Partitioned precise ammonia spraying system for boiler flue

Abstract

The invention provides a boiler flue zoning precise ammonia spraying system, and relates to the technical field of boiler flue ammonia spraying, the boiler flue zoning precise ammonia spraying system comprises a denitration flue, an ammonia spraying system and a measuring system; the denitration flue comprises a denitration inlet flue and a denitration outlet flue, the denitration inlet flue and the denitration outlet flue are each divided into a side A and a side B from the center of the flue to the two sides, and the inlet end of the denitration inlet flue communicates with an ammonia spraying mother pipe; ammonia spraying systems are separately arranged on the A side and the B side of the denitration inlet flue, and each ammonia spraying system is provided with four ammonia spraying pneumatic adjusting door groups one by one from the center of the flue to the two sides; the A side and the B side of the denitration outlet flue are each independently provided with a measuring system, the measuring systems are in a single-side four-partition mode, and the whole measuring systems are arranged side by side in the east-west direction of the section of the flue. According to the system, the phenomena of sudden increase and sharp increase of the ammonia spraying amount are reduced, the ammonia escape amount can be reduced under any working condition, the threat to safe operation of equipment in the tail flue is reduced, and the maintenance and operation cost of downstream equipment is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of boiler flue ammonia injection, and in particular to a boiler flue zone precise ammonia injection system. Background Art

[0002] Selective catalytic reduction (SCR) denitrification technology is widely used in flue gas pollution control of large-scale coal-fired power plants at home and abroad. It has the advantages of high denitrification efficiency, mature technology, and reliable operation. The denitrification system is usually composed of an ammonia injection device, a catalyst layer, a flue, etc. Its working principle is to inject nitrogen oxides (NO) into the flue gas within a certain temperature range. x ) is injected into the flue gas, and under the action of the catalyst, NO x Reduced to nitrogen and water, thus achieving the purpose of denitrification.

[0003] However, this technology also faces a series of challenges in practical application:

[0004] First, the denitrification system has a large geometric space, and the flue has bends and gradual size changes, which affect the uniformity of the system flow field and ammonia nitrogen concentration field, resulting in outlet NO x Uneven distribution and local ammonia escape. Secondly, increasing the number of catalyst layers and the amount of ammonia sprayed to meet ultra-low emission requirements will cause problems. Increasing the number of catalysts will increase the proportion of SO2 oxidized to SO3, and increasing the amount of ammonia sprayed will increase ammonia escape, prompting the formation of highly viscous and highly acidic ammonium bisulfate, causing air preheater blockage, induced draft fan corrosion and other problems that affect the safe and economical operation of the unit. Furthermore, the change in coal types leads to unstable coal quality, boiler combustion efficiency and NO x There are contradictions between emissions. NOx fluctuates greatly when the operating conditions change. It is necessary to accurately predict NOx under changing operating conditions. x The amount of generation is a difficult problem in optimizing the SCR ammonia injection control. Summary of the invention

[0005] In response to the above problems, the present application provides a boiler flue zone precise ammonia injection system, which changes the ammonia injection zone from "9 to 4", reduces the sudden increase and surge of ammonia injection amount, and reduces the ammonia escape rate.

[0006] To achieve the purpose of this application, this application provides the following technical solutions:

[0007] A boiler flue zone precise ammonia injection system, comprising: a denitrification flue, an ammonia injection system and a measurement system;

[0008] The denitrification flue comprises a denitrification inlet flue and a denitrification outlet flue, wherein the denitrification inlet flue is divided into a denitrification inlet flue A side and a denitrification inlet flue B side from the center of the flue, and the denitrification outlet flue is divided into a denitrification outlet flue A side and a denitrification outlet flue B side from the center of the flue, wherein the inlet ends of the denitrification inlet flue A side and the denitrification inlet flue B side are both connected with an ammonia injection mother pipe;

[0009] The A side of the denitrification inlet flue and the B side of the denitrification inlet flue are both separately provided with an ammonia injection system, and the ammonia injection system is arranged in the flue along the width of a single side of the flue;

[0010] The ammonia injection system is provided with four ammonia injection pneumatic adjustment door groups arranged one by one from the center of the flue to both sides, and each group of the ammonia injection pneumatic adjustment door groups includes an ammonia injection pneumatic adjustment door and manual doors of the same specifications but different quantities;

[0011] The A side of the denitrification outlet flue and the B side of the denitrification outlet flue are each provided with a separate measurement system, the measurement system adopts a single-side 4-zone form, and the single-side 4 zones are arranged in parallel along the east-west direction of the flue cross section as a whole;

[0012] The measurement system includes: multiple sampling probes and a CEMS system, each of the sampling probes corresponds to a single-side partition of the measurement system, and has the same number as the corresponding single zone of the measurement system, wherein on each side, the sampling probes with odd numbers are uniformly connected to the CEMS system, and the sampling probes with even numbers are uniformly connected to the CEMS system.

