Flue gas denitrification system for thermal power plant and control method

Abstract

Provided are a flue gas denitrification system for a thermal power plant and a control method. The system comprises a console end, a DCS control system end, a denitrification reaction end, a flue gas outlet measurement end and a circulation system end. The DCS control system end is connected to the console end, the denitrification reaction end, the flue gas outlet measurement end and the circulation system end, and the circulation system end is connected to the denitrification reaction end and the flue gas outlet measurement end. The problems of excessive ammonia injection, insufficient ammonia injection and the like of existing denitrification systems are solved.

Description

A flue gas denitrification system and control method for a thermal power plant

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on October 24, 2023, with application number 202311385209.X and invention name “A Flue Gas Denitrification System and Control Method for a Thermal Power Plant”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the technical field of flue gas denitrification in thermal power plants, and in particular to a flue gas denitrification system and a control method for a thermal power plant. Background Art

[0004] A thermal power plant, also known as a thermal power plant, is a factory that uses combustible materials (such as coal) as fuel to produce electricity. The power generation process of a thermal power plant is basically to heat water to generate steam when the fuel is burned, converting the chemical energy of the fuel into thermal energy. The steam pressure drives the turbine to rotate, converting the thermal energy into mechanical energy, and then the turbine drives the generator to rotate, converting the mechanical energy into electrical energy. The combustion of fuel will produce flue gas. The nitrogen oxides in the waste flue gas contain a large amount of nitric gas, which will cause air pollution if discharged directly. Therefore, the flue gas needs to be denitrified.

[0005] The existing denitrification ammonia injection systems used in many thermal power plants to remove nitrogen oxides emitted from coal-fired boilers have information lags, and most of the current denitrification ammonia injection systems use a fixed amount of ammonia distribution, which cannot adapt to the variability of nitrogen oxide content in flue gas under different load instruction conditions of the unit. There are problems such as excessive ammonia injection and insufficient ammonia injection. When excessive ammonia injection causes the ammonia escape rate to be too high, it will lead to inconvenience in fly ash treatment, and it is easy to react with sulfur trioxide (SO3) to generate ammonium bisulfate that easily clogs catalysts and air preheaters. In severe cases, it will cause shutdown and waste at the same time. When the amount of ammonia injection is insufficient, the nitrogen oxides cannot meet the emission standards.

[0006] Summary of the Invention

[0007] The present application aims to solve one of the technical problems in the related art at least to a certain extent.

[0008] To this end, the first purpose of this application is to propose a flue gas denitrification system for a thermal power plant to solve the problems of excessive ammonia injection and insufficient ammonia injection in existing denitrification systems.

[0009] The second object of this application is to provide a control method for a flue gas denitrification system in a thermal power plant.

[0010] To achieve the above-mentioned objectives, the first embodiment of the present application proposes a flue gas denitrification system for a thermal power plant, comprising a main engine end, a DCS control system end, a denitrification reaction end, a flue gas outlet detection end, and a circulation system end, wherein the DCS control system end is simultaneously connected to the main engine end, the denitrification reaction end, the flue gas outlet detection end, and the circulation system end, and the circulation system end is connected to the denitrification reaction end and the flue gas outlet detection end;

[0011] The host side is used to generate power generation load instructions;

[0012] The denitrification reaction end is used to spray ammonia and utilize ammonia to react with the flue gas to be denitrified to generate denitrified flue gas, and is also used to collect the flow rate of the flue gas to be denitrified and the amount of ammonia sprayed;

[0013] The flue gas outlet detection end is used to detect the ammonia concentration and nitrogen oxide concentration in the denitrification flue gas;

[0014] The circulation system end is used to generate a feedback instruction based on the flow rate of the flue gas to be denitrated, the amount of ammonia injection, the ammonia concentration and the nitrogen oxide concentration in the denitrated flue gas when the ammonia concentration or the nitrogen oxide concentration in the denitrated flue gas does not meet the emission requirements;

[0015] The DCS control system end is used to control the ammonia injection amount of the denitrification reaction end based on the power generation load instruction, and also to assist in controlling the ammonia injection amount of the denitrification reaction end or the flow rate of the flue gas to be denitrified based on the feedback instruction to perform re-denitrification on the denitrification flue gas, so that the ammonia concentration and nitrogen oxide concentration in the denitrification flue gas meet the emission requirements.

[0016] In the flue gas denitrification system of a thermal power plant provided in the first aspect of the present application, the denitrification reaction end includes an ammonia injection amount adjustment module, a reactor, a flue gas flow detection module, a first data transmission module and a first wireless signal module, the ammonia injection amount adjustment module is connected to the DCS control system end, the reactor includes an ammonia injection pipeline, a first flue gas inlet pipeline, a second flue gas inlet pipeline and a flue gas outlet pipeline, the ammonia injection amount adjustment module is installed on the outside of the ammonia injection pipeline, the first flue gas inlet pipeline transports the flue gas to be denitrified, the flue gas flow detection module is installed inside the first flue gas inlet pipeline, the ammonia injection amount adjustment module and the flue gas flow detection module are respectively connected to the first data transmission module, the first data transmission module is connected to the circulation system end via the first wireless signal module, and the second flue gas inlet pipeline and the flue gas outlet pipeline are respectively connected to the circulation system end.

[0017] In the flue gas denitrification system of a thermal power plant provided in the first aspect of the present application, the ammonia injection amount adjustment module adopts an electrically controlled regulating valve.

[0018] In the flue gas denitrification system of a thermal power plant provided in the first aspect of the present application, the flue gas outlet detection end includes an outlet nitrogen oxide concentration detection module, an outlet ammonia concentration detection module, a second data transmission module and a second wireless signal module, the outlet nitrogen oxide concentration detection module and the outlet ammonia concentration detection module are both installed inside the flue gas outlet pipe, the outlet nitrogen oxide concentration detection module and the outlet ammonia concentration detection module are respectively connected to the second data transmission module, and the second data transmission module is connected to the circulation system end via the second wireless signal module.

[0019] In the flue gas denitrification system of a thermal power plant provided in the first aspect of the present application, the circulation system end includes a third wireless signal module, a data receiving module, a data acquisition module, a data online calculation module, a data processing module, a third data transmission module and a storage. The third wireless signal module is simultaneously connected to the second wireless signal module and the first wireless signal module. The third wireless signal module is also connected to the DCS control system end via the data receiving module, the data acquisition module, the data online calculation module, the data processing module and the third data transmission module. The storage includes a flue gas inlet, a first flue gas outlet and a second flue gas outlet. The flue gas inlet is connected to the flue gas outlet pipe of the denitrification reaction end, and the first flue gas outlet is connected to the second flue gas inlet pipe of the denitrification reaction end.

