Automatic purging method and purging device for measuring wind speed at outlet of coal mill

Abstract

The invention relates to the technical field of coal mills, in particular to an automatic purging method and device for coal mill outlet wind speed measurement, and the method comprises the steps that a coal mill in a unit is started to operate, a wind speed measurement device arranged on a coal mill outlet pipe is also started to operate, and the wind speed measurement device sends data detected in real time to a DCS controller; from the wind speed of the coal mill, the interior of the sampling pipe is purged through high-pressure gas in the gas tank, pulverized coal on the surface of the wind speed measuring instrument on the surface of the sampling pipe is removed, and the surface of the wind speed measuring instrument after purging is clean, so that the accuracy of measuring the wind speed of the outlet pipe of the coal mill is ensured, the labor intensity of maintenance personnel is reduced, and stable operation of a unit is ensured; the third electromagnetic valve is closed during purging, gas is prevented from entering the outlet pipe of the coal mill, and the purged gas enters the bag-type dust collector to be filtered, so that the phenomenon that the flammable risk is increased due to the fact that pulverized coal is discharged into the air is avoided, and meanwhile, the pulverized coal is collected to facilitate subsequent recycling.

Description

Technical Field

[0001] The invention relates to the field of coal mills, in particular to an automatic purge method and a purge device for measuring wind speed at a coal mill outlet. Background Art

[0002] During actual operation, it is very necessary to accurately measure the main parameters that affect the boiler combustion conditions, and then purposefully, systematically and precisely control and adjust the combustion, and find and establish the best combustion conditions. Since the pulverized coal suspension combustion is based on the combustion chemical reaction mode of solid particles in a macroscopic gaseous flow field, the key adjustment item in the combustion adjustment is to first ensure that the boiler mill outlet wind speed and air volume are evenly and reasonably matched, and to establish good aerodynamic conditions in the furnace. Accurate and reliable measurement of the outlet wind speed is to establish a reasonable aerodynamic field inside the furnace, reduce the maximum combustion temperature of the furnace, and effectively control the amount of NO2 generated. It is the basis for ensuring the safety and economy of boiler combustion and achieving boiler combustion optimization.

[0003] As for the wind speed at the outlet of the coal mill, too low wind speed can easily cause pipe blockage, flow interruption, flameout and explosion, and serious wear of the air supply pipe. Uneven wind speed can easily cause the displacement of the combustion center, local coking, boiler explosion and leakage, etc. Therefore, it is necessary to monitor the outlet wind speed.

[0004] At present, the outlet wind speed of the coal mill is generally measured by differential pressure sampling. The outlet wind speed is measured by the characteristic that the pressure difference between the windward and leeward sides increases with the increase of flow velocity. Since there is a large amount of coal powder in the coal mill, it is very easy to clog the sampling tube. Although various manufacturers have made anti-clogging treatments on their products, the effect is not obvious. Especially when the coal type changes, the blockage is more obvious. In serious cases, the pipeline must be purged twice a day before it can be put into normal use, which greatly affects the operating personnel's monitoring of the coal mill operating status and increases the labor intensity of maintenance personnel. In serious cases, untimely adjustment may cause local fire extinguishing of the boiler, affecting the safe and stable operation of the unit. Therefore, an automatic purging method and purging device for measuring the outlet wind speed of the coal mill are proposed to solve the above problems. Summary of the Invention

[0005] The present invention aims to provide an automatic purge method for measuring wind speed at the outlet of a coal mill, which aims to solve the problem that coal powder at the outlet of the coal mill causes blockage of a pressure differential wind speed sampler, thereby affecting the wind speed measurement result.

[0006] The present invention proposes the following technical solution: an automatic purge method for measuring the wind speed at the outlet of a coal mill, which comprises:

[0007] Monitor all coal mill outlet pipes in the unit to obtain multiple sets of wind speed information;

[0008] Transmitting multiple sets of wind speed information to an information processing module, and determining the difference between the multiple sets of wind speed information by the information processing module;

[0009] A cleaning process is performed on the coal mill whose wind speed information difference is greater than the preset value.

[0010] As a preferred embodiment of the automatic purge method for measuring the wind speed at the coal mill outlet of the present invention: the preset value is 30%.

[0011] As a preferred embodiment of the automatic purge method for measuring the wind speed at the outlet of the coal mill of the present invention: before performing the cleaning work, the cleaning records of the coal mills whose wind speed information difference is greater than the preset value are obtained, and the shutdown process is performed on the coal mills whose cleaning records have wind speed information difference greater than the preset value within 6 hours.