[0013] In a possible implementation, the ammonia injection pneumatic adjustment gate is arranged at the inlet of the denitration reactor, and a pneumatic regulating valve is used to control the manual gate in the group;

[0014] The manual doors distributed from the center of the flue to both sides are in groups of 4, 4, 3 and 3 respectively.

[0015] In a possible implementation, all of the multiple sampling probes arranged on the A side of the denitrification outlet flue are connected to the sampling power box on the A side, and all of the multiple sampling probes arranged on the B side of the denitrification outlet flue are connected to the sampling power box on the B side;

[0016] The A-side sampling power box and the B-side sampling power box are both connected to the distribution box via the on-site power supplies on both sides.

[0017] In a possible implementation, the A-side sampling power box and the B-side sampling power box are connected to a DCS control system via cables. The DCS control system is used to implement electrical control and data collection and transmission. The electrical control includes sampling control and purging control of the probe.

[0018] In a possible implementation, the A-side sampling power box and the B-side sampling power box also monitor the fault signal of the sampling probe at the same time, and transmit the fault signal to the DCS control system.

[0019] In a possible implementation, the plurality of sampling probes are respectively connected to a sampling valve, a sampling switching valve and a sampling valve, and the sampling valve, the sampling switching valve and the sampling valve are independently numbered, and the numbers are the same as the corresponding sampling probes.

[0020] In a possible implementation, each of the sampling probes is connected to a solenoid valve, wherein on each side, the solenoid valves of the sampling probes with odd numbers are connected, and the solenoid valves of the sampling probes with even numbers are connected.

[0021] In a possible implementation, compressed air is introduced into the A side of the denitrification outlet flue and the B side of the denitrification outlet flue through a compressed air pipe, and the compressed air pipe passes through each of the sampling probes and is also provided with a solenoid valve.

[0022] In a possible implementation, in the ammonia injection system, each pneumatic regulating valve is connected to a remote control instrument, and each of the remote control instruments in the ammonia injection system is connected to the MCS regulating control system;

[0023] In the measuring system, each solenoid valve is connected to a remote control instrument, and each of the remote control instruments in the measuring system is connected to the SCS sequential control system;

[0024] The ammonia injection pneumatic adjustment door opening refers to the measured value of the measurement system and is automatically adjusted by the MCS regulation control system.

[0025] In a possible implementation, it further includes: a fume extraction pump installed on.

[0026] The advantages of this application are:

[0027] 1. This system reduces the sudden increase and surge of ammonia injection, making the variation range of NOx at the denitrification outlet less than ±5mg / m under stable working conditions. 3 , the NOx fluctuation of net flue gas outlet is reduced by more than 30%, reducing the risk of exceeding the standard and ensuring environmental protection, economic and social benefits;

[0028] 2. Under any operating condition, the ammonia escape rate of this system is not more than 2.3mg / Nm3 (standard state, dry basis, 6% oxygen);

[0029] 3. This system can also reduce the threat to the safe operation of equipment in the tail flue and reduce the maintenance and operation costs caused by corrosion and blockage of downstream equipment;

[0030] In summary, the present application changes the previous automatic control strategy of "PID+feedforward control mode, taking the NOx concentration of the flue gas at the SCR inlet as the feedforward value to control the total amount of SCR ammonia injection", and determines the new technical solution of "enhancing the adaptability of ammonia injection to changes in operating conditions through denitrification main valve feedforward control and denitrification zone refined ammonia injection control", thereby achieving rapid, accurate and smooth full-load regulation of the SCR system to adapt to the new peak-shaving and frequency-regulation background. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings are used to provide a further understanding of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation to the present application.

[0032] Figure 1 A schematic diagram of the structure of a boiler flue zone precise ammonia injection system provided in an embodiment of the present application;

[0033] Figure 2 A schematic diagram of the structure of the ammonia injection main pipe provided in an embodiment of the present application;

[0034] Figure 3 A schematic diagram of cable connection provided in an embodiment of the present application;

[0035] Figure 4 A detailed schematic diagram of the flue gas analysis process provided in the embodiment of the present application;

[0036] In the figure:

[0037] 1- ammonia injection main pipe; 2- denitrification main valve; 3- remote control instrument; 4- pneumatic regulating valve; 5- manual door; 6- ammonia injection branch pipe; 7- solenoid valve. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0039] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of this application, unless otherwise specified, "plurality" means two or more.

