A control method and system for a coal mill separator in a direct-fired pulverizing system.

Abstract

This invention discloses a control method and system for a coal mill separator in a direct-fired pulverizing system. The method includes: automatically controlling the coal mill separator speed using a first preset formula, maintaining a constant separator speed while the coal feed rate fluctuates within a certain range; and adjusting the separator speed when the coal feed rate exceeds a certain threshold. The method calculates the reverse change in the coal mill separator speed based on the difference between the target load and the actual load of the generator set, and a second preset formula. This reverse change is then superimposed on the coal mill separator speed, causing the separator speed to automatically rise and fall in the reverse direction when the unit load changes. This invention can improve boiler load response speed and unit load regulation accuracy, and also prevent boiler main reheat steam temperature from exceeding the limit. It reduces frequent fluctuations in the current of the coal mill separator drive device, lowers the average current value, and is beneficial for energy saving. Furthermore, it reduces wear on the separator drive belt and increases the service life of the separator drive device.

Description

Technical Field

[0001] This invention relates to the technical field of combustion adjustment in coal-fired boilers, and more particularly to a control method and system for a coal mill separator in a direct-fired pulverizing system. Background Technology

[0002] Currently, power plant coal-fired boilers using direct-fired pulverizing systems have raw coal entering the boiler furnace for combustion. The relationship between the separator speed and coal feed rate in this system is as follows: the separator speed is a linear function of the coal feed rate, and changes in separator speed are directly proportional to the coal feed rate. However, power plant coal-fired boilers using direct-fired pulverizing systems face the following problems during dynamic load adjustments:

[0003] 1. The initial load response is slow, the feedwater increases rapidly while the fuel increases slowly, resulting in a sudden drop in the main reheat steam temperature;

[0004] 2. The load response is slow in the initial stage of load reduction, the feedwater is reduced quickly while the fuel is reduced slowly, resulting in the main reheat steam temperature exceeding the limit.

[0005] 3. The coal mill separator consumes a lot of electricity, and the separator and drive mechanism wear out quickly and are prone to failure.

[0006] The main reasons for problems 1 and 2 above are that during the dynamic process of boiler load increase and decrease, the fuel (raw coal) increase and decrease response of the direct-fired pulverizing system has a delayed characteristic. When the fuel (raw coal) increase command is sent to the coal feeder, the coal feeder responds quickly. However, after the raw coal enters the coal mill, it needs to be ground into pulverized coal before entering the furnace through the primary air duct. The coal storage inside the coal mill is an important factor causing the fuel response delay: when the coal quantity increases, the speed of the separator at the coal mill outlet also increases accordingly, resulting in increased resistance at the coal mill outlet. This causes a short-term increase in the coal storage inside the coal mill, resulting in the actual increase in fuel in the furnace being less than the command. Conversely, when the coal quantity decreases, the coal storage inside the coal mill enters the furnace, resulting in the actual decrease in fuel in the furnace being less than the command. The main reason for problem 3 is the frequent fluctuations in the speed of the coal mill separator. Summary of the Invention

[0007] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0008] In view of the aforementioned existing problems, the present invention is proposed.

[0009] Therefore, the purpose of this invention is to provide a control method for the coal mill separator in a direct-fired pulverizing system, which solves the problems of slow load increase / decrease speed of coal-fired boilers in power plants, large fluctuations in main and reheat steam parameters, and frequent fluctuations in the inverter current of the coal mill separator in current direct-fired pulverizing systems.

[0010] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0011] In a first aspect, embodiments of the present invention provide a control method for a coal mill separator in a direct-fired pulverizing system, comprising:

[0012] Calculate and control the rotational speed of the coal mill separator;

[0013] Among them, the speed of the coal mill separator is calculated by the first preset formula. When the coal feed rate fluctuates within a certain range, the speed of the coal mill separator remains unchanged. When the coal feed rate exceeds a certain threshold, the speed of the separator is increased or decreased.

