Method and device for estimating calorific value of coal fed into a furnace

Abstract

The application provides a method and device for estimating the calorific value of coal entering a furnace, and relates to the field of pulverized coal boiler combustion. The method comprises the following steps: determining the current load of a target once-through boiler and pre-configured relationship data of the target once-through boiler; performing load matching based on the current load and the pre-configured relationship data to obtain a current load coefficient corresponding to the current load; obtaining the real-time feed water flow and the real-time amount of coal entering the furnace of the target once-through boiler; and estimating the real-time calorific value of coal entering the furnace of the target once-through boiler according to the current load coefficient, the real-time feed water flow and the real-time amount of coal entering the furnace. Compared with the way of obtaining the calorific value of coal entering the furnace through physical sampling and laboratory analysis in the related art, the method realizes continuous online monitoring of the calorific value of coal entering the furnace, and improves the real-time performance and accuracy of the monitoring of the calorific value of coal entering the furnace.

Description

Technical Field

[0001] This application relates to the field of coal combustion technical analysis, and in particular to a method and apparatus for estimating the calorific value of coal fed into the furnace. Background Technology

[0002] The calorific value of coal fed into the furnace is a key indicator for coal-fired power plants. The relevant technology obtains the calorific value of coal fed into the furnace by using an automatic sampler to periodically sample coal at the coal conveyor belt or feeder. The collected coal samples are then crushed, reduced in size, and sent to a laboratory for analysis to obtain the calorific value of the coal fed into the furnace.

[0003] Due to the complexity and high cost of laboratory analysis, continuous testing of coal samples is not possible. The sampling and testing frequency of coal is usually 1-2 times per day. The sampling of coal entering the furnace is usually carried out some time after the coal has entered the furnace. Therefore, the sampling results reflect the coal quality over a period of time and cannot reflect the calorific value of the coal entering the furnace in real time. Summary of the Invention

[0004] This application aims to at least partially address one of the technical problems in the related art. To this end, this application proposes a method and apparatus for estimating the calorific value of coal fed into the furnace, which can realize continuous online monitoring of the calorific value of coal fed into the furnace, thereby improving the accuracy and real-time performance of coal calorific value detection.

[0005] This application proposes a method for estimating the calorific value of coal fed into a boiler. The method includes: determining the current load of a target once-through boiler and pre-configured relationship data of the target once-through boiler; wherein, the pre-configured relationship data is used to describe the correspondence between boiler load and load factor; the load factor is used to characterize the characteristics of the current load of the target once-through boiler; performing load matching based on the current load and the pre-configured relationship data to obtain the current load factor corresponding to the current load; obtaining the real-time feedwater flow rate and real-time coal feed rate of the target once-through boiler; and estimating the real-time calorific value of coal fed into the target once-through boiler based on the current load factor, real-time feedwater flow rate, and real-time coal feed rate.

[0006] In one embodiment, load matching is performed based on the current load and pre-configured relationship data to obtain the current load coefficient corresponding to the current load, including: determining the target load segment to which the current load belongs; and using the target load segment to search in the pre-configured relationship data to obtain the current load coefficient.

[0007] In one embodiment, the target DC boiler includes a coal feeder and an economizer; the real-time water flow rate and real-time coal feed rate of the target DC boiler are obtained; the real-time water flow rate is collected through a water flow rate measuring point set at the economizer inlet; and the real-time coal feed rate is collected through a coal feed rate measuring point set inside the coal feeder.

[0008] In one embodiment, the real-time calorific value of the target once-through boiler is estimated based on the current load factor, real-time feedwater flow rate, and real-time coal feed rate, including: determining the real-time boiler water-coal ratio based on the ratio between the real-time feedwater flow rate and the real-time coal feed rate; and estimating the real-time calorific value of the target once-through boiler based on the current load factor and the real-time boiler water-coal ratio.

[0009] In one embodiment, the real-time calorific value of the target once-through boiler's feed coal is estimated based on the current load factor and the real-time boiler water-to-coal ratio, including: determining the real-time calorific value of the target once-through boiler's feed coal by the following method:

[0010] q 煤 =f p ·(M 水 / M 煤 )

[0011] Where, q 煤 M represents the real-time calorific value of the coal fed into the furnace. 水 For real-time water supply flow rate; M 煤 This refers to the real-time coal feed rate; f p This represents the current load factor.

[0012] In one embodiment, the load factor is related to the enthalpy increase per unit mass of feedwater in the water-cooled wall, the proportion of coal burned out in the furnace, and the proportion of heat absorbed by the water-cooled wall to the total heat absorbed by the boiler.

