Coal-biomass coupling power generation fuel control method and device

Abstract

The application discloses a coal-biomass coupling power generation fuel control method and device, and the method comprises the following steps: obtaining a coal consumption B; the coal consumption B is linearly adjusted into a first feed water flow, the first feed water flow is adjusted by three-order inertia to obtain a first output; a biomass fuel consumption B s is linearly adjusted into a second feed water flow, the second feed water flow is adjusted by three-order inertia and then is adjusted by amplitude limiting to obtain a second output; a separator outlet temperature T in a generator set and a temperature setting value T sp are input into a PID controller to be adjusted by PID to obtain a third output, and the first output to the third output are accumulated to judge whether the minimum feed water flow limit value is exceeded, if the minimum feed water flow limit value is exceeded, the accumulated value is output as a final feed water flow setting value, if the minimum feed water flow limit value is not exceeded, the minimum feed water flow limit value is output as the final feed water flow setting value; the application has the advantages that the problem that the change of the biomass fuel consumption causes the control fluctuation of the main steam pressure is solved.

Description

Technical Field

[0001] This invention relates to the field of thermal power, and more specifically to a method and apparatus for fuel control in coal-biomass coupled power generation. Background Technology

[0002] The low-carbon development of coal-fired power requires reducing coal consumption while generating the same amount of electricity. Currently, partial or complete fuel replacement can be achieved using low-carbon fuels, specifically co-firing biomass fuel with coal. Where possible, the biomass fuel co-firing ratio should be continuously increased until complete biomass fuel replacement is finally achieved. In nature, the amount of agricultural and forestry solid waste generated annually is relatively stable. Utilizing large, high-efficiency coal-fired units to co-fire biomass fuel for power generation is an advanced technology for biomass power generation. This can significantly improve the efficiency of biomass power generation, increase the utilization rate of biomass resources, and significantly reduce the carbon emissions of coal-fired power units. It also increases the flexibility of coal-biomass co-firing power generation, thereby strengthening the sustainability of coal-fired power generation. Supercritical DC unit generators inherently possess characteristics such as pure delay, large inertia, and nonlinearity. Multiple parameters of the unit are interconnected and constrained, exhibiting strong coupling characteristics. Changes in the energy landscape and the increasing demands for grid peak shaving and frequency regulation bring numerous uncertain external disturbances to the unit generators. Furthermore, the co-firing of coal and biomass increases the difficulty of controlling the unit generators. The main control of a supercritical boiler is the most critical link in adjusting steam flow and steam enthalpy. Biomass co-firing places even higher demands on the main control of supercritical boilers. If the main control is not properly managed, in addition to affecting the unit's load regulation capability, it will also cause important parameters such as main steam pressure to exceed limits or fluctuate significantly for a long period of time, affecting the safety of the unit.

[0003] For supercritical once-through (DC) units, the boiler main control primarily includes static fuel composition based on load commands and dynamic feedforward to compensate for heat storage during the initial dynamic load of the DC boiler. Based on this, the boiler main control regulator is designed as a PID controller based on the main steam pressure deviation. Its main function is to eliminate the deviation in steady-state main steam pressure and ensure that the main steam enthalpy and electrical power remain in balance. The boiler dynamic feedforward focuses on advance regulation to compensate for the lag between boiler combustion and turbine work in supercritical units, and cannot achieve quantitative control. In principle, the static fuel quantity and unit load in the boiler main control have a one-to-one correspondence. However, after implementing biomass co-firing, the correspondence between the original coal and the unit load changes. Although biomass co-firing currently uses quantitative co-firing, the input and output of biomass fuel, as well as short-term interruptions due to faults, significantly affect the total fuel quantity entering the furnace, easily causing a mismatch between fuel quantity and load. Main steam pressure control suffers from frequent large fluctuations or long-term large deviations. The paper "Li Yuzhe, Li Nan, Han Ying, et al. Thermodynamic Performance Analysis of Biomass-Coal Coupled Power Generation System [J]. Power Plant System Engineering, 2019, 35(4):1-7." discloses the use of software to analyze the thermodynamic performance of a biomass-coal coupled power generation system and explores the influence of steam integrated parameters on biomass power generation efficiency. However, it does not involve the fuel control method for coal-biomass coupled power generation, and cannot solve the problem of fluctuations in main steam pressure control caused by changes in biomass fuel quantity. Summary of the Invention

[0004] The technical problem to be solved by this invention is that the existing technology lacks a fuel control method for coal-biomass coupled power generation, and cannot solve the problem of fluctuations in main steam pressure control caused by changes in the amount of biomass fuel.

