Self-adaptive regulation and control method and device for water-fuel ratio of once-through boiler

Abstract

The invention relates to the field of industrial automation control, and provides a self-adaptive regulation and control method and device for the water-fuel ratio of a once-through boiler. The method comprises the steps that if it is determined that the current actual water supply amount, the current actual fuel amount and the current actual load are all normal values, and preset water-fuel ratio self-adaptive regulation and control triggering conditions are met, a backward deduction time period is determined; based on the current actual water supply amount, the current actual fuel amount, the current actual load, the current target load and the backward deduction time period, the current target water supply amount, the current target fuel amount and the current target water-fuel ratio of the once-through boiler in the current period are calculated; and based on the current target water supply amount, the current target fuel amount and the current target water-fuel ratio, the current actual water supply amount and the current actual fuel amount are subjected to self-adaptive regulation and control. According to the method, the problem of imbalance of the water-coal ratio caused by coal quality change, instrument measurement error change and the like can be solved, the traditional complex water-coal ratio mutual override control logic is not needed, the coal quality change is adaptive, and the robustness is better.

Description

Technical Field

[0001] The present application relates to the field of industrial automation control, and in particular to a method and device for adaptively controlling the water-fuel ratio of a direct current boiler. Background Art

[0002] Water-coal ratio (water-fuel ratio) control is the main control method for air temperature regulation of direct current boilers. When the coal quality is poor, the water-coal ratio will decrease; when the coal quality is good, the water-coal ratio will increase. When the coal quality changes greatly, it is necessary to release the automatic control and manually control the water supply to ensure that the intermediate point temperature is basically normal and the air temperature is stable.

[0003] The traditional water-coal ratio control method uses a fixed broken line function (determined during commissioning based on the boiler design coal type) and relies on BTU thermal correction to overcome coal quality changes within a certain range based on load deviation (or main steam pressure deviation). When the coal quality is stable, the water-coal ratio is relatively fixed and can meet power generation needs. However, when the coal quality, coal quantity and feed water flow rate change greatly, it is easy to cause water-coal ratio imbalance, and water-coal cross-restriction does not work, thus affecting the investment of combustion automation and feed water automation control. Summary of the invention

[0004] In view of this, an embodiment of the present application provides a method and device for adaptively controlling the water-fuel ratio of a direct current boiler to solve the problem in the prior art that when the coal quality, coal quantity and water feed flow rate change greatly, the water-coal ratio is easily imbalanced, and the water-coal cross-restriction does not work, thereby affecting the investment in automatic combustion and automatic water feed control.

[0005] A first aspect of an embodiment of the present application provides a method for adaptively controlling the water-fuel ratio of a once-through boiler, comprising:

[0006] Determine the current actual feed water quantity, the current actual fuel quantity, the current actual load and the current target load of the once-through boiler in the current cycle;

[0007] If it is determined that the current actual water supply, the current actual fuel quantity and the current actual load are all normal values ​​and meet the preset water-fuel ratio adaptive control triggering conditions, then the backward time period is determined, and the backward time period is a historical time period of a preset length starting from the current cycle;

[0008] Based on the current actual feed water quantity, the current actual fuel quantity, the current actual load, the current target load and the backward time period, calculate the current target feed water quantity, the current target fuel quantity and the current target water-fuel ratio of the direct current boiler in the current cycle;

[0009] Based on the current target water supply amount, the current target fuel amount and the current target water-fuel ratio, the current actual water supply amount and the current actual fuel amount are adaptively controlled.

[0010] A second aspect of the embodiment of the present application provides a once-through boiler water-fuel ratio adaptive control device, comprising:

[0011] A first determination module is configured to determine a current actual feed water amount, a current actual fuel amount, a current actual load and a current target load of the once-through boiler in a current cycle;

[0012] The second determination module is configured to determine a backward time period if it is determined that the current actual water supply, the current actual fuel amount and the current actual load are all normal values ​​and meet the preset water-fuel ratio adaptive control triggering conditions, and the backward time period is a historical time period of a preset length from the current cycle forward;

[0013] A calculation module is configured to calculate a current target feedwater amount, a current target fuel amount, and a current target water-fuel ratio of the direct current boiler in a current cycle based on a current actual feedwater amount, a current actual fuel amount, a current actual load, a current target load, and a backward time period;

[0014] The control module is configured to adaptively control the current actual water supply amount and the current actual fuel amount based on the current target water supply amount, the current target fuel amount and the current target water-fuel ratio.

[0015] According to a third aspect of an embodiment of the present application, an electronic device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the computer program.

[0016] According to a fourth aspect of an embodiment of the present application, a readable storage medium is provided, which stores a computer program, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0017] Compared with the prior art, the beneficial effects of the embodiments of the present application include at least: by calculating the current target water supply, current target fuel amount and current target water-fuel ratio of the direct current boiler in the current cycle based on the current actual water supply, current actual fuel amount, current actual load, current target load and backward time period, when the current actual water supply, current actual fuel amount and current actual load are all normal values ​​and the preset water-fuel ratio adaptive control trigger conditions are met; then, based on the current target water supply, current target fuel amount and current target water-fuel ratio, the current actual water supply and the current actual fuel amount are adaptively controlled, which can overcome the problem of water-coal ratio imbalance caused by changes in coal quality, changes in instrument measurement errors, etc., and does not require the traditional complex water-coal ratio mutual override control logic, and has better adaptability and robustness to coal quality changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 It is a flow chart of a method for adaptively controlling the water-fuel ratio of a direct-flow boiler provided in an embodiment of the present application;

