Method and system for monitoring scr ammonia slip rate

Abstract

The application discloses a kind of monitoring method and system of SCR ammonia escape rate, can improve denitration efficiency while reducing ammonia escape amount, wherein method includes based on the ammonia gas real-time detection concentration at the outlet of each ammonia injection pipe and the ammonia gas concentration required theoretically, obtain the ammonia injection amount theoretical concentration difference of each ammonia injection pipe;Based on the ammonia gas real-time detection concentration at the outlet of each ammonia injection pipe and the average ammonia gas concentration at the outlet of multiple ammonia injection pipes, obtain the ammonia injection amount actual concentration difference of each ammonia injection pipe;The difference of ammonia injection amount actual concentration difference and ammonia injection amount theoretical concentration difference of each ammonia injection pipe is obtained;If the difference is greater than preset ammonia escape concentration, the ammonia injection amount of corresponding ammonia injection pipe is reduced;If the difference is negative, the ammonia injection amount of corresponding ammonia injection pipe is increased;The application can obtain the real-time flow of input ammonia gas, the real-time value of hydroxide at flue gas inlet, online detection, real-time feedback, real-time adjustment, accurately control the ammonia gas flow injected, effectively reduce ammonia escape amount, reduce environmental pollution.

Description

Technical Field

[0001] This application relates to the technical field of flue gas treatment, and in particular to a method and system for monitoring the ammonia slip rate of an SCR system. Background Technology

[0002] SCR (Selective Catalytic Reduction) is increasingly being used in flue gas denitrification. SCR denitrification efficiency generally reaches over 90%, and ammonia or urea are mostly used as denitrification aids. Ammonia water as an absorbent has advantages such as low cost, high absorption efficiency, low regeneration energy consumption, good by-product resource utilization, and no corrosion problems. However, due to the high volatility of ammonia, ammonia slip has limited its development. Currently, the control of ammonia injection mainly adopts a fixed ammonia-to-nitrogen molar ratio. However, in reality, the ammonia-to-nitrogen ratio is non-uniform. During the denitrification process, the ammonia injected into the reactor cannot completely react with NOx, leading to changes in the nitrogen oxide concentration at the reactor outlet. Some unreacted ammonia also remains, causing a significant increase in ammonia slip and resulting in secondary pollution. How to control ammonia slip has become an urgent problem to be solved in SCR denitrification technology. Summary of the Invention

[0003] In order to improve denitrification efficiency while reducing ammonia slip, this application provides a method and system for monitoring SCR ammonia slip rate, which can realize real-time detection and real-time adjustment to ensure that the ammonia gas injected into the reactor during the denitrification process can fully react with hydroxide.

[0004] The first aspect of this application provides a method for monitoring SCR ammonia slip rate, which adopts the following technical solution:

[0005] A method for monitoring ammonia slip rate in SCR (Self-Containing Radiometer) systems, comprising the following steps:

[0006] Based on the real-time detected ammonia concentration at the outlet of each ammonia injection pipe and the theoretically required ammonia concentration, the theoretical concentration difference of the ammonia injection volume of each ammonia injection pipe is obtained.

[0007] Based on the real-time ammonia concentration detected at the outlet of each ammonia injection pipe and the average ammonia concentration at the outlets of multiple ammonia injection pipes, the actual concentration difference of ammonia injection amount in each ammonia injection pipe is obtained.

[0008] Obtain the difference between the actual concentration difference of ammonia injected into each ammonia injection pipe and the theoretical concentration difference of ammonia injected into each ammonia injection pipe;

[0009] If the difference is greater than the preset ammonia escape concentration, the ammonia injection rate of the corresponding ammonia injection pipe is reduced; if the difference is negative, the ammonia injection rate of the corresponding ammonia injection pipe is increased.

[0010] By adopting the above technical solution, the real-time flow rate of ammonia at the inlet of each ammonia injection pipe can be fed back in a timely and accurate manner, as can the real-time value of hydroxide at the inlet of the SCR denitrification unit. Furthermore, the required amount of ammonia can be quickly obtained, and the ammonia flow rate can be adjusted in real time based on the difference, thereby precisely controlling the injected ammonia flow rate, reducing ammonia escape, and minimizing environmental pollution.