[0040] Example 1

[0041] See also Figure 1-3 , the present application provides a boiler flue zone precise ammonia injection system, comprising: a denitrification flue, an ammonia injection system and a measurement system;

[0042] The denitrification flue comprises a denitrification inlet flue and a denitrification outlet flue, wherein the denitrification inlet flue is divided into a denitrification inlet flue A side and a denitrification inlet flue B side from the center of the flue, and the denitrification outlet flue is divided into a denitrification outlet flue A side and a denitrification outlet flue B side from the center of the flue, wherein the inlet ends of the denitrification inlet flue A side and the denitrification inlet flue B side are both connected with an ammonia injection mother pipe 1;

[0043] The A side of the denitrification inlet flue and the B side of the denitrification inlet flue are both separately provided with an ammonia injection system, and the ammonia injection system is arranged in the flue along the width of a single side of the flue;

[0044] The ammonia injection system is provided with four ammonia injection pneumatic adjustment door groups arranged one by one from the center of the flue to both sides, and each group of the ammonia injection pneumatic adjustment door groups includes an ammonia injection pneumatic adjustment door and manual doors 5 of the same specifications but different quantities;

[0045] The A side and B side of the denitrification outlet flue are each provided with a separate measurement system, and the measurement system adopts a single-side 4-zone form. The measurement system on the A side of the denitrification outlet flue is respectively set as A1 zone, A2 zone, A3 zone and A4 zone, and the measurement system on the B side of the denitrification outlet flue is respectively set as B1 zone, B2 zone, B3 zone and B4 zone, and the single-side 4 zones are arranged in parallel along the east-west direction of the flue cross section as a whole;

[0046] The measurement system comprises: a plurality of sampling probes and a CEMS system, each of the sampling probes corresponds to a single-side partition of the measurement system, and has the same number as the corresponding single zone of the measurement system, wherein on each side, the sampling probes with odd numbers are uniformly connected to the CEMS system, and the sampling probes with even numbers are uniformly connected to the CEMS system;

[0047] Specifically, each measurement system single zone of the four zones on one side corresponds to one of the ammonia injection pneumatic adjustment door groups;

[0048] Specifically, the ammonia spray pneumatic adjustment gate is arranged on the ammonia spray branch pipe at the inlet of the denitration reactor, and a pneumatic regulating valve 4 is used to control the manual gate 5 in the group;

[0049] Specifically, the manual doors 5 distributed from the center of the flue to both sides are in groups of 4, 4, 3, and 3 respectively.

[0050] In a possible implementation, the plurality of sampling probes arranged on the A side of the denitrification outlet flue are all connected to the sampling power box on the A side, and the plurality of sampling probes arranged on the B side of the denitrification outlet flue are all connected to the sampling power box on the B side, and the sampling power box on the A side and the sampling power box on the B side are both connected to the distribution box through the on-site power supply on both sides;

[0051] Optionally, the power of the plurality of sampling probes is 200W;

[0052] Optionally, the power of the A-side sampling power box and the B-side sampling power box are both 600W.

[0053] In a possible implementation, the A-side sampling power box and the B-side sampling power box are connected to a DCS control system via cables. The DCS control system is used to implement electrical control and data collection and transmission. The electrical control includes sampling control and purging control of the probe.

[0054] In a possible implementation, the DCS control system sends an electrical control signal to the A-side sampling power box and the B-side sampling power box. After receiving the electrical control signal, the A-side sampling power box and the B-side sampling power box control the sampling probe to perform corresponding actions.

[0055] In a possible implementation manner, the A-side sampling power box and the B-side sampling power box also monitor the fault signal of the sampling probe at the same time, and transmit the fault signal to the DCS control system.

[0056] In a possible implementation, the plurality of sampling probes are respectively connected to a sampling valve, a sampling switching valve and a sampling valve, and the sampling valve, the sampling switching valve and the sampling valve are independently numbered, and the numbers are the same as the corresponding sampling probes.

