A method and system for correcting the amount of ammonia injection in a coal-fired power plant based on chimney monitoring of NOx concentration

Abstract

The present invention discloses a method and system for correcting the ammonia injection amount in a coal-fired power plant based on NOx concentration monitoring in a chimney, belonging to the technical field of ammonia injection control in the denitration system of a thermal power generating unit. By utilizing the lag of NOx concentration monitored in the chimney for environmental protection and the potential calculation method of the SCR reactor, the true SCR outlet NOx concentration at the current moment can be inferred; the reactor potential is calculated based on the chimney NOx concentration and the historical data at time T0, and it is approximately considered that the potential at time T1 is the same as that at time T0. Thus, the reactor potential at time T1 is deduced, and the actual SCR outlet NOx concentration C at time T1 is calculated in combination with the known quantities at time T1. NOx,out , the ammonia slip concentration #imgabs0#, and is compared with the set value of the SCR outlet NOx concentration. Further, the ammonia injection correction amount is calculated and applied to the ammonia injection control valve through the control system to realize the real-time correction of the ammonia injection amount.

Description

Technical Field

[0001] The invention belongs to the field of ammonia nitrogen concentration acquisition in coal-fired power plants, and relates to a method and system for correcting ammonia injection amount in coal-fired power plants based on chimney monitoring of NOx concentration. Background Art

[0002] The coal quality and load of coal-fired units are relatively stable, and the control requirements for NOx emission concentration are relatively low. The total amount of ammonia injection is usually controlled by a simple fixed molar ratio. The operating conditions of coal-fired units are harsh and changeable, and a cascade closed-loop ammonia injection total amount control system is generally adopted. Because the SCR system has inherent characteristics such as large time delay, large lag, and nonlinearity, the total amount of ammonia injection control has common problems such as adjustment lag and large fluctuations. Especially under the current dual pressures of ultra-low emissions and flexible peak regulation faced by coal-fired units, this problem is further highlighted. The low quality of total ammonia injection control affects the unit's NOx emission compliance and limits the unit's flexible peak regulation capability. On the other hand, it causes the instantaneous ammonia escape concentration to be too high, exacerbating the ABS contamination and blockage of downstream equipment such as air preheaters.

[0003] A method and system for automatic adjustment and optimization of boiler denitration ammonia injection mentioned in the prior art obtains the amount of exhaust gas discharged by the boiler and the nitrogen oxide concentration at the inlet of the denitration reactor, and multiplies the exhaust gas amount by the nitrogen oxide concentration to obtain the total nitrogen oxide content in the exhaust gas; obtains the nitrogen oxide emission content at the desulfurization outlet, and calculates the difference between the total nitrogen oxide content and the nitrogen oxide emission content; uses the difference between the total nitrogen oxide content and the nitrogen oxide emission content as the nitrogen oxide reaction amount, and selects the ammonia injection amount that catalytically reacts with the corresponding nitrogen oxide reaction amount from the preset ammonia injection amount database and injects it into the denitration reactor. This invention uses the difference between the total nitrogen oxide content and the nitrogen oxide emission content as the nitrogen oxide reaction amount, and selects the ammonia injection amount that catalytically reacts with the corresponding nitrogen oxide reaction amount from the preset ammonia injection amount database and injects it into the denitration reactor. However, this method does not take into account the hysteresis of the measurement.

[0004] A denitration ammonia injection control method based on multivariable correction mentioned in the prior art obtains the measurement data and operating condition information of the denitration system instrument in real time; constructs a prediction model for the NOx content at the inlet of the SCR denitration system to predict the NOx content at the inlet of the SCR system at the current moment; based on the above-predicted NOx content and measurement data at the inlet of the SCR system, performs ammonia injection amount feedforward control and prediction correction, generates ammonia injection amount control instructions at the current moment, controls the ammonia injection regulating valve, and adjusts the ammonia injection amount. However, there are many factors affecting the NOx content at the inlet of the SCR, and it is difficult for the prediction model to make accurate predictions. Summary of the invention

[0005] The purpose of the present invention is to solve the problem in the prior art that there is a lag in the measurement of boiler denitrification ammonia injection, which makes it difficult to make accurate predictions, and to provide a method and system for correcting the ammonia injection amount of a coal-fired power plant based on chimney monitoring of NOx concentration.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention proposes a method for correcting the amount of ammonia injected in a coal-fired power plant based on chimney monitoring of NOx concentration, comprising the following steps:

[0008] Obtaining the denitration efficiency at the initial moment, and obtaining the expression of the injection amount of ammonia at the initial moment and the expression of the denitration reactor potential at the initial moment according to the denitration efficiency at the initial moment;

[0009] Obtaining a potential expression at a certain moment according to the potential expression of the denitrification reactor at the initial moment;

[0010] Obtain the accurate ammonia nitrogen concentration relationship at the SCR outlet at a certain moment based on the potential expression at a certain moment;

[0011] The change trend of ammonia injection amount is obtained according to the accurate ammonia nitrogen concentration relationship of the SCR outlet at a certain moment, so as to realize the correction of ammonia injection amount of the power plant.

[0012] Preferably, the denitration efficiency η at the initial moment is obtained T0 The method is as follows:

[0013]

[0014] Among them, C NOx,in,T0 is the NOx concentration at the SCR inlet at the initial time, C NOx,out,T0 is the NOx concentration at the SCR outlet at the initial time T0.

[0015] Preferably, the expression for obtaining ammonia slip at the initial moment is as follows:

[0016]

[0017] Among them, Q NH3,T0 is the amount of ammonia injected at the initial moment, Q 烟气,T0 is the smoke volume at the initial moment, C NH3,T0 is the ammonia escape concentration at the initial moment.

[0018] Preferably, the denitration reactor potential expression at the initial moment is obtained as follows:

[0019]

[0020] Among them, P T0 is the reactor potential at the initial moment, MR T0 is the NH at the initial moment3 / NOx molar ratio.

[0021] Preferably, the NH at the initial moment is obtained. 3 The method of / NOx molar ratio is as follows:

[0022]

[0023] Preferably, the potential expression at a certain moment is as follows:

[0024]

[0025] Among them, P T0 is the reactor potential at the initial moment, P T1 is the reactor potential at a certain time T1, and the denitrification efficiency at a certain time

[0026] Preferably, the ammonia nitrogen concentration relationship is as follows:

[0027]

[0028] The present invention proposes a coal-fired power plant ammonia injection correction system based on chimney monitoring of NOx concentration, comprising:

[0029] A power plant initial data acquisition module, which is used to acquire the denitration efficiency at the initial moment, and acquire the ammonia injection amount expression at the initial moment and the denitration reactor potential expression at the initial moment according to the denitration efficiency at the initial moment;

[0030] A potential expression acquisition module at a certain moment, wherein the potential expression acquisition module at a certain moment is used to acquire a potential expression at a certain moment according to a potential expression of a denitration reactor at an initial moment;

[0031] An accurate ammonia nitrogen concentration relationship acquisition module, the accurate ammonia nitrogen concentration relationship acquisition module is used to obtain an accurate ammonia nitrogen concentration relationship expression at the SCR outlet at a certain moment according to a potential expression at a certain moment;

[0032] The ammonia injection amount variation trend acquisition module is used to obtain the ammonia injection amount variation trend according to the accurate ammonia nitrogen concentration relationship at the SCR outlet at a certain moment, so as to realize the ammonia injection amount correction of the power plant.

[0033] A computer device comprises a memory and a processor, wherein the memory stores a computer program and the processor implements the steps of a method for correcting the amount of ammonia injection in a coal-fired power plant based on chimney monitoring of NOx concentration when executing the computer program.

[0034] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a method for correcting the amount of ammonia injection in a coal-fired power plant based on chimney monitoring of NOx concentration.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The present invention proposes a method for correcting the amount of ammonia injection in a coal-fired power plant based on chimney monitoring of NOx concentration. By utilizing the hysteresis of the chimney environmental monitoring of NOx concentration and the potential of the SCR reactor, the real SCR outlet NOx concentration at the current moment can be inferred; the reactor potential is obtained according to the historical data of the chimney NOx concentration and the initial moment, and it is approximately considered that the potential at a certain moment and the initial moment is constant, thereby deducing the reactor potential at a certain moment, and combining the known quantity at a certain moment to calculate the actual SCR outlet NOx concentration and ammonia escape concentration at a certain moment, and compare it with the SCR outlet NOx concentration set value to obtain the ammonia injection correction amount, and act on the ammonia injection regulating valve through the control system to achieve real-time correction of the ammonia injection amount. Therefore, the correction method proposed by the present invention can solve the problems existing in the prior art.

