Coal blockage prevention control system for steel ball coal mill

Abstract

The utility model discloses an anti-blocking coal control system for a steel ball coal mill, which belongs to the technical field of coal mills and comprises an integrated control system, a hot air pipe and a cold air pipe. The opening degree of the hot air pipe is controlled through a hot secondary air door, and the opening degree of the cold air pipe is controlled through a cold secondary air door. The hot air pipe and the cold air pipe are jointly divided into two paths of mixed air pipes through a mixed isolation air door, and the two paths of mixed air pipes are connected with spiral conveyors at the driving end and the non-driving end of the coal mill respectively; a capacity air door for controlling the opening degree is arranged on the mixed air pipe; a mixing box is arranged at the lower end of the coal dropping pipe, and a bypass air pipe is branched from the mixing air pipe at the driving end of the coal mill and is connected into the mixing box; a temperature sensor is arranged on the separator at the outlet of the coal mill; the input end of the integrated control system is connected with the temperature sensor, and the output end is connected with the bypass damper, the capacity damper and the spiral conveyor. The device is used for solving the problem of blockage caused by moisture of raw coal in an existing coal mill pulverizing system, the production efficiency of the coal mill pulverizing system is improved, and the labor cost is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of coal mills, and specifically relates to an anti-blocking coal control system for a steel ball coal mill. Background Art

[0002] The coal mills in our factory are BBD series double-in and double-out steel ball coal mills, which are the main equipment of the direct-fired coal pulverizing system in thermal power plants. One coal mill is equipped with two coal feeders. The upper end of the coal dropping pipe at the connection of the coal feeder outlet in our factory is a square opening, and the lower end is a cylindrical barrel structure; coal is prone to adhere and bridge at the entrance of the cylindrical barrel, resulting in coal blockage. Especially in rainy seasons, the coal blocks carry water, causing more serious retention of coal mud on the pipe wall and resulting in blockage, affecting the normal operation of the coal mill. From March to May 2022, during continuous rainy weather with wet coal, the coal dropping pipes of the coal feeders of Mills 1, 3, 5, and 6 in Boiler 1 frequently became blocked. According to statistics, the coal dropping pipes of the same coal feeder had more than 10 blockages continuously within a month. In severe cases, the same coal feeder had 2 blockages within 24 hours and two coal feeders of different mills were blocked simultaneously at the same time. After the blockage occurred, the coal mill needed to be stopped for manual cleaning of the accumulated coal. 3 - 4 workers needed 5 hours to work simultaneously, which not only affected production efficiency but also increased production costs and the manual labor intensity was high.

[0003] Effect after transformation: During the rainy season from March to May 2024, the coal blockage situation of the coal feeder decreased significantly, with only 1 - 2 occasional blockages in a month. Content of the Utility Model

[0004] In view of the above problems, the utility model provides an anti-blocking coal control system for a steel ball coal mill, which is used to solve the blockage problem caused by wet raw coal in the existing coal pulverizing system, can improve the production efficiency of the coal pulverizing system of the coal mill, and reduce labor costs.

[0005] To achieve the above object, the technical solution adopted by the utility model is:

[0006] An anti-blocking coal control system for a steel ball coal mill includes a coal feeder and a coal mill; the coal feeder is connected to the screw conveyor of the coal mill through a vertical coal dropping pipe;

[0007] It further includes an integrated control system, a hot air pipe, and a cold air pipe; the hot air pipe controls the opening degree through a hot secondary air damper, and the cold air pipe controls the opening degree through a cold secondary air damper; the hot air pipe and the cold air pipe jointly pass through a mixing isolation damper and are divided into two mixing air pipes to be respectively connected to the screw conveyors at both ends of the coal mill; a capacity damper for controlling the opening degree is arranged on the mixing air pipe;

[0008] A mixing box is provided at the lower end of the coal dropping pipe. A bypass air duct branches off from the mixing air duct at the driving end of the coal mill and is connected to the mixing box. A bypass air damper is provided on the bypass air duct. A temperature sensor for sensing the temperature at the outlet of the coal mill is provided on the separator at the outlet of the coal mill.

