Transformation method for coping with deep peak regulation of coal mill

Abstract

The invention relates to the technical field of coal mill transformation, in particular to a deep peak regulation coping transformation method for a coal mill, which is based on a medium-speed roller type coal mill for transformation and comprises the following steps: replacing an asynchronous motor with a permanent magnet synchronous motor; the gear ratio of an input-stage spiral bevel gear pair of an original planetary reducer is changed, and the output rotating speed of the planetary reducer is increased; the distance between the output shaft of the permanent magnet synchronous motor and the output shaft of the planetary reducer is adjusted, and a permanent magnet speed regulator is installed between the permanent magnet synchronous motor and the planetary reducer; a loading system of the grinding roller is replaced with a reactive force hydraulic variable loading system; and replacing the static separator with a dynamic separator. According to the application, the problem of insufficient output of the coal mill caused by poor coal quality can be solved, and the problem of poor stability and economy of the coal mill when the coal mill runs in a deep peak-shaving low-load mode can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of coal mill transformation, and in particular to a method for transforming a coal mill to cope with deep peak regulation. Background Art

[0002] The pace of clean and low-carbon transformation of my country's power system will further accelerate. Coal-fired power will gradually transform from the main power source for providing electricity to a supporting and regulating power source that gives equal importance to electricity. The proportion of installed capacity and power generation will decrease, and the flexible adjustment capability and clean and efficient level will need to be improved.

[0003] In the existing technology, the calorific value of thermal coal used in thermal power plants is getting lower and lower, and seriously deviates from the design coal, so there are new requirements and challenges for coal mills. When using low calorific value coal, the coal mill needs to be modified under full load operation; the stability and economy of the coal mill under low load conditions during deep peak regulation. Speeding up the reducer is a conventional solution for coal mill speed improvement, but after speeding up, the coal mill is unstable when running at low load, it is easy to vibrate, the coal consumption per unit increases, and the economy is poor.

[0004] Therefore, in response to the above problems, coal mills in thermal power plants urgently need an overall upgrading and transformation method to solve the problem of insufficient output caused by deteriorating coal quality, as well as the poor stability and economy of coal mills when operating at deep peak load. Summary of the invention

[0005] In order to solve the problem of insufficient output caused by deterioration of coal quality, as well as the stability and economy problems during deep peak-shaving and low-load operation, this application provides.

[0006] The coal mill transformation method for deep peak regulation provided by the present invention adopts the following technical solutions:

[0007] A method for modifying a coal mill to cope with deep peak regulation is based on the modification of a medium-speed roller coal mill, comprising: replacing an asynchronous motor with a permanent magnet synchronous motor; replacing the original input-stage spiral bevel gear pair of a planetary reducer with a spiral bevel gear pair with a relatively small number of teeth, thereby increasing the output speed of the planetary reducer; adjusting the distance between the output shaft of the permanent magnet synchronous motor and the output shaft of the planetary reducer, and installing a permanent magnet speed regulator between the permanent magnet synchronous motor and the planetary reducer; replacing the loading system of the grinding roller with a reaction force hydraulic variable loading system; and replacing the static separator with a dynamic separator.

[0008] Optionally, the permanent magnet synchronous motor is of a dual-axis type, installed horizontally, with an IC611 cooling method, a protection level not lower than IP54, a power factor ≥0.98, and a motor guaranteed efficiency ≥96%.

[0009] Optionally, replacing the original input-stage spiral bevel gear pair of the planetary reducer with a spiral bevel gear pair with a larger tooth ratio includes: replacing the original bevel gear and input-stage bevel gear shaft with a bevel gear with a smaller number of teeth and a matching bevel gear shaft; the replaced bevel gear adopts an extended epicycloidal tooth system and is a hardened gear with a tooth surface hardness of HRC58-HRC62.

[0010] Optionally, the permanent magnet speed regulator is a disc type permanent magnet speed regulator, a cylinder type permanent magnet speed regulator or a double cylinder type permanent magnet speed regulator.

