Denitration ammonia spraying system and method

Abstract

The invention discloses a denitration ammonia spraying system and method, and relates to the field of flue gas treatment. According to the denitration ammonia spraying system, a denitration inlet flue and a denitration outlet flue are internally divided into a plurality of partitions, an ammonia spraying grid and an inlet NOx analyzer are arranged in each inlet partition, partition monitoring and control over the concentration of NOx in flue gas are achieved, and the system can monitor and control the concentration of NOx in the flue gas according to the actual NOx concentration of each partition through partition design. And the valve opening degree of the dilution fan and / or the reducing agent spraying device is dynamically adjusted, so that the spraying amount of the ammonia-air mixture is controlled. The denitration efficiency is improved, ammonia escape is reduced, meanwhile, the adaptability and flexibility of the system are enhanced, the system can better cope with NOx concentration changes under different working conditions, emission of NOx in flue gas can be effectively reduced, the environmental protection requirement is met, and meanwhile the performance and economical efficiency of the whole denitration process are optimized.

Description

Technical Field

[0001] This application relates to the field of flue gas treatment, and more specifically, to a denitration ammonia injection system and method. Background Art

[0002] The flue gas denitration system is currently the most important facility for treating NOx in flue gas of coal-fired power plants. In the existing flue gas denitration system for treating the flue gas of coal-fired power plants, due to different working conditions and combustion conditions, the distribution of NOx in the flat and long flue is extremely uneven, and the distribution law is complex and changeable. In this case, the fixed ammonia injection grid cannot accurately adjust the ammonia injection amount according to the actual distribution of NOx. Since the ammonia injection amount cannot track the change of NOx in real time, it is impossible to accurately match ammonia with NOx. This not only causes a large deviation in the NOx concentration in the flue gas after being treated by the denitration reactor and makes it difficult to achieve a uniform denitration effect, but also may cause the problem of increased local ammonia escape, thereby affecting the denitration efficiency and environmental protection performance. Summary of the Invention

[0003] In view of the above problems, this application proposes a denitration ammonia injection system and method to improve the denitration efficiency. The specific solutions are as follows:

[0004] In a first aspect, a denitration ammonia injection system is provided, including: a dilution fan, a reductant injection device, an ammonia-air mixing device, an ammonia injection grid, an inlet NOx analyzer, a denitration inlet flue, a denitration reactor, and a denitration outlet flue; the same cross-section in the denitration inlet flue is divided into at least one inlet partition, the same cross-section in the denitration outlet flue is divided into at least one outlet partition, and the ammonia injection grid and the inlet NOx analyzer are arranged in each of the inlet partitions; the number of the reductant injection device, the ammonia-air mixing device, the ammonia injection grid, the inlet NOx analyzer, the denitration reactor, the inlet partition, and the outlet partition is the same and they correspond one by one; the outlet of the dilution fan is connected to the air inlet of the ammonia-air mixing device, and the outlet of the reductant injection device is connected to the ammonia inlet of the ammonia-air mixing device; the inlet NOx analyzer is used to detect the first NOx concentration of the corresponding inlet partition and determine the valve opening of the dilution fan and / or the valve opening of the reductant injection device.

[0005] In a possible design, in another implementation manner of the first aspect of the embodiments of the present application, it further includes an outlet NOx analyzer, the outlet NOx analyzer is installed in the outlet partition, the number of the outlet NOx analyzers is the same as and corresponds one-to-one to the number of the outlet partitions, the outlet NOx analyzer is used to detect the second NOx concentration of the target mixture generated by the denitration reactor in the corresponding outlet partition, and is combined with the inlet NOx analyzer to determine the valve opening of the dilution blower and / or the valve opening of the reductant injection device.

[0006] In a possible design, in another implementation manner of the first aspect of the embodiments of the present application, it further includes a controller, the controller is connected to the inlet NOx analyzer, the outlet NOx analyzer, the dilution blower and the reductant injection device;

[0007] The controller is used to determine the valve opening of the dilution blower and / or the valve opening of the reductant injection device according to the first NOx concentration and the second NOx concentration, and control and adjust the valve opening of the dilution blower and / or the valve opening of the reductant injection device.

[0008] In a possible design, in another implementation manner of the first aspect of the embodiments of the present application, the controller is used to determine the valve opening of the dilution blower and / or the valve opening of the reductant injection device according to the first NOx concentration and the second NOx concentration, including:

[0009] The controller is used to determine the valve opening of the dilution blower and / or the valve opening of the reductant injection device according to the first NOx concentration, the second NOx concentration and the configured valve opening determination strategy, the valve opening determination strategy is used to characterize determining the valve opening of the dilution blower and / or the valve opening of the reductant injection device according to the preset weight of the first NOx concentration and the weight of the second NOx concentration, and the weight of the second NOx concentration is greater than the weight of the first NOx concentration.