[0009] The input end of the integrated control system is connected to the temperature sensor, and the output end is connected to the bypass air damper, the capacity air damper, and the screw conveyor.

[0010] As a further improvement of the above solution, the mixing box is cylindrical in shape, installed inside the coal dropping pipe, and its diameter is smaller than the inner diameter of the coal dropping pipe.

[0011] As a further improvement of the above solution, the inner diameter at the connection between the coal dropping pipe and the coal feeder is enlarged to 700 mm; the diameter of the coal dropping pipe is set to 600 mm.

[0012] As a further improvement of the above solution, a hot air box is provided between the mixing air duct and the screw conveyor.

[0013] As a further improvement of the above solution, the conveying shaft of the screw conveyor is a hollow shaft, and the hollow shaft is used for air conveying.

[0014] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0015] When the raw coal is wet, the temperature sensor of the separator senses that the outlet temperature is low. According to different coal types, when the separator temperature is lower than a certain value, for example, 63 °C for bituminous lignite, the bypass air damper is interlocked to open to a certain opening degree, generally 30%-50%, and at the same time, the coal feeding amount of the coal feeder is interlocked to decrease, and the capacity air damper of the coal mill is closed to reduce the output of the coal mill; after the bypass air damper is opened, the high temperature of the bypass air is used to dry the raw coal, remove the moisture of the coal type, and avoid coal blockage caused by the adhesion of the raw coal to the wall.

[0016] When the coal is wet, it is reflected that the separator temperature is lower than normal. When it is lower than a certain value, an alarm is issued, the bypass air damper is interlocked to open to dry the raw coal, and at the same time, the coal feeding amount is decreased and the capacity air damper of the coal mill is closed to reduce the output of the coal mill, so as to avoid coal blockage in the coal dropping pipe caused by feeding a large amount of wet coal for a long time. Brief Description of the Drawings

[0017] Figure 1 It is a schematic structural principle diagram of this system.

[0018] Figure 2 It is a schematic structural diagram of the screw conveyor.

[0019] In the figure: 1. Inlet electric door; 2. Coal feeder; 3. Outlet electric door; 4. Mixing box; 5. Screw conveyor; 6. Bypass air damper; 7. Capacity air damper; 8. Sealing air damper; 9. Mixing isolation air damper; 10. Hot secondary air damper; 11. Cold secondary air damper; 12. Coal mill; 13. Separator; 14. Coal dropping pipe; 51. Conveyor shaft. Specific implementation mode

[0020] In order to enable those skilled in the art to better understand the technical solution, the present utility model will be described in detail below in conjunction with embodiments. The description of this part is only exemplary and explanatory, and should not have any restrictive effect on the protection scope of the present utility model.

[0021] As Figure 1 shown, the specific solution of this embodiment is as follows: An anti-blocking coal control system for a steel ball coal mill, including a coal feeder 2 and a coal mill 12; the coal feeder 2 is connected to the screw conveyor 5 of the coal mill 12 through a vertical coal dropping pipe 14;

[0022] It also includes an integrated control system, a hot air pipe and a cold air pipe; the opening degree of the hot air pipe is controlled by a hot secondary air damper 10, and the opening degree of the cold air pipe is controlled by a cold secondary air damper 11; the hot air pipe and the cold air pipe jointly pass through a mixing isolation air damper 9 and are divided into two mixed air pipes to be respectively connected to the screw conveyors 5 at both ends of the coal mill 12; a capacity air damper 7 for controlling the opening degree is arranged on the mixed air pipe;

[0023] A mixing box 4 is arranged at the lower end of the coal dropping pipe 14, and a bypass air pipe branched from the mixed air pipe at the driving end of the coal mill 12 is connected into the mixing box 4; a bypass air damper 6 is arranged on the bypass air pipe; a temperature sensor for sensing the temperature at the outlet of the coal mill 12 is arranged on the separator 13 at the outlet of the coal mill 12;

[0024] The input end of the integrated control system is connected to the temperature sensor, and the output end is connected to the bypass air damper 6, the capacity air damper 7, and the screw conveyor 5. The integrated control system is generally a single-chip microcomputer control system or a PLC control system.

