Adjusting method of variable-speed flue gas baffle and boiler system

Abstract

The invention provides a variable-speed flue gas baffle adjusting method and a boiler system, and belongs to the field of power station boilers. The method comprises the following steps: measuring flue gas temperatures of a front flue and a rear flue in real time through a flue gas measuring device; according to the flue gas temperature of the front flue and the flue gas temperature of the rear flue, the optimal value of the flue gas ratio of the front flue to the flue gas ratio of the rear flue under different load working conditions is measured and calculated; based on the optimal value of the flue gas proportion of the front flue and the rear flue under different load working conditions, the opening degree of the flue gas baffle is adjusted to be the optimal opening degree through the variable-speed adjusting device, so that the power supply coal consumption of the boiler is the lowest. The optimal value of the flue gas proportion of the front flue and the rear flue under different load working conditions is measured and calculated through the flue gas measuring device, the opening degree of the flue gas baffle is adjusted based on the optimal value of the flue gas proportion, and the accuracy of adjusting the opening degree of the flue gas baffle is improved.

Description

Technical Field

[0001] The invention relates to the field of power station boilers, and in particular to an adjustment method for a variable-speed flue gas damper and a boiler system. Background Art

[0002] At present, some boilers are designed with temperature-adjusting flue gas dampers, and the vertical shaft flue is equipped with a horizontal partition wall to divide the vertical shaft flue into front and rear flues. The front flue is equipped with a low-temperature reheater (some boilers also have some main economizers), and the rear flue is equipped with a low-temperature superheater and (part of) economizer. The front and rear flue temperature-adjusting flue gas dampers are arranged at the flue outlet to adjust the ratio of the flue gas volume in the front and rear flues, which is the main means to adjust the reheat steam temperature and reheating cooling water under different load conditions. The adjustment goal is to increase the reheat steam temperature as much as possible (preferably to the rated value) and avoid adding reheating cooling water as much as possible. In the low-load state, the reheat steam temperature is low. By reducing the opening of the flue gas damper on the low-temperature superheater side and increasing the opening of the low-temperature reheater, the reheat steam temperature is increased; if there is reheating cooling water in the high-load state, the opening of the flue gas damper on the low-temperature reheater side is reduced, and the opening of the flue gas damper on the low-temperature superheater side is increased to avoid the use of reheating cooling water. Qualitatively judge the ratio of flue gas volume and flue gas velocity between the front and rear flue according to the opening of the front and rear flue dampers to avoid excessive wear and dust accumulation on the heating surface.

[0003] The opening of the flue gas damper can be adjusted manually or automatically. Manual adjustment not only increases the labor intensity of the operator, but also makes it difficult to adjust in time. The opening of the flue gas damper can also be automatically adjusted by a constant speed actuator. However, constant speed adjustment not only affects the dynamic process adjustment quality of the flue gas damper, but may also cause oscillation of steam temperature (wall temperature) and cooling water, making it difficult to put the automatic adjustment of the flue gas damper into use.

[0004] At present, whether the flue gas damper is adjusted manually or automatically, the dynamic influence of the unit load increase and decrease rate, fuel increase and decrease rate, combustion and flue gas steam-water flow lag and heat transfer thermal resistance on the steam temperature, wall temperature and cooling water is not taken into account. There is a lack of optimization of the timing of the flue gas damper switch action and the switching speed of each damper position based on the dynamic influence law, which leads to hysteresis and oscillation in the steam temperature regulation. Summary of the invention

[0005] In order to solve one of the above technical defects, the present invention provides a method for adjusting a variable speed flue gas damper and a boiler system to achieve automatic adjustment of the opening of the flue gas damper and improve the accuracy of the adjustment of the opening of the flue gas damper.

[0006] A first aspect of the present invention provides a method for adjusting a variable speed flue gas damper, wherein the flue gas damper is installed in a boiler divided flue, the boiler divided flue includes a front flue and a rear flue, a flue gas measuring device is provided in the front flue and the rear flue, and the flue gas damper is connected to a variable speed regulating device, and the method comprises:

[0007] The flue gas temperature of the front flue and the rear flue is measured in real time by a flue gas measuring device;

[0008] According to the flue gas temperature of the front flue and the rear flue, calculate the optimal value of the flue gas ratio between the front flue and the rear flue under different load conditions;

[0009] Based on the optimal value of the flue gas ratio between the front flue and the rear flue under different load conditions, the opening of the flue gas damper is adjusted to the optimal opening through the variable speed regulating device, so that the boiler's power supply coal consumption is minimized.

[0010] In the embodiment of the present invention, the flue gas measuring device comprises a plurality of smoke temperature measuring points, which are respectively arranged in the front flue and the rear flue in front of the smoke damper and the front flue and the rear flue behind the smoke damper.

[0011] In an embodiment of the present invention, the optimal value of the flue gas ratio between the front flue and the rear flue under different load conditions is calculated based on the flue gas temperatures of the front flue and the rear flue, including: calculating the comprehensive impact values ​​of the main steam temperature, reheat steam temperature, superheating water volume, reheating water volume, exhaust temperature and flue gas damper resistance corresponding to different flue gas ratio values ​​between the front flue and the rear flue under different load conditions on the power supply coal consumption, and taking the flue gas ratio value between the front flue and the rear flue with the smallest comprehensive impact value under a certain load condition as the optimal value of the flue gas ratio for that load condition.

[0012] In the embodiment of the present invention, based on the optimal value of the ratio of the flue gas in the front flue and the rear flue under different load conditions, the opening of the flue gas damper is adjusted to the optimal opening by the variable speed regulating device, including:

[0013] The opening of the smoke damper corresponding to the optimal value of the smoke ratio between the front smoke duct and the rear smoke duct under the current load condition is taken as the optimal smoke damper opening value under the load condition;

[0014] According to the optimal smoke damper opening value corresponding to each load condition, the operating parameters of the variable speed regulating device are determined, and the opening of the smoke damper is made to be the optimal opening by adjusting the operating parameters of the variable speed regulating device.

[0015] In the embodiment of the present invention, according to the optimal smoke damper opening value corresponding to each load condition, the operating parameters of the variable speed regulating device are determined, and the opening of the smoke damper is made to be the optimal opening by adjusting the operating parameters of the variable speed regulating device, including:

[0016] The optimal flue gas damper opening value corresponding to each load condition is written into the calculation unit;

[0017] A feedforward signal including the unit load value is obtained through the computing unit, an optimal static opening instruction corresponding to the unit load value is generated according to the optimal flue gas damper opening value and the feedforward signal including the unit load value, and the optimal static opening instruction is output to the variable speed regulating device;

[0018] The speed of the variable speed bidirectional servo motor of the variable speed regulating device and the relationship between the speed ratio of the transmission are adjusted according to the optimal static opening instruction to adjust the opening of the smoke damper to the optimal opening under the current load condition.

[0019] In the embodiment of the present invention, according to the optimal smoke damper opening value corresponding to each load condition, the operating parameters of the variable speed regulating device are determined, and the opening of the smoke damper is made to be the optimal opening by adjusting the operating parameters of the variable speed regulating device, including:

[0020] The optimal flue gas damper opening value corresponding to each load condition is written into the calculation unit;

[0021] The feedforward signal and feedback signal are obtained through the computing unit, wherein the feedforward signal includes the unit load value, the difference between the unit load and the fuel increase / deceleration rate, and the current opening position of the flue gas damper, and the feedback signal includes the change rate and oscillation amplitude of the main steam temperature and the reheat steam temperature, the deviation of the main steam temperature and the reheat steam temperature, the superheating desuperheating water volume, and the reheating desuperheating water volume;

[0022] According to the feedforward signal, the feedback signal and the optimal flue gas damper opening value corresponding to each load condition, an optimal dynamic opening instruction corresponding to a certain load condition to a target load condition is generated, and the optimal dynamic opening instruction is output to the variable speed regulating device;

[0023] The speed of the variable speed bidirectional servo motor of the variable speed regulating device and the relationship between the speed ratio of the transmission are adjusted according to the optimal dynamic opening instruction to adjust the opening of the smoke damper to the optimal opening under the target load condition.

[0024] A second aspect of the present invention provides a boiler system, comprising a boiler divided flue and a flue gas damper installed in the boiler divided flue, wherein the boiler divided flue comprises a front flue and a rear flue, and further comprises a flue gas measuring device and a variable speed regulating device, wherein the flue gas measuring device is arranged in the front flue and the rear flue, and the variable speed regulating device is connected to the flue gas damper;

[0025] The flue gas measuring device is used to measure the flue gas temperature of the front flue and the rear flue in real time, and calculate the optimal value of the flue gas ratio between the front flue and the rear flue under different load conditions according to the flue gas temperature of the front flue and the rear flue;

[0026] The variable speed regulating device is used to adjust the opening of the flue gas damper to the optimal opening based on the optimal value of the flue gas ratio between the front flue and the rear flue under different load conditions, so as to minimize the power supply coal consumption of the boiler.

[0027] In an embodiment of the present invention, the speed-changing adjustment device comprises: a speed-changing bidirectional servo motor, a transmission and a connecting rod mechanism, wherein the speed-changing bidirectional servo motor is connected to the transmission, the transmission is connected to the connecting rod mechanism, and the connecting rod mechanism is connected to the smoke damper.

[0028] In an embodiment of the present invention, the flue gas measuring device comprises: a computing unit;

[0029] The calculation unit is used to write the optimal smoke damper opening value corresponding to each load condition, and the optimal smoke damper opening value is the opening of the smoke damper corresponding to the optimal value of the smoke ratio of the front flue and the rear flue under each load condition;

[0030] The computing unit is used to obtain a feedforward signal and a feedback signal, wherein the feedforward signal includes the unit load value, the difference between the unit load and the fuel increase / deceleration rate, and the current opening position of the flue gas damper, and the feedback signal includes the change rate and oscillation amplitude of the main steam temperature and the reheat steam temperature, the deviation of the main steam temperature and the reheat steam temperature, the superheating desuperheating water volume, and the reheating desuperheating water volume;

[0031] The computing unit generates an optimal dynamic opening instruction corresponding to a certain load condition to a target load condition according to the feedforward signal, the feedback signal and the optimal smoke damper opening value corresponding to each load condition, and outputs the optimal dynamic opening instruction to the variable speed regulating device;

[0032] The speed adjustment device adjusts the speed of the variable speed bidirectional servo motor and the speed ratio of the transmission according to the optimal dynamic opening instruction to adjust the opening of the smoke damper to the optimal opening under the target load condition.

[0033] The above-mentioned variable speed flue gas damper adjustment method and boiler system calculate the optimal value of the flue gas ratio between the front flue and the rear flue under different load conditions according to the flue gas temperatures of the front flue and the rear flue, and adjust the opening of the flue gas damper through a variable speed regulating device based on the optimal value of the flue gas ratio between the front flue and the rear flue under different load conditions, thereby improving the accuracy of the adjustment of the flue gas damper opening, solving the problem of lack of accurate and reliable basis for the adjustment of the flue gas damper opening, and providing a reliable basis for the reasonable and sufficient adjustment of the flue gas damper opening.

[0034] Other features and advantages of the technical solution of the present invention will be described in detail in the specific implementation section below. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0036] Figure 1 is a flow chart of a method for adjusting a variable speed smoke damper provided by an embodiment of the present invention;

[0037] Figure 2 is a schematic structural diagram of a boiler flue provided in an embodiment of the present invention;

[0038] Figure 3 Schematic diagram of the arrangement of the smoke damper provided in an embodiment of the present invention;

[0039] Figure 4 It is a structural block diagram of a variable speed regulating device of a smoke damper provided in an embodiment of the present invention;

[0040] Figure 5 It is a structural block diagram of a boiler system provided by an embodiment of the present invention.