[0020] In the flue gas denitrification system for a thermal power plant provided in the first aspect of the present application, the first wireless signal module and the second wireless signal module are both wireless signal transmitters, and the third wireless signal module is a wireless signal receiver.

[0021] In the flue gas denitrification system of a thermal power plant provided in the first aspect of the present application, the data online calculation module includes a feedforward nitrogen oxide input compensation logic module, a feedforward ammonia injection compensation logic module and a feedforward nitrogen oxide average value logic module.

[0022] In the flue gas denitrification system of a thermal power plant provided in the first aspect of the present application, the circulation system end also includes a heating module, the heating module includes a heater and a temperature sensor, the heater is installed around the inner wall of the storage, and the temperature sensor is installed on the top of the inner cavity of the storage, and the heater and the temperature sensor are both connected to the DCS control system end.

[0023] To achieve the above-mentioned purpose, the second embodiment of the present application proposes a control method for a flue gas denitrification system in a thermal power plant, comprising:

[0024] When the host side issues a power generation load instruction, the flue gas to be denitrified generated by the thermal power unit enters the reactor at the denitrification reaction end, and the denitrification reaction end sends the collected flue gas flow to the circulation system end;

[0025] When the DCS control system receives the power generation load instruction sent by the host end, the ammonia injection amount of the denitration reaction end is controlled to be the initial injection amount, and the denitration reaction end sends the ammonia injection amount to the circulation system end in real time;

[0026] In the denitration reaction end, ammonia reacts with the flue gas to be denitrated to generate denitrated flue gas, and the flue gas outlet detection end detects the ammonia concentration and nitrogen oxide concentration in the denitrated flue gas and sends the result to the circulation system end;

[0027] The circulation system generates a feedback instruction based on the flow rate of the flue gas to be denitrated, the amount of ammonia injection, the ammonia concentration and the nitrogen oxide concentration in the denitrated flue gas when the ammonia concentration or the nitrogen oxide concentration in the denitrated flue gas does not meet the emission requirements;

[0028] The DCS control system side assists in controlling the ammonia injection amount of the denitrification reaction end or the flow rate of the flue gas to be denitrified based on the feedback instruction to perform re-denitrification on the denitrified flue gas so that the ammonia concentration and the nitrogen oxide concentration in the denitrified flue gas meet the emission requirements.

[0029] In the control method of the flue gas denitrification system of a thermal power plant provided in the second aspect of the present application, the feedback instruction includes a first feedback instruction and a second feedback instruction, and the feedback instruction is generated based on the flow rate of the flue gas to be denitrified, the amount of ammonia sprayed, the ammonia concentration and the nitrogen oxide concentration in the denitrified flue gas when the ammonia concentration or the nitrogen oxide concentration in the denitrified flue gas does not meet the emission requirements, including: if the nitrogen oxide concentration in the denitrified flue gas meets the emission requirements but the ammonia concentration in the denitrified flue gas does not meet the emission requirements, the circulation system end determines based on the flow rate of the flue gas to be denitrified, the amount of ammonia sprayed and the ammonia concentration in the denitrified flue gas The target flow rate of the flue gas to be denitrified is then used to generate a first feedback instruction, so as to control the flue gas to be denitrified at the target flow rate to enter the reactor through the DCS control system end to perform re-denitrification on the denitrified flue gas; if the nitrogen oxide concentration in the denitrified flue gas does not meet the emission requirements but the ammonia concentration in the denitrified flue gas meets the emission requirements, the circulation system end determines the target ammonia injection amount based on the ammonia concentration and the nitrogen oxide concentration in the denitrified flue gas and then generates a second feedback instruction, so as to control the ammonia injection amount of the denitrification reaction end through the DCS control system end as the target ammonia injection amount to perform re-denitrification on the denitrified flue gas.

[0030] The present application provides a flue gas denitrification system and control method for a thermal power plant. The denitrification system integrates a host end, a DCS control system end, a denitrification reaction end, a flue gas outlet detection end and a circulation system end. In the denitrification reaction end, ammonia is used to react with the flue gas to be denitrified to generate denitrified flue gas, and the flow rate of the flue gas to be denitrified and the amount of ammonia sprayed are also collected; the flue gas outlet detection end detects the ammonia concentration and nitrogen oxide concentration in the denitrified flue gas, and the circulation system end detects the ammonia concentration or nitrogen oxide concentration in the denitrified flue gas based on the flow rate of the flue gas to be denitrified, the amount of ammonia sprayed, the ammonia concentration in the denitrified flue gas and the nitrogen oxide concentration. When the concentration of the substance does not meet the emission requirements, a feedback instruction is generated. The host end and the DCS control system end jointly control the ammonia injection amount of the denitrification reaction end. The ammonia injection amount of the denitrification reaction end or the flow rate of the flue gas to be denitrified is also assisted based on the feedback instruction to perform re-denitrification on the denitrification flue gas. In this case, by adjusting the ammonia injection amount of the denitrification reaction end, the nitrogen oxides in the flue gas to be denitrified can be better denitrified, avoiding excessive nitrogen oxide concentration or excessive ammonia escape rate, and solving the problems of excessive ammonia injection and insufficient ammonia injection in the existing denitrification system.

[0031] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0033] FIG1 is a block diagram of a flue gas denitrification system for a thermal power plant provided in an embodiment of the present application;

[0034] FIG2 is a block diagram of a denitration reaction end provided in an embodiment of the present application;

[0035] FIG3 is a block diagram of a smoke outlet detection terminal provided in an embodiment of the present application;

[0036] FIG4 is a block diagram of a circulation system provided in an embodiment of the present application;

[0037] FIG5 is a process flow chart of a flue gas denitrification system for a thermal power plant provided in an embodiment of the present application;

[0038] FIG6 is a flow chart of a control method for a flue gas denitrification system in a thermal power plant provided in an embodiment of the present application. DETAILED DESCRIPTION

[0039] Exemplary embodiments are described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numbers in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible implementations consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with certain aspects of the present invention, as detailed in the appended claims.

