Boiler tail gas treatment method

Abstract

The invention relates to the field of tail gas treatment, and discloses a boiler tail gas treatment method which is used for achieving cooperative control over the spraying amount of a desulfurizing agent, the activity degree of a catalyst and the reaction temperature. Comprising the following steps of: establishing a multi-zone reaction system at a tail flue of a boiler; acquiring real-time operation data by utilizing multiple detection devices and integrating the data to form a database; calculating a desulfurizing agent demand; analyzing catalyst compensation; the catalyst adding proportion and the opening degree of an air door of a flue gas recirculation system are adjusted, the power of a heat exchanger is synchronously adjusted, the pollutant concentration is detected in real time through an online monitoring device, and the spraying amount of a desulfurizing agent and the catalyst supplementing rate are dynamically adjusted.

Description

Technical Field

[0001] This invention relates to the field of exhaust gas treatment, and more particularly to a method for treating boiler exhaust gas. Background Technology

[0002] In the power industry, it is well known that boilers are large pieces of equipment in thermal power plants that supply steam to steam turbines, primarily for power generation. However, the exhaust gas generated during boiler operation contains a large amount of pollutants, such as sulfur dioxide, nitrogen oxides, and dust. If these pollutants are emitted directly without effective treatment, they will severely pollute the atmospheric environment, exacerbate environmental problems such as acid rain and photochemical smog, and pose a threat to human health and ecosystems. Therefore, developing efficient and reliable boiler exhaust gas treatment technologies to achieve pollutant reduction and resource utilization has become an urgent task in the field of environmental protection.

[0003] Traditional boiler flue gas treatment technologies, such as wet desulfurization, dry desulfurization, and selective catalytic reduction (SCR) denitrification, while reducing pollutant emissions to some extent, still have many limitations. Wet desulfurization technology, although highly efficient, suffers from equipment corrosion, complex wastewater treatment, and difficulties in utilizing byproducts. Dry desulfurization technology, while simple in equipment and easy to operate, has desulfurization efficiency limited by reaction conditions, and byproduct treatment also faces challenges. SCR denitrification technology, although effectively reducing NOx... x While emissions are controlled, catalysts are susceptible to poisoning and deactivation, requiring regular replacement and increasing operating costs. Furthermore, existing technologies typically employ independent treatment units for single pollutants, with each unit operating relatively independently. Although these methods can meet basic emission requirements, there is still room for improvement in the synergistic treatment of multiple pollutants and in optimizing overall system energy efficiency to cope with significant fluctuations in operating conditions.

[0004] Therefore, we propose a boiler exhaust gas treatment method to solve the above problems. Summary of the Invention

[0005] This invention provides a boiler exhaust gas treatment method for achieving coordinated control of desulfurizing agent injection quantity, catalyst activity, and reaction temperature.

[0006] The first aspect of this invention provides a boiler exhaust gas treatment method, comprising: establishing a multi-zone reaction system in the boiler tail flue; acquiring real-time operating data during the exhaust gas treatment process using temperature sensors, concentration detectors, and differential pressure gauges arranged at different locations in the flue; establishing a control model based on the real-time operating data, including three parameters: desulfurizing agent injection quantity, catalyst activity, and reaction temperature, and generating optimized control parameters; adjusting the desulfurizing agent injection device, catalyst replenishment system, and temperature regulation device respectively through a PLC controller according to the optimized control parameters to form coordinated control commands; and controlling the injection position and injection quantity of desulfurizing agent in the flue according to the coordinated control commands, while adjusting the distribution density of catalyst in the reactor and controlling the heat exchange rate of the heat exchanger.

[0007] Optionally, in a first implementation of the first aspect of the present invention, the method includes: installing a first set of temperature sensors and an SO2 concentration detector at the front end of the precooling zone to obtain initial temperature distribution data and initial pollutant concentration data at the inlet of the precooling zone; and setting a second set of temperature sensors and a differential pressure gauge in the middle of the main reaction zone to obtain temperature change data and pressure loss data during the reaction process. A third set of concentration detectors is arranged at the end of the main reaction zone to obtain intermediate pollutant concentration data after the reaction; a fourth set of temperature sensors and concentration detectors is set at the outlet of the post-treatment zone to obtain final emission temperature data and final pollutant concentration data; the initial temperature distribution data, initial pollutant concentration data, temperature change data, pressure loss data, intermediate pollutant concentration data, final emission temperature data and final pollutant concentration data are integrated and processed to form a real-time operating database.

[0008] Optionally, in a second implementation of the first aspect of the present invention, desulfurizer demand parameters are calculated based on the initial pollutant concentration data and intermediate pollutant concentration data; a catalyst activity evaluation model is constructed, and catalyst compensation parameters are analyzed based on the temperature change data and pressure loss data; temperature regulation parameters are generated based on the initial temperature distribution data and final emission temperature data; a system coordinated control scheme is formed by coupling analysis of the desulfurizer demand parameters, catalyst compensation parameters, and temperature regulation parameters; and an optimized control parameter set is generated based on the system coordinated control scheme, including the precise dosage of desulfurizer, catalyst replenishment rate, and temperature setpoint.

[0009] Optionally, in the third implementation of the first aspect of the present invention, a reaction efficiency model of the desulfurizing agent in different temperature ranges is established to generate a staged reaction scheme; a catalyst activity decay compensation model is established based on the flue gas composition variation characteristics to generate a catalyst activity maintenance strategy; a temperature field distribution optimization model is established in conjunction with the flue gas flow characteristics to generate a temperature gradient control scheme; a desulfurizing agent precise dosing strategy is formed by coupling analysis of the staged reaction scheme and the temperature gradient control scheme; and the catalyst activity maintenance strategy and the desulfurizing agent precise dosing strategy are synergistically integrated to form a system operation optimization scheme.

[0010] Optionally, in the fourth implementation of the first aspect of the present invention, the method includes: converting the precise dosage of the desulfurizing agent into a control signal for the desulfurizing agent injection device to generate a multi-stage injection command; converting the catalyst replenishment rate into a drive signal for the catalyst replenishment system to generate a catalyst replenishment command; converting the temperature setpoint into an adjustment signal for the temperature regulating device to generate a temperature control command; and integrating the multi-stage injection command, the catalyst replenishment command, and the temperature control command in a time sequence to form a coordinated control command set.

[0011] Optionally, in the fifth implementation of the first aspect of the present invention, based on the flow velocity of flue gas in the flue, the time interval for desulfurizing agent injection between the precooling zone and the main reaction zone is set to generate a desulfurizing agent injection timing scheme; based on the pressure drop change trend of the catalyst bed, the start-up and shutdown time sequence of the screw conveyor is set to generate a catalyst replenishment timing scheme; based on the flue gas temperature change rate, the linkage control timing sequence between the flue gas recirculation system and the heat exchanger is set to generate a temperature regulation timing scheme; the desulfurizing agent injection timing scheme, the catalyst replenishment timing scheme, and the temperature regulation timing scheme are processed to form a system-level timing coordination control framework; based on the timing coordination control framework, a coordination control instruction set is generated, and the instruction set is converted into an action timing table for each actuator.

[0012] Optionally, in the sixth implementation of the first aspect of the present invention, the method includes: performing a coarse injection operation in the precooling zone, forming an alkaline atomization zone in the precooling zone according to the injection amount in the precooling zone of the multi-stage injection command, and generating preliminary desulfurization products; performing a fine injection operation in the main reaction zone, forming a directional injection flow field in the main reaction zone according to the injection amount in the main reaction zone of the multi-stage injection command, and generating deep desulfurization products; adjusting the addition ratio of catalyst in different reaction zones according to the catalyst replenishment command via a spiral conveyor device to form a catalyst bed and generate an optimized reaction environment; controlling the damper opening of the flue gas recirculation system according to the temperature control command to generate a stable flue gas mixing flow field; and synchronously adjusting the working power of the heat exchanger to generate a precisely controlled reaction temperature field based on the heat exchanger power parameters in the temperature control command.

[0013] Optionally, in the seventh implementation of the first aspect of the present invention, it further includes using an online monitoring device installed at the flue outlet to detect the concentration of pollutants in the exhaust gas in real time, obtain the detection results, and dynamically adjust the desulfurizing agent injection rate and catalyst replenishment rate accordingly; acquiring SO2 concentration monitoring data in real time and generating an SO2 concentration change trend graph; acquiring NO... x Concentration monitoring data, generating NO x Concentration distribution curve; real-time acquisition of dust concentration monitoring data, generation of dust concentration monitoring reports; and display of the SO2 concentration change trend chart and NO... x The concentration distribution curve and dust concentration monitoring report are comprehensively analyzed to generate an emission quality assessment report. Based on the emission quality assessment report and the preset emission standard limits, a system operation status diagnosis result is generated. According to the system operation status diagnosis result, a desulfurizing agent injection quantity correction command and a catalyst replenishment rate adjustment command are generated. The desulfurizing agent injection quantity correction command and catalyst replenishment rate adjustment command are sent to the PLC controller to realize real-time dynamic adjustment of the desulfurizing agent injection device and the catalyst replenishment system.