[0010] In a possible design, in another implementation manner of the first aspect of the embodiments of the present application, the outlet of the dilution blower is connected to the air inlet of the ammonia-air mixing device, including:

[0011] The number of dilution air branches of the dilution blower is the same as and corresponds one-to-one to the number of the ammonia-air mixing devices, the inlet of the dilution air branch is connected to the outlet of the dilution blower, and the outlet of the dilution air branch is connected to the air inlet of the corresponding ammonia-air mixing device.

[0012] In a possible design, in another implementation manner of the first aspect of the embodiments of the present application, the reducing agent used by the reducing agent injection device includes urea solution or ammonia gas.

[0013] In a second aspect, a denitration ammonia injection method is provided, which is applied to a denitration ammonia injection system. The denitration ammonia injection system includes a dilution blower, a reducing agent injection device, an ammonia-air mixing device, an ammonia injection grid, an inlet NOx analyzer, a denitration inlet flue, a denitration reactor, and a denitration outlet flue; the same cross-section in the denitration inlet flue is divided into at least one inlet partition, and the same cross-section in the denitration outlet flue is divided into at least one outlet partition. The ammonia injection grid and the inlet NOx analyzer are arranged in each of the inlet partitions; the number of the reducing agent injection device, the ammonia-air mixing device, the ammonia injection grid, the inlet NOx analyzer, the denitration reactor, the inlet partition, and the outlet partition is the same and they correspond one by one; the outlet of the dilution blower is connected to the air inlet of the ammonia-air mixing device, and the outlet of the reducing agent injection device is connected to the ammonia inlet of the ammonia-air mixing device; the method includes:

[0014] Obtain the first NOx concentration of the corresponding inlet partition through the inlet NOx analyzer, and determine the valve opening of the dilution blower and / or the valve opening of the reducing agent injection device according to the first NOx concentration;

[0015] Output dilution air to the corresponding ammonia-air mixing device through the dilution blower, output a reducing agent to the corresponding ammonia-air mixing device through the reducing agent injection device, and mix the dilution air and the reducing agent through the ammonia-air mixing device to generate an ammonia-air mixture;

[0016] Input the ammonia-air mixture to the corresponding ammonia injection grid through the ammonia-air mixing device, and input the ammonia-air mixture to the corresponding inlet partition through the ammonia injection grid;

[0017] When the ammonia-air mixture and the flue gas in the inlet partition enter the corresponding denitration reactor, use the ammonia-air mixture to perform denitration treatment on the flue gas through the denitration reactor, and input the generated target mixture to the corresponding outlet partition.

[0018] In a possible design, in another implementation manner of the second aspect of the embodiments of the present application, the denitration ammonia injection system further includes an outlet NOx analyzer, the outlet NOx analyzer is installed in the outlet partition, and the number of the outlet NOx analyzer is the same as that of the outlet partition and they correspond one by one;

[0019] Before determining the valve opening of the dilution blower and / or the valve opening of the reducing agent injection device according to the first NOx concentration, it further includes:

[0020] Detect the second NOx concentration of the target mixture in the corresponding outlet partition through the outlet NOx analyzer;

[0021] Determine the valve opening of the dilution fan and / or the valve opening of the reductant injection device according to the first NOx concentration, including:

[0022] Combine the first NOx concentration and the second NOx concentration to determine the valve opening of the dilution fan and / or the valve opening of the reductant injection device.

[0023] In a possible design, in another implementation manner of the second aspect of the embodiments of the present application, the denitration ammonia injection system further includes a controller, the controller is connected to the inlet NOx analyzer, the outlet NOx analyzer, the dilution fan and the reductant injection device, and the controller is configured to determine and adjust the valve opening of the dilution fan and / or the valve opening of the reductant injection device;

[0024] Combine the first NOx concentration and the second NOx concentration to determine the valve opening of the dilution fan and / or the valve opening of the reductant injection device, including:

[0025] Determine the valve opening of the dilution fan and / or the valve opening of the reductant injection device through the controller according to the first NOx concentration and the second NOx concentration.

[0026] In a possible design, in another implementation manner of the second aspect of the embodiments of the present application, determining the valve opening of the dilution fan and / or the valve opening of the reductant injection device through the controller according to the first NOx concentration and the second NOx concentration includes:

[0027] Determine the valve opening of the dilution fan and / or the valve opening of the reductant injection device through the controller according to the first NOx concentration, the second NOx concentration and the configured valve opening determination strategy, the valve opening determination strategy is used to characterize determining the valve opening of the dilution fan and / or the valve opening of the reductant injection device according to the preset weight of the first NOx concentration and the weight of the second NOx concentration, and the weight of the second NOx concentration is greater than the weight of the first NOx concentration.

