Ammonia escape control method for SCR denitration system

Abstract

This invention relates to the field of pollutant control and discloses a method for controlling ammonia slip in an SCR denitrification system. The method includes: acquiring the denitrification operating conditions of multiple denitrification chambers through an online ammonia slip monitoring system, and determining the denitrification chambers to be investigated based on the analysis of these conditions. After detecting the ammonia slip concentration in each chamber to be investigated using a mobile monitoring device, target denitrification chambers are selected. For each target denitrification chamber, a corresponding checklist is constructed based on one or more of the following: the opening degree of the spray valve, the nitrogen oxide concentration at the flue gas inlet, the nitrogen oxide concentration at the flue gas outlet, the real-time ammonia slip concentration, and maintenance records. This checklist guides maintenance personnel in conducting targeted inspections and adjustments. After a preset time period, a retest is performed, and an ammonia slip control effect report is generated to evaluate the adjustment effect and optimize the denitrification system. This achieves precise control of ammonia slip.

Description

Technical Field

[0001] This invention relates to the field of pollutant control, and specifically to a method for controlling ammonia slip in an SCR denitrification system. Background Technology

[0002] Coke oven production generates harmful substances such as nitrogen oxides. To reduce the emission of these substances in coke oven flue gas, SCR (Selective Catalytic Reduction) denitrification systems are used in actual projects. Ammonia slip is one of the important parameters for assessing the normal operation of the denitrification system.

[0003] The main factors causing excessive ammonia slip in denitrification units are as follows:

[0004] (1) The ammonia flow rate of each ammonia spray gun is unevenly distributed, there is uneven local distribution of ammonia in the flue gas, the flue gas velocity is uneven, the amount of ammonia sprayed at the outlet of each spray gun is significantly different, and the ammonia escape is relatively higher in areas with higher concentration.

[0005] (2) The nitrogen oxide distribution at the inlet of the denitrification chamber is uneven and does not match the ammonia injection amount of the corresponding ammonia injection grid nozzle. The ammonia injection amount is relatively too large, resulting in high local ammonia escape.

[0006] (3) Catalyst blockage leads to a decrease in denitrification efficiency. In order to keep environmental parameters within limits, more ammonia will be sprayed, which will cause a vicious cycle. Local blockage and aging of the catalyst result in different catalytic efficiencies at different parts of the catalyst. In order to control the outlet parameters, the amount of ammonia sprayed can only be increased, which leads to an increase in local ammonia escape.

[0007] (4) Poor atomization of the spray gun nozzle, affected by ammonia water impurities, the impurities clog the nozzle, and the ammonia gas and flue gas cannot be fully mixed, resulting in a large amount of ammonia escape.

[0008] (5) When combustion fluctuates, the concentration of nitrogen oxides in the flue gas fluctuates greatly, which often leads to an increase in the amount of ammonia injected to mechanically achieve "emission compliance". Excessive ammonia injection can lead to an increase in ammonia escape.

[0009] (6) The concentration of ammonia solution is also an important factor affecting ammonia escape. If the concentration of ammonia solution is not properly prepared, too high or too low concentration may lead to ammonia escape.

[0010] (7) Reaction temperature is one of the key factors affecting ammonia escape. When the reaction temperature is too low, the reaction rate between nitrogen oxides and ammonia will decrease, which will cause a large amount of NH3 to escape without participating in the reaction. Therefore, controlling the reaction temperature within a suitable range is an important means to reduce ammonia escape.

[0011] Existing stockout systems often suffer from the following technical problems:

[0012] First, existing technologies lack effective real-time monitoring and analysis tools, making it impossible to accurately determine which denitrification chambers need to be inspected. Furthermore, traditional inspection and adjustment methods are usually rather crude, making it difficult to achieve refined management and efficient ammonia escape control. In addition, the failure to conduct effective effect retesting after adjustments also makes it impossible to discover potential problems or optimization solutions in a timely manner, thereby affecting the overall denitrification efficiency and environmental compliance of the denitrification system.

[0013] Second, existing technologies typically employ uniform detection and processing methods, which cannot accurately diagnose and differentiate the characteristics of denitrification chambers with different ammonia injection flow rates. This results in low resource utilization efficiency and inaccurate problem localization, which in turn affects the precise control of ammonia escape and the overall control efficiency, ultimately reducing the diagnostic and adjustment efficiency of the denitrification system.

[0014] Third, existing technologies cannot achieve dynamic identification and targeted adjustment of abnormal reaction temperatures, thus failing to effectively control ammonia escape concentration and reducing the reliability and environmental performance of the denitrification system. Summary of the Invention

[0015] The summary section of this invention provides a brief overview of the concepts, which will be described in detail in the detailed description section below. This summary section is not intended to identify key or essential features of the claimed technical solutions, nor is it intended to limit the scope of the claimed technical solutions.

[0016] This invention proposes a method for controlling ammonia slip in an SCR denitrification system to solve one or more of the technical problems mentioned in the background section above.

[0017] This invention provides a method for controlling ammonia slip in an SCR denitrification system, comprising: acquiring the denitrification operating conditions corresponding to each of multiple denitrification chambers through an online ammonia slip monitoring system; and jointly analyzing the denitrification operating conditions corresponding to multiple denitrification chambers to determine at least one denitrification chamber to be investigated from the multiple denitrification chambers.

[0018] Using a mobile ammonia slip monitoring device, the ammonia slip concentration of each of the at least one denitrification chambers to be investigated is detected to obtain the real-time ammonia slip concentration of each chamber. If the real-time ammonia slip concentration is greater than the preset ammonia slip concentration threshold, the corresponding denitrification chamber is identified as the target denitrification chamber, thus obtaining the target denitrification chamber group.

[0019] For each target denitrification chamber in the target denitrification chamber group, a corresponding checklist is constructed based on one or more of the following: the opening degree of the spray valve, the concentration of nitrogen oxides at the flue gas inlet, the concentration of nitrogen oxides at the flue gas outlet, the real-time ammonia escape concentration, and the maintenance record. The checklist includes multiple check items so that maintenance personnel can check and adjust the SCR denitrification system according to the multiple check items in the checklist.

[0020] After a preset time period, the ammonia slip concentration of each target denitrification chamber after adjustment is retested to obtain the retested ammonia slip concentration for each target denitrification chamber. Based on the retested ammonia slip concentration, an ammonia slip control effect report is generated.

[0021] Optionally, a joint analysis of the denitrification operating conditions corresponding to multiple denitrification chambers is performed to identify at least one denitrification chamber to be investigated from among the multiple denitrification chambers, including:

[0022] The nitrogen oxide concentration at the flue gas inlet is extracted from the denitrification operation to obtain the nitrogen oxide concentration at the flue gas inlet corresponding to each denitrification chamber; the standard nitrogen oxide concentration at the flue gas inlet is determined according to the current coke oven production load, which is either full production or reduced production.

[0023] Based on the corresponding nitrogen oxide concentration at the flue gas inlet and the standard nitrogen oxide concentration at the flue gas inlet, determine the nitrogen oxide exceedance status at the inlet of each denitrification chamber, the proportion of denitrification chambers exceeding the standard among multiple denitrification chambers, and the average nitrogen oxide concentration at the flue gas inlet; if the proportion of denitrification chambers exceeding the standard is greater than the preset proportion value, then the current working load of the exhaust gas return fan is continuously adjusted according to the average nitrogen oxide concentration at the flue gas inlet until the recalculated proportion of denitrification chambers exceeding the standard is less than or equal to the preset proportion value;

[0024] The actual ammonia escape concentration is extracted from the denitrification operation, and the denitrification chambers with actual ammonia escape concentration greater than the preset escape concentration are identified as denitrification chambers to be investigated, thus obtaining at least one denitrification chamber to be investigated.

[0025] Optionally, for each target denitrification chamber in the target denitrification chamber group, a corresponding inspection checklist is constructed based on one or more of the following: the opening degree of the spray valve, the nitrogen oxide concentration at the flue gas inlet, the nitrogen oxide concentration at the flue gas outlet, the real-time ammonia slip concentration, and maintenance records. This checklist includes:

[0026] For each target denitrification chamber, determine the opening degree of the spray valve on the ammonia injection grid branch pipe. If the spray valve opening degree is greater than the first set opening degree, the corresponding target denitrification chamber is determined as a high-flow ammonia denitrification chamber. If the spray valve opening degree is less than the second set opening degree, the corresponding target denitrification chamber is determined as a low-flow ammonia denitrification chamber. If the spray valve opening degree is greater than the second set opening degree and less than the first set opening degree, the corresponding target denitrification chamber is determined as a medium-flow ammonia denitrification chamber.