[0020] Figure 2 This is a schematic diagram of a method for determining a backward time period provided in an embodiment of the present application;

[0021] Figure 3 It is a flow chart of a method for calculating a current water consumption target value provided by an embodiment of the present application;

[0022] Figure 4 is a flow chart of a method for calculating a current fuel consumption target value provided in an embodiment of the present application;

[0023] Figure 5 is a flow chart of a method for calculating a current target water-fuel ratio provided in an embodiment of the present application;

[0024] Figure 6 It is a structural schematic diagram of a once-through boiler water-fuel ratio adaptive control device provided in an embodiment of the present application;

[0025] Figure 7 It is a structural schematic diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0027] A method and device for adaptively controlling the water-fuel ratio of a direct current boiler according to an embodiment of the present application will be described in detail below with reference to the accompanying drawings.

[0028] The water-coal ratio (water-fuel ratio) of a DC boiler is the advanced control signal for the main steam temperature regulation. The regulation of the DC boiler temperature mainly depends on the water-coal ratio, and the cooling water is an auxiliary means of regulation. The water supply of the unit must first meet the unit load demand, because the water supply of the DC boiler is equal to the evaporation amount. Secondly, the coal quantity must meet the needs of the unit load, main gas pressure and main steam temperature. Cooling water is used for precise adjustment of the main temperature. The water supply of the DC boiler is unchanged at the initial start-up, which is mainly to meet the minimum cooling flow of the water-cooled wall at the initial start-up. In the later stage, after the boiler reaches DC operation, the water supply and coal supply increase in a certain ratio. Of course, when the coal quality changes, the water-coal ratio is different.

[0029] When the coal quality, coal quantity and water supply flow rate change greatly, the traditional water-coal ratio control method will have water-coal ratio imbalance, and the water-coal cross restriction will not work, thus affecting the investment of automatic combustion and automatic water supply control.

[0030] Based on this, the present application proposes a method for adaptively controlling the water-fuel ratio of a direct current boiler. This method does not require setting a water-coal ratio function during debugging. Instead, it performs real-time iteration to calculate the current target water feed, current target fuel amount and current target water-fuel ratio of the direct current boiler in the current cycle based on the backward time period before the current cycle, the current actual water feed, the current actual fuel amount, the current actual load and the current target load; then the current actual water feed and the current actual fuel amount are adaptively controlled according to the current target water feed, the current target fuel amount and the current target water-fuel ratio. This method has better robustness. Even if the coal quality changes greatly, the measurement deviations of the coal amount and water feed flow are large, and the drift caused by the instrument measurement is large, etc., it can all be adaptively controlled without affecting the automatic combustion and water feed.

[0031] Figure 1 It is a flow chart of a method for adaptively controlling the water-fuel ratio of a direct current boiler provided in an embodiment of the present application. Figure 1 The adaptive control method of water-fuel ratio of direct current boiler can be executed by the combustion control system in the DCS system. Figure 1 As shown, the method for adaptively controlling the water-fuel ratio of a direct-flow boiler may specifically include the following steps:

[0032] Step S101, determining the current actual feed water amount, the current actual fuel amount, the current actual load and the current target load of the direct current boiler in the current cycle.

[0033] A once-through boiler is a boiler that relies on the pressure of the feed water pump to sequentially pass the feed water through the economizer, evaporation heating surface (water-cooled wall), and superheater, and all of them are converted into superheated steam. General boilers have steam drums, but once-through boilers do not. Once-through boilers are used in the boilers of supercritical and ultra-supercritical units.

[0034] The ultra-supercritical and supercritical units of thermal power plants refer to units whose parameters of the working fluid in the boiler reach or exceed the critical pressure. The working fluid in the boiler is water, the critical pressure of water is 22.129MPa, and the critical temperature is 374.15℃; at this pressure and temperature, the density of water expanded by high temperature and water vapor compressed by high pressure is the same, which is called the critical point of water. If the working fluid pressure in the furnace is lower than this pressure, it is called a subcritical boiler, and if it is greater than this pressure, it is a supercritical boiler. The steam temperature in the furnace is not lower than 593℃ or the steam pressure is not lower than 31MPa, which is called ultra-supercritical. In engineering, those above 25MPa are often called ultra-supercritical.

[0035] The current actual feed water volume refers to the actual feed water flow entering the direct current boiler during the current cycle, which can generally be measured by an orifice plate and supporting detection instruments.

[0036] The current actual fuel quantity refers to the amount of fuel (such as coal) entering the direct current boiler during the current cycle, which can generally be measured by a fuel detection instrument.

[0037] The current actual load refers to the actual heat load of the DC boiler in the current cycle. The current target load refers to the target heat load of the DC boiler in the current cycle. The heat load of the boiler refers to the amount of heat that the boiler can generate per unit time.

[0038] Step S102, if it is determined that the current actual water supply, the current actual fuel amount and the current actual load are all normal values ​​and meet the preset water-fuel ratio adaptive control trigger conditions, then determine the backward time period, which is a historical time period of a preset length starting from the current cycle.

[0039] The preset water-fuel ratio adaptive control trigger condition can be a user manually triggering a preset "calculation switch (SW)" button / pop-up window, etc., or it can be automatically triggered by the combustion control system to trigger a preset "calculation switch (SW)" button / pop-up window, etc.