[0014] Optionally, in the eighth implementation of the first aspect of the present invention, the correction amount in the desulfurizing agent injection quantity correction command is: : in, For correction amount, This is the proportionality coefficient. The integral coefficient is... and These are the actual concentration and the target concentration, respectively.

[0015] Optionally, in the ninth implementation of the first aspect of the present invention, the method further includes: collecting reaction byproducts generated during the desulfurization process to generate mixed ash; conveying the mixed ash to a hydraulic separation device, and obtaining a solid filter cake and a clarified filtrate through multi-stage sedimentation and filtration; conveying the solid filter cake to a solidification and molding device, adding a curing agent and a stabilizer to prepare an environmentally friendly building material raw material; introducing the clarified filtrate into a neutralization reaction tank, adjusting the pH value to a neutral range to obtain compliant recycled water; and conveying the compliant recycled water to the spray system of the pre-cooling zone for recycling as cooling spray water.

[0016] The mechanism of this invention is as follows: a boiler exhaust gas treatment system based on multi-zone collaboration, time-sequence control, and resource recycling is constructed; Beneficial effects: By establishing a multi-zone reaction system in the boiler tail flue, including a pre-cooling zone, a main reaction zone, and a post-treatment zone, and by arranging temperature sensors, concentration detectors, and differential pressure gauges in different zones, refined zoned monitoring of the tail gas treatment process is achieved. Based on real-time operating data, a desulfurizer demand model, a catalyst activity evaluation model, and a temperature regulation model were constructed. Through coupled analysis, a system coordinated control scheme was generated. The system can generate an optimized set of control parameters in real time according to the dynamic changes in exhaust gas composition and operating conditions, so that the system always operates in the best state and enhances its adaptability to different boiler types and operating conditions. The timing of operations such as desulfurizing agent injection, catalyst replenishment and temperature regulation was ensured, avoiding the decrease in processing efficiency or equipment damage caused by improper operation timing. At the same time, the processing flow was further optimized and the reaction efficiency was improved through the staged reaction scheme and temperature gradient control scheme. The reaction byproducts generated during the desulfurization process are collected, separated, and solidified to prepare environmentally friendly building material raw materials. The clarified filtrate is then adjusted to pH value and recycled, realizing the resource utilization of byproducts, reducing waste emissions, lowering the negative impact on the environment, and saving water resources and raw material costs, thus achieving good economic and environmental benefits. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of one embodiment of the boiler exhaust gas treatment method of the present invention; Figure 2 This is a schematic diagram of another embodiment of the boiler exhaust gas treatment method in this invention; Figure 3 A layout diagram of the monitoring equipment for the multi-zone reaction system in the boiler tail flue; Figure 4 This is a schematic diagram of one embodiment of the boiler exhaust gas treatment equipment in this invention. Detailed Implementation

[0018] This invention provides a boiler exhaust gas treatment method for achieving coordinated control of desulfurizer injection quantity, catalyst activity, and reaction temperature. The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms "comprising" or "having" and any variations thereof are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0019] For ease of understanding, the specific process of the embodiments of the present invention is described below. Please refer to [link / reference]. Figure 1One embodiment of the boiler exhaust gas treatment method of the present invention includes: 101. Establish a multi-zone reaction system in the boiler tail flue, and obtain real-time operating data of the tail gas treatment process by arranging temperature sensors, concentration detectors and differential pressure gauges at different locations in the flue. It is understood that the executing entity of this invention can be a boiler exhaust gas treatment device, a terminal, or a server; no specific limitation is made here. This embodiment of the invention will be described using a server as an example.

[0020] It should be noted that, taking a typical SCR (Selective Catalytic Reduction) denitrification system for a coal-fired boiler as an example, the tail flue is divided into three zones: the inlet zone (after the economizer), the reaction zone (inside the SCR denitrification unit), and the outlet zone (before the air preheater). Temperature sensors and NO concentration detectors are installed in each zone. x The system includes an O2 analyzer and a differential pressure gauge to collect real-time operating data.

[0021] Zoning Design: The flue is physically divided into three series-connected functional zones, corresponding to the exhaust gas treatment process: Inlet Zone: Responsible for initial monitoring and pretreatment of exhaust gas, with a flue cross-section of 3m × 4m. Reaction Zone: The core denitrification area, with an internal SCR catalyst layer (honeycomb catalyst), and a flue length of 8m. Outlet Zone: Used to verify treatment effectiveness, with the same flue cross-section as the inlet zone. Zoning Purpose: To achieve gradient control through zoning; the inlet zone monitors the initial exhaust gas state, the reaction zone optimizes the reduction reaction, and the outlet zone assesses the final emission indicators.

[0022] Sensors are installed at key locations in each zone to ensure coverage of representative points (center and edges) of the flue cross-section. All sensor signals are transmitted to the central data acquisition system via 4-20mA or HART protocol, with a sampling frequency of 1 time / second. The specific layout is shown in Table 1 below: Table 1 Installation Details: Sensors must be kept away from eddy current zones; temperature sensors should be fitted with protective sleeves to prevent corrosion; concentration detectors extract flue gas through sampling branch pipes (reducing pipe design, 38-40mm diameter) and are heated with 100mm thick insulation to prevent condensation. Data Synchronization: All zone data are timestamped using a unified timescale to ensure data synchronization (deviation <1 second) between the inlet, reaction, and outlet zones, avoiding control lag due to measurement delays. Example Data: Under rated load, typical real-time data includes: inlet zone temperature 320℃, NO... x Concentration 450 ppm; pressure difference in reaction zone 0.8 kPa; NO in outlet zone x Concentration <50ppm. These data are directly used for subsequent modeling and optimization.

[0023] 102. Based on real-time operating data, establish a control model that includes three parameters: desulfurizing agent injection rate, catalyst activity, and reaction temperature, and generate optimized control parameters; It should be noted that by integrating data collected from multiple reaction systems (exhaust gas temperature, NO...) x (Concentration, pressure difference, etc.) to construct a control model with the injection amount of desulfurizing agent (ammonia), catalyst activity and reaction temperature as the core, and finally output optimized parameters to guide subsequent control.

[0024] Real-time data is obtained from the multi-zone reaction system in step 101, including: Temperature data: flue gas temperature at the reactor inlet, catalyst bed, and outlet (inlet temperature 320℃±10℃). Concentration data: inlet NO... x Concentration (450±50mg / m 3 ), Export NO x Concentration (target ≤50mg / m³) 3 Ammonia slip concentration (limited to <3ppm). Pressure differential data: catalyst bed pressure differential (normal range 0.5-1.0kPa, reflecting blockage status). Other parameters: flue gas flow rate (100,000m³ / h). 3 / h), oxygen content (3-5%), unit load (500MW).

[0025] These data are collected every 10 seconds by the DCS system and undergo preprocessing (outlier removal and normalization) to ensure quality. If the input NO... x The concentration sensor's hysteresis causes data distortion. An RBF neural network is used to predict and correct values, reducing the impact of a 5-10 minute measurement delay.

[0026] A hybrid approach combining data-driven and mechanistic modeling is employed to map parameters to a denitrification efficiency target (≥90%). The model structure is as follows: Desulfurizing agent injection quantum model: based on inlet NO... x The concentration and flue gas flow rate are used to calculate the theoretical ammonia injection rate through nonlinear regression, and the rate is dynamically adjusted based on ammonia slip feedback. The basic formula for the ammonia injection rate is: The coefficient k is determined by fitting historical data.

[0027] The catalyst activity sub-model, with the specific formula as follows: in, The current activity coefficient (0-1); Use 1.0 as the initial activity baseline. The differential pressure value is monitored in real time. The reference pressure difference is 300 Pa. The maximum permissible pressure difference (1000 Pa); Cumulative running time; Design life; , These are weighting coefficients (taken as 0.4 and 0.6 respectively). When the calculated... When the value is less than 0.6, the system determines that the activity is insufficient and triggers an early warning. The model optimizes parameters using an intelligent algorithm: It employs particle swarm optimization to minimize the objective function (denitrification efficiency variance + ammonia slip penalty term) and generate the optimal parameter combination. Table 2 below shows the model input and output of a 500MW unit under typical load: Table 2 Training process: Using 3 months of historical data (approximately 100,000 records), a model was trained using a neural network (EEMD-IWOA-DELM algorithm) to predict export NO. x Concentration error is controlled within ±5%. Dynamic verification: The model is verified every 4 hours using real-time data. If the deviation between the predicted value and the measured value exceeds 8%, the model parameters are automatically updated (adjusting the weight of the ammonia injection amount).

