Coal mill purging method, device and system and storage medium

Abstract

The invention discloses a method, a device and a system for purging a coal mill and a storage medium. The method, the device and the system are used for purging the coal mill. The method comprises the following steps: when the coal mill meets a purging condition, determining the type of steam for purging according to coal type information of residual coal powder of the coal mill; injecting the corresponding type of purging steam into the coal mill; detecting whether the type of the injected steam and the steam pressure are qualified or not; when the steam type and the steam pressure are both qualified, whether the steam flow meets the minimum blowing steam flow requirement or not is judged; when the steam flow meets the minimum blowing steam flow requirement, the blowing duration is timed; the internal pressure of the coal mill is monitored, and the steam pressure is adjusted according to the internal pressure of the coal mill, so that the internal pressure of the coal mill rises at a specific speed; when the timed purging duration reaches a preset duration, the oxygen content in the coal mill is monitored; and when the oxygen content in the coal mill is lower than the preset content, it is determined that purging succeeds. According to the invention, the purging effect can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of safety protection of a pulverizing system in a thermal power plant, and in particular to a coal mill purge method, device, system and storage medium. Background Art

[0002] Performing fire-fighting steam purging after a medium-speed coal mill shutdown or before restart is crucial for the safe operation of a thermal power plant's pulverizing system. During an abnormal shutdown and high mill temperatures, the pulverized coal presents a risk of spontaneous combustion and explosion. The use of fire-fighting steam can reduce the temperature and prevent spontaneous combustion, protecting equipment and preventing unsafe events.

[0003] Existing technologies often use fixed purge time patterns, which can easily lead to over- or under-purge under varying operating conditions caused by different coal types. Furthermore, the success of the purge is often judged solely based on whether the internal pressure of the mill rises, ignoring key parameters such as oxygen concentration, which can easily lead to misjudgment.

[0004] Therefore, how to provide a coal mill purging method to improve the purging effect and ensure the safety of equipment and personnel. Summary of the Invention

[0005] The present application provides a coal mill purging method, device, system and storage medium to improve the purging effect and ensure the safety of equipment and personnel.

[0006] The present application provides a coal mill purging method, comprising:

[0007] When the coal mill meets the purging conditions, determining the type of steam used to purge the coal mill according to the coal type information of the residual coal powder in the coal mill;

[0008] injecting the corresponding type of purge steam into the coal mill;

[0009] Check whether the type and pressure of injected steam are qualified;

[0010] When the steam type and steam pressure are qualified, determine whether the steam flow meets the minimum purge steam flow requirement;

[0011] When the steam flow rate meets the minimum purge steam flow rate requirement, the purge time is counted;

[0012] During the purging process, the internal pressure of the coal mill is monitored, and the steam pressure is adjusted according to the internal pressure of the coal mill so that the internal pressure of the coal mill increases at a specific rate;

[0013] When the timed purge time reaches the preset time, the oxygen content inside the coal mill is monitored;

[0014] When the oxygen content inside the coal mill is lower than the preset content, it is determined that the purging is successful.

[0015] The beneficial effects of the present application are as follows: when a coal mill meets the purging conditions, the type of steam used to purge the coal mill is determined based on the coal type information of the residual coal powder in the coal mill to cover special operating conditions such as coal with different volatile contents. Then, the corresponding type of purge steam is injected into the coal mill, and the type and steam pressure of the injected steam are tested to see if they are qualified; when both the steam type and steam pressure are qualified, it is determined whether the steam flow meets the minimum purge steam flow requirement; when the steam flow meets the minimum purge steam flow requirement, the purge duration is timed; during the purge process, the internal pressure of the coal mill is monitored, and the steam pressure is adjusted according to the internal pressure of the coal mill so that the internal pressure of the coal mill increases at a specific rate; when the timed purge duration reaches a preset duration, the oxygen content inside the coal mill is monitored; and when the oxygen content inside the coal mill is lower than the preset content, the purge is determined to be successful. This application improves the purging effect by controlling multiple links such as steam quality, flow calculation, dynamic time monitoring, and pressure control. In addition, through oxygen concentration monitoring, it ensures that the oxygen content in the pulverizer is lower than the preset content and is in the safe oxygen content range, thereby ensuring the safe operation of the system.

[0016] In one embodiment, the detecting whether the type and pressure of the injected steam are qualified includes:

[0017] Obtain the steam pressure and steam inlet temperature of the purge steam;

[0018] Determine whether the steam type is qualified based on the steam pressure and steam inlet temperature;

[0019] Whether the steam pressure is qualified is determined based on the steam pressure threshold and the pressure fluctuation threshold.

[0020] In one embodiment, when it is determined that the type of steam used to purge the coal mill is saturated steam, judging whether the steam type is qualified based on the steam pressure and the steam inlet temperature includes:

[0021] Look up the corresponding saturation temperature table according to the steam pressure to determine the saturation temperature range corresponding to the current steam pressure;

[0022] When the steam temperature is within the saturation temperature range or the steam temperature is higher than the maximum value of the saturation temperature range, the steam type is determined to be qualified;

[0023] When the steam temperature is lower than the minimum value of the saturation temperature range, it indicates that the steam type is unqualified.

[0024] In one embodiment, judging whether the steam pressure is qualified according to the steam pressure threshold and the pressure fluctuation threshold includes:

[0025] When the steam pressure is greater than a preset steam pressure threshold and the pressure fluctuation is less than or equal to a preset pressure fluctuation threshold, it is determined that the steam pressure is qualified.

[0026] In one embodiment, the method further comprises:

[0027] When the steam type and / or steam pressure test fails, it is determined that the purge has failed;

[0028] Close the steam purge valve and be prompted to handle if the steam contains water or the pressure is unstable.

[0029] In one embodiment, the minimum purge steam flow rate is determined as follows:

[0030] The minimum steam quantity required for the coal mill is determined according to the following formula:

[0031]

[0032] Among them, Q steam is the required fire steam mass flow rate; V is the coal mill volume; C0 is the initial oxygen concentration; C1 is the preset oxygen content of the coal mill to meet the purge requirements after the purge is completed; ρ air is the air density; η is the inerting efficiency; t is the preset time for the coal mill to complete the purge; M air is the molar mass of air; M steam is the molar mass of steam.

