Method and device for controlling the output of a coal mill

Abstract

A coal mill output control method and device, the method comprises the following steps: determining the starting mode of the coal mill according to the boiler state parameters; performing valve action test on all outlet pneumatic doors; performing pilot ignition on the burner by the oil ignition device to determine the number of burners successfully ignited; selecting the outlet pneumatic door to be opened among the outlet pneumatic doors corresponding to the successfully ignited burners; performing powder pipe wind speed control and initial coal quantity control according to the preset primary air volume and the wind powder concentration to determine the fuel quantity of a single burner nozzle and the total fuel quantity; gradually opening the outlet pneumatic doors that are not opened when the total fuel quantity reaches the preset fuel quantity threshold; when all the outlet pneumatic doors are opened and the opening delay reaches the preset time threshold or the coal quantity of the coal mill reaches the preset coal quantity threshold, the oil ignition starting mode is removed. The present application reduces the initial coal quantity of the oil ignition on the basis of ensuring stable combustion, reduces the thermal shock and temperature sudden change of the heating surface during the cold state starting, and ensures the safety of the equipment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coal mill control, in particular to a coal mill output control method and device. BACKGROUND

[0002] In order to save start-up costs, new power plants generally use plasma or micro-oil ignition and other low-oil ignition technologies according to the coal quality, and existing units are also transformed accordingly. Low-oil ignition technology generally does not design a large oil gun to achieve direct ignition of a cold furnace; however, due to the problem of too small output of a medium-speed coal mill causing vibration, the minimum output of the coal mill is 25% of the maximum guaranteed output, so that after the coal mill is started and powder is thrown into the furnace during the cold-state start-up of the boiler, a large amount of fuel is suddenly thrown into the furnace for combustion, the heat and radiation heat exchange of the generated flue gas cause the wall temperature change rate of the high-temperature zone at the outlet of the furnace to be as high as 5-10 ℃ / min, and the sudden change in temperature is extremely easy to cause the peeling of the internal oxide skin of the tube wall of the heating surface, causing the risk of boiler tube explosion and unit shutdown. The existing output control technology of the coal mill has problems such as being unable to guarantee stable ignition. SUMMARY

[0003] In view of the problems in the prior art, the main purpose of the embodiments of the present application is to provide a coal mill output control method and device, which reduces the initial coal quantity of low-oil ignition on the basis of guaranteeing stable combustion.

[0004] In order to achieve the above-mentioned purpose, the embodiments of the present application provide a coal mill output control method, which comprises the following steps:

[0005] According to the obtained boiler state parameters, the starting mode of the coal mill is determined, if the starting mode of the coal mill is a low-oil ignition starting mode, valve action tests are performed on all outlet pneumatic doors of the coal mill to obtain test results;

[0006] If the test results are normal valve actions, low-oil ignition equipment pilot ignition is performed on the burners corresponding to all outlet pneumatic doors of the coal mill to determine the number of burners that successfully ignite;

[0007] If the number of successfully ignited burners is not less than a preset opening number, adjacent outlet pneumatic doors of the opening number are selected and opened from the outlet pneumatic doors corresponding to the successfully ignited burners;

[0008] According to a preset primary air quantity and a preset wind-powder concentration, the powder pipe air speed of the coal mill is controlled and the initial coal quantity is controlled, and the fuel quantity of a single burner nozzle and the total fuel quantity are determined;

[0009] When the total fuel quantity reaches a preset fuel quantity threshold, the outlet pneumatic doors that are not opened are gradually opened according to the fuel quantity of the single burner nozzle;

[0010] When all the outlet pneumatic doors of the coal mill are opened, and the opening time delay reaches a preset time threshold or the coal quantity of the coal mill reaches a preset coal quantity threshold, the low-oil ignition start mode of the coal mill is cut off.

[0011] Optionally, in an embodiment of the present application, the boiler state parameters include a boiler downtime, a main steam pressure and a temperature parameter.

[0012] Optionally, in an embodiment of the present application, the method further comprises:

[0013] comparing the boiler downtime in the boiler state parameters with a preset downtime to determine the start mode of the coal mill; wherein the start mode of the coal mill includes a low-oil ignition start mode, a low-oil ignition mode and a normal mode.

[0014] Optionally, in an embodiment of the present application, after the powder pipe air speed control and the initial coal quantity control of the coal mill are performed, and the fuel quantity of a single burner nozzle and the total fuel quantity are determined, the method further comprises:

[0015] increasing the powder quantity of the coal mill by using a preset dynamic separator frequency, and controlling the loading force of the coal mill by using the opening of the overflow valve, so that the coal quantity in the coal mill is kept within a preset range;

[0016] increasing the fuel quantity of the coal mill according to the temperature and pressure rising rate of the coal mill.