[0028] With the above technical solution, the denitration ammonia injection system proposed in this application divides multiple zones in the denitration inlet flue and the denitration outlet flue, and arranges ammonia injection grids and inlet NOx analyzers in each inlet zone, realizing the zonal monitoring and control of the NOx concentration in the flue gas. The zonal design enables the system to dynamically adjust the valve openings of the dilution fan and / or the reductant injection device according to the actual NOx concentration in each zone, thereby controlling the injection amount of the ammonia-air mixture. This not only improves the denitration efficiency and reduces ammonia slip, but also enhances the adaptability and flexibility of the system, enabling it to better cope with the NOx concentration changes under different working conditions. Through the zonal control and accurate ammonia injection method of the denitration ammonia injection system proposed in this application, the NOx emissions in the flue gas can be effectively reduced, meeting strict environmental protection requirements, and at the same time optimizing the performance and economy of the entire denitration process. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of this application. And throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0030] Figure 1 is a schematic structural diagram of a denitration ammonia injection system provided by an embodiment of this application;

[0031] Figure 2 is another schematic structural diagram of a denitration ammonia injection system provided by an embodiment of this application;

[0032] Figure 3 is a schematic flow diagram of a denitration ammonia injection method provided by an embodiment of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] Before introducing the solution of this application, some technical terms involved in the embodiments of this application are first explained and described:

[0034] Dilution fan: mainly used to output dilution air to prevent safety problems caused by excessive ammonia concentration. The dilution fan blows in a large amount of air to ensure that the ammonia concentration is within a safe range when ammonia is injected into the reactor. At the same time, the dilution fan can also provide hot air to help maintain the flue gas temperature and avoid affecting the denitration effect due to the temperature reduction of the dilution air.

[0035] Ammonia injection grid: used to evenly inject ammonia or ammonia-containing air into the flue gas. It is usually installed in the flue at the inlet of the reactor and makes the ammonia fully mix with the flue gas through multi-point injection. The design of the ammonia injection grid can include multiple ammonia injection branch pipes and nozzles.

[0036] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0037] Next, refer to Figure 1 , Figure 1 , which is a schematic structural diagram of a denitration ammonia injection system provided by an embodiment of the present application. Next, the denitration ammonia injection system of the embodiment of the present application will be introduced in detail.

[0038] A denitration ammonia injection system may include a dilution fan, a reductant injection device, an ammonia-air mixing device, an ammonia injection grid, an inlet NOx analyzer, as well as a denitration inlet flue, a denitration reactor, and a denitration outlet flue.

[0039] Specifically, in the denitration ammonia injection system, the entire cross-section of the denitration flue can be divided into at least one zone, and the zone design covers all parts of the denitration flue. Specifically, the denitration inlet flue and the denitration outlet flue, as important components of the denitration flue, are also divided into at least one zone respectively. That is, the same cross-section of the denitration inlet flue is divided into at least one inlet zone, and the same cross-section of the denitration outlet flue is divided into at least one outlet zone. An ammonia injection grid and an inlet NOx analyzer are arranged in each inlet zone to monitor the NOx concentration in the inlet zone in real time. At the same time, the number of the reductant injection device, the ammonia-air mixing device, the ammonia injection grid, the inlet NOx analyzer, the denitration reactor, the inlet zone, and the outlet zone in the system is exactly the same and corresponds one by one to ensure that the denitration process of each zone can be carried out independently and accurately.

[0040] The outlet of the dilution fan is connected to the air inlet of the ammonia-air mixing device to provide necessary air for the dilution of ammonia. The outlet of the reductant injection device is connected to the ammonia inlet of the ammonia-air mixing device to transport the reductant into the ammonia-air mixing device. In the ammonia-air mixing device, after the dilution air and the reductant are fully mixed, they are sprayed into the corresponding inlet zone through the ammonia injection grid, mixed with the flue gas, and then enter the denitration reactor for denitration reaction. In an optional manner, the reductant may be a compound containing ammonia component, and the reductants used by the reductant injection device may include two types: urea solution and ammonia, both of which are ammonia-containing compounds.

[0041] The inlet NOx analyzer provides real-time data for the denitration ammonia injection system by detecting the first NOx concentration in the corresponding inlet zone, so as to determine the valve opening of the dilution fan and / or the valve opening of the reductant injection device.