[0040] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined. It should also be understood that the term "and / or" used in this application refers to and includes any or all possible combinations of one or more associated listed items.

[0042] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0043] The present application proposes a flue gas denitrification system and a control method for a thermal power plant to solve the problems of excessive ammonia injection and insufficient ammonia injection in existing denitrification systems.

[0044] In the first embodiment, FIG1 is a block diagram of a flue gas denitrification system for a thermal power plant provided in an embodiment of the present application. In the present application, the flue gas denitrification system for a thermal power plant may be referred to as a denitrification system. As shown in FIG1 , the flue gas denitrification system for a thermal power plant includes a host end, a DCS control system end, a denitrification reaction end, a flue gas outlet detection end, and a circulation system end. The DCS control system end is simultaneously connected to the host end, the denitrification reaction end, the flue gas outlet detection end, and the circulation system end, and the circulation system end is connected to the denitrification reaction end and the flue gas outlet detection end. Among them, the host end and the DCS control system end are connected through signals, the DCS control system end is respectively connected to the denitrification reaction end, the flue gas outlet detection end, and the circulation system end through data signals, and the circulation system end is connected to the denitrification reaction end and the flue gas outlet detection end through signals.

[0045] In this embodiment, the denitrification reaction end is used to spray ammonia and utilize ammonia to react with the flue gas to be denitrified to generate denitrified flue gas, and is also used to collect the flow rate of the flue gas to be denitrified and the amount of ammonia sprayed.

[0046] FIG2 is a block diagram of the denitration reaction end provided in an embodiment of the present application.

[0047] In this embodiment, as shown in Figure 2, the denitrification reaction end includes an ammonia injection amount adjustment module, a reactor, a flue gas flow detection module, a first data transmission module and a first wireless signal module; the ammonia injection amount adjustment module is connected to the DCS control system end; the reactor includes an ammonia injection pipeline, a first flue gas inlet pipeline, a second flue gas inlet pipeline and a flue gas outlet pipeline; the ammonia injection amount adjustment module is installed on the outside of the ammonia injection pipeline, and the ammonia injection amount adjustment module is connected to the DCS control system end through a data signal; the first flue gas inlet pipeline transports the flue gas to be denitrified, and the flue gas to be denitrified is provided by the thermal power unit; the flue gas flow detection module is installed inside the first flue gas inlet pipeline; the ammonia injection amount adjustment module and the flue gas flow detection module are respectively connected to the first data transmission module, and the first data transmission module is connected to the circulation system end via the first wireless signal module, wherein the first wireless signal module and the circulation system end are connected through a data signal; the second flue gas inlet pipeline and the flue gas outlet pipeline are respectively connected to the circulation system end.

[0048] In this embodiment, the ammonia injection rate adjustment module utilizes an electrically controlled regulating valve. This module is connected to the DCS control system via data signals. This allows the DCS to easily adjust the opening of the electrically controlled regulating valve, facilitating the quantitative delivery of ammonia over a specified period of time and preventing waste caused by excessive ammonia delivery.

[0049] In this embodiment, the ammonia injection amount adjustment module is connected to the first data transmission module. Since the opening signal of the ammonia injection amount adjustment module corresponds to the ammonia injection amount, the opening signal sent by the ammonia injection amount adjustment module to the first data transmission module represents the corresponding ammonia injection amount.

[0050] In this embodiment, there can be multiple ammonia injection pipelines.

[0051] In this embodiment, the reactor is used to provide a reaction site for the circulation system end and ammonia gas.

[0052] In this embodiment, the flue gas flow detection module is used to detect the flow of the flue gas to be denitrified in the first flue gas inlet pipe. Therefore, the flue gas flow detection module detects the amount of flue gas delivered to the reactor each time, which facilitates the numerical calculation of the subsequent circulation system.

[0053] In this embodiment, the first data transmission module is used to transmit the detected flow rate of the flue gas to be denitrified and the amount of ammonia injection to the first wireless signal module.

[0054] In this embodiment, the first wireless signal module is used to send the data from the first data transmission module to the circulatory system end in the form of a wireless signal.

[0055] In this embodiment, the flue gas outlet detection end is used to detect the ammonia concentration and nitrogen oxide concentration in the denitrification flue gas.

[0056] FIG3 is a block diagram of a smoke outlet detection terminal provided in an embodiment of the present application.

[0057] In this embodiment, as shown in FIG3 , the flue gas outlet detection end includes an outlet nitrogen oxide concentration detection module (ie, outlet NO x concentration detection module), outlet ammonia concentration detection module, second data transmission module and second wireless signal module; outlet nitrogen oxide concentration detection module and outlet ammonia concentration detection module are both installed inside the flue gas outlet duct, outlet nitrogen oxide concentration detection module and outlet ammonia concentration detection module are respectively connected to the second data transmission module, the second data transmission module is connected to the circulation system end via the second wireless signal module, wherein the second wireless signal module is connected to the circulation system end via a wireless data signal. In this case, the outlet NOx detection module at the flue gas outlet is detected by the second wireless signal module. x The concentration detection module and the outlet ammonia concentration detection module detect the concentration of nitrogen oxides and ammonia in the denitrification flue gas, so as to avoid direct discharge of nitrogen oxides and ammonia after the concentration exceeds the standard, causing environmental pollution. By detecting the numerical values ​​of the concentration of nitrogen oxides and ammonia, it is convenient to cooperate with the subsequent circulation system end to perform numerical calculations.

[0058] In this embodiment, the outlet NO x The concentration detection module is used to detect the concentration of nitrogen oxides in the denitrification flue gas in the flue gas outlet pipe of the reactor.

[0059] In this embodiment, the outlet ammonia concentration detection module is used to detect the concentration of ammonia in the denitrification flue gas in the flue gas outlet pipe of the reactor.

[0060] In this embodiment, the second data transmission module is used to transmit the detected concentration of nitrogen oxides in the denitrification flue gas and the detected concentration of ammonia in the denitrification flue gas to the second wireless signal module.

[0061] In this embodiment, the second wireless signal module is used to send the concentration of nitrogen oxides and the concentration of ammonia in the denitrification flue gas transmitted by the second data transmission module to the DCS control system end and the circulation system end in the form of wireless signals.

[0062] In this embodiment, the circulation system end is used to generate a feedback instruction based on the flow rate of the flue gas to be denitrified, the amount of ammonia sprayed, the ammonia concentration and the nitrogen oxide concentration in the denitrified flue gas when the ammonia concentration or the nitrogen oxide concentration in the denitrified flue gas does not meet the emission requirements.