[0040] The combustion control system is a general term for analog control systems that adapt the energy of fuel combustion in the furnace to the needs of the boiler load and maintain safe, stable and economical operation of the boiler. It is usually composed of fuel quantity control module, water supply control module, air supply volume control module, induced draft control module, temperature control module, load control module, etc.

[0041] The combustion control system can be deployed in a DCS (Distributed Control System). DCS is a multi-level computer system consisting of a process control level and a process monitoring level with a communication network as the link. It integrates 4C technologies such as computer, communication, display and control. Its basic idea is decentralized control, centralized operation, hierarchical management, flexible configuration and convenient configuration.

[0042] Whether the current actual water supply is a normal value can be determined in the following ways. The first way, ① first, determine whether the current actual water supply is within the preset normal water supply range (which can be flexibly set according to actual conditions). ② Then, if the current actual water supply is within the preset normal water supply range, and whether the current actual water supply jumps near the critical value of the preset normal water supply range (for example, the current actual water supply jumps near the upper limit or lower limit of the normal water supply), then further determine whether the jump of the current actual water supply is within the normal jump range (which can be flexibly set according to actual conditions). Steps ① and ② are performed successively. If the jump of the current actual water supply is within the normal jump range, it is determined that the current actual water supply is a normal value. If the current actual water supply is not within the preset normal water supply range, it is determined that the current actual water supply is an abnormal value. If the current actual water supply is within the preset normal water supply range, and the current actual water supply is the critical value of the preset normal water supply range, but the jump of the current actual water supply is not within the normal jump range, then the current actual water supply is determined to be an abnormal value.

[0043] The second method is: ① determine whether the current actual water supply is within the preset normal water supply range; ② when the current actual water supply jumps near the critical value of the preset normal water supply range, determine whether the jump of the current actual water supply is within the normal jump range. Step ① and step ② are performed in parallel. If the current actual water supply is within the preset normal water supply range, and the current actual water supply jumps near the critical value of the preset normal water supply range, and the jump of the current actual water supply is within the normal jump range, then the current actual water supply is determined to be a normal value. If the current actual water supply is within the preset normal water supply range, and the current actual water supply is not the critical value of the preset normal water supply range, then the current actual water supply is determined to be a normal value. If the current actual water supply is not within the preset normal water supply range, and / or the jump of the current actual water supply is not within the normal jump range, then the current actual water supply is determined to be an abnormal value.

[0044] The first method or the second method can be used to determine whether the current actual water supply is a normal value. Compared with the second method, the first method is conducive to saving computing resources and improving computing efficiency.

[0045] It should be noted that the above-mentioned implementation can be referred to to determine whether the current actual fuel quantity and the current actual load are normal values, which will not be described in detail here.

[0046] Before performing statistical calculations on the current target water feed, the current target fuel quantity and the current target water-fuel ratio of the direct current boiler in the current cycle, first determine whether the current actual water feed, the current actual fuel quantity and the current actual load are normal values. This can improve the accuracy and reliability of subsequent statistical calculation results, and is beneficial to improving the adaptability of regulating the current actual water feed and the current actual fuel quantity, and overcoming the problem of water-coal ratio imbalance caused by measurement errors due to changes in fuel calorific value, fuel quantity and water feed flow due to temperature and humidity deviations in the morning and evening, and in winter and summer.

[0047] Step S103, based on the current actual feed water quantity, the current actual fuel quantity, the current actual load, the current target load and the backward time period, calculate the current target feed water quantity, the current target fuel quantity and the current target water-fuel ratio of the direct current boiler in the current cycle.

[0048] The current target feed water volume refers to the target feed water flow entering the direct current boiler during the current cycle.

[0049] The current target fuel quantity refers to the target fuel quantity entering the direct current boiler in the current cycle.

[0050] The water-fuel ratio refers to the ratio of the amount of fuel (such as coal, etc.) entering the direct current boiler to the amount of feed water (feed water flow).

[0051] The current target water-fuel ratio refers to the target ratio of the amount of fuel entering the direct current boiler to the amount of feed water (feed water flow) during the current cycle.

[0052] Step S104, based on the current target water supply amount, the current target fuel amount and the current target water-fuel ratio, the current actual water supply amount and the current actual fuel amount are adaptively regulated.

[0053] The technical solution provided in the embodiment of the present application calculates the current target water feed amount, the current target fuel amount and the current target water-fuel ratio of the direct current boiler in the current cycle based on the current actual water feed amount, the current actual fuel amount, the current actual load, the current target load and the backward time period, when the current actual water feed amount, the current actual fuel amount and the current actual load are all normal values ​​and the preset water-fuel ratio adaptive control trigger conditions are met; then, based on the current target water feed amount, the current target fuel amount and the current target water-fuel ratio, the current actual water feed amount and the current actual fuel amount are adaptively controlled, which can overcome the problem of water-coal ratio imbalance caused by changes in coal quality, changes in instrument measurement errors, etc., and does not require the traditional complex water-coal ratio mutual override control logic, and has better adaptability and robustness to coal quality changes.

[0054] In some embodiments, determining the backward time period includes:

[0055] Determine the operating condition type of the once-through boiler in the current cycle;

[0056] If the working condition type is a stable working condition, the historical time period of the first preset time period is reversed from the current period to be determined as the reverse time period;

[0057] If the operating condition type is a variable operating condition, a historical time period of a second preset time length reversed from the current cycle is determined as the reverse time period, wherein the first preset time length is greater than the second preset time length.

