to the upper end of the columnar housing 2, and the lower end of the return auger 5 is connected to the return pipe at the lower end of the collecting hopper 4.

[0034] Reference Appendix Figure 3 Appendix Figure 4 and attached Figure 5 An upper grinding block 6 is rotatably installed on the upper end of the inner wall of the cylindrical housing 2. The upper end of the upper grinding block 6 is designed with a downward concave conical surface, so that the coal material fed by the feeding hopper 3 or returned by the return auger can be concentrated in the through hole at the center of the upper grinding block 6. At the same time, the lower end of the upper grinding block 6 is designed with an upward concave conical surface.

[0035] A tray 7 is installed in the cylindrical casing 2 below the upper grinding block 6. Multiple radially arranged first connecting rods 8 are evenly connected to the outer circumference of the tray 7, fixing the tray 7 to the cylindrical casing 2. To prevent the ground coal powder from accumulating at the upper end of the first connecting rods 8, the cross-section of the first connecting rods 8 is designed as a sharp triangle at the top. A lower grinding block 9 is fixedly installed on the upper surface of the tray 7. The upper end of the lower grinding block 9 is designed as a frustum shape matching the lower end of the upper grinding block 6, and the grinding gap between the lower grinding block 9 and the upper grinding block 6 gradually decreases, ensuring that the coal particles are ground into extremely fine coal powder, thereby guaranteeing complete combustion of the coal powder in the boiler.

[0036] To ensure stable rotation of the upper grinding block 6 during the grinding process, an annular track is fixed to the upper end of the inner wall of the cylindrical housing 2, and a matching annular groove 601 is formed on the outer surface of the upper grinding block 6. Simultaneously, ring teeth 602 are provided on the outer surface of the upper grinding block 6, and a gearbox 10 is provided at the upper end of the outer surface of the cylindrical housing 2. A power motor 11 is mounted on the gearbox 10, and the power gear in the gearbox 10 extends through a notch on the cylindrical housing 2 to mesh with the ring teeth 602. Driven by the power motor 11 and guided by the annular track, the upper grinding block 6 rotates at a set speed above the lower grinding block 9, thereby grinding the fed coal particles.

[0037] A guide hopper 12 is fixedly connected to the inner wall of the cylindrical housing 2 below the tray 7. The guide hopper 12 is conical in shape and has a discharge channel 13 connected to its lower end. A discharge motor 14 is set at the center of the tray 7. A rotating shaft 15 extending into the discharge channel 13 is connected to the motor shaft of the discharge motor 14, and the rotating shaft 15 is concentric with the discharge channel 13. A spiral blade 16 located in the discharge channel 13 is also set at the lower end of the rotating shaft 15. The rotating shaft 15 is controlled by the discharge motor 14 to rotate at a set speed. Then, under the action of the spiral blade 16 and the discharge channel 13, the coal powder in the guide hopper 12 is fed downward in a set amount.

[0038] Reference Appendix Figure 2 and attached Figure 3 A vertical rigid pipe 17 is concentrically arranged inside the columnar casing 2 below the material feeding channel 13. An air supply pipe 18 extending out of the material collecting hopper 4 is connected to the lower end of the vertical rigid pipe 17, and an air pump 19 is connected to the outer end of the air supply pipe 18.

[0039] Reference Appendix Figure 6 and attached Figure 7Multiple air vents 171 are evenly distributed on the outer surface of the upper end of the vertical rigid pipe 17. A conical guide block 20 is provided at the top of the vertical rigid pipe 17, and the lower end of the guide block 20 is connected to the vertical rigid pipe 17 by a spring 21. When pulverized coal is discharged from the feeding channel 13, it falls onto the guide block 20, and under the action of the guide block 20, the pulverized coal can be evenly dispersed in all directions. An air-tight sleeve 22 is connected to the lower surface of the guide block 20 and is sealed to the outer surface of the upper end of the vertical rigid pipe 17, so that the air-tight sleeve 22 can seal the multiple air vents 171.

