A method and system for evaluating the state of a medium-speed coal mill based on coal grinding unit consumption characteristics

Abstract

The present invention discloses a method and system for evaluating the state of a medium-speed coal mill based on the characteristics of coal mill unit consumption, and relates to the technical field of coal mill state evaluation, including collecting coal mill related data, analyzing the index change trend of the coal mill; constructing a statistical model and an optimization adjustment model, determining the normal range interval of unit consumption, loading pressure, and primary air pressure, and constructing a coal mill unit consumption degradation evaluation model and a roller wear calculation model; real-time monitoring of the coal mill operating state, evaluating the coal mill degradation and roller wear, providing adjustment suggestions and assisting in formulating maintenance strategies. The method of the present invention constructs a roller wear measurement model and an optimization adjustment model by counting the equipment operating time, the number of stone coal discharges, and the number of roller lifting and lowering times, to ensure that the coal mill always operates under the best working conditions, and by constructing a coal mill unit consumption degradation evaluation model and a roller wear calculation model, the operating reliability and economy of the coal mill are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mill status assessment, and in particular to a method and system for assessing the status of a medium-speed coal mill based on coal grinding unit consumption characteristics. Background Art

[0002] As one of the core equipment of coal-fired power plants, the operating status of medium-speed coal mills directly affects the reliability and economy of boilers and pulverizing systems. Since the 1980s, with the gradual development of condition monitoring and evaluation technology, equipment maintenance strategies have also gradually shifted from traditional "planned maintenance" to "condition-based maintenance". With the advancement of industrial automation and information technology, modern power plants have gradually applied digital means to monitor equipment status. By collecting and analyzing equipment operation data, equipment failures can be discovered and handled in a timely manner, thereby reducing unplanned downtime of equipment, optimizing maintenance strategies, and improving the economy and reliability of equipment operation.

[0003] However, although the existing technology has made certain progress in condition monitoring and equipment maintenance, there are still some shortcomings. The traditional coal mill condition assessment method mainly relies on manual statistics and monthly average unit consumption data. This method is not only time-consuming and labor-intensive, but also difficult to reflect the operating status of the coal mill in real time, resulting in the inability to timely warn and handle equipment failures. The existing condition monitoring system lacks effective comprehensive analysis of the multi-dimensional parameters of the coal mill (such as loading pressure, primary air pressure, etc.), and cannot provide accurate optimization and adjustment suggestions. For the assessment of roller wear, most methods require shutdown for manual measurement, and cannot achieve online real-time monitoring, which increases the complexity and uncertainty of maintenance work. In addition, in the process of dealing with coal mill unit consumption degradation and roller wear, the existing technology has relatively simple data cleaning and model building methods, which cannot adapt to complex and changeable working conditions. Therefore, the existing technology still has a lot of room for improvement in the real-time, accuracy and intelligence of coal mill condition assessment. Summary of the invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] Therefore, the technical problem solved by the present invention is: the existing coal mill status assessment method has the problems of poor real-time performance, insufficient comprehensive analysis capability, and inability to realize online real-time monitoring of grinding roller wear, as well as how to realize real-time monitoring and accurate assessment of the coal mill operating status.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: a method for evaluating the state of a medium-speed coal mill based on the unit consumption characteristics of coal mill, comprising collecting relevant data of the coal mill and analyzing the index change trend of the coal mill; constructing a statistical model and an optimization adjustment model to determine the normal range of unit consumption, loading pressure, and primary air pressure, and constructing a coal mill unit consumption degradation evaluation model and a roller wear calculation model; real-time monitoring of the coal mill operating status, evaluating the coal mill degradation and roller wear, providing adjustment suggestions and assisting in formulating maintenance strategies.

[0007] As a preferred scheme of the medium-speed coal mill status assessment method based on the coal grinding unit consumption characteristics described in the present invention, the coal mill related data includes coal mill motor current, voltage, gravel coal discharge door status, hydraulic loading force, grinding roller lifting status, coal mill maintenance record, grinding roller measurement and replacement data.