[0057] In a possible implementation, during the sampling control process, first open the A1 and A2 sampling valves and the sampling switching valve 1 and the sampling switching valve 2, wait for T1 time, then close the A1 sampling valve, open the A3 sampling valve at the same time, and close the sampling switching valve 1 and the sampling switching valve 2. Then after T1 time, close the A2 sampling valve, open the A4 sampling valve, keep the sampling switching valve 1 open, open the sampling switching valve 2 again, and wait for T1 time. Then close the A3 sampling valve, open the B1 sampling valve, close the sampling switching valve 1 and the sampling switching valve 2, and wait for T1 time. Next, close the A4 sampling valve, open the B2 sampling valve, and also keep the sampling switching valve 1 and the sampling switching valve 2 open, and wait for T1 time. Then close the B1 sampling valve, open the B3 sampling valve, close the sampling switching valve 1 and the sampling switching valve 2, and wait for T1 time. Then close the B2 sampling valve, open the B4 sampling valve, and also keep the sampling switching valve 1 and the sampling switching valve 2 open, and wait for T1 time. Then close the B3 sampling valve, open the A1 sampling valve, close the sampling switching valve 1 and the sampling switching valve 2, and wait for T1 time. Finally, close the B4 sampling valve, open the A2 sampling valve, close the sampling switching valve 1 and the sampling switching valve 2, and wait for T1 time. After the whole process is completed, wait for T1 time, close the A1 sampling valve again, open the A3 sampling valve at the same time, close the sampling switching valve 1 and the sampling switching valve 2, and enter the sampling control cycle stage;

[0058] The T1 time is the specified switching time.

[0059] In a possible implementation, during the purge control process, the sampling valve is closed, the purge valve is opened, and after waiting for T3 time, the purge valve is closed;

[0060] Wherein, the T3 time is the prescribed purge time.

[0061] In a possible implementation manner, each of the sampling probes is respectively connected to a solenoid valve 7 , wherein on each side, the solenoid valves 7 of the sampling probes with odd numbers are connected, and the solenoid valves 7 of the sampling probes with even numbers are connected.

[0062] In a possible implementation, compressed air is introduced into the denitrification outlet flue A side and the denitrification outlet flue B side through compressed air pipes, and the compressed air pipes pass through each of the sampling probes and are also all provided with a solenoid valve 7.

[0063] In a possible implementation, in the ammonia injection system, each of the pneumatic regulating valves 4 is connected to a remote control instrument 3, and each of the remote control instruments 3 in the ammonia injection system is connected to the MCS regulating control system;

[0064] In the measurement system, each of the solenoid valves 7 is connected to a remote control instrument 3, and each of the remote control instruments 3 in the measurement system is connected to the SCS sequential control system;

[0065] Optionally, the remote control instrument 3 is arranged in an instrument cabinet of the CEMS room;

[0066] Optionally, each of the remote control instruments 3 is connected to the MCS regulating control system, the SCS sequential control system and the valve through one or more of communication protocols, hard wiring, bus, and industrial Ethernet gateway.

[0067] In a possible implementation, the ammonia injection pneumatic adjustment door opening refers to the measurement value of the measurement system and is automatically adjusted by the MCS regulation control system to improve the uniformity of ammonia injection.

[0068] In a possible implementation, the ammonia injection main pipe 1 is connected to an ammonia injection grid through a pipeline, the ammonia injection grid is connected to an ammonia injection branch pipe 6, and an ammonia injection hole is opened at the lower end of the ammonia injection branch pipe 6;

[0069] The ammonia injection main pipe 1 is also connected to a denitration main valve 2, and the denitration main valve 2 is arranged before the pneumatic regulating valve 4;

[0070] Specifically, the ammonia injection main pipe 1 is used to transport ammonia to the denitrification flue, and the denitrification main valve 2 is used to control the total amount of ammonia transported.

[0071] In a possible implementation, the boiler flue zone precise ammonia injection system further includes: a flue gas extraction pump, the flue gas extraction pump being installed in the CEMS control cabinet;

[0072] Specifically, the flue gas extraction pump can extract the flue gas in the denitrification flue and be used for online monitoring of the pollutant concentration in the flue gas.

[0073] Here’s how this application works:

[0074] The system first collects the sample gas in the flue by the complete extraction method through the sampling probe, and then processes the sample gas to meet the use and measurement requirements of the analyzer through filtering and cold drying and dehumidification methods, and then sends it to the analyzer for analysis. The analyzer displays the detection data in real time and transmits it to the DCS control system in the form of 4-20mA electrical signal. The DCS control system uses the received data to realize electrical control and data collection and transmission between other systems.