[0013] In one embodiment, pre-configured relationship data is determined by: dividing the target DC boiler load into different load segments, wherein the different load segments are boiler maximum load values ​​taken at fixed intervals; when the target DC boiler is operating at a preset load within any load segment, obtaining the real-time feedwater flow rate, real-time coal feed rate, and tested coal calorific value of the target DC boiler, and calculating the load factor corresponding to any load segment; and establishing pre-configured relationship data based on the load factor corresponding to each load segment.

[0014] In one embodiment, pre-configured relationship data is established based on the load factor corresponding to each load segment, including: using the historical load, historical feedwater flow, historical coal input and calorific value of the target DC boiler's coal-fired unit to correct the load factor corresponding to each load segment, thereby obtaining the corrected load factor corresponding to each load segment; and pre-configured relationship data is established based on the corrected load factor corresponding to each load segment.

[0015] In one embodiment, the calorific value of the coal fed into the furnace is obtained by sampling, crushing, reducing and analyzing the real-time coal feed amount.

[0016] This application also provides a device for estimating the calorific value of coal fed into the boiler. The device includes: a relational data determination module, used to determine the current load of the target once-through boiler and the pre-configured relational data of the target once-through boiler; wherein, the pre-configured relational data is used to describe the correspondence between boiler load and load factor; the load factor is used to characterize the characteristics of the current load of the target once-through boiler when the current load is determined; a load factor matching module, used to perform load matching based on the current load and the pre-configured relational data to obtain the current load factor corresponding to the current load; a water and coal quantity acquisition module, used to acquire the real-time feedwater flow rate and real-time coal quantity of the target once-through boiler; and a coal calorific value estimation module, used to estimate the real-time calorific value of coal fed into the target once-through boiler based on the current load factor, real-time feedwater flow rate, and real-time coal quantity.

[0017] This application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of any of the methods described above.

[0018] This application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the methods described above.

[0019] In the above embodiments, since pre-configured relational data describing the correspondence between boiler load and load factor is pre-established, after determining the current load of the target once-through boiler, load matching can be performed based on the current load and the pre-configured relational data to obtain the current load factor corresponding to the current load; furthermore, the real-time feedwater flow rate and real-time coal feed rate of the target once-through boiler are obtained; thus, the real-time calorific value of the coal feed rate of the target once-through boiler can be estimated based on the current load factor, real-time feedwater flow rate, and real-time coal feed rate. Compared with the method of obtaining the calorific value of the coal feed rate through physical sampling and laboratory analysis in related technologies, this method realizes continuous online monitoring of the calorific value of the coal feed rate, improving the real-time performance and accuracy of the monitoring. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary examples and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0021] Figure 1a This is a flow chart of feedwater and coal feeding for a once-through boiler according to an embodiment of the method for estimating the calorific value of coal fed into the furnace according to this application.

[0022] Figure 1b This is a flowchart illustrating a method for estimating the calorific value of coal fed into the furnace according to an embodiment of this application;

[0023] Figure 2 This is a schematic diagram of the pre-configured relational data flow for determining the calorific value of coal fed into the furnace according to an embodiment of this application;

[0024] Figure 3 This is a flowchart illustrating a method for estimating the calorific value of coal fed into the furnace according to another embodiment of this application;

[0025] Figure 4 This is a structural block diagram of a coal calorific value estimation device according to an embodiment of this application;

[0026] Figure 5 This is an internal structural diagram of a computer device according to one embodiment of the present application. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, this application will be further described in detail with reference to the following specific embodiments and accompanying drawings. Except for the content specifically mentioned below, the processes, conditions, and experimental methods for implementing this application are all common knowledge and general knowledge in the field, and this application does not have any particular limitations.

[0028] This application provides a method for estimating the calorific value of coal fed into the boiler, applicable to once-through boilers. A once-through boiler refers to a boiler where feedwater, propelled by feedwater pump pressure, sequentially passes through the economizer, water-cooled walls, and superheater, transforming into superheated steam. This is the main structural type of modern large-scale coal-fired boilers. Under normal operating conditions, the feedwater undergoes a transformation process within the water-cooled walls: unsaturated water → saturated water → steam-water mixture → saturated steam → superheated steam. By the time it reaches the steam-water separator, the feedwater has been completely transformed into superheated steam with a certain degree of superheat (10-30℃).

[0029] Figure 1a This is a flowchart of the coal and water feeding process for a once-through boiler. Raw coal enters the coal mill via the coal feeder, where it is ground into pulverized coal of suitable particle size before entering the boiler for combustion and heat release. Feedwater, pressurized by the feedwater pump, passes sequentially through the high-pressure heater and economizer before entering the boiler's water-cooled wall. In the water-cooled wall, it absorbs the heat released by the combustion of the coal, transforming it into superheated steam. After passing through the steam-water separator, it enters the superheater for further heating, forming high-temperature steam of acceptable quality. A belt scale is installed inside the coal feeder, a feedwater flow meter is installed at the economizer inlet, and a steam temperature meter is installed at the steam-water separator outlet. These measures allow for real-time measurement of the feedwater flow rate, the amount of coal entering the boiler, and the superheat of the steam leaving the boiler. The ratio of the feedwater flow rate to the amount of coal entering the boiler is called the water-coal ratio. The superheat of the steam at the steam-water separator outlet typically remains stable during unit operation.