[0014] Among them, the reverse change in the speed of the coal mill separator is calculated by the second preset formula based on the difference between the target load of the generator set and the actual load.

[0015] The reverse change is superimposed on the rotational speed of the coal mill separator to obtain the superimposed rotational speed, and the superimposed rotational speed is used to control the coal mill separator so that the rotational speed of the coal mill separator automatically rises and falls in the reverse direction when the unit load changes.

[0016] As described in this invention, the control method for the coal mill separator in a direct-fired pulverizing system includes: calculating the coal mill separator speed using a first preset formula; maintaining the coal mill separator speed constant when the coal feed rate fluctuates within a certain range; and controlling the increase or decrease of the separator speed when the coal feed rate exceeds a certain threshold. This includes calculating the coal mill separator speed based on the coal feed rate using the first preset formula, and summing the calculated coal mill separator speed with a manually set bias value to obtain an output value.

[0017] As described in the direct-fired pulverizing system coal mill separator control method of the present invention, the bias value includes 0, positive numbers and negative numbers, and its function is to increase or decrease the speed of all calculated coal mill separators by a certain value.

[0018] As a control method for the coal mill separator in a direct-fired pulverizing system according to the present invention, wherein: the first preset formula calculates the coal mill separator speed based on the coal feed rate, including...

[0019] Let the minimum coal feed rate X1 of the coal feeder be m, the corresponding output of F1(x) be a, the maximum coal feed rate be n, and the coal feed rate from m to n be divided into i equal parts, each part is denoted as r, i.e. r = (nm) / i. For every increase of r in the coal feed rate, the corresponding output of F1(x) increases by k.

[0020] The first preset formula F1(x) is a piecewise function:

[0021] m≥X1>0 F1(x)=a

[0022] m+ir+1≥X1>m+ir F1(x)=k(X1-m-ir)+a+ik

[0023] m+ir+r≥X1>m+ir+1F1(x)=a+ik

[0024] Where i = 0, 1, 2, 3, ... i, m, i, r, a, and k are constants, m is the minimum coal feed rate, n is the maximum coal feed rate, i is the number of equal parts between the minimum and maximum coal feed rates, r is the value of each of the aforementioned equal parts, i.e., r = (nm) / i, a is the separator speed corresponding to the minimum coal feed rate, and k is the increase in separator speed. The above constants can be selected according to the actual production situation to obtain the optimal value.

[0025] As described in the present invention, the control method for the coal mill separator in a direct-fired pulverizing system includes: calculating the reverse change in the coal mill separator speed based on the difference between the target load and the actual load of the generator set, and a second preset formula.

[0026] The reverse change is the change in the rotational speed of the coal mill separator.

[0027] If the difference is positive, it indicates an increase in load; if the reverse change is negative, it indicates a decrease in separator speed.

[0028] If the difference is negative, it indicates a load reduction; if the reverse change is positive, it indicates an increase in the separator speed.

[0029] Let X2 be the difference between the target load and the actual load of the generator set. The formula for calculating the reverse change in the speed of the coal mill separator using the second preset formula F2(X) is as follows:

[0030] The second preset formula F2(X) is a piecewise function:

[0031] X2<-c-1 F2(X)=d

[0032] -c-1≤X2≤-c F2(X)=-d(X2+c)

[0033] -c <X2<c F2(X)=0

[0034] c≤X²≤c+1 F²(X)=-d(X²-c)

[0035] X2>c+1 F2(X)=-d

[0036] Wherein, c and d are constants, c > 0 and d > 0. c represents a threshold value. When the load change amplitude is less than c, the change amount of the separator rotation speed is 0. d is the change amplitude of the separator rotation speed. The optimal values of c and d are selected according to the actual production situation.

[0037] As the control method for the mill separator in the direct-fired pulverized coal system of the present invention, further comprising:

[0038] When the difference X2 between the target load and the actual load of the generating set satisfies the condition of -c < X2 < c, the reverse change amount of the mill separator rotation speed is 0;

[0039] If the condition X2 > c is satisfied, the reverse change amount of the mill separator rotation speed is -d;

[0040] If the condition X2 < -c is satisfied, the reverse change amount of the mill separator rotation speed is d.