[0017] The embodiment of the present application further provides a coal mill output control device, which comprises:

[0018] a start mode module, configured to determine the start mode of the coal mill according to the obtained boiler state parameters, and perform valve action test on all the outlet pneumatic doors of the coal mill to obtain a test result if the start mode of the coal mill is a low-oil ignition start mode;

[0019] a test ignition module, configured to perform low-oil ignition equipment test ignition on the burners corresponding to all the outlet pneumatic doors of the coal mill if the test result is that the valve action is normal, and determine the number of burners that ignite successfully;

[0020] a pneumatic door selection module, configured to select the adjacent outlet pneumatic doors of the number of open burners to open if the number of burners that ignite successfully is not less than a preset number of open burners;

[0021] a fuel quantity module, configured to perform powder pipe air speed control and initial coal quantity control of the coal mill according to a preset primary air quantity and a preset air-powder concentration, and determine the fuel quantity of a single burner nozzle and the total fuel quantity;

[0022] A pneumatic door opening module is configured to open the unopened outlet pneumatic door gradually according to the fuel amount of the single burner nozzle when the total fuel amount reaches the preset fuel amount threshold.

[0023] A mode cutting module is configured to cut the low-oil ignition start mode of the coal mill when all the outlet pneumatic doors of the coal mill are opened and the opening delay reaches the preset time threshold or the coal amount of the coal mill reaches the preset coal amount threshold.

[0024] Optionally, in an embodiment of the present application, the boiler state parameters include the boiler downtime, the main steam pressure and temperature parameters.

[0025] Optionally, in an embodiment of the present application, the start mode module is further configured to compare the boiler downtime in the boiler state parameters with a preset downtime to determine the start mode of the coal mill; wherein the start mode of the coal mill includes the low-oil ignition start mode, the low-oil ignition mode and the normal mode.

[0026] Optionally, in an embodiment of the present application, the device further includes:

[0027] A loading force module is configured to increase the pulverized coal amount of the coal mill by using the preset dynamic separator frequency, and control the loading force of the coal mill by using the opening degree of the overflow valve, so that the internal coal amount of the coal mill is kept within a preset range.

[0028] A fuel increasing module is configured to increase the fuel amount of the coal mill according to the temperature and pressure rising rate of the coal mill.

[0029] The present application further provides an electronic device, including a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the above method when executing the program.

[0030] The present application further provides a computer readable storage medium, which stores a computer program for executing the above method.

[0031] The present application further provides a computer program product, including computer programs / instructions, which implement the steps of the above method when executed by a processor.

[0032] The present application controls the opening of the outlet pneumatic door to protect the coal mill, optimizes the start control of the air door fire detection, reduces the initial coal amount of the low-oil ignition on the basis of ensuring stable combustion, reduces the thermal shock and temperature change of the heated surface during cold start, reduces the risk of boiler oxide peeling and pipe explosion, and ensures the safety of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments description will be briefly introduced. Obviously, the accompanying drawings in the following description only represent some embodiments of the present application, and for those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0034] Figure 1 A flow chart of a coal mill output control method according to an embodiment of the present application;

[0035] Figure 2 A load force control flow chart according to an embodiment of the present application;

[0036] Figure 3 A flow chart of determining a starting mode according to a boiler state parameter according to an embodiment of the present application;

[0037] Figure 4 A flow chart of a low-oil ignition starting mode according to an embodiment of the present application;

[0038] Figure 5 A structure schematic diagram of a coal mill output control device according to an embodiment of the present application;

[0039] Figure 6 A structure schematic diagram of a coal mill output control device according to another embodiment of the present application;

[0040] Figure 7 A structure schematic diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0041] The present application provides a coal mill output control method and device.

[0042] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments only represent some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without any creative effort belong to the scope of protection of the present application.

[0043] The prior art discloses a method for controlling the output of a coal mill during boiler ignition, according to the positive correlation between the rotational speed of the coal mill and the output, the rotational speed of the coal mill can be adjusted to adjust the output of the coal mill; the rotational speed of the coal mill is controlled by using a high-voltage frequency conversion speed regulating device, so that the rotational speed can be continuously increased and decreased during the first ignition process, and the rotational speed of the coal mill is changed according to different stages of ignition. The method uses a high-voltage frequency conversion speed regulating device to control the rotational speed of the coal mill, without the need to modify the inside of the coal mill, so that the continuous change of the rotational speed of the coal mill can be controlled, and the reduction capacity and adjustment capacity are achieved.

[0044] However, the technical scheme needs to add a set of high-voltage frequency conversion device to control the rotational speed of the coal mill, and is aimed at the four-corner tangential combustion, and cannot guarantee stable ignition; and the conventional pulverizing system requires that fire detection 4 takes 2 no-fire to jump the mill, and the present application does not involve it, thereby improving the control efficiency.

[0045] The prior art also discloses a method for reducing the minimum output of a medium-speed coal mill based on a rare earth motor frequency conversion adjustment, the method performs minimum output test and coal powder fineness test of the coal mill under different rotational speeds on the pulverizing system, and then reduces the rotational speed of the coal mill and the minimum output of the medium-speed coal mill through a frequency conversion control unit according to the test results; not only can the problem of difficult control of the temperature and pressure rise rate during the initial start of the boiler be effectively solved, but also the rare earth motor frequency conversion adjustment can reduce the power consumption of the coal mill and play a role in energy saving and emission reduction.