[0041] Description of Reference Numerals

[0042] 1- Horizontal plane of the arrangement of the smoke temperature measuring points in the front flue before the smoke damper,

[0043] 2- Horizontal plane of the arrangement of the flue gas temperature measuring points in the rear flue before the flue gas damper,

[0044] 3- Horizontal plane of the arrangement of the smoke temperature measuring points in the left flue after the smoke damper,

[0045] 4- Horizontal plane of the arrangement of the right flue gas temperature measuring points behind the flue gas damper,

[0046] 5- boiler body, 6- flue gas damper, 7- denitrification device, 8- ammonia injection grid, 9- low temperature reheater,

[0047] 10- low temperature superheater, 11 / 12- main economizer, 13 / 14 / 17 / 18- thermocouples at smoke temperature measuring points,

[0048] 15-front flue in front of the smoke damper, 16-rear flue in front of the smoke damper,

[0049] 19-left flue behind the smoke damper, 20-right flue behind the smoke damper,

[0050] 21-thermal control cabinet, 22-host computer,

[0051] 23-speed adjustment unit, 24-speed bidirectional servo motor, 25-speed transmission, 26-connecting rod mechanism. DETAILED DESCRIPTION

[0052] In order to make the technical solutions and advantages of the embodiments of the present invention more clearly understood, the exemplary embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0053] The embodiment of the present invention provides an optimization method based on flue gas ratio measurement and dynamic and static adjustment of variable speed flue gas dampers. Based on the smoke temperature difference between the front and rear flues before the flue gas damper and the measurement of the smoke temperature before and after the damper, a front and rear flue gas ratio measurement system is established. The flue gas damper variable speed adjustment is realized by frequency conversion (or permanent magnet). On this basis, the static optimal opening and dynamic optimal switching speed of the flue gas damper are clearly defined, and the dynamic and static optimization of the flue gas damper adjustment is realized to ensure the economy, reliability and stability of the flue gas damper adjustment. The flue gas ratio measurement system of the present invention provides an accurate, reliable and economical measurement method for the flue gas ratio of the front and rear flues. The variable speed adjustment of the flue gas damper can improve the linearity of the flue gas damper and achieve the required switching speed. The dynamic and static optimization method of the flue gas damper based on this can ensure that the boiler operates in the most economical state, avoid the oscillation of the adjustment parameters, ensure the automatic input of the flue gas damper, and ensure safety and reliability.

[0054] Figure 1 FIG. 1 is a flow chart of a method for adjusting a variable speed smoke damper provided by an embodiment of the present invention. Figure 1 As shown, the adjustment method of the variable speed smoke damper provided in this embodiment includes the following steps:

[0055] S100, measuring the flue gas temperature of the front flue and the rear flue in real time by means of a flue gas measuring device;

[0056] S200, according to the flue gas temperatures of the front flue and the rear flue, calculate the optimal value of the flue gas ratio between the front flue and the rear flue under different load conditions;

[0057] S300, based on the optimal value of the flue gas ratio between the front flue and the rear flue under different load conditions, adjusts the opening of the flue gas damper to the optimal opening through the variable speed regulating device, so that the boiler's power supply coal consumption is minimized.

[0058] In this embodiment, the flue gas measuring device includes a plurality of smoke temperature measuring points, and the plurality of smoke temperature measuring points are respectively arranged in the front flue and the rear flue in front of the smoke damper and in the front flue and the rear flue behind the smoke damper.

[0059] like Figure 2 and Figure 3As shown, the flue gas in the boiler body 5 flows to the denitrification device 7 through the flue. The flue contains a low-temperature reheater 9, a low-temperature superheater 10, main economizers 11, 12 and a flue gas damper 6. A flue gas temperature measuring plane 1, 2 is arranged in the front flue 15 and the rear flue 16 in front of the flue gas damper 6, and the thermocouples 13, 14 are kept 100mm away from the upper edge of the vertical position of the flue gas damper 6. A flue gas temperature measuring plane 3, 4 is arranged in the left flue 19 and the right flue 20 behind the flue gas damper, and the distance between the flue temperature measuring plane 3, 4 and the ammonia injection grid 8 is 500mm. The flue temperature measuring planes of the front flue 15 and the rear flue 16 in front of the flue gas damper are arranged with three flue temperature measuring point thermocouples 13, 14 according to the simple grid method. The front and rear flues are divided into three equal-area rectangles with a side length a in the width direction, and the flue temperature measuring points are arranged at the intersection of the diagonals of each rectangle. The left flue 19 and the right flue 20 behind the flue gas damper are each arranged with three smoke temperature measuring point thermocouples 17 and 18 according to the simple grid method. The left and right flues are each divided into three rectangles of equal area with a side length of b in the width direction. The smoke temperature measuring points are arranged at the intersection of the diagonals of each rectangle. A wear-resistant stainless steel temperature sleeve is installed horizontally at each smoke temperature measuring point, and the sleeve is fixed to the furnace wall with screws. Thermocouples are used to measure the smoke temperature. The measurement range of the thermocouple meets the local smoke temperature variation range requirements, and the measurement error is no more than ±1%. The thermocouple millivolt signal is connected to the temperature card of the thermal control cabinet 21 by a compensation wire with similar performance to the thermocouple. The temperature card converts the thermocouple millivolt signal into a digital signal through an instrument amplifier and a converter, and transmits it to the host computer 22 through the DPU (controller).

[0060] like Figure 4 As shown, the speed regulating device includes: a speed regulating unit 23, a speed-changing bidirectional servo motor 24, a transmission 25 and a connecting rod mechanism. The speed regulating unit 23 and the speed-changing bidirectional servo motor 24 are used to control the speed-changing bidirectional servo motor 24. The speed-changing bidirectional servo motor 24 is connected to the transmission 25, the transmission 25 is connected to the connecting rod mechanism 26, and the connecting rod mechanism 26 is connected to the smoke damper 6. The speed regulating unit adopts a variable frequency (or permanent magnet) speed regulating device to realize the speed-changing function of the bidirectional servo motor. The bidirectional servo motor drives the transmission, and the driven shaft of the transmission further drives the smoke damper connecting rod actuator, and the smoke damper connecting rod actuator drives the smoke damper to complete the required switching action. The strength of the smoke damper connecting rod actuator meets the speed change requirements, and the smoke damper can adopt any required switching speed within the range of the lowest to the highest load of the unit.

[0061] The speed of the variable-speed bidirectional servo motor and the transmission ratio are designed to meet the maximum and minimum adjustment speed requirements of the smoke damper opening, and should satisfy the following equations:

[0062] § max *n dj *r=n max ;

[0063] § min *n dj *r=n min ;

[0064] Where: n dj is the rated speed of the variable speed bidirectional servo motor, in rpm / min; max ,§ min is the maximum and minimum speed change rate of the inverter, in %; r is the transmission ratio, in decimal;

[0065] n max 、n min The maximum and minimum switching speeds required for the smoke damper correspond to the maximum and minimum output speeds of the output shaft of the transmission, which are rpm / min.

[0066] In the above step S200, the optimal value of the flue gas ratio between the front flue and the rear flue under different load conditions is calculated according to the flue gas temperatures of the front flue and the rear flue measured in real time by the flue gas measuring device. Specifically, the comprehensive impact values ​​of the main steam temperature, reheat steam temperature, superheating water volume, reheating water volume, exhaust temperature and flue gas damper resistance corresponding to different flue gas ratio values ​​between the front flue and the rear flue under different load conditions on the power supply coal consumption are calculated, and the flue gas ratio value between the front flue and the rear flue with the smallest comprehensive impact value under a certain load condition is taken as the optimal value of the flue gas ratio under the load condition.

[0067] Among them, the calculation formula for the influence of main steam temperature on power supply coal consumption corresponding to different flue gas ratio values ​​of the front flue and the rear flue is:

[0068] Δb i zqw =(k i zqw *q cs *10) / (η gl *η gd *29308*(1-C));

[0069] Where Δb i zqw is the impact of the main steam temperature deviation from the rated value on the power supply coal consumption corresponding to the flue gas ratio i of the front flue and the rear flue under the corresponding load condition, in g / kWh;

[0070] k i zqw is the correction coefficient of the main steam temperature to the heat rate of the steam turbine corresponding to the ratio i of the flue gas in the front flue and the rear flue under the corresponding load condition;

[0071] q cs is the heat rate of the steam turbine after correction of the corresponding load condition parameters, η glis the corrected test thermal efficiency of the boiler corresponding to the load condition, η gd is the pipeline efficiency of the unit, and C is the power consumption rate of the unit power plant under the corresponding load condition.

[0072] Similarly, using a method similar to the above calculation method, we can calculate the comprehensive impact of the reheat steam temperature, superheat desuperheating water volume, reheat desuperheating water volume, exhaust temperature and flue gas damper resistance corresponding to different flue gas ratio values ​​of the front flue and the rear flue on the power supply coal consumption.

[0073] For example, the effect of reheat steam temperature on power generation coal consumption can be expressed as:

[0074] Δb i zrw =(k i zrw *q cs *10) / (η gl *η gd *29308*(1-C));

[0075] Where Δb i zrw is the impact of the reheat steam temperature deviation from the rated value on the power supply coal consumption under the corresponding load condition, corresponding to the flue gas ratio i between the front flue and the rear flue, in g / kWh;

[0076] k i zrw The correction coefficient of the heat rate of the steam turbine for the reheat steam temperature corresponding to the ratio of the flue gas in the front and rear flues i to the corresponding load condition is obtained by checking the correction curve of the reheat steam temperature for the heat rate for the corresponding load condition of the flue gas in the front and rear flues i from the rated reheat steam temperature. When the reheat steam temperature is lower than the rated value, a positive value is taken, and when it is higher than the rated value, a negative value is taken, which is %.

[0077] The influence of superheating and desuperheating water volume on power supply coal consumption can be expressed as:

[0078] Δb i gjw =(0.011*G i gjw *G e zq ) / (G zq *(1-C));

[0079] Where Δb i gjw The influence of the superheated desuperheating water volume corresponding to the ratio i of the flue gas in the front and rear flues on the power supply coal consumption corresponding to the load condition is 0 when the desuperheating water comes from the high pressure heater, and positive values ​​when the desuperheating water comes from the outlet of the feed water pump, g / kWh;

[0080] Gi gjw is the amount of superheating and cooling water for the flue gas ratio i of the front and rear flue corresponding to the load condition, t / h;

[0081] G e zq is the main steam volume of the steam turbine under THA condition, t / h;

[0082] G zq is the main steam volume of the turbine corresponding to the load condition, t / h.

[0083] The effect of reheating water volume on power supply coal consumption can be expressed as:

[0084] Δb i zjw =(k i zjw *q cs *10) / (η gl *η gd *29308*(1-C));

[0085] Where Δb i gjw The influence of the reheating and desuperheating water volume corresponding to the ratio i of the flue gas before and after the flue gas on the power supply coal consumption corresponding to the load condition, g / kWh;

[0086] It is the correction coefficient of the heat rate of the steam turbine for the reheating and desuperheating water volume corresponding to the ratio i of the flue gas in the front and rear ducts to the corresponding load condition. The reheating and desuperheating water volume corresponding to the ratio i of the flue gas in the front and rear ducts to the corresponding load condition is checked by the manufacturer's reheating and desuperheating water volume corresponding to the heat rate correction curve, and all of them are positive values.

[0087] The influence of exhaust gas temperature on power supply coal consumption can be expressed as:

[0088] Δb i p y=((0.05~0.06)*(t i py -t e py )*q cs ) / (100*η e gl *η gl *η gd *29308*(1-C));

[0089] Where Δb i py The influence of the exhaust gas temperature corresponding to the ratio i of the flue gas in the front and rear flues on the power supply coal consumption is g / kWh. t i pyis the exhaust gas temperature corresponding to the ratio i of the flue gas in the front and rear flues under the corresponding load condition; t e py is the design exhaust temperature corresponding to the load condition; η e gl is the design boiler efficiency corresponding to the load condition; (0.05~0.06) is the influence coefficient of exhaust gas temperature on boiler efficiency, low-moisture coal takes the lower limit, high-moisture coal takes the upper limit, percentage points / ℃.

