Control system and method based on centralized desulfurization and oxidation and branch tower monitoring

Abstract

The invention relates to the technical field of wet desulphurization, in particular to a control system and method based on centralized desulfurization and oxidation and branch tower monitoring. The system comprises an absorption tower, a slurry oxidation analyzer, a DCS control room, an oxidation fan, an oxidation air main pipe, a main pipe communication door, a branch tower flow adjusting device, a flowmeter and a flue gas analyzer, a liquid inlet of the slurry oxidation analyzer is communicated with the absorption towers, the slurry oxidation analyzer is electrically connected with the DCS control room, the number of the oxidation fans corresponds to that of the absorption towers, air outlets of the oxidation fans are connected to the absorption towers through oxidation air pipes, the mother pipe communication door is arranged on the oxidation air mother pipe, and the oxidation air pipes are communicated with the mother pipe communication door. The feeding end of the sub-tower flow adjusting device is connected with the oxidation air main pipe; the sulfur content in the flue gas is monitored in real time, the oxidation air volume is adjusted according to the detection result, and it is ensured that the oxidation air volume is reasonably distributed during multi-tower operation.

Description

Technical Field

[0001] The present invention relates to the technical field of wet flue gas desulfurization, and particularly to a control system and method based on centralized desulfurization oxidation and tower-by-tower monitoring. Background Art

[0002] The wet flue gas desulfurization oxidation technology is a wet flue gas desulfurization technology for treating sulfur dioxide (SO 2 ) in flue gas, and is particularly suitable for industrial emission sources such as thermal power plants. This technology combines the principles of oxidation reaction and wet flue gas desulfurization, and is usually used to reduce the sulfide content in industrial emissions, thereby achieving environmental protection and reducing air pollution. The basic principle of the wet flue gas desulfurization oxidation technology is to convert sulfur dioxide (SO 2 ) in flue gas into harmless sulfate or sulfuric acid through an oxidation reaction, and then remove these products through wet absorption.

[0003] The specific steps are as follows:

[0004] Oxidation reaction: By introducing an oxidant (such as oxygen, hydrogen peroxide, etc.), an oxidation reaction is carried out on sulfur dioxide in flue gas to convert SO 2 into sulfur trioxide (SO 3 ) or sulfate radical (SO 4 2- ). This oxidation reaction is usually carried out under certain temperature and pressure conditions to promote the reaction efficiency.

[0005] Wet absorption: The oxidation products (such as SO 3 ) react with water in the wet absorption tower to form sulfuric acid or other soluble sulfides. These products are absorbed by the absorption liquid (usually water or a solution containing an alkali), and finally the by-products such as sulfates are removed from the wet desulfurization tower through a water treatment system.

[0006] However, the existing wet flue gas desulfurization technology often encounters the following problems in use: In a traditional wet flue gas desulfurization device, the monitoring and control of the slurry oxidation level (especially the concentration of calcium sulfite) in the absorption tower are crucial, which directly affects the wet flue gas desulfurization efficiency and operating cost.

[0007] The prior art provides "An Automatic Monitoring and Centralized Control System and Method for the Oxidation Air Volume in Wet Flue Gas Desulfurization", with the publication number (CN113230846A). The innovation points of this technical solution are mainly reflected in the improvement of the automation and efficiency of the oxidation air volume monitoring system for wet flue gas desulfurization. First, the design of the slurry oxidation analyzer effectively avoids slurry precipitation, bubble interference, and temperature fluctuations, ensuring the accuracy of the measurement data. Second, the adjustment device of the fan improves the working efficiency of the fan and reduces energy consumption by changing the incoming air flow direction and speed, ensuring the stability of the oxidation air volume during the wet desulfurization process. These innovations solve problems such as low fan efficiency, data errors, and unstable processes in traditional systems.

[0008] (1) However, the air volume adjustment accuracy of this technical solution is relatively low. It usually relies on simple sensors and preset control strategies to adjust the air volume. This control method is not precise enough. Especially when the sulfur content in the flue gas and the wet desulfurization effect fluctuate greatly, it is unable to flexibly adjust the oxidation air volume according to real-time changes. This can lead to energy consumption waste caused by excessive oxidation or low wet desulfurization efficiency caused by insufficient oxidation.

