A steam-driven induced draft fan variable operating condition mechanism modeling method, system and storage medium

Abstract

The present invention discloses a variable operating condition mechanism modeling method, system and storage medium of a steam-driven induced draft fan, and the method includes: obtaining a historical database generated by the operation of the steam-driven induced draft fan in a specific time period in the past; taking coal quality and unit load as influencing factors, using the historical database to fit the actual inlet flow change curve; taking the guide vane opening and the actual inlet flow as influencing factors, using the historical database to fit the actual specific pressure energy change curve; taking the guide vane opening and the actual specific pressure energy as influencing factors, using the historical database to fit the actual speed change curve; based on the similarity principle followed when the induced draft fan is running at a variable speed, the actual inlet flow change curve, the actual specific pressure energy change curve and the actual speed change curve are converted and merged to obtain a variable speed operation characteristic curve diagram; extracting and fitting a design specific pressure energy mathematical model and an operation efficiency mathematical model from the variable speed operation characteristic curve diagram. The present invention can improve the reliability of the evaluation of the operation efficiency of the steam-driven induced draft fan.

Description

Technical Field

[0001] The invention relates to the technical field of control of steam-driven induced draft fans in power plants, and in particular to a method, system and storage medium for modeling a variable operating condition mechanism of a steam-driven induced draft fan. Background Art

[0002] In order to reduce the power consumption rate of the plant and save raw coal, and to avoid the problems of large starting current and too low power voltage of the plant generated by the motor drive of the induced draft fan of the million-unit unit, the steam-driven induced draft fan has been put into practical use in large-scale thermal power units in my country. In order to make the steam-driven induced draft fan achieve the best operating efficiency, the technicians collect a large amount of operating data when the steam-driven induced draft fan is running to estimate the configuration relationship of the unit load, speed and guide vane opening when the steam-driven induced draft fan has the best operating efficiency.

[0003] The operating efficiency of a steam-driven induced draft fan is actually closely related to its flue gas flow characteristics, flue pipe characteristics and the performance of the induced draft fan itself. The flue gas flow characteristics and flue pipe characteristics are affected by the coal quality, and the performance of the induced draft fan itself is affected by the unit load. However, many scholars currently only rely on the unit load factor when evaluating the optimal operating efficiency of a steam-driven induced draft fan. At the same time, the evaluation model formula given covers too many unknown parameters and is too idealized, which can easily cause large errors when applied to actual production processes. Summary of the invention

[0004] The present invention provides a method, system and storage medium for modeling a variable operating condition mechanism of a steam-driven induced draft fan to solve one or more technical problems existing in the prior art and at least provide a beneficial choice or create conditions.

[0005] An embodiment of the present invention provides a method for modeling a variable operating condition mechanism of a steam-driven induced draft fan, the method comprising:

[0006] Obtain the historical database generated by the operation of the steam-driven induced draft fan during a specific period of time in the past;

[0007] Taking coal quality and unit load as influencing factors, the actual inlet flow rate variation curve of the induced draft fan is obtained by fitting using the historical database;

[0008] Taking the guide vane opening and the actual inlet flow rate as influencing factors, the actual specific pressure energy variation curve of the induced draft fan is obtained by fitting using the historical database;

[0009] Taking the guide vane opening and the actual specific pressure energy as influencing factors, the actual speed change curve of the induced draft fan is obtained by fitting using the historical database;

[0010] Based on the similar principle followed by the induced draft fan during variable speed operation, the actual inlet flow rate change curve, the actual specific pressure energy change curve and the actual speed change curve are converted and merged to obtain a variable speed operation characteristic curve diagram of the induced draft fan;

[0011] The design specific pressure energy mathematical model and the operation efficiency mathematical model of the induced draft fan are extracted and fitted from the variable speed operation characteristic curve diagram.