[0028] The model output includes: direct control parameters: ammonia injection rate setpoint, temperature adjustment setpoint, and catalyst replenishment cycle (1% active material replenishment every 100 hours). Constraint parameters: ammonia slip limit (<3ppm) and differential pressure safety threshold (≤1.2kPa), ensuring the system operates within environmental and safety limits.

[0029] When the entrance is NO x The concentration suddenly increased to 500 mg / m³ 3 At that time, the model calculations showed that the ammonia injection rate needed to be increased from 35 kg / h to 42 kg / h, while simultaneously adjusting the heat exchanger to stabilize the temperature at 340℃, thereby ensuring the output NO... x The concentration meets the standard.

[0030] 103. Input the optimized control parameters into the central control system, and adjust the desulfurizing agent injection device, catalyst replenishment system and temperature control equipment through the PLC controller to form coordinated control commands; It should be noted that the optimized control parameters (generated from the model in step 102) are converted into executable coordinated control commands, which are then used to regulate the desulfurizing agent (ammonia) injection device, catalyst replenishment system, and temperature control equipment through the coordinated operation of the central control system (DCS) and PLC controller. An implementation example is as follows: Parameter source: The optimized parameters generated in step 102 include the ammonia injection rate setpoint (38 kg / h), catalyst activity compensation coefficient (0.82), and reaction temperature setpoint (345℃). These parameters are transmitted from the server to the central control system (DCS) via Ethernet communication (OPCUA protocol).

[0031] Parameter Analysis: The DCS categorizes parameters by equipment type: Desulfurizing Agent Injection Device: Receives the total ammonia injection setpoint and the ammonia injection valve opening degree for each zone (Zone A 45%, Zone B 50%). Catalyst Replenishment System: Receives the activity compensation coefficient (0.82) and converts it into the replenishment frequency (replenishment once every 120 hours). Temperature Control Equipment: Receives the reaction temperature setpoint (345℃) and converts it into the heat exchanger steam valve opening degree or economizer bypass damper position. Safety Verification: The DCS performs boundary checks on the parameters (ammonia injection limit 20-60 kg / h, temperature limit 300-400℃). If limits are exceeded, an alarm is triggered and the command output is locked.

[0032] As the execution unit, the PLC receives instructions from the DCS and generates specific equipment instructions through pre-programmed logic algorithms (PID control, sequential control). Table 3 below shows the coordinated control logic of a 1050MW unit at a load of 750MW: Table 3 Command synchronization: The PLC ensures that the timestamp deviation of the commands for the three types of equipment is less than 1 second to avoid control lag. The adjustment of the ammonia injection valve and the temperature regulation must be executed synchronously to prevent ammonia escape due to temperature fluctuations.

[0033] Safety interlock: If the ammonia escape concentration > 3 ppm, the PLC will forcibly close the ammonia injection valve for 10 seconds. If the reaction temperature < 300℃, ammonia injection will be paused and the heat exchanger will be activated at maximum power. If the catalyst pressure difference > 1.5 kPa, an alarm will be triggered and the ammonia injection rate will be reduced by 20%.

[0034] Command output: The PLC converts the final command into a 4-20mA analog signal or bus signal (Profibus) and sends it to the field equipment. The ammonia injection valve opening signal (50%) corresponds to a 12mA output, and the catalyst feeder frequency is set to 35Hz.

[0035] 104. According to the coordinated control instructions, control the injection position and injection amount of desulfurizing agent in the flue, while adjusting the distribution density of catalyst in the reactor and controlling the heat exchange rate of the heat exchanger. It should be noted that, based on the coordinated control commands generated by the PLC, the injection position and flow rate of the desulfurizing agent (ammonia), the distribution density of catalyst activity, and the heat exchange rate of the heat exchanger are adjusted synchronously to ensure denitrification efficiency and reduce the risk of ammonia escape. Zoned ammonia injection regulation: The coordinated control command includes the opening setpoint values ​​for each zone of the ammonia injection grid (AIG). A certain 1050MW unit divides the SCR reactor outlet flue into 16 zones (8 zones each on the A / B side), with each zone corresponding to a pneumatic regulating valve. The command is based on real-time NO... xDistributed (measured via grid method) adjustment of valve opening: If the outlet zone NO x High concentration (>50mg / m³) 3 If ammonia escape exceeds the limit (>3 ppm), increase the valve opening of the corresponding zone by 5-10% (from 40% to 45%); if ammonia escape exceeds the limit in a local area (>3 ppm), reduce the valve opening of that zone by 3-5% to avoid over-spraying. The total ammonia injection is determined by the PLC based on the inlet NO. x Concentration (450mg / m³) 3 ) and flue gas flow rate (100,000 m³) 3 The calculation is performed using the main regulating valve (213 kg / h for full load and 113 kg / h for medium load).

[0036] Dynamic correction mechanism: Employing fuzzy feedforward control, when the unit load changes abruptly (increasing or decreasing by 50MW per minute), it anticipates and corrects the load based on NO... x Adjusting the ammonia injection rate based on changing trends: When the load increases, the instruction will increase the ammonia injection rate by 15% proportionally within 30 seconds to ensure uniform mixing of ammonia and flue gas (outlet NO). x The relative standard deviation of the distribution decreased from 36% before the modification to below 8%.

[0037] Soot blowing and replenishment synergistic: The spatial distribution of catalyst activity is regulated by the ratio of zoned addition. Specifically, the reactor is divided into three feeding zones—front, middle, and rear—along the flue gas flow direction. The system determines blockage or deactivation based on the readings of the differential pressure sensors in each zone. If the front-end differential pressure increases too rapidly, the speed of the front-end screw conveyor is reduced, while the speeds of the middle and rear conveyors are increased proportionally to alter the mass distribution density of fresh catalyst in the bed, thereby indirectly regulating activity. Command control of soot blower frequency (10 minutes of pulse purging every 8 hours) and catalyst replenishment system: When the reactor differential pressure > 1.2 kPa (indicating severe ash accumulation), the soot blowing frequency is increased to once every 4 hours; if the catalyst activity coefficient is below 0.7 (calculated based on the operating time and differential pressure model), a quantitative replenishment procedure is triggered, injecting activator into the reactor (5 kg of active ingredient every 100 hours) to maintain catalytic efficiency. This process is linked to ammonia injection: If ammonia escape continues to > 3 ppm, replenishment is suspended to prevent ammonium bisulfate blockage.

[0038] Precise temperature maintenance: The heat exchanger (economizer bypass or steam heat exchange system) adjusts heat exchange according to the reaction temperature setpoint (340℃). Instructions are used via a PID algorithm to adjust the heat exchange medium flow rate: if the reaction temperature is below 330℃, increase the economizer bypass damper opening to 60% or increase the steam valve opening by 15%; if the temperature is above 380℃, reduce heat source input to prevent catalyst sintering. Temperature fluctuations are controlled within ±5℃ to ensure the catalyst is within its high-efficiency window (300-400℃).

[0039] The control commands for the three types of equipment are executed synchronously by the PLC with a time deviation of less than 1 second, and conflicts are avoided through interlocking logic. Table 4 below illustrates the coordinated control parameters under typical loads: Table 4 105. The concentration of pollutants in the exhaust gas is detected in real time by an online monitoring device installed at the flue outlet, and the detection results are fed back to the central control system to dynamically adjust the desulfurizing agent injection volume and catalyst replenishment rate. It should be noted that the online monitoring device at the flue outlet detects the concentration of pollutants in the exhaust gas in real time and feeds the data back to the central control system, dynamically adjusting the injection volume of desulfurizing agent (ammonia) and the catalyst replenishment rate to form a closed-loop control system. A multi-parameter online monitoring system (CEMS) was installed in the outlet flue of the SCR reactor, including: Monitoring point layout: 12 monitoring points (using a grid method) were arranged on the cross-section of the outlet flue, covering the center, edges, and other areas to avoid measurement bias. A direct-insertion in-situ analyzer was installed at each monitoring point, collecting a set of data every 30 seconds.