[0037] The present invention proposes a coal-fired power plant ammonia injection correction system based on chimney monitoring of NOx concentration, which realizes the correction of power plant ammonia injection by dividing the system into a power plant initial data acquisition module, a potential expression acquisition module at a certain moment, an accurate ammonia nitrogen concentration relationship acquisition module and an ammonia injection change trend acquisition module. The modular concept is adopted to make each module independent of each other, which is convenient for unified management of each module. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 The present invention is a flow chart of a method for correcting the amount of ammonia injected in a coal-fired power plant based on chimney monitoring of NOx concentration.

[0040] Figure 2 The figure is a detailed flowchart of the method for correcting the amount of ammonia injection in a coal-fired power plant based on chimney monitoring of NOx concentration according to the present invention.

[0041] Figure 3 This is a diagram of the ammonia injection amount correction system for a coal-fired power plant based on chimney monitoring of NOx concentration according to the present invention. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0045] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0046] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0047] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0049] The NOx measurement elements of coal-fired power plants are mainly distributed at the SCR inlet, SCR outlet, and chimney environmental monitoring port. Measurements at different locations have different characteristics: the SCR inlet NOx concentration meter is closest to the ammonia injection main pipe and the ammonia injection regulating valve, so the data is most timely. At the same time, due to the high magnitude and uniform distribution of the inlet NOx concentration, the representativeness is also relatively good; the SCR outlet NOx concentration meter is closer to the ammonia injection regulating valve, and it takes a short time for the flue gas to flow from the SCR inlet to the outlet, usually 10s to 20s, with a certain lag, but the outlet NOx concentration distribution is usually uneven, especially in the context of ultra-low emissions, the values ​​are small and low, so the representativeness is poor; the NOx meter at the chimney environmental monitoring port has a higher accuracy, mainly because the flue gas has been fully mixed after passing through the SCR, air preheater, dust removal device, and desulfurization device, and is very uniform and representative, but the lag is serious, because the flue gas flow velocity is usually not high and the tail flue distance is long, the lag is usually 1 minute or even longer.

[0050] In general, the NOx concentration at the SCR inlet is more representative and timely, the NOx concentration at the SCR outlet is more timely but less representative, and the environmental monitoring port at the chimney is more representative but less timely. Currently, coal-fired units are facing the requirement of flexible peak regulation, that is, the load (flue gas volume) and inlet NOx concentration fluctuate greatly, and the ammonia injection amount is directly related to the load (flue gas volume), inlet NOx concentration, and outlet NOx concentration. Obviously, under the background of flexible peak regulation, the relevant parameters vary greatly, so the ammonia injection amount will also fluctuate greatly. In order to reduce fluctuations, higher requirements are put forward for the representativeness and timeliness of relevant parameters.

[0051] According to the above analysis, the NOx concentration at the SCR inlet is representative and timely, so there is no problem with participating in the control. However, if the SCR outlet NOx concentration is measured by the SCR outlet meter, the value is timely but representative, while if the chimney environmental monitoring port is used, the value is representative but timeliness is poor, and both cannot be taken into account. In order to solve this problem, power plants usually use multi-point sampling and other methods to improve the representativeness of the SCR outlet NOx meter. However, multi-point sampling requires the modification of on-site equipment, and the existing technology also has the problems of easy clogging and high failure rate.

[0052] The starting point of the present invention is to use the NOx concentration data of the chimney environmental monitoring port (hereinafter referred to as chimney NOx concentration) to control ammonia injection, predict the NOx emission concentration after a period of time through potential calculation, and correct the ammonia injection amount accordingly.

[0053] The present invention proposes a method for correcting the amount of ammonia injected in a coal-fired power plant based on chimney monitoring of NOx concentration. Figure 1 As shown, the following steps are included:

[0054] S1. Obtaining the denitration efficiency at the initial moment, and obtaining the ammonia slip expression at the initial moment and the denitration reactor potential expression at the initial moment according to the denitration efficiency at the initial moment;

[0055] Get the denitrification efficiency η at the initial time T0 The method is as follows:

[0056]

[0057] Among them, C NOx,in,T0 is the NOx concentration at the SCR inlet at the initial time, C NOx,out,T0 is the NOx concentration at the SCR outlet at the initial time T0.