[0046] However, the technical scheme reduces the minimum coal quantity by controlling the rotational speed of the coal mill through a rare earth motor frequency conversion, but the primary air quantity control is not mentioned, and too low coal powder concentration cannot guarantee stable ignition; and the conventional pulverizing system requires that fire detection 4 takes 2 no-fire to jump the mill, and the present application does not involve it, thereby improving the control efficiency.

[0047] As Figure 1 The flow chart of the coal mill output control method is shown in the figure, and the execution subject of the coal mill output control method provided by the present application includes but is not limited to a computer. The present application reduces the initial coal quantity of the less-oil ignition on the basis of guaranteeing stable combustion by controlling the opening of the outlet pneumatic door to interlock the protection of the coal mill, and optimizing the start control of the air door fire detection, reduces the thermal shock and temperature sudden change of the heating surface during the cold start, reduces the risk of boiler oxide peeling and pipe explosion, and guarantees the safety of the equipment. The method shown in the figure includes:

[0048] Step S1, according to the acquired boiler state parameters, the starting mode of the coal mill is determined, if the starting mode of the coal mill is the less-oil ignition starting mode, the valve action test of all outlet pneumatic doors of the coal mill is performed, and the test result is obtained;

[0049] Step S2, if the test result is that the valve action is normal, then the few-oil ignition equipment of the burner corresponding to all the outlet pneumatic doors of the coal mill is test-fired to determine the number of the burners that are successfully ignited;

[0050] Step S3, if the number of the burners that are successfully ignited is not less than the preset opening number, then the adjacent outlet pneumatic doors of the opening number are opened in the outlet pneumatic doors corresponding to the burners that are successfully ignited;

[0051] Step S4, according to the preset primary air volume and the preset air-powder concentration, the powder pipe air speed control and the initial coal amount control are performed on the coal mill, and the fuel amount of a single burner nozzle and the total fuel amount are determined;

[0052] Step S5, when the total fuel amount reaches the preset fuel amount threshold, the outlet pneumatic doors that are not opened are gradually opened according to the fuel amount of a single burner nozzle;

[0053] Step S6, when all the outlet pneumatic doors of the coal mill are opened, and the opening delay reaches the preset time threshold or the coal amount of the coal mill reaches the preset coal amount threshold, the few-oil ignition start mode of the coal mill is cut off.

[0054] As an embodiment of the present application, the boiler state parameters include the boiler shutdown time, the main steam pressure and temperature parameters.

[0055] In the embodiment, according to the obtained boiler state parameters, the determination of the coal mill start mode includes: comparing the boiler shutdown time in the boiler state parameters with the preset shutdown time to determine the coal mill start mode; wherein the coal mill start mode includes the few-oil ignition start mode, the few-oil ignition mode and the normal mode.

[0056] The boiler state parameters refer to the boiler shutdown time, the main steam pressure and temperature parameters, and the parameter acquisition mode can adopt the existing mode, which is not described herein. The coal mill start mode is selected according to the boiler state. Specifically, the coal mill start mode includes the few-oil ignition start mode, the few-oil ignition mode and the normal mode.

[0057] Further, the cold start (the shutdown time is greater than 72 hours) and the warm start (the shutdown time is greater than 10 hours and less than 72 hours) automatically select the few-oil ignition start mode; the hot start (the shutdown time is greater than 1 hour and less than 10 hours) or the extremely hot start (the shutdown time is less than 1 hour) automatically selects the few-oil ignition mode; and when the unit load is greater than the minimum stable combustion load, the normal mode is selected by default.

[0058] Further, if the start mode of the coal mill is the low-oil ignition start mode, according to the preset coal mill fire detection protection logic, the number N of the planned opened coal mill outlet pneumatic doors is selected, that is, the preset opening number. N is at least one more than the number required by the fire detection, and for a specific coal mill and burner, the number of N is fixed.

[0059] Further, the control switch opens all the outlet pneumatic doors M of the coal mill, confirms and records whether the valve action is normal, and thus obtains the test result; in order to avoid powder accumulation in the closed powder pipe, it is required that the outlet pneumatic door M must be arranged on the vertical pipe, and there should be no horizontal pipe between the outlet pneumatic door and the top outlet of the coal mill.

[0060] Further, if the test result is that the valve action is normal, the low-oil ignition device / equipment of the burner B corresponding to the outlet pneumatic door M is tested for ignition or arc drawing, the burner nozzle of which is confirmed and recorded to be successfully ignited, and it is required that the number of the successfully ignited burners is greater than or equal to N.

[0061] Further, in the outlet pneumatic door corresponding to the successfully ignited burner, N pneumatic doors of the adjacent burners are selected to be opened, if multiple combinations are met, the priority is selected in turn, and the corresponding low-oil ignition device is ignited (arc drawing); for example, M2-M4→M3-M5→M1-M3→M4-M6.