[0042] In the denitration ammonia injection system, the injection amount of ammonia is dynamically adjusted according to the actual concentration of NOx in the inlet flue gas. The adjustment method can be automatic or manual. Whether it is automatic or manual, the purpose is to ensure the denitration efficiency, avoid ammonia escape, and achieve an efficient, energy-saving and environmentally friendly denitration process.

[0043] Furthermore, in some embodiments of the present application, the denitration ammonia injection system may further include an outlet NOx analyzer. Refer to Figure 2 , Figure 2 which is a schematic structural diagram of another denitration ammonia injection system provided by the embodiments of the present application. The following will introduce this part of the content in detail.

[0044] Optionally, in the denitration ammonia injection system, an outlet NOx analyzer can also be equipped. The outlet NOx analyzer can be installed in each outlet partition of the denitration outlet flue, and the number of outlet NOx analyzers is the same as the number of outlet partitions and corresponds one by one. The main function of the outlet NOx analyzer is to detect the second NOx concentration of the target mixture generated after the flue gas is treated by the denitration reactor in the corresponding outlet partition.

[0045] Specifically, the second NOx concentration data detected by the outlet NOx analyzer is combined with the first NOx concentration data detected by the inlet NOx analyzer to obtain the opening degree of the dilution fan valve and / or the opening degree of the reducing agent injection device valve. If the outlet NOx concentration is higher than the set target value, the system can automatically increase the injection amount of the reducing agent or adjust the air volume of the dilution fan to improve the denitration efficiency; conversely, if the outlet NOx concentration is lower than the target value, the system can reduce the injection amount of the reducing agent or adjust the air volume of the dilution fan to avoid ammonia escape and resource waste.

[0046] The adjustment method combining the inlet and outlet NOx concentrations in this embodiment can further realize the control of the denitration ammonia injection process, ensure the denitration efficiency, minimize the ammonia usage amount, reduce the operating cost, and avoid the impact on the environment caused by ammonia escape, thereby achieving an efficient, energy-saving and environmentally friendly denitration ammonia injection process.

[0047] Furthermore, in some embodiments of the present application, the denitration ammonia injection inhalation may further include a controller. The following will introduce this part of the content in detail.

[0048] In the denitration ammonia injection system, a controller may also be included. The controller is connected to the inlet NOx analyzer, the outlet NOx analyzer, the dilution fan, and the reductant injection device. The controller can comprehensively analyze and obtain the valve opening of the dilution fan and / or the valve opening of the reductant injection device based on the first NOx concentration detected by the inlet NOx analyzer and the second NOx concentration detected by the outlet NOx analyzer. Through an intelligent control method, the controller can achieve dynamic adjustment of the denitration ammonia injection system, ensuring the denitration efficiency, minimizing the ammonia usage to the greatest extent, reducing the operation cost, and avoiding the impact on the environment caused by ammonia escape.

[0049] In an alternative manner, the controller can also dynamically adjust the valve opening of the dilution fan and / or the reductant injection device based on the first NOx concentration detected by the inlet NOx analyzer, the second NOx concentration detected by the outlet NOx analyzer, and the valve opening determination strategy configured in the system.

[0050] The valve opening determination strategy can balance the influence of the inlet and outlet NOx concentrations on the valve opening adjustment based on a preset weight. According to this strategy, the weight of the second NOx concentration (i.e., the outlet NOx concentration) is set higher than the weight of the first NOx concentration (i.e., the inlet NOx concentration).

[0051] During actual operation, the controller will calculate the optimal valve opening of the dilution fan and the reductant injection device based on the weight and concentration data. When the outlet NOx concentration is high, due to its larger weight, the controller will give priority to increasing the injection amount of the reductant to ensure that the denitration effect meets the environmental protection requirements. The controller can also adjust the air volume of the dilution fan as needed to ensure an appropriate mixing ratio of ammonia and air and avoid problems such as ammonia escape. On the contrary, if the outlet NOx concentration is lower than the target value, the controller will appropriately reduce the injection amount of the reductant to save resources and reduce the operation cost.

[0052] In this embodiment, through the controller and the valve opening determination strategy based on weight, fine control of the denitration ammonia injection system can be achieved. It not only improves the denitration efficiency, but also minimizes the ammonia usage to the greatest extent, reduces the operation cost, and at the same time avoids the potential impact on the environment caused by ammonia escape, thus realizing an efficient, energy-saving and environmentally friendly denitration ammonia injection process.

[0053] Further, in some embodiments of the present application, the dilution fan can be connected to the ammonia-air mixing device through a dilution air branch pipe. The following will introduce this part in detail.