[0027] For a high-flow-rate ammonia denitrification chamber, the first nitrogen oxide concentration data corresponding to the first detection port and the second nitrogen oxide concentration data corresponding to the second detection port are extracted from the denitrification operating conditions. The first nitrogen oxide concentration data includes the nitrogen oxide concentration at the first flue gas inlet and the first flue gas outlet, and the second nitrogen oxide concentration data includes the nitrogen oxide concentration at the second flue gas inlet and the second flue gas outlet. Based on the nitrogen oxide concentrations at the first flue gas inlet and the first flue gas outlet, the first denitrification efficiency corresponding to the first detection port is calculated. Based on the nitrogen oxide concentrations at the second flue gas inlet and the second flue gas outlet, the second denitrification efficiency corresponding to the second detection port is calculated. If the difference between the first and second denitrification efficiencies is greater than a preset difference threshold, the first type of inspection item in the candidate inspection item set is included in the corresponding inspection list. Each inspection item in the candidate inspection item set is configured with multiple attribute information, including category number, introduction conditions, independence identifier, and associated inspection items. The first type of inspection item represents the inspection and adjustment of the denitrification uniformity of the denitrification chamber.

[0028] Optionally, for each target denitrification chamber in the target denitrification chamber group, a corresponding checklist is constructed based on one or more of the following: the opening degree of the spray valve, the nitrogen oxide concentration at the flue gas inlet, the nitrogen oxide concentration at the flue gas outlet, the real-time ammonia slip concentration, and maintenance records. This checklist also includes:

[0029] For a high-flow-rate ammonia denitrification chamber, if the difference between the first denitrification efficiency and the second denitrification efficiency is less than or equal to a preset difference threshold, the average denitrification efficiency is determined based on the first and second denitrification efficiencies, and the average denitrification efficiency is compared with the benchmark denitrification efficiency. If the average denitrification efficiency is less than the benchmark denitrification efficiency, the second type of inspection items in the candidate inspection item set are included in the corresponding inspection list. The second type of inspection items represents the inspection and adjustment of the flue gas outlet valve or flue gas inlet valve of the denitrification chamber.

[0030] Optionally, for each target denitrification chamber in the target denitrification chamber group, a corresponding checklist is constructed based on one or more of the following: the opening degree of the spray valve, the nitrogen oxide concentration at the flue gas inlet, the nitrogen oxide concentration at the flue gas outlet, the real-time ammonia slip concentration, and maintenance records. This checklist also includes:

[0031] For medium-flow or low-flow ammonia denitrification chambers, calculate the actual ratio of the spray valve opening to the nitrogen oxide concentration at the flue gas inlet. If the actual ratio is greater than the preset ratio, add one of the third-category inspection items from the candidate inspection item set to the corresponding inspection list. The third-category inspection item indicates that the spray valve opening on the ammonia injection grid branch pipe is checked and adjusted to reduce the ammonia flow rate. Track the ammonia escape concentration and the nitrogen oxide concentration at the flue gas outlet after reducing the ammonia flow rate to obtain the trend of ammonia escape concentration and the trend of nitrogen oxide concentration at the flue gas outlet.

[0032] Based on the independence identifier, determine whether each Category 3 inspection item in the inspection list is an independent inspection item; if it is not an independent inspection item, query at least one associated inspection item of the Category 3 inspection item in the inspection list and the introduction conditions of each associated inspection item.

[0033] Based on the trends of ammonia escape concentration, nitrogen oxide concentration at flue gas outlet, and the introduction conditions of each associated inspection item, select the associated inspection items whose introduction conditions are met from at least one associated inspection item as target associated inspection items; and add the target associated inspection items to the corresponding inspection list.

[0034] Optionally, for each target denitrification chamber in the target denitrification chamber group, a corresponding checklist is constructed based on one or more of the following: the opening degree of the spray valve, the nitrogen oxide concentration at the flue gas inlet, the nitrogen oxide concentration at the flue gas outlet, the real-time ammonia slip concentration, and maintenance records. This checklist also includes:

[0035] If the third category of inspection items in the inspection list is an independent inspection item, then the ammonia slip control effect is determined based on the trend of ammonia slip concentration change and the trend of nitrogen oxide concentration change at the flue gas outlet. If the ammonia slip control effect is not met, the most recent implementation time and standard maintenance interval of each inspection item are determined by querying maintenance records within the historical time period. Inspection items whose time interval between the most recent implementation time and the current time is greater than the standard maintenance interval are included in the corresponding inspection list.

[0036] Optionally, the ammonia slip control method for an SCR denitrification system of the present invention further includes:

[0037] For each target denitrification chamber in the target denitrification chamber group, obtain the dust concentration at the flue gas inlet and the dust concentration at the flue gas outlet from the denitrification operating conditions; calculate the difference between the dust concentration at the flue gas inlet and the dust concentration at the flue gas outlet, and compare the difference with the preset difference; if the difference is greater than or equal to the preset difference, then the fourth type of inspection item in the candidate inspection item set is included in the corresponding inspection list, where the fourth type of inspection item represents the inspection and adjustment of the dust collector bag damage.

[0038] The present invention has the following beneficial effects:

[0039] 1. This system achieves refined and effective control of ammonia slip, thereby improving the overall operating efficiency and environmental performance of the denitrification system. Specifically, the system acquires the denitrification operating conditions of multiple denitrification chambers through an online ammonia slip monitoring system, and identifies chambers to be investigated based on the analysis of these conditions. After detecting the ammonia slip concentration in each chamber using mobile monitoring equipment, target denitrification chambers are selected. For each target chamber, a corresponding checklist is constructed based on one or more of the following: spray valve opening, nitrogen oxide concentration at the flue gas inlet, nitrogen oxide concentration at the flue gas outlet, real-time ammonia slip concentration, and maintenance records. This checklist guides maintenance personnel in conducting targeted inspections and adjustments. After a preset time period, retesting is performed, and an ammonia slip control effect report is generated to evaluate the adjustment effect and optimize the denitrification system. Real-time monitoring, joint analysis, and screening of multiple denitrification chambers to identify target denitrification chambers enable rapid and accurate detection of ammonia slip concentration anomalies. It accurately locates the problematic ammonia escape chambers, reducing the blind investigation and repeated adjustments required in traditional methods. This enables precise and effective control of ammonia escape and improves the overall operating efficiency and environmental performance of the denitrification system.

[0040] 2. Improved overall control efficiency of ammonia slip and enhanced diagnostic and adjustment efficiency of the denitrification system. Specifically, for the target denitrification chamber group, the chambers were classified into high-flow, medium-flow, and low-flow ammonia denitrification chambers based on the opening degree of the spray valves. For high-flow denitrification chambers, nitrogen oxide concentration data corresponding to multiple detection ports were extracted, and the denitrification efficiency difference was calculated. If the efficiency difference exceeded the threshold, it was identified as a first-category inspection item and included in the inspection list. If the efficiency difference was within the threshold, the average denitrification efficiency was calculated and compared with the benchmark efficiency. If it was lower than the benchmark, it was identified as a second-category inspection item and included in the inspection list. For medium-flow or low-flow denitrification chambers, the actual ratio of the spray valve opening to the nitrogen oxide concentration at the flue gas inlet was calculated and compared with the preset ratio. If the actual ratio was too high, it was identified as a third-category inspection item and included in the inspection list. The trend of the adjusted ammonia slip concentration and the nitrogen oxide concentration at the flue gas outlet was tracked. Based on these trends and the conditions of the relevant inspection items, the target inspection items to be executed were selected and included in the inspection list. By using graded testing and differentiated checklists, combined with dynamic operating condition analysis, ammonia escape can be precisely controlled in a targeted manner. This not only improves the overall control efficiency of ammonia escape, but also enhances the diagnostic and adjustment efficiency of the denitrification system.

[0041] 3. Precise control of ammonia slip concentration improves the reliability and environmental performance of the denitrification system. Specifically, firstly, the reaction temperature data of each denitrification chamber is extracted from the denitrification operation and compared with the standard reaction temperature range to identify low-temperature or high-temperature anomalies, and the corresponding temperature deviation values ​​are calculated. Then, the heating intensity mode of the hot blast stove is generated based on the low-temperature deviation value, and the combustion parameters of the coke oven are adjusted based on the high-temperature deviation value. Finally, the inspection items and adjustment measures corresponding to the anomaly types are included in the inspection checklist. Low-temperature anomalies correspond to the inspection and adjustment of the hot blast stove, and high-temperature anomalies correspond to the inspection and adjustment of the coke oven combustion parameters. This achieves precise control of the catalyst reaction temperature, thereby precisely controlling the ammonia slip concentration and improving the reliability and environmental performance of the denitrification system. Attached Figure Description

[0042] The above and other features, advantages, and aspects of the various embodiments of the present invention will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and elements are not necessarily drawn to scale.

