CN216125835U - Coal mill for thermal power generation - Google Patents
Coal mill for thermal power generation Download PDFInfo
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- CN216125835U CN216125835U CN202121493900.6U CN202121493900U CN216125835U CN 216125835 U CN216125835 U CN 216125835U CN 202121493900 U CN202121493900 U CN 202121493900U CN 216125835 U CN216125835 U CN 216125835U
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- coal pulverizer
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Abstract
The utility model provides a thermal power coal mill, which relates to the technical field of coal mills in thermal power plants, and comprises: a drum and a drive device; the driving device is used for driving the roller to rotate; the driving device includes: a first motor and a second motor; the first motor and the second motor are respectively arranged on two sides of the roller. The technical scheme provided by the utility model can reduce the failure probability of the coal mill so as to ensure the stable operation of the coal mill.
Description
Technical Field
The utility model belongs to the technical field of coal mills in thermal power plants, and particularly relates to a thermal power generation coal mill.
Background
Coal mills are machines for breaking up and grinding coal briquettes into coal dust, which are important auxiliary equipment for coal dust furnaces.
At present, all coal mills for power generation use asynchronous motors, and the driving part of the coal mills is of a traditional structure of the asynchronous motor plus a speed reducer.
Because the coal mill adopts the traditional structure of an asynchronous motor and a speed reducer, when the electric load requirement changes, the coal mill is continuously started to operate, and the following problems exist.
1. The coal feeding amount is small, the steel ball and the lining plate are directly collided and abraded, the abrasion speed is rapidly accelerated, and the cost of the steel ball and the lining plate is huge;
2. the coal grinding machine has small powder quantity, basically unchanged power consumption and waste of electric energy;
3. the coal mill is frequently started and stopped, so that the impact of a transmission part is serious, and a large gear, a small gear and a speed reducer are easily damaged;
4. because the starting current is large, the mill needs to be evacuated as far as possible when the mill is stopped, the coal-carrying zero-rotation-speed start cannot be realized, and further abrasion and electric energy waste are caused.
SUMMERY OF THE UTILITY MODEL
In view of the above analysis, and in view of the shortcomings in the prior art, an object of the present invention is to provide a coal pulverizer for thermal power generation, which aims to solve at least one of the above technical problems.
The embodiment of the utility model provides a coal mill for thermal power generation, which comprises: a drum and a drive device;
the driving device is used for driving the roller to rotate;
the driving device includes: a first motor and a second motor; the first motor and the second motor are respectively arranged on two sides of the roller.
Further, still include the converter, the converter sets up on drive arrangement.
Further, the number of the frequency converters is two, one frequency converter is arranged on the first motor, and the other frequency converter is arranged on the second motor.
Further, the first motor and the second motor are the same in type.
Further, the first motor and the second motor are both permanent magnet direct drive motors.
Further, the first motor and the second motor are symmetrically arranged on two sides of the roller.
Further, the driving device further includes: a first gear arrangement and a first coupling;
the first motor is connected with one side of the roller through the first gear device and the first coupling.
Further, the driving device further includes: a second gear arrangement and a second coupling;
the second motor is connected to the other side of the drum through the second gear device and the second coupling.
Further, the load power of the driving device is 1200kw-1300 kw.
Further, the motor input power of the driving device is 1300kw-1400 kw.
Compared with the prior art, the utility model can realize at least one of the following beneficial effects:
1. the permanent magnet motor is used for replacing the traditional structure of an asynchronous motor and a speed reducer, and the speed reducer is not needed, so that the process is simplified, and the fault caused by frequent starting and stopping of the speed reducer is avoided.
2. The permanent magnet motor is used for replacing the traditional structure of an asynchronous motor and a speed reducer, the rated torque and the output torque are increased, and the problem that the starting current of the asynchronous motor is too large when the coal mill is started is solved, so that the stable operation of the coal mill is ensured.
3. In the prior art, the rotation number of the asynchronous motor cannot be adjusted by the asynchronous motor according to the coal feeding amount of the coal mill and the current coal amount in the roller, so that the steel ball in the roller collides with the inner wall of the roller violently. Through setting up first motor of converter automatic control and second motor speed to it is adjustable to realize the cylinder rotational speed, leads to steel ball and cylinder inner wall to take place apart from the collision with preventing the cylinder suddenly with higher speed.
4. The double-motor driving mode is adopted to increase the output torque, so that the load of each motor is further reduced, the starting current of each motor is reduced, and the stable operation of the coal mill is ensured.
In the utility model, the technical schemes can be combined with each other to realize more preferable combination schemes. Additional features and advantages of the utility model will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the utility model. The objectives and other advantages of the utility model will be realized and attained by the structure particularly pointed out in the written description and drawings.
Drawings
The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the utility model, wherein like reference numerals are used to designate like parts throughout.
Fig. 1 is a schematic structural diagram of a coal pulverizer for thermal power generation according to an embodiment of the present invention.