[0041] In a second aspect, an embodiment of the present invention provides a control system for the mill separator in a direct-fired pulverized coal system, including:

[0042] The first preset formula calculates the rotation speed of the mill separator according to the coal feeding amount. The calculated rotation speed of the mill separator and an artificially set offset value are both input into the first summing module for summation to obtain an output value;

[0043] Using the switching instruction of the switching module, select one of the automatic and manual control modes of the mill separator rotation speed and obtain the corresponding output result;

[0044] Input the output result of the switching module into the speed limiting module. According to the difference between the target load and the actual load of the generating set, calculate the reverse change amount of the mill separator rotation speed through the second preset formula and input it into the second summing module for summation;

[0045] The second summing module outputs the summation result and uses this output result as the final instruction to control the mill separator rotation speed.

[0046] As the control system for the mill separator in the direct-fired pulverized coal system of the present invention, wherein: when switching to the manual mode, the output result of the switching module is an artificially set separator rotation speed value;

[0047] When switching to the automatic mode, the output result of the switching module is the output value of the first summing module.

[0048] In a third aspect, an embodiment of the present invention provides a computing device, including:

[0049] A memory and a processor;

[0050] The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the one or more programs are executed by the one or more processors, the one or more processors implement a coal mill separator control method for a direct-fired pulverizing system as described in any embodiment of the present invention.

[0051] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the aforementioned method for controlling a coal mill separator in a direct-fired pulverizing system.

[0052] The beneficial effects of this invention are as follows: By controlling the rotational speed of the coal mill separator to adjust in reverse according to changes in boiler load, this invention allows fuel to enter the furnace more quickly when the boiler load is increased and to decrease fuel more quickly when the load is reduced. Therefore, it can improve the boiler load response speed and the accuracy of unit load regulation. It can also reduce the fluctuation range of main and reheat steam temperature during boiler load increases and decreases, preventing overheating of main and reheat steam temperature when the coal mill feed rate is high and the load is reduced. Furthermore, by changing the control function formula of the coal mill separator rotational speed, it reduces frequent fluctuations in the current of the separator drive device caused by frequent fluctuations in the coal feed rate command, lowering the average current and contributing to energy saving. It can also reduce the alternating stress of the separator transmission mechanism, reduce wear on the separator drive belt, and increase the service life of the separator drive device. Attached Figure Description

[0053] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0054] Figure 1 This is a schematic diagram of the first preset formula for the control method of the coal mill separator in the direct-fired pulverizing system of the present invention.

[0055] Figure 2 This is a schematic diagram of the second preset formula for the control method of the coal mill separator in the direct-fired pulverizing system of the present invention.

[0056] Figure 3 This is a control logic diagram of the coal mill separator in the direct-fired pulverizing system control method of the present invention.

[0057] Figure 4 This is a diagram of the existing separator speed function in the direct-fired pulverizing system coal mill separator control method of the present invention. Detailed Implementation

[0058] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0059] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0060] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0061] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include the three-dimensional spatial dimensions of length, width, and depth.

[0062] Example 1

[0063] Reference Figures 1-3 An embodiment of the present invention provides a control method for a coal mill separator in a direct-fired pulverizing system, comprising:

[0064] S1: The pulverizer separator speed is calculated using a first preset formula. When the coal feed rate fluctuates within a certain range, the pulverizer separator speed remains constant. When the coal feed rate exceeds a certain threshold, the separator speed is adjusted accordingly. It should be noted that:

[0065] The first preset formula calculates the mill separator speed based on the coal feed rate. The calculated mill separator speed is then summed with a manually set bias value to obtain the output value.

[0066] The bias value includes 0, positive, and negative numbers, and its function is to increase or decrease the calculated speed of all coal mill separators by a certain amount.

[0067] The first preset formula calculates the mill separator speed based on the coal feed rate, including...