[0054] Optionally, in the denitration ammonia injection system, the outlet of the dilution fan can be connected to the ammonia-air mixing device through multiple dilution air branch pipes, ensuring that the dilution air can be accurately delivered to each ammonia-air mixing device. The number of dilution air branch pipes of the dilution fan is exactly the same as the number of ammonia-air mixing devices and they are in one-to-one correspondence. Each ammonia-air mixing device has an independent dilution air branch pipe to provide dilution air for it, thus ensuring the uniform distribution and precise control of the dilution air.

[0055] The inlet of each dilution air branch pipe can be connected to the outlet of the dilution fan to ensure that the dilution air can be smoothly drawn out from the fan. The outlet of the dilution air branch pipe can be connected to the air inlet of the corresponding ammonia-air mixing device, enabling the dilution air to accurately enter the ammonia-air mixing device. This not only ensures the stable supply of the dilution air but also, through precise distribution, enables each ammonia-air mixing device to obtain an appropriate amount of dilution air, thereby achieving the optimal mixing ratio of ammonia and air.

[0056] In this embodiment, through the connection of the dilution fan and the dilution air branch pipes, it is ensured that each ammonia-air mixing device can obtain sufficient dilution air, thereby effectively reducing the concentration of ammonia and avoiding the safety risks brought by too high ammonia concentration. At the same time, the dilution air distribution also helps to improve the denitration efficiency, ensuring that ammonia can fully react with NOx in the flue gas, thus realizing an efficient, safe and environmentally friendly denitration process.

[0057] In some embodiments of the present application, it may further include a denitration ammonia injection method applied to the above denitration ammonia injection system. Refer to Figure 3 , Figure 3 which is a schematic flow diagram of a denitration ammonia injection method provided by an embodiment of the present application.

[0058] Specifically, the denitration ammonia injection system may include a dilution fan, a reductant injection device, an ammonia-air mixing device, an ammonia injection grid, an inlet NOx analyzer, as well as a denitration inlet flue, a denitration reactor, and a denitration outlet flue. In the system, the same cross-section of the denitration inlet flue is divided into at least one inlet partition, and the same cross-section of the denitration outlet flue is divided into at least one outlet partition. An ammonia injection grid and an inlet NOx analyzer are arranged in each inlet partition. In addition, the number of the reductant injection device, the ammonia-air mixing device, the ammonia injection grid, the inlet NOx analyzer, the denitration reactor, the inlet partition, and the outlet partition is exactly the same and they are in one-to-one correspondence. The outlet of the dilution fan is communicated with the air inlet of the ammonia-air mixing device, and the outlet of the reductant injection device is communicated with the ammonia inlet of the ammonia-air mixing device.

[0059] Among them, the denitration ammonia injection method is as follows and specifically includes the following steps:

[0060] Step S100: Obtain the first NOx concentration of the corresponding inlet zone through the inlet NOx analyzer, and determine the valve opening of the dilution fan and / or the valve opening of the reductant injection device according to the first NOx concentration.

[0061] Specifically, by installing inlet NOx analyzers in each inlet zone of the denitration inlet flue, the first NOx concentration of the flue gas in each inlet zone is obtained in real time. After obtaining the first NOx concentration data, the system can determine and adjust the valve opening of the dilution fan and / or the valve opening of the reductant injection device manually or automatically. Specifically, if the detected inlet NOx concentration is high, the system can correspondingly increase the valve opening of the reductant injection device to increase the injection amount of the reductant (such as ammonia or urea solution), so as to enhance the denitration effect, enabling the denitration ammonia injection system to adjust the ammonia injection amount and dilution air volume in real time according to the change of flue gas composition under different working conditions, thereby achieving efficient denitration control.

[0062] Step S110: Output dilution air to the corresponding ammonia-air mixing device through the dilution fan, output the reductant to the corresponding ammonia-air mixing device through the reductant injection device, and mix the dilution air and the reductant through the ammonia-air mixing device to generate an ammonia-air mixture.

[0063] Specifically, the dilution fan can provide a certain amount of air to dilute the reductant (such as ammonia or urea solution) to ensure that its concentration is appropriate when sprayed into the flue, so that it can effectively participate in the denitration reaction without causing safety problems or wasting resources due to excessive concentration. The reductant injection device is responsible for precisely delivering the reductant into the system. The dilution air is delivered to each corresponding ammonia-air mixing device through the dilution fan. At the same time, the reductant (such as ammonia or urea solution) is delivered to the corresponding ammonia-air mixing device through the reductant injection device. In the ammonia-air mixing device of the system, the dilution air and the reductant are fully mixed. Only when the dilution air and the reductant are mixed in a suitable ratio can a uniform ammonia-air mixture be generated. The ammonia-air mixture will then be delivered to the ammonia injection grid and evenly sprayed into each inlet zone of the denitration inlet flue through the ammonia injection grid, and enter the denitration reactor for denitration reaction after being fully mixed with the flue gas.