[0030] The feedwater and coal exchange heat within the boiler through water-cooled walls. The heat absorbed by the feedwater is Q. 吸 The effective heat release Q of coal in the furnace area 放They are essentially equal, and have the following relationship:

[0031] Q 吸 =Q 放 Equation (1)

[0032] Q 吸 =M 水 ·ΔH Equation (2)

[0033] Q 放 =M 煤 ·q 煤 ·η 煤 ·η 壁 Equation (3)

[0034] in,

[0035] M 水 The feedwater flow rate is measured at the economizer inlet, and the unit is kg / s;

[0036] ΔH is the enthalpy increase per unit mass of feedwater in the water-cooled wall, and the unit is kJ / kg;

[0037] M 煤 The amount of coal fed into the furnace is measured at the coal feeder, and the unit is kg / s.

[0038] q 煤 This refers to the calorific value of the coal fed into the furnace, expressed in kJ / kg.

[0039] η 煤 This refers to the percentage of coal completely burned before entering the furnace.

[0040] η 壁 The proportion of heat absorbed by the water-cooled wall to the total heat absorbed by the boiler.

[0041] According to equations (1)-(3), we can obtain:

[0042]

[0043] In equation (4), ΔH is the enthalpy increase per unit mass of feedwater in the water-cooled wall, that is, the heat absorbed by each kilogram of feedwater in the boiler water-cooled wall, which is equal to the difference between the enthalpy of the superheated steam at the outlet of the steam-water separator and the enthalpy of the unsaturated water at the outlet of the economizer.

[0044] During boiler operation, the feedwater temperature at the economizer outlet is typically lower than the saturation temperature of the water at the economizer operating pressure; this difference is called feedwater subcooling. If the feedwater subcooling is too low, the feedwater is prone to vaporization within the economizer or just entering the water-cooled walls during operational fluctuations, affecting the flow rate into each water-cooled wall tube and causing deviations in water flow within different tubes. This can lead to variations in heat absorption by the water-cooled walls and localized overheating. Conversely, if the feedwater subcooling is too high, it increases the temperature difference between the flue gas in the furnace and the feedwater in the tubes, increasing irreversible heat transfer losses and reducing the unit's energy utilization efficiency. Therefore, the economizer outlet feedwater subcooling is typically controlled at around 20°C.

[0045] The outlet steam temperature of a steam-water separator is typically higher than the saturation temperature of water at the separator's operating pressure; this difference is called steam superheat. Insufficient steam superheat can lead to water carryover, causing large steam temperature fluctuations and subsequent metal fatigue damage to the heated surfaces. Excessive steam superheat can cause overheating damage to the tube walls in the water-cooled wall outlet area. Therefore, the steam superheat at the steam-water separator outlet is usually controlled within 10-50℃. Boiler operating parameters are meticulously designed and calculated. Under a specific load, the operating pressures of the feedwater and steam are essentially fixed, and the feedwater subcooling and steam superheat are usually controlled around a certain fixed value. Therefore, for a specific boiler, once the boiler load is determined, ΔH can be basically determined.

[0046] In equation (4), η 煤 The combustion rate of coal entering the boiler is related to the volatile matter content of the coal, the excess air coefficient of the boiler, the operation mode of the pulverizing system, and the fineness of the pulverized coal. Volatile matter is the content of substances (gas or liquid) released from coal after heating it at a certain temperature in the absence of air, minus the moisture content. The remaining residue is called coke residue. Because volatile matter is not inherent in coal but is a product of pyrolysis at a specific temperature, it should more accurately be called volatile matter yield. Volatile matter is not only an indicator to consider in coking and gasification but also an important indicator for power coal, serving as an auxiliary indicator for pricing power coal based on calorific value. For modern large-scale pulverized coal boilers, if there is no drastic change in the quality of the coal entering the boiler, η... 煤 It is usually above 95%, so it can be approximated as a constant.