[0011] Preferably, the method for obtaining the theoretically required ammonia concentration is as follows:

[0012] Based on the real-time detection of nitrogen oxide concentration at the flue gas inlet, the theoretical nitrogen oxide concentration at the outlet of each ammonia injection pipe is obtained; the ammonia concentration at the outlet of each ammonia injection pipe obtained according to the denitrification reaction formula is the theoretically required ammonia concentration.

[0013] By adopting the above technical solution, the real-time concentration of nitrogen oxides at the flue gas inlet is obtained. Unlike the existing method of obtaining the ammonia injection amount based on a fixed ammonia-nitrogen molar ratio, this method has higher detection accuracy and makes the overall ammonia injection amount control more precise.

[0014] Preferably, the preset ammonia escape concentration is 3 ppm.

[0015] By adopting the above technical solutions, the conversion efficiency of SCR catalysts can be improved, and air pollution can be reduced.

[0016] The second aspect of this application provides a monitoring system for SCR ammonia slip rate, which adopts the following technical solution:

[0017] A monitoring system for SCR ammonia slip rate includes a central control center, a main monitoring system, and multiple sub-monitoring systems, wherein the main monitoring system and multiple monitoring devices are all signal-connected to the central control center.

[0018] The main monitoring system is used to monitor the concentration of nitrogen oxides at the flue gas inlet in real time.

[0019] Each of the aforementioned sub-monitoring systems is respectively set up with a corresponding ammonia injection pipe to monitor the ammonia concentration at the outlet of the corresponding ammonia injection pipe in real time;

[0020] In operation, the central control center adjusts the flow rate of the corresponding ammonia injection pipe in real time based on the obtained nitrogen oxide concentration at the flue gas inlet and ammonia concentration at the ammonia injection pipe outlet.

[0021] By adopting the above technical solution, the flue gas velocity distribution at the ammonia injection point of the ammonia injection pipe and the concentration distribution of nitrogen oxides in the inlet flue gas can be obtained in real time. The denitrification efficiency and ammonia escape amount can be obtained in a timely and accurate manner. Through automated real-time control, the ammonia injection amount of each ammonia injection pipe can be flexibly adjusted to ensure denitrification efficiency while reducing ammonia escape rate and preventing secondary air pollution.

[0022] Preferably, multiple ammonia injection pipes are arranged to extend into the ammonia injection grid in a crisscross pattern.

[0023] By adopting the above technical solution, it is ensured that ammonia is injected evenly at the cross-section of the flue through multiple ammonia injection pipes, and that the ammonia gas injected during the denitrification process can fully react with nitrogen oxides, thereby improving the reaction efficiency.

[0024] Preferably, the outlet of the ammonia injection pipe is located on the leeward side of the ammonia injection grid.

[0025] By adopting the above technical solution, it is ensured that multiple ammonia injection pipes inject ammonia into the flue gas along the flue gas flow direction, thereby improving the efficiency of full contact reaction.

[0026] Preferably, each of the ammonia injection pipes is equipped with a flow regulating device at its inlet, and the flow regulating device is connected to the central control center via a signal connection.

[0027] By adopting the above technical solution, each ammonia injection pipe can respond to the signal control of the central control center in real time and adjust the ammonia injection volume according to real-time detection data.

[0028] Preferably, the flow regulating device is a flow regulating valve.

[0029] By adopting the above technical solution, the precise adjustment of ammonia injection volume can be achieved in a simple and efficient manner.

[0030] Preferably, the central control center includes a main receiving unit, a sub-receiving unit, and a processing unit, wherein the main receiving unit is used to receive and store the information transmitted by the main monitoring system;

[0031] Multiple sub-receiving units are provided to receive and store information transmitted by multiple sub-monitoring systems respectively;

[0032] The processing unit includes a first processing module, a second processing module, a third processing module, a fourth processing module, a fifth processing module, and a sixth processing module;

[0033] The first processing module is used to obtain the theoretically required ammonia concentration at the outlet of each ammonia injection pipe based on the information transmitted by the main monitoring system;

[0034] The second processing module is used to obtain the average ammonia concentration of the entire ammonia injection grid based on the information transmitted by the multiple sub-monitoring systems;

[0035] The third processing module is used to obtain the theoretical concentration difference of ammonia injection amount for each ammonia injection pipe based on the real-time detection concentration of ammonia gas at the outlet of each ammonia injection pipe and the theoretical required ammonia gas concentration.