[0063] FIG4 is a block diagram of a circulation system provided in an embodiment of the present application.

[0064] As shown in Figure 4, the circulation system end includes a third wireless signal module, a data receiving module, a data acquisition module, a data online calculation module, a data processing module, a third data transmission module and a storage; the third wireless signal module is connected to the second wireless signal module and the first wireless signal module at the same time, and the third wireless signal module is also connected to the DCS control system end via the data receiving module, the data acquisition module, the data online calculation module, the data processing module and the third data transmission module. The storage includes a flue gas inlet, a first flue gas outlet and a second flue gas outlet. The flue gas inlet is connected to the flue gas outlet pipe of the denitrification reaction end, and the first flue gas outlet is connected to the second flue gas inlet pipe of the denitrification reaction end.

[0065] In this embodiment, the third wireless signal module is signal-connected to the second wireless signal module and the first wireless signal module. The third wireless signal module is signal-connected to the data acquisition module via the data receiving module. The data acquisition module is signal-connected to the online data calculation module via data signals, and the online data calculation module is signal-connected to the data processing module via data signals. The data processing module is signal-connected to the DCS control system via the third data transmission module.

[0066] In this embodiment, the first wireless signal module and the second wireless signal module are both wireless signal transmitters, and the third wireless signal module is a wireless signal receiver.

[0067] In this embodiment, the third wireless signal module is used to convert the wireless signals from the first and second wireless signal modules and transmit them to the data receiving module. The wireless signals from the first wireless signal module include wireless signals indicating the flow rate of the flue gas to be denitrified and the amount of ammonia injected, while the wireless signals from the second wireless signal module include wireless signals indicating the ammonia concentration and nitrogen oxide concentration in the denitrified flue gas.

[0068] In this embodiment, the data receiving module sends the data from the third wireless signal module to the data acquisition module.

[0069] In this embodiment, the data acquisition module collects and integrates the data from the data receiving module and then transfers the data to the data online calculation module.

[0070] In this embodiment, as shown in FIG4 , the data online calculation module includes a feedforward nitrogen oxide input compensation logic module (ie, feedforward NO x Input compensation logic module), feedforward ammonia injection compensation logic module and feedforward nitrogen oxide average value logic module (i.e. feedforward NO x Average value logic module). Feedforward NO x Input compensation logic module, feedforward ammonia injection compensation logic module and feedforward NO x The average value logic module is connected to the data acquisition module signal, feedforward NO x Input compensation logic module, feedforward ammonia injection compensation logic module and feedforward NO x The average value logic module is respectively connected with the data signal between the data processing modules.

[0071] In this embodiment, when it is detected that the concentration of nitrogen oxides in the denitrification flue gas reaches the standard value, and the concentration of ammonia in the denitrification flue gas exceeds the standard, the feedforward NO x The input compensation logic module performs NO x Input compensation calculation; feedforward NO x The average value logic module is used to obtain a certain amount of nitrogen oxide concentration in the flue gas to be denitrified based on the amount of ammonia injected quantitatively at the denitrification reaction end and the flue gas flow value detected by the flue gas flow detection module. When the concentration of nitrogen oxides in the denitrified flue gas is detected to be higher than the standard value, and the concentration of ammonia is within the standard range, the feedforward ammonia injection amount compensation logic module will calculate the nitrogen oxide concentration in the flue gas to be denitrified based on the outlet NO x The concentration value of nitrogen oxides detected by the concentration detection module and the concentration value of ammonia detected by the outlet ammonia concentration detection module are used to perform ammonia input compensation calculation at the flue gas outlet detection end.

[0072] In this embodiment, the data processing module integrates the data output by the data online calculation module to obtain the first feedback instruction or the second feedback instruction and sends it to the third data delivery module.

[0073] In this embodiment, the third data delivery module is used to transfer the first feedback instruction or the second feedback instruction from the data processing module to the DCS control system end.

[0074] In this embodiment, the storage is a gas storage tank, and the storage is used to store the denitrification flue gas discharged from the reactor.

[0075] In this embodiment, the reservoir is connected to the reactor via a pipeline. Specifically, the flue gas inlet of the reservoir is connected to the flue gas outlet of the reactor at the denitration reaction end via a sealed pipeline. The first flue gas outlet of the reservoir is connected to the second flue gas inlet of the reactor at the denitration reaction end via a pipeline.

[0076] As shown in Figure 4, the circulation system also includes a heating module, which is electrically connected to the DCS control system.

[0077] Specifically, the heating module includes a heater and a temperature sensor (see Figure 4). The heater is installed around the inner wall of the storage, and the temperature sensor is installed on the top of the inner cavity of the storage. The heater and the temperature sensor are both connected to the DCS control system end (see Figure 4), wherein the heater and the temperature sensor are both connected to the DCS control system end electrical signal. In this case, the internal temperature of the storage is heated by the heater, and the temperature is detected by the temperature sensor, which conveniently and effectively provides the appropriate temperature, avoiding the temperature of the denitrification flue gas from dropping too fast during the mobile transportation process, making it impossible for the ammonia to undergo subsequent denitrification.

[0078] In this embodiment, the heater is controlled by the DCS control system.

[0079] In this embodiment, the entire circulation system is convenient for collecting and integrating data of the entire system for feedback. When the concentration of nitrogen oxides reaches the standard value (that is, the concentration of nitrogen oxides in the denitrification flue gas meets the emission requirements), and the concentration of ammonia exceeds the standard (that is, the concentration of ammonia in the denitrification flue gas does not meet the emission requirements) or the concentration of nitrogen oxides is higher than the standard value, and the concentration of ammonia is within the standard range, the denitrification flue gas in the storage is returned to the reactor. By inputting a certain amount of flue gas, it is convenient to consume excess ammonia or transport a certain amount of ammonia to facilitate re-denitrification of high-concentration nitrogen oxides so that their concentration meets the standard value, which is convenient for emission and the entire system can work effectively.

[0080] In this embodiment, the host side is used to generate a power generation load instruction.

[0081] In this embodiment, the DCS control system end is used to control the ammonia injection amount of the denitrification reaction end based on the power generation load instruction, and also to assist in controlling the ammonia injection amount of the denitrification reaction end or the flow rate of the flue gas to be denitrified based on the feedback instruction to perform re-denitrification on the denitrified flue gas, so that the ammonia concentration and nitrogen oxide concentration in the denitrification flue gas meet the emission requirements.

