An Automatic Adjustment Method for Ammonia Injection in Denitrification Based on Two-Dimensional Sampling Grid

Abstract

This invention relates to an automatic adjustment method for ammonia injection in denitrification systems based on a two-dimensional sampling grid. The method includes: dividing the sampling area into multiple partitions; checking the concentration field of each partition to identify all partitions requiring adjustment; determining whether the adjustment target is a high-concentration or low-concentration area within the partitions requiring adjustment; and determining the corresponding sampling port and adjusting the ammonia injection rate of the corresponding ammonia injection branch pipe according to the adjustment target. The beneficial effects of this invention are: it accurately determines the impact of changes in the ammonia injection flow rate of a specific ammonia injection branch pipe on the NOx concentration in a specific area at the denitrification outlet using a two-dimensional sampling grid, providing a quantitative reference for the automatic and precise adjustment of the ammonia injection grid.

Description

Technical Field

[0001] This invention relates to the field of NOx selectivity, and more specifically, to an automatic adjustment method for ammonia injection in denitrification based on a two-dimensional sampling grid. Background Technology

[0002] Nitrogen oxides (NOx) are one of the main indicators for assessing total air pollutant emissions. With the increasing national efforts to control air pollutants, coal-fired power plants primarily employ SCR (Selective Catalytic Reduction) denitrification technology to treat NOx in flue gas. The core equipment of SCR denitrification technology is the SCR reactor. The process flow of the SCR denitrification reaction is as follows: The raw flue gas from the economizer is first mixed with diluted ammonia at the ammonia injection grid. After uniform mixing, the flue gas (NH3 and NO) is then... x The gas then passes vertically through an SCR reactor equipped with a denitrification catalyst, where a selective catalytic reduction reaction occurs, generating environmentally friendly N2 and H2O, thereby removing NO from the flue gas. x .

[0003] To check the efficiency of the denitrification reaction and control the supply of the denitrification reducing agent NH3 in a closed-loop manner, uniformly distributed flue gas sampling grids were arranged at the outlet of the denitrification reactor. The flue gas sampled from the SCR reactor outlet was introduced into an online flue gas analyzer to monitor the denitrification reaction in real time. The traditional denitrification outlet flue gas sampling grid arrangement is as follows: Figure 1 The sampling ports are evenly distributed on several sampling branches arranged horizontally or vertically. The collected flue gas is collected through each branch and then introduced into the online flue gas analyzer to obtain the average NOx concentration of the overall flue gas.

[0004] Traditional denitrification flue gas sampling grids have obvious drawbacks: 1. They only provide the average value of NOx in the flue gas and cannot reflect the uneven distribution of NOx in the outlet flue gas. They cannot adjust the opening of the ammonia injection grid in a timely manner when the load and combustion conditions change; 2. They cannot automatically control the amount of ammonia injected into each branch pipe to ensure the uniformity of the denitrification reaction. They must be checked and adjusted by professional technicians, which is time-consuming and labor-intensive. Therefore, they have a significant impact on the safety and economic operation of the unit equipment.

[0005] Given the numerous inconveniences of traditional ammonia injection grids, some professionals have attempted optimization measures such as zoning improvements. For example, electric valves are installed on each branch of the sampling grid to test the NOx distribution in each branch area in turn, guiding upstream zoning ammonia injection. Other methods involve directly arranging multiple flue gas analyzers at the denitrification outlet flue section to test the NOx concentration distribution. While these optimizations have achieved some success, they still have significant limitations: 1. While multi-point cyclic sampling establishes zoning control based on sampling branch units, it remains a one-dimensional zoning system (horizontal or vertical) and cannot automatically adjust the ammonia injection distribution online; 2. Directly installing multiple flue gas analyzers incurs substantial equipment and maintenance costs. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide an automatic adjustment method for denitrification ammonia injection based on a two-dimensional sampling grid.

[0007] Firstly, a method for automatically adjusting ammonia injection for denitrification based on a two-dimensional sampling grid is provided, including:

[0008] S1. Divide the sampling area into multiple partition blocks, each partition block including multiple horizontal sampling branches and multiple vertical sampling branches with sampling ports;

[0009] S2. Check the concentration field of the partition blocks to identify all partition blocks that need adjustment;

[0010] S3. In the partition blocks that need to be adjusted, determine whether the adjustment target is a high-concentration area or a low-concentration area;

[0011] S4. Determine the corresponding sampling port based on the adjustment target;

[0012] S5. Based on the sampling port determined in S4, adjust the ammonia injection rate of the corresponding ammonia injection branch pipe.