[0047] In equation (4), η 壁 The heat absorption of the water-cooled walls accounts for the proportion of the total heat absorption of the boiler. Feedwater and steam absorb heat in the boiler's water-cooled walls and tail-end heating surfaces, divided into two parts by the water-cooled wall outlet. The first part is the heat absorption within the water-cooled walls, where feedwater is converted into steam with a superheat of 10-30℃. The second part is the heat absorption of superheated steam in the boiler's tail-end heating surfaces, where the steam is converted into superheated steam according to design parameters (at which point the superheat reaches several hundred℃). At this point, η... 壁= Heat absorption of water-cooled wall / (Heat absorption of superheated steam + Heat absorption of water-cooled wall). This value is an important indicator in boiler design, and is mainly affected by the boiler load in design calculations. As shown in Table 1, η varies for different boilers. 壁 The differences are significant; under high load, η in the same boiler... 壁 η is close to and lower than that under low load. 壁 Value (It should be noted that, in most cases, η under high load in the same boiler) 壁 η is close to and lower than that under low load. 壁 However, there are occasional special cases where this value will not have a corresponding impact, such as boiler A in Table 1 (100% maximum load and 75% maximum load). In actual operation, η 壁 It is also affected by the boiler's excess air coefficient, the proportion of coal burned in the furnace, and the degree of fouling of the water-cooled walls. However, unless extreme situations such as severe combustion imbalance in the furnace or severe slagging of the water-cooled walls occur, these factors have little impact on η. 壁 The impact is limited; therefore, during normal operation, η 壁 It can be considered as being affected only by the boiler load.

[0048] For example, η 壁 The relationship with boiler load is shown in the table below:

[0049] Table 1. Proportion of heat absorption by water-cooled walls in different boiler designs

[0050]

[0051] In summary, in equation (4), for a specific boiler, under the condition that the quality of the coal fed into the boiler and the boiler operation are basically stable (this is the normal operating condition of most boilers, which can be met in reality), the proportion of coal burned out η is... 煤 The enthalpy increase ΔH of the feedwater in the water-cooled wall and the proportion of heat absorbed by the water-cooled wall η can be considered constants. 壁 Primarily influenced by boiler load, the calorific value of the coal fed into the boiler can be functionally related to the boiler's water-to-coal ratio.

[0052] q 煤 =f p ·(M 水 / M 煤 Equation (5)

[0053] Where: q 煤 This refers to the real-time calorific value of the coal fed into the furnace, expressed in kJ / kg; M 水 The feedwater flow rate is measured at the economizer inlet, and the unit is kg / s; M 煤 The amount of coal fed into the furnace is measured at the coal feeder, and the unit is kg / s; f p This is the load factor.

[0054] Based on the above analysis, there is a correlation between the calorific value of the coal fed into the boiler and the boiler water-to-coal ratio. The boiler water-to-coal ratio is data that is monitored in real-time during unit operation and can be obtained in real time. Therefore, this specification provides a method for estimating the calorific value of the coal fed into the boiler. Please refer to [link to relevant documentation]. Figure 1b The method includes:

[0055] S110. Determine the current load of the target DC boiler and the pre-configuration relationship data of the target DC boiler.

[0056] The pre-configured relational data describes the correspondence between boiler load and load factor; the load factor characterizes the current load characteristics of the target DC boiler. For example, the pre-configured relational data can be in the form of a table or a function. Given the current load state of the target DC boiler, the pre-configured relational data can be used to determine the load factor corresponding to the current load state. During the normal operation of the target DC boiler, the computer equipment communicatively connected to the target DC boiler stores the current load state of the target DC boiler. The current load state can be characterized by the current actual load data or by the load segment to which the current actual load data belongs.

[0057] Specifically, pre-configured relationship data can be pre-established for each target DC boiler and stored in a computer device. After determining the current load of the target DC boiler, the pre-configured relationship data corresponding to that target DC boiler is retrieved from the computer device. For example, if the target DC boiler has identification information, its corresponding pre-configured relationship data can be retrieved from the computer device based on the identification information. For instance, the pre-configured relationship data can be retrieved from the computer device based on the target DC boiler's serial number information.

[0058] S120. Based on the current load and pre-configured relationship data, perform load matching to obtain the current load coefficient corresponding to the current load.

[0059] Specifically, since the pre-configured relational data is used to describe the correspondence between boiler load and load factor, the current load can be matched with the boiler load in the pre-configured relational data to determine the matched boiler load. The load factor corresponding to the matched boiler load is the current load factor corresponding to the current load.

[0060] S130: Obtain the real-time feedwater flow rate and real-time coal input of the target DC boiler.

[0061] Specifically, feedwater flow measurement points and coal feed rate measurement points are set at relevant locations on the target once-through boiler. Real-time feedwater flow rate is collected through the feedwater flow measurement points, and real-time coal feed rate is collected through the coal feed rate measurement points. Furthermore, in order to obtain accurate real-time feedwater flow rate and real-time coal feed rate, the feedwater flow measurement points and coal feed rate measurement points can be calibrated in advance.