[0082] In this embodiment, the DCS control system end is connected to the circulation system end, the denitrification reaction end, and the flue gas outlet detection end through programming connection, so that the host end can operate the entire system in combination with the DCS control system end.

[0083] In this embodiment, ammonia is sprayed through the denitrification reaction end and the flue gas to be denitrified is transported for reaction, nitrogen oxides and ammonia in the flue gas are detected through the flue gas outlet detection end, and after data integration and numerical calculation through the circulation system end, the flue gas is returned to the reactor at the denitrification reaction end for secondary denitrification treatment, so as to facilitate the effective operation of the entire system.

[0084] FIG5 is a process flow chart of a flue gas denitrification system for a thermal power plant provided in an embodiment of the present application.

[0085] Specifically, with reference to FIG5 , the specific denitrification process of the flue gas denitrification system of a thermal power plant is as follows:

[0086] Open the valve K1 on the outside of the first flue gas inlet pipe A1 of the reactor, and the flue gas to be denitrified enters the reactor through the flue gas inlet of the first flue gas inlet pipe A1, and the flue gas flow detection module performs flue gas flow value detection and record and feeds back to the circulation system end, open the valve K2 of the ammonia injection pipe B of the reactor, and initially control the opening of the ammonia injection amount adjustment module (such as the electric control regulating valve) set by the startup system through the DCS control system end to facilitate ammonia injection, and then ammonia reacts with nitrogen oxides in the flue gas to be denitrified for the first time to denitrify and obtain denitrified flue gas, and the denitrified flue gas then enters the flue gas outlet pipe C of the reactor and passes through the outlet NO x The concentration detection module and the outlet ammonia concentration detection module detect the nitrogen oxides and ammonia concentrations and feed them back to the circulation system end. At the same time, the valve K5 on the pipe M at the flue gas inlet of the storage is opened, and the pipe M is connected to the internal outlet NO x The concentration detection module and the outlet ammonia concentration detection module are connected to the flue gas pipe C, and then the denitrified flue gas enters the storage device. When the concentration of nitrogen oxides in the denitrified flue gas reaches the standard value and the concentration of ammonia in the denitrified flue gas exceeds the standard, the NO required for this concentration of ammonia is calculated through the circulation system end. xAfter the input amount is compensated and the concentration of nitrogen oxides in a certain amount of flue gas is calculated, the valve K3 on the pipe N at the first flue gas outlet of the storage device and the exhaust fan are opened to discharge the initially obtained denitrified flue gas into the reactor through the second flue gas inlet pipe A2, and a certain amount of flue gas to be denitrified is input into the reactor through the first flue gas inlet pipe A1 at the flue gas inlet to consume the excess ammonia that escapes, and then the flue gas is discharged through the outlet NO x The concentration detection module and the outlet ammonia concentration detection module perform detection until the concentrations of nitrogen oxides and ammonia are both within the standard range. After being discharged to the storage again, the final flue gas is discharged by opening the valve K4 on the outside of the pipe P at the second flue gas outlet of the storage; when it is detected that the concentration of nitrogen oxides in the denitrification flue gas is higher than the standard value and the concentration of ammonia is within the standard range, the ammonia input compensation required for this concentration of nitrogen oxides is calculated through the circulation system end. After repeating the above operation to send the denitrification flue gas to the reactor, the opening of the ammonia injection amount adjustment module, which is opened as an electric control regulating valve, is automatically adjusted by the DCS control system end to facilitate the quantitative discharge of ammonia from the ammonia injection pipeline to the reactor, and facilitate the secondary denitrification treatment of nitrogen oxides in the denitrification flue gas. When its concentration reaches the standard, it is discharged through the pipe P.

[0087] The following are method embodiments of the present application. For details not disclosed in the method embodiments of the present application, please refer to the system embodiments of the present application. The method embodiments of the present application provide a control method for a flue gas denitrification system in a thermal power plant. This control method utilizes the flue gas denitrification system of the thermal power plant described in the system embodiments. The control method for a flue gas denitrification system in a thermal power plant described in the present application may be referred to as simply the control method.

[0088] FIG6 is a flow chart of a control method for a flue gas denitrification system in a thermal power plant provided in an embodiment of the present application.

[0089] As shown in FIG6 , the control method of the flue gas denitrification system of the thermal power plant includes:

[0090] Step S101: When the host terminal issues a power generation load instruction, the flue gas to be denitrated generated by the thermal power unit enters the reactor of the denitrification reaction end, and the denitrification reaction end sends the collected flue gas flow to the circulation system end;

[0091] Step S102: When the DCS control system receives the power generation load instruction sent by the host, it controls the ammonia injection amount of the denitration reaction end to be the initial injection amount, and the denitration reaction end sends the ammonia injection amount to the circulation system end in real time;

[0092] Step S103: In the denitration reaction end, ammonia reacts with the flue gas to be denitrated to generate denitrated flue gas. The flue gas outlet detection end detects the ammonia concentration and nitrogen oxide concentration in the denitrated flue gas and sends the result to the circulation system end.

[0093] Step S104: The circulation system generates a feedback instruction based on the flow rate of the flue gas to be denitrated, the amount of ammonia injected, the ammonia concentration and the nitrogen oxide concentration in the denitrated flue gas when the ammonia concentration or the nitrogen oxide concentration in the denitrated flue gas does not meet the emission requirements;

[0094] In step S105, the DCS control system side assists in controlling the ammonia injection amount of the denitrification reaction end or the flow rate of the flue gas to be denitrified based on the feedback instruction to perform re-denitrification on the denitrified flue gas so that the ammonia concentration and nitrogen oxide concentration in the denitrified flue gas meet the emission requirements.