[0008] As a preferred solution of the medium-speed coal mill state evaluation method based on the coal mill unit consumption characteristics of the present invention, the index change trend analysis includes calculating the coal mill unit consumption, which is expressed as:

[0009]

[0010] Among them, E c is the coal grinding unit consumption of the coal mill, I is the coal mill current, V is the coal mill voltage, P F is the power factor, F is the coal feed rate. Based on historical data, the relationship between the unit consumption of the coal mill and the coal feed rate is analyzed through a scatter plot. The unit consumption of the coal mill is negatively correlated with the coal feed rate. When different coal mills grind different coal qualities, there are differences in the upper and lower ranges of the unit consumption under the same coal amount. The changing trend of the unit consumption with the operating time is analyzed through time series distribution. The operating time is positively correlated with the unit consumption of the coal mill.

[0011] As a preferred solution of the method for evaluating the state of a medium-speed coal mill based on the coal mill unit consumption characteristics described in the present invention, wherein: the construction of a statistical model and an optimization adjustment model includes counting the equipment operating time, the number of stone coal discharges and the number of roller lifting times through a counter, calculating the amount of roller wear through the operating time, and correcting the coal mill state evaluation, assisting in the judgment of coal quality changes through the number of stone coal discharges, and evaluating the roller wear through the number of roller lifting times; respectively extracting historical data related to unit consumption, loading pressure, primary air pressure and coal feeding amount for analysis to construct an optimization adjustment model, cleaning the data during the period of discrete data addition and subtraction of load in the historical data, taking the data fitting slope of the most recent ten seconds as the rate of change of coal feeding amount, fitting the upper and lower edge lines based on the cleaned data, obtaining the upper and lower limits of the normal range of coal mill unit consumption, loading pressure and primary air pressure, and comparing the real-time parameters in the corresponding interval band to determine whether it is currently in a normal state. When the coal mill unit consumption, loading pressure and primary air pressure parameters deviate from the interval band corresponding to the normal state, notifying the operating personnel to perform real-time optimization and adjustment to adjust the coal mill unit consumption to within the normal range.

[0012] As a preferred solution of the method for evaluating the state of a medium-speed coal mill based on the coal mill unit consumption characteristics of the present invention, the coal mill unit consumption degradation evaluation model includes comparing the distribution data of the coal mill unit consumption under different coal amounts in different months based on the coal mill unit consumption data, drawing a distribution curve of unit consumption-coal feeding amount, and constructing a coal mill unit consumption degradation evaluation model under different states by analyzing the unit consumption characteristics of the coal mill under different operating stages. The coal feeding amount in the model is x, x∈[30,60], the unit consumption in the model is y, and the unit consumption degradation state includes a normal stage, a slight wear stage, an abnormal wear stage and a severe wear stage; the coal mill unit consumption degradation evaluation model under the normal stage is expressed as:

[0013] 0.0016x 2 -0.2555x+16.414 <y≤0.0021x 2 -0.3124x+18.171

[0014] The unit consumption degradation evaluation model of coal mill under the slight wear stage is expressed as:

[0015] 0.0021x 2 -0.3124x+18.171 <y≤0.0025x 2 -0.3634x+19.771

[0016] The unit consumption degradation evaluation model of coal mill under abnormal wear stage is expressed as:

[0017] 0.0025x 2-0.3634x+19.771 <y≤0.003x 2 -0.4185x+21.41

[0018] The unit consumption degradation evaluation model of coal mill under severe wear stage is expressed as:

[0019] y>0.003x 2 -0.4185x+21.41

[0020] Based on the coal mill unit consumption degradation evaluation model under different conditions, the unit consumption degradation evaluation is carried out, and the coal feed rate and unit consumption are substituted respectively to obtain the unit consumption point P(x n ,y n ), judge the state of each single consumption point, take the degradation state where the single consumption point falls in the largest number as the current single consumption degradation state of the coal mill, when the largest number of degradation states is greater than or equal to two, take the most serious state as the output result.