[0068] Let the minimum coal feed rate X1 of the coal feeder be m, the corresponding output of F1(x) be a, the maximum coal feed rate be n, and the coal feed rate from m to n be divided into i equal parts, each part is denoted as r, i.e. r = (nm) / i. For every increase of r in the coal feed rate, the corresponding output of F1(x) increases by k.

[0069] The first preset formula F1(x) is a piecewise function:

[0070] m≥X1>0 F1(x)=a

[0071] m+ir+1≥X1>m+ir F1(x)=k(Xm-ir)+a+ik

[0072] m+ir+r≥X1>m+ir+1F1(x)=a+ik

[0073] Where i = 0, 1, 2, 3, ... i, m, i, r, a, and k are constants, m is the minimum coal feed rate, n is the maximum coal feed rate, i is the number of equal parts between the minimum and maximum coal feed rates, r is the value of each of the aforementioned equal parts, i.e., r = (nm) / i, a is the separator speed corresponding to the minimum coal feed rate, and k is the increase in separator speed. The above constants can be selected according to the actual production situation to obtain the optimal value.

[0074] S2: The reverse change in the mill separator speed is calculated based on the difference between the target load and the actual load of the generator set, and the second preset formula. It should be noted that:

[0075] The inverse change is the change in the rotational speed of the coal mill separator;

[0076] If the difference is positive, it indicates an increase in load; if the reverse change is negative, it indicates a decrease in separator speed.

[0077] If the difference is negative, it indicates a load reduction; if the reverse change is positive, it indicates an increase in the separator speed.

[0078] Let X2 be the difference between the target load and the actual load of the generator set. The formula for calculating the reverse change in the speed of the coal mill separator using the second preset formula F2(X) is as follows:

[0079] The second preset formula F2(X) is a piecewise function:

[0080] X2<-c-1 F2(X)=d

[0081] -c-1≤X2≤-c F2(X)=-d(X+c)

[0082] -c <X2<c F2(X)=0

[0083] c≤X²≤c+1 F²(X)=-d(Xc)

[0084] X2>c+1 F2(X)=-d

[0085] Among them, c and d are constants, where c > 0 and d > 0. c represents a threshold value. When the load change amplitude is less than c, the change amount of the separator rotation speed is 0. d is the change amplitude of the separator rotation speed. The optimal values of c and d are selected according to the actual production situation.

[0086] When the difference X2 between the target load and the actual load of the generator set satisfies the condition of -c < X2 < c, the reverse change amount of the mill separator rotation speed is 0;

[0087] If the condition X2 > c is satisfied, the reverse change amount of the mill separator rotation speed is -d;

[0088] If the condition X2 < -c is satisfied, the reverse change amount of the mill separator rotation speed is d.

[0089] And as Figures 1-2 shown, the first preset formula provided by us, that is, the separator rotation speed preset formula, when the coal feeding amount X fluctuates within a certain range, the separator rotation speed Y remains unchanged. It can filter out the separator rotation speed fluctuations caused by frequent bidirectional fluctuations of the coal feeding amount, reduce the fluctuation amplitude of the separator current up and down, improve the service life of the separator and the driving mechanism. At the same time, it can protect the separator drive belt and reduce the damage caused by frequent changes in the belt stress. The second preset formula provided by the present invention, that is, the preset formula for the separator rotation speed rise and fall corresponding to the load change amount, can accurately control the rise and fall of the separator rotation speed according to the load change amount.

[0090] In the control logic, the set values of the separator rotation speed setting function F1(X) and the separator rotation speed rise and fall function F2(X) modules can be modified according to the application situation.

[0091] Even if the separator rotation speed control is switched to manual control, the separator rotation speed rise and fall logic still works.

