A magnetic suspension precise coal feeding system and control method for rotary kiln

Abstract

The invention discloses a magnetic suspension precision coal feeding system for a rotary kiln, comprising a coal powder bin and a control system, a coal delivery pipe is arranged below the coal powder bin, a rotor scale is arranged between the coal powder bin and the coal delivery pipe, one end of the coal delivery pipe is connected with a magnetic suspension blower, the other end of the coal delivery pipe is connected with a coal injection pipe, the rotor scale and the magnetic suspension blower are electrically connected with the control system respectively, and the control system adjusts the operating speed of the magnetic suspension blower according to the amount of coal fed, so that the air output of the magnetic suspension blower is highly matched with the amount of coal fed; the invention has a simple overall structure, can reduce the water and oil content in the coal feeding process, prevent condensation or unfavorable material feeding phenomena, and has a high degree of automation and simple operation, and can reduce energy consumption, play a role in energy saving and consumption reduction, and reduce noise and vibration.

Description

Technical Field

[0001] The present invention relates to the technical field of coal feeding systems, and more specifically, to a magnetic suspension precision coal feeding system and a control method for a rotary kiln. Background Art

[0002] The cement industry is one of the pillar industries of my country's national economy. Cement rotary kiln has become the main equipment for calcining cement clinker in modern cement production. Building intelligent cement production plants and improving the degree of automation, integration and greening of cement enterprises have become important development directions of the cement industry.

[0003] The calcination process of cement clinker in the rotary kiln is the key link that determines the quality of cement clinker. In the prior art, the rotary kiln is fed with a coal feeding system. The specific working mode of the existing coal feeding system is as follows: the coal powder passes through the silo slide valve of the coal powder silo and the scale slide valve of the rotor scale, enters the rotor part through the inlet soft connection, is taken away by the rotor compartment, rotates to reach the unloading area, and is blown out from the discharge port by the wind of the Roots blower at the bottom, and is sent to the burner through a pipeline.

[0004] It can be seen that the existing coal feeding system has a simple overall structure, a low degree of automation, and the control of the coal feeding amount mainly depends on the knowledge and experience of the operating engineer.

[0005] Moreover, in the existing coal feeding system, when Roots blowers are used for coal feeding, lubricating oil needs to be added to the Roots blowers during operation, and there is no water vapor filtration system. The air blown out contains too much water and oil. When the air assists the flow, the water is brought to the coal powder, resulting in an increase in the water and oil content of the coal powder, condensation or unfavorable feeding, and in severe cases, the coal injection pipe may be blocked.

[0006] During the operation of the equipment, the pulverized coal scale and the Roots blower work independently, and technicians are required to adjust the coal discharge amount of the pulverized coal scale and the air volume of the Roots blower in real time according to the on-site usage conditions.

[0007] The air volume of Roots blower can only be adjusted by the opening of the vent valve, that is, when a small air volume is needed, the vent valve needs to be opened to discharge the excess air, resulting in energy waste.

[0008] Roots blowers generate a lot of noise and vibration during operation, causing harm to on-site workers. Summary of the invention

[0009] The main technical problem to be solved by the present invention is to provide a magnetic suspension precision coal feeding system and control method for a rotary kiln which has a simple overall structure, can reduce the water and oil content in the coal delivery process, prevent condensation or adverse material feeding phenomena, and has a high degree of automation, simple operation, and can reduce energy consumption, play a role in energy saving and consumption reduction, and reduce noise and vibration.

[0010] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0011] A magnetic suspension precision coal feeding system for a rotary kiln comprises a pulverized coal bin and a control system, a coal delivery pipe is arranged below the pulverized coal bin, a rotor scale is arranged between the pulverized coal bin and the coal delivery pipe, one end of the coal delivery pipe is connected to a magnetic suspension blower, and the other end of the coal delivery pipe is connected to a coal injection pipe, the rotor scale and the magnetic suspension blower are electrically connected to the control system respectively, and the control system adjusts the operating speed of the magnetic suspension blower according to the amount of coal fed, so that the air output of the magnetic suspension blower is highly matched with the amount of coal fed.