[0012] The beneficial effect of the automatic purging method for measuring the wind speed at the coal mill outlet of the present invention is that by measuring the wind speed at the air outlet and purging the wind speed measuring device when the wind speed drops, the wind speed measuring device is ensured not to be blocked by coal powder, thereby ensuring the accuracy of the wind speed measuring device.

[0013] Another object of the present invention is to provide a purging device, which aims to solve the problem of how to purge the wind speed measuring device.

[0014] In order to solve the above technical problems, the present invention also provides the following technical solutions: a purge device, applied to an automatic purge method for measuring wind speed at the outlet of a coal mill; and

[0015] An air velocity measuring device connected to the coal mill outlet pipe; and,

[0016] A purge structure connected to a wind speed measuring device.

[0017] As a preferred embodiment of the purging device of the present invention, the wind speed measuring device includes a sampling tube and a wind speed sensor, the purging structure includes a gas tank, one end of the sampling tube is connected to a bag dust collector through a pipeline, and the other end of the sampling tube is connected to a coal mill outlet pipe through a pipeline.

[0018] As a preferred solution of the purging device of the present invention, a No. 2 solenoid valve is connected to the pipeline between the sampling tube and the bag filter.

[0019] As a preferred solution of the purging device of the present invention, the surface of the sampling tube is connected to a gas tank via a pipeline, and a No. 1 solenoid valve is connected in the pipeline between the sampling tube and the gas tank.

[0020] As a preferred solution of the purging device of the present invention, a No. 3 solenoid valve is connected to the pipeline between the sampling tube and the coal mill outlet pipe.

[0021] As a preferred solution of the purging device of the present invention, the gas tank is connected to the air intake pump through a pipeline.

[0022] As a preferred embodiment of the purging device of the present invention, nitrogen is provided inside the gas tank.

[0023] The beneficial effect of the purging device of the present invention is that the inside of the sampling tube is purged by the high-pressure gas inside the gas tank to remove the coal powder on the surface of the wind speed measuring instrument on the surface of the sampling tube. The surface of the wind speed measuring instrument is clean after purging, thereby ensuring the accuracy of the wind speed measurement of the mill outlet pipe, reducing the labor intensity of maintenance personnel, and ensuring stable operation of the unit. During purging, the No. 3 solenoid valve is closed to prevent gas from entering the mill outlet pipe. The purged gas enters the bag dust collector for filtration, thereby preventing coal powder from being discharged into the air and increasing the risk of flammability. At the same time, the coal powder is collected for convenient subsequent recycling. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings of the embodiments of the present invention. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Among them:

[0025] Figure 1 Flowchart of the automatic purging method of the present invention.

[0026] Figure 2 It is a schematic diagram of the main structure of the present invention.

[0027] Figure 3 It is a side structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to specific embodiments and the accompanying drawings.

[0029] The terms used in the present invention are those commonly used in the art in view of the functions of the present invention, but these terms may vary according to the intentions of those skilled in the art, precedents, or new technologies in the art. In addition, specific terms may be selected by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the present invention. Therefore, the terms used in the specification should not be understood as simple names, but rather as the meanings of the terms and the overall description of the present invention.

[0030] Example 1, please refer to Figure 1 This embodiment provides an automatic purge method for measuring the wind speed at the outlet of a coal mill, comprising:

[0031] S1, monitor all coal mill outlet pipes 4 in the unit to obtain multiple sets of wind speed information;

[0032] There may be multiple coal mills in the same unit, and each coal mill has an outlet pipe. During monitoring, it is necessary to monitor the wind speed information of each coal mill outlet pipe 4 and obtain multiple sets of independent wind speed information.

[0033] When measuring wind speed information, a wind speed measuring device can be used. It should be noted that in the same unit, a wind speed measuring device needs to be independently installed inside the outlet pipe 4 of each coal mill to monitor the wind speed, so as to obtain the wind speed information of the outlet pipe 4 of each coal mill.

[0034] S2. transmitting the multiple sets of wind speed information to an information processing module, and determining the difference between the multiple sets of wind speed information by the information processing module;

[0035] Among them, the information processing module can adopt a DCS controller. The wind speed information of multiple coal mills in the same unit is transmitted to the DCS controller, and the wind speed information of these coal mills is compared and processed by the DCS controller. When performing the comparison processing, the coal mill with wind speed information lower than other wind speed information is mainly selected.