[0040] An inner ring body 23 is slidably fitted onto the outer circumference of the lower end of the vertical rigid tube 17, and an outer ring body 24 is concentrically arranged around the inner ring body 23. Multiple second connecting rods 25 are evenly connected to the outer circumference of the outer ring body 24, and the outer ends of the second connecting rods 25 are fixedly connected to the inner wall of the cylindrical housing 2. The cross-section of the second connecting rods is also triangular to prevent coal dust accumulation. A taut annular rubber sheet 26 is provided between the inner ring body 23 and the outer ring body 24, and the annular rubber sheet 26 has elastic deformation properties. An electromagnet 27 is fixedly installed on the vertical rigid tube 17 below the inner ring body 23. An adsorption block 28 interacting with the electromagnet 27 is provided at the lower end of the inner ring body 23, so that when the electromagnet 27 is energized, it can generate a magnetic attraction force on the adsorption block 28, thereby causing the inner ring body 23 to move downwards and stretching and deforming the annular rubber sheet 26. A vertically upward-facing push rod 29 is connected to the upper end of the inner ring 23, and a push bar 30 that can act on the lower surface of the guide block 20 is connected to the top of the push rod 29.

[0041] Reference Appendix Figure 1 Appendix Figure 2 and attached Figure 4 Multiple pulverized coal outlets 201 are evenly provided on the outer circular surface of the columnar casing 2 between the horizontal height of the guide hopper 12 and the guide block 20. A negative pressure ring channel 31 covering all pulverized coal outlets 201 is provided on the outer circular surface of the columnar casing 2. The negative pressure ring channel 31 is then connected to a pulverized coal air supply pipe 32 through a suction end. The pulverized coal air supply pipe 32 is connected to the furnace of the boiler through a suction pump.

[0042] In the operation of the coal powder feeding device for thermal power generation disclosed in Embodiment 1, crushed coal particles are added to the cylindrical casing 2 by the feeding hopper 3, and due to the shape design of the upper grinding block 6, the added coal particles will gather in the through hole at the center.

[0043] The power motor 11 is started, so that the power gear in the gearbox 10 meshes with the ring gear 602 on the upper grinding block 6 to make the upper grinding block 6 rotate at a constant speed. During the rotation of the upper grinding block 6, it will work together with the lower grinding block 9 to grind the coal particles that pass through the grinding gap into extremely fine powder. The coal powder after passing through the grinding gap will gather at the lower center of the guide hopper 12.

[0044] Restart the feeding motor 14 to make the shaft 15 and the spiral blade 16 rotate at the set speed. At this time, due to the interaction between the spiral blade 16 and the feeding channel 13, the coal powder will fall at a uniform speed. The falling coal powder will be scattered in all directions under the action of the guide block 20 and fall onto the annular rubber skin 26. Feeding will stop when the amount of coal powder on the annular rubber skin 26 reaches a certain amount. At the same time, during the coal powder feeding process, the drive air pump 19 is started to continuously input air into the vertical rigid pipe 17. At the same time, due to the sealing of the air-insulating sleeve 22 in the air outlet 171, the gas in the vertical rigid pipe 17 will be continuously compressed.

[0045] Next, current is passed through electromagnet 27 to generate magnetic attraction. At this time, under the action of magnetic attraction, the adsorption block 28 will drive the inner ring 23 to move downward, and cause the annular rubber skin 26 to stretch and deform. Then, the current in electromagnet 27 is cut off, the magnetic attraction disappears instantly, and under the action of the restoring force of the annular rubber skin 26, the inner ring 23 moves upward rapidly. Through the push rod 29 and the push bar 30, the guide block 20 and the air-sealing sleeve 22 are pushed upward a certain distance, so that the air outlet 171 is opened and the compressed gas in the vertical hard pipe 17 is released instantly.

[0046] At the same time, the coal powder on the annular rubber skin 26 will be instantly thrown upwards and encounter the compressed airflow. Under the action of the compressed airflow, the coal powder will be blown towards the inner wall of the cylindrical casing 2. At this time, the coal powder with smaller particle size will be sucked into the negative pressure ring channel 31 with the airflow and finally transported to the boiler along the coal powder airflow supply pipe 32. The coal powder with larger particle size will fall into the collection hopper 4 under the action of gravity, and then be fed back into the upper grinding block 6 by the return auger 5 for secondary grinding, so that the size of the coal powder after secondary grinding can meet the requirements of full combustion in the boiler.