[0040] Monitoring parameters and instrument selection: NO x Concentration: Ultraviolet differential absorption spectroscopy (UV-DOAS) was used, with a range of 0-1000ppm and an accuracy of ±1%FS, to calculate the denitrification efficiency (target: outlet NO). x ≤50mg / m 3 Ammonia slip concentration: Utilizes TDLAS (Tunable Diode Laser Absorption Spectroscopy) technology, range 0-10ppm, accuracy ±0.5ppm, target control 2-3ppm to prevent corrosion. O2 concentration: Employs a zirconia sensor, range 0-25%, accuracy ±0.1%, used to verify flue gas dilution effects. Auxiliary parameters: Temperature (platinum resistance sensor, range 0-500℃), pressure (piezoresistive transmitter, range 0-5kPa), flow rate (Pitot tube method, range 0-40m / s), used for data compensation.

[0041] Data synchronization and transmission: All sensors upload data to the central control system (DCS) via 4-20mA analog signal or Modbus RTU protocol, with a sampling frequency of 1 time / second and a data delay of less than 5 seconds.

[0042] The central control system (DCS) dynamically adjusts the desulfurizer injection volume via PLC based on the deviation between monitoring data and set thresholds: This adjustment is based on NO... x Concentration feedback: If the outlet NO x The average value was 50 mg / m³. 3 Increased to 60mg / m 3(Exceeding limits), the PLC increases the ammonia injection rate according to the PID algorithm, raising the ammonia injection valve opening from 45% to 52% and the ammonia injection rate from 35 kg / h to 38 kg / h. Based on ammonia slip constraints: if the ammonia slip concentration exceeds 3 ppm, immediately reduce the ammonia injection rate by 5-10% and trigger AIG zone regulation (reducing the valve opening in the high slip zone by 3%). Load linkage: when the unit load drops from 750MW to 500MW, based on the flue gas flow rate (from 100,000 m³ / h...). 3 / h decreased to 70,000m 3 / h) Reduce the ammonia injection rate proportionally to the baseline value. Catalyst replenishment rate adjustment: Based on efficiency and pressure difference: If the denitrification efficiency remains below 85% and the catalyst bed pressure difference is >1.2kPa (activity decreases), start the catalyst replenishment system and inject activator at a rate of 5kg / hour for 2 hours. Periodic replenishment: Replenish every 120 hours based on cumulative operating time (approximately 1% of the total). If ammonia slip remains high, replenish earlier.

[0043] Interlock protection: When ammonia escape > 5 ppm or temperature < 300℃, the ammonia injection valve is forcibly closed for 10 seconds; when the pressure difference > 1.5 kPa, catalyst replenishment is suspended and the soot blowing system is activated. Control target: Through dynamic feedback, the outlet NO... x The concentration remained stable at 50 mg / m³ 3 Within a certain range, ammonia slip is controlled at 2-3 ppm, denitrification efficiency is ≥90%, and ammonia consumption is reduced by 5-10%.

[0044] Table 5 below illustrates the monitoring data and control actions of a 750MW unit under typical load: Table 5 Through real-time feedback, the system optimizes parameters every 2-5 minutes: In one case, the export NO... x Distribution uniformity (CV value) improved from 30.5% to 15%, ammonia consumption decreased by 5%, and catalyst life was extended by approximately 5%. The data was also uploaded to the environmental protection platform to ensure compliant emissions.

[0045] In this embodiment of the invention, the tail flue is divided into three functional zones: an inlet zone, a reaction zone, and an outlet zone. Sensors are strategically placed in each zone to achieve gradient control for monitoring the initial state of the exhaust gas, optimizing the core denitrification reaction, and evaluating the final emission indicators. This allows for a more precise understanding of the characteristics of the exhaust gas at different stages, providing detailed and accurate data support for subsequent optimization control. Compared to traditional single-zone monitoring, this significantly improves the control over the exhaust gas treatment process. By integrating various data collected from the multi-zone reaction system, a control model is constructed with desulfurizing agent injection rate, catalyst activity, and reaction temperature as its core. A hybrid approach combining data-driven and mechanistic models is used to map parameters to denitrification efficiency targets, more accurately reflecting actual operating conditions. Compared to single-parameter or single-modeling methods, this improves the accuracy and reliability of the model. Intelligent algorithms, such as particle swarm optimization, are employed to minimize the objective function and generate the optimal parameter combination. These intelligent algorithms automatically search for the optimal solution, avoiding the blindness and limitations of manual parameter adjustments, thus improving the efficiency and accuracy of parameter optimization. This better guides the operation of the exhaust gas treatment equipment, achieving efficient denitrification. The optimized control parameters are transformed into executable coordinated control commands, which are then linked and adjusted through a central control system (DCS) and PLC controller to regulate the desulfurizing agent injection device, catalyst replenishment system, and temperature control equipment. This allows for rapid and accurate adjustment of equipment operating status based on real-time data and optimized parameters, improving the response speed and control accuracy of the entire exhaust gas treatment system. The DCS performs boundary checks on parameters, triggering alarms and locking command outputs when limits are exceeded. The PLC is equipped with a safety interlock mechanism, taking corresponding protective measures when parameters such as ammonia escape concentration, reaction temperature, and catalyst differential pressure are abnormal. Safety verification and interlock protection functions ensure the safety and stability of the system during operation, preventing equipment damage or excessive exhaust emissions due to abnormal parameters, thus guaranteeing the reliable operation of the boiler exhaust gas treatment system. Online monitoring devices installed at the flue outlet monitor the pollutant concentration in the exhaust gas in real time and feed the results back to the central control system, dynamically adjusting the desulfurizing agent injection rate and catalyst replenishment rate to form a closed-loop control system. This ensures that the exhaust gas treatment effect always meets environmental protection requirements, offering greater adaptability and stability compared to open-loop control systems.

[0046] Please see Figures 2-3 Another embodiment of the boiler exhaust gas treatment method in this invention includes: 201. Establish a multi-zone reaction system in the boiler tail flue, and obtain real-time operating data of the tail gas treatment process by arranging temperature sensors, concentration detectors and differential pressure gauges at different locations in the flue. Specifically, a first set of temperature sensors and an SO2 concentration detector are installed at the front end of the precooling zone to acquire initial temperature distribution data and initial pollutant concentration data at the precooling zone inlet; a second set of temperature sensors and a differential pressure gauge are installed in the middle of the main reaction zone to acquire temperature change data and pressure loss data during the reaction process; a third set of concentration detectors are arranged at the end of the main reaction zone to acquire intermediate pollutant concentration data after the reaction; and a fourth set of temperature sensors and concentration detectors are installed at the outlet of the post-treatment zone to acquire final emission temperature data and final pollutant concentration data. The initial temperature distribution data, initial pollutant concentration data, temperature change data, pressure loss data, intermediate pollutant concentration data, final emission temperature data, and final pollutant concentration data are integrated and processed to form a complete real-time operating database. It should be noted that in this case study of a multi-zone monitoring system for the flue gas of a 300MW coal-fired boiler, the boiler's tail flue is divided into three main parts: a precooling zone, a main reaction zone, and a post-treatment zone. The specific configuration of the monitoring system is as follows: Monitoring points at the pre-cooling zone inlet: Three K-type thermocouple temperature sensors (range 0-600℃, accuracy ±1.5℃) and two laser in-situ SO2 concentration detectors were installed at the center of the flue gas section at the front end of the pre-cooling zone and on both side walls. The sensors collected data at a frequency of once per second, and the initial flue gas temperature was found to be stable at 325±5℃, with an average initial SO2 concentration of 850 mg / m³. 3 These data serve as the initial temperature and pollutant concentration baselines for the system. Monitoring point in the middle of the main reaction zone: Five temperature sensors and one differential pressure gauge were installed before and after the catalyst bed in the main reaction zone. The temperature sensors detected that the exothermic reaction caused the temperature to rise from 300℃ to 315℃, while the differential pressure gauge showed a pressure loss of 480 Pa in the catalyst bed. This data is used to determine whether the catalyst has become clogged or accumulated ash. Monitoring point at the end of the main reaction zone: A multi-component concentration detector (using ultraviolet differential absorption spectroscopy) was installed here, collecting data every 30 seconds. Monitoring showed that after preliminary desulfurization and denitrification, the SO2 concentration dropped to 120 mg / m³. 3 NO x Concentration reduced to 80 mg / m³ 3 This reflects the treatment effect of the main reaction zone.

[0047] Post-treatment area outlet monitoring point: A fourth set of monitoring equipment was installed before the final emission outlet of the flue gas duct, including two temperature sensors and one dust concentration detector. Data shows that after subsequent purification, the flue gas temperature dropped to 125℃ (below the acid dew point, requiring attention to corrosion prevention), and the dust concentration was below 10mg / m³. 3The emission standards are met. Data integration and transmission: All sensor data is transmitted to a real-time database in the central control room (using time-series database software) via 4-20mA analog signals and Modbus communication protocol. The database is updated every second, generating historical trend charts containing 20 parameters such as temperature, concentration, and pressure difference, providing data support for subsequent optimized control.