[0009] (2) Insufficient adaptability to special working conditions. The system does not have the ability to fully handle special working conditions. For example, when there are large differences in the sulfur content of different absorption towers, the traditional control system cannot reasonably allocate the oxidation air volume. This leads to insufficient processing capacity during multi-tower control and difficulty in fine adjustment for such special situations, resulting in insufficient processing capacity or energy waste in a certain tower. This is also a technical defect that has existed in this field. Summary of the Invention

[0010] The main purpose of the present invention is to provide a control system and method based on centralized and tower-by-tower monitoring of desulfurization oxidation to effectively solve the problems of low air volume adjustment accuracy and insufficient processing capacity of the existing technical solutions mentioned in the background technology.

[0011] To achieve the above purpose, the technical solution adopted by the present invention is:

[0012] A control system and method based on centralized and tower-by-tower monitoring of desulfurization oxidation, including: A control system and method based on centralized and tower-by-tower monitoring of desulfurization oxidation, including:

[0013] Absorption towers, with at least two absorption towers erected;

[0014] Slurry oxidation analyzer, the liquid inlet of the slurry oxidation analyzer is connected to the absorption tower;

[0015] DCS control room, the slurry oxidation analyzer is electrically connected to the DCS control room;

[0016] An oxidation blower, the number of the oxidation blowers provided corresponding to the absorption tower;

[0017] An oxidation air main pipe, the air outlets of the oxidation blowers connected together through the oxidation air main pipe;

[0018] A main pipe connection gate, the main pipe connection gate provided on the oxidation air main pipe;

[0019] A flow rate regulating device for each tower, the feed end of the flow rate regulating device for each tower connected to the oxidation air main pipe, the discharge end of the flow rate regulating device for each tower connected to the two absorption towers;

[0020] A flow meter, the flow meter installed inside the absorption tower, and the flow meter electrically connected to the DCS air volume control room;

[0021] A flue gas analyzer, the flue gas analyzer installed on the flue gas pipeline of the absorption tower, the flue gas analyzer electrically connected to the DCS air volume control room;

[0022] An intelligent electricity meter, the intelligent electricity meter installed at the bus of any power supply cable, and the intelligent electricity meter electrically connected to the DCS air volume control room.

[0023] The oxidation blower is electrically connected to the DCS air volume control room.

[0024] The flow rate regulating device for each tower is electrically connected to the DCS air volume control room.

[0025] A method for controlling the air volume by the air volume control system according to any one of the above, the method comprising:

[0026] S1. Initial setting of the total air volume

[0027] S101. Initially set the total oxidation air volume according to the unit load and the sulfur content in the inlet flue gas;

[0028] S102. Air volume adjustment based on the reading of the SOA of the slurry oxidation analyzer;

[0029] S2. Determine the reading of the SOA of the slurry oxidation analyzer every 10 minutes, and the air volume control range is 0 - 100 ppm;

[0030] S3. Tower-by-tower control step, with two absorption towers running simultaneously, including;

[0031] S301. Calculate the total sulfur content at the inlets of the first and second absorption towers respectively,

[0032] S302. According to the actual on-site situation, test and obtain the average value for equalizing the air volume of the two units at different loads, and set it as the initial value of the opening of the tower-by-tower valve,

[0033] S303. Adjust the tower flow rate. Determine the level of the total sulfur content at the inlets of the first and second absorption towers based on the total sulfur content at the inlet.

[0034] S4. Fine-tune the tower flow rate. Based on the SOA reading, judge the SOA readings of each tower every 30 minutes, and the air volume control range is 50 - 250 ppm.

[0035] S5. Control the tower flow rate in special cases.

[0036] In step S303, the reference value of the first flowmeter = the reading of the second flowmeter × (total sulfur content in the first absorption tower / total sulfur content in the second absorption tower).