[0033] In one embodiment, the method further comprises:

[0034] When the steam flow rate is less than the minimum purge steam flow rate, it is determined that the steam flow rate is unqualified, the purge process is exited, the steam purge valve is closed, and a prompt is given that the steam purge flow rate is insufficient and the purge fails.

[0035] In one embodiment, the method further comprises:

[0036] The preset time for the coal mill to complete the purging and the preset oxygen content required for the coal mill to meet the purging requirements after the purging is completed are determined according to the coal type information of the residual coal powder in the coal mill.

[0037] In one embodiment, the method further comprises:

[0038] After successful purging, monitor the internal pressure stability of the coal mill;

[0039] When the rate of decrease of the internal pressure of the coal mill is less than the first rate, it is determined that the coal mill has no leakage;

[0040] When the rate of decrease of the internal pressure of the coal mill is greater than the first rate, it is determined that leakage occurs in the coal mill.

[0041] In one embodiment, the method further comprises:

[0042] When the rate of decrease of the internal pressure of the coal mill is greater than the first rate and less than the second rate, it is determined that the coal mill has a primary leakage, and the steam flow rate is increased and the purge time is extended;

[0043] When the rate of decrease of the internal pressure of the coal mill is greater than or equal to the second rate, the coal mill is determined to have a secondary leak, the purge is determined to have failed, the purge is immediately interrupted, the coal mill is locked and a maintenance alarm is triggered.

[0044] The present application also provides a coal mill purge device, comprising:

[0045] A first determining module is configured to determine the type of steam used to purge the coal mill according to the coal type information of the residual coal powder in the coal mill when the coal mill meets the purge conditions;

[0046] an injection module for injecting the corresponding type of purge steam into the coal mill;

[0047] Detection module, used to detect whether the type and pressure of injected steam are qualified;

[0048] A judgment module is used to judge whether the steam flow meets the minimum purge steam flow requirement when the steam type and steam pressure are qualified;

[0049] A timing module is used to time the purge time when the steam flow rate meets the minimum purge steam flow rate requirement;

[0050] a first monitoring module, configured to monitor the internal pressure of the coal mill during the purging process and adjust the steam pressure according to the internal pressure of the coal mill so that the internal pressure of the coal mill increases at a specific rate;

[0051] The second monitoring module is used to monitor the oxygen content inside the coal mill when the timed purge time reaches a preset time;

[0052] The second determination module is used to determine that the purging is successful when the oxygen content inside the coal mill is lower than a preset content.

[0053] In one embodiment, the detection module includes:

[0054] An acquisition submodule, used for acquiring the steam pressure and steam inlet temperature of the purge steam;

[0055] The first judgment submodule is used to judge whether the steam type is qualified according to the steam pressure and steam inlet temperature;

[0056] The second judgment submodule is used to judge whether the steam pressure is qualified according to the steam pressure threshold and the pressure fluctuation threshold.

[0057] In one embodiment, when it is determined that the type of steam used to purge the coal mill is saturated steam, the first judgment submodule is further configured to:

[0058] Look up the corresponding saturation temperature table according to the steam pressure to determine the saturation temperature range corresponding to the current steam pressure;

[0059] When the steam temperature is within the saturation temperature range or the steam temperature is higher than the maximum value of the saturation temperature range, the steam type is determined to be qualified;

[0060] When the steam temperature is lower than the minimum value of the saturation temperature range, it indicates that the steam type is unqualified.

[0061] In one embodiment, the second judgment submodule is further configured to:

[0062] When the steam pressure is greater than a preset steam pressure threshold and the pressure fluctuation is less than or equal to a preset pressure fluctuation threshold, it is determined that the steam pressure is qualified.

[0063] In one embodiment, the detection module further includes:

[0064] The determination submodule is used to determine that the purge has failed when the steam type and / or steam pressure test fails, close the steam purge valve, and prompt that the steam contains water or the pressure is unstable and requires processing.

[0065] In one embodiment, the minimum purge steam flow rate is determined as follows:

[0066] The minimum steam quantity required for the coal mill is determined according to the following formula:

[0067]

[0068] Among them, Q steam is the required fire steam mass flow rate; V is the coal mill volume; C0 is the initial oxygen concentration; C1 is the preset oxygen content of the coal mill to meet the purge requirements after the purge is completed; ρ air is the air density; η is the inerting efficiency; t is the preset time for the coal mill to complete the purge; M air is the molar mass of air; M steam is the molar mass of steam.

[0069] In one embodiment, the apparatus further comprises:

[0070] The third determination module is used to determine that the steam flow is unqualified when the steam flow is less than the minimum purge steam flow, exit the purge process, close the steam purge valve, and prompt that the steam purge flow is insufficient and the purge fails.

[0071] In one embodiment, the apparatus further comprises:

[0072] The fourth determining module is used to determine the preset time for the coal mill to complete the purge and the preset oxygen content required for the coal mill to meet the purge requirements after the purge is completed according to the coal type information of the residual coal powder in the coal mill.

[0073] In one embodiment, the apparatus further comprises:

[0074] The third monitoring module is used to monitor the internal pressure stability of the coal mill after the purging is successful;

[0075] a fifth determining module, configured to determine that no leakage occurs in the coal mill when the rate of decrease of the internal pressure of the coal mill is less than the first rate;

[0076] The fifth determination module is further configured to determine that leakage occurs in the coal mill when the rate of decrease in the internal pressure of the coal mill is greater than the first rate.

[0077] In one embodiment, the fifth determining module is further configured to:

[0078] When the rate of decrease of the internal pressure of the coal mill is greater than the first rate and less than the second rate, it is determined that the coal mill has a primary leakage, and the steam flow rate is increased and the purge time is extended;

[0079] When the rate of decrease of the internal pressure of the coal mill is greater than or equal to the second rate, the coal mill is determined to have a secondary leak, the purge is determined to have failed, the purge is immediately interrupted, the coal mill is locked and a maintenance alarm is triggered.

[0080] The present application also provides a coal mill purge system, comprising:

[0081] at least one processor; and,

[0082] a memory communicatively connected to the at least one processor; wherein,

[0083] The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to implement the coal mill purging method described in any one of the above embodiments.

[0084] The present application also provides a computer-readable storage medium. When the instructions in the storage medium are executed by a processor corresponding to the coal mill purge system, the coal mill purge system can implement the coal mill purge method described in any of the above embodiments.