[0062] Specifically, the priority is the opening sequence of the N pneumatic doors in turn, and the priority can be determined in advance according to the arrangement position of the burner.

[0063] Among them, the start permission condition of the coal mill is that in the low-oil ignition start mode, the outlet pneumatic door of the coal mill is fully opened and in place, and the number of the corresponding burners successfully ignited by the low-oil ignition is greater than or equal to N. In the low-oil ignition start mode, the burner fire detection disappears (the falling edge pulse is taken) to associate the corresponding outlet pneumatic door. The protection trip logic of the coal mill fire detection without fire is that the coal feeder runs for 180S, and the fire detection of the coal burner (B-N+1) is without fire.

[0064] Further, the control mode of the coal supply and the air volume controls the primary air volume according to the requirement that the powder pipe air speed is not less than 16m / s, and controls the initial coal quantity according to the requirement of the minimum wind-powder concentration (generally 0.2kg / kg) of the low-oil ignition, so that the fuel quantity put into the furnace in the low-oil ignition start mode is reduced by 50-60% compared with the normal mode, which greatly reduces the rate of temperature sudden change. In the case of stable ignition, the fuel quantity q of a single burner nozzle and the total fuel quantity Q=Nq are recorded.

[0065] Specifically, the primary air volume of the coal mill = air speed * powder pipe area * density, and the initial coal quantity = minimum wind-powder concentration * air volume.

[0066] As an embodiment of the present application, as shown in Figure 2As shown, after the pulverizer is controlled by the pulverizing pipe wind speed and the initial coal amount, and the fuel amount of the single burner nozzle and the total fuel amount are determined, the method further comprises:

[0067] In step S21, the preset dynamic separator frequency is used to increase the pulverizer return amount, and the opening of the overflow valve is used to control the loading force of the pulverizer, so that the internal coal amount of the pulverizer is kept in the preset range.

[0068] In step S22, the fuel amount of the pulverizer is increased according to the temperature and pressure increasing rate of the pulverizer.

[0069] The pulverizer loading force control mode is used to reduce the vibration of the pulverizer caused by the small coal amount in the start-up mode. The dynamic separator frequency is controlled at 40 Hz to increase the return amount. The fixed and variable loading control is used in the middle position. The normal force and the counterforce pressure set value are consistent, that is, the self-weight of the grinding roller is used to grind the raw coal, and the coal amount in the pulverizer is controlled in a reasonable range through multiple cycles of separation of the dynamic separator.

[0070] Further, according to the change of the temperature and pressure increasing rate, the fuel amount is increased in time. When the total fuel amount Q increases to (N+1)q, the oil light ignition device of the next adjacent burner nozzle is automatically put into operation. After confirming the successful ignition, the corresponding outlet pneumatic door is opened. At this time, the fuel amount of the single burner nozzle is reduced to q again. With the increase of the total fuel amount, all outlet pneumatic doors are gradually opened.

[0071] Further, with the increase of the total fuel amount, all outlet pneumatic doors are gradually opened. When the outlet pneumatic door of the pulverizer is fully opened and delayed for 30 seconds or the coal amount of the pulverizer is greater than 50% of the maximum guaranteed output, the minimum start-up mode is automatically removed and converted to the oil light ignition mode. When the unit load is greater than the minimum stable combustion load, the oil light ignition mode is automatically removed and converted to the normal mode, so as to avoid the shutdown of the oil light ignition device caused by forgetting to switch the mode and causing the pulverizer to trip.

[0072] Further, according to the change of the temperature and pressure increasing rate, the fuel amount is increased in time. When the total fuel amount Q increases to (N+1)q, the oil light ignition device of the next adjacent burner nozzle is automatically put into operation. After confirming the successful ignition, the corresponding outlet pneumatic door is opened. At this time, the fuel amount of the single burner nozzle is reduced to q again. With the increase of the total fuel amount, all outlet pneumatic doors are gradually opened.

[0073] Specifically, the dynamic separator is arranged in the coal mill and is controlled by frequency conversion. The centrifugal force can be increased and the powder return amount can be increased by controlling the frequency to be 40 Hz. In addition, the constant and variable loading is one of the control modes of the hydraulic loading force of the coal mill, and the electromagnetic valve can be controlled to be in the middle position. The positive and negative action force control is one of the control modes of the hydraulic loading force of the coal mill, and the positive and negative action forces are respectively applied to the mill roller to exert downward and upward forces. The values of the positive and negative action forces can be controlled by changing the opening degree of the overflow valve.

[0074] In addition, when the main steam temperature change rate is less than 2 ℃ / min and the pressure change rate is less than 0.15 MPa / min, the fuel amount is increased by 2 t / h each time, and the interval is 30 S.