[0012] Furthermore, the acquisition of the historical database generated by the operation of the steam-driven induced draft fan in the past specific time period includes:

[0013] Calling the initial historical database generated by the operation of the steam-driven induced draft fan during a specific period of time in the past;

[0014] According to the predetermined normal value ranges of various indicators of the steam-driven induced draft fan during operation, unqualified sample data contained in the initial historical database is eliminated to obtain an updated historical database.

[0015] Furthermore, the actual inlet flow rate variation curve of the induced draft fan is:

[0016] Q=0.00027894L 2 -0.00013363C 2 +0.00021404LC-0.65031L+0.94638C+1335.6

[0017] Among them, Q is the actual inlet flow, L is the unit load, and C is the coal quality.

[0018] Furthermore, the actual specific pressure energy variation curve of the induced draft fan is:

[0019] P=1.1664β 2 +0.029919Q 2 -0.261βQ+51.704β-17.82Q+4280.1

[0020] Among them, P is the actual specific pressure energy, β is the guide vane opening, and Q is the actual inlet flow rate.

[0021] Furthermore, the actual speed variation curve of the induced draft fan is:

[0022] n=α(0.7331β 2 +0.000013658P 2 -0.0123βP-58.853β+1.0013P+4316.1)

[0023] Among them, n is the actual speed, α is the load segmentation coefficient, P is the actual specific pressure energy, and β is the guide vane opening.

[0024] Furthermore, the similarity principle followed by the induced draft fan during variable speed operation satisfies the following formula:

[0025]

[0026] Among them, Q is the actual inlet flow, Q 0 is the designed inlet flow rate, n is the actual speed, n 0 is the design speed, P is the actual specific pressure energy, P 0 is the design specific pressure energy.

[0027] Furthermore, the design specific pressure energy mathematical model of the induced draft fan is:

[0028]

[0029] Among them, P 0 is the design specific pressure energy, Q 0 is the design inlet flow rate, and β is the guide vane opening.

[0030] Furthermore, the mathematical model of the operating efficiency of the induced draft fan is:

[0031]

[0032] Among them, η is the operating efficiency, Q 0 is the design inlet flow rate, P 0 is the design specific pressure energy.

[0033] In addition, an embodiment of the present invention further provides a variable operating condition mechanism modeling system for a steam-driven induced draft fan, the system comprising:

[0034] An acquisition module is used to acquire a historical database generated by the operation of the steam-driven induced draft fan in a specific time period in the past;

[0035] The first fitting module is used to use the coal quality and unit load as influencing factors and to obtain the actual inlet flow rate variation curve of the induced draft fan by fitting using the historical database;

[0036] The second fitting module is used to use the guide vane opening and the actual inlet flow rate as influencing factors and to obtain the actual specific pressure energy change curve of the induced draft fan by fitting using the historical database;

[0037] A third fitting module is used to use the guide vane opening and the actual specific pressure energy as influencing factors and to obtain the actual speed change curve of the induced draft fan by fitting using the historical database;

[0038] A fusion module is used to convert and fuse the actual inlet flow change curve, the actual specific pressure energy change curve and the actual speed change curve based on the similarity principle followed by the induced draft fan during variable speed operation, so as to obtain a variable speed operation characteristic curve diagram of the induced draft fan;

[0039] The extraction module is used to extract and fit the design specific pressure energy mathematical model and the operation efficiency mathematical model of the induced draft fan from the variable speed operation characteristic curve diagram.

[0040] In addition, an embodiment of the present invention further provides a computer-readable storage medium on which an application is stored. When the application is executed by a processor, the above-mentioned method for modeling the variable operating condition mechanism of the steam-driven induced draft fan is implemented.