[0090] The influence of smoke damper resistance on power supply coal consumption can be expressed as:

[0091] Δb i zl =(Δp i zl *C yf *q cs ) / (100*Δp yf *(1-C) 2 *η gl *η gd *29308);

[0092] Where Δb i zl The influence of the flue gas damper resistance corresponding to the flue gas ratio i on the power supply coal consumption corresponding to the load condition is taken as positive value, g / kWh. Δp i zl is the flue gas damper resistance corresponding to the front and rear flue gas ratio i under the corresponding load condition, kPa. C yf is the power consumption rate of the induced draft fan corresponding to the load condition; Δp yf is the static pressure rise of the induced draft fan corresponding to the load condition, kPa.

[0093] Under each load condition, the comprehensive impact of the parameters of flue gas ratio before and after i on the coal consumption of power supply is:

[0094] ΣΔb i =Δb i zqw +Δb i zrw +Δb i gjw +Δb i zjw +Δb i py +Δp i zl ;

[0095] The comprehensive influence of all parameters of flue gas ratio before and after flue on power supply coal consumption under various load conditions ΣΔb i ,ΣΔb j ,ΣΔb k,ΣΔb l Among them, take the minimum value ΣΔb x min (ΣΔb x min <ΣΔb i ,ΣΔb j ,ΣΔb k ,ΣΔb l ) is the optimal front and rear flue gas ratio for this load condition.

[0096] For each load condition, the optimal front and rear flue smoke damper openings corresponding to the optimal front and rear flue smoke ratios are confirmed as the optimal front and rear flue smoke damper openings for this load condition.

[0097] Optimization of the left and right openings of the flue gas dampers before and after each test load condition: Optimization and adjustment test of the left and right steam temperature (wall temperature) deviation; if there is a large steam temperature deviation (exceeding the manufacturer's allowable value or the wall temperature exceeds the limit) between the main and reheat steam temperatures (wall temperatures) on the left and right sides, or the steam temperature deviation and wall temperature affect the main reheat steam temperature and the amount of super reheating water (first of all, the steam temperature deviation must be reduced by improving the uniformity of the combustion side), then it is necessary to conduct an optimization test on the left and right openings of the flue gas dampers on the deviation side (low reheat and low overheat side). The test tries to ensure that the flue gas ratio of the front and rear flues remains unchanged as much as possible. For conditions with large steam temperature deviation and wall temperature, the damper on the side with lower steam temperature and wall temperature is opened wide, and the damper on the side with higher steam temperature is closed small, and the flue gas resistance on the adjustment side is basically maintained as unchanged as possible. The adjustment target is to improve the steam temperature (wall temperature) deviation and wall temperature overheating and control them in the best state and may not exceed the manufacturer's specified value. At this time, the corresponding left and right flue gas damper openings are the optimal left and right flue gas damper openings.

[0098] The flue gas flow rate is calculated based on the flue gas ratio of the front and rear flue calculated by the flue gas ratio calculation system as follows:

[0099] V qq =xq m / (3600*ρ qq *S qq );

[0100] V qh =yq m / (3600*ρ qh *S qh );

[0101] Among them, V qq V is the flow velocity of the flue before the flue gas damper; qh is the flue gas flow velocity before and after the flue gas baffle; ρ qq is the smoke density in the front flue before the smoke baffle; ρ qh S is the flue gas density before and after the flue gas damper; qqS is the cross-sectional flow area of ​​the flue before the smoke damper; qh It is the cross-sectional flow area of ​​the flue before and after the flue gas damper.

[0102] In the above step S300, the opening of the smoke damper corresponding to the optimal value of the smoke ratio between the front flue and the rear flue under the current load condition is used as the optimal smoke damper opening value for the load condition. According to the optimal smoke damper opening value corresponding to each load condition, the operating parameters of the variable speed regulating device are determined, and the opening of the smoke damper is made to be the optimal opening by adjusting the operating parameters of the variable speed regulating device.

[0103] Specifically, for a certain type of coal and a certain unit load, while ensuring that the heating surface of the vertical flue does not produce abnormal wear and ash accumulation, the left and right main reheat side steam temperature (wall temperature) deviation, the main reheat steam temperature deviation, and the heating surface wall temperature are controlled in the best state and do not exceed the specified value as much as possible, and the minimum flue gas temperature at the inlet of the denitrification device meets the requirements, all parameters affected by the flue gas damper opening (main and reheat steam temperature, overheat and reheat cooling water, exhaust temperature, flue gas resistance) have a comprehensive impact on the power supply coal consumption so that the power supply coal consumption reaches the minimum value for this type of coal and this load condition. The flue gas damper opening at this time is defined as the optimal flue gas damper static opening for this type of coal and this load. The process of seeking the optimal flue gas damper static opening for a certain type of coal under a certain load is called static optimization of the flue gas damper opening.

[0104] In this embodiment, the optimal smoke damper opening value corresponding to each load condition is written into the calculation unit, and the feedforward signal including the unit load value is obtained through the calculation unit. The optimal static opening instruction corresponding to the unit load value is generated according to the optimal smoke damper opening value and the feedforward signal including the unit load value, and the optimal static opening instruction is output to the speed regulating device; the speed regulating device adjusts the relationship between the rotational speed of the variable speed bidirectional servo motor of the speed regulating device and the speed ratio of the transmission according to the optimal static opening instruction, so as to adjust the opening of the smoke damper to the optimal opening under the current load condition, thereby realizing static optimization of the smoke damper opening.

[0105] like Figure 5 As shown, the implementation method of the static optimal opening of the front and rear flue flue flue smoke dampers is: the optimal opening θ of the front and rear flue flue (and left and right sides) smoke dampers corresponding to each load is implanted into the calculation unit. When the unit target load N2 is adjusted in place and the steam temperature (wall temperature) and the cooling water parameters are stable, the unit target load N2 is used as the feedforward signal. After the calculation unit performs comparative calculation, the optimal static opening instruction of the flue gas damper corresponding to the unit load N2 is output to the flue gas damper regulating device. The flue gas damper regulating device adjusts the flue gas damper opening to the optimal static opening under the current load according to the optimal static opening adjustment instruction of the flue gas damper, and the boiler closing parameter is adjusted to the parameter corresponding to the minimum coal consumption of power supply.

[0106] The optimal target of dynamic adjustment of flue gas dampers in front and rear flues is defined as: the process of adjusting the flue gas dampers in front and rear flues from the optimal opening of a certain load N1 to the optimal opening corresponding to the next target load N2 is called dynamic adjustment of flue gas dampers. During the entire dynamic adjustment process, the main and reheat steam temperatures and wall temperatures are in the best state and do not exceed the specified values ​​as much as possible, the main and reheat steam temperatures and wall temperatures change rate does not exceed the specified value, the main and reheat steam temperature deviation does not exceed the specified value (for high and medium pressure combined cylinder units), the main and reheat steam temperature (wall temperature) left and right deviations do not exceed the specified value as much as possible, the main and denitrification device inlet flue gas temperature is not lower than the minimum allowable value, the reheat steam temperature (wall temperature) and cooling water and other related parameters are from the optimal flue gas ratio corresponding parameters of a certain stable load condition to the optimal flue gas ratio corresponding parameters of the target load condition as quickly as possible without abnormal oscillation, the furnace negative pressure is within the normal allowable fluctuation range, and the adjustment process is as economical as possible, then it can be considered that the dynamic adjustment of flue gas dampers has reached the optimal state.

[0107] In this embodiment, the process of adjusting the front and rear flue gas dampers from the optimal opening of a certain load to the optimal opening corresponding to the next target load is called the dynamic adjustment of the flue gas dampers. During the entire dynamic adjustment process, the main and reheat steam temperatures and wall temperatures are in the best state and do not exceed the specified values ​​as much as possible, the main and reheat steam temperatures and wall temperatures change rate does not exceed the specified value, the main and reheat steam temperature deviations do not exceed the specified values ​​as much as possible (for high and medium pressure combined cylinder units), the main and reheat steam temperature (wall temperature) left and right deviations do not exceed the specified values ​​as much as possible, the flue gas temperature at the inlet of the denitrification device is not lower than the minimum allowable value, the reheat steam temperature (wall temperature) and the cooling water and other related parameters reach the corresponding parameters of the optimal flue gas ratio of the target load condition from the corresponding parameters of the optimal flue gas ratio of a certain stable load condition as quickly as possible without abnormal oscillation, the furnace negative pressure is within the normal allowable fluctuation range, and the adjustment process is as economical as possible. It can be considered that the dynamic adjustment of the flue gas damper has reached the optimal state.

[0108] In this embodiment, the optimal flue gas damper opening value corresponding to each load condition is written into the operation unit, and a feedforward signal and a feedback signal are obtained through the operation unit. The feedforward signal includes the unit load value, the difference between the unit load and the fuel increase / deceleration rate, and the current opening position of the flue gas damper. The feedback signal includes the change rate and oscillation amplitude of the main steam temperature and the reheat steam temperature, the deviation of the main steam temperature and the reheat steam temperature, the superheating water volume, and the reheating water volume; according to the feedforward signal, the feedback signal and the optimal flue gas damper opening value corresponding to each load condition, an optimal dynamic opening instruction corresponding to a certain load condition to a target load condition is generated, and the optimal dynamic opening instruction is output to the speed regulating device; according to the optimal dynamic opening instruction, the speed of the variable speed bidirectional servo motor of the speed regulating device and the speed ratio of the transmission are adjusted to adjust the opening of the flue gas damper to the optimal opening under the target load condition, thereby realizing dynamic optimization of the flue gas damper opening.

[0109] Specifically, the optimization method for dynamic adjustment of the opening of the front and rear flue smoke dampers includes: optimization of the dynamic adjustment signal of the smoke damper, test and linearization of the smoke damper characteristics, optimization test of the action timing of the front and rear flue smoke dampers, the rate of change of the smoke ratio and the switching speed of the smoke damper.

[0110] Optimization of dynamic adjustment signal of flue gas damper: main and reheat steam temperature (wall temperature) and superheat and reheat desuperheating water are related to the increase and decrease amplitude and rate of unit load, fuel change rate, combustion and flue gas steam-water flow hysteresis and heating surface heat transfer thermal resistance. Combustion and flue gas steam-water flow hysteresis and heating surface heat storage heat transfer thermal resistance are relatively fixed. The dynamic adjustment of flue gas damper should take the unit (current and target) load, the difference between unit load and fuel increase and decrease rate and flue gas damper opening position as feedforward signal, main and reheat steam temperature (wall temperature) and change rate and oscillation amplitude, main reheat steam temperature deviation, desuperheating water volume as feedback signal, furnace negative pressure fluctuation, denitration device inlet flue gas temperature as restriction conditions, which can improve the adjustment hysteresis and steam temperature (wall temperature) oscillation problems caused by dynamic adjustment of flue gas damper only using steam temperature feedback signal.

[0111] Smoke damper characteristic test and linearization: Smoke damper characteristic test: The unit is under 60% load condition and stabilized for 30 minutes. The low-pass side smoke damper opening is maintained at 50% unchanged, and the low-re-side smoke damper opening is 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20% (the interval can be further reduced if necessary), each stable for 15 minutes, and the low-re-side and low-pass side smoke ratio X is recorded at each opening dz , Y dg , calculate the flue gas ratio change X corresponding to the unit change of the low-side flue gas damper opening dz 100-90 =(X 100 dz -X 90 dz ) / 10, X dz 90-80 =(X 90 dz -X 80 dz ) / 10....X dz 30-20 =(X 30 dz -X 20 dz ) / 10, the smoke ratio on the low over-side changes with the same value but in the opposite direction; then the smoke damper opening on the low re-side remains unchanged at 50%, and the smoke damper opening on the low over-side is respectively at 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20% (the interval can be further reduced if necessary), each stable for 15 minutes, and record the smoke ratios X of the low re-side and low over-side dz , Ydg , calculate the flue gas ratio change X corresponding to the unit change of the low-pass side flue gas damper opening dg 100-90 =(X 100 dg -X 90 dg ) / 10, X dg 90-80 =(X 90 dg -X 80 dg ) / 10....X dg 30-20 =(X 30 dg -X 20 dg ) / 10, the smoke ratio on the low side changes with the same value but in the opposite direction.