[0092] As Figure 3 shown, this embodiment also provides a mill separator control system for a direct-fired pulverized coal system, including:

[0093] Calculate the mill separator rotation speed r1 according to the coal feeding amount X1 of the coal feeder in the pulverized coal system through the preset formula F1(x); this rotation speed is used as one input of the first summing module 100;

[0094] According to needs, a bias value r2 of the separator rotation speed can be artificially set as another input of the above first summing module 100 (r2 is a positive number for positive bias, a negative number for negative bias, and 0 for no bias);

[0095] The output r3 of the above first summing module 100 is r3 = r1 + r2, and r3 is used as one of the inputs of the switching module 200;

[0096] A separator speed offset value A can be manually set as needed, which is also one of the inputs to the aforementioned switching module 200;

[0097] When the switching module 200 is switched to manual mode, the switching module 200 outputs r4 = A; when switched to automatic mode, the switching module 200 outputs r4 = r3.

[0098] The output r4 of the aforementioned switching module 200 is used as the input of the speed limiting module 300, and the output r5 of the speed limiting module 300 is used as one input of the second summing module 400;

[0099] The change X2 (positive or negative) of the difference between the unit load command and the actual load is used to calculate the change r6 of the speed of the separator that needs to be increased (positive) and decreased (negative) through the predetermined formula F2(x). r6 is used as another input of the second summing module 400.

[0100] The output of the second summing module 400, r7 = r5 + r6, is used as the final speed command to control the speed of the coal mill separator.

[0101] This embodiment also provides a computing device applicable to a control method for a coal mill separator in a direct-fired pulverizing system, including:

[0102] The system includes a memory and a processor. The memory stores computer-executable instructions, and the processor executes these instructions to implement a control method for a coal mill separator in a direct-fired pulverizing system, as described in the above embodiments.

[0103] The computer device can be a terminal, comprising a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0104] This embodiment also provides a storage medium storing a computer program that, when executed by a processor, implements a control method for a coal mill separator in a direct-fired pulverizing system as proposed in the above embodiments.

[0105] The storage medium proposed in this embodiment and the data storage method proposed in the above embodiment belong to the same inventive concept. Technical details not fully described in this embodiment can be found in the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0106] Example 2

[0107] Reference Figure 4 This embodiment is another embodiment of the present invention. Unlike the first embodiment, this embodiment provides a verification test of the control method for the coal mill separator in a direct-fired pulverizing system, and verifies and explains the technical effects adopted in this method.

[0108] The relationship between the rotational speed of the coal mill separator and the coal feed rate in existing coal-fired power plant boilers using direct-fired pulverizing systems is as follows: Figure 4 As shown, the separator speed is a linear function of the coal feed rate, and the increase or decrease of the separator speed varies with the coal feed rate.

[0109] The following problems exist in the dynamic process of load increase and decrease of coal-fired boilers in power plants using direct-fired pulverizing systems:

[0110] 1. The initial load response is slow, the feedwater increases rapidly while the fuel increases slowly, resulting in a sudden drop in the main reheat steam temperature;

[0111] 2. The load response is slow in the initial stage of load reduction, the feedwater is reduced quickly while the fuel is reduced slowly, resulting in the main reheat steam temperature exceeding the limit.

[0112] The main reason for the above problems is that during the dynamic process of boiler load increase and decrease, the fuel (raw coal) increase and decrease response of the direct-fired pulverizing system exhibits a delayed characteristic. When the fuel (raw coal) increase command is sent to the coal feeder, the feeder responds quickly. However, after the raw coal enters the pulverizer, it needs to be ground into pulverized coal before entering the furnace through the primary air duct. The coal residue inside the pulverizer is a significant factor causing the fuel response delay: when the coal quantity increases, the separator speed at the pulverizer outlet also increases accordingly, leading to increased resistance at the pulverizer outlet. This causes a short-term increase in the coal residue inside the pulverizer, resulting in the actual increase in fuel in the furnace being less than the commanded amount. Conversely, when the coal quantity decreases, the coal residue inside the pulverizer enters the furnace, resulting in the actual decrease in fuel in the furnace being less than the commanded amount. The process of boiler load increase and decrease is as follows:

[0113] When the load is increased: the coal feed rate increases, the separator speed increases, the resistance of the coal mill increases, the coal stored in the coal mill increases, the amount of coal entering the furnace is less than the command, the boiler side load response is slow and the main reheat steam temperature drops.