[0041] The present invention has at least the following beneficial effects: by introducing the two main factors of coal quality and unit load, the historical database generated by the operation of the steam-driven induced draft fan is used to perform fitting calculations on relevant curves, and then the similarity principle followed by the induced draft fan during variable speed operation is used to convert the final operating efficiency evaluation model, and the model covers fewer unknown parameters, thereby improving the reliability of the evaluation of the operating efficiency of the steam-driven induced draft fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0043] Figure 1 It is a flow chart of a method for modeling a variable operating condition mechanism of a steam-driven induced draft fan in an embodiment of the present invention;

[0044] Figure 2 is a variable speed operation characteristic curve diagram of the induced draft fan in the embodiment of the present invention;

[0045] Figure 3 It is a schematic diagram of the structural composition of a variable operating condition mechanism modeling system of a steam-driven induced draft fan in an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0047] It should be noted that, although the functional modules are divided in the system schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the system or the order in the flowchart. The terms "first", "second", etc. in the specification, claims and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0048] Please refer to Figure 1 , Figure 1 1 is a flow chart of a method for modeling a variable operating condition mechanism of a steam-driven induced draft fan provided by an embodiment of the present invention, the method comprising the following steps:

[0049] S101. Acquire a historical database generated by the operation of the steam-driven induced draft fan in a specific time period in the past.

[0050] During the implementation process, the initial historical database generated by the operation of the steam-driven induced draft fan in the past specific time period is first called; secondly, according to the pre-defined normal value range of various indicators of the steam-driven induced draft fan during operation, the unqualified sample data contained in the initial historical database are eliminated, and then an updated historical database is obtained, in which various indicators include coal quality, unit load, actual inlet flow, guide vane opening, actual specific pressure energy and actual speed.

[0051] Specifically, the process of eliminating unqualified sample data includes: first, time-correlated all sample data contained in the initial historical database; secondly, obtaining the values ​​of each indicator at time t (t≥1), and when it is determined that at least one indicator value does not fall within its corresponding normal value range, all indicator values ​​at time t are eliminated; on the contrary, when it is determined that each indicator value falls within its corresponding normal value range, all indicator values ​​at time t are retained; then, each indicator value at time t+1 is obtained and judged in the same way, and so on, until the data cleaning work of the initial historical database is completed.

[0052] S102, taking coal quality and unit load as influencing factors, and using the historical database to fit the actual inlet flow rate variation curve of the induced draft fan.

[0053] Specifically, since the flue gas flow characteristics and the flue pipe characteristics are related to the coal quality used in the power plant, and the performance of the induced draft fan itself is related to the unit load of the steam-driven induced draft fan, the embodiment of the present invention aims to reduce the estimation deviation of the operating efficiency of the steam-driven induced draft fan, comprehensively considers the flue gas flow characteristics, the flue pipe characteristics and the performance of the induced draft fan itself, takes the coal quality and the unit load as independent variables, and uses the historical database to construct the actual inlet flow change curve of the induced draft fan.

[0054] During the implementation process, several sets of first data sets at different times are obtained from the historical database, wherein the first data sets include coal quality, unit load and actual inlet flow rate, and then the actual inlet flow rate change curve of the induced draft fan is fitted as follows:

[0055] Q=0.00027894L 2 -0.00013363C 2 +0.00021404LC-0.65031L+0.94638C+1335.6

[0056] Where: Q is the actual inlet flow, L is the unit load, and C is the coal quality.

[0057] S103, taking the guide vane opening and the actual inlet flow rate as influencing factors, and using the historical database to fit the actual specific pressure energy change curve of the induced draft fan.

[0058] During the implementation process, several sets of second data sets at different times are obtained from the historical database, wherein the second data sets include the guide vane opening, the actual inlet flow rate and the actual specific pressure energy, and then the actual specific pressure energy change curve of the induced draft fan is fitted as follows:

[0059] P=1.1664β 2 +0.029919Q 2 -0.261βQ+51.704β-17.82Q+4280.1

[0060] Where: P is the actual specific pressure energy, β is the guide vane opening, and Q is the actual inlet flow rate.