[0013] Preferably, in S2, the NOx concentration in the sample gas from the transverse and longitudinal sampling branches is extracted and recorded sequentially. The coefficient of variation (Cv) reflecting the uniformity of the NOx concentration field at the outlet is calculated. When the Cv value is greater than a set threshold, the affected area is determined to be the area requiring adjustment. The formula for calculating the Cv value is:

[0014]

[0015]

[0016] Where n is the number of measurement points, x i These are the measured values ​​at each measuring point. This is the average value of all measurement points.

[0017] As a preferred option, in S3, the average NOx concentration A of all sample gases is recorded; the highest NOx concentration Amax and the lowest NOx concentration Amin are recorded, and the absolute values ​​of their deviations from the average value, |A-Amax| and |A-Amin|, are compared, with the larger one being the adjustment target.

[0018] Preferably, in S4, when the target is a high-concentration area, the branch pipe with the highest horizontal NOx concentration and the branch pipe with the highest vertical NOx concentration are found, and the sampling port at the intersection of the two branches is determined as the sampling area with the highest concentration in the partition block; when the target is a low-concentration area, the branch pipe with the lowest horizontal NOx concentration and the branch pipe with the lowest vertical NOx concentration are found, and the sampling port at the intersection of the two branches is determined as the sampling area with the lowest concentration in the partition block.

[0019] As a preferred option, it also includes:

[0020] S6. After adjustment, purge each sampling branch tube.

[0021] In a second aspect, an automatic ammonia injection adjustment device for denitrification based on a two-dimensional sampling grid is provided, for executing the automatic ammonia injection adjustment method for denitrification based on a two-dimensional sampling grid as described in any of the first aspects, comprising: a two-dimensional sampling grid, a denitrification purging instrument, a denitrification flue gas analyzer, a main pipe and an electric valve, wherein the two-dimensional sampling grid includes a transverse sampling grid and a longitudinal sampling grid; the transverse sampling grid includes multiple transverse sampling branches, and the longitudinal sampling grid includes multiple longitudinal sampling branches, wherein both the transverse and longitudinal sampling branches have multiple sampling ports, and there is a corresponding relationship between the sampling ports on the transverse and longitudinal sampling branches.

[0022] Preferably, the transverse sampling branch pipe and the longitudinal sampling branch pipe are connected to the main pipe through corresponding electric valves, and the main pipe is connected to the denitrification flue gas analyzer.

[0023] Preferably, the main pipe is also connected to a denitrification purging device.

[0024] The beneficial effects of this invention are:

[0025] (1) This invention utilizes transverse and longitudinal sampling grids to quickly locate areas with uneven NOx concentration at the outlet by batch gas sampling. Compared with fixed multi-point analyzer layout, it significantly reduces the number of analyzers and investment costs.

[0026] (2) The present invention uses a two-dimensional sampling grid to accurately determine the influence of the change in the ammonia flow rate of a certain ammonia injection branch on the NOx concentration in a specific area of ​​the denitrification outlet, which can provide a quantitative reference for the automatic and precise adjustment of the ammonia injection grid. Attached Figure Description

[0027] Figure 1 A schematic diagram of the structure of a traditional denitrification flue gas sampling grid;

[0028] Figure 2 for Figure 1 A magnified view of a portion of the image;

[0029] Figure 3 This is a schematic diagram of the structure of the transverse sampling grid for denitrification flue gas;

[0030] Figure 4 for Figure 3 A magnified view of a portion of the image;

[0031] Figure 5 This is a schematic diagram of the structure of the longitudinal sampling grid for denitrification flue gas;

[0032] Figure 6 for Figure 5 A magnified view of a portion of the image;

[0033] Figure 7 This is a schematic diagram of the sampling numbering of a two-dimensional sampling grid;

[0034] Figure 8 This is a flowchart of an automatic adjustment method for denitrification ammonia injection based on a two-dimensional sampling grid. Detailed Implementation

[0035] The present invention will be further described below with reference to embodiments. The description of the embodiments below is only for the purpose of helping to understand the present invention. It should be noted that those skilled in the art can make several modifications to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0036] Example 1:

[0037] To eliminate the drawbacks of traditional zoning methods in denitrification ammonia injection systems, this application provides an automatic adjustment method for denitrification ammonia injection based on a two-dimensional sampling grid. This method can achieve zoning sampling and precise automatic control of ammonia injection while saving costs, including:

[0038] S1. Divide the sampling area into multiple partition blocks, each partition block including multiple horizontal sampling branches and multiple vertical sampling branches with sampling ports;

[0039] S2. Check the concentration field of the partition blocks to identify all partition blocks that need adjustment;

[0040] S3. In the partition blocks that need to be adjusted, determine whether the adjustment target is a high-concentration area or a low-concentration area;

[0041] S4. Determine the corresponding sampling port based on the adjustment target;

[0042] S5. Based on the sampling port determined in S4, adjust the ammonia injection rate of the corresponding ammonia injection branch pipe.

[0043] In S2, the NOx concentration in the sample gas from the transverse and longitudinal sampling branches is extracted and recorded sequentially. The coefficient of variation (Cv) reflecting the uniformity of the NOx concentration field at the outlet is calculated. When the Cv value is greater than a set threshold, the block is determined to be the block that needs adjustment. The formula for calculating the Cv value is:

[0044]

[0045]

[0046] Where n is the number of measurement points, x i These are the measured values ​​at each measuring point. This is the average value of all measurement points.

[0047] In S3, record the average NOx concentration A of all sample gases; record the highest NOx concentration Amax and the lowest NOx concentration Amin, and compare the absolute values ​​of their deviations from the average value, |A-Amax| and |A-Amin|, and use the larger one as the adjustment target.

[0048] In S4, when the target is a high-concentration area, the branch pipe with the highest NOx concentration in the horizontal sample gas and the branch pipe with the highest NOx concentration in the vertical sample gas are identified, and the sampling port at the intersection of the two branches is determined as the sampling area with the highest concentration in the partition block. When the target is a low-concentration area, the branch pipe with the lowest NOx concentration in the horizontal sample gas and the branch pipe with the lowest NOx concentration in the vertical sample gas are identified, and the sampling port at the intersection of the two branches is determined as the sampling area with the lowest concentration in the partition block.

[0049] Also includes:

[0050] S6. After adjustment, purge each sampling branch tube.

[0051] An automatic ammonia injection adjustment device for denitrification based on a two-dimensional sampling grid includes: a two-dimensional sampling grid, a denitrification purging device, a denitrification flue gas analyzer, a main pipe, and an electric valve. The two-dimensional sampling grid includes a transverse sampling grid and a longitudinal sampling grid. The transverse sampling grid includes multiple transverse sampling branches, and the longitudinal sampling grid includes multiple longitudinal sampling branches. Both the transverse and longitudinal sampling branches have multiple sampling ports, and there is a corresponding relationship between the sampling ports on the transverse and longitudinal sampling branches. For example, please refer to... Figure 7The transverse sampling branch pipe A1j has three sampling ports (sampling ports #1, #2, and #3), which correspond to the sampling ports #1 of the longitudinal sampling branch pipes Ai1, Ai2, and Ai3, respectively.

[0052] The horizontal and vertical sampling branches are connected to the main pipe via corresponding electric valves, and the main pipe is connected to the denitrification flue gas analyzer.

[0053] The main pipe is also connected to the denitrification purging device.

[0054] Example 2:

[0055] Normal flue gas sampling follows the traditional sampling mode (all horizontal or vertical sampling grid branches are fully open for sampling). The automatic rapid adjustment program for the two-dimensional sampling grid is only activated when severe ammonia injection unevenness occurs. The two-dimensional sampling grid can quickly locate localized areas of excessive ammonia injection at the denitrification outlet section, allowing for targeted adjustments to the ammonia injection grid. The two-dimensional sampling grid mainly consists of: 1. Optimized traditional horizontal sampling grids; 2. Newly added vertical sampling grids. The sampling ports of these two rows of grids are very close together, thus allowing for accurate location of uneven NOx distribution areas at the section through the horizontal and vertical sampling branches. Its main structure is shown in [details omitted]. Figures 3-6 Each sampling branch pipe in the two rows of sampling grids is automatically controlled by an electric valve to sample in turn. The sample gas from each branch pipe is collected and enters the main pipe, and then introduced into an online monitoring instrument (such as a denitrification flue gas analyzer) to obtain the corresponding data. To prevent the sampling gas pipeline from being blocked, the denitrification purging gas is introduced into the sampling main pipe for periodic purging.