[0005] This invention solves the above-mentioned technical problems through the following technical means: a coal-biomass coupled power generation fuel control method, the method comprising: based on the main steam pressure PT, the unit load command N0, and the biomass fuel quantity B... s The coal consumption B is obtained; the coal consumption B is linearly adjusted to the first water supply flow rate, and the first water supply flow rate is subjected to third-order inertial adjustment to obtain the first output; the biomass fuel consumption B s The second feedwater flow rate is obtained through linear regulation, followed by third-order inertial regulation and then amplitude limiting regulation to obtain the second output; the separator outlet temperature T and the temperature setpoint T in the generator set. sp The input to the PID controller is adjusted by PID to obtain the third output. The sum of the first and third outputs is used to determine whether it exceeds the minimum water supply flow limit. If it does, the sum is used as the final water supply flow setpoint. If it does not exceed, the minimum water supply flow limit is used as the final water supply flow setpoint.

[0006] When biomass fuel is normally delivered to the boiler and co-fired with coal, the amount of biomass fuel B s It can meet a portion of the boiler's combustion rate requirements, at which point the amount of coal fed into the boiler needs to be reduced by a certain proportion. Therefore, this invention is based on the biomass fuel quantity B. s The relationship between the amount of coal burned and the amount of biomass fuel (B) is determined by the main steam pressure (PT), the unit load command (N0), and the amount of biomass fuel (B). s Obtain the amount of coal consumed, B, and then consider the amount of coal consumed, B, and the amount of biomass fuel, B. s The feedwater flow rate is adjusted based on the separator outlet temperature T, taking into full account the biomass fuel quantity B. s The relationship between the amount of biomass fuel and the amount of coal burned (B) is used to determine the amount of coal burned (B). This helps to avoid the significant impact of biomass fuel input, output, and short-term interruptions due to malfunctions on the total amount of fuel fed into the furnace, thereby solving the problem of fluctuations in main steam pressure control caused by changes in the amount of biomass fuel.

[0007] Furthermore, the method based on the main steam pressure PT, unit load command N0, and biomass fuel quantity B... s Obtaining the coal consumption B includes:

[0008] The amount of coal to be burned, B, is obtained using the formula B = B1 + B2 - B3, where,

[0009] B1 = f2(N0), where f2() is a linear function of the unit load command N0;

[0010] B2 = K P2 ·ΔP+∫ΔP·dt+dΔP / dt, K P2 ΔP is the proportionality coefficient, which is the difference between the main steam pressure PT and the pressure setpoint PTSP.

[0011] k is the adjustment coefficient, C S and C B These are the calorific values ​​of biomass fuel and coal, respectively.

[0012] Furthermore, the coal consumption B is linearly adjusted to a first water supply flow rate, including:

[0013] The amount of coal burned, B, is adjusted to the first water supply flow rate by a linear function f3(x), where the input of f3(x) is the amount of coal burned, B, and the output is the first water supply flow rate. The first water supply flow rate decreases as the amount of coal burned, B, increases.

[0014] Furthermore, the step of obtaining the first output by performing third-order inertial regulation on the first water supply flow rate includes:

[0015] The unit load command N0 is adjusted to the basic coal-water time by a linear function f(x), where the input of f(x) is the unit load command N0 and the output is the basic coal-water time. The basic coal-water time decreases as the unit load command N0 increases. The basic coal-water time is multiplied by a correction coefficient to serve as the time parameter for the third-order inertial regulation. The first feedwater flow rate passes through the first inertial link f1(t), the second inertial link f2(t), and the third inertial link f3(t) in sequence to obtain the first output quantity.

[0016] Furthermore, the correction coefficient is selected using the following method:

[0017] When the generator set is in the feedwater RB state, the correction factor A1 is used; when it is not in the feedwater RB state, the correction factor A4 is used. When the generator set is in the primary air RB state, the correction factor A2 is used. When the generator set is in the forced draft and induced draft RB state, the correction factor A3 is used. When the generator set is in the load increase state, the correction factor A5 is used. When the generator set is in the load decrease state, the correction factor A7 is used. Here, RB indicates rapid load reduction in case of auxiliary machine failure.

[0018] Furthermore, the biomass fuel quantity B s The second water supply flow rate is linearly adjusted, including:

[0019] Biomass fuel quantity B s The second water supply flow rate is adjusted by a linear function f5(x), where the input of f5(x) is the biomass fuel quantity B. s The output is the second water supply flow rate, which varies with the amount of biomass fuel B. s The increase leads to a decrease.