[0085] Other features and advantages of the present application will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present application. The purposes and other advantages of the present application can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings.

[0086] The technical solution of the present application is further described in detail below through the accompanying drawings and examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] The accompanying drawings are used to provide a further understanding of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation of the present application. In the accompanying drawings:

[0088] Figure 1 This is a flow chart of a coal mill purging method in one embodiment of the present application;

[0089] Figure 2 This is a structural schematic diagram of a coal mill purge device in one embodiment of the present application;

[0090] Figure 3 This is a hardware structure diagram of a coal mill purge system in one embodiment of the present application. DETAILED DESCRIPTION

[0091] The preferred embodiments of the present application are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present application and are not used to limit the present application.

[0092] Medium-speed coal mills require purging with fire steam after shutdown or before restart, a critical operation for the safe operation of the pulverizing system in a thermal power plant. When a coal mill experiences an abnormal shutdown and the temperature inside the mill remains high, the pulverized coal is very likely to spontaneously combust and explode, causing significant damage to the equipment and posing a safety hazard to personnel. If fire steam is used during an abnormal shutdown, the mill can be cooled while the steam covers the accumulated pulverized coal, preventing its spontaneous combustion. This effectively protects the equipment and prevents unsafe incidents. One of the main purposes of this process is to prevent the explosion of residual pulverized coal in the mill, which could lead to serious consequences. The core purposes of fire-fighting steam purging include: first, inerting and explosion prevention, which displaces the oxygen in the mill through saturated steam, reducing the oxygen concentration to below the preset content (the lower explosion limit of coal powder, for example, 12%), thereby inhibiting spontaneous combustion and deflagration; second, cooling and flame suppression, as steam has a high specific heat capacity and can quickly absorb the heat of accumulated powder in the mill, reducing the temperature from the dangerous zone to a safe range; and removing accumulated powder: the steam flow has a strong carrying capacity and can remove residual coal powder in areas prone to powder accumulation, such as the dead zone of the primary air chamber and the gap between the grinding rollers.

[0093] After a medium-speed coal mill is shut down, it must undergo a fire steam purge. Whether a fire steam purge is required before starting a medium-speed coal mill depends primarily on the duration of the mill's downtime. If the downtime is short (e.g., <8 hours), and the fire steam purge was completed according to procedures and the mill was maintained in an inerted state (oxygen concentration <12%) during the shutdown, re-purging before starting is generally not necessary. After a long shutdown (>48 hours) or maintenance, air may enter the mill, requiring re-purging and inerting. In cases where the normal purge process is not completed during an emergency shutdown due to a fault, resulting in a large amount of residual coal dust, or when using high-volatile coals such as lignite and bituminous coal (volatile matter V > 25%), stricter explosion-proof measures are required, and pre-start purging is recommended. Therefore, it is necessary to first check whether the necessary steam purge has been carried out, and secondly, to ensure that the purge is qualified. Whether a purge has been carried out is relatively easy to determine. To determine the effectiveness of the steam purge, this application improves the purge effect through multiple aspects of control and monitoring to ensure that the purge is qualified.

[0094] Figure 1 This is a flow chart of a coal mill purging method according to an embodiment of the present application. Figure 1 As shown, the method can be implemented as the following steps S101-S108:

[0095] In step S101, when the coal mill meets the purging conditions, the type of steam used to purge the coal mill is determined according to the coal type information of the residual coal powder in the coal mill;

[0096] In step S102, the corresponding type of purge steam is injected into the coal mill;

[0097] In step S103, the type and pressure of the injected steam are checked to see if they are qualified;

[0098] In step S104, when the steam type and steam pressure are both qualified, it is determined whether the steam flow rate meets the minimum purge steam flow rate requirement;

[0099] In step S105, when the steam flow rate meets the minimum purge steam flow rate requirement, the purge time is counted;

[0100] In step S106, during the purging process, the internal pressure of the coal mill is monitored, and the steam pressure is adjusted according to the internal pressure of the coal mill so that the internal pressure of the coal mill increases at a specific rate;

[0101] In step S107, when the timed purge duration reaches a preset duration, the oxygen content inside the coal mill is monitored;

[0102] In step S108 , when the oxygen content inside the coal mill is lower than a preset content, it is determined that the purging is successful.

[0103] In this application, the grinding system needs to be shut down before purging. Since the coal mill is filled with a mixture of coal powder and air when it is running, and during normal operation, the primary air will continue to provide the coal mill with power to transport coal powder, so that the coal powder is in a flowing and suspended state. If fire steam purging is carried out at this time, a large amount of steam will enter the coal mill, which will cause the mixture of coal powder and air to be strongly disturbed, causing the coal powder to fly and fully mix with the air to form an explosive mixture. Once it encounters a fire source or high temperature, it is very easy to cause an explosion accident. Therefore, before steam purging, the hot primary air damper and the cold primary air damper of the coal mill need to be closed, and the operation of the coal mill needs to be stopped.

[0104] When the pulverizer meets the purging conditions, the type of steam used to purge the pulverizer is determined based on the coal type information of the residual pulverized coal in the pulverizer. Coal type information refers to the classification of coal into anthracite, bituminous coal, and lignite based on indicators such as dry ash-free volatile matter. Bituminous coal can be further divided into lean coal, lean lean coal, lean coal, coking coal, fat coal, 1 / 3 coking coal, gas-fat coal, gas coal, 1 / 2 medium-caking coal, weakly caking coal, non-caking coal, and long-flame coal, among other categories of lignite and bituminous coal. Coal type information can be obtained using a volatile matter detector installed on the coal feeder. Because different types of pulverized coal have different volatile contents and ignition points, for example, lignite has a higher volatile content and a lower ignition point, making it prone to spontaneous combustion or explosion at high temperatures. Using inappropriate steam for purging can cause the pulverized coal temperature to rise, potentially leading to explosions. Therefore, it is necessary to select the appropriate steam type based on the coal type to reduce the temperature and humidity of the pulverized coal and prevent explosions. Specifically, the types of steam used for purging include supersaturated steam and saturated steam, wherein the types of steam required for different types of coal can be predetermined, for example, supersaturated steam is used for lignite and saturated steam is used for other types of coal.