[0036] The fourth processing module is used to obtain the actual concentration difference of ammonia injection amount in each ammonia injection pipe based on the real-time detection concentration of ammonia at the outlet of each ammonia injection pipe and the average ammonia concentration at the outlet of multiple ammonia injection pipes.

[0037] The fifth processing module is used to obtain the difference between the actual concentration difference of ammonia injection volume in each ammonia injection pipe and the theoretical concentration difference of ammonia injection volume in each ammonia injection pipe.

[0038] The sixth processing module is used to determine the difference between the output of the fifth processing module and the preset ammonia escape concentration. If the difference is greater than the preset ammonia escape concentration, the sixth processing module activates the corresponding flow regulating device to reduce the ammonia injection volume of the corresponding ammonia injection pipe in real time.

[0039] By adopting the above technical solution, the control precision is high, the uniformity of the ammonia-nitrogen ratio is improved, and the input ammonia injection quantity and hydroxide are fully reacted.

[0040] Preferably, both the main monitoring system and the sub-monitoring system are online flue gas monitoring systems.

[0041] By adopting the above technical solution, the detection accuracy and intelligence are high, and the concentration of hydroxide and ammonia can be obtained in real time with precision, quantified to the real-time control of each ammonia injection pipe.

[0042] In summary, this application includes at least one of the following beneficial technical effects:

[0043] 1. The method disclosed in this application can obtain the real-time flow rate of ammonia at the inlet of each ammonia injection pipe and the real-time value of hydroxide at the flue gas inlet, realize online detection, real-time feedback and real-time adjustment, accurately control the flow rate of injected ammonia, and effectively reduce the amount of ammonia escape.

[0044] 2. The scheme disclosed in this application can characterize the operation of the SCR denitrification device, and can reflect the denitrification efficiency and ammonia slip more timely and accurately, thus preventing secondary air pollution.

[0045] 3. This application has a high degree of automation and accuracy, and is easy to promote. Attached Figure Description

[0046] Figure 1 This is a flowchart illustrating the method for monitoring the ammonia slip rate of the SCR in this application.

[0047] Figure 2 This is a schematic diagram of the central control center in the SCR ammonia slip rate monitoring system of this application. Detailed Implementation

[0048] The following is in conjunction with the appendix Figure 1 To be continued Figure 2 This application will be described in further detail.

[0049] Reference Figure 1 The first aspect of this application discloses a method for monitoring the ammonia slip rate of SCR, specifically including the following steps: S101, obtaining the theoretical concentration difference of ammonia injection amount for each ammonia injection pipe based on the real-time detected ammonia concentration at the outlet of each ammonia injection pipe and the theoretically required ammonia concentration; wherein, the method for obtaining the theoretically required ammonia concentration is as follows: obtaining the theoretical nitrogen oxide concentration at the outlet of each ammonia injection pipe based on the real-time detected nitrogen oxide concentration at the flue gas inlet; the ammonia concentration at the outlet of each ammonia injection pipe obtained according to the denitrification reaction formula is the theoretically required ammonia concentration, which can obtain the real-time nitrogen oxide concentration at the flue gas inlet, unlike the existing method of obtaining the ammonia injection amount based on a fixed ammonia-nitrogen molar ratio, its detection accuracy is higher, making the overall ammonia injection amount control more precise.

[0050] S102, based on the real-time detected ammonia concentration at the outlet of each ammonia injection pipe and the average ammonia concentration at the outlet of multiple ammonia injection pipes, obtain the actual concentration difference of ammonia injection amount in each ammonia injection pipe.

[0051] S103, obtain the difference between the actual concentration difference of ammonia injected into each ammonia injection pipe and the theoretical concentration difference of ammonia injected into each ammonia injection pipe.