[0114] When the load is reduced: the coal feed rate decreases, the separator speed decreases, the coal mill resistance decreases, the coal stored in the coal mill decreases, the amount of coal entering the furnace is greater than the command, the boiler side slows down the load reduction response and the main reheat steam temperature exceeds the limit.

[0115] As shown in Tables 1 and 2, the first preset formula provided by us is the separator speed preset formula F1(x), and the second preset formula is the load change corresponding to the separator speed rise and fall preset formula F2(x).

[0116] Table 1: Preset formula for separator speed F1(x)

[0117]

[0118]

[0119] Table 2: Preset formula F2(x) for separator speed increase / decrease corresponding to load change

[0120] X Load Change (MW) F2(x)(rpm) X<-15 F2(x) = 80 -15≤X≤-14 F2(x) = -80(X+15) + 80 -14<X<14 F2(x)=0 14≤X≤15 F2(x)=-80(X-15)-80 15<X F2(x) = -80

[0121] The advantages of the preset formula F1(X) of the present invention compared to the original preset formula in Table 1 are: when the coal feed X fluctuates within a certain range, the separator speed Y remains unchanged, which can filter out the separator speed fluctuation caused by frequent bidirectional fluctuations in the coal feed. The function is to reduce the fluctuation range of the separator current, improve the life of the frequency converter, and at the same time protect the separator drive belt and reduce the damage caused by frequent changes in belt force.

[0122] The preset formula F2(X) for the change in load corresponding to the increase or decrease in separator speed in Table 2 has the following characteristics: if the difference between the target load and the actual load is >14MW, the output value is -80rpm; if the difference between the target load and the actual load is <-14MW, the output value is +80rpm.

[0123] The comparison results between the existing technology and the technology using the present invention are shown in Tables 3 and 4 below.

[0124] Table 3: Comparison of main and reheat steam temperature fluctuations in boilers using existing technology and the present invention

[0125]

[0126] As can be seen from Table 3, after adopting the present invention, the fluctuation range of boiler main steam temperature and reheat steam temperature during load changes is significantly reduced, which is beneficial to the stability of the unit's main and reheat steam temperatures.

[0127] Table 4: Comparison of current of coal mill separators using existing technology and the present invention

[0128]

[0129]

[0130] As can be seen from Table 4, after adopting the present invention, the current fluctuation amplitude of the coal mill separator is significantly reduced, and the average current of the separator is significantly decreased, which is beneficial to energy saving.