[0105] Then, the corresponding type of purge steam is injected into the coal mill; the injected steam type and steam pressure are tested to determine if they meet the requirements. In this application, the steam pressure and steam temperature of the purge steam are obtained, and the steam type is determined based on the steam pressure and steam inlet temperature. The steam pressure is determined based on the steam pressure threshold and the pressure fluctuation threshold.

[0106] (1) Check whether the steam type is qualified:

[0107] According to the steam pressure, the corresponding saturation temperature table (i.e., water vapor table) is searched to determine the saturation temperature range corresponding to the current steam pressure; then, whether the current steam temperature is qualified is determined. Specifically, if the steam temperature is in the saturation temperature range, it is saturated steam; if the steam temperature is higher than the maximum value of the saturation temperature range, it is superheated steam; if the steam temperature is lower than the minimum value of the saturation temperature range, it is unsaturated steam. When the current steam is saturated steam or superheated steam, the steam type is determined to be qualified; of course, in order to ensure the purging effect, the steam temperature can also be continuously observed for one minute. If the qualified steam quality is reached within one minute and remains qualified for 30 seconds, the steam quality is determined to be qualified.

[0108] If the current steam is unsaturated steam, it will prompt that the steam type is unqualified; similarly, in order to ensure the purging effect, you can also continuously observe the steam temperature for one minute when the current steam is unsaturated steam. If it reaches saturated steam or superheated steam within one minute and maintains for 30 seconds, it is judged that the steam type is qualified, otherwise it is unqualified.

[0109] (2) Check whether the steam pressure is qualified.

[0110] Under normal circumstances, the purge pressure needs to be higher than a certain pressure value (such as 0.3Mpa). However, if there are many steam users in the steam manifold, the pressure may be lower during some periods of time. This may cause the steam to be unable to penetrate the coal powder layer and the inerting effect is insufficient. In addition, the purge steam pressure should be relatively stable during the injection process. For example, the absolute value of the pressure fluctuation should be within 0.1MPa. If the pressure drops suddenly or fluctuates frequently, it may indicate that the pipeline is blocked, the valve is leaking, or the steam source is unstable, which seriously affects the purge effect. Therefore, this application pre-sets the steam pressure threshold and the pressure fluctuation threshold. When the steam pressure is greater than the preset steam pressure threshold and the pressure fluctuation is less than or equal to the preset pressure fluctuation threshold, the steam pressure is determined to be qualified. For example, the steam pressure is greater than 0.3MP and the purge steam pressure fluctuation during the process should be ≤±0.1MPa to be qualified. Otherwise, the steam pressure is judged to be unqualified.

[0111] Because different types of coal have varying physical and chemical properties, such as hardness and viscosity, these properties can affect the accumulation and flow characteristics of the coal within the pulverizer, and thus the purging effect. For example, for viscous coal, higher-pressure steam may be required for purging to improve the purging effect. Therefore, in one embodiment of the present application, the steam pressure threshold and pressure fluctuation threshold are pre-set based on the coal type information.

[0112] If the steam type and steam pressure tests are qualified, proceed to the next step. Otherwise, if the steam type and / or steam pressure tests are unqualified, the purge is determined to have failed, the steam purge valve is closed, and a message is displayed indicating that the steam contains water or the pressure is unstable. Please take action.

[0113] When the steam type and steam pressure are qualified, determine whether the steam flow meets the minimum purge steam flow requirement. The fire steam volume of the coal mill should be determined according to the volume of the inerted coal mill to determine the required minimum steam flow, and the fire steam replaces and dilutes the oxygen in the coal mill to reduce the oxygen concentration to within the preset content (i.e., the lower limit of coal powder explosion). Specifically, the preset time for the coal mill to complete the purge and the preset content of oxygen required for the coal mill to reach the purge requirement after the purge is completed are determined based on the coal type information of the residual coal powder in the coal mill. Then, the preset time t for the coal mill to complete the purge and the preset content C1 of oxygen required for the coal mill to reach the purge requirement after the purge is completed are substituted into the following formula to determine the minimum steam volume required for the coal mill to reduce the oxygen content in the coal mill from the initial value C0 to the target value C1:

[0114]

[0115] Among them, Q steam Indicates the required fire steam mass flow rate (kg / h); V indicates the coal mill volume (m 3 ); C0 represents the initial oxygen concentration (e.g., 21%); C1 represents the preset oxygen content required for the pulverizer to achieve the purge requirement after the purge is completed (e.g., 12% for bituminous coal, 10% for high-volatile coal and lignite); ρ air Indicates air density (1.29kg / m 3 , standard state); η represents the inerting efficiency (0.7-0.8); t represents the preset time for the pulverizer to complete the purge (e.g., 10 minutes for conventional, 8 minutes for high-volatile coal, and 5 minutes for lignite); M air Indicates the molar mass of air; M steam Indicates the molar mass of steam.

[0116] When the steam flow meets the minimum purge steam flow requirement, the purge duration is timed. By obtaining the current real-time steam flow, if the steam flow is greater than or equal to the minimum steam purge flow, the purge requirement is met and the steam purge timing begins. If the steam flow is less than the minimum steam purge flow, the purge is determined to have failed, the steam purge valve is closed, and a message indicating insufficient steam purge flow is displayed.

[0117] During the purging process, the internal pressure of the coal mill is monitored and the steam pressure is adjusted accordingly to ensure that the internal pressure rises at a specific rate. The pressure rise rate reflects the dynamic changes in the steam within the coal mill. If the rise rate is too fast, it may cause excessive impact on the internal structure of the coal mill, causing damage to the equipment; if the rise rate is too slow, effective purging may not be achieved. Therefore, the internal pressure of the coal mill should be guaranteed to rise at a specific rate. Specifically, the specific rate can be within a pre-set pressure rise rate range, such as 1 to 3 kPa / min. The specific adjustment process is as follows: the internal pressure of the coal mill is determined by real-time acquisition of the internal pressure of the coal mill; the steam pressure is dynamically adjusted using the PID controller to maintain the internal pressure rise rate within the pre-set pressure rise rate range. Throughout the entire process, the PID controller continuously adjusts the steam flow rate or the opening of the pressure regulating device (such as the regulating valve) based on the deviation between the pre-set specific pressure rise rate and the actual measured pressure rise rate, combined with the PID parameters pre-adjusted according to the coal type characteristics, to achieve precise control of the steam pressure rise rate.