[0112] At different smoke damper openings, the smoke ratio changes differently for each unit of opening. The smoke damper opening and smoke ratio are both nonlinear. The nonlinearity of the smoke damper characteristics is one of the main reasons for the hysteresis and oscillation of the adjusted parameters. The nonlinearity of the smoke damper of the fixed speed actuator cannot be changed, but after the variable speed of the smoke damper is realized, the linearity of the smoke ratio change and the smoke damper switch time can be achieved within the entire adjustment range of the smoke damper. For the adjustment of the single-sided smoke damper, if the 50% opening of the lower side is taken as the benchmark, the smoke ratio change within the upper and lower 5% opening range is X dz 55-45 , the time for the smoke damper to switch up and down 5% is t, then the rate of change of the smoke ratio is X dz 55-45 / t, the smoke damper opening speed is 10% / t, taking this smoke ratio change speed as the benchmark, when the initial opening is 100%, if the same smoke ratio change rate is achieved (the smoke ratio is linear with time), the following equation needs to be established: X dz 55-45 / t=X dz 100-x / t, x can be calculated based on the data in the table above, which realizes the linearity between the smoke ratio change and the smoke damper switch time. The corresponding smoke damper switch speed is (100-x) / t (substituting x into the required smoke damper switch speed). Similarly, if the initial opening is 30%, if the same smoke ratio change rate is achieved, the following equation needs to be true: X dz 55-45 / t=X dz 30-x / t, x can be calculated based on the data in the table above, and the smoke damper switching speed is (30-x) / t (substituting x into the required smoke damper switching speed). In other words, after selecting the rate of change of smoke ratio over time, the linearity of smoke ratio change with time can be achieved by adjusting the switching speed of each smoke damper position. The same is true for the low-pass side.

[0113] When the low re- and low over-side smoke dampers are adjusted in the opposite direction at the same time, the required low re- and low over-side smoke ratio change rate X dz+dg / t, when the low-pass side smoke damper opening is A%, and the low-return side smoke damper opening is B%, then X must be satisfied dz+dg / t=ΙX A-x dz / tΙ+ΙX B-y dz / tΙ, and x%+y%≥120%.

[0114] Experiment on optimizing the action timing of flue gas dampers in front and rear flues, the rate of change of flue gas ratio and the switching speed:

[0115] The factors that determine the reasonable switching speed of each flue gas damper opening position are: the rate of change of unit load, the rate of change of fuel, the hysteresis characteristics of combustion and flue gas and steam-water flow and the heat storage heat transfer thermal resistance of the heating surface, the steam temperature (wall temperature) and the cooling water and the rate of change, the damper characteristics of the flue gas damper at different opening positions, etc., which jointly determine the reasonable switching speed of each flue gas damper opening position. Under the condition that the hysteresis characteristics of combustion and flue gas and steam-water flow and the heat storage heat transfer thermal resistance of the heating surface are relatively fixed, the reasonable switching speed of each flue gas damper opening position is mainly related to the rate of change of unit load, the rate of change of fuel, the steam temperature (wall temperature) and the cooling water and the rate of change. The allowable amplitude of furnace negative pressure fluctuation has safety restrictions on the switching speed of the flue gas damper.

[0116] Test conditions: Before the test, the unit is under a certain load condition, the low reheat and low overheat side flue gas damper openings are at the optimal openings under the load condition, and it runs stably for no less than 30 minutes. The main reheat steam temperature, steam pressure, oxygen content, furnace negative pressure and other parameters of the boiler are stable. During the test, the boiler does not discharge sewage, blow soot, or clean coke.

[0117] Optimization of boilers with main economizers on both low recycle and low pass sides: the unit load increases from N1 to N2, and the flue gas damper openings on the low recycle and low pass sides are at the optimal openings A1% and B1% of the load condition before load increase. Initial load increase, the difference between the load increase rate and the fuel increase rate δ NB1 >0, the steam temperature starts to decrease.

[0118] If the reheat steam temperature is lower than the rated value, the main steam temperature reaches the rated value and desuperheating water is added, obtain δ NB1 >0, the first time, with δ NB1As the feedforward signal, increase the opening of the low reheat side flue gas damper, reduce the opening of the low over-side flue gas damper (if the damper opening is at the minimum at this time, maintain the minimum opening unchanged), use the reheat steam temperature and superheated cooling water as feedback signals, maintain the reheat steam temperature unchanged, until the superheated cooling water is reduced to 0t / h, stop the flue gas damper action (if after stopping the flue gas damper action, the main and reheat steam temperatures are lower than the rated value and there is a trend of further reduction, then it is executed according to the situation of "reheat steam temperature is lower than the rated value, and main steam temperature is also lower than the rated value"). During the entire adjustment process, the low reheat flue gas ratio increase rate is selected as X 1 dz+dg / t, X 2 dz+dg / t, ·······, and finally seek the flue gas ratio change rate that can maintain the reheat steam temperature unchanged, the superheat steam temperature at the rated value and the superheated desuperheating water at 0t / h at the fastest speed, which is called the optimal flue gas ratio change rate X of this regulation process 最优 dz+dg / t, the smoke damper opening must satisfy the equation X 最优 dz+dg / t=ΙX A1-E dz / tΙ+ΙX B1-F dg / tΙ, and E%+F%≥120%. The corresponding low re- and low over-side smoke damper switching speeds are (A1-E) / t and (B1-F) / t respectively. This switching speed is called the optimal switching speed for this adjustment process and this damper opening position. Similarly, different δ NB , the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated.

[0119] If the main steam temperature is lower than the rated value, the reheat steam temperature reaches the rated value and reheating water is added, obtain δ NB1 >0 first time, with δ NB1 As the feedforward signal, increase the opening of the low-pass side flue gas damper and reduce the opening of the low-reheat side flue gas damper (if the damper opening is already at the minimum opening, maintain the minimum opening unchanged), take the steam temperature and reheating water as feedback signals, until the reheating water is reduced to 0t / h, and the main steam temperature is higher than the reheating steam temperature, stop the flue gas damper action (the main and reheating steam temperatures are lower than the rated value and there is a trend of further decrease, then it is executed according to the situation of "reheating steam temperature is lower than the rated value, and main steam temperature is also lower than the rated value"). During the whole adjustment process, the increase rate of the low-pass side flue gas ratio is selected as X 1 dz+dg / t, X 2 dz+dg / t, ·······, and finally seek the flue gas ratio change rate that can maintain the reheating water at 0t / h, the main steam temperature is higher than the reheating steam temperature, and the main reheating steam temperature change rate is less than the specified value, which is called the optimal flue gas ratio change rate X of this regulation process.最优 dz+dg / t. The optimal opening of the low re- and low over-side smoke dampers before load change is A1% and B1%, respectively. The smoke damper opening must satisfy the equation X 最优 dz+dg / t=ΙX A1-E dz / tΙ+ΙX B1-F dg / tΙ, and E%+F%≥120%. The corresponding low re- and low over-side smoke damper switch speeds are (A1-E) / t and (B1-F) / t respectively. This switch speed is called the optimal switch speed for this adjustment process and this damper opening position. Similarly, different δ NB , the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated.

[0120] If the reheat steam temperature is lower than the rated value and the main steam temperature is also lower than the rated value, the flue gas damper opening can remain unchanged. However, if the main reheat steam temperature deviation and the steam temperature (wall temperature) change rate exceed the specified value, the steam temperature (wall temperature) is used as the feedback signal to reduce the flue gas ratio on the high steam temperature side (increase the flue gas ratio on the side where the steam temperature reduction rate exceeds the standard), increase the flue gas ratio on the low steam temperature side (reduce the flue gas ratio on the side where the steam temperature reduction rate is low), and control the main reheat steam temperature deviation and the steam temperature (wall temperature) change rate not to exceed the specified value. During the entire adjustment process, the flue gas ratio change rate is selected as X 1 dz+dg / t, X 2 dz+dg / t, ·······, and finally seek the flue gas ratio change rate that can quickly maintain the main reheat steam temperature deviation and the steam temperature (wall temperature) change rate not exceeding the specified value, which is called the optimal flue gas ratio change rate X of this regulation process 最优 dz+dg / t. The optimal opening of the low re- and low over-side smoke dampers before load change is A1% and B1%, respectively. The smoke damper opening must satisfy the equation X 最优 dz+dg / t=ΙX A1-E dz / tΙ+ΙX B1-F dg / tΙ, and E%+F%≥120%. The corresponding low re- and low pass side smoke damper switching speeds are (A1-E) / t and (B1-F) / t respectively. This switching speed is called the optimal switching speed for this adjustment process and this damper opening position. Similarly, different δ NB , the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated.

[0121] If the reheat steam temperature reaches the rated value and reheating water is added, the main steam temperature reaches the rated value and water is added, and the flue gas damper opening remains unchanged. After the superheat (re)heating water is reduced to 0t / h and the superheat (re)heat steam temperature is lower than the rated value, the above three corresponding situations are implemented.

[0122] The difference between the load increase rate and the fuel increase rate δ NB1 =0, the steam temperature remains stable and the flue gas damper opening remains unchanged.

[0123] The difference between the load increase rate and the fuel increase rate δ NB1 When <0, the steam temperature enters the rising process and is connected to δ NB1 <0 feedforward signal at the first time, the low re- and low over-side smoke damper openings begin to adjust from E% and F% to the optimal openings A2% and B2% corresponding to the target load N2 of this adjustment process, and the low re- and low over-side smoke ratio change rates are selected as X 1 dz+dg / t, X 2 dz+dg / t, ·······, in all the flue gas ratio change rates, the ultimate goal is to maintain the feedback signal main reheat steam temperature deviation, steam temperature (wall temperature) change rate within the specified value in the entire adjustment process, the reheating water is 0t / h, the flue gas damper is adjusted in place after the steam temperature (wall temperature) oscillates (see attached Figure 4 The rate of change of the smoke ratio when Φ) < ±2℃ is called the optimal rate of change of the smoke ratio in this regulation process X 最优 dz+dg / t. Then the smoke damper opening must satisfy the equation X 最优 dz+dg / t=ΙX E-A2 dz / tΙ+ΙX F-B2 dg / tΙ. The corresponding low re- and low pass side smoke damper switch speeds are (E-A2) / t and (F-B2) / t respectively. This switch speed is called the optimal switch speed for this adjustment process and this damper opening position. Similarly, different δ NB , the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated. If the flue gas damper is switched in place, the steam temperature (wall temperature) oscillation is difficult to converge quickly. This adjustment process can be divided into two adjustment stages, and the switching speed of the latter stage can be appropriately reduced.

[0124] The unit load is reduced (from N1 to N2), and the low re- and low-pass side flue gas damper openings are at the optimal openings A1% and B1% of the load condition before load increase. Initial load reduction, the difference between the load reduction rate and the fuel reduction rate δ NB1 >0, the steam temperature starts to rise.

[0125] If the reheat steam temperature is lower than the rated value at this time, the main steam temperature reaches the rated value and cooling water is added, and the flue gas damper opening remains unchanged (until the reheat steam temperature reaches the rated value and reheat cooling water appears, it is executed according to the situation of "reheat steam temperature reaches the rated value and reheat cooling water is added, main steam temperature reaches the rated value and cooling water is added"). However, if the reheat steam temperature (wall temperature) change rate exceeds the specified value, the reheat steam temperature (wall temperature) is used as a feedback signal to reduce the low reheat side flue gas ratio and increase the low over-side flue gas ratio, and control the reheat steam temperature (wall temperature) change rate not to exceed the specified value. During the entire adjustment process, the flue gas ratio change rate is selected as X 1 dz+dg / t, X 2 dz+dg / t, ·······, and finally seek the flue gas ratio change rate that can quickly maintain the reheat steam temperature (wall temperature) change rate not exceeding the specified value, which is called the optimal flue gas ratio change rate X of this regulation process 最优 dz+dg / t. The optimal opening of the low re- and low over-side smoke dampers before load change is A1% and B1%, respectively. The smoke damper opening must satisfy the equation X 最优 dz+dg / t=ΙX A1-E dz / tΙ+ΙX B1-F dg / tΙ, and E%+F%≥120%. The corresponding low re- and low over-side smoke damper switching speeds are (A1-E) / t and (B1-F) / t respectively. This switching speed is called the optimal switching speed for this adjustment process and this damper opening position. Similarly, different δ NB , the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated.