[0043] Figure 1 This is a flowchart of an ammonia slip control method for an SCR denitrification system according to the present invention;

[0044] Figure 2 This is an exemplary structural diagram of an SCR denitrification system, which is a method for controlling ammonia slip in an SCR denitrification system according to the present invention. Detailed Implementation

[0045] The invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the invention. It should be understood that the drawings and embodiments of the invention are for illustrative purposes only and are not intended to limit the scope of protection of the invention.

[0046] It should also be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0047] It should be noted that the concepts of "first" and "second" mentioned in this invention are only used to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0048] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0049] The names of messages or information exchanged between the various devices of this invention are for illustrative purposes only and are not intended to limit the scope of these messages or information.

[0050] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0051] like Figure 1 The diagram shows a flowchart of an ammonia slip control method for an SCR denitrification system according to the present invention, which specifically includes the following steps:

[0052] Step 101: Obtain the denitrification operating conditions of each denitrification chamber in multiple denitrification chambers through the ammonia escape online monitoring system; perform joint analysis on the denitrification operating conditions of multiple denitrification chambers to identify at least one denitrification chamber to be investigated from multiple denitrification chambers.

[0053] In some embodiments, the ammonia slip online monitoring system is used to monitor the denitrification status of the denitrification chamber in real time. The ammonia slip online monitoring system can be a backend server. The denitrification chamber refers to a single processing unit in an SCR (Selective Catalytic Reduction) denitrification system used for the reduction of nitrogen oxides. SCR denitrification systems are a widely used nitrogen oxide emission reduction technology in industrial fields, such as... Figure 2 As shown, the SCR denitrification system includes a denitrification chamber and a coke oven chimney. Each denitrification chamber typically includes a catalyst, reaction zone, and airflow control equipment, with the aim of converting nitrogen oxides in the exhaust gas into nitrogen and water vapor. The denitrification operating condition refers to the status information of the denitrification chamber during operation. This includes multiple denitrification chamber numbers, the nitrogen oxide concentration corresponding to each chamber number, and the initial ammonia slip concentration corresponding to each chamber number. Based on this, firstly, operating condition data for each denitrification chamber is continuously collected using sensors corresponding to each chamber. Then, the sensors establish a communication connection with the ammonia slip online monitoring system, transmitting the operating condition data to the system. Based on this, statistical analysis is performed on the denitrification operating conditions of multiple chambers to identify anomalies, and the chambers with anomalies are marked as chambers to be investigated. As an example, the denitrification conditions of 7 denitrification chambers were obtained through the online ammonia escape monitoring system. The nitrogen oxide concentration and actual ammonia escape concentration at the flue gas inlet of each denitrification chamber were analyzed, and 4 abnormal denitrification chambers were identified. These 4 abnormal denitrification chambers were marked as denitrification chambers to be investigated.

[0054] Step 102: Using an ammonia slip mobile monitoring device, the ammonia slip concentration of each of the at least one denitrification chambers to be investigated is detected to obtain the real-time ammonia slip concentration of each chamber. If the real-time ammonia slip concentration is greater than the preset ammonia slip concentration threshold, the corresponding denitrification chamber to be investigated is determined as the target denitrification chamber, thus obtaining the target denitrification chamber group.

[0055] In some embodiments, the ammonia slip mobile monitoring device is a portable monitoring device used to accurately measure the ammonia slip concentration in denitrification chambers. The ammonia slip mobile monitoring device includes a sensor module and a data processing module. Based on this, according to the denitrification chambers to be investigated as determined by the online ammonia slip monitoring system, measurement points are set at key locations in each chamber. The ammonia concentration values ​​at these measurement points are collected multiple times by the sensor module, and the average ammonia concentration is calculated by the data processing module to obtain the real-time ammonia slip concentration for each chamber. The real-time ammonia slip concentration refers to the ammonia concentration data directly measured on-site by the ammonia slip mobile monitoring device. The preset ammonia slip concentration threshold refers to the maximum permissible ammonia slip concentration value set according to the denitrification system operation specifications or environmental standards. Based on this, the real-time ammonia slip concentration of each chamber to be investigated is compared with the preset ammonia slip concentration threshold. Chambers with real-time ammonia slip concentrations greater than the preset threshold are marked as target denitrification chambers. All target denitrification chambers are summarized to form a target denitrification chamber group. In this context, a target denitrification chamber refers to a denitrification chamber where the real-time ammonia slip concentration exceeds a preset ammonia slip concentration threshold. A target denitrification chamber group is a collection of all target denitrification chambers, including multiple chamber numbers. For example, a factory has five denitrification chambers (numbered A, B, C, D, and E). Mobile ammonia slip monitoring equipment is used to monitor each chamber individually, obtaining the real-time ammonia slip concentration for each. The monitoring data are as follows: Chamber A's real-time ammonia slip concentration is 20 ppm; Chamber B's is 45 ppm; Chamber C's is 60 ppm; Chamber D's is 25 ppm; and Chamber E's is 75 ppm. The preset ammonia slip concentration threshold is 50 ppm. By comparing the real-time ammonia escape concentration with the threshold, the chambers with ammonia escape concentration greater than the preset threshold are identified as chamber C and chamber E. Chambers C and E are then identified as target denitrification chambers and combined to form a target denitrification chamber group.

[0056] Step 103: For each target denitrification chamber in the target denitrification chamber group, construct a corresponding checklist based on one or more of the following: the opening degree of the spray valve, the concentration of nitrogen oxides at the flue gas inlet, the concentration of nitrogen oxides at the flue gas outlet, the real-time ammonia escape concentration, and the maintenance record. The checklist includes multiple check items so that maintenance personnel can inspect and adjust the SCR denitrification system according to the multiple check items in the checklist.

[0057] In some embodiments, based on the denitrification chamber number corresponding to each target denitrification chamber, the opening degree of the spray valve, the nitrogen oxide concentration at the flue gas inlet, and the nitrogen oxide concentration at the flue gas outlet of the corresponding target denitrification chamber are retrieved during the denitrification operation. The spray valve opening degree refers to the size of the valve opening controlling the ammonia flow rate on the ammonia injection grid branch pipe. The nitrogen oxide concentration at the flue gas inlet refers to the concentration of nitrogen oxides in the flue gas before entering the target denitrification chamber. The nitrogen oxide concentration at the flue gas outlet refers to the concentration of nitrogen oxides in the flue gas after passing through the target denitrification chamber. The maintenance records of the target denitrification chamber are retrieved from the maintenance database. The maintenance database includes the denitrification chamber number and maintenance records. The maintenance records include the equipment's maintenance history, equipment operating status, the time of the most recent maintenance, known faults, etc. By analyzing the spray valve opening degree, the nitrogen oxide concentration at the flue gas inlet, the nitrogen oxide concentration at the flue gas outlet, one or more items from the maintenance records, and the real-time ammonia escape concentration, a preliminary diagnostic result of the denitrification chamber's operating status is obtained. Based on the preliminary diagnostic results, potential problems are identified and corresponding inspection items are compiled into a checklist. This checklist serves as a detailed operational guide for the maintenance personnel at the inspection terminals, including key items requiring investigation and adjustment within the target denitrification chamber. The checklist is then distributed to the maintenance personnel at the respective terminals. The personnel then systematically check the target denitrification chamber against the checklist, addressing any issues found through adjustments or repairs.

[0058] Step 104: After a preset time period, the ammonia slip concentration of each target denitrification chamber is retested to obtain the retested ammonia slip concentration for each target denitrification chamber. Based on the retested ammonia slip concentration, an ammonia slip control effect report is generated.

[0059] In some embodiments, the preset duration refers to a set time period after adjusting the working state of the denitrification chamber. Based on this preset duration, after which the ammonia slip concentration of each target denitrification chamber is measured again using a mobile ammonia slip monitoring device, yielding a remeasured ammonia slip concentration for each target denitrification chamber. The remeasured ammonia slip concentration refers to re-measuring the ammonia slip concentration of the adjusted chamber using the ammonia slip concentration monitoring device. Based on the remeasured ammonia slip concentration, it is determined whether the standard has been met, and an ammonia slip control effect report is generated. This report is an analysis and summary of the adjusted ammonia slip concentration, including comparative analysis and evaluation of the adjustment effect.