[0118] Among them, PID control is a feedback control algorithm widely used in industrial process control. The three parameters of proportional coefficient (P), integral time (I) and differential time (D) work together to adjust the control output according to the deviation between the set value and the actual measured value. The proportional link adjusts the output proportionally according to the size of the deviation. The larger the deviation, the larger the adjustment amplitude; the integral link is used to eliminate steady-state errors and adjusts the deviation as it accumulates over time; the differential link adjusts according to the rate of change of the deviation and can respond quickly to dynamic changes in the system. In this application, different adjustment parameters are selected according to different coal types. For example, lignite, a coal with a high volatile content, has a relatively low ignition point and is prone to combustion or even explosion. During fire steam purge, it is necessary to control the steam pressure rise rate more quickly and accurately. Using a more aggressive proportional coefficient (larger P value) means that when there is a deviation, the control system will make a larger adjustment, so that the steam pressure rise rate can reach and stabilize at an appropriate value more quickly, thereby more effectively suppressing the fire risk caused by the volatile content of lignite.

[0119] At the same time, this application adds feedforward control and monitors the steam main pressure to predict possible disturbances to the steam pressure inside the coal mill. For example, if the steam main pressure suddenly increases or decreases, this may directly affect the steam pressure entering the coal mill. Through feedforward control, the system can adjust the steam flow rate or other related parameters in advance based on the changing trend of the steam main pressure before the internal pressure of the coal mill is significantly affected, thereby reducing the impact of disturbances on the rate of pressure rise inside the coal mill and ensuring that the pressure can rise according to the pre-set pressure rise rate.

[0120] When the timed purge time reaches the preset time, the oxygen content inside the coal mill is monitored.

[0121] Consistent with the above, the preset time for the coal mill to complete purging and the preset oxygen content required for the coal mill to meet the purging requirements after purging are determined based on the coal type information of the residual coal powder in the coal mill.

[0122] This application determines the preset time for the coal mill to complete the purge based on the coal type information. First, based on the predetermined coal type-purge time correspondence table, the basic purge time of each coal type is queried. For example, the basic purge time of bituminous coal is 10 minutes, the basic purge time of high-volatile coal is 8 minutes, and the basic purge time of lignite is 5 minutes. Then, the current stop state is obtained. When the current stop state is an emergency stop, the preset time for the coal mill to complete the purge is the basic purge time plus the preset time; otherwise, the preset time for the coal mill to complete the purge is determined to be the basic purge time.

[0123] When the purge duration reaches a preset value, the oxygen content within the coal mill is measured. When the oxygen content within the coal mill falls below the preset value, the purge is determined to be successful, and the steam purge valve is closed. In this application, the preset oxygen content after purging for different coal types can be determined based on a preset coal type-oxygen content mapping table. For example, the oxygen content threshold for bituminous coal is 12%, and the oxygen content threshold for high-volatile coal and lignite is 10%. When the oxygen content in the coal mill is greater than or equal to the preset content corresponding to the coal type, it is determined whether it is an emergency stop; when the current stop state is an emergency stop, when the oxygen content of the coal mill is lower than the preset content, the steam purge valve is automatically closed to determine that the purge is successful; when the current stop state is an emergency stop and the purge time reaches the maximum purge time, the steam purge valve is automatically closed, and the re-purge process is restarted after checking that the purge steam system has no faults and the coal mill has no leakage; when it is not an emergency stop, it is determined that the purge has failed, the steam purge valve is closed, and a prompt is given that "the oxygen content does not meet the safety quality assurance, and the steam purge failed."

[0124] In one embodiment of the present application, after the purging is successful, the internal pressure stability of the coal mill is monitored to determine whether there is any leakage in the system. When the purging is successful, the pressure fluctuation amplitude should be within the preset range, for example, the absolute value of the pressure fluctuation is ≤1kPa. If the pressure continues to drop, it indicates that there is a leakage interruption in the system. When the rate of decrease of the internal pressure of the coal mill is less than the first rate, it is determined that the coal mill has no leakage; when the rate of decrease of the internal pressure of the coal mill is greater than the first rate, it is determined that the coal mill has a leakage. Further, when the rate of decrease of the internal pressure of the coal mill is greater than the first rate and less than the second rate, it is determined that the coal mill has a first-level leakage, and the steam flow rate is increased and the purging time is extended. For example, when the rate of decrease is 0.5-1kPa / min, the steam flow rate is increased by 10% and the purging time is extended by 20%; when the rate of decrease of the internal pressure of the coal mill is greater than or equal to the second rate, it is determined that the coal mill has a second-level leakage, for example, when the rate of decrease is greater than 1kPa / min, it is determined that the purging has failed, the purging is immediately interrupted, the coal mill is locked and the maintenance alarm is triggered.

[0125] In one embodiment of the present application, the purging effect can also be judged based on the temperature of the coal mill shell. Since the temperature should tend to be stable after the steam is injected and eventually approach the temperature of the fire steam. In this embodiment, the coal mill shell temperature is obtained; the temperature rise rate is calculated based on the coal mill shell temperature; when the temperature rise rate is less than the preset temperature rise rate value, it indicates that the current coal mill shell temperature is tending to be stable. When the temperature rise rate is less than the preset temperature rise rate value or the purging reaches the preset time, the difference between the current coal mill shell temperature and the steam temperature is calculated; when the difference is greater than the preset temperature threshold, it means that the purging has not cleaned or processed the internal substances to the ideal state, and there are still potential safety hazards. It is determined that the purging has failed and an alarm is issued.

[0126] The beneficial effects of the present application are as follows: when a coal mill meets the purging conditions, the type of steam used to purge the coal mill is determined based on the coal type information of the residual coal powder in the coal mill to cover special operating conditions such as coal with different volatile contents. Then, the corresponding type of purge steam is injected into the coal mill, and the type and steam pressure of the injected steam are tested to see if they are qualified; when both the steam type and steam pressure are qualified, it is determined whether the steam flow meets the minimum purge steam flow requirement; when the steam flow meets the minimum purge steam flow requirement, the purge duration is timed; during the purge process, the internal pressure of the coal mill is monitored, and the steam pressure is adjusted according to the internal pressure of the coal mill so that the internal pressure of the coal mill increases at a specific rate; when the timed purge duration reaches a preset duration, the oxygen content inside the coal mill is monitored; and when the oxygen content inside the coal mill is lower than the preset content, the purge is determined to be successful. This application improves the purging effect by controlling multiple links such as steam quality, flow calculation, dynamic time monitoring, and pressure control. In addition, through oxygen concentration monitoring, it ensures that the oxygen content in the pulverizer is lower than the preset content and is in the safe oxygen content range, thereby ensuring the safe operation of the system.