[0021] As a preferred solution of the method for evaluating the state of a medium-speed coal mill based on the coal grinding unit consumption characteristics described in the present invention, the roller wear calculation model includes evaluating the state of roller wear, calculating the wear rate, the wear rate μ at different stages = wear rate factor × average wear rate of the coal mill, average wear rate of the coal mill = roller wear amount within the statistical time / cumulative running time, and the wear rate is divided into three stages, including the initial running-in stage, the stable wear stage, and the severe wear stage; when the wear amount is greater than 0 mm and less than 15 mm, the wear rate is in the initial running-in stage, and the wear rate factor is 1.53; when the wear amount is greater than or equal to 15 mm and less than 5 When the wear amount is greater than or equal to 50 mm, the wear rate is in the severe wear stage, and the wear rate factor is 1.66; the coal mill running time, roller wear, wear rate, and average wear rate are statistically analyzed, and the wear rate factor of each measurement cycle = wear rate in the measurement cycle / average wear rate; the real-time wear rate of the coal mill roller is corrected based on the real-time unit consumption of the coal mill. When the ratio of the real-time unit consumption of the coal mill to the predicted unit consumption is greater than 1, the current wear rate is adjusted to the wear rate of the current corresponding wear stage × the ratio of the real-time unit consumption of the coal mill to the expected unit consumption.

[0022] As a preferred scheme of the medium-speed coal mill state assessment method based on the coal mill unit consumption characteristics described in the present invention, wherein: the assessment of coal mill degradation and grinding roller wear includes real-time monitoring of whether the current coal mill coal mill consumption deviates from the normal range based on the coal mill unit consumption online optimization adjustment model. When it deviates from the normal range, the adjustment direction of the relevant adjustable performance parameters is given and the parameter changes of the adjustment process are tracked visually in real time to assist in the control of the adjustment process; when the coal mill unit consumption degradation state is in the severe wear stage and the wear amount is greater than or equal to 60 mm, the monitoring system issues a high-risk warning and notifies the operating personnel to immediately conduct on-site inspection of the coal mill and troubleshoot equipment faults.

[0023] Another object of the present invention is to provide a medium-speed coal mill state assessment system based on the coal mill unit consumption characteristics, which can determine the normal range of unit consumption, loading pressure, and primary air pressure by constructing statistical models and optimization adjustment models, and construct a coal mill unit consumption degradation assessment model and a roller wear calculation model, thereby solving the problem of low accuracy in current coal mill state assessment.

[0024] As a preferred solution of the medium-speed coal mill state assessment system based on the coal mill unit consumption characteristics described in the present invention, it includes: a trend analysis module, a model building module, and a state assessment module; the trend analysis module is used to collect coal mill related data and perform index change trend analysis of the coal mill; the model building module is used to construct a statistical model and an optimization adjustment model, determine the normal range of unit consumption, loading pressure, and primary air pressure, and construct a coal mill unit consumption degradation assessment model and a roller wear calculation model; the state assessment module is used to monitor the coal mill operating status in real time, evaluate the coal mill degradation and roller wear, provide adjustment suggestions and assist in formulating maintenance strategies.

[0025] A computer device includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement a method for evaluating the state of a medium-speed coal mill based on coal consumption characteristics.

[0026] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a method for evaluating the state of a medium-speed coal mill based on coal grinding unit consumption characteristics.

[0027] Beneficial effects of the present invention: The method for evaluating the state of a medium-speed coal mill based on the unit consumption characteristics of coal milling provided by the present invention collects relevant data of the coal mill and analyzes the index change trend of the coal mill, so as to identify abnormal changes in the operation of the coal mill and discover potential faults in time, thereby improving the reliability and economy of the operation of the coal mill. By counting the operating time of the equipment, the number of times the stone coal is discharged and the number of times the roller is lifted and lowered, a calculation model for the wear amount of the roller is constructed, and by analyzing the historical data of unit consumption, loading pressure, primary air pressure and coal feeding amount, an optimization adjustment model is constructed, and the historical data are used to calculate the wear amount of the roller. After cleaning the discrete data in the data, the normal range of unit consumption, loading pressure and primary wind pressure was obtained by fitting the upper and lower edge lines, thereby realizing accurate monitoring and optimization adjustment of the operating status of the coal mill, ensuring that the coal mill always operates under the best working conditions, reducing energy consumption, and improving operating efficiency. By constructing a coal mill unit consumption degradation evaluation model and a roller wear calculation model, the degradation state of the coal mill and the wear of the roller can be evaluated in real time, thereby improving the operating reliability and economy of the coal mill. The present invention achieves better results in terms of reliability, efficiency and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0029] Figure 1 An overall flow chart of a method for evaluating the state of a medium-speed coal mill based on coal grinding unit consumption characteristics is provided for the first embodiment of the present invention.