[0037] In step S303, if there is a difference in the total sulfur content between the first absorption tower and the second absorption tower, then check the relationship between the readings of the flowmeters of the two absorption towers and the reference value every 1 minute. When the reading of the flowmeter of the absorption tower with a lower sulfur content exceeds the reference value by 5%, reduce the opening of the tower flow rate adjustment device by 2%. When the reading of the flowmeter of the absorption tower with a lower sulfur content is less than the reference value by 5%, increase the opening of the first tower flow rate adjustment device by 2%. When it is within the reference value range, the opening remains unchanged.

[0038] The S4 step further includes:

[0039] S401. For the two absorption towers, when the SOA reading of this tower < 50 ppm, the opening of the first tower flow rate adjustment device is adjusted down by 5% each time;

[0040] S402. When the SOA readings of the two towers > 250 ppm, the opening of the first tower flow rate adjustment device is adjusted up by 5% each time.

[0041] The S5 step further includes:

[0042] S501. When the total sulfur content of the two absorption towers ≥ the total sulfur content of the second absorption tower, the opening of the first tower flow rate adjustment device remains unchanged at 100%;

[0043] S502. When the total sulfur content of the two absorption towers < the total sulfur content of the second absorption tower, the reference value of the first flowmeter satisfies the above calculation principle and participates in the control of the first tower flow rate adjustment device.

[0044] Compared with the prior art, the beneficial effects of the present invention are:

[0045] (1) Through the intelligent automation control system, the present invention realizes the precise adjustment of the oxidation air volume and the air volume of each tower. This system combines the real-time feedback of the oxidation situation, the load rate, the sulfur content in the inlet flue gas, and the data of the slurry oxidation analyzer (SOA) to ensure the safe and economic operation of the wet flue gas desulfurization process. This solution combines various real-time feedback data and flexibly adjusts within the range of 0 - 100 PPM. It determines once every 10 minutes and increases or decreases the air volume according to the SOA value. Especially in different PPM value ranges, different air volume adjustment amplitudes are adopted (for example, a 5% decrease when 0 - 20 PPM, and a 5% increase when 80 - 100 PPM), making the system's response to the change of sulfur content in the flue gas more refined and real-time. And through gradual adjustment, the possibility of excessive fluctuation is reduced. Through this feedback-based adjustment mechanism, the system can ensure that the oxidation air volume is always within the most suitable range, avoiding the energy consumption waste caused by excessive oxidation and the low efficiency of wet flue gas desulfurization caused by insufficient oxidation, thus realizing the efficient and energy-saving operation of the wet flue gas desulfurization process.

[0046] (2) In addition, through real-time data collection and analysis, the intelligent control system can automatically adjust the air volume distribution according to the actual situation to ensure the reasonable distribution of air volume when multiple absorption towers are operating simultaneously, prevent some towers from being overloaded or having insufficient air volume, and ensure the balance and stability of the wet flue gas desulfurization effect. Ensure that the wet flue gas desulfurization equipment can maintain the best operating state under various working conditions, thus greatly reducing the operating cost and improving the safety and long life of the equipment. For special situations, there are specific principles for the flow control of each tower. When the sulfur content in a certain absorption tower is higher or lower than that of another tower, the relationship between the readings of two flow meters and the reference value is detected every 1 minute. When the difference in sulfur content exceeds 5% of the reference value, the opening of the corresponding flow regulating device for each tower is adjusted. Such a design ensures the reliability and stability of the wet flue gas desulfurization process. The aim is to optimize the wet flue gas desulfurization effect by precisely controlling the oxidation air volume and the flow of each tower. By real-time monitoring the sulfur content in the flue gas, adjusting the oxidation air volume according to the detection results, and ensuring the reasonable distribution of the oxidation air volume during multi-tower operation. This method can effectively improve the efficiency of wet flue gas desulfurization, reduce the operating cost, and has a high degree of automation, facilitating long-term stable operation, ensuring the safe, economic, and efficient operation of the wet flue gas desulfurization process. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification, and are used to explain the present invention together with the specific embodiments of the present invention, and do not constitute a limitation to the present invention.

[0048] Figure 1 It is a schematic diagram of the overall system of the present invention.

[0049] Figure 2 It is a schematic diagram of a partial system of the present invention.