[0012] The following is a further optimization of the above technical solution by the present invention:

[0013] A bin slide valve is provided between the pulverized coal bin and the rotor scale, and a scale slide valve is provided between the rotor scale and the coal delivery pipe.

[0014] Further optimization: the control system includes a central controller, a communication end of the central controller is connected to a host computer via optical fiber communication, and the central controller is bidirectionally electrically connected to a rotor scale control module and a magnetic suspension blower control module.

[0015] Further optimization: the rotor scale control module includes a first signal acquisition unit and a valve drive control unit, and the first signal acquisition unit is electrically connected to the output end of the rotor scale; the rotor scale weighs the weight of the pulverized coal output from the pulverized coal bin to obtain a pulverized coal weight signal, and the pulverized coal weight signal is collected by the first signal acquisition unit and transmitted to the central controller.

[0016] Further optimization: the valve drive control unit is bidirectionally electrically connected to the control end and the output end of the scale slide valve, and the valve drive control unit outputs a drive signal for adjusting the valve opening of the scale slide valve; by adjusting the valve opening of the scale slide valve, the coal feeding speed can be adjusted.

[0017] Further optimization: the magnetic levitation blower control module includes a second signal acquisition unit, a magnetic bearing drive control unit and a motor drive control unit; the second signal acquisition unit is electrically connected to the signal output ends of the pressure sensor and the flow sensor, and the second signal acquisition unit detects the pressure signal and flow signal obtained by the pressure sensor and the flow sensor, and transmits them to the central controller.

[0018] Further optimization: the magnetic bearing drive control unit is electrically connected to the magnetic bearing assembly of the magnetic levitation motor, and the magnetic bearing drive control unit is used to energize the magnetic bearing assembly to control the suspension state of the magnetic levitation motor rotor.

[0019] Further optimization: the motor drive control unit is electrically connected to the magnetic levitation motor of the magnetic levitation blower, and the motor drive control unit outputs a control signal for controlling the rotation speed of the magnetic levitation motor to adjust the air volume of the magnetic levitation blower.

[0020] A magnetic suspension precise coal feeding control method for a rotary kiln, the control method is based on the magnetic suspension precise coal feeding system for a rotary kiln, the control method includes an ignition operation process, wherein the ignition operation process is performed according to the following steps:

[0021] S1, the control system starts, and the ignition mode is run on the upper computer. The upper computer transmits the ignition coal quantity value to the central controller. After receiving the ignition coal quantity value, the central controller adjusts the rotor scale coal quantity to the ignition coal quantity value according to the ignition coal quantity value;

[0022] S2, determine whether the amount of coal under the rotor scale is the set value, if not, execute step S1, if yes, execute step S3;

[0023] S3, the central controller controls the rotation of the magnetic suspension blower through the magnetic suspension blower control module, and adjusts the speed of the magnetic suspension blower through the motor drive control unit to reduce the output air volume of the magnetic suspension blower to below the normal mode;

[0024] S4, determine whether the air volume of the magnetic suspension blower has been matched, if not, execute step S3, if yes, execute step S5;

[0025] S5. The central controller sends a control signal to drive the burner to start. At this time, the burner is automatically turned on for ignition according to the amount of coal put in and the current air volume of the blower.

[0026] The following is a further optimization of the above technical solution by the present invention:

[0027] The control method further includes a normal operation process, which is performed according to the following steps:

[0028] Z1. After the ignition operation process is completed, the control system automatically executes the normal operation process, or directly executes the operation mode through the host computer selection;

[0029] Z2. During operation, the operator sets the preset threshold value of coal feeding amount according to the demand, and then the upper computer transmits the preset threshold value of coal feeding amount to the central controller through communication. After receiving the value of coal feeding amount, the central controller adjusts the coal feeding amount of the rotor scale to the set value according to the value;

[0030] Z3, determine whether the amount of coal under the rotor scale is the set value, if not, execute step Z2, if yes, execute step Z4;

[0031] Z4. The central controller adjusts the speed of the magnetic suspension blower through the motor drive control unit to match the output air volume of the magnetic suspension blower with the amount of coal discharged;

[0032] Z5. Determine whether the air volume of the magnetic suspension blower matches the amount of coal fed. If not, execute step Z4; if yes, execute step Z1.