[0060] These embodiments achieve refined and effective control of ammonia slip, thereby improving the overall operating efficiency and environmental performance of the denitrification system. Specifically, the denitrification conditions of multiple denitrification chambers are acquired through an online ammonia slip monitoring system, and the chambers to be investigated are determined based on the analysis of these conditions. After detecting the ammonia slip concentration in each chamber using mobile monitoring equipment, target denitrification chambers are selected. For each target chamber, a corresponding checklist is constructed based on one or more of the following: spray valve opening, nitrogen oxide concentration at the flue gas inlet, nitrogen oxide concentration at the flue gas outlet, real-time ammonia slip concentration, and maintenance records. This checklist guides maintenance personnel in conducting targeted inspections and adjustments. After a preset time period, retesting is performed, and an ammonia slip control effect report is generated to evaluate the adjustment effect and optimize the denitrification system. Real-time monitoring, joint analysis, and screening of multiple denitrification chambers to identify target denitrification chambers enable rapid and accurate detection of ammonia slip concentration anomalies. It accurately locates the problematic ammonia escape chambers, reducing the blind investigation and repeated adjustments required in traditional methods. This enables precise and effective control of ammonia escape and improves the overall operating efficiency and environmental performance of the denitrification system.

[0061] In some embodiments, to further address the second technical problem described in the background section, namely, "existing technologies typically employ uniform detection and processing methods, which cannot accurately diagnose and differentiate the characteristics of denitrification chambers with different ammonia injection flow rates, resulting in low resource utilization efficiency and inaccurate problem localization, thereby affecting the precise control of ammonia escape and overall control efficiency, ultimately reducing the diagnostic and adjustment efficiency of the denitrification system," some embodiments of the present invention perform joint analysis of the denitrification operating conditions corresponding to multiple denitrification chambers to determine at least one denitrification chamber to be investigated from multiple denitrification chambers, including:

[0062] Step 1: Extract the nitrogen oxide concentration at the flue gas inlet from the denitrification operating conditions to obtain the nitrogen oxide concentration at the flue gas inlet corresponding to each denitrification chamber; determine the standard nitrogen oxide concentration at the flue gas inlet based on the current coke oven production load conditions, which are either full production or reduced production.

[0063] In some embodiments, sensors corresponding to each denitrification chamber continuously collect the nitrogen oxide concentration at the flue gas inlet of each denitrification chamber. The collected nitrogen oxide concentration at the flue gas inlet is transmitted to an online ammonia slip monitoring system, which processes the raw data. Based on this, each denitrification chamber is assigned a denitrification chamber number, and the processed nitrogen oxide concentration data is then categorized according to the denitrification chamber number and integrated into the denitrification operating conditions. The denitrification operating conditions can be stored in a database. Based on this, the "nitrogen oxide concentration at the inlet" field is queried from the denitrification operating conditions to obtain the nitrogen oxide concentration at the flue gas inlet corresponding to each denitrification chamber. The current coke oven production load condition is obtained from the coke oven operating status information. The coke oven production load condition describes the load status of the coke oven operation, which is either full production or reduced production. The coke oven operating status information includes the current coke oven production load condition. In practice, when the coke oven is operating at full capacity, the standard nitrogen oxide concentration at the flue gas inlet corresponding to full capacity is retrieved from the historical coke oven operation database. When the coke oven is operating at reduced capacity, the first standard concentration is adjusted according to the reduction ratio to obtain the standard nitrogen oxide concentration at the flue gas inlet corresponding to the reduced capacity. The standard nitrogen oxide concentration at the flue gas inlet is a reference value for the nitrogen oxide concentration at the flue gas inlet under a specific coke oven production load condition. The historical coke oven operation database includes coke oven production load conditions and corresponding standard nitrogen oxide concentrations at the flue gas inlet. As an example, the historical database includes a standard nitrogen oxide concentration of 350 mg / m³ at full capacity and 280 mg / m³ at a reduction ratio of 80%.

[0064] Step 2: Based on the corresponding nitrogen oxide concentration at the flue gas inlet and the standard nitrogen oxide concentration at the flue gas inlet, determine the nitrogen oxide exceedance status at the inlet of each denitrification chamber, the proportion of denitrification chambers exceeding the standard among multiple denitrification chambers, and the average nitrogen oxide concentration at the flue gas inlet; if the proportion of denitrification chambers exceeding the standard is greater than the preset proportion value, then the current working load of the exhaust gas return fan is continuously adjusted according to the average nitrogen oxide concentration at the flue gas inlet until the recalculated proportion of denitrification chambers exceeding the standard is less than or equal to the preset proportion value.

[0065] In some embodiments, for each denitrification chamber, the nitrogen oxide concentration at the flue gas inlet is compared with the standard nitrogen oxide concentration at the flue gas inlet to determine the nitrogen oxide exceedance status at the flue gas inlet of the corresponding denitrification chamber. The exceedance status is defined as either exceeding the standard or normal. If the nitrogen oxide concentration at the flue gas inlet is greater than the standard concentration, the exceedance status is considered exceeding the standard; if the concentration is less than or equal to the standard concentration, the exceedance status is considered normal. Denitrification chambers with exceedance status at the flue gas inlet are identified as exceeding-standard denitrification chambers. The number of exceeding-standard denitrification chambers and the total number of denitrification chambers are counted separately. The number of exceeding-standard denitrification chambers is divided by the total number of denitrification chambers, and then multiplied by 100% to obtain the percentage of exceeding-standard denitrification chambers among the multiple denitrification chambers. The average nitrogen oxide concentration at the flue gas inlet is obtained by summing the nitrogen oxide concentrations at the flue gas inlet of all denitrification chambers and then dividing by the total number of denitrification chambers. The average nitrogen oxide concentration at the flue gas inlet refers to the average nitrogen oxide concentration at the flue gas inlet of all denitrification chambers. The preset percentage is a pre-defined threshold for the percentage of chambers exceeding the standard. Based on this, if the percentage of denitrification chambers exceeding the standard is greater than the preset percentage, the exhaust gas flow distribution needs to be changed by adjusting the workload of the exhaust gas return fan to reduce the exceedance. The exhaust gas return fan is used to control the amount of nitrogen oxides at the flue gas inlet. For example, a factory has 6 denitrification chambers (numbered A, B, C, D, E, and F). It is necessary to analyze the exceedance situation and adjust the workload of the exhaust gas return fan based on the nitrogen oxide concentration at the flue gas inlet and the standard nitrogen oxide concentration at the flue gas inlet. After detecting the nitrogen oxide concentration at the flue gas inlet of each denitrification chamber and comparing it with the standard nitrogen oxide concentration at the flue gas inlet, the denitrification chambers that exceed the standard are identified as A, C, and D. The number of denitrification chambers exceeding the standard is counted as 3, and the total number of denitrification chambers is counted as 6, resulting in an exceedance percentage of 50%. Then, the nitrogen oxide concentrations at the flue gas inlets of the six denitrification chambers are summed and divided by the total number of denitrification chambers to obtain the average nitrogen oxide concentration at the flue gas inlet. The preset exceedance percentage is 40%. If the current exceedance percentage is greater than the preset exceedance percentage, the average nitrogen oxide concentration at the flue gas inlet is compared with the preset average average nitrogen oxide concentration at the flue gas inlet to obtain the deviation value. Based on the deviation value, the corresponding fan adjustment coefficient is obtained from the preset fan adjustment coefficient table. The fan adjustment coefficient table includes the deviation range of the average nitrogen oxide concentration at the flue gas inlet and the corresponding fan adjustment direction and fan frequency. The current exhaust gas return fan's workload is continuously adjusted according to the fan adjustment coefficient. After adjustment, the nitrogen oxide concentration at the flue gas inlet is monitored again to determine whether further adjustment is needed until the exceedance percentage of denitrification chambers is less than or equal to the preset percentage value.

[0066] Step 3: Extract the actual ammonia escape concentration from the denitrification operating conditions, and identify the denitrification chambers with actual ammonia escape concentrations greater than the preset escape concentrations as denitrification chambers to be investigated, thus obtaining at least one denitrification chamber to be investigated.

[0067] In some embodiments, the preset escape concentration is a pre-set ammonia escape concentration threshold used to screen abnormal denitrification chambers. Based on this, the actual ammonia escape concentration is read from the denitrification operation using an online ammonia escape monitoring system, and the extracted actual ammonia escape concentration is compared with the preset escape concentration. If the actual ammonia escape concentration is greater than the preset threshold, the corresponding denitrification chamber is marked as a denitrification chamber to be investigated. At least one denitrification chamber is identified as a chamber to be investigated.