[0126] If the main steam temperature is lower than the rated value, the reheat steam temperature reaches the rated value and reheating water is added, obtain δ NB1 >0 first time, with δ NB1 The feedforward signal is used, and the steam temperature and reheating water are used as feedback signals to automatically increase the low-pass side flue gas damper opening and reduce the low-reheat side flue gas damper opening (if the damper opening is already at the minimum opening, maintain the minimum opening unchanged). When the reheating water is reduced to 0t / h and the main steam temperature is higher than the reheating steam temperature, the flue gas damper action is stopped. During the entire adjustment process, the flue gas ratio change rate is selected as X 1 dz+dg / t, X 2 dz+dg / t, ·······, and finally seek the flue gas ratio change rate that can maintain the reheating water at 0t / h, the main steam temperature is higher than the reheating steam temperature, and the steam temperature (wall temperature) change rate does not exceed the specified value, which is called the optimal flue gas ratio change rate X of this regulation process 最优 dz+dg / t. The optimal opening of the low re- and low over-side smoke dampers before load change is A1% and B1%, respectively. The smoke damper opening must satisfy the equation X 最优 dz+dg / t=ΙX A1-E dz / tΙ+ΙX B1-F dg / tΙ, and E%+F%≥120%. The corresponding low re- and low over-side smoke damper switching speeds are (A1-E) / t and (B1-F) / t respectively. This switching speed is called the optimal switching speed for this adjustment process and this damper opening position. Similarly, different δ NB , the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated.

[0127] If the reheat steam temperature is lower than the rated value and the main steam temperature is also lower than the rated value, the flue gas damper opening remains unchanged until the main (re)heat steam temperature reaches the rated value and superheating (re)heating water appears, and the corresponding situation is executed. However, if the main reheat steam temperature deviation and the steam temperature (wall temperature) change rate exceed the specified value, the steam temperature (wall temperature) is used as the feedback signal to reduce the flue gas ratio on the high steam temperature side (increase the flue gas ratio on the side where the steam temperature reduction rate exceeds the standard), increase the flue gas ratio on the low steam temperature side (reduce the flue gas ratio on the side where the steam temperature reduction rate is low), and control the main reheat steam temperature deviation and the steam temperature (wall temperature) change rate not to exceed the specified value. During the entire adjustment process, the flue gas ratio change rate is selected as X 1 dz+dg / t, X 2 dz+dg / t, ·······, and finally seek the flue gas ratio change rate that can quickly maintain the main reheat steam temperature deviation and the steam temperature (wall temperature) change rate not exceeding the specified value, which is called the optimal flue gas ratio change rate X of this regulation process 最优 dz+dg / t. The optimal opening of the low re- and low over-side smoke dampers before load change is A1% and B1%, respectively. The smoke damper opening must satisfy the equation X 最优 dz+dg / t=ΙX A1-E dz / tΙ+ΙX B1-F dg / tΙ, and E%+F%≥120%. The corresponding low re- and low pass side smoke damper switching speeds are (A1-E) / t and (B1-F) / t respectively. This switching speed is called the optimal switching speed for this adjustment process and this damper opening position. Similarly, different δ NB , the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated.

[0128] If the reheat steam temperature reaches the rated value and reheating water is added, the main steam temperature reaches the rated value and desuperheating water is added, then δNB1 >0 first time, with δ NB1 As the feedforward signal, steam temperature and reheating water are used as feedback signals to reduce the low re-side flue gas damper opening, increase the low over-gas damper opening, maintain the reheating water at 0t / h, and the reheating steam temperature at the rated value. 1 dz+dg / t, X 2 dz+dg / t, ·······, and finally seek the flue gas ratio change rate that can quickly maintain the reheating water at 0t / h and the reheating steam temperature at the rated value, which is called the optimal flue gas ratio change rate X of this regulation process. 最优 dz+dg / t. The optimal opening of the low re- and low over-side smoke dampers before load change is A1% and B1%, respectively. The smoke damper opening must satisfy the equation X 最优 dz+dg / t=ΙX A1-E dz / tΙ+ΙX B1-F dg / tΙ, and E%+F%≥120%. The corresponding low re- and low over-side smoke damper switching speeds are (A1-E) / t and (B1-F) / t respectively. This switching speed is called the optimal switching speed for this adjustment process and this damper opening position. Similarly, different δ NB , the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated.

[0129] The difference between the load reduction rate and the fuel reduction rate δ NB1 =0, the steam temperature remains stable, the smoke damper stops moving and remains stationary.

[0130] The difference between the load reduction rate and the fuel reduction rate δ NB1 <0. Steam temperature and cooling water enter the descending process and receive δ NB1 <0 feedforward signal, the low re- and low over-side smoke damper openings start to adjust from E% and F% to the optimal openings A2% and B2% corresponding to the target load N2 of this adjustment process, and the low re- and low over-side smoke ratio change rates are selected as X 1 dz+dg / t, X 2 dz+dg / t, ·······, among all the flue gas ratio change rates, the one that can maintain the feedback signal main and reheat steam temperature (wall temperature) change rate and deviation within the specified value in the entire adjustment process, and the flue gas ratio change rate with the steam temperature (wall temperature) oscillation <±2℃ after the flue gas damper is adjusted in place is finally sought. This is called the optimal flue gas ratio change rate X of this adjustment process. 最优 dz+dg / t. Then the smoke damper opening must satisfy the equation X最优 dz+dg / t=ΙX E-A2 dz / tΙ+ΙX F-B2 dg / tΙ. The corresponding low re- and low pass side smoke damper switch speeds are (E-A2) / t and (F-B2) / t respectively. This switch speed is called the optimal switch speed for this adjustment process and this damper opening position. Similarly, different δ NB , the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated. If the flue gas damper is switched in place, the steam temperature (wall temperature) oscillation is difficult to converge quickly. This adjustment process can be divided into two adjustment stages, and the switching speed of the latter stage can be appropriately reduced.

[0131] For boilers with only main economizers on the low-pass side. When the unit load increases (from N1 to N2), the flue gas damper openings on the low-recycle and low-pass sides are at the optimal openings A1% and B1% of the load condition before load increase. Initial load increase, the difference between the load increase rate and the fuel increase rate δ NB1 >0, the steam temperature starts to decrease.

[0132] If the reheat steam temperature is lower than the rated value at this time, the main steam temperature reaches the rated value and the cooling water is added, the flue gas damper opening remains unchanged (if the main steam temperature is also lower than the rated value, it will be executed according to the situation of "reheat steam temperature is lower than the rated value, main steam temperature is lower than the rated value"). However, if the main reheat steam temperature deviation and the steam temperature (wall temperature) change rate exceed the specified value, the steam temperature (wall temperature) is used as the feedback signal to reduce the flue gas proportion on the high steam temperature side (increase the flue gas proportion on the side where the steam temperature drop rate exceeds the standard), and increase the flue gas proportion on the low steam temperature side (reduce the flue gas proportion on the side where the steam temperature drop rate is low). Control the main reheat steam temperature deviation and the steam temperature (wall temperature) change rate not to exceed the specified value. During the entire adjustment process, the flue gas proportion change rate is selected as X 1 dz+dg / t, X 2 dz+dg / t, ·······, and finally seek the flue gas ratio change rate that can quickly maintain the main reheat steam temperature deviation and the steam temperature (wall temperature) change rate not exceeding the specified value, which is called the optimal flue gas ratio change rate X of this regulation process 最优 dz+dg / t. The optimal opening of the low re- and low over-side smoke dampers before load change is A1% and B1%, respectively. The smoke damper opening must satisfy the equation X 最优 dz+dg / t=ΙX A1-E dz / tΙ+ΙX B1-F dg / tΙ, and E%+F%≥120%. The corresponding low re- and low over-side smoke damper switching speeds are (A1-E) / t and (B1-F) / t respectively. This switching speed is called the optimal switching speed for this adjustment process and this damper opening position. Similarly, different δ NB , the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated.

[0133] If the main steam temperature is lower than the rated value, the reheat steam temperature reaches the rated value and reheating water is added, obtain δ NB1 >0 first time, with δ NB1 As the feedforward signal, the steam temperature and reheating water are used as feedback signals to reduce the opening of the flue gas damper on the low reheat side and increase the opening of the flue gas damper on the low overheat side until the reheating water is reduced to 0t / h and the main steam temperature is greater than the reheating steam temperature, and the flue gas damper action is stopped (if the main and reheating steam temperatures are lower than the rated values ​​and have a trend of further decrease, the "reheating steam temperature is lower than the rated value, and the main steam temperature is also lower than the rated value" situation is executed). However, if the steam temperature (wall temperature) change rate exceeds the specified value, the steam temperature (wall temperature) is used as the feedback signal to increase the flue gas proportion on the side where the steam temperature drop rate exceeds the standard, and reduce the flue gas proportion on the side where the steam temperature drop rate is low, so as to control the steam temperature (wall temperature) change rate not to exceed the specified value. During the entire adjustment process, the increase rate of the low overheat side flue gas proportion is selected as X 1 dz+dg / t, X 2 dz+dg / t, ·······, and finally seek the flue gas ratio change rate that can quickly maintain the reheating water at 0t / h, the main steam temperature greater than the reheating steam temperature and the main steam temperature, and the steam temperature (wall temperature) change rate does not exceed the specified value, which is called the optimal flue gas ratio change rate X of this regulation process. 最优 dz+dg / t. The optimal opening of the low re- and low over-side smoke dampers before load change is A1% and B1%, respectively. The smoke damper opening must satisfy the equation X 最优 dz+dg / t=ΙX A1-E dz / tΙ+ΙX B1-F dg / tΙ, and E%+F%≥120%. The corresponding low re- and low over-side smoke damper switching speeds are (A1-E) / t and (B1-F) / t respectively. This switching speed is called the optimal switching speed for this adjustment process and this damper opening position. Similarly, different δ NB , the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated.

[0134] If the reheat steam temperature is lower than the rated value, the main steam temperature is also lower than the rated value. If the main steam temperature is higher than the reheat steam temperature, the flue gas damper opening remains unchanged. If the main steam temperature is lower than the reheat steam temperature, obtain δ NB1>0 first time, with δ NB1 As the feedforward signal, the steam temperature is used as the feedback signal to reduce the opening of the low reheat side flue gas damper and increase the opening of the low overheat side flue gas damper until the main steam temperature is higher than the reheat steam temperature, and the flue gas damper action is stopped. However, if the main reheat steam temperature deviation and the steam temperature (wall temperature) change rate exceed the specified value, the steam temperature (wall temperature) is used as the feedback signal to reduce the flue gas proportion on the high steam temperature side (increase the flue gas proportion on the side where the steam temperature decrease rate exceeds the standard), increase the flue gas proportion on the low steam temperature side (reduce the flue gas proportion on the side where the steam temperature decrease rate is low), and control the main reheat steam temperature deviation and the steam temperature (wall temperature) change rate not to exceed the specified value. During the entire adjustment process, the flue gas proportion increase rate is selected as X 1 dz+dg / t, X 2 dz+dg / t, ·······, and finally seek the flue gas ratio change rate that can quickly maintain the main steam temperature greater than the reheat steam temperature, the main reheat steam temperature deviation, and the steam temperature (wall temperature) change rate not exceeding the specified value, which is called the optimal flue gas ratio change rate X of this regulation process 最优 dz+dg / t. The optimal opening of the low re- and low over-side smoke dampers before load change is A1% and B1%, respectively. The smoke damper opening must satisfy the equation X 最优 dz+dg / t=ΙX A1-E dz / tΙ+ΙX B1-F dg / tΙ, and E%+F%≥120%. The corresponding low re- and low over-side smoke damper switching speeds are (A1-E) / t and (B1-F) / t respectively. This switching speed is called the optimal switching speed for this adjustment process and this damper opening position. Similarly, different δ NB , the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated.