[0033] The present invention adopts the above technical scheme, which is ingenious in conception and reasonable in structure, realizes intelligent and precise coal feeding of cement rotary kiln, greatly reduces labor costs; reduces the energy consumption of the coal feeding system of the cement plant, and reduces the noise generated by the system; reduces the water content of coal powder by adding a water vapor filter device at the inlet of the magnetic levitation blower, and reduces the oil content of coal powder by utilizing the oil-free and friction-free characteristics of the magnetic levitation blower, thereby reducing the risk of blockage of the coal injection pipe, making the system run more stably, and reducing labor maintenance costs; realizes real-time automatic adjustment of the air volume of the magnetic levitation blower according to the amount of coal fed, without the need for personnel to adjust the operating status of the blower, and there will be no energy loss caused by excessive air volume.

[0034] The present invention is further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the structure of a coal feeding system in an embodiment of the present invention;

[0036] Figure 2 is a schematic diagram of a control system in an embodiment of the present invention;

[0037] Figure 3 This is a coal feeding amount control diagram in an embodiment of the present invention;

[0038] Figure 4 4 is a control logic diagram of a control system in an embodiment of the present invention.

[0039] In the figure: 1- coal powder bin; 2- bin slide valve; 3- rotor scale; 4- scale slide valve; 5- coal delivery pipe; 7- connecting hose; 8- magnetic suspension blower. DETAILED DESCRIPTION

[0040] like Figure 1-4 As shown, a magnetic suspension precision coal feeding system for a rotary kiln includes a pulverized coal bin 1 and a control system. A coal delivery pipe 5 is arranged below the pulverized coal bin 1, a rotor scale 3 is arranged between the pulverized coal bin 1 and the coal delivery pipe 5, one end of the coal delivery pipe 5 is connected to a magnetic suspension blower 8, and the other end of the coal delivery pipe 5 is connected to a coal injection pipe. The rotor scale 3 and the magnetic suspension blower 8 are electrically connected to the control system respectively, and the control system adjusts the operating speed of the magnetic suspension blower 8 according to the amount of coal put in, so that the air output of the magnetic suspension blower 8 is highly matched with the amount of coal put in.

[0041] A bin slide valve 2 is provided between the pulverized coal bin 1 and the rotor scale 3 , and the bin slide valve 2 is used to control whether the pulverized coal bin 1 outputs pulverized coal.

[0042] The bin slide valve 2 is opened to output the coal powder, and the coal powder falls onto the rotor scale 3. The rotor scale 3 is used to weigh the weight of the coal powder.

[0043] A scale slide valve 4 is provided between the rotor scale 3 and the coal delivery pipe 5 , and the scale slide valve 4 is used to control whether the rotor scale 3 outputs coal powder.

[0044] The rotor scale 3 weighs the pulverized coal, and the scale slide valve 4 is opened to output the pulverized coal, at which time the pulverized coal falls into the coal delivery pipe 5, and the magnetic suspension blower 8 outputs wind power to blow the pulverized coal into the coal injection pipe to achieve coal feeding.

[0045] With this design, the magnetic suspension blower 8 can be used to transport the coal powder by wind, thereby reducing the noise on site and the water and oil content of the coal powder.

[0046] The magnetic suspension blower 8 is composed of a magnetic suspension motor, an impeller, etc. The magnetic suspension motor is an oil-free, friction-free, high-speed, energy-saving rotating machine.

[0047] The air inlet of the magnetic levitation blower 8 is connected to a water vapor filtering device, and the water vapor filtering device can filter the moisture in the air and reduce the humidity of the air entering the magnetic levitation blower 8.

[0048] With this design, under normal circumstances, the air contains moisture, and a water vapor filter is added at the air inlet of the magnetic suspension blower 8 to reduce air humidity, ensure that coal powder does not agglomerate and block the coal injection pipe, and reduce the maintenance frequency of the coal injection pipe.