[0061] It should be noted that, since the guide vane opening range of the steam-driven induced draft fan is 0-100%, the several groups of second data sets selected in the embodiment of the present invention at least cover each guide vane opening within the guide vane opening range and its associated actual inlet flow and actual specific pressure energy.

[0062] S104, taking the guide vane opening and the actual specific pressure energy as influencing factors, and using the historical database to fit the actual speed change curve of the induced draft fan.

[0063] During the implementation process, several sets of third data sets at different times are obtained from the historical database, wherein the third data set includes the guide vane opening, the actual specific pressure energy and the actual speed, and then the actual speed change curve of the induced draft fan is fitted as follows:

[0064] n=α(0.7331β 2 +0.000013658P 2 -0.0123βP-58.853β+1.0013P+4316.1)

[0065] Where: n is the actual rotational speed, α is the load segmentation coefficient, P is the actual specific pressure energy, and β is the guide vane opening degree.

[0066] It should be noted that the provisions for the value of the load segmentation coefficient α in the embodiments of the present invention are as follows: when the unit load generated by the steam-driven induced draft fan falls within the range of L ≤ 450 MW, the value of α is 1; when the unit load generated by the steam-driven induced draft fan falls within the range of 450 MW < L ≤ 900 MW, the value of α is 1.3167; when the unit load generated by the steam-driven induced draft fan falls within the range of L > 900 MW, the value of α is 1.5208.

[0067] S105. Based on the similarity principle followed during the variable-speed operation of the induced draft fan, convert and fuse the actual inlet flow rate change curve, the actual specific pressure energy change curve, and the actual rotational speed change curve to obtain the variable-speed operation characteristic curve graph of the induced draft fan.

[0068] In the embodiments of the present invention, the similarity principle followed during the variable-speed operation of the induced draft fan satisfies the following formula:

[0069]

[0070] Where, Q is the actual inlet flow rate, Q 0 is the designed inlet flow rate, n is the actual rotational speed, n 0 is the designed rotational speed, P is the actual specific pressure energy, P 0 is the designed specific pressure energy.

[0071] During the implementation process, according to the above similarity principle, it can be known that during the variable-speed operation of the induced draft fan, only the numerical changes of the rotational speed, inlet flow rate, and specific pressure energy will be affected, but it is stipulated that the constant opening degree line and constant efficiency line before and after the variable speed of the induced draft fan remain unchanged. In the embodiments of the present invention, the actual rotational speed obtained by solving the actual rotational speed change curve under the current working condition of the steam-driven induced draft fan is used. According to the ratio between the actual rotational speed and the proposed designed rotational speed, the actual inlet flow rate change curve is converted to obtain the initial inlet flow rate change curve, and the actual specific pressure energy change curve is converted to obtain the initial specific pressure energy change curve. At this time, based on the self-variable cross relationship between the initial inlet flow rate change curve and the initial specific pressure energy change curve, the above two change curves are fused into the same coordinate system, and then the functional relationship between the inlet flow rate (m 3 / s), specific pressure energy (Nm / kg), operating efficiency (%), and guide vane opening degree (°) is constructed, that is, the variable-speed operation characteristic curve graph of the induced draft fan is converted, as Figure 2 shown.

[0072] S106. Extract and fit the designed specific pressure energy mathematical model and the operating efficiency mathematical model of the induced draft fan from the variable-speed operation characteristic curve graph.

[0073] During the implementation process, since the specific pressure energy is related to the guide vane opening and the inlet flow rate, several data points are extracted from the variable speed operation characteristic curve, and each data point corresponds to the guide vane opening, the inlet flow rate and the specific pressure energy, and then the design specific pressure energy mathematical model of the induced draft fan is fitted as follows:

[0074]

[0075] Among them, P 0 is the design specific pressure energy, Q 0 is the design inlet flow rate, and β is the guide vane opening.