[0127] In one embodiment, the above step S103 may be implemented as the following steps A1-A3:

[0128] In step A1, the steam pressure and steam inlet temperature of the purge steam are obtained;

[0129] In step A2, the steam type is determined to be qualified based on the steam pressure and steam inlet temperature;

[0130] In step A3, whether the steam pressure is qualified is determined based on the steam pressure threshold and the pressure fluctuation threshold.

[0131] In one embodiment, when it is determined that the type of steam used to purge the coal mill is saturated steam, the above step A2 may be implemented as the following steps A21-A23:

[0132] In step A21, the corresponding saturation temperature table is searched according to the steam pressure to determine the saturation temperature range corresponding to the current steam pressure;

[0133] In step A22, when the steam temperature is within the saturation temperature range or the steam temperature is higher than the maximum value of the saturation temperature range, it is determined that the steam type is qualified;

[0134] In step A23, when the steam temperature is lower than the minimum value of the saturation temperature range, it is prompted that the steam type is unqualified.

[0135] In one embodiment, the above step A3 may be implemented as follows:

[0136] When the steam pressure is greater than a preset steam pressure threshold and the pressure fluctuation is less than or equal to a preset pressure fluctuation threshold, it is determined that the steam pressure is qualified.

[0137] In one embodiment, the method may also be implemented as follows:

[0138] In step A4, when the steam type and / or steam pressure detection fails, it is determined that the purge has failed;

[0139] In step A5, close the steam purge valve and a message will appear indicating that the steam contains water or the pressure is unstable, please handle it.

[0140] In one embodiment, the minimum purge steam flow rate may be determined by the following steps:

[0141] The minimum steam quantity required for the coal mill is determined according to the following formula:

[0142]

[0143] Among them, Q steamis the required fire steam mass flow rate; V is the coal mill volume; C0 is the initial oxygen concentration; C1 is the preset oxygen content of the coal mill to meet the purge requirements after the purge is completed; ρ air is the air density; η is the inerting efficiency; t is the preset time for the coal mill to complete the purge; M air is the molar mass of air; M steam is the molar mass of steam.

[0144] In one embodiment, the method may also be implemented as follows:

[0145] When the steam flow rate is less than the minimum purge steam flow rate, it is determined that the steam flow rate is unqualified, the purge process is exited, the steam purge valve is closed, and a prompt is given that the steam purge flow rate is insufficient and the purge fails.

[0146] In one embodiment, the method may also be implemented as follows:

[0147] The preset time for the coal mill to complete the purging and the preset oxygen content required for the coal mill to meet the purging requirements after the purging is completed are determined according to the coal type information of the residual coal powder in the coal mill.

[0148] In one embodiment, the method may also be implemented as follows:

[0149] In step B1, after the purging is successful, the internal pressure stability of the coal mill is monitored;

[0150] In step B2, when the rate of decrease of the internal pressure of the coal mill is less than the first rate, it is determined that no leakage occurs in the coal mill;

[0151] In step B3, when the rate of decrease of the internal pressure of the coal mill is greater than the first rate, it is determined that leakage occurs in the coal mill.

[0152] In one embodiment, the method may be further implemented as follows:

[0153] In step C1, when the rate of decrease of the internal pressure of the coal mill is greater than the first rate and less than the second rate, it is determined that the coal mill has a primary leakage, and the steam flow rate is increased and the purge time is extended;

[0154] In step C2, when the rate of decrease of the internal pressure of the coal mill is greater than or equal to the second rate, the coal mill is determined to have a secondary leak, the purge is determined to have failed, the purge is immediately interrupted, the coal mill is locked, and a maintenance alarm is triggered.

[0155] In summary, this coal mill fire steam purging solution is dedicated to ensuring safe, efficient, and reliable operation of the mill, offering significant safety and economic advantages. The solution encompasses multiple measures: real-time monitoring of key parameters ensures effective inerting to prevent deflagration, dynamically adjusting purge time based on coal type; real-time verification of steam quality, intelligent calculation of minimum steam flow, and monitoring of pressure fluctuations to optimize purge effectiveness; closed-loop control processes and fault self-diagnosis enhance automation and reduce human error; improved adaptability to special operating conditions such as high-volatile coal and emergency shutdowns; and protection against wet steam effects to extend equipment life and reduce maintenance costs. Key components of the solution include real-time verification of steam quality, calculation and dynamic adjustment of minimum steam flow, real-time monitoring of oxygen concentration and pressure, dynamic adjustment of purge time, and fault self-diagnosis and closed-loop control. This comprehensive technical approach ensures the precision, automation, and safety of coal mill fire steam purging. Especially for high-risk scenarios, this approach leverages multi-parameter model collaborative optimization and real-time decision-making logic to create a technical barrier to prevent deflagration.

[0156] Figure 2 FIG. 1 is a structural diagram of a coal mill purge device according to an embodiment of the present application. Figure 2 Shown, including:

[0157] The first determining module 201 is configured to determine the type of steam used to purge the coal mill according to the coal type information of the residual coal powder in the coal mill when the coal mill meets the purge conditions;

[0158] An injection module 202 is configured to inject the corresponding type of purge steam into the coal mill;

[0159] The detection module 203 is used to detect whether the type and pressure of the injected steam are qualified;

[0160] The judgment module 204 is used to judge whether the steam flow rate meets the minimum purge steam flow rate requirement when the steam type and steam pressure are qualified;

[0161] The timing module 205 is used to time the purge time when the steam flow rate meets the minimum purge steam flow rate requirement;

[0162] The first monitoring module 206 is configured to monitor the internal pressure of the coal mill during the purging process and adjust the steam pressure according to the internal pressure of the coal mill so that the internal pressure of the coal mill increases at a specific rate;

[0163] The second monitoring module 207 is used to monitor the oxygen content inside the coal mill when the timed purge time reaches a preset time;

[0164] The second determining module 208 is configured to determine that the purging is successful when the oxygen content inside the coal mill is lower than a preset content.