[0049] In addition, the magnetic suspension blower 8 will increase the air temperature and reduce the humidity during the compression process, which is more conducive to the full combustion of the coal powder and achieves the purpose of energy saving and consumption reduction.

[0050] The control system comprises a central controller, a communication end of the central controller is connected to a host computer via optical fiber communication, and the central controller is bidirectionally electrically connected to a rotor scale control module and a magnetic suspension blower control module.

[0051] The rotor scale control module includes a first signal acquisition unit and a valve drive control unit. The first signal acquisition unit is electrically connected to the output end of the rotor scale 3 .

[0052] The rotor scale 3 weighs the weight of the pulverized coal output from the pulverized coal bin 1 to obtain a pulverized coal weight signal, and the pulverized coal weight signal is collected by the first signal collection unit and then transmitted to the central controller.

[0053] The valve drive control unit is bidirectionally electrically connected to the control end and the output end of the scale slide valve 4 , and the valve drive control unit outputs a drive signal for adjusting the valve opening of the scale slide valve 4 .

[0054] The valve opening of the scale slide valve 4 can be adjusted to adjust the coal feeding speed.

[0055] The magnetic suspension blower control module includes a second signal acquisition unit, a magnetic bearing drive control unit and a motor drive control unit.

[0056] The second signal acquisition unit is electrically connected to the signal output ends of the pressure sensor and the flow sensor. The second signal acquisition unit detects the pressure signal and the flow signal obtained by the pressure sensor and the flow sensor, and transmits them to the central controller.

[0057] The pressure sensor and flow sensor are arranged inside the magnetic suspension blower and are used to measure the blower outlet pressure and outlet air volume.

[0058] The magnetic bearing drive control unit is electrically connected to the magnetic suspension bearing assembly of the magnetic suspension motor, and the magnetic bearing drive control unit is used to energize the magnetic suspension bearing assembly to control the suspension state of the magnetic suspension motor rotor.

[0059] In this embodiment, the magnetic bearing assembly is a prior art, and the magnetic bearing assembly is electrically installed in the magnetic motor of the magnetic blower 8 .

[0060] The motor drive control unit is electrically connected to the magnetic levitation motor of the magnetic levitation blower 8, and the motor drive control unit outputs a control signal for controlling the rotation speed of the magnetic levitation motor, thereby controlling the rotation speed of the magnetic levitation blower 8 to adjust the air volume of the magnetic levitation blower 8.

[0061] In this embodiment, the host computer and the central controller communicate via optical fiber. Due to the long communication distance of optical fiber, the central controller can be placed at the equipment use site and the host computer can be placed in the customer's control room to achieve remote control.

[0062] The upper computer is provided with a preset threshold value of coal feeding amount and a value of coal amount for ignition, and the preset threshold value of coal feeding amount is set according to the use conditions.

[0063] After the preset threshold of the coal feeding amount is set in the host computer, the value will be transmitted to the central controller through communication. After receiving the coal feeding amount value, the central controller calculates the valve opening and coal feeding speed of the rotor scale according to the value, so as to control the rotor scale control module. The rotor scale has a coal powder weighing function, and can feed back the coal powder weight data to the central controller in real time to realize closed-loop control and improve control accuracy.

[0064] The coal feeding amount = unit coal powder weight * coal feeding speed; the blower speed is positively correlated with the blower flow rate and is adjusted through the PID fuzzy control principle; the flow rate = k * coal feeding amount + b.

[0065] Where k represents the empirical coefficient and b represents the empirical constant.

[0066] The prepared coal powder first enters the coal powder bin for storage. When the bin slide valve 2 is opened, the coal powder enters the rotor scale 3. The rotor scale 3 measures the weight of the coal powder. The scale slide valve 4 is used to control the amount of coal. The magnetic levitation blower 8 is connected to the coal delivery pipe 5 through a flexible connection. The wind generated by the magnetic levitation blower 8 carries the coal powder into the coal injection pipe, and then enters the rotary kiln through the coal injection pipe for combustion.