[0056] The denitrification reactor is actually divided into multiple groups of two-dimensional sampling modules. The following explanation uses the example of the denitrification reactor being divided into two groups of 3x3 two-dimensional sampling modules. For example... Figure 7 As shown, taking the 3*3 two-dimensional sampling block A on the left as an example, the sampling port is numbered Aij, where i indicates that the sampling port is located in the i-th row of the horizontal grid, and j indicates that the sampling port is located in the j-th column of the vertical grid. All sampling ports in the two-dimensional sampling block A can be represented by numbers A11-A33, the corresponding horizontal branches are represented by A1j, A2j, and A3j, and the corresponding vertical branches are represented by Ai1, Ai2, and Ai3.

[0057] Check and adjust the NOx concentration at the denitrification outlet, taking a typical two-dimensional block A as an example. Figure 8 As shown, the specific steps for initiating the NOx concentration field inspection procedure at the denitrification outlet of Block A are as follows:

[0058] 1. Inspect the concentration field of the zonal blocks. Sequentially sample and record the NOx concentration in the transverse branch pipe and the longitudinal sample gas, and calculate the coefficient of variation (Cv) value, which reflects the uniformity of the outlet NOx concentration field. Where n is the number of measurement points, x i—Measured values ​​at each measuring point —The average value of all measuring points. When the Cv value is too high (e.g., the upper limit can be set to 30%), the subsequent adjustment steps will be initiated; if the Cv value is within the limit range, the output "NOx concentration field at the denitrification outlet meets the requirements" will be displayed.

[0059] 2. Determine the adjustment target. Record the average NOx concentration A of all sample gases; record the highest NOx concentration Amax and the lowest NOx concentration Amin, and compare the absolute values ​​of their deviations from the average value, |A-Amax| and |A-Amin|, and take the larger one as the adjustment target.

[0060] 3. Determine the adjustment area. When the adjustment target is a high-concentration area, locate the branch with the highest NOx concentration in the transverse sample gas, such as A2j; locate the branch with the highest NOx concentration in the longitudinal sample gas, such as Ai3. In this case, the sampling port A23 is confirmed as the sampling area with the highest NOx concentration in block A. When the adjustment target is a low-concentration area, locate the branch with the lowest NOx concentration in the transverse sample gas, such as A2j; locate the branch with the lowest NOx concentration in the longitudinal sample gas, such as Ai3. In this case, the sampling port A23 is confirmed as the sampling area with the lowest NOx concentration in block A.

[0061] Through the above steps, the NOx concentration field at the denitrification outlet was effectively gridded and sampled. The horizontal sampling branch pipes were used to determine the abscissa of the uneven concentration areas, and the vertical sampling branch pipes were used to determine the ordinate of the uneven areas, thus quickly locating these uneven regions. By connecting multi-point sampling analyzers into a series of sampling branch pipes and setting alternating sampling cycles, the entire ammonia injection grid adjustment can be completed using only one flue gas sampling analyzer. Compared to the existing technology that uses a fixed multi-point analyzer arrangement, this significantly reduces the number of analyzers and investment costs.

[0062] 4. Adjusting the ammonia injection rate of the corresponding ammonia injection branch pipe can control the NOx concentration in area A23 to the average range, thereby reducing the unevenness of the denitrification reaction.

[0063] With the ammonia injection flow rate of each ammonia injection branch at the denitrification inlet remaining constant, adjusting the ammonia injection flow rate of a particular branch will change the corresponding NOx concentration field at the denitrification outlet. By using a two-dimensional sampling grid of the corresponding zone, the influence area and degree of this adjustment on the NOx concentration field at the outlet can be accurately located, establishing the correspondence between the ammonia injection branch at the denitrification inlet and the sampling area at the denitrification outlet. Based on this, during automatic adjustment, the corresponding ammonia injection grid branch requiring adjustment can be deduced from the uneven areas at the denitrification outlet, thus automatically adjusting the NOx concentration field at the denitrification outlet.

[0064] In addition, after adjustments are completed, purge all sampling branch pipes. Shut off the sample gas supply to the analyzer gas line, fully close all branch pipe sampling electric valves, open the instrument gas purging main valve, open each branch pipe sampling electric valve one by one, thoroughly clean the accumulated dust in the branch pipes, and then close them. After purging is complete, restore normal flue gas sampling mode.