[0058] The formula for obtaining the accurate SCR outlet NOx concentration at the initial time T0 is as follows:

[0059] C NOx,out,T0 =C NOx,烟囱,T1

[0060] Among them, C NOx,out,T0 is the SCR outlet NOx concentration at the initial time T0, C NOx,烟囱,T1 is the chimney NOx concentration at time T1.

[0061] The expression for obtaining ammonia slip at the initial time is as follows:

[0062]

[0063] Among them, Q NH3,T0 is the amount of ammonia injected at the initial moment, Q 烟气,T0 is the smoke volume at the initial moment, C NH3,T0 is the ammonia escape concentration at the initial moment.

[0064] The potential expression of the denitrification reactor at the initial moment is as follows:

[0065]

[0066] Among them, P T0 is the reactor potential at the initial moment, MR T0 is the NH at the initial moment 3 / NOx molar ratio.

[0067] Get the NH at the initial moment 3 The method of / NOx molar ratio is as follows:

[0068]

[0069] S2. Obtaining a potential expression at a certain moment according to the potential expression of the denitrification reactor at the initial moment;

[0070] The potential expression at a certain moment T1 is as follows:

[0071]

[0072] Among them, P T0 is the reactor potential at the initial moment, P T1 is the reactor potential at a certain time T1, and the denitrification efficiency at a certain time

[0073] S3. Obtain the accurate ammonia nitrogen concentration relationship at the SCR outlet at a certain moment according to the potential expression at a certain moment;

[0074] The relationship between ammonia nitrogen concentration is as follows:

[0075]

[0076] S4. Obtain the change trend of ammonia injection amount based on the accurate ammonia nitrogen concentration relationship at the SCR outlet at a certain moment, and realize the correction of ammonia injection amount in the power plant.

[0077] like Figure 2 As shown, the specific steps are as follows:

[0078] Assuming that the SCR outlet flue gas flows from the SCR outlet to the chimney environmental monitoring port, ΔT, the initial time T0 and a certain time T1 need to satisfy the following relationship:

[0079] T1-T0=ΔT (1)

[0080] That is to say, the NOx concentration at the chimney environmental monitoring port measured at a certain time T1 is actually the NOx concentration at the SCR outlet at the initial time T0. After ΔT, this flue gas flows into the chimney. This value is used to replace the SCR outlet NOx concentration value at the initial time T0. Since it has been mixed by various devices in the tail flue, this value is accurate, so we can get formula (2):

[0081] C NOx,out,T0 =C NOx,烟囱,T1 (2)

[0082] At the same time, since the SCR inlet NOx concentration, flue gas volume, and ammonia injection amount at the initial time T0 are known (these parameter measurement points are all near the ammonia injection regulating valve, and the accuracy is also high), then combined with the chimney NOx concentration at a certain time T1, the accurate SCR inlet NOx concentration, SCR outlet NOx concentration, flue gas volume, and ammonia injection amount at the initial time T0 can be obtained. The denitrification efficiency at the initial time T0 can be calculated, and the actual ammonia slip can be further deduced based on the ammonia injection amount formula. The calculation formula is as follows:

[0083]

[0084]

[0085] Among them, C NOx,in,T0 is the NOx concentration at the SCR inlet at the initial time (6%O 2 , mg / m 3 );C NOx,out,T0 is the NOx concentration at the SCR outlet at the initial time (6%O 2 , mg / m 3 ), this parameter is obtained by formula (2), η T0 is the denitrification efficiency at the initial moment, %; Q NH3,T0 is the amount of ammonia sprayed at the initial moment, kg / h; Q 烟气,T0 is the smoke volume at the initial moment, m 3 / h; C NH3,T0 is the ammonia escape concentration at the initial moment, μL / L.

[0086] Obviously, the denitrification efficiency η can be calculated based on the SCR inlet NOx concentration and the SCR outlet NOx concentration. T0 , and further calculate the ammonia slip concentration C according to the ammonia injection amount, flue gas volume, and inlet NOx concentration NH3,T0 .

[0087] Furthermore, the potential parameter P is introduced. The potential of the denitrification reactor can be used to reflect the overall performance status under the current actual flue gas conditions and predict the maximum safe denitrification efficiency corresponding to the upper limit of ammonia escape under the rated load of the unit. It can also be used as process data for prediction and evaluation of efficiency improvement transformation of the denitrification device. The potential calculation formula is shown in formula (5), where the efficiency η involved is T0 It is known that MR T0 (NH 3 / NOx molar ratio) can be calculated according to formula (6), where the efficiency η T0 、Ammonia escape concentration C NH3,T0 、SCR inlet NOx concentration C NOx,in,T0 All are known, so the potential can be calculated.