[0050] Figure 3 This is a schematic diagram of the overall steps of the present invention.

[0051] Figure 4 This is a schematic diagram of step S303 of the present invention.

[0052] Figure 5 This is a schematic diagram of step S4 of the present invention.

[0053] Figure 6 This is a schematic diagram of step S5 of the present invention.

[0054] Reference numerals in the figure: 1, absorption tower; 2, slurry oxidation analyzer; 3, DCS control room; 4, oxidation fan; 5, oxidation air main pipe; 6, main pipe connection door; 7, tower flow regulating device; 8, flowmeter; 9, flue gas analyzer; 10, intelligent electricity meter. Specific embodiments

[0055] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0056] In the description of the present invention, it should also be noted that, unless otherwise clearly defined and limited, the terms "set", "arrange", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] As Figure 1-6 shown, the present invention provides the following technical solutions:

[0058] Embodiment 1

[0059] A control system based on desulfurization oxidation concentration and sub-tower monitoring, comprising: an absorption tower 1, a slurry oxidation analyzer 2, a DCS control room 3, an oxidation fan 4, an oxidation air main pipe 5, a main pipe connection door 6, a sub-tower flow regulating device 7, a flowmeter 8, a flue gas analyzer 9, and an intelligent electricity meter 10;

[0060] There are at least two absorption towers 1, which are the core equipment for wet flue gas desulfurization reaction. The flue gas contacts with the limestone slurry in them to carry out the wet flue gas desulfurization reaction. The inlet of the slurry oxidation analyzer 2 is connected to the absorption tower 1 and is arranged outside the absorption tower 1. Its inlet is connected to the absorption tower 1 and is used to analyze the slurry oxidation index in the absorption tower 1, that is, the concentration of the sulfite, the remaining product of slurry oxidation. The slurry oxidation analyzer 2 is electrically connected to the DCS control room 3; it is arranged on one side of the slurry oxidation analyzer 2, receives the measurement signal of the slurry oxidation analyzer 2, and is used to control the damper opening of the inlet regulating device of the oxidation blower 4.

[0061] In this embodiment, as Figure 1-2 shown, the number of oxidation blowers 4 is corresponding to that of the absorption towers 1. The oxidation blowers 4 are electrically connected to the DCS control room 3 and provide the air required for the oxidation reaction. The oxidation air main pipe 5 connects the outlets of each oxidation blower 4 together to achieve the centralized control and distribution of the oxidation air. The main pipe connection door 6 is arranged on the oxidation air main pipe 5 and is used to switch the source of the oxidation air to achieve the independent control of each wet flue gas desulfurization absorption tower 1. The feeding end of the tower-by-tower flow regulating device 7 is connected to the oxidation air main pipe 5, and the discharging end of the tower-by-tower flow regulating device 7 is connected to the two absorption towers 1 and is used to adjust the oxidation air flow of each absorption tower 1 and perform independent adjustment according to the specific conditions of each tower. The flowmeter 8 is installed inside the absorption tower 1, and the flowmeter 8 is electrically connected to the tower-by-tower flow regulating device 7 and is used to measure the oxidation air flow of each absorption tower 1 and provide a reference value for the tower-by-tower flow regulating device 7. The flue gas analyzer 9 is installed in the flue gas pipeline of the absorption tower 1, and the flue gas analyzer 9 is electrically connected to the DCS control room 3 and is used to measure the sulfur content in the inlet flue gas. The intelligent electricity meter 10 is installed at the bus of any power supply cable, and the intelligent electricity meter 10 is electrically connected to the DCS control room 3 and is used to measure the unit load.