[0135] If the reheat steam temperature reaches the rated value and reheating water is added, the main steam temperature reaches the rated value and desuperheating water is added, then δ NB1 >0 first time, with δ NB1 The feedforward signal is used, and the steam temperature and reheating water are used as feedback signals. The low reheating flue gas damper opening is automatically reduced, the low over-side flue gas damper opening is increased, the reheating water is reduced to 0t / h, and the flue gas damper action is stopped (when "the reheating steam temperature is lower than the rated value, the main steam temperature is equal to the rated value and the cooling water is added" or "the reheating steam temperature is lower than the rated value, and the main steam temperature is lower than the rated value", the above-mentioned related clauses shall be followed). During the entire adjustment process, the flue gas ratio change rate is selected as X 1 dz+dg / t, X 2 dz+dg / t, ·······, and finally seek the flue gas ratio change rate that can quickly maintain the reheating and desuperheating water to 0t / h, which is called the optimal flue gas ratio change rate X of this regulation process. 最优 dz+dg / t. The optimal opening of the low re- and low over-side smoke dampers before load change is A1% and B1%, respectively. The smoke damper opening must satisfy the equation X 最优 dz+dg / t=ΙX A1-E dz / tΙ+ΙX B1-F dg / tΙ, and E%+F%≥120%. The corresponding low re- and low over-side smoke damper switching speeds are (A1-E) / t and (B1-F) / t respectively. This switching speed is called the optimal switching speed for this adjustment process and this damper opening position. Similarly, different δ NB , the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated.

[0136] The difference between the load growth rate and the fuel growth rate δ NB1 =0, the steam temperature remains stable and the smoke damper remains stationary.

[0137] Load growth rate and fuel growth rate δ NB1 <0, steam temperature and cooling water enter the rising process, connected to δ NB1 <0 feedforward signal, the low re- and low over-side smoke damper openings start to adjust from E% and F% to the optimal openings A2% and B2% corresponding to the target load N2 of this adjustment process, and the low re- and low over-side smoke ratio change rates are selected as X 1 dz+dg / t, X 2 dz+dg / t, ·······, among all the flue gas ratio change rates, we finally seek the flue gas ratio change rate that can maintain the feedback signal main and reheat steam temperature (wall temperature) change rate and deviation within the specified value during the entire adjustment process, the reheating water is 0t / h, and the steam temperature (wall temperature) oscillation is less than ±2℃ after the flue gas damper is adjusted in place. This is called the optimal flue gas ratio change rate X of this adjustment process. 最优 dz+dg / t. Then the smoke damper opening must satisfy the equation X 最优 dz+dg / t=ΙX E-A2 dz / tΙ+ΙX F-B2 dg / tΙ. The corresponding low re- and low over-side smoke damper switch speeds are (E-A2) / t and (F-B2) / t respectively. This switch speed is called the optimal switch speed for this adjustment process and this damper opening position. Similarly, different δ NB, the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated. If the flue gas damper is switched in place, the steam temperature (wall temperature) oscillation is difficult to converge quickly. This adjustment process can be divided into two adjustment stages, and the switching speed of the latter stage can be appropriately reduced.

[0138] When the unit is reducing load (from N1 to N2), the opening of the flue gas damper on the low refueling and low overfueling sides is at the optimal opening before the load is increased, A1% and B1%. Initial load reduction, the difference between the load reduction rate and the fuel reduction rate δ NB1 >0, the steam temperature starts to rise.

[0139] If the reheat steam temperature is lower than the rated value at this time, the main steam temperature reaches the rated value and cooling water is added, and the flue gas damper opening remains unchanged (until the reheat steam temperature reaches the rated value and cooling water is added, it is executed according to the situation of "reheat steam temperature reaches the rated value and reheat cooling water is added, main steam temperature reaches the rated value and cooling water is added"). However, if the steam temperature (wall temperature) change rate exceeds the specified value, the steam temperature (wall temperature) is used as the feedback signal to reduce the flue gas proportion on the side where the steam temperature rise rate exceeds the standard, increase the flue gas proportion on the side with a low steam temperature rise rate, and control the steam temperature (wall temperature) change rate not to exceed the specified value. During the entire adjustment process, the flue gas proportion change rate is selected as X 1 dz+dg / t, X 2 dz+dg / t, ·······, and finally seek the flue gas ratio change rate that can keep the steam temperature (wall temperature) change rate within the specified value as quickly as possible, which is called the optimal flue gas ratio change rate X of this regulation process. 最优 dz+dg / t. The optimal opening of the low re- and low over-side smoke dampers before load change is A1% and B1%, respectively. The smoke damper opening must satisfy the equation X 最优 dz+dg / t=ΙX A1-E dz / tΙ+ΙX B1-F dg / tΙ, and E%+F%≥120%. The corresponding low re- and low over-side smoke damper switching speeds are (A1-E) / t and (B1-F) / t respectively. This switching speed is called the optimal switching speed for this adjustment process and this damper opening position. Similarly, different δ NB , the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated.

[0140] If the main steam temperature is lower than the rated value at this time, the reheat steam temperature reaches the rated value and reheating water is added, then the temperature is connected to δ NB1 >0 first time, with δ NB1The feedforward signal is used, and the steam temperature (wall temperature) and reheating water are used as feedback signals. The low reheat side flue gas damper opening is reduced, and the low overheat side flue gas damper opening is increased until the reheating water is reduced to 0t / h, and the main steam temperature is higher than the reheating steam temperature, the flue gas damper action is stopped, and the steam temperature (wall temperature) change rate is controlled not to exceed the specified value (until the main steam temperature reaches the rated value and overheating water is added, according to "reheating steam temperature is lower than the rated value, main steam temperature reaches the rated value and overheating water is added" or "main steam temperature reaches the rated value and overheating water is added, reheating steam temperature reaches the rated value and reheating water is added"). During the entire adjustment process, the flue gas ratio change rate is selected as X 1 dz+dg / t, X 2 dz+dg / t, ·······, and finally seek the flue gas ratio change rate that can quickly maintain the reheating water reduction to 0t / h, with the main steam temperature higher than the reheating steam temperature and the steam temperature (wall temperature) change rate not exceeding the specified value, which is called the optimal flue gas ratio change rate X of this regulation process 最优 dz+dg / t. The optimal opening of the low re- and low over-side smoke dampers before load change is A1% and B1%, respectively. The smoke damper opening must satisfy the equation X 最优 dz+dg / t=ΙX A1-E dz / tΙ+ΙX B1-F dg / tΙ, and E%+F%≥120%. The corresponding low re- and low over-side smoke damper switching speeds are (A1-E) / t and (B1-F) / t respectively. This switching speed is called the optimal switching speed for this adjustment process and this damper opening position. Similarly, different δ NB , the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated.

[0141] If the reheat steam temperature is lower than the rated value, the main steam temperature is also lower than the rated value. If the main steam temperature is higher than the reheat steam temperature, the flue gas damper opening remains unchanged. If the main steam temperature is lower than the reheat steam temperature, the flue gas damper opening remains unchanged. NB1 >0 first time, with δ NB1 The main steam temperature is used as the feedforward signal, and the steam temperature (wall temperature) is used as the feedback signal to reduce the opening of the low reheat side flue gas damper and increase the opening of the low overheat side flue gas damper until the main steam temperature is greater than the reheat steam temperature, and the flue gas damper action is stopped (if the overheat and reheat steam temperatures reach the rated values ​​and desuperheating water is added, it is executed according to the relevant situation). However, if the main reheat steam temperature deviation and the steam temperature (wall temperature) change rate exceed the specified value, the steam temperature (wall temperature) is used as the feedback signal to reduce the flue gas proportion on the high steam temperature side (reduce the flue gas proportion on the side where the steam temperature rise rate exceeds the standard), increase the flue gas proportion on the low steam temperature side (increase the flue gas proportion on the side where the steam temperature rise rate is low), and control the main reheat steam temperature deviation and the steam temperature (wall temperature) change rate not to exceed the specified value. During the entire adjustment process, the flue gas proportion change rate is selected as X1 dz+dg / t, X 2 dz+dg / t, ·······, and finally seek the flue gas ratio change rate that can quickly maintain the main steam temperature greater than the reheat steam temperature, the main reheat steam temperature deviation, and the steam temperature (wall temperature) change rate not exceeding the specified value, which is called the optimal flue gas ratio change rate X of this regulation process 最优 dz+dg / t. The optimal opening of the low re- and low over-side smoke dampers before load change is A1% and B1%, respectively. The smoke damper opening must satisfy the equation X 最优 dz+dg / t=ΙX A1-E dz / tΙ+ΙX B1-F dg / tΙ, and E%+F%≥120%. The corresponding low re- and low over-side smoke damper switching speeds are (A1-E) / t and (B1-F) / t respectively. This switching speed is called the optimal switching speed for this adjustment process and this damper opening position. Similarly, different δ NB , the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated.

[0142] If the reheat steam temperature reaches the rated value and reheating water is added, the main steam temperature reaches the rated value and desuperheating water is added, then the NB1 >0 first time, with δ NB1 As the feedforward signal, the steam temperature (wall temperature) and reheating water are used as feedback signals to reduce the low re-side flue gas damper opening, increase the low over-gas damper opening, maintain the reheating water at 0t / h, and the reheating steam temperature at the rated value. During the entire regulation process, the flue gas ratio change rate is selected as X 1 dz+dg / t, X 2 dz+dg / t, ·······, and finally seek the flue gas ratio change rate that can quickly maintain the reheating water reduction to 0t / h and the reheating steam temperature to reach the rated value, which is called the optimal flue gas ratio change rate X of this regulation process. 最优 dz+dg / t. The optimal opening of the low re- and low over-side smoke dampers before load change is A1% and B1%, respectively. The smoke damper opening must satisfy the equation X 最优 dz+dg / t=ΙX A1-E dz / tΙ+ΙX B1-F dg / tΙ, and E%+F%≥120%. The corresponding low re- and low over-side smoke damper switch speeds are (A1-E) / t and (B1-F) / t respectively. This switch speed is called the optimal switch speed for this adjustment process and this damper opening position. Similarly, different δNB , the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated.

[0143] The difference between the load reduction rate and the fuel reduction rate δ NB1 =0, the steam temperature remains stable, the smoke damper stops moving and remains stationary.

[0144] The difference between the load reduction rate and the fuel reduction rate δ NB <0, steam temperature and cooling water enter the descending process, and then NB1 <0 feedforward signal, the low re- and low over-side smoke damper openings start to adjust from E% and F% to the optimal openings A2% and B2% corresponding to the target load N2 of this adjustment process, and the low re- and low over-side smoke ratio change rates are selected as X 1 dz+dg / t, X 2 dz+dg / t, ·······, among all the flue gas ratio change rates, the one that can maintain the feedback signal main and reheat steam temperature (wall temperature) change rate and deviation within the specified value in the entire adjustment process, and the flue gas ratio change rate with the steam temperature (wall temperature) oscillation <±2℃ after the flue gas damper is adjusted in place is finally sought. This is called the optimal flue gas ratio change rate X of this adjustment process. 最优 dz+dg / t. Then the smoke damper opening must satisfy the equation X 最优 dz+dg / t=ΙX E-A2 dz / tΙ+ΙX F-B2 dg / tΙ. The corresponding low re- and low over-side smoke damper switch speeds are (E-A2) / t and (F-B2) / t respectively. This switch speed is called the optimal switch speed for this adjustment process and this damper opening position. Similarly, different δ NB , the corresponding optimal flue gas ratio change rate and the corresponding optimal flue gas damper switching speed can be calculated. If the flue gas damper is switched in place, the steam temperature (wall temperature) oscillation is difficult to converge quickly. This adjustment process can be divided into two adjustment stages, and the switching speed of the latter stage can be appropriately reduced.

