Maximum output judging and adjusting device for medium-speed coal mill

Abstract

The utility model provides a maximum output judging and adjusting device for a medium-speed coal mill, and belongs to the field of coal mills. Comprising a current monitoring device, a pulverized coal fineness monitoring device, a differential pressure gauge, an air volume meter, a cold air control valve, a hot air control valve and a dynamic separator, the air volume meter, the cold air control valve and the hot air control valve are installed at an inlet of the coal mill, the pulverized coal fineness monitoring device is installed at an outlet of the coal mill, and the differential pressure gauge is used for measuring the pressure difference between the inlet and the outlet of the coal mill; comprising a hydraulic oil station and a loading force proportional overflow valve, the output end of the hydraulic oil station is connected to the input end of the loading force proportional overflow valve, and the output end of the loading force proportional overflow valve is connected to the coal mill. According to the utility model, monitoring data can be acquired in real time through the current monitoring device, the pulverized coal fineness monitoring device and the differential pressure gauge and whether the coal mill reaches a preset upper limit is judged so as to ensure the operation safety of the coal mill, and the maximum output of the coal mill can be adjusted in real time by adjusting the loading force proportional overflow valve, the dynamic separator and the hot air control valve.

Description

Technical Field

[0001] This utility model relates to the field of coal mill technology for power plant boilers, specifically to a device for judging and adjusting the maximum output of a medium-speed coal mill. Background Technology

[0002] Currently, with the increasing prevalence of electricity spot trading across the country, the flexibility and randomness of generator loads are growing. The rapid fluctuations and unpredictability of unit loads bring a series of challenges to operation and equipment control. For coal-fired turbines, different loads correspond to different coal consumption rates, thus requiring frequent start-ups and shutdowns of the pulverizing system, significantly increasing the workload of operators. To address the surge in workload caused by frequent pulverizer starts and shutdowns, many power plants have implemented automatic start-stop systems for pulverizers, automatically starting and stopping them to save labor costs. In these automatic start-stop systems, upper and lower limits for coal feed rates are set for each pulverizing unit.

[0003] Currently, the actual coal quality burned in coal-fired power plants deviates significantly from the design coal quality, and the blending of coal types is complex. It is impossible to ensure that the same coal mill always grinds the same type of coal. For medium-speed coal mills, the maximum output corresponding to different coal types is not the same. In the existing automatic start-stop system for coal mills, the maximum output of the coal mill is determined by a fixed value, which is prone to errors in determining the maximum output of the coal mill. If the fixed maximum output is greater than the actual output, it is easy to cause the coal mill to be blocked. If the fixed maximum output is less than the actual maximum output, the coal mill may be started when it is not necessary, increasing the start frequency of the coal mill. Utility Model Content

[0004] The technical problem to be solved by this utility model is how to ensure the safe operation of the coal mill while increasing its output.

[0005] To solve the above-mentioned technical problems, this utility model provides the following technical solution: a device for judging and adjusting the maximum output of a medium-speed coal mill, characterized in that it includes a current monitoring device, a coal powder fineness monitoring device, a differential pressure gauge, an air volume meter, a cold air regulating valve, a hot air regulating valve, and a dynamic separator, a hydraulic oil station, and a hydraulic oil station load force proportional relief valve located inside the coal mill. The air volume meter, the cold air regulating valve, and the hot air regulating valve are installed at the inlet of the coal mill, the coal powder fineness monitoring device is installed at the outlet of the coal mill, the output end of the hydraulic oil station is connected to the input end of the hydraulic oil station load force proportional relief valve, and the output end of the hydraulic oil station load force proportional relief valve is connected to the coal mill.

[0006] This invention utilizes a differential pressure gauge to measure the pressure difference between the inlet and outlet of the coal mill in real time, a current monitoring device to monitor the current in real time, and a coal powder fineness monitoring device to monitor the coal powder fineness in real time. When any one of the three real-time monitoring data exceeds the preset upper limit, it is determined that the coal mill output has reached the upper limit, and the system can feed back the coal quantity prohibition command to the coal feeder to ensure the safe operation of the coal mill. This invention can also achieve the effect of adjusting the maximum output of the coal mill in real time by adjusting the loading force offset of the hydraulic oil station loading force proportional overflow valve, the air volume offset of the hot air regulating valve, and the frequency of the dynamic separator.

[0007] Preferably, the device for judging and adjusting the maximum output of the medium-speed coal mill also includes a vibration monitoring device installed on the coal mill.

[0008] Preferably, the pressure offset set by the proportional relief valve of the hydraulic oil station does not exceed 1 MPa.

[0009] Preferably, the maximum output judgment and adjustment device for the medium-speed coal mill further includes a hydraulic oil station reaction force proportional relief valve, wherein the input end of the hydraulic oil station reaction force proportional relief valve is connected to the output end of the hydraulic oil station, and the output end of the hydraulic oil station reaction force proportional relief valve is connected to the coal mill.

[0010] Preferably, the dynamic separator is located at the outlet inside the coal mill.