[0062] Specifically, the absorption tower 1, as the core equipment for wet flue gas desulfurization reaction, receives the flue gas from the flue gas pipeline. The flue gas contacts with the limestone slurry inside the absorption tower 1, and the wet flue gas desulfurization reaction occurs. The flue gas analyzer 9 is installed in the flue gas pipeline of the absorption tower 1 to analyze the sulfur content of the inlet flue gas and send the results to the DCS control room 3. The intelligent electricity meter 10 is installed at the bus of the power supply cable to measure the unit load condition and send the data to the DCS control room 3. The DCS control room 3 makes the initial setting of the total oxidation air volume and other air volume control operations according to parameters such as the unit load. The liquid inlet of the slurry oxidation analyzer 2 is connected to the absorption tower 1 to analyze the oxidation index in the slurry and send the measured signal to the DCS control room 3. The DCS control room 3 integrates the above data to obtain the air supply volume. The number of oxidation blowers 4 corresponds to the absorption tower 1. After starting, it inhales air from the outside and pressurizes it, transports the air into the absorption tower 1 through the oxidation air pipe, and adjusts the air supply volume according to the control signal of the DCS control room 3. The oxidation air main pipe 5 connects the air outlets of each oxidation blower 4 together, playing the role of centralized control and distribution of oxidation air. The main pipe connection valve 6 can be operated to open or close according to the control instruction. The tower-by-tower flow regulating device 7 makes independent adjustments according to the specific conditions of each tower, including setting the initial value of the tower-by-tower valve opening according to the actual situation on site, calculating the reference value of the flowmeter 8 and adjusting the opening according to the high or low situation judged by the total sulfur content at the inlet, and making fine adjustments according to the SOA readings of each tower. There are also corresponding control principles in special situations. The flowmeter 8 is installed inside the absorption tower 1 to continuously measure the oxidation air flow and send the data to the tower-by-tower flow regulating device 7.

[0063] Embodiment 2

[0064] A control method based on centralized and tower-by-tower monitoring of desulfurization oxidation includes:

[0065] As Figure 3-6 shown, through the intelligent automation control system, the accurate adjustment of the oxidation air volume and the tower-by-tower air volume is realized. This system combines the real-time feedback of the oxidation situation, the load rate, the sulfur content of the inlet flue gas and the data of the slurry oxidation analyzer SOA to ensure the safe and economic operation of the wet flue gas desulfurization process. The specific operation process can be divided into the following aspects:

[0066] S1. Initial setting of the total air volume

[0067] S101. Make the initial setting of the total oxidation air volume according to the unit load and the sulfur content of the inlet flue gas. The initial setting of the oxidation air volume is based on the unit load and the sulfur content of the inlet flue gas. For the initial air volume setting, the system relies on these two parameters to calculate the appropriate oxidation air volume;

[0068] S102. Air volume adjustment based on the indication of the slurry oxidation analyzer SOA.

[0069] S2. Determine the reading of the Slurry Oxidation Analyzer (SOA) every 10 minutes. The system obtains real-time oxidation effect information by continuously monitoring the data of the SOA. The SOA data reflects the effect of the oxidant (i.e., the degree of oxidation) in the wet flue gas desulfurization slurry. According to different SOA values, the system will make the following adjustments:

[0070] The control range is 0 - 100 PPM. Determine it every 10 minutes.

[0071]

[0072]

[0073] This air volume adjustment is based on the deviation between the oxidation effect SOA and the target value, ensuring that the dynamic adjustment of the oxidation air volume can be consistent with the wet flue gas desulfurization effect. Through this real-time feedback mechanism, it can ensure the timely adjustment of the oxidation air volume, avoid too low or too high wet flue gas desulfurization effect caused by inappropriate air volume, thereby optimizing the wet flue gas desulfurization process, reducing energy waste, and improving economy.

[0074] S3. Tower separation control steps (taking the simultaneous operation of two absorption towers as an example), intelligent tower separation air volume is automatically distributed according to demand:

[0075] The automatic distribution system of the tower separation air volume ensures that when multiple absorption towers operate simultaneously, the oxidation air volume can be accurately distributed according to the demands of different towers.

[0076] S301. Calculate the total sulfur content at the inlets of the first and second absorption towers respectively,

[0077] S302. According to the actual on-site situation, test and obtain the average value of air volume equalization for the two units under different loads, and set it as the initial value of the tower separation valve opening,

[0078] S303. Tower separation flow regulation, judge the high and low situations of the total sulfur content at the inlets of the first and second absorption towers according to the total sulfur content at the inlets;

[0079] Reference value of the first flowmeter = Reading of the second flowmeter × (Total sulfur content of the first absorption tower / Total sulfur content of the second absorption tower).