[0062] S140. Estimate the real-time calorific value of the coal fed into the target once-through boiler based on the current load factor, real-time feedwater flow rate, and real-time coal feed rate.

[0063] Specifically, as analyzed above, the calorific value of the coal fed into the boiler is related to the boiler water-coal ratio. Given the real-time feedwater flow rate, real-time coal feed rate, and current load factor, the real-time boiler water-coal ratio can be determined based on the real-time feedwater flow rate and real-time coal feed rate. Thus, the real-time calorific value of the target once-through boiler coal can be estimated based on the current load factor and the real-time boiler water-coal ratio.

[0064] In the above embodiments, since pre-configured relational data describing the correspondence between boiler load and load factor is pre-established, after determining the current load of the target once-through boiler, load matching can be performed based on the current load and the pre-configured relational data to obtain the current load factor corresponding to the current load. Furthermore, the real-time feedwater flow rate and real-time coal feed rate of the target once-through boiler are obtained; thus, the real-time calorific value of the coal feed rate of the target once-through boiler can be estimated based on the current load factor, real-time feedwater flow rate, and real-time coal feed rate. Compared with the related technologies that obtain the calorific value of the coal feed rate through physical sampling and laboratory analysis, this method achieves continuous online monitoring of the calorific value of the coal feed rate, improving the real-time performance and accuracy of the monitoring. Furthermore, in most power plants using related technologies, the coal blending process involves complex coal structures and variable coal quality, which can affect the calorific value of the coal obtained through coal sampling. Therefore, there are some discrepancies between the calorific value of the coal obtained through coal sampling and the actual calorific value of the coal. In this implementation plan, the real-time boiler water-coal ratio and the current load coefficient that matches the current load of the target once-through boiler are used to estimate the real-time calorific value of the coal, which can reduce the deviation between the estimated and actual calorific value of the coal.

[0065] In some implementations, the load factor is used to characterize the current load characteristics of the target once-through boiler. Specifically, the load factor is related to the enthalpy increase per unit mass of feedwater in the water-cooled wall, the proportion of coal burned in the furnace, and the proportion of heat absorbed by the water-cooled wall to the total heat absorbed by the boiler.

[0066] In some implementations, load matching is performed based on the current load and pre-configured relationship data to obtain the current load coefficient corresponding to the current load, including: determining the target load segment to which the current load belongs; and using the target load segment to search in the pre-configured relationship data to obtain the current load coefficient.

[0067] The pre-configured relational data can be used to describe the correspondence between boiler load segments and load factors. It should be noted that the boiler load segment can be obtained by pre-dividing the boiler load of the target once-through boiler into multiple boiler load segments. For each boiler load segment, its corresponding load factor is determined, thereby establishing the correspondence between the boiler load segment and the load factor, which serves as the pre-configured relational data.

[0068] Specifically, after determining the current load of the target once-through boiler, the boiler load segment in which the current load belongs, i.e., the target load segment, is determined. The target load segment is then searched in pre-configured relational data to obtain the corresponding compliance coefficient, which serves as the current load coefficient for the current load. For example, if the pre-configured relational data is in function form, then the pre-configured relational data is the relational function itself. The value of the current load can be substituted into this relational function to determine the value of the current load coefficient.

[0069] In some implementations, the target once-through boiler includes a coal feeder and an economizer. The real-time feedwater flow rate and real-time coal feed rate of the target once-through boiler are obtained: the real-time feedwater flow rate is collected through a feedwater flow rate measuring point set at the economizer inlet; the real-time coal feed rate is collected through a coal feed rate measuring point set inside the coal feeder.

[0070] Please continue reading for more details. Figure 1a The target once-through boiler may include a feedwater pump, a coal feeder, and an economizer. A feedwater flow measurement point is installed at the economizer inlet, and a coal feed rate measurement point is installed inside the coal feeder. Specifically, the real-time feedwater flow rate is collected through the designated feedwater flow measurement point, and the real-time coal feed rate is collected through the designated coal feed rate measurement point.

[0071] In some implementations, the real-time calorific value of the target once-through boiler coal is estimated based on the current load factor, real-time feedwater flow rate, and real-time coal feed rate. This includes: determining the real-time boiler water-coal ratio based on the ratio between the real-time feedwater flow rate and the real-time coal feed rate; and estimating the real-time calorific value of the coal feed rate based on the current load factor and the real-time boiler water-coal ratio.

[0072] Specifically, the calorific value of the coal fed into the furnace can be determined in the following ways:

[0073] q 煤 =f p ·(M 水 / M 煤 )

[0074] Where, q 煤 M represents the real-time calorific value of the coal fed into the furnace. 水 For real-time water supply flow, M 煤 f is the real-time coal feed rate. p This represents the current load factor.