[0048] 202. Based on real-time operating data, establish a control model that includes three parameters: desulfurizing agent injection rate, catalyst activity, and reaction temperature, and generate optimized control parameters; Specifically, a desulfurizer demand analysis model is established, and the desulfurizer demand parameters are calculated based on initial pollutant concentration data and intermediate pollutant concentration data; a catalyst activity evaluation model is constructed, and the catalyst compensation parameters are analyzed based on temperature change data and pressure loss data; a temperature coordination control model is designed, and temperature regulation parameters are generated based on initial temperature distribution data and final emission temperature data; the desulfurizer demand parameters, catalyst compensation parameters, and temperature regulation parameters are coupled and analyzed to form a system coordination control scheme; based on the system coordination control scheme, an optimized control parameter set including the precise dosage of desulfurizer, catalyst replenishment rate, and temperature setpoint is generated. Furthermore, a control model is established that includes three parameters: desulfurizer injection rate, catalyst activity, and reaction temperature. This model also includes: establishing a reaction efficiency model for the desulfurizer in different temperature ranges based on the principle of multi-stage reaction kinetics, generating a staged reaction scheme; establishing a catalyst activity decay compensation model based on the flue gas composition variation characteristics, generating a catalyst activity maintenance strategy; establishing a temperature field distribution optimization model combined with flue gas flow characteristics, generating a temperature gradient control scheme; coupling the staged reaction scheme with the temperature gradient control scheme to form a precise desulfurizer dosing strategy; and synergistically integrating the catalyst activity maintenance strategy with the precise desulfurizer dosing strategy to form a system operation optimization scheme. It should be noted that, based on the real-time operational data collected in step 201, a control model is established that includes three parameters: desulfurizing agent injection rate, catalyst activity, and reaction temperature. Based on the initial SO2 concentration (850 mg / m³) collected at the inlet of the pre-cooling zone... 3 The concentration of intermediate SO2 detected at the end of the main reaction zone (120 mg / m³) was compared with that of the intermediate SO2 concentration detected at the end of the main reaction zone. 3 The desulfurization efficiency is currently calculated to be 85.9%. Further efforts are needed to reduce the outlet SO2 concentration to 50 mg / m³. 3 Below the target emission value, the model is based on a flue gas flow rate of 1.2 × 10⁻⁶. 6 m 3Based on the stoichiometric ratio and the reaction rate, the required precise dosage of desulfurizing agent (taking Ca(OH)2 as an example) should be 2.8 t / h. This calculation takes into account the difference between the initial concentration and the target concentration, as well as the safety factor set by the system (1.1 times the theoretical requirement to cope with concentration fluctuations).

[0049] In this embodiment, the catalyst activity sub-model is specifically formulated as follows: in, The current activity coefficient (0-1); Use 1.0 as the initial activity baseline. The differential pressure value is monitored in real time. The reference pressure difference is 300 Pa. The maximum permissible pressure difference (1000 Pa); Cumulative running time; Design life; , These are weighting coefficients (taken as 0.4 and 0.6 respectively). When the calculated... When the value is less than 0.6, the system determines that the activity is insufficient and triggers an early warning. The model analysis included temperature data in the middle of the main reaction zone (showing that the reaction was exothermic, causing the temperature to rise from 300℃ to 315℃) and differential pressure gauge data (showing that the pressure loss of the catalyst bed was 480Pa).

[0050] A pressure difference-activity comparison table is included in the catalyst activity evaluation model. (Base pressure difference) =300Pa corresponds to 100% activity. The model monitors the pressure difference in real time. and the reaction exothermic temperature .

[0051] Activity decay rate .

[0052] In this embodiment, the pressure difference was monitored to rise to 480 Pa, and the temperature rise was reduced from the design value of 15°C to 12°C. Substituting these values ​​into the calculation, the total attenuation rate was found to be approximately 25%, meaning that the current activity is 75% of the initial activity.

[0053] To maintain a denitrification efficiency of over 92%, the catalyst activity assessment model outputs catalyst compensation parameters. It is recommended to set the catalyst replenishment rate to 5 kg / h to compensate for activity decay and ensure reaction efficiency.

[0054] Based on the inlet flue gas temperature of the pre-cooling zone (325℃) and the optimal reaction temperature window set by the system (280-300℃), the model calculates that the flue gas needs to be cooled by approximately 35℃. Simultaneously, to ensure that the outlet flue gas temperature of the post-treatment zone remains stable at 125℃ (to avoid low-temperature corrosion and meet emission requirements), the model integrates the flue gas recirculation ratio and heat exchanger power to generate temperature regulation parameters: instructing the flue gas recirculation damper opening to be adjusted to 40%, and setting the heat exchanger power to 850kW, in order to precisely control the reaction temperature field.

[0055] The logic for generating temperature regulation parameters is as follows: the system first calculates the target temperature to be maintained. Total enthalpy change required If heating is required ( If the power is >0, prioritize increasing the heat exchanger power; if the heat exchanger is still insufficient even at 100% power, then reduce the flue gas recirculation ratio (to reduce the mixing of low-temperature flue gas). If cooling is required ( If the value is less than 0, the flue gas recirculation ratio is increased first; when the recirculation ratio reaches the upper limit (40%), the heat exchanger power is reduced. In this embodiment, the calculation result falls within the cooling range, so the command is generated: flue gas recirculation damper opening 40%, heat exchanger power 850kW.

[0056] The control system performs coupled analysis on the above-mentioned desulfurizer demand parameters, catalyst compensation parameters, and temperature regulation parameters. Taking into account the influence of temperature on the desulfurization reaction efficiency (too low a temperature will reduce the Ca(OH)2 reaction rate), the model will fine-tune the water spray volume in the pre-cooling zone to ensure that the temperature of the flue gas entering the main reaction zone is not lower than 280℃.

[0057] The specific logic is as follows: the desulfurization reaction rate constant decreases as the temperature T decreases. A temperature correction coefficient curve is preset within the control system. .

[0058] Revised desulfurizer demand .

[0059] For example, when the temperature in the precooling zone is monitored to be 10°C below the optimal reaction temperature, The automatic value is set to 1.1, meaning the model commands the desulfurizer injection amount to increase by 10% based on the theoretical value to compensate for the decrease in reaction rate caused by low temperature, thus achieving coupled control of temperature and injection amount. An optimized set of control parameters was generated: the precise dosage of desulfurizing agent was 2.8 t / h, the catalyst replenishment rate was 5 kg / h, and the main reaction zone temperature was set at 290℃. This parameter set ensured efficient removal of pollutants, long-term stable operation of the catalyst, and efficient utilization of system thermal energy.

[0060] 203. Input the optimized control parameters into the central control system, and adjust the desulfurizing agent injection device, catalyst replenishment system and temperature control equipment through the PLC controller to form coordinated control commands; Specifically, the precise dosage of desulfurizing agent is converted into a control signal for the desulfurizing agent injection device, generating a multi-stage injection command that includes the injection amount in the precooling zone and the injection amount in the main reaction zone; the catalyst replenishment rate is converted into a drive signal for the catalyst replenishment system, generating a catalyst replenishment command that includes the conveying speed and the dosage; and the temperature setpoint is converted into a regulation signal for the temperature regulation device, generating a temperature regulation command that includes the flue gas recirculation ratio and the heat exchanger power. The process of converting the temperature setpoint into an adjustment signal uses a combination of table lookup and feedback control. The system stores a static correspondence table of "temperature-damper opening-heat exchange power". Upon receiving the setpoint of 290℃, the system first looks up the basic opening: recirculation damper 35%, heat exchanger power 800kW. Then, based on the outlet temperature feedback, the PID module dynamically fine-tunes the above basic values, generating specific execution instructions that include the flue gas recirculation ratio (40%) and heat exchanger power (850kW). The time sequence coordination module of the PLC controller integrates multi-level injection commands, catalyst replenishment commands, and temperature control commands in a time sequence to form a time-synchronized coordinated control command set. Based on the coordinated control command set, the action sequence table and parameter set values ​​of each actuator are generated to complete the coordinated control configuration of the entire exhaust gas treatment system. Furthermore, through the time sequence coordination module of the PLC controller, multi-level injection commands, catalyst replenishment commands, and temperature control commands are integrated in a time sequence to form a time-synchronized coordinated control command set. This includes: establishing the time sequence control logic of the multi-level injection system, setting the desulfurizer injection time interval between the precooling zone and the main reaction zone based on the flow velocity of the flue gas in the flue, and generating a desulfurizer injection time sequence scheme; designing the progressive control logic of the catalyst replenishment system, setting the start-up and shutdown time sequence of the screw conveyor based on the pressure drop trend of the catalyst bed, and generating a catalyst replenishment time sequence scheme; constructing the hierarchical control logic of the temperature control system, setting the linkage control sequence between the flue gas recirculation system and the heat exchanger based on the flue gas temperature change rate, and generating a temperature control time sequence scheme; aligning the desulfurizer injection time sequence scheme, catalyst replenishment time sequence scheme, and temperature control time sequence scheme on the time axis to form a system-level time sequence coordinated control framework; and generating a time-stamped coordinated control command set based on the time sequence coordinated control framework, and converting this command set into an action time sequence table for each actuator. It should be noted that, based on the optimized control parameters generated in step 202 (precise desulfurizer dosage 2.8 t / h, catalyst replenishment rate 5 kg / h, main reaction zone temperature setpoint 290℃), the parameters are converted into specific execution instructions by a PLC controller (Mitsubishi FX2N PLC) and integrated into a time-synchronized coordinated control instruction set: The desulfurizer dosage of 2.8 t / h is converted into distribution instructions for the precooling zone and the main reaction zone: the coarse injection rate in the precooling zone is set to 1.2 t / h, and the frequency converter of the screw feeder valve is adjusted to 35 Hz via a 4-20mA signal output from the PLC to form an alkaline atomization zone; the fine injection rate in the main reaction zone is set to 1.6 t / h, corresponding to a frequency converter frequency of 45 Hz, to generate a directional injection flow field. The timing logic is based on a flue gas velocity of 8 m / s and a distance of 15 meters from the precooling zone to the main reaction zone, calculating an injection time interval of 1.9 seconds to ensure that the desulfurizer arrives at the main reaction zone synchronously with the flue gas.