[0058] The operating condition type is related to the change in the fuel calorific value of the direct current boiler in the current cycle. Generally, when the fuel calorific value changes greatly, it is a variable operating condition; when the fuel calorific value changes slightly, it is a stable operating condition. The degree of change in the fuel calorific value can be identified based on the oxygen deviation and load deviation (main steam pressure deviation) of the direct current boiler.

[0059] The first preset duration can be set according to actual conditions and is generally set to 120 minutes.

[0060] The second preset duration can be set according to actual conditions and is generally set to 40 minutes.

[0061] As an example, see Figure 2 , if the operating condition type of the direct current boiler in the current cycle is a stable operating condition, then the historical time period of the first preset duration (such as 120 minutes) from the current cycle is determined as the reverse time period. That is, the 120 minutes before the current cycle (current moment) is determined as the reverse time period. If the operating condition type of the direct current boiler in the current cycle is a variable operating condition, then the historical time period of the second preset duration (such as 40 minutes) from the current cycle is determined as the reverse time period. That is, the 40 minutes before the current cycle (current moment) is determined as the reverse time period.

[0062] The backward calculation period generally does not exceed 120 minutes.

[0063] In some embodiments, based on the current actual feed water amount, the current actual fuel amount, the current actual load, the current target load and the backward time period, the current target feed water amount, the current target fuel amount and the current target water-fuel ratio of the direct current boiler in the current cycle are calculated, including:

[0064] Calculate the current target feed water volume of the direct-flow boiler in the current cycle according to the current actual feed water volume, the current actual load, the current target load, the backward time period and the feed water volume control value of the previous cycle;

[0065] Calculate the current target fuel quantity of the direct current boiler in the current cycle according to the current actual fuel quantity, the current actual load, the current target load, the backward time period and the fuel quantity control value of the previous cycle;

[0066] According to the current actual water supply, the current actual fuel quantity, the backward time period and the water-fuel ratio control value of the previous cycle, the current target water-fuel ratio of the direct current boiler in the current cycle is calculated.

[0067] In some embodiments, the current target feed water volume of the once-through boiler in the current cycle is calculated based on the current actual feed water volume, the current actual load, the current target load, the backward time period and the feed water volume control value of the previous cycle, including:

[0068] According to the feed water control value of the backward time period and the previous cycle, the historical water consumption value of the once-through boiler in the backward time period is calculated;

[0069] Determine the current water consumption weight value, and calculate the current water consumption value of the direct current boiler in the current cycle according to the current actual water supply, the current actual load and the current water consumption weight value;

[0070] Calculate the current water consumption target value of the direct-flow boiler in the current cycle based on the historical water consumption value and the current water consumption value;

[0071] Based on the current water consumption target value and the current target load, the current target feed water volume of the direct current boiler in the current cycle is calculated.

[0072] Figure 3 A flow chart of a method for calculating a current water consumption target value provided in an embodiment of the present application.

[0073] See also Figure 3 , the method for calculating the current water consumption target value may include the following steps:

[0074] Step S301, determining whether the current actual water supply (denoted as I1) and the current actual load (denoted as I2) are both normal values.

[0075] Step S302, if the current actual water supply and the current actual load are both normal values, it is determined whether the configuration parameter value of the calculation switch (denoted as SW) is 1 (or whether it is TRUE). Among them, SW = 1 (or SW = TRUE), indicating that the preset water-fuel ratio adaptive control trigger condition is met; SW ≠ 1 (or SW = FALSE), indicating that the preset water-fuel ratio adaptive control trigger condition is not met.

[0076] Step S303, if the configuration parameter of the calculation switch is 1 (SW=1 (or SW=TRUE)), reset Y1 to the current actual water consumption (I1 / I2) of the current cycle, that is, set Y1:=I1 / I2, and jump to step S305.

[0077] Step S304, if the configuration parameter of the calculation switch is not 1 (SW≠1 (or SW=FALSE)), then Y1 is maintained, can be assigned, and jump to step S305. Y1 is the initial value of the statistical calculation, which can be maintained or assigned to the current actual water consumption (I1 / I2), or maintained or assigned to a preset initial value of an ideal state, representing the water consumption value of the past statistical calculation, which can save the time of statistical calculation.

[0078] Step S305, statistically calculate O1 and output O1; specifically, let O1: = (RT*120*Y+M*(I1 / I2)) / (RT*120+M). In the formula, RT represents the duration of the backward time period, which is usually 40 minutes to 120 minutes. 120 means that the calculation cycle is 500ms, and 120 calculations are performed in 1 minute. Y represents the water supply control value of the previous cycle calculated by statistics. M represents the current water consumption weight value, which is 1 by default; the larger the current water consumption weight value, the faster the statistics will approach the current value (current actual water consumption), and the faster the control speed; the current water consumption weight value can range from 1 to 10. I1 represents the current actual water supply. I2 represents the current actual load. O1 represents the current water consumption target value calculated by statistics.

[0079] Step S306, set Y:=O1, and record Y, end the statistical calculation of the current cycle, and wait to enter the next cycle (next statistical calculation cycle) to statistically calculate the current water consumption target value. In the embodiment of the present application, a statistical calculation cycle (adaptive control cycle) is generally 100 milliseconds or 500 milliseconds.