[0095] In step S104, the feedback instruction includes a first feedback instruction and a second feedback instruction. When the ammonia concentration or the nitrogen oxide concentration in the denitrification flue gas does not meet the emission requirements based on the flow rate of the flue gas to be denitrified, the amount of ammonia sprayed, the ammonia concentration in the denitrification flue gas, and the nitrogen oxide concentration, a feedback instruction is generated, including: if the nitrogen oxide concentration in the denitrification flue gas meets the emission requirements but the ammonia concentration in the denitrification flue gas does not meet the emission requirements, the circulation system end determines the target flow rate of the flue gas to be denitrified based on the flow rate of the flue gas to be denitrified, the amount of ammonia sprayed, and the ammonia concentration in the denitrification flue gas, and then generates a first feedback instruction, so as to control the flue gas to be denitrified with the target flow rate to enter the reactor through the DCS control system end to perform re-denitrification on the denitrification flue gas; if the nitrogen oxide concentration in the denitrification flue gas does not meet the emission requirements but the ammonia concentration in the denitrification flue gas meets the emission requirements, the circulation system end determines the target ammonia spraying amount based on the ammonia concentration and the nitrogen oxide concentration in the denitrification flue gas, and then generates a second feedback instruction, so as to control the ammonia spraying amount of the denitrification reaction end through the DCS control system end as the target ammonia spraying amount to perform re-denitrification on the denitrification flue gas.

[0096] In some embodiments, the specific method of controlling the flue gas denitrification system of a thermal power plant includes:

[0097] Step a: First, through the signal connection between the host end and the DCS control system end, program and connect all the lines that need signal or circuit connection between the DCS control system end, the circulation system end, the denitrification reaction end, and the flue gas outlet detection end;

[0098] Step b, when the host end issues a power generation load instruction, the boiler equipment of the thermal power unit quickly responds to the fuel quantity, oxygen quantity and air volume, and the flue gas generated by its power generation work (i.e., the flue gas to be denitrified) finally enters the reactor through the first flue gas inlet pipe outside the reactor. At the same time, the flue gas flow detection module detects the flue gas flow entering the reactor, and at the same time transmits this information (i.e., the flue gas flow to be denitrified) to the first data transmission module. The first data transmission module transmits this information to the circulation system end through the first wireless signal module. At this time, the DCS control system end automatically opens the initial system-set opening of the ammonia injection amount adjustment module of the electric control regulating valve, so as to facilitate the quantitative discharge of ammonia from the ammonia injection pipe to the reactor (i.e., discharge of ammonia according to the initial injection amount), and sprays it through the nozzle on the ammonia injection pipe to mix and react with the flue gas to be denitrified entering the reactor, so as to achieve denitrification of nitrogen oxides in the flue gas;

[0099] Step c: After the denitrification of nitrogen oxides in the flue gas to be denitrated in step b is completed, the denitrified flue gas in the reactor enters the flue gas outlet pipe and passes through the outlet NO x The concentration detection module and the outlet ammonia concentration detection module detect the concentration of nitrogen oxides and ammonia in the denitrification flue gas, and transmit this information to the second data transmission module, which transmits this information to the circulation system end through the second wireless signal module;

[0100] Step d: When it is detected that the concentration of nitrogen oxides in the denitrification flue gas reaches the standard value and the concentration of ammonia in the denitrification flue gas exceeds the standard, the third wireless signal module at the circulation system end receives the signal and transmits the information to the data receiving module, and the data receiving module transmits the information to the data acquisition module, which performs data acquisition and integration, and calculates the NOx concentration through the feedforward of the data online calculation module. x The input compensation logic module performs NO x Input compensation calculation; In addition, the amount of ammonia injected quantitatively at the denitrification reaction end and the flue gas flow rate value detected by the flue gas flow detection module are fed back. This information is also received by the third wireless signal module, and after the data is transmitted by the data receiving module and the data acquisition module, this information is fed back to the feedforward NO xThe average value logic module obtains the nitrogen oxide concentration in a certain amount of flue gas, thereby obtaining the target flow rate of the flue gas to be denitrified, and transmits this information to the data processing module for data integration processing to obtain the first feedback instruction, and then feeds this information back to the DCS control system end through the third data transmission module. At the same time, the DCS control system end turns on the heater and temperature sensor of the heating module, and uses the heater to heat the inner cavity temperature of the storage to the set temperature to prevent the flue gas from dropping too quickly during the movement and transportation process, causing the ammonia to be unable to undergo subsequent denitrification. The temperature sensor monitors the inner cavity temperature of the storage. When it is heated to the set temperature, the temperature sensor detects this information and transmits it to the DCS control system end. The DCS control system end automatically turns off the heater, discharges the primary denitrified flue gas into the reactor through the pipeline, and inputs a certain amount of flue gas to be denitrified into the reactor through the first flue gas inlet pipe of the flue gas inlet. The nitrogen oxide content in the flue gas to be denitrified reacts with the ammonia in the primary denitrified flue gas, and consumes the excess escaping ammonia. After the secondary denitrification treatment is completed, the flue gas is discharged through the outlet NO x The concentration detection module and the outlet ammonia concentration detection module perform detection. When the detected concentrations of nitrogen oxides and ammonia are both within the standard range, they are discharged to the storage device again and then discharged through the storage device.

[0101] Step e: When the concentration of nitrogen oxides in the denitrification flue gas is detected to be higher than the standard value, and the concentration of ammonia is within the standard range, the third wireless signal module at the circulation system end receives the signal and transmits the information to the data receiving module. The data receiving module transmits the information to the data acquisition module, and the data acquisition module performs data acquisition and integration. The feedforward ammonia injection amount compensation logic module of the data online calculation module calculates the output of the NOx at the outlet. xThe concentration value of nitrogen oxides detected by the concentration detection module and the concentration value of ammonia detected by the outlet ammonia concentration detection module are used to perform ammonia input compensation calculation at the flue gas outlet detection end, thereby obtaining the target ammonia injection amount, and transmitting this information to the data processing module for data integration processing to obtain a second feedback instruction, and then feeding this information back to the DCS control system end through the third data transmission module. At the same time, the DCS control system end turns on the heater and temperature sensor of the heating module, and heats the inner cavity temperature of the storage to the set temperature through the heater to avoid the flue gas temperature dropping too fast during the mobile transportation process, causing the ammonia to be unable to undergo subsequent denitrification, and the temperature sensor is used to control the temperature of the storage. The inner cavity temperature is monitored. When heated to the set temperature, this information is detected by the temperature sensor and transmitted to the DCS control system end. The DCS control system end automatically turns off the heater and discharges the flue gas of the primary denitrification into the reactor through the pipeline. The DCS control system end automatically adjusts the opening of the ammonia injection amount adjustment module of the electric control regulating valve to facilitate the quantitative emission of ammonia from the ammonia injection pipeline to the reactor (i.e., ammonia is emitted according to the target ammonia injection amount). It is sprayed out through the nozzle on the ammonia injection pipeline and mixed with the flue gas of the primary denitrification entering the reactor to denitrify the nitrogen oxides in the flue gas of the primary denitrification. After the secondary denitrification is completed, the flue gas is discharged through the outlet NO x The concentration detection module and the outlet ammonia concentration detection module perform detection. When the detected concentrations of nitrogen oxides and ammonia are both within the standard range, they are discharged to the storage device again and then discharged through the storage device.