[0020] Furthermore, the step of performing third-order inertial regulation followed by amplitude limiting regulation on the second water supply flow rate to obtain the second output includes:

[0021] When biomass fuel is input, constant A8 is used as the time parameter for the third-order inertial regulation of the second feedwater flow rate; when biomass fuel is not input, constant 0 is used as the time parameter for the third-order inertial regulation of the second feedwater flow rate. The third-order inertial regulation includes a first inertial element f4(t), a second inertial element f5(t), and a third inertial element f6(t). After the second feedwater flow rate passes through the third-order inertial regulation, the second output quantity is obtained through the limiting unit.

[0022] Furthermore, the separator outlet temperature T and the temperature setpoint T in the generator set... sp The input to the PID controller is adjusted using PID control to obtain a third output quantity, including:

[0023] The separator outlet temperature T and temperature setpoint T in the generator set spThe PID controller receives the temperature value requiring compensation. Based on the relationship between the temperature value and the feedwater flow rate, the feedwater flow rate compensation value is obtained. The temperature T is higher than the setpoint T. sp In this case, a water supply flow compensation value is added to the original water supply flow rate as a third output value, when the temperature T is lower than the temperature setpoint T. sp In this case, the water flow compensation value is reduced from the original water flow rate as the third output, and PID adjustment is continuously performed until the temperature T equals the temperature setpoint T. sp equal.

[0024] The present invention also provides a coal-biomass coupled power generation fuel control device, the device comprising:

[0025] The coal consumption acquisition module is used to obtain data based on the main steam pressure PT, unit load command N0, and biomass fuel quantity B. s Obtain the amount of coal consumed, B;

[0026] The first water supply flow acquisition module is used to linearly adjust the coal consumption B to the first water supply flow.

[0027] The first output quantity acquisition module is used to obtain the first output quantity by performing third-order inertial adjustment on the first water supply flow rate;

[0028] The second water supply flow acquisition module is used for biomass fuel quantity B. s The flow rate is linearly adjusted to the second water supply flow rate.

[0029] The second output acquisition module is used to perform third-order inertial regulation and then amplitude limiting regulation on the second water supply flow to obtain the second output.

[0030] The third output acquisition module is used to obtain the separator outlet temperature T and the temperature setpoint T in the generator set. sp The third output is obtained by inputting the PID controller and performing PID adjustment.

[0031] The water supply flow rate setpoint acquisition module is used to determine whether the sum of the first output quantity to the third output quantity exceeds the minimum water supply flow rate limit. If it exceeds the limit, the accumulated value is output as the final water supply flow rate setpoint. If it does not exceed the limit, the minimum water supply flow rate limit is output as the final water supply flow rate setpoint.

[0032] Furthermore, the coal consumption acquisition module is also used for:

[0033] The amount of coal to be burned, B, is obtained using the formula B = B1 + B2 - B3, where,

[0034] B1 = f2(N0), where f2() is a linear function of the unit load command N0;

[0035] B2 = K P2·ΔP+∫ΔP·dt+dΔP / dt, K P2 ΔP is the proportionality coefficient, which is the difference between the main steam pressure PT and the pressure setpoint PTSP.

[0036] k is the adjustment coefficient, C S and C B These are the calorific values ​​of biomass fuel and coal, respectively.

[0037] Furthermore, the first water supply flow acquisition module is also used for:

[0038] The amount of coal burned, B, is adjusted to the first water supply flow rate by a linear function f3(x), where the input of f3(x) is the amount of coal burned, B, and the output is the first water supply flow rate. The first water supply flow rate decreases as the amount of coal burned, B, increases.

[0039] Furthermore, the first output acquisition module is also used for:

[0040] The unit load command N0 is adjusted to the basic coal-water time by a linear function f(x), where the input of f(x) is the unit load command N0 and the output is the basic coal-water time. The basic coal-water time decreases as the unit load command N0 increases. The basic coal-water time is multiplied by a correction coefficient to serve as the time parameter for the third-order inertial regulation. The first feedwater flow rate passes through the first inertial link f1(t), the second inertial link f2(t), and the third inertial link f3(t) in sequence to obtain the first output quantity.