Description of the drawings:
1-a first motor, 2-a second motor, 3-a first gear device, 4-a second gear device, 5-a first coupler, 6-a second coupler, 7-a frequency converter and 8-a roller.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the utility model.
The coal mill is a machine for crushing and grinding coal briquettes into coal powder, and is an important auxiliary device of a coal powder furnace, currently, the coal mill for power generation uses an asynchronous motor, the driving part of the coal mill is a traditional structure of the asynchronous motor and a speed reducer, the composition of a current transmission system is complex, and the total transmission efficiency is low.
The main working principle of the coal mill is as follows: the raw coal is unloaded from the hopper through the coal feeder and enters the mixing box, is pre-dried by bypass air and falls to the bottom of the separator through the coal dropping pipe, and the coal is sent into the rotating drum by the rotating motion of the spiral conveying device. The coal mill is driven by a main motor to rotate by a speed reducer and an open gear. A certain amount of low-chromium alloy steel balls are arranged in the roller. The steel ball is lifted to a certain height through the rotary motion of the roller, and the steel ball impacts and grinds coal in the free flowing and throwing processes until the coal is ground into coal powder, and then the coal powder is mixed with hot primary air and then sent into a boiler hearth.
In the prior art, a driving device of a coal mill is an asynchronous motor and a speed reducer. Specifically, the method comprises the following steps: the motor comprises a main motor, an auxiliary motor, a main speed reducer and an auxiliary speed reducer. A main motor drives a pinion transmission shaft through a main speed reducer, and a pinion is meshed with a large gear fixed on a mill to drive a roller to rotate. The roller is connected with the main motor sequentially through the auxiliary motor, the auxiliary speed reducer and the manually switched clutch and is used for starting, stopping, overhauling and maintaining the mill.
Based on the working principle and the driving mode, the driving device of the coal mill in the prior art has the following problems:
a) the transmission chain length is as follows: the reliability is poor, the main motor adopts a sliding bearing, an oil station needs to be equipped, and the equipment maintenance amount is large.
b) The transmission efficiency is low: the speed reducer has power loss, the transmission efficiency is about 92 percent, and oil needs to be changed regularly.
c) The grinding efficiency is low: the driving system can not regulate the speed and can not work at the optimal rotating speed according to the changing working conditions such as the ball loading amount, the coal feeding amount and the like; if the speed is regulated by using the hydraulic coupler, part of energy is lost in the hydraulic coupler, and the transmission efficiency and the grinding efficiency are further reduced.
d) Difficulty in starting: the asynchronous motor has large starting current, large impact on a power grid and equipment and conservative mechanical and electrical design.
e) The motor 'big horse pulls a trolley' phenomenon is serious: because the steel ball mill rotary grinding cylinder is internally provided with about 130t of steel balls for grinding and a certain amount of coal for a long time, the rotary grinding cylinder needs to overcome huge static friction force and inertia when being started. In order to meet the requirement of starting shaft power, the power of the matched asynchronous motor reaches 2500 kW. Through the analysis of the operation data of the coal mills of the same type, the shaft power of the coal mill is obviously reduced under the rated working condition, and the actual output shaft power of the motor is about 1760kW which is only about 70 percent of the rated power of the motor. While the high efficiency working area of asynchronous machines is usually in the 85% -95% shaft power range. When the power is operated at lower power, the problems of low efficiency, low power factor, high energy consumption and the like exist, and the working efficiency of the coal-saving device is also obviously reduced along with the reduction of the coal feeding quantity.
In order to solve the above problems, the present invention provides a coal pulverizer, as shown in fig. 1, comprising: the device comprises a first motor 1, a second motor 2, a first gear device 3, a second gear device 4, a first coupling 5, a second coupling 6, a frequency converter 7 and a roller 8. Wherein, drive arrangement includes: the device comprises a first motor 1, a second motor 2, a first gear device 3, a second gear device 4, a first coupling 5, a second coupling 6 and a frequency converter 7.
In the present invention, the first motor 1 is connected to one side of the drum 8 through the first gear device 3 and the first coupling 5. The second motor 2 is connected to the other side of the drum 8 through a second gear device 4 and a second coupling 6. The number of the frequency converters 7 is two, one is arranged on the first motor 1, and the other is arranged on the second motor 2. Because first motor 1 and second motor 2 all are connected with cylinder 8 through the gear, in order to guarantee that cylinder 8 is at the uniform velocity and rotates, need first motor 1 and the parameter identical when second motor 2 moves. Therefore, the first electric machine 1 and the second electric machine 2 are the same in model. In order to overcome the technical problems a) -e), a permanent magnet direct drive motor is selected to replace the combination of an asynchronous motor and a speed reducer, and the first motor 1 and the second motor 2 are both permanent magnet direct drive motors. The permanent magnet direct drive motor has the following characteristics:
(1) high efficiency and energy saving. The transmission efficiency of the permanent magnet driving system is about 93%, and compared with the traditional driving system, the efficiency is improved by 10-15 percentage points.