[0011] Preferably, the dynamic separation frequency of the dynamic separator is not less than 30Hz.

[0012] Preferably, the input end of the air volume meter is connected to the output ends of the cold air damper and the hot air damper, and the output end of the air volume meter is connected to the inlet of the coal mill.

[0013] Preferably, the airflow offset set by the hot air damper does not exceed 10 tons per hour.

[0014] Preferably, there are four coal powder fineness monitoring devices.

[0015] The present invention uses several coal powder fineness monitoring devices, and takes the average value of the coal powder fineness monitoring data of several coal powder fineness monitoring devices, so that the monitoring results are more accurate. When the real-time coal powder fineness monitoring data exceeds the preset upper limit, it is determined that the output of the coal mill has reached the upper limit, and the system feeds back the coal quantity prohibition instruction to the coal feeder to ensure the safe operation of the coal mill.

[0016] Preferably, the multiple coal powder fineness monitoring devices are installed side by side at the outlet of the coal mill.

[0017] Compared to existing technologies, the advantages of this invention are as follows: By utilizing a current monitoring device, a coal powder fineness monitoring device, and a differential pressure gauge installed on the coal mill, the current, coal powder fineness, and differential pressure of the coal mill can be monitored in real time to determine whether the coal mill has reached its maximum stress. This is applicable to medium-speed coal mill systems with varying coal qualities, replacing the operation control mode that limits the maximum output to a fixed value. It dynamically judges the maximum stress of the coal mill based on its actual operating conditions, effectively avoiding errors in determining the maximum output. Furthermore, this invention can adjust the maximum output of the coal mill in real time by adjusting the load force offset of the hydraulic oil station's proportional overflow valve, the airflow offset of the hot air damper, and the frequency of the dynamic separator when any one of the three real-time monitored values ​​reaches a preset upper limit. This allows for timely intervention and adjustment when the coal mill experiences blockage, excessive coal powder fineness, or excessive vibration, effectively increasing the output of the coal mill while ensuring its operational safety. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present utility model;

[0019] Figure 2 This is a flowchart for determining the maximum output of the coal mill in an embodiment of this utility model;

[0020] Figure 3 This is a flowchart illustrating the adjustment of the maximum output of the coal mill in this embodiment of the present invention;

[0021] Figure 1 In the diagram, 1 is a coal mill, 2 is a dynamic separator, 3, 4, 5, and 6 are coal powder fineness monitoring devices, 7 is a differential pressure gauge, 8 is an air volume meter, 9 is a cold air control valve, 10 is a hot air control valve, 11 is a hydraulic oil station loading force proportional relief valve, 12 is a hydraulic oil station reaction force proportional relief valve, and 13 is a hydraulic oil station. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0023] Example

[0024] like Figure 1As shown, this embodiment provides a device for judging and adjusting the maximum output of a medium-speed coal mill, including coal powder fineness monitoring devices 3, 4, 5, and 6 installed on the coal mill 1, a differential pressure gauge 7, an air volume meter 8, a cold air regulating valve 9, a hot air regulating valve 10, a coal mill hydraulic oil station 13, a coal mill hydraulic oil station loading force proportional overflow valve 11, a coal mill hydraulic oil station reaction force proportional overflow valve 12, a dynamic separator 2 located inside the coal mill, a real-time current monitoring device, and a vibration monitoring device (not shown in the figure).

[0025] In this embodiment, the four coal powder fineness monitoring devices are located at the outlet of the coal mill 1 and arranged side by side. The two ends of the air volume meter 8 are respectively connected to the output ends of the cold air damper 9 and the hot air damper 10 and the inlet of the coal mill 1. The differential pressure meter 7 is used to monitor the pressure difference between the inlet and outlet of the coal mill 1. The input ends of the proportional overflow valve 11 and the proportional overflow valve 12 of the coal mill hydraulic oil station are connected to the hydraulic oil station 13, and the output ends are connected to the coal mill 1.

[0026] During the operation of a coal mill, as the output of the mill increases, the current also increases, the inlet and outlet differential pressures increase, and the inlet air volume also needs to increase accordingly. To ensure the safe operation of the coal mill, limits are set on relevant parameters during operation, with upper limits set for the differential pressure, current, and fineness of the coal powder.

[0027] like Figure 2 The diagram illustrates the specific process for determining the maximum output of the coal mill in this embodiment:

[0028] The preset upper limits for differential pressure, current, and coal powder fineness of the coal mill are set. Coal powder fineness monitoring devices 3, 4, 5, and 6, differential pressure gauge 7, and current real-time monitoring device monitor the coal mill 1 in real time. In this embodiment, the average value of the real-time monitoring data of coal powder fineness monitoring devices 3, 4, 5, and 6 is taken as the coal powder fineness monitoring data.

[0029] When any one of the real-time monitoring data of coal powder fineness monitoring data, differential pressure gauge 7 and current real-time monitoring device reaches its preset upper limit, it is determined that the output of coal mill 1 has reached the upper limit. At this time, the system issues a coal quantity prohibition command to the coal feeder.