[0052] S104. If the difference is greater than the preset ammonia slip concentration, the ammonia injection rate of the corresponding ammonia injection pipe is reduced; if the difference is negative, the ammonia injection rate of the corresponding ammonia injection pipe is increased. The preset ammonia slip concentration is 3 ppm. That is, if the difference is greater than 3 ppm, the flow rate of the corresponding ammonia injection pipe is reduced to prevent excess ammonia from escaping and failing to react. By reducing the flow rate, the amount of input ammonia is matched with the amount of nitrogen oxides, ensuring sufficient reaction of nitrogen oxides and preventing unreacted ammonia. If the difference is negative, it means that the amount of input ammonia cannot react with all nitrogen oxides, resulting in some nitrogen oxides failing to complete denitrification. Therefore, the flow rate of the corresponding ammonia injection pipe is increased in real time to provide more ammonia to react successfully with the input nitrogen oxides and achieve the expected nitrogen oxide denitrification.

[0053] In this embodiment, δ1 = n i -N i δ2=n i -Δn; δ3=δ2-δ1.

[0054] Where, N i n is the theoretically required ammonia concentration. iThe ammonia concentration at the outlet of each ammonia injection pipe is monitored in real time. Δn is the average ammonia concentration at the outlet of each ammonia injection pipe. δ1 is the theoretical concentration difference of ammonia injection amount per ammonia injection pipe, δ2 is the actual concentration difference of ammonia injection amount per ammonia injection pipe, and δ3 is the difference between the actual concentration difference of ammonia injection amount per ammonia injection pipe and the theoretical concentration difference of ammonia injection amount per ammonia injection pipe. This improves the conversion efficiency of the SCR catalyst and reduces air pollution.

[0055] Furthermore, in S101, the NOx concentration at the SCR inlet can be obtained at a certain moment during operation, and the theoretical NOx concentration at the outlet of each ammonia injection pipe can be calculated; the specific reaction formulas are: 4NO+4NH3+O2→4N2+6H2O; 2NO2+4NH3+O2→3N2+6H2O.

[0056] The implementation principle of the SCR ammonia slip rate monitoring method in this application embodiment is as follows: it can timely and accurately feed back the real-time flow rate of ammonia at the inlet of each ammonia injection pipe, timely and accurately feed back the real-time NOx value at the inlet of the SCR denitrification device, and quickly obtain the required amount of ammonia. Then, it can adjust the ammonia flow rate in real time according to the difference, accurately control the injected ammonia flow rate, reduce ammonia slip, and reduce environmental pollution.

[0057] The second aspect of this application provides a monitoring system for SCR ammonia slip rate, including a central control center, a main monitoring system, and multiple sub-monitoring systems. The main monitoring system and multiple monitoring devices are all connected to the central control center via signals. The main monitoring system is used to monitor the nitrogen oxide concentration at the flue gas inlet in real time to obtain accurate NOx concentration information. The solution disclosed in this application has a fast response, high detection accuracy, real-time monitoring and dynamic adjustment of each ammonia injection pipe, matching the NOx distribution in the flue gas, high reaction efficiency, and effectively reduces the maintenance of equipment such as ammonia injection nozzles and ammonia supply regulating valves, thereby improving service life.

[0058] Multiple sub-monitoring systems are set up corresponding to multiple ammonia injection pipes to monitor the ammonia concentration at the outlet of the corresponding ammonia injection pipe in real time, achieving one-to-one monitoring and ensuring monitoring accuracy. The multiple ammonia injection pipes are arranged to extend into the ammonia injection grid in a cross manner to ensure uniform ammonia injection at the cross section of the flue, prevent blockage, and ensure that the ammonia injected during the denitrification process can fully react with nitrogen oxides, thereby improving reaction efficiency.

[0059] The outlet of the ammonia injection pipe is located on the leeward side of the ammonia injection grid to ensure that multiple ammonia injection pipes inject ammonia into the flue gas along the flue gas flow direction, thereby improving the efficiency of full contact reaction. The ammonia injection grid in this application is used to uniformly inject the ammonia provided by multiple ammonia injection pipes into the flue gas to achieve full reaction of the injected ammonia and prevent unreacted ammonia from escaping.

[0060] Each ammonia injection pipe is equipped with a flow regulating device at its inlet. The flow regulating device is connected to the central control center, and each ammonia injection pipe can respond to the signal control of the central control center in real time and adjust the ammonia injection volume according to real-time detection data.