[0075] In some implementations, please refer to Figure 2 After determining the current load of the target DC boiler, the pre-configuration relationship data of the target DC boiler can be determined based on the current load, including:

[0076] S210. Divide the boiler load of the target DC boiler into different load segments.

[0077] The different load segments can be defined as the range of different intervals into which the target once-through boiler's load falls. For example, the division criteria can be based on a fixed percentage of the boiler's maximum load value at intervals, such as a fixed percentage of 10% of the boiler's maximum load. In this case, the boiler load segments can be divided as follows: 100% load segment (95%-100% maximum load), 90% load segment (85%-95% maximum load), 80% load segment (75%-85% maximum load), 70% load segment (65%-75% maximum load), 60% load segment (55%-65% maximum load), 50% load segment (45%-55% maximum load), 40% load segment (35%-45% maximum load), and 30% load segment (25%-35% maximum load).

[0078] S220. Under the condition that the target DC boiler is operating at a preset load within any load segment, obtain the real-time feedwater flow rate, real-time coal feed rate and test coal calorific value of the target DC boiler, and calculate the load factor corresponding to any load segment.

[0079] The preset load refers to a parameter that is manually set in advance by the target once-through boiler during operation. For example, the preset load can be represented by parameter values ​​that can be changed by the target once-through boiler under normal operating conditions according to the boiler's rated evaporation capacity and actual operating requirements. The test calorific value of the coal fed into the furnace is a parameter used to calculate the load factor corresponding to any load segment. Specifically, the calorific value of the coal fed into the furnace obtained based on relevant technologies can be used as the test calorific value of the coal fed into the furnace for calculating the load factor.

[0080] Specifically, the load factor corresponding to any load segment can be calculated by changing the value of the preset load and then calculating the load factor for that load segment corresponding to the preset load. The calculation process is shown in the following formula:

[0081]

[0082] Where, q煤 Test the calorific value of the coal fed into the furnace; M 水 For real-time water supply flow rate; M 煤 This refers to the real-time coal feed rate; f p This is the load factor.

[0083] Furthermore, by repeating the above calculation steps, the load factor corresponding to each load segment can be obtained.

[0084] S230. Establish pre-configured relationship data based on the load factor corresponding to each load segment.

[0085] For example, for ease of understanding, the pre-configured relationship data can be shown in the following table:

[0086] Table 1

[0087]

[0088] In the above implementation, for establishing pre-configured relationship data, by combining the real-time feedwater flow rate, real-time coal feed rate and tested calorific value of the coal feed rate of the target DC boiler, pre-configured relationship data can be established based on the load coefficient corresponding to each load segment.

[0089] In some implementations, the calorific value of the coal fed into the furnace is a parameter used to calculate the load factor corresponding to any load segment. For example, it can be the calorific value of the coal fed into the furnace obtained by sampling, crushing, reducing and analyzing the coal based on the real-time coal quantity when the target DC boiler is operating at a preset load within any load segment.

[0090] In some implementations, the pre-configured relationship data is established based on the load factor corresponding to each load segment. This also includes using the historical load, historical feedwater flow, historical coal input and calorific value of the target once-through boiler's coal-fired unit to correct the load factor corresponding to each load segment, thereby obtaining the corrected load factor corresponding to each load segment; and the pre-configured relationship data is established based on the corrected load factor corresponding to each load segment.

[0091] The corrected load factor for each load segment can be historical data obtained during the normal operation of the coal-fired unit, which has been verified by the historical load, historical feedwater flow, historical coal input, and calorific value of the coal input of the target once-through boiler.

[0092] Specifically, the load factor corresponding to each load segment obtained through calculation is corrected to obtain the corrected load factor for each load segment. Furthermore, the pre-configured relationship data that has been established is further refined based on the corrected load factor for each load segment. For example, the pre-configured relationship data after refining the pre-configured relationship data based on the corrected load factor for each load segment can be shown in the following table:

[0093] Table 2

[0094]

[0095]

[0096] In this embodiment, the load factor corresponding to each load segment is corrected by using the historical load, historical feedwater flow, historical coal input and calorific value of the target DC boiler's coal-fired unit, thus obtaining the corrected load factor for each load segment. The method of establishing pre-configured relational data based on the corrected load factor corresponding to each load segment can improve the accuracy of the pre-configured relational data and further reduce the deviation between the estimated and actual values ​​of the calorific value of the coal input.

[0097] This specification also provides a method for estimating the calorific value of coal fed into the furnace. Please refer to [link to relevant documentation]. Figure 3 The method includes:

[0098] S310. Calibrate the feedwater flow measurement point set at the economizer inlet and the coal feed measurement point set inside the coal feeder, and obtain the real-time feedwater flow and real-time coal feed of the target DC boiler.