[0080] If the total sulfur content of the first absorption tower is lower than that of the second absorption tower, detect the relationship between the reading of the flowmeter of the first absorption tower and the reference value every 1 minute. When the reading of the flowmeter of the first absorption tower with low sulfur content exceeds the reference value by 5%, reduce the opening of the first tower separation flow regulation device by 2%. When the reading of the flowmeter of the first absorption tower with low sulfur content is lower than the reference value by 5%, increase the opening of the first tower separation flow regulation device by 2%. When it is within the reference value range, the opening remains unchanged.

[0081] If the total sulfur content in the first absorption tower is higher than that in the second absorption tower, the relationship between the flowmeter reading of the second absorption tower and the reference value is detected every 1 minute. When the flowmeter reading of the second absorption tower with a lower sulfur content exceeds the reference value by 5%, the opening of the flow rate regulating device of the second fractionating tower is reduced by 2%. When the flowmeter reading of the second absorption tower with a lower sulfur content is lower than the reference value by 5%, the opening of the flow rate regulating device of the second fractionating tower is increased by 2%. When it is within the reference value range, the opening remains unchanged.

[0082] This distribution method based on the inlet sulfur content can ensure that when each absorption tower processes flue gas with different sulfur contents, the allocated air volume is consistent with the actual demand, thereby improving the overall wet desulfurization effect.

[0083] S4. Fine adjustment of the tower flow rate (according to the SOA reading), judge the SOA reading of each tower every 30 minutes (the control range is 50 - 250 ppm);

[0084] S401. For the two absorption towers, when the SOA reading of this tower < 50 ppm, the opening of the first fractionating tower flow rate regulating device is adjusted down by 5% each time;

[0085] S402. When the SOA readings of the two towers > 250 ppm, the opening of the first fractionating tower flow rate regulating device is adjusted up by 5% each time.

[0086] This adjustment based on the SOA data can ensure the continuous optimization of the slurry oxidation effect, avoid the oxidation effect of the system being too weak or too strong in some towers, and ensure that each tower can exert its best performance.

[0087] S5. Flow rate control of the fractionating tower in special cases,

[0088] S501. When the total sulfur content of the two absorption towers ≥ the total sulfur content of the second absorption tower, the opening of the first fractionating tower flow rate regulating device remains unchanged at 100%;

[0089] S502. When the total sulfur content of the two absorption towers < the total sulfur content of the second absorption tower, the reference value of the first flowmeter meets the above calculation principle and participates in the control of the first fractionating tower flow rate regulating device.

[0090] In the adjustment of the oxidation air volume and the fractionating tower air volume, the automatic control of the system can work together to ensure the optimization of the overall wet desulfurization effect. The adjustment of the oxidation air volume is based on the change of the SOA data, while the distribution of the fractionating tower air volume is dynamically adjusted through the proportional relationship between the real-time flow data and the sulfur content. The combination of the two can effectively balance the load of the entire wet desulfurization system, reduce energy consumption and improve the wet desulfurization efficiency.

[0091] Oxidation air volume control: Based on the real-time feedback of SOA data, load rate and inlet flue gas sulfur content, perform dynamic adjustment to ensure that the oxidation effect matches the demand.

[0092] Flue gas volume distribution for each tower: Based on the sulfur content of the inlet flue gas, it is accurately distributed according to the requirements of each absorption tower. At the same time, fine-tuning of the air volume is achieved through the feedback information of SOA to ensure the best wet flue gas desulfurization effect for each absorption tower.

[0093] Such an intelligent control system enables the wet flue gas desulfurization process to flexibly respond to different working conditions, achieving effective utilization of energy and stable economic operation.