[0075] Further, when the coal mill outlet pneumatic door is fully opened for 30 S or the coal mill coal amount is greater than 50% of the maximum guaranteed output, the minimum starting mode is automatically removed, and the oil point ignition mode is converted; when the unit load is greater than the minimum stable combustion load, the oil point ignition mode is automatically removed, and the normal mode is converted, so that the mill is tripped due to forgetting to switch the mode and stopping the oil point ignition device.

[0076] The present application controls the opening of the outlet pneumatic door to interlock the protection of the coal mill, optimizes the starting control of the air door fire detection, reduces the initial coal amount of the oil point ignition on the basis of ensuring stable combustion, reduces the thermal shock and temperature change of the heating surface during the cold state starting period, reduces the risk of boiler oxide peeling and pipe explosion, and ensures the safety of the equipment.

[0077] The cyclone burner relies on the high-temperature flue gas to heat the pulverized coal, and the oil point ignition ignites the pulverized coal by the high-temperature heat generated by micro-oil or plasma, so that the cyclone burner equipped with the oil point ignition can realize stable combustion by relying on its good air power field.

[0078] In a specific embodiment of the present application, the present application is directed to a combustion system configured with an oil point ignition cyclone burner, and the starting mode thereof is divided into an oil point ignition starting mode, an oil point ignition mode and a normal mode. The oil point ignition mode and the normal mode are existing modes, and the oil point ignition starting mode is a minimum output control method newly proposed by the present application.

[0079] For a large-scale cyclone burner boiler, four powder pipes corresponding to four burners are arranged at the outlet of each coal mill of a conventional 300 MW capacity level boiler, six powder pipes corresponding to six burners are arranged at the outlet of each coal mill of a 600 MW unit, and four powder pipes corresponding to eight burners are arranged at the outlet of each coal mill of a 1000 MW unit through a coal powder distributor, and each burner is independently configured with a fire detection probe capable of monitoring the ignition condition of the coal powder.

[0080] As shown in Figure 4 The oil point ignition starting mode starting program specifically includes the following processes:

[0081] 1. For example Figure 3 As shown, to control the initial fuel input (heat load) of the boiler and match the furnace and heating surface temperatures, the coal mill start-up mode is selected based on the boiler status parameters. For cold starts (shutdown time greater than 72 hours) and warm starts (shutdown time greater than 10 hours and less than 72 hours), the low-oil ignition start-up mode is automatically selected; for hot starts (shutdown time greater than 1 hour and less than 10 hours) or extremely hot starts (shutdown time less than 1 hour), the low-oil ignition mode is automatically selected; when the unit load is greater than the minimum stable combustion load, the normal mode is selected by default.

[0082] 2. Based on the coal mill flame detection protection logic, select the planned number N of pneumatic valves to be opened at the coal mill outlet. N must be at least one more than the number required for flame detection to show a flame. For boilers with swirl burners, a typical 300MW pulverizing system has 4 burners, and the coal mill trip protection is "3 out of 4 burners with no flame detection" (equivalent to or 1 out of 4 having a flame); a 600MW unit has 6 burners, and the coal mill trip protection is "4 out of 6 burners with no flame detection" (equivalent to or 2 out of 6 having a flame); a 1000MW unit has 8 burners, and the coal mill trip protection is "5 out of 8 burners with no flame detection" (equivalent to or 3 out of 8 having a flame). Therefore, N should be 2, 3, or 4 respectively. For a specific coal mill and burner, the value of N is fixed. The following example uses a 600MW unit with 6 burners.

[0083] 3. Open and close all outlet pneumatic valves M of the coal mill once to confirm and record whether the valves operate normally; in order to avoid powder accumulation in the closed powder pipes, the outlet pneumatic valves M must be arranged on vertical pipes, and there must be no horizontal pipes between the outlet pneumatic valves and the top outlet of the coal mill.

[0084] 4. Test ignition or arc test of the low-oil ignition device of burner B corresponding to the outlet pneumatic valve M, confirm and record the burner nozzles that successfully ignite, and require that the number of B successfully ignited be greater than or equal to N.

[0085] 5. Select N pneumatic doors of adjacent burners to open. If multiple combinations are satisfied, select them in order of priority and ignite (arc-start) the corresponding low-oil ignition device; for example, M2-M4→M3-M5→M1-M3→M4-M6.

[0086] 6. The start-up conditions for the coal mill are as follows: In the low-oil ignition start-up mode, the coal mill outlet pneumatic valve is fully open and the number of corresponding burners that have successfully ignited with low oil is greater than or equal to N. In the low-oil ignition start-up mode, the corresponding outlet pneumatic valve closes when the burner flame detector disappears (taking the falling edge pulse). The protection trip logic for the coal mill flame detector failure is as follows: After the coal feeder has run for 180 seconds, there is no flame in the (B-N+1) flame detectors of the pulverized coal burners.