[0099] S320. Determine the current load of the target DC boiler and the pre-configuration relationship data of the target DC boiler.

[0100] Specifically, the target DC boiler load is divided into different load segments; when the target DC boiler is operating at a preset load within any load segment, the real-time feedwater flow rate, real-time coal feed rate, and tested calorific value of the coal feed are obtained, and the load factor corresponding to any load segment is calculated; the preset load of the boiler is changed and the above steps are repeated to obtain all load factors within the full load segment and then corrected; a pre-configured data relationship is established based on the corrected load factors and their corresponding load segments.

[0101] S330. Determine the target load segment to which the current load belongs.

[0102] S340. Use the target load segment to search in the pre-configured relational data to obtain the current load factor.

[0103] S350. The real-time boiler water-coal ratio is determined based on the ratio between the real-time feedwater flow rate and the real-time coal feed rate.

[0104] S360. Based on the current load factor and the real-time boiler water-coal ratio, the real-time calorific value of the coal fed into the furnace is estimated.

[0105] It should be understood that although the steps in the flowchart above are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowchart above may include multiple steps or stages, which are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages in other steps.

[0106] The embodiments of this specification also provide a furnace coal calorific value estimation device 400, which includes a relational data determination module 410, a load coefficient matching module 420, a water and coal quantity acquisition module 430, and a furnace coal calorific value estimation module 440.

[0107] The relationship data determination module 410 is used to determine the current load of the target DC boiler and the pre-configured relationship data of the target DC boiler;

[0108] The load factor matching module 420 is used to perform load matching based on the current load and pre-configured relationship data to obtain the current load factor corresponding to the current load.

[0109] The water and coal quantity acquisition module 430 is used to acquire the real-time water flow rate and real-time coal input of the target DC boiler.

[0110] The calorific value estimation module 440 for coal fed into the furnace is used to estimate the real-time calorific value of coal fed into the target once-through boiler based on the current load factor, real-time feedwater flow rate and real-time coal feed amount.

[0111] In some implementations, pre-configured relationship data is used to describe the correspondence between boiler load and load factor, whereby the load factor characterizes the current load characteristics of the target DC boiler. The relationship data determination module 410 is further configured to pre-establish corresponding pre-configured relationship data for the target DC boiler and store this pre-configured relationship data in a computer device. After determining the current load of the target DC boiler, the pre-configured relationship data corresponding to the target DC boiler is retrieved from the computer device.

[0112] In some implementations, since pre-configured relational data is used to describe the correspondence between boiler load and load factor, the load factor matching module 420 is also used to match the current load with the boiler load in the pre-configured relational data to determine the matched boiler load, and the load factor corresponding to the matched boiler load is the current load factor corresponding to the current load.

[0113] In some embodiments, the target once-through boiler may include a feedwater pump, a coal feeder, and an economizer. The water and coal quantity acquisition module 430 is also used to acquire real-time feedwater flow rate through feedwater flow rate measuring points and real-time coal quantity through coal quantity measuring points located at relevant positions on the target once-through boiler. Furthermore, to obtain accurate real-time feedwater flow rate and real-time coal quantity, the feedwater flow rate measuring points and coal quantity measuring points can be calibrated in advance.

[0114] In some implementations, as analyzed above, the calorific value of the coal fed into the boiler is related to the boiler's water-to-coal ratio. Given the real-time feedwater flow rate, real-time coal feed rate, and current load factor, the coal feed rate estimation module 440 is further used to determine the real-time boiler water-to-coal ratio based on the real-time feedwater flow rate and real-time coal feed rate, thereby estimating the real-time calorific value of the target once-through boiler's coal feed based on the current load factor and the real-time boiler water-to-coal ratio. Specifically, the calorific value of the coal fed into the boiler can be determined through the following calculation method:

[0115] q 煤 =f p ·(M 水 / M 煤 )

[0116] Where, q 煤 M represents the real-time calorific value of the coal fed into the furnace. 水 For real-time water supply flow, M 煤 f is the real-time coal feed rate. p This represents the current load factor.

[0117] Specific limitations regarding the device for estimating the calorific value of coal fed into the furnace can be found in the limitations regarding the method for estimating the calorific value of coal fed into the furnace described above, and will not be repeated here. Each module in the aforementioned device for estimating the calorific value of coal fed into the furnace can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0118] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 5As shown, the computer device includes 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, mobile cellular networks, NFC (Near Field Communication), or other technologies. When executed by the processor, the computer program implements a method for estimating the calorific value of coal fed into a furnace. 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.

[0119] Those skilled in the art will understand that Figure 5 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0120] This application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the methods described above.