[0041] Furthermore, the correction coefficient is selected using the following method:

[0042] When the generator set is in the feedwater RB state, the correction factor A1 is used; when it is not in the feedwater RB state, the correction factor A4 is used. When the generator set is in the primary air RB state, the correction factor A2 is used. When the generator set is in the forced draft and induced draft RB state, the correction factor A3 is used. When the generator set is in the load increase state, the correction factor A5 is used. When the generator set is in the load decrease state, the correction factor A7 is used. Here, RB indicates rapid load reduction in case of auxiliary machine failure.

[0043] Furthermore, the second water supply flow acquisition module is also used for:

[0044] Biomass fuel quantity B s The second water supply flow rate is adjusted by a linear function f5(x), where the input of f5(x) is the biomass fuel quantity B. s The output is the second water supply flow rate, which varies with the amount of biomass fuel B. s The increase leads to a decrease.

[0045] Furthermore, the second output acquisition module is also used for:

[0046] When biomass fuel is input, constant A8 is used as the time parameter for the third-order inertial regulation of the second feedwater flow rate; when biomass fuel is not input, constant 0 is used as the time parameter for the third-order inertial regulation of the second feedwater flow rate. The third-order inertial regulation includes a first inertial element f4(t), a second inertial element f5(t), and a third inertial element f6(t). After the second feedwater flow rate passes through the third-order inertial regulation, the second output quantity is obtained through the limiting unit.

[0047] Furthermore, the third output quantity acquisition module is also used for:

[0048] The separator outlet temperature T and temperature setpoint T in the generator set sp The PID controller receives the temperature value requiring compensation. Based on the relationship between the temperature value and the feedwater flow rate, the feedwater flow rate compensation value is obtained. The temperature T is higher than the setpoint T. sp In this case, a water supply flow compensation value is added to the original water supply flow rate as a third output value, when the temperature T is lower than the temperature setpoint T. sp In this case, the water flow compensation value is reduced from the original water flow rate as the third output, and PID adjustment is continuously performed until the temperature T equals the temperature setpoint T. sp equal.

[0049] The advantage of this invention is that when biomass fuel is normally transported to the boiler and co-fired with coal, the amount of biomass fuel B... s It can meet a portion of the boiler's combustion rate requirements, at which point the amount of coal fed into the boiler needs to be reduced by a certain proportion. Therefore, this invention is based on the biomass fuel quantity B. s The relationship between the amount of coal burned and the amount of biomass fuel (B) is determined by the main steam pressure (PT), the unit load command (N0), and the amount of biomass fuel (B). s Obtain the amount of coal consumed, B, and then consider the amount of coal consumed, B, and the amount of biomass fuel, B. s The feedwater flow rate is adjusted based on the separator outlet temperature T, taking into full account the biomass fuel quantity B. s The relationship between biomass fuel and coal consumption B yields the coal consumption B, which is derived by using the equivalent calorific value substitution method for biomass fuel and coal. If the biomass fuel consumption B... s After the change, the corresponding coal consumption B is calculated according to the ratio of the calorific values ​​of the two fuels, and the coal consumption B is used to compensate for the biomass fuel consumption B. s The change in biomass fuel quantity B will thus solve the problem of biomass fuel quantity B. s This addresses the issue of main steam pressure fluctuations caused by changes, aiming to prevent significant impacts on the total fuel quantity fed into the furnace during biomass fuel input, decommissioning, and short-term interruptions due to malfunctions. Attached Figure Description

[0050] Figure 1This is a schematic diagram of the process of obtaining the amount of coal to be burned in a coal-biomass coupled power generation fuel control method disclosed in Embodiment 1 of the present invention;

[0051] Figure 2 This is a schematic diagram of a coal-biomass coupled power generation fuel control method disclosed in Embodiment 1 of the present invention. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] Example 1

[0054] A method for fuel control in coal-biomass coupled power generation, the method comprising:

[0055] 1) First, based on the main steam pressure PT, unit load command N0, and biomass fuel quantity B... s The main process for obtaining the amount of coal to be burned, B, is as follows:

[0056] like Figure 1 As shown, the amount of coal consumed, B, is obtained using the formula B = B1 + B2 - B3, where,

[0057] B1 = f2(N0), where f2() is a linear function of the unit load command N0;

[0058] B2 = K P2 ·ΔP+∫ΔP·dt+dΔP / dt, K P2 ΔP is the proportionality coefficient, which is the difference between the main steam pressure PT and the pressure setpoint PTSP.

[0059] k is an adjustment coefficient, allowing for manual intervention when the calorific value varies within a small range. C S and C B These are the calorific values ​​of biomass fuel and coal, respectively.