[0068] For each target denitrification chamber in the target denitrification chamber group, a corresponding inspection checklist is constructed based on one or more of the following: the opening degree of the spray valve, the nitrogen oxide concentration at the flue gas inlet, the nitrogen oxide concentration at the flue gas outlet, the real-time ammonia slip concentration, and maintenance records. This checklist includes:

[0069] Step 1: For each target denitrification chamber, determine the opening degree of the spray valve on the ammonia injection grid branch pipe. If the spray valve opening degree is greater than the first set opening degree, the corresponding target denitrification chamber is determined as a high-flow ammonia denitrification chamber. If the spray valve opening degree is less than the second set opening degree, the corresponding target denitrification chamber is determined as a low-flow ammonia denitrification chamber. If the spray valve opening degree is greater than the second set opening degree and less than the first set opening degree, the corresponding target denitrification chamber is determined as a medium-flow ammonia denitrification chamber.

[0070] In some embodiments, for each target denitrification chamber, the opening degree of the spray valve on the ammonia spraying grid branch pipe is compared with a set valve opening threshold to determine which type of flow rate denitrification chamber the corresponding target denitrification chamber belongs to. Here, the opening degree of the spray valve on the ammonia spraying grid branch pipe refers to the opening degree of the spray valve connected to the ammonia spraying grid branch pipe, controlling the ammonia flow rate. The opening degree of the spray valve (usually expressed as a percentage) directly affects the ammonia injection rate and ammonia slip concentration. The larger the valve opening, the more ammonia is injected. Here, the ammonia spraying grid branch pipe refers to the pipe connected to the spray valve and the ammonia spraying grid. The first set opening degree is a pre-set valve opening threshold, representing a standard for a larger ammonia flow rate. Based on this, if the spray valve opening degree is greater than the first set opening degree, the corresponding target denitrification chamber is marked as a high-flow ammonia denitrification chamber. Here, a high-flow ammonia denitrification chamber indicates that the denitrification chamber uses a larger ammonia flow rate for denitrification treatment. The second set opening degree is another set valve opening threshold, representing a standard for a smaller ammonia flow rate. Based on this, if the opening degree of the spraying valve is less than the second set opening degree, the corresponding target denitrification chamber is marked as a low-flow ammonia denitrification chamber. A low-flow ammonia denitrification chamber indicates that the denitrification chamber uses a relatively small flow rate of ammonia for denitrification. If the opening degree of the spraying valve is greater than the second set opening degree but less than the first set opening degree, the corresponding target denitrification chamber is marked as a medium-flow ammonia denitrification chamber. A medium-flow ammonia denitrification chamber indicates that the denitrification chamber uses a medium flow rate of ammonia.

[0071] Step 2: For the high-flow-rate ammonia denitrification chamber, extract the first nitrogen oxide concentration data corresponding to the first detection port and the second nitrogen oxide concentration data corresponding to the second detection port from the denitrification operating conditions. The first nitrogen oxide concentration data includes the nitrogen oxide concentration at the first flue gas inlet and the first flue gas outlet, and the second nitrogen oxide concentration data includes the nitrogen oxide concentration at the second flue gas inlet and the second flue gas outlet. Calculate the first denitrification efficiency corresponding to the first detection port based on the nitrogen oxide concentrations at the first flue gas inlet and the first flue gas outlet. Calculate the second denitrification efficiency corresponding to the second detection port based on the nitrogen oxide concentrations at the second flue gas inlet and the second flue gas outlet. If the difference between the first and second denitrification efficiencies is greater than a preset difference threshold, then the first type of inspection item in the candidate inspection item set is included in the corresponding inspection list. Each inspection item in the candidate inspection item set is configured with multiple attribute information, including category number, introduction conditions, independence identifier, and associated inspection items. The first type of inspection item represents the inspection and adjustment of the denitrification uniformity of the denitrification chamber.

[0072] In some embodiments, the first detection port and the second detection port are two monitoring locations set for the denitrification chamber, respectively, to detect the concentration of nitrogen oxides in the flue gas. The detected nitrogen oxide concentrations at the first and second detection ports are recorded in the denitrification operating conditions. The denitrification operating conditions also include the nitrogen oxide concentrations corresponding to the first and second detection ports. Based on this, for a high-flow-rate ammonia denitrification chamber, the denitrification chamber number corresponding to the high-flow-rate ammonia denitrification chamber is first determined. Based on the denitrification chamber number, the nitrogen oxide concentration data corresponding to the first and second detection ports are retrieved from the denitrification operating conditions to obtain the first and second nitrogen oxide concentration data. The first nitrogen oxide concentration data includes the nitrogen oxide concentration at the first flue gas inlet and the nitrogen oxide concentration at the first flue gas outlet, and the second nitrogen oxide concentration data includes the nitrogen oxide concentration at the second flue gas inlet and the nitrogen oxide concentration at the second flue gas outlet. The nitrogen oxide concentration at the first flue gas inlet refers to the nitrogen oxide concentration measured at the flue gas inlet of the first detection port in the denitrification chamber. The nitrogen oxide concentration at the first flue gas outlet refers to the nitrogen oxide concentration measured at the flue gas outlet of the first detection port in the denitrification chamber. The nitrogen oxide concentration at the second flue gas inlet refers to the nitrogen oxide concentration measured at the flue gas inlet of the second detection port in the denitrification chamber. The nitrogen oxide concentration at the second flue gas outlet refers to the nitrogen oxide concentration measured at the flue gas outlet of the second detection port in the denitrification chamber.

[0073] Based on this, the denitrification efficiency of the first detection port is calculated by comparing the nitrogen oxide concentration data at the flue gas inlet and outlet of the first detection port. Similarly, the denitrification efficiency of the second detection port is calculated by comparing the nitrogen oxide concentration data at the flue gas inlet and outlet of the second detection port. Denitrification efficiency refers to the effectiveness of the denitrification system in removing nitrogen oxides from flue gas, typically expressed as the ratio of the difference between the inlet and outlet nitrogen oxide concentrations to the inlet nitrogen oxide concentration. A higher denitrification efficiency indicates a better denitrification effect. A preset difference threshold is a system-defined value used to determine if the difference between denitrification efficiencies is large enough to require further investigation. Based on this, the difference between the first and second denitrification efficiencies is compared to determine if it exceeds the preset difference threshold. If the difference is greater than the threshold, the conditions for introducing the first type of inspection item in the candidate inspection item set are met, and the first type of inspection item in the candidate inspection item set is added to the inspection list. The first category of inspection items is used to characterize the need for maintenance personnel to check the uniformity of ammonia distribution in the denitrification chamber, and to make adjustments to inspection items that are confirmed to have abnormalities. Each inspection item in the candidate inspection item set is configured with multiple attribute information, including category number, introduction condition, independence identifier, and associated inspection items. The category number uniquely identifies each type of inspection item. The introduction condition describes the specific conditions that meet the inspection item. The independence identifier indicates whether the inspection item is associated with other inspection items. Associated inspection items describe other inspection tasks related to this item.

[0074] For each target denitrification chamber in the target denitrification chamber group, a corresponding inspection checklist is constructed based on one or more of the following: the opening degree of the spray valve, the nitrogen oxide concentration at the flue gas inlet, the nitrogen oxide concentration at the flue gas outlet, the real-time ammonia escape concentration, and maintenance records. This checklist also includes:

[0075] For a high-flow-rate ammonia denitrification chamber, if the difference between the first denitrification efficiency and the second denitrification efficiency is less than or equal to a preset difference threshold, the average denitrification efficiency is determined based on the first and second denitrification efficiencies, and the average denitrification efficiency is compared with the benchmark denitrification efficiency. If the average denitrification efficiency is less than the benchmark denitrification efficiency, the second type of inspection items in the candidate inspection item set are included in the corresponding inspection list. The second type of inspection items represents the inspection and adjustment of the flue gas outlet valve or flue gas inlet valve of the denitrification chamber.