[0011] Optionally, the reaction force hydraulic variable loading system can apply forces in the upper and lower directions to the grinding roller, so as to offset a part of the grinding roller's own weight when the coal mill is running at low load; the loading pressure and reaction pressure of the reaction force hydraulic variable loading system are both controlled by a proportional relief valve; the proportional relief valve is adjusted according to the change of the coal feed amount of the coal mill, so as to realize the adjustment of the loading pressure of the reaction force hydraulic variable loading system.

[0012] Optionally, the dynamic separator is a combined dynamic and static dynamic separator; the transmission mode of the dynamic separator is belt drive or gear drive.

[0013] Optionally, a speed sensor is provided at the output shaft of the permanent magnet speed governor; the speed sensor is communicatively connected to a DCS system, so that the rotational speed of the output shaft of the permanent magnet speed governor measured by the speed sensor is displayed on the DCS system, and the rotational speed of the permanent magnet speed governor is associated with the coal feed rate of the coal mill, thereby realizing the association between the rotational speed of the permanent magnet speed governor and the power generation load.

[0014] Optionally, the reaction force hydraulic variable loading system is communicatively connected to a DCS system, so that the loading force and reaction force of the reaction force hydraulic variable loading system are displayed on the DCS system, and the loading force and reaction force of the reaction force hydraulic variable loading system are associated with the coal feed rate of the coal mill, thereby realizing the association between the loading force and reaction force of the reaction force hydraulic variable loading system and the power generation load.

[0015] Optionally, the loading force and reaction force of the reaction force hydraulic variable loading system are controlled by a hydraulic pump station system; the hydraulic pump station system is automatically controlled, online controlled and remotely controlled by a combination of lower computer PLC control and upper computer configuration software control.

[0016] Optionally, the dynamic separator is driven by a frequency converter and a variable frequency motor; the dynamic separator, the frequency converter and the variable frequency motor are communicatively connected to a DCS system; the rotation speed of the variable frequency motor rotor is automatically and remotely adjusted by the DCS system, thereby adjusting the rotation speed of the dynamic separator and changing the fineness of the coal powder at the powder outlet of the dynamic separator.

[0017] As described above, the method for transforming the coal mill to cope with deep peak regulation of the present invention has at least the following beneficial effects:

[0018] 1. By replacing the asynchronous motor with a permanent magnet synchronous motor, the defects of the asynchronous motor, such as low power factor, low efficiency and high energy consumption, are overcome, the requirements of the coal mill's heavy-load and frequent starting load are met, and it is more energy-efficient.

[0019] 2. By replacing the spiral bevel gear pair at the input stage of the planetary reducer, changing the gear ratio, and increasing the output speed of the planetary reducer, the unit consumption of the permanent magnet synchronous motor at low load of the coal mill can be effectively reduced, thereby improving the economy of coal mill pulverizing.

[0020] 3. By adjusting the distance between the output shaft of the permanent magnet synchronous motor and the output shaft of the planetary reducer, and installing a permanent magnet speed regulator between the permanent magnet synchronous motor and the planetary reducer, the output speed of the planetary reducer can be reduced at low load, the power consumption of coal grinding can be reduced, and the vibration can be reduced. The coal mill can operate stably at a load below 20%, while reducing the wear of the grinding parts; the output speed of the planetary reducer can also be increased at full load conditions, thereby increasing the grinding output and making up for the insufficient output caused by the deterioration of coal quality.

[0021] 4. By replacing the roller loading system with a reaction force hydraulic variable loading system, part of the roller's deadweight can be offset, reducing the roller's power consumption when running at low load.

[0022] 5. By replacing the static separator with a dynamic separator, the coal mill's adaptability to changes in coal types is improved, allowing the boiler to operate economically and stably. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of a coal mill after being transformed by the transformation method of the coal mill to cope with deep peak regulation of the present application.

[0024] Figure 2 It is a schematic diagram of the working principle of the reaction force variable loading system.