[0102] Step f: When encountering the situations in the above steps d and e, a power generation load instruction is issued through the host end, and the DCS control system end readjusts the opening of the ammonia injection amount adjustment module at the denitrification reaction end according to the conditions of the current power generation load instruction, so as to better denitrify a certain amount of nitrogen oxides in the flue gas, thereby avoiding excessive nitrogen oxide concentration or excessive ammonia escape rate. When different power generation load instructions appear subsequently, excessive nitrogen oxide concentration or excessive ammonia escape rate can be avoided by circulating the flue gas.

[0103] It should be noted that the aforementioned explanation of the embodiment of the flue gas denitrification system for a thermal power plant is also applicable to the control method of the flue gas denitrification system for a thermal power plant in this embodiment, and will not be repeated here.

[0104] The serial numbers of the above embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0105] In the embodiment of the present application, the flue gas denitrification system and control method of the thermal power plant are integrated with the host end, the DCS control system end, the denitrification reaction end, the flue gas outlet detection end and the circulation system end. The denitrification reaction end uses ammonia to react with the flue gas to be denitrified to generate denitrified flue gas, and also collects the flow rate of the flue gas to be denitrified and the amount of ammonia sprayed; the flue gas outlet detection end detects the ammonia concentration and the nitrogen oxide concentration in the denitrified flue gas, and the circulation system end detects the ammonia concentration or nitrogen oxide concentration in the denitrified flue gas based on the flow rate of the flue gas to be denitrified, the amount of ammonia sprayed, the ammonia concentration in the denitrified flue gas and the nitrogen oxide concentration. When the concentration of nitrogen oxides does not meet the emission requirements, a feedback instruction is generated. The host end and the DCS control system end jointly control the ammonia injection amount of the denitrification reaction end. The ammonia injection amount of the denitrification reaction end or the flow rate of the flue gas to be denitrified is also assisted based on the feedback instruction to perform re-denitrification on the denitrified flue gas. In this case, by adjusting the ammonia injection amount of the denitrification reaction end, the nitrogen oxides in the flue gas to be denitrified can be better denitrified, avoiding excessive nitrogen oxide concentration or excessive ammonia escape rate, and solving the problems of excessive ammonia injection and insufficient ammonia injection in the existing denitrification system.

[0106] Specifically, the beneficial effects of the present application are: adjusting the ammonia injection opening at the denitrification reaction end and detecting and recording the flue gas flow, and x The concentration detection module and the outlet ammonia concentration detection module detect whether the nitrogen oxides or ammonia concentration in the flue gas discharged from the reactor exceeds the standard. When the ammonia concentration exceeds the standard, the flue gas of the initial denitrification is stored through the circulation system end and re-transported to the reactor and through data integration and numerical calculation, and by inputting a certain amount of flue gas to be denitrified and reacting with the ammonia in the flue gas of the initial denitrification, the ammonia with an excessive concentration is consumed, so that the ammonia can be recycled once when the initial escape rate is large, so as to effectively reduce its escape rate, avoid waste, and effectively improve the use effect. When the nitrogen oxide concentration exceeds the standard, the flue gas of the initial denitrification is stored through the circulation system end and re-transported to the reactor and through data Integration and numerical calculation, by adjusting the opening of the ammonia injection amount adjustment module (electrically controlled regulating valve), a certain amount of ammonia is input within a certain period of time, so as to facilitate the secondary denitrification of high-concentration nitrogen oxides in the flue gas of the initial denitrification, avoid excessive nitrogen oxide concentration, cause emission pollution, and facilitate this system to effectively improve the utilization rate of ammonia and avoid direct emission of high-concentration nitrogen oxides. In addition, through the host end, a command is issued, and the DCS control system end readjusts the opening of the ammonia injection amount adjustment module at the denitrification reaction end according to the conditions of the current power generation load command, so that the ammonia injection amount can adapt to the concentration of nitrogen oxides in the current certain amount of flue gas flow, effectively improving the avoidance of excessive ammonia injection resulting in increased escape rate and NO in the emitted flue gas. xIf the concentration is too high and the power generation load instruction is adjusted, the flue gas can be recirculated and denitrified through this system, which is convenient for use. Compared with existing technologies, the system logic design of this application is reasonable and practical. It is convenient to recirculate and reuse excess ammonia after it escapes, reducing its escape rate, and at the same time, it can control the emission concentration of nitrogen oxides within the standard value range, which is convenient for protecting the ecological environment while improving economic benefits.

[0107] The accompanying drawings illustrate schematic diagrams of the structures of the embodiments disclosed herein. These figures are not drawn to scale; for the purpose of clarity, some details are exaggerated and some details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions as needed.

[0108] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this application can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions disclosed in this application can be achieved. This application is not limited here.

[0109] The above specific embodiments do not constitute a limitation on the scope of protection of this application. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application shall be included within the scope of protection of this application.

Claims

1. A flue gas denitrification system for a thermal power plant, characterized in that: It includes a host end, a DCS control system end, a denitration reaction end, a flue gas outlet detection end and a circulation system end, wherein the DCS control system end is connected to the host end, the denitration reaction end, the flue gas outlet detection end and the circulation system end at the same time, and the circulation system end is connected to the denitration reaction end and the flue gas outlet detection end; The host side is used to generate a power generation load instruction; The denitration reaction end is used to spray ammonia and utilize ammonia to react with the flue gas to be denitrated to generate denitrated flue gas, and is also used to collect the flow rate of the flue gas to be denitrated and the amount of ammonia sprayed; The flue gas outlet detection end is used to detect the ammonia concentration and the nitrogen oxide concentration in the denitrification flue gas; The circulation system end is used to generate a feedback instruction based on the flow rate of the flue gas to be denitrated, the amount of ammonia injection, the ammonia concentration and the nitrogen oxide concentration in the denitrated flue gas when the ammonia concentration or the nitrogen oxide concentration in the denitrated flue gas does not meet the emission requirements; The DCS control system end is used to control the ammonia injection amount of the denitrification reaction end based on the power generation load instruction, and also to assist in controlling the ammonia injection amount of the denitrification reaction end or the flow rate of the flue gas to be denitrified based on the feedback instruction to perform re-denitrification on the denitrification flue gas, so that the ammonia concentration and nitrogen oxide concentration in the denitrification flue gas meet the emission requirements.