[0036] The difference between the multiple sets of wind speed information determined by the information processing module is the difference between the obviously too low wind speed information and the normal wind speed information detected by the DCS controller. The difference refers to the ratio of the difference between the obviously too low wind speed information and the normal wind speed information to the normal wind speed information. The calculation method is:

[0037]

[0038] Where n is the difference, v1 is the normal wind speed information, and v2 is the low wind speed information;

[0039] Taking the medium-speed coal mill unit processing anthracite as an example, the normal range of the wind speed of the outlet pipe 4 of the coal mill is 25 to 35 m / s. In the same unit, because the working environment and parameters are basically the same, the wind speed of the coal mill is basically the same under normal operation. When a pipe blockage occurs, the wind speed information of the blocked coal mill will be significantly lower than the wind speed of the coal mill in the same unit.

[0040] Under this working condition, assuming that the normal wind speed information collected is 28 m / s and the abnormally low wind speed information is 14 m / s, then n is 50%.

[0041] S3. Perform a cleaning process on the coal mill whose wind speed information difference is greater than a preset value.

[0042] The preset value is 30%. When n obtained in S2 is greater than 30%, it is determined that the wind speed of the outlet pipe 4 of this coal mill is too low. At this time, a cleaning process is performed. The cleaning process is completed by a purge device to solve the pipe blockage problem of the coal mill.

[0043] When performing the cleaning process, the sampling tubes 1 of the coal mill are purged in sequence, and each sampling tube 1 is purged for 30 seconds.

[0044] Example 2. In this embodiment, before executing the cleaning process, the cleaning records of the coal mills whose wind speed information difference is greater than the preset value are obtained, and the shutdown process is executed for the coal mills that have cleaning records within 6 hours and whose wind speed information difference is greater than the preset value.

[0045] After each cleaning process is executed, a record of the cleaning process is made, mainly recording the coal mill that executes the cleaning process and the execution time of the cleaning process, thereby forming a cleaning record. When the wind speed information of one of the coal mills is abnormal and the wind speed information difference is greater than the preset value, the cleaning record is first queried to determine whether the coal mill has executed the cleaning process within 6 hours. If the cleaning process has not been executed within 6 hours, it is determined to be normal and the cleaning process continues to be executed. If the cleaning process has been executed within 6 hours, it is determined that the coal mill has a fault and the shutdown process is executed to shut down the coal mill.

[0046] Example 3, reference Figures 1 to 3 , which is the third embodiment of the present invention, further provides a purge device, an automatic purge method for measuring the wind speed at the outlet of a coal mill, and,

[0047] An air velocity measuring device connected to the coal mill outlet pipe 4; and

[0048] A purge structure connected to a wind speed measuring device.

[0049] If the wind speed measuring device is directly connected to the coal mill outlet pipe 4, the wind speed measuring device can measure the wind speed data of the coal mill outlet pipe 4. However, when the internal air of the coal mill outlet pipe 4 flows, coal powder will be carried out, and the coal powder will accumulate on the surface of the wind speed measuring device. The wind speed measuring device is purged by the purge structure to remove the coal powder on the surface of the wind speed measuring device, thereby ensuring that the data measured by the wind speed measuring device is accurate.

[0050] The wind speed measuring device includes a sampling tube 1 and a wind speed sensor 8, and the purge structure includes an air tank 6. One end of the sampling tube 1 is connected to a bag dust collector 3 through a pipeline, and the other end of the sampling tube 1 is connected to a coal mill outlet pipe 4 through a pipeline.

[0051] The wind speed sensor 8 is fixed inside the sampling tube 1. When the surface of the wind speed sensor 8 is contaminated with too much coal powder, the gas inside the gas tank 6 is used to blow air into the inside of the sampling tube 1. The gas is blown onto the surface of the wind speed sensor 8, thereby blowing off the coal powder on the surface of the wind speed sensor 8, ensuring accurate measurement of the wind speed sensor 8.

[0052] A No. 2 solenoid valve 2 is connected to the pipeline between the sampling tube 1 and the bag filter 3 .

[0053] The No. 2 solenoid valve 2 can connect and disconnect the sampling tube 1 and the bag dust collector 3 to prevent the gas inside the coal mill outlet pipe 4 from entering the sampling tube 1 and then entering the bag dust collector 3 along the pipeline, thereby affecting the results of the wind speed measurement device.

[0054] The surface of the sampling tube 1 is connected to a gas tank 6 via a pipeline, and a first solenoid valve 7 is connected in the pipeline between the sampling tube 1 and the gas tank 6 .

[0055] The No. 1 solenoid valve 7 can connect and disconnect the sampling tube 1 and the gas tank 6 to prevent the gas inside the gas tank 6 from entering the sampling tube 1 and the high-pressure gas in the gas tank 6 from affecting the result of the wind speed measuring device.