[0064] Step S120: Input the ammonia-air mixture into the corresponding ammonia injection grid through the ammonia-air mixing device, and input the ammonia-air mixture into the corresponding inlet zone through the ammonia injection grid.

[0065] Specifically, after the ammonia-air mixing device completes the mixing of the dilution air and the reducing agent (such as ammonia or urea solution), the generated ammonia-air mixture can be transported to the corresponding ammonia injection grid through a pipeline between the outlet of the ammonia-air mixing device and the inlet of the ammonia injection grid, ensuring that the ammonia-air mixture can be transmitted smoothly and without leakage.

[0066] The ammonia-air mixture is evenly sprayed into the corresponding inlet partition of the denitrification inlet flue through the ammonia spray grid. The ammonia spray grid can be composed of multiple nozzles, which can evenly spray the ammonia-air mixture into the flue gas in the form of fine droplets or airflow, thereby improving the efficiency of the denitrification reaction. Through the coordinated work of the ammonia-air mixing device and the ammonia spray grid, the denitrification ammonia spray system can ensure the full mixing of ammonia and flue gas, thereby achieving an efficient denitrification effect. Not only does it improve the denitrification efficiency, it also minimizes the use of ammonia and the risk of ammonia escape, meeting strict environmental emission requirements.

[0067] Step S130: When the ammonia-air mixture and the flue gas of the inlet partition enter the corresponding denitration reactor, the flue gas is denitrated by the ammonia-air mixture through the denitration reactor, and the generated target mixture is input into the corresponding outlet partition.

[0068] Specifically, when the ammonia-air mixture in the inlet partition is mixed with the flue gas and enters the corresponding denitration reactor, the denitration reactor will function. The denitration reactor is equipped with a catalyst that can significantly reduce the temperature and time required for the chemical reaction between ammonia and nitrogen oxides (NOx) in the flue gas. In the reactor, the ammonia (NH3) in the ammonia-air mixture undergoes an oxidation-reduction reaction with the NOx in the flue gas to generate harmless nitrogen (N2) and water vapor (H2O), thereby achieving denitration of the flue gas. The flue gas treated by the denitration reactor, that is, the generated target mixture, is then input into the corresponding outlet partition.

[0069] Furthermore, in some embodiments of the present application, the denitrification ammonia injection method can also utilize an outlet NOx analyzer to further determine the valve opening of the dilution fan and / or the valve opening of the reductant injection device, which is described in detail below.

[0070] Specifically, the denitrification ammonia injection system may include not only an inlet NOx analyzer for monitoring the NOx concentration in the inlet flue gas, but also an outlet NOx analyzer. The outlet NOx analyzer may be installed in each outlet partition of the denitrification outlet flue, and the number of the outlet NOx analyzers may be consistent with the number of outlet partitions, and correspond one to one.

[0071] Before determining the valve opening of the dilution fan and / or the valve opening of the reductant injection device according to the first NOx concentration in the inlet partition, the system can first detect the second NOx concentration of the target mixture in the corresponding outlet partition through an outlet NOx analyzer to determine the actual effect data after the denitration reaction. The second NOx concentration reflects the remaining concentration of NOx in the flue gas after being treated by the denitration reactor.

[0072] When determining the valve opening of the dilution fan and / or the reductant injection device, the system comprehensively considers the first NOx concentration and the second NOx concentration. Specifically, the first NOx concentration in the inlet partition can be combined with the second NOx concentration in the outlet partition, and through a preset control logic, the valve opening of the dilution fan and / or the valve opening of the reductant injection device can be obtained. Adjust the valve opening of the dilution fan and the valve opening of the reductant injection device through manual or automated adjustment methods.

[0073] For example, if the outlet NOx concentration (the second NOx concentration) is higher than the set target value, it indicates that the denitration effect does not meet the expectation. The system can appropriately increase the injection amount of the reductant or adjust the dilution air volume according to this data to improve the denitration efficiency. On the contrary, if the outlet NOx concentration is lower than the target value, the system will reduce the injection amount of the reductant to save resources and reduce the operating cost.

[0074] Furthermore, in some embodiments of the present application, the valve opening of the dilution fan and / or the valve opening of the reductant injection device can be determined and adjusted by a controller. The following is a detailed introduction to this part of the content.

[0075] Optionally, the denitration ammonia injection system can further include a controller, which is connected to the inlet NOx analyzer, the outlet NOx analyzer, the dilution fan, and the reductant injection device. The controller can be responsible for receiving data from the analyzer and determining and adjusting the valve opening of the dilution fan and / or the valve opening of the reductant injection device according to these data to ensure the high efficiency and accuracy of the denitration process.