(2) The starting torque is large and the overload capacity is strong. The starting torque of the permanent magnet direct drive motor used by the permanent magnet direct drive system is 200% of the rated torque, pre-starting is not needed, and the starting current is small.
(3) Avoiding the electric network and the mechanical impact. The system uses frequency conversion starting, can realize slow and uniform speed starting of system transmission, has large starting torque, fast dynamic response and strong overload capacity, avoids the impact of instantaneous large current of motor starting on a power grid and the mechanical impact of torque fluctuation on a transmission system, and reduces the power grid fault and the mechanical fault of the system.
(4) The system is maintenance-free. Because the system does not need the reduction gear, the soft device that rises of machinery, consequently need not to change gear oil in practical application, overhauls the reducing gear box, has practiced thrift use cost, has reduced the maintenance work load, and later maintenance only need only annotate oil for 1 time for the motor bearing every 3 ~ 4 months.
(5) The automation degree is high. The motor directly drives the pinion, the whole system is simple, the occupied area is about 30% of the original driving area, and meanwhile, the reduction of the speed reducer also improves the transmission efficiency.
Specifically, the performance ratio of the permanent magnet direct drive motor and the asynchronous motor is shown in table 1,
TABLE 1 permanent-magnet direct-drive improvement benefit estimation (comparison calculation at the same rotation speed)
As can be seen from table 1, the overall efficiency of the permanent magnet motor is much higher than that of the asynchronous motor, and thus the permanent magnet motor has the characteristic of high efficiency compared to the asynchronous motor. The power of the motor and the output power of the motor are smaller than those of an asynchronous motor, so that the starting current can be reduced, and the power is closer to the actual output shaft power of the motor, thereby avoiding the problem that a trolley is pulled by a large horse. The rotating speed of the permanent magnet motor is adjustable, so that the rotating speed can be adjusted according to the changing working conditions such as the ball loading amount, the coal feeding amount and the like, and the transmission efficiency and the grinding efficiency are improved.
In the embodiment of the utility model, the structure of the double permanent magnet motors is utilized, so that each motor shares a part of the output power of the motor, the output power of each motor is further reduced, and the starting current of each motor is further reduced. The output power of each motor is reduced, so that the power of each motor is closer to the actual output shaft power of the motor, and the problem that a cart is pulled by a cart is avoided.
An embodiment of the present invention further provides a machine set, including: the upper layer combustion system, the middle layer combustion system and the lower layer combustion system;
the upper combustion system includes: boiler, combustor and the coal pulverizer of embodiment of this invention. The middle-layer combustion system and the lower-layer combustion system respectively comprise a boiler, a combustor and a coal mill. However, the coal mill of the middle-layer combustion system and the lower-layer combustion system is not limited in the utility model. In the coal burning process, the coal mills in the middle-layer combustion system and the lower-layer combustion system are operated at full load, so that the situation of starting and stopping for many times can not occur, namely the technical problem provided by the utility model does not exist.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.
Claims (8)
1. A coal pulverizer for thermal power generation, comprising: a drum and a drive device;
the driving device is used for driving the roller to rotate;
the driving device includes: a first motor and a second motor; the first motor and the second motor are respectively arranged on two sides of the roller;
the driving device further includes: a first gear arrangement and a first coupling;
the first motor is connected with one side of the roller through the first gear device and the first coupling;
the driving device further includes: a second gear arrangement and a second coupling;
the second motor is connected to the other side of the drum through the second gear device and the second coupling.
2. The coal pulverizer of claim 1, further comprising a frequency converter disposed on the drive device.
3. The coal pulverizer of claim 2,
the number of the frequency converters is two, one frequency converter is arranged on the first motor, and the other frequency converter is arranged on the second motor.
4. The coal pulverizer of claim 1,
the first motor and the second motor are the same in type.
5. The coal pulverizer of claim 4,
the first motor and the second motor are both permanent magnet direct drive motors.
6. The coal pulverizer of claim 5,
the first motor and the second motor are symmetrically arranged on two sides of the roller.
7. The coal pulverizer of claim 1,
the load power of the driving device is 1200kw-1300 kw.
8. The coal pulverizer of claim 1,
the motor input power of the driving device is 1300kw-1400 kw.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121493900.6U CN216125835U (en) | 2021-07-01 | 2021-07-01 | Coal mill for thermal power generation |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121493900.6U CN216125835U (en) | 2021-07-01 | 2021-07-01 | Coal mill for thermal power generation |
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| CN216125835U true CN216125835U (en) | 2022-03-25 |
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| CN202121493900.6U Active CN216125835U (en) | 2021-07-01 | 2021-07-01 | Coal mill for thermal power generation |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115421526A (en) * | 2022-08-31 | 2022-12-02 | 浙江浙能技术研究院有限公司 | AGC speed-up control method based on variable-speed operation of coal mill |
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2021
- 2021-07-01 CN CN202121493900.6U patent/CN216125835U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115421526A (en) * | 2022-08-31 | 2022-12-02 | 浙江浙能技术研究院有限公司 | AGC speed-up control method based on variable-speed operation of coal mill |
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