[0075] The advantages of this application are:

[0076] 1. This system reduces the sudden increase and surge of ammonia injection, making the variation range of NOx at the denitrification outlet less than ±5mg / m under stable working conditions. 3, the NOx fluctuation of net flue gas outlet is reduced by more than 30%, reducing the risk of exceeding the standard and ensuring environmental protection, economic and social benefits;

[0077] 2. Under any operating condition, the ammonia escape rate of this system is not more than 2.3mg / Nm3 (standard state, dry basis, 6% oxygen);

[0078] 3. This system can also reduce the threat to the safe operation of equipment in the tail flue and reduce the maintenance and operation costs caused by corrosion and blockage of downstream equipment;

[0079] In summary, the present application changes the previous automatic control strategy of "PID+feedforward control mode, taking the NOx concentration of the flue gas at the SCR inlet as the feedforward value to control the total amount of SCR ammonia injection", and determines the new technical solution of "enhancing the adaptability of ammonia injection to changes in operating conditions through denitrification main valve feedforward control and denitrification zone refined ammonia injection control", thereby achieving rapid, accurate and smooth full-load regulation of the SCR system to adapt to the new peak-shaving and frequency-regulation background.

[0080] Example 2

[0081] Based on the above examples, see Figure 4 This embodiment describes in detail a flue gas analysis workflow, which aims to monitor and analyze the components in industrial flue gas in real time and accurately, and through the collaborative work of a series of equipment, from flue gas sampling to final gas composition analysis, realizes automatic control and data feedback.

[0082] First, the flue gas sample is obtained through a sampling probe (CYTT) installed in the flue. The sampling probe is responsible for extracting representative flue gas samples from the flue to ensure that the sample can reflect the actual flue gas composition. The flue gas sample extracted by the sampling probe is then transferred to the subsequent processing unit by the sampling pump for further processing and analysis.

[0083] Before entering the analysis stage, the flue gas sample first passes through an air filter (AF) and a hydrophobic filter (WF) to perform preliminary purification on the sample. The air filter is used to remove solid particles in the sample, while the hydrophobic filter is responsible for removing excess moisture in the flue gas. The purpose of this filtration process is to ensure that the gas sample reaches the purity required for analysis and to avoid interference of particles and moisture in subsequent analysis.

[0084] Next, the gas sample enters the condensation chamber (LQ-1 and LQ-2) for condensation. Through the condensation chamber, the water vapor in the gas is cooled and condensed, ensuring that the gas sample is further dried to improve the accuracy of gas analysis. The function of the condensation chamber is to remove residual moisture to prevent water vapor from damaging the gas analysis instrument or affecting the analysis results.

[0085] The processed gas sample is transferred to the gas analyzer at a controlled flow rate under the control of a peristaltic pump (RDB). The main function of the peristaltic pump is to ensure that the sample gas can enter the gas analyzer at a stable and continuous flow rate to avoid measurement errors or unstable analysis due to flow fluctuations. By precisely controlling the gas flow rate, the system ensures the consistency and accuracy of the sample during the analysis process.

[0086] After receiving the sample, the gas analyzer detects its composition, focusing on the concentration of nitrogen oxides, oxygen and other gas components. The analysis results are fed back to the central control system in real time through the automation system, which is used to further adjust the flue gas treatment process to ensure that the emission meets environmental protection requirements. After the test is completed, the analyzed gas sample is discharged through the exhaust pipe, and the water generated by condensation is safely discharged through the condensate discharge system to prevent residual water from damaging the equipment.

[0087] The entire gas analysis process is automatically controlled and monitored by the PLC system and DCS system. After receiving feedback from the gas analyzer, the system will automatically adjust the operating parameters of related equipment to ensure that the system operates in the best state. At the same time, the zero calibration valve (Y1) is used to regularly calibrate the baseline value of the analyzer, and the purge stop valve (SVJZ) is used to remove residual gas in the sampling pipeline to prevent cross contamination of samples and ensure the long-term stability of the system operation.

[0088] The flue gas analysis system described in this embodiment can realize real-time monitoring of industrial flue gas components, and optimize the flue gas treatment process through automated control technology to ensure that emissions meet environmental protection requirements, while improving the system's operating efficiency and the accuracy of data analysis.

[0089] The above embodiments are only used to illustrate the technical solution of the present application, but not to limit it. The present application is not limited to the exact structure described above and illustrated in the accompanying drawings, and it cannot be determined that the specific implementation of the present application is limited to these descriptions. For ordinary technicians in the technical field to which the present application belongs, various changes and modifications made without departing from the concept of the present application should be deemed to belong to the protection scope of the present application.