[0121] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0122] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0123] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for estimating the calorific value of coal fed into a furnace, characterized in that, The method includes: The current load of the target once-through boiler and its pre-configured relationship data are determined. The pre-configured relationship data describes the correspondence between boiler load and load factor. The load factor characterizes the characteristics of the current load of the target once-through boiler. The pre-configured relationship data is determined by: dividing the target once-through boiler load into different load segments, where each load segment is a fixed percentage of the boiler's maximum load value; acquiring the real-time feedwater flow rate, real-time coal feed rate, and tested calorific value of the coal feed rate when the target once-through boiler is operating at a preset load within any load segment, and calculating the load factor corresponding to each load segment; establishing the pre-configured relationship data based on the load factor corresponding to each load segment; and determining the load factor through the following methods: in, The calorific value of the coal fed into the furnace during the test; The real-time water supply flow rate; The real-time coal input rate; The load factor is mentioned above; Based on the current load and the pre-configured relationship data, load matching is performed to obtain the current load coefficient corresponding to the current load; Obtain the real-time feedwater flow rate and real-time coal feed rate of the target DC boiler; The real-time calorific value of the coal fed into the target once-through boiler is estimated based on the current load factor, the real-time feedwater flow rate, and the real-time coal feed rate.

2. The method according to claim 1, characterized in that, The process of performing load matching based on the current load and the pre-configured relationship data to obtain the current load coefficient corresponding to the current load includes: Determine the target load segment to which the current load belongs; The target load segment is used to search the pre-configured relational data to obtain the current load factor.

3. The method according to claim 1, characterized in that, The target DC boiler includes a coal feeder and an economizer; the real-time water feed rate and real-time coal input rate of the target DC boiler are obtained as follows: The real-time water flow rate is collected by a water flow measurement point set at the inlet of the economizer. The real-time coal feed rate is collected by the coal feed rate measurement point set inside the coal feeder.

4. The method according to claim 1, characterized in that, The step of estimating the real-time calorific value of the target once-through boiler coal based on the current load factor, the real-time feedwater flow rate, and the real-time coal feed rate includes: The real-time boiler water-coal ratio is determined based on the ratio between the real-time water flow rate and the real-time coal feed rate. The real-time calorific value of the coal fed into the furnace is obtained by estimating based on the current load factor and the real-time boiler water-to-coal ratio.

5. The method according to claim 4, characterized in that, The real-time calorific value of the coal fed into the furnace is determined by the following method: in, The real-time calorific value of the coal fed into the furnace; The real-time water supply flow rate; The real-time coal input rate; The current load factor is denoted as .

6. The method according to any one of claims 1 to 5, characterized in that, The load factor is related to the enthalpy increase per unit mass of feedwater in the water-cooled wall, the proportion of coal burned out in the furnace, and the proportion of heat absorbed by the water-cooled wall to the total heat absorbed by the boiler.

7. The method according to claim 1, characterized in that, The process of establishing the pre-configured relationship data based on the load factor corresponding to each load segment includes: Using the historical load, historical feedwater flow, historical coal input and calorific value of the coal-fired unit of the target DC boiler, the load factor corresponding to each load segment is corrected to obtain the corrected load factor corresponding to each load segment. The pre-configured relationship data is established based on the corrected load factor corresponding to each load segment.

8. The method according to claim 1, characterized in that, The calorific value of the coal fed into the furnace is obtained by sampling, crushing, reducing and analyzing the real-time coal feed amount.

9. A device for estimating the calorific value of coal fed into a furnace, characterized in that, The device includes: A relationship data determination module is used to determine the current load of the target DC boiler and the pre-configured relationship data of the target DC boiler. The pre-configured relationship data describes the correspondence between boiler load and load factor. The load factor characterizes the characteristics of the current load of the target DC boiler when its current load is determined. The pre-configured relationship data is determined by: dividing the target DC boiler load into different load segments, where each load segment is a fixed percentage of the boiler's maximum load value; acquiring the real-time feedwater flow rate, real-time coal feed rate, and tested calorific value of the coal feed rate of the target DC boiler when it is operating at a preset load within any load segment, and calculating the load factor corresponding to each load segment; establishing the pre-configured relationship data based on the load factor corresponding to each load segment; and determining the load factor by: in, The calorific value of the coal fed into the furnace during the test; The real-time water supply flow rate; The real-time coal input rate; The load factor is mentioned above; The load factor matching module is used to perform load matching based on the current load and the pre-configured relationship data to obtain the current load factor corresponding to the current load. The water and coal quantity acquisition module is used to acquire the real-time water flow rate and real-time coal input quantity of the target DC boiler. The coal calorific value estimation module is used to estimate the real-time coal calorific value of the target once-through boiler based on the current load factor, the real-time feedwater flow rate, and the real-time coal feed amount.

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