[0060] B1 mainly includes the static coal quantity based on the load command and the dynamic coal quantity based on the change in the load command. B2 is the PID control link based on the main steam pressure deviation. B3 is the fuel feedforward component, which is the amount of coal fed into the furnace calibrated according to the ratio of the calorific value of biomass fuel to that of coal.

[0061] For generator sets adopting a biomass co-firing mode, when biomass fuel is normally delivered to the boiler for co-firing with coal, the amount of biomass fuel B... s If the boiler can meet a portion of its combustion rate requirements, then the amount of coal fed into the boiler needs to be reduced by a certain proportion. The relationship between biomass fuel and coal is represented by f4, which is the ratio of the calorific value per unit of fuel. This relationship is used to adjust the amount of coal (B) during the biomass fuel introduction and withdrawal process to ensure a match between the boiler combustion rate and the unit load, i.e., maintaining a balance between the amount of coal (B) and the amount of biomass fuel (B). s The total calorific value remains stable.

[0062] 2) The coal consumption B is linearly adjusted to the first water supply flow rate, including:

[0063] like Figure 2 As shown, the amount of coal burned, B, is adjusted to the first water supply flow rate by the linear function f3(x), where the input of f3(x) is the amount of coal burned, B, and the output is the first water supply flow rate. The first water supply flow rate decreases as the amount of coal burned, B, increases.

[0064] 3) The method of obtaining the first output quantity by performing third-order inertial regulation on the first water supply flow rate includes:

[0065] Continue reading Figure 2 The unit load command N0 is adjusted to the basic coal-water time by a linear function f(x), where the input of f(x) is the unit load command N0, and the output is the basic coal-water time, which decreases as the unit load command N0 increases. The basic coal-water time is multiplied by a correction coefficient to obtain the time parameter for the third-order inertial regulation. The first feedwater flow rate is obtained after passing through the first inertial link f1(t), the second inertial link f2(t), and the third inertial link f3(t) in sequence. The correction coefficient is selected using the following method:

[0066] When the generator set is in the feedwater RB state, the correction factor A1 is used; when it is not in the feedwater RB state, the correction factor A4 is used. When the generator set is in the primary air RB state, the correction factor A2 is used. When the generator set is in the forced draft and induced draft RB state, the correction factor A3 is used. When the generator set is in the load increase state, the correction factor A5 is used. When the generator set is in the load decrease state, the correction factor A7 is used. Here, RB indicates rapid load reduction in case of auxiliary machine failure.

[0067] 4) The amount of biomass fuel B s The second water supply flow rate is linearly adjusted, including:

[0068] Continue reading Figure 2 Biomass fuel quantity B s The second water supply flow rate is adjusted by a linear function f5(x), where the input of f5(x) is the biomass fuel quantity B. sThe output is the second water supply flow rate, which varies with the amount of biomass fuel B. s The increase leads to a decrease.

[0069] 5) The method of obtaining the second output by performing third-order inertial regulation and then amplitude limiting regulation on the second water supply flow includes:

[0070] Continue reading Figure 2 When biomass fuel is input, constant A8 is used as the time parameter for the third-order inertial regulation of the second feedwater flow rate; when biomass fuel is not input, constant 0 is used as the time parameter for the third-order inertial regulation of the second feedwater flow rate. The third-order inertial regulation includes a first inertial element f4(t), a second inertial element f5(t), and a third inertial element f6(t). After the second feedwater flow rate passes through the third-order inertial regulation, the second output quantity is obtained through the limiting unit.

[0071] 6) The separator outlet temperature T and temperature setpoint T in the generator set sp The input to the PID controller is adjusted using PID control to obtain a third output quantity, including:

[0072] Continue reading Figure 2 The separator outlet temperature T and the temperature setpoint T in the generator set sp The PID controller receives the temperature value requiring compensation. Based on the relationship between the temperature value and the feedwater flow rate, the feedwater flow rate compensation value is obtained. The temperature T is higher than the setpoint T. sp In this case, a water supply flow compensation value is added to the original water supply flow rate as a third output value, when the temperature T is lower than the temperature setpoint T. sp In this case, the water flow compensation value is reduced from the original water flow rate as the third output, and PID adjustment is continuously performed until the temperature T equals the temperature setpoint T. sp equal.

[0073] 7) Continue reading Figure 2 The first to the third output values ​​are summed to determine whether the minimum water supply flow rate limit is exceeded. If it is exceeded, the summed value is used as the final water supply flow rate setting value. If it is not exceeded, the minimum water supply flow rate limit is used as the final water supply flow rate setting value.