[0030] When any of the real-time monitoring data of the coal powder fineness monitoring data, differential pressure gauge 7, and current real-time monitoring device exceeds its preset upper limit, it is determined that the output of the coal mill 1 has exceeded the upper limit. At this time, the system issues a coal reduction command to the coal feeder. In this embodiment, the specific coal reduction command is to reduce the coal feed rate by 1 t / h, that is, to reduce the coal feed rate by one ton per hour.

[0031] like Figure 3 As shown, in addition to determining whether the output of the coal mill has reached its upper limit, the device in this embodiment also has the function of output adjustment, specifically:

[0032] Alarm values ​​for differential pressure, vibration frequency, and coal powder fineness of the coal mill are set. In this embodiment, the alarm values ​​for differential pressure and coal powder fineness of the coal mill are slightly lower than the preset upper limit values ​​when judging the maximum output of the coal mill.

[0033] When the monitoring data of the coal mill vibration monitoring device is less than its preset alarm value, the system controls the pressure setting value of the proportional relief valve 11 of the coal mill hydraulic oil station to be offset by +0.2MPa. In this embodiment, the maximum offset does not exceed 1MPa.

[0034] When the real-time monitoring data of differential pressure gauge 7 reaches its alarm value, while the coal powder fineness monitoring data does not reach its alarm value, the system issues an instruction to reduce the frequency of the dynamic separator by 1Hz. In this embodiment, the minimum frequency of the dynamic separator 2 is not lower than 30Hz, and the air volume offset set by the hot air damper 10 is increased by 2t / h. In this embodiment, the maximum offset is not more than 10t / h, until the differential pressure of the coal mill drops below the alarm value.

[0035] When the coal powder fineness monitoring data reaches its alarm value, but the real-time monitoring data of the differential pressure gauge 7 does not reach its alarm value, the system issues an instruction to increase the frequency of the dynamic separator by 1Hz and reduce the air volume offset set by the hot air damper 10 by 2t / h. In this embodiment, the maximum offset is not lower than -10t / h, until the coal powder fineness monitoring data drops below the alarm value.

[0036] This embodiment establishes a maximum output judgment system for a medium-speed coal mill. This system uses parameters such as differential pressure, coal powder fineness, and mill current to determine whether the mill's real-time operating status has reached its maximum allowable output. This allows for real-time judgment of the mill's maximum allowable output when the type of coal being ground or other conditions change, ensuring accurate assessment. When the mill output exceeds the upper limits of differential pressure, current, or coal powder fineness, the coal feed rate is automatically reduced to ensure safe operation. Based on the output judgment system, a mill output adjustment system is added to dynamically adjust the limiting factors for continued output, thereby adjusting the upper limit of the mill's maximum allowable output.

[0037] The above-disclosed embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of protection of the present utility model. Therefore, any equivalent changes made in accordance with the claims of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A device for judging and adjusting the maximum output of a medium-speed coal mill, characterized in that, The device comprises a current monitoring device, a coal fineness monitoring device, a differential pressure gauge, a wind volume gauge, a cold air damper, a hot air damper, a dynamic separator, a hydraulic oil station and a hydraulic oil station load force proportional overflow valve installed in the mill.

2. A maximum output judging and adjusting device for a medium speed coal mill according to claim 1, characterized in that, The medium-speed mill maximum output judgment and adjustment device further comprises a vibration monitoring device installed on the mill.

3. The maximum output judging and adjusting device for a medium speed coal mill according to claim 1, characterized in that, The hydraulic oil station load force proportional overflow valve is set to a pressure bias of not more than 1 MPa.

4. The maximum output judging and adjusting device for a medium speed coal mill according to claim 1, characterized in that, The medium-speed mill maximum output judgment and adjustment device further comprises a hydraulic oil station reaction force proportional overflow valve, an input end of the hydraulic oil station reaction force proportional overflow valve being connected to an output end of the hydraulic oil station, and an output end of the hydraulic oil station reaction force proportional overflow valve being connected to the mill.

5. The maximum output judging and adjusting device for a medium speed coal mill according to claim 1, characterized in that, The dynamic separator is located at the outlet of the mill.

6. A maximum output judging and adjusting device for a medium speed coal mill according to claim 5, characterized in that, The dynamic separation frequency of the dynamic separator is not less than 30 Hz.

7. The maximum output judging and adjusting device for a medium speed coal mill according to claim 1, characterized in that, An input end of the wind volume gauge is connected to output ends of the cold air damper and the hot air damper, and an output end of the wind volume gauge is connected to the inlet of the mill.

8. The maximum output judging and adjusting device for a medium speed coal mill according to claim 7, characterized in that, The hot air damper is set to a wind volume bias of not more than 10 tons per hour.

9. The maximum output judging and adjusting device for a medium speed coal mill according to claim 1, characterized in that, The coal fineness monitoring device is four.

10. The maximum output judging and adjusting device for a medium speed coal mill according to claim 9, characterized in that, The multiple coal fineness monitoring devices are installed side by side at the outlet of the mill.

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