[0061] The catalyst replenishment rate is 5 kg / h. The screw conveyor is controlled by a PLC drive signal: the conveyor motor speed is set to 120 rpm, and the dosage is increased in increments of 0.1 kg / min. The start-stop sequence is set according to the catalyst bed pressure difference (real-time value 480 Pa, threshold 500 Pa alarm): it runs for 10 minutes every 2 hours to prevent blockage.

[0062] The temperature setpoint of 290℃ is converted into an execution signal: the opening of the flue gas recirculation damper is adjusted to 40%, and the electric actuator is controlled through the PLC analog output module; the heat exchanger power is set to 850kW, and the damper is linked according to the temperature change rate (>5℃ / min), and the power is gradually increased within 30 seconds to avoid sudden changes.

[0063] The PLC time sequence coordination module (FX2N-4A / D module) aligns three types of instructions with the time axis: desulfurizer injection sequence: injection in the main reaction zone starts 1.9 seconds after injection in the precooling zone; catalyst replenishment sequence: replenishment starts immediately when the pressure difference exceeds 450Pa, otherwise it runs in a 2-hour cycle; temperature regulation sequence: damper and heat exchanger power adjustment are triggered synchronously, with a response time ≤5 seconds.

[0064] The system generates a time-stamped instruction set, converts it into a timing table for the actions of each actuator (0 seconds to open the damper → 1.9 seconds to start the main injection → 120 minutes to add catalyst), and sends it to the field equipment via the PLC communication module (RS-485).

[0065] 204. According to the coordinated control instructions, control the injection position and injection amount of desulfurizing agent in the flue, while adjusting the distribution density of catalyst in the reactor and controlling the heat exchange rate of the heat exchanger. Specifically, the process involves: performing coarse injection in the precooling zone, forming an alkaline atomization zone based on the injection volume in the precooling zone according to the multi-stage injection command, and generating preliminary desulfurization products; performing fine injection in the main reaction zone, forming a directional injection flow field based on the injection volume in the main reaction zone according to the multi-stage injection command, and generating deep desulfurization products; adjusting the catalyst dosage ratio in different reaction zones according to the catalyst replenishment command via a screw conveyor to form a gradient catalyst bed and generate an optimized reaction environment; controlling the damper opening of the flue gas recirculation system according to the temperature control command to generate a stable flue gas mixing flow field; and simultaneously adjusting the heat exchanger's operating power based on the heat exchanger power parameters in the temperature control command to generate a precisely controlled reaction temperature field. It should be noted that, based on the coordinated control command set generated in step 203 (desulfurizer precooling zone injection rate 1.2t / h, main reaction zone injection rate 1.6t / h, catalyst replenishment rate 5kg / h, main reaction zone temperature setpoint 290℃), the field actuators are driven by a PLC controller (Siemens S7-300 series) to achieve precise coordinated control of desulfurizer injection, catalyst distribution, and temperature field. Pre-cooling zone coarse injection: Based on the pre-cooling zone injection rate (1.2t / h) in the multi-stage injection command, the PLC outputs a 4-20mA analog signal to the frequency converter of the pre-cooling zone spray gun, adjusting the feed valve frequency to 35Hz. The spray gun atomizes the limestone slurry into droplets with a particle size of 50-100μm at a pressure of 0.5MPa, forming an alkaline atomization zone in the pre-cooling zone. This stage can initially remove about 30% of SO2, generating calcium sulfite particles.

[0066] Fine injection in the main reaction zone: After 1.9 seconds of flue gas flow, the PLC triggers the injection command for the main reaction zone (1.6t / h), adjusting the frequency converter to 45Hz. The spray gun uses a swirling nozzle to form a directional injection flow field under a pressure of 0.8MPa, ensuring that the desulfurizing agent is fully mixed with the flue gas, further removing SO2, and achieving a cumulative desulfurization efficiency of over 90%.

[0067] According to the catalyst replenishment command (5 kg / h), the PLC controls the screw conveyor to operate at a speed of 120 rpm. By adjusting the addition ratio of different reaction zones (40% in the front zone, 35% in the middle zone, and 25% in the rear zone), a bed with a catalyst concentration gradient distribution (density gradient of 0.8-1.2 g / cm³) is formed. 3 This distribution optimizes the reaction pathway, reduces the catalyst activity decay rate to <2% per month, and controls the bed pressure differential to remain stable at 450-500 Pa.

[0068] Flue gas recirculation control: Based on temperature control commands, the PLC adjusts the damper opening of the flue gas recirculation system to 40%, mixing approximately 15% of the low-temperature flue gas (125℃) into the main flue, suppressing local high-temperature zones, and narrowing the temperature fluctuation range of the flue gas mixing flow field to ±5℃. Heat exchanger power regulation: The heat exchanger power is synchronously controlled at 850kW, and the heat exchange rate is dynamically adjusted through a PID algorithm to ensure the temperature of the main reaction zone remains stable at 290±2℃ (optimal reaction window). The temperature field uniformity coefficient (defined as the ratio of the standard deviation to the mean of the effective reaction zone temperature) is controlled below 0.05, calculated using the following formula: in For temperature standard deviation, This represents the average temperature.

[0069] Through time-series coordination (see table below), the three types of control actions are precisely aligned on the time axis, avoiding equipment interference or resource conflicts. This ultimately achieves an SO2 emission concentration of <50 mg / m³. 3 Temperature control deviation ≤ ±2℃, catalyst utilization rate increased by 15%, and the actuator action sequence and parameters are shown in Table 6 below: Table 6 205. The concentration of pollutants in the exhaust gas is detected in real time by an online monitoring device installed at the flue outlet, and the detection results are fed back to the central control system to dynamically adjust the desulfurizing agent injection volume and catalyst replenishment rate. Specifically, SO2 concentration monitoring data is acquired in real time using a laser analyzer in the online monitoring device, generating an SO2 concentration trend graph; NO concentration is acquired in real time using a chemiluminescence analyzer in the online monitoring device. x Concentration monitoring data, generating NO x Concentration distribution curve; real-time dust concentration monitoring data is acquired through a particulate matter counter in an online monitoring device, generating a dust concentration monitoring report; SO2 concentration change trend chart, NO... x The concentration distribution curve and dust concentration monitoring report are comprehensively analyzed to generate an emission quality assessment report. Based on the emission quality assessment report and the preset emission standard limits, the system operation status diagnosis results are generated. According to the system operation status diagnosis results, the desulfurizing agent injection quantity correction command and catalyst replenishment rate adjustment command are generated through the adaptive adjustment module of the central control system. The desulfurizing agent injection quantity correction command and catalyst replenishment rate adjustment command are sent to the PLC controller to realize real-time dynamic adjustment of the desulfurizing agent injection device and catalyst replenishment system. It should be noted that the concentration of pollutants in the exhaust gas is monitored in real time by an online monitoring device installed at the flue outlet, and the results are fed back to the central control system to dynamically adjust the desulfurizing agent injection volume and catalyst replenishment rate, thereby achieving closed-loop control. SO2 concentration monitoring: A pulsed ultraviolet fluorescence SO2 analyzer (Thermo Scientific 43i) was used, with data collected every 10 seconds. Monitoring showed that the outlet SO2 concentration was 65 mg / m³. 3 Gradually rose to 78 mg / m 3 (The threshold value for exceeding the standard is 50 mg / m³) 3 ), generating a concentration change trend graph (slope +0.15mg / m³). 3 ·min). NO x Concentration monitoring: NO concentration was monitored using a chemiluminescence method. x The analyzer (Thermo Scientific 42i model) performs real-time detection of NO. x The concentration remained stable at 45 mg / m³ 3 However, the fluctuation range widened to ±5 mg / m 3 (Standard limit 50 mg / m²) 3 Dust concentration monitoring: The laser scattering particulate counter showed a dust concentration of 12 mg / m³. 3 (Standard limit 10 mg / m²) 3 The monitoring report generated indicated that particulate matter levels exceeded the standard by 20%.