[0074] Using the above technical solutions, when biomass fuel is normally transported to the boiler and co-fired with coal, the amount of biomass fuel B... s It can meet a portion of the boiler's combustion rate requirements, at which point the amount of coal fed into the boiler needs to be reduced by a certain proportion. Therefore, this invention is based on the biomass fuel quantity B. s The relationship between the amount of coal burned and the amount of biomass fuel (B) is determined by the main steam pressure (PT), the unit load command (N0), and the amount of biomass fuel (B). sObtain the amount of coal consumed, B, and then consider the amount of coal consumed, B, and the amount of biomass fuel, B. s The feedwater flow rate is adjusted based on the separator outlet temperature T, taking into full account the biomass fuel quantity B. s The relationship between biomass fuel and coal consumption B yields the coal consumption B, which is derived by using the equivalent calorific value substitution method for biomass fuel and coal. If the biomass fuel consumption B... s After the change, the corresponding coal consumption B is calculated according to the ratio of the calorific values ​​of the two fuels, and the coal consumption B is used to compensate for the biomass fuel consumption B. s The change in biomass fuel quantity B will thus solve the problem of biomass fuel quantity B. s This addresses the issue of main steam pressure fluctuations caused by changes, aiming to prevent significant impacts on the total fuel quantity fed into the furnace during biomass fuel input, decommissioning, and short-term interruptions due to malfunctions.

[0075] Example 2

[0076] Based on Embodiment 1, Embodiment 2 of the present invention also provides a coal-biomass coupled power generation fuel control device, the device comprising:

[0077] The coal consumption acquisition module is used to obtain data based on the main steam pressure PT, unit load command N0, and biomass fuel quantity B. s Obtain the amount of coal consumed, B;

[0078] The first water supply flow acquisition module is used to linearly adjust the coal consumption B to the first water supply flow.

[0079] The first output quantity acquisition module is used to obtain the first output quantity by performing third-order inertial adjustment on the first water supply flow rate;

[0080] The second water supply flow acquisition module is used for biomass fuel quantity B. s The flow rate is linearly adjusted to the second water supply flow rate.

[0081] The second output acquisition module is used to perform third-order inertial regulation and then amplitude limiting regulation on the second water supply flow to obtain the second output.

[0082] The third output acquisition module is used to obtain the separator outlet temperature T and the temperature setpoint T in the generator set. sp The third output is obtained by inputting the PID controller and performing PID adjustment.

[0083] The water supply flow rate setpoint acquisition module is used to determine whether the sum of the first output quantity to the third output quantity exceeds the minimum water supply flow rate limit. If it exceeds the limit, the accumulated value is output as the final water supply flow rate setpoint. If it does not exceed the limit, the minimum water supply flow rate limit is output as the final water supply flow rate setpoint.

[0084] Specifically, the coal consumption acquisition module is also used for:

[0085] The amount of coal to be burned, B, is obtained using the formula B = B1 + B2 - B3, where,

[0086] B1 = f2(N0), where f2() is a linear function of the unit load command N0;

[0087] B2 = K P2 ·ΔP+∫ΔP·dt+dΔP / dt, K P2 ΔP is the proportionality coefficient, which is the difference between the main steam pressure PT and the pressure setpoint PTSP.

[0088] k is the adjustment coefficient, C S and C B These are the calorific values ​​of biomass fuel and coal, respectively.

[0089] Specifically, the first water flow acquisition module is also used for:

[0090] The amount of coal burned, B, is adjusted to the first water supply flow rate by a linear function f3(x), where the input of f3(x) is the amount of coal burned, B, and the output is the first water supply flow rate. The first water supply flow rate decreases as the amount of coal burned, B, increases.

[0091] More specifically, the first output acquisition module is also used for:

[0092] The unit load command N0 is adjusted to the basic coal-water time by a linear function f(x), where the input of f(x) is the unit load command N0 and the output is the basic coal-water time. The basic coal-water time decreases as the unit load command N0 increases. The basic coal-water time is multiplied by a correction coefficient to serve as the time parameter for the third-order inertial regulation. The first feedwater flow rate passes through the first inertial link f1(t), the second inertial link f2(t), and the third inertial link f3(t) in sequence to obtain the first output quantity.