[0025] Figure numerals: 1, permanent magnet synchronous motor; 2, permanent magnet speed regulator; 3, planetary reducer; 4, grinding body; 5, dynamic separator; 6, reaction force hydraulic variable loading system; 61, oil cylinder; 611, loading chamber; 612, back pressure chamber; 7, grinding disc; 8, grinding roller; 9, overflow valve. DETAILED DESCRIPTION

[0026] The following is an explanation of the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the features in the following embodiments and the embodiments can be combined with each other without conflict. It should also be understood that the terms used in the embodiments of the present invention are intended to describe specific embodiments, rather than to limit the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are usually carried out under conventional conditions or according to the conditions recommended by the manufacturers.

[0027] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0028] This application discloses a method for modifying a coal mill to cope with deep peak load regulation, which is based on the modification of a medium-speed roller coal mill. Figure 1 shown.

[0029] The method comprises: replacing the asynchronous motor with a permanent magnet synchronous motor 1. Replacing the original input stage spiral bevel gear pair of the planetary reducer 3 with a spiral bevel gear pair with a relatively small number of teeth, and increasing the output speed of the planetary reducer 3. Adjusting the spacing between the output shaft of the permanent magnet synchronous motor 1 and the output shaft of the planetary reducer 3, and installing a permanent magnet speed regulator 2 between the permanent magnet synchronous motor 1 and the planetary reducer 3. Replacing the loading system of the grinding roller 8 with a reaction force hydraulic variable loading system 6. Replacing the static separator with a dynamic separator 5.

[0030] Figure 1 In the embodiment, the output end of the permanent magnet synchronous motor 1 is connected to the input end of the planetary reducer 3 through the permanent magnet speed regulator 2, and the permanent magnet speed regulator 2 also has the function of a coupling. The output end of the planetary reducer 3 drives the grinding disc 7 in the mill body 4 to rotate, so that the grinding roller 8 grinds the material on the grinding disc 7. The dynamic separator 5 is located at the upper end of the mill body 4, and the coal powder is blown into the dynamic separator 5 by the airflow at the bottom of the mill body 4 for separation.

[0031] Transformation of asynchronous motors: Existing coal mills generally use three-phase asynchronous motors. Three-phase asynchronous motors have low power factor, low efficiency, and high energy consumption, so they are replaced with permanent magnet synchronous motors 1. Permanent magnet synchronous motors 1 have high starting torque and can meet the requirements of coal mills for heavy-loaded and frequent starting loads.

[0032] Specifically, the replaced permanent magnet synchronous motor 1 is a dual-axis type, horizontally installed, with a cooling method of IC611, a protection level not less than IP54, a power factor ≥ 0.98, and a motor guaranteed efficiency ≥ 96%. In addition, the three-phase asynchronous motor and the permanent magnet synchronous motor 1 are different in appearance, so the original installation structure for installing the three-phase asynchronous motor needs to be modified so that it can be adapted to install the above-mentioned permanent magnet synchronous motor 1.

[0033] Reconstruction of planetary reducer 3: The load of the coal mill is generally 25% to 100%. It is unstable and vibrates greatly when running at low load. When the thermal power plant is in deep peak regulation, the low-load operation of the coal mill becomes normal, the unit consumption of coal milling increases exponentially, and the economic efficiency of coal mill powder production is poor. In order to cope with this situation, it is necessary to transform the planetary reducer 3. After replacing the spiral bevel gear pair of the input stage of the planetary reducer 3 and changing the gear ratio, when the output speed of the permanent magnet synchronous motor 1 is the same, the output speed of the star reducer is higher, thereby effectively reducing the unit consumption of the permanent magnet synchronous motor 1 at low load of the coal mill and improving the economic efficiency of coal mill powder production.

[0034] At the same time, since the gear ratio of the input stage spiral bevel gear pair of the planetary reducer 3 is reduced, the replaced spiral bevel gear pair adopts an extended epicycloidal tooth system and is a hardened gear with a tooth surface hardness of HRC58-HRC62, such as HRC58, HRC60 or HRC62. In this way, while increasing the output speed of the planetary reducer 3, the bevel gear is guaranteed to have sufficient strength, which helps to increase the service life of the planetary reducer 3.