[0088]

[0089]

[0090] Among them, P T0 is the reactor potential at the initial moment; MR T0 NH is the initial moment 3 / NOx molar ratio.

[0091] Through the above calculation, the SCR reactor potential P at the initial time T0 can be obtained: T0, since the potential decreases very slowly, usually 8% to 12% a year, the potential is usually around 2 to 4, that is, it changes by 0.16 to 0.48 per year, which is a very small value. The thermal power unit is calculated based on 6000 hours of utilization, and the change per hour is 0.00008, and the change per minute is even smaller. Considering the time interval between T0 and T1, that is, the time for the flue gas to flow from the desulfurization outlet to the chimney, which is usually 1 minute or longer, it can be approximately considered that the potential at T1 is the same as the potential at T0, so the potential at T1 is obtained, that is:

[0092] P T1 =P T0 (7)

[0093] When the potential at a certain moment T1 is known, the actual outlet NOx concentration at this time can be deduced from equations (2) to (6). The calculation formulas are the same. All subscripts T0 can be replaced by T1. The deduction process is as follows:

[0094]

[0095]

[0096] in,

[0097] At a certain time T1, the flue gas volume Q 烟气,T1 、SCR inlet NOx concentration C NOx,in,T1 、Ammonia injection amount Q NH3,T1 , Potential T1 All are known, the only unknown quantity is the NOx concentration C at the SCR outlet. NOx,out,T1 、Ammonia escape concentration C NH3,T1 , denitrification efficiency η T1 , which is a three-variable linear equation, SCR outlet NOx concentration C NOx,out,T1 、Ammonia escape concentration C NH3,T1 , denitrification efficiency η T1 It can be calculated.

[0098] If C NOx,out,T1 If it is too high, it means that less ammonia is injected. After ΔT, the chimney NOx concentration is too high. In this case, the control system will increase the amount of ammonia injection to reduce C NOx,out,T1 ; if C NOx,out,T1 If it is too low, it means that the amount of ammonia sprayed is too much. After ΔT, the chimney NOx concentration is too low. In this case, the control system will give a correction amount to reduce the amount of ammonia sprayed, which can improve C NOx,out,T1 The correction amount can be obtained according to the ammonia injection amount calculation formula, for example, C NOx,out,T1 Too high 5mg / m 3, combined with the flue gas volume, the required increase in ammonia injection amount is the amount of ammonia injection required to react to so much NOx.

[0099] In summary, after calculation, at time T1, the present invention can calculate the reactor potential based on the chimney NOx concentration and the historical data at time T0, and approximately assume that the potentials at time T1 and time T0 are unchanged, thereby deriving the reactor potential at time T1, and combining the known quantities at time T1 to calculate the actual SCR outlet NOx concentration C at time T1. NOx,out,T1 、Ammonia escape concentration C NH3,T1 , denitrification efficiency η T1 The ammonia injection correction amount is further calculated and applied to the ammonia injection regulating valve through the control system to achieve real-time correction of the ammonia injection amount.

[0100] The present invention proposes a coal-fired power plant ammonia injection correction system based on chimney monitoring of NOx concentration, such as Figure 3 As shown, it includes a power plant initial data acquisition module, a potential expression acquisition module at a certain moment, an accurate ammonia nitrogen concentration relationship acquisition module and an ammonia injection amount change trend acquisition module;

[0101] The power plant initial data acquisition module is used to obtain the denitration efficiency at the initial moment, and obtain the ammonia injection amount expression at the initial moment and the denitration reactor potential expression at the initial moment according to the denitration efficiency at the initial moment;

[0102] The potential expression acquisition module at a certain moment is used to acquire the potential expression at a certain moment according to the potential expression of the denitration reactor at an initial moment;

[0103] The accurate ammonia nitrogen concentration relationship acquisition module is used to obtain the accurate ammonia nitrogen concentration relationship of the SCR outlet at a certain moment according to the potential expression at a certain moment;

[0104] The ammonia injection amount variation trend acquisition module is used to obtain the ammonia injection amount variation trend according to the accurate ammonia nitrogen concentration relationship of the SCR outlet at a certain moment, so as to realize the ammonia injection amount correction of the power plant.