[0061] In operation, the central control center uses the acquired nitrogen oxide concentration at the flue gas inlet and ammonia concentration at the ammonia injection pipe outlet to adjust the flow rate of the corresponding ammonia injection pipe in real time. This solution can obtain the flue gas velocity distribution at the ammonia injection point and the nitrogen oxide concentration distribution in the inlet flue gas in real time, and obtain the denitrification efficiency and ammonia escape in a timely and accurate manner. Through automated real-time control, the ammonia injection volume of each ammonia injection pipe can be flexibly adjusted to ensure denitrification efficiency while reducing ammonia escape rate and preventing secondary air pollution.

[0062] In this embodiment, the flow regulating device is preferably a flow regulating valve, which is simple, efficient, and can achieve precise adjustment of the ammonia injection volume.

[0063] Reference Figure 2 The central control center includes a main receiving unit, sub-receiving units, and a processing unit. The main receiving unit is used to receive and store information transmitted by the main monitoring system. Multiple sub-receiving units are set up to receive and store information transmitted by multiple sub-monitoring systems respectively.

[0064] The processing unit includes a first processing module, a second processing module, a third processing module, a fourth processing module, a fifth processing module, and a sixth processing module. The first processing module is connected to the main monitoring system and is used to obtain the theoretically required ammonia concentration at the outlet of each ammonia injection pipe based on information transmitted from the main monitoring system. The second processing module is used to obtain the average ammonia concentration of the entire ammonia injection grid based on information transmitted from multiple sub-monitoring systems. The third processing module is used to obtain the theoretical concentration difference of ammonia injection volume for each ammonia injection pipe based on the real-time detected ammonia concentration at the outlet of each ammonia injection pipe and the theoretically required ammonia concentration. The fourth processing module is used to obtain the theoretical concentration difference of ammonia injection volume for each ammonia injection pipe based on the real-time detected ammonia concentration at the outlet of each ammonia injection pipe. The ammonia concentration at the outlet is monitored in real time, and the average ammonia concentration at the outlet of multiple ammonia injection pipes is compared with that at the outlet of the ammonia injection pipes to obtain the actual concentration difference of the ammonia injection volume of each ammonia injection pipe. The fifth processing module is used to obtain the difference between the actual concentration difference of the ammonia injection volume of each ammonia injection pipe and the theoretical concentration difference of the ammonia injection volume of each ammonia injection pipe. The sixth processing module is used to judge the difference output by the fifth processing module and the preset ammonia escape concentration. If the difference is greater than the preset ammonia escape concentration, the sixth processing module triggers the corresponding flow regulation device to reduce the ammonia injection volume of the corresponding ammonia injection pipe in real time, so as to achieve high-precision control, improve the uniformity of the ammonia-nitrogen ratio, and achieve the full reaction of the input ammonia injection volume with hydroxide.

[0065] Both the main monitoring system and the sub-monitoring system are online flue gas monitoring systems, namely CEMS, which have high detection accuracy and intelligence. They can obtain accurate concentrations of hydroxide and ammonia in real time and quantify them to the real-time control of each ammonia injection pipe.

[0066] Existing SCR denitrification technology employs uniform ammonia injection and single-point control, determining the ammonia injection amount based on the ammonia-nitrogen molar ratio. This ignores the uneven distribution of flue gas velocity and NOx concentration at the ammonia injection point, leading to reduced denitrification efficiency. To achieve high denitrification efficiency, excessive ammonia needs to be injected, resulting in excessively high ammonia concentration at the flue gas outlet, causing ammonia escape and environmental pollution. The scheme disclosed in this application can characterize the operation of the SCR denitrification device, reflecting denitrification efficiency and ammonia escape more promptly and accurately, preventing secondary air pollution.

[0067] It should be noted that in the description of this invention, terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are based on the direction or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0068] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0069] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to those processes, articles, or apparatus / devices.