[0145] Implementation of the optimal action timing and switching speed of the flue gas dampers in the front and rear flues: The optimal switching speed of the flue gas dampers obtained from the experiments under the above-mentioned conditions is implanted into the calculation unit. For the dynamic process of a unit load N1 changing to a unit target load N2, the difference between the unit load change rate and the pulverizing system fuel change rate, the optimal flue gas damper opening A1, B1 corresponding to the N1 load is used as the feedforward signal, and the main reheat steam temperature and super reheating desuperheating water volume are used as the feedback signal. Through the comparison and other calculations of the calculation unit, the optimal switching speed and action timing of the flue gas damper obtained from the experiments under each condition are selected, and the switching speed and action timing instructions are sent to the flue gas damper adjustment device to adjust the boiler. The relevant parameters in the adjustment process are controlled to the optimized state. After reaching the unit load N2, the flue gas damper opening reaches the optimal opening A2, B2 corresponding to the unit load N2, and the relevant parameters are controlled at the optimal value under the N2 load. During the adjustment process, the steam temperature (wall temperature), the rate of change of steam temperature (wall temperature), the steam temperature deviation, the furnace negative pressure, the steam temperature (wall temperature) oscillation, the flue gas temperature at the inlet of the denitrification device, etc. are fed back to the calculation unit, and the calculation unit performs comparative calculations. If the specified value is exceeded, the calculation unit sends a reverse fine-tuning command to the flue gas damper adjustment device to adjust the above-mentioned limit parameters within the specified range.

[0146] The embodiment of the present invention also provides a boiler system, including a boiler divided flue and a flue gas damper installed in the boiler divided flue, the boiler divided flue includes a front flue and a rear flue, the front flue and the rear flue are provided with a flue gas measuring device, and the flue gas damper is connected to a variable speed regulating device. The flue gas measuring device is used to measure the flue gas temperature of the front flue and the rear flue in real time, and calculate the optimal value of the flue gas ratio of the front flue and the rear flue under different load conditions according to the flue gas temperature of the front flue and the rear flue. The variable speed regulating device is used to adjust the opening of the flue gas damper to the optimal opening based on the optimal value of the flue gas ratio of the front flue and the rear flue under different load conditions, so that the power supply coal consumption of the boiler is minimized.

[0147] like Figure 2 and Figure 3As shown, the flue gas in the boiler body 5 flows to the denitrification device 7 through the flue. The flue contains a low-temperature reheater 9, a low-temperature superheater 10, main economizers 11, 12 and a flue gas damper 6. A flue gas temperature measuring plane 1, 2 is arranged in the front flue 15 and the rear flue 16 in front of the flue gas damper 6, and the thermocouples 13, 14 are kept 100mm away from the upper edge of the vertical position of the flue gas damper 6. A flue gas temperature measuring plane 3, 4 is arranged in the left flue 19 and the right flue 20 behind the flue gas damper 6, and the distance between the flue temperature measuring plane 3, 4 and the ammonia injection grid 8 is 500mm. The flue temperature measuring planes of the front flue 15 and the rear flue 16 in front of the flue gas damper are arranged with three flue temperature measuring point thermocouples 13, 14 according to the simple grid method. The front and rear flues are divided into three equal-area rectangles with a side length a in the width direction, and the flue temperature measuring points are arranged at the intersection of the diagonals of each rectangle. The left flue 19 and the right flue 20 behind the flue gas damper are each arranged with three smoke temperature measuring point thermocouples 17 and 18 according to the simple grid method. The left and right flues are each divided into three rectangles of equal area with a side length of b in the width direction. The smoke temperature measuring points are arranged at the intersection of the diagonals of each rectangle. A wear-resistant stainless steel temperature sleeve is installed horizontally at each smoke temperature measuring point, and the sleeve is fixed to the furnace wall with screws. Thermocouples are used to measure the smoke temperature. The measurement range of the thermocouple meets the local smoke temperature variation range requirements, and the measurement error is no more than ±1%. The thermocouple millivolt signal is connected to the temperature card of the thermal control cabinet 21 by a compensation wire with similar performance to the thermocouple. The temperature card converts the thermocouple millivolt signal into a digital signal through an instrument amplifier and a converter, and transmits it to the host computer 22 through the DPU (controller).

[0148] like Figure 4 As shown, the speed regulating device includes: a speed regulating unit 23, a speed-changing bidirectional servo motor 24, a transmission 25 and a connecting rod mechanism. The speed regulating unit 23 and the speed-changing bidirectional servo motor 24 are used to control the speed-changing bidirectional servo motor 24. The speed-changing bidirectional servo motor 24 is connected to the transmission 25, the transmission 25 is connected to the connecting rod mechanism 26, and the connecting rod mechanism 26 is connected to the smoke damper 6. The speed regulating unit adopts a variable frequency (or permanent magnet) speed regulating device to realize the speed-changing function of the bidirectional servo motor. The bidirectional servo motor drives the transmission, and the driven shaft of the transmission further drives the smoke damper connecting rod actuator, and the smoke damper connecting rod actuator drives the smoke damper to complete the required switching action. The strength of the smoke damper connecting rod actuator meets the speed change requirements, and the smoke damper can adopt any required switching speed within the range of the lowest to the highest load of the unit.

[0149] The flue gas measuring device includes a calculation unit. The calculation unit writes the optimal flue gas damper opening value corresponding to each load condition, and the optimal flue gas damper opening value is the opening of the flue gas damper corresponding to the optimal value of the flue gas ratio between the front flue and the rear flue under each load condition. The calculation unit obtains a feedforward signal and a feedback signal, and the feedforward signal includes the unit load value, the difference between the unit load and the fuel increase / deceleration rate, and the current opening position of the flue gas damper. The feedback signal includes the change rate and oscillation amplitude of the main steam temperature and the reheat steam temperature, the deviation of the main steam temperature and the reheat steam temperature, the amount of superheating and cooling water, and the amount of reheating and cooling water. The calculation unit generates the optimal dynamic opening instruction corresponding to a certain load condition to the target load condition based on the feedforward signal, the feedback signal and the optimal flue gas damper opening value corresponding to each load condition, and outputs the optimal dynamic opening instruction to the variable speed adjustment device. The speed regulating device adjusts the speed of the variable speed bidirectional servo motor and the speed ratio of the transmission according to the optimal dynamic opening instruction, so as to adjust the opening of the smoke damper to the optimal opening under the target load condition.

[0150] like Figure 5 As shown, the implementation method of the static optimal opening of the front and rear flue flue flue flue dampers is: the optimal opening θ of the front and rear flue flue flues (and the left and right sides) corresponding to each load is implanted into the calculation unit. When the unit target load N2 is adjusted in place and the steam temperature (wall temperature) and the cooling water parameters are stable, the unit load N2 is used as the feedforward signal. After the calculation unit performs comparative calculation, the optimal static opening instruction of the flue gas damper corresponding to the unit load N2 is output to the flue gas damper regulating device. The flue gas damper regulating device adjusts the flue gas damper opening to the optimal static opening under the current load according to the optimal static opening adjustment instruction of the flue gas damper, and the boiler closing parameter is adjusted to the parameter corresponding to the minimum coal consumption of power supply.

[0151] The optimal target of dynamic adjustment of flue gas dampers in front and rear flues is defined as: the process of adjusting the flue gas dampers in front and rear flues from the optimal opening of a certain load N1 to the optimal opening corresponding to the next target load N2 is called dynamic adjustment of flue gas dampers. During the entire dynamic adjustment process, the main and reheat steam temperatures and wall temperatures are in the best state and do not exceed the specified values ​​as much as possible, the main and reheat steam temperatures and wall temperatures change rate does not exceed the specified value, the main and reheat steam temperature deviation does not exceed the specified value (for high and medium pressure combined cylinder units), the main and reheat steam temperature (wall temperature) left and right deviations do not exceed the specified value as much as possible, the main and denitrification device inlet flue gas temperature is not lower than the minimum allowable value, the reheat steam temperature (wall temperature) and cooling water and other related parameters are from the optimal flue gas ratio corresponding parameters of a certain stable load condition to the optimal flue gas ratio corresponding parameters of the target load condition as quickly as possible without abnormal oscillation, the furnace negative pressure is within the normal allowable fluctuation range, and the adjustment process is as economical as possible, then it can be considered that the dynamic adjustment of flue gas dampers has reached the optimal state.

[0152] In this embodiment, the process of adjusting the front and rear flue gas dampers from the optimal opening of a certain load to the optimal opening corresponding to the next target load is called the dynamic adjustment of the flue gas dampers. During the entire dynamic adjustment process, the main and reheat steam temperatures and wall temperatures are in the best state and do not exceed the specified values ​​as much as possible, the main and reheat steam temperatures and wall temperatures change rate does not exceed the specified value, the main and reheat steam temperature deviations do not exceed the specified values ​​as much as possible (for high and medium pressure combined cylinder units), the main and reheat steam temperature (wall temperature) left and right deviations do not exceed the specified values ​​as much as possible, the flue gas temperature at the inlet of the denitrification device is not lower than the minimum allowable value, the reheat steam temperature (wall temperature) and the cooling water and other related parameters reach the corresponding parameters of the optimal flue gas ratio of the target load condition from the corresponding parameters of the optimal flue gas ratio of a certain stable load condition as quickly as possible without abnormal oscillation, the furnace negative pressure is within the normal allowable fluctuation range, and the adjustment process is as economical as possible. It can be considered that the dynamic adjustment of the flue gas damper has reached the optimal state.

[0153] In this embodiment, the optimal flue gas damper opening value corresponding to each load condition is written into the operation unit of the flue gas measuring device, and a feedforward signal and a feedback signal are obtained through the operation unit. The feedforward signal includes the unit load value, the difference between the unit load and the fuel increase / deceleration rate, and the current opening position of the flue gas damper, and the feedback signal includes the change rate and oscillation amplitude of the main steam temperature and the reheat steam temperature, the deviation of the main steam temperature and the reheat steam temperature, the superheating water volume, and the reheating water volume; according to the feedforward signal, the feedback signal and the optimal flue gas damper opening value corresponding to each load condition, an optimal dynamic opening instruction corresponding to a certain load condition to a target load condition is generated, and the optimal dynamic opening instruction is output to the speed regulating device; according to the optimal dynamic opening instruction, the speed of the variable speed bidirectional servo motor of the speed regulating device and the relationship between the speed ratio of the transmission are adjusted to adjust the opening of the flue gas damper to the optimal opening under the target load condition, thereby realizing dynamic optimization of the flue gas damper opening.

[0154] In the boiler system provided in the embodiment of the present invention, the specific method of realizing static / dynamic optimization and static / dynamic adjustment of the flue gas damper opening can be understood by referring to the specific description of the adjustment method of the variable speed flue gas damper in the above embodiment, and will not be repeated here.

[0155] Compared with the prior art, the present invention has the following beneficial effects:

[0156] 1. Based on the flue gas temperature difference between the front and rear flue and the flue gas temperature before and after the flue gas damper, the online measurement, calculation and visualization of the flue gas ratio in the separated flue can be realized. Compared with the flue gas velocity measurement, it can avoid the problems of high velocity measurement process requirements, complex system, many measuring points and equipment, large investment, large maintenance, and untimely backblowing affecting the measurement accuracy. It can avoid the equipment risks caused by inadequate control and over-adjustment of steam temperature and cooling water due to qualitative judgment based on the flue gas damper opening, poor accuracy in adjusting the flue gas ratio, and fear of deep adjustment, thereby improving the economic efficiency of boiler operation and avoiding equipment risks;

[0157] 2. The flue gas damper actuator is a variable speed actuator. It adopts different switching speeds to provide equipment conditions for different variable load rates, fuel increase / deceleration rates, and different damper opening positions (based on the relationship between the damper opening and the flue gas volume) under various load conditions to ensure the linearity of the adjustment effect.