[0065] It should be noted that the number of two-dimensional sampling grid blocks in this application is not limited to two; multiple blocks can be selected and adjusted for analysis as needed. Furthermore, the number of transverse and longitudinal sampling branches is not limited to three. The number of branches can be appropriately increased to meet the requirement of sampling and analyzing all branch sample gas within the adjustment cycle, based on the instrument analyzer's response time. Moreover, the number of sampling ports on each branch is not limited to three and can be appropriately adjusted according to factors such as the size of the sampling grid blocks, the required level of precision control, the branch pipe diameter, and the instrument sampling flow rate.

[0066] Example 3:

[0067] A 660MW unit at a power plant underwent a two-dimensional sampling grid retrofit of its denitrification ammonia injection system, enabling online automatic and rapid adjustment of the system's ammonia injection. The two-dimensional sampling grid is shown below. Figures 3-6 As shown. The modification involved dividing the denitrification reactor cross-section into two sections, A and B, based on the existing traditional sampling grid and using 3×3 sampling ports. Each section has three transverse and longitudinal sampling branches, and each branch has three sampling points, numbered as shown below. Figure 7 .

[0068] The online automatic rapid adjustment system for ammonia injection mainly consists of three steps: 1. Establishing a preliminary understanding of the relationship between the opening degree of the ammonia injection branch pipe and the change in the NOx concentration field at the outlet, in preparation for fine-tuning; 2. Adjusting between different zones; 3. Adjusting within different zones.

[0069] I. Correspondence between the opening degree of the ammonia injection branch pipe and the outlet NOx concentration field

[0070] This correlation is mainly reflected in the fact that the NOx concentration at the corresponding sampling port changes most significantly after the opening degree of the ammonia injection branch pipe at the denitrification inlet. Multiple opening degree adjustment tests were performed on each of the 36 ammonia injection branch pipes of the reactor, and the results were recorded. For example, the switch on / off of the A11 ammonia injection branch pipe had the greatest impact on the A23 sampling port of the two-dimensional sampling grid. The corresponding relationship is shown in Table 1 below:

[0071] Table 1

[0072]

[0073] II. Inter-block adjustments

[0074] Inter-block adjustment refers to aligning the average NOx concentrations of blocks A and B. Let A be the average NOx concentration of all samples from block A and B be the average NOx concentration of all samples from block B. Calculate the maximum deviation |AB| between the average concentrations of each block. When the deviation |AB| is too large (e.g., a high limit of 5 mg / m³ can be set), the maximum deviation is considered significant. 3 Initiate block adjustment measures (either 1 or 2, choose one): 1. Increase the opening of all ammonia injection branch valves in blocks with higher average NOx concentrations by 2%; 2. Decrease the opening of all ammonia injection branch valves in blocks with lower average NOx concentrations by 2%. Continue adjusting until the deviation |AB| meets the limit requirements, then proceed to internal adjustment within the block.

[0075] III. Internal Adjustments of Partition Blocks

[0076] Adjusting within a partition refers to aligning the average NOx concentration within each partition with the same level.

[0077] 1. Check the concentration field of the partition blocks and determine which partition blocks to adjust. The coefficient of variation (Cv) values ​​of the uniformity of partition blocks A and B are 50% and 25% respectively. The Cv value of partition block A is greater than the limit (e.g., the upper limit can be set to 30%), so the partition block A check procedure is started.

[0078] 2. Determine the adjustment target. The average value of all sample gases in Block A is 40 mg / m³. 3 The highest sample gas concentration was 55 mg / m³. 3 The minimum sample gas concentration is 30 mg / m³. 3 Due to the high concentration of the sample gas deviating from the mean by 15 mg / m³ 3 The low concentration sample gas deviated from the mean by 10 mg / m³ 3 Therefore, the adjustment target was determined to be the high-concentration sample gas with a larger deviation.

[0079] 3. Determine the adjustment area. Locate the branch with the highest NOx concentration in the transverse sample gas, A2j, at 55 mg / m. 3 The highest NOx concentration in the longitudinal sample gas branch was found to be 50 mg / m³ (Ai3). 3 At this point, the location confirms that sampling port A23 is the sampling area with the highest NOx concentration in block A.

[0080] 4. Adjustment. Based on the relationship between the opening of the ammonia injection branch pipe and the outlet NOx concentration field (determined in step 1), adjust the ammonia injection rate of branch pipe A11 in the corresponding area of ​​A23 to control the NOx concentration in area A23 to the average range, thereby reducing the unevenness of the denitrification reaction. The NOx concentration deviation at the A23 sampling port is (55-40) + (50-40) = 25 mg / m³. 3 By opening the valve of the ammonia injection branch pipe A11 to 50% according to the corresponding relationship, the NOx concentration can be brought to near the average value range.