[0035] Renovation of installing permanent magnet speed regulator 2: In the original coal mill, the output shaft of the motor is directly connected to the planetary reducer 3. Therefore, it is necessary to first adjust the distance between the output shaft of the permanent magnet synchronous motor 1 and the output shaft of the planetary reducer 3 before the permanent magnet speed regulator 2 can be installed between the permanent magnet synchronous motor 1 and the planetary reducer 3. The permanent magnet speed regulator 2 is a technology that uses magnetic force to achieve torque transmission without mechanical contact. Its structure can be a disc-type permanent magnet speed regulator 2, a cylinder-type permanent magnet speed regulator 2, and a double-cylinder-type pass-through speed regulator. The permanent magnet speed regulator 2 adjusts the effective coupling area of ​​the conductor and the permanent magnet through an electric actuator, changes the torque transmitted between the two, realizes adjustable and controllable torque output, and achieves the purpose of load speed regulation and energy saving.

[0036] The permanent magnet speed regulator 2 transmits torque through the air gap between the conductor rotor and the permanent magnet, and realizes the torque output at the load end by changing the coupling area size to achieve the purpose of speed regulation, while the speed of the permanent magnet synchronous motor 1 remains unchanged. The permanent magnet speed regulator 2 is a purely mechanical non-contact structure without mechanical connection, which can isolate vibration, allow impact loads, and extend the service life of various components of the transmission system (bearings, seals, etc.). It effectively eliminates power harmonic pollution and electromagnetic interference, and avoids the transmission of vibration between the permanent magnet synchronous motor 1 and the load. The permanent magnet speed regulator also has the advantages of strong environmental adaptability and can work normally in harsh environments such as humidity, dust, flammable and explosive, severe harmonics, and large power grid fluctuations. The speed regulation operation of the coal mill is particularly important when the thermal power unit is transformed into an adjustable power supply. Reducing the output speed of the planetary reducer 3 at low load can reduce the power consumption of coal milling and reduce vibration. The coal mill can operate stably at a load below 20%, while reducing the wear of the grinding parts. Under full load conditions, the output speed of the planetary reducer 3 is increased to improve the grinding output and make up for the insufficient output caused by the deterioration of coal quality.

[0037] In a preferred embodiment of the present application, the modification method of the coal mill for deep peak regulation also includes: setting a speed sensor at the output shaft of the permanent magnet speed regulator 2. The speed sensor is connected to the DCS system for communication, so that the speed of the output shaft of the permanent magnet speed regulator 2 measured by the speed sensor is displayed on the DCS system, and the speed of the permanent magnet speed regulator 2 is associated with the coal feed of the coal mill, thereby realizing the association between the speed of the permanent magnet speed regulator 2 and the power generation load. In this way, the automatic operation and maintenance of the permanent magnet synchronous motor 1, the planetary reducer 3, and the permanent magnet speed regulator 2 of the coal mill can be realized.

[0038] Modification of the loading system of the grinding roller 8: Since the grinding roller 8 itself has a large deadweight, when the coal mill is running at low load, the deadweight of the grinding roller 8 will cause excessive pressure between the grinding roller 8 and the grinding disc 7, increasing the power consumption of the grinding roller 8. Therefore, it is necessary to load a reaction force on the grinding roller 8 to offset part of the deadweight of the grinding roller 8. The reaction force hydraulic variable loading system 6 can apply forces in both the upper and lower directions to the grinding roller 8 to offset part of the deadweight of the grinding roller 8 when the coal mill is running at low load. The loading pressure and reaction pressure of the reaction force hydraulic variable loading system 6 are controlled by the proportional relief valve 9. The proportional relief valve 9 is adjusted according to the change of the coal feed of the coal mill to realize the adjustment of the loading pressure of the reaction force hydraulic variable loading system 6. The proportional relief valve 9 is connected to the DCS system for communication. According to the change of the coal feed of the coal mill, the control signal of the proportional relief valve 9 can be adjusted online in the DCS system, thereby realizing the online real-time adjustment of the reaction force hydraulic variable loading system 6.