[0056] A No. 3 solenoid valve 5 is connected to the pipeline between the sampling tube 1 and the coal mill outlet pipe 4 .

[0057] The No. 3 solenoid valve 5 can connect and disconnect the sampling tube 1 and the coal mill outlet pipe 4, ensuring that the gas inside the gas tank 6 will not enter the coal mill outlet pipe 4 during purging, and at the same time ensuring that the gas can only enter the sampling tube 1 from the gas tank 6 and then enter the bag filter 3, ensuring a single channel for the gas, thereby ensuring the gas flow rate and increasing the purging effect.

[0058] The gas tank 6 is connected to the air intake pump through a pipeline.

[0059] The air intake pump can replenish gas from the outside to the inside of the gas tank 6 to ensure the gas pressure inside the gas tank 6, thereby increasing the purging effect on the sampling tube 1 during purging.

[0060] Nitrogen gas is provided inside the gas tank 6 .

[0061] Nitrogen is a non-flammable gas and cannot be used as an oxidant to assist combustion. Therefore, when nitrogen enters the sampling tube 1 and is directly mixed with the pulverized coal, it will not increase the risk of explosion, thereby ensuring the stability of the purge process.

[0062] Usage process: When purging is required, the No. 3 solenoid valve 5 is closed, and the No. 1 solenoid valve 7 and the No. 2 solenoid valve 2 are opened. The nitrogen inside the gas tank 6 enters the sampling tube 1 through the No. 1 solenoid valve 7, and the pulverized coal in the sampling tube 1 is blown along the pipeline through the No. 2 solenoid valve 2 and enters the bag-type dust collector 3. The filtered nitrogen is discharged and the pulverized coal is left inside the bag-type dust collector 3. At this time, the inside of the sampling tube 1 is cleaned. At this time, the No. 1 solenoid valve 7 and the No. 2 solenoid valve 2 are closed, and the No. 3 solenoid valve 5 is opened. The gas inside the pulverizer outlet pipe 4 enters the sampling tube 1 along the No. 3 solenoid valve 5, and the wind speed sensor 8 connected to the sampling tube 1 measures the wind speed.

[0063] Finally, it should be pointed out that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways without departing from the scope of the present invention.

Claims

1. An automatic purge method for measuring wind speed at a coal mill outlet, characterized by: include, Monitor all coal mill outlet pipes in the unit to obtain multiple sets of wind speed information; Transmitting multiple sets of wind speed information to an information processing module, and determining the difference between the multiple sets of wind speed information by the information processing module; For the coal mill whose wind speed information difference is greater than the preset value, the corresponding purge device is turned on.

2. The automatic purge method for measuring wind speed at a coal mill outlet according to claim 1, characterized in that: The preset value is 30%.

3. The automatic purge method for measuring wind speed at a coal mill outlet according to claim 1, characterized in that: Before performing the cleaning work, obtain the cleaning records of the coal mills whose wind speed information difference is greater than the preset value, and perform the shutdown process for the coal mills whose cleaning records have wind speed information difference greater than the preset value within 6 hours.

4. A purge device, characterized in that: An automatic purge method for measuring wind speed at the coal mill outlet as claimed in any one of claims 1 to 3; and a wind speed measuring device connected to the coal mill outlet pipe (4); and A purge structure connected to a wind speed measuring device.

5. The purging device according to claim 4, characterized in that: The wind speed measuring device comprises a sampling tube (1) and a wind speed sensor (8); the purge structure comprises a gas tank (6); one end of the sampling tube (1) is connected to a bag dust collector (3) via a pipeline; and the other end of the sampling tube (1) is connected to a coal mill outlet pipe (4) via a pipeline.

6. The purging device according to claim 5, characterized in that: A second electromagnetic valve (2) is connected to the pipeline between the sampling tube (1) and the bag dust collector (3).

7. The purging device according to claim 6, characterized in that: The surface of the sampling tube (1) is connected to a gas tank (6) via a pipeline, and a first electromagnetic valve (7) is connected to the pipeline between the sampling tube (1) and the gas tank (6).

8. The purging device according to claim 7, characterized in that: A No. 3 electromagnetic valve (5) is connected to the pipeline between the sampling tube (1) and the coal mill outlet pipe (4).

9. The purging device according to claim 8, characterized in that: The gas tank (6) is connected to the air intake pump via a pipeline.

10. The purging device according to claim 9, characterized in that: Nitrogen is provided inside the gas tank (6).

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