Claims

1. A boiler flue zone precise ammonia injection system, characterized in that: include: Denitrification flue, ammonia injection system and measurement system; The denitrification flue comprises a denitrification inlet flue and a denitrification outlet flue, wherein the denitrification inlet flue is divided into a denitrification inlet flue A side and a denitrification inlet flue B side from the center of the flue, and the denitrification outlet flue is divided into a denitrification outlet flue A side and a denitrification outlet flue B side from the center of the flue, wherein the inlet ends of the denitrification inlet flue A side and the denitrification inlet flue B side are both connected with an ammonia injection mother pipe; The A side of the denitrification inlet flue and the B side of the denitrification inlet flue are both separately provided with an ammonia injection system, and the ammonia injection system is arranged in the flue along the width of a single side of the flue; The ammonia injection system is provided with four ammonia injection pneumatic adjustment door groups arranged one by one from the center of the flue to both sides, and each group of the ammonia injection pneumatic adjustment door groups includes an ammonia injection pneumatic adjustment door and manual doors of the same specifications but different quantities; The A side of the denitrification outlet flue and the B side of the denitrification outlet flue are each provided with a separate measurement system, the measurement system adopts a single-side 4-zone form, and the single-side 4 zones are arranged in parallel along the east-west direction of the flue cross section as a whole; The measurement system includes: multiple sampling probes and a CEMS system, each of the sampling probes corresponds to a single-side partition of the measurement system, and has the same number as the corresponding single zone of the measurement system, wherein on each side, the sampling probes with odd numbers are uniformly connected to the CEMS system, and the sampling probes with even numbers are uniformly connected to the CEMS system.

2. The boiler flue zone precise ammonia injection system according to claim 1 is characterized in that: The ammonia injection pneumatic adjustment gate is arranged on the ammonia injection branch pipe at the inlet of the denitration reactor, and adopts a pneumatic regulating valve to control the manual gate in the group; The manual doors distributed from the center of the flue to both sides are in groups of 4, 4, 3 and 3 respectively.

3. The boiler flue zone precise ammonia injection system according to claim 1 is characterized in that: The multiple sampling probes arranged on the A side of the denitrification outlet flue are all connected to the sampling power box on the A side, and the multiple sampling probes arranged on the B side of the denitrification outlet flue are all connected to the sampling power box on the B side; The A-side sampling power box and the B-side sampling power box are both connected to the distribution box via the on-site power supplies on both sides.

4. The boiler flue zone precise ammonia injection system according to claim 3 is characterized in that: The A-side sampling power box and the B-side sampling power box are connected to a DCS control system through cables. The DCS control system is used to realize electrical control and data collection and transmission. The electrical control includes sampling control and purging control of the probe.

5. The boiler flue zone precise ammonia injection system according to claim 3 is characterized in that: The A-side sampling power box and the B-side sampling power box also monitor the fault signal of the sampling probe and transmit the fault signal to the DCS control system.

6. The boiler flue zone precise ammonia injection system according to claim 1 is characterized in that: The plurality of sampling probes are respectively connected to a sampling valve, a sampling switching valve and a sampling valve. The sampling valve, the sampling switching valve and the sampling valve are independently numbered, and the numbers are the same as the corresponding sampling probes.

7. The boiler flue zone precise ammonia injection system according to claim 1 is characterized in that: Each of the sampling probes is connected to a solenoid valve, wherein on each side, the solenoid valves of the sampling probes with odd numbers are connected, and the solenoid valves of the sampling probes with even numbers are connected.

8. The boiler flue zone precise ammonia injection system according to claim 1 is characterized in that: Compressed air is introduced into the A side of the denitrification outlet flue and the B side of the denitrification outlet flue through compressed air pipes. The compressed air pipes pass through each of the sampling probes and are also all provided with a solenoid valve.

9. The boiler flue zone precise ammonia injection system according to claim 1 is characterized in that: In the ammonia injection system, each pneumatic regulating valve is connected to a remote control instrument, and each of the remote control instruments in the ammonia injection system is connected to the MCS regulating control system; In the measuring system, each solenoid valve is connected to a remote control instrument, and each of the remote control instruments in the measuring system is connected to the SCS sequential control system; The ammonia injection pneumatic adjustment door opening refers to the measured value of the measurement system and is automatically adjusted by the MCS regulation control system.

10. The boiler flue zone precise ammonia injection system according to claim 1, characterized in that: Also includes: A flue gas extraction pump is installed in a CEMS cabinet.

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