[0030] Figure 2 An overall flow chart of a medium-speed coal mill state assessment system based on coal grinding unit consumption characteristics is provided for the third embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0032] Example 1

[0033] Reference Figure 1 , which is an embodiment of the present invention, provides a method for evaluating the state of a medium-speed coal mill based on coal grinding unit consumption characteristics, comprising:

[0034] S1: Collect coal mill related data and analyze the index change trend of the coal mill.

[0035] Furthermore, the coal mill related data include coal mill motor current, voltage, gravel coal discharge door status, hydraulic loading force, roller lifting status, coal mill maintenance record, roller measurement and replacement data.

[0036] It should be noted that the trend analysis of index changes includes the calculation of coal mill unit consumption, which is expressed as:

[0037]

[0038] Among them, E c is the coal grinding unit consumption of the coal mill, I is the coal mill current, V is the coal mill voltage, P F is the power factor, F is the coal feed rate. Based on historical data, the relationship between the unit consumption of the coal mill and the coal feed rate is analyzed through a scatter plot. The unit consumption of the coal mill is negatively correlated with the coal feed rate. When different coal mills grind different coal qualities, there are differences in the upper and lower ranges of the unit consumption under the same coal amount. The changing trend of the unit consumption with the operating time is analyzed through time series distribution. The operating time is positively correlated with the unit consumption of the coal mill.

[0039] It should also be noted that the unit consumption of coal mill decreases with the increase of coal feed, and can be roughly distributed as a quadratic function. Different coal mills grind different coal qualities, which leads to differences in the upper and lower ranges of unit consumption under the same amount of coal. By collecting data such as current, voltage, stone coal discharge door status, hydraulic loading force, grinding roller lifting status, and maintenance records, comprehensive monitoring of the operating status of the coal mill is achieved. By analyzing these data, the relationship between the unit consumption of the coal mill and the coal feed, as well as the changing trend of the unit consumption with the running time can be revealed. These analysis results are helpful to understand the performance of the coal mill under different operating conditions, identify abnormal conditions, and warn of potential problems in advance, thereby optimizing the operating strategy, reducing unplanned shutdowns, and improving system reliability and economy.

[0040] S2: Construct statistical models and optimization adjustment models, determine the normal range of unit consumption, loading pressure, and primary air pressure, and construct a coal mill unit consumption degradation assessment model and a roller wear measurement model.

[0041] Furthermore, constructing a statistical model and an optimization adjustment model includes using a counter to count the equipment operating time, the number of pebble coal discharges, and the number of roller lifting times, calculating the roller wear through the operating time, and correcting the coal mill status assessment, using the number of pebble coal discharges to assist in the judgment of coal quality changes, and evaluating the roller wear through the number of roller lifting times; extracting historical data on unit consumption, loading pressure, primary air pressure, and coal feed rate for analysis to construct an optimization adjustment model, cleaning the data during the period of discrete data addition and subtraction in the historical data, taking the data fitting slope of the most recent ten seconds as the rate of change of coal feed rate, fitting the upper and lower edge lines based on the cleaned data, and obtaining the upper and lower limits of the normal range of coal mill unit consumption, loading pressure, and primary air pressure, and comparing the real-time parameters to the corresponding interval band to determine whether it is currently in a normal state, and when the coal mill unit consumption, loading pressure, and primary air pressure parameters deviate from the interval band corresponding to the normal state, notifying the operating personnel to perform real-time optimization and adjustment to adjust the coal mill unit consumption to within the normal range.