[0025] The mixing box 4 is cylindrical in shape, installed inside the coal dropping pipe 14, and its diameter is smaller than the inner diameter of the coal dropping pipe 14.

[0026] The inner diameter of the connection between the coal dropping pipe 14 and the coal feeder 2 is set to be enlarged to 700 mm; the diameter of the coal dropping pipe 14 is set to be 600 mm.

[0027] As Figure 2 shown, the conveyor shaft 51 of the screw conveyor 5 is a hollow shaft, and the hollow shaft is used for air transportation.

[0028] The specific working principle of the present utility model:

[0029] The BBD series double-inlet and double-outlet coal mill is equipped with two coal feeders, namely A and B. Coal enters the coal mill cylinder from the raw coal bunker through the coal feeder, via the coal dropping pipe and screw conveyors (drive end and non-drive end) for grinding. After being separated by the coal powder separators on the A and B sides, the qualified pulverized coal passes through the powder pipes to the boiler burners (each separator has two powder pipes), and the unqualified pulverized coal returns to the coal mill cylinder through the return powder pipe for further grinding.

[0030] Raw coal is put into the feed hopper at the upper end of the coal feeder 2. After opening the inlet electric door 1, the raw coal enters the coal feeder 2 and then enters the coal dropping pipe 14 after passing through the outlet electric door 3. Then it falls downward into the mixing box 4. According to the output temperature sensed by the temperature sensor in the separator 13 at the output end of the coal mill 12, when it is determined that the temperature is too low, the bypass air door 6 is opened, and the mixed air branches from the mixed air pipe and enters the bypass air pipe to heat and dry the raw coal in the mixing box 4.

[0031] 1. Enlarge the diameter of the coal dropping pipe 14 and the diameter of the outlet electric door 3 between the outlet of the coal feeder 2 and the screw conveyor 5 of the coal mill 12 to avoid bottlenecks.

[0032] 2. There is a hot air pipe and a cold air pipe at the inlet of the coal mill 12, each controlled by a hot secondary air door 10 and a cold secondary air door 11, and then passes through a mixing isolation air door 9 and is divided into two paths to the screw conveyors 5 at the drive end and non-drive end of the coal mill 12 respectively, and then enters the coal mill cylinder.

[0033] 3. A mixing box 4 is set on the coal dropping pipe 14. A bypass air pipe is led from the mixed air at the inlet of the coal mill 12 to the mixing box 4. The high-temperature mixed air (about 280 °C) can dry the raw coal. The bypass air door 6 is closed during the normal operation of the coal mill 12. There is a temperature measuring point on the separator 13 at the outlet of the coal mill 12.

[0034] When the coal is wet, the temperature of the separator 13 is low. According to different coal types, when the temperature of the separator 13 is lower than a certain value, for example, 63 °C for bituminous brown coal, the integrated control system interlocks to open the bypass air door 6 to a certain opening (30%-50%), and at the same time interlocks to reduce the coal feeding amount of the coal feeder 2 and close the capacity air door 7 of the coal mill 12 to reduce the output of the coal mill 12. After the bypass air door 6 is opened, the high-temperature bypass air is used to dry the raw coal, remove the moisture of the coal type, and avoid coal blockage caused by the adhesion of raw coal to the wall.

[0035] 4. When the coal is wet, it is reflected in the lower temperature of the separator 13 than normal. When it is lower than a certain value, the integrated control system controls to issue an alarm, interlocks to open the bypass air door 6 to dry the raw coal, and at the same time reduces the coal feeding amount and closes the capacity air door 7 of the coal mill 12 to reduce the output of the coal mill 12, avoiding coal blockage in the coal dropping pipe 14 caused by feeding a large amount of wet coal for a long time.

[0036] Embodiment:

[0037] 1. Enlarge the diameter of the coal chute 14 between the outlet of the coal feeder 2 and the screw conveyor 5 to the coal mill 12 and the diameter of the outlet motorized valve 3 to avoid bottlenecks.

