Auxiliary air blowing device for medium speed coal mill
By installing a heating device at the raw coal inlet of the coal mill and a rake-type purging device above the grinding bowl, the problem of insufficient output caused by coal combustion deviation in the coal mill was solved, resulting in reduced power consumption and improved coal powder separation efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HUADIAN LUOHE POWER GENERATION CO LTD
- Filing Date
- 2025-07-28
- Publication Date
- 2026-07-07
Smart Images
Figure CN224462890U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of coal mill technology, and specifically relates to an auxiliary blowing device for a medium-speed coal mill. Background Technology
[0002] Coal mills are used to grind raw coal to a fine enough powder for effective combustion in a furnace. They are widely used in industries such as power, metallurgy, and building materials. The maximum output of a coal mill is mainly limited by the following factors: mill specifications; raw coal characteristics; and coal powder fineness. Due to the current high coal prices, most power plants are using coal types that deviate significantly from their design coal types, resulting in a decrease in the grinding capacity of the coal mills and affecting their output.
[0003] Adjusting the gap between coal mills, increasing the wind speed, and adjusting the separator baffles can increase output, but this will make the coal powder coarser, increase fly ash and large slag combustibles, and lead to a decrease in boiler efficiency.
[0004] The invention disclosed in CN119175149A is a sludge treatment system that utilizes a coal mill to dry sludge and couple it to coal-fired power generation. The key technical points include a coal mill with a sludge cylinder and a coal cylinder coaxially arranged inside. The coal cylinder is located inside the sludge cylinder. An air inlet pipe connects the sludge cylinder and a rotating hot air nozzle ring. A rotating shaft is fixedly connected to the grinding disc and coaxially arranged inside the coal cylinder. A primary crushing component and a secondary crushing component are arranged between the sludge cylinder and the coal cylinder, with the primary crushing component located above the secondary crushing component. The rotating shaft drives the primary and secondary crushing components to rotate. Its main focus is on preventing wet sludge from adhering to the grinding disc and rollers, maintaining the normal operation of the coal mill, improving the grinding and screening efficiency of wet sludge, ensuring a continuous supply of mixed coal powder and sludge powder fuel, and improving the power generation efficiency of the power plant boiler. However, its structure is complex and does not address the purging air.
[0005] The utility model disclosed in announcement number CN217093750U is a non-centrally fed solid shaft driven coal powder separator. Its key technical features include a solid shaft drive device, an upper shell, and a lower shell. The solid shaft drive device is mounted on the upper shell; its upper side is positioned above the upper shell; its lower side is positioned inside the upper shell; the upper and lower shells can be tightly connected and fixedly joined; a rotor is positioned below the solid shaft drive device; stationary blades are positioned on the outer side of the rotor. For dynamic separators used in non-centrally fed pulverizing equipment, the hollow shaft drive is simplified to a solid shaft drive, simplifying the transmission structure. The separator components adopt a modular design, and the solid shaft driven separator occupies less space. However, it emphasizes the transmission structure, simplifying the hollow shaft drive to a solid shaft drive, resulting in simpler powder pipe connection and less turbulence from purging air. Summary of the Invention
[0006] The purpose of this invention is to address the shortcomings of the existing technology by providing an auxiliary air blowing device for a medium-speed coal mill, thereby increasing the output of the coal mill and reducing its power consumption.
[0007] To solve the above technical problems, the technical solution adopted by this utility model is as follows:
[0008] An auxiliary blowing device for a medium-speed coal mill includes a coal mill and grinding rollers and grinding bowls installed inside the coal mill. A raw coal heating device is provided at the raw coal inlet of the coal mill, and a blowing device is provided above the grinding bowl. The blowing device is connected to an annular air duct via a connecting vertical pipe, and the annular air duct is connected to a disturbance air source.
[0009] The purging device has a rake-shaped structure, and the rake-shaped structure is arranged parallel to the grinding surface of the grinding bowl at intervals and has multiple purging nozzles.
[0010] The blowing device is configured to correspond one-to-one with the grinding bowl and is evenly distributed at intervals.
[0011] The purging device is provided in 3 to 5 sets.
[0012] The annular air duct is fixed on the side wall above the raw coal discharge port of the coal mill.
[0013] The purging device is also equipped with multiple nozzles with upward-facing openings near the coal drop pipe.
[0014] The purging device has three nozzles with upward-facing openings near the coal drop pipe.
[0015] The disturbance air source can be hot air or cold air.
[0016] The outer end face of the rake-shaped structure is spaced 10-30cm from the grinding surface of the grinding bowl.
[0017] The outer end face of the rake-shaped structure is 15cm away from the grinding surface of the grinding bowl.
[0018] The beneficial effects of this utility model are:
[0019] (1) The auxiliary blowing device of the medium-speed coal mill, by setting a raw coal heating device at the raw coal inlet of the coal mill and setting a blowing device above the grinding bowl, can improve the grindability of the raw coal by pre-drying the raw coal, reduce the power consumption of the coal mill motor, and effectively improve the grinding output of the coal mill; while the blowing device, by disturbing the blowing air, disturbs the coal powder flow field in the grinding bowl, so that qualified coal powder is separated in time and carried into the furnace for combustion, avoiding multiple crushing of qualified coal powder and increasing the motor output.
[0020] (2) The purging device introduces a new hot air source from outside the coal mill to purge the grinding on the grinding bowl, thereby enhancing the disturbance and carrying capacity of the flow field and allowing the ground coal powder to enter the first and second stage screening more quickly. Attached Figure Description
[0021] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation
[0022] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification.