[0042] It should be noted that the coal mill unit consumption degradation assessment model includes comparing the distribution data of coal mill unit consumption under different coal amounts in different months based on the coal mill unit consumption data, drawing the distribution curve of unit consumption-coal feeding amount, and constructing the coal mill unit consumption degradation assessment model under different states by analyzing the unit consumption characteristics of the coal mill under different operation stages. The coal feeding amount in the model is x, x∈[30,60], the unit consumption in the model is y, and the unit consumption degradation states include normal stage, slight wear stage, abnormal wear stage and severe wear stage; the coal mill unit consumption degradation assessment model under the normal stage is expressed as:

[0043] 0.0016x 2 -0.2555x+16.414 <y≤0.0021x 2 -0.3124x+18.171

[0044] The unit consumption degradation evaluation model of coal mill under the slight wear stage is expressed as:

[0045] 0.0021x 2 -0.3124x+18.171 <y≤0.0025x 2 -0.3634x+19.771

[0046] The unit consumption degradation evaluation model of coal mill under abnormal wear stage is expressed as:

[0047] 0.0025x 2 -0.3634x+19.771 <y≤0.003x 2 -0.4185x+21.41

[0048] The unit consumption degradation evaluation model of coal mill under severe wear stage is expressed as:

[0049] y>0.003x 2 -0.4185x+21.41

[0050] Based on the coal mill unit consumption degradation evaluation model under different conditions, the unit consumption degradation evaluation is carried out, and the coal feed rate and unit consumption are substituted respectively to obtain the unit consumption point P(x n ,y n ), judge the state of each single consumption point, take the degradation state where the single consumption point falls in the largest number as the current single consumption degradation state of the coal mill, when the largest number of degradation states is greater than or equal to two, take the most serious state as the output result.

[0051] It should also be noted that the roller wear calculation model includes the evaluation of the roller wear state and the calculation of the wear rate. The wear rate μ at different stages = wear rate factor × average wear rate of the coal mill. The average wear rate of the coal mill = roller wear amount within the statistical time / cumulative running time. The wear rate is divided into three stages, including the initial running-in stage, the stable wear stage, and the severe wear stage. When the wear amount is greater than 0 mm and less than 15 mm, the wear rate is in the initial running-in stage, and the wear rate factor is 1.53; when the wear amount is greater than or equal to 15 mm and less than 50 mm, the wear rate is in the stable wear stage. The wear rate factor is 0.72; when the wear amount is greater than or equal to 50 mm, the wear rate is in the severe wear stage, and the wear rate factor is 1.66; the coal mill running time, roller wear amount, wear rate, and average wear rate are statistically analyzed, and the wear rate factor of each measurement cycle = wear rate in the measurement cycle / average wear rate; the real-time wear rate of the coal mill roller is corrected based on the real-time unit consumption of the coal mill. When the ratio of the real-time unit consumption of the coal mill to the predicted unit consumption is greater than 1, the current wear rate is adjusted to the wear rate of the current corresponding wear stage × the ratio of the real-time unit consumption of the coal mill to the expected unit consumption.

[0052] It should also be noted that the coal mill status assessment is mainly for the status assessment of the roller wear. If the roller wear exceeds a certain limit, the coal mill energy consumption will increase, the operation fluctuation will become larger, and it may even be impossible to grind the raw coal to the state required for boiler combustion, which is very likely to cause safety accidents. However, since the amount of roller wear can only be measured by stopping the mill and uncovering it, and the coal quality ground by different coal mills is also different, it is obviously unreasonable to conduct regular maintenance based on the traditional unified standard of 8000 hours of maintenance. Therefore, our invention aims to construct a model for online real-time measurement of coal mill roller wear, so as to It helps operation and maintenance personnel to have a more accurate control over the wear of the coal mill. The wear rate of the roller is different in different stages, which can be roughly divided into three stages. There is a big difference in the wear rate in the three stages. The wear rate is faster in the running-in stage, and gradually slows down in the stable wear stage. In the severe wear stage, the wear rate begins to accelerate. The wear range of the three wear stages is preliminarily divided. The fastest wear rate is the period from 0mm-11mm, and the wear from 0mm-17mm slows down a bit, indicating that 17mm has entered the stable wear stage. 5mm is the dividing point for entering the stable wear stage. The wear rate in the last cycle becomes faster obviously, indicating that it has entered the severe wear stage. Between the 17mm-33mm and 33-47mm cycles, the wear rates are low and similar. The wear rate in the 33-47mm cycle is even lower than that in the 17mm-33mm cycle. Therefore, it is inferred that it has not entered the severe wear stage before 47mm. In the 41-57mm wear cycle, the wear rate increases significantly, indicating that the dividing point for entering the severe wear stage should be between 41-5 7, and 50mm is taken as the dividing point for entering the severe wear stage; by constructing a statistical model, the data such as equipment operating time, stone coal discharge times and grinding roller lifting times are systematically analyzed, and combined with the relationship between unit consumption, loading pressure, primary air pressure and coal feed rate, an optimization adjustment model is established, which can clean historical data and fit the normal range interval, so that the parameters such as unit consumption, loading pressure, primary air pressure of the coal mill can operate within the normal range. When the parameters deviate from the normal range, the system will promptly notify the operating personnel to make adjustments to ensure that the coal mill operates in the best state, reduce energy consumption and improve operating efficiency.