[0080] Next, the current water consumption target value O1 obtained by the above statistical calculation is multiplied by the current target load to obtain the current target water supply of the direct current boiler in the current cycle.

[0081] The method for calculating the current water consumption target value in the embodiment of the present application can be written in ST (Structured text, structured text / structured file programming language) text structure language and encapsulated into function blocks for other program calls.

[0082] In the above implementation, the historical water consumption value is "RT*120*Y" and the current water consumption value is "M*(I1 / I2)".

[0083] In some embodiments, determining the current water consumption weight value includes:

[0084] Determine the change in fuel calorific value for once-through boilers;

[0085] The current water consumption weight value is determined according to the change value of the fuel calorific value, wherein the greater the change value of the fuel calorific value is, the greater the current water consumption weight value is.

[0086] The fuel calorific value change value represents the change in the calorific value of the fuel of the direct current boiler, for example, the change in the calorific value of coal.

[0087] As an example, a mapping relationship table of "fuel calorific value change value-current water consumption weight value" can be preset, and then the mapping relationship table can be queried to determine the current water consumption weight value corresponding to the fuel calorific value change value.

[0088] Exemplarily, the mapping relationship table of “fuel calorific value change value-current water consumption weight value” is shown in Table 1.

[0089] Table 1 Mapping relationship table of "Fuel calorific value change value-current water consumption weight value"

[0090] Fuel calorific value change <![CDATA[ΔH1]]> <![CDATA[ΔH2]]> ... <![CDATA[ΔH n ]]> Current water consumption weight value <![CDATA[W1]]> <![CDATA[W2]]> ... <![CDATA[W n ]]>

[0091] As an example, assuming that the fuel calorific value change value is ΔH1, the current water consumption weight value can be determined by querying the above Table 1.

[0092] Figure 4 It is a flow chart of a method for calculating the current fuel consumption target value provided in an embodiment of the present application.

[0093] Figure 5 It is a flow chart of a method for calculating the current target water-fuel ratio provided in an embodiment of the present application.

[0094] Among them, the calculation process of the current fuel consumption target value and the current target water-fuel ratio is basically the same as the calculation process of the current target water supply amount in the above embodiment, and will not be repeated here.

[0095] It should be noted that Figure 4 In the table, I1 and I2 represent the current actual fuel quantity and the current actual load, respectively. Y1 is the initial value of the statistical calculation, which can be maintained or assigned as the current actual fuel consumption (I1 / I2), or maintained or assigned as a preset initial value of an ideal state, representing the fuel consumption value of the past statistical calculation, which can save the time of statistical calculation. RT represents the length of the reverse time period, which is usually 40 minutes to 120 minutes. 120 means that the calculation cycle is 500ms, and 120 calculations are performed in 1 minute. Y represents the fuel quantity control value of the previous cycle calculated by statistics. M represents the current fuel consumption weight value, which is 1 by default; the larger the current fuel consumption weight value, the faster the statistics will approach the current value (current actual fuel consumption), and the faster the control speed; the value range of the current fuel consumption weight value can be 1 to 10. O1 represents the current fuel consumption target value calculated by statistics.

[0096] Figure 5In the table, I1 and I2 represent the current actual water supply and the current actual fuel respectively. Y1 is the initial value of the statistical calculation, which can be maintained or assigned as the current water-fuel ratio (I1 / I2), or maintained or assigned as a pre-set initial value of an ideal state, representing the water-fuel ratio of the past statistical calculation, which can save the time of statistical calculation. RT represents the length of the reverse time period, which is usually 40 minutes to 120 minutes. 120 means that the calculation cycle is 500ms, and 120 calculations are performed in 1 minute. Y represents the water-fuel ratio control value of the previous cycle calculated by statistics. M represents the current water-fuel ratio weight value, which is 1 by default; the larger the current water-fuel ratio weight value, the faster the statistics will approach the current value (current actual fuel consumption), and the faster the control speed; the current water-fuel ratio weight value can range from 1 to 10. O1 represents the current target water-fuel ratio calculated by statistics.

[0097] The method for calculating the current fuel consumption target value and the method for calculating the current target water-fuel ratio in the embodiment of the present application can be written in ST text structure language and encapsulated into function blocks for calling by other programs.

[0098] In some embodiments, based on the current target water supply amount, the current target fuel amount and the current target water-fuel ratio, the current actual water supply amount and the current actual fuel amount are adaptively regulated, including:

[0099] Based on the midpoint temperature of the once-through boiler in the current cycle, the current target water supply amount, the current target fuel amount and the current target water-fuel ratio are corrected to obtain the current corrected target water supply amount, the current corrected target fuel amount and the current corrected target water-fuel ratio;

[0100] Based on the current corrected target water supply amount, the current corrected target fuel amount and the current corrected target water-fuel ratio, the current actual water supply amount and the current actual fuel amount are adaptively controlled.

[0101] During the operation of a direct current boiler, any change in the amount of feed water and fuel or in the coal quality will lead to a significant change in the outlet steam temperature (change in the fuel / water ratio). For this reason, a fixed temperature point should be selected for monitoring, and it should be maintained at a temperature corresponding to the load under different loads. Then, it should be fine-tuned by spraying water to reduce the temperature, so as to ensure the stability of the superheater outlet temperature. If this point is selected too far back, it will not be able to quickly reflect changes in the fuel-water ratio and coal quality. If it is too far forward, the steam temperature will be too delayed. The separator outlet temperature can quickly reflect changes in the fuel-water ratio and coal quality, and can promptly reflect changes in the steam temperature. Therefore, the separator outlet is generally taken as the temperature monitoring point, also known as the intermediate point temperature.