[0081] 5. After adjustment, continue to check the concentration field of the partition blocks. The Cv value of partition block A is 22%, which meets the limit requirement. The internal consistency adjustment of the partition block is completed.

[0082] After adjustment, purge all sampling branch pipes. Shut off the sample gas supply to the analyzer gas line, fully close all branch pipe sampling electric valves, open the instrument gas purging main valve, and open each branch pipe sampling electric valve one by one, purging for 15 seconds and then closing. After purging, restore normal flue gas sampling mode.

[0083] In summary, this application collects NOx concentration distribution information at the denitrification outlet sampling section by setting up sampling branches in both horizontal and vertical dimensions, and quickly locates areas of excessive ammonia injection. Under the premise of reasonable cost and timely and effective control, it improves the operational efficiency of cyclic sampling. Furthermore, it determines the NOx concentration changes in the corresponding outlet area after adjusting the opening degree of each ammonia injection branch, providing a foundation for intelligent adjustment and precise ammonia injection in denitrification.

Claims

1. A method for automatic adjustment of ammonia injection for denitrification based on a two-dimensional sampling grid, characterized in that, include: S1. Divide the sampling area into multiple partition blocks, each partition block including multiple horizontal sampling branches and multiple vertical sampling branches with sampling ports; S2. Check the concentration field of the partition blocks to identify all partition blocks that need adjustment; S3. In the partition blocks that need to be adjusted, determine whether the adjustment target is a high-concentration area or a low-concentration area; S4. Determine the corresponding sampling port based on the adjustment target; S5. Based on the sampling port determined in S4, adjust the ammonia injection rate of the corresponding ammonia injection branch pipe. In S2, the NOx concentration in the sample gas from the transverse and longitudinal sampling branches is extracted and recorded sequentially. The coefficient of variation (Cv) reflecting the uniformity of the NOx concentration field at the outlet is calculated. When the Cv value is greater than a set threshold, the block is determined to be the block that needs adjustment. The formula for calculating the Cv value is: in, The number of measurement points, These are the measured values ​​at each measuring point. This is the average value of all measuring points; In S3, record the average NOx concentration A of all sample gases; record the highest NOx concentration Amax and the lowest NOx concentration Amin, and compare the absolute values ​​of their deviations from the average value |A-Amax| and |A-Amin|, with the larger one being the adjustment target; In S4, when the target is a high-concentration area, the branch pipe with the highest horizontal NOx concentration and the branch pipe with the highest vertical NOx concentration are found, and the sampling port at the intersection of the two branches is determined as the sampling area with the highest concentration in the partition block; when the target is a low-concentration area, the branch pipe with the lowest horizontal NOx concentration and the branch pipe with the lowest vertical NOx concentration are found, and the sampling port at the intersection of the two branches is determined as the sampling area with the lowest concentration in the partition block.

2. The automatic adjustment method for ammonia injection in denitrification based on a two-dimensional sampling grid according to claim 1, characterized in that, Also includes: S6. After adjustment, purge each sampling branch tube.

3. An automatic ammonia injection adjustment device for denitrification based on a two-dimensional sampling grid, characterized in that, The method for automatically adjusting ammonia injection for denitrification based on a two-dimensional sampling grid according to any one of claims 1 to 2 includes: a two-dimensional sampling grid, a denitrification purging device, a denitrification flue gas analyzer, a main pipe, and an electric valve. The two-dimensional sampling grid includes a transverse sampling grid and a longitudinal sampling grid. The transverse sampling grid includes multiple transverse sampling branches, and the longitudinal sampling grid includes multiple longitudinal sampling branches. Both the transverse and longitudinal sampling branches have multiple sampling ports, and there is a corresponding relationship between the sampling ports on the transverse and longitudinal sampling branches.

4. The automatic ammonia injection adjustment device for denitrification based on a two-dimensional sampling grid according to claim 3, characterized in that, The transverse sampling branch and the longitudinal sampling branch are connected to the main pipe through corresponding electric valves, and the main pipe is connected to the denitrification flue gas analyzer.

5. The automatic ammonia injection adjustment device for denitrification based on a two-dimensional sampling grid according to claim 4, characterized in that, The main pipe is also connected to the denitrification purging device.

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