2. The flue gas denitrification system of a thermal power plant according to claim 1, characterized in that: The denitrification reaction end includes an ammonia injection amount adjustment module, a reactor, a flue gas flow detection module, a first data transmission module and a first wireless signal module. The ammonia injection amount adjustment module is connected to the DCS control system end. The reactor includes an ammonia injection pipeline, a first flue gas inlet pipeline, a second flue gas inlet pipeline and a flue gas outlet pipeline. The ammonia injection amount adjustment module is installed on the outside of the ammonia injection pipeline. The first flue gas inlet pipeline transports the flue gas to be denitrified. The flue gas flow detection module is installed inside the first flue gas inlet pipeline. The ammonia injection amount adjustment module and the flue gas flow detection module are respectively connected to the first data transmission module. The first data transmission module is connected to the circulation system end via the first wireless signal module. The second flue gas inlet pipeline and the flue gas outlet pipeline are respectively connected to the circulation system end.

3. The flue gas denitrification system of a thermal power plant according to claim 2, characterized in that: The ammonia injection amount regulating module adopts an electric control regulating valve.

4. The flue gas denitrification system of a thermal power plant according to claim 2, characterized in that: The flue gas outlet detection end includes an outlet nitrogen oxide concentration detection module, an outlet ammonia concentration detection module, a second data transmission module and a second wireless signal module. The outlet nitrogen oxide concentration detection module and the outlet ammonia concentration detection module are both installed inside the flue gas outlet pipe. The outlet nitrogen oxide concentration detection module and the outlet ammonia concentration detection module are respectively connected to the second data transmission module, and the second data transmission module is connected to the circulation system end via the second wireless signal module.

5. The flue gas denitrification system of a thermal power plant according to claim 4, characterized in that: The circulation system end includes a third wireless signal module, a data receiving module, a data acquisition module, a data online calculation module, a data processing module, a third data transmission module and a storage device. The third wireless signal module is connected to the second wireless signal module and the first wireless signal module at the same time. The third wireless signal module is also connected to the DCS control system end via the data receiving module, the data acquisition module, the data online calculation module, the data processing module and the third data transmission module. The storage device includes a smoke inlet, a first smoke outlet and a second smoke outlet. The smoke inlet is connected to the smoke outlet pipe of the denitration reaction end, and the first smoke outlet is connected to the second smoke inlet pipe of the denitration reaction end.

6. The flue gas denitrification system of a thermal power plant according to claim 5, characterized in that: The first wireless signal module and the second wireless signal module are both wireless signal transmitters, and the third wireless signal module is a wireless signal receiver.

7. The flue gas denitrification system of a thermal power plant according to claim 5, characterized in that: The data online calculation module includes a feedforward nitrogen oxide input compensation logic module, a feedforward ammonia injection compensation logic module and a feedforward nitrogen oxide average value logic module.

8. The flue gas denitrification system of a thermal power plant according to claim 5, characterized in that: The circulation system end also includes a heating module, which includes a heater and a temperature sensor. The heater is installed around the inner wall of the storage, and the temperature sensor is installed on the top of the inner cavity of the storage. Both the heater and the temperature sensor are connected to the DCS control system end.

9. A control method for a flue gas denitration system in a thermal power plant according to any one of claims 1 to 8, characterized in that: include: When the host end issues a power generation load instruction, the flue gas to be denitrated generated by the operation of the thermal power unit enters the reactor at the denitration reaction end, and the denitration reaction end sends the collected flow of the flue gas to be denitrated to the circulation system end; When the DCS control system receives the power generation load instruction sent by the host end, the ammonia spraying amount of the denitration reaction end is controlled to be the initial spraying amount, and the denitration reaction end sends the ammonia spraying amount to the circulation system end in real time; In the denitration reaction end, ammonia reacts with the flue gas to be denitrated to generate denitrated flue gas, and the flue gas outlet detection end detects the ammonia concentration and nitrogen oxide concentration in the denitrated flue gas and sends them to the circulation system end; The circulation system end generates a feedback instruction based on the flow rate of the flue gas to be denitrated, the amount of ammonia sprayed, the ammonia concentration and the nitrogen oxide concentration in the denitrated flue gas when the ammonia concentration or the nitrogen oxide concentration in the denitrated flue gas does not meet the emission requirements; The DCS control system side assists in controlling the ammonia injection amount of the denitrification reaction end or the flow rate of the flue gas to be denitrified based on the feedback instruction to perform re-denitrification on the denitrified flue gas so that the ammonia concentration and the nitrogen oxide concentration in the denitrified flue gas meet the emission requirements.

10. The control method of the flue gas denitrification system of a thermal power plant according to claim 9, characterized in that: The feedback instruction includes a first feedback instruction and a second feedback instruction, and the feedback instruction is generated based on the flow rate of the flue gas to be denitrated, the amount of ammonia injection, the ammonia concentration and the nitrogen oxide concentration in the denitrated flue gas when the ammonia concentration or the nitrogen oxide concentration in the denitrated flue gas does not meet the emission requirements, including: If the nitrogen oxide concentration in the denitrification flue gas meets the emission requirements but the ammonia concentration in the denitrification flue gas does not meet the emission requirements, the circulation system end determines the target flow rate of the denitrification flue gas based on the flow rate of the denitrification flue gas, the ammonia injection amount and the ammonia concentration in the denitrification flue gas, and then generates a first feedback instruction, so as to control the denitrification flue gas of the target flow rate to enter the reactor through the DCS control system end to perform denitrification on the denitrification flue gas again; If the nitrogen oxide concentration in the denitrification flue gas does not meet the emission requirements but the ammonia concentration in the denitrification flue gas meets the emission requirements, the circulation system end determines the target ammonia injection amount based on the ammonia concentration and the nitrogen oxide concentration in the denitrification flue gas and then generates a second feedback instruction, so as to control the ammonia injection amount of the denitrification reaction end through the DCS control system end as the target ammonia injection amount to perform denitrification on the denitrification flue gas again.

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