[0076] The controller can calculate the appropriate valve opening according to the received first NOx concentration (i.e., the NOx concentration in the inlet flue gas) and the second NOx concentration (i.e., the NOx concentration in the outlet flue gas after being treated by the denitration reactor).

[0077] An optional method is that the controller can determine the valve opening of the dilution fan and / or the reductant injection device according to the first NOx concentration and the second NOx concentration, in combination with the valve opening determination strategy configured in the system. The valve opening determination strategy is a preset control rule that determines the valve opening according to the weights of the first NOx concentration and the second NOx concentration, and the weight of the second NOx concentration is set to be greater than the weight of the first NOx concentration. Through the valve opening determination strategy based on weights, the controller can more accurately adjust the valve opening of the dilution fan and / or the reductant injection device. For example, if the outlet NOx concentration (the second NOx concentration) is higher than the set target value, the controller will, based on this higher weight, give priority to increasing the injection amount of the reductant to improve the denitration efficiency. At the same time, the controller can also adjust the air volume of the dilution fan as needed to ensure an appropriate mixing ratio of ammonia and air and avoid problems such as ammonia slip.

[0078] In this embodiment, the controller comprehensively considers the inlet and outlet NOx concentrations and can also be adjusted according to the preset weights, enabling the denitration ammonia injection system to achieve an efficient, energy-saving and environmentally friendly denitration process. By precisely controlling the injection amount of ammonia and the dilution air volume, the system can not only ensure the denitration efficiency, but also minimize the ammonia usage and the risk of ammonia slip, meeting the strict environmental emission requirements.

[0079] In the description of the embodiments of the present application, it should be understood that if terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0080] In addition, if terms such as "first" and "second" are only used for descriptive purposes, they cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the embodiments of the present application, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0081] In the embodiments of the present application, unless otherwise clearly specified or limited, terms such as "installed", "connected", "coupled", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or communicable with each other; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application may be understood according to specific circumstances.

[0082] In the embodiments of the present application, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0083] In the embodiments of the present application, terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0084] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

[0085] The various embodiments in this specification are described in a progressive manner, with each embodiment highlighting the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referred to each other.

Claims

1. A denitration ammonia injection system, characterized in that, Including: A dilution blower, a reducing agent injection device, an ammonia-air mixing device, an ammonia injection grid, an inlet NOx analyzer, a denitration inlet flue, a denitration reactor, and a denitration outlet flue; The same cross-section in the denitration inlet flue is divided into at least one inlet partition, and the same cross-section in the denitration outlet flue is divided into at least one outlet partition. The ammonia injection grid and the inlet NOx analyzer are arranged in each of the inlet partitions; the numbers of the reducing agent injection device, the ammonia-air mixing device, the ammonia injection grid, the inlet NOx analyzer, the denitration reactor, the inlet partition, and the outlet partition are the same and in one-to-one correspondence; the outlet of the dilution blower is connected to the air inlet of the ammonia-air mixing device, and the outlet of the reducing agent injection device is connected to the ammonia inlet of the ammonia-air mixing device; the inlet NOx analyzer is used to detect the first NOx concentration of the corresponding inlet partition and determine the valve opening of the dilution blower and / or the valve opening of the reducing agent injection device.

2. The system according to claim 1, wherein It further includes an outlet NOx analyzer. The outlet NOx analyzer is installed in the outlet partition. The numbers of the outlet NOx analyzer and the outlet partition are the same and in one-to-one correspondence. The outlet NOx analyzer is used to detect the second NOx concentration of the target mixture generated by the denitration reactor in the corresponding outlet partition and combine with the inlet NOx analyzer to determine the valve opening of the dilution blower and / or the valve opening of the reducing agent injection device.

3. The system according to claim 2, wherein It further includes a controller. The controller is connected to the inlet NOx analyzer, the outlet NOx analyzer, the dilution blower, and the reducing agent injection device; The controller is used to determine the valve opening of the dilution blower and / or the valve opening of the reducing agent injection device according to the first NOx concentration and the second NOx concentration, and control and adjust the valve opening of the dilution blower and / or the valve opening of the reducing agent injection device.

4. The system according to claim 3, wherein The controller is used to determine the valve opening of the dilution blower and / or the valve opening of the reducing agent injection device according to the first NOx concentration and the second NOx concentration, including: The controller is used to determine the valve opening of the dilution blower and / or the valve opening of the reducing agent injection device according to the first NOx concentration, the second NOx concentration, and the configured valve opening determination strategy. The valve opening determination strategy is used to characterize determining the valve opening of the dilution blower and / or the valve opening of the reducing agent injection device according to the preset weight of the first NOx concentration and the weight of the second NOx concentration, and the weight of the second NOx concentration is greater than the weight of the first NOx concentration.