[0053] S3: Monitor the operating status of the coal mill in real time, evaluate the degradation of the coal mill and the wear of the grinding rollers, provide adjustment suggestions and assist in formulating maintenance strategies.

[0054] Furthermore, the evaluation of coal mill degradation and roller wear includes real-time monitoring of whether the current coal mill coal consumption deviates from the normal range based on the online optimization adjustment model of coal mill unit consumption. When it deviates from the normal range, the adjustment direction of the relevant adjustable performance parameters is given and the parameter changes in the adjustment process are tracked visually in real time to assist in the control of the adjustment process; when the coal mill unit consumption degradation state is in the severe wear stage and the wear amount is greater than or equal to 60mm, the monitoring system will issue a high-risk warning and notify the operating personnel to immediately conduct on-site inspection of the coal mill and troubleshoot equipment faults.

[0055] It should be noted that by real-time monitoring of key parameters such as coal mill unit consumption, loading pressure, primary air pressure, and using degradation assessment models and wear measurement models, the degradation state of the coal mill and the wear of the grinding rollers can be accurately assessed. When the system detects that the unit consumption degradation state of the coal mill has reached the severe wear stage and the wear amount is greater than or equal to 60 mm, a high-risk warning is immediately issued to notify the operating personnel to conduct on-site inspections and troubleshooting. This not only improves the reliability and safety of the coal mill operation, but also extends the equipment service life and reduces maintenance costs through timely adjustments and maintenance.

[0056] Example 2

[0057] An embodiment of the present invention provides a method for evaluating the state of a medium-speed coal mill based on the coal grinding unit consumption characteristics. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0058] The coal mill of unit A in the power plant has only been running for 826 hours after overhaul. The system prompts that the unit consumption of the coal mill is abnormally high and exceeds the normal range. The coal mill operation status data, including coal mill current, voltage, pebble coal discharge door status, hydraulic loading force, roller lifting status, etc., are collected and analyzed. The unit consumption of the coal mill is calculated, and the unit consumption data is compared with the coal feed of the coal mill. A scatter plot of unit consumption-coal feed is drawn. The actual unit consumption data is compared with the normal range predicted by the system model to determine whether the unit consumption deviates from the normal range. After the system prompts abnormal wear, the situation is verified with the power plant specialist and it is found that the gap between the dynamic and static rings was adjusted too small during the overhaul process, resulting in the inability to discharge the pebble coal normally. According to the system prompt, the operator adjusts the gap between the dynamic and static rings to ensure that the pebble coal can be discharged normally. The unit consumption and operation status of the coal mill are continuously monitored to ensure that the adjusted operating parameters return to the normal range. With reference to Table 1, the coal mill data are recorded and analyzed.

[0059] Table 1 Coal mill data record table

[0060]

[0061] It can be seen from the table that the actual unit consumption of the coal mill of unit A exceeds the normal range predicted by the model at different coal feed rates, and the actual unit consumption in each operating period is higher than the upper limit of the unit consumption predicted by the model. The system prompts an abnormality, which indicates that there is a problem with the operating status of the coal mill after maintenance. Combined with the verification with the power plant specialist, it was found that the gap between the dynamic and static rings was adjusted too small, resulting in the inability to discharge the stone coal normally. The coal mill could only grind the stones hard, which increased energy consumption. By comparing the system monitoring with the actual data, the cause of the abnormal operation of the coal mill was successfully discovered, that is, the gap between the dynamic and static rings was adjusted too small. After the system prompted abnormal wear, the stone coal was able to be discharged normally by adjusting the gap between the dynamic and static rings, and the unit consumption of the coal mill was restored to the normal range. Therefore, our invention is helpful to timely discover and solve problems in the operation of the coal mill, and improve the operating efficiency and economy of the coal mill.