[0131] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A control method for a coal mill separator in a direct-fired pulverizing system, characterized in that: include, Calculate and control the rotational speed of the coal mill separator; The process involves calculating the rotational speed of the coal mill separator using a first preset formula. When the coal feed rate fluctuates within a certain range, the rotational speed of the coal mill separator remains constant. When the coal feed rate exceeds a certain threshold, the rotational speed of the coal mill separator is controlled to increase or decrease. This includes: calculating the rotational speed of the coal mill separator based on the coal feed rate using the first preset formula; and summing the calculated rotational speed of the coal mill separator with a manually set bias value to obtain an output value. The first preset formula calculates the mill separator speed based on the coal feed rate, including: Let the minimum coal feed rate X1 of the coal feeder be m, the corresponding output of F1(x) be a, the maximum coal feed rate be n, and the coal feed rate from m to n be divided into i equal parts, each part is denoted as r, i.e. r = (nm) / i. For every increase of r in the coal feed rate, the corresponding output of F1(x) increases by k. The first preset formula F1(x) is a piecewise function: m≥X1>0F1(x)=a m+ir+1≥X1>m+ir F1(x)=k(X1-m-ir)+a+ik m+ir+r≥X1>m+ir+1F1(x)=a+ik Where i = 0, 1, 2, 3, ... i, m, i, r, a, k are constants, m is the minimum coal feed rate, n is the maximum coal feed rate, i is the number of equal parts between the minimum and maximum coal feed rates, r is the value of each of the aforementioned equal parts, i.e., r = (nm) / i, a is the mill separator speed corresponding to the minimum coal feed rate, and k is the increase in mill separator speed. The above constants can be selected according to the actual production situation to obtain the optimal value. Specifically, based on the difference between the target load and the actual load of the generator set, the reverse change in the speed of the coal mill separator is calculated using a second preset formula, including: The reverse change is the change in the rotational speed of the coal mill separator. If the difference is positive, it indicates an increase in load; if the reverse change is negative, it indicates a decrease in the speed of the coal mill separator. If the difference is negative, it indicates a load reduction; if the reverse change is positive, it indicates an increase in the speed of the coal mill separator. Let X2 be the difference between the target load and the actual load of the generator set. The formula for calculating the reverse change in the speed of the coal mill separator using the second preset formula F2(X) is as follows: The second preset formula F2(X) is a piecewise function: X2<-c-1F2(X)=d -c-1≤X2≤-c F2(X)=-d(X2+c) -c <X2<c F2(X)=0 c≤X²≤c+1F²(X)=-d(X²-c) X2>c+1F2(X)=-d Where c and d are constants and c>0 and d>0, c represents a threshold value, when the load change is less than c, the change in the speed of the coal mill separator is 0, and d is the change in the speed of the coal mill separator. The optimal values ​​of c and d are selected according to the actual production situation. The reverse change is superimposed on the rotational speed of the coal mill separator to obtain the superimposed rotational speed, and the superimposed rotational speed is used to control the coal mill separator so that the rotational speed of the coal mill separator automatically rises and falls in the reverse direction when the unit load changes.

2. The control method for the coal mill separator in a direct-fired pulverizing system as described in claim 1, characterized in that: The offset value includes 0, positive numbers, and negative numbers, and its function is to increase or decrease all calculated speeds of the coal mill separator by a certain value.

3. The control method for the coal mill separator in a direct-fired pulverizing system as described in claim 2, characterized in that: It also includes When the difference X2 between the target load and the actual load of the generator set satisfies the condition -c < X2 < c, the reverse change amount of the speed of the coal mill separator is 0; If the condition X2 > c is satisfied, the reverse change amount of the speed of the coal mill separator is -d; If the condition X2 < -c is satisfied, the reverse change amount of the speed of the coal mill separator is d.

4. A control system for a coal mill separator in a direct-fired pulverizing system, comprising the method described in any one of claims 1-3, characterized in that, It includes The first preset formula calculates the speed of the coal mill separator according to the coal feeding amount. The calculated speed of the coal mill separator and an artificially set offset value are both input into the first summing module (100) for summation to obtain an output value; Using the switching instruction of the switching module (200), one of the automatic and manual control modes of the speed of the coal mill separator is selected to obtain the corresponding output result; The output result of the switching module (200) is input into the speed limiting module (300). According to the difference between the target load and the actual load of the generator set, the reverse change amount of the speed of the coal mill separator is calculated through the second preset formula and input into the second summing module (400) for summation; The second summing module (400) outputs the summation result and uses the output summation result as the final instruction to control the speed of the coal mill separator.

5. The coal mill separator control system of the direct-fired pulverizing system as described in claim 4, characterized in that: Using the switching instruction of the switching module (200), selecting one of the automatic and manual control modes of the speed of the coal mill separator to obtain the corresponding output result includes If it is selected to switch to the manual mode, the output result of the switching module (200) is an artificially set speed value of the separator; If it is selected to switch to the automatic mode, the output result of the switching module (200) is the output value of the first summing module (100).

6. A computing device, comprising: A memory and a processor; The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor, the steps of the direct-fired pulverized coal system coal mill separator control method according to any one of claims 1 to 3 are implemented.

7. A computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are executed by the processor, the steps of the direct-fired pulverized coal system coal mill separator control method according to any one of claims 1 to 3 are implemented.

Images