[0047] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A coal pulverized material feeding device for thermal power generation, comprising a cylindrical casing, a feeding hopper at the upper end of the cylindrical casing, and a collecting hopper at the lower end, characterized in that, A lower grinding block is fixedly installed in the cylindrical housing, an upper grinding block is rotatably installed above the lower grinding block, a guide hopper is fixed below the lower grinding block, and a feeding channel is connected to the lower end of the guide hopper. A vertical rigid tube is concentrically arranged in the columnar housing below the feeding channel. Multiple air outlets are evenly opened at the upper end of the outer circular surface of the vertical rigid tube. The lower end is connected to an air pump located outside the columnar housing through an air supply pipe. A conical guide block is connected to the top end of the vertical rigid tube through a spring. The lower end of the guide block is connected to an air-tight sleeve that is sealed on the outer circular surface of the vertical rigid tube, and the air-tight sleeve seals the air outlets. An inner ring and an outer ring are concentrically arranged below the air-tight sleeve. The inner ring is slidably sleeved with the vertical rigid tube, and the outer ring is fixedly connected to the cylindrical housing through a second connecting rod. An annular rubber skin is provided between the inner ring and the outer ring. An electromagnet is provided on the vertical rigid tube. An adsorption block that interacts with the electromagnet is provided at the lower end of the inner ring, and a jacking component that acts on the guide block is provided at the upper end. A pulverized coal outlet is provided on the columnar casing located between the feed hopper and the feed block. A negative pressure ring channel communicating with the pulverized coal outlet is provided on the outer circular surface of the columnar casing. A pulverized coal airflow supply pipe connected to the boiler is provided on the negative pressure ring channel. As the coal dust falls, it is dispersed in all directions by the guide block and lands on the annular rubber sheet. The air input by the air pump is compressed at the top of the vertical rigid pipe, and current is passed into the electromagnet to generate magnetic attraction. The adsorption block is pulled downward by the magnetic attraction and stretches the annular rubber sheet. The current in the electromagnet is cut off. Under the action of the restoring force of the annular rubber sheet, the inner ring moves upward instantaneously, throwing the coal dust on the annular rubber sheet upward. During the upward movement of the inner ring, it will lift the guide block and the air-sealing sleeve, so that the air outlet is opened. The compressed air at the top of the vertical rigid pipe is discharged from the air outlet and blown towards the thrown coal dust. Under the action of the compressed air flow, the coal dust will be blown towards the inner wall of the cylindrical casing. The fine coal dust will be sucked into the negative pressure ring channel with the air flow.

2. The coal pulverized coal feeding device for thermal power generation according to claim 1, characterized in that, The upper end of the upper grinding block is a concave cone, the lower end of the upper grinding block is a concave cone, the upper end of the lower grinding block is a frustum shape that matches the lower end of the upper grinding block, and the grinding gap between the lower grinding block and the upper grinding block gradually decreases.

3. The coal pulverized coal feeding device for thermal power generation according to claim 1 or 2, characterized in that, A tray is provided in the cylindrical housing, and multiple first connecting rods connected to the inner wall of the cylindrical housing are evenly arranged on the outer circular surface of the tray. The lower grinding block is fixedly installed on the upper surface of the tray.

4. The coal pulverized coal feeding device for thermal power generation according to claim 3, characterized in that, The tray is equipped with a feeding motor, and the motor shaft of the feeding motor is connected to a rotating shaft that extends into the feeding channel. The lower end of the rotating shaft is equipped with a spiral blade located in the feeding channel.

5. The coal pulverized coal feeding device for thermal power generation according to claim 1, characterized in that, A return auger is provided on the side of the columnar housing. The lower end of the return auger is connected to the return pipe at the lower end of the collecting hopper, and the upper end is connected to the columnar housing above the upper grinding block.

6. The coal pulverized coal feeding device for thermal power generation according to claim 1, characterized in that, The jacking assembly includes a jacking rod connected to the upper end of the inner ring body, and a push bar that acts on the lower surface of the guide block is connected to the top of the jacking rod.

7. The coal pulverized coal feeding device for thermal power generation according to claim 1, characterized in that, The inner wall of the cylindrical housing is provided with an annular track, the outer surface of the upper grinding block is provided with an annular groove that matches the annular track, the outer surface of the upper grinding block is also provided with ring teeth, and the cylindrical housing is provided with a gear drive assembly that meshes with the ring teeth.

8. The coal pulverized coal feeding device for thermal power generation according to claim 1, characterized in that, The columnar casing has multiple pulverized coal outlets, which are arranged circumferentially and evenly.

9. The coal pulverized coal feeding device for thermal power generation according to claim 5, characterized in that, It also includes a frame, on which the cylindrical housing and the return auger are fixedly mounted.

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