[0076] In some embodiments, for a high-flow-rate ammonia denitrification chamber, if the difference between the first denitrification efficiency and the second denitrification efficiency is less than or equal to a preset difference threshold, the average of the first and second denitrification efficiencies is calculated to obtain the average denitrification efficiency. The average denitrification efficiency is then compared with a preset benchmark denitrification efficiency. When the average denitrification efficiency is lower than the benchmark denitrification efficiency, the conditions for introducing the second type of inspection item in the candidate inspection item set are met, and the second type of inspection item in the candidate inspection item set is included in the inspection list of the corresponding denitrification chamber. The benchmark denitrification efficiency is a preset target efficiency value, representing the ideal denitrification performance standard that the chamber should achieve. The second type of inspection item is an inspection of the flue gas outlet valve or flue gas inlet valve, used to characterize the need for maintenance personnel to check the valve's operating status (such as whether the opening is reasonable, whether there is blockage or leakage, etc.), and to make adjustments for inspection items where abnormalities are confirmed.

[0077] For each target denitrification chamber in the target denitrification chamber group, a corresponding inspection checklist is constructed based on one or more of the following: the opening degree of the spray valve, the nitrogen oxide concentration at the flue gas inlet, the nitrogen oxide concentration at the flue gas outlet, the real-time ammonia escape concentration, and maintenance records. This checklist also includes:

[0078] Step 1: For medium-flow or low-flow ammonia denitrification chambers, calculate the actual ratio of the spray valve opening to the nitrogen oxide concentration at the flue gas inlet. If the actual ratio is greater than the preset ratio, add one of the third-category inspection items from the candidate inspection item set to the corresponding inspection list. The third-category inspection item indicates that the spray valve opening on the ammonia injection grid branch pipe is checked and adjusted to reduce the ammonia flow rate. Track the ammonia escape concentration and the nitrogen oxide concentration at the flue gas outlet after reducing the ammonia flow rate to obtain the trend of ammonia escape concentration and the trend of nitrogen oxide concentration at the flue gas outlet.

[0079] In some embodiments, for medium-flow or low-flow ammonia denitrification chambers, the ratio of the spray valve opening to the nitrogen oxide concentration at the flue gas inlet is calculated to obtain the actual ratio. This actual ratio is used to assess the matching degree between the ammonia injection rate and the nitrogen oxide concentration in the flue gas. A preset ratio is a pre-defined threshold used to determine whether the spray valve opening is reasonable. Based on this, if the actual ratio is greater than the preset ratio, the conditions for introducing a third-category inspection item in the candidate inspection item set are met, and the third-category inspection item in the candidate inspection item set is included in the corresponding inspection list. This third-category inspection item is used to check whether the spray valve of the ammonia injection grid branch pipe has abnormal opening, blockage, mechanical failure, or other problems. The maintenance personnel at the maintenance terminal adjust the spray valve opening based on the inspection results to reduce the ammonia flow rate. After reducing the ammonia flow rate, the changes in ammonia slip concentration and nitrogen oxide concentration at the flue gas outlet are monitored at high frequency within the target time period. The monitored ammonia slip concentration and nitrogen oxide concentration data are timestamped and stored in a database. Data is extracted from the database, and the rate of change of concentration over time is calculated to obtain the trends in ammonia slip concentration and nitrogen oxide concentration at the flue gas outlet. The trend in ammonia slip concentration reflects the regularity of ammonia slip concentration changes over time. The trend in nitrogen oxide concentration at the flue gas outlet reflects the regularity of nitrogen oxide concentration changes over time at the flue gas outlet.

[0080] Step 2: Based on the independence identifier, determine whether each Category 3 inspection item in the inspection list is an independent inspection item; if it is not an independent inspection item, query at least one related inspection item of the Category 3 inspection item in the inspection list and the introduction conditions of each related inspection item.

[0081] In some embodiments, an independence identifier is identified for each third category of inspection item included in the checklist. If the identified independence identifier indicates that the item is not an independent inspection item, then at least one associated inspection item of the third category of inspection item included in the checklist and the introduction conditions of each associated inspection item are further queried.

[0082] Step 3: Based on the trends of ammonia escape concentration, nitrogen oxide concentration at flue gas outlet, and the introduction conditions of each associated inspection item, select the associated inspection items whose introduction conditions are met from at least one associated inspection item as target associated inspection items; add the target associated inspection items to the corresponding inspection list.

[0083] In some embodiments, the introductory conditions for associated inspection items are retrieved, and the corresponding introductory conditions are matched with the trends in ammonia slip concentration and nitrogen oxide concentration at the flue gas outlet. Associated inspection items that meet the introductory conditions are selected from at least one associated inspection item as target associated inspection items. The selected target associated inspection items are added to the inspection list.

[0084] For each target denitrification chamber in the target denitrification chamber group, a corresponding inspection checklist is constructed based on one or more of the following: the opening degree of the spray valve, the nitrogen oxide concentration at the flue gas inlet, the nitrogen oxide concentration at the flue gas outlet, the real-time ammonia escape concentration, and maintenance records. This checklist also includes:

[0085] If the third category of inspection items in the inspection list is an independent inspection item, then the ammonia slip control effect is determined based on the trend of ammonia slip concentration change and the trend of nitrogen oxide concentration change at the flue gas outlet. If the ammonia slip control effect is not met, the most recent implementation time and standard maintenance interval of each inspection item are determined by querying maintenance records within the historical time period. Inspection items whose time interval between the most recent implementation time and the current time is greater than the standard maintenance interval are included in the corresponding inspection list.

[0086] In some embodiments, the independence identifier of each Category 3 inspection item included in the inspection list is identified. If the identified independence identifier indicates that it is an independent inspection item, compliance judgment rules are set for the ammonia slip concentration and the nitrogen oxide concentration at the flue gas outlet, respectively. If the compliance judgment rules are met, the ammonia slip control effect is judged to be compliant. If the compliance judgment rules are not met, the ammonia slip control effect is judged to be non-compliant. For cases where the ammonia slip control effect is non-compliant, maintenance records within a historical time period are queried according to the category number corresponding to the current inspection item. These maintenance records are stored in a local database and include fields such as the category number of the inspection item, the most recent implementation time, and the result. Based on this, the "most recent implementation time" and "standard maintenance interval duration" fields are first extracted from the maintenance records within the historical time period to obtain the specific values ​​corresponding to the most recent implementation time and the standard maintenance interval duration. Then, the time interval between the most recent implementation time and the current time is calculated and compared with the standard maintenance interval duration. Inspection items with a time interval greater than the standard maintenance interval duration are filtered out and included in the inspection list.

[0087] The present invention provides a method for controlling ammonia slip in an SCR denitrification system, which further includes:

[0088] For each target denitrification chamber in the target denitrification chamber group, obtain the dust concentration at the flue gas inlet and the dust concentration at the flue gas outlet from the denitrification operating conditions; calculate the difference between the dust concentration at the flue gas inlet and the dust concentration at the flue gas outlet, and compare the difference with the preset difference; if the difference is greater than or equal to the preset difference, then the fourth type of inspection item in the candidate inspection item set is included in the corresponding inspection list, where the fourth type of inspection item represents the inspection and adjustment of the dust collector bag damage.

[0089] In some embodiments, dust concentration data is collected in real time by dust concentration sensors at the inlet and outlet, and a communication connection is established with the ammonia escape online monitoring system to transmit the dust concentration data. The ammonia escape online monitoring system categorizes the received dust concentration data according to the denitrification chamber number and stores it in the denitrification condition. Information corresponding to the "dust concentration at flue gas inlet" and "dust concentration at flue gas outlet" fields is read from the denitrification condition to obtain the dust concentration data at the flue gas inlet and outlet. The dust concentration at the flue gas inlet refers to the particulate matter concentration in the flue gas before entering the denitrification chamber. The dust concentration at the flue gas outlet refers to the particulate matter concentration in the flue gas after denitrification and dust removal treatment. The preset difference is a normal range of difference between the inlet and outlet dust concentrations set based on experience and experimental data. Based on this, the difference between the dust concentration at the flue gas inlet and the dust concentration at the flue gas outlet is first calculated. Then, the calculated difference is compared with the preset difference. If the difference is greater than or equal to the preset difference, the conditions for introducing the fourth type of inspection item in the candidate inspection item set are met, and the fourth type of inspection item in the candidate inspection item set is added to the inspection list. Among them, the fourth type of inspection item represents the inspection of the damage to the dust collector bags, and the replacement of the damaged dust collector bags.