5. The system according to claim 1, wherein The outlet of the dilution blower is connected to the air inlet of the ammonia-air mixing device, including: The dilution air branches of the dilution blower are the same in number as and in one-to-one correspondence with the ammonia-air mixing device. The inlet of the dilution air branch is connected to the outlet of the dilution blower, and the outlet of the dilution air branch is connected to the air inlet of the corresponding ammonia-air mixing device.

6. The system according to any one of claims 1-5, characterized in that The reducing agent used by the reducing agent injection device includes urea solution or ammonia gas.

7. A denitrification ammonia injection method, characterized in that, Applied to the denitration ammonia injection system, the denitration ammonia injection system includes a dilution fan, a reducing agent injection device, an ammonia-air mixing device, an ammonia injection grid, an inlet NOx analyzer, a denitration inlet flue, a denitration reactor, and a denitration outlet flue; the same cross-section in the denitration inlet flue is divided into at least one inlet partition, and the same cross-section in the denitration outlet flue is divided into at least one outlet partition. The ammonia injection grid and the inlet NOx analyzer are arranged in each of the inlet partitions; the number of the reducing agent injection device, the ammonia-air mixing device, the ammonia injection grid, the inlet NOx analyzer, the denitration reactor, the inlet partition, and the outlet partition is the same and they correspond one by one; the outlet of the dilution fan is connected to the air inlet of the ammonia-air mixing device, and the outlet of the reducing agent injection device is connected to the ammonia inlet of the ammonia-air mixing device; the method includes: Obtaining the first NOx concentration of the corresponding inlet partition through the inlet NOx analyzer, and determining the valve opening of the dilution fan and / or the valve opening of the reducing agent injection device according to the first NOx concentration; Outputting dilution air to the corresponding ammonia-air mixing device through the dilution fan, outputting a reducing agent to the corresponding ammonia-air mixing device through the reducing agent injection device, and mixing the dilution air and the reducing agent through the ammonia-air mixing device to generate an ammonia-air mixture; Inputting the ammonia-air mixture into the corresponding ammonia injection grid through the ammonia-air mixing device, and inputting the ammonia-air mixture into the corresponding inlet partition through the ammonia injection grid; When the ammonia-air mixture and the flue gas in the inlet partition enter the corresponding denitration reactor, using the ammonia-air mixture to perform denitration treatment on the flue gas through the denitration reactor, and inputting the generated target mixture into the corresponding outlet partition.

8. The method according to claim 7, wherein The denitration ammonia injection system further includes an outlet NOx analyzer, the outlet NOx analyzer is installed in the outlet partition, and the number of the outlet NOx analyzers is the same as that of the outlet partitions and they correspond one by one; Before determining the valve opening of the dilution fan and / or the valve opening of the reducing agent injection device according to the first NOx concentration, it further includes: Detecting the second NOx concentration of the target mixture in the corresponding outlet partition through the outlet NOx analyzer; Determining the valve opening of the dilution fan and / or the valve opening of the reducing agent injection device according to the first NOx concentration includes: Combining the first NOx concentration and the second NOx concentration to determine the valve opening of the dilution fan and / or the valve opening of the reducing agent injection device.

9. The method according to claim 8, characterized in that The denitration ammonia injection system further includes a controller, the controller is connected to the inlet NOx analyzer, the outlet NOx analyzer, the dilution fan, and the reducing agent injection device, and the controller is used to determine and adjust the valve opening of the dilution fan and / or the valve opening of the reducing agent injection device; Combining the first NOx concentration and the second NOx concentration to determine the valve opening of the dilution blower and / or the valve opening of the reductant injection device, including: Determining the valve opening of the dilution blower and / or the valve opening of the reductant injection device by the controller according to the first NOx concentration and the second NOx concentration.

10. The method according to claim 9, wherein Determining the valve opening of the dilution blower and / or the valve opening of the reductant injection device by the controller according to the first NOx concentration and the second NOx concentration, including: Determining the valve opening of the dilution blower and / or the valve opening of the reductant injection device by the controller according to the first NOx concentration, the second NOx concentration and the configured valve opening determination strategy, where the valve opening determination strategy is used to characterize determining the valve opening of the dilution blower and / or the valve opening of the reductant injection device according to the preset weight of the first NOx concentration and the weight of the second NOx concentration, and the weight of the second NOx concentration is greater than the weight of the first NOx concentration.

Images