[0105] A terminal device provided in an embodiment of the present invention comprises: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps in the above-mentioned method embodiments are implemented. Alternatively, when the processor executes the computer program, the functions of the modules / units in the above-mentioned system embodiments are implemented.

[0106] The computer program may be divided into one or more modules / units, and the one or more modules / units are stored in the memory and executed by the processor to accomplish the present invention.

[0107] The terminal device may be a computing device such as a desktop computer, a notebook, a PDA, a cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0108] The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0109] The memory may be used to store the computer programs and / or modules, and the processor implements various functions of the terminal device by running or executing the computer programs and / or modules stored in the memory and calling the data stored in the memory.

[0110] If the module / unit integrated in the terminal device is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or system that can carry the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0111] The present invention proposes a method and system for correcting the ammonia injection amount of a coal-fired power plant based on chimney monitoring of NOx concentration. By utilizing the hysteresis of the chimney environmental monitoring of NOx concentration and the potential calculation method of the SCR reactor, the actual SCR outlet NOx concentration at the current moment can be inferred and compared with the SCR outlet NOx concentration set value, and the ammonia injection correction amount is further calculated. The ammonia injection regulating valve is acted on by the control system to realize real-time correction of the ammonia injection amount.

[0112] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for correcting the amount of ammonia injected in coal-fired power plants based on chimney monitoring of NOx concentration. It is characterized in that The steps include: Obtaining the denitration efficiency at the initial moment, and obtaining the expression of the injection amount of ammonia at the initial moment and the expression of the denitration reactor potential at the initial moment according to the denitration efficiency at the initial moment; Obtaining a potential expression at a certain moment according to the potential expression of the denitrification reactor at the initial moment; Obtain the accurate ammonia nitrogen concentration relationship at the SCR outlet at a certain moment based on the potential expression at a certain moment; The change trend of ammonia injection amount is obtained based on the accurate ammonia nitrogen concentration relationship at the SCR outlet at a certain moment, so as to realize the correction of ammonia injection amount in the power plant; Get the denitrification efficiency at the initial moment The method is as follows: in, is the NOx concentration at the SCR inlet at the initial time, is the NOx concentration at the SCR outlet at the initial time T0; The expression for obtaining ammonia slip at the initial time is as follows: in, is the amount of ammonia injected at the initial moment, is the smoke volume at the initial moment, is the ammonia escape concentration at the initial moment; The potential expression of the denitrification reactor at the initial moment is as follows: in, is the reactor potential at the initial moment, is the NH at the initial moment 3 / NOx molar ratio; Get the NH at the initial moment 3 The method of / NOx molar ratio is as follows: The potential expression at a certain moment is as follows: in, is the reactor potential at the initial moment, is the reactor potential at a certain time T1, and the denitrification efficiency at a certain time ; The relationship between ammonia nitrogen concentration is as follows: 。 2. A correction system for the method for correcting the amount of ammonia injected in a coal-fired power plant based on chimney monitoring of NOx concentration according to claim 1, It is characterized in that include: A power plant initial data acquisition module, which is used to acquire the denitration efficiency at the initial moment, and acquire the ammonia injection amount expression at the initial moment and the denitration reactor potential expression at the initial moment according to the denitration efficiency at the initial moment; A potential expression acquisition module at a certain moment, wherein the potential expression acquisition module at a certain moment is used to acquire a potential expression at a certain moment according to a potential expression of a denitration reactor at an initial moment; An accurate ammonia nitrogen concentration relationship acquisition module, the accurate ammonia nitrogen concentration relationship acquisition module is used to obtain an accurate ammonia nitrogen concentration relationship expression at the SCR outlet at a certain moment according to a potential expression at a certain moment; The ammonia injection amount variation trend acquisition module is used to obtain the ammonia injection amount variation trend according to the accurate ammonia nitrogen concentration relationship at the SCR outlet at a certain moment, so as to realize the ammonia injection amount correction of the power plant.

3. A computer device comprising a memory and a processor, wherein the memory stores a computer program, It is characterized in that When the processor executes the computer program, the steps of the method for correcting the amount of ammonia injection in a coal-fired power plant based on chimney monitoring of NOx concentration as claimed in claim 1 are implemented.

4. A computer-readable storage medium storing a computer program, It is characterized in that When the computer program is executed by the processor, the steps of the method for correcting the amount of ammonia injection in a coal-fired power plant based on chimney monitoring of NOx concentration as claimed in claim 1 are implemented.

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