[0165] In one embodiment, the detection module includes:

[0166] An acquisition submodule, used for acquiring the steam pressure and steam inlet temperature of the purge steam;

[0167] The first judgment submodule is used to judge whether the steam type is qualified according to the steam pressure and steam inlet temperature;

[0168] The second judgment submodule is used to judge whether the steam pressure is qualified according to the steam pressure threshold and the pressure fluctuation threshold.

[0169] In one embodiment, when it is determined that the type of steam used to purge the coal mill is saturated steam, the first judgment submodule is further configured to:

[0170] Look up the corresponding saturation temperature table according to the steam pressure to determine the saturation temperature range corresponding to the current steam pressure;

[0171] When the steam temperature is within the saturation temperature range or the steam temperature is higher than the maximum value of the saturation temperature range, the steam type is determined to be qualified;

[0172] When the steam temperature is lower than the minimum value of the saturation temperature range, it indicates that the steam type is unqualified.

[0173] In one embodiment, the second judgment submodule is further configured to:

[0174] When the steam pressure is greater than a preset steam pressure threshold and the pressure fluctuation is less than or equal to a preset pressure fluctuation threshold, it is determined that the steam pressure is qualified.

[0175] In one embodiment, the detection module further includes:

[0176] The determination submodule is used to determine that the purge has failed when the steam type and / or steam pressure test fails, close the steam purge valve, and prompt that the steam contains water or the pressure is unstable and requires processing.

[0177] In one embodiment, the minimum purge steam flow rate is determined as follows:

[0178] The minimum steam quantity required for the coal mill is determined according to the following formula:

[0179]

[0180] Among them, Q steam is the required fire steam mass flow rate; V is the coal mill volume; C0 is the initial oxygen concentration; C1 is the preset oxygen content of the coal mill to meet the purge requirements after the purge is completed; ρ air is the air density; η is the inerting efficiency; t is the preset time for the coal mill to complete the purge; M air is the molar mass of air; Msteam is the molar mass of steam.

[0181] In one embodiment, the apparatus further comprises:

[0182] The third determination module is used to determine that the steam flow is unqualified when the steam flow is less than the minimum purge steam flow, exit the purge process, close the steam purge valve, and prompt that the steam purge flow is insufficient and the purge fails.

[0183] In one embodiment, the apparatus further comprises:

[0184] The fourth determining module is used to determine the preset time for the coal mill to complete the purge and the preset oxygen content required for the coal mill to meet the purge requirements after the purge is completed according to the coal type information of the residual coal powder in the coal mill.

[0185] In one embodiment, the apparatus further comprises:

[0186] The third monitoring module is used to monitor the internal pressure stability of the coal mill after the purging is successful;

[0187] a fifth determining module, configured to determine that no leakage occurs in the coal mill when the rate of decrease of the internal pressure of the coal mill is less than the first rate;

[0188] The fifth determination module is further configured to determine that leakage occurs in the coal mill when the rate of decrease in the internal pressure of the coal mill is greater than the first rate.

[0189] In one embodiment, the fifth determining module is further configured to:

[0190] When the rate of decrease of the internal pressure of the coal mill is greater than the first rate and less than the second rate, it is determined that the coal mill has a primary leakage, and the steam flow rate is increased and the purge time is extended;

[0191] When the rate of decrease of the internal pressure of the coal mill is greater than or equal to the second rate, the coal mill is determined to have a secondary leak, the purge is determined to have failed, the purge is immediately interrupted, the coal mill is locked and a maintenance alarm is triggered.

[0192] Figure 3 FIG. 1 is a schematic diagram of the hardware structure of a coal mill purge system in one embodiment of the present application. Figure 3 As shown, the coal mill purge system includes:

[0193] at least one processor 320; and,

[0194] A memory 304 in communication with the at least one processor 320; wherein,

[0195] The memory 304 stores instructions executable by the at least one processor 320 for implementing the coal mill purging method as described in any of the embodiments above.

[0196] Referring to Figure 3 The coal mill purging system 300 can include one or more of the following components: a processing component 302, a memory 304, a power supply component 306, a multimedia component 308, an audio

[0197] The processing component 302 generally controls the overall operations of the coal mill purging system 300. The processing component 302 can include one or more processors 320 to execute instructions to complete all or part of the steps of the above-described methods. In addition, the processing component 302 can include one or more modules to facilitate the interaction between the processing component 302 and other components. For example, the processing component 302 can include a multimedia module to facilitate the interaction between the multimedia component 308 and the processing component 302.

[0198] The memory 304 is configured to store various types of data to support the operation of the coal mill purging system 300. Examples of these data include instructions for any application or method operating on the coal mill purging system 300, such as text, pictures, videos, etc. The memory 304 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk.

[0199] The power supply component 306 provides power to the various components of the coal mill purging system 300. The power supply component 306 can include a power management system, one or more power supplies, and other components associated with generating, managing and distributing power to the coal mill purging system 300.

[0200] The multimedia component 308 includes a screen that provides an output interface between the coal mill purge system 300 and the user. In some embodiments, the screen may include a liquid crystal display (LCD) and a touch panel (TP). If the screen includes a touch panel, the screen may be implemented as a touch screen to receive input signals from the user. The touch panel includes one or more touch sensors to sense touches, slides, and gestures on the touch panel. The touch sensor can not only sense the boundaries of the touch or slide action, but also detect the duration and pressure associated with the touch or slide operation. In some embodiments, the multimedia component 308 may also include a front camera and / or a rear camera. When the coal mill purge system 300 is in an operating mode, such as a shooting mode or a video mode, the front camera and / or the rear camera can receive external multimedia data. Each front camera and rear camera can be a fixed optical lens system or have focal length and optical zoom capabilities.

[0201] The audio component 310 is configured to output and / or input audio signals. For example, the audio component 310 includes a microphone (MIC) configured to receive external audio signals when the coal mill purge system 300 is in an operating mode, such as an alarm mode, a recording mode, a voice recognition mode, or a voice output mode. The received audio signals may be further stored in the memory 304 or transmitted via the communication component 316. In some embodiments, the audio component 310 also includes a speaker for outputting audio signals.