[0087] 7. The control method for coal feed rate and air volume: The primary air volume is controlled according to the requirement that the pulverized coal pipe velocity be no less than 16 m / s, and the initial coal quantity is controlled according to the requirement of minimum air-coal concentration for low-oil ignition (generally 0.2 kg / kg). Therefore, the amount of fuel input into the furnace under low-oil ignition start-up mode is reduced by 50-60% compared to normal mode, significantly reducing the rate of temperature change. Under stable ignition conditions, record the fuel quantity q at a single burner nozzle and the total fuel quantity Q = Nq.

[0088] 8. Coal mill loading force control method: In order to reduce the vibration of the coal mill caused by the small amount of coal in the start-up mode, the frequency of the dynamic separator is controlled at 40 Hz to increase the amount of coal returned. The constant and variable loading control is set in the middle position. The positive and negative force control is used to make the positive force and negative force pressure set values ​​consistent. That is, the raw coal is ground by the weight of the grinding rollers and separated by multiple cycles of the dynamic separator to control the amount of coal stored in the coal mill within a reasonable range.

[0089] 9. According to the change in the rate of temperature and pressure increase, the fuel quantity is increased in time. When the total fuel quantity Q increases to (N+1)q, the low-oil ignition device of the next burner nozzle is automatically activated. After confirming successful ignition, the corresponding outlet pneumatic valve is opened. At this time, the fuel quantity of a single burner nozzle is reduced back to q. As the total fuel quantity increases, all outlet pneumatic valves are gradually opened.

[0090] 10. When the pneumatic valve at the coal mill outlet is fully open and there is a 30-second delay, or when the coal quantity in the coal mill is greater than 50% of the maximum guaranteed output, the minimum start mode will be automatically cut off and the low-oil ignition mode will be switched to. When the unit load is greater than the minimum stable combustion load, the low-oil ignition mode will be automatically cut off and the normal mode will be switched to, thereby avoiding the coal mill tripping caused by forgetting to switch modes and shutting down the low-oil ignition device.

[0091] The method of this invention can reduce the initial fuel input to the furnace during cold starts by 50-60%, reduce the hot flushing of the boiler and heating surfaces, and avoid the risk of boiler tube rupture caused by scale shedding. This invention can automatically select the start-up state according to boiler parameters, increase coal input and activate multiple burners as the load program increases, and automatically switch between different modes. It provides a safe and stable ignition control method for low-coal-load cold starts and reduces mill vibration, ensuring equipment safety.

[0092] like Figure 5 The figure shows a schematic diagram of a coal mill output control device according to an embodiment of the present invention. The device shown in the figure includes:

[0093] The start-up mode module 10 is used to determine the start-up mode of the coal mill based on the obtained boiler status parameters. If the start-up mode of the coal mill is the low-oil ignition start-up mode, the valve action test is performed on all the outlet pneumatic valves of the coal mill to obtain the test results.

[0094] The pilot fire module 20 is used for pilot firing of the oil pilot firing equipment of the burners corresponding to all the outlet pneumatic doors of the coal mill if the test result is that the valve action is normal, to determine the number of burners that are successfully ignited;

[0095] The pneumatic door selection module 30 is used for selecting the opening of the adjacent outlet pneumatic doors of the number of burners that are successfully ignited if the number of burners that are successfully ignited is not less than a preset opening number.

[0096] The fuel amount module 40 is used for controlling the powder pipe air speed and the initial coal amount of the coal mill according to a preset primary air amount and a preset air-powder concentration, and determining the fuel amount of a single burner nozzle and the total fuel amount.

[0097] The pneumatic door opening module 50 is used for gradually opening the outlet pneumatic doors that are not opened according to the fuel amount of a single burner nozzle when the total fuel amount reaches a preset fuel amount threshold.

[0098] The mode cutting module 60 is used for cutting the oil pilot firing start mode of the coal mill when all the outlet pneumatic doors of the coal mill are opened and the opening delay reaches a preset time threshold or the coal amount of the coal mill reaches a preset coal amount threshold.

[0099] As an embodiment of the present application, the boiler state parameters include the boiler downtime, the main steam pressure and temperature parameters.

[0100] In the embodiment, the start mode module is further used for comparing the boiler downtime in the boiler state parameters with a preset downtime to determine the start mode of the coal mill; wherein the start mode of the coal mill includes the oil pilot firing start mode, the oil pilot firing mode and the normal mode.

[0101] As an embodiment of the present application, as shown in Figure 6 The device further includes:

[0102] The loading force module 70 is used for increasing the powder amount of the coal mill by using a preset dynamic separator frequency, and controlling the loading force of the coal mill by using the opening of the overflow valve, so as to keep the coal amount in the coal mill within a preset range.

[0103] The fuel increasing module 80 is used for increasing the fuel amount of the coal mill according to the temperature and pressure increasing rate of the coal mill.

[0104] Based on the same application concept as the above-mentioned coal mill output control method, the present application further provides the above-mentioned coal mill output control device. Since the principle of solving problems of the coal mill output control device is similar to that of the coal mill output control method, the implementation of the coal mill output control device can be referred to the implementation of the coal mill output control method, and the repeated parts will not be described herein.