[0102] As an example, the current target water supply, current target fuel quantity and current target water-fuel ratio calculated above can be corrected by the midpoint temperature deviation correction machine based on the midpoint temperature of the direct current boiler in the current cycle, so as to obtain the current corrected target water supply, current corrected target fuel quantity and current corrected target water-fuel ratio. If the midpoint temperature decreases, it means that the current target water-fuel ratio is too large, and the current target water-fuel ratio can be appropriately reduced (for example, the current target water supply can be appropriately reduced, or the current target fuel quantity can be appropriately increased); if the midpoint temperature increases, it means that the current target water-fuel ratio is too small, and the current target water-fuel ratio can be appropriately increased (for example, the current target fuel quantity can be appropriately reduced, or the current target water supply can be appropriately increased).

[0103] In some embodiments, based on the current corrected target water supply amount, the current corrected target fuel amount and the current corrected target water-fuel ratio, the current actual water supply amount and the current actual fuel amount are adaptively regulated, including:

[0104] Calculate the water supply deviation value between the current corrected target water supply and the current actual water supply;

[0105] Calculating a fuel quantity deviation value between a current corrected target fuel quantity and a current actual fuel quantity;

[0106] Calculate the current actual water-fuel ratio of the direct-flow boiler in the current cycle according to the current actual feed water amount and the current actual fuel amount;

[0107] The current actual water supply amount is adaptively regulated based on the water supply amount deviation value, and the current actual fuel amount is adaptively regulated based on the fuel amount deviation value, so that the current actual water-fuel ratio is adaptively adjusted to the current corrected target water-fuel ratio.

[0108] The water supply deviation value D can be calculated according to formula (1): Water .

[0109] D Water =Water tar -Water act (1);

[0110] In formula (1), Water tar Indicates the current corrected target water supply, Water act Indicates the current actual water supply, D Water Indicates the water supply deviation value.

[0111] The fuel quantity deviation value D can be calculated according to formula (2): Fuel .

[0112] D Fuel =Fuel tar -Fuel act(2);

[0113] In formula (2), Fuel tar Indicates the current corrected target fuel amount, Fuel act Indicates the current actual fuel quantity, D Fuel Indicates the fuel quantity deviation value.

[0114] The current actual water-fuel ratio of the direct current boiler in the current cycle is the ratio between the current actual feed water amount and the current actual fuel amount.

[0115] The current corrected target water-fuel ratio of the direct current boiler in the current cycle is the ratio between the current corrected target feed water volume and the current corrected target fuel volume.

[0116] As an example, in a DCS system, the combustion control system can be based on the above DCS system. Water Water act Perform adaptive regulation to make Water act Gradually moving towards Water tar At the same time, based on the above D Fuel Fuel act Perform adaptive control to make Fuel act Gradually moving towards Fuel tar At the same time, through the act 、Fuel act The adaptive adjustment of Gradually tending to

[0117] Compared with the traditional PID control method, the adaptive control method of the embodiment of the present application has the advantages of smaller adjustment lag, higher control accuracy, better system robustness, etc.

[0118] In summary, the technical solution provided by the embodiment of the present application utilizes a genetic algorithm to perform big data analysis in a DCS system, and performs real-time iteration based on the backward time period before the current cycle of the DC boiler, the current actual water supply, the current actual fuel quantity, the current actual load, and the current target load to calculate the current target water supply, the current target fuel quantity, and the current target water-fuel ratio of the DC boiler in the current cycle; and then adaptively control the current actual water supply and the current actual fuel quantity according to the current target water supply, the current target fuel quantity, and the current target water-fuel ratio. Through the above-mentioned method, the current actual water supply, the current actual fuel quantity, and the current actual water-fuel ratio of the DC boiler can be continuously iterated and corrected, thereby effectively overcoming the water-coal ratio imbalance caused by the measurement errors caused by the changes in the calorific value of the fuel, the fuel quantity, and the water supply flow due to the temperature and humidity deviations in the morning and evening, winter and summer, without affecting the combustion automation and water supply automation, and having better robustness. At the same time, through optimal judgment, the combustion economy is better.

[0119] All the above optional technical solutions can be arbitrarily combined to form optional embodiments of the present application, which will not be described one by one here.

[0120] The following are device embodiments of the present application, which can be used to execute the method embodiments of the present application. For details not disclosed in the device embodiments of the present application, please refer to the method embodiments of the present application.

[0121] Figure 6 Schematic diagram of a structure of a direct-flow boiler water-fuel ratio adaptive control device provided in an embodiment of the present application. Figure 6 As shown, the once-through boiler water-fuel ratio adaptive control device includes:

[0122] The first determination module 601 is configured to determine the current actual feed water amount, the current actual fuel amount, the current actual load and the current target load of the once-through boiler in the current cycle;

[0123] The second determination module 602 is configured to determine a backward time period if it is determined that the current actual water supply amount, the current actual fuel amount and the current actual load are all normal values ​​and meet the preset water-fuel ratio adaptive control triggering condition, and the backward time period is a historical time period of a preset length from the current cycle forward;

[0124] The calculation module 603 is configured to calculate the current target feed water amount, the current target fuel amount and the current target water-fuel ratio of the once-through boiler in the current cycle based on the current actual feed water amount, the current actual fuel amount, the current actual load, the current target load and the backward time period;

[0125] The control module 604 is configured to adaptively control the current actual water supply amount and the current actual fuel amount based on the current target water supply amount, the current target fuel amount and the current target water-fuel ratio.