[0094] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A control system and method based on centralized desulfurization and oxidation and sub-tower monitoring, characterized in that: include: An absorption tower (1), wherein at least two absorption towers (1) are erected; A slurry oxidation analyzer (2), wherein the liquid inlet of the slurry oxidation analyzer (2) is connected to the absorption tower (1); A DCS control room (3), the slurry oxidation analyzer (2) being electrically connected to the DCS control room (3); Oxidation fans (4), the number of the oxidation fans (4) corresponding to the number of the absorption towers (1); An oxidation air main pipe (5), the air outlets of each oxidation fan (4) are connected together through the oxidation air main pipe (5); A main pipe communication door (6), wherein the main pipe communication door (6) is arranged on the oxidation air main pipe (5); A sub-tower flow regulating device (7), wherein the feed end of the sub-tower flow regulating device (7) is connected to the oxidation air main pipe (5), and the discharge end of the sub-tower flow regulating device (7) is connected to the two absorption towers (1); A flow meter (8), the flow meter (8) being installed inside the absorption tower (1), and the flow meter (8) being electrically connected to the DCS air volume control room (3); A flue gas analyzer (9), the flue gas analyzer (9) being installed in the flue gas duct of the absorption tower (1), and the flue gas analyzer (9) being electrically connected to the DCS air volume control room (3); A smart electric meter (10), wherein the smart electric meter (10) is installed at a busbar of any power supply cable, and the smart electric meter (10) is electrically connected to the DCS air volume control room (3).

2. A control system based on centralized desulfurization and oxidation and sub-tower monitoring according to claim 1, characterized in that: The oxidation fan (4) is electrically connected to the DCS air volume control room (3).

3. A control system based on centralized desulfurization and oxidation and sub-tower monitoring according to claim 1, characterized in that: The sub-tower flow regulating device (7) is electrically connected to the DCS air volume control room (3).

4. A method for controlling air volume according to a control system according to any one of claims 1 to 3, characterized in that: The method comprises: S1. Initial setting of total air volume S101, initially setting the total oxidation air volume according to the unit load and the sulfur content of the inlet flue gas; S102, air volume adjustment based on the SOA reading of the slurry oxidation analyzer; S2. Determine the reading of the slurry oxidation analyzer SOA every 10 minutes, and the air volume control range is 0-100ppm; S3, the tower control step, wherein two absorption towers are operated simultaneously, comprises: S301, respectively calculating the total sulfur content at the inlets of the first and second absorption towers, S302. According to the actual situation on site, the average value of the air volume distribution of the two units under different loads is obtained through experiments, and it is set as the initial value of the opening of the tower valve. S303, regulating the flow of the sub-towers, judging the total sulfur content at the inlets of the first and second absorption towers according to the total sulfur content at the inlets; S4. Fine adjustment of tower flow rate: Based on the SOA reading, the SOA reading of each tower is judged every 30 minutes, and the air volume control range is 50-250ppm; S5. Tower flow control in special situations.

5. The method according to claim 4, characterized in that In step S303, the first flow meter reference value = the second flow meter reading × the total sulfur content in the first absorption tower / the total sulfur content in the second absorption tower.

6. The method according to claim 4, characterized in that In step S303, if there is a difference in the total sulfur content of the first absorption tower and the total sulfur content of the second absorption tower, the relationship between the flow meter readings of the two absorption towers and the reference value is detected every 1 minute. When the flow meter reading of the absorption tower with low sulfur content exceeds the reference value by 5%, the opening of the sub-tower flow regulating device is reduced by 2%. When the flow meter reading of the absorption tower with low sulfur content is lower than the reference value by 5%, the opening of the first sub-tower flow regulating device is increased by 2%. When it is within the reference value range, the opening remains unchanged.

7. The method according to claim 4, characterized in that The step S4 further includes: S401. For two absorption towers, when the SOA reading of the tower is less than 50 ppm, the opening of the flow regulating device of the first sub-tower is reduced by 5% each time; S402. When the SOA readings of the two towers are greater than 250 ppm, the opening of the flow regulating device of the first sub-tower is increased by 5% each time.

8. The method according to claim 4, characterized in that The step S5 further includes: S501, when the total sulfur content of the two absorption towers is ≥ the total sulfur content of the second absorption tower, the flow regulating device of the first sub-tower remains open at 100%; S502: When the total sulfur content of the two absorption towers is less than the total sulfur content of the second absorption tower, the reference value of the first flow meter meets the above calculation principle and participates in the control of the flow regulating device of the first sub-tower.

Images