[0038] 2. There is a hot air duct and a cold air duct at the inlet of the coal mill 12, each controlled by a hot primary air damper and a cold primary air damper, and then pass through a mixing isolation damper 9, and are divided into two paths to the screw conveyors 5 at the driving end and the non-driving end of the coal mill 12 respectively, and then enter the cylinder body of the coal mill 12.

[0039] 3. A mixing box 4 is arranged on the coal chute 14, and a bypass air duct is led from the mixed air at the inlet of the coal mill 12 to the mixing box 4. The high temperature of the mixed air (about 280 °C) can dry the raw coal. The bypass damper 6 is closed during the normal operation of the coal mill 12. There is a temperature measuring point on the separator 13 at the outlet of the coal mill 12. When the coal is wet, the temperature of the separator 13 is low. According to different coal types, when the temperature of the separator 13 is lower than a certain value (63 °C for bituminous brown coal), the integrated control system controls and interlocks to open the bypass damper 6 to a certain opening (30%-50%), and at the same time interlocks to reduce the coal feeding amount of the coal feeder 2 and close the capacity damper 7 of the coal mill 12 to reduce the output of the coal mill 12. After the bypass damper 6 is opened, the high temperature of the bypass air is used to dry the raw coal and remove the moisture of the coal type to avoid blockage of the coal caused by wet and sticky raw coal sticking to the wall.

[0040] It should be noted that in this article, the terms "including", "comprising" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Specific examples are used in this article to elaborate on the principles and implementation modes of the technical solutions of the present invention. The above examples are only used to help understand the method and its core idea of the present invention. The above is only the preferred embodiment of the present invention. It should be pointed out that due to the limited nature of written expression and objectively there are infinite specific structures. For those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements, refinements or changes can be made, or the above technical features can be combined in an appropriate manner; these improvements, refinements, changes or combinations, or directly applying the concept and technical solution of the present invention to other occasions without improvement, should all be regarded as the protection scope of the present invention.

Claims

1. An anti-blocking coal control system for a steel ball coal mill, comprising a coal feeder (2) and a coal mill (12); the coal feeder (2) is connected to the screw conveyor (5) of the coal mill (12) through a vertical coal dropping pipe (14); characterized in that, it further comprises an integrated control system, a hot air pipe and a cold air pipe; the opening degree of the hot air pipe is controlled by a hot secondary air damper (10), and the opening degree of the cold air pipe is controlled by a cold secondary air damper (11); the hot air pipe and the cold air pipe jointly pass through a mixing isolation damper (9) and are divided into two mixing air pipes to be respectively connected to the screw conveyors (5) at both ends of the coal mill (12); a capacity damper (7) for controlling the opening degree is arranged on the mixing air pipe; a mixing box (4) is arranged at the lower end of the coal dropping pipe (14), and a bypass air pipe is branched from the mixing air pipe at the driving end of the coal mill (12) and connected into the mixing box (4); a bypass damper (6) is arranged on the bypass air pipe; a temperature sensor for sensing the temperature at the outlet of the coal mill (12) is arranged on the separator (13) at the outlet of the coal mill (12); the input end of the integrated control system is connected to the temperature sensor, and the output end is connected to the bypass damper (6), the capacity damper (7), and the screw conveyor (5).

2. The anti-blocking coal control system for a steel ball coal mill according to claim 1, characterized in that, The mixing box (4) is cylindrical in shape and is installed inside the coal dropping pipe (14), and its diameter is smaller than the inner diameter of the coal dropping pipe (14).

3. The anti-blocking coal control system for a steel ball coal mill according to claim 1, characterized in that, The inner diameter of the connection between the coal dropping pipe (14) and the coal feeder (2) is enlarged to 700 mm; the diameter of the coal dropping pipe (14) is set to 600 mm.

4. The anti-blocking coal control system for a steel ball coal mill according to claim 1, characterized in that The conveying shaft (51) of the screw conveyor (5) is a hollow shaft, and the hollow shaft is used for air conveyance.

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