[0093] More specifically, the correction factor is selected using the following method:

[0094] When the generator set is in the feedwater RB state, the correction factor A1 is used; when it is not in the feedwater RB state, the correction factor A4 is used. When the generator set is in the primary air RB state, the correction factor A2 is used. When the generator set is in the forced draft and induced draft RB state, the correction factor A3 is used. When the generator set is in the load increase state, the correction factor A5 is used. When the generator set is in the load decrease state, the correction factor A7 is used. Here, RB indicates rapid load reduction in case of auxiliary machine failure.

[0095] Specifically, the second water supply flow acquisition module is also used for:

[0096] Biomass fuel quantity B s The second water supply flow rate is adjusted by a linear function f5(x), where the input of f5(x) is the biomass fuel quantity B.s The output is the second water supply flow rate, which varies with the amount of biomass fuel B. s The increase leads to a decrease.

[0097] More specifically, the second output acquisition module is also used for:

[0098] When biomass fuel is input, constant A8 is used as the time parameter for the third-order inertial regulation of the second feedwater flow rate; when biomass fuel is not input, constant 0 is used as the time parameter for the third-order inertial regulation of the second feedwater flow rate. The third-order inertial regulation includes a first inertial element f4(t), a second inertial element f5(t), and a third inertial element f6(t). After the second feedwater flow rate passes through the third-order inertial regulation, the second output quantity is obtained through the limiting unit.

[0099] Specifically, the third output quantity acquisition module is also used for:

[0100] The separator outlet temperature T and temperature setpoint T in the generator set sp The PID controller receives the temperature value requiring compensation. Based on the relationship between the temperature value and the feedwater flow rate, the feedwater flow rate compensation value is obtained. The temperature T is higher than the setpoint T. sp In this case, a water supply flow compensation value is added to the original water supply flow rate as a third output value, when the temperature T is lower than the temperature setpoint T. sp In this case, the water flow compensation value is reduced from the original water flow rate as the third output, and PID adjustment is continuously performed until the temperature T equals the temperature setpoint T. sp equal.

[0101] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A coal-biomass coupling power generation fuel control method characterized by, The method comprises: obtaining a main steam pressure , a unit load instruction , and a biomass fuel amount ; obtaining a coal combustion amount ; linearly adjusting the coal combustion amount to a first feedwater flow, performing three-order inertia adjustment on the first feedwater flow to obtain a first output; linearly adjusting the biomass fuel amount to a second feedwater flow, performing three-order inertia adjustment and then amplitude limiting adjustment on the second feedwater flow to obtain a second output; inputting a separator outlet temperature in the generator unit and a temperature set value into a PID controller to perform PID adjustment and obtain a third output; and accumulating the first output to the third output to judge whether the accumulated value exceeds a minimum feedwater flow limit value, and if yes, outputting the accumulated value as a final feedwater flow set value, and if not, outputting the minimum feedwater flow limit value as the final feedwater flow set value. The main steam pressure , unit load instruction , and biomass fuel amount Obtain the amount of coal , comprising: By formula Obtaining the amount of coal wherein, , is a linear function of the unit load command ; , is a proportionality factor, is the main steam pressure and the pressure set value the difference; , is an adjustment coefficient, and are the heat values of the biomass fuel and the coal, respectively; The amount of coal burned linearly regulating the first feed water flow to include: Coal consumption Linear function The input of the first adjusting unit is the coal consumption , and the output is the first feedwater flow. The first feedwater flow decreases with the increase of the coal consumption ; and the input of the second adjusting unit is the first feedwater flow , and the output is the second feedwater flow. The second feedwater flow increases with the increase of the first feedwater flow. The biomass fuel amount linearly adjusting the second feed water flow rate, comprising: biomass fuel amount linear function adjusted to the second feed water flow rate, wherein the input is the biomass fuel amount and the output is the second feed water flow rate, the second feed water flow rate decreasing with an increase in the biomass fuel amount ; The temperature at the outlet of the separator in the generator set and the temperature setpoint inputting the PID controller to perform PID regulation to obtain a third output quantity, comprising: Generator set separator outlet temperature and temperature set value The temperature value needed to be compensated is obtained by inputting the PID controller, and the feed water flow compensation value is obtained according to the relationship between the temperature value and the feed water flow, the temperature is higher than the temperature set value , the feed water flow compensation value is added to the original feed water flow as the third output value, the temperature is lower than the temperature set value , the feed water flow compensation value is reduced from the original feed water flow as the third output value, and the PID adjustment is continuously carried out until the temperature is equal to the temperature set value .