[0067] It can be seen that the present invention controls the rotor scale 3 and the magnetic suspension blower 8 in linkage, so that the system automatically adjusts the valve switching frequency of the rotor scale 3 and the operating speed of the magnetic suspension blower 8 according to the setting system of different coal loading amounts, thereby reducing labor costs and reducing losses caused by manual operation errors. At the same time, according to the algorithm, the air output of the blower is highly matched with the coal loading amount, so that the system can not only accurately feed coal according to the setting, but also reduce energy losses caused by excessive air volume.

[0068] The coal feeding system includes an operation mode and an ignition mode. The upper computer is provided with an ignition coal amount value. When the coal feeding system operates in the ignition mode, the upper computer transmits the ignition coal amount value to the central controller through communication. After receiving the ignition coal amount value, the central controller adjusts the rotor scale coal amount to the ignition coal amount value according to the ignition coal amount value, controls the air volume output by the magnetic suspension blower 8 to match the coal amount, and then drives the burner to start.

[0069] In the described operating mode, the upper computer transmits the preset threshold value of the coal feeding amount to the central controller through communication. After receiving the coal feeding amount value, the central controller calculates the valve opening of the rotor scale and the coal feeding speed according to the value, thereby controlling the rotor scale control module. At the same time, according to the algorithm, the air output of the blower is highly matched with the coal feeding amount.

[0070] like Figure 1-4 As shown, the present invention also provides a magnetic suspension precise coal feeding control method for a rotary kiln. The control method is based on the magnetic suspension precise coal feeding system for a rotary kiln. The control method includes an ignition operation process, wherein the ignition operation process is performed according to the following steps:

[0071] S1. The control system starts, and then the ignition mode is run on the upper computer. At this time, the upper computer transmits the ignition coal quantity value to the central controller through communication. After receiving the ignition coal quantity value, the central controller adjusts the rotor scale coal quantity to the ignition coal quantity value according to the ignition coal quantity value.

[0072] S2. Determine whether the amount of coal under the rotor scale is the set value. If not, proceed to step S1; if yes, proceed to step S3.

[0073] When judging whether the coal amount under the rotor scale is the set value, the coal amount under the rotor scale is fed back to the central controller, and the central controller compares the coal amount under the rotor scale with the coal amount value under ignition.

[0074] When the coal quantity under the rotor scale is equal to the coal quantity under ignition, it means that the coal quantity under the rotor scale is qualified;

[0075] When the coal amount under the rotor scale is less than the coal amount under ignition, it means that the coal amount under the rotor scale is unqualified. At this time, the central controller increases the coal amount under the rotor scale.

[0076] When the coal amount under the rotor scale is greater than the ignition coal amount, it means that the coal amount under the rotor scale is unqualified. At this time, the central controller is used to adjust the coal amount under the small rotor scale.

[0077] S3. The central controller controls the rotation of the magnetic levitation blower 8 through the magnetic levitation blower control module, and adjusts the speed of the magnetic levitation blower 8 through the motor drive control unit, reducing the output air volume of the magnetic levitation blower 8 to below the normal mode to ensure that the wind generated by the blower will not blow out the flame.

[0078] S4, determine whether the air volume of the magnetic suspension blower has been matched, if not, execute step S3, if yes, execute step S5.

[0079] When determining whether the air volume of the magnetic suspension blower has been matched, the output real-time air volume of the magnetic suspension blower 8 is fed back to the central controller, and the central controller compares the output real-time air volume with the preset air volume. When the output real-time air volume is equal to the preset air volume, it indicates that the air volume of the magnetic suspension blower has been matched;

[0080] When the real-time output air volume is less than the preset air volume, it indicates that the air volume of the magnetic levitation blower does not match. At this time, the central controller adjusts the speed of the magnetic levitation blower 8 through the motor drive control unit so that the real-time output air volume is equal to the preset air volume.

[0081] When the output real-time air volume is greater than the preset air volume, it indicates that the air volume of the magnetic levitation blower does not match. At this time, the central controller adjusts the speed of the magnetic levitation blower 8 through the motor drive control unit so that the output real-time air volume is equal to the preset air volume.