[0023] This utility model provides an auxiliary air blowing device for a medium-speed coal mill, such as... Figure 1 As shown.
[0024] An auxiliary air blowing device for a medium-speed coal mill includes a coal mill and grinding rollers and grinding bowls installed inside the coal mill. A raw coal heating device 4 is provided at the raw coal inlet of the coal mill, and a blowing device 3 is provided above the grinding bowl. The blowing device 3 is connected to an annular air duct 1 via a connecting vertical pipe 5. The annular air duct 1 is connected to a disturbance air source. For easy installation, the annular air duct 1 is fixed on the side wall above the raw coal discharge port 2 of the coal mill. The disturbance air source can be hot air or cold air.
[0025] In this embodiment, the purging device 3 has a rake-shaped structure, and the rake-shaped structure is arranged parallel to the grinding surface of the grinding bowl at intervals and has multiple purging nozzles. Near the coal drop pipe, the purging device 3 also has multiple upward-facing nozzles, forming a rotating airflow that moves upward, disturbing and purging the raw coal. Preferably, the purging device 3 is arranged in a one-to-one correspondence with the grinding bowl, and is evenly distributed at intervals. There are 3 to 5 sets of purging devices 3. In this embodiment, there are 3 sets of purging devices 3 corresponding to the grinding roller, with 3 upward-facing nozzles. The outer end face of the rake-shaped structure is spaced 10 to 30 cm from the grinding surface of the grinding bowl. In this embodiment, the outer end face of the rake-shaped structure is spaced 15 cm from the grinding surface of the grinding bowl.
[0026] The following description, in conjunction with specific embodiments, further illustrates the point:
[0027] A raw coal heating device 4 is installed at the raw coal inlet of the coal mill. The primary air source of the raw coal heating device 4 is used to introduce hot air to dry the raw coal, and one DN150 electric damper and one DN150 adjustable electric damper are installed.
[0028] The purging device 3 has an opening on the inclined surface under the top cover of the separator on the channel side of the coal mill to introduce the disturbance air source into the coal mill and connect it to the annular air duct; then, a Φ89 connecting vertical pipe is led along the powder discharge side of the grinding roller to connect to the purging pipe of the lower purging device.
[0029] Each grinding roller outlet is equipped with a purge pipe. The purge nozzles point downwards, disturbing and lifting the finely ground powder, which is then carried to the separator by the rotating primary air. Meanwhile, three upward nozzles installed near the coal drop pipe create a rotating airflow that moves upwards, disturbing and purging the raw coal, separating the qualified coal powder from the raw coal, and carrying it to the outlet powder pipe with the rotating airflow. This can simultaneously reduce the temperature of the coal powder mixture at the coal mill outlet, reducing the probability of coal powder explosion; it can also reduce primary air resistance, reduce primary air fan power consumption, increase coal mill output by 8-10%, and reduce coal consumption per unit by 1-1.5 kWh / t or more.
[0030] The solution has been applied in practice, and the system is operating well. The coal consumption per unit of coal mill has been reduced by 1.89 kW.h / t of coal, and the maximum output has been increased by 11.69%.
[0031] If this patent uses terms such as "first" and "second" to define components, those skilled in the art should know that the use of "first" and "second" is merely for the convenience of describing this utility model and simplifying the description, and the above terms have no special meaning.
[0032] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.
[0033] In the description of this utility model, it should be understood that the terms "front", "rear", "left", "right", "center", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of this utility model and simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this utility model.
Claims
1. An auxiliary air blowing device for a medium-speed coal mill, characterized in that: It includes a coal mill and grinding rollers and grinding bowls installed inside the coal mill. A raw coal heating device is provided at the raw coal inlet of the coal mill, and a purging device is provided above the grinding bowl. The purging device is connected to an annular air duct via a connecting vertical pipe, and the annular air duct is connected to a disturbance air source.
2. The auxiliary air blowing device for a medium-speed coal mill according to claim 1, characterized in that: The purging device has a rake-shaped structure, and the rake-shaped structure is arranged parallel to the grinding surface of the grinding bowl at intervals and has multiple purging nozzles.
3. The auxiliary air blowing device for a medium-speed coal mill according to claim 1, characterized in that: The blowing device is configured to correspond one-to-one with the grinding bowl and is evenly distributed at intervals.
4. The auxiliary air blowing device for a medium-speed coal mill according to claim 1, characterized in that: The purging device is provided in 3 to 5 sets.
5. An auxiliary air blowing device for a medium-speed coal mill according to any one of claims 1 to 4, characterized in that: The annular air duct is fixed on the side wall above the raw coal discharge port of the coal mill.
6. The auxiliary air blowing device for a medium-speed coal mill according to claim 5, characterized in that: The purging device is also equipped with multiple nozzles with upward-facing openings near the coal drop pipe.
7. The auxiliary air blowing device for a medium-speed coal mill according to claim 6, characterized in that: The purging device has three nozzles with upward-facing openings near the coal drop pipe.
8. The auxiliary air blowing device for a medium-speed coal mill according to claim 1, characterized in that: The disturbance air source can be hot air or cold air.
9. The auxiliary air blowing device for a medium-speed coal mill according to claim 2, characterized in that: The outer end face of the rake-shaped structure is spaced 10-30cm from the grinding surface of the grinding bowl.
10. The auxiliary air blowing device for a medium-speed coal mill according to claim 9, characterized in that: The outer end face of the rake-shaped structure is 15cm away from the grinding surface of the grinding bowl.