[0105] The application protects the coal mill by controlling the opening of the outlet pneumatic door, and reduces the initial coal quantity of the oil ignition on the basis of ensuring stable combustion, reduces the thermal shock and temperature change of the heating surface during the cold start, reduces the risk of boiler oxide peeling and pipe explosion, and ensures the safety of the equipment.

[0106] The application further provides an electronic device, including a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the above method when executing the program.

[0107] The application further provides a computer program product, including computer programs / instructions, and the computer programs / instructions implement the steps of the above method when executed by the processor.

[0108] The application further provides a computer readable storage medium, which stores a computer program for executing the above method by a computer.

[0109] As shown in Figure 7 , the electronic device 600 can further include a communication module 110, an input unit 120, an audio processor 130, a display 160, and a power supply 170. It should be noted that the electronic device 600 does not necessarily include all the components shown in Figure 7 ; in addition, the electronic device 600 can further include components not shown in Figure 7 , which can refer to prior art.

[0110] As shown in Figure 7 , the central processor 100, also known as a controller or operation control, can include a microprocessor or other processor device and / or logic device, which receives input and controls the operation of various components of the electronic device 600.

[0111] The memory 140, for example, can be one or more of a cache, a flash memory, a hard drive, a removable media, a volatile memory, a non-volatile memory, or other suitable device. The above information related to failure can be stored, and programs for executing the information can also be stored. The central processor 100 can execute the programs stored in the memory 140 to achieve information storage or processing, etc.

[0112] The input unit 120 provides input to the central processor 100. The input unit 120 is, for example, a key or touch input device. The power supply 170 is used to provide power to the electronic device 600. The display 160 is used to display display objects such as images and text. The display can be, for example, an LCD display, but is not limited thereto.

[0113] The memory 140 can be a solid state memory such as a read only memory (ROM), a random access memory (RAM), a SIM card, etc. It can also be a memory that retains information even when power is turned off, can be selectively erased, and is provided with more data, an example of which is sometimes referred to as an EPROM, etc. The memory 140 can also be some other type of device. The memory 140 includes a buffer memory 141 (sometimes referred to as a buffer). The memory 140 can include an application / function storage 142 for storing application programs and function programs or a flow for executing the operation of the electronic device 600 by the central processing unit 100.

[0114] The memory 140 can also include a data storage 143 for storing data such as contacts, digital data, pictures, sounds, and / or any other data used by the electronic device. A driver storage 144 of the memory 140 can include various drivers of the electronic device for a communication function and / or for performing other functions of the electronic device such as a messaging application, an address book application, etc.

[0115] The communication module 110 is a transmitter / receiver 110 that transmits and receives signals via an antenna 111. The communication module (transmitter / receiver) 110 is coupled to the central processing unit 100 to provide input signals and receive output signals, which can be the same as in the case of a conventional mobile communication terminal.

[0116] Based on different communication technologies, a plurality of communication modules 110 such as a cellular network module, a Bluetooth module, and / or a wireless local area network module, etc. can be provided in the same electronic device. The communication module (transmitter / receiver) 110 is also coupled to a speaker 131 and a microphone 132 via an audio processor 130 to provide audio output via the speaker 131 and receive audio input from the microphone 132, thereby implementing a general telecommunication function. The audio processor 130 can include any suitable buffer, decoder, amplifier, etc. In addition, the audio processor 130 is also coupled to the central processing unit 100, thereby enabling recording on a local machine through the microphone 132 and enabling playing of a sound stored on the local machine through the speaker 131.

[0117] Those skilled in the art will appreciate that embodiments of the present application can be readily used as a method, a system or a computer program product. Accordingly, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) embodying computer readable program code thereon.

[0118] The present application is described in reference to the flowchart and / or block diagram of the method, apparatus (system) and computer program product according to an embodiment of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, and a combination of flows and / or blocks 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 apparatus to produce a machine, so that the instructions, which are executed via the processor of the computer or other programmable data processing apparatus, generate a means for implementing the functions specified in the flowchart and / or block diagram block or blocks. Figure 1 one or more flows and / or blocks Figure 1 an apparatus for implementing functions specified in the flowchart and / or block diagram block or blocks.

[0119] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including instruction apparatus, which implements the functions specified in the flowchart and / or block diagram block or blocks. Figure 1 one or more flows and / or blocks Figure 1 an apparatus for implementing functions specified in the flowchart and / or block diagram block or blocks.

[0120] These computer program instructions can also be loaded into a computer or other programmable data processing apparatus, so that a series of operation steps are performed on the computer or other programmable data processing apparatus to produce a computer-implemented process, so that the instructions executed on the computer or other programmable data processing apparatus provide a means for implementing the functions specified in the flowchart and / or block diagram block or blocks. Figure 1 one or more flows and / or blocks Figure 1 an apparatus for implementing functions specified in the flowchart and / or block diagram block or blocks.