[0082] S5. The central controller sends a control signal to drive the burner to start. At this time, the burner is automatically turned on for ignition according to the amount of coal put in and the current air volume of the blower.

[0083] The control method further includes a normal operation process, which is performed according to the following steps:

[0084] Z1. After the ignition operation process is completed, the control system automatically executes the normal operation process, or directly executes the operation mode through the host computer selection.

[0085] Z2. During operation, the operator can set the preset threshold of coal feeding amount according to the demand, and then the upper computer transmits the set preset threshold of coal feeding amount to the central controller through communication. After receiving the coal feeding amount value, the central controller adjusts the coal discharge amount of the rotor scale to the set value according to the value.

[0086] Z3. Determine whether the amount of coal under the rotor scale is the set value. If not, proceed to step Z2; if yes, proceed to step Z4.

[0087] When judging whether the coal amount under the rotor scale is the set value, the coal amount under the rotor scale is fed back to the central controller, and the central controller compares the coal amount under the rotor scale with the set value.

[0088] When the coal quantity under the rotor scale is equal to the set value, it means that the coal quantity under the rotor scale is qualified;

[0089] When the coal amount under the rotor scale is less than the set value, it means that the coal amount under the rotor scale is unqualified. At this time, the central controller increases the coal amount under the rotor scale.

[0090] When the amount of coal put down by the rotor scale is greater than the set value, it means that the amount of coal put down by the rotor scale is unqualified. At this time, the central controller is used to adjust the amount of coal put down by the small rotor scale.

[0091] Z4. The central controller adjusts the speed of the magnetic suspension blower 8 through the motor drive control unit to match the output air volume of the magnetic suspension blower 8 with the coal discharge volume.

[0092] Z5. Determine whether the air volume of the magnetic suspension blower 8 matches the coal quantity. If not, execute step Z4; if yes, execute step Z1.

[0093] When determining whether the air volume of the magnetic suspension blower has been matched, the output real-time air volume of the magnetic suspension blower 8 in the normal operating mode is fed back to the central controller, and the central controller compares the output real-time air volume with the normal mode preset air volume. When the output real-time air volume is equal to the normal mode preset air volume, it indicates that the air volume of the magnetic suspension blower has been matched;

[0094] When the real-time output air volume is less than the preset air volume in the normal mode, it indicates that the air volume of the magnetic levitation blower does not match. At this time, the central controller adjusts the speed of the magnetic levitation blower 8 through the motor drive control unit so that the real-time output air volume is equal to the preset air volume in the normal mode.

[0095] When the real-time output air volume is greater than the preset air volume in the normal mode, it indicates that the air volume of the magnetic levitation blower does not match. At this time, the central controller adjusts the speed of the magnetic levitation blower 8 through the motor drive control unit so that the real-time output air volume is equal to the preset air volume in the normal mode.

[0096] For those skilled in the art, according to the teachings of the present invention, without departing from the principles and spirit of the present invention, changes, modifications, substitutions and variations made to the implementation methods are still within the protection scope of the present invention.

Claims

1. A magnetic suspension precision coal feeding system for a rotary kiln, comprising a coal powder bin (1) and a control system, characterized in that: A coal delivery pipe (5) is provided below the coal powder bin (1), a rotor scale (3) is provided between the coal powder bin (1) and the coal delivery pipe (5), one end of the coal delivery pipe (5) is connected to a magnetic suspension blower (8), and the other end of the coal delivery pipe (5) is connected to a coal injection pipe, the rotor scale (3) and the magnetic suspension blower (8) are respectively electrically connected to a control system, and the control system adjusts the operating speed of the magnetic suspension blower (8) according to the amount of coal discharged, so that the air volume of the magnetic suspension blower (8) is highly matched with the amount of coal discharged; The control system includes a central controller, a communication end of the central controller is connected to a host computer via optical fiber communication, and the central controller is bidirectionally electrically connected to a rotor scale control module and a magnetic suspension blower control module; The rotor scale control module comprises a first signal acquisition unit and a valve drive control unit, the first signal acquisition unit being electrically connected to an output end of the rotor scale (3); the rotor scale (3) weighs the weight of the pulverized coal output from the pulverized coal bin (1) to obtain a pulverized coal weight signal, the pulverized coal weight signal being collected by the first signal acquisition unit and then transmitted to the central controller; The magnetic suspension blower control module includes a second signal acquisition unit, a magnetic bearing drive control unit and a motor drive control unit; The second signal acquisition unit is electrically connected to the signal output ends of the pressure sensor and the flow sensor. The second signal acquisition unit detects the pressure signal and the flow signal obtained by the pressure sensor and the flow sensor, and transmits them to the central controller. The motor drive control unit is electrically connected to the magnetic suspension motor of the magnetic suspension blower (8), and the motor drive control unit outputs a control signal for controlling the rotation speed of the magnetic suspension motor to adjust the air volume of the magnetic suspension blower (8).