[0202] I / O interface 312 provides an interface between processing component 302 and peripheral interface modules, such as a keyboard, click wheel, buttons, etc. These buttons may include but are not limited to: a home button, volume buttons, a start button, and a lock button.

[0203] The sensor assembly 314 includes one or more sensors for providing various aspects of status assessment for the coal mill purge system 300. For example, the sensor assembly 314 may include a sound sensor. In addition, the sensor assembly 314 can detect the open / closed state of the coal mill purge system 300, the relative positioning of components, such as the display and keypad of the coal mill purge system 300, and the sensor assembly 314 can also detect the operating state of the coal mill purge system 300 or a component of the coal mill purge system 300. The sensor assembly 314 may include a proximity sensor configured to detect the presence of nearby objects without any physical contact. The sensor assembly 314 may also include a light sensor, such as a CMOS or CCD image sensor, for use in imaging applications. In some embodiments, the sensor assembly 314 may also include a magnetic sensor, a pressure sensor, a material pile thickness sensor, or a temperature sensor.

[0204] The communication component 316 is configured to enable the coal mill purge system 300 to provide the ability to communicate with other devices and cloud platforms in a wired or wireless manner. The coal mill purge system 300 can access a wireless network based on a communication standard, such as WiFi, 2G or 3G, or a combination thereof. In an exemplary embodiment, the communication component 316 receives a broadcast signal or broadcast-related information from an external broadcast management system via a broadcast channel. In an exemplary embodiment, the communication component 316 also includes a near field communication (NFC) module to facilitate short-range communication. For example, the NFC module can be implemented based on radio frequency identification (RFID) technology, infrared data association (IrDA) technology, ultra-wideband (UWB) technology, Bluetooth (BT) technology and other technologies.

[0205] In an exemplary embodiment, the coal mill purge system 300 can be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors or other electronic components to perform the coal mill purge method described in any of the above embodiments.

[0206] The present application also provides a computer-readable storage medium. When the instructions in the storage medium are executed by a processor corresponding to the coal mill purge system, the coal mill purge system can implement the coal mill purge method described in any of the above embodiments.

[0207] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage and optical storage, etc.) that contain computer-usable program code.

[0208] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0209] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0210] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0211] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A coal mill purging method, characterized in that: include: When the coal mill meets the purging conditions, determining the type of steam used to purge the coal mill according to the coal type information of the residual coal powder in the coal mill; injecting the corresponding type of purge steam into the coal mill; Check whether the type and pressure of injected steam are qualified; When the steam type and steam pressure are qualified, determine whether the steam flow meets the minimum purge steam flow requirement; When the steam flow rate meets the minimum purge steam flow rate requirement, the purge time is counted; During the purging process, the internal pressure of the coal mill is monitored, and the steam pressure is adjusted according to the internal pressure of the coal mill so that the internal pressure of the coal mill increases at a specific rate; When the timed purge time reaches the preset time, the oxygen content inside the coal mill is monitored; When the oxygen content inside the coal mill is lower than the preset content, it is determined that the purging is successful.

2. The method according to claim 1, wherein The detection of whether the type and pressure of the injected steam are qualified includes: Obtain the steam pressure and steam inlet temperature of the purge steam; Determine whether the steam type is qualified based on the steam pressure and steam inlet temperature; Whether the steam pressure is qualified is determined based on the steam pressure threshold and the pressure fluctuation threshold.

3. The method according to claim 2, wherein When it is determined that the type of steam used for purging the coal mill is saturated steam, judging whether the type of steam is qualified based on the steam pressure and the steam inlet temperature includes: Look up the corresponding saturation temperature table according to the steam pressure to determine the saturation temperature range corresponding to the current steam pressure; When the steam temperature is within the saturation temperature range or the steam temperature is higher than the maximum value of the saturation temperature range, the steam type is determined to be qualified; When the steam temperature is lower than the minimum value of the saturation temperature range, it indicates that the steam type is unqualified.

4. The method according to claim 2, wherein The method further comprises: When the steam type and / or steam pressure test fails, it is determined that the purge has failed.

5. The method according to claim 1, wherein The minimum purge steam flow rate is determined as follows: The minimum steam quantity required for the coal mill is determined according to the following formula: Among them, Q steam is the required fire steam mass flow rate; V is the coal mill volume; C0 is the initial oxygen concentration; C1 is the preset oxygen content of the coal mill to meet the purge requirements after the purge is completed; ρ air is the air density; η is the inerting efficiency; t is the preset time for the coal mill to complete the purge; M air is the molar mass of air; M steam is the molar mass of steam.

6. The method according to claim 1 or 5, wherein: The method further comprises: The preset time for the coal mill to complete the purging and the preset oxygen content required for the coal mill to meet the purging requirements after the purging is completed are determined according to the coal type information of the residual coal powder in the coal mill.

7. The method according to claim 1, wherein The method further comprises: After successful purging, monitor the internal pressure stability of the coal mill; When the rate of decrease of the internal pressure of the coal mill is less than the first rate, it is determined that the coal mill has no leakage; When the rate of decrease of the internal pressure of the coal mill is greater than the first rate, it is determined that leakage occurs in the coal mill.

8. A coal mill purge device, characterized in that: include: A first determining module is configured to determine the type of steam used to purge the coal mill according to the coal type information of the residual coal powder in the coal mill when the coal mill meets the purge conditions; an injection module for injecting the corresponding type of purge steam into the coal mill; Detection module, used to detect whether the type and pressure of injected steam are qualified; A judgment module is used to judge whether the steam flow meets the minimum purge steam flow requirement when the steam type and steam pressure are qualified; A timing module is used to time the purge time when the steam flow rate meets the minimum purge steam flow rate requirement; a first monitoring module, configured to monitor the internal pressure of the coal mill during the purging process and adjust the steam pressure according to the internal pressure of the coal mill so that the internal pressure of the coal mill increases at a specific rate; The second monitoring module is used to monitor the oxygen content inside the coal mill when the timed purge time reaches a preset time; The second determination module is used to determine that the purging is successful when the oxygen content inside the coal mill is lower than a preset content.

9. A coal mill purge system, characterized in that: include: at least one processor; as well as, a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to implement the coal mill purging method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that When the instructions in the storage medium are executed by a processor corresponding to the coal mill purge system, the coal mill purge system can implement the coal mill purge method according to any one of claims 1 to 7.

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