[0070] The three types of data are integrated into an emissions quality assessment report, including: SO2 exceedance index: (78-50) / 50×100%=56%; NO x Stability coefficient: (fluctuation range / standard limit) = 5 / 50 = 0.1; Dust exceedance rate: (12-10) / 10×100% = 20%. Based on the report generation system operation status diagnosis results: the desulfurizing agent reaction efficiency is insufficient (SO2 removal rate drops to 85%), and the catalyst activity is degraded (bed pressure difference rises to 520Pa), requiring immediate adjustment.

[0071] Based on the diagnostic results, the correction amount is calculated using the following feedback control formula: in, For correction amount, =0.8 is the proportionality coefficient. =0.05 is the integral coefficient. and These represent the actual and target concentrations, respectively. Calculations show that the desulfurizer injection rate needs to be increased by 0.3 t / h (from the original 2.8 t / h), and the catalyst replenishment rate needs to be increased to 6 kg / h (from the original 5 kg / h) to compensate for the activity decay.

[0072] The desulfurizer injection quantity correction command is calculated using a discrete incremental PID algorithm, and the correction amount is... The calculation formula is: in: Let be the concentration deviation at the k-th sampling time; for the desulfurizer injection system, set =0.8, =0.05, =0.1. When When, deviation If positive, the calculated For a positive value, the injection rate is increased. For the catalyst replenishment system, the same algorithm structure is used, but with an independent coefficient setting (0.2) to accommodate its different response characteristics. Through discretization calculations, the system directly outputs specific adjustment increment values ​​in each sampling cycle, thereby achieving precise dynamic correction.

[0073] The correction command was issued to the actuators via the PLC controller: the frequency of the desulfurizing agent injection device's inverter was increased from 35Hz to 38Hz, and the injection rate in the precooling zone was adjusted to 1.3t / h; the speed of the screw conveyor was increased from 120rpm to 130rpm, ensuring that the catalyst bed pressure differential returned to below 480Pa. Within 30 minutes after the adjustment, monitoring data showed that the SO2 concentration dropped to 48mg / m³. 3 Dust concentration dropped to 9 mg / m³ 3 The system has stabilized.

[0074] The core parameters during the dynamic adjustment process are recorded in Table 7 below: Table 7 206. An ash and slag treatment system is set up after the desulfurization reaction system to collect the reaction byproducts generated during the desulfurization process and generate mixed ash and slag. The mixed ash and slag is transported to a hydraulic separation device, where it undergoes multi-stage sedimentation and filtration to obtain solid filter cake and clarified filtrate. The solid filter cake is transported to a solidification and molding device, where a solidifying agent and stabilizer are added to prepare it into environmentally friendly building material raw materials. The clarified filtrate is introduced into a neutralization reaction tank to adjust the pH value to the neutral range, obtaining compliant reclaimed water. The compliant reclaimed water is transported to the spray system in the pre-cooling zone for recycling as cooling spray water. Specifically, environmentally friendly building material raw materials are transported to molding and pressing equipment, and molded into standard-sized building blocks. The building blocks are then sent to a steam curing kiln for curing in a constant temperature and humidity environment to obtain finished building materials with specified strength. Some of the finished building materials are used for the construction and maintenance of boiler room auxiliary buildings, forming an internal recycling of building materials. A portion of the compliant recycled water is introduced into the boiler feedwater system, and after further purification, it serves as a supplementary source of boiler feedwater. The low-temperature waste heat generated during desulfurization is recovered through a heat exchanger and used to preheat the air entering the boiler, forming a cascade utilization system of thermal energy. It should be noted that the ash and slag characteristics are as follows: the mixed ash and slag produced by the desulfurization system is 6.5 t / h, mainly composed of CaSO3 (50%), CaSO4 (20%), and free CaO (20%). This is then separated by a hydraulic separation device (processing capacity 200 m³ / h). 3 The ash residue and industrial wastewater are mixed at a water-ash ratio of 1:4 to form a slurry. After multi-stage sedimentation, the solid filter cake has a moisture content of ≤30% and a calcium ion concentration of 1,200 mg / L; the clarified filtrate has suspended solids of ≤50 mg / L and a pH of ≈10.5 (alkaline).

[0075] Neutralization reaction tank operation: The clarified filtrate is introduced into the neutralization reaction tank (volume 50m³). 3 ), and introduce flue gas (CO2 concentration 12%, flow rate 1,800 m³ / h) into the tail end of the boiler. 3 / h). Control conditions: reaction time t=1.5h, pH adjusted to 7.5 (controlled by CO2 dosage); temperature maintained at 50℃ (utilizing waste heat from flue gas).

[0076] CO2 solidification efficiency formula: An empirical formula is constructed based on reaction kinetic experimental data. Where: η is the CO2 curing efficiency (range 0-1); k=0.0015 is an empirical constant, unit L / (mg·h); effective range: pH value controlled between 6.5 and 9.0, calcium ion concentration... The concentration should be controlled between 500 and 2000 mg / L, and the reaction time t should be controlled between 0.5 and 3 hours; [Ca 2+ The concentration of calcium ions in the filtrate is 1200 mg / L; the reaction time is t = 1.5 h; and the pH is 7.5. =7.0 is the reference pH.

[0077] Calculation example: , That is, 94.5%.

[0078] Solid filter cake building materials: Filter cake is solidified with 5% cement and pressed into building blocks (compressive strength 15MPa), disposing of 2,000 tons of ash and slag annually. Filtrate reuse: 70% of the neutralized filtrate (pH=7.0±0.3, hardness ≤150mg / L) is reused for pre-cooling zone spraying, and 30% is purified and used as boiler feedwater, saving 300,000 tons of water annually. Waste heat recovery: Low-temperature flue gas waste heat (90℃→50℃) is used to preheat boiler intake air through a heat exchanger, saving 600 tons of standard coal annually.

[0079] In this embodiment of the invention, a control model is established based on real-time operating data, incorporating three parameters: desulfurizer injection rate, catalyst activity, and reaction temperature. This model is further subdivided into multiple sub-models. Through comprehensive coupling analysis of these models, an optimized control parameter set is generated, including precise desulfurizer dosage, catalyst replenishment rate, and temperature setpoint. This fully considers the interrelationships between parameters and allows for real-time adjustment of the control strategy according to actual operating conditions. This achieves efficient pollutant removal, long-term stable catalyst operation, and efficient utilization of system thermal energy, improving the overall treatment efficiency and performance of the exhaust gas treatment system. It also avoids conflicts between actuators, ensuring precise temporal and spatial coordination of desulfurizer injection, catalyst replenishment, and temperature regulation, thus improving the system's collaborative control accuracy and operational efficiency. An online monitoring device installed at the flue outlet continuously monitors the pollutant concentration in the exhaust gas and feeds the results back to the central control system. Based on the emission quality assessment report and preset emission standard limits, the system operation status diagnosis results are generated. Then, through the adaptive adjustment module of the central control system, the desulfurizing agent injection quantity correction command and catalyst replenishment rate adjustment command are generated to realize real-time dynamic adjustment of the desulfurizing agent injection device and catalyst replenishment system. An ash and slag treatment system is set up to treat the reaction by-products generated during the desulfurization process through multi-stage sedimentation, filtration, solidification and molding, etc., to prepare environmentally friendly building material raw materials, realize the resource utilization of ash and slag, reduce the emission of solid waste, and reduce environmental pollution. The qualified recycled water is recycled for pre-cooling zone spraying and boiler feedwater, and the low-temperature waste heat in the desulfurization process is recovered for preheating boiler intake air, forming a thermal energy cascade utilization system. This realizes the efficient recycling of water resources and thermal energy, reduces production costs, and has good economic and environmental benefits.