[0126] In some embodiments, the second determination module 602 includes a determination unit, and the determination unit may be configured to: determine a backward time period.

[0127] The determining unit may specifically include:

[0128] An operating condition determination component is configured to determine an operating condition type of the once-through boiler in a current cycle;

[0129] A first determining component is configured to determine, if the operating condition type is a stable operating condition, a historical time period of a first preset time period backward from the current cycle as a backward time period;

[0130] The second determination component is configured to determine a historical time period of a second preset time period backward from the current cycle as a backward time period if the operating condition type is a variable operating condition, wherein the first preset time period is greater than the second preset time period.

[0131] In some embodiments, the calculation module 603 includes:

[0132] The first calculation unit is configured to calculate the current target water supply of the direct current boiler in the current cycle according to the current actual water supply, the current actual load, the current target load, the backward time period and the water supply control value of the previous cycle;

[0133] The second calculation unit is configured to calculate the current target fuel quantity of the direct current boiler in the current cycle according to the current actual fuel quantity, the current actual load, the current target load, the backward time period and the fuel quantity control value of the previous cycle;

[0134] The third calculation unit is configured to calculate the current target water-fuel ratio of the direct current boiler in the current cycle based on the current actual water supply, the current actual fuel amount, the backward time period and the water-fuel ratio control value of the previous cycle.

[0135] In some embodiments, the first computing unit includes:

[0136] The first calculation component is configured to calculate the historical water consumption value of the direct current boiler in the backward time period according to the backward time period and the feed water control value of the previous cycle;

[0137] A second calculation component is configured to determine a current water consumption weight value, and calculate a current water consumption value of the direct current boiler in a current cycle according to a current actual water supply, a current actual load and a current water consumption weight value;

[0138] A third calculation component is configured to calculate a current water consumption target value of the once-through boiler in a current cycle according to the historical water consumption value and the current water consumption value;

[0139] The fourth calculation component is configured to calculate the current target water supply of the direct current boiler in the current cycle based on the current water consumption target value and the current target load.

[0140] In some embodiments, the second calculation component includes a determination device, which can be configured to determine a current water consumption weight value.

[0141] The determining device may be specifically configured as follows:

[0142] Determine the change in fuel calorific value for once-through boilers;

[0143] The current water consumption weight value is determined according to the change value of the fuel calorific value, wherein the greater the change value of the fuel calorific value is, the greater the current water consumption weight value is.

[0144] In some embodiments, the control module 604 includes:

[0145] a correction unit configured to correct a current target feedwater amount, a current target fuel amount, and a current target water-fuel ratio based on a midpoint temperature of the once-through boiler in a current cycle to obtain a current corrected target feedwater amount, a current corrected target fuel amount, and a current corrected target water-fuel ratio;

[0146] The control unit is configured to adaptively control the current actual water supply amount and the current actual fuel amount based on the current corrected target water supply amount, the current corrected target fuel amount and the current corrected target water-fuel ratio.

[0147] In some embodiments, the above-mentioned control unit may be specifically configured as follows:

[0148] Calculate the water supply deviation value between the current corrected target water supply and the current actual water supply;

[0149] Calculating a fuel quantity deviation value between a current corrected target fuel quantity and a current actual fuel quantity;

[0150] Calculate the current actual water-fuel ratio of the direct-flow boiler in the current cycle according to the current actual feed water amount and the current actual fuel amount;

[0151] The current actual water supply amount is adaptively regulated based on the water supply amount deviation value, and the current actual fuel amount is adaptively regulated based on the fuel amount deviation value, so that the current actual water-fuel ratio is adaptively adjusted to the current corrected target water-fuel ratio.

[0152] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0153] Figure 7Schematic diagram of an electronic device 7 provided in an embodiment of the present application. Figure 7 As shown, the electronic device 7 of this embodiment includes: a processor 701, a memory 702, and a computer program 703 stored in the memory 702 and executable on the processor 701. When the processor 701 executes the computer program 703, the steps in the above-mentioned method embodiments are implemented. Alternatively, when the processor 701 executes the computer program 703, the functions of the modules / units in the above-mentioned device embodiments are implemented.

[0154] The electronic device 7 may be a desktop computer, a notebook, a PDA, a cloud server, or other electronic device. The electronic device 7 may include, but is not limited to, a processor 701 and a memory 702. Those skilled in the art will appreciate that Figure 7 The electronic device 7 is merely an example and does not limit the electronic device 7 , and may include more or less components than those shown in the figure, or different components.

[0155] The processor 701 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0156] The memory 702 may be an internal storage unit of the electronic device 7, for example, a hard disk or memory of the electronic device 7. The memory 702 may also be an external storage device of the electronic device 7, for example, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the electronic device 7. The memory 702 may also include both an internal storage unit of the electronic device 7 and an external storage device. The memory 702 is used to store computer programs and other programs and data required by the electronic device.

[0157] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units.

[0158] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium (e.g., a computer-readable storage medium). Based on this understanding, the present application implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. The computer program may include computer program code, which may be in source code form, object code form, executable file or some intermediate form. Computer-readable storage media may include: any entity or device capable of carrying computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc.