[0076] During the implementation process, since the operating efficiency is related to the inlet flow rate and specific pressure energy, several data points are extracted from the variable speed operation characteristic curve, and each data point corresponds to the inlet flow rate, specific pressure energy and operating efficiency, and then the operating efficiency mathematical model of the induced draft fan is fitted as follows:

[0077]

[0078] Among them, η is the operating efficiency, Q 0 is the design inlet flow rate, P 0 is the design specific pressure energy.

[0079] In the embodiment of the present invention, by introducing the two main factors of coal quality and unit load, the historical database generated by the operation of the steam-driven induced draft fan is used to perform fitting calculations on the relevant curves, and then the similarity principle followed by the induced draft fan during variable speed operation is used to convert the final operating efficiency evaluation model, and the model covers fewer unknown parameters, thereby improving the reliability of the evaluation of the operating efficiency of the steam-driven induced draft fan.

[0080] Please refer to Figure 3 , Figure 3 1 is a schematic diagram of the structure of a variable operating condition mechanism modeling system for a steam-driven induced draft fan provided by an embodiment of the present invention, wherein the system comprises the following:

[0081] An acquisition module 201 is used to acquire a historical database generated by the operation of the steam-driven induced draft fan in a specific time period in the past;

[0082] The first fitting module 202 is used to use the coal quality and unit load as influencing factors and use the historical database to fit the actual inlet flow rate change curve of the induced draft fan;

[0083] The second fitting module 203 is used to use the guide vane opening and the actual inlet flow rate as influencing factors and to obtain the actual specific pressure energy variation curve of the induced draft fan by fitting using the historical database;

[0084] The third fitting module 204 is used to use the guide vane opening and the actual specific pressure energy as influencing factors and to obtain the actual speed change curve of the induced draft fan by fitting using the historical database;

[0085] A fusion module 205 is used to convert and fuse the actual inlet flow change curve, the actual specific pressure energy change curve and the actual speed change curve based on the similarity principle followed by the induced draft fan during variable speed operation to obtain a variable speed operation characteristic curve diagram of the induced draft fan;

[0086] The extraction module 206 is used to extract and fit the design specific pressure energy mathematical model and the operation efficiency mathematical model of the induced draft fan from the variable speed operation characteristic curve diagram.

[0087] Regarding the specific limitations on the various component modules in a variable operating condition mechanism modeling system for a steam-driven induced draft fan, reference may be made to the limitations on a variable operating condition mechanism modeling method for a steam-driven induced draft fan in the above embodiment, which will not be elaborated herein.

[0088] In addition, an embodiment of the present invention further provides a computer-readable storage medium on which an application is stored. When the application is executed by a processor, the above-mentioned method for modeling the variable operating condition mechanism of the steam-driven induced draft fan is implemented.

[0089] Those of ordinary skill in the art will appreciate that all or some of the steps and systems in the disclosed method above can be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components can be implemented as software executed by a central processing unit, a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit. Such software can be distributed on a computer-readable medium, and the computer-readable medium can include a computer storage medium (or a non-transitory medium) and a communication medium (or a temporary medium). As known to those of ordinary skill in the art, computer storage media include volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical disk storage, magnetic cassette, magnetic tape, disk storage or other magnetic storage device, or any other medium that can be used to store desired information and can be accessed by a computer. Furthermore, as is well known to those skilled in the art, communication media typically embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0090] The above specifically describes the preferred implementation of the present invention, but the present invention is not limited to the above implementation mode. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A method for modeling the variable operating condition mechanism of a steam-driven induced draft fan, characterized in that: The method comprises: Obtain the historical database generated by the operation of the steam-driven induced draft fan during a specific period of time in the past; Taking coal quality and unit load as influencing factors, the actual inlet flow rate variation curve of the induced draft fan is obtained by fitting using the historical database; Taking the guide vane opening and the actual inlet flow rate as influencing factors, the actual specific pressure energy variation curve of the induced draft fan is obtained by fitting using the historical database; Taking the guide vane opening and the actual specific pressure energy as influencing factors, the actual speed change curve of the induced draft fan is obtained by fitting using the historical database; Based on the similar principle followed by the induced draft fan during variable speed operation, the actual inlet flow rate change curve, the actual specific pressure energy change curve and the actual speed change curve are converted and merged to obtain a variable speed operation characteristic curve diagram of the induced draft fan; Extract and fit the design specific pressure energy mathematical model and operation efficiency mathematical model of the induced draft fan from the variable speed operation characteristic curve diagram; The design specific pressure energy mathematical model of the induced draft fan is: The mathematical model of the operating efficiency of the induced draft fan is: In the formula, is the design specific pressure energy, is the design inlet flow rate, is the guide vane opening, For operational efficiency.