[0158] 3. Taking into account various influencing factors and adjustment needs, the optimal target definition of dynamic and static adjustment of flue gas dampers is clarified to avoid blind dynamic and static adjustment and ensure correct and reasonable adjustment;

[0159] 4. Based on the existing steam temperature (wall temperature), cooling water and other feedback signals, the unit load and change rate, fuel change rate, and flue gas damper opening signals are introduced into the flue gas damper automatic control system as feedforward control signals to improve the steam temperature adjustment hysteresis and oscillation problems caused by only using steam temperature (wall temperature) and cooling water feedback signals for adjustment. The flue gas damper is automatically put into operation to ensure the timeliness and rationality of the adjustment;

[0160] 5. For the various parameters affected by the flue gas damper opening, with power generation coal consumption and safety as the optimization goals, under safe conditions, under different coal types and different boiler load conditions, the parameter values ​​corresponding to each damper opening are determined through optimization tests, the influence of each parameter on power generation coal consumption is calculated, and the flue gas damper opening corresponding to the lowest power generation coal consumption under different coal types and different boiler load conditions is determined, thereby achieving comprehensive static optimization of the flue gas damper opening on various influencing parameters.

[0161] The present invention seeks the optimal flue gas damper switching speed for different flue gas damper opening positions (based on the relationship characteristics between the damper opening and the flue gas volume) through experiments under different variable load rates and fuel increase / deceleration rates in various load conditions, ensures that the flue gas volume, steam temperature (wall temperature) and cooling water meet safety and economic needs within any same time during the flue gas damper switching process, realizes dynamic process optimization, solves the temperature adjustment hysteresis and oscillation phenomena caused by the constant speed actuator, avoids steam temperature (wall temperature) over-temperature or change rate, steam temperature deviation, furnace negative pressure, denitrification device inlet flue gas temperature and the like exceeding the specified values, ensures that the flue gas damper is automatically put into operation, and ensures timeliness and rationality of adjustment.

[0162] The optional embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the technical concept of the embodiments of the present invention, a variety of simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all belong to the protection scope of the embodiments of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction, and as long as the combination does not violate the concept of the embodiments of the present invention, it should also be regarded as the content disclosed in the embodiments of the present invention.

Claims

1. A method for adjusting a variable speed flue gas damper, wherein the flue gas damper is installed in a boiler divided flue, the boiler divided flue comprising a front flue and a rear flue, characterized in that: A flue gas measuring device is provided in the front flue and the rear flue, and the flue gas damper is connected to the speed regulating device. The method comprises: The flue gas temperature of the front flue and the rear flue is measured in real time by a flue gas measuring device; According to the flue gas temperature of the front flue and the rear flue, calculate the optimal value of the flue gas ratio between the front flue and the rear flue under different load conditions; Based on the optimal value of the flue gas ratio between the front flue and the rear flue under different load conditions, the opening of the flue gas damper is adjusted to the optimal opening through the variable speed regulating device, so that the boiler's power supply coal consumption is minimized.

2. The method for adjusting a variable speed smoke damper according to claim 1, characterized in that: The flue gas measuring device comprises a plurality of smoke temperature measuring points, which are respectively arranged at the front flue and the rear flue in front of the smoke damper and the front flue and the rear flue behind the smoke damper.

3. The method for adjusting a variable speed smoke damper according to claim 1, characterized in that: According to the flue gas temperature of the front flue and the rear flue, the optimal value of the flue gas ratio between the front flue and the rear flue under different load conditions is calculated, including: Calculate the comprehensive impact of main steam temperature, reheat steam temperature, superheating water volume, reheating water volume, exhaust temperature and flue gas damper resistance on power supply coal consumption corresponding to different flue gas ratio values ​​of the front flue and the rear flue under different load conditions, and take the flue gas ratio of the front flue and the rear flue with the smallest comprehensive impact value under a certain load condition as the optimal flue gas ratio for that load condition.

4. The method for adjusting a variable speed smoke damper according to claim 3, characterized in that: The calculation formula for the influence of main steam temperature on power supply coal consumption corresponding to different flue gas ratio values ​​of the front flue and the rear flue is: Δb i zqw =(k i zqw *q cs *10) / (η gl *η gd *29308*(1-C); Where Δb i zqw is the impact value of the main steam temperature deviation from the rated value on the power supply coal consumption corresponding to the flue gas ratio i of the front flue and the rear flue under the corresponding load condition; k i zqw is the correction coefficient of the main steam temperature to the heat rate of the steam turbine corresponding to the ratio i of the flue gas in the front flue and the rear flue under the corresponding load condition; q cs is the heat rate of the steam turbine after correction of the corresponding load condition parameters, η gl is the corrected test thermal efficiency of the boiler corresponding to the load condition, η gd is the unit pipeline efficiency, C is the unit power plant power consumption rate under the corresponding load condition; The calculation formula for the impact of reheat steam temperature on power supply coal consumption is: Δb i zrw =(k i zrw *q cs *10) / (η gl *η gd *29308*(1-C); Where Δb i zrw is the impact of the reheat steam temperature deviation from the rated value corresponding to the flue gas ratio value i on the power supply coal consumption under the corresponding load condition; k i zrw is the correction coefficient of the reheat steam temperature corresponding to the flue gas ratio i on the steam turbine heat rate under the corresponding load condition, which is the difference between the reheat steam temperature corresponding to the flue gas ratio i under the corresponding load condition and the rated reheat steam temperature; The calculation formula for the impact of superheated desuperheating water volume on power supply coal consumption is: Δb i gjw =(0.011*G i gjw *G e zq ) / (G zq *(1-C)); Where Δb i gjw G is the impact of the amount of superheating and cooling water corresponding to the flue gas ratio i on the power supply coal consumption under the corresponding load condition, i gjw G is the amount of superheating water for flue gas ratio i corresponding to the load condition. e zq is the main steam volume of the steam turbine under THA condition, G zq is the main steam volume of the steam turbine corresponding to the load condition; The calculation formula for the impact of reheating water volume on power supply coal consumption is: Δb i zjw =(k i zjw *q cs *10) / (η gl *η gd *29308*(1-C); Where Δb i gjw is the impact of the reheating and cooling water volume corresponding to the flue gas ratio i on the power supply coal consumption under the corresponding load condition, K i zjw is the correction coefficient of the reheating water volume corresponding to the flue gas ratio i on the heat rate of the steam turbine corresponding to the load condition; The calculation formula for the influence of exhaust gas temperature on power supply coal consumption is: Δb i p y=((0.05~0.06)*(t i py -t e py )*q cs ) / (100*η e gl *η gl *η gd *29308*(1-C); Where Δb i py is the influence value of exhaust gas temperature corresponding to flue gas ratio i on power supply coal consumption under corresponding load conditions, t i py is the exhaust gas temperature corresponding to the load condition and the flue gas ratio i, t e py is the design exhaust gas temperature corresponding to the load condition, η e gl The design boiler efficiency for the corresponding load condition; The calculation formula of the influence of smoke damper resistance on power supply coal consumption is: Δb i zl =(Δp i zl *C yf *q cs ) / (100*Δp yf *(1-C) 2 *or gl *or gd *29308); Where Δb i zl is the influence value of the flue gas damper resistance corresponding to the flue gas ratio i on the power supply coal consumption under the corresponding load condition, Δp i zl is the flue gas damper resistance corresponding to the flue gas ratio i under the corresponding load condition, C yf is the power consumption rate of the induced draft fan corresponding to the load condition, Δp yf is the static pressure rise of the induced draft fan corresponding to the load condition.

5. The method for adjusting a variable speed smoke damper according to claim 1, characterized in that: Based on the optimal value of the smoke ratio between the front flue and the rear flue under different load conditions, the opening of the smoke damper is adjusted to the optimal opening through the variable speed regulating device, including: The opening of the smoke damper corresponding to the optimal value of the smoke ratio between the front smoke duct and the rear smoke duct under the current load condition is taken as the optimal smoke damper opening value under the load condition; According to the optimal smoke damper opening value corresponding to each load condition, the operating parameters of the variable speed regulating device are determined, and the opening of the smoke damper is made to be the optimal opening by adjusting the operating parameters of the variable speed regulating device.

6. The method for adjusting a variable speed smoke damper according to claim 5, characterized in that: According to the optimal smoke damper opening value corresponding to each load condition, the operating parameters of the variable speed regulating device are determined, and the opening of the smoke damper is made optimal by adjusting the operating parameters of the variable speed regulating device, including: The optimal flue gas damper opening value corresponding to each load condition is written into the calculation unit; A feedforward signal including the unit load value is obtained through the computing unit, an optimal static opening instruction corresponding to the unit load value is generated according to the optimal flue gas damper opening value and the feedforward signal including the unit load value, and the optimal static opening instruction is output to the variable speed regulating device; The speed of the variable speed bidirectional servo motor of the variable speed regulating device and the relationship between the speed ratio of the transmission are adjusted according to the optimal static opening instruction to adjust the opening of the smoke damper to the optimal opening under the current load condition.

7. The method for adjusting a variable speed smoke damper according to claim 5, characterized in that: According to the optimal smoke damper opening value corresponding to each load condition, the operating parameters of the variable speed regulating device are determined, and the opening of the smoke damper is made optimal by adjusting the operating parameters of the variable speed regulating device, including: The optimal flue gas damper opening value corresponding to each load condition is written into the calculation unit; The feedforward signal and feedback signal are obtained through the computing unit, wherein the feedforward signal includes the unit load value, the difference between the unit load and the fuel increase / deceleration rate, and the current opening position of the flue gas damper, and the feedback signal includes the change rate and oscillation amplitude of the main steam temperature and the reheat steam temperature, the deviation of the main steam temperature and the reheat steam temperature, the superheating desuperheating water volume, and the reheating desuperheating water volume; According to the feedforward signal, the feedback signal and the optimal flue gas damper opening value corresponding to each load condition, an optimal dynamic opening instruction corresponding to a certain load condition to a target load condition is generated, and the optimal dynamic opening instruction is output to the variable speed regulating device; The speed of the variable speed bidirectional servo motor of the variable speed regulating device and the relationship between the speed ratio of the transmission are adjusted according to the optimal dynamic opening instruction to adjust the opening of the smoke damper to the optimal opening under the target load condition.

8. A boiler system, comprising a boiler divided flue and a flue gas damper installed in the boiler divided flue, wherein the boiler divided flue comprises a front flue and a rear flue, characterized in that: Also includes: A smoke measuring device and a speed regulating device, wherein the smoke measuring device is arranged in the front smoke duct and the rear smoke duct, and the speed regulating device is connected to the smoke damper; The flue gas measuring device is used to measure the flue gas temperature of the front flue and the rear flue in real time, and calculate the optimal value of the flue gas ratio between the front flue and the rear flue under different load conditions according to the flue gas temperature of the front flue and the rear flue; The variable speed regulating device is used to adjust the opening of the flue gas damper to the optimal opening based on the optimal value of the flue gas ratio between the front flue and the rear flue under different load conditions, so as to minimize the power supply coal consumption of the boiler.

9. The boiler system according to claim 8, characterized in that: The speed-changing regulating device comprises: a speed-changing bidirectional servo motor, a transmission and a connecting rod mechanism, wherein the speed-changing bidirectional servo motor is connected to the transmission, the transmission is connected to the connecting rod mechanism, and the connecting rod mechanism is connected to the smoke damper.

10. The boiler system according to claim 9, characterized in that: The smoke measuring device comprises: a computing unit; The calculation unit is used to write the optimal smoke damper opening value corresponding to each load condition, and the optimal smoke damper opening value is the opening of the smoke damper corresponding to the optimal value of the smoke ratio of the front flue and the rear flue under each load condition; The computing unit is used to obtain a feedforward signal and a feedback signal, wherein the feedforward signal includes the unit load value, the difference between the unit load and the fuel increase / deceleration rate, and the current opening position of the flue gas damper, and the feedback signal includes the change rate and oscillation amplitude of the main steam temperature and the reheat steam temperature, the deviation of the main steam temperature and the reheat steam temperature, the superheating desuperheating water volume, and the reheating desuperheating water volume; The computing unit generates an optimal dynamic opening instruction corresponding to a certain load condition to a target load condition according to the feedforward signal, the feedback signal and the optimal smoke damper opening value corresponding to each load condition, and outputs the optimal dynamic opening instruction to the variable speed regulating device; The speed adjustment device adjusts the speed of the variable speed bidirectional servo motor and the speed ratio of the transmission according to the optimal dynamic opening instruction to adjust the opening of the smoke damper to the optimal opening under the target load condition.

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