[0070] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for monitoring the ammonia slip rate of an SCR system, characterized in that: The method includes the following steps: Based on the real-time detected ammonia concentration at the outlet of each ammonia injection pipe and the theoretically required ammonia concentration, the theoretical concentration difference of the ammonia injection rate for each ammonia injection pipe is obtained. The specific method for obtaining the theoretically required ammonia concentration is as follows: Based on the real-time nitrogen oxide concentration detected at the flue gas inlet, the theoretical nitrogen oxide concentration at the outlet of each ammonia injection pipe is obtained. The ammonia concentration at the outlet of each ammonia injection pipe obtained according to the denitrification reaction formula is the theoretically required ammonia concentration. Based on the real-time ammonia concentration detected at the outlet of each ammonia injection pipe and the average ammonia concentration at the outlets of multiple ammonia injection pipes, the actual concentration difference of ammonia injection amount in each ammonia injection pipe is obtained. Obtain the difference between the actual concentration difference of ammonia injected into each ammonia injection pipe and the theoretical concentration difference of ammonia injected into each ammonia injection pipe; If the difference is greater than the preset ammonia escape concentration, the ammonia injection rate of the corresponding ammonia injection pipe is reduced; if the difference is negative, the ammonia injection rate of the corresponding ammonia injection pipe is increased.

2. The method for monitoring SCR ammonia slip rate according to claim 1, characterized in that: The preset ammonia escape concentration is 3 ppm.

3. A monitoring system for SCR ammonia slip rate, characterized in that: It includes a central control center, a main monitoring system, and multiple sub-monitoring systems, all of which are connected to the central control center via signal transmission. The main monitoring system is used to monitor the concentration of nitrogen oxides at the flue gas inlet in real time. Each of the aforementioned sub-monitoring systems is respectively set up with a corresponding ammonia injection pipe to monitor the ammonia concentration at the outlet of the corresponding ammonia injection pipe in real time; The central control center includes a main receiving unit, a sub-receiving unit, and a processing unit. The main receiving unit is used to receive and store the information transmitted by the main monitoring system. Multiple sub-receiving units are provided to receive and store information transmitted by multiple sub-monitoring systems respectively; The processing unit includes a first processing module, a second processing module, a third processing module, a fourth processing module, a fifth processing module, and a sixth processing module; The first processing module is used to obtain the theoretically required ammonia concentration at the outlet of each ammonia injection pipe based on the information transmitted by the main monitoring system; The second processing module is used to obtain the average ammonia concentration of the entire ammonia injection grid based on the information transmitted by the multiple sub-monitoring systems; The third processing module is used to obtain the theoretical concentration difference of ammonia injection amount for each ammonia injection pipe based on the real-time detection concentration of ammonia gas at the outlet of each ammonia injection pipe and the theoretical required ammonia gas concentration. The fourth processing module is used to obtain the actual concentration difference of ammonia injection amount in each ammonia injection pipe based on the real-time detection concentration of ammonia at the outlet of each ammonia injection pipe and the average ammonia concentration at the outlet of multiple ammonia injection pipes. The fifth processing module is used to obtain the difference between the actual concentration difference of ammonia injection volume in each ammonia injection pipe and the theoretical concentration difference of ammonia injection volume in each ammonia injection pipe. The sixth processing module is used to determine the difference between the output of the fifth processing module and the preset ammonia escape concentration. If the difference is greater than the preset ammonia escape concentration, the sixth processing module triggers the corresponding flow regulating device to reduce the ammonia injection volume of the corresponding ammonia injection pipe in real time. If the difference is negative, the sixth processing module triggers the corresponding flow adjustment device to increase the ammonia injection volume of the corresponding ammonia injection pipe in real time. The central control center uses the aforementioned processing modules to achieve real-time flow control of the corresponding ammonia injection pipes.

4. The SCR ammonia slip monitoring system according to claim 3, characterized in that: Multiple ammonia injection pipes are arranged to cross and extend into the ammonia injection grid.

5. The SCR ammonia slip monitoring system according to claim 4, characterized in that: The outlet of the ammonia injection pipe is located on the leeward side of the ammonia injection grid.

6. The SCR ammonia slip monitoring system according to claim 3, characterized in that: Each of the ammonia injection pipes is equipped with a flow regulating device at its inlet, and the flow regulating device is connected to the central control center via a signal connection.

7. The SCR ammonia slip monitoring system according to claim 6, characterized in that: The flow regulating device is a flow regulating valve.

8. The SCR ammonia slip monitoring system according to claim 3, characterized in that: Both the main monitoring system and the sub-monitoring system are online flue gas monitoring systems.

Images