2. A magnetic suspension precise coal feeding system for a rotary kiln according to claim 1, characterized in that: A bin slide valve (2) is provided between the pulverized coal bin (1) and the rotor scale (3), and a scale slide valve (4) is provided between the rotor scale (3) and the coal delivery pipe (5).

3. A magnetic suspension precise coal feeding system for a rotary kiln according to claim 2, characterized in that: The valve drive control unit is bidirectionally electrically connected to the control end and the output end of the scale slide valve (4); the valve drive control unit outputs a drive signal for adjusting the valve opening of the scale slide valve (4); and by adjusting the valve opening of the scale slide valve (4), the coal feeding speed can be adjusted.

4. A magnetic suspension precise coal feeding system for a rotary kiln according to claim 3, characterized in that: The magnetic bearing drive control unit is electrically connected to the magnetic suspension bearing assembly of the magnetic suspension motor, and the magnetic bearing drive control unit is used to energize the magnetic suspension bearing assembly to control the suspension state of the magnetic suspension motor rotor.

5. A magnetic suspension precise coal feeding control method for a rotary kiln, characterized in that: The control method is based on the magnetic suspension precision coal feeding system for a rotary kiln according to any one of claims 1 to 4, and the control method includes an ignition operation process, wherein the ignition operation process is performed according to the following steps: S1, the control system starts, and the ignition mode is run on the upper computer. The upper computer transmits the ignition coal quantity value to the central controller. After receiving the ignition coal quantity value, the central controller adjusts the rotor scale coal quantity to the ignition coal quantity value according to the ignition coal quantity value; S2, determine whether the amount of coal under the rotor scale is the set value, if not, execute step S1, if yes, execute step S3; S3, the central controller controls the rotation of the magnetic suspension blower (8) through the magnetic suspension blower control module, and adjusts the speed of the magnetic suspension blower (8) through the motor drive control unit, thereby reducing the output air volume of the magnetic suspension blower (8) to below the normal mode; S4, determine whether the air volume of the magnetic suspension blower has been matched, if not, execute step S3, if yes, execute step S5; S5. The central controller sends a control signal to drive the burner to start. At this time, the burner is automatically turned on for ignition according to the amount of coal put in and the current air volume of the blower.

6. A magnetic suspension precise coal feeding control method for a rotary kiln according to claim 5, characterized in that: The control method further includes a normal operation process, which is performed according to the following steps: Z1. After the ignition operation process is completed, the control system automatically executes the normal operation process, or directly executes the operation mode through the host computer selection; Z2. During operation, the operator sets the preset threshold value of coal feeding amount according to the demand, and then the upper computer transmits the preset threshold value of coal feeding amount to the central controller through communication. After receiving the value of coal feeding amount, the central controller adjusts the coal feeding amount of the rotor scale to the set value according to the value; Z3, determine whether the amount of coal under the rotor scale is the set value, if not, execute step Z2, if yes, execute step Z4; Z4, the central controller adjusts the speed of the magnetic suspension blower (8) through the motor drive control unit to match the output air volume of the magnetic suspension blower (8) with the amount of coal discharged; Z5. Determine whether the air volume of the magnetic suspension blower (8) matches the amount of coal fed. If not, proceed to step Z4; if yes, proceed to step Z1.

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