[0039] In a preferred embodiment of the present application, the loading force and reaction force of the reaction force hydraulic variable loading system 6 are controlled by the hydraulic pump station system. The hydraulic pump station system is automatically controlled, online controlled and remotely controlled by combining the lower computer PLC control and the upper computer configuration software control.

[0040] The hydraulic pump station system supplies oil to the upper and lower chambers of the oil cylinder 61 through a double pump. The loading chamber 611 is high pressure and small flow, and the back pressure chamber 612 is low pressure and large flow. The pressure of the two oil circuits is adjusted by two proportional relief valves 9. There are two plug-in check valves in the valve group. When the grinding roller 8 is lowered, the loading chamber 611 can be replenished with oil to ensure the speed of lowering the grinding roller 8.

[0041] In a preferred embodiment of the present application, the transformation method of the coal mill to cope with deep peak regulation also includes: connecting the reaction force hydraulic variable loading system 6 to the DCS system in communication, so that the loading force and reaction force of the reaction force hydraulic variable loading system 6 are displayed on the DCS system, and the loading force and reaction force of the reaction force hydraulic variable loading system 6 are associated with the coal feed of the coal mill, thereby realizing the association between the loading force and reaction force of the reaction force hydraulic variable loading system 6 and the power generation load. In this way, the automatic operation and maintenance of the reaction force hydraulic variable loading system 6 is realized.

[0042] Renovation of static separator: As the static separator has poor adjustment performance, poor fineness, insufficient adaptability to coal type changes, and affects the economic and stable operation of the boiler, the static separator is replaced with a dynamic separator 5. The dynamic separator 5 is installed above the coal mill body.

[0043] Specifically, in the modification method of the coal mill for deep peak regulation of the present application, the dynamic separator 5 is driven by a frequency converter and a variable frequency motor. The dynamic separator 5, the frequency converter and the variable frequency motor are connected to the DCS system for communication. The DCS system automatically and remotely adjusts the speed of the variable frequency motor rotor, thereby adjusting the speed of the dynamic separator 5 and changing the fineness of the coal powder at the powder outlet of the dynamic separator 5. This satisfies the needs of users for different coal powder finenesses, expands the range of coal types for power plants, and reduces fuel costs. In this way, automatic operation and maintenance of the dynamic separator 5 is achieved.

[0044] The coal mill transformation method for deep peak regulation in this application has the following advantages:

[0045] 1. By replacing the asynchronous motor with a permanent magnet synchronous motor 1, the defects of the asynchronous motor, such as low power factor, low efficiency and high energy consumption, are overcome, the requirements of the coal mill's heavy-load and frequent starting load are met, and it is more energy-efficient.

[0046] 2. By replacing the input-stage spiral bevel gear pair of the planetary reducer 3, changing the gear ratio, and increasing the output speed of the planetary reducer 3, the unit consumption of the permanent magnet synchronous motor 1 at low load of the coal mill can be effectively reduced, thereby improving the economy of coal mill pulverizing.

[0047] 3. By adjusting the distance between the output shaft of the permanent magnet synchronous motor 1 and the output shaft of the planetary reducer 3, and installing the permanent magnet speed regulator 2 between the permanent magnet synchronous motor 1 and the planetary reducer 3, the output speed of the planetary reducer 3 can be reduced at low load, the power consumption of coal grinding can be reduced, the vibration can be reduced, the coal mill can operate stably at a load below 20%, and the wear of the grinding parts can be reduced; the output speed of the planetary reducer 3 can also be increased at full load conditions, the grinding output can be increased, and the output problem caused by the deterioration of coal quality can be compensated.

[0048] 4. By replacing the loading system of the grinding roller 8 with a reaction force hydraulic variable loading system 6, part of the deadweight of the grinding roller 8 can be offset, thereby reducing the power consumption of the grinding roller 8 when running at low load.

[0049] 5. By replacing the static separator with a dynamic separator 5, the coal mill's adaptability to changes in coal types is improved, allowing the boiler to operate economically and stably.