[0062] Example 3

[0063] Reference Figure 2 , which is an embodiment of the present invention, provides a medium-speed coal mill state assessment system based on coal grinding unit consumption characteristics, including a trend analysis module, a model building module, and a state assessment module.

[0064] The trend analysis module is used to collect coal mill related data and analyze the change trend of coal mill indicators; the model building module is used to build statistical models and optimization adjustment models, determine the normal range of unit consumption, loading pressure and primary air pressure, and build a coal mill unit consumption degradation assessment model and a roller wear calculation model; the status assessment module is used to monitor the operating status of the coal mill in real time, evaluate the degradation of the coal mill and the wear of the roller, provide adjustment suggestions and assist in formulating maintenance strategies.

[0065] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0066] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0067] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering, or processing in another suitable manner as necessary, and then stored in a computer memory.

[0068] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc. It should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not limited. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

[0069] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for evaluating the state of a medium-speed coal mill based on coal grinding unit consumption characteristics, characterized in that: include: Collect relevant data of coal mill and analyze the index change trend of coal mill; Build statistical models and optimization adjustment models, determine the normal range of unit consumption, loading pressure, and primary air pressure, and build a coal mill unit consumption degradation assessment model and a roller wear calculation model; Monitor the coal mill operating status in real time, evaluate coal mill degradation and roller wear, provide adjustment suggestions and assist in formulating maintenance strategies; Coal mill related data include coal mill motor current, voltage, stone coal discharge door status, hydraulic loading force, roller lifting status, coal mill maintenance records, roller measurement and replacement data; The coal mill unit consumption degradation assessment model includes comparing the distribution data of coal mill unit consumption under different coal amounts in different months based on the coal mill unit consumption data, drawing the distribution curve of unit consumption-coal feeding amount, and constructing the coal mill unit consumption degradation assessment model under different states by analyzing the unit consumption characteristics of the coal mill under different operation stages. The coal feeding amount in the model is x, x∈[30,60], the unit consumption in the model is y, and the unit consumption degradation states include normal stage, slight wear stage, abnormal wear stage and severe wear stage; The unit consumption degradation assessment model of coal mill in the normal stage is expressed as: 0.0016x 2 -0.2555x+16.414<y≤0.0021x 2 -0.3124x+18.171 The unit consumption degradation evaluation model of coal mill under the slight wear stage is expressed as: 0.0021x 2 -0.3124x+18.171<y≤0.0025x 2 -0.3634x+19.771 The unit consumption degradation evaluation model of coal mill under abnormal wear stage is expressed as: 0.0025x 2 -0.3634x+19.771<y≤0.003x 2 -0.4185x+21.41 The unit consumption degradation evaluation model of coal mill under severe wear stage is expressed as: y>0.003x 2 -0.4185x+21.41 Based on the coal mill unit consumption degradation evaluation model under different conditions, the unit consumption degradation evaluation is carried out, and the coal feed rate and unit consumption are substituted respectively to obtain the unit consumption point P(x n ,y n ), judge the state of each single consumption point, take the single consumption point in the most deteriorated state as the current single consumption deterioration state of the coal mill, and when the most deteriorated states are greater than or equal to two, take the most serious state as the output result; The roller wear calculation model includes the evaluation of the roller wear state and the calculation of the wear rate. The wear rate μ at different stages = wear rate factor × average wear rate of coal mill. Average wear rate of coal mill = roller wear amount within the statistical time / accumulated running time. The wear rate is divided into three stages, including the initial running-in stage, stable wear stage, and severe wear stage. When the wear amount is greater than 0 mm and less than 15 mm, the wear rate is in the initial running-in stage, and the wear rate factor is 1.53; When the wear amount is greater than or equal to 15 mm and less than 50 mm, the wear rate is in the stable wear stage, and the wear rate factor is 0.72; When the wear amount is greater than or equal to 50 mm, the wear rate is in the severe wear stage, and the wear rate factor is 1.66; The coal mill running time, roller wear, wear rate and average wear rate are counted and analyzed. The wear rate factor of each measurement cycle = wear rate in the measurement cycle / average wear rate; The real-time wear rate of the coal mill roller is corrected based on the real-time unit consumption of the coal mill. When the ratio of the real-time unit consumption of the coal mill to the predicted unit consumption is greater than 1, the current wear rate is adjusted to the wear rate of the current corresponding wear stage × the ratio of the real-time unit consumption of the coal mill to the expected unit consumption.