[0080] Figure 4 This is a schematic diagram of a boiler exhaust gas treatment device provided in an embodiment of the present invention. The device 300 may include: a processor 301, a receiver 302, a transmitter 303, and a memory 304. The receiver 302, transmitter 303, and memory 304 are respectively connected to the processor 301 via a bus. It should be noted that in some possible implementations, the processor 301 and the memory 303 may be integrated together.

[0081] The processor 301 includes one or more processing cores. The processor 301 executes the methods performed by the base station in the random access method provided in this application embodiment by running software programs and modules. The memory 304 can be used to store software programs and modules. Specifically, the memory 304 can store an operating system 3041 and at least one application module 3042 required for a function. The receiver 302 is used to receive communication data sent by other devices, and the transmitter 303 is used to send communication data to other devices.

[0082] The present invention also provides a boiler exhaust gas treatment device, which includes a memory and a processor. The memory stores computer-readable instructions. When the computer-readable instructions are executed by the processor, the processor performs the steps of the boiler exhaust gas treatment method in the above embodiments.

[0083] The present invention also provides a computer-readable storage medium, which can be a non-volatile computer-readable storage medium or a volatile computer-readable storage medium, wherein the computer-readable storage medium stores instructions that, when the instructions are executed on a computer, cause the computer to perform the steps of the boiler exhaust gas treatment method.

[0084] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0085] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0086] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for treating boiler exhaust gas, characterized in that, include: A multi-zone reaction system is established in the boiler tail flue, and real-time operating data of the tail gas treatment process is obtained by temperature sensors, concentration detectors and differential pressure gauges arranged at different positions in the flue. Based on real-time operational data, a control model is established, including three parameters: desulfurizing agent injection rate, catalyst activity, and reaction temperature, to generate optimized control parameters. Based on optimized control parameters, the desulfurizing agent injection device, catalyst replenishment system, and temperature control equipment are adjusted separately through a PLC controller to form coordinated control commands. According to the coordinated control instructions, the injection position and injection amount of desulfurizing agent in the flue are controlled, while the distribution density of catalyst in the reactor is adjusted, and the heat exchange rate of the heat exchanger is controlled.

2. The boiler exhaust gas treatment method according to claim 1, characterized in that, include: The first set of temperature sensors and SO2 concentration detectors are installed at the front end of the precooling zone to obtain the initial temperature distribution data and initial pollutant concentration data at the entrance of the precooling zone. A second set of temperature sensors and differential pressure gauges are installed in the middle of the main reaction zone to acquire temperature change data and pressure loss data during the reaction process. A third set of concentration detectors is placed at the end of the main reaction zone to obtain data on the concentration of intermediate pollutants after the reaction. A fourth set of temperature sensors and concentration detectors is installed at the outlet of the aftertreatment zone to obtain the final emission temperature data and the final pollutant concentration data. The initial temperature distribution data, initial pollutant concentration data, temperature change data, pressure loss data, intermediate pollutant concentration data, final emission temperature data, and final pollutant concentration data are integrated and processed to form a real-time operating database.

3. The boiler exhaust gas treatment method according to claim 2, characterized in that, Based on the initial pollutant concentration data and the intermediate pollutant concentration data, the desulfurizer requirement parameters are calculated. A catalyst activity evaluation model was constructed, and catalyst compensation parameters were obtained based on the temperature change data and pressure loss data. Based on the initial temperature distribution data and the final emission temperature data, temperature regulation parameters are generated; Based on the desulfurizer demand parameters, catalyst compensation parameters, and temperature regulation parameters, a coupled analysis is performed to form a system coordinated control scheme; Based on the system coordination and control scheme, an optimized set of control parameters is generated, including the precise dosage of desulfurizing agent, catalyst replenishment rate, and temperature setpoint.

4. The boiler exhaust gas treatment method according to claim 3, characterized in that, Establish a reaction efficiency model for desulfurizing agents in different temperature ranges and generate a staged reaction scheme. Based on the characteristics of flue gas composition changes, a catalyst activity decay compensation model is established to generate a catalyst activity maintenance strategy. Based on the flue gas flow characteristics, an optimization model for temperature field distribution is established to generate a temperature gradient control scheme. Based on the coupled analysis of the staged reaction scheme and the temperature gradient control scheme, a precise desulfurization agent dosing strategy is formed; The catalyst activity maintenance strategy and the desulfurizer precise dosing strategy are synergistically integrated to form a system operation optimization scheme.

5. The boiler exhaust gas treatment method according to claim 3, characterized in that, include: The precise dosage of the desulfurizing agent is converted into a control signal for the desulfurizing agent injection device, generating multi-stage injection commands; The catalyst replenishment rate is converted into a driving signal for the catalyst replenishment system, thereby generating a catalyst replenishment command. Based on the temperature setpoint, a temperature control signal is converted into a temperature control device, generating a temperature control command. The multi-stage injection commands, catalyst replenishment commands, and temperature control commands are integrated in sequence to form a coordinated control command set.

6. The boiler exhaust gas treatment method according to claim 5, characterized in that, Based on the flow velocity of flue gas in the flue, the time interval between the desulfurizing agent injection in the precooling zone and the main reaction zone is set to generate a desulfurizing agent injection sequence scheme. Based on the pressure drop trend of the catalyst bed, the start-up and shutdown time sequence of the screw conveyor is set to generate a catalyst replenishment sequence scheme. Based on the rate of change of flue gas temperature, the linkage control sequence between the flue gas recirculation system and the heat exchanger is set to generate a temperature regulation timing scheme. The desulfurizer injection timing scheme, catalyst replenishment timing scheme, and temperature regulation timing scheme are processed to form a system-level timing coordination control framework. Based on the aforementioned timing coordination control framework, a coordination control instruction set is generated, and this instruction set is transformed into an action timing table for each actuator.

7. The boiler exhaust gas treatment method according to claim 5, characterized in that, include: Perform coarse injection operation in the precooling zone. According to the injection volume in the precooling zone in the multi-stage injection command, an alkaline atomization zone is formed in the precooling zone to produce preliminary desulfurization products. The main reaction zone fine injection operation is performed. According to the injection volume of the main reaction zone in the multi-stage injection command, a directional injection flow field is formed in the main reaction zone to generate deep desulfurization products. According to the catalyst replenishment command, the addition ratio of catalyst in different reaction zones is adjusted by a screw conveyor to form a catalyst bed and generate an optimized reaction environment; Based on the temperature control command, the opening of the damper of the flue gas recirculation system is controlled to generate a stable flue gas mixing flow field; The operating power of the heat exchanger is adjusted synchronously, and a precisely controlled reaction temperature field is generated based on the heat exchanger power parameters in the temperature control command.

8. The boiler exhaust gas treatment method according to claim 1, characterized in that, It also includes using online monitoring devices installed at the flue outlet to detect the concentration of pollutants in the exhaust gas in real time, obtaining the detection results and dynamically adjusting the desulfurizing agent injection volume and catalyst replenishment rate accordingly. Real-time acquisition of SO2 concentration monitoring data, and generation of SO2 concentration change trend graphs; Get NO in real time x Concentration monitoring data, generating NO x Concentration distribution curve; Real-time acquisition of dust concentration monitoring data and generation of dust concentration monitoring reports; The SO2 concentration change trend graph, NO x A comprehensive analysis of concentration distribution curves and dust concentration monitoring reports is conducted to generate an emission quality assessment report. Based on the emission quality assessment report and the preset emission standard limits, a system operation status diagnostic result is generated. Based on the system operation status diagnosis results, a desulfurizing agent injection quantity correction command and a catalyst replenishment rate adjustment command are generated; The desulfurizing agent injection quantity correction command and catalyst replenishment rate adjustment command are sent to the PLC controller to realize real-time dynamic adjustment of the desulfurizing agent injection device and catalyst replenishment system.

9. The boiler exhaust gas treatment method according to claim 8, characterized in that, The correction amount in the desulfurizer injection quantity correction instruction is : in, For correction amount, This is the proportionality coefficient. The integral coefficient is... and These are the actual concentration and the target concentration, respectively.

10. The boiler exhaust gas treatment method according to claim 1, characterized in that, Also includes: Collect the reaction byproducts generated during the desulfurization process to produce mixed ash residue; The mixed ash residue is transported to a hydraulic separation device, where it undergoes multi-stage sedimentation and filtration to obtain a solid filter cake and a clarified filtrate. The solid filter cake is conveyed to a curing and molding equipment, where a curing agent and a stabilizer are added to prepare an environmentally friendly building material raw material. The clarified filtrate is introduced into a neutralization reaction tank, and the pH value is adjusted to the neutral range to obtain qualified reclaimed water. The qualified recycled water is transported to the spray system in the pre-cooling zone for reuse as cooling spray water.

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