[0050] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for transforming a coal mill to cope with deep peak regulation, characterized in that: Based on the medium speed roller mill, the transformation includes: Replacing the asynchronous motor with a permanent magnet synchronous motor (1); The input-stage spiral bevel gear pair of the original planetary reducer (3) is replaced with a spiral bevel gear pair with a relatively small number of teeth, thereby increasing the output speed of the planetary reducer (3); Adjusting the distance between the output shaft of the permanent magnet synchronous motor (1) and the output shaft of the planetary reducer (3), and installing a permanent magnet speed regulator (2) between the permanent magnet synchronous motor (1) and the planetary reducer (3); The loading system of the grinding roller (8) is replaced with a reaction force hydraulic variable loading system (6); Replace the static separator with a dynamic separator (5).

2. The method according to claim 1, characterized in that: The permanent magnet synchronous motor (1) is of a double-shaft type, installed horizontally, with a cooling method of IC611, a protection level not lower than IP54, a power factor ≥0.98, and a motor guaranteed efficiency ≥96%.

3. The method according to claim 1, characterized in that The method of replacing the original input-stage spiral bevel gear pair of the planetary reducer (3) with a spiral bevel gear pair with a relatively small number of teeth comprises: Replace the original bevel gear and input-stage bevel gear shaft with a bevel gear with a smaller number of teeth and a matching bevel gear shaft; The replaced bevel gear adopts an extended epicycloidal tooth system and is a hardened gear with a tooth surface hardness of HRC58-HRC62.

4. The method according to claim 1, characterized in that: The permanent magnet speed regulator (2) is a disc-type permanent magnet speed regulator (2), a barrel-type permanent magnet speed regulator (2) or a double-barrel-type permanent magnet speed regulator (2).

5. The method according to claim 1, characterized in that: The reaction force hydraulic variable loading system (6) can exert forces in both the upper and lower directions on the grinding roller (8), so as to offset a part of the deadweight of the grinding roller (8) when the coal mill is running at a low load; The loading pressure and the reaction pressure of the reaction force hydraulic variable loading system (6) are both controlled by a proportional relief valve (9); The proportional relief valve (9) is adjusted according to the change of the coal feed rate of the coal mill, so as to adjust the loading pressure of the reaction force hydraulic variable loading system (6).

6. The method according to claim 1, characterized in that: The dynamic separator (5) is a dynamic and static combined dynamic separator (5); the transmission mode of the dynamic separator (5) is belt transmission or gear transmission.

7. The method according to claim 1, characterized in that: A speed sensor is arranged at the output shaft of the permanent magnet speed regulator (2); the speed sensor is connected to a DCS system for communication, so that the speed of the output shaft of the permanent magnet speed regulator (2) measured by the speed sensor is displayed on the DCS system, and the speed of the permanent magnet speed regulator (2) is associated with the coal feed rate of the coal mill, thereby realizing the association between the speed of the permanent magnet speed regulator (2) and the power generation load.

8. The method according to claim 1 or 5, characterized in that: The reaction force hydraulic variable loading system (6) is communicatively connected to a DCS system, so that the loading force and reaction force of the reaction force hydraulic variable loading system (6) are displayed on the DCS system, and the loading force and reaction force of the reaction force hydraulic variable loading system (6) are associated with the coal feed rate of the coal mill, thereby realizing the association between the loading force and reaction force of the reaction force hydraulic variable loading system (6) and the power generation load.

9. The method according to claim 8, characterized in that Controlling the loading force and reaction force of the reaction force hydraulic variable loading system (6) by means of a hydraulic pump station system; The hydraulic pump station system is automatically controlled, online controlled and remotely controlled by combining the lower computer PLC control and the upper computer configuration software control.

10. The method according to claim 1, characterized in that The dynamic separator (5) is driven by a frequency converter and a variable frequency motor; Connecting the dynamic separator (5), the frequency converter and the variable frequency motor to a DCS system for communication; The DCS system is used to automatically and remotely adjust the rotation speed of the variable frequency motor rotor, thereby adjusting the rotation speed of the dynamic separator (5) and changing the fineness of the coal powder at the powder outlet of the dynamic separator (5).

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