2. The variable operating condition mechanism modeling method of a steam-driven induced draft fan according to claim 1 is characterized in that: The acquisition of the historical database generated by the operation of the steam-driven induced draft fan in the past specific time period includes: Calling the initial historical database generated by the operation of the steam-driven induced draft fan during a specific period of time in the past; According to the predetermined normal value ranges of various indicators of the steam-driven induced draft fan during operation, unqualified sample data contained in the initial historical database is eliminated to obtain an updated historical database.

3. The variable operating condition mechanism modeling method of a steam-driven induced draft fan according to claim 1 is characterized in that: The actual inlet flow rate variation curve of the induced draft fan is: in, is the actual inlet flow, is the unit load, It is coal quality.

4. The variable operating condition mechanism modeling method of a steam-driven induced draft fan according to claim 1 is characterized in that: The actual specific pressure energy variation curve of the induced draft fan is: in, is the actual specific pressure energy, is the actual inlet flow.

5. The variable operating condition mechanism modeling method of a steam-driven induced draft fan according to claim 1 is characterized in that: The actual speed variation curve of the induced draft fan is: in, is the actual speed, is the load segmentation factor, is the actual specific pressure energy.

6. The variable operating condition mechanism modeling method of a steam-driven induced draft fan according to claim 1 is characterized in that: The similarity principle followed by the induced draft fan during variable speed operation satisfies the following formula: in, is the actual inlet flow, is the actual speed, is the design speed, is the actual specific pressure energy.

7. A variable operating condition mechanism modeling system for a steam-driven induced draft fan, characterized in that: The system comprises: An acquisition module is used to acquire a historical database generated by the operation of the steam-driven induced draft fan in a specific time period in the past; The first fitting module is used to use the coal quality and unit load as influencing factors and to obtain the actual inlet flow rate variation curve of the induced draft fan by fitting using the historical database; The second fitting module is used to use the guide vane opening and the actual inlet flow rate as influencing factors and to obtain the actual specific pressure energy change curve of the induced draft fan by fitting using the historical database; A third fitting module is used to use the guide vane opening and the actual specific pressure energy as influencing factors and to obtain the actual speed change curve of the induced draft fan by fitting using the historical database; A fusion module is used to convert and fuse the actual inlet flow change curve, the actual specific pressure energy change curve and the actual speed change curve based on the similarity principle followed by the induced draft fan during variable speed operation, so as to obtain a variable speed operation characteristic curve diagram of the induced draft fan; An extraction module, used for extracting and fitting a design specific pressure energy mathematical model and an operation efficiency mathematical model of the induced draft fan from the variable speed operation characteristic curve diagram; The design specific pressure energy mathematical model of the induced draft fan is: The mathematical model of the operating efficiency of the induced draft fan is: In the formula, is the design specific pressure energy, is the design inlet flow rate, is the guide vane opening, For operational efficiency.

8. A computer-readable storage medium having an application program stored thereon, characterized in that: When the application is executed by the processor, the method for modeling the variable operating condition mechanism of the steam-driven induced draft fan as described in any one of claims 1 to 6 is implemented.

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