[0090] These embodiments improve the overall control efficiency of ammonia slip and enhance the diagnostic and adjustment efficiency of the denitrification system. Specifically, for the target denitrification chamber group, the target denitrification chambers are classified into high-flow, medium-flow, and low-flow ammonia denitrification chambers based on the opening degree of the spray valve. For the high-flow denitrification chamber, nitrogen oxide concentration data corresponding to multiple detection ports are extracted, and the denitrification efficiency difference is calculated. If the efficiency difference exceeds a threshold, it is identified as a first-category inspection item and included in the inspection list. If the efficiency difference is within the threshold, the average denitrification efficiency is calculated and compared with the benchmark efficiency. If it is lower than the benchmark, it is identified as a second-category inspection item and included in the inspection list. For medium-flow or low-flow denitrification chambers, the actual ratio of the spray valve opening to the nitrogen oxide concentration at the flue gas inlet is calculated and compared with a preset ratio. If the actual ratio is too high, it is identified as a third-category inspection item and included in the inspection list. The trend of the adjusted ammonia slip concentration and the nitrogen oxide concentration at the flue gas outlet is tracked. Based on these trends and the conditions of the relevant inspection items, the target inspection items to be executed are selected and included in the inspection list. By using graded testing and differentiated checklists, combined with dynamic operating condition analysis, ammonia escape can be precisely controlled in a targeted manner. This not only improves the overall control efficiency of ammonia escape, but also enhances the diagnostic and adjustment efficiency of the denitrification system.

[0091] In some embodiments, to further address the third technical problem described in the background section, namely, "the existing technology cannot achieve dynamic identification and targeted adjustment of abnormal reaction temperatures, thus failing to effectively control ammonia escape concentration and reducing the reliability and environmental performance of the denitrification system," some embodiments of the present invention further include the following steps:

[0092] Step 1: For each target denitrification chamber in the target denitrification chamber group, extract the reaction temperature data from the denitrification operating conditions; based on the reaction temperature data and the standard reaction temperature range, determine the temperature anomaly, which is either a low temperature anomaly or a high temperature anomaly; if the temperature anomaly is a low temperature anomaly, generate a low temperature deviation value based on the minimum value of the standard reaction temperature range and the reaction temperature data; if the temperature anomaly is a high temperature anomaly, generate a high temperature deviation value based on the maximum value of the standard reaction temperature range and the reaction temperature data.

[0093] In some embodiments, temperature sensors corresponding to each denitrification chamber collect reaction temperature data in real time and transmit the data to an online ammonia slip monitoring system. The online ammonia slip monitoring system establishes a communication connection with the temperature sensors, receives the reaction temperature data, and integrates it into the denitrification operating condition. Based on the denitrification chamber number corresponding to the target denitrification chamber, the system searches for the reaction temperature data in the denitrification operating condition. The reaction temperature data represents the real-time temperature data of the catalyst layer in the denitrification reaction, used to assess whether the reaction is proceeding within an effective temperature range. The standard reaction temperature range refers to the ideal temperature range required for the denitrification catalytic reaction. Based on this, the extracted actual temperature data is compared with the upper and lower limits of the range. If the temperature is below the minimum value, it is marked as a low-temperature anomaly. If the temperature is above the maximum value, it is marked as a high-temperature anomaly. The temperature anomaly is either a low-temperature anomaly or a high-temperature anomaly. A low-temperature anomaly refers to a reaction temperature data below the minimum value of the standard reaction temperature range. Low temperatures lead to insufficient catalyst activity, a reduced nitrogen oxide reduction reaction rate, and a decrease in denitrification efficiency. Incomplete ammonia reaction increases the risk of ammonia slip. A high-temperature anomaly refers to a reaction temperature data above the maximum value of the standard reaction temperature range. High temperatures can lead to catalyst deactivation or accelerated aging, reducing its lifespan, increasing side reactions, and impacting environmental performance. If the temperature anomaly is a low-temperature anomaly, the minimum value of the standard reaction temperature range is subtracted from the reaction temperature data to obtain the low-temperature deviation value; if the temperature anomaly is a high-temperature anomaly, the maximum value of the standard reaction temperature range is subtracted from the reaction temperature data to obtain the high-temperature deviation value. The low-temperature deviation value indicates the degree of the low-temperature anomaly and is used to guide the adjustment of heating equipment. The high-temperature deviation value indicates the degree of the high-temperature anomaly and is used to adjust combustion parameters.

[0094] Step 2: Generate the heating intensity mode of the hot blast stove based on the low temperature deviation value; adjust the coke oven combustion parameters based on the high temperature deviation value.

[0095] In some embodiments, firstly, a heating intensity mode table is pre-established, where the low-temperature deviation range and corresponding heating intensity mode are defined in the table, and the heating intensity mode can be low, medium, or high. Then, the low-temperature deviation value is queried to find the range specified in the table, thereby determining the corresponding heating intensity mode. The heating intensity mode of the hot blast stove is a working mode generated based on the low-temperature deviation value, used to control the heating output intensity of the hot blast stove and ensure that the reaction temperature is raised to the standard range. Combustion parameters such as fuel supply and air ratio are dynamically adjusted based on the high-temperature deviation value. Coke oven combustion parameters are key control variables in the coke oven combustion process, such as fuel supply, air ratio, and combustion temperature setting.

[0096] Step 3: If the temperature anomaly is a low temperature anomaly, then the first sub-category of the fifth category of the candidate inspection items set and the heating intensity mode are included in the inspection list; if the temperature anomaly is a high temperature anomaly, then the second sub-category of the fifth category of the candidate inspection items set and the coke oven combustion parameters are included in the inspection list. The first sub-category of the inspection items represents the inspection and adjustment of the hot blast stove, and the second sub-category of the inspection items represents the inspection and adjustment of the coke oven combustion parameters.

[0097] In some embodiments, if the temperature anomaly is a low-temperature anomaly, the conditions for introducing the first sub-category of inspection items in the fifth category of the candidate inspection item set are met, and the first sub-category of inspection items and the heating intensity mode are added to the inspection list. If the temperature anomaly is a high-temperature anomaly, the conditions for introducing the second sub-category of inspection items in the fifth category of the candidate inspection item set are met, and the second sub-category of inspection items and the coke oven combustion parameters that need to be adjusted are added to the inspection list. The first sub-category of inspection items is related to low-temperature anomalies, checking the equipment status and operating parameters of the hot blast stove, and adjusting the hot blast stove according to the heating intensity mode. The second sub-category of inspection items is related to high-temperature anomalies, checking and adjusting the combustion parameters of the coke oven.

[0098] In these embodiments, the concentration of ammonia slip was precisely controlled, improving the reliability and environmental performance of the denitrification system. Specifically, firstly, the reaction temperature data of each denitrification chamber was extracted from the denitrification operation and compared with the standard reaction temperature range to identify low-temperature or high-temperature anomalies, and the corresponding temperature deviation values ​​were calculated. Then, the heating intensity mode of the hot blast stove was generated based on the low-temperature deviation value, and the combustion parameters of the coke oven were adjusted based on the high-temperature deviation value. Finally, the inspection items and adjustment measures corresponding to the anomaly types were included in the inspection checklist. Low-temperature anomalies corresponded to the inspection and adjustment of the hot blast stove, and high-temperature anomalies corresponded to the inspection and adjustment of the coke oven combustion parameters. This achieved precise control of the catalyst reaction temperature, thereby precisely controlling the ammonia slip concentration and improving the reliability and environmental performance of the denitrification system.

[0099] The above description is merely a selection of preferred embodiments of the present invention and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention is not limited to specific combinations of the above-described technical features, but also includes other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in this invention.