2. The coal-biomass coupled power generation fuel control method according to claim 1, wherein The first output quantity is obtained by performing third-order inertia adjustment on the first feed water flow, and the second output quantity is obtained by performing third-order inertia adjustment and amplitude limiting adjustment on the second feed water flow. Unit load command Linear function The basic time of coal water is adjusted, wherein, The input of the unit load command , and the output of the basic time of coal water, the basic time of coal water is shortened with the increase of the unit load command ; the basic time of coal water multiplied by a correction factor is used as a time parameter of the third-order inertia adjustment; the first feed water flow passes through a first inertia link , a second inertia link and a third inertia link in sequence to obtain a first output.

3. The coal-biomass coupled power generation fuel control method according to claim 2, wherein The correction coefficient is selected by using the following method: The correction coefficient A1 is used when the generator set is in the feed water RB state, and the correction coefficient A4 is used when the generator set is not in the feed water RB state; the correction coefficient A2 is used when the generator set is in the primary air RB state; The correction coefficient A3 is used when the generator set is in the induced draft RB state; The correction coefficient A5 is used when the generator set is in the load increase state; The correction coefficient A7 is used when the generator set is in the load decrease state, wherein RB represents the auxiliary machine fault rapid load decrease.

4. The coal-biomass coupled power generation fuel control method according to claim 1, wherein The second output quantity is obtained by performing third-order inertia adjustment and amplitude limiting adjustment on the second feed water flow, and the third output quantity is obtained by performing the third-order inertia adjustment on the third feed water flow. A8 is used as a time parameter of the third-order inertia adjustment of the second feed water flow rate in the case where the biomass fuel is supplied, and 0 is used as a time parameter of the third-order inertia adjustment of the second feed water flow rate in the case where the biomass fuel is not supplied; the third-order inertia adjustment includes a first inertia link , a second inertia link , and a third inertia link , and the second output is obtained from the second feed water flow rate after the second feed water flow rate is sequentially subjected to the third-order inertia adjustment and a limiting unit.

5. A coal-biomass coupling power generation fuel control device characterized by comprising: The device comprises: The coal consumption obtaining module is configured to obtain the coal consumption according to the main steam pressure , the unit load instruction and the biomass fuel consumption ;​ The first feed water flow acquisition module is used for the coal combustion amount The linearly regulated first feed water flow The first output quantity acquisition module is configured to obtain the first output quantity by performing third-order inertia adjustment on the first feed water flow; The second feed water flow rate acquisition module is configured to acquire the biomass fuel amount The second feed water flow rate is linearly adjusted. The second output quantity acquisition module is configured to obtain the second output quantity by performing third-order inertia adjustment and amplitude limiting adjustment on the second feed water flow; A third output quantity acquisition module is configured to acquire a separator outlet temperature in the generator set and a temperature set value The PID controller is input to perform PID adjustment to obtain the third output quantity. The feed water flow set value acquisition module is configured to accumulate the first output quantity to the third output quantity to determine whether the accumulated value exceeds the minimum feed water flow limit value, and if the accumulated value exceeds the minimum feed water flow limit value, the accumulated value is output as the final feed water flow set value, and if the accumulated value does not exceed the minimum feed water flow limit value, the minimum feed water flow limit value is output as the final feed water flow set value; The coal consumption acquisition module is further configured to: By formula Obtaining the amount of coal wherein, , is a linear function of the unit load command ; , is a proportionality factor, is the main steam pressure and the pressure set value the difference; , is an adjustment coefficient, and are the heat values of the biomass fuel and the coal, respectively; The first feed water flow acquisition module is further configured to: Coal consumption Linear function is adjusted to the first feed water flow, wherein The input of the coal consumption , and the output is the first feed water flow, the first feed water flow decreases with the increase of the coal consumption ; The second feed water flow acquisition module is further configured to: biomass fuel amount linear function adjusted to the second feed water flow rate, wherein the input is the biomass fuel amount and the output is the second feed water flow rate, the second feed water flow rate decreasing with an increase in the biomass fuel amount ; The third output quantity acquisition module is further configured to: Separator outlet temperature in generator set and temperature setpoint The PID controller receives the temperature value that needs compensation, and the feedwater flow compensation value is obtained based on the relationship between the temperature value and the feedwater flow rate. Higher than the temperature set value In this case, a water supply flow compensation value is added to the original water supply flow rate as a third output quantity, temperature. Below the temperature set value In this case, the water flow compensation value is reduced from the original water flow rate as the third output, and PID adjustment is continuously performed until the temperature reaches the specified value. With temperature setpoint equal.

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