[0159] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for adaptively controlling the water-fuel ratio of a once-through boiler, characterized in that: include: Determine the current actual feed water quantity, the current actual fuel quantity, the current actual load and the current target load of the once-through boiler in the current cycle; If it is determined that the current actual water supply, the current actual fuel amount and the current actual load are all normal values ​​and meet the preset water-fuel ratio adaptive control triggering conditions, then determine the backward time period, which is a historical time period of a preset length starting from the current cycle; Based on the current actual feed water amount, the current actual fuel amount, the current actual load, the current target load and the backward time period, calculate the current target feed water amount, the current target fuel amount and the current target water-fuel ratio of the direct current boiler in the current cycle; Based on the current target water supply amount, the current target fuel amount and the current target water-fuel ratio, the current actual water supply amount and the current actual fuel amount are adaptively regulated.

2. The method according to claim 1, characterized in that Determine the backward time period, including: Determining the operating condition type of the once-through boiler in the current cycle; If the operating condition type is a stable operating condition, a historical time period of a first preset time length is reversed from the current cycle to be determined as the reverse time period; If the operating condition type is a variable operating condition, a historical time period of a second preset time length reversed from the current cycle is determined as the reverse time period, wherein the first preset time length is greater than the second preset time length.

3. The method according to claim 1 or 2, characterized in that: Based on the current actual feed water amount, the current actual fuel amount, the current actual load, the current target load and the backward time period, the current target feed water amount, the current target fuel amount and the current target water-fuel ratio of the direct current boiler in the current cycle are calculated, including: Calculate the current target water supply of the direct-flow boiler in the current cycle according to the current actual water supply, the current actual load, the current target load, the backward time period and the water supply control value of the previous cycle; Calculate the current target fuel quantity of the direct-flow boiler in the current cycle according to the current actual fuel quantity, the current actual load, the current target load, the backward time period and the fuel quantity control value of the previous cycle; According to the current actual water supply, the current actual fuel amount, the backward time period and the water-fuel ratio control value of the previous cycle, the current target water-fuel ratio of the direct current boiler in the current cycle is calculated.

4. The method according to claim 3, characterized in that Calculating the current target water supply of the direct-flow boiler in the current cycle according to the current actual water supply, the current actual load, the current target load, the backward time period and the water supply control value of the previous cycle, including: Calculate the historical water consumption value of the once-through boiler in the backward time period according to the backward time period and the water supply control value of the previous cycle; Determine a current water consumption weight value, and calculate a current water consumption value of the direct-flow boiler in a current cycle according to the current actual water supply, the current actual load and the current water consumption weight value; Calculating a current water consumption target value of the once-through boiler in a current cycle according to the historical water consumption value and the current water consumption value; Based on the current water consumption target value and the current target load, the current target water feed volume of the direct current boiler in the current cycle is calculated.

5. The method according to claim 4, characterized in that Determine the current water consumption weight value, including: Determining a change in the calorific value of the fuel of the once-through boiler; The current water consumption weight value is determined according to the fuel calorific value change value, wherein the larger the fuel calorific value change value is, the larger the current water consumption weight value is.

6. The method according to claim 1, characterized in that Based on the current target water supply amount, the current target fuel amount and the current target water-fuel ratio, the current actual water supply amount and the current actual fuel amount are adaptively regulated, including: Based on the midpoint temperature of the once-through boiler in the current cycle, the current target water supply amount, the current target fuel amount and the current target water-fuel ratio are corrected to obtain a current corrected target water supply amount, a current corrected target fuel amount and a current corrected target water-fuel ratio; Based on the current corrected target water supply amount, the current corrected target fuel amount and the current corrected target water-fuel ratio, the current actual water supply amount and the current actual fuel amount are adaptively regulated.

7. The method according to claim 6, characterized in that Based on the current corrected target water supply amount, the current corrected target fuel amount and the current corrected target water-fuel ratio, the current actual water supply amount and the current actual fuel amount are adaptively controlled, including: Calculating a water supply deviation value between the current corrected target water supply and the current actual water supply; calculating a fuel quantity deviation value between the current corrected target fuel quantity and the current actual fuel quantity; Calculating the current actual water-fuel ratio of the direct-flow boiler in the current cycle according to the current actual water supply amount and the current actual fuel amount; The current actual water supply amount is adaptively regulated based on the water supply amount deviation value, and the current actual fuel amount is adaptively regulated based on the fuel amount deviation value, so that the current actual water-fuel ratio is adaptively adjusted to the current corrected target water-fuel ratio.

8. A once-through boiler water-fuel ratio adaptive control device, characterized in that: include: A first determination module is configured to determine a current actual feed water amount, a current actual fuel amount, a current actual load and a current target load of the once-through boiler in a current cycle; The second determination module is configured to determine a backward time period if it is determined that the current actual water supply amount, the current actual fuel amount and the current actual load are all normal values ​​and meet the preset water-fuel ratio adaptive control triggering condition, wherein the backward time period is a historical time period of a preset length starting from the current cycle; A calculation module is configured to calculate the current target feed water amount, the current target fuel amount and the current target water-fuel ratio of the direct current boiler in the current cycle based on the current actual feed water amount, the current actual fuel amount, the current actual load, the current target load and the backward time period; The control module is configured to adaptively control the current actual water supply amount and the current actual fuel amount based on the current target water supply amount, the current target fuel amount and the current target water-fuel ratio.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

Images