Claims

1. A method for ammonia slip control of an SCR De-NOx system, characterized in that, The method comprises the following steps: acquiring a plurality of denitration working conditions corresponding to each denitration chamber in the plurality of denitration chambers through an ammonia escape online monitoring system; jointly analyzing the denitration working conditions to determine at least one denitration chamber to be checked from the plurality of denitration chambers, comprising: determining the nitrogen oxide over-standard situation at the inlet corresponding to each denitration chamber, the proportion of over-standard denitration chambers in the plurality of denitration chambers, and the average nitrogen oxide concentration at the inlet of flue gas; if the proportion of over-standard denitration chambers is greater than a preset proportion value, continuously adjusting the working load of the current waste gas blower according to the average nitrogen oxide concentration at the inlet of flue gas until the recalculated proportion of over-standard denitration chambers is less than or equal to the preset proportion value; using an ammonia escape mobile monitoring device to detect the ammonia escape concentration of each denitration chamber to be checked to obtain a real-time ammonia escape concentration; if the real-time ammonia escape concentration is greater than a preset ammonia escape concentration threshold, the denitration chamber is determined as a target denitration chamber; for each target denitration chamber, constructing a corresponding check list according to one or more of the following: the injection valve opening degree, the nitrogen oxide concentration at the inlet of flue gas, the nitrogen oxide concentration at the outlet of flue gas, the real-time ammonia escape concentration, and the maintenance record, comprising: if the third type of check item included in the check list is an independent check item, determining whether the ammonia escape control effect meets the standard according to the ammonia escape concentration trend and the nitrogen oxide concentration trend at the outlet of flue gas; if it does not meet the standard, by querying the maintenance record in the historical time period, the check item with a time interval between the latest implementation time and the current time greater than the standard maintenance interval is included in the corresponding check list; for a large-flow denitration chamber, the nitrogen oxide concentration data corresponding to multiple detection ports are extracted to calculate the denitration efficiency difference, if the difference exceeds the threshold, it is determined as the first type of check item and included in the check list; for a medium-flow denitration chamber or a small-flow denitration chamber, the actual ratio of the injection valve opening degree to the nitrogen oxide concentration at the inlet of flue gas is calculated and compared with the preset ratio, if the actual ratio is too high, it is determined as the third type of check item and included in the check list; screening the associated check item whose introduction condition is hit from at least one associated check item as a target associated check item according to the ammonia escape concentration trend, the nitrogen oxide concentration trend at the outlet of flue gas, and the introduction condition of each associated check item; including the target associated check item in the corresponding check list; after a preset time period, retesting the ammonia escape concentration of each target denitration chamber after adjustment, and generating an ammonia escape control effect report according to the retested ammonia escape concentration.

2. The SCR de-NOx system ammonia slip control method according to claim 1, characterized by, The jointly analyzing the denitration working conditions corresponding to the plurality of denitration chambers to determine at least one denitration chamber to be checked from the plurality of denitration chambers comprises: extracting the nitrogen oxide concentration at the inlet of flue gas from the denitration working conditions to obtain the nitrogen oxide concentration at the inlet of flue gas corresponding to each denitration chamber; determining the standard nitrogen oxide concentration at the inlet of flue gas according to the current coke oven production load condition, which is full production or reduced production; Based on the corresponding nitrogen oxide concentration at the flue gas inlet and the standard nitrogen oxide concentration at the flue gas inlet, the nitrogen oxide exceedance at the inlet of each denitrification chamber, the proportion of denitrification chambers exceeding the standard, and the average nitrogen oxide concentration at the flue gas inlet are determined. If the proportion of denitrification chambers exceeding the standard is greater than the preset proportion value, the current working load of the exhaust gas return fan is continuously adjusted based on the average nitrogen oxide concentration at the flue gas inlet until the recalculated proportion of denitrification chambers exceeding the standard is less than or equal to the preset proportion value. The actual ammonia escape concentration is extracted from the denitrification operation, and the denitrification chambers with actual ammonia escape concentration greater than the preset escape concentration are identified as denitrification chambers to be investigated, thus obtaining at least one denitrification chamber to be investigated.

3. The SCR de-NOx system ammonia slip control method according to claim 2, characterized by, For each target denitrification chamber in the target denitrification chamber group, a corresponding inspection checklist is constructed based on one or more of the following: the opening degree of the spray valve, the nitrogen oxide concentration at the flue gas inlet, the nitrogen oxide concentration at the flue gas outlet, the real-time ammonia escape concentration, and maintenance records. This checklist includes: For each target denitrification chamber, determine the opening degree of the spray valve on the ammonia injection grid branch pipe. If the spray valve opening degree is greater than the first set opening degree, the corresponding target denitrification chamber is determined as a high-flow ammonia denitrification chamber. If the spray valve opening degree is less than the second set opening degree, the corresponding target denitrification chamber is determined as a low-flow ammonia denitrification chamber. If the spray valve opening degree is greater than the second set opening degree and less than the first set opening degree, the corresponding target denitrification chamber is determined as a medium-flow ammonia denitrification chamber. For a high-flow-rate ammonia denitrification chamber, the first nitrogen oxide concentration data corresponding to the first detection port and the second nitrogen oxide concentration data corresponding to the second detection port are extracted from the denitrification operating conditions. The first nitrogen oxide concentration data includes the nitrogen oxide concentration at the first flue gas inlet and the first flue gas outlet, and the second nitrogen oxide concentration data includes the nitrogen oxide concentration at the second flue gas inlet and the second flue gas outlet. Based on the nitrogen oxide concentrations at the first flue gas inlet and the first flue gas outlet, the first denitrification efficiency corresponding to the first detection port is calculated. Based on the nitrogen oxide concentrations at the second flue gas inlet and the second flue gas outlet, the second denitrification efficiency corresponding to the second detection port is calculated. If the difference between the first denitrification efficiency and the second denitrification efficiency is greater than a preset difference threshold, then the first type of inspection items in the candidate inspection item set is included in the corresponding inspection list. The first type of inspection items represents the inspection and adjustment of the denitrification uniformity of the denitrification chamber.

4. The SCR de-NOx system ammonia slip control method according to claim 3, characterized by, For each target denitrification chamber in the target denitrification chamber group, a corresponding inspection checklist is constructed based on one or more of the following: the opening degree of the spray valve, the nitrogen oxide concentration at the flue gas inlet, the nitrogen oxide concentration at the flue gas outlet, the real-time ammonia escape concentration, and maintenance records. This checklist also includes: For a large-flow ammonia denitration chamber, if a difference between the first denitration efficiency and the second denitration efficiency is less than or equal to a preset difference threshold, an average denitration efficiency is determined according to the first denitration efficiency and the second denitration efficiency, and the average denitration efficiency is compared with a benchmark denitration efficiency, if the average denitration efficiency is less than the benchmark denitration efficiency, a second type of inspection item in the candidate inspection item set is listed in the corresponding inspection list, wherein the second type of inspection item represents inspection and adjustment of a flue gas outlet valve or a flue gas inlet valve of the denitration chamber.

5. The SCR de-NOx system ammonia slip control method according to claim 4, characterized by, For each target denitration chamber in the target denitration chamber group, a corresponding inspection list is constructed according to one or more of the following: the injection valve opening degree, the nitrogen oxide concentration at the flue gas inlet, the nitrogen oxide concentration at the flue gas outlet, the real-time ammonia escape concentration, and the maintenance record, and further comprising: For a medium-flow ammonia denitration chamber or a small-flow ammonia denitration chamber, an actual ratio of the injection valve opening degree and the nitrogen oxide concentration at the flue gas inlet is calculated, if the actual ratio is greater than a preset ratio, a third type of inspection item in the candidate inspection item set is listed in the corresponding inspection list, wherein the third type of inspection item represents inspection and adjustment of the injection valve opening degree on the ammonia injection grid branch pipe to reduce the ammonia flow; the ammonia escape concentration and the nitrogen oxide concentration at the flue gas outlet after the ammonia flow is reduced are tracked to obtain the ammonia escape concentration change trend and the nitrogen oxide concentration change trend at the flue gas outlet; According to the independence identifier, it is determined whether each third type of inspection item listed in the inspection list is an independent inspection item; if it is not an independent inspection item, at least one associated inspection item of the third type of inspection item listed in the inspection list and the introduction condition of each associated inspection item are queried. 6.The SCR De-NOx system ammonia slip control method of claim 5, wherein, For each target denitration chamber in the target denitration chamber group, a corresponding inspection list is constructed according to one or more of the following: the injection valve opening degree, the nitrogen oxide concentration at the flue gas inlet, the nitrogen oxide concentration at the flue gas outlet, the real-time ammonia escape concentration, and the maintenance record, and further comprising: If the third type of inspection item listed in the inspection list is an independent inspection item, it is determined whether the ammonia escape control effect meets the standard according to the ammonia escape concentration change trend and the nitrogen oxide concentration change trend at the flue gas outlet; if the ammonia escape control effect does not meet the standard, the maintenance record in the historical time period is queried to determine the latest implementation time of each inspection item and the standard maintenance interval length, and the inspection item whose time interval between the latest implementation time and the current time is greater than the standard maintenance interval length is listed in the corresponding inspection list.

7. The SCR deNOx system ammonia slip control method according to claim 6, wherein Further comprising: For each target denitration chamber in the target denitration chamber group, the dust concentration at the flue gas inlet and the dust concentration at the flue gas outlet are obtained from the denitration working condition; The difference between the dust concentration at the flue gas inlet and the dust concentration at the flue gas outlet is calculated, and the difference is compared with a preset difference; If the difference is greater than or equal to the preset difference, a fourth type of inspection item in the candidate inspection item set is listed in the corresponding inspection list, wherein the fourth type of inspection item represents inspection and adjustment of the damage of the dust removal bag.

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