[0121] The principles and implementation methods of the present application are described in the specific embodiments, and the above embodiment descriptions are only used to help understand the method of the present application and its core idea; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation methods and application scope will be changed, and the above description should not be understood as a limitation of the present application.

Claims

1. A method for controlling the output of a coal mill, characterized in that, The method includes: Based on the obtained boiler status parameters, the start-up mode of the coal mill is determined. If the start-up mode of the coal mill is a low-oil ignition start-up mode, the valve action test is performed on all the outlet pneumatic valves of the coal mill to obtain the test results. If the test result indicates that the valve operates normally, then a low-oil ignition test ignition is performed on all the burners corresponding to the outlet pneumatic valves of the coal mill to determine the number of burners that successfully ignited. If the number of burners that have successfully ignited is not less than the preset number of openable burners, then among the outlet pneumatic doors corresponding to the burners that have successfully ignited, select an outlet pneumatic door that is the same as the preset number of openable burners and is adjacent to it, and open it. Based on the preset primary air volume and preset air-coal concentration, the coal mill is controlled for the coal pipe velocity and initial coal quantity, and the fuel quantity of a single burner nozzle and the total fuel quantity are determined. When the total fuel quantity reaches the preset fuel quantity threshold, the unopened outlet pneumatic valve is gradually opened according to the fuel quantity of a single burner nozzle. When all outlet pneumatic doors of the coal mill are opened, and the opening delay reaches a preset time threshold or the coal quantity of the coal mill reaches a preset coal quantity threshold, the low-oil ignition start mode of the coal mill is switched off.

2. The method according to claim 1, characterized in that, The boiler status parameters include boiler shutdown time, main steam pressure, and temperature parameters.

3. The method according to claim 2, characterized in that, The step of determining the coal mill start-up mode based on the acquired boiler status parameters includes: The boiler shutdown time in the boiler status parameters is compared with the preset shutdown time to determine the coal mill start-up mode; wherein, the coal mill start-up mode includes low oil ignition start-up mode, low oil ignition mode and normal mode.

4. The method according to claim 1, characterized in that, After controlling the pulverized coal pipe velocity and initial coal quantity of the coal mill, and determining the fuel quantity at a single burner nozzle and the total fuel quantity, the method further includes: By using a preset dynamic separator frequency, the amount of coal returned from the coal mill is increased, and the loading force of the coal mill is controlled by using the opening of the overflow valve, so as to keep the amount of coal stored inside the coal mill within a preset range. Increase the amount of fuel in the coal mill according to its heating and pressurization rate.

5. A coal mill output control device, characterized in that, The device includes: The start-up mode module is used to determine the start-up mode of the coal mill based on the acquired boiler status parameters. If the start-up mode of the coal mill is the low-oil ignition start-up mode, the valve action test is performed on all the outlet pneumatic valves of the coal mill to obtain the test results. The pilot ignition module is used to conduct a low-oil ignition test on all the burners corresponding to the outlet pneumatic valves of the coal mill if the test result shows that the valve operation is normal, and to determine the number of burners that are successfully ignited. The pneumatic door selection module is used to select, and open, the outlet pneumatic door that is the same as and adjacent to the preset number of openings among the outlet pneumatic doors corresponding to the successfully ignited burners if the number of burners that have successfully ignited is not less than the preset number of openings. The fuel quantity module is used to control the powder tube speed and initial coal quantity of the coal mill according to the preset primary air volume and preset air-coal concentration, and to determine the fuel quantity of a single burner nozzle and the total fuel quantity. The pneumatic door opening module is used to gradually open the unopened outlet pneumatic door according to the fuel quantity of a single burner nozzle when the total fuel quantity reaches a preset fuel quantity threshold. The mode cut-off module is used to cut off the low-oil ignition start-up mode of the coal mill when all the outlet pneumatic doors of the coal mill are open and the opening delay reaches a preset time threshold or the coal quantity of the coal mill reaches a preset coal quantity threshold.

6. The apparatus according to claim 5, characterized in that, The boiler status parameters include boiler shutdown time, main steam pressure, and temperature parameters.

7. The apparatus according to claim 6, characterized in that, The start-up mode module is also used to compare the boiler shutdown time in the boiler status parameters with the preset shutdown time to determine the coal mill start-up mode; wherein, the coal mill start-up mode includes low-oil ignition start-up mode, low-oil ignition mode and normal mode.

8. The apparatus according to claim 5, characterized in that, The device further includes: The loading force module is used to increase the amount of coal returned from the coal mill by using a preset dynamic separator frequency, and to control the loading force of the coal mill by using the opening of the overflow valve, so as to keep the amount of coal stored inside the coal mill within a preset range. The fuel supply module is used to increase the amount of fuel in the coal mill according to the rate of temperature and pressure increase of the coal mill.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method according to any one of claims 1 to 4.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that enables a computer to execute the method according to any one of claims 1 to 4.

11. A computer program product, comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the method according to any one of claims 1 to 4.

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