2. The method for evaluating the state of a medium-speed coal mill based on coal grinding unit consumption characteristics according to claim 1, characterized in that: The index change trend analysis includes calculating the unit consumption of coal mill, which is expressed as: Among them, E c is the coal mill coal grinding unit consumption, I is the coal mill current, V is the coal mill voltage, P F is the power factor, F is the coal feeding amount. Based on historical data, the relationship between the unit consumption of coal mill and the coal feeding amount is analyzed through a scatter plot. The unit consumption of coal mill is negatively correlated with the coal feeding amount. When different coal mills grind different coal qualities, there are differences in the upper and lower ranges of unit consumption under the same coal amount. Through time series distribution analysis, the changing trend of unit consumption with running time is shown, and the running time is positively correlated with the unit consumption of coal mill.

3. The method for evaluating the state of a medium-speed coal mill based on the coal grinding unit consumption characteristics according to claim 2, characterized in that: The construction of the statistical model and the optimization adjustment model includes counting the equipment operation time, the number of stone coal discharges and the number of roller lifting and lowering times through a counter, measuring the roller wear through the operation time, and correcting the coal mill state assessment, assisting in the judgment of coal quality changes through the number of stone coal discharges, and assessing the roller wear through the number of roller lifting and lowering times; The historical data of unit consumption, loading pressure, primary air pressure and coal feeding amount are extracted for analysis to construct an optimization adjustment model. The data during the period of discrete data addition and subtraction of load in the historical data are cleaned, and the fitting slope of the data in the most recent ten seconds is taken as the rate of change of the coal feeding amount. Based on the cleaned data, the upper and lower edge lines are fitted to obtain the upper and lower limits of the normal range of the unit consumption, loading pressure and primary air pressure of the coal mill. By placing the real-time parameters in the corresponding interval band for comparison, it is determined whether the current state is normal. When the parameters of the unit consumption, loading pressure and primary air pressure of the coal mill deviate from the interval band corresponding to the normal state, the operating personnel are notified to perform real-time optimization and adjustment to adjust the unit consumption of the coal mill to within the normal range.

4. The method for evaluating the state of a medium-speed coal mill based on coal grinding unit consumption characteristics according to claim 3, characterized in that: The evaluation of coal mill degradation and roller wear includes real-time monitoring of whether the current coal mill coal consumption deviates from the normal range based on the coal mill unit consumption online optimization adjustment model. When it deviates from the normal range, the adjustment direction of the relevant adjustable performance parameters is given and the parameter changes of the adjustment process are visually tracked in real time to assist in the control of the adjustment process. When the unit consumption degradation state of the coal mill is in the severe wear stage and the wear amount is greater than or equal to 60mm, the monitoring system will issue a high-risk warning and notify the operating personnel to immediately conduct on-site inspection of the coal mill and troubleshoot equipment faults.

5. A system using the medium-speed coal mill state assessment method based on coal grinding unit consumption characteristics as claimed in any one of claims 1 to 4, characterized in that: Including trend analysis module, model building module, and status assessment module; The trend analysis module is used to collect coal mill related data and perform index change trend analysis of the coal mill; The model building module is used to build a statistical model and an optimization adjustment model, determine the normal range of unit consumption, loading pressure, and primary air pressure, and build a coal mill unit consumption degradation assessment model and a roller wear measurement model; The status assessment module is used to monitor the operating status of the coal mill in real time, assess the degradation of the coal mill and the wear of the grinding rollers, provide adjustment suggestions and assist in formulating maintenance strategies.

6. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method for evaluating the state of a medium-speed coal mill based on the coal grinding unit consumption characteristics described in any one of claims 1 to 4 are implemented.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for evaluating the state of a medium-speed coal mill based on the coal grinding unit consumption characteristics described in any one of claims 1 to 4 are implemented.

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